Minimally invasive thyroid surgery for diagnostic excision of solitary thyroid nodules

OBJECTIVE: Various techniques for minimally invasive thyroid surgery (MITS), including endoscopic and video-assisted procedures, have now been described. Based on our units experience with minimally invasive parathyroidectomy via a lateral incision, a similar technique for minimally invasive thyroid lobectomy has been developed and assessed. METHODS: The last 203 consecutive thyroid procedures using the MITS technique, performed between July 2002 and June 2006, comprised the study group. Inclusion criteria for initial surgery were: initial nodule < 3.0 cm; no preoperative evidence of malignancy; absence of clinical multinodular change. A 2.5-cm lateral incision, using a headlight illumination, provided optimal exposure. RESULTS: A total of 202 patients underwent 203 MITS procedures over the 4-year period, with one patient undergoing bilateral MITS. The procedures included 155 thyroid lobectomies and 48 nodule excisions; 31 of the patients underwent a minimally invasive parathyroidectomy (MIP) during which an ipsilateral thyroid nodule was removed. The mean tumour size was 17.3 mm, but the mean size of the thyroid lobe removed was 39.5 mm. Final diagnoses included benign multinodular goitre (26%), follicular adenoma (22%) and carcinoma (20%). The complication rate was low, with one permanent recurrent laryngeal nerve (RLN) palsy (anterior division only) (0.5%), four RLN neuropraxias which recovered (2%), and one haematoma not requiring re-operation (0.5%). The rate of complications was not significantly different from 819 conventional open hemithyroidectomies performed over the same period. CONCLUSION: MITS is a safe and feasible alternative to open thyroid surgery in appropriately selected cases. It offers a valuable option for diagnostic excision biopsy in patients with thyroid nodules demonstrating an atypical fine-needle biopsy whilst avoiding the need for a standard cervical "collar" incision.     

Minimal access thyroid surgery: technique and report of the first 25 cases

BACKGROUND: Minimal access thyroid surgery, using various techniques, is increasingly being reported. The present study reviews our experience with thyroid surgery using a lateral focused mini-incision approach, and assesses its safety and feasibility. METHODS: The study group comprised all patients undergoing minimal access thyroid surgery (MATS) during the period May 2002-May 2003. Data were prospectively gathered, including patient demographics, indication for surgery, operation performed, nodule size, final pathology, and complications. Exclusion criteria for this procedure included: family history of thyroid cancer, previous neck irradiation or surgery, carcinoma on fine needle aspiration, presence of significant thyroiditis, multinodular goitre, and nodule size >3 cm. The operation was carried out through a 2.5-cm lateral incision placed directly over the nodule, with exposure gained by dissecting the plane between the sternomastoid muscle and the lateral edge of the strap muscles. RESULTS: Twenty-five patients underwent MATS, 22 women and three men. Nineteen patients underwent hemithyroidectomy, five underwent isthmectomy, and one underwent local nodule excision. The average measured incision size was 2.63 cm at the end of the procedure. The average nodule size was 2.2 cm, and the average thyroid lobe resected measured 4.7 cm in maximal length. Final pathology revealed benign nodules in 21 patients and four thyroid cancers (two follicular and two papillary). There was one wound infection and two patients had temporary recurrent laryngeal nerve neuropraxia. CONCLUSION: Minimal access thyroid surgery is a safe and feasible alternative to open thyroid surgery in selected cases.     

Modification of the Surgical Strategy for the Dissection of the Recurrent Laryngeal Nerve Using Continuous Intraoperative Nerve Monitoring

Background

The aim of this study was to describe first experiences and changes in management using continuous intraoperative neuromonitoring (C-IONM) in thyroid and parathyroid surgery.

Method

Retrospective analysis of patients who underwent surgery with C-IONM since 2012. Surgical maneuvers were modified when electrophysiologic events occurred. Patients with persistent loss of signal (LOS) underwent postoperative laryngoscopy.

