[Prostheto-prosthetic and aorto-prosthetic anastomosis using stents, threads, clips and staples. In vitro comparative study].

OBJECTIVE

--To evaluate mechanical strength of new potential systems of vascular prostheses anastomosis versus usual suture (4.0 yarn), --To advance objective quantified data in order to establish the specifications of a new quick and reliable mechanical anastomosis device for laparoscopic surgery.

MATERIAL AND METHODS

Two experimental studies were conducted in order to quantify the mechanical resistance of anastomoses between two Dacron vascular prostheses and anastomoses between one Dacron vascular prosthesis and one cadaver abdominal aorta segment. Existing materials, which have generally used for other types of surgery, were applied for these studies (clips, staples, stents). These systems of anastomosis were compared to usual suture, used as reference.

RESULTS

The mechanical strength of an anastomosis between two Dacron vascular prostheses performed with staples or the same number of stitches is of equivalent magnitude. Anastomoses made with clips or stent are ten to fifteen times weaker than those made with stitches. We did not succeed in performing an anastomosis with staples on cadaver aorta segments because aorta segments tear when staples are applied. In the experiments with a hand-sewn graft, the aorta always tor before the suture, without breakage of the suture.

CONCLUSION

From these in vitro trials, we can advance that a continuous suture is probably far too resistant in relation to the aorta own resistance. As we do not know accurately the physiologic strength applied to a vascular prosthesis in vivo, one acceptance criterion from a safety point of view for a new anastomosis system must be that its strength will be equal to the well-proven continuous suture (greater than 150 N) or to the aorta breaking point (between 100 and 160 N). From that point of view, anastomoses performed with clips or a stent are not convenient, unless special clips or stents can be developed for this application. The mechanical strength is of staples sufficient but their design has to be adapted to this particular type of anastomosis.