A new ultrasound-guided brain biopsy technique through a burr hole. Technical note.

There is a disadvantage in brain biopsy by ultrasonic guidance comparing it with the CT guided approach. It is the fact that the ultrasonic method requires a small craniotomy or multiple trephinations because the size of the transducer exceeds the diameter of the burr hole and the echographic information from the trocar which houses the biopsy forceps, becomes poor when the sound beams run nearly parallel with the site of its insertion. The authors devised a brain biopsy technique through only one burr hole under real time monitoring, using a small foot-print transducer, 12 mm in diameter, and a special trocar with engraved scales on its surface. We believe that this new biopsy technique surpasses the traditional CT directed and ultrasound-guided methods in many respects. A representation case biopsied by this technique is presented.