Exploring the aorta with the ‘snake robot’

The development of robots for medical applications in the human cardiovascular system poses a particular challenge for research because robot-controlled catheters have to navigate in a complex, sensitive, deformable and highly dynamic environment that only offers very limited options in terms of freedom of movement and visualisation. In the EU-sponsored CASCADE (Cognitive Autonomous Catheter Operating in Dynamic Environments) project and as part of an international consortium, the ZHAW School of Engineering is developing a control system for a snake-like robot that should overcome this challenge.

Navigating through the aorta

“This catheter, equipped with robotics and sensors, can be used for minimally invasive operations known as ‘keyhole’ surgeries,” explains Dr Dejan Šeatović, who is heading the project on behalf of the ZHAW Institute of Mechatronic Systems (IMS). The main task of the IMS is the development of a software environment that unites all of the subcomponents in a general system. These components may include hardware drives, data-processing modules and visualisation tools. A significant requirement for the system is therefore a modular construction that guarantees system stability. The individual modules are run as separate processes on the CASCADE control computer – meaning that failure of an individual module will only affect certain functions but will not cause the entire system to crash. 

Constant monitoring thanks to visualisation

The software environment will be easy to use for both developers and scientists as well as end users. The system is designed in such a way that expansions can be added easily and quickly depending on future requirements. In addition to providing technical support for the catheter, Dejan Šeatović is primarily in charge of expediting the development of  graphic user interface. This would offer the operating surgeons a comprehensive visualisation of the surgery environment and also enable direct interventions in the operation procedure with the constant monitoring of the catheter. 

Increased patient safety

A significant advantage of the new system is increased patient safety, thanks to automated procedures and the reduction of radiation exposure. Data collected before the operation with the magnetic resonance tomography can be linked to the sensor data during the operation and allows three-dimensional modelling of the surgical setting – without using any x-rays. The functionality of the newly developed catheter is to be demonstrated at the end of the project with the automated implantation of a heart valve in a test setting using the catheter. The researchers developed a realistic test environment specifically for this purpose composed of an artificial, silicone-type aorta with a heart chamber. The project will not be completed until 2016, but Dejan Šeatović is already drawing a positive conclusion from the interim results: “With the precise and comprehensive three-dimensional visualisation of the operation, we have achieved an important technological innovation together with our partners. We are enabling the first-ever detailed monitoring of the position, orientation and shape of the catheter in the aorta without having to expose the patient to ionised radiation.”