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.     

Adhesion preventive effect of hyaluronic acid after intraperitoneal surgery in mice.

Prevention of intraperitoneal adhesion after gynaecological surgery is essential for maintaining postoperative fertility. In this study, the adhesion prevention effect was examined of a hyaluronic acid (HA) solution obtained from the fermentation method and having a molecular weight of 1.9x10(6) with high viscosity. Laparotomy was conducted on female mice 7 weeks old, whose menstrual periods were synchronized by pregnant mare serum gonadotrophin (PMSG) to injure the uterine horn surface. Intraperitoneal adhesions were favourably formed in 91.7% of cases induced with iodine abrasion, compared with 50% induced by electrosurgery. Intraperitoneal administration of HA was evaluated for its effect on the prevention of adhesions made by iodine abrasion. Adhesion prevention effects of HA were observed at concentrations of 0.3, 0.5, 0.75 and 1.0%, among which the most pronounced effect was with the use of a 0.3% solution (92.3% of cases). Compared with the control group adhesion score of 2.0 +/- 0. 8, significant decreases in adhesion scores were observed at all concentrations. HA with a molecular weight of 1.9x10(6) was recognized to have a definitive prevention effect on postoperative adhesions in mice after laparotomy and is considered to be a prospective material for future clinical use.     

Comparison of hyaluronate/carboxymethylcellulose membrane and melatonin for prevention of adhesion formation in a rat model

BACKGROUND: To investigate the effectiveness of melatonin in preventing post-operative adhesion formation and to compare it with the efficacy of hyaluronate/carboxymethylcellulose membrane in a rat model. MATERIALS and METHODS: Following pilot studies, 35 rats were operated on in the full study. In 15 animals (group one), 10 standard lesions were inflicted in each uterine horn (total 30 horns) and melatonin was applied before closure of the abdomen. In the second group, 20 animals were operated on and one of the uterine horns (total 20 horns) with standard lesions was treated with hyaluronate/carboxymethylcellulose membrane and the other uterine horn served as a control. Second-look operations were performed 1 week later and adhesion scores were compared. RESULTS: The adhesion scores of uterine horns treated with melatonin and of uterine horns treated with hyaluronate/carboxymethylcellulose membrane were significantly lower than the scores of the controls (P < 0.001). There was no statistically significant difference between the adhesion scores of uterine horns treated with melatonin and of uterine horns treated with hyaluronate/carboxymethylcellulose membrane (P > 0.05). CONCLUSIONS: Both melatonin and hyaluronate/carboxymethylcellulose membrane were effective in prevention of adhesion formation in a rat uterine horn model.     

Prevention of postoperative adhesion formation in rat uterine horn model by nimesulide: a selective COX-2 inhibitor

BACKGROUND: Pelvic surgery is one of the main causes of intraperitoneal (i.p.) adhesions that create various medical problems including pelvic pain, bowel obstructions and female infertility. A rat model was used to investigate the efficacy of nimesulide, a selective cyclooxygenase-2 inhibitor, in the prevention of adhesion formation. METHODS: Fifty Wistar-Albino rats underwent bilateral uterine horn injury with a unipolar cautery. Study groups were as follows: (i) control group, no adjuvant therapy; (ii) i.p. Ringer's lactate group, 2 ml Ringer's lactate solution was instilled i.p.; (iii) i.p. Ringer's lactate plus nimesulide group, 1 ml Ringer's lactate plus 1 ml nimesulide (0.5 mg/ml) were given i.p.; (iv) intramuscular (i.m.) nimesulide group, 1 ml i.m. nimesulide (0.5 mg/ml) was given preoperatively for 5 days; and (v) i.p. nimesulide group, 1 ml nimesulide (0.5 mg/ml) was instilled i.p. At the end of the study all animals were killed, and a standard adhesion scoring system was applied by a blinded examiner. RESULTS: The mean adhesion extent in study groups was as follows: 1.33 +/- 0.76 in control group, 1.40 +/- 0.90 in i.p. Ringer's lactate group, 0.75 +/- 0.70 in i.p. Ringer's lactate plus nimesulide group, 0.25 +/- 0.44 in i.m. nimesulide group and 0.31 +/- 0.70 in i.p. nimesulide group. The mean +/- SD adhesion severities of control, i.p. Ringer's lactate, i.p. Ringer's lactate plus nimesulide, i.m. nimesulide, and i.p. nimesulide groups were 0.58 +/- 0.35, 0.30 +/- 0.41, 0.27 +/- 0.3, 0.12 +/- 0.28 and 0.15 +/- 0.35 respectively. The lowest adhesions were found in the groups treated with nimesulide i.m. and nimesulide i.p. ( P < 0.05). CONCLUSIONS: This study showed that preoperative i.m. or postoperative i.p. administration of nimesulide to the site of injury reduced the formation of postoperative adhesions in a rat uterine horn model.     

