FluoroNav: Virtual Fluoroscopy System
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.
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.
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.