Deep facial infections of odontogenic origin: CT assessment of pathways of space involvement.

PURPOSE We investigated the pathways of spread of odontogenic infection in the facial and neck spaces. METHODS CT scans of 45 patients with extensive spread of odontogenic infection into the facial and neck spaces were analyzed to document pathways of spread. RESULTS Odontogenic infections arising in the mandible first spread upward, into the masseter and/or medial pterygoid muscles in the masticator space, and downward, into the sublingual and/or submandibular spaces, and then spread into the spaces or muscles adjacent to one or more of these locations. Infections from the masseter muscle spread into the parotid space to involve the temporalis and lateral pterygoid muscles. Infections from the medial pterygoid muscle spread into the parapharyngeal space to involve the lateral pterygoid muscle. Infections in the maxilla did not spread downward; instead, they tended to spread upward and superficially into the temporal and/or masseter spaces and deeply involve the lateral and/or medial pterygoid muscles in the medial masticator space. CONCLUSION CT may be useful to depict the extent of infection and to plan treatment of extensive odontogenic infection, which can be life threatening when therapy is ineffective.