Peritoneal adhesions to prosthetic materials: an experimental comparative study of treated and untreated polypropylene meshes placed in the abdominal cavity

Facile Surface Modification with Croconaine-Functionalized Polymer on Polypropylene for Antifouling and NIR-Light-Mediated Photothermal Sterilization

Biomedical-device-associated infection (BAI) is undoubtedly a major concern and a serious challenge in modern medicine. Therefore, the development of biomedical materials that are capable of resisting or killing bacteria is of great importance. In this work, a croconaine-functionalized polymer with antifouling and near-infrared (NIR) photothermal bactericidal properties was prepared and facilely modified on polypropylene (PP) to combat medical device infections. Croconaine dye is elaborately modified as a "living" initiator, termed CR-4EBiB, for preparing amphiphilic block polymers by atom transfer radical polymerization (ATRP). In the formed polymer coating, the hydrophobic block can strongly adhere to the surface of the PP substrate, whereas the hydrophilic block is located on the outer layer by solvent-induced resistance to bacterial adhesion. Under the irradiation of an NIR laser (808 nm), the croconaine dye in the coating achieved maximum conversion of light to heat to effectively kill E. coli, S. aureus, and methicillin-resistant Staphylococcus aureus (MRSA). This work provides a facile and promising strategy for the development of implantable antibacterial biomedical materials.

Are Surgeons Going to Be Left Holding the Bag? Incisional Hernia Repair and Intra-Peritoneal Non-Absorbable Mesh Implant Complications

Ventral incisional hernias are common indications for elective repair and frequently complicated by recurrence. Surgical meshes, which may be synthetic, bio-synthetic, or biological, decrease recurrence and, resultingly, their use has become standard. While most patients are greatly benefited, mesh represents a permanently implanted foreign body. Mesh may be implanted within the intra-peritoneal, preperitoneal, retrorectus, inlay, or onlay anatomic positions. Meshes may be associated with complications that may be early or late and range from minor to severe. Long-term complications with intra-peritoneal synthetic mesh (IPSM) in apposition to the viscera are particularly at risk for adhesions and potential enteric fistula formation. The overall rate of such complications is difficult to appreciate due to poor long-term follow-up data, although it behooves surgeons to understand these risks as they are the ones who implant these devices. All surgeons need to be aware that meshes are commercial devices that are delivered into their operating room without scientific evidence of efficacy or even safety due to the unique regulatory practices that distinguish medical devices from medications. Thus, surgeons must continue to advocate for more stringent oversight and improved scientific evaluation to serve our patients properly and protect the patient-surgeon relationship as the only rationale long-term strategy to avoid ongoing complications.

Prevention of Post-Operative Adhesions: A Comprehensive Review of Present and Emerging Strategies

Post-operative adhesions affect patients undergoing all types of surgeries. They are associated with serious complications, including higher risk of morbidity and mortality. Given increased hospitalization, longer operative times, and longer length of hospital stay, post-surgical adhesions also pose a great financial burden. Although our knowledge of some of the underlying mechanisms driving adhesion formation has significantly improved over the past two decades, literature has yet to fully explain the pathogenesis and etiology of post-surgical adhesions. As a result, finding an ideal preventative strategy and leveraging appropriate tissue engineering strategies has proven to be difficult. Different products have been developed and enjoyed various levels of success along the translational tissue engineering research spectrum, but their clinical translation has been limited. Herein, we comprehensively review the agents and products that have been developed to mitigate post-operative adhesion formation. We also assess emerging strategies that aid in facilitating precision and personalized medicine to improve outcomes for patients and our healthcare system.

Well-Defined Gold Nanorod/Polymer Hybrid Coating with Inherent Antifouling and Photothermal Bactericidal Properties for Treating an Infected Hernia

Biomedical device-associated infection (BAI) is a great challenge in modern clinical medicine. Therefore, developing efficient antibacterial materials is significantly important and meaningful for the improvement of medical treatment and people's health. In the present work, we developed a strategy of surface functionalization for multifunctional antibacterial applications. A functionalized polyurethane (PU, a widely used biomedical material for hernia repairing) surface (PU-Au-PEG) with inherent antifouling and photothermal bactericidal properties was readily prepared based on a near-infrared (NIR)-responsive organic/inorganic hybrid coating which consists of gold nanorods (Au NRs) and polyethylene glycol (PEG). The PU-Au-PEG showed a high efficiency to resist adhesion of bacteria and exhibited effective photothermal bactericidal properties under 808 nm NIR irradiation, especially against multidrug-resistant bacteria. Furthermore, the PU-Au-PEG could inhibit biofilm formation long term. The biocompatibility of PU-Au-PEG was also proved by cytotoxicity and hemolysis tests. The in vivo photothermal antibacterial properties were first verified by a subcutaneous implantation animal model. Then, the anti-infection performance in a clinical scenario was studied with an infected hernia model. The results of animal experiment studies demonstrated excellent in vivo anti-infection performances of PU-Au-PEG. The present work provides a facile and promising approach to develop multifunctional biomedical devices.

Polypropylene meshes coated with chitosan/polyethylene glycol for the reconstruction of the abdominal wall: an experimental study in rats

ABSTRACT The aim of this study was to characterize the tissue reactions triggered by the polypropylene mesh coated with chitosan and polyethylene glycol film, and if it’s able to prevent the formation of peritoneal adhesions. Defects in the abdominal wall of rats were induced and polypropylene meshes coated with chitosan/polyethylene glycol (CPEG group, n= 12) and uncoated (PP control group, n= 12) were implanted. On the fourth and forty-fifth postoperative day the formation of adhesion and the tissue reaction to the biomaterial was evaluated through histological and histochemical analysis. The area (P= 0.01) and severity (P= 0.002) of the adhesion was significatively less in the CPEG group. On the fourth day the foreign body reaction was less intense in CPEG group (P= 0.018) and the production of collagen fibers was more intense in this group (P= 0.041). The tissue reactions caused by the biomaterials were similar on the 45th day, with the exception of the high organization of collagen fibers in the CPEG group. The CPEG meshes did not fully prevent the formation of adhesions, but minimized the severity of the process. The foreign body reaction promoted by polypropylene meshes coated with CPEG is less intense than that triggered by uncoated polypropylene meshes.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS AND CONCLUSIONS

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

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.

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.

Italian Biological Prosthesis Work-Group (IBPWG): proposal for a decisional model in using biological prosthesis

Introduction

Indications for repair of abdominal hernia are well established and widely diffused. Controversies still exist about the indication in using the different prosthetic materials and principally about the biological ones.

Material and methods

In February 2012, the Italian Biological Prosthesis Work-Group (IBPWG), counting a background of 264 biologic implants, met in Bergamo (Italy) for 1-day meeting with the aim to elaborate a decisional model on biological prosthesis use in abdominal surgery.

Results

A diagram to simplify the decisional process in using biologics has been elaborated.

Conclusion

The present score represents a first attempt to combine scientific knowledge and clinical expertise in order to offer precise indications about the kind of biological mesh to use.

Current strategies and future perspectives for intraperitoneal adhesion prevention

INTRODUCTION

The formation of peritoneal adhesions still is a relevant clinical problem after abdominal surgery. Until today, the most important clinical strategies for adhesion prevention are accurate surgical technique and the physical separation of traumatized serosal areas. Despite a variety of barriers which are available in clinical use, the optimal material has not yet been found.

DISCUSSION

Mesothelial cells play a crucial physiological role in friction less gliding of the serosa and the maintenance of anantiadhesive surface. The formation of postoperative adhesions results from a cascade of events and is regulated by various cellular and humoral factors. Therefore, optimization or functionalization of barrier materials by developments interacting with this cascade on a structural or pharmacological level could give an innovative input for future strategies in peritoneal adhesion prevention. For this purpose, the proper understanding of the formal pathogenesis of adhesion formation is essential. Based on the physiology of the serosa and the pathophysiology of adhesion formation, the available barriers in current clinical practice as well as new innovations are discussed in the present review.

Intraperitoneal adhesions--an ongoing challenge between biomedical engineering and the life sciences

Peritoneal adhesions remain a relevant clinical problem despite the currently available prophylactic barrier materials. So far, the physical separation of traumatized serosa areas using barriers represents the most important clinical strategy for adhesion prevention. However, the optimal material has not yet been found. Further optimization or pharmacological functionalization of these barriers could give an innovative input for peritoneal adhesion prevention. Therefore, a more complete understanding of pathogenesis is required. On the basis of the pathophysiology of adhesion formation the main barriers currently in clinical practice as well as new innovations are discussed in the present review. Physiologically, mesothelial cells play a decisive role in providing a frictionless gliding surface on the serosa. Adhesion formation results from a cascade of events and is regulated by a variety of cellular and humoral factors. The main clinically applied strategy for adhesion prevention is based on the use of liquid or solid adhesion barriers to separate physically any denuded tissue. Both animal and human trials have not yet been able to identify the optimal barrier to prevent adhesion formation in a sustainable way. Therefore, further developments are required for effective prevention of postoperative adhesion formation. To reach this goal the combination of structural modification and pharmacological functionalization of barrier materials should be addressed. Achieving this aim requires the interaction between basic research, materials science and clinical expertise.

