Percutaneous nephrolithotripsy: a functional and morphological study.

Percutaneous removal of renal calculi requires a nephrostomy track, irrigation and lithotripsy. The purpose of this study is to investigate the effects of these procedures on renal function and anatomy. Renal access was obtained through a small left subcostal incision and a 22 Ch nephrostomy track was formed by fine parenchymal puncture and serial dilation in 15 dogs. Three liters of glycine solution were perfused through these tracks. In a further 16 dogs, human calculi were placed transparenchymally in the renal pelvis and disintegrated under vision through the Wolf nephroscope using an ultrasonic probe in 8 and electrohydraulic probe in 8. Assessments were made in all animals at 48 hours or 6 weeks by creatinine clearance, microfil casts, contrast radiography and ex-situ conventional and digital subtraction angiography. There was no significant urinary leakage or bleeding from the nephrostomy track at 48 hours. There was a small track hematoma and at 6 weeks a surface dimple and fine linear parenchymal scar. There was no ureteric or pelvic damage. Microfil casts showed small track defects at 48 hours resolving to a fine scar at 6 weeks. All angiograms were normal. Some IVU's displayed minor track defects at 48 hours but all were normal at 6 weeks. Corrosion casts and subtraction angiography demonstrated no significant vascular defects. Creatinine clearance showed no significant difference between experimental and control sides. Occasionally, intra pelvic scatter of fine calculus fragments was seen at 48 hours but none was detectable at 6 weeks. Transparenchymal nephrostomy, irrigation and nephrolithotripsy caused initial minor anatomical defects that rapidly resolved and were not associated with any loss of renal function.