Comparison of intraoperative neural monitoring between endoscopic transoral and bilateral axillo-breast approach thyroidectomy

BACKGROUND

The use of intraoperative neuromonitoring (IONM) during endoscopic thyroidectomy has not been fully explored, with limited studies focusing solely on the recurrent laryngeal nerve (RLN) and neglecting the external branch of the superior laryngeal nerve (EBSLN). This study aimed to compare the effectiveness of IONM in two endoscopic thyroidectomy techniques, namely the transoral and bilateral axillo-breast approach (BABA).

METHODS

We retrospectively reviewed patients who underwent endoscopic thyroidectomy with IONM and compared the outcomes between those who underwent different surgical techniques (transoral or BABA). We recorded the detection method and identification rate of the EBSLN and RLN, along with the amplitude and latency of the evoked potential.

RESULTS

We monitored 98 nerves at risk (NAR) from 74 patients (60 and 38 in the transoral and BABA groups, respectively). Almost all EBSLNs were identified using electromyography (EMG) signals and/or cricothyroid muscle twitches, except for one patient in the transoral group who developed EBSLN palsy. Patients in the transoral group were more likely to have the sternothyroid muscle divided (75.0% vs. 15.8%, p < 0.001) and had a lower rate of visual recognition of the EBSLN fibers (10.0% vs. 31.6%, p = 0.007) than did those in the BABA group. All RLNs were identified in both groups; however, patients in the BABA group had a relatively higher rate of post-dissection amplitude reduction > 50% (15.8% vs. 5.0%, p = 0.072), and one patient had transient RLN palsy.

CONCLUSIONS

Both the EBSLN and RLN could be adequately identified and monitored during endoscopic transoral and BABA thyroidectomies using IONM.

The learning curve and safety of continuous intraoperative vagus nerve monitoring in thyroid surgery

INTRODUCTION

Continuous intraoperative nerve monitoring allows for continuous feedback on the integrity of the recurrent laryngeal nerve (RLN) and the quality of its induced myogenic potential. The aims of this study were to assess the time requirements and risks associated with vagus nerve electrode placement when learning the technique.

METHODS

This is a prospective observational study carried out in a single otolaryngology department at the start of a trainee's placement. A total of 40 vagus nerve dissections in 31 consecutive operations (22 hemithyroidectomies, 9 total thyroidectomies) using automatic periodic stimulation (APS, Medtronic) are included. Of the electrode placements, 10 were performed by the trainer and 30 by the trainee. The time required for each surgical step and complications relating to vagus nerve dissection were recorded.

RESULTS

The average (median+IQR) total additional time attributable to vagus nerve dissection, electrode placement and baseline electromyogenic assessment was 3.1mins (2.5-3.3) for the trainer and 4.8mins (4.1-5.3) for the trainee (p<0.0001). There was a downward trend in time requirement for the trainee (not statistically significant, p=0.080). Total operative time was 38min (35-45) for hemithyroidectomy and 56min (53-62) for total thyroidectomy. There was a mix of benign (74%) and malignant (26%) histology, no intraoperative complications relating to autonomic dysfunction and one (2.5%) transient nerve palsy.

CONCLUSIONS

Operative time attributable to vagus nerve electrode placement is short and the procedure is easy to learn. Appropriate surgical technique and careful anaesthetic considerations allow monitoring to be performed safely, and may reduce the rate of RLN palsy.

Transcutaneous Laryngeal Ultrasonography for Assessing Vocal Cord Twitch Response in Thyroid Operation during Predissection Vagus Nerve Stimulation

BACKGROUND

In this study, we aimed to report our experience with the use of intraoperative transcutaneous laryngeal ultrasonography (TLUSG) to evaluate the vocal cord twitch response during predissection vagus nerve stimulation in thyroid surgeries and examine the reliability of this technique when compared with that of laryngeal twitch palpation (LTP).

STUDY DESIGN

The prospective data collection of consecutive patients who underwent open thyroidectomy with intraoperative neuromonitoring (IONM) was reviewed retrospectively. We recorded the electromyographic activity and assessed the vocal cord twitch response on LTP, TLUSG. We compared the accessibility, sensitivity, and specificity of the techniques.

RESULTS

A total of 110 patients (38 men and 72 women) with 134 nerves at risk were enrolled. The vocal cord was assessable by TLUSG in 103 (93.6%) patients and by LTP in 64 (59.1%) patients. Two patients showed negative predissection IONM signal but positive on TLUSG and the presence of laryngeal twitch response confirmed by laryngoscopy. Fourteen patients showed positive IONM signals and presence of the vocal cord twitch response on TLUSG but not on LTP. The sensitivity and specificity were 70.21% and 100%, respectively, for LTP, and those both were 100% for TLUSG. For patients who could be assessed using both techniques, TLUSG had better accuracy than LTP (100% vs 80.33%, p = 0.0005).

CONCLUSIONS

The innovative intraoperative application of TLUSG is better for evaluating the laryngeal twitch response than LTP. This technique provides practical troubleshooting guidance for patients with no IONM signals during predissection vagus nerve stimulation.

The effectiveness and safety of prophylactic central neck dissection in clinically node-negative papillary thyroid carcinoma patients: A meta-analysis

OBJECTIVE

This meta-analysis was performed to evaluate the effectiveness and safety of prophylactic central neck dissection (PCND) in patients with clinically node-negative (cN0) papillary thyroid carcinoma.

MATERIALS AND METHODS

A meta-analysis of the literature was performed using the key words "papillary thyroid carcinomas" and "lymph node ecisions" for searches of electronic databases. Complications such as transient hypocalcemia, permanent hypocalcemia, transient and permanent hypoparathyroidism, transient and permanent vocal cord paralysis, transient recurrent and permanent recurrent laryngeal nerve injury, and local recurrence were pooled by meta-analysis. Stata17.0 was used to carry out the meta-analysis.

RESULTS

Data were extracted from 15 studies. In the present review, the group of patients who had total thyroidectomy (TT) with PCND had a lower local recurrence than the group with TT alone (OR 0.22, 95% CI 0.10-0.45, P = 0.000), whereas the incidence of permanent hypocalcemia (OR 4.24, 95% CI 1.05-17.22, P = 0.043) and transient hypoparathyroidism (OR 2.14, 95% CI 1.34-3.42, P =0.001) were higher. No significant differences were recorded in the incidence of other complications: transient hypocalcemia (OR 2.24, 95% CI 0.77-6.51, P = 0.138), permanent hypoparathyroidism (OR 1.70, 95% CI 0.89-3.27, P = 0.111), transient vocal cord paralysis (OR 1.48, 95% CI 0.78-2.83, P = 0.231), permanent vocal cord paralysis (OR 1.44, 95% CI 0.53-3.94, P = 0.477), transient recurrent laryngeal nerve injury (OR 1.47, 95% CI 0.93-2.32, P = 0.102) and permanent recurrent laryngeal nerve injury (OR 1.24, 95% CI 0.56-2.74, P = 0.587) between the two groups.

CONCLUSION

Compared with TT alone, TT with PCND was more effective in reducing local recurrence without increasing the risk of recurrent laryngeal nerve, thyroid and vocal cord, except for hypocalcemia and transient hypoparathyroidism. Therefore, we believe that TT with PCND should be recommended for patients with cN0 PTC.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD4202 2355078.

