The Acute Facial Palsies

Esslen, E

doi:10.1007/978-3-642-66534-9

Cited by 95 publications

(33 citation statements)

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“…The highest CMAP amplitude was obtained at the NFM muscles, in agreement with the observations of Esslen 6 and Thomander and Stalberg 23 , and is probably due to the high amount of muscle fibers innervated by the facial nerve in this region. The thickest branches of the facial nerves (zigomatic and the buccal branches) innervate the paranasal muscles which generate the CMAP recorded over this region.…”

Section: Discussionsupporting

confidence: 90%

Facial nerve electroneurography: variability in normal subjects

Medeiros

Nóbrega

Andrade

et al. 1996

Arq. Neuro-Psiquiatr.

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SUMMARY -Twenty normal individuals were submitted to facial nerve electroneurography using different techniques in order to determine the most accurate to obtain the latencies and amplitudes of the compound muscle action potentials (CMAP) of the facial muscles. First of all it was determined in which muscle or muscle group highest amplitude CMAP could be recorded with the lowest variability between sides and in test-retest. Different techniques were studied in order to determine which could give the best results. This was shown to be an arrangement of bipolar surface electrodes fixed to a plastic bar. The records with higher amplitude where obtained from the nasolabial fold muscles. Therefore 65 normal volunteers were examined using this technique and recording the potentials obtained over the nasolabial fold muscles. Normal values were determined (latency lower than 4.5 ms and amplitude larger than 2 mV -95% confidence limits).KEY WORDS: facial nerve, eletroneurography. Eletroneurografia do nervo facial: variabilidade em indivíduos normaisRESUMO -Vinte voluntários normais foram submetidos a eletroneurografia do nervo facial utilizando-se diferentes técnicas para a determinação da mais acurada para a obtenção das latências e amplitudes do potencial de ação muscular composto (CMAP) dos músculos faciais. Inicialmente determinou-se em qual músculo ou grupo muscular registra-se CMAP com maior amplitude e menor variabilidade entre lados e entre testes, assim como determinou-se qual técnica proporcionou melhores resultados. A que mostrou melhores resultados foi realizada com eletrodos de superfície bipolares de discos fixos em barra de plástico e os melhores registros foram obtidos nos músculos do sulco nasolabial. A seguir 65 voluntários normais foram estudados com esta técnica registrando-se os potenciais nos músculos do sulco nasolabial e foram determinados os valores normais para a latência (menor que 4,5 ms) e amplitude (acima de 2 mV). PALAVRAS-CHAVE: nervo facial, eletroneurografia.Since Desmedt's 4 description of compound muscle action potential (CMAP) in facial muscles, many electrophysiological techniques have been described aiming to establish an early prognosis for facial nerve palsy. Most of these techniques are based on comparative analysis between the CMAP obtained by the stimulation of the normal and damaged facial nerves. Another method is to compare the amplitude of the CMAP obtained by the stimulation of the damaged facial nerve with values obtained from a normal group of subjects, which is particulary helpful in patients with bilateral facial palsy. Fisch* and Esslen 7 considered that the percentage of reduction of the CMAP obtained on the paralyzed side is proportional to the number of affected nerve fibers. Many techniques have been described analyzing CMAPs of different facial muscles obtained with different stimuli and recording conditions 10,12 " 1416 "' 20 . To validate these techniques it must be assumed that normal subjects have small variability in CMAP amplitude between sides and in succ...

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Section: Discussionsupporting

confidence: 90%

Facial nerve electroneurography: variability in normal subjects

Medeiros

Nóbrega

Andrade

et al. 1996

Arq. Neuro-Psiquiatr.

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“…According to Zander Olsen 21 , the CMAP amplitude difference between the normal and paralyzed sides correlates with the number of surviving motor units. Esslen 5 and Fisch 7 stated that this difference corresponds to the amount of degenerate fibers on the affected side. We must be careful to establish a linear correlation between differences of amplitudes and the proportion of degenerate fibers like Esslen 5 and Fisch 7 do because the factors that determine the CMAP amplitude are complex and difficult to be controlled by the examiner (ex.…”

Section: Discussionmentioning

confidence: 99%

“…Esslen 5 and Fisch 7 stated that this difference corresponds to the amount of degenerate fibers on the affected side. We must be careful to establish a linear correlation between differences of amplitudes and the proportion of degenerate fibers like Esslen 5 and Fisch 7 do because the factors that determine the CMAP amplitude are complex and difficult to be controlled by the examiner (ex. in cases were the CMAP amplitude is very reduced the masseter muscle potential may impair the registration of the facial muscle potential).…”

Section: Discussionmentioning

confidence: 99%

Facial electroneurography in Bell's palsy: variability in the early stage and comparison between interpretation methods

Medeiros

Nóbrega

Andrade

et al. 1996

Arq. Neuro-Psiquiatr.

