Kai Matthes

EUS-guided photodynamic therapy with verteporfin for ablation of normal pancreatic tissue: a pilot study in a porcine model (with video)

BACKGROUND EUS-guided photodynamic therapy (PDT) with the photosensitizing agent porfimer sodium has been shown to be effective in ablation of pancreatic tissue. OBJECTIVE The objective of this study was to determine the effectiveness and safety of EUS PDT with verteporfin, a photosensitizer associated with less photosensitivity. DESIGN Prospective investigation of 6 swine that received an IV injection of 6 mg/m2 of verteporfin before EUS. SETTING Hospital animal laboratory. INTERVENTIONS The tail of the pancreas was located with EUS and was used to guide the placement of a light catheter. The pancreatic tail was exposed to 10, 15, or 20 minutes of laser light (689 nm). MAIN OUTCOME MEASUREMENTS Follow-up abdominal CT, liver and renal function tests, and serum pancreatic enzymes levels were performed. Histology of the pancreas was obtained 7 days after the procedure on necropsy. RESULTS Localized tissue necrosis within the pancreatic tail (range 6.6-30.5 mm in diameter) was seen in all animals. The diameter of the necrotic tissue was directly related to the dose of light. No post-procedural complications were observed. LIMITATIONS Normal animal model (lack of malignant tissue). CONCLUSIONS EUS-guided PDT of porcine pancreas with verteporfin achieved localized pancreatic tissue ablation in a dose-related fashion.

Efficacy of full-thickness GI perforation closure with a novel over-the-scope clip application device: an animal study

BACKGROUND A novel, over-the-scope clip (OTSC) system may be suitable for closure of various GI perforations. The strength and maximum diameter of closure for a single OTSC, however, are unknown. OBJECTIVE To determine the maximum closure capacity (diameter) and pressure threshold for a single OTSC. DESIGN Prospective ex-vivo study. SETTING Academic medical center. METHOD Full-thickness, standardized defects of 5 mm, 10 mm, 15 mm, 20 mm, and 25 mm were created in porcine stomachs. Similarly, full-thickness defects of 10 mm, 20 mm, 25 mm, 30 mm, and 35 mm were created in porcine colons. A single OTSC was endoscopically deployed 5 times for each full-thickness defect size in an ex-vivo endoscopic simulator. MAIN OUTCOME MEASUREMENTS Each closure site was tested under water with compressed air for burst pressure. RESULTS We achieved successful closure in all stomach defects ranging from 5 to 20 mm by using 12-mm OTSCs with short teeth and colon defects ranging from 10 to 30 mm with 14-mm OTSCs with short teeth. Mean (± standard deviation [SD]) burst pressures for the gastric closure sites were 74.9 ± 17.5 mm Hg for 15-mm defects, 49.3 ± 21.6 mm Hg for 20-mm defects, and 15.2 ± 4.1 mm Hg for 25-mm defects. Mean (± SD) burst pressures for the colon closure sites were 117.9 ± 40.1 mm Hg for 20-mm defects, 57.4 ± 4.2 mm Hg for 30-mm defects, and 10.9 ± 7.6 mm Hg for 35-mm defects. LIMITATIONS Ex-vivo study, does not reflect difficult locations. CONCLUSION Full-thickness tissue defects ranging from 5 to 20 mm in the stomach and from 10 to 30 mm in the colon can be closed adequately with a single OTSC in an ex-vivo experimental setting. Tissue defects larger than 20 mm in the stomach and 30 mm in the colon may require more than one OTSC or supplemental endoclips to achieve adequate closure. Endoscopic inspection of the closure site does not assure adequate closure of larger perforations.

Strategies for training in diagnostic upper endoscopy: a prospective, randomized trial

