The correlation of adhesions and peritoneal fluid cytokine concentrations: a pilot study

BACKGROUND: Intra-abdominal adhesion formation and reformation after surgery is a significant cause of morbidity. The greatest problem after the surgical removal of adhesions is their reformation. We examined the concentrations of interleukin (IL)-1, IL-6 and tumour necrosis factor (TNF)-alpha in the peritoneal fluid throughout the 48 h post-operative period following adhesiolysis, and correlated the results to the extent of adhesion reformation. METHODS: Peritoneal fluid, collected from eight patients following laparoscopy and again at 12, 36 and 48 h after surgery, was analysed using enzyme-linked immunosorbent assay (IL-1 and IL-6) and bioassay (TNF-alpha). At 48 h, a second look laparoscopy was performed to inspect the pelvis for adhesion formation/reformation. RESULTS: Three patients had adhesion reformation >10% at 48 h after surgery. The mean adhesion score 48 h after adhesiolysis was 5 (range 0-17). The mean reduction in adhesion score was 88% (range 83-100%). Newly formed adhesions were filmy, relatively soft and avascular in nature. Adhesion reformation of >10% was associated with (i) high concentrations of IL-6 at 12 h (P < 0.01) and (ii) high concentrations of IL-1 at 48 h (P < 0.001). CONCLUSIONS: Results from this preliminary study suggest that future treatment strategies for adhesion prevention could be aimed at the control of cellular mediators in the peritoneal fluid during the initial adhesion formation period.     

Evaluation of a sprayable polyethylene glycol adhesion barrier in a porcine efficacy model.

BACKGROUND: The formation of adhesions following pelvic surgery remains one of the leading causes of infertility, small bowel obstruction and re-operation for pelvic pain. A novel hydrophilic polyethylene glycol based adhesion barrier (SprayGel) is formed by simultaneously spraying two liquid precursors onto surgical sites. The liquids polymerize to form a gel that effectively coats and adheres to tissue. After about 5 days, the hydrogel layer is absorbed and subsequently undergoes renal clearance. It is believed that the presence of such a barrier would inhibit the formation of adhesions following surgical insult. METHODS: A porcine adhesion model was developed wherein bilateral uterine horn transection and re-anastomosis, along with peritoneal side wall excision was performed via laparotomy. In each animal (n = 10, including the pilot study) one pelvic side wall was treated with adhesion barrier, while the contralateral side remained untreated. RESULTS: At second look laparoscopy, 90% of the untreated sites had adhesions, compared with 30% of the treated sites (P = 0.006). Also observed were statistically significant reductions in the adhesion extent (P = 0.029) and adhesion severity scores (P = 0.023) at the treated sites. However, if the pilot study was excluded (n = 8) the differences obtained were no longer significant. CONCLUSIONS: Polyethylene glycol (SprayGel) merits further investigation as an effective barrier to the formation of post-operative adhesions in this porcine model.     

The role of monocyte chemotactic protein-1 in intraperitoneal adhesion formation

Abdomino-pelvic adhesions arise from infection, endometriosis, or peritoneal injury during surgery, and represent a significant source of morbidity in women of reproductive age. Monocyte chemotactic protein-1 (MCP-1) plays a role in the chemotaxis of mononuclear cells and fibroblasts in a murine wound repair model. To evaluate the role of MCP- 1 in intraperitoneal adhesion formation, we investigated peritoneal fluid MCP-1 levels of women undergoing laparoscopy. Patients without endometriosis were divided into two groups: normal fertile women undergoing bilateral tubal ligation without intraperitoneal adhesions (n=14) and women with pelvic adhesions (n=8). Patients with endometriosis were arranged into two groups: women with (n=17) and without (n=17) adhesions. Peritoneal fluid MCP-1 levels were quantified using an enzyme-linked immunosorbent assay (ELISA). Peritoneal biopsy samples were immunostained for the detection of MCP-1 protein and macrophages, and were also processed for the presence of MCP-1 mRNA expression. Among women without endometriosis, the median peritoneal fluid MCP-1 level was 144 pg/ml (range 54-261) in women without adhesions and was 336 pg/ml (range 130-2494) in women with adhesions (P=0.01). There was a significant correlation between adhesion scores and MCP-1 levels (r=0.50; P=0.018). Among women with endometriosis, peritoneal fluid MCP-1 levels significantly correlated with the stage of the disease. The presence or absence of adhesions did not significantly affect the peritoneal fluid MCP-1 levels in this group of women. In summary, we have found that women with adhesions have elevated peritoneal fluid MCP-1 levels. However, we were not able to show an incremental effect of adhesions on peritoneal fluid MCP-1 levels of patients with endometriosis. Thus, we conclude that factors besides the intraperitoneal adhesions contribute to the elevated peritoneal fluid MCP-1 levels in patients with endometriosis.      

