Vocal cord nodules...
I was listening to a YouTube documentary about Led Zeppelin singer Robert Plant yesterday. In the video, they mentioned him having surgery to remove vocal cord nodules and that the news wasn't widely publicized.Common to many singers who have had this type of surgery, it often changes your voice. Some singers recovered and some have had to change their style as their singing voice was totally affected by the surgery.
It was noted by true fans somewhere around 1972-1973 Plant cut back on his high-octave wailing and screams in live concerts, possibly as a result of the surgery.
I Googled and found a long list of professional singers who had vocal cord issues including cancer, polyps and burst blood vessels. For example, Rod Stewart's throat cancer surgery set his recovery back more than nine months.
I'm unable to find any stories on Sting having vocal cord surgery. A decade ago he was doing acoustic versions of Roxanne and 'eased up' on the high notes but in this 2017 performance he's done a great job of holding it together.