Intrarenal access: 3-dimensional anatomical study.

In an attempt to determine the best route to puncture and access the kidney collecting system we studied 62, 3-dimensional polyester resin endocasts of the pelvicaliceal system together with the intrarenal vessels. A retrograde pyelogram was obtained, and the arterial and venous trees were injected with red and blue resins, respectively. When the resin was still in the gel state, the kidneys were positioned at 30 to 45 degrees and the collecting system was punctured under radioscopy. Since the resin is not opaque to x-ray the operator was not able to visualize the vessels while puncturing. After puncture, the needle was maintained in place, the contrast medium was removed and the pelvicaliceal system was filled with yellow resin. After the resin had set, the renal organic matter was corroded in acid and the endocast was obtained (with the needle in the original position). This type of preparation allowed us to examine the needle tract and the vessels damaged during the puncture. In the same kidney we punctured the superior pole, mid kidney and inferior pole. In some cases we also punctured the renal pelvis. We performed 104 punctures through an infundibulum, 39 through a fornix of a calix and 12 through the renal pelvis. Due to a high percentage of vascular lesions, intrarenal access through an infundibulum should be avoided. Also, renal pelvis puncture should be avoided. Regardless of the kidney region, puncture through a fornix of a calix was safe.