This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Not true about congenital PUJ obstruction is - \nSelect and explain. \nA. Can be associated with renal agenesis, B. Can be diagnosed antenatally, C. b/l in 10 - 15% of cases, D. Abberant vessels is the most common cause.', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 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."\nCambells Urology writes - "whether the aberrant vessel causes obstruction or is a co variable that exists along with an intrinsic narrowing is unclear"\n\nImportant points about Congenital PELT obstruction \n\nCong. PUJ obstruction is the most common cause of significant dilatation of the collecting system in the fetal kidney.\nIncidence is more in boys (2:1)\nUsually 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 D)\nMore common in left side\nAssociated anomalies -\n\n\n\nRenal dysplasia\nMulticystic dysplastic kidney\nRenal agenesis\n\n(Cambell urology writes - "Unilateral renal agenesis has been noted in almost 5% of children")\n\nVescico - ureteric reflux\nPUJ obstruction was noted in 21% of children with the VATER group of anomalies\n\n\n(VATER stands for vertebral defects, imperforate anus, tracheoesophageal fistula, radial and renal dysplasia)\nMost common presentation of cong. PUJ obstruction is asymptomatic. Cambell writes - " Now the almost\nuniversal use of prenatal sonography has made discovery of PUJ obstruction a common occurance"\n\nDiagnostic tools -\n\nMajority of cases are diagnosed prenatally with the help of ultrasound.\nWhitaker test (pressure - flow studies) can be used to find out obstruction to flow of urine,\nIn 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.\nRetrograde pyelography can be useful to locate the site of obstruction.\n\nSurgical repair\n\nCongenital PUJ obstruction are corrected by either-open surgical techniques or -endoscopic and laparascopic approaches\nOut of the \'open\' techniques the Anderson- Hynes Dismembered Pyeloplasty is the most commonly employed technique.\nEndoscopic approaches include,\nendoscopic pyelotomy\nballon dilatation\nstent placement', 'role': 'assistant'}]