I had a nerve stimulator implanted on a trial basis two years ago. Nobody knows the frequency until you try it and see what works for you. Please ask lots of questions and get more information before you do anything. Ask if they do a trial implant to see if it will indeed work for you before committing to a permanent one.
After trying this I discovered it didn’t work well enough for me and doctor advised against the permanent implant.
Best of luck to you. Wishing for good results.