Effects of arytenoid adduction on laryngeal function following ansa cervicalis nerve transfer for vocal fold paralysis in an in vivo canine model

Laryngeal reinnervation with the ansa cervicalis has been proposed as a treatment for human unilateral vocal fold paralysis (UVFP). This study tested the assumption that results from reinnervation could be improved if combined with medialization surgery. Six canine subjects underwent recurrent laryngeal nerve section and reinnervation with a branch of the ansa cervicalis. After reinnervation, vocal function was assessed before and after arytenoid adduction. Although laryngeal function improved significantly following reinnervation, results were significantly enhanced by the addition of medialization surgery. The implications for the treatment of human unilateral vocal fold paralysis are discussed.     

Experimental Study on Reinnervation of Vocal Cord Adductors With the Ansa Cervicalis

The purpose of this study was to reestablish the adduction of the paralyzed vocal cord through reinnervation of the adductor muscles for unilateral vocal cord paralysis. In nine dogs, the adductor branch of the recurrent laryngeal nerve was anastomosed to the main branch of the ansa cervicalis. Six months later, various techniques of observation showed that seven of nine cases had excellent to good adduction during whining. Adduction was caused by reinnervation of the adductor muscles from the ansa cervicalis as demonstrated by laryngeal spontaneous and evoked electromyography, contraction tension, and various histologic findings. Therefore, the new technique could be a good treatment of unilateral vocal cord paralysis.     

A novel modification of the ansa to recurrent laryngeal nerve reinnervation procedure for young children

Vocal ford paralysis is a condition often seen in otolaryngologic adult and pediatric clinics. We report a case we believe to be the youngest child to undergo ansa cervicalis (ansa) to recurrent laryngeal nerve (RLN) reinnervation for unilateral vocal fold paralysis. We have included the preoperative and postoperative videostroboscopic and acoustic findings. The acoustic data shows improvement and is consistent with the patient's improved voice quality. Most notably the patient's voice quality is less raspy and his volume has improved while subjectively requiring less effort.     

Configuration of the glottis in laryngeal paralysis. I: Clinical study

It is widely accepted in the American literature that the cricothyroid muscle is responsible for the paramedian position of the vocal fold in recurrent laryngeal nerve paralysis. However, support in the literature for this theory is not conclusive, and the cadaveric vocal fold position expected after lesions of the vagus nerve has also been reported in patients with an intact superior laryngeal nerve. This study compares the configuration of the glottis in patients with unilateral paralysis due to known lesions of either the recurrent laryngeal or vagus nerve. Normal subjects were studied as controls. Results indicate that the alteration of glottic configuration in laryngeal paralysis cannot be adequately characterized by standard terms of vocal fold position. The paralyzed vocal fold is shortened, with anterior rotation of the arytenoid. Patients with vagus nerve lesions had a statistically insignificant tendency for a more lateral vocal fold position, but a discrete difference in position between the two groups was not identified. This study also confirms prior observations that paralyzed vocal folds are frequently not denervated. These findings have significant implications for management of laryngeal paralysis.     

Cervical osteophytes causing vocal fold paralysis: case report and literature review

Objectives: To increase awareness of cervical osteophytes as an extremely rare cause of recurrent laryngeal nerve palsy; to outline the clinical approach to patients with unilateral vocal fold paralysis and to provide an update on the current management of osteoarthritis and osteophytes. Case report: An elderly man presented with right unilateral vocal fold immobility and a small phonatory gap. By a diagnosis of exclusion, a cervical osteophyte at the level of the sixth and seventh cervical vertebrae was shown to be the cause. The patient responded to speech therapy and no further intervention was required. Method: A literature review, using Medline, identified only one previously published case of vocal fold paralysis due to osteophytes secondary to osteoarthritis. Conclusion: The aetiology of unilateral paralysis of the hemilarynx must be fully investigated, as the innervating system has a protracted course, particularly on the left side. Degenerative cervical spine disease, although rare, should be considered as part of the differential diagnosis.     

Acoustic and perceptual evaluation of laryngeal reinnervation by ansa cervicalis transfer

Objectives/Hypothesis: To evaluate the acoustic and perceptual results of laryngeal reinnervation with ansa cervicalis to recurrent laryngeal nerve anastomosis. Study Design: Retrospective study of voice samples from 12 patients with unilateral recurrent laryngeal nerve paralysis, treated with ansa cervicalis to recurrent laryngeal nerve anastomosis. Samples were recorded before surgery and at least 8 months after surgery. Methods: The samples were subjected to several acoustic analyses sensitive to paralytic dysphonia, including cepstral peak prominence, noise-to-harmonics ratio, and measures of frequency and amplitude perturbation. The voice samples from the patients were randomized with age- and sexmatched samples from normal subjects and judged by trained listeners for overall dysphonia, roughness, breathiness, asthenia, and strain. The preoperative and postoperative results were compared statistically, and the postoperative results were compared with the matched normal subjects. Results: As a group, the patients showed improvement (P < .05) in cepstral peak prominence, frequency perturbation, and perceptual judgments of overall dysphonia, breathiness, and asthenia. The best results occurred in patients with isolated vocal fold paralysis. The postoperative group as a whole did not improve to the level seen in matched normals. Suboptimal results were seen primarily in patients with untreated laryngeal or extralaryngeal pathology beyond the laryngeal paralysis. Conclusions: These data suggest that laryngeal reinnervation has the potential to bring about a return to normal or near-normal voice in patients with isolated unilateral vocal fold paralysis.     

Unilateral vocal fold adductor paralysis after tracheal intubation

Vocal fold immobility is a relatively rare complication that can occur after tracheal intubation. Differential diagnoses include a rare clinical entity called unilateral vocal fold adductor paralysis in which only branches entering the thyroarytenoid and lateral cricoarytenoid muscles of the recurrent laryngeal nerve become paralyzed. Computed tomography and laryngeal electromyography are required to distinguish this condition from others such as cricoarytenoid dislocation/subluxation. Here, we describe two patients who developed vocal fold adductor paralysis after intubation. Patient 1 was a 56-year-old man who underwent living-donor liver transplantation and was extubated on day 7 after surgery. Patient 2 was a 52-year-old man who received life support measures including intubation due to ventricular fibrillation, and was extubated two days later. Both were hoarse soon after extubation. Endoscopic laryngeal examination revealed normal abduction and insufficient adduction of paralyzed vocal folds. Computed tomography ruled out cricoarytenoid dislocation/subluxation and laryngeal electromyography confirmed unilateral vocal fold adductor paralysis. Laryngologists should consider this rare pathogenesis.     

Laryngeal reinnervation for unilateral traumatic recurrent laryngeal nerve injuries]

OBJECTIVE: To investigate 5 procedures of laryngeal reinnervation for unilateral vocal cord paralysis induced by traumatic recurrent laryngeal nerve injury. METHODS: 35 cases were selected for our study, all patients had unilateral recurrent laryngeal nerve injury, including 8 for nerve decompression, 6 for end to end anastomosis of recurrent laryngeal nerve, 16 for main branch of ansa cervicalis anastomosis to recurrent laryngeal nerve, 3 for nerve muscular pedicle and 2 for nerve implantation. All cases have been subjected to preoperative and postoperative voice recording, acoustic analysis, videolaryngoscopy, strobscopy and electromyography. RESULTS: It is found the adductory and abductory motion of the vocal cord restored in 5 cases with less than 4 months course who received nerve decompression. Although functional motion of vocal cord was not seen in two patients who received nerve decompression with a course longer than 4 months and one less than 4 months, and in all cases who received ansa cervicalis anastomosis and end to end anastomosis of recurrent laryngeal nerve, these procedures resulted in medialization of vocal cord and the mass and tension of the reinnervated vocal cord may become much the same as the contralateral normal vocal cord, thus resuming symmetric vibration of the vocal cords and physiological phonation. Nerve muscular pedicle technique and nerve implantation enabled adductory muscles to be reinnervated, thus improving severe hoarseness, but they didn't restore normal voice. CONCLUSIONS: (1) Nerve decompression seems to be the best procedure in laryngeal reinnervation; (2) Main branch of ansa cervicalis technique raises satisfactory reinnervation of adductor muscles; (3) Selection of the laryngeal reinnervation protocols should depend on the course, severity and type of nerve injury.     

