Felix Nickel
Heidelberg University
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Featured researches published by Felix Nickel.
Langenbeck's Archives of Surgery | 2012
Hannes Kenngott; Lars Fischer; Felix Nickel; J. Rom; J. Rassweiler; B. P. Müller-Stich
PurposeRobotic assistance is considered one innovation within abdominal surgery over the past decade that has the potential to compensate for the drawbacks of conventional laparoscopy, such as limited degree of freedom, 2D vision, fulcrum, and pivoting effect. Robotic systems provide corresponding solutions as 3D view, intuitive motion and enable additional degrees of freedom. This review provides an overview of the history of medical robotics, experimental studies, clinical state-of-the-art and economic impact.MethodsThe Medline database was searched for the terms “robot*, telemanipulat*, and laparoscop*.” A total of 2573 references were found. All references were considered for information on robotic assistance in advanced laparoscopy. Further references were obtained through cross-referencing the bibliography cited in each work.ResultsIn experimental studies, current robotic systems showed superior handling and ergonomics compared to conventional laparoscopic techniques. In gynecology especially for hysterectomy and in urology especially for prostatectomy, two procedures formerly performed via an open approach, the robot enables a laparoscopic approach. This results in reduced need for pain medication, less blood loss, and shorter hospital stay. Within abdominal surgery, clinical studies were generally unable to prove a benefit of the robot. While the benefit still remains open to discussion, robotic systems are spreading and are available worldwide in tertiary centers.ConclusionRobotic assistance will remain an intensively discussed subject since clinical benefits for most procedures have not yet been proven. The most promising procedures are those in which the robot enables a laparoscopic approach where open surgery is usually required.
Medicine | 2015
Felix Nickel; Julia A. Brzoska; Matthias Gondan; Henriette M. Rangnick; Jackson Chu; Hannes Kenngott; Georg R. Linke; Martina Kadmon; Lars Fischer; Beat P. Müller-Stich
AbstractThis study compared virtual reality (VR) training with low cost-blended learning (BL) in a structured training program.Training of laparoscopic skills outside the operating room is mandatory to reduce operative times and risks.Laparoscopy-naïve medical students were randomized in 2 groups stratified for sex. The BL group (n = 42) used E-learning for laparoscopic cholecystectomy (LC) and practiced basic skills with box trainers. The VR group (n = 42) trained basic skills and LC on the LAP Mentor II (Simbionix, Cleveland, OH). Each group trained 3 × 4 hours followed by a knowledge test concerning LC. Blinded raters assessed the operative performance of cadaveric porcine LC using the Objective Structured Assessment of Technical Skills (OSATS). The LC was discontinued when it was not completed within 80 min. Students evaluated their training modality with questionnaires.The VR group completed the LC significantly faster and more often within 80 min than BL (45% v 21%, P = .02). The BL group scored higher than the VR group in the knowledge test (13.3 ± 1.3 vs 11.0 ± 1.7, P < 0.001). Both groups showed equal operative performance of LC in the OSATS score (49.4 ± 10.5 vs 49.7 ± 12.0, P = 0.90). Students generally liked training and felt well prepared for assisting in laparoscopic surgery. The efficiency of the training was judged higher by the VR group than by the BL group.VR and BL can both be applied for training the basics of LC. Multimodality training programs should be developed that combine the advantages of both approaches.
Annals of Surgery | 2013
Beat P. Müller-Stich; Lars Fischer; Hannes Kenngott; Matthias Gondan; Jonas Senft; Gabriella Clemens; Felix Nickel; Thomas Fleming; Peter P. Nawroth; Markus W. Büchler
Objective:Surprisingly, 40% to 95% of patients with type 2 diabetes mellitus (T2DM) show early remission of hyperglycemia after obesity surgery. It is unknown to what extent other diabetes-associated comorbidities such as distal peripheral neuropathy (DPN) might be influenced by obesity surgery. This pilot study aimed at providing further evidence for the impact of Roux-en-Y gastric bypass (RYGB) on both glycemic control and DPN in nonseverely obese patients with insulin-dependent T2DM. Methods:In the present prospective cohort study, 20 patients with long-standing, insulin-dependent T2DM and a body mass index (BMI) between 25 and 35 kg/m2 underwent laparoscopic RYGB. Body mass index, glycosylated hemoglobin (HbA1c), and DPN [quantified by the Neuropathy Symptom Score (NSS) and the Neuropathy Deficit Score (NDS)] were investigated. Results:Six months after surgery, the preoperative BMI of 32.8 ± 2.1 kg/m2 (mean ± standard deviation) dropped to 25.6 ± 2.5 kg/m2 (P < 0.001). Preoperative HbA1c levels decreased from 8.5 ± 1.2% to 7.1 ± 1.2% (P < 0.001), with 15% of patients having a normalized HbA1c level lower than 6.2%. Of 12 patients with documented DPN, the median NSS was 8 (range, 0–10) preoperatively and 0 (range, 0–9) postoperatively (P = 0.004), with 8 patients scoring an NSS of 0. The median NDS was 6 (range, 2–8) preoperatively and 4 (range, 0–8) postoperatively (P = 0.027), with 1 patient scoring an NDS of 0. All patients had an improvement or normalization in either 1 or both scores. Conclusions:As expected, BMI and HbA1c levels improved significantly after RYGB. More interestingly, neuropathy scores, such as NSS and NDS, improved significantly early after surgery. Symptomatic neuropathy was completely reversible in 67% of the patients. These findings add further evidence to the fact that RYGB might be a valuable treatment option not only for improving glycemic control but also for reducing diabetes-associated comorbidities, such as DPN. This points to a complex metabolic effect of RYGB that exceeds glucose normalization. However, the results still need to be confirmed in controlled trials.
