Recurrent Nerve/Ansa Cervicalis Nerve Anastomosis: A Treatment Alternative in Unilateral Recurrent Nerve Paralysis

Sectioning of the right recurrent nerve was done in 5 mongrel dogs under general anaesthesia. The distal stump was anastomosed with the ansa cervicalis nerve branch to the sternothyroid muscle. Three to 5 months later the vocal cord movements during light and very light anaesthesia were videorecorded. Under light anaesthesia contraction and medial bulging of the reinnervated right vocal cord occurred in 4 of the dogs. Under very light anaesthesia there was also some adduction of the right vocal cord in these 4 dogs. The right recurrent nerve was then sectioned proximally to the anastomosis and stimulated electrically. In all 5 dogs we observed that electrical stimulation produced a strong adduction of the right vocal cord. Histochemistry of the right vocal and posterior cricoarytenoid muscles showed that reinnervation had taken place. The study indicates that in cases of unilateral vocal cord paralysis an anastomosis between the ansa cervicalis and the recurrent nerve will result in improved phonatory function of the affected vocal cord.     

Recurrent nerve/ansa cervicalis nerve anastomosis: a treatment alternative in unilateral recurrent nerve paralysis.

Sectioning of the right recurrent nerve was done in 5 mongrel dogs under general anaesthesia. The distal stump was anastomosed with the ansa cervicalis nerve branch to the sternothyroid muscle. Three to 5 months later the vocal cord movements during light and very light anaesthesia were videorecorded. Under light anaesthesia contraction and medial bulging of the reinnervated right vocal cord occurred in 4 of the dogs. Under very light anaesthesia there was also some adduction of the right vocal cord in these 4 dogs. The right recurrent nerve was then sectioned proximally to the anastomosis and stimulated electrically. In all 5 dogs we observed that electrical stimulation produced a strong adduction of the right vocal cord. Histochemistry of the right vocal and posterior cricoarytenoid muscles showed that reinnervation had taken place. The study indicates that in cases of unilateral vocal cord paralysis an anastomosis between the ansa cervalalis and the recurrent nerve will result in improved phonatory function of the affected vocal cord.     

Restoration of physiologic vocal fold abduction with the ansa cervicalis nerve

An attempt was made to restore physiologic abduction of the vocal fold using the ansa cervicalis nerve. In adult dogs, the ansa cervicalis nerve was anastomosed to the abductor branch of the recurrent laryngeal nerve. In the four surviving dogs, abduction of approximately 50% to 70% of normal was restored synchronous with inspiration. This technique seems to work almost as well as the phrenic nerve and is easier to perform.     

神经肌蒂移植同时恢复麻痹声带内收及外展功能的实验研究

目的 探索一种能同时恢复麻痹声带内收及外展功能的治疗方法。方法 对狗一侧喉返神经及喉上神经运动支联合麻痹的喉内肌,采用颈袢胸骨甲状肌肌蒂移植于麻痹环杓后肌,颈袢甲状舌骨肌肌蒂移植于麻痹侧环杓侧肌作为实验组,并仅用颈袢胸骨甲状肌肌蒂移植于麻痹侧环杓后肌作为对照组。术前及术后４个月行声带录像、喉肌电图检测、组织学检查。结果术后４个月所有动物均不同程度地恢复了麻痹声带的生物功能。实验组术侧声带内运动明显     

Functional results after experimental reinnervation of the posterior cricoarytenoid muscle in dogs

The purpose of the present investigation was to test and compare three different types of experimental posterior cricoarytenoid (PCA) muscle reinnervation. Dogs were subjected to reinnervation by the recurrent nerve itself (self-reinnervation) (n = 6), by the ansa cervicalis nerve (n = 5) or by the phrenic nerve (n = 5). In all but three of the self-reinnervation cases the adductor branch of the nerve was cut and ligated. Three to seven months postoperatively--depending upon the experimental approach--the animals were anesthetized and the function of the vocal cords was tested, visually evaluated and photographed. In the self--reinnervated larynges there were no observable movements on the reinnervated side during quiet inspiration, while during forced inspiration there were small but inconsistent movements. In the larynges reinnervated by the ansa cervicalis nerve no movements could be observed on the reinnervated side during either quiet or forced respiration. In four out of five larynges reinnervated by the phrenic nerve there were larger excursions on the reinnervated side as compared to the normal side during quiet respiration. During forced inspiration the excursions increased on both sides, but relatively more on the normal side. In all experiments indirect electrical stimulation gave large excursions on the experimental side indicating successful reinnervation. It is concluded that the phrenic nerve appears to be the best alternative if reinnervation of the PCA muscle in paralyzed larynges is attempted.     

