I have come to belieive that insurance companies have it in their corporate charters the golden rule of "avoid paying any and all claims.
With that said, and off my chest, I would suggest going to the manufacture's web site http://www.intuitivesurgical.com/index.aspx and arm youself with as many facts as possible. Go to the "patient services" tab, it has lots of information. You might even consider contacting Intutitive Surgical's customer services department (888-409-4774 ext.1 ) and explain your situation - maybe they would advocate for you with your insurance company.
I had the Davinci procedure 15 months ago with GREAT results!