Comparison of Synthetic and Biologic Mesh in Ventral Hernia Repair Using Components Separation Technique

Postoperative bleeding after complex abdominal wall reconstruction: A post hoc analysis of a randomized clinical trial

BACKGROUND

Abdominal wall reconstruction requires extensive dissection of the abdominal wall, exposure of the retroperitoneum, and aggressive chemoprophylaxis to reduce the risk of thromboembolic complications. The need for early anticoagulation puts patients at risk for bleeding. We aimed to quantify postoperative blood loss, incidence of transfusion and reoperation, and associated risk factors in patients undergoing complex abdominal wall reconstruction.

METHODS

All patients underwent a posterior component separation with transversus abdominis release and placement of retromuscular mesh for ventral hernias <20 cm wide and were enrolled in a clinical trial assessing the utility of trans-fascial mesh fixation. A post hoc analysis was performed to quantify postoperative hemoglobin drop, blood transfusions, and procedural interventions for ongoing bleeding during the first 30 postoperative days. Multivariate logistic regression was used to identify predictors of transfusion.

RESULTS

In 325 patients, hemoglobin decreased by 3.61 (±1.58) g/dL postoperatively. Transfusion incidence was 9.5% (n = 31), and 3.1% (n = 10) required a surgical intervention for bleeding. Initiation of therapeutic anticoagulation postoperatively resulted in a higher likelihood of requiring surgical intervention for bleeding (odds ratio 10.4 [95% confidence interval 2.75-43.8], P < .01). Use of perioperative therapeutic anticoagulation was associated with higher rates of transfusion (odds ratio 3.51 [95% confidence interval 1.34-8.53], P < .01). Neither intraoperative blood loss nor operative times were associated with an increased transfusion requirement or need for operative intervention.

CONCLUSION

Patients undergoing transversus abdominis release are at a high risk of postoperative bleeding that can require transfusion and reoperation. Patients requiring postoperative therapeutic anticoagulation are at particularly high risk.

The outcomes of open anterior component separation versus posterior component separation with transversus abdominis release for complex incisional hernias: a systematic review and meta-analysis

PURPOSE

The main objective was to assess the prevalence of hernia recurrence, wound complications (surgical site infections [SSI], seroma and hematoma) and mortality after anterior component separation (ACS) and posterior component separation via transversus abdominis muscle release (PCSTAR) in patients with complex incisional hernias. The so-called complex IH is a serious medical and societal challenge due to its direct and indirect costs; it is also hampered by the use of different surgical techniques, different type of meshes, and different results heterogeneously reported and interpreted. According to actual data, the best approach seems to be a mesh reinforcement component separation procedure augmented or not with an adjuvant technique (preoperative progressive pneumoperitoneum and/or Botulin toxin type A infiltration).

METHODS

A systematic search of four databases (MEDLINE, PubMed, Web of Science, and Google Scholars) was conducted to identify studies reporting on outcomes of component separation techniques and which were published before December 2021. A systematic review and a meta-analysis of postoperative outcomes were performed.

RESULTS

Nineteen studies including 3412 patients (1709 with ACS and 1703 with PCSTAR) were selected. Pooled hernia recurrence rate after a minimum 1-year follow-up was evaluated at 5.15% (odds ratio [OR] 0.68; 95% confidence interval [CI] 0.5-0.9; p = 0.0175). Pooled surgical site infection rate was 10.6% (OR 1.32; 95% CI 1.06-1.65; p = 0.0119). Seroma and hematoma were estimated at 9.75% (OR 1.93; 95% CI 1.52-2.44; p = 0.0001) and 3.83% (OR 1.81; 95% CI 1.26-2.61; p = 0.0012), respectively. ACS was associated with increased wound morbidity, seroma and hematoma. PCSTAR displayed higher recurrence rate (4.27% vs 6.11%).

CONCLUSIONS

PCSTAR was superior to ACS in terms of wound morbidity, surgical site infections, seroma and hematoma incidence. The procedure should be further evaluated in comparative head-to-head randomized controlled trials.

