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.     

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 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.     

Pitfalls of Intraoperative Neuromonitoring for Predicting Postoperative Recurrent Laryngeal Nerve Function during Thyroidectomy

Introduction Intraoperative neuromonitoring has been widely adopted to facilitate the identification and preservation of recurrent laryngeal nerve (RLN) function during thyroid surgery. The present prospective study validated the ability of this technique to predict postoperative RLN outcomes in a single endocrine surgical unit. Methods Neuromonitoring was performed using Neurosign 100 with laryngeal surface electrodes in 171 patients with 271 nerves at risk during thyroidectomy. Vocal cord function was routinely documented perioperatively. Patients were also stratified to low risk (primary surgery for benign disease) and high risk (malignancy and recurrent disease) for subgroup analysis. Results Unilateral vocal cord palsy occurred in 15 patients (5.5%) postoperatively. The incidence of postoperative nerve palsy in the low risk and high risk groups was 4.4% and 7.8%, respectively. All but two patients had recovery of function within a median period of 4 months after the operation. The rates of transient and permanent RLN palsy based on nerves at risk were 4.8% (n = 13) and 0.7% (n = 2), respectively. There were 241 true-negative (positive signal and no cord palsy), 15 false-positive (negative signal but no cord palsy), 8 true-positive (negative signal and cord palsy), and 7 false-negative (positive signal but cord palsy) results, as correlated with the postoperative assessment. The sensitivity, specificity, and positive and negative predictive values were 53%, 94%, 35%, and 97%, respectively. For the high risk group, the sensitivity and positive predictive value increased to 86% and 60%, respectively. Conclusions There are pitfalls associated with the use of intraoperative neuromonitoring during thyroid surgery. Routine application is not recommended except for selected high risk patients. This work was presented as a free paper during International Surgical Week 2005, Durban, South Africa, August, 2005.     

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.     

甲状腺手术中常规显露喉返神经的意义

目的 探讨甲状腺手术中常规显露喉返神经(RLN)对保护神经的作用.方法 回顾性分析2009年至2010年间连续实施的232例甲状腺切除手术患者的资料.手术均由同一组医师实施,方式为甲状腺腺叶切除或全切除术,术中常规显露喉返神经.结果 共行腺叶切除181例,甲状腺全切除51例.术中解剖喉返神经280根(98.9%).术后...     

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。     

The role of intraoperative neuromonitoring of recurrent laryngeal nerve during thyroidectomy: a comparative study on 1000 nerves at risk

BACKGROUND: The role of intraoperative neuromonitoring of recurrent laryngeal nerve (RLN) during thyroidectomy has not been well established. The present study evaluates whether RLN injury can be reduced by the application of this technique during thyroidectomy in a single center. METHODS: Of 1000 RLNs that were at risk of injury in 639 consecutive patients who underwent thyroidectomy, the outcome of 501 RLNs with the use of neuromonitoring was compared with that of 499 nerves that were operated by routine identification only. The incidences of RLN paralysis were compared between the 2 groups and the assigned risk subgroups. RESULTS: Postoperative palsy was identified in 47 RLNs (4.7%), with complete recovery in 37 of 44 RLNs (84%) without documented injury. The overall incidence of postoperative RLN paralysis was significantly higher during thyroidectomy for malignancy (P = .025) and secondary thyroidectomy (P = .017). There was no significant difference in postoperative, transient, and permanent paralysis rates between the neuromonitoring and control groups. In subgroup analysis, the postoperative RLN palsy rate was higher during reoperative thyroidectomy (19% vs 4.6%; P = .019) in the control group but not in the neuromonitoring group (7.8% vs 3.8%; P > .05). CONCLUSION: Neuromonitoring of the RLN during thyroid surgery could not be demonstrated to reduce RLN injury significantly, compared with the adoption of routine RLN identification. However, its application can be considered for selected high-risk thyroidectomies.     

