Is the anorectal sphincter damaged during a transanal endorectal pull-through (TERPT) for Hirschsprung's disease? A 3-dimensional, vector manometric investigation.

BACKGROUND/
PURPOSE: The transanal endorectal pull-through technique (TERPT) for Hirschsprung's disease (HD) exercises considerable traction on the anorectal tissue during dissection. So the question arises as to whether TERPT impairs the integrity of the anorectal sphincter. Computerised 8-channel vector manometry allows a segmental, 360 degrees analysis of muscular defects along the anal canal. Such data after TERPT are not available yet.
METHODS: Between 2002 and 2004, 7 children underwent primary TERPT for HD of the rectosigmoid. All could be recruited for follow-up examinations. Stooling pattern, rectal examination, conventional 4-channel and computerised 8-channel vector manometry were assessed; the anal sphincter pressure at rest (ASPR), rectoanal inhibitory reflex (RIR), anal canal length (ACL), high pressure zone (HPZ), maximal segmental pressure (max SP), segmental/total asymmetric index (SAI/TAI), vector volume at rest (VV) were studied. Mean pre- and postoperative values were compared (pre/post).
RESULTS: After a mean of 14 months (range 3-21 months) all children had spontaneous bowel movements, with no complaints of encopresis or constipation. 4-channel manometry revealed an unchanged ASPR (48.1/49.2 mmHg). RIR was present in 1/7. Computerised 8-channel comparison revealed no changes for ACL (15.4/16 mm), HPZ (60/53.19 % of ACL), SAI (17.6/18.63 %) and TAI (35.8/35.63 %). A postoperative increase was noted for max SP squeeze (141.4/178.7 mmHg) and VV (38 161/46 680 mmHg/cm (2)). In conclusion, the TERPT for HD preserves the functional integrity of the anorectal sphincter complex and has a favourable clinical and manometric outcome.