Influence of one-level cervical disc arthroplasty and anterior cervical decompression and fusion on adjacent segment degeneration: a comparative study with two-year follow up

To compare the morbidity of adjacent segment degeneration (ASD) in patients who underwent cervical disc arthroplasty (CDA) and anterior cervical decompression and fusion (ACDF). ACDF used to be considered as the best treatment of cervical degenerative disc disease. It's controversial when ASD was reported as complication after ACDF. CDA was believed to maintain the physiological motion pattern and reduce intervertebral stress. There are few reports comparing the results of two surgeries. Patients undergoing CDA or ACDF from February 2007 to August 2008 got a minimum follow-up of 4 years. The cohort consisted of 150 patients (69 men and 81 women) with an average age of 46.7+/-6.5 years. 45 patients were treated with CDA and 105 patients underwent ACDF. The efficacy was evaluated with the visual analog scale (VAS), the neck disability index (NDI), Japanese Orthopaedic Association (JOA) score and the range of motion (ROM). The anteroposterior and lateral radiographs and over flexion-extension lateral radiographs were obtained. Cervical CT and MRI were obtained if persistent discomforts or new symptoms were claimed. The revised Hilibrand method was adopted to assess the level of ASD. All the 150 patients complete the clinical and radiological follow-up interval (48 months). From investigation, the preservation of motion was notably maintained in the CDA patients. However, there were no statistically significant difference of the ASD incidence based on the VAS, NDI and JOA scores between the two groups. Therefore, the role of CDA in ASD incidence remains unclear unless more randomized controlled trials are conducted and definitive evidence is achieved. CDA significantly increased ROM comparing to ACDF. However, the other scores were not significant different between two groups. More data are needed for solid conclusion.