The cost of vocal fold paralysis after thyroidectomy

Duration of Effect and Associated Factors of Injection Laryngoplasty

OBJECTIVE

Injection laryngoplasty (IL) has become a mainstay in the treatment of unilateral vocal fold paralysis due to technical ease and avoidance of open surgery. The duration of IL effect depends on the injected material and has not been defined clearly. We aimed to define the effective duration of IL and to investigate the associated factors.

METHODS

Fifty-nine patients who underwent IL for unilateral vocal fold paralysis were included. IL was performed using a cricothyroid membrane approach under local anesthesia. During follow-up, in cases that developed subjective hoarseness with objective glottic insufficiency, a second IL was performed, and loss of IL effect was recorded. The duration of IL was analyzed using Kaplan-Meier estimates, and the associations between duration of effect and various factors such as postinjection voice therapy, injected material, and cause of paralysis were investigated using log-rank test.

RESULTS

Of 59 patients, 20 (33.9 %) received a second IL. The median time interval between the first and second IL was 3.3 months (95% CI, 0.4∼27.8 months). The mean duration of effect after IL was 42.5 months (95% CI, 32.1∼52.9 months), and the rate of persisting effect was 63.4% at 1-year after IL (1-year effect rate) and 59.4% at 2 years after IL. The 1-year effect rate was 80.8% in cases with postinjection voice therapy and 57.8% in those without postinjection voice therapy (P = 0.084). Injected material, DM, HTN, patient age and sex, and cause of paralysis had no effect on the 1-year effect rate.

CONCLUSIONS

The mean duration of IL effect was 42.5 months, and the rate of persisting effect was 63.4% at 1-year after IL. There were no significant factors affecting the duration of effect, although the duration tended to be slightly longer in cases with postinjection voice therapy. Further study with a prospective, randomized design is needed.

The impact of intraoperative neural monitoring during papillary thyroid cancer surgery on completeness of thyroidectomy and thyroglobulin response: a propensity-score matched study

BACKGROUND

Intraoperative neural monitoring (IONM) has been utilized for a variety of thyroid pathologies, including papillary thyroid carcinoma (PTC). Remnant thyroid tissue following total thyroidectomy (TT) in patients with PTC is associated with increased recurrence. The aim of this study is to investigate whether the use of IONM in PTC surgery has an impact on the completeness of thyroidectomy.

METHODS

Retrospectively, patients with preoperative diagnosis of PTC, who underwent TT in a tertiary center were reviewed. They were grouped based on the IONM usage, and 1:1 propensity-score match was performed. Primary outcome was the completeness of thyroidectomy, determined by measuring postoperative stimulated thyroglobulin levels (sTg).

RESULTS

Among 274 clinically node-negative PTC patients who underwent TT and ipsilateral prophylactic central lymph-node dissection, a total of 170 patients (85:85) were matched. Postoperative sTg levels were significantly lower in the IONM group (1 ng/dL vs. 0.4 ng/dL; p < 0.01) with higher percentage of the patients with sTg levels <1 ng/ml (50.6% vs. 69.4%; p = 0.01). More patients in the no-IONM group received RAI ablation with significantly higher doses (mean mci: 120 vs. 102; p = 0.02).

CONCLUSION

The use of IONM during thyroidectomy provides improvement in the completeness of thyroidectomy and reduction in postoperative sTg levels which can be used as a guide by clinicians to avoid RAI ablation in selected PTC patients and to adjust low ablative doses in patients who are scheduled for remnant ablation.

Continuous Intraoperative Nerve Monitoring of a Non-Recurrent Laryngeal Nerve: Real-Life Data of a High-Volume Thyroid Surgery Center

