Robot-assisted magnetic capsule endoscopy; navigating colorectal inclinations.

Purpose: To investigate the interaction of a robot assisted magnetically driven wireless capsule endoscope (WCE) with colonic tissue, as it traverses the colorectal bends in the dorsal and ventral directions, relying only on the feedback from a 3D accelerometer. We also investigate the impact of shell geometry and water insufflation on WCE locomotion.Methods: A 3D printed incline phantom, lined with porcine colon, was used as the experimental platform, for controlled and repeatable results. The tilt angle of WCE was controlled to observe its influence on WCE locomotion. The phantom was placed underwater to observe the effects of water insufflation. The experiments were repeated using the two capsule shell geometries to observe the effect of shell geometry on WCE locomotion.Results: Friction between WCE and intestinal tissue increased when the tilt angle of the WCE was lower than the angle of the incline of the phantom. Increasing the WCE tilt angle to match the angle of the incline reduced this friction. Water insufflation and elliptical capsule shell geometry reduced the friction further.Conclusion: Tilting of the WCE equal to, or more than the angle of the incline improved the WCE locomotion. WCE locomotion was also improved by using elliptical capsule shell geometry and water insufflation.Abbreviations: CRC: colorectal cancer; GI: gastrointestinal; MRI: magnetic resonance imaging; WCE: wireless capsule endoscope.

Bariatric reduction system - BARS: device, technique and first clinical experience.

BACKGROUND: Roux-en-Y gastric by-pass (RYGB) is one of the most effective bariatric procedures, but the rate of weight regain (WR) can reach 63% after the second year. Enlargement of the gastrojejunal anastomosis is one of the reported causes. A newly CE-marked flexible endoscopic system, Bariatric Anastomotic Reduction System (BARS) (Ovesco Endoscopy, Tuebingen, Germany), derivative of the well-established endoscopic over-the-scope-clip (OTSC) clipping system, has been recently developed. It was tested in pre-clinical and preliminary clinical use for feasibility and effectiveness in bariatric anastomotic reduction. MATERIAL AND METHODS: Using a single-channel endoscope with external supplemental working channel, the BARS device captures the two limbs of the anastomosis, reducing its size, thus slowing food passage. After preclinical assessment, six patients with at least a 15% WR and the presence of an enlarged gastrojejunostomy > 20 mm were enrolled. The mean patient age was 49 years (range 24-67). Average interval between gastric bypass and BARS procedure: 8 years (4-13). RESULTS: All procedures were safely performed without complications. Mean procedure time: 52 min (37 - 75). Preliminary results: mean weight loss 6 kg (4-9) at a 3-month FU. CONCLUSIONS: BARS could be a promising endoscopic system in case of WR after gastric bypass due to enlargement of the anastomosis.

Pre-clinical study on a telemetric gastric sensor for recognition of acute upper gastrointestinal bleeding: the "HemoPill monitor".

BACKGROUND: Acute upper gastrointestinal bleeding is a life-threatening medical condition with a relevant risk of re-bleeding even after initial endoscopic hemostasis. The implantable HemoPill monitor contains a novel telemetric sensor to optically detect blood in the stomach allowing the surveillance of high-risk patients for re-bleedings. METHODS: In this pre-clinical porcine study, bleeding has been simulated by injecting porcine blood into the stomach of a pig through an implanted catheter using a syringe pump. The effect of the sensor position in the stomach, the gastric food content, and the bleeding intensity was investigated. RESULTS: Sensitivity and specificity of the sensor reached more than 87.5% when the sensor was positioned close to the source of bleeding. Solid food had a higher negative impact on sensitivity than liquid food but a positive impact on specificity. A heavy bleeding was more likely to be detected by the sensor but was also associated with a lower likelihood for true-negative results than weaker bleedings. CONCLUSIONS: The study clearly demonstrated the capability of the HemoPill sensor prototype to detect clinically relevant bleedings with high sensitivity and specificity (> 80%) when the sensor was positioned close to the bleeding site. The sensors proved to be robust against artefact effects from stomach content. These are favorable findings that underline the potential benefit for the use of the HemoPill sensor in monitoring patients with a risk of re-bleeding in the upper gastrointestinal tract.

