Spinal injections can be an effective nonsurgical treatment for people whose back pain does not improve with medication or physical therapy. In addition, spinal injections are sometimes used in the diagnosis of low back pain. When used for diagnosis, specific areas of the back are temporarily numbed with injections of lidocaine, a local anesthetic. If the patient feels relief, the numbed area is assumed to be the source of the back pain.
How Injections Work
When used for back pain relief, spinal injections contain corticosteroids to reduce inflammation, local anesthetics to relieve pain, or a combination of corticosteroids and anesthetics. In the short term, spinal injections can be more effective than oral medication because the injected medication is concentrated in the affected area.
But there is no strong evidence that spinal injections offer long-term pain relief. In addition, spinal injections do not resolve the underlying back problem. However, they can reduce back pain temporarily so patients can participate in physical therapy or engage in other exercises to strengthen and stretch the back.
If you experience no relief from a spinal injection, a second injection likely will not be successful, either; however, if the first injection is helpful, another injection two weeks later may be recommended. More than three corticosteroid injections per year are not recommended, however, because of potential side effects from the steroids.
Spinal injections are done as an outpatient procedure and are relatively safe, as long as they are administered infrequently. Serious events such as infection or bleeding are rare.
Possible side effects from the corticosteroids themselves, although much less common than in people taking daily doses of steroids, include temporarily impaired immunity, high blood glucose levels, stomach ulcers, cataracts, and increased appetite. Some people may experience allergic reactions to a solvent used in the injected fluid.
Spinal injections are not recommended for people who have a bacterial infection or whose back pain is caused by a tumor or infection; caution is needed when performing injections in people who have heart failure or diabetes or are taking aspirin or other antiplatelet drugs because of the risk of bleeding.
The types of spinal injections used to try to relieve back pain vary, depending on the medication used and the area of the spine targeted for treatment.
Epidural Corticosteroid Injections for Back Pain
An epidural injection of a corticosteroid may reduce inflammation around a herniated disk that is causing leg or low back pain. The medication, injected into the epidural space (the area between the spinal cord and the vertebrae), reduces the production of substances that cause inflammation.
Epidural corticosteroid injections provide relief for about half of patients—pain relief can last for as little as one week or for as long as one year. The injections may be particularly helpful for people with acute leg or low back pain who are experiencing a severe episode that has not responded to other nonsurgical treatments. These injections are not valuable for chronic problems.
Selective Nerve Root Blocks for Back Pain
Selective nerve root blocks are used to identify and treat compressed and inflamed spinal nerve roots that are causing leg or back pain. The injections usually consist of a local anesthetic—either alone or in combination with a corticosteroid—and are introduced next to the nerve root where it exits the spine. The anesthetic provides temporary pain relief, while the steroid reduces inflammation around the nerve root.
Success rates for this procedure vary, but a small study recently found that patients who received an injection of anesthetic had no more pain relief or lower medication use than patients who had no injections.
Facet Joint Injections for Back Pain
The facet joints are where the spinal processes from adjacent vertebrae meet at the back of the spine. Inflammation, irritation, or swelling in a facet joint may cause low back pain. Injections of a local anesthetic, corticosteroid, or both into a facet joint are used primarily for diagnosis, but they can also treat back pain caused by a problem in the facet joint.
Whether facet joint injections are helpful is controversial; in a 2002 study of 230 people with low back pain, an injection relieved back pain in only half of the patients over a 10-month period. Facet joint injections are not helpful for chronic problems.
Another Option: Muscle Injections for Back Pain
Trigger point injections are an option for back pain caused by muscle problems. In addition, botulinum toxin (Botox) is being studied as a potential treatment for back pain due to muscle problems.
-
Trigger Point Injections. Trigger points are bunches or “knots” of muscle tissue that do not relax. These knots often entrap surrounding nerves and cause pain in various areas of the body, including the back and neck. Muscle strain, herniated disks, pinched nerves, and fractures all may cause trigger points. Injecting an anesthetic into a trigger point may reduce pain by helping to relieve the muscle spasm, but few studies have evaluated the use of trigger point injections to treat low back pain.
-
Botox. A few small studies have suggested that Botox, first used in children with cerebral palsy and now commonly used to temporarily relax facial muscles that contribute to wrinkles, may also be helpful in treating some forms of back pain. For example, one randomized study of 31 people with chronic low back pain found that those who received Botox injections were more likely to have back pain relief over an eight-week period than those who received saline injections. No side effects were experienced in either group.
Botox is only helpful for back pain caused by muscular problems, such as trigger points. It is thought to relieve pain by partially paralyzing the muscle and causing it to relax. Although Botox is quite safe when injected, it can cause temporary muscle weakness. Larger studies are needed to determine whether Botox is more effective than injections of traditional pain-relieving medications. Its effectiveness for spinal problems caused by spinal degeneration is very controversial. Botox should not be used frequently, as repeated injections can cause permanent muscle damage.
For more Back Pain and Osteoporosis articles,
please visit the
Back Pain and Osteoporosis Topic Page
