Lidocaine block of the recurrent laryngeal nerve in adductor spasmodic dysphonia: a multidimensional assessment

OBJECTIVES/HYPOTHESIS: Lidocaine block of the recurrent laryngeal nerve (RLN) has been reported as a procedure for surgical selection of patients with adductor spasmodic dysphonia (ADSD). However, its effects on phonation have not been rigorously assessed in a prospective fashion using strict entry criteria and multiple measures of phonatory function. This investigation assessed the phonatory effects of RLN lidocaine block in ADSD to explore its potential as a diagnostic tool. STUDY DESIGN: Single group, pre/postexperimental trial. METHODS: Twenty-one consecutive patients with suspected ADSD underwent unilateral RLN block, causing temporary ipsilateral vocal fold paralysis. Voices were recorded before and during the block. Patients completed self-ratings of overall level of dysphonia severity, vocal effort, and laryngeal tightness. Blinded listeners completed auditory-perceptual ratings, and the frequency of phonatory breaks was acoustically analyzed. RESULTS: During the block, patients reported significant reductions on overall severity (P = .045), vocal effort (P < .001), and laryngeal tightness (P = .002). Listeners rated the voices during the block as significantly more breathy (P < .001), less strained (P < .001), and less severe (P = .059). Acoustic analysis confirmed significantly fewer phonatory breaks during the block (P < .001). Patient-based ratings of improvement were more consistent than listener ratings, and reduction in overall severity correlated with perceived breathiness. CONCLUSIONS: Although individuals varied in their outcomes, group results suggest that response to RLN lidocaine block warrants further study as a possible diagnostic tool in ADSD.     

Task specificity in adductor spasmodic dysphonia versus muscle tension dysphonia

OBJECTIVES: Adductor spasmodic dysphonia (ADSD) has been characterized as a "task specific" laryngeal dystonia, meaning that the severity of dysphonia varies depending on the demands of the vocal task. Voice produced in connected speech as compared with sustained vowels is said to provoke more frequent and severe laryngeal spasms. This study examined the diagnostic value of "task specificity" as a marker of ADSD and its potential to differentiate ADSD from muscle tension dysphonia (MTD), a functional voice disorder that can often masquerade as ADSD. STUDY DESIGN: Case-control study. METHODS: Five listeners, blinded to the purpose of the study, used a 10 cm visual analogue scale to rate dysphonia severity of subjects with ADSD (n = 36) and MTD (n = 45) producing either connected speech or a sustained vowel "ah."RESULTS: In ADSD, dysphonia severity for connected speech (M = 6.22 cm, SD = 2.56) was rated significantly more severe than sustained vowel productions (M = 4.8 cm, SD = 2.8 [t (35) = 3.67, P < .001]). In MTD, however, no significant difference in severity was observed for the connected speech sample (M = 5.98 cm, SD = 2.83 versus the sustained vowel M = 5.86 cm, SD = 2.87 [t (44) = 0.378, P = .707]). The receiver operating characteristic (ROC) curve, an index of the accuracy of task specificity as a diagnostic marker, revealed that a 1 cm difference criterion correctly identified 53% of ADSD cases (sensitivity) and 76% of MTD cases (specificity) (chi2 (1) = 6.88, P = .0087). CONCLUSIONS: Reduced dysphonia severity during sustained vowels supports task specificity in ADSD but not MTD and highlights a valuable diagnostic marker whose recognition should contribute to improved diagnostic precision.     

Adductor spastic dysphonia: three years after recurrent laryngeal nerve resection

The voices of 33 patients, ages 44 to 79 years, were assessed after recurrent laryngeal nerve resection for adductor spastic dysphonia. Voice improvement was noted in all patients 24 hours after surgery: in 97% at 1 month, 97% at 6 months, 82% at 1 year, 70% at 1 1/2 years, 58% at 2 years, 52% at 2 1/2 years, and 36% at 3 years. Of the 64% with failed voices by 3 years, 48% were worse than before surgery. Of the 36% whose voices remained improved, 58% were worse than at any previous period and 42% were better. Failures among women (77%) were considerably higher than among men (36%). Except for one patient, none of the patients with improvement achieved a normal voice. Patients with improvement had varied types and degrees of dysphonia: breathiness, hoarseness, diplophonia, and falsetto pitch breaks. The voices of some patients approached normalcy. A high percent of patients had voice tremor and regular voice arrests on vowel prolongation, signaling that the spastic dysphonia may have been related to essential (voice) tremor and that the spastic dysphonia returned because of increased severity of the neurologic tremor. We conclude that recurrent laryngeal nerve surgery for adductor spastic dysphonia has long-term limitations and that the differential diagnosis between neurologic and psychogenic types is imperative prior to therapeutic decision making.     

