Ventral hernia repair with poly-4-hydroxybutyrate mesh

Mesh exposure after ventral hernia repair with onlay biosynthetic mesh: a retrospective review of associated risk factors and management strategies

BACKGROUND

Although intraperitoneal and retromuscular mesh placement in ventral hernia repair (VHR) are associated with lower recurrence rates, the onlay plane remains a well-established option for certain clinical scenarios. A knowledge gap remains regarding resorbable biosynthetic onlay mesh and mesh exposure. We aim to determine exposure rate, risk factors, and treatment options.

STUDY DESIGN

A single-center, two-surgeon retrospective review was performed examining patients who underwent VHR with onlay, Poly-4-hydroxybutyrate (P4HB) mesh from 2015 to 2021. Demographics, operative characteristics, outcomes, and mesh exposure management were analyzed.

RESULTS

Of 346 patients, 15 (4.3%) experienced mesh exposure. The mean age was 53 years and BMI of 33.6 kg/m2. Patients were majority ASA class 3 (65%), female (64.2%), and averaged a defect size of 307.9 ± 235.2 cm2. Independent risk factors included diabetes (AOR = 4.3,CI 1.5-12.5;p < 0.005) and COPD (AOR = 5.2,CI 1.3-21.8;p = 0.02). Mesh exposures were identified as outpatient (20%) or intraoperative (80%). All underwent operative debridement, in which nine were managed with skin reclosure, two with partial closure, and four healed by secondary intention. Five patients required excision of unincorporated mesh. Four patients required further debridement from chronic surgical site occurrences; however, all mesh exposure patents healed after a mean of 260.8 ± 313.2 days and retained original mesh. The recurrence rate was 6.7% for mesh exposure patients.

CONCLUSION

When faced with mesh exposure, resorbable biosynthetic mesh placed in onlay fashion was retained in all patients. Patients with a history of diabetes or COPD have increased risk of mesh exposure and should be counseled.

Emerging materials and technologies for advancing bioresorbable surgical meshes

Surgical meshes play a significant role in the treatment of various medical conditions, such as hernias, pelvic floor issues, guided bone regeneration, and wound healing. To date, commercial surgical meshes are typically made of non-absorbable synthetic polymers, notably polypropylene and polytetrafluoroethylene, which are associated with postoperative complications, such as infections. Biological meshes, based on native tissues, have been employed to overcome such complications, though mechanical strength has been a main disadvantage. The right balance in mechanical and biological performances has been achieved by the advent of bioresorbable meshes. Despite improvements, recurrence of clinical complications associated with surgical meshes raises significant concerns regarding the technical adequacy of current materials and designs, pointing to a crucial need for further development. To this end, current research focuses on the design of meshes capable of biomimicking native tissue and facilitating the healing process without post-operative complications. Researchers are actively investigating advanced bioresorbable materials, both synthetic polymers and natural biopolymers, while also exploring the performance of therapeutic agents, surface modification methods and advanced manufacturing technologies such as 4D printing. This review seeks to evaluate emerging biomaterials and technologies for enhancing the performance and clinical applicability of the next-generation surgical meshes. STATEMENT OF SIGNIFICANCE: In the ever-transforming landscape of regenerative medicine, the embracing of engineered bioabsorbable surgical meshes stands as a key milestone in addressing persistent challenges and complications associated with existing treatments. The urgency to move beyond conventional non-absorbable meshes, fraught with post-surgery complications, emphasises the necessity of using advanced biomaterials for engineered tissue regeneration. This review critically examines the growing field of absorbable surgical meshes, considering their potential to transform clinical practice. By strategically combining mechanical strength with bioresorbable characteristics, these innovative meshes hold the promise of mitigating complications and improving patient outcomes across diverse medical applications. As we navigate the complexities of modern medicine, this exploration of engineered absorbable meshes emerges as a promising approach, offering an overall perspective on biomaterials, technologies, and strategies adopted to redefine the future of surgical meshes.

Long-term results with biosynthetic absorbable P4HB mesh in ventral abdominal wall repair: a multicentre analysis

BACKGROUND

The aim of this multicentre study was to analyse the outcomes of biosynthetic absorbable poly-4-hydroxybutyrate (P4HB) prosthesis implantation in patients undergoing ventral hernia repair (VHR) in the context of different degrees of contamination.

METHODS

From May 2016 to December 2021, a multicentre retrospective analysis of patients who underwent elective or urgent hernia repair with P4HB prosthesis was performed in seven hospitals in Spain and Portugal. Patients with a postoperative follow-up of less than 20 months and those within the theoretical period of prosthesis resorption were excluded from the study. Regarding the degree of contamination, patients were assessed according to the modified Ventral Hernia Working Group (VHWG) classification. Epidemiological data, hernia characteristics, surgical and postoperative variables (Clavien-Dindo classification) of these patients were analyzed. Risk factors related to long-term recurrence were studied by a multivariate analysis.

RESULTS

In 236 cases of P4HB prosthesis implantation, repair in cases of Grade 3 was the most frequent (49.1%), followed by Grade 2 in 42.3% of cases and Grade 1 in 8.4%. The most frequent complications were Grade 1, with the majority occurring during the first year. The overall rate of surgical site occurrences (SSO) was 30%. The hernia recurrence rate was 14.4% (n = 34), with a mean postoperative follow-up time of 41 months (22-61). The multivariate analysis showed that the onlay location of the mesh (OR 1.07; CI 1.42-2.70, p = 0.004) was a significant independent risk factor for recurrence.

CONCLUSIONS

The use of a P4HB bioresorbable mesh for the VHR with different degrees of contamination leads to favourable results overall, with an acceptable rate of hernia recurrence. The onlay location of the P4HB prosthesis is the main factor in recurrence in both elective and emergency settings.

The use of poly-4-hydroxybutyrate (P4HB, Phasix™) mesh in ventral hernia repair: a systematic review and meta-analysis

PURPOSE/BACKGROUND

Despite the growing use of bioabsorbable mesh in ventral hernia repairs (VHR), the evidence of its impact on patient outcomes remains limited. This study aims to investigate the efficacy and safety profile of poly-4-hydroxybutyrate (P4HB) mesh for ventral hernia repair through a systematic review and meta-analysis.

METHODS

A literature search of five databases (PubMed, Embase, Ovid, Medline, and Google Scholar) produced a list of publications that analyzed the use of P4HB mesh in ventral hernia repair in both clean and contaminated cases. The primary postoperative outcomes of hernia recurrence, surgical site infections (SSI), and any complications were analyzed through a pooled meta-analysis.

RESULTS

In our systematic review, 21 studies met the inclusion criteria with a total of 1858 patients (933 males and 925 females) and an average age of 56.8 years. The median follow-up ranged from 1.6 to 62.3 months. In our meta-analysis, the use of P4HB mesh in VHR in proportion of events demonstrated a recurrence rate of 9% [6%; 15%], SSI of 10% [6%; 16%] and 35% [9%; 42%] for rate of any complications. Sub-meta-analysis restricted to studies with follow up > 18 months continues to show low rates of recurrence of 9% (95%CI, 4-17%), SSI of 9% (95%CI, 4-16%), and 31% (95%CI, 23-41%) for any complications.

CONCLUSION

Our study demonstrates that the use of P4HB mesh is both safe and effective in ventral hernia repairs. When further analyzed past 18 months, the time where P4HB mesh fully resorbs, the rates of hernia recurrence, SSI, and any complications remain low of upwards of 5 years and comparable to the rates seen in synthetic and biologics in similar patient populations.

