Intra-parenchymal tumor biopsy using neuroendoscopy with navigation

Neuroendoscopy has allowed us to biopsy tumors located in the ventricle and the para-ventricle. With this technique we can obtain specimens under direct visual monitoring and examine tumor dissemination. For intra-parenchymal tumors, however, we normally use stereotactic procedures to collect tissues or perform open biopsies. We now report that we have successfully combined neuroendoscopy with navigational guidance to biopsy intra-parenchymal tumors. We explain our methods and discuss the advantages and disadvantages of this technique.

We carried out intra-parenchymal tumor biopsies or resection using neuroendoscopy and guided navigation in three patients. We advanced a transparent sheath, containing a removable inner tube on which a navigation tool was mounted, to target tissues. We directly monitored procedures with a neuroendoscope placed in the transparent sheath. We collected specimens just in front of and in the tumor by forceps. In one patient with bleeding, we used the aspirator tip as a monopolar coagulator. We were also able to check for bleeding along the sheath tract using endoscopy. Without causing any new neurological deficits, we collected tissues for histological diagnosis of astrocytoma in two patients and radiation necrosis in one.

We believe that combining neuroendoscopy with navigation guidance is a safe and precise method for obtaining biopsies of intra-parenchymal tumors. Tumors with rich vasculature will not benefit from this procedure until better hemocoagulation instruments have been developed.