The selection of injection technique is most often determined by the location of the pain and the most likely structure(s) involved. Common sources of pain are nerve root pain, joint pain, muscle pain, or a combination of any of the above.
Some of the most common spinal interventions are as follows:
1. Epidural steroid injections (ESI)
ESI’s treat pain caused by inflamed spinal nerves. Success rates vary:
- Symptoms present for less than 3 months: 90% successful.
- Symptoms present for approximately 6 months: 70% successful.
- Symptoms present for 1 year: 50% successful.
Benefits tend to be temporary, ranging from several weeks to years. Improvements are noticed within 3-10 days after the injection.
Patients generally require 1-2 injections for maximum benefit and are best performed in conjunction with the start of a physical therapy and/or home exercise program.
2. Facet joint injections
These are used to diagnose and/or temporarily relieve neck or back pain caused by inflamed facet joints, the area where two vertebrae meet in the spine. Benefits tend to be temporary, ranging from several days to years. About 50% of patients experience some degree of pain relief.
If prior injections are helpful but the pain returns, facet joint injections can be repeated up to 3 times a year. If there was no pain relief after the first injection, further injections would not be helpful.
3. Medial branch nerve block injections
These injections also treat or diagnose pain arising from the facet joints of the spine. Local anesthetic is injected into the medial branch nerves, the small nerves that control feeling in the facet joint. Results are usually noticeable 10-20 minutes after the injection. If there is at least 70% pain relief, more injections may be recommended.
With medial branch nerve block injections, if the pain goes away initially but later returns, a radiofrequency neurotomy may be a more appropriate treatment option.
4. Radiofrequency neurotomy
This procedure uses heat producing radio waves to destroy medial branch nerves, disrupting pain signals to the brain caused by facet joints. It is normally recommended after a medial branch nerve block was successful.
Average pain relief has been shown to last 10½ months and success rates are about 85%. The degree of pain relief varies from person to person, and may take up to 3 weeks before maximum pain relief is evident.
The procedure may be repeated as long as the pain relief lasts longer than 6 months each time.
5. Sacroiliac (SI) joint injections
SI joint injections are commonly used as a diagnostic tool to determine the cause of a patient’s low back pain. The SI joint is injected with a local anesthetic and cortisone to numb the area. If the SI joint is the source of the pain, the injection will temporarily eliminate the patient’s pain.
If the SI joint is confirmed as the structural source of pain, exploring options for treatment may be more successful.