[Physical and technical bases of tumor hemostasis with a CO2 laser in neurosurgery]

The particular thermal properties of CO2 laser make it an useful instrument for neurological surgery. Necrosis and carbonization zones, as well as its thermal diffusion in the nervous tissue are dramatically less important with a CO2-laser unit than with other lasers (Nd-Yag or Argon) and moreover with the electrical mono--or bipolar coagulator. That is why the authors chosed this instrumentation for achieving a good hemostasis. It was particularly useful during removal of intracranial tumors situated close to the functional structures of the basis of the brain and the brainstem. The authors present their experience with the french CO2-laser unit Ercelas 80 (Robert et Carrière Biomedical) that they have been using routinely since 1983 in 60 neurosurgical procedures. They present the technical standards necessary to perform such an hemostasis either with the hand-piece or using the micromanipulator. In all cases the output power must be much lower for hemostasis than for tumoral cutting or vaporization. Depending on the type of tumor, radiation power should vary from 2 to 10 watts if a linear emission is used, and from 10 to 30 watts in case of pulsed emission. On the other hand, CO2-laser beam must be unfocussed so as to avoid cutting the vessels less than 0.5 mm in diameter before coagulating them properly.