What is Epidural Steroid (cortisone) Injection ?

Epidural gluco-corticoid injections are commonly given to patients with leg and/or back pain to relieve such pain and improve mobility without surgery. These steroid injections buy time to allow healing to occur and/or as an attempt to avoid surgery after other conservative (non-surgical) treatment approaches have failed

During a trans-foraminal injection, a thin needle is inserted into the epidural space through the bony opening of vertebral column from where a nerve root exits. (See Figure 1, Neuroforamen). The drug is delivered exactly in the area where disc is compressing nerve and causing inflammation.

The procedure is performed with the patient lying on their belly using fluoroscopic (real-time x-ray) guidance, which helps to prevent damage to the nerve root. A radio-opaque dye is injected to enhance the fluoroscopic images and to confirm that the needle is properly placed (See Figure 2). This technique allows the cortisone medicine to be placed closer to the irritated nerve root. The exposure to radiation is minimal.

Indications include disc herniations, Lumbar canal stenosis, vertebral fractures, Cancer tumor compressing epidural space, Herpes zoster pain etc.

Patients with disc herniations and leg pain attains maximal improvement in 6 weeks. Interestingly, long-term success rates for trans-foraminal epidural glucocorticoid injections ranged from 71% to 84%.

Therapeutic Rationale – why steroids?

Structures (pain generators) like nerves/discs are accessible to neural blockade.
Surgery of these structure may fail to cure and may worsen painful spinal conditions.
Degenerative processes of the spine and the origin of spinal pain is complex.
The effectiveness of a large variety of therapeutic interventions used to manage chronic spinal pain has not been demonstrated conclusively.
There is increasing evidence supporting the use of interventional techniques in managing spinal pain

The objective

To deliver corticosteroid close to the site of pathology
Trans Foraminal Epidural Steroid Injection (TFESI) – more specific & targeted to site of pathology
Interlaminar injections are very effective in cervical (neck) area
Decrease size of disc means Decrease symptoms? It is not always the case, as compression may continue in spite of resolution of the symptom. In many cases MRI shows disc bulge but patients are pain free.
It is also well described in many studies that asymptomatic individuals present with disc herniations that are evident on CT / MRI scans

Multiple mechanisms to explain radicular pain

Nerve damage of various nature (Partial axonal damage, Neuroma formation, Focal demyelination, Intraneural edema), Impaired microcirculation, Chemical irritation, Inflammation. The Steroid acts to reverse all these.

Lumbar Epidural Steroid Injection

Cervical epidural injection

Selective nerve root block

A selective nerve root block (SNRB) is an injection that delivers medication into the space around spinal nerve roots. The goals of this treatment are to determine the location of a specific spinal nerve root that is the suspected cause of the pain and, secondarily, to provide relieve back, leg or other pain caused by the irritated spinal nerves. A SNRB may also be used therapeutically for the treatment of specific types of disc herniations

What to Expect During a Selective Nerve Root Block

An SNRB generally follows this process:

The patient lies face down on an x-ray table and the skin is well cleaned with an antiseptic.
The physician locates a specific spinal nerve root using fluoroscopy, a type of X-ray that provides real-time video imaging of your body.
Once the nerve root is located, the physician introduces a needle through the skin into the area adjacent to the spinal nerve
Medication — steroids (to decrease inflammation) and/or a local anesthetic (to numb the area) — is then injected into the area bathing the nerve root.
If the patient’s pain subsides after the injection, the pain-generating nerve root is presumed to have been identified.
The procedure normally takes 30 to 60 minute

What Causes Spinal Nerve Inflammation?

Spinal nerves can become inflamed due to compression, for example from a damaged disc or from contact with a bone spur. Depending on the location of the inflamed nerves, pain and/or other symptoms (such as numbness, tingling) may be experienced in different areas of the body. Nerve irritation in the cervical spine can cause pain, tingling or numbness in the neck, arm or shoulder. Nerve irritation in the thoracic spine can produce upper back pain or pain along the ribs and chest wall. Irritation of lower back (lumbar) nerves can produce lower back pain, hip pain, buttock pain or pain, tingling or numbness in the leg

Epidural steroid