Definition of a Safe Drilling Zone in the Mastoid: Anatomic Insights From CT-Based Facial Nerve Mapping

Key Points

• The research aims to establish safe drilling depth thresholds relative to the facial canal during mastoid surgery.
• Utilized non-contrast computed tomography (NCCT) for mapping anatomical features.
• Determined specific drill depth thresholds at incus, midpoint, and stylomastoid levels.
• Evaluated the reproducibility of the maps created.
• Identified safe depth limits: ≤15 mm at the incus, ≤11 mm at the midpoint, ≤10 mm at the stylomastoid level.
• Found that these thresholds enhance awareness of safe drilling during surgery.
• Suggested that standard landmarks may not always be reliable, making these mappings crucial.