Ventral hernia repair using bioresorbable poly-4-hydroxybutyrate mesh in clean and contaminated surgical fields: a systematic review and meta-analysis

PURPOSE

Use of biologic or synthetic mesh in hernia repair shifts is based on evolving evidence. Poly-4-hydroxybutyrate (P4HB) biosynthetic mesh is a potential alternative to biologic and synthetic mesh in ventral hernia repair (VHR). This meta-analysis assesses the efficacy of P4HB mesh in clean and contaminated surgical settings.

METHODS

Two authors searched literature on PubMed, reviewing titles and abstracts of all articles to determine inclusion eligibility. Post-operative data were compared via transformation method to convert the proportion of patients with the outcome of interest into a suitable quantity for random-effects synthesis using STATA software.

RESULTS

Initial search yielded 287 citations. Six studies were included and categorized on whether hernia repairs were conducted in clean (CDC class I) or contaminated cases (CDC class II-IV). The pooled proportion of surgical site infection (SSI), surgical site occurrence (SSO), hernia recurrence, total surgical complications, and reoperation were calculated in 391 clean and 81 contaminated cases. For clean vs. contaminated cases, the following pooled proportions were noted: SSI (2% (CI 0-7%) vs 9% (CI 0-025) (p = 0.03), SSO: 14% (CI 5-25%) vs 35% (CI 22-50%) (p = 0.006), hernia recurrence (8% (CI 1-19%) vs 4% (CI 0-12%) (p = 0.769); surgical complications (17% (CI 6-32%) vs 50% (CI 27-72%) (p = 0.009). Reoperation data were available in 298 clean cases across four studies: 5% (CI 0-15%).

CONCLUSIONS

P4HB biosynthetic mesh may be more effective than previously thought, particularly in clean wounds. P4HB may also be superior to biologic mesh when compared to clinical trial data. Further research is necessary for more direct comparison.

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.

Early wound morbidity and clinical outcomes associated with P4HB mesh compared to permanent synthetic mesh in umbilical and small to medium, routine ventral hernia repairs

Background

Permanent synthetic meshes such as polypropylene (PP) have been utilized for hernia repair for decades, but concerns remain regarding potential long-term, mesh-related complications. A resorbable polymer such as poly-4-hydroxybutyrate (P4HB) represents an alternative with high initial strength, that gradually resorbs, leaving an abdominal wall that is at least as strong as it would be in its native state. We aimed to compare early wound morbidity and clinical outcomes associated with P4HB to traditional, permanent PP in umbilical and small to medium, routine ventral hernias using data from the Abdominal Core Health Quality Collaborative (ACHQC).

Methods

Inclusion criteria for the umbilical cohort included: all Centers for Disease Control and Prevention (CDC) wound classes, all Ventral Hernia Working Group (VHWG) hernia grades, and hernia defects <3 cm. The small to medium, routine ventral hernia cohort was limited to CDC class I wounds, VHWG hernia grades I and II, and hernia defects <5 cm. The study group was comprised of P4HB meshes; the comparator group was an aggregate of PP meshes. Clinical outcomes were assessed at 30 days.

Results

There was no significant difference in early wound morbidity, readmission, or reoperation between the P4HB and PP cohorts. A small number of patients experienced SSO, with ≤4% requiring procedural intervention. None of the patients (0% in all cases) experienced skin/soft tissue necrosis, infected seroma, infected hematoma, exposed/contaminated/infected mesh, enterocutaneous fistula, graft failure, or pain requiring intervention at 30-days. However, P4HB was associated with significantly greater operative time, length of stay, and use of myofascial release compared to PP (p < 0.05 in all cases).

Conclusions

Short-term clinical outcomes associated with resorbable P4HB mesh are comparable to permanent synthetic PP mesh in umbilical and small to medium, routine ventral hernia repairs, despite significant differences in operative time and length of stay. Longer-term follow-up is needed to expand on the clinical relevance of these short-term findings.

Novel Material Optimization Strategies for Developing Upgraded Abdominal Meshes

Over 20 million hernias are operated on globally per year, with most interventions requiring mesh reinforcement. A wide range of such medical devices are currently available on the market, most fabricated from synthetic polymers. Yet, searching for an ideal mesh is an ongoing process, with continuous efforts directed toward developing upgraded implants by modifying existing products or creating innovative systems from scratch. In this regard, this review presents the most frequently employed polymers for mesh fabrication, outlining the market available products and their relevant characteristics, further focusing on the state-of-the-art mesh approaches. Specifically, we mainly discuss recent studies concerning coating application, nanomaterials addition, stem cell seeding, and 3D printing of custom mesh designs.

Fully resorbable poly-4-hydroxybutyrate (P4HB) mesh for soft tissue repair and reconstruction: A scoping review

Background

Poly-4-hydroxybutyrate (P4HB) is a fully resorbable, biologically-produced polymer with a strength and flexibility comparable to permanent synthetic polymers. The objective was to identify/summarize all peer-reviewed publications involving P4HB mesh.

Methods

A scoping review was conducted within PubMed and included articles published through October 2022.

Results

A total of n = 79 studies were identified (n = 12 in vitro/bench; n = 14 preclinical; n = 6 commentaries; n = 50 clinical). Of the clinical studies, n = 40 reported results applicable to hernia and n = 10 to plastic/reconstructive surgery and involved patients of all Centers for Disease Control (CDC) wound classes and Ventral Hernia Working Group (VHWG) grades.

Conclusion

P4HB mesh provides long-term hernia repair strength and exhibits promising clinical outcomes beyond its resorption period. Future studies should include randomized controlled trials comparing P4HB to other biomaterials, as well as optimal patient selection, operative technique, long-term outcomes, minimization of potential mesh-related complications, and potential contraindications/complications for P4HB in hernia/abdominal wall reconstruction.

Long-Term, Prospective, Multicenter Study of Poly-4-Hydroxybutyrate Mesh (Phasix Mesh) for Hernia Repair in Cohort at Risk for Complication: 60-Month Follow-Up

BACKGROUND

Long-term resorbable mesh represents a promising technology for ventral and incisional hernia repair (VIHR). This study evaluates poly-4-hydroxybutyrate mesh (P4HB; Phasix Mesh) among comorbid patients with CDC class I wounds.

STUDY DESIGN

This prospective, multi-institutional study evaluated P4HB VIHR in comorbid patients with CDC class I wounds. Primary outcomes included hernia recurrence and surgical site infection. Secondary outcomes included pain, device-related adverse events, quality of life, reoperation, procedure time, and length of stay. Evaluations were scheduled at 1, 3, 6, 12, 18, 24, 30, 36, and 60 months. A time-to-event analysis (Kaplan-Meier) was performed for primary outcomes; secondary outcomes were reported as descriptive statistics.

RESULTS

A total of 121 patients (46 male, 75 female) 54.7 ± 12.0 years old with a BMI of 32.2 ± 4.5 kg/m 2 underwent VIHR with P4HB Mesh (mean ± SD). Fifty-four patients (44.6%) completed the 60-month follow-up. Primary outcomes (Kaplan-Meier estimates at 60 months) included recurrence (22.0 ± 4.5%; 95% CI 11.7% to 29.4%) and surgical site infection (10.1 ± 2.8%; 95% CI 3.3 to 14.0). Secondary outcomes included seroma requiring intervention (n = 9), procedure time (167.9 ± 82.5 minutes), length of stay (5.3 ± 5.3 days), reoperation (18 of 121, 14.9%), visual analogue scale-pain (change from baseline -3.16 ± 3.35 cm at 60 months; n = 52), and Carolinas Comfort Total Score (change from baseline -24.3 ± 21.4 at 60 months; n = 52).

