ABST 201-300

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201: Bush K, Hillier S. A controlled study of caudal epidural injections of triamcinolone plus procaine for the management of intractable sciatica. Spine 1991 May;16(5):572-5

Department of Rheumatology, Royal Free Hospital, London.

The management of sciatica due to lumbar nerve root compromise remains controversial, probably because few well-controlled studies of conservative management have been performed. This preliminary study assesses the efficacy of epidural injections of 80 mg triamcinolone acetonide plus 0.5% procaine hydrochloride in saline, administered via the caudal route, in a double-blind, placebo controlled trial with 1 year follow-up. Twenty-three patients were entered into the study: 12 received treatment and 11 placebo. The active group showed significant pain relief (P = 0.02) and a significant increase in mobility (P = 0.01) at 4 weeks, which resulted in improved quality of life (P = 0.02). At 1 year, subjective and objective measures improved in both groups. The improvement was greater in the actively treated group, but only the objective assessment (straight leg raise) was statistically significant.

202: Cuckler JM, Bernini PA, Wiesel SW, Booth RE Jr, Rothman RH, Pickens GT. The use of epidural steroids in the treatment of lumbar radicular pain. A prospective, randomized, double-blind study. J Bone Joint Surg Am 1985 Jan;67(1):63-6

Seventy-three patients with lumbar radicular pain syndromes were treated in a prospective, randomized, double-blind fashion with either seven milliliters of methylprednisolone acetate and procaine or seven milliliters of physiological saline solution and procaine. All patients had radiographic confirmation of lumbar nerve-root compression, consistent with the clinical diagnosis of either an acute herniated nucleus pulposus or spinal stenosis. No statistically significant difference was observed between the control and experimental patients with either acute disc herniation or spinal stenosis. Long-term follow-up, averaging twenty months, failed to demonstrate the efficacy of a second injection of epidural steroids administered to the patients whose pain did not respond within twenty-four hours to an injection of either eighty milligrams of methylprednisolone acetate combined with five milliliters of 1 per cent procaine or two milliliters of sterile saline combined with five milliliters of 1 per cent procaine. Therefore, a decision to use epidural steroids must be made with the realization that we failed to demonstrate its clinical efficacy in this study and that reports of serious complications of this procedure have been published.

205: Klenerman L, Greenwood R, Davenport HT, White DC, Peskett S. Lumbar epidural injections in the treatment of sciatica. Br J Rheumatol 1984 Feb;23(1):35-8

A randomized trial of lumbar epidural injections for the treatment of acute sciatic pain was carried out. All the patients had unilateral sciatica for less than six months and had never previously been treated in hospital for their backs. The treatments used were 20 ml normal saline, 80 mg Depomedrone in normal saline made up to 20 ml, 20 ml, 20 ml 0.25% bupivacaine solution and needling with a standard Touhy injection needle into the interspinous ligament but with no injection. The patients improved at about the same rate for all four treatments. Overall, 75% of the patients improved or were cured. As some of these were in the group treated by needling of the interspinous ligament, it seems likely that the epidural injections administered achieved effects partially as a placebo and partially by virtue of the natural history of the acute sciatic syndrome.

206: Ridley MG, Kingsley GH, Gibson T, Grahame R. Outpatient lumbar epidural corticosteroid injection in the management of sciatica. Br J Rheumatol 1988 Aug;27(4):295-9

Rheumatology Unit, Guy's Hospital, London.

The value of epidural injections of corticosteroid as an outpatient treatment of sciatica has been hitherto uncertain. An epidural injection of 80 mg methylprednisolone in 10 ml physiological saline was compared with an interspinous injection of 2 ml physiological saline in a double blind fashion amongst 39 outpatients. Significant differences of pain relief were seen between the two groups within 2 weeks. This benefit disappeared for six (35%) patients within 6 months of treatment although 11 (65%) successfully treated subjects had sustained improvement up to this time. Outpatient epidural injections of corticosteroid are thus a useful short-term means of relieving pain in sciatica but probably have little effect on the long-term natural history of symptoms. Factors associated with a failure to respond to epidural steroid injections are discussed.

207: Snoek W, Weber H, Jorgensen B. Double blind evaluation of extradural methyl prednisolone for herniated lumbar discs. Acta Orthop Scand 1977;48(6):635-41

A double blind study was carried out in 51 patients suffering from lumbar root compression syndrome of 12 days to 36 weeks duration. All patients had signs, symptoms and radiological abnormalities related to a herniated lumbar disc. Each patient received an extradural injection of either 2 ml (80 mg) methyl prednisolone or 2 ml normal saline solution. Neurological examination and interview of the patients with the aid of a questionnaire before and after extradural injection failed to demonstrate any statistically significant difference in outcome between the two groups. At follow-up 14 +/- 6 months after extradural injection 58.3 per cent of the patients in the control group and 51.9 per cent of the patients in the treatment group had undergone surgical treatment with laminectomy. Our results indicate that a single extradural injection of methyl prednisolone (80 mg) is no more effective than a placebo injection in relieving chronic symptoms due to myelographically demonstrable lumbar disc herniation.

208: Kepes ER, Duncalf .D Treatment of backache with spinal injections of local anesthetics, spinal and systemic steroids. A review. Pain 1985 May;22(1):33-47

Low back pain and sciatica have been treated with peridural local anesthetics for over 80 years and with epidural and subarachnoid steroid injections for a quarter of a century. This review surveyed the literature concerning the evolution, pathophysiology, complications and results of this type of therapy. The volume injected and the method used vary with different physicians and no standard has been established. Good results from this treatment which vary from 20 to 95% decrease on long-term follow up. Statistical significance is absent if compared with other forms of therapy. It is the authors' opinion that the rationale for the use of spinal local analgesics or steroids or intramuscular steroids has not been scientifically proven. Complications with the use of subarachnoid steroids are sufficiently serious that this form of therapy should be condemned. In this age of accountability it is imperative that therapies with questionable benefits should be critically evaluated.

209: Rocco AG, Frank E, Kaul AF, Lipson SJ, Gallo JP Epidural steroids, epidural morphine and epidural steroids combined with morphine in the treatment of post-laminectomy syndrome. Pain 1989 Mar;36(3):297-303

Pain Treatment Service, Brigham and Women's Hospital, Boston, MA 02115.

Epidural morphine injection followed by a steroid has been reported to be effective for the post-laminectomy pain ('failed back') syndrome. This double-blind, parallel study was undertaken to evaluate that mode of therapy. Twenty-two patients who had undergone at least one prior laminectomy, who were still symptomatic, were randomized to receive 50 mg of lidocaine epidurally with: (a) 75 mg triamcinolone diacetate (TR); or (b) 8 mg of preservative-free morphine (MP); or (c) both (TR and MP), at 1 month intervals for 3 consecutive months. The spinal interspace identified with the patients' pain complaint was the site of injection. For each treatment, patients were admitted to the Clinical Research Center for 24 h and their condition continuously monitored with a pulse oximeter and apnea monitor. Five to 7 patients in each group had pain relief for less than 1 month. No patient given morphine had pain relief for more than 1 month. Life-threatening ventilatory depression occurred in the group given triamcinolone and morphine. The use of morphine alone or combined with slow release triamcinolone does not appear to be appropriate for the treatment of the post-laminectomy pain syndrome.

210 Nelemans PJ, de Bie RA, de Vet HC, Sturmans F. Injection therapy for subacute and chronic benign low back pain. Cochrane Database Syst Rev 2000; (2) :CD001824 Epidemiology, University of Maastricht, Debyeplein 1, Maastricht, Netherlands, 6200 MD. Patty.Nelemans@epid.unimaas.nl

BACKGROUND: Injection with anaesthetics and/or steroids is one of the treatment modalities used in patients with chronic low back pain which needs evaluation with respect to the effectiveness on short and long term pain relief. OBJECTIVES: To evaluate the effectiveness of injection therapy in patients with low back pain lasting longer than one month. We distinguished between three injection sites: facet joint, epidural or local injections. SEARCH STRATEGY: We searched the Medline and Embase databases up to 1996 and other search methods as advocated by the Back Review Group search strategy. Abstracts and unpublished studies were not included. SELECTION CRITERIA: Randomized controlled trials of injection therapy for pain relief (although additional treatments were allowed) in patients with benign low back pain lasting longer than one month and not originating from cancer. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed the trials for methodological quality. Subgroup analyses were made between trials with different control groups (placebo and active injections), with different injection site (facet joint, epidural and local injection), and timing of outcome measurement (short and long term). Within the resulting 12 subcategories of studies (2*3*2), the overall relative risks and corresponding 95% confidence intervals were estimated, using a random effects model (DerSimonian and Laird). In the case of trials in which control groups were active injections, we refrained from pooling the results. MAIN RESULTS: Twenty-one randomized trials were included in this review. All studies involved patients with low back pain lasting longer than one month. Only 11 studies compared injection therapy with placebo injections (explanatory trials). The methodologic quality of many studies was low: only 8 studies had a methodologic score of 50 or more points. There were only three well designed explanatory clinical trials: one on injections into the facet joints with a short-term RR of 0.89 (95% CI: 0.65-1.21) and a long-term RR of 0.90 (95% CI: 0.69-1.17); one on epidural injections with a short-term RR of 0.94 (95% CI: 0.76-1.15) and a long-term RR of 1.00 (95% CI: 0.71-1.41); and one on local injections with a long-term RR of 0.79 (95% CI: 0.65-0.96). Within the 6 subcategories of explanatory studies the pooled RRs with 95% confidence intervals were: facet joint, short-term: RR=0.89 (0.65-1.21); facet joint, long-term: RR=0.90 (0.69-1.17); epidural, short-term: RR=0.93 (0. 79-1.09); epidural, long-term: RR=0.92 (0.76-1.11); local, short-term: RR=0.80 (0.40-1.59); local, long-term: RR=0.79 (0.65-0. 96). REVIEWER'S CONCLUSIONS: Convincing evidence is lacking on the effects of injection therapies for low back pain. There is a need for more, well designed explanatory trials in this field.

211: Coan RM, Wong G, Ku SL, Chan YC, Wang L, Ozer FT, Coan PL The acupuncture treatment of low back pain: a randomized controlled study. Am J Chin Med 1980 Spring-Summer;8(1-2):181-9

The acupuncture treatment situation was beneficial to the majority of people with low back pain. This was shown by the use of short-term controls and long-term controls, although the latter were not intended in the study design. After acupuncture, there was a 51% pain reduction in the average pain score in the Immediate Treatment Group. The short-term controls, the Delayed Treatment Group, had no reduction whatsoever in their pain scores at the comparable followup period. Later, the Delayed Treatment Group bere also treated by acupuncturists, and reported 62% less pain. When these two treatment groups were compared at 40 weeks with long-term controls (Inadequate Treatment Group), the Inadequate Treatment Group still had the same pain scores, on the average, as when they enrolled in the study. Both treatment groups, on the average, had 30% lower pain scores. Furthermore, 58% of the treatment groups felt that they were definitely improved at 40 weeks, while only 11% of the Inadequate Treatment Group felt definitely improved at 40 weeks.

212: Acupuncture and chronic pain mechanisms. Ghia JN, Mao W, Toomey TC, Gregg JM Pain 1976 Sep;2(3):285-99

Forty patients with chronic pain below the waist level not amenable to conventional medical and/or surgical treatment were randomly assigned to one or two different methods of acupuncture, after studying the underlying pain mechanisms using a Multidisciplinary Pain Clinic approach and the differential spinal block (DSB). One group received acupuncture needling in the classical acupuncture points referred to as meridian loci needling (MLN) and the other group received tender area needling (TAN) with needles inserted in the dermatomal distribution of the painful areas. The responses between the two groups showed no significant difference. Results were then related to the predetermined somatopsychological basis of the individual's pain problems as classified by the DSB. A group of patinets in whom pain relief occurred upon subarachnoid injection of 0.25% procaine followed by sympathetic blockade or 0.5% procaine injection followed by hypalgesia without motor loss, also reported maximum subjective improvement in their pain level following acupuncture therapy performed at a later time. The other group of patients in whom pain persisted despite sensory and motor blockade (1% procaine) responded very poorly to acupuncture therapy. DSB was found to be complimentary to acupuncture therapy in that it facilitated patient selection for the therapy.

213: Ghia JN, Mao W, Toomey TC, Gregg JM. Acupuncture and chronic pain mechanisms. Pain 1976 Sep;2(3):285-99

Forty patients with chronic pain below the waist level not amenable to conventional medical and/or surgical treatment were randomly assigned to one or two different methods of acupuncture, after studying the underlying pain mechanisms using a Multidisciplinary Pain Clinic approach and the differential spinal block (DSB). One group received acupuncture needling in the classical acupuncture points referred to as meridian loci needling (MLN) and the other group received tender area needling (TAN) with needles inserted in the dermatomal distribution of the painful areas. The responses between the two groups showed no significant difference. Results were then related to the predetermined somatopsychological basis of the individual's pain problems as classified by the DSB. A group of patinets in whom pain relief occurred upon subarachnoid injection of 0.25% procaine followed by sympathetic blockade or 0.5% procaine injection followed by hypalgesia without motor loss, also reported maximum subjective improvement in their pain level following acupuncture therapy performed at a later time. The other group of patients in whom pain persisted despite sensory and motor blockade (1% procaine) responded very poorly to acupuncture therapy. DSB was found to be complimentary to acupuncture therapy in that it facilitated patient selection for the therapy.

214: Acupuncture analgesia for chronic low back pain. Mendelson G, Kidson MA, Loh ST, Scott DF, Selwood TS, Kranz H. Clin Exp Neurol 1978;15:182-5

Preliminary findings are presented of a double-blind, crossover trial comparing the effects of traditional with placebo acupuncture in relieving chronic low back pain. 77 patients completed the study. Following initial assessment and baseline readings, patients had a 4-week course of active or placebo treatment given twice weekly. After a 4 week rest period patients received the alternate treatment, using the same time schedule. A 4 week follow-up period completed the trial. Using visual analogue scale readings as a measure of pain there was no cumulative difference in pain reduction achieved by traditional as compared with placebo acupuncture treatment. Both groups achieved a 55% overall reduction in pain level at the end of the trial, compared with initial baseline readings.

215: Mendelson G, Selwood TS, Kranz H, Loh TS, Kidson MA, Scott DS. Acupuncture treatment of chronic back pain. A double-blind placebo-controlled trial. Am J Med 1983 Jan;74(1):49-55

Acupuncture treatment of chronic low back pain was studied in a placebo-controlled double-blind crossover trial completed by 77 patients. The patients had significantly increased depression, neuroticism, and hypochondriasis scores. Initial pain levels correlated with state-anxiety, depression, pain duration, and abnormal illness behavior measures, as well as with the intake of psychotropic but not analgesic medication. Overall reduction in pain score was 26 percent for acupuncture and 22 percent for placebo treatment; the difference was not significant (p greater than 0.6). Analgesic drug intake was reduced to a similar extent in both groups. During the first phase of treatment, patients receiving acupuncture had a greater but not significantly different reduction in pain rating scores compared with those receiving placebo (t = 0.52; p greater than 0.6). This group showed significantly lower pain scores (p less than 0.05) in the second phase of the trial while receiving placebo treatment. Overall reduction in individual patient's pain score was best predicted by initial pain severity (r = 0.43; p less than 0.001) and psychotropic drug intake (r = 0.37; p less than 0.001). None of the variables tested predicted which patients would specifically respond to acupuncture or placebo.

216: ter Riet G, Kleijnen J, Knipschild P. Acupuncture and chronic pain: a criteria-based meta-analysis.

J Clin Epidemiol 1990;43(11):1191-9

Department of Epidemiology/Health Care Research, University of Limburg, Maastricht, The Netherlands.

A literature search revealed 51 controlled clinical studies on the effectiveness of acupuncture in chronic pain. These studies were reviewed using a list of 18 predefined methodological criteria. A maximum of 100 points for study design could be earned in four main categories: (a) comparability of prognosis, (b) adequate intervention, (c) adequate effect measurement and (d) data presentation. The quality of even the better studies proved to be mediocre. No study earned more than 62% of the maximum score. The results from the better studies (greater than or equal to 50% of the maximum score) are highly contradictory. The efficacy of acupuncture in the treatment of chronic pain remains doubtful.

217: Kent GP, Brondum J, Keenlyside RA, LaFazia LM, Scott HD. A large outbreak of acupuncture-associated hepatitis B. Am J Epidemiol 1988 Mar;127(3):591-8

Division of Field Services, Centers for Disease Control, Atlanta, GA 30333.

An epidemiologic investigation of an acupuncturist's practice in Rhode Island identified 35 patients who were infected with hepatitis B virus during 1984. Of 366 patients seen by the acupuncturist during 1984, 316 (86%) completed questionnaires and submitted serum for hepatitis B serology. Use of tests for immunoglobulin M antibody to hepatitis B core antigen (IgM anti-HBc) identified 17 case-patients who otherwise may have gone undetected. Thirty-four of the 35 case-patients were treated in only one of the two clinics run by the acupuncturist. Patients who received a greater number of acupuncture needles during their treatment course were more likely to have been infected; the attack rate for patients who received less than 150 needles was 9%, compared with 33% for patients who received greater than or equal to 450 needles (p less than 0.001). Attack rates were higher during a one-month period when the index case-patient was more likely to have been viremic than during any other period in 1984 (relative risk = 4.1, 95% confidence interval = 2.3-7.3). While observing the acupuncturist's technique, the investigators noted several potential mechanisms for needle contamination. This study highlights the potential for transmission of hepatitis B in situations of repeated needle use.

222: Damkot DK, Pope MH, Lord J, Frymoyer JW. The relationship between work history, work environment and low-back pain in men. Spine 1984 May-Jun;9(4):395-9

Interviews were conducted with 303 men to determine aspects of work history and working environment that are related to low-back pain. Respondents included no pain, moderate pain, and severe pain samples. Data were obtained for 150 variables including task frequencies, weights lifted, lifting postures, type of floor surface, type of chair support, pushing, pulling, and carrying activities, driving vehicles, and attributions of pain occurrence to particular situations. Univariate analyses showed difference among the three pain groups for lifting method, having had lifting instruction, stretching and reaching activities, amount of sitting and twisting in seat, pushing materials of varied weights, and contributions of pain onset. Multivariate regression analyses selected activities from (1) standing and lifting, (2) carrying, pushing, and pulling, (3) sitting, (4) driving vehicles, and (5) using vibrating equipment that jointly explained pain group variance. The significant variables from each domain were used in second-level multiple regressions to explain differences between no pain and pain, and between moderate and severe pain. Computed weights for pulling, lifting method, weight carried, reaching and stretching, chair support, number of times/day in-out of chair, and heavy vibration exposure explained 27% of variance between moderate and severe pain groups. Weights for automobile driving, number of times/day in-out of vehicle, number of lifts/day, maximum weight pulled, sitting with feet on floor, and exposure to heavy vibration explained 23% of the variance between no pain and pain groups.

225: Garg A, Moore JS. Epidemiology of low-back pain in industry. Occup Med 1992 Oct-Dec;7(4):593-608

Industrial and Systems Engineering, College of Engineering and Applied Science, University of Wisconsin, Milwaukee 53201.

Low-back pain and back injuries are of such a complex nature that any one criterion cannot be applied by itself to give a valid assessment of the risk associated with manual materials-handling jobs. There is no question that low-back pain is an extremely significant cause of disability and has a major socioeconomic impact, but many different personal and job factors are associated with the incidence and prevalence of these complaints. There is a need for ongoing systematic investigations of the multiple risk factors that may be causally related to low-back pain and may possibly be amendable to preventive interventions. Knowledge of workplace and individual risk factors is far from complete. Prospective studies are needed so that factors contributing to the development of low-back pain can be separated from factors resulting from low-back pain. It is difficult to relate low-back pain to the workplace because it occurs quite often in workers employed in sedentary occupations. However, incidence, severity, and disability are all related to the physical demands of the job. In this regard, jobs involving lifting, lowering, pushing, pulling, carrying, and holding; body movements such as frequent bending, twisting, and sudden movements; and working in bent-over postures appear to have a significant potential for producing low-back pain. A combination of lifting, bending, and twisting appears to be most hazardous. It is concluded that lifting heavy loads contributes to increased frequency and severity rates for low-back pain. This is true regardless of whether the lifting is performed over a short period or throughout the day and whether it is performed a few times per day of repetitively. If, however, such lifting is performed repetitively, the medical hazard extends beyond low-back problems to other musculoskeletal strain and sprain injuries and to fatigue-related injuries, particularly for weaker workers. In this latter regard, gender, age, anthropometry, and previous history of back pain are known to modify these risks for populations of workers. The inherent variability between workers and within any worker over time precludes the use of such factors to assign risk to any particular individual.

226: Nachemson AL. Disc pressure measurements. Spine 1981 Jan-Feb;6(1):93-7

By measurement of intradiscal pressure in vitro, the hydrostatic properties of the nucleus pulposus of normal lumbar intervertebral disc were proven. The hydrodynamic properties seem to exist also in the somewhat degenerated disc, but not in the more severely deranged ones. Intravitally-performed measurements of disc pressure over the last 20 years in more than 100 individuals have demonstrated how the load on the lumbar disc varies with the position of the subject's body and during the performance of various tasks, both in standing and in sitting. Compared with the pressure of load in the upright standing position, reclining reduces the pressure by 50-80%, while unsupported sitting increases the load by 40%, forward leaning and weight lifting by more than 100%, and the position of forward flexion and rotation by 400%. Large augmentations in pressure were also observed in subject performing various commonly prescribed strengthening exercises.

253. Schultz A, Andersson G, Ortengren R, Haderspeck K, Nachemson A. Loads on the lumbar spine. Validation of a biomechanical analysis by measurements of intradiscal pressures and myoelectric signals. J Bone Joint Surg Am 1982 Jun;64(5):713-20

We studied the validity of predictions of compressive loads on the lumbar spine and contraction forces in lumbar trunk muscles based on a biomechanical model. The predictions were validated by quantitative measurements of myoelectric activities at twelve locations on the trunk and of the pressure in the third lumbar disc. Twenty-five tasks were performed isometrically by four healthy volunteers. The model predicted that the tasks imposed mean compressive loads on the spine of as much as 2400 newtons and required contraction forces of the posterior muscles of the back of as much as 1800 newtons. Intradiscal pressures of as much as 1600 kilopascals were measured. The predicted and measured quantities were well correlated. It appears that the model adequately predicted the compressive loads on the lumbar spine and the tensions in the back muscles. Clinical Relevance: Patients with low-back disorders limit their physical activities, which indicates that loading on the spine must be a factor in those disorders. This study shows that the loads imposed on the spine by physical activities need not be measured. They can easily be calculated. This will significantly accelerate biomechanics research on low-back disorders. The calculation techniques that we validated for predicting loads on the spine can be used to calculate the loads on any skeletal structure. Those loads are largely determined not by the externally applied loads, but by the moments of those applied loads and by the moments of the weights of the body segments that the structure must support.

228: Waters TR, Putz-Anderson V, Garg A, Fine LJ. Revised NIOSH equation for the design and evaluation of manual lifting tasks. Ergonomics 1993 Jul;36(7):749-76

National Institute for Occupational Safety and Health, Cincinnati, OH 45226.

In 1985, the National Institute for Occupational Safety and Health (NIOSH) convened an ad hoc committee of experts who reviewed the current literature on lifting, recommend criteria for defining lifting capacity, and in 1991 developed a revised lifting equation. Subsequently, NIOSH developed the documentation for the equation and played a prominent role in recommending methods for interpreting the results of the equation. The 1991 equation reflects new findings and provides methods for evaluating asymmetrical lifting tasks, lifts of objects with less than optimal hand-container couplings, and also provides guidelines for a larger range of work durations and lifting frequencies than the 1981 equation. This paper provides the basis for selecting the three criteria (biomechanical, physiological, and psychophysical) that were used to define the 1991 equation, and describes the derivation of the individual components (Putz-Anderson and Waters 1991). The paper also describes the lifting index (LI), an index of relative physical stress, that can be used to identify hazardous lifting tasks. Although the 1991 equation has not been fully validated, the recommended weight limits derived from the revised equation are consistent with or lower than those generally reported in the literature. NIOSH believes that the revised 1991 lifting equation is more likely than the 1981 equation to protect most workers.

228a: Waters TR, Baron SL, Piacitelli LA, Anderson VP, Skov T, Haring-Sweeney M, Wall DK, Fine LJ.

Evaluation of the revised NIOSH lifting equation. A cross-sectional epidemiologic study. Spine 1999 Feb 15;24(4):386-94; discussion 395

National Institute for Occupational Safety and Health, Cincinnati, Ohio, USA.

STUDY DESIGN: A cross-sectional study of the 1-year prevalence of low back pain was conducted in workers employed in manual lifting jobs. OBJECTIVES: To provide epidemiologic data to determine the correlation between the prevalence of low back pain and exposure to manual lifting stressors, measured with the lifting index component of the revised lifting equation from the National Institute for Occupational Safety and Health (NIOSH). SUMMARY OF BACKGROUND DATA: The NIOSH lifting equation has been proposed as a practical, yet valid tool for assessing the risks of low back pain caused by manual lifting. To date, however, there have been few studies in which the effectiveness of the equation to identify jobs with elevated rates of low back pain has been evaluated. METHODS: Fifty jobs from four industrial sites were evaluated with the NIOSH lifting equation. A symptom and occupational history questionnaire was administered to 204 people employed in lifting jobs and 80 people employed in nonlifting jobs. Regression analysis was used to determine whether there was a correlation between the lifting index and reported low back pain. RESULTS: As the lifting index increased from 1.0 to 3.0, the odds of low back pain increased, with a peak and statistically significant odds ratio occurring in the 2 < lifting index < or = 3 category (odds ratio = 2.45). For jobs with a lifting index higher than 3.0, however, the odds ratio was lower (odds ratio = 1.45) [barely statistically between LI 2.0-3.0 but not above thus, neither monotonic nor step gradient]. CONCLUSIONS: Although low back pain is a common disorder, the lifting index appears be a useful indicator for determining the risk of low back pain caused by manual lifting.

