Severity Of Adhesion Formation Research Articles

Development of melatonin-embedded PLGA-PEG6000 nanofiber biomaterial, and investigation of the effects on abdominal adhesion formation

Abdominal adhesions are still among the most common postsurgical peritoneal inflammation-related complications. Adhesion-related disorders are still highly costly and prevalent due to advances in surgical techniques, treatment methods, and various drugs. The present study aimed to investigate the effects of Poly ( D,L-lactide-co-glycolide) (PLGA)- polyethylene glycol (PEG6000) Nanofiber + Melatonin on the abdominal adhesion model in rats. For this purpose, PLGA-PEG6000 Nanofiber + Melatonin matrix was fabricated and implanted in an experimental abdominal adhesion model in rats. Our study consisted of an in vitro and an in vivo part. The degradation and release profile of the matrix and Melatonin (Mel) embedded matrix was performed in vitro. In vivo, the procedure was carried out with 18 Wistar male rats. Rats were divided into three groups as follows: Sham, Matrix, and Mel + Matrix, respectively. Consequent to degradation and release profiling in vitro, an experimental adhesion model was created and fabricated pure matrix (2 × 2 cm2), and matrix (2 × 2 cm2, 0.25 mg melatonin/per matrix embedded) was applied to injury area in related groups. Intra-abdominal adhesion scores were determined on post-op 21st day, under general anesthesia. Following, cecum, peritoneal tissue, and adhesive bands were harvested. Macroscopic analysis (severity of adhesion formation), Hematoxlyn&Eosin and Masson’s Trichrome staining (for the examination of the levels of infiltration of inflammatory cells, fibrosis, and neovascularization) were performed for the evaluation of the effects of Mel embedded and pure matrix Our results indicated that PLGA-PEG6000 Nanofiber + Melatonin matrix was degraded completely in rats abdominal cavity and significantly reduced adhesion formation compared to other groups macroscopically ( p < 0.05). On the other hand, the histopathological analysis indicated that the fabricated matrix reduced inflammatory cell infiltration, fibrosis, and neovascularization levels.

Increasing the level of cytoskeletal protein Flightless I reduces adhesion formation in a murine digital flexor tendon model

BackgroundSurgical repair of tendons is common, but function is often limited due to the formation of flexor tendon adhesions which reduce the mobility and use of the affected digit and hand. The severity of adhesion formation is dependent on numerous cellular processes many of which involve the actin cytoskeleton. Flightless I (Flii) is a highly conserved cytoskeletal protein, which has previously been identified as a potential target for improved healing of tendon injuries. Using human in vitro cell studies in conjunction with a murine model of partial laceration of the digital flexor tendon, we investigated the effect of modulating Flii levels on tenocyte function and formation of adhesions.MethodsHuman tenocyte proliferation and migration was determined using WST-1 and scratch wound assays following Flii knockdown by siRNA in vitro. Additionally, mice with normal and increased levels of Flii were subjected to a partial laceration of the digital flexor tendon in conjunction with a full tenotomy to immobilise the paw. Resulting adhesions were assessed using histology and immunohistochemistry for collagen I, III, TGF-β1and -β3ResultsFlii knockdown significantly reduced human tenocyte proliferation and migration in vitro. Increasing the expression of Flii significantly reduced digital tendon adhesion formation in vivo which was confirmed through significantly smaller adhesion scores based on collagen fibre orientation, thickness, proximity to other fibres and crimping. Reduced adhesion formation was accompanied with significantly decreased deposition of type I collagen and increased expression of TGF-β1 in vivo.ConclusionsThese findings suggest that increasing the level of Flii in an injured tendon may be beneficial for decreasing tendon adhesion formation.

Intraperitoneal Adhesions After Open or Laparoscopic Abdominal Procedure: An Experimental Study in the Rat