Thyroid surgery is associated with a risk of injury to the recurrent laryngeal nerve, especially in the presence of anatomical variants such as a non-recurrent laryngeal nerve (NRLN). Injury to the nerve leads to transient or permanent vocal cord palsy (VCP). A novel method to prevent VCP is continuous intraoperative nerve monitoring (cIONM), but less is known about the applicability of this method in patients with NRLN. The aim of this study was to evaluate our own data regarding feasibility and detailed characteristics of cIONM in NRLN patients. We performed a monocentric retrospective cohort analysis including clinical data and intraoperative nerve monitoring data (measured by Inomed Medizintechnik GmbH, Emmendingen, 'C2' and 'C2 Xplore' device) of all thyroid surgery patients, showing NRLN between 2014 and 2022. Of 1406 patients who underwent thyroid surgery with cIONM between 2014 and 2022, 12 patients (0.9%) showed NRLN intraoperatively. Notably, cIONM was feasible in eight patients (67%). In all cases the onset latency of the right vagus nerve was shorter (<3.0 ms) than usually expected, suggesting that a short latency might be suitable to distinguish NRLN. None of the patients had a post-operative VCP. Overall, cIONM appears to be feasible and safe in NRLN patients and provides helpful information to prevent VCP.

Association of Sociodemographic Factors on the Presentation and Management of Unilateral Vocal Fold Immobility

OBJECTIVE

To determine the association of social determinants of health (SDOH) on the presentation and management of unilateral vocal fold immobility (UVFI).

METHODS

Retrospective chart review of 207 adult UVFI patients evaluated at a tertiary-care hospital between 2018 and 2019 was performed. Sociodemographic factors including gender, median household income, preferred language, and insurance type were recorded. Confounding clinical factors including etiology of UVFI, Voice Handicap Index-10 (VHI-10) score, laryngoscopic findings, and intervention history were extracted from medical records. Multivariable logistic regression was performed using sociodemographic and clinical factors.

RESULTS

Patient demographics and socioeconomic status were not associated with time to presentation. Patients presenting with glottic insufficiency and UVFI due to malignancy or recurrent laryngeal nerve (RLN) sacrifice had a shorter time to presentation. Higher household income was associated with greater number of interventions (p = 0.02), but neither income nor insurance type affected intervention type or timing. Female patients were less likely to undergo injection medialization laryngoplasty (odds ratio [OR] 0.25, p = 0.005). Older patients were more likely to undergo injection (OR 1.04, p = 0.027). Patients with large glottic gaps (OR 21.2, p = 0.014) and higher VHI-10 scores (OR 1.06, p = 0.047) were more likely to undergo surgery.

CONCLUSION

Higher household income was associated with greater number of interventions and longer duration of care at a private tertiary-care hospital. RLN sacrifice, known malignancy, and glottic insufficiency significantly reduced the time to presentation. Type of intervention received was a complex interplay of both demographic and clinical factors. Large prospective studies should examine the role of SDOH in the presentation and management of UVFI.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:297-304, 2024.

Continuous Intraoperative Recurrent Laryngeal Nerve Monitoring: Techniques, Applications, and Controversies

Purpose of Review

Purpose of the present review is to illustrate the current state of the art concerning continuous intraoperative recurrent laryngeal nerve monitoring (cIONM) for thyroid surgery.

Recent Findings

cIONM potentially leads to an improved postoperative vocal cord palsy rate, compared to the intermittent technique. There are currently two main approaches for cIONM: either conventional cIONM based on vagal nerve stimulation or experimental methods, which do not require the positioning of a vagal nerve electrode. One of these methods is the recently described technique “LAR-cIONM,” which utilizes the laryngeal adductor reflex.

Summary

cIONM represents an advancement of intermittent nerve monitoring, which allows for an immediate reaction to signal changes. Threshold values and guidelines to prevent recurrent laryngeal nerve palsy were validated for the direct stimulation of the vagal nerve and require verification for alterative cIONM methods, including LAR-cIONM.

Comparison of a Handheld Device vs Endotracheal Tube-Based Neuromonitoring for Recurrent Laryngeal Nerve Stimulation

OBJECTIVE

To measure the effect of thyroidectomy difficulty on intraoperative neuromonitoring false loss of signal (LOS) and to compare intraoperative endotracheal tube-based neuromonitoring (ETNM) and Checkpoint palpation-based direct stimulation (pDS) signals with postoperative laryngoscopy. We hypothesized that pDS has higher a positive predictive value for postdissection confirmation of recurrent laryngeal nerve function than ETNM and that this difference is accentuated with increasing thyroidectomy difficulty.

STUDY DESIGN

Prospective single-arm cross-sectional study comparing ETNM and pDS for patients undergoing hemi-, total, or completion thyroidectomy from July 2018 to March 2020.

SETTING

Single-surgeon series at a tertiary care hospital.

