Department of Urology, China Medical University Hospital, Taichung, Taiwan.
School of Medicine, China Medical University, Taichung, Taiwan; Department of Urology, An-Nan Hospital, Tainan, Taiwan.
J Urol. 2016 Jul;196(1):33-40. doi: 10.1016/j.juro.2016.01.092. Epub 2016 Jan 25.
We proposed a mathematical formula to calculate contact surface area between a tumor and renal parenchyma. We examined the applicability of using contact surface area to predict renal function after partial nephrectomy.
We performed this retrospective study in patients who underwent partial nephrectomy between January 2012 and December 2014. Based on abdominopelvic computerized tomography or magnetic resonance imaging, we calculated the contact surface area using the formula (2πradius*depth) developed by integral calculus. We then evaluated the correlation between contact surface area and perioperative parameters, and compared contact surface area and R.E.N.A.L. (Radius/Exophytic/endophytic/Nearness to collecting system/Anterior/Location) score in predicting a reduction in renal function.
Overall 35, 26 and 45 patients underwent partial nephrectomy with open, laparoscopic and robotic approaches, respectively. Mean ± SD contact surface area was 30.7±26.1 cm(2) and median (IQR) R.E.N.A.L. score was 7 (2.25). Spearman correlation analysis showed that contact surface area was significantly associated with estimated blood loss (p=0.04), operative time (p=0.04) and percent change in estimated glomerular filtration rate (p <0.001). On multivariate analysis contact surface area and R.E.N.A.L. score independently affected percent change in estimated glomerular filtration rate (p <0.001 and p=0.03, respectively). On ROC curve analysis contact surface area was a better independent predictor of a greater than 10% change in estimated glomerular filtration rate compared to R.E.N.A.L. score (AUC 0.86 vs 0.69).
Using this simple mathematical method, contact surface area was associated with surgical outcomes. Compared to R.E.N.A.L. score, contact surface area was a better predictor of functional change after partial nephrectomy.
我们提出了一个数学公式来计算肿瘤与肾实质之间的接触面积。我们检验了使用接触面积预测部分肾切除术后肾功能的适用性。
我们对 2012 年 1 月至 2014 年 12 月期间接受部分肾切除术的患者进行了这项回顾性研究。根据腹部盆腔计算机断层扫描或磁共振成像，我们使用积分微积分公式计算接触面积（2π半径*深度）。然后，我们评估了接触面积与围手术期参数之间的相关性，并比较了接触面积和 R.E.N.A.L.（半径/外生/内生/靠近收集系统/前/位置）评分在预测肾功能下降方面的作用。
共有 35 例、26 例和 45 例患者分别接受了开放、腹腔镜和机器人辅助部分肾切除术。平均（标准差）接触面积为 30.7（26.1）cm2，中位数（IQR）R.E.N.A.L.评分 7（2.25）。Spearman 相关分析显示，接触面积与估计失血量（p=0.04）、手术时间（p=0.04）和估计肾小球滤过率的变化百分比（p <0.001）显著相关。多元分析显示，接触面积和 R.E.N.A.L.评分独立影响估计肾小球滤过率的变化百分比（p <0.001 和 p=0.03）。在 ROC 曲线分析中，与 R.E.N.A.L.评分相比，接触面积是估计肾小球滤过率变化超过 10%的更好的独立预测因子（AUC 0.86 与 0.69）。
使用这种简单的数学方法，接触面积与手术结果相关。与 R.E.N.A.L.评分相比，接触面积是部分肾切除术后功能变化的更好预测因子。
