When you cut yourself, the two parts of the cut heal by sticking together with a collagen and fibrin mesh which the blood clot sits in and forms a scab. If it's a significant wound, it eventually forms a scar.
Inside your body, similar healing processes can take place, and where there have been divisions of tissue, either by blunt dissection (e.g. the surgeon just pushing the tissue layers apart to get to the deeper tissue) or by cutting or slicing, when the body heals, it doesn't always heal in the same way as it started out.
Sometimes, organs stick to each other, and it all gets a bit messy, or a bit of scar tissue forms in a band across part of a body cavity. It can cause no trouble for a long time, but then, say, a piece of bowel gets looped into that band and gets caught, or gets twisted, and it can suddenly become a medical emergency. But there is no way of telling that it was even there until it is a problem, so it isn't something to worry about.