AccuGyd: Accelerated Guidance for Accurate MRI-Guided Neurosurgery

Abstract: Advanced neurosurgery techniques are increasingly delivering life-changing therapies, and even cures, for a range of serious and life-threatening conditions. Neurosurgeons using minimally invasive surgery (MIS) techniques with MRI and CT guidance can ablate epileptic foci and place FDA-approved devices such as deep brain stimulators (DBS), all with sub-mm accuracy. Intraoperative imaging is guiding intraparenchymal administration of gene therapies in NIH trials of brain cancer and PD treatments. Cures for rare pediatric genetic diseases are on the cusp of using guided gene therapies. However, effective placement of these tiny devices and leads, as well as effective drug delivery, are held back by significant technical challenges. Neurosurgeons typically use MRI for pre-surgical planning and post-surgery validation. They clearly see it as enabling minimally invasive ablations for epilepsy or recurring tumors. But despite MRI’s transformative intraoperative abilities, it is seen as too complex and time-consuming by many neurosurgeons with already pressing surgical schedules. Leading neurosurgeons cite the lengthy workflow for catheter guidance within the scanner bore as a barrier to MRI-guided neurointerventions. The leading MRI trajectory guide requires multiple complex steps. Aligning the trajectory to hit a brain target requires multiple iterations of MRI acquisitions and device manipulations, requiring 6-14 highly trained personnel per procedure. The time to achieve alignment is quite variable, so the workflow is unpredictable. Our Phase I project demonstrated the innovation of a quantized, indexed device guide, which we term AccuGyd. The main innovation of AccuGyd is that by using a discrete indexing system, a brain location can be targeted with greater accuracy than is needed. This opens the door to design a much smaller and less complex device. AccuGyd requires only one MRI acquisition to determine its 3D orientation. Software uses that orientation and the desired brain target point to determine which of AccuGyd’s ~20,000 supported indexed trajectories is closest to the brain target point. Without further imaging, the software calculates which of several different cassettes, each with a guide shaft at a different angle, should be inserted into the AccuGyd base. The software outputs a second parameter, an indexed rotation, that aligns the guide with excellent accuracy for device positioning (<0.5 mm at 12 cm depth). Our Phase I innovation proved a brain guide could be rapidly aligned with only one image acquisition. Phase II innovation centers on opportunities discovered in formal customer interviews: 1) radically simplify fixation of the guide relative to the skull; 2) automate computation of AccuGyd’s 3D orientation; and 3) create CT compatibility. The Phase II will culminate in an efficient surgical workflow and regulatory planning for FDA 510(k) application. AccuGyd can significantly lower the barrier for image guided procedures, improving capacity for emerging treatments.