In vivo evaluation of a collagenous membrane as an absorbable adhesion barrier Glenn A. Edwards, 1 Veronica Glattauer, 2 Timothy J. Nash, 3 Jacinta F. White, 2 Kathy A. Brock, 1 Jerome A. Werkmeister, 2 and John A. M. Ramshaw 2, * 1 School of Veterinary Science, University of Melbourne, Werribee, Victoria 3030; 2 CSIRO, Division of Biomolecular Engineering, Parkville, Victoria 3052, and 3 Cyanamid Australia, 5 Gibbon Road, Baulkham Hills, New South Wales 2153, Australia An absorbable membrane made from purified, pepsin- showing fewer, less extensive adhesions. The collagen mem- soluble collagen was compared to Interceed TM , an absorbable branes resulted in either no or weak adhesions between the cellulose-based product, and to a control group for effective- body wall and caecum. Adhesions in the Interceed TM group ness in inhibiting the formation of adhesions between perito- were quite variable and characterized by a marked peritoneal neal surface injuries in adult rats. An adhesion scoring system reaction in the caecal and body walls adjacent to adhesions. was used to evaluate and compare the performance of the Control samples were characterized by close, dense fibrotic test materials with the control group in regard to the extent, adhesions between the caecum and body wall. Both of the tenacity, and type of any adhesions evident at 28 days follow- test materials showed some deficienies in respect to their ing surgery. The collagen group performed significantly bet- physical and handling properties that could be further im- ter ( p  0.05) than either the Interceed TM or control groups, proved for this indication.  1997 John Wiley & Sons, Inc. INTRODUCTION derivatives, 8,9 and the regenerated cellulose product, Interceed TM . 10,11 In the present study, a collagen-based membrane Adhesion barriers are intended to reduce the forma- has been compared to Interceed TM and a control group tion of postsurgical adhesions in patients undergoing for effectiveness in inhibiting the formation of adhe- pelvic surgery, especially for gynecologic problems, sions between peritoneal surface injuries created in the and for cardiovascular procedures such as coronary caecum and an adjacent, corresponding-size area of artery bypass surgery and heart valve replacement, to injured abdominal wall in adult rats. Since collagen prevent adhesion of the heart and grafts to the sternum. is the principal protein component of all connective A variety of materials have been proposed for this tissues, it has long been seen as having the potential purpose (see References 1–3), although only one, Inter- to be a valuable biomaterial. 12 Medical devices made ceed TM (Johnson & Johnson Patient Care, Inc.) is from collagen come in two distinct forms. In one, the commercially available for clinical use, and is used native structure and architecture of a collagenous tis- in patients undergoing pelvic surgery. Expanded poly- sue is retained and the material adapted for use in tetrafluoroethylene membrane (Gore-Tex TM ; W. L. a specific indication. 13 This approach has been used Gore and Associates) is among the synthetic materials effectively, for example, in porcine bioprosthetic heart which have been examined, 4 but this material suffers valves where the functionality of the original tissue from the disadvantage that is not resorbable. Most architecture is maintained and the device is made dura- proposed materials, however, are resorbable as this is ble through stabilization by glutaraldehyde crosslink- seen as a desirable feature. For example, a synthetic ing. 14 Previously, a tissue-based collagen material, un- hydrogel has been proposed that can be photopolymer- treated amnionic membrane, was examined and found ized in situ, and which performed well in various in to be unsuitable for prevention of adhesions. 6 In an- vivo models. 3 A wide range of natural materials have other study, however, where the amnion membrane also been examined, all of which are resorbable. These was radiation treated, more satisfactory results were include collagen-based materials, 5–7 hyaluronan and obtained. 7 The alternative approach for making collagen-based devices is to prepare soluble collagen, purify it, and then reconstitute it into a material which *To whom correspondence should be addressed. Journal of Biomedical Materials Research, Vol. 34, 291–297 (1997)  1997 John Wiley & Sons, Inc. CCC 0021-9304/97/030291-07