Sacroiliac Joint Injection and Radiofrequency Ablation

Nature of the procedure

The sacroiliac (SI) joints lie next to the spine and connect the sacrum (the triangular bone at the bottom of the spine) with the hip on both sides. Joint inflammation and /or dysfunction in this area can be a source of low back pain.

A sacroiliac (SI) joint injection is used to diagnosis and /or treat back pain. Based on the doctor’s assessment, the suspected SI joint is targeted. The procedure involves injecting a solution into/ around the SI joint(s) under the guidance of fluoroscopy (X-ray) or ultrasound imaging. The injected solution usually comprises a combination of local anaesthetic (LA) and steroids.

The procedure is performed while you are lying in the prone position. It is done under LA, and there is usually no need for sedation, unless radiofrequency ablation is being performed.

The injection serves two purposes:

1. Diagnostic - to determine the source of the pain

2. Therapeutic - to provide pain relief

As the injection is partly diagnostic, there is a possibility that you may not experience any pain relief from the procedure.

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

The purpose of the SI joint injection is to provide short term pain relief so that you may undergo physiotherapy with less discomfort. Physiotherapy should be continued to help build your core muscle strength that will in turn, provide a longer period of pain control.

Radiofrequency ablation is a procedure that uses heat to destroy the sensory nerves that supply the area causing your pain. It can potentially provide a longer duration of pain relief (compared to a steroid injection) but is also more costly.

Potential risks/complications of the procedure

As with all invasive medical procedures, SI joint injections have potential risks and complications associated with the needle placement or injectate. Overall, the risks are low and complications are rare.

a. Allergic reaction: Usually, the allergy is to the X-ray contrast or steroid; rarely to the local anaesthetic. Life threatening or severe allergies are rare.

b. Bleeding:

This is a rare complication. It is more common if you have underlying bleeding disorders or are on blood thinners.

c. Infection:

Minor infections may occur, but severe infections are rare.

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

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

e. Leg weakness: This is usually due to the spread of local anaesthetic to the nerves that supply the leg. The leg strength will recover once the local anaesthetic wears off.

f. Local anaesthetic toxicity: This is extremely rare.

g. Injury to pelvic organs:

This may occur if the needle is advanced beyond the SI joint into the pelvic cavity. This is rare.

h. Nerve damage:

While extremely rare, damage to the spinal/ peripheral nerves can occur from direct trauma from the needle and may result in leg weakness or paralysis.

Additional risks/complications related to radiofrequency ablation

If radiofrequency ablation is performed, additional side effects / risks/ complications include:

a. Aggravated pain / soreness over the next 1-2 weeks. This is common and is due to damage of the surrounding tissues from the RFA (burning).

b. Bruising at the injection site This may occur due to the use of larger needles and needle adjustment.

c. Permanent numbness: This may be an inadvertent side effect of ablating sensory nerves.

d. Permanent weakness: This is rare and may occur due to ablation of a motor nerve. This is avoided through the use of motor testing prior to ablation.

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, muscles weakness

i. Gastrointestinal effects

e.g. gastritis, ulcer, GI bleeding

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

k. Cortisone flare

You can discuss further questions regarding facet joint injection and radiofrequency ablation 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