Using Injections for Back Pain
When back pain isn’t being effectively managed with medications and physical therapy alone, patients often explore other forms of pain management before considering surgery. Usually consisting on a steroid medication and a local anesthetic, injections are a non-surgical form of pain management placed directly into the affected area. Depending on the type of injection given and the specific condition being treated, relief can last anywhere from several weeks to a year or more.
Conditions Managed with Injections
Injections are primarily used to treat back pain due to nerve damage or spinal stenosis, a narrowing of the spaces within the spine. Radiating nerve pain (radiculopathy) due to nerve damage is often felt in the buttocks, hips, or legs; or patients may experience shooting pain that goes from the lower back to parts of the leg. The most common form of nerve pain related to the spine is sciatica, which affects the longest nerve in the human body (the sciatic nerve) that runs from the lower back to the legs. The neck, shoulders, and arms may be affected if nerve compression is in the thoracic (upper) or cervical (neck) spine. Injections may provide relief for nerve pain related to:
- Disc herniation
- Degenerative disc disease
- Slipped disc (spondylolisthesis)
How Injections Work
A diagnostic injection with a short-acting anesthetic may be given before an injection is used for pain management to determine if the nerve suspected of being the one causing the discomfort is the correct nerve. Injections are typically delivered with x-ray guidance to ensure that the correct nerve is selected. A local anesthetic (lidocaine or bupivacaine), eases pain from the injection itself. Inflammation, a typical contributing factor to nerve pain, is reduced with a steroid medication, usually cortisone, methylprednisolone acetate, triamcinolone acetonide, or dexamethasone. Saline is sometimes used a “flushing agent” to remove inflammation-causing proteins.
Types of Injections
Inserted into a sac cradling the nerve root, epidural injections provide temporary relief for about half of all patients with lower back pain who opt for this treatment. In addition to being used to isolate a nerve causing back pain that can’t be clearly identified on an MRI, selective nerve root blocks (SNRB) may also be used to “block” pain signals and provide relief. Facet blocks are placed into facet joints, which may be affected by facet joint syndrome, in the spine with the guidance of a live x-ray (fluoroscopy).
Potential Side Effects
Side effects associated with injections are often mild in nature. Infection in the dural space may occur, but this is rare. There may temporary irritation at the injection site that goes away within a few days. Also considered rare, a cerebrospinal fluid leak, referred to a “wet tap” is a risk specifically associated with epidural injections. With selective nerve root blocks, leg pain may temporarily worsen since the injection is placed next to a nerve root.
Injections may provide enough pain relief to allow patients to actively participate in physical therapy and rehabilitation exercises without distracting pain to strengthen back-supporting muscles. While often an effective form of pain management, injections do not address the actual source of back pain. However, patients may regain enough muscle strength over time so their pain can be effectively managed once the effects of the injection wear off.