Facial Nerve ParalysisFacial Nerve Paralysis

Melanie Giesler, DOMelanie Giesler, DO

AnatomyAnatomy

AnatomyAnatomy

The motor nucleus of the facial nerve lies deep The motor nucleus of the facial nerve lies deep within the reticular formation of the pons where it within the reticular formation of the pons where it receives input from the precentral gyrus of the receives input from the precentral gyrus of the motor cortex, which innervates the ipsilateral motor cortex, which innervates the ipsilateral and contralateral forehead. and contralateral forehead.

Cerebral cortical tracts also innervate the Cerebral cortical tracts also innervate the contralateral portion of the remaining face. contralateral portion of the remaining face.

Accounts for the sparing of the forehead motion Accounts for the sparing of the forehead motion in supranuclear lesions of the facial nerve in supranuclear lesions of the facial nerve

Differential DiagnosisDifferential DiagnosisAcute facial palsyAcute facial palsy

InfectionInfection– Herpes Zoster Oticus Herpes Zoster Oticus

(Ramsey Hunt Syndrome)(Ramsey Hunt Syndrome)– Lyme diseaseLyme disease– Acute Otitis media +/- mastoiditisAcute Otitis media +/- mastoiditis

CongenitalCongenital– Treacher Collins syndromeTreacher Collins syndrome– Mobius syndromeMobius syndrome

TraumaTrauma– Temporal Bone fractureTemporal Bone fracture– BarotraumaBarotrauma

MetabolicMetabolic- DiabetesDiabetes- HypothyroidismHypothyroidism

VascularVascular– Benign intracranial hypertensionBenign intracranial hypertension

NeoplasmNeoplasm– Facial neuromaFacial neuroma– Acoustic neuromaAcoustic neuroma

ToxicToxic– ThalidoideThalidoide

IatrogenicIatrogenic

Physiology of Nerve InjuryPhysiology of Nerve Injury

When an axon is injured, biochemical and When an axon is injured, biochemical and histological changes occur in the cell body histological changes occur in the cell body proximal and distal to the site of the injury. proximal and distal to the site of the injury. Severity of the changes depend upon:Severity of the changes depend upon:– distance from the injury to the cell body (proximal distance from the injury to the cell body (proximal

injuries usually more severe than distal injuries), injuries usually more severe than distal injuries), – type of injury (crush injuries more severe than clean type of injury (crush injuries more severe than clean

transections)transections)– age of the patient (older individuals sustain more age of the patient (older individuals sustain more

severe injury than younger patients)severe injury than younger patients)– nutritional and metabolic status of the patient. nutritional and metabolic status of the patient.

Sunderland classification of Sunderland classification of peripheral nerve injuryperipheral nerve injury

Neurapraxia

Axonotmesis

Neurotmesis

First DegreeFirst Degree

NeuropraxiaNeuropraxialocalized conduction block in the nerve localized conduction block in the nerve with the nerve fibers responding to with the nerve fibers responding to electrical stimuli proximal and distal to the electrical stimuli proximal and distal to the lesion, but not across the injured segment.lesion, but not across the injured segment. Axonal continuity is preserved, wallerian Axonal continuity is preserved, wallerian degeneration does not occur, and degeneration does not occur, and recovery is usually complete.recovery is usually complete.Arm “falling asleep” Arm “falling asleep”

Second DegreeSecond Degree

AxonotmesisAxonotmesisDisruption of the axon into proximal and distal Disruption of the axon into proximal and distal portions with interrupted axoplasmic flow.portions with interrupted axoplasmic flow. Wallerian degeneration occurs within 24 hours Wallerian degeneration occurs within 24 hours in the distal portion of the axon and to a slight in the distal portion of the axon and to a slight degree in the proximal portion. degree in the proximal portion. The connective tissue elements remain intact, The connective tissue elements remain intact, however, and the axon may regenerate at a rate however, and the axon may regenerate at a rate of 1 mm/day to the original end organ with the of 1 mm/day to the original end organ with the potential for complete recovery. potential for complete recovery.

Third DegreeThird Degree

EndoneurotmesisEndoneurotmesisEndoneurium and axon are destroyed, but the Endoneurium and axon are destroyed, but the perineurium remains intact. perineurium remains intact. Wallerian degeneration occurs. Wallerian degeneration occurs. Axons may regenerate, but can be blocked by Axons may regenerate, but can be blocked by scar tissue. scar tissue. This will result in partial reinnervation. In This will result in partial reinnervation. In addition, misdirection of fibers can occur with addition, misdirection of fibers can occur with resultant synkinesis (abnormal mass movement resultant synkinesis (abnormal mass movement of muscles which do not normally contract of muscles which do not normally contract together) and incomplete recovery. together) and incomplete recovery.

Fourth DegreeFourth Degree

PerineurotmesisPerineurotmesis

Only the epineurium remains intact, while the Only the epineurium remains intact, while the axon, endoneurium, and perineurium are axon, endoneurium, and perineurium are disrupted. disrupted.

Wallerian degeneration occurs, and there is Wallerian degeneration occurs, and there is much greater chance for aberrant regeneration, much greater chance for aberrant regeneration, synkinesis, and incomplete recovery. synkinesis, and incomplete recovery.

