Patent urachus: A surgery to repair a bladder defect. In an open (patent) urachus, there is an opening between the bladder and the umbilicus. The opening usually closes before birth. An open urachus typically occurs in infants.
Failure for the lumen of the urachus to be filled in leaves a patent (open) urachus. The telltale sign is leakage of urine through the umbilicus. A patent urachus needs to be surgically removed.