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-To determine the variability of the abnormalities found in the electroneurography (ENG) of the facial nerve in cases of Bell's palsy during the initial two week period was one of the objectives of the authors. A second one was to investigate the value of ENG as a tool to determine an early prognosis of recovery utilizing two different methods. In the first one the amplitude of the compound muscular action potential (CMAP) obtained on the paralyzed side was compared to this potential on the opposite (normal) side. The second method compared the CMAP on the paralyzed side to normal standardized data from normal individuals. A group of 33 patients with Bell's palsy was followed until total recovery or for at least 4 months, if the recovery was not achieved earlier. It was observed that amplitude of the CMAP become stable towards the sixth day of palsy and this is a good time to establish the prognosis. Another conclusion is that both methods were equivalent to determine the prognosis in Bell's palsy.KEY WORDS: electroneurography, Bell's palsy, facial nerve.Eletroneurografia do nervo facial na paralisia de Bell: variabilidade na fase aguda e comparação entre técnicas RESUMO -O objetivo deste trabalho é determinar a variabilidade da eletroneurografia (ENG) do nervo facial na paralisia de Bell durante as primeiras duas semanas e investigar o valor da ENG na determinação de um prognóstico precoce utilizando-se dois métodos diferentes. O primeiro método compara a amplitude do potencial de ação muscular composto obtido no lado paralisado com o lado normal e o segundo método compara o potencial de ação muscular composto obtido no lado paralisado com valores normativos. Um grupo de 33 pacientes com paralisia de Bell foi seguido até a recuperação total ou pelo menos por quatro meses nos casos em que não houve recuperação. Observou-se que a amplitude do potencial de ação muscular composto estabiliza-¬ se em torno do sexto dia e que este é um bom momento para se realizar o exame e se estabelecer um prognóstico. Outra conclusão é que ambos os métodos são equivalentes para determinação prognóstica. PALAVRAS-CHAVE: eletroneurografia, paralisia de Bell, nervo facial.The pathologic process in idiopathic peripheral facial palsy stabilizes two weeks after the beginning of the illness 58 . The usual method of electroneurography (ENG) used to determine the prognosis in Bell's palsy consists of comparing the amplitude of the compound muscular action potential (CMAP) registered on the affected side with the CMAP amplitude obtained on the normal hemiface. A large difference implies a great number of nerve fibers affected and a worse prognosis.

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“…[9,19] Considerable investigation into neurotmesis and its avoidance has been accomplished in idiopathic facial palsy, herpes zoster oticus, and traumatic facial palsy. [6] In anatomical studies of temporal bones Dobozi[5] has demonstrated that the fallopian canal is narrowest in relation to facial nerve diameter in its labyrinthine segment. Gantz, et al.,[7] have shown with intraoperative evoked electromyography (EMG) in idiopathic palsies that the block to axonal impulse conductivity is found in the labyrinthine segment.…”

mentioning

confidence: 99%

“…Another theoretical mechanism is compression of the facial nerve in the labyrinthine segment of the temporal bone. [1,6] Consequently, some authors have advocated meatal decompression of the facial nerve during translabyrinthine acoustic neuroma approaches. [9,19] Considerable investigation into neurotmesis and its avoidance has been accomplished in idiopathic facial palsy, herpes zoster oticus, and traumatic facial palsy.…”

mentioning

confidence: 99%

Decompression of the labyrinthine segment of the facial nerve in acoustic neuroma surgery: a consideration for minimizing postoperative delayed facial nerve dysfunction

Holliday¹,

Sampath²

1998

FOC

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Delayed facial nerve palsy, a condition characterized by spontaneous deterioration of facial nerve function in patients who had otherwise normal or near-normal facial function in the immediate postoperative period, has been reported in 15 to 29% of patients undergoing microsurgical resection of vestibular schwannomas. One putative mechanism for its occurrence suggests that edematous entrapment of the facial nerve in the meatal foramen (the narrowest segment of the internal auditory canal) may lead to nerve ischemia or necrosis and subsequent facial nerve dysfunction. To assess whether meatal decompression may help reduce the incidence of delayed facial nerve palsy during microsurgical resection of acoustic tumors, we compared 25 patients undergoing translabyrinthine removal of acoustic neuromas who received prophylactic decompression of the labyrinthine segment of the facial nerve (Group 1) with 40 patients who did not receive facial nerve decompression (Group 2). No patients in Group 1 had a delayed progressive facial paralysis with degeneration. In contrast, when Group 2 patients with larger, average-sized tumors were reviewed, eight patients (20%) developed delayed degeneration. These findings suggest that decompression of the labyrinthine segment may be of value in acoustic tumor surgery in reducing delayed facial nerve dysfunction. Further study is indicated in this important area.

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The Acute Facial Palsies

Cited by 95 publications

References 0 publications

Facial nerve electroneurography: variability in normal subjects

Facial nerve electroneurography: variability in normal subjects

Facial electroneurography in Bell's palsy: variability in the early stage and comparison between interpretation methods

Decompression of the labyrinthine segment of the facial nerve in acoustic neuroma surgery: a consideration for minimizing postoperative delayed facial nerve dysfunction

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