Introduction: Frameless neuronavigation has shown to be a useful adjunct during a variety of neurosurgical procedures. Despite being the gold standard for the imaging of intracranial vasculature, catheter-based angiography is not commonly used as the source for neuronavigation when treating lesions such as arteriovenous malformations.
Methods: A stereotactic end-to-end verification phantom patient (STEEV, CIRS Inc, Norfolk, VA) was used. The data sets obtained after scanning the phantom head on the 3D mode of the angiography equipment (Allura FD 20, Philips, Andover, Massachusetts) and on conventional CT scan were merged in the neuronavigation platform (BrainLAB iPlan Cranial 3.0.3, BrainLAB AG, Germany). The accuracy was measured by targeting structures on the 3D Rotational Angiography and aligning to those targets with the Brainlab Varioguide Frameless Biopsy system. Deviation from the planned target was measured using a dataset obtained from a mobile intraoperative CT (Airo, BrainLAB AG, Germany). Several landmarks were targeted and the difference in millimeters was recorded. Two surgically resected AVMs and one AVM treated with frameless stereotactic radiosurgery had great visualization of the AVM and accuracy in relation to conventional imaging.
Results: Using three targets in the phantom patient, the difference between the merged studies and the mobile intraoperative CT was non-significant (0.6mm, 1.5mm and 1.6mm, respectively) (Figure 1). Three patients with arteriovenous malformations have been treated successfully using this technique to navigate during surgical resection or during treatment with frameless stereotactic radiosurgery (Table 1).
Conclusions: Use of catheter based angiography during frameless neuronavigation is feasible, accurate and effective adjunct during the treatment of cerebral arteriovenous malformations. The same protocol could be used during frameless radiosurgery.
Patient Care: Having the best imaging for AVMs, cerebral angiography, merged with conventional imaging provides a safer alternative when performing surgical resection or frameless stereotactic radiosurgery.
Learning Objectives: By the conclusion of this session, participants should be able to:
Recognize the feasibility and accuracy of merging 3D rotational angiography with conventional imaging (CTA, MRI) during frameless neuronavigation and stereotactic radiosurgery during the treatment of arteriovenous malformations.