The over-the-scope grasper (OTSG).

BACKGROUND : Endoscopic removal of foreign bodies, coagulated blood, or necrotic debris is sometimes challenging and time-consuming, partly because of inadequate endoscopic instruments. Therefore, new devices are needed to overcome the current limitations. METHODS : The over-the-scope grasper (OTSG) is a new grasping tool that can be attached to any standard gastroscope. It has been developed for endoscopic removal of larger particles. We present retrospective data on five patients who were treated using the device for various indications, including necrosectomy, bolus impaction, and removal of blood clots. RESULTS : In two patients, the OTSG was used through a lumen-apposing metal stent for direct endoscopic necrosectomy after severe pancreatitis. The other patients had a massive blood clot in the esophagus after endoscopic submucosal dissection, or aphagia due to large meat chunks clogging the esophagus. The OTSG was used with technical success in all of the patients and without any procedure-associated complications. CONCLUSION : The OTSG appears to be a useful device for endoscopic removal of larger particles, blood clots, or necrotic debris. Preliminary experience shows that the device is effective and easy to use.

EMR + with the AWC improves endoscopic resection speed compared to ESD: a porcine ex-vivo pilot study.

INTRODUCTION: To improve resection speed and to reach higher en bloc resection rates in lesions ≥ 2 cm, a novel grasp and snare EMR technique termed "EMR+", accomplished by an additional working channel (AWC), was developed. Its use compared to endoscopic submucosal dissection (ESD) is evaluated for the first time. MATERIAL AND METHODS: We prospectively conducted a randomized pre-clinical ex-vivo pilot study in explanted porcine stomachs for the comparison of EMR + with classical ESD of mucosal-based lesions. Prior to intervention, we set flat lesions with a standardized size of 3 × 3 cm. RESULTS: The median time of procedure was significantly shorter in the EMR + group (median 10.5 min, range 4.4-24 min) than in the ESD group (median 32 min, range 14-61.6 min, p < .0001). The rate of en bloc resection was significantly lower in the EMR + group (38 % vs. 95 %) (p < .0001). Nevertheless, an improvement in the learning curve for EMR + was achieved after the first 12 procedures, with a subsequent en bloc resection rate of 100 %. CONCLUSIONS: EMR + could improve the efficiency of mucosal resection procedures. Initial experience demonstrates a higher and satisfactory en bloc resection rate after going through the learning curve of EMR+.

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.

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.

Endoluminal full-thickness resection of GI lesions: a new device and technique.

Full-thickness resection techniques are of growing interest in the field of endoscopic removal of tumors or their precursors in the digestive tract. A new dedicated full-thickness resection device has been developed based on the combination of the OTSC clip, an enlarged resection cap and an integrated snare. The device prototype allows combined resection of all gastrointestinal organ wall layers in one maneuver, up to a size of 3 x 3 cm. The device has been pre-clinically tested to demonstrate feasibility of full-thickness resection in the colon. Two clinical cases have been performed successfully to date.

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.

Implantable endoscopic gastric bypass - device and experimental procedure.

Malabsorptive bariatric surgery is an effective treatment option for morbid obesity, but may be associated with complications and side effects. We have developed a new experimental approach to creating a gastric bypass through an intraluminal access. The goal is to reduce postoperative complications and to reduce mid-term side-effects of malabsorptive bypass food passage and to allow easy reversion of the procedure. The new procedure is based on an implantable gastric bypass device, installed by combined transoral flexible and minimally invasive abdominal access. The newly developed device and procedure were studied in a pilot experimental trial in the porcine animal model (n=8). Endpoints were the feasibility of the technical procedure, the ability of the animal to eat and digest food, the implant functionality over the survival period and the absence of major complications over a short-term follow-up (one week). The procedure was technically successful in all eight animals. Animals were able to take in food and water till sacrifice. Four animals had major complications (one abdominal wall dehiscence, one invagination ileus of the small bowel, one dehiscence of the gastro-jejunal anastomosis and one myocardial infarction) and did not complete follow-up. In two cases migration of the device into the stomach was observed. The difference between our experimental technique and the gold standard surgical methods for gastric bypass consists of the endoluminal approach by implanting an intraluminal gastric bypass device. This concept avoids gastric transsection and an additional anastomosis and enables an adjustable food passage between the bypass and the natural duodenal passage. Further long-term follow-up studies are required.

[Experimental study on a new method for colonoscopic closure of large-bowel perforations with the OTSC clip]. / Experimentelle Untersuchung zu einem neuen Verfahren für den koloskopischen Verschluss von Dickdarmperforationen mit dem OTSC-clip.

