Discussion
Etiological spectrum
Bowel obstruction among neonates, including those in our series, is mainly due to congenital origin.1–3 9 ARM was the leading cause in our series, which agrees with reports from other series though not in others in which JIA was the most common cause.2–4 16 20 We also noticed that many with ARM reported within 3 days of life, the fact that most of them, especially those with no perianal fistula get early symptoms. This result concurs with other related reports too.7 10 In addition, most neonates with ARM were delivered at term, with a male-to-female ratio of 5:1, which agrees with many authors as well.5 13
JIA was second highest cause of bowel obstruction, although it predominated among cases of atresia, which was concordant with reports in other series with a male-to-female ratio of 1:1.7–9 JIA is believed to be a common finding among the premature which is about the same as ours, where about 44% were preterm.4 21 Similarly, presentation in atresia is usually early, within 7 days, and this was in agreement with our findings in which most cases of JIA presented within 3 days with exception of a few cases of duodenal atresia who presented after their third day, though would still be within 7 days.21–23 We think that the early onset of symptoms and rapid deterioration of the patient’s condition in atresia is the probable cause of early presentation. These findings, however, were not in agreement with the report by Cairo et al, wherein many neonates with intestinal atresia presented after day 7.18
HD, on the other hand, was a major cause of obstruction in other reports, but in our study the incidence was low.4 11 A study conducted by Saha et al showed a 35.3% incidence of HD, higher than that of atresia, whereas in other related studies the incidence was almost equal, with HD leading over atresia.3 10 11 In this series, all cases of HD were male; and most termed, a concordant finding with other literature, where HD was found to be more common among male babies.12 22 However, most cases of HD presented late, with a median age of 12 days, which is later than the median age of 6 days in similar series.3 8 Presentation in HD is usually delayed owing to variability in the onset of symptoms and lack of specificity. This may lead to increased morbidity, though the prognosis is good even in late presenters because decompression is often done repeatedly by doing enema at peripheral centers.
Malrotation was the fifth leading cause with a male-to-female ratio of 1.5:1, a fewer incidence than in other reports, though about the same in some.5 11 21 Most malrotation cases presented within the first 3 days of life, but this result does not agree with related series where neonates with malrotation were termed late presenters.13 14 On the other hand, neonates with NEC usually present late, as in our series, where many presented after the third day.7 14 As in JIA, NEC is common among premature, a finding that agrees with ours, with a male-to-female ratio of 1.5:1. In our series, many with NEC were on mixed feeds.11 24
Meconium ileus was one of the most common causes of obstruction as noted by Saha et al, whereas cases of meconium ileus were quite a few in ours.11 This could be due to the low incidence of cystic fibrosis in the region, which is usually the cause of meconium ileus. Other less common causes of bowel obstruction in our series included obstructed hernia and bowel stenosis as in other series.4 5 11 13 Overall, in our series ‘low’ obstruction was observed more often than the ‘high’ types, unlike in others.12 14 We do not have a clear reason for this and hence may require validation with subsequent studies.
Early postoperative outcomes
About 55% of the neonates in our series developed complications in the early postoperative period, which concurs with related series in sub-Saharan Africa, though does not agree with the report from high-income countries.5 11 14 21 25 Of these, nearly 69% died and only 31% were discharged alive. However, close to 15% of the neonates without complications died as well. This result was attributed to neonates which died in the immediate postoperative period, probably as a result of anesthesia-related complications. Others could be due to complications, such as prematurity, severe congenital anomalies, or inadequate optimization before surgery.
We noticed higher morbidity among cases of NEC and malrotation, as in other series where most of these cases were late presenters with the risk of poor prognosis as a result of repeated vomiting and electrolyte imbalances.19 26 In addition, most of these were referrals from peripheral health facilities, where services are not equipped to detect obstruction at an early stage leading to delayed presentation. Similarly, neonates with JIA also had higher morbidity, as most of these were neonates premature; thus, the risk of dying during the perioperative period was probably due to complications associated with prematurity. This concurs with reports from related series.15 26
At least 50% of neonates in our series developed persistent fever after 24 hours of surgery, attributed to sepsis; commonly among cases of NEC and HD, a finding quite high compare to other series.12 24 Neonates with NEC often present with sepsis following peritonitis; and if not optimized well, will have fever in the postoperative phase. Meanwhile those with HD, despite being late presenters with the risk of sepsis, do get HD-associated enterocolitis which may present with fever too. However, mild postoperative fever (<38°C) could be due to physiological changes, especially within 48 hours of surgery.
