New development and progression of renal scarring in children with primary VUR.

To study the development of new scars and progression of previous scarring, we analysed 711 children with primary VUR. New scar or progression of previous scarring was observed in 7.3% of the kidneys with reflux. Factors which promote the formation of new scars are high-grade VUR, recurrent UTIs and high-pressure bladder which results in high-pressure reflux. The average age of new scarring was from 7 to 9 years. We emphasize the importance of the follow-up study until the age of 15 years, even after reflux has stopped following surgery.