Search Results (15)

Background: Intraoperative nerve monitoring (IONM) is increasingly recognized as an essential technique in thyroid surgery to preserve the integrity of the recurrent laryngeal nerve (RLN) and prevent postoperative complications. Although widely adopted, several technical and anesthetic factors can significantly affect the reliability and interpretation of electromyographic (EMG) signals. Methods: This narrative review summarizes the principles and methodologies of IONM in thyroid surgery, focusing on the mechanisms of RLN injury, the clinical benefits of IONM, and its limitations. Particular emphasis is placed on the anesthesiologic considerations, including the effects of neuromuscular blocking agents and anesthetic maintenance methods for EMG signal quality. Recent advances in alternative IONM techniques are also discussed. Results: IONM facilitates early detection of RLN injury and improves surgical outcomes. However, signal loss and technical errors occur in up to 23% of cases. Appropriate anesthetic management, such as the judicious use of neuromuscular blocking agents and the use of reversal agents like sugammadex, can significantly improve IONM accuracy. Alternative approaches, such as transcutaneous or thyroid cartilage electrode-based monitoring, show promise in overcoming current limitations. Conclusions: IONM is a valuable tool in modern thyroid surgery, aiding in the prevention of RLN injury. Anesthesiologists play a crucial role in optimizing IONM quality by managing factors that affect EMG signals. Ongoing research into novel monitoring techniques is expected to further enhance patient safety and surgical precision. Full article

Background and Objectives: Thyroid surgery with intraoperative neural monitoring (IONM) of the recurrent laryngeal nerve (RLN) requires precise anesthetic management. This narrative review compares non-selective (neostigmine) and selective (sugammadex) reversal agents for neuromuscular blockade (NMB), discussing their mechanisms of action and the challenges of achieving optimal NMB reversal without compromising surgical conditions or IONM quality. Materials and Methods: A literature search was conducted using PubMed, MEDLINE, and Google Scholar for studies published up to November 2023. Relevant case studies, clinical trials, systematic reviews, and guidelines focusing on NMB reversal in thyroid surgery with IONM were included, prioritizing investigations involving sugammadex and neostigmine. Results: Clinical evidence indicates that sugammadex (0.5–1 mg/kg) provides the rapid and reliable return of neuromuscular function, benefiting electromyography (EMG) signal quality preservation. However, overshooting the reversal can precipitate patient movement, compromising surgical precision. Neostigmine (0.03–0.04 mg/kg), while less selective, remains a cost-effective alternative, with recent studies suggesting adequate support for IONM signal integrity when carefully dosed and timed. Conclusions: This review underscores the need for balanced NMB reversal strategies tailored to intraoperative monitoring requirements in thyroidectomy. Further randomized trials and large-scale studies are needed to refine and standardize NMB reversal strategies in thyroid surgery with IONM. Full article

Background: Dysphonia, a common symptom after thyroid surgery, is most often caused by damage to the recurrent laryngeal nerve. Laryngeal electromyography (LEMG) is used as a qualitative diagnostic tool to distinguish neurological etiology from other causes of dysphonia. The purpose of this study is to establish the value of LEMG as a predictor factor in the recovery of unilateral recurrent paralysis post-thyroidectomy. Methods: This study included 11 patients with unilateral vocal fold palsy (UVFP) evidenced on the videostrobolaryngoscopy (VSL) after thyroidectomy. Electrical activity of thyroarytenoid (TA) muscles of the patients included in the study was recorded through LEMG and the prognosis of the lesions was classified as excellent, fair, or poor based on the presence of spontaneous activity and motor unit recruitment. Results: LEMG at the first clinic visit showed an excellent prognosis in three of the cases, a fair prognosis in three of the cases, and five of them indicated a poor prognosis. At 6 months after the first LEMG, patients with a poor prognosis were unchanged and showed no LEMG improvement. Those with an excellent prognosis showed an increased recruitment response, and LEMG was normal. In one patient with a fair prognosis and minimal spontaneous activity, LEMG recruitment decreased during reevaluation. The other two fair-prognosis patients had a normal LEMG. Conclusions: A correlation was found between LEMG findings and functional recovery of the vocal cords, demonstrating that the presence of spontaneous activity represents a negative prognostic factor. However, due to limited patient cohorts, the sensitivity of the LEMG as a prognostic tool in the functional recovery of the larynx is not yet established and requires further research. Full article

