In-Vivo Remote Manipulation of Modified Capsule Endoscopes Using An External Magnetic Field

Abstracts

accomplished through the working channel of a therapeutic gastroscope fitted with a banding cap that was positioned flush against the mucosa around the defect. Extragastric air was continuously vacuumed at 8 mm Hg through an exit port and into a portable infrared spectrometer. SF6 concentrations were recorded every 2 s and plotted. Data was analyzed for time to positive (TTP) readings and slope (m) of SF6 concentrations (determined by best-fit lines). A leak was defined as a rise in SF6 concentration O 0.05 ppm. The stomachs were then immersed in water and distended by endoscopic insufflation of room air. A leak was defined by the presence of bubbles. Results: Intact stomachs and 23 g needle stomachs (n Z 3) were both SF6 test negative and bubble test (BT) negative. The 21 g needle stomachs (n Z 3) were SF6 positive (mean TTP 85.3s, mZ0.0360 ppm/s) but BT negative. The 18 g needle stomachs (n Z 3) were both SF6 positive (mean TTP 69.3s, m Z 0.049 ppm/s) and BT positive. The difference between the 18 g and 21 g TTP and slopes were not statistically significant (p Z 0.4 and 0.6, respectively). Two sutured stomachs were tested. Both were SF6 positive but BT negative. One had sutures visible at the defect (TTP 43s, mean mZ0.029 ppm/s). The second did not (TTP 68s, mZ0.007 ppm/s). Conclusions: Extragastric SF6 is detectable and quantifiable in defects as small as a 21 g needle. The SF6 leak test appears more sensitive than the water immersion bubble test. Further investigation into establishing the quantitative criteria to distinguish the size of leaks and their relevant clinical outcomes in in vivo models are currently underway.

S1377 Transgastric Access to Peritoneal Cavity Using Novel One-Step Needle Sphincterotome Philip W. Chiu, James Y. Lau, Candice C. Lam, Johnson Yip, Joseph J. Sung, Enders K. Ng IntroductionAccess to peritoneum is the first challenge for Natural Orifice Transluminal Endoscopic Surgery (NOTES). Conventionally, transgastric access is achieved by puncturing the gastric wall with needle knife followed by balloon dilatation. This method carries risk of adjacent organ damage, and is prolonged by exchanging instruments. This study aimed to test the efficacy of a new prototype one-step device (Olympus Medical Systems Co., Japan) (Fig 1) for transgastric access to peritoneum. Method: Five 30kg pigs were randomly assigned to receive either needle knife followed by balloon dilatation (conventional group) or one step needle sphincterotome (one-step group) transgastric access under general anesthesia. Double channel endoscope was used. For one-step group, after initial gastric puncture, the needle was withdrawn and CO2 was insufflated through the channel into peritoneal cavity. A guidewire was passed and the gastrotomy was extended using sphincterotome part. The success of all procedures was defined as entrance into the peritoneal cavity. Results: 20 transgastric access procedures were performed in five pigs, 10 for each group. The average time of transgastric peritoneal access for the conventional group was 676.6 seconds, while that for the one-step group was 358.8 seconds (p Z 0.02y). The average number of clips required to close the gastrotomy was 2.8 in the conventional group and 3.5 in the one-step group (p Z 0.57). There was one injury to the anterior abdominal wall during the procedure of entrance in the conventional group. Uncontrolled hemorrhage was encountered in one of the procedures performed using the onestep needle sphincterotomy during the initial incision. Postmortem examination found that the incision lacerated the gastroepiploic artery. Conclusion: Transgastric access to peritoneum for performance of NOTES is hastened with a novel one-step needle sphincterotome. The gastrotomies produced by the one-step knife, however, required more clips to close.

