Hannes Kenngott

Surgical versus medical treatment of type 2 diabetes mellitus in nonseverely obese patients: a systematic review and meta-analysis.

OBJECTIVE To compare surgical versus medical treatment of type 2 diabetes mellitus (T2DM) remission and comorbidities in patients with a body mass index (BMI) less than 35 kg/m2. BACKGROUND Obesity surgery can achieve remission of T2DM and its comorbidities. Metabolic surgery has been proposed as a treatment option for diabetic patients with BMI less than 35 kg/m2 but the efficacy of metabolic surgery has not been conclusively determined. METHODS A systematic literature search identified randomized (RCT) and nonrandomized comparative observational clinical studies (OCS) evaluating surgical versus medical T2DM treatment in patients with BMI less than 35 kg/m2. The primary outcome was T2DM remission. Additional analyses comprised glycemic control, BMI, HbA1c level, remission of comorbidities, and safety. Random effects meta-analyses were calculated and presented as weighted odds ratio (OR) or mean difference (MD) with 95% confidence intervals (95% CI). RESULTS Five RCTs and 6 OCSs (706 total T2DM patients) were included. Follow-up ranged from 12 to 36 months. Metabolic surgery was associated with a higher T2DM remission rate (OR: 14.1, 95% CI: 6.7-29.9, P < 0.001), higher rate of glycemic control (OR: 8.0, 95% CI: 4.2-15.2, P < 0.001) and lower HbA1c level (MD: -1.4%, 95% CI -1.9% to -0.9%, P < 0.001) than medical treatment. BMI (MD -5.5 kg/m2, 95% CI: -6.7 to -4.3 kg/m2, P < 0.001), rate of arterial hypertension (OR: 0.25, 95% CI: 0.12-0.50, P < 0.001) and dyslipidemia (OR: 0.21, 95% CI: 0.10-0.44, P < 0.001) were lower after surgery. CONCLUSION Metabolic surgery is superior to medical treatment for short-term remission of T2DM and comorbidities. Further RCTs should address the long-term effects on T2DM complications and mortality.

Comparative Validation of Single-Shot Optical Techniques for Laparoscopic 3-D Surface Reconstruction

Intra-operative imaging techniques for obtaining the shape and morphology of soft-tissue surfaces in vivo are a key enabling technology for advanced surgical systems. Different optical techniques for 3-D surface reconstruction in laparoscopy have been proposed, however, so far no quantitative and comparative validation has been performed. Furthermore, robustness of the methods to clinically important factors like smoke or bleeding has not yet been assessed. To address these issues, we have formed a joint international initiative with the aim of validating different state-of-the-art passive and active reconstruction methods in a comparative manner. In this comprehensive in vitro study, we investigated reconstruction accuracy using different organs with various shape and texture and also tested reconstruction robustness with respect to a number of factors like the pose of the endoscope as well as the amount of blood or smoke present in the scene. The study suggests complementary advantages of the different techniques with respect to accuracy, robustness, point density, hardware complexity and computation time. While reconstruction accuracy under ideal conditions was generally high, robustness is a remaining issue to be addressed. Future work should include sensor fusion and in vivo validation studies in a specific clinical context. To trigger further research in surface reconstruction, stereoscopic data of the study will be made publically available at www.open-CAS.com upon publication of the paper.

Dense GPU‐enhanced surface reconstruction from stereo endoscopic images for intraoperative registration

PURPOSE In laparoscopic surgery, soft tissue deformations substantially change the surgical site, thus impeding the use of preoperative planning during intraoperative navigation. Extracting depth information from endoscopic images and building a surface model of the surgical field-of-view is one way to represent this constantly deforming environment. The information can then be used for intraoperative registration. Stereo reconstruction is a typical problem within computer vision. However, most of the available methods do not fulfill the specific requirements in a minimally invasive setting such as the need of real-time performance, the problem of view-dependent specular reflections and large curved areas with partly homogeneous or periodic textures and occlusions. METHODS In this paper, the authors present an approach toward intraoperative surface reconstruction based on stereo endoscopic images. The authors describe our answer to this problem through correspondence analysis, disparity correction and refinement, 3D reconstruction, point cloud smoothing and meshing. Real-time performance is achieved by implementing the algorithms on the gpu. The authors also present a new hybrid cpu-gpu algorithm that unifies the advantages of the cpu and the gpu version. RESULTS In a comprehensive evaluation using in vivo data, in silico data from the literature and virtual data from a newly developed simulation environment, the cpu, the gpu, and the hybrid cpu-gpu versions of the surface reconstruction are compared to a cpu and a gpu algorithm from the literature. The recommended approach toward intraoperative surface reconstruction can be conducted in real-time depending on the image resolution (20 fps for the gpu and 14fps for the hybrid cpu-gpu version on resolution of 640 × 480). It is robust to homogeneous regions without texture, large image changes, noise or errors from camera calibration, and it reconstructs the surface down to sub millimeter accuracy. In all the experiments within the simulation environment, the mean distance to ground truth data is between 0.05 and 0.6 mm for the hybrid cpu-gpu version. The hybrid cpu-gpu algorithm shows a much more superior performance than its cpu and gpu counterpart (mean distance reduction 26% and 45%, respectively, for the experiments in the simulation environment). CONCLUSIONS The recommended approach for surface reconstruction is fast, robust, and accurate. It can represent changes in the intraoperative environment and can be used to adapt a preoperative model within the surgical site by registration of these two models.

Status of robotic assistance--a less traumatic and more accurate minimally invasive surgery?

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.

Robotic suturing: technique and benefit in advanced laparoscopic surgery.

Suturing is one of the main tasks in advanced laparoscopic surgery, but limited degrees of freedom, 2D vision, fulcrum and pivoting effect make it difficult to perform. Robotic systems provide corresponding solutions as three‐dimensional (3D) view, intuitive motion and additional degrees of freedom. This review evaluates these benefits for their impact on suturing in experimental and clinical studies. The Medline database was searched for “robot*, telemanipulat* and laparoscop*”. A total of 1150 references were found and further limited to “suturing” for experimental evaluation, finding 89 references. All references were considered for information on robotic suturing in advanced laparoscopy. Further references were obtained through cross‐referencing the bibliography cited in each work. In experimental studies current robotic systems have proven their superior suturing capabilities compared to conventional laparoscopic techniques, mainly attributed to 3D visualization and full seven degrees of freedom. In clinical studies these benefits have not yet been sufficiently reproduced. Robotic systems have to prove the benefits shown in experimental studies for suturing tasks in clinical applications. Robotic devices shorten the learning curve of laparoscopic procedures. Further clinical trials focusing on anastomosis time are needed to assess this question.

Can Masses of Non-Experts Train Highly Accurate Image Classifiers?

Machine learning algorithms are gaining increasing interest in the context of computer-assisted interventions. One of the bottlenecks so far, however, has been the availability of training data, typically generated by medical experts with very limited resources. Crowdsourcing is a new trend that is based on outsourcing cognitive tasks to many anonymous untrained individuals from an online community. In this work, we investigate the potential of crowdsourcing for segmenting medical instruments in endoscopic image data. Our study suggests that (1) segmentations computed from annotations of multiple anonymous non-experts are comparable to those made by medical experts and (2) training data generated by the crowd is of the same quality as that annotated by medical experts. Given the speed of annotation, scalability and low costs, this implies that the scientific community might no longer need to rely on experts to generate reference or training data for certain applications. To trigger further research in endoscopic image processing, the data used in this study will be made publicly available.

The past, present and future of minimally invasive therapy in urology: A review and speculative outlook

