Introduction: Management decisions for brainstem arteriovenous malformations (AVMs) are complicated by balancing significant treatment challenges and compelling risk of associated morbidity/mortality following hemorrhage in untreated lesions. The present study seeks to compare outcomes of brainstem AVMs between radiosurgery and conservative management.
Methods: We performed a retrospective review of brainstem AVMs patients evaluated at our institution from 1990-2013. Patients missing baseline information or those lost to follow-up were excluded. Baseline clinical and angiographic characteristics and subsequent hemorrhagic risk were evaluated according to brainstem AVMs location and treatment modality.
Results: From our database of 685 AVMs patients, we identified 30 brainstem AVMs patients with complete data. Mean age at diagnosis was 41.6±20.3 years, with 53.3%(n=16) being male. Sixteen(53.3%) presented with hemorrhage. Spetzler-Martin grades were: grade 2(13.3%), grade 3(66.7%), grade 4(16.7%), and grade 5(3.3%). Brainstem locations were: midbrain(63.3%), pons(30.0%), and medulla(6.7%). Twelve patients (40.0%) were conservatively managed, and 18 AVMs were treated, among which sixteen(88.9%) underwent radiosurgery, one(5.6%) underwent surgery, and one(5.6%) underwent embolization only. Average follow-up period was 4.7±5.7 years, and 5 patients(16.7%) experienced recurrent hemorrhage, with 3 in radiosurgery group and 2 in conservative management group, translating to an annual recurrent hemorrhage risk of 3.7% and 4.8%, respectively. Lesion obliteration was achieved in 8 patients(26.7%). We compared patients(93.3%) between the two largest treatment groups (radiosurgery and conservative management). Baseline clinical and angiographic factors were similar. Obliteration(determined by DSA/MRA) was achieved in 43.8% of those treated with radiosurgery(p = 0.008). Despite similar baseline mRS, we observed more patients with improvement of mRS at last follow-up in the radiosurgery group compared to conservative management(p=0.004). Recurrent hemorrhage during follow-up did not differ between the two groups(p = 0.887).
Conclusions: Our results suggest that with cautious patient selection, radiosurgery may achieve obliteration and symptom relief in brainstem AVMs patients without increasing subsequent risk of hemorrhage.
Patient Care: Conventionally, brainstem AVMs was deemed inoperable and conservative management was the mainstay treatment for brainstem AVMs. However, with advancement of surgical and radiosurgical techniques and equipment, combined with contemporary multimodality strategy, increasing evidence have favored a more aggressive regimen to manage these patients with surgical resection or radiosurgery. Evidence from both surgical and radiosurgery series have demonstrated acceptable hemorrhagic control and outcome. However, the prognosis following intervention has not been explored in a comparative setting with conservatively managed patients. We performed this study to examine the risk of subsequent hemorrhage and functional outcomes between treated and conservatively managed patients.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Understand the baseline clinical and angiographic characteristics of brainstem AVMs.
2) Understand that brainstem AVM management needs to balance between significant treatment challenges and higher risk of hemorrhage in natural history
3) Understand that treatment, particularly radiosurgery, may be potentially used to provide symptom relief and AVM obliteration in a select group of high-risk patients.