A review of the composition, characteristics, and effectiveness of barrier mesh prostheses utilized for laparoscopic ventral hernia repair

Standardization of laparoscopic intraperitoneal onlay mesh repair for incisional hernia: Impact on clinical outcome and quality-of-life (LIPOM trial, NCT 02089958)

Purpose

Current available outcome data following laparoscopic intraperitoneal onlay mesh repair (IPOM) for incisional hernia (IH) are comparable to a limited extent only because of a huge number of variability particulary in surgical technique and use of medical devices. In this prospective observational multicenter cohort study we evaluate the impact of a consensus driven standard protocol for IPOM, that is mesh fixation with absorbable tacks in double crown technique enforced by additional non-absorbable transfascial sutures at the edges of the mesh along with the use of Physiomesh™, on clinical and patient reported outcome measures.

Methods

A total of 102 consecutive patients were screened for eligibility between September 2013 and October 2014. 85 patients (IH: EHS W1: n = 39, W2: n = 46) were included into the study. Clinical examination and PROM for pain and quality of life measure (Carolina Comfort Scale, CCS) were performed at baseline, during hospital stay and at 6 weeks, 6 months and 1 year follow-up.

Results

The follow-up rate was 87,1 % for the primary endpoint. The Kaplan-Meier estimate for freedom-of-recurrence at 1 year was 95.9 % (95 %-CI: 87.9-98.7 %), the cumulative recurrence rate at 1 year was 4.1 % (95 %-CI: 0.9-11.7 %). There was no intraoperative complication. One seroma (type I; 1/84 (1,2 %), 95 %-CI: 0-7.1 %) was diagnosed during hospital stay. 12 seroma (n = 12/74 (16,2 %), 95 %-CI: 9.4-26.4 %; n = 10 type II and n = 2 type IV) were diagnosed during follow-up requiring surgical intervention in 1 patient (1,4 %, Clavien Dindo grade IIIb). Subcutaneous hematoma were found during follow-up in 8 patients (8/75 (10.7 %); 95 %-CI: 5.3-19.9) with need for surgical intervention in 2 patients (2,7 %, Clavien Dindo grade IIIb). There were 3 superficial surgical site infections (3/74 (4,1 %); 95 %-CI: 0.9-11.7 %, Clavien-Dindo grade I) without need for reoperation. Patient reported pain as measured by numeric rating scale at baseline was 1.36 ± 1.53 and 0.35 ± 1.04 at 1 year follow-up. CCS total scores indicated a good outcome with a decrease to 2.80 ± 6.47 (Min: 0, Q1: 0, Median: 0; Q3: 3.0; Max: 38.0) at 1 year follow-up. Subscore sensation of mesh decreased from 4.01 ± 6.76 (min: 0, Q1: 0, Median: 0; Q3: 5.0; Max: 28.0) at 6 weeks to 1.67 ± 3.99 (Min: 0, Q1: 0, Median: 0; Q3: 1.0; Max: 21.0) after 6 months and 0.90 ± 2.69 (Min: 0, Q1: 0, Median: 0; Q3: 0; Max: 14.0) after 1 year follow-up. Subscores pain and movement limitation both decreased during follow-up and were significantly reduced at 1 year compared to preoperative assessment (p < 0.001).

Conclusions

This study showed favourable clinical and patient reported outcomes and a low rate of recurrences at 1 year follow-up after IPOM for elective IH applying a standardized surgical technique including the use of Physiomesh™. In view of the data leading to the market withdrawal of the Physiomesh™, one might conclude, that the described standard may have contributed to a compensation of the suspected delay in tissue integration of the Physiomesh™ resulting in a more proper mesh fixation compared to absorbable tack fixation with/without absorbable TFS. This may lead to the general appraisal, that the fixation technique has to be adapted to the individual characteristics of type of mesh and fixation devices and the planned anatomic landing zone of the mesh.

Human Skeletal Muscle Myoblast Culture in Aligned Bacterial Nanocellulose and Commercial Matrices

Bacterial nanocellulose (BNC) is a durable, flexible, and dynamic biomaterial capable of serving a wide variety of fields, sectors, and applications within biotechnology, healthcare, electronics, agriculture, fashion, and others. BNC is produced spontaneously in carbohydrate-rich bacterial culture media, forming a cellulosic pellicle via a nanonetwork of fibrils extruded from certain genera. Herein, we demonstrate engineering BNC-based scaffolds with tunable physical and mechanical properties through postprocessing. Human skeletal muscle myoblasts (HSMMs) were cultured on these scaffolds, and in vitro electrical stimulation was applied to promote cellular function for tissue engineering applications. We compared physiologic maturation markers of human skeletal muscle myoblast development using a 2.5-dimensional culture paradigm in fabricated BNC scaffolds, compared to two-dimensional (2D) controls. We demonstrate that the culture of human skeletal muscle myoblasts on BNC scaffolds developed under electrical stimulation produced highly aligned, physiologic morphology of human skeletal muscle myofibers compared to unstimulated BNC and standard 2D culture. Furthermore, we compared an array of metrics to assess the BNC scaffold in a rigorous head-to-head study with commercially available, clinically approved matrices, Kerecis Omega3 Wound Matrix (Marigen) and Phoenix as well as a gelatin methacryloyl (GelMA) hydrogel. The BNC scaffold outcompeted industry standard matrices as well as a 20% GelMA hydrogel in durability and sustained the support of human skeletal muscle myoblasts in vitro. This work offers a robust demonstration of BNC scaffold cytocompatibility with human skeletal muscle cells and sets the basis for future work in healthcare, bioengineering, and medical implant technological development.

Combined use of composite mesh and acellular dermal matrix graft for abdominal wall repair following tumour resection

BACKGROUND

Surgeries for sarcomas in the abdominal wall require wide resections, often radical en bloc resections, which generate major defects involving a very complex repair. The combined use of porcine dermal xenografts, together with composite meshes, may assist in the repair of these defects with minimal complications.

METHOD

We present a series of 19 patients (10 males and 9 females), with a mean age of 53.2 years (range: 11-86 years) treated in the Sarcoma Unit of the Virgen de la Arrixaca University Hospital from January 2015 to December 2021. Histopathologically, there were four chondrosarcomas (21%), three Ewing sarcomas (15.7%), two desmoid tumours (10.5%), two undifferentiated pleomorphic sarcomas (10.5%), two well-differentiated liposarcomas (10.5%), two leiomyosarcomas (10.5%), one synovial sarcoma, one dermatofibrosarcoma protuberans, one fibromyxoid sarcoma (or Evans tumour), and one metastasis from an adenocarcinoma of unknown origin. All the patients were resected following surgical oncology principles and reconstructed by means of the combined use of a composite mesh acting as a neoperitoneum and a porcine dermal xenograft acting as an abdominal neofascia.

RESULTS

The mean size of the defects generated after surgery for tumour excision was 262.8 cm2 (range: 150-600 cm2). After a mean follow-up of 38 months, six patients (31.5%) developed complications-two cases of wound dehiscence, one case of surgical wound infection, one case of graft partial necrosis, one case of anastomotic leak and one death due to multiorgan failure secondary to massive bronchoaspiration.

CONCLUSION

Surgeries for sarcomas of the abdominal wall require wide oncological resections, which generate major abdominal wall defects. The repair of these defects by means of the combined use of synthetic and biological meshes is a technique associated with minimal complications and excellent medium-term results.

Comparison of Medical Research Abstracts Written by Surgical Trainees and Senior Surgeons or Generated by Large Language Models

Importance

Artificial intelligence (AI) has permeated academia, especially OpenAI Chat Generative Pretrained Transformer (ChatGPT), a large language model. However, little has been reported on its use in medical research.

Objective

To assess a chatbot's capability to generate and grade medical research abstracts.