Botulinum toxin management of adductor spasmodic dysphonia after failed recurrent laryngeal nerve section

This study examined botulinum toxin type A (BTX-A) treatment of adductor spasmodic dysphonia patients who had previously undergone recurrent laryngeal nerve section that failed to control symptoms. Information was retrieved from records of patients treated by our group between 1984 and 1999. Complete records with standardized outcome measurements were available for 181 BTX-A injection sessions in 16 patients who had had nerve section. These were compared to previously published information regarding 4,621 sessions in 639 adductor spasmodic dysphonia patients also treated by our group. Treatment with BTX-A resulted in significant improvement in voice function in the studied patients (change, 38.2% +/- 24.5%; p < .0001). The onset of effect took place approximately 2.3 days after treatment, and the peak effect about 10.0 days after treatment. The therapeutic effect lasted 14.1 weeks on the average. These features were not significantly different from those observed in adductor spasmodic dysphonia patients as a whole. The incidence of complications was also comparable. However, lower baseline and peak posttreatment perceptions of voice function in the nerve section group were statistically significant (baseline, 45.6% +/- 23.0% versus 52.4% +/- 22.0%; peak, 83.8% +/- 16.4% versus 89.7% +/- 13.0%; both p < .001). We conclude that BTX-A is effective in the treatment of adductor spasmodic dysphonia in patients who have had recurrent nerve section. However, nerve section may adversely affect perceived voice function and may make botulinum toxin therapy less satisfactory. Because of this finding, and because of the unusual pathological features of the focal dystonias, irreversible means of treating adductor spasmodic dysphonia should be approached with caution.     

Phonatory air flow characteristics of adductor spasmodic dysphonia and muscle tension dysphonia.

The purpose of this study was to determine if phonatory air flow characteristics differed among women with adductor spasmodic dysphonia (AdSD), muscle tension dysphonia (MTD), and normal phonation. Phonatory air flow signals were gathered during [pa] syllable repetitions. Mean phonatory air flow, coefficients of variation, and the presence of large air flow perturbations (75 ml/s or more) were examined for the three groups of speakers. There was no significant difference in mean phonatory air flow across groups, and very large intersubject variation in mean phonatory air flow occurred for both the AdSD and MTD groups. Coefficients of variation were similar for the groups of women with MTD and normal phonation but were significantly larger for the group with AdSD. Air flow perturbations were common with AdSD and rare with MTD. Relatively large coefficients of variation and air flow perturbations of at least 75 ml/s did occur for some women with normal voices who were 70 years of age or older. It appears that intrasubject variability in phonatory air flow may aid in the differentiation of AdSD and MTD when used in conjunction with other elements of a thorough voice evaluation. However, the potential contribution of aging to increased intrasubject variability in phonatory air flow must be considered when interpreting findings.     

Adductor spasmodic dysphonia and botulinum toxin treatment: the effect on well-being

Adductor spasmodic dysphonia (AdSD) is a controversial and enigmatic voice disorder. It is generally accepted that it has a neurologic, although undetermined, cause, and it is accompanied by much psychological and physical distress. In this prospective study, standardized psychometric tests were used to assess the personality characteristics and psychological and somatic well-being of 46 patients with AdSD. Moreover, the effect of botulinum toxin (Botox) treatment on their well-being was evaluated. No significant differences could be detected between patients and a representative norm group concerning 7 personality characteristics. Nevertheless, before treatment, there were significantly more psychological and somatic complaints. After establishment of a normal to near-normal voice with Botox injections, these complaints were reduced to normal levels--a finding suggesting these phenomena to be secondary to the voice disorder. These findings, and the normal personality characteristics, do not support a psychogenic cause of AdSD.     

