Prone Position Is Useful in Thoracoscopic Enucleation of Esophageal Leiomyoma oleh Kenji Maki, Shinsuke Takeno, Satoshi Nimura, Ippei Yamana, Hideki Shimaoka, Tatsuya Hashimoto, Ryousuke Shibata, Hironari Shiwaku, Kanefumi Yamashita, Yuichi Yamashita