The sticky business of adhesion prevention in minimally invasive gynecologic surgery

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.

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

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

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.

Reproductive and oncological outcomes of fertility-sparing surgery in patients with stage I epithelial ovarian cancer: A systematic review and meta-analysis

OBJECTIVE

We meta-analyzed available evidence on fertility, survival, and cancer recurrence in patients with stage I epithelial ovarian cancer (EOC) after fertility-sparing surgery (FSS).

METHODS

We systematically reviewed PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials to identify studies reporting reproductive and oncological outcomes of patients with stage I EOC who underwent FSS. Random-effects models were used to calculate pooled rates of disease outcomes, along with 95% confidence intervals (CIs). Subgroup and sensitivity analyses were conducted to identify sources of heterogeneity in the data.

RESULTS

We included 23 observational retrospective studies involving 1126 patients. The pooled pregnancy rate was 30% (95% CI, 0.26-0.34), while the pooled natural conception rate was 26% (95% CI, 0.20-0.33). The pooled live birth rate was 27% (95% CI, 0.22-0.32). The pooled rate of EOC recurrence was 12% (95% CI, 0.09-0.14), which did not differ significantly from the rate among patients who underwent radical surgery (odds ratio, 0.77; 95% CI, 0.45-1.33).

CONCLUSIONS

FSS is associated with good oncological outcomes but less than satisfactory reproductive outcomes. All in all, the procedure appears to be a safe alternative to radical surgery for EOC patients who want to preserve fertility.

Utility of the sliding lung sign for the prediction of preoperative intrathoracic adhesions

Background

To assess the potential of the ultrasonographic sliding lung sign to detect severe intrathoracic adhesions before surgery.

Methods

This was a prospective, single-center, observational study including all patients aged 20-89 years undergoing elective thoracic surgery. Patients with pneumothorax, pyothorax, hemothorax, chylothorax, and hydrothorax were excluded. We recorded the ultrasound sliding lung sign, surgical characteristics, and follow-up parameters: past medical history, respiratory function, chest X-ray findings, and computed tomography (CT) findings. Severe intrathoracic adhesion was defined as the need for adhesiolysis requiring more than 30 minutes.

Results

A total of 168 patients consented to participate. All 15 patients without the sliding lung sign had hard severe adhesions [specificity 100%, sensitivity 88.2%, positive predictive value (PPV) 100%, negative predictive value (NPV) 98.7%, and area under curve (AUC) 0.94]. There were two false-negative results, both of which were soft adhesions. Although blunting of the costophrenic (CP) angle, CT findings, past medical history, and restrictive lung disease were identified as significant risk factors of severe intrathoracic adhesion, all areas under the curve were low (0.71, 0.71, 0.69, 0.61, respectively). Thoracotomy frequency, intraoperative bleeding, operative time, and postoperative hospitalization were significantly greater in these patients than in those with non-severe adhesions.

Conclusions

The ultrasound sliding lung sign could be used to predict severe intrathoracic adhesions before surgery. Preoperative confirmation of the ultrasound sliding lung sign is important for planning surgical approaches and implementing appropriate safety management.

Biomaterials to Prevent Post-Operative Adhesion

Surgery is performed to treat various diseases. During the process, the surgical site is healed through self-healing after surgery. Post-operative or tissue adhesion caused by unnecessary contact with the surgical site occurs during the normal healing process. In addition, it has been frequently found in patients who have undergone surgery, and severe adhesion can cause chronic pain and various complications. Therefore, anti-adhesion barriers have been developed using multiple biomaterials to prevent post-operative adhesion. Typically, anti-adhesion barriers are manufactured and sold in numerous forms, such as gels, solutions, and films, but there are no products that can completely prevent post-operative adhesion. These products are generally applied over the surgical site to physically block adhesion to other sites (organs). Many studies have recently been conducted to increase the anti-adhesion effects through various strategies. This article reviews recent research trends in anti-adhesion barriers.

Practical considerations in the use of a porcine model (Sus scrofa domesticus) to assess prevention of postoperative peritubal adhesions

Infertility has been a common postoperative problem caused by peritoneal adhesions. Since several prophylactic agents have recently shown promising preliminary results, more complete studies comparing their real efficacy and safety are needed urgently. The aim of this study was to investigate and describe practical considerations of a porcine model that can be used to assess such prophylactic agents. First, 10 healthy 5½ months old female pigs (24.3-31.3 Kg) underwent a standardized laparoscopy to provoke peritubal adhesion formation without prophylactic agents. After 30 days, a second-look laparoscopy was performed to evaluate adhesions and perform adnexectomy for histopathological evaluation. Adhesions at different sites were classified by grade, for which the scores range from 0 (no adhesion) to 3 (very strong vascularized adhesions), and also by area, with scores ranging from 0 (no adhesion) to 4 (>75% of the injured area). The histopathological evaluation of the distal uterine horns, oviducts and ovaries were compared withthose from a control group of six healthy pigs with no previous surgery. Biological samples were collected to assess vitality, inflammation and renal, hepatic and hematopoietic systems. There were small (but significant) changes in serum albumin (P = 0.07), globulin (P = 0.07), C-reactive protein (P = 0.011), fibrinogen (P = 0.023) and bilirubin (P<0.01) after 30 days, but all values were within the normal range. No inflammation or abscess formation was observed, but different degrees of adhesion were identified. The estimated occurrence of adhesion (scores >0) and of strong / very strong adhesion (scores >1) was 75% (95% CI: 55-94.9) and 65% (95% CI: 45-85), respectively. The porcine model represents a useful animal platform that can be used to test the efficacy and safety of candidate prophylactic agents intended to prevent postoperative peritubal adhesions formation. We present several practical considerations and measures that can help to minimize animal suffering and avoid problems during such experiments.

