Here is the cut and paste...
Based on the results of animal studies in our laboratory, it appears that the mechanism of shock waves first stimulates the early expression of angiogenesis-related growth factors including eNOS (endothelial nitric oxide synthase), VEGF (vessel endothelial growth factor) and PCNA (proliferating cell nuclear antigen), then induces the ingrowth of neovascularization that improves blood supply and increases cell proliferation and eventual tissue regeneration to repair tendon or bone tissues.
Makes a lot of sense, like a deep-tissue massage.
There is something in this. Have a read, acoustic waves ease spasticity/pain.
I'll hunt around and find more. These machines retail at $1000~ish.
I'll check if my hospital offers it, but I doubt it.