Abstract
Background:
Neonatal intestinal obstruction is a challenging issue, especially in developing countries. There is an apparent difference in the etiology, complications, and mortality of intestinal obstruction in neonates in different countries.
Objectives:
We aimed to describe the causes, early postoperative outcomes, and predictors of morbidities in neonates with intestinal obstruction in a tertiary neonatal intensive care unit (NICU) in Iran.
Design & methods:
We conducted a retrospective study on neonates who were admitted with intestinal obstruction requiring surgery in the NICU of Boo-Ali Sina Hospital in northern Iran during 2018 to 2022. Demographic and clinical characteristics of the newborns, final diagnosis, postoperative complications, and mortality rate were documented. Also, the relationship between postoperative complications and risk factors, including birth weight, gestational age, and surgical intervention time, was evaluated.
Results:
A total of 169 neonates with intestinal obstruction requiring surgery were admitted with a male ratio of 60.9% and mean age of 3.85 ± 8.01 days. Imperforate anus with a prevalence of 42% was the most common cause of neonatal intestinal obstruction, followed by Hirschsprung’s disease and duodenal atresia. Death after surgery occurred in 4.1% of the patients. Sepsis with a prevalence of 1.4% was the most common early postoperative complication. The late surgical intervention had a statistically significant relationship with the increase in postoperative sepsis (P = .048).
Conclusion:
The time of surgical intervention is the main predictor of complications in neonatal intestinal obstruction, so prompt diagnosis and timely treatment of these babies can significantly improve the prognosis. It is also necessary to improve access to pediatric surgery services in developing countries.
Introduction
Neonatal intestinal obstructions are a common cause of admission to neonatal intensive care units and occur in 1 of 2000 live births.1,2 The most common reported causes of intestinal obstruction in neonates include anorectal malformation, duodenal atresia, jejunoileal atresia, Hirschsprung’s disease, meconium ileus, and meconium plug syndrome.3,4 The cardinal features of intestinal obstruction in newborns include bilious vomiting, failure to pass meconium on the first day of the newborn’s life, and abdominal distention.5,6 The diagnosis may be suspected before delivery due to prenatal ultrasound findings, including polyhydramnios or fetal double-bubble sign in duodenal atresia. 7
The pathological course of intestinal obstruction in newborns progresses rapidly and is poorly tolerated by most of them, but timely diagnosis and treatment lead to a better outcome.8,9 Most cases of intestinal obstruction in the neonatal period require surgical intervention, which is a challenging issue for this age especially in developing countries6,10,11 Neonates usually require surgical management by trained pediatric surgeons in tertiary care neonatal intensive care units. The availability of pediatric surgeons and/or tertiary NICUs may be limited in many countries and even when pediatric surgeons are available, neonates may develop post-operative complications such as anastomotic leakage, sepsis, and surgical site infection.9,12 When complications of neonatal intestinal obstruction occur, the mortality rate has been reported to be between 15 and 70%. 13 Factors that increase mortality include associated congenital abnormalities, late presentation, and prematurity. 6
A survey conducted in Iran showed that 56% of hospitals with NICU had pediatric subspecialists and 1 of the most important reasons for transferring neonates to other hospitals was the demand for surgery. 14
Considering the obvious difference in the etiology and mortality of intestinal obstruction in neonates in different regions of the world, there is a major need to identify the etiology and predictive factors that are not well revealed in our setting. Therefore, we aimed to determine the causes, early postoperative outcomes, and predictors of mortality in neonates with intestinal obstruction in our region.
Materials and Methods
This is a retrospective study that was conducted by reviewing the records of neonates who were admitted with intestinal obstruction requiring surgery in the Neonatal Intensive Care Unit (NICU) of Boo-Ali Sina teaching hospital during 2018 to 2022. The NICU of Boo-Ali Sina Hospital is a 17-bed level III referral unit affiliated with Mazandaran University of Medical Sciences in the north of Iran. One pediatric surgeon was working in this center during the study period. Approximately 250 to 300 neonates from the maternal hospital and other regional hospitals are admitted to this NICU every year.
Sample size
Considering that all the data and information related to the 5-year study period were collected, the sample size was estimated by the census method, and all the available files were fully investigated. All neonates who were diagnosed with intestinal obstruction by a neonatologist or a pediatric surgeon and underwent an operation were included in the study. Neonates who were admitted with a probable initial diagnosis of intestinal obstruction, but did not need surgical treatment in the follow-up evaluations, were excluded from the study.
Information related to the demographic and clinical characteristics of the newborns, final diagnosis, postoperative complications, and mortality rate were extracted and recorded from the files. Also, the relationship between postoperative complications and risk factors, including birth weight, gestational age, and surgical intervention time, was investigated.
Statistical analysis
Data analysis was done using SPSS version 24. Descriptive statistics including frequency, percentage, mean, and standard deviation were used to report the studied variables. Numeric data were compared with a t-test or Mann-Whitney U test, as appropriate. Student’s t-test was used to analyze the relationship between postoperative complications and risk factors. P-value < 0.05 was considered statistically significant.
Ethical consideration
All the information collected from the babies’ files was kept completely confidential.
Results
Baseline and clinical characteristics
During the study period, 169 neonates with intestinal obstruction requiring surgery were admitted. The mean and standard deviation of mothers’ age and gestational age were 27.93 ± 5.63 (range 14-44) years and 37.09 ± 2.55 (range 28-41) weeks, respectively. The mean and standard deviation of birth weight were 2884.85 ± 662.98 g with a maximum of 4300 g and a minimum of 1000 g. Most (103) babies in this study were male (60.9%).
The mean age of the patients when symptoms of obstruction appeared was 3.85 ± 8.01 days with a minimum of 1 and a maximum of 28 days. The duration of obstruction symptoms was 3.08 ± 4.55 days. The mean and standard deviation of the interval between admission and operation was equal to 2.86 ± 4.09 days. Seventeen cases (10.1%) were infants of diabetic mothers and 10 babies (5.9%) were twins. Fifty-six neonates were referred from centers in nearby cities outside the study hospital due to the lack of a pediatric surgeon. In addition, abnormalities in other organs were observed in 21 cases (12.4%) of infants. Polyhydramnios was reported in 17 (10.1%) of the mothers’ prenatal ultrasonography. Common clinical manifestations included abdominal distension in 64 (37.9%), failure to pass meconium in 42 (24.9%), and bilious vomiting in 17 (10.1%) babies, respectively.
Etiology
Imperforate anus with a prevalence of 42% was the most common cause of intestinal obstruction leading to surgery in the studied neonates, followed by Hirschsprung’s disease and duodenal atresia. Table 1 shows other different causes of intestinal obstruction in neonates during the study period.
Causes of intestinal obstruction in the neonates.
Abbreviation: NEC, necrotizing enterocolitis.
Post-operative complications
Out of all the babies who underwent surgery with intestinal obstruction, 7 cases (1.4%) had sepsis after surgery. Only 1 case had a surgical site infection (0.6%). Bleeding and shock were observed in 2 (1.2%) cases and 3 (1.8%) neonates had intestinal perforation after surgery. Of all the babies who underwent surgery, 15 cases required re-operation due to complications. Death after surgery occurred in 7 babies (4.1%). Two of the 3 babies who suffered post-operative intestinal perforation died, and both cases were caused by midgut volvulus accompanied by extensive small intestine necrosis.
Then, the relationship between the above complications with gestational age (Table 2), birth weight, and the time of surgical intervention was investigated (Table 3). A comparison of neonates who developed post-operative complications with those who did not showed no significant difference in different gestational ages. Among the investigated factors, the only statistically significant risk factor was late surgical intervention, which led to an increase in sepsis after surgery (P = .048). In fact, in neonates who were referred from other hospitals due to the lack of a pediatric surgeon, the mean and standard deviation of the time between the first symptoms of obstruction and surgical intervention was higher. Therefore, the rate of sepsis after surgery in these babies increased significantly.
Relationship of postoperative complications with gestational age.
Relationship of postoperative complications with birth weight, and surgery time.
Discussion
Results of our study showed that the most common cause of intestinal obstruction that led to surgery in neonates in our region was anorectal malformation, which was consistent with the results of studies conducted in Ethiopia, Uganda, India, and Bangladesh.3,15-17 Unlike ours, in the study conducted by Baad et al, Hirschsprung’s disease was the most common diagnosis in the imaging examination of neonates with intestinal obstruction. 18 Hirschsprung’s disease was observed as the second etiology of intestinal obstruction in our study. Hirschsprung’s disease is increasingly diagnosed in newborns in developed countries, while the reverse situation is still observed in developing countries.3,19
In our study, more males than females were reported which is similar to the findings observed in many other studies.3,6 This could be because there is a mild to moderate male preference in cases of Hirschsprung’s disease and anorectal malformation which were the most common causes of intestinal obstruction in our study.20,21 Associated anomalies in our study were found to be 12.4%, which was very similar to the report of Mohammad et al, 3 while other studies have reported a higher prevalence.22,23 The low prevalence of related congenital anomalies in this study can be due to some missed problems that will be revealed in post-neonatal investigations.
The average time for symptoms to appear in our patients was 3.85 days, which is in agreement with most previous studies.24,25 However, our results were contrary to the study reported by Cairo et al, wherein most of the babies presented with intestinal atresia after 7 days of age. 26 This indicates that the onset of presentation in intestinal obstruction is early and it is necessary to pay attention to symptoms, otherwise, it will lead to rapid deterioration of the baby’s condition.
About 21% of the neonates in our study had early postoperative complications and death occurred in about 4.1% of patients. The mortality rate of 4.1% observed in our study is low compared to various reported rates that ranged from 9.4 to 18.8%.5,6,10,16,27 Although the rate of complications in our study was lower than some previously reported studies from developing countries, the most common postoperative complication in our study was sepsis, which is similar to previous studies.3,5,6,10
What is interesting in our study is that the rate of postoperative complications was directly related to the time of surgical intervention. Indeed, cases, where the surgical intervention was delayed, had a higher morbidity rate. In our study, this delay occurred in cases where the baby was transferred to our center from nearby cities due to the lack of a pediatric surgeon or NICU beds. In the reports of developing countries such as sub-Saharan Africa, mortality and complications due to late presentation, poor transportation systems, and insufficient equipment are still high, which makes the management of neonates with intestinal obstruction very challenging in these countries. 27 Unlike other studies,5,28 birth weight and prematurity in our study were not associated with increased mortality. And this can be due to the significant improvement in the care of newborns, especially low birth weight and premature babies, that has been made in our NICU in recent years.
The strength of our study is that a larger sample size has been studied than most previous studies, but our study has some limitations. First, since our study was retrospective, we were unable to assess some more detailed information such as accurate diagnosis of associated anomalies. Second, the results of our study cannot include the epidemiological characteristics of other regions of Iran, so multicenter prospective studies are recommended.
Conclusion
Intestinal obstruction is 1 of the important causes of mortality and morbidity in neonates, and anorectal malformation is the most common etiology. Due to the significant impact of surgical intervention time with mortality and morbidity such as sepsis in these patients, prompt diagnosis and timely treatment of neonatal intestinal obstruction can significantly improve the prognosis of patients, especially in low-resource settings.
Footnotes
Acknowledgements
The authors would like to thank Zahra Shokri nurse in NICU for her assistance in data collection and the Clinical Research Development Unit (CRDU) of Boo Ali Sina Hospital, Mazandaran University of Medical Sciences for their support and cooperation throughout the study.