Adhesion formation is common after abdominal surgery. The incidence and severity of adhesion formation following open or laparoscopic surgery remain controversial. The role of CO(2) pneumoperitoneum is also widely discussed. This study aimed to compare adhesion formation following peritoneal injury by electrocoagulation performed through open or laparoscopic procedures in a rat model. Sixty male rats were randomized to undergo a 1.5-cm peritoneal injury with unipolar cautery under general anesthesia: open surgery (Group A, n=20), laparoscopic surgery with CO(2) pneumoperitoneum (Group B, n=20), and laparoscopic surgery with air pneumoperitoneum (Group C, n=20). Duration of the procedures was fixed at 90 minutes in all groups, and pneumoperitoneum pressure was kept at 10 mm Hg. Ten days later, the animals underwent a secondary laparotomy to score peritoneal adhesions using qualitative and quantitative parameters. Forty-five rats developed at least one adhesion: 95% in Group A, 83% in Group B, and 55% in Group C (P<.01; Group C versus Group A, P<.01). According to number, thickness, tenacity, vascularization, extent, type, and grading according to the Zühkle classification, no significant difference was observed between Groups A and B. The distribution of adhesions after open surgery was significantly different than after laparoscopic surgery (P<.001). It is interesting that Group C rats developed significantly fewer adhesions at the traumatized site, and their adhesions had less severe qualitative scores compared with those after open surgery (P<.01). In this animal model, CO(2) laparoscopic surgery did not decrease the formation of postoperative adhesion, compared with open surgery. The difference with the animals operated on with air pneumoperitoneum emphasizes the role of CO(2) in peritoneal injury leading to adhesion formation.

A Novel Hydrogel-Coated Polyester Mesh Prevents Postsurgical Adhesions in a Rat Model

The specific aim of this study was to determine the whether a novel, hydrogel-coated polyester mesh (Scout) can be used to reduce the incidence and severity of adhesion formation in vivo. An established rat model of post-surgical adhesion formation was used in which adhesions are generated through surgical trauma to the surfaces of the cecum and the adjacent abdominal wall. Thirty-seven rats were randomly allocated either to a control group (no intervention; n=14 rats) or to one of two treatment groups in which the abraded surfaces were separated with either the Scout material (n=11 rats) or an FDA-approved form of expanded polytetrafluorethylene (PTFE) (PRECLUDE Vessel Guard; n=12 rats). Animals were euthanized 7 d after surgery and gross necropsy examinations were performed. Mechanical testing was used to measure the strength of any adhesions that were identified, and histology was used to characterize within the adhesion tissue and on the surface(s) of the barrier materials. Five animals were excluded because of surgical failure (1 control; 2 PRECLUDE Vessel Guard; 2 Scout). Adhesions were seen in 10 of 13 control animals (77%). There were no adhesions in any of the animals treated with either PRECLUDE Vessel Guard or Scout material. Histology demonstrated mild cellular adhesion to both the PRECLUDE Vessel Guard and the Scout material. Although there was a sub-acute to chronic inflammatory response to the surgical trauma, there was no evidence of delamination, shearing, or degradation of either the Scout material or PRECLUDE Vessel Guard. The hydrogel-coated Scout material was as effective as the approved predicate material in this model. Both materials were well tolerated. Further testing of the Scout material is now warranted.

Postoperative Adhesion Formation After Peritoneoscopy with Liver Biopsy in a Survival Porcine Model: Laparotomic vs Laparoscopic vs NOTES® Transgastric Approach

Background: Adhesions are an almost inevitable consequence of laparotomy and laparoscopy, although laparoscopic surgery produces fewer adhesions than laparotomy. It is suggested that minimizing the invasiveness of the operative technique by using NOTES™ may reduce adhesion formation. Objective: The aim of the study was to compare the rate of the adhesion formation after peritoneoscopy with liver biopsy by laparotomy, laparoscopy and transgastric NOTES™. DESIGN: Experimental comparative survival study. Setting: Research facility of the Johns Hopkins University School of Medicine. Patients: 18 female pigs that weighed 35-40 kg were used. Interventions and Methods: Peritoneoscopy with liver biopsy was randomized to 1 of 3 groups: control, laparotomy (n=6); laparoscopy (n=6), NOTES™ transgastric (n=6). Pre-operative, operative, and post-operative care was standardized. The Hopkins Adhesion Formation score method was used to assess adhesion formation. The following parameters were evaluated 1) extent - (the abdomen was divided into 4 quadrants - left upper quadrant, right upper quadrant, left lower quadrant and right lower quadrant; number of involved abdominal quadrants was documented); 2) frequency (number of bands); 3) size/width (total size/width of all adhesions was measured and summed total for every animal); 4) organ involvement (number of organs involved); 5) density of the adhesions; 6) dissectibility of the adhesions; and 7) vascularization. MAIN OUTCOME MEASUREMENTS: (1) Survival and complication rates (2) Necropsy (Day 14) (3) Assessment of adhesion formation rate using the Hopkins Adhesion Formation Score; (4) Differences between the groups by one-way analysis of variance (ANOVA) followed by a Tukey post-test analysis (5) Pearson product moment correlation coefficient (r-value) between the adhesion scores of two investigators. Results: There was no mortality in any study group. 100% of pigs in laparotomy group, 33.3% in laparoscopy group had adhesions compare to 16.7% in transgasric NOTES™ group. One adhesion band was documented in Group III (transgastric NOTES™), 4 adhesion bands in Group II (laparoscopy) and 17 in Group I (laparotomy). The mean adhesion formation scores of laparotomy and laparoscopy were 2.4 and 0.8 compared with 0.17 in the transgastric NOTES™ (P< 0.001). The Correlation coefficient between the adhesion scores of two investigators was r = 0.99 (p < 0.001, 95% CI). Limitations: Low number of study animals. Conclusions: Rate and severity of adhesion formation was lower in the transgastric NOTES™ group compared to laparoscopy and laparotomy, when peritoneoscopy with liver biopsy was performed.

