Chi-Nghia Ho

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.

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

Abstract 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.

[Experimental study on a new method for colonoscopic closure of large-bowel perforations with the OTSC clip].

Zusammenfassung Die iatrogene Perforation des Kolons im Rahmen endoskopisch-interventioneller Eingriffe, wie z.B. der Mucosektomie, ist eine problematische Komplikation, da sie zu ihrer sicheren Behandlung nicht selten eine Operation erforderlich macht. Zwar sind iatrogene Kolonperforationen relativ selten, bei Ansteigen der Fallzahlen koloskopischer Eingriffe jedoch von einiger praktischer Bedeutung. Der Verschluss von Perforationen kann mit konventionellen endoskopischen Clips erfolgreich durchgeführt werden, oft erweisen sich diese durch den Arbeitskanal des Endoskops applizierbaren Clips aber als zu klein, um eine Perforation sicher zu verschließen. Wir haben daher ein neuartiges endoskopisches Clipsystem entwickelt, das auf die Spitze des Endoskops aufgesteckt wird. Dieses Over the scope clip-System (OTSC®) aus Nitinol wurde hier in einer experimentellen Studie auf seine Anwendbarkeit zum Perforationsverschluss beim Versuchstier (Hausschwein, 50–60 kg) untersucht. In Akutversuchen konnte bei zehn Perforationen in fünf Versuchstieren ein dichter endoskopischer Verschluss einer durch wiederholte Biopsie erzeugten Perforation gezeigt werden. Bei weiteren drei Versuchstieren wurde der postoperative Heilungsverlauf nach Clipimplantation über einen Zeitraum von 2 Wochen untersucht. Bei keinem Tier trat eine Peritonitis auf. Das lokale Heilungsergebnis im Bereich der Implantationstelle war gut, die Clips waren nach zwei Wochen noch vor Ort. Das OTSC®-Clipsystem stellt in der experimentellen Anwendung eine einfache und sichere Methode zum Verschluss iatrogener Kolonperforationen dar. Abstract 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.

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.

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

BackgroundIn 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.ObjectiveTo identify surgical procedures in laparoscopy that could benefit from ATF in tissue examination through remote palpation.MethodsWe 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.ResultsATF 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.ConclusionsOur 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.

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

Abstract 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.

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.