CONCLUSIONS

Five-year outcomes after VIHR with P4HB mesh were associated with infrequent complications and durable hernia repair outcomes. This study provides a framework for anticipated long-term hernia repair outcomes when using P4HB mesh.

Establishing Peer Consensus About the Use of Long-Term Biosynthetic Absorbable Mesh for Hernia (Grades 2-3) as the Standard of Care

BACKGROUND

Standard synthetic and biologic meshes, often used in hernia repair, have commonly been used and each have their strengths but associated drawbacks. Long-term biosynthetic absorbable (LTBA) mesh has been developed to combine the strengths of synthetic and biologic meshes without the associated weaknesses. As a newer type of mesh, the supporting evidence base is still growing, and their optimum use has yet to be defined. This consensus was initiated to provide insight into those situations where a LTBA might be considered the Standard of Care in ventral hernia repair grades 2-3 (original classification, 2010) of the Ventral Hernia Working Group.

METHODS

A steering group of expert surgeons identified 35 statements, based around the evidence supporting LTBA, surgical technique, patients type most suitable for LTBA, risk-benefit of LTBA, patient and surgeon considerations, LTBA value. Surgeons involved in hernia repair received an online survey to assess consensus with these statements. Consensus was defined as high if ≥ 70% and very high if ≥ 90% of respondents agreed. Statements that had not achieved consensus agreement were revised and these were then issued for a subsequent round. Finally, 34 statements were included.

RESULTS

Two hundred fifty-five surgeons were involved. Fourteen statements (41%) achieved very high consensus, 24 achieved consensuses (≥ 70-< 90%), whilst one (3%) just failed to achieve consensus with an agreement score of 69%.

CONCLUSIONS

Expert consensus opinion about the use of LTBA for hernia (Grades 2-3) as the Standard of Care was achieved. Based on the consensus scores, the steering group derived eleven keys.

Ventral hernia repair in high-risk patients and contaminated fields using a single mesh: proportional meta-analysis

PURPOSE

The use of mesh is a common practice in ventral hernia repair (VHR). Lack of consensus on which prosthetic material works better in different settings remains. This meta-analysis aims to summarize the available evidence on hernia recurrence and complications after repair with synthetic, biologic, or biosynthetic/bioabsorbable meshes in hernias grade 2-3 of the Ventral Hernia Working Group modified classification.

METHODS

A literature search was conducted in January 2021 using Web of Science (WoS), Scopus, and MEDLINE (via PubMed) databases. Randomized Controlled Trials (RCTs) and observational studies with adult patients undergoing VHR with either synthetic, biologic, or biosynthetic/bioabsorbable mesh were included. Outcomes were hernia recurrence, Surgical Site Occurrence (SSO), Surgical Site Infection (SSI), 30 days re-intervention, and infected mesh removal. Random-effects meta-analyses of pooled proportions were performed. Quality of the studies was assessed, and heterogeneity was explored through sensitivity analyses.

RESULTS

25 articles were eligible for inclusion. Mean age ranged from 47 to 64 years and participants' follow-up ranged from 1 to 36 months. Biosynthetic/bioabsorbable mesh reported a 9% (95% CI 2-19%) rate of hernia recurrence, lower than synthetic and biologic meshes. Biosynthetic/bioabsorbable mesh repair also showed a lower incidence of SSI, with a 14% (95% CI 6-24%) rate, and there was no evidence of infected mesh removal. Rates of seroma were similar for the different materials.

CONCLUSIONS

This meta-analysis did not show meaningful differences among materials. However, the best proportions towards lower recurrence and complication rates after grade 2-3 VHR were after using biosynthetic/slowly absorbable mesh reinforcement. These results should be taken with caution, as head-to-head comparative studies between biosynthetic and synthetic/biologic meshes are lacking. Although, biosynthetic/bioabsorbable materials could be considered an alternative to synthetic and biologic mesh reinforcement in these settings.

Slowly absorbable mesh versus standard care in the management of contaminated midline incisional hernia (COMpACT-BIO): a multicentre randomised controlled phase III trial including a health economic evaluation

INTRODUCTION

Incisional hernia (IH) is the most frequent mid-term and long-term complication after midline laparotomy. The current standard treatment includes repair using a mesh. In a contaminated field, the use of a non-absorbable mesh increases the risk of surgical site infection and the costs. Slowly absorbable meshes are safe in contaminated fields, but no data have been reported regarding their long-term recurrence rate. COMpACT-BIO is a multicentre prospective randomised controlled phase III trial designed to compare the 3-year recurrence rate in patients undergoing contaminated IH repair with either a slowly absorbable mesh or standard care.

METHODS

In patients undergoing midline IH repair in a contaminated surgical field (grade III of the modified Ventral Hernia Working Group classification), the COMpACT-BIO study compares the use of a slowly absorbable mesh with that of conventional care according to standardised surgical procedures (primary closure, non-absorbable synthetic mesh or biologic mesh, at the discretion of the surgeon). Randomisation is done during surgery before closure the fascia with an allocation ratio of 1:1. The choice of the slowly absorbable mesh is left to the criteria of each centre. The primary endpoint is the proportion of patients with scan-confirmed IH recurrence within 3 years after repair.

ETHICS/DISSEMINATION

This trial is conducted in compliance with international standards for research practice and reporting. Written informed consent will be obtained from patients prior to inclusion. All data were identified and anonymised prior to analysis. The protocol has been approved by an Institutional Review Board (2020-A0823-36/SI:20.07.03.66831), and will be conducted in compliance with the CONSORT (Consolidated Standards of Reporting Trials) statement. Results will be submitted for publication in peer-reviewed medical journals and presented to patients and healthcare professionals.

PROTOCOL VERSION

Version 2-13 October 2020.

TRIAL REGISTRATION NUMBER

NCT04597840.

Comparative Effectiveness Analysis of Resorbable Synthetic Onlay and Biologic Intraperitoneal Mesh for Abdominal Wall Reconstruction: A 2-Year Match-Paired Analysis

BACKGROUND

Abdominal wall reconstruction persists as a challenging surgical issue with a multitude of management strategies available. The aim of this study was to examine the efficacy of resorbable synthetic mesh onlay plane against biologic mesh in the intraperitoneal plane.

METHODS

A single-center, two-surgeon, 5-year retrospective review (2014 to 2019) was performed examining subjects who underwent abdominal wall reconstruction in the onlay plane with resorbable synthetic mesh or in the intraperitoneal plane with biologic mesh. A matched paired analysis was conducted. Data examining demographic characteristics, intraoperative variables, postoperative outcomes, and costs were analyzed.

RESULTS

Eighty-eight subjects (44 per group) were identified (median follow-up, 24.5 months). The mean age was 57.7 years, with a mean body mass index of 30.4 kg/m2. The average defect size was 292 ± 237 cm2, with most wounds being clean-contaminated (48.9 percent) and 55 percent having failed prior repair. Resorbable synthetic mesh onlay subjects were significantly less likely (4.5 percent) to experience recurrence compared to biologic intraperitoneal mesh subjects (22.7 percent; p < 0.026). In addition, mesh onlay suffered fewer postoperative surgical-site occurrences (18.2 percent versus 40.9 percent; p < 0.019) and required fewer procedural interventions (11.4 percent versus 36.4 percent; p < 0.011), and was also associated with significantly lower total costs ($16,658 ± $14,930) compared to biologic intraperitoneal mesh ($27,645 ± $16,864; p < 0.001).

