Epidural Injections
An Epidural injection is perhaps the single most useful intervention available in the modern interventional pain clinic. Epidural therapy is effective in the treatment of many painful conditions including intervertebral disc injury, acute herpes zoster, post-herpetic neuralgia, reflex sympathetic dystrophy, radicular pain in pregnancy, cancer pain, and post-surgical pain. It is also used as an adjunct to noninvasive therapy and may allow the patient to participate more fully in physical therapies and comprehensive rehabilitation programs.
Inflammation as a Source of Pain
New research has identified inflammation within and around neural structures as a common occurrence in painful conditions. Neural inflammation has been shown to facilitate pain processing and increase firing of pain neurons within ganglia, nerve roots, and the spinal cord, and it is thought to be instrumental in the development and perpetuation of many types of persistent pain. Epidural injection is a safe and effective method to “put out the fire” of inflammation.
Epidural Injections Deliver Medication
The epidural space allows unique access to the spinal cord and nerve roots at every level of the spine. Epidural injections provide a safe, low-risk, nearly painless means of delivering a variety of medications directly to the nervous system. Medications used alone or in combination include steroids, local anesthetics, and opioids. Once delivered into the epidural space, these medications may block pain impulses, stabilize irritated nerve structures, reduce inflammation and swelling, and reverse the biochemical changes that are known to occur within the nervous system when pain persists.
Disc Herniation and Inflammation
The process of intervertebral disc herniation is a prime example of an acute process often associated with spinal inflammation and severe persistent pain. Outward movement of the caustic disc nucleus causes inflammation and swelling to occur within the confined spaces of the spinal column, and may cause sensitization and compression of the spinal cord and nerve roots, resulting in severe radicular pain. Irritated nerve roots in turn send signals to muscles which then may spasm. When pressure is increasingly intense, sensorimotor changes may occur. Disc herniation and secondary spinal inflammation do not usually cause nerve damage, thus early surgical intervention is often not indicated. Since herniated disc material may be resorbed over time by the body without surgery and since surgery cannot “cure” the underlying problem of disc degeneration, it is usually wise to consider surgical intervention only after conservative care fails.
An Extension of Conservative Care
Epidural steroid and local anesthetic injection may effectively decompress the spinal area, reverse inflammation, and relieve symptoms without surgery while the body resorbs herniated disc material over time. Since persistent inflammation may cause pressure damage to nerves and result in fibrosis and the formation of scar tissue within the spinal column, reversal of inflammation should be a prime goal of therapy. Spinal injection is considered an extension of conservative care by many spine specialists and is typically performed in a series of three injections at two-week intervals if symptoms are persisting.