Lumbar nerve root blocks have become a very popular treatment for back and leg pain that doesn't respond to pain relievers or physical therapy. A steroid mixed with a numbing agent like novacaine is injected as close to the nerve root as possible.

The idea is to decrease the chemical irritation of the nerve from the disc. Studies show that degenerated vertebral discs have enzymes that release chemicals. An inflammatory response is set up and pain is the result. Usually only one injection is needed for pain relief. Sometimes a second or third injection is required before the patient gets the desired results.

In a small number of patients (five percent) new pain or leg numbness or weakness occurs with nerve root blocks. They may have some lightheadedness. These minor problems are temporary. More serious problems are less common but can happen. Paralysis, headache, and increased pain are some of the major complications reported.

Most patients report immediate improvement or pain relief within the first 24 hours.