I have had two major (that's what the doc said) surgeries to correct significant lumbar stenosis and other deteriorations in that area. The chronic severe pain and the distinct probability of the loosing the ability to walk and balance left me little choice other than surgery since no other modality could provide the physical alterations needed. My experience has taught me that the pain and other discomforts of these difficulties can manifest in many seemingly unrelated areas from the spine and below. At the present I am about 6 months out from my last surgery and I still require narcotics. At times I am not sure if this severe discomfort is from the healing (can take about a year), the issue not being quite solved yet, or the original or even a new deterioration (and believe me I check with my surgeon). What I am getting at is this; Your 13 spinal surgeries opens a whole host of pain causing possibilities. Maybe you have considered that walking triggers and increases the feet "burning" indicating that something in your spinal column is the cause and being compromised to the point of the symptoms you describe can perhaps lead to further difficulties. Anyways with just my two surgeries some of my own procedure questions were not easily answered, so with 13 surgeries I hope you have a really good team. Hope everything works out well for you.