Stereotactic biopsy of brainstem lesions: 21 years experiences of a single center.

Stereotactic biopsies are procedures performed to obtain tumor tissue for diagnostic examinations. Cerebral lesions of unknown entities can safely be accessed and tissue can be examined, resulting in correct diagnosis and according treatment. Stereotactic procedures of lesions in highly eloquent regions such as the brainstem have been performed for more than two decades in our department. In this retrospective study we focus on results, approaches, modalities of anesthesia, and complications. We performed a retrospective analysis of our prospective database, including 26 patients who underwent stereotactic biopsy of the brainstem between April 1994 and June 2015. All of the patients underwent preoperative MRI. Riechert-Mundinger-frame was used before 2000, thereafter the Leksell stereotactic frame was used. After 2000 entry and target points were calculated by using BrainLab stereotactic system. We evaluated histopathological results as well as further treatment; additionally we compared complications of local versus general anesthesia and complications of a frontal versus a trans-cerebellar approach. Median age of all patients was 33 years, and median number of tissue samples taken was 12. In all patients a final histopathological diagnosis could be established. 5 patients underwent the procedure under local anesthesia, 21 patients in general anesthesia. In 19 patients a frontal approach was performed, while in 7 patients a trans-cerebellar approach was used. Complications occurred in five patients. Thereby no significant difference was found with regard to approach (frontal versus trans-cerebellar) or anesthesia (local versus general). Stereotactic biopsies even of lesions in the brainstem are a save way to obtain tumor tissue for final diagnosis, resulting in adequate treatment. Approach can be trans-cerebellar or frontal and procedure can be performed either under local or general anesthesia without significant differences concerning complication rate.