Postoperative Facial Paralysis

Naumann Book (Editor Dr Hans Heinz) = Head and Neck Surgery Vol 3 , page 209 This is the BIG textbook series from Munich in Germany.

page. 209

Any postoperative facial paralysis, that is not obviously referable to temporary swelling, and is not promptly improved by measures to reduce swelling, should be surgically explored to advance the diagnosis, and avoid medicolegal consequences.

If necessary, the original surgeon should not hesitate to refer the patient to a surgeon considered to be more competent.

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Prof Jongkees - Amsterdam

became very widely quoted in the world for saying::

"In the event of a postoperative facial palsy, the sun should not set before the nerve is re-explored - or at least done the next day, assisted by a senior and experienced colleague".

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Mark May (Pittsburgh, USA:

The re-exploration should be done within 3 days.

Also:

BooK: The Facial Nerve (877 pages - Thieme publishers 2000

pages 380-381:

Management of Unintentional Iatrogenic Facial Paralysis

Two types of iatrogenic injuries may occur: one that is an expected complication of a procedure and is recognized at the time of surgery, and the other that is recognized postoperatively and is unexpected.

Recognized at Surgery:

When the surgeon recognizes that the nerve has been transected, it should be repaired during the primary surgery. After the patient and family have been told of the circumstances of the injury and the measures taken to correct it, they should be informed of the time and quality of recovery expected.. No return of function should be anticipated sooner than 4 months after transection of the nerve, and at least some recovery should begin by 8 months following acute injury and repair and continue for up to 2 years after surgery. If no recovery is noted by the 8th month, the surgeon should consider re-exploring the nerve to examine the site of repair, because repairs performed a year or longer after injury rarely result in serviceable function ( see Chapter 3 and 33, and Chapter 39, Case 2).

Recognized Postoperatively:

Any time surgery is performed in the region of the facial nerve, the patient should be evaluated in the immediate postoperative period to determine the integrity of facial nerve function. This evaluation can begin in the recovery room, even before the patients is fully responsive. The presence of nasal alar flaring on the operated side is a welcome sign that the facial nerve has not been transected and can be elicited by pinching the nares for a few seconds and then releasing them. Because the presence of nasal flaring does not rule out partial injury to the upper or lower divisions of the nerve, facial nerve integrity may also be evaluated by pressing on the supraorbital area or pinching the skin over the supraclavicular area. These will cause even an unconscious patient to grimace in pain, and the two sides of the face may be evaluated for equal response to the stimulus.

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In contrast to the utility and reliability of these two signs, the ability of the awake patient to close or approximate the eyelids is of a very limited value in evaluating facial function.

Postoperative edema, limitation of mobility due to a mastoid or head dressing, the effects of gravity with the patient supine, the quality of the patient's skin, and the fact that eye closure may be intact for up to 10 days after the injury to the facial nerve, all make eye closure an inaccurate indication of facial nerve function ( see Chapter 37).

Once it is apparent that facial paralysis is present, its probable duration must be determined. It has been said that the "sun should not set on an immediate postoperative facial paralysis." The implication of this statement is accurate, but exceptions do exist. If local anesthesia was used during the procedure, sufficient time must elapse to ensure that its effects have dissipated. In such cases, facial function will recover within 2 to 12 hours, depending on the duration of action of the anesthetic, and the patient and family be reassured that the paralysis will resolve.

If recovery does not occur within the next 24 hours, the surgeon may elect to evaluate the facial nerve by electrical testing as described previously ( See Chapter 12). If the response to EEMG (evoked electromyography) drops to 10% or less of normal within the first 5 days postinjury and the surgeon did not see the facial nerve at surgery, re-exploration should be considered. When re-exploration is indicated , it should be performed by the primary surgeon, but if this is not feasible, then the most experienced surgeon available should be consulted. How the situation is presented to the patient can have a great effect on the patient's acceptance of the paralysis and willingness to work with the medical team to find solutions to the problem. If the patient agrees to re-exploration, it should be performed as soon as possible following the injury to minimize the formation of granulation tissue, inflammation, and scar tissue that tends to obscure the surgical field. Details regarding nerve repair are described in Chapter 33.

