Back pain that travels down the leg is called radiculopathy. It is caused by pressure on the spinal nerve from a herniated disc. Chemicals released from the damaged disc can also irritate the nerve causing radiculopathy.
A common treatment for this problem is an epidural steroid injection. The surgeon applies the numbing agent and antiinflammatory directly on the inflamed nerve (or as close as possible).
In this study, surgeons show that fluoroscopy can be used to guide the needle for better accuracy. Fluoroscopy is a form of X-ray that allows the surgeon to view what’s inside the body. The images are downloaded to a computer and viewed on the computer screen.
Without imaging, there is a 25 to 30 per cent incidence of incorrect needle placement. In the lumbar spine, there is an increased risk of injecting a blood vessel without imaging. But with imaging, there is a risk of exposure to radiation.
In this study, surgeons perform L5 and S1 ESIs at the same time. Although they use fluoroscopy to guide both needles into the foramen, there is less radiation exposure. The foramen is the opening in the vertebral bone for the spinal cord or spinal nerves.
MRIs of the procedure are shown. The surgeons use a view and contrast dye that shows the Scotty dog formation. This is the outline of a Scotty dog formed (in part) by the pedicle of the vertebra.
The pedicle is the connecting bridge of bone between the main body of the vertebra and the posterior portion of the bone. The Scotty dog formation can only be seen when images are taken at an oblique angle. The pedicle forms the eye of the dog. Finding this image allows the surgeon to locate the foramen.
The authors conclude using fluoroscopy to view the S1 foramen can improve accuracy and effectiveness of ESI at the L5 and S1 levels. Further studies are needed to measure the actual amount of radiation exposure.