title: Preoperative retrolisthesis as a risk factor of postdecompression lumbar disc herniation.
abstract: OBJECTIVE
  In this study, the authors aimed to identify specific risk factors for postdecompression lumbar disc herniation (PDLDH) in patients who have not undergone discectomy and/or fusion.
  
  
  METHODS
  Between 2007 and 2012, 493 patients with lumbar spinal stenosis underwent bilateral partial laminectomy without discectomy and/or fusion in a single hospital. Eighteen patients (herniation group [H group]: 15 men, 3 women; mean age 65.1 years) developed acute sciatica as a result of PDLDH within 2 years after surgery. Ninety patients who did not develop postoperative acute sciatica were selected as a control group (C group: 75 men, 15 women; mean age 65.4 years). Patients in the C group were age and sex matched with those in the H group. The patients in the groups were also matched for decompression level, number of decompression levels, and surgery date. The radiographic variables measured included percentage of slippage, intervertebral angle, range of motion, lumbar lordosis, disc height, facet angle, extent of facet removal, facet degeneration, disc degeneration, and vertebral endplate degeneration. The threshold for PDLDH risk factors was evaluated using a continuous numerical variable and receiver operating characteristic curve analysis. The area under the curve was used to determine the diagnostic performance, and values greater than 0.75 were considered to represent good performance.
  
  
  RESULTS
  Multivariate analysis revealed that preoperative retrolisthesis during extension was the sole significant independent risk factor for PDLDH. The area under the curve for preoperative retrolisthesis during extension was 0.849; the cutoff value was estimated to be a retrolisthesis of 7.2% during extension.
  
  
  CONCLUSIONS
  The authors observed that bilateral partial laminectomy, performed along with the removal of the posterior support ligament, may not be suitable for lumbar spinal stenosis patients with preoperative retrolisthesis greater than 7.2% during extension.
authors.affiliation: Orthopaedic Surgery, Japan Community Healthcare Organization Osaka Hospital, Osaka, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Takenaka
authors.affiliation: Orthopaedic Surgery, Japan Community Healthcare Organization Osaka Hospital, Osaka, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Tateishi
authors.affiliation: Orthopaedic Surgery, Japan Community Healthcare Organization Osaka Hospital, Osaka, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Hosono
authors.affiliation: Orthopaedic Surgery, Japan Community Healthcare Organization Osaka Hospital, Osaka, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Mukai
authors.affiliation: Orthopaedic Surgery, Japan Community Healthcare Organization Osaka Hospital, Osaka, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fuji
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019299:Decompression, Surgical / Q000379:methods; D017586:Diskectomy / Q000379:methods; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery*; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D007796:Laminectomy / Q000379:methods; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011300:Preoperative Care; D012307:Risk Factors; D013130:Spinal Stenosis / Q000601:surgery*; D013168:Spondylolisthesis / Q000601:surgery*; D016896:Treatment Outcome
keywords: AUC = area under the curve; BPL = bilateral partial laminectomy; DM = diabetes mellitus; ISL = interspinous ligament; JOA = Japanese Orthopaedic Association; LSS = lumbar spinal canal stenosis; PDLDH = postdecompression lumbar disc herniation; ROC = receiver operating characteristic; ROM = range of motion; SSL = supraspinous ligament; complication; disc herniation; laminectomy; lumbar; retrolisthesis