Cervical Interbody Implant Study

Inclusion Criteria: 1. Patients who are ≥18 years of age at the time of consent 2. Have a planned spine surgery using interbody implants at one or more cervical levels (C2-T1) for degenerative disc disease and/or cervical spinal instability 3. Using one of the following implants (NuVasive, Inc., San Diego, CA): 1. Cohere Cervical 2. Modulus Cervical 4. With interbody fusion using autograft and/or allograft (i.e., cancellous and/or corticocancellous allograft bone) and NuVasive supplemental internal fixation cleared by the applicable regulatory body for use in the cervical spine 5. Able to undergo surgery based on physical exam, medical history, and surgeon judgment 6. Understands the conditions of enrollment, is willing to follow medical advice including postoperative activity restrictions per the surgeon's standard of care, and is willing to sign an informed consent form to participate in the study Exclusion Criteria: 1. Use of any bone graft that is not cleared by the applicable regulatory body for use within interbody implants. Examples of these include: 1. Bone morphogenic protein (BMP) (i.e., Infuse (Medtronic)) 2. Synthetic bone graft extenders (e.g., Formagraft (NuVasive), Mastergraft (Medtronic), Vitoss (Stryker), Actifuse (Baxter), nanOss (RTI Surgical), Fibergraft (Prosidyan/Depuy Synthes), and ChronOs (Depuy Synthes)) 3. Demineralized bone matrices (DBM) regulated as medical devices by the FDA (e.g., Grafton Putty/Gel (Medtronic), DBX (MTF/Depuy Synthes), Accell Evo3 (IsoTis), and Propel Putty/Gel (NuVasive)) 4. Peptide enhanced bone graft (e.g., iFactor (Cerapedics)) 2. Previous cervical fusion surgery at the level(s) to be treated (adjacent level surgery is acceptable; prior decompression is acceptable) 3. Patient is involved in active litigation relating to the spine (worker's compensation claim is allowed if it is not contested) 4. Use of bone growth stimulators postoperatively 5. Active smoking within 6 weeks before surgery 6. Patient has known sensitivity to the materials implanted 7. Systemic or local infection (latent or active) or signs of local inflammation 8. Patient has inadequate bone stock or bone quality, or a physical or medical condition that would prohibit beneficial surgical outcome based on surgeon judgment 9. Patient is a prisoner 10. Patient is participating in another clinical study that would confound study data