Interventional pain care

What is interventional pain care?

When back, neck or leg pain does not ease with exercise, physiotherapy and medicines, medicine can sometimes be placed right next to where the pain comes from. The doctor guides the needle with X-ray or ultrasound and sees its position on the screen.

These procedures do two things. They can ease pain for a while, and they can help find the source: if numbing one nerve reduces the pain, that pathway is probably involved.

What kinds of injection are there?

• Nerve root injection: local anaesthetic and steroid next to a nerve root, where it leaves the spine. Mostly for pain running from the back into the leg.
• Epidural injection: medicine is placed in the space around the covering of the spinal cord.
• Nerve block and facet joint injection: for pain from the small joints at the back of the vertebrae.
• Radiofrequency: heat is used to switch off part of a small nerve that carries pain. It is usually offered when test nerve blocks have worked.

Which one suits you, or whether you need an injection at all, is decided after an examination.

How is it done?

A spinal injection is usually a day procedure and needs no general anaesthetic. You lie on your front, the skin is cleaned and numbed, and the doctor moves the needle under imaging. A little contrast dye may be used to confirm its position. Pressure is normal, and you may briefly feel something like your usual leg pain.

A nerve root injection takes at least 15 minutes, and radiofrequency usually takes 30 to 60 minutes. Your total time at the centre is longer.

What should you expect?

• Your leg may feel numb or weak for two or three hours, so take care getting up.
• Pain and stiffness can increase for a few days.
• The steroid usually starts working in 5 to 10 days, sometimes up to 2 weeks. Its effect can last from several days to several months.
• The effect of radiofrequency usually appears after one or two weeks and lasts 3 to 18 months, because the nerve can grow back.
• For some people an injection does not work at all.

An injection does not remove the cause of the pain. The best use of a period with less pain is to strengthen your muscles and return gradually to movement.

Side effects

Common effects are temporary: bruising and tenderness at the needle site, headache, more pain for a few days and facial flushing. Steroid can raise blood sugar for a while and upset periods, so people with diabetes should check their sugar more often. There are also rare but serious risks, such as infection, bleeding near the nerve, allergic reaction and nerve injury that may be permanent. One hospital leaflet puts the risk of nerve damage from a nerve root injection at less than 1 in 10,000.

What should you tell us beforehand?

Tell us if you take a blood thinner, are or might be pregnant, are allergic to iodine or any medicine, have diabetes or have an infection. Do not stop any medicine yourself. Details are in the guide to before an injection.