Delayed or Incomplete Palsy

Facial paresis has been noted to occur as long as 14 days after a procedure performed in the region of the facial nerve. The role of viral reactivation after acoustic schwannoma resection has been documented by Gianoli and Kartush. In the majority of these cases, involvement is incomplete, the patient begins to recover within 3 weeks, and as long as the weakness does not progress to total paralysis, the natural history is the same as for a patient with delayed incomplete palsy. In the event that the weakness does progress to full paralysis, the severity of injury can be estimated by serial electrical testing as described in Chapter 12. However, it is unusual for patients with palsy of delayed onset to have less than satisfactory recovery, even when it progresses to complete palsy. Even when the response to EEMG (evoked

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electromyography) is lost within 14 days after onset of the palsy, recovery usually begins within 2 to 4 months. Recovery may be unsatisfactory in such patients due to faulty regeneration, but there id no evidence that exploring these patients favourably influences that recovery.

Pseudopalsies and Old Deficits

Partial or regional facial deficits may be noted by the patient, family or surgeon in the immediate postoperative period. Although they may not be related to injury to the facial nerve, they may still cause great concern. Facial edema associated with the trauma of surgery may limit facial movement, but the facial stiffness will subside as the edema subsides. A potentially more serious cause of concern is the postoperative persistence of a deficit unnoticed by the surgeon during preoperative evaluation. In order to avoid misunderstanding in these cases, the surgeon should perform thorough preoperative evaluation, documenting any facial nerve deficit by notation, photograph, and video, and share this information with the patient and family before any surgical procedure is undertaken.

Summary

The facial nerve may be injured during surgery in the cerebellopontine angle, temporal bone, face or neck. Even the most experienced surgeon may unintentionally injure the facial nerve, particularly when surgical planes are distorted or obscured by inflammation, trauma or tumor. The course of the facial nerve may be aberrant due to congenital abnormalities unanticipated by the surgeon. A thorough knowledge of facial nerve anatomy and meticulous attention to surgical technique can reduce the risk of injury, but every surgeon must be prepared to manage such iatrogenic facial nerve injuries. Treatment varies according to the type injury, (transection, compression, or stretching), or where the injury occurred (intracranial, temporal bone, erxtracranial), whether the palsy was delayed or sudden, and whether facial paralysis was complete or incomplete. Electrical testing may help to choose the appropriate course of action, which may be re-exploration and nerve repair, watchful waiting, or facial reanimation at a later date.

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UTMB = University Texas Medical BranchDr Francis Quinn, Dr Jeffrey Vrabec

+Discussant: Dr Kedar Adour, Sir Charles Bell Society, San Francisco

March 13, 1996

Injury during ear surgery:

If transection of the nerve occurs during surgery the nerve must be repaired.

If paralysis occurs postoperatively and the surgeon is confident that the nerve was intact at the conclusion of the case, a high resolution CT scan should be obtained and facial nerve testing should be done on postoperative day 4 - 6.If advanced degeneration is evident, surgical exploration and decompression should be done. If there is any question as to the integrity of the nerve, exploration should be done as soon as possible by a surgeon familiar with the intratemporal anatomy of the nerve and reconstruction techniques.

Electrophysiologic Tests:

These tests are useful for patients with complete paralysis for determining prognosis for return of facial function and the endpoint of degeneration by serial testing. The nerve excitability test (NET), maximal stimulation test (MST), and electroneuronography (ENoG) are most useful in the degeneration phase. These tests will give normal results during the first 72 hours after injury due to the stimulating and recording electrodes both being distal to the site of the injury

(HH: if the injury is proximal to the geniculate ganglion, e.g. in the internal auditory canal, it can be 1-2 days longer before the degeneration reaches distal to the stylomastoid foramen).

After 3-4 days, the nerve degeneration reaches the site of stimulation and useful results will be obtained. These tests can only be useful for unilateral paralysis because all three involve comparison to the contralateral side which must be normal for valid results.

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The well known Hilger stimulator uses metal tips for stimulating over the face, and this can be

Painful. When fitted with filt tips the stimulation is much less painful

The nerve excitability test (NET) is the most commonly used secondary to the low coat, readily available equipment, and ease of performance. The test involves placement of a stimulating electrode over the stylomastoid foramen. The lowest current necessary to produce a twitch on the paralyzed side of the face (threshold) is compared with the contralateral side. A difference greater than 3.5 milliamps indicates a poor prognosis for return of facial function. The major draw back to the use of this test is objectivity, with reliance on a visual point.

(HH: If the masseter chewing muscle is stimulated, an inexperienced observer may interpret that as a twitch of the facial muscles. Also, as happened in a case in dispute, the junior physiotherapist - who testified in court - stated that she could "feel" the movement of the face - the advocate would not allow me to convince him to stress the point that it is the visual observation which is the test!)--

In addition, such a small amount of current is used with this test, a few intact axons may give a visual response leading the clinician to predict a good prognosis, when in reality most of the fibers are degeneration.