Design, Setting, and Participants

In this cross-sectional study, ChatGPT versions 3.5 and 4.0 (referred to as chatbot 1 and chatbot 2) were coached to generate 10 abstracts by providing background literature, prompts, analyzed data for each topic, and 10 previously presented, unassociated abstracts to serve as models. The study was conducted between August 2023 and February 2024 (including data analysis).

Exposure

Abstract versions utilizing the same topic and data were written by a surgical trainee or a senior physician or generated by chatbot 1 and chatbot 2 for comparison. The 10 training abstracts were written by 8 surgical residents or fellows, edited by the same senior surgeon, at a high-volume hospital in the Southeastern US with an emphasis on outcomes-based research. Abstract comparison was then based on 10 abstracts written by 5 surgical trainees within the first 6 months of their research year, edited by the same senior author.

Main Outcomes and Measures

The primary outcome measurements were the abstract grades using 10- and 20-point scales and ranks (first to fourth). Abstract versions by chatbot 1, chatbot 2, junior residents, and the senior author were compared and judged by blinded surgeon-reviewers as well as both chatbot models. Five academic attending surgeons from Denmark, the UK, and the US, with extensive experience in surgical organizations, research, and abstract evaluation served as reviewers.

Results

Surgeon-reviewers were unable to differentiate between abstract versions. Each reviewer ranked an AI-generated version first at least once. Abstracts demonstrated no difference in their median (IQR) 10-point scores (resident, 7.0 [6.0-8.0]; senior author, 7.0 [6.0-8.0]; chatbot 1, 7.0 [6.0-8.0]; chatbot 2, 7.0 [6.0-8.0]; P = .61), 20-point scores (resident, 14.0 [12.0-7.0]; senior author, 15.0 [13.0-17.0]; chatbot 1, 14.0 [12.0-16.0]; chatbot 2, 14.0 [13.0-16.0]; P = .50), or rank (resident, 3.0 [1.0-4.0]; senior author, 2.0 [1.0-4.0]; chatbot 1, 3.0 [2.0-4.0]; chatbot 2, 2.0 [1.0-3.0]; P = .14). The abstract grades given by chatbot 1 were comparable to the surgeon-reviewers' grades. However, chatbot 2 graded more favorably than the surgeon-reviewers and chatbot 1. Median (IQR) chatbot 2-reviewer grades were higher than surgeon-reviewer grades of all 4 abstract versions (resident, 14.0 [12.0-17.0] vs 16.9 [16.0-17.5]; P = .02; senior author, 15.0 [13.0-17.0] vs 17.0 [16.5-18.0]; P = .03; chatbot 1, 14.0 [12.0-16.0] vs 17.8 [17.5-18.5]; P = .002; chatbot 2, 14.0 [13.0-16.0] vs 16.8 [14.5-18.0]; P = .04). When comparing the grades of the 2 chatbots, chatbot 2 gave higher median (IQR) grades for abstracts than chatbot 1 (resident, 14.0 [13.0-15.0] vs 16.9 [16.0-17.5]; P = .003; senior author, 13.5 [13.0-15.5] vs 17.0 [16.5-18.0]; P = .004; chatbot 1, 14.5 [13.0-15.0] vs 17.8 [17.5-18.5]; P = .003; chatbot 2, 14.0 [13.0-15.0] vs 16.8 [14.5-18.0]; P = .01).

Conclusions and Relevance

In this cross-sectional study, trained chatbots generated convincing medical abstracts, undifferentiable from resident or senior author drafts. Chatbot 1 graded abstracts similarly to surgeon-reviewers, while chatbot 2 was less stringent. These findings may assist surgeon-scientists in successfully implementing AI in medical research.

A prospective, multicenter trial of a long-term bioabsorbable mesh with Sepra technology in cohort of challenging laparoscopic ventral or incisional hernia repairs (ATLAS trial)

BACKGROUND

This prospective, multicenter, single-arm, open-label study evaluated P4HB-ST mesh in laparoscopic ventral or incisional hernia repair (LVIHR) in patients with Class I (clean) wounds at high risk for Surgical Site Occurrence (SSO).

METHODS

Primary endpoint was SSO requiring intervention <45 days. Secondary endpoints included: surgical procedure time, length of stay, SSO >45 days, hernia recurrence, device-related adverse events, reoperation, and Quality of Life at 1, 3, 6, 12, 18, and 24-months.

RESULTS

120 patients (52.5% male), mean age of 55.0 ± 14.9 years, and BMI of 33.2 ± 4.5 kg/m2 received P4HB-ST mesh. Patient-reported comorbid conditions included: obesity (86.7%), active smoker (45.0%), COPD (5.0%), diabetes (16.7%), immunosuppression (2.5%), coronary artery disease (7.5%), chronic corticosteroid use (2.5%), hypoalbuminemia (0.8%), advanced age (10.0%), and renal insufficiency (0.8%). Hernia types were primary ventral (44.2%), primary incisional (37.5%), recurrent ventral (5.8%), and recurrent incisional (12.5%). Patients underwent LVIHR in laparoscopic (55.8%) or robotic-assisted cases (44.2%), mean defect size 15.7 ± 28.3 cm2, mean procedure time 85.9 ± 43.0 min, and mean length of stay 1.0 ± 1.4 days. There were no SSOs requiring intervention beyond 45 days, n = 38 (31.7%) recurrences, n = 22 (18.3%) reoperations, and n = 2 (1.7%) device-related adverse events (excluding recurrence).

CONCLUSION

P4HB-ST mesh demonstrated low rates of SSO and device-related complications, with improved quality of life scores, and reoperation rate comparable to other published studies. Recurrence rate was higher than expected at 31.7%. However, when analyzed by hernia defect size, recurrence was disproportionately high in defects ≥7.1 cm2 (43.3%) compared to defects <7.1 cm2 (18.6%). Thus, in LVIHR, P4HB-ST may be better suited for small defects. Caution is warranted when utilizing P4HB-ST in laparoscopic IPOM repair of larger defects until additional studies can further investigate outcomes.

Polymer Hernia Repair Materials: Adapting to Patient Needs and Surgical Techniques

Biomaterials and their applications are perhaps among the most dynamic areas of research within the field of biomedicine. Any advance in this topic translates to an improved quality of life for recipient patients. One application of a biomaterial is the repair of an abdominal wall defect whether congenital or acquired. In the great majority of cases requiring surgery, the defect takes the form of a hernia. Over the past few years, biomaterials designed with this purpose in mind have been gradually evolving in parallel with new developments in the different surgical techniques. In consequence, the classic polymer prosthetic materials have been the starting point for structural modifications or new prototypes that have always strived to accommodate patients’ needs. This evolving process has pursued both improvements in the wound repair process depending on the implant interface in the host and in the material’s mechanical properties at the repair site. This last factor is important considering that this site—the abdominal wall—is a dynamic structure subjected to considerable mechanical demands. This review aims to provide a narrative overview of the different biomaterials that have been gradually introduced over the years, along with their modifications as new surgical techniques have unfolded.

Behaviour at the peritoneal interface of next-generation prosthetic materials for hernia repair

BACKGROUND

When using a prosthetic material in hernia repair, the behaviour of the mesh at the peritoneal interface is especially important for implant success. Biomaterials developed for their intraperitoneal placement are known as composites and are made up of two different-structure materials, one is responsible for good integration within host tissue and the other is responsible to make contact with the viscera. This study examines the behaviour at the peritoneal level of two composites, the fully degradable Phasix-ST® and the partially degradable Symbotex®. A polypropylene mesh (Optilene®) served as control.

