Year-Over-Year Ventral Hernia Recurrence Rates and Risk Factors

Importance

Recurrence is one of the most challenging adverse events after ventral hernia repair as it impacts quality of life, utilization of resources, and subsequent need for re-repair. Rates of recurrence range from 30% to 80% after ventral hernia repair.

Objective

To determine the contemporary ventral hernia recurrence rate over time in patients with previous hernia repair and to determine risk factors associated with recurrence.

Design, Setting, and Participants

This retrospective, population-based study used the Abdominal Core Health Quality Collaborative registry to evaluate year-over-year recurrence rates in patients with prior ventral hernia repair between January 2012 and August 2022. Patients who underwent at least 1 prior ventral hernia repair were included and categorized into 2 groups based on mesh or no-mesh use. There were 43 960 eligible patients; after exclusion criteria (patients with concurrent inguinal hernias as the primary diagnosis, nonstandard hernia procedure categories, American Society of Anesthesiologists class unassigned, or no follow-up), 29 834 patients were analyzed in the mesh group and 5599 in the no-mesh group.

Main Outcomes and Measures

Ventral hernia recurrence rates. Risk factors analyzed include age, body mass index, sex, race, insurance type, medical comorbidities, American Society of Anesthesiologists class, smoking, indication for surgery, concomitant procedure, hernia procedure type, myofascial release, fascial closure, fixation type, number of prior repairs, hernia width, hernia length, mesh width, mesh length, operative approach, prior mesh placement, prior mesh infection, mesh location, mesh type, postoperative surgical site occurrence, postoperative surgical site infection, postoperative seroma, use of drains, and reoperation.

Results

Among 29 834 patients with mesh, the mean (SD) age was 57.17 (13.36) years, and 14 331 participants (48.0%) were female. Among 5599 patients without mesh, the mean (SD) age was 51.9 (15.31) years, and 2458 participants (43.9%) were female. When comparing year-over-year hernia recurrence rates in patients with and without prior mesh repair, respectively, the Kaplan Meier analysis showed a recurrence rate of 201 cumulative events with 13 872 at risk (2.8%) vs 104 cumulative events with 1707 at risk (4.0%) at 6 months; 411 cumulative events with 4732 at risk (8.0%) vs 184 cumulative events with 427 at risk (32.6%) at 1 year; 640 cumulative events with 1518 at risk (19.7%) vs 243 cumulative events with 146 at risk (52.4%) at 2 years; 731 cumulative events with 670 at risk (29.3%) vs 258 cumulative events with 73 at risk (61.4%) at 3 years; 777 cumulative events with 337 at risk (38.5%) vs 267 cumulative events with 29 at risk (71.2%) at 4 years; and 798 cumulative events with 171 at risk (44.9%) vs 269 cumulative events with 19 at risk (73.7%) at 5 years. Higher body mass index; immunosuppressants; incisional and parastomal hernias; a robotic approach; greater hernia width; use of a biologic or resorbable synthetic mesh; and complications, such as surgical site infections and reoperation, were associated with higher odds of hernia recurrence. Conversely, greater mesh width, myofascial release, and fascial closure had lower odds of recurrence. Hernia type was the most important variable associated with recurrence.

Conclusions and Relevance

In this study, the 5-year recurrence rate after ventral hernia repair was greater than 40% and 70% in patients with and without mesh, respectively. Rates of ventral hernia recurrence increased over time, underscoring the importance of close, long-term follow up in this population.

Evaluation of 30-day outcomes for open ventral hernia repair using self-gripping versus nonself-gripping mesh

BACKGROUND

The use of mesh is standard of care for large ventral hernias repaired on an elective basis. The most used type of mesh includes synthetic polypropylene mesh; however, there has been an increase in the usage of a new polyester self-gripping mesh, and there are limited data regarding its efficacy for ventral hernia. The purpose of the study is to determine whether there is a difference in surgical site occurrence (SSO), surgical site infection (SSI), surgical site occurrence requiring procedural intervention (SSOPI), and recurrence at 30 days after ventral hernia repair (VHR) using self-gripping (SGM) versus non-self-gripping mesh (NSGM).

METHODS

We performed a retrospective study from January 2014 to April 2022 using the Abdominal Core Health Quality Collaborative (ACHQC). We collected data on patients over 18 years of age who underwent elective open VHR using SGM or NSGM and whom had 30-day follow-up. Propensity matching was utilized to control for variables including hernia width, body mass index, age, ASA, and mesh location. Data were analyzed to identify differences in SSO, SSI, SSOPI, and recurrence at 30 days.

RESULTS

9038 patients were identified. After propensity matching, 1766 patients were included in the study population. Patients with SGM had similar demographic and clinical characteristics compared to NSGM. The mean hernia width to mesh width ratio was 8 cm:18 cm with NSGM and 7 cm:15 cm with SGM (p = 0.63). There was no difference in 30-day rates of recurrence, SSI or SSO. The rate of SSOPI was also found to be 5.4% in the nonself-gripping group compared to 3.1% in the self-gripping mesh group (p < .005). There was no difference in patient-reported outcomes at 30 days.

CONCLUSIONS

In patients undergoing ventral hernia repair with mesh, self-gripping mesh is a safe type of mesh to use. Use of self-gripping mesh may be associated with lower rates of SSOPI when compared to nonself-gripping mesh.

T-line Hernia Mesh Repairs of Large Umbilical Hernias: Technique and Short-term Outcomes

Background

The T-line hernia mesh is a synthetic, polypropylene mesh specifically designed to prevent anchor point failure by evenly distributing tension through mesh suture extensions. This case series illustrates the first clinical application of the T-line mesh for umbilical hernia repair (UHR).

Methods

This study is a retrospective, consecutive cases series of all adult patients presenting to a single surgeon with symptomatic umbilical hernia requiring surgical repair using the T-line hernia mesh. Patient demographics, surgical details, and 30-day postoperative complications were collected. Descriptive statistics were computed in Microsoft Excel (Redmond, Va.).

Results

Three patients presented for UHR. All three patients were obese with mean body mass index of 37.5 ± 6.6. Two patients were former smokers, and two had presented after hernia recurrence. The average defect size was 80.1 cm2 ± 94.0 cm2. Two patients had UHR with onlay mesh placement, whereas one had a transversus abdominus release followed by retrorectus mesh placement. The average mesh size was 192.3 cm2 ± 82.5 cm2. All three cases were classified as clean. There were no intraoperative complications. No patients experienced 30-day postoperative complications or recurrence.

Conclusions

We present a case series of three patients presenting with large, symptomatic umbilical hernias who underwent UHR with T-line hernia mesh reinforcement without short term complications or hernia recurrence at last follow-up.

Are Surgeons Going to Be Left Holding the Bag? Incisional Hernia Repair and Intra-Peritoneal Non-Absorbable Mesh Implant Complications

Ventral incisional hernias are common indications for elective repair and frequently complicated by recurrence. Surgical meshes, which may be synthetic, bio-synthetic, or biological, decrease recurrence and, resultingly, their use has become standard. While most patients are greatly benefited, mesh represents a permanently implanted foreign body. Mesh may be implanted within the intra-peritoneal, preperitoneal, retrorectus, inlay, or onlay anatomic positions. Meshes may be associated with complications that may be early or late and range from minor to severe. Long-term complications with intra-peritoneal synthetic mesh (IPSM) in apposition to the viscera are particularly at risk for adhesions and potential enteric fistula formation. The overall rate of such complications is difficult to appreciate due to poor long-term follow-up data, although it behooves surgeons to understand these risks as they are the ones who implant these devices. All surgeons need to be aware that meshes are commercial devices that are delivered into their operating room without scientific evidence of efficacy or even safety due to the unique regulatory practices that distinguish medical devices from medications. Thus, surgeons must continue to advocate for more stringent oversight and improved scientific evaluation to serve our patients properly and protect the patient-surgeon relationship as the only rationale long-term strategy to avoid ongoing complications.

A Review of Abdominal Meshes for Hernia Repair-Current Status and Emerging Solutions

Abdominal hernias are common issues in the clinical setting, burdening millions of patients worldwide. Associated with pain, decreased quality of life, and severe potential complications, abdominal wall hernias should be treated as soon as possible. Whether an open repair or laparoscopic surgical approach is tackled, mesh reinforcement is generally required to ensure a durable hernia repair. Over the years, numerous mesh products have been made available on the market and in clinical settings, yet each of the currently used meshes presents certain limitations that reflect on treatment outcomes. Thus, mesh development is still ongoing, and emerging solutions have reached various testing stages. In this regard, this paper aims to establish an up-to-date framework on abdominal meshes, briefly overviewing currently available solutions for hernia repair and discussing in detail the most recent advances in the field. Particularly, there are presented the developments in lightweight materials, meshes with improved attachment, antimicrobial fabrics, composite and hybrid textiles, and performant mesh designs, followed by a systematic review of recently completed clinical trials.

Outcomes of Abdominal Wall Reconstruction with a Bovine versus a Porcine Acellular Dermal Matrix: A Propensity Score-Matched Analysis

BACKGROUND

Abdominal wall reconstruction (AWR) is one of the most commonly performed procedures, yet large comparative studies comparing outcomes of AWR using bovine acellular dermal matrix (BADM) and porcine acellular dermal matrix (PADM) are lacking.

METHODS

In this retrospective cohort study of patients who underwent AWR from March of 2005 to June of 2019, the primary comparative outcome measure was hernia recurrence with BADM versus PADM. The secondary outcome was the incidence of surgical-site occurrence (SSO) and surgical-site infection. A propensity score matching approach was applied to compare the clinical outcomes between the two study groups.

RESULTS

The authors identified 725 patients who underwent AWR using BADM (50.5%) or PADM (49.5%). Their mean ± SD age was 59.8 ± 11.5 years, mean body mass index was 31.4 ± 6.7 kg/m 2 , and mean follow-up time was 42 ± 29 months. With propensity score matching, 219 matched pairs were identified. Hernia recurrence rates in BADM (11.4%) and PADM (13.7%) groups did not differ significantly ( P = 0.793). SSO (26.5% versus 29.2%; P = 0.518) and SSI (13.2% versus 11%; P = 0.456) rates did not differ significantly in the PADM and BADM groups, respectively. Conditional logistic regression model and marginal Cox proportional hazards regression model determined that type of acellular dermal matrix was not significantly associated with SSOs (adjusted OR, 1.11; 95% CI, 0.74 to 1.70; P = 0.589) or hernia recurrence (adjusted hazard ratio, 0.85; 95% CI, 0.50 to 1.42; P = 0.52).

