Stiffness sensing and palpation are essential for understanding object properties, including tissue health and fruit ripeness. Currently, there is limited research on using soft-tipped sensors for stiffness sensing and dynamic palpation. To address these challenges, we investigate how the pressure modulated optical tracking (PMOT) sensor can use compliance control to quantify tissue stiffness and detect margins in samples through dynamic palpation. Results show that the PMOT sensor modulus of elasticity sensing range is from 4.20 kPa up to 177.62 kPa. Across all untrained samples, elasticity was measured with a root-mean-square error (RMSE) of 7.72%. Further, it is shown that the sensor can locate margins between 13.4 kPa and embedded 29.3 kPa materials during palpation. When mounted on a linear rail, averaged for the direction of travel, the sensor's signal-to-noise ratio (SNR) was up to 39.5:1. Participants used the sensor to locate embedded margins in a teleoperation environment with visual feedback. This was achieved with an accuracy of 96.5%.

Transcatheter aortic valve implantation (TAVI) is a minimally invasive surgical technique to treat aortic heart valve diseases. According to current clinical guidelines, the implanted prosthetic valve replacing the native one is selected based on pre-operative size assessment of the aortic annulus through different imaging techniques. That very often leads to suboptimal device selection resulting in major complications, such as prosthetic valve leakage or interruption of the cardiac electrical signal. In this paper, we propose a new, intra-operative approach to determine the diameter of theaortic annulus exploiting intra-balloon pressure and volume data, acquired from a robotised valvuloplasty balloon catheter. An inflation device, capable of collecting real-time intra-balloon pressure and volume data, was designed and interfaced with a commercially available valvuloplasty balloon catheter. A sizing algorithm allowing to precisely estimate the annular diameter was integrated. The algorithm relies on a characterised analytical model of the balloon free inflation and an iterative method based on linear regression. In vitro tests were performed on idealised aortic phantoms. Experimental results show that pressure-volume data can be used to determine annular diameters bigger than the unstretched diameter of the balloon catheter. For these cases, the proposed approach exhibited good precision (maximum average error 0.93%) and good repeatability (maximum standard deviation ±0.11 mm).

Endovascular aneurysm repair (EVAR) is a minimally invasive approach for abdominal aortic aneurysm (AAA) treatment. Compared to open surgery, the benefits of EVAR include faster recovery and shorter time in hospital as well as no general anesthesia (in most cases). Though EVAR has become a preferred way to treat AAA with an increasing number of procedures, there are persisting complications, e.g. stent graft migration. Suturing the stent graft to the aorta increases the displacement force necessary to move the implant. This paper describes the design of a suturing catheter for EVAR. The suturing device consist of two modules which can be inserted through the femoral arteries into the abdominal aorta where both join using an electro-magnetic connector. The positioning module provides an anchor inside the aorta for the suturing module and new sequential positions for each stitch. Our large-scale prototype is validated inside a phantom vessel made of silicone material. We are able to successfully prove the concept of this novel single-sided suturing catheter for EVAR.