The Future of Adhesion Prophylaxis Trials in Abdominal Surgery: An Expert Global Consensus

Dual-Polymer Carboxymethyl Cellulose and Poly(Ethylene Oxide)-Based Gels for the Prevention of Postsurgical Adhesions

Postsurgical adhesions are a common complication associated with surgical procedures; they not only impact the patient's well-being but also impose a financial burden due to medical expenses required for reoperative surgeries or adhesiolysis. Adhesions can range from a filmy, fibrinous, or fibrous vascular band to a cohesive attachment, and they can form in diverse anatomical locations such as the peritoneum, pericardium, endometrium, tendons, synovium, and epidural and pleural spaces. Numerous strategies have been explored to minimize the occurrence of postsurgical adhesions. These strategies include surgical approaches, adhesiolysis, antiadhesive agents, and mechanical barriers which have demonstrated the most promise in terms of efficacy and breadth of indications. In this review, we discuss the use of physical/mechanical barriers for adhesion prevention and outline the most commonly used, commercially available barriers. We then focus on a synthetic, dual-polymer gel composed of carboxymethyl cellulose (CMC) and poly(ethylene oxide) [PEO], which, unlike the more commonly used single-polymer hydrogels, has demonstrated higher efficacy across a greater range of indications and surgical procedures. We review the formulation, mechanical properties, and mechanisms of action of the CMC + PEO dual-polymer gel and summarize findings from clinical studies that have assessed the efficacy of CMC + PEO gels in multiple surgical settings in clinics across the world. In conclusion, the CMC + PEO dual-polymer gel represents an approach to preventing postsurgical adhesions that has been commonly used over the last 20 years and could therefore serve as a foundation for research into improving postsurgical outcomes as well as a drug delivery device to expand the use of gels in surgical settings.

Self-Cross-Linked Hyaluronic Acid Gel for Adhesion Prophylaxis in Laparoscopic Deep Endometriosis Removal: Safety Report of a Prospective Pilot Study

Background/Objectives: Surgical removal of deep endometriosis lesions is an established method of reducing patient symptoms, but it often results in iatrogenic adhesions that lead to further problems. This pilot study presents the safety evaluation of a novel self-cross-linked hyaluronic acid gel used to reduce adhesions after non-bowel deep endometriosis surgery. Methods: A single cohort, single-center, non-randomized pilot study was conducted in patients diagnosed with non-bowel deep endometriosis who underwent a three-stage treatment regimen consisting of first surgery, hormone therapy and second surgery. The present report is limited to an analysis of the inflammatory parameters, pain and complications occurring within a 72 h period following the initial laparoscopy (FLL) utilizing the anti-adhesion gel. Results: 60 patients (28.48 ± 5.9 years old) were included. 24 h after the intervention, a slight elevation in C-reactive protein levels was observed in 38.33% of cases (0.98 ± 1.46 mg/dL), with a statistically significant difference after FLL (0.98 ± 1.46 mg/dL before FLL vs. 1.03 ± 1.29 mg/dL after FLL; p =< 0.001); there were no patients with levels above 10 mg/dL before or after surgery. 24 h after FLL, 29.33% of patients had a leukocyte count greater than 11 Thous/μL, with a maximum observed value of 16.2 Thous/μL. The count was found to be statistically significantly higher after FLL (6.03 ± 1.91 Thous/μL before FLL vs. 9.15 ± 2.61 Thous/μL after FLL; p =< 0.001). At 72 h post-intervention, postoperative pain was reported in up to 63.33% of cases, and one urinary tract infection with fever occurred but was not considered to be related to the product. No serious adverse events were observed. Conclusions: The results of this exploratory study showed a safe range of inflammatory response within a 24 h period following the application of the novel self-cross-linked hyaluronic acid antiadhesion gel (HyaRegen®) in patients who underwent laparoscopic surgery for non-bowel deep endometriosis.

Current trends in the prevention of adhesions after zone 2 flexor tendon repair

Treating flexor tendon injuries within the digital flexor sheath (commonly referred to as palmar hand zone 2) presents both technical and logistical challenges. Success hinges on striking a delicate balance between safeguarding the surgical repair for tendon healing and initiating early rehabilitation to mitigate the formation of tendon adhesions. Adhesions between tendon slips and between tendons and the flexor sheath impede tendon movement, leading to postoperative stiffness and functional impairment. While current approaches to flexor tendon repair prioritize maximizing tendon strength for early mobilization and adhesion prevention, factors such as pain, swelling, and patient compliance may impede postoperative rehabilitation efforts. Moreover, premature mobilization could risk repair failure, necessitating additional surgical interventions. Pharmacological agents offer a potential avenue for minimizing inflammation and reducing adhesion formation while still promoting normal tendon healing. Although some systemic and local agents have shown promising results in animal studies, their clinical efficacy remains uncertain. Limitations in these studies include the relevance of chosen animal models to human populations and the adequacy of tools and measurement techniques in accurately assessing the impact of adhesions. This article provides an overview of the clinical challenges associated with flexor tendon injuries, discusses current on- and off-label agents aimed at minimizing adhesion formation, and examines investigational models designed to study adhesion reduction after intra-synovial flexor tendon repair. Understanding the clinical problem and experimental models may serve as a catalyst for future research aimed at addressing intra-synovial tendon adhesions following zone 2 flexor tendon repair.

Long-Term Efficacy and Safety of Adhesion Prevention Agents in Abdominal and Pelvic Surgeries: A Systematic Review

This systematic review evaluates the long-term efficacy and safety of adhesion prevention agents in abdominal and pelvic surgeries, synthesizing data from randomized controlled trials and meta-analyses. Adhesions, common postoperative complications, can lead to significant morbidity, including chronic pain, infertility, and bowel obstruction. Various agents, including hyaluronic acid-carboxymethylcellulose films and icodextrin solutions, have been developed to mitigate these risks. Our review highlights that agents like bioresorbable membranes (Seprafilm) and icodextrin significantly reduce the incidence and severity of adhesions, particularly in high-risk surgeries. However, certain complications such as anastomotic leaks and infections are associated with some agents, emphasizing the need for careful consideration in clinical decision-making. Additionally, while these agents reduce postoperative morbidity and enhance recovery, further research is needed to assess their long-term impact, particularly regarding fertility outcomes and chronic pain. This review underscores the importance of integrating adhesion prevention agents into surgical protocols, which has the potential to reduce healthcare costs, improve patient outcomes, and optimize postoperative care pathways. Standardization of adhesion prevention practices could further enhance surgical efficiency and patient recovery, particularly in high-risk patient populations and complex surgeries.

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.

Global recommendations on adhesion prophylaxis in gynaecological laparoscopic surgery

Adhesions are recognised as one of the most common complications of abdominal surgery; their diagnosis and prevention remains a significant unmet need in surgical therapy, affecting negatively a patient's quality of life and healthcare budgets. In addition, postoperative pelvic adhesions pose a high risk of reduced fertility in women of childbearing age. These 2023 Global Recommendations on Adhesion Prevention in Gynaecological Laparoscopic Surgery provide agreed-upon statements to guide clinical practice, with the ultimate goal of improving patient outcomes.

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.

Chitosan-crosslinked polyvinyl alcohol anti-swelling hydrogel designed to prevent abdominal wall adhesion

Abdominal adhesion is a frequent clinical issue with a high incidence rate and consequences following intra-abdominal surgery. Although many anti-adhesion materials have been used in surgical procedures, additional research is still needed to determine which ones have the most robust wet tissue adhesion, the best anti-postoperative adhesion, and the best anti-inflammatory properties. We have developed an excellent tissue adhesion and anti-swelling polyvinyl alcohol-chitosan hydrogel (AS hydrogel). According to in vitro cell testing, AS hydrogel significantly decreased inflammation around cells and exhibited good biocompatibility. Further, we assessed how well AS hydrogel prevented intraperitoneal adhesion using a rabbit model with cecum and abdominal wall injuries. According to the data, AS hydrogel has excellent anti-inflammatory and biodegradability properties compared to the control group. It can also prevent intestinal and abdominal wall injuries from occurring during surgery. Based on these results, hydrogel appears to be a perfect new material to prevent postoperative abdominal wall adhesion.

Perspectives in adhesion prevention in gynaecological surgery

Adhesions are a frequent, clinically relevant, and often costly complication of surgery that can develop in any body location regardless of the type of surgical procedure. Adhesions result from surgical trauma inducing inflammatory and coagulation processes and to date cannot be entirely prevented. However, the extent of adhesion formation can be reduced by using good surgical technique and the use of anti-inflammatory drugs, haemostats, and barrier agents. Strategies are needed in the short-, medium- and longer-term to improve the prevention of adhesions. In the short-term, efforts are needed to increase the awareness amongst surgeons and patients about the potential risks and burden of surgically induced adhesions. To aid this in the medium- term, a risk score to identify patients at high risk of adhesion formation is being developed and validated. Furthermore, available potentially preventive measures need to be highlighted. Both clinical and health economic evaluations need to be undertaken to support the broad adoption of such measures. In the longer- term, a greater understanding of the pathogenic processes leading to the formation of adhesions is needed to help identify effective, future treatments to reliably prevent adhesions from forming and lyse existing ones.

Postoperative Peritoneal Granulomatous Inflammation After the Application of Potato Starch-Based Anti-Adhesive Agent in Laparoscopic Endometriosis Surgery

Background

Endometriosis is a chronic inflammatory oestrogen-dependent disease. It is characterised by elevated inflammatory markers in the peritoneal milieu with subsequent adhesiogenesis. Nowadays, excisional, and ablative surgeries are considered the main treatment of endometriosis, and adhesiolysis is being performed almost routinely during these procedures. Postoperative adhesion formation is a significant concern for many surgeons, especially as endometriosis patients are assumed to be predisposed to adhesiogenesis. In order to minimise adhesiogenesis after endometriosis surgery, the usage of different barrier methods have been discussed in the literature. Recent studies aim to investigate the effect of potato starch preparations on adhesion formation in endometriosis patients.

Objectives

We aim to describe the findings of a second-look laparoscopy on patients who received a starch-based anti-adhesive agent.

Materials and Methods

We present a retrospective case series that included the medical, surgical, and histopathologic data of three patients.

Main outcome measures

Intraperitoneal adhesion formation and peritoneal inflammation.

Results

All three patients had de-novo adhesions during the second-look laparoscopy. Pathological examination revealed noncaseating granulomatosis of the peritoneum in all patients.

Conclusion

The use of potato starch-based agents as a peritoneal adhesion prophylaxis in laparoscopic endometriosis surgery could lead to granulomatous peritoneal inflammation. Correct application by avoiding powder remnants through complete rinsing and transformation to gel seems to be an important factor to avoid this adverse effect.

What is new?

We aim to highlight that potato starch-based anti-adhesive agents similar to the one used in this study could be a cause of adhesiogenesis and peritoneal inflammation.

Techniques for navigating postsurgical adhesions: Insights into mechanisms and future directions

Postsurgical adhesions are a common complication of surgical procedures that can lead to postoperative pain, bowel obstruction, infertility, as well as complications with future procedures. Several agents have been developed to prevent adhesion formation, such as barriers, anti-inflammatory and fibrinolytic agents. The Food and Drug Administration (FDA) has approved the use of physical barrier agents, but they have been associated with conflicting clinical studies and controversy in the clinical utilization of anti-adhesion barriers. In this review, we summarize the human anatomy of the peritoneum, the pathophysiology of adhesion formation, the current prevention agents, as well as the current research progress on adhesion prevention. The early cellular events starting with injured mesothelial cells and incorporating macrophage response have recently been found to be associated with adhesion formation. This may provide the key component for developing future adhesion prevention methods. The current use of physical barriers to separate tissues, such as Seprafilm®, composed of hyaluronic acid and carboxymethylcellulose, can only reduce the risk of adhesion formation at the end stage. Other anti-inflammatory or fibrinolytic agents for preventing adhesions have only been studied within the context of current research models, which is limited by the lack of in-vitro model systems as well as in-depth study of in-vivo models to evaluate the efficiency of anti-adhesion agents. In addition, we explore emerging therapies, such as gene therapy and stem cell-based approaches, that may offer new strategies for preventing adhesion formation. In conclusion, anti-adhesion agents represent a promising approach for reducing the burden of adhesion-related complications in surgical patients. Further research is needed to optimize their use and develop new therapies for this challenging clinical problem.

