Just noticed your post of 23 March 2012.
I was also trying to ascertain my surgeon's track record with mvd surgeries after the 1st consultation. I was given a rather vague reply and felt that had I persisted with questioning, I may sound rude. So I tried to get this information from 3rd party to no avail. Then at my pre-surgery assessment, the doctor told me that I can contact the surgeon's secretary to ask for the success rate based on past patients' records. I did not bother to do so by then as it was just a week before the scheduled surgery. If you are really curious, perhaps it is worth giving it a try by asking his medical secretary.
All the best and hope you have a successful surgery.