Spinal canal stenosis
Spinal stenosis is narrowing of the canal through which the spinal cord and the nerves pass. The narrowing alone may not cause any pain or problems. When the narrowing becomes severe, it starts to compress the spinal cord and the nerves. This will cause arm pain (brachalgia) or leg pain (sciatica) or other neurological signs. Narrowing can be from a disc prolapse, but in the elderly it is due to wear and tear. Arthritis in the facets joints can cause swelling which can narrow the spinal canal.
As we described earlier, the spinal cord is like the Motorway and the nerves are the “A” roads from the motorway. When the compression affects the spinal cord (motorway) it causes Myelopathy. The patient suffers from imbalance and pins and needles in both hands. Fine motor activity like counting coins, knitting or turning the key become difficult. There may also be difficulty with passing urine or there may be incontinence.
Radiculopathy is when the compression affects the nerves (the A-roads). Rather than the spinal cord. The patient usually only suffers from pain and numbness in one limb.
Worn out discs and weak ligaments and muscles cause this. This allows one vertebra to slide forward over the other. As the neural arch (the ring in each bone) slide apart, it can pinch the nerves coming through them. This usually occurs one above the last disc at L4/5.
Patients with spinal canal stenosis may not experience pain at rest. They may only experience pain when they walk. After they walk a certain distance, they would have to sit down or lean forward to take a short rest. Claudication is the term given to Pain / cramp in the legs after walking. These patients may not have any difficulty cycling which may be a good way to exercise in stenosis.