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

Effect of hyaluronate-based bioresorbable membrane (Seprafilm) on outcomes of abdominal surgery: a meta-analysis and trial sequential analysis of randomised controlled trials

We aimed to evaluate comparative outcomes of abdominal surgery with and without hyaluronate-based bioresorbable membrane (Seprafilm).We conducted a systematic search of electronic databases and bibliographic reference lists with application of a combination of free text and controlled vocabulary search adapted to thesaurus headings, search operators and limits. Small bowel obstruction, anastomotic leak, surgical site infections, ileus, and severity of adhesions were the evaluated outcome measures. Thirteen randomised controlled trials reporting a total of 3665 patients evaluating outcomes of abdominal surgeries with (n = 1800) or without (n = 1865) use of Seprafilm were identified. Use of Seprafilm was associated with significantly lower risk of small bowel obstruction (RR 0.53, 95% CI 0.38-0.73, P = 0.0001) but significantly higher rate of anastomotic leak (RR 1.85, 95% CI 1.15-3.00 P = 0.01). Moreover, while Seprafilm resulted in significantly more adhesions-free patients (RR 5.57, 95% CI 3.37-9.19, P < 0.0001) compared to no Seprafilm, its use was associated with significantly lower grade 2 (RR 0.57, 95% CI 0.35-0.95, P = 0.003) or 3 (RR 0.31, 95% CI 0.17-0.55, P < 0.0001) adhesions. There was no significant difference in surgical site infection (RR: 1.21, 95 CI 0.86-1.70, P = 0.28), intra-abdominal abscess (RR 1.46, 95 CI 0.92-2.32, P = 0.11) or paralytic ileus (RR 0.97, 95 CI 0.68-1.38, P = 0.87) between two groups. The trial sequential analysis demonstrated that the meta-analysis findings are conclusive. Our meta-analysis demonstrated that Seprafilm reduces the risk of small bowel obstruction and severity of adhesions after abdominal surgery. However, it may increase the risk of anastomotic leak. We recommend use of Seprafilm in any abdominal surgery which does not involve an anastomosis.

Adhesion barriers and topical hemostatic agents are risk factors for post-cesarean section infections

BACKGROUND

Cesarean sections are the most common surgery worldwide, and post-cesarean section infections and hemorrhage are a major cause for morbidity and mortality. In recent years, many surgeons use adhesion barriers as well as hemostatic agents during primary and repeated cesarean section. The data regarding the safety of these agents is relatively limited. The objective of this study was to investigate whether the use of adhesion barriers and topical hemostatic agents pose a risk for post-cesarean section infections.

METHOD

A case-control study composed of women who were admitted to the Soroka University Medical Center between the years 2012 and 2016 was conducted. The study group was composed of women admitted owing to post-cesarean section infections (cases) and those who underwent cesarean sections without post-cesarean section infection (control subjects). Matching was done according to date and surgery setting (elective versus emergency). A univariate analysis was followed by a multiple regression model in order to examine the association between adhesion barriers/hemostatic agents and post-cesarean section infections.

RESULTS

During the study period, 113 patients developed postoperative infection (cases); 71.7% were diagnosed with surgical site infection, 7.1% with endometritis, and 21.2% with other infections. These were compared with 226 control subjects. In the univariate analysis, the use of adhesion barriers/hemostatic agents were found to be associated with post-cesarean section infection. Using a multivariable analysis controlling for previous cesarean section, skin closer technique, preterm delivery, and duration of surgery >60 minutes, the use of adhesion barriers as well as hemostatic agents was found to be independently associated with post-cesarean section infection (adjusted odds ratio = 2.11, 95% confidence interval = 1.17-3.84; adjusted odds ratio = 2.29, 95% confidence interval = 1.37-3.8, respectively) CONCLUSION: Adhesion barriers and hemostatic agents were found to be independently associated with post-cesarean section infections. Further larger studies are needed to reinforce our findings. The use of these materials should be carefully considered, and their cost-effectiveness re-examined.

Cell barrier function of resident peritoneal macrophages in post-operative adhesions

Post-operative adhesions are a leading cause of abdominal surgery-associated morbidity. Exposed fibrin clots on the damaged peritoneum, in which the mesothelial barrier is disrupted, readily adhere to surrounding tissues, resulting in adhesion formation. Here we show that resident F4/80^HighCD206⁻ peritoneal macrophages promptly accumulate on the lesion and form a ‘macrophage barrier’ to shield fibrin clots in place of the lost mesothelium in mice. Depletion of this macrophage subset or blockage of CD11b impairs the macrophage barrier and exacerbates adhesions. The macrophage barrier is usually insufficient to fully preclude the adhesion formation; however, it could be augmented by IL-4-based treatment or adoptive transfer of this macrophage subset, resulting in robust prevention of adhesions. By contrast, monocyte-derived recruited peritoneal macrophages are not involved in the macrophage barrier. These results highlight a previously unidentified cell barrier function of a specific macrophage subset, also proposing an innovative approach to prevent post-operative adhesions.

Peritoneal adhesions are a major cause of complications after abdominal surgery. Here the authors use a post-operative abdominal adhesion model in mice to show that resident F4/80^HighCD206⁻ macrophages form a protective barrier that can be enhanced by IL-4 administration or adoptive transfer of these cells.

Antibacterial, hemostasis, adhesive, self-healing polysaccharides-based composite hydrogel wound dressing for the prevention and treatment of postoperative adhesion

Herein, we fabricated novel self-healing, in situ injectable, biodegradable, and non-toxic hydrogels anti-adhesion barrier materials composed of N, O-carboxymethyl chitosan (N,O-CS) and oxidized dextran (ODA) without requiring any chemical cross-linking agent or external stimuli triggers for the prevention and treatment of post-operative peritoneal adhesions. The N,O-CS/ODA hydrogels have a good suitable gelation time, good cytocompatibility and hemocompatibility, good antibacterial activity, excellent biodegradable and biocompatible, and can effectively inhibit the adhesion of fibroblasts to the wound, thereby suggesting that N,O-CS/ODA hydrogels are suitable for preventing post-operative adhesion. Meanwhile, a rat injury sidewall-cecum abrasion model is developed to investigate the efficacy of these hydrogels in achieving post-operative anti-adhesion. A significant reduction of peritoneal adhesions (10% rat with lower score adhesion) is observed in the N,O-CS/ODA-hydrogel-treated group compared with the commercial hydrogel and control groups. These results demonstrated that N,O-CS/ODA hydrogel could effectively prevent post-operative peritoneal adhesion without side effects. Therefore, the N,O-CS/ODA hydrogels with multi-functional properties exhibit great potential for the prevention and treatment of postoperative adhesion.

Patient-Reported Quality of Life Following Laparotomy in a Resource-Limited Setting

INTRODUCTION

The burden of surgical diseases is high in sub-Saharan Africa. Despite limitations to surgical care access, health-related quality of life (HRQoL) data following surgical intervention are scarce.

METHODS

We performed a 3-month prospective observational study of adult patients undergoing an abdominal operation. We administered the Patient-Reported Outcome Measurement Information System (PROMIS)-25 and Index of Independence in Activities of Daily Living questionnaire preoperatively (to postoperative day [POD] #1), POD#7, and POD#30. PROMIS-25 HRQoL domains were measured and converted to standardized T-scores (median 50, minimal important clinical difference 3).

