Surgical perspectives regarding application of biomaterials for the management of large congenital diaphragmatic hernia defects

Surgical management of the diaphragmatic defect in congenital diaphragmatic hernia: a contemporary review

Worldwide, 150 children are born each day with congenital diaphragmatic hernia (CDH), a diaphragmatic defect with concomitant abnormal lung development. Patients with CDH with large defects are particularly challenging to treat, have the highest mortality, and are at significant risk of long-term complications. Advances in prenatal and neonatal treatments have improved survival in high-risk patients with CDH, but surgical treatment of large defects lacks standardization. Open repair by an abdominal approach has long been considered the traditional procedure, but the type of defect repair (patch or muscle flap) and patch material (non-absorbable, synthetic or absorbable, biological) remain subjects of debate. Increased experience and improved techniques in minimally invasive surgery (MIS) have expanded selection criteria for thoracoscopic defect repair in cardiopulmonary stable patients with small defects. However, the application of MIS to repair large defects remains controversial due to increased recurrence rates and unknown long-term effects of perioperative hypercapnia and acidosis resulting from capnothorax and reduced ventilation. Current recommendations on the surgical management rely on cohort studies of varying patient numbers and data on the long-term outcomes are sparse. Here, we discuss surgical approaches for diaphragmatic defect repair highlighting advancements, and knowledge gaps in surgical techniques (open surgery and MIS), patch materials and muscle flaps for large defects, as well as procedural adjuncts and management of CDH variants.

Patches in Congenital Diaphragmatic Hernia: Systematic Review

OBJECTIVE

This systematic review aims to evaluate current choices in practice and outcomes of biomaterials used in patch repair of congenital diaphragmatic hernia (CDH).

BACKGROUND

Multiple biomaterials, both novel and combinations of pre-existing materials are employed in patch repair of large size CDHs.

METHODS

A literature search was performed across Embase, Medline, Scopus, and Web of Science. Publications that explicitly reported patch repair, material used, and recurrences following CDH repair were selected.

RESULTS

Sixty-three papers were included, presenting data on 4595 patients, of which 1803 (39.2%) were managed using 19 types of patches. Goretex® (GTX) (n=1106) was the most frequently employed patch followed by Dualmesh® (n=267), Surgisis® (n=156), Marlex®/GTX® (n=56), Tutoplast dura® (n=40), Dacron® (n=34), Dacron®/GTX® (n=32), Permacol® (n=24), Teflon® (n=24), Surgisis®/GTX® (n=15), Sauvage® Filamentous Fabric (n=13), Marlex® (n=9), Alloderm® (n=8), Silastic® (n=4), Collagen coated Vicryl® mesh (CCVM) (n=1), Mersilene® (n=1), and MatriStem® (n=1) Biomaterials were further subgrouped as: synthetic nonresorbable (SNOR) (n=1458), natural resorbable (NR) (n=241), combined natural and synthetic nonresorbable (NSNOR) (n=103), and combined natural and synthetic resorbable (NSR) (n=1). The overall recurrence rate for patch repair was 16.6% (n=299). For patch types with n>20, recurrence rate was lowest in GTX/Marlex (3.6%), followed by Teflon (4.2%), Dacron (5.6%), Dualmesh (12.4%), GTX (14.8%), Permacol (16.0%), Tutoplast Dura (17.5%), SIS/GTX (26.7%), SIS (34.6%), and Dacron/GTX (37.5%).When analyzed by biomaterial groups, recurrence was highest in NSR (100%), followed by NR (31.5%), NSNOR (17.5%), and SNOR the least (14.0%).

CONCLUSION

In this cohort, over one-third of CDH were closed using patches. To date, 19 patch types/variations have been employed for CDH closure. GTX is the most popular, employed in over 60% of patients; however, excluding smaller cohorts (n<20), GTX/Marlex is associated with the lowest recurrence rate (3.6%). SNOR was the material type least associated with recurrence, while NSR experienced recurrence in every instance.

