Introduction:
Despite concerns of hemorrhage, patients with occipital brain arteriovenous malformations (AVMs) also bear significant risk of post-treatment visual disturbances. We aim to characterize the risk of hemorrhage and visual disturbance in patients with occipital AVMs through our experience and literature review.
Methods:
Retrospective review of occipital AVM patients seen in our institution from 1990-2015. Patient characteristics were compared in a multivariate regression using follow-up visual disturbance as the outcome to determine risk factors. We also systematically reviewed PubMed for English literature describing occipital AVMs with case reports excluded.
Results:
Ninety-seven patients were included. Mean age was 34.9+/-16.4 years, with 50.5% male. Thirty-one(32.0%) presented with hemorrhage, and 32(33.0%) with visual disturbance. Average AVM size was 4.0±2.5 cm. Twenty-five(25.8%) were conservatively managed, 13(13.4%) underwent surgery, and the rest by radiosurgery(52.6%) or embolization(8.2%), with obliteration rate of 37.5% in treated patients. During an average follow-up period of 5.4 years, 6 patients(6.7%) hemorrhaged with overall annual rate of 1.2%, and 0.0% in surgically treated patients. Thirty-seven(38.3%) patients experienced visual disturbances, nineteen(21.1%) had de-novo visual disturbance, with 14 being treated patients(n=72,19.4%). Multivariable analysis found visual disturbance at presentation(p=0.012) and microsurgery(p=0.047) to be significantly associated with follow-up visual disturbance. From the literature, 8 series with 423 patients were eligible for consideration. Mean age was 32.8 years(55.0% male), and clinical presentation was: hemorrhage(33.6%), headache(56.5%), and visual disturbances(38.9%). AVM size was 3.34cm. During an average follow-up of 4.3 years, obliteration rates were between 30 to 100%. All series noted worsening of visual disturbances after treatment, particularly with microsurgery.
Conclusions:
While hemorrhage control remains the primary goal of AVM treatment, visual preservation in occipital AVMs is also a major concern. Recommending microsurgery for patients should be individualized as it sustains the highest risk of visual field disturbance albeit having optimal hemorrhagic control.
Patient Care:
The current study encompasses the institutional experience and literature review of a highly eloquent subset of AVMs. We expect this abstract to raise awareness that despite generally optimal outcomes reported with surgical obliteration in the literature, microsurgery predisposes the highest risk of post-treatment visual disturbance and should be cautiously justified before considered. This awareness prevents irrational aggressiveness of treatment paradigm based on existing literature, and is the first step in developing an individualized treatment algorithm for occipital AVM patients.
Learning Objectives:
By the conclusion of this session, participants should be able to: 1) Understand that presenting visual disturbance is unlikely to resolve at follow-up 2) Understand that despite having optimal hemorrhagic control, microsurgery predisposes the highest risk of visual disturbance in occipital AVMs and should be cautiously considered 3) Have a general understanding of rate of post-treatment visual deficits and treatment strategy for these patients based on the literature review