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.

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.

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.

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.

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.

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.

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.

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.

25 years of SMIT: the past, the present, and the future of minimally invasive therapy.

A quarter of a century has passed since the Society of Minimally Invasive Therapy (SMIT) was founded in 1989 with the aim to provide a platform to promote the development of minimally invasive therapy and the new instruments and devices needed to carry out the new surgical techniques. Both the founder of the society, British urologist John EA Wickham, and the German surgeon Gerhard F Buess, who was one of the leading members from the beginning, conceived SMIT as an interdisciplinary forum to promote the cooperation between physicians from various surgical specialties, but also medical engineers, resp. medical device manufacturers, whose expertise was needed to build the instruments that had to be developed to carry out the new concept of surgery. In this paper we outline the history of SMIT over the past 25 years in order to highlight both the ideas behind the society and the dedication of the people who shaped it.

European research on wireless endoscopy--the VECTOR project.

Within the European VECTOR project, various technologies to enhance the current field of capsule endoscopy towards screening of colorectal cancers and its precursors, and enhanced diagnostic and therapeutic functionalities have been developed. Among others, this includes technologies for active locomotion, wireless therapy and detection of gastrointestinal bleeding. The VECTOR project has contributed to the trend to develop novel procedures for improved diagnosis and treatment of gastrointestinal diseases.

Performance of the OTSC System in the endoscopic closure of iatrogenic gastrointestinal perforations: a systematic review.

BACKGROUND: Reliable closure is a prerequisite for conventional and innovative endoscopic procedures, such as NOTES. The purpose of this study is the systematic evaluation of the procedural and clinical success rates in closure of iatrogenic gastrointestinal perforations and acute anastomotic leaks by means of the over-the-scope-clip system (OTSC(®)). DESIGN: PubMed and other sources were searched systematically for clinical and preclinical research on the evaluation of the OTSC System for closure of gastrointestinal perforations and leaks. Appraisal of studies for inclusion and data extraction was performed independently by two reviewers using an a priori determined data extraction grid. Major endpoints to be extracted were data on procedural success (successful clip application) and clinical access (durable closure of defect without secondary adjunct therapy). RESULTS: A total of 17 clinical research articles/abstracts and 22 preclinical research articles/abstracts were identified. The examined clinical studies comprised case series and clinical single-arm studies. The reviewed studies revealed a consistently high mean rate of procedural success of 80-100 % and durable clinical success of 57-100 %. An identified major drawback preventing successful clip application was occurrence of fibrotic or inflamed lesion edges. Usage of the OTSC System was accompanied by neither major clip-related nor application-related complication. In experimental settings, closure of larger perforations and gastric access sites of NOTES or endoscopic full-thickness resection were achieved with high rates of success. CONCLUSIONS: Because randomized, clinical trials are not available in this field of indication, the evaluation is based on small case series. Nevertheless, by pooling all experience gained, we conclude that endoscopic closure of iatrogenic gastrointestinal perforations and acute anastomotic leaks by means of the OTSC System is a safe and effective method.

The HemoCop Telemetric Sensor System: technology and results of in-vivo assessment.

Upper gastrointestinal bleeding is considered the most frequent emergency in endoscopy units. Decisive for successful treatment of acute upper gastrointestinal bleeding is a timely recognition. We have developed a telemetric implant containing a novel optical sensor principle able to detect the presence of blood in the lumen of the GI tract. In-vivo experiments demonstrated the possibility to detect bleeding in situ and to send an alert signal to an extracorporeal receiver.

Performance of the OTSC System in the endoscopic closure of gastrointestinal fistulae--a meta-analysis.

BACKGROUND: Conventional endoscopic treatment options for closure of gastrointestinal fistulae are impaired by several limitations and therefore yield high rates of recurrence. Aim of the study is the evaluation of the primary-technical and secondary-clinical success rates in closure of gastrointestinal fistulae by means of the OTSC System. DESIGN/METHODS: The database Medline was systematically searched for primary research on the evaluation of the OTSC System in closure of gastrointestinal fistulae. Appraisal of studies for inclusion and data extraction were performed independently by two reviewers using an a priori determined data extraction grid. RESULTS: A total of 19 primary research articles were identified. The examined studies comprised case reports as well as case series and clinical single-arm studies (n = 7) with a limited number of participants. Reviewed studies revealed a high rate of procedural success (mean 84.6%; 95% confidence interval 66.6 to 93.8%) and durable clinical success (mean 69.0%; 95% confidence interval 51.8 to 82.2%). Failed attempts and incomplete closures were mainly ascribed to the challenging effort of treating highly fibrotic chronic fistulae. CONCLUSION: Endoscopic closure of gastrointestinal fistulae by means of the OTSC System is a safe and effective method.