Contrast is used to verify epidural location and to indicate the distribution of injectate. Some physicians use contrast as a volume expander while others prefer saline for this use. The contrast is typically nonionic and lowosmolar. In patients with contrast allergies gadolinium can be safely used in most lumbar procedures. 30,31,52,53 If using gadolinium, the amount should be just enough to document epidural injection. Gadolinium should not be used as a substitute for volume expander. The typical amount of contrast or contrastsaline mixture used for either cervical or lumbar interlaminar epidurography is 4 cc to 5 cc (less in nerve blocks; see below). A smaller amount will not provide sufficient contrast for an epidurogram to evaluate for adhesions or distribution of injectate. For coding purposes, an epidurogram is considered to have been performed when approximately 4 cc to 5 cc of contrast is injected regardless of the route (transforaminal or interlaminar). The report, CPT code, and amount billed must be adjusted if an epidurogram is not performed. The amount of contrast injected may be reduced in spinal stenosis. Many patients will feel pressure or leg cramping from almost any volume, no matter how small. Patients undergoing first-time injections may confuse this with pain. Careful questioning and reassurance that pressure is normal will be adequate in most cases. The injectate volume should be reduced if significant pain is experienced.
With the disc nucleus replacement only the central portion of the disc (nucleus) is removed and replaced with mechanical device, while the outer ring of the disc (annulus) is not removed. However disc nucleus replacement procedure is not commonly practiced and is in investigative stage. In total artificial disk replacement, the annulus and nucleus are replaced with the mechanical device to restore normal spinal function. Artificial discs are usually made up of metal, plastic or a combination of metal and plastic. Medical grade plastic (polyethylene) and medical grade cobalt chromium or titanium alloy are used for disk design.
The needle is smaller in size than that used during a conventional epidural approach. The procedure is performed with the patient lying on their belly using fluoroscopic (real-time x-ray) guidance, which helps to prevent damage to the nerve root. A radiopaque dye is injected to enhance the fluoroscopic images and to confirm that the needle is properly placed (See Figure 2). This technique allows the glucocorticoid medicine to be placed closer to the irritated nerve root than using conventional interlaminar epidural approach. The exposure to radiation is minimal.