Draining Vein Shielding in Intracranial Arteriovenous Malformations During Gamma-Knife

Abstract

Following gamma knife (GK) therapy for intracranial arteriovenous malformations (AVMs), obliteration of the nidus occurs over several years. During this period, complications like rebleeding have been attributed to early draining vein occlusion. To evaluate if shielding the draining vein(s) during GK therapy prevents early draining vein obliteration and complications following GK therapy. This was a nonrandomized case-control study over 5 years (January 2009-February 2014) and included patients with intracranial AVM who underwent GK therapy at our center. All patients who underwent draining vein shielding by the senior author (D.A.) were included in the test group, and patients who did not undergo draining vein shielding were put in the control group. Patients were followed up for at least 6 months (and every 6 months thereafter) clinically as well as radiologically with computed tomography head scans/magnetic resonance imaging brain scans to check for postradiosurgery imaging (PRI) changes. One hundred eighty-five patients were included in this study, of which 96 were in the control group and 89 were in the test group. Both groups were well matched in demographics, comorbidities, adjuvant treatment, angioarchitecture, and radiation dosing. Because of shielding, the test group patients received significantly less radiation to the draining vein than the control group (P = .001). On follow-up, a significantly lower number of patients in the test group had new neurological deficits (P = .001), intracranial hemorrhage (P = .03), and PRI changes (P = .002). Shielding of the draining vein is a potent new strategy in minimizing PRI and hemorrhage as well as clinical deterioration following GK therapy for intracranial AVMs.