A total of 18 studies with 1,362 patients met our inclusion criteria, including 566 patients in early series (Table 8.2) and 796 in contemporary series (Table 8.3). Of these, 90 patients were the result of “prospective” series with SFRs based on CT scan follow-up (see Table 8.3). Both of these (prospective randomized controlled trial Pearle et al. [12] and prospective trial Portis et al. [13]) are reviewed in greater detail in discussion section of this chapter. The remaining 16 studies were retrospective in nature and report a wide range of non-standardized follow-up protocols. It is important to note a significant lack of uniformity in outcome reporting among all trials. Therefore, SFRs from these studies were quite variable and have a high potential for bias and unreliability. Seven studies used more than one imaging modality to calculate SFR without stratifying patients per that modality, consequently making results unclear [14–20]. CT was the imaging modality of choice in 4/9 “modern” series (see Table 8.3), while kidneys–ureters–bladder films (KUB) the most common radiograph in the early series (7/9 studies, Table 8.2). Detection of residual stone burdens solely by CT scan was performed by three groups [12, 13, 21], while CT was combined with a variety of imaging modalities in two studies [15, 18]. Five studies have been published with a focus primarily on ureteroscopic treatment of lower pole stones (Tables 8.2 and 8.3) [12, 15, 22–24]. Four of these studies were published prior to widespread use of ureteral access sheaths in 2003, and two investigated patients who had previously failed SWL and/or had residual stones following PCNL [17, 25].

Using data from Tables 8.2 and 8.3, we created early and contemporary URS, Figs. 8.1 and 8.2. The number of patients was taken from each tabled study and multiplied by their reported SFR. These were summed and divided by total number of patients from all included studies, yielding an average. For example, five studies were reported before 2003 with a mean stone size <1 cm [14, 20, 22–24]. Total patient number multiplied by SFR and divided by total patient number resulted in the following: [(47  ×  0.94)  +  (100  ×  0.77)  +  (59  ×  0.80)  +  (78  ×  0.76)  +  (60  ×  0.79)/(47  +  100  +  59  +  78  +  60)], equaling 79.9% which rounded to 80% (Fig. 8.1). All reported SFRs are termed “unadjusted” as they are pooled samples from a variety of studies and imaging modalities. Any use of imaging other than strict CT criteria (i.e., studies that combined CT and a variety of other imaging modalities) was termed “multiple imaging modality” or MIM.