CONCLUSIONS

Both BADMs and PADMs provide durable, long-term outcomes. The hernia recurrence and postoperative surgical complication rates were not significantly different between BADM and PADM.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Impact of combined component separation technique and shoelace repair on big medline abdominal wall defect

BACKGROUND

Closure of large anterior abdominal wall defects, regardless of their etiology, is challenging. There is no standardized information describing definitive management. Therefore, we conducted this study to illustrate our experience on large midline abdominal wall defect repair using an effective modified reconstructive technique.

METHODS

This retrospective study was conducted at Al Naqib Hospital in Aden/Yemen between 2012 and 2019. Twenty-six patients with large midline abdominal wall defects of various etiologies underwent surgical repair using a combination of shoelace repair and the component separation technique. The procedure involved bilateral longitudinal division of the anterior rectus sheet and creation of a posterior layer by approximation of the medial edges of the divided rectus sheet (shoelace abdominoplasty) and anterior external oblique muscle aponeurosis separation (component separation technique) to approximate the lateral edges of the divided rectus sheet and move the rectus muscles toward the midline for constructing the anterior abdominal wall layer. The posterior and anterior layers and bilateral separated sheets were covered with a polypropylene mesh in all patients, except in those who underwent emergency damage control surgery.

RESULTS

Four, one, and two patients developed seroma, skin necrosis and chronic pain, and post-surgical wound infection, respectively. No recurrent herniation was recorded during the median follow-up of 5 years.

CONCLUSION

This technique is effective in restoring the integrity of the abdominal wall in large midline abdominal wall defects and has an acceptable aesthetic appearance. In our study, minimal complications were reported, and no cases of recurrent hernias were diagnosed during follow-up.

A reliable and replicable test protocol for the mechanical evaluation of synthetic meshes

Despite the worldwide spread of surgical meshes in abdominal and inguinal surgery repair, the lack of specific standards for mechanical characterization of synthetic meshes, used in hernia repair and urogynecologic surgery, makes performance comparison between prostheses undoubtedly difficult. This consequently leads to the absence of acknowledged specifications about the mechanical requirements that synthetic meshes should achieve in order to avoid patient discomfort or hernia recurrences. The aim of this study is to provide a rigorous test protocol for the mechanical comparison between surgical meshes having the same intended use. The test protocol is composed of three quasi-static test methods: (1) ball burst test, (2) uniaxial tensile test, and (3) suture retention test. For each test, post-processing procedures are proposed to compute relevant mechanical parameters from the raw data. Some of the computed parameters, indeed, could be more suitable for comparison with physiological conditions (e.g., membrane strain and anisotropy), while others (e.g., uniaxial tension at rupture and suture retention strength) are reported as they provide useful mechanical information and could be convenient for comparisons between devices. The proposed test protocol was applied on 14 polypropylene meshes, 3 composite meshes, and 6 urogynecologic devices to verify its universal applicability towards meshes of different types and produced by various manufacturers, and its repeatability in terms of coefficient of variation. The test protocol resulted easily applicable to all the tested surgical meshes with intra-subject variability characterized by coefficient of variations settled around 0.05. Its use within other laboratories could allow the determination of the inter-subject variability assessing its repeatability among users of alternative universal testing machines.

Polyglactin 910 Meshes Coated with Sustained-Release Cannabigerol Varnish Inhibit Staphylococcus aureus Biofilm Formation and Macrophage Cytokine Secretion: An In Vitro Study

Synthetic surgical meshes are commonly used in abdominal wall reconstruction surgeries to strengthen a weak abdominal wall. Common mesh-related complications include local infection and inflammatory processes. Because cannabigerol (CBG) has both antibacterial and anti-inflammatory properties, we proposed that coating VICRYL (polyglactin 910) mesh with a sustained-release varnish (SRV) containing CBG would prevent these complications. We used an in vitro infection model with Staphylococcus aureus and an in vitro inflammation model of lipopolysaccharide (LPS)-stimulated macrophages. Meshes coated with either SRV-placebo or SRV-CBG were exposed daily to S. aureus in tryptic soy medium (TSB) or macrophage Dulbecco's modified eagle medium (DMEM). Bacterial growth and biofilm formation in the environment and on the meshes were assessed by changes in optical density, bacterial ATP content, metabolic activity, crystal violet staining, spinning disk confocal microscopy (SDCM), and high-resolution scanning electron microscopy (HR-SEM). The anti-inflammatory effect of the culture medium that was exposed daily to the coated meshes was analyzed by measuring the release of the cytokines IL-6 and IL-10 from LPS-stimulated RAW 264.7 macrophages with appropriate ELISA kits. Additionally, a cytotoxicity assay was performed on Vero epithelial cell lines. We observed that compared with SRV-placebo, the segments coated with SRV-CBG inhibited the bacterial growth of S. aureus in the mesh environment for 9 days by 86 ± 4% and prevented biofilm formation and metabolic activity in the surroundings for 9 days, with respective 70 ± 2% and 95 ± 0.2% reductions. The culture medium that was incubated with the SRV-CBG-coated mesh inhibited LPS-induced secretion of IL-6 and IL-10 from the RAW 264.7 macrophages for up to 6 days without affecting macrophage viability. A partial anti-inflammatory effect was also observed with SRV-placebo. The conditioned culture medium was not toxic to Vero epithelial cells, which had an IC₅₀ of 25 µg/mL for CBG. In conclusion, our data indicate a potential role of coating VICRYL mesh with SRV-CBG in preventing infection and inflammation in the initial period after surgery.

Characterization and modeling of the in-plane collagen fiber distribution in the porcine dermis

The structural arrangement of collagen fibers in the plane of the dermis layer plays a critical role in accurately predicting the mechanical behavior of skin tissues. This paper combines a histological analysis with statistical modeling to characterize and model the in-plane collagen fiber distribution in the porcine dermis. The histology data reveals that the fiber distribution in the plane of the porcine dermis is non-symmetric. The histology data forms the basis of our model, which employs a combination of two π-periodic von-Mises distribution density functions to create a non-symmetric distribution. We demonstrate that a non-symmetric in-plane fiber distribution is a significant improvement over a symmetric distribution.

Outcomes of Complex Abdominal Wall Reconstruction After Oncologic Resection: 14-Year Experience at an NCI-Designated Cancer Center

BACKGROUND

Outcomes studies for abdominal wall reconstruction (AWR) in the setting of previous oncologic extirpation are lacking. We sought to evaluate long-term outcomes of AWR using acellular dermal matrix (ADM) after extirpative resection, compare them to primary herniorrhaphy, and report the rates and predictors of postoperative complications.

METHODS

We conducted a retrospective cohort study of patients who underwent AWR after oncologic resection from March 2005 to June 2019 at a tertiary cancer center. The primary outcome was hernia recurrence (HR). Secondary outcomes included surgical site occurrences (SSOs), surgical site infection (SSIs), length of hospital stay (LOS), reoperation, and 30-day readmission.

RESULTS

Of 720 consecutive patients who underwent AWR during the study period, 194 (26.9%) underwent AWR following resection of abdominal wall tumors. In adjusted analyses, patients who had AWR after extirpative resection were more likely to have longer LOS (β, 2.57; 95%CI, 1.27 to 3.86, p < 0.001) than those with primary herniorrhaphy, but the risk of HR, SSO, SSI, 30-day readmission, and reoperation did not differ significantly. In the extirpative cohort, obesity (Hazard ratio, 6.48; p = 0.003), and bridged repair (Hazard ratio, 3.50; p = 0.004) were predictors of HR. Radiotherapy (OR, 2.23; p = 0.017) and diabetes mellites (OR, 3.70; p = 0.005) were predictors of SSOs. Defect width (OR, 2.30; p < 0.001) and mesh length (OR, 3.32; p = 0.046) were predictors of SSIs. Concomitant intra-abdominal surgery for active disease was not associated with worse outcomes.

CONCLUSIONS

AWR with ADM following extirpative resection demonstrated outcomes comparable with primary herniorrhaphy. Preoperative risk assessment and optimization are imperative for improving outcomes.

Collagen Deposition and Inflammatory Response Associated with Macroporous Mesh Shrinkage in Incisional Hernia Repair: A Rat Model

Background: Mesh repair is the current recommendation for the treatment of incisional hernia; however, the best mesh has yet to be determined. The objective of this study was to compare the inflammatory response and collagen deposition in primary incisional hernia repair (P) and different macroporous mesh materials, including polypropylene with poliglecaprone (PP-PG), polyvinylidene fluoride (PVDF), and polyester (PE), using quantitative methods. Methods: Sixty male rats were divided into four groups. Anterior abdominal wall defects were created and either suture or mesh repair was done. Rats were euthanized on days 14, 90, and 180, and the gross findings were recorded. The inflammatory and collagen levels in the abdominal wall tissues were measured using enzyme-linked immunosorbent assay (ELISA). Results: The PE group demonstrated significant mesh shrinkage at 180 days. The extent of PE mesh shrinkage ranged from 22-42% (mean = 30.49%). At 14 days, the PVDF group had higher interleukin-6 (IL-6) levels than the PP-PG (P = .004) and PE groups (P = .019). At 90 days, the collagen type I (Col I) levels in the PE group were significantly lower than those in the others, and the collagen type I/III (Col I/III) ratios in the PE group were lower than those in the P group (P = .006). Conclusions: The persistently high IL-6 levels until 180 days and the decrease in Col I levels and Col I/III ratio at 90 days seem to predict mesh shrinkage at 180 days. The mesh induces high Col I levels, but those associated with low Col III levels should be preferred.

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.

New Insights into the Application of 3D-Printing Technology in Hernia Repair

Abdominal hernia repair using prosthetic materials is among the surgical interventions most widely performed worldwide. These materials, or meshes, are implanted to close the hernial defect, reinforcing the abdominal muscles and reestablishing mechanical functionality of the wall. Meshes for hernia repair are made of synthetic or biological materials exhibiting multiple shapes and configurations. Despite the myriad of devices currently marketed, the search for the ideal mesh continues as, thus far, no device offers optimal tissue repair and restored mechanical performance while minimizing postoperative complications. Additive manufacturing, or 3D-printing, has great potential for biomedical applications. Over the years, different biomaterials with advanced features have been successfully manufactured via 3D-printing for the repair of hard and soft tissues. This technological improvement is of high clinical relevance and paves the way to produce next-generation devices tailored to suit each individual patient. This review focuses on the state of the art and applications of 3D-printing technology for the manufacture of synthetic meshes. We highlight the latest approaches aimed at developing improved bioactive materials (e.g., optimizing antibacterial performance, drug release, or device opacity for contrast imaging). Challenges, limitations, and future perspectives are discussed, offering a comprehensive scenario for the applicability of 3D-printing in hernia repair.