The value of intraoperative nerve monitoring against recurrent laryngeal nerve injury in thyroid reoperations

Reoperative thyroidectomy is challenging for surgeons because of the higher incidence of recurrent laryngeal nerve (RLN) palsy. RLN identification is the gold standard during thyroidectomy; however, it is sometimes difficult to perform thyroid reoperations. In recent years, intraoperative nerve monitoring (IONM) has gained increased acceptance, and the use of IONM can be a valuable adjunct to visual identification. The aim of this study was to evaluate the value of IONM during thyroid reoperation.A total of 109 patients who met our criteria at the Affiliated Hospital of Hangzhou Normal University from January 2010 to June 2020 were retrospectively analyzed and divided into the IONM group and the visualization-alone group (VA group) according to whether neuromonitoring was used during the operation. The patients' characteristics, perioperative data, and intraoperative information including the RLN identification, time of RLNs confirmation, operative time, intraoperative blood loss, and the rate of RLN injury were collected.Sixty-five procedures (94 RLNs at risk) were performed in the IONM group, whereas 44 (65 RLNs at risk) were in the VA group. The rate of RLN identification was 96.8% in the IONM group and 75.4% in the VA group (P < .05). The incidence of RLN injury was 5.3% in the IONM group and 13.8% in the VA group (P > .05). The incidence of surgeon-related RLN injury rate was 0% in the IONM group compared to 7.7% in the VA group (P < .05), but the tumor-related or scar-related RLN injury rate between the 2 groups were not significantly different (4.3% vs 3.1%, 1.1% vs 3.1%, P > .05).IONM in thyroid reoperation was helpful in improving the RLN identification rate and reducing the surgeon-related RLN injury rate, but was ineffective in reducing the tumor-related and scar-related RLN injury rate. In the future, multicenter prospective studies with large sample sizes may be needed to further assess the role of IONM in thyroid reoperations.

Visual identification and neuromonitoring vs. no sighting the external branch of the superior laryngeal nerve in thyroid surgery: a randomized clinical trial

To evaluate the incidence of external branch of the superior laryngeal nerve (EBSLN) injuries after thyroid surgical procedures with or without the functional and visual identification of the EBSLN before ligation at the superior thyroid pole. Patients with papillary thyroid carcinoma (PTC) enrolled from a single tertiary referral academic medical center were assigned to functional and visual identification of EBSLN group (study group) or no identification of EBSLN group (controlled group). The main outcome measures were the incidence of EBSLN injury detected by the intraoperative neuromonitoring and Voice Handicap Index-10 (VHI-10) and Impairment Index-5 (VII-5) valuation questionnaires. Postoperative complications were recorded. A total of 140 (50.4%) patients were enrolled in study group and 138 (49.6%) in controlled group. In the study group, 110 (39.3%) EBSLNs were direct visual recognized and 170 (60.7%) nerves were visually identified with the help of neuromonitoring. Three patients in the study group and two patients in the controlled group were diagnosed with vocal cord paralysis. Six (4.4%) patients in the identification group and 37 (27.2%) patients in the no identification group presented no response from the stimulation of sternothyroid-laryngeal triangle. The VII-5 scores of the study group were significantly higher than those of the controlled group at one and three months postoperatively (P = 0.024 and P = 0.034). With significant lower scores of VII-5 and VHI-10, functional and visual identification of EBSLN might be necessary during thyroid surgery to protect the structural integrity and motor activity of the nerve.

New Developments in Anterior Laryngeal Recording Technique During Neuromonitored Thyroid and Parathyroid Surgery

A recurrent laryngeal nerve (RLN) injury resulting in vocal fold paralysis and dysphonia remains a major source of morbidity after thyroid and parathyroid surgeries. Intraoperative neural monitoring (IONM) is increasingly accepted as an adjunct to the standard practice of visual RLN identification. Endotracheal tube (ET) surface recording electrode systems are now widely used for IONM; however, the major limitation of the clinical use of ET-based surface electrodes is the need to maintain constant contact between the electrodes and vocal folds during surgery to obtain a high-quality recording. An ET that is malpositioned during intubation or displaced during surgical manipulation can cause a false decrease or loss of electromyography (EMG) signal. Since it may be difficult to distinguish from an EMG change caused by a true RLN injury, a false loss or decrease in EMG signal may contribute to inappropriate surgical decision making. Therefore, researchers have investigated alternative electrode systems that circumvent common causes of poor accuracy in ET-based neuromonitoring. Recent experimental and clinical studies have confirmed the hypothesis that needle or adhesive surface recording electrodes attached to the thyroid cartilage (transcartilage and percutaneous recording) or attached to the overlying neck skin (transcutaneous recording) can provide functionality similar to that of ET-based electrodes, and these recording methods enable access to the EMG response of the vocalis muscle that originates from the inner surface of the thyroid cartilage. Studies also indicate that, during surgical manipulation of the trachea, transcartilage, percutaneous, and transcutaneous anterior laryngeal (AL) recording electrodes could be more stable than ET-based surface electrodes and could be equally accurate in depicting RLN stress during IONM. These findings show that these AL electrodes have potential applications in future designs of recording electrodes and support the use of IONM as a high-quality quantitative tool in thyroid and parathyroid surgery. This article reviews the major recent developments of newly emerging transcartilage, percutaneous, and transcutaneous AL recording techniques used in IONM and evaluates their contribution to improved voice outcomes in modern thyroid surgery.

Continuous Intraoperative Nerve Monitoring in Thyroid Surgery: Can Amplitude Be a Standardized Parameter?

The objective of this study is to evaluate electromyographic waveforms related to vagus monitoring. We collected data from patients undergoing thyroidectomy with CIONM, regardless of vocal cord response amplitude initially measured. We divided data of 193 nerves into three groups, according to initial amplitude value: ≥500 µV (Group 1,110 pt.), between 100 and 500 µV (Group 2, 79 pt.), and <100 µV (Group 3, 4 pt.). ROC curve showed a high diagnostic accuracy of final amplitude absolute value in vocal cord paralysis detection in both groups (89 and 86%). An increase of vocal cord paralysis risk was associated with progressive amplitude reduction (Group 1: OR=1.05, CI=1.02-1.09, p=0.001; Group 2: OR=1.05, CI=1.02-1.08, p=0.002). Cut-off values for amplitude reduction with optimal sensitivity and specificity were -77% in Group 1 and -15% in Group 2. In Group 3 signals showed an amplitude <100 µV for all monitoring, with no loss of a recognizable signal and normal postoperative cordal functionality. The use of a strict amplitude signal cut-off value ≥500 µV could be too restrictive. Also, signal with baseline amplitude <500 µV may be considered equally adequate. Setting the alarm for a reduction of 77% in patients with initial amplitude ≥500 µV and of 15% for those <500 µV could make monitoring safe and an effective aid for surgeons. In conclusion, there are cases in which initial amplitude is lower than that considered as adequate by current literature but with well recognizable and stable EMG waveforms. How those cases should be approached and what should the surgeon's attitude be are a matter of discussion.

Neurophysiological monitoring of the laryngeal adductor reflex during cerebellar-pontine angle and brainstem surgery

OBJECTIVE

To correlate intraoperative changes of the laryngeal adductor reflex (LAR), alone or in combination with corticobulbar motor evoked potential of vocal muscles (vocal-CoMEPs), with postoperative laryngeal function after posterior fossa and brainstem surgery.

METHODS

We monitored 53 patients during cerebellar-pontine angle and brainstem surgeries. Vocal-CoMEPs and LAR were recorded from an endotracheal tube with imbedded electrodes or hook-wires electrodes. A LAR significant change (LAR-SC) defined as ≥ 50% amplitude decrement or loss, was classified as either transient or permanent injury to the vagus or medullary pathways by the end of the surgery.

RESULTS

All patients with permanent LAR loss (n = 5) or LAR-SC (n = 3), developed postoperative laryngeal dysfunction such as aspiration/pneumonia and permanent swallowing deficits (5.6%). Vocal-CoMEP findings refined postoperative vocal motor dysfunction. All seven patients with transient LAR-SC or loss, reverted by changing the surgical approach, did not present permanent deficits.

CONCLUSIONS

Permanent LAR-SCs or loss correlated with postoperative laryngeal dysfunction and predicted motor and sensory dysfunction of the vagus nerve and reflexive medullary pathways. In contrast, a LAR-SC or loss, averted by a timely surgical adjustment, prevented irreversible damage.

SIGNIFICANCE

Monitoring of the LAR, with vocal-CoMEPs, may enhance safety to resect complex posterior fossa and brainstem lesions.

