My chiro has that kind of table, but I don't have herniation's or spinal stenosis, so I guess I can't help you with info about that part of it.

Mine does use Low Level Laser Therapy {LLLT}, IF stim and triggerpoint/pressure techniques along with adjustments.
I wonder if the LLLT {also called cold laser} or even the IF stim might be helpful for you.
There is also IR {infrared light} but it does not go as deeply into the tissues as LLLT.
There are various kinds of electrical stimulation also- specific for nerves, muscles etc.