Simulation of the abdominal wall and its arteries after pneumoperitoneum for guidance of port positioning in laparoscopic surgery

During laparoscopic surgery, the trocar insertion can injure arteries of the abdominal wall. Although these arteries are visible in a preoperative computed tomography [CT] with contrast medium, it is difficult for the surgeon to estimate their true intraoperative positions since the pneumoperitoneum dramatically stretches the abdominal wall. A navigation system showing the artery position would thus be very helpful for the surgeon. We present in this paper a method to simulate the position of the abdominal wall and its arteries after pneumoperitoneum. Our method requires a segmented preoperative CT image and an intraoperative surface reconstruction of the skin. The intraoperative skin surface allows us to compute a displacement field of the abdominal wall's outer surface that we propagate to estimate the artery position. Our simulation was evaluated using two sets of pig CT images, before and after pneumoperitoneum. Results show that our method provides an estimation of the abdominal wall and artery positions with an average error of respectively 2 mm and 6 mm which fits the clinical application constraint. In the near future, we will focus on viscera movement simulation after pneumoperitoneum using our abdominal wall shape prediction.