The value of contrast studies in the evaluation of bowel strictures after necrotising enterocolitis

Strictures of the bowel are a frequent complication post-necrotising enterocolitis (NEC). Contrast studies are routinely performed prior to stoma closure following NEC. The aim of this study was to evaluate the ability of these studies to detect strictures and also directly compare them to operative and histological findings.

Two hundred and fourteen neonates who had a diagnosis of NEC (Bell stage 2 or greater) in a single unit (2007-2011) were analysed. Their case notes, radiology, and histology were reviewed.

One hundred and sixteen neonates underwent an emergency laparotomy and 77 had stomas fashioned. Sixty-six patients had a contrast study prior to stoma closure (distal loopogram 18, contrast enema 37, both studies 11). Colonic strictures were reported in 18 patients and small bowel strictures were reported in two patients. Fourteen of these colonic strictures were confirmed at operation and on histology but three colonic strictures were missed on contrast studies; one patient had had both contrast studies and the other two only a distal loopogram. Two small bowel strictures reported were confirmed and an additional small bowel stricture missed on distal loopogram was also detected at the time of operation. The incidence of post-op strictures was 19 out of 68 patients (27.9 %) and 16 (84.2 %) of these strictures were found in the colon. Contrast enemas had a much higher sensitivity for detecting post-NEC colonic strictures than distal loopograms; 93 versus 50 %, respectively; however, they are more likely to give a false positive result and therefore their specificity is lower; 88 versus 95 %, respectively.

Colon is the commonest site for post-NEC stricture and contrast enema is the study of choice for detecting these strictures prior to stoma closure.