Study on contractile properties of the posterior cricoarytenoid muscle after delayed reinnervation]

To study date on the contractile properties of posterior cricoarytenoid muscle after delayed reinnervation of different reinnervated methods. Twenty four dogs were reinnervated at 0,4,5,6,10 and 12 month interval following recurrent laryngeal nerve via the phrenic nerve anastomosed to the recurrent laryngeal nerve after cutting the adductor branch and ansa cervicalis-sternothyroid muscle pedicle implanted into the posterior cricoarytenoid muscle. After 6 months, a series of contractions were recorded from each side in twenty living dogs. The results showed that contractile force of reinnervated muscle decreased gradually with the time of denervation, but contractile force of muscle was no significantly difference between reinnervated side of nerve anastomosed group in 4 months after denervated and normal side, and it was significantly difference between nerve anastomosed group and nerve-muscle pedicle implanted group at some time of delayed reinnervation. The contractile time of reinnervated side of two operated groups was similar to that of normal side. The conclusion demonstrated that the contractile properties can indicate exactly reinnervated degree of muscle, and the earlier reinnervation was performed, the better curative effect was.     

环杓后肌延期神经再支配后收缩特性的定量分析

为观察延期神经再支配环杓后肌的收缩特性，比较不同神经再支配方法的疗效，我们选择２４只犬，在右喉返神经切断后，于即刻，４，６，８，１０和１２个月时，分别以２只犬行选择性膈神经与喉返神经吻合（切断内收肌支）支配右环杓后肌（神经吻合组）；另１２只犬分别以２只行颈袢胸骨甲状肌蒂植入右环杓后肌（神经植入组）。组后饲养６个月，测定环杓后肌收缩强度及时间。结果表明，两组术侧的环杓后肌收缩力恢复率随病程延长而下降     

不同延期神经再支配环杓后肌方法的疗效观察

目的：探讨环杓后肌延期神经再支配的方法及时机。方法：将２９只狗分成三组，两个实验组在喉返神经切断后即刻、４、６、８、１０、１２个月分别将膈神经与喉返神经吻合选择性支配环杓后肌和颈袢神经—胸骨甲状肌蒂植入环杓后肌，对照组喉返神经切断后各时间不作任何手术。结果：两个实验组６个月后行喉镜、神经肌电及肌收缩力、组织化学证实：神经吻合组各时间效果明显好于神经肌蒂植入组，但两种术式疗效均随病程延长而下降。结论：神经吻合法延期神经再支配环杓后肌６个月内效果较好，而神经肌蒂植入法治疗环杓后肌麻痹最好不晚于失神经后４个月，否则效果不佳     

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.     

神经肌蒂移植术治疗声带麻痹的对比实验研究

目的;比较不同神经肌蒂环榴后肌移植术治疗声带麻痹的疗效,为临床选择术式提供参考。方法：建立联合性喉麻痹模型。分别用颈袢胸骨舌骨肌肌蒂（简称颈袢组）和副神经胸锁乳突肌肌蒂（简称副神经组）移植于环杓后肌,以恢复声外展功能,术后４个月,分别进行录音,直达喉镜和电视喉动态镜观察声带运动并录像,喉肌电图检查,环榴后肌透射电子显射镜检查和酶组织化学检查,并进行电脑图像定量分析。结果：术后颈袢组和副神经组犬吠声     

颈袢亚分支植入术治疗单侧喉麻痹的实验研究

用１１只狗，分成实验组（７只）及对照组（４只），均切断左侧喉返神经和左侧喉上神经外支造成单侧喉麻痹。实验组将颈拌（舌下神经拌）主支的各亚分支植入声带内收肌中，对照组不作此神经修复术。６个月后行喉镜检查、喉肌电图检查、肌收缩力测定、组织化学检查及运动终板细胞化学电镜观察，证实实验组声带内收肌获得有效的再神经支配，声带内收为预计亚分支再神经支配的结果，未见吸气性声带内收现象。对照组声带内收肌无再神经支配征象。     

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.     