Results

One hundred and one patients (of 1586 neck surgeries) were included and 19 had events: In 13 these were temporary (resolved before end of surgery) and led to intraoperative modifications in surgical approach; in all cases traction was released, and in 8, recurrent laryngeal nerve (RLN) approach was changed [superior approach (2), inferior approach (2), both (4)]. Six patients had persistent LOS (5.9%, present at end of procedure), with RLN palsy (RLNP) on postoperative day 1: In three, LOS occurred at electrode placement on the vagus nerve, leading to distal placement of the electrode allowing ipsilateral dissection under continuous monitoring; all three had complete recovery at 6 months. In the three other patients, LOS occurred on the RLN: one probable thermal, one traction lesion and one accidental section of the anterior RLN branch. The RLN recovered within 6 months in two patients, and in the third, RLNP persisted after 6 months (1/101 = 1%).

Conclusion

C-IONM provides real-time evaluation of the RLN function, allowing for adaptation of surgical maneuvers to prevent RLNP. It seems particularly useful in difficult cases like redo neck surgery, invasive thyroid cancer and intrathoracic or large goiter. Care should be given at electrode placement on the vagus nerve.

     

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.     

Minimal access thyroid surgery: Is it feasible,is it appropriate?

Background: Reports of minimal access thyroid surgery (MATS) using various techniques have recently appeared. This study examined the feasibility of MATS using either a lateral ‘focused’ or endoscopically assisted approach. Methods: The study group comprised all patients undergoing minimally invasive parathyroidectomy (MIP) during the period May 1998 to April 2002 in whom a concomitant thyroid procedure was undertaken. All procedures were performed either through a 2‐cm lateral cervical incision (n = 19) or endoscopically (n = 7). Results: Twenty‐six patients underwent thyroid surgery, consisting of either local excision of a thyroid nodule (n = 25) or hemi­thyroidectomy (n = 1). In 13 patients the nodule was incidentally discovered, in four patients removal of the parathyroid necessitated partial thyroidectomy, and in nine patients the lesion identified by preoperative parathyroid localization proved to be a thyroid nodule. There were no permanent complications in the study group. Two patients required drainage of a haematoma. The final pathology of all 26 cases revealed benign nodular thyroid disease. Conclusion: Thyroid surgery can safely be performed as a minimally invasive procedure. Minimal access thyroid surgery is therefore a feasible option for selected patients. The question remains to be answered as to whether this surgical approach is appropriate treatment for nodular thyroid disease.     

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。     

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.     

Recurrent laryngeal nerve palsy after thyroidectomy with routine identification of the recurrent laryngeal nerve

BACKGROUND: The aim of this study was to assess the risk of recurrent laryngeal nerve palsy (RLNP) after thyroidectomy with routine identification of the recurrent laryngeal nerve (RLN) during the operation. METHODS: The present study was confined to 521 patients, 348 total lobectomies and 178 total thyroidectomies, treated by the same surgeon. Temporary and permanent RLNP rates were analyzed for patient groups with stratification of primary operation for benign thyroid disease, thyroid cancer, Graves' disease, and reoperation. Measurement of the RLNP rate was based on the number of nerves at risk. Twenty-six RLNs in 20 thyroid cancer patients with intentional sacrifice were excluded from analysis. RESULTS: Forty RLNs (40 patients) developed postoperative RLNP. Complete recovery of RLN function was documented for 35 of the 37 patients (94.6%) whose RLN integrity had been ensured intraoperatively. Recovery from temporary RLNP ranged from 3 days to 4 months (mean, 30.7 days). Overall incidence of temporary and permanent RLNP was 5.1% and 0.9%, respectively. The rates of temporary/permanent RLNP were 4.0/0.2%, 2.0/0.7%, 12.0/1.1%, and 10.8/8.1% for groups classified according to benign thyroid disease, thyroid cancer, Graves' disease, and reoperation, respectively. CONCLUSIONS: Operations for thyroid cancer, Graves' disease, and recurrent goiter demonstrated significantly higher RLNP rates. Invasion of RLN was identified in 19.4% of patients with thyroid cancer. Postoperatively, the RLN recovered in most of the patients without documented nerve damage during the operation. Total lobectomy with routine RLN identification is recommended as a basic procedure in thyroid operations.     

