Influence of superior laryngeal nerve injury on glottal configuration/function of thyroidectomy-induced unilateral vocal fold paralysis.

Recurrent laryngeal nerve (RLN) injury may induce unilateral vocal fold paralysis (UVFP). During thyroidectomy, the most common cause of UVFP, the superior laryngeal nerve (SLN), is also at risk of injury. In the literature, the influence of SLN injury on glottal configuration and function in patients with UVFP remains controversial. The present study investigates SLN injury influence on glottal configuration and function in patients with UVFP after thyroidectomy. Prospective controlled study. Tertiary medical center. The SLN and RLN function of 34 patients with UVFP after thyroidectomy was determined by laryngeal electromyography. The subjects were dichotomized into the isolated RLN injury group (n = 26) or the concurrent SLN/RLN injury group (n = 8). We evaluated glottal angle and paralyzed vocal fold shape during inspiration, normalized glottal gap area, and glottal shape during phonation. The glottal function measurements included voice acoustic and aerodynamic analyses and the Voice Handicap Index. The aforementioned parameters of the RLN and concurrent SLN/RLN injury groups were compared. There were no statistical differences in glottal configuration such as glottal angle, paralyzed vocal fold shape, normalized glottal gap area, and glottal shape between the RLN and concurrent SLN/RLN injury groups. There were also no significant differences in other glottal function analyses including fundamental frequency, mean airflow rate, phonation quotient, maximal phonation time, and Voice Handicap Index. In the present study, we did not find any evidence that SLN injury could significantly influence the glottal configuration and function in patients with UVFP.

De Virgilio A ，Chang MH ，Jiang RS ，Wang CP ，Wu SH ，Liu SA ，Wang CC ... -  《-》

Short-term treatment results for unilateral vocal fold palsy induced by mediastinal lesions.

Vocal fold paralysis (VFP) is a frequent complication of surgery of mediastinal structures. This study evaluated the characteristics and short-term treatment outcomes of injection laryngoplasty for unilateral VFP (UVFP) induced by mediastinal lesions. The enrolled patients (n = 60) underwent injection laryngoplasty once because of UVFP and were divided into two groups according to cause (group A, thyroidectomy and group B, mediastinal surgery). Voice analysis was performed preoperatively and at 1 month postoperatively. The glottal gap; the Grade, Roughness, Breathiness, Asthenia, and Strain scale; acoustic analysis; and aerodynamic results were measured. Group A and group B comprised eight and 52 patients, respectively. Group B patients were older than group A patients (P < 0.05). The injected volume in group B (0.91 ± 0.23 mL) was larger than that of group A (0.38 ± 0.17 mL; P = 0.022). Group B (13.35 ± 4.69 units) showed a larger glottal gap than group A (6.64 ± 4.05 units; P = 0.017), and the glottal gap decreased after the procedure. In both groups, most preoperative acoustic parameters except roughness improved after injection laryngoplasty. The preoperative maximum phonation time of group B (2.87 ± 1.11 seconds) was shorter than that of group A (7.04 ± 2.58 seconds), and it improved after injection. Mean airflow rate improved significantly after injection in both groups. Mediastinal lesion-induced UVFP is associated with a larger glottal gap than that caused by an injury induced by thyroidectomy. Despite large glottal gap, injection laryngoplasty improves voice outcomes in such types of UVFP.

Lee YS ，Kim YH ，Kwon M ，Ryu IS ，Jung GE ，Kim ST ，Roh JL ，Choi SH ，Kim SY ，Nam SY ... -  《-》

Laryngeal electromyography-guided hyaluronic acid vocal fold injection for unilateral vocal fold paralysis: a prospective long-term follow-up outcome report.

Wang CC ，Chang MH ，Jiang RS ，Lai HC ，De Virgilio A ，Wang CP ，Wu SH ，Liu SA ，Liang KL ... -  《-》

Quantitative laryngeal electromyography assessment of cricothyroid function in patients with unilateral vocal fold paralysis.

Determination of superior laryngeal nerve (SLN) involvement in addition to recurrent laryngeal nerve (RLN) paralysis in patients with unilateral vocal fold paralysis (UVFP) relies on traditional, qualitative laryngeal electromyography (LEMG) examination. It is necessary to develop a quantitative measurement that reflects the degree of denervation of the cricothyroid (CT) muscle. The present study aimed to establish a standard quantitative assessment of CT function in patients with UVFP by measuring the turn frequency. Case series study performed in an otolaryngology outpatient clinic. Twenty healthy subjects and 103 patients with UVFP were recruited. The main outcome measures for the patients included acoustic analysis using traditional LEMG examination, quantitative LEMG analysis, and acoustic analysis based on fundamental frequency contours. Acoustic reliability was examined in the healthy subjects, and the peak fundamental frequency in an upward glissando showed good test-retest reliability, especially for the offset fundamental frequency. LEMG indicated that 33 patients had RLN and SLN lesions (RLN+SLN group) and 70 had only RLN lesions (RLN group). When patients produced a standard upward glissando sound, the peak turn frequency reflecting the recruitment of the CT muscle was significantly lower in the RLN+SLN group compared with the RLN group (406±256 vs. 778±238 Hz; P<.001). We conclude that quantitative measurement of the interference pattern when voicing a standard upward glissando sound may provide a feasible reflection of the degree of a SLN injury. 4.

Fang TJ ，Pei YC ，Hsin LJ ，Lin WN ，Lee LA ，Li HY ，Wong AM ... -  《-》

Neuromuscular compensation mechanisms in vocal fold paralysis and paresis.

Vocal fold paresis and paralysis are common conditions. Treatment options include augmentation laryngoplasty and voice therapy. The optimal management for this condition is unclear. The objective of this study was to assess possible neuromuscular compensation mechanisms that could potentially be used in the treatment of vocal fold paresis and paralysis. In vivo canine model. In an in vivo canine model, we examined three conditions: 1) unilateral right recurrent laryngeal nerve (RLN) paresis and paralysis, 2) unilateral superior laryngeal nerve (SLN) paralysis, and 3) unilateral vagal nerve paresis and paralysis. Phonatory acoustics and aerodynamics were measured in each of these conditions. Effective compensation was defined as improved acoustic and aerodynamic profile. The most effective compensation for all conditions was increasing RLN activation and decreasing glottal gap. Increasing RLN activation increased the percentage of possible phonatory conditions that achieved phonation onset. SLN activation generally led to decreased number of total phonation onset conditions within each category. Differential effects of SLN (cricothyroid [CT] muscle) activation were seen. Ipsilateral SLN activation could compensate for RLN paralysis; normal CT compensated well in unilateral SLN paralysis; and in vagal paresis/paralysis, contralateral SLN and RLN displayed antagonistic relationships. Methods to improve glottal closure should be the primary treatment for large glottal gaps. Neuromuscular compensation is possible for paresis. This study provides insights into possible compensatory mechanisms in vocal fold paresis and paralysis. NA Laryngoscope, 127:1633-1638, 2017.

Dewan K ，Vahabzadeh-Hagh A ，Soofer D ，Chhetri DK ... -  《-》