[Intraoperative ultrasonography through a burr hole: clinical trial of ultrasound-guided stereotactic surgery].

Intraoperative ultrasound diagnosis through a burr-hole was performed in 59 cases using electronic sector-scanning transducers. The burr-hole was conically enlarged and the gap between the transducer tip and the dura mater was filled either with saline or sterile echojelly. The pathology was successfully imaged in 33 cases (56%), or 20 out of 28 cases (71%) using a 5 MHz transducer. Compared to transdural ultrasonography, the quality of image through a burr-hole was found less satisfactory. Six cases of biopsy and/or aspiration were successfully performed under ultrasonic guidance through a burr-hole. Two burr-holes were necessary in these stereotactic operations. A needle-guide apparatus and the guideline superimposed on the monitor CRT screen were advantageously utilized. In biopsy, both the tumor and the biopsy needle were visible on the same monitor CRT screen, and accurate biopsy was possible. In aspiration, the tip of the needle could always be kept inside the cyst or abscess cavity. Bleeding during these manipulations was easily detected on the real-time monitoring CRT screen, and if necessary, it could be immediately controlled. Our results suggest that the intraoperative ultrasonography through a burr-hole will make these operations safer and more accurate.