Comparison of anterior cervical discectomy and fusion with the zero-profile implant and cage-plate implant in treating two-level degenerative cervical spondylosis

Previous studies based on small sample sizes have reported the application of the Zero-P implant (Zero-P, Synthes GmbH, Switzerland) in single anterior cervical discectomy and fusion (ACDF) surgery with excellent outcomes. However, the safety and effectiveness of two-level ACDF with Zero-P implant still remains controversial. A retrospective study was conducted to compare the clinical outcomes and complications between Zero-P implant and conventional cage-plate implant in two-level ACDF for the treatment of degenerative cervical spondylosis. The Japanese Orthopedic Association (JOA) scale score, neck and arm visual analog scale (VAS), bony fusion rates and main complications were recorded. Dysphagia was evaluated according to the Bazaz grading system. A total of 67 consecutive patients in Zero-P group and 72 consecutive patients in Plate group were enrolled in this retrospective study. The total incidence of dysphagia in Zero-P group and Plate group were 40.00% and 55.56% at one week, respectively. Similar improvements were observed in the JOA and VAS pain scores in both groups at the final follow-up (P>0.05). There were no significant difference between two groups concerning other complications such as postoperative hematoma, recurrent laryngeal nerve palsy, cerebrospinal fluid leakage and pseudarthrosis. The Zero-P implant and the traditional titanium plate with cage are both effective treatments for two-level degenerative cervical spondylosis, but the Zero-P implant has a lower dysphagia incidence. Future prospective, randomized and controlled studies with larger sample size are needed.