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??Intraoperative investigation and the significance of extralaryngeal division of recurrent laryngeal nerve QIAN Jun??SU Yan-jun??ZHANG Jian-ming??et al. Department of Thyroid Surgery, First Affiliated Hospital of Kunming Medical University, Kunming 650032, China
Corresponding author??CHENG Ruo-chuan, E-mail??cruochuan@yahoo.com.cn
Abstract Objective To analyze the frequency of extralaryngeal branching??ELB??of the recurrent laryngeal nerve (RLN) in thyroidectomy and discuss the clinical significance of preserving extralaryngeal branching of RLN. Methods Intraoperative study the ELB of RLN in 1346 patients performed thyroidectomy by the same group of surgeons from January 2009 to January 2011 in the First Affiliated Hospital of Kunming Medical University was performed combined with pertinent literatures reviewed. Results There were 943 patients enrolled in the research. Among them, 1701 RLNs were exposed and indentified (843 in left and 858 in right) and bilateral RLNs were exposed in 758 patients simultaneously. A total of 528 RLNs (31.0%) had extralaryngeal branches (306 in left and 222 RLNs in right), while 218 cases were bilaterally. Bifurcation occurred in 82.4% of the patients, while the other 17.6% were trifurcations. The median distance from branching point to entering point was 7.5mm on the left and 8mm on the right. Branching point above the inferior thyroid artery occurred in 85.6% nerves. There were 8 patients with nerves iatrogenic injured. Among them, 2 patients were temporary and 6 were permanent. Conclusion The incidence of extralaryngeal branching of RLN and location of branching may be varied. However, the motor fiber of RLN is located in the anterior branch which controls the movement of vocal cord. Recognition of the frequent anatomical variation and meticulous preservation of all branches are of great importance to decrease postoperative vocal cord paralysis.     

Does Extralaryngeal Branching Have An Impact on the Rate of Postoperative Transient or Permanent Recurrent Laryngeal Nerve Palsy?

Background  This prospective study assessed the prevalence of the extralaryngeal branching of the recurrent laryngeal nerve (RLN) and its impact on the incidence of postoperative transient or permanent RLN palsy. Methods  Total or hemithyroidectomy was performed in 115 patients, with a total of 195 RLNs displayed. The RLN extralaryngeal branches were routinely identified and preserved. The postoperative course of each patient was evaluated. Outcomes of patients with and without branching RLN were compared. Results  In all, 36 of 195 (18.5%) nerves showed extralaryngeal branching: 27 cases (25.5%) on the right and 9 on the left side (10.1%; p = 0.0088).Trifurcation of the RLN was identified in two dissections (1%). Bilateral bifurcations were observed in 3 of 80 (3.7%) patients. We reported four (2.1%) unilateral permanent RLN palsies, eight cases of unilateral transient nerve palsy (4.1%), and one bilateral transient RLN injury (0.6%). The comparative analysis of postoperative outcomes between branched and nonbranched RLNs revealed that the anatomical variation was more frequently associated both with unilateral permanent RLN palsy (relative risk, 13.25; 95% confidence interval, 1.42–123.73; p = 0.0204) and unilateral transient RLN palsy (relative risk, 7.36; 95% confidence interval, 1.84–29.4; p = 0.0061). The only case of bilateral transient RLN injury was associated with a nonrecurrent inferior laryngeal nerve. Conclusions  Branched RLNs represent a risk factor both for transient and permanent nerve palsy after surgery. Awareness of this anatomical variation and its routine investigation are essential during thyroid surgery to limit its relevant impact on postoperative RLN injury rate.     

甲状腺手术中常规显露喉返神经的意义

目的 探讨甲状腺手术中常规显露喉返神经(RLN)对保护神经的作用.方法 回顾性分析2009年至2010年间连续实施的232例甲状腺切除手术患者的资料.手术均由同一组医师实施,方式为甲状腺腺叶切除或全切除术,术中常规显露喉返神经.结果 共行腺叶切除181例,甲状腺全切除51例.术中解剖喉返神经280根(98.9%).术后10例患者(3.6%)出现声音嘶哑,其中7例术中证实了喉返神经的完整性,但声带检查出现患侧运动障碍,均在术后2个月内发音恢复正常.另外3例为术中离断性神经损伤并行即刻吻合者,在术后4个月内声音均恢复正常.结论 甲状腺手术中常规显露喉返神经是预防喉返神经永久性损伤的有效方法.     

