Stereotaxic biopsy for deep-seated brain tumors using "BioTac biopsy cannula"

Abstract

A stereotaxic biopsy was carried out in 6 cases of deep-seated brain tumors, utilizing a “BioTac biopsy cannula”(manufactured by the Progress Mankind Technology, Co., U.S.A.). The tumors were located in the basal ganglia (2 cases), lateral ventricle (2 cases), thalamus (1 case) and parietal subcortex (1 case). Sufficient amounts of tumor specimens were obtained in all the cases to establish the histological diagnosis. The histology was germinoma in 2 cases, glioblastoma in 2 cases, astrocytoma (grade 2) in 1 case and metastatic adenocarcinoma in 1 case. Neurological deterioration occurred after biopsy in the case with a metastatic brain tumor in the lateral ventricle that had already shown signs of increased intracranial pressure and disturbance of consciousness. In retrospect, stereotaxic biopsy should not be done in such a case, unless a decompressive procedure is performed at the same time or prior to biopsy. “BioTac biopsy cannula” is essentially a modification of the instruments originally designed by Backlund, or Coe, et al. The cannula is introduced into the target location with the inner stylet. After removal of the inner stylet, the inner spiral tip cannula is slowly turned to the depth of the tissue required for sampling. Then, the outer cannula is advanced to capture the spiral tip containing the tissue specimen and finally the entire cannula assembly is removed to retrieve the tissue sample. The advantage of using this instrument is its ability to obtain tissue specimens even from firm solid tumors without difficulty. It is believed that this cannula should be added to the surgical armamentaria of every modern neurosurgical service.