PLOS ONE | 2015
Beat P. Müller-Stich; Hannes Kenngott; Matthias Gondan; Christian Stock; Georg R. Linke; Franziska Fritz; Felix Nickel; Markus K. Diener; Carsten N. Gutt; Moritz N. Wente; Markus W. Büchler; Lars Fischer
Introduction Mesh augmentation seems to reduce recurrences following laparoscopic paraesophageal hernia repair (LPHR). However, there is an uncertain risk of mesh-associated complications. Risk-benefit analysis might solve the dilemma. Materials and Methods A systematic literature search was performed to identify randomized controlled trials (RCTs) and observational clinical studies (OCSs) comparing laparoscopic mesh-augmented hiatoplasty (LMAH) with laparoscopic mesh-free hiatoplasty (LH) with regard to recurrences and complications. Random effects meta-analyses were performed to determine potential benefits of LMAH. All data regarding LMAH were used to estimate risk of mesh-associated complications. Risk-benefit analysis was performed using a Markov Monte Carlo decision-analytic model. Results Meta-analysis of 3 RCTs and 9 OCSs including 915 patients revealed a significantly lower recurrence rate for LMAH compared to LH (pooled proportions, 12.1% vs. 20.5%; odds ratio (OR), 0.55; 95% confidence interval (CI), 0.34 to 0.89; p = 0.04). Complication rates were comparable in both groups (pooled proportions, 15.3% vs. 14.2%; OR, 1.02; 95% CI, 0.63 to 1.65; p = 0.94). The systematic review of LMAH data yielded a mesh-associated complication rate of 1.9% (41/2121; 95% CI, 1.3% to 2.5%) for those series reporting at least one mesh-associated complication. The Markov Monte Carlo decision-analytic model revealed a procedure-related mortality rate of 1.6% for LMAH and 1.8% for LH. Conclusions Mesh application should be considered for LPHR because it reduces recurrences at least in the mid-term. Overall procedure-related complications and mortality seem to not be increased despite of potential mesh-associated complications.
Trials | 2014
Felix Nickel; Felix Jede; Andreas Minassian; Matthias Gondan; Jonathan D. Hendrie; Tobias Gehrig; Georg R. Linke; Martina Kadmon; Lars Fischer; Beat P. Müller-Stich
BackgroundLaparoscopy training courses have been established in many centers worldwide to ensure adequate skill learning before performing operations on patients. Different training modalities and their combinations have been compared regarding training effects. Multimodality training combines different approaches for optimal training outcome. However, no standards currently exist for the number of trainees assigned per workplace.MethodsThis is a monocentric, open, three-arm randomized controlled trial. The participants are laparoscopically-naive medical students from Heidelberg University. After a standardized introduction to laparoscopic cholecystectomy (LC) with online learning modules, the participants perform a baseline test for basic skills and LC performance on a virtual reality (VR) trainer. A total of 100 students will be randomized into three study arms, in a 2:2:1 ratio. The intervention groups participate individually (Group 1) or in pairs (Group 2) in a standardized and structured multimodality training curriculum. Basic skills are trained on the box and VR trainers. Procedural skills and LC modules are trained on the VR trainer. The control group (Group C) does not receive training between tests. A post-test is performed to reassess basic skills and LC performance on the VR trainer. The performance of a cadaveric porcine LC is then measured as the primary outcome using standardized and validated ratings by blinded experts with the Objective Structured Assessment of Technical Skills. The Global Operative Assessment of Laparoscopic Surgical skills score and the time taken for completion are used as secondary outcome measures as well as the improvement of skills and VR LC performance between baseline and post-test. Cognitive tests and questionnaires are used to identify individual factors that might exert influence on training outcome.DiscussionThis study aims to assess whether workplaces in laparoscopy training courses for beginners should be used by one trainee or two trainees simultaneously, by measuring the impact on operative performance and learning curves. Possible factors of influence, such as the role of observing the training partner, exchange of thoughts, active reflection, model learning, motivation, pauses, and sympathy will be explored in the data analysis. This study will help optimize the efficiency of laparoscopy training courses.Trial registration numberDRKS00004675