Treatment of spastic dysphonia by recurrent laryngeal nerve section

The problem of management of patients with spastic dysphonia has been complicated by a general resistance to speech therapy, psychotherapy, hypnotherapy, and drug therapy. Dedo introduced the concept of recurrent laryngeal nerve section in an attempt to eliminate the hyperfunction and excessive adduction of the vocal folds. Eleven patients were treated by RLN section with satisfactory results in 8 and some improvement in the other 3. The operation was found to be generally uncomplicated and required on average 4 days of hospitalization. Dedo's theory that spastic dysphonia is caused by a neurotropic viral-induced proprioceptive nerve deficit represents a new search for organic cause. His most recent report of finding unmyelinated fibres in one-third of the resected recurrent laryngeal nerves is of questionable significance. The evidence of deep emotional conflict and/or compulsive lifestyle is found in the majority of the patients, but the syndrome is not typical of an hysterical or conversion neurosis. Regardless of etiologic theory, RLN section is an effective treatment in selected, longstanding, and resistant instances of spastic dysphonia.     

Spastic dysphonia: treatment by selective section of the recurrent laryngeal nerve

Selective section of the adductor branch of the recurrent laryngeal nerve appears to result in phonatory results similar to complete nerve section without the inherent morbidity. The abductor branch to the posterior cricoid-arytenoid muscle remains intact for glottic opening during inspiration. We emphasize the importance of careful preoperative patient evaluation as described by Dedo. All patients should be seen by a speech therapist and undergo a trial of speech therapy prior to surgical evaluation. A test block of the recurrent nerve with 1% xylocaine is imperative to allow the patient to hear the postoperative speech characteristics and give him a realistic expectation of the surgical result. We find that patients and referring professionals more readily accept the concept of selective nerve section.     

Intermediate results of 306 recurrent laryngeal nerve sections for spastic dysphonia

Recurrent laryngeal nerve section for spastic dysphonia was first performed in 1975 because prior forms of treatment had failed. Virtually every patient has had a detailed postoperative follow-up which includes a tape recording and a self-assessment questionnaire. The majority of patients remain free of spasticity at this medium-term follow-up. In some, spasticity recurred with less than preoperative severity, A small percentage of patients have a persistent breathy phonation. The first group is treated with vocal fold lateralization procedure using the CO₂ laser; the second, with Teflon.® When needed, voice therapy is also given. This paper provides a basis for diagnosis, indications for surgery, primary and secondary surgical techniques, encountered problems, and medium-term follow-up results.     

Implantation of a recurrent laryngeal nerve stimulator for the treatment of spastic dysphonia

Spastic dysphonia, a rare speech disorder, is characterized by strained phonation with excessively adducted vocal cords. Recurrent laryngeal nerve section, botulinum toxin injection into the vocalis-thyroarytenoid muscle complex, and other techniques have been used to treat this disorder. We have used percutaneous electrical stimulation of the recurrent laryngeal nerve with good results. Previous dog studies demonstrated the relative safety of an implantable recurrent laryngeal nerve stimulator. In this study, we directly stimulated the recurrent laryngeal nerve and vagus nerve in a dog without change in cardiorespiratory status. A Medtronic peripheral nerve stimulator was implanted in a patient with abductor spastic dysphonia. The cuff electrode was positioned around the recurrent laryngeal nerve and stimulation resulted in improvement in her voice. Extensive cardiopulmonary monitoring did not reveal any adverse response to stimulation and there was no discomfort to the patient. On the basis of the good results of this preliminary study, further study with long-term follow-up is under way.     

喉返神经损伤后喉肌病理生理研究

目的：通过对犬喉返神经损伤及再生过程中喉肌电生理及其病理变化进行研究,探讨喉返神经不同损伤形式的病理生理改变及转归特点。方法：实验用犬20只（40侧）分为喉返神经完全损伤组（全切法）、不完全损伤组（结扎法、挫灭法、半切法）及对照组,造模成功后的即刻、1、3、6和12个月观察甲杓肌和环杓后肌肌电特征及组织病理学改变。结果：造模后即刻全切法及结扎法肌电为电静息,挫灭法和半切法存在部分正常单个运动单位（MUP）及振幅减小的MUP混合肌电。神经损伤后1～3个月可出现纤颤电位,不完全损伤组3～6个月出现再生电位。全切法诱发电位基本无法引出,结扎法和半切法早期无诱发电位,后期可以引出振幅减小的诱发电位,结扎法小于半切法;而挫灭法始终都可以引出诱发电位,振幅与对照组无显著性差异,诱发电位潜伏期呈现先延长后缩短的趋势。随着全切、结扎、半切、挫灭损伤程度不同,肌纤维平均直径及肌束直径逐渐增大,单位面积细胞核数逐渐减少。结论：不同损伤,肌电特征及声带运动状态呈动态变化,喉返神经的损伤程度依次为完全损伤、不完全损伤（结扎法、半切法、挫灭法）,喉肌电图检查是声带麻痹诊断和评估的重要方法。     

