Protective Effects of Bronchopulmonary Sequestration (BPS) on the Prognosis of Neonates with Congenital Diaphragmatic Hernia (CDH)

Abstract

Background

Congenital diaphragmatic hernia (CDH) and bronchopulmonary sequestration (BPS) are rare congenital anomalies that can coexist, with studies suggesting that 25–40% of CDH cases are accompanied by BPS. The association between CDH and BPS is thought to arise from embryological disruptions during early gestation, with BPS potentially serving as an anatomical barrier. This study aimed to evaluate the incidence, clinical characteristics, and outcomes of patients with concurrent CDH and BPS at a single institution to improve therapeutic approaches.

Methods

This study retrospectively analyzed the medical records of neonates diagnosed and treated for BPS concurrent with CDH at Asan Medical Center from 1990 to 2021, identifying 15 cases (3.0%) among 493 CDH patients. Comprehensive data on demographics, treatments, outcomes, diagnostic imaging, and pathological findings were collected and analyzed to explore disease characteristics and evaluate clinical outcomes.

Results

This study analyzed 15 neonates with concurrent BPS and CDH, with a male predominance (10:5) and an average gestational age of 37.8 weeks, of whom 80% were diagnosed prenatally. CDH repair was performed at a median of 8 days, with no acute repair-related complications observed. In some cases, additional procedures such as hiatal hernia or re-do CDH repair was required, and BPS resection was performed either simultaneous or delayed. Follow-up revealed that most patients grew within the 50th percentile range, with thoracoscopic approaches feasible in over half of the cases, and recurrence-free outcomes achieved in those treated for hiatal hernia or BPS.

Discussions

No statistical difference in CDH severity was observed between the CDH and CDH + BPS groups, and the clinical outcome of CDH + BPS was better, although the high prevalence of sac-associated CDH types may have confounded the results. Our findings provide additional evidence supporting the protective effect of BPS. However, they also highlight the need for further studies in larger populations to clarify the causal relationship.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-025-05755-w.

Introduction

Congenital diaphragmatic hernia (CDH) is a rare condition identified in approximately 1 in 2,500 live births, and associated with high morbidity and mortality rates [1]. Bronchopulmonary sequestration (BPS), another rare congenital abnormality, is defined by the development of non-functional pulmonary mass disconnected from the normal tracheobronchial tree [2]. Studies based on prenatal ultrasonography and postmortem analysis have identified BPS in 0.15–1.8% of neonatal populations. Numerous case reports have indicated a strong association between CDH and BPS, with studies variable reporting that extralobar coexisting BPS could be identified in 30–40% of CDH cases, and that 25% of CDH cases (16/64) were accompanied by BPS [3].

One embryological theory explaining this association proposes that BPS, which arises during the fourth to fifth weeks of gestation, disrupts diaphragm formation by the 10 th week, leading to incomplete closure of the pleuroperitoneal canal [2]. Sequestration may act as an anatomical barrier during diaphragmatic development, exacerbating hernia formation. The prognoses of these dual anomalies can vary. Although BPS exerts minimal impact on survival, CDH remains a major determinant of mortality [1]. Two contrasting outcomes are commonly observed. In some cases, sequestration serves as an anatomical barrier, preventing the herniation of abdominal contents and promoting lung growth [4, 5], while in others, it contributes to a ‘liver-up condition’ that decreases the lung-to-head ratio (LHR), consequently worsening mortality [6].

Given the low prevalence of these anomalies, the factors influencing patient survival have not been extensively studied. Thus far, reduced LHR has been identified as the only negative prognostic factor [3]. Understanding the clinical course and prognostic factors in these patients is crucial for improving therapeutic approaches. Therefore, the study aimed to evaluate the incidence, clinical characteristics, and outcomes of patients diagnosed with CDH or BPS at a single institution.

