Abstracts

elevated view from the Storz camera has eliminated the need for laparoscopic vision.A wide variety of surgical interventions, including dissection, ligation, and retrievalhave been demonstrated. The control interface, coupled with stiffness in the system,provides for a stable operating platform. Further improvements are necessary intargeting, tissue manipulation, and system robustness. Conclusions: The Hydraprovides the foundation for development of a new generation of minimally-invasivesurgical instrumentation. Its straightforward design, complemented by NOTESToolbox 1.0, is amenable to application in a range of approaches.

S1399

Overclips As the Best-Performing Second Generation Flexible

Endoscopic NOTES�-Closure Technique in a Multioperator Two-

Phase Porcine StudyManuel Perez-Miranda, Ferran Gonzalez-Huix, Marisa Goyeneche,Carlos Dolz, Diego Juzgado, Pedro Gonzalez, Jorge C. Espinos,Francisco Igea, Enrique Vazquez-Sequeiros, Paul YeatonIntroduction: Safe closure can be accomplished by adapting laparoscopic devices toshort-route access NOTES. Reliable, simple and reproducible Flexible EndoscopicClosure Techniques (FECTs) are needed for transgastric NOTES. Whereas 1stgeneration FECTs fall short, 2nd generation FECTs have shown promise and arereadily available. Aim: To identify the best performing of four second generationFECTs, qualified by a) performability with available devices through a flexibleendoscope; b) feasibility and potential already shown; and c) lack of prior formalcomparative evaluations. Methods: Two-phase study. Phase I: 14 endoscopistswithout prior NOTES training closed NOTES access perforations (needle-knife &15-mm-balloon dilation) on a total of 52 pig stomachs/colons (half each). Organsfrom 100 kg animals isolated and frozen within 2 weeks were mounted onplatforms. All 14 operators carried out one closure each using T-Anchors (Cook),Clips (Boston Scientific) on Endoloops (Olympus), and Overclips (OTSC, circularclips mounted rubber-band-like on a cap at the endoscope tip, from Ovesco). 10carried out Submucosal Endoscopy with Mucosal Flap (SEMF) closures, created bysaline injection in the submucosa, needle-knife entry, and balloon dissection.Standard (Overclips & SEMF) or double channel (T-Anchors & ClipsþEndoloops)gastroscopes were used. Air leak testing was performed and data collected for eachclosure: a) success rate (1st & 2nd attempt); b) procedural time (min); c) leakpressure (mm Hg); and d) blinded complexity assessment by each operator ona 1-3 scale. Comparisons were made using univariate analysis, Scheffe test, and Chisquared where appropriate, in order to identify the best performing FECT. 10additional closures with the best ex-vivo performing FECT were carried out acutelyin Phase II on the stomachs and colons of 5 Large White pigs of 20 kg. After autopsy,leak testing was performed, and both leak pressure and complexity score werecompared with Student’s test to those in Phase I. Results: Overclips were identifiedin Phase I as the best performing FECT (Table). In Phase II, they reached a higherleak pressure 79.5 � 10.4 mm Hg (pZ0.06) with a no different complexity score.CONSLUSIONS: Overclips outperformed previously reported FECTs in 2-Phaseporcine ex-vivo and in-vivo closure study carried out by 14 novice operators.

COMPLEXITY

www.giejou

SUCCESSRATE(%)1st/2ndattempt

rnal.org

PROCEDURALTIME (min,X�SEM)

LEAKPRESSURE(mm Hg,X�SEM)

SCORE (easy-average-difficult)

T-Anchors

78 / 100 33.6 � 2.9 26.9 � 4.2 4-7-3 ClipsDLoop 93 / 100 21.0 � 1.4 13.5 � 2.0 3-4-7 Overclips 93 / 100 18.6 � 1.6 42.4 � 7.2 7-7-0 SEMF 50 / 50 59.8 � 8.3 19.5 � 7.2 1-0-9 p 0.032 0.00 0.02 0.001

