The current standard in ENT navigation systems merges the pre-op
CT scan with the location of instruments as the surgeon moves them
through the surgical pathway. AR takes this approach a step further
by merging the location of the instruments with the view through the
surgeon's endoscope.
Distances to important structures are indicated right on the video
monitor that is displaying the endoscopic view of surgery, so the sur-
geon can refer to the information without looking away from the
action or switching between the CT scan and his camera view.
Critical anatomy that surgeons want to avoid like the optic nerve
can be marked ahead of time and are then overlaid onto the camera
view with their distances from the instruments updated in real time
during surgery. Surgeons can also mark pathways to target sinuses
and emphasize the anatomy around those pathways, adds Dr. Citardi.
This new system also lets the surgeon come up with a plan for the
surgery before entering the OR. Using the CT scan, he can plot a sur-
gical pathway and load it into the computer. Then during surgery,
the pre-determined pathway shows up on the camera view as differ-
ent colored rings. As an instrument moves inside the patient, it
shows up in real time on the CT scan and lights up the rings as it
"passes through" them.
Having the planned path and distances between the instrument and
important anatomical structures marked and displayed on the surgeon's
view is what makes AR an exciting advancement in ENT image guid-
ance. "Even with traditional navigation systems, the surgeon must look
at the navigation screen for positional information and the surgical field
separately," says Dr. Citardi. "With AR, that information is unified into a
single view, which could lead to faster and safer surgeries."
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