METHODS

Percentage concordance and positive and negative predictive values were measured. Each thyroidectomy was assigned a validated thyroidectomy difficulty score, and recorded recurrent laryngeal nerve signals were compared with postoperative vocal fold mobility.

RESULTS

Percentage concordance was 90.09%. Positive and negative predictive values were 0.19 (95% CI, 0.09-0.31) and 1.0 for ETNM and 0.59 (95% CI, 0.35-0.82) and 1.0 for pDS. The difference in positive predictive value was significant (0.40 [95% CI, 0.33-0.47], P < .001). False LOS rates for ETNM and pDS were 13.19% versus 3.30% (9.89% [95% CI, 1.80%-18.62%], P = .0155), 44.11% versus 0% (44.11% [95% CI, 25.80%-60.54%], P < .001), and 73.33% versus 13.33% (60% [95% CI, 24.76%-78.46%], P = .001) for the second through fourth thyroidectomy difficulty score quartiles, respectively. False LOS with ETNM was linearly correlated with increasing difficulty (R² = 0.97).

CONCLUSION

ETNM was subject to high rates of postdissection false LOS that increased with thyroidectomy difficulty score. pDS is a reliable alternative that has higher positive predictive value than ETNM, particularly in more challenging cases such as those with posteriorly fixed thyroid cancers and fibrotic glands.

EVIDENCE LEVEL

2.

Differentiated Thyroid Cancer: A Health Economic Review

Simple Summary

This review reflects on health economic considerations associated with the increasing diagnosis and treatment of differentiated thyroid cancer. Analysis of different relevant health economic topics, such as overdiagnosis, overtreatment, surgical costs, and costs of follow-up are being addressed. Several unanswered research questions such as optimising molecular markers for diagnosis, active surveillance of primary tumours, and improved risk stratification and survivorship care all influence future healthcare expenditures.

Abstract

The incidence of differentiated thyroid cancer (DTC) is rising, mainly because of an increased detection of asymptomatic thyroid nodularity revealed by the liberal use of thyroid ultrasound. This review aims to reflect on the health economic considerations associated with the increasing diagnosis and treatment of DTC. Overdiagnosis and the resulting overtreatment have led to more surgical procedures, increasing health care and patients’ costs, and a large pool of community-dwelling thyroid cancer follow-up patients. Additionally, the cost of thyroid surgery seems to increase year on year even when inflation is taken into account. The increased healthcare costs and spending have placed significant pressure to identify potential factors associated with these increased costs. Some truly ground-breaking work in health economics has been undertaken, but more cost-effectiveness studies and micro-cost analyses are required to evaluate expenses and guide future solutions.

Comparison of stimulating dissector and intermittent stimulating probe for the identification of recurrent laryngeal nerve in reoperative setting

PURPOSE

Recurrent laryngeal nerve (RLN) paralysis is one of the most devastating complications after thyroidectomy. Thyroid reoperation is a great challenge for surgeons due to anatomical distortion and fibrosis and associated with a higher risk of RLN injury. In this study, we aimed to compare stimulating dissector (SD) with intermittent stimulating probe (ISP) in thyroid reoperations. This study is the first one which compares the impact of different nerve stimulating devices in thyroid reoperations.

METHODS

Included in this randomized prospective study were patients who had a bilateral subtotal thyroidectomy and would undergo a completion thyroidectomy due to a diagnosis of thyroid papillary cancer between January 2015 and January 2017. Patients were divided into two groups as SD group and ISP group. Age, sex, nerve amplitudes, latencies, the first identification time of RLN and complications were compared in both groups.

RESULTS

A total of 32 patients, 16 in both groups, were included in the study. The demographics, nerve signal amplitudes and latencies were similar in both groups (p > 0.05). The mean RLN identification time in the SD group was 17.4 ± 4.3 min, which was significantly shorter than those in the ISP group (mean 21.3 ± 3.9) (p = 0.014).

CONCLUSION

The first identification of RLN in the thyroid reoperations was faster with the use of SD than with the use of the ISP. Since the electromyographic amplitudes of RLN and vagus nerve with using SD were similar to the bipolar ISP, SD can be used safely for thyroid reoperations.