Diaphragmatic hernia repair porcine model to compare the performance of biodegradable membranes against Gore-Tex®

BACKGROUND

Patch repair of congenital diaphragmatic hernia (CDH) using Gore-Tex® is associated with infection, adhesions, hernia recurrence, long-term musculoskeletal sequels and poor tissue regeneration. To overcome these limitations, the performance of two novel biodegradable membranes was tested to repair CDH in a growing pig model.

METHODS

Twelve male pigs were randomly assigned to 3 different groups of 4 animals each, determined by the type of patch used during thoracoscopic diaphragmatic hernia repair (Gore-Tex®, polycaprolactone electrospun membrane-PCLem, and decellularized human chorion membrane-dHCM). After 7 weeks, all animals were euthanized, followed by necropsy for diaphragmatic evaluation and histological analysis.

RESULTS

Thoracoscopic defect creation and diaphragmatic repair were performed without any technical difficulty in all groups. However, hernia recurrence rate was 0% in Gore-Tex®, 50% in PCLem and 100% in dHCM groups. At euthanasia, Gore-Tex® patches appeared virtually unchanged and covered with a fibrotic capsule, while PCLem and dHCM patches were replaced by either floppy connective tissue or vascularized and floppy regenerated membranous tissue, respectively.

CONCLUSION

Gore-Tex® was associated with a higher survival rate and lower recurrence. Nevertheless, the proposed biodegradable membranes were associated with better tissue integration when compared with Gore-Tex®.

Evaluation of a biodegradable polyurethane patch for repair of diaphragmatic hernia in a rat model: A pilot study

INTRODUCTION

Congenital diaphragmatic hernia (CDH) repair is an area of active research. Large defects requiring patches have a hernia recurrence rate of up to 50%. We designed a biodegradable polyurethane (PU)-based elastic patch that matches the mechanical properties of native diaphragm muscle. We compared the PU patch to a non-biodegradable Gore-Tex™ (polytetrafluoroethylene) patch.

METHODS

The biodegradable polyurethane was synthesized from polycaprolactone, hexadiisocyanate and putrescine, and then processed into fibrous PU patches by electrospinning. Rats underwent 4 mm diaphragmatic hernia (DH) creation via laparotomy followed by immediate repair with Gore-Tex™ (n = 6) or PU (n = 6) patches. Six rats underwent sham laparotomy without DH creation/repair. Diaphragm function was evaluated by fluoroscopy at 1 and 4 weeks. At 4 weeks, animals underwent gross inspection for recurrence and histologic evaluation for inflammatory reaction to the patch materials.

RESULTS

There were no hernia recurrences in either cohort. Gore-Tex™ had limited diaphragm rise compared to sham at 4 weeks (1.3 mm vs 2.9 mm, p = 0.003), but no difference was found between PU and sham (1.7 mm vs 2.9 mm, p = 0.09). There were no differences between PU and Gore-Tex™ at any time point. Both patches formed an inflammatory capsule, with similar thicknesses between cohorts on the abdominal (Gore-Tex™ 0.07 mm vs. PU 0.13 mm, p = 0.39) and thoracic (Gore-Tex™ 0.3 mm vs. PU 0.6 mm, p = 0.09) sides.

CONCLUSION

The biodegradable PU patch allowed for similar diaphragmatic excursion compared to control animals. There were similar inflammatory responses to both patches. Further work is needed to evaluate long-term functional outcomes and further optimize the properties of the novel PU patch in vitro and in vivo.

LEVEL OF EVIDENCE

Level II, Prospective Comparative Study.

