Large-sized Defects Research Articles

OC-038 RISK FOR CONTRALATERAL INGUINAL HERNIA REPAIR FOLLOWING PRIMARY UNILATERAL HERNIA REPAIR – A REGISTER-BASED STUDY

Abstract Aim To investigate the incidence as well as the factors predictive for a subsequent hernia repair on the contralateral side following a primary unilateral hernia repair. Material & Methods Prospective population-based study of data from the Swedish Hernia Register based on 151,297 patients operated with an index unilateral inguinal hernia mesh repair using open and endo-laparoscopic technique, during 2007–2019. Incidence, predictive factors and time to a contralateral hernia repair was analysed. Results There were 7.4% registered contralateral hernia repairs with a median time of 2.7 years to a subsequent contralateral repair following the index unilateral hernia repair. Median follow-up time was 7.5 years. Significant predictors for a subsequent contralateral hernia were, male sex (HR 1.78, 95% CI 1.61–1.97), high age (HR 1.01 95% CI 1.006–1.009), medial inguinal hernia (HR 1.05, 95% CI 1.003–1.098), combined inguinal hernia (HR 1.10, 95% CI 1.03–1.18), hernia defect size 1.5–3.0 cm (HR 1.10, 95% CI 1.03–1.17), hernia defect size > 3 cm (HR 1.36, 95% CI 1.27–1.45) and a repair on the left side (HR 1.30, 95% CI 1.25–1.35). Endo-laparoscopic repairs and obesity were associated with a lower incidence of a later contralateral repair. Conclusion If the relevant risk factors, i.e., male sex, high age, large hernia defect size, medial or combined hernia, are present at a unilateral endo-laparoscopic groin hernia repair and the decision has been shared with the patient, exploration of the contralateral groin and prophylactic mesh placement may be considered.

A rare case of an Omphalocele Major with associated Tetralogy of Fallot in a newborn

Omphalocele major (OM) is a surgically challenging condition which owing to its large defect size and other congenital anomalies, is associated with poor outcomes. Complications while managing it are not uncommon. But here, we report a case of OM in a neonate who was successfully managed in a multidisciplinary approach by a team of neonatologist, surgeons and anesthetist.

Fungal Keratitis: Clinical Features, Risk Factors, Treatment, and Outcomes.

Fungal keratitis (FK) can be challenging to diagnose and treat. In this retrospective case series, FK cases presenting at the University of Pittsburgh Medical Center, Pennsylvania, USA, from 2015 to 2021 were reviewed for ocular risk factors, clinical presentation, management, and outcomes. Twenty-eight cases of FK were included. The median presenting age was 58.5 (18.5) years, and the median symptom duration prior to presentation was 10 (35.8) days. Predisposing ocular risk factors included contact lens use (67.9%), recent ocular trauma/abrasion (42.9%), and history of ocular surgery (42.9%). The median presenting visual acuity (VA) was 1.35 (1.72) LogMAR. About half presented with a central ulcer (42.9%), large infiltrate (6.7 (6.3) mm2), corneal thinning (50.0%), and hypopyon (32.1%). The majority of isolated fungal species were filamentous (75.0%). Most common antifungal medications included topical voriconazole (71.4%) and natamycin (53.6%) drops and oral voriconazole (64.3%). Surgical management was necessary in 32.1% of cases and enucleation in one case. Defect resolution occurred in 42.5 (47.0) days, and median final VA was 0.5 (1.84) LogMAR. Features associated with poor final visual outcomes included poor initial VA (p < 0.001) and larger defect size (p = 0.002). In conclusion, unlike prior studies in the northeast region of the USA, FK was commonly caused by filamentous fungi, and antifungal management most often consisted of topical and oral voriconazole.

Dual role of injectable curcumin-loaded microgels for efficient repair of osteoarthritic cartilage injury.

Curcumin has been widely used for the treatment of age-associated diseases, and showed chondroprotective potential for post-traumatic osteoarthritis (OA). However, due to the irregular-shaped and large-sized defects on joint cartilage in degenerated OA, the in vivo delivery and therapeutic effect of curcumin for effective repair remain challenging. In this study, we first present a PEG-GelMA [Poly(Ethylene Glycol) Dimethacrylate-Gelatin Methacrylate, PGMs] hydrogel microgel-based curcumin delivery system for both improved anti-inflammatory and pro-regenerative effects in treatment for cartilage defects. The curcumin-loaded PGMs were produced by a microfluidic system based on light-induced gelation of gelatin methacrylate (GelMA). This PGMs embedding curcumin at a relative low dosage were demonstrated to promote the proliferation and chondrogenic differentiation of mesenchymal stem cells in vitro. More importantly, the PGMs were shown to attenuate the inflammatory response of chondrocytes under IL-1β stimulation. Lastly, the in vivo application of the injectable PGMs significantly promoted the repair of large-sized cartilage injury. These results confirmed that curcumin-loaded PGMs can not only enhance the chondroprotective efficacy under inflammatory conditions but also induce efficient cartilage regeneration. This study provides an advanced strategy with anti-inflammatory and pro-regenerative dual-role therapeutic for treatment of extensive cartilage injuries.

Iatrogenic Atrial Septal Defect Closure Through the Steerable Guide Catheter: Description of Technique and Single-Center Experience.

To introduce a novel method of direct iatrogenic atrial septal defect (iASD) closure through the MitraClip steerable guide catheter (SGC). MitraClip implantation requires transseptal puncture and the creation of an iASD. There are relatively rare instances, such as hemodynamically significant shunting or concerns for embolus, where iASD must be closed during index procedure. In these instances, it may be beneficial to not give up access to left atrium. We retrospectively reviewed all iASD closures during MitraClip implantation at our institution from 2015 to 2020. Cases where an ASD occluder was deployed directly through SGC were included. Eleven patients had immediate iASD closure through the SGC. Indications for using this method included concern for paradoxical embolus, large defect size and/or significant shunting. Closure device sizes ranged from 8 to 22 mm. Mean time from removal of clip delivery system to occlusion of iASD was 14.6 minutes. There were no procedural complications related to iASD closure using this method. Closure of iASD intra-procedurally directly through transseptal guide sheath via the method described was safe and allowed for continuous left atrium access.

Enhancement of critical-sized bone defect regeneration using UiO-66 nanomaterial in rabbit femurs

BackgroundRepair of large-sized bone defects is a challengeable obstacle in orthopedics and evoked the demand for the development of biomaterials that could induce bone repair in such defects. Recently, UiO-66 has emerged as an attractive metal–organic framework (MOF) nanostructure that is incorporated in biomedical applications due to its biocompatibility, porosity, and stability. In addition, its osteogenic properties have earned a great interest as a promising field of research. Thus, the UiO-66 was prepared in this study and assessed for its potential to stimulate and support osteogenesis in vitro and in vivo in a rabbit femoral condyle defect model. The nanomaterial was fabricated and characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM). Afterward, in vitro cytotoxicity and hemolysis assays were performed to investigate UiO-66 biocompatibility. Furthermore, the material in vitro capability to upregulate osteoblast marker genes was assessed using qPCR. Next, the in vivo new bone formation potential of the UiO-66 nanomaterial was evaluated after induction of bone defects in rabbit femoral condyles. These defects were left empty or filled with UiO-66 nanomaterial and monitored at weeks 4, 8, and 12 after bone defect induction using x-ray, computed tomography (CT), histological examinations, and qPCR analysis of osteocalcin (OC) and osteopontin (OP) expressions.ResultsThe designed UiO-66 nanomaterial showed excellent cytocompatibility and hemocompatibility and stimulated the in vitro osteoblast functions. The in vivo osteogenesis was enhanced in the UiO-66 treated group compared to the control group, whereas evidence of healing of the treated bone defects was observed grossly and histologically. Interestingly, UiO-66 implanted defects displayed a significant osteoid tissue and collagen deposition compared to control defects. Moreover, the UiO-66 nanomaterial demonstrated the potential to upregulate OC and OP in vivo.ConclusionsThe UiO-66 nanomaterial implantation possesses a stimulatory impact on the healing process of critical-sized bone defects indicating that UiO-66 is a promising biomaterial for application in bone tissue engineering.

