I am currently in a trial right now with my Dr and the NEVRO HF10 Spinal Cored Stimulator. The leads are placed under the skin and up my spine from my surgical sight L4-L5 to L5-S1 (bilateral 2 level fusion in 2003). The controller is exterior as is wires to the controller. The majority of my back is taped to make sure nothing comes loose. I was also given extension wires when I sleep, so I do not have to keep the controller around my waist (the controller is on Velcro long enough to wrap around your waist.) It takes about 48 hours for the system to start working, and you are not allowed to take a shower (sponge bath only) until the trial is over.