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.     

Prevention of abdominal adhesion formation by thermosensitive PECE-hydrogel in a rat uterine horn model

In this work, we investigated the efficacy of PECE-hydrogel in preventing postsurgical peritoneal adhesions in the rat uterine horn model. Standardized surgical traumas were applied to the peritoneum of the abdominal wall and the uterine horns. PECE hydrogel was applied to the two wound surfaces. Animals were euthanized at different times after surgery, and the gross necropsy findings were documented. Adhesion formation was assessed according to adhesion extent and adhesion severity, and the hydrogel degradation and healing of peritoneal wounds were observed. The remesothelialization was dynamically observed by scanning electron microscope. The results showed that none of the animals in the hydrogel-treated group (n = 12) developed adhesion. In contrast, all untreated animals (n = 12) had adhesions that could only be separated by sharp dissection (p < 0.001). The hydrogel could adhere to the peritoneal wounds and gradually disappear from the wounds within 7-9 days and transformed into viscous fluid being completely absorbed within 12 days. The injured parietal and visceral peritoneum was remesothelialized in about 7 and 9 days, respectively. This work confirmed that PECE hydrogel holds promise as a novel absorbable biomaterial for the reduction of postoperative adhesions after laparotomy.     

The mouse as a model to study adhesion formation following endoscopic surgery: a preliminary report.

Our aim was to investigate the feasibility of a mouse model to study adhesion formation following endoscopic surgery. Following preliminary studies to establish anaesthesia and pneumoperitoneum pressure, a prospective randomized study was carried out to investigate the effect of CO2 pneumoperitoneum on postoperative adhesions. In group I (control group), the duration of pneumoperitoneum was shorter than 5 min. In groups II, III and IV, pneumoperitoneum was maintained for 60 min without flow, with a continuous low flow (1 ml/min) and a continuous high flow (10 ml/min) through the abdominal cavities of the mice using non-humidified CO2, respectively. Adhesions were scored after 7 days by laparotomy. The total adhesion scores were 0.9 +/- 0.8 (n = 15) in control group, 2.4 +/- 0.8 (n = 15) (P < 0.001 versus control group) in group II with no flow, 2.6 +/- 1.3 (n = 15) (P < 0.001 versus control group) in group III with a continuous low flow and 4.3 +/- 0.9 (n = 15) (P < 0.001 versus control group and P < 0.001 versus group II and III) in group IV with a continuous high flow. In conclusion, the mouse can be used as a model to study adhesion formation following endoscopic surgery. Duration of CO2 pneumoperitoneum is a co-factor in adhesion formation.     