Successful Perforator-Based Island Flap Placement Using the Push Technique

Background: Several surgical options are available for covering soft tissue defects. Perforator-based flaps can be utilized without skeletonization of the perforator, and surgery is usually straightforward, albeit with limited arcs of rotation. To overcome this limitation, we present our experience of the push technique, whereby the flap is manually pushed to release soft tissue attachments, allowing circumvention of the meticulous dissection required to enhance arc rotation. This technique allows faster flap elevation with minimal complications.Methods: The records of 37 patients that underwent perforator-based flap surgery using the push technique from September 2020 to June 2021 at our institution were retrospectively reviewed.Results: All 38 flaps survived completely though one flap developed congestion resulting in partial necrosis and revision. Mean operation time was less than 80 minutes. No dehiscence or recurrence was encountered at any donor or recipient site during follow-up.Conclusion: We present the “push technique” used during perforator-based flap surgery. This method allows for efficient, minimal, and rapid flap elevation without meticulous dissection and helps the operator determine which parts of soft tissue attachments require further release. The push technique can be performed safely and easily without jeopardizing flap survival due to venous ischemic or congestive change. It serves as a good practice model for inexperienced surgeons wishing to cover moderate-to large-sized defects.

Large defect size is associated with 30-day mortality following surgical repair of congenital diaphragmatic hernia

Journal of Neonatal Surgery is a peer-reviewed and open-access electronic journal. Only a few journals are being published on Neonatal Surgery especially from a developing country, which justifies the need of a new journal on this subject.

Bioactive glass granules versus standard autologous and allogeneic bone grafts: a randomized trial of 49 adult bone tumor patients with a 10-year follow-up.

As a synthetic bone void filler, bioactive glasses (BGs) may enhance angiogenesis and osteogenesis. In this randomized trial, we compared the clinical efficacy of BG granules and standard bone grafts in patients undergoing surgery for benign bone tumors. 49 recruited patients were randomized to receive BG granules or undergo conventional bone grafting to fill defects following tumor removal. As the standard of care, small-sized defects were filled with autologous graft, and large-sized defects were filled with allogeneic graft. The primary endpoint was treatment success at 1 year, defined by no reoperation, no tumor recurrence, and no device-related adverse events. Secondary endpoints included patient-reported outcomes (Rand-36 and pain scores) and quantitative assessment of blood flow and metabolic activity by means of 18F-fluoride PET/CT imaging. As an off-trial group, 15 children and adolescents (age < 18 years) underwent tumor removal and BG-filling, without randomization. At 1-year, 21 of 25 BG-treated patients (risk estimate 0.84, 95% confidence interval [CI] 0.70-0.98) and 20 of 24 patients in the standard of care group (0.83, CI 0.68-0.98) met the criteria for treatment success. The groups had similar Rand-36 scores. In patients with small defects, BG filling was associated with shorter operative time and less postoperative pain at 1 month. In patients with large defects, blood flow was similar, but BG-filled defects showed higher metabolic activity than allograft-filled defects at 1-year. The survey of the postoperative period ≥10 years revealed no BG-related adverse events. BG granules had similar overall rates of treatment success compared with autografts and allografts, but large-scale trials are needed for the confirmation of clinical equivalence. The extended metabolic activity confirms the expected cellular responses of osseointegrated BG granules.