METHODS

Sequential laparoscopy from 3 to 90 days, in a preclinical model in the New Zealand white rabbit, allowed monitoring adhesion formation. Morphological studies were performed to analyse the neoperitoneum formed in the repair process. Total macrophages were identified by immunohistochemical labelling. To identify the different macrophage phenotypes, complementary DNAs were amplified by qRT-PCR using specific primers for M1 (TNF-α/CXCL9) and M2 (MRC1/IL-10) macrophages.

RESULTS

The percentage of firm and integrated adhesions remained very high in the control group over time. Both composites showed a significant decrease in adhesions at all study times and in qualitative terms were mainly loose. Significant differences were also observed from 7 days onwards between the two composites, increasing the values in Phasix over time. Neoperitoneum thickness for Phasix was significantly greater than those of the other meshes, showing mature and organized neoformed connective tissue. Immunohistochemically, a significantly higher percentage of macrophages was observed in Symbotex. mRNA expression levels for the M2 repair-type macrophages were highest for Phasix but significant differences only emerged for IL-10.

CONCLUSIONS

Fewer adhesions formed to the Symbotex than Phasix implants. Ninety days after implant, total macrophage counts were significantly higher for Symbotex, yet Phasix showed the greater expression of M2 markers related to the tissue repair process.

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.

Nonthermal plasma treatment of polymers modulates biological fouling but can cause material embrittlement

Plasma-based treatment is a prevalent strategy to alter biological response and enhance biomaterial coating quality at the surfaces of biomedical devices and implants, especially polymeric materials. Plasma, an ionized gas, is often thought to have negligible effects on the bulk properties of prosthetic substrates given that it alters the surface chemistry on only the outermost few nanometers of material. However, no studies to date have systematically explored the effects of plasma exposure on both the surface and bulk properties of a biomaterial. This work examines the time-dependent effects of a nonthermal plasma on the surface and bulk (i.e. mechanical) properties of polymeric implants, specifically polypropylene surgical meshes and sutures. Findings suggest that plasma exposure improved resistance to fibrinogen adsorption and Escherichia coli attachment, and promoted mammalian fibroblast attachment, although increased duration of exposure resulted in a state of diminishing returns. At the same time, it was observed that plasma exposure can be detrimental to the material properties of individual filaments (i.e. sutures), as well as the structural characteristics of knitted meshes, with longer exposures resulting in further embrittlement and larger changes in anisotropic behavior. Though there are few guidelines regarding appropriate mechanical properties of surgical textiles, the results from this investigation imply that there are ultimate exposure limits for plasma-based treatments of polymeric implant materials when structural properties must be preserved, and that the effects of a plasma on a given biomaterial should be examined carefully before translation to a clinical scenario.

Postoperative ileus after laparoscopic primary and incisional abdominal hernia repair with intraperitoneal mesh (DynaMesh®-IPOM versus Parietex™ Composite): a single institution experience

PURPOSE

Laparoscopic primary or incisional abdominal hernia repair with intraperitoneal mesh placement is a well-accepted and safe technique. Evidence for complications however remains inconclusive, and little is known about the occurrence of postoperative ileus secondary to postoperative intra-abdominal adhesions with different types of IPOM meshes used. Therefore, we retrospectively compared the occurrence of postoperative ileus between two of the different meshes used in our center.

METHODS

Three hundred seventy-five patients who underwent ventral hernia repair with intraperitoneal mesh placement, either with a DynaMesh®-IPOM (FEG Textiltechnik mbH, Aachen, Nordrhein-Westfalen, Germany) or a Parietex™ Composite mesh (Medtronic, Minneapolis, MN, USA), at the Heilig-Hart Hospital in Lier (Antwerp, Belgium) between 2012 and 2017 were retrospectively compared with regard to the occurrence of postoperative ileus until 6 weeks postoperatively. Baseline demographics and clinical data up to 6 weeks postoperatively of the patients in the two mesh groups are provided.

RESULTS

The DynaMesh®-IPOM mesh group was associated with a significantly higher incidence of postoperative ileus compared with the Parietex™ Composite mesh group with a cutoff limit at postoperative day 1 (n = 17, 6.8% vs. n = 0, 0.0%; P = 0.003) and postoperative day 4 (n = 13, 5.2% vs. n = 0, 0.0%, P = 0.006), even with a mesh surface area of ≤ 300 cm² and when both meshes were fixated with the same method of fixation (Securestrap™) with a cutoff limit for postoperative ileus at postoperative day 1 (n = 4, 7.7% vs. n = 0, 0.0%; P = 0.013) and postoperative day 4 (n = 3, 5.8% vs. n = 0, 0.0%, P = 0.040). Of the 17 patients with a postoperative ileus, 9 (52.9%) had a suspicion of adhesive small bowel obstruction on CT scan (P = 0.033) with definitive confirmation of small bowel adhesions with the DynaMesh®-IPOM mesh at laparoscopy in 2 patients.

CONCLUSION

Our results confirm current literature available regarding postoperative ileus secondary to postoperative intra-abdominal adhesions with the DynaMesh®-IPOM mesh. However, further research with well-designed, multicenter randomized controlled studies to evaluate the use and related complications of these meshes is needed.

Retroprosthetic Seroma After Laparoscopic Ventral Hernia Repair Is Related to Mesh Used?

Purpose: Retroprosthetic seroma (RS) is defined as a fluid collection located between the abdominal viscera and the intraperitoneal mesh implanted during surgery. Aim of this study is to report the incidence and clinical impact of RS based on the type of mesh implanted during laparoscopic ventral hernia repair (LVHR). Materials and Methods: Patients who underwent LVHR were allocated in group A if expanded polytetrafluoroethylene (ePTFE) mesh was used during surgery and in group B if other types of mesh were used. Patients were evaluated on postoperative day (POD) 1 and 7 with physical examination and 1 month after surgery by physical examination and with an abdominal computed tomography scan, respectively. Results: Sixty patients were included. Of these 41 patients (68.3%) were included in group A and 19 patients (31.7%) in group B. Signs of RS were not observed in any patient on POD 7. One month after surgery, RS was observed in 13 patients (21.6%). One patient (7.7%) with RS experienced great discomfort and mesh detachment, and underwent a second surgical treatment. All RSs were observed in group A, and the difference with group B was statistically significant (P = .005). Conclusions: The use of ePTFE mesh is related to the development of RS. The treatment of choice without clinical symptoms should be conservative. Randomized control trial and prospective studies with a larger sample size and control group are required to confirm these data, although this study shows a high evidence of the relation of RS and the type of mesh.

Comparison of coated meshes for intraperitoneal placement in animal studies: a systematic review and meta-analysis

PURPOSE

Laparoscopic intraperitoneal onlay mesh in hernia repair can result in adhesions leading to intestinal obstruction and fistulation. The aim of this systematic review is to compare the effects of mesh coatings reducing the tissue-to-mesh adhesion in animal studies.

METHODS

Pubmed and Embase were systematically searched. Animal experiments comparing intraperitoneally placed meshes with coatings were eligible for inclusion. Only studies with comparable follow-up, measurements, and species were included for data pooling and subsequent meta-analysis.

RESULTS

A total of 131 articles met inclusion criteria, with four studies integrated into one comparison and five studies integrated into another comparison. Compared to uncoated polypropylene (PP) mesh, PP mesh coated with hyaluronic acid/carboxymethyl cellulose (HA/CMC) showed significantly reduced adhesion formation at follow-up of 4 weeks measured with adhesion score of extent (random effects model, mean difference,-  0.96, 95% CI - 1.32 to - 0.61, P < 0.001, I² = 23%; fixed effects model, mean difference,- 0.94, 95% CI - 1.25 to - 0.63, P < 0.001, I² = 23%). Compared to PP mesh, polyester mesh coated with collagen (PC mesh) showed no significant difference at follow-up of 4 weeks regarding percentage of adhesion-area on a mesh, using random effects model (mean difference - 11.69, 95% CI - 44.14 to 20.76, P = 0.48, I² = 92%). However, this result differed using fixed effects model (mean difference - 25.55, 95% CI - 33.70 to - 7.40, P < 0.001, I² = 92%).