Methods

Study participants and variables of interest

This study comprised a retrospective review of the medical records of a single institution, enrolling neonates diagnosed with and treated for CDH (with or without BPS) at Asan Medical Center, Seoul, between January 1990 and December 2021. The exclusion criteria included cases lost to follow-up at our institution or those confirmed as other disease, such as eventration after surgery. Among the 493 neonates diagnosed with CDH during the study period, 15 (3.0%) had concurrent BPS (CDH + BPS). Data related to demographics, treatments, and outcomes of CDH were collected through a comprehensive review of the medical records. Additionally, diagnostic imaging and pathological findings of BPS were analyzed to better understand the relationship between CDH and BPS. Follow-up data and clinical results were documented to evaluate the clinical outcomes. To compare the CDH concurrent with BPS to control group, data from the CDH group were extracted from our institution's CDH database. The control group consisted of data collected between 2008 and 2020, excluding patients with incomplete data (n = 235). Among them, 221 CDH patients (94.4%), whose CDH type was clearly documented in the surgical records, were included in the group comparison. The Congenital Diaphragmatic Hernia Study Group (CDHSG) is an international consortium of medical centers that actively collect and voluntarily contribute data on live-born congenital diaphragmatic hernia (CDH) patients [7]. Established in 1995, the group has compiled a comprehensive registry encompassing data from over 14,000 patients, enabling the investigation of various clinical questions and the promotion of standardized treatment protocols for CDH. ​In one of their significant studies, CDHSG reported on the clinical outcomes of 72 CDH patients with associated bronchopulmonary sequestration (BPS), marking it as the largest study of its kind. ​We have cited the relevant literature to compare our study's results with those findings [6].

Statistical analyses

All statistical analyses were performed using R software (version 4.2.3; R Core Team, Vienna, Austria). The mean was calculated after testing data normality using the Shaprio-Wilks test, and an appropriate mean or median value was derived based on the results. Chi-square tests were used to compare difference between the CDH and CDH + BPS groups. Statistical significance was set at p < 0.05.

Ethics

The study protocol was approved by the Institutional Review Board of Asan Medical Center (IRB No.: 2022–0445). The requirement for informed consent was waived after the information was deidentified. This study was conducted in accordance with the principles of the Declaration of Helsinki.

Results

The data of the 15 neonates with concurrent BPS or CPAM and CDH (CDH + BPS or CPAM) are summarized in Supplement Table 1. The male-to-female ratio was 10:5, indicating a male predominance. The average gestational age (GA) was 37.8 weeks and 2.7 days, with most neonates being full-term, with appropriate birth weights for their gestational age. A prenatal diagnosis of BPS and CDH was made in 12 patients (80.0%). The mean 1-min Apgar score (AS1) was 7, with improvement at 5 min (AS5). The ratio of vaginal delivery to cesarean section (C-section) was 8:7, indicating a near even split.

In our study, we used patients with CDH treated in our center between 2008 and 2020 as a control group, due to incomplete construction of the database for the entire CDH cohort. Compared to the CDHSG outcomes, our CDH + BPS cohort showed a male-dominant trend (male-to-female ratio: 2 vs. 1.2) and a similar prenatal diagnosis rate (80.0% vs. 86.1%) [6]. Cardiac anomalies were present in 13.3% of our cohort compared with 11.1% in the CDHSG group. Except for the sex ratio, the basic characteristics of the study patients were similar between the two study cohorts. In our isolated CDH cohort, the distribution of CDH types was as follows: A (5.1%), B (70.2%), C (13.2%), and D (5.5%). Among the 15 patients with CDH and concurrent BPS or CPAM, the distribution of types—A (6.7%), B (60.0%), C (26.7%), and D (6.7%)—showed no statistically significant difference compared to the overall cohort (χ² test, p = 0.577; Table 1). Hernial sacs were observed in 60.6% of patients with CDH + BPS, which was higher than the 32.4% reported in the CDHSG group. Mortality associated with CDH + BPS was not observed, as deaths were directly attributed to irreversible cardiac failure following cardiac anomaly correction. The reduced mortality rate observed in our cohort compared to the CDHSG database may reflect the advanced expertise of our center, which manages more than half of CDH patients in South Korea.