229: Deyo RA, Diehl AK, Rosenthal M. How many days of bed rest for acute low back pain? A randomized clinical trial. N Engl J Med 1986 Oct 23;315(17):1064-70

Bed rest is usually recommended for acute low back pain. Although the optimal duration of bed rest is uncertain, a given prescription may directly affect the number of days lost from work or other activities. In a randomized trial, we compared the consequences of recommending two days of bed rest (Group I) with those of recommending seven days (Group II). The subjects were 203 walk-in patients with mechanical low back pain; 78 percent had acute pain (less than or equal to 30 days), and none had marked neurologic deficits. Follow-up data were obtained at three weeks (93 percent) and three months (88 percent). Although compliance with the recommendation of bed rest was variable, patients randomly assigned to Group I missed 45 percent fewer days of work than those assigned to Group II (3.1 vs. 5.6 days, P = 0.01), and no differences were observed in other functional, physiologic, or perceived outcomes. For many patients without neuromotor deficits, clinicians may be able to recommend two days of bed rest rather than longer periods, without any perceptible difference in clinical outcome. If widely applied, this policy might substantially reduce absenteeism from work and the resulting indirect costs of low back pain for both patients and employers.

229a: Wilkinson MJ. Does 48 hours' bed rest influence the outcome of acute low back pain? Br J Gen Pract 1995 Sep;45(398):481-4

Department of General Practice, University of Birmingham.

BACKGROUND. Bed rest is a traditional treatment for back pain, yet only in recent years has the therapeutic benefit of this been questioned. AIM. The aim of this pilot study was to ascertain whether or not 48 hours' bed rest had an effect on the outcome of acute low back pain. METHOD. The study was conducted as a randomized controlled trial to compare a prescription of 48 hours' strict bed rest with controls; the control subjects were encouraged to remain mobile and to have no daytime rest. Nine general practitioners from practices in the West Midlands recruited patients in the age range 16-60 years who presented with low back pain of less than seven days' duration, with or without pain radiation. The outcome measures assessed were: change in straight leg raise and lumbar flexion after seven days, Oswestry and Roland-Morris disability scores after seven days and 28 days, and time taken from work. RESULTS. Forty two patients were recruited: 20 were allocated to bed rest and 22 as controls. Compared with the bed rest group the control group had statistically better Roland-Morris scores at day seven (P < 0.05) but not at day 28. At day seven, there were no statistically significant differences between groups in straight leg raise or lumbar flexion measurements although the control group had a better mean lumbar flexion than the bed rest group. The improvement in disability scores at day seven compared with day one was similar for the two groups but more of the control group had fully recovered (defined as scores of one or zero on the Roland-Morris disability scale and five or less on the Oswestry disability scale) by day seven. Remaining mobile did not appear to cause any adverse effects. The number of days lost from work in both groups was equal. A large number of self-remedies and physical therapies were recorded by subjects from both groups. CONCLUSION. The results of this pilot study did not indicate whether bed rest or remaining mobile was superior for the treatment of acute low back pain; however, the study sample was small. Subjects in the control group possibly fared better as they appeared to have better lumbar flexion at day seven. It appears that 48 hours' bed rest cannot be recommended for the treatment of acute low back pain on the basis of this small study. Large-scale definitive trials are required to detect clinically significant differences.

230: Gilbert JR, Taylor DW, Hildebrand A, Evans C. Clinical trial of common treatments for low back pain in family practice. Br Med J (Clin Res Ed) 1985 Sep 21;291(6498):791-4

The results of a multicentered randomised clinical trial are reported of bed rest and of a physiotherapy and education programme for patients who presented in family practice with an acute episode of low back pain. No beneficial effect of either treatment was observed on several clinical outcome measures, including straight leg raising, lumbar flexion, activities of daily living, and pain. In fact the results favoured early mobilisation over bed rest and suggested that the physiotherapy and education programme was doing more harm than good. Moreover, additional analyses, which focused on clinically interesting patient subgroups, discovered no subset of patients who benefited from either of the treatments under study. Having failed to identify any clinically important benefits, or other explanations for these negative results, we can only conclude that family doctors have little reason to prescribe either bed rest or isometric exercises to patients who suffer from low back pain.

234: Davies JE, Gibson T, Tester L. The value of exercises in the treatment of low back pain. Rheumatol Rehabil 1979 Nov;18(4):243-7

The results of treatment with short-wave diathermy were compared with those achieved by short-wave diathermy combined with back extension or lumbar isometric flexion exercises in 43 patients with back pain. Subjects were relatively young and normally engaged in sporting activities. Marginally more patients improved amongst those receiving extension exercises. Significant reduction of pain and increase of spinal flexion occurred with each treatment and the periods taken to resume work or sport were similar in each group. Neither exercise regime appeared to have a major influence on recovery. Isometric flexion exercises did not seem to be more beneficial for those with a prominent lumbar lordosis.

235: Donelson R, Grant W, Kamps C, Medcalf R. Pain response to sagittal end-range spinal motion. A prospective, randomized, multicentered trial. Spine 1991 Jun;16(6 Suppl):S206-12

Department of Orthopedic Surgery, State University of New York, Syracuse.

This article reports a prospective, randomized, multicentered study documenting changes in the intensity and location of low-back and referred pain to repeated end-range lumbar flexion and extension movements performed first while standing and then while recumbent during a single clinical patient evaluation. Significant and rapid changes in central and distal pain intensity and location of peripheral pain resulted from the performance of these movements. For the mean in both protocols, regardless of the order of spinal movements, end-range extension significantly decreased central and distal pain intensity and centralized referred pain. Flexion spinal movements, however, significantly increased mean central and distal pain intensity and peripheralized the pain. Forty percent of individual subjects had a clear preference for extension and 7% a clear preference for flexion.

236: Gundewall B, Liljeqvist M, Hansson T. Primary prevention of back symptoms and absence from work. A prospective randomized study among hospital employees. Spine 1993 Apr;18(5):587-94

Centrumhlsan i Goteborg AB, Askim, Sweden.

The personnel at a geriatric hospital were randomized into two groups. One group was allowed to exercise during working hours to improve back muscle strength, endurance, and coordination. The other group did not participate in the exercise program and received no further advice or information. After 13 months, the training group had increased back muscle strength. One subject had been absent from work 28 days in the training group whereas 12 subjects had been absent 155 days from work because of low back pain in the control group (P < 0.004). The back pain complaints and intensity of back pain in the training group also decreased in a statistically significant way. Every hour spent by the physiotherapist on the training group reduced the work absence among the participants by 1.3 days, resulting in a cost/benefit ratio greater than 10.

236a: Malmivaara A, Hakkinen U, Aro T, Heinrichs ML, Koskenniemi L, Kuosma E, Lappi S, Paloheimo R, Servo C, Vaaranen V, et al. The treatment of acute low back pain--bed rest, (passive) exercises, or ordinary activity? N Engl J Med 1995 Feb 9;332(6):351-5

Department of Occupational Medicine, Finnish Institute of Occupational Health, Helsinki.

BACKGROUND. Bed rest and (passive) back-extension exercises are often prescribed for patients with acute low back pain, but the effectiveness of these two competing treatments remains controversial. METHODS. We conducted a controlled trial among employees of the city of Helsinki, Finland, who presented to an occupational health care center with acute, nonspecific low back pain. The patients were randomly assigned to one of three treatments: bed rest for two days (67 patients), (passive) back-mobilizing exercises (52 patients), or the continuation of ordinary activities as tolerated (the control group; 67 patients). Outcomes and costs were assessed after 3 and 12 weeks. RESULTS. After 3 and 12 weeks, the patients in the control group had better recovery than those prescribed either bed rest or (passive) exercises. There were statistically significant differences favoring the control group in the duration of pain, pain intensity, lumbar flexion, ability to work as measured subjectively, the Oswestry back-disability index, and number of days absent from work. Recovery was slowest among the patients assigned to bed rest. The overall costs of care did not differ significantly among the three groups. CONCLUSIONS. Among patients with acute low back pain, continuing ordinary activities within the limits permitted by the pain leads to more rapid recovery than either bed rest or (passive) back-mobilizing exercises.

236b: Indahl A, Haldorsen EH, Holm S, Reikeras O, Ursin H. Five-year follow-up study of a controlled clinical trial using light mobilization and an informative approach to low back pain. Spine 1998 Dec 1;23(23):2625-30

Spine Clinic, Ostfold Central Hospital, Fredrikstad, Norway. aage.indahl@medisin.uio.no

STUDY DESIGN: A controlled clinical trial. OBJECTIVES: To examine the long-term effect of an informative approach to low back pain. SUMMARY OF BACKGROUND DATA: In management and prevention of low back pain, back school based on an ergonomic approach have played in important role. The effect of such informative interventions is not clear. METHODS: A 5-year follow-up study was done on patients included in a previous study. The outcome was measured by return to work or still on sick leave. The patients were allocated to an intervention group (n = 245) and a control group (n = 244). Only the intervention group was called in for examination and intervention and answered a battery of tests for psychological and health factors. The intervention apart from the clinical examination consisted of education in an "mini back school." The program was based on a new medical model for low back pain. RESULTS: Forty-seven (19%) of the patients in the intervention group, compared with 84 patients (34%) in the control group, were still on sick leave after 5 years (P < 0.001). There were fewer recurrences of sick leave (P < 0.03) in the intervention group than in the control group. Based on Internal Health Locus of Control, number of children, and income, 75% were correctly classified as nonreturners in the intervention group. CONCLUSIONS: This study indicates that subchronic low back pain may be managed successfully with an approach that includes clinical examination combined with information for patients about the nature of the problem, provided in a manner designed to reduce fear and give them reason to resume light activity.

236b1: Indahl A, Velund L, Reikeraas O. Good prognosis for low back pain when left untampered. A randomized clinical trial. Spine 1995 Feb 15;20(4):473-7

Oestfold Central Hospital, Fredrikstad, Norway.

OBJECTIVE. This randomized clinical trial was designed to determine the effect of treating low back pain as a benign, self limiting condition by light normal activity. METHODS. Patients on sickness leave from work for more than 8 weeks were randomized into two groups: intervention (n = 463) and control (n = 512). Those in the intervention group were examined, provided information, and given instruction. Outcome was measured by return or failure to return to work (still on sickness leave). RESULTS. Survival analysis showed a highly significant (P = 0.000) reduction in sickness leave in the intervention group as compared with the control group. At 200 days 60% were still on sickness leave in the control group vs. 30% in the intervention group. A multivariate analysis with age, sex, and treatment as cofactors showed that sex had no effect on length of sickness leave and that treatment retained its effect when adjusting for differences in age composition. CONCLUSION. This study indicates that low back pain treated as a benign, self limiting condition recommended to light mobilization gives superior results as compared to treatment within a conventional medical system.

236c. Burton AK, Waddell G, Tillotson KM, Summerton N. Information and advice to patients with back pain can have a positive effect. A randomized controlled trial of a novel educational booklet in primary care. Spine 1999 Dec 1;24(23):2484-91

Spinal Research Unit, University of Huddersfield, Queensgate, United Kingdom. kburton@cix.co.uk

STUDY DESIGN: A double-blind, randomized controlled trial of a novel educational booklet compared with a traditional booklet for patients seeking treatment in primary care for acute or recurrent low back pain. OBJECTIVE: To test the impact of a novel educational booklet on patients' beliefs about back pain and functional outcome. SUMMARY OF BACKGROUND DATA: The information and advice that health professionals give to patients may be important in health care intervention, but there is little scientific evidence of their effectiveness. A novel patient educational booklet, The Back Book, has been developed to provide evidence-based information and advice consistent with current clinical guidelines. METHODS: One hundred sixty-two patients were given either the experimental booklet or a traditional booklet. The main outcomes studied were fear-avoidance beliefs about physical activity, beliefs about the inevitable consequences of back trouble, the Roland Disability Questionnaire, and visual analogue pain scales. Postal follow-up response at 1 year after initial treatment was 78%. RESULTS: Patients receiving the experimental booklet showed a statistically significant greater early improvement in beliefs which was maintained at 1 year. A greater proportion of patients with an initially high fear-avoidance beliefs score who received the experimental booklet had clinically important improvement in fear-avoidance beliefs about physical activity at 2 weeks, followed by a clinically important improvement in the Roland Disability Questionnaire score at 3 months. There was no effect on pain. CONCLUSION: This trial shows that carefully selected and presented information and advice about back pain can have a positive effect on patients' beliefs and clinical outcomes, and suggests that a study of clinically important effects in individual patients may provide further insights into the management of low back pain.

236e. Buchbinder R, Jolley D, Wyatt M, Effect of Media Campaign on Back Pain Beliefs and Its Potential Influence on Management of Low Back Pain in General Practice SPINE 2001 Dec 1:26(23)2535-2542

237: Kellett KM, Kellett DA, Nordholm LA. Effects of an exercise program on sick leave due to back pain. Phys Ther 1991 Apr;71(4):283-91; discussion 291-3

Department of Physiotherapy, Health Centre, Tidaholm, Sweden.

The purposes of this study were to evaluate the effect of a weekly exercise program on short-term sick leave (less than 50 days) attributable to back pain and to determine whether changes in absenteeism were related to changes in cardiovascular fitness. Subjects were randomly assigned to an exercise group (n = 58) and a control group (n = 53). Sick leave attributable to back pain was determined in the intervention period of 1 1/2 years and a comparable 1 1/2-year period prior to the study. In the exercise group, the number of episodes of back pain and the number of sick-leave days attributable to back pain in the intervention period decreased by over 50%. Absenteeism attributable to back pain increased in the control group. The decrease in sick leave in the exercise group was not accompanied by any change in cardiovascular fitness. Suggestions for establishing exercise programs are given.

