Establishing a physical barrier between the peritoneum and the cecum is an effective method to reduce the risk of postoperative abdominal adhesions. Meloxicam (MX), a nonsteroidal anti-inflammatory drug has also been applied to prevent postoperative adhesions. However, its poor water solubility has led to low bioavailability. Herein, we developed an injectable hydrogel as a barrier and drug carrier for simultaneous postoperative adhesion prevention and treatment. A third-generation polyamide-amine dendrimer (G3) was exploited to dynamically combine with MX to increase the solubility and the bioavailability. The formed G3@MX was further used to crosslink with poly-γ-glutamic acid (γ-PGA) to prepare a hydrogel (GP@MX hydrogel) through the amide bonding. In vitro and in vivo experiments evidenced that the hydrogel had good biosafety and biodegradability. More importantly, the prepared hydrogel could control the release of MX, and the released MX is able to inhibit inflammatory responses and balance the fibrinolytic system in the injury tissues in vivo. The tunable rheological and mechanical properties (compressive moduli: from ∼ 57.31 kPa to ∼ 98.68 kPa;) and high anti-oxidant capacity (total free radical scavenging rate of ∼ 94.56 %), in conjunction with their syringeability and biocompatibility, indicate possible opportunities for the development of advanced hydrogels for postoperative tissue adhesions management.

OBJECTIVE: 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.
CONCLUSIONS: 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.

Foreign body ingestion is an infrequent cause of small bowel obstruction and, rarely, perforation. It is a common occurrence among pediatric patients, mentally impaired and the edentulous elderly population majority of which will pass through the gastrointestinal tract uneventfully. The likelihood of complications such as perforation, bleeding or fistula formation increases markedly particularly for sharp, stiff, and elongated objects (i.e. toothpicks, meat bones, pins, and razor blades). Diagnosis can be difficult as frequently patients are incognizant of the nature and time of ingestion. Imaging is commonly non-specific as well. We present an unusual case of a 65-year-old male who had an ileal perforation secondary to a coconut leaf midrib skewer initially presenting as small bowel obstruction. Intraoperatively, adhesions were seen in the ileum with note of the foreign body perforating two bowel loops that was not identified in preoperative imaging. This case highlights the importance of considering atypical causes of small bowel obstruction even in the background of previous surgery. Finally, early recognition, accurate diagnosis, and timely intervention are essential to improve patient outcomes and decrease mortality in such cases.

The current study examines the effects of linalool in preventing postoperative abdominal adhesions. Twenty male Wistar rats were randomly divided into four groups. (1) Sham: in this group, the abdomen was approached, and without any manipulations, it was sutured. (2) Control: rats in this group underwent a surgical procedure to induce adhesions. This involved making three incisions on the right abdominal side and removing a 1×1-cm piece of the peritoneum on the left abdominal side. (3) Treatment groups: these groups underwent the same surgical procedure as the control group to induce adhesions. Animals in these groups received linalool orally with doses of 50 and 100 mg/kg, respectively, for a period of 14 days. Moreover, rats in the sham and control groups received normal saline via gavage for 14 days. The evaluation of TNF-α, TGF-β, VEGF, and caspase 3 was performed using western blot and IHC methods. Furthermore, oxidative stress biomarkers such as MDA, TAC, GSH, and NO were assessed in the peritoneal adhesion tissue. The findings revealed that linalool significantly reduced peritoneal adhesions by reducing TNF-α, TGF-β, VEGF, and caspase 3 levels. Moreover, MDA concentration was significantly decreased, while NO, TAC, and GSH levels were notably increased. Overall, linalool was effective in preventing adhesion formation and reduced inflammation, angiogenesis, apoptosis, and oxidative stress. Therefore, linalool as a potent antioxidant is suggested for reducing postoperative adhesions in rats.

Postoperative peritoneal adhesions occur in the majority of patients undergoing intra-abdominal surgery and are one of the leading causes of hospital re-admission. There is an unmet clinical need for effective anti-adhesive biomaterials, which can be applied evenly across the damaged tissues. We examined three different responsive hydrogel types, i.e. a thermosensitive PLGA-PEG-PLGA, a pH responsive UPy-PEG and a shear-thinning hexapeptide for this purpose. More specifically, their potential to be homogeneously distributed in the peritoneal cavity by high pressure nebulization and prevent peritoneal adhesions was evaluated. Solutions of each polymer type could be successfully nebulized while retaining their responsive gelation behavior in vitro and in vivo. Furthermore, none of the polymers caused in vitro toxicity on SKOV3-IP2 cells. Following intraperitoneal administration, both the PLGA-PEG-PLGA and the hexapeptide hydrogels resulted in local inflammation and fibrosis and failed in preventing peritoneal adhesions 7 days after adhesion induction. In contrast, the pH sensitive UPy-PEG formulation was well tolerated and could significantly reduce the formation of peritoneal adhesions, even outperforming the commercially available Hyalobarrier® as positive control. To conclude, local nebulization of the bioresponsive UPy-PEG hydrogel can be considered as a promising approach to prevent postsurgical peritoneal adhesions.

Postoperative adhesions are a frequent complication encountered after surgical procedures, mainly after intraperitoneal interventions. To this day, the pathophysiological mechanism behind the process of adhesions formation is not completely known. There are many strategies proposed as prophylaxis methods, involving surgical techniques, drugs or materials that prevent adhesions and even state of the art technologies such as nanoparticles or gene therapy. The aim of our review is to present these innovative approaches and techniques for postoperative adhesions prevention. After a thorough scientific database query, we selected 84 articles published in the past 15 years that were relevant to our topic. Despite all the recent groundbreaking discoveries, we are at an early stage of understanding the complexity of the adhesion formation mechanism. Further investigations should be made in order to create an ideal product for safe clinical use for prevention.

BACKGROUND: Intraabdominal adhesions may develop following cesarean delivery and are considered a major concern.
OBJECTIVE: This study aimed to determine the effect of surgeon seniority in evaluating intraabdominal adhesions at cesarean delivery.
METHODS: A prospective study to estimate interrater reliability between surgeons was conducted. Women who underwent cesarean delivery (January-July 2021) in a single tertiary university-affiliated medical center were included. Blinded questionnaires assessing adhesions were completed by the surgeons. Questions were limited to 4 main anatomic sites and 3 possible categories of adhesion (each site was scored between 0 and 2; the sum score range was 0-8). The surgeons were ranked by increasing seniority (1-4) as: (1) junior residents (less than half of residency completed), (2) senior residents (more than half of residency completed), (3) young attending physicians (attending physicians for <10 years), and (4) senior attendings (attending physicians for >10 years). The weighted percentage of agreement was calculated between the 2 surgeons assessing the same adhesions. Scoring differences between the 2 surgeons (senior vs less senior) were also calculated.
RESULTS: A total of 96 pairs of surgeons were included in the study. The sum interrater reliability found in the weighted agreement tests between surgeons was 0.918 (confidence interval, 0.898-0.938). When scoring differences between surgeons (senior vs less senior) were calculated, nonsignificant difference was found (mean sum score difference of 0.09 with a standard deviation of 1.03 in favor of the more experienced surgeon).
CONCLUSIONS: Surgeon seniority does not affect subjective scoring of adhesion reports.

