Immersive virtual reality for interdisciplinary trauma management - initial evaluation of a training tool prototype.

INTRODUCTION: Emergency care of critically ill patients in the trauma room is an integral part of interdisciplinary work in hospitals. Live threatening injuries require swift diagnosis, prioritization, and treatment; thus, different medical specialties need to work together closely for optimal patient care. Training is essential to facilitate smooth performance. This study presents a training tool for familiarization with trauma room algorithms in immersive virtual reality (VR), and a first qualitative assessment. MATERIALS AND METHODS: An interdisciplinary team conceptualized two scenarios and filmed these in the trauma room of the University Medical Center Mainz, Germany in 3D-360°. This video content was used to create an immersive VR experience. Participants of the Department of Anesthesiology were included in the study, questionnaires were obtained and eye movement was recorded. RESULTS: 31 volunteers participated in the study, of which 10 (32,2%) had completed specialist training in anesthesiology. Participants reported a high rate of immersion (immersion(mean) = 6 out of 7) and low Visually Induced Motion Sickness (VIMS(mean) = 1,74 out of 20). Participants agreed that VR is a useful tool for medical education (mean = 1,26; 1 very useful, 7 not useful at all). Residents felt significantly more secure in the matter after training (p < 0,05), specialist showed no significant difference. DISCUSSION: This study presents a novel tool for familiarization with trauma room procedures, which is especially helpful for less experienced residents. Training in VR was well accepted and may be a solution to enhance training in times of low resources for in person training.

[Evidence, Availability and Future Visions in Simulation in General and Visceral Surgery]. / Evidenz, Verfügbarkeit und Zukunftsvisionen der Simulation in der Allgemein- und Viszeralchirurgie.

Practice makes perfect - a saying that everyone has certainly heard. Surgeons of all levels of training can demonstrably practice to some extent on simulators. This training outside the operating theatre and independent of patients makes sense, both ethically and financially. Although the effectiveness of simulation in surgery has been proven several times, simulation training is not a mandatory part of surgical specialist training in Germany. Simulation covers a very wide range in terms of application, effort and costs. This review is intended to give an overview of the systems and their areas of application and the target group. The focus lies on the commonly available systems and possible advantages and disadvantages. Practical skills are in the foreground and all three pillars of general and visceral surgery - conventional techniques, laparoscopy and robotics - are taken into account. However, simulators alone do not achieve cost-benefit effectiveness. The full potential of such an investment can only be exploited with a site-specific, structured training concept in which simulation training according to the post-graduate year and appropriate allocation to surgeries in the operating room are closely interlinked. It should always be possible to train basic skills on site. The significant additional costs for complex simulation systems are possible, depending on the financial resources, or should be purchased in a network or for national courses. The techniques of immersive virtual reality in combination with artificial intelligence and deformation algorithms will certainly play a decisive role for the future of simulation, whereby the use of the available systems must be a primary goal. The integration of simulation into specialist training should be striven for, not least in order to justify the costs.

[Liver Surgery 4.0 - Planning, Volumetry, Navigation and Virtual Reality]. / Leberchirurgie 4.0 - OP-Planung, Volumetrie, Navigation und Virtuelle Realität.

Due to the optimisation of conservative treatment, the improvement of imaging methods and the continuous development of surgical techniques, the borders of resectability in liver surgery have changed significantly in recent decades.Thanks to numerous technical developments, in particular three-dimensional segmentation, preoperative planning and orientation during the operation itself, can now be facilitated, especially in complex procedures.New technologies such as 3D printing as well as virtual and augmented reality offer additional display options for the patients' individual anatomy. Various intraoperative navigation options are intended to make preoperative planning available in the operating room in order to increase patient safety.This review article is intended to provide an overview of the current state of available technologies and an outlook into the operating theatre of the future.

Experiences With Three-dimensional Printing in Complex Liver Surgery.