240: McCain GA, Bell DA, Mai FM, Halliday PD. A controlled study of the effects of a supervised cardiovascular fitness training program on the manifestations of primary fibromyalgia. Arthritis Rheum 1988 Sep;31(9):1135-41

Division of Rheumatology, University of Western Ontario, London, Canada.

Forty-two patients with primary fibromyalgia were randomized into a 20-week program consisting of either cardiovascular fitness (CVR) training or simple flexibility exercises (FLEX) that did not lead to enhanced cardiovascular fitness. Patients were supervised by the same medical fitness instructors. Patients in neither group had contact with members of the other group, and were blinded as to the exercise taught to the alternative group. Groups met for 60 minutes 3 times each week. The compliance rate was 90%. Thirty-eight patients completed the study (18 with CVR training and 20 with FLEX). Blind assessments (standardized in preliminary trials to achieve acceptable inter-rater agreement) were performed by the same 2 examiners. After 20 weeks, patients receiving CVR training showed significantly improved cardiovascular fitness scores compared with those receiving FLEX training (t[35] = -4.22, P less than 0.003). Logistic regression analysis showed clinically and statistically significant improvements in pain threshold scores, which were measured directly over fibrositic tender points, in patients undergoing CVR (t[35] = 2.21, P less than 0.04). There was also a trend toward improvement in pain scores (visual analog scale) in the CVR group, but this did not reach statistical significance. There was no improvement in the percentage of body area affected by fibrositic symptoms or the number of nights per week or hours per night of disturbed sleep (self-report inventories). However, compared with the FLEX group, the CVR-trained patients improved significantly in both patient and physician global assessment scores.(ABSTRACT TRUNCATED AT 250 WORDS)

241: Reilly K, Lovejoy B, Williams R, Roth H. Differences between a supervised and independent strength and conditioning program with chronic low back syndromes. J Occup Med 1989 Jun;31(6):547-50

Rehabilitation and Sports Performance Center, Denver, CO 80237.

The purpose of this study was to evaluate changes in physiologic parameters seen in a group of patients with chronic low back syndrome assigned to supervised and independent strength and conditioning programs. Forty patients with chronic low back syndrome were assigned either to a control group (independent exercise) or to an experimental group (supervised exercise). All subjects underwent pre-testing for aerobic fitness, strength and responses to visual analog pain rating scales. Twenty control subjects were given predesigned exercise programs and told to exercise four times per week for 6 months. Twenty experimental subjects were given predesigned exercise programs but were monitored by a strength and conditioning specialist for the same period. Statistically significant results were seen for increases in aerobic fitness and strength, decreases in reported pain, and percent body fat in the experimental group. Since the experimental group completed 90.75 sessions out of 96, compared with 31.95 for the control group, it could be concluded that supervision increases chances for compliance and success as measured by these parameters.

242: Turner JA, Clancy S, McQuade KJ, Cardenas DD. Effectiveness of behavioral therapy for chronic low back pain: a component analysis. J Consult Clin Psychol 1990 Oct;58(5):573-9

School of Medicine, Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle 98195.

The effects of outpatient group behavioral therapy including aerobic exercise (BE), behavioral therapy only (B), and aerobic exercise only (E) on pain and physical and psychosocial disability were evaluated and compared in a group of mildly disabled chronic low-back-pain patients. Ninety-six Ss were randomly assigned to the 3 treatments and a waiting-list control (WL) condition and assessed on a variety of patient self-report, spouse-rated, and direct observational measures at pretreatment, posttreatment, and 6- and 12-month follow-ups. Patients in the BE condition, but not the B or E conditions, improved significantly more pretreatment to posttreatment than did WL patients on the patient self-report and observer-rated measures. At both follow-ups, all 3 treatment groups remained significantly improved from pretreatment, with no significant differences among treatments.

243: Zylbergold RS, Piper MC. Lumbar disc disease: comparative analysis of physical therapy treatments. Arch Phys Med Rehabil 1981 Apr;62(4):176-9

A randomized clinical trial was conducted to evaluate the efficacy of 3 physical therapy approaches--lumbar flexion exercise, manual therapy, and home care--in the treatment of lumbar disc disease. Twenty-eight patients were assigned to 1 of 3 treatment groups and were shown to be similar in age, sex, and prescores on 4 of the 5 outcome measures. With the exception of the home care patients, each patient received the appropriate treatment twice a week for a 1-month period. No statistically significant differences in measurements of pain, forward, right-side, and left-side flexion, or functional activity between the 3 groups were observed.

246: Fordyce WE, Brockway JA, Bergman JA, Spengler D. Acute back pain: a control-group comparison of behavioral vs traditional management methods. J Behav Med 1986 Apr;9(2):127-40

Back-pain patients with onset in the preceding 1-10 days and comparable on a back examination were randomly assigned to traditional management (A regimen) and behavioral treatment methods (B regimen). Patients were compared at 6 weeks and 9-12 months on a set of "Sick/Well" scores derived from patient reported vocational status (V), health-care utilization (HCU), claimed impairment (CI), and pain drawings (D) and on two measures of activity level. No differences were found at 6 weeks, but at 9-12 months, A-group S's were more "sick." No A/B differences were found on activity-level measures. Group A S's showed significant increases in claimed impairment from preonset to follow-up, whereas Group B S's had returned at follow-up to preonset levels.

247: Nachemson A. Towards a better understanding of low-back pain: a review of the mechanics of the lumbar disc. Rheumatol Rehabil 1975 Aug;14(3):129-43

By measurement of intradiscal pressure in vitro, the hydrostatic properties of the nucleus pulposus of normal lumbar intervertebral disc was established. The stress distribution within normal discs subjected to vertical load was also explained, demonstrating the high tangential strains occurring in the posterior part of the annulus fibrosus. Intravitally performed measurements of disc pressure have demonstrated how the load on the lumbar disc varies according to the position of the subject's body. Compared to the pressure or load in the upright standing position, reclining reduces the pressure by 70%, while unsupported sitting increases the load by 40% and forward leaning and weight lifting by more than 100%. Similar relatively large augmentations of the load were observed in subjects performing various commonly used muscle-strengthening exercises. Measurement of intradiscal pressure is instrumental in explaining, from a mechanical point, the occurrence of posterior ruptures in the lumbar discs, and provides a basis for the rational treatment of patients with low-back pain in so far as these exhibit increase of pain on increased mechanical loads. For the majority of patients with low-back pain, the cause is unknown, although most evidence so far presented links the lumbar intervertebral disc to the pain syndromes. Results of recent studies have shown that both chemical and mechanical factors are probably of importance. So far we cannot successfully treat the chemical part of the disc syndrome. Since all our patients exhibit more pain when the spine is mechanically loaded, knowledge gained from intravital disc-pressure measurements provides a basis for successfully treating the mechanical part of the condition. Since none of the frequently prescribed and more spectacular remedies has ever been proved statistically superior to any of the others, it is most fair to our patients and to ourselves to use simpler, less expensive, and less dangerous programmes, such as bed-rest, administration of salicylates, and proper ergonomic advice. Based on a scientific approach, the low-back-pain school is intended to help the patient to be able to cope with these back troubles, to avoid excess therapy, and to decrease the cost both for the individual and for Society.

250: Nordin M, Ortengren R, Andersson GB. Measurements of trunk movements during work. Spine 1984 Jul-Aug;9(5):465-9

To study spinal movements during work, an instrument that measured angles and angle changes in relation to a vertical plane was adapted to continuously measure forward flexion of the trunk. The instrument, which is battery-powered and worn on the back, registers the amount of flexion and its distribution over time during a work cycle by recording the time spent in each of five 18 degrees intervals between 0 degrees and 90 degrees. Also the number of times that the angle of flexion changed from one interval to another is recorded. A total of 43 subjects from three occupations--dentistry, nurses' aide work, and warehouse work--were each tested during a 60 minute work cycle. On the average, the dentists spent most of the time (52.2 minutes) in a semi-flexed position not exceeding 36 degrees and performed eight deep forward flexions (greater than 73 degrees). The nurses' aides spent one-half of the work cycle (34.4 minutes) in an upright position (0-18 degrees) and performed 70 deep forward flexions. The warehouse workers spent less than one-half of the work cycle in an upright position (27.5 minutes) and performed 153 deep forward flexions that nearly always were associated with lifting.

251: Sachs BL, Ahmad SS, LaCroix M, Olimpio D, Heath R, David JA, Scala AD. Objective assessment for exercise treatment on the B-200 isostation as part of work tolerance rehabilitation. A random prospective blind evaluation with comparison control population. Spine 1994 Jan 1;19(1):49-52

Department of Orthopaedics, Tufts University Medical School, New England Medical Center Hospitals, Boston, Massachusetts.

The purpose of this study was to assess repeated exercise on the B-200 Isostation as part of rehabilitation work tolerance for nonsurgical patients with lumbar spine disorders. For a consecutive 7-month period, treatment subjects were randomly assigned according to birth date for participation in two groups: a standard work tolerance program only or standard work tolerance program plus inclusion of exercise on the B-200 Isostation. Each patient had similar referral diagnosis requiring conservative treatment. Treatment groups were compared with a control population of volunteers who had neither back pain nor known underlying spinal pathology. All study patients had objective measurement of range of motion, isometric strength, and velocity of motion, on the B-200 Isostation before treatment and at follow-up 3 weeks after treatment. The data showed no significant difference of percent improvement when comparing patients in either of the randomized assigned treatment groups. There was a higher percentage of improvement for each treatment group as compared with the control individuals, however. Based on our study using the B-200 Isostation, there is little objective justification for including exercise on the B-200 dynametric Isostation as part of the rehabilitation routine for improvement of functional physical capacity.

253: Schultz A, Andersson G, Ortengren R, Haderspeck K, Nachemson A. Loads on the lumbar spine. Validation of a biomechanical analysis by measurements of intradiscal pressures and myoelectric signals. J Bone Joint Surg Am 1982 Jun;64(5):713-20

We studied the validity of predictions of compressive loads on the lumbar spine and contraction forces in lumbar trunk muscles based on a biomechanical model. The predictions were validated by quantitative measurements of myoelectric activities at twelve locations on the trunk and of the pressure in the third lumbar disc. Twenty-five tasks were performed isometrically by four healthy volunteers. The model predicted that the tasks imposed mean compressive loads on the spine of as much as 2400 newtons and required contraction forces of the posterior muscles of the back of as much as 1800 newtons. Intradiscal pressures of as much as 1600 kilopascals were measured. The predicted and measured quantities were well correlated. It appears that the model adequately predicted the compressive loads on the lumbar spine and the tensions in the back muscles. Clinical Relevance: Patients with low-back disorders limit their physical activities, which indicates that loading on the spine must be a factor in those disorders. This study shows that the loads imposed on the spine by physical activities need not be measured. They can easily be calculated. This will significantly accelerate biomechanics research on low-back disorders. The calculation techniques that we validated for predicting loads on the spine can be used to calculate the loads on any skeletal structure. Those loads are largely determined not by the externally applied loads, but by the moments of those applied loads and by the moments of the weights of the body segments that the structure must support.

255: Arena JG, Sherman RA, Bruno GM, Young TR. Electromyographic recordings of low back pain subjects and non-pain controls in six different positions: effect of pain levels. Pain 1991 Apr;45(1):23-8

Biofeedback and Psychophysiological Disorders Clinic, Veterans Affairs Medical Center, Augusta, GA 30910.

Surface electromyographic (EMG) activity recordings of bilateral paraspinal muscle tension were measured twice on 20 non-pain controls and on 46 low back pain subjects (21 individuals with intervertebral disk disorders and 25 subjects with unspecified musculoskeletal backache) during 6 positions: standing, bending from the waist, rising, sitting with back unsupported, sitting with back supported, and prone. Back pain subjects were measured during both low pain and high pain states. Results revealed a non-significant trend for all subjects, regardless of diagnosis, to have higher paraspinal muscle tension levels on the second (or high pain) assessment. A significant diagnosis by position interaction was observed which was similar to the interaction in our previous study which employed only a single measurement session. Analysis of simple main effects revealed this to be due to control subjects during the standing position having lower EMG levels than the back pain groups, and intervertebral disk disorder subjects having higher EMG levels than the other groups during the supported sitting position. As in our previous study, diagnosis was found to be a clinically significant factor, in that controls had much fewer clinically abnormal readings than back pain patients. The lack of a significant effect for pain state is congruent with findings in the headache literature. The importance of clearly defined diagnostic categories in low back pain research and the utility of measuring subjects in various positions is discussed, as are possible explanations for lack of significant pain state findings.

257: Khatri BO, Baruah J, McQuillen MP. Correlation of electromyography with computed tomography in evaluation of lower back pain. Arch Neurol 1984 Jun;41(6):594-7

High-resolution computed tomography (CT) of the lumbar spine in 80 consecutive patients with lower back pain was correlated with electromyography (EMG) and with the clinical outcome at one-year follow-up. Forty-two patients had abnormal EMG findings that could be explained on the basis of anatomical defect(s) seen on CT. Nine had normal CT scans but abnormal EMGs, and five patients had normal EMGs but abnormal CT scans. Thirteen of the 80 patients were further investigated with myelography, 22 patients underwent surgical exploration, and the remainder received conservative therapy. In the majority of cases, surgery confirmed the abnormal CT and EMG findings; in some instances, however, myelography and/or surgery confirmed the abnormality only at the level demonstrated on EMG. The CT and EMG often agree. However, an abnormal EMG seems to correlate better with the demonstrated course of radiculopathy than CT.

