title: Comparative Study of Surgical Treatment and Nonsurgical Follow Up for Thoracic Ossification of the Posterior Longitudinal Ligament: Radiological and Clinical Evaluation.
abstract: METHODS
  A prospective clinical study of factors related to myelopathy deterioration caused by thoracic myelopathy because of ossification of the posterior longitudinal ligament (T-OPLL).
  
  
  OBJECTIVE
  The objective of the study was to investigate factors related to myelopathy deterioration caused by T-OPLL.
  
  
  BACKGROUND
  Detailed analyses of factors related to myelopathy deterioration caused by T-OPLL have not been reported.
  
  
  METHODS
  Twenty-two patients (group O) received observation therapy because of the absence of or mild myelopathy, which was defined as walking unaided or with support, and a Japanese Orthopedic Association (JOA) score above 7 points; and 24 patients (group S) were treated with posterior decompression and fusion with instrumentation. Age, sex, body mass index (BMI), presence of diabetes mellitus (DM), and JOA score were obtained for all patients. Radiologically, the T-OPLL level, number of T-OPLLs, canal diameter ratio (CDR), morphology, ossification of the ligamentum flavum (OLF), and cervical OPLL were examined on reconstructed CT, and the presence of hyperintense areas (HIAs) on T2-weighted sagittal MR images.
  
  
  RESULTS
  In total, the patients included 22 males and 24 females and had an age range from 18 to 80 years. Sex, DM, JOA score in each domain, OPLL location, OPLL number, CDR of OPLL, morphology, OLF, and cervical OPLL did not differ significantly between groups N and S. However, cases in group N had a significantly higher age, lower weight, lower BMI, lower discontinuous rate on sagittal CT, and a lower HIA rate on MRI. Postoperatively, discontinuous segments connected and became continuous across the disc space in all patients in group S without progression of OPLL thickness.
  
  
  CONCLUSIONS
  Age, weight, BMI, discontinuity between rostral and caudal OPLL lesions, and occurrence of a high intensity area on MRI are likely to be associated with development of myelopathy.
  
  
  METHODS
  3.
authors.affiliation: Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya-city, Aichi, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Ando
authors.forename: Shiro
authors.initials: S
authors.lastname: Imagama
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Hida
authors.forename: Kenyu
authors.initials: K
authors.lastname: Ito
authors.forename: Mikito
authors.initials: M
authors.lastname: Tsushima
authors.forename: Yoshimoto
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Akiyuki
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nishida
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
mesh_terms: D000368:Aged; D002574:Cervical Vertebrae / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017846:Longitudinal Ligaments / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000000981:diagnostic imaging* / Q000601:surgery; D010012:Osteogenesis / Q000502:physiology*; D011446:Prospective Studies; D011871:Radiology / Q000379:methods; D013118:Spinal Cord Diseases / Q000601:surgery; D013904:Thoracic Vertebrae / Q000601:surgery*; D016896:Treatment Outcome