Functional outcome after Swenson's operation for Hirshsprung's disease

Hirschsprung's disease (HD) is one of the most common causes resulting in lower intestinal obstruction in children with atypical clinical symptoms and inconspicuous morphological findings by barium enema X-ray. Recently, this situation has been largely ameliorated by improvement of instrument for measurement of anorectal pressure. By now, anorectal manometry has been regarded as a routine means for functional assessment and diagnosis of HD. It is accurate in nearly all cases of HD with characteristic absence of rectoanal inhibitory reflex. Different surgical modalities of treatment are available and Swenson's operation is one of the surgical procedures done for HD. Anorectal manometric findings may change after Swenson's operation with improvement of rectoanal inhibitory reflex in some cases. We aimed to evaluate functional results after Swenson's operation for HD using anorectal manometry.

Between 1996 and 2005, 52 patients were diagnosed with HD and operated upon by Swenson's operation in Gastroenterology Center, Mansoura University. There were 33 males (63.46%) and 19 females (36.54%) with a mean age of 3.29 +/- 1.6, (range 2-17 years). Anorectal manometry and rectal muscle biopsy were done preoperatively for diagnosis but after operation anorectal manometry was done after every six months and then yearly.

All of the 52 patients showed absent rectoanal inhibitory reflex on manometric study with relatively higher resting anal canal pressure and within normal squeeze pressure. Postoperatively, there were 35 continent patients (67.31%) with 11 patients (21.15%) showing minor incontinence and six (11.54%) with major incontinence. On the other side, there were five patients (9.62%) with persistent constipation after operation (three due to anal stricture and two due to residual aganglionosis). Postoperative manometric study showed some improvement in anal sensation with the rectoanal inhibitory reflex becoming intact in six patients (11.54%) four years after operation.

Anorectal manometry is a more reliable method for diagnosis of HD than barium enema X-ray but for final diagnosis, it is reasonable to combine anorectal manometry with tissue biopsy. Functional outcome after Swenson's operation for HD may improve in some patients complaining of incontinence or constipation. Anorectal manometry may show improvement of the parameters after Swenson's operation.