OBJECTIVE: We present a series of cases where we used 3D printing in planning of complex liver surgery. BACKGROUND: In liver surgery, three-dimensional reconstruction of the liver anatomy, in particular of vascular structures, has shown to be helpful in operation planning. So far, 3D printing has been used for medical applications only rarely. METHODS AND PATIENTS: From December 2017 to December 2019, in 10 cases where surgery was assumed to be challenging operation planning was performed using full size 3D prints in addition to standard 3 phase CT scans. Models included transparent parenchyma, hepatic veins, vena cava, portal vein, hepatic artery, (biliary tree if requested), and tumors. In 7/10 cases vascular reconstructions were needed during the procedure. Nonstructured feedback of the surgical team revealed that the major benefit was visualization of the critical areas of vascular reconstruction, the expected dimensions of tangential vascular infiltration and the planning of reconstruction. In the multifocal tumors, 3D prints were considered to be helpful for intraoperative orientation to detect metastases and to improve planning of the resection. CONCLUSIONS: In complex liver surgery with potential need for vascular reconstructions operation planning may be optimized using a 3D printed liver model. Prospective studies are needed to evaluate the clinical impact of 3D printing in liver surgery compared to other 3D visualizations.

Using virtual 3D-models in surgical planning: workflow of an immersive virtual reality application in liver surgery.

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.

[Surgical Education in the Digital Age - Virtual Reality, Augmented Reality and Robotics in the Medical School]. / Chirurgische Ausbildung im digitalen Zeitalter ­ Virtual Reality, Augmented Reality und Robotik im Medizinstudium.

BACKGROUND: The digital transformation of healthcare is changing the medical profession. Augmented/Virtual Reality (AR/VR) and robotics are being increasingly used in different clinical contexts and require supporting education and training, which must begin within the medical school. There is currently a large discrepancy between the high demand and the number of scientifically proven concepts. The aim of this thesis was the conceptual design and structured evaluation of a newly developed learning/teaching concept for the digital transformation of medicine, with a special focus on the influence of surgical teaching. METHODS: Thirty-five students participated in three courses of the blended learning curriculum "Medicine in the digital age". The 4th module of this course deals with virtual reality, augmented reality and robotics in surgery. It is divided into the following course parts: (1) immersive surgery simulation of a laparoscopic cholecystectomy, (2) liver surgery planning using AR/VR, (3) basic skills on the VR simulator for robotic surgery, (4) collaborative surgery planning in virtual space and (5) expert discussion. After completing the overall curriculum, a qualitative and quantitative evaluation of the course concept was carried out by means of semi-structured interviews and standardised pre-/post-evaluation questionnaires. RESULTS: In the qualitative evaluation procedure of the interviews, 79 text statements were assigned to four main categories. The largest share (35%) was taken up by statements on the "expert discussion", which the students consider to be an elementary part of the course concept. In addition, the students perceived the course as a horizon-widening "learning experience" (29% of the statements) with high "practical relevance" (27%). The quantitative student evaluation shows a positive development in the three sub-competences knowledge, skills and attitude. CONCLUSION: Surgical teaching can be profitably used to develop digital skills. The speed of the change process of digital transformation in the surgical specialty must be considered. Curricular adaptation should be anchored in the course concept.

Local, semi-automatic, three-dimensional liver reconstruction or external provider? An analysis of performance and time expense.

PURPOSE: In hepatobiliary surgery, preoperative three-dimensional reconstruction based on CT or MRI can be provided externally or by local, semi-automatic software. We analyzed the time expense and quality of external versus local three-dimensional reconstructions. METHODS: Three first-year residents reconstructed data from 20 patients with liver pathologies using a local, semi-automatic, server-based program. Initially, five randomly selected patient datasets were segmented, with the visualization of an established external company available for comparison at all times (learning phase). The other fifteen cases were compared with the external datasets after completing local reconstruction (control phase). Total time expense/case and for specific manual and semi-automated reconstruction steps were recorded. Segmentation quality was analyzed by testing the equivalence for liver and tumor volumes, portal vein sectors, and hepatic vein territories. RESULTS: The median total reconstruction time was reduced from 2.5 h (learning phase) to 1.5 h (control phase) (- 42%; p < 0.001). Comparing the total and detailed liver volumes (sectors and territories) as well as the tumor volumes in the control phase equivalence was proven. In addition, a highly significant correlation between the external and local analysis was obtained over all analyzed segments with a very high ICC (median [IQR]: 0.98 [0.97; 0.99]; p < 0.01). CONCLUSION: Local, semi-automatic reconstruction performed by inexperienced residents was feasible with an expert level time expense and the quality of the three-dimensional images was comparable with those from an external provider.

