The Guide to Augmented Reality in Microsurgery

In the medical field, several tools are used for pre-operative investigations, including imaging techniques such as CT-scan, MRI, angiography, ultrasound, or transcranial magnetic stimulation. All this information can supplement a surgical procedure via 3D imaging technology. Surgeons can visualize the operating field with AR information on 3D visualization viewing systems such as 3D monitors or headsets. There is also a wide range of surgical visualization tools. 

Operating microscopes, for example, provide magnification but also support fluorescence imaging (for example with 5-ALA), neuro-monitoring, neuro-mapping, neuro-navigation, and offer a Mixed Reality navigation viewing experience. The surgeon can access the operating field and AR overlays in a digitally enhanced live image, displayed on a monitor or a digital headset.

During the Leica Neurosurgical Visualization summit, Dr Raphael Guzman, Professor of Neurosurgery at the University of Basel in Switzerland, and Chair of the Department of Neurosurgery, spoke about fluorescence-guided neurosurgery and videoangiography. 

Overcoming the limitations of Indocyanine Green (ICG), the GLOW800 AR fluorescence application from Leica Microsystems, provides augmented information in the surgical field, allowing anatomy assessment and perfusion of blood vessels. GLOW800 AR combines the white light image with real-time fluorescence imaging in a digitally processed image superimposed on the blood vessels.

The GLOW400 AR fluorescence application for brain tumor surgery is taking visualization of suspected grade III and IV gliomas to another level. With advanced multispectral imaging from Leica Microsystems, GLOW400 offers multiple views that transform tumor visualization, helping surgeons stay focused and able to make more confident surgical decisions.

• The Anatomy view of GLOW400 combines information from fluorescent and non-fluorescent tissues as well as anatomical structures—all in a single real time image. This enhanced visualization of the fluorescence-marked tumor gives a clear view of the surrounding anatomical details. Thanks to this augmented view in 3D, surgeons no longer need to recall the differences between the white light image and FL400, which may reduce fatigue and minimize surgical interruptions.
• When it comes to low-intensity fluorescence signals, the GLOW400 Highlighted Fluorescence (HiFluo) view enhances visualization of suspected grade III and IV glioma tissue, by displaying a broader range of fluorescence intensities that may have previously been missed. This view allows surgeons to repeatedly check for remaining fluorescence signals. 

During oncological reconstructive surgery procedures, AR can help surgeons to accomplish the following:

• Confirm the viability of the flap with indocyanine green (ICG)
• Identify the viable mastectomy skin, as well as the nonviable skin and tissue.
• Increase the precision of the flap delimitation
• Avoid complications, such as fat necrosis

During surgery, surgeons need to check multiple monitors to get information from different sources. With the use of AR, access to the information becomes easier, preventing the interruption of the surgical workflow.

During aneurysm surgery for example, the GLOW800 AR fluorescence application allows surgeons to verify, in real-time, that all branches are open and perfused while the aneurysm is excluded from the circulation thanks to the GLOW AR view, showing green fluorescence in the blood vessels in a natural white light view of the cerebral anatomy.

By having that one single image, surgeons no longer need to look at different screens to get a read on the surgical area, allowing them to work uninterrupted.