A multicenter, prospective, non-randomized, historically controlled study. To demonstrate the Synergy Disc is at least as safe and effective as conventional anterior cervical discectomy and fusion (ACDF) to treat cervical degenerative disc disease (DDD) in subjects who are symptomatic at two levels from C3 to C7 are and are unresponsive to conservative management. Patients will be evaluated preoperatively, at the time of surgery, and at 6 weeks, and 3, 6, 12, and 24 months after surgery. Follow-up will continue annually until the last patient reaches 24-month follow-up. The primary analysis will occur at 24 months.

This is a research study comparing two ways of treating neck problems caused by degenerative disc disease (wear-and-tear damage to the discs that cushion the bones in the neck).

The study is comparing:

The Synergy Disc - an artificial disc device being studied in this trial, and Standard surgery (ACDF) - a widely used procedure called anterior cervical discectomy and fusion, which is the accepted current treatment.

Up to 200 people will receive the Synergy Disc as part of this study. Their results will be compared to results from people who had the standard ACDF surgery in the past, rather than assigning some people to get ACDF during this study (this is called a "historical control"). The study takes place at multiple medical centers.

Who this study is for:

People who are fully grown (skeletally mature) and have damage in two neighboring discs in the neck (located somewhere between the C3 and C7 vertebrae). To qualify, a person's symptoms must include:

Arm pain and/or nerve-related weakness or numbness (radiculopathy) that hasn't improved, and Neck pain or signs of spinal cord compression (myelopathy)

These symptoms must be caused by problems in the two affected disc levels, and must not have gotten better with non-surgical treatment (such as physical therapy, medication, or injections).

What the study will measure:

Whether the Synergy Disc is as safe and effective as standard ACDF surgery for people who need surgery to relieve pressure on the nerves or spinal cord at two neighboring disc levels in the neck.

Inclusion Criteria:

In order to be eligible to participate in this study, subjects must meet all of the following criteria:

1. Must be at least 18 years of age and be skeletally mature at the time of surgery
2. Has a preoperative neck pain score ≥ 8 (out of 20) based on the preoperative Neck and Arm Pain Questionnaire.
3. Has cervical degenerative disc disease at two (2) adjacent cervical levels (from C3 - C7) requiring surgical treatment and involving intractable radiculopathy, myelopathy, or both;
4. Has a herniated disc and/or osteophyte formation at each level to be treated that is producing symptomatic nerve root and/or spinal cord compression. The condition is documented by patient history (e.g., neck pain with arm pain, functional deficit and/or neurological deficit), and the requirement for surgical treatment is evidenced by radiographic studies (e.g., CT, MRI, x-rays, etc.);
5. Neck Disability Index (NDI) score ≥ 30/100 (raw score of ≥ 15/50);
6. Has been unresponsive to non-operative treatment for at least six weeks or has the presence of progressive symptoms or signs of nerve root/spinal cord compression in the face of continued non-operative management; has no previous surgical intervention at the involved levels or any subsequent planned/staged surgical procedure at the involved or adjacent level(s);
7. If a female of childbearing potential, patient is non-pregnant, non-nursing, and agrees not to become pregnant during the study period;
8. Is willing to comply with the study plan and sign the Patient Informed Consent Form

Exclusion Criteria:

Subjects who meet any of the following criteria will be excluded from participation in this study:

1. Has a cervical spinal condition other than symptomatic cervical DDD requiring surgical treatment at the involved levels;

2. Has documented or diagnosed cervical instability relative to adjacent segments at either level, defined by dynamic (flexion/extension) radiographs showing:

   1. Sagittal plane translation > 3.5 mm, or
   2. Sagittal plane angulation > 20°;

3. Prior attempted or completed cervical spine surgery, except (1) laminoforaminotomy (greater than 6 months prior to scheduled surgical treatment), which includes removal of disc material necessary to perform a nerve root decompression, with less than one-third facetectomy at any level, or (2) a successful single-level anterior cervical fusion (greater than 6 months prior to scheduled surgical treatment);

4. Has severe pathology of the facet joints of the involved vertebral bodies;

5. Axial neck pain only (no radicular or myelopathy symptoms);

6. Has been previously diagnosed with osteomalacia;

7. Osteoporosis: A screening questionnaire for osteoporosis, SCORE (Simple Calculated Osteoporosis Risk Estimation) for females or MORES for males (Male Osteoporosis Risk Estimation Score), will be used to screen patients to determine those patients who require a DXA of the hip, a bone mineral density measurement. A SCORE or MORES ≥6 requires a DXA. If DXA is required, exclusion will be defined as a DXA bone density measured T score ≤ -2.5 (The World Health Organization definition of osteoporosis). DXA scans within the last 6 months prior to surgical treatment may be used;

8. Has presence of spinal metastases;

9. Has overt or active bacterial infection, either local or systemic;

10. Has insulin-dependent diabetes;

11. Has chronic or acute renal failure or prior history of renal disease;

12. Known titanium or UHMWPE allergy;

13. Is mentally incompetent (if questionable, obtain psychiatric consult);

14. Is a prisoner;

15. Is pregnant ;

16. Is currently an alcohol and/or drug abuser or currently undergoing treatment for alcohol and/or drug abuse;

17. Is involved with current or pending litigation regarding a spinal condition;

18. Has received drugs that may interfere with bone metabolism within two weeks prior to the planned date of spinal surgery (e.g., steroids or methotrexate), excluding routine perioperative anti-inflammatory drugs;

19. Has a history of an endocrine or metabolic disorder known to affect osteogenesis (e.g., Paget's Disease, renal osteodystrophy, Ehlers-Danlos Syndrome, or osteogenesis imperfecta);

20. Has a condition that requires postoperative medications that interfere with the stability of the implant, such as steroids. This does not include low-dose aspirin for prophylactic anticoagulation and routine perioperative anti-inflammatory drugs;

21. Has received treatment with an investigational therapy within 28 days prior to implantation surgery or such treatment is planned during the 16 weeks following implantation