['The development of a cricopharyngeal dysfunction is associated with a hypertonic cricopharyngeus (CP) muscle. Therefore, CP myotomy has been advocated by some authors to be an essential part of repair of this condition. However, little objective data exists to show that there is improvement in the upper esophageal sphincter (UES) after CP myotomy. This study assesses the impact of CP myotomy on UES opening.', 'Prospective.', "Twenty patients treated at a university tertiary care center for cricopharyngeal dysfunction between 1998 and 2003 were identified. All patients underwent CP myotomy with or without Zenker's diverticulectomy. These patients had videofluoroscopic swallow studies before and after repair. The values of UES opening for 3 mL boluses from pre- and postrepair studies were compared with each other as well as with normal controls. Sixty percent (12/20) of the patients had a Zenker's diverticulum. Of these 12 patients, 5 had undergone previous attempts at surgical correction. Cricopharyngeal myotomy by way of an external approach, with or without Zenker's diverticulectomy, was performed in all patients by the senior author.", "Before Zenker's diverticulectomy and CP myotomy, the mean UES opening (n = 20) for a 3 mL bolus was 0.30 cm +/- 0.17, which was 57% of the mean of 60 normal controls (0.52 cm +/- 0.15) (P < .001). After repair, the mean UES opening for the same bolus size improved to 0.51 cm +/- 0.16 (P < .0001). The UES opening size in patients who have undergone repair is comparable with that of the normal controls (P > .05)."] Does cricopharyngeal myotomy normalize the opening size of the upper esophageal sphincter in cricopharyngeal dysfunction?