Diagnostic morphologic and urodynamic antegrade pyelography.

Diagnostic antegrade pyelography, with a thin needle, is basically a simple procedure that can be performed relatively rapidly under local anesthesia with few complications of significance. Its role, however, is frequently crucial to subsequent patient management. During morphologic antegrade examination, aspirated urine can be analyzed for tumor cells (cytologic examination), infection (smear, culture), or other biochemical alterations. The use of antegrade pyelography in the demonstration of internal diversion, ureteral fistula, and the site and cause of obstruction is well established. Dynamic antegrade study is crucial in the assessment of many pyeloureteral units in which the issue of current obstruction is equivocal or uncertain. Absolute renal and bladder pressures are obtained simultaneously; these and the calculated differential pressure provide objective data relative to ureteral resistance to urine flow and renal nephron preservation.