Incomplete resection of necrotic bowel may increase mortality in infants with necrotizing enterocolitis

Abstract

Background: Infants with advanced necrotizing enterocolitis (NEC) often need surgical resection of necrotic bowel. We hypothesized that incomplete resection of NEC lesions, signified by the detection of necrotic patches in margins of resected bowel loops, results in inferior clinical outcomes.

Methods: We reviewed the medical records of infants with surgical NEC in the past 15 years for demographic, clinical, and histopathological data. We also developed statistical models to predict mortality and hospital stay.

Results: Ninety infants with surgical NEC had a mean (±standard error) gestational age of 27.3 ± 0.4 weeks, birth weight 1008 ± 48 g, NEC onset at 25.2 ± 2.4 days, and resected bowel length of 29.2 ± 3.2 cm. Seventeen (18.9%) infants who had complete resection of the necrosed bowel had fewer (4; 23.5%) deaths and shorter lengths of hospital stay. In contrast, a group of 73 infants with some necrosis within the margins of resected bowel had significantly more (34; 46.6%) deaths and longer hospital stay. The combination of clinical and histopathological data gave better regression models for mortality and hospital stay.

Conclusion: In surgical NEC, incomplete resection of necrotic bowel increased mortality and the duration of hospitalization. Regression models combining clinical and histopathological data were more accurate for mortality and the length of hospital stay.

Impact: In infants with surgical NEC, complete resection of necrotic bowel reduced mortality and hospital stay. Regression models combining clinical and histopathological information were superior at predicting mortality and hospital stay than simpler models focusing on either of these two sets of data alone. Prediction of mortality improved with the combination of antenatal steroids, chorioamnionitis, and duration of post-operative ileus, with severity of inflammation and hemorrhages in resected intestine. Length of hospital stay was shorter in infants with higher gestational ages, but longer in those with greater depth of necrosis or needing prolonged parenteral nutrition or supervised feedings.

Figure 1.

Flow diagram shows eligible 118, excluded 28, and enrolled 90 infants.

Figure 2.

Hematoxylin and eosin-stained images (20x) of the small intestine resected from infants with NEC. These images show (a) less than 5% necrosis, 20% inflammation, and 30% hemorrhage; (b) fibrinous exudate, 15% necrosis, 20% inflammation, and congested vessels; (c) 70% necrosis, 40% inflammation, and 10% hemorrhage, and some vascular congestion. Panel (d) shows ileum resected from an infant with NEC. The rectangle is placed to highlight villus epithelial cells with regenerative changes. These cells show nuclear stratification and hyperchromasia, and amphophilic staining of the cytoplasm with both acid and basic dyes. Magnification bars = 150 μm.