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.

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

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.

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.

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.

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

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.

Fluorescence-guided minimally invasive parathyroidectomy: clinical experience with a novel intraoperative detection technique for parathyroid glands.

BACKGROUND: Detection of normal and pathologic parathyroid glands often is difficult due to their variability in number and location. We have implemented photosensitizer-induced fluorescence for the routine intraoperative identification of parathyroids for the surgical treatment of hyperparathyroidism. METHODS: From 2004 to 2007, 25 patients suffering from primary and secondary hyperparathyroidism underwent minimally invasive videoscopic-assisted parathyroidectomy after oral photosensitization with aminolevulinic acid (ALA). RESULTS: Fluorescence was sufficiently strong in 48% of patients to aid faster detection of the glands in situ. In an additional 44%, the fluorescence behavior supported the identification of the glands in situ and after excision, yielding a total of 92% of glands whose identity could be confirmed by the fluorescence technique. CONCLUSIONS: Fluorescence-guided minimally invasive parathyroidectomy is technically feasible and may support the surgeon in detecting and confirming the parathyroid glands. As the fluorescence method requires only moderate additional technical efforts and clinical expenditure, it is a valuable add-on component in parathyroid surgery to facilitate the operation.

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

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.

Fluorescence-guided minimally invasive parathyroidectomy: a novel surgical therapy for secondary hyperparathyroidism.

Secondary hyperparathyroidism (SHPT) is a severe and frequent complication in patients with advanced chronic kidney disease, characterized by hyperplasia of all parathyroid glands and elevated serum parathyroid hormone levels. When surgery is required to prevent cardiovascular consequences, bone pain, osteoporosis, or even soft-tissue calcifications, detection of the enlarged glands often can be difficult because of their variability in number and location. A novel surgical technique, fluorescence-guided minimally invasive parathyroidectomy, may facilitate intraoperative localization of parathyroid glands. A 52-year-old woman with SHPT underwent minimally invasive videoscopic-assisted parathyroidectomy after photosensitization with aminolevulinic acid (ALA): Under special fluorescence illumination by D-Light (Karl Storz Co, Tuttlingen, Germany), bilateral neck exploration was performed. All enlarged parathyroid glands were identified because of their ALA-induced intense red fluorescence. Such surrounding structures as thyroid, lymph nodes, and soft tissue remained nonfluorescent and could be distinguished easily from parathyroid glands. Total parathyroidectomy with autotransplantation into the sternocleidoid muscle was performed. In patients with SHPT, exploration of all parathyroid glands during surgery is mandatory. However, to date, there is no convincing technical aid for the surgeon to facilitate this procedure. The ALA-induced fluorescence technique represents an innovative visual detection method for intraoperative identification of parathyroid glands. The technique serves as an additional tool requiring only moderate technical and clinical expenditure.

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.

TST36 stapling for rectocele and hemorrhoidal prolapse - early results of the prospective German multicenter study.

Introduction: The aim of the study was to evaluate the safety and feasibility of stapled transanal procedures performed by a 36 mm stapling device, the so-called TST36 stapler. Methods: From September 2013 to June 2014 a prospective observational study was carried out by 8 proctology centers in Germany. The Cleveland Clinic Incontinence Score (CCIS) for incontinence and the Altomare ODS score were determined preoperatively. Follow-up examinations were performed after 14 days, one month and 6 months, at this time both scores were reevaluated. Results: 110 consecutive patients (71 women, 39 men) with a mean age of 59.7 years (±13.8 years) were included in the study. The eight participating institutes entered 3 to 31 patients each into the study. The indication for surgery was an advanced hemorrhoidal disease in 55 patients and ODS with rectal intussusception or rectocele in 55 patients. Mechanical problems with stapler introduction occurred in 22 cases (20%) and a partial stapleline dehiscence in 4 cases (3.6%). Additional stitches for bleeding from stapleline were necessary in 86 patients (78.2%). Reintervention was necessary for bleeding 7 times (6.3%). Severe complications during follow-up were stapleline dehiscence in one case and recurrent hemorrhoidal prolapse in 5 cases (4.5%). Altomare ODS score and CCIS improved significantly after surgery. Conclusions: Despite a notable complication rate during surgery and the postoperative period, the TST36 can be considered as an effective tool for low rectal stapling for anorectal prolapse causing hemorrhoids or obstructed defecation.

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.

Enhanced ALA-induced fluorescence in hyperparathyroidism.

INTRODUCTION: Intraoperative localization of parathyroid glands can be challenging especially in minimally invasive surgery. Fluorescence diagnosis using the photosensitizer aminolevulinic acid (ALA) has been described to identify normal parathyroid glands during experimental bilateral neck exploration. The present study evaluated fluorescence differences between hyperplastic and normal parathyroid glands as a precondition for a clinical application of the technique. MATERIALS AND METHODS: Polycystic kidney disease (PKD) rats with hyperparathyroidism due to hyperplastic parathyroid glands and Wistar rats with normal parathyroid glands were photosensitized by peritoneal lavage with ALA solution. After surgical exposure of thyroid and parathyroid glands the operative site was observed under blue light conditions using the d-light system to assess fluorescence characteristics of each tissue. Fluorescence intensities of parathyroid glands and surrounding thyroid tissue were measured by spectrometry. Parathyroid hormone in serum of the rats was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: Observation of the exposed thyroid site showed a subjectively stronger red fluorescence of the parathyroid glands in the PKD rats in comparison to the Wistar rats, whereas thyroid tissue appeared equally fluorescent. In the PKD animals, spectrometric fluorescence intensity was 10 times higher in the parathyroid glands than in the thyroid gland, whereas in the Wistar rats the ratio was 3.2:1. Fluorescence intensity in the parathyroid glands was more than twice in the PKD rats than in the Wistar rats, however slightly lower in the thyroid tissue. ELISA confirmed the pathophysiological change of a hyperparathyroidism with significantly increased serum levels of parathyroid hormone in the PKD rats. DISCUSSION: Hyperparathyroidism enhances ALA-induced fluorescence of the parathyroid glands. A combined surgical fluorescence strategy may justify a unilateral, minimally invasive approach in selected patients and serve to improve the capability of the surgeon to safely and efficiently manage parathyroid diseases.

Kinetics of intraoperative fluorescence diagnosis of parathyroid glands.

OBJECTIVE: Identification of parathyroid glands is often a challenge even for experienced surgeons. The feasibility and efficacy of fluorescence diagnosis for localization of parathyroids has already been proven in an experimental setting. In preparation for a clinical application of this technique in patients undergoing surgery for hyperparathyroidism, we evaluated the kinetics of fluorescence diagnosis. DESIGN AND METHODS: Fifty rats were randomized into eight groups with different photosensitization parameters using the photosensitizer aminolevulinic acid (ALA): a peritoneal lavage was performed with either 1.5 or 3.0% ALA solution and the induced photosensitization times varied from 0.5, 1 and 2 to 4 h. Under special fluorescence illumination, D-light, the exposed operative site with thyroid, parathyroid glands and neck muscles was examined. The identified parathyroid glands were studied according to fluorescence intensity by spectrometric measurement and compared with surrounding tissue. RESULTS: Photosensitizer accumulation in parathyroid glands, indirectly measured by spectrometry, was up to 3.2 times higher than in thyroid and 2.6 times higher than in muscle tissue (2 h photosensitization with 3.0% ALA). Using 1.5% ALA, the optimum fluorescence intensity and ratio/contrast was slightly lower (parathyroid-to-thyroid ratio x 3.0, parathyroid-to-muscle ratio x 1.9) but was reached earlier (1 h) and hence considered as the parameter of choice for a clinical application. CONCLUSIONS: In future clinical application, intraoperative fluorescence diagnosis is expected to increase the ease of identification of atypically located or supernumeric glands. In combination with preoperative diagnostics, this may result in reduced operation time and avoidance of persistent hypercalcaemia.