Platelet rich plasma concentration improves biologic mesh incorporation and decreases multinucleated giant cells in a dose dependent fashion

Platelet rich plasma (PRP) has been shown to improve incorporation and reduce inflammation in ventral hernia repair (VHR) with acellular dermal matrix (ADM). The concentration of platelets in PRP varies in clinical studies and an ideal concentration has yet to be defined. The effects of varied concentrations of PRP on ADM incorporation and inflammatory cell infiltration in a rat model of VHR. We hypothesized that increasing concentration of PRP would lead to improved incorporation, decreased CD8+ and multinucleated giant cell (MNGC) infiltrate. Lewis rats underwent ventral hernia creation and repair 30 days later with porcine non-crosslinked ADM. PRP was applied to the mesh prior to skin closure at concentrations of 1 × 104 plt/μL (PRP-LOW), 1 × 106 plt/μL (PRP-MID), or 1 × 107 plt/μL (PRP-HIGH) and tissue harvested at 2 and 4 weeks. Cellularization, tissue deposition, and mesh thickness using hematoxylin and eosin and Masson's trichrome, and neovascularization was assessed with VVG staining, to establish the relationship of PRP concentration to metrics of incorporation. MNGC and CD8+ T-cell infiltration were quantified to establish the relationship of inflammatory cell infiltration in response to PRP concentration. Lymphocyte infiltration was assessed using immunohistochemical staining for CD8. PRP-HIGH treated had significantly greater tissue deposition at 4 weeks. PRP-MID showed increasing mesh thickness at 2 weeks. Cell infiltration was significantly higher with PRP-HIGH at both 2 and 4 weeks while PRP-LOW showed increased cell infiltration only at 4 weeks. At both time points there was a trend towards a dose dependent response in cell infiltration to PRP concentration. Neovascularization was highest with MID-plt at 2 weeks, yet no significant differences were noted compared to controls. CD8+ cell infiltrate was significantly decreased at 2 and 4 weeks in PRP-LOW and PRP-MID treated groups. PRP at all concentrations significantly decreased MNGC infiltration at 2 weeks while only PRP-HIGH and PRP-MID had significant reductions in MNGC at 4 weeks. Both MNGC and CD8+ cell infiltration demonstrated dose dependent reduction in relation to PRP concentration. Increasing platelet concentrations of PRP correlated with improved incorporation, tissue deposition, and decreased scaffold degradation. These findings were associated with a blunted foreign body response. These findings suggest PRP reduces inflammation which may be beneficial for ADM incorporation in VHR.

Early outcomes of component separation techniques: an analysis of the Spanish registry of incisional Hernia (EVEREG)

AIM

To analyze the outcomes of component separation techniques (CST) to treat incisional hernias (IH) in a large multicenter cohort of patients.

METHODS

All IH repair using CST, registered in EVEREG from July 2012 to December 2019, were included. Data on the pre-operative patient characteristics and comorbidities, IH characteristics, surgical technique, complications, and recurrence were collected. Outcomes between anterior (ACS) and posterior component separation (PCS) techniques were compared. Risk factors for complications and recurrences were analyzed.

RESULTS

During the study period, 1536 patients underwent CST (45.5% females) with a median age of 64.0 years and median body mass index (BMI) of 29.7 kg/m². ACS was the most common technique (77.7%). Overall complications were frequent in both ACS and PCS techniques (36.5%), with a higher frequency of wound infection (10.6% vs. 7.0%; P = 0.05) and skin necrosis (4.4% vs. 0.1%; P < 0.0001) with the ACS technique. Main factors leading to major complications were mesh explant (OR 1.72; P = 0.001), previous repair (OR 0.75; P = 0.038), morbid obesity (OR 0.67; P = 0.015), ASA grade (OR 0.62; P < 0.0001), COPD (OR 0.52; P < 0.0001), and longitudinal diameter larger than 10 cm (OR 0.58; P = 0.001). After a minimum follow-up of 6 months (median 15 months; N = 590), 59 (10.0%) recurrences were diagnosed. Operations performed in a non-specialized unit were significantly associated with recurrences (HR 4.903, CI 1.64-14.65; P = 0.004).

CONCLUSION

CST is a complex procedure with a high rate of complications. Both ACS and PCS techniques have similar complication and recurrence rates. Operations performed in a specialized unit have better outcomes.

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.

Early versus delayed complex abdominal wall reconstruction with biologic mesh following damage-control surgery

BACKGROUND

Damage-control surgery for trauma and intra-abdominal catastrophe is associated with a high rate of morbidities and postoperative complications. This study aimed to compare the outcomes of patients undergoing early complex abdominal wall reconstruction (e-CAWR) in acute settings versus those undergoing delayed complex abdominal wall reconstruction (d-CAWR).

METHOD

This study was a pooled analysis derived from the retrospective and prospective database between the years 2013 and 2019. The outcomes were compared for differences in demographics, presentation, intraoperative variables, Ventral Hernia Working Grade (VHWG), US Centers for Disease Control and Prevention wound class, American Society of Anesthesiologists (ASA) scores, postoperative complications, hospital length of stay, and readmission rates. We performed Student's t test, χ2 test, and Fisher's exact test to compare variables of interest. Multivariable linear regression model was built to evaluate the association of hospital length of stay and all other variables including the timing of complex abdominal wall reconstruction (CAWR). A p value of <0.05 was considered significant.

RESULTS

Of the 236 patients who underwent CAWR with biological mesh, 79 (33.5%) had e-CAWR. There were 45 males (57%) and 34 females (43%) in the e-CAWR group. The ASA scores of IV and V, and VHWG grades III and IV were significantly more frequent in the e-CAWR group compared with the d-CAWR one. Postoperatively, the incidence of surgical site occurrence, Clavien-Dindo complications, comprehensive complication index, unplanned reoperations, and mortality were similar between the two groups. Backward linear regression model showed that the timing of CAWR (β = -11.29, p < 0.0001), ASA (β = 3.98, p = 0.006), VHWG classification (β = 3.62, p = 0.015), drug abuse (β = 13.47, p = 0.009), and two comorbidities of cirrhosis (β = 12.34, p = 0.001) and malignancy (β = 7.91, p = 0.008) were the significant predictors of the hospital length of stay left in the model.

CONCLUSION

Early CAWR led to shorter hospital length of stay compared with d-CAWR in multivariable regression model.

LEVEL OF EVIDENCE

Therapeutic, level IV.

What Exactly is Meant by "Loss of Domain" for Ventral Hernia? Systematic Review of Definitions

Large ventral hernias are a significant surgical challenge. "Loss of domain" (LOD) expresses the relationship between hernia and abdominal volume, and is used to predict operative difficulty and success. This systematic review assessed whether different definitions of LOD are used in the literature. The PubMed database was searched for articles reporting large hernia repairs that explicitly described LOD. Two reviewers screened citations and extracted data from selected articles, focusing on the definitions used for LOD, study demographics, study design, and reporting surgical specialty. One hundred and seven articles were identified, 93 full-texts examined, and 77 were included in the systematic review. Sixty-seven articles were from the primary literature, and 10 articles were from the secondary literature. Twenty-eight articles (36%) gave a written definition for loss of domain. These varied and divided into six broad groupings; four described the loss of the right of domain, six described abdominal strap muscle contraction, five described the "second abdomen", five describing large irreducible hernias. Six gave miscellaneous definitions. Two articles gave multiple definitions. Twenty articles (26%) gave volumetric definitions; eight used the Tanaka method [hernia sac volume (HSV)/abdominal cavity volume] and five used the Sabbagh method [(HSV)/total peritoneal volume]. The definitions used for loss of domain were not dependent on the reporting specialty. Our systematic review revealed that multiple definitions of loss of domain are being used. These vary and are not interchangeable. Expert consensus on this matter is necessary to standardise this important concept for hernia surgeons.

Resistance of Synthetic and Biologic Surgical Meshes to Methicillin-Resistant Staphylococcus aureus Biofilm: An In Vitro Investigation

Surgical meshes have become the standard procedure for a variety of surgical applications with 20 million meshes being implanted each year. The popularity of mesh usage among surgeons is backed by the multiple studies that support its functionality as a tool for improving surgical outcomes. However, their use has also been associated with infectious surgical complications and many surgeons have turned to biologic meshes. While there have been several studies investigating synthetic meshes, there is limited data comparing synthetic and biologic meshes in vitro in an infection model. This study evaluates the in vitro susceptibility of both synthetic and biologic meshes to single-species methicillin-resistant Staphylococcus aureus (MRSA) biofilms. This research compares biofilm biomass, average thickness, and coverage between the three meshes through florescent in situ hybridization (FISH), confocal scanning microscopy (CSLM), and image analysis. We also report the varying levels of planktonic and attached bacteria through sonication and cfu counts. While the data illustrates increased biofilm formation on biologic mesh in vitro, the study must further be investigated in vivo to confirm the study observations.

Quality measures in ventral hernia repair: a systematic review

BACKGROUND

The US healthcare system is shifting towards reimbursement for quality over quantity of care. Quality measures are tied to financial incentives in these healthcare models. It is important that surgeons become familiar with quality measures addressing ventral hernia repair and understand candidate measures that may drive future quality measure development.

STUDY DESIGN

We performed a systematic review of society websites, quality measure databases, and the literature (Pubmed, Embase/Scopus, and Google Scholar) for quality measures addressing ventral hernia surgery. Clinical practice guidelines were included as candidate quality measures. All measures were categorized as structure, process or outcome according to Donabedian domains, as well as within the six National Quality Strategy (NQS) domains.

RESULTS

Thirty quality measures and candidate measures were identified. Eight candidate measures from the American Hernia Society addressed ventral hernia repair, and 22 quality measures in general surgery were also relevant to ventral hernia repair. Of the candidate measures, 6 (75%) were outcome and 2 (25%) were process measures. Of existing general surgery quality measures, 9 (41%) were outcome and 13 (59%) were process measures. No structural measures were identified. Overall, the majority of measures addressed NQS priorities of effective clinical care (33%) and patient safety (27%), while few addressed other domains.

CONCLUSION

Both the Donabedian domains of quality and NQS priorities were unequally represented in the current measures addressing ventral hernia repair. Recognizing and addressing the under-represented areas will provide a more balanced framework for developing quality measures and ensure that ventral hernia surgery is appropriately evaluated in value-based payment models.

Biological Implant for Complex Abdominal Wall Reconstruction: A Single Institution Experience and Review of Literature

AIM

To present our single institution and surgeon's complex abdominal wall reconstructions (CAWR) experience with Permacol™ mesh through a non-randomized study.

PATIENTS AND METHOD

Data of 51 consecutive patients were prospectively collected between 2003 and 2015. Patients had a median of 3 comorbidities (range 0-10) and 68% were Center for Disease Control class II-IV. The mean previous repair was 1.3 (range, 0-12), and 25 (44%) had a mesh in situ. The median defect size was 625 cm².

RESULTS

Among the 56 CAWR procedures, in 16 (29%) bowel resection/anastomosis was performed. The overall post-operative complication rate was 45%, and it was wound-related except from 1 patient dead for myocardial infarction. One was lost at follow-up. Five were re-operated for recurrence with a second Permacol mesh, leading to 14 (26%) overall recurrences at a mean follow-up of 44 months (range, 4-123). In 33 (59%) cases, fascial closure was achieved. The mesh placement was intraperitoneal in 89%, retro-muscular in 9% and supra-fascial in 1% of cases. A multivariate analysis showed that predictor risk for recurrence was more than 3 previous repairs, wound class III-IV, whereas age, type of comorbidities, defect size and fascial closure did not influence the recurrence. Median post-operative performance status was 0 (range; 0-3). A satisfaction questionnaire was obtained in 43 patients, and 86% of them were satisfied with the outcome.

CONCLUSIONS

Biological materials have the potential to reduce morbidity and improve outcome of definitive repair of CAWR.

What is the evidence for the use of biologic or biosynthetic meshes in abdominal wall reconstruction?

INTRODUCTION

Although many surgeons have adopted the use of biologic and biosynthetic meshes in complex abdominal wall hernia repair, others have questioned the use of these products. Criticism is addressed in several review articles on the poor standard of studies reporting on the use of biologic meshes for different abdominal wall repairs. The aim of this consensus review is to conduct an evidence-based analysis of the efficacy of biologic and biosynthetic meshes in predefined clinical situations.

METHODS

A European working group, "BioMesh Study Group", composed of invited surgeons with a special interest in surgical meshes, formulated key questions, and forwarded them for processing in subgroups. In January 2016, a workshop was held in Berlin where the findings were presented, discussed, and voted on for consensus. Findings were set out in writing by the subgroups followed by consensus being reached. For the review, 114 studies and background analyses were used.

RESULTS

The cumulative data regarding biologic mesh under contaminated conditions do not support the claim that it is better than synthetic mesh. Biologic mesh use should be avoided when bridging is needed. In inguinal hernia repair biologic and biosynthetic meshes do not have a clear advantage over the synthetic meshes. For prevention of incisional or parastomal hernias, there is no evidence to support the use of biologic/biosynthetic meshes. In complex abdominal wall hernia repairs (incarcerated hernia, parastomal hernia, infected mesh, open abdomen, enterocutaneous fistula, and component separation technique), biologic and biosynthetic meshes do not provide a superior alternative to synthetic meshes.

CONCLUSION

The routine use of biologic and biosynthetic meshes cannot be recommended.

Comparison of biological and alloplastic meshes in ventral incisional hernia repair

PURPOSE

The aim of our retrospective analysis was to compare the results of incisional hernia repair by porcine small intestinal submucosa-derived (SIS) meshes with those obtained by alloplastic polypropylene-based (PP) meshes in comparable surgical indications by matched-pair design. We hypothesized that in incisional hernia, SIS mesh repair is associated with fewer recurrences and SSO than PP mesh repair in incisional hernias.

METHODS

Twenty-four matched pairs (SIS vs. PP mesh repair between 1 January 2005 and 31 December 2013) were identified by matching criteria: gender, age, comorbidities, body mass index, EHS hernia classification, mesh implantation technique, CDC wound classification, and source of contamination/primary surgery leading to incisional hernia. Minimal follow-up time was 24 months. Means and standard deviations were compared by paired t test; categorial data were compared by McNemar's test. Poisson's distribution and negative binominal distribution were employed to detect significant correlation.

RESULTS

There were no statistically significant differences between both groups in the pre- and perioperative factors and the follow-up times. There were significantly more wound complications (19 vs. 12, p = 0.041), longer hospital stay (22.0 ± 6.3 vs. 12.0 ± 3.1 days, p = 0.010), and significantly more recurrent hernias (25 vs. 12.5%, p = 0.004) after SIS mesh repair. Both the Poisson's distribution and the negative binominal distribution unveiled significantly more complication points (3-6 vs. 1-2) per month after SIS mesh repair.

CONCLUSION

There is no advantage of SIS meshes compared to PP meshes in incisional hernia repair with different degrees of wound contamination in this matched-pair analysis. Further prospective and randomized trials or at least registry studies such as the EHS register with standardized and defined conditions are warranted.

Initial Experience With Biologic Polymer Scaffold (Poly-4-hydroxybuturate) in Complex Abdominal Wall Reconstruction

OBJECTIVE

To evaluate the use of the new absorbable polymer scaffold poly-4-hydroxybutyrate (P4HB) in complex abdominal wall reconstruction.

