THIS EXHIBIT presents two techniques and demonstrates examples of their usefulness in diagnosis and treatment of hydronephrosis. Both are performed with local anesthesia and roentgenographic control.
Antegrade pyelography1 consists of pyelograms made after lumbar needle puncture of a hydronephrosis. Urine is aspirated through a 6 in. 18- or 19-gauge spinal needle, and urographic contrast medium is injected to outline the renal pelvis and ureter to the point of obstruction. It should be reserved for cases of large hydronephrosis in which the diagnosis cannot be made by conventional techniques.
Trocar nephrostomy2 (or pyelostomy), a logical sequel to this technique, consists of lumbar tap of a large hydronephrosis with a 12-gauge thin-walled needle through which polyethylene tubing is inserted to afford temporary urinary diversion. It should be reserved for large hydronephroses in which temporary drainage is desired without operative intervention before later definitive treatment.