BACKGROUND Training simulators have been used for decades with success; however, a standardized educational strategy for diagnostic EGD is still lacking. OBJECTIVE Development of a training strategy for diagnostic upper endoscopy. STUDY DESIGN Prospective, randomized trial. SETTINGS A total of 28 medical and surgical residents without endoscopic experience were enrolled. Basic skills evaluations were performed following a structured program involving theoretical lectures and a hands-on course in diagnostic EGD. Subsequently, stratified randomization to clinical plus simulator training (group 1, n = 10), clinical training only (group 2, n = 9), or simulator training only (group 3, n = 9) was performed. Ten sessions of simulator training were conducted for groups 1 and 3 during the 4-month program. Group 2 underwent standard training in endoscopy without supplemental simulator training. The final evaluation was performed on the simulator and by observation of 3 clinical cases. Skills and procedural times were recorded by blinded and unblinded evaluators. MAIN OUTCOME MEASUREMENTS Time to reach the duodenum, pylorus, or esophagus. RESULTS All trainees demonstrated a significant reduction in procedure time during a simple manual skills test (P < .05) and significantly better skills scores (P = .006, P = .042 and P = .017) in the simulator independent of the training strategy. Group 1 showed shorter times to intubate the esophagus (61 ± 26 seconds vs 85 ± 30 seconds and 95 ± 36 seconds) and the pylorus (183 ± 65 seconds vs 207 ± 61 seconds and 247 ± 66 seconds) during the clinical evaluation. Blinded assessment of EGD skills showed significantly better results for group 1 compared with group 3. Blinded and unblinded evaluations were not statistically different. LIMITATIONS Small sample size. CONCLUSIONS Structured simulator training supplementing clinical training in upper endoscopy appears to be superior to clinical training alone. Simulator training alone does not seem to be sufficient to improve endoscopic skills.

One hundred and one over-the-scope-clip applications for severe gastrointestinal bleeding, leaks and fistulas

AIM To investigate the efficacy and clinical outcome of patients treated with an over-the-scope-clip (OTSC) system for severe gastrointestinal hemorrhage, perforations and fistulas. METHODS From 02-2009 to 10-2012, 84 patients were treated with 101 OTSC clips. 41 patients (48.8%) presented with severe upper-gastrointestinal (GI) bleeding, 3 (3.6%) patients with lower-GI bleeding, 7 patients (8.3%) underwent perforation closure, 18 patients (21.4%) had prevention of secondary perforation, 12 patients (14.3%) had control of secondary bleeding after endoscopic mucosal resection or endoscopic submucosal dissection (ESD) and 3 patients (3.6%) had an intervention on a chronic fistula. RESULTS In 78/84 patients (92.8%), primary treatment with the OTSC was technically successful. Clinical primary success was achieved in 75/84 patients (89.28%). The overall mortality in the study patients was 11/84 (13.1%) and was seen in patients with life-threatening upper GI hemorrhage. There was no mortality in any other treatment group. In detail OTSC application lead to a clinical success in 35/41 (85.36%) patients with upper GI bleeding and in 3/3 patients with lower GI bleeding. Technical success of perforation closure was 100% while clinical success was seen in 4/7 cases (57.14%) due to attendant circumstances unrelated to the OTSC. Technical and clinic success was achieved in 18/18 (100%) patients for the prevention of bleeding or perforation after endoscopic mucosal resection and ESD and in 3/3 cases of fistula closure. Two application-related complications were seen (2%). CONCLUSION This largest single center experience published so far confirms the value of the OTSC for GI emergencies and complications. Further clinical experience will help to identify optimal indications for its targeted and prophylactic use.

Hemodynamic efficacy of the over-the-scope clip in an established porcine cadaveric model for spurting bleeding.

BACKGROUND Clip application has been proven to be effective for endoscopic hemostasis. There are limited bench data on the efficacy of the over-the-scope clip (OTSC) for the treatment of spurting GI hemorrhage. We evaluated the hemodynamic efficacy of the OTSC in an established bleeding model. OBJECTIVE To evaluate the hemodynamic efficacy of the OTSC in an established bleeding model. DESIGN Prospective experimental trial with historical comparison. SETTING We tested the OTSC prospectively in a validated bleeding model by using the compact Erlangen Active Simulator for Interventional Endoscopy equipped with an upper GI organ package. The artificial blood circulation system of the simulator was connected to an arterial pressure transducer. Two investigators with different endoscopic experience (4000 and 10,000 endoscopies performed) participated. Each investigator treated 16 bleeding sites in the simulator with the OTSC by using only suction (n = 8) and a novel retraction device to grasp tissue (n = 8). Systemic pressures were recorded 1 minute before, during, and 1 minute after clip application to objectify the effects of clipping on the vessel diameter. MAIN OUTCOME MEASUREMENTS Mean and maximum reduction in vessel diameter. RESULTS The application of the OTSC on the bleeding vessel led to a significant increase in systemic pressure (P < .001) and decreased vessel diameter (P < .001) independent of the endoscopic experience of the investigator. There was no difference in the decrease in vessel diameter based on the application technique (suction vs suction plus grasping). A historical comparison with our former trials demonstrated that the OTSC decreased the vessel diameter significantly more than other traditional endoclips. LIMITATIONS Small sample size. CONCLUSIONS We could demonstrate the efficacy of the OTSC with increased hemodynamic efficiency compared with other endoscopic clip devices tested previously.