Intraperitoneal adhesions--an ongoing challenge between biomedical engineering and the life sciences

Peritoneal adhesions remain a relevant clinical problem despite the currently available prophylactic barrier materials. So far, the physical separation of traumatized serosa areas using barriers represents the most important clinical strategy for adhesion prevention. However, the optimal material has not yet been found. Further optimization or pharmacological functionalization of these barriers could give an innovative input for peritoneal adhesion prevention. Therefore, a more complete understanding of pathogenesis is required. On the basis of the pathophysiology of adhesion formation the main barriers currently in clinical practice as well as new innovations are discussed in the present review. Physiologically, mesothelial cells play a decisive role in providing a frictionless gliding surface on the serosa. Adhesion formation results from a cascade of events and is regulated by a variety of cellular and humoral factors. The main clinically applied strategy for adhesion prevention is based on the use of liquid or solid adhesion barriers to separate physically any denuded tissue. Both animal and human trials have not yet been able to identify the optimal barrier to prevent adhesion formation in a sustainable way. Therefore, further developments are required for effective prevention of postoperative adhesion formation. To reach this goal the combination of structural modification and pharmacological functionalization of barrier materials should be addressed. Achieving this aim requires the interaction between basic research, materials science and clinical expertise.     

Post-operative consequences of glove powder used pre-operatively in the vagina in the rabbit model

This study was undertaken to determine if a retrograde migration of glove powder (Biosorb(TM)) from the vagina into the abdominal cavity in combination with a subsequent intra-abdominal trauma could affect the development of adhesions. A rabbit model was used with one control and one test group. A total of 50 mg Biosorb(TM) was deposited intravaginally in the test cases before ovulation was induced. Three days later a laparotomy with a small standardized surgical trauma was carried out on the left Fallopian tube and the ipsilateral peritoneum. Ten days later the extent of intra-abdominal adhesions was evaluated. The presence of starch particles in cell smears and biopsies was also investigated. Significant differences in the formation of adhesions were found between the control and the test cases (P < 0.001). In the test group there were dense adhesions and in four cases the Fallopian tube was completely attached to the peritoneal wall. In the control cases only loose minor adhesions were found. This study indicates that the number of starch particles migrating from the vagina to the abdominal cavity is sufficient to enhance significantly the formation of post-operative adhesions. We therefore suggest that powder-free medical or surgical gloves should be used in obstetrics and gynaecology.     

A thermosensitive chitosan-based hydrogel barrier for post-operative adhesions' prevention

Post-operative peritoneal adhesions are common and serious complications for surgeons. They can cause pelvic pain, infertility, and potentially lethal bowel obstruction. We synthesized injectable hydrogels that formed by chemical modification through grafted hydrobutyl groups to chitosan chains. Gelation of hydroxybutyl chitosan (HBC) occurs in less than 60 s. Once formed, it can also be recovered completely. The residue time of hydrogels can extend to 4 weeks in Kunming mice. HBC hydrogels showed mild cytotoxicity to mice fibroblast cell (L929) and human vascular endothelial cell (ECV-304) in vitro and were biocompatible in the murine muscles, causing no adhesions for 4 weeks. HBC gels can form a durable barrier between defected cecum and abdominal wall. In a mice sidewall defect-bowel abrasion model, HBC gels showed significant efficacy in reducing adhesion formation.     

