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.     

Functional Laryngeal Results after Thyroidectomy and Extensive Recurrent Laryngeal Nerve Dissection without Neuromonitoring

Summary BACKGROUND: Permanent recurrent laryngeal nerve palsy (RLNP) is a major complication after thyroid surgery. Therefore methods are mandatory which reduce this complication. One strategy is the identification and dissection of the recurrent laryngeal nerve (RLN) in all patients as an inflexible rule. It is an ongoing discussion whether RLN neuromonitoring is helpful. METHODS: We prospectively investigated 624 surgical patients with 1076 nerves at risk (NAR) after hemithyroidectomy or total thyroidectomy because of a benign thyroid pathology (BT). In all patients, extensive nerve dissection was performed. Electrophysiological neuromonitoring was not used. All patients were investigated both pre- and postoperatively for regular laryngeal function, using indirect laryngoscopy and videostroboscopy. RESULTS: 2.4 % temporary and 0.3 % permanent RLNPs were documented respectively. CONCLUSIONS: Reviewing the literature, the total rates of (temporary and permanent) RLNPs are identical or lower in studies performing RLN dissection compared to those where no RLN dissection had been performed. Performing RLN dissection reduced the rate of permanent RLNPs. However, our results do not imply that neuromonitoring decreases the rate of permanent RLNP, since studies that included neuromonitoring did not reveal better data. Our observations also suggest that besides indirect laryngoscopy, videostroboscopy should be performed in all patients with no evidently normal bilateral laryngeal function and no normal voice quality. Failing this, the rate of false positive or negative identification of RLNP is likely to increase.     

Intraoperative Monitoring of the Recurrent Laryngeal Nerve in Thyroid Surgery

BACKGROUND: Recurrent laryngeal nerve (RLN) palsy ranks among the leading reasons for medicolegal litigation of surgeons because of its attendant reduction in quality of life. As a risk minimization tool, intraoperative nerve monitoring (IONM) has been introduced to verify RLN function integrity intraoperatively. Nevertheless, a systematic evidence-based assessment of this novel health technology has not been performed. METHODS: The present study was based on a systematic appraisal of the literature using evidence-based criteria. RESULTS: Recurrent laryngeal nerve palsy rates (RLNPR) varied widely after thyroid surgery, ranging from 0%-7.1% for transient RLN palsy to 0%-11% for permanent RLN palsy. These rates did not differ much from those reported for visual nerve identification without the use of IONM. Six studies with more than 100 nerves at risk (NAR) each evaluated RLNPR by contrasting IONM with visual nerve identification only. Recurrent laryngeal nerve palsy rates tended to be lower with IONM than without it, but this difference was not statistically significant. Six additional studies compared IONM findings with their corresponding postoperative laryngoscopic results. Those studies revealed high negative predictive values (NPV; 92%-100%), but relatively low and variable positive predictive values (PPV; 10%-90%) for IONM, limiting its utility for intraoperative RLN management. CONCLUSIONS: Apart from navigating the surgeon through challenging anatomies, IONM may lend itself as a routine adjunct to the gold standard of visual nerve identification. To further reduce the number of false negative IONM signals, the causes underlying its relatively low PPV require additional clarification.     

Systematic review with meta-analysis of studies comparing intraoperative neuromonitoring of recurrent laryngeal nerves versus visualization alone during thyroidectomy

Background

The role of intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) during thyroid surgery is still debatable. The aim of this meta-analysis was to evaluate the potential improvement of IONM versus RLN visualization alone (VA) in reducing the incidence of vocal cord palsy.

Methods

A literature search for studies comparing IONM versus VA during thyroidectomy was performed. Studies were reviewed for primary outcome measures: overall, transient, and permanent RLN palsy per nerve and per patients at risk; and for secondary outcome measures: operative time; overall, transient and permanent RLN palsy per nerve at low and high risk; and the results regarding assistance in RLN identification before visualization.

