Hernia repair with porcine small-intestinal submucosa

Non-mesh inguinal hernia repair: Review

Hernioplasty stands as one of the most common abdominal surgical interventions. The "gold standard" treatment for inguinal hernias remains Lichtenstein mesh hernioplasty. Nonetheless, clinical practice continues to grapple with issues concerning complications such as recurrence, chronic postoperative pain, and infection. The myriad types of surgery lead to conflicting opinions regarding the superiority and drawbacks of inguinal canal plastic surgery methods. This article presents current data on the surgical treatment of non-mesh inguinal hernias, delineating the most prevalent techniques while exploring their respective advantages and disadvantages. Additionally, the researchers' experiences are analyzed in detail.

Abdominal wall hernia repair: from prosthetic meshes to smart materials

Hernia reconstruction is one of the most frequently practiced surgical procedures worldwide. Plastic surgery plays a pivotal role in reestablishing desired abdominal wall structure and function without the drawbacks traditionally associated with general surgery as excessive tension, postoperative pain, poor repair outcomes, and frequent recurrence. Surgical meshes have been the preferential choice for abdominal wall hernia repair to achieve the physical integrity and equivalent components of musculofascial layers. Despite the relevant progress in recent years, there are still unsolved challenges in surgical mesh design and complication settlement. This review provides a systemic summary of the hernia surgical mesh development deeply related to abdominal wall hernia pathology and classification. Commercial meshes, the first-generation prosthetic materials, and the most commonly used repair materials in the clinic are described in detail, addressing constrain side effects and rational strategies to establish characteristics of ideal hernia repair meshes. The engineered prosthetics are defined as a transit to the biomimetic smart hernia repair scaffolds with specific advantages and disadvantages, including hydrogel scaffolds, electrospinning membranes, and three-dimensional patches. Lastly, this review critically outlines the future research direction for successful hernia repair solutions by combing state-of-the-art techniques and materials.

Advancements and Utilizations of Scaffolds in Tissue Engineering and Drug Delivery

The drug development process requires a thorough understanding of the scaffold and its three-dimensional structure. Scaffolding is a technique for tissue engineering and the formation of contemporary functioning tissues. Tissue engineering is sometimes referred to as regenerative medicine. They also ensure that drugs are delivered with precision. Information regarding scaffolding techniques, scaffolding kinds, and other relevant facts, such as 3D nanostructuring, are discussed in depth in this literature. They are specific and demonstrate localized action for a specific reason. Scaffold's acquisition nature and flexibility make it a new drug delivery technology with good availability and structural parameter management.

Lichtenstein inguinal hernia repairs with porcine small intestine submucosa: a 5- year follow-up. a prospective randomized controlled study

Porcine small intestine submucosa (SIS) biologic patch has been used in inguinal hernia repair. However, there are little data available to assess the long-term effect after repair. This study aimed to explore the long-term effect of SIS patch in open inguinal hernia repair. Sevent-six patients with unilateral inguinal hernia were treated with Lichtenstein tension-free hernia repair using SIS patch (Beijing Datsing Bio-Tech Co., Ltd.) and Surgisis patch (COOK, USA) in Tianjin Union Medical Center and China-Japan Friendship Hospital. In the trial, the long-term efficacy of the treatment group and the control group were compared. A total of 66 patients in both groups received long-term follow-up (> 5 years) after surgery, with a follow-up rate of 86.8%. During the follow-up period, there was one case of recurrence, one case of chronic pain in the control group. There was no statistically significant difference (P > 0.05) in terms of recurrence, chronic pain, foreign body sensation and infection between the two groups of patients. After long-term observations, it has been found that the porcine small intestinal submucosa (SIS) biological patch is safe and effective for inguinal hernia Lichtenstein repair, and has a low recurrence rate and complication rate.

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.

Extracellular matrix-based biomaterial scaffolds and the host response

Extracellular matrix (ECM) collectively represents a class of naturally derived proteinaceous biomaterials purified from harvested organs and tissues with increasing scientific focus and utility in tissue engineering and repair. This interest stems predominantly from the largely unproven concept that processed ECM biomaterials as natural tissue-derived matrices better integrate with host tissue than purely synthetic biomaterials. Nearly every tissue type has been decellularized and processed for re-use as tissue-derived ECM protein implants and scaffolds. To date, however, little consensus exists for defining ECM compositions or sources that best constitute decellularized biomaterials that might better heal, integrate with host tissues and avoid the foreign body response (FBR). Metrics used to assess ECM performance in biomaterial implants are arbitrary and contextually specific by convention. Few comparisons for in vivo host responses to ECM implants from different sources are published. This review discusses current ECM-derived biomaterials characterization methods including relationships between ECM material compositions from different sources, properties and host tissue response as implants. Relevant preclinical in vivo models are compared along with their associated advantages and limitations, and the current state of various metrics used to define material integration and biocompatibility are discussed. Commonly applied applications of these ECM-derived biomaterials as stand-alone implanted matrices and devices are compared with respect to host tissue responses.

