Fluid dynamics in man of an intraperitoneal drug delivery solution: 4% icodextrin

Optimizing Timing of Intraperitoneal Chemotherapy to Enhance Intravenous Carboplatin Concentration

Despite advances in systemic chemotherapy, patients with gastric cancer (GC) and peritoneal metastases (PMs) continue to have poor prognoses. Intraperitoneal (IP) administration of Paclitaxel (PTX) combined with systemic chemotherapy shows promise in treating PMs from GC. However, methods of drug administration need to be optimized to maximize efficacy. In this study, we utilized a mouse model with PMs derived from a human GC cell line, administering PTX either IP or intravenously (IV), and Carboplatin (CBDCA) IV 0, 1, and 4 days after PTX administration. The PMs were resected 30 min later, and concentrations of PTX and CBDCA in resected tumors were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results indicated that PTX concentrations were higher with IP administration than with IV administration, with significant differences observed on days 0 and 1. CBDCA concentrations 4 days post-IP PTX administration were higher than with simultaneous IV PTX administration. These findings suggest that IP PTX administration enhances CBDCA concentration in peritoneal tumors. Therefore, sequential IV administration of anti-cancer drugs appears more effective than simultaneous administration with IP PTX, a strategy that may improve prognoses for patients with PMs.

Inguinal hernia following the use of fluid anti-adhesive agents in laparoscopic surgery: a literature review and case report

Introduction and importance

Inguinal hernia is a rare complication in females occurring due to the use of common anti-adhesion agents, such as ADEPT. Some complications have been reported to date; however, there are no reported cases of ADEPT-induced inguinal hernia.

Case presentation

A 39-year-old woman underwent laparoscopic ovarian cystectomy for a right ovarian endometrioma, using ADEPT as an anti-adhesion agent. Subsequently, she developed an inguinal hernia diagnosed using pelvic computed tomography. The inguinal mass gradually decreased in size and disappeared four months after, without intervention.

Clinical discussion

While rare complications have been reported, no cases of inguinal hernias induced by anti-adhesion agents have been reported to date. To minimize the risk of this complication, avoiding excessive intra-abdominal pressure to prevent possible peritoneal fluid migration through small orifices into low-pressure areas is advised. Additionally, applying external pressure over the superficial/deep inguinal rings until CO2 is completely removed from the abdominal cavity might be helpful.

Conclusion

Inguinal hernia is a rare anti-adhesion solution complication in females. Minimizing the risk involves avoiding excessive intra-abdominal pressure and applying external pressure over the superficial/deep inguinal rings.

The Future of Adhesion Prophylaxis Trials in Abdominal Surgery: An Expert Global Consensus

Postoperative adhesions represent a frequent complication of abdominal surgery. Adhesions can result from infection, ischemia, and foreign body reaction, but commonly develop after any surgical procedure. The morbidity caused by adhesions affects quality of life and, therefore, it is paramount to continue to raise awareness and scientific recognition of the burden of adhesions in healthcare and clinical research. This 2021 Global Expert Consensus Group worked together to produce consented statements to guide future clinical research trials and advise regulatory authorities. It is critical to harmonize the expectations of research, to both develop and bring to market improved anti-adhesion therapies, with the ultimate, shared goal of improved patient outcomes.

Effects of Icodextrin Solution (Adept®) on Ovarian Cancer Cell Proliferation in an In Vitro Model

Background and objective: Anti-adhesion barriers are currently used during ovarian cancer surgery to decrease adhesion-related morbidity. Adept® (4% icodextrin) solution, a liquid anti-adhesion material, has been widely used during gynecologic surgeries, though the risk of this barrier for oncologic surgery is controversial. The aim of this study was to determine the effect of Adept® solution on the proliferation of ovarian cancer cells. Materials and methods: We assessed the dose- and time-dependent effects of icodextrin on the growth and proliferation of OVCAR-3 and A2780 human ovarian tumor cell lines in vitro. Cell growth was determined by cell number counting. Expressions of cell cycle-regulation proteins (cyclin D1 and cyclin B1) were determined using Western blot analysis. Results: Adept® did not significantly increase ovarian cancer cell growth when tested at various concentrations (0, 1, 5, 10, 15, and 20%, equal to 0, 0.04, 0.2, 0.4, 0.6 and 0.8% icodextrin) and different time points (1–3 days) compared to control cells. Moreover, the protein levels of cyclin D1 and B1 were not overexpression-elevated in icodextrin-treated ovarian cancer cells, either with an increasing concentration or with an increasing treated time. These results demonstrated that Adept® does not activate the growth or proliferation of ovarian cancer cells in either a dose- or time-dependent manner. Conclusions: This study supports the use of Adept® solution as a safe anti-adhesion barrier for ovarian cancer surgery, though further in vivo studies are necessary.