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

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Electroneuronography (ENoG) is considered to be the best prognostic test because it provides an objective qualitative measurement of neual degeneration. The facial nerve is stimulated with an impulse transcutaneously at the stylomastoid foramen using bipolar electrodes. The muscular response is then recorded using bipolar electrodes placed in the nasolabial groove. The peak to peak amplitude of the evoked compound action potential is considered proportional to the number of intact axons. The two sides are then compared with the response on the paralyzed side o the face expressed as a percentage of the 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 poor prognosis for spontaneous recovery. A maximal reduction of less than 90% within 3 weeks of onset gives an expected spontaneous rate of recovery of 80 - 100%. Disadvantages of ENoG include discomfort (HH: No! if properly done), cost, and test-retest variability which is due to positioning of the electrodes and excitation of the muscles of mastication (V-nerve=trigeminal).

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Maximal Stimulation Test and Electroneurography (EnoG)

MST: Stimulation at the areas shown ENOG: Maximal stimulation at the stylomastoid above and the movements are observed.. foramen and the compound action potentials measured on the cheek or in the nasolabial fold.

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ENOG as developed by Esslen. Filter tipped electrodes are used forstimulation as well as for recording in the nasolabial fold.

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Electromyography (EMG) is of limited value early in the evaluation of facial paralysis because fibrillation potentials indicating axonal degeneration do not appear until 10 to 14 days post onset.

However, EMG becomes important for assessing reinnervation potential of the muscle two weeks after onset. By using needle electrodes placed transcutaneously into the muscles of facial expression, muscle action potentials generated by voluntary activity can be recorded. Electrical silence can indicate normal muscle in a resting state, severe muscle wasting and fibrosis or acute facial paralysis in the early stages. During normal voluntary contraction organized diphasic or triphasic potentials are seen. Fibrillation potentials indicate degeneration of the neural supply to the muscle in question. Polyphasic potentials indicate reinnervation. These are important because they usually appear 6 - 12 weeks before clinical return of function.

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Electrodiagnosis of Bell’s Palsy andOther Facial palsies

by

Herman HamersmaM.B., Ch.B. (Pretoria), M.D. (Amsterdam)

Otology and NeurotologyFlora Clinic, Roodepoort.

- - - - - - -

Herman HamersmaM.B., Ch.B. (Pretoria), M.D. (Amsterdam)

Otology and Neuro-otologyFlorida

Roodepoort

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Peripheral Facial Nerve Paralysis1200 Cases in 30 years’ practice

Presented at the annual ENT Congress in Bloemfontein in 2005

Hamersma Peitersen Devriese Croxon Florida Copenhagen Amsterdam) Sydney 25 yrs 25yrs 43 yrs 16 yrs

Bell 863 (72%) 1701 (66%) 50% 46%

Zoster 63 (5%} 116 (5%) 6% 12% Trauma 174 (15%) 95 (4%) 17% 30% Miscell 101 (8%) 570 (25%) 27% 12%

Recurrences 12% 7% 8% 1%

__________ _____________ ________ __________

Total = 1201 Peitersen 2570 8697 1000

Recurrent palsies:

Recurrences on the same side, new paralyses and recurrences on the contralateral side (also called alternating paralyses) are grouped together as “recurrent”. Kedar Adour (USA) reported recurrences in 9 % of Bells’ palsies.

Partial and Total Paralysis in Bell’s Palsy :

According to Peitersen, 30% of Bell’s palsies present as a partial paralysis (paresis) which do not progress to a total paralysis. 70% Present as a total paraysis, some of them starting as a partial paralysis and then progressing to a total paralysis after a few days, usually within 4 days.

Surgical decompressions for Bell’s palsy done by H.H.:

Surgical decompressions of the labyrinthine portion of the nerve and the geniculate ganglion via the middle fossa approach were performed in 65 cases in 30 years (2 per year). The surgery was done when total degeneration was threatening, or when it had occurred only a few days before. The latest operaton was done by day 14, because

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even then the recovery of facial movement resulted in less synkinesia and contractures than occurred when these type of patients were not operated at all.

Presented at the Annual Congress of the South African Society of Otolaryngology, Head and Neck Surgery in Bloemfontein, November 2005.

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Marble Bone Disease:

55 Cases of sclerosing bone dysplasias (sclerosteosis and osteopetrosis – nickname = marble bone disease) can be added to the 101 miscellaneous cases of the Florida list, but they are excluded in order to make comparison with international data possible. In these rare conditions, the facial palsies present as acute, recurrent palsies, similar to Bell’s palsy, in early childhood already but the nerve always degenerates totally and recovers partially after 3 – 5 months. Total facial nerve decompressions (in two stages) were performed in 26 children from ages 2 – 12 (many done on both sides).

