Ventral herniorrhaphy: experience with two different biosynthetic mesh materials, Surgisis and Alloderm

Nanotechnology approaches in abdominal wall reconstruction: A narrative review about scaffold and meshes

Repairing abdominal wall defects poses challenges for surgeons. Although mesh reinforcement is commonly used for primary repair, nanotechnology has emerged as a promising approach for developing innovative repair techniques. Most research in this area focuses on fabricating scaffolds designed specifically for abdominal wall repair, particularly in cases of hernia. These scaffolds are engineered to replicate the structure and function of the native extracellular matrix. This review aimed to summarize the existing studies on the application of nanotechnology in abdominal wall reconstruction following injury or repair.

A multicenter randomized controlled trial comparing short- and medium-term outcomes of novel biologics and lightweight synthetic mesh for laparoscopic inguinal hernia repair

INTRODUCTION

The use of biological graft in laparoscopic inguinal hernia repair (LIHR) has been controversial, and there is a lack of high-level evidence to confirm the value of biological graft in LIHR. The purpose of this study is to evaluate the effectiveness of a novel composite biologics in LIHR.

METHODS

A multicenter, single-blinded, randomized controlled clinical trial was designed. Fifty patients with unilateral primary inguinal hernia were randomly assigned to the experimental and control group (1:1). The experimental group was repaired with a non-crosslinked composite extracellular matrix from porcine urinary bladder matrix and small intestinal submucosa (UBM/SIS). The control group was repaired with a lightweight, large-pore, synthetic mesh. The primary endpoint was the effectiveness rate of hernia repair.

RESULTS

The patients were followed up for four years. No significant difference was found between the experimental group and the control group in the effective rate of hernia repair (24/24[100%] vs 21/22[95.45%], RR, 0.4667; 95%CI, 0.3294-2.304; P = 0.4783). There was no fever, seroma, infection, groin pain, foreign body discomfort or recurrence in the experimental group during the follow-up. In the control group, there were 2 cases of seroma 14 days after operation, 1 case of groin discomfort 60 days after operation and one case of recurrence 410 days after surgery.

CONCLUSION

Compared with the lightweight synthetic mesh, the novel UBM/SIS graft has comparable short-term and medium-term effectiveness in LIHR, and the incidence of postoperative complications such as seroma groin discomfort is lower. Trial registration Clinical Trials Registry: ChiCTR1800020173.

Patches in Congenital Diaphragmatic Hernia: Systematic Review

OBJECTIVE

This systematic review aims to evaluate current choices in practice and outcomes of biomaterials used in patch repair of congenital diaphragmatic hernia (CDH).

BACKGROUND

Multiple biomaterials, both novel and combinations of pre-existing materials are employed in patch repair of large size CDHs.

METHODS

A literature search was performed across Embase, Medline, Scopus, and Web of Science. Publications that explicitly reported patch repair, material used, and recurrences following CDH repair were selected.

RESULTS

Sixty-three papers were included, presenting data on 4595 patients, of which 1803 (39.2%) were managed using 19 types of patches. Goretex® (GTX) (n=1106) was the most frequently employed patch followed by Dualmesh® (n=267), Surgisis® (n=156), Marlex®/GTX® (n=56), Tutoplast dura® (n=40), Dacron® (n=34), Dacron®/GTX® (n=32), Permacol® (n=24), Teflon® (n=24), Surgisis®/GTX® (n=15), Sauvage® Filamentous Fabric (n=13), Marlex® (n=9), Alloderm® (n=8), Silastic® (n=4), Collagen coated Vicryl® mesh (CCVM) (n=1), Mersilene® (n=1), and MatriStem® (n=1) Biomaterials were further subgrouped as: synthetic nonresorbable (SNOR) (n=1458), natural resorbable (NR) (n=241), combined natural and synthetic nonresorbable (NSNOR) (n=103), and combined natural and synthetic resorbable (NSR) (n=1). The overall recurrence rate for patch repair was 16.6% (n=299). For patch types with n>20, recurrence rate was lowest in GTX/Marlex (3.6%), followed by Teflon (4.2%), Dacron (5.6%), Dualmesh (12.4%), GTX (14.8%), Permacol (16.0%), Tutoplast Dura (17.5%), SIS/GTX (26.7%), SIS (34.6%), and Dacron/GTX (37.5%).When analyzed by biomaterial groups, recurrence was highest in NSR (100%), followed by NR (31.5%), NSNOR (17.5%), and SNOR the least (14.0%).

CONCLUSION

In this cohort, over one-third of CDH were closed using patches. To date, 19 patch types/variations have been employed for CDH closure. GTX is the most popular, employed in over 60% of patients; however, excluding smaller cohorts (n<20), GTX/Marlex is associated with the lowest recurrence rate (3.6%). SNOR was the material type least associated with recurrence, while NSR experienced recurrence in every instance.

Biosynthetic meshes in contaminated fields: where are we now? A systematic review and meta-analysis in humans

PURPOSE

Selection of an appropriate mesh reinforcement for hernia repair in contaminated fields is a significant problem for surgeons. To date the proper mesh for contaminated fields has not been found. Biosynthetic meshes have emerged as new treatment option in contaminated fields. This study aims to evaluate the postoperative outcomes of biosynthetic meshes in contaminated fields.

METHODS

Systematic electronic search (PubMed, Medline, Embase, Scopus), according to PRISMA criteria, was performed. A literature search of scientific papers was performed by two reviewers until April 2021. Articles were chosen based on reference to biosynthetic meshes, their use in infected fields, and in human subjects. GRADE methodology and the modified Newcastle-Ottawa scale were used to assess the quality of studies. According to CDC-Centers for Disease Control classes patients were divided into two subgroups, group 1 (CDC class 2) and group 2 (CDC classes 3-4).

RESULTS

The research included 21 articles and 1619 patients were analyzed. Long-term follow-up showed a significant higher recurrence rate than short-term follow-up. P < 0.001. Meta-analysis of these studies showed that the SSI were significantly higher in CDC classes 3-4 than CDC class 2 (P < 0.01). No differences were found in SSO (P = 0.06) and recurrence (P = 0.37) rate among the two groups. Phasix™ was the most common mesh in 15 studies. The mean follow-up was 23.0 months. The surgical site infection (SSI) rate was 17.3%. The surgical site occurrence (SSO) rate was 32.4%. Recurrence rate was 11.5%.

CONCLUSION

This is the first systematic review and meta-analysis on the clinical outcomes of abdominal wall repair using biosynthetic mesh in contaminated-infected settings. The results show good results in patients at high risk of postoperative wound complications. The aim of this study is to add to the growing literature on biosynthetic mesh a picture of current literature evidence to help future researchers performing further studies on this topic.