Advancement of Biomaterial-Based Postoperative Adhesion Barriers

Postoperative peritoneal adhesion (PPA) is a prevalent incidence that generally happens during the healing process of traumatized tissues. It causes multiple severe complications such as intestinal obstruction, chronic abdominal pain, and female infertility. To prevent PPA, several antiadhesion materials and drug delivery systems composed of biomaterials are used clinically, and clinical antiadhesive is one of the important applications nowadays. In addition to several commercially available materials, like film, spray, injectable hydrogel, powder, or solution type have been energetically studied based on natural and synthetic biomaterials such as alginate, hyaluronan, cellulose, starch, chondroitin sulfate, polyethylene glycol, polylactic acid, etc. Moreover, many kinds of animal adhesion models, such as cecum abrasion models and unitary horn models, are developed to evaluate new materials' efficacy. A new animal adhesion model based on hepatectomy and conventional animal adhesion models is recently developed and a new adhesion barrier by this new model is also developed. In summary, many kinds of materials and animal models are studied; thus, it is quite important to overview this field's current progress. Here, PPA is reviewed in terms of the species of biomaterials and animal models and several problems to be solved to develop better antiadhesion materials in the future are discussed.

Peritoneal adhesions: Occurrence, prevention and experimental models

Peritoneal adhesions (PA) are a postoperative syndrome with high incidence rate, which can cause chronic abdominal pain, intestinal obstruction, and female infertility. Previous studies have identified that PA are caused by a disordered feedback of blood coagulation, inflammation, and fibrinolysis. Monocytes, macrophages, fibroblasts, and mesothelial cells are involved in this process, and secreted signaling molecules, such as tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10), tissue plasminogen activator (tPA), and type 1 plasminogen activator inhibitor (PAI-1), play a key role in PA development. There have been many attempts to prevent PA formation by anti-PA drugs, barriers, and other therapeutic methods, but their effectiveness has not been widely accepted. Treatment by biomaterial-based barriers is believed to be the most promising method to prevent PA formation in recent years. In this review, the pathogenesis, treatment approaches, and animal models of PA are summarized and discussed to understand the challenges faced in the biomaterial-based anti-PA treatments.

[Existing and forward-looking ways to prevent adhesions in IPOM hernia repair. A research overview]

IPOM intraperitoneal hernia repair, in comparison with other abdominal wall reconstruction methods, has a number of significant advantages. Among them are a reduction in operative time, low rate of surgical site infections, quick rehabilitation, and good cosmetic results. At the same time, one of the main constraining factors for its widespread use is the rather high frequency of adhesion formation between the implant and the abdominal organs. The first way to solve this serious problem is to improve the structure of the implant itself, and in the first place, its anti-adhesive layer. The second is the search for adjuvant tools that work in «problematic» areas, prone to adhesions formation, such as the points of implant fixation, its edges, or the areas of damage to antiadhesive layer due to a violation of the operative technique. It is desirable that they could exert their effect also in other parts of the abdominal cavity, which, despite the absence of a zone of «active» intervention, can also undergo adhesions. Based on this, the purpose of this review was to summarize modern data on the anti-adhesive activity of both composite implants and specialized membranes and liquid agents.

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.

Predicting drug delivery efficiency into tumor tissues through molecular simulation of transport in complex vascular networks

Efficient delivery of anticancer drugs into tumor tissues at maximally effective and minimally toxic concentrations is vital for therapeutic success. At present, no method exists that can predict the spatial and temporal distribution of drugs into a target tissue after administration of a specific dose. This prevents accurate estimation of optimal dosage regimens for cancer therapy. Here we present a new method that predicts quantitatively the time-dependent spatial distribution of drugs in tumor tissues at sub-micrometer resolution. This is achieved by modeling the diffusive flow of individual drug molecules through the three-dimensional network of blood-vessels that vascularize the tumor, and into surrounding tissues, using molecular mechanics techniques. By evaluating delivery into tumors supplied by a series of blood-vessel networks with varying degrees of complexity, we show that the optimal dose depends critically on the precise vascular structure. Finally, we apply our method to calculate the optimal dosage of the cancer drug doxil into a section of a mouse ovarian tumor, and demonstrate the enhanced delivery of liposomally administered doxorubicin when compared to free doxorubicin. Comparison with experimental data and a multiple-compartment model show that the model accurately recapitulates known pharmacokinetics and drug-load predictions. In addition, it provides, for the first time, a detailed picture of the spatial dependence of drug uptake into tissues surrounding tumor vasculatures. This approach is fundamentally different to current continuum models, and reveals that the target tumor vascular topology is as important for therapeutic success as the transport properties of the drug delivery platform itself. This sets the stage for revisiting drug dosage calculations.

