Cortical blood flow during craniotomy for aneurysms.

A previously described thermal diffusion flow probe was used to monitor cortical blood flow in over fifty craniotomies for treatment of aneurysms. Hypotension, retractor pressure, vascular manipulation, and temporary vessel occlusion can be seen to affect cortical blood flow. By monitoring cortical blood flow, anesthetic and surgical techniques may be altered to prevent ischemic complications. We have only limited experience with early operation and with craniotomy in the face of vasospasm. Monitoring cortical blood flow may eventually allow operations in these instances to be accomplished more safely.