The problem of recurrences and infection after surgical removal of staghorn calculi.

A series of 99 consecutively operated patients presenting staghorn stones has been reviewed to ascertain the factors implicated in recurrent calculogenesis. 71.7% of the calculi were infection stones; 50.7% harbored Proteus species bacteria and 33.8% Escherichia coli. Struvite stones were found in 57.6% followed at long distance (18.2%) by carbonate apatite, calcium oxalate (11.1%) and mixed (9.1%) stones. Postoperative assessment revealed 17% residual stones, which enhanced infection in 46.7% of these cases and regrew to form a new dendritic stone in 33.3%; 80% of these repeat stones were struvite. 31.5% of the patients initially freed of their calculi by the operation, had true recurrences, and 56.5% of them had resistant urinary infection, caused by Proteus or E. coli (50%-50%). Progressive growth of the recurrent lithiasis occurred in 61.5% of the infected cases, while 87.5% of the recurrences occurring in patients with sterile urine remained stabilized. In the group of nonrecurring lithiasis (56.8%) only 16% had urinary infection. These results confirm the preponderant role played by infection in the pathogenesis of staghorn "malignant' lithiasis and move the authors to make a plea in favor of postoperative integrated therapy, including the use of long-term antibacterial agents and urease inhibitors.