Microsurgical treatment of deep arteriovenous malformations--basal ganglia and thalamus

Surgery for deep nuclei arteriovenous malformations (AVMs) is controversial after the introduction of stereotactic irradiation and embolization. However, rupture of an AVM in this location can lead to catastrophic parenchymal or intraventricular hemorrhage. Thus, microsurgery still has its place in treatment of such lesions to prevent the untreated AVM bleeding or rebleeding. We present a series of 16 AVMs located in the deep nuclei treated by direct microsurgery before radiosurgery was available in 1993.

We reviewed the clinical and angiographic characteristic of 16 patients with deep-seated AVMs (three in caudate nucleus, three in lentiform nucleus and ten in thalamus). The surgical approach was described separately depending upon the location of the AVMs. The surgical outcomes were classified as excellent (symptoms improved), good (no additional neurological deficit), fair (minor neurological deficit), bad (major neurological deficit) and dead.

Complete AVM elimination was achieved in 16 patients (100%) in one-stage operation. Eleven patients had excellent or good outcomes, three had fair outcomes and two had bad outcomes. There were no deaths in this series. Two patients had permanent hemiparesis to make a late morbidity rate of 12.5%.

With improving microsurgical techniques, neuroimaging and neuroanesthesia, difficult and deeply hidden AVMs can be successfully resected under microsurgery with an acceptably low morbidity and mortality rate.