Intraoperative laryngeal electromyography in children with vocal fold immobility: a simplified technique

OBJECTIVES: The primary objective of this study was to determine whether a simplified technique for intraoperative laryngeal electromyography was feasible using standard nerve integrity monitoring electrodes and audiovisual digital recording equipment. Our secondary objective was to determine if laryngeal electromyography data provided any additional information that significantly influenced patient management. METHODS: Between February 2006 and February 2007, 10 children referred to our institution with vocal fold immobility underwent intraoperative laryngeal electromyography of the thyroarytenoid muscles. A retrospective chart review of these 10 patients was performed after institutional review board approval. RESULTS: Standard nerve integrity monitoring electrodes can be used to perform intraoperative laryngeal electromyography of the thyroarytenoid muscles in children. In 5 of 10 cases reviewed, data from laryngeal electromyography recordings meaningfully influenced the care of children with vocal fold immobility and affected clinical decision-making, sometimes altering management strategies. In the remaining 5 children, data supported clinical impressions but did not alter treatment plans. Two children with idiopathic bilateral vocal fold paralysis initially presented with a lack of electrical activity on one or both sides but went on to develop motor unit action potentials that preceded recovery of motion in both vocal folds. CONCLUSIONS: Our findings suggest that standard nerve monitoring equipment can be used to perform intraoperative laryngeal electromyography and that electromyographic data can assist clinicians in the management of complex patients. Additionally, there may be a role for the use of serial intraoperative measurements in predicting recovery from vocal fold paralysis in the pediatric age group.     

Ansa cervicalis-to-recurrent laryngeal nerve anastomosis for unilateral vocal fold paralysis: experience of a single institution

OBJECTIVES: One treatment option for unilateral vocal fold paralysis (UVFP) is ansa cervicalis-to-recurrent laryngeal nerve (ansa-RLN) anastomosis to provide reinnervation to the affected vocal fold. The advantages of this treatment approach are that it 1) provides vocal fold tone, bulk, and tension, 2) is technically simple, and 3) does not preclude other medialization procedures. We present all patients who have undergone ansa-RLN anastomosis for UVFP at our institution. METHODS: An Institutional Review Board-approved retrospective chart review was performed to include all patients who had undergone an ansa-RLN anastomosis procedure for UVFP at our institution. Data from clinical and endoscopic laryngoscopy with stroboscopy were recorded. Statistical analysis was performed on visual and perceptual vocal data. RESULTS: A total of 46 patients were included in the study. Stroboscopic analysis and perceptual vocal evaluation was performed in a blinded fashion on the 21 patients who had preoperative and postoperative stroboscopy. Severity, roughness, breathiness, and strain all improved significantly over time. Glottic closure, vocal fold edge, and supraglottic effort all significantly improved after operation. Of the 38 patients with at least 3 months of follow-up, all except 1 demonstrated evidence of reinnervation. CONCLUSIONS: This technique for treating UVFP results in significant improvements in patients' voice and on visual examination.     

Long-term result of the new endoscopic vocal fold medialization surgical technique for laryngeal palsy

OBJECTIVE: The conventional surgical method for a case of unilateral laryngeal nerve paralysis with large glottal gap requires an external cervical incision. In the present study, we developed an endoscopic technique of vocal fold medialization that can make the external incision unnecessary. This procedure of autologous transplantation of fascia into the vocal fold (ATFV) was developed for the successful treatment of unilateral laryngeal nerve paralysis. However, the method seemed to be effective only for patients with a relatively mild glottal gap. STUDY DESIGN AND METHODS: In the present study, we modified the method of medialization using the ATFV technique to obtain effective closure of a large glottal gap. To overcome this difficulty, an attempt was made to extend the site of transplantation more posteriorly so as to adduct the vocal process of the arytenoid cartilage in the body of the vocal fold. RESULTS: This new technique was applied to eight cases of patients with unilateral laryngeal paralysis with severe dysphonia. None of the patients showed any evidence of falling off of the graft. Elongation of the maximum phonation time and a decrease in airflow rate during phonation were obtained with improvement in voice quality in all patients 1 year after the surgery. CONCLUSIONS: This method, with its less invasive approach, proved to be useful for the treatment of large glottal gap due to unilateral laryngeal nerve paralysis.     

Combined arytenoid adduction and laryngeal reinnervation in the treatment of vocal fold paralysis