The OTSC®-clip in revisional endoscopy against weight gain after bariatric gastric bypass surgery.

The maintenance of the restrictive component of the Fobi pouch gastric bypass is essential for permanent weight control. Dilatation of the pouch-outlet and of the pouch itself is responsible for substantial weight gain by an increased volume per meal and binge-eating due to the rapid emptying. An endoscopic over-the-scope clip (OTSC®; Ovesco AG, Tübingen, Germany) was applied in 94 patients following gastric bypass and unintended weight gain by dilated gastro-jejunostomy to narrow the pouch-outlet. The OTSC®-clip application was safe and efficient to reduce the pouch-outlet in all cases. Best clinical results were obtained by narrowing the gastro-jejunostomy by placing two clips at opposite sites, hence reducing the outlet of more than 80%. Preferably, the clip approximated the whole thickness of the wall to avoid further dilatation of the anastomosis. Between surgery and OTSC®-clip application the mean BMI dropped from 45.8 (±3.6) to 32.8 (±1.9). At the first follow-up about 3 months (mean 118 days, ±46 days) after OTSC®-clip application the mean BMI was 29.7 (±1.8). At the second follow-up about 1 year (mean 352 days, ±66 days) after OTSC®-clip application the mean BMI was 27.4 (±3.8). The OTSC®-clip for revisional endoscopy after gastric bypass is reliable and effective in treating weight gain due to a dilated pouch-outlet with favorable short- and midterm results.

Evaluation of MR-angiography for pre-operative assessment of living kidney donors.

INTRODUCTION: Pre-operative magnetic resonance tomography (MR) and MR-angiography (MRA) have rendered favorable results for the assessment of renal anatomy preceding living-related kidney transplantation. However, limited value of MRA in the detection of accessory renal vasculature is reported. METHODS: We compared the results of pre-operative contrast-medium-enhanced MRA of the last 30 consecutively performed nephrectomies in living kidney donors with the intraoperative findings of vascular, parenchymal, and ureteral anatomy. RESULTS: Pre-operative MRA diagnosed a solitary renal artery in 24 cases (80%) and a normal venous, ureteral and parenchymal anatomy in all cases. Intraoperatively, the surgeon confirmed the normal pre-operative MRA findings of ureter and parenchyma. Yet, in 6 out of 30 patients (20%) vascular architecture differed from the pre-operative imaging: four of them, who had a radiologically regular anatomy, were found to have accessory vessels upon surgical preparation. In the fifth patient, MRA revealed an accessory lower polar artery, which was confirmed during surgery. An undiagnosed third arterial vessel, located behind the renal vein, led to an aortic bleeding. In the sixth case, the adrenal gland artery was misinterpreted as an accessory superior polar artery of the kidney in MRA. Additionally, a radiologically undetected inferior polar artery was dissected during nephrectomy and led to partial hypoperfusion of the graft. Subsequent retrospective reevaluation of the MRA by experienced radiologists was unable to identify the intraoperative anatomical discrepancies. Hence, sensitivity of MRA was 60% (6 out of 10 cases) for accessory renal vessel detection and 80% (24 out of 30 cases) for overall sensitivity in determining renal vessel number. DISCUSSION: MRA is a reliable method for the non-invasive investigation of living kidney donors and provides valuable information required by the surgeon. But, as the technique misses small diameter vessels, it cannot be recommended as sole diagnostic tool in unclear cases.

Vascular occlusion by ruptured balloon after percutaneous transluminal angioplasty.

PURPOSE: To report a rare case of chronic vascular occlusion by an undetected ruptured balloon fragment following percutaneous transluminal angioplasty. CASE REPORT: A 79-year-old man suffered from calf claudication 1 year after angioplasty for a short stenosis in the superficial femoral artery. During the femoropopliteal bypass operation, a ruptured angioplasty balloon was retrieved. CONCLUSIONS: Endovascular treatment of arterial lesions always requires thorough pre and postinterventional check of the applied instrumentation. A damaged catheter must initiate an immediate search for lost intravascular objects.