Clinical and Radiographic Analysis of Cervical Total Disc Replacement Versus Anterior Cervical fusion using Stand-alone Cage

ABSTRACT

OBJECTIVE: Total intervertebral disc replacement is designed to preserve motion and avoid limitations of fusion after removing local pathology. The authors report the results of a signle-center study to determine functional and radi- ologic outcomes associated with cervical total disc replacement versus those of cervical fusion. METHODS: We retrospectively reviewed the charts and radiographs of patients who underwent a total intervertebral disc replacement(TDR) or a single-level anterior cervical fusion(ACDF) between January 1, 2004, and September 31, 2007. Clinical symptom was assessed using the Visual Analog Scale(VAS) of the neck and of the arm pain. Range of motion was determined by radiologic assessment of flexion-extension radiographs. Data were collected before surgery and at 6 weeks, 3, 6, 12, and 24 months after surgery. RESULT: A total of 125 patients were identified with 63 having TDR(43 males and 20 females) and 62 having fusion(42 males and 20 females). The average age was 49.1 years(TDR) and 51.7 years(ACDF)(p=0.229). The mean neck pain VAS before surgery was 6.52(TDR) and 6.61(ACDF)(p=0.732). At 2-year follow-up, the average neck pain VAS for the TDR group was 1.59 and ACDF 1.85(p=0.168). The mean arm pain VAS before surgery was 6.37(TDR) and 6.60(ACDF)(p=0.335). At 2 years: 1.41(TDR) and 1.65(ACDF)(P = 0.148). More motion(an average of 9.00 degrees at 24 months) was retained after surgery in the TDR group than the fusion group at the treatment level. There was no significant diffe- rence in motion at adjacent levels. CONCLUSION: Total disc replacement maintained physiological segmental motion at the 2-year follow-up. The finding that there was no statistically significant difference between the groups in motion at adjacent levels must be verified on further studies.