Restricted Surface Matching—Numerical Optimization and Technical Evaluation

Abstract

Accurate and reliable registration is one of the most important issues in computeraided surgery, as small errors may have a large influence on the overall accuracy of the system.The restricted surface-matching algorithm @!3lQ, initially developed for periacetabular osteotomy surgery (PAO), has been improved to become numerically more stable and reliable.To assess the accuracy and sensitivity of registration, a framework is presented that evaluates two aspects of registration the sensitivity and raw performance of the registration algorithm are tested in a stand-alone environment, and the integration into a CAS system is analyzed by evaluating the accuracy of the complete system.For the latter tests, spherical-headed titanium screws used as fiducial landmarks provide a reference transformation for the registration.This framework was used to analyze the performance of RSM for PA0 surgery.The sensitivity analysis showed the algorithm to be insensitive to noise up to a magnitude of 3 mm.Both the sensitivity analysis and simulated surgical environment tests showed that an accuracy can be attained of better than 2 mm in the region of interest, and better than 4 mm far away from the region of interest.This is sufficient for safely assisting P A 0 surgeries.