(A149) The Effects of Occipito-Cervico-Thoracic Fusion on Postoperative Dysphagia Severity in Adult Patients

Introduction: Occipito-cervical (OC) and occipito-cervico-thoracic (OCT) fusions are known to cause postoperative dysphagia. Various parameters and measurements have been posited as mechanisms behind the cause of postoperative dysphagia. We investigated the degree to which deviation from neutral O-C2 angle, pharyngeal inlet angle (PIA), pharyngeal anterior-posterior space (PAS) diameter, and vertebral levels fused would have on subjective reports of dysphagia and objective reports of the severity of swallowing dysfunction in adults who have undergone OC/OCT1 fusion.

Methods: A retrospective chart review was completed from 2000 to 2022 on adult patients who had undergone posterior occipito-cervical fusion with reported postoperative dysphagia without any preoperative subjective swallow concerns. Data was collected on vertebral level fused, O-C2 angle, PIA, and PAS diameter; dysphagia severity was recorded from postoperative Modified Barium Swallow Studies. Statistical analyses were performed in R.

Results: Twenty-five patients were included in the study. Mean change between pre and post O-C2 angle, PAS diameter and PIA were -0.15°, -0.60mm, and 0.22° respectively. When compared to fusion levels O-C2 (n=13), patients with fusion levels O-C3 or greater (n=12) had progressively higher severity of dysphagia (p < 0.001). An increase in the PIA was associated with increasing severity of swallow dysfunction (coefficient=0.22, p=0.0038). PAS diameter, OC2 angle and age were not significantly associated with severity of swallow dysfunction.

Conclusions: The notable incidence of postoperative dysphagia following OC/OCT1 fusions warrants close monitoring and routine assessment. PIA can potentially be used to predict dysphagia occurrence and severity, and thus serve as a quality improvement metric, which may be useful in preoperative planning and prevention of postoperative dysphagia.