Reduction of post-surgical adhesions with ferric hyaluronate gel: a European study

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.

Fluid and pharmacological agents for adhesion prevention after gynaecological surgery

BACKGROUND

Adhesions are fibrin bands that are a common consequence of gynaecological surgery. They are caused by conditions that include pelvic inflammatory disease and endometriosis. Adhesions are associated with comorbidities, including pelvic pain, subfertility, and small bowel obstruction. Adhesions also increase the likelihood of further surgery, causing distress and unnecessary expenses. Strategies to prevent adhesion formation include the use of fluid (also called hydroflotation) and gel agents, which aim to prevent healing tissues from touching one another, or drugs, aimed to change an aspect of the healing process, to make adhesions less likely to form.

OBJECTIVES

To evaluate the effectiveness and safety of fluid and pharmacological agents on rates of pain, live births, and adhesion prevention in women undergoing gynaecological surgery.

SEARCH METHODS

We searched: the Cochrane Gynaecology and Fertility Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, and Epistemonikos to 22 August 2019. We also checked the reference lists of relevant papers and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials investigating the use of fluid (including gel) and pharmacological agents to prevent adhesions after gynaecological surgery.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. We assessed the overall quality of the evidence using GRADE methods. Outcomes of interest were pelvic pain; live birth rates; incidence of, mean, and changes in adhesion scores at second look-laparoscopy (SLL); clinical pregnancy, miscarriage, and ectopic pregnancy rates; quality of life at SLL; and adverse events.

MAIN RESULTS

We included 32 trials (3492 women), and excluded 11. We were unable to include data from nine studies in the statistical analyses, but the findings of these studies were broadly in keeping with the findings of the meta-analyses. Hydroflotation agents versus no hydroflotation agents (10 RCTs) We are uncertain whether hydroflotation agents affected pelvic pain (odds ratio (OR) 1.05, 95% confidence interval (CI) 0.52 to 2.09; one study, 226 women; very low-quality evidence). It is unclear whether hydroflotation agents affected live birth rates (OR 0.67, 95% CI 0.29 to 1.58; two studies, 208 women; low-quality evidence) compared with no treatment. Hydroflotation agents reduced the incidence of adhesions at SLL when compared with no treatment (OR 0.34, 95% CI 0.22 to 0.55, four studies, 566 women; high-quality evidence). The evidence suggests that in women with an 84% chance of having adhesions at SLL with no treatment, using hydroflotation agents would result in 54% to 75% having adhesions. Hydroflotation agents probably made little or no difference to mean adhesion score at SLL (standardised mean difference (SMD) -0.06, 95% CI -0.20 to 0.09; four studies, 722 women; moderate-quality evidence). It is unclear whether hydroflotation agents affected clinical pregnancy rate (OR 0.64, 95% CI 0.36 to 1.14; three studies, 310 women; moderate-quality evidence) compared with no treatment. This suggests that in women with a 26% chance of clinical pregnancy with no treatment, using hydroflotation agents would result in a clinical pregnancy rate of 11% to 28%. No studies reported any adverse events attributable to the intervention. Gel agents versus no treatment (12 RCTs) No studies in this comparison reported pelvic pain or live birth rate. Gel agents reduced the incidence of adhesions at SLL compared with no treatment (OR 0.26, 95% CI 0.12 to 0.57; five studies, 147 women; high-quality evidence). This suggests that in women with an 84% chance of having adhesions at SLL with no treatment, the use of gel agents would result in 39% to 75% having adhesions. It is unclear whether gel agents affected mean adhesion scores at SLL (SMD -0.50, 95% CI -1.09 to 0.09; four studies, 159 women; moderate-quality evidence), or clinical pregnancy rate (OR 0.20, 95% CI 0.02 to 2.02; one study, 30 women; low-quality evidence). No studies in this comparison reported on adverse events attributable to the intervention. Gel agents versus hydroflotation agents when used as an instillant (3 RCTs) No studies in this comparison reported pelvic pain, live birth rate or clinical pregnancy rate. Gel agents probably reduce the incidence of adhesions at SLL when compared with hydroflotation agents (OR 0.50, 95% CI 0.31 to 0.83; three studies, 538 women; moderate-quality evidence). This suggests that in women with a 46% chance of having adhesions at SLL with a hydroflotation agent, the use of gel agents would result in 21% to 41% having adhesions. We are uncertain whether gel agents improved mean adhesion scores at SLL when compared with hydroflotation agents (MD -0.79, 95% CI -0.82 to -0.76; one study, 77 women; very low-quality evidence). No studies in this comparison reported on adverse events attributable to the intervention. Steroids (any route) versus no steroids (4 RCTs) No studies in this comparison reported pelvic pain, incidence of adhesions at SLL or mean adhesion score at SLL. It is unclear whether steroids affected live birth rates compared with no steroids (OR 0.65, 95% CI 0.26 to 1.62; two studies, 223 women; low-quality evidence), or clinical pregnancy rates (OR 1.01, 95% CI 0.66 to 1.55; three studies, 410 women; low-quality evidence). No studies in this comparison reported on adverse events attributable to the intervention.

