Modeling and preoperative planning for kidney surgery

6    Chapter 1 Introduction Kidney surgery is a common and complex procedure. The procedure is required to remove kidney tumors and to treat a variety of renal malfunctions. Nowadays, a minimally invasive approach is the method of choice for partial nephrectomy operations. This procedure presents many challenges to the surgeon stemming from the kidney anatomy and the nature of the minimal invasive technique. Preoperative planning based on Computed Tomography (CT) scans is a crucial step, since it can reduce the risk of the procedures and decrease their duration. Many of the surgical decisions can be pre-determined in the preoperative planning stage. Today, surgeons perform preoperative planning by browsing through CT slices and constructing a mental representation of the kidney, its internal components and their spatial relations, and planning the surgery accordingly. This approach is time-consuming, incomplete, and inaccurate. This thesis describes semi-automatic methods for the creation of patient-specific kidney models from four-phase CT studies. The kidney models include the kidney outer contour, kidney arteries, veins, urine collecting system and tumors when present. The models are incorporated into a preoperative planning system that allows the surgeon to visualize the kidney and its internal components and to position a resection plane. 1.1. Anatomy background We begin with a brief description of the kidney anatomy and its relative location in the body. The kidneys are a pair of organs lying on either side of the vertebral column between the peritoneum and the back wall of the abdominal cavity at the level of the 12 th thoracic and first three lumbar vertebrae. The right kidney is slightly lower than the left because the liver occupies a large area above the kidney in the right side. Figure 1 shows the kidneys location in the body.