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Virtual
reality has just hit the operating room with a totally new
fluoroscopic system called FluoroNav. To appreciate FluoroNav,
take a step back to basic Fluoroscopy 101.
Fluoroscopy
101
In
fluoroscopy, a medical device called a fluoroscope (sometimes
termed a C-arm because of the shape of the device) takes
an x-ray of a patient and displays it on a viewing screen,
much like a TV. Spine surgeons often use this device to
help them locate structures within the spine and to help
guide the placement of spinal instrumentation, such as pedicle
screws. It is one of the oldest forms of diagnostic radiology
used to examine the inner body. Every time the surgeon wants
to see a new view of the spine (as an instrument is inserted
into it, for example), he/she must take another x-ray. If
the surgeon wants to see a view of the spine from another
angle, the C-arm must be moved to that new angle and then
another x-ray must be taken. Each new view exposes the patient
and the surgical team to more radiation.
Now
enter FluoroNav, a navigational (surgical guidance) system
that combines a conventional C-arm fluoroscope with a surgical
computer. By harnessing the power of the computer with the
fluoroscope, FluoroNav allows the surgeon to see many views
of the spine from many different angles simultaneously,
all with minimal x-ray exposure.
FluoroNav
works with pre-acquired fluoroscopic views. In other words,
the surgeon takes pictures of the spine with the fluoroscope
while the patient is in the operating room, but prior to
navigating in the spine. These pictures are stored in the
surgical computer. The computer then tracks a surgical instrument
in the operating room using a special camera that can "see"
the precise position of the instrument using harmless infrared
light (like the light that a TV remote control uses to change
the channel). The computer plots the location of the instrument
on the spine pictures that it has "remembered." As the position
of the instrument changes (when the surgeon inserts it into
the spine, for example), the computer display shows this
new position. All of this is done without any additional
x-rays! This is very much like the new computer programs
that show the position of your car on a map as you drive
by tracking your car with the GPS (Global Positioning Satellite)
system. The location of your car is plotted on the computerized
map; as you drive, the picture of your car moves on the
map.
That's
enough about the technical details! The result is that FluoroNav
gives your surgeon very precise information about the position
of an instrument in your spine, just like the GPS system
can show you where your car is and help you avoid getting
lost. In fact, the FluoroNav system can "see" your spine
and a surgical instrument even through the skin. This allows
surgeons to perform minimally invasive spine surgery with
very precise guidance. The picture below shows the FluoroNav
system being used to place percutaneous (through the skin)
screws into the spine.
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Another
advantage of FluoroNav over conventional fluoroscopy is
that it can track a surgical instrument on multiple views
of the spine simultaneously. To do this with standard fluoroscopy,
a different C-arm has to be used for each view. In reality,
it is only practical to use two C-arms at any given time,
and even this is tedious to set up and clutters the operating
room. With FluoroNav, a single C-arm can be used to track
up to FOUR different views of a surgical instrument at the
same time. This additional information can add to the safety
of a surgical procedure, such as spinal screw placement.
Minimally
invasive spinal procedures are becoming more common in the
21st century. FluoroNav meets the challenges of these new
procedures, providing critical information to the surgeon
regarding the location of instruments inside the human body.
In addition, even for standard spine surgeries, FluoroNav
significantly reduces the amount of radiation that the patient
and the surgical team are exposed to. Thus, it represents
an important advance in image-guided spinal surgery.
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