Definition: Aponeurosis or vesicoureteral reflux is a condition in which urine flows backward into the bladder when urinary tract symptoms like pain, fever, and chills persist for more than four to six days after an upper urinary infection (UFI) has been treated with antibiotics. This symptom usually starts between 7 and 10 days post-treatment. The other key feature of aponeurosis is that it also affects the urethra, leading to problems in urination, leakage, and pain from the testicles or lower back.