What is a Piriformis Injection?


A Piriformis Injection is an injection of a long lasting steroid into the piriformis muscle in the pelvis. The injection is guided by a CT scanner and will help reduce inflammation or swelling around the nerves that pass near or through the piriformis muscle, often diagnosed as Piriformis Syndrome. This treatment may reduce leg and buttock pain, numbness, tingling or other symptoms that may contribute to nerve inflammation, irritation or swelling.

Piriformis Injection

What happens during a Piriformis Injection?

A. Before your scan

What to bring

  • Your request form
  • Any relevant previous imaging
  • Your Medicare card and any concession cards

Preparation – In the week before your scan

You must advise us of any blood-thinning medication your are taking such as Aspirin, Warfarin, Plavix or Iscover and stop taking it for a period of time before your treatment. Please contact us for advice.

Preparation – the day of your scan

There is no specific preparation and you may eat and drink as desired before and after the procedure. You will be asked to fill out a questionnaire regarding your health status, medication, and any known allergies. If there is any chance you may be pregnant, please inform us before your scan. You may also be asked to change into a gown and remove some jewellery for your scan.

B. During your Piriformis Injection


When you are transferred to the CT room you will be made comfortable on the examination table. The examination table slides you into the centre of the CT machine and some preliminary pictures are taken to confirm the scan position and the area of needle entry marked on your skin.

Your skin will then be cleaned and a local anaesthetic will be injected into site. This may temporary sting until the skin becomes numb (up to 30 seconds).

The radiologist will then insert a fine needle through the skin and tissues guided by images on the CT scanner, until it is in the correct area. Gas or contrast (x-ray dye) is then injected to confirm the correct depth of the needle. Once confirmed, a mixture of cortisone and local anaesthetic is injected. You may feel a sensation of pressure or a burning sensation.

Your procedure will take about 30 minutes.

Risks and side effects

A CT-guided Piriformis Injection is a very low risk procedure. Find out about CT Risks and Side Effects.

Other risks associated with this procedure include:

  • Pain or discomfort at the needle insertion site, or bruising after the procedure.
  • Temporary numbness or a tingling sensation can sometimes occur.
  • Inflammation which may involve redness or swelling and increased pain after 48 hours. Increasing pain or redness needs to be promptly reported to your referring doctor.

Any medical procedure can potentially be associated with unpredictable risks.

Who will perform my Piriformis Injection?

Our specialist medical imaging team will perform your Piriformis Injection.

Pars Defect Injection

What happens after a Pars Defect Injection?

How do I get my results?

After your appointment, the information from your scan is processed and interpreted by Envision’s medical imaging team before delivery of a report to your doctor.

Post-procedural Information

At the end of the procedure the needle will be withdrawn carefully from the insertion point and a band aid applied. You should be able to go about your daily activities after your appointment.

You should arrange for someone to collect you from your appointment.

Piriformis Injection

Download an Information and Consent Form