Quality-based assessment of camera navigation skills for laparoscopic fundoplication.

Laparoscopic fundoplication is considered the gold standard surgical procedure for the treatment of symptomatic hiatus hernia. Studies on surgical performance in minimally invasive hiatus hernia repair have neglected the role of the camera assistant so far. The current study was designed to assess the applicability of the structured assessment of laparoscopic assistance skills (SALAS) score to laparoscopic fundoplication as an advanced and commonly performed laparoscopic upper GI procedure. Randomly selected laparoscopic fundoplications (n = 20) at a single institute were evaluated. Four trained reviewers independently assigned SALAS scoring based on synchronized video and voice recordings. The SALAS score (5-25 points) consists of five key aspects of laparoscopic camera navigation as previously described. Experience in camera assistance was defined as at least 100 assistances in complex laparoscopic procedures. Nine different surgical teams, consisting of five surgical residents, three fellows, and two attending physicians, were included. Experienced and inexperienced camera assistants were equally distributed (10/10). Construct validity was proven with a significant discrimination between experienced and inexperienced camera assistants for all reviewers (P < 0.05). The intraclass correlation coefficient of 0.897 demonstrates the score's low interrater variability. The total operation time decreases with increasing SALAS score, not reaching statistical significance. The applied SALAS score proves effective by discriminating between experienced and inexperienced camera assistants in an upper GI surgical procedure. This study demonstrates the applicability of the SALAS score to a more advanced laparoscopic procedure such as fundoplication enabling future investigations on the influence of camera navigation on surgical performance and operative outcome.

Higher quality camera navigation improves the surgeon's performance: Evidence from a pre-clinical study.

INTRODUCTION: To objectively assess the quality of laparoscopic camera navigation (LCN), the structured assessment of LCN skills (SALAS) score was developed and validated for laparoscopic cholecystectomy. The aim of this pre-clinical study was to investigate the influence of LCN on surgical performance during virtual cholecystectomy (vCHE) using this score. METHODS: A total of 84 medical students were included in this prospective study. Individual characteristics were assessed with questionnaires. Participants completed a structured 2-day training course on a validated virtual reality laparoscopic simulator. At the end of the course, all students took over LCN during vCHE, all performed by the same surgeon. The numbers of errors regarding centering, horizon adjustment and instrument visualisation as well as manual and verbal corrections by the surgeon were recorded to calculate the SALAS score (range 5-25) to investigate the influence of LCN on surgical performance. The study population was divided by the recorded SALAS score into low and medium performers (Group A; 1st-3rd quartile; n = 60) and high performers (Group B, 4th quartile, n = 21). RESULTS: The SALAS score of the camera assistant correlates positively with the surgeon's overall performance in vCHE (P < 0.001), and the surgeon's virtual laparoscopic performance was significantly better in Group B (P < 0.001). Moreover, a significantly shorter operation time during vCHE was shown for Group B (Median (IQR); Group A: 508 s [429 s; 601 s]; Group B: 422 s [365 s; 493 s]; P = 0.001). Frequent gaming and a higher self-confidence to assist during a basic laparoscopic procedure were associated with a higher SALAS score (P = 0.013). CONCLUSION: In this pre-clinical setting, the surgeon's virtual performance is significantly influenced by the LCN quality. LCN by high performers resulted in a shorter operation time and a lower error rate.

[Right Trisectionectomy and Hilar Resection with Resection and Reconstruction of the Portal Vein Bifurcation and Left Hepatic Vein in Cholangiocellular Carcinoma]. / Erweiterte Hemihepatektomie rechts mit Hepatikusgabelresektion und Rekonstruktion der Pfortadergabel und der linken Lebervene bei cholangiozellulärem Karzinom.

Complete surgical resection of intrahepatic cholangiocellular carcinoma is considered the primary option for curative treatment. With tumour extension, resection and reconstruction of vascular structures can be necessary. Three dimensional planning of surgical resection can be useful in selected cases. The current video shows an extended right sided hemihepatectomy with hilar resection and reconstruction of the left portal vein and one of two branches of the left hepatic vein in a patient with intrahepatic cholangiocarcinoma.

Real-Time Augmented Reality Annotation for Surgical Education during Laparoscopic Surgery: Results from a Single-Center Randomized Controlled Trial and Future Aspects.

BACKGROUND: We developed an interactive augmented reality tool (HoloPointer) that enables real-time annotation on a laparoscopy monitor for intraoperative guidance. This application operates exclusively via verbal commands and head movements to ensure a sterile workflow. STUDY DESIGN: Purpose of this randomized controlled clinical trial was to evaluate the integration of this new technology into the operating room. This prospective single-center study included 32 elective laparoscopic cholecystectomies (29 surgical teams, 15 trainees, and 13 trainers). The primary objective and assessment measure was the HoloPointer's influence on surgical performance (subjective assessment, global operative assessment of laparoscopic skills [GOALS] and critical view of safety [CVS]). The secondary objectives and outcome variables were its influence on operation time, quality of assistance (5-point Likert scale), and user-friendliness (system usability scale, 0 to 100 points). RESULTS: Gestural corrections were reduced by 59.4% (4.6 SD 8.1 vs 1.9 SD 4.7, p > 0.05) and verbal corrections by 36.1% (17.8 SD 12.9 vs 11.4 SD 8.1, p > 0.05). Subjective surgical performance could be improved by 84.6% of participants. No statistically significant differences were observed for objective parameters GOALS, CVS, and operation time. In the system usability scale, the application achieved an average score of 72.5 SD 16.3 (good user-friendliness). Of the participants, 69.2% wanted to use the HoloPointer more frequently. CONCLUSIONS: The majority of trainees improved their surgical performance using the HoloPointer in elective laparoscopic cholecystectomies, and the rate of classic but potentially misleading corrections was noticeably reduced. The HoloPointer has the potential to improve education in minimally invasive surgery.

A comparison of input devices for precise interaction tasks in VR-based surgical planning and training.

To exploit the potential of virtual reality (VR) in medicine, the input devices must be selected carefully due to their different benefits. In this work, input devices for common interaction tasks in medical VR planning and training are compared. Depending on the specific purpose, different requirements exist. Therefore, an appropriate trade-off between meeting task-specific requirements and having a widely applicable device has to be found. We focus on two medical use cases, liver surgery planning and craniotomy training, to cover a broad medical domain. Based on these, relevant input devices are compared with respect to their suitability for performing precise VR interaction tasks. The devices are standard VR controllers, a pen-like VR Ink, data gloves and a real craniotome, the medical instrument used for craniotomy. The input devices were quantitatively compared with respect to their performance based on different measurements. The controllers and VR Ink performed significantly better than the remaining two devices regarding precision. Qualitative data concerning task load, cybersickness, and usability and appropriateness of the devices were assessed. Although no device stands out for both applications, most participants preferred using the VR Ink, followed by the controller and finally the data gloves and craniotome. These results can guide the selection of an appropriate device for future medical VR applications.

HoloPointer: a virtual augmented reality pointer for laparoscopic surgery training.