A Prospective, Single Arm, Multi-Center Study Evaluating the Clinical Outcomes of Ventral Hernias Treated with OviTex® 1S Permanent Reinforced Tissue Matrix: The BRAVO Study 12-Month Analysis

BACKGROUND

Conflicting results from previous studies have led to dissent over whether surgical mesh is safe and effective in ventral hernia repair. A newer class of mesh known as a reinforced tissue matrix, combining a biologic scaffold and minimal polymer reinforcement, offers promise in reducing inflammatory response and increasing abdominal wall support. This study sought to assess the clinical utility of a reinforced tissue matrix (OviTex) in ventral hernia repair 12 months after implantation.

METHODS

This is a prospective, single-arm, multi-center study to evaluate the clinical performance of OviTex^® 1S Permanent (OviTex) in the repair of primary or recurrent ventral hernias (VH) in consecutive patients (ClinicalTrials.gov/NCT03074474). The rate of surgical site occurrences (SSOs) was evaluated 90 days post-surgery as the primary endpoint. Hernia recurrence and the incidence of postoperative events were evaluated between three and 12 months as secondary endpoints. The incidence of other complications and patient-reported outcomes were also recorded.

RESULTS

Ninety-two (92) patients were enrolled in the study, of whom seventy-six (76) reached the 12-month follow-up. All patients were at least 18 years of age with a BMI of <40 kg/m². Hernia defects were <20 × 20 cm, classified as class I-III according to the CDC wound classification system. Of the 76 patients who reached 12-month follow-up, twenty-six (34%) had previous VH repairs and thirteen (17%) had previous surgical infection. Sixty (79%) had factors known to increase the risk of recurrence. Twenty patients (26%) experienced SSOs, with ten (13%) requiring procedural intervention. Two of the 75 patients (2.7%) experienced a recurrence.

CONCLUSIONS

The low rate of hernia recurrence and SSOs requiring intervention illustrates the potential that reinforced tissue matrices, and OviTex 1S, in particular, have to improve outcomes in VH repairs. Follow-up to 24 months is ongoing.

The Effect of Adipose-Derived Stromal Vascular Fraction Cells to Abdominal Wall Fascia Defects in Rats: An Experimental Study

OBJECTIVE

Various synthetic and biological meshes have been developed to reduce recurrence and complications in ventral incisional hernia repairs. Adipose tissue is a rich reserve for mesenchymal stromal cells. In the present study we aimed to examine the effects of adipose-derived mesenchymal stromal cells (AD-MSCs) on abdominal incisional hernia repairs in rats.

MATERIALS AND METHODS

The study involved 32 male Wistar-Albino rats, weighing 200-250 g, which were divided into three groups. In Group 1 (control group) only an incisional hernia model was created. In Group 2, the incisional hernia model was created and 1 ml stromal vascular fraction (SVF), obtained from inguinal lipectomy material and containing mesenchymal stromal cells, was injected into the edges of the defect in the same session. In Group 3, only the incisional hernia model was created in the first stage and after 14 days, 1 ml of SVF was injected into the edges of the defect. Skin incisions of rats in Group 1 and 2 were opened on postoperative day 28 while in group 3 were opened on day 42. Peritoneal formation in abdominal wall defect was evaluated macroscopically and histopathologically.

RESULTS

Peritoneal formation was significantly superior in Groups 2 and 3 than in Group 1 (p: 0.031). In histopathological evaluation, the structural distortion and polymorphonuclear leukocyte (PMNL) levels were significantly higher in Group 1 than in Group 3 (p: 0.048 and p: 0.046, respectively). Granulation, capillary density, fibrosis and collagen organization were higher in Group 2 and 3, however this difference was not statistically significant (p > 0.05).

CONCLUSIONS

Adipose-derived stromal vascular fraction cells obtained from inguinal lipectomy material in rats positively affect the repair of abdominal incisional hernias by increasing peritoneal formation, and reducing structural distortion and PMNL infiltration.

Hydrogel-mesh composite for wound closure

During operations, surgical mesh is commonly fixed on tissues through fasteners such as sutures and staples. Attributes of surgical mesh include biocompatibility, flexibility, strength, and permeability, but sutures and staples may cause stress concentration and tissue damage. Here, we show that the functions of surgical mesh can be significantly broadened by developing a family of materials called hydrogel-mesh composites (HMCs). The HMCs retain all the attributes of surgical mesh and add one more: adhesion to tissues. We fabricate an HMC by soaking a surgical mesh with a precursor, and upon cure, the precursor forms a polymer network of a hydrogel, in macrotopological entanglement with the fibers of the surgical mesh. In a surgery, the HMC is pressed onto a tissue, and the polymers in the hydrogel form covalent bonds with the tissue. To demonstrate the concept, we use a poly(N-isopropylacrylamide) (PNIPAAm)/chitosan hydrogel and a polyethylene terephthalate (PET) surgical mesh. In the presence a bioconjugation agent, the chitosan and the tissue form covalent bonds, and the adhesion energy reaches above 100 J⋅m^-2 At body temperature, PNIPAAm becomes hydrophobic, so that the hydrogel does not swell and the adhesion is stable. Compared with sutured surgical mesh, the HMC distributes force over a large area. In vitro experiments are conducted to study the application of HMCs to wound closure, especially on tissues under high mechanical stress. The performance of HMCs on dynamic living tissues is further investigated in the surgery of a sheep.