Background/Objectives: Anesthesia plays a very important role in the successful management of intraoperative neuromonitoring (IONM). The aim of our study was to investigate the impact of anesthesia induction and maintenance on the quality of signals during surgeries on the thyroid and parathyroid glands using neuromonitoring. Methods: The study included 72 patients who underwent surgery with IONM for one year. All the patients were intubated using a Glidescope videolaryngoscope with a hyperangulated blade. Two different approaches were used to facilitate intubation: succinylcholine-1 mg/kg and rocuronium bromide-0.3 mg/kg. For anesthesia maintenance, total intravenous anesthesia (TIVA) or combined anesthesia was used. Patients’ body movements during operations, as well as electromyography signals from the vagus and recurrent laryngeal nerves before resection, were recorded as V1 and R1. Results: Intraoperative unwanted movements were recorded in 25% of patients. Undesired movements were more frequently recorded in the TIVA group compared to the combined anesthesia group (p < 0.001) as well as in patients who received succinylcholine compared to patients who received rocuronium bromide (p = 0.028). Type of anesthesia maintenance as well as type of muscle relaxant did not affect the quality of recorded nerve signals. (p = 0.169 and p = 0.894, respectively). Conclusions: The type of muscle relaxant used significantly affects the occurrence of undesirable movements during thyroid surgery with IONM, while the type of anesthesia maintenance did not influence either the quality of the obtained signal or the occurrence of undesirable movements. Full article

Objective: This paper reviews the current literature about epidemiology, etiologies, diagnosis, and management of pediatric bilateral vocal fold paralysis (PBVFP). Methods: According to PRISMA statements, a narrative review of the current literature was conducted through the PubMed, Scopus, and Cochrane Library databases about the epidemiology, etiologies, diagnosis, and management of PBVFP. Results: PBVCP is the second most common congenital laryngeal anomaly in the pediatric population, accounting for 10% to 20% of pediatric laryngeal conditions. PBVCP is related to idiopathic (42.2%), congenital (19.7%), and neurological (16.9%) conditions. A tracheotomy is required in 60% of cases regarding stridor and dyspnea, which are the most prevalent symptoms. The diagnosis is based on the etiological features, clinical presentation, laryngoscopic findings, and objective examinations. Laryngeal electromyography may be used to support the diagnosis in difficult cases, but its reliability depends on the practitioner’s experience. The primary differential diagnosis is posterior glottis stenosis, which needs to be excluded regarding therapeutic and management differences with PBVCP. Transient surgical procedures consist of tracheotomy or laterofixation of the vocal fold. Current permanent procedures include uni- or bilateral partial arytenoidectomy, posterior transverse cordotomy, cricoid splits, and laryngeal selective reinnervation. There is no evidence of the superiority of some procedures over others. Conclusions: PBVCP is the second most common laryngeal disorder in the pediatric population. Diagnosis is based on etiological and clinical findings and may require the use of laryngeal electromyography. Therapeutic management may involve several transient or permanent surgical procedures that are associated with overall subjective improvements in symptoms, laryngeal findings, and low complication rates. Full article

