Re: Clinically Insignificant Residual Fragments After Percutaneous Nephrolithotomy: Medium-Term Follow-Up (From: Altunrende F,Tefekli A,Stein RJ,et al. J Endourol 2011;25:941–945)

Dear Editor:

We congratulate the authors for this study. We have a few queries. Although the authors mention that in spite of metabolic abnormalities they did not use any medical therapy for those with a metabolic abnormality, what was the reason behind this approach because the data show decreased stone recurrence in patients with such abnormalities after medical management? ^{1 –3} The authors mention an increase in stone size in eight patients at follow-up of at least 24 months but do not mention the mean (or range) increase in stone size. This information would help us to know the rate of growth of these residual fragments.

Three patients spontaneously passed the fragment after percutaneous nephrolithotomy (PCNL). What was the time duration after which the stone was expelled? This information is important because data regarding how long to wait for spontaneous expulsion after extracorporeal shockwave lithotripsy is available in the literature but not after PCNL.

Lastly, the authors mention in the results of the Abstract that stone size was stable or “decreased” in 27 (71%) without any further mention about decrease in the results. Is it really possible for stone size to decrease without any medical management (as in the present study)?