I haven't, but will look into it. Back issues are from a work injury as a young man, boss begged to stay on site so no injury time would be allotted to the bay, brought me an ice pack... after 30 minutes my back felt great...until I realized I had a 6"X 8" section just above the pelvis that was frozen solid.. he packed the ice pack with dry ice... my lower 3 vertebra are virtually fused now. They pull us in as youngsters, abuse us till we're almost ready to fall apart, then put us,out to pasture, without a second thought. The Green goddess keeps me away from having to participate in the big pharma screw job.