Objective: Our objective is the description of the technique of vagus nerve stimulation in carotid triangle in order to monitor the recurrent laryngeal nerve (RLN) during thyroid and parathyroid surgery. Methods: We stimulated the vagus nerve in the carotid triangle during 150 thyroid or parathyroid surgeries using a monopolar electromyography electrode inserted under the mastoid process towards the jugular foramen as a cathode, and using another subdermal electrode in the mastoid as an anode. Another complementary method of vagus stimulation was achieved with a pair of subdermal electrodes, placing the cathode at the mandibular angle and the anode at the mastoid. Results: In all patients, compound muscle action potential (CMAP) was recorded in the vocal cords with both stimulation techniques, allowing semi-continuous monitoring to be carried out. Intraoperative lesions were detected in 16 of the cases; 9 of them were transient with CMAP recovery achieved when modifying surgical maneuvers. Conclusions: Vagus nerve stimulation in the carotid triangle is a reliable technique for monitoring the RLN in thyroid surgery. Vagus nerve stimulation in the carotid triangle is effective and safe for RLN monitoring, and it is a clear alternative to direct continuous stimulation of the nerve that by contrast requires its dissection in the carotid sheath. Full article

The purpose of this case series report is to demonstrate the current state of the art regarding tracheal intubation of an evoked electromyography-endotracheal tube (EMG-ET tube) for continuous intraoperative recurrent laryngeal nerve monitoring (IONM) in patients undergoing thyroid surgery. Both direct laryngoscopy (DL) and videolaryngoscopy (VL) are popular for routine tracheal intubation of an EMG-ET tube. A new intubating technique (styletubation), using a video-assisted intubating stylet (VS), provides less traumatic and swift intubation. Styletubation combined with VL ensures the precise placement of the EMG-ET tube. This novel intubation technique improves the outcome of intubating an EMG-ET tube for IONM. Full article

Intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) has been shown in adults to minimize nerve palsy after thyroid surgery, but only few studies on its efficacy in a pediatric population have been reported. We conducted a retrospective study on patients operated for thyroid lesions from 2016 to 2022. The analyzed population was divided in two groups: patients treated from 2016 to 2020, when the identification of the RLN was performed without IONM (Group A); and patients treated since 2021, when IONM was implemented in every surgical procedure on the thyroid (Group B). Intraoperative Neurophysiological Monitoring was performed by using corticobulbar motor-evoked potentials and continuous electromyography. Twentyfive children underwent thyroid resection, 19 (76%) of which due to thyroid carcinoma. Each patient’s recurrent nerve was identified; IONM was used in 13 patients. In Group A, one temporary nerve palsy was identified postoperatively (8.3%), while in group B one nerve dysfunction occurred (7.7%). No statistically significant difference was found between the two groups in terms of post-operative RLN palsy. No surgical complication due to the use of IONM was reported. In children and teenagers, intraoperative neuromonitoring of the recurrent laryngeal nerve is a safe and accurate method, minimizing the risk of nerve damage. Full article

Unilateral vocal fold paralysis (UVFP) causes glottal incompetence and poor vocal efficiency. The influence of laryngeal neuromuscular control on aerodynamics in UVFP remains unclear. This study investigated the relationship between laryngeal muscle activities using quantitative laryngeal electromyography (LEMG) and aerodynamics in UVFP. This prospective study recruited patients with UVFP, and the diagnosis was confirmed with videolaryngostroboscopy and LEMG. The patient received aerodynamic assessment and LEMG of the thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex and the cricothyroid (CT) muscle. The relationship between quantitative LEMG and aerodynamic parameters was analyzed. A total of 134 UVFP patients without concurrent CT muscle involvement were enrolled. Compared with the normal side, the peak turn frequency of the lesioned side was lower in the TA-LCA (p < 0.001) and CT (p = 0.048) muscles. Stepwise linear regression revealed that the turn ratio of TA-LCA muscles was a robust factor in the decrease in peak expiratory airflow (β = −0.34, p = 0.036), mean airflow during voicing (β = −0.28, p = 0.014), and aerodynamic power (β = −0.42, p = 0.019), and an increase in aerodynamic efficiency (β = 27.91, p = 0.012). In addition, the turn ratio of CT muscles was a potent factor in inducing an increase in aerodynamic resistance (β = 14.93, p = 0.029). UVFP without CT involvement still showed suppression of CT muscles on the lesioned side, suggesting that neurological impairment of the TA-LCA complex could cause asymmetrical compensation of CT muscles, further impeding aerodynamics. The residual function of TA-LCA muscle complexes facilitates less air leakage and power dissipation, enhancing aerodynamic efficiency. On the other hand, the symmetrical compensation of the CT muscles improves aerodynamic resistance. Full article

Laryngeal dystonia (LD), or spasmodic dysphonia (SD), is a chronic, task-specific, focal movement disorder affecting the larynx. It interferes primarily with the essential functions of phonation and speech. LD affects patients’ ability to communicate effectively and significantly diminishes their quality of life. Botulinum neurotoxin was first used as a therapeutic agent in the treatment of LD four decades ago and remains the standard of care for the treatment of LD. This article provides an overview of the clinical application of botulinum neurotoxin in the management of LD, focusing on the classification for this disorder, its pathophysiology, clinical assessment and diagnosis, the role of laryngeal electromyography and a summary of therapeutic injection techniques, including a comprehensive description of various procedural approaches, recommendations for injection sites and dosage considerations. Full article

In this cross-sectional study, we compared voice tone and activities relating to the laryngeal muscle between unilateral vocal fold paralysis (UVFP) patients with and without cricothyroid (CT) muscle dysfunction to define how CT dysfunction affects language tone. Eighty-eight female surgery-related UVFP patients were recruited and received acoustic voice analysis and laryngeal electromyography (LEMG) when the patient was producing the four Mandarin tones. The statistical analysis was compared between UVFP patients with (CT+ group, 17 patients) and without CT muscle (CT− group, 71 patients) involvement. When producing Mandarin Tone 2, the voice tone in the CT+ group had smaller rise range (p = 0.007), lower rise rate (p = 0.002), and lower fundamental frequency (F0) at the offset point of the voice (p = 0.023). When producing Mandarin Tone 4, the voice tone in the CT+ group had smaller drop range (p = 0.019), lower drop rate (p = 0.005), and lower F0 at voice onset (p = 0.025). The CT+ group had significantly lower CT muscle activity when producing the four Mandarin tones. In conclusion, CT dysfunction causes a limitation of high-rising tone in Tone 2 and high-falling tone in Tone 4, a property that dramatically limits the tonal characteristics in Mandarin, a tonal language. This limitation could further impair the patient’s communication ability. Full article

(1) Background: Laryngeal electromyography (LEMG) plays a key role in classifying the severity of nerve damage and determining the prognosis of the nerve recovery. LEMG is primarily a qualitative study, without a standardized approach to interpretation. The development of qualitative and quantitative analysis would situate LEMG in the gold standard of modern neurolaryngologic diagnostics. The aim of this study was to quantitatively evaluate laryngeal electromyography recorded in patients with vocal fold immobility or dysmobility. (2) Methods: The electromyographic material comprised 84 thyroarytenoid muscles recordings of 42 patients. (3) Results: In our study, we observed significant differences between EMG characteristics of healthy and paralyzed VF. Our study showed that recording laryngeal muscle activity during successive phases of breathing provides additional valuable information. We noticed that the frequency and amplitude of motor unit potentials correlates with the return of vocal fold functionality. (4) Conclusions: Laryngeal EMG guides the clinician on the best course of treatment for the patient. It is therefore important to develop an effective methodology and consensus on the quantitative interpretation of the record. Amplitude and frequency parameters are valuable in predicting neural recovery and in the return of vocal fold mobility. Full article

