Results and expectations with image-integrated brainstem stereotactic biopsy.

BACKGROUND The histologic diagnosis of an intrinsic brainstem tumor remains problematic due to controversies in methods of biopsy. Despite the widespread use of biopsy techniques, stereotactic brain stem biopsy has received limited attention due to potential morbidity and limited sample size. METHODS To evaluate the safety and efficacy of brain stem stereotactic biopsy using a dedicated computed tomography (CT)-stereotactic operating room suite, we reviewed our outcomes in 40 consecutive patients over a 13-year interval. This study included patients with midbrain lesions (n = 20), pontine lesions (n = 18), and medullary lesions (n = 2). Midline lesions were approached via a coronal, transthalamic trajectory; lateral brain stem lesions usually were approached via a transcerebellar route. RESULTS A histologic diagnosis was achieved in 38 patients (95%). All patients had an immediate, intraoperative, postbiopsy CT scan to check for hemorrhage (none occurred). Morbidity was limited to one patient (2.5%) who developed a transient diplopia; there was no mortality. CONCLUSIONS Stereotactic biopsy for intrinsic brain stem lesions proved as safe and effective as biopsy in the supratentorial compartment. Using high-resolution stereotactic imaging, an appropriate intraparenchymal trajectory, limited sampling, and specific neuropathologic tests, stereotactic techniques within the brain stem were performed with low risk and high accuracy. Biopsy results facilitated specific management strategies for each patient.