外傷診療の現場における臨床研究では, 群間の既知のバイアスを制御してアウトカム比較する観察研究が主流とならざるをえない. ただし, 科学的信憑性を確保するためには, 多くのサンプルサイズが要求されるし, 解析方法の技巧度も高くなる宿命にある. また, 既知のみで未知のバイアスを制御できないこと自体が, 観察研究の限界でもある. このような制約の中, 外傷診療を日夜担っている医師が観察研究を始めようとした際に, その敷居を低くし, かつ高い信憑性を確保するためのポイントについて, 把握しやすいよう本総説にまとめてみた. ここで指摘する点は初歩的なものばかりであるが, 数式で統計学を理解するには半年以上の月日がかかるであろう. そこで, これらの要点をまずは観察研究を行うためのお作法としてある程度鵜呑みにし, とにかく研究を始めてみることお勧めする. 統計理論は後まわしでよく, 結果を解釈する過程で理解も深まってくると思われる.

　　The new classification for trauma surgeons, the 2008 classification of organ injury, was explored by the Committee of Classification of Organ Injury in the Japanese Association for the Surgery of Trauma (JAST). The 2008 classification of organ injury was revised from the former classification of organ injury proposed by JAST from 1997 to 2000, and was improved by advances in diagnostic imaging and treatment, including surgical intervention. The results of questionnaire to a regular member of JAST, and to the critical care center, or to the hospital submitting data to the Japan Traumatic Date Bank (JTDB), has proved that the classification has been used commonly among trauma surgeons.

　　The classification of traumatic brain injury was proposed by JAST and the Japan Society of Neurotraumatology (JSTN). The classification was established by the combination of the classification of head injury by Gennarelli, the Japanese advanced trauma evaluation and care (JATEC), and the guidelines for the treatment and management of severe head injury by JSNT. Cases with impending cerebral herniation signs based on neurological findings and by CT imaging were defined as severe, and are treated by neurosurgery and/or by neurosurgical ICU.

　　These new classifications are expected to be used by trauma surgeons working in the emergency room.