Guida per posizionamento di cateteri cerebrali

Background: external ventricular drain (EVD) placement is mandatory for several pathologies. The misplacement rate of the EVD in the literature varies widely, ranging from 12.3% to 60%. The purpose of this study is to provide preliminary data about the possibility of increasing the safety of one of the most common life-saving procedures in neurosurgery by testing a new device for EVD placement. Methods: we used a novel guide for positioning the ventricular catheter (patent RM2014A000376). The trajectory was assessed using 25 anonymized head CT scans of patients. The data set were used to con-duct three-dimensional computer-based and combined navigation and augmented reality-based simulations using plaster models. The data set inclusion criteria were volumetric head CT scan without midline shift of patients who are above 18 years old. Evans ratio was used to quantify the ventricle’s size. We excluded patients with slit ventricles, midline shift, skull fractures, and complex skull malformations. The proximal end of the device was tested on the cadaver. Results: the cadaveric tests proved that only one surgeon could use the device. The multimodal simulation showed Kakarla grade 1 in all cases but one with grade 2, on both sides after right and left EVD placement. The mean Evans ratio was 0,28. The geometric principles that explain the device's efficacy can be summarized by studying the geometric properties of circumference and chord. The contact occurs for each section considered at the extreme points of the chord. Its axis, perpendicular to the plane tangent to the spherical surface at the entry point, corresponds to the direction of entry of the catheter guided by the instrument. Conclusions: according to our multimodal simulation through cadaveric, 3D computer-based simulation, 3D plaster modeling, 3D neuronavigation, and augmented reality, the device will offer safer and effective EVD placements.