Discussion

Temporary enterostomy formation is a common, often life-saving management strategy for a number of congenital and acquired surgical conditions in infants. Enterostomy-related complications are encountered in a significant number of patients but those infants who are most at risk are poorly defined. In addition, published data relating to the optimal timing of enterostomy reversal are confusing, particularly with regard to the potential effect of an enterostomy on growth and weight gain such that some argue for late enterostomy reversal while others make the case for early closure with data to support either view.4 ,6 The application of standardised growth charts and z scores is a well-described method of measuring and quantifying growth during development but this technique has not been previously used to explore the relationship between enterostomy complications and timing of closure previously.10 This study reviews complications encountered in infants with small bowel enterostomies and uses z scores to assess growth before and after enterostomy reversal. A limitation of using z scores to assess growth is that it is unclear whether weight gain is true growth or extra weight such as fluid; however, when multiple weights are measured weeks apart, as in this study, it is more likely to be due to true growth.

The study finds that complications related to small bowel enterostomies are significantly more likely in infants of low birth weight and those of low gestational age at birth, the majority of which had NEC. Unfortunately with the numbers in each group it is not possible to perform regression analysis to differentiate between NEC and low gestational age. These infants were also more likely to remain in hospital and require PN prior to enterostomy closure. In the group with complications, the enterostomies were closed earlier (14.5 vs 19.1 weeks), which is likely to be related to difficulty establishing exclusive enteral feeding with concomitant PN dependence, as well as comorbidities such as chronic lung disease, which ultimately combine to prevent hospital discharge. The presence of an enterostomy-related complication is also likely to have influenced the timing of enterostomy closure in some infants although this decision was not always documented clearly in the medical records.

Published neonatal enterostomy complication rates range from 18% to 68% and the complication rate in this series was 41%.3 ,6 ,11 ,12 Several prior studies have sought risk factors for enterostomy-related complications. Singh et al12 found no risk factors but both Lee et al6 and Aguayo et al11 identified younger gestational age and smaller preoperative weight as significant risk factors. This study concurs with these two authors as complications related to small bowel enterostomies are significantly more likely in infants of low birth weight and low gestational age. Such infants, most of whom had NEC, were more likely to remain in hospital and require PN prior to enterostomy closure. Although the development of complications is multifactorial, these data highlight which patients are likely to require longer inpatient stays and the added risks that this brings. Indeed, Lee et al6 found a lower enterostomy complication rate in those with an enterostomy for a shorter period of time. A notable negative finding from this study is that siting the enterostomy through the laparotomy incision did not affect the complication rate. This is consistent with a previous study by Kronfli et al13 despite their hypothesis that those sited through a separate incision are less likely to develop infection.

A number of studies have sought to determine the optimal time to close enterostomies in infants.4 ,6 ,8 ,11 ,14 While some argue for early closure, from a weight of 1.9 kg,4 others report quite contrary views, with one study reporting that a closure weight below 2.66 kg is a significant risk factor for complications including poor growth.6 A more recent study of patients with NEC found that enterostomy reversal before 10 weeks postformation resulted in longer inpatient stay and prolonged use of PN compared with those reversed later, although they report no difference in enterostomy complications or mortality.15 Another centre reports reversal of NEC stomas at 8–10 weeks regardless of patient weight.14 It is notable that the systematic review of enterostomy closure following surgery for NEC performed by Struijs et al8 found no evidence to support either early or late enterostomy closure. In our centre, a ‘rule of thumb’ principle is used to guide the timing of closure, which includes a minimum time of 6 weeks from enterostomy formation and a preferred minimum weight of 2.5 kg. However, other factors are considered such as the need for ongoing tertiary neonatal care (such as respiratory support) and exceptions are made in those infants clearly compromised by situations such as a ‘high’ enterostomy with large volume output or a complication that renders enterostomy care challenging. These factors, along with an infant's standardised weight-for-age trend, should be used when considering the timing of enterostomy reversal.

Short-term weight gain on its own has previously been shown following ileostomy closure in NEC but standardised growth was not taken into account.4 We found a significant improvement in z score following enterostomy reversal regardless of gestational age at birth, underlying diagnosis or presence of enterostomy-related complications. This offers reassurance regarding growth in these patients who have often failed to thrive in early life. The data support consideration of early restoration of intestinal continuity in neonates with growth failure with the caveat that this decision must be balanced against the risks of early closure such as reoccurance in NEC.

This work has a number of limitations due to its retrospective nature, the content of data recorded in case notes and the heterogeneous patient group. Additionally, individual patient management was tailored by their consultant; data on issues such as perioperative management, the overall condition of the infant at the time of enterostomy formation, and availability of operating theatre time were considered unfeasible to collate in retrospect. Despite this we find that smaller, younger infants are more susceptible to enterostomy-related complications, in keeping with a number of other studies. We have also shown that the reversal of enterostomies allows infants to thrive in terms of weight gain on a standardised growth chart. Ideally more data are needed from prospective studies to confirm this finding and determine any other relevant prognostic factors.