Abdol-Mohammad Kajbafzadeh, M.D. Maryam Ebadi, M.D. Pediatric Urology Research Center Pediatric Center of Excellence Tehran University of Medical Sciences Tehran, Iran Ali Tourchi, M.D. Division of Pediatric Urology Brady Urological Institute The Johns Hopkins Medical Institutions Baltimore, MD References 1. Ebadi M, Kajbafzadeh AM, Tourchi A, Mousvian AA. Endoureter- otomy as the initial management of concurrent ureteropelvic and ureterovesical junction obstruction after failed conservative therapy. Urology. 2013;82:214-219. 2. Kajbafzadeh AM, Tourchi A. Concomitant endoureterotomy and dextranomer/hyaluronic acid subureteral injection for management of obstructive refluxing megaureter. J Endourol. 2012;26:318-324. 3. Kajbafzadeh AM, Tourchi A, Bazargani S, Nezami BG. Single inci- sion miniature pyeloplasty and ipsilateral inguinal herniorrhaphy in infants. J Urol. 2010;183:1545-1549. 4. Kajbafzadeh AM, Tourchi A, Nezami BG, et al. Miniature pyelo- plasty as a minimally invasive surgery with less than 1 day admission in infants. J Pediatr Urol. 2011;7:283-288. 5. Kajbafzadeh AM, Tourchi A, Ebadi M. The outcome of initial endoscopic treatment in the management of concomitant ves- icoureteral reflux and ureteropelvic junction obstruction. Urology. 2013;81:1040-1045. 6. Kajbafzadeh AM, Tourchi A, Ebadi M. Reply. Urology. 2013;81:1046. 7. Pesce C, Musi L, Campobasso P, et al. Coexisting pelviureteral and vesicoureteral junction obstruction in children. Eur J Pediatr Surg. 2003;13:367-371. 8. Moodley P, Demaria J, Lorenzo AJ, et al. Concurrent ureteropelvic and ureterovesical junction obstruction in children: the value of retrograde pyelography. J Pediatr Urol. 2010;6:117-121. Re: Okhunov et al.: S.T.O.N.E. Nephrolithometry: Novel Surgical Classification System for Kidney Calculi (Urology 2013;81:1154-1160) TO THE EDITOR: We read this article 1 with interest about size, tract length, obstruction, number of involved calyces, and essence (S.T.O.N.E.) nephrolithometry scoring system that gives an estimate regarding stone clearance rate and compli- cation rate after percutaneus nephrolithotomy (PCNL) and helps to improve patient counseling, surgical plan- ning, and uniform academic reporting. Additional vali- dation of this scoring system is important to confirm its general applicability for PCNL, as there are few points that need further evaluation. First, the authors have given radio-dense calculi (>950 Hounsfield unit ) higher scoring. However, according to the published reports 2 and in our experience, stones that are radiolucent or have lesser density have a greater chance of postoperative residue, and we believe that such stones should be given higher score. Other studies, however, show that stone composition does not affect outcome in PCNL. 3 Second, it is difficult to do PCNL in compact or undilated system and also in severely dilated system, as there are chances of amplatz sheath displacement. So, scoring should be 1 in mild to moderate dilation and 2 in undilated or severely dilated system; although further studies are needed to clarify this. There is some confusion regarding nephrolithometry score (minimum 5 and maximum 13) in the article. In the discussion and also in Figure 2, the range of score has been shown as 4-11 (which is probably a typographical error). Further studies are needed to make the scoring system better accounting for surgeon’s experience, renal anatomy, which seems to be a major factor determining stone clearance and complications. Kuldeep Sharma, M.B.B.S., M.S., D.N.B. (General Surgery) Apul Goel, M.B.B.S., M.S., M.Ch. (Urology), D.N.B. (Urology) Saurabh Gupta, M.B.B.S., M.S. (General Surgery) Department of Urology King George Medical University Lucknow, Uttar Pradesh, India References 1. Okhunov Z, Friedlander IJ, George AK, et al. S.T.O.N.E. neph- rolithometry: novel surgical classification system for kidney calculi. Urology. 2013;81:1154-1160. 2. Gücük A, Uyetürk U, Oztürk U, et al. Does the Hounsfield unit value determined by computed tomography predict the outcome of percutaneous nephrolithotomy? J Endourol. 2012;26:792-796. 3. Tracy CR, Gupta A, Pearle MS, et al. Calcium phosphate content does not affect stone-free rate after percutaneous nephrolithotomy. J Urol. 2012;187:169-172. Reply by the Authors TO THE EDITOR: The S.T.O.N.E. nephrolithometry scoring system was created with 2 primary objectives; to standardize the comparison of management for nephrolithiasis and provide an additional insight from preoperative factors that may affect treatment outcome. With these goals in mind, taking into account the limited adoption of previous models, we sought to provide a simple scoring system with variables that would not only provide infor- mation of perioperative outcomes, but also impart detailed information regarding individual cases relevant to clinical decision making. There have been limited studies elucidating the effect of radiodensity on percutaneous nephrolithotomy (PCNL) outcomes, although previous studies have shown that stone composition can affect the outcomes of UROLOGY 82 (4), 2013 979