CONCLUSION

HA/CMC coating reduces adhesion formation to PP mesh effectively at a follow-up of 4 weeks, while the anti-adhesive properties of PC mesh are inclusive comparing all study data.

The Importance of Registries in the Postmarketing Surveillance of Surgical Meshes

Objective:

To assess the role of registries in the postmarketing surveillance of surgical meshes.

Background:

To date, surgical meshes are classified as group II medical devices. Class II devices do not require premarket clearance by clinical studies. Ethicon initiated a voluntary market withdrawal of Physiomesh for laparoscopic use after an analysis of unpublished data from the 2 large independent hernia registries—Herniamed German Registry and Danish Hernia Database. This paper now presents the relevant data from the Herniamed Registry.

Methods:

The present analysis compares the prospective perioperative and 1-year follow-up data collected for all patients with incisional hernia who had undergone elective laparoscopic intraperitoneal onlay mesh repair either with Physiomesh (n = 1380) or with other meshes recommended in the guidelines (n = 3834).

Results:

Patients with Physiomesh repair had a markedly higher recurrence rate compared with the other recommended meshes (12.0% vs 5.0%; P < 0.001). In the multivariable analysis, the recurrence rate was highly significantly influenced by the mesh type used (P < 0.001). If Physiomesh was used, that led to a highly significant increase in the recurrence rate on 1-year follow-up (odds ratio 2.570, 95% CI 2.057, 3.210). The mesh type used also had a significant influence on chronic pain rates.

Conclusions:

The importance of real-world data for postmarketing surveillance of surgical meshes has been demonstrated in this registry-based study. Randomized controlled trials are needed for premarket approval of new devices. The role of sponsorship of device studies by the manufacturing company must be taken into account.

Comparative study of peritoneal adhesions after intraperitoneal implantation in rats of meshes of polypropylene versus polypropylene/polyglecaprone versus polyester/porcine collagen

PURPOSE

To Compare the extent and intensity of adhesions formed between the intra-abdominal organs and the intraperitoneal implants of polypropylene mesh versus polypropylene/polyglecaprone versus polyester/porcine collagen used for correction of abdominal wall defect in rats.

METHODS

After the defect in the abdominal wall, thirty Wistar rats were placed in three groups (ten animals each) for intraperitoneal mesh implant: polypropylene group, polypropylene/polyglecaprone group, and polyester/porcine collagen group. The macroscopic evaluation of the extent and intensity of adhesions was performed 21 days after the implant.

RESULTS

The polypropylene group had a higher statistically significant impairment due to visceral adhesions (p value = 0.002) and a higher degree of intense adherence in relation to polypropylene/polyglecaprone and polyester/porcine collagen groups (p value<0.001). The polyester/porcine collagen group showed more intense adhesions than the polypropylene/polyglecaprone group (p value=0.035).

CONCLUSIONS

The intraperitoneal implantation of polypropylene meshes to correct defects of the abdominal wall caused the appearance of extensive and firm adhesions to intra-abdominal structures. The use of polypropylene/polyglecaprone or polyester/porcine collagen tissue-separating meshes reduces the number and degree of adhesions formed.

Proof of concept, design, and manufacture via 3-D printing of a mesh with bactericidal capacity: Behaviour in vitro and in vivo

Currently, hernia treatment involves implantation of a mesh prosthesis, usually made of polypropylene, and the primary complication is infection of the device, which leads to an exponential increase in morbidity. Three-dimensional printing offers a method of dealing with complications of this magnitude. Therefore, in this study, the bactericidal properties and effectiveness of three-dimensional-printed meshes with polycaprolactone (PCL) and gentamicin were evaluated in vitro in Escherichia coli cultures, and their histological behaviour was examined in vivo. Different PCL meshes were implanted into four groups of rats, with 10 rats in each group: PCL meshes, PCL meshes with alginate and calcium chloride, PCL meshes with gentamicin, and PCL meshes with alginate and gentamicin. Thirty-six microporous meshes were manufactured, and their bactericidal properties were assessed. When the meshes did not include an antibiotic, an inhibition halo was not observed; when the gentamicin was free, an asymmetric inhibition area of 5.65 ± 0.46 cm² was present; when the gentamicin was encapsulated, a rectangular area of 5.40 ± 0.38 cm² was observed. In the rats, macroporous and microporous mesh implants produced mild inflammation and substantial fibrosis with collagen and neovascular foci. A significant difference was observed in fibroblastic activity between the PCL with alginate group and the PCL with alginate and gentamicin group microporous meshes (p = .013) and in collagen deposits between the macroporous and microporous meshes in the PCL mesh group (p = .033). The feasibility of manufacturing drug-doped printed PCL meshes containing alginate and gentamicin was verified, and the meshes exhibited bactericidal effects and good histopathological behaviour.

Open ventral hernia repair with a composite ventral patch - final results of a multicenter prospective study

Background

This study assessed clinical outcomes, including safety and recurrence, from the two-year follow-up of patients who underwent open ventral primary hernia repair with the use of the Parietex™ Composite Ventral Patch (PCO-VP).

Methods

A prospective single-arm, multicenter study of 126 patients undergoing open ventral hernia repair for umbilical and epigastric hernias with the PCO-VP was performed.

Results

One hundred twenty-six subjects (110 with umbilical hernia and 16 with epigastric hernia) with a mean hernia diameter of 1.8 cm (0.4–4.0) were treated with PCO-VP. One hundred subjects completed the two-year study. Cumulative hernia recurrence was 3.0% (3/101; 95%CI: 0.0–6.3%) within 24 months. Median Numeric Rating Scale pain scores improved from 2 [0–10] at baseline to 0 [0–3] at 1 month (P < 0.001) and remained low at 24 months 0 [0–6] (P < 0.001). 99% (102/103) of the patients were satisfied with their repair at 24 months postoperative.

Conclusions

The use of PCO-VP to repair primary umbilical and epigastric defects yielded a low recurrence rate, low postoperative and chronic pain, and high satisfaction ratings, confirming that PCO-VP is effective for small ventral hernia repair in the two-year term after implantation.

Trial registration

The study was registered publically at clinicaltrials.gov (NCT01848184 registered May 7, 2013).

Biomaterial Implants in Abdominal Wall Hernia Repair: A Review on the Importance of the Peritoneal Interface

Biomaterials have long been used to repair defects in the clinical setting, which has led to the development of a wide variety of new materials tailored to specific therapeutic purposes. The efficiency in the repair of the defect and the safety of the different materials employed are determined not only by the nature and structure of their components, but also by the anatomical site where they will be located. Biomaterial implantation into the abdominal cavity in the form of a surgical mesh, such as in the case of abdominal hernia repair, involves the contact between the foreign material and the peritoneum. This review summarizes the different biomaterials currently available in hernia mesh repair and provides insights into a series of peculiarities that must be addressed when designing the optimal mesh to be used in this interface.

