Optimal treatment for necrotizing enterocolitis still unclear

Necrotizing enterocolitis (NEC) is the most common and serious gastrointestinal disease a premature infant faces. As more, smaller preterm infants survive, incidence of NEC, a surgical emergency, continues to increase, while the 30% to 50% mortality rate remains unchanged.

Optimal treatment is uncertain. The standard approach to perforated intestine, necrotic intestine, or both is surgical bowel resection with creation of stomas. “Laparotomy entails substantial risks in a critically ill infant weighing 500 g,” says UAB pediatric surgeon Douglas C. Barnhart, MD, MSPH. The alternative — primary peritoneal drainage (PPD) — is significantly less invasive. It involves placing a drain into the peritoneal cavity through a small abdominal incision. However, experts have continued to debate which procedure is preferable, with little evidence to indicate the superiority of one approach over the other. “If you surveyed hospital to hospital, surgeon to surgeon, you would find strong biases, despite the absence of evidence,” he says.

No Survival Advantage
Barnhart, along with UAB neonatologist Reed A. Dimmitt, MD, DVM, MSPH, and others in the United States and Canada recently participated in a randomized clinical trial to determine whether PPD improved 90-day postoperative survival compared with laparotomy and resection (N Engl J Med 2006;354:2225-2234).

Fifteen neonatal intensive care units participated, evaluating survival rates in 117 very low birth weight (<1500 g) premature infants with perforated NEC. Investigators also assessed the difference in frequency of total parenteral nutrition and the length of hospital stay in surviving infants. “We found no significant variations in mortality, feeding, or length of hospitalization among infants who underwent laparotomy and resection compared with PPD,” Dimmitt says.Clinicians have used PPD in unstable lower weight babies assuming they could not tolerate laparotomy and might have better outcomes after PPD. In addition to refuting that belief, study investigators found no advantage to laparotomy for heavier premature infants, though the significance of that finding is limited by the trial’s small number of participants.

Surgeons have used PPD as a temporizing procedure followed by laparotomy, but observational studies indicate higher mortality rates with this approach. Moreover, comparison of clinical status in the first days after PPD between patients who survived and those who did not shows no difference, so that there is no reliable way to predict which infants are better suited to PPD and which will require salvage laparotomy.

“It is frustrating not to see a difference in survival, but now that we know these babies tolerate laparotomies without increased mortality, surgery becomes our procedure of choice,” Barnhart says, adding that laparotomy does have advantages. Surgeons can determine disease severity in involved intestines and can inform families immediately. With drainage, surgeons may not be aware of the extent of damage until they attempt a reconstruction. Creating a stoma also may stabilize healthier infants, Barnhart says.

“This is the first randomized trial on an emergent surgical procedure in infants. Surgeons need additional clinical trials investigating these kinds of difficult questions,” he says.

For more information
Dr. Douglas Barnhart
Dr. Reed Dimmitt
1.800.UAB.MIST
mist@uabmc.edu