Gastroesophageal Reflux After Combined Lower Esophageal Sphincter and Diaphragmatic Crural Sling Inactivation in the Rat

Abstract

This study tests the hypothesis that eitherselective or combined destruction of the loweresophageal sphincter and the diaphragmatic crural slingshould induce reflux in the rat. Pull-through perfusion manometry was performed before and after loweresophageal myectomy, crural myotomy, or both. pHmonitoring was used to detect reflux. Unmanipulated ratsserved as controls. Paired t tests were used for comparison of pre- and postoperative pressurevalues and contingency tables with Fisher's tests forexamining the association between the interventions andthe appearance of reflux. Esophageal myectomy decreased only sphincteric pressure from 25.9± 15.5 to 9 ± 6 mm Hg (P < 0.01),whereas crural myotomy decreased only sling pressurefrom 26.2 ± 13.3 to 7.3 ± 3.9 mm Hg (P< 0.01). Simultaneous performance of both procedures decreasedsphincteric and crural pressures from 20.4 ± 7.5to 7.6 ± 4.3 mm Hg (P < 0.01) and from 45.9± 20.6 to 18.2 ± 7.4 mm Hg (P < 0.01),respectively. None of the control, myectomy, or myotomy animalsshowed reflux upon pH-metry but 5/8 rats in which bothprocedures were performed had prolonged acid exposure.No esophagitis was seen. In conclusion, normal rats do not have reflux. Selective destructionof either the sphincter or the crural sling does notinduce reflux, despite causing flattening of theirrespective manometric profiles. Conversely, combined inactivation of both components issignificantly associated with reflux.