Rectal prolapse is a socially disabling condition afflicting both the young and old individuals. Among the most used surgical procedures are the rectopexies with polypropylene meshes. To compare the biological behavior of two polypropylene, macroporous and monofilament meshes, of different pore size and manufactured with different structural configurations, when fixed on the pre-sacral fascia. Prolene® mesh, a woven mesh with pore size of 164 x 96µ; and T mesh, a non-woven experimental test mesh, with pore size of 4 x 3 mm and pore area 762 times larger than that of Prolene®. Eighteen mongrel dogs, weighing between 8 and 15 kg, were divided in two groups: Prolene® mesh (n=9) and T mesh (n=9). A 4,5 x 2 cm patch of mesh was used to perform the pre-sacral rectopexy by placing nonabsorbable sutures. On the 30th post-operative day, the animals were re-operated and a fragment of the rectal wall including its mesh patch was removed. The macroscopic study evaluated the presence of seroma, hematoma, abscess, fistula, stricture, adhesions and the degree of incorporation of the mesh. The microscopic analysis estimated the inflammatory reaction, foreign body reaction, fibroblastic penetration and the collagen densitometry. One dog of the Prolene® mesh group developed seroma and the mesh was not incorporated. Adhesions were present in all dogs. The other macroscopic parameters were absent in both groups. The microscopic analysis showed lesser inflammatory reaction and higher migration of fibroblasts, attesting the favorable incorporation of the prosthesis. Low foreign body reaction was present, implying satisfactory biological acceptation of the prosthetic material. The densitometry of collagen revealed that the T mesh, with pore area 762 x larger than that of the Prolene® mesh, incorporated a greater amount of total collagen. Whereas the amount of type III or immature collagen was similar in both meshes, the type I or mature collagen was greater in T mesh group. There was no difference between the two groups in macroscopic and histologic studies. Both meshes presented successful incorporation and good biological acceptation. There was a significantly greater incorporation of total collagen and type I (mature) collagen in the T mesh.
Wound healing; Collagen; Mesh; Rectal prolapse
