Assessment of Intraoperative Liver Deformation During Hepatic Resection: Prospective Clinical Study

Abstract

Background The implementation of intraoperative navigation in liver surgery is handicapped by intraoperative organ shift, tissue deformation, the absence of external landmarks, and anatomical differences in the vascular tree. To investigate the impact of surgical manipulation on the liver surface and intrahepatic structures, we conducted a prospective clinical trial. Methods Eleven consecutive patients [4 female and 7 male, median age = 67 years (range = 54-80)] with malignant liver disease [colorectal metastasis (n = 9) and hepatocellular cancer (n = 2)] underwent hepatic resection. Pre-and intraoperatively, all patients were studied by CT-based 3D imaging and assessed for the potential value of computer-assisted planning. The degree of liver deformation was demonstrated by comparing pre-and intraoperative imaging. Results Intraoperative CT imaging was successful in all patients. We found significant deformation of the liver. The deformation of the segmental structures is reflected by the observed variation of the displacements. There is no rigid alignment of the pre-and intraoperative organ positions due to overall deflection of the liver. Locally, a rigid alignment of the anatomical structure can be achieved with less than 0.5 cm discrepancy relative to a segmental unit of the liver. Changes in total liver volume range from -13 to ?24%, with an average absolute difference of 7%. Conclusions These findings are fundamental for further development and optimization of intraoperative navigation in liver surgery. In particular, these data will play an important role in developing automation of intraoperative continuous registration. This automation compensates for liver shift during surgery and permits real-time 3D visualization of navigation imaging.

Estimation of External Forces on the Basis of Local Displacement Observations of an Elastic Body

“…We regard local displacement as a known quantity because deformation measurement methods are often available, such as measurement of surface deformation of elastic bodies using camera images [2][3][4][5] and measurement of inner deformation using ultrasonography [6]. In this study, we assume that the known quantity u o includes the displacement of inner vertices.…”

“…This presents a possibility of error or medical malpractice including injury to organs or unexpected rupture of blood vessels from excess force. To remedy this, various intraoperative measurements and physical estimations of the deformed organs [2][3][4][5][6][7] have been attempted. Soft tissues, including organs, are deformed during surgery because of tensile forces exerted by the forceps, the progress of surgery, the state of pneumoperitoneum, and the breath of the patient.…”

“…Soft tissues, including organs, are deformed during surgery because of tensile forces exerted by the forceps, the progress of surgery, the state of pneumoperitoneum, and the breath of the patient. Image processing studies such as feature point extraction methods using 3D endoscopes [2][3][4][5] have been attempted to measure the deformation of organs. In addition, ultrasonography is usually used for specifying the location of tumors and is helpful in measuring deformation [6].…”

Special considerations of living liver donor transplantation

“…Habár a radiológiai leírások jelentős része a normális májanatómiát taglalja, egyes tanulmányok rávilágítanak az intraoperatív manipulációk okozta változásokra (torzulások, torquatiók stb. ), amelyek jelentős mértékben befolyásolhatják az élődono-ros transzplantációk sikerét [24]. Az anatómiai vizsgá-latok további tökéletesítéséhez, a vena hepaticákhoz és a vena portae ágrendszereihez tartozó territóriumok kalkulációjához a MeVis szoftver elengedhetetlen.…”

Biomechanically Driven Registration of Pre- to Intra-Operative 3D Images for Laparoscopic Surgery

“…To bridge the gap between surgical plans and laparoscopic images, registration of pre-and intra-operative 3D images is needed to guide real time navigation. However, this registration is challenging due to gas insufflation [1] and other surgical preparation [2], which result in large organ deformation and sliding between viscera and abdominal wall (Fig. 1).…”