In 2004 I had compications from lumbar spinal fusion surgery that left me with paralysis form the knee down on the left side. The leg (from the knee down ) is very cold to the touch. My wife stated it felt like it just came out of the freezer ! My neurologist suggest it has to do with the loss of muscle response and nerve problems that effect the ability of the viens and caplaries to respond and not a circulation issue ? Should I be concerned and pursue other medical options ?
I agree with your doctor, paralysis with time cause lower circulation due to disuse, you should only be concerned if your foot has a weird smell or red line or black color Good Luck