Oral tadalafil reduces intra-abdominal adhesion reformation in rats

BACKGOUND: Currently, there is no ideal agent to prevent adhesion formation. We have shown that sildenafil, a phosphodiesterase-5 (PDE-5) inhibitor, reduces post-operative adhesion formation by vasodilatation and increases fibrinolytic activity. Here, we evaluated whether tadalafil, a long-acting PDE-5 inhibitor, decreases post-operative adhesion reformation in rats. MATERIALS AND METHODS: Standardized lesions were created in Wistar albino rats by cauterization of uterine horns and abrasion of adjacent peritonium. The extent and severity of adhesions were scored on the 14th post-operative day and adhesiolysis was performed at the second laparotomy. Animals were then assigned randomly into two groups. The study group (n = 11) received 10 mg/kg oral tadalafil by gavage 60 min before the second laparotomy and daily for 14 days afterwards. Controls (n = 11) received the same volume of tap water for 14 days by gavage. Animals were killed 15 days after adhesiolysis and adhesions were scored blind during the third laparotomy. RESULTS Basal adhesion scores at the time of the second laparotomy were comparable in the study and control groups. Scores for the extent of adhesion reformation in the study and control groups did not differ [median 1 (range 0-3) versus median 2 (range 1-3); P: 0.81] but tadalafil reduced the respective severity scores [median 0.5 (range 0-1) versus median 1 (range 0.5-1); P: 0.02] and total scores [median 2 (range 0-4) versus median 2.5 (range 1.5-4); P: 0.042]. CONCLUSIONS: Oral administration of tadalafil during the perioperative period reduces intra-abdominal adhesion reformation in rats.     

The effect of training and duration of surgery on adhesion formation in the rabbit model

In order to evaluate the effect of training upon postoperative adhesions, standard bipolar and mechanical, nonopposing injuries were performed in the uterine horns and side walls of 52 mature female rabbits using a conventional three-puncture laparoscopy, by an endoscopic surgeon with limited experience. An additional injury, either bipolar or mechanical or both, was performed in the retro- uterine space. With experience, the duration of surgery decreased progressively from 12 +/- 2 to 8 +/- 1 min in the first and last 10 animals respectively. The amount of perioperative bleeding was not affected by experience. With experience the postoperative adhesions decreased in extent (P = 0.0001), tenacity (P = 0.004), type (P = 0.002) and inflammation (P = 0.003) and for total score (P = 0.0002). These changes were correlated with the briefer duration of surgery but not with the amount of perioperative bleeding. The strong correlations of adhesion scores in the pouch of Douglas, and around both uterine horns confirmed the importance of the inter-animal variability in making adhesions. By logistic regression, the adhesions in the pouch of Douglas were explained simultaneously by the adhesions on the uterine horns (P = 0.0004, thus correcting for inter-animal variability) by the amount of bleeding (P = 0.01) and the duration of surgery (P = 0.05). No major differences were found in adhesions following a mechanical or a bipolar injury or following such a lesion in the pouch of Douglas or at the uterine horns. In conclusion, experience, expressed by the duration of surgery and to a lesser extent perioperative bleeding, is a major co-factor in postoperative adhesions, suggesting that duration of surgery should be strictly standardized in endoscopic adhesion studies. The important inter-animal variability can be circumvented by using a standard control lesion, making each animal its own control.      

Inhibition of chemokines prevents intraperitoneal adhesions in mice

BACKGROUND: The present study evaluates the efficacy of a broad-spectrumchemokine inhibitor, NR58-3.14.3, in the prevention of adhesionformation after i.p. surgery in mice. METHODS: A total of 110eight week old female Balb/c mice underwent laparotomy. Fortyanimals were randomly assigned to receive daily i.p. injectionsof either vehicle (control) or NR58-3.14.3. Time-course of adhesionformation was assessed. A titration of NR58-3.14.3 was conductedfor i.p. and s.c. administrations. The effectiveness of a singleintra-operative dose of NR58-3.14.3 was evaluated. Number, extent,location and type of adhesions were recorded. Immunohistochemistryof adhesions was done with leukocyte common antigen, CD45. RESULTS:Adhesion scores peaked on post-operative days 6–8. Onboth days 6 and 8, there were smaller adhesion size and lowercumulative adhesion scores in NR58-3.14.3-treated group. Moreover,on day 8, there were significantly fewer adhesions in NR58-3.14.3-treatedgroup compared to controls. The least effective dose for i.p.administration of NR58-3.14.3 was 0.45 mg/animal. Subcutaneousand single intra-operative i.p. administrations were also effectivein the prevention of i.p. adhesions. Although NR58-3.14.3 decreasedthe number of CD45⁺ inflammatory cells in the adhesions by 22.5%compared to control group, this was not significant. CONCLUSIONS:Our results show that this broad-spectrum chemokine inhibitorprevents post-operative adhesions in mice and may have a potentialclinical use.     

