Effect of Bumetanide on Facial Nerve Regeneration in Rat Model.

OBJECTIVE: We investigated the effects of bumetanide alone and in combination with dexamethasone on facial nerve regeneration in rats with facial paralysis. STUDY DESIGN: A prospective controlled animal study. SETTING: An animal laboratory. SUBJECTS AND METHODS: Facial paralysis was induced in 32 Wistar rats that we then divided into 4 groups: group 1, control; group 2, bumetanide; group 3, dexamethasone; group 4, bumetanide and dexamethasone. Electroneurography was performed 1, 2, and 4 weeks later, and nerve regeneration was evaluated by electron and light microscopy and Western blotting in week 4. RESULTS: Regarding the comparison between preoperative values and week 4, the latency difference in group 1 (1.25 milliseconds) was significantly higher than those of groups 2 to 4 (0.56, 0.34, and 0.10 milliseconds, respectively; P = .001). The latency increment in groups 2 and 3 was higher than that of group 4 (P = .002 and P = .046) in week 4, whereas groups 2 and 3 did not differ significantly (P = .291). Amplitude difference was not statistically significant from week 4 among all groups (all P > .05). The number of myelinated axons was significantly higher in all treatment groups than in the control group (P = .001). Axon number and intensity were significantly higher in group 4 as compared with groups 2 and 3 (P = .009, P = .005). CONCLUSION: After primary neurorrhaphy, dexamethasone and bumetanide alone promoted nerve recovery based on electrophysiologic and histologic measures. Combination therapy was, however, superior.

Occipitalis muscle: using for repetitive facial nerve stimulation in myasthenia gravis.

Repetitive nerve stimulation (RNS) is a highly sensitive electrophysiological test used for diagnosing myasthenia gravis (MG). Here, we evaluated electrodiagnostic value of RNS using facial nerve and occipitalis muscle. Patients with generalized MG were included. Clinical findings were assessed. RNS test was performed on occipitalis, nasalis, trapezius, abductor policis brevis (APB) and abductor digiti minimi (ADM) muscles. Twenty-five (78%) patients had relevant decrement during RNS test of at least one muscle. Nasalis muscle had the highest diagnostic potential (68.8%), followed by trapezius (53.3%), occipitalis (50%), APB (30%) and ADM (16.7%) muscles. There was not a significant relationship between clinical symptoms and facial RNS recorded on occipitalis muscle. In conclusion, we suggest that facial RNS recording over occipitalis muscle can be added in electrodiagnosis of MG because of cranial nerve innervation and proximal location. Facial RNS recording over occipitalis muscle provides a good choice under the conditions such as atrophy, cosmetic surgery, or botulinum toxin application in which nasalis muscle is unavailable for use.

Effects of Melatonin and Dexamethasone on Facial Nerve Neurorrhaphy.

OBJECTIVES: To investigate the effects of topical and systemic administrations of melatonin and dexamethasone on facial nerve regeneration. MATERIALS AND METHODS: In total, 50 male albino Wistar rats underwent facial nerve axotomy and neurorrhaphy. The animals were divided into 5 groups: control, topical melatonin, systemic melatonin, topical dexamethasone, and systemic dexamethasone. Nerve conduction studies were performed preoperatively and at 3, 6, 9, and 12 weeks after drug administrations. Amplitude and latency of the compound muscle action potentials were recorded. Coapted facial nerves were investigated under light and electron microscopy. Nerve diameter, axon diameter, and myelin thickness were recorded quantitatively. RESULTS: Amplitudes decreased and latencies increased in both the melatonin and dexamethasone groups. At the final examination, the electrophysiological evidence of facial nerve degeneration was not significantly different between the groups. Histopathological examinations revealed the largest nerve diameter in the melatonin groups, followed by the dexamethasone and control groups (p<0.05). Axon diameter of the control group was smaller than those of the melatonin (topical and systemic) and topical dexamethasone groups (p<0.05). The melatonin groups had almost normal myelin ultrastructure. CONCLUSION: Electrophysiological evaluation did not reveal any potential benefit of dexamethasone and melatonin in contrast to histopathological examination, which revealed beneficial effects of melatonin in particular. These agents may increase the regeneration of facial nerves, but electrophysiological evidence of regeneration may appear later.