Porcine acellular lung matrix for wound healing and abdominal wall reconstruction: A pilot study

Surgical wound healing applications require bioprosthetics that promote cellular infiltration and vessel formation, metrics associated with increased mechanical strength and resistance to infection. Porcine acellular lung matrix is a novel tissue scaffold known to promote cell adherence while minimizing inflammatory reactions. In this study, we evaluate the capacity of porcine acellular lung matrix to sustain cellularization and neovascularization in a rat model of subcutaneous implantation and chronic hernia repair. We hypothesize that, compared to human acellular dermal matrix, porcine acellular lung matrix would promote greater cell infiltration and vessel formation. Following pneumonectomy, porcine lungs were processed and characterized histologically and by scanning electron microscopy to demonstrate efficacy of the decellularization. Using a rat model of subcutaneou implantation, porcine acellular lung matrices (n = 8) and human acellular dermal matrices (n = 8) were incubated in vivo for 6 weeks. To evaluate performance under mechanically stressed conditions, porcine acellular lung matrices (n = 7) and human acellular dermal matrices (n = 7) were implanted in a rat model of chronic ventral incisional hernia repair for 6 weeks. After 6 weeks, tissues were evaluated using hematoxylin and eosin and Masson’s trichrome staining to quantify cell infiltration and vessel formation. Porcine acellular lung matrices were shown to be successfully decellularized. Following subcutaneous implantation, macroscopic vessel formation was evident. Porcine acellular lung matrices demonstrated sufficient incorporation and showed no evidence of mechanical failure after ventral hernia repair. Porcine acellular lung matrices demonstrated significantly greater cellular density and vessel formation when compared to human acellular dermal matrix. Vessel sizes were similar across all groups. Cell infiltration and vessel formation are well-characterized metrics of incorporation associated with improved surgical outcomes. Porcine acellular lung matrices are a novel class of acellular tissue scaffold. The increased cell and vessel density may promote long-term improved incorporation and mechanical properties. These findings may be due to the native lung scaffold architecture guiding cell migration and vessel formation. Porcine acellular lung matrices represent a new alternative for surgical wound healing applications where increased cell density and vessel formation are sought.

Comparison of Porcine Small Intestinal Submucosa versus Polypropylene in Open Inguinal Hernia Repair: A Systematic Review and Meta-Analysis

Background

A systematic review and meta-analysis was performed in randomized controlled trials (RCTs) to compare porcine small intestinal submucosa (SIS) with polypropylene in open inguinal hernia repair.

Method

Electronic databases MEDLINE, Embase, and the Cochrane Library were used to compare patient outcomes for the two groups via meta-analysis.

Result

A total of 3 randomized controlled trials encompassing 200 patients were included in the meta-analysis. There was no significant difference in recurrence (P = 0.16), hematomas (P = 0.06), postoperative pain within 30 days (P = 0.45), or postoperative pain after 1 year (P = 0.12) between the 2 groups. The incidence of discomfort was significantly lower (P = 0.0006) in the SIS group. However, the SIS group experienced a significantly higher incidence of seroma (P = 0.03).

Conclusions

Compared to polypropylene, using SIS in open inguinal hernia repair is associated with a lower incidence of discomfort and a higher incidence of seroma. However, well-designed larger RCT studies with a longer follow-up period are needed to confirm these findings.

Tissue-engineered autologous vaginal organs in patients: a pilot cohort study

BACKGROUND

Several disorders might require vaginal reconstruction, such as congenital abnormalities, injury, or cancer. Reconstructive techniques for which non-vaginal tissue is used can be associated with complications. We assessed the use of engineered vaginal organs in four patients with vaginal aplasia caused by Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS).

METHODS

We invited to participate four consecutive patients who presented over a 3-year period with congenital vaginal aplasia due to MRKHS. Patients were aged 13-18 years. We obtained a vulvar biopsy of autologous tissue from every patient. We cultured, expanded, and seeded epithelial and muscle cells onto biodegradable scaffolds. The organs were constructed and allowed to mature in an incubator in a facility approved for human-tissue manufacturing. We used a perineal approach to surgically implant these organs. We recorded history, physical examination, vaginoscopy, serial tissue biopsies, MRIs, and self-administered Female Sexual Function Index questionnaire results for all patients, with a follow-up of up to 8 years.

FINDINGS

We noted no long-term postoperative surgical complications. Yearly serial biopsies showed a tri-layered structure, consisting of an epithelial cell-lined lumen surrounded by matrix and muscle, with expected components of vaginal tissue present. Immunohistochemical analysis confirmed the presence of phenotypically normal smooth muscle and epithelia. The MRIs, which showed the extent of the vaginal aplasia before surgery, showed the engineered organs and the absence of abnormalities after surgery, which was confirmed with yearly vaginoscopy. A validated self-administered Female Sexual Function Index questionnaire showed variables in the normal range in all areas tested, such as desire, arousal, lubrication, orgasm, satisfaction, and painless intercourse.

INTERPRETATION

Vaginal organs, engineered from the patient's own cells and implanted, showed normal structural and functional variables with a follow-up of up to 8 years. These technologies could be useful in patients requiring vaginal reconstruction.

FUNDING

Wake Forest University and Hospital Infantil de México Federico Gómez.

Bladder augmentation with small intestinal submucosa leads to unsatisfactory long-term results

PURPOSE

To evaluate the use of small intestinal submucosa (SIS) for bladder augmentation in a series of select patients.

MATERIAL AND METHODS

Six patients (age 6.5-15.4, mean 9.8 years) underwent bladder augmentation with SIS: one after a cloacal exstrophy repair, one after multiple surgery of the bladder because of vesicoureteral reflux, two with spina bifida, two after bladder exstrophy repair. All suffered from a microbladder with a mean volume of 61.5 ml (range 15-120, 7-36% of expected bladder capacity for age). Preoperative bladder compliance ranged from 1.0 to 3.3 (mean 1.3) ml/cmH2O.

RESULTS

Follow-up time ranged from 4.6 to 33.5 (mean 24.4) months. An increase of bladder volume was achieved in four patients (53-370 ml, 16-95% of expected bladder capacity for age). Bladder compliance postoperatively ranged from 0.9 to 5.6 (mean 3.0) ml/cmH2O. Histological examinations showed a complete conversion of SIS, leaving irregular urothelial lining and bladder wall containing muscular, vascular and relatively thick connective tissue in four patients and regular urothelium in two patients. Major complications were bladder stones in two patients and a bladder rupture in one patient.

CONCLUSION

Bladder augmentation with SIS in humans failed to fulfill the hopes raised by animal studies. Due to the insufficient increase in bladder compliance and therefore failure to accomplish sufficient protection of the upper urinary tract, bladder augmentation with SIS cannot be recommended as a substitute for enterocystoplasty.

The Italian Register of Biological Prostheses

BACKGROUND

A wide variety of meshes are available for surgical treatment of abdominal wall defects. These meshes are constructed with different materials with different biological properties.

METHODS

A prospective database was instituted (January 2009-December 2010) to register biological prostheses (BPs) implanted in Italy.

RESULTS

A total of 193 cases were registered. The mean age of the patients was 53.1 years (SD ±7.4). The ratio of males to females was 1.3 to 1. The mean body mass index was 28.2 (SD ±4.1). The breakdown of American Society of Anesthesiologists (ASA) scores was as follows: ASA I, 35.7%; ASA II, 27.5%; ASA III, 31.6%, and ASA IV, 5.2%. For ventral-incisional hernias, the mean duration of surgery was 101.1 min (SD ±25.3), while for inguinal-femoral hernias it was 49.2 min (SD ±19.1). The rate of urgent procedures was 36.7%. The surgical field was clean in 57.4% of cases, clean-contaminated in 21.3%, contaminated in 12.3% and dirty in 9%. Techniques used for inguinal-femoral hernias were as follows: Lichtenstein in 66.7%, plug and mesh in 3.8%, transabdominal-preperitoneal in 25.7% and intraperitoneal onlay mesh in 3.8%. The following prostheses were used: swine intestinal submucosa in 54.9%, porcine dermal collagen in 39.9% and bovine pericardium in 5.2%. In 45.1% of cases the prostheses were cross-linked. Techniques used for ventral-incisional hernias were as follows: onlay in 3.6%, inlay in 5.5%, sublay in 62.7% and underlay via laparoscopy in 28.2%. The mean overlap was 4.1 cm (SD ±1.2). No intestinal anastomosis was necessary in 65.3% of cases; however, small/large bowel resection and anastomoses were necessary in 22.3 and 12.4% of cases, respectively. Intraoperative blood transfusion was necessary in 10.4% of procedures. The skin was completely closed in 84% of procedures. At the 1-month follow-up, there were no complications in 54.4% of cases. Among the cases with complications, 10 patients (5.8%) experienced recurrence, and the postoperative readmission rate was 12.9%. The average visual analog scale (VAS) score for pain was 2.9 (SD ±1.2) at rest. At the 1-year follow-up, there were no complications in 96.4% of cases. Two patients experienced recurrence, and the postoperative readmission rate was 3.6%. The average VAS score for pain was 1.8 (SD ±0.8) at rest.

CONCLUSIONS

This register shows that BPs are highly versatile and can be used in either open or laparoscopic surgery in all kinds of patients and in contaminated surgical fields. However, due to the very good outcomes of synthetic meshes and the high costs of BPs, the latter should only be used in selected cases.

The use of porcine small intestine submucosa implants might be associated with a high recurrence rate following laparoscopic herniorrhaphy

BACKGROUND/PURPOSE

The efficacy of porcine small intestine submucosa (SIS) implants in hernia repair has rarely been reported and remained elusive. We herein report our experience to further elucidate the efficacy of SIS mesh in herniorrhaphy.

METHODS

Between June 2008 and October 2009, a total of 82 patients with 125 inguinal hernias undergoing endoscopic total extraperitoneal (TEP) herniorrhaphy were included. Seventy patients (with 108 hernias) had traditional polypropylene and 12 patients (with 17 hernias) had SIS mesh repair. Postoperative complications and recurrence rates were compared between the two meshes.

RESULTS

The demographics between two groups were similar. All operations were performed smoothly with laparoscopy, and the postoperative courses were uneventful. After a median follow-up of 18 months, five (7%) in the polypropylene group and three (25%) in the SIS group had chronic pain (p = 0.09). Five of 17 (29.4%) hernia repairs in the SIS group had an ipsilateral recurrence, compared to no recurrence in the polypropylene group. In the five cases, the second laparoscopy revealed the SIS mesh had been totally degraded and there was no obvious fibrotic tissue in the previous mesh sites.

CONCLUSION

Our data suggest that the use of SIS mesh in endoscopic TEP herniorrhaphy might be associated with a high recurrence rate. The second look laparoscopy in these recurrent cases revealed slow and inadequate integration of host tissue. More evidence is still required to further evaluate the efficacy of SIS mesh in endoscopic TEP herniorrhaphy.

Abdominal wall defect repair with biological prosthesis in transplanted patients: single center retrospective analysis and review of the literature

The risk of fascial dehiscence, wound infection and incisional hernias in organ recipients is higher. Retrospective analysis of our departments database, checking the last 12 years (2000-2012), and of the literature (1966-2012) were conducted. In our database we found seven patients: five liver (71.4 %), one kidney (14.3 %), one multivisceral (14.3 %); five males (71.4 %), two females (28.6 %). Five (71.4 %) were operated in urgency setting and two in ordinary setting (28.6 %). The mean/median number of laparotomies before the incisional hernia is of 2.1/1 (range 1-5). In five patients swine intestinal submucosa (71.4 %) have been used and in two porcine dermal collagen (28.6 %). The mean/median age was 48.3/52 years (range 18-61). The mean/median body mass index was 26.7/27 (range 19-34). The mean/median for follow-up after intervention was 40.1/33 months (range 50-21). Recurrence rate was 14.3 %. Complication rate was 28.6 %. Adding the present report, the literature reports 70 cases. 20 % of prosthesis have been implanted inlay, 25.7 % underlay, in 5.7 % intraperitoneal and in 48.6 % were not specified. The mean age ranges from 0.7 to 48.3 years. Kidney, liver, pancreas, bowel and multivisceral transplant are reported. Porcine dermal collagen has been implanted in 24.3 %, human dermal collagen in 51.4 % and swine intestinal submucosa in 24.3 %. The immunosuppression regimens comprehend variable associations of tacrolimus, steroids, mycophenolate mofetil, sirolimus, thymoglobulin, azathioprine/basiliximab and daclizumab. The mean follow-up is 16.2 months. The mean complication rate is 9.4 %. Biological prosthesis seems to be useful and safe in abdominal wall repair surgery in transplanted patients.

Thoracic wall reconstruction with Collamend® in trauma: report of a case and review of the literature

INTRODUCTION

Despite progress in reconstructive techniques, rebuilding portions of the thorax remains challenging, in particular when large resections, contamination or infection are involved. No other cases of thoracic reconstruction in trauma patients with biological prosthesis have been described since now.

METHODS

We report a case of thoracic reconstruction in highly infected field in a trauma patient. We also performed a literature review about the topic.

CONCLUSION

Collamend® demonstrated its usefulness in thoracic wall reconstruction even in trauma patients and infected fields.

Bupivacaine-enhanced small intestinal submucosa biomaterial as a hernia repair device

Management of post-surgical pain following herniorrhaphy remains a clinical challenge and novel methods to deliver analgesic compounds could be of great benefit. Because there is great interest in the use of natural biomaterials for hernia repair, we investigated the biocompatibility of a natural biomaterial, porcine small intestinal submucosa (SIS), which was impregnated with bupivacaine (SIS-B) via immersion in a solution of poly(lactic-co-glycolic acid) (PLGA). Groups of Sprague Dawley rats underwent surgical creation of a ventral abdominal wall defect with subsequent repair using either SIS or SIS-B. Analysis of serial blood samples showed peak bupivacaine levels (83 ng/mL) were achieved 16 h after implantation of SIS-B. One month after surgery, the rats were euthanized and implant sites harvested for mechanical strength testing and histological analysis. At the time of necropsy, adhesion extent and tenacity was greater in SIS-B rats, with 90% of SIS-B rats have adhesion to the implant site compared to only 75% of SIS rats. Microscopically, SIS implant sites were characterized by small amounts of residual SIS surrounded by mild-to-moderate chronic inflammation. In contrast, rats treated with SIS-B, residual SIS-B was surrounded by a ring of acute inflammatory cells and an outer ring of chronic inflammatory cells, possibly due to bupivacaine or residual PLGA. Mechanical strength testing of the harvested implant sites showed no significant (p ≤ 0.05) difference between SIS and SIS-B implants. In summary, bupivacaine is readily elaborated from SIS-B; and impregnation of SIS with bupivacaine does not substantially alter the biocompatibility of the biomaterial or its mechanical strength following implantation.

Biological mesh for abdominal wall hernia synthetic mesh multidrug-resistant Pseudomonas aeruginosa infection: report of a case

The use of biological mesh for the treatment of synthetic mesh-related infections in patients who undergo ventral hernia repair has been considered over the past few years. Removal of the infected synthetic mesh, which may be required in such cases, can result in recurring herniation. Biological implants have thus been recently used for the reconstruction of the existing defect. We herein present the case of a patient who developed multidrug-resistant Pseudomonas aeruginosa synthetic mesh infection following hernia repair, which was managed by the removal of the material and the application of a biological mesh in the contaminated area.

A rabbit model of peripheral compartment syndrome with associated rhabdomyolysis and a regenerative medicine approach for treatment

Peripheral compartment syndrome (PCS) has a complex etiology, with limited treatment options and high patient morbidity. Animal models of PCS have been hampered by differences in cross-species anatomy, physiology, and the relative rarity of the naturally occurring syndrome in animals. In the present study, the combination of saline infusion with intermittent crushing of skeletal muscle consistently caused increased intracompartmental pressure, hypocalemia, and hypercreatinine-phophokinasemia, signs diagnostic of PCS. This method was used to evaluate both the standard PCS treatment, specifically a fasciotomy, and a regenerative medicine approach for treatment-consisting of a fasciotomy with local administration of a biologic scaffold material composed of porcine small intestinal submucosa extracellular matrix (SIS-ECM). The use of this SIS-ECM scaffold in conjunction with a fasciotomy was associated with myogenesis and constructive tissue remodeling in the SIS-ECM-treated animals. At 1 and 3 months after treatment innervated muscle tissue was present at the site of injury. No myogenesis was present in the fasciotomy only treated animals. RAM11+ macrophages, which are associated with constructive tissue remodeling, were present within the injury site in the SIS-ECM-treated animals at 1 month. The present study provides a reproducible animal model with which to study PCS, and shows the potential of a regenerative medicine approach to PCS treatment.

A prospective, randomized trial of esophageal submucosal tunnel closure with a stent versus no closure to secure a transesophageal natural orifice transluminal endoscopic surgery access site

BACKGROUND

Secure esophagotomy closure methods are a critical element in the advancement of transesophageal natural orifice transluminal endoscopic surgery (NOTES) procedures.

OBJECTIVE

To compare the clinical outcomes in swine receiving an esophageal stent or no stent after a submucosal tunnel NOTES access procedure.

DESIGN

Prospective, randomized, controlled trial in 10 Yorkshire swine.

SETTING

Academic center.

INTERVENTION

An endoscopic mucosectomy device was used to create an esophageal mucosal defect. An endoscope was advanced through a submucosal tunnel into the mediastinum and thorax, and diagnostic mediastinoscopy and thoracoscopy were performed. Ten animals were randomized to no stenting (n = 5) or stenting (n = 5) with a prototype small-intestine submucosa-covered stent.

MAIN OUTCOME MEASUREMENTS

Gross and histologic appearance of the mucosectomy and esophagotomy sites as well as clinical outcomes.

RESULTS

There was a significant difference in the overall procedure time between the animals that received a stent (35.0 min, range 27-46.0 min) and those with no closure (19.0 min, range 17-32 min) (P value = .018). The unstented group achieved endoscopic and histologic evidence of complete re-epithelialization and healing (100%) at the mucosectomy site compared with the stented group (20%, P = .048). Stent migration into the stomach occurred in two swine. Both groups had complete closure of the submucosal tunnel and well-healed esophagotomy sites.

LIMITATIONS

Animal study, small number of subjects.

CONCLUSION

The placement of a covered esophageal stent significantly interferes with mucosectomy site healing.

Biological Mesh in Hernia Repair, Abdominal Wall Defects, and Reconstruction and Treatment of Pelvic Organ Prolapse: A Review of the Clinical Evidence

The use of biological meshes seems to be an innovation that influences all surgical fields. The existing evidence indicates that biological meshes cannot only be applied on the area of hernia repair, but also on cases of abdominal reconstruction and pelvic organ prolapse treatment, especially in the presence of contaminated or potentially contaminated surgical fields. Low risks of graft rejection, complications, and infection seem to be the main advantages of biological meshes in comparison with the synthetic nonabsorbable ones. Nevertheless, the elevated costs suggest that biological mesh implantation should be evaluated in correlation to the needs of each clinical case.

Umbilical Herniorrhaphy Reinforced with Biologic Mesh

The true recurrence rate after umbilical hernia repair in not known. After simple closure, the reported rate of recurrence in the literature is as high as 54 per cent. With synthetic mesh repair, the recurrence rates are lowered to less than 10 per cent. However, synthetic mesh is associated with complications such as enterocutaneous fistula and mesh infections. This preliminary study looks at the safety and effectiveness of biologic extracellular matrix mesh reinforcement in the repair of umbilical hernias. We retrospectively reviewed all patients who underwent repair of an umbilical hernia defect (2-3 cm) with primary approximation of the margins and reinforced using a biologic mesh placed beneath the umbilical fascia from 2007 to 2009. Demographic data were collected. Patients were followed prospectively at 2 weeks, 8 weeks, 6 months, and 1 year. Data were reviewed for postoperative complications, hernia recurrence, and patient satisfaction. During the study period, 16 patients completed the 1 year follow-up. There were 10 men and six women. Ages ranged from 28 to 75 years with a mean age of 47.6 years. The hernias were 2 to 3 cm in size. Complications were minimal. Overall patient satisfaction with the procedure was high. There were no mesh infections. During a mean follow-up of 12 months, only one patient had recurrent hernia (6%). This preliminary evaluation shows promise for an alternative treatment of umbilical hernias using biologic extracellular matrix mesh added as an underlay to reinforce a primary closure. The biologic mesh has a low incidence of infection and complications and results in high patient satisfaction. This preliminary study begs for a randomized, prospective evaluation with long-term follow-up.

Adhesive performance of biomimetic adhesive-coated biologic scaffolds

Surgical repair of a discontinuity in traumatized or degenerated soft tissues is traditionally accomplished using sutures. A current trend is to reinforce this primary repair with surgical grafts, meshes, or patches secured with perforating mechanical devices (i.e., sutures, staples, or tacks). These fixation methods frequently lead to chronic pain and mesh detachment. We developed a series of biodegradable adhesive polymers that are synthetic mimics of mussel adhesive proteins (MAPs), composed of 3,4-dihydroxyphenylalanine (DOPA)-derivatives, polyethylene glycol (PEG), and polycaprolactone (PCL). These polymers can be cast into films, and their mechanical properties, extent of swelling, and degradation rate can be tailored through the composition of the polymers as well as blending with additives. When coated onto a biologic mesh used for hernia repair, these adhesive constructs demonstrated adhesive strengths significantly higher than fibrin glue. With further development, a precoated bioadhesive mesh may represent a new surgical option for soft tissue repair.

Stent placement provides safe esophageal closure in thoracic NOTES(TM) procedures

BACKGROUND

Safe esophageal closure remains a challenge in transesophageal Natural Orifice Transluminal Endoscopic Surgery (NOTES). Previously described methods, such as suturing devices, clips, or submucosal tunneling, all have weaknesses. In this survival animal series, we demonstrate safe esophageal closure with a prototype retrievable, antimigration stent.

METHODS

Nine Yorkshire swine underwent thoracic NOTES procedures. A double-channel gastroscope equipped with a mucosectomy device was used to create an esophageal mucosal defect. A 5-cm submucosal tunnel was created and the muscular esophageal wall was incised with a needle-knife. Mediastinoscopy and thoracoscopy were performed in all swine; lymphadenectomy was performed in seven swine. A prototype small intestinal submucosal (SurgiSIS(®)) covered stent was deployed over the mucosectomy site and tunnel. Three versions of the prototype stent were developed. Prenecropsy endoscopy confirmed stent location and permitted stent retrieval. Explanted esophagi were sent to pathology.

RESULTS

Esophageal stenting was successful in all animals. Stent placement took 15.8 ± 4.8 minuted and no stent migration occurred. Prenecropsy endoscopy revealed proximal ingrowth of esophageal mucosa and erosion with Stent A. Mucosal inflammation and erosion was observed proximally with Stent B. No esophageal erosion or pressure damage from proximal radial forces was seen with Stent C. On necropsy, swine 5 had a 0.5-cm periesophageal abscess. Histology revealed a localized inflammatory lesion at the esophageal exit site in swine 1, 3, and 9. The mucosectomy site was partially healed in three swine and poorly healed in six. All swine thrived clinically, except for a brief period of mild lethargy in swine 9 who improved with short-term antibiotic therapy. The submucosal tunnels were completely healed and no esophageal bleeding or stricture formation was observed. All swine survived 13.8 ± 0.4 days and gained weight in the postoperative period.

CONCLUSIONS

Esophageal stenting provides safe closure for NOTES thoracic procedures but may impede healing of the mucosectomy site.

A porcine-derived acellular dermal scaffold that supports soft tissue regeneration: removal of terminal galactose-alpha-(1,3)-galactose and retention of matrix structure

Sub-optimal clinical outcomes after implantation of animal-derived tissue matrices may be attributed to the nature of the processing of the material or to an immune response elicited in response to xenogeneic epitopes. The ability to produce a porcine-derived graft that retains the structural integrity of the extracellular matrix and minimizes potential antigenic response to galactose-alpha-(1,3)-galactose terminal disaccharide (alpha-Gal) may allow the scaffold to support regeneration of native tissue. Dermal tissue from wild-type (WT-porcine-derived acellular dermal matrix [PADM]) or Gal-deficient (Gal(-/-) PADM) pigs was processed to remove cells and DNA while preserving the structural integrity of the extracellular matrix. In addition, the WT tissue was subjected to an enzymatic treatment to minimize the presence of alpha-Gal (Gal-reduced PADM). Extracellular matrix composition and integrity was assessed by histological, immunohistochemical (IHC), and ultrastructural analysis. In vivo performance was evaluated by implantation into the abdominal wall of Old World primates in an exisional repair model. Anti-alpha-Gal activity in the serum of monkeys implanted subcutaneously was assessed by ELISA. Minimal modification to the extracellular matrix was assessed by evaluation of intact structure as demonstrated by staining patterns for type I and type VII collagens, laminin, and fibronectin similar to native porcine skin tissues. Explants from the abdominal wall showed evidence of remodeling, notably fibroblast cell repopulation and revascularization, as early as 1 month. Serum ELISA revealed an initial anti-alpha-Gal induction that decreased to baseline levels over time in the primates implanted with WT-PADM, whereas no or minimal anti-Gal activity was detected in the primates implanted with Gal(-/-) PADM or Gal-reduced PADM. The combination of a nondamaging process, successful removal of cells, and reduction of xenogeneic alpha-Gal antigens from the porcine dermal matrix are critical for producing a material with the ability to remodel and integrate into host tissue and ultimately support soft tissue regeneration.

Retention of structural and biochemical integrity in a biological mesh supports tissue remodeling in a primate abdominal wall model

AIM

Suboptimal clinical outcome following the implantation of porcine-derived tissue matrices may be due to the method of processing the material to achieve an acellular graft and to reduce the immune response to xenogeneic epitopes. The ability to produce a porcine-based graft material that retains the structural integrity of the extracellular matrix and minimizes the potential antigenic response to the galactose-alpha(1,3)-galactose terminal disaccharide (alpha-Gal) may allow the scaffold to support regeneration of native tissue.

MATERIALS & METHODS

Porcine dermal tissue was processed to remove cells and DNA, and minimize the presence of alpha-Gal via specific enzymatic cleavage. In vivo performance was evaluated by implantation into the abdominal wall of an Old World primate exisional repair model. Grafts were explanted at 0.5, 1, 3 and 6 months and assessed for cellular repopulation and vascularization, for localized immune response by presence of T cells, B cells and macrophages, and systemic immune response by anti-alpha-Gal IgG by ELISA.

RESULTS

Animals tolerated implants well and exhibited no clinical signs of inflammation, laxity, hernia or visceral tissue attachment. Histological evaluation revealed marked host fibroblast repopulation and neoangiogenesis as early as 2 weeks postimplant. Cellular repopulation and maturation of vascular structures reached a plateau at 3 months. Immunological evaluation of immune cell infiltration demonstrated an early, mixed cellular inflammatory response at 2 weeks. This cellular immune response was transient and diminished to baseline levels by 3 months postimplant.

CONCLUSION

The combination of a nondamaging process, successful removal of cells, and reduction of the xenogeneic alpha-Gal antigens from the porcine dermal matrix, while maintaining an intact extracellular matrix, is critical to its ability to remodel and integrate into host tissue, leading to its overall acceptance.