The use of biological membranes for correction of congenital malformations

Many congenital malformations often require a multidisciplinary and multistep surgical treatment, including the use of biological membranes. Aims of the study were to describe the use of these membranes for the correction of malformations, their clinical performance at follow-up, and patient's tolerance to them. The study included patients treated between 2009 and November 2020 in two referral centers. They were affected by abdominal wall defects (AWD), esophageal atresia/tracheo-esophageal fistula (EA/TEF), diaphragmatic hernia (CDH), spinal defects (SD), and anorectal malformations (ARM). The human origin membranes used during surgery were amniotic membrane, fascia lata, and pericardium provided by the local tissue bank and the porcine-derived membrane available on the market. Thirty-one patients were retrieved. The sample included 10 AWD, 7 EA/TEF, 5 CDH, 4 SD, 2 ARM, and 3 miscellaneous defects. The median age at repair was 139 days (range: 10,5–1494). The median follow-up was 1021 days (range: 485,5–1535). Two patients were lost at follow-up. The defects were successfully repaired and the membranes perfectly tolerated in 28/29 cases. In 1 case of CDH the fascia lata was replaced with a Goretex patch due to recurrence of the defect. This is the largest series on the use of biological membranes in congenital malformations. The variety of tissues allows to choose the best material for each malformation. The excellent tolerance and performance of this first series of patients encourage the use of these membranes to correct different type of malformations at any age.

Design of New Concept of Knitted Hernia Implant

A knitted implant, unilaterally modified with plasma-assisted chemical-vapor deposition (PACVD), and with a nano-layer of fluorine derivative supplementation, for reducing the risk of complications related to adhesions, and the formation of a thick postoperative scar was prepared. The biological evaluation of designed or modified medical devices is the main aspect of preclinical research. If such studies use a medical device with prolonged contact with connective tissue (more than 30 days), biocompatibility studies require a safety assessment in terms of toxicity in vitro and in vivo, allergenicity, irritation, and cancerogenicity, reproductive and developmental toxicity. The ultimate aspect of biological evaluation is biofunctionality, and evaluation of the local tissue response after implantation, resulting in the determination of all aspects of local biocompatibility with the implemented synthetic material. The implantation of PACVD-modified materials in muscle allows us to estimate the local irritation effect on the connective tissue, determining the risk of scar formation, whereas implantation of the above-mentioned knitted fabric into the abdominal wall, assists with evaluating the risk of fistula formation-the main post-surgical complications. The research aimed to evaluate the local reaction of the soft tissues after the implantation of the knitted implants modified with PACVD of the fluoropolymer in the nanostuctural form. The local effect that occurred during the implantation of the designed implants was quantitatively and qualitatively evaluated when PACVD unmodified (reference), and modified medical devices were implanted in the abdominal cavity (intra-abdominal position) for 12 or into the muscles for 56 weeks. The comparative semi-quantitative histological assessment included the severity of inflammatory cells (multinucleated cells, lymphocytes, plasma cells, macrophages, giant cells) and the tissue response (necrosis, neovascularization, fibrosis, and fat infiltration) on a five-point scale. The knitted implants modified by PACVD did not indicate cumulative tissue response when they were implanted in the muscle and intra-abdominally with direct contact with the viscera. They reduced local tissue reaction (score -2.71 after 56 weeks of the implantation) and internal organ adhesion (irritation score -2.01 and adhesion susceptibility -0.3 after 12 weeks of the implantation) compared with the reference (unmodified by PACVD) knitted implant, which had an identical structure and was made of the same source.

Recurrence of Congenital Diaphragmatic Hernia: Risk Factors, Management, and Future Perspectives

Recurrence is one of the most common surgical complications in Congenital Diaphragmatic Hernia (CDH). It could remain clinically silent for a long time or present as an acute complication week, months, or even years after the primary surgery. Several risk factors have been identified so far. An extended diaphragmatic defect represents one of the leading independent risk factors, together with indirect signs of large defect such as the liver position related to the diaphragm and the use of the prosthetic patch and with the use of a minimally invasive surgical (MIS) approach. However, the exact contribution of each factor and the overall risk of recurrence during the life span still need to be fully understood. This mini-review aims to give an overview of the current knowledge regarding CDH recurrence, focusing on predisposing factors, clinical presentation, management and follow-up of high-risk patients, and future perspectives.

Biological versus synthetic patch for the repair of congenital diaphragmatic hernia: 8-year experience at a tertiary center

PURPOSE

The aim of this study is to compare outcome between small intestinal submucosal (SIS) and polytetrafluoroethylene (PTFE) patches in patients with congenital diaphragmatic hernia (CDH) with large muscular defects.

