High variability of facial muscle innervation by facial nerve branches: A prospective electrostimulation study.

OBJECTIVES/HYPOTHESIS: To examine by intraoperative electric stimulation which peripheral facial nerve (FN) branches are functionally connected to which facial muscle functions. STUDY DESIGN: Single-center prospective clinical study. METHODS: Seven patients whose peripheral FN branching was exposed during parotidectomy under FN monitoring received a systematic electrostimulation of each branch starting with 0.1 mA and stepwise increase to 2 mA with a frequency of 3 Hz. The electrostimulation and the facial and neck movements were video recorded simultaneously and evaluated independently by two investigators. RESULTS: A uniform functional allocation of specific peripheral FN branches to a specific mimic movement was not possible. Stimulation of the whole spectrum of branches of the temporofacial division could lead to eye closure (orbicularis oculi muscle function). Stimulation of the spectrum of nerve branches of the cervicofacial division could lead to reactions in the midface (nasal and zygomatic muscles) as well as around the mouth (orbicularis oris and depressor anguli oris muscle function). Frontal and eye region were exclusively supplied by the temporofacial division. The region of the mouth and the neck was exclusively supplied by the cervicofacial division. Nose and zygomatic region were mainly supplied by the temporofacial division, but some patients had also nerve branches of the cervicofacial division functionally supplying the nasal and zygomatic region. CONCLUSIONS: FN branches distal to temporofacial and cervicofacial division are not necessarily covered by common facial nerve monitoring. Future bionic devices will need a patient-specific evaluation to stimulate the correct peripheral nerve branches to trigger distinct muscle functions. LEVEL OF EVIDENCE: 4 Laryngoscope, 127:1288-1295, 2017.

The effective stimulating pulse for restoration of blink function in unilateral facial nerve paralysis rabbits, verified by a simple FES system.

The trains of 200 ms biphasic square pulses with the width of 9 ms delivered at 50 Hz were found to be the most suitable and effective mean as stimulation in FES system of restoring the blink function in unilateral facial nerve paralysis rabbit model. FES system is a reliable tool for these patients. Facial paralysis affects thousands of people every year. Many will have long term facial difficulties and the loss of the ability to blink the eye, which can lead to potential loss of the eye. Although many treatments exist, no one approach corrects all the deficits associated with the loss of orbicularis oculi function. FES is a means of providing movement in paralysed muscles to assist with practical activities and one possible way of restoring blink and other functions in these patients. Although some previous researches had investigated the effect of simple FES system on restoration of paralyzed facial muscles, there is still controversy about the appropriate details of the most effective stimulating pulses, such as the frequency, wave pattern and pulse width. Our aim is to find out the parameters of the most appropriate and effective stimulatin verify it by a simple FES system. 24 healthy adult male New Zealand white rabbits were accepted the surgery of right side facial nerve main trunk transaction under general anesthesia as the unilateral facial nerve paralysis models. The platinum tungsten alloy electrodes were implanted in orbicularis oculi muscle. The parameters of stimulus pulses were set to a 200 ms biphasic pulse with different waveforms (square, sine and triangle), different frequencies (25, 50, 100 Hz) and different widths from 1 to 9 ms. Next, we set up a simple FES system to verify the previous results as the stimulus signal. We observed the movement of the both sides of eyelid when eye blink induced by different kinds of pulses. In all animals, the three kinds of waveforms pulse with frequency of 25 Hz could not evoke the smooth blink movement. But the pulses with frequency of 50 and 100 Hz can achieve this effect. The voltage threshold of the square pulse was lower than that of the sine pulse and triangle pulse. With the increase of pulse width from 1 to 9 ms, the voltage threshold decreased gradually. The voltage threshold of the pulse with frequency of 100 Hz was obviously lower than that of 50 Hz. But the amount of total charge of the stimulation pulse of 100 Hz was significantly more than that of 50 Hz. In addition, when the FES system was turned on, the eye blink on the affected side with the stimulation pulses that were set by the previous step results was successfully aroused by the blink movement as a trigger on the contralateral.

Lagophthalmos after facial palsy: current therapeutic options.

