3)胃 (3)ESD ④ STフード（先端細径透明フード）

Endoscopic Submucosal Dissection Using Sodium Hyaluronate and Small-Caliber-Tip Transparent Hood

要旨　内視鏡的粘膜下層剝離術（ESD）は，病変粘膜の外側に切開を置き，粘膜下層を剝離して一括切除する画期的方法であるが，安全性はもとより切除後の病理学的検討が正しく行われるように質の高い標本を得る必要がある．当科では，十分な厚みが長時間持続するヒアルロン酸ナトリウム溶液を粘膜下層注入液に使用している．また粘膜下層の剝離の際は，フードを摂子のように用いて，切除する粘膜にカウンタートラクションをかけ，粘膜下層に潜って直視下に観察しながら剝離を行っている．このとき，狭い隙間や，小彎・後壁の病変に対しては，先端が細く，鉗子が中央から出てくるSTフードを用いるとさらに有用である．これらの工夫により，ガイドライン内病変はもとより，適応拡大病変においても高い一括切除率が得られている．

　Recently endoscopic submucosal dissection (ESD) is becoming a popular intervention for large superficial gastric cancers in Japan. Using this method, large superficial lesions can be resected in one piece. Accurate pathological examination of the resected specimens after therapy is one of the most important advantages in this method. Indeed, curability or the necessity for additional surgery can be evaluated more precisely.

　In order to improve the quality of dissection, we have devised several means to take better advantage of this method. Submucosal injection of sodium hyaluronate can make a long lasting mucosal protrusion which provides a safe distance from both the mucosa and the muscle layer. A small-caliber-tip transparent hood (ST hood) attached to the endoscope tip is useful for better visualization of the submucosal tissue by opening up the incised mucosa. This enables precise aiming and control of a needle knife at the targeted level of the tissue. Using this procedure, regardless of the size and location, early gastric cancers can be completely resected in one piece with a very high success rate. The procedure of ESD using sodium hyaluronate and an ST hood are described.