Meta-analysis evaluating resting laryngeal endoscopy as a diagnostic tool for recurrent laryngeal neuropathy in the equine athlete.

BACKGROUND: Resting endoscopy has commonly been used as a method to predict laryngeal function at exercise. OBJECTIVES: To perform a meta-analysis to determine the sensitivity and specificity of resting laryngeal endoscopy to predict clinical recurrent laryngeal neuropathy at exercise. STUDY DESIGN: Meta-analysis. METHODS: Manuscripts were included if data were available for both resting and exercising airway function on all or a subset of horses. Normal resting endoscopy was defined as laryngeal grades 1 or 2 on a 4-/7-point scale or 1, 2 or 3 on a 5-point scale and normal dynamic endoscopy as a dynamic laryngeal grade A. RESULTS: Twelve studies including 1827 horses were evaluated. A small proportion of horses with grade 1 or grade 2 laryngeal function at rest, 3.5 and 11.9%, respectively, were identified as having abnormal laryngeal function at exercise. Within the horses with grade 3 laryngeal function at rest, 16% were classified as grade A, 26.4% as grade B and 57.6% as grade C at exercise. Worsening subgrades within resting grade 3 demonstrated an increasing proportion of complete or partial paralysis at exercise. The sensitivity and specificity of resting endoscopy was 74.4 and 95.1%, respectively, and the positive and negative predictive values were 85.6 and 90.5% respectively. MAIN LIMITATIONS: Use of two separate grading systems for evaluating resting laryngeal function. Other forms of dynamic airway collapse were not evaluated. CONCLUSIONS: Resting endoscopy is sensitive and highly specific for predicting laryngeal function at exercise. Dynamic endoscopy is important to assess multiple causes of airway collapse.

Ipsilateral nonrecurrent laryngeal nerve palsy and delayed palsy of the contralateral recurrent laryngeal nerve in a case of third-time reoperative thyroid surgery.

The occurrence of nonrecurrent laryngeal nerve and delayed nerve palsy of the contralateral nerve occurring simultaneously has never been described. A 67-year-old woman underwent reoperative completion thyroidectomy for enlarging thyroid nodules with recurrent hyperthyroidism and obstructive symptoms. Preoperative computed tomography of the neck showed a large compressive goitre with an aberrant right subclavian artery. At surgery, a type 1 nonrecurrent laryngeal nerve was found and inadvertently transected due to dense adhesions. It was repaired with ansa cervicalis graft. A fully preserved and functional recurrent laryngeal nerve was seen on the contralateral side at the end of surgery. However, the patient developed a delayed palsy on day 4 of the recurrent laryngeal nerve requiring a tracheostomy. Following successful speech and swallowing therapy, the patient was decannulated with good phonation and recovery of the left cord. Patients are at risk of bilateral nerve injury and late onset palsy in reoperative thyroid surgery. Management can be challenging and should be recognised to ensure appropriate therapy.

Pharyngolaryngeal symptoms associated with thyroid disease.

PURPOSE OF REVIEW: The current review summarizes previous reports on laryngopharyngeal symptoms associated with thyroid disease. This review also includes pharyngolaryngeal symptoms caused by thyroidectomy. However, we focus on pharyngolaryngeal symptoms following uncomplicated thyroidectomy, as this is an important issue in the fields of otolaryngology. RECENT FINDINGS: An enlarged thyroid gland, as in thyroiditis, multinodular goiter, or large nodules, can cause compressive symptoms. Malignant nodules invading the recurrent laryngeal nerve and benign nodules compressing the nerve can cause vocal cord paralysis and hoarseness. Pharyngolaryngeal symptoms are known to develop after a thyroidectomy, generally as a result of injury to the superior or recurrent laryngeal nerve. However, recent studies have shown that various pharyngolaryngeal symptoms, such as globus symptoms and voice changes, occur after thyroidectomy in the absence of laryngeal nerve injury. These symptoms are known collectively as postthyroidectomy syndrome. Several possible explanations have been proposed and evaluated for postthyroidectomy syndrome. SUMMARY: Several thyroid disorders can cause compressive symptoms and hoarseness. Superior and/or recurrent laryngeal nerve injury during thyroidectomy is the main cause of various pharyngolaryngeal symptoms. However, other pharyngolaryngeal symptoms that arise following thyroidectomy in the absence of nerve injury, a condition known as postthyroidectomy syndrome, are becoming more common.

Laryngeal electromyographic changes in postthyroidectomy patients with normal vocal cord mobility.

Thyroidectomy has been used for the treatment of thyroid disease for more than 100 years. In spite of the advancement of surgical techniques, there is still a risk of laryngeal nerve injury. The risk of partial or complete injury still depends on some surgical and disease-related factors. The aim of this study is to show the partial injury and to establish these risk factors via laryngeal electromyographic analysis (LEMG) in postthyroidectomy patients with normal vocal cord motion and mucosal anatomy. Patients who had undergone thyroid surgery were enrolled in this prospective study. LEMG analysis was performed to all patients with normal vocal cord mobility preoperatively and was repeated after the first and the third months of surgery. Thyroarytenoid (TA) and cricothyroid (CT) muscles were used to evaluate recurrent and external branch of superior laryngeal nerves, respectively. Four of the 32 patients had mild-to-moderate degrees of partial LEMG changes during preoperative LEMG analysis of TA and CT muscles on each side. After 3 months of surgery, there was a statistically significant worsening of LEMG findings in the right and left external branches of superior and left recurrent laryngeal nerves. Disease and surgery-related risk factors were analyzed. However, there was no significant relationship on the progression of LEMG findings according to these parameters. This is the first prospective study which supports the risk of progression of LEMG changes in patients with normal laryngoscopic examination after thyroid surgery. No reliable significant risk factor was found influencing the LEMG progression.

Transoesophageal ultrasound and computer tomographic assessment of the equine cricoarytenoid dorsalis muscle: Relationship between muscle geometry and exercising laryngeal function.

REASONS FOR PERFORMING STUDY: Early detection of recurrent laryngeal neuropathy (RLN) is of considerable interest to the equine industry. OBJECTIVES: To describe two imaging modalities, transoesophageal ultrasound (TEU) and computed tomography (CT) with multiplanar reconstruction to assess laryngeal muscle geometry, and determine the relationship between cricoarytenoid dorsalis (CAD) geometry and function. STUDY DESIGN: Two-phase study evaluating CAD geometry in experimental horses and horses with naturally occurring RLN. METHODS: Equine CAD muscle volume was determined from CT scan sets using volumetric reconstruction with LiveWire. The midbody and caudal dorsal-ventral thickness of the CAD muscle was determined using a TEU in the same horses; and in horses with a range of severity of RLN (n = 112). RESULTS: Transoesophageal ultrasound was able to readily image the CAD muscles and lower left:right CAD thickness ratios were observed with increasing disease severity. Computed tomography based muscle volume correlated very closely with ex vivo muscle volume (R2 = 0.77). CONCLUSIONS: Computed tomography reconstruction can accurately determine intrinsic laryngeal muscle geometry. A relationship between TEU measurements of CAD geometry and laryngeal function was established. These imaging techniques could be used to track the response of the CAD muscle to restorative surgical treatments such as nerve muscle pedicle graft, nerve anastomosis and functional electrical stimulation.

Is intraoperative neural monitoring necessary for exploration of the superior laryngeal nerve?