CONCLUSIONS

Abdominal wall reconstruction remains an evolving field, with various techniques available for treatment. When faced with hernia repair, resorbable synthetic mesh in the onlay plane may be preferable to biologic mesh placed in the intraperitoneal plane because of lower long-term recurrence rates, surgical-site complications, and costs.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

VERSATILITY OF POLY-4-HYDROXYBUTYRATE (PHASIX™) MESH IN ABDOMINAL WALL SURGERY

BACKGROUND

Poly-4-hydroxybutyrate (P4HB) is a naturally occurring polymer derived from transgenic E. coli bacteria with the longest degradation rate when compared to other available products. This polymer has been manufactured as a biosynthetic mesh to be used as reinforcement when repairing a variety of abdominal wall defects.

OBJECTIVE

We aim to describe our center initial experience with this mesh and discuss the possible indications that may benefit from the use of P4HB mesh.

METHODS

This is a descriptive retrospective study of patients who underwent abdominal wall repair with a P4HB mesh from October 2018 to December 2020 in a single, large volume, academic center.

RESULTS

A total of 51 patients (mean age 54.4 years, range 12-89) underwent abdominal wall reconstruction with a P4HB mesh between October 2018 and December 2020. The mean BMI was 30.5 (range 17.2-50.6). Twenty-three (45%) patients had a prior hernia repair at the site. We grouped patients into six different indications for the use of P4HB mesh in our cohort: clean-contaminated, contaminated or infected field (57%), patient refusal for permanent meshes (14%), those with high risk for post-operative infection (12%), visceral protection of second mesh (10%), recurrence with related chronic pain from mesh (6%), and children (2%). Median follow-up was 105 days (range 8-648). Two patients had hernia recurrence (4%) and 8 (16%) patients developed seroma.

CONCLUSION

P4HB mesh is a safe and a viable alternative for complex hernias and high-risk patients with a low complication rate in the short-term.

Favourable outcomes after Retro-Rectus (Rives-Stoppa) Mesh Repair as Treatment for Non-Complex Ventral Abdominal Wall Hernia, a Systematic Review and Meta-Analysis

OBJECTIVE

To assess prevalence of hernia recurrence, surgical site infection (SSI), seroma, serious complications, and mortality after retro-rectus repair.

SUMMARY BACKGROUND DATA

Ventral abdominal wall hernia is a common problem, tied to increasing frailty and obesity of patients undergoing surgery. For non-complex ventral hernia, retro-rectus (Rives-Stoppa) repair is considered the gold standard treatment. Level-1 evidence confirming this presumed superiority is lacking.

METHODS

Five databases were searched for studies reporting on retro-rectus repair. Single-armed and comparative randomized and non-randomized studies were included. Outcomes were pooled with mixed-effects, inverse variance or random-effects models.

RESULTS

Ninety-three studies representing 12440 patients undergoing retro-rectus repair were included. Pooled hernia recurrence was estimated at 3.2% (95%CI: 2.2-4.2%, n = 11049) after minimally 12 months and 4.1%, (95%CI: 2.9-5.5%, n = 3830) after minimally 24 months. Incidences of SSI and seroma were estimated at respectively 5.2% (95%CI: 4.2-6.4%, n = 4891) and 5.5% (95%CI: 4.4-6.8%, n = 3650). Retro-rectus repair was associated with lower recurrence rates compared to onlay repair (OR: 0.27, 95%CI: 0.15-0.51, p < 0.001) and equal recurrence rates compared to intraperitoneal onlay (IPOM) repair (OR: 0.92, 95%CI: 0.75-1.12, p = 0.400). Retro-rectus repair was associated with more SSI than IPOM repair (OR: 1.8, 95%CI: 1.03-3.14, p = 0.038). Minimally invasive retro-rectus repair displayed low rates of recurrence (1.3%, 95%CI: 0.7-2.3%, n = 849) and SSI (1.5%, 95%CI: 0.8-2.8%, n = 982), albeit based on non-randomized studies.

CONCLUSIONS

Retro-rectus (Rives-Stoppa) repair results in excellent outcomes, superior or similar to other techniques for all outcomes except surgical site infection. The latter rarely occurred, yet less frequently after IPOM repair, which is usually performed by laparoscopy.

Laparoscopic Ventral Hernia Repair with Poly-4-Hydroxybutyrate Absorbable Barrier Composite Mesh

Background

Repair of ventral and incisional hernias (VIHR) is a common procedure, newly introduced resorbable mesh biomaterials provide an attractive option to reduce the use of permanent synthetic mesh in hernia surgery and reduce its complications. However, data on the use of slowly resorbable mesh materials remains scarce, this study aims to evaluate the use of poly-4-hydroxybutyrate/absorbable barrier composite mesh (P4HB/ABCM) in laparoscopic repair of VIHR.

Methods

This is a retrospective study of a sequential cohort of patients undergoing laparoscopic VIHR utilizing a P4HB/ABCM mesh. Perioperative characteristics and clinical outcomes were collected.

Results

In total, 26 patients including 10 females and 7 males underwent laparoscopic VIHR using P4HB/ABCM. All surgeries were performed in a single institution by the same surgeon. The average patient age was 52.6, and the mean BMI was 35.5. All patients had a clean wound classification. The average defect size was 136.4 cm². All patients were seen in clinic with a median follow-up of 28 months. We observed 4 wound seromas, and no wound infections or recurrences during the follow-up period.

Conclusion

Results of laparoscopic VIHR with P4HB/ABCM are favorable and encourages further studies on the role of absorbable biosynthetic mesh materials in hernia surgery.

Outcomes of mid-term and long-term degradable biosynthetic meshes in single-stage open complex abdominal wall reconstruction

OBJECTIVE

To assess clinical outcomes in patients that underwent open single-stage complex abdominal wall reconstruction (CAWR) with biosynthetic mesh.

METHODS

Retrospective observational study of two prospectively registered series of consecutive patients undergoing CAWR with either long-term degradable (LTD) Phasix^™ or mid-term degradable (MTD) BIO-A^® biosynthetic mesh in a single institution between June 2016 and December 2019.

RESULTS

From 169 patients with CAWR, 70 consecutive patients were identified who underwent CAWR with either LTD or MTD biosynthetic mesh. More than 85% of patients had an incisional hernia that could be classified as moderately complex to major complex due to a previous wound infection (67%), one or more complicating comorbidities (87.1%), one or more complicating hernia characteristics (75.7%) or contaminated or dirty defects (37.1%). Concomitant component separation was performed in 43 of 70 patients (61.4%). Overall surgical site infection (SSI) rate in these CAWR patients was 45.7%. Seventeen of 70 patients (24.3%) had computed tomography (CT) - and culture-confirmed SSI in direct contact of mesh, suspicious of mesh infection. Mesh removal for persistent local infection occurred in 10% (7 of 70) after a median of 229 days since surgery. Salvage rate of mesh after direct contact with infection was 58.8%. All removed meshes were in the LTD group. Seven patients (10%) had a recurrence; four patients in the LTD group (10%) had a recurrence at a median follow-up of 35 months and three patients in the MTD group (10%) at a median follow-up of 11 months. Three of the seven recurrences occurred in patients with SSI in persistent and direct contact with mesh.

