Disc protrusions may occur anywhere along the spine but the most common regions are the cervical spine (neck) and lumbar spine (lower back). Many people have disc protrusions or bulges but may be unaware of that they have these changes. Some however are symptomatic causing pain, numbness, pins and needles (paraesthesia) or weakness of an arm or leg.
There are several lay terms that are used interchangeably and this can be confusing. A disc bulge usually means that the disc is intact but the outer layers of the disc are ‘bulging’ or pushed outwards. In the right spot this may cause symptoms but in absence of symptoms would usually need to specific treatment. A disc protrusion is where a piece of the inner part of the disc has pushed through the outer wall. This is more serious and likely to cause symptoms. A disc extrusion is where the inner part of the disc actually pushes through and may detach from the outer part of the disc.
Whether is causes symptoms and what symptoms a disc causes depends on the position in which the protrusion (or extrusion) occurs. In the central (middle) part of the spinal canal there is more room. It is therefore less likely to cause upper or lower limb pain but if the it is large enough may press on the spinal cord or caudaequina (the lower lumbar nerve roots) causing paralysis and or bladder and bowel symptoms. Most commonly however the disc is in the posterolateral or lateral position where it tends to ‘pinch the a nerve’ causing pain and/or numbness and weakness. This is called a radiculopathy.
Management depends on the severity of symptoms and most patients will be treated conservatively unless there is weakness or paralysis in which case surgery is often considered much sooner. Most patients that have a radiculopathy do not require surgery and will respond to conservative management in the form of rest, analgesia and physiotherapy. However some cases may also benefit from a cortisone injection under CT or X-ray guidance.
Surgery is usually reserved for those who fail conservative management and who have MRI or CT images that are consistent with the clinical symptoms. As mentioned those with weakness, paralysis or spinal cord compression will usually proceed to surgery much more quickly.
For specific information in relation to treatment please see the patient information pages for ACDF or lumbar microdiscectomy.