• Highlights
• Introduction
• Causes
• Risk Factors
• Diagnosis
• Medications
• Complementary and Alternative Medicine
• Exercise and Physical Therapy
• Surgery
• Other Treatments
• Specific Treatment for Acute Low Back Pain
• Specific Treatment for Chronic Low Back Pain
• Prognosis
• Complications
• Prevention
• Resources
• References

Back pain and sciatica

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of back pain, including sciatica.

Alternative Names

Herniated disk; Sciatica

Diagnosis

Because nearly all cases of low back pain clear up in a short time and are not due to serious problems, a medical history and a brief physical examination are almost always sufficient.

Still, with very severe or chronic back pain, it is important that any serious medical causes as well as cauda equina syndrome and progressive nerve damage be ruled out first. If the doctor suspects a serious underlying cause, the approach to determining the origin of back pain involves answering three questions:

• Is some general medical disorder present that could be causing the pain?
• Are there social or emotional factors that might be intensifying the pain?
• Are the nerves in the spine involved in the pain (such as in sciatica)?

Such questions can usually be answered with a medical history and physical examination.

Medical History

A patient should report any serious health problems and concerns during a medical and family history, especially those listed below.

• Previous episodes of back pain
• Any injuries or accidents involving the neck, back, or hips
• History of cancer
• Unexplained weight loss or chronic infection
• The frequency, duration, and nature of the back pain
• When the back pain occurs
• What triggered the pain (such as lifting a heavy object)
• Conditions that make the pain worse such as coughing
• Any situation that relieves the pain
• Urination of bowel movement problems
• Other relevant symptoms such as morning stiffness, weakness, or numbness in the legs.

Physical Examination

The main goal of a physician exam is to try and determine the source of the pain and to determine limits of movement.

• Patients are asked to sit, stand, and walk in different ways (flat-footed, on the toes, and on their heels).
• In some cases they are asked to walk on a treadmill to test for weakness in toe or heel walking (which may indicate stenosis).
• Patients will be requested to bend forward, backward, and sideways and to twist.
• Patients will be asked to lift their leg straight up while lying down. The doctor will also move the patient's legs in different positions and bend and straighten the knees. (Pain caused by sciatica can be intensified by lifting the affected leg straight in the air. It is usually sharp, localized, and accompanied by numbness or tingling. Pain caused by inflammation is duller and more generalized and not affected by lifting a straight leg.)
• The doctor may measure the circumference of the calves and thighs to look for muscle deterioration.
• To test nerve function and reflexes, doctors will tap the knees and ankles with a rubber hammer. The doctor may also touch parts of the body lightly with a pin, cotton swab, or feather to test for numbness and nerve sensitivity.

Imaging Techniques

Because most patients with back pain are on the mend or completely recovered within 6 weeks, imaging techniques such as x-rays or scans are rarely recommended in the first month unless a tumor, fracture, infection, cauda equina syndrome, or progressive neurologic disease is suspected.

Patients who have the following symptoms or experienced certain events may need imaging studies.

• Pain that lasts more than a month
• Very severe or progressive pain, numbness
• Muscle weakness
• A previous accident or injury that might have affected the back
• A history of cancer
• Indications of an underlying disease such as fever or unexplained weight loss
• Pain that occurs in patients over 65 years of age

If these conditions exist, usually an x-ray is used first. If results are inconclusive, either computed tomography (CT) or magnetic resonance imaging (MRI) may be performed. (Ultrasound is not useful.)

X-Rays. Although many patients with acute and uncomplicated low back pain believe that plain x-rays of the spinal column are important in a diagnosis, they are not very helpful in most patients except for reducing anxiety. If pain persists after 6 to 8 weeks, then x-rays are usually warranted. In such cases, x-rays may reveal signs of injury, infection, tumors, stenosis, or changes in the vertebrae that may be causing inflammation or compression on the nerve. There are many different types of x-rays for the spine.

• A diskography is an x-ray of the disk. This procedure requires injections into disks suspected of being the source of pain and disks nearby. It can be painful and is generally only used for patients who are undergoing back surgery to identify the location of the injured disk.
• An x-ray myelogram is an x-ray of the spine that requires a spinal injection of a special dye and the need to lie still for several hours to avoid a very painful headache. It has value only for select patients with pain on moving and standing. It has largely been replaced by CT and MRI scans.

Magnetic Resonance Imaging (MRI) .Magnetic resonance imaging (MRI) can provide very well-defined images of soft tissue and bone. It is not painful, but some people may feel claustrophobic in scanners that are fully enclosed. MRIs can detect annular tears, or disk fragments, and non-spinal causes of back pain, including infection and cancer. However, MRIs are no more effective than x-rays in identifying arthritis, and they are more expensive. Some medical evidence suggests that relying on MRI images of disk abnormalities to determine treatment has resulted in many unnecessary surgeries. At least 40% of all adults have bulging or protruding vertebral disks, and most have no back pain. The degree of disk abnormalities revealed by MRIs often have very little to do with the severity of the pain or the need for surgery. Disk abnormalities in people who have back pain may simply be a coincidence rather than an indication for treatment.

Advanced imaging techniques should be used only when underlying infection, cancer, or nerve involvement is suspected.

Magnetic Resonance Neurography . This imaging exam looks at the nerves in the pelvic area. Researchers reporting in the Journal of Neurosurgery found that it helped reveal pinched nerves that can cause leg pain. The findings could lead to new ways to diagnose sciatica and piriformis syndrome.

Bone Scintigraphy and SPECT Imaging. In rare cases, doctors may use bone scintigraphy (bone scanning) to determine abnormalities in the bones. The technique may be useful for early detection of spinal fractures, cancer that has spread to the bone, or osteoarthritis. During this exam, a small amount of radioactive material is injected into a vein. It circulates through the body, and is absorbed by the bones. The bones can then be visualized using x-rays or single photon emission computed tomography (SPECT). A study in the February 2006 journal Radiology found that SPECT can help determine which patients would get low back pain relief from spinal injections. Forty-seven patients were randomly divided into two groups: One group received SPECT before they were scheduled for an injection, the other group did not. Those who showed spinal problems on the SPECT images received an injection in the area of the abnormalities. Those who had a normal SPECT, as well as those who did not have the test at all, received injections in the area recommended by their referring physician. After a month, those who had targeted injections using the SPECT images had greater pain relieve than those who did not.

Electrodiagnostic Tests

Electrodiagnostic tests that analyze the electric waveforms of nerves and muscles may be useful for detecting nerve abnormalities that may be causing back pain and identifying possible injuries. They are also useful to determine if any abnormal structural findings on an MRI or other imaging test have real significance as a cause of the back pain. It should be noted that any nerve injuries that affect these tests may not be present for two to four weeks after symptoms begin.

Nerve conduction studies and electromyography are the electrodiagnostic tests most commonly performed.

Nerve Conduction Studies . To perform nerve conduction studies, surface electrodes are attached to the skin. Small electric shocks are then applied to measure the speed of nerve conduction.

Electromyography . To perform electromyography, a fine, sterile, wire electrode is inserted briefly into a muscle and the electrical activity is displayed on a viewing screen. Electromyography can be quite painful, and some experts question, in fact, whether it adds any valuable diagnostic information. They suggest it be limited to unusual cases or when other tests indicate that the condition is aggressive and may increase the risk for rapid, significant injury.

Other Tests

Blood and urine samples may be used to test for infections, arthritis, or other conditions.

Injecting a drug that blocks pain into the nerves in the back helps locate the level in the spine where problems occur.

A procedure called a facet block is also useful in locating areas of specific damage.

Provocative diskometry is a test that uses an injection of saline solution into the suspected disk to reproduce the pain, which is then followed by injection of an anesthetic to dull the pain.

• Review Date: 3/19/2007
• Reviewed By: Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital

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