Colorectal / ARM & Hirschsprung

Colorectal and anorectal malformations (ARM) encompass a spectrum from Hirschsprung disease to cloacal anomalies. Hirschsprung disease is defined by absent ganglion cells and hypertrophic nerves; diagnosis requires suction rectal biopsy at least 1 cm above the dentate line, with both findings necessary to avoid false positives [e933-c4,e933-c5]. Irrigation with large-bore tubes (20F Foley, 10–20 cc aliquots) is the mainstay of acute management [e933-c1,e933-c2]. Transanal Swenson pull-through is preferred for standard rectosigmoid disease, leaving <1 cm aganglionic tissue above the dentate line, which ganglionic bowel can overcome [e933-c13,e933-c20]. Transition-zone pull-throughs (nerves >40 microns) require revision . Anorectal malformations are stratified by fistula type, sacral ratio, and spine quality, which together predict continence potential [e951-c34,e951-c35,e951-c36]. Perineal and vestibular fistulas with normal sacrum have 95–100% continence rates [e937-c20,e937-c21]; bladder-neck fistulas with sacral agenesis have ~20% . Colostomy should be descending/sigmoid, fully diverted, to avoid acidosis and UTI [e951-c14,e951-c16]. Cloaca (single perineal opening, no anus) is managed by hydrocolpos drainage at colostomy, endoscopy at 2–3 months, and repair by 6–12 months . Common-channel length and urethral length (from takeoff to bladder neck) determine operative approach: urogenital mobilization if channel ≤3 cm and urethra ≥1.5 cm; otherwise preserve the channel as urethra and separate the vagina [e957-c20,e957-c21]. Native vagina is preferred; colon is the graft of choice when replacement is needed [e924-c26,e924-c28].