Abstract Introduction: Twenty-five years of SMIT represents an important date. In this article we want to elaborate the development of minimally invasive surgery in urology during the last three decades and try to look 25 years ahead. Material and methods: As classical scenarios to demonstrate the changes which have revolutionized surgical treatment in urology, we have selected the management of urolithiasis, renal tumour, and localized prostate cancer. This was based on personal experience and a review of the recent literature on MIS in Urology on a MEDLINE/PUBMED research. For the outlook to the future, we have taken the expertise of two senior urologists, middle-aged experts, and upcoming junior fellows, respectively. Results: Management of urolithiasis has been revolutionized with the introduction of non-invasive extracorporeal shock wave lithotripsy (ESWL) and minimally invasive endourology in the mid-eighties of the last century obviating open surgery. This trend has been continued with perfection and miniaturization of endourologic armamentarium rather than significantly improving ESWL. The main goal is now to get rid of the stone in one session rather in multiple non-invasive treatment sessions. Stone treatment 25 years from today will be individualized by genetic screening of stone formers, using improved ESWL-devices for small stones and transuretereal or percutaneous stone retrieval for larger and multiple stones. Management of renal tumours has also changed significantly over the last 25 years. In 1988, open radical nephrectomy was the only therapeutic option for renal masses. Nowadays, tumour size determines the choice of treatment. Tumours >4 cm are usually treated by laparoscopic nephrectomy, smaller tumours, however, can be treated either by open, laparoscopic or robot-assisted partial nephrectomy. For patients with high co-morbidity focal tumour ablation or even active surveillance represents a viable option. In 25 years, imaging of tumours will further support early diagnosis, but will also be able to determine the pathohistological pattern of the tumour to decide whether the patient requires removal, ablation or active surveillance. Management of localized prostate cancer underwent significant changes as well. 25 years ago open retropubic nerve-sparing radical prostatectomy was introduced as the optimal option for effective treatment of the cancer providing minimal side-effects. Basically, the same operation is performed today, but with robot-assisted laparoscopic techniques providing 7-DOF instruments, 3D-vision and tenfold magnification and enabling the surgeon to work in a sitting position at the console. In 25 years, prostate cancer may be managed in most cases by focal therapy and/or genetically targeting therapy. Only a few patients may still require robot-assisted removal of the entire gland. Discussion: There has been a dramatic change in the management of the most frequent urologic diseases almost completely replacing open surgery by minimally invasive techniques. This was promoted by technical realisation of physical principles (shock waves, optical resolution, master-slave system) used outside of medicine. The future of medicine may lie in translational approaches individualizing the management based on genetic information and focalizing the treatment by further improvement of imaging technology.

Virtual Reality Training Versus Blended Learning of Laparoscopic Cholecystectomy: A Randomized Controlled Trial With Laparoscopic Novices

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.

Physics‐based shape matching for intraoperative image guidance

PURPOSE Soft-tissue deformations can severely degrade the validity of preoperative planning data during computer assisted interventions. Intraoperative imaging such as stereo endoscopic, time-of-flight or, laser range scanner data can be used to compensate these movements. In this context, the intraoperative surface has to be matched to the preoperative model. The shape matching is especially challenging in the intraoperative setting due to noisy sensor data, only partially visible surfaces, ambiguous shape descriptors, and real-time requirements. METHODS A novel physics-based shape matching (PBSM) approach to register intraoperatively acquired surface meshes to preoperative planning data is proposed. The key idea of the method is to describe the nonrigid registration process as an electrostatic-elastic problem, where an elastic body (preoperative model) that is electrically charged slides into an oppositely charged rigid shape (intraoperative surface). It is shown that the corresponding energy functional can be efficiently solved using the finite element (FE) method. It is also demonstrated how PBSM can be combined with rigid registration schemes for robust nonrigid registration of arbitrarily aligned surfaces. Furthermore, it is shown how the approach can be combined with landmark based methods and outline its application to image guidance in laparoscopic interventions. RESULTS A profound analysis of the PBSM scheme based on in silico and phantom data is presented. Simulation studies on several liver models show that the approach is robust to the initial rigid registration and to parameter variations. The studies also reveal that the method achieves submillimeter registration accuracy (mean error between 0.32 and 0.46 mm). An unoptimized, single core implementation of the approach achieves near real-time performance (2 TPS, 7-19 s total registration time). It outperforms established methods in terms of speed and accuracy. Furthermore, it is shown that the method is able to accurately match partial surfaces. Finally, a phantom experiment demonstrates how the method can be combined with stereo endoscopic imaging to provide nonrigid registration during laparoscopic interventions. CONCLUSIONS The PBSM approach for surface matching is fast, robust, and accurate. As the technique is based on a preoperative volumetric FE model, it naturally recovers the position of volumetric structures (e.g., tumors and vessels). It cannot only be used to recover soft-tissue deformations from intraoperative surface models but can also be combined with landmark data from volumetric imaging. In addition to applications in laparoscopic surgery, the method might prove useful in other areas that require soft-tissue registration from sparse intraoperative sensor data (e.g., radiation therapy).

Gastric bypass leads to improvement of diabetic neuropathy independent of glucose normalization--results of a prospective cohort study (DiaSurg 1 study).

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.