A randomized, controlled pilot study of the safety and efficacy of 4% icodextrin solution in the reduction of adhesions following laparoscopic gynaecological surgery

BACKGROUND: Adhesion-related readmissions are frequent sequelae to gynaecological surgery. Attempts to prevent adhesions by separating healing peritoneal surfaces include site-specific barriers and hydroflotation by instilled solutions. Rapid absorption limits the effectiveness of solutions such as Ringer's lactated saline (RLS). This pilot study assessed the safety, tolerability and preliminary effectiveness of a non-viscous, iso-osmolar solution of 4% icodextrin, an alpha-1,4 glucose polymer with prolonged intraperitoneal residence, in reducing adhesions after laparoscopic gynaecological surgery. METHODS: Women aged > or = 18 years, requiring laparoscopic adnexal surgery (n = 62), were entered into a randomized, open-label, assessor-blinded, multicentre study to compare 4% icodextrin with RLS. Treatments were coded in blocks of four with equal randomization to each group, and pre-allocated to consecutively numbered patients. At least 100 ml per 30 min was used for intra-operative lavage, with 1 l instilled post-operatively. Per protocol analysis included all eligible patients (n = 53); reformation analysis required one or more baseline adhesion (n = 42). Incidence, extent and severity of post-operative adhesions were assessed at second-look laparoscopy after 6-12 weeks. Procedures were video-taped for third party, blinded assessment. RESULTS: Safety and tolerability (laboratory variables, adverse events, clinical follow-up) were good with no difference between treatments. A shift analysis of incidence-ranked adhesions (n = 53) showed apparent improvements in more patients with icodextrin than RLS (37 versus 15%; not significant). Adhesion score reduction (n = 42) was more frequent in icodextrin- than RLS-treated patients: incidence (52 versus 32%), extent (52 versus 47%), and severity (65 versus 37%). Despite greater baseline adhesions, median reformation was less after icodextrin (24%) than RLS (60%). The pilot study group sizes were not powered for statistical significance. CONCLUSIONS: In this preliminary study, 4% icodextrin lavage plus instillation was well tolerated and reduced adhesion formation and reformation following laparoscopic gynaecological surgery. A Phase III pivotal study is currently in progress.     

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.     

Endometrial thickness measured by ultrasound scan in women with uterine outlet obstruction due to intrauterine or upper cervical adhesions

BACKGROUND: A subgroup of women with Asherman's syndrome has adhesions of limited extent completely blocking the lower uterine cavity or upper cervix, whereas the upper endometrium remains normal. Haematometra are rarely found in these women. We tested the hypothesis that women with localized adhesions occluding the uterine outlet (but not affecting the upper uterine cavity) will have much thinner endometrium than controls. METHODS: Twenty-six women with Asherman's syndrome (16 with limited outlet adhesions only) and 50 with normal menstrual cycles underwent transvaginal ultrasound scan where endometrial double thickness was measured precisely and the cycle phase assessed. The presence of any fluid in the uterine cavity was noted. RESULTS: The endometrium in women with Asherman's syndrome, in whom uterine outlet blockage was the sole abnormality (subgroup 3), was substantially thinner (mean +/- SEM: 3.9 +/- 0.4 mm) than controls (8.5 +/- 0.05; P < 0.001), and haematometra were very uncommon (1 of 16). Endometrial thickness at all stages of the ovarian/menstrual cycle in all three subgroups of Asherman's syndrome was significantly less than in normal menstruating controls. CONCLUSIONS: Non-invasive ultrasound measurements have demonstrated very thin endometrium and absence of haematometra in most women with uterine outlet occlusion by adhesions. This unusual phenomenon of failure of cyclical endometrial growth and breakdown in the sole presence of cervical occlusion by adhesions merits further study.     

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.     

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

BACKGROUND: A prospective, randomized, controlled study was performed to assess the efficacy of auto-cross-linked hyaluronic acid (ACP) gel in preventing the development of intrauterine adhesions following hysteroscopic adhesiolysis. METHODS: Ninety-two patients with irregular menses and intrauterine adhesions referred to the Hysteroscopic Unit of the University of Naples "Federico II". Patients were randomized to two different groups. Group A were randomized to hysteroscopic adhesiolysis plus intrauterine application of ACP gel (10 ml) and group B were randomized to operative hysteroscopy alone (control group). Baseline adhesion scores were calculated for each patient and at 3 months after surgery. RESULTS: Group A showed a significant decrease in intrauterine adhesions at 3 months follow-up in comparison with the control group. Staging of adhesions showed a significant decrease in adhesion severity in patients treated with ACP gel. CONCLUSIONS: ACP gel significantly reduces the development of intrauterine adhesions postoperatively and its use is likely to be associated with a reduction of severe adhesions.     

Indices of low-grade chronic inflammation in polycystic ovary syndrome and the beneficial effect of metformin

BACKGROUND: Women with polycystic ovary syndrome (PCOS) have an increased prevalence of insulin resistance (IR) and related disorders. Elevated serum levels of cellular adhesion molecules (CAMs) reflect low-grade chronic inflammation and have been associated with several insulin-resistant states. The objective of this study is to investigate whether soluble inflammatory markers [soluble intercellular adhesion molecule-1 (sICAM-1), soluble endothelial leukocyte adhesion molecule-1 (sE-selectin), soluble vascular cell adhesion molecule-1 (sVCAM-1) and C-reactive protein (CRP)] are altered in PCOS and to further elucidate the effect of metformin treatment on their levels. METHODS: Two young populations were studied [62 women with PCOS and 45 normal women of similar age, BMI and waist-to-hip ratio (WHR)]. Plasma levels of sICAM-1, sVCAM-1, sE-selectin and high-sensitivity CRP (hsCRP) were measured in both groups. Additionally, the effect of metformin on these molecules was investigated in 22 women with PCOS who accepted to metformin protocol (1700 mg daily for a 6-month period). RESULTS: In the total population studied, plasma levels of hsCRP (mg/l), sICAM-1 (ng/ml) and sE-selectin (ng/ml) were higher in the PCOS group compared with those in controls (hsCRP 1.31 +/- 0.22 versus 0.92 +/- 0.27, P = 0.014, sICAM-1 301.21 +/- 24.80 versus 209.86 +/- 17.05, P = 0.025, sE-selectin 57.37 +/- 4.08 versus 45.67 +/- 4.62, P = 0.045, respectively). sVCAM-1 (ng/ml) did not differ statistically among the two groups (P = 0.896). A significant reduction in hsCRP and sVCAM-1 was achieved after 6 months of metformin administration: PCOS pretreatment hsCRP 1.92 +/- 0.60 versus PCOS post-treatment hsCRP 0.52 +/- 0.26, P = 0.005; PCOS pretreatment sVCAM-1 668.09 +/- 98.38 versus PCOS post-treatment sVCAM-1 365.82 +/- 99.77, P = 0.039. CONCLUSION: These findings imply the presence of chronic inflammation in women with PCOS. Metformin decreases the levels of plasma inflammatory indices. Further investigation is required to determine whether these findings may prove to be of clinical significance for PCOS patients.     

Comparative Study for Preventive Effects of Intra-Abdominal Adhesion Using Cyclo-Oxygenase-2 Enzyme (COX-2) Inhibitor,Low Molecular Weight Heparin (LMWH), and Synthetic Barrier

Purpose

Postoperative adhesion is the most frequent complication of abdominal surgery. Therefore, we investigated the individual effects of synthetic barrier [hyaluronic acid/carboxymethylcellulose (HA/CMC)] and pharmacologic agents [low molecular weight heparin (LMWH) cyclo-oxygenase-2 inhibitor (COX-2 inhibitor)] using animal model of intra-abdominal adhesion.

Materials and Methods

The cecum was rubbed with sterile alcohol wet gauze until subserosal haemorrhage and punctate bleeding developed under the general anesthesia. Five animal groups were prepared using the film HA/CMC, gel HA/CMC, LMWH and COX-2 inhibitor.

