Hello I have gone through your complaint. As your child had spina bifida
previously, there may be some associated urinary problems. The abscess
which had occurred previously is in high risk zone. The previous uti might have been completely cured but as it is at high risk infective zone, the urine itself will act as a media for the growth of organisms. According to your doctor decision you need to get operated and a further delay may cause few more complications.
Thank you. Good day