Topical nitric oxide treatment after pull through operations for Hirschsprung disease

The diagnosis and treatment of Hirschsprung disease are well standardized. Symptoms of obstruction after surgery for Hirschsprung disease may result from residual spasticity of the internal anal sphincter. Nitric oxide (NO) is the chemical messenger mediating relaxation of the internal anal sphincter and its exogenous application results in a relaxation response in smooth muscle. The purpose of this study was to investigate topical NO application for obstructive symptoms after surgery for Hirschsprung disease and to correlate the symptoms with manometric findings with a view to directing further management.

The authors reviewed application of topical NO on six symptomatic children who were operated for Hirschsprung disease. Eighteen patients older than 3 years of age were evaluated for anorectal manometric, functional and clinical outcome. The symptoms included enterocolitis in three patients and constipation in three patients. NO ointment was applied twice daily for 6 weeks in symptomatic patients and manometry was repeated.

Anorectal manometric evaluation of six patients showed high internal anal sphincter tone without reflex relaxation on applying distending pressure to the rectum. Marked improvement of symptoms was noted after 6-week application of topical NO and maximal internal anal resting pressure decreased significantly (35% reduction). After ceasing application of topical ointment, increased maximal anal resting pressure was seen again.

Although anal sphincter hypertonicity is not thought to be the only cause of post-operative obstructive symptoms, relaxation of the internal anal sphincter may improve the symptoms. Topical NO can be used for treatment of obstructive symptoms in Hirschsprung disease. We managed our symptomatic patients successfully with local NO application with a reversible chemical sphincterotomy. NO could be used as a therapeutic modality.