Effect of n-Butyl-2-Cyanoacrylate on High-Risk Colonic Anastomoses

We investigated the effect of n-butyl-2-cyanoacrylate (BCA) on colonic anastomosis under clean contaminated procedure (CCP) and bacterial peritonitis (BP) conditions in rats. Male Wistar albino rats (n = 80) were divided into two groups: CCP and BP. In the CCP group, colonic resection and anastomosis were performed. BP was induced by cecal ligation and puncture. BCA was administered to the anastomosis in half of the rats in both groups. Anastomotic assessment was done on postoperative days 3 and 7 by evaluating the burst pressure, and gross anastomotic and histopathologic healing indices. The presence and severity of adhesion formation was also investigated. There were no differences in terms of gross healing parameters on days 3 and 7. Burst pressures were also similar on both days (p = 0.244 and p = 0.101, respectively). In the early phase (day 3), adhesion development (p < 0.001), granulocytic cell infiltration (p = 0.02), inflammation (p = 0.019) and necrosis (p = 0.019) were higher in the BCA groups. Mononuclear cell infiltration (p = 0.659), fibroblastic cell infiltration (p = 0.538) and capillary formation (p = 0.316) were similar. In the late phase (day 7), adhesion development (p < 0.001), necrosis (p = 0.001) and granulocytic cell infiltration (p = 0.034) were higher in the treatment groups. Fibroblastic cell infiltration (p = 0.017) and capillary formation (p = 0.016) were lower in BCA treated rats, particularly in the BP condition. Mononuclear cell infiltration did not differ (p = 0.176). The application of BCA did not provide any benefit under either CCP or BP conditions. Moreover, BCA caused increased inflammatory reactions, necrosis and adhesion formation. During the late phase of healing, the ongoing enhanced inflammation caused a reduction in capillary formation and fibroblastic infiltration, particularly under BP conditions.

Effects of Peritoneal Lavage with Scolicidal Agents on Survival and Adhesion Formation in Rats

Intraoperative irrigation of the peritoneal cavity with scolicidal agents is frequently recommended when dealing with traumatic or spontaneous rupture of hydatid cysts. The present experimental study was designed to examine the influence of various scolicidal agents on adhesion formation and survival. A total of 149 rats were randomly allocated to nine groups. Peritoneal lavage through a median laparotomy was performed with the following scolicidal agents. Group 1 (0.9% saline: controls), group 2 (20% hypertonic saline), group 3 (0.04% chlorhexidine gluconate), group 4 (3% hydrogen peroxide), group 5 (0.5% silver nitrate), group 6 (1% polyvinylpyrrolidone-iodine, or PVP-I ), group 7 (5% PVP-I), group 8 (0.5% cetrimide/0.05% chlorhexidine), and group 9 (10% PVP-I). The surviving animals were sacrificed on postoperative day 15. Adhesion formation was macroscopically graded by the Nair criteria. The severity of adhesion formation was evaluated microscopically using the fibrosing scoring criteria and the strain test. Group 9 (10% PVP-I) was excluded from the adhesion evaluation because all of the rats died in this group. The mortality rate was significantly higher in groups 5 and 7 than in groups 1, 2, 3, 4, 6, and 8. Adhesion scores were significantly lower in groups 1, 2, 3, and 4 than in groups 5, 6, 7, and 8. The lowest adhesion score was found in group 3 and the highest in the group 7. These results indicate that 0.04% chlorhexidine gluconate, the most potent scolicidal agent in vitro and in vivo, was associated with the lowest adhesion formation and mortality among various scolicidal agents in this experimental study.

Adhesion preventive effect of a novel hyaluronic acid gel film in rats.

