Multilevel cervical disc arthroplasty: Long-term outcomes at 3 and 4 levels

Abstract

Background: Multilevel cervical degenerative disc disease in 2 or more segments poses treatment challenges. Anterior cervical discectomy and fusion is a viable treatment option, but one with high rates of adjacent segment disease and pseudoarthrosis. Cervical disc arthroplasty (CDA) is approved by the US Food and Drug Administration for the treatment of 1- and 2-level cervical pathology, with established long-term safety and effectiveness. Limited evidence exists for CDA at more than 2 levels. This study investigates the long-term outcomes of 3- and 4-level CDA out to 7 years. Methods: In a retrospective review of prospectively collected data, patient demographics and surgical characteristics were collected. Patient-reported outcomes (PROs) were collected preoperatively and at 6 weeks, 3 months, 6 months, and 12 months postoperatively, and annually thereafter, including: Neck Disability Index (NDI), numeric rating scales for neck pain and arm pain, the Veterans Rand 12-item Health Survey physical component summary (PCS) score and mental component summary (MCS) score, and patient satisfaction scores. Secondary surgery data were also collected. Predictive methods using mixed-effects regression models were used to analyze the data. Results: Data for 139 CDAs were available for evaluation (n ¼ 116 three-level and n ¼ 23 four-level). Statistical improvement was shown for all PRO scores at all postoperative intervals (P,.001). From preoperatively to 7 years postoperatively, mean NDI decreased from 57.9 to 31.3 (45.9% improvement), mean neck pain decreased from 15.6 to 7.9 (49.4% improvement), mean arm pain decreased from 12.2 to 5.6 (54.1% improvement), mean PCS increased from 29.2 to 41.4 (41.8% improvement), and mean MCS increased from 37.1 to 44.5 (19.9% improvement). Five (3.6%) 3-level patients underwent secondary surgery. Patient satisfaction exceeded 88% 7 years after surgery. Conclusion: Statistical improvement in PROs, with a low rate of secondary surgeries out to 7 years, demonstrates that 3- and 4-level CDA may be performed safely and effectively in appropriately selected patients.