Comparative observations on effects of carbon dioxide laser-induced peripheral nerve lesions in the rat.

This study was conducted to determine any changes that might occur in the associated cell bodies and proximal nerve stumps of sciatic nerves cut with carbon dioxide laser radiation. These changes were then compared with the changes that occur when performed with cutting cautery and scalpel. Both the proximal stump and the related dorsal root ganglia were examined with light and electron microscopy. The sciatic nerve was severed in 10 rats with the carbon dioxide laser, a cutting cautery, or a scalpel. Subsequent histopathologic examinations revealed: (a) both myelin and axonal degeneration in scalpel cuts; (b) less degeneration of proximal stump myelin in laser cuts compared with cautery cuts; and (c) no abnormalities in the associated dorsal root ganglia of nerves cut with the carbon dioxide laser. It was concluded that both the carbon dioxide laser and cutting cautery result in less damage and degeneration than a scalpel when used to sever peripheral nerves. The difference between the laser and cautery lesions was more quantitative than qualitative in that both impart thermal energy to the nerve. The carbon dioxide laser resulted in the least amount of injury.