Mortality in micro-premature infants with necrotizing enterocolitis treated by primary laparotomy is independent of gestational age and birth weight

Previous reports indicate that mortality in micro-premature infants with surgical necrotizing enterocolitis (NEC) is inversely proportional to gestational age and birth weight. We have observed that patterns of survival in micro-premature infants with NEC appear to be changing and may be influenced by the use of primary laparotomy (PL). Thirty-one infants <1,500 g who underwent surgery for NEC were classified into two subgroups: extremely low birth weight infants <1,000 g (ELBW, N = 17) and very low birth weight infants 1,000–1,500 g (VLBW, N = 14) and the groups were compared. Data were retrospectively collected and analyzed using Chi-square or Fisher’s exact tests for categorical variables and Wilcoxon rank sum test for continuous variables. All 31 patients (100%) had radiographic evidence of pneumatosis intestinalis and all had operative findings of intestinal necrosis while 20/31 (67%) had intestinal perforation. Surgical mortality was 25% (7/28). Three additional patients died greater than 3 months after surgery of causes unrelated to NEC or surgery yielding an overall mortality of 32% (10/31). There were no significant differences in mortality between ELBW and VLBW patients (P = 0.42). The only variables associated with increased mortality were pannecrosis and longer segment of necrotic bowel (P = 0.005). In our neonatal unit, the mortality of micro-premature infants less than 1,500 g with surgical NEC appears to be independent of gestational age and birth weight. Although the small sample size may mitigate the validity of this study, we found that the most important determinants of mortality were pannecrosis and longer length of necrotic bowel.