BACKGROUND: We aimed to evaluate the contribution of intraoperative neuromonitoring to the visual and functional identification of the external branch of the superior laryngeal nerve and the effect on postoperative voice changes. METHODS: The prospective data of 221 patients (183 women, 38 men) who underwent thyroid operation with intraoperative neuromonitoring for exploration of the external branch of the superior laryngeal nerve were evaluated retrospectively. The surface endotracheal tube-based Medtronic NIM3 (Medtronic, Jacksonville, FL) intraoperative neuromonitoring device was used. The function of the external branch of the superior laryngeal nerve was evaluated by cricothyroid muscle twitch. Additionally, the contribution of the external branch of the superior laryngeal nerve to vocal cord adduction was evaluated using electromyographic records. RESULTS: A total of 374 (95.2%) of 393 external branch of the superior laryngeal nerves were identified; 145 (36.9%) external branch of the superior laryngeal nerves were identified visually before being stimulated with a probe, and 130 (33.1%) external branch of the superior laryngeal nerves were identified visually after being identified with a probe. Although 99 (25.2%) external branch of the superior laryngeal nerves were identified with a probe, they were not visualized. Intraoperative neuromonitoring provided meaningful contributions to visual (P = .001) and functional (P = .001) identification of the external branch of the superior laryngeal nerve. Positive electromyographic responses were recorded from 257 external branch of the superior laryngeal nerves (68.7%). After the patients with recurrent laryngeal nerve palsy were excluded, voice changes were detected in 6 (3.3%) of 184 patients with identified external branch of the superior laryngeal nerves and 3 (20%) of 15 patients in whom at least 1 external branch of the superior laryngeal nerve could not be identified with intraoperative neuromonitoring. CONCLUSION: Intraoperative neuromonitoring provided an important contribution to the visual and functional identification of the external branch of the superior laryngeal nerve. Intraoperative neuromonitoring is a helpful adjunct for identifying the external branch of the superior laryngeal nerve.

Lesión bilateral del nervio laríngeo recurrente en tiroidectomía total con o sin neuromonitorización intraoperatoria. Revisión sistemática y metaanálisis / Bilateral recurrent laryngeal nerve injury in total thyroidectomy with or without intraoperative neuromonitoring. Systematic review and meta-ana

Introducción y objetivo: El riesgo de parálisis laríngea bilateral (PLB) tras tiroidectomía total (TT) es bajo pero una de las mayores preocupaciones del cirujano y un incidente de seguridad grave que puede comprometer la vía aérea, precisar reintubación o traqueotomía y provocar secuelas graves o la muerte. No se ha demostrado que la neuromonitorización (NM) como herramienta diagnóstica precoz de lesión del nervio laríngeo recurrente (NLR) reduzca el riesgo. Objetivo: estimar el riesgo de PLB con y sin NM en TT mediante revisión sistemática y metaanálisis. Método: Revisión sistemática de ensayos clínicos, estudios de cohortes y series de casos de TT con y sin NM publicados en el periodo 2000-2014 en PubMed, Scopus (EMBASE) y Cochrane Library. Se exploró la heterogeneidad entre estudios y se estimaron riesgos ponderados agrupados siguiendo modelos de efectos aleatorios. Resultados: Se seleccionaron 40 artículos con estimaciones del riesgo en 54 series (25 sin NM, 29 con NM) con 30.922 pacientes. La incidencia de PLB con NM resultó inferior que sin NM (2,43‰, [1,55-3,5‰] versus 5,18‰, [2,53-8,7‰]). Esta diferencia equivale a una reducción absoluta del riesgo de 2,75‰ y un número necesario de pacientes a tratar de 364,13. El grupo con NM resultó más homogéneo (I2 = 7,52%) que sin NM (I2 = 79,32%). Las diferencias del análisis por subgrupos fueron imprecisas por el escaso número de parálisis. Conclusiones: El riesgo de PLB es menor en los estudios con neuromonitorización (AU)

Introduction and Objective: The risk of producing bilateral laryngeal paralysis (BLP) in total thyroidectomy (TT) is low, but it is a concern for the surgeon and a serious safety incident that may compromise the airway, require reintubation or tracheostomy and cause serious sequelae or death. Neuromonitoring (NM), as an early diagnostic tool for the existence of injury to the recurrent laryngeal nerve (RLN), has not been shown to have reduced the risk, even though published series show lower incidences. Our objective was to estimate the risk of bilateral RLN paralysis with and without NM TT by systematic review and meta-analysis. Method: We performed a systematic review of clinical trials, cohort studies and case series with total thyroidectomy without NM published in the period 2000-2014. A database search was performed using PubMed, Scopus (EMBASE) and the Cochrane Library. Heterogeneity between studies was explored and weighted risks grouped according to random effects models were estimated. Results: We selected 40 articles and estimates of risk were identified in 54 case series (without NM, 25; with NM, 29) with 30,922 patients. The prevalence of BLP in the series with NM was lower compared to that without NM (2.43‰, [1.55 to 3.5‰] versus 5.18‰ [2.53 to 8.7‰]). This difference is equivalent to an absolute risk reduction of 2.75‰ with a number needed to treat of 364.13. The NM group was more homogeneous (I2 = 7.52%) than those without NM (I2 = 79.32%). The observed differences in the subgroup analysis were very imprecise because the number of observed paralysis was very low. Conclusions: The risk of bilateral paralysis is lower in studies with neuromonitoring (AU)

EBSLN and Factors Influencing its Identification and its Safety in Patients Undergoing Total Thyroidectomy: A Study of 456 Cases.

