Lower Back Pain

• The large nerve roots in the low back that go to the legs and arms may be irritated
• The smaller nerves that innervate the spine in the low back may be irritated
• The large paired lower back muscles (erector spinae) may be strained
• The bones, ligaments or joints may be injured
• The intervertebral disk may be injured

It is important to note that many types of low back pain have no known anatomical cause, but the pain is still real and needs to be treated. However, usually low back pain can be linked to a general cause (such as muscle strain) or a specific and diagnosable condition (such as degenerative disc disease or a lumbar herniated disc).

Types of lower back pain that indicate a surgical emergency

There are a few symptoms that are possible indications of a serious medical condition requiring surgery, and patients with these symptoms should seek medical attention immediately. These symptoms include:

• Sudden bowel and/or bladder incontinence (cauda equina syndrome)
• Progressive weakness in the legs (cauda equina syndrome)
• Severe, continuous abdominal and low back pain (see abdominal aortic aneurysm)

Muscle strain and low back pain

The majority of episodes of acute lower back pain are caused by a muscular strain (such as from lifting a heavy object, a sudden movement or a fall). Even though this doesn't sound like a serious injury, the low back pain can be very severe and last for several hours, several days or even a couple of weeks.

When the muscles in the back are strained or torn, the area around the muscles can become inflamed. With inflammation the muscles in the back can spasm and cause both severe lower back pain and difficulty moving.

Healing from acute low back pain
Fortunately, muscle strains usually heal with time (a couple of days or weeks) because muscles in the low back have a good blood supply to bring the necessary nutrients and proteins for healing to take place.

However, an episode of low back pain that lasts for more than two weeks can lead to muscle weakness (since using the muscles hurts, the tendency is to avoid using them). This process leads to disuse atrophy (muscle wasting), and subsequent weakening, which in turn causes more low back pain because the muscles are less able to help hold up the spine.

Exercise helps prevent acute low back pain
As a general rule, people who are active and well-conditioned are much less likely to suffer from low back pain due to muscle strain, as regular exercise stretches the muscles so they are less likely to strain, tear or spasm.

There are three types of muscles that support the spine:

• Extensors (back muscles and gluteal muscles)
• Flexors (abdominal muscles and iliopsoas muscles)
• Oblique's or Rotators (side muscles)

While some of these muscles are used in everyday life, most do not get adequate exercise from daily activities and tend to weaken with age unless they are specifically exercised. A complete exercise program for the low back should consist of a combination of stretching, strengthening, and aerobic conditioning.

Common conditions that cause lower back pain

For patients with low back pain that lasts longer than two weeks to three months, or with predominantly leg pain, a more specific and definable problem is often the source of pain. Several types of low back and leg pain tend to be more common in either younger or older adults.

Common types of low back pain for young adults (< 60 years old)

1. Leg pain and possible numbness
   Pain that radiates through the buttocks, as well as pain and possibly numbness that radiates down to the foot, is frequently caused by a disc herniation in the lumbar (lower) spine. This type of pain is usually worse after a long period of standing or sitting.

   • See also Lumbar disc herniation
   

2. Mechanical low back pain
   Low back pain in young adults that is caused by movement (such as bending forward, running) is commonly caused by a syndrome called degenerative disc disease. This condition can result from a twisting injury that weakens the disc. The low back pain symptoms of degenerative disc disease can become chronic and may tend to fluctuate and at times become significantly worse.


3. Low back pain (and possibly leg pain) that worsens when standing or walking
   Sometimes a vertebral body in the low back slips forward, causing stress on the disc, which in turn may cause low back pain and may sometimes cause leg pain. These painful symptoms are sometimes caused by a stress fracture that occurs at a young age.|

   • See also Isthmic spondylolisthesis

Common types of low back pain for older adults (>60 years old)

1. Low back pain that is worse in the morning and in the evening, and stiffness
   Low back pain that is most pronounced first thing in the morning and later in the day is often caused by facet joint osteoarthritis (degenerative arthritis), a condition that involves breakdown of the cartilage between the facet joints in the back. The pain and stiffness is a result of the lack of cartilage between the joints.
   
   • See also Facet joint osteoarthritis


2. Pain down the legs when walking and standing upright
   Leg pain that occurs when walking, and increases with more walking, can be caused by conditions such as lumbar spinal stenosis or degenerative spondylolisthesis. Both conditions place pressure on the nerves at the point where they exit the spine. Standing upright, such as in normal walking, increases pressure on the nerve and results in leg pain.

   • See also Lumbar spinal stenosis and Degenerative spondylolisthesis

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