Outcomes of long-term follow-up of patients with conservative management of asymptomatic renal calculi.

OBJECTIVE

• To evaluate the long-term outcomes of patients undergoing observation of asymptomatic renal calculi.

PATIENTS AND METHODS

• This is a retrospective review of 50 patients with 85 stones undergoing observation with annual imaging from January 2005 to December 2009. • The incidences of spontaneous stone passage, stone progression and intervention were evaluated and assessed for statistical difference according to initial size and location of stone. • Percutaneous nephrolithotomy, shock wave lithotripsy and ureteroscopy were performed when patients developed complications from the stones.

RESULTS

• Patients were followed up for a mean of 46 months. Sixteen percent had bilateral stones and 38% had multiple stones. • The average stone size was 5.7 mm and 31%, 26% and 43% of the stones were located in the upper, middle and lower pole respectively. • Overall incidences of spontaneous passage, progression and intervention were 20%, 45.9% and 7.1% respectively. • Stones measuring 5 mm or less were significantly more likely to pass (P= 0.006). • There was no significant difference in the incidence of passage according to the initial location of the stone (P= 0.092). There was no significant difference in intervention or progression according to the initial size (P= 0.477 and 0.282 respectively) or location of stone (P= 0.068 and 0.787 respectively).

CONCLUSIONS

• Patients with asymptomatic renal stones may be managed conservatively in view of low risk of intervention (7.1%). • Annual imaging should be performed as half of these stones will progress in size.