I'm A 56 Year Old Committed Distance Runner (50-55 Miles

I'm a 56 year old committed distance runner (50-55 miles a week) suffering form 15 month bout of plantar faschiitis. Second time around with first about three years ago. It's really bad according to MRI and orthopedic consultation. Located at base (rear) of my heel. Weighing options of surgery, platelet replacement, and shockwave therapy. Not sure my orthopedic realizes the degree to which I run (college XC, shoe company sponsored kind of runner back in the day...) Thoughts?