A System for Microscope-Assisted Guided Interventions

Abstract

We present a system for surgical navigation using stereo overlays in the operating microscope aligned to the operative scene. This augmented reality system provides 3D information about nearby structures and offers a significant advancement over pointer-based guidance, which provides only the location of one point and requires the surgeon to look away from the operative scene. With a previous version of this system, we demonstrated feasibility, but it became clear that to achieve convincing guidance through the magnified microscope view, a very high alignment accuracy was required. We have made progress with several aspects of the system, including automated calibration, error simulation, bone-implanted fiducials and a dental attachment for tracking. We have performed experiments to establish the visual display parameters required to perceive overlaid structures beneath the operative surface. Easy perception of real and virtual structures with the correct transparency has been demonstrated in a laboratory and through the microscope. The result is a system with a predicted accuracy of 0.9 mm and phantom errors of 0.5 mm. In clinical practice errors are 0.5–1.5 mm, rising to 2–4 mm when brain deformation occurs.

Depth Perception – A Major Issue in Medical AR: Evaluation Study by Twenty Surgeons

“…The task and the visualization modes can be viewed in the video 1 . The task consists of a pointer that has to be moved to a spot inside a body phantom.…”

“…The idea of in-situ visualization for surgical procedures has been widely discussed in the community [1,2,3,4]. While the tracking technology offers nowadays a sufficient accuracy and visualization devices have been developed that fit seamlessly into the operational workflow [1,3], one crucial problem remains, which has been discussed already in the first paper on medical augmented reality [4]. Even though the data is presented at the correct place, the physician often perceives the spatial position of the visualization to be closer or further because of virtual/real overlay.…”

Hybrid Navigation Interface for Orthopedic and Trauma Surgery

“…Most methods described in literature use tracked pointers to register markers in patient space with their corresponding centroids segmented from imaging data [1]. We designed markers that are automatically detectable both in the imaging data and in the physical space.…”

“…In the past decade numerous applications and hardware setups using augmented reality visualization in medical navigation were proposed. King, Edwards et al [1] developed a stereoscopic system called MAGI that is used for microscope based neurosurgery. Birkfellner et al [2] designed and developed the VarioscopeAR, an augmented reality head mounted operation microscope, for maxillofacial surgery.…”

Camera Augmented Mobile C-Arm (CAMC): Calibration, Accuracy Study, and Clinical Applications

“…Exemplary setups and applications for in situ visualization include augmented reality operating microscopes for neurosurgery [21], [22], head mounted operating binoculars for maxillofacial surgery [23], augmentation of magnetic resonance imaging (MRI) data onto an external camera view for neurosurgery [24], and systems based on head mounted displays [25]- [28]. A system based on a tracked semi-transparent display for in situ augmentation has also been proposed [29].…”