Park Byung-Hun, Choi Hoon, Kim Jin-Bum, Chang Young-Seop
Department of Urology, Konyang University College of Medicine, Daejeon, Korea.
Korean J Urol. 2012 Jan;53(1):40-3. doi: 10.4111/kju.2012.53.1.40. Epub 2012 Jan 25.
To determine whether the distance from skin to stone, as measured by computed tomography (CT) scans, could affect the stone-free rate achieved via extracorporeal shock wave lithotripsy (ESWL) in renal stone patients.
We retrospectively reviewed the records 573 patients who had undergone ESWL at our institution between January 2006 and January 2010 for urinary stones sized from about 5 mm to 20 mm and who had no evidence of stone movement. We excluded patients with ureteral catheters and percutaneous nephrostomy patients; ultimately, only 43 patients fulfilled our inclusion criteria. We classified the success group as those patients whose stones had disappeared on a CT scan or simple X-ray within 6 weeks after ESWL and the failure group as those patients in whom residual stone fragments remained on a CT scan or simple X-ray after 6 weeks. We analyzed the differences between the two groups in age, sex, size of stone, skin-to-stone distance (SSD), stone location, density (Hounsfield unit: HU), voltage (kV), and the number of shocks delivered.
The success group included 33 patients and the failure group included 10. In the univariate and multivariate analysis, age, sex, size of stone, stone location, HU, kV and the number of shocks delivered did not differ significantly between the two groups. Only SSD was a factor influencing success: the success group clearly had a shorter SSD (78.25±12.15 mm) than did the failure group (92.03±14.51 mm). The results of the multivariate logistic regression analysis showed SSD to be the only significant independent predictor of the ESWL stone-free rate.
SSD can be readily measured by CT scan; the ESWL stone-free rate was inversely proportional to SSD in renal stone patients. SSD may therefore be a useful clinical predictive factor of the success of ESWL on renal stones.
通过计算机断层扫描（CT）测量皮肤到结石的距离，确定其是否会影响肾结石患者体外冲击波碎石术（ESWL）的结石清除率。
我们回顾性分析了2006年1月至2010年1月在我院接受ESWL治疗的573例患者的记录，这些患者的尿路结石大小约为5毫米至20毫米，且无结石移动迹象。我们排除了输尿管插管患者和经皮肾造瘘患者；最终，只有43例患者符合纳入标准。我们将成功组定义为ESWL治疗后6周内结石在CT扫描或简单X线检查中消失的患者，失败组定义为6周后CT扫描或简单X线检查中仍有残留结石碎片的患者。我们分析了两组在年龄、性别、结石大小、皮肤到结石距离（SSD）、结石位置、密度（亨氏单位：HU）、电压（kV）和冲击波次数方面的差异。
成功组包括33例患者，失败组包括10例。在单因素和多因素分析中，两组在年龄、性别、结石大小、结石位置、HU、kV和冲击波次数方面无显著差异。只有SSD是影响成功的因素：成功组的SSD（78.25±12.15毫米）明显短于失败组（92.03±14.51毫米）。多因素逻辑回归分析结果显示，SSD是ESWL结石清除率的唯一重要独立预测因素。
CT扫描可轻松测量SSD；肾结石患者的ESWL结石清除率与SSD成反比。因此，SSD可能是ESWL治疗肾结石成功的有用临床预测因素。
