Piriformis syndrome is a condition in which the piriformis muscle, located in the buttock region, spasms and causes buttock pain. The piriformis muscle can also irritate the nearby sciatic nerve and cause pain, numbness and tingling along the back of the leg and into the foot (similar to sciatic pain).
The Piriformis Muscle
The piriformis muscle is a small muscle located deep in the buttock (behind the gluteus maximus).
The piriformis muscle:
- Starts at the lower spine and connects to the upper surface of each femur (thighbone)
- Functions to assist in rotating the hip and turning the leg and foot outward
- Runs diagonally, with the sciatic nerve running vertically directly beneath it (although in some people the nerve can run through the muscle).
Causes of Piriformis Syndrome
The exact causes of piriformis syndrome are unknown. Suspected causes include:
- Muscle spasm in the piriformis muscle, either because of irritation in the piriformis muscle itself, or irritation of a nearby structure such as the sacroiliac joint or hip
- Tightening of the muscle, in response to injury or spasm
- Swelling of the piriformis muscle, due to injury or spasm
- Bleeding in the area of the piriformis muscle.
Any one or combination of the above problems can affect the piriformis muscle (causing buttock pain) and may affect the adjacent sciatic nerve (causing pain, tingling, or numbness in the back of the thigh, calf, or foot).
There is no simple diagnostic test for piriformis syndrome causing irritation of the sciatic nerve. The condition is primarily diagnosed on the basis of the patient’s symptoms and on a physical exam, and after excluding other possible causes of the patient’s pain.
Symptoms of Piriformis Syndrome
Most commonly, patients describe acute tenderness in the buttock and sciatica-like pain down the back of the thigh, calf and foot. Typical piriformis syndrome symptoms may include:
- A dull ache in the buttock
- Pain down the back of the thigh, calf and foot (sciatica)
- Pain when walking up stairs or inclines
- Increased pain after prolonged sitting
- Reduced range of motion of the hip joint
Symptoms of piriformis syndrome often become worse after prolonged sitting, walking or running, and may feel better after lying down on the back.
Diagnosing Piriformis Syndrome
Diagnosis of piriformis syndrome is based on a review of the patient’s medical history, a physical examination and possibly diagnostic tests.
Piriformis syndrome is often a diagnosis made through a process of ruling out other possible conditions that may be causing the patient’s symptoms, such as a lumbar disc herniation or sacroiliac joint dysfunction.
The physical exam will include an examination of the hip and legs to see if movement causes increased low back pain or lower extremity pain (sciatica pain).
Typically, motion of the hip will recreate the pain. The exam will also identify or rule out other possible causes of the sciatica pain, such as testing for local tenderness and muscle strength.
A medical history includes an in-depth review of the patient’s symptoms, such as what positions or activities make the symptoms better or worse, how long the symptoms have been present, if they started gradually or after an injury, and what treatments have been tried.
It will also include a review of conditions that may be in the patient’s family, such as arthritis.
X-rays and other spinal imaging studies cannot detect if the sciatic nerve is being irritated at the piriformis muscle. However, diagnostic tests (such as X-rays, MRI and nerve conduction tests) may be conducted to exclude other conditions that can cause similar symptoms to piriformis syndrome.
An injection of anesthetic with or without steroids may help to confirm if the piriformis muscle is the source of the symptoms.
Depending on the severity of the patient’s sciatica-type pain and other symptoms, a number of treatment options may be recommended by a health care professional.
A comprehensive approach to managing piriformis syndrome may include a combination of the following nonsurgical treatments:
Ice and Heat Therapy for Piriformis Syndrome
Ice Packs and Ice Massage
At the onset of pain, lie in a comfortable position on the stomach and place an ice pack on the painful area for approximately 20 minutes. Repeat as needed every 2 to 4 hours.
It may be more helpful to combine a gentle massage with the ice. Lie on the stomach and have someone gently massage the painful area with a large ice cube. If ice is applied directly to the skin (instead of a cold pack), limit it to 8 to 10 minutes to avoid an ice burn.
If specific activities are usually followed by increased pain, it may be a good idea to apply ice immediately following the activity.
Some people find it helpful to alternate cold with heat. If using a heating pad, lie on the stomach and place the heating pad on the painful area for up to 20 minutes. Be sure to avoid falling asleep on a heating pad, as this may lead to skin burns.
Medications for Sciatica Pain
Since most episodes of pain include some type of inflammation, non-steroidal anti-inflammatory medications (NSAIDs), such as ibuprofen or naproxen, may help decrease inflammation in the affected area.
For severe sciatica pain from piriformis syndrome, an injection may be part of the treatment.
A local anesthetic and corticosteroid may be injected directly into the piriformis muscle to help decrease the spasm and pain. The purpose of an injection is usually to decrease acute pain to enable progress in physical therapy.
For persistent piriformis spasm that is resistant to treatment with anesthetic/corticosteroid injections, an injection of botulinum toxin (e.g. Botox®), a muscle weakening agent, may be useful. The goal of the injection is to help the muscle relax and help reduce pressure on the sciatic nerve.
The goal with both injections is to help the patient progress with stretching and physical therapy, so that when the effect of the injection is over the muscle will be remain stretched and relaxed.
Electrotherapy for Piriformis Syndrome
The application of electrical stimulation to the buttock with a transcutaneous electrical nerve stimulation (TENS) unit can help to block pain and reduce muscle spasm related to piriformis syndrome.
To watch a video about piriformis syndrome, click below: