[Management of renal calix calculosis]

A FREQUENT PROBLEM: Lithiases in the urinary tract form first in the calices, raising complex problems of lithogenesis. As described by Randall, in males caliceal lithiases are often composed of calcium oxalate, generally as a monohydrate. In females, calcium phosphate stones are common, stones related to urease-producing germs are less frequent, and the bi-hydrated form of calcium oxalate predominates.

Caliceal lithiases can remain asymptomatic and are often discovered fortuitously. Symptoms include chronic lower back pain or urinary tract infections. Regular surveillance is required due to the risk of local growth into a more or less voluminous complex lithiasis. Misleading digestive tract or rhumatatism-like recurrent pain may result from local migration. Other stones descend spontaneously creating the specific problems of ureteral lithiasis.

Consensus is still lacking on renal mapping, predominant chemical make-up, and measurement of caliceal lithiases. These three criteria must be carefully studied to achieve a rigorous widely-accepted classification scheme allowing comparisons between proposed management protocols. The classification should use simple and low-cost imaging techniques: plain x-rays remain the gold standard although spiral computed tomography provides a more complete, though more costly, analysis.

Regular surveillance is indicated for asymptomatic caliceal lithases measuring less than 5 mm whatever the localization within the kidney. Symptomatic caliceal lithiases measuring less than 20 mm should be treated with first intention extracorporeal lithotripsy. Certain stones with known composition (cystine) resist external shock waves and certain lower or intradiverticular caliceal stones may require a more aggressive approach with percutaneous surgery or ureterorenoscopic endocorporeal lithotripsy. Combination treatment using percutaneous and extracorporeal techniques should be used for large stones (> 20 mm) or for stones lying in an abnormal urinary tract. The goal of all treatments for caliceal stones is to eliminate all residual fragments and collect all eliminated or extracted fragments for physical (intrared spectrophotometry) and non-chemical analysis of the different constituents to establish an adapted management scheme aimed at preventing recurrence.