Comparing a virtual reality head-mounted display to on-screen three-dimensional visualization and two-dimensional computed tomography data for training in decision making in hepatic surgery: a randomized controlled study.

OBJECTIVE: Evaluation of the benefits of a virtual reality (VR) environment with a head-mounted display (HMD) for decision-making in liver surgery. BACKGROUND: Training in liver surgery involves appraising radiologic images and considering the patient's clinical information. Accurate assessment of 2D-tomography images is complex and requires considerable experience, and often the images are divorced from the clinical information. We present a comprehensive and interactive tool for visualizing operation planning data in a VR environment using a head-mounted-display and compare it to 3D visualization and 2D-tomography. METHODS: Ninety medical students were randomized into three groups (1:1:1 ratio). All participants analyzed three liver surgery patient cases with increasing difficulty. The cases were analyzed using 2D-tomography data (group "2D"), a 3D visualization on a 2D display (group "3D") or within a VR environment (group "VR"). The VR environment was displayed using the "Oculus Rift ™" HMD technology. Participants answered 11 questions on anatomy, tumor involvement and surgical decision-making and 18 evaluative questions (Likert scale). RESULTS: Sum of correct answers were significantly higher in the 3D (7.1 ± 1.4, p < 0.001) and VR (7.1 ± 1.4, p < 0.001) groups than the 2D group (5.4 ± 1.4) while there was no difference between 3D and VR (p = 0.987). Times to answer in the 3D (6:44 ± 02:22 min, p < 0.001) and VR (6:24 ± 02:43 min, p < 0.001) groups were significantly faster than the 2D group (09:13 ± 03:10 min) while there was no difference between 3D and VR (p = 0.419). The VR environment was evaluated as most useful for identification of anatomic anomalies, risk and target structures and for the transfer of anatomical and pathological information to the intraoperative situation in the questionnaire. CONCLUSIONS: A VR environment with 3D visualization using a HMD is useful as a surgical training tool to accurately and quickly determine liver anatomy and tumor involvement in surgery.

Video-based training of situation awareness enhances minimally invasive surgical performance: a randomized controlled trial.

BACKGROUND: Many training curricula were introduced to deal with the challenges that minimally invasive surgery (MIS) presents to the surgeon. Situational awareness (SA) is the ability to process information effectively. It depends on general cognitive abilities and can be divided into three steps: perceiving cues, linking cues to knowledge and understanding their relevance, and predicting possible outcomes. Good SA is crucial to predict and avoid complications and respond efficiently. This study aimed to introduce the concept of SA into laparoscopic training. METHODS: This is a prospective, randomized, controlled study conducted at the MIS Training Center of Heidelberg University Hospital. Video sessions showing the steps of the laparoscopic cholecystectomy (LC) were used for cognitive training. The intervention group trained SA with interposed questions inserted into the video clips. The identical video clips, without questions, were presented to the control group. Performance was assessed with validated scores such as the Objective Structured Assessment of Technical Skills (OSATS) during LC. RESULTS: 72 participants were enrolled of which 61 were included in the statistical analysis. The SA-group performed LC significantly better (OSATS-Score SA: 67.0 ± 11.5 versus control: 59.1 ± 14.0, p value = 0.034) and with less errors (error score SA: 3.5 ± 1.9 versus control: 4.7 ± 2.0, p value = 0.027). No difference in the time taken to complete the procedure was found. The benefit assessment analysis showed no difference between the groups in terms of perceived learning effect, concentration, or expediency. However, most of the control group indicated retrospectively that they believed they would have benefitted from the intervention. CONCLUSION: This study suggests that video-based SA training for laparoscopic novices has a positive impact on performance and error rate. SA training should thus be included as one aspect besides simulation and real cases in a multimodal curriculum to improve the efficiency of laparoscopic surgical skills training.

Telestration with augmented reality improves surgical performance through gaze guidance.