For the forehead the observer should use four fingers on the forehead and the thumb on the nasion (the root of the nose). The same method is used to observe movements to close the eye. For the mouthone or two fingers press on the upper lip against the teeth, and two fingers immobilize the lower lip.

On trying to close the eye, one will observe that the eyeball tilts upwards (Bell’s phenomenon). This tilting of the eyeball must be kept in mind when examining for a return of function of the muscles which close the eye – one should then immobilize the lower eyelid with one finger and ask the patient to close the eye. If there is any real movement of the

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muscles below the eye, one will feel the muscles moving (advice of Dr Devriese, Amsterdam)..

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Example of elctrodiagnosis with VenoG

Observe the voluntary movements of the frontalis, orbicularis oculi, and orbicularis oris, and give it a percentage score (normal if never paralised before, otherwise less if patient had a previous paralysis).

1. Do a Schirmer test. Although the topographical value is disputed, a dry eye and a bilateral shutdown are very important findings.

Schirmer test

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2. Electrodiagnosis: Start with the normal side, and stimulate at the stylomastoid foramen using felt tipped probes.

The above picture illustrates stimulation at the stylomastoid foramen and observing the muscle contractions.

Start with a small stimulation, and then increase to the maximum the patient can tolerate. Do not mistake a contraction of the masseter for a facial nerve response.If the masseter jerks, move the stimulating electrodes more posteriorly in order to reduce stimulation of the trigeminal nerve. .

Observation of the facial nerve response:

Establish a base line on Day 1 – 3 – (it will always be normal).

Forehead (frontal branch) – give it a percentage score (compare with the normal side which is 100%).

Eye (zygomatic branch) - dito.

Mouth (buccal branch) - ditto.

Next tests:

Day 4

Day 5

Day 6

Day 7

Day 8

Day 10

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Day 12

Day 14

After Day 18 the electrical tests become less accurate.

ENOG:

The author has found that the calculation of the percentage degeneration (in comparison with the normal side) varies too much, and recommends that the absolute values be recorded and taken as important. Thus

Respoinses above 1.0 millivolt – nothing to worry about.

“ betewen 0,5 – 1.0 mV – do daily tests.

“ at 0,5 mv – red Flag!

“ below 0,5 mv - bells ringing!

Example of clinical notes in case of a left sided paralysis:

Day 1: Voluntary movement : Forehead 50%, Eye 50%, Mouth 50% (as compared with right side). No electrical tests because they will be normal.

Day 3: Voluntary movement: FH= 0, Eye = 0, Mouth =0%Schirmer: L= 2 cm, Right 5 cmVenoG: L = 80% all branches (compared with right side)

Day 5: Voluntary movement – total paralysis leftSchirmer: Left 0,5 cmVenoG: L = 50% all branches

Day 6: Vol movement: 0%Schirmer: Dry eyeVenoG: L = 20% all branches. EnoG advised.

Day 7: Vol movement: 0%Schirmer: Dry eyeVenog: L = 5%EnoG: Left 0,5 mv, R = 5,0 MV

Advise that decompression may become necessry.

Day 8: Vol: 0%, dry eye.VenoG: L = 5%EnoG: Left 0,4 mV

Day 10: Vol 0%, dry eye.VenoG: L 5%

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EnoG = o,4 mv

Day 12: Vol 0%, eye starts tearingVenoG: 5%EnoG: 0,4 mv

Day 16: Vol: 5% movement foreheadVenoG: 5%

Day 20: Voluntary movement FH 50%, eye 20%, mouth 20%.Voila! Both patient and doctor happy because the monitoring of the

processwas done in a scientific way with little guesswork. This is the 21st century!

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Controversies In Otolaryngology - Editor: Myles Pensak - Thieme Publishers

Acute Facial Paralysis by

Douglas A Owen & Moises Ariaga

Page 227 - 230: Chapter 42

Excerpts

The most common causes of acute unilateral facial paralysis include Bell's palsy and trauma to the temporal bone.

The physical as well as emotional liability it produces can be devastating.

Accurate evaluation and proper management can reduce the sequelae the patient may sustain.

Because most facial palsies are associated with some spontaneous resolution, the evaluation of various treatment modalities has been problematic.

Important prognostic management implications can be determined by means of accurate observation at the time of initial physical examination, with documentation of the degree of facial function that subsequently deteriorates.