Results

The grade of adhesion by modified Leach method for group I (control), II (film type HA/CMC), III (gel type HA/CMC), IV (LMWH) and V (COX-2 inhibitor) were 5.35±1.8, 6.15±1.3, 4.23±2.6, 5.05±0.7 and 5.50±0.9, respectively. Group III showed the least grade of adhesion and it is statistically significant in adhesion formation (p=0.028). The numbers of lymphocytes were significantly low in group III and group V compared to the control group (lymphocyte: p=0.004). The mast cell counts were generally low except for the control group (I: 1.05, II: 0.35, III: 0.38, IV: 0.20, V: 0.37), however, it was not statistically significant (p=0.066).

Conclusion

The gel barriers were shown to be partly efficient in inhibiting the formation of postoperative adhesions and might provide an option for abdominal surgery to reduce postoperative adhesions. The LMWH and COX-2 inhibitor had been known for their inhibitor effect of fibrin formation and anti-angiogenic/anti-fibroblastic activity, respectively. However, their preventive effects of adhesion and fibrosis were found to be obscure.     

The effect of prostaglandins and aspirin--an inhibitor of prostaglandin synthesis--on adhesion formation in rats

The effect of intraperitoneal application of prostaglandins E2 and F2 alpha and of aspirin, a non-steroidal anti-inflammatory drug, on the formation of intraperitoneal adhesions was investigated in rats, in view of the main role of the body's reaction in adhesion formation. Intraperitoneal adhesions were induced by inflicting uniform trauma to the uterine serosa. It was demonstrated that prostaglandin E2 may increase adhesion formation and that intraperitoneal aspirin is able to inhibit its formation.     

Hypoxaemia induced by CO(2) or helium pneumoperitoneum is a co-factor in adhesion formation in rabbits

A prospective randomized trial in a rabbit model was performed to test the hypothesis that the increase in adhesion formation following prolonged pneumoperitoneum is mediated by peritoneal hypoxaemia. Laparoscopic standardized opposing lesions were performed in uterine horns and pelvic sidewalls by bipolar coagulation and CO(2) laser in six groups of eight animals. Pure CO(2) or helium pneumoperitoneum was used for 10 (groups I and IV) or 45 min (groups II and V) to confirm the effect of duration of pneumoperitoneum and 96% of CO(2) or helium with 4% of oxygen (group III and VI) for 45 min to assess the effect of the addition of oxygen. After 7 days, adhesion formation was scored by laparoscopy. By two-way analysis of variance, total, extent, type and tenacity of adhesion scores increased (P = 0.0003, P = 0.0004, P = 0.0004 and P = 0.004) with increasing duration of pneumoperitoneum and decreased (P = 0.02, P = 0.03, P = 0.01 and P = 0.05) with the addition of oxygen. No differences were found between CO(2) and helium. In conclusion these data confirm the effect of pneumoperitoneum upon adhesions and demonstrate its reduction by oxygen, strongly suggesting that the main cause of adhesion formation is the relatively superficial hypoxaemia produced by the pneumoperitoneum.     

Reduction of post-surgical adhesions with ferric hyaluronate gel: a European study

BACKGROUND: The objective of this study was to assess the safety and efficacy of a 0.5% ferric hyaluronate gel, in reducing adhesions in patients undergoing peritoneal cavity surgery by laparotomy, with a planned 'second-look' laparoscopy. METHODS: The study was a randomized (by computer-generated schedule), third party blinded, placebo-controlled, parallel-group design conducted at five centres in Europe. Females aged 18-46 years received 300 ml ferric hyaluronate (n = 38) or lactated Ringer's (n = 39) as an intraperitoneal instillate at the completion of surgery. At second-look 6-12 weeks later, the presence of adhesions was evaluated at 24 abdominal sites. RESULTS: Patients treated with ferric hyaluronate had significantly fewer adhesions compared with controls. When adhesions formed, they were significantly less extensive and less severe in the treated group. The American Fertility Society score for adnexal adhesions was reduced by 69% in the treatment group compared with controls. The safety profile of ferric hyaluronate-treated patients was comparable with those treated with lactated Ringer's solution. CONCLUSIONS: In conclusion, ferric hyaluronate was safe and highly efficacious in reducing the number, severity and extent of adhesions throughout the abdomen following peritoneal cavity surgery.