Clinical experience with intracranial brain needle biopsy using frameless surgical navigation.

Interactive, image-guided frameless systems are currently used in many centers for navigation during open craniotomies. We report our experience in 34 cases of brain needle biopsy performed with a frameless stereotactic system based on an optical digitizer. Preoperative images were acquired after adhesive skin markers were placed on the patient's head. Biopsy planning was done on the computer monitor using triplanar and 3-dimensional reformatted images. All biopsies were performed under local anesthesia through a twist drill craniostomy. The biopsy guide consisted of a rigid canula stabilized by a self-retaining retractor arm attached to the reference arc placed around the patient's head in the operating room. The position of the probe tip and its ideal continuation were displayed on real-time reformatted images and compared with the previously obtained trajectory plan. The position of the probe was adjusted as necessary to align it accurately with the surgical trajectory calculated by the computer in angles and displayed on the computer images. Diagnostic tissue was obtained in all cases; the mean and standard deviation of the maximum longitudinal diameter of the lesions was 3.5 +/- 1.1 cm. All patients reported minimal discomfort during the procedure; there was no operative morbidity or mortality. Our experience suggests that interactive image-guided frameless stereotactic brain needle biopsy successfully provides diagnostic tissue.