Analogy of cord with fibers inside broken but Analogy of cord with fibers inside broken but insulation portion remains intactinsulation portion remains intact

Fifth DegreeFifth Degree

NeurotmesisNeurotmesisComplete disruption of neural continuity. Complete disruption of neural continuity. Without careful repair, there is little to no chance Without careful repair, there is little to no chance of regeneration and recoveryof regeneration and recoveryAxonal sprouts may escape the confines of the Axonal sprouts may escape the confines of the nerve sheath and produce painful neuromas nerve sheath and produce painful neuromas adjacent to the injured nerve. adjacent to the injured nerve. Except in cases of complete transection, nerve Except in cases of complete transection, nerve injury is usually a combination of degrees of injury is usually a combination of degrees of injury. injury.

Clinical EvaluationClinical Evaluation

HistoryHistoryOnset of the paralysis (sudden vs delayed) Onset of the paralysis (sudden vs delayed) Duration, and the rate of progression. Duration, and the rate of progression. It is especially important to determine whether the It is especially important to determine whether the paralysis is complete verses incomplete.paralysis is complete verses incomplete.Patients should be questioned regarding Patients should be questioned regarding previous previous episodes, family history, associated symptomsepisodes, family history, associated symptoms (hearing loss, otorrhea, otalgia, vertigo, headaches, (hearing loss, otorrhea, otalgia, vertigo, headaches, blurred vision, parasthesias), blurred vision, parasthesias), associated medical associated medical illnessesillnesses (diabetes, pregnancy, autoimmune disorders, (diabetes, pregnancy, autoimmune disorders, cancer), history of trauma (recent or remote), and cancer), history of trauma (recent or remote), and previous surgeryprevious surgery (otologic, rhytidectomy, (otologic, rhytidectomy, parotidectomy). parotidectomy).

Physical ExaminationPhysical Examination

Complete head and neck examination must be Complete head and neck examination must be performed, including microscopic examination of performed, including microscopic examination of the ears, careful palpation of the parotid glands the ears, careful palpation of the parotid glands and neck, ophthalmologic examination (r/o and neck, ophthalmologic examination (r/o papilledema), auscultation of the neck ( r/o papilledema), auscultation of the neck ( r/o carotid bruits), and a thorough neurological carotid bruits), and a thorough neurological examination. examination. It is important to assess the degree of voluntary It is important to assess the degree of voluntary movement present in order to document the movement present in order to document the grade of facial paralysis as described in the grade of facial paralysis as described in the House classification system House classification system

House-Brackman Grading House-Brackman Grading SystemSystem

Central vs PeripheralCentral vs Peripheral

Supranuclear (central) lesions produce Supranuclear (central) lesions produce contralateral voluntary lower facial paralysis. The contralateral voluntary lower facial paralysis. The frontalis muscle is spared because of the frontalis muscle is spared because of the bilateral innervation as described previously.bilateral innervation as described previously. Emotional response (facial motion on laughing Emotional response (facial motion on laughing or crying) may also be preserved with central or crying) may also be preserved with central lesions. lesions. Presence of Bell's phenomenon (upward Presence of Bell's phenomenon (upward outward turning of the eyeball as the patient outward turning of the eyeball as the patient attempts to close the eyelids) indicates a attempts to close the eyelids) indicates a peripheral lesion. peripheral lesion.

Work UpWork Up

Any patient presenting with facial paralysis Any patient presenting with facial paralysis should undergo formal should undergo formal audiological testingaudiological testing, , including pure tone, air and bone conduction, including pure tone, air and bone conduction, speech discrimination, reflexes, and speech discrimination, reflexes, and tympanometry. tympanometry.

If asymmetry is found on the audiogram, an ABR If asymmetry is found on the audiogram, an ABR and/or and/or MRIMRI should be obtained. should be obtained. Electronystagmography (ENG)Electronystagmography (ENG) is usually not is usually not indicated unless vertigo or other balance indicated unless vertigo or other balance disturbance is part of the clinical picture. disturbance is part of the clinical picture.

Radiologic EvaluationRadiologic Evaluation

May be undertaken in patients with a May be undertaken in patients with a history of recurrent paralysis, associated history of recurrent paralysis, associated neurological symptoms, suspected CPA neurological symptoms, suspected CPA lesions, concurrent otologic findings lesions, concurrent otologic findings (AOM, COM, suspected cholesteatoma), (AOM, COM, suspected cholesteatoma), history of trauma, gradually developing history of trauma, gradually developing facial nerve paralysis, atypical facial nerve paralysis, atypical presentation, or if patients show no presentation, or if patients show no evidence of recovery after one month from evidence of recovery after one month from onset. onset.

Radiologic EvaluationRadiologic Evaluation

Gadolinium enhanced MRI is superior for soft Gadolinium enhanced MRI is superior for soft tissue evaluation and will usually reveal the tissue evaluation and will usually reveal the inflammation and edema associated with Bell's inflammation and edema associated with Bell's palsy and with Herpes Zoster oticus. It is also palsy and with Herpes Zoster oticus. It is also considered to be the procedure of choice to rule considered to be the procedure of choice to rule out a cerebellopontine angle tumor or other brain out a cerebellopontine angle tumor or other brain tumors. tumors. High- resolution computed tomography provides High- resolution computed tomography provides excellent bony assessment and is the study of excellent bony assessment and is the study of choice to rule out a temporal bone fracture, or to choice to rule out a temporal bone fracture, or to evaluate the middle ear and mastoid. evaluate the middle ear and mastoid.