S1400

A Randomized Study Comparing Hemostasis of Laparoscopic

Clips Delivered via Flexible Endoscopy Versus Conventional

Endoscopic Clips On Porcine Mesenteric VesselsPer-Ola Park, Richard I. Rothstein, Melina C. Vassiliou, David Stefanchik,Omar J. Vakharia, Kurt R. Bally, Paul SwainBackground: Clips designed for flexible endoscopic delivery are likely to be lesseffective for hemostasis on poorly supported vessels in the peritoneal cavitybecause they have a gap when closed and may not completely occlude a bleedingvessel. Laparoscopic clips with a spring-like closure design might be more effectiveon isolated and larger vessels, but have not until recently been deliverable viaflexible endoscopes. Methods: A new flexible clip applier (Flex Allport Clip Applier,Ethicon Endo-Surgery) (C1) which can pass through a 3.7 mm flexible endoscopechannel and delivers laparoscopic-type flat clips, was compared in a randomizedstudy with a conventional flexible endoscopic clip applier delivering clips of split

Vo

figure-of-eight type which open and then close as they are pulled into a metalcylinder (Olympus Long Clip HX-610-13S L) (C2). The vessels selected for thisrandomized acute study in two 30 kg pigs were the vessel bundles of the smallintestinal mesenteric arcade including one artery and two venae comitentes. Themesentery was incised on either side of the vessel bundle which was then randomlyallocated using a tossed coin to occlusion by C1 or C2 clips. Flexible appliers wereused to apply 2 clips of the same type to the vessel, which was then incised withscissors to assess efficacy of hemostasis (1Zno bleeding, 2Ztrivial oozing notrequiring intervention, 3Zsubstantial bleeding or spurting requiring immediateintervention). Results: 26 vessel bundles of 2mm were randomized to C1 clips(nZ13) and C2 clips (nZ13). A total of 26 C1 clips and 26 C2 clips were appliedprior to cutting the vessels. The total hemostasis score for C1 clips (17) wassignificantly (p!0.05) superior to the C2 clip (32). Only 1/13 C2 clips gave a perfecthemostasis score compared with 11/13 C1 clips (p!0.05). C1 vessels that did notreceive a perfect score were found to be compressed too far into the back of theclip. Substantial bleeding was seen after C1 clipping in 0/13 vs 9/13 in C2 clipping(p!0.05). Because of the jaw gap, the C2 clips could be moved along the vesselwhile the C1 clip could not. In separate experiments, both clip types were able toocclude larger vessels than those being tested, provided sufficient surroundingtissue was included in the jaws to fill the gap. Conclusions: These results confirmthat conventional flexible endoscopic clips are ineffective in stopping bleeding fromsevered, isolated, vessels of 2 mm unless there is sufficient extra tissue to fill thegap. A new flexible delivery system that delivered laparoscopic clips which flattenthe vessel was significantly more effective in this porcine hemostasis model.