To explore the risk factors and preventive measures affecting the treatment of retrosternal goiter: An observational study

The definition of substernal goiter (SG) is based on variable criteria, leading to considerable variations in the reported incidence (from 0.2% to 45%). The peri- and postoperative complications are higher in total thyroidectomy (TT) for SG than that for cervical goiter. This study aimed to evaluate the preoperative risk factors associated with postoperative complications.From 2002 to 2014, 142 (8.5%; 98 women and 44 men) of the 1690 patients who underwent TT had a SG. We retrospectively evaluated the following parameters: sex, age, histology, pre- and retro-vascular position, recurrence, and extension beyond the carina. These parameters were then related to the postoperative complications: seroma/hematoma, transient and permanent hypocalcemia, transient and permanent laryngeal nerve palsy, and the length of surgery. The results were further compared with a control group of 120 patients operated on in the same period with TT for cervical goiter (CG).Statistical analysis (Student t test and Fisher exact test) indicated an association between recurrence and extension beyond the carina with all postoperative complications. The group that underwent TT of SG showed a statistically significant higher risk for transient hypocalcemia (relative risk = 1.767 with 95% confidence interval: 1.131-2.7605, P = .0124, and need to treat = 7.1) and a trend toward significance for transient recurrent laryngeal nerve palsy (relative risk = 6.7806 with 95% confidence interval: 0.8577-53.2898, P = .0696, and need to treat = 20.8) compared with the group that underwent TT of cervical goiter. The major risk factors associated with postoperative complications are recurrence and extension beyond the carina.TT is the procedure to perform in SG even if the incidence of complications is higher than cervical goiters. The major risk factors associated with postoperative complications are recurrence and extension beyond the carina.

Routine Preoperative Laryngoscopy for Thyroid Surgery Is Not Necessary Without Risk Factors

Background: Routine preoperative vocal cord (VC) assessment with laryngoscopy in patients undergoing thyroidectomy allows clear documentation of baseline VC function, aids in surgical planning in patients with palsies, and facilitates interpretation of intraoperative neuromonitoring (IONM) findings. We aimed to determine the incidence of preoperative vocal cord palsy (VCP); to evaluate the associated risk factors for preoperative VCP; and to calculate the cost-savings potential of implementing a selective approach. Methods: Patients with a pre-thyroidectomy VC assessment by fiberoptic laryngoscopy were retrospectively recruited from the Monash University Endocrine Surgery Unit database from 2000 to 2018. Cases with preoperative VCP were reviewed for potential contributing factors and compared with a non-palsy cohort. Results: Of the 5987 patients who had preoperative laryngoscopy, VCP was documented in 41 (0.68%) patients. Four clinical parameters were found to be potential indicators of VCP, including: age (p < 0.001), nodule ≥3.5 cm recorded on ultrasound imaging (p = 0.01), presence of voice symptoms (p < 0.001), and previous neck surgery (p < 0.001). Malignant cytology (p = 0.5) and exposure to head and neck irradiation were not different between the groups. Utilizing these risk factors, 2354 (39%) patients had at least one feature that may raise suspicion for preoperative VCP. By performing preoperative laryngoscopy only on this subset of patients, the potential cost savings exceeds 400 Australian Dollars per patient. Conclusions: Using this large dataset, we have established that a VCP is rare in the absence of a large nodule, hoarseness, or previous neck surgery. Therefore, in the era of IONM, we support a selective approach to preoperative laryngoscopy by using the aforementioned criteria.

Utility of continuous intraoperative neural monitoring in thyroid surgery in a low volume centre

This retrospective study, of a single surgeon's experience, evaluates the role of intraoperative neuromonitoring (IONM) for total thyroidectomy, in a low-volume district general hospital. 128 patients with normal preoperative vocal fold function underwent thyroid surgery with routine use of nerve monitoring. Patients were followed for 6 months after surgery, and postoperative Romanerve function was determined by fiberoptic laryngoscopy. One (0,8%) patient was found to have a unilateral vocal fold paralysis, but after 6 months this patient had regained vocal fold motion. The technique of intraoperative neuromonitoring in thyroid surgery is safe and reliable in excluding postoperative recurrent laryngeal nerve palsy; it has high accuracy, specificity, sensitivity and negative predictive value. Neuromonitoring is useful to identify the recurrent laryngeal nerve and it can be a useful adjunctive technique for reassuring surgeons of the functional integrity of the nerve. Its application can be particularly recommended for low-volume thyroid operation centres.

Surgical management of the compromised recurrent laryngeal nerve in thyroid cancer

Surgical management of thyroid cancer requires careful consideration of the recurrent laryngeal nerve and its impact on glottic function. Management of the compromised recurrent laryngeal nerve is a complex task, requiring synthesis of multiple elements. The surgeon must have an appreciation for preoperative recurrent laryngeal nerve function, intraoperative anatomic and electromyographic information, disease characteristics, and relevant patient factors. Preoperative clinical evaluation including preoperative laryngoscopy and assessment of recurrent laryngeal nerve risk is essential to formulating a surgical plan and providing appropriate patient counseling. Intraoperative neuromonitoring information has significant implications for surgical management of the injured or invaded recurrent laryngeal nerve and informs strategy with respect to staging of bilateral surgery. Disease characteristics and patient-related factors, including patient preference, must be considered with intraoperative decision-making. Multidisciplinary discussion and patient communication are essential for effective management and successful surgical outcome.

Diverse Anatomical Configuration Of Recurrent Laryngeal Nerve In Relation To Inferior Thyroid Artery, An Experience With 51 Thyroidectomies

BACKGROUND

Objective of the study is to elaborate the anatomical variants of recurrent laryngeal nerve in relation to inferior thyroid artery, encountered during thyroidectomy operation. It is descriptive, case series, conducted at the Department of Ear Nose & Throat, Combined Military Hospital, Abbottabad. The study was conducted from January 2016 to September 2017.

METHODS

Fifty-one patients underwent extra-capsular thyroidectomy in general anaesthesia. The dissection was carried out in a standard way in all patients. Recurrent laryngeal nerves were identified and exposed in every patient, and their anatomical relations were recorded in database.

RESULTS

Recurrent laryngeal nerve was seen over riding the ramification of inferior thyroid artery in majority of left sided dissected specimen, however on the right side the principal nerve was found to be ascending through the branches of inferior thyroid artery..

CONCLUSIONS

Iatrogenic vocal cord paralysis has sinister implication on quality of life of the patient undergoing thyroidectomy. Anatomic variants of recurrent laryngeal nerve are well known and frequent. The disastrous outcome of inadvertent recurrent laryngeal nerve trauma can be adequately prevented by thoroughly knowing its anatomical variants, and intra-operatively identifying and exposing the principal nerves.

Routine Intraoperative Neuromonitoring of the Recurrent Laryngeal Nerve to Facilitate Complete Resection and Ensure Safety in Thyroid Cancer Surgery

Routine use of intraoperative neuromonitoring (IONM) in thyroid cancer surgery is controversial. We aimed to investigate whether it improves the completeness of thyroidectomy and ensures safety. This retrospective study included 380 thyroid cancer patients who underwent thyroidectomy, by one surgeon, between July 2006 and November 2015. Patients were grouped according to the surgeon's adaptation of IONM, as follows: none (period 1; n = 92), early (period 2; n = 141), and late (period 3; n = 147). The operative time and rates of vocal cord palsy were determined. Surgical completeness was assessed by technetium-99m imaging of the thyroid remnant and serum thyroglobulin measurement before ablation. The rate of recurrent laryngeal nerve (RLN) palsy showed a decreasing trend over time. No permanent RLN palsies occurred in nerves not invaded by tumor after routine IONM was introduced. Technetium-99m uptake (periods 1-3, 0.62 vs 0.32 vs 0.20; P < 0.01) and thyroglobulin levels (periods 1 and 2, 37.93 vs 8.98 ng/mL, respectively; P = 0.034; period 3, 9.10 ng/mL) progressively decreased. The mean thyroglobulin level dropped significantly after introduction of routine IONM. We conclude that routine IONM during thyroid cancer surgery improves surgical completeness and might prevent permanent RLN palsy over time.

[Hybrid Treatment for Aortic Arch Aneurysm Concomitant with Right Subclavian Artery Aneurysm]

A 78-year-old man was hospitalized for aortic arch aneurysm concomitant with right subclavian artery aneurysm. Maximum diameter of each aneurysm was 65 mm and 40 mm, respectively. Both aneurysms clearly needed to be treated. However, simultaneous surgery of total arch replacement (TAR) and right subclavian artery grafting carries both technical difficulty of surgical exposure and considerable risk of bilateral recurrent nerve palsy. Thus, to avoid these serious problems, we chose hybrid treatment. TAR was performed as the 1st procedure, followed by stent graft placement to right subclavian artery aneurysm. At the 1st procedure, an 8 mm graft was anastomosed to right common carotid artery in end to side fashion. This was used for cerebral perfusion, and after that, another end of this graft was anastomosed to a branch of quadrant graft which was anastomosed to brachiocephalic artery. Then, right common carotid artery was ligated at proximal portion to create a proximal landing zone. As the 2nd procedure, excluder leg was deployed via right axillary artery without difficulty. He was discharged with uneventful postoperative course.

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.

[Intraoperative Nerve Monitoring System during Esophagectomy to Prevent Recurrent Laryngeal Nerve Palsy]

Recurrent laryngeal nerve (RLN) palsy can result in motility disorders of the vocal cord muscles and/or fatal respiratory complications. Procedures aimed at checking for intraoperative RLN injuries have not been established. Intraoperative nerve monitoring( IONM) informs electromyographic activity of the vocal cord muscles to a surgeon by visual and aural signals. In this chapter, we introduce methods for using IONM during esophageal cancer surgery. Since we introduced IONM, several cases in which surgeons have had difficulty visually identifying the RLN have been reported. In those cases, the RLN was definitively identified using IONM. IONM can be used safely, simply, and promptly during esophageal cancer surgery for identifying the RLN to prevent and predict postoperative RLN palsy. This useful device is possible to improve the safety of the surgical procedures subsequently.

IONM and minimally invasive videoassisted thyroidectomy

BACKGROUND

We know that benefits of MIVAT are related to a better cosmetic result and lower post-operative pain in comparison to CT. The incidence of nerve cold palsy is related to a correct identification of the recurrent laringeal nerve (RLN) as standard procedure in thyroid surgery. From September 2014 we have introduced the use of intraoperative neural monitoring(I-IONM) in all thyroidectomies in the Unit of General Surgery of University Hospital of Parma, including in MIVAT.

PATIENTS AND METHODS

We have considered all patients treated from September 2014 to September 2017 for thyroid diseases using MIVAT and IONM. Intermittent neuromonitoring with NIM-3.0 equipment (Medtronic, Jacksonville, FL, USA) was used during all operations. We have recorded all data about age, sex, diagnosis, surgical time, i-IONM signal, postoperative pain, postoperative hypocalcemia after 24 hours, haematoma and vocal cord palsy. The mean hospital stay was collected from surgical procedure to hospital discharge. We have considered vocal dysfunctions that persist six months after surgery as permanent.

RESULTS

From September 2014 to September 2017 we treated consecutively with both MIVAT and i-IONM 100 patients. Considering the extent of surgery, 26 pts underwent to hemithyroidectomy and 74 pts to total thyroidectomy. The mean surgical time was 61.8 minutes. In 7 cases the patients were affected by preoperative clinical dysphonia. Using I-IONM during thyroidectomy, we recorded in 5 cases (5%) a loss of signal; in two cases (2%) we experienced a temporary postoperative vocal cord palsy.

DISCUSSION

In our experience the use of IONM has improved the safety during thyroidectomy because precision that can be achieved by endoscopic procedures is further improved by complementary use of IONM. The costs associated to a potential reduction of medical litigation have not been investigated.

[Intraoperative neuromonitoring in endocrine surgery: when is it appropriate?]

The use of intraoperative neuromonitoring (IONM) in thyroid surgery has steadily increased in recent years. This technique helps to identify different nerves in and around the operation site, such as the recurrent laryngeal nerve (RLN) and the external branch of the superior laryngeal nerve. Particularly in patients who undergo a second operation or a complex procedure for malignancy, the technique's value has been demonstrated. However, in non-complex thyroid operations the risk of vocal cord paresis due to iatrogenic injury of the RLN is 0.1%. Therefore, high quality research with sufficient power to assess the effect of IONM on prevention of vocal cord paresis is scarce, and the routine use of IONM in thyroid surgery is currently not indicated.

Analyzing cost-effectiveness of neural-monitoring in recurrent laryngeal nerve recovery course in thyroid surgery

PURPOSE

The increasing use of intraoperative neural monitoring (IONM) of the recurrent laryngeal nerve (RLN) during thyroid surgery imposes an evaluation of cost-effectiveness.

METHODS

The analysis estimated the cost versus utility of different alternatives that simulate nerve injury course and the consequences for the following cohorts of patients: (1) no RLN injury, or vocal fold palsy (VCP) recovery within 1 month (2), 2 months (3), 6 months (4), and after 12 months (5). In the model applied, the average simulated cohort consisted of a young female patient, 40 years old, employed, daily voice user, who underwent elective, conventional total thyroidectomy via cervical incision using a standardized intermittent IONM technique, for an operable benign, bilateral, diffuse, multinodular, non-toxic, non-retrosternal goiter.

RESULTS

IONM was cost-ineffective when parameters such as the rates of transient vocal fold palsy (VCP) reached 38.5%. IONM was cost-effective if the rate of VCP was 33.6% at 1 month, 22.9% at 2 months, 9.8% at 6 months, and 3.8% at 12 months, independent of phono-surgery. The described scenario is cost-effective only in a high-volume setting.

CONCLUSIONS

This study used simulation economic modeling to assess clinical and cost-effectiveness utility of IONM implementation. In light of the limitations of a simulation-based study, we conclusively assumed that IONM is cost-effective for permeant RLN injuries.

Utility of intraoperative nerve monitoring in thyroid surgery: 20-year experience with 1418 cases

PURPOSE

The efficacy of intraoperative nerve monitoring is controversial in the literature. This study of a single surgeon's experience seeks to determine if the use of intraoperative nerve monitoring influences recurrent laryngeal nerve injury during thyroid surgery.

METHODS

Six hundred fifty-seven patients with normal pre-operative vocal fold function underwent thyroid surgery without the use of intraoperative nerve monitoring from September 1997 to January 2007, while 761 patients underwent thyroid surgery from February 2007 to February 2016 with routine use of nerve monitoring. Patients were followed for a minimum of 6 months after surgery, and postoperative nerve function was determined by fiberoptic laryngoscopy. A Fisher test was used to determine if nerve injury was statistically different between both groups.

RESULTS

In patients operated on without nerve monitoring, 21 patients were found to have postoperative vocal fold paralysis with nine regaining functioning. In patients operated on with nerve monitoring, 27 were found to have vocal fold dysfunction with 17 regaining function. Fisher test analysis, both with and without patients regaining function, showed no difference in nerve injury between groups (p > 0.05, p > 0.05).

CONCLUSION

Intraoperative monitoring during thyroidectomy may not prevent injury to the recurrent laryngeal nerve.

Role of intraoperative neuromonitoring of the recurrent laryngeal nerves during thyroid reoperations of recurrent goiter

Reoperations of the thyroid gland are challenging to any surgeon. Such procedures are technically difficult and involve higher risk of complications than primary procedures. Recurrent laryngeal nerve (RLN) palsy is one of such complications The aim of the study was to evaluate the effectiveness of intraoperative neuromonitoring (IONM) in preventing RLN palsy during recurrent goiter operations.

MATERIAL AND METHODS

We retrospectively analyzed the results of thyroid reoperation performed at the Department of Endocrine, General and Vascular Surgery of Medical University of Lodz in the period from January 2014 to June 2016. The study included 80 patients, who were divided into 2 groups: group A consisted of 27 patients, who had undergone surgery with the use of IONM, while group B included 53 patients, in whom RLN was identified visually. During statistical analysis we took into account the number of nerves at risk, not the number of patients. There were 47 nerves at risk In group A and 86 in group B. We analyzed whether application of IONM had any effect on the frequency of RLN palsy and procedure duration.

