Natural History of Cricopharyngeus Muscle Dysfunction Symptomatology

Cricopharyngeus muscle dysfunction (CPMD) is a common cause for progressive dysphagia and can lead to dietary restriction, reduced nutrition, weight loss, and pneumonia. There is a continuum between small, non-obstructive cricopharyngeus bars representing mild disease and severely obstructive bars or Zenker's diverticulum forming late-stage disease, but the natural history of untreated CPMD and the associated time course for progression is unknown. Retrospective longitudinal cohort study from a tertiary outpatient dysphagia centre. Patients diagnosed with CPMD by fluoroscopy and either awaiting surgical treatment or electing non-operative management were evaluated through prospectively collected Eating Assessment Tool-10 (EAT-10) and Functional Oral Intake Scale (FOIS). Review of available imaging identified degree of CPMD. We identified 174 patients with CPMD diagnosed between July 1, 2016, and June 30, 2020; 52 patients had serial Eating Assessment Tool (EAT-10) measures obtained at time of diagnosis and follow up appointment without operative treatment. Mean EAT-10 scores increased from 17.1 to 20.6 (3.5 ± 8.1 points, p = 0.002) points. This change was related to those with a Zenker's diverticulum rather than an isolated cricopharyngeus bar. Dietary outcomes measured by FOIS were stable. While some patients showed fluoroscopic progression of bar size, no patients developed a Zenker's diverticulum from a pre-existing bar in this population. Our data indicate patients with a cricopharyngeus bar do not decline in subjective dysphagia score or diet tolerance, however those with a Zenker's diverticulum worsen over time. This has implications for treatment timing and counselling patients but also reflects a need to understand the pathophysiology behind CPMD and the subset of patients who show progression.