Treatment of megarectum in anorectal malformation with emphasis on preventive aspects: 17 years experience

Megarectum in anorectal malformation (ARM) causes severe morbidity. To compare conservative management (CM) of megarectum with excision (EX), to propose a new classification and to analyse management strategies. Between 2000–2016, we reviewed all ARM to identify megarectum, defined by radiological recto-pelvic ratio > 0.61. A new classification was proposed: primary megarectum (PM) pre-anorectoplasty, and secondary megarectum (SM) post-anorectoplasty, with sub-types. Complications and Krickenbeck bowel function were compared between CM and EX. Of 124 ARM, 22 (18%) developed megarectum; of these, 7 underwent EX. There was no difference in functional outcomes when comparing CM vs EX—voluntary bowel movement (both 86%), soiling (40% vs. 57%) and constipation (both 86%). However, EX was associated with major complications (43%) and the requirement for invasive bowel management, compared to CM (85% vs. 27%, P = 0.02). 6/7 EX needed antegrade continence enema (ACE), one of these has a permanent ileostomy. With strategic changes, incidence of megarectum reduced from 20/77 (26%) to 2/47 (4%) after 2013 (P = 0.002). EX did not confer benefit in the functional outcome but carried a high risk of complications, often needing ACE or stoma. By adhering to strategies discussed, we reduced the incidence of megarectum and have avoided EX since 2013.