RESULTS

Of the 117 laparotomy patients who were enrolled, 89 (76.1%) were male with a median age of 39 years (IQR 27-54). Operations were primarily for intestinal volvulus (n = 30, 28.3%) and intestinal perforation (n = 29, 27.4%). We completed a total of 80 (68.4%), 95 (81.2%), and 77 (65.8%) surveys preoperatively, at POD#7, and POD#30, respectively. Preoperatively patients showed high median levels of anxiety (56), depression (60), fatigue (63), and pain interference (62), which all improved postoperatively. Mobility was poor preoperatively (31) and showed improvement during recovery but remained poor [POD#7: 32, POD#30: 39]. Pain intensity was high (10/10) preoperatively and improved to 3/10 by POD#30. Patients with complications compared to those without had clinically significant worse HRQoL in all domains measured by POD#30.

DISCUSSION

Abdominal surgery patients in a resource-limited setting present with poor HRQoL, which improves postoperatively. Mobility remained poor throughout follow-up despite improved pain scores. Our findings highlight the need for improved HRQoL and pain control among surgical patients.

Anti-Adhesive Effect of Porous Polylactide Film in Rats

Excessive adhesion between tissues on a significant area can cause the development of disorders, cosmetic problems, and ileus. Methods for preventing adhesion include the use of drugs and anti-adhesion barriers for physical blocking. In this study, the adhesion prevention effect of polylactide film in porous form was analyzed. A porous polylactide film was manufactured using a molecular weight of at least 100,000. To generate porosity, 98% methylene chloride and 95% ethyl alcohol were used as solvents. The thickness, surface, and internal pore shape of film were investigated. The crystal structures and melting temperature of film were measured. In the rat model, the presence and severity of adhesion were then analyzed. The thickness of the film ranged from 10 to 20 µm. The surface of the film contained pores with diameters of less than 10 µm. Partial crystallinity appeared from 15° to 20°, but the structure was amorphous overall. In the rat cecum abrasion model, adhesion occurred in 3 of the 13 rats in the polylactide experimental group, representing a 23.1% incidence rate. There were statistically significant differences in the severity of adhesion. The use of porous polylactide films can reduce the incidence of adhesion.

Biodegradable Zwitterionic Cream Gel for Effective Prevention of Postoperative Adhesion

Postoperative peritoneal adhesions were frequent complications for almost any types of abdominal and pelvic surgery. This led to numerous medical problems and huge financial burden to the patients. Current anti-adhesion strategies focused mostly on physical barriers including films and hydrogels. However, they can only alleviate or reduce adhesions to certain level and their applying processes were far from ideal. This work reported the development of a biodegradable zwitterionic cream gel presenting a series of characters for an idea anti-adhesion material, including unique injectable yet malleable and self-supporting properties, which enabled an instant topical application, no curing, waiting or suturing, no hemostasis requirement, protein/cell resistance and biodegradability. The cream gel showed a major advancement in anti-adhesion efficacy by completely and reliably preventing a primary and a more severe recurrent adhesion in rat models.

Effectiveness of barrier agents for preventing postoperative bowel obstruction after laparoscopic surgery: a retrospective cohort study

PURPOSE

The effectiveness of using anti-adhesion agents in laparoscopic surgery is controversial. We compared the outcomes of patients exposed to anti-adhesion agents (barrier group) with those of patients not exposed (no barrier group) in laparoscopic surgery.

METHODS

Using a nationwide claim-based database in Japan, we analyzed data from patients who underwent laparoscopic surgery between 2005 and 2019 and compared the patient characteristics and the proportion of those with bowel obstruction between the barrier and no barrier groups. We also performed several sensitivity and subgroup analyses.

RESULTS

Of the 57,499 patients who met the inclusion criteria, 14,360 and 43,139 were assigned to the barrier and no barrier groups, respectively. The proportion of patients with a bowel obstruction in the two groups did not differ among all patients hospitalized for obstruction (1.1 vs. 1.1%, p = 0.63) and those requiring surgery (0.2 vs. 0.2%, p = 0.39). In the sensitivity analysis with propensity score matching, the incidences of bowel obstruction between the barrier and non-barrier groups were equivocal (1.3 vs. 1.6%), but statistically marginal (chi-square test, p = 0.035; log-rank test, p = 0.09).

CONCLUSION

The use of barrier agents for adhesive prevention did not show clear effectiveness for the prevention of bowel obstruction after laparoscopic surgery for unselected cases. Further studies focusing on more specific procedures are needed.

Experimental evaluation of icodextrin delivery as pressurized aerosol (PIPAC): Antiadhesive and cytotoxic effects

BACKGROUND

Icodextrin (IDX) is an antiadhesive polymer that can be used as a carrier solution for intraperitoneal (IP) delivery of chemotherapeutic drugs.

METHODS

We investigated the suitability of IDX solution as a carrier of Cisplatin and Doxorubicin for delivery as pressurized intraperitoneal aerosol chemotherapy (PIPAC). We examined the sprayability of IDX, the aerosol characteristics, the stability of the molecule after aerosolization, the effects of IDX on the adhesion of MKN45 human gastric cancer cells, the synergistic effect of aerosolized IDX with Cisplatin and Doxorubicin, and the chemical stability of IDX, Cisplatin, and Doxorubicin in combination.

RESULTS

Delivery of IDX as PIPAC is feasible with no particular restrictions. The median droplet size of 35.7 μm did not change at increasing concentrations. IDX withstood the shear forces applied by the nebulizer and remained stable after aerosolization (ANOVA, p = 0.97). IDX did not impair the cytotoxic effects of Cisplatin and Doxorubicin (ns). IDX had a significant antiadhesive impact alone (p < 0.03) and in combination with Cisplatin and Doxorubicin (p < 0.02). IDX as a carrier for Cisplatin and Doxorubicin remained stable at 4 °C for three months and did not cause degradation of those two substances.

CONCLUSION

The proposed combination takes advantage of the antiadhesive properties of IDX, the cytotoxic effect of Cisplatin and Doxorubicin, and an advanced drug delivery system.

Cesarean delivery: an evidence-based review of the technique

The cesarean section is utilized to deliver babies since the late 19^th century. Nowadays, the frequency of cesarean section is increased, mainly because of the low rate of complications and for the increasing demand from future mothers, scared by the idea of painful labor. Although the technique to perform cesarean section has been refined over time, infections, hemorrhage, pain and other consequences still represent matter of debate. To try to reduce the incidence of these complications many trials, randomized or not, have been performed, with the aim to analyze different technical aspects of this surgery. The aim of our review was to resume all the evidence-based instructions on how to best approach to cesarean section practice, in a step-to-step fashion, considering pre-operative actions, opening and closing steps, and postoperative prophylaxis.

