Herniated discs typically occur in the lumbar spine, the "small of the back" area. The lumbar spine is made of five separate vertebrae, which are separated by a cushion called a disc. The disc cushion is made of a soft spongy material that is contained within a very tough fibrous outer layer. A disc herniation occurs when the tough outer layer develops a weak spot and allows the inner spongy tissue to leak out.
The disc material typically leaks against a spinal nerve, causing both a chemical irritation and direct pressure on the nerve. The nerves in the lumbar spine travel to various places in the buttocks and legs, so the irritation of one of these nerves can cause leg pain, called sciatica.
Causes of Herniated Discs
About 2% of the general population experience herniated discs in the lumbar section of the back. They can happen to anyone at any time. In fact, many patients say they "just woke up and could not get out of bed" without any prior injury. However, there are certain factors associated with disc herniations, including heavy lifting, improper lifting techniques, stressful occupations and cigarette smoking.
Symptoms of Herniated Discs
Most patients report moderate levels of back pain prior to the onset of the leg pain that is present in almost any position. However, disc herniations can occur without injury, and even without back pain. The symptoms in some patients may include only leg pain or weakness. The specific location of leg pain and weakness depends on which nerve is irritated.
Treatment of Herniated Discs
Sixty to seventy percent of patients with lumbar disc herniations experience resolution of most symptoms within eight to twelve weeks using conservative treatments including bed rest, over-the-counter anti-inflammatory medication, physical therapy, and home exercise programs. For severe symptoms, a short course of narcotics or muscle relaxants may be used. A series of oral steroids or epidural steroid injections into the spine also may calm the inflammation of the nerves and provide temporary relief of the buttock and leg symptoms.
Only about 30 percent of patients with a disc herniation and sciatica will need a spine operation. However, those with loss of bowel or bladder function, major muscle weakness, and excruciating, uncontrollable pain may benefit from surgical intervention. A persistently symptomatic patient should not wait more than 12 weeks to consult with a surgeon, because after that time frame, the window of opportunity for benefit from spine surgery begins to narrow.