Clinical improvement

Repeat botulinum toxin as needed

Botulinum toxin injections

• Inject in four quadrants of anal sphincter

• Repeat every 3-6 months if needed

bSoiling after pull-through

History and physical examination

± rectal examination under anaesthesia

± anorectal manometry

Determining the extent of aganglionosis

Levelling biopsies and intraoperative pathology. The main goal of any surgical approach for HSCR is to remove the aganglionic segment and transition zone. The first step is to perform levelling biopsies to provide small samples of the bowel wall, either seromuscular or full-thickness, for examination to determine the presence or absence of ganglion cells. Biopsies should be well-oriented and adequately sectioned to confidently exclude ganglion cells and, if necessary, the process is repeated in a proximal direction until ganglion cells

are found. However, the presence of ganglion cells in a biopsy does not necessarily exclude the existence of a transition zone if partial circumferential aganglionosis, myenteric hypoganglionosis and/or submucosal nerve hypertrophy exist127. In short-segment HSCR, the transition zone is usually <5 cm, so resection or ostomy >5 cm proximal to a ganglionic biopsy usually encompasses the entire transition zone. However, in long-segment HSCR, the transition zone can be much longer. The use of appendectomy to diagnose total colonic aganglionosis is controversial, as aganglionic appendix in healthy neonates