Efficacy and safety of Seprafilm for preventing intestinal obstruction after gastrointestinal neoplasms surgery: a systematic review and meta-analysis

OBJECTIVE

It was controversial that hyaluronate-carboxy-methylcellulose-based membrane (Seprafilm) could prevent intestinal obstruction after gastrointestinal neoplasms operation. This study aimed to evaluate the efficacy and safety of Seprafilm in preventing postoperative intestinal obstruction of gastrointestinal neoplasms patients.

METHODS

A systematic research of multiple databases was performed to identify relevant studies, and the studies satisfying the inclusion criteria were included. Risk ratio (RR), weighted mean difference (WMD), and 95% confidence intervals were calculated using RevMan 5.3.

RESULTS

2937 patients from 10 studies who were enrolled in this meta-analysis were divided into the Seprafilm group (n = 1334) and the control group (n = 1603). The Seprafilm group had lower incidence of intestinal obstruction (RR, 0.52; 95% CI, 0.38-0.70; p < .0001), reoperation rates due to intestinal obstruction (RR, 0.48; 95% CI, 0.28 - 0.80; p = .005), incidence of overall complications (RR, 0.77; 95% CI, 0.61-0.97; p = .03) and higher serum creatinine on postoperative day 5 (WMD, 0.15; 95% CI, 0.05-0.25; p = .003). There were no differences regarding time to intestinal obstruction after operation, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, white blood cell count results on day 5 and 7, serum creatinine on day 7, hospital stay, and incidence of intra-abdominal infection, wound infection, anastomotic leakage between the 2 groups.

CONCLUSIONS

This meta-analysis provided valuable evidence-based support for the efficacy and safety of Seprafilm in preventing postoperative intestinal obstruction of gastrointestinal neoplasms patients. However, more multicenter randomized controlled trials from different countries are needed.

Adhesive Small Bowel Obstruction and the six w's: Who, How, Why, When, What, and Where to diagnose and operate?

BACKGROUND AND AIMS

Approximately 75% of patients admitted with small bowel obstruction have intra-abdominal adhesions as their cause (adhesive small bowel obstruction). Up to 70% of adhesive small bowel obstruction cases, in the absence of strangulation and bowel ischemia, can be successfully treated with conservative management. However, emerging evidence shows that surgery performed early during the first episode of adhesive small bowel obstruction is highly effective. The objective of this narrative review is to summarize the current evidence on adhesive small bowel obstruction management strategies.

MATERIALS AND METHODS

A review of the literature published over the last 20 years was performed to assess Who, hoW, Why, When, What, and Where diagnose and operate on patients with adhesive small bowel obstruction.

RESULTS

Adequate patient selection through physical examination and computed tomography is the key factor of the entire management strategy, as failure to detect patients with strangulated adhesive small bowel obstruction and bowel ischemia is associated with significant morbidity and mortality. The indication for surgical exploration is usually defined as a failure to pass contrast into the ascending colon within 8-24 h. However, operative management with early adhesiolysis, defined as operative intervention on either the calendar day of admission or the calendar day after admission, has recently shown to be associated with an overall long-term survival benefit compared to conservative management. Regarding the surgical technique, laparoscopy should be used only in selected patients with an anticipated single obstructing band, and there should be a low threshold for conversion to an open procedure in cases of high risk of bowel injuries.

CONCLUSION

Although most adhesive small bowel obstruction patients without suspicion of bowel strangulation or gangrene are currently managed nonoperatively, the long-term outcomes following this approach need to be analyzed in a more exhaustive way, as surgery performed early during the first episode of adhesive small bowel obstruction has shown to be highly effective, with a lower rate of recurrence.

Intraoperative maneuvers may affect the development of early postoperative small bowel obstruction after laparoscopic colorectal cancer surgery: Multicenter prospective cohort study

BACKGROUND

Early postoperative small bowel obstruction (EPSBO) is one of the most common complications after colorectal cancer (CRC) surgery, and clarification of its causes is desired. Several reports have demonstrated the risks of EPSBO, but few have focused on laparoscopic surgery for CRC and intraoperative maneuvers. We therefore prospectively examined the risk factors for EPSBO after laparoscopic CRC resection.

METHODS

We prospectively enrolled 706 patients with CRC that underwent laparoscopic CRC resection in our hospital and affiliated hospitals. We analyzed several factors concerning EPSBO including intraoperative procedures.

RESULTS

EPSBO developed in 43 of the 706 cases (6.1%). Univariate analysis showed that risk factors for EPSBO were male sex, increased operative time, repositioning of the small intestine before wound closure and anastomotic leakage. Risk factors for EPSBO according to multivariate analysis were increased operative time (odds ratio (OR) 2.41; P = 0.032), repositioning of the small intestine before wound closure (OR 3.58; P = 0.005) and anastomotic leakage (OR 3.91; P = 0.006).

CONCLUSION

To reduce EPSBO after laparoscopic CRC surgery, the operation should be finished as soon as possible without performing optional maneuvers. To avoid development to EPSBO, particular care is required in cases where the risk of anastomotic leakage is predicted to be high.

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.

Prevention of adhesions post-abdominal surgery: Assessing the safety and efficacy of Chitogel with Deferiprone in a rat model

Introduction

Adhesions are often considered to be an inevitable consequence of abdominal and pelvic surgery, jeopardizing the medium and long-term success of these procedures. Numerous strategies have been tested to reduce adhesion formation, however, to date, no surgical or medical therapeutic approaches have been successful in its prevention. This study demonstrates the safety and efficacy of Chitogel with Deferiprone and/or antibacterial Gallium Protoporphyrin in different concentrations in preventing adhesion formation after abdominal surgery.

Materials and methods

112 adult (8–10 week old) male Wistar albino rats were subjected to midline laparotomy and caecal abrasion, with 48 rats having an additional enterotomy and suturing. Kaolin (0.005g/ml) was applied to further accelerate adhesion formation. The abrasion model rats were randomized to receive saline, Chitogel, or Chitogel plus Deferiprone (5, 10 or 20 mM), together with Gallium Protoporphyrin (250μg/mL). The abrasion with enterotomy rats were randomised to receive saline, Chitogel or Chitogel with Deferiprone (1 or 5 mM). At day 21, rats were euthanised, and adhesions graded macroscopically and microscopically; the tensile strength of the repaired caecum was determined by an investigator blinded to the treatment groups.

Results

Chitogel with Deferiprone 5 mM significantly reduced adhesion formation (p<0.01) when pathologically assessed in a rat abrasion model. Chitogel with Deferiprone 5 mM and 1 mM also significantly reduced adhesions (p<0.05) after abrasion with enterotomy. Def-Chitogel 1mM treatment did not weaken the enterotomy site with treated sites having significantly better tensile strength compared to control saline treated enterotomy rats.

Conclusions

Chitogel with Deferiprone 1 mM constitutes an effective preventative anti-adhesion barrier after abdominal surgery in a rat model. Moreover, this therapeutic combination of agents is safe and does not weaken the healing of the sutured enterotomy site.

Adhesion barriers in laparoscopic myomectomy: Evidence from randomized clinical trials

OBJECTIVE

To evaluate the effectiveness of different adhesion barriers in the prevention of de novo adhesion development after laparoscopic myomectomy.

METHODS

A systematic review was performed by searching seven electronic databases for all randomized clinical trials (RCTs) comparing the use of any absorbable adhesion barrier (i.e. intervention group) with either no treatment or placebo (i.e. control group) in the prevention of adhesion development after laparoscopic myomectomy.

RESULTS

Eight RCTs with a total of 748 participants (392 in the intervention group and 356 in the control group) were included. The assessed adhesion barrier methods were: oxidized regenerated cellulose (ORC) in two studies, auto-crosslinked hyaluronic acid (HA) gel in two studies, 4% icodextrin solution in one study, modified HA and carboxy-methylcellulose in one study, polyethylene glycol ester trilysine amine solution plus a borate buffer solution in one study, and polyethylene glycol amine plus dextran aldehyde polymers in another study.

CONCLUSION

Adhesion barrier methods showing the most promising results were: ORC, auto-crosslinked HA gel, and polyethylene glycol amine plus dextran aldehyde polymers.

Fouling-resistant zwitterionic polymers for complete prevention of postoperative adhesion

Postoperative adhesions are most common issues for almost any types of abdominal and pelvic surgery, leading to adverse consequences. Pharmacological treatments and physical barrier devices are two main approaches to address postoperative adhesions but can only alleviate or reduce adhesions to some extent. There is an urgent need for a reliable approach to completely prevent postoperative adhesions and to significantly improve the clinical outcomes, which, however, is unmet with current technologies. Here we report that by applying a viscous, cream-like yet injectable zwitterionic polymer solution to the traumatized surface, postoperative adhesion was completely and reliably prevented in three clinically relevant but increasingly challenging models in rats. The success rate of full prevention is over 93% among 42 animals tested, which is a major leap in antiadhesion performance. Clinically used Interceed film can hardly prevent the adhesion in any of these models. Unlike current antiadhesion materials serving solely as physical barriers, the "nonfouling" zwitterionic polymer functioned as a protective layer for antiadhesion applications with the inherent benefit of resisting protein/cell adhesions. The nonfouling nature of the polymer prevented the absorption of fibronectins and fibroblasts, which contribute to the initial and late-stage development of the adhesion, respectively. This is the key working mechanism that differentiated our "complete prevention" approach from current underperforming antiadhesion materials. This work implies a safe, effective, and convenient way to fully prevent postoperative adhesions suffered by current surgical patients.

Enhancing delivery of small molecule and cell-based therapies for ovarian cancer using advanced delivery strategies

Ovarian cancer is the most lethal gynecological malignancy with a global five-year survival rate of 30-50%. First-line treatment involves cytoreductive surgery and administration of platinum-based small molecules and paclitaxel. These therapies were traditionally administered via intravenous infusion, although intraperitoneal delivery has also been investigated. Initial clinical trials of intraperitoneal administration for ovarian cancer indicated significant improvements in overall survival compared to intravenous delivery, but this result is not consistent across all studies performed. Recently cell-based immunotherapy has been of interest for ovarian cancer. Direct intraperitoneal delivery of cell-based immunotherapies might prompt local immunoregulatory mechanisms to act synergistically with the delivered immunotherapy. Based on this theory, pre-clinical in vivo studies have delivered these cell-based immunotherapies via the intraperitoneal route, with promising results. However, successful intraperitoneal delivery of cell-based immunotherapy and clinical adoption of this technique will depend on overcoming challenges of intraperitoneal delivery and finding the optimal combinations of dose, therapeutic and delivery route. We review the potential advantages and disadvantages of intraperitoneal delivery of cell-based immunotherapy for ovarian cancer and the pre-clinical and clinical work performed so far. Potential advanced delivery strategies, which might improve the efficacy and adoption of intraperitoneal delivery of therapy for ovarian cancer, are also outlined.

Evaluation of adhesion barrier types in a rat hepatectomy-induced adhesion model

Background

Adhesion formation after hepatectomy creates problems for repeat hepatectomy. This study aimed to compare the effectiveness of a spray (AdSpray) and sheet adhesion barrier (Seprafilm) in a rat hepatectomy-induced adhesion model.

Methods

Thirty male Sprague-Dawley rats underwent partial resection of the left lateral liver lobe. They were randomly assigned to control (n = 10), AdSpray (n = 10), and Seprafilm groups. Seven days after surgery, the animals were sacrificed, and adhesions at the hepatic resection surface were blindly evaluated.

Results

In the control group, adhesions were formed in all 10 animals (100%), with a 69% adhesion extent (mean). In the AdSpray group, the incidence of adhesions (40%) and the adhesion extent (mean, 10%) were significantly lower than in the control group (incidence; p = 0.0147, adhesion extent; p = 0.0007). In the Seprafilm group, the incidence of adhesions was 70%. The adhesion extent of Seprafilm (mean, 30%) was significantly lower than in the control group (p = 0.0492). No significant differences were observed between the AdSpray and Seprafilm groups. As for histopathological examination, animals in the AdSpray group showed a similar healing profile to that of the control group without delayed healing and regeneration of mesothelial cells. In contrast, the Seprafilm group showed ongoing foreign body reaction to Seprafilm, and regeneration of mesothelial cells was immature at 7 days.

Conclusions

Both the spray-type gel and sheet adhesion barriers significantly reduced adhesion formation after hepatectomy. The spray-type adhesion barrier caused no adverse events and induced favorable healing. These adhesion barriers may be effective in hepatectomy. Further animal studies and clinical trials are required to determine their benefits in clinical use.

Mesenchymal stem cells - a promising strategy for treating knee osteoarthritis

AIMS

The purpose of our study was to determine whether mesenchymal stem cells (MSCs) are an effective and safe therapeutic agent for the treatment of knee osteoarthritis (OA), owing to their cartilage regeneration potential.

METHODS

We searched PubMed, Embase, and the Cochrane Library, with keywords including "knee osteoarthritis" and "mesenchymal stem cells", up to June 2019. We selected randomized controlled trials (RCTs) that explored the use of MSCs to treat knee OA. The visual analogue scale (VAS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC), adverse events, and the whole-organ MRI score (WORMS) were used as the primary evaluation tools in the studies. Our meta-analysis included a subgroup analysis of cell dose and cell source.

RESULTS

Seven trials evaluating 256 patients were included in the meta-analysis. MSC treatment significantly improved the VAS (mean difference (MD), -13.24; 95% confidence intervals (CIs) -23.28 to -3.20, p = 0.010) and WOMAC (MD, -7.22; 95% CI -12.97 to -1.47, p = 0.010). The low-dose group with less than 30 million cells showed lower p-values for both the VAS and WOMAC. Adipose and umbilical cord-derived stem cells also had lower p-values for pain scores than those derived from bone marrow.

CONCLUSION

Overall, MSC-based cell therapy is a relatively safe treatment that holds great potential for OA, evidenced by a positive effect on pain and knee function. Using low-dose (25 million) and adipose-derived stem cells is likely to achieve better results, but further research is needed. Cite this article: Bone Joint Res 2020;9(10):719-728.

Prevention of intra-abdominal adhesions by a hyaluronic acid gel; an experimental study in rats

BACKGROUND

In 80% to 90% of the patients intra-abdominal adhesions occur after abdominal surgery, which can cause small-bowel obstruction, chronic abdominal pain, female infertility and difficulty during reoperation. A novel crosslinked hyaluronic acid gel is evaluated regarding its anti-adhesive capacities in an ischemic button model in rats.

METHOD

51 adult, male Wistar rats from a registered breeder, received eight ischemic buttons each and were treated with hyaluronic acid gel (HA, HyaRegen^©), hyaluronic acid carboxymethylcellulose (HA-CMC, Seprafilm^©) or no anti-adhesive barrier. After 14 days, the animals were sacrificed and adhesions were scored macroscopically. The number of buttons and organs involved in adhesions were recorded. Per animal, one button with adhesions and one without adhesions was explanted for qPCR analysis. Mann-Whitney U, Fisher's exact and Wilcoxon signed rank test were used for data analysis. A p-value of 0.05 was considered significant.

RESULTS

Macroscopic evaluation of adhesion formation did not differ between the groups. The number of organs involved in adhesions in the HA gel group was significantly lower compared to HA-CMC (p = .041) and the control group (p = .012). A significantly, 1.36-fold higher clec10a (p = 0.25), 1.80-fold higher cd163 (p = 0.003) and 5.14-fold higher mmp1 expression (p = 0.028) was found in ischemic buttons with adhesions compared to buttons without adhesions.

CONCLUSION

HA gel application reduces the number of organs involved in adhesions in an ischemic button model, but no overall reduction in adhesion formation was encountered. Macrophage subtype 2 polarization and high mmp1 expression are associated with adhesion formation. Further investigation is needed in the exact pathophysiologic process of adhesion formation and the role of macrophage polarization.

H-Bonding Supramolecular Hydrogels with Promising Mechanical Strength and Shape Memory Properties for Postoperative Antiadhesion Application

Development of a physical barrier with mechanical properties similar to human smooth muscle and an on-demand degradation profile is crucial for the clinical prevention of postoperative adhesion. Herein, a series of supramolecular hydrogels (PMI hydrogels) composed of poly(ethylene glycol) (PEG), methylenediphenyl 4, 4-diisocyanate (MDI), and imidazolidinyl urea (IU, hydrogen bonding reinforced factor) with biodegradability and high toughness are reported to serve as physical barriers for abdominal adhesion prevention. The tensile fracture strength and strain of the PMI hydrogels could be adjusted in the ranges of 0.6-2.3 MPa and 100-440%, respectively, and their Young's moduli (0.2-1.6 MPa) are close to that of human soft tissues like smooth muscle and skin tissue as well as they have outstanding shape memory properties. The PMI hydrogels show good cell and tissue biocompatibility, and the in vivo retention time is in accord with the needs for the postoperative antiadhesion physical barriers. Through an abdominal defect model on mice, this study shows that the PMI hydrogel can completely prevent tissue adhesion compared to the commercialized Seprafilm with high safety. Owing to the promising mechanical properties and good biocompatibility, the PMI hydrogels may be extended for various biomedical applications and the development of advanced flexible electronic devices.

Bowel surgery for endometriosis: A practical look at short- and long-term complications

Endometriosis involving the bowel requires a thorough evaluation prior to deciding upon surgical treatment. Patient symptoms, treatment goals, extent and location of disease, surgeon experience, and anticipated risks all play a part in the preoperative decision-making process. Short- and long-term complications after bowel surgery for endometriosis are the focus of this article. Unfortunately, the literature to date has inherent limitations that prevent generalizability. Most studies are retrospective or prospective single-center case series. Publication bias is unavoidable with mainly large volume experts sharing their experience. As a result, there is a need for high-quality prospective studies that standardize inclusion criteria and outcome measures among various centers with an aim to present long-term outcomes. In the meantime, care for those with endometriosis involving the bowel requires a thorough preoperative plan to minimize risks and a need for early diagnosis and management of complications unique to bowel surgery.

Clinical adhesion score (CLAS): development of a novel clinical score for adhesion-related complications in abdominal and pelvic surgery

Background

Adhesions are a major cause of long-term postsurgical complications in abdominal and pelvic surgery. Existing adhesion scores primarily measure morphological characteristics of adhesions that do not necessarily correlate with morbidity. The aim of this study was to develop a clinical adhesion score (CLAS) measuring overall clinical morbidity of adhesion-related complications in abdominal and pelvic surgery.

Methods

An international Delphi study was performed to identify relevant score items for adhesion-related complications, including small bowel obstruction, female infertility, chronic abdominal or pelvic pain, and difficulties at reoperation. The CLAS includes clinical outcomes, related to morbidity of adhesions, and weight factors, to correct the outcome scores for the likelihood that symptoms are truly caused by adhesions. In a pilot study, two independent researchers retrospectively scored the CLAS in 51 patients to evaluate inter-observer reliability, by calculating the Intraclass correlation coefficient. During a feasibility assessment, we evaluated whether the CLAS completely covered different clinical scenarios of adhesion-related morbidity.

Results

Three Delphi rounds were performed. 43 experts agreed to participate, 38(88%) completed the first round, and 32 (74%) the third round. Consensus was reached on 83.4% of items. Inter-observer reliability for the CLAS was 0.95 (95% CI 0.91–0.97). During feasibility assessment, six items were included. As a result, the CLAS includes 22 outcomes and 23 weight factors.

Conclusion

The CLAS represents a promising scoring system to measure and monitor the clinical morbidity of adhesion-related complications. Further studies are needed to confirm its utility in clinical practice.

Electronic supplementary material

The online version of this article (10.1007/s00464-020-07621-5) contains supplementary material, which is available to authorized users.

Surgical adhesions among women undergoing laparoscopic gynecological surgery with or without adhesiolysis - prevalence, severity, and implications: retrospective cohort study at a University Hospital

Objective:

To find out the prevalence of adhesions, severity, and their relation to the current clinical scenario and to the type of previous surgery.

Methods and Materials:

A retrospective study of patients who already had different previous abdominopelvic surgery and subsequently underwent gynecological laparoscopic surgery for various indications. The patients’ clinical and operative notes were reviewed and analyzed.

Results:

There were 654 procedures performed. The most common indication for the laparoscopic surgery was secondary infertility 23.5%, followed by adnexal lesions 22.0% and primary infertility 19.6%. Intraoperative adhesions were found in 45.3%. Adhesions were deemed relevant to the clinical scenario in 21.3%. Patients who had a previous history of open (traditional) surgery were more likely to be found with adhesions in comparison with patients with history of laparoscopic surgery (odds ratio: 2.7, 95% confidence interval: 1.4–5.3, p = 0.0025). The presence of adhesions was found to be strongly associated with previous abdominopelvic surgery than non-abdominopelvic surgery (odds ratio: 4.3, p = 0.0078, 95% confidence interval: 1.5–12.5). The most common location of the adhesions was abdominal (36.1%), mixed abdominal and pelvic (35.1%), and pelvic adhesions (28.1%). Severe adhesions were found in 36.1%; 13.6% of converted laparoscopy to open surgery was due to adhesions. Cesarean sections were significantly associated with adhesions. Patients who had cesarean sections were more likely to have adhesions than those who had not (odds ratio: 5.7, 95% confidence interval: 3.8–8.6, p < 0.0001). Adhesiolysis was done without complications in 19.6% of patients with adhesions.

Conclusion:

Adhesions were prevalent in gynecological patients with previous abdominopelvic surgery. They were a significant contributor to the gynecological and reproductive issues. To minimize the risk of postoperative adhesions, laparoscopic approach should be encouraged instead of traditional surgery and rates of cesarean section should be reduced. Further high-quality studies are needed to establish conclusion and practical guidance toward the use of adhesion barriers.

Application of Traditional Chinese Medicines in Postoperative Abdominal Adhesion

Adhesion is a frequent complication after abdominal surgery. Although various methods have been applied to prevent and treat postoperative abdominal adhesion (PAA), few modern drugs designed for clinical applications have reached the expected preventive or therapeutic effect so far. There is an imperative to develop some new strategies for the treatment of PAA. Traditional Chinese medicine (TCM) has been widely practiced for thousands of years and played an indispensable role in the prevention and treatment of diseases. Modern medicine researchers have accepted the therapeutic effects of many active components derived from Chinese medicinal herbs. The review stresses the most commonly used TCM treatment, including Chinese medicinal herbals and monomers, TCM formulas, and acupuncture treatment.

The novel mechanism of valproate to prevent peritoneal adhesion formation

PURPOSE

A novel pharmacological mechanism of valproate was analyzed using a hamster model of adhesion.

METHODS

Valproate or placebo was administered just after cecal injury and adhesion severity scores and histological were analyzed.

RESULTS

The adhesion severity scores in the placebo- and valproate-treated groups were 2.67 ± 0.42 and 1.0 ± 0.37, respectively, with a significant difference between the groups. A significant increase in mast cell numbers was observed in the placebo-treated group vs. the sham-operated group; however, the mast cell number in the adhesive lesion was significantly lower in the valproate-treated group than in the placebo-treated group. The number of cells positive for chymase, an enzyme in mast cells, in the adhesive lesion was significantly higher in the placebo-treated group, but its increase was attenuated significantly by treatment with valproate. The myeloperoxidase gene expression level in the cecum was significantly higher in the placebo-treated group than in the sham-operated group, but there was no significant difference in the myeloperoxidase gene expression level between the sham-operated and valproate-treated groups in. In an in vitro experiment, valproate inhibited purified human and hamster chymases dose-dependently.

CONCLUSION

The chymase inhibitory effect of valproate may contribute to prevent adhesion formation after abdominal injury.

Platelet-rich fibrin prevents postoperative intestinal adhesion

Platelet-rich fibrin (PRF) was prepared from the blood of BALB/C inbred mice to explore potential effects on postoperative intestinal adhesion. A murine model of intestinal adhesion characterized by abdominal wall defect/and cecum damage was established by scraping caecum serosa and cutting peritoneum and muscles in the abdominal wall. The wound was covered with PRF (group A), sodium hyaluronate (group B), or left alone (blank control; group C). All animals were monitored for 28 days. The incidence of adhesion was 35.0, 66.7, and 73.7% in groups A, B, and C, respectively. The incidence of adhesion in group A was significantly lower than that in group C (p < .05). Histopathologically, severity of fibrosis and the number of fibroblasts or inflammatory cells in group A were lower than those in groups B and C (p < .05), whereas the number of mesothelial cells was higher (p = .001). Furthermore, the severity of fibrosis and number of fibroblasts or inflammatory cells were lower in low grade than those in high grade of adhesion (p < .05), whereas the number of mesothelial cells was higher (p < .05). Collectively, PRF applied to abdominal surgery may reduce the incidence of intestinal adhesion by promoting proliferation of mesothelial cells whereas inhibiting proliferation of fibroblasts and infiltration of inflammatory cells.

Identification of candidate biomarkers correlated with pathogenesis of postoperative peritoneal adhesion by using microarray analysis

BACKGROUND

Postoperative peritoneal adhesion (PPA), characterized by abdominal pain, female infertility, and even bowel obstruction after surgery, has always been a major concern. The occurrence and formation of adhesion are from complex biological processes. However, the molecular mechanisms underlying the basis of microarray data profile, followed by peritoneal adhesion formation, are largely unknown.

AIM

To reveal the underlying pathogenesis of PPA at the molecular level.

METHODS

The gene expression profile was retrieved from the Gene Expression Omnibus database for our analysis. We identified a panel of key genes and related pathways involved in adhesion formation using bioinformatics analysis methods. We performed quantitative PCR and western blotting in vivo to validate the results preliminarily.

RESULTS

In total, 446 expressed genes were altered in peritoneal adhesion. We found that several hub genes (e.g., tumor necrosis factor, interleukin 1 beta, interleukin 6, C-X-C motif chemokine ligand 1, C-X-C motif chemokine ligand 2) were marked as significant biomarkers. Functional analysis suggested that these genes were enriched in the Toll-like receptor signaling pathway. According to the Kyoto Encyclopedia of Genes and Genomes pathway and published studies, TLR4, myeloid differentiation primary response protein 88 (MyD88), and nuclear factor kappa B (NF-κB) played essential roles in Toll-like signaling transduction. Here, we obtained a regulatory evidence chain of TLR4/MyD88/NF-κB/inflammatory cytokines/peritoneal adhesion involved in the pathogenesis of postoperative adhesion. The results of the microarray analysis were verified by the animal experiments. These findings may extend our understanding of the molecular mechanisms of PPA.

CONCLUSION

The regulatory evidence chain of TLR4/MyD88/NF-κB/inflammatory cytokines/peritoneal adhesion may play key roles in the pathogenesis of PPA. Future studies are required to validate our findings.

Adhesion-related readmissions after open and laparoscopic surgery: a retrospective cohort study (SCAR update)

BACKGROUND

Adhesions are the most common driver of long-term morbidity after abdominal surgery. Although laparoscopy can reduce adhesion formation, the effect of minimally invasive surgery on long-term adhesion-related morbidity remains unknown. We aimed to assess the impact of laparoscopy on adhesion-related readmissions in a population-based cohort.

METHODS

We did a retrospective cohort study of patients of any age who had abdominal or pelvic surgery done using laparoscopic or open approaches between June 1, 2009, and June 30, 2011, using validated population data from the Scottish National Health Service. All patients who had surgery were followed up until Dec 31, 2017. The primary outcome measure was the incidence of hospital readmissions directly related to adhesions in the laparoscopic and open surgery cohorts at 5 years. Readmissions were categorised as directly related to adhesions, possibly related to adhesions, and readmissions for an operation that was potentially complicated by adhesions. We did subgroup analyses of readmissions by anatomical site of surgery and used Kaplan-Meier analyses to assess differences in survival across subgroups. We used multivariable Cox-regression analysis to determine whether surgical approach was an independent and significant risk factor for adhesion-related readmissions.

FINDINGS

Between June 1, 2009, and June 30, 2011, 72 270 patients had an index abdominal or pelvic surgery, of whom 21 519 (29·8%) had laparoscopic index surgery and 50 751 (70·2%) had open surgery. Of the 72 270 patients who had surgery, 2527 patients (3·5%) were readmitted within 5 years of surgery for disorders directly related to adhesions, 12 687 (17·6%) for disorders possibly related to adhesions, and 9436 (13·1%) for operations potentially complicated by adhesions. Of the 21 519 patients who had laparoscopic surgery, 359 (1·7% [95% CI 1·5-1·9]) were readmitted for disorders directly related to adhesions compared with 2168 (4·3% [4·1-4·5]) of 50 751 patients in the open surgery cohort (p<0·0001). 3443 (16·0% [15·6-16·4]) of 21 519 patients in the laparoscopic surgery cohort were readmitted for disorders possibly related to adhesions compared with 9244 (18·2% [17·8-18·6]) of 50 751 patients in the open surgery cohort (p<0·005). In multivariate analyses, laparoscopy reduced the risk of directly related readmissions by 32% (hazard ratio [HR] 0·68, 95% CI 0·60-0·77), and of possibly related readmissions by 11% (HR 0·89, 0·85-0·94) compared with open surgery. Procedure type, malignancy, sex, and age were also independently associated with risk of adhesion-related readmissions.

INTERPRETATION

Laparoscopic surgery reduces the incidence of adhesion-related readmissions. However, the overall burden of readmissions associated with adhesions remains high. With further increases in the use of laparoscopic surgery expected in the future, the effect at the population level might become larger. Further steps remain necessary to reduce the incidence of adhesion-related postsurgical complications.

FUNDING

Dutch Adhesion Group and Nordic Pharma.

Adhesive small bowel obstruction - an update

Small bowel obstruction (SBO) accounts for 12-16% of emergency surgical admissions and 20% of emergency surgical procedures. Even with the advent of laparoscopic surgery, intra-abdominal adhesions remain a significant cause of SBO, accounting for 65% of cases. History and physical examination are essential to identify signs of bowel ischemia as this indicates a need for urgent surgical exploration. Another critical aspect of evaluation includes establishing the underlying cause for obstruction and distinguishing between adhesive and non-adhesive etiologies as adhesive SBO (ASBO) can be managed non-operatively in 70-90% of patients. A patient with a history of abdominopelvic surgery along with one or more cardinal features of obstruction should be suspected to have ASBO until proven otherwise. Triad of severe pain, pain out of proportion to the clinical findings, and presence of an abdominal scar suggest possible closed-loop obstruction. Computed tomography has higher sensitivity and specificity compared to plain films and is recommended by the Bologna guidelines. Correcting fluid and electrolyte imbalance is an initial crucial step to mitigate severe hypovolemia. Patients should proceed with surgery if symptoms of bowel compromise are present, or if symptoms do not resolve or have worsened. Surgery is indicated in patients with ischemia, strangulation, perforation, peritonitis, or failure of non-operative treatment. With advances in minimal access technology and increasing experience, laparoscopic adhesiolysis is recommended. Mechanical adhesion barriers are an effective measure to prevent adhesion formation.

A Simple Technique for the Placement of Seprafilm, a Sodium Hyaluronate or Carboxymethylcellulose Absorbable Barrier, during Laparoscopic Myomectomy

This report describes a simple technique using conventional instrumentation for the placement of Seprafilm, a sodium hyaluronate or carboxymethylcellulose absorbable barrier for adhesion prevention. A total of 378 women with uterine myomas undergoing laparoscopic myomectomies had 737 Seprafilm pieces placed. Seprafilm sheet was softened through exposure to room air for 5 minutes, cut into 4 pieces (length, 5-10 mm), rolled up alongside a plastic sheet cut from a camera drape cover, and gently placed at the right paracolic gutter. The Seprafilm pieces unfolded semiautomatically on release and were then placed on the uterus. The median time to apply per Seprafilm piece was 1 (range: 0.8-3.5) minute. We failed to place 16 pieces (16 of 737, 2.2%) in 11 patients. Virginal status, myoma weight, and the number of removed myomas were the risk factors of failed placement. Our technique for Seprafilm placement during laparoscopic myomectomy is simple and safe.

Cellulose absorbable barrier for prevention of de-novo adhesion formation at the time of laparoscopic myomectomy: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Myomectomy is the standard surgical treatment for symptomatic uterine leiomyomas, especially for patients wishing to preserve their fertility. However, this procedure is associated with adhesion formation. Several strategies have been proposed to reduce them. Cellulose absorbable barrier is widely used. We aimed to assess its effectiveness in the prevention of de-novo adhesion formation after laparoscopic myomectomy.

STUDY DESIGN

A systematic review and meta-analysis was performed by searching electronic databases (i.e. MEDLINE, Scopus, ClinicalTrials.gov, EMBASE, Sciencedirect, the Cochrane Library at the CENTRAL Register of Controlled Trials, Scielo) from their inception until May 2019. We included all randomized clinical trials (RCT) comparing use of cellulose absorbable barrier (i.e. intervention group) with either placebo or no treatment (i.e. control group) in the prevention of de-novo adhesion formation at the time of laparoscopic myomectomy. Primary and secondary outcomes were defined before data extraction. The primary outcome was the incidence of adhesions at second-look laparoscopy. The secondary outcome was the operative time.

RESULTS

Three RCT, including 366 participants, were included. All trials evaluated women undergoing laparoscopic myomectomy who were randomized to intervention (either oxidized regenerated cellulose or carboxymethylcellulose powder adhesion barrier) or no treatment (control group). Women who received treatment had significantly lower incidence of adhesions at the second look laparoscopy (RR 0.63, 95 % CI 0.40-0.99). Interventions with use of cellulose absorbable barrier were 4 min longer (MD 4 min, 95 % CI 2.82-5.18).

CONCLUSION

Use of cellulose absorbable barrier at the time of laparoscopic myomectomy reduces the risk of postoperative adhesions.

Adhesion reformation and the limited translational value of experiments with adhesion barriers: A systematic review and meta-analysis of animal models

Today, 40-66% of elective procedures in general surgery are reoperations. During reoperations, the need for adhesiolysis results in increased operative time and a more complicated convalescence. In pre-clinical evaluation, adhesion barriers are tested for their efficacy in preventing 'de novo' adhesion formation, However, it is unknown to which extent barriers are tested for prevention of adhesion reformation. The aim of this systematic review and meta-analysis is to assess the efficacy of commercially available adhesion barriers and laparoscopic adhesiolysis in preventing adhesion reformation in animal models. Pubmed and EMBASE were searched for studies which assessed peritoneal adhesion reformation after a standardized peritoneal injury (in the absence of an intra-peritoneal mesh), and reported the incidence of adhesions, or an adhesion score as outcome. Ninety-three studies were included. No study met the criteria for low risk of bias. None of the commercially available adhesion barriers significantly reduced the incidence of adhesion reformation. Three commercially available adhesion barriers reduced the adhesion score of reformed adhesions, namely Seprafilm (SMD 1.38[95% CI]; p < 0.01), PEG (SMD 2.08[95% CI]; p < 0.01) and Icodextrin (SMD 1.85[95% CI]; p < 0.01). There was no difference between laparoscopic or open adhesiolysis with regard to the incidence of adhesion reformation (RR 1.14[95% CI]; p ≥ 0.05) or the adhesion score (SMD 0.92[95% CI]; p ≥ 0.05). Neither currently commercially available adhesion barriers, nor laparoscopic adhesiolysis without using an adhesion barrier, reduces the incidence of adhesion reformation in animal models. The methodological quality of animal studies is poor.

