Delayed Failure of M6-C Cervical Disc Arthroplasty After Conversion of Adjacent Cervical Disc Arthroplasty to Fusion: A Case Report.

This is the first report of M6-C failure after conversion of an adjacent arthroplasty to fusion. A growing number of reports surrounding the M6-C failure rate and mechanisms raise concern about the device's durability and underscore the importance of routine clinical and radiographic surveillance for these patients.