Primary anastomosis versus staged enterostomy for post-necrotizing enterocolitis intestinal stricture in infants: a propensity score-matched cohort study and prediction model

Post-necrotizing enterocolitis (NEC) intestinal stricture is an important late complication among NEC survivors. Surgical management commonly involves primary anastomosis (PA) or staged enterostomy (SE), but comparative evidence in this population remains limited. We compared postoperative outcomes after PA and SE and developed a model to estimate the risk of prolonged postoperative length of stay (LOS). This single-center retrospective cohort study included 280 infants who underwent surgery for post-NEC intestinal stricture between January 2017 and December 2025. Outcomes after PA and SE were compared before and after 1:1 propensity score matching, with exact matching by sex and a caliper width of 0.2 standard deviations of the logit of the propensity score. Prolonged postoperative LOS was operationally defined as 19 days or longer, corresponding to the 75th percentile of the cohort rather than a validated universal clinical cutoff. Multivariable logistic regression was used to identify predictors of prolonged LOS and to develop a risk prediction model. Overall, 194 infants underwent PA and 86 underwent SE. After matching, 73 pairs were retained, and all absolute post-matching standardized mean differences were 0.17 or lower. In the matched cohort, PA was associated with a longer operative duration than SE (median, 96 vs. 90 min; P < 0.001), a similar time to enteral feeding (median, 7 vs. 7 days; P = 0.756), a shorter postoperative LOS (median, 15 vs. 18 days; P = 0.038). Individual major complications, including anastomotic leakage, were uncommon and did not differ significantly between groups, although the composite incidence of early postoperative complications was lower after PA (4.1% vs. 15.1%; P = 0.039). In multivariable analysis, SE was associated with higher odds of prolonged postoperative LOS (adjusted odds ratio, 2.94; 95% confidence interval, 1.52–5.71; P = 0.001). The prediction model showed acceptable discrimination (area under the receiver operating characteristic curve, 0.780; 95% confidence interval, 0.736–0.854). Among selected infants with post-NEC intestinal stricture, PA was associated with a shorter initial postoperative hospitalization and a lower composite rate of early postoperative complications than SE after adjustment for measured baseline differences; however, individual adverse-event rates did not differ significantly. SE remains necessary when immediate anastomosis is unsuitable. The prediction model is preliminary and should not be implemented in routine clinical practice until it has undergone external multicenter validation.