Postoperative adhesions occur widely in various tissues, bringing the risk of secondary surgery and increased medical burden. Hydrogel barriers with Janus-adhesive ability can achieve physical isolation of adjacent tissues and are therefore considered an ideal solution. However, integrating endoscopic delivery convenience and viscoelastic Janus hydrogel formation remains a great challenge. Here, we present a report of the in situ formation of Janus-adhesive hydrogel barrier using a sprayable fast-Janus-gelation (FJG) powder. We first methacrylate the polysaccharide macromolecules to break the intermolecular hydrogen bonds and impart the ability of rapid hydration. FJG powder can rapidly absorb interfacial water and crosslink through borate ester bonds, forming a toughly adhesive viscoelastic hydrogel. The Janus barrier can be simply formed by further hydrating the upper powder with cationic solution. We construct rat models to demonstrate the antiadhesions efficiency of viscoelastic FJG hydrogels in organs with different motion modalities (e.g., intestine, heart, liver). We also developed a low-cost delivery device with a standardized surgical procedure and further validated the feasibility and effectiveness of FJG powder in minimally invasive surgery using a preclinical translational porcine model. Considering the advantages in terms of therapeutic efficacy, clinical convenience, and commercialization, our results reveal the great potential of Janus-gelation powder materials as a next-generation antiadhesions barrier.

Clinically, increasing the peritoneal barrier is an effective adjunct to reducing postoperative peritoneal adhesion. This study presents a facile template for preparing a supramolecular hybrid hydrogel through dynamic covalent cross-linking between carboxymethyl chitosan (CMCS), 2-formylphenylboronic acid (2-FPBA), and quercetin (Que). The as-prepared complex CMCS/2-FPBA/Que (CFQ) hydrogel exhibited favorable antibacterial, anti-inflammatory, and antioxidant effects. A L929 cytotoxicity evaluation confirmed the favorable cytocompatibility of the CFQ hydrogel. The postoperative anti-adhesion ability of the CFQ hydrogel was further evaluated in rats with lateral wall defects and cecal abrasions. Compared with control groups, the tissue adhesion rate was significantly reduced by increasing the Que concentration in all the hydrogel-treated groups. Additionally, the sustained-release time of the C3F0.8Q0.08 hydrogel can exceed 14 days, which is highly desirable for clinical wound treatment. STATEMENT OF SIGNIFICANCE: Postoperative adhesions are a very common postoperative complication that seriously affects the quality of life of patients. The currently commonly used methods for preventing adhesion mainly use degradable barrier materials for physical separation. In this study, we prepared a dual dynamic covalently cross-linked CFQ hydrogel, which is not only degradable and injectable, but also has multiple properties such as antibacterial, antioxidant and anti-inflammatory, which can effectively prevent postoperative adhesion and promote wound healing.

BACKGROUND: Adhesions are the most common cause of long-term morbidity after abdominal surgery and most often cause various forms of intestinal passage disorders ranging from partial obstruction to complete, life-threatening intestinal obstruction. The aim of the present study was to evaluate the protective effect of intraperitoneally administered lipid emulsions on the formation of adhesions in larger animal model, as the lubricating effect of phospholipids and the mechanical barrier of the lipid component are combined with the anti-inflammatory effect of fish oil.
METHODS: Thirty-one female domestic pigs were randomly divided into three groups. At the end of the surgical procedure, a lipid emulsion or saline solution was applied intraperitoneally. After 14 days, an independent macroscopic, histological and immunohistochemical evaluation of the adhesions were performed.
RESULTS: Intraperitoneal administration of lipid emulsions significantly reduced the incidence of intra-abdominal adhesions. Microscopic examination demonstrated a significant reduction in the number of inflammatory elements and the amount of collagen in the adhesions, especially after administration of the fish oil-based emulsion. A simultaneous decrease in neovascularization was observed in the adhesions. Evaluation of the intestinal anastomosis did not reveal significant differences in healing between the groups.
CONCLUSIONS: Intraperitoneal administration of lipid emulsions can reduce the development of postoperative intra-abdominal adhesions by the combined action of phospholipids as important lubricants and lipids as a mechanical barrier. Their effect is caused by a reduction in proinflammatory and profibrotic mediators. At the same time, intraperitoneal administration of lipid emulsions does not impair healing of the anastomosis in larger animal model.