Medicolegal lessons learned from thyroidectomy-related lawsuits: an analysis of judicial precedents in South Korea from 1998 to 2019

Background

Thyroid cancer is one of the most common cancers in South Korea, and thyroidectomy is still frequently performed. As new diagnostic methods have led to a significant increase in the early detection of thyroid cancer worldwide, medical disputes related to thyroid surgery are also likely to increase. The purpose of this study was to investigate the causes of medical disputes related to thyroidectomy and to identify ways to prevent unnecessary disputes and malpractice.

Methods

We analyzed 35 judicial decisions involving thyroidectomy in South Korea from January 1998 to July 2019.

Results

The most common cause of lawsuits was "performance error during surgery" (n=19), especially "recurrent laryngeal nerve (RLN) injury" (n=7), of which five cases were ruled medical malpractice. For lawsuits involving misdiagnosis (n=14), five regarding fine needle aspiration cytology (FNAC) and frozen section examination were ruled malpractice. The most common malpractice related to informed consent was "lack of explanation about surgery complications" (n=10).

Conclusions

Surgeons should follow guidelines to protect themselves from diagnostic error dispute; performing FNAC more often might also prevent lawsuits. When the courts judge the surgeon's negligence in cases of RLN injuries, whether bilateral or unilateral, it is necessary to consider fully the surgeon's efforts to prevent RLN injuries. Providing information and building trust through sufficient patient-doctor communication is crucial.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

Intraoperative Neuromonitoring in Thyroid Surgery: An Efficient Tool to Avoid Bilateral Vocal Cord Palsy

OBJECTIVES

This study aimed to analyze the effects of intraoperative neuromonitoring (IONM) on the prevalence of vocal cord palsy (VCP) in thyroid surgery.

METHODS

Data from 493 patients (839 nerves at risk [NAR]) who underwent thyroid surgery between July 2014 and May 2016 were retrospectively evaluated. The patients were divided into 2 groups: Group 1 (G1) consisted of patients who underwent surgery without IONM, whereas group 2 (G2) consisted of patients who underwent surgery with IONM. The surgical techniques were identical, and experienced surgeons performed the procedures in both groups. Intraoperative neuromonitoring was performed in compliance with the International Neural Monitoring Guidelines.

RESULTS

In total, 211 patients (170 female, 41 male) with 360 NAR were included in G1, and 282 patients (220 female, 62 male) with 479 NAR were included in G2. The number of VCP per NAR in G1 and G2 was 33 (9.2%) and 27 (5.6%), respectively (P = .005). The number of transient VCP per NAR in G1 and G2 was 27 (7.5%) and 23 (4.8%; P = .230), respectively. The number of permanent VCP per NAR in G1 and G2 was 6 (1.7%) and 4 (0.8%; P = .341), respectively. Bilateral VCP was detected in 4 (2.7%) patients in G1, whereas there was no patient with bilateral VCP in G2 (P = .033).

CONCLUSIONS

Intraoperative neuromonitoring may decrease the incidence of total VCP and prevent the development of bilateral VCP, which has unfavorable results for both patients and health-care professionals.

Safety and feasibility of a novel recurrent laryngeal nerve monitoring technique

OBJECTIVES/HYPOTHESIS

Continuous intraoperative nerve monitoring (CIONM) during thyroidectomy is promising technology that may reduce the incidence of recurrent laryngeal nerve (RLN) injuries. However, the current technique for CIONM, in which a stimulating probe is placed on the vagus nerve, has not been widely adopted because of concerns regarding its invasiveness and safety. A new method with the lead positioned on the RLN may overcome these objections and promote greater adoption of CIONM. This study was conducted to serve as the first step in determining the safety and feasibility of an RLN-based CIONM approach.

STUDY DESIGN

Case series with planned data collection.

METHODS

Fifty patients scheduled to undergo thyroidectomy were enrolled. In all cases, after identification of the RLN, a lead designed for CIONM was placed on the nerve. The lead was then left in place for a minimum of 2 minutes, and CIONM data were recorded. Laryngeal electromyographic (EMG) characteristics were assessed just before the lead was placed on the RLN and after it was removed. Pre- and postoperative fiberoptic laryngoscopy was performed to assess vocal cord function in all patients.