Results

Twenty studies comparing thyroidectomy with and without IONM were reviewed: three prospective, randomized trials, seven prospective trials, and ten retrospective, observational studies. Overall, 23,512 patients were included, with thyroidectomy performed using IONM compared with thyroidectomy by VA. The total number of nerves at risk was 35,513, with 24,038 nerves (67.7%) in the IONM group, compared with 11,475 nerves (32.3%) in the VA group. The rates of overall RLN palsy per nerve at risk were 3.47% in the IONM group and 3.67% in the VA group. The rates of transient RLN palsy per nerve at risk were 2.62% in the IONM group and 2.72% in the VA group. The rates of permanent RLN palsy per nerve at risk were 0.79% in the IONM group and 0.92% and in the VA group. None of these differences were statistically significant, and no other differences were found.

Conclusions

The current review with meta-analysis showed no statistically significant difference in the incidence of RLN palsy when using IONM versus VA during thyroidectomy. However, these results must be approached with caution, as they were mainly based on data coming from non–randomized observational studies. Further studies including high-quality multicenter, prospective, randomized trials based on strict criteria of standardization and subsequent clustered meta-analysis are required to verify the outcomes of interest.     

Intraoperative Neuromonitoring in Thyroid Surgery

Summary BACKGROUND: Employment of intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) is not unusual nowadays. But up to now, no prospective beneficial studies have been available that evaluate whether the additional use of IONM is beneficial and safe in comparison with conventional thyroid surgery. METHODS: Between 1 August 1999 and 31 January 2001, surgery for benign and malignant goitre was performed on 8900 patients with 16148 nerves at risk. Twenty-eight German hospitals participated. Data were collected prospectively by a questionnaire. Employment of IONM depended on the performing surgeon and was not randomized or controlled. RESULTS: IONM was used in 95.9% (range 57.2–100%) of all thyroid operations. The use of IONM significantly decreased the early RLN palsy rate (3.3% vs. 4.9%; P = 0.04). As for the permanent RLN palsy rate, there was still an advantage gained by using IONM (0.7% vs. 0.9%); however, this difference lacked statistical significance. Overall, IONM was beneficial in high-risk procedures such as recurrent goitre, thyroid carcinoma and extended resections. Employment of the translaryngeal needle electrode of IONM has no influence on general morbidity such as haematomas or wound infections. CONCLUSIONS: The technique of IONM of the RLN in thyroid surgery is safe and decreases the overall RLN palsy rate. IONM in thyroid surgery is especially recommended in high-risk procedures such as recurrent goitre, thyroid carcinoma and extended resections.     

Intraoperative neuromonitoring of the recurrent laryngeal nerve - results and learning curve

Intraoperative neuromonitoring was introduced in thyroid surgery several years ago resulting in a facilitated identification of the recurrent laryngeal nerve and less recurrent laryngeal nerve injuries. Between 1999 and 2004 data of all patients (n=937) undergoing thyroid resection were recorded prospectively and analyzed yearly. The intraoperative identification of recurrent laryngeal nerve succeeded in 99.2% (1665 nerves at risk). The percentage of completely resecting surgical procedures raised from 17% to 56%. Minimal vocal cord dysfunction associated with hematoma and edema in most cases was diagnosed laryngosopically in 1.4-2.4%. Transient recurrent nerve palsies were seen in 2.3% without changes throughout the years.The permanent palsy rate of 0.8% in the first years decreased. No permanent palsies were diagnosed in the last 3 years. Routine introduction of intraoperative neuromonitoring in thyroid surgery is associated with a demonstrable learning curve lasting several years. Permanent palsy rate is decreased. The rate of minimal vocal cord movement disorders and transient recurrent laryngeal nerve palsies is not changed.     

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.     

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.     

