Recurrent Laryngeal Nerve Identification and Assessment during Thyroid Surgery: Laryngeal Palpation

Electrical identification and monitoring of the recurrent laryngeal nerve (RLN) has been proposed as an adjunct to standard visual identification of the nerve during thyroid and parathyroid surgery. This study was undertaken to assess laryngeal palpation as an intraoperative technique for identifying and assessing the RLN during surgery and to investigate the relation between laryngeal palpation and associated laryngeal electromyographic (EMG) activity. The postcricoid region of the larynx during surgery was palpated through the posterior hypopharyngeal wall to sense posterior cricoarytenoid muscle contraction in response to ipsilateral RLN stimulation (i.e., the laryngeal twitch response.) Laryngeal palpation was performed in a series of 449 consecutive thyroid and parathyroid surgeries with 586 RLNs at risk. All patients underwent preoperative and postoperative laryngoscopy to assess vocal cord mobility. In a subset of patients, laryngeal palpation and simultaneous laryngeal EMG recordings were compared during intraoperative RLN stimulation. In this series, there was no permanent RLN paralysis. There was one case of temporary RLN paralysis secondary to neural stretch that resolved 6 weeks postoperatively (temporary paralysis rate: 0.2% of patients, 0.2% of nerves at risk). Intraoperative laryngeal palpation of the laryngeal twitch response reliably correlated with normal postoperative vocal cord function. Loss of the laryngeal twitch response occurred in the single case of temporary paralysis in the setting of an anatomically intact nerve. Laryngeal palpation correlated well with simultaneous laryngeal EMG activity. There were no palpation-induced laryngeal injuries or laryngeal edema. There were also no RLN injuries due to repetitive neural stimulation. Intraoperative laryngeal palpation during RLN stimulation is a safe, reliable method for neural monitoring that can assist in RLN identification and assessment during thyroid and parathyroid surgery. Most importantly, it provides important prognostic information regarding ipsilateral vocal cord function at the completion of the initial side of the thyroid or parathyroid surgery. Intraoperative laryngeal palpation allows the surgeon to stage contralateral surgery if RLN damage is diagnosed, thereby avoiding the potential for bilateral vocal cord paralysis. We believe that laryngeal palpation is useful as an adjunct to formal EMG monitoring during thyroid and parathyroid surgery.     

The laryngeal mask airway for thyroid and parathyroid surgery

The role of the laryngeal mask airway for thyroid and parathyroid surgery was studied in 97 consecutive patients. In 50% the technique combined electrical stimulation of the recurrent laryngeal nerve with visualisation of vocal cord movement via a fibreoptic bronchoscope. Stimulation was required in 10% to assist in identifying recurrent laryngeal nerve position during difficult surgical dissection. In the remaining 40% stimulation was used to confirm nerve integrity and for teaching purposes. Tracheal intubation was required for seven patients but in only two of these was intubation unplanned. The incidence of postoperative recurrent laryngeal nerve dysfunction was zero. These data suggest that the technique offers a safe alternative in airway management and may provide advantages in terms of preservation of recurrent laryngeal nerve function.     

Sensitivity and Specificity of Intraoperative Recurrent Laryngeal Nerve Stimulation Test for Predicting Vocal Cord Palsy after Thyroid Surgery

