"...if one has back surgery a zipper should be installed..."

Yup. Had lower back surgery in 1983, again in '87 to remove scar tissue from the first surgery that had caused some non-repairable nerve damage to my left leg/foot. Luckily I have been able to avoid another procedure (so far) with a combo of caution, motrin, flexril, neuronton, and vodka or rum. Only resort to the knife when you are living flat on your back 24/7, not eating or drinking 'cuz you are afraid to have to get up and go to the bathroom...