BACKGROUND: In minimally invasive surgery (MIS), trainees need to learn how to interpret the operative field displayed on the laparoscopic screen. Experts currently guide trainees mainly verbally during laparoscopic procedures. A newly developed telestration system with augmented reality (iSurgeon) allows the instructor to display hand gestures in real-time on the laparoscopic screen in augmented reality to provide visual expert guidance (telestration). This study analysed the effect of telestration guided instructions on gaze behaviour during MIS training. METHODS: In a randomized-controlled crossover study, 40 MIS naive medical students performed 8 laparoscopic tasks with telestration or with verbal instructions only. Pupil Core eye-tracking glasses were used to capture the instructor's and trainees' gazes. Gaze behaviour measures for tasks 1-7 were gaze latency, gaze convergence and collaborative gaze convergence. Performance measures included the number of errors in tasks 1-7 and trainee's ratings in structured and standardized performance scores in task 8 (ex vivo porcine laparoscopic cholecystectomy). RESULTS: There was a significant improvement 1-7 on gaze latency [F(1,39) = 762.5, p < 0.01, ηp2 = 0.95], gaze convergence [F(1,39) = 482.8, p < 0.01, ηp2 = 0.93] and collaborative gaze convergence [F(1,39) = 408.4, p < 0.01, ηp2 = 0.91] upon instruction with iSurgeon. The number of errors was significantly lower in tasks 1-7 (0.18 ± 0.56 vs. 1.94 ± 1.80, p < 0.01) and the score ratings for laparoscopic cholecystectomy were significantly higher with telestration (global OSATS: 29 ± 2.5 vs. 25 ± 5.5, p < 0.01; task-specific OSATS: 60 ± 3 vs. 50 ± 6, p < 0.01). CONCLUSIONS: Telestration with augmented reality successfully improved surgical performance. The trainee's gaze behaviour was improved by reducing the time from instruction to fixation on targets and leading to a higher convergence of the instructor's and the trainee's gazes. Also, the convergence of trainee's gaze and target areas increased with telestration. This confirms augmented reality-based telestration works by means of gaze guidance in MIS and could be used to improve training outcomes.

Robotic-assisted versus laparoscopic bowel anastomoses: randomized crossover in vivo experimental study.

BACKGROUND: Initial learning curves are potentially shorter in robotic-assisted surgery (RAS) than in conventional laparoscopic surgery (LS). There is little evidence to support this claim. Furthermore, there is limited evidence how skills from LS transfer to RAS. METHODS: A randomized controlled, assessor blinded crossover study to compare how RAS naïve surgeons (n = 40) performed linear-stapled side-to-side bowel anastomoses in an in vivo porcine model with LS and RAS. Technique was rated using the validated anastomosis objective structured assessment of skills (A-OSATS) score and the conventional OSATS score. Skill transfer from LS to RAS was measured by comparing the RAS performance of LS novices and LS experienced surgeons. Mental and physical workload was measured with the NASA-task load index (NASA-Tlx) and the Borg-scale. OUTCOMES: In the overall cohort, there were no differences between RAS and LS for surgical performance (A-OSATS, time, OSATS). Surgeons that were naïve in both LS and RAS had significantly higher A-OSATS scores in RAS (Mean (Standard deviation (SD)): LS: 48.0 ± 12.1; RAS: 52.0 ± 7.5); p = 0.044) mainly deriving from better bowel positioning (LS: 8.7 ± 1.4; RAS: 9.3 ± 1.0; p = 0.045) and closure of enterotomy (LS: 12.8 ± 5.5; RAS: 15.6 ± 4.7; p = 0.010). There was no statistically significant difference in how LS novices and LS experienced surgeons performed in RAS [Mean (SD): novices: 48.9 ± 9.0; experienced surgeons: 55.9 ± 11.0; p = 0.540]. Mental and physical demand was significantly higher after LS. CONCLUSION: The initial performance was improved for RAS versus LS for linear stapled bowel anastomosis, whereas workload was higher for LS. There was limited transfer of skills from LS to RAS.

Clinical Relevance of Gastroesophageal Cancer Associated SNPs for Oncologic Outcome After Curative Surgery.

