Management of concurrent asymptomatic small ipsilateral or contralateral renal stones during the primary stone surgery is often debatable. Recently, Sorenson et al, reported a RCT comparing active Rx with URS vs observation for small asymptomatic stones in patients undergoing either PCNL or URSL.(1) The authors randomised 75 patients into Rx arm (URS for ipsilateral or contralateral small asymptomatic stones) or observation and followed them for 5years for relapse, which was defined as either of the following: visit to ED for pain, surgical intervention or growth of stone >1mm on follow up CT scan. 16% patients in Rx arm had relapse as compared to 63% in observation arm (p<0.001) and the mean time to relapse was much longer in the Rx arm (1631 days vs 934 days). Excluding the criteria of stone growth, the relapse rate still remained higher in the control arm (11% vs 43%). Besides, the additional intervention only added 25min to the surgical time and the immediate complication rate was similar. The patient reported stone passage rate, rate of new stone formation and the mean time to new stone formation was similar between the two groups. These findings are in sharp contrast with seminal prospective study that evaluated prophylactic ESWL for small asymptomatic calyceal stones and did not find an advantage, forming the basis of most of the guidelines.(2) However, with advent of flexible URS, these results may no longer be applicable. Two other retrospective studies have reported benefit in terms of relapse and re-intervention rates.(3,4) However, in absence of large scale prospective studies, the benefits of Rx asymptomatic stones must be balanced against the possibility of over-intervention, spontaneous passage of stone and new stone formation.
Figure 1: In Focus: Management of Asymptomatic Secondary Renal Stone