Comparison of adjacent segment degeneration after anterior cervical decompression and fusion between Zero-profile interbody fusion device and traditional titanium plate fixation and fusion

English Keywords:Anterior cervical discectomy and fusion  Zero-profile interbody fusion device(Zero-P)  Titanium plate  Adjacent segment degeneration

English Abstract:

  【Abstract】 Objectives: To compare the effects after anterior cervical decompression and fusion between Zero-profile interbody fusion device(Zero-P) and traditional titanium plate fixation and fusion for single/double segment spinal cervical spondylosis on adjacent segment degeneration. Methods: This article retrospectively analyzed 113 patients with cervical spondylotic myelopathy from January 2015 to March 2018 who were treated by using Zero-P(group A, n=65; single-segment of group A, n=44; double-segment of group A, n=21) and traditional titanium plate fixation and fusion(group B, n=48; single-segment of group B, n=28; double-segment of group B, n=20). This article compares the operation time and intraoperative bleeding of the two operation methods. Comparison of JOA score and VAS score in 4 groups of patients were carried out before surgery and at final follow-up. The patients were assessed for dysphagia at final follow-up. Lateral cervical X-ray films were used to measure the height of the intervertebral space of adjacent segments at preoperative, postoperative and the final follow-up, and to evaluate the ossification of adjacent vertebrae before and after the follow-up. On the cervical spine MRI, Pfirrmann classification of the intervertebral disc was used to evaluate the degeneration of intervertebral discs in the adjacent segments before surgery and at the final follow-up. Results: The average follow-up time for single-segment group A, single-segment group B, double-segment group A, and double-segment group B groups were 18.0±7.9 months, 15.8±8.8 months, 14.8±6.4 months, and 15.8±8.2 months respectively. The operation time of group A was significantly shorter than that of group B(P＜0.05). There was no significant difference in intraoperative blood loss between the two groups(P＞0.05). The JOA score and VAS score of the four groups of patients were significantly improved at final follow-up compared with those before surgery. No significant difference in JOA improvement rate between the same segment groups(P＞0.05). No significant difference in VAS scores between the same segment groups at final follow-up(P＞0.05). At final follow-up, the height of the upper and lower adjacent intervertebral space of group B was significantly lower than that before and after surgery(P＜0.05). At final follow-up of the other three groups, the height of the upper and lower adjacent intervertebral space was not significantly different than before and after surgery(P＞0.05). At final follow-up, the height of the upper adjacent intervertebral space of the double-segment group B was significantly lower than that in the double-segment group A and the height of the lower adjacent intervertebral space of the double-segment group B was significantly lower than that in the double-segment group A(P＜0.05). There was no significant difference in the height of the upper and lower adjacent intervertebral spaces between single segment group A and single segment group B at final follow-up(P＞0.05). At final follow-up, for the incidence of ossification of adjacent vertebrae, the single-segment group B(32.14%) was higher than the single-segment group A(6.82%) and the double-segment group B(40%) was higher than the double-segment group A(9.52%)(P＜0.05). According to the Pfirrmann classification, the double-segment group B(30%) was more prone to adjacent segmental disc degeneration than the double-segment group A(4.76%)(P<0.05). There was no significant difference in degeneration of intervertebral disc between single-segment group A and single-segment group B at final follow-up(P＞0.05). The double-segment group B(30%) was more prone to adjacent segmental disc degeneration than the single-segment group B(7.14%)(P<0.05). There was no significant difference in degeneration of intervertebral disc between single-segment group A and double-segment group A at final follow-up(P＞0.05). Regardless of single or double segment, group B had a higher incidence of postoperative dysphagia than group A. Conclusions： In the single-segment and double-segment of ACDF, Zero-P and traditional titanium plate fusion can achieve similar clinical effects, but Zero-P has advantage to reduce degeneration of adjacent segment and has more obvious advantage in the comparison of the two segments.