BACKGROUND: Gastric and esophageal cancers are malignant diseases with rising importance in Western countries. To improve oncologic outcome after surgery, it is essential to understand the relevance of germline mutations. The aim of the study was to identify and distinguish clinically relevant single-nucleotide polymorphisms (SNPs). PATIENTS AND METHODS: In total, 190 patients with curative oncological resections of gastric and distal esophageal adenocarcinomas at Heidelberg University Hospital were eligible for this study. Outcome differences were determined for each SNP by analysis of clinical variables, survival, and mRNA expression levels. RESULTS: Significant survival differences were found on univariate analysis for usual prognostic variables (such as pTNM) and for six SNPs. On multivariate survival analysis, the SNPs rs12268840 (intron variant of MGMT, p = 0.045) and rs9972882 (intron variant of STARD3 and eQTL of PGAP3, p = 0.030) were independent and significant survival predictors along with R status and pT/pN category. Group TT of rs12268840 had the highest rate of second primary carcinoma (30.4%, p = 0.0003), lowest expression of MGMT based on cis-eQTL analysis in normal gastroesophageal tissue (p = 1.99 × 10-17), and worst oncologic outcome. Group AA of rs9972882 had the highest rate of distant metastases pM1 (42.9%, p = 0.0117), highest expression of PGAP3 (p = 1.29 × 10-15), and worst oncologic outcome. CONCLUSIONS: Two intron variant SNPs of MGMT and STARD3 were identified that were significant survival predictors and may influence tumor biology. The data indicate that DNA methylation (MGMT) and malfunction of GPI anchoring (PGAP3) are distinct mechanisms that are relevant for tumor progression and relapse.

IMHOTEP: cross-professional evaluation of a three-dimensional virtual reality system for interactive surgical operation planning, tumor board discussion and immersive training for complex liver surgery in a head-mounted display.

BACKGROUND: Virtual reality (VR) with head-mounted displays (HMD) may improve medical training and patient care by improving display and integration of different types of information. The aim of this study was to evaluate among different healthcare professions the potential of an interactive and immersive VR environment for liver surgery that integrates all relevant patient data from different sources needed for planning and training of procedures. METHODS: 3D-models of the liver, other abdominal organs, vessels, and tumors of a sample patient with multiple hepatic masses were created. 3D-models, clinical patient data, and other imaging data were visualized in a dedicated VR environment with an HMD (IMHOTEP). Users could interact with the data using head movements and a computer mouse. Structures of interest could be selected and viewed individually or grouped. IMHOTEP was evaluated in the context of preoperative planning and training of liver surgery and for the potential of broader surgical application. A standardized questionnaire was voluntarily answered by four groups (students, nurses, resident and attending surgeons). RESULTS: In the evaluation by 158 participants (57 medical students, 35 resident surgeons, 13 attending surgeons and 53 nurses), 89.9% found the VR system agreeable to work with. Participants generally agreed that complex cases in particular could be assessed better (94.3%) and faster (84.8%) with VR than with traditional 2D display methods. The highest potential was seen in student training (87.3%), resident training (84.6%), and clinical routine use (80.3%). Least potential was seen in nursing training (54.8%). CONCLUSIONS: The present study demonstrates that using VR with HMD to integrate all available patient data for the preoperative planning of hepatic resections is a viable concept. VR with HMD promises great potential to improve medical training and operation planning and thereby to achieve improvement in patient care.

Surgomics: personalized prediction of morbidity, mortality and long-term outcome in surgery using machine learning on multimodal data.

BACKGROUND: Personalized medicine requires the integration and analysis of vast amounts of patient data to realize individualized care. With Surgomics, we aim to facilitate personalized therapy recommendations in surgery by integration of intraoperative surgical data and their analysis with machine learning methods to leverage the potential of this data in analogy to Radiomics and Genomics. METHODS: We defined Surgomics as the entirety of surgomic features that are process characteristics of a surgical procedure automatically derived from multimodal intraoperative data to quantify processes in the operating room. In a multidisciplinary team we discussed potential data sources like endoscopic videos, vital sign monitoring, medical devices and instruments and respective surgomic features. Subsequently, an online questionnaire was sent to experts from surgery and (computer) science at multiple centers for rating the features' clinical relevance and technical feasibility. RESULTS: In total, 52 surgomic features were identified and assigned to eight feature categories. Based on the expert survey (n = 66 participants) the feature category with the highest clinical relevance as rated by surgeons was "surgical skill and quality of performance" for morbidity and mortality (9.0 ± 1.3 on a numerical rating scale from 1 to 10) as well as for long-term (oncological) outcome (8.2 ± 1.8). The feature category with the highest feasibility to be automatically extracted as rated by (computer) scientists was "Instrument" (8.5 ± 1.7). Among the surgomic features ranked as most relevant in their respective category were "intraoperative adverse events", "action performed with instruments", "vital sign monitoring", and "difficulty of surgery". CONCLUSION: Surgomics is a promising concept for the analysis of intraoperative data. Surgomics may be used together with preoperative features from clinical data and Radiomics to predict postoperative morbidity, mortality and long-term outcome, as well as to provide tailored feedback for surgeons.