Effects of adding GPLs dispersed at different sonication times on the thermal and electrical conductivities of spark plasma sintered silicon carbide

This study has investigated the effects of adding 1 wt % graphene platelets (GPLs) dispersed at different probe-sonication times such as 1, 2, 4 and 6 h on the microstructure, thermal and electrical conductivities of the spark plasma sintered (SPSed) silicon carbide (SiC) matrix. According to scanning electron microscope (SEM), size measurement and Raman analyses, the dispersion of the GPLs increased, the platelet sizes decreased, and the defect concentrations on the structure of GPLs increased as the sonication time increased. While the size reduction was only around 2–5% up to 2 h sonication time, it increased to 25–30% at the 4 and 6 h sonication times. 2 h sonicated GPLs provided the highest contribution among all GPLs, increasing the thermal and electrical conductivity of the SiC matrix by 24 % and ∼106 times, respectively due to having a combination of large lateral size, good dispersion, and low defect concentration characteristics. Anisotropic effect on thermal and electrical conductivities of GPLs-SiC composites decreased with increasing probe-sonication time since the reduction in platelet size of GPLs led to a decrease in their orientation degree within the matrix microstructure.

Temperature-controlled exfoliation of graphite oxide: studies of defects and transport properties of graphene oxide

The quality, structural defects, and transport properties of GO can be tailored by maintaining ultrasonic bath temperature. Herein, the effect of temperature-controlled exfoliation on the structural defects and transport properties of the resulting graphene oxide (GO) sheets are examined. The large crystallite size (12.23 nm) and low defect density (2.16 × 1011 cm−2) are found at 20 °C exfoliations. Highly oriented GO sheets were exfoliated at 20 °C which was confirmed through Bernal-stacking proportions (∼30%). Furthermore, electrical transport properties are high at 10 °C exfoliation temperature while optimum at other temperatures, calculated through impedance spectroscopy. Comparatively, smooth, wrinkle-free, and lesser bulges are found at 20 °C and 30 °C exfoliation temperatures.

Supraventricular Tachycardia in Infants With Congenital Diaphragmatic Hernia: Prevalence, Associations, and Outcomes.

To characterize the prevalence, associations, management, and outcomes of supraventricular tachycardia (SVT) in neonates with congenital diaphragmatic hernia (CDH). Retrospective chart and cardiology code review within a cohort of patients with CDH was used to define a subpopulation with atrial arrhythmia. SVT mechanisms were confirmed by electrocardiogram analysis. Cox proportional hazard regression identified risk factors for SVT and association with clinical outcomes. Medical Surgical ICU in a single, tertiary center, Boston Children's Hospital. Eligible patients included neonates presenting with classic Bochdalek posterolateral CDH between 2005 and 2017, excluding newborns with Morgagni hernia or late diagnoses of CDH (>28 d). None. SVT arose in 25 of 232 neonates with CDH, (11%); 14 of 25 infants (56%) had recurrent SVT; atrioventricular node-dependent tachycardia was the most frequent mechanism (32%). The majority (71%) of SVT episodes received intervention. Nine patients (36%) received preventative antiarrhythmic medications. SVT was associated with lower Apgar score at 1 min, structural heart disease, larger defect size, extracorporeal membrane oxygenation (ECMO) support, and prostaglandin therapy for ductal patency as well as hospital stay greater than or equal to 8 weeks and use of supplemental oxygen at discharge. SVT can occur in neonates with CDH and frequently requires treatment. Odds of occurrence are increased with greater CDH disease severity, ECMO, and prostaglandin use. In unadjusted logistic regression analysis, SVT was associated with adverse hospital outcomes, underscoring the importance of recognition and management in this vulnerable population.

Double hatchet flap as adequate dermatosurgical approach for tumours of the occipital scalp zone: Presentation of two cases.