RESULTS

The frequency of RLN palsy was 10.64% (5/47) in group A and 15.12% (13/86) in group B (no statistical significance, p=0,47). Mean operation time was shorter in group B 71.29 ± 17.125 minutes vs. 75.75 ± 17.94 minutes in group A (no statistical significance, p=0,377).

CONCLUSION

Use of IONM did not significantly reduce the occurrence of RLN palsy and procedure duration.

The current state of intermittent intraoperative neural monitoring for prevention of recurrent laryngeal nerve injury during thyroidectomy: a PRISMA-compliant systematic review of overlapping meta-analyses

PURPOSE

Recurrent laryngeal nerve (RLN) injury is one of the most common and detrimental complications following thyroidectomy. Intermittent intraoperative nerve monitoring (I-IONM) has been proposed to reduce prevalence of RLN injury following thyroidectomy and has gained increasing acceptance in recent years.

METHODS

A comprehensive database search was performed, and data from eligible meta-analyses meeting the inclusion criteria were extracted. Transient, permanent, and overall RLN injuries were the primary outcome measures. Quality assessment via AMSTAR, heterogeneity appraisal, and selection of best evidence was performed via a Jadad algorithm.

RESULTS

Eight meta-analyses met the inclusion criteria. Meta-analyses included between 6 and 23 original studies each. Via utilization of the Jadad algorithm, the selection of best evidence resulted in choosing of Pisanu et al. (Surg Res 188:152-161, 2014). Five out of eight meta-analyses demonstrated non-significant (p > 0.05) RLN injury reduction with the use of I-IONM versus nerve visualization alone.

CONCLUSIONS

To date, I-IONM has not achieved a significant level of RLN injury reduction as shown by the meta-analysis conducted by Pisanu et al. (Surg Res 188:152-161, 2014). However, most recent developments of IONM technology including continuous vagal IONM and concept of staged thyroidectomy in case of loss of signal on the first side in order to prevent bilateral RLN injury may provide additional benefits which were out of the scope of this study and need to be assessed in further prospective multicenter trials.

Prevalence and patterns of intraoperative nerve monitoring for thyroidectomy

Objective

To estimate the patterns of use of intraoperative recurrent laryngeal nerve (RLN)-monitoring devices during thyroid surgery by otolaryngologists in the United States.

Methods

A questionnaire was mailed to 1685 randomly selected otolaryngologists, representing approximately half of all otolaryngologists currently practicing in the United States. Topics covered included training history and current practice setting, use and characteristics of use of RLN monitoring during thyroid surgery, as well as history of RLN injury and/or subsequent lawsuits. X 2 test was used to examine associations between monitor usage and dependent variables, and odds ratios calculated by logistic regression were used to refine the magnitude of these associations. RESULTS: A total of 685 (40.7%) of questionnaires were returned, and 81 percent (555) of respondents reported performing thyroidectomy. Of those, only 28.6 percent (159) reported using intraoperative monitoring for all cases. Respondents were 3.14 times more likely to currently use intraoperative monitoring if they used it during their training. Surgeons currently using intraoperative RLN monitoring during thyroidectomy were 41 percent less likely to report a history of permanent RLN injury. Further information about surgeon background and rationale for decisions regarding RLN monitor usage are discussed.

Conclusions

Presently, the majority of otolaryngologists in the United States do not report regular usage of RLN monitoring in their practices. Surgeon background and training, more so than surgical volume, significantly influenced the use of intraoperative RLN monitoring.

Continuous Laryngeal Nerve Integrity Monitoring During Thyroidectomy: Does it Reduce Risk of Injury?

OBJECTIVE: To determine if continuous laryngeal nerve integrity monitoring (NIM) during thyroidectomy is associated with a decreased risk of postoperative recurrent laryngeal nerve (RLN) injury.

STUDY DESIGN AND SETTING: Retrospective cohort study of 165 patients who underwent thyroidectomy at a resident teaching institution between 1999 and 2002. The control group had 120 nerves at risk (NAR) whereas the NIM group consisted of 116 NAR. Primary outcome measures included postoperative RLN paralysis, paresis, and total injury rates.

RESULTS: RLN paralysis occurred in 2.54% NAR in the control group and 0.86% in the NIM group (relative risk (RR) = 0.34, 95% confidence interval (CI95) = 0.04-3.27, P = 0.62). Temporary RLN paresis occurred in 4.24% NAR in the control group and 3.45% in the NIM group (RR = 0.9, CI95 = 0.23-3.55, P = 0.89). Total RLN injury occurred in 6.78% NAR in the control group and 4.31% in the NIM group (RR = 0.66, CI95 = 0.21-2.09, P = 0.48). When compared to all other NAR, advanced T-stage malignancy was associated with a significantly increased risk of RLN paresis (T4 RR = 9.0, CI95 = 2.56-31.67, P = 0.0006; T3+T4 RR = 7.5, CI95 = 2.17-25.86, P = 0.0001) but not paralysis. NIM did not significantly reduce the risk of RLN paresis in the advanced T-stage subset (T3+T4 RR = 0.36, CI95 = 0.04-3.0, P = 0.59).

CONCLUSION: There were no statistically significant differences in RLN paralysis, paresis, or total injury rates between control and NIM groups, even in subsets with advanced T-stage and increased baseline risk. Advanced T-stage is a significant predictor of RLN paresis in this cohort.

Prognostic value of intraoperative neural monitoring of the recurrent laryngeal nerve in thyroid surgery

Purpose

The diagnostic accuracy of intraoperative recurrent laryngeal nerve (RLN) monitoring (IONM) remains controversial. The aim of this study was to evaluate IONM diagnostic accuracy in prognostication of postoperative nerve function in thyroid surgery.

Methods

This prospective study was conducted in 2011–2013. Five hundred consenting patients qualified for total thyroidectomy with IONM (1000 nerves at risk) using NIM 3.0 Response equipment were included. Laryngoscopy was used to evaluate and follow up RLN injury. The primary outcome was diagnostic accuracy of IONM. The receiver operating characteristics (ROC) were used for evaluation of IONM diagnostic accuracy.

Results

Loss of signal (LOS) occurred in 31 cases, including 25 patients with LOS and corresponding vocal fold paresis found in postoperative laryngoscopy (2.5 %), including 20 (2.0 %) temporary and 5 (0.5 %) permanent nerve lesions. The following diagnostic accuracy values were calculated for the criterion recommended by INMSG (V2 amplitude ≤ 100 μV): sensitivity 92.0 %, specificity 99.3 %, positive predictive value (PPV) 76.7 %, and negative predictive value (NPV) 99.8 %. The ROC curve analysis allowed for calculation of the most optimal criterion in prognostication of postoperative vocal fold paresis, namely, V2 amplitude ≤ 189 μV. For this criterion, PPV was 77.4 %, while NPV was 99.9 %.

Conclusions

Adherence to the standardized protocol recommended by the International Neural Monitoring Study Group allows for optimizing predictive values of IONM in prognostication of postoperative RLN function. Any changes in the cutoff values for the definition of LOS only marginally improve PPV and NPV of IONM and need to be carefully assessed in multicenter studies.

Clinical Outcomes of a Team Approach to Thyroidectomy

OBJECTIVE

The aim of this study is to assess the rates of thyroidectomy complications performed by two attending surgeons operating together.

STUDY DESIGN

This is a retrospective chart review.

METHODS

This is a retrospective chart review from September 2008 through October 2013 of thyroidectomy cases performed by the head and neck team at Sanford Health. The primary intervention was the presence of two head and neck attendings during each procedure. Outcomes assessed include rates of temporary and permanent recurrent laryngeal nerve paralysis, and of permanent hypocalcemia.

RESULTS

There were 282 patients that underwent a thyroid procedure with a total of 449 at-risk nerves. There were five (1.1 percent) cases of transient vocal cord paresis. There was one case (0.22 percent) of permanent vocal cord paresis after planned nerve resection in a patient with anaplastic thyroid carcinoma. There were no other cases of permanent vocal cord paresis. Of 156 total thyroidectomy cases, there was one case of chronic hypocalcemia (0.64 percent).

