Comparative effectiveness of several agents for preventing postoperative adhesions

Adhesion barriers in gynecologic surgeries and cesarean section: An Asia-Pacific expert panel consensus recommendation

Adhesions arising from gynecologic surgeries and cesarean sections pose substantial clinical, social, and economic challenges, leading to issues like pelvic pain, infertility, bowel obstruction, and recurring surgeries. Preventing adhesions is a pressing unmet need, hindered by difficulties in assessing postoperative adhesions and understanding barriers. To bridge adhesion prevention gaps, statements on clinical practices were synthesized to present Asia-Pacific expert perspectives on gynecologic surgery and cesarean section adhesion prevention. An expert panel of eight physicians from various healthcare settings in the Asia-Pacific region was convened and a comprehensive literature search on topics related to adhesion prevention in gynecologic surgeries and cesarean sections was performed. Information from full-text publications was used to develop draft consensus statements, with each statement assigned the highest available evidence level based on a systematic literature review and graded using the Oxford Center for Evidence-based Medicine criteria. A modified Delphi process, involving two rounds of online voting and discussions with an extended group of 109 experts, was employed to reach a consensus on six topics related to adhesion barriers. A set of 15 consensus statements were synthesized. Key topics include adhesion incidence in Asia, cesarean section complications, barrier application status, adhesion formation and prevention, absorbable barriers' effectiveness, recommendations, and future considerations. The statements provide guidance for healthcare professionals, especially in the Asia-Pacific region, to tackle the challenges posed by postoperative adhesions and improve patient outcomes. Further research is needed to enhance understanding and prevention of adhesions in this region.

Peritoneal Adhesions and their Prevention - Current Trends

The development of adhesions after gynecologic surgery is a severe problem with ramifications that go beyond the medical complications patients suffer (which most often include pain, obstruction and infertility), since they also impose a huge financial burden on the health care system and increase the workload of surgeons and all personnel involved in surgical follow-up care. Surgical techniques to avoid adhesion formation have not proven to be sufficient and pharmaceutical approaches for their prevention are even less effective, which means that the use of adhesion prevention devices is essential for achieving decent prophylaxis. This review explores the wide range of adhesion prevention products currently available on the market. Particular emphasis is put on prospective randomized controlled clinical trials that include second-look interventions, as these offer the most solid evidence of efficacy. We focused on adhesion scores, which are the most common way to quantify adhesion formation. This enables a direct comparison of the efficacies of different devices. While the greatest amount of data are available for oxidized regenerated cellulose, the outcomes with this adhesion barrier are mediocre and several studies have shown little efficacy. The best results have been achieved using adhesion barriers based on either modified starch, i.e., 4DryField® PH (PlantTec Medical GmbH, Lüneburg, Germany), or expanded polytetrafluoroethylene, i.e., GoreTex (W.L. Gore & Associates, Inc., Medical Products Division, Flagstaff, AZ), albeit the latter, as a non-resorbable barrier, has a huge disadvantage of having to be surgically removed again. Therefore, 4DryField® PH currently appears to be a promising approach and further studies are recommended.

Recombinant human lubricin for prevention of postoperative intra-abdominal adhesions in a rat model

BACKGROUND

Postoperative intra-abdominal adhesions are a major cause of morbidity and mortality and contribute to a heavy burden on health care resources. At present, numerous introduced adhesion prevention products have demonstrated some benefit but none are consistently effective. The aim of this study was to examine the effectiveness of recombinant human lubricin in preventing intra-abdominal adhesion formation.

MATERIALS AND METHODS

A total of 62 male Wistar Albino rats were randomly assigned to the study. Six rats were used to the initial pilot study and 56 rats were randomized into four groups: (1) control cecal abrasion; (2) treatment cecal abrasion with 0.5 mg/mL lubricin solution; (3) control cecal enterotomy and primary closure; and (4) treatment cecal enterotomy and primary closure with 0.5 mg/mL lubricin solution. Rats were sacrificed at 3 d and 21 d postoperatively for the pilot and main studies, respectively. Macroscopic and microscopic adhesion severity was graded by blinded investigators.

