Microvascular surgery has rapidly _developed inn the last 30 years and vessels of 1.0 mm can be anastomosed easily with a patency rate over 90 percent and is widely used in clinical practice with remarkable success. To obtain more successful micro vascular anastomosis in smaller vessels, the improvement in methods of micro anastomosis, the development of micro vascular instruments including the operating microscope along with micro sutures, and anticoagulants are needed. These improvements made micro vascular anastomoses of vessels that are less than 0.5mm in external diameter possible. Huang et a1.3´ performed anastomoses of the vessels in rats with an external diameter of 0.2 mm using a high magnification operating microscope, specially designed micro instruments, and fine sutures, and achieved a patency rate of 76 percent in the second postoperative week. However, we tried to anastomose vessels with an external diameter of 0.25 mm with ordinary instruments and 11-0 nylon.
Animal studies on 180 rats were carried out by doing end-to-end anastomoses and 180 endto-side anastomoses. In the end-to-end and end-to-side anastomoses, each 180 rats were then divided into 3 groups each. Group A was the control group. Aspirin and persantin were given orally in group B. Ticlopidine hydrochloride was given orally in group C. The method of endto-end anastomosis was as follows : A superficial epigastric artery as small as 0.25 mm in diameter was severed transversely and longitudinal incisions, the length of the arterial diameter, were made down opposite sides of each end. Each flared fragment of the proximal end is approximated with each distal end and sutured together by only two stitches. The method of end to-side anastomosis was as follows. In the side of the femoral artery an elliptical hole was made the same length of the circumference of the superficial epigastric artery, then the superficial
epigastric artery was incised in the same manner as the end-to-end anastomosis. The flared ends of the superficial epigastric artery were then inserted into the hole of the femoral artery and sutured by four stitches.
Light microscopic and scanning electron microscopic observation was performed serially at 3 days, 2 weeks, 3 weeks after the microvascular anastomosis for studying change of vessel diameter and histopathological changes at the microvascular anastomotic sites.
The results were as follows
1. The patency rate for the end-to-end anastomoses in the third postoperative week was 2 5 % in the control group(A), 3 5 % in the aspirin-persantin group(B), and 40 % in the ticlopidine group(C) ; in the end-to-side anastomoses, 45 % in group A, 50 % in group B, and 60 % in group C.
2. In the patency rate, the ticlopidine group is slightly higher than the aspirin-persantin group and even higher than the control group (P ( 0.05) in the end-to-end and end-to-side anastomoses. However, the end-to side group is higher in all 3 groups than the end-to-end one (P ( 0.1).
3. The intimal regeneration in all arteries was completed at end of the third postoperative week in the end-to-end and end-to-side anastomoses.
4. Changes of the internal diameter in anastomosed vessels showed luminal narrowing in the vessels at the third postoperative day and still narrowing at the second and third postoperative week in the end-to-end anastomoses. However, initial postoperative widening continued into the third postoperative week in the end-to-side anastomoses.
The authors got a high success rate of anastomoses of very small arteries approximately 0.25 mm in external diameter, by developing a method of using an ordinary microscope and instruments, 11-0 nylon suture, and the administration of ticlopidine hydrochloride which is a more powerful anticoagulant than aspirin-persatin.
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