Peritoneal adhesion prevention with an in situ cross-linkable hyaluronan gel containing tissue-type plasminogen activator in a rabbit repeated-injury model

Postoperative peritoneal adhesions can have serious, potentially lethal consequences. Pharmacotherapy and barrier devices can reduce adhesion formation to varying degrees, but their efficacy is limited by rapid clearance from the peritoneum and lack of biological activity, respectively. To overcome these limitations, we have delivered tissue-type plasminogen activator (tPA), which is deficient in the first 2-3 postoperative days, using a highly cross-linked in situ forming hyaluronan gel (HAX(hx)). We demonstrated this formulation's anti-adhesion activity in a rigorous animal model that involved recurrent adhesions. While non-treated or saline-treated animals developed widespread adhesions (frequency, both 100%; median adhesion area, 12.7 and 15.4 cm(2), respectively), tPA delivered by HAX(hx) (tPA-HAX(hx)) was highly effective in preventing recurrent adhesions (frequency, 44%; median adhesion area, 0.1cm(2)). HAX(hx) itself, tPA solution, and inactivated tPA in HAX(hx) did not provide comparable anti-adhesion activity. tPA-HAX(hx) is a system that is easy to use and potentially promising for adhesion prevention.     

Growth of nerve fibres into murine peritoneal adhesions

Adhesions in the peritoneal cavity have been implicated in the cause of intestinal obstruction and infertility, but their role in the aetiology of chronic pelvic pain is unclear. Nerves have been demonstrated in human pelvic adhesions, but the presence of pain-conducting fibres has not been established. The purpose of this study was to use an animal model to examine the growth of nerves during adhesion formation at various times following injury and to characterize the types of fibres present. Adhesions were generated in mice by injuring the surface of the caecum and adjacent abdominal wall, with apposition. At 1-8 weeks post-surgery, adhesions were processed and nerve fibres characterized histologically, immunohistochemically, and ultrastructurally. Peritoneal adhesions had consistently formed by 1 week after surgery and from 2 weeks onwards, all adhesions contained some nerve fibres which were synaptophysin, calcitonin gene-related peptide, and substance P-immunoreactive, and were seen to originate from the caecum. By 4 weeks post-surgery, nerve fibres were found to originate from both the caecum and the abdominal wall, and as demonstrated by acetylcholinesterase histochemistry, many traversed the entire adhesion. Ultrastructural analysis showed both myelinated and non-myelinated nerve fibres within the adhesion. This study provides the first direct evidence for the growth of sensory nerve fibres within abdominal visceral adhesions in a murine model and suggests that there may be nerve fibres involved in the conduction of pain stimuli.     

Postoperative adhesion prevention with low-dose aspirin: effect through the selective inhibition of thromboxane production

The aim of the present study was to evaluate the efficacy of low-dose versus high-dose aspirin in the prevention of postoperative adhesion formation. Forty New Zealand White rabbits were randomized into three groups: low-dose aspirin (1.7 mg/kg per day for 5 days starting on the day of surgery), high-dose aspirin (28.0 mg/kg per day), and controls. The rabbits underwent a standardized surgical injury on the ovary, uterine horn and abdominal wall on one side at laparotomy. On postoperative day 21, a second-look laparotomy was performed for the evaluation of postoperative adhesions. In five animals in each group, peritoneal fluid samples were collected at initial surgery, then through an additional 2 cm incision performed on postoperative day 3, and at second-look laparotomy. The peritoneal concentrations of thromboxane B2 and 6-keto-prostaglandin F1alpha (the stable hydrolysis product of prostacyclin) were measured by radioimmunoassay. At second- look laparotomy, the adhesion formation rate was 46% in the low-dose aspirin group, 77% in the high-dose group, and 100% in the control group. The adhesion score in the low-dose group was significantly lower (P < 0.01) than in the high-dose and control groups. Peritoneal thromboxane decreased significantly during treatment in both low-dose and high-dose aspirin groups, whereas prostacyclin decreased only in the high-dose group. Postoperative adhesion reduction observed in this study with low-dose aspirin treatment could be due to the selective inhibition of thromboxane over prostacyclin production.      

