Journal of medical robotics research最新文献

Focal prostate treatment (aka "male lumpectomy") has the potential to reduce invasiveness for prostate cancer patients. However, clinical deployment has been impeded by the difficulty of performing surgery through the urethra, which we hypothesize relates to both instrument dexterity and visualization limitations. To evaluate this hypothesis, in this paper we propose a system consisting of an endoscopic robot to enhance dexterity and an image-guidance display updated periodically during surgery based on MRI images. To evaluate the system, in this paper we compare four conditions: unaided manual resection using an endoscope, robot-aided surgery without image guidance, image guidance without the robot, and both robot and image guidance together. We find that while the robot and image guidance improve performance individually, the combination of the two provides the greatest improvement.

Concentric push-pull robots delivered through flexible endoscopes work best if their laser-cut transmission tubes have high axial stiffness, high torsional stiffness, and low bending stiffness. This paper simultaneously addresses all three output stiffness values in the transmission design problem, explicitly considering axial stiffness, whereas prior work on laser-cut tube design has focused on the bending/torsional stiffness ratio. We demonstrate an inherent trade-off present in existing laser-cut patterns: it is difficult to simultaneously achieve high axial stiffness and low bending stiffness because these properties are very tightly correlated. To break this correlation and design all three stiffness independently, we propose a new type of laser material removal pattern that leverages local stiffness asymmetry ( $E{I}_x\ne E{I}_y$ ) in discrete bending segments separated by segments of solid tube. These discrete asymmetric segments are then rifled down the tube to achieve global stiffness symmetry. We parameterize the design and provide a study of the properties through finite-element analysis. We also consider the effect of interference between the tubes when the discrete segments are not aligned. Results show that our discrete asymmetric segment concept can achieve high axial stiffness and torsional stiffness better than previously suggested laser patterns while maintaining equally low bending stiffness. We also experimentally validated the proposed design's properties and actuation performance with professionally manufactured prototype Nitinol tubes for use in an endoscopic robot system.

Image guidance using preoperative magnetic resonance imaging (MRI) and intraoperative ultrasound (US) can improve the outcome of spine surgery. Employing a robotic US system (RUSS) allows the automated acquisition of large 3D US volumes, facilitating accurate registration. However, such registration remains challenging due to the cross-modality discrepancy. To address this issue, we present a pipeline that extracts spine pointclouds from MRI and 3D US to perform per-vertebra registration. Experiments showed a registration accuracy of 1.82 mm in terms of residual root mean square error and 7.02 mm in terms of Chamfer distance. The pipeline exhibits superior robustness to suboptimal initial conditions compared with the two baseline methods. It also demonstrated good time efficiency under real-time conditions, demonstrating the potential applicability in RUSS-guided spine surgeries.