BACKGROUND: The external branch of the superior laryngeal nerve (EBSLN) is at surgical risk during superior thyroid pole ligation during thyroidectomy. Majority of studies have addressed the identification of these nerves and its reported incidence. Very few studies have addressed the relationship of these nerves with the volume of the thyroid gland and presence of toxicity. MATERIALS AND METHODS: A retrospective evaluation of 456 patients who underwent total thyroidectomy were analysed from the prospectively maintained database. The EBSLN was diligently identified and preserved before individual ligation of the superior thyroid pedicle. The nerve was graded as per the Cernea classification (type I, IIa and IIb). Goitres are classified into toxic & non-toxic based on hyperthyroidism, further sub classified as large (>50 cc) and small (≤50 cc) based on volume of each lobe. The grading of EBSLN was correlated with hyperthyroidism and volume of each lobe. RESULTS: In 456 patients (912 nerves), EBSLN was identified in 849/912(93.09%), type I in 156/912(17.1%), type IIa in 522/912(57.23%) and type IIb in 171/912(18.75%). The prevalence of large goitres was 180/912(19.73%).Type IIb nerve was predominantly seen in 161/180(89.4%) of large goitres. Type IIb nerves was more common in toxic 141/372(37.9%) than non-toxic lobes 25/540(5.46%). CONCLUSION: Large goitres are not uncommon in toxic cases. The EBSLN is at highest risk of injury in this subgroup of patients and surgical expertise is essential to identify this entity of EBSLN to perform a safe thyroidectomy.

International survey on the identification and neural monitoring of the EBSLN during thyroidectomy.

OBJECTIVES/HYPOTHESIS: Surgical management of the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy is complex. We hypothesized that there exist variations in surgical behaviors patterns in the management of the EBSLN during thyroidectomy. STUDY DESIGN: A prospective Web-based anonymous survey (www.surveymonkey.com). METHODS: The survey, consisting of 22 questions including surgeon demographics, laryngeal examination before and after surgery, and utilization of intraoperative neuromonitoring (IONM) for the management of the recurrent laryngeal nerve (RLN) and the EBSLN, was sent to 673 surgeons worldwide with known interest in thyroid surgery. RESULTS: A total of 170/673 (25.3%) surgeons from five continents with low-volume (11.2%), moderate-volume (27.2%), and high-volume practices (61.5%) completed the survey. Laryngeal preoperative examination was performed by 94% of respondents. IONM was utilized in the RLN management by 95% of respondents. IONM was used for identification of the EBSLN by 26.3% of low-volume versus 68.4% of high-volume surgeons (P = .004), and 93% of respondents felt EBSLN identification with IONM as necessary in voice professionals. Staged thyroidectomy was performed for benign disease by 89.5% of low-volume versus 63.2% of high-volume surgeons (P = .031). Post-thyroid surgery laryngeal examination was performed by 36.8% of low-volume versus 64.9% of high-volume surgeons (P = .032). CONCLUSIONS: Laryngeal examination and IONM is used frequently. However, the exact pattern of utilization varies notably with demographic information. Generally, high-volume surgeons, those with otolaryngology background, and younger surgeons more commonly utilize IONM according to existing international neural monitoring study group guidelines. Prospective multicenter studies are needed to guide an evidence-based management of the EBSLN during thyroidectomy.

Intraoperative neuromonitoring of the external branch of the superior laryngeal nerve during thyroidectomy: the need for evidence-based data and perioperative technical/technological standardization.

