Comparison of the mid-term follow-up results between Bryan cervical artificial disc replacement and anterior cervical decompression and fusion for cervical degenerative disc disease

Abstract

Objective To evaluate the mid-term tollow-up results of cervical artificial disc replacement (CADR) for cervical degenerative disc disease,and to explore whether it can reduce the occurrence of adjacent segment degeneration (ASD).Methods A prospective comparative study of 93 patients who underwent CADR or anterior cervical decompression and fusion (ACDF) for cervical degenerative disc disease were conducted.All patients were followed up for more than 6 years.The Japanese Orthopaedic Association (JOA) score,neck disability index (NDI),Odom's scale,X-rays and magnetic resonance imaging (MRI) were used to evaluate the clinical and radiologic results.Results Twenty eight patients who underwent CADR and 35 patients who underwent ACDF had complete follow-up data.At final follow-up,the JOA score and NDI improved significantly in both groups.Between the two groups,there was no significant difference in terms of JOA score,NDI and Odom's scale.The sagittal alignment was well maintained in both groups.The total cervical spine range of motion (ROM) had no significant change for the CADR group,whereas,it significantly decreased for the ACDF group.The ROM at the replacement level of CADR patients decreased from 9.5° ± 3.7° before operation to 7.0° ± 3.0° 3 months after operation,and it was maintained to 6.6° ± 4.1° at final follow-up without significant decrease.Lateral radiographs and T2-weighted MRI showed the incidence of ASD in CADR group was significantly lower than that in ACDF group.Conclusion The six-year follow-up results of CADR are basically satisfactory.Compared with ACDF,it could better preserve physiological motion and biomechanics of cervical spine,and reduce the incidence of ASD. Key words: Cervical vertebrae; Intervertebral disk; Prosthesis implantation; Spinal fusion; Follow-up studies