Evaluation of a Novel, Bedside, Ultrasonographic Neuronavigation System Versus Free-Hand Ventricular Targeting: A Double-Blinded, Prospective, Paired Comparison Study

BACKGROUND AND OBJECTIVES: External ventricular drain (EVD) placement is a common neurosurgical procedure. Inaccurate placement can lead to significant complications and neurological morbidity. We present a prospective, repeated-measures experiment evaluating a novel, ultrasonographic neuronavigation device designed to improve first-pass EVD accuracy and reduce complications. METHODS: A total of 25 volunteers ranging from first-year medical students to neurosurgical attendings with over 40 years of neurosurgical experience placed titanium wires imitating EVD stylets into 3-dimensional-printed head models that included molded brains containing simulated ventricles with a brain shift. Each participant was shown a computed tomography scan of the model for planning purposes. Simulated bilateral burr holes at Kocher's point were already in position. Each participant was instructed to place a stylet through each of the bilateral burr holes and into the frontal horn of the ipsilateral ventricle. All participants placed stylets bilaterally into one model using a free-hand technique and into a second using ultrasound navigation. The models were then imaged using a computed tomography scanner (participants were blinded to the scan results). The scans were interpreted by a blinded, independent attending neuroradiologist. Paired T -tests, logistic regression, and independent T -tests were used to analyze the data. RESULTS: A total of 8.0% of the free-hand stylets were placed with the tip in the desired target of the ipsilateral frontal horn compared with 86% of the ultrasound-navigated stylets ( P < .001). The mean miss margin was 7.9 mm on the left side and 8.57 mm on the right for free-hand placement and 0.43 mm and 0.48 mm, respectively, for ultrasound-navigated placement ( P < .001). A total of 98% of the ultrasound-navigated placements were in the ventricular system compared with only 10% of the free-hand placements. CONCLUSION: In this blinded laboratory study, ultrasound-navigated placement of simulated EVD stylets was significantly more accurate than conventional free-hand placement, regardless of the participant's level of neurosurgical training.