CONCLUSIONS

A two-surgeon approach to thyroidectomy produces excellent functional outcomes. Further investigation into cost-effectiveness is warranted.

Ultrasound and thyroiditis in patient candidates for thyroidectomy

AIM

Thyroiditis is often associated with nodules based on the Bethesda classification system, and the presence of thyroiditis can make thyroid surgery difficult using both conventional techniques and minimally invasive videoassisted approaches (MIVAT).

METHODS

We analyzed 326 patients who underwent total thyroidectomy in 2012. We collected all data in dedicated database. The patients were divided in 4 groups: group 1 no affected by thyroiditis, group 2 affected by thyroiditis, group 3 only histological diagnosis of thyroiditis, group 4all patients affected by thyroiditis.

RESULTS

Group 1 included 201 cases, group 2 included 64 patients, group 3 included 61 patients. No statistically significant difference between group 2 and 3 about Ultrasound (US) examination. Statistically significant difference in incidence of "THYR 3-4" between group 1 and group 4. No differences in MIVAT vs. Conventional group.

CONCLUSION

US examination of the thyroid is essential for the diagnostic study of the gland also in the selection of a surgical approach. Thyroiditis is a relative contraindication to MIVAT but the experience of the endocrine surgeon is the most important factor to reduce intra and postoperative complications together a correct collaboration in multidisciplinart endocrinological team.

Evaluation of the learning curve for intraoperative neural monitoring of the recurrent laryngeal nerves in thyroid surgery

Intraoperative neuromonitoring facilitates identification of the recurrent laryngeal nerves (RLN) and allows for predicting their postoperative function. Nevertheless, the outcome of thyroid surgery monitoring is affected by both the experience of the operator and his mastering of the technique. The aim of the study was the assessment of the learning curve for intraoperative RLN neuromonitoring.

MATERIAL AND METHODS

The prospective analysis included 100 consecutive thyroid operations performed by a single surgeon during implementation of RLN neuromonitoring in a district surgical ward in Staszów. RLN neuromonitoring was performed in keeping with the recommendations of the International Neural Monitoring Study Group using a C2 NerveMonitor (Inomed, Germany). The outcomes of initial 50 procedures (group I: 08/2012-07/2013) were compared with the results of subsequent 50 operations (group II: 08/2013-07/2014). The evaluation included demographic and intraoperative data along with predictive value of the method and complications.

RESULTS

In group II as compared to group I, a significant reduction of operative time was noted (102.1 ± 19.4 vs 109.9 ± 19; p = 0.045), along with an increased percentage of identified RLNs (99% vs 89.2%; p = 0.006), a decreased percentage of correction-requiring technical errors (8% vs 24%; p = 0.029), an improved negative predictive (99% vs 89.3%; p < 0.001) and positive value (75% vs 55.6%; p < 0.001), as well as a decreased percentage of RLN injuries (3% vs 14%; p = 0.006).

CONCLUSIONS

Mastering the technique of intraoperative RLN neuromonitoring in thyroid surgery requires the surgeon to perform independently approximately 50 monitored procedures, what allows for achieving the predictive value of the method that is comparable to outcomes published by referral centers.

Intraoperative recurrent laryngeal nerve monitoring in thyroid surgery Evaluation of its use in terms of "spending review"

BACKGROUND

Intra Operative Nerve Monitoring (IONM) has been used in head and neck surgery since the 1970s. Its utilization for monitoring and protecting the recurrent laryngeal nerve, however, is a controversial subject. This paper details the use, value, and cost of this technology within a single institution.

METHODS

We conducted a retrospective chart review, analysis of surgery time with and without IONM, analysis of postoperative vocal cord function, and review of the literature

RESULTS

IONM did not reduce the operative time during total thyroidectomies in our experience. Use of IONM increased the cost of each surgery by € 450. IONM did not decrease the number of injured nerves (postoperative paresis).

CONCLUSIONS

IONM has proven to be highly useful in certain circumstances but has not been definitively proven to protect the nerve any more effectively than the gold standard of nerve visualization. In our study, the use of IONM did not reduce the time of thyroid surgery and did increase the cost. While IONM may, in special clinical circumstances such as revision and malignant thyroid surgery, increase the value of the operation, its use for every thyroid surgery does not appear to be cost effective or valuable to the patient.

Total thyroidectomy and central lymph node dissection. Experience of a referral centre for endocrine surgery

AIM

Thyroid cancer prognosis is determined by several variables, even with extremely elevated survival rate. The most debated issues are the type of thyroidectomy and extension of lymphadenectomy. Aim of the study is the analysis of benefits of level VI lymphadenectomy associated to total thyroidectomy in the treatment of thyroid cancer.

PATIENTS AND METHODS

316 total thyroidectomy with central node dissection were carried out in the Unit of Endocrine Surgery, University of Perugia. Direct parathyroid auto-implantation was carried out if damage or accidental excision occurred. High risk patients received radioiodine treatment.

RESULTS

Lymph node metastases in the VI level were observed in 42% of cases with a significant difference (p 0.0042) of positive lymph node in level VI comparing tumor larger than 1 cm vs smaller than 1 cm. No significant differences were observed when considering difference of sex, and age. Significant difference (p 0.005) was shown when considering over 45 years old male patients with tumor larger than 1 cm vs smaller ones. The 78% of patients underwent iodine ablation after surgery. Recurrence rate in these patients was 3.2%, with no significant difference compared to not treated patients. Bilateral temporary recurrent nerves palsy were observed in 0.6% of cases, unilateral temporary recurrent nerves palsy in 3.4%, unilateral permanent palsy in 1.5%, temporary hypoparathyroidism in 17%, permanent hypoparathyroidism in 4.4%.

CONCLUSIONS

Total thyroidectomy combined to central node dissection, even in absence of risk factors and without clinical evident nodes, is the treatment of choice offering clear indications to radioiodine ablation.

Relaxierung und elektromyographische Identifikation des N. laryngeus recurrens

INTRODUCTION

Electromyography for the identification of the recurrent laryngeal nerve is gaining ever more acceptance in thyroid surgery. Relaxation of the patient, e.g., to improve intubation conditions for anesthesia, carries a potential risk for error.

METHOD

After definite identification of the recurrent laryngeal nerve and the vagus nerve (Neurosign 100, Magstim Co., Wales), ten consecutive patients were relaxed with mivacurium and atracurium besylate at a weight-dependent ED95 dosage. After peripheral relaxation was achieved (TOF-Watch, Organon Teknika Corp., at the adductor muscle of the thumb), the signal derived via the vocal muscle was assessed acoustically in 3-min intervals by the surgeon and graphically recorded by computer (EWACS, Inomed Co.).

RESULTS

Complete peripheral relaxation was attained with mivacurium after 3-7 min and with atracurium after 7-11 min. A decrease in amplitude of the vocal muscle signal of >60% was recognized by the surgeon as a weakened signal and could be confirmed during an average duration of 13.3 min with mivacurium (maximum: 37 min) and 17.7 min with atracurium besylate (maximum: 23 min), respectively. Complete obliteration of the acoustic signal (<20% of the initial signal) occurred in three of six patients treated with mivacurium and in four of four patients treated with atracurium.

CONCLUSIONS

The accuracy of electromyography of the recurrent laryngeal nerve can be substantially impaired by the administration of relaxants. If this medication cannot be dispensed with, the surgeon must be aware of the situation. In these cases, a peripheral relaxometer should also be employed to monitor relaxation as it subsides.

Functional regeneration of recurrent laryngeal nerve injury during thyroid surgery using an asymmetrically porous nerve guide conduit in an animal model

BACKGROUND

Vocal cord paralysis (VCP) caused by recurrent laryngeal nerve (RLN) damage during thyroidectomy commonly results in serious medico-legal problems. The purpose of this study was to evaluate the usefulness of an asymmetrically porous polycaprolactone (PCL)/Pluronic F127 nerve guide conduit (NGC) for functional regeneration in a RLN injury animal model.