甲状腺手术行喉返神经解剖显露的临床分析

目的探讨甲状腺术中喉返神经的解剖及显露的临床意义,以减少喉返神经损伤。方法回顾性分析965例甲状腺手术患者的临床资料,所有手术均在全嘛下进行并常规显露喉返神经,手术切除范围由病变情况决定,并对喉返神经解剖特点、损伤情况进行分析。结果共解剖显露喉返神经1052条,其中右侧721条,左侧331条,包括双侧87条;采用上方入路解剖86条,侧方661条,下方305条;右侧喉返神经位于气管食管沟内走行者461条,偏离者260条;左侧位于气管食管沟内走行者285条,偏离者46条;喉返神经入喉前有分支者687条（65．3％）,未分支直接人喉者365条（34．7％）;喉不返神经2条;解剖神经平均用时（6．7±0．54）min;术后神经暂时性损伤11例,永久性损伤2例,均于6个月后对侧声带代偿,嘶哑改善。结论熟悉喉返神经的解剖,灵活运用不同的解剖入路,常规解剖显露神经,是避免喉返神经损伤的有效方法。     

A prospective evaluation of recurrent laryngeal nerve paralysis during thyroidectomy

HYPOTHESIS: Recurrent laryngeal nerve paralysis after thyroidectomy can be unrecognized without routine laryngoscopy, and patients have a good potential for recovery during follow-up. DESIGN: A prospective evaluation of vocal cord function before and after thyroidectomy. Periodic vocal cord assessment was performed until recovery of cord function. Persistent cord palsy for longer than 12 months after the operation was regarded as permanent. SETTING: A university hospital with about 150 thyroid operations performed by 1 surgical team per year. PATIENTS: From January 1, 1995, to April 30, 1998, 500 consecutive patients (84 males and 416 females) with documented normal cord function at the ipsilateral side of the thyroidectomy were studied. MAIN OUTCOME MEASURES: Vocal cord paralysis after thyroidectomy. RESULTS: There were 213 unilateral and 287 bilateral procedures, with 787 nerves at risk of injury. Thirty-three patients (6.6%) developed postoperative unilateral cord paralysis, and 5 (1.0%) had recognizable nerve damage during the operations. Complete recovery of vocal cord function was documented in 26 (93%) of 28 patients. The incidence of temporary and permanent cord palsy was 5.2% and 1.4% (3.3% and 0.9% of nerves at risk), respectively. Among factors analyzed, surgery for malignant neoplasm and recurrent substernal goiter was associated with an increased risk of permanent nerve palsy. Primary operations for benign goiter were associated with a 5.3% and 0.3% incidence (3.4% and 0.2% of nerves at risk) of transient and permanent nerve palsy, respectively. CONCLUSIONS: Unrecognized recurrent laryngeal nerve palsy occurred after thyroidectomy. Thyroid surgery for malignant neoplasms and recurrent substernal goiter was associated with an increased risk of permanent recurrent nerve damage. Postoperative vocal cord dysfunction recovered in most patients without documented nerve damage.     

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.     

Is there a role for routine laryngoscopy before and after parathyroid surgery?

Introduction

Recurrent laryngeal nerve (RLN) palsy is a potential complication of parathyroid surgery with significant morbidity and a cause of medico-legal litigation. Peri-operative laryngoscopy to assess RLN function helps identify a vocal cord palsy and guide management. The value of its routine use in asymptomatic patients is however unclear. The low risk of permanent palsy, rarity of true asymptomatic palsy and costs, discomfort and inconvenience to patients are arguments against routine laryngoscopy. This study assessed the results of routine laryngoscopy in patients having parathyroid surgery for primary hyperparathyroidism (PHPT).

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.     

甲状腺手术中显露喉返神经以避免喉返神经损伤的临床意义

目的探讨甲状腺手术中显露喉返神经(RLN)对预防RLN损伤的临床意义。方法回顾性分析2006年9月至2011年8月期间我院行甲状腺全切除术和次全切除术1 723例患者的临床资料,其中行显露RLN术式914例,共显露RLN 1 203条;行不显露RLN术式809例,共行1 013侧甲状腺腺叶切除手术。比较术后RLN损伤情况及术后6个月声带恢复情况。结果显露组与不显露组RLN损伤发生率分别为0.91%(11/1 203)和2.07%(21/1 013),2组比较差异有统计学意义(P<0.05)。术后随访6个月,显露组与不显露组分别有0例和13例(61.9%,13/21)永久性RLN损伤,2组比较差异有统计学意义(P<0.01)。结论在甲状腺全切除和次全切除术中,显露并注意保护RLN能最大程度地避免RLN损伤,尤其是永久性RLN损伤。     

The use of readily available equipment in a simple method for intraoperative monitoring of recurrent laryngeal nerve function during thyroid surgery: initial experience with more than 300 cases

