PRELIMINARY EXPERIENCE WITH INTRASPHINCTERIC BOTULINUM TOXIN FOR PERSISTENT CONSTIPATION AFTER PULL-THROUGH FOR HIRSCHSPRUNGS-DISEASE

Although most children who have Hirschsprung's disease have an excelle nt result after pull-through surgery, some experience persistent const ipation caused by ''internal sphincter achalasia.'' Anal myectomy has been advocated for this problem, but it results in permanent injury to the sphincter and is not universally effective. Botulinum toxin has b een safely used to selectively and reversibly weaken a variety of volu ntary muscles and sphincters in both adults and children. Injection of botulinum toxin into the internal anal sphincter (IAS) should theoret ically produce the same functional result as anal myectomy without per manent sphincter injury. Four children aged 4 to 8 years presented wit h persistent constipation after a pull-through procedure for Hirschspr ung's disease. Two had associated encopresis, both of whom had previou s myectomies. The authors performed four-quadrant intrasphincteric bot ulinum toxin injection (total dose, 15 U). Resting IAS pressure decrea sed in all children 4 to 8 weeks after injection. Patients have been f ollowed up for 7 to 9 months. One child (with Down's syndrome) remaine d symptomatically unchanged. The other three families reported signifi cant improvement in bowel function in their children. In two of these, there was a return of symptoms 6 months after injection; one child un derwent reinjection with good results. Postinjection incontinence occu rred in three children, but resolved after several weeks in the one wh o did not have encopresis before botulinum toxin injection. These prel iminary results suggest that botulinum toxin may represent a less inva sive alternative to anal myectomy for children who have severe constip ation after surgery for Hirschsprung's disease. If myectomy is contemp lated, botulinum toxin may be useful as a means of predicting which ch ildren may benefit.