As the facial nerve carries sensory, motor and parasympathetic fibres involved in facial muscle innervation, facial palsy results in functional and cosmetic impairment. It can result from a wide variety of causes like infectious processes, trauma, neoplasms, autoimmune diseases, and most commonly Bell's palsy, but it can also be of iatrogenic origin. The main ophthalmic sequel is lagophthalmos. The increased surface exposure increases the risk of keratitis, corneal ulceration, and potentially loss of vision. Treatment options are wide; some are temporary, some permanent. In addition to gold standard and traditional therapies and procedures, new options are being proposed aiming to improve not only lagophthalmos but also the quality of life of these patients.

Surgical anatomy of the orbital region, local anesthesia and general considerations.

Orbital region may be divided into four sectors: medial canthus, lateral canthus, lower lid and upper lid. A vertical section of a lid shows 5 layers: skin, subcutaneous tissue with orbicularis muscle, fibrous layer (tarsus-aponeurosis), plain fibers muscle layer (Muller's), conjunctiva. The first two layers form the "anterior lamella" and the other ones the "posterior lamella", divided by the grey line. In this review Authors describe with all details the orbital region and the eyelid layers, considering the most important concepts for surgery. Finally they resume basics of local anesthesia in ophthalmoplastic surgery.

Myoelectric signals of levator palpebrae superioris as a trigger for FES to restore the paralyzed eyelid.

Some closed loop FES systems have been designed to restore the blinking function of facial paralysis patients. All of them used myoelectric signal of orbicularis oculi at the normal side as the trigger to stimulate the paralyzed side. They were limited to the one side facial paralysis. Here we proposed that the myoelectric signal of levator palpebrae superioris could be used as the trigger to stimulate the paralyzed orbicularis oculi. Because the levator palpebrae superioris and the innervating nerve are intact, the myoelectric signal of the paralyzed side still could be used as the trigger. It will be more acceptable for the patients and have the potential to resolve the bilateral facial paralysis.

Regional nerve block of the upper eyelid in oculoplastic surgery.

PURPOSE: To establish the efficacy of a regional nerve block of the upper eyelid and its effect on levator motor function. METHODS: Forty-one patients underwent surgery on 54 upper eyelids by one surgeon, after administration of a regional nerve block at the supraorbital notch. The amount of pain experienced by patients due to the local anesthetic injection and surgery was determined by using visual analogue scores. The effect of the local anesthetic injection on levator function was determined by comparing the measured levator function prior to and following administration. Any complications attributable to the regional sensory nerve block were recorded. RESULTS: Ninety-two percent of patients found the injection painless, and the rest reported negligible pain. The mean pain score for the injection was 2 (SD 1.3, range 0-6). The mean pain score for the surgery was 0.3 (SD 0.6, range 0-3). No significant difference was found in levator function prior to and following the injection (pre-function: 14.4 mm, post-function: 13.4 mm, p=0.01). One patient had hematoma formation at the site of injection. CONCLUSIONS: A regional nerve block of the upper eyelid achieves effective sensory anesthesia,without compromising motor function. This helps in an accurate assessment of intraoperative height during upper lid surgery.

Neuronal premotor networks involved in eyelid responses: retrograde transneuronal tracing with rabies virus from the orbicularis oculi muscle in the rat.

Retrograde transneuronal tracing with rabies virus from the right orbicularis oculi muscle was used to identify neural networks underlying spontaneous, reflex, and learned blinks. The kinetics of viral transfer was studied at sequential 12 hr intervals between 3 and 5 d after inoculation. Rabies virus immunolabeling was combined with the immunohistochemical detection of choline acetyltransferase expression in brainstem motoneurons or Fluoro-Ruby injections in the rubrospinal tract. Virus uptake involved exclusively orbicularis oculi motoneurons in the dorsolateral division of the facial nucleus. At 3-3.5 d, transneuronal transfer involved premotor interneurons of trigeminal, auditory, and vestibular reflex pathways (in medullary and pontine reticular formation, trigeminal nuclei, periolivary and ventral cochlear nuclei, and medial vestibular nuclei), motor pathways (dorsolateral quadrant of contralateral red nucleus and pararubral area), deep cerebellar nuclei (lateral portion of interpositus nucleus and dorsolateral hump ipsilaterally), limbic relays (parabrachial and Kölliker-Fuse nuclei), and oculomotor structures involved in eye-eyelid coordination (oculomotor nucleus, supraoculomotor area, and interstitial nucleus of Cajal). At 4 d, higher order neurons were revealed in trigeminal, auditory, vestibular, and deep cerebellar nuclei (medial, interpositus, and lateral), oculomotor and visual-related structures (Darkschewitsch, nucleus of the posterior commissure, deep layers of superior colliculus, and pretectal area), lateral hypothalamus, and cerebral cortex (particularly in parietal areas). At 4.5 and 5 d the labeling of higher order neurons occurred in hypothalamus, cerebral cortex, and blink-related areas of cerebellar cortex. These results provide a comprehensive picture of the premotor networks mediating reflex, voluntary, and limbic-related eyelid responses and highlight potential sites of motor learning in eyelid classical conditioning.

