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 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.

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.

DC current pulses for OTSC clip fragmentation: technology and experimental study.

BACKGROUND: The OTSC clip is used in endoscopic management of gastrointestinal lesions. In rare cases, the removal of the OTSC clip might be desirable. The objective of the study is to investigate feasibility, efficacy, and safety of a novel endoscopic instrument system for removal of the OTSC clip. METHODS: The study series has been conducted in a porcine model. Clip removal is performed with a prototype instrumentation that is designed to locally melt the clip by applying an electrical current pulse onto the clip structure. This system has been evaluated in an animal study (n = 10) in a pig model. A cap prototype with an elongated sleeve has been used for extraction of the OTSC clip fragments. RESULTS: 23 of 24 implanted OTSC clips were successfully opened by applying in a total of 74 current pulses. Superficial mucosal coagulation marks were observed in 14 of the 24 application sites. No other findings such as hemorrhage, deep thermal wall lesions, or perforation were observed. CONCLUSIONS: The study confirms the effectiveness and safety of the proposed endoscopic removal technique. Safe extraction of the clip fragments was feasible with an elongated sleeve at the distal cap. Limitations of the methods are the animal model and the experimental nature of the prototype instrumentation.

Retention of endoscopic capsules in diverticula: Literature review of a capsule endoscopy rarity.

Background and study aims This review aimed to provide an updated and comprehensive review of capsule retention within diverticula, shedding light on the characteristics and management of this rare event in capsule endoscopy. Methods A systematic literature search was conducted across multiple databases. All observational studies that reported capsule retention in a diverticulum among complication and outcomes, as well as case reports and series, were included. Manual cross-checking of references was also performed. Two extractors performed abstract and full-text reviews, as well as data-extraction. Results We found 167 references from Pubmed, Embase, and Web Of Science. Sixty-five duplicates were removed and another 71 references were excluded. Crosschecking of references found additional two articles. In total, 32 articles were included, resulting in a total of 34 cases of retained capsules in diverticula. The median age was 69 and the majority of the patients were male (76.5%). The most common retention occurred in Meckel's diverticulum (32.4%) followed by Zenker's diverticulum (20.6%). Investigation of capsule retention was done with x-ray (50%) and computed tomography (CT) scan (44.1%). Seventeen cases (50%) were asymptomatic. Resolution of the retention happened with endoscopy (35.3%) and surgical management (32.4%), as well as self-resolution (20.6%). Conclusions Due to the small number of cases, diverticula are not a risk factor for incomplete capsule endoscopy examination. It affects mainly elderly, male, asymptomatic patients, and typically is diagnosed with x-rays and CT scans. The most common type is Meckel's diverticulum, and endoscopy is the primary management. Capsule endoscopy retentions are extremely rare, with only 34 cases reported since the technology's introduction.

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.

Artificial tactile feedback can significantly improve tissue examination through remote palpation.

BACKGROUND: In laparoscopy, impaired feedback information from the operation site and reduced instrument dexterity lead to high demands on surgeons' skill and experience. Pre-clinical studies have shown that artificial tactile feedback (ATF) could significantly improve the quality of tactile feedback information. Additional information about interaction effects of tissue features when using ATF as well as related detection thresholds would be valuable for drawing conclusions on possible clinical application scenarios. OBJECTIVE: To identify surgical procedures in laparoscopy that could benefit from ATF in tissue examination through remote palpation. METHODS: We have developed a laparoscopic grasper capable of providing ATF by measuring the pressure distribution on one forceps jaw with a tactile sensor array. The data was presented graphically on the endoscopic screen. We conducted a study among surgeons and non-surgeons, comparing the capability to detect hidden objects through remote palpation with and without ATF. The data were analyzed using repeated-measures multiple analysis of variance (MANOVA) in two designs. RESULTS: ATF could enhance feedback information with significant positive effects on accuracy, speed, the reduction of the number of grasps, and user confidence. The positive effect of ATF turned out to be especially strong if hidden objects were either hard and too small or large and too soft to be recognized by remote palpation without ATF. CONCLUSIONS: Our study contributes to the discussion on promising application scenarios of ATF-enhanced instrumentation in laparoscopic surgery. Based on our study results, such instrumentation may be valuable for detection and examination of hidden bodies or structures through remote palpation.

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.

Feasibility proof of a legged locomotion capsule for the GI tract.

BACKGROUND: A colonoscopy and a gastroscopy are the most important screening measures for malignant diseases in the GI tract. One of the main limitations is the lack of patient adherence to come in for a flexible endoscopy, especially in asymptomatic conditions. OBJECTIVE: The feasibility proof of a new generation of endoscopic capsules based on a novel propelling mechanism that features electromechanical legs. DESIGN: Teleoperated endoscopic 8-legged capsule. SETTING: Scuola Superiore Sant'Anna, Pisa, Italy, and novineon Healthcare Technology Partners GmbH, Tübingen, Germany. MAIN OUTCOME MEASUREMENTS: Successful locomotion in a lower-GI tract (LGI) phantom model and in a porcine colon. RESULTS: The testing session was organized into repetitive ex vivo trials and in vivo tests. The repetitive tests were performed for collecting reproducible data in various small series of individual experiments in standardized conditions, thus defining the best locomotion parameters. In vivo tests were performed in a porcine colon: the capsule, inserted transanally, traveled upward in the oral direction for 15 cm in about 5 minutes, against peristalsis. LIMITATIONS: The current version of the capsule travels curves by bouncing back from the wall and following step by step the direction of the curved bowel. Steering mechanisms are not yet implemented. CONCLUSIONS: This study shows the systematic development and medical assessment of an imaging capsule with self-propelling abilities. A full colonic passage was successfully demonstrated in the ex vivo phantom model. A net movement in in vivo tests has been achieved, thus giving a feasibility proof of the legged locomotion as a possible solution to the problem of self-locomoting endoscopic devices in the LGI.

