Testing of neurosurgical needle steering via duty-cycled spinning in brain tissue in vitro.

A technique for steering of flexible bevel-tipped needles through tissue, providing proportional control of trajectory curvature by means of duty-cycled rotation or spinning during insertion, has been presented previously, and tested in vitro in gelatin samples. The present paper presents the results of testing under more authentic conditions. Thirty-two needle insertions were performed in cadaver brain tissue. Needle insertion was controlled interactively by the surgeon, adjusting parameters intraoperatively as needed based on fluoroscope images acquired at intervals of 1-2 cm of insertion depth. The average target acquisition error was 1.80 +/- 1.33 mm.