Lumbar disc herniation and degenerative disc disease

Disc herniation, commonly know as "slipped disc" and degenerative disc disease are relatively commonly found on images such as X-rays, C.T. scan, ultra-sound or MRI, even in many people without lower back pain. So it is often coincidental that a herniation is found in the same location as lower back pain.

The inner third of your spinal discs consists of a gel-like material and the outer two thirds consists of many layers of tough fibrous sheets. Failure to fully contain the inner gel by a weakening of the outer wall results in a herniated disc, where the disc contour balloons outwards from its normal position by various degrees. These variations are known as herniated, bulging, prolapsed, ruptured, protruded, or extruded discs. They may compress or ‘pinch’ nerves exiting the spinal canal.

Many people believe that once your spinal discs have ‘slipped’ then they remain for the rest of their days, but studies show this is not the case. Various studies of spinal disc changes over time have reported spontaneous reduction of herniation in 35% to 100% of cases, depending on the differences in subjects studied and the measures used in the study. This means that given time and “normal” loading such as exercise the vast majority of “slipped” discs regress by themselves.

In one such study, 154 subjects with an average age of 45 years complaining of pain shooting into their legs completed an 8-week exercise program. They had an MRI taken before and 14 months later. The study found only 3% of bulges and 38% of focal protrusions* regressed, whereas 75% to 100% of broad-based protrusions, extrusions**, and sequestrations*** (the largest kinds of herniation) regressed. The study also found that nerve root compression regressed in 21% to 80% of subjects depending on the disc contour.

*Disc protrusions are similar to bulging discs, but the protruding part is categorised as focal or broad-based. “Focal” means that less than 90 degrees of the disc circumference is protruding outside of the normal boundaries. “Broad-based” means that 90-180 degrees of its circumference is protruding.

**Disc extrusion is a condition where the inner gel core ruptures through the outer disc wall.

***Disc sequestration is the most severe degree of disc herniation, in which the inner gel core of the disc spills out and completely separates from the disc.