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

Light-Operated Transient Unilateral Adhesive Hydrogel for Comprehensive Prevention of Postoperative Adhesions

Dislocation of anti-adhesion materials, non-specific tissue adhesion, and the induction of secondary fibrinolysis disorders are the main challenges faced by postoperative anti-adhesion materials. Herein, a self-leveling transient unilateral adhesive hydrogel is custom-designed to conquer these challenges with a theoretically calculated and dual-step tailored gellan gum (GG) as the sole agent. First, the maximum gelation temperature of GG is lowered from 42-25 °C through controlled perturbation of intra- and inter-molecular hydrogen bonds, which is achieved by employing the methacrylic anhydride as a "hydrogen bond's perturbator" to form methacrylate GG (MeGG). Second, the "self-leveling" injectability and wound shape adaptably are endowed by the formation of borate-diol complexed MeGG (BMeGG). Finally, the transient unilateral tissue-adhesive hydrogel (BMeGG-H) barrier is prepared through photo-controlled cross-linking of reactive alkenyl groups. This degradable hydrogel demonstrates favorable rheological properties, light-controlled unilateral adhesion properties, biocompatibility, anti-fibrin adhesion, and anti-cell adhesion properties in vitro. Comprehensive regulation of the fibrinolysis balance toward non-adhesion is conformed in a rat model after intra-abdominal surgery via anti-autoinflammatory response, intestinal wall integrity repair, and Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) balance adjustment. Notably, the 14th day anti-adhesion effective rate is 100%, indicating its significant potential in clinical applications for postoperative anti-adhesion.

Avastin-Loaded 3D-Printed Alginate Scaffold as an Effective Antiadhesive Barrier to Prevent Postsurgical Adhesion Bands Formation

Postoperative adhesion can cause complications, such as pain and organ blockage, in the abdominal regions. To address this issue, surgical techniques and antiadhesive treatments are applied. Given the significant role of vascularization in adhesion band formation, Avastin (Ava) that targets vascular endothelial growth factor (VEGF) can be applied to prevent peritoneal adhesion bands. Moreover, Alginate (Alg), a natural polysaccharide, is a promising physical barrier to prevent adhesion bands. Incorporating Ava into Alg hydrogel in a form of 3D-printed scaffold (Alg/Ava) has potential to suppress inflammation and angiogenesis, leading to reduce peritoneal adhesion bands. Following physical, morphological, and biocompatibility evaluations, the efficacy of Alg and Ava alone and their combination in Alg/Ava on the formation of postsurgical adhesions is evaluated. Upon confirming physical stability and sustained release of Ava, the Alg/Ava scaffold effectively diminishes both the extent and strength of adhesion bands. Histopathological examination shows that the reduction in fibrosis and inflammation is responsible for preventing adhesion bands by the Alg/Ava scaffold. Additionally, the cytokine assessment reveals that this is due to the inhibition in the secretion of VEGF and Interleukin 6 suppressing vascularization and inflammatory pathways. This study suggests that a 3D-printed Alg/Ava scaffold has great potential to prevent the postsurgical adhesion bands.

Research landscape of abdominal adhesions from 2004 to 2023: A bibliometric analysis

Adhesions are the most common complication of abdominal or pelvic surgery and remain a challenging problem. To better understand the development tendency of abdominal adhesions, we performed a comprehensive bibliometric analysis of the field of abdominal adhesions. In total, 2219 articles regarding abdominal adhesions were screened and analyzed from 3410 manuscripts indexed in the Web of Science-indexed manuscripts regarding abdominal adhesion from 2004 to 2023. A bibliometric analysis was performed, and CiteSpace [version 6.2. R3 (64-bit)] and VOSviewer (version 1.6.19) were used to visualize the results. The number of annual publications showed slight growth before 2019, and the USA contributed the most publications. The most prolific author in this domain was Diamond, while the publications from Ten Broek had the strongest influence. The most popular journal in this field was the Journal of Surgical Research, and the most frequently co-cited journal was Fertility and Sterility. After analyzing the keywords, "prevention", "surgery" and "peritoneal adhesion" were the 3 most co-cited keywords, while "adhesive small bowel obstruction" was the strongest keyword in the citation burst. Here, for the first time, we used bibliometric methods to study abdominal adhesions over the past ten years. By summarizing the characteristics of publications and predicting future research prospects, we established a framework for researchers and provided a basis for subsequent research.

Awareness of Anti-adhesive Barriers Among Surgeons in Saudi Arabia

Introduction Post-operative adhesions present a number of difficulties, including intestinal obstruction and infertility, and they frequently require readmission due to adhesion-related problems. Notwithstanding these ramifications, there are surprisingly few thorough national surveys that address surgeons' awareness of adhesives. By assessing Saudi surgeons' knowledge of post-operative adhesions and their use of anti-adhesive medications, this study aims to close this knowledge gap. Methods This study is a cross-sectional observational research study aimed at Saudi Arabian surgeons utilizing a self-administered, semi-structured online questionnaire. The questionnaire was distributed to participants via social media and in-person email using basic random selection. It included adhesion morbidity and prevalence, pre-operative informed consent issues, adhesion preventive viewpoints, and anti-adhesive chemical use. Results There were 111 participants in total, of 41% were experienced surgeons with more than five years of experience. According to the survey, the majority of surgeons occasionally employed anti-adhesive compounds, especially during laparotomies (28%), and 38% never used them during laparoscopies. The study found that participants varied in what they informed patients regarding adhesion complications: 25% of participants informed 5%-10% of the patients about the possible adhesion complications in laparotomy procedures, whereas 26% of participants informed 10-25% of the patients in laparoscopic procedures. Compared with their specialist peers, general surgeons agreed more on the clinical significance of adhesions and prevention. Notably, three-quarters of participants were unclear about when to use anti-adhesive compounds. Conclusion While acknowledging the clinical significance of post-operative adhesions and recognizing the potential for prevention, most surveyed surgeons did not include adhesions as a post-operative complication in informed consent. The study underscores a belief in the efficacy of anti-adhesives yet reveals a widespread lack of clarity regarding specific indications for their use. Recommendations include implementing educational sessions during surgical training to heighten awareness of adhesions as a major post-operative complication and to encourage the appropriate utilization of available barriers and pharmacological anti-adhesive products.

Advanced postoperative tissue antiadhesive membranes enabled with electrospun nanofibers

Tissue adhesion is one of the most common postoperative complications, which is frequently accompanied by inflammation, pain, and even dyskinesia, significantly reducing the quality of life of patients. Thus, to prevent the formation of tissue adhesions, various strategies have been explored. Among these methods, placing anti-adhesion membranes over the injured site to separate the wound from surrounding tissues is a simple and prominently favored method. Recently, electrospun nanofibers have been the most frequently investigated antiadhesive membranes due to their tunable porous structure and high porosities. They not only can act as an essential barrier and functional carrier system but also allow for high permeability and nutrient transport, showing great potential for preventing tissue adhesion. Herein, we provide a short review of the most recent applications of electrospun nanofibrous antiadhesive membranes in tendons, the abdominal cavity, dural sac, pericardium, and meninges. Firstly, each section highlights the most representative examples and they are sorted based on the latest progress of related research. Moreover, the design principles, preparation strategies, overall performances, and existing problems are highlighted and evaluated. Finally, the current challenges and several future ways to develop electrospun nanofibrous antiadhesive membranes are proposed. The systematic discussion and proposed directions can shed light on ideas and guide the reasonable design of electrospun nanofibrous membranes, contributing to the development of exceptional tissue anti-adhesive materials in the foreseeable future.

Establishment of a risk prediction model for bowel preparation failure prior to colonoscopy

BACKGROUND

This study aimed to determine the factors that contribute to the failure of bowel preparation in patients undergoing colonoscopy and to develop a risk prediction model.

METHODS

A total of 1115 outpatients were included. Patients were randomly divided into two groups: the modeling group (669 patients) and the validation group (446 patients). In the modeling group, patients were further divided into two groups based on their success and failure in bowel preparation using the Boston Bowel Preparation Scale. A logistic regression analysis model was used to determine the risk factors of bowel preparation failure, which was subsequently visualized using an alignment diagram.

RESULTS

After controlling for relevant confounders, multifactorial logistic regression results showed that age ≥ 60 years (OR = 2.246), male (OR = 2.449), body mass index ≥ 24 (OR = 2.311), smoking (OR = 2.467), chronic constipation (OR = 5.199), diabetes mellitus (OR = 5.396) and history of colorectal surgery (OR = 5.170) were influencing factors of bowel preparation failure. The area under the ROC curve was 0.732 in the modeling group and 0.713 in the validation group. According to the calibration plot, the predictive effect of the model and the actual results were in good agreement.

CONCLUSIONS

Age ≥ 60 years, male, body mass index ≥ 24, smoking, chronic constipation, diabetes mellitus, and history of colorectal surgery are independent risk factors for bowel preparation failure. The established prediction model has a good predictive efficacy and can be used as a simple and effective tool for screening patients at high risk for bowel preparation failure.

The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040: Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources

Polysaccharides are among the most abundant bioresources on earth and consequently need to play a pivotal role when addressing existential scientific challenges like climate change and the shift from fossil-based to sustainable biobased materials. The Research Roadmap 2040 of the European Polysaccharide Network of Excellence (EPNOE) provides an expert's view on how future research and development strategies need to evolve to fully exploit the vast potential of polysaccharides as renewable bioresources. It is addressed to academic researchers, companies, as well as policymakers and covers five strategic areas that are of great importance in the context of polysaccharide related research: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Chemistry, Biology & Physics, and (V) Skills & Education. Each section summarizes the state of research, identifies challenges that are currently faced, project achievements and developments that are expected in the upcoming 20 years, and finally provides outlines on how future research activities need to evolve.

Quercetin inhibits mesothelial-mesenchymal transition and alleviates postoperative peritoneal adhesions by blocking the TGF-β1/PI3K/AKT pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Carthami flos is a dried flower of the Asteraceae plant Carthamus tinctorius (L.). Danhong injection, composed of Carthami flos and Danshen can prevent the formation of postoperative peritoneal adhesions. Quercetin (QUE), an active compound of Carthami flos, has also been proved to prevent postoperative abdominal and uterine cavity adhesions. However, whether QUE is the key component in Carthami flos and the mechanism in preventing postoperative peritoneal adhesions has not been studied.

AIM OF THE STUDY

To predict whether QUE is the key molecule in Carthami flos and explore the effect and mechanism of QUE in preventing postoperative peritoneal adhesions.

MATERIALS AND METHODS

Drug composition and target analysis was used to predict the key component in Carthami flos. The method of cecum-sidewall abrasion was used to establish adhesion models, and the antiadhesion effect of QUE was evaluated with the adhesion scoring system. Network pharmacology was used to predict the targets and potential mechanism of QUE in preventing adhesion. The mechanism was further verified by immunofluorescence, Western blot, wound healing experiment, and molecular docking.

RESULTS

Quercetin was predicted to be the key to preventing postoperative peritoneal adhesions in Carthami flos. Animal experiments revealed that QUE effectively ameliorated adhesions and reduced the expression of mesothelial-mesenchymal transition (MMT) related markers and TGF-β1. Moreover, the TGF-β1/PI3K/AKT pathway was predicted via protein-protein interaction and Kyoto encyclopedia of Genes and Genomes enrichment analysis to play a crucial part in preventing adhesion by QUE. Furthermore, in vitro experiments and molecular docking demonstrated that QUE could block the TGF-β1/PI3K/AKT pathway through forming a stable combination with TβR-II, thereby inhibiting MMT and ameliorating peritoneal adhesion.

CONCLUSIONS

QUE can not only reduce postoperative TGF-β1 but also block the TGF-β1/PI3K/AKT pathway to inhibit MMT of mesothelial cells, and finally alleviate postoperative peritoneal adhesions. These findings may provide insights towards development of a safe and effective anti-adhesive drug for prevention of postoperative peritoneal adhesions.

Transvaginal extraperitoneal single-port laparoscopic sacrocolpopexy for apical prolapse after total/subtotal hysterectomy: Chinese surgeons' initial experience

BACKGROUND

To introduce a novel technique of transvaginal extraperitoneal single-port laparoscopic sacrocolpopexy (ESLS) for apical prolapse and to evaluate the feasibility and short-term outcomes of this technique.

METHODS

Sixteen patients were enrolled to undergo ESLS between January 2020 and May 2021. Perioperative outcomes were included. Short-term results were assessed by Pelvic Floor Distress Inventory-20 (PFDI-20), Pelvic Organ Prolapse Quantification (POP-Q) scores, mesh exposure and prolapse recurrence.

RESULTS

A total of 14/16 cases (87.5%) were successfully completed. The mean operation time was 118 min (range 85-160), and the mean blood loss was 68 ml (range 20-100). The mean postoperative visual analog scale (VAS) pain score at 24 h was 0.7. No intraoperative complications occurred except for one patient who developed subcutaneous emphysema. All patients gained a significant improvement in both physical prolapse and quality of life at 12 months after surgery, and there was no mesh exposure or prolapse recurrence.

CONCLUSIONS

Our experience showed that transvaginal ESLS is a feasible and effective technique for apical prolapse with a previous hysterectomy. However, this technique should be performed by surgeons with extensive experience both in vaginal surgery and laparoscopic single-port surgery.

Biocompatible Nanocomposites for Postoperative Adhesion: A State-of-the-Art Review

To reduce and prevent postsurgical adhesions, a variety of scientific approaches have been suggested and applied. This includes the use of advanced therapies like tissue-engineered (TE) biomaterials and scaffolds. Currently, biocompatible antiadhesive constructs play a pivotal role in managing postoperative adhesions and several biopolymer-based products, namely hyaluronic acid (HA) and polyethylene glycol (PEG), are available on the market in different forms (e.g., sprays, hydrogels). TE polymeric constructs are usually associated with critical limitations like poor biocompatibility and mechanical properties. Hence, biocompatible nanocomposites have emerged as an advanced therapy for postoperative adhesion treatment, with hydrogels and electrospun nanofibers among the most utilized antiadhesive nanocomposites for in vitro and in vivo experiments. Recent studies have revealed that nanocomposites can be engineered to generate smart three-dimensional (3D) scaffolds that can respond to different stimuli, such as pH changes. Additionally, nanocomposites can act as multifunctional materials for the prevention of adhesions and bacterial infections, as well as tissue healing acceleration. Still, more research is needed to reveal the clinical potential of nanocomposite constructs and the possible success of nanocomposite-based products in the biomedical market.

A Zwitterionic Hydrogel with Anti-Oxidative and Anti-Inflammatory Properties for the Prevention of Peritoneal Adhesion by Inhibiting Mesothelial-Mesenchymal Transition

Postoperative peritoneal adhesion is a serious clinical complication. Various hydrogel barriers have been developed to prevent peritoneal adhesion. However, it remains a challenge to design a hydrogel with desirable physicochemical properties and bioactivities. In this study, a zwitterionic polysaccharide-based multifunctional hydrogel is developed using epigallocatechin-3-gallate (EGCG) to prevent postoperative abdominal adhesion. This hydrogel is simple to use and has desirable properties, such as excellent injectability, self-healing, and non-swelling properties. The hydrogel also has ultralow fouling capabilities, such as superior bactericidal performance, cell and protein adhesion, and low immunogenicity resistance. Moreover, the hydrogel exhibits good antioxidant activity, which is attributed to the integration of EGCG. Furthermore, the detailed mechanism from in vivo and in vitro experimental studies illustrates that hydrogel compositions can synergistically prevent adhesion formation through multiple pathways, including anti-inflammatory and antioxidant capabilities and inhibition effects on the mesothelial-mesenchymal transition (MMT) process induced by transforming growth factor (TGF-β). In summary, this zwitterionic multifunctional hydrogel has great potential to prevent postoperative adhesion formation in the clinical setting.

Irritable Bowel Syndrome-Like Symptoms in Quiescent Inflammatory Bowel Disease: A Practical Approach to Diagnosis and Treatment of Organic Causes

BACKGROUND

Despite achieving remission in inflammatory bowel disease (IBD), persistent gastrointestinal symptoms are common in quiescent IBD. While irritable bowel syndrome (IBS) is commonly diagnosed in IBD, IBS-like symptoms of recurrent abdominal pain and altered bowel habits can also be attributed to a wide range of overlapping gastrointestinal (GI) etiologies and systemic disorders with GI manifestations that often do not respond to conventional IBS therapies. Delay in diagnosis of these conditions can lead to ongoing patient suffering, reduced quality of life, repetition of invasive testing, increased healthcare utilization, and potentially unnecessary empirical escalation of IBD-related treatments.