New surgical meshes with patterned nanofiber mats

Abdominal wall hernia repair is one of the most common general surgeries nowadays. Surgical meshes used in hernia repair indeed improved the outcomes, but complications like chronic pain or hernia recurrence partly caused by mechanical mismatch cannot be ignored. This work designed six warp-knitted polypropylene (PP) meshes and found the properties of surgical meshes could be improved to better mimic the performances of human abdominal wall by designing meshes with appropriate textile structures. Poly-caprolactone was electrospun onto newly designed PP meshes and formed a thin layer of patterned nanofiber mat. The pattern of nanofiber mats was affected by the structure of meshes. Diverse nanofiber morphology (straight aligned, straight random or spiral random pattern) and fiber diameters (50–70 nm ultra-thin nanofibers or from 330 nm to 700 nm nanofibers) were observed in different regions of a single patterned nanofiber scaffold. The addition of electrospinning nanofibers enhanced cell adherence and proliferation as compared with naked PP meshes. Cell actin filaments spread along the nanofibers and formed a morphology exactly similar with the patterned mats on day 7. Furthermore, cells on thin and aligned patterned nanofibers showed much more elongation and better orientation than that of the spiral random fibers, suggesting that cell morphology can be altered by changing the patterns of scaffolds. This study helps us in further understanding the properties of hernia repair meshes with their textile structures and the biological interactions of cells with different substrates in order to develop new biomedical scaffolds with desired properties.

Newly designed warp-knitted meshes with different textile parameters and the interactions between cell and patterned nanofiber mats and different meshes.

Preclinical Evaluation of Mesh Implants: The Pathologist’s Perspective

Surgical and laparoscopic implantation of mesh devices is on the rise for a variety of applications. The complexity and range of evolving mesh designs calls for consistent and detailed pathologic evaluation in determining host responses and assessing overall safety. This review addresses the components of evaluation of mesh implants in animal models, with emphasis on histologic parameters, semiquantitative scoring matrices, and morphometric analyses that have been specifically adapted to this class of implants. Necropsy assessment should include implant persistence, architecture, and associated host responses such as exudation and adhesions. Microscopic evaluation should focus on primary relevant responses such as bioresorption, integration/tissue ingrowth, neovascularization, and inflammation. Selection of the best means of processing and evaluation can be complicated, as meshes may include one or more biologic components (e.g., collagen), synthetic polymer fibers, coatings, and other molecules. The architecture of some meshes can influence tissue responses and complicate sampling, sectioning, and evaluation. Recognition of specific study objectives and knowledge of anticipated responses helps to determine the appropriate histologic or immunochemical stains, while understanding of mesh composition and anticipated persistence in tissue determines the suitability of paraffin or resin embedding, and both guide the evaluation of mesh devices in the preclinical setting.

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.

Postoperative Abdominal Adhesions: Clinical Significance and Advances in Prevention and Management

Postoperative adhesions remain one of the more challenging issues in surgical practice. Although peritoneal adhesions occur after every abdominal operation, the density, time interval to develop symptoms, and clinical presentation are highly variable with no predictable patterns. Numerous studies have investigated the pathophysiology of postoperative adhesions both in vitro and in vivo. Factors such as type and location of adhesions, as well as timing and recurrence of adhesive obstruction remain unpredictable and poorly understood. Although the majority of postoperative adhesions are clinically silent, the consequences of adhesion formation can represent a lifelong problem including chronic abdominal pain, recurrent intestinal obstruction requiring multiple hospitalizations, and infertility. Moreover, adhesive disease can become a chronic medical condition with significant morbidity and no effective therapy. Despite recent advances in surgical techniques, there is no reliable strategy to manage postoperative adhesions. We herein review the pathophysiology and clinical significance of postoperative adhesions while highlighting current techniques of prevention and treatment.

Comparative study of Polypropylene versus Parietex composite®, Vicryl® and Ultrapro® meshes, regarding the formation of intraperitoneal adhesions

PURPOSE

To compare the polypropylene mesh (Marlex®) to Vicryl®, Parietex composite® and Ultrapro® meshes to assess the occurrence of adhesions in the intraperitoneal implantation.

METHODS

Sixty Wistar rats were allocated into three groups: PP+V, in which all the animals received a polypropylene and a Vicryl® mesh; PP+PC, with the implantation of polypropylene and Parietex composite® meshes and PP+UP, in which there was implantation of polypropylene and Ultrapro®. Macroscopic analysis was performed 28 days later to assess the percentage of mesh area affected by adhesion.

RESULTS

in the PP+ V group, the Vicryl® mesh showed lower adhesion formation (p=0.013). In the PP+PC, there were no differences between polypropylene and Parietex composite® (p=0.765). In the PP+UP group, Ultrapro® and polypropylene meshes were equivalent (p=0.198) .

CONCLUSION

All the four meshes led to adhesions, with the Vicryl® mesh showing the least potential for its formation.

A multicenter prospective study of patients undergoing open ventral hernia repair with intraperitoneal positioning using the monofilament polyester composite ventral patch: interim results of the PANACEA study

Purpose

This study assessed the recurrence rate and other safety and efficacy parameters following ventral hernia repair with a polyester composite prosthesis (Parietex™ Composite Ventral Patch [PCO-VP]).

Patients and methods

A single-arm, multicenter prospective study of 126 patients undergoing open ventral hernia repair with the PCO-VP was performed. Patient outcomes were assessed at discharge and at 10 days, 1, 6, 12, and 24 months postoperative.

Results

All patients had hernioplasty for umbilical (n = 110, 87.3%) or epigastric hernia (n = 16, 12.7%). Mean hernia diameter was 1.8 ± 0.8 cm. Mean operative time was 36.2 ±15.6 minutes, with a mean mesh positioning time of 8.1 ± 3.4 minutes. Surgeons reported satisfaction with mesh ease of use in 95% of surgeries. The cumulative hernia recurrence rate at 1 year was 2.8% (3/106). Numeric Rating Scale (NRS) pain scores showed improvement from 2.1 ± 2.0 at preoperative baseline to 0.5 ± 0.7 at 1 month postoperative (P < 0.001), and this low pain level was maintained at 12 months postsurgery (P < 0.001). The mean global Carolina’s Comfort Scale^® (CCS) score improved postoperatively from 3.8 ± 6.2 at 1 month to 1.6 ± 3.5 at 6 months (P < 0.001). One patient was unsatisfied with the procedure.

Conclusion

This 1-year interim analysis using PCO-VP for primary umbilical and epigastric defects shows promising results in terms of mesh ease of use, postoperative pain, and patient satisfaction. Recurrence rate is low, but, as laparoscopic evaluation shows a need for patch repositioning in some cases, an accurate surgical technique remains of utmost importance.

Critical overview of all available animal models for abdominal wall hernia research

PURPOSE

Since the introduction of the first prosthetic mesh for abdominal hernia repair, there has been a search for the "ideal mesh." The use of preclinical or animal models for assessment of necessary characteristics of new and existing meshes is an indispensable part of hernia research. Unfortunately, in our experience there is a lack of consensus among different research groups on which model to use. Therefore, we hypothesized that there is a lack of comparability within published animal research on hernia surgery due to wide range in experimental setup among different research groups.

METHODS

A systematic search of the literature was performed to provide a complete overview of all animal models published between 2000 and 2014. Relevant parameters on model characteristics and outcome measurement were scored on a standardized scoring sheet.

RESULTS

Due to the wide range in different animals used, ranging from large animal models like pigs to rodents, we decided to limit the study to 168 articles concerning rat models. Within these rat models, we found wide range of baseline animal characteristics, operation techniques, and outcome measurements. Making reliable comparison of results among these studies is impossible.

CONCLUSION

There is a lack of comparability among experimental hernia research, limiting the impact of this experimental research. We therefore propose the establishment of guidelines for experimental hernia research by the EHS.

The effect of thymoquinone coating on adhesive properties of polypropylene mesh

BACKGROUND

An incisional hernia is a common complication following abdominal surgery. Polypropylene mesh is frequently used in the repair of such defects and has nearly become the standard surgical treatment modality. Though they are very effective in reducing recurrence, mesh materials exhibit a strong stimulating effect for intraabdominal adhesion. The thymoquinone (TQ) extracted from Nigella sativa seeds has potential medical properties. TQ has anti-inflammatory, antioxidant and antibacterial properties. The aim of this study is to coat polypropylene mesh with TQ in order to investigate the effect of surface modification on intraabdominal adhesions.

