No abstract available.
Arteries* ; Laryngeal Nerves* ; Thyroid Gland*

No abstract available.
Animals ; Brain Stem* ; Brain* ; Cats* ; Laryngeal Nerves*

PURPOSE: The most important function of the larynx is airway protection which is provided through a polysynaptic reflex closure triggered by the receptors in the glottic and supraglottic mucosa, evoking the reflex contraction of the laryngeal muscles especially by strong adduction of vocal cords. Based on the hypotheses that central facilitation is essential for this bilateral adductor reflex and that its disturbance can result in weakened laryngeal closure, we designed this study to elucidate the effect of central facilitation on this protective reflex. MATERIALS AND METHODS: Seven adult, 20 kg mongrel dogs underwent evoked response laryngeal electromyography under 0.5 to 1.0 MAC (minimum alveolar concentration) isoflurane anesthesia. The internal branch of the superior laryngeal nerve was stimulated through bipolar platinum-iridium electrodes, and recording electrodes were positioned in the ipsilateral and contralateral thyroarytenoid muscles. RESULTS: Ipsilateral reflex closure was consistantly recorded regardless of anesthetic levels. However, contralateral reflex responses disappeared as anesthetic levels were deepened. Additionally, late responses (R2) were detected in one animal at lower level of anesthesia. CONCLUSIONS: Deepened level of anesthesia affects central facilitation and results in the loss of the crossed adductor reflex, predisposing to a weakened glottic closure response. Precise understanding of this effect may possibly provide a way to prevent aspiration in unconscious patients.
Anesthesia/methods ; Animals ; Dogs ; Glottis/*physiology ; Laryngeal Nerves/physiology ; *Reflex

Neurofibroma of the larynx is a rare disease. Endolaryngeal neurofibromas may take place as an isolated lesion or a part of multiple neurofibromatosis (von Recklinghausen's disease). A case of endolaryngeal neurofibroma was the first reported by Suchanek in 1925. Following the first report, there have been sporadic reports of endolaryngeal neurofibroma When the lesion is in the larynx, the major site is the aryepiglottic fold or the arytenoid, because the branch of the superior laryngeal nerve is involved. Rarely, a vocal cord is also concerned. Surgical excision is the treatment of choice. We report a case of isolated neurofibroma arising from the right true vocal cord.
Laryngeal Nerves ; Larynx ; Neurofibroma* ; Neurofibromatoses ; Rare Diseases ; Vocal Cords*

BACKGROUND AND OBJECTIVES: The inferior parathyroid glands receive their blood supply from the inferior thyroid artery. The anatomic relationship of this artery and the recurrent laryngeal nerve can assume three different patterns. To maintain the vascular supply of the inferior parathyroid glands during central neck dissection, we considered the anatomic relationship of these structures in our surgical approach. MATERIALS AND METHODS: Fibrofatty tissue in the central neck compartment was removed by dissection proceeding along the recurrent laryngeal nerve. During the dissection, care was taken not to injure the vascular supply of the inferior parathyroid gland. RESULTS: For an inferior parathyroid gland that receives its blood supply from the posterolateral vascular pedicle, preservation is achieved by performing the dissection along the recurrence laryngeal nerve on the gland's medial side. In patients in whom the inferior thyroid artery travels deep to the right recurrent laryngeal nerve, such that the right parathyroid gland receives its blood supply from the posteromedial vascular pedicle, central neck dissection should be performed carefully along the lateral side of the gland to preserve the pedicle. CONCLUSION: Preservation of inferior parathyroid gland function requires a detailed understanding of the anatomic relationship between the inferior thyroid artery and recurrent laryngeal nerve. The direction of the dissection along the nerve should be adjusted according to its anatomic relationship to the inferior thyroid artery.
Arteries ; Humans ; Hypoparathyroidism ; Laryngeal Nerves ; Neck ; Neck Dissection ; Parathyroid Glands* ; Recurrence ; Recurrent Laryngeal Nerve ; Thyroid Gland

Humans ; Laryngeal Nerves ; Recurrent Laryngeal Nerve ; surgery ; Vocal Cord Paralysis ; surgery

BACKGROUND AND OBJECTIVES: ObjectivesZZRecurrent laryngeal nerve (RLN) injury is a potentially debilitating complication of thyroid surgery. In re-operative thyroid surgery, the risk of vocal fold paralysis increases significantly. This study evaluated the efficiency of intraoperative RLN monitoring using an electromyography (EMG) tube in an re-operative thyroid surgery and the prediction of postoperative neural function from the relationship between the intraoperative neuromonitoring response and postoperative vocal fold function. SUBJECTS AND METHOD: Sixty-nine patients undergoing reoperative thyroid surgery were divided into two groups: 37 patients underwent reoperative thyroid surgery with intraoperative neuromonitoring (EMG group) and 32 patients underwent reoperative thyroid surgery without intraoperative neuromonitoring (no EMG group). The prevalence of transient and permanent vocal fold paralysis was evaluated in each group. In addition, the sensitivity, specificity, and negative and positive predictive values of intraoperative neuromonitoring were evaluated. RESULTS: Transient and permanent vocal fold paralysis occurred in 8.1% (3/37) and 2.7% (1/37) of the EMG group and 12.5% (4/32) and 6.3% (2/32) of the no EMG group, respectively. The negative and positive predictive values of intraoperative neuromonitoring using an EMG tube in predicting postoperative vocal fold function were 100% and 57.1%, respectively. CONCLUSION: Although the differences were not significant, intraoperative neuromonitoring using the EMG tube resulted in shorter operating time, and less transient and permanent vocal fold paralysis during reoperative thyroid surgery. Intraoperative neuromonitoring using an EMG tube for reoperative thyroid surgery may be useful for preserving the postoperative vocal fold function.
Electromyography ; Humans ; Laryngeal Nerves ; Paralysis ; Prevalence ; Recurrent Laryngeal Nerve ; Sensitivity and Specificity ; Thyroid Gland ; Vocal Cords

