Moderate numbness in toes of both feet for the last year. Feet have grown a size in the last year - I'm 58 years old. Been tested for everything (MRI, blood work, nerve conduction, scar tissue from back (L4-L5 discectomy) surgery 20 years ago, blood sugar, B-12 deficiency, MS, lupus, ALS, PSA count, etc.) No definitive diagnosis. Take Viagra once a week for last 6 months - could that be a contributor? Also, ride horses, run, lift weights.