Bodenstedt Sebastian, Wagner Martin, Mayer Benjamin, Stemmer Katherine, Kenngott Hannes, Müller-Stich Beat, Dillmann Rüdiger, Speidel Stefanie
Institute for Anthropomatics and Robotics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
Department of General, Visceral and Transplant Surgery, University of Heidelberg, Heidelberg, Germany.
Int J Comput Assist Radiol Surg. 2016 Mar;11(3):407-19. doi: 10.1007/s11548-015-1291-1. Epub 2015 Sep 26.
Minimally invasive interventions offer benefits for patients, while also entailing drawbacks for surgeons, such as the loss of depth perception. Thus estimating distances, which is of particular importance in gastric bypasses, becomes difficult. In this paper, we propose an approach based on stereo endoscopy that segments organs on-the-fly and measures along their surface during a minimally invasive interventions. Here, the application of determining the length of bowel segments during a laparoscopic bariatric gastric bypass is the main focus, but the proposed method can easily be used for other types of measurements, e.g., the size of a hernia.
As input, image pairs from a calibrated stereo endoscope are used. Our proposed method is then divided into three steps: First, we located structures of interest, such as organs and instruments, via random forest segmentation. Two modes of instrument detection are used. The first mode is based on an automatic segmentation, and the second mode uses input from the user. These regions are then reconstructed, and the distance along the surface of the reconstruction is measured. For measurement, we propose three methods. The first one is based on the direct distance of the instruments, while the second one finds the shortest path along a surface. The third method smooths the shortest path with a spline interpolation. Our measuring system is currently one shot, meaning a signal to begin a measurement is required.
To evaluate our approach, data sets from multiple users were recorded during minimally invasive bowel measurements performed on phantoms and pigs. On the phantom data sets, the overall average error was [Formula: see text] on shorter pieces of bowel ([Formula: see text]5 cm) and [Formula: see text] on longer pieces ([Formula: see text]10 cm). On the porcine data sets, the average error was [Formula: see text].
We present and evaluate a novel approach that makes measuring on-the-fly during minimally invasive surgery possible. Furthermore, we compare different methods for determining the length of bowel segments. The only requirement for our approach is a calibrated stereo endoscope, thereby keeping the impact on the surgical workflow to a minimum.
微创干预对患者有益，但对外科医生也有不利之处，比如会丧失深度感知。因此，在胃旁路手术中尤为重要的距离估计变得困难。在本文中，我们提出一种基于立体内窥镜的方法，该方法在微创干预过程中实时分割器官并沿其表面进行测量。在此，腹腔镜减肥胃旁路手术中确定肠段长度的应用是主要关注点，但所提出的方法可轻松用于其他类型的测量，例如疝气的大小。
作为输入，使用来自校准立体内窥镜的图像对。我们提出的方法随后分为三个步骤：首先，我们通过随机森林分割定位感兴趣的结构，如器官和器械。使用两种器械检测模式。第一种模式基于自动分割，第二种模式使用用户输入。然后对这些区域进行重建，并测量沿重建表面的距离。对于测量，我们提出三种方法。第一种基于器械的直接距离，第二种找到沿表面的最短路径。第三种方法用样条插值平滑最短路径。我们的测量系统目前是单次测量，即需要一个开始测量的信号。
为了评估我们的方法，在对 phantom 和猪进行的微创肠测量过程中记录了多个用户的数据集。在 phantom 数据集上，较短肠段（≤5 厘米）的总体平均误差为[公式：见原文]，较长肠段（≥10 厘米）为[公式：见原文]。在猪数据集上，平均误差为[公式：见原文]。
我们提出并评估了一种新颖的方法，该方法使在微创手术期间实时测量成为可能。此外，我们比较了确定肠段长度的不同方法。我们的方法唯一的要求是校准的立体内窥镜，从而将对外科手术流程的影响降至最低。
