Types of injections
Injections are broadly grouped by the type of tissue or the location they are designed to treat.
Joint injections are used to relieve pain related to bursitis—an inflammation of a fluid filled sac that acts as a kind of shock absorber around a joint. There are two other kinds of joint injections: facet joint and sacroiliac joint injections. Facet joints are located between the vertebrae in the spinal column, and the sacroiliac joint is located in the very low back where end of the spinal column joins with the pelvis. There are tissues and nerves in these joints that can become inflamed due to injury or degenerative changes (arthritis), and injections can help relieve that pain.
Epidural injections are used for pain usually associated with problems in the spine. The doctor places medication near the spinal column where the nerve roots are located to relieve pain in the neck, shoulders, back or legs. Epidural injections are used for such conditions as spinal stenosis, herniated disc, or degenerative disc disease (arthritis).
Nerve blocks are used to help diagnose the underlying cause of neck or back pain. The doctor places medication where he believes the pain is coming from, and if it is relieved he then knows he has located the source of the pain. This is sometimes necessary because pain is often referred from its actual source to other areas of the body, making it difficult to always know with precision where it is coming from.
Trigger points are used to treat small, localized contractions in muscle tissue that can produce a wide band of pain, often in the back or shoulders. These small contractions pull on the tendons and ligaments associated with the muscle resulting in pain in distant areas not immediately associated with that muscle.
The doctor normally combines two medications in these injections: a local anesthetic and a steroid. The local anesthetic often provides almost immediate relief but it is short acting; the steroid acts more slowly but provides much longer lasting relief. Once the local anesthetic wears off (3-12 hours), your pain will return or even get a little worse at first. This is normal and expected. Once the steroid is fully absorbed and begins to reduce the swelling and inflammation that is contributing to your pain, your pain will start to subside.
Treatment usually consists of a series of three injections over a period of about six weeks, depending on the underlying condition and the patient’s response to treatment. Injections using steroids are generally limited to about three in a six month period to minimize any potential side effects of the medication.
Injections performed under X-ray guidance by an experienced physician are extremely safe. Potential complications, including infections, bleeding, nerve injury or headache could happen but they are highly unlikely.
There are no known long term side effects from a series of injections, but if you are diabetic your blood sugar level may rise for several days to a week after the injection. Diabetics should take precautions to ensure their blood sugar is well controlled before getting a pain injection.