The sequence of histological change induced by CO2 laser irradiation was discussed in terms of two factors: the physiomechanical factor and the physiochemical factor. At sufficiently high heat energy levels, the immediate findings are characterized by crater formation resulting from rapid vaporization of the water and ejection of the solid component. In the immediate vicinity of the crater edge, the maximum tissue temperature rise is 65 degrees C above the 32 degrees C ambient tissue temperature and it decreases to the primary tissue temperature within a distance of 2 mm. The healing process of CO2 laser induced lesions proceeds with minimal delay. The lymphatic and vascular channels are occluded in the marginal area of coagulation resulting in a marked hemostatic effect. This sealing effect increases the margin of safety in preventing possible dissemination of tumor cells. By selecting the appropriate power, time, and focus cone angle, precise destruction of preselected areas of tissue can be achieved with an extraordinary hemostatic effect without damaging the underlying tissue. These advantages are especially helpful in function-preserving surgery.

No abstract

The purpose of this paper is to investigate the immediate effects on soft tissue induced by CO2 laser irradiation. The tongue of mongrel dogs was used. The laser beam was applied to the tissue at a right angle. Macroscopic and light microscopic observations were made immediately after the irradiation. The results are as follows: 1) The immediate effects induced by CO2 laser irradiation are characterized by a crater formation resulting from rapid vaporization of the water component of the tissue. 2) The injury in the area adjacent to the crater results from thermal denaturation of the tissue proteins. The coagulated area is greater in the horizontal direction than in the vertical direction. This may be attributed to the difference in heat transfer which follows a Gaussian distribution of CO2 laser energy. 3) The lymphatic and vascular channels are occluded in the coagulated area resulting in a significant hemostatic effect. Besides the hemostatic effect, this is of a great benefit in excision of malignant neoplasms, because of scattering of the tumor cells can be avoided.

No abstract