Paradoxical Stimulatory Response of Remanent Sphincter of Oddi to Buscapina After Endoscopic Sphincterotomy

BACKGROUND/AIMS: Endoscopic removal of bile duct stones has become the treatment of choice, which includes endoscopic sphincterotomy (EST) in the majority of cases, destroying at least partially the Oddi sphincter (OS). Loss of sphincter function in variable grade has been described, but changes in innervation are not known. METHODS: Endoscopic manometry of OS was performed in 14 patients after EST with specialized perfused catheter. Pressure values were registered before and after 10 mg Buscapina injected intravenously. RESULTS: Choledocho-duodenal pressure gradient was absent in all of 14 patients. Basal OS pressure was zero in 7 and conserved in normal range in the remaining 7. Phasic motor activity was registered in 11 patients and was absent in 3 patients. After 10 mg Buscapina intravenous injection, instead of habitual inhibition, increase in basal OS pressure and in frequency of phasic contractions was observed in 9 patients. This response was not related to age of patients, neither with time elapsed between the EST and manometry, nor the estimated size of papillotomy orifice. Duodenal peristalsis was invariably inhibited in all patients. CONCLUSIONS: EST destroys not only the smooth muscle of OS, also alters the innervation interrupting the duodeno-sphincteric nerve circuit. This finding questions the use of Buscapina or other anticholinergic agent as spasmolytic in patients after EST.