Acellular dermal matrix in reconstructive surgery: Applications, benefits, and cost

Modern tissue engineering has made substantial advancements that have revolutionized plastic surgery. Acellular dermal matrix (ADM) is an example that has gained considerable attention recently. ADM can be made from humans, bovines, or porcine tissues. ADM acts as a scaffold that incorporates into the recipient tissue. It is gradually infiltrated by fibroblasts and vascularized. Fortunately, many techniques have been used to remove cellular and antigenic components from ADM to minimize immune system rejection. ADM is made of collagen, fibronectin, elastin, laminin, glycosaminoglycans, and hyaluronic acid. It is used in critical wounds (e.g., diabetic wounds) to protect soft tissue and accelerate wound healing. It is also used in implant-based breast reconstruction surgery to improve aesthetic outcomes and reduce capsule contracture risk. ADM has also gained attention in abdominal and chest wall defects. Some studies have shown that ADM is associated with less erosion and infection in abdominal hernias than synthetic meshes. However, its higher cost prevents it from being commonly used in hernia repair. Also, using ADM in tendon repair (e.g., Achilles tendon) has been associated with increased stability and reduced rejection rate. Despite its advantages, ADM might result in complications such as hematoma, seroma, necrosis, and infection. Moreover, ADM is expensive, making it an unsuitable option for many patients. Finally, the literature on ADM is insufficient, and more research on the results of ADM usage in surgeries is needed. This article aims to review the literature regarding the application, Benefits, and costs of ADM in reconstructive surgery.

Synthetic versus Biological Patches for CDH: A Comparison of Recurrence Rates and Adverse Events, Systematic Review, and Meta-Analysis

OBJECTIVE

 Our systematic review aims to compare recurrence rates and complications of biological versus synthetic patches for the repair of congenital diaphragmatic herniae.

METHODS

 Studies from January 1, 1980 to April 25, 2020, with patients under the age of 16 years and with a minimum 6-month follow-up, were included from MEDLINE, Embase, and Cochrane databases. Funnel plots for recurrence rates were constructed for biological and synthetic patches. Subgroup analysis was performed for recurrence rate at the 1-year time-point and data were gathered on individual adverse events from relevant studies.

RESULTS

 A total of 47 studies with 986 patients (226 biological, 760 synthetic) were included. Funnel plot analysis determined overall recurrence rates of 16.7% for synthetic and 30.3% for biological patches. Subgroup analysis of 493 and 146 patients with synthetic and biological patches, respectively, showed recurrence rates of 9.9 and 26%, respectively.The most commonly used patch types-PTFE (polytetrafluoroethylene) and SIS (small intestinal submucosa)-had 11.5 and 33.3% recurrence, respectively. Adhesive bowel obstruction rates ranged from 4 to 29% in studies that systematically reported it for synthetic, and 7 to 35% for biological patches. Gastroesophageal reflux rates ranged from 25 to 48% in studies that systematically reported it for synthetic, and 21 to 42% for biological patches. Pectus deformity rates were reported as high as 80% for synthetic patches.

CONCLUSION

 Biological patches appear to have higher recurrence rates than synthetic patches, while skeletal deformities are associated more commonly with synthetic patches. Results of biological patches are mainly using SIS and this may overestimate complications of current superior biological patches.

Comparison of outcomes of ventral hernia repair using different meshes: a systematic review and network meta-analysis

PURPOSE

We conducted a network meta-analysis to evaluate potential differences in patient outcomes when different meshes, especially biological meshes, were used for ventral hernia repair.

METHODS

PubMed, Embase, Cochrane Library, and Clinical Trials.gov databases were searched for studies comparing biological meshes with biological or synthetic meshes for ventral hernia repair. The outcomes were hernia recurrence rate, surgical site infection, and seroma. We performed a two-step network meta-analysis to investigate the outcomes of several biological meshes: non-cross-linked human acellular dermal matrix (NCHADM), non-cross-linked porcine ADM (NCPADM), non-cross-linked bovine ADM (NCBADM), cross-linked porcine ADM (CPADM), and porcine small intestinal submucosa (PSIS).

RESULTS

From 6304 publications, 23 studies involving 2603 patients were finally included. We found no differences between meshes in recurrence at 1-year follow-up and in surgical site infection rate. NCBADM was associated with the lowest recurrence rate and the lowest surgical site infection rate. NCHADM implantation was associated with the lowest rate of seroma. PSIS was associated with a higher risk of seroma than NCHADM (pooled risk ratio 3.89, 95% confidence interval 1.13-13.39) and NCPADM (RR 3.42, 95% CI 1.29-9.06).

CONCLUSIONS

Our network meta-analysis found no differences in recurrence rate or surgical site infection among different biological meshes. The incidence of postoperative seroma was higher with PSIS than with acellular dermal matrices. We observed large heterogeneity in the studies of ventral hernia repair using biological meshes, and, therefore, well-designed randomized clinical trials are needed.

The Case for Onlay Biologic Mesh in Abdominal Wall Reconstruction Using Progressive Tension Suture Fixation

BACKGROUND

After many years of debate, underlay and sublay placement of mesh slowly emerged as the standard of care in abdominal wall reconstruction because of lower hernia recurrence rates. However, onlay has the advantages of being faster, less invasive, and technically easier compared with underlay and sublay. Therefore, if a similar recurrence could be achieved, then onlay should be a consideration. In this study, we present a new onlay method using multipoint progressive tension suture fixation.

METHODS

This was a retrospective chart review of patients who underwent abdominal wall reconstruction from 2012 to 2019. Inclusion criteria included onlay mesh placement and at least 1 year of follow-up. The core principles of the surgical technique are establishing myofascial continuity by component separation and reinforcing the repair with onlay mesh that is fixated with multipoint progressive tension sutures.

RESULTS

The number of patients after exclusions was 59, and the average body mass index was 32.52 ± 6.44 kg/m2. More than half (62.7%) of patients had a history of hypertension, 95% had at least 1 prior abdominal/pelvic surgery, and 61% had at least 1 prior hernia repair. Postoperative complications included 20.3% of patients requiring drainage of a fluid collection in the clinic setting, and 29.3% of patients requiring return to the operating room for any reason (including superficial wound debridement). The average defect size was 231.88 ± 195.86 cm2, the mean follow-up was 3.11 ± 1.83 years, and the recurrence rate was 5.1%.

CONCLUSIONS

We report a hernia recurrence rate of 5.1% in a high-risk population with complex defects at a mean of 3.1 years of follow-up using onlay mesh fixated with multipoint progressive tension sutures. This recurrence rate is similar to that reported for both underlay and sublay techniques. However, the onlay approach is technically easier, faster, and less invasive compared with underlay and sublay techniques, which may translate into wider reproducibility, lower costs, and improved patient safety.

Biologic Mesh in Surgery: A Comprehensive Review and Meta-Analysis of Selected Outcomes in 51 Studies and 6079 Patients

BACKGROUND

In recent decades, biologic mesh (BM) has become an important adjunct to surgical practice. Recent evidence-based clinical applications of BM include but are not limited to: reconstruction of abdominal wall defects; breast reconstruction; face, head and neck surgery; periodontal surgery; other hernia repairs (diaphragmatic, hiatal/paraesophageal, inguinal and perineal); hand surgery; and shoulder arthroplasty. Prior systematic reviews of BM in complex abdominal wall hernia repair had several shortcomings that our comprehensive review seeks to address, including exclusion of laparoscopic repair, assessment of risk of bias, use of an acceptable meta-analytic method and review of risk factors identified in multivariable regression analyses.