INTRODUCTION Recurrent laryngeal nerve (RLN) palsy after thyroidectomy, although infrequently encountered, can decrease quality of life. In addition to the hoarseness that occurs with unilateral RLN palsy, bilateral RLN palsy leads to dyspnea and often to life-threatening glottal obstruction. Therefore, intraoperative awareness of the nerve’s status is of great importance. This study examined the sensitivity and specificity of a palpation technique to detect contraction of the posterior cricoarytenoid muscle (PCA) through the posterior hypopharyngeal wall while the RLN was being stimulated with a disposable nerve stimulator during thyroid surgery (the laryngeal palpation test) to predict postoperative RLN deficits. Methods A total of 2197 RLNs in 1376 patients were identified to be at risk of injury during thyroidectomy performed between July 2003 and August 2004. Postoperative RLN integrity was assessed using direct laryngoscopy or laryngofiberoscopy to visualize vocal fold mobility. Results Altogether, 76 RLNs failed to elicit a PCA contraction in response to nerve stimulation, and 80 cases of temporary vocal cord palsy and 21 cases of permanent vocal cord palsy were recognized on postoperative evaluation. For postoperative vocal cord palsy, the sensitivity and specificity of the laryngeal palpation test were 69.3% and 99.7%, respectively, with a positive predictive value of 92.1% and negative predictive value of 98.5%. For permanent vocal cord palsy, the sensitivity and specificity were 85.7% and 97.3%, respectively, with a positive predictive value of 23.7% and negative predictive value of 99.8%. Conclusions The laryngeal palpation test is not a particularly useful method for predicting the level of RLN function after thyroidectomy. All patients must be examined postoperatively by direct laryngoscopy or laryngofiberoscopy to check vocal cord mobility. Even if there is no contraction of the PCA and we detect vocal cord palsy immediately after surgery, vocal cord palsy often recovers within 1 year when visual preservation of RLN is successful.     

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喉返神经损伤引起的声带麻痹是甲状腺手术常见的严重并发症之一,以单侧多见,造成不同程度的声音嘶哑、误吸和呛咳等症状,影响病人的生活质量。传统的治疗方法如声带注射术、甲状软骨成形术和杓状软骨内收术等虽能改善发音,但这种声音缺乏音调、音量的调节功能,且远期疗效不满意。声带麻痹的最佳治疗方法是通过神经修复手术恢复麻痹喉的生理性功能。手术方法包括:喉返神经探查减压术、喉返神经端端吻合术、颈袢喉返神经吻合术、游离神经移植术、神经肌蒂埋植术或神经植入术、舌下神经转位术及喉神经修复联合声带内移术等。早期减压效果最佳,颈袢喉返神经吻合等神经修复术也能有效地恢复喉的发音功能。损伤病程长者宜采用神经修复联合声带内移手术。喉神经修复术式的选择应根据病程、神经损伤的部位、程度、类型而定。     

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??Techniques and tips in reinnervation surgery for unilateral recurrent laryngeal nerve injury in thyroid surgery LI Meng, ZHENG Hong-liang.Department of Otolaryngology Head & Neck Surgery, Changhai Hospital, Navy Medical University, Shanghai 200433, China
Corresponding author??ZHENG Hong-liang??E-mail??zheng_hl2004@163.com
Abstract Unilateral vocal cord paralysis caused by injury to unilateral recurrent laryngeal nerve (RLN) injury is one of the most common and serious complications of thyroid surgery. Main manifestations include varying degrees of hoarseness??coughing??and aspiration??which greatly affect patients’ quality of life.The best treatment for vocal cord paralysis is reinnervation of the laryngeal muscles so as to recover the physiological function of the paralyzed larynx??which consists of nerve exploration and decompression??end to end anastomosis of RLN??ansa cervicalis to RLN anastomosis??free nerve graft transfer??reinnervation surgery combined with medialization of vocal cord. Among which ansa cervicalis to RLN anastomosis might be the most optimal option for the patients. Surgical indications should be strictly controlled and some surgical techniques and tips should be followed, which will be introduced in the present study.     

喉肌电活动实时监测喉返神经在再次甲状腺手术中的应用

目的探讨实时监测技术对预防喉返神经损伤的意义及应用价值。方法对55例再次甲状腺手术患者在全麻手术中使用喉返神经探测仪进行实时喉返神经监测（IONM）,术中分离显露喉返神经,并以神经刺激探针探测证实喉返神经在甲状腺后段行程及功能状态以保护其免受损伤,评估患者术后喉返神经损伤和声带功能恢复情况。结果共探测喉返神经107条,均成功显露。4例术前已证实有单侧声带麻痹的患者,术中探查该侧喉返神经证实3例被离断,另有1例被结扎,经松解后喉返神经肌电信号恢复,术后声带功能恢复。2例（3.64%）完整显露喉返神经的病例,手术结束前肌电信号消失,术后出现暂时性声带麻痹,均于2个月内恢复。结论使用喉返神经探测仪利于显露和保护喉返神经,有助于发现导致喉返神经损伤的原因并能较好地预测术后声带功能恢复的情况,减少医源性喉返神经损伤发生率,值得在再次甲状腺手术中推广。     

Use of the laryngeal mask airway in thyroid and parathyroid surgery as an aid to the identification and preservation of the recurrent laryngeal nerves.

