Stereotactic radiosurgery for arteriovenous malformations, Part 1: management of Spetzler-Martin Grade I and II arteriovenous malformations

Abstract

Object. The aim of this paper was to define the outcomes and risks of stereotactic radiosurgery (SRS) for Spetz ler-Martin Grade I and II arteriovenous malformations (AVMs).Methods. Between 1987 and, the authors performed Gamma Knife surgery in 996 patients with brain AVMs, including 217 patients with AVMs classified as SpetzlerMartin Grade I or II. The median maximum diameter and target volumes were 1.9 cm (range 0.5-3.8 cm) and 2.3 cm 3 (range 0.1-14.1 cm 3 ), respectively. The median margin dose was 22 Gy (range 15-27 Gy).Results. Arteriovenous malformation obliteration was confirmed by MR imaging in 148 patients and by angiography in 100 patients with a median follow-up of 64 months (range 6-247 months). The actuarial rates of total obliteration determined by angiography or MR imaging after 1 SRS procedure were 58%, 87%, 90%, and 93% at 3, 4, 5, and 10 years, respectively. The median time to complete MR imaging-determined obliteration was 30 months. Factors associated with higher AVM obliteration rates were smaller AVM target volume, smaller maximum diameter, and greater marginal dose. Thirteen patients (6%) suffered hemorrhages during the latency period, and 6 patients died. Cumulative rates of AVM hemorrhage 1, 2, 3, 5, and 10 years after SRS were 3.7%, 4.2%, 4.2%, 5.0%, and 6.1%, respectively. This corresponded to rates of annual bleeding risk of 3.7%, 0.3%, and 0.2% for Years 0-1, 1-5, and 5-10, respectively, after SRS. The presence of a coexisting aneurysm proximal to the AVM correlated with a significantly higher hemorrhage risk. Temporary symptomatic adverse radiation effects developed in 5 patients (2.3%) after SRS, and 2 patients (1%) developed delayed cysts.Conclusions. Stereotactic radiosurgery is a gradually effective and relatively safe option for patients with smaller volume Spetzler-Martin Grade I or II AVMs who decline initial resection. Hemorrhage after obliteration did not occur in this series. Patients remain at risk for a bleeding event during the latency interval until obliteration occurs. Patients with aneurysms and an AVM warrant more aggressive surgical or endovascular treatment to reduce the risk of a hemorrhage in the latency period after SRS.

WITHDRAWN: Predictors for complete obliteration of arteriovenous malformations following stereotactic radiosurgery

“…The factors considered in the grading system are size of nidus, the type of venous drainage (superficial vs deep) and the location of AVM in terms of eloquence. Obliteration rates reported following radiosurgery for SM grades I and II range between 80% and 93% [9,30]. The obliteration rates following radiosurgery for SM grades III ranged from 60% to 72% [22,23].…”

“…The primary goal of treatment for AVM is the complete obliteration of the AVM, so that the risk of hemorrhage is eliminated [9]. Thus, identifying of the factors associated with higher obliteration rates is important.…”

“…Once complete obliteration is identified on angiography, the overall risk of hemorrhage drops to 1% [9]. However, an interval period exists from the time of radiosurgery until complete obliteration is achieved, during which the risk of hemorrhage remains.…”

Radiosurgery for Cerebral Arteriovenous Malformations in A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA)-Eligible Patients

“…3,21 Furthermore, 66% of the treated patients in ARUBA had Spetzler-Martin grade I or II AVMs, for which resection can be strongly considered at experienced centers, and radiosurgery provides an excellent risk to benefit profile. [22][23][24][25] Radiosurgery is a minimally invasive modality for the treatment of AVMs, and it is especially favorable, relative to microsurgery, for small-to moderate-sized AVMs in eloquent or deep brain areas. [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] The results of many previous radiosurgery series are confounded by the inclusion of patients who were previously treated with surgical resection, embolization, and fractionated radiation therapy.…”

Stereotactic radiosurgery of intracranial arteriovenous malformations and the use of the K index in determining treatment dose

“…Stereotactic radiosurgery has gained popularity in recent years. 1,2,4,5,[7][8][9][10][11][12]21 Its effect on the obliteration of AVMs is gradual, with patients remaining at risk for hemorrhage during this latency period. Complete obliteration, after a single session, has been reported to vary between 60% and 80% over 5 years.…”