Diagnosing Disc Problems

A medical diagnosis (also known as a "clinical diagnosis") focuses on determining the underlying cause of a patient's back or neck pain, nerve pain, or other symptoms. There are four steps to arriving at a clinical diagnosis for a pinched nerve or disc pain:

  1. Physical examination. Depending on the patient’s symptoms, a physical exam may include one or more of the following tests:
    • Nerve function in certain parts of the leg or arm. This test involves tapping specific areas with a reflex hammer. If the patient has little or no reaction it is possibly indicative of a compressed nerve root in the spine.
    • Muscle strength. In order to get a better understanding of whether the spinal nerve root is compressed by a herniated disc, the doctor will likely conduct a neurological exam to assess muscle strength. The doctor may also ask the patient to partially undress in order to view the muscles, particularly to determine if there is muscle atrophy, twitching, or any abnormal movements.
    • Pain with palpation or motion. Palpating (touching) certain structures can give some idea of what really is generating pain. For example:
      • Pain over the sacroiliac joint—at the very bottom of the spine—to palpation may indicate the patient has sacroiliac joint dysfunction.
      • Pain with straightening the leg can be indicative of a pinched nerve.
      • Pain with pressure on the low back may indicate pain from a degenerative disc.
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  1. Review of specific symptoms. A complete review of symptoms will include the location of the pain, a description of how the pain feels (such as searing vs. dull or achy) , and whether certain activities, positions, or treatments make the pain feel better or worse.
  2. Review of medical history. A full medical background is important to rule out (or identify) other possible conditions that may cause the patient's pain. The history includes information such as any recurring health problems, previous diagnoses, past treatments and surgeries, reactions to those treatments, current medications, family history of illness, and any other health concerns.
  3. Diagnostic tests. After forming an opinion on the cause of the patient's pain, a diagnostic test may be ordered to confirm the disc problem and/or to gain additional information, such as the location of a herniated disc and impinged nerve roots. Diagnostic tests may include:
    • CT scan. Computerized tomography (CT) scans work like X-rays in that an X-ray beam is shot through the body, with a computer reformatting the image into cross sections of the spine.
    • MRI scan. Magnetic Resonance Imaging (MRI) allows doctors a sensitive and accurate assessment of the spinal nerves and anatomy, including disc alignment, height, hydration, and configuration.
    • Discogram. If surgery for disc pain is considered, some practitioners may recommend a discogram with the goal of confirming which disc is painful. In this test, radiographic dye is injected into the disc, with the belief that a patient is suffering from disc pain (degenerative disc disease) if the injected dye recreates the normal pain. This test is controversial as to whether or not it is a valid, accurate test, and many doctors do not use discography except in rare situations.

MRI is not a medical diagnosis

Lumbar herniated disc. Click to enlarge

It is important to note that the test findings on an MRI scan, or other diagnostic tests, are not in and of themselves a diagnosis of a herniated disc or degenerated disc. Many people over the age of 30 will have some level of a disc problem, but few will have pain associated with it.

Quite simply, a patient's physical exam findings and symptoms need to match the MRI or other test findings to arrive at an accurate medical diagnosis.

Only then can an effective treatment plan for the patient be prescribed, whether that entails treating a pinched nerve from a herniated disc, disc pain from a degenerative disc disease, or some other condition.

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