Design and implementation of botulinum toxin on cricopharyngeal dysfunction guided by a combination of catheter balloon, ultrasound, and electromyography (BECURE) in patients with stroke: study protocol for a randomized, double-blinded, placebo-controlled trial

Background: Cricopharyngeal dysfunction (CPD) occurs in various neurological disorders, especially stroke. The treatment approaches of CPD include swallowing training, cricopharyngeal dilation, botulinum toxin (BTX) injection, and cricopharyngeal myotomy. BTX injection into the cricopharyngeal muscle is effective and safe for some patients with dysphagia, with a success rate between 43 and 100% (mean = 76%). However, well-designed randomized controlled clinical trials are needed to verify its efficacy and safety for the treatment of CPD. The objective of this study is to explore the efficacy and safety of BTX for neurogenic cricopharyngeal achalasia, when administering an injection into the cricopharyngeal muscle guided by a novel precise positioning method, that combines ultrasound, catheter balloon, and electromyography (BECURE). Methods: BECURE is a single-center randomized, placebo controlled, double-blinded, superiority clinical trial. To detect a significant difference between the 2 groups, a sample size of 44 patients is estimated. The intervention is BTX versus placebo, with 1:1 randomization. The randomization sequence from 1 to 44 was generated using the Statistical Package for Social Sciences. The study is divided into two phases. In the first phase, patients will be injected with BTX or the placebo. In the second phase, patients who received a placebo injection and those who did not respond to the first BTX injection will receive an injection of BTX. The primary outcome is the score of the Functional Oral Intake Scale (FOIS). The secondary outcomes are as follows: upper esophageal sphincter (UES) residual pressure, UES resting pressure, duration of UES relaxation, velopharyngeal and laryngopharyngeal peak pressure, UES opening, pharyngeal construction ratio, residue of bolus in the epiglottis valley or piriform sinus, and penetration and aspiration. Discussion: Dysphagia is a common complication of stroke. There is lack of high-quality evidence for the efficacy of BTX in treating neurogenic CPD. This study will clarify whether BTX injection into the cricopharyngeal muscle can be effective and safe for patients with stroke and CPD.