S1401

Endoscopic Submucosal Dissection of Gastric Lesions Using

a Through-the-Scope Intuitively Controlled Robotics-Enhanced

Manipulator SystemLouis S. Phee, Khek Yu Ho, Asim Shabbir, Soon Chiang Low, VanAn Huynh, Andy P. Kencana, Kai Yang, Davide Lomanto, Jimmy B. So,Sheung Chee Sydney ChungBackground and Aims: Performing endoscopic submucosal dissection (ESD) withstandard endoscopic equipments is technically challenging due to limited degrees offreedom for maneuvering the tools. We developed a dexterous robotics-enhancedendosurgical system that could potentially overcome the technical hurdles. Thisstudy explores the feasibility of using the system in ESD and evaluated its performancevis-a-vis that of conventional endoscopy. Methods: The system comprises a mastercontroller, a telesurgical workstation, and a slave robotic manipulator. The master isattached to the wrists and fingers of the operator through an array of sensors andjoints. The slave comprises 2 manipulators - a grasper and a mono-polar diathermyhook which are separately inserted through the operating channels (2.8 mm, 3.7 mmdiameters) of the gastroscope. Movements of the operator are detected by sensorsand actuated into force signals driving the manipulators. The experiments were firstconducted on 5 Erlangen porcine stomachs before evaluation of the system’sperformance in 2 live pigs. For comparison, ESD was also performed usingconventional endoscopy. Gastric lesions measuring 20 mm were marked with needleknife before submucosal injection of 40 ml normal saline and 2 ml 0.04% indigocarmine solution. Dissection was carried out either using the robotics-controlledgrasper and hook or the IT knife. Outcome measures were lesion resection time,grasper and hook efficacy, completeness of resection, and presence of procedure-related perforation. Results: In study on Erlangen stomachs, 15 lesions located at thecardia, antrum, or body of stomach were successfully resected by the robotics system.All lesions were resected in a single piece under good grasping and retraction tension.Mean dimension of the resected specimens was 37.4� 26.5 mm. Mean resection timewas 23.9 min (8-48 min). There was no difference between resection times of lesionsat different locations. In live pigs, the robotics system took an average 23.5 min (18-29min) to complete the ESD. This compares with a mean dissection time of 16 min (9-23min) taken by the conventional system using IT knife. All lesions were resectedenbloc. Mean dimension of the specimens resected by the robotics system was 35.8�27.6 mm; that dissected by the IT knife averaged 39.5� 27.5 mm. There was no case ofperforation. Conclusion: ESD is feasible and safe using the robotics-enhancedendosurgical system. Although at this stage, no advantage over the conventionalmethod is obvious in ESD, we believe the system would perform better onceendoscopists become more accustomed to its usability and functionalities.

S1402

Endoscopic Pancreatic Necrosectomy in 28 Patients By EUS-

Guided NOTES�: Improved Method with Reduced Number of

Procedures and Low Complication RatesChristian Juergensen, Frank Neser, Joachim Boese-Landgraf,Detlef Schuppan, Stoelzel UlrichBackground: Surgery of infected pancreatic necrosis is associated with considerablehigh mortality. It remained to be shown if endoscopic necrosectomy via thestomach or duodenum using EUS-guided NOTES (Natural Orifice TransluminalEndoscopic Surgery) is feasible and can reduce complications and mortality.Methods: Endoscopic necrosectomy was performed in 28 patients between 2002

lume 69, No. 5 : 2009 GASTROINTESTINAL ENDOSCOPY AB163

Abstracts

and 2008 (median age 58y [21-83y], 23 male, 5 female). Indications for treatmentwere uncontrolled infection, sustained pain or symptomatic gastroduodenalcompression. Our procedure included three major steps. Step I: EUS-guided accessto the necrotic cavity and access enlargement. Step II: endoscopic necrosectomy incombination with interval stenting. Step III: readmission and stent change untilcomplete collapse of the cavity was achieved. Results: A median of 6 [1-16] sessionswere needed for access, necrosectomy and removal/exchange of stents. Hospitaldischarge of patients was considered once complete removal of the necroticmaterial was achieved. Median follow up was 20 months. In-patient mortality was4% (1/28) and related to aspiration of cyst-derived fluid two hours after drainage.Clinical and morphological remission was obtained in the remaining patients (96%).Nasocystic and transabdominal irrigation or extra endoscopic sessions for pureflushing could be avoided in all patients. Severe immediate complications wereencountered in 2 cases (one arterial and one variceal bleeding). During follow upadditional surgery was necessary in seven patients (cholecystectomy due to acutecholecystitis (nZ2), elective cholecystectomy (nZ3), symptomatic duodenalstenosis (nZ1), ileus due to intestinal adhesions (nZ1)). Surgery was neitherrelated to pancreatic necrosis nor to endoscopic treatment. Five deaths occuredduring follow-up which were unrelated to endoscopy or pancreatic necrosis.Overall, the number of complications related to pancreatic necrosis was far belowthat of conventional necrosectomy in historical series. Conclusion: The number ofpatients undergoing endoscopic necrosectomy is the largest cohort reported so far.The number of endoscopic interventions and the procedure related morbidity andmortality in our cohort is low as compared to historical data. In the light of thesuperior outcome of patients undergoing endoscopic necrosectomy, the role ofconventional surgery of infected necrosis has to be redefined.

S1403

Quality of Life After Appendectomy: A Prospective Pilot Study

Comparing Outcome After Flexible NOTES� Appendectomy in

Hybrid Technique and Laparoscopic AppendectomyJoern Bernhardt, Sylke Schneider-Koriath, Holger Steffen, Kaja LudwigIntroduction: Natural orifice transluminal endoscopic surgery (NOTES) is anemerging technique. The proposed advantages should be established by itscomparison with standard procedures. Peri- and postoperative complications area major focus of its evaluation. Material and Methods: Having performed our firsttransvaginal flexible appendectomy using a true NOTES technique in 2007, weinitiated the prospective comparison between transvaginal appendectomy in hybridtechnique versus standard laparoscopic appendectomy. Questionaire-basedevaluation included issues related to quality of life in addition to objective clinicalfindings. From 10/2007 to 11/2008, appendectomy was performed in 76 women ofwhom forty agreed to participate in the study with follow-up documentation for 35days. In three patients (mean age 29 ys), transvaginal appendectomy was performedemploying a two-channel gastroscope (Storz, Germany) with the use of a 5 mmtrocare at the umbilicus. Transvaginal appendectomy was considered a non-standardmedical procedure and required individual patient’s consent. Pre- and postoperativegynecological examinations were performed. Laparoscopic appendectomy was usedin 37 women (mean age 38 ys) using three trocars. The study was submitted to theethics committee of the University of Rostock. Results: All three women of the NOTESgroup and 16 of 37 women of the laparoscopy group returned questionnaires forevaluation. All removed appendices demonstrated typical inflammation. The onlypostoperative complication consisted of an intra-abdominal abscess afterlaparoscopic appendectomy. Major results of the questionnaire-based comparisonare summarized in the table. DiscussionBase on our initial experience, transvaginalflexible appendectomy appears to be a safe procedure performed in hybridtechnique. Preliminary data of the study point to shortened recovery intervals andimproved quality of life after the procedure. Further examination with additionalNOTES procedures is necessary to allow for meaningful statistical evaluation, and tofully explore the advantages of NOTES appendectomy.

Laparoscopic

Questionaire issue

AB164 GASTROINTESTINA

NOTESappendectomy

L ENDOSCOPY Volu

appendectomy

Food intake

Day of operation Day 1 Desire to discharge Day 1.3 Day 4.1 Return of gut functions Day 1 Day 2 Pain score (level 1-10) day 1 3 5.4 Pain score, day 3 2 3.1 Pain score, day 7 1 1.7 Overall condition scoredays 1/3, (1-7 Z well-bad)