High Reproducibility of Adhesion Formation in Rat with Meso-Stitch Approximation of Injured Cecum and Abdominal Wall

Objective: Peritoneal adhesions following surgery are a common, serious pathology with severe complications. Appropriate animal adhesion models are essential for the assessment of adhesion preventing medical devices. This study introduces a variation of an established rat model in which highest degree adhesions are induced with excellent reproducibility (OPAM = optimized peritoneal adhesion model). Thus, this model seems to be eligible to study effects of adhesion preventing devices.Methods: 24 Lewis male rats were divided into four groups (OPAM, WSFX, sham-OPAM, sham-WSFX). The OPAM technique comprised cecal abrasion, creation of an abdominal wall defect plus approximation of injured areas by a suture, which was compared to a setting of lesions without suture fixation (WSFX). All rats were sacrificed at day 7. Macroscopic and histopathological evaluations were performed. Results were statistically analyzed using ANOVA and Dunnett''s test.Results: In OPAM rats macroscopic analyses revealed a 90% incidence adhesion of cecum to the abdominal wall, all adhesions imposing as complete agglutination. In WSFX animals incidence of adhesions formation was 75%, while in both sham groups there were no adhesions at all. Histology showed the structure of adhesions with merged smooth muscle of colon and skeletal muscle of abdominal wall in all cases.Conclusion: OPAM technique provides adhesions of injured areas with a better probability than with conventional methods. All OPAM adhesions impressed as highest degree adhesions, i.e. agglutination. Due to high reproducibility in incidence and extend of adhesion formation, the OPAM is recommended for testing of adhesion prevention medical devices.     

不同壳聚糖材料预防腹膜粘连的动物研究

为探讨不同壳聚糖材料对预防大鼠腹膜粘连的作用及机理,将240只大鼠分成两大组:壳聚糖凝胶组(A组)和壳聚糖/明胶共混膜组(B组)。A组144只随机分成3组,各组再分成对照组和实验组,用不同的方法致腹膜粘连,实验组用壳聚糖凝胶来预防粘连。B组96只,随机分成4组,每组24只,均行创伤法致腹膜粘连处理,其中1组为对照组,其余3组的创面分别用不同明胶含量的壳聚糖膜覆盖。术后2 w、4 w评定粘连程度并取相应组织作病理学检查。实验表明:(1)壳聚糖凝胶对创伤及缺血所致的腹膜粘连有明显的预防作用;(2)壳聚糖膜和壳聚糖/明胶共混膜都可加重腹膜粘连。     

Peritoneal application of chitosan and UV-cross-linkable chitosan

The suitability of chitosan and UV-cross-linkable chitosan for intraperitoneal use, for example as a barrier device for preventing peritoneal adhesions or for drug delivery, was examined. In vitro experiments using two major cell types present in the peritoneal cavity (mesothelial cells and peritoneal macrophages) revealed neither attractive interactions between cross-linked chitosan gels and the cells nor a proliferative effect. However, the same UV-cross-linked chitosan applied in the peritoneal cavity of rabbits caused a granulomatous reaction with adhesion formation within two weeks in all animals, which persisted up to 4 weeks after exposure. Unmodified chitosan also caused adhesions, while UV irradiation did not. UV-cross-linkable chitosan induced significant elevations in MIP-2 and TNF-alpha from peritoneal macrophages, suggesting that soluble mediators could play a role in inducing adhesion formation. These results reinforce the view that the predictive value of in vitro cytotoxicity assays in matters of biocompatibility may not be sufficient, and suggest that other assays such as cytokine levels may be of value in predicting outcomes in situations involving multiple cell types (i.e. in vivo).     