an adequate gastrotomy closure site in a reproducible manner. Our aim was to access the efficacy of a prototype endoscopic gastrotomy closure device developed by the CookÒ Medical Company. Methods: Six domestic swine were utilized for this study, after obtaining animal research review board approval. A standard endoscopic gastrotomy was performed using a needle knife puncture of the anterior gastric wall, and dilation of the tract was executed using a controlled radial expansion (CRE) balloon. Gastric closure was performed using a prototype device developed by CookÒ Medical. The device consists of a T bar which is punctured through the gastric wall adjacent to the gastrotomy margin using an endoscopic ultrasound needle delivery system. The T bar is pre-attached to a string. After two T bars are deployed on either side of the gastrotomy margin, a separate anchoring system is then deployed over the respectively attached strings, theoretically securing the tissue approximation and creating a closure. Efficacy of closure was tested on necropsy by performing a betadyne solution leak test and mechanicovisual inspection of the site for defects. Results: A total of 20 prototype closure devices were utilized for a total of eight gastrotomies.Two pigs had 2 gastrotomies performed sequentially in the same endoscopic session, with each gastrotomy requiring two T bars. Two pigs had four T bars deployed for one gastrotomy closure each. T bars were deployed too far apart on one gastrotomy, resulting in inability to closely approximate gastric tissue for closure. Four of the gastrotomy closure procedures were complicated by entanglement of the T bar strings within the stomach, so we could not effectively deploy the necessary anchoring device. All 8 porcine gastrotomy closures failed betadyne gastric infusion leak testing on necropsy. Macroscopic defects were also found with mechanical probing of all closures using a hemostat on necropsy. Four T bars were deployed inadvertently into abdominal viscera (2 liver, 2 spleen) and one was deployed onto the anterior abdominal wall as determined on final necropsies. Conclusion: This prototype device does not allow for adequate endoscopic gastrotomy closure due to failure to achieve effective tissue approximation and inability to estimate the depth of transgastric deployment. Further development of this product is necessary before future clinical applications can be made.

S1379 New Method of Gastric Incision Closure in NOTES: Short Term Survival Study Emad Y. Rahmani, Lynetta Freeman, Stuart Sherman, Michael V. Chiorean, Don J. Selzer Background: Reliable closure of the gastric incision is one of the most important steps in NOTES procedures. Objectives: To evaluate the feasibility, efficacy and safety of a new prototype suturing device in a short term survival study in dogs after NOTES ovariectomy. Methods: Evaluation of gastric incision closure in nine dogs who underwent NOTES ovariectomy. Following trans-gastric ovariectomy, the gastric incision was closed using a prototype T-fastener device attached to a standard flexible endoscope. Four sutures were used per incision in 8 dogs (2 sutures in one dog). The animals were followed up clinically for ten days postoperatively and euthanized for post-mortem examination. The animals were closely monitored for any ‘‘leak’’ symptoms such as pain, tachycardia, hypertension, avoidance of food, or fever. Blood samples for surgical stress responses (IL-6, CRP), metabolic response parameters (cortisol, glucose and pre-albumin) were measured. Post-operative pain was evaluated by physiologic parameters and a standardized pain score (the Melbourne pain score). On day 10, the incisional healing as well as injury to surrounding organs were analyzed by an experienced pathologist during a necropsy examination. Setting: Academic Veterinary Hospital. Intervention: NOTES gastric incision closure using a prototype T-fastener/ endoscope attachment. Results: The mean time for the gastric closure was 38 minutes. Pain threshold measurements increased postoperatively before returning to baseline within 36 hours. All animals ate their first meal within 6 hours of the procedure. At necropsy, all sites were healing as expected. There was no significant damage to surrounding organs and no evidence of peritonitis. All cultures were negative for aerobic bacteria. Conclusion: The new gastric incision closure device described seems to be effective and safe. With further improvements to the prototype we expect to reduce the closure time to less than 15 minutes. Further long-term study in live animals using this device is underway. This study was conducted in compliance with, and under the oversight of the Purdue Animal Care and Use Committee, Purdue University, West Lafayette, IN. The study is supported by a grant from NOSCAR/ASGE. T-Fastener devices provided by Cook Endoscopy.

Fig 1.

