The stylomastoid area: anatomic-histologic study and surgical approach

Area of Science:

• Neurosurgery
• Anatomy
• Surgical Technique

Background:

• Dissecting the facial nerve through mastoid tip soft tissues presents surgical challenges.
• Understanding the precise anatomical and histological relationships is crucial for safe nerve manipulation.

Purpose of the Study:

• To explore the anatomical and histological characteristics of the mastoid tip relevant to facial nerve dissection.
• To refine a surgical technique for safe facial nerve dissection in this region.

Main Methods:

• Anatomical measurements of the facial nerve relative to surrounding structures (digastric muscle, external canal, parotid bifurcation) in 20 specimens.
• Histological examination of the nerve sheath and mastoid tip fascial tissues in 10 specimens to assess tissue adherence.
• Application of findings to refine dissection techniques on cadaver specimens.

Main Results:

• Established average distances: facial nerve to digastric muscle (9 mm), external canal (11 mm), and parotid bifurcation (21 mm) at the stylomastoid foramen.
• Identified tight adherence between the facial nerve sheath and mastoid tip fascial fibers, hindering easy separation.
• Developed and tested a refined dissection technique based on the gathered anatomical and histological data.

Conclusions:

• The study provides critical anatomical and histological data for understanding facial nerve relationships in the mastoid tip.
• A refined surgical technique for safe facial nerve dissection through mastoid tip tissues was developed and validated.
• The refined technique demonstrated success in cadaveric dissections, offering potential for improved clinical application.