Tumors of the scalp remain a serious challenge for clinicians since poor locoregional skin elasticity hinders the ability to utilise certain flaps, limiting the choice of reconstructive techniques available. As a result, surgical restoration of medium to large-sized defects are left to the discretion of the surgeon, who with a comprehensive knowledge of restorative techniques, along with the advantages, limitations as well as a sound understanding of the locoregional anatomy, can make thorough decisions on the choice of which flap is best suited for the defect. Here we present two cases where the double hatchet flap was employed as a dermatosurgical approach in order to provide exceptional cosmetic results. On dermatological examination, both patients presented with a medium to large- sized tumour formation but were otherwise in good health. Both underwent radical, widelocal excision, followed by reconstructive manipulation in the form of a double hatchet flap to close the defect. Postoperative follow- up reported positive signs of wound healing with aesthetically pleasing results. Finally, we discuss the use of various flaps in such conditions while providing evidence for the double hatchet flap as a possible alternative that provides perfect aesthetic results as seen in our cases. Such a complex surgical intervention requires the expertise of a multidisciplinary team in order to achieve an overall successful outcome.

A Large Segmental Mid-Diaphyseal Femoral Defect Sheep Model: Surgical Technique

Background:There are numerous animal models available to study bone healing as well as test strategies to accelerate bone formation. Sheep are commonly used for evaluation of long bone fractures due to similar dimensions and weight bearing environments compared to patients. Large critical-size defects can be created in sheep to facilitate the study of implantable materials, osteogenic proteins, and stem cell treatments. Studies have been published using plates to stabilize large critical size defects in femoral, tibial, and metatarsal defects. External fixators have also been used to stabilize tibial defects in sheep.Methods: The purpose of the current paper is to detail the surgical technique for creation of a 42 mm mid-diaphyseal femoral defect stabilization with an intramedullary device in sheep. Additional surgical details are provided for dynamization, reverse dynamization, and device removal.Conclusion: The article provides multiple technical tips applicable to this and other ovine osteotomy models and concludes with a discussion comparing the use of each stabilization technique in clinically significant large critical-size bone defects.

Low serum 25-hydroxyvitamin D (vitamin D) level among children with ventricular septal defect: how big is the risk for pulmonary hypertension?

Ventricular septal defect is the most common CHD, leading to pulmonary hypertension. Significantly lower 25-hydroxyvitamin D level was reported in children with CHD compared with healthy controls. The current study aimed to investigate the correlation between 25-hydroxyvitamin D level and pulmonary hypertension in children with ventricular septal defect. A cross-sectional study was conducted on ventricular septal defect paediatric patients from January to June, 2019. Serum 25-hydroxyvitamin D was measured using electrochemiluminescence. Pulmonary hypertension was defined as mean pulmonary artery systolic pressure > 20 mmHg for children >3 months of age at sea level, measured by Doppler echocardiography. From forty-four subjects, the majority of the subjects were female (56.8%) with normal nutritional status and perimembranous ventricular septal defect. Bivariate analysis showed that 25-hydroxyvitamin D level was associated with pulmonary hypertension (p < 0.01), type and size of ventricular septal defect (p = 0.02), and heart failure (p < 0.01). Higher 25-hydroxyvitamin D level was correlated with better nutritional status (p = 0.04, r = 0.26), and lower 25-hydroxyvitamin D level was correlated with the occurence of perimembranous ventricular septal defect (p = 0.01, r = -0.39), larger defect size (p < 0.01, r = -0.70), history of pneumonia (p = 0.02, r = -0.31), and heart failure (p < 0.01, r = -0.64). Subjects with 25-hydroxyvitamin D deficiency had prevalence ratio of 24.0 times for pulmonary hypertension. Higher pulmonary artery pressure was correlated to the occurence perimembranous ventricular septal defect (p = 0.01, r = 0.47), larger defect size (p < 0.01, r = 0.78), history of pneumonia (p = 0.01, r = 0.38), and heart failure (p < 0.01, r = 0.75). Children with ventricular septal defect who had low 25-hydroxyvitamin D level posed a higher risk of having pulmonary hypertension.

