Beat P. Müller-Stich

A systematic review and meta-analysis of laparoscopic versus open distal pancreatectomy for benign and malignant lesions of the pancreas: it's time to randomize.

BACKGROUND Laparoscopic distal pancreatectomy is regarded as a feasible and safe surgical alternative to open distal pancreatectomy for lesions of the pancreatic tail and body. The aim of the present systematic review was to provide recommendations for clinical practice and research on the basis of surgical morbidity, such as pancreas fistula, delayed gastric empting, safety, and clinical significance of laparoscopic versus open distal pancreatectomy for malignant and nonmalignant diseases of the pancreas. METHODS A systematic literature search (MEDLINE) was performed to identify all types of studies comparing laparoscopic distal pancreatectomy and open distal pancreatectomy. Random effects meta-analyses were calculated after critical appraisal of the included studies and presented as odds ratios or mean differences each with corresponding 95% confidence intervals. RESULTS A total of 4,148 citations were retrieved initially; available data of 29 observational studies (3,701 patients overall) were included in the meta-analyses. Five systematic reviews on the same topic were found and critically appraised. Meta-analyses showed superiority of laparoscopic distal pancreatectomy in terms of blood loss, time to first oral intake, and hospital stay. All other parameters of operative morbidity and safety showed no difference. Data on oncologic radicality and effectiveness are limited. CONCLUSION Laparoscopic distal pancreatectomy seems to be a safe and effective alternative to open distal pancreatectomy. No more nonrandomized trials are needed within this context. A large, randomized trial is warranted and should focus on oncologic effectiveness, defined end points, and cost-effectiveness.

In vivo accuracy assessment of a needle-based navigation system for CT-guided radiofrequency ablation of the liver.

Computed tomography (CT)-guided percutaneous radiofrequency ablation (RFA) has become a commonly used procedure in the treatment of liver tumors. One of the main challenges related to the method is the exact placement of the instrument within the lesion. To address this issue, a system was developed for computer-assisted needle placement which uses a set of fiducial needles to compensate for organ motion in real time. The purpose of this study was to assess the accuracy of the system in vivo. Two medical experts with experience in CT-guided interventions and two nonexperts used the navigation system to perform 32 needle insertions into contrasted agar nodules injected into the livers of two ventilated swine. Skin-to-target path planning and real-time needle guidance were based on preinterventional 1 mm CT data slices. The lesions were hit in 97% of all trials with a mean user error of 2.4 +/- 2.1 mm, a mean target registration error (TRE) of 2.1 +/- 1.1 mm, and a mean overall targeting error of 3.7 +/- 2.3 mm. The nonexperts achieved significantly better results than the experts with an overall error of 2.8 +/- 1.4 mm (n=16) compared to 4.5 +/- 2.7 mm (n=16). The mean time for performing four needle insertions based on one preinterventional planning CT was 57 +/- 19 min with a mean setup time of 27 min, which includes the steps fiducial insertion (24 +/- 15 min), planning CT acquisition (1 +/- 0 min), and registration (2 +/- 1 min). The mean time for path planning and targeting was 5 +/- 4 and 2 +/- 1 min, respectively. Apart from the fiducial insertion step, experts and nonexperts performed comparably fast. It is concluded that the system allows for accurate needle placement into hepatic tumors based on one planning CT and could thus enable considerable improvement to the clinical treatment standard for RFA procedures and other CT-guided interventions in the liver. To support clinical application of the method, optimization of individual system modules to reduce intervention time is proposed.

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.

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.

Outcome of surgery for pancreatic neuroendocrine neoplasms

The incidence of pancreatic neuroendocrine neoplasms (pNEN) is increasing. This study aimed to evaluate predictors of overall survival and the indication for surgery.

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.

Soft tissue navigation for laparoscopic partial nephrectomy

PurposeMinimally invasive surgery of kidney cancer has become a standard therapy method for renal carcinomas. Due to improvements in diagnosis, carcinomas tend to be detected with a smaller size, which often allows for a tissue sparing, laparoscopic partial nephrectomy (LPN). Successful LPN requires a safe resection line inside the kidney, which spares most of healthy tissue, while assuring the complete tumor removal. This paper proposes an approach for a real-time visualization aid during LPN.MethodsA surgical soft tissue navigation system for laparoscopic was designed, implemented and tested in vitro. The system enhances the surgeon’s perception to provide decision guidance directly before initiation of kidney resection. Preoperative planning, intraoperative imaging, and real-time image processing are incorporated in a system that can enhance an endoscope’s image by superimposing relevant medical information like tumor infiltrated tissue and risk structures. This system has a flexible design to facilitate its integration into surgical work flows. The system evaluation was divided into two parts: (1) a virtual evaluation environment, which allows for simulation of all involved system parameters; (2) in vitro surgeries were performed using a laparoscopic training unit to evaluate the overall robustness and accuracy of the navigation system with real data.ResultsThe system was implemented and tested in vitro with favorable results. Real-time video recording of its operation was done to demonstrate the ability to simultaneously visualize the renal collecting system, major blood vessels, and abnormal lesion.ConclusionLaparoscopic partial nephrectomy can benefit from surgical computer assistance with preoperative planning, intraoperative imaging, and real time guidance integrated in a single system. The presented surgical navigation approach is suitable for testing in an intraoperative environment with human patients undergoing LPN.

Robotic-assisted transhiatal esophagectomy

BackgroundDespite its reduced aggressiveness and excellent results obtained in certain diseases, minimally invasive surgery did not manage to significantly lower the risks of esophageal resections. Further advances in technology led to the creation of robotic systems with their unique maneuverability of the instruments and exceptional view on the operative field, thus setting the prerequisites for performance in complex surgical procedures and offering new possibilities to a disease notorious for its dismal prognosis.Materials and methodsThe robotic-assisted transhiatal esophagectomy technique was used in a patient with squamous cell carcinoma of the lower esophagus that had high medical risk for surgical therapy.ResultsEsophageal resection and reconstruction were possible through a robotic-assisted minimally invasive transhiatal approach. There were no intraoperative incidents, blood loss was minimal, and lymph node dissection and removal was possible during the procedure. Early ambulation and conservative treatment of the mild complications that occurred offered a favorable postoperative outcome.ConclusionThe robotic-assisted transhiatal esophagectomy technique is feasible and safe. Complex procedures become less technically demanding with the help of the robotic system and, thus, the minimally invasive approach can be offered for the benefit of selected patients. Further studies are required to confirm these observations and to establish the role of this procedure in the future.

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.

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.