You mention the your sister has symptoms of back pain
. The ultrasonogram has shown that the right kidney
is grossly enlarged (normal 9-11cm, but 16cm in her case). The DTPA renogram shows an obstructed drainage
In a symptomatic patient it is always better to go for surgical treatment
. Unfortumately there is no medical treatment for this condition. It can be explained in a simple mechanical example where in the out flow pipeline is blocked and there is enlarged kidney as a result of the pressure built up.
If you can remove the blocade then it will help at this stage especially because the relative function of the kidney despite being hydronephrotic is still at 34% which is good. You can preserve the kidney function if the surgery is done at this stage.
You can consider a laparoscopic surgery
if you are not interested in an open procedure. This will have good results and less scarring.
Hope it was helpful.