MATERIAL AND METHODS

We performed a retrospective review of prospectively collected data of patients who underwent CDH repair from January 2011 to June 2019, with a minimum follow-up of 1 year. Data were collected regarding length of stay (LOS), mortality and recurrence. Kaplan-Meier analyses was used.

RESULTS

In the study period, 195 patients with CDH were admitted, 176 underwent surgical repair and 19 died before surgery. Sixty-two (35%) required a patch. Over the last 5 years, our institution transitioned from the use of all SIS to all PTFE. SIS was used in 18 cases and PTFE in 25. Overall survival rate was 89% (174/195). There was no significant difference regarding LOS and mortality. Nine patients (50%) of SIS and 1 (4%) of PTFE repairs recurred (P < 0.01; log-rank test P <  0.01), with a time course of recurrence of 18 (SD = 13) and 8 months, respectively. Median follow-up was 60 months (SD: 23) for the SIS group and 26 (SD: 10) for the PTFE group.

CONCLUSION

A significant lower recurrence was found using PTFE patches instead of SIS for the repair of large CDH.

LEVEL OF EVIDENCE

Level 3. Retrospective comparative study.

A systematic review and meta-analysis of surgical morbidity of primary versus patch repaired congenital diaphragmatic hernia patients

Large studies comparing the surgical outcome of primary versus patch repair in congenital diaphragmatic hernia (CDH) patients are rare. This study aims to evaluate the incidence of surgical complications in both types of CDH repair. PubMed, EMBASE, Cochrane and Web of Science were searched for peer-reviewed articles. Studies on CDH between 1991 and August 2020 were systematically screened and meta-analyses were performed. Primary outcomes of this review were: haemorrhage, chylothorax, recurrences and small bowel obstruction (SBO). A total of 6436 abstracts were screened, after which 25 publications were included (2910 patients). Patch repaired patients have a 2.8 times higher risk on developing a recurrence (20 studies) and a 2.5 times higher risk on developing a chylothorax (five studies). Moreover, they have a two times higher risk on developing a SBO. No studies could be included that evaluated the incidence of surgical haemorrhage between these patients. Although the quality of the studies was relatively low, patch repaired patients have a higher risk on developing a recurrence, chylothorax and small bowel obstruction. Large prospective studies are required to adjust for severity of disease, to reveal the true causative factors in order to minimize the risk on these surgical complications in both types of patients.

The Role of Mesh Implants in Surgical Treatment of Parastomal Hernia

A parastomal hernia is a common complication following stoma surgery. Due to the large number of hernial relapses and other complications, such as infections, adhesion to the intestines, or the formation of adhesions, the treatment of hernias is still a surgical challenge. The current standard for the preventive and causal treatment of parastomal hernias is to perform a procedure with the use of a mesh implant. Researchers are currently focusing on the analysis of many relevant options, including the type of mesh (synthetic, composite, or biological), the available surgical techniques (Sugarbaker’s, “keyhole”, or “sandwich”), the surgical approach used (open or laparoscopic), and the implant position (onlay, sublay, or intraperitoneal onlay mesh). Current surface modification methods and combinations of different materials are actively explored areas for the creation of biocompatible mesh implants with different properties on the visceral and parietal peritoneal side. It has been shown that placing the implant in the sublay and intraperitoneal onlay mesh positions and the use of a specially developed implant with a 3D structure are associated with a lower frequency of recurrences. It has been shown that the prophylactic use of a mesh during stoma formation significantly reduces the incidence of parastomal hernias and is becoming a standard method in medical practice.

Porcine dermal patches as a risk factor for recurrence after congenital diaphragmatic hernia repair

PURPOSE

Recurrence of congenital diaphragmatic hernia (CDH) is a treatment-related morbidity which can be preventable. There is no consensus about the ideal material for diaphragmatic substitution. The aim of our study is to identify if the use of porcine dermis patches increases the risk of CDH recurrence.

METHODS

Retrospective review of medical records of CDH patients treated between 2013 and 2017 in our center was carried out. Demographic, clinical and surgical variables were collected. Regression analysis was performed to identify which factors increase the risk of recurrence.