IL-1, IL-6 and TNF-alpha concentrations in the peritoneal fluid of women with pelvic adhesions.

BACKGROUND: Pelvic adhesions are a significant cause of morbidity and are associated with infertility and pain. The three pro-inflammatory cytokines interleukin (IL)-1, IL-6 and tumour necrosis factor (TNF)-alpha are involved in adhesion formation/reformation. METHODS: The concentration of these three cytokines was examined in the peritoneal fluid of women undergoing laparoscopy, in order to examine the factors affecting their concentrations, with specific reference to the presence or absence of adhesions. RESULTS: We found that the concentration of TNF-alpha in the peritoneal fluid was significantly correlated to the menstrual cycle day (P < 0.01), with increasing concentration as the menstrual cycle progressed from the follicular to the luteal phase. In contrast, IL-1 and IL-6 levels did not show any variation throughout the menstrual cycle. Increased TNF-alpha was found in patients with pelvic adhesions compared with those with normal pelvis; the concentration of TNF-alpha was highest in mild compared with severe adhesions. In contrast, IL-1 concentration was higher in the presence of severe adhesions. IL-6 levels were significantly correlated with the grade of endometriosis (P < 0.05), but there were no significant correlations of either TNF-alpha or IL-1 concentrations with the various grades of endometriosis. CONCLUSION: The exact role of TNF-alpha and IL-1 in adhesion formation is still unknown, but the results from this study suggest that their concentration in the peritoneal fluid is associated with the degree of adhesions present.     

Effectiveness of auto-crosslinked hyaluronic acid gel in the prevention of intrauterine adhesions after hysteroscopic surgery: a prospective, randomized, controlled study

BACKGROUND: A prospective, randomized, controlled study was performed to assess the efficacy of auto-crosslinked hyaluronic acid (ACP) gel to prevent the development of de-novo intrauterine adhesions following hysteroscopic surgery. METHODS: One hundred and thirty-two patients with a single surgically remediable intrauterine lesion (myomas, polyps and uterine septa, subgroups I-III) completed the study. Patients were randomized to two different groups: group A underwent hysteroscopic surgery plus intrauterine application of ACP gel (10 ml) while group B underwent hysteroscopic surgery alone (control group). The rate of adhesion formation and the adhesion score was calculated for each group and subgroup 3 months after surgery. RESULTS: Group A showed a significant reduction in the development of de-novo intrauterine adhesions at 3 months follow-up in comparison with the control group. Furthermore, the staging of adhesions showed a significant decrease in adhesion severity in patients treated with ACP gel. CONCLUSIONS: ACP gel significantly reduces the incidence and severity of de-novo formation of intrauterine adhesions after hysteroscopic surgery.     

Mesothelial‐to‐mesenchymal transition in the pathogenesis of post‐surgical peritoneal adhesions

Peritoneal adhesions (PAs) are fibrotic bands formed between bowel loops, solid organs, and the parietal peritoneum, which may appear following surgery, infection or endometriosis. They represent an important health problem with no effective treatment. Mesothelial cells (MCs) line the peritoneal cavity and undergo a mesothelial‐to‐mesenchymal transition (MMT) under pathological conditions, transforming into myofibroblasts, which are abundant in peritoneal fibrotic tissue. The aim of this study was to investigate if peritoneal MCs undergo a MMT contributing to the formation of post‐surgical adhesions. Biopsies from patients with PAs were analysed by immunohistochemistry, immunofluorescence, and quantitative RT‐PCR. A mouse model of PAs based on ischaemic buttons was used to modulate MMT by blocking the transforming growth factor‐beta (TGF‐β) pathway. The severity of adhesions and MMT‐related marker expression were studied. We observed myofibroblasts derived from the conversion of MCs in submesothelial areas of patients with PAs. In addition, MMT‐related markers were dysregulated in adhesion zones when compared to distant normal peritoneal tissue of the same patient. In animal experiments, blockage of TGF‐β resulted in molecular reprogramming of markers related to the mesenchymal conversion of MCs and in a significant decrease in the severity of the adhesions. These data indicate for the first time that MMT is involved in PA pathogenesis. This finding opens new therapeutic strategies to interfere with adhesion formation by modulating MMT with a wide range of pharmacological agents. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

