Think of this parallel – it’s the same idea as stitching up an open cut. Let’s say that you have a large cut on your arm. If the cut remains spread apart, your body will have difficulty healing itself. So here comes the doc…. he’ll bring the two edges very close to eachother and then apply stitches. The purpose of the stitches is to keep the two edges butting up next to eachother for long enough that the cells can regenerate and the wound will close itself. The stitches didn’t heal the wound, but they assisted in allowing the body to heal itself.