Effects of 1.32-micron Nd-YAG laser on brain thermal and histological experimental data.
Considering that the 1.32-microns Nd-YAG laser should have physicothermal properties close to those of the CO2 laser, a series of experiments were conducted on rat cortex (N = 51). Three laser wavelengths were compared: CO2 laser (10.6 microns), 1.06-microns Nd-YAG, and 1.32-microns Nd-YAG lasers. For each shot, temperature measurements were recorded with an infrared thermographic videocamera. The digitized signals were figured as thermal profiles and temperature developments. Ninety-five shots were correctly studied and analyzed: CO2, N = 29; 1.06-microns Nd-YAG, N = 20; 1.32-microns Nd-YAG, N = 46. The histological lesions produced by these three lasers were compared on animals killed 24 hours (N = 20), 8 days (N = 20), and 30 days (N = 5) after the laser impacts. For equivalent densities of energy, the depth of cortical necrosis was comparable for the CO2 laser (200-250 microns) and the 1.32-microns Nd-YAG laser (210-260 microns) whatever the date of death; the 1.06-microns Nd-YAG laser shots were responsible for much more important damage (400-550 microns). Because of its important absorption in water and nervous tissue, the authors consider the 1.32-microns Nd-YAG laser most suitable for neurosurgery, particularly because it is conducted through optic fibers, and therefore is easy to handle during neurosurgical procedures.
Roux
F X
FX
Department of Neurosurgery, C.H. Sainte-Anne, Paris, France.
Mordon
S
S
Fallet-Bianco
C
C
Merienne
L
L
Devaux
B C
BC
Chodkiewicz
J P
JP
D000818:Animals; D001921:Brain / Q000473:pathology* / Q000528:radiation effects* / Q000601:surgery; D006358:Hot Temperature / Q000009:adverse effects; D007834:Lasers / Q000009:adverse effects*; D008297:Male; D009336:Necrosis; D051381:Rats; D011919:Rats, Inbred Strains