Ruediger L. Prosst

The OTSC® Proctology clip system for anal fistula closure: first prospective clinical data.

Abstract Introduction: Anorectal fistulas represent a troublesome condition for both patient and surgeon. The OTSC® Proctology clip system is a new device for transanal anorectal fistula closure. Material and methods: The OTSC® Proctology system was evaluated in a prospective clinical study undertaken in two surgical proctological centers. Ten patients (three women, seven men; median age 55 years, range 25-73 years) with nine transsphincteric and one suprasphincteric fistulas were enrolled into the study. Results: The median operation time was 30 minutes (range 20-45 minutes). There were no intraoperative technical or surgical complications. Postoperatively, no patient reported intolerable discomfort, immoderate pain or foreign body sensation in the anal region. At follow-up examination six months after surgery, nine out of ten patients had no clinical signs or symptoms of their previous fistula and were considered as healed (success rate 90%). In one patient persistency of the fistula was noted due to spontaneous early clip detachment on the third postoperative day. Discussion: These first data demonstrate the efficacy of the OTSC® Proctology system in the treatment of anal fistulas. Currently, more patients were enrolled into this prospective study to allow further evaluation of this new device and to assess its future role in relation to established surgical strategies for anorectal fistulas.

The OTSC® Proctology clip system for anorectal fistula closure: the 'anal fistula claw': case report.

Abstract Surgical treatment of high or complex anal fistulas often renders unsatisfying results. This is the report of the first successful closure of such anal fistula using a special Nitinol clip and applicator, the OTSC® Proctology system (Ovesco AG, Tuebingen, Germany): A 54-year old female patient was suffering from a high transsphincteric anal fistula. After seton drainage of the fistula for ten weeks, the fistula track was debrided using a special fistula brush. After transanal clip release from the applicator, the internal fistula opening was adequately closed by the clip. Eight months after clip closure the fistula had healed and the clip was removed using the OTSC® Proctology Clip Cutter. Fistula closure using the OTSC® Proctology system represents a promising sphincter-preserving minimally invasive procedure.

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.

Comment on: Easy clip to treat anal fistula tracts: a word of caution by M. Gautier et al.

Dear Editor: We would like to comment on the paper by Gauthier and colleagues on OTSC clipping in the treatment of anal fistula. The authors present their experience collected at multiple sites with this new surgical procedure, coming to negative conclusions about its effectiveness. We appreciate the report. Having been the developers of this procedure and in the knowledge of data published by our and other groups about this technique, we however cannot agree with the way Gauthier et al. present their experience. First of all, there is some lack of definition in fundamental terminology. The title of the paper and the conclusions drawn refer to anal fistula. However, 41 % (7/17) of patients had recto-vaginal fistulae, which is a different disease entity concerning etiology, course, and treatment. Success rates of recto-vaginal fistula surgery are significantly lower when compared to anal fistulae: for local closure techniques, including advancement flaps, the literature reports success rates of one third and even less. The case group presented by Gauthier is suffering from a strong selection bias, as the authors point out themselves. Besides the 41 % of recto-vaginal cases, 35 % (6/17) had inflammatory bowel disease. It is known from literature that up to two thirds of Crohn’s patients who undergo fistula surgery have poor wound healing and persistent complications, due to the underlying inflammatory condition. Thus, the complication rate and profile reported by Gauthier is in the range of what needs to be expected in the studied patient population with 64 % (11/17) of patients having recto-vaginal fistula location, Crohn’s disease, or both. It also remains unclear whether the patients had prior surgery and a recurrent fistula before treated with OTSC, which would be relevant information to judge the procedural success rate. Only 35 % (6/17) of the patients presented apparently suffered from typical crytoglandular anal fistula; the rest were of other etiology. Thus, the patient group studied does not represent the core of the indication spectrum for OTSC clipping but is rather at the extreme margin of what this procedure is indicated for. The rationale for such a clinical investigation as presented here remains unclear. As it is a common scientific practice, new procedures shall be evaluated in the core of their indication range first and not in extreme cases which are borderline indications. The authors discuss a clip-induced devascularization of the captured tissue with consecutive persistency of the fistula. However, literature about clip application on evenmore fragile tissue, such as bowel, has not reported on such an effect. The OTSC clip is widely used in flexible endoscopy since years. Research by numerous independent authors has demonstrated that the clip geometry allows sufficient microperfusion between the teeth of the closed clip to prevent ischemia. The most striking problem of the case series presented by Gauthier is the enormous rate of primary technical failure, meaning unsuccessful primary closure of the fistula orifice with the OTSC clip. Seventy-six percent of patients (13/17) are reported to have had continuing discharge from the fistula. This means that the clip has apparently not been properly placed during surgery or the orifice may have been too large or anatomically unsuitable to be closed by clips. The reported clinical success rate of only 12 % must be seen in the context This article is a commentary to http://dx.doi.org/10.1007/s00384-015-2146-5

