Team AVR - Control, Vision and Robotics Lab

Cardiolock & Gyrolock - Active stabilization for beating heart surgery

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Scope

In cardiac surgery, coronary artery bypass grafting is still often performed after stopping the heart, using an external heart-lung machine. Today, the only solution to perform surgery on a beating heart is to suppress locally the beating heart motion by using a so-called stabilizer. This device is composed of a long shaft to reach the area of interest. Its performance remains however limited: significant displacements can still be observed.

In the Gyrolock and Cardiolock projects, the principle of active stabilization has been introduced. The stabilizer is designed as an active device, that is controlled to suppress in real time any displacement of the area of interest. The Cardiolock device uses piezoelectric actuation combined with a compliant mechanism and high-speed vision as an exteroceptive measurement. In the Gyrolock project, the gyroscopic effect is used to generate a force that counterbalances the force applied by the heart on the stabilizer tip. Accelerometers are then used to get an estimation of the stabilizer motion. Both approaches have been proved to be efficient, with successful in vivo evaluation.

Cardiolock.jpg Gyrolock.jpg

Keywords: compliant mechanisms, beating heart surgery, gyroscopic effect, visual servoing, control

Contacts

Pierre Renaud, Olivier Piccin, Edouard Laroche, Jacques Gangloff

Cardiolock

The Cardiolock device is designed using compliant mechanisms that convert PZT displacement into a stabilizer shaft motion cancelling the motion estimated using vision. An original design has been introduced for the Cardiolock 2 device, that takes advantage of the vicinity of singularity of parallel mechanisms to convert the translation provided by the actuator into a shaft rotation.


Major facts

  • In vivo demonstration of the efficiency of both devices
  • IEEE Robio 2010 Best Paper for the Gyrolock project
  • MICCAI 2007 Best Student Paper for W. Bachta, Cardiolock project