AUTHORS' CONCLUSIONS

Gels and hydroflotation agents appear to be effective adhesion prevention agents for use during gynaecological surgery, but we found no evidence indicating that they improve fertility outcomes or pelvic pain, and further research is required in this area. It is also worth noting that for some comparisons, wide confidence intervals crossing the line of no effect meant that clinical harm as a result of interventions could not be excluded. Future studies should measure outcomes in a uniform manner, using the modified American Fertility Society score. Statistical findings should be reported in full. No studies reported any adverse events attributable to intervention.

Effect of Bletilla striata on the Prevention of Postoperative Peritoneal Adhesions in Abrasion-Induced Rat Model

Postoperative peritoneal adhesions (PPAs) constitute a common complication of abdominal surgery with a high incidence. Bletilla striata (BS) is an important hemostatic drug used in China for nearly 2000 years. The purpose of this study was to investigate the effect of Bletilla striata on postoperative intestinal adhesion in rats. PPA was induced by cecal wall abrasion, and Bletilla striata was injected to observe its effect on adhesion in rats. The adhesion and inflammation score were assessed through visual observation and histopathologic evaluation. The levels of interleukin-1 (IL-1β), tumor necrosis factor (TNF-α), and interleukin-17F (IL-17F) in abdominal cavity and interleukin-6 (IL-6) in plasma were measured by enzyme-linked immunosorbent assay (ELISA) at 6 hours, 12 hours, 24 hours, and 1 week after operation. The tissue level of transforming growth factor beta-1 (TGF-β1) was also determined by ELISA on the seventh day after surgery. The expressions of collagen and TNF-α were, respectively, detected by Masson trichrome staining and immunohistochemical staining. The expression of TGF-β1 and alpha smooth muscle actin (α-SMA) was detected by Western blot. The result showed that Bletilla striata has obvious preventive effect on PPAs and celiac inflammation of PPAs. Bletilla striata could significantly reduce the level of IL-17F abdominal cavity and IL-6 in plasma. Masson trichrome staining and immunohistochemical staining results showed that Bletilla striata also decreased the expression of TNF-α and collagen. Western blot results showed that Bletilla striata decreased the expression of α-SMA and TGF-β1. Our results suggest that Bletilla striata decreased the development of abdominal adhesion in abrasion-induced model of rats and reduced the expression of the important substance which increased in PPAs. Bletilla striata can be further studied as a new and cheaper antiadhesive substance.

Paeoniflorin prevents postoperative peritoneal adhesion formation in an experimental rat model

Although materials and modern surgical techniques have been developed to suppress postoperative adhesions, adhesion formation can still occur, and thus, a novel effective anti-adhesion drug is greatly needed. In the present study, we explored the efficacy of paeoniflorin treatment against postoperative peritoneal adhesions and examined the anti-oxidative stress and anti-inflammatory properties of PE. Forty-eight male Sprague-Dawley rats were randomly divided into 6 groups for the study: the sham, control, hyaluronan and three concentrations (10, 20 and 40 mg/kg/d) paeoniflorin groups. Abdominal adhesions were created by abrasion of the caecum and its opposite abdominal wall. In the paeoniflorin groups, the rats were administered daily oral doses of paeoniflorin for 7 days. The abdominal cavities of the rats were reopened with a U-shaped incision to macroscopically grade the adhesions. Histologic analysis was performed, and oxidative stress, inflammatory cytokine, collagen fiber degradation and cytokeratin levels were measured. Macroscopic and histopathological measurements revealed that paeoniflorin reduced peritoneal adhesion and inflammation. Notably, treatment with paeoniflorin reduced the protein levels of TGF-β1, IL-6 and COX-2. The collagen fiber fractions were distinctly lower in the PE groups than in the control group. Western blotting analyses showed that paeoniflorin increased MMP-9 and superoxide dismutase-2 protein expression and sharply reduced α-SMA and COX-2 protein expression. Peritoneal mesothelium cells were more continuous and complete in animals treated with paeoniflorin. Our study suggests that paeoniflorin can be used to ameliorate peritoneal adhesions via anti-oxidative stress and anti-inflammatory actions during the postoperative period.

Efficacy of topical cross-linked hyaluronic acid hydrogel in preventing post laminectomy/laminotomy fibrosis in a rat model

Post-laminectomy/laminotomy epidural fibrosis (EF) has been implicated as an important cause of failed back syndrome (FBS). The various clinical approaches used to control EF yield mixed outcomes. Cross-linked hyaluronic acid hydrogel (cHA) was synthesized to increase mechanical stability and residence time. We evaluated the therapeutic attenuation of proliferative EF in laminectomy/laminotomy groups treated and not treated with cHA. A bilateral T11-L1 total laminectomy or unilateral T12 laminotomy was done on four groups (n = 10 each) of Sprague-Dawley rats and then histologically examined 2 months post-surgery: (I) laminectomy group treated with and (II) not treated with cHA, (III) laminotomy group treated with and (IV) not treated with cHA. The grade of EF, the diameters within the spinal canal, dura mater thickness, and the area of the epidural space, subarachnoid space, and conus medullaris space were assessed. The cHA-treated subgroups (I, III) had a significantly lower grade of EF, thinner dura mater, and larger epidural and subarachnoid spaces than did the control subgroups (II, IV) (p < 0.05). The cHA formed a solid interpositional membrane barrier that prevented invasive fibrosis, and also helped reduce pathological changes to the adjacent structures. In conclusion, topically applied cHA is effective for reducing EF.

Fluid and pharmacological agents for adhesion prevention after gynaecological surgery

BACKGROUND

Adhesions are fibrin bands that are a common consequence of gynaecological surgery. They are caused by various conditions including pelvic inflammatory disease and endometriosis. Adhesions are associated with considerable co-morbidity, including pelvic pain, subfertility and small bowel obstruction. Patients may require further surgery-a fact that has financial implications.

OBJECTIVES

To evaluate the role of fluid and pharmacological agents used as adjuvants in preventing formation of adhesions after gynaecological surgery.

SEARCH METHODS

The following databases were searched up to April 2014: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and PsycINFO. Studies involving hydroflotation, gel and such pharmacological agents as steroids, noxytioline, heparin, promethazine, N,O-carboxymethyl chitosan and gonadotrophin-releasing hormone agonists were evaluated.

SELECTION CRITERIA

Randomised controlled trials investigating the use of fluid and pharmacological agents to prevent adhesions after gynaecological surgery. Gels were defined as fluid agents.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for eligibility, extracted data and evaluated risk of bias. Results were expressed as odds ratios (ORs), mean differences (MDs) or standard mean differences (SMDs) as appropriate, with 95% confidence intervals (CIs).