Efficacy of the OTSC System in the treatment of GI bleeding and wall defects: a PMCF meta-analysis.

Since its market launch in 2007, the endoscopic OTSC clipping system has been the object of intensive clinical research. These data were systematically collected for post-market clinical follow-up (PMCF). The aim of the study was the systematic review of the efficacy and safety of the OTSC System. The PMCF database was systematically searched for clinical data on OTSC therapy of GI hemorrhage (H), acute leaks/perforations (AL) and chronic leaks/fistulae (CL). Major outcomes were successful clip application and durable hemostasis/closure of defects. Comprehensive pooled success proportions were established by meta-analytical methods. Four-hundred-fifty-seven publications were reviewed. Fifty-eight articles comprising 1868 patients fulfilled criteria to be included in the analysis. These consisted of retrospective analyses, prospective observational trials, one randomized-controlled trial (STING) and one quasi-controlled study (FLETRock). The pooled proportion analysis revealed high overall proportions of technical success: H - mean 93.0% [95%CI 90.2-95.4], AL-mean 89.7% [95%CI 85.9-92.9] and CL-mean 83.8% [95%CI 76.9-89.7]. Pooled durable clinical success proportions were: H-mean 87.5% [95%CI 80.5-93.2], AL-mean 81.4% [95%CI 77.0-85.3] and CL-mean 63.0% [95%CI 53.0-72.3]. By pooling all clinical data gained, we conclude that OTSC application in GI hemorrhage and closure of GI lesions is safe and effective in real clinical use.

Ontology-based specification and generation of search queries for post-market surveillance.

BACKGROUND: The vigilant observation of medical devices during post-market surveillance (PMS) for identifying safety-relevant incidents is a non-trivial task. A wide range of sources has to be monitored in order to integrate all accessible data about the safety and performance of a medical device. PMS needs to be supported by an efficient search strategy and the possibility to create complex search queries by domain experts. RESULTS: We use ontologies to support the specification of search queries and the preparation of the document corpus, which contains all relevant documents. In this paper, we present (1) the Search Ontology (SON) v2.0, (2) an Excel template for specifying search queries, and (3) the Search Ontology Generator (SONG), which generates complex queries out of the Excel template. Based on our approach, a service-oriented architecture was designed, which supports and assists domain experts during PMS. Comprehensive testing confirmed the correct execution of all SONG functions. The applicability of our method and of the developed tools was evaluated by domain experts. The test persons concordantly rated our solution after a short period of training as highly user-friendly, intuitive and well applicable for supporting PMS. CONCLUSIONS: The Search Ontology is a promising domain-independent approach to specify complex search queries. Our solution allows advanced searches for relevant documents in different domains using suitable domain ontologies.

Preclinical evaluation of a novel thermally sensitive co-polymer (LiftUp) for endoscopic resection.

Introduction: Endoscopic resection techniques can successfully resect large lesions either in "en bloc" fashion or in "piece-meal" technique by using a submucosal injection solution. The aim of this study was to evaluate the safety of a novel injectable, containing thermally sensitive co-polymer from ethylenoxide and propylenoxide (LiftUp) used as submucosal injection solution.Material and methods: We conducted an in vivo animal trial in the porcine model to evaluate the LiftUp gel in a preclinical setting and to study the effectiveness of mucosal lifting and the safety of the new injectable. In seven animals a total of 63 injections and endoscopic resections were carried out in different anatomical locations (esophagus, stomach and rectum). The resection sites were controlled endoscopically one and four weeks after resection and a histopathological evaluation of the resection sites was performed after four weeks.Results: The application of LiftUp was safe and there were no negative effects on wound healing after injection and resection. A major procedural complication rate (defined as perforation and major haemorrhage) of 3.2% was registered, which undercuts the anticipated mean complication rate of 4-8%. Furthermore, there was no necessity of reinjection after the initial submucosal injection in 90.5% and no procedural complications in 98.8%. The histopathological examination of the tissue samples indicated normal wound healing with granulation tissue and epithelialisation.Conclusion: The use of LiftUp as submucosal injection solution was feasible for different endoscopic resection techniques, with high and long-lasting elevation and fewer procedural adverse events than expected at trial planning. The new injectable is a practical advancement over the current state-of-the-art of submucosal injection and could fasten up the resection procedure and make endoscopic 'en bloc' resection safer.

