Paul Swain

A through-the-scope device for suturing and tissue approximation under EUS control.

BACKGROUNDnThe ability to place sutures under EUS control might allow development of a new type of transluminal endosurgery. The aim of this study was to develop endoscopic methods for suturing to variable predetermined depths in the wall of the GI tract and to allow fixation of adjacent hollow organs under EUS control.nnnMETHODSnA suturing device was constructed for suturing under EUS control to any desired depth. Sutures can also be placed into hollow or solid organs within 5 cm of the endoscope tip. The device allows multiple sutures to be placed without withdrawing the endoscope. Stitching, knot-tying, and thread-cutting are achieved through a 2.8-mm accessory channel.nnnRESULTSnMultiple (>100) sutures were placed in predetermined gut wall layers in pigs. Sutures were placed in the gallbladder (n = 7) and small intestine (n = 8) to fix the gallbladder/small intestine to the stomach and allow traction for the insertion of stents and other devices through the 2 lumens.nnnCONCLUSIONnA new method for stitching under flexible EUS control is described. This technology was used to place sutures at precise depths in the GI tract. It allowed fixation of other organs to the accessible GI tract for various purposes including delivery of stents and devices for creating anastomoses.

⁎⁎⁎4470 Endoscopic gastroplasty for gastro-esophageal reflux disease.

Aim : The aim of this study was review the results of endoscopic gastroplasty in a series of patients. Methods : Endoscopic Gastroplasty was performed at flexible endoscopy in 102 patients with Gastroesophageal Reflux Disease uncontrolled by long-term medical therapy and who were offered and declined anti-reflux surgery (open or laparoscopic) or were deemed unfit for general anesthesia due to concurrent illness. GERD was confirmed by preoperative manometry and 24 hour ambulatory pH studies. Using a 9mm diameter endoscopic sewing machine a neo-esophagus of 1-2 cm was created below the cardio-esophageal junction by placing sutures and securing the tissue with 4 half-hitches tied extracorporeally. Results : The operation was performed as a day-case procedure under sedation and the median duration of the procedure was 35 minutes. Post-operative assessment was made at a median of 12 weeks (8-52) with respect to symptoms, manometry and 24 hour ambulatory pH studies. Symptoms assessed by DeMeester symptom score improved from a median of 5 to 1 [p

7071 Endoscopy without air insufflation.

Background: Most gastrointestinal endoscopy is performed with inflation with air to distend the viscus. For some applications and the development of new endoscopic methods airless endoscopy is likely to become important. Little is known about the efficacy and limitations of airless gastrointestinal endoscopy. Methods: A variety of experimental airless endoscopes were constructed. These included: 1. short focal length lens of a) curved shape, b) conical shape were mounted on the tip. 2.Wire cage fronted endoscope. 3. Transparent balloon fronted airless endoscope: balloon filled with a) clear gas, b) clear water. 4.Water immersed endoscope. Lighting was transmitted either through the lens, cage, balloon, water or by mounting the light source coaxially adjacent to the lens or optics. These experimental endoscopies were tested in post mortem and live oesophagus, stomach, small bowel and colon. Results: Reasonably good quality video images were obtained using all these experimental endoscopes in airless endoscopy of the GI tract. Short focal length lenses required careful focussing to optimise image quality. Reflections from the cage were diminished by using a non-reflecting paint. Mucus adherence was occasionally a problem but mucus was often wiped off as the endoscope moved. Movement of the endoscope allowed assessment of whether the mucus was adherent to the lens or tissue. Gas and water filled transparent balloons gave moderately good views but were unreliable and not robust. Tissue laying on the lenses sometimes impaired the view although this was less of a problem in live supported bowel. Practically, it was difficult to maintain water in the GI tract for immersion endoscopy. Curved shape short focal length lenses gave the best images overall. Conclusion: Despite some limitations airless endoscopy was able to give high quality images of the small bowel and oesophagus. Better than expected views could also be obtained in the stomach and large bowel but were limited by the diameter of the viscus. Problems with illumination with internal reflection were encountered and resolved.

3486 A new device for endoscopic submucosal resection.

Background: There is a need for better control of endoscopic submucosal resection which is a minimally invasive method for removing small tumors, cancers or areas of dysplasia from gut mucosa or submucosa. It might also have an application in the treatment of Barratt s esophagus. Snare electrodiathermy injury patterns are often deeper than appreciated and saline injection though protective can be unpredictable. It is currently limited by difficulty in controlling the depth of the cut and by a consequent high risk of perforation. Our aim was to develop endoscopic devices which facilitate endoscopic submucosal resection to predetermined depths and decrease the risk of perforation. Methods : A device was constructed which could be mounted on the tip of an endoscope and arranged so that none of the functions were impaired and the field of endoscopic view was unimpaired in 3 out of 4 quadrants. The device featured a cavity into which tissue could be sucked. By adjusting the floating floor the depth of a tissue sucked into the cavity could be altered and different size resection capsules were constructed to fit the size of the tumor to be resected.Various methods of cutting of tissue were studied in combination with this instrument. Snare diathermy was designed to open in a rim of this cavity. (Shearing and blade cutting were also studied). The device was designed to be used in combination with endoscopic ultrasound and to incorporate a probe ultrasound transducer and allow real-time imaging of the tissue as the tumour is resected to a predetermined depth to ensure complete removal and avoid perforation. This device was tested on submucosal tumors created in postmortem stomach, oesophagus, colon. (Preliminary studies were performed in survival studies in pig.) Results : Artificial tumors were created by submucosal injection of saline, glues(including cyanoacrylate) and mucosa raised with elastic bands. The device successfully resected artificially produced submucosal and mucosal tumors at varying depths according to the adjustment of the floor of the suction cavity. When the device was used to remove small submucosal tumors created in post-mortem stomach perforation occurred 8/10 with the cavity depth set at 8mm, and 1/10 with the depth set at 5mm (p

3334 Hydrogels and other lubricants in endoscopy.

Background: Lubrication is commonly used in endoscopy despite little data on efficacy. Hydrogels are polymers, which when bonded to surfaces and wetted, become very effective lubricants. Hydrogels are biocompatible and could make very effective endoscopic lubricants. Aims: To measure the static and dynamic coefficient of friction of freshly excised porcine colonic tissue, using different lubricants including hydrogels, on the shaft of a colonoscope. Methods: The shaft of the endoscope was curved to form rails held in place by a wooden jig. A toboggan of known weight was constructed with colonic tissue stretched on the underside to run on the rails. The jig was tilted using a rotary table and control unit which allowed accurate measurements of the angles at which the toboggan started to move and the angle required to keep the toboggan moving using water, KY jelly, silicone spray and spray oil lubricants. Hydrogel measurements were made using hydrogel coated urinary catheters as the rails. Coefficient of friction was calculated for the different lubricants. Results: The static and dynamic coefficient of friction were difficult to measure for the lubricants other than hydrogels due to their viscosity resulting in very slow movements. The values for KY, silicone and oil were generally less than water, though not significantly. The static coefficient of friction was reduced by a factor of 6 for hydrogels and by a factor of 10 for dynamic coefficient of friction over all other lubricants. These results were significant(p

3495 Esophageal dilatation-how hard do you push?

Background: Little is known about the forces exerted during esophageal dilatation. The complications of which are discomfort and perforation, and relate to the forces applied to the dilator. We aimed to measure these forces. Methods: A device was designed and tested which measured the forces exerted on 13mm and 18 mm diameter thermoelastic Celestin bougies. The device took the form of a hinged split cylinder which can grip the dilator and measure forces imparted by the endoscopists hand. The split cylinders incorporated strain gauges that measure push and pull forces. The device was calibrated and used to measure the forces applied to the dilator during 17, over the guide-wire dilatations. The device was optically isolated and tested by the hospital s medical equipment department. Results: 12 dilatations were for esophageal malignancy, 2 for dysphagia post Nissen fundoplication and 3 for peptic strictures. Peak forces varied from 0.4-3.8Kg force(mean 1.73Kg force) for dilating malignancy,0.8-1.3Kg force(mean 1.05Kg force) post Nissen fundoplication and 0.7-1.4Kg force(mean 1.1Kg force) for peptic strictures. Mean peak force for the 13 and 18mm dilator was 1.46 and 1.61Kg force respectively. The degree of dysphagia did not correlate with the size of dilator used or force required for dilatation. There were no complications and of the 12 patients questioned post procedure, all reported some improvement in their dysphagia. Conclusions: This device was successfully used to measure accurately forces imparted to the bougie during esophageal dilatation. Clinical diagnosis did not seem to significantly affect the force required for dilatation in this series, but the forces required varied widely with individual patients. Further assessment could be helpful in defining safe forces to use and as an aid in teaching.

7033 Electrophysiological factors influencing broad based snare polypectomy.

Background: Analogue computer techniques were applied to measure power delivered and assess electrophysical factors influencing broad based polypectomy. Methods: Total energy, cutting time and tissue effect were measured during snare polypectomy cuts using polyp models formed in porcine gastric tissue as well as 7 and 11mm polyp stalks fashioned from post mortem porcine muscle. Constant forces were applied to close the snares. The high frequency generator used was the Erbotom ICC 200 on it s CUT(1-4), ENDOCUT(a sequential blend of CUT 1-4 and Soft COAG) and COAG(Soft and Forced) settings. Results: FCOAG waveforms required more power to initiate polyp model cutting than ENDOCUT or CUT on all settings (p