Cavernous angiomas of the brain stem - Intra-axial anatomical pitfalls andsurgical strategies

BACKGROUND We review the surgical anatomy of the brain stem in relation to the surgical approaches adopted for treatment of cavernomas and identify po ssible "safe entry zones" on the anterior face of the brainstem. METHODS Twelve symptomatic patients with cavernoma or telangectasia of the brain stem were surgically treated. The brain stem was divided into the fol lowing anatomical areas: ventral medulla, dorsal medulla, dorsal pens, vent ral pens, ventral mesencephalon, and dorsal mesencephalon, so that the surg ical approach could be "individualized" according to the position of the ca vernoma, the nerve fasciculi and nuclei. RESULTS On the anterior surface of the brain stem a medullar paramedian obl ique access to the anterolateral sulcus and a paramedian sagittal pens acce ss seem to avoid the main nerve fasciculi and nuclei. CONCLUSIONS Although the parenchymal window produced by the cavernoma is th e most important parameter for the choice of approach, fairly safe entry zo nes may be identified even on the anterior surface of the medulla and pens. (C) 1999 by Elsevier Science Inc.