Ultrasound-based navigation during intracranial burr hole procedures: Experience in a series of 100 cases

BACKGROUND To establish a rational basis for intraoperative ultrasound guidance in neu rosurgical procedures via a single burr hole approach based on the experien ce of one hundred cases. METHODS The single burr hole approach is carried out using a bayonet-shaped ultraso und transducer with a tip dimension of 8 x 8 mm. The ultrasound probe with a mounted puncture adapter fits a standard burr hole and allows real-time i maging of the ongoing surgical steps. RESULTS One hundred cases with five indications have been operated on so far: tappi ng of the ventricular system (46 patients), tapping of intracranial cysts ( 23 patients), biopsy of intracranial tumors (15 patients), evacuation of in tracranial abscesses (9 patients), and evacuation of intracerebral hematoma s (7 patients). Depending on their size, the ventricles could be clearly vi sualized in 34 of 46 patients. In the remaining patients the free margin of the fair served as orientation. Two ventricles could neither be visualized nor entered. Visualization and puncture of intracranial cysts were easy to achieve throughout, as was the case with abscesses. Tumor biopsy was unsuc cessful in two patients harboring lymphomas at distances of more than 50 mm from probe to target. Intracerebral hematomas were easily visualized but, due to the presence of clots, aspiration was impossible in two patients. On e patient with a giant glioblastoma died the day after the uneventful biops y due to increased cerebral edema. No other complications occurred. CONCLUSIONS The presented method of ultrasound-based neuronavigation is an easy-to-use, fast, and safe technique of real-time imaging for free-hand single burr ho le procedures. (C) 2000 by Elsevier Science Inc.