Intracranial Anatomic Landmarks for Endoscopic Endonasal Transcribriform Approach to Anterior Skull Base.

OBJECTIVES: To help surgeons locating anatomic landmarks when performing endoscopic endonasal transcribriform approach to anterior skull base.

METHODS: High-resolution axial computed tomography (CT) images at thickness of 0.6 mm, and reconstructed 0.41-mm thick gapless sagittal and coronal CT images were taken from 123 subjects. Using mimics software, first located elementary points and line: nasal spine, midpoint of posterior hard palate and the line between them; then located measured points right/left posterior and anterior points; measured distances between measured points and from measured points to nasal spine and angles between lines connecting measured points to nasal spine and the basic line.

RESULTS: The distances from nasal spine to right/left posterior and anterior points of anterior skull base are 68.67 ± 6.04 and 61.71 ± 5.09 mm, corresponding angles are 45.89 ± 4.20° and 72.07 ± 4.06°, respectively. The width and length of defect of anterior skull base are 24.45 ± 2.62 and 31.03 ± 4.96 mm; its area ranges from 373.75 ± 94.08 to 800.91 ± 195.07 mm.

CONCLUSIONS: The study provides information about anterior skull base anatomic landmarks, which can help surgeons to locate them and avoid relative complications during endoscopic endonasal transcribriform approach to anterior skull base. The measurements can be used as surgical indicators to investigate the landmarks.