Behavior of Tip-Steerable Needles in Ex Vivo and In Vivo Tissue

A. Majewicz, S. P. Marra, M. G. van Vledder, MingDe Lin, M. A. Choti, D. Y. Song, A. M. Okamura
2012 IEEE Transactions on Biomedical Engineering  
Robotic needle steering is a promising technique to improve the effectiveness of needle-based clinical procedures, such as biopsies and ablation, by computer-controlled, curved insertions of needles within solid organs. In this paper, we explore the capabilities, challenges, and clinical relevance of asymmetric-tip needle steering though experiments in ex vivo and in vivo tissue. We evaluate the repeatability of needle insertion in inhomogeneous biological tissue and compare ex vivo and in vivo
more » ... needle curvature and insertion forces. Steerable needles curved more in kidney than in liver and prostate, likely due to differences in tissue properties. Pre-bent needles produced higher insertion forces in liver and more curvature in vivo than ex vivo. When compared to straight stainless steel needles, steerable needles did not cause a measurable increase in tissue damage and did not exert more force during insertion. The minimum radius of curvature achieved by pre-bent needles was 5.23 cm in ex vivo tissue, and 10.4 cm in in vivo tissue. The curvatures achieved by bevel tip needles were negligible for in vivo tissue. The minimum radius of curvature for bevel tip needles in ex vivo tissue was 16.4 cm; however, about half of the bevel tip needles had negligible curvatures. We also demonstrate a potential clinical application of needle steering by targeting and ablating overlapping regions of cadaveric canine liver. NIH Public Access
doi:10.1109/tbme.2012.2204749 pmid:22711767 pmcid:PMC3448818 fatcat:c5yxcf6v2fdizenelgh6ep66wa