Piriformis Injection: What Your Doctor Won’t Tell You

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piriformis muscle

It’s hard for both physicians and patients alike to understand the intense complexity of the connected body. It’s easier to come up with a description for one part that hurts and call it good. I call this “parting it out,” and this is definitely the case with a piriformis injection. Even though there are likely other reasons the piriformis is a problem, our “easy fix” medical care system loves an easy-to-understand label.

The Traditional Piriformis Story

piriformis injectionThe piriformis is a muscle that goes from the front of the tailbone to the outside of the hip. See the image to the right. The sciatic nerve in some patients can go through the muscle; in most others, it exits in front of and below the muscle. The sciatic nerve is one of the major nerve bundles that’s made up of a collection of spinal nerves from the low back and supplies the muscles in the leg. When the sciatic nerve is irritated by the piriformis muscle, the foot or leg can go numb or the muscles it supplies can develop pain and problems. Other times patients just develop a “pain in the butt” where the piriformis nerve travels.

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The Traditional Therapy Based on the Traditional Theory

piriformis injectionIf the piriformis muscle is tight and that’s causing pain in the muscle/tendon or irritating the nerve, then you need to stretch the muscle. Many different piriformis stretches have been described. To the right is the most common. You lie on your back and hook the foot on the side with the tight piriformis around the opposite knee and then pull that leg back, creating a stretch in the butt area.

A common piriformis injection therapy is steroid anti-inflammatories into the piriformis area, either blind or under ultrasound or fluoroscopic guidance. Finally, if none of that works, shockwave therapy may be tried. The idea here is to cause irritation in the muscle to try and kick off a healing response. Botox is another common piriformis injection concept. The idea here is that the Botox will temporarily relax the muscle. Finally, yet another piriformis injection strategy is platelet rich plasma (PRP). The idea here is that the growth factors in the PRP will help heal the damaged muscle and tendon.

If all else fails, some surgeons cut the muscle to try to free the nerve. This is a highly invasive treatment that obviously can have serious side effects. In addition, it destroys the normal biomechanics of the sacrum and SI joint.

However, none of these therapies answer a critical question. Why is the muscle tight in the first place? Let’s explore that idea.

What Does the Piriformis Muscle Do, and What Could Cause It to Be Tight?

Let’s first look at what we know from MRI research about the piriformis muscle. In one large MRI study, 86% of the patients had either an enlarged muscle or tendinopathy in the muscle tendon (tendon damage). Only about one in four patients had evidence that the sciatic nerve was involved. So what could make the muscle enlarged or beat up?

piriformis injectionWe’ve known since the ’90s that the piriformis muscle along with many ligaments are involved in stabilizing the sacroiliac (SI) joint. The SI joint lives between the tailbone and the back of the pelvis, so it makes sense that any muscle attached to the tailbone could have a role in stabilizing the joint. The joint is also stabilized by thick and extensive ligaments (see image to the left).

What would happen to the piriformis muscle if the SI joint ligaments were loose? It would go into overdrive to try and stabilize the sacrum (tailbone). This would explain why the piriformis is chronically tight, which in turn causes the muscle to get bigger and beat up.

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What Nobody Has Ever Told You About Piriformis Syndrome

So if the cause of the big and torn-up piriformis muscle is an unstable SI joint, why would we treat the muscle? That’s like trying to fix a torn-up tire that got that way because the lug nuts on the rim were loose by focusing on the tire. That approach makes no common sense. In fact, it makes more sense to tighten the lug nuts first and then repair the tire.

So how do you tighten the lug nuts here? You can inject a number of substances to tighten the SI joint ligaments. This can be something as simple as prolotherapy or orthobiologics, like platelet rich plasma or bone marrow stem cells. These are precise fluoro- or ultrasound-guided injections directly into specific ligaments.

The upshot? Always ask yourself why is this happening? Regrettably, most of medicine is focused only on the symptoms and thus only understanding a small part of the whole disease. This happens every day with piriformis syndrome. So why is the piriformis tight? It’s usually instability in the sacrum where the muscle is attached. Hence, if you fix the instability and the muscle, you get a more permanent fix that doesn’t destroy the normal biomechanics.

This blog post provides general information to help the reader better understand regenerative medicine, musculoskeletal health, and related subjects. All content provided in this blog, website, or any linked materials, including text, graphics, images, patient profiles, outcomes, and information, are not intended and should not be considered or used as a substitute for medical advice, diagnosis, or treatment. Please always consult with a professional and certified healthcare provider to discuss if a treatment is right for you.

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30 thoughts on “Piriformis Injection: What Your Doctor Won’t Tell You

  1. Linda Hicks

    WOW, finally a doctor that knows the biomechanics of the body and how to solve the problem!!! Are all of the doctors at Regenexx this knowledgeable?
    Thank you for this information.

    1. Regenexx Team


      We haven’t figured out how to clone Dr. Centeno yet! The selection process and training process of Regenexx Physicians is very intense and they reflect that. This explains: https://regenexx.com/blog/trust-regenexx-network-physicians/

  2. Julie

    Is it likely that overuse of gluteal muscles as required for classical ballet could inflame the piriformis muscle (bigger and beat up)? I was diagnosed with piriformis syndrome with an EMG. As someone with 48 years of classical ballet training and teaching, I find that when I am stressed I engage the gluteal muscles, and then I experience the spasms of the piriformis syndrome.