This study evaluated the efficacy of a novel hyaluronic acid (HA) gel for preventing adhesions in a rat caecal model. The gel was manufactured from an acidic HA solution using a freezing procedure. HA gel films with four different half-lives (50-200 h) in physiological buffered saline at 37 degrees C were prepared, by regulating the freezing time, and tested. The HA gel film was applied as a barrier on the injured caecal surface after standardized treatment with a rotary abrasion apparatus. A control group of 20 animals were abraded in the same way but not treated. Seven days after the initial operation, the incidence and severity of any adhesions were recorded. Application of the HA gel film significantly reduced the incidence and severity of adhesion formation in all treatment groups compared with the control group. This novel HA gel film is effective for reducing post-operative adhesions in this rat model and the resorption rate is optimum for adhesion prevention on the caecal surface.

The effect of intra-abdominal pressure on the generation of 8-iso prostaglandin F2 during laparoscopy in rabbits

Carbon dioxide pneumoperitoneum induces peritoneal oxidative stress. The aim of this study was to verify the effect of intra-abdominal pressure on oxidative stress in the peritoneum and on post-operative adhesion formation. Forty-one rabbits underwent laparoscopic surgery: either gasless, or with CO(2)-pneumoperitoneum at pressures of 5, 10 or 15 mmHg. Serial parietal peritoneal biopsies were taken at various time-points: immediately after reaching the abdominal cavity, 30, 60, 90 and 120 min afterwards, and 15 min after abdominal desufflation. 8-iso prostaglandin F(2alpha) (8-iso PGF(2alpha)), a marker of oxidative stresss, was assayed by enzyme immunoassay and adhesion formation was scored by second-look laparoscopy on day 14. The gasless group showed no significant changes in 8-iso PGF(2alpha). Conversely, significant changes occurred in CO(2)-pneumoperitoneum in a time- and pressure-dependent manner. Adhesions developed only in the CO(2)-pneumoperitoneum groups, and total adhesion score was correlated with the amount of CO(2) insufflated and intra-abdominal pressure, but not with 8-iso PGF(2alpha), which was correlated with intra-abdominal pressure. Intra-abdominal pressure increased 8-iso PGF(2alpha) in the parietal peritoneum in a graded fashion, whilst gasless laparoscopy had no impact. It also influenced the frequency and severity of adhesion formation, but no causal link was found between 8-iso PGF(2alpha) and post-operative adhesion formation.

Incidence of postoperative adhesion formation after transperitoneal genitourinary laparoscopic surgery

Objectives. To evaluate adhesion formation after urologic laparoscopy, a multi-institutional review was conducted among adult patients who underwent a second procedure after an initial transperitoneal laparoscopic procedure. Adhesion formation after abdominal surgery remains a major cause of postoperative morbidity. Peritoneal adhesions result in hospitalizations and interventions that result in healthcare costs of more than 1 billion dollars annually. The risk of adhesion formation from transperitoneal genitourinary laparoscopy in adults has not been previously studied. Methods. Twenty-seven patients (mean age 45.5 years, range 24 to 71) were identified who underwent a second laparoscopic procedure after their initial urologic laparoscopic procedure was performed. The mean time between the procedures was 11.4 months (range 8 days to 38 months). At the time of the repeated laparoscopy or open surgery, the peritoneal cavity was examined and mapped for type (grade), extent (length), and location of any adhesions at the operative and trocar sites. The adhesions were graded as 0, no adhesions; 1, flimsy; 2, dense; and 3, cohesive. The extent was graded as 0, no adhesions; 1, less than 2 cm; 2, 2.1 to 10 cm; 3, greater than 10.1 cm. Results. Overall, adhesions occurred in 6 (22.2%) of 27 patients. Operative site adhesions occurred in only 3 (8.2%) of 34 possible operative sites (gastric augmentation cystoplasty, renal cyst ablation, nephropexy). Trocar site adhesions occurred in 4 (3.5%) of 114 possible sites (two nephrectomies, one cyst decortication, and one orchiectomy). All adhesions were classified as grade 1 and extent 1, except for a single grade 2, extent 2 adhesion. In most patients, retroperitonealization occurred with minimal or no scarring noted. None of the patients developed symptoms as a result of the adhesion formation. Conclusions. Although intraperitoneal adhesions do occur with adult urologic laparoscopy, the incidence is low. Also, in the few patients who do form adhesions, they are flimsy and short. This evidence, when contrasted with the available data on adhesion formation after open surgery, suggests that transperitoneal laparoscopic approaches to genitourinary surgery may have advantages over traditional open transperitoneal approaches by lowering the incidence and severity of adhesion formation.