Electrophysiologic TestingElectrophysiologic Testing

These tests are useful for patients with These tests are useful for patients with complete paralysis for determining complete paralysis for determining prognosis for return of facial function and prognosis for return of facial function and the endpoint of degeneration by serial the endpoint of degeneration by serial testing. testing.

They are most useful when considering They are most useful when considering decompression surgery and are of no decompression surgery and are of no value in patients with incomplete paralysis. value in patients with incomplete paralysis.

Electrophysiologic TestingElectrophysiologic Testing

Nerve excitability test (NET), maximal stimulation test Nerve excitability test (NET), maximal stimulation test (MST), and electroneuronography (ENoG) are most (MST), and electroneuronography (ENoG) are most useful in the degenerative phase. useful in the degenerative phase. These tests will give normal results during the first 72 These tests will give normal results during the first 72 hours after injury due to the stimulating and recording hours after injury due to the stimulating and recording electrodes both being distal to the site of the injury. electrodes both being distal to the site of the injury. After 3 - 4 days, the nerve degeneration reaches the site After 3 - 4 days, the nerve degeneration reaches the site of stimulation and useful results will be obtained. of stimulation and useful results will be obtained. These tests can only be used for unilateral paralysis These tests can only be used for unilateral paralysis because all three involve comparison to the contralateral because all three involve comparison to the contralateral side which must be normal for valid results. side which must be normal for valid results.

Nerve Excitability TestNerve Excitability Test

Nerve excitability test (NET) is the most commonly used secondary Nerve excitability test (NET) is the most commonly used secondary to the low cost, readily available equipment, and ease of to the low cost, readily available equipment, and ease of performance. performance. This test involves placement of a stimulating electrode over the This test involves placement of a stimulating electrode over the stylomastoid foramen. The lowest current necessary to produce a stylomastoid foramen. The lowest current necessary to produce a twitch on the paralyzed side of the face (threshold) is compared with twitch on the paralyzed side of the face (threshold) is compared with the contralateral side. A difference of greater than 3.5 milliamps the contralateral side. A difference of greater than 3.5 milliamps indicates a poor prognosis for return of facial function. indicates a poor prognosis for return of facial function. The major draw back to the use of this test is its subjectivity, with The major draw back to the use of this test is its subjectivity, with reliance entirely on a visual end point. In addition, since such a reliance entirely on a visual end point. In addition, since such a small amount of current is used with this test, a few intact axons small amount of current is used with this test, a few intact axons may give a visible response leading the clinician to predict a good may give a visible response leading the clinician to predict a good prognosis, when in reality most of the fibers are degeneratingprognosis, when in reality most of the fibers are degenerating

Maximum Stimulation TestMaximum Stimulation Test

Maximum stimulation test (MST) is a modified version of the NET. A Maximum stimulation test (MST) is a modified version of the NET. A maximal stimulus is used to depolarize all facial nerve branches. maximal stimulus is used to depolarize all facial nerve branches. The paralyzed side is then compared to the contralateral side and The paralyzed side is then compared to the contralateral side and the difference is graded as equal, slightly decreased, markedly the difference is graded as equal, slightly decreased, markedly decreased, or absent.decreased, or absent.Testing begins on the third day post onset and is repeated Testing begins on the third day post onset and is repeated periodically until return of facial function or absent response. An periodically until return of facial function or absent response. An equal or slightly decreased response on the involved side is equal or slightly decreased response on the involved side is considered favorable for complete recovery. considered favorable for complete recovery. An absent or markedly decreased response denotes advanced An absent or markedly decreased response denotes advanced degeneration with a poor prognosis. The response to this test degeneration with a poor prognosis. The response to this test becomes abnormal sooner than the response to the NET and is becomes abnormal sooner than the response to the NET and is therefore considered superior. However, like the NET, this test is therefore considered superior. However, like the NET, this test is also subjective. also subjective.

Electroneurography (ENoG)Electroneurography (ENoG)

Considered to be the most accurate prognostic test because it Considered to be the most accurate prognostic test because it provides an objective, qualitative measurement of neural provides an objective, qualitative measurement of neural degeneration. degeneration. The facial nerve is stimulated with an impulse transcutaneously at The facial nerve is stimulated with an impulse transcutaneously at the stylomastoid foramen using bipolar electrodes. The muscular the stylomastoid foramen using bipolar electrodes. The muscular response is then recorded using bipolar electrodes placed near the response is then recorded using bipolar electrodes placed near the nasolabial groove. The peak to peak amplitude of the evoked nasolabial groove. The peak to peak amplitude of the evoked compound action potential is considered proportional to the number compound action potential is considered proportional to the number of intact axons. of intact axons. The two sides are then compared with the response on the The two sides are then compared with the response on the paralyzed side of the face expressed as a percentage of the paralyzed side of the face expressed as a percentage of the response on the normal side of the face. A reduction in amplitude on response on the normal side of the face. A reduction in amplitude on the involved side to 10% or less of the normal side indicates a poor the involved side to 10% or less of the normal side indicates a poor prognosis for spontaneous recovery. A maximal reduction of less prognosis for spontaneous recovery. A maximal reduction of less than 90% within 3 weeks of onset gives an expected spontaneous than 90% within 3 weeks of onset gives an expected spontaneous rate of recovery of 80 - 100%. rate of recovery of 80 - 100%.

Electromyography (EMG)Electromyography (EMG)

Is of limited value early in the evaluation of facial paralysis because Is of limited value early in the evaluation of facial paralysis because fibrillation potentials indicating axonal degeneration do not appear fibrillation potentials indicating axonal degeneration do not appear until 10 to 14 days post onsetuntil 10 to 14 days post onsetEMG becomes important for assessing reinnervation potential of the EMG becomes important for assessing reinnervation potential of the muscle two weeks after onset. By using needle electrodes placed muscle two weeks after onset. By using needle electrodes placed transcutaneously into the muscles of facial expression, muscle transcutaneously into the muscles of facial expression, muscle action potentials generated by voluntary activity can be recorded. action potentials generated by voluntary activity can be recorded. Electrical silence can indicate normal muscle in a resting state, Electrical silence can indicate normal muscle in a resting state, severe muscle wasting and fibrosis or acute facial paralysis in the severe muscle wasting and fibrosis or acute facial paralysis in the early stages. During normal voluntary contraction organized early stages. During normal voluntary contraction organized diphasic or triphasic potentials are seen. diphasic or triphasic potentials are seen. Fibrillation potentials indicate degeneration of the neural supply to Fibrillation potentials indicate degeneration of the neural supply to the muscle in question. Polyphasic potentials indicate reinnervation. the muscle in question. Polyphasic potentials indicate reinnervation. These are important because they usually appear 6 - 12 weeks These are important because they usually appear 6 - 12 weeks before clinical return of function. before clinical return of function.

Bell’s PalsyBell’s Palsy

Bell's palsy is the most common cause of facial Bell's palsy is the most common cause of facial paralysis and accounts for more than half of all paralysis and accounts for more than half of all cases. Traditionally, this was considered to be a cases. Traditionally, this was considered to be a diagnosis of exclusion after ruling out all other diagnosis of exclusion after ruling out all other possible causes. possible causes. However, it has recently been considered a However, it has recently been considered a positive diagnosis if the following are present: positive diagnosis if the following are present: unilateral weakness of all facial muscles of unilateral weakness of all facial muscles of sudden onset, possibly associated with a viral sudden onset, possibly associated with a viral prodrome, no evidence of central nervous prodrome, no evidence of central nervous system pathology, no evidence of a CPA lesion, system pathology, no evidence of a CPA lesion, no history of otologic disease. no history of otologic disease.

Bell’s PalsyBell’s Palsy

Estimated to be 20 to 30 per 100,000, but Estimated to be 20 to 30 per 100,000, but appears to increase with age. appears to increase with age. There is an equal male to female ration and a There is an equal male to female ration and a 3.3 times greater incidence in pregnant females. 3.3 times greater incidence in pregnant females. The left and right sides of the face are equally The left and right sides of the face are equally involved, and less than 1% of cases are involved, and less than 1% of cases are bilateral. bilateral. The recurrence rate is about 10% and can be The recurrence rate is about 10% and can be ipsilateral or bilateral. Patients with diabetes ipsilateral or bilateral. Patients with diabetes have 4 - 5 times more risk of developing the have 4 - 5 times more risk of developing the disease. A family history is positive in about 10% disease. A family history is positive in about 10% of patients with Bell's palsy. of patients with Bell's palsy.

Bell’s PalsyBell’s Palsy

The most likely site of lesion in Bell's palsy is the meatal foramen The most likely site of lesion in Bell's palsy is the meatal foramen (junction of the internal auditory canal portion of the nerve and the (junction of the internal auditory canal portion of the nerve and the labyrinthine segment of the nerve), which is considered to be the labyrinthine segment of the nerve), which is considered to be the narrowest portion of the fallopian canal. narrowest portion of the fallopian canal. MRI with gadolinium will usually show enhancement of the MRI with gadolinium will usually show enhancement of the labyrinthine portion of the nerve. As the edema within the nerve labyrinthine portion of the nerve. As the edema within the nerve increases, axonal flow and circulation are inhibited resulting in increases, axonal flow and circulation are inhibited resulting in varying degrees of nerve injury (first, second, and third degree).varying degrees of nerve injury (first, second, and third degree).Patients who are most severely affected develop a high level of third Patients who are most severely affected develop a high level of third degree injury which can result in the loss of endoneural tubules and degree injury which can result in the loss of endoneural tubules and misdirected axonal regeneration. Histological studies from patients misdirected axonal regeneration. Histological studies from patients with Bell's palsy who died of nonrelated causes reveal diffuse with Bell's palsy who died of nonrelated causes reveal diffuse demyelination of the facial nerve with lymphocytic infiltrates demyelination of the facial nerve with lymphocytic infiltrates

Bell’s PalsyBell’s Palsy

The prognosis for Bell's palsy is generally good The prognosis for Bell's palsy is generally good with 85 to 90% of patients recovering completely with 85 to 90% of patients recovering completely within one month. within one month. The remaining 15% progress to complete The remaining 15% progress to complete degeneration and will not usually show signs of degeneration and will not usually show signs of recovery for three to six months. recovery for three to six months. The longer the time needed for recovery, the The longer the time needed for recovery, the greater the probability of sequelae. greater the probability of sequelae. The single most important prognostic factor is The single most important prognostic factor is the degree of paralysis. Patients with incomplete the degree of paralysis. Patients with incomplete paralysis will recover with no sequelae 95% of paralysis will recover with no sequelae 95% of the time the time

Bell’s PalsyBell’s Palsy

Patients may exhibit evidence of concomitant Patients may exhibit evidence of concomitant sensory cranial polyneuritis with otalgia or sensory cranial polyneuritis with otalgia or postauricular pain, dysacousis or hyperacusis, postauricular pain, dysacousis or hyperacusis, dysgeusia, decreased tearing or epiphora, and dysgeusia, decreased tearing or epiphora, and facial hypesthesias/dysesthesias of V or IX .facial hypesthesias/dysesthesias of V or IX .Although the exact etiology of Bell's palsy is still Although the exact etiology of Bell's palsy is still unclear, most clinicians believe that herpes unclear, most clinicians believe that herpes simplex infection is the most likely agent. This simplex infection is the most likely agent. This belief is supported by an increased incidence of belief is supported by an increased incidence of HSV antibodies in patients with Bell's palsy HSV antibodies in patients with Bell's palsy when compared to age-matched controlswhen compared to age-matched controls

Bell’s PalsyBell’s Palsy

The treatment of Bell's palsy is variable, ranging from The treatment of Bell's palsy is variable, ranging from observation to surgical decompression. Regardless of observation to surgical decompression. Regardless of treatment given, all patients must be counselled treatment given, all patients must be counselled regarding proper eye care to prevent exposure keratitis. regarding proper eye care to prevent exposure keratitis. Patients should use natural tears liberally during the day Patients should use natural tears liberally during the day and should place lacrilube ointment in the eye at night. and should place lacrilube ointment in the eye at night. Taping of the eye lids during sleep may be helpful as Taping of the eye lids during sleep may be helpful as well as the use of a moisture chamber.well as the use of a moisture chamber.Patients should avoid fans and dust, and should consider Patients should avoid fans and dust, and should consider wearing eye protection when outside in the wind. wearing eye protection when outside in the wind.

Management of Bell’s PalsyManagement of Bell’s Palsy

ObservationObservation

Medical TreatmentMedical Treatment– SteroidSteroid– Anti-viral agentsAnti-viral agents

SurgerySurgery– DecompressionDecompression– Dynamic vs. static reanimationDynamic vs. static reanimation

Facial RehabilitationFacial Rehabilitation

TraumaTrauma

Trauma is the second most common cause of facial nerve paralysis. Trauma is the second most common cause of facial nerve paralysis. Longitudinal fractures of the temporal bone make up 80% of all Longitudinal fractures of the temporal bone make up 80% of all temporal bone fractures. temporal bone fractures. In this type, the fracture line extends along the longitudinal axis of In this type, the fracture line extends along the longitudinal axis of the temporal bone resulting in an external auditory canal laceration, the temporal bone resulting in an external auditory canal laceration, TM perforation, and possible ossicular disruption or TM perforation, and possible ossicular disruption or hemotympanum. Facial nerve injury occurs in 10 to 20% of these hemotympanum. Facial nerve injury occurs in 10 to 20% of these fractures with the injury most common in the perigeniculate region. fractures with the injury most common in the perigeniculate region. Transverse fractures are much less common (20% of all temporal Transverse fractures are much less common (20% of all temporal bone fractures). These fractures extend along the transverse axis of bone fractures). These fractures extend along the transverse axis of the temporal bone across the vestibule, resulting in sensorineural the temporal bone across the vestibule, resulting in sensorineural hearing loss, possible loss of vestibular function, and a 50% chance hearing loss, possible loss of vestibular function, and a 50% chance of facial nerve injury which is also usually in the perigeniculate of facial nerve injury which is also usually in the perigeniculate region. region.

T-bone FractureT-bone Fracture

For complete facial nerve paralysis with clinical evidence of a For complete facial nerve paralysis with clinical evidence of a temporal bone fracture, obtain a high resolution CT scan/temporal temporal bone fracture, obtain a high resolution CT scan/temporal bone protocol. bone protocol. If an obvious fracture is present, surgical exploration of the facial If an obvious fracture is present, surgical exploration of the facial nerve should be undertaken as soon as possible via either a nerve should be undertaken as soon as possible via either a transmastoid/translabyrinthine (+ SNHL) or transmastoid/middle transmastoid/translabyrinthine (+ SNHL) or transmastoid/middle fossa approach (- SNHL).fossa approach (- SNHL). During exploration the nerve must be fully exposed in order to During exploration the nerve must be fully exposed in order to identify all injured segments, and remove any compression from identify all injured segments, and remove any compression from fracture fragments. fracture fragments. The nerve sheath should be incised and any hematomas within the The nerve sheath should be incised and any hematomas within the sheath must be carefully evacuated.sheath must be carefully evacuated. If complete transection of the nerve is found during exploration, a If complete transection of the nerve is found during exploration, a direct end-to-end anastomosis should be performed if possible. direct end-to-end anastomosis should be performed if possible.

Longitudinal vs TransverseLongitudinal vs Transverse

T-Bone FractureT-Bone Fracture

For incomplete facial nerve paralysis or for For incomplete facial nerve paralysis or for delayed onset paralysis associated with a delayed onset paralysis associated with a temporal bone fracture, facial nerve testing temporal bone fracture, facial nerve testing should be obtained on day 4 after onset. should be obtained on day 4 after onset.

