Influence of surgery on deglutitive upper oesophageal sphincter mechanics in Zenker's diverticulum

BACKGROUND/AIMS: To evaluate the role of upper oesophageal sphincter (UOS) compliance in dysphagia, the functional consequences of surgery were evaluated in eight patients with pharyngeal diverticula. The study examined the hypotheses that hypopharyngeal intrabolus pressure is an indicator of UOS compliance and that UOS opening and intrabolus pressure are normalised by surgery. METHODS: In eight patients and nine healthy controls, we measured the timing of swallow events, UOS relaxation, maximal UOS dimensions, intrabolus pressure, and trans-sphincteric bolus flow rates by simultaneous videoradiography and pharyngeal manometry. RESULTS: Bolus flow rates were not changed by surgery. Surgery significantly increased UOS opening (p = 0.0001) and reduced hypopharyngeal intrabolus pressure (p = 0.0001). The slope of the relation between sphincter area and intrabolus pressure was steeper in patients than controls and was normalised by surgery. Surgery had minor effects on basal UOS tone and timing of swallow events. CONCLUSIONS: Upper oesophageal sphincter compliance is poor in Zenker's diverticulum and is normalised by surgery. Hypopharyngeal intrabolus pressure, which correlates with resistance to trans-sphincteric bolus flow, is a useful indicator of UOS compliance. Intrabolus pressure may be a predictor of outcome after myotomy in pharyngeal dysphagia. Cricopharyngeal myotomy is a mandatory component of surgery for Zenker's diverticulum.