Costop in the prevention of adhesions

Adhesion formation is a significant source of postoperative morbidity. Current barrier products on the market in the United States are difficult to use during a laparoscopic procedure or over irregular surfaces. The efficacy of a sprayable adhesion prevention barrier, CoStop, was evaluated in three separate rabbit adhesion models. In an initial study, the effect of CoStop and Seprafilm bioresorbable membrane was evaluated in a rabbit uterine horn abrasion model. At necropsy, 67% of the CoStop-treated rabbits and 61% of the Seprafilm-treated animals were adhesion free. In a rabbit sidewall adhesion formation model, 90% of rabbits treated with CoStop were free of adhesions at necropsy, whereas all surgical controls formed adhesions. A comparable level of efficacy was observed in a rabbit re-formation model in which adhesions were generated and lysed 1 week later. After adhesiolysis, all control rabbits re-formed adhesions over 95% of the area. In contrast, 67% of the CoStop- and 38% of the Seprafilm-treated rabbits were adhesion free. Histological evaluation performed on tissues from the studies indicates that the CoStop barrier is biocompatible in all three surgical situations. CoStop-treated animals in all adhesion models showed a significant reduction in the incidence, extent, and severity of adhesion formation.

Prevention of Pericardial Adhesions with N-O Carboxymethylchitosan in the Rabbit Model

The presence of mediastinal adhesions significantly increases the morbidity and mortality of reoperative cardiac surgical procedures. Previous investigations have reported on the therapeutic utility of topical hydrogels in reducing the formation of postsurgical adhesions. The goal of the present study is to evaluate the ability of N-O carboxymethylchitosan (a glycosaminoglycan hydrogel derivative) to reduce the formation of postsurgical pericardial adhesions in a large-animal model. Sixteen adult New Zealand white rabbits were randomly assigned to one of two treatment groups. Group 1 subjects (n = 8) had N-O carboxymethylchitosan directly applied to the heart and retrosternal surfaces after sternotomy was performed, while subjects in group 2 (n = 8) had saline applied to these areas. After a period of 14 days the animals were sacrificed under anesthesia, and independent observers, blinded to treatment, graded the formation of pericardial adhesions. The severity of adhesion formation was significantly less in the group treated with N-O carboxymethylchitosan (p < .01). This study demonstrates that N-O carboxymethylchitosan markedly decreases the formation of poststernotomy adhesions in a large-animal model without untoward cardiac side effects. This hydrogel derivative may prove to be of great therapeutic value when used prophylactically in the setting of cardiac surgery.

Effects of increased in vivo excursion on digital range of motion and tendon strength following flexor tendon repair.

Postoperative rehabilitation is an important factor in determining functional outcome following intrasynovial flexor tendon repair. We hypothesized that a rehabilitation protocol that produced increased in vivo excursion would lead to increased digital range of motion and tendon strength and decreased adhesion formation in a canine model. Ninety-six flexor digitorum profundus tendons from 48 dogs were cut transversely and repaired by a multistrand suture technique. Postoperative rehabilitation was performed daily with a low excursion-low force (1.7-mm average excursion; < 10 N force) or a high excursion-low force (3.6 mm excursion; < 10 N force) protocol. After death of the dogs at 10, 21, or 42 days, specimens were evaluated for digital range of motion, tensile mechanical properties, elongation of the repair site, and adhesion formation. Our data indicate that the range of motion of digits whose tendons were at low or high excursion was similar to that of controls. Increased in vivo tendon excursion due to synergistic wrist motion did not significantly affect ex vivo flexion of the distal and proximal interphalangeal joints or tendon displacement (p > 0.05). Similarly, tensile properties (ultimate load, repair site rigidity, and repair site strain at 20 N and at failure) and length of the gap at the repair site were not significantly affected by increased excursion (p > 0.05). Severity of adhesion formation was reduced slightly by increased excursion (p = 0.04). Our findings indicate that 1.7 mm of tendon excursion is sufficient to prevent adhesion formation following sharp transection of the canine flexor tendon and that additional excursion provides little added benefit.