BACKGROUND AND OBJECTIVES: Injury of recurrent laryngeal nerve is one of the major complications of thyroidectomy. One of the treatment options, which has met with some criticism, may be the repair of the injured nerve. This study was designed to investigate the efficiency of the neurorrhaphy of the injured recurrent laryngeal nerve with voice and videostroboscopic analysis. MATERIALS AND METHODS: For the injured recurrent laryngeal nerve, ansa hypoglossi-recurrent laryngeal nerve anastomosis has been performed in 6 patients, and direct end to end anastomosis has been performed in 4 patients. Postoperative parameters of perceptual analysis, acoustic analysis, aerodynamic study, and videostroboscopy after 6 months were compared with those of 11 patients whose recurrent laryngeal nerves were resected and left without neurorrhaphy. RESULTS: Perceptual breathy vocal quality and the aerodynamic parameters were better in anastomosed group, but there were no differences in the acoustic parameters. Medialization of vocal cord and the glottic closure was better in anastomosed group. No patient of the anastomosed group experienced dyspnea due to synkinesis. CONCLUSION: The results of this study indicates that the neurorrhaphy of injured recurrent laryngeal nerve is effective in improving the glottic closure, but unsatisfactory in achieving symmetric glottic tension and mucosa wave during phonation.
Acoustics ; Dyspnea ; Humans ; Laryngeal Nerves ; Mucous Membrane ; Phonation ; Recurrent Laryngeal Nerve* ; Synkinesis ; Thyroidectomy* ; Vocal Cords ; Voice*

OBJECTIVE: To analyze the clinical characteristics between neurogenic and non-neurogenic cause of vocal cord immobility (VCI). METHODS: The researchers retrospectively reviewed clinical data of patients who underwent laryngeal electromyography (LEMG). LEMG was performed in the bilateral cricothyroid and thyroarytenoid muscles. A total of 137 patients were enrolled from 2011 to 2016, and they were assigned to either the neurogenic or non-neurogenic VCI group, according to the LEMG results. The clinical characteristics were compared between the two groups and a subgroup analysis was done in the neurogenic group. RESULTS: Among the 137 subjects, 94 patients had nerve injury. There were no differences between the neurogenic and non-neurogenic group in terms of demographic data, underlying disease except cancer, and premorbid events. In general characteristics, cancer was significantly higher in the neurogenic group than non-neurogenic group (p=0.001). In the clinical findings, the impaired high pitched ‘e’ sound and aspiration symptoms were significantly higher in neurogenic group (p=0.039 for impaired high pitched ‘e’ sound; p=0.021 for aspiration symptoms), and sore throat was more common in the non-neurogenic group (p=0.014). In the subgroup analysis of neurogenic group, hoarseness was more common in recurrent laryngeal neuropathy group than superior laryngeal neuropathy group (p=0.018). CONCLUSION: In patients with suspected vocal cord palsy, impaired high pitched ‘e’ sound and aspiration symptoms were more common in group with neurogenic cause of VCI. Hoarseness was more frequent in subjects with recurrent laryngeal neuropathy. Thorough clinical evaluation and LEMG are important to differentiate underlying cause of VCI.
Electromyography ; Hoarseness ; Humans ; Laryngeal Muscles ; Laryngeal Nerves ; Pharyngitis ; Recurrent Laryngeal Nerve ; Retrospective Studies ; Vocal Cord Paralysis ; Vocal Cords*

PURPOSE: Vocal symptoms have been reported after thyroidectomy and even in the absence of injury to the recurrent laryngeal nerve or the external branch of the superior laryngeal nerve. The aim of this prospective study was to evaluate the subjective and objective voice changes in patients without laryngeal nerve injury after thyroidectomy. METHODS: The subjects had undergone total thyroidectomy for differentiated thyroid carcinoma from November 2007 to December 2008. Twenty-eight subjects (males: 8, females: 20) were selected for this study. Voice analysis was prospectively evaluated in the subjects at the time of preoperation and postoperation (10.8 months for the males and 11.7 months for the females). A subjective analysis was done using the visual analogue scale (VAS, 0: no symptom, 10: severe symptoms) and objective analyses were determined by several parameters such as the fundamental frequency (Fo), jitter, shimmer and the noise to harmonic ratio (NHR) using the multi-dimensional voice program. Maximum phonation time (MPT)was performed as an aerodynamic test. RESULTS: 3 patients (37.5%) among the males and 14 patients (70%) among the females had subjective postoperative voice change. The VAS showed a significant difference for the females (0 to 1.25±0.97, P<0.001), whereas no changes were shown for the males (0 to 0.88±1.25, P>0.05). The vocal parameters (Fo, jitter, shimmer, NHR) and MPT showed no significant changes for both the males and females (P>0.05). CONCLUSION: Subjective voice changes may occur after thyroidectomy without laryngeal nerve injury. Surgeons should take possible voice changes into consideration when informing patients before thyroidectomy.
Female ; Humans ; Laryngeal Nerve Injuries ; Laryngeal Nerves ; Male ; Noise ; Phonation ; Prospective Studies ; Recurrent Laryngeal Nerve ; Surgeons ; Thyroid Neoplasms ; Thyroidectomy* ; Voice