Epidural Steroid / Nerve Root Injection

An epidural steroid injection (ESI) involves the administration of corticosteroids, together with a local anaesthetic, into the epidural space. ESI may be useful in patients with low back pain with concurrent radicular leg pain.

Nature of the procedure

The epidural space lies between the covering of the spinal cord (dura mater) and the vertebral spinal canal. This space contains spinal nerve roots, blood vessels and connective tissue.

The pain experienced can be from inflammatory processes at the nerve roots. The steroid reduces the inflammation and swelling of spinal nerve roots and other surrounding tissues. This may in turn reduce pain, tingling, numbness and other symptoms.

The procedure may fail to provide pain relief if there is no significant inflammatory component.

Indications for ESI include intervertebral disc prolapse, spinal stenosis, post herpetic/traumatic neuralgia, vertebral compression fractures and post laminectomy syndrome.

The aim of the ESI is to provide short term pain relief so that you can participate more actively in physiotherapy, which is important for long term pain control.

The duration and degree of pain relief from the ESI is variable (from weeks to months). You will be followed up to determine your response to the treatment, which will then guide your subsequent pain management plan, which may include repeated injections.

The ESI will be performed at the level of the suspected spinal pathology causing the pain (cervical, thoracic, lumbar or sacral). There are 3 common approaches:

1. Interlaminar (from the back)

2. Transforminal (from the side)

3. Caudal (from the bottom)

The ESI can be performed based on landmarks, or guided by imaging (either fluoroscopy or ultrasound). It is usually performed under local anaesthesia with no sedation required.

While an ESI targets mutliple spinal levels, a nerve root injection is a localised injection at a specific spinal nerve root. It can be used to relieve pain caused by that nerve root and/or to confirm if a suspected spinal level is causing your pain.

Potential risks/complications of the procedure

As with all invasive procedures, ESI and nerve root injections have potential risks and complications associated with the needle placement or injectate. Overall, the risks are low and complications are rare.

Allergic reaction: The allergy is usually due to the X-ray contrast or steroid. Rarely is it due to the local anesthetic. Life threatening or severe allergies are rare.

Bleeding: This may occur superficially (bruising) or deep (epidural haematoma).

Infection: Minor infections may occur, but severe infections (e.g., epidural abscess, meningitis) are rare. The risk is increased if you are immunecompromised or have an active infection.

Dural puncture (wet tap):

This may cause a post-dural puncture headache that usually improves within a week.

Nerve injury/spinal cord damage/paralysis:

While very rare, damage to the spinal cord or spinal nerves can occur from direct trauma from the needle, or secondarily from infection/ bleeding causing compression.

Discomfort at the point of injection or worsening of pain symptoms:

These symptoms are usually mild and short-lived. Long lasting increases in pain are rare.

Leg weakness: This may occur if the procedure is performed at the lumbar or sacral level. It is usually due to effect of the local anaesthetic on the nerves that supply the leg. If so, the leg strength will recover once the local anaesthetic wears off.

Potential side effects of steroid use

a. Facial flushing, headache

b. Elevated blood sugar

c. Elevated blood pressure, fluid retention

d. Skin thinning/bruising, weight gain

e. Suppression of hypothalamic pituitary axis (impaired stress response)

f. Impaired immunity (increased infection)

g. Neuropsychiatric effects (e.g., mood changes, irritability, confusion, insomnia)

h. Bone/muscle effects (e.g., osteoporosis, avascular necrosis, muscle weakness)

i. Gastrointestinal effects (e.g., gastritis, ulcer, gastrointestinal bleeding)

j. Eye effects: cataract, increased eye pressure (worsening of glaucoma)

k. Cortisone flare

You can discuss further questions regarding epidural steroid/nerve root injection with your chronic pain doctors when you visit the clinic.

Yishun Health is a network of medical institutions and health facilities of the National Healthcare Group in the north of Singapore. It comprises Khoo Teck Puat Hospital, Yishun Community Hospital and community extensions such as Admiralty Medical Centre and Wellness Kampung.

Khoo Teck Puat Hospital • (65) 6555 8000 • www.ktph.com.sg

Yishun Community Hospital • (65) 6807 8800 • www.yishuncommunityhospital.com.sg