Use of a Zero-Profile Device for Contiguous 2-Level Anterior Cervical Diskectomy and Fusion: Comparison with Cage with Plate Construct

BACKGROUND: A new zero-profile, standalone device (Zero P) was recently developed and has shown a lower incidence rate of complications and competitive clinical outcomes compared with anterior cervical cage with plate construct (CP) in single and multilevel anterior cervical diskectomy and fusion (ACDF). However, there is still concern whether Zero P is appropriate for multilevel ACDF. In addition, there have been few reports of contiguous 2-level ACDF used in conjunction with Zero P. METHODS: We reviewed contiguous 2-level ACDF performed from December 2006 to February 2015. A total of 63 patients met inclusion criteria for the study (CP group =32 cases; Zero P group= 31 cases). All preoperative and postoperative clinical and radiologic parameters were recorded. These parameters were compared between both groups. RESULTS: The postoperative change of Cobb S over time in the Zero P group was significantly different from that in the CP group. The maintenance of Cobb S in the Zero P group was better than that in the CP group (P < 0.05). The maintenance of anterior intervertebral disk height (IDH) at postoperative assessment for the Zero P group was significantly better than that in the CP group (P < 0.05). Within-group comparison of the postoperative change of anterior and posterior IDH over time revealed that theanterior IDH was significantly lower than the posterior IDH in the Zero P group (P < 0.05). CONCLUSION: For 2-level contiguous ACDF, the use of a zero-profile device has the capacity to show compatible outcomes in correction and maintenance of segmental angle if the anterior titanium alloy plate is properly posi-tioned at the anterior vertebral line.