The House-Brackman classification grading of facial paralysis has been widely accepted and it is recommended by the American Academy of Otolaryngology - Head and Neck Surgery (AAO - HNS)

Electrodiagnostic Testing

Electrodiagnosting testing has been advocated as an important element in diagnostic evaluation of facial paralysis.

It is used to determine the extent of facial nerve injury and to provided prognostic information for the use treatment planning.

The electriucal tests that we have found the most helpful include electroneuronography (ENoG), volitional motor unit potentials on electromyography (EMG), spontaneous EMG responses, and Hilger nerve stimulation minimal nerve excitability test (NET).

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ENoG is used to document the extent of facial nerve degeneration in comparison with the contralateral side. It should not be performed until approximately 3-4 days after the development of a complete unilateral paralysis.

ENoG provides vakuable information up to 21 days after injury.

Degeneration to less than 10% function compared with the contralateral side, is considered significant, and is considered to be the threshold for possible surgical exploration.

NET test introduces subjectivity in that it relies on visual detection of response.

EMG responses reflect postsynaptic membrane potentials that may be either initiated at the neuromuscular junction voluntarily or spontaneously across the membrane potential.

The presence of voluntary EMG facial motoring unit potentials early on after an acute facial paralysis was noted by Granger to be associated with ultimate recovery from a facial paralysis.

Motor unit potentials in four or five muscle groups during the first 3 days after onset of an acute facial paralysis was associated with satisfacrry outcomes in moe than 90% of the patients

Thus, the presence of EMG voluntary facial muscle potentials despite clinically absent motion has important prognostic implications.

Spontaneous EMG activity has prognostic implications at 6 months after a major intratemporal facial nerve injury.

Fibrillation potentials in the muscle are considered evidence of continuing complete denervation.

Polyphasic potentials are considered evidence of regeneration, as well as a good prognostic finding.

Reevaluation with EMG at the 6-momth point has been selected beause this provides adequate time for an intratemporal facial nerve injury to regenerate at the expected 1-mm/day growth rate to the facial periphery.

Iatrogenic Trauma

The patient who has iatrogenic facial paralysis, is usually noted to have the paralysis in the recovery room immediately after surgery.

The temporal (time) relationship between the surgery and the onset of paralysis obviously suggests that the surgical procedure is the cause of the paralysis.

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The first step in the management of these patients is to consider each step of the procedure, and the possible involvement of the facial nerve.

Reasonable time should be given for the effect of local anaesthesia to dissipate.

In addition, if the ear or mastoid cavity was packed with firm material, this should be loosened to provide an opportunity for any direct pressure on the nerve to dissipate as well..After a few hours, to allow these maneuvers to take effect, if the paralysis persists, consideration should be given for exploration of the facial nerve.

Volitional EMG potentials may be helpful at this time. Evidence of volitional motor unit potentials corroborates an intact nerve that will recover with time.

Immediate postoperative paralysis is an emotionally charged situation for the patient as well as the surgeon.

The surgeon should readily seek consultation in this situation, and should preferably perform the facial nerve exploration in conjunction with another surgeon who has particular expertise in facial nerve surgery. This produces the additional objectivity of another observer, as well as a surgeon who is less emotionally involved in the decision making process.

Th presence of another surgeon acting as a co-observer to record findings and decision making in a more objective fashion also has potential medicolegal ramifications In addition, although prompt exploration is indicated, waiting until the next morning for a complete fresh surgical team is preferable to subjecting thpatient to a same-day operation with a tean that is either tired or incomplete.

If an injury to the sheath is identified with herniation of nerve fibers through the damaged sheath, a segment of the nerve on either side of the injurt is decompressed, and the sheath is opened to prevent strangulation of the nerve.

Conclusion:

The case of an anatomically intact facial nerve, but with evidence of electrical degeneration, presents a therapeutic dilemma, regardless of whether trauma or Bell's palsy is the cause.

Some degree of spontaneous recovery without any therapy whould be expected in this setting, and so arises the controversy in treatment.

Although treatment with steroids or antiviral agents, or both, depending on etiology, may improve outcomes, in high-risk patients, the literature is still incomplete.

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In our opinion, the possible benefits of treatment despite potential side-effects, are worth the risk.

Until further research is complete, however, we remain cautious in our recommendations of the possible benefits of facial nerve decompression.

Anatomical disruption of the facial nerve is an absolute indication for exploration and possible grafting.

Determining the extent of injury preoperatively with CT scans and electrical testing can be difficult.

Even under direct inspection during surgery, an accurate determination can be difficult because of disease, a traumatic anatomical distortion, and surgeon bias.

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