Division of Urology, Hospital das Clinicas, University of Sao Paulo Medical School, Sao Paulo, Brazil.
Stevan B. Streem Center for Endourology & Stone Disease, Glickman Urological & Kidney Institute, The Cleveland Clinic, Cleveland, Ohio.
J Endourol. 2020 Jan;34(1):63-67. doi: 10.1089/end.2019.0545. Epub 2019 Nov 21.
Lower pole kidney stones have been associated with poor shock wave lithotripsy (SWL) outcomes because of its location. However, the real impact of collecting system anatomy on stone clearance after SWL is uncertain. There is a lack of prospective well-controlled studies to determine whether lower pole kidney stones have inferior outcomes than nonlower pole kidney stones when treated with SWL. We prospectively evaluated patients with a single kidney stone of 5-15 mm undergoing SWL from June 12 through January 19. All patients were subjected to computed tomography before and 3 months after the procedure. Demographic data (age, gender, and body mass index), stone features (stone size, stone area, stone density, and stone-skin distance-SSD), and collecting system anatomy (infundibular length and width, and infundibulopelvic angle) were recorded. Outcomes (fragmentation and stone clearance rates) were compared between lower pole and nonlower pole cases. Then, a multivariate analysis including all variables was performed to determinate which parameters significantly impact on SWL outcomes. One hundred and twenty patients were included in the study. Mean stone size was 8.3 mm and mean stone density was 805 Hounsfield units. Overall stone fragmentation, success, and stone-free rates were 84.1%, 64.1%, and 34.1%, respectively. There were no significant differences in stone fragmentation (76.0% 71.4%; = 0.624), success rate (57.6% 53.3%; = 0.435), and stone-free rate (40.2% 35.7%; = 0.422) in the lower nonlower pole groups, respectively. On multivariate analysis, only stone density ( < 0.001) and SSD ( = 0.006) significantly influenced fragmentation. Stone size ( = 0.029), stone density ( = 0.002), and SSD ( = 0.049) significantly influenced kidney stone clearance. Stone size, stone density, and SSD impact on SWL outcomes. Lower pole kidney stones have similar fragmentation and stone clearance compared with nonlower pole kidney stones.
下极肾结石由于其位置与较差的冲击波碎石（SWL）结果相关。然而，SWL 后收集系统解剖对结石清除的实际影响尚不确定。缺乏前瞻性对照研究来确定在接受 SWL 治疗时，下极肾结石的结果是否劣于非下极肾结石。
我们前瞻性评估了 12 年 6 月 12 日至 19 年 1 月期间接受 SWL 的单个 5-15mm 肾结石患者。所有患者均在术前和术后 3 个月进行计算机断层扫描。记录人口统计学数据（年龄、性别和体重指数）、结石特征（结石大小、结石面积、结石密度和结石-皮肤距离-SSD）和收集系统解剖结构（漏斗长度和宽度以及漏斗-肾盂角度）。比较下极和非下极病例的结局（碎裂和结石清除率）。然后，进行了包括所有变量的多变量分析，以确定哪些参数对 SWL 结果有显著影响。
研究纳入了 120 例患者。平均结石大小为 8.3mm，平均结石密度为 805 豪斯菲尔德单位。总的结石碎裂、成功和无石率分别为 84.1%、64.1%和 34.1%。在碎裂率（76.0% 71.4%； = 0.624）、成功率（57.6% 53.3%； = 0.435）和无石率（40.2% 35.7%； = 0.422）方面，下极和非下极组之间无显著差异。多变量分析显示，只有结石密度（ < 0.001）和 SSD（ = 0.006）显著影响碎裂。结石大小（ = 0.029）、结石密度（ = 0.002）和 SSD（ = 0.049）显著影响肾结石清除率。
结石大小、结石密度和 SSD 影响 SWL 结果。下极肾结石与非下极肾结石的碎裂和结石清除率相似。
