Low back pain is a common, painful condition affecting the lower part of the spine. It can result from injuries to the muscle, ligaments, disc, joints or nerves. It is second only to respiratory infections as a cause to visit the doctors office. Low back pain will affect the majority of the population in their lifetime. As we age almost everyone has some arthritis and degenerative disc disease in the lumbar spine.

Patients will complain of pain in the lower back. Often it is difficult to flex, extend, or rotate the spine. Occasionally patients will have pain, numbness, or tingling in the legs. This can occur with overuse such as repetitive lifting, lifting too heavy in an awkward position, and prolonged sitting or sleeping in an awkward position. There are certain red flags that physicians and patients should be aware of and may need more emergent treatment. These include history of IV drug use which could result in an infection, a history of cancer which could metastasize to the spine, a history of trauma which could result in a fracture, or bowel and bladder changes.

The lumbar vertebral bodies compose the anterior of the spine. The intervertebral discs are between each lumbar body and cushion the spine. In the middle of the spine is the spinal canal. The spinal canal is filled with the spinal cord at the top of the lumbar spine and becomes a group of nerves at the bottom of the lumbar spine called the “ cauda equina”. Behind the spinal canal the facet joints connect the lumbar bodies. The ligaments surround and stabilize the spine and the muscles attach and move the spine. All the nerves that supply the legs leave the spinal cord through tunnels called the foramen.

The most common reason for low back pain is a muscle strain. There are multiple degenerative disorders that can cause low back pain as well. A disc bulge or disc rupture can cause lumbar pain. This can occur acutely or an asymptomatic disc bulge or rupture can become aggravated. A large disc bulge or rupture can irritate the nerves going into the legs and result in pain, numbness, and tingling. This is called Sciatica or Lumbar Radiculopathy. Lumbar stenosis occurs when the spinal nerves are aggravated due to narrowing of the spinal canal or foramen. This occurs due to bulging of the degenerative discs and enlargement of the facet joints due to arthritis.

Obesity and smoking are major risk factors for lumbar injuries. Smoking decreases blood supply to the discs which worsens disc degeneration and makes them more prone to injury. Obesity puts extra weight on the spine and the system ultimately fails under pressure. Lack of core (abdominal and back) strength and core flexibility makes people prone to back injuries. Poor lifting mechanics will lead to back injuries as will prolonged sitting. It is often said that sitting is the new smoking. Sitting all day in a flexed position will ultimately weaken the spine. Finally stress such as job dissatisfaction can result in back pain and can make recovery difficult.

The physician will check the spinal alignment, evaluate motion and palpate areas of tenderness. Certain maneuvers stretch the sciatic nerve and will check for nerve irritation. Loss of sensation, strength, or changes in reflexes is a sign of nerve irritation or nerve injury.

X-rays are usually the first test ordered. They will show most fractures. They can show many tumors. Although the X-ray will not show the disc it will show all the signs of degenerative discs such as narrowing of the disc space and bone spurs. It will show arthritis in the facet joints as well. By middle age almost everyone has some disc space narrowing and facet arthritis in the lower lumbar spine.

MRI is not usually indicated unless conservative treatment fails. If there are concerns from the History, Physical Exam, or X-ray an MRI may be ordered sooner. An MRI is not needed to start medicines or therapy. It is usually required before considering injections or surgery.