Multi-channel orbicularis oculi stimulation to restore eye-blink function in facial paralysis.

Facial paralysis due to facial nerve injury results in the loss of function of the muscles of the hemiface. The most serious complication in extreme cases is the loss of vision. In this study, we compared the effectiveness of single- and multiple-channel electrical stimulation to restore a complete and cosmetically acceptable eye blink. We established bilateral orbicularis oculi muscle (OOM) paralysis in eight dogs; the OOM of one side was directly stimulated using single-channel electrical stimulation and the opposite side was stimulated using multi-channel electrical stimulation. The changes in the palpebral fissure and complete palpebral closure were measured. The difference in current intensities between the multi-channel and single-channel simulation groups was significant, while only multi-channel stimulation produced complete eyelid closure. The latest electronic stimulation circuitry with high-quality implantable electrodes will make it possible to regulate precisely OOM contractions and thus generate complete and cosmetically acceptable eye-blink motion in patients with facial paralysis.

Discharge profiles of abducens, accessory abducens, and orbicularis oculi motoneurons during reflex and conditioned blinks in alert cats.

The discharge profiles of identified abducens, accessory abducens, and orbicularis oculi motoneurons have been recorded extra- and intracellularly in alert behaving cats during spontaneous, reflexively evoked, and classically conditioned eyelid responses. The movement of the upper lid and the electromyographic activity of the orbicularis oculi muscle also were recorded. Animals were conditioned by short, weak air puffs or 350-ms tones as conditioned stimuli (CS) and long, strong air puffs as unconditioned stimulus (US) using both trace and delayed conditioning paradigms. Motoneurons were identified by antidromic activation from their respective cranial nerves. Orbicularis oculi and accessory abducens motoneurons fired an early, double burst of action potentials (at 4-6 and 10-16 ms) in response to air puffs or to the electrical stimulation of the supraorbital nerve. Orbicularis oculi, but not accessory abducens, motoneurons fired in response to flash and tone presentations. Only 10-15% of recorded abducens motoneurons fired a late, weak burst after air puff, supraorbital nerve, and flash stimulations. Spontaneous fasciculations of the orbicularis oculi muscle and the activity of single orbicularis oculi motoneurons that generated them also were recorded. The activation of orbicularis oculi motoneurons during the acquisition of classically conditioned eyelid responses happened in a gradual, sequential manner. Initially, some putative excitatory synaptic potentials were observed in the time window corresponding to the CS-US interval; by the second to the fourth conditioning session, some isolated action potentials appeared that increased in number until some small movements were noticed in eyelid position traces. No accessory abducens motoneuron fired and no abducens motoneuron modified their discharge rate for conditioned eyelid responses. The firing of orbicularis oculi motoneurons was related linearly to lid velocity during reflex blinks but to lid position during conditioned responses, a fact indicating the different neural origin and coding of both types of motor commands. The power spectra of both reflex and conditioned lid responses showed a dominant peak at approximately 20 Hz. The wavy appearance of both reflex and conditioned eyelid responses was clearly the result of the high phasic activity of orbicularis oculi motor units. Orbicularis oculi motoneuron membrane potentials oscillated at approximately 20 Hz after supraorbital nerve stimulation and during other reflex and conditioned eyelid movements. The oscillation seemed to be the result of both intrinsic (spike afterhyperpolarization lasting approximately 50 ms, and late depolarizations) and extrinsic properties of the motoneuronal pool and of the circuits involved in eye blinks.