RESULTS

In 49 patients (98%), the probe was successfully positioned on the RLN, and CIONM data were generated. On average, 1.4 attempts per patient were required to properly place the lead. No accidental dislodgements of the lead occurred during the experiments. No patients demonstrated significant EMG changes from baseline after manipulation and stimulation of the RLN. The average CIONM time was 175.7 s (range, 138-212 s), and the average CIONM amplitude and latency were 675.2 µV (range, 211.0-1405.2 µV) and 1.8 ms (1.25-1.9), respectively. All patients had normal bilateral vocal cord function preoperatively and at the first postoperative visit.

CONCLUSIONS

This study demonstrates the apparent safety and viability of a CIONM technique using a lead placed directly on the RLN. Future investigations are warranted of this promising method, which may promote more widespread adoption of CIONM during thyroidectomy to reduce RLN injuries.

LEVEL OF EVIDENCE

4 Laryngoscope, 2018.

Vocal palsy increases the risk of lower respiratory tract infection in low-risk, low-morbidity patients undergoing thyroidectomy for benign disease: A big data analysis

OBJECTIVES

Thyroidectomy is the commonest operation that places normally functioning laryngeal nerves at risk of injury. Vocal palsy is a major risk factor for dysphonia, dysphagia, and less commonly, airway obstruction. We investigated the association between post-thyroidectomy vocal palsy and long-term risks of pneumonia and laryngeal failure.

DESIGN

An N=near-all analysis of the English administrative dataset using a previously validated informatics algorithm to identify young and otherwise low-risk patients undergoing first-time elective thyroidectomy for benign disease. Information about age, sex, morbidities, social deprivation and post-operative and late complications were derived.

MAIN OUTCOME MEASURES

Between 2004 and 2012, 43 515 patients between the ages of 20 and 69 who had no history of cancer, neurological, or respiratory disease underwent elective total or hemithyroidectomy without concomitant or late neck dissection, parathyroidectomy or laryngotracheal surgery for benign thyroid disease for the first and only time. Information about age, sex, morbidities and in-hospital and late complications was recorded.

RESULTS

Mean age at surgery was 46±12. There was a strong female preponderance (85%), and most patients (89%) had no recorded Charlson comorbidities Most patients (65%) underwent hemithyroidectomy. Late vocal palsy was recorded in 449 (1.03%) patients, and its occurrence was an independent risk factor for emergency hospital readmission (n=7113; Hazard Ratio 1.52; 95% confidence interval 1.21-1.91), hospitalisation for lower respiratory tract infection (n=944; HR 2.04; 95% CI 1.07-3.75), dysphagia (n=564; HR 3.47; 95% CI 1.57-7.65) and gastrostomy/tracheostomy placement (n=80; HR 20.8; 95% CI 2.5-171.2). Independent risk factors for late vocal palsy were age, burden of morbidities, total thyroidectomy, post operative bleeding, male sex, and annual surgeon volume <30.

CONCLUSIONS

There is a significant association between post-thyroidectomy vocal palsy and long-term risks of hospital readmission, dysphagia, hospitalisation for lower respiratory tract infection, and gastrostomy/tracheostomy tube placement. This adds weight to the need, from a thyroid surgical perspective, to undertake universal post-thyroidectomy laryngeal surveillance as a minimum standard of care, with a focus on post-operative dysphagia and aspiration, and from a medical/respiratory perspective, to initiate investigations to identify occult vocal palsy in patients who present with pneumonia, who have a history of thyroid surgery.

Cost-effectiveness of intraoperative nerve monitoring in avoidance of bilateral recurrent laryngeal nerve injury in patients undergoing total thyroidectomy

Background

Intraoperative nerve monitoring (IONM) provides dynamic neural information and is recommended for high-risk thyroid surgery. In this analysis, the cost-effectiveness of IONM in preventing bilateral recurrent laryngeal nerve (RLN) injury was investigated.

Methods

A Markov chain model was constructed based on IONM use. The base-case patient was defined as a 40-year-old woman presenting with a 4·1-cm left-sided papillary thyroid cancer who developed RLN injury with loss of monitoring signal during planned bilateral thyroidectomy. It was hypothesized that, if the surgeon had used IONM, the RLN injury would have been detected and the operation would have been concluded as a thyroid lobectomy to avoid the risk of contralateral RLN injury. Cost in US dollars was converted to euros; probabilities and utility scores were identified from the literature and government resources. Length of follow-up was set as 20 years, and willingness-to-pay (WTP) as €38 000 (US $50 000) per quality-adjusted life-year (QALY).

