Low Back Pain

Low back pain is extremely common. Almost every person will have at least one episode of low back pain at some time in his or her life. The pain can vary from severe and long term to mild and short lived. It will resolve within a few weeks for most people.

Anatomy

There are 24 vertebrae in three upper segments of the spinal column.

These three segments create three natural curves of the back: the curves of the neck area (cervical), chest area (thoracic), and lower back (lumbar). The lower segments of the spine (sacrum and coccyx) are made up of a series of vertebrae that are fused together.

The lower back is a complex area that connects the upper body (including the chest and arms) to the lower body (including the pelvis and legs). The lower back is composed of several vertebrae, disks of soft cartilage, muscles, joints, ligaments, and nerve tissue.

• Lumbar vertebrae - five cylindrical bones
   stacked one upon the other, connecting the
   upper spine to the pelvis

• Disks - act as shock absorbers between the
   vertebrae, and allow for spine movement

• Spinal cord and nerves - the "electrical
   cables," which travel through a central canal
   in the lumbar vertebrae, connecting the brain
   to the leg muscles

• Small joints - between vertebrae, they
   allow movement and provide stability

• Muscles and ligaments - provide strength
   and power, as well as support and stability

Magnetic resonance image (MRI) scan of the lumbar spine (side view).

The lower back provides the body with power and mobility, allowing such movements as turning, twisting or bending, as well as the strength to stand, walk, and lift. Proper functioning of the lower back is needed for almost all activities of daily living.

Cause

Doctors have many ideas about what causes low back pain, but no single explanation applies to everyone.

Low back pain may be related to aging of the disk. As a result of wear and tear on the spine, ligaments, and disks, a disk may begin to protrude or collapse and put pressure on the nerve root leading to a leg or foot, causing pain in those areas (sciatica).

The problem can be aggravated by associated conditions, such as narrowing (stenosis) of the canal or shifting of the vertebra (spondylolisthesis), one upon the other.

Low back pain is sometimes caused by:

• Excessive stress to the back, such as lifting something heavy

• Minimal movement, such as bending or reaching for something

• Arthritis of the spine

• Problems with tendons or ligaments in and around the spine

• Malpositioning of vertebrae

Occasionally, it happens with no cause.

Doctors do not know why some people with acute back pain go on to suffer from long term (chronic) low back pain. They also don't know why some people go on to feel quite well between episodes of severe pain.

Symptoms

The symptoms of low back pain vary in some ways and are similar in others. Most people find that reclining or lying down will improve their pain and after their initial severe episode, many will be able to rest at night without severe pain. Most people experience more severe pain when they bend over to pick something up. Some get relief from arching backward (extending the back).

Leg pain also can be part of the problem. The pain is most common in the back or outer side of the thigh, and can go all the way to the foot. Pain that goes to the foot is called sciatica because it is pain that follows the course of the sciatic nerve. Sciatica is often made worse by coughing or sneezing.

With an acute episode, back pain can be very severe for a few days or a week and then will often improve. By 2 weeks to 4 weeks, most people are much better. The length of time between episodes varies greatly from person to person, as does the length of each episode, the intensity of each episode, and how well each individual copes with the pain.

Diagnosis

See your doctor to diagnose low back pain. Tell him or her your complete medical history. The physical examination is often completely normal except for pain with motion. The doctor checks for:

• Evidence of nerve problems. The doctor evaluates strength, sensation
   and reflexes. He or she may ask you to move your spine to see how limited
   the motion is.
• Poor blood circulation. Although not related to the spine, poor blood
   circulation can lead to back pain. Tell the doctor what motions or positions
   hurt and what helps relieve the pain.

X-rays
X-rays and other imaging studies are typically not used in determining the cause of short-term (acute) back pain. When X-rays are obtained, they are often normal or they show an abnormality that may not be related to the pain. For instance, it is very common to see some disk degeneration in X-rays of people with back pain. But it is also very common to see it in people who do not have back pain. It is difficult to tell whether the degeneration is actually the cause of the pain. The same is true for magnetic resonance imaging (MRI) and computed tomography (CT) scans.

Many X-ray findings are considered nonspecific -- they may or may not be related to the pain. Some nonspecific findings are disk space narrowing, spurring, spina bifida occulta (incomplete formation of the lamina and spinous process), mild scoliosis, and a decrease in lumbar lordosis (the normal curvature of the spine when viewed from the side). In addition, disks are not visible on X-ray -- only the disk spaces.

X-rays and other imaging studies are more likely to be helpful when low back pain does not get better on its own after a few weeks or when a person has evidence of more severe problems. Tell the doctor if you have a history of a previous cancer, fevers or chills that may be caused by an infection, or a significant trauma like a fall or car accident that may have caused a fracture.

Significant weakness on physical examination could also indicate problems. If a person is having trouble controlling their urine or bowels, the doctor will usually order X-rays and other studies more quickly.

MRI (Magnetic Resonance Imaging)

MRI is often the next imaging test ordered if the physician feels it is indicated. With MRI, the doctor can see the disks and the nerves. He or she can see the level of degeneration of the disks and whether there is any material that has gone outside of the normal confines of the disk (herniation). MRI is also very good at showing infections, tumors, and fractures.

Although an MRI scan can sometimes help the doctor determine the source of a back problem, it also often shows nonspecific findings.

Additional Diagnostic Tests
Other tests your doctor may conduct to determine the cause of your back pain:

• CT (computed tomography) scans are similar to three-dimensional
   X-rays.

• Bone scans look for areas of possible infection, tumor, or fracture.

• Electromyography [EMG] and nerve conduction velocity [NCV] tests
   see how well the nerves in the arms and legs conduct electrical signals.

• Bone density studies may be ordered if osteoporosis is a concern.
   Osteoporosis by itself should not cause back pain, but fractures due to
   osteoporosis can.

Treatment

Treatments for low back pain are multiple and varied.

Nonsurgical Treatment

Counseling and Education
At times, counseling and education about the problem to ease a person's anxiety is enough to make it tolerable until the episode resolves.

Rest
A few days of rest can often calm the pain down as well. Prolonged bed rest (more than 2 days to 3 days) is no longer generally recommended for people with low back pain.

Medication
Medications such as nonsteroidal anti inflammatory drugs (NSAIDS) or acetaminophen can be helpful. Occasionally, stronger medications such as muscle relaxants and narcotics are used for a short period.

Braces
Although there is minimal scientific evidence of their effectiveness in treating low back pain, back braces are commonly used. Most common is a corset type brace that can be wrapped around the back and abdomen. People who use corset type braces sometimes report feeling better supported and more comfortable.

Passive Modalities
Passive modalities include the application of heat or cold, massage, ultrasound, electrical stimulation, traction, and acupuncture. How long the benefit will last or what the chances are of receiving benefit from any of these treatments is not completely known.

Spinal Manipulation
Another form of passive treatment is spinal manipulation. There are many different practitioners of spinal manipulation, each with their own style of manipulation. This has also at times improved symptoms of low back pain.

Injections
The most commonly used injections are local anesthetic and/or steroids. They are usually given either in the area that is believed to be the source of the pain, such as into a muscle or facet joint, or around the nerves of the spine (an epidural or nerve root injection). Injections are occasionally placed into the disk, but this is done far less frequently.

Exercise and Stretching
Exercising to restore motion and strength to a painful lumbar spine can be very helpful in relieving pain. Although there is controversy as to which are the most effective spine exercises, it is generally agreed that exercise should be both aerobic (aimed at improving heart and lung function) and specific to the spine. Aerobic exercises include walking, jogging, swimming, and bicycling.

Proper Lifting Technique
Instruction in lifting techniques can be helpful as well. Improperly bending over to lift can cause a large increase in strain on the low back. Proper lifting keeps the back straight while you bend with the knees.

Surgical Treatment

Indications

Surgery for low back pain should only be performed when a number of conditions have been met.

• The first condition is that nonsurgical treatment options have been tried
   and have failed. For example, surgery should not be done if an exercise
   program is effective but the person does not want to do it.
• The second condition is the surgeon believes the patient has a good chance
   of having a successful result with surgery. For example, a person with severe
   degeneration at one level of their spine and normal findings at the other levels
   may be a good candidate for successful surgery.
• Another consideration that can influence a successful surgical outcome is
   stress. Low back pain, like many other pain problems, can be worse during
   times of stress. It may not be a good idea to commit to an operation like this
   when there are other major stressful events going on in one's life.
   Occasionally, the back problem can become more tolerable once the stress is
   reduced.
• The third condition is that the patient must decide whether he or she is having
   enough of a problem to undergo an invasive procedure that is not guaranteed
   to work.

Options

• Spinal Fusion. Historically, the most commonly performed surgical procedure
for low back pain has been spinal fusion. There are a variety of ways this is
done, but the basic idea is to take the painful segment of the spine and get
it to become a solid piece of bone. This will eliminate motion and, in theory
at least, if it does not move, it should not hurt.

  This can be done through the back (posterior approach) or through the front
(anterior approach), or sometimes both ways. Spinal fixation of some sort is
often combined with some form of bone graft or bone substitute. Bone graft
can either be obtained from another part of the skeleton such as the pelvis
(autograft) or be donated bone (allograft) that is processed and used in a
spinal fusion.

  The results of spinal fusion for low back pain vary. A good result is a decrease
in pain. It is very rare for a patient to be completely pain-free after spinal
fusion. Full recovery can take more than a year.

• Disk Replacement. A newer technique that has recently been introduced in
   the United States is disk replacement. The procedure involves removing the
   disk and replacing it with artificial components, similar to what is done in the
   hip or the knee.

  The goal of disk replacement is to allow the segment of the spine keep some
flexibility and thereby maintain more normal motion. The recovery time may be
shorter than with spinal fusion because the bone does not have to solidify.

  Although disk replacement has been used in Europe for years, it has only
recently been used in the United States. Early results are promising. Currently,
disk replacements are done through an anterior approach and are primarily
done on the lower two disks of the lumbar spine.

Prevention

Low back pain caused by lifting can be prevented by using proper lifting techniques and by exercising regularly to improve muscle strength and overall physical condition.

The normal effects of aging that result in loss of bone mass and decreased strength and elasticity of muscles and ligaments can't be avoided.

Illustration of proper lifting.

However, the effects can be slowed by:

• Exercising regularly to keep the muscles of the back strong and flexible

• Using the correct lifting and moving techniques

• Maintaining a proper body weight; being overweight puts a strain on the
back muscles

• Avoiding smoking

• Maintaining a proper posture when standing and sitting; don't slouch

Research on the Horizon

A great deal of research is being performed to help doctors understand and treat low back pain. Some of the more exciting research includes new forms of disk replacement that some day may be injectable, and research into gene therapy that may some day allow doctors to alter the aging process of the spine.