Neuromonitoring in thyroid surgery

Intraoperative intermittent neuromonitoring of inferior laryngeal nerve and staged thyroidectomy: our experience

PURPOSE

To evaluate the reliability of intermittent intraoperative neuromonitoring (I-IONM) through recurrent laryngeal nerve (RLN) stimulation and laryngeal palpation in predicting postoperative vocal cord palsy and to examine the reliability of this technique in providing useful information in the decision to perform a staged surgery in initially planned total thyroidectomy.

METHODS

This was a retrospective cohort study of patients who underwent thyroid surgery at the ENT Department of the University of Bologna from January 2014 to June 2017. In all cases, preoperative and postoperative laryngoscopy was performed. All surgeries were conducted with I-IONM and RLN simultaneous laryngeal palpation (NSLP) to detect contraction (laryngeal twitch) of the posterior crico-arytenoid muscle. The incidence of vocal cord palsy was calculated for nerves at risk. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated with a confidence interval determined at 95% level.

RESULTS

Seven hundred and sixteen patients were enrolled in the study. The incidence of vocal cord palsy was 3.16%. Specificity of I-IONM in predicting vocal cord paralysis was 99.1% and sensitivity was 90%. The NPV was 99.7% and PPV 78.3%. Two-stage thyroidectomy (ST) was performed in 22 cases (22/570: 3.85%). Six patients (27.3%) were false positive and 16 true positive (72.7%) at I-IONM.

CONCLUSION

High sensitivity and specificity values confirm the validity of I-IONM with NSLP in predicting postoperative normal vocal cord function. Our results confirm that I-IONM may safely guide an ST overall in benign thyroid diseases and in low-grade malignancies.

Surgical management of intrathoracic goitres

BACKGROUND

Intrathoracic goitres (ITG) often present with compressive symptoms and require specialised care by experienced surgical teams. Most ITG can be accessed by a transcervical approach (TCA) and only between 1 and 15% will require an extracervical approach (ECA). Many controversies exist regarding the clinical presentation, evaluation, selection of cases for ECA, surgical technique and outcomes. This paper reviews the recent literature on the management, outcomes and evidence-based treatment strategies of ITG.

METHODS

We conducted a review of the literature on the evaluation, management and outcomes of surgery for ITGs.

RESULTS

The incidence of cancer in the ITGs ranges between 4 and 20%. Multiplanar CT scanning offers the best preoperative evaluation and aids to determine the approach. Most ITG can be accessed by TCA and ECA are only needed in maximum 15% of cases. In experienced hands, the outcome of these surgeries is comparable to thyroid surgery for non-ITG.

CONCLUSIONS

Surgery for ITG is challenging. The experienced surgeon however, with few exceptions can address ITG via TCA, with outcomes comparable to those of uncomplicated thyroid surgery.

Experience with intraoperative neuromonitoring of the recurrent laryngeal nerve improves surgical skills and outcomes of non-monitored thyroidectomy

PURPOSE

Intraoperative neuromonitoring (IONM) can serve as a tool to increase skills in recurrent laryngeal nerve (RLN) identification and complete removal of thyroid tissue. The aim of this study was to validate this hypothesis.

METHODS

This prospective study involved 632 patients (1161 RLNs at risk) who underwent thyroid surgery in 2011-2014. Although IONM was not used until 2012, this prospective study started on 1 January 2011. The three participating surgeons knew about the study before that date and that the rate of RLN identification would be carefully measured in total and near-total surgery. Solely, visual identification of the RLN was used throughout 2011. IONM was introduced as a training tool in 2012-2014 for the first 3 months of each year. In the remaining months, thyroid operations were performed without IONM. Outcomes of non-monitored thyroid operations were compared before (01-12/2011) vs. after (04-12/2012-2014) 3 months of exposure to IONM yearly (01-03/2012-2014). The rate of RLN identification was assessed in total and near-total thyroidectomies and in totally resected lobes in Dunhill's operation. The prevalence of RLN injury and the utilization of total thyroidectomy were evaluated.

RESULTS

In 2011, the rate of successful RLN visual identification in total and near-total thyroidectomies and in totally resected lobes in Dunhill's operation was 45.71 %. After the introduction of IONM in 2012-2014, in the procedures performed without IONM, the rate was 86.66, 90.81, and 91.3 %. The prevalence of RLN injury in 2011 was 6.8 %, while in the years following the introduction of IONM, it was 3.61, 2.65, and 1.45 %. Utilization of total thyroidectomy increased from 47.9 % in 2011 to 100 % in 2014.

CONCLUSIONS

Experience with IONM led to an increase in RLN identification (p < 0.0001), a decrease of RLN injury (p < 0.05), and an increase in the safe utilization of total thyroidectomy (p < 0.0001) in non-monitored thyroid operations. IONM is a valuable tool for surgical training.

Staged Surgery for Advanced Thyroid Cancers: Safety and Oncologic Outcomes of Neural Monitored Surgery

Objective

Thyroidectomy with extensive multicompartment bilateral neck dissections for advanced-stage thyroid cancer may lead to increased risk of complications, including bilateral recurrent laryngeal nerve (RLN) paralysis and hypoparathyroidism. A planned staged approach derived from a detailed preoperative radiographic map is associated with a low complication profile. This study evaluates oncologic results and safety of neural monitored, staged thyroid cancer surgery for management of advanced thyroid cancer.

Study Design

Case series with chart review.

Setting

Tertiary care center.

Subjects and Methods

With institutional review board approval, 35 consecutive patients with advanced thyroid malignancy and extensive nodal disease managed with staged surgery between January 2004 and May 2013 by the senior author (G.W.R.) were identified, and the oncologic and surgical outcomes were reviewed.

Results

In total, 37.2% of patients had stage III or IV disease, with extrathyroidal extension in 71.4%, vascular invasion in 51.4%, and RLN invasion in 17% of patients. A total of 34% patients had positive lymph nodes in more than 5 nodal compartments; the average positive lymph node yield was 17, and extranodal extension was present in 51%. Three patients had RLN sacrifice, and there were no other cases of temporary or permanent RLN paralysis; permanent hypoparathyroidism and chyle leak occurred in one patient each. Locoregional recurrence occurred in 5.7% of patients after a 147-week mean follow-up. In patients with papillary thyroid carcinoma, median postoperative nonstimulated and stimulated thyroglobulin levels were 0.2 and 0.75 ng/mL, respectively.

Conclusion

A neural monitored, staged surgical approach was conducted without significant adverse events in this small sample and represents and effective alternative strategy option to simultaneous bilateral surgery in the management of thyroid cancer with extensive neck metastases.

The learning curve for intraoperative neuromonitoring of the recurrent laryngeal nerve in thyroid surgery

Purpose

Intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) is often used in thyroid surgery. However, this procedure is complex and requires a learning period to master the technique. The aim of the study was to evaluate the learning curve for IONM.

Methods

A 3-year period (2012–2014) of working with IONM (NIM3.0, Medtronic) was prospectively analyzed with a special emphasis on comparing the initial implementation phase in 2012 (101 patients, 190 RLNs at risk) with subsequent years of IONM use in 2013 (70 patients, 124 RLNs at risk) and 2014 (65 patients, 120 RLNs at risk).

Results

The rate of successful IONM-assisted RLN identification increased gradually over the 3-year study period (92.11 % in 2012 vs. 95.16 % in 2013 vs. 99.16 % in 2014; p = 0.022), with a corresponding decrease in the rate of technical problems (12.87, 4.3, and 4.6 %, respectively; p = 0.039). The rate of RLN injuries tended to decrease over time: 3.68, 1.55, and 0.83 %, respectively (p = 0.220). Between 2012 and 2014, increases in the sensitivity (71.4 vs. 100 %), specificity (98 vs. 99 %), positive predictive value (62.5 vs. 75 %), negative predictive value (98 vs. 100 %), and overall accuracy of IONM (97.4 vs. 99.6 %) were observed (p = 0.049). Increasing experience with IONM resulted in more frequent utilization of total thyroidectomy (92 % in 2012 vs. 100 % in 2013–2014; p = 0.004).

Conclusions

There was a sharp decrease in the number of technical problems involving equipment setup from 2012 to 2014.

Prospective study of vocal fold function after loss of the neuromonitoring signal in thyroid surgery: The International Neural Monitoring Study Group's POLT study

OBJECTIVES/HYPOTHESIS

Intraoperative neuromonitoring identifies recurrent laryngeal nerve (RLN) injury and gives prognostic information regarding postoperative glottic function. Loss of the neuromonitoring signal (LOS) signifies segmental type 1 or global type 2 RLN injury. This study aimed at identifying risk factors for RLN injury and determining vocal fold (VF) function initially and 6 months after definitive LOS.

STUDY DESIGN

Prospective study encompassing 21 hospitals from 13 countries.

METHODS

Included in this study were patients with persistent intraoperative LOS.

RESULTS

At first postoperative laryngoscopy, early VF palsy was present in 94 of all 115 patients with LOS (81.7%): in 53 of 56 patients (94.6%) with type 1 injury and 41 of 59 patients (69.5%) with type 2 injury. In LOS type 1, women outnumbered men >5-fold. Traction produced LOS type 1 in 38 of 56 patients (67.9%) and LOS type 2 in 54 of 59 patients (91.5%). Course of the RLN posterior and/or anterior to the inferior thyroid artery, extralaryngeal branching, or tuberculum of Zuckerkandl did not increase VF palsy rates. Permanent VF palsy rates were also lower (P = .661) after LOS type 2 than after LOS type 1: 6.8% (four of 59 patients) versus 10.7% (six of 56 patients). Intraoperative administration of steroids did not diminish postoperative VF palsy rates.

CONCLUSIONS

LOS type 1 entails more severe nerve damage than LOS type 2, affecting women disproportionately. Both LOS types, being primarily associated with traction injury, are unaffected by variant neck anatomy in expert hands and unresponsive to steroids.

LEVEL OF EVIDENCE

2b Laryngoscope, 126:1260-1266, 2016.

Anaesthesia for goitre surgery: A review

Goitres are relatively common and, in extreme cases, present unique challenges (particularly in airway management) for the anaesthetist. There are no specific guidelines from the Difficult Airway Society (United Kingdom) or the American Society of Anesthesiologists for the management of the obstructed airway. We therefore present the principles governing the provision of safe anaesthesia for goitre surgery including formulating a plan ABC for patients with a stable airway and for those presenting with acute airway obstruction.

Loss of neuromonitoring signal during bilateral thyroidectomy: no systematic change in operative strategy according to a survey of the French Association of Endocrine Surgeons (AFCE)

Background

Total thyroidectomy presents a risk of bilateral vocal cord paralysis, which can lead to compromised airway. Visual Recurrent Laryngeal Nerve (RLN) identification significantly decreases this risk of RLN lesion. Yet, an anatomically intact nerve is not always functional. Intraoperative neuromonitoring (IONM) allows to test in real time the function of the RLN. In case of loss of signal (LOS) on the first operated side, some authors recommend to stop the intervention. The purpose of this study was to characterize the operative strategy of the French-speaking surgeons in case of LOS on the first side in planned bilateral thyroidectomies.

Methods

An online questionnaire was sent to the surgeons of the French Association of Endocrine Surgeons (AFCE).

Results

We collected 69 responses (response rate: 42 %). Forty-six surgeons (66 %) used IONM. After a signal loss, 22 % (N = 10) stopped the operation in all cases, 24 % (N = 11) continued the operation in case of malignant disease and stopped in cases of benign disease, and 54 % (N = 25) continued the operation contralaterally.

Conclusions

The majority of surgeons continued the operation contralaterally as originally planned despite a loss of IONM signal at the end of the first side.

Identification alone versus intraoperative neuromonitoring of the recurrent laryngeal nerve during thyroid surgery: experience of 2034 consecutive patients

BACKGROUND

The aim of this study was to evaluate the ability of intraoperative neuromonitoring in reducing the postoperative recurrent laryngeal nerve palsy rate by a comparison between patients submitted to thyroidectomy with intraoperative neuromonitoring and with routine identification alone.

METHODS

Between June 2007 and December 2012, 2034 consecutive patients underwent thyroidectomy by a single surgical team. We compared patients who have had neuromonitoring and patients who have undergone surgery with nerve visualization alone. Patients in which neuromonitoring was not utilized (Group A) were 993, patients in which was utilized (group B) were 1041.

RESULTS

In group A 28 recurrent laryngeal nerve injuries were observed (2.82%), 21 (2.11%) transient and 7 (0.7%) permanent. In group B 23 recurrent laryngeal nerve injuries were observed (2.21%), in 17 cases (1.63%) transient and in 6 (0.58%) permanent. Differences were not statistically significative.

CONCLUSIONS

Visual nerve identification remains the gold standard of recurrent laryngeal nerve management in thyroid surgery. Neuromonitoring helps to identify the nerve, in particular in difficult cases, but it did not decrease nerve injuries compared with visualization alone. Future studies are warranted to evaluate the benefit of intraoperative neuromonitoring in thyroidectomy, especially in conditions in which the recurrent nerve is at high risk of injury.