Evaluation of Intraoperative Recurrent Nerve Monitoring in Thyroid Surgery

Surgical exposure of the recurrent laryngeal nerve decreases the incidence of nerve injuries during thyroid surgery. Intraoperative neuromonitoring was introduced to facilitate identification and protection of the recurrent laryngeal nerve. Between February 1996 and June 2002 a total of 288 patients underwent thyroid surgery with intraoperative identification and intraoperative neuromonitoring of the recurrent laryngeal nerve. The overall incidences of permanent and transient recurrent nerve palsy (considered as a percentage of the nerves at risk) were 1.4% and 8.7%, respectively. Results were stratified in benign, malignant, and recurrent thyroid disease. Intraoperative function testing revealed a positive predictive value of 33% and negative predictive value of 99%. We concluded that the incidence of recurrent nerve lesions in benign, malignant, and recurrent thyroid disease was not lowered by the use of intraoperative neuromonitoring. Although an intact nerve can be verified by the neuromonitoring, the loss of nerve function cannot be reliably identified.     

Reoperative surgery for thyroid disease

Background and aims Reoperative surgery for thyroid disease is rare. However, it is sometimes indicated for nodular recurrence after partial surgery for initially benign thyroid disease or for a completion total thyroidectomy when a final diagnosis of well-differentiated thyroid cancer (WDTC) is confirmed on a permanent section of a partially removed thyroid gland. This surgery can expose the patient to postoperative complications such as recurrent laryngeal nerve (RLN) palsy or hypoparathyroidism. The aims of our study were to describe the population subjected to reoperative thyroid surgery and to evaluate postoperative morbidity to find the risk factor. Patients and methods The present study is a retrospective analysis of our experience with completion thyroidectomy: 685 consecutive patients underwent this procedure in a 14-year period, for a recurrent uninodular (85 patients) or multinodular (333 patients) goiter, recurrent thyrotoxicosis (42 patients), or a completion thyroidectomy for WDTC after partial resection of the thyroid gland (225 patients). The operative technique was standardized with identification of the RLN and parathyroid glands before removal of the thyroid gland. l-Thyroxin treatment was started the day after surgery. Postoperative rates of suffocating hematoma, wound infection, RLN palsy, hypoparathyroidism, and persistence or recurrence of hyperthyroidism were studied and compared to the same parameters in patients who underwent primary bilateral thyroid gland resection during the same period. Results The transient morbidity rate was 8%, with 5% hypoparathyroidism, 1.2% RLN palsy, 0.9% suffocating hematoma, and 0.2% wound infection. These results were higher than those from cases of primary thyroid resection for bilateral disease. Within the secondary surgery group, postoperative complications depended on the mean weight of the resected thyroid gland, hyperthyroidism, and the bilaterality of thyroid exploration during the previous surgery. The permanent morbidity rate was 3.8%, including 1.5% RLN palsy and 2.5% hypoparathyroidism. Permanent complication rates were higher than those for primary thyroid resection. Incidental carcinoma was found in 92 patients (13%): 10% (42 of 418) in patients with recurrent euthyroid nodular disease, 7% (3 of 42) in patients with recurrent hyperthyroidism, and 21% (47 of 225) in patients who underwent a completion thyroidectomy for cancer. Conclusion Because reoperative thyroid surgery can lead to potential complications, especially permanent RLN palsy or hypoparathyroidism, it should be reserved for patients who need it. The importance of respecting specific technical rules should be emphasized.     

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。     

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.     

Intraoperative Neuromonitoring for Surgical Training in Thyroid Surgery: Its Routine Use Allows a Safe Operation Instead of Lack of Experienced Mentoring

Background

The aim of the present study was to evaluate the influence of intraoperative neuromonitoring (NM) on surgical training. The results of thyroidectomy performed by inexperienced surgeons under the supervision of a consultant surgeon without intraoperative neuromonitoring (ioNM) were compared to those of the operations performed without experienced assistance but under neuromonitoring control.

Materials and methods

The study included the thyroid operations performed in our Department between 2005 and 2012. Among them, residents or fellows performed 1,116 procedures. Seven hundred sixty-five operations were conducted without neuromonitoring (NV group) and 351 with NM group. In the NV group 375 unilateral and 390 bilateral operations were performed. In the NM group 149 unilateral and 202 bilateral operations were performed. Primary end point of the study was the incidence of postoperative recurrent laryngeal nerve palsy. A secondary end point was the impact of ioNM on operating time and operative strategy.