Predictive Tilt Compensation for Robot Assisted Magnetic Capsule Endoscope.

Wireless capsule endoscopes provide a painless and non-invasive alternative to the flexible endoscope in various applications of the gastrointestinal tract diagnosis. Operating a wireless capsule endoscope in the colon may benefit from an active position control as the large colon diameter can lead to uncontrollable and unpredictable capsule trajectory. Robot assisted magnetic steering is an attractive technique that is being explored by researchers worldwide. This paper presents the implications of a novel capsule geometry to markedly improve capsule stabilization and locomotion compared to the cylinder-based capsule geometry that is commonly used.

Efficacy and safety of the remOVE System for OTSC® and FTRD® clip removal: data from a PMCF analysis.

INTRODUCTION: The remOVE System (Ovesco Endoscopy AG, Tuebingen, Germany) is a medical device for the endoscopic removal of OTSC or FTRD clips (Ovesco Endoscopy AG, Tuebingen, Germany). The aim of this paper is to assess the efficacy and safety of this system. MATERIAL AND METHODS: A total of 74 patients underwent clip extraction. The standard removal procedure comprises fragmenting the clip by applying an electrical direct current pulse at two opposing sides of the clip. RESULTS: Clip fragmentation was successful in 72 of 74 patients (97.3%). In two cases (2.7%) clip fragmentation was not possible. In nine cases (12.2%) a clip fragment could not be removed and was left in place. Complications occurred in three cases (4.1%): two minor bleedings near the clip removal site (2.7%), and one superficial mucosal tear resulting from clip fragment extraction (1.4%). DISCUSSION: Based on this study, the use of the remOVE System for OTSC or FTRD clip removal can be considered safe and effective.

Future of robotic surgery in urology.

OBJECTIVES: To provide a comprehensive overview of the current status of the field of robotic systems for urological surgery and discuss future perspectives. MATERIALS AND METHODS: A non-systematic literature review was performed using PubMed/Medline search electronic engines. Existing patents for robotic devices were researched using the Google search engine. Findings were also critically analysed taking into account the personal experience of the authors. RESULTS: The relevant patents for the first generation of the da Vinci platform will expire in 2019. New robotic systems are coming onto the stage. These can be classified according to type of console, arrangement of robotic arms, handles and instruments, and other specific features (haptic feedback, eye-tracking). The Telelap ALF-X robot uses an open console with eye-tracking, laparoscopy-like handles with haptic feedback, and arms mounted on separate carts; first clinical trials with this system were reported in 2016. The Medtronic robot provides an open console using three-dimensional high-definition video technology and three arms. The Avatera robot features a closed console with microscope-like oculars, four arms arranged on one cart, and 5-mm instruments with six degrees of freedom. The REVO-I consists of an open console and a four-arm arrangement on one cart; the first experiments with this system were published in 2016. Medicaroid uses a semi-open console and three robot arms attached to the operating table. Clinical trials of the SP 1098-platform using the da Vinci Xi for console-based single-port surgery were reported in 2015. The SPORT robot has been tested in animal experiments for single-port surgery. The SurgiBot represents a bedside solution for single-port surgery providing flexible tube-guided instruments. The Avicenna Roboflex has been developed for robotic flexible ureteroscopy, with promising early clinical results. CONCLUSIONS: Several console-based robots for laparoscopic multi- and single-port surgery are expected to come to market within the next 5 years. Future developments in the field of robotic surgery are likely to focus on the specific features of robotic arms, instruments, console, and video technology. The high technical standards of four da Vinci generations have set a high bar for upcoming devices. Ultimately, the implementation of these upcoming systems will depend on their clinical applicability and costs. How these technical developments will facilitate surgery and whether their use will translate into better outcomes for our patients remains to be determined.

