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  • A multicenter retrospective study of frameless robotic radiosurgery for intracranial arteriovenous malformation

    Final Number:

    Eric K Oermann BS; Brian T. Collins MD; Deanna Mary Sasaki-Adams MD; Kevin M. McGrail MD; Vikram V. Nayar MD; David Morris; Matthew G. Ewend MD

    Study Design:
    Clinical Trial

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2012 Annual Meeting

    Introduction: CT-guided, frameless radiosurgery is an alternative treatment to traditional catheter-angiography targeted, frame-based methods for intracranial arteriovenous malformations (AVMs). Despite the widespread use of frameless radiosurgery for treating intracranial tumors, its use for treating AVM is not well described.

    Methods: Patients who completed a course of single fraction radiosurgery at The University of North Carolina or Georgetown University between 4/1/2005 – 4/1/2011 and received at least one follow-up imaging study were included. All patients received pre-treatment planning with CTA ± MRA and were treated on the CyberKnife (Accuray) radiosurgery system. Patients were evaluated for changes in clinical symptoms and radiographic changes evaluated with MRI/MRA and catheter-angiography.

    Results: Of 36 patients treated, 20 patients were eligible for the study with a median age of 45 years (range, 15-75). Median nidal volume was 14.1 cm3 (range, 0.1-49 mm3) with a range of Spetzler-Martin Grades (Table 1) and a median Flickinger-Pollock Score of 2.7 (range, 0.6-22.3). 12 patients had radiosurgery alone, 7 had radiosurgery + embolization, and 1 had surgery followed by radiosurgery. A median dose of 20 Gy (range, 15-23) was delivered to a median isodose line of 80% (range, 62-85%). At a median follow-up of 25 months (range, 7-42), 9 (45%) patients had complete closure with an average time to closure of 27 months (range, 8-39). 6 (30%) of the remaining patients had partial closure, and 5 (25%) patients had no changes. 9 (45%) patients reported improvement in neurological symptoms. 64% of patients with greater than 2 years of follow-up had complete obliteration. No acute treatment related toxicity and one post radiosurgery hemorrhage occurred.

    Conclusions: Frameless radiosurgery can be targeted with non-invasive MRI/MRA and CTA imaging. Despite the difficulty of treating AVM without catheter angiography, early results with frameless, CT-guided radiosurgery suggest that it can achieve similar results to frame-based methods at these time points.

    Patient Care: This research will improve patient care by advancing the use of a non-invasive neurosurgical treatment which has the ability to deliver excellent outcomes with decreased or equivalent morbidity to traditional techniques.

    Learning Objectives: By the conclusion of this session, participants should be able to: (1) describe the outcomes and complications of frameless radiosurgery for intracranial AVM and (2) understand the technique and planning of a frameless approach.


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