Thermal Changes at the End of Fiber Tip during 810 nm Endovenous Laser Treatment

Abstract

Purpose: The endovenous laser treatment (EVLT) of saphenous vein insufficiency has been found out as less-invasive procedure than that of conventional procedure. Postoperative surgical trauma is reduced, since it is possible to treat legs under local anesthesia in the EVLT. Furthermore, early ambulation becomes possible immediately after the treatment because of less postoperative pain. An excellent long-term result has been obtained by applying the EVLT method. In order to improve a technique, this study was performed to evaluate the thermal fluctuation around the EVLT fiber tip.

Methods: The close circulation circuit was made by using 10 mm silicon tube, and milk was circulated as a pseudo-material for blood. The optical fiber was inserted in this pseudo-blood vessel, and the 810 nm laser was generated. As the laser output has been changed with 5 W, 10 W, and 15 W, the temperature changes around the optical fiber were measured.

Result: Thermal changes of pseudo-blood during early laser delivery phase were up to 2˚C. None of thermal changing was observed after 10 seconds of laser energy delivery. After carbonization around laser fiber tip due to thermal degeneration of circulating protein, increased temperature change more than 20˚C, possibly higher at laser tip, was observed.

Conclusion: In EVLT, carbonization around laser tip takes major role in elevation of temperature around laser fiber. Optimal condition for the procedure should be determined with consideration of carbonization and its effect to temperature change.