title: Clinical features and surgical outcomes of patients with thoracic myelopathy caused by multilevel ossification of the ligamentum flavum.
abstract: BACKGROUND
  Thoracic myelopathy caused by multilevel (three or more levels) ossification of the ligamentum flavum (OLF) is rare. Little is known about its clinical features, and the surgical outcomes along with its related factors are also unclear.
  
  
  OBJECTIVE
  To describe the clinical features, assess the safety and effectiveness of surgical decompression, and determine the prognostic factors relevant for patients with thoracic myelopathy caused by multilevel OLF.
  
  
  METHODS
  A retrospective clinical study.
  
  
  METHODS
  Seventy-five consecutive multilevel OLF patients who underwent surgical decompression were analyzed.
  
  
  METHODS
  Modified Japanese Orthopedic Association (JOA) scale and the recovery rate.
  
  
  METHODS
  Patients who underwent surgical decompression for symptomatic multilevel OLF during January 1996 to June 2010 were all included. Clinical data were collected from medical and operative records; patients were evaluated by using the JOA scale preoperatively and during the follow-up. Correlations between the surgical outcome and various factors were also analyzed.
  
  
  RESULTS
  Forty-three men and 32 women with a mean age of 54.7 years (range 36-78 years) were included. The mean number of involved levels is 4.6 and contiguous OLF presented in 73.3% of these patients. The most common involved levels were T10/T11 (15.4%), T9/T10 (13.3%), and T11/T12 (12.5%). Coexisting spinal disorders were found in 41 patients (54.7%). Preoperative evaluation showed the mean JOA score was 5.8±1.7; 37.3% of these patients had mild myelopathy, 53.3% had moderate myelopathy, and 9.3% had severe myelopathy. All patients received posterior laminectomy. The JOA score (mean 8.2±2.1) significantly increased postoperatively (p<.05), and multiple regression analysis showed that preoperative duration of symptoms and preoperative JOA score were important predictors of surgical outcome.
  
  
  CONCLUSIONS
  Laminectomy with partially internal fixation is safe and effective in treatment of patients with symptomatic multilevel OLF. The results of our study show that preoperative JOA score and preoperative duration of symptoms were important predictors for the clinical outcome.
authors.affiliation: Department of Spine Surgery, Changzheng Hospital, Second Military Medical University, 415 Fengyang Rd, Shanghai 200003, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Gao
authors.forename: Wen
authors.initials: W
authors.lastname: Yuan
authors.forename: Lili
authors.initials: L
authors.lastname: Yang
authors.forename: Guodong
authors.initials: G
authors.lastname: Shi
authors.forename: Lianshun
authors.initials: L
authors.lastname: Jia
mesh_terms: D000328:Adult; D000368:Aged; D019299:Decompression, Surgical / Q000379:methods; D005260:Female; D006801:Humans; D017843:Ligamentum Flavum / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000150:complications / Q000473:pathology* / Q000601:surgery*; D012189:Retrospective Studies; D013118:Spinal Cord Diseases / Q000209:etiology*; D013904:Thoracic Vertebrae; D016896:Treatment Outcome
keywords: Clinical outcome; Laminectomy; Ossification of the ligamentum flavum (OLF); Thoracic myelopathy