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。     

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.     

失神经支配对人喉内收肌和外展肌肌纤维形态的影响

目的:探讨失喉返神经支配对人喉内收肌和外展肌肌纤维形态学的影响规律,为临床晚期喉返神经修复的可行性提供实验依据。方法:内收肌取自环杓侧肌,外展肌取自环杓后肌,人正常环杓侧肌和环杓后肌作为正常对照组(各7例),失神经支配组按喉返神经损伤的不同时限分组:38例环杓后肌中,0.5～1年组7例,>1～2年组10例,>2～3年组8例,>3～6年组8例,>6年组5例;29例环杓侧肌中,0.5～1年组7例,>1～2年组6例,>2～3年组6例,>3～6年组6例,>6年组4例。分别采用苏木精-伊红染色、Masson三色染色,图像分析系统定量分析失喉返神经支配后喉内收肌和外展肌肌纤维截面积和胶原结缔组织截面积的变化。结果:随着失神经时限的延长,肌纤维的截面积逐渐缩小,而胶原纤维截面积逐渐增加。①环杓侧肌失神经0.5～1年组、>1～2年组、>2～3年组间比较差异无统计学意义(P>0.05),失神经>3～6年组肌肉/胶原截面积比下降最为明显,与失神经>2～3年组差异有统计学意义(P<0.05);②环杓后肌正常对照组与失神经0.5～1年组、>1～2年组、>2～3年组、>3～6年组间两两比较,差异均有统计学意义(P<0.05);③环杓侧...     

Intraoperative neuromonitoring by vagus nerve stimulation in thyroid surgery: Clinical assessment of recurrent and superior laryngeal nerves

Intraoperative neuromonitoring of the laryngeal nerves during thyroidectomy is a reliable method to assess nerve function. After identification of the cricothyroid ligament, a bipolar electrode is selectively inserted through the ligament into the thyroarytenoid muscle (TAM) and cricothyroid muscle (CTM). Vagus nerve stimulation then allows precise monitoring of the recurrent laryngeal nerve and the external branch of the superior laryngeal nerve (EBSLN) in the TAM and CTM, respectively. A significant muscle response (greater than 100 μV) is 100% predictive of preserved laryngeal mobility, while the absence of a muscle response is 70% predictive of vocal fold paralysis with 100% sensitivity and 98% specificity. A significant thyroarytenoid muscle response is only recorded ipsilateral to the stimulation with a shorter latency on the right side. A concomitant TAM and CTM response to vagus nerve stimulation or EBSLN stimulation is observed in more than 70% of cases.     

显露喉返神经在甲状腺手术中的意义

目的:探讨显露喉返神经在甲状腺手术中的意义。方法:回顾性分析我科收治的共332例甲状腺手术患者的资料,全部患者均在全身麻醉下进行,术中均解剖术侧喉返神经。单侧腺叶切除131例,双侧次全切除138例,单侧腺叶切除加对侧腺叶次全切除51例,双侧甲状腺全切术12例。结果:手术过程中共533条喉返神经主干均得到很好的显露,术后共4例(0.75%)出现声嘶,无麻醉插管引起,均为单侧声带固定,行激素、营养神经药物等治疗,均在3个月内恢复,无永久性损伤。结论:在行甲状腺手术时,结合运用多种解剖喉返神经的方法,能够有效避免喉返神经的损伤。     

困难甲状腺手术中喉返神经解剖的研究

目的：探讨困难甲状腺手术中喉返神经解剖的方法,以最大限度减少损伤,提高手术的安全性。方法：回顾性分析52例巨大结节性甲状腺肿、胸骨后结节性甲状腺肿、位于甲状腺下极的结节性甲状腺肿、甲状腺癌以及甲状旁腺肿瘤等困难甲状腺手术中喉返神经的解剖过程和方法,了解病变累及喉返神经的状况以及避免喉返神经损伤的措施。结果：52例患者中,除2例甲状腺癌一侧喉返神经受侵予以切除外,其余50例喉返神经均解剖成功。50例喉返神经解剖成功者中,3例喉返神经拉长者术后无声嘶,2例喉返神经局部压为扁平者术后也无声嘶,3例术后轻微声嘶者经营养神经治疗1~3个月后恢复正常。1例喉不返神经,2例胸骨劈开,2例术后行气管切开。术后无并发症发生。结论：困难甲状腺手术中喉返神经的解剖大多需要游离腺叶和肿瘤并将其翻向内前上方,再以气管食管沟、甲状腺下动脉和（或）甲状软骨下角为标志进行解剖,实践证明该方法可行。     

Modulation of myosin heavy chains in rat laryngeal muscle

OBJECTIVES: To test the hypothesis that myosin heavy chain (MHC) composition is a biological marker indicative of appropriate and functional reinnervation. STUDY DESIGN: Age-matched adult rats were randomized for prospective study under three experimental conditions. METHODS: In adult rats, three experimental conditions were surgically created, including transient recurrent laryngeal nerve (RLN) crush injury, RLN transection and repair, and cricoarytenoid joint fixation with intact RLN. Animals were survived for 30, 90, and 180 days. At each interval, vocal fold mobility was assessed by rigid microlaryngoscopy. Laryngeal electromyography (EMG) was performed before euthanasia. The thyroarytenoid and posterior cricoarytenoid muscles were then excised, each muscle was processed for sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and MHC composition was determined. RESULTS: Thirty days after nerve crush injury, three of six animals regained vocal fold mobility and normal MHC composition. Impaired vocal fold motion in three of six animals was associated with MHC composition characteristic of denervation. At 90 and 180 days, normal vocal fold motion and normal MHC composition were observed in all animals. Following nerve transection and repair, impaired vocal fold motion and MHC composition characteristic of denervation were observed in all animals, despite evidence of reinnervation on EMG. Following joint fixation, alteration in MHC composition consistent with denervation was observed only at 30 days, as was evident in the nerve crush model. CONCLUSION: Temporary injury and vocal fold immobilization result in transient shifts in MHC composition. Nerve transection and repair result in persistent alteration of MHC composition and vocal fold dysfunction. The expression of normal MHC composition is dependent on the condition of appropriate neural contact and functional reinnervation.