A histochemical evaluation of experimentally reinnervated canine laryngeal muscles

Sixteen dogs underwent different types of experimental reinnervation procedures of the posterior cricoarytenoid (PCA) muscle - reinnervation by the recurrent nerve itself (self-reinnervation) (n = 6), by the ansa cervicalis nerve (n = 5) or by the phrenic nerve (n = 5). After functional evaluation the normal left and the reinnervated right PCA muscles were removed for histochemical analysis. Cryostat sections were incubated for actomyosin ATPase, NADH-TR and alpha-GPDH. All muscles showed microscopical evidence of successful reinnervation. There was a slight change in the muscle fiber type composition in the reinnervated muscle as compared to the normal side. Incubations for the NADH-TR and alpha-GPDH showed less staining intensity in the reinnervated muscles. The histochemical differences between normal and reinnervated muscles were small, however, and probably of minor importance with regard to the function of the muscles.     

Hypoglossal nerve transfer for laryngeal reinnervation: a preliminary study

The hypoglossal nerve is a logical donor nerve for hemilaryngeal reinnervation because 1) its activity coincides with normal laryngeal adduction during speech and deglutition; 2) it is a large nerve with many axons; and 3) donor site morbidity is low. This method of laryngeal reinnervation has not been previously reported. Previous studies using the ansa cervicalis for reinnervation have failed to show spontaneous activity. Hypoglossal-to-recurrent laryngeal nerve anastomosis was performed on a series of 5 dogs. The vocal folds were viewed monthly, with the animals awake, by infraglottic examination through a permanent tracheostomy. One dog failed due to technical error. The remaining 4 dogs began to exhibit spontaneous vocal fold adduction within 2 to 4 months. Vocal fold motion was synchronous with spontaneous tongue motion. Complete glottic closure was seen during swallowing at 3 to 5 months. Intraglottic pressure measurements following reinnervation were normal. Hypoglossal nerve transfer appears to be capable of providing functional adduction to the paralyzed hemilarynx. The potential advantages and disadvantages of this new technique are discussed.     

家犬双侧环杓后肌失神经及颈袢神经再支配后肌卫星细胞活性变化

目的 探讨家犬双侧环杓后肌失神经支配及用颈袢神经再吻合支配后肌卫星细胞活性的变化.方法 随机数字表法将24只家犬分成3组,每组8只,分别为切断双侧喉返神经组,切断喉返神经后即刻颈袢神经再吻合组,不切断喉返神经的对照组.3组动物手术后再饲养9周后再次暴露喉返神经及环杓后肌,使用喉返神经诱发环杓后肌电位来验证喉返神经的再通情况;双盲法提取环杓后肌肌肉组织中总RNA,反转录后做实时定量聚合酶链反应(PCR)检测肌卫星细胞增殖分化标记物Myogenin、Myf5和Pax7的mRNA表达.结果 手术后3组动物各有1只死亡或感染退出实验.术后9周诱发神经环杓后肌肌电图提示对照组动物喉返神经功能均正常,切断组7只动物电刺激都没有反应,吻合组均有神经再通.Myogenin的mRNA相对表达量切断组较对照组和吻合组均有明显升高(Z值为1.42和1.38,P值均＜0.05),Myf5的mRNA表达切断组也明显高于对照组和吻合组(Z值为1.66和1.69,P值均＜0.01);切断组Pax7的mRNA表达明显高于对照组(Z=1.66,P＜0.01),也高于吻合组(Z=1.42,P＜0.05);而吻合组与对照组Myogenin、Myf5和Pax7的mRNA表达差异均无统计学意义(P值均＞0.05).结论 双侧喉返神经切断后,环杓后肌的肌卫星细胞增殖分化的mRNA表达增强,而同颈袢神经再吻合后肌卫星细胞的增殖分化表达下降.

Abstract：

Objective To investigate the activity of bilateral posterior cricoarytenoid muscle satellite cell after denervation or reinnervation with ansa cervicalis. Methods Twenty four dogs were randomly divided into 3 groups. The bilateral laryngeal recurrent nerves were cut in group one in all dogs. The bilateral laryngeal recurrent nerves were anastomosed with ansa cervicalis after incision in group two in all dogs. The dogs in group three were used as control. Nine weeks after surgery, the electromyography was used to test the regeneration of the nerve. The posterior cricoarytenoid muscles biopsy were collected. The expression of mRNA of Myogenin, Myf5, and Pax7 was assayed by realtime RT-PCR after total RNA isolation. Results Two dogs died after surgery in incision and anastomose group. The electromyography suggested that the RLN of all dogs had denervated in the incision group and had reinnervated in the anastomose group after 9 weeks. Myogenin mRNA from RLN incision dogs PCA muscles had greater expression versus controls ( Z = 1.42, P ＜ 0. 01 ) or anastomosed dogs ( Z = 1.38, P ＜ 0. 01 ). Myf5 mRNA expression from RLN incision dogs PCA muscles had significant increase versus control dogs ( Z = 1.66, P ＜0. 01 ) or anastomosed dogs ( Z = 1.69, P ＜ 0. 01 ). Pax7 mRNA expression from RNL incision dogs had significant increase compared with control ( Z = 1.66, P ＜0. 01 ) or anastomosed animals ( Z = 1.42, P ＜0. 05 ). There was no significant difference in Myogenin ( Z = 1.34, P ＞ 0. 05 ), Myf5 ( Z = 0. 54, P ＞0. 05) and Pax ( Z = 0. 54, P ＞ 0. 05 ) mRNA expression between controls and anastomosed animals.Conclusions The bilateral denervation of RLN cause significantly increasing in dog PCA muscle satellite cell proliferation and differentiation. The bilateral reinnervation of RLN cause PCA muscle satellite cell come back nonproliferative, quiescent state in dog.     

颈袢主支吻合术治疗单侧声带麻痹的临床观察

采用颈袢主支与喉返神经内收肌支吻合术治疗单侧声带麻痹７例。结果表明，声音恢复满意，术后声学三参数频率微扰、振幅微扰及标化嗓音能量均明显减小，平均值均在正常范围之内；喉镜检查发现术侧声带均有不同程度的内移，其中３例恢复至正中位；喉肌电图显示，发育及喉括约活动时术侧喉内收肌恢复与健侧基本同步的密集型强放电，证明术侧喉内收肌获得颈袢主支有效的神经再支配。提示该术是治疗单侧声带麻痹一种理想方法。     

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.     

Update: Ansa Cervicalis to Recurrent Laryngeal Nerve Anastomosis for Unilateral Laryngeal Paralysis

Twenty cases of unilateral laryngeal paralysis are reported. Satisfactory follow-up intervals and data (videostroboscopy and glottographic analysis) were available on 12 patients. The excellent to normal phonatory quality achieved in many of these patients indicates that the ansa cervicalis to recurrent laryngeal nerve anastomosis is the procedure of choice in selected patients with unilateral vocal cord paralysis. Excellent medialization of the paralyzed cord, as well as correction of arytenoid malposition and thyroarytenoid muscle atrophy appear to explain the technique's success, since the reinnervated cord neither abducts nor adducts. We feel that this technique is the procedure of choice in younger patients, or those who use their voices professionally, since the phonatory quality achieved is superior to Teflon® injection or Isshiki thyroplasty, and the technique is reversible.     

Update: Laryngeal Reinnervation for Unilateral Vocal Cord Paralysis With the Ansa Cervicalis

Eight patients underwent ansa cervicalis anastomosis to the adductor branch of the recurrent laryngeal nerve for unilateral vocal cord paralysis. They were followed long enough (at least 1 year) to determine if the procedure was successful. All cases have been subjected to preoperative and postoperative voice recording, acoustic analysis, and videolaryngoscopy. Some of them have been subjected to stroboscopy and electromyography (EMG). Data from these cases indicate that satisfactory phonatory quality may be achieved after the procedure. The reinnervated vocal cord neither abducted nor adducted, but it presented itself in midline for precise apposition with the normal cord. Synchronous mucosal waves in both vocal cords could be observed. EMG showed that the procedure produced satisfactory reinnervation of the adductory muscles. Therefore, the authors believe that the procedure could be proposed as an alternative to Teflon injection or thyroplasty in selected cases.     

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.