title: Degenerative spondylolisthesis does not affect the outcome of unilateral laminotomy with bilateral decompression in patients with lumbar stenosis.
abstract: METHODS
  Prospective subcohort study.
  
  
  OBJECTIVE
  To determine whether preoperative presence of degenerative spondylolisthesis worsens the outcome of patients undergoing unilateral laminotomy with bilateral decompression for lumbar stenosis.
  
  
  BACKGROUND
  The standard surgical treatment for degenerative spondylolisthesis with lumbar stenosis is lumbar fusion after standard laminectomy. Although this strategy is widely adopted, it is not supported by class I evidence. This strategy assumes that degenerative spondylolisthesis worsens the outcome of laminectomy by causing postoperative instability. However, instability may be reduced or prevented by the use of less invasive decompression techniques.
  
  
  METHODS
  To test the hypothesis that preoperative degenerative spondylolisthesis worsens the outcome of less invasive lumbar decompression, we performed a prospective cohort study of 165 consecutive patients who underwent unilateral laminotomy with bilateral decompression at our institution. The patients were prospectively followed with a standardized questionnaire, 36-Item Short Form Health Survey, and standing lumbar radiographs for a maximum follow-up period of 5 years. According to the presence or absence of degenerative spondylolisthesis, the patients were divided into 2 groups: an olisthesis group and a nonolisthesis group.
  
  
  RESULTS
  The average 36-Item Short Form Health Survey physical score and bodily pain score improved substantially immediately after surgery. This improvement was maintained up to 5 years postoperatively. Progression of slippage was uncommon in both groups, with an overall incidence of 8% at 5 years of follow-up. There was no significant difference in the average physical score, the bodily pain score, or the rate of progression of slippage between the olisthesis and nonolisthesis groups.
  
  
  CONCLUSIONS
  Our study thus indicates that preoperative degenerative spondylolisthesis does not worsen the outcome of patients with lumbar stenosis undergoing unilateral laminotomy with bilateral decompression. These results suggest that lumbar fusion is often unnecessary in patients with degenerative spondylolisthesis and lumbar stenosis if the posterior decompression technique is unilateral laminotomy with bilateral decompression.
  
  
  METHODS
  2.
authors.affiliation: From the Department of Neurosurgery, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan.
authors.forename: Han Soo
authors.initials: HS
authors.lastname: Chang
authors.forename: Naoaki
authors.initials: N
authors.lastname: Fujisawa
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Tsuchiya
authors.forename: Soichi
authors.initials: S
authors.lastname: Oya
authors.forename: Toru
authors.initials: T
authors.lastname: Matsui
mesh_terms: D000368:Aged; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007796:Laminectomy / Q000379:methods*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010147:Pain Measurement; D011446:Prospective Studies; D011859:Radiography; D013130:Spinal Stenosis / Q000150:complications / Q000601:surgery*; D013168:Spondylolisthesis / Q000150:complications / Q000601:surgery*; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome