Outcome Evaluation of Zero-Profile Implant Compared with an Anterior Plate and Cage Used in Anterior Cervical Discectomy and Fusion: A Two-Year Follow-Up Study.

AIM To compare the clinical outcome and complications between Zero-P implant and cage with anterior plate in patients undergoing anterior cervical discectomy and fusion (ACDF). MATERIAL AND METHODS 50 patients underwent ACDF operation of which 23 patients had Zero-P implanted and 27 had cage and plate implanted. Preoperative and Post-operative clinical evaluation included Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI) score and Short form 36 (SF-36). Incidences of dysphagia-related symptoms were recorded. Plain radiographs were performed 2 days postoperatively and at follow-up to evaluate cervical prevertebral soft tissue, sagittal alignment, fusion rate and implant failure. RESULTS In both groups, the JOA and SF-36 scores significantly increased, cervical sagittal alignment significantly corrected and the NDI score dropped compared to the preoperative at follow-up. All patients achieved solid fusion and no implant displacement was observed. The thickness of the prevertebral soft tissue at 2 days and 3 months postoperatively was lower in the Zero-P group. The incidence of dysphagia in the Zero-P group was significantly lower and the duration was much shorter. CONCLUSION Zero-P used in ACDF could lead to similar clinical and radiographical outcomes compared with cage and plate, but with lower incidence and shorter duration of dysphagia.