Cadeddu J A, Bzostek A, Schreiner S, Barnes A C, Roberts W W, Anderson J H, Taylor R H, Kavoussi L R
James Buchanan Brady Urological Institute and the Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, Maryland 21224, USA.
J Urol. 1997 Oct;158(4):1589-93.
Percutaneous renal access can be challenging, particularly when the collecting system is not distended. Precise entry into a selected calyx facilitates subsequent percutaneous manipulations, but this skill requires extensive experience. In an attempt to improve accuracy while decreasing technical challenges, we developed a robotic system that automates the task of fluoroscopic image-guided percutaneous needle placement.
The prototype system consisted of a three degree-of-freedom robot with a needle injector end-effector. Imaging was provided by a biplanar fluoroscope. After correction of image distortion and fluoroscope calibration, robot to image-space registration was completed. To validate the system's ability to insert a needle into a calyx, ex vivo porcine kidneys suspended in agarose gel and distended with iodinated contrast solution were used as a model. In situ renal access tests with three 20 kg. pigs were performed. Access was confirmed by passing a flexible wire or aspirating iodinated contrast from the collecting system.
The diameter of target calyces ranged from 3 to 7 mm. The in vitro accuracy of final needle tip positioning was 0.43 mm. In the ex vivo model, successful "one stick" access occurred on 10 of 12 attempts (83%). In situ access on the first attempt was successful for 6 of 12 target calyces (50%). Needle or tissue deflection accounted for each failure.
The feasibility of a robotic system to assist in the percutaneous access of small and delicate renal calyces has been demonstrated. Additional work in reducing procedural steps and correcting for tissue deflection during needle passage is necessary to improve accuracy and to allow for clinical application.
经皮肾穿刺入路可能具有挑战性，尤其是当集合系统未扩张时。精确进入选定的肾盏有助于后续的经皮操作，但这项技术需要丰富的经验。为了提高准确性并减少技术挑战，我们开发了一种机器人系统，该系统可自动执行荧光透视图像引导下经皮穿刺针放置任务。
原型系统由一个带有针注射末端执行器的三自由度机器人组成。成像由双平面荧光透视仪提供。在纠正图像失真和荧光透视仪校准后，完成机器人到图像空间的配准。为了验证该系统将针插入肾盏的能力，使用悬浮在琼脂糖凝胶中并用碘化造影剂溶液扩张的离体猪肾作为模型。对三头20千克的猪进行了原位肾穿刺入路测试。通过插入一根柔性导丝或从集合系统中抽吸碘化造影剂来确认穿刺入路。
目标肾盏的直径范围为3至7毫米。最终针尖定位的体外精度为0.43毫米。在离体模型中，12次尝试中有10次（83%）成功实现“一次穿刺”入路。12个目标肾盏中有6个（50%）在首次尝试时原位穿刺成功。每次失败均是由于针或组织发生偏转而导致。
已证明机器人系统辅助经皮进入小而脆弱的肾盏的可行性。为了提高准确性并实现临床应用，有必要在减少操作步骤以及纠正针通过期间的组织偏转方面开展更多工作。
