Can Brainstem Arteriovenous Malformations Be Safely Treated By Gamma Knife Surgery?Jui-To Wang1, David Hung-Chi Pan2, Wen-Yuh Chung1, Wan-Yuo Wayne GUO31Taipei Veterans General Hospital, Taipei, Taiwan 2Taipei, Taiwan 3Taipei Veterans General Hospital and Yang-Ming University Keywords: arteriovenous malformation, gamma knife, brain stem, outcome, radiosurgery
To investigate efficacy and safety of Gamma Knife Surgery (GKS) for the treatment of brainstem AVM.
Twenty patients with brainstem AVMs treated by GKS between 1993-2007 were enrolled for study. There were 7 men and 13 women with age ranged from 9-42 years. Fifteen patients received GKS once as the only and primary treatment, while another 5 patients underwent GKS twice to obtain a complete obliteration. Locations of AVMs included midbrain (15 cases), pons (7 cases) and medulla oblongata (2 cases).
AVM volumes ranged from 0.721-21.5 ml. The maximum dose to AVM nidi varied from 24-37 Gy with marginal dose ranged from 15-25 Gy. After radiosurgery, patients underwent regular MRI follow-up, a final angiogram was performed 2-4 years after GKS to verify complete obliteration (CO).
Eighteen patients (90%) had been followed for more than 24 months (median 37 months). Other two patients (10%) were followed less than 2 years. Varying degrees of AVM regression in MRI were observed in all patients. The angiographic follow-up after primary GKS in 15 patients revealed a CO rate of 67% (10/15). In five patients who failed to achieve CO after the first GKS, repeated treatment was performed. The second GKS resulted in CO of all 5 patients. Overall, the angiographic confirmed CO was obtained in 15 out of 20 cases (75%). Ten of 20 patients (50%) had no adverse radiation effect (ARE). Five patients (25%) had mild ARE without clinical manifestations. One patient (5%) with a large AVM involving midbrain and thalamus developed moderate ARE and complicated with motor weakness. Two patients (10%) had mild hemiparesis with rigidity due to late focal damage to cerebral peduncle. Two patients (10%) experienced mild brainstem hemorrhage after GKS, but recovered. There was no mortality in this study.
This is a retrospective study.
In this series, the cure rate of brainstem AVM was 75%, with treatment-related complications found in 3 patients (15%).
The complications were mild to moderate that daily activities were not much disturbed. We suggest GKS can be the treatment of choice for brainstem AVMs. Project Roles:
J. Wang (), D. Pan (), W. Chung (), W. GUO ()