A herniated disc (or disc herniation) is a condition that usually occurs in the lower back and is one of the leading causes of lower back pain as well as of leg pain or sciatica. Another name for this condition is a slipped disc or spinal hernia.
Disc herniation is usually a result of gradual deterioration of spinal disks. However, in a few cases, it can be triggered by trauma due to a blow to the back or a fall.
Although it can be present in some individuals with little or no discernible sign, the condition causes severe pain in some others. It can also cause numbness, muscle weakness or tingling sensations in the affected areas of the body. In extreme cases, victims of the condition may experience loss of reflexes or partial paralysis.
Despite its unpleasant and sometimes alarming symptoms, a herniated disc problem is usually manageable without resorting to surgery. Affected individuals can usually gain relief from its symptoms with modification of daily activities, pain medication and physiotherapy.
Your spine consists of 24 small bones, commonly known as vertebrae, stacked vertically.
The vertebrae are connected with each other in such a way as to create a canal (the spinal column) that contains your spinal cord and nerves carrying pain and other information between your brain and the rest of the body. The nerve roots branch out from the spinal canal via openings in the vertebrae to serve various parts of the body.
The lower back area that is the subject of pain for so many people consists of the last 5 vertebrae of the spine. This is the part of the spine in which most cases of disc herniation occur. It is also commonly known as the lumbar spine. The portion of the spine that runs behind the neck is called the cervical spine.
Although the vertebrae are stacked one on top of another, they are not in direct contact. Instead, they are separated by round flat rubbery discs that are each about a half inch thick. These intervertebral discs serve as shock absorbers between the vertebrae when you walk or run. Without them, the vertebrae would come into direct contact with each other and cause tremendous pain.
The disks have tough but flexible outer coverings (called annuli) but contain a soft jelly like material inside (known as the nucleus pulposus).
A disc located in the lumbar portion of the spine is also referred to as a lumbar disc while one in the cervical portion is known as a cervical disc.
A herniated disc forms when the outer shell of the disc starters to bulge due to pressure from the jelly like interior. This is usually the result of deterioration of the outer shell due to wear and tear, or it may be the result of traumatic damage to the shell.
Over time, the bulging of the disk results in pressure against the spinal cord and the nerve roots emerging from it.
As the jelly-like interior continues to exert pressure, it eventually pushes through the outer shell of the disk. The spinal cord and nerves therefore experience increased pressure.The nerve roots may also be irritated by the release of chemicals from the interior of the disk.
The pressure on and irritation of the spinal nerves can contribute to the pain, numbness and tingling that disc herniation sufferers experience. When it occurs in the legs, it is known as sciatica.
Disc Herniation Causes & Risk Factors
The damage to the outer shell of the intervertebral disk is usually the result of natural wear and tear on the spine as aging occurs. When this is the cause, the condition is referred to as degenerative disc disease.
A large part of this degeneration is the natural decrease in the water content of the discs as aging occurs. As this happens, the shell of the disc loses its flexibility. The discs also shrink and get closer together, reducing the space for the nerve roots to exit the spinal canal.
In a minority of cases, a herniated disc can occur suddenly as a result of a fall or blow to the back.
The factors that can increase the risk of disc herniation include:
Gender & Age – The condition tends to mainly affect men, and to appear between the ages of 20 and 50;
Lifting heavy loads using improper technique that places too much strain on the lower back;
Excess body weight can place extra stress on the back and contribute to disc herniation;
Remaining in a seated position for extended periods, especially when combined with poor posture;
Smoking – some research suggests that this can reduce the supply of oxygen to the intervertebral discs and increase the risk of herniation.
Symptoms Of A Herniated Disc
As mentioned above, many individuals may have disc herniation as evidenced by an imaging scan, yet feel no symptoms at all.
However, when symptoms are present they can include:
Lower back pain that may come and go every few days;
Sciatica, or a sharp pain that starts at the top of one leg, then shoots downward along the leg;
Numbness, weakness or tingling in the legs or lower back;
In severe cases, reduced bladder or bowel control. This can be evidence of a serious condition known as cauda equina syndrome that requires urgent medical attention.
To make a diagnosis, your doctor will probably review your symptoms and medical history with you and then conduct a physical examination.
The physical examination will likely include checking for muscle weakness and loss of sensation in the legs. Knee and ankle reflexes will also be evaluated as they can be affected by compression of nerve roots in the spinal canal.
Another important part of the physical exam would be a straight leg raise test. The doctor will ask you to lie on your back while he carefully lifts the leg in which you feel numbness or tingling, keeping your knee straight. Pain down the leg and below the knee is a reliable indicator of a herniated disk problem.
If the doctor is still unsure after the physical test, a magnetic resonance imaging (mri) test may be requested. It will provide imaging of the soft tissues of the back, and particularly of the intervertebral disks.
Once the doctor confirms a disc herniation, a treatment plan will be developed. The initial preference will lilley be for non surgical treatment:
A short period of bed rest (but not for a longer period, due to the risk of muscle atrophy)
Taking pain relief or non steroidal anti inflammatory medications;
Physical therapy to strengthen the lower back and abdominal muscles;
Cortisone injections near the affected nerves to reduce any inflammation that may be present.
If this approach is successful, the patient should have significant relief from herniated disc symptoms in around 3-4 months.
Should the conservative approach mentioned above prove to be unsuccessful, doctors may suggest a surgical approach. This is necessary only in a small minority of cases, however. In the overwhelming majority of cases, non surgical treatment is adequate.
The surgical treatment options considered may include:
Microdiskectomy – a procedure in which the herniated portion of the disk is surgically removed to reduce pressure on spinal nerves;
Complete removal of a herniated disc and the fusing together of the adjacent vertebrae
Before opting for the surgical route, be sure to discuss its implications thoroughly with the attending physician. Surgical intervention to treat a herniated disc involves several risks, including nerve injuries, infection, hematoma (internal bleeding) and damage to the sac covering and protecting the spinal nerves.
The existence of these risks makes the non surgical treatment option the preferable choice whenever it is feasible.