Results

The incidence of recurrent laryngeal nerve (RLN) palsy was 2.6 % in the NV group and 2.7 % in the NM group [p = ns]. One case of bilateral RLN palsy was observed in the NV group. The operative time was longer in the NM group for both lobectomy and total thyroidectomy (50 vs. 56 min and 76 vs. 81 min, respectively; p < 0.05).

Conclusions

The routine use of intermittent intraoperative neuromonitoring during thyroid operations does not reduce the incidence of RLN palsy. Nevertheless, it allows inexperienced surgeons to perform a safe operation with a complication rate comparable to that obtained under supervision of an experienced surgeon. Moreover, ioNM could avoid the unfortunate occurrence of a bilateral RLN palsy.     

Recurrent laryngeal nerve injury in thyroid surgery: a review

Recurrent laryngeal nerve palsy (RLNP) is an important and potentially catastrophic complication of thyroid surgery. Permanent RLNP occurs in 0.3–3% of cases, with transient palsies in 5–8%. A literature review and analysis of recent data regarding RLNP in thyroid surgery was performed, with particular focus on the identification of high‐risk patients, the role of intraoperative identification and dissection of the nerve, and the role of intraoperative neuromonitoring (IONM) and optimal perioperative nerve assessment. In conjunction with the review, data from the Monash University/Alfred Hospital Endocrine Surgery Unit between January 2007 and October 2011 were retrospectively analysed, including 3736 consecutive nerves at risk (NAR). The current literature and our data confirm that patients undergoing re‐operative thyroid surgery and thyroid surgery for malignancies are at increased risk of RLNP. Intraoperative visualization and capsular dissection of the RLN remain the gold standard for intraoperative care during thyroid surgery for reducing RLNP risk. IONM should not be used as the sole mechanism for identifying and preserving the nerve, although it can be used to aid in the identification and dissection of the nerve, and may aid in nerve protection in high‐risk cases including cancer surgery and re‐operative surgery.     

Thyroid Surgery and the Usefulness of Intraoperative Neuromonitoring,a Single Center Study

Purpose/Aim of study: To compare the use of intraoperative neuromonitoring (IONM) versus visualization of the recurrent laryngeal nerve (RLN) alone in thyroid surgery with regard to incidence in postoperative RLN injury and operation time. Materials and Methods: This retrospective cohort study was performed in the Amphia Hospital, the Netherlands. All thyroid gland operations were collected from September 2009 to October 2012. For each case we recorded the patient characteristics, indication for surgery, intraoperative data, complications, results of pathological evaluation, and consultation of a ENT-surgeon. Research of current literature and statistical analysis was performed. Results: In total, 147 patients were included and classified into an IONM and non-IONM group. Both groups were similar in demographical aspects and indications for surgery. In total, we had 170 nerves at risk (NAR). In both groups, there were 85 (50%) NAR. Overall injury to the RLN was 6%. A statistical significant decrease of permanent RLN injuries was noticed in the IONM group compared to the non-IONM group (n = 0 vs n = 6; p = .044). In transient RLN injury, no difference was noticed (n = 2 vs n = 2). Operation time with or without IONM was not significantly different for hemithyroidectomies, neither for total thyroidectomies. Conclusion: IONM is a useful tool as an adjunct in thyroid surgery to prevent RLN injury. A statistical significant decrease in permanent RLN injury with the use of IONM was found, but it did not significantly decrease time of operation.     