HuoXueTongFu Formula Alleviates Intraperitoneal Adhesion by Regulating Macrophage Polarization and the SOCS/JAK2/STAT/PPAR-γ Signalling Pathway

Intraperitoneal adhesion is a common complication after abdominal surgery, which seriously affects the quality of life of patients. HuoXueTongFu Formula (HXTF) plays an important role in the prevention and treatment of intraperitoneal adhesions. However, the molecular-related mechanisms are still not fully known. In this study, the model of Intrapetitoneal adhesion was established by cecum abrasion and treated with HXTF for one week. RAW264.7 cells were given LPS, IFN-γ, IL-4, HXTF-medicated serum, and PPAR-γ agonist/antagonist, respectively. Histopathology, flow cytometry, ELISA, real-time PCR, and Western blotting were used to further detect the related protein, M1/M2 polarization tendency, and PPAR-γ nuclear translocation. The deposition of collagen fibres reduced in the local area of rats after the operation with HXTF treatment. Similar to IL-4, HXTF induced a tendency for macrophages to polarize toward M2 and promoted peroxisome proliferator-activated receptor-gamma (PPAR-γ) nuclear translocation. Furthermore, the use of HXTF and PPAR-γ agonists downregulated macrophage M1 polarization-related factors IL-1, IL-6, and TNF-alpha and upregulated M2 polarization-related factors IL-4, IL-10, and TGF-beta 1. Meanwhile, the use of HXTF and PPAR-γ agonists downregulated the SOCS3/JAK2/STAT1 pathway and activated the SOCS1/STAT6/PPAR-γ pathway. These results show that HXTF may reduce intraperitoneal adhesion by inducing macrophage M2 polarization and regulating the SOCS/JAK2/STAT/PPAR-γ pathway.

Biologically Targeted Photo-Crosslinkable Nanopatch to Prevent Postsurgical Peritoneal Adhesion

Peritoneal adhesion occurs in a majority of patients following abdominal surgery and can result in significant side effects and complications. Current strategies to minimize adhesions involve the use of nontargeted anatomical barriers that are either inefficient in protecting injured areas or lacking the adequate residence time to prevent adhesions. Herein, the development of a biologically targeted photo-crosslinkable nanopatch (pCNP) is reported that can prevent postsurgical adhesion. It is demonstrated that pCNP can form a compact protective barrier over surfaces with exposed collagen IV. Using a rat parietal peritoneal excision adhesion model, it is showed that pCNP is highly effective and safe in preventing postsurgical adhesions. This work presents a novel approach to preventing peritoneal adhesion with nanomaterials.

Cost-effectiveness of the prevention of adhesions and adhesive small bowel obstruction after colorectal surgery with adhesion barriers: a modelling study

Background

Adhesion barriers have proven to reduce adhesion-related complications in colorectal surgery. However, barriers are seldom applied. The aim of this study was to determine the cost-effectiveness of adhesion barriers in colorectal surgery.

Methods

A decision-tree model was developed to compare cost-effectiveness of no adhesion barrier with the use of an adhesion barrier in open and laparoscopic surgery. Outcomes were incidence of clinical consequences of adhesions, direct healthcare costs, and incremental cost-effectiveness ratio per adhesion prevented. Deterministic and probabilistic sensitivity analyses were performed.

Results

Adhesion barriers reduce adhesion incidence and incidence of adhesive small bowel obstruction in open and laparoscopic surgery. Adhesion barriers in open surgery reduce costs compared to no adhesion barrier ($4376 versus $4482). Using an adhesion barrier in laparoscopic procedures increases costs by $162 ($4482 versus $4320). The ICER in the laparoscopic cohort was $123. Probabilistic sensitivity analysis showed 66% and 41% probabilities of an adhesion barrier reducing costs for open and laparoscopic colorectal surgery, respectively.

Conclusion

The use of adhesion barriers in open colorectal surgery is cost-effective in preventing adhesion-related problems. In laparoscopic colorectal surgery, an adhesion barrier is effective at low costs.

Ligustrazine nanoparticles nano spray's activation on Nrf2/ARE pathway in oxidative stress injury in rats with postoperative abdominal adhesion

Background

Postoperative abdominal adhesions formation is considered a significant clinical entity implicating the healing process following major pelvic and abdominal surgery, with serious clinical complications and need for substantial health care expenditures. However, setting a physical barrier between the damage site and the neighboring tissues is a convenient and highly valid way to minimize or prevent peritoneal adhesions. The present experimental study evaluated the preventive effect of ligustrazine nanoparticles nano spray (LNNS) on postoperative abdominal adhesion in rats and explored its mechanism.

Methods

Sixty male Sprague Dawley (SD) rats were randomly divided into sham operation group, control group, sodium hyaluronate group and low, medium, and high dose LNNS groups. All groups were prepared with abdominal adhesion models except for the sham operation group. The models were made by opening the abdominal cavity to and filing the serosa in ileocecal junction. The abdominal cavity of rats in the sham operation group were only opened and sutured. The wound surface of rats in the sodium hyaluronate group, low, medium, and high dose LNNS groups were sprayed with sodium hyaluronate gel (0.5 mL/kg) and LNNS (2.5, 5, and 10 mL/kg). Rats in each group were sacrificed 7 days later. Degree of adhesion was evaluated by naked eyes and the pathological sections were scored afterwards. The collagen synthesis in adhesion tissues was detected by Masson's trichrome stain, and the activities of reactive oxygen species (ROS), nitric oxide (NO), superoxide dismutase (SOD) and malondialdehyde (MDA) in peritoneal fluid were detected with the method of chromogenic substrate. Levels of TNF-α and IL-1β in serum, and the protein levels of MCP-1 and MMP-9 in adhesion tissues were detected by ELISA and. immunohistochemistry respectively. RT-PCR and Western blot were utilized to identify the expression levels of Nrf2, heme-oxygenase-1, NQO1 mRNA and protein in adherent intestinal tissues.

Results

Compared with the control group, the incidence of postoperative abdominal adhesions decreased in the low, medium and high dose LNNS groups, while the expression of SOD in the peritoneal fluid significantly increased. The expression levels of ROS, MDA and NO were reduced remarkably (P<0.05), so were the expression levels of serum TNF-α and IL-1β (P<0.01) and the expression of MCP-1 protein in adhesion tissues. The MMP-9 protein expression, and Nrf2, heme-oxygenase-1, NQO1 mRNA and protein expressions increased.

Conclusions

LNNS with medium or high dose can significantly reduce the incidence of postoperative abdominal adhesions, the mechanism of which may be the activation of Nrf2/ARE pathway, resulting in the up-regulation of Nrf2, heme-oxygenase-1, NQO1 and mRNA expression, as well as the levels of TNF-α and IL-1β in peripheral blood and the expression of MCP-1 protein in adhesion tissues. Meanwhile, the content of MMP-9 protein in adhesion tissues were raised, and oxidative stress and inflammatory response are released.