Many people get understandably concerned when they hurt their backs that they have damaged an intervertebral disc (the cushion which sits between each vertebra in the spine). Such damage can be referred to as a disc “bulge”, “prolapse” or “protrusion”, or a “slipped disc”- all these terms indicate the same problem. The intervertebral disc is the shock absorber of the spine and is made up of a thick, fibrous outer layer and a gel-like central portion. A prolapse occurs when the inner gel extrudes through the outer layer into the area around the nerve traveling to the leg. Disc prolapses usually occur at fairly predictable levels of the back i.e. the ones under the most strain or load.
In Western society we tend to lock our knees and hips and bend forwards from our backs, whereas in Eastern and ‘developing’ societies (where there is less reliance on chairs for sitting and more reliance on squatting), bending occurs through the hips. The hip joint is a ball and socket joint, designed for a large range of motion and is supported by big bulky muscles and ligaments. In contrast, the back is long and slender with relatively limited directions of movement and comparatively little muscle and ligament support. In analysing the anatomy, it is clear that bending and lifting should be performed by the hips rather than the back.
The lower back is therefore absorbing excessive loads when we bend incorrectly and over a period of time this will tend to weaken the outer fibrous layer of the disc, allowing the centre to bulge through. Prevention and cure for this problem involves retraining correct movement to increase knee and hip joint loading and decrease back loading.
The primary reason why back surgery fails (i.e. the patient gets return of symptoms) is that, whilst the surgery itself is successful, the patient has usually not been instructed to alter their habits of movements which initially caused the problem…… just like after many open-heart surgeries, patients are educated regarding lifestyle changes to address diet and exercise, so that the problem doesn’t recur! In this case, the patient needs to learn how to move correctly, to avoid loading the back and to make better use of the hips and knees.