Pulled through flesh
A stitch pierces through flesh on each side of an incision
If the flesh is fragile, if the flesh is only a small amount, or if there is tension on the flesh, the stitch can pull through the flesh. If the stitch is new, a patient can call the surgeon right away, to see if something else can be done to close the opened spot today. If the stitch is older, the doctor might let the wound heal "as is".