Outcome of Perforated Necrotizing Enterocolitis in the Very Low-Birth Weight Neonate May be Independent of the Type of Surgical Treatment

Abstract

Perforated necrotizing enterocolitis (NEC) in the low-birth weight infant is now one of the most common surgical problems encountered in contemporary neonatal intensive care units. However, morbidity and mortality from NEC remain high, and the optimal surgical management of these infants remains controversial. Currently few data exist comparing the factors influencing outcome in very low-birth weight infants with perforated NEC treated by either local drainage or exploration. We hypothesize that survival of very low-birth weight neonates with perforated NEC may be more dependent on clinical status than on treatment modality. We present our experience treating a large cohort of infants weighing less than 1000 g with perforated NEC. A retrospective cohort study describes our experience with perforated NEC in very low-birth weight infants in a Level III neonatal intensive care unit. Between January 1991 and May 1998 a total of 70 newborn infants weighing less than 1000 g were evaluated and managed for perforated NEC. Comorbid factors were identified and calculated for each infant. Primary treatment was either local drainage or laparotomy. Statistical analysis was performed by Student's t test and multiple logistic regression. A multiple logistic regression model examined factors (comorbidities, number of comorbidities, and mode intervention) influencing outcome. A Kaplan-Meier survival analysis comparing survival versus number of comorbidities was performed. Twenty-two infants with an average weight of 679 g were treated by local drainage. Forty-eight infants with an average weight of 756 g were treated with exploratory laparotomy. Infants treated by local drainage had a higher cumulative number of comorbid factors (5.2 ± 0.50 vs 3.7 ± 0.29; P < 0.05) than those managed by operative exploration. Fourteen infants (63%) initially undergoing local drainage for perforated NEC survived. Of the 48 infants 36 operated on survived (75%). No single factor or combination of any comorbid factors was predictive of outcome. The total number of comorbidities for each neonate did reach statistical significance (P < 0.05). A greater likelihood of death was associated with a higher number of comorbidities. Survival with four or fewer comorbidities was 84 per cent, whereas survival with greater than six comorbidities was 30 per cent. The mean number of comorbidities was greater for drainage than for surgery, and for the same number of comorbidities the probability of survival tended to be greater for those treated with drainage than for those undergoing surgery. Multiple logistic regression analysis identified the total number of comorbidities as affecting outcome rather than treatment choice. This suggests therefore that selection of therapeutic options for the patient requires evaluating all factors that may impact survival rather than applying a single treatment strategy for all patients.