Introduction: Swallowing sounds can be heard in the lower esophagus by xiphoid auscultation. We hypothesize that the xiphoid sound analysis could provide information concerning the integrity of the esophagogastric junction (EGJ), i.e., superposition of the lower esophageal sphincter (LES) and the diaphragm to assess clinical diagnosis of gastroesophageal reflux disease (GERD) and results of Nissen fundoplication (NF). The aim was to evaluate the changes in sound parameters using our acoustic technique after reorganization of the EGJ after NF.
Methods: For 21 patients with GERD and hiatus hernia, two microphones were placed below the cricoid and on the xiphoid cartilages. The frequency and duration of xiphoid sounds, esophageal transit time were calculated. We defined the xiphoid sound as composed of vibration groups separated by periods >100 ms. The number of vibration groups, number of vibrations per group, and interval between groups were also calculated.
Results: The xiphoid sound frequency was increased after NF, and the esophageal transit time and xiphoid sound duration were significantly decreased. A significant correlation was found between xiphoid sound duration and LES-diaphragm displacement. The number of vibration groups and interval between groups were reduced after NF.
Conclusion: The acoustic technique for swallowing revealed the effects of NF upon the dynamic profile of the EGJ. The organization of vibration groups at the EGJ suggested that the passage of the bolus was modified by hiatus hernia, i.e., dissociation between the LES and the diaphragm and regularized by NF. Concomitant acoustic and radiologic study should contribute to better understanding of sound related to EGJ structure and boli.