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Herniated Discectomy 
 
Panel findings and recommendations: 
    
 -   It is recommended that the treating clinician discuss further treatment options, with the patient with sciatica after approximately 1 month of conservative therapy.  The clinician should consider referral to a specialist when all of the following conditions are met: (1) sciatica is both severe and disabling, (2) symptoms of sciatica persist without improvement or with progression, and (3) there is clinical evidence of nerve root compromise.  (Strength of Evidence = B.) 
 -   Standard discectomy and microdiscectomy are of similar efficacy and appropriate for selected patients with herniated discs and nerve root dysfunction.  (Strength of Evidence = B.) 
 -   Chymopapain is an acceptable treatment for such patients, but less efficacious than standard or microdiscectomy.  If chymopapain is being considered, testing patients for allergic sensitivity to this substance can reduce incidence of anaphylaxis.  (Strength of Evidence = C.) 
 -   Percutaneous discectomy is significantly less efficacious than chymopapain in treating patients with lumbar disc herniation.  This and other new methods of lumbar disc surgery are not recommended until they can be proven efficacious in controlled trials.  (Strength of Evidence = C.) 
 -   Patients with low back pain alone, who have neither suspicious findings for a significant nerve root compression nor any positive "Red Flags," do not need surgical consultation for possible herniated lumbar  disc. (Strength of Evidence = D.)  
 
  Without strong concordant findings the patient's best opportunity is to rely upon the natural history while improving comfortable activity tolerance through exercise (Disability Prevention after Diagnostics or Procedures).   Surgery for sciatica due to herniated discs is invasive and comprises all types of surgical and injection techniques to remove or reduce the size of herniated intervertebral discs that compress nerve roots.  Included are standard discectomy, microscopic discectomy, percutaneous discectomy, and chemonucleolysis (chymopapain injection).  The therapeutic objective is to relieve pressure on nerve roots and reduce pain and possibly weakness and/or numbness in the lower extremities.  
 
 
Literature Reviewed     Evidence on Efficacy   Potential Harms and Costs      Summary of Findings     Author's Example 
 
Herniated Disc Surgery for Sciatica  
 
  Literature Reviewed.  Of 345 articles screened for this topic, 13 reporting on 10 studies met criteria for review.322, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339  In addition, a meta- analysis article was reviewed by the panel.340  Other articles contained information used by the panel, but did not meet article selection criteria.30, 40, 49, 50, 341, 342, 343, 344, 345 
 
  Evidence on Efficacy.    Three of the studies reviewed were randomized controlled trials (RCTs) that evaluated chymopapain as compared with standard discectomy for patients with symptoms and findings of lumbosacral radiculopathy.  Crawshaw, Frazer, Merriam, et al.328 found that at 1-year followup, 85 percent of those undergoing discectomy had good or excellent results, compared to 44 percent of those receiving chymopapain injections.  Both groups had improved leg symptoms, but only the discectomy group had significant improvements in back pain. 
 
  Ejeskär, Nachemson, Herberts, et al.329 found that at 6 months, 56 percent of patients initially receiving Chymopapain injections had undergone surgery due to unrelieved symptoms (all of these patients with disc herniation confirmed at surgery).  When patients were followed up during the first 6 months before any treatment crossovers occurred, those receiving discectomy reported significantly greater improvement in symptoms than those receiving chymopapain injections. 
 
  Van Alphen, Braakman, Bezemer, et al.336 found that at 1-year followup, physicians rated significantly more of the patients in the discectomy group as having good results from their initial treatment compared with the chymopapain group (85 percent compared with 63 percent). Also, 25 percent of the chymopapain group required subsequent discectomy while only 3 percent of the discectomy group needed a second operation. Open discectomy following prior failed chymopapain injection was successful in 44 percent of the cases. 
 