Quantal organization of reflex and conditioned eyelid responses.

Quantal organization of reflex and conditioned eyelid responses. J. Neurophysiol. 78: 2518-2530, 1997. Upper lid movements and the electromyographic activity of the orbicularis oculi muscle were recorded in behaving cats during spontaneous and experimentally evoked reflex blinks, and conditioned eyelid responses. Reflex blinks evoked by the presentation of air puffs, flashes, or tones consisted of a fast downward lid movement followed by late, small downward waves, recurring at approximately 50-ms intervals. The latency, maximum amplitude, peak velocity, and number of late waves depended on the modality, intensity, and duration of the evoking stimulus. The power spectra of acceleration records indicated a dominant frequency of approximately 20 Hz for air puff-evoked blinks. Flashes and tones usually evoked small and easily fatigable reflex responses of lower dominant frequencies (14-17 and 9-11 Hz, respectively). A basic approximately 20-Hz oscillation was also noticed during lid fixation, and ramplike lid displacements evoked by optokinetic stimuli. Five classical conditioning paradigms were used to analyze the frequency-domain properties of conditioned eyelid responses. These learned lid movements differed in latency, maximum amplitude, and profile smoothness depending on the modality (air puff, tone), intensity (weak, strong), and presentation site (ipsi-, contralateral to the unconditioned stimulus) of the conditioned stimulus. It was found that the characteristic ramplike profile of a conditioned response was not smooth, but appeared to be formed by a succession of small waves at a dominant frequency of approximately 20 Hz. The amplitude (and number) of the constituting waves depended on the characteristics of the conditioned stimulus and on the time interval until unconditioned stimulus presentation. Thus conditioned responses seemed to be formed from lid displacements of 2-6 degrees in amplitude and approximately 50 ms in duration, which increased in number throughout conditioning sessions, until a complete (i.e., lid closing) conditioned response was reached. It is suggested that a approximately 20-Hz oscillator underlies the generation of reflex and conditioned eyelid responses. The oscillator is susceptible to being neurally modulated to modify the velocity of a given quantum of movement, and the total duration of the lid response. Learned eyelid movements are probably the result of a successively longer release of the oscillator as a function of the temporal-spatial needs of the motor response.

Discharge of identified deep cerebellar nuclei neurons related to eye blinks in the alert cat.

The activity of identified cerebellar nuclear neurons was recorded in the alert cat during blinks induced by corneal air puffs, light flashes and tones. Eyelid response to air puffs consisted of an early (16.5 +/- 2.7 ms) downward movement followed by two to three late downward steps. Blinks induced by flashes or tones presented longer latencies (52.6 +/- 4.8 and 50.1 +/- 8.0 ms). Type A neurons (n = 86) increased their spike activity in coincidence with the beginning of the blink, regardless of the stimulus modality. The late eyelid downward responses were accompanied by corresponding increases in the firing rate of the neuron. Type A neurons were activated mostly from the red nucleus (48/86) or the restiform body (24/86). Type B neurons (n = 30) fired a brief burst of spikes slightly preceding the blink, followed by a noticeable decrease in their firing rate. As for type A, the discharge response of type B neurons was always the same regardless of the sensory modality. These neurons were activated from the red nucleus (18/30), oculomotor complex (6/30) and restiform body (6/30). Although no precise temporal coupling was found between the beginning of the neuronal response and the start of either the stimulus or the motor response, linear regression analysis demonstrated significant relationships between mean firing rate of type A and B neurons and eyelid position, velocity and/or acceleration. Deep cerebellar nuclei neurons presented here seem to be directly involved in the execution of reflexively induced blinks following the smaller details of eyelid motor performance. The opposite behavior of type A and B cells suggests an interplay of reciprocal actions to determine the ongoing displacements of the lid. Finally, the cerebellum seems to influence blinks through a spread action on many brainstem sites and not exclusively on the red nucleus.

Blink reflex recovery after electrical stimulation of the reinnervated orbicularis oculi muscle in dogs.

