Variability in facial-muscle innervation: A comparative study based on electrostimulation and anatomical dissection.

Area of Science:

• Anatomy
• Neurosurgery
• Facial Nerve Anatomy

Background:

• Facial nerve palsy is a common complication of facial surgery.
• Detailed reports on facial nerve terminal branch distribution and communicating branches are scarce.

Purpose of the Study:

• To assess the variability of communicant and terminal branches of the human facial nerve.
• To identify anatomically risky areas during facial surgery.

Main Methods:

• Prospective study involving anatomical dissections (n=30) of extracranial facial nerve branching.
• Intraoperative electrical stimulation of facial nerves during parotidectomies (n=14).
• Analysis of electrostimulation and facial-neck movements by independent reviewers.

Main Results:

• Significant variability was found in the peripheral branching and intercommunication of facial nerve branches.
• Frontalis, depressor labii inferioris, and platysma muscles showed limited nerve recuperation.
• Sphincter muscles (orbicularis oris and oculi) were found to be anatomically protected.
• Individual differences in facial muscle innervation and complex variations in facial branching modes were observed.

Conclusions:

• Facial nerve branching patterns exhibit significant individual variability.
• Specific branches and areas are identified as anatomically risky during facial surgery.
• This variability impacts facial muscle innervation and necessitates careful surgical planning to avoid facial nerve palsy.