Accuracy Evaluation of Image-Based Virtual Fixtures in Robotic Laminectomy

The accuracy of image-based computer assisted orthopedic surgery highly depends on the accuracy of the registration step as well as image acquisition, planning and tool calibration. In this paper the accuracy of those steps is evaluated exemplarily for a robotic laminectomy.A high-resolution test bench was designed to compare the actual location of an object and the position to which the robotic system guides the surgical tool according to the image-based plan.Depending on the distance between the patient reference array and the tool array, average accuracies from 0.14 mm ± 0.17 mm to 0.42 mm ± 0.15 mm with a maximum error of 0.59 mm were measured.This very high accuracy is in the range of the thickness of the spinal dura mater.