Q: I am a 33 year old man. I am experiencing pain in my lower back and severe pain on my left buttocks and leg. I feel like I have a cramp on my left leg all the time. I took prescribed medication for this but had no relief. I recently had an MRI done. The following are the results: Large left paracentral disk protrusion at L5-S1 causing posterior displacement of the left S1 nerve root; Mild annular bulge at L4-L5. My doctor referred me to a neurosurgeon but has not explained what is wrong with me. The neurosurgeon has not given me an appointment yet. Can you please explain these medical terms?

A:Yours description is very typical of a patient with disc prolapse pinching on a nerve that supplies your leg muscles. Let me explain. Our spine is made up of 33 blocks of bone called vertebrae. You might remember this from your high school biology. Between each pair of these blocks there is a shock absorber that essentially allows movement between the blocks and also functions as a shock absorber. There is a canal within the vertebrae which contains the main nerve centre between the body and the brain. This is the spinal cord. Nerves pass from this spinal cord in pairs between each pair of vertebrae. In some patients this shock absorber breaks through the disc to come out into the canal. There it pinches nerves passing close by. Depending on the site of the nerve pinched the patient has pain radiating down the legs. Your MRI report tells the exact level where the nerve is being pinched. In your case the main pinching is that the vertebrae between the 5th lumbar and 1st sacral vertebrae. This is a mechanical problem so if there is a significant pinching your symptoms will be severe. In such cases pain killers may not help to give complete relief. The offending disc has to be removed surgically. Normally people are scared of getting this done because of the fear of paralysis. However, with modern day techniques the surgery is reasonably safe and often the patient is up and about within a day or two. In some hospitals the neurosurgeons do such cases where as in others the orthopaedic surgeons operate. As long as the surgeon is experienced it should not matter. I hope I have been able to explain to you sufficiently. Do let me know if you need any clarification.