BACKGROUND A large proportion of patients with Hirschsprung disease experience persistent obstructive symptoms after corrective surgery. Persistent obstructive symptoms may result in faecal stasis that can develop into Hirschsprung-associated enterocolitis, a potential life-threatening condition. Important treatment to improve faecal passage is internal anal sphincter relaxation using botulinum toxin injections. AIM To give an overview of all empirical evidence on the effectiveness of botulinum toxin injections in patients with Hirschsprung disease. METHODS A systematic review and meta-analysis was done by searching PubMed, EMBASE and the Cochrane Library, using entry terms related to: (1) Hirschsprung disease; and (2) Botulinum toxin injections. 14 studies representing 278 patients met eligibility criteria. Data that were extracted were proportion of patients with improvement of obstructive symptoms or less enterocolitis after injection, proportion of patients with adverse effects and data on type botulinum toxin, mean dose, average age at first injection and patients with associated syndromes. Random-effects meta-analysis was used to aggregate effects and random-effects meta-regression was used to test for possible confounding factors. RESULTS Botulinum toxin injections are effective in treating obstructive symptoms in on average 66% of patients [event rate (ER) = 0.66, P = 0.004, I 2 = 49.5, n = 278 patients]. Type of botulinum toxin, average dose, average age at first injections and proportion of patients with associated syndromes were not predictive for this effect. Mean 7 duration of improvement after one botulinum toxin injections was 6.4 mo and patients needed on average 2.6 procedures. There was a significant higher response rate within one month after botulinum toxin injections compared to more than one month after Botulinum toxin injections (ER = 0.79, vs ER = 0.46, Q = 19.37, P < 0.001). Botulinum toxin injections were not effective in treating enterocolitis (ER 0.58, P = 0.65, I 2 = 71.0, n = 52 patients). There were adverse effects in on average 17% of patients (ER = 0.17, P < 0.001, I 2 = 52.1, n = 187 patients), varying from temporary incontinence to mild anal pain. CONCLUSION Findings from this systematic review and meta-analysis indicate that botulinum toxin injections are effective in treating obstructive symptoms and that adverse effects were present, but mild and temporary.

Introduction: Hirschsprung-associated enterocolitis (HAEC) accounts for substantial morbidity and mortality in patients with Hirschsprung disease (HD). The aim of this study was to identify incidence of preand postoperative HAEC in our consecutive cohort and to identify patient and clinical characteristics that are associated with developing postoperative HAEC and HAEC-free interval. Material and methods: A retrospective cohort study was performed with all 146 HD patients treated between 20 0 0 and 2017. Data were retrieved from the medical records. HAEC was defined as presence of clinical signs of bowel inflammation, that required treatment with intravenous antibiotics and admittance to the hospital during at least two days. To identify risk factor for HAEC, patients with and without a history of postoperative HAEC were compared. Kaplan-Meier and Cox-regression were used to assess HAEC free intervals before and after surgery. Results: Out of 146 patients, 12 patients had pre-operative HAEC (8%) and 31 patients had postoperative HAEC (21%). Median preoperative HAEC free interval was 112 days (IQR 182 days). Length of hospital stay due to readmissions was longer for patients with a history of postoperative HAEC compared to patients without a history of postoperative HAEC (9.5 vs 16 days, U = 1872.5, p = 0.047). Median postoperative HAEC free interval was 226 days. Of the patients who had postoperative HAEC, 66% had their first episode within the first year after surgery and that the incidence of HAEC declined over follow-up. Conclusions: HAEC incidence was relatively low in our population. No patient or clinical characteristics were associated with the risk of postoperative HAEC.