Table 1.

Comparison of characteristics between CDH patients with BPS or CPAM (CDH + BPS/CPAM) and their control (isolated CDH)

(a) Comparison between CDH + BPS/CPAM and isolated CDH
	CDH + BPS/CPAM (n = 15)	CDH (n = 221/235)	p-value
Type A	1 (6.7%)	12 (5.1%)	0.577
Type B	9 (60.6%)	165 (70.2%)
Type C	4 (26.7%)	31 (13.2%)
Type D	1 (6.7%)	13 (5.5%)
(b) Comparison between CDH with pathologically proven BPS and isolated CDH
	CDH + BPS (n = 11)	CDH (n = 221/235)	p-value
Type A	1 (9.1%)	12 (5.1%)	0.73
Type B	7 (63.7%)	165 (70.2%)
Type C	2 (18.2%)	31 (13.2%)
Type D	1 (9.1%)	13 (5.5%)

^*CDH + BPS/CPAM CDH concurrent with BPS or CPAM, CDH Congenital diaphragmatic hernia, BPS Bronchopulmonary sequestration, CPAM Congenital pulmonary airway malformation

The mean abdomen-to-chest circumference (A/C) ratio was 0.9 ± 0.1, suggesting a scaphoid abdomen, in which the abdominal circumference was smaller than the chest circumference. Cardiac anomalies that did not inotropic support were identified in two neonates. Among the three neonates requiring inotropic support (patients 7, 9, and 13), all were diagnosed with CDH type B or C, characterized by relatively larger defects or severe organ herniation (Supplement Table 2). Ventilation support was not associated with sac type, size, or presence. The median age at CDH repair was 8.0 days (IQR: 4.0–27.0 days, Supplement Table 3). Patch repair was performed in three neonates; in one case, the abdominal wall could not be closed, necessitating a second-stage operation for abdominal wall closure (Supplement Table 3).

Feeding was initiated on postoperative day 3.0 (IQR: 2.5–8.0 days), and patients were discharged on postoperative day 14.0 (IQR: 9.0–10.0 days). No acute CDH repair-related complications were observed. Hiatal hernia was diagnosed in two cases postoperatively, on days 587 (patient 7) and 154 (patient 10), requiring hiatal hernia repair (Fig. 1). Both patients were Type B with a sac, and underwent thoracoscopic repair without patch placement; medial-sided hiatal laxity of the esophagus was noted in both cases. Fundoplication was performed in Patient 7, whereas Patient 10 underwent only hiatal hernia repair. Both patients remained recurrence-free postoperatively.

Fig. 1.

Surgical images of two patients (Patients 7 and 10) with hiatal hernial progression following CDH repair (a), (b): Patient 7 underwent thoracoscopic repair for Type B CDH with sac. Hiatal hernia was diagnosed 587 days postoperatively, accompanied by severe reflux symptoms; laparoscopic hiatal hernia repair was planned accordingly. Due to the large hernial defect, open conversion was performed along with fundoplication. The patient has remained symptom-free since the surgery. a Shows an image taken immediately after CDH repair, and (b) demonstrates the hernial defect. c, d: Patient 10 underwent thoracoscopic repair for Type B CDH with sac. (c) Shows the CDH lesion with the sac before repair, and (d) illustrates the defect in the hiatus observed during laparoscopic hiatal hernia repair. In the present case, the defect was closed and fixed, leading to resolution of reflux symptoms without recurrence. CDH: congenital diaphragmatic hernia

