<prompt> Not true about congenital PUJ obstruction is -Can be associated with renal agenesisCan be diagnosed antenatallybl in 10 - 15 of casesAbberant vessels is the most common cause.  <response>: It was earlier believed that the aberrant renal vessels is responsible for causing the cong. PUJ obstruction Bailey writes that - Aberrant vessels probably do not cause hydronephrosis, although a hydronephrotic renal pelvis may bulge between renal vessels.Cambells Urology writes - whether the aberrant vessel causes obstruction or is a co variable that exists along with an intrinsic narrowing is unclearImportant points about Congenital PELT obstruction Cong. PUJ obstruction is the most common cause of significant dilatation of the collecting system in the fetal kidney.Incidence is more in boys 2:1Usually unilateral but bilateral in 10-40 of cases I could not find 10-15 of cases, but option C can be taken as correct, weighing it against option DMore common in left sideAssociated anomalies -Renal dysplasiaMulticystic dysplastic kidneyRenal agenesisCambell urology writes - Unilateral renal agenesis has been noted in almost 5 of childrenVescico - ureteric refluxPUJ obstruction was noted in 21 of children with the VATER group of anomaliesVATER stands for vertebral defects, imperforate anus, tracheoesophageal fistula, radial and renal dysplasiaMost common presentation of cong. PUJ obstruction is asymptomatic. Cambell writes - Now the almostuniversal use of prenatal sonography has made discovery of PUJ obstruction a common occuranceDiagnostic tools -Majority of cases are diagnosed prenatally with the help of ultrasound.Whitaker test pressure - flow studies can be used to find out obstruction to flow of urine,In whitaker test catheters are placed in renal pelvis and bladder. Fluid is infused into the kidney and the pressures are measured. A differential pressure between kidney and bladder could then be indicative of obstruction to the flow.Retrograde pyelography can be useful to locate the site of obstruction.Surgical repairCongenital PUJ obstruction are corrected by either-open surgical techniques or -endoscopic and laparascopic approachesOut of the open techniques the Anderson- Hynes Dismembered Pyeloplasty is the most commonly employed technique.Endoscopic approaches include,endoscopic pyelotomyballon dilatationstent placement 