Re: Assessing the Usefulness of Delayed Imaging in Routine Followup for Renal Trauma P. Davis, M. F. Bultitude, J. Koukounaras, P. L. Royce and N. M. Corcoran J Urol 2010; 184: 973–977. To the Editor: This article is intriguing, and it brings up many good points on the usefulness of routine renal imaging after initial computerized tomography for renal injury staging. While it is a well-done study, I have concerns regarding some of the conclusions that were derived. The authors state that progression on routine imaging was seen in only 1 of 108 patients, although only 30 patients had grade 4 or 5 injuries. It is common practice to reimage only grade 4 and 5 renal injuries, so the yield of reimaging is 1 of 30 (3.3%), not 1 of 108 (0.9%). Furthermore, of the 7 patients who progressed 5 had grade 3 injuries, 1 grade 4 and 1 grade 5. Again, it is not standard practice to reimage grades 1 to 3. Also, mean time to repeat imaging in this study was 26 days in the routine imaging arm and 17 days in the symptomatic arm. Thus, we are not speaking here of eliminating reimaging at even 72 hours in grade 4 and 5 renal injuries, but rather the value of imaging at 2 and 4 weeks. It would have been more meaningful if the authors had reported the median time from injury to repeat scan instead of the mean time, as the range of times was wide (4 to 240 days for group 1 and 3 to 45 days for group 2). To determine a more specific time (cutoff) where delayed imaging has little value, multivariate statistical analysis would need to be performed. While Altman et al reported that highly select grade 5 renal injuries can safely be managed conservatively, 1 the original American Association for the Surgery of Trauma grading scale essentially defined grade 5 injuries as life threatening, 2 thus warranting angiography or surgical intervention as initial management. We are sending the wrong message to the urological community that such injuries should routinely be managed conservatively. Moreover, I suspect that many of these “shattered” kidneys that were labeled grade 5 would actually be reclassified as grade 4 if an independent reviewer restaged them. Historically the progression and nonreso- lution rates of grade 4 renal injuries are 9% to 12%, while in this study the grade 4 progression and nonresolution rates are only 2.7% (1 of 37) and 7.1% (1 of 14), in grade 5. Why the marked differences? With such a low progression rate, I suspect the grade 5 injuries were overgraded. What is most surprising is that the highest rates of progression were for grade 3 injuries, at 8.9% (5 of 56). I am not sure how to explain this finding. It just raises red flags as to the accuracy of the staging of renal injuries in this study. Respectfully, Lawrence L. Yeung and Steven B. Brandes Department of Surgery Division of Urologic Surgery Washington University School of Medicine St. Louis, Missouri Reply by Authors: Yeung and Brandes raise a number of points that need to be addressed. First, it is suggested that we exclude grades 1 to 3 injuries from the calculation for progression. While certainly grades 1 and 2 do not require repeat imaging, in our series 5 patients with grade 3 injuries had progression, and therefore this cohort merits analysis. This evaluation then gives a progression rate of 1.4% (1 of 69) for routinely imaged patients. Although we accept that an appropriate denominator may be debatable, the numerator is still 1, which is the point we are trying to make. The article also makes it quite clear that we are not examining the usefulness of repeat scanning at 48 to 72 hours for high grade injuries. The study looks at the usefulness of imaging after this initial period. This is a poorly researched area and one that the European Association of Urology guidelines on trauma suggest requires analysis. 3 The article also clearly states that repeat imaging was not protocol driven, but rather reflects the real-life management of renal trauma cases at our institution. Median followup imaging was at 24.5 days and 16.5 days for LETTERS TO THE EDITOR/ERRATA 759