Hirschsprung's disease: Problems with transition-zone pull-through

Background/Purpose: It is generally accepted that if surgery for Hirschspru ng's disease is to be successful, ganglionic bowel must be anastomosed to t he lower rectum or anal canal. Above the aganglionic distal bower lies a tr ansition zone (TZ) where more subtle abnormalities of innervation are appar ent. The significance of this transition zone in respect to the functional outcome of surgery has received little attention. The aim of this study was to identify the incidence of transition zone pull-through (TZPT) in a coho rt of children who underwent surgery for Hirschsprung's disease, to identif y the reasons why TZPTs occurred, and to identify the functional consequenc es. The authors report the long-term outcome of these children with emphasi s on bowel function and the results of subsequent surgery. Methods: A Retrospective study was conducted of children treated at a singl e institution from 1979 through 1994. TZPT patients were subject to detaile d review of surgical records and histopathologic material. Results: Thirteen children were identified with a TZPT. In 12 cases, histop athologic errors contributed to the TZPT: in 5 cases this was caused by sin gle point biopsies missing an asymmetrical TZ, whereas in 7 cases the histo pathologic features of the TZ were not recognized. In 1 case the TZPT was c aused by surgical error. As a consequence of the TZPT 7 children underwent repeat pull-through. One child is fully continent, one has daytime fecal co ntinence, and 2 others are incontinent. Two children have permanent stomas. One child is clean with antegrade colonic washouts. Repeat pull-throughs w ere not attempted in 6 children. Two children have achieved full continence , 2 have permanent stomas, 1 is clean with antegrade colonic washouts, and 1 child receives regular suppositories. Conclusions: Transition zone pull-throughs occurred because of a combinatio n of surgical and histopathologic errors. The transition zone may follow an asymmetric course around the circumference of the bower and may be missed if single-point extramucosal biopsy specimens are taken. Recognition of the subtle histologic features of the transition zone requires an experienced pathologist. The functional consequences of a TZPT are severe, with symptom s of constipation, diarrhea, and incontinence. The results of revisional pu ll-through were disappointing. Serious consideration should be given to alt ernative procedures such as the antegrade continence enema operation. J Ped iatr Surg 35:1805-1809. Copyright (C) 2000 by W.B. Saunders Company.