A contralateral, transfrontal, extraventricular approach to stereotactic brainstem biopsy procedures. Technical note.

The authors report on the technique and results of stereotactic biopsy for intrinsic lateral pontine and medial cerebellar lesions via a contralateral, transfrontal, extraventricular approach. Multiplanar stereotactic magnetic resonance imaging was used to plan an intraparenchymal approach, thus limiting the number of crossed pial surfaces to one and eliminating the need to cross ependymal surfaces. After the administration of a local anesthetic agent with light intravenous sedation, six patients harboring intrinsic lateral pontine lesions underwent biopsies via this intraparenchymal approach with 100% diagnostic yield and no operative morbidity. In comparison to the ipsilateral transfrontal approach, the contralateral approach laterally expands the infratentorial area accessible during biopsy to include the lateral pons and middle cerebellar peduncle. The contralateral, transfrontal, extraventricular approach is a useful, straightforward and safe alternative to the suboccipital transcerebellar and ipsilateral, transfrontal, transtentorial routes for reaching lesions of the lateral pons and middle cerebellar peduncle.