
I just had major abdominal surgery a month ago, and I'd suggest you look at underwear for post surgery, you'd be amazed at how sensitive your incision site can be, and how much discomfort knicker elastic can cause.
If you want a cheap solution, have a look at Tescos microfibre shorts style pants, which are £5 for two pairs, the band on them sits on my navel line ( I don't have one any more !) and well above my wound.
If you want the ultimate in comfort however,look at the Comfizz website, they have all manner of stuff for surgical wounds, and are extremely well made and comfortable, but you will pay £10 a pair.
The good thing about them is some of the range will also help to prevent a hernia, which you'll be more prone to along the incision, and believe me, there's no better feeling than something gently holding it all in, in the days post op.
They also do " belly bands " which are good as you'd only need one really, do the same job as the knickers, and if you tucked it inside your current knicks, should keep your wound comfy.
You might have bother with wearing trousers too, depending on the waistline, so take in high waisted leggings or jogging bottoms to the hospital.
Hope this is helpful, good luck :)