THE RELATIONSHIP OF DIFFERENT POWER SETTINGS AND FIBER GEOMETRIES TO THERMAL TISSUE-DAMAGE CREATED BY THE SUPERPULSE ND-YAG LASER

We attempted to quantify the amount of thermal damage that was created to surrounding tissues when an incision was made with the superpulse neodymium:yytrium-aluminum-garnet (Nd:YAG) laser with the optical fibe r in contact. Light micrographic studies of several incisions, at diff erent laser power settings and with different fiber geometries, were m ade in the anterior abdominal wall of 16 Sprague-Dawley rats. The spec imens were collected immediately postoperatively and at 48 hours posto peratively. Several laser power settings (2-50 W) and seven different optical fiber geometries were studied. The micrographs showed minimal damage (< 0.1 mm) to surrounding tissues at all laser power settings i n both the immediate and the 48-hour studies. The superpulse Nd:YAG la ser with optical fiber contact limited laser thermal damage to the sur rounding tissues to less than 0.1 mm in the range of power settings st udied. Higher power settings minimally increased the damage. The geome tries of the optical fiber created no significant alteration in therma l damage. The results suggest that the superpulse Nd:YAG laser creates both thermal and photodisruptive effects in tissue.