Retrograde cricopharyngeal dysfunction and treatment with botulinum toxin: a systematic review.

[PURPOSE] Retrograde cricopharyngeal dysfunction (RCPD) is a disease first described systematically in 2019. The main symptom is inability to belch due to cricopharyngeal muscle dysfunction. Other symptoms include gurgling noises, chest pain, bloating, and excessive flatulence. This paper aims to describe RCPD, the aetiology and diagnosis, treatment options, follow-up, and treatment with botulinum toxin (BT).

[METHODS] A systematic review was done according to the PRISMA guidelines, using the databases PubMed, Embase, and Cochrane at 8/3/2024. The search combined BT with different descriptions of RCPD. All papers were screened by two authors.

[RESULTS] 120 papers were identified in the search. After screening 13 papers describing 472 patients in total were included. Mean age was 29.3 years with 51.1% men. Diagnosis was established in 82.4% of the cases by symptomatology, 2.1% by high-resolution manometry, and 15.3% by oesophagoscopy. The mean amount of BT was 66 units (U). Mean follow-up time was 13 months. After 1-4 weeks 93.7% had an effect post-treatment and 81.0% after 6 months. Common symptoms were inability to belch (99.8%), chest pain and/or bloating (95.4%), gurgling noises (84.9%), and excessive flatulence (75.9%). Common complications were mild and transient dysphagia (59.4%) and reflux (35.4%).

[CONCLUSION] The accumulated numbers of patients with RCPD indicates a growing attention to the plausible condition. Injection with BT is a good and safe treatment of RCPD. Most patients only experience mild and transient complications to the treatment. Much is still unknown about RCPD and conditions for setting the diagnosis needs to be evaluated and established internationally.