ITナイフ2による食道ESD

Esophageal Endoscopic Submucosal Dissection with IT Knife 2

要旨　ITナイフは胃ESDで頻用されているが，食道ESDでは使用頻度が低い．主な理由として，① 食道は壁が薄く，ITナイフに特徴的な操作である“引き切り"操作を胃と同様の感覚で行うと容易に穿孔する，② ITナイフは縦方向の切開能は高いが，食道のような狭い管腔内では横方向への切開が困難である，などがあり，食道ESDには先端系デバイスが選択されることが多い．ITナイフ2（IT-2）は従来型の欠点を補う形で開発され，胃ESDでは良好な成績が報告されている．食道においても，IT-2の特性を理解し適切な操作を習得することで，安全かつ切除時間の短いESDが可能となる．本稿では，IT-2による食道ESDのコツと注意点を中心に述べる．

　Although Insulation-tipped diathermic knife（IT）is the major electrosurgical device used for ESD of gastric cancer, it is less used in cases of esophageal cancer. The major reasons are ; ① The esophageal wall is so thin that it is likely to perforate if IT is handled in the same way as in gastric cases, ② Although IT is suitable for longitudinal mucosal incision, it doesn't work well for lateral incision in the narrow esophageal lumen. Therefore, devices without an insulation tip such as the Hook knife,Flex knife, or Flush knife are often selected as the main device for esophageal ESD.

　IT knife 2（IT-2）has been developed to compensate for the weakness of IT and good therapeutic results have been reported in gastric cancer. By understanding the characteristics and appropriate handling of IT-2, it is possible to perform a safe and quick ESD even for esophageal cases. Knacks and pitfalls in esophageal ESD with IT-2 are described in this article.