RESULTS

50 patients entered the study. 94% of the patients had a left CDH, mean observed/expected lung-to-head ratio was 46%. 17 patients underwent a primary closure, the rest a patch closure: 25 Gore-Tex^® and 8 porcine dermis patches were used. Seven patients presented recurrence (14%). Median follow-up time was 3.5 years (1.2-6.2). Univariate analysis revealed that the use of a porcine dermis patch (75%) increased the risk of recurrence compared with Gore-Tex^® patch (4%) and primary closure (0%) p < 0.001 (HR 58.7; IC 95%: 6.9-501.2; p < 0.001).

CONCLUSION

The main risk factor for CDH recurrence is the use of a porcine dermis patch. We do not recommend the use of these patches for CDH repair.

Longitudinal Follow-Up With Radiologic Screening for Recurrence and Secondary Hiatal Hernia in Neonates With Open Repair of Congenital Diaphragmatic Hernia-A Large Prospective, Observational Cohort Study at One Referral Center

Objective: After neonatal repair of congenital diaphragmatic hernia (CDH) recurrence is the most severe surgical complication and reported in up to 50% after patch implantation. Previous studies are difficult to compare due to differences in surgical techniques and retrospective study design and lack of standardized follow-up or radiologic imaging. The aim was to reliably detect complication rates by radiologic screening during longitudinal follow-up after neonatal open repair of CDH and to determine possible risk factors. Methods: At our referral center with standardized treatment algorithm and follow-up program, consecutive neonates were screened for recurrence by radiologic imaging at defined intervals during a 12-year period. Results: 326 neonates with open CDH repair completed follow-up of a minimum of 2 years. 68 patients (21%) received a primary repair, 251 (77%) a broad cone-shaped patch, and 7 a flat patch (2%). Recurrence occurred in 3 patients (0.7%) until discharge and diaphragmatic complications in 28 (8.6%) thereafter. Overall, 38 recurrences and/or secondary hiatal hernias were diagnosed (9% after primary repair, 12.7% after cone-shaped patch; p = 0.53). Diaphragmatic complications were significantly associated with initial defect size (r = 0.26). In multivariate analysis left-sided CDH, an abdominal wall patch and age below 4 years were identified as independent risk factors. Accordingly, relative risks (RRs) were significantly increased [left-sided CDH: 8.5 (p = 0.03); abdominal wall patch: 3.2 (p < 0.001); age ≤4 years: 6.5 (p < 0.002)]. 97% of patients with diaphragmatic complications showed no or nonspecific symptoms and 45% occurred beyond 1 year of age. Conclusions: The long-term complication rate after CDH repair highly depends on surgical technique: a comparatively low recurrence rate seems to be achievable in large defects by implantation of a broad cone-shaped, non-absorbable patch. Longitudinal follow-up with regular radiologic imaging until adolescence is essential to reliably detecting recurrence to prevent acute incarceration and chronic gastrointestinal morbidity with their impact on prognosis. Based on our findings and literature review, a risk-stratified approach to diaphragmatic complications is proposed.

Application of computer tomography-based 3D reconstruction technique in hernia repair surgery

BACKGROUND

Hernia is a common condition requiring abdominal surgery. The current standard treatment for hernia is tension-free repair using meshes. Globally, more than 200 new types of meshes are licensed each year. However, their clinical applications are associated with a series of complications, such as recurrence (10% - 24%) and infection (0.5% - 9.0%). In contrast, 3D-printed meshes have significantly reduced the postoperative complications in patients. They have also shortened operating time and minimized the loss of mesh materials. In this study, we used the myopectineal orifice (MPO) data obtained from preoperative computer tomography (CT)-based 3D reconstruction for the production of 3D-printed biologic meshes.

AIM

To investigate the application of multislice spiral CT-based 3D reconstruction technique in 3D-printed biologic mesh for hernia repair surgery.

