At the most basic level, all back pain is caused by damage to the nervous system. The nerves simply produce pain in response to a harmful event (thereby alerting the brain to the problem). The pain is detected by special receptors in the body, and then transmitted, usually via the spinal cord, to the brain.
At a structural level, back pain is caused by a number of different conditions. Some of the more common problems are listed below:
- Bulging disc;
- Herniated disc;
- Direct, nerve-root impingement;
- Spinal stenosis;
All of these conditions lead to nerve-root impingement either directly or indirectly. For example, if the pressure on one of the intervertebral discs becomes too great it will, in all likelihood, start to bulge (by a fraction of a millimetre). This leads to pressure on the surrounding nerve fibres, resulting in pain.
The surgical approach to ‘solving’ these conditions is, quite frankly, brutal. For example, in cases where the intervertebral disc is either bulging, or herniated, the surgeon will remove some, or all, of the disc to lower the pressure on the nerve fibres, a procedure known as a Discectomy (disc-ectomy, pronounced disektomy).
But, in the absence of a disc, the spine will not function properly; it becomes unstable. To combat this, the surgeon performs a spinal Fusion, literally welding the two vertebrae (which previously surrounded the disc) together.
Other, common, forms of spinal surgery include IDET (Intradiscal Electrothermal Therapy) and Laminectomy.
IDET is used to treat small herniations by inserting a wire into the wall of the disc and then heating it to 90°C. This causes the wall (the annulus fibrosis) to thicken and contract, promoting closure. The heat also burns the small nerve endings within the disc wall, making them less sensitive.
A laminectomy is similar to a discectomy but instead of removing the intervertebral disc, part of the vertebra itself is removed (again, in an attempt to decrease the pressure on the surrounding nerve fibres). The part that is removed is called the lamina, hence the term laminectomy.