Adhesion Prevention to Polypropylene Meshes Using Combined Icodextrin Four Percent and Dimetindene Maleate

BACKGROUND

The use of surgical meshes in ventral hernia repair has significantly reduced hernia recurrence rates. However, when placed intraperitoneally prosthetic materials can trigger the development of peritoneal adhesions. The present experimental study evaluated the combined icodextrin 4% and dimetindene maleate treatment in preventing peritoneal adhesion formation to polypropylene and titanium-coated polypropylene meshes.

MATERIALS AND METHODS

Sixty female white rabbits were divided into four groups. A 2 × 2 cm piece of mesh was fixed to intact peritoneum in all animals through a midline laparotomy. A lightweight polypropylene mesh was implanted in groups 1 and 2 and a titanium-coated polypropylene mesh in groups 3 and 4. Groups 2 and 4 were treated, intraoperatively, with intravenous dimetindene maleate (0.1 mg/kg) and intraperitoneal solution of icodextrin 4% (20 mL/kg) and for the next 6 d with dimetindene maleate intramuscularly. The observation period lasted 15 d. Adhesion scores, percentage of mesh affected surface, tissue hydroxyproline levels, and tissue histopathology were examined.

RESULTS

All animals in group 1 and 57% of animals in group 3 presented postoperative adhesions. The combination of antiadhesives significantly reduced the extent and severity of adhesions as well as the hydroxyproline levels in groups 2 and 4 compared with groups 1 and 3. On microscopic evaluation, animals in group 1 exhibited higher inflammation scores compared with group 2, whereas animals in groups 2 and 4 had better mesotheliazation compared with groups 1 and 3.

CONCLUSIONS

The combined administration of icodextrin 4% and dimetindene maleate reduces the extent and severity of adhesions and may be successfully used to prevent adhesion formation after mesh intraperitoneal placement.

Polymer materials for prevention of postoperative adhesion

Postoperative adhesion (POA) is a common complication that often occurs after a variety of surgeries, such as plastic surgery, repair operations of abdominal, pelvic, and tendon, and so forth. Moreover, POA leads to chronic abdominal pain, secondary infertility in women, intestinal obstruction, and other severe complications, which significantly reduce the life quality of patients. In order to prevent the formation of POA, a number of strategies have been developed, among which an emerging method is physical barriers consisting of polymer materials. This review highlights the most commonly used natural and synthetic polymer materials in anti-adhesion physical barriers. The specific features of polymer materials are analyzed and compared, and the possible prospect is also predicted.

STATEMENT OF SIGNIFICANCE

Postoperative adhesion (POA) is a serious complication accompanied with various surgeries. Polymer material-based physical barriers have attracted a large amount of attention in POA prevention. The polymer barriers can effectively avoid the formation of fibrous tissues among normal organs by reducing the interconnection of injured tissues. In this review, specific features of the natural and synthetic polymer materials for application in POA prevention were presented, and the possible prospects were predicted. All in all, our work can provide inspiration for researchers to choose proper polymer materials for preclinical and even clinical anti-adhesion studies.

Optimal drug delivery for intraperitoneal paclitaxel (PTX) in murine model

Background

Repeated intraperitoneal (IP) administration of paclitaxel (PTX) with concurrent systemic chemotherapy is clinically effective for the treatment of peritoneal metastases (PM) from gastric cancer. However, it is unclear how biochemical modifications may affect the pharmacokinetics and bioavailability of IP administered PTX.

Methods

In a xenograft PM model using human gastric cancer cells, MKN45, fluorescein-conjugated PTX (OG-PTX) was given IP and the intra-tumor distribution of PTX examined with fluorescein microscopy.

Results

After IP injection, PTX was seen to directly infiltrate up to several hundred micrometers from the surface of the PM. Co-injection with 5 % non-animal stabilized hyaluronic acid increased PTX infiltration and suppressed the development of PM more efficiently than PTX alone. PTX solubilized with amphiphilic polymer composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) and n-butyl methacrylate (BMA) efficiently formed a micellar formation 50-100 nm in diameter. IP injection of the nanomicellar PTX (PTX-30W) also showed significantly enhanced tumor infiltration and further inhibition of the growth of PM compared with PTX solubilized with Cremophor-ethanol (PTX-Cre). Finally, IP administration of NK105, another nanomicellar PTX, inhibited the growth of subcutaneous tumors as well as PM, compared with conventional PTX-Cre in the same murine model.

Conclusions

PTX administered IP directly infiltrates PM and are thus a useful strategy for the treatment of PM. Drug modification with nanotechnology may further enhance penetration of PM resulting in improved clinical efficacy.

Role of the peritoneal cavity in the prevention of postoperative adhesions, pain, and fatigue

A surgical trauma results within minutes in exudation, platelets, and fibrin deposition. Within hours, the denuded area is covered by tissue repair cells/macrophages, starting a cascade of events. Epithelial repair starts on day 1 and is terminated by day 3. If repair is delayed by decreased fibrinolysis, local inflammation, or factors in peritoneal fluid, fibroblast growth starting on day 3 and angiogenesis starting on day 5 results in adhesion formation. For adhesion formation, quantitatively more important are factors released into the peritoneal fluid after retraction of the fragile mesothelial cells and acute inflammation of the entire peritoneal cavity. This is caused by mechanical trauma, hypoxia (e.g., CO₂ pneumoperitoneum), reactive oxygen species (ROS; e.g., open surgery), desiccation, or presence of blood, and this is more severe at higher temperatures. The inflammation at trauma sites is delayed by necrotic tissue, resorbable sutures, vascularization damage, and oxidative stress. Prevention of adhesion formation therefore consists of the prevention of acute inflammation in the peritoneal cavity by means of gentle tissue handling, the addition of more than 5% N₂O to the CO₂ pneumoperitoneum, cooling the abdomen to 30°C, prevention of desiccation, a short duration of surgery, and, at the end of surgery, meticulous hemostasis, thorough lavage, application of a barrier to injury sites, and administration of dexamethasone. With this combined therapy, nearly adhesion-free surgery can be performed today. Conditioning alone results in some 85% adhesion prevention, barriers alone in 40%-50%.

Adhesion prevention agents for gynaecological surgery: an overview of Cochrane reviews

BACKGROUND

Intraperitoneal adhesions are associated with considerable co-morbidity and have large financial and public health repercussions. They have secondary effects that include chronic pelvic pain, dyspareunia, subfertility and bowel obstruction. In women with adhesions, subsequent surgery is more difficult, often takes longer, and is associated with a higher complication rate (Broek 2013). The significant burden of adhesions has led to the development of several anti-adhesion agents, although there is disagreement as to their relative effectiveness.

OBJECTIVES

To summarise evidence derived from Cochrane systematic reviews on the clinical safety and effectiveness of solid agents, gel agents, liquid agents and pharmacological agents, used as adjuvants to prevent formation of adhesions after gynaecological pelvic surgery.

METHODS

The Cochrane Database of Systematic Reviews was searched using the keyword 'adhesion' up to August 2014. The Cochrane information management system was also searched for any titles or protocols of reviews in progress. Two review authors independently extracted information from the reviews, with disagreements being resolved by a third review author. The quality of the included reviews was described in a narrative manner, and the AMSTAR tool was used to formally assess each review included in this overview. The quality of evidence provided in the original reviews was described using GRADE methods.

MAIN RESULTS

We included two reviews, one with 18 studies comparing solid agents (oxidised regenerated cellulose expanded polytetrafluoroethylene, sodium hyaluronate and carboxymethylcellulose, and fibrin sheets) with control or with each other. The other review included 29 studies which compared liquid agents (4% icodextrin, 32% dextran, crystalloids), gel agents (carboxymethylcellulose and polyethylene oxide, polyethylene glycol gels, hyaluronic acid based gel, 0.5% ferric hyaluronate gel, sodium hyaluronate spray) and pharmacological agents (gonadotrophin-releasing hormone agonist, reteplase plasminogen activator, N,O-carboxymethyl chitosan, steroid agents, intraperitoneal noxytioline, intraperitoneal heparin, systemic promethazine) with control or each other. Both reviews met all of the criteria of the AMSTAR assessment.The reviews included as outcomes both the primary outcomes of this overview (pelvic pain, pregnancy, live birth rate and quality of life (QoL)) and our secondary outcomes (adverse effects, presence or absence of adhesions at second-look laparoscopy (SLL) and adhesion score). However, neither of the reviews identified any primary studies of solid, gel or pharmacological agents that reported any of our primary outcomes. The only studies in either review that reported any of our primary outcomes were studies comparing liquid agents versus control (saline or Hartmann's solution), which reported pelvic pain (two studies), live birth (two studies) and pregnancy (three studies).An external source of funding was stated for 25 of the 47 studies across both reviews; in 24 of these studies the funding was commercial. Solid agents (18 studies)None of our primary outcomes were reported. Adverse events were reported as an outcome by only 9 of the 18 studies. These reported no adverse events. Liquid agents (nine studies)There was no evidence of a difference between liquid agents and control (saline or Hartmann's solution) with respect to pelvic pain (odds ratio (OR) 0.65, 95% confidence interval (CI) 0.37 to 1.14, 1 study, n = 286, moderate quality evidence), pregnancy rate (OR 0.64, 95% CI 0.36 to 1.14, 3 studies, n = 310, moderate quality evidence) or live birth rate (OR 0.67, 95% CI 0.29 to 1.58, 2 studies, n = 208, moderate quality evidence). No studies of liquid agents reported QoL. Adverse events were not reported as an outcome by any of the nine studies. Gel agents (seven studies)None of our primary outcomes were reported. Adverse events were not reported as an outcome by any of the seven studies. Pharmacological agents (seven studies)None of our primary outcomes were reported. Adverse events were reported as an outcome by only one of the seven primary studies. This study reported no evidence of difference in ectopic pregnancy rates between intraperitoneal noxytioline and no treatment (OR 4.91, 95% CI 0.45 to 53.27, 1 study, n = 33, low quality evidence).

AUTHORS' CONCLUSIONS

There is insufficient evidence to allow us to draw any conclusions about the effectiveness and safety of anti-adhesion agents in gynaecological surgery, due to the lack of data on pelvic pain, fertility outcomes, quality of life or safety. A substantial proportion of research in this field has been funded by private companies that manufacture these agents, and further high powered, independent trials will be needed before definitive conclusions can be made.

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.

Comparison of 2 Different Barrier Solutions (icodextrin 4% vs. dextran 70) used as Adhesion-prevention Agents after Microsurgical Adnexal Operations

In this prospective randomized clinical trial, 2 different barrier solutions (icodextrin 4% vs. dextran 70) were compared with regard to their antiadhesive properties, their tolerance and their persistence in situ. To this end, 45 patients suffering from infertility due to adnexal adhesions with indication for microsurgical adhesiolysis were randomized to 2 treatment groups. In advance of abdominal closure, patients were randomized to receive either 1,000 mL of icodextrin 4% solution (n = 23) or 300 mL dextran 70 instillation (n = 22). Serial transvaginal ultrasonographic scans were conducted on days 1, 3, 5 and 7 after surgery to measure the remaining volumes of each barrier solution. Seven days after initial surgery, a second-look laparoscopy was performed; remaining fluids were aspirated and measured and adhesions were rescored (final adhesion score). Differences between treatment groups were not significant (p = 0.775). With regard to their tolerance, the advantages of the icodextrin 4% solution became obvious, as edema of vulva and abdomen occurred more frequently after dextran 70 instillation.

In conclusion, microsurgical adhesiolysis and application of icodextrin 4% solution or dextran 70 as adhesion-prevention agent resulted in reduction of incidence, extent and severity of adhesions. Both solutions were well tolerated.

Intraperitoneal chemotherapy against peritoneal carcinomatosis: current status and future perspective

Peritoneal carcinomatosis (PC), caused by advanced abdominal malignancies, such as those of the ovarian and gastrointestinal tracts, has an extremely poor prognosis. Intraperitoneal (IP) chemotherapy has been clinically applied for several decades, but its clinical efficacy has not been fully determined. An accumulating body of evidence suggests that cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) is the optimal treatment for selected patients with ovarian and colorectal cancers with PC. Recent studies suggest that IP administration of taxane with systemic chemotherapy in a neoadjuvant setting improves patient survival in gastric cancer with PC. The pharmacokinetics of IP-administered drugs should be primarily considered in order to optimize IP chemotherapy. Therefore, the development of specific IP drugs using newly emerging molecular targeted reagents or new drug delivery systems, such as nanomedicine or controlled absorption/release methods, is essential to improve the efficacy of IP chemotherapy.

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.

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.

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.

Optimization of drug delivery systems for intraperitoneal therapy to extend the residence time of the chemotherapeutic agent

Intraperitoneal (IP) chemotherapy is an effective way of treating peritoneal carcinomatosis of colorectal origin after complete cytoreduction. Although IP therapy has been already performed for many years, no standardized treatment design has been developed in terms of schedule, residence time, drug, or carrier solution. Because of the fast clearance of the conventional intravenous (IV) drug delivery systems used for IP therapy, a lot of research is performed to optimize IP drug delivery and extend the residence time of the cytotoxic agent in the peritoneal cavity. This paper reviews the recent advances made in drug delivery systems for IP chemotherapy, discussing the use of microparticles, nanoparticles, liposomes, micelles, implants, and injectable depots for IP delivery.

Adhesion prevention in myomectomy

Adhesions are abnormal fibrous connections, joining tissue surfaces in abnormal locations. Adhesions form after any trauma involving the peritoneum and the injured tissue surface or directly between the injured tissue surfaces. The ideal anti-adhesion agent should be safe, efficacious, easy to use in all types of surgery, and economical. It should prevent adhesions at the site of surgery as well as throughout the peritoneal cavity. Needless to say, the ideal agent is still elusive.

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.

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.

Oncolytic adenoviral gene therapy in ovarian cancer: why we are not wasting our time

Preclinical gene-therapy studies in the past 15 years have repeatedly raised hopes that we were about to enter a brave new era. However, many clinical trials have disappointed. For tumor types with poor response rates to first-line conventional cytotoxic chemotherapy and/or high rates of chemorefractory disease, there remain very few treatment options. In this article we review gene therapy within the context of ovarian cancer. We examine why clinical data have been discouraging and discuss how the lessons learned from earlier trials are being applied to current research.

Pharmacokinetics and tissue distribution of intraperitoneal 5-fluorouracil with a novel carrier solution in rats

AIM: To compare the pharmacokinetics and tissue distribution of 5-fluorouracil administered intraperitoneally with two isotonic carrier solutions: HAES-steri (neotype 6% hydroxyethyl starch), a novel carrier solution with middle molecular weight and physiologic saline (0.9% sodium chloride solution), a traditional carrier solution for intraperitoneal chemotherapy, in rats.

METHODS: A total of 60 Sprague Dawley rats were randomized into groups according to the carrier solution administered. Each group was further randomized according to the intraperitoneal dwell period (1, 3, 6, 12, 18 and 24 h). At the end of the procedure the rats were killed, the peritoneal fluid was withdrawn completely and quantitated. Drug concentrations in peritoneal fluid, plasma, and tissues were determined by high-performance liquid chromatography.

RESULTS: The mean volumes remaining in the peritoneal cavity were significantly higher with HAES-steri than those with physiologic saline at 1, 6, 12, 18, and 24 h (P = 0.047, 0.009, 0.005, 0.005 and 0.005 respectively, the percentages of remaining peritoneal fluid volume were 89.9 ± 5.6 vs 83.4 ± 4.9, 79.9 ± 2.8 vs 56.2 ± 15.7, 46.8 ± 5.5 vs 24.7 ± 9.7, 23.0 ± 2.8 vs 0.0 ± 0.0 and 4.2 ± 1.7 vs 0.0 ± 0.0 respectively). Mean concentrations in peritoneal fluid were significantly higher with HAES-steri than those with physiologic saline at 3, 12 and 18 h (P = 0.009, 0.009 and 0.005 respectively, the concentrations were 139.2768 ± 28.2317 mg/L vs mg/L, 11.5427 ± 3.0976 mg/L vs 0.0000 ± 0.0000 mg/L and 4.7724 ± 1.0936 mg/L vs 0.0000 ± 0.0000 mg/L respectively). Mean plasma 5-fluorouracil concentrations in portal vein were significantly higher with HAES-steri at 3, 12, 18 and 24 h (P = 0.009, 0.034, 0.005 and 0.019 respectively, the concentrations were 3.3572 ± 0.8128 mg/L vs 0.8794 ± 0.2394 mg/L, 0.6203 ± 0.9935 mg/L vs 0.0112 ± 0.0250 mg/L, 0.3725 ± 0.3871 mg/L vs 0.0000 ± 0.0000 mg/L, and 0.2469 ± 0.1457 mg/L vs 0.0000 ± 0.0000 mg/L respectively), but significantly lower at 1 h (P = 0.009, the concentrations were 4.1957 ± 0.6952 mg/L vs 7.7406 ± 1.2377 mg/L). There were no significant differences in the plasma 5-fluorouracil in inferior caval vein at each time-point. 5-fluorouracil concentrations were significantly greater with HAES-steri at 18 h in gastric tissue (P = 0.016, the concentrations were 0.9486 ± 0.8173 mg/L vs 030392 ± 0.0316 mg/L), at 18 h in colon (P = 0.009, the concentrations were 0.1730 ± 0.0446 mg/L vs 0.0626 ± 0.0425 mg/L), at 3, 6, 12 and 24 h in liver (P = 0.009, 0.013, 0.034 and 0.013 respectively, the concentrations were 0.6472685 ± 0.5256 mg/L vs 0.1554 ± 0.1043mg/L, 0.8606826 ± 0.7155 mg/L vs 0.0014 ± 0.0029 mg/L, 0.0445 ± 0.0330 mg/L vs 0.0797 ± 0.1005 mg/L and 0.0863 ± 0.0399 mg/L vs 0.0034 ± 0.0075 mg/L respectively) and at 18 h in lung (P = 0.009, the concentrations were 0.0886 ± 0.0668 mg/L vs 0.0094 ± 0.0210 mg/L). There were no differences in 5-fluorouracil concentrations in renal tissue at each time-point.

CONCLUSION: The use of intraperitoneal 5-fluoro-uracil with HAES-Steri carrier solution provides a pharmacokinetic advantage for a local-regional killing of residual tumor cells and improve the accumulated penetrability of 5-fluorouracil with decreased systemic toxicity. Further clinical feasibility studies on the use of HAES-steri as carrier solution for intraperitoneal chemotherapy with 5-fluorouracil are warranted.

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.

Polymers in the prevention of peritoneal adhesions

Peritoneal adhesions are serious complications of surgery, and can result in pain, infertility, and potentially lethal bowel obstruction. Pharmacotherapy and barrier devices have reduced adhesion formation to varying degrees in preclinical studies or clinical trials; however, complete prevention of adhesions remains to be accomplished. We and others have hypothesized that the limitations of the two approaches could be overcome by combining their strengths in the context of controlled drug delivery. Here we review the role of polymeric systems in the prevention of peritoneal adhesions, with an emphasis on our recent work in developing and applying polymeric drug delivery systems such as nano- or microparticles, hydrogels, and hybrid systems for peritoneal use.

A feasibility, pharmacokinetic and frequency-escalation trial of intraperitoneal chemotherapy in high risk gastrointestinal tract cancer

AIMS

To assess the feasibility, pharmacokinetics and maximum tolerable frequency (MTF) of intraperitoneal (IP) 5-fluorouracil and leucovorin (FU/LV) added, as a regional boost, to intravenous chemotherapy after resection of gastrointestinal cancer.

METHODS

Fifty-three patients were recruited following gastrointestinal cancer resection (43 colon; 10 stomach/small bowel) with serosal involvement. Peritoneal ports were implanted and IP fluid distribution evaluated ultrasonically. Twelve patients were studied for pharmacokinetics; 44 (41 evaluable) for MTF. Treatment was weekly intravenous bolus FU/LV for 6 months; to this was added IP FU/LV (400/20 mg/m(2) in 1500 ml 4% icodextrin) with increasing frequency from 4 weekly to 1 weekly in four successive cohorts.

RESULTS

Peritoneal fluid distribution was excellent. Intraperitoneal FU exposure (AUC) after IP treatment was >1000-fold plasma AUC after IP treatment (regional pharmacokinetic advantage), and >100-fold plasma AUC after intravenous treatment (regional therapeutic advantage). IP therapy was well tolerated if given every 4, 3 or 2 weeks, but not weekly: 11/13, 7/8, 10/13 and 0/7 patients respectively completed treatment without IP modification in these cohorts. Problems with peritoneal access occurred in 20% of patients.

CONCLUSION

Adding fortnightly IP FU/LV to a standard intravenous regimen is safe, tolerable and provides high peritoneal FU exposure. More reliable peritoneal access is needed to improve the feasibility of this otherwise promising therapeutic approach.

Peritoneal adhesions: facing the enemy

BACKGROUND

Postsurgical adhesions severely affect the quality of life of millions of people worldwide. Numerous attempts have been made to prevent or reduce the incidence of peritoneal adhesions, but with limited success.

DATA SOURCES

An extensive Medline search, textbooks, scientific reports and scientific journals are the data sources. We also reviewed reference lists in all articles retrieved in the search as well as those of major texts regarding postsurgical intraperitoneal adhesion formation.

CONCLUSIONS

A multifactorial approach including minimizing tissue injury, prophylactic antibiotic usage to reduce infectious morbidity, and biochemical agents with or without biomechanical barriers will reduce the amount and severity of adhesions. However, further research is needed to establish the safety, effectiveness and also the cost/benefit ratio of these substances in human subjects.

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.

Adept (icodextrin 4% solution) reduces adhesions after laparoscopic surgery for adhesiolysis: a double-blind, randomized, controlled study

OBJECTIVE

To evaluate the efficacy and safety of Adept (4% icodextrin solution) in reducing adhesions after laparoscopic gynecological surgery involving adhesiolysis.

DESIGN

Multicenter, prospective, randomized, double-blind study comparing Adept with lactated Ringer's solution (LRS).

PATIENT(S)

Four hundred two patients randomized intraoperatively to Adept (n = 203) or LRS (n = 199) returned for second laparoscopy within 4-8 weeks. Incidence, severity, and extent of adhesions were determined on both occasions.

