Comparison of Rigid and Non-Rigid Interbody Fusion Device for Cervical Degenerative Disc Disease in Adults

Comparison of Rigid and Non-Rigid Interbody Fusion Device for Cervical Degenerative Disc Disease in Adults - A Randomized, Prospective, Multicenter Clinical Trial

Rigid interbody fusion device in bulk configuration has been widely used in anterior cervical discectomy and fusion (ACDF) surgery. It is a randomized, prospective, multicenter clinical study to compare rigid and non-rigid fusion device in ACDF for cervical degenerative disc disease.

This study is a randomized, prospective, multicenter clinical trial comparing rigid (PEEK) interbody fusion device with non-rigid (Titanium Alloy, Z-Brace, Baui Biotech) interbody fusion device in ACDF surgery at 11 clinical sites. ACDF was performed with stand-alone interbody fusion device and artificial bone graft (hydroxyapatite/tricalcium phosphate). Patients have 1-level or 2-level cervical degenerative disc disease approved for ACDF surgery by National Health Insurance, which is the blind, third-party, administrative approved and insurance reimbursement for surgical indication. Total 180 patients were enrolled, and 180 patients were randomized into either investigational device (non-rigid) group or the control (rigid) group in a 2:1 ratio. After confirming a patient's eligibility and having the patient sign an informed consent form, the site investigator or study coordinator call the coordinator at National Taiwan University Hospital for the randomization. Each patient will be then assigned to 1 of the treatment group according to a randomized schedule. Patient were evaluated preoperatively, one month postoperatively, and 3, 6, 12, 18, and 24 months postoperatively. Measured outcomes included overall success, Neck Disability Index (NDI), VAS neck and arm pain, adjacent range of motion, patient satisfaction, anxiety score, SF-12 MCS/PCS, major complications, subsequent surgery rate, and subsidence and fusion rate on radiological examinations. The primary endpoint was a FDA composite definition of success comprising clinical improvement and absence of major complications and secondary surgery events.

Inclusion Criteria:

1. Age 20 - 69 years;
2. Symptomatic cervical degenerative disc disease in one or two levels between C3-7 with radiculopathy or myeloradiculopathy and/or decrease muscle strength and/or abnormal sensation and/or abnormal reflexes;
3. Deficit confirmed by CT, MRI, or X-ray;
4. NDI Score of ≥ 30/100;
5. Unresponsive to non-operative treatment of at least 6 weeks or presence of progressive symptoms or signs of nerve root/spinal cord compression despite continued non-operative treatment;
6. No prior surgical procedures at the operative level and non-prior fusions at any cervical level;
7. Physically and mentally able and willing to comply with the protocol;
8. Signed informed consent;

Exclusion Criteria:

1. Patient does not meet the indication of Anterior Cervical Discectomy and Fusion (ACDF), which is under the surveillance. (Surgical indication of ACDF is approved by National Health Insurance Administration Ministry of Health and Welfare, a blinded third-party authority).
2. More than two vertebral levels required surgery;
3. Immobile levels between C1 and C7 from any cause;
4. Any prior surgery at the operative level or any prior fusion at any cervical level;
5. T-score less than -1.5 (osteoporosis evaluation)
6. Paget's disease, osteomalacia, or any other metabolic bone disease other than osteoporosis;
7. Active infection of surgical site or history of anticipated treatment for systemic infection including HIV
8. Active malignancy: a history of any invasive malignancy (except carcinoma in situ and non-melanoma skin cancer), unless treated with curative intent with no clinical signs or symptoms of malignancy in the past 5 years;
9. Marked instability of the cervical spine on resting lateral or flexion-extension radiographs;
10. Known allergy to device materials including titanium or polyetheretherketone (PEEK);
11. Segmental kyphosis of greater than 11 degrees at treatment or adjacent levels
12. Rheumatoid arthritis, lupus, or other autoimmune disease;
13. Any diseases or conditions that would preclude accurate clinical evaluation;
14. Daily, high-dose oral and/or inhaled steroid or a history of chronic use of high dose steroids;
15. Body Mass Index (BMI) > 35
16. Smoking more than one pack of cigarettes per day;