AIMS

This review provides a practical approach for the evaluation and diagnosis of IBS mimickers in IBD. We summarize the definition, pathophysiology, diagnosis and treatment of the potential etiologies causing unexplained GI symptoms.

CONCLUSION

Overlapping conditions can co-exist with IBD and explain IBS-like symptoms. The diagnostic work-up in this population should be individualized and tailored to the predominant symptom pattern, associated clinical signs and symptoms and predisposing conditions that can be obtained from a detailed history and physical examination.

Efficacy and safety of purified starch for adhesion prevention in colorectal surgery

Background

Adhesions within the abdominal cavity develop in as many as 90 % of individuals following abdominal surgery. However, the true adhesive condition of patients can only be ascertained during the second surgery.

Methods

We conducted a prospective, non-randomized study to assess the anti-adhesion properties of purified starch in patients who had undergone colorectal surgery in the past and then needed a subsequent surgical intervention. Adhesion scores have been prospectively recorded in operation notes since January 2020 when patients underwent a second surgery. Patients who had received purified starch during their initial surgery constituted the purified starch group, while those who had not received anti-adhesion medical materials were the control group. The main objectives of the study were to evaluate the extent and severity of adhesions as primary outcomes, while secondary outcomes included measuring blood loss, operation time, and postoperative complications.

Results

We analyzed the data of 101 patients, with 61 in the purified starch group and 40 in the control group. In multivariate analysis, adhesion severity (Odds ratio, 0.20, 95 % confidence interval 0.08-0.54, P < 0.01) and adhesion area scores (Odds ratio, 0.13, 95 % confidence interval 0.04-0.45, P < 0.01) were significantly lower in the purified starch group than in the control group. There was no significant difference in operation times, blood loss, and postoperative complications between the two groups.

Conclusion

Purified starch is a safe and effective anti-adhesion material that can significantly reduce the severity and extent of adhesion after colorectal surgery.

The Role of Prophylactic and Adjuvant Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in Prevention of Peritoneal Metastases in Advanced Colorectal Cancer

Hyperthermic intraperitoneal chemotherapy (HIPEC) is a locoregional therapy that may be combined with cytoreductive surgery (CRS) to treat patients with colorectal cancer and peritoneal metastases (PM). In recent years, three randomized controlled trials (RCTs) have investigated the role of prophylactic or adjuvant HIPEC in preventing the development of PM in patients with high-risk colorectal cancer: PROPHYLOCHIP and COLOPEC evaluated adjuvant HIPEC, and HIPECT4 studied concurrent HIPEC and CRS. Although PROPHYLOCHIP and COLOPEC were negative trials, a great deal may be learned from their methodology, outcome measures, and patient selection criteria. HIPECT4 is the first RCT to show a clinical benefit of HIPEC in high-risk T4 colorectal cancer, demonstrating improved locoregional disease control with the addition of HIPEC to CRS with no increase in the rate of complications. This review critically examines the strengths and limitations of each major trial and discusses their potential impact on the practice of HIPEC. Several additional ongoing clinical trials also seek to investigate the role of HIPEC in preventing PM in advanced colorectal cancer.

Carbon monoxide (CO) derived from the CO-releasing molecule CORM-2 reduces peritoneal adhesion formation in a rat model

BACKGROUND

Although low-dose carbon monoxide (CO) administration has been shown to have an anti-fibrotic effect in various fibrotic diseases, its effects on peritoneal adhesion (PA), one of the postoperative complications, are not elucidated. In this study, the effect of CO-releasing tricarbonyldichlororuthenium (II) dimer (CORM-2) administration on the formation of PA and the underlying factors of its potential effect were investigated.

METHODS AND RESULTS

After the induction of PA, rats were divided into four groups with 8 rats in each group. The rats received either (i) dimethyl sulfoxide:saline solution (1:10) as a vehicle, (ii) 2.5 mg/kg CORM-2, (iii) 5 mg/kg CORM-2, or (iv) inactive (i) CORM (iCORM) intragastrically every day for a duration of 7 days. PA was not induced in rats (n = 8) designated as sham controls. Gross, histological, immunohistochemical and quantitative real-time polymerase chain reaction analyses were performed to evaluate the effectiveness of CORM-2 administration. Gross analysis showed that CORM-2 administration reduced PA formation compared to rats treated with vehicle. Histological and immunohistochemical examinations showed that increased collagen deposition, myofibroblast accumulation, microvessel density, and M1 macrophage count in the peritoneal fibrosis area of vehicle-treated rats decreased following CORM-2 treatments. PCR analyses showed that CORM-2 treatments decreased hypoxia-induced Hif1a, profibrotic Tgfb1, ECM components Col1a1 and Col3a1, collagen degradation suppressor Timp1, fibrinolysis inhibitor Serpine1, and pro-inflammatory Tnf mRNA expressions, while increasing the M2 macrophage marker Arg1 mRNA expression.

CONCLUSIONS

These results suggested that CORM-2 administration reduces PA formation by affecting adhesiogenic processes such as pro-inflammatory response, fibrinolytic system, angiogenesis and fibrogenesis.

Analysis of abdominal adhesion using the ileostomy model

Abdominal adhesion occurs commonly in clinical practice, causing unfavorable symptoms and readmission. The ileostomy operation is a common surgical procedure and we utilized this model to evaluate abdominal adhesion. Adhesion grade score was calculated in 35 patients (Cohort 1) and subjected to correlation and receiver operating characteristic analysis. Then 98 consecutive patients (Cohort 2) who underwent ileostomy and ileostomy closure were included into a retrospective study. Logistic regression analysis was performed, and the risk of small bowel obstruction was also assessed. The time of ileostomy closure correlated with adhesion grade score in Cohort 1, justifying its use as an indicator of abdominal adhesion. All patients in Cohort 2 were then divided into the high- and low-adhesion group. A multi-variable logistic regression analysis indicated that type of surgery and peritoneum suture during ileostomy were significant factors affecting the risk of abdominal adhesion. Abdominal adhesion had the trend to prolong the length of stay postoperatively without increasing the risk of bowel obstruction. Nine patients suffered bowel obstruction, and age older than 65 significantly increased the risk. We proposed the ileostomy procedure to be a model of abdominal adhesion, and the operative time of ileostomy closure could be used as an alternative of adhesion score. Type of surgery and peritoneum suture may be risk factors of abdominal adhesion. Older age increased the risk of small bowel obstruction after ileostomy surgery.

Polyvinylpyrrolidone-Alginate Film Barriers for Abdominal Surgery: Anti-Adhesion Effect in Murine Model

Surgical operations on the peritoneum are often associated with the formation of adhesions, which can interfere with the normal functioning of the internal organs. The effectiveness of existing barrier materials is relatively low. In this work, the effectiveness of soluble alginate-polyvinylpyrrolidone (PVP-Alg) and non-soluble Ca ion cross-linked (PVP-Alg-Ca) films in preventing these adhesions was evaluated. Experiments in vivo were performed on mice via mechanical injury to the adjacent peritoneum wall and the caecum, followed by the application of PVP-Alg or PVP-Alg-Ca films to the injured area. After 7 days, samples from the peritoneal wall and caecum were analyzed using histology and quantitative polymerase chain reaction (qPCR). It was shown that the expression of genes responsible for adhesion formation in the caecum in the PVP-Alg group was comparable to that in the control group, while in the PVP-Alg-Ca group, it increased by 5-10 times. These results were consistent with the histology: in the PVP-Alg group, the adhesions did not form, while in the PVP-Alg-Ca group, the adhesions corresponded to five points on the adhesion scale. Therefore, the formation of intraperitoneal adhesions can be effectively prevented by non-crosslinked, biodegradable PVP-Alg films, whereas cross-linked, not biodegradable PVP-Alg-Ca films cause inflammation and adhesion formation.

Two-point fixation enhanced the outcome of laparoscopy-assisted ventriculoperitoneal shunt in adult patients with hydrocephalus: a retrospective study

Objective

In patients with hydrocephalus, laparoscopy significantly improved ventriculoperitoneal shunt (VPS) outcomes. However, abdominal complications still occur, which require revision surgeries. In this study, we aimed to examine whether laparoscopy-assisted VPS with two-point fixation (LAVPS-TPF) has better outcomes than those of VPS (open-VPS) and laparoscopy-assisted VPS with no fixation (LAVPS-NF).

Methods

We retrospectively reviewed clinical records of 105 open-VPS, 40 LAVPS-NF, and 49 LAVPS-TPF cases from 2015 to 2020. Data including body mass index, etiology, abdominal surgery history, Glasgow coma scale (GCS), operation time, in-hospital days, shunt failure, complications, and modified Rankin scores were analyzed, as well as subgroups of patients with history of abdominal surgery, GCS scores, and revision surgeries.

Results

The LAVPS-TPF group demonstrated decreased shunt failure rates at 12 months (2.04%) compared to those of the open-VPS group (14.29%, P = 0.020) and reduced abdominal shunt-related complications (P = 0.004 vs. open-VPS and LAVPS-NF) and shunt revisions. In the LAVPS-TPF group with abdominal history (n = 51), 12-month shunt failure rates (P = 0.020 vs. open-VS), repair frequency (P = 0.020 vs. open-VS), and abdominal complications (P = 0.003 and 0.006 vs. open-VS and LAVPS-NF) were reduced. In the LAVPS-TPF group with GCS scores of 13-15 (n = 152), shunt failure rates at 12 months, abdominal complications, and revision frequency were decreased (P < 0.05 vs. other groups). Compared to the LAVPS-NF group, neurological complications were also reduced (P = 0.001). Among revision surgeries (n = 28), fixed shunts resulted in improved shunt survival rates at 12 months, reduced abdominal complications, and secondary revisions (P < 0.05). Moreover, a more optimal recovery without neurological sequelae was achieved by shunt fixation than that by LAVPS-NF (P < 0.01).

Conclusions

LAVPS-TPF significantly improved shunt survival rates at 12 months and reduced the incidence of abdominal shunt-related complications compared to open-VPS and LAVPS-NF, especially in patients with history of abdominal surgery, higher GCS scores, and revision surgeries. However, further studies are required to confirm these benefits.

Research on Mechanisms of Chinese Medicines in Prevention and Treatment of Postoperative Adhesion

Postoperative adhesion (PA) is currently one of the most unpleasant complications following surgical procedures. Researchers have developed several new strategies to alleviate the formation of PA to a great extent, but so far, no single measure or treatment can meet the expectations and requirements of clinical patients needing complete PA prevention. Chinese medicine (CM) has been widely used for thousands of years based on its remarkable efficacy and indispensable advantages CM treatments are gradually being accepted by modern medicine. Therefore, this review summarizes the formating process of PA and the efficacy and action mechanism of CM treatments, including their pharmacological effects, therapeutic mechanisms and advantages in PA prevention. We aim to improve the understanding of clinicians and researchers on CM prevention in the development of PA and promote the in-depth development and industrialization process of related drugs.

The effect of natural surfactants on the development of postoperative intraabdominal adhesion

Background/aim

The development of postoperative adhesion after abdominal surgery is sometimes a severe problem. Our study investigates the effectiveness of exogenous surfactant application in preventing adhesion development in the experimental adhesion model.

Materials and methods

This randomized-controlled interventional study was carried out in the animal laboratory of Kahramanmaraş Sütçü İmam University between March 1 and March 31, 2020. An experimental intra-abdominal adhesion model was established in 24 adult female rats by cecal abrasion. Rats were randomly divided into four groups. Groups I, II, and III were taken intraperitoneally as beractant, poractant, and calfactant applied groups, respectively. Group IV was the control group. Relaparotomy was performed in all groups on the 15th postoperative day, and intra-abdominal adhesions were scored macroscopically according to the Canbaz scoring system. In addition, the cecal regions were evaluated microscopically and scored according to the Zühlke microscopic classification system. The scores of the groups were compared statistically.

Results

The Zühlke adhesion development score was significantly lower in the exogenous surfactant applied groups. In addition, when the surfactant-applied groups were compared among themselves, it was seen that the adhesion score in the beractant group was significantly better than the other surfactant types (p < 0.01).

Conclusion

Our study results showed that prophylactic intraperitoneal surfactant application significantly reduced postoperative adhesion development, particularly beractant.

An Overview of Postoperative Intraabdominal Adhesions and Their Role on Female Infertility: A Narrative Review

Postoperative intraabdominal adhesions can occur after more than 90% of gynecologic surgeries. They not only cause chronic pelvic pain and small bowel obstruction, but are also one of the main reasons for infertility. Adhesions are not only a burden for the affected patients, but are also a burden for the healthcare system, since the treatment of adhesion-associated complications costs a considerable amount of money. The gold standard for the diagnosis of adhesions is by laparoscopy, although other methods, such as transvaginal hydro-laparoscopy, are being discussed as better alternatives. Ideally, adhesions are avoided inherently, by operating carefully and by using microsurgical principles. If this is not possible, gel barriers have been shown to be successful in reducing postoperative adhesions.

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.

Ultrasound assessment of abdominal adhesions in neonates: data over dogma for re-operative timing

INTRODUCTION

Neonatal abdominal reoperation is difficult and can be complicated by abdominal adhesions. Identifying patients who could safely undergo early reoperation would save TPN and central line days, decrease associated infection and liver injury, and NICU and hospital length of stay. We sought to determine if ultrasound (US) could accurately assess the location and severity of adhesions in neonates as an objective dynamic marker capable of informing reoperation timing.

METHODS

After IRB approval, we conducted a prospective observational study including neonates undergoing abdominal operations. Patients received surgeon-performed US approximately every 2 weeks until reoperation or discharge. Adhesions were assessed in five zones: right upper quadrant (RUQ), right lower quadrant (RLQ), left upper quadrant (LUQ), left lower quadrant (LLQ) and peri-incision (INC).

RESULTS

Over a 6-month study period, 16 neonates were enrolled. Median gestational age was 34 weeks at birth and median weight 2.2 kg. 6 underwent reoperation within initial NICU admission. At time of operation US correctly identified the absence or presence and severity of adhesions in: RUQ (3/3); RLQ (6/6); LUQ (4/5); LLQ (6/6); and INC (5/5).

CONCLUSION

US can identify location and severity of post-operative adhesions in neonates, potentially identifying patients who can safely undergo reoperation earlier than predetermined wait periods.

LEVEL OF EVIDENCE

IV.

The preventive effect of omega-3 fish oil on the formation of peritoneal adhesions

<br><b>Introduction:</b> Postoperative peritoneal adhesions that form after abdominal surgery still continue to exist as an unresolved health problem.</br> <br><b>Aim:</b> The aim of the study is to examine whether omega-3 fish oil has a preventive effect on postoperative peritoneal adhesions.</br> <br><b>Material and methods:</b> Twenty-one female Wistar albino rats were separated into 3 groups (sham, control and experimental), each consisting of 7 rats. In the sham group, only laparotomy was performed. In both the control and experimental group rats, the right parietal peritoneum and cecum were traumatised to form petechiae. Following this procedure, the abdomen was irrigated with omega-3 fish oil in the experimental group. The rats were re-explored on the 14^th postoperative day and any adhesions were scored. Tissue samples and blood samples were taken for histopathological and biochemical analysis.</br> <br><b>Results:</b> None of the rats that were administered omega-3 fish oil developed macroscopic postoperative peritoneal adhesions (P = 0.005). The omega-3 fish oil formed an anti-adhesive lipid barrier on the injured tissue surfaces. Microscopic evaluation revealed diffuse inflammation with excessive connective tissue and fibroblastic activity in the control group rats, while foreign body reactions were common in the omega-3 rats. The mean amount of hydroxyproline in samples from injured tissues was significantly lower in the omega-3 rats than in the control rats (P = 0.004).</br> <br><b>Conclusion:</b> Intraperitoneal application of omega-3 fish oil prevents postoperative peritoneal adhesions by forming an anti-adhesive lipid barrier on injured tissue surfaces. However, further studies are needed to determine whether this adipose layer is permanent or will be resorbed over time.</br>.

The Controlled Release and Prevention of Abdominal Adhesion of Tannic Acid and Mitomycin C-Loaded Thermosensitive Gel

Postoperative abdominal adhesion is one of the most common complications after abdominal surgery. A single drug or physical barrier treatment does not achieve the ideal anti-adhesion effect. We developed a thermosensitive hydrogel (PPH hydrogel) consisting of poloxamer 407 (P407), poloxamer (P188), and hydroxypropyl methylcellulose (HPMC) co-blended. An injectable thermosensitive TA/MMC-PPH hydrogel was obtained by loading tannic acid (TA) with an anti-inflammatory effect and mitomycin C (MMC), which inhibits fibroblast migration or proliferation. The optimal prescriptions of PPH hydrogels with a suitable gelling time (63 s) at 37 °C was 20% (w/v) P407, 18% (w/v) P188, and 0.5% (w/v) HPMC. The scanning electron microscopy (SEM) revealed that the PPH hydrogel had a three-dimensional mesh structure, which was favorable for drug encapsulation. The PPH hydrogel had a suitable gelation temperature of 33 °C, a high gel strength, and complicated viscosity at 37 °C, according to the rheological analysis. In vitro release studies have shown that the PPH hydrogel could delay the release of TA and MMC and conform to the first-order release rate. Anti-adhesion tests performed on rats in vivo revealed that TA/MMC-PPH hydrogel significantly reduced the risk of postoperative adhesion. In conclusion, the TA/MMC-PPH hydrogel prepared in this study showed an excellent performance in both controlled drug release and anti-adhesive effects. It can be used as a protocol to prevent or reduce postoperative abdominal adhesion.

The risk of subsequent surgery following bowel resection for Crohn's disease in a national cohort of 19 207 patients

AIM

Surgery is required for most patients with Crohn's disease (CD) and further surgery may be necessary if medical treatment fails to control disease activity. The aim of this study was to characterize the risk of, and factors associated with, further surgery following a first resection for Crohn's disease.

METHODS

Hospital Episode Statistics from England were examined to identify patients with CD and a first recorded bowel resection between 2007 and 2016. Multivariable logistic regression was used to examine risk factors for further resectional surgery within 5 years. Prevalence-adjusted surgical rates for index CD surgery over the study period were calculated.

RESULTS

In total, 19 207 patients (median age 39 years, interquartile range 27-53 years; 55% women) with CD underwent a first recorded resection during the study period. 3141 (16%) underwent a further operation during the study period. The median time to further surgery was 2.4 (interquartile range 1.2-4.6) years. 3% of CD patients had further surgery within 1 year, 14% by 5 years and 23% by 10 years. Older age (≥58), index laparoscopic surgery and index elective surgery (adjusted OR 0.65, 95% CI 0.54-0.77; 0.77, 0.67-0.88; and 0.77, 0.69-0.85; respectively) were associated with a reduced risk of further surgery by 5 years. Prior surgery for perianal disease (1.60, 1.37-1.87), an extraintestinal manifestation of CD (1.51, 1.22-1.86) and index surgery in a high-volume centre for CD surgery (1.20, 1.02-1.40) were associated with an increased risk of further surgery by 5 years. A 25% relative and 0.3% absolute reduction in prevalence-adjusted index surgery rates for CD was observed over the study period.

CONCLUSIONS

Further surgery following an index operation is common in CD. This risk was particularly seen in patients with perianal disease, extraintestinal manifestations and those who underwent index surgery in a high-volume centre.

NFK prevent postoperative abdominal adhesion through downregulating the TGF-β1 signaling pathway

BACKGROUND

Postoperative abdominal adhesions (PAAs) represent a frequent condition occurring in more than 90% of patients undergoing abdomen and pelvic surgeries, which can cause chronic abdominal pain, female infertility, and repeated bowel obstruction, requiring repetitive surgical interventions causing morbidity and mortality, as well as high costs. It is therefore of paramount clinical importance and significance to develop practical and reliable strategies for preventing the occurrence of PAAs.

METHODS AND RESULTS

In this study, we demonstrated that Nianfukang (NFK, composed of polyethylene glycol 1450 and diclofenac sodium) is highly effective in preventing PAAs, likely by reducing leukocytes and inflammatory factors in the abdominal cavity, and inhibiting intestinal fibrosis in a rat model of PAAs induced by postoperative cecum scraping. We further uncovered that NFK downregulates the expression of TGF-β1, a key factor for adhesion formation, to suppress the TGF-β1/TGF-βRIII/Smad2 signaling pathway, thereby inhibiting the proliferation and migration of fibroblasts and provided evidences for the involvement of the TGF-β1/TGF-βRIII/Smad2 axis in the prevention of PAAs in normal human colon fibroblast CCD-18Co.

CONCLUSIONS

Our findings support NFK as a potential anti-adhesive product that has the advantages of significant effectiveness, safety profile, and low cost, as well as clear mechanism of action.

Can serum tumor necrosis factor-alpha predict peritoneal adhesions prior to secondary laparoscopic procedures?

AIM OF THE STUDY

This study aimed to investigate the incidence and degree of postoperative intra-abdominal adhesions(POAs) in secondary laparoscopic procedures and assess the power of the preoperative levels of tumor necrosis factor-alpha(TNF-α) and interleukin-1 beta(IL-1β) and selected peripheral inflammatory biomarkers(PIBs) in the prediction of the development and extent of POA.

PATIENTS AND METHODS

This prospective study enrolled 103 patients who had previously undergone at least one or more laparoscopic abdominal or gynecological operations. We examined TNF-α, IL-1β, and PIBs, namely C-reactive protein, white blood cell count, neutrophil-to-lymphocyte ratio(NLR), platelet-to-lymphocyte ratio, and systemic immune-inflammation index(SII) according to the presence, location, and score of adhesions determined during secondary laparoscopic procedures.

RESULTS

Only age, postoperative adhesion index(PAI) score, NLR, SII, TNF-α, and IL-1β resulted in a significant difference in the existence of adhesion(P<0.05). The correlation analysis of TNF-α with variables showed that the PAI score and IL 1β levels had a significantly positive correlation.

CONCLUSION

The presence and extent of POA could be predicted by examining the preoperative TNF-α level in patients who had laparoscopic abdominal surgery previously. We could overcome adverse events during secondary laparoscopic procedures by assessing high-risk patients and integrating a personalized surgical approach to managing selected patients.

Progress in diagnosis and treatment of surgery-related adhesive small intestinal obstruction

Adhesive small bowel obstruction is a relatively common surgical acute abdomen, which is caused by various factors that result in the contents of the small bowel failing to pass smoothly. The clinical symptoms include abdominal pain, distension, nausea and vomiting, and defecation disorder. The chance of adhesive small bowel obstruction to develop in patients with a history of abdominal surgery is around 2.4%. This paper discusses the most recent developments in the conservative and surgical management of adhesive small bowel obstruction based on clinical manifestation, laboratory analysis, and imaging examination.

Activating SIRT3 in peritoneal mesothelial cells alleviates postsurgical peritoneal adhesion formation by decreasing oxidative stress and inhibiting the NLRP3 inflammasome

Peritoneal adhesions (PAs) are a serious complication of abdominal surgery and negatively affect the quality of life of millions of people worldwide. However, a clear molecular mechanism and a standard therapeutic strategy for PAs have not been established. Here, we developed a standardized method to mimic the pathological changes in PAs and found that sirtuin 3 (SIRT3) expression was severely decreased in adhesion tissues, which was consistent with our bioinformatics analysis and patient adhesion tissue analysis. Thus, we hypothesized that activating SIRT3 could alleviate postsurgical PAs. Sirt3-deficient (Sirt3^−/−) mice exhibited many more PAs after standardized abdominal surgery. Furthermore, compared with wild-type (Sirt3^+/+) mice, Sirt3-deficient (Sirt3^−/−) mice showed more prominent reactive oxygen species (ROS) accumulation, increased levels of inflammatory factors, and exacerbated mitochondrial damage and fragmentation. In addition, we observed NLRP3 inflammasome activation in the adhesion tissues of Sirt3^−/− but, not Sirt3^+/+ mice. Furthermore, mesothelial cells sorted from Sirt3^−/− mice exhibited impaired mitochondrial bioenergetics and redox homeostasis. Honokiol (HKL), a natural compound found in several species of the genus Magnolia, could activate SIRT3 in vitro. Then, we demonstrated that treatment with HKL could reduce oxidative stress and the levels of inflammatory factors and suppress NLRP3 activation in vivo, reducing the occurrence of postsurgical PAs. In vitro treatment with HKL also restored mitochondrial bioenergetics and promoted mesothelial cell viability under oxidative stress conditions. Taken together, our findings show that the rescue of SIRT3 by HKL may be a new therapeutic strategy to alleviate and block postsurgical PA formation.

Treatment with honokiol, a compound found in magnolia tree bark, significantly reduces formation of internal scar tissue after abdominal surgery in mice. Healing of incisions in the peritoneum, the connective tissue lining the abdomen, can result in scar tissue bonds known as peritoneal adhesions (PA), causing complications such as infertility or bowel obstructions. The mechanism of PA formation is unknown, and no therapies are available. Xuqi Li at The First Affiliated Hospital of Xi’an Jiaotong University, China, and co-workers found that PA tissues in both mice and human patients had decreased levels of SIRT3, a stress-response protein. Mice lacking SIRT3 showed increased inflammation and PA formation. When mice were treated with honokiol the day after surgery in order to boost SIRT3 levels, PA formation was significantly decreased. These results suggest a possible preventative treatment for post-surgical PAs.

Indomethacin Sustained-Release Anti-adhesion Membrane Composed of a Phospholipid and Polycaprolactone Blend

Background

Postoperative peritoneal adhesions are among common challenging problems in surgery. The availability of limited efficient strategies to prevent intra-abdominal adhesion reinforces the need to explore new methods. Given the favorable prolonged drug release characteristics of polycaprolactone (PCL) films and their ability to act as a biodegradable physical barrier implant, along with the anti-inflammatory and anti-adhesion properties of indomethacin and phospholipids, this study hypothesized that indomethacin sustained-release membrane composed of phosphatidylcholine (PC) and PCL blend could efficiently prevent abdominal adhesion formation.

Methods

Different polymeric and polymeric/lipidic hybrid formulations with three feeding materials to drug weight ratios were prepared, and their physicochemical characteristics and drug release kinetics were evaluated and compared. Abdominal adhesions were induced in 48 rats by the abrasion of the cecum and excision of a section of the opposite abdominal wall. Adhesion formation was evaluated by macroscopic scoring, histological, scanning electron microscopy, and polymerase chain reaction analyses.

Results

Both PCL and PCL-PC films exhibited sustained indomethacin release profiles. The X-ray diffraction and Fourier-transform infrared spectroscopy studies confirmed indomethacin incorporation in formulations in molecular dispersion form without any interaction. The films showed smooth surfaces and good mechanical properties. The treatment with indomethacin PCL-PC membrane significantly reduced the expression levels of tumor necrosis factor-alpha, transforming growth factor-beta, interleukin-1, interleukin-6, and fibrinogen in the adhesion tissues. The separation of the injured peritoneum, very low adhesion scores, and complete mesothelial cell regeneration were also achieved.

Conclusions

This study suggests that indomethacin-eluting PCL-PC membrane acting through the combination of physical barrier, anti-inflammatory agents, and controlled drug delivery warrants an effective approach to prevent intra-abdominal adhesion.

Comparison of Oral Sirolimus, Prednisolone, and Combination of Both in Experimentally Induced Peritoneal Adhesion

INTRODUCTION

Peritoneal adhesion formation is a challenging postoperative complication. We aim to evaluate the effect of orally administered sirolimus, prednisolone, and their combination to prevent this entity.

METHODS

Eighty female albino underwent intraperitoneal injection of 3 mL of 10% sterile talc solution to induce peritoneal adhesion, and were subsequently and randomly divided into four groups (each n = 20); including a control group; 1 mg/kg oral prednisolone daily in the morning; 0.1 mg/kg oral sirolimus daily; and a combination group which received both drugs, with the same dosage. On the 29th day, abdominal cavities were explored, and classification was done based on Nair classification.

RESULTS

All rats were healthy on the 29th day, in which exploration was performed. The rats in the control group had extensive intra-abdominal adhesions, while 17 (85%) rats in the control group had substantial adhesion; however, the prednisolone, sirolimus, and combination group had lesser adhesion formation. Also, 14 (70%) rats of prednisolone group, 13 (65%) of sirolimus group, and 16 (80%) of combination group had insubstantial adhesion. The decrease in the grade of peritoneal adhesion bands was highly significant in the combination group (P > 0.001).

CONCLUSIONS

The combination of sirolimus and prednisolone was effective for preventing peritoneal adhesions in rats.

The Inhibitory Effects of Naringin in a Rat Model of Postoperative Intraperitoneal Adhesion Formation

Background

Many attempts have been made to inhibit the formation of postoperative intraperitoneal adhesions, but the results have been discouraging. Therefore, the identification of effective preventative measures or treatments is of great importance. In this study, the substantial potential of naringin (NG) to reduce peritoneal adhesions was validated in a rat model.

Materials and Methods

A rat peritoneal adhesion model was established by abrasion of the cecum and its opposite intraperitoneal region under aseptic surgical conditions. After the operation, three groups of NG-treated rats were given 2 mL of NG by gavage at different concentrations (40, 60, or 80 mg/kg/d). The sham, control, and hyaluronan (HA) groups were given equal volumes of normal saline daily. On the 8th day, all rats were sacrificed 30 min after the administration of an activated carbon solution (10 mL/kg) by oral gavage. Intraperitoneal adhesion formation was adequately evaluated by necropsy, hematoxylin and eosin (HE) staining, Sirius red staining, immunofluorescence staining, enzyme-linked immunosorbent assays, and reactive oxygen species (ROS) probes. The gastrointestinal dynamics of the rats were assessed on the basis of a small intestinal charcoal powder propulsion test and the detection of motilin and gastrin levels in serum.

Results

Intraperitoneal adhesions were markedly reduced in the group of rats receiving high-dose NG. Compared with the control group, the high-dose NG group showed clear reductions in inflammatory reactions, oxidative stress, collagen deposition, and fibroblast formation in the adhesion tissue and enhanced gastrointestinal dynamics (P < 0.05).

Conclusion

NG alleviated the severity of intraperitoneal adhesions in a rat model by reducing inflammation, oxidative stress, collagen deposition, and fibroblast formation, highlighting the potential of NG as a drug candidate to prevent postoperative peritoneal adhesion formation.

Latest Trends on the Attenuation of Systemic Foreign Body Response and Infectious Complications of Synthetic Hernia Meshes

Throughout the past few years, hernia incidence has remained at a high level worldwide, with more than 20 million people requiring hernia surgery each year. Synthetic hernia meshes play an important role, providing a microenvironment that attracts and harbors host cells and acting as a permanent roadmap for intact abdominal wall reconstruction. Nevertheless, it is still inevitable to cause not-so-trivial complications, especially chronic pain and adhesion. In long-term studies, it was found that the complications are mainly caused by excessive fibrosis from the foreign body reaction (FBR) and infection resulting from bacterial colonization. For a thorough understanding of their complex mechanism and providing a richer background for mesh development, herein, we discuss different clinical mesh products and explore the interactions between their structure and complications. We further explored progress in reducing mesh complications to provide varied strategies that are informative and instructive for mesh modification in different research directions. We hope that this work will spur hernia mesh designers to step up their efforts to develop more practical and accessible meshes by improving the physical structure and chemical properties of meshes to combat the increasing risk of adhesions, infections, and inflammatory reactions. We conclude that further work is needed to solve this pressing problem, especially in the analysis and functionalization of mesh materials, provided of course that the initial performance of the mesh is guaranteed.

Curcumin polymeric membranes for postoperative peritoneal adhesion: Comparison of nanofiber vs. film and phospholipid-enriched vs. non-enriched formulations

Intra-abdominal adhesion remains a major postoperative problem and is able to place individuals at lifelong risk of serious complications. Among available approaches, insertion of a barrier membrane at the site of injury partially inhibited adhesion formation. Moreover, the local administration of an anti-adhesive agent showed some favorable effects. In this study, we aimed to prepare and fully characterize polycaprolactone (PCL)-based film casts and electrospun nanofibers (NFs) containing a natural anti-inflammatory agent, curcumin (CUR), with extended-release properties. We also compared their efficiencies in preventing tissue adhesions. Additionally, the impact of soy phosphatidylcholine (SPC) enrichment on adhesion prevention was investigated. Prepared membranes were evaluated in terms of surface morphology (SEM, AFM), surface wettability, CUR release profiles, structural properties (FTIR, XRD, DSC), and mechanical behaviors. To further analyze the anti-adhesion effectiveness, a cecal abrasion model was performed on rats. SEM and AFM images showed a smoother surface in SPC-containing films. Concerning NFs, uniform bead-free fibers were observed and SPC containing NFs showed higher conductivity and lower viscosity and therefore, smaller fibers. All formulations exhibited sustained drug release over 4 weeks. In vivo findings revealed the superior performance of films compared to NFs and phospholipid-enriched formulations over non-enriched ones. Among all film formulations and in comparison to the positive control (Seprafilm®), CUR-SPC-PCL films significantly reduced peritoneal adhesions, as evidenced by gross examination, histological evaluation and immunohistochemical (IHC) analysis. The remarkable in vivo anti-adhesion activity together with suitable in vitro properties have made CUR-SPC-PCL films a promising system for postoperative anti-adhesion purposes in the clinic.

Prevention of Postsurgical Abdominal Adhesion Using Electrospun TPU Nanofibers in Rat Model

Intra-abdominal adhesions following surgery are a challenging problem in surgical practice. This study fabricated different thermoplastic polyurethane (TPU) nanofibers with different average diameters using the electrospinning method. The conditions were evaluated by scanning electron microscopy (SEM), atomic force microscope (AFM), and Fourier transform infrared spectrometer (FTIR) analysis. A static tensile test was applied using a strength testing device to assess the mechanical properties of the electrospun scaffolds. By changing the effective electrospinning parameters, the best quality of nanofibers could be achieved with the lowest bead numbers. The electrospun nanofibers were evaluated in vivo using a rat cecal abrasion model. The macroscopic evaluation and the microscopic study, including the degree of adhesion and inflammation, were investigated after three and five weeks. The resultant electrospun TPU nanofibers had diameters ranging from about 200 to 1000 nm. The diameters and morphology of the nanofibers were significantly affected by the concentration of polymer. Uniform TPU nanofibers without beads could be prepared by electrospinning through reasonable control of the process concentration. These nanofibers' biodegradability and antibacterial properties were investigated by weight loss measurement and microdilution methods, respectively. The purpose of this study was to provide electrospun nanofibers having biodegradability and antibacterial properties that prevent any adhesions or inflammation after pelvic and abdominal surgeries. The in vivo experiments revealed that electrospun TPU nanofibers reduced the degree of abdominal adhesions. The histopathological study confirmed only a small extent of inflammatory cell infiltration in the 8% and 10% TPU. Conclusively, nanofibers containing 8% TPU significantly decreased the incidence and severity of postsurgical adhesions, and it is expected to be used in clinical applications in the future.

PuraStat RADA16 Self-Assembling Peptide Reduces Postoperative Abdominal Adhesion Formation in a Rabbit Cecal Sidewall Injury Model

Objective: To evaluate the effect of PuraStat (2.5% RADA16) administration on postoperative abdominal adhesion formation in an in vivo model.

Methods: Anesthetized New Zealand white rabbits underwent cecal sidewall abrasion surgery in which the cecal serosa and juxtaposed parietal peritoneum were abraded after access through an abdominal midline incision. Eight animals were randomized to receive PuraStat administration at the interface of the injured tissues before incision closure, and five animals served as untreated controls. Treated animals received 3–12 ml PuraStat solution per lesion. Animals were sacrificed 14 days after surgery and examined for adhesion formation at the wound site.

Results: At study terminus, adhesions were identified in 90% (9/10) of abraded cecum/peritoneal wound sites in untreated controls versus 25% (4/16) of PuraStat-treated sites (p = 0.004). Mean ± SD Total Adhesion Score (average of the values for extent + strength of the adhesion in both defects per animal; maximum score = 14 points) was significantly 76% lower in PuraStat-treated animals (2.0 ± 3.0 points) compared to untreated controls (8.2 ± 1.9 points) (p = 0.029). Mean adhesion coverage area of wound sites was 79% lower in PuraStat-treated animals than controls (p < 0.001), and mean adhesion durability was 72% lower in PuraStat-treated animals versus controls (p = 0.005). Remnant hydrogel was observed at the wound sites of 75% of treated animals at postoperative Day 14.

Conclusion: PuraStat treatment has a positive protective effect in the cecal sidewall injury model, and significantly reduces abdominal adhesion formation at the interface of the injured cecum and overlying peritoneal sidewall defect.

Different doses of enoxaparin in the prevention of postoperative abdominal adhesions. Experimental study

Background

Postoperative abdominal adhesions (PAAs) are present in more than 90% of patients undergoing abdominal surgery. They are a cause of chronic pain, hospitalizations, multiple surgeries, and infertility in women of reproductive age. The participation of three processes have been recognized: coagulation, fibrinolysis, and inflammation. The usefulness of subcutaneous enoxaparin in their prevention has been established. The objective is to establish the safest and most efficient dose for PAA prevention by testing five different doses of subcutaneous enoxaparin (0.25, 0.5, 1, 1.5, and 2 mg/kg/day) given in one dose/day for seven days.

Material and methods

Fifty Sprague-Dawley rats were studied, 10 in each group. Adhesions were induced through controlled rubbing of the cecum and suturing of an incision in the terminal ileum. Two independent observers recorded the degree of adhesion formation at 14 days and histologically studied the adhesions.

Statistical analysis

ANOVA compared group averages. The nonparametric Kruskal-Wallis test was used to identify group differences.

Results

The 0.5 mg/kg/day group had greater formation of adhesions (p < 0.001). There was no significant difference between the 1.5 and 2 mg/kg/day groups, though the latter group had an incidence of 27.2% of bleeding in the abdominal cavity. The degree of adhesions in the histological sections coincided with the macroscopic findings. The interobserver agreement was kappa = 0.88 (very good).

Conclusion

The safe and effective dose of subcutaneous enoxaparin to prevent PAA formation was 0.5–1.5 mg/kg/day for seven days.

•

Postoperative abdominal adhesions are the cause of clinical alterations that require significant economic expenses.

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Activation of the coagulation cascade is a component in the formation of adhesions.

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Enoxaparin reduces the appearance of postoperative abdominal adhesions.

•

The prophylactic dose of enoxaparin is sufficient to prevent adhesions.

A functional PVA aerogel-based membrane obtaining sutureability through modified electrospinning technology and achieving promising anti-adhesion effect after cardiac surgery

Pericardial barrier destruction, inflammatory cell infiltration, and fibrous tissue hyperplasia, trigger adhesions after cardiac surgery. There are few anti-adhesion materials that are both functional and sutureable for pericardial reconstruction. Besides, a few studies have reported on the mechanism of preventing pericardial adhesion. Herein, a functional barrier membrane with sutureability was developed via a modified electrospinning method. It was composed of poly(l-lactide-co-caprolactone) (PLCL) nanofibers, poly(vinyl alcohol) (PVA) aerogel, and melatonin, named PPMT. The PPMT had a special microstructure manifested as a staggered arrangement of nanofibers on the surface and a layered macroporous aerogel structure in a cross-section. Besides providing the porosity and hydrophilicity obtained from PVA, the structure also had suitable mechanical properties for stitching due to the addition of PLCL nanofibers. Furthermore, it inhibited the proliferation of fibroblasts by suppressing the activation of Fas and P53, and achieved anti-inflammatory effects by affecting the activity of inflammatory cells and reducing the release of pro-inflammatory factors, such as interleukin 8 (IL-8) and tumor necrosis factor α (TNF-α). Finally, in vivo transplantation showed that it up-regulated the expression of matrix metalloproteinase-1 (MMP1) and tissue inhibitor of metalloproteinase-1 (TIMP1), and down-regulated the expression of Vinculin and transforming growth factor β (TGF-β) in the myocardium, thereby reducing the formation of adhesions. Collectively, these results demonstrate a great potential of PPMT membrane for practical application to anti-adhesion.

•

A functional PVA aerogel-based membrane (PPMT) obtained sutureability through modified electrospinning technology.

•

The primary mechanism to anti-adhesion of PPMT membrane was explored.

•

Promising anti-adhesion effect of PPMT membrane was accomplished in pericardium reconstruction in rabbit.

The effect of N-acetyl-l-cysteine on inflammation after intraperitoneal mesh placement in a potentially contaminated environment: Experimental study in the rat

BACKGROUND

The use of prosthetic meshes in abdominal wall reconstruction is a well-established approach; however, in certain cases where a bowel resection coexists its application is disputed. Any underlying inflammatory process may augment adhesion formation which is a major postoperative complication. In this animal study, our aim was to investigate the effect of N-acetyl-l-cysteine (NAC) on adhesion formation and the expression of inflammatory markers when a mesh was used in a clean or a potentially contaminated environment.

