Radiculopathy: steroid epidural

Background

Radicular pain is sharp, lancinating, radiating pain, often shooting from the low back down into the lower extremity in a radicular distribution. It is the result of a nerve root lesion or of inflammation. Clinically, it can be associated with pain, dermatomal hypesthesia, weakness of muscle groups innervated by the involved nerve roots, diminished deep tendon reflexes, and positive straight-leg raising tests. Inflammation at the epidural space and nerve roots provoked by a herniated disk is a significant factor in causing radicular pain. Other mechanisms include compression of the nerve root vasculature and irritation of dorsal root ganglia from spinal stenosis.

Epidural steroid injections (ESIs) can deliver steroids in a more localized fashion to the area of affected nerve roots, thereby decreasing the systemic effect of the administered steroids. ESIs can be both therapeutic and diagnostic. Diagnostically, ESIs help to identify the region of pain generation through pain relief after local anesthetic injection to the site of presumed pathology, and if the patient experiences more prolonged pain relief, it can be assumed that an element of inflammation was involved. This more prolonged pain relief is presumed to result from a reduction in an inflammatory process, during which time one can also presume that the nerve roots are relatively protected from the effects of inflammation.

Indications for ESIs

Lumbar: lumbosacral disk herniation (the primary indication), spinal stenosis with radicular pain (central canal stenosis, foraminal and lateral recess stenosis), compression fracture with radicular pain, facet or nerve root cyst with radicular pain Cervical: pain associated with acute disk herniation and radiculopathy, postlaminectomy cervical pain, cervical strain syndromes with associated myofascial pain, postherpetic neuralgia Thoracic: acute disk pathology, postherpetic neuralgia, trauma, diabetic neuropathy, degenerative scoliosis, compression fracture

Contraindications

Absolute contraindications

➢ systemic infection or local infection at the site of planned injection

➢ bleeding disorder or fully anticoagulated

➢ history of significant allergic reaction to injected solutions (contrast, local anesthetic, steroid)

➢ acute spinal cord compression

➢ patient refusal

Caution with

➢ pregnant patients (due to fluoroscopy used for procedure)

➢ patients with poorly controlled diabetes (steroids may increase blood glucose levels)

➢ patients with a history of immunosuppression

➢ patients with congestive heart failure (due to the risk of fluid retention due to steroids)

Efficacy

Studies have shown a positive efficacy when lumbar ESIs are used for radiculopathy in well-selected patients in conjunction with fluoroscopic guidance and radiographic confirmation. Benefits include relief of radicular pain and LBP (with leg pain generally relieved more than back pain), facilitation of ability to participate in physical therapy, improvement in quality of life, reduction of analgesic consumption, and improvement in the maintenance of work status. Studies have also shown that ESIs are most effective in the presence of acute nerve root inflammation. In general, patients who have had symptoms for less than 3 months have response rates of 90%. When patients have had symptoms for less than 6 months, the response rate decreases to 70% and further to 50% when symptoms have gone on for over 1 year. Patients with symptoms of shorter duration have more sustained relief than those with chronic pain. Patients with chronic back pain will have a better response if they develop an acute radiculopathy. Favoring the use of ESIs: those who have not had previous back surgery, who are not on workers’ compensation, who are younger than 60, and who are nonsmokers.

Despite efficacy, patients must be educated that ESI alone may not be the only solution. It is just one of many non-operative methods to treat LBP and/or radicular symptoms. Other treatments may include short-term bed rest, medications (analgesics, muscle relaxants), physical therapy, and the management of any psychological, financial, marital, and work-related problems. The experts recommend ESIs be performed in combination with “a well-designed spinal rehabilitation program.”

Safety

Similar to other neuraxial anesthesia techniques

Most common risks

Backache, postural headache, nausea, vomiting, dizziness, and vasovagal reaction.

Rare, but serious

Bleeding along the trajectory of the injection, including epidural hematoma (0.01-0.02% of procedures); infection (more common in immunosuppressed patients) including epidural abscess formation and meningitis, nerve root injury, anterior cord syndrome, spinal cord trauma (cervical/thoracic injections, or compression from hematoma or abscess).