MATERIALS AND METHODS

We sought articles of BM for open ventral hernia repair reporting on early complications, late complications or recurrences and included minimum of 50. We used the quality in prognostic studies risk of bias assessment tool. Random effects meta-analysis was applied.

RESULTS

This comprehensive review selected 62 articles from 51 studies that included 6,079 patients. Meta-analytic pooling found that early complications are present in about 50%, surgical site occurrences (SSOs) in 37%, surgical site infections (SSIs) in 18%, reoperation in 7%, readmission in 20% and mortality in 3%. Meta-analytic estimates of late outcomes included overall complications (42%), SSOs (40%) and SSIs (22%). Specific SSOs included seroma (14%), hematoma (4%), abscess (10%), necrosis (5%), dehiscence (8%) and fistula formation (5%). Reoperation occurred in about 17%, mesh explantation in 9% and recurrence in 36%.

CONCLUSION

Estimates of nearly all outcomes from individual studies were highly heterogeneous and sensitivity analyses and meta-regressions generally failed to explain this heterogeneity. Recurrence is the only outcome for which there are consistent findings for risk factors. Bridge placement of BM is associated with higher risk of recurrence. Prior hernia repair, history of reintervention and history of mesh removal were also risk factors for increased recurrence.

Use of Polypropylene Mesh in the Management of a Contaminated Large Ventral Hernia: A Contraindication or a Solution?

Management of contaminated large ventral hernias is still a challenge as a result of massive loss of muscular and fascial tissues in the abdominal wall, traditional contraindication to use of a prosthesis, and complicated perioperative management. This study aimed to provide a solution for this challenging dilemma using monofilament polypropylene mesh (Marlex; Bard) in the Sublay-Bridge fashion. Twenty-three consecutive patients with contaminated large ventral hernias from 2009 to 2011 were identified. Preoperatively, source of contamination at the surgical site was managed through oral antibiotics, wound débridement, and dressing change; the hernia content was reduced into the abdominal cavity gradually and an abdominal binder was applied. Marlex meshes in the Sublay-Bridge fashion were used in these patients. Demographic and perioperative data were collected. Fourteen males and nine females were included with a mean age of 52.5 ± 10.5 years and a mean body mass index of 25.2 ± 6.1 kg/m2. Twelve patients underwent ostomy takedown, which was the most common indication. Mean hernia size was 120.5 ± 18.5 cm2 and a mean mesh size was 380.0 ± 80.5 cm2. The mean operative time was 125.5 ± 35.5 minutes and the hospital stay was 10.0 ± 3.5 days. Twenty-three patients had a mean follow-up period of 12.5 ± 6.5 months. An iatrogenic bladder injury occurred because of severe prevesical adhesion attributed to previous prosthesis repair. There was no presentation of abdominal compartment syndrome. Four patients developed surgical site infection and managed with conservative therapy without mesh removal. Three patients had seromas and underwent aspiration guided by B-ultrasound. Three patients reported chronic foreign body sensation. No recurrence was followed up. Repair of contaminated large ventral hernia using a Marlex mesh in the Sublay-Bridge fashion is safe and efficient management. Perioperative management and operative technology play important roles in dealing with this problem.

Biological mesh used to repair perineal hernias following abdominoperineal resection for anorectal cancer

PURPOSE

This study aimed to determine the outcome for patients who had undergone perineal hernia repair, via a perineal approach, using a biological mesh post-abdominoperineal excision (APE) for anorectal cancer.

METHOD

All consecutive patients having undergone perineal hernia repair involving an extracellular matrix of porcine small intestinal submucosa at our hospital between 2015 and 2018 were included. Follow-up clinical examinations and computed tomography scans were performed.

RESULTS

Six patients were treated surgically for symptomatic perineal hernia after a median of 31 months from APE. The median follow-up after hernia repair was 11 months (interquartile range [IQR], 6-35 months). Three patients (50%) developed a recurrent perineal hernia after a median interval of 6 months.

CONCLUSION

Perineal hernia repair using a biological mesh resulted in a high recurrence rate in patients who had undergone APE for anorectal cancer.

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.

Erratum: Addendum: Abdominal Wall Reconstruction: An Integrated Approach

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

A novel tool to evaluate bias in literature on use of biologic mesh in abdominal wall hernia repair

PURPOSE

Biologic meshes are being increasingly used for abdominal hernia repair in high-risk patients or patients with a previous history of wound infection, due to their infection-resistant properties. Several studies have been carried out to assess whether biologic mesh is superior to synthetic mesh, as well as to establish guidelines for their use. Unfortunately, most of these studies were not rigorously designed and were vulnerable to different types of bias. The systematic reviews that have been published so far on this topic contain the same biases and limitations of the primary articles that are analyzed. The lack of a literature review on the bias on the use of biological mesh prompted us to conduct the literature search, assessment and plan this article.

METHODS

We performed a literature search in PubMed, Embase and Cochrane databases of systematic reviews on biologic mesh for ventral hernia repair. The literature review was conducted using the Population, Intervention, Comparisons, Outcomes and Design approach. We identified 40 studies that matched the stringent criteria we had set. We then created a 13-point instrument to assess for bias and applied it on the primary studies that we intended to analyze.

RESULTS

Most primary studies are case series or case reports of patients undergoing abdominal hernia repair with biologic mesh, without any comparison group, and the inclusion of cases was only specified to be consecutive in 6 out of 40 cases. In terms of assessing outcomes, in none of the 40 articles were the outcome assessors blinded to the intervention or exposure status of participants.

CONCLUSION

The instrument that we created could allow to assess the risk of bias in different kind of studies. Our assessment of the studies based on the criteria that we had set up in the instrument clearly identified that further research needs to be done due to the lack of unbiased studies regarding the use of biologic meshes for abdominal hernia repair.

"Complex abdominal wall" management: evidence-based guidelines of the Italian Consensus Conference

To date, there is no shared consensus on a definition of a complex abdominal wall in elective surgery and in the emergency, on indications, technical details, complications, and follow-up. The purpose of the conference was to lay the foundations for a homogeneous approach to the complex abdominal wall with the primary intent being to attain the following objectives: (1) to develop evidence-based recommendations to define “complex abdominal wall”; (2) indications in emergency and in elective cases; (3) management of “complex abdominal wall”; (4) techniques for temporary abdominal closure. The decompressive laparostomy should be considered in a case of abdominal compartment syndrome in patients with critical conditions or after the failure of a medical treatment or less invasive methods. In the second one, beyond different mechanism, patients with surgical emergency diseases might reach the same pathophysiological end point of trauma patients where a preventive “open abdomen” might be indicated (a temporary abdominal closure: in the case of a non-infected field, the Wittmann patch and the NPWT had the best outcome followed by meshes; in the case of an infected field, NPWT techniques seem to be the preferred). The second priority is to create optimal both general as local conditions for healing: the right antimicrobial management, feeding—preferably by the enteral route—and managing correctly the open abdomen wall. The use of a mesh appears to be—if and when possible—the gold standard. There is a lot of enthusiasm about biological meshes. But the actual evidence supports their use only in contaminated or potentially contaminated fields but above all, to reduce the higher rate of recurrences, the wall anatomy and function should be restored in the midline, with or without component separation technique. On the other site has not to be neglected that the use of monofilament and macroporous non-absorbable meshes, in extraperitoneal position, in the setting of the complex abdomen with contamination, seems to have a cost effective role too. The idea of this consensus conference was mainly to try to bring order in the so copious, but not always so “evident” literature utilizing and exchanging the expertise of different specialists.

Cross-Linked Cholecyst-Derived Extracellular Matrix for Abdominal Wall Repair

Abdominal wall repair frequently utilizes either nondegradable or biodegradable meshes, which are found to stimulate undesirable biological tissue responses or which possess suboptimal degradation rate. In this study, a biologic mesh prototype made from carbodiimide cross-linked cholecyst-derived extracellular matrix (EDCxCEM) was compared with small intestinal submucosa (Surgisis^®), cross-linked bovine pericardium (Peri-Guard^®), and polypropylene (Prolene^®) meshes in an in vivo rabbit model. The macroscopic appearance and stereological parameters of the meshes were evaluated. Tailoring the degradation of the EDCxCEM mesh prevents untimely degradation, while allowing cellular infiltration and mesh remodeling to take place in a slower but predictable manner. The results suggest that the cross-linked biodegradable cholecyst-derived biologic mesh results in no seroma formation, low adhesion, and moderate stretching of the mesh. In contrast to Surgisis, Peri-Guard, and Prolene meshes, the EDCxCEM mesh showed a statistically significant increase in the volume fraction (V_v) of collagen (from 34% to 52.1%) in the central fibrous tissue region at both day 28 and 56. The statistically high length density (L_v), of blood vessels for the EDCxCEM mesh at 28 days was reflected also by the higher cellular activity (high V_v of fibroblast and moderate V_v of nuclei) indicating remodeling of this region in the vicinity of a slowly degrading EDCxCEM mesh. The lack of mesh area stretching/shrinkage in the EDCxCEM mesh showed that the remodeled tissue was adequate to prevent hernia formation. The stereo-histological assays suggest that the EDCxCEM delayed degradation profile supports host wound healing processes including collagen formation, cellular infiltration, and angiogenesis. The use of cross-linked CEM for abdominal wall repair is promising.

Abdominal wall reconstruction following resection of large abdominal aggressive neoplasms using tensor fascia lata flap with or without mesh reinforcement

PURPOSE

Abdominal wall defects caused by neoplasms with large extended resection defects remain a challenging problem. Autologous flaps, meshes, and component separation techniques are effective in reconstructing these defects. We retrospectively reviewed and assessed the success of reconstruction using tensor fascia lata flap with or without meshes.

METHODS

18 patients with abdominal wall neoplasms were identified during the period from 2007 to 2016. A retrospective review of office charts and hospital records was performed.

RESULTS

A total of 18 patients received corresponding treatment according to the degree of defects, with a mean age of 53.89 ± 14.56 years old, a mean body mass index (BMI) of 22.89 ± 4.09 kg/m², and a mean American Society of Anesthesiologist (ASA) score of 2.18 ± 0.75. Operative details included the mean defect size (303.44 ± 175.67 cm²), the mean mesh size (265.92 ± 227.99 cm²), and the mean operative time (382.33 ± 180.38 min). Postoperative wound complications were identified in 7 (39%) patients, including incisional infection, edema and thrombus. Neoplasm recurrence was observed in 2 (13%) primary neoplasms patients. No hernias were present in any patient.

CONCLUSIONS

Abdominal wall defects caused by neoplasms should be repaired by autologous flaps combined with or without mesh reinforcement. Most type I defects should be primary sutured; type II or III defects should be repaired well by flaps, with or without mesh; if the incision is infected or contaminated, biological mesh or flaps are the best choice.

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.

A Meta-analysis of Outcomes Using Acellular Dermal Matrix in Breast and Abdominal Wall Reconstructions: Event Rates and Risk Factors Predictive of Complications

BACKGROUND

The use of acellular dermal matrix (ADM) has gained acceptance in breast and abdominal wall reconstructions. Despite its extensive use, there is currently a wide variation of reported outcomes in the literature. This study definitively elucidates the outcome rates associated with ADM use in breast and abdominal wall surgeries and identifies risk factors predisposing to the development of complications.

METHODS

A literature search was conducted using the Medline database (PubMed, US National Library of Medicine) and the Cochrane Library. A total of 464 articles were identified, of which 53 were eligible for meta-analysis. The endpoints of interest were the incidences of seroma, cellulitis, infection, wound dehiscence, implant failure, and hernia. The effects of various risk factors such as smoking, radiation, chemotherapy, and diabetes on the development of complications were also evaluated.

RESULTS

A majority of the studies were retrospective (68.6%) with a mean follow-up of 16.8 months (SD ± 10.1 months) in the breast group and 14.2 months (SD ± 7.8 months) in the abdominal wall reconstructive group. The overall risks and complications were as follows: cellulitis, 5.1%; implant failure, 5.9%; seroma formation, 8%; wound dehiscence, 8.1%; wound infection, 16.1%; hernia, 27.6%; and abdominal bulging, 28.1%. Complication rates were further stratified separately for the breast and abdominal cohorts, and the data were reported. This provides additional information on the associated abdominal wall morbidity in patients undergoing autologous breast reconstruction in which mesh reinforcement was considered as closure of the abdominal wall donor site. Radiation resulted in a significant increase in the rates of cellulitis (P = 0.021), and chemotherapy was associated with a higher incidence of seroma (P = 0.014).

CONCLUSION

This study evaluates the overall complication rates associated with ADM use by conducting a meta-analysis of published data. This will offer physicians a single comprehensive source of information during informed consent discussions as well as an awareness of the risk factors predictive of complications.

2017 update of the WSES guidelines for emergency repair of complicated abdominal wall hernias

Emergency repair of complicated abdominal wall hernias may be associated with worsen outcome and a significant rate of postoperative complications. There is no consensus on management of complicated abdominal hernias. The main matter of debate is about the use of mesh in case of intestinal resection and the type of mesh to be used. Wound infection is the most common complication encountered and represents an immense burden especially in the presence of a mesh. The recurrence rate is an important topic that influences the final outcome. A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013 with the aim to define recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel. In 2016, the guidelines have been revised and updated according to the most recent available literature.

First human use of hybrid synthetic/biologic mesh in ventral hernia repair: a multicenter trial

BACKGROUND

Mesh options for reinforcement of ventral/incisional hernia (VIH) repair include synthetic or biologic materials. While each material has known advantages and disadvantages, little is understood about outcomes when these materials are used in combination. This multicenter study reports on the first human use of a novel synthetic/biologic hybrid mesh (Zenapro^® Hybrid Hernia Repair Device) for VIH repair.

METHODS

This prospective, multicenter post-market clinical trial enrolled consecutive adults who underwent elective VIH repair with hybrid mesh placed in the intraperitoneal or retromuscular/preperitoneal position. Patients were classified as Ventral Hernia Working Group (VHWG) grades 1-3 and had clean or clean-contaminated wounds. Outcomes of ventral and incisional hernia were compared using appropriate parametric tests.

RESULTS

In all, 63 patients underwent VIH repair with hybrid mesh. Most were females (54.0%), had a mean age of 54.8 ± 10.9 years and mean body mass index of 34.5 ± 7.8 kg/m², and classified as VHWG grade 2 (87.3%). Most defects were midline (92.1%) with a mean area of 106 ± 155 cm². Cases were commonly classified as clean (92.1%) and were performed laparoscopically (60.3%). Primary fascial closure was achieved in 82.5% with 28.2% requiring component separation. Mesh location was frequently intraperitoneal (69.8%). Overall, 39% of patients available for follow-up at 12 months suffered surgical site events, which were generally more frequent after incisional hernia repair. Of these, seroma (23.7%) was most common, but few (8.5%) required procedural intervention. Other surgical site events that required procedural intervention included hematoma (1.7%), wound dehiscence (1.7%), and surgical site infection (3.4%). Recurrence rate was 6.8% (95% CI 2.2-16.6%) at 12-months postoperatively.

CONCLUSION

Zenapro^® Hybrid Hernia Repair Device is safe and effective in VHWG grade 1-2 patients with clean wounds out to 12 months. Short-term outcomes and recurrence rate are acceptable. This hybrid mesh represents a novel option for reinforcement during VIH repair.

Double-blind randomized controlled trial of collagen mesh for the prevention of abdominal incisional hernia in patients having a vertical rectus abdominis myocutaneus flap during surgery for advanced pelvic malignancy

AIM

The study investigated the effect of collagen mesh-assisted closure at the donor site in preventing the formation of incisional hernia following construction of a vertical rectus abdominis myocutaneus (VRAM) flap as part of pelvic surgery for recurrent colorectal cancer.

METHOD

The study was a double-blinded randomized controlled superiority trial that was designed and performed according to the Consolidated Standards of Reporting Trials (CONSORT) Statement. Eligible patients undergoing surgery that included a VRAM flap for advanced colorectal pelvic malignancy were prospectively randomized to conventional abdominal wound closure or collagen mesh-assisted closure. The primary end-point was incisional herniation at 1 year confirmed by CT. Secondary end-points were CT-verified incisional herniation at 3 and 36 months, clinically recognizable incisional herniation, donor-site and reconstructive-site complications, surgical mortality, postoperative morbidity, postoperative recovery and survival.

RESULTS

In total, 58 (29 conventional closure; 29 mesh-assisted closure) patients were included. At 1 year, incisional herniation on the CT scan was found in 12 (50%) of 24 patients in the conventional closure group, and in 8 (33%) of 24 in the mesh-assisted closure group (P = 0.38). No significant difference between the groups was found in surgical mortality, early or late complications or survival. Donor-site morbidity was comparable between the two groups.

CONCLUSION

No preventative effect of collagen mesh-assisted closure was observed following VRAM flap reconstruction.

The host response to naturally-derived extracellular matrix biomaterials

Biomaterials based on natural materials including decellularized tissues and tissue-derived hydrogels are becoming more widely used for clinical applications. Because of their native composition and structure, these biomaterials induce a distinct form of the foreign body response that differs from that of non-native biomaterials. Differences include direct interactions with cells via preserved moieties as well as the ability to undergo remodeling. Moreover, these biomaterials could elicit adaptive immune responses due to the presence of modified native molecules. Therefore, these biomaterials present unique challenges in terms of understanding the progression of the foreign body response. This review covers this response to natural materials including natural polymers, decellularized tissues, cell-derived matrix, tissue derived hydrogels, and biohybrid materials. With the expansion of the fields of regenerative medicine and tissue engineering, the current repertoire of biomaterials has also expanded and requires continuous investigation of the responses they elicit.

Association Between Delayed Graft Function and Incisional Hernia after Renal Transplant

OBJECTIVES

Incisional hernias can occur after any abdominal operation, including after renal transplant. Several risk factors have been identified in nonimmunosuppressed surgical patients. We aimed to identify whether specific risk factors correlated with the development of incisional hernias after renal transplant. The existence of associations between these risk factors and postoperative complications was also reviewed.

MATERIALS AND METHODS

We reviewed 969 kidney transplants performed between February 2000 and January 2011. Thirty-nine kidney transplant recipients who were treated with rapamycin were excluded. The following potential risk factors were evaluated: recipient age, sex, body mass index at transplant, delayed graft function, diabetes, albumin, postoperative platelet count, drain placement, donor body mass index, donor type, warm ischemic time, and cold ischemic time. We performed univariate and multivariate logistic regression tests.

RESULTS

In our patient group, a total of 52 (5.4%) transplants were complicated by incisional hernia. On univariate analysis, we found that delayed graft function (P = .001) and infection (P < .001) were statistically significant predictors for development of incisional hernia. Multivariate analyses revealed that delayed graft function and length of stay remained statistically significant predictors.

CONCLUSIONS

Delayed graft function and length of stay are significant predictors of incisional hernia after kidney transplant.

Use of small intestinal submucosal and acellular dermal matrix grafts in giant omphaloceles in neonates and a rabbit abdominal wall defect model

BACKGROUND

The described surgical strategies for the management of omphalocele include primary closure, staged closure, and delayed closure. A primary repair is not suitable for all giant omphaloceles. We implanted two grafts, small intestinal submucosal (SIS) and acellular dermal matrix (ADM) onto abdominal wall defects in neonates to study the safety and efficacy of SIS and ADM graft techniques for initial closure of giant omphaloceles in infants, and we also implanted these grafts onto abdominal wall defects in an animal model.

METHODS

Twenty-four patients with giant omphaloceles were divided into two groups (ADM group, 12 patients; SIS group, 12 patients). The operative time, skin healing time postoperatively, and the incidence of skin infections, and abdominal wall hernias were observed. In the rabbit animal model, bilateral full-thickness incisions were made through the rabbit rectus abdominus muscles and a 2×4cm longitudinal whole layer defect was created on either the left or right lateral anterior abdominal wall. A four-layered variant of the SIS graft was used to repair the right abdominal defect; ADM was used to repair the left. Tensile strength was measured using an Instron tensiometer. Electron scanning and light microscopy were used to evaluate neovascularization, collagen deposition, and muscle fibers at 2, 4, 8, and 16weeks postimplantation.

RESULTS

In the neonatal patients, there was no statistically significant difference between the two groups with respect to operative time, skin healing time postoperatively, the incidence of skin infections, or abdominal wall hernias. In the SIS group, only one patient developed a skin infection, which led to skin necrosis and sloughing. In the ADM group, four patients developed skin infection postoperatively, and the patch was gradually removed. In the animal study, there was no significant difference between the mean breaking strength of ADM versus SIS repairs. Scanning electron and light microscopy showed collagen deposition, increased vascularization, fibroblasts, and muscular regeneration in both SIS and ADM repairs. SEM showed that the SIS graft was absorbed, while ADM was not. Light microscopy showed foreign body macrophages in ADM, but not in the SIS repairs.

CONCLUSION

SIS and ADM grafts adequately enhance healing with a low complication rate. Compared with ADM grafts, SIS is absorbable, induces less inflammation, and is more biocompatible, and therefore might be more useful and suitable for closure of abdominal wall defects.

Perfusion-decellularized skeletal muscle as a three-dimensional scaffold with a vascular network template

There exists a great need for repair grafts with similar volume to human skeletal muscle that can promote the innate ability of muscle to regenerate following volumetric muscle loss. Perfusion decellularization is an attractive technique for extracellular matrix (ECM) scaffold from intact mammalian organ or tissue which has been successfully used in tissue reconstruction. The perfusion-decellularization of skeletal muscle has been poorly assessed and characterized, but the bioactivity and functional capacity of the obtained perfusion skeletal muscle ECM (pM-ECM) to remodel in vivo is unknown. In the present study, pM-ECM was prepared from porcine rectus abdominis (RA). Perfusion-decellularization of porcine RA effectively removed cellular and nuclear material while retaining the intricate three-dimensional microarchitecture and vasculature networks of the native RA, and many of the bioactive ECM components and mechanical properties. In vivo, partial-thickness abdominal wall defects in rats repaired with pM-ECM showed improved neovascularization, myogenesis and functional recellularization compared to porcine-derived small intestinal submucosa (SIS). These findings show the biologic potential of RA pM-ECM as a scaffold for supporting site appropriate, tissue reconstruction, and provide a better understanding of the importance maintaining the tissue-specific complex three-dimensional architecture of ECM during decellularization and regeneration.

Inhibition of COX1/2 alters the host response and reduces ECM scaffold mediated constructive tissue remodeling in a rodent model of skeletal muscle injury

Extracellular matrix (ECM) has been used as a biologic scaffold material to both reinforce the surgical repair of soft tissue and serve as an inductive template to promote a constructive tissue remodeling response. Success of such an approach is dependent on macrophage-mediated degradation and remodeling of the biologic scaffold. Macrophage phenotype during these processes is a predictive factor of the eventual remodeling outcome. ECM scaffolds have been shown to promote an anti-inflammatory or M2-like macrophage phenotype in vitro that includes secretion of downstream products of cycolooxygenases 1 and 2 (COX1/2). The present study investigated the effect of a common COX1/2 inhibitor (Aspirin) on macrophage phenotype and tissue remodeling in a rodent model of ECM scaffold treated skeletal muscle injury. Inhibition of COX1/2 reduced the constructive remodeling response by hindering myogenesis and collagen deposition in the defect area. The inhibited response was correlated with a reduction in M2-like macrophages in the defect area. The effects of Aspirin on macrophage phenotype were corroborated using an established in vitro macrophage model which showed a reduction in both ECM induced prostaglandin secretion and expression of a marker of M2-like macrophages (CD206). These results raise questions regarding the common peri-surgical administration of COX1/2 inhibitors when biologic scaffold materials are used to facilitate muscle repair/regeneration.

STATEMENT OF SIGNIFICANCE

COX1/2 inhibitors such as nonsteroidal anti-inflammatory drugs (NSAIDs) are routinely administered post-surgically for analgesic purposes. While COX1/2 inhibitors are important in pain management, they have also been shown to delay or diminish the healing process, which calls to question their clinical use for treating musculotendinous injuries. The present study aimed to investigate the influence of a common NSAID, Aspirin, on the constructive remodeling response mediated by an ECM scaffold (UBM) in a rat skeletal muscle injury model. The COX1/2 inhibitor, Aspirin, was found to mitigate the ECM scaffold-mediated constructive remodeling response both in an in vitro co-culture system and an in vivo rat model of skeletal muscle injury. The results presented herein provide data showing that NSAIDs may significantly alter tissue remodeling outcomes when a biomaterial is used in a regenerative medicine/tissue engineering application. Thus, the decision to prescribe NSAIDs to manage the symptoms of inflammation post-ECM scaffold implantation should be carefully considered.

Biologic mesh versus synthetic mesh in open inguinal hernia repair: system review and meta-analysis

BACKGROUND

Biologic meshes are mostly used for abdominal wall reinforcement in infected fields, but no consensus has been reached on its use for inguinal hernia repairing. The purpose of this study was to compare biologic mesh with synthetic mesh in open inguinal herniorrhaphy.

METHODS

A systematic literature review and meta-analysis was undertaken to identify studies comparing the outcomes of biologic mesh and synthetic mesh in open inguinal hernia repair. Published studies were identified by the databases PubMed, EMBASE and the Cochrane Library.

RESULTS

A total of 382 patients in five randomized controlled trials were reviewed (179 patients in biologic mesh group; 203 patients in synthetic mesh group). The two groups did not significantly differ in chronic groin pain (P = 0.06) or recurrence (P = 0.38). The incidence of seroma trended higher in biologic mesh group (P = 0.03). Operating time was significantly longer with biologic mesh (P = 0.03). There was no significant difference in hematomas (P = 0.23) between the two groups.

CONCLUSIONS

From the data of this study, biologic mesh had no superiority to synthetic mesh in open inguinal hernia repair with similar recurrence rates and incidence of chronic groin pain, but higher rate of seroma and longer operating time. However, this mesh still needs to be assessed in a large, multicentre, well-designed randomized controlled trial.

Diaphragm Repair with a Novel Cross-Linked Collagen Biomaterial in a Growing Rabbit Model

Background

Neonates with congenital diaphragmatic hernia and large defects often require patch closure. Acellular collagen matrices (ACM) have been suggested as an alternative to synthetic durable patches as they are remodeled by the host or could also be used for tissue engineering purposes.

Materials and Methods

2.0x1.0 cm diaphragmatic defects were created in 6-weeks old New-Zealand white rabbits. We compared reconstruction with a purpose-designed cross-linked ACM (Matricel) to 4-layer non-cross-linked small intestinal submucosa (SIS) and a 1-layer synthetic Dual Mesh (Gore-Tex). Unoperated animals or animals undergoing primary closure (4/0 polyglecaprone) served as age-matched controls. 60 (n = 25) resp. 90 (n = 17) days later, animals underwent chest x-ray and obduction for gross examination of explants, scoring of adhesion and inflammatory response. Also, uniaxial tensiometry was done, comparing explants to contralateral native diaphragmatic tissue.

Results

Overall weight nearly doubled from 1,554±242 g at surgery to 2,837±265 g at obduction (+84%). X-rays did show rare elevation of the left diaphragm (SIS = 1, Gore-Tex = 1, unoperated control = 1), but no herniation of abdominal organs. 56% of SIS and 10% of Matricel patches degraded with visceral bulging in four (SIS = 3, Matricel = 1). Adhesion scores were limited: 0.5 (Matricel) to 1 (SIS, Gore-Tex) to the left lung (p = 0.008) and 2.5 (Gore-Tex), 3 (SIS) and 4 (Matricel) to the liver (p<0.0001). Tensiometry revealed a reduced bursting strength but normal compliance for SIS. Compliance was reduced in Matricel and Gore-Tex (p<0.01). Inflammatory response was characterized by a more polymorphonuclear cell (SIS) resp. macrophage (Matricel) type of infiltrate (p<0.05). Fibrosis was similar for all groups, except there was less mature collagen deposited to Gore-Tex implants (p<0.05).

Conclusions

Matricel induced a macrophage-dominated inflammatory response, more adhesions, had appropriate strength but a lesser compliance compared to native tissue. The herein investigated ACM is not a viable option for CDH repair.

Use of Acellular Dermal Matrix Combined with a Component Separation Technique for Repair of Contaminated Large Ventral Hernias: A Possible Ideal Solution for this Clinical Challenge

Repair of large contaminated ventral hernias is always challenging because of massive loss of muscular and fascial tissues, high risk of surgical infection and recurrence, and contraindication to use of a permanent prosthesis. This study reviewed retrospectively data of 35 patients with contaminated large ventral hernias who received repair using acellular dermal matrix combined with a component separation technique from 2009 to 2011. Twenty-one males and 14 females were identified with a mean age of 45.5 ± 12.5 years and a mean body mass index of 22.5 ± 5.8 kg/m2. Simultaneously, nine patients underwent bowel fistula resection, 13 patients underwent ostomy takedown, five patients underwent recurrent colon cancer dissection, and eight patients underwent infectious permanent mesh removal and wound débridement. Mean defect size was 125.0 ± 23.5 cm2. The aponeurosis of the external oblique muscle was transected and separated from internal oblique muscle to reach abdominal closure. A cellular dermal matrix was placed in an onlay fashion and mean mesh size was 300.0 ± 65.0 cm2. Thirty-five patients had a mean follow-up period of 36.5 ± 12.5 months. Wound bleeding and partial dehiscence occurred at 36 hours post-operatively. Five patients reported abdominal wall pain during the first postoperative month. Five patients developed surgical site infection. Four patients were detected to develop seroma with volume more than 20 mL by B-ultrasound examination. No recurrence and chronic foreign body sensation were followed up. Use of acellular dermal matrix combined with a component separation technique is safe and efficient management for repair of contaminated large ventral hernia, in which permanent prosthesis placement is contraindicated.

Concomitant laparoscopic intraperitoneal onlay mesh repair with other clean contaminated procedures-study of feasibility and safety

BACKGROUND

Laparoscopic ventral hernia mesh repair has gained wide popularity with the benefits of shorter hospital stay, improved patient outcome, and fewer complications compared with traditional open procedures. It also offers the advantage of combining procedures at different quadrants of the abdomen. In this article we have retrospectively studied the safety of combining laparoscopic intraperitoneal onlay mesh (IPOM) repair with clean contaminated surgeries like cholecystectomy and hysterectomy.

MATERIALS AND METHODS

The data of all patients who received concomitant laparoscopic ventral hernia repairs along with cholecystectomy and hysterectomy were collected retrospectively. The details of these surgeries and the immediate postoperative outcome parameters were analyzed.

RESULTS

Between January 2006 and January 2011, 246 cases of laparoscopic IPOM in combination with clean contaminated surgeries were performed. Of these, 126 were hysterectomies, and 120 were cholecystectomies. Mean operating time for laparoscopic IPOM with cholecystectomy was 136 minutes (range, 112-172 minutes), and that for laparoscopic IPOM with hysterectomy was 224 minutes (range, 196-285 minutes). The average hospital stays were 4.3 days (range, 3-7 days) for laparoscopic IPOM with hysterectomy and 2.73 days (range, 1-5 days) for laparoscopic IPOM with cholecystectomy. Thirty-six patients (14.6%) developed seroma, for which 16 patients (6.5%) warranted aspiration. We had 0.8% mesh infection in total. The recurrence rates were 0.83% (n=1) in the cholecystectomy group and 0.8% (n=1) in the hysterectomy group.

CONCLUSIONS

Laparoscopic IPOM can be performed simultaneously with selected clean contaminated surgeries with acceptable morbidity. Combining clean contaminated surgeries does not significantly alter the outcome of the procedure.

A primer on wound healing in colorectal surgery in the age of bioprosthetic materials

Wound healing is a complex, dynamic process that is vital for closure of cutaneous injuries, restoration of abdominal wall integrity after laparotomy closure, and to prevent anastomotic dehiscence after bowel surgery. Derangements in healing have been described in multiple processes including diabetes mellitus, corticosteroid use, irradiation for malignancy, and inflammatory bowel disease. A thorough understanding of the process of healing is necessary for clinical decision making and knowledge of the current state of the science may lead future researchers in developing methods to enable our ability to modulate healing, ultimately improving outcomes. An exciting example of this ability is the use of bioprosthetic materials used for abdominal wall surgery (hernia repair/reconstruction). These bioprosthetic meshes are able to regenerate and remodel from an allograft or xenograft collagen matrix into site-specific tissue; ultimately being degraded and minimizing the risk of long-term complications seen with synthetic materials. The purpose of this article is to review healing as it relates to cutaneous and intestinal trauma and surgery, factors that impact wound healing, and wound healing as it pertains to bioprosthetic materials.

Onlay ventral hernia repairs using porcine non-cross-linked dermal biologic mesh

INTRODUCTION

Ventral hernias are common and repair with mesh has been shown to reduce recurrence. However, synthetic mesh is associated with a risk of infection. Biologic mesh is an alternative that may be less susceptible to infection. Typically, the sublay position is preferred for mesh placement but this technique takes longer and has not been shown to have a lower recurrence rate than an onlay mesh. The aim of this study was to evaluate the outcome of complex ventral hernia repair using a porcine non-cross-linked biologic mesh onlay.

METHODS

A retrospective chart review was performed of all patients that had a ventral hernia repair with biologic mesh from January 2009 to March 2012. The operative procedure in all patients was an open repair with primary fascial closure (if possible) with or without external oblique component separation and porcine biologic mesh onlay.

RESULTS

There were 22 patients that had a ventral hernia repair, 19 primary and 3 recurrent. The majority were men, had hernia grade 3 or 4, and developed the hernia after an esophagectomy or gastrectomy for cancer. All but one had primary closure with a porcine biologic mesh onlay. One patient was bridged for loss of domain. A bilateral external oblique component separation was added in 16 patients (73 %). The median hospital stay was 7 days. There were two superficial wound infections, one with exposed mesh, but no patient required mesh removal. A seroma requiring intervention developed in 6 patients (27 %) and resolved with pig-tail drainage. At a median follow-up of 7 months, there has been no hernia recurrence apart from the patient that was bridged.

CONCLUSIONS

Porcine non-cross-linked biologic mesh overlay has excellent short-term results in patients at increased risk for mesh infection. No patient required mesh removal, and there have been no recurrent hernias in patients with primary fascial closure. Biologic bridging is not effective for long-term abdominal wall reconstruction.

Effects of macroporous monofilament mesh on infection in a contaminated field

BACKGROUND

The aim of this study was to evaluate whether the type of the mesh and proper surgical technique can influence the outcome of a tension-free hernia repair in a contaminated filed.