OBJECTIVE/HYPOTHESIS: Glottal closure and symmetrical thyroarytenoid stiffness are two important functional characteristics of normal phonatory posture. In the treatment of unilateral vocal cord paralysis, vocal fold medialization improves closure, facilitating entrainment of both vocal folds for improved phonation, and reinnervation is purported to maintain vocal fold bulk and stiffness. A combination of medialization and reinnervation would be expected to further improve vocal quality over medialization alone. STUDY DESIGN: A retrospective review of preoperative and postoperative voice analysis on all patients who underwent arytenoid adduction alone (adduction group) or combined arytenoid adduction and ansa cervicalis to recurrent laryngeal nerve anastomosis (combined group) between 1989 and 1995 for the treatment of unilateral vocal cord paralysis. Patients without postoperative voice analysis were invited back for its completion. A perceptual analysis was designed and completed. METHODS: Videostroboscopic measures of glottal closure, mucosal wave, and symmetry were rated. Aerodynamic parameters of laryngeal airflow and subglottic pressure were measured. A 2-second segment of sustained vowel was used for perceptual analysis by means of a panel of voice professionals and a rating system. Statistical calculations were performed at a significance level of P = .05. RESULTS: There were 9 patients in the adduction group and 10 patients in the combined group. Closure and mucosal wave improved significantly in both groups. Airflow decreased in both groups, but the decrease reached statistical significance only in the adduction group. Subglottic pressure remained unchanged in both groups. Both groups had significant perceptual improvement of voice quality. In all tested parameters the extent of improvement was similar in both groups. CONCLUSION: The role of laryngeal reinnervation in the treatment of unilateral vocal cord paralysis remains to be established.     

Experimental study on simultaneous selective reinnervation of the adductors and the abductor muscle for the treatment of the laryngeal paralysis

OBJECTIVE: The aim of this study is to estimate the value of a new surgical procedure in the treatment of the chronic unilateral laryngeal paralysis. METHODS: The recurrent laryngeal nerve of the left side of the dog was totally cut and served as a model of unilateral laryngeal paralysis at the first step of the research. The adductor and abductor branches of the recurrent laryngeal nerve were then, selected and cut. Afterwards, they were micro-sutured respectively with one branch of ansa cervicalis and phrenic nerve immediately (group 1) and 4 months later (group 2). Six months after this reinnervation, the laryngeal physiologic function of the lateral crico-arytenoid muscle (LCA) and the posterior crico-arytenoid muscle (PCA) have been checked by the methods of electromyography (EMG) and direct laryngoscopy. All the data have been analysed by the statistic methods. RESULTS: Among all the data of EMG, only the wave amplitude of action potential of the LCA muscle of the group 2 was diminished (p < 0.05). Under the direct laryngoscopy, the adductor movement of the left vocal cord of the group 2 was also lightly reduced. But the adductor and abductor movements of the left vocal cord were synchronous with the mouvements of the right vocal cord. CONCLUSION: Though the result of nervous reinnervation of a four month's laryngeal paralysis was not so good by comparison with that of an immediate reinnervation, this surgical procedure can however on the clinical point of view, reach a satisfactory level. The duration maximum of the reinnervation operation after laryngeal paralysis, is, at the present, not clear. It is necessary for us to make further studies.     

Photoelectric measurement of laryngeal paralyses correlated with videostroboscopy

Photoglottography and electroglottography are relatively noninvasive techniques that provide detailed information about vocal fold vibration. However, few significant clinical applications have been made by correlating photoelectric waveforms to specific pathologic changes in laryngeal vibration. Videostroboscopy has recently been used to document vibratory patterns of laryngeal paralyses in a canine model of phonation. A study of PGG and EGG waveforms correlated with videostroboscopy in an in-vivo canine model of phonation with simulated unilateral recurrent or superior laryngeal nerve paralysis is presented. The shift quotient--a new glottographic parameter which identifies flaccid laryngeal paralyses--is presented.     

Configuration of the glottis in laryngeal paralysis. II: Animal experiments

It is widely believed that in isolated recurrent laryngeal nerve paralysis, the paralyzed vocal fold assumes a median or paramedian position, due to the action of the cricothyroid muscle. A review of the literature reveals that support for this theory is not conclusive and, in particular, experiments indicate that the cricothyroid muscle does not appreciably affect vocal fold position in acute paralysis. The research in this study compares the configuration of the glottis in chronic unilateral recurrent laryngeal nerve paralysis in cats, with and without concomitant denervation of the cricothyroid muscle. Results indicate that vocal fold position is not determined by the cricothyroid muscle. Incomplete denervation of intrinsic laryngeal muscles as well as synkinetic reinnervation appear to be significant factors in determining vocal fold position in chronic laryngeal paralysis.     

