TENS = Transcutaneous Electrical Nerve Stimulator
IMO, one of the BEST ones made is the 'AUVON' brand and you can purchase it at Amazon:
https://www.amazon.com/s?k=AUVON&ref=nb_sb_noss_2
You place the stimulator pads in the area that is the source of the pain. You can adjust the level of the electrical impulses. I set mine on the highest setting, usually. Doesn't ALWAYS work for me but most of the time it definitely interferes with my pain and reduces it significantly.
Prayers for your wife. Please consider buying one of these devices to help, it's not very expensive!
ping