Results

At the end of year 20, the not using IONM strategy accrued €163 995·40 (US $215 783·43) and an effectiveness of 14·15 QALYs, whereas use of the IONM strategy accrued €170 283·68 (US $224 057·48) and an effectiveness of 14·33 QALYs. The incremental cost–effectiveness ratio, comparing use versus no use of IONM, was €35 285·26 (US $46 427·97) per QALY, which is below the proposed WTP, indicating that IONM is the preferred and cost-effective management plan. A Monte Carlo simulation test that considered variability of the main study factors in a hypothetical sample of 10 000 patients showed IONM to be the preferred strategy in 85·8 per cent of the population.

Conclusion

Use of IONM is cost-effective in patients undergoing bilateral thyroid surgery.

Paclitaxel inhibits post-traumatic recurrent laryngeal nerve regeneration into the posterior cricoarytenoid muscle in a canine model

OBJECTIVES/HYPOTHESIS

To investigate the efficacy of paclitaxel, a potent microtubule inhibitor with a more favorable therapeutic index as compared with vincristine, in preventing post-traumatic nerve regeneration of the recurrent laryngeal nerve into the posterior cricoarytenoid muscle in a canine laryngeal model.

STUDY DESIGN

Experimental animal study.

METHODS

Forty-nine canine hemilaryngeal specimens were divided into five experimental groups. Under general anesthesia, a tracheostomy, recurrent laryngeal nerve (RLN) transection and repair, and laryngeal adductory pressures (LAP) were measured pre-RLN injury. The approach to the posterior cricoarytenoid (PCA) muscle for neurotoxin injection was transoral or open transcervical, at 0 or 3 months. At 6 months, postinjury LAPs were measured and the animals were sacrificed at 6 months to allow for laryngeal harvesting and analysis.

RESULTS

Paclitaxel demonstrated increased mean laryngeal adductory pressures (70.6%) as compared with saline control (55.5%). The effect of paclitaxel was the same as observed with vincristine at 0 months and with a delayed injection at 3 months. There was no difference between transoral or open injection groups.

CONCLUSIONS

PCA muscle injection with paclitaxel resulted in improved strength of laryngeal adduction. This effect was similar to that of vincristine at both 0 and 3 months following nerve injury. A single intramuscular injection of paclitaxel was well tolerated. Additional human studies are needed to determine the degree of clinical benefit of this intervention.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:651-655, 2017.

Intraoperative Neurophysiological Monitoring of the Laryngeal Nerves During Anterior Neck Surgery: A Review

Contributions to the literature on intraoperative neuro monitoring (IONM) during endocrine and head and neck surgery have increased over recent years. Organizational support for neural monitoring during surgery is becoming evident and is increasingly recognized as an adjunct to visual nerve identification. A comprehensive understanding of the role of IONM for prevention of nerve injuries is critical to maximize safety during surgery of the anterior compartment of the neck. This review will explore the potential advantages of IONM to improve the outcomes among patients undergoing anterior neck surgery.

Compound Motor Action Potential Quantifies Recurrent Laryngeal Nerve Innervation in a Canine Model

Objective:

The compound motor action potential (CMAP) is the summated action potential from multiple muscle fibers activated by a single nerve impulse. The utility of laryngeal muscle CMAP for quantifying innervation following recurrent laryngeal nerve (RLN) injury was investigated.

Method:

In a series of 21 canine hemi-laryngeal preparations, RLNs were exposed and a stimulating electrode placed. Maximum CMAP amplitudes and area under the curve from the thyroarytenoid (TA) muscles were obtained at baseline and at 6 months following injury to the RLN. Injury mechanisms included crush, stretch, cautery, and complete transection with microsuture repair.

Results:

Prior to injury, baseline CMAP amplitudes and area under the curve were 15.81 mV and 15.49mVms, respectively. Six months following injury, CMAP amplitude and area under curve were 105.1% and 102.1% of baseline for stretch, 98.7% and 112.7% for crush, 93.3% and 114.3% for cautery. The CMAP amplitude and area under the curve in the transection/repair group had a 54.3% and 69.4% recovery, respectively, which were significantly different than baseline ( P < .01, P < .05). These values were correlated with vocal fold motion.

