How best to expose the entire surgical anal canal in the operative field during transanal pull-through for Hirschsprung's disease: a crucial step that determines success.

PURPOSE: During transanal pull-through (TAPT) for Hirschsprung's disease (HD), exposing the entire surgical anal canal (SAC) including the squamo-columnar junction, or anorectal line (ARL) is a crucial step for minimizing problematic postoperative bowel function. We present a hint for exposing the entire SAC.

METHOD: Histologically, the ARL represents the junction of proximal unilayer columnar colorectal mucosa with distal stratified squamous epithelium and is the proximal limit of the SAC. It is an obvious landmark; proximal mucosa is vivid pink and distal mucosa is more whitish. We use the Lone Star (LS) self-retaining retractor system to expose the ARL. Before we attach the LS hooks to the anal sinuses on the dentate line full-circle, we place 3/0 sutures at 0, 3, 6, and 9 o'clock around the anus to expose the anal sinuses. If the patient's buttocks cannot be positioned as described or the patient is too high on the table, the LS ring does not sit well, resulting only in dilatation and lengthening of the SAC without prolapse. By hanging the patient's buttocks 5 cm over the end of the table, the LS ring sits snugly and the ARL and entire SAC prolapse to the anal verge.

RESULTS: Good positioning, as described, greatly facilitated dissection in 61/68 TAPT cases, while poor exposure hindered treatment in 7/68.

CONCLUSION: Thorough exposure of the entire SAC, which is crucial for adequate TAPT, is greatly facilitated by patient positioning.