The pathological changes associated with LCS from any cause have been constriction of the nerve roots and the dura and then become adherent due to arachnoid changes, degeneration and demyelination with regeneration of nerve tissue, absent arterioles at the site of constriction, collapse of venules and formation of A-V shunts at the proximal end. Synovial cysts may form and compress the nerve roots and become adherent to the dura.
The symptoms of LCS arise from a combination of mechanical and ischemic metabolic factors.
The events progress as follows:
mechanical contriction of the neural lesions----> impairment of free flow of CSF and consequent adhesions----->venous obstruction and A-V shunts----->ischemia and metabolic end-products act together------>large sensory fibres more susceptible than smaller motor fibres------>ectopic nerve impulses are fired------> variety of paraesthesiae------> long-term compression causes fibrosis and adhesions----> neurological weakness occurs.
The symtoms are more common in the elderly since with ageing the nerves are more susceptible to compression.
Watch the animated video of spinal stenosis HERE
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