If advanced degeneration has occurred, If advanced degeneration has occurred, the nerve should be surgically explored the nerve should be surgically explored and decompressed. and decompressed.

Herpes Zoster OticusHerpes Zoster Oticus

Third most common cause of facial nerve paralysis. Third most common cause of facial nerve paralysis. This is a manifestation of a dormant varicella zoster virus This is a manifestation of a dormant varicella zoster virus reactivating in extramedullary cranial nerve ganglia reactivating in extramedullary cranial nerve ganglia during a period of decreased cell mediated immunity. during a period of decreased cell mediated immunity. The prodromal symptoms are very similar to those seen The prodromal symptoms are very similar to those seen in Bell's palsy, but are usually more severe. Symptoms in Bell's palsy, but are usually more severe. Symptoms include severe otalgia, facial paralysis, facial numbness, include severe otalgia, facial paralysis, facial numbness, and a vesicular eruption on the concha, external auditory and a vesicular eruption on the concha, external auditory canal, and palate. canal, and palate. Patients may also have varying degrees of SNHL, Patients may also have varying degrees of SNHL, vestibular symptoms, and associated cranial nerve vestibular symptoms, and associated cranial nerve symptoms. symptoms.

Herpes Zoster OticusHerpes Zoster Oticus

Laboratory evaluation will often show the rise and fall of Laboratory evaluation will often show the rise and fall of antibody titers specific for the virus. The palsy is usually antibody titers specific for the virus. The palsy is usually more severe and the prognosis much poorer compared more severe and the prognosis much poorer compared to Bell's palsy. to Bell's palsy. Only about 50% of these patients regain normal facial Only about 50% of these patients regain normal facial function as opposed to 90% with Bell's palsy. The function as opposed to 90% with Bell's palsy. The degeneration occurs more slowly, usually over three degeneration occurs more slowly, usually over three weeks instead of two. weeks instead of two. Treatment includes steroids, valacyclovir 1 gm po tid, Treatment includes steroids, valacyclovir 1 gm po tid, and proper eye care. Surgical decompression has not and proper eye care. Surgical decompression has not been proven beneficial but may be considered for ENoG been proven beneficial but may be considered for ENoG showing greater than 90% degeneration. showing greater than 90% degeneration.

Otitis MediaOtitis Media

In patients with evidence of acute otitis media, dehiscences in the In patients with evidence of acute otitis media, dehiscences in the fallopian canal may serve as portals for direct bacterial invasion and fallopian canal may serve as portals for direct bacterial invasion and inflammation along the nerve. inflammation along the nerve. Facial paralysis may begin within a few days of onset of an acute Facial paralysis may begin within a few days of onset of an acute otitis media and is usually incomplete. Treatment includes a wide otitis media and is usually incomplete. Treatment includes a wide myringotomy, drainage, and culture with antibiotic coverage for myringotomy, drainage, and culture with antibiotic coverage for gram positive cocci and H. flu. gram positive cocci and H. flu. The facial palsy associated with acute otitis media generally The facial palsy associated with acute otitis media generally resolves with aggressive management of the infection. resolves with aggressive management of the infection. However, if a total paralysis is present, serial ENoG should be However, if a total paralysis is present, serial ENoG should be obtained. If axonal degeneration reaches > 90%, surgical obtained. If axonal degeneration reaches > 90%, surgical exploration and decompression should be performed. exploration and decompression should be performed.

Acute Otitis MediaAcute Otitis Media

Chronic Otitis MediaChronic Otitis Media

Develop facial paralysis which is usually Develop facial paralysis which is usually secondary to cholesteatoma or from secondary to cholesteatoma or from inflammation/osteitis compressing the inflammation/osteitis compressing the facial nerve. facial nerve. In these cases a high resolution CT should In these cases a high resolution CT should be obtained, and surgery should be be obtained, and surgery should be performed as soon as possible performed as soon as possible (tympanomastoidectomy, facial nerve (tympanomastoidectomy, facial nerve exploration and decompression). exploration and decompression).

Chronic Otitis MediaChronic Otitis Media

TumorsTumors

About 5% of cases of facial nerve paralysis are About 5% of cases of facial nerve paralysis are caused by tumors. caused by tumors. Factors which should increase the clinicians Factors which should increase the clinicians suspicion of a possible tumor include: a slowly suspicion of a possible tumor include: a slowly developing paresis over more than three weeks, developing paresis over more than three weeks, facial twitching, additional cranial nerve deficits, facial twitching, additional cranial nerve deficits, recurrent ipsilateral involvement, associated recurrent ipsilateral involvement, associated adenopathy, or a palpable neck or parotid mass.adenopathy, or a palpable neck or parotid mass. In these cases, MRI and CT should be In these cases, MRI and CT should be obtained.obtained.

TumorsTumors

The most common benign tumor causing facial nerve The most common benign tumor causing facial nerve paralysis is a facial nerve schwanomma.paralysis is a facial nerve schwanomma. The most common malignant tumors causing facial The most common malignant tumors causing facial paralysis are mucoepidermoid carcinoma and adenoid paralysis are mucoepidermoid carcinoma and adenoid cystic carcinoma of the parotid gland. cystic carcinoma of the parotid gland. The management of facial nerve paralysis caused by The management of facial nerve paralysis caused by tumors depends upon the lesions location, size, and tumors depends upon the lesions location, size, and malignant potential and may include transposition of the malignant potential and may include transposition of the nerve, division and reanastomosis, interposition grafting, nerve, division and reanastomosis, interposition grafting, and cranial nerve crossover.and cranial nerve crossover. After nerve grafts, the best possible result that can be After nerve grafts, the best possible result that can be expected is a House grade III paresis. expected is a House grade III paresis.