  Another RCT (reported in Fraser; 330  Fraser;331 and Gogan and Fraser332) evaluated chymopapain injections compared with intradiscal saline injections in patients who had sciatica and evidence of a herniated lumbar disc, but who had not improved after 6 months of conservative therapy.  Treatment success rates were significantly better for the chymopapain group than for the saline group at 6-month followup (80 percent compared with 57 percent), at 5-year followup (73 percent compared with 47 percent), and at 10-year followup (80 percent compared with 34 percent). Also, significantly fewer patients required a laminectomy for unrelieved symptoms in the chymopapain group compared with the saline group when followed up at 2 years (20 percent compared with 40 percent) and at 10 years (20 percent compared with 47 percent). 
 
  A double-blind RCT by Javid, Nordby, Ford, et al.333 evaluated chymopapain injection compared with intradiscal saline injection in 108 patients with sciatica who had not improved after at least 6 weeks of conservative treatment including 2 weeks of bed rest.  All patients had positive straight leg raising, a neurologic defect on physical examination, and myelogram evidence of a single lumbar disc herniation.  At 6 months postinjection, the treatment success rate was significantly better for the chymopapain group compared with the saline injection group (83 percent compared with 42 percent). 
 
  Revel, Payan, Vallee, et al.334 evaluated chymopapain injections compared with percutaneous discectomy in 141 patients with sciatica who did not improve after 1 month of conservative treatment.  Overall success rates were significantly better for the chymopapain group than for the percutaneous discectomy group at both 6-month followup (61 percent compared with 44 percent) and 1-year followup (66 percent compared with 37 percent). Also, fewer patients in the chymopapain group required open laminectomy within 1 year due to unrelieved symptoms as compared with the percutaneous discectomy group (7 percent compared with 33 percent). 
 
  Only one RCT (reported by Weber338, 339) compared standard discectomy with conservative (nonsurgical) care.  This study looked at 280 patients who consecutively presented to a hospital neurology department with severe sciatica and clinical findings of possible or definite L4-L5 or L5-S1 disc herniation.  All patients were initially hospitalized for 2 weeks of conservative treatment including 1 week of strict bed rest.  After 2 weeks, 87 patients with possible but indefinite disk hernia who had shown continuous improvement were assigned to continued conservative care, and discectomy was performed for 67 patients who were deemed by their surgeon to have emergent indications for immediate surgery (intolerable pain, suddenly occurring or progressive muscle weakness, or impending bladder or anal sphincter paresis).  This left a group of 126 subjects who had continued sciatic symptoms provoked by mild exercise, sitting, or Vasalva maneuver and with myelograms that showed definite disc herniations consistent with their clinical findings of neurologic dysfunction. Patients in this latter group were randomly assigned to receive either standard discectomy or continued conservative treatment. 
 
  Of these 126 subjects with definite disc hernia who were randomized, Weber338, 339 found good or fair results in 61 percent of the nonsurgery group and in 90 percent of the discectomy group at 1-year followup.  This difference was no longer significant on followup at 4 years (86 percent compared with 89 percent) or 10 years (93 percent compared with 92 percent).  At 4-year followup, considerable sciatic pain was still reported by 9 to 10 percent of each group and considerable low back pain by 11 to 12 percent of each group. (Similar findings to those of Weber were confirmed in the 2006 SPORT study headed by Weinstein et al.,.) At 10-year followup, no patients in either group reported these symptoms.  During the first year, 26 percent of the nonsurgery group demanded discectomy because of unrelieved sciatic pain. On followup, good or fair results were reported for 82 percent of this group at 4 years and for 100 percent of the group at 10 years.  
 
  Tullberg, Isacson, and Weidenhielm335 evaluated microdiscectomy compared with standard discectomy in a RCT of patients with sciatica who had not improved after 2 months of conservative treatment and had evidence on CT scan of a single-level disc herniation.  At 1-year followup, no significant difference was noted between microdiscectomy and standard discectomy groups in terms of patients reporting excellent or good results (86 percent compared with 90 percent), mean postoperative time off work (10.4 weeks compared with 10.1 weeks), or mean improvement in visual analog pain scale ratings over the prior year. 
 