A prospective study was carried out in patients undergoing thyroid and parathyroid surgery using a laryngeal mask airway (LMA) and electrical nerve stimulation to identify the recurrent laryngeal nerves. A total of 150 consecutive patients undergoing thyroid and parathyroid surgery by a single surgeon were assessed for suitability of anaesthesia via the LMA. Peroperatively, a fibre-optic laryngoscope was passed through the LMA to enable the anaesthetist to visualise the vocal cords while adduction of the cords was elicited by applying a nerve stimulator in the operative field. In all, 144 patients were selected for anaesthesia via the LMA. Fibre-optic laryngoscopy and nerve stimulation were performed in 64 patients (42.7%). The trachea was deviated in 51 (34.0%) and narrowed in 33 (22.0%). The recurrent laryngeal nerves were identified in all patients. There were no cases of vocal cord dysfunction resulting from surgery. The LMA can be safely used for thyroid and parathyroid surgery even in the presence of a deviated or narrowed trachea. It can assist in identification and preservation of the recurrent laryngeal nerve and is, therefore, of benefit to both patient and surgeon.     

Intraoperative electrophysiological monitoring of the recurrent laryngeal nerve in thyroid gland surgery--a prospective study

INTRODUCTION: In the last few years the use of intraoperative electrophysiological monitoring of the recurrent laryngeal nerve (RLN) in thyroid gland surgery has become more and more important. PATIENTS AND METHOD: In a prospective study 223 nerves at risk in 116 patients were monitored with the Neurosign(R)100 (Fa. Magstim Ltd., UK). We used intramuscular needle electrodes inserted into the vocal muscle through the conic ligament. Practicability, complications, acceptance and predictive value of the method were documented. Recurrent nerve palsy rate and complications were compared with a control group operated upon without monitoring. RESULTS: The intraoperative delay using this method was on average 8.9 minutes. There were problems with monitoring equipment avoiding use in 6.4 %. In 2 cases (1.7 %) an accidental lesion of endotracheal tube cuff was found related to malpositioning of the needle and in 7.7 % a hematoma of the vocal cords was observed. 73.3 % of the surgeons accepted the method to identify and control the nerve integrity. False-positive and false-negative signals may occur. In cases of a final real stimulus response a regular vocal cord motility was found in 95 %. If a nerve conduction block was noted an immobility of ipsilateral vocal cord was diagnosed postoperatively in 50 %. There was no decrease in transient recurrent palsy rate using monitoring (10.7 % vs. 9.6 % without monitoring) but in permanent paralysis (1.8 % vs. 3.0 %). CONCLUSIONS: It may be concluded that intraoperative electrophysiological monitoring of the RLN is a simple and accepted method with low complications reducing the incidence of permanent RLN palsy rate. We found the monitoring especially useful for operations of recurrent goiter and carcinomas of the thyroid gland as well as for learning thyroid gland surgery.     

甲状腺手术中喉返神经损伤修复术要点与技巧

喉返神经损伤引起的声带麻痹是甲状腺手术常见的严重并发症之一,以单侧多见。单侧声带麻痹的主要症状为不同程度的声音嘶哑、误吸和呛咳等,严重影响病人的生活质量。目前单侧声带麻痹最理想的治疗方式为喉返神经修复手术,方法包括喉返神经探查减压术、喉返神经端端吻合术、颈袢喉返神经吻合术、游离神经移植术、神经肌蒂埋植或神经植入术等。其中,以颈袢-喉返神经吻合术效果最佳。若能把握好手术适应证且遵循一些手术技巧,术后可使98%以上的病人恢复正常或接近正常的嗓音功能。     

Benign parathyroid cyst causing vocal fold paralysis: a case report and review of the literature

BACKGROUND: Parathyroid cysts are uncommon, frequently asymptomatic lesions of the neck and superior mediastinum. Symptomatic parathyroid cysts are very rare, with roughly only 200 cases reported in the literature. Of these, only nine cases have been reported with recurrent laryngeal nerve (RLN) paralysis METHODS: We report a case of a 49-year-old man initially seen with a 6-month history of worsening hoarseness. Physical examination revealed a palpable 3-cm, firm, smooth, nontender mass of the right thyroid lobe. Fiberoscopic laryngoscopy showed right vocal cord immobility consistent with RLN paralysis. After CT and fine-needle aspiration of the mass, the patient underwent a right thyroid lobectomy. During surgery, the recurrent laryngeal nerve was found to be stretched and adherent to a right inferior lobe mass. RESULTS: Histologic analysis of the surgical specimen revealed a benign parathyroid adenomatous cyst. Postoperatively, the patient's voice improved markedly. This case represents an extremely rare return of function of the RLN after cyst removal. CONCLUSION: Parathyroid cysts should be included in the differential diagnosis for vocal fold paralysis.     

Recurrent laryngeal nerve and voice preservation: routine identification and appropriate assessment �C two important steps in thyroid surgery

INTRODUCTION

The aims of this study were to assess and compare vocal cord functions before and after thyroid surgery after intra-operative identification of recurrent laryngeal nerve.

PATIENTS AND METHODS

Recurrent laryngeal nerve (RLN) is seen intra-operatively in all cases undergoing thyroid surgeries. Vocal cord functions including any voice change were evaluated by indirect laryngoscopy (I/L) and direct laryngoscopy (D/L) before and after surgery.

RESULTS

Prospective study on 100 patients over 18 months with a total of 146 nerves at risk (NAR). Majority were women (n = 86) with mean age of 37.48 years (range, 13–60 years). RLN was seen in all patients and 19 patients complained of some change in quality of their voice after surgery. Evaluation by I/L and D/L at 6 weeks showed recurrent laryngeal nerve palsy (RLNP) in nine (47.36%) and five (26%) of these 19 patients respectively. Analysed according to total NAR, the incidence of voice change and temporary RLN palsy (I/L and D/L) at 6 weeks was still less at 13.01%, 6.16% and 3.42%, respectively. Voice change improved in all cases at 3 months with no RLNP palsy by I/L or D/L. All these 19 patients had undergone difficult or extensive surgery for malignancy, large gland, extratyhroidal spread or fibrosis.

CONCLUSIONS

Despite identification and preservation of RLN, patients can develop postoperative voice change and RLNP although all voice change cannot be attributed to damaged RLN. Proper assessment of vocal cord functions by I/L and D/L laryngoscopy is required to rule out injuries to these nerves. Risk of damage is higher in patients undergoing more difficult surgery.     

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??Application of intraoperative neromonitoring during complex thyroid operation SUN Hui,LIU Xiao-li,FU Yan-tao,et al.Division of Thyroid Surgery,China-Japan Union Hospital of Jilin University,Changchun 130033, China Corresponding author: SUN Hui,E-mail:sunhui1229@163.com Abstract Objective Apply the intraoperative neuromonitoring ??IONM?? as an adjunct to avoid recurrent laryngeal nerve (RLN) injury during complex thyroid operation. Methods From March 2009 to July 2009, 132 pations (186 nerves at risk) underwent complex thyroidectomy with the application of IONM. Vagus nerve and RLN were tested respectively before and after resection of thyroid lobe. Video recording of cord mobility was performed routinely pre- and postoperatively. Results In addition to 4 cases with preoperative vocal cord paralysis??182 RLN after resection of thyroid lobe with a clear electromyography(EMG) and 0?? nerves experienced signal loss before closing surgical incision showed normal electrical transduction function. Accurately detect non-RLN in 2 nerves. Conclusion IONM could make RLN identification more reliabe and precise, test the functional integrity of RLN. IONM is a useful adjunct to reduce RLN palsy rate in complex thyroid operation.     

Assessment of recurrent laryngeal nerve function during thyroid surgery

Introduction

There is disparity in the reported incidence of temporary and permanent recurrent laryngeal nerve (RLN) palsy following thyroidectomy. Much of the disparity is due to the method of assessing vocal cord function. We sought to identify the incidence and natural history of temporary and permanent vocal cord palsy following thyroid surgery. The authors wanted to establish whether intraoperative nerve monitoring and stimulation aids in prognosis when managing vocal cord palsy.

Methods

Prospective data on consecutive thyroid operations were collected. Intraoperative nerve monitoring and stimulation, using an endotracheal tube mounted device, was performed in all cases. Endoscopic examination of the larynx was performed on the first postoperative day and at three weeks.

Results

Data on 102 patients and 123 nerves were collated. Temporary and permanent RLN palsy rates were 6.1% and 1.7%. Most RLN palsies were identified on the first postoperative day with all recognised at the three-week review. No preoperative clinical risk factors were identified. Although dysphonia at the three-week follow-up visit was the only significant predictor of vocal cord palsy, only two-thirds of patients with cord palsies were dysphonic. Intraoperative nerve monitoring and stimulation did not predict outcome in terms of vocal cord function.

Conclusions

Temporary nerve palsy rates were consistent with other series where direct laryngoscopy is used to assess laryngeal function. Direct laryngoscopy is the only reliable measure of cord function, with intraoperative monitoring being neither a reliable predictor of cord function nor a predictor of eventual laryngeal function. The fact that all temporary palsies recovered within four months has implications for staged procedures.     

NERVE STIMULATION IN THYROID SURGERY: IS IT REALLY USEFUL?

BACKGROUND: Monitoring of the recurrent laryngeal nerve (RLN) has been claimed in some studies to reduce rates of nerve injury during thyroid surgery compared with anatomical dissection and visual identification of the RLN alone, whereas other studies have found no benefit. Continuous monitoring with endotracheal electrodes is expensive whereas discontinuous monitoring by laryngeal palpation with nerve stimulation is a simple and inexpensive technique. This study aimed to assess the value of nerve stimulation with laryngeal palpation as a means of identifying and assessing the function of the RLN and external branch of the superior laryngeal nerve (EBSLN) during thyroid surgery. METHODS: This was a prospective case series comprising 50 consecutive patients undergoing total thyroidectomy providing 100 RLN and 100 EBSLN for examination. All patients underwent preoperative and postoperative vocal cord and voice assessment by an independent ear, nose and throat surgeon, laryngeal examination at extubation and all were asked to complete a postoperative dysphagia score sheet. Dysphagia scores in the study group were compared with a control group (n = 20) undergoing total thyroidectomy without nerve stimulation. RESULTS: One hundred of 100 (100%) RLN were located without the use of the nerve stimulator. A negative twitch response occurred in seven (7%) RLN stimulated (two bilateral, three unilateral). Postoperative testing, however, only showed one true unilateral RLN palsy postoperatively (1%), which recovered in 7 weeks giving six false-positive and one true-positive results. Eighty-six of 100 (86%) EBSLN were located without the nerve stimulator. Thirteen of 100 (13%) EBSLN could not be identified and 1 of 100 (1%) was located with the use of the nerve stimulator. Fourteen per cent of EBSLN showed no cricothyroid twitch on EBSLN stimulation. Postoperative vocal function in these patients was normal. There were no instances of equipment malfunction. Dysphagia scores did not differ significantly between the study and control groups. CONCLUSION: Use of a nerve stimulator did not aid in anatomical dissection of the RLN and was useful in identifying only one EBSLN. Discontinuous nerve monitoring by stimulation during total thyroidectomy confers no obvious benefit for the experienced surgeon in nerve identification, functional testing or injury prevention.     

Acute respiratory failure after deep cervical plexus block for carotid endarterectomy as a result of bilateral recurrent laryngeal nerve paralysis

We report about a case of acute respiratory distress (73-year-old female), which occurred minutes after a deep cervical plexus block (40 ml ropivacaine 0.5%) for carotid endarterectomy (CEA) and required immediate endotracheal intubation of the patient's trachea and consecutive mechanical ventilation. Subsequently, CEA was performed under general anaesthesia (TIVA) with continuous monitoring by somatosensory-evoked potentials. After a period of 14 hours, the endotracheal tube could be removed, the patient being in fair respiratory, cardiocirculatory and neurological conditions. Retrospectively, acute respiratory distress was caused by a combination of ipsilateral plexus blockade-induced and pre-existing asymptomatic contralateral recurrent laryngeal nerve (RLN) paralysis confirmed by a postoperative ENT-check and related to previous thyroid surgery more than 50 years ago. RLN paralysis, often being asymptomatic, represents a typical complication of thyroid and other neck surgery with reported incidences of 0.5-3%. Therefore, a thorough preoperative airway check is advisable in all patients scheduled for a cervical plexus block. Particularly in cases with a history of respiratory disorders or previous neck surgery a vocal cord examination is recommended, and the use of a superficial cervical plexus block may lower the risk of respiratory complications. This may prevent a possibly life-threatening coincidence of ipsilateral plexus blockade-induced and pre-existing asymptomatic contralateral RLN paralysis.     

手术治疗单侧喉返神经麻痹的甲状腺肿瘤

目的分析术前单侧喉返神经麻痹的甲状腺肿瘤患者的临床、病理特点,探讨合理处理受侵喉返神经的方法。方法回顾分析2004年5月～2008年12月收治的2174例甲状腺肿瘤患者的临床资料,其中19例术前诊断单侧喉返神经麻痹,包括结节性甲状腺肿2例,甲状腺恶性肿瘤17例。13例行根治性切除手术,包括双侧甲状腺切除＋颈淋巴结清除术12例,双侧甲状腺切除＋全喉切除术1例,其中6例保留喉返神经,1例切除受侵段神经后予以吻合,另6例切除病变神经;4例行姑息性切除,患侧喉返神经均切除;2例结节性甲状腺肿患者行双侧甲状腺全切除术,喉返神经保护。结果19例患者均无围手术期死亡病例。淋巴结转移者10例。19例均获随访,时间平均64（37～91）月。2例结节性甲状腺肿和6例甲状腺癌术中保留喉返神经者,术后声音改善明显,另1例健侧代偿。6例切除神经者和4例姑息性手术切除喉返神经者术后声音无改善。结论术中探明喉返神经受肿瘤侵犯程度,尽可能保留神经,可以改善患者生活质量,取得较满意治疗效果。     

Validity of intra-operative neuromonitoring signals in thyroid surgery

Background Although intra-operative neuromonitoring (IONM) is widely used in thyroid surgery, the validity of the received IONM signals are still unknown.Method Prospective collection of data forms in 29 hospitals from 8,534 patients with 15,403 nerves at risk, who underwent surgery for benign and malignant goitre disorders between August 1999 and January 2001. IONM was performed by indirect stimulation via the vagal nerve and by direct recurrent laryngeal nerve (RLN) stimulation in 12,486 cases. IONM signals were compared with early (<14 days) and late (6 months) postoperative vocal cord function findings.Results The transient and permanent RLN palsy rate was 2.8% and 0.7%, respectively. Monitoring of the RLN function was significantly more reliable via the indirect IONM stimulation route than via the direct IONM stimulation route (specificity P<0.05). IONM by indirect stimulation via the vagal nerve reliably excluded postoperative, permanent, vocal cord palsy (specificity 97.6%, negative predictive value 99.6%). However, a changed IONM was insufficient to predict permanent RLN palsy (sensitivity 45.9%, positive predictive value 11.6%). IONM was not associated with increased general morbidity.Conclusions For intra-operative neuromonitoring, indirect stimulation of the RLN is superior to direct stimulation. An intact acoustic IONM signal is highly predictive of intact postoperative RLN function. When the IONM signal is abnormal or absent, a one-stage extensive thyroid resection should be performed only if the surgeon is absolutely convinced that the first RLN is not harmed or a total thyroidectomy is mandatory.     

Laryngeal nerve monitoring during thyroid surgery in pregnancy

A 32-week parturient required partial thyroidectomy for suspicious carcinoma. The surgeon requested laryngeal nerve monitoring to decrease the chances of laryngeal nerve injury during surgery. After rapid-sequence induction of general anesthesia and intubation, a size 3 laryngeal mask airway was inserted posterior to the endotracheal tube and the cuff inflated with 15 mL of air. A fiberoptic bronchoscope inserted through the laryngeal mask airway provided an unhindered view of vocal cords for laryngeal nerve identification and testing during surgery. This combined technique also offered the advantages of a secured airway, as well as positive pressure ventilation in the parturient during thyroid surgery.     

The role of ansa-to-recurrent-laryngeal nerve anastomosis in operations for thyroid cancer.

OBJECTIVE: To study the recovery in phonation after reconstruction of the recurrent laryngeal nerve (RLN) in patients whose thyroid cancer was invading the nerve, and to evaluate the role of ansa cervicalis to RLN anastomosis (ARA) in operations for thyroid cancer. DESIGN: Retrospective study. SETTING: University hospital and private thyroid clinic hospital, Japan. SUBJECTS: 34 patients with thyroid cancer who underwent reconstruction of unilateral RLN and 331 consecutive patients operated on for thyroid cancer. INTERVENTIONS: Reconstruction was direct anastomosis (DA), free nerve grafting (FNG), vagus-RLN anastomosis (VRA) or ARA, including anastomosis behind the thyroid cartilage. MAIN OUTCOME MEASURES: Maximum phonation time (34 normal subjects and 26 patients with vocal cord paralysis served as controls), laryngoscopic examination, and the ratio of reconstruction in patients who needed resection of the RLN. RESULTS: The maximum phonation time started to increase rapidly 2-5 months postoperatively in most cases as the patients' voices recovered, and 12 months after reconstruction was significantly longer than in those patients with vocal cord paralysis (P < 0.0001). It was comparable to that of the normal subjects, although the reinnervated cords were fixed in the median. The number of reconstructions in the series of 331 patients increased from 18% to 82% after we started doing ARA with the meticulous technique of anastomosis inside the thyroid cartilage. CONCLUSIONS: ARA is as effective as DA or FNG in improving phonation in patients who need resection of a unilateral RLN. As ARA has several advantages over FNG it has a definite place in operations for thyroid cancer.     

甲状腺手术所致喉返神经损伤的手术治疗

目的探讨甲状腺手术所致喉返神经(RLN)损伤的处理。方法回顾性分析1970至2001年治疗的50例甲状腺手术所致RLN损伤患者的损伤原因、部位、类型、手术治疗方法、随访结果等。结果50例患者共损伤RLN54条(其中双侧神经损伤4例)。损伤部位位于RLN入喉处下方2cm以内者45例支(83．3％),其他部位6例支(11．3％),部位不明3例支(5．4％)。横断性损伤19例支(35．2％),缝扎或瘢痕压迫35例支(64．8％)。54例支神经均经手术修复,4例双侧RLN损伤者同时行气管切开术。术后44例(88．O％)患者获1．5年以上随访,发音恢复正常或明显好转者42例(95．5％);声音好转者2例(4．5％)。35例患者39支神经接受间(直)接喉镜检查,其中声带活动恢复正常的21条(53．8％),部分恢复活动的7条(17．9％),未恢复活动的11条(28．3％)。本组患者发音及声带活动的恢复与修复手术时间及手术方式均无明显关系。结论甲状腺手术所致RLN损伤绝大部分为发生在RLN入喉处附近的机械性损伤,手术可解除病因。RLN损伤一经诊断应尽早行再次手术。