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Friday, March 7, 2014
A thorough medical history and physical exam can usually identify any dangerous conditions or family history that may be associated with back pain. Your doctor may ask you about:
The physician will examine the back and conduct neurologic tests to determine the cause of pain and appropriate treatment. Blood tests may also be ordered. Imaging tests may be necessary to diagnose tumors or other possible sources of the pain.
A variety of diagnostic methods are available to confirm the cause of back pain:
X-ray Imaging: includes conventional and enhanced methods that can help diagnose the cause and site of back pain. A conventional x-ray, often the first imaging technique used, looks for broken bones or an injured vertebra. A technician passes a concentrated beam of low-dose ionized radiation through the back and takes pictures that, within minutes, clearly show the bony structure and any vertebral misalignment or fractures. Tissue masses such as injured muscles and ligaments or painful conditions such as a bulging disc are not visible on conventional x-rays. This fast, noninvasive, painless procedure is usually performed in a doctor's office or at a clinic.
Discography: involves the injection of a special contrast dye into a spinal disc thought to be causing back pain, as well as at least one other normal disc to act as a control The dye outlines the damaged areas on x-rays taken during the injection. During the injection, the specialist carefully observes whether each disc injection triggers the patient's usual pain or not, in hopes of identifying the source of the person's pain. Because it is more invasive, and causes discomfort, this procedure is often reserved for patients who are considering lumbar surgery and whose pain has not responded to conventional treatments.
Myelography (Myelogram): Myelograms also enhance the diagnostic imaging of an x-ray. In this procedure, the contrast dye is injected into the spinal canal, allowing spinal cord and nerve compression caused by herniated discs or fractures to be seen on an x-ray. The most information can often be obtained by adding a CT scan (see below) once the dye has been injected. This study, a "CT-myelogram", is often used to replace or supplement MRI scans (see below).
Computerized tomography (CT): is a quick and painless process used when disc rupture, spinal stenosis, or damage to vertebrae is suspected as a cause of back pain. X-rays are passed through the body at various angles and are detected by a computerized scanner to produce two-dimensional slices (1 mm each) of internal structures of the back. This diagnostic exam is generally conducted at an imaging center or hospital. While some basic information about the discs, nerves, and spinal canal can be inferred from a CT scan, it is really most reliable for diagnosing problems with the bones. In most circumstances, an MRI or CT-myelogram is needed to evaluate the nerves and/or discs.
Magnetic resonance imaging (MRI): is used to evaluate bone degeneration or injury, or disease in tissues and nerves, muscles, ligaments, and blood vessels. MRI scanning equipment creates a magnetic field around the body strong enough to temporarily realign water molecules in the tissues. Radio waves are then passed through the body to detect the "relaxation" of the molecules back to a random alignment and trigger a resonance signal at different angles within the body. A computer processes this resonance into either a three-dimensional picture or a two-dimensional "slice" of the tissue being scanned, and differentiates between bone, soft tissues and fluid-filled spaces by their water content and structural properties. This noninvasive procedure is often used to identify a condition requiring prompt surgical treatment. MRI provides outstanding detail of problems with discs, nerves, spinal cord, and ligaments, and also immediately identifies tumors and infections. People with pacemakers, certain other metallic medical implants, and shrapnel or bullet fragments may not have an MRI. The technician performing the MRI will ask questions about these issues. In many places, "open MRI" scans are available. These machines do not require the patient to squeeze into such a small enclosed space, and therefore may be easier for very obese or very claustrophobic (frightened of small, enclosed spaces) people to tolerate. However, these "open MRI" or "open magnet" scans generate a much weaker magnetic field, and therefore the quality and resolution of the images generated are often poor, which may occasionally impair your health care provider's ability to diagnose your condition accurately.
EMG and EP: Electrodiagnostic procedures include electromyography (EMG), nerve conduction studies, and evoked potential (EP) studies. EMG assesses the electrical activity in a nerve and can detect if muscle weakness results from injury or a problem with the nerves that control the muscles. Very fine needles are inserted in muscles to measure electrical activity transmitted from the brain or spinal cord to a particular area of the body. With nerve conduction studies the doctor uses two sets of electrodes (similar to those used during an electrocardiogram) that are placed on the skin over the muscles. The first set gives the patient a mild shock to stimulate the nerve that runs to a particular muscle. The second set of electrodes is used to make a recording of the nerve's electrical signals, and from this information the doctor can determine if there is nerve damage. EP tests also involve two sets of electrodes - one set to stimulate a sensory nerve and the other set on the scalp to record the speed of nerve signal transmissions to the brain.
Bone scans: are used to diagnose and monitor infection, fracture, or disorders in the bone. A small amount of radioactive material is injected into the bloodstream and will collect in the bones, particularly in areas with some abnormality. Scanner-generated images are sent to a computer to identify specific areas of irregular bone metabolism or abnormal blood flow, as well as to measure levels of joint disease.
Thermography: involves the use of infrared sensing devices to measure small temperature changes between the two sides of the body or the temperature of a specific organ. Thermography may be used to detect the presence or absence of nerve root compression.
Ultrasound imaging: also called ultrasound scanning or sonography, uses high-frequency sound waves to obtain images inside the body. The sound wave echoes are recorded and displayed as a real-time visual image. Ultrasound imaging can show tears in ligaments, muscles, tendons, and other soft tissue masses in the back.
Source: National Institute of Neurological Disorders and Stroke - Low Back Pain Fact Sheet
Many research studies are underway to help us learn about spine and back conditions. Would you like to find out more about being part of this exciting research? Please visit the following links:
Last Reviewed: Oct 12, 2011
David J Hart, MD
Associate Professor of Neurosurgery
School of Medicine
Case Western Reserve University