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

Preventive Effects of Bioabsorbable Anti-Adhesion Barriers on Bowel Obstruction After Colectomy in Colon Cancer Patients: A Retrospective Cohort Study Using an Insurance Claims Database

PURPOSE

Postoperative adhesions can be prevented by the use of bioabsorbable anti-adhesion barriers. Although the occurrence of postoperative bowel obstruction is an important concern for patients, at the time of approval of anti-adhesion barriers, its effectiveness in preventing postoperative bowel obstruction had not been evaluated. We aimed to retrospectively evaluate the incidence of bowel obstruction after colectomy in patients with colon cancer using an insurance claims database.

METHODS

This retrospective cohort study analyzed the data of colon cancer patients (between 2005 and 2017 from a national insurance claims database) who underwent colectomies to compare the proportion of individuals with postoperative bowel obstruction between the barrier and no barrier groups.

RESULTS

Of the 587 patients who met the inclusion criteria, 308 and 279 patients were identified as the barrier and no barrier groups, respectively. The incidence of postoperative bowel obstruction was significantly lower in the barrier group (log-rank test, P = 0.0483). The cumulative incidence of postoperative bowel obstruction 37 months after the initial colectomy was 6.1% and 10.9% in the barrier and no barrier groups, respectively. Moreover, consistent results were obtained in the matched cohort.

CONCLUSION

In colectomies for patients with colon cancer, the use of anti-adhesion barriers could significantly reduce the incidence of postoperative bowel obstruction. Evaluations using insurance claims databases could provide important information on outcomes following implementation of medical devices.

A ROS-responsive and scavenging hydrogel for postoperative abdominal adhesion prevention

Postoperative abdominal adhesion (PAA) widely occurs after abdominal surgery, which often produces severe complications. However, there were still no satisfactory anti-adhesive products including barriers and anti-adhesive agents. Herein, we developed a ROS-responsive and scavenging hydrogel barrier, termed AHBC/PSC, wherein the monomer AHBC was synthesized by phenylboronic acid (PBA)-modified hyaluronic acid (HA-PBA) further grafted with adipic dihydrazide (ADH) and PBA-based chlorogenic acid (CGA) via ROS-sensitive borate ester bond, and the other monomer PSC was constructed by polyvinyl alcohol (PVA) grafted with sulfated betaine (SB) and p-hydroxybenzaldehyde (CHO). Further, the double crosslinked AHBC/PSC hydrogel was successfully fabricated between AHBC and PSC via forming dynamic covalent acylhydrazone bonds and borate ester bonds. Results showed that AHBC/PSC hydrogel had in situ gelation behavior, satisfactory mechanical properties (storage modulus of about 1 kPa and loss factor Tan δ of about 0.5), suitable wet tissue adhesion strength of about 2.3 kPa on rat abdominal wall, and good biocompatibility, achieving an ideal physical barrier. Particularly, CGA could be responsively released from the hydrogel by breakage of borate ester bonds between CGA and PBA based on high reactive oxygen species (ROS) levels of damaged tissue and exhibited great ROS scavenging capability to regulate inflammation and promote the polarization of macrophages from pro-inflammatory M1 phenotype to anti-inflammatory M2 phenotype. Moreover, the grafted SB as a zwitterionic group could reduce protein adsorption and fibroblast adhesion. Finally, the in vivo experiments revealed that AHBC/PSC hydrogel with good safety and in vivo retention behavior of about 2 weeks, effectively prevented PAA by regulating the inflammatory microenvironment and alleviating the fibrosis process. In brief, the versatile AHBC/PSC hydrogel would provide a more convenient and efficient approach for PAA prevention. STATEMENT OF SIGNIFICANCE: Postoperative abdominal adhesion (PAA) widely occurs after surgery and is often accompanied by severe complications. Excessive inflammation and oxidative stress are very crucial for PAA formation. This study provides a ROS-responsive and scavenging hydrogel with suitable mechanical properties, good biocompatibility and biodegradability, and resistance to protein and fibroblast. The antioxidant and anti-inflammatory active ingredient could be responsively released from the hydrogel via triggering by the high ROS levels in the postoperative microenvironment thereby regulating the inflammatory balance. Finally, the hydrogel would effectively regulate the development process of PAA thereby achieving non-adhesion wound healing.

Neutrophil Extracellular Traps-Inhibiting and Fouling-Resistant Polysulfoxides Potently Prevent Postoperative Adhesion, Tumor Recurrence, and Metastasis

Peritoneal metastasis (PM) is considered one of the most dreaded forms of cancer metastases for both patients and physicians. Aggressive cytoreductive surgery (CRS) is the primary treatment for peritoneal metastasis. Unfortunately, this intensive treatment frequently causes clinical complications, such as postoperative recurrence, metastasis, and adhesion formation. Emerging evidence suggests that neutrophil extracellular traps (NETs) released by inflammatory neutrophils contribute to these complications. Effective NET-targeting strategies thus show considerable potential in counteracting these complications but remain challenging. Here, one type of sulfoxide-containing homopolymer, PMeSEA, with potent fouling-resistant and NET-inhibiting capabilities, is synthesized and screened. Hydrating sulfoxide groups endow PMeSEA with superior nonfouling ability, significantly inhibiting protein/cell adhesion. Besides, the polysulfoxides can be selectively oxidized by ClO- which is required to stabilize the NETs rather than H2O2, and ClO- scavenging effectively inhibits NETs formation without disturbing redox homeostasis in tumor cells and quiescent neutrophils. As a result, PMeSEA potently prevents postoperative adhesions, significantly suppresses peritoneal metastasis, and shows synergetic antitumor activity with chemotherapeutic 5-Fluorouracil. Moreover, coupling CRS with PMeSEA potently inhibits CRS-induced tumor metastatic relapse and postoperative adhesions. Notably, PMeSEA exhibits low in vivo acute and subacute toxicities, implying significant potential for clinical postoperative adjuvant treatment.

Nonswellable Hydrogel Patch with Tissue-Mimetic Mechanical Characteristics Remodeling In Vivo Microenvironment for Effective Adhesion Prevention

Postoperative adhesion is a common complication after abdominal surgery, but current clinical products have unsatisfactory therapeutic effects. Here, we present a hydrogel patch formed in a single step through dialysis. The exchange of DMSO into water facilitates hydrophobic aggregate in situ formation and the formation of hydrogen bonds within the hydrogel. Thanks to the optimized component ratio and precise structural design. The hydrogel patch has soft-tissue-like mechanical characteristics, including high strength, high toughness, low modulus similar to the abdominal wall, good fatigue resistance, and fast self-recovery properties. The nonswellable hydrogel patch retains over 80% of its original mechanical properties after 7 days of immersion in physiological saline, with a maximum swelling ratio of 5.6%. Moreover, the hydrophobic biomultifunctionality of benzyl isothiocyanate can self-assemble onto the hydrogel patch during the sol-gel transition process, enabling it to remodel the inflammatory microenvironment through synergistic antibacterial, antioxidant, and anti-inflammatory effects. The hydrogel patch prevents postsurgical adhesion in a rat sidewall defect-cecum abrasion model and outperforms the leading commercial Interceed. It holds promising potential for clinical translation, considering that FDA-approved raw materials (PVA and gelatin) form the backbone of this effective hydrogel patch.

CuSO4/H2O2induced polydopamine/polysulfobetaine methacrylate co-deposition on poly(amino acid) membranes for improved anti-protein adsorption and antibacterial activity

Stopping postoperative soft tissue adhesions is one of the most challenging clinical problems that needs to be addressed urgently to avoid secondary injury and pain to patients. Currently, membrane materials with anti-protein adsorption and antibacterial activity are recognized as an effective and promising anti-adhesion barrier to prevent postoperative adhesion and the recurrent adhesion after adhesiolysis. Herein, poly(amino acid) (PAA), which is structurally similar to collagen, is selected as the membrane base material to successfully synthesize PAA-5 membranes with excellent mechanical and degradation properties by in-situ melt polymerization and hot-melt film-forming technology. Subsequently, the co-deposition of polydopamine/polysulfobetaine methacrylate (PDA/PSBMA) coatings induced by CuSO4/H2O2on PAA-5 membranes results in the formation of PDC-5S and PDC-10S, which exhibit excellent hemocompatibility, protein antifouling properties, and cytocompatibility. Additionally, PDC-5S and PDC-10S demonstrated significant antibacterial activity againstEscherichia coliandStaphylococcus aureus, with an inhibition rate of more than 90%. As a result, this study sheds light on newly discovered PAA membranes with anti-protein adsorption and antibacterial activity can sever as one of the promising candidates for the prevention of postoperative peritoneum adhesions.

Hybrid Bioactive Hydrogel Promotes Liver Regeneration through the Activation of Kupffer Cells and ECM Remodeling After Partial Hepatectomy

Partial hepatectomy is an essential surgical technique used to treat advanced liver diseases such as liver tumors, as well as for performing liver transplants from living donors. However, postoperative complications such as bleeding, abdominal adhesions, wound infections, and inadequate liver regeneration pose significant challenges and increase morbidity and mortality rates. A self-repairing mixed hydrogel (O5H2/Cu2+/SCCK), containing stem cell derived cytokine (SCCK) derived from human umbilical cord mesenchymal stem cells (HUMSCs) treated with the traditional Chinese remedy Tanshinone IIA (TSA), is developed. This SCCK, in conjunction with O5H2, demonstrates remarkable effects on Kupffer cell activation and extracellular matrix (ECM) remodeling. This leads to the secretion of critical growth factors promoting enhanced proliferation of hepatocytes and endothelial cells, thereby facilitating liver regeneration and repair after partial hepatectomy. Furthermore, the hydrogel, featuring macrophage-regulating properties, effectively mitigates inflammation and oxidative stress damage in the incision area, creating an optimal environment for postoperative liver regeneration. The injectability and strong adhesion of the hydrogel enables rapid hemostasis at the incision site, while its physical barrier function prevents postoperative abdominal adhesions. Furthermore, the hydrogel's incorporation of Cu2+ provides comprehensive antibacterial effects, protecting against a wide range of bacteria types and reducing the chances of infections after surgery.

Evaluation of 4DryField® as an Adhesion Prophylaxis in Pediatric Patients: A Propensity-Score Matched Study

INTRODUCTION

 Abdominal adhesions following surgery can lead to complications like intestinal obstruction and pelvic pain. While no molecular therapies currently target the underlying adhesion formation process, various barrier agents exist. 4DryField® has shown promise in reducing bleeding and adhesions in adults. This study aimed to assess its effectiveness in children.

METHODS

 The study examined all pediatric patients who underwent laparotomy between January 2018 and February 2022. It compared outcomes between those treated with 4DryField® and a control group. Key endpoints included surgical revision, adhesion recurrence, infections, insufficiencies, fever, C-reactive protein (CRP) levels, and time to gastrointestinal passage.

RESULTS

 In total, 233 children had surgery for bowel adhesions. After propensity score matching, 82 patients were included in the analysis: 39 in the control and 43 in the 4DryField® group. 4DryField® did not affect the readhesion rate. Children in the treatment group had significantly more complications (47 vs. 15%, p = 0.002), more often fever, and higher CRP levels.

CONCLUSIONS

 4DryField® did not show potential in reducing adhesion formation, but it was associated with significantly more complications in pediatric patients. Thus, future prospective studies are needed to evaluate the safety and effectiveness of 4DryField® in children.

Intra-peritoneal lavage of Zingiber officinale rhizome and its active constituent gingerol impede inflammation, angiogenesis, and fibrosis following post-operative peritoneal adhesion in male rats

Post-operative peritoneal adhesions (PA) are a common and important clinical problem. In this study, we focused on the ameliorative efficacy of ginger and gingerol compounds on surgical-induced peritoneal adhesion, and their strategies that disrupted the PA formation pathways to suppress their incidence. First, liquid chromatography-mass spectrometry (LC-MS) was established to separate and identify several chemical groups of ginger rhizome extract. In the next steps, male Wistar albino rats were randomly selected and divided into various groups, namely sham, control, ginger extract (0.6, 1.8, 5 %w/v), and gingerol (0.05, 0.1, 0.3, and 1 %w/v). Finally, we investigated the macroscopic parameters such as wound healing, body weight as well as spleen height and weight. In addition, visual peritoneal adhesion assessment was performed via Nair et al and Adhesion Scoring Scheme. Moreover, the microscopic parameters and biological assessment was performed via and immunoassays. The present findings revealed significant improvement in wound healing and reduction of the adhesion range, as Nair et al. and Adhesion Scoring Scheme scoring, in both the ginger and gingerol groups compared to the PA group (P < 0.05). Whereas, gingerol (0.3 % w/v) was able to increase the body weight in rats (P < 0.0001) at end stage of experiment. Also, inflammation, angiogenesis, and fibrosis were significantly decreased due to the downregulation of interleukin (IL)-6, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, vascular endothelial growth factor (VEGF), respectively, in the ginger and gingerol groups compared to the PA group (P < 0.05). In contrast, the levels of IL-10 were increased in the ginger and gingerol groups compared to the control group (P < 0.01). Our results proved that ginger rhizome and gingerol, as novel therapeutic compounds, could be used to prevent PA for their beneficial anti-inflammatory as well as anti-fibrosis properties in clinical trials. However, further clinical studies are required to approve the effectiveness of ginger and gingerol.

A Graphene Composite Film Based Wearable Far-Infrared Therapy Apparatus (GRAFT) for Effective Prevention of Postoperative Peritoneal Adhesion

Postoperative peritoneal adhesion (PPA) is the most frequent complication after abdominal surgery. Current anti-adhesion strategies largely rely on the use of physical separating barriers creating an interface blocking peritoneal adhesion, which cannot reduce inflammation and suffers from limited anti-adhesion efficacy with unwanted side effects. Here, by exploiting the alternative activated macrophages to alleviate inflammation in adhesion development, a flexible graphene-composite-film (F-GCF) generating far-infrared (FIR) irradiation that effectively modulates the macrophage phenotype toward the anti-inflammatory M2 type, resulting in reduced PPA formation, is designed. The anti-adhesion effect of the FIR generated by F-GCF is determined in the rat abdominal wall abrasion-cecum defect models, which exhibit reduced incidence and area of PPA by 67.0% and 92.1% after FIR treatment without skin damage, significantly superior to the clinically used chitosan hydrogel. Notably, within peritoneal macrophages, FIR reduces inflammation reaction and promotes tissue plasminogen activator (t-PA) level via the polarization of peritoneal macrophages through upregulating Nr4a2 expression. To facilitate clinical use, a wirelessly controlled, wearable, F-GCF-based FIR therapy apparatus (GRAFT) is further developed and its remarkable anti-adhesion ability in the porcine PPA model is revealed. Collectively, the physical, biochemical, and in vivo preclinical data provide compelling evidence demonstrating the clinical-translational value of FIR in PPA prevention.

What Should I Use? Impact of Adhesion Barriers on Postoperative Abdominal Complications: A Systematic Review

BACKGROUND

Adhesions are a feared complication of abdominal surgery. There have been many new adhesion barriers developed and tested; however, there is no recent systematic review analyzing all the published literature. To address this, we aimed to analyze the different types of adhesion barriers, and determine their effects on postoperative outcomes in patients.

METHODS

A total of 14,038 articles utilizing adhesion barriers in abdominal surgery were retrieved from the PubMed, EMBASE, and Scopus databases. Inclusion criteria were: patients undergoing abdominal surgery, patients receiving an adhesion barrier, and reported postoperative outcomes. Two reviewers independently screened titles/abstracts and full-text articles using Covidence. The ROBINS-I tool was used to assess the quality of the included studies. Study protocol: Prospero CRD42023458230.

RESULTS

A total of 20 studies, with no overall high risk of bias, with 171,792 patients were included. Most studies showed an equivocal benefit for adhesion barriers, with no singular adhesion barrier type that had definitive superior outcomes compared to the others. Bioresorbable barriers emerged as the most extensively researched adhesion barrier type, exhibiting promising results in colorectal surgery. Starch-based adhesion barriers also exhibited a reduction in overall postoperative bowel obstructions and may be beneficial for stoma sites and port closures. On the other hand, many studies raised concerns regarding complications, including risk of abscess formation, fistula development, peritonitis, and anastomotic leakage.

CONCLUSIONS

Adhesion barriers should be considered on a case-by-case basis, however, they should not be utilized prophylactically in all abdominal surgeries due to their risk of complications.

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.

Laparoscopic application of sodium hyaluronate-carboxymethylcellulose barrier in abdominopelvic surgery: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Systematic Review Protocols-compliant systematic review and meta-analysis

BACKGROUND

We aimed to evaluate the incidence of postoperative adhesion formation and adhesion-related consequences (eg, bowel obstruction) after placement of a sodium hyaluronate-carboxymethylcellulose adhesion barrier after laparoscopic abdominopelvic surgery.

METHODS

In this systematic review and meta-analysis, we searched the Medical Literature Analysis and Retrieval System Online and Embase via Ovid, Cochrane Central Register of Controlled Trials, ScienceDirect, BIOSIS Previews, Cumulative Index to Nursing and Allied Health Literature, and Clinical Trial Registries. A manual search (eg, Google Scholar and professional association websites) was also conducted to supplement the electronic database results. Two reviewers independently identified relevant studies based on inclusion and exclusion criteria and extracted data.