喉返神经隧道解剖法结合神经监测在腔镜甲状腺手术中的应用

目的:探讨喉返神经隧道解剖法结合神经监测在腔镜甲状腺手术中的应用价值。方法:回顾分析2014年11月至2018年12月施行的141例腔镜甲状腺手术,术中均采用喉返神经隧道解剖法结合神经监测技术。其中甲状腺良性结节93例,甲状腺恶性肿瘤48例;行单侧腺叶切除术52例,单侧甲状腺癌根治术44例,双侧甲状腺癌根治术4例,41例部分切除术。结果:140例手术顺利完成,1例因喉返神经横断伤转开放手术行神经对端吻合;术后9例(9/141,6.38%)暂时性神经麻痹,无永久性声音嘶哑患者。结论:腔镜甲状腺手术中采用喉返神经隧道解剖法结合神经监测技术可快速定位喉返神经,降低手术难度,提高手术安全性,利于腔镜甲状腺手术更好地在基层医院推广普及。     

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.     

显露喉返神经在甲状腺切除术中的临床意义

目的探讨甲状腺手术中显露喉返神经对防止喉返神经损伤的价值。方法回顾性分析2 481例甲状腺手术患者的临床资料,其中术中显露喉返神经组1 425例和非显露喉返神经组1 056例,比较两组间并发喉返神经损伤的几率。结果显露喉返神经组喉返神经暂时性损伤31例,损伤率为2.18%,无永久损伤病例;非显露喉返神经组喉返神经损伤44例,损伤率为4.17%,其中暂时损伤39例,永久损伤为5例。两组喉返神经损伤率比较差异有统计学意义(P<0.01)。结论甲状腺手术术中显露喉返神经对保护喉返神经是安全和有效的,对预防或避免医源性喉返神经损伤有重要意义。     

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。     

Intraoperative Nerve Monitoring Can Reduce Prevalence of Recurrent Laryngeal Nerve Injury in Thyroid Reoperations: Results of a Retrospective Cohort Study

Background

The prevalence of recurrent laryngeal nerve (RLN) injury is higher in repeat than in primary thyroid operations. The use of intraoperative nerve monitoring (IONM) as an aid in dissection of the scar tissue is believed to minimize the risk of nerve injury. The aim of this study was to examine whether the use of IONM in thyroid reoperations can reduce the prevalence of RLN injury.

Methods

This was a retrospective cohort study of patients who underwent thyroid reoperations with IONM versus with RLN visualization, but without IONM. The database of thyroid surgery was searched for eligible patients (treated in the years 1993–2012). The primary outcomes were transient and permanent RLN injury. Laryngoscopy was used to evaluate and follow RLN injury.

Results

The study group comprised 854 patients (139 men, 715 women) operated for recurrent goiter (n = 576), recurrent hyperthyroidism (n = 36), completion thyroidectomy for cancer (n = 194) or recurrent thyroid cancer (n = 48), including 472 bilateral and 382 unilateral reoperations; 1,326 nerves at risk (NAR). A group of 306 patients (500 NAR) underwent reoperations with IONM and 548 patients (826 NAR) had reoperations with RLN visualization, but without IONM. Transient and permanent RLN injuries were found respectively in 13 (2.6 %) and seven (1.4 %) nerves with IONM versus 52 (6.3 %) and 20 (2.4 %) nerves without IONM (p = 0.003 and p = 0.202, respectively).

Conclusions

IONM decreased the incidence of transient RLN paresis in repeat thyroid operations compared with nerve visualization alone. The prevalence of permanent RLN injury tended to be lower in thyroid reoperations with IONM, but statistical validation of the observed differences requires a sample size of 920 NAR per arm.     

Initial experience with S-shaped electrode for continuous vagal nerve stimulation in thyroid surgery

Background

In thyroid surgery, intra-operative neuromonitoring of the recurrent laryngeal nerve (RLN) and vagal nerve (VN) are performed as an adjunct to the gold standard of optical visualisation of the RLN, to avoid injury of the RLN, and subsequently paralysis of the vocal cords. Intermittent RLN neuromonitoring diminished the temporary RLN palsy rate, but continuous neuromonitoring could have to potential of avoiding any damage. Since no study evaluated continuous vagal stimulation before, the objective of this study was to evaluate continuous neuromonitoring in a clinical setting, to assess its’ value in predicting vocal cord injury.

