The effects of the posterior sagittal approach on rectal function (experimental study).

The posterior sagittal transsphincteric approach has been used for the treatment of anorectal malformations in children and for other acquired conditions mainly in adults. Although the reports on clinical results indicate that the division of the sphincteric mechanism does not harm the function of the voluntary muscles, there are no experimental objective evaluations of the rectal function and fecal continence after a posterior sagittal transsphincteric approach. Sixteen dogs were studied forming four groups of four animals each. Group I was subjected to a posterior sagittal approach only without opening of the rectum. Group II underwent a posterior sagittal approach plus posterior and anterior rectotomy. Group III underwent a posterior sagittal approach plus a perirectal dissection, and group IV underwent only a perirectal dissection without posterior sagittal incision. All animals were evaluated clinically and manometrically preoperatively and postoperatively and were followed up to 12 weeks. Results indicated that the perirectal dissection with and without posterior sagittal incision provoked the most severe changes in bowel control and manometric parameters. Posterior sagittal approach with or without rectotomy provoked minimal or no changes in bowel function and rectal manometry. This experimental study supports the clinical experiences and indicates that the posterior approach does not interfere with the function of the sphincteric mechanism.