Definitive abdominal wall closure using a porcine intestinal submucosa biodegradable membrane in pediatric transplantation

Abdominal closure in children less than 10 kg following liver or kidney transplantation can be challenging. Excessive pressure attained from a tight closure can result in abdominal compartment syndrome, graft compromise and loss. Concerns over using prosthetic patches are that of infection and dehiscence. We report a series of definitive abdominal wall closure using a biodegradable membrane from porcine intestinal submucosa (Surgisis; Cook Biotech Incorporated, West Lafayette, IN, USA). A prospective collection and follow up of liver and kidney transplant patients weighing less than 10 kg who required abdominal wall augmentation with Surgisis in order to achieve satisfactory closure. There were 10 liver and two renal transplant patients. The average weight of the liver transplant patients was 6.6 kg (5.4-8.5 kg) and the renal 9.8 kg. The average area of Surgisis used was 71.2 cm(2) (25-160 cm(2)) and length of follow up was 15.3 months (1-27 months). Concomitant measures to aid abdominal closure included bilateral recipient nephrectomy for the renal patients and reduction by 33% of the lateral segmental grafts in two liver transplant patients. Delayed closure occurred in all patients except one and the average days to closure from the first surgery was 3.75 days (0-6 days). Following liver transplantation one patient died from multiple organ failure at one month secondary to hemophagocytosis from underlying combined immune deficiency syndrome and one patient with hepatic artery thrombosis was salvaged at re-exploration. There were two wound complications, one patient developed two small sinuses and some skin dehiscence which healed over four months and the second developed a skin sinus following trans-patch liver biopsy which healed in three wk. Both had positive microbial cultures but neither necessitated removal of the graft. There were no incisional hernias. Surgisis is a safe method for facilitating abdominal closure in pediatric transplant patients. It appears to have long-term durability with no incisional hernias on short- and medium-term follow up, and is fairly resistant to infection.

Inguinal hernia repair with porcine small intestine submucosa: 3-year follow-up results of a randomized controlled trial of Lichtenstein's repair with polypropylene mesh versus Surgisis Inguinal Hernia Matrix

BACKGROUND

The aim of this study was to evaluate the safety and efficacy of Lichtenstein's hernioplasty using Surgisis Inguinal Hernia Matrix (SIHM; Cook, Bloomington, Indiana) compared with polypropylene (PP; Angiologica, Pavia, Italy).

METHODS

This was a prospective, randomized, double-blind trial comparing Lichtenstein's inguinal hernioplasty using SIHM versus PP.

RESULTS

Seventy male patients underwent Lichtenstein's hernioplasty (n = 35 in the SIHM group and n = 35 in the PP group). At 3 years after surgery, there were 2 deaths (5.7%) in the PP group and 1 death (2.9%) in the SIHM group (not significant [NS]). Although the study was underpowered to evaluate the recurrence rate, only 1 recurrence (2.9%) was seen in the PP group (NS). Although a significant decrease in postsurgical pain incidence was never observed among patients in the SIHM group, a significantly lower degree of pain was detected at rest and on coughing at 1, 3, and 6 months and on movement at 1, 3, and 6 months and 1, 2, and 3 years. A significant decrease in postsurgical incidence and degree of discomfort when coughing and moving were observed among patients in the SIHM group at 3 and 6 months and at 1, 2, and 3 years after surgery.

COMMENTS

SIHM hernioplasty seems to be a safe and effective procedure.

Transgastric placement of biologic mesh to the anterior abdominal wall

BACKGROUND

Incisional hernia repairs have a risk of wound complications that may be decreased using a natural orifice transluminal endoscopic surgery (NOTES) approach. The aim of this study was to determine the feasibility and safety of transgastric mesh placement to the anterior abdominal wall in a porcine model as a precursor to future studies of NOTES ventral hernia repair.

METHODS

The procedure was done under sterile conditions with a double lumen endoscope using a plastic overtube. The endoscope was placed in the stomach preloaded with an overtube. Entrance of the endoscope and overtube into the peritoneal cavity was performed with the percutaneous endoscopic gastrostomy (PEG) technique. A 13 x 15 cm Surgisis Gold mesh with four corner sutures was delivered through the overtube. Transfascial suture passer and endoscopic grasper were used to externalize the sutures and attach the mesh to the anterior abdominal wall. The gastrotomy was closed with a transabdominal gastropexy. The pigs were sacrificed at 2 weeks.

RESULTS

Mesh placement was performed in five pigs. Operative time was 215 min (standard deviation, SD 99 min). The most difficult portion of the procedure involved manipulating the gastric overtube, likely exposing the mesh to bacteria in the stomach. Culture-positive abscesses were present at the mesh in 3/5 animals. The mesh appeared intact in 4/5 animals; one of the infected meshes had delamination of 50% of the mesh. Adhesions to the mesh surface varied from 2% to 100%. At 2 weeks, median mesh size was 116 cm2 (range 96-166 cm2) and median contraction was 41% (range 15-51%). Histologic evaluations demonstrated marked inflammation and fibrosis progressing into the mesh material.

CONCLUSIONS

Totally endoscopic transgastric delivery and fixation of a biologic mesh to the anterior abdominal wall is feasible. Challenges remain in designing systems for mesh delivery that exclude gastric content. Once these problems can be surmounted NOTES ventral hernia repair may become an option in man.

