Functional evaluation before stone surgery: Is it mandatory?

Functional evaluation of the renal unit has often been quoted as a standard practice for management of stone disease of the upper urinary tract. However, there is very little available evidence from the existing literature to directly support or refute this practice. Here we try to critically review the existing literature on related questions, put into perspective its clinical utility and attempt to rationalize the concept of functional evaluation in patients of renal stone disease in the contemporary era of minimally invasive surgery.