title: The modified Japanese Orthopaedic Association scale: establishing criteria for mild, moderate and severe impairment in patients with degenerative cervical myelopathy.
abstract: We aimed to determine cut-offs between mild, moderate and severe myelopathy on the modified Japanese Orthopedic Association (mJOA) score.
  
  
  
  Between December 2005 and January 2011, 757 patients with clinically diagnosed DCM were enrolled in the prospective AOSpine North America (n = 278) or International (n = 479) study at 26 sites. Functional status and quality of life were evaluated at baseline using a variety of outcome measures. Using the Nurick score as an anchor, receiver operating curve (ROC) analysis was conducted to determine cut-offs between mild, moderate and severe disease. The validity of the identified cut-offs was evaluated by examining whether patients in different severity groups differed in terms of impairment, disability, quality of life and number of signs and symptoms.
  
  
  
  A mJOA of 14 was determined to be the cut-off between mild and moderate myelopathy and a mJOA of 11 was the cut-off score between moderate and severe disease. Patients in the severe myelopathy group (n = 254) had significantly reduced quality of life and functional status and a greater number of signs and symptoms compared to patients classified as mild (n = 190) or moderate (n = 296).
  
  
  
  Mild myelopathy can be defined as mJOA from 15 to 17, moderate as mJOA from 12 to 14 and severe as mJOA from 0 to 11. These categories should be adopted worldwide to standardize clinical assessment of DCM.
authors.affiliation: Division of Neurosurgery and Spinal Program, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst St. Suite 4WW-449, Toronto, ON, M5T 2S8, Canada.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Tetreault
authors.affiliation: Department of Health Services, University of Washington, Seattle, WA, USA.
authors.forename: Branko
authors.initials: B
authors.lastname: Kopjar
authors.affiliation: Division of Neurosurgery and Spinal Program, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst St. Suite 4WW-449, Toronto, ON, M5T 2S8, Canada.
authors.forename: Aria
authors.initials: A
authors.lastname: Nouri
authors.affiliation: Department of Neurosurgery, University of Kansas, Kansas City, KS, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Arnold
authors.affiliation: Department of Neurosurgery, University Hospital Catania, Catania, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Barbagallo
authors.affiliation: Department of Neurosurgery, Nijmegen Medical Centre, Radboud University, Nijmegen, The Netherlands.
authors.forename: Ronald
authors.initials: R
authors.lastname: Bartels
authors.affiliation: Department of Orthopaedics, Southwest Hospital, Third Military Medical University, Chongqing, People's Republic of China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Qiang
authors.affiliation: Division of Neurosurgery and Spinal Program, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst St. Suite 4WW-449, Toronto, ON, M5T 2S8, Canada.
authors.forename: Anoushka
authors.initials: A
authors.lastname: Singh
authors.affiliation: Department of Neurosurgery, Ege University Faculty of Medicine, Izmir, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Zileli
authors.affiliation: Department of Orthopaedic Surgery, Sidney Kimmel Medical Center at Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Vaccaro
authors.affiliation: Division of Neurosurgery and Spinal Program, Department of Surgery, Toronto Western Hospital, University of Toronto, 399 Bathurst St. Suite 4WW-449, Toronto, ON, M5T 2S8, Canada. michael.fehlings@uhn.ca.
authors.forename: Michael G
authors.identifier: 0000-0002-5722-6364
authors.initials: MG
authors.lastname: Fehlings
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000503:physiopathology*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D013122:Spinal Diseases / Q000503:physiopathology*; D055815:Young Adult
keywords: Defining disease severity; Degenerative cervical myelopathy; Functional impairment; Measurement; Modified Japanese Orthopaedic Association scale