Effect of different barriers of oxidized regenerated cellulose (ORC) on cecal and sidewall adhesions in the presence and absence of bleeding

Sprayable anti-adhesive hydrogel for peritoneal macrophage scavenging in post-surgical applications

Post-surgical adhesions frequently occur after intra-abdominal surgery, leading to severe complications. Despite the development of various types of adhesion barriers to address post-surgical adhesions, several limitations persist, including off-target localization, handling difficulties, and potential immunogenicity. Here, we report a spray-type adhesion barrier for broad, fast application, forming two sequential networks. The first network is formed by a polyelectrolyte complex of sulfated hyaluronic acid and chitosan, while the second network is established through pluronic® F127 thermogelation. This sprayable barrier served as both a physical protector for the damaged peritoneum and an immunomodulator for peritoneal macrophages, as evidenced its effectiveness in a rat ischemic button model. Taken together, this efficient adhesion barrier presents a promising solution for post-surgical adhesions.

Prevention of Adhesions after Bone Fracture Using a Carboxymethylcellulose and Polyethylene Oxide Composite Gel in Dogs

The formation of adhesions is a common complication following traumatic injuries and surgical procedures, often resulting in pain, stiffness, and loss of function. This study aimed to evaluate the feasibility and safety of using a composite material comprising of carboxymethylcellulose (CMC), polyethylene oxide (PEO), and calcium chloride, for preventing adhesions between muscle and bone during the healing stage, as well as its effect on the bone healing process. Ten healthy purpose-bred laboratory Beagle dogs were randomly subjected to two consecutive operations with a 6-month interval, alternating between left and right forelimbs. On the left forelimb an osteotomy at the ulna was performed, while on the right forelimb the same procedure was supplemented by the application of the anti-adhesion agent in the osteotomy site prior to closure. Clinical, diagnostic imaging, macroscopic, and histological evaluations were performed at various time points. The results showed no significant differences in surgical site perimeter (p = 0.558), lameness (p = 0.227), and radiographic bone healing (p = 0.379) between the two groups. However, the macroscopic (p = 0.006) and histological assessments revealed significantly lower adhesion scores (p = 0.0049) and better healing (p = 0.0102) in the group that received the anti-adhesion agent. These findings suggest that the CMC/PEO composite material is a safe and potentially effective intervention for preventing post-traumatic and post-surgical adhesions in canine patients without compromising bone healing. Further research is warranted to fully characterize the clinical benefits of this approach.

Prevention of peritoneal adhesions formation by core-shell electrospun ibuprofen-loaded PEG/silk fibrous membrane

Adhesion bands are pathological fibrous tissues that create in the middle of tissues and organs, often reasons of intestinal obstruction, and female infertility. Here, we explored the anti-adhesive and inflammatory capacities of PEG/silk and Ibuprofen-loaded PEG/Silk core-shell nanofibrous membranes, respectively. The ibuprofen-loaded Silk Fibroin-Poly ethylene Glycol (SF-PEG) core-shell membrane was fabricated by electrospinning and considered in terms of morphology, surface wettability, drug release, and degradation. To reveal the membrane capability for adhesion bands inhibition, the membrane was stitched among the abdominal partition and peritoneum and then evaluated using two scoring adhesion systems. According to results, the fibrous membrane hindered cell proliferation, and the scoring systems and pathology showed that in a rat model, Ibuprofen-loaded PEG/Silk core-shell membrane caused a lightening in post-operative adhesion bands and the low-grade inflammatory reaction in animal models. Collectively, we fabricated new ibuprofen-loaded PEG/SF membranes with anti-adhesion and anti-inflammation properties. Moreover, this core-shell electrospun fibrous membrane has not even now been used to prevent peritendinous adhesion generation.

Balance of antiperitoneal adhesion, hemostasis, and operability of compressed bilayer ultrapure alginate sponges

In surgery, both antiperitoneal adhesion barriers and hemostats with high efficiency and excellent handling are necessary. However, antiadhesion and hemostasis have been examined separately. In this study, six different ultrapure alginate bilayer sponges with thicknesses of 10, 50, 100, 200, 300, and 500 μm were fabricated via lyophilization and subsequent mechanical compression. Compression significantly enhanced mechanical strength and improved handling. Furthermore, it had a complex effect on dissolution time and contact angle. Therefore, the 100 μm compressed sponge showed the highest hemostatic activity in the liver bleeding model in mice, whereas the 200 μm sponge demonstrated the highest antiadhesion efficacy among the compressed sponges in a Pean crush hepatectomy-induced adhesion model in rats. For the first time, we systematically evaluated the effect of sponge compression on foldability, fluid absorption, mechanical strength, hemostatic effect, and antiadhesion properties. The optimum thickness of an alginate bilayer sponge by compression balances antiperitoneal adhesion and hemostasis simultaneously.

Biocompatibility pathways and mechanisms for bioactive materials: The bioactivity zone

This essay analyzes the scientific evidence that forms the basis of bioactive materials, covering the fundamental understanding of bioactivity phenomena and correlation with the mechanisms of biocompatibility of biomaterials. This is a detailed assessment of performance in areas such as bone-induction, cell adhesion, immunomodulation, thrombogenicity and antimicrobial behavior. Bioactivity is the modulation of biological activity by characteristics of the interfacial region that incorporates the material surface and the immediate local host tissue. Although the term ‘bioactive material’ is widely used and has a well understood general meaning, it would be useful now to concentrate on this interfacial region, considered as ‘the bioactivity zone’. Bioactivity phenomena are either due to topographical/micromechanical characteristics, or to biologically active species that are presented in the bioactivity zone. Examples of topographical/micromechanical effects are the modulation of the osteoblast – osteoclast balance, nanotopographical regulation of cell adhesion, and bactericidal nanostructures. Regulation of bioactivity by biologically active species include their influence, especially of metal ions, on signaling pathways in bone formation, the role of cell adhesion molecules and bioactive peptides in cell attachment, macrophage polarization by immunoregulatory molecules and antimicrobial peptides. While much experimental data exists to demonstrate the potential of such phenomena, there are considerable barriers to their effective clinical translation. This essay shows that there is solid scientific evidence of the existence of bioactivity mechanisms that are associated with some types of biomaterials, especially when the material is modified in a manner designed to specifically induce that activity.

In vivo performance of a bilayer wrap to prevent abdominal adhesions

There is a high prevalence of intra-abdominal adhesions following bowel resection, which can result in chronic pain, bowel obstruction, and morbidity. Although commercial adhesion barriers have been widely utilized for colonic resections, these barriers do not prevent anastomotic leakage resulting from reduced healing of the anastomosis, which can result in long-term health problems. To address this limitation, we have developed an adhesive bilayer wrap with selective bioactivity to simultaneously prevent intra-abdominal adhesion formation and promote anastomotic healing. Reactive electrospinning was used to generate a crosslinked gelatin mesh to serve as a cell-instructive substrate to improve anastomotic healing. A coating of poly(ethylene glycol) (PEG) foam was applied to the bioactive mesh to generate an antifouling layer and prevent intra-abdominal adhesions. After in vitro confirmation of selective bioactivity, the composite wrap was compared after 2 weeks to a commercial product (Interceed^Ⓡ) in an in vivo rat colonic abrasion model for prevention of intra-abdominal adhesions. The composite bilayer wrap was able to prevent intra-abdominal adhesions when clinical placement was maintained. The composite bilayer wrap was further modified to include tissue adhesive properties for improved efficacy. Preliminary studies indicated that the adhesive composite bilayer wrap maintained a maximum shear strength comparable to Interceed^Ⓡ and greater than fibrin glue. Overall, this work resulted in an initial proof-of-concept device that was shown to effectively prevent intra-abdominal adhesion formation in vivo. The composite bilayer wrap studied here could lead to an improved technology for improved healing of intestinal anastomoses.

Pelvic adhesions and fertility: Where are we in 2018?

Peritoneal adhesions remain a major public health problem despite the development of laparoscopy. The rules of microsurgery must be known and followed during any pelvic surgery, even in patients who no longer have a desire for pregnancy. Anti-adhesion products are numerous. All have interest, confirmed by anatomical studies showing a smaller extent or a lesser severity of adhesions associated with their use. No studies, however, show clinical benefit in terms of improved pain or postoperative fertility. Pneumoperitoneum parameters, humidification, and lower abdominal pressure should be optimized to limit peritoneal trauma. Peri-operative corticosteroids, whose benefit has been has been demonstrated in at least one randomized trial, should be systematically used.

Epidemiology and Prevention of Postsurgical Adhesions Revisited

OBJECTIVE

To provide a comprehensive review of recent epidemiologic data on the burden of adhesion-related complications and adhesion prevention. Second, we elaborate on economic considerations for the application of antiadhesion barriers.

BACKGROUND

Because the landmark SCAR studies elucidated the impact of adhesions on readmissions for long-term complications of abdominal surgery, adhesions are widely recognized as one of the most common causes for complications after abdominal surgery. Concurrently, interest in adhesion prevention revived and several new antiadhesion barriers were developed. Although these barriers have now been around for more than a decade, adhesion prevention is still seldom applied.

METHODS

The first part of this article is a narrative review evaluating the results of recent epidemiological studies on adhesion-related complications and adhesion prevention. In part II, these epidemiological data are translated into a cost model of adhesion-related complications and the potential cost-effectiveness of antiadhesion barriers is explored.

RESULTS

New epidemiologic data warrant a shift in our understanding of the socioeconomic burden of adhesion-related complications and the indications for adhesion prevention strategies. Increasing evidence from cohort studies and systematic reviews shows that difficulties during reoperations, rather than small bowel obstructions, account for the majority of adhesion-related morbidity. Laparoscopy and antiadhesion barriers have proven to reduce adhesion formation and related morbidity. The direct health care costs associated with treatment of adhesion-related complications within the first 5 years after surgery are $2350 following open surgery and $970 after laparoscopy. Costs are about 50% higher in fertile-age female patients. Application of an antiadhesion barriers could save between $328 and $680 after open surgery. After laparoscopy, the costs impact ranges from $82 in expenses to $63 of savings.

CONCLUSIONS

Adhesions are an important cause for long-term complications in both open and laparoscopic surgery. Adhesiolysis during reoperations seems to impact adhesion-related morbidity most. Routine application of antiadhesion barriers in open surgery is safe and cost-effective. Application of antiadhesion barriers can be cost-effective in selected cases of laparoscopy. More research is needed to develop barriers suitable for laparoscopic use.

Reducing the Oxidation Level of Dextran Aldehyde in a Chitosan/Dextran-Based Surgical Hydrogel Increases Biocompatibility and Decreases Antimicrobial Efficacy

A highly oxidized form of a chitosan/dextran-based hydrogel (CD-100) containing 80% oxidized dextran aldehyde (DA-100) was developed as a post-operative aid, and found to significantly prevent adhesion formation in endoscopic sinus surgery (ESS). However, the CD-100 hydrogel showed moderate in vitro cytotoxicity to mammalian cell lines, with the DA-100 found to be the cytotoxic component. In order to extend the use of the hydrogel to abdominal surgeries, reformulation using a lower oxidized DA (DA-25) was pursued. The aim of the present study was to compare the antimicrobial efficacy, in vitro biocompatibility and wound healing capacity of the highly oxidized CD-100 hydrogel with the CD-25 hydrogel. Antimicrobial studies were performed against a range of clinically relevant abdominal microorganisms using the micro-broth dilution method. Biocompatibility testing using human dermal fibroblasts was assessed via a tetrazolium reduction assay (MTT) and a wound healing model. In contrast to the original DA-100 formulation, DA-25 was found to be non-cytotoxic, and showed no overall impairment of cell migration, with wound closure occurring at 72 h. However, the lower oxidation level negatively affected the antimicrobial efficacy of the hydrogel (CD-25). Although the CD-25 hydrogel's antimicrobial efficacy and anti-fibroblast activity is decreased when compared to the original CD-100 hydrogel formulation, previous in vivo studies show that the CD-25 hydrogel remains an effective, biocompatible barrier agent in the prevention of postoperative adhesions.

Efficacy and Safety of Ultrapure Alginate-Based Anti-Adhesion Gel in Experimental Peritonitis

BACKGROUND

Intra-abdominal infection may lead to adhesion and abscess formation. An adhesion barrier can reduce these complications but also aggravate intra-peritoneal infection, causing the opposite effects. The fear of infection propagation has limited clinical adhesion barrier use in a contaminated or infected abdomen. This study evaluated both adhesion and abscess reduction and infection propagation of a new ultrapure alginate-based anti-adhesive barrier gel in a rat peritonitis model.

METHODS

In 64 male Wistar rats, bacterial peritonitis was induced via intra-abdominal injection of a mixture of sterile feces, 10(5) colony-forming units (CFU) of Escherichia coli, and 10(4) CFU of Bacteroides fragilis. Surgical debridement and peritoneal lavage were performed 1 h after inoculation. Animals were randomly allocated in equal numbers to a control group or an alginate gel group. Animals were sacrificed on day five post-operatively. Death and the presence and size of intra-abdominal abscesses were noted, and adhesions were scored. All outcomes were compared in the two groups.

RESULTS

Seventeen rats (27%) died prematurely without any difference between the groups. Of the surviving rats in the alginate gel group, 88% developed abscesses vs. 100% of the control group. There was no significant difference in the abscess scores or incidence rates of adhesion formation between the groups. The adhesion scores were lower for the alginate gel group compared with control animals (p=0.04).

CONCLUSION

Ultrapure alginate gel reduces adhesion severity but not abscesses. The gel seemed to be safe, not aggravating intra-peritoneal infection in this abdominal infection model.

Safety and efficacy of postoperative continuous intra-peritoneal wash with lactated Ringer's for minimizing post-myomectomy pelvic adhesions: a pilot clinical trial

OBJECTIVES

To assess efficacy and safety of post-operative intra-peritoneal wash with lactated Ringer's for 48h after myomectomy in reduction of adhesions compared to routine intra-operative irrigation. Study design A prospective, randomized trial that included 52 eligible participants who had undergone abdominal myomectomy. Participants were randomly allocated to a treatment group (n=26) which was subjected to continuous peritoneal wash for 48h via two intraperitoneal drains, and a control group (n=26). The incidence of de novo adhesions and their severity and extent were scored at a second-look laparoscopy 8-10 weeks postoperatively. Adhesions were graded using the local adhesion barrier scoring system score. Adverse effects were also assessed and reported.

RESULTS

There was no statistically significant difference in duration of hospital stay or in the incidence of adverse events. A significantly higher proportion of adhesion-free patients was found in the treatment group [11/23, 47.8%] compared to the control group [4/21, 19%] (P<0.01). The mean number of pelvic sites covered by adhesions was significantly lower in the treatment group than in the control group (2.2±0.3 versus 4.6±0.8, P<0.05). The total adhesion score was significantly lower in the treatment group than in the control group (2.1±0.5 versus 4.8±1.4, P<0.05) and the adhesion score was significantly lower at most of the individual anatomical sites.

CONCLUSIONS

Application of postoperative intraperitoneal wash with lactated Ringer's solution for 48h may have reasonable safety and efficacy in minimizing postoperative pelvic de novo adhesions following abdominal myomectomy.

Benefits and harms of adhesion barriers for abdominal surgery: a systematic review and meta-analysis

BACKGROUND

Formation of adhesions after peritoneal surgery results in high morbidity. Barriers to prevent adhesion are seldom applied, despite their ability to reduce the severity of adhesion formation. We evaluated the benefits and harms of four adhesion barriers that have been approved for clinical use.

METHODS

In this systematic review and meta-analysis, we searched PubMed, CENTRAL, and Embase for randomised clinical trials assessing use of oxidised regenerated cellulose, hyaluronate carboxymethylcellulose, icodextrin, or polyethylene glycol in abdominal surgery. Two researchers independently identified reports and extracted data. We compared use of a barrier with no barrier for nine predefined outcomes, graded for clinical relevance. The primary outcome was reoperation for adhesive small bowel obstruction. We assessed systematic error, random error, and design error with the error matrix approach. This study is registered with PROSPERO, number CRD42012003321.

FINDINGS

Our search returned 1840 results, from which 28 trials (5191 patients) were included in our meta-analysis. The risks of systematic and random errors were low. No trials reported data for the effect of oxidised regenerated cellulose or polyethylene glycol on reoperations for adhesive small bowel obstruction. Oxidised regenerated cellulose reduced the incidence of adhesions (relative risk [RR] 0·51, 95% CI 0·31-0·86). Some evidence suggests that hyaluronate carboxymethylcellulose reduces the incidence of reoperations for adhesive small bowel obstruction (RR 0·49, 95% CI 0·28-0·88). For icodextrin, reoperation for adhesive small bowel obstruction did not differ significantly between groups (RR 0·33, 95% CI 0·03-3·11). No barriers were associated with an increase in serious adverse events.

INTERPRETATION

Oxidised regenerated cellulose and hyaluronate carboxymethylcellulose can safely reduce clinically relevant consequences of adhesions.

FUNDING

None.

Practical implications of postoperative adhesions for preoperative consent and operative technique

Adhesions complicate most intra-peritoneal operations. Once adhesions have formed, patients are at life-long risk for complications that include small bowel obstruction, increased risks during subsequent operations and female infertility. This has two implications for the daily work of surgeons. On the one hand, surgeons need to include the risks from adhesions during pre-operative consent. On the other hand, surgeons need to use operative techniques that minimize adhesions. Therefore this review focuses on the practical implications of adhesions for preoperative consent and operative technique.

Efficacy and safety of hyaluronate membrane in the rabbit cecum-abdominal wall adhesion model

Purpose

Tissue adhesion is a well-known postsurgical phenomenon, causing pain, functional obstruction, and difficult reoperative surgery. To overcome these problems, various synthetic and natural polymer membranes have been developed as postoperative tissue adhesion barriers. However, limitation in their use has hindered its actual application. We prepared a hyaluronate membrane (HM) to evaluate its efficacy and safety as an adhesion barrier compared to a commercialized product (Interceed, Ethicon).

Methods

To evaluate the antiadhesion effect, a cecum-abdominal wall abrasion model was adopted in a rabbit. The denuded cecum was covered by Interceed or HM or neither and apposed to the abdominal wall (each, n = 10). Four weeks after surgery, the level of adhesion was graded. Acute and chronic toxicity of the three groups were also evaluated.

Results

Blood samples drawn to evaluate acute toxicity at postoperative day 3 and 7 showed no significant difference among the three groups. The grade and area of adhesion were significantly lower in the HM compared to those of the control and Interceed at four weeks after surgery. Histologic evaluations, which was carried out to estimate tissue reactions at the site of application, as well as to assess chronic toxicity for the major organs, were not significantly different in the three groups.

Conclusion

This study showed that the antiadhesion efficacy of HM was superior to commercialized antiadhesion membrane, Interceed. Low inflammatory response and nontoxicity were also demonstrated. From these results, we suggest that the HM is a good candidate as a tissue adhesion barrier.

Cotton-Derived Oxidized Cellulose in Minimally Invasive Thoracic Surgery

Objective

The aim of this study was to identify resorption, clinical performance, and safety of cotton-derived oxidized cellulose gauze applied as a hemostat in minimally invasive oncologic thoracic surgery.

Methods

This is a pilot prospective noncomparative observational human in vivo study. A piece of cotton-derived oxidized cellulose gauze measuring 5 × 20 cm was inserted into the subcarinal space of patients with potentially resectable lung carcinoma at the time of video-assisted mediastinoscopic lymphadenectomy and reexamined several days later for macroscopic and histologic evaluation at the time of subsequent lung resection. The primary endpoint was the local situation at the implantation site described by cellulose remnants, fluid collections, and adhesions. The secondary endpoint was safety, described by the number of adverse events and surgical reinterventions.

Results

Twenty-five consecutive eligible patients with potentially resectable lung carcinoma were included. The desired hemostatic effect was achieved in all cases. No adverse events were observed. At re-exploration 10.5 (5–28) days later, the cellulose gauze was found to lose its solid structure from the fifth day on. Remnants were last detected 14 days after insertion. The implantation site exhibited no inflammatory changes and a remarkable small amount of fluid collections and adhesions.

Conclusions

Mediastinal application of cotton-derived oxidized cellulose is safe and effective. A piece of gauze measuring 5 × 20 cm seems to be absorbed completely within 15 days, thus precluding any interference with oncologic restaging and follow-up. The absence of relevant adhesions facilitates further surgical procedures. Larger comparative confirmatory studies are required. For large-scale resorption studies, our clinical model should be translated into a porcine model.

New hepatectomy-induced postoperative adhesion model in rats, and evaluation of the efficacy of anti-adhesion materials

PURPOSE

Repeated hepatic resections are not uncommon during the surgical management of liver tumors. Postoperative adhesions induced by hepatectomies can have a significant negative impact on subsequent surgeries. We recently developed a new hepatectomy-induced postoperative adhesion animal model to evaluate the anti-adhesion efficacy of commercially available sheet materials (Seprafilm(®) and Interceed(®)) and the recently reported hyaluronan-based in situ cross-linkable hydrogels.

METHODS

The median lobe (ML) and the left lateral lobe (LLL) of the liver (approximately 70 % of the total liver) of 43 male Sprague-Dawley rats were resected based on the classical procedure; anti-adhesion materials were then applied. A relaparotomy was performed 1 week later to evaluate the adhesions and histopathological findings.

RESULTS

The rats without the application of anti-adhesion materials (n = 14) showed the most severe adhesions (grade 3) between the cut surface of the liver and the small bowel or omentum. All the barrier materials produced slight anti-adhesion effects. Adhesions between the liver surface and the diaphragm and adhesions around the hepatic hilum were less severe, but were not remarkably reduced, by the anti-adhesion materials.

CONCLUSION

We successfully established a new hepatectomy-induced animal adhesion model, which may be useful for the development of new anti-adhesion materials.

Novel powdered anti-adhesion material: preventing postoperative intra-abdominal adhesions in a rat model

BACKGROUND

Although laparoscopic surgery has decreased postoperative adhesions, complications induced by adhesions are still of great concern. The aim of this study was to investigate the anti-adhesive effects of a novel powdered anti-adhesion material that can be applied during laparoscopic surgery in comparison with other anti-adhesion materials.

METHODS

Our novel powdered anti-adhesion material is composed of aldehyde dextran and ε-poly(L-lysine). In 40 male rats, a 2.5×2.0-cm abdominal wall resection and cecum abrasion were performed. The rats were randomized into four groups based on the anti-adhesion treatments: normal saline; Seprafilm(®); Interceed(®); and novel powdered anti-adhesion material. The animals were euthanized on days 7 and 28 to evaluate the adhesion severity, area of adhesion formation, gross appearance, and pathological changes.

RESULTS

The adhesion severities on both days 7 and 28 were significantly lower for all anti-adhesion material groups compared with the normal saline group (p<0.05). Pathologically, all groups showed inflammatory cell infiltration on day 7 and complete regeneration of the peritoneum on day 28.

CONCLUSIONS

Our novel powdered anti-adhesion material was found to be effective for reducing postoperative intra-abdominal adhesions and showed equivalent efficacy to commercial anti-adhesion materials.

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.

Adhesion formation to hemostatic agents and its reduction with a sodium hyaluronate/carboxymethylcellulose adhesion barrier

The impact of hemostatic agents on postoperative adhesion formation has not been well studied. We hypothesized that hemostatic agents would be a significant nidus for adhesion formation and that a resorbable barrier would effectively reduce adhesions to hemostatic agents. Four commercial hemostatic agents, each composed of a different biomaterial matrix, were implanted in female Sprague-Dawley rats, and adhesion formation was examined 7 days after surgery. In separate studies, the effects of serosal trauma (via cecal abrasion), added blood, and the presence of chemically modified sodium hyaluronate/carboxymethylcellulose (HA/CMC) barrier on adhesion formation to hemostatic agents were studied. Significant adhesions formed to hemostatic agents even in the absence of traumatized tissue. When applied after cecal abrasion, the incidence of adhesions to the hemostatic agents increased. Addition of blood to this model increased adhesion formation even further, causing adhesions in every animal in the study. An HA/CMC adhesion barrier reduced adhesions to hemostatic agents in the presence of serosal trauma and maintained effectiveness even in the presence of blood. In conclusion, hemostatic agents potentiated adhesion formation at the site of application in a model without trauma. In more challenging models, their adhesiogenic contribution was overwhelmed by trauma and blood. HA/CMC adhesion barrier applied over hemostatic agents at the time of surgery provided significant protection against postoperative adhesions in these preclinical models.

Function of poly (lactic-co-glycolic acid) nanofiber in reduction of adhesion bands

BACKGROUND

In this study, we investigated the anti-adhesive and anti-inflammatory effects of electrospun nanofibrous membranes made of polycaprolactone (PCL), poly-L-lactide (PLLA), poly (lactic-co-glycolic acid) (PLGA), and polyethersulfune (PES) in comparison with the oxidized-regenerated cellulose (Interceed).

MATERIALS AND METHODS

Using an adhesion induction model in mice, the membranes were sutured between the abdominal wall and peritoneum after surgical operation to reveal the best membrane for prevention of postoperative adhesion bands using two scoring adhesion systems.

RESULTS

Compared with other membranes, PLGA, PCL, and Interceed membranes showed a greater ability to reduce adhesions. The lowest level of inflammation in adhesive tissues as well as cell attachment in vitro was detected for PLGA nanofibrous membranes.

CONCLUSIONS

These results suggested that in considering the FDA approved polymers, nanofibrous membranes prepared from PLGA exhibited the highest efficacy for the prevention of postoperative adhesion bands and hold promising potential for application as a new anti-adhesive agent.

A review of the problematic adhesion prophylaxis in gynaecological surgery

Background

Adhesions lead to considerable patient morbidity and are a mounting burden on surgeons and the health care system alike. Although adhesion formation is the most frequent complication in abdominal and pelvic surgery, many surgeons are still not aware of the extent of the problem. To provide the best care for their patients, surgeons should consistently inform themselves of anti-adhesion strategies and include these methods in their daily routine.

Methods

Searches were conducted in PubMed and The Cochrane Library to identify relevant literature.

Findings

Various complications are associated with adhesion formation, including small bowel obstruction, infertility and chronic pelvic pain. Increasingly, an understanding of adhesion formation as a complex process influenced by many different factors has led to various conceivable anti-adhesion strategies. At present, a number of different anti-adhesion agents are available. Although some agents have proved effective in reducing adhesion formation in randomised controlled trials, none of them can completely prevent adhesion formation.

Conclusion

To fulfil our duty to provide best possible care for our patients, it is now time to regard adhesions as the most common complication in surgery. Further research is needed to fully understand adhesion formation and to develop new strategies for adhesion prevention. Large clinical efficacy trials of anti-adhesion agents will make it easier for surgeons to decide which agent to use in daily routine.

Efficacy of polyethylene glycol adhesion barrier after gynecological laparoscopic surgery: Results of a randomized controlled pilot study

Postoperative adhesions are the most frequent complication of peritoneal surgery, causing small bowel obstruction, female infertility and chronic pain. This pilot study assessed the efficacy of a sprayable polyethylene glycol (PEG) barrier in the prevention of de novo adhesions. 16 patients undergoing laparoscopic gynecological surgery were randomly assigned by shuffled sealed envelopes to receive either the adhesion barrier or no adhesion prevention. Incidence and severity of adhesions were scored at eight sites in the pelvis and reassessed by second look laparoscopy. Adhesion prevention was considered successful if no de novo adhesion were found at second look laparoscopy. One patient was excluded before randomization. Nine patients were randomized to treatment and six patients to control group. De novo adhesions were found in 0/9 patients who received the PEG barrier compared to 4/6 without adhesion prevention (0% vs. 67%, P = 0.01). Reduction in adhesion score was significantly greater in patients receiving PEG barrier (−2.6 vs. −0.06, P = 0.03). Meta-analysis of three randomized trials demonstrated that PEG barrier reduces the incidence of adhesions (odds ratio [OR] = 0.27; 95% CI 0.11–0.67). From this study, PEG barrier seems effective in reducing postoperative formation of de novo adhesions.

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.

A prospective, randomised, controlled, double-blind phase I-II clinical trial on the safety of A-Part Gel as adhesion prophylaxis after major abdominal surgery versus non-treated group

Background

Postoperative adhesions occur when fibrous strands of internal scar tissue bind anatomical structures to one another. The most common cause of intra-abdominal adhesions is previous intra-abdominal surgical intervention. Up to 74% of intestinal obstructions are caused by post surgical adhesions. Although a variety of methods and agents have been investigated to prevent post surgical adhesions, the problem of peritoneal adhesions remains largely unsolved. Materials serving as an adhesion barrier are much needed.

Methods/Design

This is a prospective, randomised, controlled, patient blinded and observer blinded, single centre phase I-II trial, which evaluates the safety of A-Part^® Gel as an adhesion prophylaxis after major abdominal wall surgery, in comparison to an untreated control group. 60 patients undergoing an elective median laparotomy without prior abdominal surgery are randomly allocated into two groups of a 1:1- ratio. Safety parameter and primary endpoint of the study is the occurrence of wound healing impairment or peritonitis within 28 (+10) days after surgery. The frequency of anastomotic leakage within 28 days after operation, occurrence of adverse and serious adverse events during hospital stay up to 3 months and the rate of adhesions along the scar within 3 months are defined as secondary endpoints. After hospital discharge the investigator will examine the enrolled patients at 28 (+10) days and 3 months (±14 days) after surgery.

Discussion

This trial aims to assess, whether the intra-peritoneal application of A-Part^® Gel is safe and efficacious in the prevention of post-surgical adhesions after median laparotomy, in comparison to untreated controls.

Trial registration

NCT00646412

Evaluation of a fibrin preparation containing tranexamic acid (Adhexil) in a rabbit uterine horn model of adhesions with and without bleeding and in a model with two surgical loci

OBJECTIVE

To compare the efficacy of a fibrin preparation supplemented with tranexamic acid (Adhexil) with that of established devices, and to determine whether its effect is limited to the site of application.

DESIGN

Rabbit uterine horns were abraded in nonbleeding and bleeding variants of an established adhesions model. In a separate study, a sidewall excision with approximation of the abraded cecum was added. Animals randomly received Adhexil at both, neither, or either loci.

SETTING

Laboratory study.

ANIMAL(S)

Seventy-two female New Zealand White rabbits (Oryctolagus cuniculus).

INTERVENTION(S)

Adhexil, Seprafilm or SprayGel and Interceed.

MAIN OUTCOME MEASURE(S)

The extent of adhesions was evaluated 13 to 16 days after surgery.

RESULT(S)

Adhexil reduced adhesions (15 +/- 7%; 15 +/- 4%) compared with controls (74 +/- 13%; 78 +/- 9%) in the bleeding and nonbleeding models, respectively. The reductions resulting from the use of Seprafilm (39 +/- 17%; 34 +/- 14%) or SprayGel (61 +/- 18%; 43 +/- 14%) (n = 4) were not statistically significant. In the bleeding model, Interceed (48 +/- 15%) reduced adhesions only modestly.

CONCLUSION(S)

In the combined uterine and sidewall model, Adhexil reduced selectively the extent and incidence of adhesions. The absolute and relative performance of Adhexil in an established adhesions model and in the presence of bleeding justifies its further investigation.

Assessment of the Efficacy of the Bio-Absorbable Oxidized Regenerated Cellulose for Prevention of Post-Operative Pericardial Adhesion in the Rabbit Model

Pericardial adhesions complicate re-operative cardiac surgery and several attempts have been made to reduce adhesion formation. The efficacy of bio-absorbable oxidized regenerated cellulose in preventing post-operative pericardial adhesions was evaluated in the present study. Forty New Zealand white rabbits were divided into four groups of 10. In all rabbits an area of pericardium (2 × 2 cm) was excised. The wound was left open in groups 1 and 2 but replaced with bio-absorbable oxidized regenerated cellulose in groups 3 and 4. Rabbits in groups 1 and 3 were killed 3 weeks after surgery and those in groups 2 and 4 were killed at 6 weeks. Groups 1 and 2 showed more severe pericardial adhesions, more fibrous reaction and increased visibility of coronary vessels than groups 3 and 4, although there was no difference in inflammation. Light microscopy showed a mesothelium-like cell layer in groups 3 and 4. It is concluded that bio-absorbable oxidized regenerated cellulose may be suitable in patients receiving staged cardiac surgery and in those with a high probability of re-operation.

The influence of blood on the efficacy of intraperitoneally applied phospholipids for prevention of adhesions

BACKGROUND

The formation of adhesions following abdominal surgery is a well known problem. In previous studies we demonstrated the efficacy and safety of intraperitoneally applied phospholipids in order to prevent adhesion formation. This study evaluates the influence of blood on the efficacy of intraperitoneally applied phospholipids for prevention of adhesions.

METHODS

In 40 Chinchilla rabbits adhesions were induced by median laparotomy, standardized abrasion of the visceral and parietal peritoneum in defined areas of the ventral abdominal wall and the caecum. The animals were randomly divided into four groups. They received either phospholipids 3.0% or normal saline (NaCl 0.9%) (5 ml/kg body weight). In 50% of the rabbits we simulated intraperitoneal bleeding by administration of blood (1.5 ml/kg body weight). The other half served as control group. Ten days following the operation the animals were sacrificed and adhesion formation was assessed by computer aided planimetry and histopathologic examination.

RESULTS

The median adhesion surface area in the NaCl-group (n = 9) amounted to 68.72 mm2, in the NaCl+Blood-group (n = 10) 147.68 mm2. In the Phospholipid (PhL)-group (n = 9) the median adhesion surface area measured 9.35 mm2, in the PhL+Blood-group (n = 9) 11.95 mm2. The phospholipid groups had a significantly smaller adhesion surface area (p < 0.05).

CONCLUSION

Again these results confirm the efficacy of phospholipids in the prevention of adhesions in comparison to NaCl (p = 0.04). We also demonstrated the adhesion preventing effect of phospholipids in the presence of intraperitoneal blood.

Postoperative Pericardial Adhesion Prevention Using Carbylan-SX in a Rabbit Model

INTRODUCTION

The presence of dense adhesions within the pericardial space complicates reoperative cardiac surgery. Prior attempts to reduce adhesion formation after primary cardiac surgery using medications or biomaterials have had variable success. Carbylan-SX (Carbylan Biosurgery Inc., Palo Alto, CA) is a hyaluronan-based biomaterial, which has been shown to be effective at reducing adhesions in a nonthoracic rat model. This study evaluates whether Carbylan-SX can effectively reduce postoperative adhesions within the pericardial cavity.

METHODS

Thirty-eight New Zealand white rabbits underwent a left lateral thoracotomy. A pericardiotomy was made and epicardial adhesions were induced on the anterior surface of the heart using a Dremel device (Racine, WI). The rabbits were divided into four groups: controls with abrasions only receiving no treatment (n=10), Carbylan-SX films (n=10), Carbylan-SX aerosolized hydrogel (n=10), and Seprafilm (n=8). The pericardial sac and chest were subsequently closed. Rabbits were sacrificed at a mean of 15 days. For histological analysis, each heart was divided into 12 separate 1 mm sections. Computer imaging software was used to measure the adhesion thickness and the mean of 12 random measurements for each animal was recorded and statistical analysis performed.

RESULTS

Histological analysis revealed all treatment groups to be significantly better than the control (2159 mum thickness, P<0.0001) at preventing adhesions. The Carbylan-SX film and Carbylan-SX aerosolized hydrogel both proved to be better at preventing adhesions than Seprafilm (Genzyme Corp., Cambridge, MA) with an average adhesion thickness of 454 and 577 microm, respectively, compared with 1319 microm for Seprafilm (P<0.0001 and P<0.0005, respectively). The Carbylan-SX film and Carbylan-SX aerosolized hydrogel were equally effective at preventing adhesion formation.

CONCLUSION

Carbylan-SX film and Carbylan-SX aerosolized crosslinkable hydrogel are equally effective methods of reducing postoperative pericardial adhesions within the pericardial cavity. Both the Carbylan-SX film and aerosolized hydrogel showed a significantly greater reduction in adhesions than Seprafilm. Clinical application of Carbylan-SX could have significant therapeutic implications in the future.

Intérêt des produits antiadhérentiels en chirurgie gynécologique

Adhesion barriers are intraperitoneal agents, solid or fluid, developed in order to prevent postoperative adhesions. In this article, we evaluate the efficiency of these new barrier agents for adhesion prevention in gynaecologic surgery, undertaking a review of controlled clinical trials published. Several human clinical trials demonstrated the safety and efficiency of both Interceed and Seprafilm. As far as other barrier agents are concerned, data are still insufficient to recommend them for clinical use. There is a need for other randomised controlled trials in order to evaluate functional efficiency of anti adhesion agents.

Reduced postoperative intra-abdominal adhesions using Carbylan-SX, a semisynthetic glycosaminoglycan hydrogel

OBJECTIVE

To compare the efficacy of crosslinked Carbylan-SX (Carbylan BioSurgery, Inc., Palo Alto, CA) hydrogel films and sprayable gels as physical barriers in reducing postoperative intra-abdominal adhesions in the rat cecum-abdominal wall and rat uterine horn models.

DESIGN

Pre-formed crosslinked Carbylan-SX films and sprayable in situ crosslinkable Carbylan-SX gels were evaluated in rat cecum-abdominal wall and rat uterine horn models and compared with commercially available and clinically used Seprafilm.

SETTING

University animal research facility.

ANIMALS

Female Wistar rats.

INTERVENTION(S)

Abrasions were made with the foot-pedal-operated Flex-shaft (Dremel, Racine, WI) on both the cecum and abdominal wall (each area 10 mm in diameter) in female rats as one model and on both uterine horns (3 x 10 mm) in female rats as the other model. In each of the two adhesion models, four groups were assigned with eight rats in each group: (1) untreated control, (2) treated with Seprafilm (Genzyme Corporation, Cambridge, MA), (3) treated with preformed Carbylan-SX hydrogel films, and (4) treated with sprayable Carbylan-SX gel.

MAIN OUTCOME MEASURE(S)

Extent and severity of postoperative adhesions between the cecum and the abdominal wall in rat cecum-abdominal wall model and between the uterine horns in rat uterine horn model.

RESULT(S)

The Carbylan-SX film and the Carbylan-SX sprayable gel led to fewer adhesions than Seprafilm in both rat adhesion models. Interestingly, a single physical form was not optimal for both models: the Carbylan film was more efficacious in the rat uterine horn model, whereas Carbylan gel gave the best results in the rat cecum-abdominal wall model.

CONCLUSION(S)

Both Carbylan-SX film and gel were efficacious in reducing postoperative intra-abdominal adhesion formation in rat cecum-abdominal wall and uterine horn models.

In vivo performance of antibiotic embedded electrospun PCL membranes for prevention of abdominal adhesions

The aim of this study was to prepare nonwoven materials from poly(epsilon-caprolactone) (PCL) and their antibiotic containing forms by electrospinning, so as to prevent postsurgery induced abdominal adhesions in rats. epsilon-Caprolactone was first polymerized by ring-opening polymerization, and then it was processed into matrices composed of nanofibers by electrospinning. A model antibiotic (Biteral) was embedded within a group of PCL membranes. In the rat model, defects on the abdominal walls in the peritoneum were made to induce adhesion. The plain or antibiotic embedded PCL membranes were implanted on the right side of the abdominal wall. No membrane implantation was made on the left side of the abdominal wall that served as control. Macroscopical and histological evaluations showed that using these barriers reduces the extent, type, and tenacity of adhesion. The antibiotic embedded membranes significantly eliminated postsurgery abdominal adhesions, and also improved healing.

Prospective Evaluation of Adhesion Formation and Shrinkage of Intra-Abdominal Prosthetics in a Rabbit Model

Laparoscopic ventral hernia repair requires an intraperitoneal prosthetic; however, these materials are not without consequences. We evaluated host reaction to intraperitoneal placement of various prosthetics and the functional outcomes in an animal model. Mesh (n = 15 per mesh type) was implanted on intact peritoneum in New Zealand white rabbits. The mesh types included ePTFE (DualMesh®), ePTFE and polypropylene (Composix®), polypropylene and oxidized regenerated cellulose (Proceed®), and polypropylene (Marlex®). Adhesion formation was evaluated at 1, 4, 8, and 16 weeks using 2-mm mini-laparoscopy. Adhesion area, adhesion tenacity, prosthetic shrinkage, and compliance were evaluated after mesh explantation at 16 weeks. DualMesh® had significantly less adhesions than Proceed®, Composix®, or Marlex® at 1, 4, 8, and 16 weeks ( P < 0.0001). Marlex® had significantly more adhesions than other meshes at each time point ( P < 0.0001). There were no statistically significant differences in adhesions between Proceed® and Composix® meshes. After mesh explantation, the mean area of adhesions for Proceed® (4.6%) was less than for Marlex® (21.7%; P = 0.001). The adhesions to Marlex® were statistically more tenacious than the DualMesh® and Composix® groups. Overall prosthetic shrinkage was statistically greater for DualMesh® (34.7%) than for the remaining mesh types ( P < 0.01). Mesh compliance was similar between the groups. Prosthetic materials demonstrate a wide variety of characteristics when placed inside the abdomen. Marlex® formed more adhesions with greater tenacity than the other mesh types. DualMesh® resulted in minimal adhesions, but it shrank more than the other mesh types. Each prosthetic generates a varied host reaction. Better understanding of these reactions can allow a suitable prosthetic to be chosen for a given patient in clinical practice.

Use of icodextrin 4% solution in the prevention of adhesion formation following general surgery: from the multicentre ARIEL Registry

INTRODUCTION

Intra-abdominal adhesions occur in many patients following major abdominal surgery and represent a serious burden to patients and healthcare providers. The multicentre ARIEL (Adept Registry for Clinical Evaluation) Registry was established to gather clinical experiences in the use of icodextrin 4% solution, an approved adhesion-reduction agent, during routine general surgery.

PATIENTS AND METHODS

General surgeons from five European countries completed anonymised data collection forms for patients undergoing laparotomy or laparoscopy. Surgeons recorded patient demographics, use of icodextrin 4% solution and adverse events, and made subjective assessments of ease of use and patient acceptability with the agent.

RESULTS

The general surgery registry included 1738 patients (1469 laparotomies, 269 laparoscopies). Leakage of fluid from the surgical site did not appear to be affected by icodextrin 4% solution and was classified as 'normal' or 'less than normal' in most patients (laparotomies 86%, laparoscopies 88%). Overall, satisfaction with ease of use was rated as 'good' or 'excellent' by the majority of surgeons (laparotomies 77%, laparoscopies 86%). Patient acceptability was also good, with ratings of 'as expected' or 'less than expected' in most cases for both abdominal distension (laparotomies 90%, laparoscopies 91%) and abdominal discomfort (laparotomies 91%, laparoscopies 93%). Adverse events occurred in 30.6% of laparotomy patients and 16.7% of laparoscopy patients; the most common events were septic/infective events (4.2% and 3.4% in the laparotomy and laparoscopy groups, respectively). Anastomotic wound-healing problems were reported in 7.6% of patients in the subset of laparoscopy patients undergoing anastomotic procedures (n = 66).

DISCUSSION

Volumes of icodextrin 4% solution used as an irrigant and instillate were in line with recommendations. Surgeons considered the agent to be easy to use and acceptable to patients. The reported frequencies of adverse events were in line with those published in the literature for surgical procedures, supporting the good safety profile of this agent.

CONCLUSIONS

Icodextrin 4% solution can be used in a wide range of surgical procedures. In combination with good surgical technique, it may play an important role in adhesion reduction.

Experimental study evaluating the effect of a barrier method on postoperative intraabdominal adhesions

The purpose of this animal study was to determine if tissue glue-coated collagen sponge is an effective barrier method to prevent localized adhesions in a modified rabbit sidewall model. Rabbits were divided into two groups and underwent laparotomy with subsequent creation of a cecal wound according to the rabbit sidewall model. Rabbits of group I (treatment group; n = 10) were treated with a TachoComb H patch placed on the defect, whereas group II animals (control group; n = 6) did not receive further treatment. All animals were sacrificed 2 weeks postoperatively and adhesions were evaluated using special adhesion score. A further six rabbits underwent TachoComb H application at the cecum to investigate the histological changes during a course of 12 weeks. The average adhesion scores were significantly (P < 0.05) reduced in the treatment group compared to the controls. Histologically the TachoComb H patch was surrounded by granulation tissue without signs of infection. Tissue glue-coated collagen sponge (TachoComb H) is effective to prevent localized intraabdominal adhesions in the modified rabbit sidewall model.

The effect of seprafilm and interceed on capsule formation around silicone discs in a rat model

The insertion of a foreign substance, such as a breast implant into mammalian soft tissues, evokes a wound healing response that culminates in a dense connective-tissue envelope or capsule surrounding the implant. Several biodegradable products, such as Seprafilm (carboxymethylcellulose and hyaluronic acid) and Interceed (oxidized regenerated cellulose), have been demonstrated to inhibit adhesions in abdominal and gynecologic surgery. The ability of these cellulose compounds to inhibit capsule formation was addressed in this investigation. Twenty-eight rats were implanted intermuscularly with either plain silicone discs (10 animals), discs wrapped in Seprafilm (10 animals), or discs covered with Interceed (8 animals). Additional control animals (6 animals) consisted of two that had sham operations, two animals implanted with Seprafilm only, and two more implanted with Interceed only. Animals were sacrificed in pairs at varying time intervals after implantation (2, 4, 8, 12, and 16 wk), and the tissues around the silicone discs were analyzed with light microscopy. Control animals were sacrificed at 8 wk. Both Interceed and Seprafilm slowed the formation of a capsule around the implanted silicone discs as both products were degraded. Evidence of residual material, presumably Seprafilm and Interceed, was seen intracellularly in animals 3 to 4 mo, respectively, after implantation. However, neither material prevented the eventual formation of a fibrous capsule around the silicone discs. The results of this study suggest that encapsulating foreign substances with these types of biodegradable materials will not significantly hinder capsule formation. A more direct attack on the wound healing mechanism may provide a definitive solution for capsule problems with implanted materials.

Prevention of postsurgery-induced abdominal adhesions by electrospun bioabsorbable nanofibrous poly(lactide-co-glycolide)-based membranes

OBJECTIVES

The objective of this study was to evaluate the efficacy of nonwoven bioabsorbable nanofibrous membranes of poly(lactideco-glycolide) for prevention of postsurgery-induced abdominal adhesions.

SUMMARY BACKGROUND DATA

Recent reports indicated that current materials used for adhesion prevention have only limited success. Studies on other bioabsorbable materials using a new fabrication technique demonstrated the promising potential of generating an improved and inexpensive product that is suitable for a variety of surgical applications.

METHODS

All rats underwent a midline celiotomy. The cecum was identified and scored using an abrasive pad until serosal bleeding was noted on the anterior surface. A 1 x 1 cm of abdominal wall muscle was excised directly over the cecal wound. The celiotomy was then closed in 2 layers immediately (control) after a barrier was laid in between the cecum and the abdominal wall. All rats underwent a second celiotomy after 28 days to evaluate the extent of abdominal adhesions qualitatively and quantitatively.

RESULTS

Cecal adhesions were reduced from 78% in the control group to 50% in the group using biodegradable poly(lactide-co-glycolide) (PLGA) nonwoven nanofibrous membranes (n = 10, P = 0.2) and to 22% in the group using membranes containing PLGA and poly(ethylene glycol)/poly(D,L-lactide) (PEG-PLA) blends (n = 9, P = 0.03). Electrospinning method also enabled us to load an antibiotic drug Cefoxitin sodium (Mefoxin; Merck Inc., West Point, PA) with high efficacy. The electrospun PLGA/PEG-PLA membranes impregnated with 5 wt% cefoxitin sodium, which amounts to approximately 10% of the systemic daily dose typically taken after surgery in humans, completely prevented cecal adhesions (0%) in rats.

CONCLUSIONS

Electrospun nonwoven bioabsorbable nanofibrous membranes of poly(lactide-co-glycolide) were effective to reduce adhesions at the site of injury using an objective rat model. The membrane acted as a physical barrier but with drug-delivery capability. The combined advantages of composition adjustment, drug-loading capability, and easy placement handling (relatively hydrophobic) make these membranes potentially successful candidates for further clinical evaluations.

A randomized, prospective, controlled, multicenter clinical trial of a sprayable, site-specific adhesion barrier system in patients undergoing myomectomy

OBJECTIVE

To assess the safety and effectiveness of a sprayable, site-specific adhesion barrier system (SprayGel; Confluent Surgical, Waltham, MA) for reduction of adhesion formation.

DESIGN

Prospective, randomized, controlled phase III trial.

SETTING

University clinic (Kiel, Germany) and private clinic (Bordeaux, France).

PATIENT(S)

Sixty-six women aged 34.9 years (range, 23-52 years) undergoing laparoscopic or open uterine myomectomy, enrolled over a 15-month period.

INTERVENTION(S)

Patients were randomized to receive either optimal surgical treatment plus adhesion barrier or optimal surgical treatment alone, followed by second-look laparoscopy.

MAIN OUTCOME MEASURE(S)

Initial and second-look laparoscopy procedures were assessed for incidence, extent, and severity of adhesions; all patients were followed for safety analysis.

RESULT(S)

When compared with initial surgery, the mean adhesion tenacity score of adhesions seen at second-look laparoscopy was significantly reduced in treatment patients compared with control patients (0.6 vs. 1.7, a 64.7% reduction). Mean adhesion extent score at second-look laparoscopy compared with initial surgery was 4.5 cm(2) vs. 7.2 cm(2), mean adhesion incidence score was 0.64 vs. 1.22. Of 64 patients, 40 (62.5%) returned for second-look laparoscopy.

CONCLUSION(S)

This adhesion barrier was safe, well tolerated, and demonstrated efficacy in a population of patients known to be at risk for adhesion formation. There were no adverse effects attributable to the product and no patients in whom it could not be applied.

Preoperative leuprolide acetate combined with Interceed optimally reduces uterine adhesions and fibrosis in a rabbit model,

OBJECTIVE

To determine the optimal approach to prevent adhesions comparing leuprolide acetate (GnRH-a), Interceed (oxidized regenerated cellulose; Johnson & Johnson Medical, Inc., New Brunswick, NJ), and a combination of leuprolide with Interceed in a rabbit uterine horn adhesion model.

DESIGN

Prospective, randomized, blinded study.

SETTING

Certified animal care facility.

ANIMAL(S)

Twenty-eight sexually mature, female New Zealand White rabbits.

INTERVENTION(S)

Animals were prospectively randomized (by number generator) to receive GnRH-a or saline. After 6 weeks, standard surgical manipulations were performed at three sites in each uterine horn by [1]. suture, [2]. unipolar cautery, and [3]. superficial abrasion. Interceed was applied over one randomly assigned uterine horn only. Six weeks after surgery, uterine adhesions were assessed visually, and tissue fibrosis was assessed by histology.

MAIN OUTCOME MEASURE(S)

Presence or absence of adhesions and microscopic tissue fibrosis.

RESULT(S)

Gonadotropin-releasing hormone agonist significantly decreased adhesions, whereas Interceed alone did not reduce adhesions. However, GnRH agonist plus Interceed was the most effective measure to reduce tissue fibrosis.

CONCLUSION(S)

Preoperative GnRH-a is more effective than Interceed in preventing surgical adhesions in the rabbit uterine horn. However, preoperative GnRH-a plus Interceed may provide optimal results in this animal model, because microscopic tissue fibrosis is minimized with this combination.