Regulatory science for hernia mesh: Current status and future perspectives

Regulatory science for medical devices aims to develop new tools, standards and approaches to assess the safety, effectiveness, quality and performance of medical devices. In the field of biomaterials, hernia mesh is a class of implants that have been successfully translated to clinical applications. With a focus on hernia mesh and its regulatory science system, this paper collected and reviewed information on hernia mesh products and biomaterials in both Chinese and American markets. The current development of regulatory science for hernia mesh, including its regulations, standards, guidance documents and classification, and the scientific evaluation of its safety and effectiveness was first reported. Then the research prospect of regulatory science for hernia mesh was discussed. New methods for the preclinical animal study and new tools for the evaluation of the safety and effectiveness of hernia mesh, such as computational modeling, big data platform and evidence-based research, were assessed. By taking the regulatory science of hernia mesh as a case study, this review provided a research basis for developing a regulatory science system of implantable medical devices, furthering the systematic evaluation of the safety and effectiveness of medical devices for better regulatory decision-making. This was the first article reviewing the regulatory science of hernia mesh and biomaterial-based implants. It also proposed and explained the concepts of evidence-based regulatory science and technical review for the first time.

In-vitro Characterization of a Hernia Mesh Featuring a Nanostructured Coating

Abdominal hernia repair is a frequently performed surgical procedure worldwide. Currently, the use of polypropylene (PP) surgical meshes for the repair of abdominal hernias constitutes the primary surgical approach, being widely accepted as superior to primary suture repair. Surgical meshes act as a reinforcement for the weakened or damaged tissues and support tissue restoration. However, implanted meshes could suffer from poor integration with the surrounding tissues. In this context, the present study describes the preliminary evaluation of a PCL-Gel-based nanofibrous coating as an element to develop a multicomponent hernia mesh device (meshPCL-Gel) that could overcome this limitation thanks to the presence of a nanostructured biomimetic substrate for enhanced cell attachment and new tissue formation. Through the electrospinning technique, a commercial PP hernia mesh was coated with a nanofibrous membrane from a polycaprolactone (PCL) and gelatin (Gel) blend (PCL-Gel). Resulting PCL-Gel nanofibers were homogeneous and defect-free, with an average diameter of 0.15 ± 0.04 μm. The presence of Gel decreased PCL hydrophobicity, so that membranes average water contact angle dropped from 138.9 ± 1.1° (PCL) to 99.9 ± 21.6°, while it slightly influenced mechanical properties, which remained comparable to those of PCL (E = 15.7 ± 2.7 MPa, σ R = 7.7 ± 0.6 ε R = 118.8 ± 13.2%). Hydrolytic and enzymatic degradation was conducted on PCL-Gel up to 28 days, with maximum weight losses around 20 and 40%, respectively. The meshPCL-Gel device was obtained with few simple steps, with no influences on the original mechanical properties of the bare mesh, and good stability under physiological conditions. The biocompatibility of meshPCL-Gel was assessed by culturing BJ human fibroblasts on the device, up to 7 days. After 24 h, cells adhered to the nanofibrous substrate, and after 72 h their metabolic activity was about 70% with respect to control cells. The absence of detectable lactate dehydrogenase in the culture medium indicated that no necrosis induction occurred. Hence, the developed nanostructured coating provided the meshPCL-Gel device with chemical and topographical cues similar to the native extracellular matrix ones, that could be exploited for enhancing the biological response and, consequently, mesh integration, in abdominal wall hernia repair.

Human Primary Dermal Fibroblasts Interacting with 3-Dimensional Matrices for Surgical Application Show Specific Growth and Gene Expression Programs

Several types of 3-dimensional (3D) biological matrices are employed for clinical and surgical applications, but few indications are available to guide surgeons in the choice among these materials. Here we compare the in vitro growth of human primary fibroblasts on different biological matrices commonly used for clinical and surgical applications and the activation of specific molecular pathways over 30 days of growth. Morphological analyses by Scanning Electron Microscopy and proliferation curves showed that fibroblasts have different ability to attach and proliferate on the different biological matrices. They activated similar gene expression programs, reducing the expression of collagen genes and myofibroblast differentiation markers compared to fibroblasts grown in 2D. However, differences among 3D matrices were observed in the expression of specific metalloproteinases and interleukin-6. Indeed, cell proliferation and expression of matrix degrading enzymes occur in the initial steps of interaction between fibroblast and the investigated meshes, whereas collagen and interleukin-6 expression appear to start later. The data reported here highlight features of fibroblasts grown on different 3D biological matrices and warrant further studies to understand how these findings may be used to help the clinicians choose the correct material for specific applications.

Chinese expert consensus on adult ventral abdominal wall defect repair and reconstruction

BACKGROUND

Surgical management of patients with ventral abdominal wall defects, especially complex abdominal wall defects, remains a challenging problem for abdominal wall reconstructive surgeons. Effective surgical treatment requires appropriate preoperative assessment, surgical planning, and correct operative procedure in order to improve postoperative clinical outcomes and minimize complications. Although substantial advances have been made in surgical techniques and prosthetic technologies, there is still insufficient high-level evidence favoring a specific technique. Broad variability in existing practice patterns, including clinical pre-operative evaluation, surgical techniques and surgical procedure selection, are still common.