An experimental study of the effect of aprotinin on intestinal adhesion formation

background Depression of fibrinolysis is known to be a major mechanism for postoperative adhesion formation. Because aprotinin inhibits fibrinolysis it may lead to an increase in adhesion formation whereas its anti-inflammatory effects may lead to a decrease in adhesion formation. Our aim is to clarify conflicting results in previous literature. methods Basal levels of intestinal hydroxyproline (OHP) content and local fibrinolytic activity (LFA) were determined using naive groups. In the experiment groups, adhesions were created by scraping and creating a transient ischemia of a segment of terminal ileum. Group I and II rats were injected subcutaneous (sc) normal saline (NS) for 3 days and single dose intraperitoneal (ip) NS, respectively. Group III and IV rats were injected sc aprotinin for 3 days and single dose ip aprotinin, respectively. Group V rats were injected intramuscular methylprednisolone (MP) for 3 days. LFA and OHP levels were determined on the second and fifth postoperative days. The severity of adhesion formation was graded on the fifth day. results Aprotinin decreased both the severity of adhesions and OHP levels whereas MP decreased only the severity of adhesions. There was an early depression of LFA at the second day in both NS and MP groups increasing to basal levels at the fifth day. OHP levels showed significant correlation with adhesion severity. conclusion Results showed that aprotinin decreased intra-abdominal adhesion formation probably by preventing early depression of LFA.

Prevention of experimental postoperative peritoneal adhesions by N,O-carboxymethyl chitosan

Postsurgical adhesion formation can result in significant morbidity and, to a lesser extent, death. The purpose of this experiment was to assess the ability of N,O-carboxymethyl chitosan (NOCC) to prevent postsurgical adhesion formation in vivo. Randomized groups of Sprague-Dawley rats were studied under two abdominal surgery models, the uterine horn model and the small bowel laceration model, for the ability of NOCC to reduce the incidence and severity of adhesion formation. Adhesions in animals were assessed after death by a blinded observer 10 to 14 days after surgical manipulation. NOCC consistently reduced the size, strength, and number of adhesions in both rat models. NOCC was also found to be more effective than hyaluronic acid at inhibiting adhesion formation. NOCC is a more effective antiadhesion agent than is the more expensive hyaluronic acid. Although the exact mechanism of NOCC's antiadhesion activity is as yet unclear, the novel chemical is of particular interest for clinical use.

Comparison of Microsurgery and Cyanoacrylate for Tubal Anastomosis: An Experimental Study in the Rat

We compared the results of tubal anastomosis performed by a microsurgical technique and by the application of cyanoacrylate, a tissue adhesive agent. Forty Spraque-Dawley female rats were reared under identical conditions and divided into four groups of 10 rats each. In the first group, all the rats underwent a lower midline vertical incision followed by closure of the abdomen using 3-0 Vicryl. In the second group, anastomosis of the left uterine horn was performed by using cyanoacrylate. The right horn was anastomosed microsurgically with 8-0 Prolene sutures. In the third group, the uterine horn was anastomosed with cyanoacrylate, and the left horn was ligated. In the fourth group, the right horn was anastomosed by microsurgical technique, and the left horn was ligated. After mating, a repeat laparotomy was performed to evaluate the number of pregnancies, the presence and severity of adhesion formation, and histopathologic changes induced by both techniques. Although there was no difference between the two methods with respect to corpus luteum formation in the ovaries and the number of embryos, the number of pregnancies was higher when microsurgical techniques were used. The severity of adhesion formation was greater after cyanoacrylate application than after microsurgery, and this could be the reason for the higher pregnancy number in the microsurgery group. Cyanoacrylate application is a simple and time-saving procedure. Based on these findings in the rat, a prospective trial in the human would be warranted. This may be an alternative to microsurgery in tubal end-to-end anastomosis. (J GYNECOL SURG 12:261, 1996)

Efficacy of a resorbable hydrogel barrier, oxidized regenerated cellulose, and hyaluronic acid in the prevention of ovarian adhesions in a rabbit model

To compare the efficacy of a resorbable hydrogel material with oxidized regenerated cellulose and hyaluronic acid in an ovarian adhesion model. Controlled, blinded, and randomized study involving female rabbits. Academic research environment. A water-soluble hydrogen precursor was applied to the ovary as a liquid and converted to a hydrogel by exposure to long wavelength ultraviolet light, a 0.4% solution of hyaluronic acid was applied to the ovary, or an oxidized regenerated cellulose patch was applied to the ovary after wedge resectioning. Extent and severity of adhesion formation. Application of the hydrogel reduced adhesion formation by 88%. Neither oxidized regenerated cellulose nor hyaluronic acid reduced adhesion formation. The photopolymerized, resorbable hydrogel material is highly effective for the reduction of periovarian adhesions in this model.