title: Results of instrumented posterolateral fusion in treatment of lumbar spondylolisthesis with and without segmental kyphosis: A retrospective investigation.
abstract: BACKGROUND
  Treatment by posterolateral fusion (PLF) with pedicle-screw instrumentation can be unsuccessful in one-segment and low-grade lumbar spondylolisthesis. Segmental kyphosis, either rigid or dynamic, was hypothesized to be one of the factors interfering with the fusion results.
  
  
  METHODS
  From 2004 to 2005, 239 patients with single-segment and low-grade spondylolisthesis were recruited and divided into two groups: Group 1 consisting of 129 patients without segmental kyphosis and group 2 consisting of 110 patients with segmental kyphosis. All patients underwent instrumented PLF at the same medical institute, and the average follow-up period was 31 ± 19 months. We obtained plain radiographs of the lumbosacral spine with the anteroposterior view, the lateral view, and the dynamic flexion-extension views before the operation and during the follow-ups. The results of PLF in the two groups were then compared.
  
  
  RESULTS
  There was no significant difference in the demographic data of the two groups, except for gender distribution. The osseous fusion rates were 90.7% in group 1 and 68.2% in group 2 (p < 0.001).
  
  
  CONCLUSIONS
  Instrumented PLF resulted in significantly higher osseous fusion rate in patients without segmental kyphosis than in the patients with segmental kyphosis. For the patients with sagittal imbalance, such as rigid or dynamic kyphosis, pedicle-screw fixation cannot ensure successful PLF. Interbody fusion by the posterior lumbar interbody fusion or transforaminal lumbar interbody fusion technique might help overcome this problem.
authors.forename: Szu-Yuan
authors.initials: SY
authors.lastname: Chen
authors.forename: Meng-Ling
authors.initials: ML
authors.lastname: Lu
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Chi-Chien
authors.initials: CC
authors.lastname: Niu
authors.forename: Tsung-Ting
authors.initials: TT
authors.lastname: Tsai
authors.forename: Jen-Chung
authors.initials: JC
authors.lastname: Liao
authors.forename: Lih-Huei
authors.initials: LH
authors.lastname: Chen
authors.forename: Wen-Jer
authors.initials: WJ
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D001863:Bone Screws; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008161:Lumbosacral Region / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular / Q000502:physiology; D012189:Retrospective Studies; D013168:Spondylolisthesis / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome