Postoperative intraperitoneal adhesion pathophysiology

Development and validation of machine learning models and nomograms for predicting the surgical difficulty of laparoscopic resection in rectal cancer

BACKGROUND

The objective of this study is to develop and validate a machine learning (ML) prediction model for the assessment of laparoscopic total mesorectal excision (LaTME) surgery difficulty, as well as to identify independent risk factors that influence surgical difficulty. Establishing a nomogram aims to assist clinical practitioners in formulating more effective surgical plans before the procedure.

METHODS

This study included 186 patients with rectal cancer who underwent LaTME from January 2018 to December 2020. They were divided into a training cohort (n = 131) versus a validation cohort (n = 55). The difficulty of LaTME was defined based on Escal's et al. scoring criteria with modifications. We utilized Lasso regression to screen the preoperative clinical characteristic variables and intraoperative information most relevant to surgical difficulty for the development and validation of four ML models: logistic regression (LR), support vector machine (SVM), random forest (RF), and decision tree (DT). The performance of the model was assessed based on the area under the receiver operating characteristic curve(AUC), sensitivity, specificity, and accuracy. Logistic regression-based column-line plots were created to visualize the predictive model. Consistency statistics (C-statistic) and calibration curves were used to discriminate and calibrate the nomogram, respectively.

RESULTS

In the validation cohort, all four ML models demonstrate good performance: SVM AUC = 0.987, RF AUC = 0.953, LR AUC = 0.950, and DT AUC = 0.904. To enhance visual evaluation, a logistic regression-based nomogram has been established. Predictive factors included in the nomogram are body mass index (BMI), distance between the tumor to the dentate line ≤ 10 cm, radiodensity of visceral adipose tissue (VAT), area of subcutaneous adipose tissue (SAT), tumor diameter >3 cm, and comorbid hypertension.

CONCLUSION

In this study, four ML models based on intraoperative and preoperative risk factors and a nomogram based on logistic regression may be of help to surgeons in evaluating the surgical difficulty before operation and adopting appropriate responses and surgical protocols.

Inhibition of chemokine receptor CXCR2 attenuates postoperative peritoneal adhesion formation

BACKGROUND

Postoperative peritoneal adhesions remain a problem after general and gynecological surgery.

METHODS

Hematoxylin and eosin and Masson's trichrome staining of ischemic buttons were performed 6, 12, 24 hours, and 7 days after button induction. Scanning electron microscopy, ribonucleic acid sequencing, quantitative real-time polymerase chain reaction, immunohistochemical staining, and flow cytometry were used to elucidate the pathophysiology of postoperative peritoneal adhesions.

RESULTS

The results showed that thickening of the peritoneum and abscission of mesothelial cells and collagen fibers increased significantly on the surface of the "button" in the control groups at 24 hours postoperatively. Scanning electron microscopy revealed a large number of granulocytes on the button surface in the control group at 24 hours. Ribonucleic acid sequencing and quantitative real-time polymerase chain reaction also revealed that CXCR2 expression was significantly upregulated. In addition, danirixin, a CXCR2 inhibitor, reduced abdominal adhesion in the injured area by inhibiting the infiltration of inflammatory cells and collagen production. Immunohistochemical staining showed decreased expression of CXCR2 in the adhesion area 7 days after surgery in the treatment group. Flow cytometry showed a significantly decreased neutrophil ratio in the treatment group compared with that in the control group 24 hours after the operation.

CONCLUSIONS

Inflammation plays an important role in the early stages of postoperative peritoneal adhesion formation, whereas collagen fibers and angiogenesis play important roles in the late stages. The CXCL2-CXCL3-CXCR2 signaling axis is an important link in the mechanism of postoperative peritoneal adhesion formation, and the application of CXCR2 inhibitors can alleviate the formation of postoperative peritoneal adhesions.

Minimally Invasive Extended Totally Extraperitoneal Versus Transabdominal Retromuscular Ventral Hernia Mesh Repair: Systematic Review and Meta-Analysis

Introduction: Minimally invasive surgery for ventral hernia repair (MIS-VHR) with mesh in retromuscular plane can be performed by either transabdominally (TA-RM) or via enhanced view totally extraperitoneal approach (eTEP). Although both techniques offer the mesh extension in the best anatomical space, closure of hernia defect, avoidance of traumatic fixation, the superiority of one approach over another is not established. This systematic review and meta-analysis were set up to analyze safety and efficacy of eTEP in comparison with TA-RM. Materials and Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) framework was used as guideline to conduct systematic search of literature. Studies that provided comparative data of MIS-VHR using eTEP versus TA-RM were identified. Primary outcomes were major complications. These were defined as grade III-IV according to Clavien-Dindo classification. Secondary outcomes included: surgical site infection (SSI) rates, seroma rates, surgical site occurrence requiring procedural intervention (SSOPI), minor complications (Clavien-Dindo grade I-II), intraoperative complications, recurrence rate, postoperative ileus, duration of surgery, postoperative pain. Random- and fixed-effects models of statistical analysis were used. Risk difference (RD) was computated for binary outcomes (major and minor complications, SSI, seroma, SSOPI, recurrence, ileus) with 95% confidence intervals. I2 test was used to assess statistical heterogeneity. Risk of bias assessment was performed using Newcastle-Ottawa framework. Results: There were 3 observational studies that enrolled 370 participants. In the eTEP group there were 166 patients and, in the TA-RM group there were 204 patients. There was no significant RD with regard to major complications (RD -0.02 [-0.06 to 0.02], test for overall effect: Z = 0.86 [P = .39]). There was no significant RD in occurrence of minor complications, SSI, seroma, SSOPI, recurrence, ileus. Conclusions: Both eTEP and TA-RM were found to have equal safety profile. Further high-quality studies evaluating patient reported outcomes and late recurrence may be useful. PROSPERO registration number: CRD42023429160.

Development of a novel model for intraarticular adhesion in rat knee joint

In this study, a novel rat model of knee joint adhesion was developed, and its formation was analyzed quantitatively over time. Thirty-nine Wistar rats were randomly divided into intact control (n = 3) and experimental (n = 36) groups. The latter was equally divided into three groups according to the experimental intervention: fixed with deep bending of the knee joint (group I), fixed after incision of the capsule (group II), and fixed after exposure of the patellofemoral joint to artificial patellar subluxation (group III). All rats were subdivided according to their joint immobilization period (1, 2, or 4 weeks). Thereafter, the limited range of motion of the knee joint with (limited knee range of motion) and without (limited knee joint intrinsic range of motion) skin and muscles were measured. The lengths of adhesions of the anterior knee joint and posterior capsules were evaluated histologically. The limited intrinsic range of motion of the knee joint was found to be increased in groups II and III compared to that in group I 4 weeks after immobilization. Adhesions were confirmed within 1 week after immobilization in groups II and III. The length of the adhesions in group III was significantly longer than in other groups at 2 weeks and remained longer than in group I at 4 weeks. This model may contribute to the assessment of the adhesion process and development of new therapeutic avenues following trauma or surgical invasion.

Peritoneal lavage with Glycyrrhiza glabra is effective in preventing peritoneal adhesion in a rat model

BACKGROUND

Intraperitoneal adhesion formation is a significant problem following surgeries, resulting in substantial clinical and economic consequences. Glycyrrhiza glabra has several pharmacological properties consisting of anti-inflammatory, anti-microbial, anti-oxidant, anti-cancer, and immunomodulatory activities.

AIM

Therefore, we aimed to investigate the impacts of G. glabra on the development of post-operative abdominal adhesion in a rat model.

METHODS

Male Wistar rats weighing 200-250 g were divided into six groups (n = 8): Group 1: normal group (non-surgical), and the surgical groups including Group 2: control group received the vehicle, Group 3: G. glabra 0.5% w/v, Group 4: G. glabra 1% w/v, Group 5: G. glabra 2% w/v, and Group 6: dexamethasone, 0.4% w/v. The intra-abdominal adhesion was performed utilizing soft sterilized sandpaper on one side of the cecum, and the peritoneum was slightly washed with 2 ml of the extract or vehicle. In addition, macroscopic examination of adhesion scoring and the levels of inflammatory mediators [interferon (IFN)-γ, prostaglandin E₂ (PGE₂)], fibrosis markers [interleukin (IL)-4, transforming growth factor (TGF)-ꞵ], and oxidative factors [malondialdehyde (MDA), nitric oxide metabolites (NO), and reduced glutathione (GSH)] were evaluated. In vitro toxicities were also done on mouse fibroblast L929 and NIH/3T3 cell lines.

RESULTS

We found higher levels of adhesion (P < 0.001), IFN-γ(P < 0.001), PGE₂(P < 0.001), IL-4(P < 0.001), TGF-β(P < 0.001), MDA(P < 0.001), and NO(P < 0.001), and lower levels of GSH(P < 0.001) in the control group. In contrast, G. glabra concentration dependent and dexamethasone alleviated the levels of adhesion (P < 0.05), inflammatory mediators (P < 0.001-0.05), fibrosis (P < 0.001-0.05), and oxidative (P < 0.001-0.05) factors, while propagating the anti-oxidant marker (P < 0.001-0.05) in comparison to the control group. Results also showed that the extract did not significantly reduce cell viability up to 300 µg/ml (P > 0.05).

CONCLUSION

G. glabra could concentration-dependently mitigate peritoneal adhesion formation through its anti-inflammatory, anti-fibrosis, and anti-oxidant properties. However, further clinical investigations are required to approve that G. glabra may be a promising candidate against post-surgical adhesive complications.

Effect of Suture Used for Closure of Mesenteric Defects After Laparoscopic Roux-en-Y Gastric Bypass: Single-Center Study

INTRODUCTION

Small bowel obstruction (SBO) due to internal herniation (IH) is a well-known complication of laparoscopic Roux-en-Y gastric bypass (LRYGBP). The objective of this study is to evaluate different types of non-absorbable sutures used for closure of the defects regarding the incidence of SBO due to IH/adhesions, adhesion formation in general, or reopening of the defects.

METHODS

A single-center retrospective study was performed. Patients who underwent LRYGBP were divided in 3 groups: group A closure of the defects with monofilament Polypropylene suture (Prolene®), group B with braided polyester suture (Ethibond®), group C with barbed knotless Polybutester suture (V-Loc®). Descriptive statistics were performed regarding SBO due to IH/adhesions, adhesion formation, and reopening of closed defects.

RESULTS

From 5145 patients, 224 patients underwent exploratory laparoscopy for suspicion of SBO. Mean time interval was 28.4 months. IH or intermittent IH was found in 1.94% in group A, 1.78% in group B, and 1.40% in group C. Obstruction due to adhesions was found in 0.70%, 0.36%, and 0.42% per group, respectively. Adhesions in general were observed in 1.47% in group A, 1.43% in group B, and 1.06% in group C. The incidence of reopening was higher in group A (2.24%) in comparison with group B (1.13%, P = 0.041) and group C (1.05%, P = 0.001).

CONCLUSIONS

After descriptive analysis, these results can withhold no difference among the 3 non-absorbable sutures regarding incidence of SBO due to IH or SBO due to adhesions, yet tendency for higher reopening rates after closure with monofilament Polypropylene suture is observed.

A review of animal models for post-operative pericardial adhesions

Post-operative pericardial adhesions remain a serious complication after cardiac surgery that can lead to increased morbidity and mortality. Fibrous adhesions can destroy tissue planes leading to injury of surrounding vasculature, lengthening of operation time, and increased healthcare costs. While animal models are necessary for studying the formation and prevention of post-operative pericardial adhesions, a standardized animal model for inducing post-operative pericardial adhesions has not yet been established. In order to address this barrier to progress, an analysis of the literature on animal models for post-operative pericardial adhesions was performed. The animal model, method used to induce adhesions, and the time to allow development of adhesions were analyzed. Our analysis found that introduction of autologous blood into the pericardial cavity in addition to physical abrasion of the epicardium caused more severe adhesion formation in comparison to abrasion alone or abrasion with desiccation (vs. abrasion alone p = 0.0002; vs. abrasion and desiccation p = 0.0184). The most common time frame allowed for adhesion formation was 2 weeks, with the shortest time being 10 days and the longest being 12 months. Finally, we found that the difference in adhesion severity in all animal species was similar, suggesting the major determinants for the choice of model are animal size, animal cost, and the availability of research tools in the particular model. This survey of the literature provides a rational guide for researchers to select the appropriate adhesion induction modality, animal model, and time allowed for the development of adhesions.

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.

A nomogram predicting the difficulty of laparoscopic surgery for rectal cancer

PURPOSE

This study aimed to identify the risk factors associated with performing a difficult laparoscopic radical resection of rectal cancer, and to establish a predictive nomogram to help individual clinical treatment decisions.

METHODS

A total of 977 patients with rectal cancer who underwent laparoscopic radical resection between January 2014 and December 2016 were enrolled in this study. The difficulty of laparoscopic-assisted rectal resection (LARR) was defined according to the scoring criteria reported by Escal. A logistic regression analysis was performed to identify the variables that may affect the difficulty of LARR, and a nomogram predicting the surgical difficulty was created.

RESULTS

A multivariate analysis demonstrated that a BMI > 28 kg/m², the distance between the tumor and the anal margin ≤ 5 cm, the maximum transverse tumor diameter > 3 cm tumor, interspinous distance < 10 cm, history of abdominal surgery, and preoperative radiotherapy were independent risk factors and they were, therefore, included in the predictive nomogram for identifying a difficult LARR.

CONCLUSIONS

This study defined a difficult LARR and identified independent risk factors for a difficult operation and created a predictive nomogram for difficult LARR. This nomogram may facilitate the stratification of patients at risk for being associated with a difficult LARR for rectal cancer.

Diagnosis and management of small bowel obstruction in virgin abdomen: a WSES position paper

Background

Small bowel obstruction (SBO) is a common surgical emergency, causing high morbidity and healthcare costs. The majority of SBOs are caused by adhesions that result from previous surgeries. Bowel obstruction, however, also occurs in patients without previous operation or known pathology, a so called virgin abdomen. It is unknown if small bowel obstruction in the virgin abdomen (SBO-VA) can be managed according to the same principles as other cases of small bowel obstruction. The aim of this position paper is to evaluate the available evidence on etiology and management of small bowel obstruction in the virgin abdomen.

Methods

This is a narrative review with scoping aspects. Clinical topics covered in this review include epidemiology and etiology of SBO-VA, diagnosis and imaging, initial assessment, the role of surgical management in SBO-VA, and the role of non-operative management in SBO-VA.

Results

Our scoping search revealed seven original studies reporting original patient data related to SBO-VA. All the included studies are retrospective cohorts, with populations ranging between 44 and 103 patients with SBO-VA. Adhesions were found to be the cause of the obstruction in approximately half of the reported cases of SBO-VA. A relatively high number of cases of SBO-VA were managed surgically with studies reporting 39–83%. However, in cases where a trial of non-operative management was started, this was generally successful.

Conclusion

The data available suggest that etiology and treatment results for patients with SBO-VA are largely comparable to the results in patients with SBO after previous abdominal surgery. We therefore propose that patients with a virgin abdomen could be treated according to existing guidelines for SBO and adhesive small bowel obstruction.

Antifibrotic Effect of Bletilla striata Polysaccharide-Resveratrol-Impregnated Dual-Layer Carboxymethyl Cellulose-Based Sponge for The Prevention of Epidural Fibrosis after Laminectomy

The application of antifibrotic materials can alleviate epidural fibrosis by restricting excessive fibroblast proliferation and mitigating scar tissue formation. Here, a biodegradable carboxymethyl cellulose (CMC)-Bletilla striata polysaccharide (BSP)-resveratrol (RES) sponge was fabricated to inhibit scar tissue formation post laminectomy surgery. Fibroblasts NIH/3T3, myoblasts C2C12, neural cells PC-12, and Schwann cells RSC96 were used to evaluate the in vitro cytocompatibility. Laminectomies on 10 Sprague–Dawley rats with/without the application of the CMC-BSP-RES sponge were performed. The severity of adhesion between the dura mater and formed scar tissue was qualitatively scored. All cell lines exhibited good viability with no significant difference in cytotoxicity when cultured with variable extractions of the CMC-BSP-RES sponge. S100a4 and P4hb expressions were downregulated in NIH/3T3 cultured in the CMC-BSP-RES sponge, implying that this sponge potentially inhibits fibroblast activity. No post-operative shrinkage or dura mater expansion along the surgical site was detected. The peel-off tests revealed that the tenacity of adhesion de-creased. Histopathological examinations verified that the average number of fibroblasts in the CMC-BSP-RES group considerably decreased. The CMC-BSP-RES sponge is a biocompatible and effective material for alleviating post-operative epidural fibrosis and mitigating fibroblast expression following laminectomy.

Complete pathologic response after two-stage cytoreductive surgery with HIPEC for bulky pseudomyxoma peritonei: proof of concept

Introduction: Pseudomyxoma peritonei (PMP) is a rare disease characterized by the progressive accumulation of mucinous ascites and peritoneal implants. The optimal treatment for PMP includes the association of complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). For patients with a large burdensome disease, the completeness of cytoreduction sometimes requires maximal effort surgery. The aim of this article is to provide proof of concept for two stage cytoreductive surgery (CRS) in this category of patients.Methods and materials: A two stage CRS and HIPEC with oxaliplatin was proposed for patients with bulky PMP including important involvement of the serosal surfaces of the bowel or colon who had an impaired nutritional status. The residual disease at the end of the first stage was less than 5 mm of thickness on several implants. Clinical, surgical and histopathological variables were analyzed.Results: All eight patients completed the two-stage strategy. Mortality was nil. One Clavien Dindo grade 3 event occurred in each stage. After a median follow up of 29.5 months, all patients were alive and free of recurrence. All of the patients had histopathological complete response on the specimens obtained from the residual sites during the second stage surgery.Conclusions: Two-stage surgical strategy is feasible for bulky PMP patients and it is associated with little high-grade morbidity and enhanced visceral sparing.

A nano chitosan membrane barrier prepared via Nanospider technology with non-toxic solvent for peritoneal adhesions' prevention

Peritoneal adhesion is one of the most common postsurgical complications and can cause bowel obstruction, pelvic pain, and infertility. Setting up a physical barrier directly between the injured site and surrounding tissues is an effective solution for preventing this adverse situation. This study investigated a chitosan electrospun membrane (CSEM) as a potent anti-adhesion barrier, which was prepared by a needleless technology called Nanospider. Scanning electron microscopy revealed that CSEM is a laminated nanofiber with good mechanical properties. The fiber is uniform with the diameter distributing in the range of 100-120 nm. The tensile strength can reach 27.45 ± 6.30 MPa with a maximum elongation at break of 18.50 ± 1.44%, which makes it stick easily to damaged parts but not to be easily damaged by tissue friction. The growth of S. aureus on CSEM was 59.18% lower than the control at 10 h, which indicates its better antibacterial property. In addition, CSEM has good coagulant and biocompatibility characteristics. It can perform hemostatic function within 10 min and the L929 mouse fibroblast viability on it was 92.18% ± 1.08% on the seventh day. In vivo experiments indicated that CSEM significantly prevented peritoneal adhesions within four weeks after surgery with wound surface coverage. These results indicate that CSEM is a promising anti-adhesion barrier material.

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.

Postoperative peritoneal adhesion: an update on physiopathology and novel traditional herbal and modern medical therapeutics

Postoperative peritoneal adhesion (PPA) is a serious clinical condition that affects the high percentage of patients after abdominal surgery. In this review, we have tried to focus on pathophysiology and different underlying signal pathways of adhesion formation based on recent progress in the molecular and cellular mechanisms. Also, the strategies, developed based on traditional herbal and modern medicines, to prevent and treat the PPA via regulation of the molecular mechanisms were investigated. The search engines such as Google Scholar, PubMed, Scopus, and Science Direct have been used to evaluate the current literature related to the pathogenesis of adhesion formation and novel products. Recently, different mechanisms have been defined for adhesion formation, mainly categorized in fibrin formation and adhesion fibroblast function, inflammation, and angiogenesis. Therefore, the suppression of these mechanisms via traditional and modern medicine has been suggested in several studies. While different strategies with encouraging findings have been developed, most of the studies showed contradictory results and were performed on animals. The herbal products have been introduced as safe and effective agent which can be considered in future preclinical and clinical studies. Although a wide range of therapeutics based on traditional and modern medicines have been suggested, there is no agreement in the efficacy of these methods to prevent or treat adhesion formation after surgeries. Further basic and clinical researches are still needed to propose the efficiency of recommended strategies for prevention and treatment of PPA.

The effect of addition of dexamethasone into normal saline irrigation solution on Prevention of Intraperitoneal Adhesion Post Laparotomy in wistar rats (Rattus norvegicus)

Introduction

Intraperitoneal adhesion is a pathological condition of adhesion between the omentum, intestine and abdominal wall. The purpose of this study was to determine the effect of adding dexamethasone into normal saline fluid to prevent intra peritoneal adhesion.

Materials and methods

This study used experimental post-test only control group design. There were four treatment groups using six white rats in each group: group I without administration of normal saline and dexamethasone, group II with administration of normal saline irrigation, group III by adding dexamethasone dose 0.2 mg/BW into 5 cc normal saline, and group IV by adding 0.5 mg/BW into 5 cc normal saline. Laparotomy was performed to all samples followed by excoriation and abrasion in cecum and terminal ileum using gauze. Intra peritoneal adhesion assessment was carried out on the 10th day post laparotomy. Macroscopic and microscopic assessments were performed to evaluate formation of collagen, fibrin and the spread of inflammatory cells of each group.

Results

From macroscopic observations, it was found that the average adhesion that occurred was 3.333; 2.333; 0.666; 0.333 by using statistical calculations with one-way ANOVA with P value of 0.000. Post-Hoc analysis showed that the administration of dexamethasone 0.5 mg/BW is proven to minimize the occurrence of adhesion between the 3 groups. Microscopic assessment of the formation of collagen, fibrin and the spread of inflammatory cells by one-way ANOVA produced P 0.000 in all three parameters, but the dose of dexamethasone administration between 0.2 mg/BW and 0.5 kg/BW did not prove significant in either group.

Conclusion

There is evidence that the addition of dexamethasone to normal saline as an irrigation liquid during laparotomy can reduce the occurrence of adhesion. However, the dose difference was not proven to be better in this study. Further studies are suggested to use more experimental animals.

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Administration of dexamethasone was proven to reduce the amount of the three parameters.

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Addition of dexamethasone to normal saline as an irrigation liquid during laparotomy can reduce the occurrence of adhesion.

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Administration of normal saline can reduce inflammatory cells in the intraperitoneal adhesion tissue.

Does CO2 pneumoperitoneum in laparoscopy interfere with collagen deposition in abdominal surgical wounds?

Purpose To determine by histomorphometric analysis whether CO2 pneumoperitoneum interferes with collagen deposition in surgical wounds in the aponeurosis of rats. Methods This experiment involved 80 male Wistar rats, randomly allocated into four groups according to pneumoperitoneum period (PRE: 30 min preoperatively; POST: 30 min postoperatively; PP: 30 min pre- and postoperatively; C: control group). CO2 pneumoperitoneum was insufflated to 5 mmHg of pressure. A laparotomy was performed; 1 cm of the left colon was then resected, and an end-to-end anastomosis was performed to simulate surgical trauma, after which the abdominal wall was closed. On postoperative days 7 or 14, a sample of the abdominal wall was collected, stained with picrosirius red and observed under polarized light in an optical microscope. The amount of collagen was estimated by computerized histomorphometric analysis. Results There were no significant differences in collagen deposition between the control and experimental groups on postoperative days 7 (p=0.720) or 14 (p=0.933). The amount of collagen increased as expected in all groups between postoperative days 7 and 14 (p=0.0003). Conclusion At 5 mmHg, CO2 pneumoperitoneum does not interfere with collagen deposition in abdominal wall surgical wounds in rats.

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.

Hemoperitoneum as a precursor of deep pelvic endometriosis: prospective cohort study

OBJECTIVE

To determine whether significant hemoperitoneum could be a precursor of deep pelvic endometriosis in non-pregnant premenopausal women presenting with severe acute lower abdominal pain.

METHODS

This was a prospective observational cohort study carried out at a dedicated gynecological diagnostic unit over a period of 18 months. We included consecutive non-pregnant, premenopausal women who attended with severe acute lower abdominal pain and underwent a pelvic ultrasound examination. Women were triaged for surgical or conservative management depending on the cause of pain and severity of their symptoms. Those who were selected for conservative management were invited for follow-up ultrasound scans. The main outcome measure was evidence of newly developed deep endometriosis at follow-up examination.

RESULTS

Of 118 non-pregnant women who attended our unit with severe acute lower abdominal pain, 20 underwent emergency surgery and 17 had a history of endometriosis, or evidence of endometriosis on the initial scan, and were excluded from the study. Therefore, conservative management was employed in 81 women, eight of whom had evidence of significant hemoperitoneum at presentation. A total of 35 women attended for all follow-up ultrasound scans. At the completion of follow-up, four of six (67% (95% CI, 22-96%)) women who presented initially with significant intra-abdominal bleeding had developed new evidence of deep endometriosis, compared with one of 29 (3% (95% CI, 0-18%)) of those without hemoperitoneum (relative risk, 19.3 (95% CI, 3-144); P < 0.001).

CONCLUSION

In some women, the presence of significant hemoperitoneum that is managed conservatively precedes the development of deep endometriosis. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Comparative study of peritoneal adhesions after intraperitoneal implantation in rats of meshes of polypropylene versus polypropylene/polyglecaprone versus polyester/porcine collagen

PURPOSE

To Compare the extent and intensity of adhesions formed between the intra-abdominal organs and the intraperitoneal implants of polypropylene mesh versus polypropylene/polyglecaprone versus polyester/porcine collagen used for correction of abdominal wall defect in rats.

METHODS

After the defect in the abdominal wall, thirty Wistar rats were placed in three groups (ten animals each) for intraperitoneal mesh implant: polypropylene group, polypropylene/polyglecaprone group, and polyester/porcine collagen group. The macroscopic evaluation of the extent and intensity of adhesions was performed 21 days after the implant.

RESULTS

The polypropylene group had a higher statistically significant impairment due to visceral adhesions (p value = 0.002) and a higher degree of intense adherence in relation to polypropylene/polyglecaprone and polyester/porcine collagen groups (p value<0.001). The polyester/porcine collagen group showed more intense adhesions than the polypropylene/polyglecaprone group (p value=0.035).

CONCLUSIONS

The intraperitoneal implantation of polypropylene meshes to correct defects of the abdominal wall caused the appearance of extensive and firm adhesions to intra-abdominal structures. The use of polypropylene/polyglecaprone or polyester/porcine collagen tissue-separating meshes reduces the number and degree of adhesions formed.

Fibrin-Targeted Polymerized Shell Microbubbles as Potential Theranostic Agents for Surgical Adhesions

The development of new therapies for surgical adhesions has proven to be difficult as there is no consistently effective way to assess treatment efficacy in clinical trials without performing a second surgery, which can result in additional adhesions. We have developed lipid microbubble formulations that use a short peptide sequence, CREKA, to target fibrin, the molecule that forms nascent adhesions. These targeted polymerized shell microbubbles (PSMs) are designed to allow ultrasound imaging of early adhesions for diagnostic purposes and for evaluating the success of potential treatments in clinical trials while acting as a possible treatment. In this study, we show that CREKA-targeted microbubbles preferentially bind fibrin over fibrinogen and are stable for long periods of time (∼48 h), that these bound microbubbles can be visualized by ultrasound, and that neither these lipid-based bubbles nor their diagnostic-ultrasound-induced vibrations damage mesothelial cells in vitro. Moreover, these bubbles show the potential to identify adhesionlike fibrin formations and may hold promise in blocking or breaking up fibrin formations in vivo.

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

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

Extrudable salicylic acid-based poly(anhydride-esters) for injectable drug releasing applications

Injectable biomaterials have attracted more and more interest owing to their advantages over traditional open surgeries: minimal invasive procedure and ease of handling. Commonly used synthetic injectable polymers exhibited low drug loading and poor biodegradability. In this work, we describe a novel series of degradable copolymers comprising salicylic acid–based poly(anhydride-esters) and poly(ethylene glycol) subunits suitable for injectable drug releasing applications. By tuning the rheology properties, these salicylic acid–based poly(anhydride-esters) and poly(ethylene glycol) copolymers may function as injectable drug delivery vehicles that deliver salicylic acid at the injury site. These copolymers were designed to have glass transition temperatures (Tg) below 0ºC, resulting in extrudable polymers that behave like viscous fluids at room temperature. Salicylic acid–based poly(anhydride-esters) and poly(ethylene glycol) copolymers of different ratios (2:1, 1:1, and 1:2 salicylic acid–based poly(anhydride-esters) and poly(ethylene glycol)) were synthesized and characterized by nuclear magnetic resonance and Fourier-transform infrared spectroscopies. Their shear viscosities were determined both at room and physiological temperatures. The in vitro drug release profiles, cytotoxicity, and anti-inflammatory activities were assessed. The shear viscosities were found to compare favorably with current injectable barrier materials on the market.

Chinese Trauma Surgeon Association for management guidelines of vacuum sealing drainage application in abdominal surgeries-Update and systematic review

Vacuum sealing drainage (VSD) is frequently used in abdominal surgeries. However, relevant guidelines are rare. Chinese Trauma Surgeon Association organized a committee composed of 28 experts across China in July 2017, aiming to provide an evidence-based recommendation for the application of VSD in abdominal surgeries. Eleven questions regarding the use of VSD in abdominal surgeries were addressed: (1) which type of materials should be respectively chosen for the intraperitoneal cavity, retroperitoneal cavity and superficial incisions? (2) Can VSD be preventively used for a high-risk abdominal incision with primary suture? (3) Can VSD be used in severely contaminated/infected abdominal surgical sites? (4) Can VSD be used for temporary abdominal cavity closure under some special conditions such as severe abdominal trauma, infection, liver transplantation and intra-abdominal volume increment in abdominal compartment syndrome? (5) Can VSD be used in abdominal organ inflammation, injury, or postoperative drainage? (6) Can VSD be used in the treatment of intestinal fistula and pancreatic fistula? (7) Can VSD be used in the treatment of intra-abdominal and extra-peritoneal abscess? (8) Can VSD be used in the treatment of abdominal wall wounds, wound cavity, and defects? (9) Does VSD increase the risk of bleeding? (10) Does VSD increase the risk of intestinal wall injury? (11) Does VSD increase the risk of peritoneal adhesion? Focusing on these questions, evidence-based recommendations were given accordingly. VSD was strongly recommended regarding the questions 2-4. Weak recommendations were made regarding questions 1 and 5-11. Proper use of VSD in abdominal surgeries can lower the risk of infection in abdominal incisions with primary suture, treat severely contaminated/infected surgical sites and facilitate temporary abdominal cavity closure.

A new bioabsorbable polymer film to prevent peritoneal adhesions validated in a post-surgical animal model

Background

Peritoneal adhesions are a serious surgical postoperative complication. The aim of this study is to investigate, in a rat model, the anti-adhesive effects of a bioabsorbable film of polymer combining polyethylene glycol and polylactic acid.

Materials and methods

Sixty-three animals were randomized into five groups according to the anti-adhesion treatment: Hyalobarrier^®, Seprafilm^®, Polymer A (PA), Polymer B (PB), and control. The rats were euthanized on days 5 and 12 to evaluate the extent, severity and degree of adhesions and histopathological changes. Three animals were euthanized at day 2 in PA, PB and control groups to observe the in vivo elimination.

Results

Macroscopic adhesion formation was significantly lower in the PA group than in the control group at day 5 (median adhesion score 0±0 vs 9.6 ±0.5 p = 0.002) and at day 12 (0±0 vs 7.3±4 p = 0.02). Furthermore, median adhesion score at day 5 was significantly lower in the PA group than in the Seprafilm group (0±0 vs 4.2± 3.9 p = 0.03). Residence time of PA seems longer than PB.

Conclusion

The PA bioabsorbable film seems efficient in preventing the formation of peritoneal adhesions.

Implementation of phospholipids as pharmacological modalities for postoperative adhesions prevention

Adhesions formation is considered a significant clinical entity implicating the healing process following major abdominal surgery, with serious clinical consequences and need for substantial health care expenditures. Several agents and substances applied either locally or systematically could potentially function as inhibitors of the formation of peritoneal adhesions endowed by limiting tissue apposition during the critical stages of mesothelial repair. Phospholipids are identified as surfactant-like substances, acting as a temporary membrane-like coverage of serosal defects. The experimental use of phospholipids for adhesions formation totals 24 publications. All retrieved studies, out of two, demonstrated the efficacy of phospholipids use in adhesions prevention. A single intraperitoneal dose of approximately 75 mg/kg of phosphatidylcholine, for a 30-min exposure time, emerges as the standard practice in terms of efficacy in both surgical alone or combined to peritonitis settings. The findings revealing an unimpeded healing of anastomoses and laparotomy wounds support the safety of this agent. The two additional properties of intraperitoneal use of phospholipids involve the inhibition of bacterial adherence/growth following impregnation of intra-abdominal drainages with phospholipids, without influencing bacterial translocation and the elimination of peritoneal carcinosis, through inhibition of intraperitoneal adhesion of tumor cells. The latter effect is achieved by a dose of phospholipids equal to 150 mg/kg. These experimental data, support that the intraperitoneal phospholipids administration can forestall adhesions formation following intra-abdominal surgical trauma, with no considerable overdosing-related adverse effects. Furthermore, these substances could possibly attenuate posttraumatic inflammation, and inhibit intraperitoneal tumor cell adhesion.

Bologna guidelines for diagnosis and management of adhesive small bowel obstruction (ASBO): 2017 update of the evidence-based guidelines from the world society of emergency surgery ASBO working group

Background

Adhesive small bowel obstruction (ASBO) is a common surgical emergency, causing high morbidity and even some mortality. The adhesions causing such bowel obstructions are typically the footprints of previous abdominal surgical procedures. The present paper presents a revised version of the Bologna guidelines to evidence-based diagnosis and treatment of ASBO. The working group has added paragraphs on prevention of ASBO and special patient groups.

Methods

The guideline was written under the auspices of the World Society of Emergency Surgery by the ASBO working group. A systematic literature search was performed prior to the update of the guidelines to identify relevant new papers on epidemiology, diagnosis, and treatment of ASBO. Literature was critically appraised according to an evidence-based guideline development method. Final recommendations were approved by the workgroup, taking into account the level of evidence of the conclusion.

Recommendations

Adhesion formation might be reduced by minimally invasive surgical techniques and the use of adhesion barriers. Non-operative treatment is effective in most patients with ASBO. Contraindications for non-operative treatment include peritonitis, strangulation, and ischemia. When the adhesive etiology of obstruction is unsure, or when contraindications for non-operative management might be present, CT is the diagnostic technique of choice. The principles of non-operative treatment are nil per os, naso-gastric, or long-tube decompression, and intravenous supplementation with fluids and electrolytes. When operative treatment is required, a laparoscopic approach may be beneficial for selected cases of simple ASBO.Younger patients have a higher lifetime risk for recurrent ASBO and might therefore benefit from application of adhesion barriers as both primary and secondary prevention.

Discussion

This guideline presents recommendations that can be used by surgeons who treat patients with ASBO. Scientific evidence for some aspects of ASBO management is scarce, in particular aspects relating to special patient groups. Results of a randomized trial of laparoscopic versus open surgery for ASBO are awaited.

Preventive effect of polynucleotide on post-thyroidectomy scars: A randomized, double-blinded, controlled trial

BACKGROUND AND OBJECTIVE

Polynucleotide (PN) provides a structural scaffold to induce anti-inflammatory and enhanced wound healing properties, and this study aimed to assess the efficacy of PN administration in the prevention of post-operative scars after conventional open total thyroidectomy.

STUDY DESIGN MATERIALS AND METHODS

Forty-two patients with thyroid carcinoma who underwent total thyroidectomy were randomly assigned to the study (PN administration) or control (normal saline) group. All patients underwent a single session of combined ablative and non-ablative fractional laser. The Vancouver Scar Scale (VSS), global photographic assessment, and objective scar were assessed using three-dimensional (3D) camera at baseline and at 2, 4, 8, and 16 weeks after surgery.

RESULTS

Patients who underwent PN injection demonstrated better surgical scar quality outcome. Participants in the PN administration group had lower VSS scores than the control group (2.09 ± 0.47 vs. 4.01 ± 0.55, respectively) and lower scar height (0.23 ± 0.03 vs. 0.29 ± 0.03, respectively), as measured using 3D imaging. Furthermore, in the PN injected group, the degree of erythema, and pigmentation of the scar were less prominent. No patient developed hypertrophic scar or keloids on the surgical site. No other adverse events, including post-inflammatory hyperpigmentation, scarring, or infection, were observed.

CONCLUSION

Adjuvant administration of PN along with conventional fractional laser treatment led to more favorable effect in wound healing and post-operative scar prevention after thyroidectomy. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc.

Postoperative Abdominal Adhesions: Clinical Significance and Advances in Prevention and Management

Postoperative adhesions remain one of the more challenging issues in surgical practice. Although peritoneal adhesions occur after every abdominal operation, the density, time interval to develop symptoms, and clinical presentation are highly variable with no predictable patterns. Numerous studies have investigated the pathophysiology of postoperative adhesions both in vitro and in vivo. Factors such as type and location of adhesions, as well as timing and recurrence of adhesive obstruction remain unpredictable and poorly understood. Although the majority of postoperative adhesions are clinically silent, the consequences of adhesion formation can represent a lifelong problem including chronic abdominal pain, recurrent intestinal obstruction requiring multiple hospitalizations, and infertility. Moreover, adhesive disease can become a chronic medical condition with significant morbidity and no effective therapy. Despite recent advances in surgical techniques, there is no reliable strategy to manage postoperative adhesions. We herein review the pathophysiology and clinical significance of postoperative adhesions while highlighting current techniques of prevention and treatment.

Comparative study of Polypropylene versus Parietex composite®, Vicryl® and Ultrapro® meshes, regarding the formation of intraperitoneal adhesions

PURPOSE

To compare the polypropylene mesh (Marlex®) to Vicryl®, Parietex composite® and Ultrapro® meshes to assess the occurrence of adhesions in the intraperitoneal implantation.

METHODS

Sixty Wistar rats were allocated into three groups: PP+V, in which all the animals received a polypropylene and a Vicryl® mesh; PP+PC, with the implantation of polypropylene and Parietex composite® meshes and PP+UP, in which there was implantation of polypropylene and Ultrapro®. Macroscopic analysis was performed 28 days later to assess the percentage of mesh area affected by adhesion.

RESULTS

in the PP+ V group, the Vicryl® mesh showed lower adhesion formation (p=0.013). In the PP+PC, there were no differences between polypropylene and Parietex composite® (p=0.765). In the PP+UP group, Ultrapro® and polypropylene meshes were equivalent (p=0.198) .

CONCLUSION

All the four meshes led to adhesions, with the Vicryl® mesh showing the least potential for its formation.

[Pathogenic aspects of stomach ulcerogenesis in acute intestinal obstruction]

AIM

To identify the patterns and the correlation of morphological and functional changes in stomach wall with the dynamics of different types of acute intestinal obstruction.

MATERIAL AND METHODS

The study was performed on 33 adult mongrel dogs of both genders weighing 17-20 kg. All researches were conducted in accordance with the documents, such as the 'Guide for the Care and Use of laboratory animals of the National Institute of Health (National Institute of Health - NIH, Bethesda, USA)' and 'Rules of work with experimental animals'. The same methods were used to study the morphology of stomach wall in normal conditions and after intestinal obstruction simulation. We used H & E stain, Van Gieson's picrofuchsin staining combined with Mallory. The choice of histochemical methods was determined by the need to study metabolic processes in epithelial cells and gastric mucosa glands. Einarson method for detecting total nucleic acids was used. The last group of methods was statistical analysis.

RESULTS

We determined the regularities of structural organization of microcirculation in various parts of the stomach, the correlation of morphological and functional changes in stomach wall with the dynamics of different types of acute intestinal obstruction.

CONCLUSION

Our data indicate proximal-distal gradient of gastric perfusion: the most pronounced vascular network and maximum blood flow are observed in proximal stomach in both normal conditions and acute intestinal obstruction. More tenuous and reduced blood flow was revealed in the antrum, that is morphological basis of the most frequent localization of acute ulcers in this department.

The effect of oral simvastatin on fibrinolytic activity after colorectal surgery-a pilot study

BACKGROUND

Studies conducted in animal models have shown that statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) reduce adhesion formation by upregulating fibrinolysis. The aim of this study was to determine the effect of orally administered statins on the promoters and inhibitors of the fibrinolytic pathway.

METHODS

In a previously described double-blinded clinical trial, 144 patients undergoing elective colorectal resection, or reversal of Hartmann's procedure were randomized to receive 40 mg once daily oral simvastatin 3-7 d before surgery or placebo. For the purposes of the present study, peritoneal drain fluid was collected postoperatively from patients to measure active tissue plasminogen activator (tPA), tissue plasminogen activator total antigen, active plasminogen activator inhibitor-1 (PAI-1), plasminogen activator inhibitor total antigen (PAI-1TA), plasminogen activator inhibitor-1 and tissue plasminogen activator complex (PAI-1/tPA). These were analyzed using ELISA. The number of hospitalizations and complications related to small bowel obstruction (SBO) were recorded at 2 y after surgery.

RESULTS

A total of 95 patients (72%) had sufficient peritoneal drain fluid suitable for ELISA analysis. Of them, 46 patients (48%) were from the oral simvastatin group. Mean tPA and tPA total antigen concentrations in peritoneal fluid were similar between the two groups. Mean PAI-1 and PAI-1 TA concentrations in the statin and placebo group were also similar. Mean PAI-1/tPA complex concentration was similar between the two groups. The number of hospitalizations from SBOs were 5 and 4 in the statin and placebo groups respectively (P = 0.46). The overall mortality at 2-year post-surgery was similar between the two groups (P = 0.59).

CONCLUSIONS

In this pilot study involving humans, oral simvastatin had no measured effect on the peritoneal fibrinolytic pathway in the first 24 h after colorectal surgery. Analysis of clinical outcomes also showed that oral simvastatin did not reduce hospitalizations for SBO in the 2 y after surgery. Further studies may be useful to evaluate whether fibrinolytic pathways beyond 24 h are altered after systemic administration of statins and to evaluate the use of higher doses of statins, perhaps used intraperitoneally rather than systemically.

Usefulness of T2 star-weighted imaging in ovarian cysts and tumors

AIM

The aim of this study was to investigate the prevalence of hypointensity on T2 star-weighted imaging (T2*WI), which is useful for detecting hemosiderin, in endometriomas and other ovarian tumors. The efficacy of detecting adhesions around ovarian tumors was also investigated.

METHODS

Pelvic magnetic resonance (MR) examinations, including T2*WI, were carried out. The inclusion criteria were female patients with ovarian surgical treatments. One hundred seventeen patients with a total of 147 lesions were enrolled. Two radiologists retrospectively evaluated MR imaging (MRI) to predict ovarian pathology and the presence of adhesions. T2*WI hypointensity of the inside and outside along ovarian cysts/tumors was utilized to predict pathological diagnoses and the presence of adhesions, respectively. The kappa scores were calculated to measure interobserver agreement on MRI findings. The MRI interpretations were compared with the results of pathological investigation and surgical observations.

RESULTS

Hypointensity inside along the cyst walls on T2*WI was observed in 100 out of 106 lesions of endometriomas (94.3%), and three out of 41 non-endometrial ovarian cysts/tumors (7.3%). Four different patterns of T2*WI were observed in ovarian cysts/tumors. The kappa score regarding T2*WI hypointensity inside along the cyst walls was 0.633. Using conventional routine pelvic MRI, the sensitivity for detecting adhesions around ovarian cysts was 84.5%. By adding T2*WI, the sensitivity improved to 91.4% (P < 0.01). With conventional methods to predict adhesions, the kappa score was 0.660. After adding T2*WI to the conventional methods, the kappa score was 0.767.

CONCLUSION

Hypointensity on T2*WI was observed frequently in endometrioma. T2*WI also improved the sensitivity for detecting adhesions around ovarian cysts/tumors.