Prospective, randomized comparison of 3 different hemoclips for the treatment of acute upper GI hemorrhage in an established experimental setting

BACKGROUND Recently, endoscopic clip application devices have undergone redesign and improvements to optimize their clinical use and effectiveness. Initially designed for the treatment of bleeding nonvariceal lesions, these devices are also increasingly used for the closure of perforations, fistulas, and anastomotic leaks. Several clinical studies, both randomized and nonrandomized, have used endoscopic hemoclips for hemostasis. However, no comparative studies have yet been reported in the literature comparing the latest endoscopic clip devices for usability and effectiveness for hemostasis of acute upper GI hemorrhage. OBJECTIVE We aimed to compare the usability and efficacy of 3 different types of endoscopic clip application devices in an established experimental setting by using a porcine ex-vivo simulator of upper GI hemorrhage. DESIGN Randomized, controlled, ex-vivo study. SETTING Academic medical center. METHODS Spurting vessels were created within ex-vivo porcine stomachs as published in prior studies. The vessels were attached to a pressure transducer to record the pressure of the circulating blood replacement. Before the initiation of bleeding, each vessel was randomized to 1 of 3 endoscopic clipping devices: 2 different commonly used hemoclips deployed through the working channel and 1 novel clip deployed via an over-the-scope applications device. Two investigators treated 45 bleeding sites (15 bleeding sites for each device at various randomized locations in the stomach: fundus, body, and antrum). MAIN OUTCOME MEASUREMENTS Usability was measured via the endpoints of procedure time and quantity of clips required to achieve hemostasis. Efficacy was measured via the endpoint of pressure increase (Δp) from baseline to after treatment. RESULTS All of the 45 hemostasis treatments were carried out successfully. The mean procedure times were significantly different among the hemoclips, with the clip deployed in an over-the-scope fashion requiring significantly less time to attain hemostasis compared with the other 2 clips. For number of clips needed to attain hemostasis, the clip deployed in an over-the-scope fashion was significantly superior to the others. There were also significant differences among the changes in pressure (Δp ± SD) among the different hemoclips tested. LIMITATIONS Ex-vivo study. CONCLUSIONS In this prospective, randomized ex-vivo study, we observed significant differences in the usability (time to achieve hemostasis and number of clips required) and the efficacy (change in pressure achieved by the hemoclips) among the 3 clips. The clip applied in the over-the-scope fashion was superior to the other 2 tested clips with regard to time to achieve hemostasis and number of clips required.

Triluminal Hybrid NOS as a Novel Approach for Colonic Resection With Colorectal Anastomosis

Background: Minimal invasive surgery has led to a significant decrease in surgical trauma, pain, recovery time and improved cosmesis compared with open surgery. However, scar development and the risk of hot spots for infections and hernias are still present. Natural orifice surgery (NOS) promises to offer even further reduction in invasiveness and thus may lead to even faster recovery. The goal of this study was to establish a NOS colonic resection by using commercially available standard surgical instruments avoiding major abdominal incisions. Methods and Results: This article reports a new triluminal hybrid NOS approach for sigmoid and colonic resection (Tri-Port-NOS-SIG), established using rigid laparoscopic instruments through the umbilicus, the vagina, and the rectum, without any major abdominal incision. The specimen was retrieved through the anus avoiding dilatation of the vagina. In an early series of 5 patients the first patient was a 37-year-old woman with a 10-year history of recurrent diverticulitis. She recovered quickly and was discharged on postoperative day 2. She returned to sports activity on day 12 postoperatively and to her heavy-duty job on day 16. The following 4 patients also recovered well and were discharged on postoperative days 7 (2 patients), 8, and 11, respectively. One patient experienced a temporary, mild paresthesia of the left lower dorsal leg, most likely because of intraoperative positioning. No major complications occurred. Conclusion: Tri-Port-NOS-SIG offers a feasible scarless approach for abdominal resections using commercially available surgical instruments in experienced hands.