The impact of peritoneal trauma on intra-abdominal fibrinolytic activity, adhesion formation and early embryonic development in a rabbit longitudinal model

Intra-abdominal adhesions may interfere with fertility following gynaecological surgery and injury to the peritoneum plays a central role in the pathogenesis. Tissue plasminogen activator and its antagonists play a pivotal role in the intra-abdominal balance between fibrinolysis and adhesion formation. This process may be cycle-dependent in women. In order to establish the impact of the fibrinolytic activity on adhesion formation after a standardized trauma, a rabbit longitudinal model was developed, which allowed the study of possible differences between the periods before and after ovulation. The influence of extra-genital adhesions on early embryonic development was investigated. No cycle-dependent changes in fibrinolytic activity of the peritoneal fluid (PF) or of the serum could be demonstrated. No correlation was found between post-operative adhesion formation and the fibrinolytic activity during surgery. Three weeks after surgery, a significant increase in fibrinolytic activity of the PF was observed. The rank order of sampling is suggested to account for these differences. Extra-genital adhesions did not markedly influence ovulation, ovum pick-up and fertilization in this hormonally controlled rabbit model.     

Adhesion formation to hemostatic agents and its reduction with a sodium hyaluronate/carboxymethylcellulose adhesion barrier

The impact of hemostatic agents on postoperative adhesion formation has not been well studied. We hypothesized that hemostatic agents would be a significant nidus for adhesion formation and that a resorbable barrier would effectively reduce adhesions to hemostatic agents. Four commercial hemostatic agents, each composed of a different biomaterial matrix, were implanted in female Sprague-Dawley rats, and adhesion formation was examined 7 days after surgery. In separate studies, the effects of serosal trauma (via cecal abrasion), added blood, and the presence of chemically modified sodium hyaluronate/carboxymethylcellulose (HA/CMC) barrier on adhesion formation to hemostatic agents were studied. Significant adhesions formed to hemostatic agents even in the absence of traumatized tissue. When applied after cecal abrasion, the incidence of adhesions to the hemostatic agents increased. Addition of blood to this model increased adhesion formation even further, causing adhesions in every animal in the study. An HA/CMC adhesion barrier reduced adhesions to hemostatic agents in the presence of serosal trauma and maintained effectiveness even in the presence of blood. In conclusion, hemostatic agents potentiated adhesion formation at the site of application in a model without trauma. In more challenging models, their adhesiogenic contribution was overwhelmed by trauma and blood. HA/CMC adhesion barrier applied over hemostatic agents at the time of surgery provided significant protection against postoperative adhesions in these preclinical models.     

The role of neutrophils in the formation of peritoneal adhesions.

The most common cause of intraperitoneal adhesions which may result in infertility and intestinal obstruction is previous abdominal surgery. Surgical trauma of the peritoneum in the absence of infection elicits a rapid and transient influx of polymorphonuclear leukocytes (PMN) into the peritoneal cavity. The role of neutrophils in intraperitoneal adhesion formation has not been studied. We aimed to study the effects of PMN counts and PMN functions on peritoneal adhesion formation. Forty peritoneal adhesion-induced rats were randomly divided into three groups; group I, receiving saline; group II, receiving cyclophosphamide; and group III, receiving granulocyte-macrophage colony-stimulating factor (GM-CSF). In all groups, peritoneal lavage was performed to determine PMN counts the day after adhesion induction. Blood neutrophil counts and neutrophil functions were also determined. Adhesions were evaluated blindly 14 days after the operation. Adhesion tissue samples were microscopically evaluated. Tissue hydroxyproline and collagen concentrations were measured. The neutrophil counts and phagocytosis significantly increased in group III and neutrophil counts decreased in group II (P < 0.05). The score of adhesion formation in group II was significantly less than that in groups I and III (P < 0.05). Hydroxyproline concentrations of adhesion tissue were significantly decreased in group II when compared with group III (P < 0.05). The present study shows that neutropenia lowers the degree of postoperative adhesion formation. It is concluded that PMN may have a role to play in modulating post-operative adhesion formation.     

