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Piriformis Injection

The piriformis muscle is one of the muscles deep in the buttocks that rotates the leg outwards. The sciatic nerve runs very close to this muscle.

If the muscles become tight, it can put pressure on the sciatic nerve, causing pain in the buttock and radiating down the leg. The piriformis injection deposits a small amount of local anesthetic (numbing medication) and steroid (anti-inflammatory) into the muscle to relieve the pain.

Patient guidelines (PDF) ›

Procedure overview (PDF) ›

What is the goal of a piriformis injection?

The goal of a piriformis injection is to provide pain relief so that you are able to resume normal activities. In many cases, we will prescribe a course of physical therapy to help you return to a normal level of activity.

What happens before a treatment?

You will be escorted to a room where a nurse will conduct a pre-procedure interview.

The physician who will perform the injection reviews your medical history, previous imaging studies, current medications and physical exam results in order to help plan the best approach for the injection. If you have not had a physical exam prior to the injection, the physician will perform an exam at this time.

What happens during the procedure?

You will remain awake during the entire process. Blood pressure, heart rate and breathing are continually monitored.

After you are lying face down on the procedure table, the injection site is cleansed with an antiseptic. This procedure involves inserting a needle through the skin, muscle and soft tissues, so there is some slight discomfort involved.

An injection of local anesthetic (numbing medication) will be administered in the area where you are experiencing pain. The physician then directs a needle with the use of X-ray guidance and deposits the medication. This procedure takes approximately 30 minutes.

Should I limit my activity or change my diet after the injection?

No. Unless your doctor tells you otherwise, you may return to your usual activities.

Are there any side effects caused by piriformis injection?

  • Immediately after the injection, you may feel that your pain is gone or is much less. This pain relief is often the result of the local anesthetic (numbing medication) and will usually only last a few hours. Your usual pain will follow. Pain relief from the steroid (anti-inflammatory) medication usually takes several days to appear.
  • You may experience mild pain at the site of injection for several days. You may also experience a temporary increase in your usual pain after the injection.
  • You can apply ice to the area for as long as 15 minutes, three to four times a day.
  • You may experience some dizziness during or soon after the injection.

For diabetic patients

If you have diabetes, it is important to know the steroid (anti-inflammatory) can cause an elevation in your blood sugar level for up to two weeks after the injection. You should check your blood sugar more often than usual for several days after an epidural steroid injection. If your blood sugar is elevated, please contact the doctor who manages your diabetes for instructions on how to change your diet and/or adjust your diabetes medication.

Are there any restrictions after piriformis injection?

Yes. You should follow these restrictions after the procedure:
  • Do not drive for the remainder of the day.
  • Do not take a tub bath or soak in water (pool, hot tub) for 24 hours after the injection.
  • Wait three days after the procedure before resuming physical therapy.

What are the medications used for piriformis injection?

  • Lidocaine or bupivacaine are local anesthetics that are used to numb the area of injection; this numbness usually wears off within two to six hours.
  • Triamcinolone (Kenalog®) is a steroid used to treat inflammation and pain. The effects of this steroid may take up to 10 days to appear.
  • Lopamidol, an X-ray contrast agent, may be injected into the area to confirm correct placement.

When should I call my doctor?

You should call your doctor immediately if any of the following occurs:
  • Swelling, redness, bleeding or discharge from the site of the injection
  • A fever greater than 100˚F
  • New or worsening back or neck pain
  • New numbness or weakness in your arms or legs
  • Difficulty with urination after the injection, such as suddenly losing control of your bladder
  • Difficulty with bowel movements after the injection, such as suddenly losing control of your bowels
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