Design and Experimental Validation of an Active Catheter for Endovascular Navigation

Abstract

Endovascular technique has many advantages but relies strongly on operator skills and experience. Robotically steerable catheters have been developed but few are clinically available.We describe here the development of an active and efficient catheter based on Shape Memory Alloys (SMA) actuators.We first establish the specifications of our device considering anatomical constraints. We then present a new method for building active SMA-based catheters. The proposed method relies on the use of a core body made of three parallel metallic beams and integrates wire-shaped SMA actuators. The complete device is encapsulated into a standard 6F catheter for safety purposes.A trial-error campaign comparing 70 different prototypes is then conducted to determine the best dimensions of the core structure and of the SMA actuators with respect to the imposed specifications. The final prototype is tested on a silicon-based arterial model and on a 23-kg pig.During these experiments we were able to cannulate the supra-aortic trunks and the renal arteries with different angulations and without any complication. * Corresponding authorA second major contribution of this paper is the derivation of a reliable mathematical model for predicting the bending angle of our active catheters. We first use this model to state some general qualitative rules useful for an iterative dimensional optimization. We then perform a quantitative comparison between the actual and the predicted bending angles for a set of 13 different prototypes. It happens that the relative error is less than 20% for bending angles between 100° and 150° which is the interval of interest for our applications.challenging and may result in an unsuccessful procedure. In most cases, several material exchanges are needed in one procedure, increasing the operative time. Several endovascular robotic systems have been developed to improve catheter navigation and reduce both the operating time and material.

Steerable catheters for minimally invasive surgery: a review and future directions

“…The catheter with SMA wires is packaged in the case of injury of the vessel wall by the heat. Similar catheters for neuroradiology can be found in [13,72].…”

“…The maneuverability of pre-curved nitinol catheters is relatively poor, as catheters are not articulated in terms of their structure. Such a catheter usually needs to work in a semi-automatical manner (i.e., works with the human operator)see the work of Couture and Szewczyk [72]. This semi-automated system concept is a basic reason that such catheters are ususally simple in their structure and easy for manufacturing.…”

“…The entire system should be viewed as a human-machine (surgeon-catheter) system [19]. It is worth to mention that a promising work of Couture and Szewczyk [72] is in fact a humandevice systemthe rotation of the cathter requires a manual operation. Neverthelss, the operability of steerable catheters, collaborated the human physciain, is not discussed in literature, which warrants a future work.…”

Steerable OCT catheter for real-time assistance during teleoperated endoscopic treatment of colorectal cancer

“…As such, this design is limited to use with interventional endoscopes. Other more advanced methods of catheter bending such as those based on soft materials such as shape memory effect catheterization [47,48], concentric tubes [49,50], conducting polymers [51,52], hydraulic pressure driven catheters [53] could be investigated to steer an OCT probe, to further decrease the outer diameter and enable use with other endoscopes adopted into the standard of care.…”

Developments and Control of Biocompatible Conducting Polymer for Intracorporeal Continuum Robots

“…In order to reduce invasiveness of medical/surgical operations and to improve standard endoscopes' accuracy, this paper introduces a novel biocompatible microactuation technique of tubes able to house diagnosis tools to perform fiber-based optical biopsy or laser surgery. The possible embedded techniques of micro-actuation include hydraulic actuation, 12 shape memory alloys, 8 and piezoelectric actuators, 13 among others. The major drawbacks of these techniques for our target application comprise the complexity of the control, the additional heat, or the need for high power.…”