The cricothyroid muscle does not influence vocal fold position in laryngeal paralysis

The status of the cricothyroid muscle, which is innervated by the superior laryngeal nerve, is believed to influence the vocal fold position in laryngeal paralysis. It is believed that isolated lesions of the recurrent laryngeal nerve generally result in the paralyzed vocal fold assuming a paramedian position but that with lesions of both the superior and recurrent laryngeal nerves, a more lateral (intermediate or cadaveric) vocal fold position can be expected. Twenty-six consecutive patients with unilateral vocal fold paralysis underwent transnasal fiberoptic laryngoscopy (TFL) and laryngeal electromyography (LEMG). By TFL, the vocal fold positions were paramedian in 8 patients, intermediate in 7, and lateral in 11. By LEMG, 13 patients had isolated recurrent laryngeal nerve lesions and 13 patients had combined (superior and recurrent laryngeal nerve) lesions. There was no correlation between the vocal fold position and the status of the cricothyroid muscle, i.e., the status of the cricothyroid muscle by LEMG did not predict the vocal fold position nor did the vocal fold position by TFL predict the site of lesion. In addition, we investigated the possibility that the degree of thyroarytenoid muscle recruitment (tone) might correlate with vocal fold position, but no relation was found. We conclude that 1. the cricothyroid muscle does not predictably influence the position of the vocal fold in unilateral paralysis; 2. thyroarytenoid muscle recruitment (tone) does not appear to influence vocal fold position; and 3. still unidentified and unknown factors may be responsible for determining vocal fold position in laryngeal paralysis.     

Vocal fold paresis and paralysis

Diagnosis and treatment of the immobile or hypomobile vocal fold are challenging for the otolaryngologist. True paralysis and paresis result from vocal fold denervation secondary to injury to the laryngeal or vagus nerve. Vocal fold paresis or paralysis may be unilateral or bilateral, central or peripheral, and it may involve the recurrent laryngeal nerve, superior laryngeal nerve, or both. The physician's first responsibility in any case of vocal fold paresis or paralysis is to confirm the diagnosis and be certain that the laryngeal motion impairment is not caused by arytenoid cartilage dislocation or subluxation, cricoarytenoid arthritis or ankylosis, neoplasm, or other mechanical causes. Strobovideolaryngoscopy, endoscopy, radiologic and laboratory studies, and electromyography are all useful diagnostic tools.     

Cervical osteophytes presenting as unilateral vocal fold paralysis and dysphagia.

Any process involving either the vagus nerve, its recurrent laryngeal branch or the external branch of the superior laryngeal nerve may cause paralysis of the vocal fold. The most common cause is neoplasm. Clinically, the patients often present with a hoarse, breathy voice as well as symptoms of aspiration. The following represents a unique case of unilateral vocal fold paralysis and dysphagia caused by a degenerative disease of the cervical spine, resluting in extrinsic compression of the recurrent laryngeal nerve.     

Echo-Planar Magnetic Resonance Imaging of Deglutitive Vocal Fold Closure: Normal and Pathologic Patterns of Displacement

Abnormalities of vocal fold closure during deglutition predispose to aspiration due to impairment of airway protection. Conventional assessment of deglutitive vocal fold motion with laryngoscopy does not permit visualization through a complete adduction-abduction cycle. We determined spatiotemporal patterns of deglutitive vocal fold adduction through echo-planar magnetic resonance imaging in 15 normal volunteers and 6 patients with vocal fold paralysis. In normal volunteers, deglutitive vocal fold adduction was synchronized with laryngeal elevation, with complete vocal fold closure at the apex. Patients with unilateral vocal fold paralysis demonstrated reduced elevation and medial movement of the involved vocal fold. At maximal laryngeal elevation the uninvolved vocal fold attained a position superior to the paralyzed fold, resulting in level differences and an interglottic gap. Patients with bilateral vocal fold paralysis demonstrated reduced elevation and medial movement of both vocal folds. These findings indicate that normal and abnormal patterns of vocal fold displacement can be distinguished noninvasively through the use of echo-planar imaging. Laryngoscope, 106:568-572, 1996     

两种术式治疗单侧声带麻痹的比较

目的 研究单侧声带麻痹的合适手术治疗方法及其疗效的客观评价。方法 对２３例行喉支架术（９例）及喉神经再支配术（１４例）的患者于术前及术后从声音评估、频谱分析、喉镜及喉肌电检查等几方面进行了比较观察。结果 喉支架术近远期效果均良好，但在远期效果中，又以能恢复声带厚度、弹性及肌张力的喉神经再支配术为佳，且此术式治疗声带麻痹时间较短的患者效果更好。结论 两种术式均是治疗单侧声带麻痹的有效方法，但应根据患