Postsurgical Adhesions: Is There Any Prophylactic Strategy Really Working?

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.

A Randomized Double-Blind Controlled Proof-of-Concept Study of Alanyl-Glutamine for Reduction of Post-Myomectomy Adhesions

STUDY OBJECTIVE

To test the hypothesis that intraperitoneal instillation of a single bolus dose of l-alanyl-l-glutamine (AG) will reduce the incidence, extent and/or severity of adhesions following myomectomy and establish preliminary safety and tolerability of AG in humans.

DESIGN

Phase 1,2 Randomized, double-blind, placebo-controlled study (DBRCT).

SETTING

Tertiary care gynecology surgical centre.

PATIENTS

Thirty-eight women who underwent myomectomies by laparoscopy (N = 38; AG-19 vs Placebo-19) or laparotomy (N = 10; AG-5 vs Placebo-5) with a scheduled second-look laparoscopy (SLL) 6-8 weeks later. Thirty-two patients in the laparoscopy arm completed SLL.

INTERVENTIONS

Bolus dose of AG or normal saline solution control (0.9% NaCl) administered intraperitoneally immediately prior to suture closure of the laparoscopic ports. The average dose was 170 mL of AG or control based on a dosing scheme of 1 g/kg bodyweight.

MEASUREMENTS

Digital recordings obtained for all procedures. The primary endpoint was reduction in the incidence, severity and extent of post-operative adhesions analyzed by intention-to-treat (ITT) approach. Three independent, blinded reviewers evaluated all operative video recordings to assess presence of adhesions. Post-hoc analysis assessed presence or absence of adhesions in the peritoneal cavity. Secondary endpoints assessed safety and tolerability of AG.

MAIN RESULTS

Administration of AG reduced the incidence, severity and/or extent of post-operative adhesions (p = 0.046). The presence of adhesions in the AG group was lower than in the Control group (p = 0.041). Adhesion improvement was achieved in 15 of 15 (100%) in the AG group versus 5 of 17 (29.6%) in the placebo group. No serious adverse events were reported. No differences in safety parameters were observed.

CONCLUSIONS

Intraperitoneal l-alanyl-l-glutamine reduced adhesion formation in all patients following laparoscopic myomectomy. Complete absence of adhesions was achieved at all abdominal sites in 93% of patients. Results confirm AG's known effects on cellular mechanisms of adhesiogenesis and lay the foundation for new adhesion prophylaxis research and treatment.

Myomectomy in infertile women: More harm than good?

Adhesion formation following gynecological surgery remains a challenge. The adoption of minimally invasive surgical approaches, such as conventional or robotic-assisted laparoscopy combined with meticulous microsurgical principles and the application of adhesion-reducing substances, is able to reduce the risk of de novo adhesion formation but do not eliminate it entirely. Myomectomy is the most adhesiogenic surgical procedure and postoperative adhesions can have a significant impact on the ability to conceive. Therefore, when surgery is performed as infertility treatment, attention should be paid to whether the benefits outweigh the risks. Among several factors, the size and the location of fibroids are the most accountable factors in terms of adhesion development and post surgical infertility; therefore, the search for effective strategies against adhesion formation in this setting is of paramount importance. The purpose of this review is to evaluate the incidence and factors of adhesion formation and the best preventive measures current available.

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

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