Comparative study between meshes of polyester with collagen and polytetrafluoroethylene in the repair of defects produced in abdominal wall of rats

Effects of nitrofurazone on correction of abdominal wall defect treated with polypropylene mesh involved by fibrous tissue

PURPOSE

To evaluate the effects of nitrofurazone on the correction of abdominal wall defect treated with polypropylene mesh involved by fibrous tissue in rats.

METHODS

A defect in the abdominal wall was created and corrected with polypropylene mesh in 20 rats. They were randomly distributed into four groups: control, fibrous mesh, nitrofurazone and nitrofurazone dip in the mesh. Euthanasia was performed in 21 post-operative days. The healing process was analyzed regarding the meshes and macroscopic and microscopic aspects.

RESULTS

All animals had adhesions. However, no statistically significant difference (p>0.05) when compared between groups. Similarly microscopic analysis, in which there was no statistical significance level for the evaluated parameters such as mono and polymorphonuclear lymphocytes, granuloma, fibrosis, necrosis and collagen proliferation.

CONCLUSION

There was no significant effect on the abdominal wall defect repair with polypropylene mesh surrounded by fibrous tissue when dipped in nitrofurazone 2%.

Critical analysis of experimental model for study of adhesions after incisional hernias induced in rats' and repair of abdominal wall with different biomaterials

BACKGROUND

Adhesions induced by biomaterials experimentally implanted in the abdominal cavity are basically studied by primary repair of different abdominal wall defects or by the correction of incisional hernias previously performed with no precise definition of the most appropriate model.

AIM

To describe the adhesions which occur after the development of incisional hernias, before the prosthesis implantation, in an experimental model to study the changes induced by different meshes.

METHODS

Incisional hernias were performed in 10 rats with hernia orifices of standardized dimensions, obtained by the median incision of the abdominal wall and eversion of the defect edges. Ten days after the procedure adhesions of abdominal structures were found when hernias were repaired with different meshes.

RESULTS

The results showed hernia sac well defined in all rats ten days after the initial procedure. Adhesions of the greater omentum occurred in five animals of which two also showed adhesions of small bowel loops besides the omentum, and another two showed liver adhesions as well as the greater omentum, numbers with statistical significance by Student's t test (p<0.05).

CONCLUSION

Although it reproduces the real clinical situation, the choice of experimental model of incisional hernia repair previously induced implies important adhesions, with possible repercussions in the evaluation of the second operation, when different implants of synthetic materials are used.

Effect of copaiba oil on correction of abdominal wall defect treated with the use of polypropylene/polyglecaprone mesh

PURPOSE

To evaluate the effects of copaiba oil on the correction of abdominal defect treated with the use of polypropylene/polyglecaprone mesh in rats.

METHODS

A defect in the abdominal wall was created and corrected with polypropylene/polyglecaprone mesh in 36 rats. They were randomly distributed into three groups: control, copaiba by oral administration (gavage) and copaiba oil dip in the mesh. Euthanasia was performed after seven, 14 and 21 post-operative days. The healing process was analyzed regarding the meshes and macroscopic and microscopic aspects.

RESULTS

All animals had abdominal adhesions, which were smaller in the copaiba (gavage) group (p<0.05). In microscopy, all animals had an acute inflammation stage and the inflammatory response was best characterized by foreign body-type granulomas around the mesh fragments, which was not found in the mesh fragments within the copaiba dip group. There was a greater area of necrosis and fibrosis in the copaiba dip group compared to the control group (p<0.05). The copaiba (gavage) group had a greater quantity of collagen fibers compared to the control group.

CONCLUSION

Copaiba oil administered by gavage decreased the amount of abdominal adhesions, besides accelerating the process of collagen fibers formation, without damages within the early stages of healing. However, when used by dip directly on the mesh, it had corrosive effects compromising the healing process of the abdominal wall.