Predicting the presigmoid retrolabyrinthine space using a sigmoid sinus tomography classification: A cadaveric study

Area of Science:

• Neurosurgery
• Otolaryngology
• Anatomy

Background:

• The presigmoid retrolabyrinthine space exhibits significant size variability, primarily influenced by the sigmoid sinus.
• Existing classifications for sigmoid sinus position lack reliability in predicting this space.
• Accurate prediction is crucial for surgical planning in the petroclival region.

Purpose of the Study:

• To develop and validate a novel tomographic classification system for sigmoid sinus position.
• To assess the system's ability to predict the presigmoid retrolabyrinthine space in human cadavers.

Main Methods:

• Computed tomography (CT) scanning of 10 human cadaver temporal bones.
• Classification of sigmoid sinus position into medial and lateral groups based on a reference line.
• Comparison of surgical approaches and anatomical landmarks between groups via mastoidectomy.

Main Results:

• The medial group demonstrated a greater distance from the sigmoid sinus to the external auditory canal and a shallower lateral semicircular canal.
• The lateral group presented challenges during mastoidectomy, with a narrower Trautmann's triangle often obscured by the sigmoid sinus.

Conclusions:

• The proposed tomographic classification accurately predicts presigmoid retrolabyrinthine space in a cadaveric model.
• This classification can guide surgeons in selecting optimal surgical approaches for petroclival region access.
• Implementation may enhance safety in neurological and otological surgeries.