RESULTS

A total of 28 studies were included in the systematic qualitative review. Three of the 28 studies included had comparable outcome measures, interventions, and control groups, allowing the pooling of study data. A total of 938 patients (490 patients in the sodium hyaluronate-carboxymethylcellulose barrier group and 448 in the no adhesion barrier group) from these 3 studies were included in the meta-analyses, which found the incidence of bowel obstruction was significantly lower (65% risk reduction) in the sodium hyaluronate-carboxymethylcellulose barrier group compared with the control group (relative risk = 0.35; 95% confidence interval, 0.19-0.63; P = .005) with extremely low heterogeneity between studies (I2 = 0; P = .41). The placement of sodium hyaluronate-carboxymethylcellulose barrier laparoscopically did not create new safety signals nor did it increase the incidence of adverse events.

CONCLUSION

Our meta-analysis found that laparoscopic application of a sodium hyaluronate-carboxymethylcellulose barrier in abdominopelvic surgery reduces the risk of bowel obstruction where applied during the early postoperative phase.

Spray-Type Adhesion Barrier Enhances Safety and Feasibility of Robotic Repeat Liver Resection: Initial Experience and Outcomes

Background Although various types of adhesion barriers are widely utilized in liver surgery, the safety and feasibility of their use during repeat robotic liver resection (R-RLR) are still unknown. Methods Among the 68 patients undergoing RLR with the application of the spray-type adhesion barrier at Kokura Memorial Hospital, Kitakyushu, Japan, between 2021 and 2023, 24 cases that underwent R-RLR were included in this study. The included patients were divided into two groups: those who underwent previous hepatectomy with the use of a spray-type adhesion barrier (R-RLR-B, n = 14) and those without its previous use (R-RLR-NB, n = 10). The perioperative outcomes were compared between the groups. Results There were no differences between the R-RLR-B and R-RLR-NB groups in background characteristics, difficulty scores, operative and console time, or surgical blood loss. Although no difference was found between the groups in the time required for adhesiolysis before the robotic operation, both the time required for robotic adhesiolysis (75 minutes vs. 58 minutes, p = 0.034) and total time for adhesiolysis (192 minutes vs. 141 minutes, p = 0.014) were significantly shorter in the R-RLR-B group than in the R-RLR-NB group. Otherwise, there was no conversion to open hepatectomy, no intraoperative transfusion of red blood cells, no cases of grade B or C post-hepatectomy liver failure, and no mortality in the whole cohort. Conclusions The spray-type adhesion barrier may not be associated with an increase in the incidence of postoperative complications, including bile leakage or intraperitoneal abscess. In addition, its application during the previous hepatectomy can facilitate a secure R-RLR with reduced time for adhesiolysis. Thus, the use of the spray-type adhesion barrier for R-RLR is safe, effective, and time efficient.

Changing patterns and surgical outcomes of small bowel obstruction in the era of minimally invasive surgery for colorectal cancer

INTRODUCTION

This study aimed to investigate whether the incidence, patterns, and surgical outcomes of small bowel obstruction (SBO) have changed in the era of minimally invasive surgery (MIS) for primary colorectal cancer (CRC).

METHODS

Consecutive patients who underwent laparotomy for SBO were divided into MIS and traditional open surgery (TOS) groups based on the previous colorectal cancer operation technique used. The MIS group was selected from 1544 consecutive patients who underwent MIS as a treatment for primary CRCs between 2014 and 2022, while the TOS group was selected from 1604 consecutive patients who underwent TOS as a treatment for primary CRCs between 2004 and 2013. The demographics, clinicopathological features, and surgical outcomes were compared between the two groups.

RESULTS

The SBO incidence in patients who underwent MIS for primary CRC was significantly lower than that in patients who underwent TOS (4.4%, n =68/1544 vs. 9.7%, n =156/1604, P <0.0001). Compared with the TOS group, the MIS group had significantly different ( P <0.0001) SBO patterns: adhesion (48.5 vs. 91.7%), internal herniation (23.5 vs. 2.6%), external herniation (11.8 vs. 1.9%), twisted bowel limbs (4.4 vs. 0.6%), ileal volvulus with pelvic floor adhesion (5.9 vs. 1.9%), and nonspecific external compression (5.9 vs. 1.3%). A subset analysis of patients with adhesive SBO (ASBO) showed that the MIS group tended to ( P <0.0001) have bands or simple adhesions (75.8%), whereas the TOS group predominantly had matted-type adhesions (59.4%). Furthermore, SBO in the MIS group had an acute (<3 months) or early (3-12 months) onset (64.7%), while that in the TOS group ( P <0.0001) had an intermediate or a late onset. When the surgical outcomes of SBO were evaluated, the TOS group had significantly more ( P <0.0001) blood loss and longer operation time; however, no significant difference was observed in the surgical morbidity/mortality (Clavien-Dindo classification ≧3, 11.8 vs. 14.1%, P =0.6367), hospitalization, and readmission rates between the two groups. Postoperative follow-up showed that the estimated 3-year (11.37 vs. 18.8%) and 6-year (25.54 vs. 67.4%) recurrence rates of SBO were significantly lower ( P =0.016) in the MIS group than in the TOS group.

CONCLUSIONS

The wide adoption of MIS to treat primary CRC has led to a lower incidence, altered patterns, and reduced recurrence rates of SBO. Awareness of this new trend will help develop surgical techniques to prevent incomplete restoration of anatomical defects and bowel malalignments specifically associated with MIS for CRC, as well as facilitate timely and appropriate management of SBO complications whenever they occur.

What is the impact of intraperitoneal surfactant administration against postoperative intraabdominal adhesion formation? an experimental study

Background/Aim

Surfactant is a surface-active substance that, in addition to its detergent effect, also has effects that reduce inflammation and fibrosis. Because of these effects, it was aimed herein to investigate the effect of intraperitoneal surfactant application on preventing postoperative peritoneal adhesion formation in a uterine horn adhesion model.

Materials and methods

Twenty-one Wistar albino rats were randomly divided into 3 groups (G1-G3), as follows: G1 (n = 7): control group. The abdomen was opened and then closed; G2 (n = 7): adhesion group. The abdomen was opened. Then, a 2-cm linear incision was made over the right uterine horn, 2 mL of isotonic saline was administered intraperitoneally, and the abdomen was closed; and G3 (n = 7): treatment group. The abdomen was opened, a 2-cm linear incision was made over the right uterine horn, 2 mL (70 mg/kg) of surfactant was administered intraperitoneally, and the abdomen was closed. After 15 days, the rats were euthanized, the abdomens were reopened, and adhesion scoring was performed. After the right uterine horns were removed and fixed with 10% formalin, appropriate sections were taken from the traumatized tissue, stained with Masson's trichrome, and fibrosis and inflammation scoring were performed.

Results

The adhesion area and intensity were significantly higher in G2 than in G1 and G3 (p = 0.001) and were similar in G1 and G3 (p = 0.165). While fibrosis and inflammation were significantly higher in G2 than in G1 and G3 (p = 0.001), there was no difference between G1 and G3 (p = 0.5).

Conclusion

Intraperitoneal surfactant administration at a dose of 70 mg/kg was found to be effective in preventing intraabdominal adhesion formation in a rat uterine horn model.

Multifunctional calcium polyphenol networks reverse the hostile microenvironment of trauma for preventing postoperative peritoneal adhesions

Abdominal adhesions, a commonly observed complication of abdominal surgery, have a high incidence and adversely affect patients' physical and mental health. The primary causes of abdominal adhesions are intraoperative trauma, acute inflammatory response, bleeding, and foreign body infection. Because most current treatment approaches for abdominal adhesions are limited, improved and novel postoperative anti-adhesion regimens are urgently needed. In this study, we developed calcium polyphenol network (CaPN) microspheres based on the self-assembly of the natural triphenolic compound gallic acid and Ca2+ in solution. The physicochemical properties of CaPNs, including their hemostatic, antibacterial, antioxidant, and anti-inflammatory activities, were investigated in vitro. Bleeding and cecal-abdominal wall adhesion models were established to observe the hemostatic activity of CaPNs and their preventive effect on postoperative abdominal wall adhesion in vivo. The results showed that CaPNs significantly reduced inflammation, oxidative stress, fibrosis, and abdominal adhesion formation and had good hemostatic and antibacterial properties. Our findings suggest a novel strategy for the prevention of postoperative adhesions.

Prevention strategies of postoperative adhesion in soft tissues by applying biomaterials: Based on the mechanisms of occurrence and development of adhesions

Postoperative adhesion (POA) widely occurs in soft tissues and usually leads to chronic pain, dysfunction of adjacent organs and some acute complications, seriously reducing patients' quality of life and even being life-threatening. Except for adhesiolysis, there are few effective methods to release existing adhesion. However, it requires a second operation and inpatient care and usually triggers recurrent adhesion in a great incidence. Hence, preventing POA formation has been regarded as the most effective clinical strategy. Biomaterials have attracted great attention in preventing POA because they can act as both barriers and drug carriers. Nevertheless, even though much reported research has been demonstrated their efficacy on POA inhibition to a certain extent, thoroughly preventing POA formation is still challenging. Meanwhile, most biomaterials for POA prevention were designed based on limited experiences, not a solid theoretical basis, showing blindness. Hence, we aimed to provide guidance for designing anti-adhesion materials applied in different soft tissues based on the mechanisms of POA occurrence and development. We first classified the postoperative adhesions into four categories according to the different components of diverse adhesion tissues, and named them as "membranous adhesion", "vascular adhesion", "adhesive adhesion" and "scarred adhesion", respectively. Then, the process of the occurrence and development of POA were analyzed, and the main influencing factors in different stages were clarified. Further, we proposed seven strategies for POA prevention by using biomaterials according to these influencing factors. Meanwhile, the relevant practices were summarized according to the corresponding strategies and the future perspectives were analyzed.

Predicting long-term risk of reoperations following abdominal and pelvic surgery: a nationwide retrospective cohort study

BACKGROUND

The risk of reoperations after abdominal and pelvic surgery is multifactorial and difficult to predict. The risk of reoperation is frequently underestimated by surgeons as most reoperations are not related to the initial procedure and diagnosis. During reoperation, adhesiolysis is often required, and patients have an increased risk of complications. Therefore, the aim of this study was to provide an evidence-based prediction model based on the risk of reoperation.

MATERIALS AND METHODS

A nationwide cohort study was conducted including all patients undergoing an initial abdominal or pelvic operation between 1 June 2009 and 30 June 2011 in Scotland. Nomograms based on multivariable prediction models were constructed for the 2-year and 5-year overall risk of reoperation and risk of reoperation in the same surgical area. Internal cross-validation was applied to evaluate reliability.

RESULTS

Of the 72 270 patients with an initial abdominal or pelvic surgery, 10 467 (14.5%) underwent reoperation within 5 years postoperatively. Mesh placement, colorectal surgery, diagnosis of inflammatory bowel disease, previous radiotherapy, younger age, open surgical approach, malignancy, and female sex increased the risk of reoperation in all the prediction models. Intra-abdominal infection was also a risk factor for the risk of reoperation overall. The accuracy of the prediction model of risk of reoperation overall and risk for the same area was good for both parameters ( c -statistic=0.72 and 0.72).

CONCLUSIONS

Risk factors for abdominal reoperation were identified and prediction models displayed as nomograms were constructed to predict the risk of reoperation in the individual patient. The prediction models were robust in internal cross-validation.

A feasible and safe approach for repeat laparoscopic liver resection and patient selection based on standardized preoperative prediction of surgical difficulty

PURPOSE

This study was performed to propose a strategy for repeat laparoscopic liver resection (RLLR) and investigate the preoperative predictive factors for RLLR difficulty.

METHODS

Data from 43 patients who underwent RLLR using various techniques at 2 participating hospitals from April 2020 to March 2022 were retrospectively reviewed. Surgical outcomes, short-term outcomes, and feasibility and safety of the proposed techniques were evaluated. The relationship between potential predictive factors for difficult RLLR and perioperative outcomes was evaluated. Difficulties associated with RLLR were analyzed separately in two surgical phases: the Pringle maneuver phase and the liver parenchymal transection phase.

RESULTS

The open conversion rate was 7%. The median surgical time and intraoperative blood loss were 235 min and 200 mL, respectively. The Pringle maneuver was successfully performed in 81% of patients using the laparoscopic Satinsky vascular clamp (LSVC). Clavien-Dindo class ≥III postoperative complications were observed in 12% of patients without mortality. An analysis of the risk factors for predicting difficult RLLR showed that a history of open liver resection was an independent risk factor for difficulty in the Pringle maneuver phase.

CONCLUSION

We present a feasible and safe approach to address RLLR difficulty, especially difficulty with the Pringle maneuver using an LSVC, which is extremely useful in RLLR. The Pringle maneuver is more challenging in patients with a history of open liver resection.

Biocompatible and biodegradable chitin-based hydrogels crosslinked by BDDE with excellent mechanical properties for effective prevention of postoperative peritoneal adhesion

Postoperative peritoneal adhesions are common complications caused by abdominal and pelvic surgery, which seriously impact the quality of life of patients and impose additional financial burdens. Using of biomedical materials as physical barriers to completely isolate the traumatic organ and injured tissue is an optimal strategy for preventing postoperative adhesions. However, the limited efficacy and difficulties in the complete degradation or integration of biomedical materials with living tissues restrict the application of these materials. In this study, novel chitin-based crosslinked hydrogels with appropriate mechanical properties and flexibilities were developed using a facile and green strategy. The developed hydrogels simultaneously exhibited excellent biocompatibilities and resistance to nonspecific protein adsorption and NIH/3T3 fibroblast adhesion. Furthermore, these hydrogels were biodegradable and could be completely integrated into the native extracellular matrix. The chitin-based crosslinked hydrogels also effectively inhibited postoperative peritoneal adhesions in rat models of adhesion and recurrence. Therefore, these novel chitin-based crosslinked hydrogels are excellent candidate physical barriers for the efficient prevention of postoperative peritoneal adhesions and provide a new anti-adhesion strategy for biomedical applications.

Clinical feasibility of absorbable gelatin film adhesion barrier (GM142 "TENALEAF®") in gynecological laparoscopic surgery: Safety assessment for first-in-human use and surgical video

AIM

To evaluate the safety and operability of the GM142 (TENALEAF®, Medical Division, Gunze Limited, Tokyo, Japan) adhesion barrier applied in patients undergoing surgery for benign gynecologic disease.

METHODS

This multicenter open study enrolled 34 patients from November 2018 to October 2019.

RESULTS

The primary outcome was the incidence of adverse events (AE) within 12 weeks postoperatively. None of the 30 patients completing the study experienced a life-threatening AE. Thirteen patients (43.3%) suffered 30 mild or moderate AE in total. No intestinal obstruction (0/30) was observed, with the sample size justified by the AdSpray® trial (8/61 patients with AE). No gelatin-specific Immunoglobulin E (IgE) antibodies were induced in the patients. The adhesion barrier could be easily inserted (even via trocar) and positioned. After malfunctions were reported in six patients, the instructions for use were updated for trocar use.

CONCLUSION

This study showed the safety and clinical feasibility GM142 as an adhesion barrier.

Light-Activated Chemically Reactive Fibrous Patch Revolutionizes Wound Repair Through the Prevention of Postoperative Adhesion

A light-activated chemically reactive fibrous patch (ChemPatch) with tissue adhesion and wound healing activity was developed for preventing postoperative peritoneal adhesion. ChemPatch was constructed by an integrative electrospinning fabrication strategy, generating multifunctional PCL-NHS fibers encapsulating antioxidant curcumin and MnO₂ nanoparticles. ChemPatch exhibited excellent photothermal conversion, which not only reformed the physical state to match the tissue but also improved conjugation between ChemPatch and tissues, allowing for strong attachment. Importantly, ChemPatch possessed good antioxidant and radical scavenging activity, which protected cells in an oxidative microenvironment and improved tissue regeneration. Particularly, ChemPatch acted as a multifunctional barrier and could not only promote reepithelialization and revascularization in wound defect model but simultaneously ameliorate inflammation and prevent postoperative peritoneal adhesion in a mouse cecal defect model. Thus, ChemPatch represents a dual-active bioadhesive barrier for reducing the incidence and severity of peritoneal adhesions.

Risk Factors for Adhesion-Related Readmission and Abdominal Reoperation after Gynecological Surgery: A Nationwide Cohort Study

More than half of women in developed countries undergo surgery during their lifetime, putting them at risk of adhesion-related complications. Adhesion-related complications include small bowel obstruction, chronic (pelvic) pain, subfertility, and complications associated with adhesiolysis during reoperation. The aim of this study is to predict the risk for adhesion-related readmission and reoperation after gynecological surgery. A Scottish nationwide retrospective cohort study was conducted including all women undergoing a gynecological procedure as their initial abdominal or pelvic operation between 1 June 2009 and 30 June 2011, with a five-year follow-up. Prediction models for two- and five-year risk of adhesion-related readmission and reoperation were constructed and visualized using nomograms. To evaluate the reliability of the created prediction model, internal cross-validation was performed using bootstrap methods. During the study period, 18,452 women were operated on, and 2719 (14.7%) of them were readmitted for reasons possibly related to adhesions. A total of 2679 (14.5%) women underwent reoperation. Risk factors for adhesion-related readmission were younger age, malignancy as indication, intra-abdominal infection, previous radiotherapy, application of a mesh, and concomitant inflammatory bowel disease. Transvaginal surgery was associated with a lower risk of adhesion-related complications as compared to laparoscopic or open surgeries. The prediction model for both readmissions and reoperations had moderate predictive reliability (c-statistics 0.711 and 0.651). This study identified risk factors for adhesion-related morbidity. The constructed prediction models can guide the targeted use of adhesion prevention methods and preoperative patient information in decision-making.

Efficacy of Daikenchuto in the prevention of bowel obstruction in patients with colorectal cancer undergoing laparoscopic surgery: An observational study using a Japanese administrative claims database

PURPOSE

Daikenchuto is an herbal medicine widely used in Japan without clear evidence to prevent bowel obstruction after abdominal surgery. We evaluated the efficacy of Daikenchuto in laparoscopic surgery for colorectal cancer (CRC).

METHODS

We included patients from the medical claims databases diagnosed with CRC between January 2012 and December 2019 and treated with laparoscopic surgery. We compared the Daikenchuto and control groups to evaluate early bowel obstruction (EBO) events for 1 year. The Daikenchuto group included patients prescribed Daikenchuto on postoperative day (POD) 0 or 1. An EBO event was defined as the use of a nasogastric tube, transnasal ileus tube, endoscopic balloon dilatation, or the requirement of reoperation for bowel obstruction from PODs 1 to 364.

RESULTS

In total, 46,458 patients met the eligibility criteria; 2407 and 44,051 patients were included in the Daikenchuto and control groups, respectively. Some of the patient's characteristics were significantly different between the groups. The frequencies of EBO events in the Daikenchuto and control groups were 5.7% (95% confidence interval: 4.8-6.7) and 4.6% (4.4-4.8), respectively. The most frequent events were nasogastric tube (3.1%, 2.9%) and transnasal ileus tube insertions (1.4%, 0.8%) in the Daikenchuto and control groups, respectively. The hospital stay was significantly shorter in the Daikenchuto group than in the control; this trend was confirmed in the sensitivity analysis.

CONCLUSIONS

Daikenchuto did not demonstrate efficacy for EBO. It might be adequate for shortening patient's hospital stay. Further studies are warranted.

İntrabdominal Adezyon Oluşum Mekanizmalarına ve Tedavi Stratejilerine Histopatolojik Bakış

Hayat standartlarını olumsuz etkileyen abdominal adezyonlar, postoperatif dönemde görülen önemli bir sağlık sorunudur. Peritoneal kavite ve serozal yüzeylerde oluşan, abdominal travmalara sebep olan kimyasal ve termal faktörler ya da enfeksiyon ve yabancı cisim reaksiyonları adezyon oluşumuna sebep olabilir. Abdominal adezyonların sınıflandırması genellikle adezyon yoğunluğuna ve prognoz ciddiyetine göre yapılsa da henüz dünya çapında kabul görmüş standart bir sınıflandırma sistemi mevcut değildir. Abdominal adezyonlar ağrı, infertilite, cerrahi sonrası hastanede yatış süresinin uzaması ve ekonomik yük gibi olumsuz sonuçlarla klinik yansımalar gösterir. Sonuç olarak, postoperatif süreçte karşılaşılan adezyonlar ciddi bir sorundur ve adezyon oluşumunu engellemek için ileri çalışmaların laboratuvar ortamından klinik araştırma modellerine uyarlanması gerekmektedir. Bu derleme çalışması intraabdominal adezyon oluşumu, histopatolojisi, derecelendirilmesi, önlenmesi ve klinik önemi ile ilgili literatürü gözden geçirmek için hazırlanmıştır.

Adhesions in abdomino-pelvic surgeries: A real economic impact?

STUDY OBJECTIVE

To evaluate the epidemiologic and economic burden related to adhesions and their complications for the French healthcare system.

DESIGN

A descriptive and economic retrospective analysis.

SETTING

Medicalized information system program (PMSI), national scale of costs.

PATIENTS

Female patients operated on to treat adhesions related complications in 2019.

INTERVENTIONS

All patients with coded adhesiolysis acts were selected in order to identify the characteristics of Diagnosis related groups (DRG) and compare them with the general DRGs. Then, a sub-analysis on surgery types (laparoscopy or open procedures) was performed to evaluate impact adhesions development and Length of Stay. Lastly, direct costs of adhesions for the healthcare system were quantified based upon adhesiolysis acts coded as main diagnosis.

MEASUREMENTS AND MAIN RESULTS

26.387 adhesiolysis procedures were listed in France in 2019 through 8 adhesiolysis acts regrouping open surgeries and laparoscopic procedures. Adhesiolysis was coded in up to 34% in some DRGs for laparoscopic procedures. 1551 (1461 studied in our study) surgeries have been realized in 2019 with main procedure: adhesiolysis. These surgeries were associated with an expense of €4 million for the healthcare system for rehospitalizations and reoperations only. Social costs such as sick leaves, drugs and other cares haven't been taken in consideration.

CONCLUSION

Adhesions related complications represent a massive burden for patients and an expensive problem for society. These difficulties may likely to be reduced by a broader use of antiadhesion barriers, at least in some targeted procedures.

Liquid-Liquid Phase-Separated Hydrogel with Tunable Sol-Gel Transition Behavior as a Hotmelt-Adhesive Postoperative Barrier

Postoperative barriers have been widely used to prevent adhesions. However, there are currently few barriers that satisfy clinical requirements, such as tissue adhesion, operability, and biocompatibility. Inspired by the adhesion system of living organisms, we report a liquid-liquid phase-separated hydrogel as a single-syringe hotmelt-type postoperative barrier. Mixing polyethylene glycol with gelatin formed liquid-liquid phase-separated hydrogels through segregative liquid-liquid phase separation. Incorporation of a liquid-liquid phase-separated system into gelatin can enhance the sol-gel transition temperature to give a hotmelt-adhesive property to hydrogels. Hotmelt-adhesive hydrogels became a sol phase and cohered into tissue gaps when warmed and solidified at body temperature to adhere to soft tissues. The hydrogels exhibited tissue adhesion to large intestine tissues and showed improved mechanical strength, gelation time, and shear-thinning properties. In rat cecum-abdominal adhesion models, it was confirmed that the resulting hydrogels prevented abdominal adhesion and did not prevent tissue regeneration. Hotmelt-adhesive hydrogels with high tissue adhesive properties, operability, and biocompatibility have enormous potential as barriers to prevent postoperative complications.

Collagen Type-I Agent Reduced Postoperative Bowel Adhesions Following Laparoscopic and Robot-Assisted Radical Prostatectomy: A Prospective, Single-Blind Randomized Clinical Trial

This study aimed to compare the anti-adhesive effect of collagen type-I (COL) agent and hyaluronic acid-carboxymethylcellulose (HA/CMC) following laparoscopic and robotic radical prostatectomies. This study was a randomized, controlled, single-blind, multicenter study using COL and HA/CMC in patients who underwent laparoscopic and robotic radical prostatectomies. All patients were randomly assigned to either the COL (n = 66) or HA/CMC (n = 65) group. Viscera slide ultrasound sonography was recorded on the day of surgery (V2) and 12 weeks later (V4). The primary end point was the difference in the excursion distance in the viscera slide ultrasonography between V2 and V4. A total of 131 patients participated in this study. The viscera slide distance in the test and control groups was 1.89 ± 0.49 cm and 1.80 ± 0.45 cm, respectively, at V2 (p = 0.275). The average distance of the viscera slide in the test and control group was 1.59 ± 0.49 cm and 1.64 ± 0.45 cm, respectively at V4 (p = 0.614). None of the patients showed significant adverse effects. This randomized study showed that the efficacy and stability of the gel-type COL anti-adhesion agent are not inferior to those of HA/CMC, of which the properties are established.

Variability in the management of adhesive small bowel obstruction in children

BACKGROUND

This study assessed inter-hospital variability in operative-vs-nonoperative management of pediatric adhesive small bowel obstruction (ASBO).

METHODS

A multi-institutional retrospective study was performed examining patients 1-21 years-of-age presenting with ASBO from 2010 to 2019 utilizing the Pediatric Health Information System. Multivariable mixed-effects logistic regression was performed assessing inter-hospital variability in operative-vs-nonoperative management of ASBO.

RESULTS

Among 6410 pediatric ASBO admissions identified at 46 hospitals, 3,239 (50.5%) underwent surgery during that admission. The hospital-specific rate of surgery ranged from 35.3% (95%CI: 28.5-42.6%) to 74.7% (66.3-81.6%) in the unadjusted model (p < 0.001), and from 35.1% (26.3-45.1%) to 73.9% (66.7-79.9%) in the adjusted model (p < 0.001). Factors associated with operative management for ASBO included admission to a surgical service (OR 2.8 [95%CI: 2.4-3.2], p < 0.001), congenital intestinal and/or rotational anomaly (OR 2.5 [2.1-3.1], p < 0.001), diagnostic workup including advanced abdominal imaging (OR 1.7 [1.5-1.9], p < 0.001), non-emergent admission status (OR 1.5 [1.3-1.8], p < 0.001), and increasing number of complex chronic comorbidities (OR 1.3 [1.2-1.4], p < 0.001). Factors associated with nonoperative management for ASBO included increased hospital-specific annual ASBO volume (OR 0.98 [95%CI: 0.97-0.99], p = 0.002), older age (OR 0.97 [0.96-0.98], p < 0.001), public insurance (OR 0.87 [0.78-0.96], p = 0.008), and presence of coinciding non-intestinal congenital anomalies, neurologic/neuromuscular disease, and/or medical technology dependence (OR 0.57 [95%CI: 0.47-0.68], p < 0.001).

CONCLUSIONS

Rates of surgical intervention for ASBO vary significantly across tertiary children's hospitals in the United States. The variability was independent of patient and hospital characteristics and is likely due to practice variation.

LEVEL OF EVIDENCE

III.

Hotmelt tissue adhesive with supramolecularly-controlled sol-gel transition for preventing postoperative abdominal adhesion

Postoperative adhesion is a serious and frequent complication, but there is currently no reliable anti-adhesive barrier available due to low tissue adhesiveness, undesirable chemical reactions, and poor operability. To overcome these problems, we report a single-syringe hotmelt tissue adhesive that dissolves upon warming over 40 °C and coheres at 37 °C as a postoperative barrier. Tendon-derived gelatin was conjugated with the ureidopyrimidinone unit to supramolecularly control the sol-gel transition behavior. This functionalization improved bulk mechanical strength, tissue-adhesive properties, and stability under physiological conditions through the augmentation of intermolecular hydrogen bonding by ureidopyrimidinone unit. This biocompatible adhesive prevented postoperative adhesion between cecum and abdominal wall in adhesion models of rats. This hotmelt tissue adhesive has enormous potential to prevent postoperative complications and may contribute to minimally invasive surgery. STATEMENT OF SIGNIFICANCE: There is a strong need to develop medical tissue adhesives with high biocompatibility, tissue adhesiveness, and operatability to prevent postoperative complications. In this report, single syringe, hotmelt-type tissue adhesive was developed by controlling sol-gel transition behavior of gelatin through supramolecular approach. The functionalization of gelatin with quadruple hydrogen bonding improved key features necessary for anti-adhesive barrier including bulk mechanical strength, tissue adhesive property, stability under physiological conditions, and anti-adhesive property. The hotmelt tissue adhesive can be used for a sealant, hemostatic reagent, and wound dressing to prevent postoperative complications including delayed bleeding, perforation, and inflammation and contribute to minimally invasive surgery.

Safety, efficacy, and operability of a newly developed absorbable adhesion barrier (GM142) in patients with primary rectal cancer scheduled for diverting ileostomy during laparoscopic surgery: Randomized controlled trial

Aim

The aim of this study was to compare the outcomes of GM142, a newly developed gelatin film with a concave and convex structure to a commercially available conventional film, hyaluronate-carboxymethylcellulose.

Methods

Patients with primary rectal cancer who were scheduled for diverting ileostomy during laparoscopic surgery were eligible for this study. Patients were randomized before surgery and an antiadhesion film was applied under the umbilical incision. The primary outcome was the incidence of adhesion under the midline incision confirmed by second-look surgery for diverting ileostomy closure. The secondary outcomes were the adhesion severity score, the extent of adhesion score, the presence of intestinal obstruction, and the success of all patching.

Results

A total of 146 patients were enrolled. A total of 123 patients were included in the full analysis set. The primary outcome of "no adhesion" was observed in 66.1% in the GM142 group and 55.7% in the conventional film group. The noninferiority of GM142 to conventional film was confirmed (P = .0005). The secondary outcomes were similar between the groups. For the safety evaluation, there were no safety concerns regarding allergic reactions to gelatin or increased gelatin-specific IgE antibody titers.

Conclusions

The noninferiority of GM142 to conventional film was shown. GM142 showed no major safety issues. The clinical safety profiles of GM142 suggested certain physiological benefits of the gelatin film as an adhesion barrier.

Complex assessment of immunosuppression effects in prevention and treatment of adhesive disease, an experiment

The cause of all small bowel obstruction in 60-75% of cases is adhesive development. The first and main method for adhesion prevention is undoubtedly the surgical technique, but the prevention of adhesive development is still actual. We aimed to study macroscopic and microscopic peculiarities of the intestine, peritoneum, and scars of the anterolateral abdominal wall. Also, immunological blood changes were observed in rats with the experimental created adhesive disease on the background of azathioprine introduction. The experiment was conducted on 40 rats divided into 2 subgroups: 20 animals as an experimental group (EG1) and 20 as a control group (CG1). Animals from EG received azathioprine (Moshimerampreparaty named by N.A. Semashko, Russia) in a dosage of 1 mg/100g of weight once a day for the first 3 days (starting from the day of surgery). The control group did not receive any drugs. All 40 rats survived the postoperative period. Rats were removed from the experiment on the 7^th day after the operation. There were significant statistical differences in most indicators between the experimental and control groups. Phagocytic index (PI) was reduced by 4.55 due to the natural reaction of the rat organism to the surgery. Indicators of EG were a slight decrease in leukocytes and lymphocytes by 0.3 and 0.9, respectively, a moderate decrease in T-lymphocytes by no more than 2.0, and a decrease in phagocytic activity by 5.8. Immunosuppression with azathioprine significantly reduced the frequency and severity of the adhesive process of the abdominal cavity. Used in the recommended dose does not significantly inhibit important indicators of immunity and does not affect wound healing processes.

An Injectable Peptide Hydrogel Constructed of Natural Antimicrobial Peptide J-1 and ADP Shows Anti-Infection, Hemostasis, and Antiadhesion Efficacy

Postoperative adhesion is a common complication of abdominal surgery, which always has many adverse effects in patients. At present, there is still a lack of effective treatment measures and materials to prevent adhesion in the clinics. Herein, we report the potential use of J-1-ADP hydrogel formed by natural antimicrobial peptide jelleine-1 (J-1) self-assembling in adenosine diphosphate (ADP) sodium solution to prevent postsurgery adhesion formation. J-1-ADP hydrogel was found to have good antimicrobial activity against the bacteria and fungi tested and can be used to prevent tissue infection, which was thought to be one of the incitements of adhesion. Due to ADP being a platelet-activating factor, J-1-ADP hydrogel showed significant hemostatic activity in vitro verified by whole blood coagulation, plasma coagulation, platelet activation, and platelet adhesion assays. Further, it showed potent hemostatic activity in a mouse liver hemorrhage model. Bleeding was believed to be a cause of the formation of postsurgery adhesion. J-1-ADP hydrogel had a significant antiadhesion effect in a rat side wall defect-cecum abrasion model. In addition, it had good biocompatibility and degradation properties. So the present study may provide an alternative strategy for designing antimicrobial peptide hydrogel material to prevent postoperative adhesion formation in the clinic.

Adhesion-related readmissions after open and laparoscopic colorectal surgery in 16 524 patients

AIM

Colorectal surgery is associated with a high risk of adhesion formation and subsequent complications. Laparoscopic colorectal surgery reduces adhesion formation by 50%; however, the effect on adhesion-related complications is still unknown. This study aims to compare differences in incidence rates of adhesion-related readmissions after laparoscopic and open colorectal surgery.

METHOD

Population data from the Scottish National Health Service were used to identify patients who underwent colorectal surgery between June 2009 and June 2011. Readmissions were registered until December 2017 and categorized as being either directly or possibly related to adhesions, or as reoperations potentially complicated by adhesions. The primary outcome measure was the difference in incidence of directly adhesion-related readmissions between the open and laparoscopic cohort.

RESULTS

Colorectal surgery was performed in 16 524 patients; 4455 (27%) underwent laparoscopic surgery. Patients undergoing laparoscopic surgery were readmitted less frequently for directly adhesion-related complications, 2.4% (95% CI 2.0%-2.8%) versus 7.5% (95% CI 7.1%-7.9%) in the open cohort. Readmissions for possibly adhesion-related complications were less frequent in the laparoscopic cohort, 16.8% (95% CI 15.6%-18.0%) versus 21.7% (95% CI 20.9%-22.5%), as well as reoperations potentially complicated by adhesions, 9.7% (95% CI 8.9%-10.5%) versus 16.9% (95% CI 16.3%-17.5%).

CONCLUSION

Overall, any adhesion-related readmissions occurred in over one in three patients after open colorectal surgery and one in four after laparoscopic colorectal surgery. Compared with open surgery, incidence rates of adhesion-related complications decrease but remain substantial after laparoscopic surgery.

Elucidating the Novel Mechanism of Ligustrazine in Preventing Postoperative Peritoneal Adhesion Formation

Postoperative peritoneal adhesion (PPA) is a major clinical complication after open surgery or laparoscopic procedure. Ligustrazine is the active ingredient extracted from the natural herb Ligusticum chuanxiong Hort, which has promising antiadhesion properties. This study is aimed at revealing the underlying mechanisms of ligustrazine in preventing PPA at molecular and cellular levels. Both rat primary peritoneal mesothelial cells (PMCs) and human PMCs were used for analysis in vitro. Several molecular biological techniques were applied to uncover the potential mechanisms of ligustrazine in preventing PPA. And molecular docking and site-directed mutagenesis assay were used to predict the binding sites of ligustrazine with PPARγ. The bioinformatics analysis was further applied to identify the key pathway in the pathogenesis of PPA. Besides, PPA rodent models were prepared and developed to evaluate the novel ligustrazine nanoparticles in vivo. Ligustrazine could significantly suppress hypoxia-induced PMC functions, such as restricting the production of profibrotic cytokines, inhibiting the expression of migration and adhesion-associated molecules, repressing the expression of cytoskeleton proteins, restricting hypoxia-induced PMCs to obtain myofibroblast-like phenotypes, and reversing ECM remodeling and EMT phenotype transitions by activating PPARγ. The antagonist GW9662 of PPARγ could restore the inhibitory effects of ligustrazine on hypoxia-induced PMC functions. The inhibitor KC7F2 of HIF-1α could repress hypoxia-induced PMC functions, and ligustrazine could downregulate the expression of HIF-1α, which could be reversed by GW9662. And the expression of HIF-1α inhibited by ligustrazine was dramatically reversed after transfection with si-SMRT. The results showed that the benefit of ligustrazine on PMC functions is contributed to the activation of PPARγ on the transrepression of HIF-1α in an SMRT-dependent manner. Molecular docking and site-directed mutagenesis tests uncovered that ligustrazine bound directly to PPARγ, and Val 339/Ile 341 residue was critical for the binding of PPARγ to ligustrazine. Besides, we discovered a novel nanoparticle agent with sustained release behavior, drug delivery efficiency, and good tissue penetration in PPA rodent models. Our study unravels a novel mechanism of ligustrazine in preventing PPA. The findings indicated that ligustrazine is a potential strategy for PPA formation and ligustrazine nanoparticles are promising agents for preclinical application.

Chemically Modified Hyaluronic Acid for Prevention of Post-Surgical Adhesions: New Aspects of Gel Barriers Physical Profiles

This study was conducted to provide information regarding the chemistry—including structure, synthesis, formulation, and mechanical properties—of two types of chemically modified anti-adhesion gels made of hyaluronic acid. Gel A (Hyalobarrier®) and gels B and C (HyaRegen® and MetaRegen®) that are used in postsurgical adhesion prevention. To date, little information is available on their physicochemical attributes. This information is necessary in order to understand the differences in their in vivo behavior. Methods: Comparative analyses were conducted under laboratory-controlled conditions, including measuring the shear viscosity, storage modulus G’, peel strength, and extrusion forces. Results: All polymers exhibited viscoelastic behavior. Polymer A showed a shear viscosity approximately three times larger than both polymers B and C (114 Pa.s−1 vs. 36–38 Pa.s−1) over the shear-rate range measured, indicating a possible better ability to resist flows and potentially remain in place at the site of application in vivo. The results of storage modulus (G’) measurements showed 100 Pa for polymer A and 16 Pa and 20 Pa for polymers B and C, respectively. This translated into a weaker elastic behavior for gels B and C, and a lower ability to resist sudden deformation. The peel test results showed a rupture strength of 72 mN (0.016 lbf) for polymer A, 39.6 mN (0.0089 lbf) for polymer B, and 38.3 mN (0.0086 lbf) for polymers C, indicating possible higher adhesive properties for polymer A. Tests measuring the extrudability of the hyaluronic acid gels in their commercial syringes showed an average extrusion force of 20 N (4.5 lbf) for polymer A, 28 N (6.33 lbf) for polymer B, and 17 N (3.79 lbf) for polymer C. Conclusions: Modified anti-adhesion gels made of hyaluronic acid differed in mechanical properties and concentration. Further clinical studies are needed to confirm whether these differences make one polymer easier to apply during surgery and more likely to stay in place longer after in vivo application, and to determine which is potentially superior in terms of preventing adhesions.

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.

Rapidly Self-Deactivating and Injectable Succinyl Ester-Based Bioadhesives for Postoperative Antiadhesion

Postoperative adhesion not only causes severe complications for patients but also increases their economic burden. Injectable bioadhesives with adhesiveness to tissues can cover irregular wounds and stay stable in situ, which is a promising barrier for antiadhesion. However, the potential tissue adhesion caused by bioadhesives' indiscriminate adhesiveness between normal and wounded tissue is still a problem. Herein, by using poly(ethylene glycol) succinimidyl succinate (PEG-SS) and gelatin, a succinyl ester-based bioadhesive (SEgel) was fabricated with self-deactivating properties for postoperative antiadhesion. Because N-hydroxysuccinimide esters (NHS-esters) were used as the adhesive group, the bioadhesives' side in contact with the tissue built covalent anchors quickly to maintain the stability, but the superficial layer facing outward withstood fast hydrolysis and then lost its adhesion within minutes, avoiding the indiscriminate adhesiveness. In addition, because of the specific degradation behavior of succinyl ester, the SEgel with proper in vivo retention was achieved without the worry of causing foreign body reactions and unexpected tissue adhesion. Both the cecum-sidewall adhesion and hepatic adhesion models showed that the SEgel markedly reduced the severity of tissue adhesion. These results, together with the ease of the preparation process and well-proven biocompatibility of raw materials, revealed that the SEgel might be a promising solution for postoperative antiadhesion.

Transcriptome sequencing analysis of primary fibroblasts: a new insight into postoperative abdominal adhesion

PURPOSE

The specific genes or pathways in fibroblasts responsible for the pathogenesis of postoperative abdominal adhesion (PAA) remain to be elucidated. We aim to provide a new insight into disease mechanisms at the transcriptome level.

METHODS

Male Sprague-Dawley rats were used to establish a PAA model. Primary fibroblasts were separated from normal peritoneal tissue (NF) and postoperative adhesion tissue (PF). RNA sequencing was used to analyze the transcriptome in NF and PF.

RESULTS

One thousand two hundred thirty-five upregulated and 625 downregulated DEGs were identified through RNA-Seq. A pathway enrichment analysis identified distinct enriched biological processes, among which the most prominent was related to immune and inflammatory response and fibrosis. HE staining and Masson's trichrome staining histologically validated the RNA-Seq results. Six hub genes, ITGAM, IL-1β, TNF, IGF1, CSF1R and EGFR were further verified by RT-PCR.

CONCLUSIONS

Our study revealed the roles of the immune and inflammatory responses and fibrosis in the process of PAA. We also found six hub genes that may be potential therapeutic targets for PPA.

Intraperitoneal microbial contamination drives post-surgical peritoneal adhesions by mesothelial EGFR-signaling

Abdominal surgeries are lifesaving procedures but can be complicated by the formation of peritoneal adhesions, intra-abdominal scars that cause intestinal obstruction, pain, infertility, and significant health costs. Despite this burden, the mechanisms underlying adhesion formation remain unclear and no cure exists. Here, we show that contamination of gut microbes increases post-surgical adhesion formation. Using genetic lineage tracing we show that adhesion myofibroblasts arise from the mesothelium. This transformation is driven by epidermal growth factor receptor (EGFR) signaling. The EGFR ligands amphiregulin and heparin-binding epidermal growth factor, are sufficient to induce these changes. Correspondingly, EGFR inhibition leads to a significant reduction of adhesion formation in mice. Adhesions isolated from human patients are enriched in EGFR positive cells of mesothelial origin and human mesothelium shows an increase of mesothelial EGFR expression during bacterial peritonitis. In conclusion, bacterial contamination drives adhesion formation through mesothelial EGFR signaling. This mechanism may represent a therapeutic target for the prevention of adhesions after intra-abdominal surgery.