METHODS

Sixty male Wistar rats were randomly and equally allocated in 3 groups: A, B and C. Animals in all groups underwent laparotomy, a prosthetic mesh was placed and chemoprophylaxis with ciprofloxacin was administered. In groups B and C an enterectomy was also performed. NAC was injected intraperitoneally in group C. Adhesion formation, IL-1a, IL-6, TNF-a and histological data including fibrosis, neutrophils' infiltration and neovascularization were assessed. Mesh samples were sent for cultivation.

RESULTS

Adhesion formation was significantly less and inflammation markers were also lower in group C compared to group B (p<0.05). Histological findings were significant for greater fibrosis, neutrophils' infiltration and neovascularization in group B compared to both group A and C. Regarding mesh cultures, more specimens were tested positive in group B (p <0.05). Outcomes between group A and C did not differ.

CONCLUSION

NAC effectively ameliorated adhesion formation and inflammation in a potentially septic environment where a prosthetic mesh was placed.

The prevention of postoperative port-site adhesion following single-port access (SPA) laparoscopic surgeries

ABSTRACT

No studies have examined the issue of intraabdominal port-site adhesion following single-port access (SPA) laparoscopic surgeries. The purpose of the present study was to investigate the clinical effects of temperature-sensitive adhesion barrier solution in preventing periumbilical adhesion in SPA laparoscopy. This was a prospective, single-arm study in which patients were given GUARDIX-SGTM after SPA laparoscopic surgery for benign gynecologic diseases. One gram of GUARDIX-SGTM was applied on the abdominal viscera just below the umbilical port site and adjacent abdominal wall prior to fascia closure. The primary endpoint was the incidence of postoperative adhesion evaluated by visceral sliding technique through transabdominal sonography after three months. Between June 2019 and March 2020, a total of 37 healthy patients without any history of previous abdominal surgery received SPA laparoscopic surgery by a single surgeon. No postoperative complications such as wound dehiscence or surgical site infection occurred during the follow-up period of three months. No postoperative adhesion around the umbilicus was noted in all 37 patients. The mean visceral movement measured by transabdominal sonography during maximal respiration was 4.9 cm (4.9 ± 1.9 cm). Using an adhesion barrier around the port site prior to fascia closure prevents postoperative adhesion in benign SPA laparoscopic gynecologic surgery.

Endostatin in fibrosis and as a potential candidate of anti-fibrotic therapy

Fibrotic diseases pose significant clinical challenges due to their broadness and complexity. Thus, a better understanding of fibrogenesis and the development of more effective treatments is imperative. Recent evidence suggests a significant antifibrotic potential of an endogenous glycoprotein, endostatin. While endostatin has been widely studied for its role as an anticancer adjuvant by inhibiting tumor angiogenesis, its possible implication in fibrosis remains largely unclear. Here, we review the role of endostatin in various cellular processes and highlight its antifibrotic activity. We hypothesize that endostatin conveys a homeostatic function in the process of fibrosis by regulating (a) TGF-β1 and its downstream signaling; (b) RhoA/ROCK pathway; (c) NF-κB signaling pathway; (d) expression of EGR-1; (e) PDGF/PDGFR pathway; (f) autophagy-related pathways; (g) pathways associated with cell proliferation and apoptosis. Finally, we propose a schematic model of the antifibrotic roles and mechanisms of endostatin; also, we outline future research directions of endostatin and aim to present a potential therapeutic approach for fibrosis.

Automatic implantable cardioverter defibrillator (AICD) within the abdomen as a cause of adhesive small bowel obstruction (ASBO): a case report

Adhesive small bowel obstruction (ASBO) is commonly caused by intra-abdominal adhesions, usually from prior surgery. Conservative management is the mainstay of treatment, with adhesiolysis required for non-resolving obstruction. An unusual patient presentation of ASBO is presented here, where the cause is proposed as an automatic implantable cardioverter defibrillator (AICD) within the abdomen. Although the patient had several presentations of ASBO successfully treated with conservative management, a non-resolving obstruction required surgical management. At laparotomy, the AICD was found to be in close association with extensive matted adhesions to adjacent small bowel. Adhesiolysis was performed, with the AICD implanted in a subrectus pocket. The patient had an uncomplicated recovery, and at review 6 weeks following the operation was found to have a normal bowel habit with nil further episodes concerning for obstruction. This case highlights the importance of non-classical risk factors being a possible cause of ASBO.

Establishment of a Rabbit Intervertebral Disc Degeneration Model by Percutaneous Posterolateral Puncturing of Lumbar Discs Under Local Anesthesia

OBJECTIVE

An anterior approach is applied to establish the majority of rabbit intervertebral disc degeneration (IDD) models in current studies. However, for research on disc repair via biomaterial implantation and tissue engineering, this traditional model establishment method has many shortcomings, such as the risk of general anesthesia, unnecessary tissue damage, and the influence of scar formation on the visual field for secondary implantation surgery. The aim of this study was to report a modified method of establishing an IDD model by applying percutaneous posterolateral puncturing for rabbit lumbar disc surgery under local anesthesia.

METHODS

We built a rabbit model of IDD by percutaneous posterolateral annulus fibrosus puncturing (AFP) (with or without nucleus pulposus aspiration [NPA]) under local anesthesia. Then, we analyzed the outcome after 12 weeks via magnetic resonance images, disc height changes, and disc histologic grades determined from morphologic observation and histologic analyses (hematoxylin and eosin and safranin-O staining and type II collagen expression analysis).

RESULTS

The IDD model was successfully built based on both AFP and AFP/NPA, as demonstrated by the results of magnetic resonance imaging index, morphologic, and histologic analyses. Both methods can successfully produce an IDD model after 12 weeks. However, we found that the addition of NPA significantly enhanced the modeling results.

CONCLUSIONS

Our results show that percutaneous posterolateral AFP/NPA of rabbit lumbar discs under local anesthesia is a minimally invasive, safe and reproducible method of establishing an IDD model. The posterolateral surgical approach is especially suitable for disc regeneration studies that require secondary biomaterial implantation via an anterior approach after the IDD model is established.

Accuracy of third trimester ultrasound in predicting neonatal birthweight in patients with inflammatory bowel disease

OBJECTIVE

To evaluate the accuracy of third trimester ultrasound in predicting birthweight in patients with inflammatory bowel disease (IBD) using the gestation-adjusted projection (GAP) method.

STUDY DESIGN

Retrospective cohort study including pregnant patients with IBD who had third trimester ultrasounds and delivered at a single institution from 2012 to 2017. Controls included pregnant patients without IBD seen during the study period with third trimester ultrasounds. Correlation plots of GAP birthweight and actual birthweight (AB) were created for IBD-positive cases, IBD-negative controls, and IBD-positive cases with and without prior abdominal surgery. GAP predicted birthweight error was calculated for cases and controls. Univariable linear regression models estimated the association between predicted birthweight and AB. Multivariable linear regression models estimated the association between GAP birthweight and AB adjusting for age, BMI, race, and IBD status.

RESULTS

320 patients were included (172 cases and 148 controls). Cases were more likely to be older (p < 0.001), white (p < 0.001), and have a lower BMI (p = 0.001). Correlation plots of GAP birthweight and AB showed linear correlations in cases (Spearman ρ = 0.81), controls (ρ = 0.74), cases with (p = 0.78) and without prior surgery (ρ = 0.83). GAP birthweight was significantly associated with AB in controls and cases in univariable linear regression models (β = 0.85, standard error = 0.04, p < 0.001; β = 0.90, standard error = 0.06, p < 0.001, respectively). No significant difference was found between the parameter estimates of the two models (p = 0.47). GAP birthweight remained significantly associated with AB in a multivariable linear regression model (β = 0.86, standard error = 0.03, p < 0.001). There were no significant differences between GAP predicted birthweight error between controls and cases (APE 11% vs 10% respectively, p = 0.56) and between cases without and with prior surgery (APE 10% vs 11%, p = 0.7).

CONCLUSION

The accuracy of fetal biometry in the third trimester for predicting actual birthweight was equivalent between patients with and without IBD and those with prior abdominal surgery.

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.