Factors Associated With Nonunion After Cervical Fusion Surgery

Abstract

Background Bony fusion is a critical factor in the outcome of cervical spinal fusion surgery. While several factors have been proposed to affect bony fusion, their relative importance remains unclear. This study aimed to investigate the factors associated with bony fusion after cervical spinal fusion surgery. Methods We retrospectively evaluated the significance of the various factors on bone fusion after cervical fusion surgery. Then, multivariate logistic regression analyses were performed to determine the independent factors associated with bony fusion. A receiver operating characteristic (ROC) analysis was performed to evaluate the cutoff threshold. Results This study included a total of 52 patients with a mean age of 64 years. Among them, 28 (54%) were male, and 39 (75.0%) achieved bony fusion. The multivariate logistic regression analysis showed that preoperative intact parathyroid hormone (PTH) levels (odds ratio, 1.04; 95% confidence interval, 1.01-1.08; p-value = 0.02) and hemoglobin A1c (HbA1c) levels (odds ratio, 2.87; 95% confidence interval, 1.07-8.74; p-value = 0.04) were significant factors associated with bony fusion after cervical fusion surgery. The optimum cutoff values of intact PTH and HbA1c were 63.5 pg/mL and 6.2%, respectively. Conclusions This study identified preoperative intact PTH and HbA1c as significant factors associated with bony fusion after cervical fusion surgery. These biomarkers can be used to identify patients at higher risk of nonunion to optimize patient conditions and guide preoperative and postoperative management strategies.

Keywords: anterior cervical decompression and fusion; glycated hemoglobin (hba1c); intact parathyroid hormone; nonunion; posterior cervical decompression and fusion.

Figure 1. Receiver operating characteristic analysis of intact PTH (A) and hemoglobin A1c (B).

The area under the curve, sensitivity, and specificity of intact PTH were 0.66, 0.539, and 0.949, respectively (A). The area under the curve, sensitivity, and specificity of hemoglobin A1c were 0.66, 0.539, and 0.744, respectively (B). PTH: parathyroid hormone