Can Intraoperative Cricopharyngeus Muscle Characteristics Be Used to Predict Treatment Success in RCPD?

Abstract

To investigate intraoperative findings as predictors for favorable outcomes following Botox injection in patients diagnosed with retrograde cricopharyngeus muscle dysfunction (RCPD). A retrospective review was performed on patients who underwent 70-80 U botulinum toxin injection (BT) for treatment of RCPD by a single surgeon between 2018 and 2023. Patient characteristics, intraoperative findings of cricopharyngeus muscle (CPM), symptoms, treatment response, and side effects were identified during preoperative and 1-month postoperative follow-up. A total of 71 patients were included in the study. A majority of the patients were Caucasian (n = 59 [83.1%]), female (n = 37 [52.1%]), with a mean age of 29.2 years (SD = 8.3). Of those, 68% (n = 48) of patients had a complete response to the initial Botox injection at 1-month follow-up. Compared to the mild thickness CPM, the moderate thickness CPM was 7.2 times less likely to have a full response to treatment (odds ratio [OR]: 7.24, confidence interval [CI]: 1.13-46.37, p = 0.037). Similarly, compared to the mild thickness CPM, thick CPM was 38.5 times less likely to have a full response to treatment (OR: 38.5, CI: 4.4-336.5, p = 0.001). Moderate and thick CPMs were less likely to have resolution of symptoms after initial injection with 70-80 U of Botox injection. Further research is needed to establish recommendations regarding dosing for patients with RCPD, especially in those with moderate and thick CPMs.