Trucker, I have tried so many things over the years,, I’m sure anyone here that dealt with this problem as recently as the 80’s remember that the only protection you could trust was cloth diapers & plastic pants! The few disposables out there were truly just accidents waiting to happen if you leaked more than a teaspoon...
The reason I tell you this is that Kins/Babykins has a pair of waterproof pants that are a real game changer when it comes to comfort & reliability. At first I was a bit hesitant because they call them Taffeta, and that sounded more like my Wife’s lingerie than anything! I’ve known these folks at Kins for quite some time so I gave them a call and they sent me a pair to try. They wanted to differentiate these from the heavy rubberized polyester pants out there because they are considerably different! They are lighter than a pair of boxers, they breath so it cuts down the heat and they’re so comfortable you can forget your even wearing them. I too get the gap at the top/back of my thighs from many of the better disposables, and these keep things close to your body to prevent a leak in the first place.
When I had my most recent neck/spine rebuild surgery I was wearing a pair over a Northshore Megamax, when I woke up in recovery 7 hours later everything was still in place. I requested no catheter if not absolutely necessary. I had a number of Drs & Nurses ask me where I got them after seeing how well they worked. Apparently they see a lot of this as this team specializes in complex spinal cord injuries, tumors etc. To them it was more like talking boxers or briefs than adult diapers as they are often the ones breaking the news to us that incontinence is now part of your life.
I hope they’ll work as well for you!