title: The Comprehensive AOCMF Classification: Skull Base and Cranial Vault Fractures - Level 2 and 3 Tutorial.
abstract: The AOCMF Classification Group developed a hierarchical three-level craniomaxillofacial classification system with increasing level of complexity and details. The highest level 1 system distinguish four major anatomical units, including the mandible (code 91), midface (code 92), skull base (code 93), and cranial vault (code 94). This tutorial presents the level 2 and more detailed level 3 systems for the skull base and cranial vault units. The level 2 system describes fracture location outlining the topographic boundaries of the anatomic regions, considering in particular the endocranial and exocranial skull base surfaces. The endocranial skull base is divided into nine regions; a central skull base adjoining a left and right side are divided into the anterior, middle, and posterior skull base. The exocranial skull base surface and cranial vault are divided in regions defined by the names of the bones involved: frontal, parietal, temporal, sphenoid, and occipital bones. The level 3 system allows assessing fracture morphology described by the presence of fracture fragmentation, displacement, and bone loss. A documentation of associated intracranial diagnostic features is proposed. This tutorial is organized in a sequence of sections dealing with the description of the classification system with illustrations of the topographical skull base and cranial vault regions along with rules for fracture location and coding, a series of case examples with clinical imaging and a general discussion on the design of this classification.
authors.affiliation: Division of Neurosurgery, St. Michael's Hospital, University of Toronto, Toronto, Canada.
authors.forename: Antonio
authors.initials: A
authors.lastname: Di Ieva
authors.affiliation: AO Clinical Investigation and Documentation, AO Foundation, Dübendorf, Switzerland ; Research and Development Department, Schulthess Clinic, Zürich, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Audigé
authors.affiliation: Department of Otolarynology-Head and Neck Surgery, SUNY Upstate Medical University, Syracuse, New York.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Kellman
authors.affiliation: Group Health Associates, Cincinnati, Ohio.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Shumrick
authors.affiliation: Department of Radiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Helmut
authors.initials: H
authors.lastname: Ringl
authors.affiliation: Clinic for Oral and Craniomaxillofacial Surgery, University Hospital Basel, Basel, Switzerland.
authors.forename: Joachim
authors.initials: J
authors.lastname: Prein
authors.affiliation: Department of Neurosurgery, Medical University of Vienna, Vienna, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Matula
keywords: classification system; cranial vault; fracture classification; skull base