Evaluation of new motorized articulating laparoscopic instruments by laparoscopic novices using a standardized laparoscopic skills curriculum.

BACKGROUND: Motorized articulating laparoscopic instruments (ALI) offer more degrees of freedom than conventional laparoscopic instruments (CLI). However, a difficult learning curve and complex instrument handling are still a problem of ALI. We compared the performance of new prototypes of motorized ALI with CLI in a series of standardized laparoscopic tasks performed by laparoscopic novices. Further, usability of the new ALI was assessed. METHODS: A randomized cross-over study with 50 laparoscopic novices who either started with CLI and then changed to ALI (CA) or vice versa (AC) was conducted. All participants performed the European training in basic laparoscopic urological skills (E-BLUS) with each instrument in given order. Time and errors were measured for each exercise. Instrument usability was assessed. RESULTS: Overall, using CLI was significantly faster (CLI 4:27 min vs. ALI 4:50 min; p-value 0.005) and associated with fewer exercise failures in needle guidance (CLI 0 vs. ALI 12; p-value 0.0005) than ALI. Median amount of errors was similar for both instruments. Instrument sequence did not matter, as CA and AC showed comparable completion times. Regarding the learning effect, participants were significantly faster in the second attempt of exercises than in the first. In the needle guidance task, participants using CLI last demonstrated a significant speed improvement, whereas ALI were significantly slower in the second run. Regarding usability, CLI were preferred over ALI due to lighter weight and easier handling. Nevertheless, participants valued ALI's additional degrees of freedom. CONCLUSION: Using new motorized ALI in the E-BLUS examination by laparoscopic novices led to a worse performance compared to CLI. An explanation could be that participants felt overwhelmed by ALI and that ALI have an own distinct learning curve. As participants valued ALI's additional degrees of freedom, however, a future application of ALI could be for training purposes, ideally in combination with CLI.

Insufflation pressure above 25 mm Hg confers no additional benefit over lower pressure insufflation during posterior retroperitoneoscopic adrenalectomy: a retrospective multi-centre propensity score-matched analysis.

BACKGROUND: Insufflation pressures of or in excess of 25 mm Hg CO2 are routinely used during posterior retroperitoneoscopic adrenalectomy (PRA) in most centres. A critical analysis of the surgical literature provides limited evidence to support this strategy. OBJECTIVE: To determine whether high pressure (≥ 25 mm Hg) compared with lower pressure (< 25 mm Hg) retroperitoneoscopy reduces operating time and complications. METHODS: A multi-centre retrospective cohort study was performed using data collected over a period of almost one decade (1st November 2008 until 1st February 2018) from surgical centres in Germany. A total of 1032 patients with benign adrenal tumours were identified. We compared patients undergoing PRA with insufflation pressures of < 25 mm Hg (G20 group) versus ≥ 25 mm Hg (G25 group). A propensity score matching analysis was performed using BMI, tumour size and surgeon's experience as independent variables. The main outcomes were (1) the incidence of perioperative complications and (2) the length of operating time. RESULTS: The baseline patient characteristics were similar in both groups, with the exception of tumour size, BMI and surgeon's experience in PRA. After propensity score matching, perioperative outcomes, especially perioperative complications (3.7% vs. 5.5% in G20 and G25, respectively; p = 0.335) and operation duration (47 min vs. 45 min in G20 and G25, respectively; p = 0.673), did not significantly differ between the groups. CONCLUSION: Neither patient safety nor operative success was compromised when PRA was performed with insufflation pressures below 25 mm Hg. Prospective studies are required to determine whether an optimal insufflation pressure exists that maximizes patient safety and minimizes the risks of post-surgical complications. Nevertheless, our results call for a careful re-evaluation of the routine use of high insufflation pressures during PRA. In the absence of prospective data, commencing PRA with lower insufflation pressures, with the option of increasing insufflation pressures to counter intraoperative bleeding or exposition difficulties, may represent a reasonable strategy.