DATA SOURCES

With the purpose of providing a best practice algorithm, a comprehensive search was conducted in Medline and PubMed. Sixty-four surgeons considered as experts on abdominal wall defect repair and reconstruction in China were solicited to develop a Chinese consensus and give recommendations to help surgeons standardize their techniques and improve clinical results.

CONCLUSIONS

This consensus serves as a starting point to provide recommendations for adult ventral abdominal wall repair and reconstruction in China and may help build opportunities for international cooperation to refine AWR practice.

Development of Biocomposite Polymeric Systems Loaded with Antibacterial Nanoparticles for the Coating of Polypropylene Biomaterials

The development of a biocomposite polymeric system for the antibacterial coating of polypropylene mesh materials for hernia repair is reported. Coatings were constituted by a film of chitosan containing randomly dispersed poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles loaded with chlorhexidine or rifampicin. The chlorhexidine-loaded system exhibited a burst release during the first day reaching the release of the loaded drug in three or four days, whereas rifampicin was gradually released for at least 11 days. Both antibacterial coated meshes were highly active against Staphylococcus aureus and Staphylococcus epidermidis (10⁶ CFU/mL), displaying zones of inhibition that lasted for 7 days (chlorhexidine) or 14 days (rifampicin). Apparently, both systems inhibited bacterial growth in the surrounding environment, as well as avoided bacterial adhesion to the mesh surface. These polymeric coatings loaded with biodegradable nanoparticles containing antimicrobials effectively precluded bacterial colonization of the biomaterial. Both biocomposites showed adequate performance and thus could have potential application in the design of antimicrobial coatings for the prophylactic coating of polypropylene materials for hernia repair.

Clinically available reinforcing materials for soft tissue reconstruction

Navigating the rapidly evolving field of materials for soft tissue reinforcement is challenging given the volume of clinically available options. Additionally, the current generally accepted classifications of these mesh materials confound the understanding of their utility by grouping disparate materials that have attributes overlapping category boundaries and that do not fully consider their clinically functionality. This review article highlights, from a materials science perspective, the most important attributes of these materials to improve the clinical decision-making process in the selection of the most appropriate features and design for the patient, surgery and clinical need. These characteristics include the physical attributes that directly impact the surgical procedure and immediate postoperative mechanical requirements as well as the post-implantation properties such as an adequate reinforcement time, strength of the resulting tissue and infection risk profile.

Design of a comparative outcome analysis of open, laparoscopic, or robotic-assisted incisional or inguinal hernia repair utilizing surgeon experience and a novel follow-up model

BACKGROUND

In a recent publication, the International Guidelines for Groin Hernia Management by the European Hernia Society (EHS) recognized the need to individualize and tailor the surgical approach for hernia repair. There may be different opportunities for optimization of the surgical technique for surgeons performing open, laparoscopic, or robotic-assisted hernia repair. Robotic-assisted hernia repair is a relatively new minimally invasive surgical approach compared to laparoscopic and open repair. Currently, there is a lack of comparative prospective studies designed to evaluate long-term outcomes of patients undergoing robotic-assisted, laparoscopic, or open hernia repair.

MATERIALS & METHODS

This manuscript presents an innovative study design with two study cohorts (incisional and inguinal hernia repair) that contain three arms (robotic-assisted, laparoscopic, and open). The trial objective is to collect short-term and long-term outcomes for patients undergoing robotic-assisted, laparoscopic, or open hernia repair. The present publication will discuss the trial design, methods used to ensure consistency in surgeon expertise, and provides strategies to obtain long-term (> 3 months) follow-up data for enrolled patients.

RESULTS

One hundred subjects underwent incisional and one hundred underwent inguinal hernia repair at the time of this manuscript. Surgeon experience was analyzed across the three surgical techniques and follow-up compliance was assessed through 1 year. The follow-up completion rates for both study cohorts were >80% for all visits.

CONCLUSIONS

The innovative trial design helped to improve the quality and quantity of long-term follow-up. More innovative options to improve patient retention may be tested in future trials of similar design.

Understanding the Extracellular Matrix to Enhance Stem Cell-Based Tissue Regeneration

The extracellular matrix is a biologically critical entity that has historically been poorly understood. Here we discuss how new tools for characterizing matrix composition and function enable us to design and deliver advanced matrices in vitro, to optimize regeneration, and in vivo, within a variety of tissues and organs.

Adhesions on polypropylene versus Sepramesh® meshes: an experimental study in rats

OBJECTIVE

to compare the formation of induced intraperitoneal adhesions in rats when using polypropylene and Sepramesh® meshes.

METHODS

we used 20 male Wistar rats, randomly grouped in two groups of ten animals each. We arranged two 10x20mm meshes intraperitoneally into each animal, one being the polypropylene (PP), and the other, Sepramesh®. In Group 1, the polypropylene mesh was positioned to the right, and the Sepramesh®, to the left. In Group 2, the meshes' layout was reversed. After 14 days of the procedure, we euthanized the animals and analyzed the incorporation and percentages of adhesions macroscopically in each mesh. We submitted the collected data to statistical analysis with a significance level of 5% (p<0.05).

RESULTS

all meshes showed adhesions. In the Sepramesh® ones, the percentage of surface covered by adhesions ranged from 2% to 86%, with a mean of 18.6±18.6%, while in the polypropylene meshes, it varied between 6% and 86%, with an average of 57.4%±34.9% (p<0.05). The preferred adhesion sites on both meshes were the edges.

