Stereotactic Radiosurgery for Brain Arteriovenous Malformations: Evaluation of Obliteration and Review of Associated Predictors
Introduction
Brain arteriovenous malformations (AVMs) occur at an incidence of 1.12-1.42 per 100,000 person-years.1 Steiner et al.2 reported the first successful obliteration of an AVM using radiosurgery in 1972. Radiosurgery technology has evolved significantly, and minimally invasive stereotactic radiosurgery (SRS) has become a standard of care in managing brain AVMs, especially those located in deep or eloquent regions that would present high surgical risks.3,4 High AVM obliteration rates have been reported with SRS,5, 6, 7 and multiple factors have been found to be associated with obliteration following SRS for brain AVMs. However, the reporting of these factors in the literature has been inconsistent and disorganized. This study analyzes our experience with linear accelerator (LINAC)–based SRS for brain AVMs, including treatment success, radiation side-effects, and factors associated with obliteration, and reviews the various reported predictors of AVM obliteration and compares to our patient population.
Section snippets
Patient Selection
The study protocol was approved by the Institutional Review Board. This retrospective study reviewed electronic medical records using our institution's EMERSE database8 to identify patients diagnosed with brain AVMs treated with SRS. International Classification of Diseases codes for brain AVMs in association with the Current Procedural Terminology code for SRS were used to identify the target population.8
We included all patients with brain AVMs confirmed with vascular imaging and treated with
Baseline Characteristics
One hundred forty-two AVMs in 128 patients treated with SRS were included. Mean patient age was 34.4 years (range 3-75). Forty-one treated AVMs (28.9%) were in patients ≤18 years old, and 73 AVMs (51.4%) were in males. Forty-three AVMs (30.3%) were treated before 2005. Seventy-four AVMs (52.1%) were associated with a hemorrhage before SRS, and 21 (14.8%) had been previously embolized without complete obliteration prior to SRS. The mean clinical follow-up time was 67.8 months (range 24-256), and
AVM Obliteration
AVM obliteration via LINAC-based radiosurgery was achieved in 80.3% in our series. Reported obliteration rates have varied widely (60-94%),5, 6, 7,9, 10, 11, 12, 13 partly because of differences between studies in the selected patient population, AVM characteristics and the method of determining AVM obliteration. Comparable to most series, Spetzler-Martin grades 3 and 2 were most frequently treated with SRS, with the majority of AVMs deemed to be in an eloquent location. Two early prominent
Conclusions
AVM obliteration with LINAC-based radiosurgery is safe and and is complete in approximately 80% of cases. Several factors associated with AVM obliteration have been identified but inconsistently reported due to inherent differences in study populations, as reviewed in the current study. The most prominent predictors of obliteration success include AVM size and volume, radiation dose, number of draining veins and patient age. Other factors to consider in assessing the efficacy of SRS include the
Declaration of Competing Interest
The authors report no conflict of interest.
Grant Support
None
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