METHODS

TQ-coated polypropylene mesh material was tested for cytotoxicity, contact angle, surface spectroscopy, TQ content, sterility, and electron microscopic surface properties. An experimental incisional hernia model was created in study groups, each consisting of 12 female Wistar rats. The defect was closed with uncoated mesh in control group, with polylactic acid (PLA) coated mesh and PLA-TQ coated mesh in study groups. Adhesion scores and histopathologic properties were evaluated after sacrifice on postoperative 21th day.

RESULTS

Granuloma formation, lymphocyte and polymorphonuclear leukocyte infiltration, histiocyte fibroblast and giant cell formation, capillary infiltration, collagen content were significantly reduced in the PLA-TQ coated mesh group (p < 0.05). Though not statistically significant, likely due to the limited number of study animals, adhesion formation was also reduced in the PLA-TQ coated mesh group (p: 0.067).

CONCLUSION

TQ coated mesh is shown to reduce adhesion formation and TQ is a promising coating material for mesh surface modification.

Repair of primary and incisional hernias using composite mesh fixed with absorbable tackers: preliminary experience of a laparoscopic approach with a newly designed mesh in 29 cases

Outcome of primary and incisional hernia repair is still affected by clinical complications in terms of recurrences, pain and discomfort. Factors like surgical approach, prosthesis characteristics and method of fixation might influence the outcome. We evaluated in a prospective observational study a cohort population which underwent primary and incisional laparoscopic hernia repair, with the use of a composite mesh in polypropylene fixed with absorbable devices. We focused on assessing the feasibility and safety of these procedures; they were always performed by an experienced laparoscopic surgeon, analyzing data from our patients through the EuraHS registry. Seventy nine procedures of primary and incisional hernia repair were performed from July 2013 to November 2015 at Santa Maria Regina degli Angeli Hospital in Adria (RO). All cases have been registered at the EuraHS registry ( http://www.eurahs.eu ); among them, we analyzed 29 procedures performed using a new composite polypropylene mesh (CMC, Clear Composite Mesh, DIPROMED srl San Mauro Torinese, Turin, Italy), fixed with absorbable tackers (ETHICON, Ethicon LLC Guaynabo, Puerto Rico 00969). We performed 23 incisional hernia repairs, 4 primary hernia repairs (1 umbilical, 2 epigastric and 1 lumbar hernia) and 2 parastomal hernia repairs. The median operation time was 65.1 min for elective and 81.4 min for urgent procedures (three cases). We had two post-operative complications (6.89%), one case of bleeding and another case of prolonged ileus successfully treated with conservative management. We had no recurrences at follow-up. According to QoL, at 12 months patients do not complain about any pain or discomfort for esthetic result. Laparoscopic treatment of primary and incisional hernia with the use of composite mesh in polypropylene fixed with absorbable devices is feasible and safe.

Evaluation of diaphragmatic mobility following intra-abdominal sub-diaphragmatic fixation of a double-layered mesh in rats

PURPOSE

To evaluate the tissue integration of a double-sided mesh after fixation in diaphragm and to study the diaphragmatic mobility by ultrasound.

METHODS

Twenty male Wistar rats were used. The animals were assigned into two equal groups according to the day of euthanasia. The animals were anesthetized and a 1.5 x 1.5 cm of double-layer mesh was inserted between the diaphragm and the liver. For the evaluation of the diaphragm mobility a sonographic method was used. Measurements on specific breathing parameters were taking place. Pathological evaluation took place after the animal's euthanasia.

RESULTS

Extra-hepatic granuloma was not differentiated overtime, (χ2=0.04, p>0.05). Neither fibrosis was significantly differentiated, (χ2=0.04, p>0.05). Intra-hepatic granuloma was significantly differentiated overtime, (χ2=10.21, p<0.05). Concerning Te parameter, means were significantly differentiated over time, F (3, 30) = 5.12, (p<0.01). Ttot parameter, it was differentiated over time, F (3, 8)=4.79, (p<0.05). IR parameter was also longitudinally differentiated, F (3, 30)=3.73, (p<0.05).

CONCLUSION

The measurements suggest a transient malfunction of diaphragmatic mobility despite the fact that inflammatory reaction, fibrosis and extra-hepatic granuloma were not significantly differentiated with the passage of time.

Parietex™ Composite mesh versus DynaMesh®-IPOM for laparoscopic incisional and ventral hernia repair: a retrospective cohort study

INTRODUCTION Laparoscopic incisional and ventral hernia repair (LIVHR) is widely accepted and safe but the type of mesh used is still debated. We retrospectively compared postoperative outcomes with two different meshes commonly used in LIVHR. METHODS This is a retrospective study of patients who underwent incisional hernia repair between January 2008 and December 2010. Two meshes were used: Parietex™ Composite (Covidien, New Haven, CT, USA) and the DynaMesh®-IPOM (FEG Textiltechnik mbH, Aachen, Germany). The two groups were compared with respect to recurrence rates, incidence of seroma and intestinal obstruction. RESULTS Among the 88 patients who underwent LIVHR, 75 patients (85.2%) presented with primary incisional hernia, 10 (11.4%) presented with a first recurrence and 3 (3.4%) presented with a second recurrence. Median follow-up was 53.6 months (range 40-61 months). 12.9% of patients had recurrence in the Parietex™ Composite mesh group (n=62) in comparison to 3.8% in the DynaMesh®-IPOM mesh group (n=26; P=0.20). DynaMesh®-IPOM was associated with a significantly higher incidence of intestinal obstruction secondary to adhesions (11.5% vs. 0%, P=0.006) and lower incidence of seroma and haematoma formation compared to Parietex™ composite mesh group (0% vs. 6.4% of patients; P=0.185). CONCLUSIONS LIVHR is a safe and feasible technique. Dynamesh®-IPOM is associated with a significantly higher incidence of adhesion related bowel obstruction, albeit with a lower incidence of recurrence, seroma and haematoma formation compared with Parietex™ Composite mesh. However, there is a need for further well-designed, multicentre randomised controlled studies to investigate the use of these meshes.

Formation of adhesion after intraperitoneal application of TiMesh: experimental study on a rodent model

BACKGROUND

After laparoscopic repair of an incisive hernia, intraperitoneal prosthetic mesh, as a foreign material, is a strong stimulus for the development of adhesion, which may be the cause of serious complications. This experimental study compared three different meshes and their ability to prevent the formation of adhesion and shrinkage.

METHODS

Ninety rats were divided randomly into three groups: in Group 1 Proceed mesh was implanted, in Group 2 Ultrapro mesh was implanted, and in Group 3 TiMesh was implanted. Mesh samples were fixed as an intraabdominal mesh in the upper part of the abdomen. Ten animals from each group were sacrificed on days 7, 28 and 60 post-surgery. After opening the abdomen, the formation of adhesion was assessed according to the Surgical Membrane Study Group (SMSG) score, the percentage of shrinkage of the mesh was established and inflammatory reaction scored.

RESULTS

The SMSG score for adhesion was statistically significantly higher on all the postoperative days in the Proceed and Ultrapro mesh groups than in the TiMesh group which caused milder inflammatory reaction on 60th day than others meshes. The size of the mesh after 7 days was statistically significantly smaller in the Proceed and Ultrapro groups than in the TiMesh group, but after 60 days it was statistically significantly larger than in the TiMesh group.

CONCLUSION

The least formation of adhesion was noted in the TiMesh group, in which the highest level of shrinkage was noticed after 28 and 60 days. TiMesh has advantages over the other meshes studied, but a larger size mesh may be recommended for intraperitoneal application.

