A bladder diverticulum is an “outpouching” of the bladder lining through the outer muscle layer. It is similar in concept to a hernia. These are most commonly seen in children at the site where the ureter (the tube that transports urine from the kidney down to the bladder) enters the bladder. Some children have a weakness of the muscle in the area where the ureter enters the bladder. As the bladder fills and especially as voiding (peeing) occurs, the lining of the bladder in this area may herniate out temporarily until the bladder is emptied. This will occur each time the bladder fills and empties. A diverticulum itself is rarely a problem that requires surgery. However, they are usually seen in children who have vesicoureteral reflux (VUR) on the same side. If a child has both VUR and a diverticulum on the same side, the VUR is less likely to resolve. Additionally, the presence of a diverticulum makes the minimally invasive treatment option for VUR less effective. We have extensive experience with bladder diverticuli and can explain the issues involved and help determine the best treatment for your child.