Let us Understand What is a Disc?
There are 33 vertebrae and 23 discs in spinal column. Disc is situated between upper and lower vertebrae in neck, thorax and lumbar spine.
Disc has inner soft nucleus pulposus oval in shape and outer annulus fibrosus. Nucleus pulposus is soft and lies in the center of the disc and is protected by annular layers of annulus fibrosis. There are no discs in sacrum and coccyx. Normal disc is made up of proteoglycan, collagen and water.
What is the Function of the Disc?
Body weight is transmitted through intervertebral disc. Disc functions as a close hydraulic system to absorb the shock of sudden movement and torque. Central nucleus pulposus is the soft jelly like substance which functions as hydraulic system to absorb the pressure and volume changes. Pressure and volume changes may occur often during movements and torques. Thus disc is often identified as shock absorber.
What are the Disc Diseases?
There are several disc diseases causing symptoms like pain. Disc disease includes bulge disc, disc herniation (rupture disc), disc sequestration, disc fragments, degenerative disc disease, foraminal stenosis and spinal stenosis.
What is Disc Herniation?
Nucleus pulposus initially protrudes into annulus fibrosus and pushes annulus fibrosus outward as a bulge called bulge disc. Continuous increased pressure within nucleus pulposus results into tear of annulus fibrosus. Nucleus pulposus now perforate or pierces through the outer layer of annulus fibrosus. Protrusion or herniation through annulus fibrosus beyond outside boundary results in herniated disc. Disc may herniate after spinal fusion surgery causing revision of same symptoms which was surgically treated.
Is Disc Protrusion and Ruptured Disc Same as Disc Herniation?
Yes, there are several terminologies used to described disc herniation. Disc protrusion is the term used to describe bulge disc and herniated disc. Disc protrusion into intact annulus fibrosus causes bulge disc and disc protrusion through ruptured annulus fibrosus is known as disc herniation. Bulge disc and herniated disc are more specific terms used to describe disc pathology. Similarly ruptured disc is also an alternative term used to define herniated disc.
What are the Symptoms of Disc Herniation?
Dermatomal distribution of the symptoms depends on level of disc involved in vertebral column. Herniation of disc in neck causes symptoms in neck and upper extremities. Herniation at the thoracic level causes symptoms in chest wall, and lumbar disc herniation causes symptoms in lower back and lower extremities. Abnormal sensory or motor nerve symptoms are spread through one or several nerves depending on site of pinch nerve either within foramina or spinal canal.
What is Pinch Nerve?
Pinch nerve is the term used to define pressure on nerve either at foramina causing foraminal stenosis or spinal canal causing spinal stenosis. Foraminal pinch nerve involves symptoms along single nerve on right or left side or bilateral. Large herniated disc within spinal canal can pinch several nerves causing cauda equina syndrome.
What are the Symptoms of Foraminal Stenosis?
Single spinal nerve comes out of spinal canal through a bony tunnel called foramina on right or left side. Protrusion of herniated disc into spinal canal causes closing of the tunnel or narrowing of the tunnel, which is also known as stenosis. Spinal nerve is compressed between herniated disk and surrounding bones. Initial symptom observed is pain as outer nerve fibers pinch or compressed are pain fibers. Later tingling and numbness become predominant sensory symptoms with pain as sensory fibers are compressed by narrowing of foramina. If the foramina is constricted because of huge herniation then motor fibers get compressed and motor symptoms are observed. Motor symptoms are weakness; difficulty to ambulate, and joint reflexes are absent.
What are the Symptoms of Spinal Stenosis?
Spinal stenosis is caused by herniation of the disc into spinal canal. Herniated disc occupies the space and narrowing of spinal canal depends on quantity of disk herniation. Spinal stenosis causes cauda equina syndrome.
What is Cauda Equina Syndrome?
Spinal nerves of lumbar level 2 to 5 and sacral 1 to 5 are bundled into group of spinal nerve called cauda equina. Multiple nerves of cauda equina lies below level second lumbar vertebrae. Any pressure over cauda equina between lumbar spines 2 to 5 causes pressure on several nerves of lower extremities. Bilateral symptoms such as electric shock like pain, burning shooting pain, tingling, numbness and muscle weakness of lower back and legs are often observed in cauda equina syndrome. Cauda equina syndrome also causes bladder and bowel problems.
What is Electric Shock like Pain?
Electric shock like unpleasant symptoms are seen over upper and lower extremities following pinch nerve at foramina or spinal canal.
What are the Bowel and Bladder Problems?
Urine and stool incontinence is the sign of severe pressure on lower spinal nerves in spinal canal and this condition is an emergency to prevent permanent nerve damage. Symptoms indicate severe compression of autonomic nerves, which lies within cauda equina.
What are the Most Useful Investigations to Diagnose Disc Herniation?
MRI or CAT scan study is useful in diagnosis of disk herniation. Nerve damage or injuries can be evaluated with nerve conduction study or myelogram study.
What are the Different Choices of Treatment?
Treatment choices are as follows:
- Microdiscectomy, percutaneous disc removal.
- Spinal Fusion.
Which are the Different Medications Used for Treatment of Symptoms Caused by Disc Herniation?
- Nonsteroidal Anti-inflammatory Medications such as Tylenol, Motrin, Naproxen and Celebrex.
- Muscle Relaxants - Flexeril, Soma, Robaxin and Skelaxin.
- Antiepileptic Analgesics - Neurontin and Lyrica.
- Antidepressants Analgesics - Elavil and Cymbalta.