...the perfect time for you to clean while he's gone.

It's not easy to keep them from jumping after a surgery, but it sounds like you are on it.

The cardboard is a good idea. It works, then can be recycled.

My prayers are for him to have an easy surgery which takes care of the problem once and for all, a speedy and complete recovery, and for you to have an easy time with keeping him quiet for as long as needed.

Please let us know how it goes!