Laura Benner

Impact of visual–spatial ability on laparoscopic camera navigation training

BackgroundTechnical 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.MethodsThe 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.ResultsSeventy-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: rsxa0=xa00.47; pxa0<xa00.001, time: rsxa0=xa0−0.43; pxa0<xa00.001). Multivariate regression revealed that higher VSA resulted in greater reduction of time between the first trials of LCN training task 3 (Bxa0=xa0−1.67, pxa0=xa00.031).ConclusionIn 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.

Bariatric Surgery as an Efficient Treatment for Non-Alcoholic Fatty Liver Disease in a Prospective Study with 1-Year Follow-up: BariScan Study

BackgroundBariatric surgery gains attention as a potential treatment for non-alcoholic fatty liver disease (NAFLD). The present study aimed to evaluate improvement of NAFLD after the two most common bariatric procedures with validated non-invasive instruments.Material and MethodsNxa0=xa0100 patients scheduled for laparoscopic sleeve gastrectomy (LSG) or Roux-en-Y gastric bypass (RYGB) were included. NAFLD was evaluated preoperatively and postoperatively with liver stiffness measurement by transient elastography and laboratory-based fibrosis scores. Clinical data included body mass index (BMI), total weight loss (%TWL), excess weight loss (%EWL), age, gender, comorbidities, and the Edmonton obesity staging system (EOSS).ResultsThere were significant improvements of BMI, %TWL, %EWL, and EOSS after bariatric surgery. Liver stiffness was significantly improved from pre- to postoperative (12.9xa0±xa010.4 vs. 7.1xa0±xa03.7xa0kPa, pxa0<xa00.001) at median follow-up of 12.5xa0months. Additionally, there were significant improvements of liver fibrosis scores (aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio 0.8xa0±xa00.3 vs. 1.1xa0±xa00.4, pxa0<xa00.001; NAFLD fibrosis score −xa01.0xa0±xa01.8 vs. −xa01.7xa0±xa01.3, pxa0<xa00.001; APRI score 0.3xa0±xa00.2 vs. 0.3xa0±xa00.1, pxa0=xa00.009; BARD score 2.3xa0±xa01.2 vs. 2.8xa0±xa01.1, pxa0=xa00.008) and laboratory parameters (ALT, AST, and GGT). After adjustment for baseline liver stiffness, RYGB showed higher improvements than LSG, and there was no gender difference. Improvement of liver stiffness was not correlated to improvement of BMI, %TWL, %EWL, or EOSS.ConclusionsNAFLD seems to be improved by bariatric surgery as measured by validated non-invasive instruments. Furthermore, it appears that RYGB is more effective than LSG. No correlation could be detected between NAFLD and weight loss. The present study highlights the potential of bariatric surgery for successful treatment of NAFLD. Further research is required to understand the exact mechanisms.

Point estimation in adaptive enrichment designs

Adaptive enrichment designs are an attractive option for clinical trials that aim at demonstrating efficacy of therapies, which may show different benefit for the full patient population and a prespecified subgroup. In these designs, based on interim data, either the subgroup or the full population is selected for further exploration. When selection is based on efficacy data, this introduces bias to the commonly used maximum likelihood estimator. For the situation of two-stage designs with a single prespecified subgroup, we present six alternative estimators and investigate their performance in a simulation study. The most consistent reduction of bias over the range of scenarios considered was achieved by a method combining the uniformly minimum variance conditionally unbiased estimator with a conditional moment estimator. Application of the methods is illustrated by a clinical trial example.

Grundlagen für den Umgang mit Daten

In diesem Kapitel soll anhand der Daten, die fur die nachfolgenden Auswertungen herangezogen werden, das Vorgehen beim Importieren von Exceldaten in SPSS erlautert und auf die Bearbeitung bzw. Berechnung neuer Variablen eingegangen werden.

Statistische Tests und Grafiken

Der primare Endpunkt in einer klinischen Studie ist jenes Zielkriterium bzw. Outcome, anhand dessen der Erfolg der Studie (z.B. Nachweis der Wirksamkeit einer neuen Therapie) beurteilt wird. Zur Analyse des primaren Endpunkts stehen zum einen deskriptive, zum anderen konfirmatorische Methoden zur Verfugung. Mittels konfirmatorischer Methoden sollen Ruckschlusse auf die interessierende Grundgesamtheit gezogen und die Studienergebnisse somit verallgemeinert werden.

