Hope you're keeping well - haven't seen you on here for a while...
Yes i did know about this and i think that the sac surgery which the astronaut had was very successful. It makes me wonder at times why this op works for some and not for others, maybe its down to the surgeon and how good he is at his job? Most people here on the forum including myself who has had the sac op, have been unsuccessful and their symptoms either returned within a week or two after the op or if 'lucky' like i was (LOL!) came back within 9 months! I don't think that the risks involved are worth the gamble, if one is basing this op on past stats - reason it fails though is the big question, think there is a theory that the valve or incision made within the sac gets blocked with crystals but who knows mate?