Tirapegui Federico Ignacio, González Mariano Sebastian, González Ignacio Pablo Tobía, Daels Francisco P
Urology Department, Hospital Italiano de Buenos Aires , Buenos Aires, Argentina .
J Endourol. 2015 Jun;29(6):666-70. doi: 10.1089/end.2014.0410. Epub 2014 Dec 2.
To identify kidney stone characteristics that will determine either success or failure of a percutaneous nephrolithotomy (PCNL) and design a classification system to predict results according to these characteristics.
One hundred thirty-eight patients were assessed with multislice abdominal and pelvic CT before and after PCNL. With regard to pyelocaliceal stone distribution, we classified our patients in two groups that we called "no extra stone in middle calix" (NESMC) and "extra stone in middle calix" (ESMC), according to the difficulty in reaching the stones. We did a univariate and a multivariate analysis, as well as a receiving operating curve (ROC) of the proposed classification, based on the foreseen probabilities, to determine the diagnostic yield.
Global residual lithiasis (RL) was 26.08%. The proportion of patients with RL according to classification was NESMC 11.5% and ESMC 59.5%. In the univariate logistic regression analysis of the distribution, number, total volumetry, side, type, radio-opacity of stones, and the presence or not of preoperatory urinary tract infection, the variables related to RL were the distribution (11.3; 95% confidence interval [95% CI] 4.7, 27.4), volumetry (odds ratio [OR] 1.01; 95% CI 1.004, 1.014), and the presence of staghorn stones (OR 6.64; 95% CI 2.463, 17.905). In the multivariate analysis, distribution was statistically significant (OR 8.687; 95% CI 2.69, 28.06), whereas total volumetry and the presence of staghorn stones were not (OR 1; 95% CI 1.000, 1.000 and OR 2.7; 95% CI 0.35, 20.57, respectively). The ROC showed an area under the curve of 0.77.
In our experience, the distribution of kidney stones is the most important predictor of RL after PCNL. The results also suggest that the presence of stones in the middle calix has a direct impact on the stone-free rate. We put forward a simple and reproducible classification, easy to apply, and useful to estimate the chances of success of the procedure using preoperatory CT scans.
确定能够决定经皮肾镜取石术（PCNL）成败的肾结石特征，并设计一种分类系统，根据这些特征预测手术结果。
对138例患者在PCNL术前和术后进行多层腹部及盆腔CT检查。关于肾盂肾盏结石分布，根据结石取石难度，将患者分为两组，即“中盏无额外结石”（NESMC）组和“中盏有额外结石”（ESMC）组。我们进行了单因素和多因素分析，并根据预测概率对所提出的分类进行了接受操作曲线（ROC）分析，以确定诊断率。
总体残余结石（RL）率为26.08%。根据分类，NESMC组患者的RL比例为11.5%，ESMC组为59.5%。在对结石的分布、数量、总体积、侧别、类型、不透X线程度以及术前是否存在尿路感染进行单因素逻辑回归分析时，与RL相关的变量为分布（11.3；95%置信区间[95%CI]4.7，27.4）、体积（比值比[OR]1.01；95%CI1.004，1.014）以及鹿角形结石的存在（OR6.64；95%CI2.463，17.905）。在多因素分析中，分布具有统计学意义（OR8.687；95%CI2.69，28.06），而总体积和鹿角形结石的存在则无统计学意义（分别为OR1；95%CI1.000，1.000和OR2.7；95%CI0.35，20.57）。ROC曲线下面积为0.77。
根据我们的经验，肾结石分布是PCNL术后RL的最重要预测因素。结果还表明，中盏结石的存在对无石率有直接影响。我们提出了一种简单且可重复的分类方法，易于应用，有助于利用术前CT扫描评估手术成功的几率。
