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X-rays  
 
Panel findings and recommendations: 
 -   Plain x-rays are not recommended for routine evaluation of patients with low back problems within the first month of symptoms unless a red flag is noted on clinical examination (such as specified below). (Strength of Evidence = B.) 
 -   Plain x-rays of the lumbar spine are recommended for ruling out fractures in patients with low back problems when any of the following Red Flags are present: recent significant trauma (any age), recent mild trauma (patient over age 50), history of prolonged steroid use, osteoporosis, patient over age 70.  (Strength of Evidence = C.) 
 -   Plain x-rays in combination with CBC and ESR may be useful for ruling out tumor or infection in patients with low back problems when any of the following red flags are present: prior cancer or recent infection, fever over 100 °F, IV drug abuse, prolonged steroid use, low back pain worse with rest, unexplained weight loss.  (Strength of Evidence = C.) 
 -   In the presence of red flags, especially for tumor or infection, the use of other imaging studies such as bone scan, CT, or MRI may be clinically indicated even if plain x-rays are negative. (Strength of Evidence = C.) 
 -   The routine use of oblique views on plain lumbar x-rays is not recommended for adults in light of the increased radiation exposure. (Strength of Evidence = B.)  
 
  X-ray, or radiography, is the oldest and most widely available modality for imaging the lumbar spine.  The most commonly used x-ray views of the lumbar spine, the standard anteroposterior and lateral views, permit assessment of lumbar alignment, comparison of vertebral body and disc space size, assessment of bone density and architecture, and gross evaluation of soft tissue structures.  Oblique views of the lumbar spine are used in the detection of unilateral or bilateral spondylolysis.  Other special views include sacroiliac views to evaluate possible ankylosing spondylitis.  The diagnostic objective of x-rays is to reveal the bony and structural abnormalities associated with back pain. 
 
Plain X-Rays 
Literature Reviewed     Evidence on Efficacy   Potential Harms and Costs      Summary of Findings     Author's Example 
 
Request for early X-ray? An X-ray is considered for "Red Flag" concerns about tumor, infection or significant trauma as described in the AHCPR Guide 14 evaluation of the reliable literature.  Otherwise one must justify to the patient concerns about radiation exposure which is considered significant (Hall '75 gonadal radiation = 6, 16 or 96 years of daily chest x-ray) since two different studies found that enlightened information beyond the physical examination is possible in but 1/2500 sets of spine X-rays (X-ray Potential harms and risks, X-ray Summary of Findings).  
 
Plain X-ray 
  Literature Reviewed.  Of the 128 articles screened for this topic, 20 articles reporting on 18 studies met criteria for review.26, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294  Other articles contained information used by the panel, but did not meet article selection criteria.295, 296 
 
  Evidence on Efficacy.    Two articles evaluated patients who had less than 3 months of symptoms. 26, 276  Two articles involved patients with chronic low back pain.282, 292  Two articles had three separate groups, one asymptomatic, one with patients seen for low back problems, and a third comprising patients with chronic low back symptoms.277,281  The remaining 14 articles (reporting on 13 studies) involved a mix of patients with acute and chronic symptoms or did not report symptom duration.276, 279, 280, 283, 284, 285, 286, 287, 288, 289, 290, 291 ,292 ,293 ,294 
 
  Hansson, Bigos, Beecher, et al.281 evaluated the degree of lumbar lordosis seen on x-rays in three groups of age-matched men engaged in heavy labor jobs.  They included 200 asymptomatic subjects who had preemployment x-rays, 200 patients seen for low back problems, and 200 patients with low back disability longer than 6 months.  Films were read by back specialists blinded to all other data.  No differences were found between groups in the degree of lordosis noted on x-ray. 
 
  Deyo and Diehl278 evaluated the use of a set of criteria based on medical history questions for selectively ordering x-rays in 621 patients presenting to a hospital emergency room with low back pain (patients with urinary tract symptoms excluded).  The 11 criteria, any one of which would prompt an early x-ray, were: (1) age over 50, (2) significant trauma, (3) neuromotor deficits, (4) unexplained weight loss, (5) suspicion of ankylosing spondylitis, (6) drug or alcohol abuse, (7) history of cancer, (8) use of corticosteroids, (9) temperature greater than or equal to 100 °F, (10) a return visit for the same problem within 1 month and not improved, and (11) patients seeking compensation for back pain. 
 
  X-ray findings were considered therapeutically important if they detected a malignancy or fracture.  Of these patients who had x-rays, 227 met one or more of the criteria for x-ray, and 6.6 percent of these had therapeutically important findings.  Another 84 patients had x-rays even though they did not meet any of the criteria.  None of this group had therapeutically important x-ray findings.  The highest diagnostic yield was in patients over age 50.  Of the 119 patients in this group, 11 percent had therapeutically important findings (13 fractures and 2 malignancies). Strict use of the selective criteria would have resulted in x-ray studies in 390 patients. 
 
  Deyo and Diehl26 evaluated 1,975 walk-in patients at a public hospital, their chief complaint back pain, in order to estimate the prevalence of cancer as an underlying cause of back pain.  A search of an institutional tumor registry at least 6 months after the index visit identified 13 of these patients whose back pain was attributed to cancer. History findings significantly associated with the diagnosis of cancer were age over 50, prior cancer history, unexplained weight loss, pain lasting more than 1 month, and no improvement following conservative therapy. Laboratory test results significantly associated with cancer were an ESR over 20 and anemia.  The authors presented an algorithm for ordering x-rays based on these history and lab test findings that would have resulted in 22 percent of the total group receiving x-rays including all patients who were found to have cancer. 
 
