title: Surgical strategy for cervical myelopathy due to ossification of the posterior longitudinal ligament: Part 1: Clinical results and limitations of laminoplasty.
abstract: METHODS
  Retrospective study of 66 patients who underwent laminoplasty for treatment of cervical myelopathy due to ossification of the posterior longitudinal ligament (OPLL).
  
  
  OBJECTIVE
  The present study describes surgical results of laminoplasty for treatment of cervical myelopathy due to OPLL and aims to clarify 1) factors predicting outcome and 2) limitations of laminoplasty.
  
  
  BACKGROUND
  During the period 1986 and 1996, laminoplasty was the only surgical treatment selected for cervical myelopathy at our institutions.
  
  
  METHODS
  We reviewed data obtained in 66 patients who underwent laminoplasty for treatment of cervical myelopathy due to OPLL. Mean duration of follow-up was 10.2 years (range, 5-20 years). Surgical outcomes were assessed using the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy.
  
  
  RESULTS
  Surgical outcome was significantly poorer in patients with occupying ratio greater than 60%. Multiple regression analysis showed that the most significant predictor of poor outcome after laminoplasty was hill-shaped ossification, followed by lower preoperative JOA score, postoperative change in cervical alignment, and older age at surgery.
  
  
  CONCLUSIONS
  Laminoplasty is effective and safe for most patients with occupying ratio of OPLL less than 60% and plateau-shaped ossification. However, neurologic outcome of laminoplasty for cervical OPLL was poor or fair in patients with occupying ratio greater than 60% and/or hill-shaped ossification.
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. iwasaki@ort.med.osaka-u.ac.jp
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Shin'ya
authors.initials: S
authors.lastname: Okuda
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sakaura
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Mukai
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yonenobu
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan; D007796:Laminectomy; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D011237:Predictive Value of Tests; D011859:Radiography; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome