9. Differential function (DF) of less than 40%.
Symptoms attributable to a UPJO.
A washout curve greater than T1/2 > 20 min, if in conjunction with poor
function or symptoms.
Associated with calyceal dilatation, thinned parenchyma: severe
anteroposterior (AP) diameter > 40 mm (even with symmetric function).
10. Do you perform a VCUG if the pre-
operative RUS appears to be a typical
UPJ obstruction?
11. What features make you suspect an
extrinsic cause of obstruction?
Do you perform any addition preoperative
investigations in this situation?
13. What is your approach to UPJO with <10%
function on renogram?
Do you perform an initial nephrostomy or insert a
double J (DJ) stent to assess recoverability of
function?