Early results on the use of biomaterials as adjuvant to abdominal wall closure following cytoreduction and hyperthermic intraperitoneal chemotherapy

Background

Hyperthermic chemotherapy applies thermal energy to both abdominal wall as well as the intra-abdominal viscera. The combination of the hyperthemia, chemotherapy and cytoreductive surgery (CRS) is associated with a defined risk of abdominal wall and intestinal morbidity reported to be as high as 15%, respectively to date, no studies have evaluated the use of biomaterial mesh as adjuvant to abdominal wall closure in this group of patients. In the present report, we hypothesized that post HIPEC closure with a biomaterial can reduce abdominal wall morbidity after CRS and hyperthermic intraperitoneal chemotherapy.

Materials and methods

All patients treated with HIPEC in a tertiary care center over 12 months (2008-2009) period were included. Eight patients received cytoreductive surgery followed by HIPEC for 90 minutes using Mitomycin C (15 mg q 45 minutes × 2). Abdominal wall closure was performed using Surgisis (Cook Biotech.) mesh in an underlay position with 3 cm fascial overlap-closure. Operative time, hospital length of stay (LOS) as well as postoperative outcome with special attention to abdominal wall and bowel morbidity were assessed.

Results

Eight patients, mean age 59.7 ys (36-80) were treated according to the above protocol. The primary pathology was appendiceal mucinous adenocarcinoma (n = 3) colorectal cancer (n = 3), and ovarian cancer (n = 2). Four patients (50%) presented initially with abdominal wall morbidity including incisional ventral hernia (n = 3) and excessive abdominal wall metastatic implants (n = 1). The mean peritoneal cancer index (PCI) was 8.75. Twenty eight CRS were performed (3.5 CRS/patient). The mean operating time was 6 hours. Seven patients had no abdominal wall or bowel morbidity, the mean LOS for these patients was 8 days. During the follow up period (mean 6.3 months), one patient required exploratory laparotomy 2 weeks after surgery and subsequently developed an incisional hernia and enterocutaneous fistula.

Conclusion

The use of biomaterial mesh in concert with HIPEC enables the repair of concomitant abdominal wall hernia and facilitates abdominal wall closure following the liberal resection of abdominal wall tumors. Biomaterial mesh prevents evisceration on repeat laparotomy and resists infection in immunocompromised patients even when associated with bowel resection.

Initial experience of laparostomy with immediate vacuum therapy in patients with severe peritonitis

INTRODUCTION

To report our initial experience of laparostomy and immediate intra-abdominal vacuum therapy in patients with severe peritonitis due to intra-abdominal catastrophes.

PATIENTS AND METHODS

Twenty-seven patients underwent emergency laparotomy and laparostomy formation with the application of immediate intra-abdominal TRAC-VAC therapy (male:female ratio, 1:1.2; median age, 73 years; range, 34-84 years). Predicted mortality was assessed using the P-POSSUM score and compared with clinically observed outcomes.

RESULTS

Ten patients (37%) with a mean predicted P-POSSUM mortality of 72%, died of sepsis and multi-organ failure. Seventeen patients (mean P-POSSUM 48% expected mortality) survived to discharge. One patient with pancreatitis died from small bowel obstruction 1-year post discharge, two patients developed a small bowel fistula. One patient had an allergic reaction to the VAC dressing. Our patients, treated with laparostomy and TRAC VAC therapy, had a significantly improved observed survival when compared to P-POSSUM expected survival (P = 0.004).

CONCLUSIONS

Laparostomy with immediate intraperitoneal VAC therapy is a robust and effective system to manage patients with intra-abdominal catastrophes. There were significantly improved outcomes compared to the mortality predicted by P-POSSUM scores. Damage control surgery with laparostomy formation and intra-abdominal VAC therapy should be considered in patients with severe peritonitis.