The external branch of the superior laryngeal nerve (EBSLN) is surgically relevant since its close anatomical proximity to the superior thyroid vessels. There is heterogeneity in the EBSLN anatomy and EBSLN damage produces changes in voice that are very heterogenous and difficult to diagnose. The reported prevalence of EBSLN injury widely ranges. EBSLN iatrogenic injury is considered the most commonly underestimated complication in endocrine surgery because vocal assessment underestimates such event and laryngoscopic postsurgical evaluation does not show standardized findings. In order to decrease the risk for EBSLN injury, multiple surgical approaches have been described so far. IONM provides multiple advantages in the EBSLN surgical approach. In this review, we discuss the current state of the art of the monitored approach to the EBSLN. In particular, we summarize, providing our additional remarks, the most relevant aspects of the standardized technique brilliantly described by the INMSG (International Neuromonitoring Study Group). In conclusion, in our opinion, there is currently the need for more prospective randomized trials investigating the electrophysiological and pathological aspects of the EBSLN for a better understanding of the role of IONM in the EBSLN surgery.

Superior laryngeal nerve injury: effects, clinical findings, prognosis, and management options.

PURPOSE OF REVIEW: The superior laryngeal nerve (SLN) provides motor innervation to the cricothyroid muscle. However, the functions of this muscle and the anatomic variations of the nerve that supplies it are not fully understood. SLN paresis and paralysis (SLNp) is difficult to diagnose because of a lack of consistent laryngeal findings, and its effects on the voice likely go beyond simple pitch elevation control. RECENT FINDINGS: Although SLNp has traditionally been thought to lead to voice pitch limitation, recent research findings reveal multiple roles for this nerve in voice and speech. Cricothyroid muscles are the primary controls of fundamental frequency of voice. SLNp can lead to significant contraction of pitch range, vocal fold vibratory phase asymmetry, and acoustic aperiodicity, thus leading to an overall poor vocal quality. In addition, cricothyroid muscles may also play a role in pitch lowering and shifting from voiced to unvoiced sounds during speech. SUMMARY: Subtle signs, symptoms, and diagnostic findings associated with SLNp make this disorder difficult to characterize clinically. Lack of treatment methodologies to restore the dynamic action of the cricothyroid muscles poses difficulties in treating patients with this condition. A more thorough understanding of the effects of SLNp will improve diagnosis and treatment.

Clinical practice guideline: improving voice outcomes after thyroid surgery.

OBJECTIVE: Thyroidectomy may be performed for clinical indications that include malignancy, benign nodules or cysts, suspicious findings on fine needle aspiration biopsy, dysphagia from cervical esophageal compression, or dyspnea from airway compression. About 1 in 10 patients experience temporary laryngeal nerve injury after surgery, with longer lasting voice problems in up to 1 in 25. Reduced quality of life after thyroid surgery is multifactorial and may include the need for lifelong medication, thyroid suppression, radioactive scanning/treatment, temporary and permanent hypoparathyroidism, temporary or permanent dysphonia postoperatively, and dysphagia. This clinical practice guideline provides evidence-based recommendations for management of the patient's voice when undergoing thyroid surgery during the preoperative, intraoperative, and postoperative period. PURPOSE: The purpose of this guideline is to optimize voice outcomes for adult patients aged 18 years or older after thyroid surgery. The target audience is any clinician involved in managing such patients, which includes but may not be limited to otolaryngologists, general surgeons, endocrinologists, internists, speech-language pathologists, family physicians and other primary care providers, anesthesiologists, nurses, and others who manage patients with thyroid/voice issues. The guideline applies to any setting in which clinicians may interact with patients before, during, or after thyroid surgery. Children under age 18 years are specifically excluded from the target population; however, the panel understands that many of the findings may be applicable to this population. Also excluded are patients undergoing concurrent laryngectomy. Although this guideline is limited to thyroidectomy, some of the recommendations may extrapolate to parathyroidectomy as well. RESULTS: The guideline development group made a strong recommendation that the surgeon should identify the recurrent laryngeal nerve(s) during thyroid surgery. The group made recommendations that the clinician or surgeon should (1) document assessment of the patient's voice once a decision has been made to proceed with thyroid surgery; (2) examine vocal fold mobility, or refer the patient to a clinician who can examine vocal fold mobility, if the patient's voice is impaired and a decision has been made to proceed with thyroid surgery; (3) examine vocal fold mobility, or refer the patient to a clinician who can examine vocal fold mobility, once a decision has been made to proceed with thyroid surgery if the patient's voice is normal and the patient has (a) thyroid cancer with suspected extrathyroidal extension, or (b) prior neck surgery that increases the risk of laryngeal nerve injury (carotid endarterectomy, anterior approach to the cervical spine, cervical esophagectomy, and prior thyroid or parathyroid surgery), or (c) both; (4) educate the patient about the potential impact of thyroid surgery on voice once a decision has been made to proceed with thyroid surgery; (5) inform the anesthesiologist of the results of abnormal preoperative laryngeal assessment in patients who have had laryngoscopy prior to thyroid surgery; (6) take steps to preserve the external branch of the surperior laryngeal nerve(s) when performing thyroid surgery; (7) document whether there has been a change in voice between 2 weeks and 2 months following thyroid surgery; (8) examine vocal fold mobility or refer the patient for examination of vocal fold mobility in patients with a change in voice following thyroid surgery; (9) refer a patient to an otolaryngologist when abnormal vocal fold mobility is identified after thyroid surgery; (10) counsel patients with voice change or abnormal vocal fold mobility after thyroid surgery on options for voice rehabilitation. The group made an option that the surgeon or his or her designee may monitor laryngeal electromyography during thyroid surgery. The group made no recommendation regarding the impact of a single intraoperative dose of intravenous corticosteroid on voice outcomes in patients undergoing thyroid surgery.

Initial experience using a bipolar radiofrequency ablation device for hemostasis during thyroidectomy.

BACKGROUND: The purpose of this study was to evaluate a novel bipolar radiofrequency ablation (BRFA) device using nanotechnology for division of all named vessels during thyroidectomy. METHODS: All thyroidectomies from January 2008 to July 2010 at a single institution used the BRFA device (EnSeal, Ethicon Endo-Surgery, Cincinnati, OH) for hemostasis. Clinicopathologic data and complications were recorded and compared with existing literature using other energy devices. RESULTS: Fifty-eight thyroidectomies were performed. Mean age was 54.7 years, and mean operating room time was 81 minutes. The average estimated blood loss was 46 mL. Ninety percent of patients were discharged in <23 hours. There were no hemorrhages. There was 1 recurrent laryngeal nerve (RLN) injury, and 1 case of transient hypocalcemia. CONCLUSION: This first small series using the BRFA device reveals initial safety and effectiveness for thyroid hemostasis, and warrants further study. The minimal thermal spread inherent in this device may make it an attractive option when structures such as the RLN may be near the zone of hemostasis.

A voice acoustic analysis of thyroid adenoma patients after a unilateral thyroid lobectomy.

OBJECTIVE: The objective of this study was to investigate the features of voice changes in thyroid adenoma patients secondary to a unilateral thyroid lobectomy that did not result in laryngeal nerve injury. STUDY DESIGN: Prospective study. METHODS: Pre- and postoperative fiberlaryngoscopic and voice acoustic analyses were performed on 32 adult patients (eight males and 24 females) with unilateral thyroid adenoma. Forty adults (20 women and 20 men) with normal voice function were grouped as controls. RESULTS: The vocal folds before and after surgery in all patients appeared to be normal under the fiberlaryngoscope. The preoperative voice was slightly abnormal in female patients and normal in male patients. One week after surgery, the F0 levels of both male and female patients decreased significantly from the values recorded before surgery (P<0.05). One month after the surgery, the F0 standard deviation, fundamental frequency perturbation, amplitude perturbation, noise/harmonic ratio, voice turbulence index, and degree of subharmonics in female patients decreased significantly from the values observed before surgery (P<0.05). Three months after surgery, the values of these indicators returned to normal. CONCLUSIONS: The preoperative voice was slightly abnormal in female patients and normal in male patients. After a unilateral thyroid lobectomy, which did not result in injury of the laryngeal nerve, the acoustic measures of male patients consequently became slightly abnormal and returned to normal within 1 month. The indicators of female patients improved from that demonstrated before surgery and returned to normal within 3 months.