A practical grading scale for predicting outcome after radiosurgery for arteriovenous malformations: analysis of 1012 treated patients

Abstract

Object. The authors performed a study to review outcomes following Gamma Knife radiosurgery for cerebral arteriovenous malformations (AVMs) and to create a practical scale to predict long-term outcome.Methods. Outcomes were reviewed in 1012 patients who were followed up for more than 2 years. Favorable outcome was defined as AVM obliteration and no posttreatment hemorrhage or permanent, symptomatic, radiationinduced complication. Preradiosurgery patient and AVM characteristics predictive of outcome in multivariate analysis were weighted according to their odds ratios to create the Virginia Radiosurgery AVM Scale.Results. The mean follow-up time was 8 years (range 2-20 years). Arteriovenous malformation obliteration occurred in 69% of patients. Postradiosurgery hemorrhage occurred in 88 patients, for a yearly incidence of 1.14%. Radiation-induced changes occurred in 387 patients (38.2%), symptoms in 100 (9.9%), and permanent deficits in 21 (2.1%). Favorable outcome was achieved in 649 patients (64.1%). The Virginia Radiosurgery AVM Scale was created such that patients were assigned 1 point each for having an AVM volume of 2-4 cm 3 , eloquent AVM location, or a history of hemorrhage, and 2 points for having an AVM volume greater than 4 cm 3 . Eighty percent of patients who had a score of 0-1 points had a favorable outcome, as did 70% who had a score of 2 points and 45% who had a score of 3-4 points. The Virginia Radiosurgery AVM Scale was still predictive of outcome after controlling for predictive Gamma Knife radiosurgery treatment parameters, including peripheral dose and number of isocenters, in a multivariate analysis. The Spetzler-Martin grading scale and the Radiosurgery-Based Grading Scale predicted favorable outcome, but the Virginia Radiosurgery AVM Scale provided the best assessment.Conclusions. Gamma Knife radiosurgery can be used to achieve long-term AVM obliteration and neurological preservation in a predictable fashion based on patient and AVM characteristics.

WITHDRAWN: Predictors for complete obliteration of arteriovenous malformations following stereotactic radiosurgery

“…Moreover, deep AVM are reported to have lower obliteration rates after radiosurgery [10,[25][26][27]. Hattangadi-Gluth et al [10] reported an obliteration rate of 62% in AVM located in deep structures.…”

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

“…Patients with small AVMs (P=0.035) located in noneloquent brain regions (P=0.023) were more likely have a favorable outcome, which is consistent with previous AVM radiosurgery series. 9,15,16 With radiosurgery, the vast majority of complications associated with the treatment of ARUBA-eligible patients occurred within the first 2 years. Thereafter, the benefits of radiosurgery became more apparent over time, especially after the typical 3-year latency period after radiosurgery ( Figure 2B).…”

“…[14][15][16] The radiosurgery technique used at each institution has been previously described. 17 Briefly, a Leksell Model G stereotactic frame (Elekta AB, Stockholm, Sweden) was affixed to the calvarium after administration of local anesthesia.…”

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.…”

“…Complete obliteration, after a single session, has been reported to vary between 60% and 80% over 5 years. 1,2,4,5,7,21 Several metrics have been used to determine the appropriate prescribed dose during SRS for AVMs. One of the most widespread methods utilizes the K index, 14 first introduced in 1997 by Karrlson et al at the Karolinska Institute, Sweden.…”