Rectal mucosal dissection during transanal pull-through for Hirschsprung disease: the anorectal or the dentate line?

Purpose: Both the dentate line (DL) and anorectal line (ARL) are anatomic landmarks for rectal mucosal dissection during transanal pull-through for Hirschsprung disease. We compared outcome after rectal mucosal dissection commencing above the DL (DL group; n = 8) with outcome after rectal mucosal dissection commencing on the ARL (ARL group; n = 6) with normal babies (Cont group; n = 10).

Methods: Rectal mucosal dissection commenced on the ARL in the ARL group and at various levels (0-10 mm) above the DL in the DL group. Outcome was assessed prospectively for 6 months using a standard structured questionnaire.

Results: Subject demographics were not significantly different. Differences in frequency of motions between the ARL and Cont groups were not statistically significant after 3 months of age, but the DL group had significantly more motions than the other 2 groups after 4 months of age (P < .01). At 6 months of age, fecal staining was 17% in the ARL group, 63% in the DL group, and 0% in the Cont group. Anal shape was normal in the ARL and Cont groups, but 50% of the DL group had visible anal mucosa.

Conclusion: Bowel function in the ARL group is similar to normal, and because the ARL is easily identifiable without the need for subjective interpretation, we recommend using the ARL as a landmark for rectal mucosal dissection during transanal pull-through for Hirschsprung disease.