Volunteer Case Series of a New Telemetric Sensor for Blood Detection in the Upper Gastrointestinal Tract: The HemoPill.

BACKGROUND: An acute upper gastrointestinal bleeding event is an emergency situation which requires immediate endoscopic assessment and treatment. A new telemetric real-time intracorporeal bleeding sensor can help in the timely diagnosis of an acute upper gastrointestinal bleeding event: The sensor capsule, HemoPill, is swallowed by the patient if gastrointestinal bleeding is suspected. Information about the bleeding status is displayed by telemetric communication of the capsule with an extracorporeal receiver. This is the first evaluation of the HemoPill to detect blood in the upper human gastrointestinal tract. METHODS: A voluntary test person ate a defined meal with or without the adjunct of his own blood for a total of eight times and afterward swallowed the sensor capsule. The collected spectrometric receiver data were analyzed to assess whether the sensor system was capable of detecting blood and to evaluate the effect of stomach content as an artifact. RESULTS: With its optical sensor, the HemoPill was able to reliably indicate the ingested blood in the stomach. The data transmission from the swallowed sensor capsule to the extracorporeal receiver was achieved consistently. The evaluation of diverse concentrations of ingested blood and the respective sensor signals led to an exponential relationship of these variables. This relationship allows to define thresholds for categories indicating the likelihood of blood presence in the gastrointestinal tract. CONCLUSIONS: The HemoPill is a valuable tool to detect an acute upper gastrointestinal bleeding event without the need of endoscopy.

Design and Performance of a Low-Cost Telemetric Laparoscopic Tactile Grasper.

Tactile feedback is completely lost in laparoscopic surgery, which would provide information about tissue compliance, texture, structural features, and foreign bodies. We developed a system with artificial tactile feedback for laparoscopic surgery that consists of a telemetric tactile laparoscopic grasper, a remote PC with customized software, and a commercial video-mixer. A standard, nonsensorized laparoscopic grasper was customized to allow the integration of a tactile sensor and its electronics. The tactile sensor and the electronics module were designed to be detachable from the instrument. These parts are lightweight and wireless, thus not impeding the use of the device as surgical instrument. The remaining system components used to generate visualization of the tactile data do not influence the workflow in the operating room. The overall system design of the described instrumentation allows for easy implementation in an operating room environment. The fabrication of the tactile sensor is relatively easy and the production costs are low. With this telemetric laparoscopic grasper instrument, systematic preclinical studies can be performed in which surgeons execute surgical tasks that are derived from clinical reality. The experience gained from these investigations could then be used to define the requirements for any further development of artificial tactile feedback systems.

Laparoscopic gastro-jejunal anastomosis using novel r2 deflectable instruments in an ex vivo model.

OBJECTIVE: A novel 5 mm steerable instrument system (r2-DRIVE) was developed with active tip deflection and tip and shaft rotation. The feasibility and training effect of the r2 instruments were determined in a phantom model. MATERIAL AND METHODS: Experienced laparoscopic surgeons and untrained novices performed laparoscopic gastro-jejunal anastomoses using porcine tissue and r2 DRIVE-instruments. Mean anastomosis time, anastomosis width and burst pressure were measured. Number of stitches, skipped stitches and dropped needles were counted. Results of trained and untrained subjects were compared. RESULTS: Mean time for suturing decreased rapidly for all participants, but was more evident for untrained persons. After five anastomoses no relevant improvement in anastomotic time was seen for the skilled group. The ease of use, efficacy of manipulation and swift training effect with the novel r2 instruments for both experienced laparoscopic surgeons and untrained non-surgeons could be demonstrated and after few cases stable anastomosis times and a fast learning curve were obtained. CONCLUSIONS: This study demonstrates the ease of use, efficacy of manipulation and swift training effect with the novel r2 instruments for both experienced laparoscopic surgeons and untrained non-surgeons. After few cases stable anastomosis times and a fast learning curve were obtained.

Porcine survival model to simulate acute upper gastrointestinal bleedings.