The use of transcartilage (TC) intraoperative neuromonitoring (IONM) in a pediatric population has not been reported. This study evaluated the feasibility and the benefit of using TC-IONM for thyroid cancer surgery in a pediatric population. This retrospective single-center study enrolled 33 pediatric patients who had received an IONM-assisted thyroidectomy. Demographic characteristics, standardized IONM laryngeal examinations and stimulation information (L1-V1-R1-R2-V2-L2) were compared between endotracheal tube (ET) and TC methods. In the 15 cancer patients (30 nerves), TC-IONM provided significant higher electromyography (EMG) amplitude (p < 0.001), signal stability (lower V1/V2 signal correlation, r = 0.955 vs. r = 0.484, p = 0.004), signal quality (higher ratio of V1 or V2 amplitude <500 µV, 0.0% vs. 43.8%, p = 0.005) and lower R1-R2p change (7.1% vs. 37.5%, p = 0.049) compared to ET-IONM. In the 18 benign patients (28 nerves), TC-IONM provided significantly higher EMG amplitude (p < 0.001), signal stability (r = 0.945 vs. r = 0.746, p = 0.0324) and non-significant higher signal quality and R1-R2p change. This report is the first to discuss the use of TC-IONM in pediatric thyroid surgery. In contrast with ET-IONM, TC-IONM had superior amplitude, stability and quality of EMG signals, which greatly facilitates the meticulous recurrent laryngeal nerve dissection in pediatric thyroidectomies. The TC-IONM method can be considered a feasible, effective and preferable method of monitored thyroidectomy in pediatric thyroid cancer. Full article

Background: A widely used method for assessing swallowing dysfunction is the videofluoroscopic swallow study (VFSS) examination. However, this method has a risk of radiation exposure. Therefore, using wearable, non-invasive and radiation-free sensors to assess swallowing function has become a research trend. This study addresses the use of a surface electromyography sensor, a nasal airflow sensor, and a force sensing resistor sensor to monitor the coordination of respiration and larynx movement which are considered the major indicators of the swallowing function. The demand for an autodetection program that identifies the swallowing patterns from multiple sensors is raised. The main goal of this study is to show that the sensor-based measurement using the proposed detection program is able to detect early-stage swallowing disorders, which specifically, are useful for the assessment of the coordination between swallowing and respiration. Methods: Three sensors were used to collect the signals from submental muscle, nasal cavity, and thyroid cartilage, respectively, during swallowing. An analytic swallowing model was proposed based on these sensors. A set of temporal parameters related to the swallowing events in this model were defined and measured by an autodetection algorithm. The verification of this algorithm was accomplished by comparing the results from the sensors with the results from the VFSS. A clinical application of the long-term smoking effect on the swallowing function was detected by the proposed sensors and the program. Results: The verification results showed that the swallowing patterns obtained from the sensors strongly correlated with the laryngeal movement monitored from the VFSS. The temporal parameters measured from these two methods had insignificant delays which were all smaller than 0.03 s. In the smoking effect application, this study showed that the differences between the swallowing function of smoking and nonsmoking participants, as well as their disorders, is revealed by the sensor-based method without the VFSS examination. Conclusions: This study showed that the sensor-based non-invasive measurement with the proposed detection algorithm is a viable method for temporal parameter measurement of the swallowing function. Full article

Oropharyngeal dysphagia (OPD) involves difficulty during one or more of the stages of swallowing, resulting in difficulty moving the bolus from the mouth to the stomach. A deficit in tongue mobility, such as that found with ankyloglossia, may affect the oropharyngeal transit time of the bolus and predispose a person to OPD. This study was conducted to examine the possible relationship between tongue tie and oropharyngeal dysphagia. Data were gathered on 8 participants (5 females, 3 males) between the ages of 12–43 years. The Lingual Frenulum Protocol (Marchesan, 2012) was used to determine tongue tie. An Iowa Oral Performance Instrument (IOPI) measured tongue tip, tongue dorsum, and lip strength, and a combination of electromyography, and the five-finger palpation method measured laryngeal timing. Measurements were compared with normative data from Holzer (2011). Results revealed that participants with ankyloglossia had signs of oral stage dysphagia, including reduced articulator strength (tongue tip and dorsum, and lips) and reduced masseter activity. Oropharyngeal transit times were not significantly different from the norms. Full article