Laparoscopic Versus Open Pancreaticoduodenectomy: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

OBJECTIVE: To compare perioperative outcomes of laparoscopic pancreaticoduodenectomy (LPD) to open pancreaticoduodenectomy (OPD) using evidence from randomized controlled trials (RCTs). BACKGROUND: LPD is used more commonly, but this surge is mostly based on observational data. METHODS: We searched CENTRAL, Medline and Web of Science for RCTs comparing minimally invasive to OPD for adults with benign or malignant disease requiring elective pancreaticoduodenectomy. Main outcomes were 90-day mortality, Clavien-Dindo ≥3 complications, and length of hospital stay (LOS). Secondary outcomes were postoperative pancreatic fistula (POPF), delayed gastric emptying (DGE), postpancreatectomy hemorrhage (PPH), bile leak, blood loss, reoperation, readmission, oncologic outcomes (R0-resection, lymph nodes harvested), and operative times. Data were pooled as odds ratio (OR) or mean difference (MD) with a random-effects model. Risk of bias was assessed using the Cochrane Tool and the GRADE approach (Prospero registration ID: CRD42019120363). RESULTS: Three RCTs with a total of 224 patients were included. Meta-analysis showed there were no significant differences regarding 90-day mortality, Clavien-Dindo ≥3 complications, LOS, POPF, DGE, PPH, bile leak, reoperation, readmission, or oncologic outcomes between LPD and OPD. Operative times were significantly longer for LPD {MD [95% confidence interval (CI)] 95.44 minutes (24.06-166.81 minutes)}, whereas blood loss was lower for LPD [MD (CI) -150.99 mL (-168.54 to -133.44 mL)]. Certainty of evidence was moderate to very low. CONCLUSIONS: At current level of evidence, LPD shows no advantage over OPD. Limitations include high risk of bias and moderate to very low certainty of evidence. Further studies should focus on patient safety during LPD learning curves and the potential role of robotic surgery.

Obesity and the Lung: What We Know Today.

Obesity is becoming more and more prevalent especially in Western industrial nations. The understanding of adipose tissue as an endocrine organ as well as the detection of adipocytokines - hormones that are secreted from the adipose tissue - gave reason to examine the interactions between adipose tissue and target organs. These efforts have been intensified especially in the context of bariatric surgery as promising weight loss therapy. Interactions between the lung and adipose tissue have rarely been investigated and are not well understood. There are obvious mechanical effects of obesity on lung function explaining the associations between obesity and lung diseases, in particular obesity hypoventilation syndrome, obstructive sleep apnea syndrome, asthma, and chronic obstructive pulmonary disease. The rise in the prevalence of obesity affects the epidemiology of pulmonary diseases as well. The aim of this review is to summarize the current knowledge on interactions, associations, and consequences of obesity and weight loss on lung function and lung diseases. Based on these data, areas for future research are identified.

Correction to: Development and validation of an objective assessment scale for chest tube insertion under 'direct' and 'indirect' rating.

Following publication of the original article [1], the author reported that the given name and family name of all authors were swapped.

Impact of visual-spatial ability on laparoscopic camera navigation training.

BACKGROUND: Technical limitations of minimally invasive surgery challenge both surgeons and camera assistants. Current research indicates that visual-spatial ability (VSA) has impact on learning of laparoscopic camera navigation (LCN). However, it remains unclear if complexity of LCN tasks influences the impact of VSA. The aim of this study was to examine the influence of VSA on LCN training within tasks of different complexity levels. METHODS: The present study was conducted as a monocentric prospective trial. VSA was assessed with a cube comparison test before participants underwent LCN training. LCN training consisted of three tasks with increasing complexity. Each task was performed four times and performance was assessed each time. Correlations and multivariate regression analysis were used to assess the influence of VSA on LCN skills. RESULTS: Seventy-one participants were included (35 males). Significant performance improvement and faster completion times were observed from the first to fourth trial of all three LCN training tasks. Significant positive correlations between VSA and performance on LCN task 3 were found (performance: r s = 0.47; p < 0.001, time: r s = -0.43; p < 0.001). Multivariate regression revealed that higher VSA resulted in greater reduction of time between the first trials of LCN training task 3 (B = -1.67, p = 0.031). CONCLUSION: In the present study, all trainees improved LCN performance during the training. VSA seems to have impact on LCN performance and training progress particularly for complex LCN tasks. The relation of VSA and LCN performance was stronger for less experienced participants and in the beginning of the learning phase.

Mobile, real-time, and point-of-care augmented reality is robust, accurate, and feasible: a prospective pilot study.

BACKGROUND: Augmented reality (AR) systems are currently being explored by a broad spectrum of industries, mainly for improving point-of-care access to data and images. Especially in surgery and especially for timely decisions in emergency cases, a fast and comprehensive access to images at the patient bedside is mandatory. Currently, imaging data are accessed at a distance from the patient both in time and space, i.e., at a specific workstation. Mobile technology and 3-dimensional (3D) visualization of radiological imaging data promise to overcome these restrictions by making bedside AR feasible. METHODS: In this project, AR was realized in a surgical setting by fusing a 3D-representation of structures of interest with live camera images on a tablet computer using marker-based registration. The intent of this study was to focus on a thorough evaluation of AR. Feasibility, robustness, and accuracy were thus evaluated consecutively in a phantom model and a porcine model. Additionally feasibility was evaluated in one male volunteer. RESULTS: In the phantom model (n = 10), AR visualization was feasible in 84% of the visualization space with high accuracy (mean reprojection error ± standard deviation (SD): 2.8 ± 2.7 mm; 95th percentile = 6.7 mm). In a porcine model (n = 5), AR visualization was feasible in 79% with high accuracy (mean reprojection error ± SD: 3.5 ± 3.0 mm; 95th percentile = 9.5 mm). Furthermore, AR was successfully used and proved feasible within a male volunteer. CONCLUSIONS: Mobile, real-time, and point-of-care AR for clinical purposes proved feasible, robust, and accurate in the phantom, animal, and single-trial human model shown in this study. Consequently, AR following similar implementation proved robust and accurate enough to be evaluated in clinical trials assessing accuracy, robustness in clinical reality, as well as integration into the clinical workflow. If these further studies prove successful, AR might revolutionize data access at patient bedside.

Evaluation of App-Based Serious Gaming as a Training Method in Teaching Chest Tube Insertion to Medical Students: Randomized Controlled Trial.

BACKGROUND: The insertion of a chest tube should be as quick and accurate as possible to maximize the benefit and minimize possible complications for the patient. Therefore, comprehensive training and assessment before an emergency situation are essential for proficiency in chest tube insertion. Serious games have become more prevalent in surgical training because they enable students to study and train a procedure independently, and errors made have no effect on patients. However, up-to-date evidence regarding the effect of serious games on performance in procedures in emergency medicine remains scarce. OBJECTIVE: The aim of this study was to investigate the serious gaming approach in teaching medical students an emergency procedure (chest tube insertion) using the app Touch Surgery and a modified objective structural assessment of technical skills (OSATS). METHODS: In a prospective, rater-blinded, randomized controlled trial, medical students were randomized into two groups: intervention group or control group. Touch Surgery has been established as an innovative and cost-free app for mobile devices. The fully automatic software enables users to train medical procedures and afterwards self-assess their training effort. The module chest tube insertion teaches each key step in the insertion of a chest tube and enables users the meticulous application of a chest tube. In contrast, the module "Thoracocentesis" discusses a basic thoracocentesis. All students attended a lecture regarding chest tube insertion (regular curriculum) and afterwards received a Touch Surgery training lesson: intervention group used the module chest tube insertion and the control group used Thoracocentesis as control training. Participants' performance in chest tube insertion on a porcine model was rated on-site via blinded face-to-face rating and via video recordings using a modified OSATS tool. Afterwards, every participant received an individual questionnaire for self-evaluation. Here, trainees gave information about their individual training level, as well as previous experiences, gender, and hobbies. Primary end point was operative performance during chest tube insertion by direct observance. RESULTS: A total of 183 students enrolled, 116 students participated (63.4%), and 21 were excluded because of previous experiences in chest tube insertion. Students were randomized to the intervention group (49/95, 52%) and control group (46/95, 48%). The intervention group performed significantly better than the control group (Intervention group: 38.0 [I50=7.0] points; control group: 30.5 [I50=8.0] points; P<.001). The intervention group showed significantly improved economy of time and motion (P=.004), needed significantly less help (P<.001), and was more confident in handling of instruments (P<.001) than the control group. CONCLUSIONS: The results from this study show that serious games are a valid and effective tool in education of operative performance in chest tube insertion. We believe that serious games should be implemented in the surgical curriculum, as well as residency programs, in addition to traditional learning methods. TRIAL REGISTRATION: German Clinical Trials Register (DRKS) DRKS00009994; https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00009994 (Archived by Webcite at http://www.webcitation.org/6ytWF1CWg).