HYPOTHESIS: An inexpensive and widely applicable technique to monitor recurrent laryngeal nerve (RLN) function during thyroid surgery can be safely implemented. DESIGN: Consecutive sample. SETTING: Single-surgeon academic practice. PATIENTS: Three hundred sixty-three consecutive patients undergoing surgery for thyroid disease in the 18 months from November 1, 1999, to May 31, 2001. INTERVENTIONS: Anesthetic management using laryngeal mask airway and spontaneous ventilation, combined with electrical RLN stimulation and fiberoptic video laryngoscopy to confirm vocal cord response. MAIN OUTCOME MEASURES: Vocal cord response to RLN stimulation, intraoperative anatomic findings, postoperative voice quality, and anesthetic complications. RESULTS: We used the laryngeal mask airway-based technique in 327 cases. Visualization of vocal cords was maintained throughout the surgery in 310 cases (95%). In 10 cases (3%), the branch of the RLN carrying vocal cord function could not be identified until electrical testing was performed. A single inadvertent RLN palsy was seen in 1 of the 17 cases in which vocal cord visualization was lost during the procedure (0.03% overall). Upper airway obstruction occurred in 16 (5%) of 327 attempted procedures, requiring tracheal intubation in 3 (1%). No further complications regarding airway management were seen. Pneumothorax was observed in 5 cases (2%), each of which resolved without chest tube placement. CONCLUSIONS: This technique can be applied to thyroid surgery as a safe means of managing the airway. It is associated with an ability to test RLN function at will in more than 95% of cases using readily available equipment.     

Influence of the Refinement of Surgical Technique and Surgeon’s Experience on the Rate of Complications after Total Thyroidectomy for Benign Thyroid Disease

Background: In recent years, many surgeons dealing with endocrine surgery have increasingly performed total thyroidectomy for benign thyroid disease. However, total excision of the thyroid in the treatment of benign lesions has been surrounded by even more controversy than its role in cancer treatment. The complication rate appears to be higher when the operation is done by inexperienced surgeons who have no special skills in endocrine surgery using proper techniques. The aim of this study is to determine whether surgeons experience and the refinement of surgical techniques are associated with postoperative recurrent laryngeal nerve (RLN) palsy or hypocalcemia after total thyroidectomy for benign thyroid disease.

Methods: A total of 68 consecutive patients who underwent total thyroidectomy for benign thyroid disease were reviewed. Twenty-six of these were from between January 1998 and June 1999 (first period) and 42 from between June 1999 and September 2000 (second period). Patients were divided into two subgroups according to different periods and different surgical techniques to identify the RLNs and the parathyroid glands. RLNs function was evaluated pre-and post-operatively by an otolaryngologist, and serum calcium levels were measured at the postoperative follow-up. Results: During the first period of the study, transient hypocalcaemia was determined in 8 (31%) patients. Hypocalcaemia was clinically symptomatic in 5 (19%) patients. Transient RLN palsy developed in 4 (15%) patients. Unilateral permanent RLN palsy due to operative injury was observed in 1 (4%) patient. During the second period, we noted transient hypocalcemia in 11 (26%) patients and symptomatic hypocalcemia in 6 (4%) patients. Serum calcium levels returned to normal within 4 weeks after operation in all patients. Neither transient nor permanent RLN palsy was observed during this period.

Conclusions: Complications of total thyroidectomy can be minimized with increasing experience and the refinement of surgical technique.     

Utility of the continuous intraoperative neuromonitoring in the prevention of the recurrent laryngeal nerve paralysis during thyroid surgery. A prospective observational study

BackgroundThe continuous intraoperative neuromonitoring (C-IONM) of the recurrent laryngeal nerve (RLN) could help reducing the incidence of nerve paralysis after thyroid surgery, in comparison with the mere anatomical visualization of the RLN. The objective is to assess the efficacy and utility of C-IONM as a predictive test for recurrent laryngeal nerve paralysis after thyroidectomy.MethodsA prospective observational study was performed in 248 patients who underwent thyroid surgery where C-IONM was applied, between September 2018 and December 2019, in a high-volume center. A previous and later laryngoscopy was performed, which allowed to evaluate the reliability of the C-IONM as a predictive test for recurrent paralysis. Sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) were studied.ResultsA total number of 171 thyroidectomies, 62 hemithyroidectomies, 15 totalization thyroidectomies and 27 thyroidectomy with cervical dissections were performed. Postoperative laryngoscopy was altered in 40 patients (16.12%). The SE, SP, PPV and NPV values ​​were 65%, 94.7%, 70.2% and 93.4% respectively.ConclusionsC-IONM is a safe technique that provides real-time information about anatomical and functional integrity of the RLN and can improve the results of thyroid surgery.