S1378 Efficacy of Novel Endoscopic Gastrototomy Closure Device in Porcine Models Jennifer S. Chennat, Alberto Herreros De Tejada, Vihar C. Surti, Marek a. Niekrasz, Craig L. Wardrip, Irving Waxman Background: With the advent of Natural Orifice Translumenal Endoscopic Surgery (NOTES), transgastric approaches to the peritoneal cavity have become a regularly utilized portal. One of the main obstacles to this novel type of surgery is performing

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S1380 In-Vivo Remote Manipulation of Modified Capsule Endoscopes Using An External Magnetic Field Frank Volke, Jutta Keller, Andreas Schneider, Jeremy Gerber, Meike Reimann-Zawadzki, Elisha Rabinovitz, Charles a. Mosse, Paul Swain Background: Remote control of wireless capsule movement would enhance diagnostic accuracy and might allow targeted biopsy. The efficacy and safety of

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Abstracts

remote manipulation of modified capsule endoscopes using external magnetic fields were assessed in in-vivo survival studies in pigs as part of a European FP6 project called NEMO. Methods: Model and real wireless capsules (Colon & ESO, by Given Imaging Ltd) were modified to include magnetic material aligned to give different field patterns and strength when exposed to an external magnetic field. The magnetic reed switch in the capsule was inactivated to allow continuous real-time viewing. Capsules were placed in the esophagus and stomach of anesthetised pigs (n Z 8, 34-78 kg). An external magnet was used to manipulate the capsule with gastroscopic visualisation. Capsules were attached to a thread to allow withdrawal through the cardio-esophageal junction and to measure forces needed to overcome magnetic attraction and peristaltic forces. The ability of a magnetic field to prevent retropulsion of an electrostimulation capsule causing esophageal contraction was tested. Anterior, lateral and posterior external magnet positions and movements were studied with the animals on the back, left lateral and prone positions. Results: An external plate magnet was effective in holding the capsule in specific locations in the esophagus. Swivel motions were particularly effective using small rotations of the external handheld plate magnet allowing multiple axial panning circular views of the squamocolumnar junction to be obtained. Caudo-cranial axial magnet rotations caused capsules to somersault in the esophagus. Water lubrication enhanced esophageal capsule movement. In the stomach capsules could be manipulated at will throughout the stomach. It was possible but difficult to drive capsules through the cardio-esophageal junction and move capsules into the pylorus but not to release them in the duodenum by removing the magnetic field. Somersaulting and rapid exploration of the stomach was easy. The magnetic field prevented esophageal retropulsion of an electrostimulation capsule. All pigs were well, eating immediately after recovery - esophagus and stomach looked normal at follow up endoscopy. Left lateral position with a posterior hand held magnet was the best for most manipulations. Conclusions: Magnetic capsules could be swivelled, somersaulted, stopped and moved when constrained by an external magnetic field. Such movements were especially effective in enhancing visualization in the esophagus and stomach and were safe when the internal magnetic arrangement was matched to the external magnet and the size of the animal.

S1381 Mucosal EGG, Performed Endoscopically, Predicts Response to Temporary and Permanent GES in Gastroparetic Patients Narendra Siddaiah, John M. Runnels, Mark Runnels, Robert Schmieg, J.R. Salameh, William Johnson, Thomas L. Abell Introduction: Temporary Gastric Electrical Stimulation (tGES) alleviates the symptoms of gastroparesis (GP) and most patients who have tGES undergo permanent (pGES) device implantation. We previously reported on the use of tGES via PEG or endoscopy (GIE, 2005 61: 455-6) as well as endoscopic tGES in a large number of pts (GIE, 2006:63; 5, AB103.). We now report on the use of mucosal EGG as a predictor of response to temporary and permanent GES. Patients: Of 394 consecutive patients (74 m, 274 f, mean age 43 years) from our regional database, we examined 150 patients who underwent tGES followed by pGES, and who also had mucosal EGG performed at the time of tGES: with diagnosis: idiopathic (I, 88), diabetic (D, 40), post surgical (PS, 22). Methods: Temporary GES was performed as previously reported (above) and if successful, was followed by permanent GES. During follow-up (10 months to 5 ½ years), of patients responding to tGES, symptom outcome was correlated with pGES. Patients were assessed by symptom scores [nausea (N), vomiting (V), and total symptom (TSS)] and IDIOMS (a HRQOL measure) at baseline (b), after tGES (t) and at the latest (L) available follow-up. The ratio of frequency to amplitude ratio in tGES mucosal electrogastrograms (Rt) was assessed in all patients undergoing tGES. Using linear regression, with latest vomiting score as the dependent variable, we determined the independent variables that predicted this outcome. Results: In subset analysis by etiology, virtually all patients I (p ! 0.0001) DM (p % 0.0001), and PS (p % 0.001) had very good responses in all assessed scores and IDIOMS to both tGES and pGES. Among all categories of GP, linear regression analysis identified a low Rt derived by the use of mEGG as the single best predictor of response to tGES and pGES. Other predictors of improvement in vomiting score after pGES: patient age, [Age ALL: t (p) -2.49 (0.01); I: t (p)-1.86 (0.06); D: t (p) -1.2 (0.23); PS: t (p) 0.28 (0.78)] and baseline vomiting score [Vb ALL: t (p) 3.5 (! 0.001); I: t (p) 3.23 (0.001); D: t (p) 1.79 (0.08); PS: t (p) 1.04 (0.31)]. In subset analysis, the above predictors were most significant for ID. Conclusions: Endoscopic mucosal EGG derived Rt, may be predictive of response to GES, especially improvement in vomiting, for certain GP patients. The lack of significance in D and PS groups may be due to a smaller sample size. Further trials of this diagnostic test can refine its exact role in the selection of GP patients for stimulation therapies.

INDEPENDENT

ALL

IDIOPATHIC

DIABETIC

POST-SURGICAL

Rt

t-stat. (p)value 2.87 (! 0.005)

t- (p) 2.76 (0.007)

t- (p) -0.44 (0.66)

t- (p) 1.08 (0.3)

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S1382 Is Capsule Endoscopy Accurate Enough to Screen Cirrhotics for High Risk Varices & Other Lesions? A Blinded Comparison of EGD & PillCam ESO Dennis M. Jensen, Bhavneet Singh, Disaya Chavalitdhamrong, Thomas O. Kovacs, Martha Carrico, Steven-Huy B. Han, Francisco a. Durazo, Sammy Saab Endoscopic screening (EGD) of cirrhotic patients (pts) with no prior UGI hemorrhage (UGIH) is the best method to identify high risk varices & other UGI lesions (HRVL) requiring 1 prophylaxis or other treatments. Whether capsule endoscopy (PillCam ESO Capsule-Ethicon/ Given) is as convenient, reliable, or accurate as EGD for detection of HRVL is controversial. Methods: 53 cirrhotics without prior UGIH gave informed consent for same day screening for HRVL with PillCam ESO & EGD. Mean age was 52.4 yrs. & most pts had Hep C or alcoholic cirrhosis. Transplant hepatologists referred pts & later treated those with high risk esophageal (EV) or gastric varices (GV) with banding or b-blockers; severe portal hypertensive gastropathy (PHTG) with b-blockers; or ulcers, esophagitis, or gastroduodenal erosions (GDE) with PPI’s. 2 hemostasis MD’s did all EGD’s & completed study forms, with standard grading for EV, GV, & PHTG. Coded capsule tracings were read by 2 investigators, blinded to EGD findings, using standard grading. Discrepancies in capsule or EGD readings were reconciled by consensus of respective groups. Comparisons were made by a statistician of sensitivity, specificity, & accuracy for grading HRVL. Results: There were 3 capsule failures but none with EGD. Median time for EGD ( biopsy) was 4 mins (70% pts had no IV sedation) vs. 20 mins for capsule (N Z 50). There was 0 mins median recovery time with either. Esophagitis (4), ulcers (4), angiomas (3), GV’s (5), or GDE (15) were seen with EGD in 23 pts (46%) but only 5 pts with capsule. The capsule did not pass into or record in the stomach in 13 pts (26%). Complete examinations were performed in all EGD pts. By EGD (vs. capsule), grades of EV were none 12 (9), small 15 (12), medium 15 (21), large 8 (8). Of the 38 pts with EV’s, red markings were seen in 16 by EGD (5 by capsule); EV’s or red marks were not detected by capsule in 11 pts. Overall accuracy ( SE) of capsule (vs. EGD) for detecting EV’s was 61  7%; grading EV’s was 77%  6%; detecting EV red marks was 46%  7%; & grading PHTG was 32%  14%. Conclusions: Compared to EGD: 1. Overall accuracy of capsule for detecting & grading EV’s was modest, but for detecting EV red markings & grading PHTG was low. 2. Capsule took significantly longer to perform & interpret. 3. PillCam ESO was not accurate for detecting clinically significant focal GD lesions including GV, ulcers, angiomas, or erosions. 4. Most pts accepted EGD without IV sedation. This was effective & quick for screening & is highly recommended, pending capsule improvements. Grant support from Ethicon, Pentax, & NIH grants (K24-DK002650) & CURE Human Studies Core (P30-DK041301).

S1383 Can Magnification Narrow-Band Imaging (NBI) Colonoscopy Determine Invasion Depth of Early Colorectal Cancer? - A Prospective Study Masakatsu Fukuzawa, Satoru Taira, Yutaka Saito, Takahisa Matsuda, Hiroko Hara, Chizuko Manabe, Hiroyuki Tachibana, Fumihiko Yanagisawa, Masaya Nonaka, Yasutaka Hayama, Kenji Yagi, Toshihiro Oshima, Mari Ko, Mikinori Kataoka, Kohei Kawakami, Takao Itoi, Takashi Kawai, Yoshihiro Sakai, Fuminori Moriyasu Background: We previously conducted a colonoscopic study using a narrow-band imaging (NBI) system on 112 early colorectal cancer lesions that revealed two factors, vessel density (non-dense; p Z 0.007) and regularity (negative; p Z 0.04), as having significant correlations with submucosal (sm) deep invasive cancer (O 1000 mm) among vessel findings as observed by NBI magnification colonoscopy. (ASGE ’07). Aim: We prospectively examined the usefulness of magnification NBI for diagnosing invasion depth in early colorectal cancer. Subjects: We studied 65 colorectal tumors (61 patients) R10 mm observed by conventional and chromoendoscopy, magnification chromoendoscopy (pit pattern analysis) and magnification NBI that had undergone endoscopic or surgical treatment at Tokyo Medical University Hospital from June to November 2007. Methods: A single experienced endoscopist prospectively evaluated the presence or absence of nondense vessels and negative vessel regularity using magnification NBI (100x view) in comparison to representative photographs of model examples. When both findings (non-dense vessels and negative vessel regularity) together were considered as an indicator for sm deep invasion, sensitivity, specificity and diagnostic accuracy were compared with conventional, chromoendoscopic and magnification chromoendoscopic (pit pattern analysis) depth diagnosis. Results: The patient male/female ratio was 40/21 and the median age was 64.4  4.2 years. Histological diagnosis included adenoma, mucosal and sm-superficial (1000 mm R)/sm-deep (O 1000 mm): 56/9 (85%/15%); and macroscopic types Is,Isp/IIa,IIc/ LST-G/LST-NG: 33/21/7/4 (50%/32%/11%/7%). Magnification chromoendoscopy (pit pattern analysis) and magnification NBI both were better in terms of sensitivity, specificity and accuracy compared to conventional and chromoendoscopic depth diagnosis while magnification NBI diagnostic accuracy was equivalent in comparison to magnification chromoendoscopy (pit pattern analysis). Sensitivity/specificity/ accuracy results were 80.8%/96.4%/93.8% for conventional and chromoendoscopy,

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