Introduction: Optimal management of unruptured brain arteriovenous malformations (UBAVMs) remains controversial in the post-ARUBA era. ARUBA demonstrated superiority of medical management over combined interventional treatment after a mean follow-up of 33 months, with a 30.7% risk of stroke or death in the intervention group. Although microsurgery can offer immediate obliteration, it was represented in 14.9% of ARUBA’s intervention group only. The purpose of this study was to evaluate our institutional experience with microsurgery for UBAVMs over the past 20 years and to compare our results with ARUBA.
Methods: A retrospective chart review of the AVM database at Toronto Western Hospital was conducted from 1994 – 2014. UBAVMs treated with microsurgery alone or in combination with endovascular embolization or radiosurgery were identified. Patient demographic data, AVM characteristics (Location, Spetzler-Martin (SM) grading, size, eloquence, deep venous drainage, AVM-related aneurysms), and treatment outcomes (mRS, obliteration rates, neurologic deficits and adverse events) were recorded. Primary outcome measures were rates of early and permanent disabling outcomes (mRS=3), and secondary outcome measure was any permanent neurologic deficits (mRS=1). Outcomes were analyzed according to SM grades.
Results: Of 977 AVM patients identified, 155 patients had microsurgical resection for UBAVMs (71.6% with surgery only, 25.2% with pre-operative embolization) with a mean follow-up of 29.5 months. Complete obliteration was achieved in 94.2 % after initial surgery, and 98.1% on final angiography. Early and permanent disabling outcomes were present in 12.3% and 4.5% respectively, while any permanent neurologic deficit (mRS=1) occurred in 16.1%. Amongst UBAVMs of SM1&2, complete obliteration was achieved in 99.2%, with early and permanent disabling outcomes present in 9.3% and 3.4% respectively.
Conclusions: In our study, microsurgery for UBAVMs has lower rates of disabling neurologic deficits than in ARUBA, particularly for SM1&2. Treatment should be evaluated on an individual basis, accounting for AVM location, features of angio-architecture, and individual institutions’ experience.
Patient Care: ARUBA's conclusions need to be evaluated carefully. Microsurgery for unruptured brain AVM can achieve complete obliteration to eliminate lifelong hemorrhage risk, with lower risk of disabling stroke than had been reported in ARUBA.
Learning Objectives: 1. Discuss the risks of microsurgery for UBAVMs.
2. Evaluate the application of ARUBA results.