Steerable needles for radio-frequency ablation in cirrhotic livers

• Published in: Scientific reports Vol. 11; no. 1; p. 309
• Main Authors: van de Berg, Nick J., Meeuwsen, Frédérique C., Doukas, Michail, Kronreif, Gernot, Moelker, Adriaan, van den Dobbelsteen, John J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.01.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/166/985; 692/4028; Ablation; Explants; Histology; Humanities and Social Sciences; Liver; Liver cirrhosis; Mimicry; multidisciplinary; Needles; Science; Science (multidisciplinary); Surface area; Tumors; Ultrasound
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-77869-3

Accurate needle placement in deep-seated liver tumours can be difficult. In this work, we disclose two new manually controlled steerable needles for 17G radio-frequency ablation probe placement. The needles contain stylets with embedded compliant joints for active tip articulations, and concentric tubes for (curved-path) guidance. Needle steering was evaluated sequentially by intended users and in intended-use tissue types. Six interventional radiologists evaluated the needle in repeated ultrasound-guided steering tasks in liver-mimicking phantoms. Targets were located at a 100 mm depth and 20 mm lateral offset from the initial insertion line. The resulting mean absolute tip placement error was 1.0 ± 1.0 mm. Subsequently, steering-induced tissue damage was evaluated in fresh cirrhotic human liver explants. The surface area of puncture holes was estimated in scanned histology slides, using a connected-components analysis. The mean surface area was 0.26 ± 0.16 mm 2 after steering with a median radius of curvature of 0.7 × 10 3  mm, versus 0.35 ± 0.15 mm 2 after straight-path insertions with the steerable needle and 0.15 ± 0.09 mm 2 after straight-path RFA probe insertions. The steering mechanisms proposed enable clinically relevant path corrections for 17G needles. Radiologists were quickly adept in curved-path RFA probe placement and the evaluation of histological tissue damage demonstrated a potentially safe use during liver interventions.