Hand-Assisted laparoscopic donor nephrectomy PERiumbilical versus Pfannenstiel incision and return to normal physical ACTivity (HAPERPACT): study protocol for a randomized controlled trial

BackgroundHand-assisted laparoscopic living donor nephrectomy (HALDN) using a periumbilical or Pfannenstiel incision was developed to improve donor outcome after a kidney transplant. The aim of this study was to investigate two methods of hand assistance and kidney removal during HALDN and their effect on the time it takes for the donor to return to normal physical activity.Methods/designThis study was initiated in November 2017 and is expected to last for 2 years. To be eligible for the study, donors must be more than 20xa0years of age and must not be receiving permanent pain therapy. Only donors with a single artery and vein in the graft are being enrolled in this trial. Donors with infections or scars in the periumbilical or hypogastric area, bleeding disorders, chronic use of immunosuppressive agents, or active infection will be excluded. Donors will be randomly allocated to either a control arm (periumbilical incision) or an intervention arm (Pfannenstiel incision). The sample size was calculated as 26 organ donors in each group. The primary endpoint is the number of days it takes the donor to return to normal physical activity (up to 4 weeks after the operation). Secondary endpoints are intraoperative outcomes, including estimated blood loss, warm ischemia time, and duration of the operation. Postoperative pain will be assessed using the visual analog scale, rescue analgesic use, and peak expiratory flow rate. Length of hospital stay, physical activity score, time to return to work, donor satisfaction, cosmetic score, postoperative complications, and all-cause mortality in living donors will also be reported. Delayed graft function, primary non-function, serum creatinine levels, and glomerular filtration rate will also be assessed in the recipients after transplantation.DiscussionThis is the first randomized controlled trial to compare the time it takes the living donor to return to normal physical activity after HALDN using two different types of incision. The comprehensive findings of this study will help decide which nephrectomy procedure is best for living donors with regard to patient comfort and satisfaction as well as graft function in the recipient after transplantation.Trial registrationClinicalTrials.gov, NCT03317184. Registered on 23 October 2017.

The Heidelberg VR Score: development and validation of a composite score for laparoscopic virtual reality training

IntroductionVirtual reality (VR-)trainers are well integrated in laparoscopic surgical training. However, objective feedback is often provided in the form of single parameters, e.g., time or number of movements, making comparisons and evaluation of trainees’ overall performance difficult. Therefore, a new standard for reporting outcome data is highly needed. The aim of this study was to create a weighted, expert-based composite score, to offer simple and direct evaluation of laparoscopic performance on common VR-trainers.Materials and methodsAn integrated analytic hierarchy process-Delphi survey was conducted with 14 international experts to achieve a consensus on the importance of different skill categories and parameters in evaluation of laparoscopic performance. A scoring algorithm was established to allow comparability between tasks and VR-trainers. A weighted composite score was calculated for basic skills tasks and peg transfer on the LapMentor™ II and III and validated for both VR-trainers.ResultsFive major skill categories (time, efficiency, safety, dexterity, and outcome) were identified and weighted in two Delphi rounds. Safety, with a weight of 67%, was determined the most important category, followed by efficiency with 17%. The LapMentor™-specific score was validated using 15 (14) novices and 9 experts; the score was able to differentiate between both groups for basic skills tasks and peg transfer (LapMentor™ II: Exp: 86.5u2009±u200912.7, Nov. 52.8u2009±u200918.3; pu2009<u20090.001; LapMentor™ III: Exp: 80.8u2009±u20097.1, Nov: 50.6u2009±u200916.9; pu2009<u20090.001).ConclusionAn effective and simple performance measurement was established to propose a new standard in analyzing and reporting VR outcome data—the Heidelberg virtual reality (VR) score. The scoring algorithm and the consensus results on the importance of different skill aspects in laparoscopic surgery are universally applicable and can be transferred to any simulator or task. By incorporating specific expert baseline data for the respective task, comparability between tasks, studies, and simulators can be achieved.

One or two trainees per workplace for laparoscopic surgery training courses: results from a randomized controlled trial

BackgroundThere are no standards for optimal utilization of workplaces in laparoscopic training. This study aimed to define whether laparoscopy training should be done alone or in pairs (known as dyad training).MethodsThis was a three-arm randomized controlled trial with laparoscopically naïve medical students (nu2009=u2009100). Intervention groups participated alone (nu2009=u200940) or as dyad (nu2009=u200940) in a multimodality training curriculum with e-learning, basic, and procedural skills training using box and VR trainers. The control group (nu2009=u200920) had no training. Post-performance of a cadaveric porcine laparoscopic cholecystectomy (LC) was measured as the primary outcome by blinded raters using the objective structured assessment of technical skills (OSATS). Global operative assessment of laparoscopic skills (GOALS), time for LC, and VR performances were secondary outcomes.ResultsThere were no differences between groups for performance scores [OSATS: alone (40.2u2009±u20099.8) vs. dyad (39.8u2009±u20098.6), pu2009=u20090.995; alone vs. control (37.1u2009±u20097.4), pu2009=u20090.548; or dyad vs. control, pu2009=u20090.590; and GOALS score: alone (10.6u2009±u20093.0) vs. dyad (10.0u2009±u20092.7), pu2009=u20090.599; alone vs. control (10.1u2009±u20093.0), pu2009=u20090.748; or dyad vs. control, pu2009=u20090.998]. Dyad finished LC faster than control [medianu2009=u200962.5xa0min (CI 58.0–73.0) vs. 76.5xa0min (CI 72.0–80+); pu2009=u20090.042], while there were no inter-group differences between alone vs. control [medianu2009=u200969.0xa0min (CI 62.0–76.0) vs. control; pu2009=u20090.099] or alone vs. dyad (pu2009=u20090.840). Dyad and alone showed superior performance on the VR trainer vs. control for time, number of movements, and path length, but not for complications and application of cautery.ConclusionsThe curriculum provided trainees with the laparoscopic skills needed to perform LC safely, irrespective of the number of trainees per workplace. Dyad training reduced the operation time needed for LC. Therefore, dyad training seems to be a promising alternative, especially if training time is limited and resources must be used as efficiently as possible. Trial registration German Clinical Trials Register: DRKS00004675.