RESULTS

For the pilot study, all six rats successfully reached the end point indicating safety of the lubricin gel. In the main randomized study, adhesions in the treated cecal abrasion group were significantly reduced both macroscopically (P = 0.001) and microscopically (fibrosis P = 0.009, inflammation P < 0.0001), when compared with the control group. In the cecal enterotomy group, adhesions were reduced for the treatment group in macroscopic (P = 0.011) and microscopic grading (fibrosis P = 0.500, inflammation P = 0.206) compared with the control group.

CONCLUSIONS

Recombinant human lubricin significantly reduced both macroscopic and microscopic intra-abdominal adhesions in the cecal abrasion group. The cecal enterotomy group showed modest macroscopic adhesion reduction. Future study using higher concentration of lubricin solution are needed to investigate its toxicity and more profound antiadhesion properties in significant operations.

Chronic safety assessment of hemostatic self-expanding foam: 90-day survival study and intramuscular biocompatibility

BACKGROUND

Noncompressible hemorrhage is a significant cause of preventable death in trauma, with no effective presurgical treatments. We previously described the efficacy and 28-day safety of a self-expanding hemostatic foam in swine models. We hypothesized that the 28-day results would be confirmed at a second site and that results would be consistent over 90 days. Finally, we hypothesized that the foam material would be biocompatible following intramuscular implantation.

METHODS

Foam treatment was administered in swine following a closed-cavity splenic injury. The material was explanted after 3 hours, and the animals were monitored to 28 days (n = 6) or 90 days (n = 4). Results were compared with a control group with injury alone (n = 6 at 28 days, n = 3 at 90 days). In a separate study, foam samples were implanted in rabbit paravertebral muscle and assessed at 28 days and 90 days relative to a Food and Drug Administration-approved polyurethane mesh (n = 3 per group).

RESULTS

All animals survived the acute phase of the study, and the foam animals required enterorrhaphy. One animal developed postoperative ileus and was euthanized; all other animals survived to the 28-day or 90-day end point without clinically significant complications. Histologic evaluation demonstrated that remnant particles were associated with a fibrotic capsule and mild inflammation. The foam was considered biocompatible in 28-day and 90-day intramuscular implant studies.

CONCLUSION

Foam treatment was not associated with significant evidence of end-organ dysfunction or toxicity at 28 days or 90 days. Remnant foam particles were well tolerated. These results support the long-term safety of this intervention for severely bleeding patients.

Pirfenidone vs. sodium hyaluronate/carboxymethylcellulose as prevention of the formation of intra-abdominal adhesions after colonic surgery. A randomized study in an experimental model

INTRODUCTION

Up to 93% of patients undergoing abdominal surgery will develop intra-abdominal adhesions with the subsequent morbidity that they represent. Various substances have been tested for the prevention of adhesions with controversial results; the aim of our study is to compare the capability of pirfenidone in adhesion prevention against sodium hyaluronate/carboxymethylcellulose.

METHODS

A randomized, prospective, longitudinal experimental study with Winstar rats. They were divided into 3 groups. The subjects underwent an exploratory laparotomy and they had a 4cm(2) cecal abrasion. The first group received saline on the cecal abrasion, and groups 2 and 3 received pirfenidone and sodium hyaluronate/carboxymethylcellulose respectively. All rats were sacrificed on the 21st day after surgery and the presence of adhesions was evaluated with the modified Granat scale. Simple frequency, central tendency and dispersion measures were recorded. For the statistical analysis we used Fisher's test.

RESULTS

To evaluate adhesions we used the Granat's modified scale. The control group had a median adhesion formation of 3 (range 0-4). The pirfenidone group had 1.5 (range 0-3), and the sodium hyaluronate/carboxymethylcellulose group had 0 (range 0-1). There was a statistically significant difference to favor sodium hyaluronate/carboxymethylcellulose against saline and pirfenidone (P<0.009 and P<.022 respectively).

CONCLUSIONS

The use of sodium hyaluronate/carboxymethylcellulose is effective for the prevention of intra-abdominal adhesions. More experimental studies are needed in search for the optimal adhesion prevention drug.

Mesothelial cells in tissue repair and fibrosis

Mesothelial cells are fundamental to the maintenance of serosal integrity and homeostasis and play a critical role in normal serosal repair following injury. However, when normal repair mechanisms breakdown, mesothelial cells take on a profibrotic role, secreting inflammatory, and profibrotic mediators, differentiating and migrating into the injured tissues where they contribute to fibrogenesis. The development of new molecular and cell tracking techniques has made it possible to examine the origin of fibrotic cells within damaged tissues and to elucidate the roles they play in inflammation and fibrosis. In addition to secreting proinflammatory mediators and contributing to both coagulation and fibrinolysis, mesothelial cells undergo mesothelial-to-mesenchymal transition, a process analogous to epithelial-to-mesenchymal transition, and become fibrogenic cells. Fibrogenic mesothelial cells have now been identified in tissues where they have not previously been thought to occur, such as within the parenchyma of the fibrotic lung. These findings show a direct role for mesothelial cells in fibrogenesis and open therapeutic strategies to prevent or reverse the fibrotic process.

Preventing intraperitoneal adhesions with linezolid and hyaluronic acid/carboxymethylcellulose: a comparative study in cecal abrasion model

BACKGROUND

We aimed to compare the effectiveness of linezolid in preventing intraperitoneal adhesions with hyaluronic acid + carboxymethylcellulose (Seprafilm).

METHODS

Thirty rats were divided randomly into 3 groups: Group I (control), untreated; Group II (Seprafilm); and Group III (linezolid). All rats were sacrificed on the 14th day after surgery. Macroscopic adhesion, inflammation, and fibrosis were evaluated.

RESULTS

The multiple comparisons between groups showed a statistically significant difference for adhesion. There were statistically significant differences between Group I and II and I and III, but no statistically significant difference between Group II and III. The multiple comparisons between the groups showed a statistically significant difference for inflammation and fibrosis. For inflammation and fibrosis, there was a statistically significant difference between Group I and II and I and III, but no statistically significant difference between Group II and III.

CONCLUSION

The efficiency of linezolid in reducing the formation of intraperitoneal adhesions was statistically significant compared with the control group.

Peritoneal response to abdominal surgery: the role of equine abdominal adhesions and current prophylactic strategies

Intra-abdominal adhesions constitute a significant clinical and surgical problem that can lead to complications such as pain and bowel occlusion or subocclusion. These adhesions are frustrating and potentially fatal, representing a major postoperative complication in abdominal surgery. It is estimated that 32% of horses undergoing laparotomy will present clinical symptoms due to adhesions, but the true prevalence is not known because a large proportion of animals with postoperative recurrent colics are medically treated or submitted to euthanasia without necropsy. Adhesions are highly cellular, vascularized, dynamic structures that are influenced by complex signaling mechanisms. Understanding their pathogenesis could assist in applying better therapeutic strategies and in developing more effective antiadhesion products. Currently, there are no definitive strategies that prevent adhesion formation, and it is difficult to interpret the results of existing studies due to nonstandardization of an induction model and evaluation of their severity. The best clinical results have been obtained from using minimally traumatic surgical techniques, anti-inflammatory agents, antimicrobials, anticoagulants, and mechanical separation of serosal surfaces by viscous intraperitoneal solutions or physical barriers. This paper aims to review adhesion formation pathogenesis, guide the understanding of major products and drugs used to inhibit adhesion formation, and address their effectiveness in the equine species.

The effect of montelukast and antiadhesion barrier solution on the capsule formation after insertion of silicone implants in a white rat model

BACKGROUND AND PURPOSES

Capsular contracture is one of the most severe complications that can occur in breast surgery following silicone implant insertion. The purpose of this study was to investigate the effect of montelukast and antiadhesion barrier solution (AABS) on reducing capsular formation and their possible synergism.

MATERIALS AND METHODS

This study was approved by the Animal Ethics Committee (Reference No. KNU 2012-33) and was conducted in accordance with the Kyungpook National University - Institutional Animal Care and Use Committee, Animal Ethics Committee. The experiments in this study were conducted in vivo in 4 groups of 24 rats. Following silicone implant insertion, the pocket was injected with different agents. Group I (control group) was given normal saline injections into the pocket and fed with pure water. Group II was given injections of AABS and fed with pure water. Group III was given injections of normal saline and the medication montelukast during the experimental period. Group IV was given injections of AABS and montelukast as postoperative medication. Peri-implant capsules were excised after 8 weeks and were evaluated for transparency, inflammatory cell content, capsule thickness, collagen pattern and TGF-β expression.

RESULTS

The capsules in the experimental groups (i.e., groups II-IV) were significantly more transparent than those in group I (controls; p < 0.05, Student's t test). The mean capsule thickness of the experimental groups II (296 ± 14.76 μm), III (280 ± 14.77 μm) and IV (276 ± 39.28 μm) was smaller than that of the control group I (361 ± 35.43 μm). Compared to the control group, the histologic findings in the experimental groups suggested a decreased inflammatory response occurring in the peri-implant capsules as they exhibited minor vascularization and a reduced number of mast cells and macrophages. The collagen patterns in the experimental groups were of a lower density than in the control group with the former showing a loose, tidy collagen pattern. The amounts of TGF-β and collagen I were higher in the control group than in the experimental groups. Group IV (the synergic effect group) had a more pronounced effect on all the parameters examined than that in groups II and III with separate drug administration.

CONCLUSIONS

Montelukast and AABS reduced the thickness, the inflammatory cell infiltrate and the myofibroblast content of the peri-implant capsules around silicone implants in this white rat model. They lowered the expression of the fibrotic mediator, TGF-β, and inhibited the peri-implant capsular fibrosis. Therefore, montelukast and AABS are effective in the reduction of silicone-induced peri-implant capsular formation.

Influence of the carboxymethyl chitosan anti-adhesion solution on the TGF-β1 in a postoperative peritoneal adhesion rat

The aim of this paper was to investigate the effect of carboxymethyl chitosan anti-adhesion solution on prevention of postsurgical adhesion. Forty adult male Wistar rats were randomly divided into three groups: 0.9% normal saline solution (group A), hyaluronic acid gels (group B) and carboxymethyl chitosan anti-adhesion solution (group C). The animals were treated with normal saline, hyaluronic acid gels or carboxymethyl chitosan anti-adhesion solution at the time of surgery. After 2 or 3 weeks, the degree of adhesions and histological effects were determined. The adhesions in groups B and C were significantly decreased, and the levels of TGF-β1 and hydroxyproline in group C were significantly lower than that in group A (P < 0.05). The histopathology in group C showed fewer inflammatory cells and fibroblasts. Carboxymethyl chitosan anti-adhesion solution can effectively prevent postoperative adhesion which is a promising drug delivery system in the context of postsurgical anti-adhesion.

Antiadhesive effect and safety of sodium hyaluronate-carboxymethyl cellulose membrane in thyroid surgery

Purpose

A number of researchers have suggested the use of sodium hyaluronate carboxymethyl cellulose (HA-CMC) membrane for preventing postoperative adhesion. This study evaluated the antiadhesive effect and safety of HA-CMC membrane in thyroidectomy for papillary thyroid cancer.

Methods

One hundred sixty-two patients who underwent thyroidectomy were prospectively randomized. In the study group of 80 patients, the 7.5 cm × 13 cm HA-CMC membrane was applied to the operative field after thyroidectomy. The subjects were asked about complications including adhesive symptoms using an 8-item questionnaire at 2 weeks, 3 months, and 6 months after surgery. In addition, items on the appearance of neck wrinkles and scars were evaluated by a physician who had no information about the patient's allocation.

Results

There were no significant differences in complications such as swallowing difficulty, and wrinkles between study and control groups. Both groups presented significantly decreased scores over time in swallowing difficulty, and wrinkles. There were no complications regarding the HA-CMC membrane.

Conclusion

The antiadhesive effect of HA-CMC membrane in thyroid surgery is still uncertain, although it is biologically safe. Further investigation is needed to confirm the antiadhesive effect of HA-CMC membrane in thyroid surgery.

Influence of 4% icodextrin solution on peritoneal tissue response and adhesion formation

BACKGROUND

Postoperative peritoneal adhesion formation following abdominal surgery remains a relevant surgical problem. The application of soluble physico-chemical barriers like 4% icodextrin is one approach to protect the peritoneal surface from getting linked to adhesive scar. The aim of this study was to investigate the influence of 4% icodextrin on peritoneal tissue response both of visceral and parietal peritoneum, adhesion formation and wound healing.

METHODS

40 rats were divided into two groups. After creation of an intraabdominal defect, either 4% icodextrin (Adept®) or sodium chloride was applied. Animals were sacrificed after 7 and 21 days. Adhesions were scored by an adhesion score. Furthermore, immunohistochemical investigations were conducted to determine the discrete influence of icodextrin on the parietal and visceral peritoneal tissue responses (CD68+ macrophages, CD3+ T-lymphocytes, vimentin for mesenchymal cells, HBME-1 for mesothelial cells, and as components of wound healing COX-2, C-myc, catenin).

RESULTS

Postoperative peritoneal adhesions were predominantly present in the sodium chloride group as compared to the icodextrin group (14/19 (74%) vs. 9/19 (47%); p = 0.048). The adhesion score however did not reveal any significant differences, (p = 0.614). Furthermore, the expression of vimentin in both the parietal and visceral peritoneum after 21 days was significantly lower in the icodextrin group than in the sodium chloride group (p = 0.038 and p = 0.028, respectively). No significant differences were observed for macrophages, lymphocytes, reperitonealisation or the expression of COX-2, C-myc or Catenin.

CONCLUSIONS

The intraperitoneal application of 4% icodextrin reduces adhesion formation in comparison to sodium chloride. 4% icodextrin solution reduces the inflammatory and mesenchymal infiltrate in the wounded area, thus improving the ratio of mesothel cells to mesenchymal infiltrate. As demonstrated, icodextrin is able to ameliorate the local tissue response. Further experimental studies would be done to elaborate the impact on the early response of the adaptive immune system, which may then trigger the subsequent wound healing and tissue repair.

Peritoneal adhesion index (PAI): proposal of a score for the "ignored iceberg" of medicine and surgery

Peritoneal adhesions describe a condition in which pathological bonds form between the omentum, the small and large bowels, the abdominal wall, and other intra-abdominal organs. Different classification systems have been proposed, but they do not resolve the underlying problem of ambiguity in the quantification and definition of adhesions. We therefore propose a standardized classification system of adhesions to universalize their definition based on the macroscopic appearance of adhesions and their diffusion to different regions of the abdomen. By scoring with these criteria, the peritoneal adhesion index (PAI) can range from 0 to 30, unambiguously specifying precise adhesion scenarios. The standardized classification and quantification of adhesions would enable different studies to more meaningfully integrate their results, thereby facilitating a more comprehensive approach to the treatment and management of this pathology.

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.

Visceral mobilization can lyse and prevent peritoneal adhesions in a rat model

OBJECTIVE

Peritoneal adhesions are almost ubiquitous following surgery. Peritoneal adhesions can lead to bowel obstruction, digestive problems, infertility, and pain, resulting in many hospital readmissions. Many approaches have been used to prevent or treat adhesions, but none offer reliable results. A method that consistently prevented or treated adhesions would benefit many patients. We hypothesized that an anatomically-based visceral mobilization, designed to promote normal mobility of the abdominal contents, could manually lyse and prevent surgically-induced adhesions.

MATERIAL AND METHODS

Cecal and abdominal wall abrasion was used to induce adhesions in 3 groups of 10 rats (Control, Lysis, and Preventive). All rats were evaluated 7 days following surgery. On postoperative day 7, unsedated rats in the Lysis group were treated using visceral mobilization, consisting of digital palpation, efforts to manually lyse restrictions, and mobilization of their abdominal walls and viscera. This was followed by immediate post-mortem adhesion evaluation. The rats in the Preventive group were treated daily in a similar fashion, starting the day after surgery. Adhesions in the Control rats were evaluated 7 days after surgery without any visceral mobilization.

RESULTS

The therapist could palpate adhesions between the cecum and other viscera or the abdominal wall. Adhesion severity and number of adhesions were significantly lower in the Preventive group compared to other groups. In the Lysis and Preventive groups there were clear signs of disrupted adhesions.

CONCLUSIONS

These initial observations support visceral mobilization may have a role in the prevention and treatment of post-operative adhesions.

Preventing intraperitoneal adhesions with atorvastatin and sodium hyaluronate/carboxymethylcellulose: a comparative study in rats

OBJECTIVES

The aim of this study was to compare the effectiveness of atorvastatin with the sodium hyaluronate/carboxymethylcellulose (HA/CMC, Seprafilm; Genzyme; Genzyme Biosurgery Corporation, Cambridge, MA) in preventing postoperative intraperitoneal adhesion formation in rats.

METHODS

Sixty Wistar rats underwent a laparotomy, and adhesions A were induced by cecal abrasion. The animals were divided into 4 groups: group 1, control A; group 2, (A + atorvastatin); group 3, (A + HA/CMC), and group 4, (A + atorvastatin + HA/CMC). The atorvastatin (groups 2 and 4) and HA/CMC (groups 3 and 4) were administered intraperitoneally before the abdominal wall was closed. After 14 days, adhesions were classified by 2 independent surgeons.

RESULTS

The adhesion scores (mean +/- standard deviation) for groups 1, 2, 3, and 4 were 2.93 +/- .59, 1.85 +/- 1.07, 1.80 +/- .86, and 1.93 +/- .70, respectively. The differences in adhesion scores among all 3 preventive groups (groups 2, 3, and 4) were statistically significant when compared with the control group (P = .005, P = .002, and P = .009, respectively).

CONCLUSIONS

These data suggest that atorvastatin, administered intraperitoneally, is as effective as HA/CMC without an expectable additive effect in preventing postoperative adhesions in rats.

A membrane slurry reduces postoperative adhesions in rat models of abdominal surgery

BACKGROUND

Sodium hyaluronate and carboxymethylcellulose (HA-CMC) membrane is an effective barrier material for limiting postoperative adhesions, but can be difficult to apply in certain situations due to its physical properties. We tested whether HA-CMC membrane hydrated in saline (slurry) is an effective alternative to HA-CMC membrane for preventing surgical adhesions in rat models of abdominal surgery.

MATERIALS AND METHODS

All studies were performed in rat cecal abrasion or sidewall defect models of adhesion formation. Adhesions were examined 7 d after surgery. In separate studies, the effects of variations in slurry composition, volume, and site of application on anti-adhesive properties were studied and compared with untreated controls. Finally, the effectiveness of HA-CMC membrane slurry for preventing adhesions was compared with that of conventional HA-CMC membrane.

RESULTS

Application of HA-CMC membrane slurry to traumatized tissue resulted in a significant reduction in the incidence of adhesions compared with untreated controls in both rat surgery models. Slurry was equally effective when applied in low and high film-to-volume formulations, but had minimal effect when applied in a small volume or at a location distal to the injury. Comparison of HA-CMC membrane slurry and conventional HA-CMC membrane indicated similar efficacy for reducing postoperative adhesions.

CONCLUSIONS

In rat models of abdominal surgery, HA-CMC membrane slurry reduced postoperative adhesion formation and may be an effective alternative for HA-CMC membrane in situations where its use is limited by its physical properties.

Prevention of postoperative adhesion formation by individual and combined administration of 4 per cent icodextrin and dimetindene maleate

BACKGROUND

To date, no single method has been successful in eliminating peritoneal adhesion formation after major abdominal surgery. This study evaluated the individual and possible synergistic effect of a local intraperitoneal barrier, 4 per cent icodextrin, and an intravenously administered antihistamine drug, dimetindene maleate, in the prevention of adhesion development following surgical trauma.

METHODS

De novo experimental adhesions were induced by standardized trauma of the peritoneum and large bowel in 120 New Zealand White rabbits. The animals were randomized into four groups receiving intraperitoneal saline, intraperitoneal 4 per cent icodextrin (60 ml), intravenous dimetindene maleate (0.1 mg/kg) and 4 per cent icodextrin-dimetindene in combination (n = 30 per group). Ten days later, adhesion scores and incidence were assessed by two independent surgeons. and surface area by computer-aided planimetry.

RESULTS

Treatment with either icodextrin or dimetindene maleate significantly reduced adhesion scores and increased the incidence of adhesion-free animals in an equipotent manner. The effect of combined treatment on severity, incidence and surface area of adhesions was more pronounced than that of each drug administered separately.

CONCLUSION

Combined administration of 4 per cent icodextrin and dimetindene maleate may be used safely and efficaciously to prevent surgically induced adhesions.

Intercoat gel (oxiplex): efficacy, safety, and tissue response in a laparoscopic mouse model

STUDY OBJECTIVE

To study the efficacy and safety of Intercoat gel in a laparoscopic mouse model with pneumoperitoneum-enhanced adhesion formation.

DESIGN

Randomized controlled trial. Evidence obtained from a properly designed, randomized, controlled trial (Canadian Task Force classification I).

SETTING

University laboratory research center.

SUBJECTS

Balb\c female mice 9 to 10 weeks old.

INTERVENTIONS

Two laparoscopic mouse models for adhesion formation were used. In the first model, adhesions following bipolar opposing lesions in the pelvis were enhanced by 60 minutes of carbon-dioxide pneumoperitoneum. In the second model, adhesions were further enhanced by bowel manipulation. The first experiment evaluated the efficacy of Intercoat in both models. The second experiment evaluated the efficacy of Intercoat in the first model, when applied immediately on the lesion, when applied at the end of the pneumoperitoneum, and when applied in the upper abdomen. Biopsy specimens were taken after 7 days and were evaluated after hematoxylin-eosin and CD45 staining.

MEASUREMENTS AND MAIN RESULTS

Qualitative and quantitative adhesion scoring. Morphology was evaluated by standard light microscopy. In both models, Intercoat decreased adhesion formation whether applied immediately on the lesion or at the end of the pneumoperitoneum (qualitative and quantitative scoring p <.0001 and p <.0001, respectively). Intercoat application is associated with tissue redness, vascular congestion, and cellular edema but without an inflammatory reaction. Applied in the upper abdomen, Intercoat does not increase adhesions, but decreases adhesions at higher doses (p =.0024). Intercoat in high doses had a toxic effect (p =.0058).

CONCLUSION

Intercoat is an effective antiadhesion product. It is associated with tissue edema and vasodilatation as observed after 7 days both macroscopically and by histology.

Preventive effects of chemically-modified chitosan film with sodium hyalurate on the ischemia-induced peritoneal adhesion

AIM: To comparatively study the preventive effects of chemically-modified chitosan film with sodium hyalurate on the ischemia-induced peritoneal adhesion in rats.

METHODS: Sixty Sprague-Dawley rats were randomly divided into saline-control group (Group A), chemically-modified chitosan film group (Group B) and sodium hyalurate group (Group C), respectively. The ischemia-induced peritoneal adhesive model was established in the caecums of vermiform processes of the rats, and the ischemia surfaces were correspondingly treated with saline, chemically-modified chitosan film and sodium hyalurate in Group A, B and C. After two and four weeks of the treatments, the abdominal cavities were reopened and the adhesive severity was graded blindly according to the Phillips' method. The caecums of vermiform processes were resected for hydroxyproline (OHP) measurement.

RESULTS: After two and four weeks of the treatments in group B and C, the adhesions were significantly lighter (2 wk: U = 3.000, 8.500, P < 0.001, P = 0.001; 4 wk: U = 2.000, 14.000, P < 0.001, P = 0.003) and the OHP levels were significantly lower (2 wk: 0.193 ± 0.029 mg/mg pr, 0.253 ± 0.028 mg/mg pr vs 0.296 ± 0.031 mg/mg pr, both P < 0.01; 4 wk: 0.179 ± 0.034 mg/mg pr, 0.237 ± 0.035 mg/mg pr vs 0.286 ± 0.036 mg/mg pr, both P < 0.01) than those of Group A, respectively. When group B was compared with group C, the former's adhesions were significantly lighter (P = 0.038, P = 0.015) and the OHP levels were significantly lower (P < 0.001, P = 0.001).

CONCLUSION: The chemically-modified chitosan film is more effective in preventing peritoneal adhesion induced by ischemia than that of sodium hyalurate.

Preventing intraperitoneal adhesions with vitamin E and sodium hyaluronate/carboxymethylcellulose: a comparative study in rats

PURPOSE

To compare the effectiveness of intraperitoneally administered vitamin E with the sodium hyaluronate/carboxymethylcellulose membrane (HA/CBMC) in preventing postoperative intraperitoneal adhesion formation.

METHODS

Sixty Wistar rats underwent a laparotomy and adhesions were induced (IA). The animals were divided into four groups: group 1, control (IA); group 2 (IA + Vitamin E): group 3 (IA+HA/CBMC) and group 4 (IA+ Vitamin E + HA/CBMC). The Vitamin E (groups 2 and 4) and HA/CBMC (groups 3 and 4) were administered intraperitoneally before the abdominal wall was closed. After 30 days, adhesions were classified by an independent surgeon.

RESULTS

Three animals died; one from group 3 and two from group 4. All control animals had substantial adhesions compared with unsubstantial adhesions observed in 11/15 in group 2 (P = 0.000), 11/14 in group 3 (P = 0.001), and 10/13 in group 4 (P = 0.000).

CONCLUSION

Vitamin E, administered intraperitoneally, is as effective as HA/CBMC in preventing postoperative adhesions.

Intra-abdominal use of taurolidine or heparin as alternative products to an antiadhesive barrier (Seprafilm) in adhesion prevention: an experimental study on mice

PURPOSE

Seprafilm (Genzyme Biosurgery, Cambridge, MA) remains a widely used product in postoperative adhesion prevention. This study was designed to compare the antiadhesive effects of taurolidine, heparin, and Seprafilm in a murine cecal abrasion model.

METHODS

Sixty male Balb/c mice underwent a cecal abrasion procedure and were randomized into four groups (n = 15 in each). Groups T, H, and S animals intraperitoneally received taurolidine, heparin, and Seprafilm, respectively, and Group C animals were reserved as control. Animals were killed on Day 21, and the severity of adhesions was evaluated with a scoring system ranging between 0 to 5. In addition, the localizations of the adhesions were questioned.

RESULTS

Five (1 in Group S and 4 in Group H) animals died before they were killed. The deaths were related to intra-abdominal bleeding, and mortality rate was significantly higher in Group H than those in other groups (P < 0.05 for each comparison). The severity of adhesions was significantly less in the study groups than Group C, and in Group H than Groups T and S (P < 0.05 for each comparison). In addition, adhesions located cecum over itself were significantly less in the study groups than the control group, and those between small bowel and cecum were significantly lower in Groups T and S than the control group (P < 0.05 for each comparison).

CONCLUSIONS

All products are effective in adhesion prevention. Heparin use provides the best results but may be associated with a higher mortality rate related to intra-abdominal bleeding. Taurolidine may be an alternative product to Seprafilm , but further studies are required.

Icodextrin and Seprafilm do not interfere with colonic anastomosis in rats

BACKGROUND

Physical barriers and instilled solutions have been studied to prevent intra-abdominal adhesions. However, undesirable side effects of these substances on the healing of intestinal anastomoses may limit their use. This study was designed to compare the effects of antiadhesives on the healing of colonic anastomosis in rats.

METHODS

Sixty female Sprague-Dawley rats were divided into 3 groups of 20. The animals received isotonic saline and 7.5% icodextrin, intraperitoneally after standard left colonic anastomosis. In group 3, Seprafilm was wrapped around the anastomosis and also laid over the abdominal viscera. Half of the animals from each group were killed on postoperative day (POD) 4 and the remaining half on POD 21. Adhesion scoring, bursting pressure and tissue hydroxyproline measurements and histopathological assessment were performed.

RESULTS

Mean hydroxyproline levels were significantly higher in groups receiving icodextrin and Seprafilm compared with the control group, whereas mean bursting pressures were significantly higher in the group that received icodextrin (p < 0.05). Intraperitoneal administration of icodextrin resulted in significant reduction of adhesion formation on POD 21 (p < 0.05).

CONCLUSIONS

Seprafilm does not prevent formation of adhesions as much as icodextrin does, but its effect on the healing of colonic anastomoses is similar.

Escin: inhibiting inflammation and promoting gastrointestinal transit to attenuate formation of postoperative adhesions

Postoperative peritoneal adhesions are common, serious complications of general abdominal and gynecologic surgery that can lead to chronic abdominal pain, intestinal obstruction, and infertility. As yet, there are no ideal drugs that may be prescribed for patients to prevent adhesion formation effectively. In this study the effects of escin, a natural drug, on the various steps of adhesion formation were investigated. The effects of escin on increased vascular permeability induced by acetic acid in a mouse model of acute inflammation, granuloma formation in a subchronic inflammatory rat model, gastrointestinal transit in rats with intestinal paralysis, intestinal motility in postoperative patients, and postoperative adhesion formation in a rat model were observed. It was shown that escin could inhibit acute inflammation and granuloma formation, cause acceleration of gastrointestinal transit, help recover intestinal motility, and attenuate the formation of postoperative adhesions. The findings suggest that escin attenuates the formation of postoperative adhesions by inhibiting inflammation and promoting gastrointestinal transit. Thus it may be concluded that both inhibition of inflammation and increased gastrointestinal motility during the early postoperative period have a positive effect on decreasing the formation of adhesions.