The neoplastic goitre

PURPOSE OF REVIEW

To highlight recent advances in our understanding of the incidence of multinodular goitre (MNG) risk of malignancy, evaluation of patients with MNG, rates and factors predictive of malignancy in MNG, and the choice of surgical procedure for patients with neoplastic MNG.

RECENT FINDINGS

The incidence of MNG when screened by ultrasound scanning (USS) is between 10 and 20% and when using high resolution USS can be up to 70%. The incidence of occult malignancy within MNG lies between 10 and 35% in surgical series. Younger patients and men have higher rates of malignancy, as do patients with a family history, prior irradiation and those with signs of compressive or invasive disease. Subtotal thyroidectomy has been rejected in favour of either total lobectomy or total thyroidectomy for most patients with MNG.

SUMMARY

An increasing number of patients with MNG will be encountered in surgical practice. Most patients can be cured with total lobectomy or total thyroidectomy, which minimizes recurrence rates and ensures an oncological approach to patients with incidentally discovered malignancy within MNG.

Which hemostatic device in thyroid surgery? A network meta-analysis of surgical technologies

BACKGROUND

Energy-based hemostatic devices are increasingly being used in thyroid surgery. However, there are several limitations with regard to the existing evidence and a paucity of guidelines on the subject. The goal of this review is to employ the novel evidence synthesis technique of a network meta-analysis to assess the comparative effectiveness of surgical technologies in thyroid surgery and contribute to enhanced governance in the field of thyroid surgery.

METHODS

Articles published between January 2000 and June 2012 were identified from Embase, Medline, Cochrane Library, and PubMed databases. Randomized controlled trials of any size comparing the use of ultrasonic coagulation (harmonic scalpel) or Ligasure either head-to-head or against the "clamp-and-tie" technique were included. Two reviewers independently critically appraised and extracted the data from each study. The number of patients who experienced postoperative events was extracted in dichotomous format or continuous outcomes. Odds ratios were calculated by a Bayesian network meta-analysis, and metaregression was used for pair-wise comparisons. Indirect and direct comparisons were performed and inconsistency was assessed.

RESULTS

Thirty-five randomized controlled trials with 2856 patients were included. Ultrasonic coagulation ranked first (followed by Ligasure and then clamp-and-tie) with the lowest risk of postoperative hypoparathyroidism (odds ratio 1.43 [95% confidence interval (CI) 0.77-2.67] and 0.70 [CI 0.43-1.13], ultrasonic coagulation vs. Ligasure and ultrasonic coagulation vs. clamp-and-tie, respectively), least blood loss (-0.25 [CI -0.84 to -0.35] and -1.22 [CI -1.85 to -0.59]), and drain output (0.28 [CI -0.35 to -0.91] and -0.36 [CI -0.70 to -0.03]). From a health technology viewpoint, ultrasonic coagulation was associated with the shortest operative time (-0.66 [CI -1.17 to -0.14] and -1.29 [CI -1.59 to -1.00]) and hospital stay (-0.28 [CI -0.78 to 0.22] and -0.56 [CI -1.28 to 0.15]). The only exception occurs with the clinically important complication of recurrent laryngeal nerve paralysis, where the reverse trend applies (1.36 [CI 0.25-7.46] and 1.74 [CI 0.94-3.26]).

CONCLUSIONS

The comparative effectiveness of ultrasonic coagulation in thyroid surgery outcomes seems superior to other techniques with the exception of recurrent laryngeal nerve injury. This network meta-analysis, one of a handful in a surgical field, offers preliminary and robust evidence to guide clinical decisions and policy makers to adopt safer thyroid operations.

Neuromonitoring of the laryngeal nerves in thyroid surgery: a critical appraisal of the literature

One of the most significant complication of thyroid surgery is injury of the recurrent laryngeal nerve. Injury of the external branch of the superior laryngeal nerve is a less obvious but occasionally significant problem. Recently, neuromonitoring during thyroidectomy has received considerable attention because of literature encouraging its use, but there is no consensus about its advantages and utility. A critical assessment of the literature on neuromonitoring was conducted in order to define its effectiveness, safety, cost-effectiveness and medical-legal impact. Available data does not show results superior to those obtained by traditional anatomical methods of nerve identification during thyroid surgery. Data about cost-effectiveness is scarce. The literature shows inconsistencies in methodology, patient selection and randomization in various published studies which may confound the conclusions of individual investigations. The current recommendation for use in "high risk" patients should be assessed because definition heterogeneity makes identification of these patients difficult. As routine use of neuromonitoring varies according to geography, its use should not be considered to be the standard of care.