  Eleven articles evaluated x-ray findings in patients with low back problems, compared with asymptomatic subjects with no history of back problems.  The findings of all of these studies were similar.  In general, x-ray findings correlated poorly with low back problems.276, 277, 279, 281, 284, 287, 288, 291, 292, 294 
 
  In all these studies, degenerative changes were noted in some persons with no history of low back problems whereas other persons with back problems showed no degenerative changes.  When groups of subjects of similar age were compared, some studies show an increased prevalence of degenerative changes of the lumbar spine in those who have had back problems, compared to control groups with no history of back problems. Other studies found no significant difference in prevalence of degenerative changes between these groups. 
 
  These studies generally support the idea that degenerative changes of the spine, as seen on x-rays or other imaging studies, are not by themselves a cause of back pain.  In fact, many authors suggest that degenerative changes of the spine are merely signs of aging of the back. Furthermore, degenerative changes were seen more commonly with increasing age for both those with and those without a history of low back problems. 
 
  A possible exception is spondylolisthesis, a forward slippage of a vertebra on the one below it.  Two studies showed significantly higher prevalence of spondylolisthesis in patients with low back problems than in asymptomatic individuals.  Torgerson and Dotter294 found spondylolisthesis on x-rays in 4.9 percent of 387 symptomatic low back pain patients, but in only 1.5 percent of 217 asymptomatic subjects.  Magora and Schwartz,290 who evaluated adults currently working, found x-ray evidence of spondylolisthesis in 3.1 percent of 648 subjects with a history of low back pain patients, but in none of 376 subjects who had never had back pain. 
 
  Three other studies found no significant difference in prevalence of spondylolisthesis between groups with low back problems and asymptomatic controls.  Biering-Sorensen, Hansen, Schroll, et al.276 evaluated a group of men and women 60 years of age, including 308 with low back pain and 358 asymptomatic controls.  This study found an overall prevalence of spondylolisthesis of 2.8 percent, with no significant difference between the groups of symptomatic patients and controls.  Bigos, Hansson, Castillo, et al. 277 found no difference in incidence of spondylolisthesis or other abnormalities in the evaluation of age-matched males whether asymptomatic job applicants, back injury claimants, or disabled patients with greater than 6 months' duration of symptoms.  Leboeuf, Kimber, and White285 found spondylolisthesis on x-rays in 4.9 percent of patients with low back pain and in 5.5 percent of asymptomatic controls.  This difference was not significant. 
 
  None of the studies reviewed on spondylolisthesis attempted to measure spinal instability, and most did not compare groups in terms of degree of spondylolisthesis.  In addition, these studies did not investigate whether there was any therapeutic benefit from determining if a patient has spondylolisthesis (especially in patients with no findings that suggest nerve root compression). 
 
  Some authors maintain that adults with severe spondylolisthesis (degree of slip greater than 50 percent or a severe increase in affected joint motion) may require special treatment.295  However, the degree to which spondylolisthesis and abnormal motion may benefit from special interventions is controversial and beyond the scope of this guideline. 
 
  Other reported findings on lumbar x-rays for adult patients with low back problems included: transitional vertebrae (lumbarization or sacralization), spina bifida occulta, increased or decreased lordosis, mild or moderate scoliosis and spondylolysis (an interarticular defect of the posterior vertebral arch), and degenerative joint disease.  These findings were reported in similar frequency for 200 subjects without symptoms, for 200 subjects reporting back injury claim, and for 200 subjects disabled more than 6 months.  This confirms multiple studies that have questioned both the use of lumbar radiographs for preemployment screening and the diagnostic significance of many radiologic findings.277 
 
  Spondylolysis without spondylolisthesis is equally common in persons with and without low back symptoms.277 
 Spondylolysis has not been documented to be a cause or precursor of low back problems in adults, and no special treatment is required. 
 
  Potential Harms and Costs.  Potential harms associated with lumbar spine x-rays are primarily related to the degree of ionizing radiation exposure. Small cumulative doses of ionizing radiation are believed to present minimal or no risks.  But lumbar x-rays expose the male and female reproductive organs, especially with routine use of oblique views or repeated exposures.  These practices are of questionable value and a particular concern for younger females.  Oblique lumbar views approximately double total radiation exposure, compared to standard views, which alone are equivalent to female gonadal radiation of daily chest x-rays for 6, 16, or 96 years, depending upon the machine.296  Lumbar spine x-rays are seldom indicated during pregnancy. 
 
  The cost of a lumbar spine x-ray is low compared to other imaging modalities such as bone scan, CT, or MRI, and x-rays are more readily available. 
 
  Summary of Findings.  Plain lumbar x-rays have been demonstrated to be useful in helping detect or define spinal fractures, but alone do not rule in or out tumors or infections suspected by other findings (such as when red flags are present).  Evidence suggests plain x-rays are rarely useful in evaluating or guiding treatment of adult low back pain in the absence of red flags.  Plain x-rays are not effective for diagnosing lumbar nerve root impingement of herniated disc or spinal stenosis, or for ruling out cancer or infection. 
 
  The use of lumbar x-rays to screen for spinal degenerative changes, congenital anomalies, spondylolysis, spondylolisthesis, or scoliosis very rarely adds useful clinical information.  Only 1 of 2,500 x-rays detects something not suspected on medical history and physical examination that has an impact on patient care (Brolin`75).  Even in the rare cases where a condition may be clinically significant, the history and physical examination findings (that is, evidence of neurologic dysfunction) should dictate more extensive diagnostic evaluation whether a routine x-ray screening is positive or negative.  Oblique lumbar x-rays, usually done to screen for spondylolysis, rarely add useful clinical information in adults, and they double the x-ray dose to the patient.  Patients with spondylolisthesis can be safely treated in the same fashion as those with other types of low back problems.  Thus, x-rays done specifically to screen for the presence of spondylolisthesis are unnecessary in adults during the first 3 months of symptoms. 
 
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