Evaluation of a novel permanent capped helical coil fastener in a porcine model of laparoscopic ventral hernia repair

Background

Existing permanent helical coil fasteners, although commonly employed for mesh fixation during laparoscopic hernia repair, are associated with peritoneal tissue attachment formation and resultant visceral complications. We evaluated attachment formation, fastener engagement, and mesh/tissue integration associated with laparoscopic fixation using a novel permanent capped helical coil fastener (HC-Capped) compared to permanent non-capped helical coil fasteners (HC-Non-Capped) in a porcine model.

Methods

Twelve female pigs underwent bilateral laparoscopic intraperitoneal fixation of Composix™ L/P Mesh (10 × 15 cm oval) with HC-Capped or HC-Non-Capped fasteners. Thirty-two fasteners were used to secure each mesh utilizing a “double-crown” technique. Laparoscopy at 30 days was used to evaluate the presence and area coverage of attachments (Diamond Score) and percentage of engaged fasteners. At 90 days, following necropsy, each mesh was evaluated for the presence, percentage, and tenacity (Butler Score) of attachments and fastener engagement. Samples were biomechanically evaluated to assess tissue integration via T-peel testing.

Results

HC-Capped fasteners demonstrated a significantly lower attachment area score compared to the HC-Non-Capped group at 30 days (0.92 ± 0.26 vs. 2.50 ± 0.29/3.00, p = 0.002) and 90 days (0.60 ± 0.22 vs. 2.08 ± 0.29/3.00, p = 0.004). At 90 days, the HC-Capped group evidenced significantly lower attachment tenacity score (1.00 ± 0.37 vs. 2.75 ± 0.33/4.00, p = 0.013). Furthermore, at 30 and 90 days, a significantly greater percentage of HC-Capped fasteners remained properly engaged (30 days: 99.7 % vs. 86.5 %, p < 0.001 and 90 days: 99.4 % vs. 74.5 %, p = 0.001). T-peel biomechanical testing demonstrated significantly greater mesh/tissue integration for HC-Capped group (2.16 ± 0.24 vs. 1.16 ± 0.29 N/cm, p = 0.038).

Conclusions

In a porcine model, HC-Capped fasteners demonstrated significantly less attachment coverage and tenacity in the early postoperative period. Furthermore, the HC-Capped cohort evidenced significantly greater percentage of properly engaged fasteners and greater mesh/tissue integration. Data suggest that shielding exposed fastener points on the visceral mesh surface with polymer caps may reduce attachment formation and aid in mesh fixation and integration.

Inflammatory reaction to fish oil coated polypropylene mesh used for laparoscopic incisional hernia repair: a case report

Background

Polypropylene meshes are widely used in hernia repairs. Hernia meshes have been developed incorporating coatings of active agents. One commercially available mesh has a fish oil coating which is promoted as having anti-inflammatory properties. We report a case, a symptomatic foreign body granuloma reaction associated with a fish oil coated polypropylene mesh, which required eventual mesh explantation.

Case presentation

A 61-year old lady with previous peptic ulcer disease underwent a laparoscopic intraperitoneal placement of mesh for incisional hernia utilising a fish oil coated polypropylene mesh. The patient presented 3 months after the procedure complaining of dyspepsia and pain at the operative site. There was no discharge. The patient was managed conservatively. She presented 10 months post-operatively with progressively worsening symptoms and a hard palpable mass in the epigastrium. Abdominal laparoscopy revealed dense adhesive disease around the mesh with exudates. Adhesiolysis, mesh explantation and a partial gastrectomy was performed. Histopathological examination revealed a foreign body granuloma formation to the mesh.

Conclusion

In-vivo studies looking at intraperitoneal mesh placement with fish oil coatings including data on surgical outcomes such as fistula and adhesive characteristics are scarce in the literature. Further monitoring and studies are required to investigate the safety and efficacy profile of this mesh type in in-vivo models.

Evolution and advances in laparoscopic ventral and incisional hernia repair

Primary ventral hernias and ventral incisional hernias have been a challenge for surgeons throughout the ages. In the current era, incisional hernias have increased in prevalence due to the very high number of laparotomies performed in the 20^th century. Even though minimally invasive surgery and hernia repair have evolved rapidly, general surgeons have yet to develop the ideal, standardized method that adequately decreases common postoperative complications, such as wound failure, hernia recurrence and pain. The evolution of laparoscopy and ventral hernia repair will be reviewed, from the rectoscopy of the 4^th century to the advent of laparoscopy, from suture repair to the evolution of mesh reinforcement. The nuances of minimally invasive ventral and incisional hernia repair will be summarized, from preoperative considerations to variations in intraoperative practice. New techniques have become increasingly popular, such as primary defect closure, retrorectus mesh placement, and concomitant component separation. The advent of robotics has made some of these repairs more feasible, but only time and well-designed clinical studies will tell if this will be a durable modality for ventral and incisional hernia repair.

Tracking of Drug Release and Material Fate for Naturally Derived Omega-3 Fatty Acid Biomaterials

In vitro and in vivo studies were conducted on omega-3 fatty acid-derived biomaterials to determine their utility as an implantable material for adhesion prevention following soft tissue hernia repair and as a means to allow for the local delivery of antimicrobial or antibiofilm agents. Naturally derived biomaterials offer several advantages over synthetic materials in the field of medical device development. These advantages include enhanced biocompatibility, elimination of risks posed by the presence of toxic catalysts and chemical crosslinking agents, and derivation from renewable resources. Omega-3 fatty acids are readily available from fish and plant sources and can be used to create implantable biomaterials either as a stand-alone device or as a device coating that can be utilized in local drug delivery applications. In-depth characterization of material erosion degradation over time using non-destructive imaging and chemical characterization techniques provided mechanistic insight into material structure: function relationship. This in turn guided rational tailoring of the material based on varying fatty acid composition to control material residence time and hence drug release. These studies demonstrate the utility of omega-3 fatty acid derived biomaterials as an absorbable material for soft tissue hernia repair and drug delivery applications.

Sustained Efficacy and Arterial Drug Retention by a Fast Drug Eluting Cross-Linked Fatty Acid Coronary Stent Coating

The long held assumption that sustained drug elution from stent coatings over weeks to months is imperative for clinical efficacy has limited the choice for stent coating materials. We developed and evaluated an omega-3 fatty acid (O3FA) based stent coating that is 85% absorbed and elutes 97% of its Sirolimus analog (Corolimus) load within 8d of implantation. O3FA coated stents sustained drug levels in porcine coronary arteries similarly to those achieved by slow-eluting durable coated Cypher Select Plus Stents and with significantly lower levels of granuloma formation and luminal stenosis. Computational modeling confirmed that diffusion and binding constants of Corolimus and Sirolimus are identical and explained that the sustained retention of Corolimus was facilitated by binding to high affinity intracellular receptors (FKBP12). First in man outcomes were positive-unlike Cypher stents where late lumen loss drops over 6 month, there was a stable effect without diminution in the presence of O3FA. These results speak to a new paradigm whereby the safety of drug eluting stents can be optimized through the use of resorbable biocompatible coating materials with resorption kinetics that coincide with the dissociation and tissue elimination of receptor-bound drug.

Laparoscopic ventral/incisional hernia repair: updated Consensus Development Conference based guidelines [corrected]

BACKGROUND

The Executive board of the Italian Society for Endoscopic Surgery (SICE) promoted an update of the first evidence-based Italian Consensus Conference Guidelines 2010 because a large amount of literature has been published in the last 4 years about the topics examined and new relevant issues.

