Back pain and osteoarthritis

Herniation

Intervertebral disks are a critical component of the load-bearing structures of the spinal column. They consist of a gelatinous center (the nucleus pulposus), which is encircled by a strong collar of fibrocartilage (the annulus fibrosus).2 The disk absorbs shock, changes shape, and allows movement. The nucleus pulposus can be squeezed out of place and herniate through the annulus fibrosus, a condition referred to as a herniated, ruptured, or slipped disk. The intervertebral disk can dysfunction due to trauma, aging, or degenerative disorders of the spine. Trauma can result from activities such as lifting while in the flexed position or simply suppressing a sneeze. With age, the gelatinous center of the disk dries and loses elasticity, causing it to fray and tear. Most lumbar herniations occur at L4 or L5 to S1. Most cervical herniations occur at C6 to C7 and C5 to C6.

clinical manifestations of herniated disc

A herniated disc with accompanying pain may occur in any portion of the spine: cervical, thoracic (rare), or lumbar. The clinical manifestations depend on the location, the rate of development (acute or chronic), and the effect on the surrounding structures. Functional limitations are the main manifestation reported by patients. Intensity in patients with low back pain has a direct effect on ADLs and sleep quality. The nerve roots of L4, L5, S1, S2, and S3 give rise to back pain that spreads down the back of the leg and over the sole of the foot.

Disc degeneration

Disc degeneration pushes the capsule back into the spinal canal. It could also rupture and allow the nucleus pulposus to be pushed back against the dural sac or against a spinal nerve as it emerges from the spinal column. This disease of the spinal root produces pain and extreme sensitivity to touch due to radiculopathy (pressure in the area of distribution of the involved nerve endings). Continued pressure may produce degenerative changes in the involved nerve, such as changes in sensation and deep tendon reflexes. Disc degeneration is a common cause of back pain. The lower lumbar discs, L4-5 and L5-S1, are subject to the greatest mechanical stress and the greatest degenerative changes.

Diagnosing lumbar disc disorders

The MRI scan has become the diagnostic tool of choice for localizing even small disc protrusions, particularly for lumbar spine disease. If the clinical symptoms are not consistent with the pathology seen on MRI, CT scanning and myelography are performed. The straight-leg test is done in the supine position and is performed by passively raising the person's leg or by extending the knee while the person sits with both hip and knee flexed at 90 degrees. The test is positive if pain is produced when the leg is raised to 60 degrees or less.

What is a intervertebral disc?

The intervertebral disc is a cartilaginous plate that forms a cushion between the vertebral bodies (see Fig. 65-6A). This tough, fibrous material is incorporated in a capsule. A ball-like cushion in the center of the disc is called the nucleus pulposus.