Day: August 21, 2026

Neurosurgery  2026;99(2):479–486

External ventricular drain placement is commonly performed using anatomical landmarks, but free-hand trajectories may miss the ventricle or traverse unintended brain structures. This prospective bench study compared conventional targeting with a portable bedside ultrasound-navigation system. Twenty-five participants of widely different experience levels performed paired procedures in realistic head models incorporating simulated brain shift. Ultrasound guidance substantially improved ventricular entry and frontal-horn targeting. These accuracy results are compelling, but clinical benefit and safety still require confirmation in patients.

Objective

To compare the accuracy of a novel bedside ultrasonographic neuronavigation system with conventional free-hand ventricular targeting across operators with different levels of neurosurgical experience.

Methods

In a prospective, double-blinded, paired-comparison experiment, 25 participants ranging from first-year medical students to attending neurosurgeons with more than 40 years of experience placed titanium wires simulating external ventricular drain stylets into three-dimensional printed head models.

The anatomically realistic models contained molded brains, simulated ventricles and brain shift. Each participant used both free-hand landmarks and ultrasound-guided navigation, allowing within-operator comparison of ventricular entry, ipsilateral frontal-horn targeting and distance from the intended target.

Main results

Ultrasound-guided trajectories entered the ventricular system in 98% of attempts, compared with 10% using the free-hand technique. The intended ipsilateral frontal horn was reached in 86% versus 8%, respectively (p<0.001).

Mean distance from the intended target was less than 0.5 mm with ultrasound guidance and nearly 8 mm with free-hand placement (p<0.001). The navigation system improved first-pass accuracy across all represented levels of operator experience.

Interpretation

Real-time portable ultrasound may reduce the dependence of ventricular catheter placement on surface landmarks, particularly when ventricular size or brain shift makes the conventional trajectory unreliable. The magnitude and consistency of the accuracy improvement justify clinical evaluation, but model performance cannot establish a reduction in hemorrhage, infection, revision or functional morbidity.

Limitations

This was a bench-model study rather than a clinical trial. Printed anatomy cannot reproduce tissue deformation, bleeding, narrow or distorted ventricles, patient movement or the time pressure of emergency care. Some investigators were associated with the device, making independent replication important. Procedure time, learning curve, complications and patient outcomes were not evaluated.

Clinical takeaway

Bedside ultrasound navigation has the potential to make ventricular access more accurate and less operator-dependent. Before routine adoption, the system requires prospective clinical comparison with free-hand placement and established navigation methods, including first-pass success, catheter grade, hemorrhage, infection, revision, workflow and cost.