METHODS

We retrospectively analyzed 60 patients who underwent laparoscopic tension-free repair for inguinal hernia in the Department of General Surgery of the First Hospital of Shanxi Medical University from September 2019 to December 2019. This study included 30 males and 30 females, with a mean age of 40 ± 5.6 years. Data on the MPO were obtained from preoperative CT-based 3D reconstruction as well as from real-world intraoperative measurements for all patients. Anatomic points were set for the purpose of measurement based on the definition of MPO: A: The pubic tubercle; B: Intersection of the horizontal line extending from the summit of the inferior edge of the internal oblique and transversus abdominis and the outer edge of the rectus abdominis, C: Intersection of the horizontal line extending from the summit of the inferior edge of the internal oblique and transversus abdominis and the inguinal ligament, D: Intersection of the iliopsoas muscle and the inguinal ligament, and E: Intersection of the iliopsoas muscle and the superior pubic ramus. The distance between the points was measured. All preoperative and intraoperative data were analyzed using the t test. Differences with P < 0.05 were considered significant in comparative analysis.

RESULTS

The distance between points AB, AC, BC, DE, and AE based on preoperative and intraoperative data was 7.576 ± 0.212 cm vs 7.573 ± 0.266 cm, 7.627 ± 0.212 cm vs 7.627 ± 0.212 cm, 7.677 ± 0.229 cm vs 7.567 ± 0.786 cm, 7.589 ± 0.204 cm vs 7.512 ± 0.21 cm, and 7.617 ± 0.231 cm vs 7.582 ± 0.189 cm, respectively. All differences were not statistically significant (P > 0.05).

CONCLUSION

The use of multislice spiral CT-based 3D reconstruction technique before hernia repair surgery allows accurate measurement of data and relationships of different anatomic sites in the MPO region. This technique can provide precise data for the production of 3D-printed biologic meshes.

Innovative, Stabilizing Self-Expandable Patch for Easier and Safer Thoracoscopic Repair of Congenital Diaphragmatic Hernia

Introduction: Thoracoscopic repair of congenital diaphragmatic hernia (CDH) has become a popular approach and several benefits have been published. Patch closure requires demanding thoracoscopic skills and therefore primary closure with tight sutures is often pursued, which increases the risk of recurrence. The purpose of this study was to create and assess the performance of a new technique for thoracoscopic repair of CDH, which facilitates the surgical procedure. Materials and Methods: An innovative system for thoracoscopic repair of CDH with a novel patch was developed. The patch is self-expandable and offers a traction suture for stabilization, isolating and protecting the viscera. Its performance was assessed and compared with a conventional patch in an inanimate model of the disease through a quantitative and qualitative multivariate analysis. Results: Nine cases of CDH were repaired with each patch. The duration of the procedure was shorter (P < .05) and the level of difficulty was reported to be lower (P < .001) when using the self-expandable patch (SeP). The number of good quality knots was higher and adverse events were less common with this new technique. Conclusions: The stabilizing SeP offers safe and ergonomic performance for thoracoscopic CDH repair, facilitating the surgical technique. The main advantage is that it keeps the viscera isolated into the abdomen while offering a flap on the thoracic side for suturing in a practical manner, minimizing the risk of visceral injury and saving surgical time.

Biomaterials in fetal surgery

Fetal surgery and fetal therapy involve surgical interventions on the fetus in utero to correct or ameliorate congenital abnormalities and give a developing fetus the best chance at a healthy life. Historical use of biomaterials in fetal surgery has been limited, and most biomaterials used in fetal surgeries today were originally developed for adult or pediatric patients. However, as the field of fetal surgery moves from open surgeries to minimally invasive procedures, many opportunities exist for innovative biomaterials engineers to create materials designed specifically for the unique challenges and opportunities of maternal-fetal surgery. Here, we review biomaterials currently used in clinical fetal surgery as well as promising biomaterials in development for eventual clinical translation. We also highlight unmet challenges in fetal surgery that could particularly benefit from novel biomaterials, including fetal membrane sealing and minimally invasive myelomeningocele defect repair. Finally, we conclude with a discussion of the underdeveloped fetal immune system and opportunities for exploitation with novel immunomodulating biomaterials.