NERVE BLOCKS: Part I

After last month’s Pain Update about epidurals, I received several questions about what blocks we do and why we do them. I will provide you with a two part synopsis. If your group would like me to present a slide show talk, A Guided Tour of Nerve Blocks, please email me at the address below, or telephone 310-829-8080.

What are blocks?
Blocks are injections of medication onto or near nerves. The medications that are injected include local anesthetics, steroids, and opioids. In some cases of severe pain it is even necessary to destroy a nerve with injections of phenol, pure ethanol, or by using needles that freeze or heat the nerves. Injections into joints are also referred to as blocks. Although not technically correct, such “shorthand” is commonly used.

Why do we do blocks?

Remember, blocks are not the best treatment for all pain problems. Patients often ask me, “Doc, can’t you just do a nerve block?” Often blocks are not possible, are too dangerous, or simply are not the best treatment for the problem.

Spinal Injections:
The most common spinal injection is the lumbar epidural steroid injection. This is particularly useful for pain that radiates from the lower back into a leg, and is caused by disc herniation or spinal stenosis (narrowing around the nerves) which triggers nerve root irritation. Similar injections can be very useful in the cervical spine, where the symptoms will extend into the arms. Thoracic epidural steroid injections are most commonly used to reduce the pain associated with herpes zoster (shingles). Such blocks may reduce the risk of developing persistent postherpetic neuralgia (i.e., pain which persists long after the skin eruption has healed).

The facet joints of the spine can also cause pain. Injections into the facet joints or blocks of the nerves that go to the facets can often be very helpful with these pains. This problem is more common in the lumbar spine, but also occurs in the neck.

Discograms (intradiscal injections of contrast under fluoroscopy or CT imaging) can determine if and which disc is the source of the pain. This can help a surgeon determine which levels of the spine require surgery. If the patient is found to have a painful disc, they may be a candidate for a new and promising technique, intradiscal electrothermoplasty (IDET). In a procedure similar to a discogram, a wire is temporarily inserted into the disc and used to heat the disc. This destroys the invading sensory nerves and causes the proteins of the disc wall to reshape and slowly strengthen (over 3-6 months). The procedure cannot be done if the disc has already severely degenerated.

Next time, I will continue with Part II, when we will look at:

Until then… Steven Richeimer, M.D.

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