EVALUATION OF HUMAN COLLAGEN BIOMATERIALS IN THE HEALING OF COLONIC ANASTOMOSES IN DOGS

Objective: To investigate the ability of human collagen biomaterials t o secure colonic anastomoses in dogs and to evaluate the biocompatibil ity of anastomotic protection patches (APP). Design: Experimental open study. Setting: Experimental research centre, France. Material: 21 mo ngrel dogs randomised into three groups of 7 each. Intervention: Stand ard transverse colonic end-to-end anastomoses were secured with two-la yer oxidised collagen I + III sponge covered with thin crosslinked col lagen IV film (APP 1) glued around the suture (n = 7); two-layer oxidi sed collagen I + III sponge covered with thin non-crosslinked collagen I + III film patch (APP 2) (n = 7); or sealed by fibrin sealant (n = 7), which acted as a controls. Main outcome measures: Gross examinatio n, radiological control (barium enemas), and microscopic examination o n day 35 postoperatively. Results: Gross clinical and radiological exa minations on day 35 showed normal wound healing in all but one dog in which the anastomoses had occluded by day 16. There was significantly less stricturing with the APP 2 patch (p < 0.05 compared with the cont rols). Microscopic examination showed complete absorption of the APP 2 patches as well as quicker mucosal and extracellular matrix repair th an controls. The APP 1 patch gave the best healing of the muscular lay er but did not reduce anastomosis stricturing, and was not totally abs orbed. Conclusions: Collagen supporting devices do not alter healing o f the large bowel. Encircling patches do not increase the number of ad hesions or the rate of anastomotic stricturing and a thin fibrillar co llagen I + III dense layer may even improve it. The speed of absorptio n of the patch depends on the type of dense collagen film. These resul ts argue for a prospective clinical evaluation in humans.