Efficacy of a prototype endoscope with two deflecting working channels for endoscopic submucosal dissection: a prospective, comparative, ex vivo study

BACKGROUND Optimizing the visualization of the cutting line of the submucosal layer is essential to performing an effective and safe endoscopic submucosal dissection (ESD). OBJECTIVE To evaluate the prototype R-scope compared with a conventional, double-channel endoscope in time required for ESD of mucosal lesions in distinct anatomical locations of the stomach. DESIGN A prospective, comparative, ex vivo study. INTERVENTION ESD. MAIN OUTCOME MEASUREMENTS Procedure time (primary end point measure), specimen size, submucosal injection frequency, en bloc resection rate, and perforation rate (secondary end point measures). RESULTS In the subgroup of resections in the greater and lesser curvature, the mean (+/- SD) procedure time was significantly less in the R-scope group compared with the conventional endoscope group (8.4 +/- 2.1 minutes vs 11.3 +/- 2.1 minutes, respectively; P = .006), and the mean (+/- SD) submucosal injection frequency was significantly less in the R-scope group compared with the conventional endoscope group (1.9 +/- 0.6 vs 2.5 +/- 0.5, respectively; P = .025). There were no significant differences in procedure time, specimen size, submucosal injection requirements, en bloc resection rate, and perforation rate between the two endoscopic groups of all combined anatomic lesions. LIMITATIONS Small, ex vivo study. CONCLUSION ESD by using the R-scope may provide an improved platform for quicker ESD, especially in greater and lesser curvature anatomical lesions of the stomach.

64-Slice multidetector row CT angiography of the abdomen: comparison of low versus high concentration iodinated contrast media in a porcine model

OBJECTIVE In this study we aimed to assess the image quality and degree of vascular enhancement using low-concentration contrast media (LCCM) (300 mg I ml(-1)) and high-concentration contrast media (HCCM) (370 mg I ml(-1)) on 64-slice multidetector row CT (MDCT) abdominal CT angiography (CTA). In addition, we aimed to study the feasibility of using HCCM with a reduced total iodine dose. METHODS CTA of the abdomen on a 64-slice MDCT was performed on 15 anaesthetised pigs. Study pigs were divided into three groups of five each based on the iodine concentration and dose received: Group A (LCCM; 300 mg I ml(-1)), Group B (HCCM; 370 mg I ml(-1)) and Group C HCCM with 20% less iodine dose. The total iodine injected was kept constant (600 mg kg(-1)) in Groups A and B. Qualitative and quantitative analyses were performed to study and compare each group for image quality, visibility of the branch order of the superior mesenteric artery (SMA), artefacts, degree of enhancement in the aorta and main stem arteries and uniformity of enhancement in the aorta. Groups were compared using the analysis of variance test. RESULTS The image quality of 64-slice MDCT angiography was excellent with a mean score of 4.63 and confident visualisation of the third to fifth order branches of the SMA in all groups. Group B demonstrated superior vascular enhancement, as compared with Groups A and C (p≤0.05). Uniform aortic enhancement was achieved with the use of LCCM and HCCM with 20% less iodine dose. CONCLUSION 64-slice MDCT angiography of the abdomen was of excellent quality. HCCM improves contrast enhancement and overall CTA image quality and allows the iodine dose to be reduced.

Role of computed tomography perfusion in the evaluation of pancreatic necrosis and pancreatitis after endoscopic ultrasound-guided ablation of the pancreas in a porcine model.

Objectives: To evaluate the role of computed tomography (CT) perfusion in detection of pancreatic necrosis and pancreatitis after endoscopic ultrasound-guided ethanol ablation of porcine pancreas and to correlate the evaluation with histopathology. Methods: Under endoscopic ultrasound guidance, 0.9% saline (control) and ethanol at 60%, 80%, and 100% concentrations were injected into the pancreatic tails of 4 pigs. On day 4, dynamic perfusion CT of the pancreas was performed. Perfusion analysis and evaluation of enhancement characteristics were done and correlated with histopathology. Results: Ethanol injections at 80% and 100% concentrations resulted in focal necrosis surrounded by focal pancreatitis, whereas 60% ethanol injection caused severe focal pancreatitis with microscopic necrosis. The necrotic area revealed reduced blood flow, blood volume, permeability-surface area product, and increased mean transit time compared with pancreatitis and normal tissue (P ≤ 0.001). In the control pig, no pancreatitis or necrosis was observed on perfusion images and histopathology. Conclusions: Pancreatic necrosis and pancreatitis after ethanol injection reduced the tissue perfusion on CT in comparison to normal tissue, with the changes being more substantial in necrosis than pancreatitis. These findings have possible implications in the accurate detection of pancreatic necrosis in patients with severe pancreatitis.