title: Changes in sagittal alignment after restoration of lower lumbar lordosis in patients with degenerative flat back syndrome.
abstract: OBJECTIVE
  The authors investigate the correlation between thoracic and lumbar curves in patients with degenerative flat back syndrome, and demonstrate the predictability of spontaneous correction of the thoracic curve and sacral angle after surgical restoration of lower lumbar lordosis.
  
  
  METHODS
  The cases of 28 patients treated with combined anterior and posterior spinal arthrodesis were retrospectively reviewed. Inclusion criteria included loss of lower lumbar lordosis resulting in sagittal imbalance. Total lumbar lordosis, thoracic kyphosis, sacral slope, and C-7 plumb line length were measured on pre- and postoperative lateral views of the whole spine. Postoperative changes in thoracic kyphosis, sacral slope, and length of the C-7 plumb line were measured and evaluated according to extent of lumbar lordosis restoration.
  
  
  RESULTS
  The mean (+/- standard deviation) preoperative sagittal imbalance was 64.6 +/- 63.2 mm, which improved to 15.8 +/- 20.7 mm after surgery (p < 0.0001). The preoperative mean lumbar lordosis was 15.6 +/- 14.1 degrees, which increased to 40.3 +/- 14.5 degrees at follow-up (p < 0.0001). The preoperative mean thoracic kyphosis was 1.6 +/- 10.5 degrees and increased to 17.2 +/- 12.5 degrees at follow-up (p < 0.0001). Significant preoperative correlations existed between kyphosis and lordosis (r = 0.628, p = 0.0003), and between lordosis and sacral slope (r = 0.647, p = 0.0002). Postoperative correlations also existed between kyphosis and lordosis (r = 0.718, p < 0.0001 and r = 0.690, p < 0.0001, respectively).
  
  
  CONCLUSIONS
  Lower lumbar lordosis plays an important role in sagittal alignment and balance. Surgical restoration of lumbar lordosis results in predictable spontaneous correction of the thoracic curve and sacral slope in patients with degenerative flat back syndrome.
authors.affiliation: Department of Neurosurgery, Gimpo Airport Wooridul Spine Hospital, Seoul, Korea. spinejjs@yahoo.co.kr
authors.forename: Jee-Soo
authors.initials: JS
authors.lastname: Jang
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Jun-hong
authors.initials: JH
authors.lastname: Min
authors.forename: Dae Hyeon
authors.initials: DH
authors.lastname: Maeng
mesh_terms: D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D008159:Lumbar Vertebrae; D008875:Middle Aged; D011859:Radiography; D012074:Remission Induction; D012189:Retrospective Studies; D013123:Spinal Fusion; D013577:Syndrome; D013904:Thoracic Vertebrae; D016896:Treatment Outcome