Methods

A single centre prospective study was performed from September 2010 till February 2012, including 100 consecutive thyroidectomies with continuous VN stimulation using an S-shaped electrode.

Results

In this study, 100 thyroidectomies (80 total thyroidectomies and 20 hemi-thyroidectomies) were analysed. On 180 nerves at risk (NAR), there were four RLN palsies (2.2 %), of which only one definitive. In the cases with temporary palsies, an intra-operative diminution of the amplitude occurred, recovering partially with release of traction. Loss of signal was seen in all four cases, with an abrupt loss of signal in the definitive one. The RLN function remained intact in the other 176 NAR.

Conclusion

Continuous neuromonitoring of the VN is accurate and precise in predicting vocal cord palsy. It is of tremendous importance that the vagal electrode is a-traumatic and gives a stable signal. The exact parameters regarding “warning signs” have yet to be determined, but amplitude changes seem to play a major role.     

Intermittent Intraoperative Neural Monitoring Technology in Minimally Invasive Video-Assisted Thyroidectomy: A Preliminary Study

Purpose: Intraoperative neural monitoring (IONM) technology was applied in minimally invasive video-assisted thyroidectomy (MIVAT) to explore its safety and effectiveness. Materials and Methods: Data were collected retrospectively from October 2009 to August 2011. Inclusion criteria included the following: (1) benign thyroid nodule with maximum diameter less than 4.0 cm by preoperative ultrasound evaluation; (2) no previous thyroid surgeries; (3) no cervical radiation history; (4) normal function of recurrent laryngeal nerve (RLN) examined by preoperative laryngoscopy; (5) patients who did not accept to take a “wait and see” follow-up strategy. Enrolled patients were randomly allocated into NIM group and control group. Results: 46 patients were enrolled in NIM group, and 51 patients were enrolled in control group. All surgeries in NIM group were performed successfully, and majority of tracheal intubations were placed with one attempt. 47 RLNs in NIM group and 60 RLNs in control group were exposed. The time of RLN locating was 6.06 ± 1.48 min in NIM group and 6.92 ± 1.34 min in control group (p = .02). The time of RLN tracing and exposing was 28.96 ± 4.75 min in NIM group and 32.17 ± 5.56 min in control group (p = .02). 1 case of temporary RLN paralysis was observed in both groups, and no permanent RLN paralysis was reported. Conclusions: The application of intermittent IONM in MIVAT is feasible. Intermittent IONM can help reduce the time of RLN locating and the time of RLN tracing and exposing.     

Is dysphonia permanent or temporary after anterior cervical approach?

The rate, causes and prognosis of dysphonia after anterior cervical approach (ACA) were investigated in our clinical series. During a 10-year interval, 235 consecutive patients with cervical disc disease underwent surgical treatment using anterior approach. Retrospective chart reviews showed recurrent laryngeal nerve (RLN) injury in 3 (1.27%) patients. All three patients were men and only one patient had multilevel surgery. These patients had RLN injury after virgin surgery. Laryngoscopic examination demonstrated unilateral vocal cord paralysis in all patients who had postoperative dysphonia. No permanent dysphonia was observed in our series and patients recovered after a mean of 2 months (range 1–3 months) duration. Dysphonia after ACA was a rare complication in our clinical series. Pressure on RLN or retraction may result in temporary dysphonia.     

喉返神经的显露在甲状腺癌根治术中的意义

目的探讨喉返神经的显露在甲状腺癌根治性手术中的意义。方法回顾分析2003年7月至2006年12月间186例主动显露喉返神经的甲状腺癌根治手术病例资料。结果186例甲状腺癌均施行甲状腺全切或近全切除术。术中均成功显露双侧喉返神经,其中1例右侧非返喉下神经。喉返神经永久性损伤1例,暂时性损伤1例,永久损伤率为0．54％。结论甲状腺癌根治术中应常规在甲状腺下动脉周围寻找喉返神经,主动显露喉返神经不仅可减少喉返神经损伤的发生率,并可提高甲状腺癌手术的彻底性。     

Continuous intraoperative neural monitoring in thyroid surgery: a Mexican experience

