Two Ways to Operate on a Tiny Belly: What a Major Trial Learned About Which One Is Better

A plain-language guide to the Necrotizing Enterocolitis Surgery Trial and what its follow-up studies found about breathing and growth

When one of the smallest premature babies develops a hole or dying tissue in the intestine, surgeons must choose quickly between two operations: a small bedside tube that drains the belly, or a full operation to open the abdomen and remove the damaged bowel. For years no one knew which choice gave babies the best chance of surviving and growing up healthy. A large United States trial has now shown that the better choice depends on why the bowel is failing — and two 2024 follow-up studies revealed that this single surgical decision can also affect a baby's lungs and growth for years afterward. This article explains, in everyday language, what the research found and what it means for families.

What is going wrong inside the belly

Two serious problems can force this decision. The first is necrotizing enterocolitis, usually shortened to NEC — a condition in which parts of a premature baby's intestine become inflamed and can begin to die [1]. The second is spontaneous intestinal perforation, or SIP — a single hole that opens in the bowel, often without the widespread tissue death seen in NEC. Both spill intestinal contents into the abdomen, both are emergencies, and both are most dangerous in the tiniest babies, those born weighing less than about 2.2 pounds (1000 grams). In these smallest infants, a bowel emergency is one of the most life-threatening events that can happen in a newborn intensive care unit [2]. Because NEC and SIP are different problems, it makes sense that the best way to treat them surgically might differ too — but proving that took decades.

How families and doctors used to face this choice

For a long time, the choice between a drain and a full operation came down to a surgeon's judgment and a baby's momentary stability, because the research could not settle it. In 2006, a large study in the United States and Canada compared the two approaches and found that roughly the same number of babies survived either way, which made the simpler bedside drain look like a legitimate option rather than just a stopgap [3]. A few years later, a study in the United Kingdom reached a similar survival conclusion but noticed that many babies who received a drain ended up needing the bigger operation anyway [4]. Neither study was large enough to answer the question parents care about most — not just whether a baby survives, but whether the baby grows up able to learn, move, and thrive. So guidelines stayed silent, practice varied from hospital to hospital, and families were often told, honestly, that doctors did not know which operation was best. That is the uncertainty the newest trial set out to end.

The trial that finally compared the two operations

The study is called the Necrotizing Enterocolitis Surgery Trial, or NEST [5]. Researchers at 20 hospitals across the United States, part of a large national research network run by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, enrolled 310 extremely small premature babies who needed surgery for NEC or SIP. Each baby was randomly assigned — like a carefully supervised coin flip — to start with either the bedside drain or the full operation (called a laparotomy). The researchers then followed the children to about two years of age to see how many had died or had a significant developmental delay.

At first glance, the two operations looked equally good: about 69 out of every 100 babies in the operation group and 70 out of every 100 in the drain group had died or had a developmental delay by age two — essentially a tie. But the researchers had planned to look deeper, and there they found the key result. The best choice depended on the baby's diagnosis. For babies whose problem was NEC, the full operation was clearly better: 69 out of 100 had died or had a delay after the operation, compared with 85 out of 100 after the drain. The trial's statistics estimated a 97% chance that the full operation was the better choice for NEC. For babies whose problem was SIP, the two approaches came out about even, so starting with a drain was a reasonable choice. In short: for NEC, open and operate if the baby can tolerate it; for SIP, a drain is a fair way to begin.

The surprise: the choice reaches the lungs

You might expect an operation on the belly to affect only the belly. But one of the 2024 follow-up studies found that it can also affect a baby's lungs [6]. Babies who started with a drain needed the breathing machine (a ventilator) for longer after surgery, and were more likely to be treated with steroid medicines for their lungs. Many premature babies develop a chronic lung condition called bronchopulmonary dysplasia, a kind of lung injury that leaves the lungs needing extra support and time to heal [7], [8]. The overall rate of the most severe lung disease was not clearly different between the two groups. But drained babies were more likely to be sent home on breathing monitors and to be readmitted to the hospital for breathing problems during their first two years. And among the small group of babies who did develop the most severe lung disease, those who had been drained were far more likely to have developmental delays than those who had the full operation. Doctors think the explanation may be that a drain does not clean out the infection and inflammation as completely as an operation does, and that lingering inflammation can harm both the lungs and the developing brain. This part of the research is an early clue rather than a firm conclusion, but it fits together in a sensible way.

