Purpose: Three-dimensional (3D) surgical planning is widely accepted in liver surgery. Currently, the 3D reconstructions are usually presented as 3D PDF data on regular monitors. 3D-printed liver models are sometimes used for education and planning. Methods: We developed an immersive virtual reality (VR) application that enables the presentation of preoperative 3D models. The 3D reconstructions are exported as STL files and easily imported into the application, which creates the virtual model automatically. The presentation is possible in “OpenVR”-ready VR headsets. To interact with the 3D liver model, VR controllers are used. Scaling is possible, as well as changing the opacity from invisible over transparent to fully opaque. In addition, the surgeon can draw potential resection lines on the surface of the liver. All these functions can be used in a single or multi-user mode. Results: Five highly experienced HPB surgeons of our department evaluated the VR application after using it for the very first time and considered it helpful according to the “System Usability Scale” (SUS) with a score of 76.6%. Especially with the subitem “necessary learning effort,” it was shown that the application is easy to use. Conclusion: We introduce an immersive, interactive presentation of medical volume data for preoperative 3D liver surgery planning. The application is easy to use and may have advantages over 3D PDF and 3D print in preoperative liver surgery planning. Prospective trials are needed to evaluate the optimal presentation mode of 3D liver models.

Virtual reality and 3D printing improve preoperative visualization of 3D liver reconstructions—results from a preclinical comparison of presentation modalities and user’s preference Florentine Huettl, Patrick Saalfeld, Christian Hansen, Bernhard Preim, Alicia Poplawski, Werner Kneist, Hauke Lang, Tobias Huber

Introduction: Due to technological changes, working time restrictions and the creation of specialized centers, surgical training has changed. A competence‐based learning technique of surgical skills is the sub‐step practice approach, which has been proven important in nationwide opinion surveys. The aim of this prospective multi‐center trial was to determine the status quo of the sub‐step concept in Germany. Methods: Over 6 months, the voluntarily participating centers evaluated the following index procedures: laparoscopic cholecystectomy (LCHE), laparoscopic and open sigmoid resection, minimally invasive inguinal hernia repair, thyroid resection and pylorus‐preserving pancreaticoduodenectomy (PPPD). Patients with private insurance were excluded. The detailed sub‐steps were documented as well as the reason why these were not performed. In addition, an online survey regarding the sub‐step concept was performed before and after the study. Results: In total, 21 centers included 2969 surgical procedures in 2018 for final analyses. While 24.4% of the procedures were performed by residents, sub‐steps were performed in 22.2%. LCHE was most often performed completely by residents (43.3%), and PPPD revealed the highest rate of performed sub‐steps (43.3%). Reasons for not assisting sub‐steps to residents were often organizational and other reasons. After an initial increase, the number of performed sub‐steps decreased significantly during the second half of the survey. The opinion survey revealed a high importance of the sub‐step concept. The number of resident procedures was overestimated, and the number of performed sub‐steps was underestimated. After the study, these estimations were more realistic. Conclusion: Even though the sub‐step practice concept is considered highly important for surgical education, it needs to be put into practice more consequently. The current data suggest a low participation of surgical residents in the operating room, although the participating hospitals are most likely highly interested in surgical education, hence their voluntary participation. Conceptual changes and a control of surgical education are needed.

Primary hepatic angiosarcoma (PHA) is a rare tumor entity. Radical surgical resection is currently considered the best treatment choice. The aim of this analysis is to report our experience with surgery for PHA. All resections of PHA from 01/2002 until 06/2017 were identified from our prospective institutional database. All cases were re-confirmed by a second pathologist. We analyzed completeness of resection, overall (OS) and disease-free survival (DFS). Nine patients with PHA underwent hepatic resection. Median follow-up after surgery was 15.5 months (range: 3–144). At last follow-up 4/9 patients were alive, three of them without recurrence 15, 21 and 144 months after surgery. Five patients developed PHA recurrence. Four of these died 3 to 17 months after surgery. One patient with PHA recurrence is alive 15 months after surgery. Another patient without PHA recurrence died 59 months after surgery from pancreatic cancer. Median OS and DFS after resection was 18 months (range: 3–144 months) and 10 months (range: 2–144 months), respectively. After R-0 resection (n = 8), the median OS and DFS was 59 and 11 months. Resection of PHA is the only approach to achieve complete tumor removal and offers a chance for long-term survival and should be evaluated in cases of PHA.

Background: Liver surgery is the standard of care for primary and many secondary liver tumors. Due to variability and complexity in liver anatomy preoperative imaging is necessary to determine resectability and for planning the surgical strategy. In the last few years, computer-assisted resection planning has been introduced in liver surgery. Aim of this trial was the evaluation of computer-assisted three-dimensional (3D)-navigation for liver surgery. Methods: This study was a prospective randomized-controlled pilot trial and patients were randomized in navigated or non-navigated group. Primary end point was the quotient of intraoperative resected volume and planned resection volume. Secondary end points included operation time, resection margin and postoperative complications. 3D reconstructions were performed with MeVis Distant Services (MeVis AG, Bremen, Germany). The navigation system CAS-One Liver (CAScination AG, Bern, Switzerland) was used for intraoperative computer-assisted 3D-navigation. Results: The data of 16 patients with 20 liver tumors were used in this analysis. Of these, 8 liver tumors were resected with the utilization of intraoperative navigation. Two postoperative complications were classified grade IIIa or higher. There was no difference in duration of operation (189 vs. 180 min, P=0.970), rate of postoperative complications (n=1 vs. n=1, P=0.696) and length of hospital stay (9 vs. 7 days, P=0.368) between the two groups. Minimal resection margin (0.15 vs. 0.40 cm, P=0.384) and quotient of planned to intraoperative resection volume (0.94 vs. 1.11, P=0.305) were also similar. Conclusions: Intraoperative navigation is a technology that can be safely used during liver resection. Surgical accuracy is not yet superior to the current standard of intraoperative orientation. Further technological advances with suitable deformation algorithms and augmented reality systems will enable a further improvement of the technical feasibility.