    You are right. I have been treated for the symptoms, not the cause.

    1. Regenexx Team

      Yes it can. Another common issue with ballet is a Ligamentum Teres issue. Please see: https://regenexx.com/blog/loose-hip-joint/

  3. Bryan Oneill

    How do you diagnose the instability at the SI joint ? None of the tests seem to be valid when scrutinized .

    1. Chris Centeno Post author

      History and exam. You know, like the good old days when doctors used to perform an exam for a full half hour?

  4. Patti

    Are there any stretches that will help alleviate this condition?
    And … is there anything you should NOT do that would make the condition worse?

    1. Regenexx Team


      We’ve included the “Piriformis Stretch” in the blog. The thing to be avoided to not make the situation worse would be Surgery!

  5. Angilina jensen

    My doc insists I do cortisol shots in hip to relieve pain but says I will need hip transplant once I’m bone on bone. Grrr doesn’t the cortisol shot do bad things to the bones so I won’t be able to have a hip transplant? I’m was a advice sports person now I’m a couch potato.. so sad.

    1. Chris Centeno Post author

      Yes, steroid injection in the hip reduce the likelihood of a successful hip replacement and kill cartilage, hence, based on the research at this point, not a good idea…

  6. Tommy Solberg

    is there a test to determine if the sacrum is unstable? Do you inject each of the SI Joint ligaments. If not, how will the offending ligament be recognized?

    1. Chris Centeno Post author

      Yes, there are physical exam tests to look for SI stability. Ultrasound is used to visualize and inject the SI ligaments.

  7. Kathleen

    Is there a way to find a doctor that does the ultrasound guided piriformis shot near me. One that actually takes my insurance. I have been looking and can’t find a doctor who does this let alone takes my insurance. I live in northern Indiana. Any help would be appreciated.

    1. Regenexx Team


      We don’t know of anyone doing this level of injection work that works with Insurance, but we’d be glad to help you locate the closest Regenexx Doctor that can help. Would you like our team to contact you?

  8. Robert Kowalik

    can you do a left pirfomis injection under a florescope? i have a script from my neurosurgeon.

    1. Regenexx Team

      Sorry, we don’t execute prescriptions from other Doctors. We’d be glad to examine you, see what’s causing the issue with your Piriformis muscle, and treat that.

  9. Karna Colby

    I am looking for a recommendation for the closest Regenexx Doctor that can help me to examine and determine the cause and best treatment for a chronically tight, painful piriformis.

    1. Regenexx Team

      We’d recommend Dr. Leiber or Dr. Amoroso at New Regenenortho in Sarasota, FL. Exams can be done in Tampa. Please see: https://newregenortho.com/

  10. Linda

    Do you know of any Regenexx Drs who treat si ligament instability in NJ. I did a lookup any found a Dr. Kranberg but when I called his office I was told he doesn’t do SI ligaments. Please help.

    1. Regenexx Team

      We will get back to you on Monday with that information.

  11. Moh

    Hi I have been suffering with piriformus for the last 2 years always have left cheek butt pain whilst driving and lying in bed any ideas or any dr recommended I am based in manchester England

  12. Dennis

    My wife is suffering from piriformis syndrome. She has had her left sacroiliac joint fused 2 years ago. She recently had a PRP injection in her left hip which has two tendon tears. Checking to see how long it may take to notice any difference in the piriformis

    1. Regenexx Team

      Hi Dennis,
      Every case is different, but this will give you and idea of how ligaments and tendons heal with regenerative injections: https://regenexx.com/blog/understanding-ligaments-repair-regen-med-treatments/

  13. Karen Daniels

    My husband is experiencing severe piriformis pain. He has had several lumbar , cervical surgeries 2′ severe stenosis/ congenital narrowing etc. His main pain is the piriformis now. It’s 6a and another sleepless night for us. I’m a nurse so I have a little increased ed but at my wits end watching this agony. He hasn’t had any probs since 2008, until now. I’m thinking because of compensation maybe he’s having this flare up? PT and meds are not doing anything, mri shows NOT neuro, this time! Please help. Any suggestions?

    1. Regenexx Team

      Hi Karen,
      Sorry to hear about your husband’s pain! The first step is figuring out what’s going on in this specific case. Unfortunately all surgery is damage to accomplisha goal: https://regenexx.com/blog/surgery-controlled-damage-accomplish-goal/ It would take reading the MRI images directly, not the report and an extensive exam. If you’d like to do that, please submit the “Are You a Regenexx Candidate” form here: https://regenexx.com/conditions-treated/spine/

  14. David Voisard

    I had the regenexx procedure for my si joint. It helped some. And the doctor is correct the piriformis muscle attaches at the hip and runs through the sacrum. Unfortunately to allow the si Joint ligaments to heal the piriformis needs to relax. When ever I stretch my piriformis my si Joint/ pelvis rotates out of place. I am now considering a steroid shot to the piriformis

    1. Regenexx Team

      Hi David,
      The piriformis won’t relax either due to the SI joint instability or irritated nerves in the low back. Multiple procedures may be needed to treat SI instability. A steroid shot won’t relax the muscle.

  15. Tammy

    Can you refer me to Regenexx doctor in Dallas, Texas

    1. Chris Centeno, MD Post author

      See the “Find a Clinic” tab above.

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