MAIN RESULTS

Twenty-nine trials were included (3227 participants), and nine were excluded. One study examined pelvic pain and found no evidence of a difference between use of hydroflotation agents and no treatment. We found no evidence that any of the antiadhesion agents significantly affected the live birth rate. When gels were compared with no treatment or with hydroflotation agents at second-look laparoscopy (SLL), fewer participants who received a gel showed a worsening adhesion score when compared with those who received no treatment (OR 0.16, 95% CI 0.04 to 0.57, P value 0.005, two studies, 58 women, I(2) = 0%, moderate-quality evidence) and with those given hydroflotation agents (OR 0.28, 95% CI 0.12 to 0.66, P value 0.003, two studies, 342 women, I(2) = 0%, high-quality evidence). Participants who received steroids were less likely to have a worsening adhesion score (OR 0.27, 95% CI 0.12 to 0.58, P value 0.0008, two studies, 182 women, I(2) = 0%, low-quality evidence). Participants were less likely to have adhesions at SLL if they received a hydroflotation agent or gel than if they received no treatment (OR 0.34, 95% CI 0.22 to 0.55, P value < 0.00001, four studies, 566 participants, I(2) = 0%, high-quality evidence; OR 0.25, 95% CI 0.11 to 0.56, P value 0.0006, four studies, 134 women, I(2) = 0%, high-quality evidence, respectively). When gels were compared with hydroflotation agents, participants who received a gel were less likely to have adhesions at SLL than those who received a hydroflotation agent (OR 0.36, 95% CI 0.19 to 0.67, P value 0.001, two studies, 342 women, I(2) = 0%, high-quality evidence). No studies evaluated quality of life. In all studies apart from one, investigators stated that they were going to assess serious adverse outcomes associated with treatment agents, and no adverse effects were reported.Results suggest that for a woman with a 77% risk of developing adhesions without treatment, the risk of developing adhesions after use of a gel would be between 26% and 65%. For a woman with an 83% risk of worsening of adhesions after no treatment at initial surgery, the chance when a gel is used would be between 16% and 73%. Similarly, for hydroflotation fluids for a woman with an 84% chance of developing adhesions with no treatment, the risk of developing adhesions when hydroflotation fluid is used would be between 53% and 73%.Several of the included studies could not be included in a meta-analysis: The findings of these studies broadly agreed with the findings of the meta-analyses.The quality of the evidence, which was assessed using the GRADE approach, ranged from low to high. The main reasons for downgrading of evidence included imprecision (small sample sizes and wide confidence intervals) and poor reporting of study methods.

AUTHORS' CONCLUSIONS

Gels and hydroflotation agents appear to be effective adhesion prevention agents for use during gynaecological surgery, but no evidence indicates that they improve fertility outcomes or pelvic pain, and further research is required in this area. Future studies should measure outcomes in a uniform manner, using the modified American Fertility Society (mAFS) score. Statistical findings should be reported in full.

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.

Impact of adhesions in colorectal surgery

The extent of the problem of adhesions is considerable and poses a significant burden on healthcare systems, the workload of surgeons and the lives of patients. This paper reviews the work undertaken and the associated evidence for the impact of adhesions. It considers the various options and strategies to reduce adhesions alongside the fundamental necessity for good surgical technique.

Effect of reactive oxygen species scavengers, antiinflammatory drugs, and calcium-channel blockers on carbon dioxide pneumoperitoneum-enhanced adhesions in a laparoscopic mouse model

BACKGROUND

Postoperative adhesions are a clinical problem. They can cause female infertility, intestinal obstruction, chronic pelvic pain, and difficulties at the time of reoperation. A variety of approaches described to prevent adhesions have shown variable and inconsistent results. Therefore, this study aimed to evaluate most known substances in a laparoscopic mouse model to obtain quantitative and comprehensive information on adhesion prevention. Specifically, this first study aimed to investigate the effects of reactive oxygen species (ROS) scavengers, antiinflammatory agents, and a calcium-channel blocker on pneumoperitoneum-enhanced adhesions.

METHODS

Adhesions were induced during laparoscopy in BALB/c female mice by creation of a bipolar lesion. Carbon dioxide (CO2) pneumoperitoneum was maintained for 60 min using humidified CO2. Six experiments were conducted to evaluate the effects of ROS scavengers (superoxide dismutase [SOD], catalase, melatonin, and ascorbic acid), antiinflammatory agents (dexamethasone, tenoxicam, ibuprofen, parecoxib, nimesulide, anti-tumor necrosis factor [TNF]-alpha), and a calcium-channel blocker (diltiazem). Adhesions were scored after 7 days during laparotomy.

RESULTS

Adhesions were reduced by SOD (p < 0.01, proc general linear methods (GLM) of experiments 1 and 2), diltiazem (p = 0.05, Wilcoxon), and dexamethasone (p < 0.03), but not by nonsteroidal antiinflammatory drugs (NSAIDs) nor by anti-TNF-alpha. When all the experiments were grouped for analysis, adhesions also decreased with one and three doses of SOD (p < 0.01 and p < 0.01, respectively) and with one and three doses of ascorbic acid (p < 0.02 and p = 0.05, respectively).

CONCLUSIONS

These experiments confirm that SOD, diltiazem, and dexamethasone can decrease adhesion formation. The absence of effect from the other antiinflammatory drugs and anti-TNF-alpha is surprising.

Prevention of adhesions in gynaecological endoscopy

Adhesions resulting from gynaecological endoscopic procedures are a major clinical, social and economic concern, as they may result in pelvic pain, infertility, bowel obstruction and additional surgery to resolve such adhesion-related complications. Although the minimally invasive endoscopic approach has been shown to be less adhesiogenic than traditional surgery, at least with regard to selected procedures, it does not totally eliminate the problem. Consequently, many attempts have been made to further reduce adhesion formation and reformation following endoscopic procedures, and a wide variety of strategies, including surgical techniques, pharmacological agents and mechanical barriers have been advocated to address this issue. The present review clearly indicates that there is no single modality proven to be unequivocally effective in preventing post-operative adhesion formation either for laparoscopic or for hysteroscopic surgery. Furthermore, the available adhesion-reducing substances are rather expensive. Since excellent surgical technique alone seems insufficient, further research is needed on an adjunctive therapy for the prevention and/or reduction of adhesion formation following gynaecological endoscopic procedures.

A modern biomaterial for adhesion prevention

A biomaterial composed of carboxymethylcellulose, poly(ethylene oxide), and calcium can be prepared in a variety of ways to reduce fibrin deposition and adhesion formation. This biomaterial platform can be formulated into a flowable gel with tissue adherence appropriate for use in minimally invasive surgery. The device remains at the site of placement even in gravitationally dependent areas. A peridural formulation was shown in preclinical studies to be safe and effective in reducing adhesions to dura following spinal surgery. A peritoneal formulation used on pelvic organs following peritoneal cavity surgery was also shown to be safe and effective. A clinical feasibility study showed that patients with severe back pain and lower extremity weakness treated with the peridural formulation, applied over their nerve roots following laminectomy or laminotomy, experienced significantly reduced symptoms when compared with surgery-only controls. The peritoneal formulation was shown in two multicenter feasibility studies of women undergoing pelvic surgery to significantly reduce adhesion formation when compared with surgery-only controls. Confirmation of the feasibility studies awaits results from pivotal clinical trials. These formulations were safe, effective, and easy to use. This biomaterial provided a benefit to patients undergoing surgery where postsurgical adhesion formation is a concern.

Fluid and pharmacological agents for adhesion prevention after gynaecological surgery

BACKGROUND

Pelvic surgery is associated with high rates of both de novo adhesion formation and adhesion reformation. Since subsequent fertility is reduced with increasing severity of periadnexal adhesions, pelvic adhesions will remain a clinical problem in infertility patients. Steroids, antihistamines and heparin were amongst the first substances to be advocated for adhesion prevention. More recently icodextrin 4%, hyaluronic acid agents and SprayGel have been used. This review aims to evaluate the role of fluid and pharmacological agents in the prevention of adhesions in fertility-conserving gynaecological surgery.

OBJECTIVES

To investigate fluid and pharmacological agents for adhesion prevention when used as adjuvants during pelvic surgery.

SEARCH STRATEGY

This review has drawn on the search strategy developed for the Menstrual Disorders and Subfertility Group. The following databases were searched: the Cochrane Menstrual Disorders and Subfertility Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE.

SELECTION CRITERIA

Randomised controlled trials investigating the use of fluid and pharmacological agents to prevent adhesion formation after fertility-conserving gynaecological surgery.

DATA COLLECTION AND ANALYSIS

Data extraction and analysis was performed independently by two authors (Metwally M and Watson A). Two-by-two tables were generated for dichotomous outcomes and expressed as odds ratios (OR) with 95% confidence intervals (CI). For continuous outcomes a standardised mean difference was used.

MAIN RESULTS

There is no evidence of benefit from the use of steroids, dextran or other pharmacological agents in any of the outcomes. The use of hyaluronic acid agents may decrease adhesion formation (OR 0.31, 95% CI 0.19 to 0.51) and prevent the deterioration of pre-existing adhesions (OR 0.28 (95% CI 0.12 to 0.66). There is insufficient evidence for the use of icodextrin 4% or SprayGel as adhesion-preventing agents. None of the studied agents has been shown to improve the pregnancy rate when used as an adjunct during pelvic surgery.

AUTHORS' CONCLUSIONS

The current evidence for the use of fluid and pharmacological agents for the prevention of adhesions is limited. There is no evidence on any benefit for improving pregnancy outcomes when pharmacological and fluid agents are used as an adjunct during pelvic surgery. There is insufficient evidence for the use of the following agents: steroids, icodextrin 4%, SprayGel and dextran in improving adhesions following surgery. There is some evidence that hyaluronic acid agents may decrease the proportion of adhesions and prevent the deterioration of pre existing adhesions. However, due to the limited number of studies available, this evidence should be interpreted with caution and further studies are needed.

Evaluation of hyaluronic acid sheet for the prevention of postlaminectomy adhesions

BACKGROUND CONTEXT

Various materials have been tested for their ability to maintain a barrier between muscles and epidural space in order to physically or chemically inhibit scar ingrowths. Hyaluronic acid (HA) solution and gel have been reported to be effective in preventing adhesions postlaminectomy; however, neither has been used clinically after spinal surgery.

PURPOSE

To determine the efficacy of HA sheet for the prevention of postlaminectomy adhesions compared with that of HA gel or another sheet.

STUDY DESIGN/SETTING

An animal model of lumbar laminectomy in rabbits was used to study postoperative scar tissue formation around the spinal cord. The histologic effects of HA sheet were compared with those of Gelfoam (GF) and further evaluated by an inflammation model using rhTNF-alpha.

PATIENT SAMPLE

Rabbit.

OUTCOME MEASURES

Histologic examination.

METHODS

Five rabbits were killed at 2, 4, 8, and 24 weeks after laminectomy, respectively. Another 18 rabbits were examined in an environment of active inflammation experimentally induced by rhTNF-alpha to compare the effects of HA sheet with those of GF or HA gel. Histologic examination was performed to quantitatively assess invasive scar formation or inflammation postlaminectomy, and then, the histologic effects of HA sheet were compared with those of GF or HA gel.

RESULTS

In the HA group, significantly, the area of subarachnoid space was larger, distance from the surface of dura to scar tissues was greater, the number of inflammatory cells in the scar tissues at the site of laminectomy was less, and enlargement of dura was suppressed. Using an inflammation model, we also demonstrated the efficacy of HA sheet treatment.

CONCLUSIONS

In an experimental laminectomy model, HA sheet formed a solid interpositional membrane barrier and exhibited anti-inflammatory activity. Further investigations will be needed for HA sheet to be used clinically.

Efficacy of three adhesion-preventing agents in reducing severe peritoneal trauma induced by bipolar coagulation in a laparoscopic rat model

OBJECTIVE

To compare the antiadhesion efficacy of three agents (4% icodextrin, ferric hyaluronate gel, and Ringer's lactate) in severe peritoneal trauma caused by bipolar coagulation in a laparoscopic rat model.

DESIGN

Prospective, randomized, blinded experimental study.

SETTING

International Laparoscopic Surgery Centre, Clermont-Ferrand, France.

ANIMAL(S)

Female Sprague-Dawley rats.

INTERVENTIONS

Animals were prospectively randomized to receive one of the three agents or to be controls. Coagulation of the parietal peritoneum was performed using a bipolar 40-W current followed by administration of an antiadhesion agent. Postoperative adhesion assessment was carried out on day 7 in 42 rats.

MAIN OUTCOME MEASURE(S)

Adhesions were scored according to their extent and severity.

RESULT(S)

Adhesions occurred in all rats, however, adhesion and vascular adhesion rate scores were significantly higher in controls compared with treated groups. Adhesions were more likely to be filmy and easily separable in the 4% icodextrin group compared with the Ringer's lactate solution group.

CONCLUSION(S)

Adhesion scores were decreased by the use of antiadherent agents. However, no rats were found to be free of adhesions after severe peritoneal trauma induced by 40-W bipolar coagulation of the peritoneum.

Clinical evaluation of a viscoelastic gel for reduction of adhesions following gynaecological surgery by laparoscopy in Europe

BACKGROUND

Commonly used adhesion prevention devices either cannot be applied or are difficult to use via laparoscopy. A viscoelastic gel was developed specifically for adhesion prophylaxis during minimally invasive surgery.

METHODS

Randomized, third party-blinded, parallel-group design conducted at four centres. Patients (18-46 years old) underwent laparoscopic surgery with second look 6-10 weeks later. Viscoelastic gel coated adnexa and adjacent tissues. Blinded reviews of videotapes were quantified by American Fertility Society (AFS) adhesion scores.

RESULTS

In 25 treatment patients, surgery was performed on 45 adnexa. Coverage of surgical sites at risk for adhesions was typically accomplished with approximately 15 ml of viscoelastic gel which was delivered in approximately 90 s. In 24 control patients, surgery alone was performed on 41 adnexa. Treated adnexa showed a decrease in AFS score (11.9-9.1). In contrast, control adnexa showed an increase in AFS score (8.8-15.8). This difference in second-look AFS scores (42% reduction) is significant (P<0.01). Ninety-three per cent of treated adnexa did not have a worse adhesion score in contrast to 56% of control adnexa. Combining scores into prognostic categories also show significant treatment effect of the viscoelastic gel (P<0.01).

CONCLUSION

Viscoelastic gel was easy to use via laparoscopy and produced significant reduction in adnexal adhesions. It provides benefits to patients undergoing gynaecological surgery.

Comparison of two laparoscopic treatments for experimentally induced abdominal adhesions in pony foals

OBJECTIVE

To compare laparoscopic dissection with-laparoscopic dissection combined with abdominal instillation of ferric hyaluronate gel for the treatment of experimentally induced adhesions in pony foals.

ANIMALS

12 healthy pony foals.

PROCEDURE

A serosal abrasion method was used to create adhesions at 4 sites on the jejunum (day 0). At day 7 laparoscopy was performed and the adhesions observed in each foal were recorded. In group-1 foals (n = 6), the adhesions were separated laparoscopically (treatment 1). In group-2 foals (n = 6), 300 mL of 0.5% ferric hyaluronate gel was infused into the abdomen after the adhesions were separated laparoscopically (treatment 2). At day 24, terminal laparoscopy was performed and the adhesions observed were recorded. Total number of adhesions within each group was compared between day 7 and 24. Data were analyzed to determine whether an association existed between the number of adhesions on day 24 and treatment type.

RESULTS

At day 24, the number of adhesions was significantly decreased within each group, compared with the number of adhesions at day 7 (group-1 foals, 10 vs 22 adhesions; group-2 foals, 3 vs 20 adhesions). Treatment 1 was associated with a significantly higher number of adhesions at day 24, compared with treatment 2 (odds ratio, 4.54; 95% confidence interval, 1.03 to 23.02).

CONCLUSION AND CLINICAL RELEVANCE

Abdominal instillation of 0.5% ferric hyaluronate gel after laparoscopic dissection was a more effective technique than laparoscopic dissection alone to treat experimentally induced adhesions in pony foals. Laparoscopic adhesiolysis following abdominal surgery in foals is a safe and effective technique.

Fewer adhesions induced by laparoscopic surgery?

BACKGROUND

Laparoscopic surgery has potential theoretical advantages over open surgery in reducing the rate of adhesion formation, but very few comparative studies are available to prove this.

METHODS

A literature search was performed within Medline and Cochrane databases using the key words: adhesion*, adhesiolysis, laparoscop*, laparotomy, open surgery. Further articles were identified from the reference lists of retrieved literature. Both clinical and experimental studies comparing laparoscopy and laparotomy with regard to adhesion formation were retained. In each article, the rates of adhesion formation were identified or deduced for the operative site, access wound site, and distant sites.

RESULTS

Fifteen studies from 1987 to 2001 were identified. Most studies assessed the operative site. Thus, three clinical studies and six experimental ones found fewer adhesions following laparoscopy than laparotomy, while other five experimental studies found similar adhesion rates for the two surgical methods. There were fewer adhesions to trocar wounds than to the laparotomy wounds in seven studies and equal rates of adhesion in one study. The problem of distant adhesions is poorly represented in literature; three studies favored laparoscopy as being followed by fewer adhesions. Because of the important differences between studies with regard to the design, end points, and statistical calculations, a metaanalysis could not be achieved. The conclusion is based on the prevalence of evidence.

CONCLUSIONS

All clinical studies and most of the experimental studies found a reduction of adhesion formation after laparoscopic surgery compared to open surgery.