A new spray-type adhesion barrier (AdSpray) improves condition for surgical treatment in the reversal of Hartmann procedure: A case report

RATIONALE

Hartmann procedure (HP) often causes severe postoperative adhesions in the pelvic space; therefore, the reversal of Hartmann procedure (RHP) is a challenging surgery. A new spray-type antiadhesion agent, AdSpray, has been reported to be useful in three-dimensional fields such as the liver. However, there are no reports of its use in HP. We present a case of a male patient with rectal cancer who underwent laparoscopic HP with AdSpray to prevent postoperative adhesions.

PATIENT CONCERNS

A 52-year-old man presented with melena and constipation.

DIAGNOSIS

Colonoscopy revealed an almost obstructive type II tumor at the rectosigmoid colon, and histopathological examination revealed moderately differentiated adenocarcinoma. Enhanced abdominal computed tomography revealed slightly enlarged regional lymph nodes but no ascites around the tumor, and there was no metastasis to the liver or lungs. Therefore, we diagnosed clinical stage T4aN1bM0 rectosigmoid colon cancer. Intraoperatively, a metastatic tumor of the liver surface and a high degree of valve retention in the oral colon were identified.

INTERVENTIONS

After performing laparoscopic HP with AdSpray, we scheduled a laparoscopic RHP with staged hepatic surgery for synchronous liver metastasis from colorectal cancer 1 month later.

OUTCOMES

No postoperative inflammatory adhesions were observed in the pelvis or around the rectal stump, allowing us to perform RHP by a single-incision laparoscopic surgery from the stoma site without any problem. The operation time for RHP was 80 minutes; the patient was in good general condition after the operation, and he was discharged on postoperative day 7.

LESSONS

In laparoscopic HP, Adspray was easy to use for three-dimensional fields such as the pelvis and effectively prevented postoperative inflammatory adhesions. Thus, RHP may become less risky and be performed more as a minimally invasive surgery.

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.

Analysis of the Clinical Efficacy of Laparoscopy and Hysteroscopy in the Treatment of Tubal-Factor Infertility

Objective: This study aims to investigate the clinical efficacy of laparoscopy and hysteroscopy in the treatment of tubal-factor infertility (TFI) to provide a basis for predicting postoperative pregnancy rates.

Methods: The clinical data of 336 patients who underwent laparoscopy and hysteroscopy for TFI between February 2018 and December 2018 in the Department of Reproductive Gynecology at the First People's Hospital of Yunnan were retrospectively analyzed. After implementing the inclusion and exclusion criteria, 278 patients were included in the study. The patients were grouped according to pelvic adhesions, hydrosalpinx, twisted fallopian tubes, and fimbriae structure. The impact of the extent of fallopian tube diseases on postoperative pregnancy outcomes was analyzed.

Results: Of the 278 patients, 129 got pregnant (pregnancy rate = 46.4%). Pelvic adhesions, hydrosalpinx, twisted/folded fallopian tubes, and damage to the fimbriae of the fallopian tubes were found to affect the natural pregnancy rate after surgery, and it decreased significantly with the aggravation of the disease (P < 0.001). Of the 129 patients who had natural pregnancies, 29 had ectopic pregnancies (ectopic pregnancy rate = 22.48%). Twisted/folded fallopian tubes and damage to the fimbriae structure significantly increased the incidence of postoperative ectopic pregnancy (P < 0.001).

Conclusion: Laparoscopy and hysteroscopy are effective treatments for TFI. Pelvic adhesions, twisted/folded fallopian tubes, hydrosalpinx, and damage to the fimbriae of the fallopian tubes can affect postoperative pregnancy outcomes and lead to failure of a natural pregnancy after the operation. The incidence of ectopic pregnancy increases with the degree of fallopian tube twisting/folding and the degree of damage to the fimbriae of the fallopian tubes.

A stem cell-derived ovarian regenerative patch restores ovarian function and rescues fertility in rats with primary ovarian insufficiency

Rationale: Primary ovarian insufficiency (POI) normally occurs before age 40 and is associated with infertility. Hormone replacement therapy is often prescribed to treat vasomotor symptom, but it cannot restore ovarian function or fertility. Stem cell therapy has been studied for the treatment of POI. However, the application of live stem cells has suffered from drawbacks, such as low cell retention/engraftment rate, risks for tumorigenicity and immunogenicity, and lack of off-the-shelf feasibility. Methods: We developed a therapeutic ovarian regenerative patch (ORP) that composed of clinically relevant hydrolysable scaffolds and synthetic mesenchymal stem cells (synMSCs), which are microparticles encapsulating the secretome from MSCs. The therapeutic potency of ORP was tested in rats with cisplatin induced POI injury. Results:In vitro studies revealed that ORP stimulated proliferation of ovarian somatic cells (OSCs) and inhibited apoptosis under injury stress. In a rat model of POI, implantation of ORP rescued fertility by restoring sexual hormone secretion, estrus cycle duration, and follicle development. Conclusion: ORP represents a cell-free, off-the-shelf, and clinically feasible treatment for POI.

Hyaluronate carboxymethylcellulose sheets for the prevention of adhesive complications: a model-based cost-utility analysis

AIM

Clinical trials suggest that hyaluronate carboxymethylcellulose (HA/CMC) prevents adhesion-related complications after intra-abdominal surgery, but at a high upfront cost. This study evaluated the cost-effectiveness of HA/CMC for patients undergoing curative-intent open colorectal cancer surgery.

METHODS

Using a Markov Monte Carlo microsimulation model, we conducted a cost-utility analysis comparing the cost-effectiveness of HA/CMC at curative-intent open colorectal cancer surgery versus standard management. We considered a scenario where HA/CMC was used at the index operation only, as well as where it was used at the index operation and any subsequent operations. The perspective was that of the third-party payer. Costs and utilities were discounted 1.5% annually, with a 1-month cycle length and 5-year time horizon. Model input data were obtained from a literature review. Outcomes included cost, quality-adjusted life-years (QALYs), small bowel obstructions (SBOs) and operations for SBO.

RESULTS

Using HA/CMC at the index operation results in an incremental cost increase of CA$316 and provides 0.001 additional QALYs, for an incremental cost-effectiveness ratio of CA$310,000 per QALY compared to standard management. In our simulated cohort of 10,000 patients, HA/CMC prevented 460 SBOs and 293 surgeries for SBO. Probabilistic sensitivity analysis found that HA/CMC was cost-effective in 18.5% of iterations, at a cost-effectiveness threshold of CA$50,000 per QALY. Results of the scenario analysis where HA/CMC was used at the index operation and any subsequent operations were similar.

CONCLUSIONS

Hyaluronate carboxymethylcellulose prevents adhesive bowel obstruction after open colorectal cancer surgery but is unlikely to be cost-effective given minimal long-term impact on healthcare costs and QALYs.

Feasibility of the Gastrografin Challenge for Adhesive Small Bowel Obstruction

Purpose: This retrospective study investigated the feasibility, diagnostic, and therapeutic advantages of the gastrografin challenge on patients with adhesive small bowel obstruction (ASBO). Methods: There were 125 patients reviewed who were admitted to the Department of General Surgery at a single institution (September 2018 to August 2019) with a diagnosis related to ASBO. The study population included 100 patients (114 cases) who had received initial conservative management. Patient characteristics and operation rates were compared between the gastrografin challenge success group and failure group, and operation rates and length of hospital stay were compared between the gastrografin challenge group and “non-challenge” group. Results: During the study period, 21 patients with ASBO underwent the gastrografin challenge. The challenge was successful in 17 patients where the bowel obstruction was resolved without the need for surgery. Among patients who failed the challenge, 2 patients underwent adhesiolysis and 2 patients were able to progress their diet avoiding surgery. In patients who underwent surgery (<i>n</i> = 2), the length of hospital stay was significantly shorter in the gastrografin challenge group compared with the “non-challenge” group sub analysis (<i>n</i> = 13 cases; 10.5 vs. 20 days, <i>p</i> = 0.038), indicating that the gastrografin challenge assisted rapid decision-making for surgery. No adverse events were reported for the 21 gastrografin challenges. Conclusion: In patients with ASBO, the gastrografin challenge is an accurate, safe method to determine the need for surgery. In addition, the gastrografin challenge may reduce the length of stay in patients who required surgery for ASBO resolution.