Endosonographic study of anal sphincters in patients after surgery for Hirschsprung's disease

Abstract Purpose: This study was performed to evaluate the relationship between endosonographic findings of anal sphincters and anorectal function in patients after surgery for Hirschsprung's disease. In addition, whether internal sphincterotomy or sphincterectomy was accomplished was examined in each procedure by anal endosonography. Methods: Fifteen patients, aged 11 to 20 years, were examined. Nine patients underwent modified Duhamel's operation, three underwent Rehbein's operation with anorectal myectomy, and three underwent modified Martin's operation. All 15 patients were examined by anal endosonography using a sonographic scanner (Aloka SSD 2000) with a 7.5-MHz radial rotating endoprobe, clinical bowel assessment, and manometric study. Results: After the modified Duhamel operation, anal endosonography showed an interruption of the external anal sphincter (EAS) in eight of the nine patients, as a high, mixed, or low echoic lesion in the hyperechoic band correlated to the EAS. The locations of the interruption were wide in patients with mild constipation. An interruption of the internal anal sphincter (IAS) was observed in all nine patients, as a hyperechoic lesion in the hypoechoic band correlated to IAS, which indicated internal sphincterotomy. After Rehbein's operation with anorectal myectomy, an interruption of EAS was observed in all three patients as a high or low echoic lesion in the hyperechoic band. An interruption of IAS was observed in all three patients. After the modified Martin's operation, an interruption of EAS was observed in two of the three patients as a high or low echoic lesion in the hyperechoic band. An interruption of IAS was observed in all three patients. Conclusion: Anal endosonography showed detailed distributions of EAS and IAS in patients after surgery for Hirschsprung's disease and complete internal sphincterotomy or sphincterectomy after these operations.