The existing animal models used for the simulation of acute gastrointestinal bleedings are usually non-survival models. We developed and evaluated a new porcine model (domestic pig, German Landrace) in which the animal remains alive and survives the artificial bleeding without any cardiovascular impairment. This consists of a bleeding catheter which is implanted into the stomach, then subcutaneously tunnelled from the abdomen to the neck where it is exteriorized and fixed with sutures. Using the injection of porcine blood, controllable and reproducible acute upper gastrointestinal bleeding can be simulated while maintaining normal gastrointestinal motility and physiology. Depending on the volume of blood applied through the gastric catheter, the bleeding intensity can be varied from traces of blood to a massive haemorrhage. This porcine model could be valuable, e.g. for testing the efficacy of new bleeding diagnostics in large animals before human use.

Telemetric real-time sensor for the detection of acute upper gastrointestinal bleeding.

Acute upper gastrointestinal bleedings from ulcers or esophago-gastric varices are life threatening medical conditions which require immediate endoscopic therapy. Despite successful endoscopic hemostasis, there is a significant risk of rebleeding often requiring close surveillance of these patients in the intensive care unit (ICU). Any time delay to recognize bleeding may lead to a high blood loss and increases the risk of death. A novel telemetric real-time bleeding sensor can help indicate blood in the stomach: the sensor is swallowed to detect active bleeding or is anchored endoscopically on the gastrointestinal wall close to the potential bleeding source. By telemetric communication with an extra-corporeal receiver, information about the bleeding status is displayed. In this study the novel sensor, which measures characteristic optical properties of blood, has been evaluated in an ex-vivo setting to assess its clinical applicability and usability. Human venous blood of different concentrations, various fluids, and liquid food were tested. The LED-based sensor was able to reliably distinguish between concentrated blood and other liquids, especially red-colored fluids. In addition, the spectrometric quality of the small sensor (size: 6.5mm in diameter, 25.5mm in length) was comparable to a much larger and technically more complex laboratory spectrophotometer. The experimental data confirm the capability of a miniaturized sensor to identify concentrated blood, which could help in the very near future the detection of upper gastrointestinal bleeding and to survey high-risk patients for rebleeding.

A miniaturized robotic platform for natural orifice transluminal endoscopic surgery: in vivo validation.

BACKGROUND: Natural orifice transluminal endoscopic surgery (NOTES) involves accessing the abdominal cavity via one of the body natural orifices for enabling minimally invasive surgical procedures. However, the constraints imposed by the access modality and the limited available technology make NOTES very challenging for surgeons. Tools redesign and introduction of novel surgical instruments are imperative in order to make NOTES operative in a real surgical scenario, reproducible and reliable. Robotic technology has major potential to overcome current limitations. METHODS: The robotic platform described here consists of a magnetic anchoring frame equipped with dedicated docking/undocking mechanisms to house up to three modular robots for surgical interventions. The magnetic anchoring frame guarantees the required stability for surgical tasks execution, whilst dedicated modular robots provide the platform with adequate vision, stability and manipulation capabilities. RESULTS: Platform potentialities were demonstrated in a porcine model. Assessment was organized into two consecutive experimental steps, with a hybrid testing modality. First, platform deployment, anchoring and assembly through transoral-transgastric access were demonstrated in order to assess protocol feasibility and guarantee the safe achievement of the following experimental session. Second, transabdominal deployment, anchoring, assembly and robotic module actuation were carried out. CONCLUSIONS: This study has demonstrated the feasibility of inserting an endoluminal robotic platform composed of an anchoring frame and modular robotic units into a porcine model through a natural orifice. Once inserted into the peritoneal cavity, the platform provides proper visualization from multiple orientations. For the first time, a platform with interchangeable modules has been deployed and its components have been connected, demonstrating in vivo the feasibility of intra-abdominal assembly. Furthermore, increased dexterity employing different robotic units will enhance future system capabilities.

Endoscopic full-thickness resection and clip defect closure in the colon with the new FTRD system: experimental study.

BACKGROUND: The benefit of endoscopic full-thickness resection is the improved diagnostic work-up with an integral wall specimen which allows a precise determination of the tumor or its precursor and its infiltration depth into the wall. MATERIALS AND METHODS: A new endoscopic full-thickness resection device (FTRD), which is a combination of a modified over-the-scope-clip (OTSC) system with an electrocautery snare, has been tested in an experimental setting. In eleven pigs, divided into three groups, endoscopic full-thickness resection was performed in the colon at one or two sites, respectively. Seven days (n = 7) or 28 days (n = 4) after the intervention, the animals were euthanized following endoscopic examination of the resection and clip application sites. Furthermore, two different clips were tested during these animal trials in order to evaluate the most effective clip design. RESULTS: The average diameter of the tissue resected with the FTRD was 3.1, 3.6, and 5.4 cm in the three groups. On follow-up endoscopy 7 days after the intervention, fibrin coating and stool residues were found at all clips, causing minor inflammatory reactions. However, the colon wall under the clip was non-inflamed. After 28 days, the serosa had primarily healed in all cases. There were also stool residues at all clips; however, no acute inflammatory reactions were seen anymore, due to complete healing. Histological assessment did not show any signs of dehiscence in the region of the scar, or ischemia in the clip area. In addition, no wound infections, such as abscess formation, were observed. CONCLUSIONS: This study demonstrates the safety and efficacy of the clip-and-cut technique using the new FTRD system. With the device, a local full-thickness colon resection can be easily created, and the resulting wall defect is reliably sealed by the endoluminal application of a modified OTSC clip.

Single-port live donor nephrectomy using a novel Curved Radius r2 Surgical System in an in vivo model.

OBJECTIVE: Single-port laparoscopic donor nephrectomy provides low morbidity and satisfactory cosmetic results for patients. The aim of this animal study was to establish a surgical technique of single-site (LESS) living donor nephrectomy using novel curved r2 CURVE manipulators specially designed for single-port access. MATERIAL AND METHODS: A total of six LESS nephrectomies were performed in three female pigs. r2 CURVE-instruments (Tuebingen Scientific Medical GmbH) were used providing a curved rotatable shaft, endless tip rotation, as well as 90° tip deflection. A 10 mm 30° extra long laparoscope, r2-curved Grasper, Maryland dissector and bipolar scissors were used for mobilization and dissection. RESULTS: All LESS nephrectomies were performed successfully. Average operative time was 80 min (range, 42-149 min). No technical problems were observed. Insertion and extraction of the instruments through the single-port were easy to conduct. The diameter of the used single-port was sufficient for safe manual organ harvesting. Potential conflict between the laparoscope and the instrument handles was avoided by using an extra long laparoscope. CONCLUSIONS: The new curved and deflectable instruments showed that single-port nephrectomy using the R2 manipulators is feasible. Single-port laparoscopic nephrectomy might be more patient-friendly and improve the willingness of potential donors to donate live organs.

in vivo ischemia monitoring array for endoscopic surgery.

An array with all-solid-state, potentiometric, miniaturized sensors for pH and potassium was developed to be introduced into the stomach or other sectors of the digestive tract by means of flexible endoscopy. These sensors perform continuous and simultaneous measurement of extracellular pH and potassium. This detection seeks to sense ischemia in the gastric mucosa inside the stomach, an event indicative of local microvascular perfusion and tissue oxygenation status. Our array is proposed as a medical tool to identify the occurrence of the ischemia after gastrointestinal or gastroesophageal anastomosis. The stability and feasibility of the miniaturized working and reference electrodes integrated in the array were studied under in vitro conditions, and the behavior of the potassium and pH ion-selective membranes were optimized to work under acidic gastric conditions with high concentrations of HCl. The array was tested in vivo in pigs to measure the ischemia produced by clamping the blood flow into the stomach. Our results indicate that ischemic and reperfusion states can be sensed in vivo and that information on tissue damage can be collected by this sensor array. The device described here provides a miniaturized, inexpensive, and mass producible sensor array for detecting local ischemia caused by unfavorable anastomotic perfusion and will thus contribute to preventing anastomotic leakage and failure caused by tissue necrosis.