[Technic of the peroperative use of Doppler in neurosurgery]

Intraoperative Doppler exploration during neurosurgery was used during treatment of intracranial aneurysms, arteriovenous malformations (AVM) and cerebral revascularization by extra-intra cranial anastomosis (EICA). It was also employed to study behavior of cortical arteries under different conditions. During treatment of aneurysms, Doppler can show, prior to clipping, whether blood flow through. The flow is regular--spasm of supply artery provokes acceleration of blood rate. After clipping it is possible to evaluate whether artery is still permeable without stenosis or torsion. In AVM, Doppler detects direction of blood. Flow and, in case of intraoperative embolization, confirms good exclusion of angiomatous nidus. Flow rate in cortical arteries was determined to verify reality of operative trauma under automatic retractors used in standard surgery. In EICA, Doppler provides precise data on exact localization of cutaneous incision centered on superficial temporal artery (STA) (longitudinal incision) and identifies its parietal branch. The artery in the cortical vessels with the lowest flow rate can be selected. After EICA it is possible to identify whether the donor artery is under spasm from the proximal clamp and whether or not the anastomosis is patent. When functioning is correct it can be defined whether there exists a preferential direction or a regular laminar distribution in T. In tumoral pathology, Doppler serves to identify arteries enclosed in lesion and therefore whether conservation is essential.