Nearly 16% of neonates in our study had surgical site infection, commonly among cases of JIA and HD, which was in line with findings from related studies.5 21 The explanation could be due to poor hygiene and improper wound care because most of these neonates were mainly born to first-time mothers. On the other hand, the few who developed anastomotic leaks were mostly among cases of JIA and malrotation because most of these underwent resection and anastomoses.
Electrolyte imbalances also have been reported as a major outcome.5 13 In our series, many presumably died due to electrolyte derangement, though we think the actual figure could be less than what was reported because most of the time we practice rigorous preoperative correction of the deficit. However, many had features of sepsis, and yet the majority of neonatal sepsis has electrolyte abnormalities; hence, some could have had electrolyte imbalances and died unnoticed.
The mortality due to bowel obstruction among neonates ranges between 21% and 45% in low-income and middle-income countries, unlike <15% in Europe.25 26 In our series, the mortality was about 45%, which is within the above range. However, a similar report by Hanif et al, observed postoperative mortality of 15.4%, just like a finding from a study conducted by Islam et al in which mortality of 20.8% was reported.14 22 In the same context, Ullrich et al also noted a postoperative mortality rate of 37% and 38% among cases of ARM and JIA, respectively.16 However, in our series, we noticed higher mortality among cases of JIA and NEC. These were the same categories who developed fever and anastomotic leak after surgery, in addition to some of them being premature.
Predictors of mortality
Neonates with fever at admission, attributed to sepsis, had less chance of survival. This result agrees with that of other authors where sepsis was a major predictor of mortality.5 10 11 13 24 Premature babies also had a poor prognosis, as in other series, because these babies are prone to hypothermia, hypoglycemia, and sepsis.14 26 27 Similarly, neonates who presented within the first 3 days of life were more at risk of dying because being early presenters may indicate a very severe symptoms that making them prone to complications in the early postoperative phase. However, because in most series the mortality rates were higher in late presenters, this may require further validation with subsequent studies.4 14 21 22 25 Most neonates from primipara mothers in our series had lower survival rate. As hinted at by Kidus et al, most first-time mothers do not know how to care for the newborn, especially during the perioperative period.28 In the same way, we noted that neonates on mixed feeds had higher mortality too because they are usually prone to NEC, especially the extremely low birth weight, as was noted by Colaizy et al.29 Furthermore, the type of surgery performed affects the outcome, where stoma placement is associated with a reduction in mortality, especially in intestinal atresia.4 21 This was not the case in our study. We had many with a stoma but still had unacceptably high mortality, though these were primarily for the cases of ARMs as the initial treatment care. The anastomotic leak, unlike in our series, has been noted as a major predictor of mortality. A baby who develops a leak carries a risk of sepsis as well as electrolyte derangement.10 19 Similarly, the anastomotic leak has also been linked to the cadre of healthcare providers who do these operations.4 10 In line with that, Rhee et al noted that most neonates operated on by pediatric surgeons have less risk of anastomotic leak, with a better outcome, which is a similar finding in our series.30
Obstruction in association with multiple congenital anomalies, though not present in our study, has been reported in other series as a major predictor of mortality.10 11 13 14 21 Neonates with congenital heart defects pose challenges to the anesthesia team because some of these neonates may require prolonged respiratory support. Causes of obstruction and the duration of surgery have also been noted by other authors as predictors of mortality.5 12 We did not notice these, comparable to report of other authors.15 19 24
In conclusion, anorectal malformation is still the leading cause of bowel obstruction yet morbidity and mortality among these neonates is unacceptably high with the major predictors of mortality being age at presentation, prematurity, fever at admission, mothers’ parity, and breastfeeding status.
Limitations
Selection bias could have been introduced into the study by non-probability sampling. However, this bias was kept at a minimum because there was no loss to follow-up. The type of obstruction, as well as the surgery performed, could have affected the outcome in these neonates, though was catered for at the analysis level. The findings in this study may not be representative of all the neonates with bowel obstruction in the region due to limited sample size and hence may require a multicenter study for validation.
Recommendations
We recommend that premature neonates and neonates with fever at admission need to be optimized properly prior to surgery, and preferably they need to be operated on by pediatric surgeons. Further studies should be conducted to confirm the validity of the major predictors of mortality that we identified. This will help in reducing any bias in our conclusions due to limited sample size of our study.
