Cricopharyngeal Bar on Videofluoroscopy: High Specificity for Inclusion Body Myositis

Objective: To determine the prevalence and characteristics of the cricopharyngeal bar (CPB), defined as marked protrusion with lacking relaxation and stricture of the upper esophageal sphincter on videofluoroscopy, in patients with inclusion body myositis (IBM).

Methods: We conducted a case-control study of comprehensive series of adult healthy individuals and consecutive patients with neuropsychiatric disorders aged over 45 (52 versus 2486). A standard videofluoroscopy was performed.

Results: Overall, 47 individuals with CPB were identified. Of the individuals with CPB, 36% were IBM followed by neurodegenerative disorders, muscular disorders, neuromuscular disorders, and others (32%, 21%, 2.1%, and 8.5%, respectively), indicating the heterogeneity of the etiologies. Against muscular disorders, the sensitivity and specificity of the CPB for IBM were 33% (= 17/52; 95% confidence interval [CI], 20-45%) and 96% (= 264/274; 95% CI, 94-99%), respectively. IBM with CPB showed a higher frequency of obstruction-related dysphagia (88% versus 22%, p < 0.001) and severe CPB (76% versus 23%, p < 0.001) than the control with one. The ratio of the upper esophageal distance at the maximum distension at the level of C6 to that of C4 was lower in IBM with CPB than in the controls with one (0.50 versus 0.77, p < 0.001), which suggests the insufficient opening of the upper esophageal sphincter.

Conclusion: A CPB could be indicative of IBM. The upper esophagus in IBM with CPB became narrow, like a bottleneck. We provide new perspectives of dysphagia diagnosis by videofluoroscopy, especially for IBM-associated dysphagia, to expand the knowledge on the CPB.