Facial nerve dissection in parotid surgery: a microscopic investigation study

Area of Science:

• Anatomy
• Surgical Anatomy
• Head and Neck Surgery

Background:

• Preserving the facial nerve during parotid surgery is critical.
• The anatomical basis for superficial and deep parotid gland divisions and surrounding facial nerve structures requires histological clarification.

Purpose of the Study:

• To histologically determine if anatomical superficial and deep lobes of the parotid gland exist.
• To elucidate the structures surrounding the facial nerve within the parotid gland.

Main Methods:

• Cadaveric parotid gland dissection and histological analysis.
• Serial sectioning of parotid tissue perpendicular to the facial nerve.
• Microscopic examination of nerve morphology, perineural tissue thickness, and dissection layers.

Main Results:

• The parotid gland is subdivided by a mesh-like interlobular connective tissue, not distinct lobes.
• The facial nerve courses within this interlobular connective tissue, not along a superficial-deep boundary.
• Perineural tissue thickness decreases distally, potentially complicating dissection.
• The surgical dissection plane is located within the perineural tissue.

Conclusions:

• Anatomical separation into superficial and deep parotid lobes is not supported by histological findings.
• The facial nerve is embedded within interlobular connective tissue throughout the parotid gland.
• Understanding perineural tissue characteristics is essential for safe facial nerve dissection in parotid surgery.