A new serrated snare for improved tissue capture during endoscopic snare resection

Abstract Endoscopic snare resection of gastrointestinal polyps and neoplasm is a standard procedure in interventional endoscopy. Due to technical and procedural improvements the removal of large sessile polyps can be achieved by endoscopic mucosal resection either in one single specimen or by piecemeal resection. In this experimental study a new snare with special teeth attached to the distal part of the wire loop was evaluated and compared to a conventional snare. Seventy artificial sessile tumors were created in a standardized manner in a porcine ex vivo colon. Thirty-five polyps were resected with the new serrated snare, whilst the other 35 polyps were removed using an identical snare without teeth. The weight measurement of the resected polyps showed that when using the new serrated snare 31% more tissue could be removed with a single snare resection in comparison with the conventional snare without teeth (mean 454 mg vs. 347 mg, ±202 mg vs. ±165 mg). The teeth obviously increased the effectiveness of snare resection by avoiding the accidental loss of entrapped tissue from the loop. The new snare hopes to faciliate the removal of flat polyps and to reduce the number of specimens during piecemeal resection to a minimum, allowing a better histopathological assessment.

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.

Minimally invasive surgical clip closure of anorectal fistulas: current status of OTSC Proctology

Abstract OTSC Proctology is a minimally invasive sphincter-preserving technique for the surgical treatment of anorectal fistulas. It is based on a super-elastic Nitinol clip which closes the internal fistula opening to allow healing of the fistula tract. A systematic search of the literature was undertaken to identify publications about OTSC Proctology. All studies and reports identified were reviewed and evaluated to determine the feasibility, efficacy and safety of clip surgery. The assessment of all available studies with a total of more than 200 surgical cases strongly suggests that the clip procedure is safe and effective with a low rate of complications. The technique rendered convincing short and long term results with an overall healing rate of approximately 63%. Best results were achieved when OTSC Proctology was used as first-line treatment (healing rate 74%) and for cryptoglandular fistulas (healing rate 64%). However, its future clinical role for IBD-associated recurrent and anorecto-vaginal fistulas remains to be determined, due to a relatively low number of these patients in the evaluated studies. OTSC Proctology is part of the novel armamentarium for the treatment for anorectal fistulas, which is based on high-technology devices. They can be repeatedly used and even combined without causing irreversible sphincter damage.

A randomized comparative trial of OTSC and Padlock for upper GI hemostasis in a standardized experimental setting

Abstract Introduction: Upper gastrointestinal bleeding (UGIB) is the key emergency situation in clinical endoscopy and is traditionally treated with injection, thermal or through the scope clipping therapy. Mortality rates are in the range of 8–10% and demand new treatment approaches. The Over-The-Scope Clip (OTSC®) has been described as a very effective hemostatic device in UGIB. We compared OTSC with the Padlock™ device in an established pre-clinical setting. Material and methods: Our test-bed consisted of the biohybrid EASIE model using soft silicone tubes, tunneled into the gastric wall and surfacing at a mucosa defect, representing the bleeding site. After successful deployment of the OTSC and Padlock devices on the spurting ulcer bleed (Forrest Ia) the vessel tubes were pressurized with a manometer to 120 mmHg. Tight closure at this pressure was defined as successful hemostasis (primary endpoint). N = 11 procedures were done with each device. Statistical testing was done using Fisher’s exact test. Sample size was adjusted to an assumed α-error of 5% (two-sided test) and a power of 80%. Results: Technically correct placement of the respective hemostatic device was achieved in all procedures. A statistically significant difference was found in the primary endpoint. In OTSC the success proportion was 100%; 11/11 (95% KI 74.1% to 100%); in Padlock it was 0%; 0/11 (95% KI 0%–25.8%). This means that no bleeding was stopped by Padlock. The mean value of perfusion pressure resistance was 300 mmHg (cut-off) for OTSC and 9.2 ± 8.4 mmHg for Padlock. Discussion: Our data on hemostatic function of OTSC coincide with the clinical literature and earlier pre-clinical studies in the EASIE model, which is widely accepted as a realistic and effective simulation system for clinical conditions. The inability of Padlock to stop hemorrhage may be due to design differences and, thus, its limitation in providing tight sealing of the clipped tissue. Conclusion: Different types of endoscope-tip mounted clips have different performances. OTSC consistently stops simulated spurting bleeding, Padlock fails to do so. These differences are statistically significant.

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.

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

BackgroundAn 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.MethodsA 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.ResultsWith 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.ConclusionsThe HemoPill is a valuable tool to detect an acute upper gastrointestinal bleeding event without the need of endoscopy.