Repetitive Facial Nerve Stimulation Using Occipitalis Muscle.

PURPOSE: We aimed to evaluate the reliability and reproducibility of repetitive nerve stimulation recorded on occipitalis muscle by comparing recordings on nasalis muscle in healthy subjects. METHODS: A total of 23 healthy subjects (mean age: 44.7 ± 13.8 years) underwent detailed neurological examination and repetitive nerve stimulation using nasalis and occipitalis muscles. Amplitude and area percentage changes of compound muscle action potentials (CMAPs) after repetitive nerve stimulation with different frequency were compared between right and left sides and between recordings on nasalis and occipitalis muscles. RESULTS: Comparisons of percentage amplitude changes of nasalis and occipitalis CMAPs showed no differences (+0.1% ± 3.8% vs. +1.4% ± 3.9%, P = 0.129). Average area percentage change of nasalis CMAPs was 0.3% ± 19.0%, whereas the value of occipitalis CMAP was +2.8% ± 15.2% (P = 0.851). Comparisons of nasalis and occipitalis CMAPs values showed no differences. CONCLUSIONS: The repetitive nerve stimulation recorded on occipitalis muscle is simple, easy to apply, noninvasive, consistent, and reproducible.

Electrophysiologic Evaluation of the Facial Nerve and Blink Reflex Pathways in Asymptomatic Cochlear Implant Users.

OBJECTIVE: To evaluate the functional integrity of the facial nerve and blink reflex (BR) pathways in asymptomatic patients who underwent cochlear implantation (CI). STUDY DESIGN: Case series with planned data collection. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Twenty-four deafened patients with unilateral CI who had no complications were enrolled. Bilateral compound muscle action potentials (CMAPs) of the facial nerve were recorded over the nasalis and occipitalis muscles, whereas BR responses were recorded over the orbicularis oculi after supraorbital nerve stimulation. All recordings were performed when the external part of the implant was in place (CIp) and after its removal (CIr), except occipitalis recordings, which were performed only after removal. The amplitude and latency of CMAP were measured to evaluate the axonal integrity of the zygomatic and posterior branches of the facial nerve. Latency, amplitude, and duration of the BR were measured to investigate the integrity of trigeminofacial connections. RESULTS: The amplitude and latency of CMAP over the nasalis muscle were bilaterally normal, and the difference between CIp and CIr was not statistically significant. No CMAP of the occipitalis muscle was recorded in 4 (16.7%) patients, and low-amplitude responses were recorded on the implant side of 20 (83.3%). Amplitudes of the contralateral R2 response were higher in the CIp condition versus the CIr condition (P = .031). There were no differences among other BR components. CONCLUSION: During functioning of the CI system, excitability of the facial circuit may increase either through the facial motor nucleus or through removal of the inhibitory effect of the descending pathway.

Human olfactory stem cells for injured facial nerve reconstruction in a rat model.

BACKGROUND: The purpose of this study was to show the efficacy of olfactory stem cells for injured facial nerve reconstruction in a rat model. METHODS: Olfactory stem cells were isolated from the olfactory mucosa of human participants. A 2-mm excision was performed on the right facial nerve of all rats. Reconstruction was performed with a conduit in group 1 (n = 9); a conduit and phosphate-buffered saline in group 2 (n = 9); and a conduit and labeled olfactory stem cell in group 3 (n = 9). Rats were followed for whisker movements and electroneuronography (ENoG) analyses. RESULTS: The whisker-movement scores for group 3 were significantly different from other groups (p < .001). ENoG showed that the amplitude values for group 3 were significantly different from group 1 and group 2 (p = .030; p < .001). Group 3 showed marked olfactory stem cell under a fluorescence microscope. CONCLUSION: This study suggests that olfactory stem cells may be used as a potent cellular therapy for accelerating the regeneration of peripheral nerve injuries. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2011-E2020, 2016.

A novel muscle for electroneurography in peripheral facial palsy: occipitalis.

