Piriformis Muscle Injection With Fluoroscopy

Side-by-side of final flow

Side-by-side of final flow

By Chris Faubel, M.D. –

To learn about Piriformis Syndrome, follow this link.

A piriformis muscle injection should be performed with fluoroscopic (x-ray) or ultrasound needle guidance in order to confirm proper placement of the needle as the muscle lies deep to the buttock adipose tissue and gluteus maximus muscle and can not be done safely or effetively “blindly”.

ICD-9 code:

  • 355.9 – Piriformis syndrome (mononeuritis)

CPT codes: 

  • 20552Trigger point injections, 1-2 muscles”
  • 77002 “Fluoroscopic guidance, non-spinal”
  • Remember to bill for the injectables (contrast, steroid) if done in an office procedure room

Solution (injectable):

  • Corticosteroids:  40-mg of Depo-Medrol or Kenalog
  • Local anesthetics:  3-5-ml of local anesthetic (lidocaine or bupivacaine)
  • Note:  Can also be done with botulinum toxin (Botox, Myobloc, Dysport) for longer relief than steroid and local anesthetic.


  • Prone

Fluoroscopy starting position

  • An A-P view is adjusted so that the inferior most part of the sacroiliac joint is in the middle of the screen.

Technique (Piriformis Muscle Injection with Fluoroscopic Guidance):

  • Use an 18-gauge 1.5″ needle tip is placed on the cleaned skin over the inferior SI joint.
  • Create a skin wheal and anesthetize the deeper subcutaneous skin with 1% lidocaine (buffered with sodium bicarbonate) and a 27-gauge 1.25-inch needle.
  • A 22-gauge 3.5″ or 5″ (depending on patient size) Quincke needle is used to advance down and contact the very tip of the inferior sacroiliac joint. Make note of the approximate needle depth.
  • The needle is then withdrawn and redirected to a final TARGET SITE 1-cm inferior, 1-cm lateral, and 1-cm deeper than the SI joint.
  • Note:  I frequently notice a change in resistance (more firm) as the needle enters the piriformis muscle for some reason.
  • Important:  NEVER inject if the patient is feeling sharp pain shooting down their leg as the needle tip may be inside the sciatic nerve.  Move the needle and retry.

TARGET SITE:  1-cm inferior, 1-cm lateral, 1-cm deeper [from the inferior SI joint]

Contrast Flow:

  • AP view:  Contrast should flow in a diagonal pattern from cephalad to caudad as it goes toward the femoral attachment site of the piriformis muscle.
  • Lateral view:  See the side-by-side pic below

Starting A-P image such that the bottom of the SI joint is in the middle.

Advance down to the inferior end of the posterior SI joint opening to gauge depth.

Pull back and redirect to the final needle position (see text above)

Inject contrast to see the diagonal flow pattern of the piriformis muscle.

Final spread of contrast after injecting the steroid/local solution.

Piriformis muscle flow pattern on lateral imaging.


  1. I have been suffering with piriformus syndrome for the last year and the pain is excruciating. I have had several (over 8) injections of steroid, lidocaine and one of toradol. All of these injections have been done either under xtay in the hospital or under ultrasound in my Dr.’s office. Thay have not given much relief so i inquired about botox about 8 months ago. So i was referred to another Dr. In the same practice. I met with him 4 weeks ago and he thought i might get some relief with the botox. I was scheduled today and went in this morning. This Dr. Was going to have me lay on the table and give me a botox injection in my piriformus muscle. I asked how he was going to find it. He said by pushing to see where it hurt and then inject into the pirifomus till i told him where i feel the muscle jump. I told him i cannot tell by pushing on it. It doesnt hurt like that. Well he assures me that it takes skill to do these injections and he knows where the pirifomus muscle is. He left the room to mix my botox shot and i got even more nervous thinking to myself this is wrong. How is he going to be sure he’s injecting the right place and with botox of all things! When he came back i was almost in tears. I said im not so sure about doing this without ultrasound. I felt like an idiot and i was wasting his time. I apologized and said i would be more comfortable under ultrasound. He said he doesnt do ultrasound. So i decided to wait for the injection even though im in terrible pain. He said he would put my mixed needle in the fridge for next week so my other Dr. Can do it under ultrasound. My other Dr. Doesnt do botox injections so i dont know what will happen. This Dr. I saw today said that my original dr. Will give me a trigger point injection and i said ok but with the botox right? He said it doesnt matter whats in the needle. I said well ive been waiting for this botox for 8 months and of course it matters whats in the needle! Ive tried all the steroid and lidocaine etc and i want the botox to help ease my pain. He made me feel stupid. I know im not a dr but i believe that i made the right decision to not just let this man stick a needle full of botox in my butt without a 100% guarantee that it is in fact going in my piriformus muscle. I have no ides what he wrote in my file but he said that he agreed i shouldnt get the shot. Now i dont know if i insulted his intelligence by actions and words. So i have 2 questions for you #1 Do you think i made the right decision? And #2 will this mixed botox needle be ok in the fridge for a week till i can have the injection under ultrasound? Please respond to me. I am desperate and in pain and now im afraid that this Dr. Put some thing in my file that im paranoid or anxiety ridden. I was nervous today. I always am. I dont like needles. But i felt very torn today because i want that shot!

    • I don’t want to and won’t speak ill of another physician, but I will say that I personally wouldn’t allow someone to give me an injection with botox or steroid/lidocaine into the piriformis muscle without either fluoroscopy or ultrasound guidance. Without imaging guidance, it’s a complete educated guess. As for the mixed botox, I’m not really sure how long it will last in the fridge. Sorry.


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