title: Degenerative Cervical Myelopathy: Epidemiology, Genetics, and Pathogenesis.
abstract: METHODS
  Review.
  
  
  OBJECTIVE
  To formally introduce "degenerative cervical myelopathy" (DCM) as the overarching term to describe the various degenerative conditions of the cervical spine that cause myelopathy. Herein, the epidemiology, pathogenesis, and genetics of conditions falling under this hypernym are carefully described.
  
  
  BACKGROUND
  Nontraumatic, degenerative forms of cervical myelopathy represent the commonest cause of spinal cord impairment in adults and include cervical spondylotic myelopathy, ossification of the posterior longitudinal ligament, ossification of the ligamentum flavum, and degenerative disc disease. Unfortunately, there is neither a specific term nor a specific diagnostic International Classification of Diseases, Tenth Revision code to describe this collection of clinical entities. This has resulted in the inconsistent use of diagnostic terms when referring to patients with myelopathy due to degenerative disease of the cervical spine.
  
  
  METHODS
  Narrative review.
  
  
  RESULTS
  The incidence and prevalence of myelopathy due to degeneration of the spine are estimated at a minimum of 41 and 605 per million in North America, respectively. Incidence of cervical spondylotic myelopathy-related hospitalizations has been estimated at 4.04/100,000 person-years, and surgical rates seem to be rising. Pathophysiologically, myelopathy results from static compression, spinal malalignment leading to altered cord tension and vascular supply, and dynamic injury mechanisms. Occupational hazards, including transportation of goods by weight bearing on top of the head, and other risk factors may accelerate DCM development. Potential genetic factors include those related to MMP-2 and collagen IX for degenerative disc disease, and collagen VI and XI for ossification of the posterior longitudinal ligament. In addition, congenital anomalies including spinal stenosis, Down syndrome, and Klippel-Feil syndrome may predispose to the development of DCM.
  
  
  CONCLUSIONS
  Although DCMs can present as separate diagnostic entities, they are highly interrelated, frequently manifest concomitantly, present similarly from a clinical standpoint, and seem to be in part a response to compensate and improve stability due to progressive age and wear of the cervical spine. The use of the term "degenerative cervical myelopathy" is advocated.
  
  
  METHODS
  5.
authors.affiliation: *Division of Neurosurgery and Spine Program, Toronto Western Hospital, Toronto, Ontario, Canada †Toronto Western Research Institute and Krembil Neuroscience Center, University Health Network, Ontario, Canada; and ‡Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Aria
authors.initials: A
authors.lastname: Nouri
authors.forename: Lindsay
authors.initials: L
authors.lastname: Tetreault
authors.forename: Anoushka
authors.initials: A
authors.lastname: Singh
authors.forename: Spyridon K
authors.initials: SK
authors.lastname: Karadimas
authors.forename: Michael G
authors.initials: MG
authors.lastname: Fehlings
mesh_terms: D000818:Animals; D002574:Cervical Vertebrae / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D020022:Genetic Predisposition to Disease; D040941:Heredity; D006801:Humans; D015994:Incidence; D007587:Job Description; D008279:Magnetic Resonance Imaging; D009134:Muscular Atrophy, Spinal / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics* / Q000503:physiopathology / Q000601:surgery; D009784:Occupational Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics* / Q000503:physiopathology / Q000601:surgery; D009790:Occupations; D010375:Pedigree; D010641:Phenotype; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D012307:Risk Factors; D013122:Spinal Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics* / Q000503:physiopathology / Q000601:surgery; D009626:Terminology as Topic