BMC Surgery | 2013
Felix Nickel; Matthias Müller-Eschner; Jackson Chu; Hendrik von Tengg-Kobligk; Beat P. Müller-Stich
BackgroundBouveret’s syndrome causes gastric outlet obstruction when a gallstone is impacted in the duodenum or stomach via a bilioenteric fistula. It is a rare condition that causes significant morbidity and mortality and often occurs in the elderly with significant comorbidities. Individual diagnostic and treatment strategies are required for optimal management and outcome. The purpose of this paper is to develop a surgical strategy for optimized individual treatment of Bouveret’s syndrome based on the available literature and motivated by our own experience.Case presentationTwo cases of Bouveret’s syndrome are presented with individual management and restrictive surgical approaches tailored to the condition of the patients and intraoperative findings.ConclusionsImproved diagnostics and restrictive individual surgical approaches have shown to lower the mortality rates of Bouveret’s syndrome. For optimized outcome of the individual patient: The medical and perioperative management and time of surgery are tailored to the condition of the patient. CT-scan is most often required to secure the diagnosis. The surgical approach includes enterolithotomy alone or in combination with simultaneous or subsequent cholecystectomy and fistula repair. Lower overall morbidity and mortality are in favor of restrictive surgical approaches. The surgical strategy is adapted to the intraoperative findings and to the risk for secondary complications vs. the age and comorbidities of the patient.
Surgical Endoscopy and Other Interventional Techniques | 2015
Hannes Kenngott; J. J. Wünscher; Martin Wagner; Anas Preukschas; Anna-Laura Wekerle; P. Neher; Stefan Suwelack; Stefanie Speidel; Felix Nickel; D. Oladokun; Lena Maier-Hein; Rüdiger Dillmann; Hans-Peter Meinzer; B. P. Müller-Stich
AbstractBackgroundApart from animal testing and clinical trials, surgical research and laparoscopic training mainly rely on phantoms. The aim of this project was to design a phantom with realistic anatomy and haptic characteristics, modular design and easy reproducibility. The phantom was named open-source Heidelberg laparoscopic phantom (OpenHELP) and serves as an open-source platform. MethodsThe phantom was based on an anonymized CT scan of a male patient. The anatomical structures were segmented to obtain digital three-dimensional models of the torso and the organs. The digital models were materialized via rapid prototyping. One flexible, using an elastic abdominal wall, and one rigid method, using a plastic shell, to simulate pneumoperitoneum were developed. Artificial organ production was carried out sequentially starting from raw gypsum models to silicone molds to final silicone casts. The reproduction accuracy was exemplarily evaluated for ten silicone rectum models by comparing the digital 3D surface of the original rectum with CT scan by calculating the root mean square error of surface variations. Haptic realism was also evaluated to find the most realistic silicone compositions on a visual analog scale (VAS, 0–10).ResultsThe rigid and durable plastic torso and soft silicone organs of the abdominal cavity were successfully produced. A simulation of pneumoperitoneum could be created successfully by both methods. The reproduction accuracy of ten silicone rectum models showed an average root mean square error of 2.26 (0–11.48) mm. Haptic realism revealed an average value on a VAS of 7.25 (5.2–9.6) for the most realistic rectum.ConclusionThe OpenHELP phantom proved to be feasible and accurate. The phantom was consecutively applied frequently in the field of computer-assisted surgery at our institutions and is accessible as an open-source project at www.open-cas.org for the academic community.
Journal of Pediatric Surgery | 2014
Philipp Romero; O. Brands; Felix Nickel; B. Müller; Patrick Günther; Stefan Holland-Cunz
BACKGROUND Intracorporeal suturing and knot tying (ICKT) in minimal invasive surgery (MIS) represents a key skill for advanced procedures. Different methods exist for measuring knot quality and performance, but the heterogeneity of these methods makes direct comparisons difficult. The aim of this study is to compare the quality of a laparoscopic knot to one that is performed open. METHODS To compare open and laparoscopic knot-tying methods we used a surgeons square knot. For laparoscopic knot tying we used a Pelvitrainer. The 32 participants were divided among 4 groups of different skill levels. Group 1 consisted of 6 senior physicians. Group 2 was made up of 10 first to fourth year interns. Groups 3 and 4 contained 16 medical students who had never performed either laparoscopic procedures or open sutures before. Group 3 participants received a 1-hour hands-on training in suturing, whereas group 4 participants received no prior training. Total time, knot quality, suture placement accuracy, and performance defined the parameters for assessment in this study. RESULTS All participants, irrespective of education level were inferior in ICKT compared to open suturing. Only Group 1 showed no significant difference in knot quality and accuracy between the open and laparoscopic suture performance. CONCLUSION It is well documented that psychomotor skills need to be developed before more advanced skills can be put into practice. Training centres for minimally invasive surgery should be an integral part of surgical education. The variables in our study are meaningful and easy to implement. They can be used to measure personal progress and as objective parameters in the development of laparoscopic trainee education.
Surgery for Obesity and Related Diseases | 2017
Felix Nickel; Lukas Schmidt; Thomas Bruckner; Markus W. Büchler; B. P. Müller-Stich; Lars Fischer
BACKGROUND It has been proven that bariatric surgery affects weight loss. Patients with morbid obesity have a significantly lower quality of life (QOL) and body image compared with the general population. OBJECTIVE To evaluate QOL, body image, and general self-efficacy (GSE) in patients with morbid obesity undergoing bariatric surgery within clinical parameters. SETTINGS Monocentric, prospective, longitudinal cohort study. METHODS Patients completed the short form 36 (SF-36) for QOL, body image questionnaire, and GSE scale 3 times: before surgery and within 6 months and 24 months after surgery. Influence of gender, age, and type of procedure, either laparoscopic sleeve gastrectomy (SG) or laparoscopic Roux-en-Y gastric bypass, were analyzed. RESULTS Thirty patients completed the questionnaires before and within 6 and 24 months after surgery. SF-36 physical summary score improved significantly from 34.3±11.0 before surgery to 46.0±10.4 within 6 months (P<.001) and to 49.8±8.2 within 24 months (P<.001) after surgery. SF-36 mental summary score improved significantly from 42.1±14.7 before surgery to 52.3±8.4 within 6 months (P<.001) and to 48.4±12.2 within 24 months (P<.001) after surgery. There were no significant differences between gender, age, and type of operation. Body image and GSE improved significantly after bariatric surgery (P<.001), and both correlated to the SF-36 mental summary score. CONCLUSION QOL, body image, and GSE improved significantly within 6 months and remained stable within 24 months after bariatric surgery. Improvements were independent of gender, age, and type of operation. Mental QOL was influenced by body image and GSE.
Surgical Endoscopy and Other Interventional Techniques | 2017
Karl-Friedrich Kowalewski; Jonathan D. Hendrie; Mona W. Schmidt; Tanja Proctor; Sai Paul; Carly R. Garrow; Hannes Kenngott; Beat P. Müller-Stich; Felix Nickel
BackgroundTouch Surgery™ (TS) is a serious gaming application for cognitive task simulation and rehearsal of key steps in surgical procedures. The aim was to establish face, content, and construct validity of TS for laparoscopic cholecystectomy (LC). Furthermore, learning curves with TS and a virtual reality (VR) trainer were compared in a randomized trial.MethodsThe performance of medical students and general surgeons was compared for all three modules of LC in TS to establish construct validity. Questionnaires assessed face and content validity. For analysis of learning curves, students were randomized to train on VR or TS first, and then switched to the other training modality. Performance data were recorded.Results54 Surgeons and 51 medical students completed the validation study. Surgeons outperformed students with TS: patient preparation (students = 45.0 ± 19.1%; surgeons = 57.3 ± 15.2%; p < 0.001), access and laparoscopy (students = 70.2 ± 10.9%; surgeons = 75.9 ± 9.7%; p = 0.008) and LC (students = 69.8 ± 12.4%; surgeons = 77.7 ± 9.6%; p < 0.001). Both groups agreed that TS was a highly useful and realistic application. 46 students were randomized for learning curve analysis. It took them 2–4 attempts to reach a 100% score with TS. Training with TS first did not improve students’ performance on the VR trainer; however, students who trained with VR first scored significantly higher in module 3 of TS.ConclusionTS is an accepted serious gaming application for learning cognitive aspects of LC with established construct, face, and content validity. There appeared to be a synergy between TS and the VR trainer. Therefore, the two training modalities should accompany one another in a multimodal training approach to laparoscopy.