64 Facial Reanimation Flashcards
Briefly describe the course of the facial nerve.
Briefly describe the course of the facial nerve.
The facial nerve exits the brainstem, courses through the cerebellopontine angle, and then enters the temporal bone. After a complex course through the temporal bone, it exits the stylomastoid foramen and branches within the parotid gland into two main branches, the temporofacial and cervicofacial, at the pes anserinus. Traditionally, five terminal branches are present, including the temporal, zygomatic, buccal, marginal mandibular, and cervical.
What is the most commonly used classification of facial nerve injury?
What is the most commonly used classification of facial nerve injury?
The House-Brackmann Grading Scale is the most commonly used in the literature. House and Brackmann staged injury from grade 1 to 6 (Table 64-1). Increasing grade corresponds to a decreasing likelihood of spontaneous recovery.
What is synkinesis, and what is the first-line treatment for this disorder?
What is synkinesis, and what is the first-line treatment for this disorder?
Synkinesis is the hyperkinetic, uncoordinated mass facial movement seen with aberrant regeneration of nerve fibers after facial nerve injury. This involuntary synkinesia often occurs between the orbicularis oculi and orbicularis oris muscles, or presents as increased lacrimation of the affected eye. Currently, botulinum toxin injection is the first-line therapy. Botulinum toxin blocks the presynaptic release of acetylcholine causing a temporary functional denervation, thus limiting the synkinesis.
What key elements of the history and physical exam must be taken into account when approaching the patient with facial nerve paralysis?
What key elements of the history and physical exam must be taken into account when approaching the patient with facial nerve paralysis?
It is important to consider the patient’s medical history, mechanism of injury, presumed site of injury, timing of injury, vestibulocochlear function, eye closure, and individual expectations.
What is the role of electrodiagnostic testing following facial paralysis?
The goal of electrodiagnostic testing is to evaluate the degree of facial nerve injury and the functionality of the facial musculature. Commonly utilized electrical tests are the maximum stimulation test (MST), the nerve excitability test (NET), electroneuronography (ENOG), and electromyography (EMG).
Discuss electromyography (EMG) testing and how it is useful in the setting of facial reanimation.
EMG is the study of depolarization potentials in a muscle fiber. In the patient with facial paralysis, an EMG provides important information that can help determine appropriate treatment options. Typically, resting muscle exhibits no spontaneous electrical activity. In the setting of denervation from facial nerve injury, electrical activity may be increased, and spontaneous fibrillation potentials develop. Fibrillation potentials are strong evidence that denervation has occurred. Conversely, polyphasic action potentials indicate that regeneration is occurring.
Discuss electromyography (EMG) testing and how it is useful in the setting of facial reanimation.
Discuss electromyography (EMG) testing and how it is useful in the setting of facial reanimation.
EMG is the study of depolarization potentials in a muscle fiber. In the patient with facial paralysis, an EMG provides important information that can help determine appropriate treatment options. Typically, resting muscle exhibits no spontaneous electrical activity. In the setting of denervation from facial nerve injury, electrical activity may be increased, and spontaneous fibrillation potentials develop. Fibrillation potentials are strong evidence that denervation has occurred. Conversely, polyphasic action potentials indicate that regeneration is occurring.
Is there a role for physical therapy in facial reanimation?
Is there a role for physical therapy in facial reanimation?
Yes. Physical therapy is often underutilized in the setting of facial nerve paralysis. Facial neuromuscular reeducation using surface EMG and biofeedback techniques has demonstrated improvements in facial movement in randomized trials.
What is a potential sequela of paralysis of the orbicularis oculi?
What is a potential sequela of paralysis of the orbicularis oculi?
Paralysis of the orbicularis oculi muscle may result in incomplete eye closure, or lagophthalmos. Left untreated, paralytic lagophthalmos can lead to exposure keratitis, corneal ulceration, and blindness.
Describe broadly the types of surgical rehabilitation utilized for facial paralysis.
Describe broadly the types of surgical rehabilitation utilized for facial paralysis.
Surgical techniques for the management of facial paralysis can be classified as either static or dynamic. Static procedures serve to restore symmetry and limit functional sequela, but generally do not restore facial movement or tone. Dynamic procedures aim to restore movement and can be subdivided into neural procedures (cable grafting, cross-facial nerve grafting, XII to VII, V to VII), microvascular free flaps (gracilis flap), or other dynamic procedures (transposition of the temporalis or masseter, and temporalis tendon transfer).
Discuss treatment of the lower eyelid in the setting of facial paralysis.
Discuss treatment of the lower eyelid in the setting of facial paralysis.
The decision to treat or not largely depends on lower lid laxity, which can be assessed by the snap test. Medial lower lid laxity can cause the inferior punctum to evert from the globe and result in epiphora. Correction is with a medial canthoplasty. For excess lateral lower lid laxity, producing scleral show or ectropion, a horizontal lid shortening procedure is indicated.
What is ectropion?
What is ectropion?
Ectropion is the abnormal eversion of the lower eyelid in relation to the globe and can be associated with lower eyelid paralysis.
Discuss treatment of the paralyzed upper eyelid.
Discuss treatment of the paralyzed upper eyelid.
Gold weight implantation is the most popular procedure for managing upper eyelid paralytic lagophthalmos. Gold or platinum are often used because of their low reactivity and high density. The procedure can often be performed under local anesthesia, and is reversible. Since the procedure results in lid loading and is gravity dependent, it can lead to undesirable lid closure when lying supine.
In situations where the facial nerve was transected or resected, what is the technique of choice for repair?
In situations where the facial nerve was transected or resected, what is the technique of choice for repair?
Regardless of cause, primary nerve anastomosis, in the acute setting, is the technique of choice for repair of a completely disrupted facial nerve. Repair should occur as early as possible, ideally prior to Wallerian degeneration (within 72 hours). Success is largely dependent on the ability to reapproximate the disrupted segments without tension. Obtaining a tensionless repair may require mobilization or rerouting of the adjacent facial nerve segments.
What are some alternative options to repair a transected facial nerve when a tension-free reapproximation is not possible?
What are some alternative options to repair a transected facial nerve when a tension-free reapproximation is not possible?
For situations in which a tension-free reapproximation is not possible, one can utilize an interposition nerve graft. The two most popular nerves utilized for this purpose are the great auricular and sural nerves.
When counseling patients in terms of House-Brackmann score after a primary neurorrhaphy or interposition graft facial nerve repair, what is the best possible outcome?
When counseling patients in terms of House-Brackmann score after a primary neurorrhaphy or interposition graft facial nerve repair, what is the best possible outcome?
House-Brackmann Grade III (see Table 64-1).
What is cross-facial nerve grafting?
What is cross-facial nerve grafting?
Cross-facial nerve grafting is a two-stage procedure whereby the functioning facial nerve and its branches are used to innervate contralateral paralyzed nerve branches by way of an interposition graft. The first stage involves identifying distal facial nerve branches (buccal and zygomatic) on the normally functioning side and coapting a sural nerve graft to these. The second stage, undertaken 9 to 12 months later, is comprised of secondary neurorraphies between selected paralyzed facial nerve branches and the cross-face nerve graft. This procedure relies on a contralateral, normal-functioning nerve, and functional motor endplates on the paralyzed side. For this reason the period of degeneration ideally should be less than 6 months (Figure 64-1).