Transversus Abdominis Release Versus Anterior Component Separation in Ventral Abdominal Hernia - A Prospective Comparative Study

Ventral abdominal hernia (VAH) repair is considered a surgical challenge especially hernias with large defect size and loss of domain (1-3). The incidence of recurrence after VAH repair ranges from 18.1% in primary VAH to 30.6% in secondary VAH (incisional hernia) (4). The principle of any hernia repair is to achieve a tension free repair with re-enforcement by mesh to decrease the incidence of recurrence (5). Many techniques had been studied and evaluated to address the problem of complex VAH with large defects and loss domain (1,6). In 1973, Rives et al. described their technique of retro rectus space dissection for incisional hernia (IH) repair allowing medial mobilization of myofascial flap and sub-lay mesh insertion (7, 8). But this technique has limitation in cases of large VAH as it doesn’t allow major myofascial advancement due to lateral limitation of linea semilunaris (LS) (9). In 1990, Ramirez et al. at described their technique of open anterior component separation (ACS) (10). In this technique, the external oblique aponeurosis is separated from internal oblique lateral to LS to achieve more medial mobilization of myofascial flap (9). ACS was successfully utilized in cases of large VAH, but the technique had its drawbacks. ACS was found to be associated with high rates of wound complications (seroma, wound infection, and flap necrosis) due to excess subcutaneous dissection with the possibility of lateral abdominal wall hernia at area of external oblique incision. The recurrence rate after ACS ranges from 9-18% (4). In 2012, Novitsky et al. were the first to describe the technique of posterior component separation and transversus abdominis release (PCS-TAR). The technique involved retro rectus space dissection reaching the LS, then an incision is made at posterior rectus sheath to access the space between internal oblique and transversus abdominis muscles. Dissection is carried on in this space until reaching psoas muscle laterally. This technique has the advantage of allowing maximum medial myofascial mobilization without major subcutaneous dissection. In addition, the technique allows for sub-lay mesh placement (11). All these different component separation techniques aim to reestablish a functional abdominal wall through autologous tissue repair by separating between myofascial layers of anterior abdominal wall (AAW). This allows medial mobilization of myofascial flap to obliterate large size defects (12-14). Due to the relative novelty of these techniques, a knowledge gap still persists regarding which CS technique is suitable to different types of VAH. The aim of our study is to compare the outcomes of TAR with ACS as regard short term postoperative complication and recurrence rate.

Reconstruction of the lower lip after broad oncologic resection by Colmenero flap: a reliable option.

SUMMARYObjectiveReconstruction of the lower lip is complex. The Colmenero flap is an effective albeit rarely described method for the repair of medium- to large-sized defects of the lower lip.MethodsA retrospective review was carried out using data gathered from patients who had undergone Colmenero flap reconstruction of the lower lip at our centre between 2015 and 2020. We analysed demographic, histologic and anatomic variables as well as surgical results. This review assessed flap functionality based on proper mouth closure, absence of microstomia and oral competence.ResultsThirteen Colmenero flaps were performed in 9 patients, with the flap being used bilaterally in four cases. All patients had squamous cell carcinoma of the lower lip. The mean length of the reconstructed defect was 4.1 cm (ranging between 3-7.5 cm). None of the flaps exhibited signs of necrosis. Five patients required minor surgical touch up during the second procedure: two for dehiscence, two for oral leakage and one for esthetic improvement. All patients had excellent functional and aesthetic final outcomes.ConclusionsThe Colmenero flap is a good resource for medium- and large-sized lower lip reconstructions due to its reliability, limited complications, and good aesthetic and functional results.