Electroneurography (ENoG) is one of the most objective tests in grading the damage and prediction of prognosis in peripheral facial palsy (PFP). We aimed to determine temporal changes of ENoG recorded over occipitalis muscle in acute idiopathic PFP. Consecutive 21 patients with unilateral acute idiopathic PFP and age- and sex-matched 15 healthy volunteers were included in the study. Nasal and occipital ENoG values were recorded once in the control group and the same procedure was repeated daily between the second and eight days of the disorder in the PFP group. Occipital ENoG value began to increase on the third day while nasal ENoG value was still within the normal range (27.04 vs 7.69 %, p = 0.0001). In the fourth, fifth and sixth days, occipital ENoG value was significantly high compared to nasal ENoG value (p = 0.0001 for each day) whereas nasal and occipital ENoG values were very similar in the seventh and eighth days (p = 0.181 and p = 0.584, respectively). Our study presents further support for technical possibility of occipital ENoG which may reflect the degree of fiber degeneration earlier than the nasalis muscle in PFP.

Effects of Open Technique Rhinoplasty on Mimicry: Electroneurographic Evaluation.

OBJECTIVE: This study was designed to investigate the effects of open technique rhinoplasty on facial nerve terminal branches more concerned with mimicry via electroneurography (ENoG). METHODS: Twenty patients ages between 24 and 36 years were included in the study. Five nasal mimicry muscles were used to evaluate axonal loss of the facial nerve: bilateral transverse nasal, levator labii superioris alaeque nasi (LLSAN), and procerus muscles of all patients were evaluated preoperatively and postoperative third month by ENoG. The patients that have abnormalities regarding the amplitude and latency at third month were reevaluated at sixth month postoperatively. RESULTS: Mean latencies of the facial nerve were calculated to be increased for all muscles at third postoperative month, but this increase was significant only for left LLSAN (P = 0.002). Amplitudes of the facial nerve decreased in all of the groups, but this decrease was not significant (P > 0.05). Two patients with exceptionally long latency facial nerve response of transverse nasal muscle and 11 muscle recordings with abnormal low amplitudes of the facial nerve at the third month was reevaluated at sixth postoperative month and the values were improved. CONCLUSIONS: This study demonstrated that facial nerve integrity is minimally affected after rhinoplasty, yet all affected muscles were recovered on the long term.

Effect of anti-adhesive barrier use on laryngotracheal movement after total thyroidectomy: an electrophysiological study.

Impairment of laryngotracheal movement is a possible complication after total thyroidectomy. Here, we aimed to investigate the frequency and extent of impairment of laryngotracheal movement after total thyroidectomy and the effect of anti-adhesive barrier hyaluronic acid-carboxymethylcellulose membrane positioning between strap muscles and laryngotracheal complex on deglutition. The study design is prospective clinical study. Istanbul Training and Research Hospital, Laboratory of Electrophysiology, Istanbul Training and Research Hospital. The patients who underwent total thyroidectomy were selected and dichotomized according to use of seprafilm. Each group consisted of 8 female patients. All patients were assessed clinically and electrophysiologically in the pre/postop period. Electrophysiological investigations included cricopharyngeal muscle (CPM) electromyography (EMG), submental EMG, single bolus analysis [foreburst, reburst, swallowing (pause) patterns], laryngotracheal movement analysis and results were compared between two groups. CPM EMG was normal in both groups. Duration of submental muscle activity during dry and 15 cc water swallowing was similar between two groups (P = 0.751). Pause duration was shorter in group with seprafilm (P < 0.01). Dysphagia limit was 15 cc in both groups. The fore/rebound bursts duration, the time of laryngeal elevation, closure and suspension were similar (P = 0.954). We concluded that use of seprafilm between larynx and strap muscles during total thyroidectomy does not have any adverse effects on swallowing. Anti-adhesive barrier can be used safely during thyroid surgery.

Provocative F wave in the diagnosis of nonspecific neurogenic-type thoracic outlet syndrome.

OBJECTIVE: Thoracic outlet syndrome (TOS) is defined as a constellation of clinical symptoms caused by the entrapment of neurovascular structures (subclavian vessels and the brachial plexus) en route to the upper limb via the superior thoracic outlet. Nonspecific neurogenic TOS is not easy to diagnose because there is no investigational technique that has proven to be the diagnostic gold standard. DESIGN: In this study, our aim was to investigate the role of provocative F response in the diagnosis of nonspecific neurogenic TOS. F wave analysis of median and ulnar nerves in neutral and provocative maneuvers was carried out in 21 patients with a clinical diagnosis of nonspecific neurogenic TOS and in 15 healthy volunteers. RESULTS: All findings were within reference range in both groups, and no statistical difference was noted among subject groups, with or without provocative maneuvers. CONCLUSIONS: We conclude that the nonspecific neurogenic TOS is a temporary compression process that does not result in a structural damage on the nerve; therefore, significant electrophysiologic changes are not elicited.

