title: Clinical characteristics and surgical outcome of thoracic myelopathy caused by ossification of the ligamentum flavum: a retrospective analysis of 85 cases.
abstract: METHODS
  A retrospective comparative study.
  
  
  OBJECTIVE
  To describe the clinical features and radiological findings, to assess the safety and effectiveness of posterior decompressive laminectomy and resection of the ossification of the ligamentum flavum (OLF), and to determine which presurgical and surgical variables were most closely related to postsurgical prognosis of thoracic myelopathy (TM) caused by OLF in China.
  
  
  METHODS
  Eighty-five patients with the diagnosis of TM caused by OLF received surgical treatment from July 1998 to May 2012. Clinical data were collected from medical and operative records. Correlations between the surgical outcome and various factors were also analyzed.
  
  
  RESULTS
  All cases were followed up for a mean of 49.2 months (range, 24-190 months) postoperatively. The mean Japanese Orthopaedic Association score was 3.8 points preoperatively and 8.2 points at the final follow-up, yielding a mean recovery rate of 63.0%. Postoperative complications included transient neurological deficits (9 cases), persistent neurological deficits (4 cases), dural tears (17 cases), cerebrospinal fluid leakage (9 cases), wound dehiscence (2 cases) and wound infection (3 cases). The OLF level (middle thoracic), preoperative duration of symptoms, intramedullary signal change on T2WI and preoperative severity of myelopathy were important predictors of surgical outcome.
  
  
  CONCLUSIONS
  Biomechanical and anatomical factors may have a key role in thoracic OLF progression. Posterior decompressive laminectomy and resection of the OLF can be considered an effective, reliable and safe alternative procedure. The OLF level, preoperative duration of symptoms, intramedullary signal change on T2WI and preoperative severity of myelopathy were confirmed and significantly correlated with the surgical outcome.
authors.affiliation: Department of Orthopaedics, First Affiliated Hospital of PLA General Hospital, Beijing, People's Republic of China.|Department of Orthopaedics, the 210 Hospital of Chinese PLA, Dalian, Liaoning Province, People's Republic of China.
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Orthopaedics, First Affiliated Hospital of PLA General Hospital, Beijing, People's Republic of China.
authors.forename: D
authors.initials: D
authors.lastname: Ren
authors.affiliation: Department of Orthopaedics, First Affiliated Hospital of PLA General Hospital, Beijing, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Orthopaedics, First Affiliated Hospital of PLA General Hospital, Beijing, People's Republic of China.
authors.forename: S
authors.initials: S
authors.lastname: Hou
authors.affiliation: Department of Orthopaedics, First Affiliated Hospital of PLA General Hospital, Beijing, People's Republic of China.
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Orthopedics, Tenth People's Hospital of TongJi University, Shanghai, People's Republic of China.
authors.forename: S
authors.initials: S
authors.lastname: Yu
authors.affiliation: Department of Orthopedics, Tenth People's Hospital of TongJi University, Shanghai, People's Republic of China.
authors.forename: T
authors.initials: T
authors.lastname: Hou
mesh_terms: D000328:Adult; D000368:Aged; D019299:Decompression, Surgical; D005260:Female; D006801:Humans; D007796:Laminectomy; D017843:Ligamentum Flavum / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000473:pathology* / Q000601:surgery; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D013118:Spinal Cord Diseases / Q000473:pathology* / Q000601:surgery*; D013904:Thoracic Vertebrae; D016896:Treatment Outcome