TumorsTumors

Melkerson-Rosenthal SyndromeMelkerson-Rosenthal Syndrome

Rare disease that consists of a triad of symptoms: recurrent Rare disease that consists of a triad of symptoms: recurrent orofacial edema, recurrent facial palsy, and lingua plicata (fissured orofacial edema, recurrent facial palsy, and lingua plicata (fissured tongue). tongue). The defining feature of this disease is the persistent or recurrent The defining feature of this disease is the persistent or recurrent nonpitting facial edema that cannot be explained by infection, nonpitting facial edema that cannot be explained by infection, malignancy, or connective tissue disorder. malignancy, or connective tissue disorder. It usually involves the lips and buccal area and may involve the It usually involves the lips and buccal area and may involve the gingiva, palate, and tongue. gingiva, palate, and tongue. The lips become chapped, fissured, and red-brown in appearance The lips become chapped, fissured, and red-brown in appearance and may develop permanent deformity after numerous recurrences. and may develop permanent deformity after numerous recurrences. Facial paralysis and lingua plicata occur in half of the patients. The Facial paralysis and lingua plicata occur in half of the patients. The complete triad is only present in 25% of these patientscomplete triad is only present in 25% of these patients

Melkerson-Rosenthal SyndromeMelkerson-Rosenthal Syndrome

The complete triad is only present in 25% of these The complete triad is only present in 25% of these patients. This condition usually starts in the second patients. This condition usually starts in the second decade of life, and the manifestations usually occur decade of life, and the manifestations usually occur sequentially (rarely simultaneously). sequentially (rarely simultaneously). The etiology of this syndrome is unknown. Some The etiology of this syndrome is unknown. Some consider it a variant of sarcoidosis secondary to biopsies consider it a variant of sarcoidosis secondary to biopsies of the lips which may reveal noncaseating granulomas. of the lips which may reveal noncaseating granulomas. Facial paralysis occurs in 50 to 90% of these patients Facial paralysis occurs in 50 to 90% of these patients and tends to be abrupt. A history of bilateral sequential and tends to be abrupt. A history of bilateral sequential paralysis and relapse after initial recovery is common. paralysis and relapse after initial recovery is common. The site of the paralysis usually corresponds to the facial The site of the paralysis usually corresponds to the facial swelling. Facial nerve decompression may be indicated if swelling. Facial nerve decompression may be indicated if episodes of facial paralysis are frequent and episodes of facial paralysis are frequent and progressive. progressive.

Melkerson-Rosenthal SyndromeMelkerson-Rosenthal Syndrome

Newborn ParalysisNewborn Paralysis

Newborn facial paralysis is estimated to have an Newborn facial paralysis is estimated to have an incidence of about 0.23% of live births. incidence of about 0.23% of live births. The most common cause is birth trauma (80%), The most common cause is birth trauma (80%), which is usually evident by other signs of injury. which is usually evident by other signs of injury. These include a history of a difficult delivery with These include a history of a difficult delivery with or without forceps, facial swelling, bruising over or without forceps, facial swelling, bruising over the mastoid or extratemporal course of the the mastoid or extratemporal course of the nerve, and hemotympanum. nerve, and hemotympanum. The mechanism of injury is thought to be from The mechanism of injury is thought to be from direct pressure during forceps use or from direct pressure during forceps use or from pressure on the infants face by the sacral pressure on the infants face by the sacral prominence during delivery. prominence during delivery.

Congenital ParalysisCongenital Paralysis

Congenital causes of newborn facial paralysis are much less Congenital causes of newborn facial paralysis are much less common. common. Mobius' syndrome consists of a broad spectrum of clinical findings Mobius' syndrome consists of a broad spectrum of clinical findings which can range from an isolated unilateral facial paralysis to which can range from an isolated unilateral facial paralysis to bilateral absence of facial and abducens nerve functionbilateral absence of facial and abducens nerve functionIn this syndrome, the facial nerve forms but consists of only a In this syndrome, the facial nerve forms but consists of only a fibrotic tract. The muscles of facial expression may form in some fibrotic tract. The muscles of facial expression may form in some cases, but degeneration to fibrosis generally occurs rapidly. cases, but degeneration to fibrosis generally occurs rapidly. These children will have no response on EMG at birth and have no These children will have no response on EMG at birth and have no chance of spontaneous recovery of facial function. Many other chance of spontaneous recovery of facial function. Many other cranial nerves may be involved (III, IV, IX, X, XII) and skeletal cranial nerves may be involved (III, IV, IX, X, XII) and skeletal abnormalities may be present. abnormalities may be present. Treatment for these causes of newborn facial paralysis is generally Treatment for these causes of newborn facial paralysis is generally delayed until late childhood and usually requires static slings and delayed until late childhood and usually requires static slings and muscle transfers. muscle transfers.