MAIN OUTCOME MEASURE(S)

The primary efficacy measure defined by the Food and Drug Administration was the number of patients achieving clinical success with adhesion treatment. Other measures included incidence and American Fertility Society (AFS) scores.

RESULT(S)

Significantly more Adept patients achieved clinical success than did LRS patients (49% vs. 38%). In infertility patients, Adept demonstrated particular clinical success compared with LRS (55% vs. 33%). This was reflected in the number of patients with a reduced AFS score (53% vs. 30%) and in fewer patients with a moderate/severe AFS category score (43% vs. 14%). Safety was comparable in both groups. Most events were related to the surgery, with an increase in transient labial edema in the Adept group.

CONCLUSION(S)

This is the first randomized, double-blind trial of an adhesion reduction agent. It demonstrated that Adept is a safe and effective adhesion reduction agent in laparoscopy.

Icodextrin enhances survival in an intraperitoneal ovarian cancer murine model utilizing gene therapy

OBJECTIVE

Icodextrin, a novel glucose polymer solution utilized for peritoneal dialysis, has been demonstrated to have prolonged intraperitoneal (IP) instillation volumes in comparison to standard PBS solutions. In an animal model of ovarian cancer, we explored whether a survival advantage exists utilizing icodextrin rather than PBS as a delivery solution for an infectivity enhanced virotherapy approach.

METHODS

Initial experiments evaluated whether icodextrin would adversely affect replication of a clinical grade infectivity enhanced conditionally replicative adenovirus (Delta24-RGD). Virus was added to prepared blinded solutions of PBS or icodextrin (20%) and then evaluated in vitro in various human ovarian cancer cell lines (SKOV3.ip1, PA-1, and Hey) and in vivo in a SKOV3.ip1 human ovarian cancer IP murine model. Viral replication was measured by detecting adenovirus E4 gene levels utilizing QRT-PCR. Survival was subsequently evaluated in a separate SKOV3.ip1 ovarian cancer IP murine model. Cohorts of mice were treated in blinded fashion with PBS alone, icodextrin alone, PBS+Delta24-RGD, or icodextrin+Delta24-RGD. Survival data were plotted on Kaplan-Meier curve and statistical calculations performed using the log-rank test.

RESULTS

There was no adverse affect of icodextrin on vector replication in the ovarian cancer cell lines nor murine model tumor samples evaluated. Median survival in the IP treated animal cohorts was 23 days for the PBS group, 40 days for the icodextrin group, 65 days for the PBS+Delta24-RGD group, and 105 days for icodextrin+Delta24-RGD (p=0.023). Of note, 5 of the 10 mice in the icodextrin+Delta24-RGD group were alive at the end of the study period, all without evidence of tumor (120 days).

CONCLUSIONS

These experiments suggest that the use of dialysates such as icodextrin may further enhance the therapeutic effects of novel IP virotherapy and other gene therapy strategies for ovarian cancer. Phase I studies utilizing icodextrin-based virotherapy for ovarian cancer are currently in development.

Innovative barriers for peritoneal adhesion prevention: liquid or solid? A rat uterine horn model

OBJECTIVE

To compare the effects of solid barriers (PDLA membrane and foil, Interceed), innovative barrier solutions (Adept and Hyalobarrier Gel, phospholipid emulsion), and Ringer's lactate solution in preventing postsurgical peritoneal adhesions in the rat.

DESIGN

Prospective, randomized experimental study.

SETTING

Rat model in an academic research environment.

ANIMAL(S)

Female, nonpregnant Wistar rats.

INTERVENTION(S)

Standardized surgical injuries were applied to the parietal and visceral peritoneum and the uterine horns. The barrier agents were applied and the wound was closed. A second-look laparoscopy was performed 31 days after surgery to assess adhesion formation.

MAIN OUTCOME MEASURE(S)

Severity and extent of adhesion formation assessed using a multidimensional adhesion scoring system.

RESULT(S)

Significantly fewer postsurgical adhesions were seen after treatment with Adept, Hyalobarrier Gel, Interceed, PDLA membrane, and phospholipid emulsion than after Ringer's lactate solution. Severe, clinically relevant adhesions were not observed after Hyalobarrier Gel and in only one animal after Adept.

CONCLUSION(S)

Both solid and liquid barriers can prevent adhesions. Hydroflotation formulas, such as Adept and Hyalobarrier Gel, avoid suture-induced adhesions, are easy to use, and their protective effects are evenly distributed. They are suitable for adhesion prevention after multifocal trauma in rats, and require further testing in the everyday clinical situation.

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.