The paralytic lagophthalmos following palpebral nerve neurotmesis and consequent peripheral denervation of the orbicularis oculi muscle is often associated with harmful effects on the exposed cornea. This study investigated how daily electrical stimulation affects the blink reflex recovery of this muscle after its reinnervation. Six dogs underwent unilateral facial nerve neurotmesis with immediate epineurial repair of the palpebral nerve. Three dogs were randomly chosen to receive electrical stimulation of the reinnervated orbicularis oculi muscles for 75 days. The remaining 3 dogs were controls (nonstimulated muscles). During the study, the reinnervated orbicularis oculi muscle electrophysiology and blink reflex recovery were investigated. The Student's t test was used for statistical analysis. The results can be summarized as follows: (1) between 30 and 50 days, the minimum mean stimulus intensities evoking complete up-per palpebral closure of the stimulated muscles were significantly lower than those of the nonstimulated muscles (p less than 0.01) and (2) the stimulated muscles recovered complete closure of the interpalpebral fissure (blink reflex) at 49.6 days, significantly earlier (p less than 0.01) than the nonstimulated muscles (72.6 days). It is concluded that daily electrical stimulation of the orbicularis oculi muscles, if started immediately after epineurial repair of the palpebral nerve neurotmesis, promotes a faster blink reflex recovery in the dog model.

[Comparison of the effectiveness of bupivacaine with xylocaine and xylocaine alone used for akinesia and retrobulbar anesthesia in cataract surgery]. / Porównanie skutecznosci bupivacainy z xylocaina i samej xylocainy zastosowanych do akinezji i znieczulania pozagalkowego w chirurgii zacmy.

The paper presents a comparison of the efficacy of Bupivacaine with Xylocaine and Xylocaine alone used for retrobulbar injection and akinesia in cataract surgery. Two groups comprising 50 patients each were subjected to evaluation. The results obtained encourage to put into practice the mixture of Bupivacaine with Xylocaine for local anaesthesia in cataract operations.

Chronic progressive spinobulbar spasticity with disturbance of voluntary eyelid closure. Report of a case with special reference to MRI and electrophysiological findings.

We describe a 56-year-old man who had a progressive pseudobulbar palsy, spastic tetraparesis, forced laughing and disturbance of voluntary eyelid closure, and was clinically compatible with chronic progressive spinobulbar spasticity. Magnetic resonance images (MRI) revealed atrophy of the bilateral motor cortices and single photon emission tomography after intravenous injection of N-isopropyl-p-iodoamphetamine iodine-123 (IMP-SPECT) showed hyporadioactivity in the same regions. Electrophysiological studies on supranuclear paralysis of eyelid closure demonstrated that so-called apraxia and motor impersistence coexisted and that in attempts to keep the eyelid closed the inhibition of basal activity of the levator palpebrae superioris muscle and activation of the orbicularis oculi muscle were insufficient, indicating the impaired reciprocity of these ocular muscles. The corresponding lesion of these eyelid symptoms was considered to be the bilateral motor cortices.

Facial paralysis rehabilitation: retraining selective muscle control.

Traumatic facial paralysis can be improved with surgical techniques but alone will not restore full function. EMG sensory (bio) feedback can, however, facilitate rehabilitation. Four cases are described using a combined treatment technique of EMG, behavioural modification and specific action exercises. Retraining of eyelid control was also accomplished. Standardized evaluation methods are described. All four patients showed improvement, despite the failure of traditional retraining methods.

[Specific local anesthesia: pharmacology, administration and clinical use (author's transl)]. / Gezielte Lokalanästhesie. Pharmakologie, Applikation und klinische Anwendung.

In order to achieve an optimal combination of principal and side effects of the various drugs used in local anesthesia, a thorough knowledge of pharmacology, anatomy and physiology is essential. The properties of the most commonly used short-acting (Lidocain) medium (Mepivacain) and long-acting (Bupivacain) local anesthetics are described, as well as the effect of the vasoconstrictors Adrenalin and Ornipressin, and of hyaluronidase. The advantages and drawbacks of the different application modalities are discussed. In clinical practice, the surgeon has to be aware of his particular local anesthetic needs at any given time and any stage of the operation, and should attempt to create ideal conditions by careful selection, combination and application of the different drugs. The choice is relatively easy in operations on the globe, the eye muscles and the lacrimal drainage system. In major lid operations, however, greater differentiation in the selection of drugs and methods of application is advisable.