The M6-C Post Approval Study is a long term follow-up study of subjects previously enrolled and treated in the M6-C Artificial Cervical Disc IDE Study.

A prospective, concurrently controlled, multi-center pivotal study to evaluate the safety and effectiveness of the M6-C™ Artificial Cervical Disc compared to anterior cervical discectomy and fusion (ACDF) was performed in the United States under IDE #G050254. To fulfill the concurrent control design of the study, there were clinical sites that evaluated the safety and effectiveness of the M6-C™ Artificial Cervical Disc and there were other clinical sites that evaluated ACDF. Subjects in the study were treated between May 2014 and June 2016 and remain in follow-up. The M6-C™ Artificial Cervical Disc received FDA approval to market on February 6, 2019. As a condition of approval, the FDA requested that the sponsor perform a post market approval study (PAS). The subjects enrolled and remaining in the M6-C IDE pivotal study are the prospective patient population for the PAS.

Inclusion Criteria:

• Since the subjects have already been screened as part of the IDE's pivotal study, and only subjects that participated in that study make up the subject cohort for this long-term follow-up study, there are no additional inclusion criteria

Exclusion Criteria:

• Subjects who were withdrawn or withdrew consent to participate in the investigation
• Subjects who do not consent to participate in long-term follow-up or provide personal contact information to the sponsor (solely for the purposes of tracking subjects to help ensure follow-up compliance)
• Patients with terminal failures (SSI or device- or procedure-related SAE) by Month 24 and all known patient deaths in the M6-C IDE study are excluded for enrollment into the PAS

Subjects eligible for study enrollment will include subjects implanted in the M6-C™ IDE pivotal study