BPS was identified on the same side as that of the CDH, with varying sizes (Table 2). The two CPAM cases in our cohort were confirmed through resection and histopathological analyses. In one case, despite patient growth, the lesion size remained stable, requiring resection. The patient recovered well after surgery. These two neonates were still under follow-up with imaging studies at the time of writing, showing good growth without the need for urgent surgery (Fig. 2). Among the 12 neonates who underwent BPS resection, eight underwent simultaneous resection during CDH repair, while four underwent delayed resection. One patient (patient 12) showed asymptomatic focal recurrence on follow-up CT, resulting in re-operation and re-resection. Thoracoscopic approaches were feasible in seven cases. Pathological examination revealed congenital pulmonary airway malformation (CPAM) in two patients, a hybrid lesion of CPAM and BPS in one patient, and BPS in the remaining cases (Fig. 3). In two patients, fetal sonography follow-up reports clearly documented that initially undetectable CDH was ultimately diagnosed as the size of the sequestration decreased.

Table 2.

Description of CDH patients with BPS or CPAM: disease extent, treatment, and outcomes

Patient No	Location	Size (cm*cm*cm)	Age at operation (days)	Approach	Chest tube insertion	Chest tube removal (days)	Time to discharge (days)	Pathology	Complications
1	LLL	5 × 2.5x 2	14	OA	N		14	Pulmonary sequestration
2	LLL	3.6 × 2.6x 1.2	75	OT	Y	4	6	Extralobar pulmonary sequestration
3	LLL	3 × 3x 2	5125	T	Y	2	8	Extralobar pulmonary sequestration
4	LLL	0.9 × 2.5x3.2
5	LLL	5.0 × 3.0 × 3.0	327	T	N		4	Pulmonary sequestration extralobar type
6	LLL	3.5 × 2.2 × 1.1	407	OT	Y	2	37	Pulmonary sequestration, extralobar type	Atelectasis
7	LLL	4.3 × 1.7 × 1	6	T	Y	5	17	Pulmonary sequestration, intralobar type
8	LLL	2.5 × 1.5 × 0.8	8	T	Y	4	12	Pulmonary sequestration extralobar type
9	LLL	1 × 0.9 × 0.5	8	OA	Y	18	44	Pulmonary sequestration, extralobar type
10	LLL	5 × 3 × 0.8	2	T	Y	7	10	Clinically pulmonary sequestration fragments of lung tissue in alveolar stage
11	LLL	3.5 × 2.5 × 2	3	OA	Y	22	30	Pulmonary sequestration, extralobular type
12	RLL	3.2 × 3.1x2.8	334	T	Y	5	10	Pulmonary sequestration, extralobar type
13	LLL	1.1 × 3.0
14	RLL	7 × 4 × 2	674	T	Y	26	27	Congenital pulmonary airway malformation, type 2	Air leak
15	RLL	2 × 2 × 0.5	676	T	N		6	Congenital pulmonary airway malformation
	R:L = 3:12			OA:OT:T = 3:2:7		5.0 (4.0–18.0)
pBPS	R:L = 1:10			OA:OT:T = 3:2:6		5.0 (2.0–7.0)

^*BPS bronchopulmonary sequestration, CPAM Congenital pulmonary airway malformation, LLL Left lower lobe, RLL Right lower lobe, OA Open abdominal approach, OT Open thoracotomy, T Thoracoscopic approach, NA Not available, HFO High-frequency oscillation, pBPS pathologically-confirmed BPS

Fig. 2.

Imaging findings of two patients (Patients 4 and 13) who underwent imaging follow-up without resection In the most recent chest CT scan of patient 4 (a 13-year-old boy), the previously observed left juxtadiaphragmatic extralobar pulmonary sequestration was smaller than before (a, arrow). The feeding artery supplied by the celiac trunk showed no noticeable changes compared with the previous scan. b, arrow) Follow-up CT scan of a 3-year-old boy showing a partially expanded sequestered lung in the left lower hemithorax (c, arrow). The hyperlucent expanded area indicates the presence of a CPAM and a hybrid lesion, revealing the characteristics of an interlobar-type pulmonary sequestration supplied by the celiac axis, and drained by the inferior pulmonary vein (Patient 13). The soft tissue in the infradiaphragmatic area previously observed on ultrasonography before surgery is now thought to represent sequestration near the heart in the supradiaphragmatic area (d, asterisk). *CT: computed tomography; CPAM: congenital pulmonary airway malformation

Fig. 3.