PURPOSE: In laparoscopic surgery training, experts guide novice physicians to desired instrument positions or indicate relevant areas of interest. These instructions are usually given via verbal communication or using physical pointing devices. To facilitate a sterile work flow and to improve training, new guiding methods are needed. This work proposes to use optical see-through augmented reality to visualize an interactive virtual pointer on the laparoscopic. METHODS: After an interdisciplinary development, the pointer's applicability and feasibility for training was evaluated and it was compared to a standard condition based on verbal and gestural communication only. In this study, ten surgical trainees were guided by an experienced trainer during cholecystectomies on a laparoscopic training simulator. All trainees completed a virtual cholecystectomy with and without the interactive virtual pointer in alternating order. Measures included procedure time, economy of movement and error rates. RESULTS: Results of standardized variables revealed significantly improved economy of movement (p = 0.047) and error rates (p = 0.047), as well as an overall improved user performance (Total z-score; p = 0.031) in conditions using the proposed method. CONCLUSION: The proposed HoloPointer is a feasible and applicable tool for laparoscopic surgery training. It improved objective performance metrics without prolongation of the task completion time in this pre-clinical setup.

Virtual reality and 3D printing improve preoperative visualization of 3D liver reconstructions-results from a preclinical comparison of presentation modalities and user's preference.

BACKGROUND: Preoperative three-dimensional (3D) reconstructions for liver surgery planning have been shown to be effective in reduction of blood loss and operation time. However, the role of the 'presentation modality' is not well investigated. We present the first study to compare 3D PDFs, 3D printed models (PR) and virtual reality (VR) 3D models with regard to anatomical orientation and personal preferences in a high volume liver surgery center. METHODS: Thirty participants, 10 medical students, 10 residents, 5 fellows and 5 hepatopancreatobiliary (HPB) experts, assigned the tumor-bearing segments of 20 different patient's individual liver reconstructions. Liver models were presented in a random order in all modalities. Time needed to specify the tumor location was recorded. In addition, a score was calculated factoring in correct, wrong and missing segment assignments. Furthermore, standardized test/questionnaires for spatial thinking and seeing, vegetative side effects and usability were completed. RESULTS: Participants named significantly more correct segments in VR (P=0.040) or PR (P=0.036) compared to PDF. Tumor assignment was significantly shorter with 3D PR models compared to 3D PDF (P<0.001) or VR application (P<0.001). Regardless of the modality, HPB experts were significantly faster (24±8 vs. 35±11 sec; P=0.014) and more often correct (0.87±0.12 vs. 0.83±0.15; P<0.001) than medical students. Test results for spatial thinking and seeing had no influence on time but on correctness of tumor assignment. Regarding usability and user experience the VR application achieved the highest scores without causing significant vegetative symptoms and was also the most preferred method (n=22, 73.3%) because of the multiple functions like scaling and change of transparency. Ninety percent (n=27) stated that this application can positively influence the operation planning. CONCLUSIONS: 3D PR models and 3D VR models enable a better and partially faster anatomical orientation than reconstructions presented as 3D PDFs. User's preferred the VR application over the PR models and PDF. A prospective trial is needed to evaluate the different presentation modalities regarding intra- and postoperative outcomes.

Toward interprofessional team training for surgeons and anesthesiologists using virtual reality.

PURPOSE: In this work, a virtual environment for interprofessional team training in laparoscopic surgery is proposed. Our objective is to provide a tool to train and improve intraoperative communication between anesthesiologists and surgeons during laparoscopic procedures. METHODS: An anesthesia simulation software and laparoscopic simulation software are combined within a multi-user virtual reality (VR) environment. Furthermore, two medical training scenarios for communication training between anesthesiologists and surgeons are proposed and evaluated. Testing was conducted and social presence was measured. In addition, clinical feedback from experts was collected by following a think-aloud protocol and through structured interviews. RESULTS: Our prototype is assessed as a reasonable basis for training and extensive clinical evaluation. Furthermore, the results of testing revealed a high degree of exhilaration and social presence of the involved physicians. Valuable insights were gained from the interviews and the think-aloud protocol with the experts of anesthesia and surgery that showed the feasibility of team training in VR, the usefulness of the system for medical training, and current limitations. CONCLUSION: The proposed VR prototype provides a new basis for interprofessional team training in surgery. It engages the training of problem-based communication during surgery and might open new directions for operating room training.