An innovative robotic platform for magnetically-driven painless colonoscopy.

Colorectal cancer (CRC) represents a significant medical threat with a dramatic impact on the healthcare system with around 1.3 million patients worldwide, causing more than 700 thousand deaths annually. A key-aspect to successful and cost-effective disease management is represented by the early detection of CRC at asymptomatic stage. For this reason, population screening is highly recommended for patients older than 50 years or at high risk for familiarity. Currently, the standard endoscopic techniques do not meet this need. In recent years, innovative endoscopic robotic techniques and active locomotion devices have been developed as alternatives to conventional colonoscopy. The magnetically-driven robotic platform, presented by the authors, is conceived to perform less invasive and more comfortable colonoscopy with the aim to promote screening campaigns for detection of early colorectal neoplasm.

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.

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.

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.

Review on aspects of artificial tactile feedback in laparoscopic surgery.

Since direct manual tissue palpation is not possible in laparoscopic surgery, feedback information on tactile tissue properties is considerably diminished. Restoring part of the surgeon's sense of touch through devices capable of providing artificial tactile feedback (ATF) is an active field of applied research and development. Despite more than two decades of research, technical development of such devices is still basic, and pre-clinical as well as clinical experience is limited. This article provides an overview of the technological aspects of ATF in laparoscopic surgery, gives background information on principles of human perception of related feedback information, and reviews current research attempts in the field of ATF systems in laparoscopic surgery, broken down into three main system components: tactile sensor, display, and data processing. Tactile sensors have been developed to measure tissue compliance, reveal hidden structures or foreign bodies in tissue through measurement of pressure distribution, and to identify and locate arteries by detecting their pulsation. Furthermore, different solutions for presenting tactile data to the surgeon have been developed. Visual and auditory displays are easy to implement into the operating room equipment, while tactile displays still suffer from difficulties concerning their performance and requirements for clinical usability. The role of the data processing system as the linking component in an artificial tactile feedback system has been identified as crucial for effectiveness of the system and easy reception of tactile data by the surgeon. The investigations on theoretical and technological foundations of ATF have led to an extensive database in recent years. An application-driven development approach will likely be a driving factor in the future evolution of this field.

Microtechnologies in medicine: an overview.

Microsystems technology (MST) has become a significant enabler of novel medical devices and implants over the last years. Typical examples are MST units in cardiac rhythm management devices or in hearing implants. A classification of medical MST applications can be made according to their relationship with the anatomy that is based on the kind and duration of interaction with the human body: Class 1: Extra-corporeal devices such as telemetric health monitoring systems or point of care testing systems. Class 2: Intra-corporeal devices such as intelligent surgical instruments. Class 3: Temporarily incorporated or ingested devices, such as telemetric endoscopes. Class 4: Long-term implantable devices such as telemetric implants. Medical applications of MST are growing at double-digit compounded growth rates, leading to a forecasted global market volume of over USD 1 billion in 2006 or 2007, making MST devices a relevant segment of the medical technology market. The clinical foundation for promoting the use of MST in medicine is mainly based on the significant potential of MST to enable products that improve early disease detection and the monitoring of chronic illnesses. This refers to a number of the most important health problems such as cardiovascular disease, hypertension, diabetes and cancer, to name just a few. More recently microrobotics has become a relevant research area for enabling the atraumatic transport of MST-enhanced diagnostic and therapeutic devices inside the human body.

Artificial tactile sensing in minimally invasive surgery - a new technical approach.

The loss of tactile sensation is a commonly known drawback of minimally invasive surgery (MIS). Since the advent of MIS, research activities in providing tactile information to the surgeon are still ongoing, in order to improve patient safety and to extend the indications for MIS. We have designed a tactile sensor system comprising a tactile laparoscopic grasper for surgical palpation. For this purpose, we developed a novel tactile sensor technology which allows the manufacturing of an integrated sensor array within an acceptable price range. The array was integrated into the jaws of a 10mm laparoscopic grasper. The tactile data are transferred wirelessly via Bluetooth and are presented visually to the surgeon. The goal was to be able to obtain information about the shape and consistency of tissue structures by gently compressing the tissue between the jaws of the tactile instrument and thus to be able to recognize and assess anatomical or pathological structures, even if they are hidden in the tissue. With a prototype of the tactile sensor system we have conducted bench-tests as well as in-vitro and in-vivo experiments. The system proved feasibility in an experimental environment, it was easy to use, and the novel tactile sensor array was applicable for both palpation and grasping manoeuvres with forces of up to 60N. The tactile data turned out to be a useful supplement to the minimal amount of haptic feedback that is provided by current endoscopic instruments and the endoscopic image under certain conditions.