Should primary anastomosis be considered more? A retrospective analysis of anastomotic complications in young children.

Objective: Little is known about intestinal anastomotic leakage and stenosis in young children (≤3 years of age). The purpose of this study is to answer the following questions: (1) what is the incidence of anastomotic stenosis and leakage in infants? (2) which surgical diseases entail the highest incidence of anastomotic stenosis and leakage? (3) what are perioperative factors associated with anastomotic stenosis and leakage? Methods: Patients who underwent an intestinal anastomosis during primary abdominal surgery in our tertiary referral centre between 1998 and 2018 were retrospectively included. Both general incidence and incidence per disease of anastomotic complications were determined. Technical risk factors (location and type of anastomosis, mode of suturing, and suture resorption time) were evaluated by multivariate Cox regression for anastomotic stenosis. Gender and American Society of Anaesthesiology (ASA) score of ≥III were evaluated by χ2 test for anastomotic leakage. Results: In total, 477 patients underwent an anastomosis. The most prominent diseases are intestinal atresia (30%), Hirschsprung's disease (29%), and necrotizing enterocolitis (14%). Anastomotic stenosis developed in 7% (34/468) of the patients with highest occurrence in necrotizing enterocolitis (14%, 9/65). Colonic anastomosis was associated with an increased risk of anastomotic stenosis (hazard ratio (HR) =3.6, 95% CI 1.8 to 7.5). No technical features (type of anastomosis, suture resorption time and mode of suturing) were significantly associated with stenosis development. Anastomotic leakage developed in 5% (22/477) of the patients, with the highest occurrence in patients with intestinal atresia (6%, 9/143). An ASA score of ≥III (p=0.03) and male gender (p=0.03) were significantly associated with anastomotic leakage. Conclusions: Both anastomotic stenosis and leakage are major surgical complications. Identifying more patient specific factors can result in better treatment selection, which should not solely be based on the type of disease.

Diagnostic accuracy of ultrasonography to distinguish thyroglossal duct cysts from dermoid cysts in children with a midline neck swelling.

INTRODUCTION: Midline neck swellings are very common in children and mostly caused by thyroglossal duct cysts (TGDCs) or dermoid cysts (DCs). Since DCs can undergo simple excision, whilst TGDCs demand more thorough resection via Sistrunk procedure, it is important to differentiate between both pre-operatively. Previous studies have suggested an ultrasound-score (SIST) based on presence of septae, wall irregularity and solid components could do so. This study aims to evaluate the diagnostic accuracy of this score. METHODS: All patients (≤18 years) undergoing surgery between 2006 and 2018 for a midline neck mass at our tertiary centre with a histopathological diagnosis of TGDC or DC were retrospectively included. The pre-operative ultrasound was evaluated by an experienced radiologist and the SIST as well as location, tract, echogenicity, margin and multilocularity were scored. RESULTS: We included 97 children, of whom 67 (69 %) with TGDCs. The SIST showed a sensitivity of 37 %, specificity of 97 %, a positive predictive value of 96 % and a negative predictive value of 35 % for the SIST-score in detecting TGDCs, which resulted in an AUC of 0.67. In addition, internal echogenicity (P < 0.01) and margin definition (P < 0.01) were significantly associated to TGDC diagnosis whilst location and multilocularity were deemed insignificant following Bonferroni correction. CONCLUSION: We conclude that the SIST-score seems very capable to rule in TGDC. However, the SIST-score is far from making a clear distinction between DC and TGDCs preoperatively. The addition of other ultrasound variables, such as margin definition and echogenicity, might increase the diagnostic accuracy and demands further research.

Evaluation of Postoperative Care Protocol for Roux-en-Y Gastric Bypass Patients with Same-Day Discharge.

INTRODUCTION: Same-day discharge (SDD) after bariatric surgery is increasingly being performed and is safe with careful patient selection. However, detecting early complications during the first postoperative days can be challenging. We developed a postoperative care protocol for these patients and aimed to evaluate its effectiveness in detecting complications and monitoring patient recovery. METHODS: A single-center retrospective observational study was conducted with patients with who underwent Roux-en-Y Gastric Bypass (RYGB) with successful SDD. The study evaluated the effectiveness of the safety net that included simple remote monitoring with a pulsoximeter and thermometer, a phone consultation on postoperative day (POD) 1, and a physical consultation on POD 2-4. Furthermore, an analysis was performed on various factors including pain scores, painkiller usage, and incidences of nausea and vomiting on POD 1. RESULTS: In this study, 373 consecutive patients were included, of whom 19 (5.1%) were readmitted until POD 4. Among these, 12 patients (3.2%) reached out to the hospital themselves, while 7 (1.9%) were readmitted after phone or physical consultations. Ten of the readmitted patients had tachycardia. On POD 1, the mean numeric rating scale was 4 ± 2, and 96.6% of the patients used acetaminophen, 35.5% used naproxen, and 9.7% used oxynorm. Of the patients, 13.9% experienced nausea and 6.7% reported vomiting. CONCLUSION: A postoperative care protocol for SDD after RYGB, comprising simple remote monitoring along with a phone consultation on POD 1 and a physical checkup on POD 2-4, was effective in monitoring patient recovery and detecting all early complications.

Cardiac anomalies in children with congenital duodenal obstruction: a systematic review with meta-analysis.

BACKGROUND: Cardiac anomalies occur frequently in patients with congenital duodenal obstruction (DO). However, the exact occurrence and the type of associated anomalies remain unknown. Therefore, the aim of this systematic review is to aggregate the available literatures on cardiac anomalies in patients with DO. METHODS: In July 2022, a search was performed in PubMed and Embase.com. Studies describing cardiac anomalies in patients with congenital DO were considered eligible. Primary outcome was the pooled percentage of cardiac anomalies in patients with DO. Secondary outcomes were the pooled percentages of the types of cardiac anomalies, type of DO, and trisomy 21. A meta-analysis was performed to pool the reported data. RESULTS: In total, 99 publications met our eligibility data, representing 6725 patients. The pooled percentage of cardiac anomalies was 29% (95% CI 0.26-0.32). The most common cardiac anomalies were persistent foramen ovale 35% (95% CI 0.20-0.54), ventricular septal defect 33% (95% CI 0.24-0.43), and atrial septal defect 33% (95% CI 0.26-0.41). The most prevalent type of obstruction was type 3 (complete atresias), with a pooled percentage of 54% (95% CI 0.48-0.60). The pooled percentage of Trisomy 21 in patients with DO was 28% (95% CI 0.26-0.31). CONCLUSION: This review shows cardiac anomalies are found in one-third of the patients with DO regardless of the presence of trisomy 21. Therefore, we recommend that patients with DO should receive preoperative cardiac screening. LEVEL OF EVIDENCE: II.

Routine contrast enema prior to stoma reversal seems only required following treatment for necrotizing enterocolitis: An evaluation of the diagnostic accuracy of the contrast enema.

INTRODUCTION: Contrast enemas are often made prior to stoma reversal in order to detect distal intestinal strictures distal of the stoma. If untreated these strictures can cause obstruction which might necessitate redo-surgery. However, the value of contrast enemas is unclear. Therefore, we aim to evaluate the contrast enema's diagnostic accuracy in detecting strictures in children with a stoma. METHODS: Young children (≤3 years) treated with a stoma between 1998 and 2018 were retrospectively included. The STARD criteria were followed. Patients treated for anorectal malformations and those that died before stoma reversal were excluded. Surgical identification of strictures during reversal or redo-surgery within three months was used as gold standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC) reflected diagnostic accuracy. RESULTS: In 224 included children, strictures were found during reversal in 10% of which 95% in patients treated for necrotizing enterocolitis. Contrast enema was performed in 68% of all patients and detected 92% of the strictures. In the overall cohort, the sensitivity was 100%, specificity 98%, PPV 88% and NPV 100% whilst the AUC was 0.98. In patients treated for NEC, the sensitivity was 100%, specificity 97%, PPV 88% and NPV 100% whilst the AUC was 0.98. CONCLUSION: Strictures prior to stoma reversal seem to be mainly identified in patients treated for NEC and not in other diseases necessitating a stoma. Moreover, the contrast enema shows excellent diagnostic accuracy in detecting these strictures. For this reason we advise to only perform contrast enemas in patients treated for NEC. LEVEL OF EVIDENCE: II.

Systematic Review of Definitions and Outcome Measures for Postoperative Ileus and Return of Bowel Function after Abdominal Surgery in Children.

This review aims to objectify which definitions and outcome measures are used for the return of bowel function and postoperative ileus in children. PubMed and Embase were systematically searched from inception to December 17, 2020. Prospective studies conducted in children (aged 0-18 years) undergoing gastrointestinal surgery which reported on definitions and/or outcome measures for post-operative ileus or return of bowel function were evaluated. Definitions and outcome measures were extracted. From 4,027 references, 71 articles were included. From the 17 articles mentioning postoperative ileus, 8 (47%) provided a definition. In total, 34 outcome measures were used and 12 were unique. "Abdominal distension" was the most reported (41%) measure. In 41%, the outcome measures only described the return of gastric motility, while 18% described the return of intestinal motility. The return of bowel function was mentioned in 67 articles, none provided a definition. In total, 133 outcome measures were used and 37 were unique. Time to oral intake was the most reported (14%) measure. In 49%, the outcome measures only described the return of gastric motility, while 10% described the return of intestinal motility. High variation in definitions and outcome measures has limited the generalizability of research into postoperative bowel function in children. Without standardization, it will be impossible to compare research results and evaluate treatments. In children, the return of gastric motility seemingly should get more focus compared to adults. Therefore, we believe that a definition of postoperative ileus with an accompanying core outcome set, developed by a multidisciplinary team, specifically for children is required.

The Incidence of Associated Anomalies in Children with Congenital Duodenal Obstruction-A Retrospective Cohort Study of 112 Patients.

BACKGROUND: Duodenal obstruction (DO) is a congenital anomaly that is highly associated with other anomalies, such as cardiac anomalies and trisomy 21. However, an overview of additional anomalies and patient-specific risk factors for cardiac anomalies is lacking. Potential association with the vertebral, anorectal, cardiac, trachea-esophageal, renal and limb anomalies (VACTERL) spectrum remains unknown. Therefore, we aim to examine the incidence of associated anomalies, a VACTERL-spectrum association and patient-specific risk factors for cardiac anomalies in patients with DO. METHODS: A retrospective cohort study was performed between 1996 and 2021. Outcomes were the presence of any additional anomalies. Risk factors for cardiac anomalies were analyzed using multivariate logistic regression. RESULTS: Of 112 neonates with DO, 47% (N = 53/112) had one associated anomaly and 38% (N = 20/53) had multiple anomalies. Cardiac anomalies (N = 35/112) and trisomy 21 (N = 35/112) were present in 31%. In four patients, VACTERL-spectrum was discovered, all with cardiac anomalies. Trisomy 21 was found to be a risk factor for cardiac anomalies (OR:6.5; CI-95%2.6-16.1). CONCLUSION: Associated anomalies were present in half of patients with DO, of which cardiac anomalies and trisomy 21 occurred most often, and the VACTERL-spectrum was present in four patients. Trisomy 21 was a significant risk factor for cardiac anomalies. Therefore, we recommend a preoperative echocardiogram in patients with DO. In case a cardiac anomaly is found without trisomy 21, VACTERL-screening should be performed.

Adhesive small bowel obstruction following abdominal surgery in young children (≤ 3 years): A retrospective analysis of incidence and risk factors using multivariate cox regression.

BACKGROUND: Adhesions following abdominal surgery can cause small bowel obstruction (SBO) necessitating surgery. Whilst some studies have addressed SBO in children, the incidence of SBO, the diseases that are of increased risk as well as risk factors in young children remain unclear. Therefore, this study aims to determine; (1) the general incidence of SBO in young children, (2) which diseases entail highest incidence of SBO and (3) risk factors for SBO in young children. STUDY DESIGN: Young children (≤ 3 years of age) who underwent abdominal surgery in our tertiary referral centre between 1998-2018 were retrospectively included. Both general incidence and incidence per disease of SBO were determined. Independent risk factors for SBO were identified using cox-regression. RESULTS: The incidence of SBO was 5% (N = 88/1931) in our cohort. Five of the SBOs developed following laparoscopic treatment. Patients treated for gastroschisis (17%,N = 9/53), necrotizing enterocolitis (8%,N = 15/188) and intestinal atresia (7%,N = 13/177) were at high risk of experiencing SBO. Diaphragmatic hernia (28%,N = 7/25) and meconium ileus (28%,N = 7/25) also showed high SBO proportions. Having a history of stoma (HR:3.2, 95%-CI:2.0-5.2), undergoing emergency surgery (HR:2.2, 95%-CI:1.3-3.7) and postoperative infections (HR:1.9, 95%-CI:1.2-3.1) were general risk factors for the development of SBO. CONCLUSION: The incidence of SBO in young children seems higher than what has previously been reported in older children, which is why they should be studied separately. The incidence of SBO differs between diseases. Having a history of a stoma, emergency surgery and postoperative infections were independent risk factors for SBO development. Although less at risk, SBOs do develop after laparoscopies, which is why they should be included in more long-term follow-up studies. LEVEL OF EVIDENCE: II.

Treatment of jejunoileal atresia by primary anastomosis or enterostomy: Double the operations, double the risk of complications.

PURPOSE: No study has evaluated complication rates of the combined operations needed for temporary Enterostomy compared to primary anastomosis in the treatment of Jejunoileal Atresia. Therefore the aim of this study is: 1) to compare the occurrence of severe postoperative complications (defined as Clavien-Dindo ≥III within 30 days) and 2) to compare the occurrence of different short- and long-term complications following treatment for Jejunoileal atresia either by primary anastomosis or the combined Enterostomy procedures. METHODS: All consecutive neonates treated for Jejunoileal Atresias between January 1998 and February 2021 at our tertiary academic centres were retrospectively included. Perioperative characteristics and severity of postoperative complications (Clavien-Dindo) were extracted and evaluated, using chi-squared statistics, following each operation per treatment. RESULTS: Eighty patients were included of whom 48 (60%) received a primary anastomosis and 32 (40%) an Enterostomy. Perioperative baseline characteristics were comparable, apart from significantly more patients with a gastroschisis and significantly less patients with jejunum atresia in the Enterostomy group. Our results showed that 1) significantly (p ≤ 0.01) more CD ≥III occur following treatment by Enterostomy. 2) Both short-term (surgical site infection, wound dehiscence) and long-term (short bowel syndrome, adhesive bowel obstruction) complications occurred significantly more in those treated by Enterostomy. We showed no significant difference in anastomotic leakage/stenosis and mortality rates between both treatment strategies. CONCLUSION: Although perioperative factors might necessitate an Enterostomy, we advise a low threshold for performing a primary anastomosis when in doubt, taking into account the double risk of major complications found in patients treated with a temporary Enterostomy.

Major stoma related morbidity in young children following stoma formation and closure: A retrospective cohort study.

BACKGROUND: Little is known about stoma related morbidity in young children. Therefore, the aim of this study is to assess major morbidity after stoma formation and stoma closure and its associated risk factors. METHODS: All consecutive young children (age ≤ three years) who received a stoma between 1998 and 2018 at our tertiary referral center were retrospectively included. The incidence of major stoma related morbidity (Clavien-Dindo grade ≥III) was the primary outcome. This was separately analysed for stoma formation alone, stoma closure alone and all stoma interventions combined. Non-stoma related morbidity was excluded. Risk factors for major morbidity were identified using multivariable logistic regression analysis. RESULTS: In total 336 young children were included with a median follow-up of 6 (IQR:2-11) years. Of these young children, 5% (n = 17/336) received a jejunostomy, 57% (n = 192/336) an ileostomy, and 38% (n = 127/336) a colostomy. Following stoma formation, 27% (n = 92/336) of the young children experienced major stoma related morbidity, mainly consisting of high output stoma, prolapse and stoma stenosis. The major morbidity rate was 23% (n = 66/292) following stoma closure, most commonly comprising anastomotic leakage/stenosis, incisional hernia and adhesive obstructions. For combined stoma interventions, major stoma related morbidity was 39% (n = 130/336). Ileostomy was independently associated with a higher risk of developing major morbidity following stoma formation (OR:2.5; 95%-CI:1.3-4.7) as well as following closure (OR:2.7; 95%-CI:1.3-5.8). CONCLUSIONS: Major stoma related morbidity is a frequent and severe clinical problem in young children, both after stoma formation and closure. The risk of morbidity should be considered when deliberating a stoma.

Enteral Feeding Interventions in the Prevention of Necrotizing Enterocolitis: A Systematic Review of Experimental and Clinical Studies.

Necrotizing enterocolitis (NEC), which is characterized by severe intestinal inflammation and in advanced stages necrosis, is a gastrointestinal emergency in the neonate with high mortality and morbidity. Despite advancing medical care, effective prevention strategies remain sparse. Factors contributing to the complex pathogenesis of NEC include immaturity of the intestinal immune defense, barrier function, motility and local circulatory regulation and abnormal microbial colonization. Interestingly, enteral feeding is regarded as an important modifiable factor influencing NEC pathogenesis. Moreover, breast milk, which forms the currently most effective prevention strategy, contains many bioactive components that are known to support neonatal immune development and promote healthy gut colonization. This systematic review describes the effect of different enteral feeding interventions on the prevention of NEC incidence and severity and the effect on pathophysiological mechanisms of NEC, in both experimental NEC models and clinical NEC. Besides, pathophysiological mechanisms involved in human NEC development are briefly described to give context for the findings of altered pathophysiological mechanisms of NEC by enteral feeding interventions.

Accuracy of ultrasonography for differentiating between simple and complex appendicitis in children.

PURPOSE: Accurate differentiation between simple and complex appendicitis is important since differences in treatment exist. This study aimed to assess the accuracy of ultrasonography in differentiating between simple and complex appendicitis. METHODS: Data from children aged < 18 years who underwent appendectomy between the 1st of January 2013 and the 1st of January 2018 were analyzed retrospectively. Ultrasonography reports of eligible children were divided into simple (test negative) and complex appendicitis (test positive) based on predefined criteria and compared to a gold standard (a combination of predefined perioperative and histopathological criteria). Sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) were calculated to measure ultrasonographic accuracy in differentiating between simple and complex appendicitis. RESULTS: 176 children were eligible for inclusion. The mean age at the time of operation was 10.1 ± SD 4.6 years. 84 (47.7%) children had simple appendicitis and 92 (52.3%) had complex appendicitis. The use of ultrasonography yielded a sensitivity: 46%, specificity: 90%, PPV: 84%, and NPV: 60%. CONCLUSION: Ultrasonography as standalone modality is not suitable for differentiating between simple and complex appendicitis in children. To improve preoperative differentiation, other variables such as clinical signs and laboratory data are necessary in conjunction with ultrasonography findings.

Incisional hernia after abdominal surgery in infants: A retrospective analysis of incidence and risk factors.

PURPOSE: Incisional hernia (IH) is a complication following abdominal surgery extensively studied in adults but less so in infants. This study aimed to identify the incidence, high risk diseases and risk factors of IH following abdominal surgery in infants. METHODS: Infants undergoing abdominal surgery before the age of three years in our tertiary centre between 1998 and 2018 were included. Patient demographics, peri­operative details and the course during follow up were retrospectively extracted from patient records. Multivariate logistic regression was performed to identify risk factors. RESULTS: The incidence of incisional hernia was 5.2% (107/2055). Necrotizing enterocolitis (12%), gastroschisis (19%), and omphalocele (17%) had the highest incidences of IH. Wound infection (OR: 5.3, 95%-CI:2.9-9.5), preterm birth (OR: 4.2, 95%-CI:2.6-6.7) and history of stoma (OR 1.7, 95%-CI:1.1-2.8) were significant risk factors for IH. Whilst age at surgery, surgical approach and total number of operations did not significantly influence IH development. The IH resolved in 15% (16/107) without surgery. CONCLUSION: One in twenty infants experiences IH following abdominal surgery, which is higher than previously described. Understanding the incidence of IH and associated risk factors will allow physicians to identify infants that may be at increased risk for IH and to possibly act pre-emptively.

The incidence of abdominal surgical site infections after abdominal birth defects surgery in infants: A systematic review with meta-analysis.

BACKGROUND: Surgical site infections (SSI) are a frequent and significant problem understudied in infants operated for abdominal birth defects. Different forms of SSIs exist, namely wound infection, wound dehiscence, anastomotic leakage, post-operative peritonitis and fistula development. These complications can extend hospital stay, surge medical costs and increase mortality. If the incidence was known, it would provide context for clinical decision making and aid future research. Therefore, this review aims to aggregate the available literature on the incidence of different SSIs forms in infants who needed surgery for abdominal birth defects. METHOD: The electronic databases Pubmed, EMBASE, and Cochrane library were searched in February 2020. Studies describing infectious complications in infants (under three years of age) were considered eligible. Primary outcome was the incidence of SSIs in infants. SSIs were categorized in wound infection, wound dehiscence, anastomotic leakage, postoperative peritonitis, and fistula development. Secondary outcome was the incidence of different forms of SSIs depending on the type of birth defect. Meta-analysis was performed pooling reported incidences in total and per birth defect separately. RESULTS: 154 studies, representing 11,786 patients were included. The overall pooled percentage of wound infections after abdominal birth defect surgery was 6% (95%-CI:0.05-0.07) ranging from 1% (95% CI:0.00-0.05) for choledochal cyst surgery to 10% (95%-CI:0.06-0.15) after gastroschisis surgery. Wound dehiscence occurred in 4% (95%-CI:0.03-0.07) of the infants, ranging from 1% (95%-CI:0.00-0.03) after surgery for duodenal obstruction to 6% (95%-CI:0.04-0.08) after surgery for gastroschisis. Anastomotic leakage had an overall pooled percentage of 3% (95%-CI:0.02-0.05), ranging from 1% (95%-CI:0.00-0.04) after surgery for duodenal obstruction to 14% (95% CI:0.06-0.27) after colon atresia surgery. Postoperative peritonitis and fistula development could not be specified per birth defect and had an overall pooled percentage of 3% (95%-CI:0.01-0.09) and 2% (95%-CI:0.01-0.04). CONCLUSIONS: This review has systematically shown that SSIs are common after correction for abdominal birth defects and that the distribution of SSI differs between birth defects.

The incidence of different forms of ileus following surgery for abdominal birth defects in infants: a systematic review with a meta-analysis method.

Objectives: Ileus following surgery can arise in different forms namely as paralytic ileus, adhesive small bowel obstruction or as anastomotic stenosis. The incidences of these different forms of ileus are not well known after abdominal birth defect surgery in infants. Therefore, this review aims to estimate the incidence in general between abdominal birth defects. Content: Studies reporting on paralytic ileus, adhesive small bowel obstruction or anastomotic stenosis were considered eligible. PubMed and Embase were searched and risk of bias was assessed. Primary outcome was the incidence of complications. A meta-analysis was performed to pool the reported incidences in total and per birth defect separately. Summary: This study represents a total of 11,617 patients described in 152 studies of which 86 (56%) had a follow-up of at least half a year. Pooled proportions were calculated as follows; paralytic ileus: 0.07 (95%-CI, 0.05-0.11; I 2=71%, p≤0.01) ranging from 0.14 (95% CI: 0.08-0.23) in gastroschisis to 0.05 (95%-CI: 0.02-0.13) in omphalocele. Adhesive small bowel obstruction: 0.06 (95%-CI: 0.05-0.07; I 2=74%, p≤0.01) ranging from 0.11 (95% CI: 0.06-0.19) in malrotation to 0.03 (95% CI: 0.02-0.06) in anorectal malformations. Anastomotic stenosis after a month 0.04 (95%-CI: 0.03-0.06; I 2=59%, p=0.30) ranging from 0.08 (95% CI: 0.04-0.14) in gastroschisis to 0.02 (95% CI: 0.01-0.04) in duodenal obstruction. Anastomotic stenosis within a month 0.03 (95%-CI 0.01-0.10; I 2=81%, p=0.02) was reviewed without separate analysis per birth defect. Outlook: This review is the first to aggregate the known literature in order approximate the incidence of different forms of ileus for different abdominal birth defects. We showed these complications are common and the distribution varies between birth defects. Knowing which birth defects are most at risk can aid clinicians in taking prompt action, such as nasogastric tube placement, when an ileus is suspected. Future research should focus on the identification of risk factors and preventative measures. The incidences provided by this review can be used in those studies as a starting point for sample size calculations.

Incisional hernia after surgical correction of abdominal congenital anomalies in infants: a systematic review with meta-analysis.

Incisional hernia (IH) in children could result in life-threatening complications, including incarceration and bowel strangulation. The incidence and risk factors of IH in infants are scarcely reported. Since IH-correction may require extensive surgery and a long recovery program, identifying infants and birth defects at risk, may lead to a different approach during the primary surgery. Therefore, the aim of this review is to systematically review the available data on the incidence of IH following surgery for congenital anomalies in infants. All studies describing IH were considered eligible. PubMed and Embase were searched and risk of bias was assessed. Primary outcome was the incidence of IH, secondary outcomes were difference in IH occurrence between disease severity (complex vs simple) and closure method (SILO vs primary closure) in gastroschisis patients. A meta-analysis was performed to pool the reported incidences in total and per congenital anomaly separately. Subgroup analysis within gastroschisis articles was performed. The 50 included studies represent 3140 patients. The pooled proportion of IH was 0.03 (95% CI 0.02-0.05; I2 = 79%, p ≤ 0.01) all anomalies combined. Gastroschisis (GS) reported highest pooled proportion 0.10 (95% CI 0.06-0.17; n = 142/1273; I2 = 86%; p ≤ 0.01). SILO closure (OR 3.09) and simple gastroschisis, i.e. without additional anomalies, (OR 0.18) were of significant influence. This review reports the incidence of IH in infants with different congenital abdominal anomalies, of which gastroschisis reported the highest risk. In GS patients, complex GS and SILO closure are risk factors for IH development.