Piriformis Muscle Injection


What is a Piriformis Muscle Injection?

  • The piriformis muscle is a pear shaped muscle that attaches at the sacrum and greater trochanter (hip socket).
  • A piriformis muscle injection involves the injection of local anaesthetic and either steroid or Botox into the piriformis muscle.
  • Botox is designed to stop the piriformis muscle from spasming for a period of up to 3 months. 
  • Steroid will reduce inflammation, irritation and swelling around the piriformis muscle.
  • This procedure is always performed in the day surgery using X-ray guidance. 


Prior to the Procedure

  • All blood thinning products (except aspirin) must be stopped prior to your procedure. You will be advised by letter when to stop taking these medications at the time that your admission date is arranged.
  • You are able to take your other regular medications with a sip of water on the morning of your procedure.
  • If you are an insulin dependent diabetic you will always be at the beginning of the list. Please bring your insulin with you and it will be given to you following your procedure.
  • Hamilton Day Surgery Centre staff will advise you of your fasting and admission times.
  • You must not have anything to eat, drink, smoke or chew prior to your procedure.
  • You will need to organise someone to drive you home after the procedure as you will not be able to drive for 24 hours after your procedure.


What Will Happen?

  1. You will be admitted to the day surgery by a nurse and you will be asked to change into a gown.
  2. The anaesthetist will speak with you and place a cannula (plastic needle) into a vein in your hand.
  3. In the procedure room, you will be assisted to position on the procedure table lying on your abdomen with a pillow under your hips and abdomen.
  4. The anaesthetist will give you some sedation into your vein. 
  5. An X-ray machine will be used to determine where the doctor will place the needle for your procedure.
  6. Local anaesthetic and either Botox or steroid will be injected once correct needle placement has been established with use of X-ray contrast (Omnipaque).
  7. The procedure will take approximately 10 minutes to complete.
  8. After the procedure, you will be placed on a trolley and taken to recovery, where you will remain for approximately 1 hour.
  9. After having something to eat and drink, you will be discharged with a carer.


Post Procedure

  • Gentle activity and rest is recommended in the first 24 hours following the procedure. You may then return to normal activity.
  • The local anaesthetic will wear off 12-18 hours following your procedure.
  • Botox will take approximately 5 days to start working. 
    • During the first 5 days you may experience some pain at the site of the injection and some flu-like symptoms. 
    • Other possible side effects include headache, temporarily increased pain, irritation of nerves at the site of the injection and rarely paralysis of muscle outside the area of spasm.
  • Steroid will take approximately 48 hours to start working.
    • During this time there may be a window of increased discomfort or pain.
  • Caution should be taken if any leg heaviness occurs. If this occurs, activity should be kept to a minimum until full leg sensation returns. 
  • A nurse from HPC will telephone you 24 to 48 hours following your procedure to check on your progress and organise a follow up appointment.

If you require further explanation of the procedure, please contact Hunter Pain Clinic nursing staff on (02) 4985 1800.


* Image by Patrick J. Lynch & KDS4444 [CC BY-SA 2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons