A Comparative Study of the Tissue-destroying Effect of the Laser and Electrocoagulation

Summary

The effect of the laser on compact, glandular tissue at the dosage employed for the local palliative treatment of tumors, can largely be mimicked with the aid of high-frequency current (HF-current), applied with the aid of an electro-hydro-thermo-probe: The experiments described in the present study were performed on the livers of 70 male Wistar rats. The laser was applied for 2 seconds at an output of 80 J at a distance to the tissue of 0.5 cm. In the first stage, in the acute experiment, the effect of the HF-current was matched to that of the laser by varying the modulated and unmodulated current components. It was found that the depths of penetration into the tissue at the given laser settings could be achieved with modulated HF-current (so-called coagulation current) at an output of more than 72 watts (equipment setting K 10), coagulation being performed for 10 seconds. The admixture of modulated HF-current (so-called cutting current) reduces the depth of penetration into the tissue. In the first 5 days, the depth of penetration increases after both laser irradiation and HF-coagulation, by a factor of 2 to 3. With respect to the depths of penetration (DP), the scatter ranges, and the histological changes, no difference is to be seen between laser and HF lesions: Laser DP = 5.7 mm (confidence range: 4.4 - 7.0 mm); HF DP (equipment setting K 10) = 4.8 mm (confidence range: 3.6 - 5.4 mm). After 5 days, even the lesions produced with unmodulated HF-current at a lower output (65 watts or 56 watts) no longer differ significantly from the laser lesions: HF DP (equipment setting K 9) = 3.9 mm (confidence range: 3.1-5.4 mm), and HF DP (equipment setting 8) = 4.1 mm (confidence range: 2.4-4.7 mm). The results after 15 and 25 days of healing then revealed decreasing depths of penetration as a result of reparative processes; with respect to the reference laser/HF coagulations, the results after this time were, however, analogous with those seen at 5 days. Thus, for palliative tumor destruction, high-frequency current would appear just as suitable as the far more expensive laser beam.

Key words:

Palliative tumor destruction - EHT-coagulation - Laser versus electrocoagulation