METHODS

The scientific committee selected the topics to be addressed: indications to surgical treatment including special conditions (obesity, cirrhosis, diastasis recti abdominis, acute presentation); safety and outcome of intraperitoneal meshes (synthetic and biologic); fixing devices (absorbable/non-absorbable); abdominal border and parastomal hernia; intraoperative and perioperative complications; and recurrent ventral/incisional hernia. All the recommendations are the result of a careful and complete literature review examined with autonomous judgment by the entire panel. The process was supervised by experts in methodology and epidemiology from the most qualified Italian institution. Two external reviewers were designed by the EAES and EHS to guarantee the most objective, transparent, and reliable work. The Oxford hierarchy (OCEBM Levels of Evidence Working Group*. "The Oxford 2011 Levels of Evidence") was used by the panel to grade clinical outcomes according to levels of evidence. The recommendations were based on the grading system suggested by the GRADE working group.

RESULTS AND CONCLUSIONS

The availability of recent level 1 evidence (a meta-analysis of 10 RCTs) allowed to recommend that not only laparoscopic repair is an acceptable alternative to the open repair, but also it is advantageous in terms of shorter hospital stay and wound infection rate. This conclusion appears to be extremely relevant in a clinical setting. Indications about specific conditions could also be issued: laparoscopy is recommended for the treatment of recurrent ventral hernias and obese patients, while it is a potential option for compensated cirrhotic and childbearing-age female patients. Many relevant and controversial topics were thoroughly examined by this consensus conference for the first time. Among them are the issue of safety of the intraperitoneal mesh placement, traditionally considered a major drawback of the laparoscopic technique, the role for the biologic meshes, and various aspects of the laparoscopic approach for particular locations of the defect such as the abdominal border or parastomal hernias.

Titanium versus absorbable tacks comparative study (TACS): a multicenter, non-inferiority prospective evaluation during laparoscopic repair of ventral and incisional hernia: study protocol for randomized controlled trial

BACKGROUND

Laparoscopic repair of ventral and incisional hernias has gained popularity since many studies have reported encouraging results in terms of outcomee and recurrence. Choice of mesh and fixation methods are considered crucial issues in preventing recurrences and complications. Lightweight meshes are considered the first choice due to their biomechanical properties and the ability to integrate into the abdominal wall. Titanium helicoidal tacks still represent the "gold standard" for mesh fixation, even if they have been suggested to be involved in the genesis of post-operative pain and complications. Recently, absorbable tacks have been introduced, under the hypothesis that there will be no need to maintain a permanent fixation device after mesh integration. Nevertheless, there is no evidence that absorbable tacks may guarantee the same results as titanium tacks in terms of strength of fixation and recurrence rates. The primary end point of the present trial is to test the hypothesis that absorbable tacks are non-inferior to titanium tacks in laparoscopic incisional and ventral hernia repair (LIVHR) by lightweight polypropylene mesh, in terms of recurrence rates at 3-year follow-up. Surgical complications, post-operative stay, comfort and pain are secondary end points to be assessed.

METHODS/DESIGN

Two hundred and twenty patients with ventral hernia will be randomized into 2 groups: Group A (110) patients will be submitted to LIVHR by lightweight polypropylene mesh fixed by titanium tacks; Group B (110) patients will be submitted to LIVHR by lightweight polypropylene mesh fixed by absorbable tacks.

DISCUSSION

A few retrospective studies have reported similar results when comparing absorbable versus non-absorbable tacks in terms of intraoperative and early post-operative outcomes. These studies have the pitfalls to be retrospective evaluation of small series of patients, and the reported results still need to be validated by larger series and prospective studies. The aim of the present trial is to investigate and test the non-inferiority of absorbable versus non-absorbable tacks in terms of hernia recurrence rates, in order to assess whether the use of absorbable tacks may achieve the same results as non-absorbable tacks in mid-term and long-term settings.

TRIAL REGISTRATION NUMBER

NCT02076984: 5 June 2014 (ClinicalTrials.gov).

Tissue integration and inflammatory reaction in full-thickness abdominal wall repair using an innovative composite mesh

PURPOSE

When composite meshes are used in abdominal wall repair, seroma formation may persist and delay the desired integration leading to recurrence. This study compares tissue integration and inflammatory response in abdominal wall repair with composites with different absorbable synthetic barriers.

METHODS

Full-thickness defects created in the abdominal wall of rabbits were repaired using polypropylene prosthesis or the following composites: Physiomesh™ (Phy); Ventralight™ (Vent) and "new composite mesh" (Ncm) not yet used clinically in humans. The collected seroma was evaluated for IFN-γ/IL-4 by ELISA. Tissue integration, anti- (IL-13/TGFβ-1/IL-10/IL-4) and pro-inflammatory (TNF-α/IL-6/IFN-γ/VEGF) cytokine mRNA expression and TGFβ/VEGF immunolabeling were evaluated at 14 and 90 days post-implant.

RESULTS

Seroma was observed in 10 of 12 Phy/Vent and 4 of 12 Ncm. Wound fluid IFN-γ showed a time-dependent significant increase in Vent and tendency to decrease in Ncm, while all composites exhibited IL-4 upward trend. Prostheses were fully infiltrated by an organized connective tissue at end time although the area had shown prior seroma. A stable mesothelium was developed, except in adhesion areas. Vent/Phy displayed a significant increase in TNF-α/IFN-γ-mRNA over time. Significant decrease in VEGF mRNA was observed in Phy/Ncm, while a significant increase of TGFβ-1 mRNA was evident in all composites over time. Ncm exhibited the highest TGFβ protein expression area at short term and the greatest percentage of VEGF positive vessels at end time.

CONCLUSION

Ncm could be an appropriate candidate to improve clinical outcome showing the lower development of seroma and optimal tissue integration with minimal pro-inflammatory cytokine response over time and consistent pro-wound healing cytokine expression.

Biaxial analysis of synthetic scaffolds for hernia repair demonstrates variability in mechanical anisotropy, non-linearity and hysteresis

BACKGROUND

Over the past 60 years, the soft tissue repair market has grown to include over 50 types of hernia repair materials. Surgeons typically implant these materials in the orientation that provides maximum overlap of the mesh over the defect, with little regard for mechanical properties of the mesh material. If the characteristics of the meshes were better understood, an appropriate material could be identified for each patient, and meshes could be placed to optimize integration with neighboring tissue and avoid the mechanical mis-match that can lead to impaired graft fixation. The purpose of this study was to fully characterize and compare the mechanical properties of thirteen types of hernia repair materials via planar biaxial tensile testing.

METHODS

Equibiaxial (i.e., equal simultaneous loading in both directions) and strip biaxial (i.e., loading in one direction with the other direction held fixed) tests were utilized as physiologically relevant loading regimes. After applying a 0.1N pre-load on each arm, samples were subjected to equibiaxial cyclic loading using a triangular waveform to 2.5mm displacement on each arm at 0.1Hz for 10 cycles. Samples were then subjected to two strip biaxial tests (using the same cyclic loading protocol), where extension was applied along a single axis with the other axis held fixed.

RESULTS

The thirteen evaluated mesh types exhibited a wide range of mechanical properties. Some were nearly isotropic (C-QUR™, DUALMESH(®), PHYSIOMESH™, and PROCEED(®)), while others were highly anisotropic (Ventralight™ ST, Bard™ Mesh, and Bard™ Soft Mesh). Some displayed nearly linear behavior (Bard™ Mesh), while others were non-linear with a long toe region followed by a sharp rise in tension (INFINIT(®)). These materials are currently utilized in clinical settings as if they are uniform and interchangeable, and clearly this is not the case. The mechanical properties most advantageous for successful hernia repairs are currently only vaguely described in the clinical literature. The characteristics of the human abdominal wall must be extensively characterized to provide a thorough understanding of the tissue being reinforced/replaced by these meshes. A better understanding of these mechanical differences would enable matching of patient characteristics to a specific mesh with the properties best suited to that particular repair.