Autonomous robotic intracardiac catheter navigation using haptic vision

International audienceWhile all minimally invasive procedures involve navigating from a small incision in the skin to the site of the intervention, it has not been previously demonstrated how this can be done 10 autonomously. To show that autonomous navigation is possible, we investigated it in the hardest place to do it-inside the beating heart. We created a robotic catheter that can navigate through the blood-filled heart using wall-following algorithms inspired by positively thigmotactic animals. The catheter employs haptic vision, a hybrid sense using imaging for both touch-based surface identification and force sensing, to accomplish wall following inside the blood-filled heart. 15 Through in vivo animal experiments, we demonstrate that the performance of an autonomously-controlled robotic catheter rivals that of an experienced clinician. Autonomous navigation is a fundamental capability on which more sophisticated levels of autonomy can be built, e.g., to perform a procedure. Similar to the role of automation in fighter aircraft, such capabilities can free the clinician to focus on the most critical aspects of the procedure while providing precise and 20 repeatable tool motions independent of operator experience and fatigue

A novel fluid driven, foldable joint for minimally invasive surgery

In minimally invasive surgery (MIS) the aspect of miniaturization is getting more and more demanding. On the other hand, it is also important to assure high stability and large actuation forces at the end effector. Here we present the design and the development of a 1 degree of freedom (DOF) rotational joint, which combines a foldable mechanism and a fluidic actuation system for obtaining force magnification within a slender structure (diameter = 5 mm). The foldable mechanism is composed of identical rigid elements connected each other, which sequentially move away from the joint's axis and ensure an output torque of 0.5 Nm

Analysis of the structural behaviour of a colonic segment by inflation test: experimental activity and physio-mechanical model

A coupled experimental and computational approach is provided for the identification of the structural behaviour of gastrointestinal regions, accounting for both elastic and visco-elastic properties. The developed procedure is applied to characterize the mechanics of gastrointestinal samples from pig colons. Experimental data about the structural behaviour of colonic segments are provided by inflation tests. Different inflation processes are performed according to progressively increasing top pressure conditions. Each inflation test consists of an air in-flow, according to an almost constant increasing pressure rate, such as 3.5 mmHg/s, up to a prescribed top pressure, which is held constant for about 300 s to allow the development of creep phenomena. Different tests are interspersed by 600 s of rest to allow the recovery of the tissues' mechanical condition. Data from structural tests are post-processed by a physio-mechanical model in order to identify the mechanical parameters that interpret both the non-linear elastic behaviour of the sample, as the instantaneous pressure-stretch trend, and the time-dependent response, as the stretch increase during the creep processes. The parameters are identified by minimizing the discrepancy between experimental and model results. Different sets of parameters are evaluated for different specimens from different pigs. A statistical analysis is performed to evaluate the distribution of the parameters and to assess the reliability of the experimental and computational activities

In Vivo Molding of Airway Stents

Like ready-to-wear clothing, medical devices come in a fixed set of sizes. While this may accommodate a large fraction of the patient population, others must either experience suboptimal results due to poor sizing or must do without the device. Although techniques have been proposed to fabricate patient-specific devices in advance of a procedure, this process is expensive and time consuming. An alternative solution that provides every patient with a tailored fit is to create devices that can be customized to the patient's anatomy as they are delivered. This paper reports an in vivo molding process in which a soft flexible photocurable stent is delivered into the trachea or bronchi over a ultraviolet (UV)-transparent balloon. The balloon is expanded such that the stent conforms to the varying cross-sectional shape of the airways. UV light is then delivered through the balloon curing the stent into its expanded conformal shape. The potential of this method is demonstrated using phantom, ex vivo, and in vivo experiments. This approach can produce stents providing equivalent airway support to those made from standard materials while providing a customized fit

Non-surgical Removal of Partially Absorbable Bionic Implants

Bionic implants offer the potential to augment human performance and to assist the body in recovering functions lost to disease. While some may be permanently implanted, others provide temporary support. The challenge for the second case is how to remove the device from the body once its task is complete without forcing the patient to undergo a second surgical procedure. While some devices may be fabricated entirely from absorbable materials, this may not always be possible. This paper investigates a strategy in which an implant is fabricated from a combination of absorbable and non-absorbable materials with the latter connected by a tether to the skin. At the time of removal, the device is disassembled in situ such that the absorbable components can remain in place while the non-absorbable components can be removed non-surgically by pulling them out of the body by the tether. The concept is demonstrated in the context of an implant that induces bowel growth by applying traction forces over a several-week period. In vivo experiments in swine are used to validate the approach