Robotic neurological surgery applications: accuracy and consistency or pure fantasy?

Abstract

Introduction: Minimally invasive surgery was born out of recent advances in neuroimaging and stereotaxy, and the scale of future neurosurgical procedures will soon be so small that it will not be possible for the unassisted surgeons. Hence, neurosurgical robotics is a natural evolution in this field. The aim of this study was to evaluate the performance of a new robotic system in a wide range of neurosurgical applications.

Methods: Patients undergoing image-guided surgical procedures were recruited to participate in this prospective ethically approved study from 2005. The PathFinder (Prosurgics, UK) is a neurosurgical robotic system with 6 degrees of freedom. It uses a fiducial system that is automatically detectable by the planning software and a camera system embedded in the robot's head. The registration procedure was performed automatically by photographing the fiducials from different angles. The robot then aligns its end-effector and tool holder along the specified path for the surgeon to pass the probe to the target. We recruited 37 consecutive patients to test the application accuracy and consistency of the system using three different fiducial fixation mechanisms: a double adhesive fixed to the skin, an ECG lead dot fixed to the skin, and a registration plate fixed to the skull.

Results: Out of 37 consecutive patients, 17 were males and 20 were females, with a mean age of 46.6 years. The procedures were: transsphenoidal in 8, malignant tumour biopsies in 3 and resections in 5, benign tumour excisions in 6 and functional procedures in 15 [6 bilateral deep-brain stimulations (DBSs) of the subthalamic nucleus for Parkinson's disease, 3 bilateral anterior cingulotomies for depression, 3 bilateral DBSs of the ventral intermediate nucleus of the thalamus for tremor and 3 depth electrodes during epilepsy surgery]. We tested a total of 140 targets with an average of 3-4 targets per patient. The mean application accuracy was less than 1 mm and the application accuracy was consistent in all targets in the same patient.

Conclusions: This robotic system was very accurate and consistent in practice as long as the robot had achieved acceptable registration.