Pelvic Adhesions: Laparoscopic Approach

A retrospective study using the American Fertility Society's Adhesion Scoring Method and the MCASM (More Comprehensive Adhesion Scoring Method) and a prospective, randomized, controlled, multicenter trial (Canadian Task Force Classification I) were conducted. Of 2124 cases operated by laparoscopy, 465 patients had adhesions. Fifty-one female patients underwent open or laparoscopic myomectomy procedures with vs. without application of SprayGel adhesion barrier prevention, followed by second-look laparoscopy to evaluate postoperative adhesions. Details of the 465 cases of adhesiolysis are given. In subgroup 1 (n = 34) there were no preexisting adhesions. All 34 patients were assessed at a second-look laparoscopy for adhesion occurrence after 6-8 weeks; 29.4% were found to have no adhesions and 70.6% of patients had significant or mild adhesions. In subgroup 2, 21 patients who had undergone previous surgery for adhesiolysis were operated upon again, and 24% revealed an increased adhesion score, 57% the same adhesion score, and 19% a reduced adhesion score at second-look laparoscopy. Out of 51 patients enrolled, 45 were randomized to either treatment (n = 24) or control (n = 21). Three to sixteen weeks following surgery, 18 of 24 treatment patients (75%) and 13 of 21 controls (61.9%) had second-look laparoscopies (SLL). SLL showed 5 of 18 treatment patients (27.8%) were adhesion free vs. 1 in 13 of controls (7.7%). Patients randomized to SprayGel treatment were 3.6 times more likely to be adhesion free than patients randomized to control. Compared to the initial surgery, the severity score showed a 22% reduction in the treated group vs. a 39% increase in the control group, and a 12% reduction of adhesion area in the treated group vs. a 37% increase in the control group at SLL. New data confirmed previous knowledge: To avoid adhesions you must avoid surgery. If surgery has to be performed, laparoscopic surgery causes fewer adhesions than laparotomy. SprayGel was shown to be effective in reducing postoperative adhesions after laparoscopic and open myomectomy. Application of this adhesion barrier prevention system is fast, easy, and safe. Further studies are needed to confirm the promising results of this interim analysis.

Pathophysiology of intra-abdominal adhesion and abscess formation, and the effect of hyaluronan

BACKGROUND

Intra-abdominal adhesions and abscesses cause significant morbidity and mortality. The formation of fibrin in the abdominal cavity is a common pathophysiological pathway for both. The aim of this review was to investigate the pathophysiology of intra-abdominal adhesions and abscesses, and to explore the possible sites of action of hyaluronan.

METHODS

Data were reviewed from the literature using the Medline database.

RESULTS

Both surgery and peritonitis disturb the equilibrium between coagulation and fibrinolysis in the abdominal cavity in favour of the coagulation system. Hyaluronan-based agents reduce adhesion formation after surgery. Moreover, hyaluronan solution reduces abscess formation in experimental peritonitis. Possible mechanisms of action include mechanical separation of wound surfaces, improvement of peritoneal healing, modulation of the inflammatory response and enhanced fibrinolysis.

CONCLUSION

Diminished fibrin degradation is a common pathway for the formation of adhesions and abscesses. The potential of hyaluronan-based agents to reduce intra-abdominal adhesions and abscesses in abdominal surgery and sepsis is a promising new concept. Elucidating the mechanisms involved and the clinical application of hyaluronan in peritonitis are challenges for future research.

Effect of an intrathoracic injection of sodium hyaluronic acid on the prevention of pleural thickening in excess fluid of tuberculous thoracic cavity

1. The aim of the present study was to evaluate the effect of a hyaluronate-based gel (HAbg) on the prevention of pleural thickening and adhesion in tuberculous pleural effusions (TPE). 2. Fifty-two patients who had accumulated a medium or large volume of tuberculous thoracic fluid, fluid being bound by fibre tissues and a pleura thickened more than 2 mm were divided randomly into two groups. All patients were all given standard treatments with antituberculous drugs. The HAbg was injected into the thoracic cavity in the treatment group (n = 27 patients), whereas normal saline was introduced into the thoracic cavity in the control group (n = 25 patients). Before and after HAbg injection, routine thoracic fluid examinations (including qualitative protein analysis, cell counts and classification of cell types) and protein quantification were performed. A chest radiograph and B-ultrasound were performed and pulmonary function was tested after 2 weeks and 3 months of thoracic fluid absorption. 3. The results show that patients who were treated with the HAbg had a significantly thinner pleura, a lower protein concentration and white blood cell count in the thoracic fluid and a higher forced expiratory volume in 1 s and forced vital capacity compared with patients in the control group. 4. Intrathoracic HAbg can prevent pleural thickening and improve lung function in patients who have a large amount of TPE.