甲状腺手术中喉返神经显露的意义

目的阐明甲状腺手术中显露喉返神经（recurrent laryngeal nerve,RLN）的优点。方法在452例不同类型的甲状腺手术中显露喉返神经,手术前后喉镜检查声带运动情况。结果共显露喉返神经748根,暂时性喉返神经损伤14例（占1．88％）,永久性损伤2例（占0．27％）。结论甲状腺手术中显露喉返神经可有效防止其损伤并有利于手术疗效。     

Modulation of nerve fibers in the rat thyroarytenoid muscle following recurrent laryngeal nerve injury

Conclusion. The present study suggested that a high level of thymidine phosphorylase (TP) gene expression is significantly associated with favorable prognosis of patients treated with 5-fluorouracil (5-FU)-based chemotherapy. Further studies consisting of large series should be performed to confirm our present results. Background. Expression levels of the thymidylate synthase (TS) and 5-FU metabolic enzymes including dihydropyrimidine dehydrogenase (DPD), TP, and orotate phosphoribosyl transferase (OPRT), are reported to be associated with sensitivity to 5-FU-based chemotherapy in several cancers. Patients and methods. Intratumoral mRNA expression levels of TS, DPD, TP, and OPRT in pretreatment biopsy specimens were quantified in 27 patients with advanced oropharyngeal squamous cell carcinomas. Association of these expression levels with response to platinum and 5-FU-based chemotherapy and survival were analyzed statistically. Results. By Spearman's correlation analysis, significant correlation was observed between TS and TP (γ=0.51, p=0.018). While no correlation was observed between the tumor regression and expression of any of the genes investigated, significant association was observed between prognosis and mRNA expression levels of TS and TP. Multivariate Cox regression analysis revealed that TP mRNA expression level is a significant factor predicting prognosis (hazard ratio (HR) = ? 0.204, p=0.043).     

Variability in nerve patterns of the adductor muscle group supplied by the recurrent laryngeal nerve

INTRODUCTION: Accurate knowledge of the nerve supply of each individual muscle is needed to achieve a successful selective reinnervation of the larynx. The aim of the present work was to study the nerve supply of the adductor laryngeal muscles supplied by the recurrent laryngeal nerve. STUDY DESIGN: Morphologic study of human larynges. METHODS: The muscular nerve supply was studied in a total sample of 75 human larynges obtained from necropsies (47 males and 28 females, age range from 41-95 years) and examined by careful dissection using a surgical microscope. RESULTS: The arytenoid muscle received one branch from each recurrent nerve. In 88% of cases, this branch arose in a common trunk with the upper branch of the posterior cricoarytenoid muscle. In 8% of cases, the nerve for the arytenoid muscle also had a branch going to the lateral cricoarytenoid muscle. The arytenoid muscle also received from one to three pairs of branches from the posterior division of the internal laryngeal nerve; these were interconnected ipsi- and contralaterally and were also connected to the two branches coming from the recurrent laryngeal nerve. The lateral cricoarytenoid muscle received from one to six branches from the recurrent nerve, but in 5.8% of cases, it also received a twig from a connecting branch between the recurrent nerve and the external (5.6%) or the internal laryngeal nerves (0.2%). The thyroarytenoid muscle received from one to four branches from the recurrent nerve, but in 5.6% of cases, it also received a twig from a connecting branch between the recurrent nerve with the external (4.6%) or the internal (1%) laryngeal nerves. CONCLUSION: No abductor or adductor division of the recurrent laryngeal nerve was found in the present study. In 88% of cases, the nerve supply to the arytenoid muscle (adductor) and the posterior cricoarytenoid muscle (abductor) arose from a common trunk, which in 8% of cases, also had a branch to the lateral cricoarytenoid muscle. Furthermore, the high incidence of branches innervating the adductor muscles from connections between the recurrent laryngeal nerve and the internal and external laryngeal nerves led us to reconsider the contribution of these nerves in the supply to this muscle group.     

Repair of the recurrent laryngeal nerve

Surgical repair and reconstruction of the injured recurrent laryngeal nerve are discussed. Tips to avoid inadvertent nerve injury are noted, as are aspects of non-recurring recurrent laryngeal nerves. The controversy regarding recurrent laryngeal nerve anastomosis is updated, and a protocol for management of the injured recurrent laryngeal nerve is presented.