BACKGROUND: Radiosurgery is widely used to treat deep eloquent arteriovenous malformations (AVMs).
OBJECTIVE: To evaluate how anatomic location, AVM size, and treatment parameters define outcome.
METHODS: Retrospective analysis of 356 thalamic/basal ganglia and 160 brainstem AVMs treated with gamma knife radiosurgery.
RESULTS: Median volume was 2 cm3 (range, 0.02-50) for supratentorial and 0.5 cm3 (range, 0.01-40) for brainstem AVMs; the marginal treatment doses were 17.5 to 25 Gy. After single treatment, obliteration was achieved in 65% of the brainstem, in 69% of the supratentorial, and 40% of the peritectal AVMs. Obliteration of lesions <4 cm3 was better in the brainstem (70%) and in the supratentorium (80%), but not in the peritectal region (40%). Complications were rare (6%–15%) and mild (≤modified Rankin scale [MRS] 2). Rebleed rate increased with size, but was not higher than before treatment. AVMs >4 cm3 in the brainstem were treated with unacceptable morbidity and low cure rate. Obliteration of large supratentorial AVMs was 65% to 47% with more complications ≥MRS3. Repeat radiosurgical treatment led to obliteration in 66% of the cases with minor morbidity.
CONCLUSION: Deep eloquent AVMs <4 cm3 can be treated safely and effectively with radiosurgery. Obliteration of peritectal AVMs is significantly lower after a single treatment. However, morbidity is low, and repeat treatment leads to good obliteration. Radiosurgical treatment >4 cm3 in the brainstem is not recommended. Supratentorial deep AVMs >8 cm3 can be treated with radiosurgery with higher risk and lower obliteration rate. However, these lesions are difficult to treat with other treatment modalities, and a 50% success rate makes radiosurgery a good alternative even in this challenging group.
ABBREVIATIONS: AVM, arteriovenous malformations
MRS, modified Rankin scale
*The National Centre for Stereotactic Radiosurgery, Royal Hallamshire Hospital, Sheffield, United Kingdom
‡National Institute of Neurosciences, Budapest, Hungary
§Department of Radiology, Royal Hallamshire Hospital, Sheffield, United Kingdom
Correspondence: Andras A. Kemeny, FRCS, MD, The National Centre for Stereotactic Radiosurgery, Royal Hallamshire Hospital, Glossop Road, Sheffield, S10 2JF, United Kingdom. E-mail: firstname.lastname@example.org
Received July 18, 2011
Accepted November 30, 2011