P162 POLY-4-HYDROXYBUTYRATE MESH (PHASIX MESH) FOR VENTRAL HERNIA REPAIRS: A SINGLE SURGEON RETROSPECTIVE SERIES

Abstract Aim To compare a single-surgeon experience using poly-4-hydroxybutyrate mesh (Phasix™ Mesh) for ventral hernia repairs (VHR). Material and Methods A retrospective series was performed from 2014-2020. Inclusion criteria were patients ≥18 years of age with open VHR using poly-4-hydroxybutyrate mesh, with a minimum follow-up of 12-months. Comparisons were performed between no prior VHR versus prior VHR; no mesh infections versus mesh infections; onlay versus retrorectus; no recurrences versus recurrences; no readmissions versus readmissions; no reoperations versus reoperations. Results Poly-4-hydroxybutyrate mesh was used for VHR in 179 patients. Compared to 90 patients with no prior VHR, 89 patients with prior VHR had higher BMIs (31.1kg/m2versus33.3 kg/m2; p = 0.042). Compared to 146 patients with no mesh infections, 33 patients with mesh infections had more prior VHR (97%versus39%; p &amp;lt; 0.001). Compared to 101 patients with onlay approaches, 79 patients with retrorectus approaches had more component separations (89%versus31%; p &amp;lt; 0.001). Compared to 168 patients with no recurrences, 11 patients with recurrences had more complications (55%versus23%; p = 0.031), reoperations (82%versus16%; p &amp;lt; 0.001), and readmissions (91%versus20%; p &amp;lt; 0.001). Compared to 136 patients with no readmissions, 43 patients with readmissions had more hypertension (81%versus56%; p = 0.004), COPD (28%versus10%; p = 0.011), complications (79%versus8%; p &amp;lt; 0.001), and recurrences (23%versus0.7%; p &amp;lt; 0.001). Compared to 142 patients with no reoperations, 37 patients with reoperations had more hypertension (89%versus55%; p &amp;lt; 0.008), diabetes (43%versus25%; p = 0.042), COPD (30%versus11%; p = 0.007), hyperlipidemia (57%versus32%; p = 0.008), larger defect sizes (300cm2versus200cm2; p = 0.032), complications (78%versus11%; p &amp;lt; 0.001), readmissions (92%versus6%; p &amp;lt; 0.001), and recurrences (24%versus1%; p &amp;lt; 0.001). Conclusions VHR with poly-4-hydroxybutyrate mesh can include prior VHR, different anatomical locations, mesh infections, recurrences, readmissions and reoperations.

An approach to evaluating and benchmarking the mechanical behavior of a surgical mesh prototype designed for the repair of abdominal wall defects

Ventral hernia repair is a common surgical procedure in abdominal surgery in which surgical mesh has become an essential tool to improve outcomes. To avoid recurrences the mesh needs to mimic the mechanical behavior of the abdominal wall. In this scenario the mechanical properties at the interface between the mesh and its surrounding tissue is critical for the performance of the device and, therefore, the success after surgery.We aimed to characterize and compare the mechanical behavior of the patented prototype mesh Spider and four commercial meshes at the mesh–tissue interface. The prototype mesh was designed based on the hypothesis that the best performance for a large-sized defect in a ventral hernia is obtained when the mesh presents an isotropic behavior. In contrast, commercial meshes presented significant anisotropic behavior.Mechanical properties of the meshes were characterized through uniaxial tensile tests. Longitudinal and transverse axes were defined for each mesh, and samples were cut in each axis orientation. Samples underwent uniaxial tensile testing, from which the elastic modulus in each axis was determined. The degree of anisotropy was calculated as the ratio between the elastic modulus in each axis.An in silico model of the ventral hernia defect was designed to simulate the mesh–tissue interface behavior via finite element method. Meshes were modeled by an hyperelastic orthotropic constitutive model, which allowed isotropic symmetry as particular case for the prototype mesh. Abdominal wall was modeled using a Neo-Hookean model. Once the simulations were launched, mesh–tissue interface behavior was evaluated through the difference between Von Mises stress values on either size of the interface, both on the external and the internal face of the mesh and abdominal wall.Mechanical response was anisotropic for all commercial meshes and isotropic for the Spider prototype. Among commercial, Ultrapro® was highly anisotropic. Tests revealed Gore-Tex® to be the stiffest, followed by Repol Angimesh®, Spider and Ultrapro®; Duramesh™ was found to be the most compliant.Concerning mesh–tissue behavior, simulation results revealed the Spider prototype and Duramesh™ to be the best; Spider due to its uniformity and lower stress difference thanks to its nearly isotropic behavior, and Duramesh™ due to its compliant behavior.Our results suggest that the compromise between stiffness and anisotropy must be considered in order to improve the mechanical performance of the meshes, bearing in mind that for large-sized ventral defects, nearly isotropic mesh ensures better performance.