Intraoperative continuous neural monitoring (C-IONM) during thyroid surgery has been recognized as a useful tool to identify and confirm recurrent laryngeal nerve integrity. The aim of the present study is to analyze electromyographic features and thresholds for normal vocal fold function in our initial experience with C-IONM in thyroid surgery. C-IONM was utilized in 57 patients who underwent thyroid surgery between July 2012 and December 2015. EMG parameters were analyzed looking for potential predictors of postoperative vocal fold dismotility. There were 54 females (94.7%) and 3 males (5.3%) with a mean age of 46.7 ± 11.6 years. C-IONM was successfully registered in 89 of 107 nerves at risk (83.1%). Mean basal amplitude was 727.31 ± 471.25 μV and mean final amplitude was 650.27 ± 526.87 μV (P = 0.095, CI 95% 13.83–167.91). Mean basal latency was 5.23 ± 1.42 mS and mean final latency was 5.18 ± 1.50 mS (P = 0.594, CI 95% 0.39–0.24). Four patients had transient postoperative vocal fold paresis. None of these four patients had loss of signal (LOS), three had transient decrease in amplitude, and one had a normal registry throughout the operation. C-IONM is a useful tool to identify patients in whom intraoperative RLN is at risk during surgery. Final amplitude above 500 μV and no LOS is associated with RLN integrity and normal postoperative vocal fold function.     

喉返神经监测仪在甲状腺再次手术中的临床价值

目的探讨喉返神经探测仪在甲状腺再次手术中的临床应用价值。方法 65例患者采用采用美国Medtronic Xomed公司生产的NIM-Response 3.0行术中喉返神经监测,50例患者采用常规手术暴露喉返神经,比较两组患者在术后暂时性喉返神经损伤率、永久性喉返神经损伤率、确认喉返神经发现时间、手术操作时间的差异。结果暂时性喉返神经损伤率、永久性喉返神经损伤率在术中监测组的均要比常规手术低,为1.53% vs 8.0%(P0.01)、0 vs 4.0%(P0.01);术中监测组喉返神经确认时间及手术时间均比常规手术暴露组低,为5.56±1.95 min vs15.92±2.69 min(P0.001,t=-23.94)、113.90±9.40 min vs 132.40±21.40 min(P0.001,t=-6.23)。结论和常规手术相比,术中喉返神经监测能显著降低术后喉返神经损伤率,而且确认喉返神经和手术时间均能明显降低,缩短手术时间。     

Recurrent Laryngeal Nerve Diameter Increases During Thyroidectomy

Background

Temporary recurrent laryngeal nerve (RLN) palsy after thyroidectomy is usually due to a neurapraxia. Voice changes after thyroidectomy, in the absence of RLN palsy, are common. We postulated that this is due to edema and consequent increased diameter of the RLN during thyroidectomy. The aim of this study was to document changes in the diameter of the RLN during surgery.

Methods

A consecutive series of 110 RLNs was prospectively analyzed in 75 patients. The RLN was measured on identification and removal of the lobe. Electromyogram (EMG) amplitudes were recorded concurrently after neurostimulation. Univariate and multivariate analyses were performed.

Results

The mean increase in RLN diameter was 0.71 from 1.95 mm (P < 000.1). Right and left RLNs were similar diameter. On univariate and multivariate analysis, factors predictive of increased RLN diameter were increasing age (P = 0.04) and increased difference in EMG amplitude (P = 0.01). There was a mean increased EMG amplitude of 101 from 493.5 μV (P < 0.001). On univariate and multivariate analyses, factors predictive of increased difference in EMG amplitude were decreasing age (P = 0.01) and increased difference in RLN diameter (P = 0.02). There was a statistically significant positive relationship between increased diameter of RLN and increased EMG amplitude (R ² = 0.04). The temporary RLN palsy rate was 3%.

Conclusions

The small numbers of temporary RLN palsies prevent correlation with increased diameter of RLN. However, this may explain voice changes after thyroidectomy without RLN palsy. The observed increase in RLN diameter is probably due to edema; its cause is unknown. The increased EMG amplitude seen with increasing RLN diameter may reflect increased excitability of ionic channels in neurons.