Does rating with a checklist improve the effect of E-learning for cognitive and practical skills in bariatric surgery? A rater-blinded, randomized-controlled trial

BackgroundMental training of laparoscopic procedures with E-learning has been shown to translate to the operating room. The present study aims to explore whether the use of checklists during E-learning improves transfer of skills to the simulated OR on a Virtual Reality (VR) trainer for Roux-en-Y gastric bypass (RYGB).MethodsLaparoscopy naive medical students (nu2009=u200980) were randomized in two groups. After an E-learning introduction to RYGB, checklist group rated RYGB videos using the validated Bariatric Objective Structured Assessment of Technical Skills (BOSATS) checklist while group without checklist only observed the videos. Participants then performed RYGB on a VR-trainer twice and were evaluated by a blinded expert rater using BOSATS. A multiple choice (MC) knowledge test on RYGB was performed. Suturing on a cadaveric porcine small bowel was evaluated using objective structured assessment of technical skill (OSATS).ResultsChecklist group was better in the knowledge test (A 8.3u2009±u20091.1 vs. B 7.1u2009±u20091.3; pu2009≤u20090.001) and there was a trend towards better VR RYGB performance (BOSATS) on the first try (85.9u2009±u200910.2 vs. 81.1u2009±u200911.5; pu2009=u20090.058), but not on the second try (92.0u2009±u20099.7 vs. 89.3u2009±u200910.5; pu2009=u20090.251). Suturing as measured by OSATS was not different (29.5u2009±u20093.0 vs. 29.0u2009±u20093.5; pu2009=u20090.472).ConclusionThis study presents evidence that the use of a BOSATS checklist during E-learning helps trainees to improve their knowledge acquisition with E-learning. The transfer from mental training to the simulated OR environment seems to be partially enhanced by use of the BOSATS checklist. However, more research is required to investigate potential benefits.

Contamination After Disinfectant Rectal Washout in Left Colectomy as a Model for Transrectal NOTES: A Randomized Controlled Trial

BACKGROUNDnIn natural orifice transluminal endoscopic surgery (NOTES) with transrectal (TR) access the intraoperative opening of the rectal wall poses a risk of intraperitoneal contamination and subsequent infectious complications. A rectal washout with a disinfectant may reduce this risk. The aim of the study was to assess the intraoperative contamination on the circular stapler pin when a rectal washout with povidone-iodine (RW-PI) or Ringer solution was performed in patients undergoing left-sided colectomy. Furthermore, the additional effect of an irrigation instrument on the contamination was evaluated.nnnMETHODSnIn a patient and assessor blinded randomized controlled trial, patients undergoing left-sided colectomy were assigned to rectal washout with PI with an irrigation instrument (RW-PI; nxa0=xa023), rectal washout with Ringer solution with an irrigation instrument (RW-R; nxa0=xa021) or rectal washout with Ringer solution without an irrigation instrument (RW; nxa0=xa025). An end-to-end anastomosis with a circular stapler was performed. The contamination on the pin of the circular stapler was chosen as primary endpoint in order to simulate the intraabdominal contamination risk during TR NOTES. Secondary endpoints were contamination of the rectal mucosa, peritoneal contamination and postoperative morbidity.nnnRESULTSnThe contamination rate of the pin of the circular stapler did not differ (RW-PI 39.1%, RW-R 33.3%, RW 52.0%; Pxa0=xa00.421), but contamination of the rectal mucosa was reduced (47.8% versus 95.2% versus 100%; Pxa0<xa00.001) and peritoneal contamination tended to be reduced (39.1% versus 71.4% versus 60.0%; Pxa0=xa00.09) when a rectal washout with PI was performed. The rates of infectious complications (17.4% versus 9.5% versus 12.0%; Pxa0=xa00.821) and of overall complications (30.4% versus 28.6% versus 44.0%; Pxa0=xa00.476) did not differ.nnnCONCLUSIONSnDespite an intense rectal washout with PI, contamination of the stapler pin did not differ. Intraabdominal bacterial translocation was frequently encountered even after disinfectant rectal washout with PI. Further studies might focus on the clinical impact of intraabdominal contamination in TR NOTES.