258: Sihvonen T, Partanen J, Hanninen O, Soimakallio S. Electric behavior of low back muscles during lumbar pelvic rhythm in low back pain patients and healthy controls. Arch Phys Med Rehabil 1991 Dec;72(13):1080-7

Department of Clinical Neurophysiology, University Central Hospital of Kuopio, Finland.

The functioning of low back muscles of back pain patients during flexion and reextension has not been properly investigated. In this study, we analyzed rectified, averaged electric activity (RMS EMG) and corresponding raw intramuscular (IM) EMG from lumbar paraspinal muscles to quantify the activity level during simple bending cycles in 87 back pain patients compared to 25 able-bodied controls. The results: All functional phases seen in raw IM EMG were also shown in surface RMS EMG. Surface RMS EMG pattern seems to yield more information from activity level than IM EMG pattern. The RMS EMG patterns of back pain patients differed from those of controls as follows: (1) There was clearly noticeable activity during standing in back pain patients. (2) There was only a partial decrease of EMG activity after flexion in back pain patients with current pain. (3) The ratio of mean reached at maximal activity level during extension and flexion was less in patients (1.8, SD = 0.5, p less than .001) than able-bodied controls (3.2, SD = 0.8). (4) Segmental differences were observed in IM EMG activities in patients having hypermobility in bending x-ray. (5) Large peak potentials occurred during movements in patients having segmental hypermobility. The results indicate that averaged surface recording is a valuable tool in the investigation of dynamic spine functions in back pain patients.

260: Young A, Getty J, Jackson A, Kirwan E, Sullivan M, Parry CW. Variations in the pattern of muscle innervation by the L5 and S1 nerve roots. Spine 1983 Sep;8(6):616-24

Evidence based on electrical studies is presented for the standard and anomalous patterns of innervation of muscles supplied by the fifth lumbar and first sacral nerve roots. Although considerable controversy still exists, previous work in this field suggests that the L5 nerve root supplies tibialis anterior, extensor hallucis longus, extensor digitorum brevis, and the lateral head of gastrocnemius, while the S1 nerve root innervates the medial head of gastrocnemius, soleus, and abductor hallucis. In order to confirm the reliability of this data, the L5 and S1 nerve roots of 50 patients were electrically stimulated during surgery, and distally evoked responses in the relevant muscles were recorded, using surface electrodes. The results confirm the essential reliability of the proposed table of segmental innervation and also demonstrate that most muscles have a dual innervation, with one nerve root being dominant. However, eight patients (16%) exhibited a marked departure from the normal pattern. For example, it is clear that on occasion the extensor digitorum brevis and the lateral head of gastrocnemius can be supplied by S1 and the soleus and medial head of gastrocnemius can be supplied by L5. In a prospective study of 100 patients presenting with clinical evidence of lumbosacral nerve root entrapment, the level of nerve root involvement, as predicted by electromyography, was compared with the operative findings. Correct preoperative nerve root localization was achieved in 84%.(ABSTRACT TRUNCATED AT 250 WORDS)

261: Ahern DK, Follick MJ, Council JR, Laser-Wolston N, Litchman H. Comparison of lumbar paravertebral EMG patterns in chronic low back pain patients and non-patient controls. Pain 1988 Aug;34(2):153-60

Miriam Hospital, Brown University Program in Medicine, Providence, RI 02906.

According to myogenic models that relate abnormal EMG patterns to the experience of pain, lumbar paravertebral muscle activity has been considered to play an important role in chronic low back pain. In the present study, 40 chronic low back pain patients and 40 matched non-patient controls were compared on lumbar paravertebral EMG during mechanically stabilized static and dynamic postures. Differences between groups in lumbar curvature and spinal range of motion were determined using a dual goniometer technique. Although the two groups did not differ on absolute levels of EMG during quiet standing, significant differences were found for EMG patterns during dynamic postures. In addition, most patients did not show the flexion-relaxation response or the expected pattern of EMG responses during trunk rotation, most likely because of restricted range of motion and/or compensatory posturing. These findings provide support for the biomechanical model of chronic pain and indicate the need for further research pertaining to pain behavior and movement-related lumbar muscle activity.

262. Esdaile JM, Rosenthall L, Terkeltaub R, Kloiber R. Prospective evaluation of sacroiliac scintigraphy in chronic inflammatory back pain. Arthritis Rheum. 1980 Sep;23(9):998-1003.

To assess the usefulness in screening for sacroiliitis of a wide band profile cut which included the entire sacroiliac (SI) joint, 34 patients with chronic inflammatory back pain (IBP) underwent sacroiliac joint scintigraphy with 99mTc-methylene diphosphonate while receiving no antiinflammatory therapy. The sacroiliac joint to sacrum (SIJ/S) ratios in those with back pain differed significantly from the ratios of an age-matched control group. However, 12 of the 34 patients with inflammatory back pain had normal or equivocal sacroiliac radiographs and 4 of 12 had normal SIJ/S ratios. All 4 were HLA-B27 positive, had diminished lumbar movement, and required antiinflammatory medication; 2 had diminished chest expansion; 1 has developed iritis. We conclude that this technique is not a reliable screening procedure. Therapy with antiinflammatory drugs was associated with a significant decrease in the SIJ/S ratios in 19 of the 34 who were reimaged.

263: Lowe J, Schachner E, Hirschberg E, Shapiro Y, Libson E Significance of bone scintigraphy in symptomatic spondylolysis. Spine 1984 Sep;9(6):653-5

In a prospective study, the authors evaluated the usefulness of bone scintigraphy in the work-up of young military personnel with lumbar spondylolysis and persistent low back pain. Ten out of 23 spondylolytic individuals with a recent history of low back pain had positive scintigrams, and none of a group of painless spondylolytic individuals had positive scans. We believe these results indicate that bone scintigraphy is of value in determining whether a spondylolysis in a young individual can be attributed to recent physical exertion or a specific recent traumatic incident.

264: Miron SD, Khan MA, Wiesen EJ, Kushner I, Bellon EM. The value of quantitative sacroiliac scintigraphy in detection of sacroiliitis. Clin Rheumatol 1983 Dec;2(4):407-14

To evaluate clinical usefulness of quantitative sacroiliac scintigraphy (QSS) in detecting sacroiliitis, we used a modified, pixel by pixel technique for calculating sacroiliac joint/sacrum uptake ratios (sacroiliac joint index - SII). We studied 90 controls, 18 selected patients with active sacroiliitis, 2 ankylosing spondylitis patients with completely ankylosed sacroiliac joints, 14 patients with nonspecific low back pain and 5 patients with rheumatoid arthritis. In the controls, we found that the SII decreases with increasing age (P less than 0.001) and is higher in males than in females (P less than 0.005). In the patients with active sacroiliitis, 9 out of 14 older than 30 had an abnormal SII; 3 of these patients showed no radiographic or CT abnormalities of the sacroiliac joints. None of the 4 patients with sacroiliitis under 30 years of age had values which fell out of the normal range for their age and sex. Only 1 of the 14 patients with non-inflammatory low back pain had an abnormally high SII. A borderline SII was found in 1 of the 5 patients with rheumatoid arthritis. QSS may be useful in detecting active sacroiliitis, sometimes even before the occurrence of radiologic abnormalities. However, because of its low sensitivity, its clinical usefulness is limited, especially in patients under 30 years of age.

265: Schutte HE, Park WM. The diagnostic value of bone scintigraphy in patients with low back pain. Skeletal Radiol 1983;10(1):1-4

Bone scintigraphy has been studied in two groups of patients presenting with low back pain. In one group of 38 patients suffering "nonspecific" back pain, bone scintigraphy and laboratory findings were negative in 24. There were abnormal laboratory findings in all of the remaining 14 and 7 had positive bone scans indicative of clinically significant disease. Selection of patients for bone scintigraphy in this group should therefore be influenced by abnormal laboratory findings and elevation of the erythrocyte sedimentation rate in particular. By comparison, the bone scans were reviewed from another group of patients suffering previously known malignancy. Out of 138 patients, nearly 40% showed a positive bone scan due to subsequently proven metastasis. Bone scintigraphy was positive in a further 14% as a result of osteoporotic rib fracture and vertebral body collapse. In half of these, it was not possible to exclude malignancy by scintigraphy. The present findings indicate that bone scintigraphy is not a useful procedure in patients with long-standing low back pain who have normal radiographs and normal laboratory findings.

266: Whalen JL, Brown ML, McLeod R, Fitzgerald RH Jr. Limitations of indium leukocyte imaging for the diagnosis of spine infections. Spine 1991 Feb;16(2):193-7

Mayo Clinic and Mayo Foundation, Rochester, Minnesota.

The usefulness of indium-111 white blood cell (WBC) scintigraphy in the detection of spine sepsis was studied in 22 patients who had open or percutaneous biopsies for microbiologic diagnosis. The indium images in 18 patients with vertebral infection were falsely negative in 15 (83%) and truly positive in 3 (17%). All four patients with negative cultures and histology had true-negative scans. The indium-111 WBC imaging results yielded a sensitivity of 17%, a specificity of 100%, and an accuracy rate of 31%. Prior antibiotic therapy was correlated with a high incidence of false-negative scans and photon-deficient indium-111 WBC uptake. The usefulness of indium-111 WBC scintigraphy for the diagnosis of vertebral infection may be limited to those patients who have not been treated with antibiotics previously.

267: Mills GH, Davies GK, Getty CJ, Conway J. The evaluation of liquid crystal thermography in the investigation of nerve root compression due to lumbosacral lateral spinal stenosis. Spine 1986 Jun;11(5):427-32

The role of liquid crystal thermography (LCT) in the investigation of nerve root compression due to lumbosacral lateral spinal stenosis was evaluated using a quantitative analysis technique. In 28 healthy volunteers, normal lower limb dermatomal asymmetry was found to follow a Gaussian distribution, with a normal range of less than 1.0 degree for the lower limbs and less than 1.9 degrees for the feet. The results of LCT from a patient group were compared with those from other investigations, with the following results: clinical assessment (107 patients), 53% agreement; myelography (60 patients), 45% agreement; computerized tomography (35 patients), 46% agreement; electromyography (27 patients), 41% agreement; and surgical findings (19 patients), 53% agreement. Each method of investigation was compared against the surgeon's final overall assessment. Clinical assessment agreed in 76%, myelography in 71%, computerized tomography in 71%, and electromyography in 70%. However, agreement could be demonstrated in only 48% of cases using LCT; therefore, it would appear that LCT is by far the least reliable of these techniques in the diagnosis of nerve root compression.

268: Hoffman RM, Kent DL, Deyo RA. Diagnostic accuracy and clinical utility of thermography for lumbar radiculopathy. A meta-analysis. Spine 1991 Jun;16(6):623-8

Medical Service, Seattle Veterans Affairs Medical Center, Washington.

The role of thermography for diagnosing lumbar radiculopathy was evaluated by literature review and meta-analysis. From 81 relevant citations, 28 studies could be analyzed for diagnostic-accuracy data (sensitivity and specificity) and method. Diagnostic-accuracy data varied significantly between studies; therefore meaningful pooled summary statistics could not be reported. Twenty-seven studies had major methodologic flaws including biased test interpretations, faulty cohort assembly, poor clinical descriptions, and small sample size. The only study of reasonably high quality found no discriminant value for liquid-crystal thermography. The role of thermography remains unclear. Rigorous clinical research is required to establish its diagnostic accuracy and clinical utility. Thermography cannot be recommended currently for routine clinical use in evaluating low-back pain.

269: Chafetz N, Wexler CE, Kaiser JA. Neuromuscular thermography of the lumbar spine with CT correlation. Spine 1988 Aug;13(8):922-5

Department of Radiology, University of California San Francisco.

Fifteen asymptomatic volunteers and 19 patients with current CT (GE 8800 CT/T) scans demonstrating either thecal sac contour distortion or nerve root displacement from disc rupture or spinal stenosis of the L4-L5 or L5-S1 levels judged to be at least moderate in severity underwent lumbar thermography. All patients were studied with an infrared telethermographic unit (AGA model 720M) employing the technical standards recommended by the Academy of Neuromuscular Thermography. The thermographic exams were interpreted independently and in a blind fashion by two radiologists. Of the 15 exams of asymptomatic patients, six were interpreted as positive and consistent with nerve fiber irritation. Of the 19 exams of patients with demonstrated CT abnormalities, all had positive thermograms for nerve fiber irritation (specificity 60%, sensitivity 100%). It is concluded that lumbar thermography is a sensitive examination for detecting those patients who will demonstrate lumbar spinal CT abnormalities and should play an important role in the diagnostic screening of low-back pain syndrome patients.

270: Harper CM Jr, Low PA, Fealey RD, Chelimsky TC, Proper CJ, Gillen DA. Utility of thermography in the diagnosis of lumbosacral radiculopathy. Neurology 1991 Jul;41(7):1010-4

Department of Neurology, Mayo Clinic, Rochester, MN 55905.

We performed infrared telethermography in 55 patients with the clinical diagnosis of lumbosacral radiculopathy and in 37 normal controls. Five readers interpreted the thermograms in a blinded fashion. A moderate degree of agreement was noted in tests of intraobserver and interobserver variability. The sensitivity of thermography ranged from 78% to 94% compared with 81% to 92% for imaging studies and 77% for EMG. The specificity of thermography ranged from 20% to 44%. Thermography predicted the level of the radiculopathy correctly in less than 50% of cases. Thermography has little or no utility in the diagnosis of lumbosacral radiculopathy.

272: So YT, Aminoff MJ, Olney RK. The role of thermography in the evaluation of lumbosacral radiculopathy. Neurology 1989 Sep;39(9):1154-8

Department of Neurology, University of California, San Francisco 94143.

We studied 27 normal subjects and 30 patients with low back pain to evaluate the diagnostic accuracy of thermography in the diagnosis of lumbosacral radiculopathy. Thermographic abnormality was defined as the presence of either interside temperature difference exceeding 3 standard deviations from the normal mean, or an abnormal heat pattern overlying the lumbosacral spine. In patients with clinically unequivocal radiculopathy, thermography and electrophysiologic study were similar in diagnostic sensitivity, and the 2 methods agreed on the presence or absence of abnormality in 71% of cases. However, the thermographic findings had limited localizing value. Relative limb warming was often seen in patients with acute denervation on EMG, and limb cooling in those with more chronic lesions, but the side of the root lesion could not be identified confidently by thermography alone. Moreover, thermographic abnormalities appeared not to follow a dermatomal distribution and failed to identify the clinical or electrophysiologic level of radiculopathy in most cases. Thus, the thermographic findings are nonspecific, of little diagnostic value, and of uncertain prognostic relevance.

273: Boden SD, Davis DO, Dina TS, Patronas NJ, Wiesel SW. Abnormal magnetic-resonance scans of the lumbar spine in asymptomatic subjects. A prospective investigation. J Bone Joint Surg Am 1990 Mar;72(3):403-8

Department of Orthopaedic Surgery, George Washington University Medical Center, Washington, D.C.

We performed magnetic resonance imaging on sixty-seven individuals who had never had low-back pain, sciatica, or neurogenic claudication. The scans were interpreted independently by three neuro-radiologists who had no knowledge about the presence or absence of clinical symptoms in the subjects. About one-third of the subjects were found to have a substantial abnormality. Of those who were less than sixty years old, 20 per cent had a herniated nucleus pulposus and one had spinal stenosis. In the group that was sixty years old or older, the findings were abnormal on about 57 per cent of the scans: 36 per cent of the subjects had a herniated nucleus pulposus and 21 per cent had spinal stenosis. There was degeneration or bulging of a disc at at least one lumbar level in 35 per cent of the subjects between twenty and thirty-nine years old and in all but one of the sixty to eighty-year-old subjects. In view of these findings in asymptomatic subjects, we concluded that abnormalities on magnetic resonance images must be strictly correlated with age and any clinical signs and symptoms before operative treatment is contemplated.

273a: Boden SD, McCowin PR, Davis DO, Dina TS, Mark AS, Wiesel S. Abnormal magnetic-resonance scans of the cervical spine in asymptomatic subjects. A prospective investigation. J Bone Joint Surg Am 1990 Sep;72(8):1178-84

Department of Orthopaedic Surgery, George Washington University Medical Center, Washington, D.C. 20037.

Previous investigations with plain radiography, myelography, and computed tomography have shown that degenerative disease of the cervical spine frequently occurs in the absence of clinical symptoms. We studied the magnetic resonance-imaging scans of sixty-three volunteers who had no history of symptoms indicative of cervical disease. The scans were mixed randomly with thirty-seven scans of patients who had a symptomatic lesion of the cervical spine, and all of the scans were interpreted independently by three neuroradiologists. The scans were interpreted as demonstrating an abnormality in 19 per cent of the asymptomatic subjects: 14 per cent of those who were less than forty years old and 28 per cent of those who were older than forty. Of the subjects who were less than forty, 10 per cent had a herniated nucleus pulposus and 4 per cent had foraminal stenosis. Of the subjects who were older than forty, 5 per cent had a herniated nucleus pulposus; 3 per cent, bulging of the disc; and 20 per cent, foraminal stenosis. Narrowing of a disc space, degeneration of a disc, spurs, or compression of the cord were also recorded. The disc was degenerated or narrowed at one level or more in 25 per cent of the subjects who were less than forty years old and in almost 60 per cent of those who were older than forty. The prevalence of abnormal magnetic-resonance images of the cervical spine as related to age in asymptomatic individuals emphasizes the dangers of predicating operative decisions on diagnostic tests without precisely matching those findings with clinical signs and symptoms.

273b: Jensen MC, Brant-Zawadzki MN, Obuchowski N, Modic MT, Malkasian D, Ross JS. Magnetic resonance imaging of the lumbar spine in people without back pain.N Engl J Med 1994 Jul 14;331(2):69-73

Hoag Memorial Hospital, Newport Beach, Calif. 92663.

BACKGROUND. The relation between abnormalities in the lumbar spine and low back pain is controversial. We examined the prevalence of abnormal findings on magnetic resonance imaging (MRI) scans of the lumbar spine in people without back pain. METHODS. We performed MRI examinations on 98 asymptomatic people. The scans were read independently by two neuroradiologists who did not know the clinical status of the subjects. To reduce the possibility of bias in interpreting the studies, abnormal MRI scans from 27 people with back pain were mixed randomly with the scans from the asymptomatic people. We used the following standardized terms to classify the five intervertebral disks in the lumbosacral spine: normal, bulge (circumferential symmetric extension of the disk beyond the interspace), protrusion (focal or asymmetric extension of the disk beyond the interspace), and extrusion (more extreme extension of the disk beyond the interspace). Nonintervertebral disk abnormalities, such as facet arthropathy, were also documented. RESULTS. Thirty-six percent of the 98 asymptomatic subjects had normal disks at all levels. With the results of the two readings averaged, 52 percent of the subjects had a bulge at at least one level, 27 percent had a protrusion, and 1 percent had an extrusion. Thirty-eight percent had an abnormality of more than one intervertebral disk. The prevalence of bulges, but not of protrusions, increased with age. The most common nonintervertebral disk abnormalities were Schmorl's nodes (herniation of the disk into the vertebral-body end plate), found in 19 percent of the subjects; annular defects (disruption of the outer fibrous ring of the disk), in 14 percent; and facet arthropathy (degenerative disease of the posterior articular processes of the vertebrae), in 8 percent. The findings were similar in men and women. CONCLUSIONS. On MRI examination of the lumbar spine, many people without back pain have disk bulges or protrusions but not extrusions. Given the high prevalence of these findings and of back pain, the discovery by MRI of bulges or protrusions in people with low back pain may frequently be coincidental.

274c: Borenstein DG, O'Mara JW Jr, Boden SD, Lauerman WC, Jacobson A, Platenberg C, Schellinger D, Wiesel SW.The value of magnetic resonance imaging of the lumbar spine to predict low-back pain in asymptomatic subjects : a seven-year follow-up study. J Bone Joint Surg Am 2001 Sep;83-A(9):1306-11

Division of Rheumatology, George Washington University Medical Center, Washington, DC 20037, USA.BACKGROUND:

In 1989, a group of sixty-seven asymptomatic individuals with no history of back pain underwent magnetic resonance imaging of the lumbar spine. Twenty-one subjects (31%) had an identifiable abnormality of a disc or of the spinal canal. In the current study, we investigated whether the findings on the scans of the lumbar spine that had been made in 1989 predicted the development of low-back pain in these asymptomatic subjects. METHODS: A questionnaire concerning the development and duration of low-back pain over a seven-year period was sent to the sixty-seven asymptomatic individuals from the 1989 study. A total of fifty subjects completed and returned the questionnaire. A repeat magnetic resonance scan was made for thirty-one of these subjects. Two neuroradiologists and one orthopaedic spine surgeon interpreted the original and repeat scans in a blinded fashion, independent of clinical information. At each disc level, any radiographic abnormality, including bulging or degeneration of the disc, was identified. Radiographic progression was defined as increasing severity of an abnormality at a specific disc level or the involvement of additional levels. RESULTS: Of the fifty subjects who returned the questionnaire, twenty-nine (58%) had no back pain. Low-back pain developed in twenty-one subjects during the seven-year study period. The 1989 scans of these subjects demonstrated normal findings in twelve, a herniated disc in five, stenosis in three, and moderate disc degeneration in one. Eight individuals had radiating leg pain; four of them had had normal findings on the original scans, two had had spinal stenosis, one had had a disc protrusion, and one had had a disc extrusion. In general, repeat magnetic resonance imaging scans revealed a greater frequency of disc herniation, bulging, degeneration, and spinal stenosis than did the original scans. CONCLUSIONS: The findings on magnetic resonance scans were not predictive of the development or duration of low-back pain. Individuals with the longest duration of low-back pain did not have the greatest degree of anatomical abnormality on the original, 1989 scans. Clinical correlation is essential to determine the importance of abnormalities on magnetic resonance images.[Boden �90 to Borenstein �01- 67 original no BP <60yrs. 20% HNP, 1% Stenosis v. 60+yrs 36% HNP, 21% Stenosis (31% abnormal canal beyond bulges) F/U 50/67 Now 29/50 f/u developed LBP 8 radicular (4 normal prior scans, 2 stenosis, 1 protrusion, 1 extrusion) 31 repeated MRI greater frequency of HNP, bulge, DDD and stenosis after 7 years, 21 Developed LB MRIs original 12 normal, 5 HNP, 3 stenosis, 1 mod. DDD]

274d: Jarvik JJ, Hollingworth W, Heagerty P, Haynor DR, Deyo RA. The Longitudinal Assessment of Imaging and Disability of the Back (LAIDBack) Study: baseline data. Spine 2001 May 15;26(10):1158-66

Department of Radiology, University of Washington, Seattle 98195, USA. jarvikj@u.washington.edu

STUDY DESIGN: Prospective cohort study of randomly selected Veterans Affairs (VA) outpatients. OBJECTIVE: To determine the prevalence of magnetic resonance imaging (MRI) findings in the lumbar spine among persons without current low back pain or sciatica and to examine which findings are related to age or previous back symptoms. SUMMARY OF BACKGROUND INFORMATION: Previous studies of patients without low back pain have not explored the possible association of various MRI findings to past symptoms. METHODS: We randomly selected an age-stratified sample of subjects without low back pain in the past 4 months from clinics at a VA hospital. We collected information on demographics, comorbidity, functional status, and quality of life. MR images were obtained using a standardized protocol through each of the five lumbar disc levels. RESULTS: Of 148 subjects, 69 (46%) had never experienced low back pain. There were 123 subjects (83%) with moderate to severe desiccation of one or more discs, 95 (64%) with one or more bulging discs, and 83 (56%) with loss of disc height. Forty-eight subjects (32%) had at least one disc protrusion and 9 (6%) had one or more disc extrusions. CONCLUSION: Many MR imaging findings have a high prevalence in subjects without low back pain. These findings are therefore of limited diagnostic use. The less common findings of moderate or severe central stenosis, root compression, and extrusions are likely to be diagnostically and clinically relevant.

274e: Videman T, Simonen R, Usenius J, Osterman K, Battie M. The long-term effects of rally driving on spinal pathology. Clin Biomech (Bristol, Avon) 2000 Feb;15(2):83-6

Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada. tapio.videman@ualberta.ca

OBJECTIVES: To investigate the consequences of rally driving on lumbar degenerative changes. BACKGROUND: Vehicular driving is suspected to accelerate disc degeneration through whole-body vibration, leading to back problems. However, in an earlier well-controlled study of lumbar MRI findings in monozygotic twins, significant effects of lifetime driving on disc degeneration were not demonstrated. Another study of machine operators found only long-term exposure to vibration on unsprung seats led to a reduction in disc height. DESIGN: Case-control study comparing rally drivers with population sample. METHODS: Eighteen top rally drivers and co-drivers, mean age 43 yrs (SD, 10), volunteered for the study. The subjects were interviewed and imaged with a MR scanning and lumbar images were analyzed for degenerative findings using a standard scoring protocol previously published. The reference group was composed of 14 men, mean age 55 yrs (SD, 10), selected from a population sample. RESULTS: Overall results showed no significant differences in lumbar degenerative findings as assessed from MR images between the rally drivers and the reference group; age-adjusted differences were not statistically significant for disc heights, bulges, herniations, end-plate irregularities, or osteophytes. CONCLUSION: Even extreme vehicular vibration as experienced in rally driving does not appear to have significant effects on disc generation. RELEVANCE: The study results do not support driving, and its associated whole body vibration, as a significant cause of disc degeneration and question the theory that the higher incidence of back pain among drivers is due to accelerated disc degeneration. Other driving-related factors, such as postural stress, may deserve more attention.