CONCLUSIONS

Comorbid patients undergoing open complex abdominal wall reconstruction are at high risk of postoperative wound complications regardless of which type of biosynthetic mesh is used. When in persistent and direct contact with infection, long-term biodegradable biosynthetic meshes may need to be removed, whereas mid-term biodegradable biosynthetic meshes can be salvaged.

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.

An evaluation of clinical and quality of life outcomes after ventral hernia repair with poly-4-hydroxybutyrate mesh

PURPOSE

Despite continued efforts, recurrence after ventral hernia repair (VHR) remains a common problem. Biosynthetic Phasix^™ (Poly-4-Hydroxybutyrate, P4HB) mesh combines the durability of synthetic mesh with the bio-resistance of biologics. P4HB has shown promising early outcomes, but long-term data are lacking. We examine patients following VHR with P4HB with at least 3 years of follow-up to assess clinical and patient reported outcomes (PROs).

METHODS

Adult patients (≥ 18 years old) undergoing VHR with P4HB mesh between 10/2015 and 01/2018 by a single surgeon were retrospectively identified. Patients with < 36 months of follow-up were excluded unless they had a documented recurrence. Clinical outcomes and quality of life using the Hernia-Related Quality of Life Survey (HerQLes) were assessed.

RESULTS

Seventy-one patients were included with a median age and body mass index of 61.2 and 31 kg/m², respectively. Mesh was placed in the retromuscular (79%) and onlay (21%) planes with 1/3 of patients having hernias repaired in contaminated fields. There were no mesh infections, enterocutaneous fistulas, or mesh explantations. Nine patients (12.7%) developed recurrence at a median follow-up of 43.1 months [38.2-49.1]. Mesh plane, fixation technique, and Ventral Hernia Working Group were not associated with recurrence. Significant improvement in disease-specific PROs was observed and maintained at 3-year follow-up.

CONCLUSION

Longitudinal clinical and quality of life outcomes after clean and contaminated VHR with P4HB are limited. Here, we conclude that P4HB is an effective and versatile mesh option for use in abdominal wall reinforcement.

Long-Term Outcomes in Complex Abdominal Wall Reconstruction Repaired With Absorbable Biologic Polymer Scaffold (Poly-4-Hydroxybutyrate)

Introduction

After promising early outcomes in the use of absorbable biologic mesh for complex abdominal wall reconstruction, significant criticism has been raised over the longevity of these repairs after its 2-year resorption profile.

Methods

This is the long-term (5-year) follow-up analysis of our initial experience with the absorbable polymer scaffold poly-4-hydroxybutyrate (P4HB) mesh compared with a consecutive contiguous group treated with porcine cadaveric mesh for complex abdominal wall reconstructions. Our clinical analysis was performed using Stata 14.2 and Excel 16.16.23.

Results

After a 5-year follow-up period, the P4HB group (n = 31) experienced lower rates of reherniation (12.9% vs 38.1%; P = 0.017) compared with the porcine cadaveric mesh group (n = 42). The median interval in months to recurrent herniation was similar between groups (24.3 vs 20.8; P = 0.700). Multivariate logistic regression analysis on long-term outcomes identified smoking (P = 0.004), African American race (P = 0.004), and the use of cadaveric grafts (P = 0.003) as risks for complication while smoking (P = 0.034) and the use of cadaveric grafts (P = 0.014) were identified as risks for recurrence. The long-term cost analysis showed that P4HB had a $10,595 per case costs savings over porcine cadaveric mesh.

Conclusions

Our study identified the superior outcomes in clinical performance and a value-based benefit of absorbable biologic P4HB scaffold persisted after the 2-year resorption timeframe. Data analysis also confirmed the use of porcine cadaveric grafts independently contributed to the incidence of complications and recurrences.

Successful conservative treatment of a poly-4-hydroxybutyrate mesh infection: A case report

Introduction and importance

An infection of an abdominal wall prosthesis can be a real disaster for the patient. A conservative treatment might be an option if biological or slowly resorbable synthetic meshes were used. However, adequate research of their use in contaminated and dirty wounds lacks.

Case presentation

Herein we report the case of a 69-year-old patient with a heavily infected poly-4-hydroxybutyrate mesh that was successfully treated conservatively.

Clinical discussion

Despite promising results of poly-4-hydroxybutyrate meshes, their use remains controversial and studies in contaminated wounds are scarce.

Conclusion

Our case report shows the potential benefits of a poly-4-hydroxybutyrate mesh in a very high-risk patient with active infection.

Bioabsorbable mesh use in midline abdominal wall prophylaxis and repair achieving fascial closure: a cross-sectional review of stage of innovation

BACKGROUND

Achieving stable closure of complex or contaminated abdominal wall incisions remains challenging. This study aimed to characterise the stage of innovation for bioabsorbable mesh devices used during both midline closure prophylaxis and complex abdominal wall reconstruction and to evaluate the quality of current evidence.

METHODS

A systematic review of published and ongoing studies was performed until 31st December 2019. Inclusion criteria were studies where bioabsorbable mesh was used to support fascial closure either prophylactically after midline laparotomy or for repair of incisional hernia with midline incision. Exclusion criteria were: (1) study design was a systematic review, meta-analysis, letter, review, comment, or conference abstract; (2) included less than p patients; (3) only evaluated biological, synthetic or composite meshes. The primary outcome measure was the IDEAL framework stage of innovation. The key secondary outcome measure was the risk of bias in non-randomised studies of interventions (ROBINS-I) criteria for study quality.

RESULTS

Twelve studies including 1287 patients were included. Three studies considered mesh prophylaxis and nine studies considered hernia repair. There were only two published studies of IDEAL 2B. The remainder was IDEAL 2A studies. The quality of the evidence was categorised as having a risk of bias of a moderate, serious or critical level in nine of the twelve included studies using the ROBINS-I tool.

CONCLUSION

The evidence base for bioabsorbable mesh is limited. Better reporting and quality control of surgical techniques are needed. Although new trial results over the next decade will improve the evidence base, more trials in emergency and contaminated settings are required to establish the limits of indication.

What results can be expected one year after complex incisional hernia repair with biosynthetic mesh?

BACKGROUND

Incisional hernia is a frequent complication after midline laparotomy. The current standard repair includes the use of a synthetic mesh to prevent recurrence. However, the use of a synthetic mesh in a contaminated field carries a higher risk of mesh infection. In this setting biologic and biosynthetic meshes can be used as they resist to infection, but these are absorbable meshes. This raises the question of the risk of recurrence as the mesh disappears. Phasix® is a biosynthetic mesh getting absorbed in 12-18 months. The aim of this study was to assess the 1-year recurrence rate after abdominal-wall repair with a Phasix® mesh.

METHODS

All patients undergoing ventral hernia repair between 2016 and 2018 at the University Hospital of Dijon using a Phasix® mesh were prospectively included in a database. They were all followed-up with a physical exam and a routine CT scan at one year. All postoperative complications were recorded.

RESULTS

Twenty-nine patients were included in the study (55.2% women), with a mean BMI of 30,25 kg/m². Nineteen meshes were sublay and 10 intraperitoneal. Complications at 1 month were mainly mild: Clavien-Dindo I and II (61.1%). No mesh was explanted. There was no chronic infection. The mean length of stay was 11.5 days. The 1-year recurrence rate was 10.3%.

