Most Common Causes of Lumbar Back Pain

Recurrent Herniated (ruptured) Disk

The disk is composed of two parts; the soft center (nucleus pulposus) and the surrounding tough, fibrous outer ring (annulus). A herniated disk is one in which the tough outer ring tears (annular tears ) and allows the soft center to protrude or bulge.  Bulging is an early sign of wear and tear of the disk. A ruptured disk is when the nucleus pulposus pushes through an annular tear. Even a small amount of disk material in a small spinal canal can cause significant symptoms by pressing on the nearby spinal nerve causing weakness, numbness, and pain all along the nerve. The amount of pain can range from mild to severe and be made worse by walking, bending, lifting, sneezing, coughing, and straining.

The two most common levels of disk herniation are are at L4-L5 and L5-S1.

Spondylolysis

Spondylolysis is a fracture or defect of the vertebrae and is found most often at the fifth lumbar vertebra.  This defect is thought to be due to a stress fracture. For people with frequent and significant episodes of disability related to spondylolysis, surgery to fuse the fracture may be recommended.  The defect is common in female gymnasts, power weight lifters, and football linemen.

Instability

As part of the aging process, the intervertebral disks lose some of their water content. They become stiff and flatten, losing their ability to act as shock absorbers. The vertebrae become unstable and slip back and forth irritating the nearby nerves. Instability can also result from bone tumors or infection of the vertebrae.

Spinal Stenosis

Spinal stenosis is a narrowing of the spinal canal or of the nerve root openings. The narrowing may result from bone spur formation, soft tissue encroachment, or both. This narrowing may put pressure on the nerves or spinal cord, causing back and leg pain. In addition to surgical removal of structures that are causing the pressure, spinal fusion helps relieve pain.

Spondylolisthesis

Forward slip of one vertebra on top of another

Spondylolisthesis is a forward slip of one vertebra on top of another (which can occur at any level) resulting in a pinched nerve. Spondylolisthesis is classified as developed or acquired. Developed happens over time from an abnormal architecture of the spine. Acquired spondylolisthesis occurs after a significant injury and is graded I through IV. Spondyloptosis is a vertebra that has completely slipped over the edge of the lower vertebra. There are several causes for the slip. Some slips are due to simple wear and tear of the bone, others are due to injury. Sometimes a hairline fracture allows vertebrae to slip forward on top of each other. Still others are thought to be related to inherited bone variations. The more significant the slip the more likely the fusion will all require instrumentation.


Other reasons for spinal fusion include treatment of a fractured (broken) vertebra or correction of a deformity.