Tablet-guided Versus Freehand (Tab-Guide) Ventriculostomy : Study Protocol to the Test Accuracy of Ventriculostomy in a Randomized Controlled Trial

Background: Despite the widespread use of external ventricular drainage, revision rates and associated complications are reported between 10-40%. Current available image-guided techniques using stereotaxis, endoscopy or ultrasound for catheter placements remain time-consuming techniques. Recently, a phone-assisted guide with high precision has been described. The development of an easy-to-use, portable, image-guided system could reduce the need for multiple passes and improve the rate of accurate catheter placement. This study aim to compare prospectively in a randomized controlled manner the accuracy of the freehand pass technique versus an an easy-to-use, portable mini-tablet-assisted guide for ventriculostomy catheter placement.

Methods/Design: This is a single center, prospective, randomized, trial with blinded endpoint (ventricle catheter tip location) assessment. Adult patients with the indication for ventriculostomy, as proven by computed tomography (CT), will be randomly assigned to the treatment group or the control group. In patients of the treatment group, ventriculostomy will be performed using a mini-tablet-guided assistance based on preoperative CT imaging. Patients in the control group will receive standard free-hand ventriculostomy using anatomical landmarks. The catheter may be placed for external drainage or internal (ventriculoperitoneal) shunting in both groups. The primary outcome measure is rate of correct placements of the ventricular catheter, defined as a score of 1 to 3 on grading system for catheter tip location on postoperative CT scan. Primary outcome will be determined by one of the authors (NS) blinded for treatment allocation. We aim to include 320 patients in 3 years.

Secondary Outcome Measures include 1) Frequency of placements required, 2) Frequency of completed placements within the ventricle of the perforated part of the tip of the catheter, 3) Frequency of very early and early shunt failures (revision of the ventricular drainage within 24 hours / within three weeks, 4) Frequency and Percentage of complications (procedure-related and nonsurgical) within three weeks, 5) Length of the trajectories from the dura level to the foramen of Monroe, the angle in the coronal plane towards midline (a) and towards the target (b) at the respective entry point, 6) ventricle size (the frontal occipital horn ratio (FOHR) and the width of the lateral ventricle in the coronal plane between the medial wall of the corpus callosum and the septum), 7) Differences (angles, distance of catheter tip from target) on the tablet-guided planned and postoperative trajectory on control computer tomography within 48 hrs (CT).

Discussion: Here, we present the study design of a single center prospective randomized controlled trial to investigate whether tablet-guided application ventriculostomy is superior to the standard free hand technique. The strengths of this study are: 1. the prospective, randomized interventional character testing a new easy-to handle guided versus free-hand ventricular catheter placement, and 2. the power calculation is based on catheter accuracy using an available grading system for catheter tip location and calculated with use of recent study results of our own population, supported by data from prominent studies.