Cricopharyngeal muscle electromyography findings in patients with gastroesophageal reflux disease.

OBJECTIVE: To analyze the grade of reflux and the behavior of the cricopharyngeal muscle (CPM) in patients with gastroesophageal reflux (GER) by means of electromyographic (EMG) analysis of CPM. STUDY DESIGN: Prospective clinical study. SETTING: Istanbul Training and Research Hospital. SUBJECT AND METHODS: Motor unit potential (MUP) recordings and kinesiological recordings of CPM were performed using a concentric needle electrode during dry material swallowing and 3-, 5-, and 10-mL water swallowing. Twenty-four patients with GER were compared with 21 healthy volunteers. RESULTS: GER was mild in 15 patients and moderate-to-severe in 9 patients. MUP recordings were normal in both groups during the preswallowing/postswallowing periods. Kinesiological investigations revealed that the number of patients who did not show a preswallow EMG burst had a positive correlation with the severity of reflux and the amount of liquid swallowed. Rebound bursts were observed in the patient and the control groups. Duration of preswallow and rebound bursts was similar in all groups. Duration of swallowing was shorter in mild GER patients compared with healthy volunteers and moderate-to-severe GER patients. Piecemeal deglutition during 10-mL liquid swallowing was higher in moderate-to-severe GER patients. We also found a positive correlation between the number of swallows and the severity of reflux. CONCLUSION: Needle EMG of the upper esophageal sphincter was normal in GER patients. Kinesiological evaluations showed increased piecemeal deglutition and number of swallows that correlated positively with the severity of GER.

Topographic description of an alternative insertion technique for percutaneous approach of cricopharyngeus muscle electromyography: a cadaveric and clinical study.

BACKGROUND: Cricopharyngeus is the only muscle for which electromyography is used in the differential diagnosis of swallowing disorders. Because of some practical difficulties, electrophysiologic tests for this muscle are not performed routinely. Thus we aimed to describe an alternative topographic way to reach the muscle easily. METHODS: On 10 cadavers, a spinal needle (20 G) and on 37 patients a concentric needle electrode (26 G) were used. The needle was inserted percutaneous at the level of the superior border of the cricoid cartilage, anterior to the anterior border of the sternocleidomastoid muscle at 60 degrees angle to the frontal plane in the posteromedial direction. RESULTS: We reached the muscle in all cadavers. In all of the patients, the needle entered the muscle on the first attempt; that was confirmed by electromyographic responses. CONCLUSION: Our results show that this method can be useful for the practical application of cricopharyngeus muscle electromyography.

Electromyographic and electroneurographic changes in internal nasal muscles after endonasal and external rhinoplasty.

BACKGROUND: Anatomical structures of the nose (including muscles) are elevated, sutured, or reshaped during rhinoplasty. Electromyography and electroneurography are the objective electrophysiologic tests performed for the direct measurement of nasal muscle function. OBJECTIVES: The authors investigate the predictive values and functional status of nasal muscles during voluntary facial and nasal movements following open and closed rhinoplasty. METHODS: In 48 patients who underwent rhinoplasty, surface electrodes were placed to preoperatively and postoperatively measure nasal muscle function with electromyography and electroneurography. Results were analyzed according to whether the patient had undergone open or closed rhinoplasty. RESULTS: Electroneurography amplitudes were decreased postoperatively on both sides, in both groups. This increase was statistically significant (p < .001). Electromyography-recorded amplitude of nasal muscle contraction tension significantly decreased postoperatively in response to all voluntary movements in two cases in the closed rhinoplasty group (6.6%) and in two cases in the open rhinoplasty group (11.1%). In essence, the activity strength of the nasal muscles decreased postoperatively for some patients. The mean differences between the two groups were not statistically significant (p = .280). CONCLUSIONS: The data showed no meaningful difference in injury to the nasal muscular layer between open and closed rhinoplasty.