PCL 6- Diagnosis of sciatica

To help diagnose sciatica and pinpoint which nerves, if any are affected, the doctor will use these approaches:

1.) Medical History

The patient should be able to describe the back pain and its history in the following manner:

Frequency, duration, and nature of the pain

• When the pain occurs
• What triggered the pain (such as lifting a heavy object)
• Conditions that make the pain worse, such as coughing
• Other relevant symptoms, such as morning stiffness, weakness, or numbness in the legs
• Previous episodes of back pain
• Severity of the pain and how it affects the person's ability to perform everyday activities or work activities
• Any situation that relieves the pain
• Any history of injuries or accidents involving the neck, back, or hips
• Other medical conditions, such as arthritis or osteoporosis
• A patient should report any serious health problems, symptoms, and concerns that may raise a red flag for a more serious condition. These include:
• HIV infection or AIDS
• Pain that is persistently increasing in intensity and cannot be relieved
• Fever that is associated with the back pain
• Any new or worsening neurological symptoms, such as weakness in a specific part of the legs or feet
• History of cancer, or currently being treated for cancer
• Problems emptying the bowels or bladder, including incontinence
• Unexplained weight loss

Example:

A patient with sciatica due to lumbar disc herniation will present with

1. A sharp, burning, stabbing pain radiating below knee
2. Pain is localized, superficial, 'band like'.
3. Often associated with parasthesia
4. Usually there is substantial but incomplete relief with rest
5. Initially, pain felt in low back and buttock(s), but as disease progresses pain felt distally over dermatome.

2.) Physical signs

• Includes observation, palpation, determination of range of motion of spine, a root tension test (nerve stretch test) and evaluation of neurological status of lower limbs.
• Straight Leg Raising test (SLR) - Patient in supine position, lift each leg in turn at the hip, normally 80-90* hip flexion is possible. This test is positive with nerve root irritation at L4 or below.
• Lasegue's test-If the foot is returned to neutral position, and knee flexed, hip can be flexed further without pain, but the pain reappears when knee is then extended.
• The straight leg raising test stretches the L5 and S1 roots, and this test is regarded positive if leg pain is aggravated when the affected leg (SLR) or the contralateral leg (crossed SLR) is raised.
• Root tension tests are sensitive but unspecific as to the location and cause of nerve root irritation. SLR is sensitive, but unspecific, whereas crossed SLR is very specific, but its sensitivity is low.
• L4 root lesions may be accompanied by reduction of the knee jerk.
• Reflex testing is less useful in recurrent sciatica.
• Clinical examination is also recommended to include:

1) Testing of dorsiflexion strength of the ankle and the big toe, with weakness suggesting mainly L5 dysfunction.

2) Testing of ankle reflexes to evaluate S1 root dysfunction

3) Testing of light touch sensation in the medial (L4), dorsal (L5) and lateral (S1) aspects of the foot

The accuracy of neurological tests can, however, be improved by combining the tests (parallel testing)

3.)Imaging tests

If pain lasts longer than four weeks or is very severe, or there is another serious condition such as cancer, there are one or more imaging tests to help identity why the sciatic nerve is compressed and to rule out other causes for your symptoms.

These tests include:

• Spinal X-ray. Ordinary X-rays can't detect herniated disk problems or nerve damage. A spinal X-ray can help pinpoint the cause of sciatica.
• Magnetic resonance imaging (MRI). This is probably the most sensitive test for assessing sciatic nerve pain. Instead of X-rays, MRI uses a powerful magnet and radio waves to produce cross-sectional images of your back. Most MRI machines are large, tube-shaped magnets. During the test, you lie on a movable table inside the MRI machine.
• Computerized tomography (CT) scan. This test uses a narrow beam of radiation to produce detailed, cross-sectional images of your body. When CT is used to image the spine, you may have a contrast dye injected into your spinal canal before the X-rays are taken — a procedure called a CT myelogram. The dye then circulates around your spinal cord and spinal nerves, which appear white on the scan.

OTHER TESTS

• Discography: Since many people have evidence of disk degeneration on their MRI scans, it is not always easy to tell if the finding on this MRI scan explains pain the patient may be experiencing. Discography is a test that is used to help determine whether an abnormal disk seen on MRI explains someone's pain. When performed, it is generally reserved for patients who did not experience relief from other therapies, including surgery. This procedure requires injections into disks suspected of being the source of pain and disks nearby. It can be painful. There is controversy among physicians who take care of the spine regarding the usefulness of discography for making decisions about care, particularly surgery.

• 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.