Representative pictures of a patient with CPAM concurrent with CDH (Patient 14) (a) On a CT scan performed at 293 days of age, the suspected CPAM lesion measured 42.2 × 34.7 mm; at this point, the patient was healthy and asymptomatic, without respiratory distress. b On a CT scan performed at 639 days of age, the suspected CPAM lesion measured 50.0 × 38.5 mm, showing no significant size change. As the patient remained stable and asymptomatic, surgery was performed at 674 days of age. c Gross pathology of the specimen. Pathologic findings were consistent with anomalous cystic lung, confirmed as congenital pulmonary airway malformation (CPAM), type 2. d The final follow-up chest X-ray showed no abnormalities. The patient has been doing well postoperatively, without any evidence of complications or pulmonary dysfunction. *CT: computed tomography; CPAM: congenital pulmonary airway malformation

The follow-up period had a median duration of 740.0 days (IQR: 204.0–2952.0 days, Table 3). One neonate (Patient 6) died during postoperative care following cardiac surgery. The Z-score for weight was 0.1 (IQR: −1.0–0.3), indicating that most patients ultimately grew within the 50 th percentile range of the growth curve.

Table 3.

Clinical outcomes of patients

Patient No	Last follow-up (days)	Survival	Body weight (kg)	Body weight (Z-score)	Height (Z-score)	BMI (Z-score)	Clinical characteristics
1	4489	Y	41	−0.5	−2.38	0.85	At fetal sonography, hernia was confirmed with a decrease in the size of the sequestration
2	4907	Y	53.76	0.05	0.03	0.01
3	727	Y	11.8	−0.11	−0.25
4	4048	Y	56.1	1.65	0.47	1.99	Left jusxtadiaphragmatic extralobar pulmonary sequestration: chest CT follow-up
5	2400	Y	25.1	0.68	0.26	0.7
6	79	N (Cardiac problem)	2.48	−6.03	−6.22
7	2910	Y	27.8	0.13	0.19	0.12	At fetal sonography, hernia was confirmed with a decrease in the size of the sequestration
8	2581	Y	24.05	0.18	1.04	−0.58
9	43	Y	2.642	−3.23	−2.65
10	187	Y	6.6	−1.66	−0.76
11	478	Y	9.1	−1.13	0.5
12	217	Y	8	0.37	0.35
13	191	Y	8.5	0.63	−0.85		It is thought that the feeding vessel of the sequestration runs across the diaphragm from the aorta and that the hernia repair will not be affected when the sequestration is returned to the ventral side. Therefore, herniorrhaphy is performed after pull down the sequestration to abdomen after planning an imaging follow-up for sequestration
14	740	Y	11.6	0.09	0.24	−0.14
15	2994	Y	24.6	−0.86	−0.45	−0.91
	740.0 (204.0–2952.0)		11.7 (8.0–27.8)	0.1 (−1.0–0.3)	0.0 (−0.8–0.3)	0.3 ± 0.9
pBPS	727.0 (202.0–2745.5)		11.8 (7.3–26.5)	−0.11 (−1.395–0.155)	0.03 (−1.57–0.31)	0.22 ± 0.5

^*pBPS pathologically-confirmed BPS

Discussion

BPS is a form of bronchopulmonary malformation in which non-functional lung tissue, disconnected from the normal bronchial system, receives blood from the systemic circulation [6, 8]. BPS is classified into intralobar and extralobar types, with the majority of cases occurring in the lower left lobe [8]. BPS is believed to develop at approximately 4–5 weeks of gestation, contributing to the progression of CDH by interfering with diaphragm fusion and pleuroperitoneal canal closure at around 10 weeks of gestation. Consequently, the extralobar type is more commonly associated with CDH. Our results show a trend similar to that of previous findings.

CPAM is a hamartomatous lesion of the lung classified based on the size of the cyst and the mucosal lining [9]. These two conditions may coexist, and have also been reported to be associated with CDH [6, 10–13]. The incidence of simultaneous CDH and BPS remains poorly understood owing to limited reports [2, 4, 8, 14–17]. In one large-scale retrospective study based on the CDHSG database, Coughlin et al. estimated the likelihood of co-occurrence as approximately 3.4% (72/2118) [6]. This aligns more closely with real-world data compared to previously reported prevalences of 1.2% to 30% in smaller series and case reports. In our retrospective cohort study, the incidence was similar, at 3.0% (15/493).

There have also been a few reports of cases in which CPAM and CDH coexist. For example, in 2012, Herman & Siegel reported a case in which prenatal diagnosis was followed by surgical treatment [9]. When CDH and BPS occur simultaneously, the clinical course of CDH becomes more complex. However, the prognosis of patients with CDH has been reported to improve when BPS is present [5]. Hypotheses to explain this have alternately postulated that additional lung tissue from BPS may compensate for the hypoplasia caused by CDH, changes in blood flow due to BPS may positively affect pulmonary circulation, and that the interaction between CDH and BPS may mitigate the severity of each condition. However, other reports have suggested that BPS itself does not significantly affect the clinical course of CDH [18], while a 2008 study by Grethel et al. reached a skeptical conclusion regarding the anatomical protective effects of BPS [3]. Among the 14 patients with CDH + BPS (out of 110) in this latter, 13 had liver herniation, of whom eight had a lung-to-head ratio (LHR) < 1.0, predictive of poor prognosis. Only six patients survived, suggesting the limitations of the protective hypothesis.

In contrast, Coughlin et al. provided more robust demographic data through a large-scale comparative analysis [6]. They reported a higher prevalence of CDH type C in patients with CDH + BPS than in patients with isolated CDH. Additionally, a higher proportion of patients with CDH + BPS underwent patch repair, with significantly higher extracorporeal membrane oxygenation use and mortality, presenting conclusions that differ from standard assumptions.

BPS is traditionally treated with surgical resection [19, 20]. Extralobar BPS allows resection without damaging the normal lung tissue, whereas intralobar BPS typically requires lobectomy [21]. Recently, embolization has been reported as a successful alternative treatment modality in children, with interventions using coils also proving effective in adults [21–23]. Among neonates, umbilical artery embolization of the BPS vessels has also shown promising results [23]. Nevertheless, treatment may not be required if the BPS lesion decreases in size before birth and is not associated with complications, such as fetal hydrops or pleural effusion [21, 24]. Prognosis is generally favorable, with > 75% of antenatally diagnosed BPS cases showing regression or size reduction. CT follow-up after an average of six months revealed significant regression in 17 patients (70.8%) and complete resolution in two cases (8.3%) [21].

Among the patients who underwent simultaneous CDH repair and BPS resection, five underwent surgery using a thoracoscopic approach, including three neonates within 10 days of birth. The relatively high proportion of patients eligible for the thoracoscopic approach indirectly indicates that the clinical outcomes of these patients were favorable relative to the defect size, suggesting that the feasibility of attempting a thoracoscopic approach may be higher in patients with fewer herniated organs and adequately developed abdominal cavities, where BPS may have acted as a plug providing a protective effect against herniation before birth. Additionally, from a technical perspective, Yamada et al. reported that simultaneous correction using a thoracoscopic approach is feasible in neonates [25].

Six patients underwent CDH repair without a concurrent BPS resection. Of these, three (patients 3, 6, and 24) required additional resection due to non-regressing BPS. In another case, BPS resection coincided with re-do CDH repair because of a focal recurrence. However, during the follow-up period after CDH repair and BPS resection, none of the patients exhibited any BPS-related symptoms. The two patients who did not undergo BPS resection remained asymptomatic with a stable lesion size and were followed-up with periodic imaging.

CPAM is a distinct condition from BPS in terms of histogenesis and blood supply. However, considering the location, characteristics, and size of the lesions in the patients included in this study, as well as their association with CDH, we presumed that CPAM could have a similar impact on the clinical course of CDH patients. Therefore, it was included in the analysis. In addition, we have provided supplementary table results excluding CPAM and histologically undiagnosed BPS.

Additionally, we conducted an analysis of the pathologically confirmed BPS (pBPS) group, and the results are presented in the last row of the table. When comparing only the pBPS infants with those with isolated CDH, there was no statistically significant difference in the distribution of lesion types (Table 1(b)). The clinical characteristics, clinical course, and trends in the surgical treatment of CDH, as shown in Supplementary Tables 1–3, also did not differ significantly. Among the four excluded patients, three underwent repair via a thoracoscopic approach, suggesting that the CPAM patients and BPS patients who did not undergo surgical resection were clinically stable enough to undergo a one-stage thoracoscopic reduction, despite being classified as type B or C. The size of the BPS lesions and the associated clinical course also did not demonstrate notable differences in overall trends (Table 2– 3).

This study has several limitations which should be considered, largely stemming from its single-center, retrospective design. However, our center deals with 35.5–61.5% of CDH patients born in South Korea, reflecting the characteristics of the national CDH patient population [26]. The nature of referral centers may introduce bias, as prenatally undiagnosed cases referred after birth are likely to be more severe. Overall, included data from 235 patients with CDH treated at our center between 2008 and 2020 as a comparison group to overcome the limitations of this case series. The consistent annual number of patients with CDH (16–29 patients per year) managed at our center supported the homogeneity of the study population. Furthermore, a high proportion of patients with CDH + BPS in this cohort had a sac. Since the presence of a sac is considered a favorable prognostic factor for CDH [27], it could confound the evaluation of BPS's impact of BPS on prognosis. However, the small cohort size of 15 patients limited our ability to assess this association.

The primary significance of our study lies in the provision of comprehensive evidence on the clinical course of patients with CDH + BPS. Overall, we demonstrated that there was no statistically significant difference in the size of the hernia defect (CDH type) between these patients and the overall cohort. Further, in contrast to the findings of two previous reports, we confirmed favorable clinical outcomes relative to disease severity. We also hypothesize that BPS may act as a plug, facilitating lung growth and maintaining the abdominal organs in place, thereby contributing to favorable clinical outcomes relative to the defect size. However, the high prevalence of the sac-associated CDH types in our cohort complicates the attribution of these findings to the protective effects of BPS. Further large-scale studies are required to explore this interaction, along with broader analyses across diverse populations in order to establish generalized conclusions.

Conclusion

The present study is significant as it provides evidence supporting the traditional theory of the effect of BPS on CDH. As various research findings have been presented across diverse populations, we anticipate more studies to gain a more accurate understanding of the impact of BPS on CDH.

Abbreviations

CDH

Congenital diaphragmatic hernia

BPS

Bronchopulmonary sequestration

CPAM

Congenital pulmonary airway malformation.

CDH + BPS/CPAM

CDH concurrent with BPS or CPAM

AS

Apgar score

A/C ratio

Abdomen-to-Chest Circumferential Ratio

Authors’ contributions

SG designed and NK supervised the study. SG collected and collected all clinical information of the patients. JN and YK reviewed clinical information of the patients. SG wrote the original draft manuscript. All authors discussed the results and commented on the manuscript.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability

The datasets generated during and/or analyzed during the current study are not publicly available but are available from the corresponding authors at reasonable request.

Declarations

Ethics approval and consent to participate

The study protocol was approved by the Institutional Review Board of Asan Medical Center (IRB No.: 2022–0445). The requirement for informed consent was waived after the information was deidentified. This study was conducted in accordance with the principles of the Declaration of Helsinki.

Consent for publication

Not applicable. As this is a retrospective study, informed consent for publication was waived. No identifiable images or clinical details that could potentially identify individual patients are included in this manuscript.

Competing interests

The authors declare no competing interests.