Anatomical reasons for problems after neurectomy for blepharospasm: a study in cadavers

Area of Science:

• Anatomy
• Neurosurgery
• Ophthalmology

Background:

• Blepharospasm is a neurological movement disorder characterized by involuntary eyelid closure.
• Neurectomy, a surgical procedure involving nerve removal, is sometimes used to treat blepharospasm.
• Complications and recurrence after neurectomy suggest a need for better anatomical understanding.

Purpose of the Study:

• To clarify the anatomical mechanisms underlying complications and recurrence following neurectomy for blepharospasm.
• To investigate the innervation patterns of the orbicularis oculi muscle by facial nerve branches.

Main Methods:

• Dissection of the left facial nerves in 10 Japanese cadavers using a surgical microscope.
• Detailed examination of the temporal, zygomatic, and buccal branches innervating the orbicularis oculi muscle.

Main Results:

• The temporal, zygomatic, and buccal branches form a communicating plexus posterior to the orbicularis oculi muscle.
• The inferior buccal branch shows deep curvature in the lower cheek and has ramifications connecting to other facial muscles.
• Existing anatomical literature inadequately details orbicularis oculi denervation patterns.

Conclusions:

• Incomplete denervation of the orbicularis oculi, potentially due to intact inferior buccal branches, may lead to blepharospasm recurrence.
• Unintended denervation of other facial muscles, alongside the orbicularis oculi, could result in post-neurectomy complications.
• Precise anatomical knowledge of facial nerve branching is essential for effective blepharospasm neurectomy.