What Is a Herniated Disc?
Many patients with back pain, leg pain, or weakness of the lower extremity muscles are diagnosed with a herniated disc, or rupture of the intervertebral disc of the spine. When this occurs, the cushion that sits between the spinal vertebra is pushed outside its normal position. A herniated disc would not be a problem so often if it weren’t for the spinal nerves that are very close to the edge of the intervertebral disc.
The intervertebral disc is a soft cushion that becomes more rigid with age. In a young individual, the disc is soft and elastic, but like so many other structures in the body (such as tendons and ligaments), as we age, the disc looses its elasticity and is more vulnerable to injury. In fact, even in individuals as young as 30, a MRI shows evidence of disc deterioration in about 30% of people.
When a herniated disc bulges out from between the vertebrae, the spinal nerves and spinal cord can become pinched and/or irritated. The material in the central part of the disc called the nucleus can cause irritation or inflammation of tissue when extruded from the disc. Often, the primary source of pain is from this inflammation and not from compression. There is normally a little extra space around the spinal cord and spinal nerves, but if enough of the herniated disc is pushed out of place, these structures may be compressed. Significant compression of nerves generally causes true numbness, muscle weakness, loss of reflexes which indicates that the nerves are damaged. Compression alone may not cause any pain at all.
What causes symptoms
of a herniated disc?
When the herniated disc ruptures and pushes out, the nerves may become trapped. A herniated disc may occur suddenly in an event such as a fall or an accident, or may occur gradually with repetitive straining of the lumbar spine. When a herniated disc occurs, the space for the nerve is diminished and irritation of the nerve results.
Common symptoms of
a herniated disc include
Paresthesias (tingling, numbness, or pins and needles)
Bowel or Bladder Problems
All of these symptoms are due to the irritation of the nerve from the herniated disc. By interfering with the pathway by which signals are sent from your brain out to your extremities and back to the brain, all of these symptoms can be caused by a herniated disc pressing against the spinal nerves.
How is the diagnosis
of a herniated disc made?
Most often, your physician can make the diagnosis of a herniated disc by physical examination. By testing sensation, muscle strength, and reflexes, your physician can often establish the diagnosis of a herniated disc.
A MRI is commonly used to aid in making the diagnosis of a herniated disc. It is very important that patients understand that the MRI is only useful when used in conjunction with examination findings. It is normal for a MRI of the lumbar spine to have “abnormalities,” especially as people age. Patients in their 20s may begin to have signs of disc wear, and this type of wear would be expected on MRIs of patients in their 40s and 50s. This is the reason that your physician may not be concerned with some MRI findings noted by the radiologist.
Making the diagnosis of a herniated disc, and coming up with a treatment plan depends on the symptoms experienced by the patient, the physical examination findings, and the x-ray and MRI results. Only once this information is put together can a reasonable treatment plan be considered.