Mobius SyndromeMobius Syndrome

Congenital ParalysisCongenital Paralysis

Newborns who present with a complete facial nerve Newborns who present with a complete facial nerve paralysis should undergo electrical testing within the first paralysis should undergo electrical testing within the first three days of life to differentiate between congenital and three days of life to differentiate between congenital and traumatic causes.traumatic causes. After birth trauma, the nerve can be stimulated for up to After birth trauma, the nerve can be stimulated for up to five days post injury and fibrillation potentials will be seen five days post injury and fibrillation potentials will be seen on EMG at ten to fourteen days. on EMG at ten to fourteen days. In congenital cases, the nerve will usually not stimulate In congenital cases, the nerve will usually not stimulate and no fibrillation potentials will be seen on EMG. and no fibrillation potentials will be seen on EMG. The prognosis for trauma related facial nerve paralysis at The prognosis for trauma related facial nerve paralysis at birth is usually excellent. birth is usually excellent. Surgical decompression should not be considered until Surgical decompression should not be considered until the nerve has had a chance to recover or until >90% the nerve has had a chance to recover or until >90% degeneration has occurred. degeneration has occurred.

SarcoidosisSarcoidosis

Chronic noncaseating granulomatous disease usually characterized Chronic noncaseating granulomatous disease usually characterized by hilar or peripheral adenopathy, polyarthralgias, anergy, elevated by hilar or peripheral adenopathy, polyarthralgias, anergy, elevated serum calcium, and hepatic dysfunction. serum calcium, and hepatic dysfunction. One variant of sarcoidosis, Heerfordt's disease (a.k.a. uveoparotid One variant of sarcoidosis, Heerfordt's disease (a.k.a. uveoparotid fever) consists of uveitis, mild fever, nonsuppurative parotitis, and fever) consists of uveitis, mild fever, nonsuppurative parotitis, and cranial nerve paralysis. cranial nerve paralysis. The facial nerve is the most commonly involved cranial nerve and The facial nerve is the most commonly involved cranial nerve and the paralysis usually starts abruptly days to months after the the paralysis usually starts abruptly days to months after the parotitis.parotitis. In these cases, the paralysis is considered to be from direct In these cases, the paralysis is considered to be from direct invasion of the nerve by the granulomatous process. invasion of the nerve by the granulomatous process. An elevated serum angiotensin-converting enzyme (ACE) generally An elevated serum angiotensin-converting enzyme (ACE) generally confirms the diagnosis, and treatment consists of steroids. confirms the diagnosis, and treatment consists of steroids.

Heerfordt's diseaseHeerfordt's disease

Lyme DiseaseLyme Disease

Tick-borne spirochete Borrelia burgdorferi. Several species of Tick-borne spirochete Borrelia burgdorferi. Several species of Ixodes ticks carry the spirochete, and the primary reservoir is the Ixodes ticks carry the spirochete, and the primary reservoir is the white-tailed deer and white-footed mouse. white-tailed deer and white-footed mouse. The disease generally occurs in several stages. The first stage The disease generally occurs in several stages. The first stage consists of a flu-like illness with regional lymphadenopathy, general consists of a flu-like illness with regional lymphadenopathy, general malaise, and erythema migrans (erythematous enlarging annular malaise, and erythema migrans (erythematous enlarging annular skin lesions found anywhere on the body). The second stage skin lesions found anywhere on the body). The second stage usually starts several weeks to months later with neurologic usually starts several weeks to months later with neurologic abnormalities. These include meningitis and cranial and peripheral abnormalities. These include meningitis and cranial and peripheral nerve neuropathies. The final stage occurs months to years later in nerve neuropathies. The final stage occurs months to years later in the form of recurrent meningitis, subtle mental disorders or the form of recurrent meningitis, subtle mental disorders or neurologic deficits, and chronic arthritis. neurologic deficits, and chronic arthritis. Ten percent of these patients develop facial paralysis (unilateral or Ten percent of these patients develop facial paralysis (unilateral or bilateral) and hearing loss. The facial paralysis typically resolves bilateral) and hearing loss. The facial paralysis typically resolves completely, but may rarely result in mild permanent facial weakness. completely, but may rarely result in mild permanent facial weakness. Treatment for Lyme disease consists of IV ceftriaxone (2 g/day) or Treatment for Lyme disease consists of IV ceftriaxone (2 g/day) or doxycycline for fourteen days. doxycycline for fourteen days.

Lyme DiseaseLyme Disease

ConclusionConclusion

Although Bell's palsy remains the most common cause of acute Although Bell's palsy remains the most common cause of acute facial nerve paralysis, it is important for clinicians to consider all facial nerve paralysis, it is important for clinicians to consider all causes to avoid overlooking potentially life-threatening diseases. causes to avoid overlooking potentially life-threatening diseases. A good history and physical is mandatory in the work-up of these A good history and physical is mandatory in the work-up of these patients and will usually help to significantly narrow the possible patients and will usually help to significantly narrow the possible causes.causes. Although topognostic testing is of historical interest, it has not Although topognostic testing is of historical interest, it has not proven to be of much use clinically. proven to be of much use clinically. ENoG is the most useful electrophysiologic test and should be ENoG is the most useful electrophysiologic test and should be performed within 4 - 6 days post-onset in patients with a complete performed within 4 - 6 days post-onset in patients with a complete paralysis with surgical decompression considered for > 90% paralysis with surgical decompression considered for > 90% degeneration. degeneration. Treatment plans should be individualized in each patient, but must Treatment plans should be individualized in each patient, but must include education on eye protection include education on eye protection