Lasers in Surgery and Medicine 5357-365 (1985) zy Microvascular Anastomosis Using the Milliwatt C02 Laser Matthew R. Quigley, MD, Julian E. Bailes, MD, Hau C. Kwaan, MD, Leonard J. Cerullo, MD, J. Thomas Brown, MD, Clara Lastre, and Dean Monma zyxwvut Division of Neurosurgery (M.R.Q., J.E.B., L.J.C., J.TB., D.M.), and the Department of Medicine (H.C. K.), Northwestern University Medical School and the Hematology/Oncology Section of the zyxwvuts VA Lakeside Medical Center (H.C. K., C. L.), Chicago. zyxw The milliwatt zyxwvuts CO2 laser was used to anastomose small vessels in a rat femoral artery model. The technique requires multiple brief applications of 60-70 mW after placement of three equidistant 10-0 nylon stay sutures. The vessel histology is described immediately and 1, 3, 7, and 21 days after the procedure. The laser effects tissue bonding through changes in the collagen of the adventitia and media. Subsequent healing consists of new collagen deposition in the adventitia and re- endothelialization of the intima associated with neointimal proliferation at 3 weeks. Key words: microvascular anastomosis, milliwatt COz laser, vascular injury, platelets, collagen INTRODUCTION Recent reports indicate the feasibility of performing microvascular anastomoses utilizing either the Nd-YAG or C02 laser. As the biophysical properties of the C02 laser produce limited heat propagation, its use might be favored in small vessel procedures. To date, there exists no published data documenting the chronology of histologic changes associated with C02-laser-assisted vascular anastomosis (LAVA). The present paper describes our technique of LAVA using the C 0 2 laser in arteries and the histologic observations following the procedure. MATERIALS AND METHODS Adult Sprague-Dawley rats (both sexes) weighing zyx 300-500 g were operated upon using intraperitoneal pentobarbitol (50 mg/kg) anesthesia. Groin incisions al- Address reprint requests to Dr. Hau C. Kwaan, V.A. Lakeside Hospital, 333 East Huron Street, Chicago, IL60611. Accepted for publication January 24, 1985 zyxwvu 0 1985 zyxwvut Alan R. Liss, Inc.