External ventricular drain (EVD) placement is a routinely performed neurosurgical procedure that plays a crucial role in a treatment of acute hydrocephalus and provides intracranial pressure monitoring. Kocher´s point is the most commonly used anatomical landmark for the procedure. In several cases, other anatomical landmarks must be used in order to perform the procedure safely and successfully. In such cases, augmented reality (AR) might be the decisive factor for a successfully and safely performed procedure. The previous study (IMAGINER I) presented an improved accuracy by ventriculostomy performed by medical students without previous neurosurgical experience. In this study, we evaluate the impact of augmented reality on the accuracy of EVD placement performed by experienced neurosurgeons.

In our study, neurosurgeons perform ventriculostomies over Kaufman´s, Keen´s, Kocher´s and Fraizer´s point on a Styrofoam head. We compared ventriculostomies according to anatomical landmarks with ventriculostomies performed with the aid of the Microsoft Hololens Augmented Reality system according to a pre-planned trajectory. Subsequently, CT-Scans are performed to assess the data.

The mean target-point deviation in all ventriculostomies was 16.93 ± 9.3 mm in AR group 21.71 ± 9.5 mm in Free-hand group compared to 21.71 ± 9.5 mm in Free-hand group, with mean difference of 4.78mm (p=0.0027, CI 95% 1.68 – 7.78). After comparing separately every pre-defined ventriculostomy entry-point separately, we saw reduction in mean target point deviation in all groups with statistically significant difference in Keen´s point (Kocher´s point 16.33 ± 7.32 mm vs. 20.60 ± 6.88 mm; p=0.08, Keen´s Point 15.29 ± 7.26mm vs. 23,48 ± 11.21mm, p=0.01, Kaufman´s point 19.29 ± 12.11mm vs. 22.72 ± 11.20mm, p=0.38 and Fraizer´s point 16.82 ± 10.27mm vs. 20.03 ± 8.8mm, p=0.32).

Following the IMAGINER I results, we performed an evaluation of the augmented reality supported placement of a ventricular drain over Kaufman´s, Keen´s, Kocher´s and Fraizer´s point performed by experienced neurosurgeons. Overall, we saw a significant reduction in mean target deviation, if AR was used.