1.7/1.0

4.2/2.6

Health fully restored

Day 7 Day 26 Fit for work/business Day 9 Day 23 Sexual activity Day 16 Day 20.5

me 69, No. 5 : 2009

S1404

Systematic Evaluation of the Over-the-Scope-Clip (OTSC) for

NOTES� Gastric ClosureRogier P. Voermans, Mark I. Van Berge Henegouwen, Willem Bemelman,Paul FockensBackground: Secure transluminal closure remains a fundamental barrier to the safetranslation of Natural Orifice Transluminal Endoscopic Surgery (NOTES) intohumans. Aims: 1) To compare acute ex vivo strength of Over-The-Scope-Clip (OTSC;Ovesco) gastrotomy closure to surgical suture. 2) To evaluate feasibility, safety andreliability of gastrotomy closure using OTSC in acute and survival porcineexperiments. Methods: The gastric opening was created by needle knife puncturefollowed by dilatation with 18 mm balloon. The closure procedure consisted of 3steps: 1. Approximation of muscular layers using a flexible twin grasper; 2. Pulling thetissue into the OTSC cap fitted at the tip of the scope; 3. Releasing the clip. 1) Ex vivocomparison study was conducted in an ex vivo porcine stomach model as a previouslydescribed by our group. Fifteen control gastrotomies, closed using surgical suture,resulted in a mean leak pressure of 206 mmHg (SD 59). Using a non-inferiority designa sample size of 11 specimens needed to be included in the OTSC group. 2) In vivoexperiments were planned first in 3 acute and later in 16 survival pigs. Sample size forsurvivals was based on the fact that the lower end of the 95% confidence interval (CI)of successful closure must be at least above the 80% and a success rate of 100%. In allpigs a standardized hybrid cholecystectomy was performed and gastrotomies wereclosed using the OTSC as described above. In the survivals necropsy was performedafter 10 days with inspection of peritoneal cavity and the gastrotomy site, which wasexcised and sent for histology. Results: 1) Ex vivo: Closure was successful in all 11specimens. Mean leak pressures was 224 mmHg (SD 61), which was non-inferior tothe gold standard (pZ0.003). 2) In vivo: Closure was endoscopically successful in allacute experiments and the 6 survival experiments performed until 11/08. Medianclosure time was 7 minutes. All survival animals thrived during 10 days follow up. Atnecropsy there were no signs of infection or other complications and only 3 adhesionsfrom the gastrotomy to the omentum. The gastrotomy was macroscopically full-thickness closed in all cases. In 2/6 the clip was still present at the closure site.Histology confirmed full-thickness healing with 100% success (95% CI: 61-100%).Conclusions: Use of OTSC for gastrotomy closure is feasible, easy to apply and resultsin histological proven full-thickness closure. It provides ex vivo burst pressurescomparable with surgical closure and appears to be safe and reliable in survivalexperiments with 6 out of 16 experiments completed.

S1405

NOTES� in Minimally Invasive Surgical Esophagectomy:

Technique of Endoscopic Transesophageal Mobilization of the

Esophagus in An Animal Model, a Preliminary StudyTimothy A. Woodward, Steven P. Bowers, Horacio J. Asbun, MichaelB. Wallace, Massimo Raimondo, Laith H. JamilBackground: The next generation of NOTES therapeutics has emphasized morepragmatic utilization of endoscopy as an adjunct to thoracoscopic or laparoscopicprocedures. Evolving from our mediastinal studies are methods in whichtransesophageal dissection of the esophagus may facilitate minimally-invasiveesophagectomy. Methods: Studies were approved by the Animal InstitutionalReview Board. Five fifty-pound pigs were intubated and underwent generalanesthesia. A standard endoscope was used to intubate the esophagus. A site waschosen on the right-lateral wall of the esophagus as a transesophageal entry siteinto the mediastinum (first determined by EUS; later by transillumination); a tenmillimeter superior mediastinal access site with mucosal flap in the region of thethoracic inlet/aortic arch was created with a needle knife following the injection ofGonak solution to facilitate tunneling. An Olympus dissecting cap and tenmillimeter biliary balloon allowed for entrance into the mediastinum. From thisvantage point, we were able to visualize the trachea; anterior indentation of thethoracic spine; posterior aorta; both branches of the vagus. Repeated insufflation ofthe biliary balloon allowed for bloodless dissection of surrounding structures alongwith the needle knife. Attempts were made to mobilize the esophagus in a 360-degree fashion from the entrance point down to the diaphragmatic hiatus. Similarattempts at access and mobilization were undertaken from the mid-esophagus/subcarina following EUS guidance in the first two porcine models. The pigs wereeuthanized immediately after dissection for necropsy. Results: Visualization of themediastinum and circumferential mobilization of the esophagus was obtainable viaa superior mediastinal approach. Structures and vessels were easily identified anddissection in the antegrade manner was undertaken without trauma to tissue withinthe dissection plane. Subcarinal access was encumbered by the difficulty ofretroflex dissection. Conclusion: To our knowledge, this is the first study to definethe technical challenges and feasibility of transesophageal endoscopic assistance tominimally invasive surgical esophagectomy. This study demonstrates thattransesophageal access to the mediastinum is possible, and can potentiallyaccomplish good exposure for mediastinal dissection of the esophagus, particularlygiven that the endoluminal access site would be removed with the specimen.

www.giejournal.org