外側後頭下開頭とfar lateral approach—神経鞘腫・髄膜腫・類上皮腫手術のための術野拡大

Lateral Suboccipital Retrosigmoid and Far Lateral Approaches:Various Extensions for Schwannoma, Meningioma, and Epidermoid Cyst Surgery

Point

・浅く広い術野を作るよう，体位・皮膚切開・筋層剝離を行う．

・Far lateral/transcondylar approachなどの開頭範囲の拡大の際は，アプローチの名称にとらわれることなく，症例に応じて大孔の開放や顆窩・頚静脈結節・後頭顆の削除などの手技を組み合わせる．

・側頭骨内部の解剖を十分に理解し，Meckel腔・内耳道後壁・頚静脈孔上壁の骨削除を行う．

・主要血管を温存しつつ脳裂の可及的剝離を行うことで，効果的な小脳の牽引が可能となる．

　The lateral suboccipital retrosigmoid approach is one of the most established approaches for accessing the posterior cranial fossa. In order to expand the surgical field, several extensions, including（1）extended craniotomy（e.g., far lateral, transcondylar, and transsigmoid approaches）, （2）additional intradural osseous or bony drilling（e.g., transmeatal and suprajugular approaches）, and （3）fissure dissection（e.g., suprafloccular and infrafloccular approaches）, have been described. In this report, we introduce our technique for the retrosigmoid approach and review several extensions as illustrated by schwannoma, meningioma, and epidermoid cyst surgeries.