Utility of Preoperative Simulation for Ventricular Catheter Placement via a Parieto-Occipital Approach in Normal-Pressure Hydrocephalus.

Abstract

Freehand ventricular catheter placement has been reported to have poor accuracy. To investigate whether preoperative computational simulation using diagnostic images improves the accuracy of ventricular catheter placement. This study included 113 consecutive patients with normal-pressure hydrocephalus (NPH), who underwent ventriculoperitoneal shunting via a parieto-occipital approach. The locations of the ventricular catheter placement in the last 48 patients with preoperative virtual simulation on the 3-dimensional workstation were compared with those in the initial 65 patients without simulation. Catheter locations were classified into 3 categories: optimal, suboptimal, and poor placements. Additionally, slip angles were measured between the ventricular catheter and optimal direction. All patients with preoperative simulations had optimally placed ventricular catheters; the mean slip angle for this group was 2.8°. Among the 65 patients without simulations, 46 (70.8%) had optimal placement, whereas 10 (15.4%) and 9 (13.8%) had suboptimal and poor placements, respectively; the mean slip angle for the nonsimulation group was 8.6°. The slip angles for all patients in the preoperative simulation group were within 7°, whereas those for 31 (47.7%) and 10 (15.4%) patients in the nonsimulation group were within 7° and over 14°, respectively. All patients with preoperative simulations experienced improved symptoms and did not require shunt revision during the follow-up period, whereas 5 patients (7.7%) without preoperative simulations required shunt revisions for different reasons. Preoperative simulation facilitates accurate placement of ventricular catheters via a parieto-occipital approach. Minimally invasive and precise shunt catheter placement is particularly desirable for elderly patients with NPH.