Sa1600 Colonoscopy As a New Tool in Determining the Transition Zone in Endoanal Pull-Through in Hirschsprung's Disease - Preliminary Results

Abstract

Colonoscopy As a New Tool in Determining the Transition Zone in Endoanal Pull-Through in Hirschsprung’s Disease Preliminary Results Erika P. Ortolan, Pedro L. Lourencao, Gisele O. Orsi, Bonifacio K. Takegawa Surgery, Botucatu Medical School UNESP Univ Estadual Paulista, Botucatu, Brazil Background: Surgical treatment of Hirschsprung’s disease (HD) has changed in recent decades, with attempts to reduce extensive surgical dissections. Independent of the technique used, the surgery consists in colectomy of the aganglionic region, beyond the transition zone. Since De la Torre & Ortega first described the exclusive transanal endorectal pull-through (TEPT) technique in 1998, it has become the technique of choice, especially in short aganglionic segments. However, recognizing the transition zone during TEPT is very difficult, leading to a procedure involving several frozen section biopsies and that requires an experienced pathologist. Kohno et al (2005) described the use of colonoscopy in determining a landmark for the location of pull-through with relatively accuracy, denominated the “shorebreak” finding, based on the principle that while normal bowel exhibits peristaltic movements, aganglionic bowel does not. He developed a retrospective study comparing the shorebreak finding in colonoscopy marked with India ink with pathological findings in frozen section biopsies. Based on this single report, our group decided to test this new approach, in a prospective study. The purpose of this work was to report our preliminary results concerning the prospective use of colonoscopy as a new tool to determine the transition zone in HD. Patients and Methods: Colonoscopy was prospectively performed on four patients with HD diagnosis, previously confirmed by anorectal manometry, contrast enema and suction biopsies. The exam was performed just prior to TEPT, using the same anesthetic and bowel prep procedure. The area marked with India ink was chosen following observation of colon motility during colonoscopy, in which the absence of motility identified the beginning of the aganglionic area. For endoscopic tattooing, physiological saline was injected locally submucosally to raise the mucosa, followed by the injection of India ink. All the exams were performed by the same pediatric surgery team member (main author), who was unaware of the contrast enema results. Informed consent to perform the exam was obtained. Results: In all patients, the shorebreak finding marked with India ink was equivalent to the aganglionic segment length and transition zone in contrast enemas. The patients were submitted to TEPT beyond this marked area. The excised colon was opened and the transition zone was macroscopically equivalent to the marked area. These results were confirmed by anatomopathological findings using HE, acetylcholinesterase and calretinin stains. Conclusion: Given these preliminary results, it is our conclusion that endoscopic marking of the shorebreak finding provides an important new tool for determining the point of TEPT in the treatment of HD, especially in hospitals that cannot depend on intraoperative frozen sections or experienced pathologists.