  A meta-analysis for herniated lumbar disc surgery by Hoffman, Wheeler, and Deyo340 found only two RCTs.336 
, 338, 339  This meta-analysis concluded that patients with severe leg symptoms and confirmed lumbar disc herniation experienced faster symptom relief and improved functioning if they underwent standard discectomy rather than conservative treatment.  The meta-analysis stated that there was inadequate evidence available to determine the efficacy of microdiscectomy or percutaneous discectomy for treating low back problems.  However, percutaneous discectomy was noted to have a higher reoperation rate than standard discectomy. Discectomies were noted to be relatively safe procedures, but reoperations were also reported to be fairly common. 
 
  Several studies have emphasized the role psychosocial factors play in influencing the outcome of surgery for herniated disc.30, 40, 49, 50  In fact, Spengler, Ouellette, Battié, et al.50 found that psychological factors, especially elevated hysteria or hypochondriasis scales on a Minnesota Multiphasic Personality Inventory (MMPI), were better predictors of surgical outcome than were findings on imaging studies. 
 
  Potential Harms and Costs.  Reported complications of herniated disc surgery include operative mortality, wound infection, discitis, dural tears, nerve root injuries, thrombophlebitis and pulmonary emboli, meningitis, cauda equina syndrome, psoas hematoma, vascular injuries, and risks associated with transfusions.  Hoffman, Wheeler, and Deyo340 stated that, overall, complications appeared to occur infrequently, but that information on complications was often hard to interpret in the studies reviewed, making determination of rates difficult.  
 
  A community-based study in Michigan, which reviewed the hospital discharge records of over 28,000 patients who had a lumbar disc surgery in 1980, reported incidence rates of 0.06 percent for mortality, 0.3 percent for infections treated with intravenous antibiotics, and 0.3 percent for major neurologic complications.  A similar study of hospital discharge records in Washington State found an overall mortality incidence of 0.07 percent for spinal surgery.345 
 
  The reported complications for chymopapain therapy include allergic reactions (some resulting in death), discitis, thrombophlebitis, pulmonary embolus, neurologic injury, vascular injury, and transverse myelitis.341,342, 343, 344  Skin tests for sensitization before chymopapain injection are reported to significantly reduce the risk of allergic reaction.  Transverse myelitis is uncommon, and the risk factors for this are unclear. 
 
  Complication rates for discectomy are generally low.  Complication rates for chymopapain are also low, but the use of chymopapain has decreased drastically in the United States because of concerns about transverse myelitis and anaphylactic reactions.  The use of tests for allergic sensitization to chymopapain before this treatment may reduce the risk of allergic reaction. 
 
  Surgery for herniated discs is considered an expensive treatment. 
 
  Summary of Findings.  Lumbar discectomy may relieve symptoms faster (as documented by Peul`08) than continued nonsurgical therapy in patients who have severe and disabling leg symptoms (associated with clinical examination findings of definite lumbar nerve root compromise) and who have not improved after 4 to 8 weeks of adequate nonsurgical treatment.  Prospective studies now indicate that only strong obvious findings predict a reasonable outcome (Carragee et al, Shade et al, Hansson & Hannson).50a-d  However, the evidence also showed that in such non-emergent patients, there appears to be little difference in long-term outcomes at 4 and 10 years between discectomy and conservative care. With strong obvious findings cost savings in work absence favors early surgery.Hout`08 
 
  There are direct methods of nerve root decompression and indirect methods.  The best results from herniated disc surgery were with direct methods of standard discectomy and microscopic discectomy with no significant difference in results noted between these procedures.  Studies indicate that the direct method of standard discectomy produces better results than the indirect method of chymopapain.  Chymopapain is better than placebo injections of saline or the indirect method of percutaneous discectomy.  Rates of initial treatment failure requiring a subsequent surgery are higher for chymopapain than for discectomy. 
 
  No studies by 1994 had shown that any of the newer indirect methods of disc surgery, such as indirect automated percutaneous and percutaneous laser discectomy, produce better results than standard discectomy or chymopapain in appropriate patients. [Randomized trial by Barendse et al. 2001 and review by Niemiesto`03 found no effect for percutaneous radiofrequency alteration of internal disc mechanics] 
 
  Patient preference does but should only play a large role in the surgical decision, if the patient has both adequate available information and the ability to weigh the efficacy and risks within reasonable expectations. 
 
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