Renal collecting system anatomy: its possible role in the effectiveness of renal stone treatment.

The anatomy of the kidney collecting system may play a role in the selection of the best method of kidney stone treatment for a specific patient. Also, an analysis of the collecting-system anatomy would indicate the likely effectiveness of each method of treatment. For stones located in the lower pole, the clearance rate after shockwave lithotripsy has been uniformly low relative to that of calculi elsewhere. Some special anatomical findings suggest that retention of what are considered to be 'passable stone fragments' (4 mm in diameter or less) in the inferior pole might be a consequence not only of the gravity-dependent position of lower calices but also of particular anatomical features of the inferior pole collecting system. The aspects reviewed and discussed are the angle formed between the main lower infundibulum and the renal pelvis (the infundibulopelvic angle), the lower infundibula diameters, the lower infundibulum length and height, and the lower calices spatial distribution. Also, the presence of minor calices perpendicular to the surface of the collecting system and drainage of superior and inferior poles are reviewed and discussed in the context of their importance to the effectiveness of renal stone treatment.