Lumbar disc pain is one of the most difficult and irritating health conditions that can occur in anybody. They not only cause a lot of pain, but they also cause a great deal of disability. Lumbar pain is a symptom of an underlying condition.1 Usually, this is caused by the degeneration of the lumbar discs. A lumbar disc is a disc located in the spine in the lower back. Spinal discs act like cushions separating each set of bones in the back. These spinal discs are extremely important, because they act as shock absorbers upon movement and they also prevent the bones from rubbing against each other, which can be very painful. Each disc comprises of a strong outer covering (annulus) and a soft jelly center (nucleus). The two most common problems that may occur with a lumbar disc are bulging disc and degenerative disc disease.
Degenerative disc disease is the wear and tear of the lumbar intervertebral discs due to natural aging process.2 When the jelly in the center of the disc dehydrates (loses moisture) this causes degenerative disc disease. DDD occurs with age and overuse of the discs causing discs to flatten and apply pressure on the nerves. This condition is called discogenic back pain or lumbar disc pain.
When the outer covering of the disc becomes weak, it causes the jelly in the center of the disc to protrude into the weak area causing a disc bulge also known as herniated disc or a slipped disc.3 This causes extreme pain because the spinal nerves are situated directly behind the spinal discs, and when a disc bulges, it applies pressure on one of these nerves. These spinal nerves are very sensitive and cause severe pain when compressed. As the nerves control everything in the body, the parts of body controlled by the affected nerve will also be affected.
The symptoms that occur with lumbar disc conditions will include lower back pain, pain in the hips and legs, weakness in the legs, numbness in the feet, sciatic pain (pain shooting down the leg), as well as bowel and bladder problems. In case of, bulged disc, the symptoms will get worse with certain activities or they will remain the same throughout the day.
Lower back pain is a common complaint in the elderly people.4 Almost 90% of episodes of lower back pain are self-limiting and resolve within few weeks on their own. There are many causes of back pain. Treatment depends on the cause of the pain. The underlying cause should be identified and serious causes of lower back pain should be ruled out. Some of the common causes of back pain are strained back muscles, herniated discs, spinal stenosis and other conditions. One of the most common causes of back pain is degeneration of the discs.
As degenerative disc disease is a form of arthritis and it gradually develops over a period of time. The treatments available for any lumbar disc condition are very similar. Most physicians will recommend medications like muscle relaxants and pain killers, physical therapy, pain injections such as cortisone and epidurals, and surgery as a last resort.
Indications Suggesting A Serious Cause For Lower Back Pain Are As Follows:
Age younger than 20 years or older than 50 years, major trauma or accident, history of cancer or recent infection, increasing pain worse at night, changes in bowel or bladder function and progressive neurologic deficit or weakness.
Pathophysiology of Lumbar Disc Pain
Back pain is the most common complaint in people having symptomatic lumbar disc disorders. Other symptoms may include referred leg pains, radicular pains, sensory alterations and weakness of legs. As neurologic deficits are generally localized in L5 or S1 nerve roots, concentration should be more on these dermatomes and muscle groups. Some of most valuable diagnostic studies are myelography, CT, post-myelogram CT, and MRI. Initially, people are managed using conservative measures by physical therapy and reduction of activity and then gradually start increasing mobility and exercises. These conservative measures are beneficial for most people. If people do not improve with conservative measures and start having neurologic dysfunctions, then surgical treatment is considered. Measures like weight control, diligent exercise, and correction of posture go a long way in helping reduce frequency and severity of recurrent disc herniation and pain. Just like other parts of body, every intervertebral disc has nerve supply. Discs are made up of two parts that is annulus fibrosus and nucleus pulposus. Nucleus pulposus does not have nerves; however, the outer third of annulus fibrosus has nerve fibers. Internal Disc Disruption is another type of discogenic disorder caused when disc gets torn allowing nucleus pulposus to protrude outward. When this happens, a chemical called proteoglycan is released from nucleus pulposus. This chemical causes irritation to annular nerves leading to inflammation and pain. In some cases, patients may have annular tear but they may have no symptoms.
Lumbar disc disease is caused by normal degenerative changes that occur with aging.4 The lumbar spine consists of motion segments. Each motion segment has two vertebral bodies, intervertebral disc and two facet joints. Intervertebral disc acts as the cushion or “shock absorber,” of the spine. Intervertebral disc is mostly made up of water which gives it its cushion-like properties. As people age, intervertebral disc loses some of this water/moisture content causing the outer layers of the disc to develop cracks or tears leading to lower back pain. When the outer layer of the disc tears and the disc loses its normal water content, it causes reduction in its ability to act as a cushion or a shock absorber for the burden which the spine has to bear. As the time goes, it causes the discs to collapse and leads to degenerative changes in both the vertebral bodies and the facet joints of the spine. This condition is known as degenerative disc disease. As the degenerative changes increase it leads to destruction of the ligaments and other soft tissues of the spine causing segmental instability. This further increases pain, which occurs with the loss of normal structural stability of the spinal segments.
Etiology And Risk Factors of Lumbar Disc Pain
The exact cause lumbar disc pain is not well known. The most common cause is degenerative lumber discs. Lumbar disc degeneration is a part of the normal aging process. Many a times the degenerative discs may not cause any symptoms. Most patients with discogenic back pain improve with time and treatment. Lumbar disc disease is also known as lumbar spondylosis. The three main processes that make up lumbar disc disease are internal disc disruption, degenerative disc disease and segmental instability. Lumbar disc disease is caused by normal degenerative changes that occur with aging. The lumbar spine consists of motion segments. Each motion segment has two vertebral bodies, the intervertebral disc and two facet joints. The intervertebral disc acts as the cushion or “shock absorber,” of the spine. The intervertebral disc is mostly made up of water which gives it its cushion-like properties. As people age, the intervertebral disc loses some of this water/moisture content causing the outer layers of the disc to develop cracks or tears leading to lower back pain. When the outer layer of the disc tears and the disc loses its normal water content it causes reduction in its ability to act as a cushion or a shock absorber. As the time goes, it causes the discs to collapse and leads to degenerative changes in both the vertebral bodies and the facet joints of the spine. This condition is known as degenerative disc disease. As the degenerative changes increase, it leads to destruction of the ligaments and other soft tissues of the spine causing segmental instability. This further increases pain, which occurs when there is a loss of the normal structural stability of the spinal segments.
Signs And Symptoms of Lumbar Disc Pain
Disc degeneration causes lower back pain. Usually discogenic pain occurs with activities, which increase pressure in intervertebral discs like sitting, bending forward, coughing etc. All these can increase lower back discogenic pain. Low back discogenic pain may also be accompanied by leg pain due to pinched nerve in low back (radiculopathy) especially when sitting, standing or with ambulation. Lumbar disc pain is generally a chronic condition. Patients with lumbar disc disease usually develop symptoms of chronic lower back pain between the ages of 20 and 50 years. Pain increases with sitting or bending forward with localized tenderness in the lower back. The symptoms worsen as the degenerative changes in the spine progress from internal disc disruption to degenerative disc disease to segmental instability. Internal disc disruption causes deep ache in the low back that increases over time. Any type of motion or activity increases the pain. As the condition progresses, degenerative disc disease pain occurs in the low back along with pain in the back of the buttocks and thighs. Segmental instability leads to increase in pain with radiation down the lower extremities. This pain further increases with movement and walking.
Treatment for Lumbar Disc Pain
Conservative or Nonsurgical Treatment for Lumbar Disc Pain
- Rest: Sometimes pain is relieved if the patient takes adequate rest.5
- Medications: Anti-inflammatory drugs like ibuprofen (Motrin, Advil) or naproxen (Aleve), muscle relaxants, such as cyclobenzaprine (Flexeril), anti-depressants and opioids are helpful in relieving pain.
- Physical Therapy (PT) also helps in pain relief.
- TENS Unit and massage in combination with stretching and strengthening exercises are often beneficial for pain relief in degenerative disc diseases.
- Spinal Injections: Corticosteroid injections with anesthetic are injected into facet joints or around nerves of back. These help in controlling back and radicular leg pains.
- Bracing is helpful in supporting back and limiting movement.
- Alternative Therapies such as acupuncture, hydrotherapy, magnet therapy and chiropractic may also be helpful in some patients.
- Lifestyle Modifications like controlled weight loss, stopping smoking, and increased physical activities help in maintaining the spine healthy.
Surgical Treatment for Lumbar Disc Pain
Surgery is considered when patients do not respond to conservative treatment. Some of the surgical options include:
- Lumbar Decompression: Lumbar decompression is removing a portion of the bone from the back of the spinal column to increase the space for the nerves exiting the spinal cord and thus relieving the pressure on the nerves and the associated pain.
- Lumbar Fusion: Lumbar fusion can be done from either the front through the abdomen or through the back, or both. This is decided by the surgeon after doing a preoperative analysis.
- Lumbar Disc Replacement: Lumbar disc replacement is another treatment option for lumbar disc disease. This involves removing all intervertebral discs as in a spinal fusion and inserting an artificial disc. The advantage of this surgery is that the patient is able to retain almost normal motion of the spine, but this can only be done in cases of solitary disc disease.
Investigations for Lumbar Disc Pain
- Medical history and physical examination.
- Discogram is the primary test used to diagnose discogenic back pain. This involves placing a needle into the affected disc and injecting a small amount of contrast dye into the disc. The discogram provides information on the structure of the disc as well as the source of the pain.6
- MRI of the lumbar spine. As disc degeneration is a part of normal aging, MRIs may also show abnormalities in patients having no symptoms.
- CT scans.
- Blood tests can be done for further evaluation if there is any suspicion of infection, tumor or inflammatory disorder.
- EMG (electromyogram).
- Nerve conduction studies.