Hello, I am in a similar situation. However, in addition to two parathyroidectomies, I have a paralyzed laryngeal nerve from the last surgery. I have spoken to Norman Parathyroid Center, and they said a third surgery is not out of the question. There are other high volume clinic in the US, too. One is at the University of Wisconsin. A surgeon there, according to someone who went to her serves mostly patients who are difficult to operate on due to internal scar tissue, etc. And, I think there is a clinic in Arizona run by a woman who used to be a surgeon at Norman. From what I am learning the higher the volume of surgeries performed by a surgeon the better.

I asked my Endo about radio frequency ablation, which I think may be the same thing you are referring to. She was not enthusiastic and in fact said it wasn't used for hyperparathyroidism, but AI says it can be. And this is what google AI says: "Reduced risks compared to repeat surgery: Repeat parathyroid surgery carries an increased risk of complications such as recurrent laryngeal nerve injury and hypoparathyroidism due to scar tissue formation. RFA, with techniques like hydrodissection to protect surrounding structures, may potentially lower these risks." However, rarely, RFA can also damage laryngeal nerves. I have not given up on that solution.

Just FYI there are two facebook groups that discuss hyperparathyroidism. The folks in the groups mostly have had surgery or will soon. You might ask there about radiofrequency ablation, in fact I hadn't thought of doing that before this (I had just asked about surgery), but I think i will ask today. Good luck to you. I hope all works out for the best.