The spine consists of individual vertebra which are stacked on top of each other to form a support structure which can carry the weight of the body and give us sufficient flexibility. The neck area known as the cervical spine has seven vertebra segments, the part of the spine in the chest known as the thoracic spine has twelve vertebra. The part of the spine located in the lower back, or the lumbar spine, has five vertebra and the sacrum or the part of the spine below the last lumbar vertebra, (is the one that) forms the posterior wall of the pelvis that consists of five vertebra fused together.
Each vertebra is composed of solid bone which supports the bulk of the weight, and the pedicle and lamina which contains the spinal cord and the spinal nerves surrounding the spinal canal. The disc is the soft, flat circular structure which separates one vertebral body from the other. This disc acts as a shock absorber and has a relatively hard shell that is soft from the inside. With age the disc may experience degenerative changes: it may start to dry up, thin out and cracks may develop in the shell or the annulus. Consequently, the soft material from inside the disc escapes or herniates another reason for back pain called a disc herniation.
In the spaces between the vertebra on either side, pairs of spinal nerves pass through spaces between the vertebra known as the intervertebral foramen.
From the neck, there are 3 pairs of nerves in the upper part which go to the back of the head while the lower 5 nerves go to the arms. There are 12 pairs of nerves in the Thoracic spine that supply the chest wall and the abdomen. The nerves that supplies the legs, buttocks and the sphincters (for bowel and urine control) are found in the Lumbar or Sacral spine segment.
Disc herniation can be very painful and unbearable. A herniation of the disc toward one side may compress a spinal nerve against the bone of the intervertebral foramen. In this case the pain will shoot down or radiate to the limb, specifically the arm in a case of a cervical or neck disc herniation or the leg in a case of a lumbar disc herniation. Continued pressure will damage the nerve and weakness of the limb will atrophy or decrease in the mass of the muscle making movement slower.
If the crack in the shell or the annulus is not complete and the disc material does not escape but just bulges out like a tire which has curb damage, then it is called a disc bulge. Small disc bulges and small disc herniations are fairly common with the normal wear and tear associated with age. Though seen on an MRI, this does not mean that they are necessarily the cause of the pain. The pain can be due to the powerful muscles in the back that get stiff and muscle fibers may be damaged due to strain, causing painful spasms. This pain may also radiate down into the leg.
Often the pain from the herniated disc may radiate down a limb even if it is not compressing a nerve. Arthritis develops in the facet joints or the small joints, one on either side which supports one vertebra over the other. The disc is in the front end of the vertebral column and the facet joints provide support in the back. The pain from arthritis of the facet joints can also cause the pain to radiate down into the limbs.
Confirming what is causing the back pain usually requires performing specific tests of nerve function. Nerve Conduction Studies (NCS) and Electromyography (EMG) testing are procedures which evaluate how well the nerves of the wrist carry electrical signals. This information can help determine the extent of nerve damage (if any) and how best to treat the condition.
A very small percentage of disc herniations may require surgery. Specifically herniations which are causing constant pressure on the nerves going to the limbs cause progressive weakness.
In some cases, large central cervical disc herniations, which are discs that herniate to the front instead of the sides, can compress the spinal cord in the neck area causing weakness of both the arms and the legs.Additionally, large central disc herniations in the lumbar spine may compress the entire bundle of nerves which goes to the legs, and may cause weakness of both legs that may require surgical remedies.
Dr. Mir can review your MRI with you, take your history and may be able to tell by examining you if a disc bulge or herniation is in fact the cause of the pain or is an incidental or chance finding. If the pain is from facet arthritis or back sprain, Dr. Mir can recommend what course of action is the most beneficial for you. A neurologist is the best equipped and trained to help you determine if you need a referral to neurosurgery.
If you have persistent signs and symptoms that might be due to a Pinched Nerve that interfere with your normal activities including sleep, call your doctor’s office to schedule an appointment with Dr. Mir.