Electromagnetic neuronavigation in neuroendoscopy. Navigation proposal for the LOTTA ventriculoscope. Technical note.

Background and objective: Neuronavigation in ventriculoscopy has been described in several papers. However, there are different ventriculoscopes and navigation systems. Because of these different combinations, it is difficult to find detailed navigation protocols for each ventriculoscope. We describe, step by step, a simple method to navigate both the trajectory to reach the ventricular system and the intraventricular work for the LOTTA ventriculoscope.

Methods: We used a rigid ventriculoscope (LOTTA, KarlStorz) with an electromagnetic stylet (S8-StealthSystem, Medtronic) as the main navigation tool. The protocol is based on a 3D printed trocar or alternatively, on a modification of the original trocar for extraventricular phase navigation and a modified pediatric nasogastric tube for intraventricular phase navigation.

Results: The protocol can be set up in less than 10min. The extraventricular part is navigated by inserting the electromagnetic stylet inside the 3D printed trocar or inside the original modified trocar. Intraventricular navigation is performed by combining a modified pediatric nasogastric tube with the electromagnetic stylet inside the working channel of the endoscope. The most critical point is to obtain a blunt, bloodless approach to the ventricle and to achieve perfect alignment of all target structures by means of previously planned pure straight trajectories.

Conclusions: This protocol is easy to set up, avoids rigid head fixation, bulky optical navigation accessories, while allows continuous navigation of both parts of the surgery. Since we have implemented this protocol, we have seen a significant improvement in both simple and complex neuroendoscopy procedures as the surgery is dramatically simplified.