Assessment of White Matter Transgression During Neuroendoscopic Procedures Using Diffusion Tensor Image Fiber Tracking

Background Presurgical planning allows anticipating intraoperative difficulties, increasing efficiency, and reducing risks. Neuroendoscopy is a minimally invasive technique whose related complications have been focused on cortical function and surface vessels injury. However, white matter disruption has been insufficiently acknowledged. Objective To present a new surgical planning method based on diffusion tensor image that allows quantifying subcortical transgression and optimizing neuroendoscopic trajectories. Methods Ten cranial magnetic resonance studies (20 sides) without pathologic findings were anonymized and processed. A standard transcortical approach to the frontal horn was used to study the transgression of the corpus callosum (CC) and cingulum (Ci) caused by a virtual endoscope (VE) oriented from the Kocher point to the foramen of Monro. An 8-mm VE model was created, oriented, and coregistered. VE-CC and VE-Ci intersections were segmented. The number and volume of injured fibers were measured, intersections were quantified, and the percentage of tract transgression was calculated. The areas damaged by the VE were also recorded. Results Among the CC fibers, 16.4% were injured (range: 3.3%–37%) and 26.7% of fibers on Ci (rank: 0%–73.4%). The average intersected volumes were 19.1% (range: 4.2%–53.2%) for CC and 33.2% for Ci (range: 0%–73.7%). Qualitative analysis showed the lateral aspect of both tracts as the most frequently injured region. No hemispherical asymmetry was found ( P > 0.05). Conclusion This method using tractography and oriented models of surgical instruments allows assessing white matter transgression, both qualitatively and quantitatively, for a deep brain trajectory. Thus our method permits surgeons to optimize safety and avoid transgression of eloquent tracts during surgical planning. Nevertheless, more studies are necessary.