Abstract
Introduction
Anterior cervical discectomy and fusion's (ACDF) reported pseudarthrosis rate rises up to 20% for single-level and 50% for multi-level procedures. Interspinous motion based on functional cervical spine X-rays analysis has been proposed as tool for assessing spine fusion. Previous studies comparing this assessment with direct intra operative visualization during ACDF revision surgery in patients treated with an anterior plate report that an interspinous motion of less than 1 mm correlates with complete fusion. To our knowledge, there is no literature regarding this assessment in patients undergoing an ACDF using zero profile implants. The purpose of this study is to compare interspinous motion in patients treated with an ACDF using zero profile implants to those operated with an anterior plate, after complete spinal fusion confirmation with a computed tomography (CT).
Material and Methods
Cross-sectional study of 22 patients with a CT-confirmed spinal fusion after ACDF. Twelve patients (16 levels) were treated with an anterior plate, while a zero profile implant was used in the remaining ten patients (17 levels). Interspinous motion at the instrumented levels was evaluated in functional cervical spine X-rays for both groups, stratified by fused level (Student's t-test, ANOVA, Stata 12). Motion values were obtained independently by a radiologist and an orthopedic surgeon, following Song's guidelines (Song et al. J Bone Joint Surg Am 2014;96:557–63).
Results
Patients treated with an anterior plate had an interspinous motion of less than 1 mm, while those patients in which a zero profile implant was used presented a statistically significant greater motion at the fused level (p = 0.0082). The instrumented level did not affect interspinous motion (p > 0.05).
Conclusion
Patients treated with an anterior plate had an interspinous motion of less than 1 mm, while those patients in which a zero profile implant was used presented a statistically significant greater motion at the fused level (p = 0.0082). The instrumented level did not affect interspinous motion (p > 0.05).