Herniated Discs: Definition, Progression, and Diagnosis
What are a Herniated Discs?
Herniation of the nucleus pulposus (gel-like substance) occurs when it breaks through the anulus fibrosus (tire-like structure) of an intervertebral disc (spinal shock absorber).
Herniated discs occurs most often in the lumbar region of the spine. This is because the lumbar spine carries most of the body's weight. People between the ages of 30 and 50 appear to be vulnerable because the elasticity and water content of the discs decreases with age.
The progression to an actual hernatied discs varies from slow to sudden onset of symptoms. There are four stages:
- disc protrusion
- prolapsed disc
- disc extrusion
- sequestered disc
Stages 1 and 2 are referred to as incomplete, where 3 and 4 are complete herniations. Pain resulting from herniated discs may be combined with a neurological deficit. The deficit may include tingling, numbness, weakness, reflex loss, and/or more. These changes are caused by nerve compression created by pressure from interior disc material.
The extremities affected are dependent upon the vertebral level at which the herniated discs occurred. Consider the following examples:
Pain in the neck, shoulders, and arms
Pain radiates into the chest
Pain extends into the buttocks, thighs, legs
Cauda Equina Syndrome occurs from a central disc herniation and is serious requiring immediate surgical intervention. The symptoms include bilateral leg pain, loss of perianal sensation (anus), paralysis of the bladder, and weakness of the anal sphincter.
Diagnosis of Herniated Discs
The spine is examined with the patient laying down and standing. Due to muscle spasm, a loss of normal spinal curvature may be noted. Radicular pain (inflammation of a spinal nerve) may increase when pressure is applied to the affected spinal level.
A Lasegue test, also known as Straight-leg Raising Test, is performed. The patient lies down, the knee is extended, and the hip is flexed. If pain is aggravated or produced, it is an indication the lower lumbosacral nerve roots are inflamed.
Other neurological tests are performed to determine loss of sensation and/or motor function. Abnormal reflexes are noted as these changes may indicate the location of the herniation.
Radiographs are helpful, but Computed Axial Tomography (CAT) or Magnetic Resonance Imaging (MRI) provides more detail. The MRI is the best method enabling the physician to see the soft spinal tissues unseen in a conventional x-ray.
Radiographic Evidence of Herniated Discs
The findings from the examination and tests are compared to make a proper diagnosis. This includes determining the location of the herniation so treatment options can be reviewed with the patient.