Efficacy and Safety of the Electrospun Nanofibrous Adhesion Barrier for Laparoscopic Surgery in a Rabbit Model

PURPOSE: Most recently developed anti-adhesive membranes are not suitable for laparoscopic surgery due to weak mechanical properties or adhesive characteristics. To overcome these problems, we prepared electrospun bioabsorbable nanofibrous poly (lactic-co-glycolic acid)-based membranes as an adhesion barrier. We evaluated the efficacy and safety of this material for laparoscopic surgery in a rabbit model. METHODS: A standardized laparoscopic surgical trauma was made on the rabbit's uterine horn and adjacent abdominal wall to induce adhesion formation. The injured uterus was covered by a nanofibrous barrier or it was left untreated (the negative control group) (each group: n=14). To evaluate acute toxicity of this material, blood sampling was made 3 and 7 days after laparoscopic surgery to check liver and renal function. Three weeks after laparoscopy, a second look laparoscopy was performed and the adhesions were scored according to Blauer's scoring system. Tissue between abdominal wall and uterus was obtained to examine microscopically. Liver, kidney and uterus were harvested to examine chronic toxicity. RESULTS: 36.4% of the nanofiber treatment group and 70% of the untreated control group showed severe adhesions (grade>3) after laparoscopic surgery but failed to get a statistical significance (P=0.198). Acute and chronic toxicity induced by this material were not noted in the blood and tissue exam. CONCLUSION: This study showed that nanofiber barrier seems to be a novel resorbable biomaterial for the reduction of postoperative adhesions. Easy placement and handling of this material make these membranes potentially successful candidates for laparoscopic surgery. But further study is needed to get a statistical significance.

The Efficacy and Safety of HA/CMC Anti-adhesion Barrier Solution with Varying Viscosities

PURPOSE: Guardix-sol(TM) is solution type of anti-adhesion barrier, and it is composed of a mixture of hyaluronate (HA) and carboxymethylcellulose (CMC). The anti-adhesive effect was proved through several clinical trials with using this material, but the most efficient viscosity for this solution has not been shown by the previous research. The objective of this study was to evaluate the efficacy and safety of HA/CMC mixture solutions, with varying viscosities, in a rat model. METHODS: Three different viscosities (low=LV, mid=MV and high=HV) of the HA/CMC mixture solutions were prepared to evaluate their potential as a tissue adhesion barrier. The viscosity was measured by a Brookfield viscometer. To evaluate the anti-adhesion effect, a cecal-abdominal wall abrasion model was adopted. The denuded cecum was coated by a HA/CMC mixture of different viscosity or it was left uncoated (the negative control group) and then the denuded cecum was apposed to the abdominal wall (each group: n=10). All the rats underwent a second celiotomy after 14 days to evaluate the extent of their abdominal adhesions and tissue reactions (inflammatory response, granulation tissue formation and toxicity in organs). RESULTS: The viscosities of the HA/CMC mixture solutions were 248.+/-24.4 cps in the LV, 1,353.8+/-4.4 cps in the MV and 3,556.7+/-38.8 cps in the HV. The grade of adhesion and the adhesion area were significantly lower in the all HA/CMC mixture solution groups compared to the control regardless of their viscosity. The inflammatory responses were not remarkable at the application site and the major solid organs did not show histological change in the experimental groups. CONCLUSION: The difference of viscosity of HA/CMC mixture solutions did not affect the efficacy of the adhesion barrier. All the HA/CMC mixture solutions with varying viscosities showed a low inflammatory response and non-toxicity.

The Efficacy and Safety of HA/CMC Anti-adhesion Barrier Solution with Varying Viscosities

PURPOSE: Guardix-sol(TM) is solution type of anti-adhesion barrier, and it is composed of a mixture of hyaluronate (HA) and carboxymethylcellulose (CMC). The anti-adhesive effect was proved through several clinical trials with using this material, but the most efficient viscosity for this solution has not been shown by the previous research. The objective of this study was to evaluate the efficacy and safety of HA/CMC mixture solutions, with varying viscosities, in a rat model. METHODS: Three different viscosities (low=LV, mid=MV and high=HV) of the HA/CMC mixture solutions were prepared to evaluate their potential as a tissue adhesion barrier. The viscosity was measured by a Brookfield viscometer. To evaluate the anti-adhesion effect, a cecal-abdominal wall abrasion model was adopted. The denuded cecum was coated by a HA/CMC mixture of different viscosity or it was left uncoated (the negative control group) and then the denuded cecum was apposed to the abdominal wall (each group: n=10). All the rats underwent a second celiotomy after 14 days to evaluate the extent of their abdominal adhesions and tissue reactions (inflammatory response, granulation tissue formation and toxicity in organs). RESULTS: The viscosities of the HA/CMC mixture solutions were 248.+/-24.4 cps in the LV, 1,353.8+/-4.4 cps in the MV and 3,556.7+/-38.8 cps in the HV. The grade of adhesion and the adhesion area were significantly lower in the all HA/CMC mixture solution groups compared to the control regardless of their viscosity. The inflammatory responses were not remarkable at the application site and the major solid organs did not show histological change in the experimental groups. CONCLUSION: The difference of viscosity of HA/CMC mixture solutions did not affect the efficacy of the adhesion barrier. All the HA/CMC mixture solutions with varying viscosities showed a low inflammatory response and non-toxicity.

Anti-adhesive Effect of Poloxamer/Alginate/CaCl2 Mixture in the Rat Model

PURPOSE: The occurrence of post-surgical adhesion is still a major cause of postoperative morbidity due to the lack of satisfactory treatment or prophylaxis. Several adhesion barriers have been developed in the form of solutions or membrane in an attempt to solve these problems. However both types of tissue barriers have some limitations in their practical applications. In order to overcome these problems, a temperature-sensitive Poloxamer/Alginate/CaCl2 mixture was prepared as an adhesion barrier. With this material, toxicity, inflammation and the adhesion prevention effect was evaluated in an animal model. METHODS: The sol-gel transition behavior was measured using a viscometer. An in vitro gel stability test and an in vivo degradation test was performed. The anti-adhesion effect was evaluated using a cecal-abdominal wall abrasion model. The denuded cecum was coated with Poloxamer/ Alginate/CaCl2 mixture, GUARDIX-SL (positive control group) or neither (negative control group) and apposed to the abdominal wall (each n=14). One week after surgery, the level of adhesion was graded from zero to three using a whole-number system. RESULTS: The LCST of the poloxamer/sodium alginate mixture was 25 degrees C. The gel stability of Poloxamer was improved by adding mild cross-linked sodium Alginate/CaCl2 mixture. The adhesion grade and area were significantly lower in the experimental group than in the control. CONCLUSION: The anti-adhesive effect of the Poloxamer/Alginate/CaCl2 mixture was comparable to the previously- developed solution type barrier and all the materials had degraded within 21 days. From these results, Poloxamer/ Alginate/CaCl2 mixture is a good candidate for use as a coatable or injectable tissue adhesion barrier.