Endonasal anatomy of the olfactory neural network: Surgical implications.

OBJECTIVES/HYPOTHESIS: Define the anatomic distribution of the olfactory filaments within specific mucosal regions of the nasal cavity. STUDY DESIGN: Cadaveric study. METHODS: Seventeen cadaveric specimens (34 sides) were dissected to study the anatomical distribution and density of olfactory fila within different regions of the nasal cavity. Olfactory fila were dissected retrogradely to their point of entry into the anterior cranial fossa through the cribriform plate. Anatomic relationships among various components of the olfactory system and their corresponding arterial supply were determined subjectively. RESULTS: The highest density of olfactory fila was found at the mucosa of the ethmoid roof and superior turbinates. Olfactory fila were found at regions not previously considered to be part of the olfactory system: lateral wall of the nose, ethmoidal bullae, and between the os sphenoidale and arc of the posterior choana. Furthermore, at the septum, 20% of the olfactory fila crossed contralaterally before exiting the nose. The anterior ethmoidal arteries were the primary blood supply to the olfactory epithelium. CONCLUSIONS: This study suggests that olfactory filaments extend beyond previously established boundaries. These findings may have clinical implications regarding oncologic resections and could serve as the foundation for the development of techniques that better preserve olfactory function. LEVEL OF EVIDENCE: NA Laryngoscope, 2473-2477, 2018.

Analysis of the far-medial transoral endoscopic approach to the infratemporal fossa.

OBJECTIVES/HYPOTHESIS: To demonstrate anatomic relationships of the far-medial transoral endoscopic assisted approach (FMT-EAA) to the infratemporal fossa (ITF) and define the corridor dimensions, surgical freedom, and limitations associated with this approach. STUDY DESIGN: Cadaveric study. METHODS: Twenty ITFs (10 specimens) were dissected with the assistance of 0 °, 30 °, and 45 ° rod-lens endoscopes. Image guidance was used to confirm and measure the corridors' structural boundaries and document the anatomical relationships encountered in this approach. RESULTS: Access to the ITF via the FMT-EAA can be divided into two secondary surgical corridors: the superomedial and inferolateral triangles, each of which provides access to different areas. The superomedial triangle is bounded medially by the lateral pterygoid plate and posterolateral maxillary sinus wall, superiorly by the greater sphenoid wing, and inferolaterally by the lateral pterygoid muscle. The inferolateral triangle is bounded superiorly by the lower head of the lateral pterygoid muscle, inferiorly by the medial pterygoid muscle, and laterally by the mandible. Using a standard 19-mm endoscope, the FMT-EAA achieves a mean surgical freedom of 231 mm and 161 mm in the vertical and horizontal planes, respectively. CONCLUSIONS: FMT-EAA adequately exposes critical structures of the ITF. This technique is a viable option for the management of selected ITF lesions, either alone or in combination with alternative minimally invasive approaches to the region. LEVEL OF EVIDENCE: NA Laryngoscope, 128:2273-2281, 2018.