Introduction: The range of procedures that can currently be performed with a neuro-endoscope are limited. Dextrous neuroendoscopic tools offer the potential to advance intraventricular endoscopic surgery for a wide range of pathologies, particularly within the third ventricle. Prototype tools made from the shape memory alloy Nitinol meet the size, dexterity and force requirements for intraventricular surgery. The design specifications for the dimensions and shape of these novel dexterous tools requires: Defining the geometry of relevant anatomical structures in endoscopic third ventriculostomy (ETV) and pineal region tumor biopsy/excision (ETBE); determining the optimal curved instrument shaft shapes for performing a single burr hole combined ETV/ETBE.
Methods: MR and CT data from fifteen pediatric patients who underwent both ETV and ETB procedures between 2006 and 2014 was segmented using the 3DSlicer software package to create virtual 3D patient models. Anatomical regions of interest were measured including the foramen of Monro (FM), the massa intermedia (MI), the floor of the third ventricle and the tumor margin. Utilizing the MATLab software package, virtual dexterous instruments consisting of straight and curved segments were inserted into the 3D patient models, and the instruments’ optimal lengths and curvatures were determined.
Results: The diameters of the FM, MI (Anterior-Posterior), MI (Superior-Inferior), antTV and TM are 6.85mm, 4.01mm, 5.05mm, 14.2mm and 28.51 mm respectively. Dexterous instruments with straight segments of 66.3mm and curved segments of 35.9mm and with tip radius of curvatures from straight to 36.1mm satisfied the safe corridor and workspace requirement for EVT/ETBE. Optimal trajectories to the third ventricle, within these design constraints was also determined.
Conclusions: We have established a platform for estimating the shape of curved dextrous tools capable of targeting multiple points within the third ventricle, for single corridor ETV/ETBE. This data will be used to refine currently developed robotic and manual instrument platforms.
Patient Care: This work aims to improve the minimally invasive access to the ventricles through patient and procedure specific tools
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Understand the role of curved, procedure specific instruments in neuroendoscopy, 2) Describe the geometry of the anatomical features of ETV/ETB, 3) Understand the design requirements of dexterous neuroendoscopic tools.