Pain in the buttock that radiates down the leg is commonly called sciatica. The most common cause for sciatica is irritation of the spinal nerves in or near the lumbar
spine. Sometimes the nerve irritation is not in the spine but further down the leg. One
possible cause of sciatica is piriformis syndrome. Piriformis syndrome can be
painful, but it is seldom dangerous and rarely leads to the need for surgery. Most people
with this condition can reduce the pain and manage the problem with simple methods, such as physical therapy.
This guide will help you understand
What parts of the body are involved?
The lower lumbar spinal nerves leave the spine and join to form the sciatic nerve. The sciatic nerve leaves the pelvis through an opening called the sciatic notch.
The piriformis muscle begins inside the pelvis. It connects to the sacrum,
the triangular shaped bone that sits between the pelvic bones at the
base of the spine. The connection of the sacrum to the pelvis bones
forms the sacroiliac joint. There is one sacroiliac joint on
the left and one on the right of the low back. The other end of the
piriformis muscle connects by a tendon to the greater trochanter, the bump of bone on the top side of your hip.
The piriformis muscle is one of the external rotators of the hip and leg. This means that as the muscle works, it helps to turn the foot and leg outward. Problems in the
piriformis muscle can cause problems with the sciatic nerve. This is because the sciatic
nerve runs under (and sometimes through) the piriformis muscle on its way out of the
pelvis. The piriformis muscle can squeeze and irritate the sciatic nerve in this area,
leading to the symptoms of sciatica.
Related Document: A Patient's Guide to Lumbar Spine Anatomy
What causes this problem?
The symptoms of sciatica come from irritation of the sciatic nerve. It's still a mystery
why the piriformis muscle sometimes starts to irritate the sciatic nerve. Many doctors
think that the condition begins when the piriformis muscle goes into spasm and tightens
against the sciatic nerve, squeezing the nerve against the bone of the pelvis.
In some cases, the muscle may be injured due to a fall onto the buttock. Bleeding in and around the piriformis muscle forms a hematoma.
A hematoma describes the blood that has pooled in that area. The
piriformis muscle begins to swell and put pressure on the sciatic
nerve. Soon the hematoma dissolves, but the muscle goes into spasm.
The sciatic nerve stays irritated and continues to be a problem. Eventually the muscle
heals, but some of the muscle fibers inside the piriformis muscle are replaced by scar
tissue. Scar tissue is not nearly as flexible and elastic as normal muscle tissue. The
piriformis muscle can tighten up and put constant pressure against the sciatic nerve.
What does the condition feel like?
Piriformis syndrome commonly causes pain that radiates down the back
of the leg. The pain may be felt only on one side, though it is
sometimes felt on both sides. The pain can radiate down the leg all the
way to the foot and may be confused for a herniated disc in the lumbar
spine. Changes in sensation and weakness in the leg or foot are rare.
people say they feel a sensation of vague tingling down the leg.
Sitting may be difficult. Usually people with piriformis syndrome do not like to sit.
When they do sit down, they tend to sit with the sore side buttock tilted up rather than
sitting flat in the chair.
How do doctors diagnose the problem?
Diagnosis begins with a complete history and physical exam. Your doctor will ask
questions about your symptoms and how the pain is affecting your daily activities. Your
doctor will also want to know what positions or activities make your symptoms worse or
better. You will be asked about any injuries in the past and about any other medical
problems you might have such as any arthritis that runs in the family.
Next the doctor examines you by checking your posture, how you walk,
and where your pain is located. Your doctor checks to see which back
movements cause pain or other symptoms.
Your skin sensation, muscle strength, and reflexes are also tested because it is
difficult to distinguish pain coming from the sacroiliac joint from pain coming from
other spine conditions.
If there is any question whether you might have an infection or some type of arthritis
affecting multiple joints, laboratory tests may be ordered. You may need to have blood
drawn and give a urine sample to send to the laboratory for special tests.
X-rays are commonly ordered of both the low back and pelvis. X-rays
can give your doctor an idea about how much wear and tear has developed
in the sacroiliac joint. X- rays of the lumbar spine and hips are also
helpful to rule out problems in these areas that may look and act like
sacroiliac joint problems.
Other radiological tests may also be useful. A magnetic resonance imaging
(MRI) scan can be used to look at the lumbar spine and pelvis in much
more detail and rule out other conditions in the area conditions. The
MRI scan uses magnetic waves rather than X-rays and shows a very
detailed picture of the soft tissues of the body.
A special type of MRI scan called neurography is being used more frequently to look at nerves. This uses a regular MRI scanner, but the computer settings are set to
look for areas of irritation along a nerve. This may change the way doctors use the
MRI to diagnose nerve problems such as piriformis syndrome, thoracic outlet syndrome, and carpal tunnel syndrome.
A bone scan is useful to see how the skeleton is reacting to
any type of "stress," such as an injury, an infection, or inflammation
from arthritis. Chemical "tracers" are injected into your blood stream.
The tracers then show up on special spine X- rays. The tracers collect
in areas where the bone tissue is reacting strongly to some type of
stress to the skeleton, such as arthritis and infection of the
The most accurate way to tell if the piriformis muscle is the cause of pain is with a
diagnostic injection into the muscle. The muscle is deep inside the buttock, so the
injection requires X-ray guidance with a fluoroscope, a CT scanner, or an open
MRI machine. Once the needle is placed in the muscle, an anesthetic can be injected
into the muscle to paralyze the piriformis muscle. If the pain goes away after the
injection, your doctor can be reasonably sure that the pain you are feel is from
What treatment options are available?
Doctors often begin by prescribing nonsurgical treatment for
piriformis syndrome. In some cases, doctors simply monitor their
patients' condition to see if symptoms improve. Anti-inflammatory
medications, such as ibuprofen and naproxen, are commonly used to treat
the pain and inflammation caused by the irritation on the nerve.
Acetaminophen (for example Tylenol®) can be used to treat the pain but
will not control the inflammation.
You'll probably work with a physical therapist. After evaluating your condition, the
therapist uses treatments to ease spasm and pain in the piriformis muscle. Exercises,
particularly stretching exercises, are given to try and relieve irritation on the sciatic
If you still have pain after trying these treatments, your doctor may suggest injections.
The main use of injections is to see if your pain is from piriformis syndrome. An
injection of local anesthetic such as lidocaine can be injected into the muscle to
temporarily relax it. This loosens up the muscle and reduces the irritation on the
sciatic nerve. Other medications have also been injected into the piriformis muscle.
Cortisone, for example, may be mixed with the anesthetic
medication to reduce the inflammation on the sciatic nerve. Cortisone
is a potent anti-inflammatory medication
that is commonly used both in pill form and in injections to treat
Botulism injection therapy (also known as Botox® injections)
can be used to actually paralyze the piriformis muscle. This makes the
muscle relax, which helps take pressure off the sciatic nerve. The
effect of the Botox® injection isn't permanent; it generally only lasts
a few months. In the meantime, however, it is hoped that a stretching
program can be used to fix the problem. In other words, when the
injection wears off, the muscle may have been stretched enough so that
the symptoms do not return.
Surgery may be considered but usually only as a last resort. There
are two procedures in use. The first is to cut the piriformis tendon
where it attaches on the greater
trochanter (the bump on the side of your hip). The other method is to
cut through the
piriformis muscle to take pressure off the sciatic nerve.
These procedures are usually done on an outpatient basis, meaning
that you will be able to go home the same day as the surgery. In some
cases, you may need to stay in the
hospital for one night. Both procedures can be done under general
anesthesia or under a
spinal type of anesthetic.
The surgeon begins by making a small incision, usually about three inches long, in the buttock. The fibers of the gluteus maximus, the largest buttock muscle, are split. This
gives the surgeon a way to see deep into the buttock and locate the piriformis muscle.
When the piriformis muscle and tendon can be seen, the surgeon then cuts (releases)
the tendon where it connects to the greater trochanter.
If more room is needed to release the pressure on the nerve, a
portion of the piriformis muscle may be removed. This usually doesn't
cause problems with strength because there are several much stronger
muscles that help turn the leg outward.
What should I expect as I recover?
Most patients with piriformis syndrome work with a physical therapist. Plan to attend
physical therapy sessions two to three times each week for six to eight weeks.
Your therapist begins by evaluating your condition. This includes attention to the low
back, as well as the sacroiliac and hip joints.
Physical therapy treatments for piriformis syndrome often begin with
heat applications. Heat is used to help the piriformis muscle relax,
easing spasm and pain. Your physical therapist may place a hot pack
over your buttocks muscle.
Ultrasound is another treatment choice that can be set for deep heating in the buttock
area. Ultrasound uses high frequency sound waves that are directed through the skin. The
deep heating effect of ultrasound is ideal for preparing the piriformis muscle for hands-
on forms of treatment and for getting the muscle to stretch out.
Hands-on treatments such as deep massage and specialized forms of soft-tissue
mobilization may be used initially. Your therapist may also position your hip and leg in
a way that helps to relax nerve signals to the piriformis.
The keystone treatment for piriformis treatment is stretching. Stretching is especially
effective following heat and hands on treatments. Your therapist will position you in
ways that help you get a good stretch on the piriformis muscle. Along with the stretches
you'll do in the clinic, you'll be shown several ways to stretch the muscle on your own.
You need to do your stretches every few hours. Be gentle and cautious as you stretch to
avoid overdoing it.
As your symptoms ease, your therapist will gradually advance your
program to include posture training, muscle strengthening, and general
Your surgeon may prescribe physical therapy after surgery for
piriformis syndrome. You'll probably only need to attend sessions for
four to six weeks. Expect full recovery to take up to three months.
During therapy after surgery, your therapist may use treatments such as heat or ice,
electrical stimulation, massage, and ultrasound to help calm pain and muscle spasm. Then
you'll begin learning how to move safely with the least strain on the healing area.
As the rehabilitation program evolves, you'll begin doing more
challenging exercises. The goal is to safely advance strength and
As the therapy sessions come to an end, your therapist helps you get back to the
activities you enjoy. Ideally, you'll be able to resume normal activities. You may need
guidance on which activities are safe or how to change the way they go about their
When treatment is well under way, regular visits to your therapist's office will end.
Your therapist will continue to be a resource. But you'll be in charge of doing your
exercises as part of an ongoing home program.
Last Updated on Thursday, 27 July 2006 13:15
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