Objective

To evaluate accuracy of a computed tomography (CT)-guided frameless stereotactic drilling and catheter system.

Methods

A prospective, single-arm study was performed using human cadaver heads to evaluate placement accuracy of a novel, flexible intracranial catheter and stabilizing bone anchor system and drill kit. There were 20 catheter placements included in the analysis. The primary endpoint was accuracy of catheter tip location on intraoperative CT. Secondary endpoints included target registration error and entry and target point error before and after drilling. Measurements are reported as mean ± SD (median, range).

Results

Target registration error was 0.46 mm ± 0.26 (0.50 mm, -1.00 to 1.00 mm). Two (10%) target point trajectories were negatively impacted by drilling. Intracranial catheter depth was 59.8 mm ± 9.4 (60.5 mm, 38.0-80.0 mm). Drilling angle was 22° ± 9 (21°, 7°-45°). Deviation between planned and actual entry point on CT was 1.04 mm ± 0.38 (1.00 mm, 0.40-2.00 mm). Deviation between planned and actual target point on CT was 1.60 mm ± 0.98 (1.40 mm, 0.40-4.00 mm). No correlation was observed between intracranial catheter depth and target point deviation (accuracy) (Pearson coefficient 0.018) or between technician experience and accuracy (Pearson coefficient 0.020). There was no significant difference in accuracy with trajectories performed for different cadaver heads (P = 0.362).

Conclusions

Highly accurate catheter placement is achievable using this novel flexible catheter and bone anchor system placed via frameless stereotaxy, with an average deviation between planned and actual target point of 1.60 mm ± 0.98 (1.40 mm, 0.40-4.00 mm).