CONCLUSION

although no mesh was able to completely inhibit the development of adhesions, the Sepramesh® mesh presented less adhesions to the polypropylene mesh. The most common sites of adhesion formation were the edges of the prosthesis, which evidences the importance of the adequate fixation of the meshes.

Sirolimus-coated, poly(L-lactic acid)-modified polypropylene mesh with minimal intra-peritoneal adhesion formation in a rat model

PURPOSE

This study evaluated the manufacturing method and anti-adhesion properties of a new composite mesh in the rat model, which was made from sirolimus (SRL) grafts on a poly(L-lactic acid) (PLLA)-modified polypropylene (PP) hernia mesh.

METHODS

PLLA was first grafted onto argon-plasma-treated native PP mesh through catalysis of stannous chloride. SRL was grafted onto the surface of PP-PLLA meshes using catalysis of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 4-dimethylaminopyridine (DMAP) in a CH₂Cl₂ solvent. Sprague-Dawley female rats received either SRL-coated meshes, PP-PLLA meshes, or native PP meshes to repair abdominal wall defects. At different intervals, rats were euthanized by a lethal dose of chloral hydrate and adhesion area and tenacity were evaluated. Sections of the mesh with adjacent tissues were assessed histologically.

RESULTS

Attenuated total reflection Fourier transformed infrared (ATR-FTIR) spectroscopy indicated the existence of a C=O group absorption peak (1724.1 cm^-1), and scanning electron microscope morphological analysis indicated that the surface of the PP mesh was covered with SRL. Compared to the native PP meshes and PP-PLLA meshes, SRL-coated meshes demonstrated the greatest ability to decrease the formation of adhesions (P < 0.05) and inflammation.

CONCLUSIONS

The SRL-coated composite mesh showed minimal formation of intra-abdominal adhesions in a rat model of abdominal wall defect repair.

Comparison of mesh fixation devices for laparoscopic ventral hernia repair: an experimental study on human anatomic specimens

BACKGROUND

As there is a lack of clarity in terms of the tensile strength of mesh fixation for laparoscopic ventral hernia repair (LVHR), our aim was to investigate the immediate tensile strength of currently available mesh fixation devices on human anatomic specimens.

METHODS

Sixteen recently deceased body donators (mean body mass index of 24.4 kg/m²) were used to test the immediate tensile strength (Newton) of 11 different LVHR mesh fixation devices.

RESULTS

Each of the 11 different laparoscopic fixation devices was tested 44 times. Non-articulating tackers provided higher fixation resistance to tensile stress in comparison to articulating tackers (5.1-mm ReliaTack™: 16.9 ± 8.7 N vs. 12.2 ± 5.6 N, p = 0.013; 7-mm ReliaTack™: 19.8 ± 9.4 N vs. 15.0 ± 7.0 N, p = 0.007). Absorbable tacks with a greater length, i.e. ≥6 mm (7-mm ReliaTack™, 6-mm SorbaFix™ and 7.2-mm SecureStrap™) had significantly higher fixation tensile strength than tacks with a shorter length, i.e. < 6 mm (5.1-mm ReliaTack™ and 5.1-mm AbsorbaTack™) (p < 0.001). Furthermore, transfascial sutures (PDS 2-0 sutures 26.3 ± 5.6 N) provided superior fixation tensile strength than 5.1-mm AbsorbaTack™ (13.6 ± 7.3 N) and cyanoacrylate glues such as LiquiBand FIX8™ (3.5 ± 2.4 N) (p < 0.001, respectively). There was a significant deterioration in fixation capacity in obese body donators with a body mass index > 30 kg/m² (13.8 ± 8.0 vs. 17.9 ± 9.7 N, p = 0.044).

CONCLUSIONS

Although articulating laparoscopic tackers improve accessibility and facilitate the utilization of tacks within the fixation weak spot adjacent to the trocar placement, an articulating shaft that is not ergonomic to use may limit mechanisms of force transmission. For mesh fixation in LVHR, transfascial sutures and tacks with a longer length provide better immediate fixation tensile strength results.

A Simple Modification Method to Obtain Anisotropic and Porous 3D Microfibrillar Scaffolds for Surgical and Biomedical Applications

In native tissues, cellular organization is predominantly anisotropic. Yet, it remains a challenge to engineer anisotropic scaffolds that promote anisotropic cellular organization at macroscopic length scales. To overcome this challenge, an innovative, cheap and easy method to align clinically approved non-woven surgical microfibrillar scaffolds is presented. The method involves a three-step process of coating, unidirectional stretching of scaffolds after heating them above glass transition temperature, and cooling back to room temperature. Briefly, a polymer coating is applied to a non-woven mesh that results in a partial welding of randomly oriented microfibers at their intersection points. The coated scaffold is then heated above the glass transition temperature of the coating and the scaffold polymer. Subsequently, the coated scaffold is stretched to produce aligned and three dimentional (3D) porous fibrillar scaffolds. In a proof of concept study, a polyglycolic acid (PGA) micro-fibrillar scaffold was coated with poly(4-hydroxybutirate) (P4HB) acid and subsequently aligned. Fibroblasts were cultured in vitro within the scaffold and results showed an increase in cellular alignment along the direction of the PGA fibers. This method can be scaled up easily for industrial production of polymeric meshes or directly applied to small pieces of scaffolds at the point of care.