PROBLEM TO BE SOLVED: To easily secure a surgical field as the operator desires, flexibly secure and change a surgical field according to a surgical site and a surgical situation, and to move a surgical site to a required position or Facilitate post-operative removal. A retractor (1) for maintaining a surgical field by holding a retractor in the body open in small incision endoscopic surgery, which is a thin sheet made of tin having a purity of 99.9% or more It includes an elongated rectangular base 2 in the folded state. It can be inserted into the body through a small incision in the form of a rectangularly-folded or small-rounded form and can be easily carried by a surgical instrument to a wound site in the body. By bending the surgical instrument into a required shape and applying it to a retractor in the body, the retractor can be held in an open state so as to secure a surgical field. Since the base 2 is made of tin having a purity of 99.9% or more, the base 2 can be easily bent and deformed into a desired form by using a surgical instrument because it is particularly flexible.【課題】術者の思うような術野の確保が容易であり、術部や手術状況に応じた術野の確保及び変更をフレキシブルに行うことができるとともに、術部の所要位置までの移動や術後の取出しを容易にする。【解決手段】小切開鏡視下手術において体内の開創部を開いた状態に保持して術野を確保する開創器１であって、純度９９．９％以上の錫製の薄板であり、伸ばした状態で細長い矩形状の基体２を含む。矩形状に伸ばした形態又は小さく丸めた形態で小切開創から体内へ挿入して、手術器具で体内の開創部まで容易に運ぶことができる。手術器具で所要形状に曲げ変形させた形態にして体内の開創部にあてがうことにより、術野を確保するように前記開創部を開いた状態に保持できる。基体２が純度９９．９％以上の錫製であることから、特に柔軟性が高いので、手術器具を用いて基体２を所要の形態に容易に曲げ変形させることができる。