METHODS

A biodegradable, asymmetrically porous PCL/F127 NGC with selective permeability was fabricated for use in this study. A 10-mm segment of left RLN was resected in 28 New Zealand white rabbits, and then an asymmetrically porous NGC or a nonporous silicone tube was interposed between both stumps and securely fixed. Vocal cord mobility was endoscopically evaluated at one, four, and eight weeks postoperatively. Nerve growth through NGCs was assessed by toluidine blue staining, and thyroarytenoid (TA) muscle atrophy was evaluated by hematoxylin and eosin staining. Immunohistochemical stainings for acetylcholinesterase (AchE), anti-neurofilament (NF), and anti-S100 protein were also conducted, and transmission electron microscopy (TEM) was used to evaluate functional nerve regeneration.

RESULTS

At eight weeks postoperatively, endoscopic evaluations showed significantly better recovery from VCP in the asymmetrically porous PCL/F127 NGC group (6 of 10 rabbits) than in the silicone tube group (1 of 10 rabbits). Continued nerve growth on the damaged nerve endings was observed with time in the asymmetrically porous PCL/F127 NGC-interposed RLNs. TA muscle dimensions and AchE expressions in TA muscle were significantly greater in the asymmetrically porous PCL/F127 NGC group than in the silicone tube group. Furthermore, immunohistochemical staining revealed the expression of NF and S100 protein in the regenerated nerves in the asymmetrically porous PCL/F127 NGC group at eight weeks postoperatively, and at this time, TEM imaging showed myelinated axons in the regenerated RLNs.

CONCLUSION

The study shows that asymmetrically porous PCL/F127 NGC provides a favorable environment for RLN regeneration and that it has therapeutic potential for the regeneration of RLN damage.

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.

Systematic use of recurrent laryngeal nerve neuromonitoring changes the operative strategy in planned bilateral thyroidectomy

BACKGROUND

One of the worst complications in thyroid surgery is bilateral recurrent laryngeal nerve paralysis, which can lead to transient or definitive tracheotomy.

METHODS

We implemented a strict standard operative procedure beginning in January 2010 and modified our operative procedure. In all patients undergoing bilateral operation, we begin with the largest side or with the cancerous/suspicious side without dissecting the contralateral side. If the intraoperative neuromonitoring (IONM) signal is lost after stimulation of the vagus nerve at the end of the first side, we stop the procedure after the unilateral lobectomy, even if the recurrent nerve is anatomically intact and regardless of malignancy. If the IONM signal is lost, serial laryngoscopies are performed until recovery or definitive recurrent laryngeal nerve palsy is demonstrated. We report here our results in patients with loss of the IONM signal after lobectomy and discuss the medical implications for benign and malignant thyroid conditions.

RESULTS

Since January 2010, the operation has been stopped at the first side in 9 out of 220 planned bilateral thyroidectomies. There were five benign thyroid conditions and four thyroid cancers, including three papillary thyroid cancers and one bilateral medullary thyroid cancer in a patient with multiple endocrine neoplasia 2a. In two patients, it was a false-positive IONM loss. One of these two patients had the other lobe removed at day 3. In seven patients the laryngoscopy demonstrated total or partial laryngeal nerve palsy at day 1, but the recurrent nerve function recovered fully in all patients between 1 and 4 months postoperatively. All cancer patients were operated on the other side within 3 days to 3 months; one patient with a benign condition is being followed conservatively. One of the eight re-operated patients had transient recurrent nerve palsy postoperatively.

CONCLUSION

In our opinion, the systematic use of IONM and the change in operative strategy will lead to an almost 0% rate of bilateral laryngeal nerve palsy, at least in benign thyroid conditions. A loss of signal after the first side should prompt a halt in the procedure, even in cases of malignancies.

Robot-assisted thoracoscopic lymphadenectomy along the left recurrent laryngeal nerve for esophageal squamous cell carcinoma in the prone position: technical report and short-term outcomes

BACKGROUND

Meticulous mediastinal lymphadenectomy frequently induces recurrent laryngeal nerve palsy (RLNP). Surgical robots with impressive dexterity and precise dissection skills have been developed to help surgeons perform operations. The objective of this study was to determine the impact on short-term outcomes of robot-assisted thoracoscopic radical esophagectomy performed on patients in the prone position for the treatment of esophageal squamous cell carcinoma, including its impact on RLNP.

METHODS

A single-institution nonrandomized prospective study was performed. The patients (n = 36) with resectable esophageal squamous cell carcinoma were divided into two groups: patients who agreed to robot-assisted thoracoscopic esophagectomy with total mediastinal lymphadenectomy performed in the prone position (n = 16, robot-assisted group) without insurance reimbursement, and those who agreed to undergo the same operation without robot assistance but with health insurance coverage (n = 20, control group). These patients were observed for 30 days following surgery to assess short-term surgical outcomes, including the incidence of vocal cord palsy, hoarseness, and aspiration.

RESULTS

Robot assistance significantly reduced the incidence of vocal cord palsy (p = 0.018) and hoarseness (p = 0.015) and the time on the ventilator (p = 0.025). There was no in-hospital mortality in either group. There were no significant differences between the two groups with respect to patient background, except for the use of preoperative therapy (robot-assisted group <control, p = 0.003). There were no significant differences in estimated blood loss, operating time, number of dissected lymph nodes, completeness of resection, or the incidence of the other complications, except for anastomotic leakage (p = 0.038).

CONCLUSION

Robot-assisted thoracoscopic esophagectomy with total mediastinal lymphadenectomy is feasible and safe. This method shows promise in preventing RLNP.

Reoperations for primary hyperparathyroidism--improvement of outcome over two decades

PURPOSE

Reoperations (R-PTX) for primary hyperparathyroidism (pHPT) are challenging, since they are associated with increased failure and morbidity rates. The aim was to evaluate the results of reoperations over two decades, the latter considering the implementation of Tc(99m)sestamibi-SPECT (Mibi/SPECT), intraoperative parathormone (IOPTH) measurement, and intraoperative neuromonitoring (IONM).

PATIENTS AND METHODS

Data of 1,363 patients who underwent surgery for pHPT were retrospectively analyzed regarding reoperations. Causes of persistent (p) pHPT or recurrent (r) pHPT, preoperative imaging studies, surgical findings, and outcome were analyzed. Data of patients who underwent surgery between 1987 and 1997 (group 1; G1) and between 1998 and 2008 (group 2; G2) with the use of Mibi/SPECT, IOPTH, and IONM were evaluated.

RESULTS

One hundred twenty-five patients with benign ppHPT (n = 108) or rpHPT (n = 17) underwent reoperations (R-PTX). Group 1 included 54, group 2 71 patients. Main cause of ppHPT (G1 = 65 % vs. G2 = 53 %) and rpHPT (G1 = 80 % vs. G2 = 60 %) was the failed detection of a solitary adenoma (p = 0.2). Group 1 patients had significantly less unilateral/focused neck re-explorations (G1 = 23 % vs. G2 = 57 %, p = 0.0001), and more sternotomies (G1 = 35 vs. G2 = 14 %, p = 0.01). After a median follow-up of 4 (range 0.9-23.4) years, reversal of hypercalcemia was achieved in 91 % (G1) and in 98.6 % in group 2 (p = 0.08, OR 7.14 [0.809-63.1]). The rates of permanent recurrent laryngeal nerve palsy (G1 = G2 = 9 %, p = 1) and of postoperative permanent hypoparathyroidism (G1 = 9 % vs. G2 = 6 %, p = 0.5) were not significantly different. Other complications such as wound infection, postoperative bleeding, and pneumonia were significantly lower in group 2 (p < 0.001).

CONCLUSION

Nowadays, cure rates of R-PTX are nearly the same as in primary operations for pHPT. These results can be achieved in high-volume centers by routine use of well-established preoperative Mibi/SPECT and US in combination with IOPTH. However, morbidity is still considerably high.

Effect of intraoperative neuromonitoring on recurrent laryngeal nerve palsy rates after thyroid surgery--a meta-analysis

BACKGROUND/PURPOSE

Though intraoperative nerve monitoring (IONM) during thyroid surgery has gained universal acceptance for localizing and identifying the recurrent laryngeal nerve (RLN), its role in reducing the rate of RLN injury remains controversial. In order to assess the effect of IONM during thyroid surgery, its value in reducing the incidence of RLN palsy was systematically evaluated.

