title: Reduction of high-grade spondylolisthesis using Edwards instrumentation.
abstract: METHODS
  Sixteen patients with high-grade spondylolisthesis (Grade III or higher) who underwent posterior decompression and reduction using the Edwards Modular Spine System (Spinal System Ltd., Baltimore, MD) were reviewed clinically and radiographically.
  
  
  OBJECTIVE
  This study was undertaken to determine the efficacy of one specific reduction technique to treat patients with high-grade spondylolisthesis where there has been a loss of sagittal balance, intractable pain, and/or neurologic deficit.
  
  
  BACKGROUND
  The average age of our patients was 20 years. Preoperative slippage averaged 89%; preoperative slip angle averaged 50 degrees. Indications for surgery were back and leg pain, progression of slippage (in 9 patients), and/or the inability to stand upright with the knees straight.
  
  
  METHODS
  Pre- and postoperative radiographic films were reviewed. The percent slip and the slip angle were measured pre- and postoperatively. Clinical data were obtained via chart review, telephone interview, and/or office visit.
  
  
  RESULTS
  The average preoperative slip was 89%; postoperatively, the average slip was 29%. Slip angle averaged 50 degrees preoperatively and improved to a postoperative average of 24 degrees. Three patients had neurologic impairment postoperatively; one did not resolve. Four patients had hardware failure; all were revised. Ten patients had an excellent result, 5 patients had a good result, and 1 patient had a fair result. The average follow-up was 3.8 years.
  
  
  CONCLUSIONS
  This procedure is technically demanding and is subject to the known risks of surgical treatment for high-grade spondylolisthesis. For select patients, it may be effective for reducing severe deformity and can be expected to afford good to excellent results. Improved sacral fixation may reduce the rate of hardware-related complications.
authors: University of California, San Francisco, USA.
authors: S S
authors: SS
authors: Hu
authors: D S
authors: DS
authors: Bradford
authors: E E
authors: EE
authors: Transfeldt
authors: M
authors: M
authors: Cohen
mesh_terms: D000293:Adolescent; D000328:Adult; D001863:Bone Screws; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017116:Low Back Pain / Q000209:etiology*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D009422:Nervous System Diseases / Q000209:etiology; D011859:Radiography; D012086:Reoperation; D012447:Sacrum / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation*; D013168:Spondylolisthesis / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome