Department of Anaesthesia, Royal Free Hospital, London, UK
The intervertebral disc can cause pain because of intrinsic degenerative process or compression producing radicular symptoms. It is responsible for 40 % of low back pain.
Disc degenerates with ageing. Various processes seen are dehydration, fissuring, new vessel formation and bony changes. Dehydration leads to fissuring and release of pro-inflammatory cytokines (TNFα, IL-8, IL-6) leading to inflammatory process. New vessels are formed within the annulus along with the spread of nerves which get sensitised with the inflammatory process and contribute to the pain. Loss of disc height may also contribute to pain by altering the mechanics of the spine. Cigarette smoking is a risk factor.
46.2 Clinical Features
It may present as back pain or back pain with radicular pain/radiculopathy. Mostly, it is gradual in onset and may be referred to the lower extremity in a non-dermatomal pattern. More than one spinal nerve may be involved. Pain usually gets worse with weight lifting, standing or sitting and is relieved by lying down. Bending forward is painful.
MRI (most sensitive and specific): shows disc dehydration, modic changes and disc herniation. T2-weighted images show high-intensity zones which represent the disc material in annular tear or oedema fluid within the annulus.