Long-term results of endourologic treatment of urinary calculi: investigation of risk factors for recurrence or regrowth.

To evaluate the risk factors related to the long-term outcome of endourologic treatment of urinary calculi, we examined rates of recurrence and regrowth in 167 renal units. The following risk factors were examined: age; previous stone; location, number, size, and composition of stone; and procedures. In our study sample, the overall recurrence and regrowth rates were 17% and 10%, respectively. The earliest recurrence and regrowth appeared at 3 months after treatment, and 71% occurred within 2 years. In 22% of renal units that were estimated to be stone-free, stones appeared later, and 45% of inadequately fragmented stones enlarged. Stones located in a renal calix and pelvis, multiple stones, large stones (more than 20 mm), stones composed of calcium oxalate or calcium phosphate or both, and struvite stones were likely to be risk factors, but there were no significant differences statistically. Although the possibility of several risk factors was suggested in our study, thorough fragmentation of stones and complete removal of fragments, combined with extracorporeal shock wave lithotripsy or chemolysis if needed, is ultimately responsible for successful treatment of urinary calculi.