METHODS

Studies were evaluated for inclusion in this analysis by researching PubMed, Embase, the Cochrane Central Register of Controlled Trials, and the references of included studies. The initial screening of article titles and abstracts was independently performed by five reviewers based on the research protocol criteria. Each article was then read in detail and discussed before inclusion in the meta-analysis. Data were independently extracted, including the level of evidence, number of at-risk nerves, allocation method, baseline equivalence between groups, definitions of transient and permanent vocal fold palsy, systematic application of electrodes, etc. The meta-analysis was then performed. Odds ratios were pooled using a random effects model.

RESULTS

Five randomized clinical trials and 12 comparative trials evaluating 36,487 at-risk nerves were included. Statistically significant differences in terms of total recurrent laryngeal nerve palsy (3.37% with intraoperative nerve monitoring [IONM] vs. 3.76% without IONM [OR: 0.74; 95% confidence interval [CI]: 0.59-0.92]) and transient recurrent laryngeal nerve palsy (2.56% with IONM vs. 2.71% without IONM [OR: 0.80; 95% CI: 0.65-0.99]) were identified. The persistent incidence of recurrent laryngeal nerve palsy was 0.78% for IONM versus 0.96% for nerve identification alone (OR: 0.80; 95% CI: 0.62-1.03).

CONCLUSION

Based on this meta-analysis, statistically significant differences were determined in terms of the incidences of total and transient recurrent laryngeal nerve palsy after using IONM versus recurrent laryngeal nerve identification alone during thyroidectomy. However, no statistically significant differences were identified regarding the incidence of persistent recurrent laryngeal nerve palsy between groups.

Recurrent laryngeal nerve monitoring during esophagectomy and mediastinal lymph node dissection

BACKGROUND

Patients who undergo surgery to the esophagus and lungs are in jeopardy of recurrent laryngeal nerve (RLN) damage during the procedure. This study was designed to investigate the feasibility of intraoperative monitoring of the RLN for single-lung ventilation esophagus and lung surgery.

METHODS

Twelve consecutive patients booked for esophagus or lung surgery were included in this prospective, observational study. Six patients underwent transthoracic esophagectomy for carcinoma of the esophagogastric junction or lower esophagus, five had a lobectomy, and one underwent a pneumonectomy for lung carcinoma. Intraoperative, noninvasive RLN identification and monitoring was performed unilaterally (n = 8) or bilaterally (n = 4) using a handheld stimulator and a laryngeal surface electrode. The correct functioning of the nerve monitoring system was tested directly at the vagus nerve. Diagnosis of postoperative RLN paralysis was performed using indirect laryngoscopy.

RESULTS

During the surgical procedures, we monitored a nerve signal in all 12 patients. In one patient with lower esophagus carcinoma, a nerve signal could be detected only on one side. Postoperative indirect laryngoscopy showed normal vocal cord movement in all patients.

CONCLUSIONS

Intraoperative RLN identification and monitoring during single-lung ventilation surgery is technically feasible, easy, and reliable. The introduction of standardized RLN monitoring during this type of surgery may reduce the incidence of permanent RLN paralysis.

Influence of nondepolarizing muscle relaxants on intraoperative neuromonitoring during thyroid surgery

OBJECTIVE

The objective of this study was to find a nondepolarizing muscle relaxant to replace succinylcholine during thyroid surgery with intraoperative neuromonitoring (IONM) because succinylcholine can cause severe adverse effects.

DESIGN

Prospective study of 232 patients undergoing thyroidectomies.

SETTING

A tertiary medical centre.

METHODS

One hundred thirty-one patients received 0.5 mg/kg rocuronium (group R) and 101 patients received 0.5 mg/kg atracurium (group A) to facilitate electromyographic (EMG) endotracheal tube insertion. EMG signals were obtained from the vagus nerve before and after dissection of the recurrent laryngeal nerve and were defined as the V1 and the V2 signal, respectively. Accelerometry (twitch [% TW]) was used to monitor the quantitative degree of neuromuscular transmission at the adductor pollicis muscle.

MAIN OUTCOME MEASURES

The amplitude (muV) of the V1 and V2 signals and the correlated degree of neuromuscular transmission (% TW).

RESULTS

V1 and V2 signals were obtained from all patients successfully. The % TW at the V1 signal was significantly lower than that at the V2 signal in group R and group A. The mean recovery time from complete neuromuscular blockade to the initial twitch was 43.9 +/- 11 minutes. Only in the subgroup in which the correlated TW was 0% while eliciting the V1 signal were the amplitudes of the V1 signals significantly lower than those of the V2 signal in both groups.

CONCLUSIONS

A single dose (0.5 mg/kg) of rocuronium and atracurium was feasible for IONM during thyroid surgery. This study showed that 44 minutes after administration of these two muscle relaxants is adequate for eliciting an EMG signal from the vagus nerve.

Non-recurrent laryngeal nerve related to thyroid surgery: a report of 5 cases and literature review

BACKGROUND

Non-recurrent laryngeal nerve, a rare anomaly, passes transversely into larynx with or without its recurrent branches directly arising from the vagus nerve. The paper investigates clinical significance of non-recurrent laryngeal nerve during thyroid surgery. Clinical data from 5 cases of non-recurrent laryngeal nerve and related literature reviews were made to acknowledge its incidence, variant types and matters concerned during thyroid operations.

CASE REPORT

821 recurrent laryngeal nerves were anatomized during 2496 thyroid operations, from which 5 were confirmed to hold non-recurrent laryngeal nerves (0.61%). 3 patients were found to have non-recurrent laryngeal nerves during re-operation because of voice horse after the first operation which improved much after re-operation. The other two patients were recognized during the first operation. All 5 cases were not diagnosed preoperatively.

CONCLUSIONS

Non-recurrent laryngeal nerve, a rare anomaly, is very vulnerable during thyroid surgery. It is helpful to avoid injuring non-recurrent laryngeal nerve that identification of the non-recurrent laryngeal nerve and its types.

Intraoperative recurrent laryngeal nerve monitoring during surgery for left lung cancer

OBJECTIVE

This study evaluated the safety and efficacy of intraoperative recurrent laryngeal nerve monitoring during surgery for left lung cancer.

METHODS

From April 2008 to April 2009, a total of 25 patients at high risk for left recurrent laryngeal nerve injury agreed to and underwent intraoperative recurrent laryngeal nerve monitoring during surgery for left lung cancer in our hospital. Results and clinical records were reviewed.

RESULTS

All the patients' left recurrent laryngeal nerves were identified during operation by intraoperative recurrent laryngeal nerve monitoring. Twenty-four patients retained normal left recurrent laryngeal nerves after the operation. One patient, in whom part of the left recurrent laryngeal nerve was found to be invaded, underwent single-stage nerve anastomosis under recurrent laryngeal nerve monitoring after the invaded nerve was resected. There were no significant intraoperative or postoperative complications among the other patients.

CONCLUSIONS

Intraoperative recurrent laryngeal nerve monitoring during thoracotomy is a safe and effective way of identifying the nerve. It may help surgeons to avoid injuring the recurrent laryngeal nerve during some thoracic procedures.

[Intraoperative identification of the recurrent laryngeal nerves in thyroid surgery]

Accidental injury to the recurrent laryngeal nerve is a common complication of thyroid surgery. Different mechanisms of injury have been described, such as mechanical, electrical, or thermal. Retrosternal operations, secondary bleeding requiring wound revision, or neoplastic tumors are also frequent causes of this complication. Intraoperative direct stimulation of suspected nerve structures as well as vagal nerve stimulation have been proposed to avoid the injury. The effect of stimulation can be assessed by direct observation of the vocal cords (direct laryngoscopy or fiberoscopy via a laryngeal mask airway), or electromyography of the posterior cricoarytenoid muscle. All of these methods limit the use of muscle relaxants during anaesthesia. Details of anaesthetic management are presented.