The piriformis muscle is present in the buttocks, connecting the sacrum to the outer surface of the hip. This muscle enables us to walk and run. The sciatic nerve is a thick, long nerve passing through or below the piriformis muscle. A spasm in or inflammation of the piriformis muscle can compress the sciatic nerve resulting in severe pain in the low back or gluteal area and often radiating into the leg (eg "sciatica" or "piriformis syndrome").
The medication injected, typically a local anesthetic and steroid is meant to break up a reduce inflammation in the muscle and associated sciatic nerve. This may in turn reduce pain, and other symptoms caused by tight muscles and inflammation around the nerve causing pain. It is important to understand that a piriformis injection alone is not a treatment for piriformis syndrome, it allows you to participate in exercises and stretching which will ultimately be the cure for your pain.
You will need a ride home. We advise the patients to take it easy for a day or so after the procedure. You may want to apply ice to the affected area. Perform the activities as tolerated by you. Unless there are complications, you should be able to return to work the next day. The most common thing you may feel is sore joint.
The actual injection takes only a few minutes. The procedure involves inserting a needle through skin and deeper tissues. So, there is some pain involved. However, a very thin needle is used and the pain is usually minimal and well tolerated by the patient. Immediately after the injection, you may feel that your pain may be gone or quite less. This is due to the local anesthetic injected. If the patient adheres to stretching and exercise recommendations the lasting effects of the injection may be indefinite. Following the procedure you may experience nausea, sweating, and/or dizziness. You may also develop weakness or numbness in the leg for a few hours or up to one day. You may also notice a slight swelling, redness, bruising, and tenderness at the injection site, which may subside within a short period of time. Once the physician has confirmed that you are stable, you will be discharged to go home.
Generally speaking, this procedure is safe. However, with any procedure there are risks, side effects and possibility of complications. The most common side effect is pain - which is temporary. The other risks involve, infection, bleeding, worsening of symptoms etc. Further potential complications are associated with the steroid medication itself to include but not limited to elevated blood sugar for up to 4 days (if you are diabetic), kidney damage or failure (rare), Cushing's syndrome, or allergic reaction to the medication. Fortunately, the serious side effects and complications are uncommon.