# Retrograde Cricopharyngeal Dysfunction: An Update of Pathophysiological Mechanisms and Future Directions

## TL;DR

This review summarizes the causes and mechanisms of retrograde cricopharyngeal dysfunction, highlighting gaps in understanding and the need for future research.

## Contribution

The paper provides an updated overview of R-CPD mechanisms and identifies areas for future investigation.

## Key findings

- Family history and childhood onset are common in R-CPD patients.
- Gastroesophageal and laryngopharyngeal reflux are prevalent in R-CPD.
- Botulinum toxin provides long-term symptom relief, suggesting neuroplastic adaptation.

## Abstract

This scoping review aimed to summarize the current literature on the etiological and pathophysiological mechanisms associated with the development of retrograde cricopharyngeus dysfunction (R-CPD) through a PRISMA literature search. According to the current literature, a family history of R-CPD was reported in 28.0% of patients across studies, with childhood onset in 55.5% of cases. Gastroesophageal reflux disease and laryngopharyngeal reflux disease prevalence in R-CPD patients ranged from 16.3 to 51.9%, with improvement of heartburn symptoms after treatment. High-resolution manometry revealed dysmotility disorders in 43.5–80.0% of patients, with absent peristalsis in 11–25%. Carbonated drink provocative testing provided diagnostic usefulness in patients with unclear diagnoses by demonstrating failure of cricopharyngeal sphincter relaxation for retrograde gas. Notably, 75.5–79.9% of patients maintained symptom relief beyond the expected pharmacologic duration of botulinum toxin (approximately 6 months), suggesting potential neuroplastic adaptation or learned compensatory mechanisms in overcoming retrograde cricopharyngeal sphincter dysfunction. The pathophysiology of R-CPD remains incompletely understood, with a lack of epidemiological and pediatric studies. The genetic and environmental factors may play a key role, but future studies are needed to clarify their roles in the development of R-CPD.