CONCLUSION

Patients having undergone complex ventral hernia repair with a Phasix® mesh have a 1-year recurrence rate of 10.3%. No severe surgical site occurrence was detected. A longer follow-up in a larger number of patients could confirm the place of this mesh in abdominal-wall repair.

A Novel Use of Fully Absorbable PhasixTM Mesh for Laparoscopic Inguinal Hernia Repair

Background and Objectives

An inguinal hernia is usually repaired with synthetic nonabsorbable mesh, resulting in collagen formation, chronic inflammation, and fibrosis, with significantly reduced hernia recurrence. However, chronic pain may affect the quality of life. Poly-4-hydroxybutyrate (P4HB) mesh was introduced to minimize complications, and starts to degrade in 12-18 months. This study assesses the consequences and results of patients undergoing transabdominal preperitoneal (TAPP) inguinal hernia repair using P4HB mesh (Phasix^TM, C.R. Bard Inc., Murray Hill, NJ, USA).

Methods

We performed a pilot study of laparoscopic TAPP repair for inguinal hernias using P4HB mesh in 15 patients (14 male and one female) with an average age of 55.8 y, and an average body mass index of 27.4 kg/m². We assessed the recurrence rate and patients' chronic pain for 30 months, with institutional review board approval (E-19-3735). The study was conducted from January 2016 to July 2017 in Medical City, King Saud University. We measured postoperative pain, reactions, mesh sensation, discomfort, and recurrence.

Results

In 15 patients, we encountered no recurrence or mesh sensation, except in one patient, who experienced mild chronic inguinal pain for one year, without activity restrictions.

Conclusion

Laparoscopic TAPP inguinal hernia repair using P4HB mesh is safe for combined, direct (medial), and indirect (lateral) inguinal hernia, with no recurrence. P4HB absorbable mesh caused less chronic pain and discomfort. Longer follow-up, more patients and 15 patients repaired using synthetic mesh are necessary to assess the utility of P4HB for inguinal hernia repair globally.

Prospective, multicenter study of P4HB (Phasix™) mesh for hernia repair in cohort at risk for complications: 3-Year follow-up

BACKGROUND

This study represents a prospective, multicenter, open-label study to assess the safety, performance, and outcomes of poly-4-hydroxybutyrate (P4HB, Phasix™) mesh for primary ventral, primary incisional, or multiply-recurrent hernia in subjects at risk for complications. This study reports 3-year clinical outcomes.

MATERIALS AND METHODS

P4HB mesh was implanted in 121 patients via retrorectus or onlay technique. Physical exam and/or quality of life surveys were completed at 1, 3, 6,12, 18, 24, and 36 months, with 5-year (60-month) follow-up ongoing.

RESULTS

A total of n = 121 patients were implanted with P4HB mesh (n = 75 (62%) female) with a mean age of 54.7 ± 12.0 years and mean BMI of 32.2 ± 4.5 kg/m2 (±standard deviation). Comorbidities included: obesity (78.5%), active smokers (23.1%), COPD (28.1%), diabetes mellitus (33.1%), immunosuppression (8.3%), coronary artery disease (21.5%), chronic corticosteroid use (5.0%), hypo-albuminemia (2.5%), advanced age (5.0%), and renal insufficiency (0.8%). Hernias were repaired via retrorectus (n = 45, 37.2% with myofascial release (MR) or n = 43, 35.5% without MR), onlay (n = 8, 6.6% with MR or n = 24, 19.8% without MR), or not reported (n = 1, 0.8%). 82 patients (67.8%) completed 36-month follow-up. 17 patients (17.9% ± 0.4%) experienced hernia recurrence at 3 years, with n = 9 in the retrorectus group and n = 8 in the onlay group. SSI (n = 11) occurred in 9.3% ± 0.03% of patients.

CONCLUSIONS

Long-term outcomes following ventral hernia repair with P4HB mesh demonstrate low recurrence rates at 3-year (36-month) postoperative time frame with no patients developing late mesh complications or requiring mesh removal. 5-year (60-month) follow-up is ongoing.

Outcomes of Poly-4-hydroxybutyrate Mesh in Ventral Hernia Repair: A Systematic Review and Pooled Analysis

Within the past decade, poly-4-hydroxybutyrate (P4HB) biosynthetic mesh has been introduced as a potential alternative to traditional biologic and synthetic mesh in ventral hernia repair (VHR). The aim of this study was to systematically assess clinical outcomes with the P4HB in VHR.

Methods

A literature search identified all articles published in 2000 involving the use of P4HB in VHR. Descriptive statistics were used to synthesize collective data points, including postoperative outcomes. A pooled analysis of postoperative outcomes was performed using chi-square test and Fisher exact test.

Results

Across 7 studies, the P4HB was used in 453 patients. The mean rate of surgical site infection (SSI) was 6.8% (31/453), reoperation 10.7% (30/281), and recurrence 9.1% (41/453). At an average follow-up of 26.8 months, the incidence of recurrence was 10.4% (28/270). Onlay was significantly associated with increased recurrence (14.2% versus 4.4%, P = 0.001). Among sublay placements, there was no difference in recurrence in clean (Center for Disease Control [CDC] 1) or contaminated (CDC >1) wounds (2.7% versus 6.1%, P = 0.585), but contaminated wounds were associated with increased SSI (2.7% versus 15.2%, P = 0.028). Ventral Hernia Working Group grade 2 and 3 did not have different incidences of recurrence (8.0% versus 5.1%, P = 0.526) nor SSI (5.1% versus 14.6%, P = 0.265).

Conclusions

Overall, clinical outcomes of the P4HB mesh in VHR are acceptable. The P4HB mesh serves as a reliable alternative to traditional synthetic and biologic mesh across a range of defect characteristics and patient health conditions. Further research is needed to better understand the conditions in which it may provide a clinical benefit over traditional mesh types.

Role of 4-hydroxybutyrate in increased resistance to surgical site infections associated with surgical meshes

An increased resistance to surgical site infections has been associated with surgical meshes composed of naturally occurring materials, including poly-4-hydroxybutrate (4HB). 4HB is a naturally occurring short-chain fatty acid that has been shown to promote endogenous expression of the Cramp gene coding for the antimicrobial peptide (AMP) cathelicidin LL-37 in murine bone marrow-derived macrophages. The molecular pathways involved in the 4HB-induced cathelicidin LL-37 expression have not yet been identified. The present study showed that transcriptional activation of the Cramp gene by 4HB is independent of inhibition of histone deacetylase (HDAC) activity, and that upregulation of Cramp is modulated by the G-protein coupled receptor GPR109A. Furthermore, an intracellular signaling cascade that promotes the activation of the MAP kinases, p38 and JNK, and a subsequent NF-κB phosphorylation downstream from p38 is essential for the AMP transcriptional response in 4HB-stimulated macrophages. The findings provide a solid scientific basis and rationale for the decreased incidence of surgical site infections with the use of this type of surgical meshes. Further clinical significance is found in the fact that the 4HB activated molecular pathway includes common targets of frequently used nonsteroidal anti-inflammatory drugs (NSAIDs) and other FDA approved drugs recognizing G-protein coupled receptors.

