Piriformis injections

Your doctor has referred you to the Pain Clinic for specialist advice on your pain.

The Consultant in Pain Management has recommended that you consider an injection of local anaesthetic and steroid to the piriformis muscle.

Please make sure you have someone to collect you afterwards as you should not drive home after your treatment. This leaflet aims to explain this procedure to you and to answer some of the questions you may have. Please read it carefully. Ask if there is anything you do not understand.

Before your consent to treatment the Consultant will discuss the expected benefits and risks with you.

What is it?

The injection is given to relieve buttock pain that may be radiating into the back of the thigh and sometimes down the leg. Your pain may be caused by irritation of the sciatic nerve by the piriformis muscle which may be chronically contracted or tense. This is often called piriformis syndrome.

In some cases the procedure may have to be repeated as many as three times. However, you may feel a
benefit after one or two injections.

The piriformis muscle begins inside the pelvis. It connects to the sacrum, the triangular shaped bone that sits between the pelvic bones at the base of the spine. The connection of the sacrum to the pelvis bones forms the sacroiliac joint. There is one sacroiliac joint on the left and one on the right of the low back. The other end of the piriformis muscle connects by a tendon to the greater trochanter. This is the bump of bone on the top side of your hip.

You have piriformis muscle, one on each side though you may have pain on one side only.

How do piriformis steroid injections work?

They are used to:

• try and reduce inflammation around the sciatic nerve, and
• hopefully reduce the severity of any pain caused by the inflammation
• dampen down pain signals caused by damage to peripheral nerves

The mixture of local anaesthetic and steroid is injected into the piriformis muscle, which is close to the
sciatic nerve. Injecting steroids into the piriformis muscle is not a licensed use of the drug. However there is some evidence that these injections can be helpful.

The aim of this injection is to place a small amount of local anaesthetic and steroid (depomedrone) close to the piriformis muscle. This will be done using a fine needle. This will hopefully reduce inflammation and reduce pain.

Will it help?

Unfortunately there are no guarantees as to how much pain relief you will get or how long it will last for.

Everyone's pain is unique and responds differently. This injection may be helpful or make no change to your symptoms.

The procedure - what to expect?

This procedure is carried out at the Borders General Hospital. Below is a summary of what to expect.

• the Consultant will review any changes to your general health
• you are asked to bring with you an up to date list of any medicines you are taking
• you will be asked a number of questions, often more than once - this is designed for safe care
• after discussion with the Consultant you will be asked for your consent to the procedure
• you will be asked to take off your lower garments (not underwear) only and asked to make yourself
  comfortable on the bed
• you will need to lie on your non- painful side - you will be shown the best position to lie

The area to be injected is cleaned with antiseptic and the skin numbed with an injection of local anaesthetic. This can sting a little at first. The doctor will examine you to try to find the painful spot.

A small amount of local anaesthetic and steroid is then injected.

Local anaesthetics may sting for a few seconds. Piriformis injections are not normally painful. Extra local anaesthetic can be given if needed. As the injection is given you may feel a slight and temporary increase in your pain. This does not last long.

• temporary numbness of the leg which usually wears off after 2 to 4 hours.
• irregular menstrual periods due to hormonal imbalance. This is caused by the Depomedrone and usually does not last long.
• post menopausal bleeding (a "period" which happens after your normal periods have stopped) due to hormonal imbalance. This is caused by the Depomedrone and usually does not last long.
• depomedrone may cause a temporary rise in blood sugar levels in diabetics. Non-insulin dependent
  diabetics do not normally need to take any further action. Those taking insulin may need a slight increase in their insulin dose.

Please ask your family doctor for further advice about this.

What are the possible complications of this treatment?

• local soreness or bruising where the injection has been given - this usually settles within a few days
  no pain relief is probably the most common side effect, for reasons already given
• the pain may be worse afterwards rather than better - this is unusual and the cause is not understood
• temporary numbness in the leg(s) which usually wears off after a few hours. This only happens if local anaesthetic spills from the piriformis muscle to the sciatic nerve
• there are other possible side effects, including infection or nerve damage. These are extremely rare and you are advised to speak with your consultant before the procedure if you have any further questions

If you become aware of any different or unusual feelings then just report these to the staff who will be with you.

You will normally be able to get up off the trolley by yourself and walk normally.

Pain relief may happen in the following ways:

1. Immediate relief lasting for several weeks
2. Worse for a while and then relief for several weeks
3. No change at first and then gradual relief over several weeks

But sometimes no pain relief happens at all.

You may go home as soon as you feel ready.

Please make sure you have someone to collect you afterwards as you should not drive home.

It is important to feed back your response from the procedure. A Follow up plan will be arranged at the
appointment.

Useful contact details

If you still have any questions after reading this leaflet, please contact the Pain Clinic via the following:

Pain Clinic Nurse Specialist tel:01896 826335 Or leave a message with the Pain Clinic Secretary / answer phone   tel:01896 826323 and we will return your call.