Tu1594 Technical Aspects of Endoscopic Removal of Stents Placed for Benign Esophageal Diseases

Tu1594 Technical Aspects of Endoscopic Removal of Stents Placed for Benign Esophageal Diseases Emo E. Van Halsema*, David E. Fleischer, Louis-Michel Wong Kee Song, Todd H. Baron, Peter D. Siersema, Frank P. Vleggaar, Gregory G. Ginsberg, Pari M. Shah, Shiva K. Ratuapli, Paul Fockens, Giacomo Rando, Alessandro Repici, Jeanin E. Van Hooft Gastroenterology & Hepatology, Academic Medical Center, Amsterdam, Netherlands; Gastroenterology & Hepatology, Mayo Clinic, Scottsdale, AZ; Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN; Gastroenterology & Hepatology, University Medical Center, Utrecht, Netherlands; Gastroenterology & Hepatology, Hospital of the University of Pennsylvania, Philadelphia, PA; Digestive Endoscopy, Istituto Clinico Humanitas, Rozzano, Italy Introduction: Temporary self-expandable stent placement has become a common strategy for the treatment of refractory benign esophageal strictures and fistulae. Fully covered self-expandable metal stents [FCSEMS], partially covered selfexpandable metal stents [PCSEMS] and self-expandable plastic stents [SEPS] are used for this purpose. Several techniques have been described for retrieval of stents once their therapeutic role has been fulfilled or because of complications, but data on efficacy and safety regarding various stent removal techniques are limited. Aims & Methods: Our aim was to describe endoscopic techniques and outcomes related to esophageal stent removal, taking into account different stent types and clinical settings: after therapy [AT], after migration [AM], after imbedding [AI] and miscellaneous [MI]. A multicenter retrospective chart review was performed from May 2002 to August 2011 which included 6 tertiary care centers from the U.S. and Europe. Results: A total of 312 stents were removed for which the retrieval techniques were known. Indications for stent placement included benign strictures (n 152; 48.7%) and fistulae (n 153; 49.0%). Types of stents removed were 164 (52.6%) FCSEMS, 86 (27.6%) PCSEMS and 62 (19.9%) SEPS, and the mean (median) dwell times were 62 (45.5), 46 (25), and 83 (49.5) days, respectively. The clinical context for stent removal was: AT in 196 (62.8%), AM in 86 (27.6%), AI in 15 (4.8%), and MI in 15 (4.8%), with the latter including mainly stent-induced fistulae (n 8) and stenoses (n 4). For the AT group, 190 (96.9%) stents, including 105 (64.0%) FCSEMS, 53 (61.6%) PCSEMS and 32 (51.6%) SEPS, were removed by traction using a grasping forceps [GF], causing 3 major and 22 minor complications in 6/105 (5.7%), 14/53 (26.4%) 5/32 (15.6%) cases, respectively. For the AM group, 78 (90.7%) stents, including 42 (25.6%) FCSEMS, 11 (12.8%) PCSEMS and 25 (40.3%) SEPS, were removed with a single GF and 6 (7.0%) were snare-assisted, all uncomplicated. For the AI group, 12 (80.0%) stents, including 11 (12.8%) PCSEMS and 1 (0.6%) FCSEMS, were removed using the stent-in-stent technique (7 biodegradable stents, 4 FCSEMS and 1 SEPS were used as second stents). Both stents were removed as one using a GF after a mean dwell time of 12 days (range 6 21), causing 2 minor bleedings. For the MI group, stent removal of 9 (5.5%) FCSEMS, 3 (3.5%) PCSEMS and 3 (4.8%) SEPS was all performed with a GF, resulting in 1 minor and 1 major complication. Conclusions: Self-expandable stents placed for benign esophageal diseases can be removed safely and effectively. For the AT and AM groups, the primary technique for endoscopic stent removal of FCSEMS, PCSEMS and SEPS was by traction with a grasping forceps. The stent-in-stent technique facilitates removal when a SEMS is found imbedded by granulation tissue. Tu1595 Esophageal Self-Expandable Metal Stents Material and Mesh Grid Density Are the Biggest Determinants of Radiation Dose Enhancement in the Setting of Esophageal Radiotherapy Barham K. Abu Dayyeh*, James J. Vandamme, Robert C. Miller, Todd H. Baron Gastroenterology and Hepatology, Mayo Clinic, Rochester, Rochester, MN; Radiation Oncology, Mayo Clinic, Eau Claire, WI; Radiation Oncology, Mayo Clinic, Rochester, MN Background: With the continued increase in the incidence of esophageal neoplasia the use of self-expandable metal stents (SEMSs) as an adjunct to chemoradiation for the treatment and palliation of malignant esophageal neoplasia continues to rise. The optimal esophageal stent design and material to minimize radiation dose enhancement and post-radiation complications in this setting is unknown. Aims: We aimed to quantify perturbation of intended radiation dose among the majority of available esophageal stents worldwide. Methods: We used an ex-vivo dosimetric film model to quantify perturbation of intended radiation dose among 11 different stents with varying materials and stent mesh designs: One stainless steel stent, one cobalt alloy stent, 7 nitinol stents, and two polymer based stents one of which is biodegradable. We quantified the radiation dose enhancement as the standard difference in the mean of intended radiation dose at three energy levels (6, 10, and 18 megavolts). Results: The radiation dose enhancement due to backscatter from esophageal stents ranged from 0% to 7% representing a standard difference in intended mean radiation dose of 1.8 (95th % CI 1.3 2.2). The radiation dose enhancement was negligible for the polymer based stents and approached 0% for the biodegradable one. In contrast, all metal alloy stents had significant radiation backscatter that was largely determined by the density of their mesh design not by the type of metal alloy used. The metal stent with the most dense mesh design had the highest radiation perturbation (standard difference in mean intended radiation dose of 3.7, 95th % CI 1.7 5.8) compared to the metal stent with the least dense mesh design (standard difference in mean intended radiation dose of 1.5, 95th % CI 0.1 2.9). Conclusions: Polymer based SEMSs show no discernible dose enhancement from stent radiation backscatter compared to metal alloy ones. Among metal alloy stents, the density of the mesh grid is the largest determinant of the magnitude of backscatter. Stents characteristics should be considered when selecting the optimal stent for treatment and palliation of malignant esophageal stricture; especially when adjuvant or neo-adjuvant radiotherapy is planned.