Objective: Although the effectiveness of a transparent hood has been reported in various endoscopic procedures, there are only a few reports regarding the benefit of a transparent hood in endoscopic injection sclerotherapy(EIS). In the current study, we conducted a retrospective evaluation of the efficacy and long-term benefit of an oblique transparent hood on EIS. Methods: The transparent hood, manufactured by Olympus (MAJ295 or MAJ296), consisted of a reusable wide oblique distal attachment with rim. This hood was attached when the varix was fine (F0 or F1). In this retrospective study, a total of 201 patients were recruited, and 99 patients (designated as the "Hood Group") received this hood while 102 patients (designated as the "Conventional Group") did not. We compared the rate of intravariceal injection, enhanced supply vessels, variceal eradication, and recurrence between these two groups. Results: This transparent hood provided a better visual field, and there was no serious complication in any of the patients. Intravariceal injection rates in the Hood Group and Conventional Group were 73.9% (190/257) and 57.7% (146/253) respectively (p<0.01). The rates of enhanced supply vessels in the Hood Group and Conventional Group were 89.8% (89/99) and 72.5% (74/102) respectively (p<0.01). The rates of variceal eradication did not differ significantly. We also assessed the cumulative non-recurrence probability for up to 3000 days between the two groups. The Hood Group was statistically superior to the Conventional Group (p<0.01) Conclusion: The application of an oblique transparent hood method is safe and effective for intravariceal EIS. This hood contributes especially to reduction of the long-term recurrence probability.博士（医学）・乙第1365号・平成27年11月27