Preservation of Deep Epigastric Perforators during Anterior Component Separation Technique Results in Equivalent Wound Complications Compared with Transversus Abdominis Release

BACKGROUND: In complex abdominal wall reconstruction, the use of CST increases fascial medialization and facilitates fascial closure; however, ACST has been associated with a high rate of wound complications.1 The purpose of this study was to compare wound complications and perioperative outcomes between a perforator sparing (PS)-ACST and (TAR). METHODS: From a prospective, tertiary hernia center database, patients who underwent open abdominal wall reconstruction with PS-ACST or TAR from 2016 to 2020 were identified. Patients undergoing concurrent panniculectomy were excluded. Outcomes included wound complications, need for reintervention, length of stay, and 30-day readmission. The Carolinas Equation for Determining Associated Risks application was used to predict wound complication rates. A univariate analysis was performed between the PS-ACST and TAR groups. Standard statistical methods and logistic regression were performed. RESULTS: A total of 92 patients met criteria; 37 had PS-ACST and 55 had TAR performed. The PS-ACST and TAR groups were similar in terms of BMI (29.8 ± 8.9 versus 31.3 ± 6.3 kg/m2, P = 0.23) and diabetes (16.2% versus 25.5%, P = 0.32), but the PS-ACST group a greater history of smoking (51.4% versus 14.5%, P < 0.01). Both groups had five comorbidities on average (P = 1.00). Most hernias were recurrent (59.5% versus 61.8%, P = 0.83). CDC wound classes were equivalent. The Carolinas Equation for Determining Associated Risks predicted wound complication rates were: PS-ACS-56.9% (range: 14.2–92.9%) and TAR-39.7 % (range: 7.3–92.2%). Preoperative botulinum toxin A was performed in 43.8% versus 19.1% of cases (P = 0.06). The PS-ACST group had a larger hernia defect size (374.9 ± 156.4 versus 223.7±119.7 cm2, P < 0.01) and increased intraoperative time (242.1 ± 63.8 versus 209.5 ± 71.0 min, P < 0.01). Despite the larger defect size, the mesh size was comparable (1096.0 ± 535.6 versus 944.4 ± 391.5, P = 0.71). Biologic mesh was more frequently utilized in PS-ACS patients (51.4% versus 27.3%, P = 0.03). All PS-ACST patients had a bilateral CST compared with 72.7% who received a TAR (P < 0.01). The fascial defect was fully closed in all but two cases (94.6% versus 100.0%, P = 0.16). Placement of an incisional vacuum-assisted closure device occurred more frequently in the PS-ACST group (32.4% versus 14.5%, P < 0.01). The overall wound complication rate was not significantly different (16.2% versus 20.0%, P = 0.79), neither was superficial dehiscence (5.7% versus 5.7%, P = 1.00), deep wound infection (5.7% versus 9.5%, P = 0.70), or seroma requiring reintervention (5.4% versus 5.5%, P = 0.99). There were no patients in the PS-ACST who required return to the operating room for wound-related issues (0.0% versus 9.6%, P = 0.08), and requirement for a percutaneous drain was uncommon (2.9% versus 7.7%, P = 0.64). Length of stay was one and a half days longer for PS-ACST patients (8.9 ± 5.4 versus 7.3 ± 4.0 days, P = 0.04), but 30-day readmissions were no different (5.4% versus 10.9%, P = 0.47). Using logistic regression, none of the factors that were significantly different in the univariate analysis correlated with wound complications (P > 0.05). CONCLUSIONS: PS-ACST, despite being used for larger defects, had equivalent rates of wound complications and need for reintervention compared with patients undergoing TAR. REFERENCE: 1. Maloney SR, Schlosser KA, Prasad T, et al. Twelve years of component separation technique in abdominal wall reconstruction. Surgery (United States). 2019;166:435–444. doi:10.1016/j.surg.2019.05.043