title: Eight-year clinical and radiological follow-up of the Bryan cervical disc arthroplasty.
abstract: METHODS
  Single institution, prospective cohort study of 21 patients who underwent single- or bilevel cervical disc arthroplasty for radiculopathy.
  
  
  OBJECTIVE
  To evaluate the long-term outcome of cervical disc arthroplasty.
  
  
  BACKGROUND
  There is an increasing trend in the use of cervical arthroplasty; however, no long-term outcome studies exist to verify their safety, functionality, and durability.
  
  
  METHODS
  A total of 21 patients underwent 27 total disc arthroplasties using the Bryan cervical disc (Medtronic Sofamor Danek Inc, Memphis, TN) after anterior cervical discectomy. Clinical and radiological data were obtained from the 8-year postoperative review.
  
  
  RESULTS
  Nineteen of twenty-one patients were able to perform daily activities without limitation. Twenty of twenty-one patients reported fair to excellent outcome according to Odom criteria and 21 of 27 (78%) operated segments were mobile. Functional prostheses moved an average of 10.6°, which was similar to the range of movement of the adjacent nonoperated segments of the cervical spine. Heterotopic ossification was evident in 13 of the 27 (48%) operated segments and restricted movement of the prosthesis in nine cases. Five of the six patients who received bilevel arthroplasties developed heterotopic ossification. There was one case of posterior migration of the prosthesis, which did not have any clinical repercussion. No other case showed evidence of migration, subsidence, loosening, or wear. Radiological evidence of adjacent segment degeneration was observed in four patients (19%); however, each of these patients had pre-existing degenerative disc disease at these levels on preoperative imaging.
  
  
  CONCLUSIONS
  At 8-year follow-up, the Bryan cervical disc arthroplasty maintains favorable clinical and radiological results, with preservation of movement and satisfactory clinical outcome in the majority of cases. However, the incidence of heterotopic ossification causing restricted range of movement of the prosthesis appears to increase with time, especially in bilevel procedures.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital of Bordeaux, Bordeaux, France.
authors.forename: Gerald M Y
authors.initials: GM
authors.lastname: Quan
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Vital
authors.forename: Steve
authors.initials: S
authors.lastname: Hansen
authors.forename: Vincent
authors.initials: V
authors.lastname: Pointillart
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001178:Arthroplasty / Q000379:methods*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011843:Radiculopathy / Q000601:surgery*; D011859:Radiography; D016059:Range of Motion, Articular; D013997:Time Factors; D016896:Treatment Outcome