Epidemiology and Prevention of Postsurgical Adhesions Revisited

OBJECTIVE

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Intestinal obstruction secondary to postoperative adhesion formation in abdominal surgery. Review]

The development of intestinal obstruction after upper and lower abdominal surgery is part of the daily life of each every surgeon. Despite this, there are very few good quality studies that allow enable assessment of the frequency of intestinal obstruction to be assessed, even although postoperative adhesions are the cause of considerable direct and indirect morbidity and its prevention can be considered a public health problem. And yet, in Mexico, at this time, there is no validated recommendation validated on the prevention of adhesions, or more particularly, in connection with the use of a variety of anti-adhesion commercial products which have been marketed for at least a decade. Intraperitoneal adhesions develop between surfaces without peritoneum of the abdominal organs, mesentery, and abdominal wall. The most common site of adhesions is between the greater omentum and anterior abdominal wall previous. Despite the frequency of adhesions and their direct and indirect consequences, just there is only one published a recommendation (from gynaecological literature), regarding peritoneal adhesion prevention. As regards of colorectal surgery, performed more than 250,000 colorectal resections are performed annually in the United States, and from 24% to 35% of them will develop a complication. The clinical and economic financial burden of these complications is enormous, and surgeries colorectal surgery been specifically highlighted as a potential point prevention point of surgical morbidity.

An injured tissue affects the opposite intact peritoneum during postoperative adhesion formation

The pathophysiology of adhesion formation needs to be clarified to reduce the adhesion-related morbidity. The epithelial characteristics of the peritoneum suggest a protective role against adhesion formation, yet how the peritoneum is involved in adhesion formation is not well characterized. We microscopically observed an experimental model of adhesion formation to investigate the effects of an injured tissue on the opposite intact peritoneum. Adhesions were induced between injured and intact hepatic lobes, and the intact peritoneum opposite to the injured tissue was examined for 8 days. The opposite intact peritoneum was denuded of mesothelial cells for 6 hours, and the remnant mesothelial cells changed morphologically for 24 hours. The detachment of mesothelial cells allowed fibrin to attach to the basement membrane of the opposite peritoneum, connecting the two lobes. Moreover, macrophages and myofibroblasts accumulated between the two lobes, and angiogenesis occurred from the opposite intact lobe to the injured lobe. These observations indicate that an injured tissue deprives the opposite intact peritoneum of its epithelial structure and causes fibrous adhesions to the opposite intact tissue. This study implies a possible role of mesothelial cells for barrier function against adhesion formation, that is, keeping mesothelial cells intact might lead to its prophylaxis.

Lipoic acid decreases peritoneal adhesion formation in a rat uterine scar model

OBJECTIVE

To investigate the effects of lipoic acid in the prevention of postoperative pelvic adhesions by a visual scoring system and immunohistochemistry in a rat uterine horn model with full thickness injury.

MATERIAL AND METHODS

Twenty-eight female Wistar albino rats were randomised into four groups: uterine trauma control, 15 days and 30 days, and uterine trauma + lipoic acid, 15 days and 30 days. A full thickness defect was established by incising a segment of approximately 1.0 cm in length from each uterine horn, leaving the mesometrium intact. Extension and severity of the adhesions in each group were scored by a visual scoring system and evaluated immunohistochemically.

RESULTS

Adhesion scores were 2.00±0.81, 2.14±0.69 0.71±0.75, and 0.85±0.69 for extent and 2.28±0.48, 2.14±0.69, 0.85±0.69, and 1.14±0.69 for severity in Groups 1, 2, 3 and 4, respectively. Adhesion extent and severity were significantly less for groups treated by lipoic acid but no difference was observed between long and short administration. Both Vitronectin and u-PAR staining were significantly increased in treatment groups when compared to the control group.

CONCLUSION

Lipoic acid was found to be effective in reducing postoperative adhesion formation in a rat model.

In vivo evaluation of in situ polysaccharide based hydrogel for prevention of postoperative adhesion

In this paper, the carboxymethyl chitosan/oxidized dextran hydrogel was developed and its potency application in the prevention of postoperative adhesion was investigated. The developed hydrogel showed porous and interconnected interior structure with pore size about 250 μm, which was sensitive to lysozymic solution (1.5 μg/ml) with almost complete degradation after 4 weeks of in vitro incubation. In vivo study suggested that the developed hydrogel showed the great capacity on the prevention of postoperative adhesions in rat model. According to the result of histopathological examination, it clearly showed that the mesothelial cell layer of abdominal wall and cecum were completely recovered after 7 days of surgery in 3% carboxymethyl chitosan/oxidized dextran hydrogel group, while obvious adhesion between abdominal wall and cecum was observed as treatment with saline solution or 3% carboxymethyl chitosan solution after 1 day of surgery. All these results suggested that the developed biodegradable hydrogel might have potential application in the prevention of postoperative adhesion.

Peritoneal cytokines and adhesion formation in endometriosis: an inverse association with vascular endothelial growth factor concentration

OBJECTIVE

To evaluate inflammatory/angiogenic cytokines-interleukin-1β (IL-1β), IL-6, IL-8, IL-12, interferon-γ (IFN-γ), tumor necrosis factor (TNF), and vascular endothelial growth factor A (VEGF-A)-in the peritoneal fluid of patients with endometriosis in relation to the occurrence and severity of pelvic adhesions and in control women without pelvic pathology.

DESIGN

Case-control study.

SETTING

University research institution and hospital.

PATIENT(S)

Sixty-five women with laparoscopically and histopathologically confirmed endometriosis, including 40 women with pelvic adhesions, and 37 control women without pelvic pathology.

INTERVENTION(S)

Peritoneal fluid aspirated during routine diagnostic laparoscopic examination.

MAIN OUTCOME MEASURE(S)

Cytokines evaluated in the peritoneal fluid via specific enzyme-linked immunosorbent assays.

RESULT(S)

Endometriosis and the revised American Fertility Society score of this disease were associated with statistically significantly increased levels of peritoneal IL-6 and IL-8 whereas the incidence and score of endometriosis-related pelvic adhesions were negatively associated with increased levels of VEGF-A. Notably, the concentration of VEGF-A predicted adhesion development and severity after adjustment for endometriosis severity. The adhesion score also correlated with increased levels of IL-6; however, after adjustment for endometriosis severity, the effect of this cytokine was no longer statistically significant.

CONCLUSION(S)

Increased levels of VEGF-A may be associated with a decreased rate of pelvic adhesion formation in the course of endometriosis.