title: Medium-term clinical results of microsurgical lumbar flavectomy that preserves facet joints in cases of lumbar degenerative spondylolisthesis: comparison of bilateral laminotomy with bilateral decompression by a unilateral approach.
abstract: METHODS
  A retrospective study of medium-term results.
  
  
  OBJECTIVE
  To describe a technique for posterior decompression using microsurgical lumbar flavectomy (MLF) without facetectomy, which is based on the anatomic features of the ligamentum flavum, and to examine the clinical outcomes of patients with lumbar spinal spondylolisthesis with lower extremity symptoms rather than low back pain, who underwent this procedure by 2 different approaches.
  
  
  BACKGROUND
  Posterior decompression with fusion has been the optimal and standard operative treatment for lumbar degenerative spondylolisthesis. Alternatively, minimally invasive procedures have been used for the treatment of lumbar degenerative spondylolisthesis with favorable outcomes.
  
  
  METHODS
  A bilateral laminotomy (BL group) was performed on 44 consecutive patients, and bilateral decompression by a unilateral approach (BDU group) was performed on 23 consecutive patients. The mean follow-up period was 7.0 years. The Japanese Orthopaedic Association score and recovery rate were obtained, and radiographic assessment was performed using plain radiograms on the lateral view while standing in flexion, neutral, and extension postures before surgery and at the final follow-up.
  
  
  RESULTS
  The Japanese Orthopaedic Association score at the final follow-up was improved in the BL and BDU groups, compared with that before MLF. The mean recovery rate was 72.4% and 68.4%, respectively. The mean % slip increased at the final follow-up, compared with that before surgery in both groups, except for the % slip in the extension posture in the BDU group. However, there was no significant difference in the dynamic % slip in the flexion-extension posture between before surgery and at the final follow-up.
  
  
  CONCLUSIONS
  Clinical and radiologic parameters were not significantly different between the 2 groups. This technique of MLF using either approach did not increase the dynamic % slip and showed favorable medium-term clinical results in cases of lumbar degenerative spondylolisthesis.
authors.affiliation: *Department of Orthopaedic Surgery, Programs for Applied Biomedicine, Division of Clinical Medical Science, Graduate School of Biomedical Sciences, Hiroshima University †Department of Orthopaedic Surgery, Hiroshima General Hospital, Hiroshima, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tanaka
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujimoto
authors.forename: Teruaki
authors.initials: T
authors.lastname: Okuda
authors.forename: Naosuke
authors.initials: N
authors.lastname: Kamei
authors.forename: Toshio
authors.initials: T
authors.lastname: Nakamae
authors.forename: Bun-Ichiro
authors.initials: B
authors.lastname: Izumi
authors.forename: Ryo
authors.initials: R
authors.lastname: Ohta
authors.forename: Yuki
authors.initials: Y
authors.lastname: Fujioka
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019299:Decompression, Surgical / Q000379:methods*; D003710:Demography; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000379:methods*; D017843:Ligamentum Flavum / Q000000981:diagnostic imaging / Q000601:surgery*; D017116:Low Back Pain / Q000601:surgery; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D013123:Spinal Fusion / Q000379:methods; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging / Q000601:surgery*