Agreement between surgeons and an independent panel with respect to surgical site fusion after single-level anterior cervical spine surgery: a prospective, multicenter study.

Prospective multicenter cohort study. To assess the: (1) agreement between surgeon and independent review of fusion after single-level anterior cervical decompression and fusion, and (2) influence of surgeon impression of patient status on agreement. Failure to achieve fusion can lead to poor functional outcome. Visual inspection of plain radiographs is used to assess fusion, but this assessment's reliability is not well understood. Of 668 participants in the Cervical Spine Research Society Outcomes Study, 181 underwent single-level procedures. Three independent reviewers and each surgeon assessed fusion (i.e., radiographic trabecular bridging of the graft-vertebral body gap and absence of spinous process motion) on plain radiographs at 3 and 6 months after surgery. Agreement was evaluated with an intraclass correlation coefficient (ICC). The influence of surgeon impression of patient status on agreement was assessed with logistic regression analysis. Agreement was high among reviewers (ICC 0.822 to 0.892) but poor between reviewers and surgeons (ICC 0.308 to 0.484); disagreement was higher when the surgeon reported medical (odds ratio [OR] = 0.19, 95%; confidence interval [CI] 0.12, 0.30; P < 0.001), neurologic (OR = 0.13, 95% CI: 0.09, 0.21, P < 0.001), or functional (OR = 0.19, 95% CI: 0.12, 0.29, P < 0.001) improvement than when the surgeon did not report this improvement. The finding that surgeons and independent reviewers disagreed on fusion assessment highlights the need for objective and reproducible measures of fusion.