Robotic versus freehand needle positioning in CT-guided ablation of liver tumors: A randomized controlled trial

Abstract

Background: The purpose of this study is to compare the accuracy of freehand versus robotic antenna placement in CT-guided microwave ablation (MWA) of liver tumors. Materials and Methods: This study was conducted as a prospective single-center nonblinded randomized controlled trial. Patients indicated for CT-guided MWA of liver tumors and able to receive a CT contrast agent were included. Randomization was performed per tumor after identification on contrast enhanced CT images. The primary outcome was the number of antenna repositionings, which was compared by using the Mann-Whitney U test. Secondary outcomes were lateral targeting error stratified by in-plane and out-of-plane targets. Results: Between February 14 and November 12, 2017, 31 participants with a mean age of 63 years (range, 25–88 years) were included: 17 women (mean age, 57 years; range, 25–77 years) and 14 men (mean age, 70 years; range, 52–88 years). The freehand study arm consisted of 19 participants, while the robotic study arm consisted of 18 participants; six participants with multiple tumors were included in both arms. Forty-seven tumors were assessed; five tumors were excluded from the analysis because of technical limitations. In the robotic arm, no antenna repositioning was required. In the freehand arm, a median of one repositioning was required (range, zero to seven repositionings; P<.001). For out-of-plane targets, lateral targeting error was 10.1 mm ± 4.0 and 5.9 mm ± 2.9 (P = .007) for freehand and robotic procedures, respectively, and for in-plane targets, lateral targeting error was 6.2 mm ± 2.7 and 7.7 mm ± 5.9, respectively (P = .51). Conclusion: Robotic antenna guidance reduces the need for antenna repositioning in microwave ablation to accurately target liver tumors and increases accuracy for out-of-plane targets.Tabled 1