Tele-manipulative Neuro-registration in Robot-assisted Neurosurgery

Accurate neuro-registration is important as the success of the surgical procedure highly depends on it. This article deals with neuro-registration using tele-manipulation (Master-Slave Manipulation) to facilitate tele-surgery and enhance the overall accuracy and reach of the robot-assisted neurosurgery.

A 6 degrees-of-freedom parallel kinematic mechanism (6D-PKM) master-slave robot in tele-manipulation mode is utilized for both neuro-registration and neurosurgery. Real-time kinematic control of 6D-PKM is made possible by solving its forward kinematics using the trajectory modifier algorithm with an accuracy of 1 μm and 0.001° in translation and orientation, respectively, in real time. The master operator using the 6D-PKM master mechanism moves the 6D-PKM slave robot equipped with a touch probe stylus (4 mm diameter) in tele-manipulation mode. In neuro-registration, the slave is remotely guided to touch the fiducial marker in a predetermined order. A correlation between the medical image space and the real patient space is made to establish the neuro-registration. The accuracy of neuro-registration is validated through experiments on skull phantoms. These phantoms are designed to simulate the neurosurgical process.

The neuro-registration process successfully registers the phantoms, and maximum registration error is found to be 0.6 mm. The accuracy of neurosurgery is validated using several target points in phantom. The accuracy of registration is also verified by robot piercing a 2-mm-diameter surgical needle through a predesignated 3-mm-diameter cylindrical target hole with radial clearance of 500 μm.

Accurate neuro-registration using tele-manipulation has been demonstrated. The overall accuracy of the robot-based neurosurgery is tabulated. This approach eliminates line-of-sight issue and the requirement of an additional unit for neuro-registration. This minimizes the registration time and makes intraoperative registration feasible.