gms | German Medical Science

Objective: Up to 40% of external ventricular drainages (EVD) are placed suboptimally and are complicated frequently by multiple attempts when primary anatomical landmarks are used for insertion. Therefore, the authors investigated the feasibility and accuracy of smartphone-guided angle-adjusted EVD implantation in both a human artificial and a cadaveric cranium.

Method: On multi-planar 3D reformatted cranial CT a trajectory was set from Kocher’s point to the center of the ipsilateral ventricular frontal horn according to the horizontal and vertical diameter. Intended insertion angles and distances to the catheter tip were measured. A smartphone was calibrated to the mid-cranial sagittal line with the skull in a neutral position. A total of 20 EVD (skull phantom 8/20, cadaver head 12/20) were inserted using both the measured catheter lengths and smartphone-adjusted implantation angles. Insertion angles and intracranial distance to the catheter tip were measured on postinterventional CT.

Results: 20/20 EVD were placed optimally in the frontal horn of the ipsilateral ventricle at the first attempt. The inserted EVD showed a mean deviation of 2.76° from the planned trajectory with a 1.93° standard deviation (SD). The mean distance of the EVD tips to the intended target was 0.4 cm (SD ± 0.26 cm). The mean duration of measurement of implantation angles and intraventricular lengths was 3 min, and of sterile packing, calibration of the smartphone and angle-adjusted EVD insertion 4 min, respectively.

Conclusions: For the first time, a smartphone was used as a tool for EVD insertion. Our ex vivo study suggests that smartphone-guided EVD placement represents a precise and fast assisted free-hand technique with a simple and broadly available device. Future in vivo studies might help to implement our method into clinical routine.