Risk factors and prognosis analysis of dysphagia after occipitocervical fusion surgery: a retrospective study of 43 cases

Objectives: To analyze the risk factors for developing dysphagia after occipitocervical fusion (OCF) and investigate possible mechanisms and prognosis.

Methods: The case data of 43 patients who underwent OCF were retrospectively reviewed. Patients were divided into group A (dysphagia group) and group B (non-dysphagia group) based on Bazaz scoring criteria. Baseline data and imaging parameters were collected: O-C2 angle, C2-7 angle, pharyngeal inlet angle (PIA), posterior occipital cervical angle (POCA), O-EA angle, Oc-Ax angle, Atlas-dens interval, C2-7 sagittal vertical axis (SVA), T1 slope, narrowest oropharyngeal airway space (nPAS), and thickness of the prevertebral soft tissue. Potential risk factors were identified via one-way intergroup comparisons and included in multivariable logistic regression analysis. Pearson or Spearman correlation analysis was performed to assess associations between dnPAS% and each parameter and inter-parameter correlations. Predictors were selected to plot receiver operating characteristic (ROC) curves for diagnostic evaluation. Prognosis was analyzed using the Kaplan-Meier method and curvilinear regression.

Results: Dysphagia occurred in 17 of 43 patients (39.53%). By the final follow-up (≥ 12 months), 11 patients (25.58%) had residual symptoms. Baseline factors, including dyspnea (P = 0.028), operative segment (P = 0.021), operative time (P = 0.006), anesthesia time (P = 0.025), solitude (P = 0.019), and satisfaction (P < 0.001), differed significantly between groups. Imaging parameters dO-C2a (P < 0.001), dPOCA (P < 0.001), PoPIA (P = 0.036), dPIA (P < 0.001), dOc-Axa (P = 0.001), dC2-7 SVA (P = 0.040), PonPAS (P = 0.004), dnPAS (P = 0.005), and dnPAS% (P < 0.001) were also significantly different. Multivariable regression analysis identified dPIA (OR = 0.870, P = 0.008) as an independent protective factor. ROC analysis showed dPIA had good diagnostic value (AUC = 0.855) with a cutoff of -8°. Prognostic analysis indicated rapid recovery was possible by 3 months postoperatively, with full recovery achieved in ~ 30% of patients by 1 year, after which recovery plateaued.

Conclusion: Postoperative dysphagia after OCF appears to result from multiple factors involving both "static + dynamic" elements. dPIA is a reliable predictor, with patients having a dPIA >-8° being less likely to develop dysphagia. However, only ~ 30% of patients achieve full recovery.