The other lasting cost: growth

The second 2024 follow-up study looked at how these children grew, and the findings are important for families to hear honestly [9]. Growing well is hard after major bowel surgery in a tiny baby. Among the survivors, about half of the NEC children and just over 40% of the SIP children were significantly underweight for their age at two years — far more than would be expected in other children — and about three-quarters were shorter than expected for their age. NEC children were also more likely to develop "short bowel syndrome," meaning too little working intestine to absorb nutrition normally, and to depend for a long time on nutrition given through a vein. These growth struggles have been seen in earlier studies of NEC survivors too [10], [11]. Within the NEC group, babies who started with a drain also tended to take longer to begin and reach full milk feeds than those who had the operation — another sign pointing the same direction. The message is not that good growth is impossible, but that slow growth after this kind of surgery is common and expected — something the care team should watch closely and support with extra nutrition and follow-up, not something families should blame themselves for. Many of these children go home still needing feeding support, such as nutrition through a vein or a feeding tube, and catch-up can continue for months or years with patient, specialized care.

What this means for your baby and your family

If your baby faces this surgery, a few things are worth understanding. First, the care team will work hard to determine whether the problem is NEC or SIP, because that diagnosis now genuinely guides which operation to do first. Second, choosing a drain for SIP does not mean "nothing more will be needed" — it is a reasonable starting point, and a full operation can still follow if the baby does not improve. Third, if your baby has NEC and is drained because they are too unstable for a bigger operation right away, that is a decision about safety in the moment, and the team will continue to reassess. Finally, it helps to know that today's national data give an honest picture of both the seriousness and the real range of outcomes for extremely premature babies, so that hope and realism can sit side by side [12]. Your team can walk you through where your own baby fits.

What researchers are working on next

Scientists now want to prove the "why" behind these findings. If a drain really does leave behind more inflammation, future studies can measure that inflammation directly, track exactly how steroid medicines are used, and test better ways to help the intestine recover and the baby grow after NEC surgery [13]. Understanding NEC itself — why some premature intestines tip into this dangerous inflammation — remains a major research focus that could eventually help prevent the emergency in the first place. For now, families can take some reassurance from a hard-won piece of clarity: after decades of uncertainty, doctors finally have solid evidence about which operation to choose, and a clearer picture of what to watch for in a child's breathing and growth in the years that follow.

References

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  2. Fitzgibbons SC, Ching Y, Yu D, et al. Mortality of necrotizing enterocolitis expressed by birth weight categories. J Pediatr Surg. 2009;44(6):1072–1075. doi:10.1016/j.jpedsurg.2009.02.013 ↩
  3. Moss RL, Dimmitt RA, Barnhart DC, et al. Laparotomy versus peritoneal drainage for necrotizing enterocolitis and perforation. N Engl J Med. 2006;354(21):2225–2234. doi:10.1056/NEJMoa054605 ↩
  4. Rees CM, Eaton S, Kiely EM, Wade AM, McHugh K, Pierro A. Peritoneal drainage or laparotomy for neonatal bowel perforation? A randomized controlled trial. Ann Surg. 2008;248(1):44–51. doi:10.1097/SLA.0b013e318176bf81 ↩
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  7. Thébaud B, Goss KN, Laughon M, et al. Bronchopulmonary dysplasia. Nat Rev Dis Primers. 2019;5(1):78. doi:10.1038/s41572-019-0127-7 ↩
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  9. Speer AL, Lally KP, Pedroza C, et al. Surgical necrotizing enterocolitis and spontaneous intestinal perforation lead to severe growth failure in infants: a preplanned secondary analysis of the Necrotizing Enterocolitis Surgery Trial. Ann Surg. 2024;280(3):432–443. doi:10.1097/SLA.0000000000006378 ↩
  10. Hong CR, Fullerton BS, Mercier CE, et al. Growth morbidity in extremely low birth weight survivors of necrotizing enterocolitis at discharge and two-year follow-up. J Pediatr Surg. 2018;53(6):1197–1202. doi:10.1016/j.jpedsurg.2018.02.085 ↩
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