Are biologic grafts effective for hernia repair?: a systematic review of the literature

Biologic grafts for hernia repair are a relatively new development in the world of surgery. A thorough search of the Medline database for uses of various biologic grafts in hernia shows that the evidence behind their application is plentiful in some areas (ventral, inguinal) and nearly absent in others (parastomal). The assumption that these materials are only suited for contaminated or potentially contaminated surgical fields is not borne out in the literature, with more than 4 times the experience being reported in clean fields and the average success rates being higher (93% vs 87%). Outcomes prove to be highly dependent on material source, processing methods and implant scenarios with failure rates ranging from zero to more than 30%. Small intestinal submucosa (SIS) grafts have an aggregate failure rate of 6.7% at 19 months whereas acellular human dermis (AHD) grafts have a failure rate of 13.6% at 12 months. Chemically cross-linked grafts have much less published data than the non-cross-linked materials. In particular, the search found 33 articles for SIS, 32 for AHD, and 13 for cross-linked porcine dermis. Furthermore, the cumulative level of evidence for each graft material was fairly low (2.6 to 2.9), and only 1 material (SIS) had level 1 evidence reported in any hernia type (inguinal and hiatal). Together, biologic grafts have published evidence showing success rates better than 90% overall and more than 2000 years of cumulative implant time. Improvements in materials, techniques, and patient selection are likely to improve these numbers as this field of surgery matures.

Prosthetic abdominal wall hernia repair in emergency surgery: from polypropylene to biological meshes

The use of nonabsorbable prosthetic materials such as polypropylene, polyester, and ePTFE, have expanded and are now widely used in reparative surgery for abdominal wall hernias.There are still difficulties to find correct indication for prosthetic implant in emergency hernia surgery: as a matter of fact there is still a great debate if to use non-absorbable prostheses in potentially or truly infected operating fields [e.g. after intestinal resections].All these problems can be avoided with the use of absorbable prosthetic materials such as those composed of lactic acid polymers or lactic and glycolic acid copolymers: however, the use of these absorbable prosthesis exposes the patient to a rapid and inevitable hernia recurrence.It is important to remember that prosthetic repair has been proven to have a significant less risk of recurrence than repair with direct sutures.Recently, new "biologic" prosthetic materials have been developed and proposed for the clinical use in infected fields. These materials can be called "remodeling" for the way by which they are replaced after their placement within the patient. The "remodeling" process is made possible through a process of incorporation, where a reproduction of a site-specific tissue similar to the original host tissue is created.

Scaffolding in tissue engineering: general approaches and tissue-specific considerations

Scaffolds represent important components for tissue engineering. However, researchers often encounter an enormous variety of choices when selecting scaffolds for tissue engineering. This paper aims to review the functions of scaffolds and the major scaffolding approaches as important guidelines for selecting scaffolds and discuss the tissue-specific considerations for scaffolding, using intervertebral disc as an example.

New "biological" meshes: the need for a register. The EHS Registry for Biological Prostheses: call for participating European surgeons

Non-absorbable prosthetic materials in hernia surgery can cause relatively rare complications, which include chronic pain, a feeling of stiffness with reduced compliance of the abdominal wall, prosthetic erosion/fistulisation and an increased risk of persistent deep infection. Recently, to avoid these problems, new "biological" prosthetic materials have been developed and proposed for clinical use. These materials are all essentially composed of an extracellular matrix stripped of its cellular components, and differ substantially only in their source (porcine small intestine submucosa, porcine dermis or cadaveric human dermis). Because of the numerous variables involved, it is very difficult to conduct a randomised controlled trial. Therefore, the European Hernia Society (EHS) has decided to start the EHS Registry for Biological Prostheses (ERBP). This is a prospective registry in Europe on the use of collagen meshes in (potentially) contaminated circumstances or clean surgical fields. The registry intends to collect some preoperative data on the patient and indication, intraoperative data and outcome data.

Surgical progress in inguinal and ventral incisional hernia repair

The goals of this article are to describe the history of hernia repair and how innovations in surgical technique, prosthetics, and technology have shaped current practice.

FGF-2 enhances vascularization for adipose tissue engineering

BACKGROUND

Current therapies for soft-tissue reconstruction include autologous tissue flaps and alloplastic implants. Although autologous fat transplantation using a minimally invasive cannula harvest has less donor-site morbidity than tissue flaps, there is a variable degree of fat resorption over time. Preadipocytes isolated from harvested fat are better able to withstand the mechanical trauma from the suction cannula and subsequently may result in improved cell survival and generation of new fat tissue after transfer to another anatomic site. The authors hypothesized that particulate small intestinal submucosa could be useful as injectable cell delivery vehicles for preadipocytes, and that the release of fibroblast growth factor (FGF)-2 would enhance vascularization.

METHODS

Preadipocytes were isolated from discarded human adipose tissue and cultured on small intestinal submucosa particles in a stirred bioreactor (spinner flask). Preadipocytes attached and proliferated on small intestinal submucosa microparticles and maintained high viability over several weeks of culture. FGF-2 was encapsulated in poly(lactic-co-glycolic acid) microspheres and injected in conjunction with the preadipocyte/small intestinal submucosa particles into a mouse subcutaneous model.

RESULTS

Preadipocytes attached and proliferated on small intestinal submucosa particles in vitro. In vivo, vascularization was significantly enhanced with the incorporation of FGF-2-loaded poly(lactic-co-glycolic acid) microspheres. In addition, cell survival during the 14-day in vivo observation period was confirmed by fluorescent dye labeling.

CONCLUSIONS

Small intestinal submucosa particles are a favorable scaffold for preadipocytes, allowing ex vivo proliferation on particles small enough to be injected. Delivery of FGF-2 from poly(lactic-co-glycolic acid) microspheres resulted in cell survival and enhanced vascularization.