title: Risk factors of radiological adjacent disc degeneration with lumbar interbody fusion for degenerative spondylolisthesis.
abstract: BACKGROUND
  Although various risk factors have been reported for adjacent segment degeneration after lumbar fusion, the exact mechanisms and risk factors related to adjacent segment degeneration have not been clear. The present study was conducted to evaluate the risk factors for radiological adjacent segment degeneration in patients surgically treated for single-level L4 spondylolisthesis focusing on a single pathology, a specific fusion level, at a set interval.
  
  
  METHODS
  We assessed preoperative and five-year postoperative radiographs for 72 patients who underwent L4-5 anterior or posterior lumbar interbody fusion for single-level L4 degenerative spondylolisthesis. Adjacent segment degeneration was defined as imaging evidence of one or more of the following conditions at L1-2, L2-3, or L3-4: 1) a loss of more than 20% of the preoperative disc height, 2) anterolisthesis or retrolisthesis greater than 3 mm, 3) or osteophyte formation greater than 3 mm.
  
  
  RESULTS
  We found adjacent segment degeneration in 21 patients, with 31 discs affected. Multiple logistic regression analysis identified the following significant independent risk factors for adjacent segment degeneration: female gender (odds ratio 10.80; 95% confidence interval 1.20-96.89), posterior lumbar interbody fusion (odds ratio 7.70; 95% confidence interval 1.82-32.66), and pre-existing disc degeneration (odds ratio 12.29; 95% confidence interval 1.69-89.27).
  
  
  CONCLUSIONS
  Female gender, posterior lumbar interbody fusion, and pre-existing disc degeneration were significant independent risk factors for radiologically diagnosed adjacent segment degeneration in patients treated for L4 degenerative spondylolisthesis by interbody lumbar fusion.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuji
authors.affiliation: Department of Advanced Treatment for Spine and Spinal Cord Disorders, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Kota
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Orthopaedic Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitame, 359-8513, Japan.
authors.forename: Naobumi
authors.initials: N
authors.lastname: Hosogane
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Fujita
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Department of Orthopaedic Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitame, 359-8513, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiba
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan. Electronic address: morio@a5.keio.jp.
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D005260:Female; D006801:Humans; D015994:Incidence; D055959:Intervertebral Disc Degeneration / Q000175:diagnosis* / Q000209:etiology; D007564:Japan / Q000453:epidemiology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis* / Q000453:epidemiology; D011859:Radiography / Q000379:methods*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013123:Spinal Fusion / Q000009:adverse effects*; D013168:Spondylolisthesis / Q000175:diagnosis / Q000601:surgery*