Clinical Experience and Perception in Stereo Augmented Reality Surgical Navigation

Over the last 10 years only a small number of systems that provide stereo augmented reality for surgical guidance have been proposed and it has been rare for such devices to be evaluated in-theatre. Over the same period we have developed a system for microscope-assisted guided interventions (MAGI). This provides stereo augmented reality navigation for ENT and neurosurgery. The aim is to enable the surgeon to see virtual structures beneath the operative surface as though the tissue were transparent. During development the system MAGI has undergone regular evaluation in the operating room. This experience has provided valuable feedback for system development as well as insight into the clinical effectiveness of AR. As a result of early difficulties encountered, a parallel project was set up in a laboratory setting to establish the accuracy of depth perception in stereo AR. An interesting anomaly was found when the virtual object is placed 0-40mm below the real surface. Despite this such errors are small (~3mm) and the intraoperative evaluation has established that AR surgical guidance can be clinically effective. Of the 17 cases described here confidence was increased in 3 cases and in a further 2 operations patient outcome was judged to have been improved. Additionally, intuitive and easy craniotomy navigation was achieved even in two cases where registration errors were quite high. These results suggest that stereo AR should have a role in the future of surgical navigation.