Development and validation of an objective assessment scale for chest tube insertion under 'direct' and 'indirect' rating.

BACKGROUND: There is an increasing need for objective and validated educational concepts. This holds especially true for surgical procedures like chest tube insertion (CTI). Thus, we developed an instrument for objectification of learning successes: the assessment scale based on Objective Structured Assessment of Technical Skill (OSATS) for chest tube insertion, which is evaluated in this study. Primary endpoint was the evaluation of intermethod reliability (IM). Secondary endpoints are 'indirect' interrater reliability (IR) and construct validity of the scale (CV). METHODS: Every participant (N = 59) performed a CTI on a porcine thorax. Participants received three ratings (one 'direct' on site, two 'indirect' via video rating). IM compares 'direct' with 'indirect' ratings. IR was assessed between 'indirect' ratings. CV was investigated by subgroup analysis based on prior experience in CTI for 'direct' and 'indirect' rating. RESULTS: We included 59 medical students to our study. IM showed moderate conformity ('direct' vs. 'indirect 1' ICC = 0.735, 95% CI: 0.554-0.843; 'direct' vs. 'indirect 2' ICC = 0.722, 95% CI 0.533-0.835) and good conformity between 'direct' vs. 'average indirect' rating (ICC = 0.764, 95% CI: 0.6-0.86). IR showed good conformity (ICC = 0.84, 95% CI: 0.707-0.91). CV was proven between subgroups in 'direct' (p = 0.037) and 'indirect' rating (p = 0.013). CONCLUSION: Results for IM suggest equivalence for 'direct' and 'indirect' ratings, while both IR and CV was demonstrated in both rating methods. Thus, the assessment scale seems a reliable method for rating trainees' performances 'directly' as well as 'indirectly'. It may help to objectify and facilitate the assessment of training of chest tube insertion.

Face validity of the pulsatile organ perfusion trainer for laparoscopic cholecystectomy.

BACKGROUND: The pulsatile organ perfusion (POP) trainer provides training of minimally invasive surgery (MIS) with real instruments and cadaveric organs. It provides training of full procedures with simulation of bleeding. Although widely used, the face validity has not yet been evaluated. This study aimed to establish face validity of the POP trainer for laparoscopic cholecystectomy (LC) and its usefulness compared with other training modalities. MATERIALS AND METHODS: During MIS courses, the participants (n = 52) used the POP trainer to perform LC. Face validity was assessed with questionnaires for realism and usefulness on a five-point Likert scale. Participants were divided into two groups: experts (n = 15) who had performed more than 50 laparoscopic procedures and novices (n = 37) with less than 50 procedures. Secondary aims included the ranking of training modalities, as well as exploration of their specific advantages and disadvantages. RESULTS: The POP trainer was found to be realistic (3.8 ± 0.9) and useful (4.6 ± 0.9). Differences between experts and novices were only found for "The training modality resembles reality" (3.1 ± 0.8 vs. 3.8 ± 0.7; p = 0.010), "The operation on the POP trainer is realistic" (3.4 ± 1.1 vs. 4.5 ± 0.8; p = 0.003), and "It would be desirable to have a POP trainer at my own hospital" (4.2 ± 1.1 vs. 4.8 ± 0.8; p = 0.040). In the ranking, the animal training (1.1 ± 0.3) placed first, the POP trainer (2.3 ± 0.9) second, and the VR trainer (2.8 ± 0.9) and box trainer (2.8 ± 1.1) third. The realistic simulation of animal training was named as an advantage most often, while the unrealistic simulation of the VR trainer was the most often named disadvantage. CONCLUSIONS: The POP trainer was rated a highly realistic and useful training modality with face validity for LC. Differences between experts and novices existed concerning realism and desirability. Future studies should evaluate the POP trainer for more advanced surgical procedures. The POP trainer widens the spectrum of modalities for training of MIS in a safe environment outside the operating room.

