EFFECT OF OPTICAL-TEMPERATURE FEEDBACK-CONTROL ON PATENCY IN LASER-SOLDERED MICROVASCULAR ANASTOMOSIS

Feedback control has been postulated to improve the efficacy of laser welding in microsurgery, but alteration of outcome has not been clearl y shown. The authors evaluated the ability of an optical closed loop t emperature feedback control to improve patency, aneurysm rate, and to histologically limit thermal damage. Rat femoral artery anastomoses we re performed under operating microscope magnification. One hundred and twenty-four anastomoses were performed in five groups using 1) free-h and (FH) 1.9-mu m laser soldering without feedback; 2) temperature con trolled (TC) 1.9-mu m laser soldering with optical feedback; 3) FH 808 nm laser, 4) TC 808 nm laser soldering; and 5) 10-0 nylon suture cont rol. In Groups 2 and 4, an optical feedback system controlling laser e xposure to produce a preset temperature was used. Anastomotic time was significantly less for all laser groups (p < 0.05). Late patency for all 1.9-mu m laser anastomoses was almost 0. Temperature controlled 80 8-nm anastomoses showed no significant difference From sutures in term s of patency (88 percent vs. 96 percent), bursting pressure, and aneur ysm rate, while freehand 808-nm anastomoses had a significantly lower patency (71 percent) and more tissue damage (ANOVA, p < 0.05). The aut hors conclude that temperature control improves outcome in microvascul ar anastomosis by reducing transmural,thermal injury caused by variati ons in surgeon technique.