Biosynthetic Resorbable Prosthesis is Useful in Single-Stage Management of Chronic Mesh Infection After Abdominal Wall Hernia Repair

BACKGROUND

The goal of this article was to report the results about the efficacy of treatment of chronic mesh infection (CMI) after abdominal wall hernia repair (AWHR) in one-stage management, with complete mesh explantation of infected prosthesis and simultaneous reinforcement with a biosynthetic poly-4-hydroxybutyrate absorbable (P4HB) mesh.

METHODS

This is a retrospective analysis of all patients that needed mesh removal for CMI between September 2016 and January 2019 at a tertiary center. Epidemiological data, hernia characteristics, surgical, and postoperative variables (Clavien-Dindo classification) of these patients were analyzed.

RESULTS

Of the 32 patients who required mesh explantation, 30 received one-stage management of CMI. In 60% of the patients, abdominal wall reconstruction was necessary after the infected mesh removal: 8 cases (26.6%) were treated with Rives-Stoppa repair, 4 (13.3%) with a fascial plication, 1 (3.3%) with anterior component separation, and 1 (3.3%) with transversus abdominis release to repair hernia defects. Three Lichtenstein (10%) and 1 Nyhus repairs (3.3%) were performed in patients with groin hernias. The most frequent postoperative complications were surgical site occurrences: seroma in 5 (20%) patients, hematoma in 2 (6.6%) patients, and wound infection in 1 (3.3%) patient. During the mean follow-up of 34.5 months (range 23-46 months), the overall recurrence rate was 3.3%. Persistent, recurrent, or new CMIs were not observed.

CONCLUSIONS

In our experience, single-stage management of CMI with complete removal of infected prosthesis and replacement with a P4HB mesh is feasible with acceptable results in terms of mesh reinfection and hernia recurrence.

Long term comparative evaluation of two types of absorbable meshes in partial abdominal wall defects: an experimental study in rabbits

PURPOSE

Synthetic prosthetic materials that are fully absorbable seek to reduce the host foreign body reaction and promote host tissue regeneration. This preclinical trial was designed to analyse, in the long term, the behaviour of two prosthetic meshes, one synthetic and one composed of porcine collagen, in abdominal wall reconstruction.

METHODS

Partial defects were created in the abdominal walls of New Zealand rabbits and repaired using a synthetic absorbable mesh (Phasix™) or a non-crosslinked collagen bioprosthesis (Protexa™). After 3, 6, 12 and 18 months, specimens were recovered for light microscopy and collagen expression analysis to examine new host tissue incorporation, macrophage response and biomechanical strength.

RESULTS

Both materials showed good host tissue incorporation in line with their spatial structure. At 18 months postimplant, Protexa™ was highly reabsorbed while the biodegradation of Phasix™ was still incomplete. Collagenization of both materials was good. Macrophage counts steadily decreased over time in response to Phasix™, yet persisted in the collagen meshes. At 18 months, zones of loose tissue were observed at the implant site in the absence of herniation in both implant types. The stress-stretch behaviour of Phasix™ implants decreased over time, being more pronounced during the period of 12-18 months. Nevertheless, the abdominal wall repaired with Protexa™ became stiffer over time.

CONCLUSION

Eighteen months after the implant both materials showed good compatibility but the biodegradation of Phasix™ and Protexa™ was incomplete. No signs of hernia were observed at 18 months with the stress-stretch relations being similar for both implants, regardless of the more compliant abdominal wall repaired with Protexa™ at short term.

Poly-4-hydroxybutyrate (Phasix™) mesh onlay in complex abdominal wall repair

BACKGROUND

Poly-4-hydroxybutyric acid (P4HB, Phasix™) is a biosynthetic polymer that degrades by hydrolysis that can be woven into a mesh for use in soft tissue reinforcement. Herein, we describe our initial experience performing complex abdominal wall repair (CAWR) utilizing component separation and P4HB mesh as onlay reinforcement.

METHODS

All patients undergoing CAWR between June 2014 and May 2017 were followed prospectively for postoperative outcomes. Only those patients who underwent components separation with primary repair of the fascial edges followed by onlay of P4HB mesh were included in this study.

RESULTS

105 patients (52 male, 53 female; mean age 59.2 years, range 22-84) met inclusion criteria. Mean BMI was 29.1 (range 16-48); 52% patients had prior attempted hernia repair, most with multiple medical comorbidities (71% of patients with ASA 3 or greater). 30% of cases were not clean at the time of repair (CDC class 2 or greater). Median follow-up was 36 months (range 9-63). Eighteen patients (17%) developed a hernia recurrence ranging from 2 to 36 months postoperatively. Five (5%) patients developed a localized superficial infection treated with antibiotics, three (2.8%) required re-operation for non-healing wounds, and six (6%) patients developed seroma.

CONCLUSIONS

These data demonstrate a relatively low rate of hernia recurrence, seroma, and other common complications of CAWR in a highly morbid patient population. Importantly, the rate of mesh infection was low and no patients required complete mesh removal, even when placed into a contaminated or infected surgical field.

Comparison of Phasix, polypropylene, and primary closure of the abdominal donor site after bilateral free flap breast reconstruction: Long-term evaluation of abdominal hernia and bulge formation

BACKGROUND

Abdominal free flap harvest for breast reconstruction may result in significant morbidity in terms of hernias and bulges. Reinforcement of the donor site with mesh has been recommended to minimize the risk of hernias and bulges, but no studies exist evaluating the optimal type of mesh. Polypropylene has traditionally been used but the development of Phasix restorable mesh may be a reasonable alternative. Here, we compared the use of Phasix to polypropylene and primary closure and hypothesize that the former has lower rates of abdominal morbidity in the long term.

PATIENTS AND METHODS

A retrospective review of all patients undergoing bilateral free flap breast reconstruction from the abdomen was performed while patients with pedicle flaps or alternative donor sites were excluded. Patient demographics, medical/surgical history, cancer treatments, and flap type were analyzed. All patients were monitored for a minimum of 2 years for early donor site complications as well as hernia/bulges.

RESULTS

Sixty-six consecutive patients were included (40 patients with Phasix, 20 patients with polypropylene, and 6 patients with primary closure). Use of Phasix mesh resulted in higher initial operative costs ($2,750 vs. $72 vs. $0). Two patients with polypropylene mesh and one patient undergoing primary closure developed an abdominal bulge in an average follow-up of 25.2 months (11.5% vs. 0%, p = .04).

CONCLUSIONS

Mesh placement for abdominal wall reinforcement after bilateral free flap breast reconstruction minimizes the risk of hernias and bulges. Although Phasix results in increased initial costs, abdominal morbidity is significantly decreased after follow-up beyond 2 years.

Costs and Complications Associated with Infected Mesh for Ventral Hernia Repair

Background: Mesh hernia repair is widely accepted because of the associated reduction in hernia recurrence compared with suture-based repair. Despite initiatives to reduce risk, mesh infection and mesh removal are a significant challenge. In an era of healthcare value, it is essential to understand the global cost of care, including the incidence and cost of complications. The purpose of this study was to identify the outcomes and costs of care of patients who required the removal of infected hernia mesh. Methods: A review of databases from 2006 through June 2018 identified patients who underwent both ventral hernia repair (VHR) and re-operation for infected mesh removal. Patient demographic and operative details for both procedures, including age, Body Mass Index, mesh type, amount of time between procedures, and information regarding interval procedures were obtained. Clinical outcome measures were the length of the hospital stay, hospital re-admission, incision/non-incision complications, and re-operation. Hospital cost data were obtained from the cost accounting system and were combined with the clinical data for a cost and clinical representation of the cases. Results: Thirty-four patients underwent both VHR and removal of infected mesh material over the 12-year time frame and were included in the analyses; the average age at VHR was 48 years, and 16 patients (47%) were female. Following VHR, 21 patients (62%) experienced incision complications within 90 days post-operatively, the complications ranging from superficial surgical site infection (SSI) to evisceration. A mean of 22.65 months passed between procedures. After mesh removal, 16 patients (47%) experienced further incisional complications; and 22 (65%) patients had at least one re-admission. Eighteen patients (53%) required a minimum of one additional related operative procedure after mesh removal. Median hospital costs nearly doubled (p < 0.001) for the mesh removal ($23,841 [interquartile range {IQR} $13,596-$42,148]) compared with the VHR admission ($13,394 [IQR $8,424-$22,161]) not accounting for re-admission costs. A majority experienced hernia recurrence subsequent to mesh removal. Conclusions: Mesh infection after hernia repair is associated with significant morbidity and costs. Hospital re-admission, re-operations, and recurrences are common among these patients, resulting in greater healthcare resource utilization. Development of strategies to prevent mesh infection, identify patients most likely to experience infectious complications, and define best practices for the care of patients with mesh infection are needed.

Outcomes of Open Complex Ventral Hernia Repairs With Retromuscular Placement of Poly-4-Hydroxybutyrate Bioabsorbable Mesh

Purpose. Optimal technique and mesh selection still debated for complex ventral hernias. Limited data exists on bioabsorbable meshes in high-risk patients. We evaluated our experience. Methods. Retrospective review was conducted following institutional review board approval for ventral hernia repairs using a single bioabsorbable mesh between February 2014 and November 2017. Patient and hernia details characterized. Outcomes evaluated. Results. 20 ventral hernia repairs identified, 10 males, 10 females. Mean body mass index was 35 ± 7.4 kg/m², and mean age 47 ± 13 years. Comorbid conditions were diabetes 35% and hypertension 40%. Fifty-five percent had American Society of Anesthesiologist scores of 3. Hernia Characteristics: Ventral Hernia Working Group Grade 3 hernias were 80%, and remainder grade 2. Forty percent of hernias were Centers for Disease Control class III, and remainder were class I and II. The mean defect size was 533 cm² ± 500. Repair for prior open abdomens was 45%, recurrent hernias 20%, incisional 15%, incarcerated 10%, incisional with parastomal 5%, and primary ventral 5%. Concomitant bowel procedures in 8, (40%). All cases had retromuscular mesh placement (transversus abdominus release 65%, Rives-Stoppa 35%). Surgical site occurrences were 20% (surgical site infection 10%, seroma 10%). Overall hospital stay 5 ± 3 days. Ileus occurred in 20%. One postoperative death due to fatal arrhythmia. There were no recurrences with mean follow-up 21.1 months. Conclusions. Complex hernia repairs using bioabsorbable mesh were conducted in a small cohort of high-risk patients. These data demonstrate good outcomes with limited morbidity and mortality. There were no recurrences.

Non-Isothermal Crystallization Kinetics of Poly(4-Hydroxybutyrate) Biopolymer

The non-isothermal crystallization of the biodegradable poly(4-hydroxybutyrate) (P4HB) has been studied by means of differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). In the first case, Avrami, Ozawa, Mo, Cazé, and Friedman methodologies were applied. The isoconversional approach developed by Vyazovkin allowed also the determination of a secondary nucleation parameter of 2.10 × 105 K2 and estimating a temperature close to 10 °C for the maximum crystal growth rate. Similar values (i.e., 2.22 × 105 K2 and 9 °C) were evaluated from non-isothermal Avrami parameters. All experimental data corresponded to a limited region where the polymer crystallized according to a single regime. Negative and ringed spherulites were always obtained from the non-isothermal crystallization of P4HB from the melt. The texture of spherulites was dependent on the crystallization temperature, and specifically, the interring spacing decreased with the decrease of the crystallization temperature (Tc). Synchrotron data indicated that the thickness of the constitutive lamellae varied with the cooling rate, being deduced as a lamellar insertion mechanism that became more relevant when the cooling rate increased. POM non-isothermal measurements were also consistent with a single crystallization regime and provided direct measurements of the crystallization growth rate (G). Analysis of the POM data gave a secondary nucleation constant and a bell-shaped G-Tc dependence that was in relative agreement with DSC analysis. All non-isothermal data were finally compared with information derived from previous isothermal analyses.

Erratum: Addendum: Abdominal Wall Reconstruction: An Integrated Approach

[This corrects the article DOI: 10.1055/s-0038-1667062.].

A post-market, prospective, multi-center, single-arm clinical investigation of Phasix™ mesh for VHWG grade 3 midline incisional hernia repair: a research protocol

Background

Incisional heia is a frequent complication of midline laparotomy. The use of mesh in hernia repair has been reported to lead to fewer recurrences compared to primary repair. However, in Ventral Hernia Working Group (VHWG) Grade 3 hernia patients, whose hernia is potentially contaminated, synthetic mesh is prone to infection. There is a strong preference for resorbable biological mesh in contaminated fields, since it is more able to resist infection, and because it is fully resorbed, the chance of a foreign body reaction is reduced. However, when not crosslinked, biological resorbable mesh products tend to degrade too quickly to facilitate native cellular ingrowth. Phasix™ Mesh is a biosynthetic mesh with both the biocompatibility and resorbability of a biological mesh and the mechanical strength of a synthetic mesh. This multi-center single-arm study aims to collect data on safety and performance of Phasix™ Mesh in Grade 3 hernia patients.

Methods

A total of 85 VHWG Grade 3 hernia patients will be treated with Phasix™ Mesh in 15 sites across Europe. The primary outcome is Surgical Site Occurrence (SSO) including hematoma, seroma, infection, dehiscence and fistula formation (requiring intervention) through 3 months. Secondary outcomes include recurrence, infection and quality of life related outcomes after 24 months. Follow-up visits will be at drain removal (if drains were not placed, then on discharge or staple removal instead) and in the 1st, 3rd, 6th, 12th, 18th and 24th month after surgery.

Conclusion

Based on evidence from this clinical study Depending on the results this clinical study will yield, Phasix™ Mesh may become a preferred treatment option in VHWG Grade 3 patients.

Trial registration

The trial was registered on March 25, 2016 on clinicaltrials.gov: NCT02720042.

Prophylactic mesh augmentation: Patient selection, techniques, and early outcomes

BACKGROUND

Incisional hernias (IH) following abdominal surgery are frequent and morbid. Prophylactic mesh augmentation (PMA) has emerged as a technique to reduce IH formation. We aim to report patient selection, techniques and early outcomes after PMA.

METHODS

Retrospective chart review identified descriptive characteristics, risk factors, operative technique, and early post-operative outcomes for PMA patients and matched non-PMA patients between January 1, 2016 and October 31, 2017.

RESULTS

18 consecutive PMA cases were performed (55.6% female, mean age 54.3 years and mean BMI = 29.5 kg/m²). 88.9% of patients had at least two high-risk features for IH. Zero PMA patients developed IH compared to 5.3% non-PMA patients (p = 0.314) (6-months mean follow-up). No difference in surgical site occurrences (SSO) were identified between the two groups.

CONCLUSIONS

Early results are encouraging, demonstrating PMA is safe with equivocal SSO. Further studies are needed to assess if the reduction in IH formation is statistically significant with longer follow-up.