Iatrogenic perforation of the colon during interventional endoscopic procedures, e.g., mucosectomy, is a problematic complication, as safe treatment often requires surgical repair. Iatrogenic perforation of the colon is indeed a rare complication; however, given the increasing case numbers in interventional endoscopy it is of considerable practical relevance. The closure of perforations can be achieved with conventional endoscopic clips; however, these working channel based clips are often too small to close a perforation securely. Therefore, we have developed a novel endoscopic clipping system that can be attached to the tip of the endoscope. This over-the-scope-clip system (OTSC), made of Nitinol, was tested in an experimental trial (domestic pig, 50-60 kg) for its applicability for perforation closure. In acute experiments, tight endoscopic closure of 10 perforations in five animals was demonstrated; perforations were made through repeat biopsy. In three further animals, the postoperative course was studied over a period of 2 weeks. Peritonitis was not found in any of these animals. The local healing result at the site of implantation was good. Clips were present 2 weeks after the procedure. In this experimental study, the OTSC clip system was found to be a simple and secure method of iatrogenic colon perforation closure.

Feasibility study for secure closure of natural orifice transluminal endoscopic surgery gastrotomies by using over-the-scope clips.

BACKGROUND: The secure sealing of natural orifice transluminal endoscopic surgery (NOTES) approaches to the abdominal cavity is a problem that has not been solved. The feasibility of closing iatrogenic endoscopic GI-tract perforations by using a new over-the-scope clip was recently described. OBJECTIVE: To demonstrate the feasibility of endoscopic closure of transgastric NOTES approaches with a novel clip system. DESIGN: Acute nonsurvival animal study (porcine model; n = 9). INTERVENTIONS: Transgastric approaches were performed by using a needle-knife and balloon dilation. After abdominopelvic exploration, the transgastric approaches were closed by using the OTSC clipping system with suction. The procedure was performed under laparoscopic visualization. RESULTS: Gastrotomy lesions could primarily be closed in 8 cases. However, the laparoscopic control indicated that the clip adaptation of the wound margins was not completely airtight under maximum insufflation of the stomach in 4 of 9 cases. LIMITATION: Nonsurvival animal study. CONCLUSIONS: Sufficient closure of transgastric NOTES approaches is feasible when using the OTSC system. When considering our clinical experience, the OTSC system was shown to be an uncomplicated and secure sealing technique in human beings.

New developments for endoscopic hollow organ closure in prospective of NOTES.

The closure of the gastrotomy in Natural Orifice Endoscopic Surgery (NOTES) is a prerequisite for transgastric endoscopic procedures in the abdominal cavity. Different techniques have been proposed and are under experimental or early clinical investigation. These include the use of conventional endoscopic clips, newly designed clips or T-BARS in different shapes or more complicated devices such as linear endoscopic staplers and septal occluders, originally used for the treatment of cardiac septal defects. We describe here a further alternative of endoscopic organ closure in NOTES, using the OTSC, a novel type of clip attached to the tip of the endoscope. The OTSC clip as a CE-marked device is widely used clinically for various endoscopic procedures, such as the treatment of gastrointestinal bleeding and iatrogenic defects of the digestive tract, e.g. colonic perforations after endoscopic interventions. Now an enlarged version of the OTSC clip can be applied for the closure of transluminal access to the abdominal cavity and is currently being evaluated for use in NOTES. In animal tests we could demonstrate the relatively easy achievement of a full thickness closure of the gastric wall after NOTES in the experimental model. The current data base on OTSC and on other techniques proposed for organ closure after NOTES does not yet allow determining clear advantages or disadvantages of the different options. We believe the hollow organ defect closure now represents the most important issue to decode whether or not we are going to proceed with NOTES. Ongoing surviving animal labs will give us indications on how to proceed.

The OTSC clip for endoscopic organ closure in NOTES: device and technique.

The closure of the gastrotomy in Natural Orifice Transluminal Endoscopic Surgery (NOTES) is a prerequisite for transgastric endoscopic procedures in the abdominal cavity. Different techniques have been proposed and are under experimental or early clinical investigation. We describe the technique of using an over-the-scope-clip system (OTSC), made of super-elastic Nitinol and a specially designed tissue-approximating double jaw endoscopic grasper for gastric closure. The OTSC is a clipping system mounted at the tip of the endoscope and is used for the treatment of gastrointestinal bleeding or gastrointestinal organ perforations. An enlarged version of the OTSC is now under investigation for NOTES. The closure procedure consists of two steps. First the margins of the perforation are approximated by means of an endoscopic grasper that has two mobile and one fixed jaw, thus providing two independent tissue grasping areas. Each half of this twin grasper is used to grasp one side of the perforation wound margins. Then the margins are approximated and pulled towards the OTSC cap at the tip of the scope. Then the clip is released and the access hole is closed by compression. The OTSC clip can be applied for organ closure in NOTES in experimental studies. The technique allows closing the access site from inside the gastric cavity without leaving material on the peritoneal surface of the organ.

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.

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.