BACKGROUND

Complex abdominal wall reconstruction has witnessed tremendous success in the last decade after the introduction of cadaveric biologic scaffolds. However, the use of cadaveric biologic mesh has been expensive and plagued by complications such as seroma, infection, and recurrent hernia. Despite widespread application of cadaveric biologic mesh, little data exist on the superiority of these materials in the setting of high-risk wounds in patients. P4HB, an absorbable polymer scaffold, may present a new alternative to these cadaveric biologic grafts.

METHODS

A retrospective analysis of our initial experience with the absorbable polymer scaffold P4HB compared with a consecutive contiguous group treated with porcine cadaveric mesh for complex abdominal wall reconstructions. Our analysis was performed using SAS 9.3 and Stata 12.

RESULTS

The P4HB group (n = 31) experienced shorter drain time (10.0 vs 14.3 d; P < 0.002), fewer complications (22.6% vs 40.5%; P < 0.046), and reherniation (6.5% vs 23.8%; P < 0.049) than the porcine cadaveric mesh group (n = 42). Multivariate analysis for infection identified: porcine cadaveric mesh odds ratio 2.82, length of stay odds ratio 1.11; complications: drinker odds ratio 6.52, porcine cadaveric mesh odds ratio 4.03, African American odds ratio 3.08, length of stay odds ratio 1.11; and hernia recurrence: porcine cadaveric mesh odds ratio 5.18, drinker odds ratio 3.62, African American odds ratio 0.24. Cost analysis identified that P4HB had a $7328.91 financial advantage in initial hospitalization and $2241.17 in the 90-day postdischarge global period resulting in $9570.07 per case advantage over porcine cadaveric mesh.

CONCLUSIONS

In our early clinical experience with the absorbable polymer matrix scaffold P4HB, it seemed to provide superior clinical performance and value-based benefit compared with porcine cadaveric biologic mesh.

Biomimetic collagen/elastin meshes for ventral hernia repair in a rat model

Ventral hernia repair remains a major clinical need. Herein, we formulated a type I collagen/elastin crosslinked blend (CollE) for the fabrication of biomimetic meshes for ventral hernia repair. To evaluate the effect of architecture on the performance of the implants, CollE was formulated both as flat sheets (CollE Sheets) and porous scaffolds (CollE Scaffolds). The morphology, hydrophylicity and in vitro degradation were assessed by SEM, water contact angle and differential scanning calorimetry, respectively. The stiffness of the meshes was determined using a constant stretch rate uniaxial tensile test, and compared to that of native tissue. CollE Sheets and Scaffolds were tested in vitro with human bone marrow-derived mesenchymal stem cells (h-BM-MSC), and finally implanted in a rat ventral hernia model. Neovascularization and tissue regeneration within the implants was evaluated at 6weeks, by histology, immunofluorescence, and q-PCR. It was found that CollE Sheets and Scaffolds were not only biomechanically sturdy enough to provide immediate repair of the hernia defect, but also promoted tissue restoration in only 6weeks. In fact, the presence of elastin enhanced the neovascularization in both sheets and scaffolds. Overall, CollE Scaffolds displayed mechanical properties more closely resembling those of native tissue, and induced higher gene expression of the entire marker genes tested, associated with de novo matrix deposition, angiogenesis, adipogenesis and skeletal muscles, compared to CollE Sheets. Altogether, this data suggests that the improved mechanical properties and bioactivity of CollE Sheets and Scaffolds make them valuable candidates for applications of ventral hernia repair.

STATEMENT OF SIGNIFICANCE

Due to the elevated annual number of ventral hernia repair in the US, the lack of successful grafts, the design of innovative biomimetic meshes has become a prime focus in tissue engineering, to promote the repair of the abdominal wall, avoid recurrence. Our meshes (CollE Sheets and Scaffolds) not only showed promising mechanical performance, but also allowed for an efficient neovascularization, resulting in new adipose and muscle tissue formation within the implant, in only 6weeks. In addition, our meshes allowed for the use of the same surgical procedure utilized in clinical practice, with the commercially available grafts. This study represents a significant step in the design of bioactive acellular off-the-shelf biomimetic meshes for ventral hernia repair.