title: Comparison of Outcomes of Surgical Treatment for Ossification of the Posterior Longitudinal Ligament Versus Other Forms of Degenerative Cervical Myelopathy: Results from the Prospective, Multicenter AOSpine CSM-International Study of 479 Patients.
abstract: BACKGROUND
  Degenerative cervical myelopathy (DCM) is an all-encompassing term that includes cervical spondylotic myelopathy (CSM), ossification of the posterior longitudinal ligament (OPLL), and other spinal abnormalities that cause cervical cord compression. It is unclear whether surgery is equally effective and safe for patients with OPLL as it is for those with other forms of DCM. The purpose of this study was to compare surgical outcomes of patients with OPLL and those with other forms of DCM.
  
  
  METHODS
  Four hundred and seventy-nine patients with symptomatic DCM were prospectively enrolled in the CSM-International study at sixteen sites. Patients' functional status was evaluated using the modified Japanese Orthopaedic Association scale (mJOA) and the Nurick score. Quality of life was assessed using patient-reported outcome measures, including the Neck Disability Index (NDI) and the Short Form (SF)-36. Postoperative functional and quality-of-life outcomes were assessed at two years of follow-up, and scores were compared between patients with and without OPLL.
  
  
  RESULTS
  Of 479 patients, 135 (28.2%) had radiographic evidence of OPLL, and 344 (71.8%) had other forms of DCM. The two groups did not differ significantly in demographics, surgical approach, or baseline myelopathy severity. Patients with OPLL achieved similar functional outcomes by two years following surgery compared with patients with other forms of DCM. With respect to quality of life, the NDI and most of the subscales of the SF-36 were not different between the two diagnostic groups. There was a higher risk of perioperative complications in the OPLL group (p = 0.054), although this relationship did not reach statistical significance. Rates of neurological complications did not differ significantly between diagnostic groups.
  
  
  CONCLUSIONS
  Surgical decompression for the treatment of OPLL resulted in improvements in functional status and quality of life comparable to those seen in patients with other forms of DCM. Patients with OPLL were at a higher risk of perioperative complications than patients with other forms of DCM.
authors.affiliation: Division of Neurosurgery and Spinal Program, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakashima
authors.affiliation: Division of Neurosurgery and Spinal Program, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Tetreault
authors.affiliation: Division of Neurosurgery and Spinal Program, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Narihito
authors.initials: N
authors.lastname: Nagoshi
authors.affiliation: Division of Neurosurgery and Spinal Program, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Aria
authors.initials: A
authors.lastname: Nouri
authors.affiliation: Department of Neurosurgery, University of Kansas, Kansas City, Kansas.
authors.forename: Paul
authors.initials: P
authors.lastname: Arnold
authors.affiliation: Department of Orthopaedic Surgery, Chubu Rosai Hospital, Nagoya, Japan.
authors.forename: Yasutsugu
authors.initials: Y
authors.lastname: Yukawa
authors.affiliation: Department of Orthopaedic Surgery, Teikyo University School of Medicine, Tokyo, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Toyone
authors.affiliation: Department of Orthopedic Surgery, Okayama University, Okayama, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Orthopedics, Third Military Medical University, Chongqing, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Division of Neurosurgery and Spinal Program, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada Michael.Fehlings@uhn.on.ca.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Fehlings
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods; D017586:Diskectomy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007796:Laminectomy; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000601:surgery*; D011446:Prospective Studies; D011788:Quality of Life; D013123:Spinal Fusion; D055009:Spondylosis / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult