HERNIATED DISKS

A spinal disc herniation, incorrectly called a "slipped disc", is a medical condition affecting the spine, in which a tear in the outer, fibrous ring (annulus fibrosus) of an intervertebral disc allows the soft, central portion (nucleus pulposus) to bulge out. This tear in the disc ring may result in the release of inflammatory chemical mediators which may directly cause severe pain, even in the absence of nerve root compression. This is the rationale for the use of anti-inflammatory treatments for pain associated with disc herniation, protrusion, bulge, or disc tear.

It is normally a further development of a previously existing disc protrusion, a condition in which the outermost layers of the annulus fibrosus are still intact, but can bulge when the disc is under pressure.

Surgery is indicated if a patient has a significant neurological deficit, or if they fail non-surgical therapy. The presence of cauda equina syndrome (in which there is incontinence, weakness and genital numbness) is considered a medical emergency requiring immediate attention and possibly surgical decompression. A primary focus of surgery is to remove “pressure” or reduce mechanical compression on a neural element: either the spinal cord, or a nerve root.

Discal herniations can occur from general wear and tear, such as jobs that require constant sitting, but especially jobs that require lifting. Traumatic (quick) injury to lumbar discs commonly occurs from lifting while bent at the waist, rather than lifting while using the legs. Minor back pain is an indicator of general wear and tear that may result in a traumatic event from bending to pick up a pencil from the floor. When the spine is straight, such as standing or lying down, internal pressure is equalized on all parts of the discs. While sitting or bending to lift, internal pressure on the disc can move from 17 psi (lying down) to over 300 psi (lifting with a rounded back).

The common "slipped disc" (contents of the disc move or slip into the spinal nerve canal) occurs when the disc membrane covering (the annulus fibrosis) is compressed on the front (stomach side) while sitting or bending, and extruded (stretched) thinly on the rear (back side).