Morphologic changes following nephrostomy track dilatation. An experimental investigation in the pig

The effect on the renal parenchyma caused by rapid dilatation of a nephrostomy track to 24 F to 30 F was studied on 9 kidneys in 5 pigs. Angiography at different intervals up to 5 weeks was used in combination with histology. Moderate bleeding and short lacerations were observed around the puncture site in all kidneys. Complications included one transient pyelovenous reflux, one organized abscess following perforation of the upper pole, and two cases of hydronephrosis caused by abscess and inflammation. These infections were probably due to the prevailing sanitary conditions. No arteriovenous fistula formation was seen. Minimal scars were encountered after 4 to 5 weeks follow-up. Transparenchymal access to the pelvocaliceal system through percutaneously established large tracks seems to cause limited damage which resolves in minor scars provided perforations are avoided by an optimum technique and infections are prevented or treated appropriately.