Quantitative evaluation of intact peripheral nerve structures after utilization of CO2 laser, electrocautery, and scalpel

Objective: This study aimed to evaluate quantitatively the integrity of ner ve structures near CO2 laser incisions. Background Data: There are some hyp otheses that try to explain the analgesia reported after CO2 laser surgery. One of them is based upon the observation of the destruction of nerve endi ngs after use of this technique, Methods: A comparative study was carried o ut using 25 animals (Rattus norvegicus) divided into five groups of 5 anima ls each. Standard incisions were carried on the dorsum of the tongue of eac h animal using the cautery (group 2), scalpel (group 3), CW CO2 laser (grou p 4), and SPS CO2 (group 5); group 1 served as control. The animals were ki lled immediately after the experiment, and specimens were taken and routine ly processed to wax. Three-micrometer sections were cut and stained using S -100 protein antibody. The stained sections were analyzed under light micro scopy using a calibrated graticule, and the number of intact nerves was cou nted in five standard areas around the incision, Results: The results of th is study showed that there were no statistically significant differences in the numbers of intact peripheral nerve structures in both laser groups and other groups. No statistically significant difference was found between no noperated and scalpel groups. The number of intact peripheral structures in cautery wounds was significantly smaller than in nonoperated and scalpel w ounds. Conclusions: Therefore, it is unlikely that immediate destruction of peripheral nerve structures is the cause of post-operative analgesia follo wing CO2 laser surgery.