Fluoroscopy is a digital X-ray that is ‘real-time’. A C-arm is an X-ray machine that can change orientation so several views can be obtained. This allows for precise needle placement for stem cell therapy injections. A C-arm can produce still images, but it also can produce live video.
This is excellent for both evaluation of a patient’s movements but it also allows for viewing “dye spread patterns” to ensure we are precisely injecting the target tissues. Without argument, fluoroscopy is the gold standard for orthopedic injections and is of great value with stem cell therapy.
HOW IT WORKS
Typically, the doctor first positions the C-arm for the optimal view of the structure to be injected. After cleaning the skin, a sterile, blunt, metal instrument is placed on the skin over the structure to be injected. This instrument shows up very clearly and allows the doctor to know the exact location of the structure of interest. When the instrument is exactly over the structure of interest, the doctor marks the skin with a sterile surgical marker. The skin is numbed with a tiny needle, and then the normal needle is introduced into the skin.
Still images are taken in order to get the tip of the needle in exactly the correct location. For many but not all injections, the doctor first injects “contrast”, or “dye” in order to verify that the tip of the needle is not lodged in a structure that cannot be seen on X-ray. The most commonly used contrast is a non-ionic iodine compound. It is completely inert and safe , especially at the tiny volumes we use. The huge advantage of using contrast is this is the only way to be 100% certain that the stem cells are coming into contact with the target tissue.
When injecting a knee, even though the tip of a needle is in the exact center of the joint, it entirely possible that it is lodged in a fat pad, one of the cruciate ligaments, or even in a blood vessel. The doctor holds down the image taking peddle in order to put the C-arm in video mode, and then watches the ‘spread pattern’ of the contrast. If the contrast flows into the joint, it immediately spreads through the entire joint. If the tip of the needle is in a fat pad, it creates something that looks like a black cotton ball. If it is in a cruciate ligament, the black compound takes the shape of the ligament. If it is in a blood vessel, then it very quickly spreads through the vessels.