title: A clinical analysis of 4- and 6-year follow-up results after cervical disc replacement surgery using the Bryan Cervical Disc Prosthesis.
abstract: OBJECTIVE
  In this study, long-term results are presented from clinical studies of the Bryan Cervical Disc Prosthesis at University Hospital Gasthuisberg in Leuven, Belgium. A total of 98 patients (89 with 1-level and 9 with 2-level implantations) agreed to participate in follow-up studies for up to 10 years postoperatively. This article focuses on the 4- and 6-year results. Patients in one of the clinical studies had either radiculopathy or myelopathy associated with spondylosis and/or disc herniations that did not respond to conservative treatment. Patients from the other clinical study received commercially available Bryan devices and the study protocol did not have specific inclusion/exclusion criteria. More than 90% of the patients were considered to have radiculopathy.
  
  
  METHODS
  Clinical measurements discussed in the article include the 36-Item Short Form Health Survey, Neck Disability Index, numerical ratings of neck and arm pain, neurological outcomes, and Odom classification. Angular motion findings from lateral flexion-extension radiographs are also presented. The occurrence of adverse events and second surgeries are examined as an indicator of device safety.
  
  
  RESULTS
  The clinical outcomes at 4 and 6 years postoperatively appear consistent with the previously reported results at 1 and 2 years postoperatively. The mean angular motion results at 4 and 6 years postoperatively for 1-level patients were 7.3 and 7.7 degrees, respectively. Two-level patients had slightly less motion at 4 and 6 years postoperatively with mean caudad values of 5.7 and 6.0 degrees, respectively, and cephalad values of 4.2 and 6.2 degrees, respectively. Efforts were made to capture adverse events, regardless of their nature and relatedness to the study surgery. This effort resulted in a relatively high number of recorded events. However, only 6 patients experienced events that were judged by the investigator to be related, either possibly or definitely, to the Bryan device. These events included device migration, device removal, and hoarseness and vocal cord paralysis, as well as 3 cases involving pain and neurological symptoms. Eight patients underwent further neck surgery to treat symptoms.
  
  
  CONCLUSIONS
  The favorable clinical and angular motion outcomes that were previously noted at 1- and 2-years' follow-up after cervical disc replacement with the Bryan Cervical Disc Prosthesis appear to persist after 4 and 6 years of follow-up.
authors.affiliation: Department of Neurosurgery, Catholic University of Leuven, Belgium. neurochirurgie@uzleuven.be
authors.forename: Jan
authors.initials: J
authors.lastname: Goffin
authors.forename: Johan
authors.initials: J
authors.lastname: van Loon
authors.forename: Frank
authors.initials: F
authors.lastname: Van Calenbergh
authors.forename: Bailey
authors.initials: B
authors.lastname: Lipscomb
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000601:surgery*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery*; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000009:adverse effects / Q000295:instrumentation; D019736:Prostheses and Implants / Q000009:adverse effects; D019919:Prosthesis Implantation / Q000009:adverse effects; D011843:Radiculopathy / Q000601:surgery*; D013118:Spinal Cord Diseases / Q000601:surgery*; D055009:Spondylosis / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome