Core herniation after implantation of a cervical artificial disc: case report

Introduction Cervical artificial discs (CADs) represent an established surgical option in selected patients with cervical spinal disc degeneration. Though CADs have been available for many years, there is a lack of information concerning long-term safety, durability and implant-related failure rates. Materials and methods The authors describe the failure of a M6-C CAD (Spinal Kinetics, Sunnyvale, CA, USA). Results Eight years after implantation of a CAD of the M6 type, a 39-year-old female presented with new clinical signs of cervical myelopathy. Radiologically, medullar compression due to posterior core herniation was the suspected cause. The damaged CAD was removed and the segment fused. During revision surgery, rupture of the posterior structures could be detected. Possible mechanisms leading to implant failure are discussed. Conclusion As there is no standard regarding clinical and radiological follow-up for patients with CADs, radiological long-term follow-up investigations seem to be justified for exclusion of implant failure.