[Microsurgical extirpation of extra-pial angiomas of the pons].

Some arteriovenous malformations that are apparently located in the pons are in reality located on its surface. Thus, their extrapial dissection is possible. This is carried out under the surgical microscope and by means of the microtechnique. To nine available descriptions, the results obtained in four of our own patients are added: Three angiomas were in an extrapial antero-lateral position, one angioma reaching into the cerebellar hemisphere and causing a cerebellar haematoma. The fourth angioma was in the Brachium pontis and reached to the Flocculus and Loculus quadrangularis inferior. The patients (2 females, 2 males) were subjected to a subtemporal-transtentorial operation, the brachium-pontis angioma was operated on occipitally. Complete restoration was reached after the operation and the former activites were taken up again. The diagnosis was based on series angiography and computer tomography. The afferent vessels stemmed from one or several cerebellar vessels. The removal of the angioma requires the most subtile preparation.