274f. Videman T, Battie MC. The influence of occupation on lumbar degeneration. Spine 1999 Jun 1;24(11):1164-8

University of Alberta, Canada. tapio.videman@ualberta.ca

In many countries, back problems have been defined as occupational injuries. The belief underlying this injury model is that back symptoms are caused primarily by work-related mechanical factors that damage the structures of the spine, either through a single incident or repeated loading. Although the etiopathogenesis of degenerative findings in the disc and their relation to pain are poorly understood, changes in the disc are suspected of underlying many back symptoms. The focus of this article is on examining the relation between occupational factors and disc degeneration. Occupational factors suspected of accelerating spinal degeneration include accident-related trauma; heavy physical loading and materials handling, including lifting, bending, and twisting; prolonged sitting; and sustained nonneutral work postures and vehicular driving. There is evidence to suggest that occupational exposures have an effect on disc degeneration. However, these factors explain little of the variability in degeneration found in the adult population. Furthermore, the lack of a clear dose-response relation between time spent in various occupational loading conditions and degenerative findings adds to doubts about a strong causal link. The contribution of suspected occupational risk factors appears to be particularly modest when compared with familial influences, which reflect the combined effects of genes and early childhood environment. These findings challenge the dominant role assumed for occupational loading in disc degeneration and associated back problems, and suggest a more complex etiology.

274g: Simonen RL, Videman T, Battie MC, Gibbons LE The effect of lifelong exercise on psychomotor reaction time: a study of 38 pairs of male monozygotic twins. Med Sci Sports Exerc 1998 Sep;30(9):1445-50

Department of Health Sciences, University of Jyvaskyla, Finland. rsimonen@cc.jyu.fi

PURPOSE: The aim was to study the effect of lifetime physical activity on psychomotor speed. METHODS: Foot and dominant hand visual simple and choice psychomotor reaction times were studied among monozygotic twins (38 pairs) aged 35-69, discordant for lifetime exercise histories. RESULTS: There was a trend that some components of psychomotor reaction time were faster for frequent than for occasional exercisers, but the findings were not consistent for the hand and feet. After controlling for occupational physical activity, only choice decision time for the hand (26 ms, P < 0.01) and choice reaction time for the contralateral foot (51 ms, P < 0.05) both remained 7% faster. There was no trend for systematic differences in reaction times between twins engaged in regular exercise versus their siblings exercising infrequently. CONCLUSIONS: Results suggest a somewhat smaller effect of exercise than reported in previous studies. Reaction time may be significantly affected only by vigorous, frequent exercise. Thus, health promotion through exercise may be unlikely to have notable effects on reaction time.

274h: Videman T, Battie MC, Gibbons LE, Manninen H, Gill K, Fisher LD, Koskenvuo M. Lifetime exercise and disk degeneration: an MRI study of monozygotic twins. Med Sci Sports Exerc 1997 Oct;29(10):1350-6

Department of Health Sciences, University of Jyvaskyla, Finland.

Participation in some competitive sports has been shown to increase disk degeneration; however, the long-term effects of recreational physical activities are unclear. We investigated the effects of endurance exercise and power sports on disk degeneration in monozygotic male twins with contrasting lifetime exercise histories. The effects of endurance exercise were studied in 22 discordant twin pairs (mean lifetime frequencies of 3.9 vs 1.1 times/wk), and the effects of power sports were investigated in 12 discordant pairs (2,300 vs 200 h of weightlifting). The age range of the twins was from 35 to 69 yr. No differences in MRI findings between co-twins discordant for endurance exercise were found at any of the spinal regions. Subjects with more power sport involvement had greater disk degeneration in the T6-T12 region (P < 0.03), but similar findings were not present in the lumbar spine. Controlling for recalled back injuries, occupational loading, smoking, and driving did not significantly affect the results. No signs of beneficial or harmful effects of lifetime endurance exercise on disk degeneration were seen. Increased power sport participation was associated with slightly greater disk degeneration in the lower thoracic spine, but not in the lumbar spine.

274i: Battie MC, Videman T, Gibbons LE, Fisher LD, Manninen H, Gill K. 1995 Volvo Award in clinical sciences. Determinants of lumbar disc degeneration. A study relating lifetime exposures and magnetic resonance imaging findings in identical twins.

Spine 1995 Dec 15;20(24):2601-12

Department of Physical Therapy, University of Alberta, Edmonton, Canada.

STUDY DESIGN: Retrospective cohort. OBJECTIVES: To investigate the effects of lifetime exposure to commonly suspected risk factors on disc degeneration using magnetic resonance imaging, and to estimate the effects of these suspected risk factors relative to age and familial aggregation, reflecting genetic and shared environmental influences. SUMMARY OF BACKGROUND DATA: Structural and biochemical changes associated with disc degeneration are suspected as the underlying conditions of many back-related symptoms. Little is known about the determinants of disc degeneration. METHODS: Based on lifetime discordance in suspected environmental risk factors for disc degeneration, 115 male identical twin pairs were selected. An in-depth interview was conducted of occupational and leisure time physical loading, driving, and smoking. Disc degeneration was evaluated using observational and digital magnetic resonance imaging assessment methods. RESULTS: Heavier lifetime occupational and leisure physical loading was associated with greater disc degeneration in the upper lumbar levels (P = 0.055 - 0.001), whereas sedentary work was associated with lesser degeneration (P = 0.006). These univariate associations did not reach statistical significance in the lower lumbar region. In multivariate analyses of the upper lumbar levels, the mean job code explained 7% of the variability in observational disc degeneration scores; the addition of age explained 16%, and familial aggregation improved the model such that 77% of the variability was explained. In the lower lumbar levels, leisure time physical loading entered the multivariate model, explaining 2% of the variability. Adding age explained 9%, and familial aggregation raised the variability in disc degeneration scores explained to 43%. CONCLUSIONS: The present study findings suggest that disc degeneration may be explained primarily by genetic influences and by unidentified factors, which may include complex, unpredictable interactions. The particular environmental factors studied, which have been among those most widely suspected of accelerating disc degeneration, had very modest effects.

274j: Teitz CC, Kilcoyne RF. Premature osteoarthrosis in professional dancers. Clin J Sport Med 1998 Oct;8(4):255-9

University of Washington, Seattle, USA.

OBJECTIVE: The purpose of this study was to determine whether arthrosis begins at an unusually early age in professional dancers; if there is an association between hypermobility and osteoarthrosis in dancers; and if osteoarthrosis is a contributing factor to retirement from a professional career in this population. DESIGN: Dance and injury history; physical examinations of back, lower extremities, and ligamentous laxity; and radiographs of lower extremity joints were performed in retired dancers. The dancers' radiographs were compared to those of age-matched nondancers. The radiologist was blinded to the origin of the radiographs. PARTICIPANTS: Fourteen retired dancers aged 27 to 46 years who had performed professionally for a minimum of 10 years were included in the study. Thirty-six age-matched nondancers with injuries or pain in various lower extremity joints were used as controls. MAIN OUTCOME MEASURES: This study measured radiographic findings of osteoarthrosis, including sclerosis, joint space narrowing, osteophytes, and subchondral cysts; hypermobility (after Klemp) as manifested by > 3 of 5 tests being positive; and the dancers' reasons for retirement. RESULTS: Changes of arthrosis were found in 34 of 56 joints in 14 dancers and in 3 of 36 joints in 36 nondancers. Hip calcifications were found in 10 hips in 7 dancers and in 1 nondancer's hip. None of the participants in this study was hypermobile or had retired because of arthrosis. CONCLUSIONS: The prevalence of arthrosis in knees, ankles, and first metatarsophalangeal joints in young dancers was increased when compared to that of nondancers in the same age group. Arthrosis does not necessarily cause retirement from a performance career.

275: Wiesel SW, Tsourmas N, Feffer HL, Citrin CM, Patronas N A study of computer-assisted tomography. I. The incidence of positive CAT scans in an asymptomatic group of patients. Spine 1984 Sep;9(6):549-51

In order to study the type and number of CAT scan abnormalities of the lumbar spine that occur in asymptomatic people, 52 studies from a control population with no history of back trouble were mixed randomly with six scans from patients with surgically proven spinal disease, and all were interpreted by three neuroradiologists in a blinded fashion. Irrespective of age, 35.4% (26.6%, 51.0%, and 31.3%) were found to be abnormal. Spinal disease was identified in an average of 19.5% (23.8%, 22.7%, and 12.5%) of the under 40-year-olds, and it was a herniated nucleus pulposus in every instance. In the over 40-year-old age group, there was an average of 50% (29.2%, 81.5%, and 48.1%) abnormal findings, with diagnoses of herniated disc, facet degeneration, and stenosis occurring most frequently.

276: Biering-Sorensen F, Hansen FR, Schroll M, Runeborg O. The relation of spinal x-ray to low-back pain and physical activity among 60-year-old men and women. Spine 1985 Jun;10(5):445-51

X-ray findings in the thoracic and lumbar spine from 666 60-year-old men and women from a general population were related to anamnestic data and physical measurements. Disc degenerations were significantly more common among those with low-back pain (LBP) compared with those without. The corresponding calculated predictive values stressed the importance of taking precaution in interpreting the radiologic findings in the clinical situation. In several instances, there were significantly more positive (abnormal) radiologic findings among those with the heaviest work. Disc degeneration and scoliosis were particularly frequent in this regard. Absolute weight and body mass index was significantly higher in persons with spondylosis. The fingertip-floor distance was greater with higher frequency of spondylosis and L4 disc degeneration.

277: Bigos SJ, Hansson T, Castillo RN, Beecher PJ, Wortley MD. The value of preemployment roentgenographs for predicting acute back injury claims and chronic back pain disability. Clin Orthop 1992 Oct;(283):124-9

Department of Orthopaedics, University of Washington, Seattle 98195.

Preemployment roentgenographs have long been used in industry to screen job applicants. Roentgenographs have had little effect, however, in curbing the cost of back problems in industry. This study evaluates the capabilities of preemployment roentgenographs for predicting acute back injury claims within the longshoring industry and for predicting back problems that lead to back disability of more than six months. The data indicate that lumbosacral roentgenographs are not helpful in predicting who is more likely to make a back injury claim, or those few who make up the vast majority of the costs for industrial back pain by becoming disabled for more than six months. Lumbosacral roentgenographs have little link to back disorders and may be viewed as discriminatory. The radiation exposure is not justified by their predictive value as a preemployment screening tool.

278: Deyo RA, Diehl AK. Lumbar spine films in primary care: current use and effects of selective ordering criteria. J Gen Intern Med 1986 Jan-Feb;1(1):20-5

Low back pain (LBP) often prompts radiography, although the diagnostic yield of lumbar spine films is low, and many radiographic abnormalities are unrelated to symptoms. Criteria have been proposed for selective x-ray use, but their value and safety are uncertain. To evaluate these criteria, the authors prospectively studied 621 walk-in patients with LBP. The yield of explanatory x-ray findings was over three times greater among patients with indications for radiography than among those without. Furthermore, an indication for x-rays existed for all patients found to have a malignancy, and for 13 of 14 patients with an identified fracture. Actual physician ordering, however, did not correspond well with the recommended indications. Application of selective criteria appears safe and may improve the yield of useful findings. It may not, however, reduce x-ray utilization from current levels without further refinement in the criteria.

280: Grubb SA, Lipscomb HJ, Guilford WB. The relative value of lumbar roentgenograms, metrizamide myelography, and discography in the assessment of patients with chronic low-back syndrome. Spine 1987 Apr;12(3):282-6

This prospective study evaluated the relative value of lumbar roentgenograms, metrizamide myelography, and discography in identifying structural sources for chronic low-back syndrome. One hundred and eight patients with chronic low-back syndrome were evaluated. Patients had not previously had pathology identified which could explain their pain. On discography, 83 patients (78%) had their pain reproduced at least one abnormal level, identifying a structural component to their pain. Only 22 patients (21%) had all levels of pathology identified by roentgenograms and an additional 17 (16%) had pathology appropriately identified by a combination of myelograms and roentgenograms. Using roentgenograms, myelography, and discography, organic pathology was identified which could explain the patient's symptoms in 100 of 108 patients (93%). Based on this study, we think discography is an important diagnostic tool for use in evaluating patients with chronic low-back syndrome. Discography is essential to adequately identify abnormal levels in patients being considered for fusions. Roentgenograms and myelograms are inadequate evaluation in this chronic pain group in that lack of organic pathology cannot be assumed in the presence of normal roentgenograms and myelograms.

281: Hansson T, Bigos S, Beecher P, Wortley M. The lumbar lordosis in acute and chronic low-back pain. Spine 1985 Mar;10(2):154-5

To evaluate a possible relationship between the amount of lumbar lordosis in asymptomatic as well as subjects with acute and chronic low-back pain, the amount of lordosis was determined from spinal roentgenograms of 600 men between 20 and 63 years of age. The angle between a line parallel to the cranial end-plate of L1 and S1 was defined as the lordosis angle. The amount of lordosis was distributed similarly according to age within each of the three groups and was also similar in comparisons between the groups. The men were randomly selected to represent three different groups. Each group included 200 age-matched subjects with similar occupation. The first group consisted of men claiming no previous back-pain history who underwent spinal x-ray as a part of a preemployment examination. The second group consisted of men who had a spinal x-ray examination after claiming their first low-back injury, but not preemployment screening. The third group consisted of x-ray examination of men evaluated for chronic low back disability. The findings thus indicated that the distribution and range of lordosis as viewed by clinicians and radiologists does not vary in the acute or with chronic low-back pain, more than in men without back pain of the same age.