Rolle der totalen Thyreoidektomie im primären Therapiekonzept der benignen Knotenstruma

INTRODUCTION: After subtotal resection of multinodular goiter, rates of up to 40% are reported for recurrent goiter in the long-term follow-up. Because of the increased morbidity of surgery for recurrent goiter, this study evaluated the preconditions that would justify total thyroidectomy as part of the primary therapy concept for benign multinodular goiter. MATERIAL AND METHODS: The Quality Assurance Study of Benign and Malignant Goiter covering the period from 1 January to 31 December 1998 assessed 5195 patients treated for benign goiter by primary bilateral resection. With respect to the extent of resection three groups were analyzed: bilateral subtotal resection (ST+ST, n=4580), subtotal resection with contralateral lobectomy (ST+HT, n=527), and total thyroidectomy (TT, n=88). RESULTS: The age of the patients was significantly higher (60.3 years) in the TT group than in the ST+ST (52.5 years) and ST+HT (55.6 years) groups. ASA classification grades III and IV were significantly more frequent in the TT group. The postoperative morbidity increased with the extent of resection. The rate of permanent recurrent laryngeal nerve (RLN) palsy was 0.8% for ST+ST, 1.4% for ST+HT, and 2.3% for TT and of permanent hypoparathyroidism 1.5% for ST+ST, 2.8% for ST+HT, and 12.5% for TT. Multivariate analysis showed that the extent of resection significantly increased the risk of RLN palsy (transient RR 0.5, permanent RR 0.4) and hypoparathyroidism (transient RR 0.2,permanent RR 0.08). The surgeon's experience (RR 0.6) and identification of the RLN (RR 0.5) reduced the risk of permanent RLN palsy. Additionally, the development of permanent hypoparathyroidism was reduced if at least two parathyroid glands (RR 0.4) were identified. CONCLUSION: Total thyroidectomy is associated with an increased rate of RLN palsies and hypoparathyroidism in comparison to less extensive thyroid surgery. In the hands of well-trained surgeons using an appropriate intraoperative technique, primary thyroidectomy is justified if the patient has an increased risk of recurrent goiter. Due to the increased postoperative morbidity after total thyroidectomy, subtotal thyroid resection based on the morphologic changes in the thyroid gland is still recommended as the standard treatment regimen for multinodular goiter.     

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.     

Intraoperative Neuromonitoring does not Reduce the Incidence of Recurrent Laryngeal Nerve Palsy in Thyroid Reoperations: Results of a Retrospective Comparative Analysis

Purpose  

Recurrent laryngeal nerve (RLN) palsy is the major concern of reoperative thyroid surgery, and the introduction of neuromonitoring could reduce the rate of this complication. The present study is a retrospective analysis of the experience with completion thyroidectomy with and without neuromonitoring in a referral center.     

�����񾭼�⼼���ڸ��Ӽ�״�������е�Ӧ��

??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.     

First experiences in intraoperative neurostimulation of the recurrent laryngeal nerve during thyroid surgery of children and adolescents

Background: Intraoperative neurostimulation of the recurrent laryngeal nerve may reduce nerve palsy during thyroid surgery and is well established in adults. No data regarding the value of neuromonitoring during thyroid surgery in children have been available. Methods: In a retrospective study, the authors analyzed all children who underwent surgery in our department since 1995. Neurostimulation was performed as electromyography of the vocal muscle using an electrical stimulation electrode for identification of the recurrent nerve. Results: The authors performed thyroid resections in 97 children (mean, 11.1 years), 75 because of thyroid carcinoma. The recurrent nerve was identified in each patient. The neuromonitoring was used in 53 patients. Postoperatively, one temporary nerve palsy was identified in this group (1.89%). In the group of 44 nonstimulated patients, 2 temporary (4.55%) and one permanent nerve dysfunctions (2.27%) occurred. In all stimulated patients, the results of intraoperative neurostimulation were identical with the postoperative function of the vocal cords. Conclusions: The intraoperative neurostimulation of the recurrent laryngeal nerve is a safe and reliable procedure in children and adolescents. It may reduce nerve damage during thyroid surgery. The neuromonitoring of the recurrent nerve is of high prediction for the postoperative function of the vocal cords. J Pediatr Surg 37:1414-1418.