Conclusion:

The CMAP is a measure of vocal fold innervation. The technique could be further developed for clinical and experimental applications.

[Surgical assessment of complications after thyroid gland operations]

BACKGROUND

The extent, magnitude and technical equipment used for thyroid surgery has changed considerably in Germany during the last decade. The number of thyroidectomies due to benign goiter have decreased while the extent of thyroidectomy, nowadays preferentially total thyroidectomy, has increased. Due to an increased awareness of surgical complications the number of malpractice claims is increasing.

OBJECTIVES

In contrast to surgical databases the frequency of complications in malpractice claims reflects the individual impact of complications on the quality of life. In contrast to surgical databases unilateral and bilateral vocal fold palsy are therefore at the forefront of malpractice claims. As guidelines are often not applicable for the individual surgical expert review, the question arises which are the relevant criteria for the professional expert witness assessing the severity of the individual complication.

RESULTS

While in surgical databases major complications after thyroidectomy, such as vocal fold palsy, hypoparathyroidism, hemorrhage and infections are equally frequent (1-3 %), in malpractice claims vocal fold palsy is significantly more frequent (50 %) compared to hypoparathyroidism (15 %), hemorrhage and infections (about 5 % each). To avoid bilateral nerve palsy intraoperative nerve monitoring has become of utmost importance for surgical strategy and malpractice suits alike. For surgical expert review documentation of individual risk-oriented indications, the surgical approach and postoperative management are highly important.

CONCLUSION

Guidelines only define the treatment corridors of good clinical practice. Surgical expert reviews in malpractice suits concerning quality of care and causality between surgical management, complications and sequelae of complications are therefore highly dependent on the grounds and documentation of risk-oriented indications for thyroidectomy, intraoperative and postoperative surgical management.

Head injury patient with bilateral vocal cord paralysis: a mistake and a lesson learnt

Bilateral recurrent nerve palsy along with head injury is a rare clinical possibility and can be potentially fatal if not properly diagnosed. We report a case of a head injury patient with intact Glasgow Coma Scale requiring immediate re-intubation and tracheostomy after extubation failure as a result of stridor and severe dyspnoea with paradoxical respiratory pattern, possibly because of undiagnosed significant surgical history.

Epidemiology of vocal fold paralyses after total thyroidectomy for well-differentiated thyroid cancer in a Medicare population

OBJECTIVES

The population-level incidence of vocal fold paralysis after thyroidectomy for well-differentiated thyroid carcinoma (WDTC) is not known. This study aimed to measure longitudinal incidence of postoperative vocal fold paralyses and need for directed interventions in the Medicare population undergoing total thyroidectomy for WDTC.

STUDY DESIGN

Retrospective cohort study.

SETTING

US population.

SUBJECTS AND METHODS

Subjects were Medicare beneficiaries. SEER-Medicare data (1991-2009) were used to identify beneficiaries who underwent total thyroidectomy for WDTC. Incident vocal fold paralyses and directed interventions were identified. Multivariate analyses were used to determine factors associated with odds of developing these surgical complications.

RESULTS

Of 5670 total thyroidectomies for WDTC, 9.5% were complicated by vocal fold paralysis (8.2% unilateral vocal fold paralysis [UVFP]; 1.3% bilateral vocal fold paralysis [BVFP]). Rate of paralyses decreased 5% annually from 1991 to 2009 (odds ratio 0.95; 95% confidence interval, 0.93-0.97; P < .001). Overall, 22% of patients with vocal fold paralysis required surgical intervention (UVFP 21%, BVFP 28%). Multivariate logistic regression revealed that the odds of postthyroidectomy paralysis increased with each additional year of age, with non-Caucasian race, with particular histologic types, with advanced stage, and in particular registry regions.

CONCLUSION

Annual rates of postthyroidectomy vocal fold paralyses are decreasing among Medicare beneficiaries with WDTC. High incidence in this aged population is likely due to a preponderance of temporary paralyses, which is supported by the need for directed intervention in less than a quarter of affected patients. Further population-based studies are needed to refine the population incidence and risk factors for paralyses in the aging population.

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.