Elizabeth Rajan

3465 The durability of different solutions injected submucosally in a porcine model.

During endoscopic mucosal resection and polypectomy of sessile lesions an injected submucosal fluid cushion isolates the tissue prior to resection and reduces thermal injury, perforation, and hemorrhage. Aim: To investigate the efficacy of five different solutions in creating a durable submucosal esophageal fluid cushion in a pig model. Methods: Five groups of 5 pigs were studied. In each pig, six submucosal injections of 5 cc of a test solution were performed within the lower third of the esophagus. The time required for the elevated mucosa to flatten completely was recorded after each injection. The solutions used were: normal saline (NS), NS+epinephrine (NSE), dextrose 50% (D50), 10% glycerine/5% fructose in NS (G), and 1% rooster comb hyaluronic acid (HA). Statistical analysis was performed using analysis of variance (ANOVA). NS was used as the standard solution for comparative analysis. Results: The mean and median times (minutes) for each solution to dissipate are provided in the table below. Conclusions: 1. This study provides important and practical information on the durability of available solutions used to create a submucosal fluid cushion during endoscopic mucosal resection and polyectomy of sessile lesions. 2. Hyaluronic acid appears to be the ideal solution for a lasting submucosal cushion during prolonged procedures. 3. Dextrose 50% is superior to normal saline and serves as a practical alternative in terms of availabilty and cost.

3470 Widespread circumferential mucosectomy in the porcine esophagus–a pilot study.

Endoscopic mucosal resection (EMR) is a procedure growing in significance as an alternative to surgery in the treatment of gastrointestinal mucosal lesions. Current EMR techniques are limited to lesions measuring less than 2 cm. Aim: To demonstrate that widespread circumferential mucosectomy up to 5 cm in length can be performed using a stripping method. Method: Eight, 60 kg anesthetized pigs were studied. The distal 5 cms of the esophagus was injected with 50% dextrose to create a lasting submucosal protective cushion. A strip of mucosa approximating 5 cm in length from the esophagogastric junction and 1 cm in width was marginated along its length and proximal end using a porcelain ball-tipped needle knife and prototype teflon backed monopolar scalpel (Olympus America, Inc., NY). The proximal end once undermined was grasped using forceps and stripped off the submucosal cushion in a distal direction. The distal end was then resected using a needle knife from a retroflexed position. This was repeated sequentially until the distal esophagus was circumferentially denuded of mucosa. Four pigs were sacrificed immediately after the procedure while two each of the remaining four animals were followed for two and four weeks. Result: Complete widespread circumferential mucosectomy was achieved in five animals with an average of four strips removed per pig. The average strip length was 5.5 cm(range 5-6 cm) and width 0.9 cm(range 0.6-1.2 cm). There were no procedural complications in the five animals. Mucosectomy was incomplete in the first two animals as the technique of mucosal stripping evolved with another animal experiencing a perforation early in this learning curve. The animals sacrificed immediately post-procedure showed histologically intact muscularis propria with some preservation of the submucosa and minimal associated edema and cautery injury. Repeat endoscopy of the surviving animals (4) showed healing with moderate (1) to tight (3) strictures at both two and four weeks. Conclusion: 1. Widespread circumferential esophageal mucosectomy can be performed endoscopically using a true stripping technique with preservation of the muscularis propria. 2. This technology has exciting potential clinical applications especially in the treatment of Barretts esophagus. 3. The appropriate measures to prevent post-procedural stricture formation need to be further investigated and identified. (The Apollo Group: Sydney Chung, Peter Cotton, Christopher Gostout, Robert Hawes, Anthony Kalloo, Pankaj Pasricha, Thadeus Trus)

7040 A developmental endoscopy unit: paving the way for the future of endoscopy.

Endoscopy volumes continue to grow despite steady cut-backs in reimbursement. Significant physician and paramedical personnel time is needed to meet this growth providing less time for endoscopic research and development. AIM: To create an environment that facilitates endoscopic research and development. METHODS: A physician and paramedical personnel core group was assembled to include a director, lead gastrointestinal assistant, study coordinator, and research fellow. Dedicated space and equipment were provided. Contacts were established with industry to seek mutual areas of equipment, accessories, and technique development with an emphasis on confidentiality. A system of record keeping using the latest information technologies was established with a monthly and yearly reporting schedule for all activities. The working unit created was entitled the Developmental Endoscopy Unit (DEU). RESULTS: The DEU began operation on 8/1/98. The activities which evolved include: clinical research, prototype endoscope and accessory testing, animal research of new endoscopic techniques, the performance of complex clinical cases using cutting edge technology, and the invention of new equipment. The DEU physician endoscopist staff has grown from one to six. Planned personnel growth includes the addition of a gastrointestinal assistant and research coordinator. A total of 14 new research protocols were initiated the first year by the original core group. Projects include the study of high resolution and high magnification endoscopy, endoscopic anti-reflux methods, and tissue resection techniques. CONCLUSIONS: 1. Given the demanding pace of clinical endoscopy, it is possible to successfully assemble a working unit dedicated to promote the advancement of endoscopic care. 2. The DEU core group was able to efficiently establish a large number of both clinical and animal research projects. 3. The DEU structure enhanced communication and a developmental liaison with industry.