Assessment of the Subarcuate Canaliculus as a Landmark in Middle Fossa Surgery.

Area of Science:

• Neurosurgery
• Otolaryngology
• Anatomy

Background:

• The middle fossa approach is crucial for internal auditory canal (IAC) lesion surgeries.
• Accurate localization of the superior semicircular canal (SSCC) is vital for safe drilling of the postmeatal triangle.
• The arcuate eminence, the current landmark for the SSCC, has a variable relationship with the SSCC.

Purpose of the Study:

• To evaluate the subarcuate canaliculus (SAC) as a potential landmark for localizing the SSCC.
• To enhance the safety of drilling the postmeatal triangle during IAC exposure.

Main Methods:

• Sixteen cadaveric temporal bone specimens were analyzed.
• An extradural middle fossa approach was performed.
• The subarcuate canaliculus (SAC), internal auditory canal (IAC), and superior semicircular canal (SSCC) were identified and dissected.

Main Results:

• The SAC was consistently identified, originating medially and extending postero-laterally towards the SSCC.
• The SAC's mean length was 10.9 mm, with a mean superior turn of 42° at its turning point.
• Avoiding drilling lateral to the SAC's turning point protected the SSCC and optimized posterior IAC dural exposure.

Conclusions:

• The subarcuate canaliculus (SAC) serves as a dependable ancillary landmark for SSCC localization.
• Integrating the SAC with the arcuate eminence enhances the safety of SSCC identification during IAC surgery drilling.