MATERIALS AND METHODS

This study was based on the model of bacterial peritonitis in rats induced with a mixture composed of Escherichia coli and Bacteroides fragilis. Two animals were used as a control group without induced peritonitis and 10 animals with mesh implanted inside of the peritoneal cavity. For the 20 animals in the studied group, bacterial fluid was applied into the abdominal cavity together with the mesh implantation. In 10 cases, the mesh was fixed flatly upon the surface of the peritoneum; in the other 10, the mesh was rolled and then fixed within the peritoneal cavity. After 5 weeks, the animals were operated on again, and the meshes, the peritoneal fluid and, if present, any granulomas were taken for bacterial cultivation.

RESULTS

The results of the bacterial cultivation of the material from the control group (without mesh) and from the rats with flatly fixed mesh were almost completely negative (0/10 and 1/10, respectively). In 9 out of 10 rats that were exposed to the rolled mesh for 5 weeks, the colonisation of meshes with both B. fragilis and E. coli was found (p < 0.0198).

CONCLUSIONS

When properly fixed, flat mesh, even in a contaminated field, may allow for a proper mesh healing and does not influence the ability to cure bacterial peritonitis in an animal model. A bad surgical technique, such as inadequately positioned or rolled mesh, may cause persistent peritoneal bacteraemia.

Biologic versus nonbiologic mesh in ventral hernia repair: a systematic review and meta-analysis

BACKGROUND

The current standard of treatment for most ventral hernias is a mesh-based repair. Little is known about the safety and efficacy of biologic versus nonbiologic grafts. A meta-analysis was performed to examine two primary outcomes: recurrence and wound complication rates.

METHODS

Electronic databases and reference lists of relevant articles were systematically searched for all clinical trials and cohort studies published between January 1990 and January 2012. A total of eight retrospective studies, with 1,229 patients, were included in the final analysis.

RESULTS

Biologic grafts had significantly fewer infectious wound complications (p < 0.00001). However, the recurrence rates of biologic and nonbiologic mesh were not different. In subgroup analysis, there was no difference in recurrence rates and wound complications between human-derived and porcine-derived biologic grafts.

CONCLUSIONS

Use of biologic mesh for ventral hernia repair results in less infectious wound complications but similar recurrence rates compared to nonbiologic mesh. This supports the application of biologic mesh for ventral hernia repair in high-risk patients or patients with a previous history of wound infection only when the significant additional cost of these materials can be justified and synthetic mesh is considered inappropriate.

Does mesh location matter in abdominal wall reconstruction? A systematic review of the literature and a summary of recommendations

BACKGROUND

Mesh implantation during abdominal wall reconstruction decreases rates of ventral hernia recurrence and has become the dominant method of repair. The authors provide a comprehensive comparison of surgical outcomes and complications by location of mesh placement following ventral hernia repair with onlay, interposition, retrorectus, or underlay mesh.

METHODS

A systematic search of the English literature published from 1996 to 2012 in the PubMed, MEDLINE, and Cochrane library databases was conducted to identify patients who underwent abdominal wall reconstruction using either prosthetic or biological mesh for ventral hernia repair. Demographic information was obtained from each study.

RESULTS

Sixty-two relevant articles were included with 5824 patients treated with mesh repair of a ventral hernia between 1996 and 2012. Mesh position included onlay (19.6 percent), underlay (60.7 percent), interposition (6.4 percent), and retrorectus (12.4 percent). Prosthetic mesh was used in 80 percent of repairs and biological mesh in 20 percent. The weighted mean incidences of early events were as follows: wound complications, 19 percent; wound infections, 8 percent; seroma or hematoma formation, 11 percent; and reoperation, 10 percent. The weighted mean incidences of late complications included 8 percent for hernia recurrence and 2 percent for mesh explantation. Recurrence rates were highest for onlay (17 percent) or interposition (17 percent) reinforcement. The infection rate was also highest in the interposition cohort (25 percent). Seroma rates were lowest following a retrorectus repair (4 percent).

CONCLUSIONS

Mesh reinforcement of a ventral hernia repair is safe and efficacious, but the location of the reinforcement appears to influence outcomes. Underlay or retrorectus mesh placement is associated with lower recurrence rates.

Is the use of prosthetic mesh recommended in severely obese patients undergoing concomitant abdominal wall hernia repair and sleeve gastrectomy?

BACKGROUND

The concomitant use of nonabsorbable mesh during stapled bariatric surgery has been discouraged due to potential contamination. The aim of our study was to compare and quantify the extent of bacterial load and gross contamination of the peritoneal cavity in patients undergoing laparoscopic sleeve gastrectomy (LSG) vs those undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB).

STUDY DESIGN

We prospectively enrolled all patients undergoing LSG and LRYGB. Peritoneal fluid aspirate samples were collected from each subject. Sample A was obtained at the beginning of the procedure, and sample B was obtained at the end of the procedure either from the staple line wash of the LSG or the gastrojejunostomy in the LRYGB.

RESULTS

A total of 77 patients (51 LSG and 26 LRYGB) and 154 samples (102 from LSG and 52 from LRYGB) were included in this study. All samples obtained at the beginning of each procedure (sample A) were culture negative. Samples of peritoneal fluid obtained at the end of the procedure (sample B) in sleeve gastrectomy procedures were all negative (0%) after a minimum of 72 hours for aerobic and anaerobic cultures. Those obtained for LRYGB (sample B) were culture positive in 4 of 26 (15%). The latter results are statistically significant (p < 0.05).

CONCLUSIONS

Intraperitoneal bacterial cultures in patients undergoing LSG are negative, contrary to those in patients undergoing LRYGB. The concomitant use of prosthetic material to repair ventral hernias in patients undergoing an LSG procedure should be safe and feasible.

WSES guidelines for emergency repair of complicated abdominal wall hernias

Emergency repair of complicated abdominal hernias is associated with poor prognosis and a high rate of post-operative complications.A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013, during the 2nd Congress of the World Society of Emergency Surgery with the goal of defining recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel.

Differentiation of human bone marrow mesenchymal stem cells on decellularized extracellular matrix materials

Mesenchymal bone marrow stromal cells may be a source of cells to preseed decellularized biologic mesh materials for improved cellularization and promote a more physiologic tissue after remodeling. Spontaneous differentiation of mesenchymal stromal cells on the decellularized material would be undesirable. Conversely, induced differentiation of mesenchymal stem cells (MSC) on the material would suggest that these materials may have promise as scaffold materials for bone, cartilage, or adipocyte formation. Two sources of mesenchymal cells were evaluated for induced differentiation in control wells. These MSCs were also evaluated for spontaneous or induced differentiation on decellularized porcine dermis and mesothelium materials. Primarily harvested bone marrow MSCs and commercially obtained MSCs were induced into osteoblasts and adipocytes on decellularized dermis and mesothelium materials. The MSCs were able to be induced into chondrocytes in pellet form but not when grown as a monolayer on the materials. The MSCs did not undergo spontaneous differentiation when grown on the materials for up to four weeks. MSC grown on decellularized porcine dermis or mesothelium do not spontaneously differentiate and may serve as a source of autologous cells for preseeding these extracellular matrix materials prior to implantation.