282: Kaplan DM, Knapp M, Romm FJ, Velez R. Low back pain and x-ray films of the lumbar spine: a prospective study in primary care. South Med J 1986 Jul;79(7):811-4

We prospectively studied 96 men with low back pain to evaluate the association of x-ray findings with clinical diagnosis, treatment, functional outcome, and satisfaction with care. Degenerative joint disease (DJD) was the most common radiologic finding (70%). Making the diagnosis of spinal DJD has little effect on patient management, but patients with x-ray evidence of DJD were three times more likely than those with normal films to receive nonsteroidal anti-inflammatory drugs other than aspirin. Furthermore, patients given a "diagnostic label" of DJD were more likely to express satisfaction with medical care and less likely to seek care elsewhere than patients with similar x-ray results who were given nonspecific diagnoses. These factors will need to be considered in arriving at an estimate of the net benefits of x-ray examination of the lumbar spine.

285: Leboeuf C, Kimber D, White K. Prevalence of spondylolisthesis, transitional anomalies and low intercrestal line in a chiropractic patient population. J Manipulative Physiol Ther 1989 Jun;12(3):200-4

Australian Spinal Research Foundation.

Five hundred and thirty radiographs were screened for the presence of certain lumbosacral anomalies. The prevalence of spondylolisthesis was found to be 5.1%, lumbarization 6.0%, sacralization 5.5% and low intercrestal line 56.9%. There was no greater prevalence in patients suffering from low back pain when compared against those who did not. There was a propensity for a low intercrestal line among females. Contrary to previous claims that lumbarization is more common in men, we found a moderate predilection for this finding among women. No difference between the two sexes was found in the prevalence of sacralization, contradicting previous claims that is more common in females, nor was spondylolisthesis found more frequently in men, contrary to our expectations.

286: Libson E, Bloom RA, Dinari G. Symptomatic and asymptomatic spondylolysis and spondylolisthesis in young adults. Int Orthop 1982;6(4):259-61

The lumbar spine was examined radiologically for the presence of spondylolysis and spondylolisthesis in 936 asymptomatic soldiers prior to military placement and in 662 soldiers complaining of low back pain. The overall incidence of spondylolysis was 9.7% in both groups, but bilateral spondylolysis was more prone to be associated with symptoms than a unilateral defect. In the symptomatic group the incidence of spondylolisthesis was 5.3% but only 2.2% in the asymptomatic group. The defect was seen in the oblique views only in 18.7% of the cases of spondylolysis. The precise diagnosis is important for vocational counselling and military placement.

287: Libson E, Bloom RA, Dinari G, Robin GC. Oblique lumbar spine radiographs: importance in young patients. Radiology 1984 Apr;151(1):89-90

Spondylolysis is a direct precursor of spondylolisthesis and can lead to crippling back pain. Of 1,743 patients surveyed, including 936 who were asymptomatic and 807 with back pain, 165 (including 91 who were asymptomatic and 74 with back pain) had spondylolysis, which was seen only on oblique lumbar views in 20% of cases. Because of the high false-negative rate of AP and lateral views, oblique views are essential in children and young adults. As spondylolysis is rare above L3, radiographs can be limited to L3-S1. Significantly less spondylolysis was seen in persons older than 30, with back pain usually caused by disk degeneration; thus routine oblique views could be safely omitted in older patients.

289: Magora A, Schwartz A. Relation between the low back pain syndrome and x-ray findings. 3. Spina bifida occulta. Scand J Rehabil Med 1980;12(1):9-15

The relation between LBP and SBO was studied in 1244 subjects, of which 800 had LBP and 444 served as controls. Sex, age, occupational characteristics, spine curvatures, spinal movements and work history were compared. It is concluded that SBO does not play a causative role, does not cause a proneness to LBP and does not influence the chronicity of LBP. Some data seem to indicate that the severity of LBP may be increased by SBO.

290: Magora A, Schwartz A. Relation between low back pain and X-ray changes. 4. Lysis and olisthesis. Scand J Rehabil Med 1980;12(2):47-52

In a comparative study of 1024 low back pain and healthy subjects, prelysis was found in 16.4%, lysis in 10.5% and olisthesis in 2%. No relation between prelysis and lysis, and low back pain was found. Lysis seemed to be associated with a higher severity of low back pain. All the subjects with olisthesis suffered from low back pain. Based on these findings, it is concluded that lysis or pre-lysis should not be a ground for the exclusion of candidates to any occupation, but that olisthesis should, and that both lysis and olisthesis should be accepted as roentgenological findings in which the severity of low back pain may be higher, thus justifying a more prolonged sick leave.

291: Paajanen H, Erkintalo M, Dahlstrom S, Kuusela T, Svedstrom E, Kormano M. Disc degeneration and lumbar instability. Magnetic resonance examination of 16 patients. Acta Orthop Scand 1989 Aug;60(4):375-8

Department of Surgery, Central Hospital of Mikkeli, Finland.

Flexion and extension radiographs of 75 young males with low back pain disclosed abnormal segmental motion of the lumbar spine in 16 patients with translational movements in 20 intervertebral segments. These 16 patients were further investigated by magnetic resonance imaging to assess disc degeneration in the unstable segments. On T2-weighted images of the 20 segments, the disc was normal in 13 and degenerated in only 7 patients. Thus, the initial factor in lumbar instability in young patients with low back pain is not always degeneration of the disc.

293: Sward L, Hellstrom M, Jacobsson B, Peterson L. Back pain and radiologic changes in the thoraco-lumbar spine of athletes. Spine 1990 Feb;15(2):124-9

Department of Orthopaedics, East Hospital, Gothenburg, Sweden.

Back pain and radiological changes of the thoraco-lumbar spine were investigated in 142 top athletes, representing wrestling, gymnastics, soccer and tennis (age range 14-25 years). All groups of athletes reported back pain at high frequencies (50-85%). Male gymnasts had significantly increased incidence and severity of back pain as compared to the rest of the athletes. Radiological abnormalities occurred in 36-55% of the athletes. Reduced disc height, Schmorl's nodes and change of configuration of vertebral bodies correlated with back pain (P less than 0.05, P less than 0.01 and P less than 0.05). Significant covariation between these types of abnormalities was found. Athletes with great demands on the back are thus subjected to an increased risk of symptomatic damage of the spine.

294: Torgerson WR, Dotter WE. Comparative roentgenographic study of the asymptomatic and symptomatic lumbar spine. J Bone Joint Surg Am 1976 Sep;58(6):850-3

A comparative roentgenographic study was carried out on 217 asymptomatic patients between forty and seventy years old and 387 symptomatic patients in the same age range. Spondylosis (osteophyte formation) did not appear to have any direct relationship to low-back pain. Degenerative disc disease appeared to be a major cause of low-back pain. Spondylolysis and spondylolisthesis occurred more frequently in the symptomatic than in the asymptomatic patients. Routine roentgenograms of the lumbosacral spine were useful in evaluating patients seen for treatment of low-back pain.

295: Boxall D, Bradford DS, Winter RB, Moe JH. Management of severe spondylolisthesis in children and adolescents. J Bone Joint Surg Am 1979 Jun;61(4):479-95

Forty-three patients with a fifth lumbar-first sacral spondylolisthesis of 50 per cent or greater were reviewed. Four had been treated non-operatively; eleven, by arthrodesis; eighteen, by decompression and arthrodesis; and ten, by reduction and arthrodesis. The angle of slipping (measurement of the kyphotic relationship of the fifth lumbar to the first sacral vertebra) was found to be as important a measurement as the percentage of slipping in measuring instability and progression of slipping. Hamstring tightness did not correlate with neural deficit. Arthrodesis alone, even in the presence of minor neural deficits, tight hamstrings, or both, gave relief of pain and resolution of neural deficits and tight hamstrings. Our experience with a limited number of patients suggests that management by postoperative extension casts may achieve a significant reduction in percentage of slipping and in angle of slipping. Progression of the spondylolisthesis may occur following a solid arthrodesis.

296: Hall FM. Back pain and the radiologist. Radiology 1980 Dec;137(3):861-3

The exact role of the radiologist in assessing patients with low back pain remains vague, which is in keeping with this syndrome's uncertain etiology and controversial therapy. Conventional radiographs of the lumbosacral spine have a limited role in most such patients, primarily in excluding neoplasm, infection, or ankylosing spondylitis. This examination can ordinarily be limited to two views; and, for radiation and economic reasons, radiographs should usually be initially deferred in young patients and/or those with acute symptoms. Symptoms will abate in most of these patients, making radiological examination unnecessary. Computed tomography (CT) is the method of choice in the diagnosis of spinal stenosis and possibly herniated nucleus pulposus and facet joint abnormalities as well. Preliminary data showing symptomatic relief of pain following facet joint injection could open an entire new area of interventional radiology. Confirmatory studies are needed in this exciting and potentially important area of investigation.

297: Kent DL, Haynor DR, Larson EB, Deyo RA Diagnosis of lumbar spinal stenosis in adults: a metaanalysis of the accuracy of CT, MR, and myelography. AJR Am J Roentgenol 1992 May;158(5):1135-44

Health Services Research and Development Service, VA Medical Center, Seattle, WA 98108.

We undertook a literature synthesis of CT, MR, and myelographic studies to evaluate what is known about the diagnostic accuracy of these imaging tests for the diagnosis of lumbar spinal stenosis in adults without prior surgery. From 116 possibly relevant studies, we reviewed 14 articles that included cases of spinal stenosis with a reference standard other than the imaging tests of interest. Of the studies we reviewed, two involved only MR, nine only CT, and three used both; six studies included myelography. Rating categories of A, B, C, or D were assigned for the quality of research methods used to estimate diagnostic accuracy. All studies received either a C or D rating. Common methodologic problems were failure to assemble a representative cohort for study, small sample size, and failure to maintain independence between image readings and reference standards. Sensitivity ranged from 0.81 to 0.97 for MR, from 0.70 to 1.0 for CT, and from 0.67 to 0.78 myelography. Studies varied greatly in case selection, definition of test and disease categories, and geographic locale, so no pooled estimates could be derived. In asymptomatic patients, abnormal findings appeared on CT or MR in 4-28% of cases and were more common in the elderly. Published studies of the value of CT and MR for the diagnosis of lumbar stenosis lack methodologic rigor and do not permit strong conclusions about the relative diagnostic accuracies of these procedures. For the present, the choice between MR or CT depends on issues such as costs, reimbursements, access to equipment, skill of radiologists, and patient safety. Better studies will be needed to document claims for improvements in imaging accuracy as MR technologies evolve. These studies should emphasize larger sample sizes, more attention to research designs that avoid methodologic biases, and the contribution of imaging diagnoses to ultimate clinical outcome.

298: Fries JW, Abodeely DA, Vijungco JG, Gaffey WR. Lateral L3/4 herniated nucleus pulposus: clinical and imaging considerations. Comput Radiol 1984 Nov-Dec;8(6):341-54

This report examines 18 surgically proven L3/4 herniated nucleus pulposus (HNP), all having myelogram, CT and adequate neurological evaluation. It will focus on four cases where the herniation involved the neural canal (intervertebral canal). Comparison to the 14 spinal canal central herniations will be made. The clinical findings for lateral L3/4 HNP allowed a preimaging diagnosis to be made in three of the four cases. In the central group the correct preimaging diagnosis was made one of the 14 cases (P less than 0.01). There are numerous reasons why the central L3/4 HNP preimaging diagnosis is inaccurate as well as difficult to establish and these reasons are discussed in detail. The myelographic and CT findings of the lateral L3/4 HNP are clearly elaborated. All herniations were extruded. They poorly responded to conservative management. The duration of illness, onset of pain to surgical disk removal, for the lateral herniations was 34.8 days and, 154.4 days for the central group (P less than 0.05). The myelogram is a disappointing test in the diagnosis of lateral L3/4 HNP, but highly accurate in spinal canal L3/4 HNP. CT is a preferred imaging test being virtually positive in all cases.

299: Gillstrom P, Ericsson K, Hindmarsh T A comparison of computed tomography and myelography in the diagnosis of lumbar disc herniation. Arch Orthop Trauma Surg 1986;106(1):12-4

Ninety patients suspected to have a herniated lumbar disc were examined by myelography and computed tomography (CT). Of these, 37 were subjected to surgery. The surgical findings were in agreement in 21 patients (57%) with the myelograms and in 28 patients (76%) with the CT examinations. False-positive CT examinations were found in only one patient. CT is as reliable as myelography in the primary diagnosis of disc herniation.

300: Haughton VM, Eldevik OP, Magnaes B, Amundsen P. A prospective comparison of computed tomography and myelography in the diagnosis of herniated lumbar disks. Radiology 1982 Jan;142(1):103-10

Although CT effectively demonstrates normal and herniated intervertebral disks, the value of CT in low back pain has not been adequately evaluated. We compared CT prospectively with myelography in 107 patients referred to Ulleval Hospital Department of Radiology for myelography. Fifty-two patients subsequently had spinal explorations, one patient twice during the study and two patients at two levels. Forty-six CT and 44 myelographic diagnoses agreed perfectly with the operative diagnosis at that level. In 30 disk herniations, there were 29 true-positive CT diagnosis and 28 true-positive myelographic diagnoses. False-negative diagnoses of herniated nucleus pulposus were made twice on myelography and once on CT. In 24 other spinal operations, there were eight false-positive CT and nine false-positive myelographic diagnoses of herniated nucleus pulposus. CT demonstrates lumbar disk disease as effectively as myelography.

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