Back pain can occur with or without leg pain, numbness, weakness or bowel or bladder problems. To learn more about your back pain, your doctor will do a preliminary physical examination that may confirm the findings above as well as possibly revealing other signs such as tenderness, abnormal reflexes, or pain with specific movements.

In order to determine the cause of your back pain, your doctor may order a work-up that can includes any of the following: an x-ray, CT scan, CT myelogram, MRI, bone scan, electrodiagnostic examination, discography, diagnostic injection, psychiatric evaluation, and/or functional capacity evaluation.

Back Pain Diagnostic Tests

X-rays.  X-rays may reveal bone defects such as fractures, but do not directly show soft tissues such as discs, muscles, ligaments and nerves.

Computer tomography (CT) scans.  CT scans are also excellent for showing bone fractures.  In addition, they can reveal defects in soft tissues such as discs, muscles, ligaments, and nerves. Not all abnormalities, however, translate into symptoms or problems. A study of 52 people without any symptoms showed that in those aged 40 years old and younger, 19.5 percent showed abnormalities such as herniated discs. Of those over 40 years old, one half showed abnormalities such as herniated discs, facet degeneration, or stenosis.

CT myelograms.  CT myelograms involve injecting dye into the spine then performing a CT scan. The dye helps to emphasize structures like tumors.

Magnetic resonance imaging (MRI).  MRIs are better than CT scans for detecting soft tissue abnormalities. MRIs, however, are not as accurate at showing bone abnormalities. As with CT scans, not all abnormalities shown by MRIs translate into symptoms or problems. In a study of 98 people without any symptoms, only 36 were completely normal. In fact, of those 50 years old and older, 67 percent were abnormal. In those 50 years old and younger, 27 percent were abnormal. Overall, 64 percent had a herniated disc despite not having any outward symptoms.

Bone scans.  Bone scans can be a good screening test for infections and cancers. By using a radioactive substance injected into the vein that shows up on the scan, bone scans are able to identify “hot” and “cold” areas. Hot areas have increased blood supply while cold areas have less. Different disease processes may appear either hot or cold.

Electrodiagnostic evaluation.  Similar to what an electrician does to check electrical circuits, electrodiagnostic evaluation tests the function of nerves. It is up to 14.5 percent of normal people, however, can show abnormalities on the examination. There are two parts to the electrodiagnostic evaluation. One portion is referred to as nerve conduction studies. During this part of the examination, an electric stimulus is applied to the nerve. The speed at which the stimulus travels and the amount of reaction (action potential) to the stimulus are measured. The second portion is referred to as the needle electrode examination. A needle electrode is inserted into different muscles and their electrical activity is recorded. After a nerve is injured, it takes about three weeks for injured nerves to exhibit abnormalities on the electrodiagnostic evaluation.

Discography.  Discography is controversial. It is often used in surgical planning by identifying painful discs. A provocative discogram involves injecting saline into the disc. An anesthetic discogram, as the name implies, uses an anesthetic or a substance that numbs nerves in the abnormal disc. In a provocative discogram, pain that reproduces the patient’s symptoms is considered positive while the disappearance of the pain is the positive response in an anesthetic discogram. A positive test means that the injected disc is likely to be what is causing your pain.

Diagnostic injection.  Diagnostic injections include nerve root blocks and facet blocks. An anesthetic (a substance that numbs the nerve) and steroids to decrease inflammation or swelling may be used. If the pain resolves with the injection, then the injected structure is likely causing your pain. Another form of injection is lysis of adhesions or the breaking up of abnormal sticking points between structures in the spine. Adhesions prevent the free movement of these structures. For example a nerve may not be able to glide freely in its canal, thus causing pain. Dissolving agents such as hyaluronidase are injected into the spine, lysing or breaking up these sticking points. This leads to improved gliding and decreased pain.

Psychiatric evaluation.  Psychiatric evaluation screens for emotional or mental illness that may affect the pain experience.

Functional capacity evaluation.  Functional capacity evaluation measures the amount of work or activity that you can perform. This is usually done by a physical therapist using machines to measure force and effort.