Outcomes of adhesion barriers in gynecologic surgeries: A retrospective study at a medical center

During second-look surgery or hospitalization, intra-abdominal surgeries may cause severe postoperative complications, such as pelvic adhesion, postoperative ileus, and severe pain. However, only few studies have analyzed the outcomes of antiadhesive barriers in second-look surgery. This retrospective study aims to identify the outcomes of different antiadhesive barriers by analyzing surgical images. The study included patients who received an adhesion barrier during second-look surgery between January 2011 and November 2017. Four brands of adhesive barriers were used: Interceed, Seprafilm, Adept, and SurgiWrap. Adhesion scores were calculated for four quadrants of the uterus and surrounding structures before and after the use of antiadhesive barriers. The differences between the data of 2 observers and surgery times were also determined. A total of 18 patients were enrolled in the study. The adhesion scores were not significantly different before and after the placement of antiadhesive barriers. The difference in the adhesion scores between the two observers was also not significant, except in the Seprafilm group (P = .029). Furthermore, no significant change in the adhesion scores was observed between the first and second surgeries. Therefore, using adhesion barriers may not decrease the adhesion scores in the current setting.

Effect of 4DryField® PH, a Novel Adhesion Barrier, on Recurrence of Intestinal Adhesions after Extensive Visceral Adhesiolysis

Background

Adhesions occur after up to 97% of abdominal interventions causing chronic pain, infertility, and intestinal obstruction. Various concepts to prevent adhesions have been presented but mostly either have low efficacy or are not applicable in resective intestinal surgery or incomplete hemostasis. In this retrospective one-center clinical trial, the course of patients with extensive abdominal adhesiolysis and application of a recent starch-based formulation, 4DryField PH (4DF), is analyzed.

Case Report

Five female patients (age 65–83 years) underwent extensive open adhesiolysis with application of 4DF gel for adhesion prevention, premixed extracorporeally with saline or Ringer's solution (60–70 mL per 5 g 4DF) for homogeneous gel distribution on intestinal loops and in the peritoneal cavity. In addition, dry 4DF powder was dispersed on the greater omentum and subsequently transformed into a gel by dripping with saline or Ringer's solution directly before abdominal closure. Patients were followed up for more than two years, except for one patient who died after nine months due to metastases. One patient with complex situation due to Gore-Tex mesh in the lower abdomen showed no adhesions at scheduled second-look operation but after six months had relaparotomy for adhesiolysis. All other patients have remained free of adhesions or adhesion-related symptoms during follow-up.

Conclusion

Considering the extent and complexity of adhesions, treatment with 4DF gel for adhesion prevention after open adhesiolysis appears promising. Prospective randomized trials should further elaborate on this clinical concept.

A prospective randomized experimental study to investigate the peritoneal adhesion formation after waterjet injection and argon plasma coagulation (HybridAPC) in a rat model

BACKGROUND

This prospective, randomized, controlled, single-blinded study investigates the peritoneal adhesion formation of HybridAPC (waterjet elevation of the peritoneum with subsequent argon plasma coagulation) versus only waterjet (elevation with the same instrument, but without subsequent argon plasma coagulation) in a rat model (24 female Wistar rats).

MATERIALS AND METHODS

Bilateral lesions were created on the abdominal wall with HybridAPC on one sidewall and waterjet elevation on the other sidewall of the peritoneum in a standard fashion. After 10 days, the rats were euthanized to evaluate the peritoneal trauma sites.

MAIN OUTCOME MEASURE(S)

Adhesion incidence, quantity, and quality were scored 10 days postoperatively and studied histopathologically.

RESULT(S)

Incidence of adhesion formation was 2.3% for HybridAPC; no adhesions occurred for peritoneal elevation with saline (p = 1.00). Histologic evaluation revealed no acute inflammation in both groups. An overall moderate degree of granulation tissue formation and myonecrosis was observed in the HybridAPC group, whereas no chronic inflammation and myonecrosis occurred after elevation without thermal ablation (p < 0.0001).

CONCLUSION(S)

This study investigates the effect of waterjet elevation of the peritoneum with and without subsequent thermal ablation on adhesion formation in a rat model for the first time. Peritoneal waterjet elevation with saline does not provide any risk of adhesion formation. Thermal coagulation with APC after waterjet elevation of the peritoneum creates advantageous peritoneal conditions due to a permanent moist tissue surface and the cooling effect of the injected solution, resulting in no significant difference in adhesion formation compared to peritoneal elevation without thermal ablation. HybridAPC can thus be regarded as a beneficial coagulation method with only minor adhesion formation due to positive tissue effects of the combined waterjet.