Reduction of postoperative adhesions with an auto-crosslinked hyaluronan gel in gynaecological laparoscopic surgery: a blinded, controlled, randomized, multicentre study

BACKGROUND: Following myomectomy, postoperative adhesions occur in many patients with adverse effects on fertility. This study investigated the applicability, safety and efficacy of an auto-crosslinked hyaluronan gel in preventing adhesion formation after laparoscopic myomectomy. METHODS: Fifty-two patients aged 22-42 years, undergoing surgery at four centres, were randomly allocated to receive either the gel or no adhesion prevention. The incidence and severity of postoperative adhesions were assessed laparoscopically after 12-14 weeks in a blinded, scored fashion. The primary efficacy variable was the presence/absence of postoperative adhesions at second-look. RESULTS: A nonsignificantly higher proportion of patients receiving the gel were free from adhesions (13 of 21; 62%) compared with control patients (9 of 22; 41%), with a statistically significant difference between the severity of uterine adhesions at baseline and at second-look (0.3 +/- 0.9 versus 0.8 +/- 1.0, P < 0.05). In subjects undergoing myomectomy without concomitant surgery, the proportion of adhesion-free patients was 8 of 12 (67%) and 4 of 11 (36%) (not significant) in the gel and control groups, respectively, with a significant difference in the mean severity scores (P < 0.05). In subjects without uterine adhesions before myomectomy, 12 of 18 (67%) and 8 of 20 (40%) patients in the gel and control groups, respectively were adhesion-free (not significant), with a significant difference in the severity of uterine adhesions (P = 0.05). CONCLUSIONS: Our results suggest that the auto-crosslinked hyaluronan gel may have a favourable safety profile and efficacious antiadhesive action following laparoscopic myomectomy.     

Human peritoneal adhesions are highly cellular, innervated, and vascularized

Peritoneal adhesions are a major complication of healing following surgery or infection and can lead to conditions such as intestinal obstruction, infertility, and chronic pain. Mature adhesions are the result of aberrant peritoneal healing and historically have been thought to consist of non-functional scar tissue. The aim of the present study was to analyse the cellular composition, vascularity, and extracellular matrix distribution of human peritoneal adhesions, to determine whether adhesions represent redundant scar tissue or are dynamic regenerating structures. Furthermore, the histological appearance of each adhesion was correlated with the clinical history of the patient, to determine whether maturity or intraperitoneal pathology influences adhesion structure. Human peritoneal adhesions were collected from 29 patients undergoing laparotomy for various conditions and were prepared for histology, immunocytochemistry, and transmission electron microscopy. All adhesions were highly vascularized, containing well-developed arterioles, venules, and capillaries. Nerve fibres, with both myelinated and non-myelinated axons, were present in adhesions from nearly two-thirds of the patients, with increased incidence in those with a malignancy. Approximately one-third of the adhesions contained conspicuous smooth muscle cell clusters lined by collagen fibres of heterogeneous size. Adipose tissue was a consistent feature of all the adhesions, with some areas displaying fibrosis. There appeared to be no correlation between the estimated maturity or site of each adhesion and its histological appearance. However, intraperitoneal pathology at the time of surgery did influence the incidence of some histological features, such as the presence of nerve fibres, clusters of smooth muscle cells, and inflammation. This study challenges previous concepts that adhesions represent non-functional scar tissue and clearly demonstrates that established adhesions are highly cellular, vascularized, and innervated, features more consistent with dynamic, regenerating structures.