[New Approaches for Young Surgeons - Students' Symposium on Minimally Invasive Surgery]. / Neue Wege zum chirurgischen Nachwuchs ­ Studierendenforum für Minimal Invasive Chirurgie.

Background Physician shortage is particularly striking in surgical specialities. Umbrella organisations are making an effort to recruit medical students. Students' symposia during congresses seem to provide a promising approach to developing motivation and promoting interest. An exemplary students' symposium took place at the three nations meeting for minimally invasive surgery (MIS). Our aim was to evaluate the students' symposium from the students' perspective, in order to give recommendations for the future. Methods Of a total of 60 participants, half (30/60) completed the survey. Using a 5-point Likert scale, students evaluated items on the agenda, increase in interests, personal benefit and likelihood of future participation. Results Sixty percent (18/30) of the participants in the student forum reported enhanced interest in MIC - the largest increase found. For surgery in general and for robotic surgery in particular, an increase was reported by 57% (17/30) of the students. Of all the items on the agenda, laparoscopic hands-on experience was rated best - with a positive rating from 90% (27/30) of the students. Students expressed the wish for improved personal exchange with experts and professionals. Two thirds (40/60) of the students stated that future participation was definite or very likely. Discussion The increase in interest in MIS and surgery in general demonstrated the success of the students' symposium. Hands-on experiences was very popular. Future events should focus on personal exchange between students and experts. This seems necessary to reduce prejudice in the debate on a well-adjusted work-life balance. With a view to physician shortage in surgical specialties, students' symposia are a valuable option that should be firmly established and consistently developed.

Navigation system for minimally invasive esophagectomy: experimental study in a porcine model.

BACKGROUND: Navigation systems potentially facilitate minimally invasive esophagectomy and improve patient outcome by improving intraoperative orientation, position estimation of instruments, and identification of lymph nodes and resection margins. The authors' self-developed navigation system is highly accurate in static environments. This study aimed to test the overall accuracy of the navigation system in a realistic operating room scenario and to identify the different sources of error altering accuracy. METHODS: To simulate a realistic environment, a porcine model (n = 5) was used with endoscopic clips in the esophagus as navigation targets. Computed tomography imaging was followed by image segmentation and target definition with the medical imaging interaction toolkit software. Optical tracking was used for registration and localization of animals and navigation instruments. Intraoperatively, the instrument was displayed relative to segmented organs in real time. The target registration error (TRE) of the navigation system was defined as the distance between the target and the navigation instrument tip. The TRE was measured on skin targets with the animal in the 0° supine and 25° anti-Trendelenburg position and on the esophagus during laparoscopic transhiatal preparation. RESULTS: On skin targets, the TRE was significantly higher in the 25° position, at 14.6 ± 2.7 mm, compared with the 0° position, at 3.2 ± 1.3 mm. The TRE on the esophagus was 11.2 ± 2.4 mm. The main source of error was soft tissue deformation caused by intraoperative positioning, pneumoperitoneum, surgical manipulation, and tissue dissection. CONCLUSION: The navigation system obtained acceptable accuracy with a minimally invasive transhiatal approach to the esophagus in a realistic experimental model. Thus the system has the potential to improve intraoperative orientation, identification of lymph nodes and adequate resection margins, and visualization of risk structures. Compensation methods for soft tissue deformation may lead to an even more accurate navigation system in the future.