In this paper, we validate the effectiveness of the optimal planning algorithms we have developed for devising surgical plans for Percutaneous Nephrolithotomy (PCNL) using patient-specific Concentric-Tube Robots (CTRs). To do so, we built a life-sized phantom model of the right hemithorax, replicating the anatomy of a patient who suffered from kidney stone and underwent conventional PCNL. Two-dimensional CT scans of the phantom model and its 3D reconstruction enabled the creation of a surgical plan using our planning algorithms based on a puncture into the mid-pole of the kidney. This was compared with two other percutaneous tracts involving punctures into the lower and upper calyces for comparison. The optimal mid-pole plan achieved 84% stone coverage, significantly outperforming the lower pole (58 %) and upper pole (45 %) plans. These results validate the effectiveness of the algorithms and align with simulation-based findings from previous studies, which reported an average volume coverage of 81.6±19.6 % in clinical cases.

Catheter-based cardiac ablation is the preferred method of treating atrial fibrillation. Conventionally, the catheter is navigated in the heart using X-ray fluoroscopy imaging and an electroanatomical map. Although successful, these imaging modalities do not provide real-time feedback on the quality of lesions created, which in turn could lead to recurrence of arrhythmia. Intracardiac echo (ICE) catheter provides real-time imaging within the heart to visualize both the ablation catheter and lesions created. However, manipulating the ablation and ICE catheters simultaneously is tedious and time consuming. As a first step towards developing a robotic ICE catheter that can autonomously follow the ablation catheter and monitor the lesions, we have developed a dynamic model for the ICE catheter. The model is based on the Cosserat theory for flexible rods that relies on strain parametrization. The model also accounts for frictional forces between the catheter sheath and tendons, external loads and fluid forces acting on the catheter. A good nominal model for describing the catheter dynamics is essential to develop a robust control scheme for the robotic ICE catheter. The parameters of the ICE catheter are estimated using weight release, tendon-driven actuation and fluid flow experiments. To the best of our knowledge, this is the first dynamic model for the ICE catheter that accurately reflects the dynamics of the catheter under pulsatile fluid flow within a heart phantom.

This paper applies the CVIU (Control Variation Increases Uncertainty) approach to a discrete time scenario. Important solution characteristics are indicated, which conceptually preserves the findings in the continuous time case presented in [1]. Mainly, the arising of three control regions in the state space and the association of the value function with a discrete Lyapunov and a modified Riccati equation. The former holds within the inaction region, which is near the origin, and the latter holds for regions far from the origin. The SISO case is developed in full and, in conjunction, a comparison with the LQG solution is presented. An evaluation on the system's performance in the context of poorly known systems closes the paper.