Vocal cord paralysis: anatomy, imaging and pathology

Correlation of acoustic voice analysis and Voice Handicap Index in patients with postoperative unilateral vocal cord paralysis after thyroid surgery

Unilateral vocal cord paralysis is frequently observed in patients who undergo thyroid surgery. This study explored the correlation between acoustic voice analysis (objective measure) and Voice Handicap Index (VHI, a self-assessment tool). One hundred and forty patients who had thyroid surgery with or without postoperative unilateral vocal cord paralysis (PVCP and NPVCP) were included. The patients were evaluated by the VHI and Dysphonia Severity Index (DSI) tools. VHI scores were significantly higher in PVCP patients than in NPVCP patients. Jitter (%) and shimmer (%) were significantly increased, whereas DSI was significantly decreased in PVCP patients. Receiver operating characteristics curve revealed that VHI scores were associated with the diagnosis of PVCP, of which VHI total score yielded an area under the curve (AUC) of 0.81. Among acoustic parameters, DSI was highly associated to PVCP (AUC=0.82, 95%CI=0.75 to 0.89). Moreover, we found a correlation between VHI scores and voice acoustic parameters. Among them, DSI had a moderate correlation with functional and VHI scores, as suggested by an R value of 0.41 and 0.49, respectively. VHI scores and acoustic parameters were associated with the diagnosis of PVCP.

Quantification of vessel separation using the carotid-jugular angle to predict the nerve origin of neck peripheral nerve sheath tumours: a pooled analysis of cases from the literature and a single-center cohort

BACKGROUND

Postoperative nerve palsy is a major complication following resection of neck peripheral nerve sheath tumours (PNSTs). Accurate preoperative identification of the nerve origin (NO) can improve surgical outcomes and patient counselling.

MATERIAL AND METHODS

This study was a retrospective cohort and quantitative analysis of the literature. The authors introduced a parameter, the carotid-jugular angle (CJA), to differentiate the NO. A literature review of neck PNST cases from 2010 to 2022 was conducted. The CJA was measured from eligible imaging data, and quantitative analysis was performed to evaluate the ability of the CJA to predict the NO. External validation was performed using a single-centre cohort from 2008 to 2021.

RESULTS

In total, 17 patients from our single-centre cohort and 88 patients from the literature were analyzed. Among them, 53, 45, and 7 patients had sympathetic, vagus, and cervical nerve PNSTs, respectively. Vagus nerve tumours had the largest CJA, followed by sympathetic tumours, whereas cervical nerve tumours had the smallest CJA ( P <0.001). Multivariate logistic regression identified a larger CJA as a predictor of vagus NO ( P <0.001), and receiver operating characteristic (ROC) analysis showed an area under the curve (AUC) of 0.907 (0.831-0.951) for the CJA to predict vagus NO ( P <0.001). External validation showed an AUC of 0.928 (0.727-0.988) ( P <0.001). Compared with the AUC of the previously proposed qualitative method (AUC=0.764, 0.673-0.839), that of the CJA was greater ( P =0.011). The cut-off value identified to predict vagus NO was greater than or equal to 100°. Receiver operating characteristic analysis showed an AUC of 0.909 (0.837-0.956) for the CJA to predict cervical NO ( P <0.001), with a cut-off value less than 38.5°.

CONCLUSIONS

A CJA greater than or equal to 100° predicted a vagus NO and a CJA less than 100° predicted a non-vagus NO. Moreover, a CJA less than 38.5 was associated with an increased likelihood of cervical NO.

Vocal cord paralysis associated with pleuroparenchymal fibroelastosis: A case report and literature review

Here, we report a case of idiopathic pleuroparenchymal fibroelastosis (PPFE) that progressed to pulmonary aspergilloma, aspiration pneumonia, and left vocal cord paralysis (VCP). To date, five cases of PPFE with VCP have been reported, including the present case. Aspiration pneumonia occurred in three cases, leading to death in two cases. Four cases had left-sided paralysis, in two of which, the paralysis occurred on side opposite to the predominant side (right side) of PPFE. Structural mechanisms underlying the recurrent laryngeal nerve could be involved. This report may further highlight the existence of hoarseness and dysphagia in PPFE.

Hypertrophic olivary degeneration associated with bilateral vocal cord adductor dystonia

BACKGROUND

Hypertrophic olivary degeneration (HOD) is a rare condition caused by lesions within the dentato-rubro-olivary pathway, resulting in ocular nystagmus and palatal myoclonus (oculopalatal tremor) but not usually dystonia. Dystonia is an uncommon association, and we present the first reported association of hypertrophic olivary degeneration with bilateral vocal cord dystonia.

CASE PRESENTATION

A 33 year old male presented initially with acute hydrocephalus on the background of previous ventriculoperitoneal (VP) shunting for previously treated medulloblastoma. After revision of the VP shunt, the patient developed progressive hiccups and stridor leading to respiratory failure requiring intubation. Ocular pendular nystagmus and palatal myoclonus at 3 Hz was observed. Flexible nasendoscopy (FNE) demonstrated bilateral tonic adduction of the vocal folds with 3 Hz coarse supraglottic, pharyngeal and palatal rhythmic myoclonus. MRI imaging demonstrated T2 hyperintensity within the bilateral inferior olivary nuclei consistent with stage 3 radiological HOD.

CONCLUSIONS

Dystonia is a rarely reported phenomenon in HOD but is not unexpected with the inferior olivary nucleus implicated in dystonic disorders. We report the association of HOD with bilateral vocal cord adductor dystonia, a potentially life threatening condition.

Dysphagia with Unilateral Vocal Cord Paralysis in Herpes Zoster: A Case Report

Herpes zoster is caused by the varicella-zoster virus, which becomes latent in ganglia after primary infection. When the varicella-zoster virus reactivates on the cranial nerve, the patient can suffer from cranial nerve palsy, pain, and skin lesions on the head and neck area. A 57-year-old immunocompetent male presented with dysphagia lasting 10 days. Computed tomography and other neurological findings were normal. However, laryngoscopy showed right vocal cord paralysis, which might be the reason for dysphagia in this patient. There was a grouped crusted lesion on the right posterior auricular area that appeared 5 days after the dysphagia. After famciclovir and prednisolone combination therapy, the patient was cured with no sequelae. This is a rare case of herpes zoster in an immunocompetent patient who presented with dysphagia. In addition, it was difficult to make an accurate diagnosis because his skin lesion appeared several days after dysphagia.

A Study on Voice Measures in Patients With Alzheimer's Disease

OBJECTIVE

As Alzheimer's disease (AD) might provoke certain nerve disorders, patients with AD can acquire sensorimotor adaptation problems, and thus the acoustic characteristics of the speech they produce may differ from those of healthy subjects. This study aimed to (1) extract acoustic characteristics (relating to articulatory gestures) potentially useful for detecting AD and (2) examine whether these characteristics could help identify AD patients.

METHODS

A total of 50 individuals participated in the study, including the AD group (17 cases), the Neurologically Healthy (NH) group (13 cases), the Mild Cognitive Impairment (MCI) group (11 cases), and the Vascular Cognitive Impairment (VCI) group (9 cases). Voice samples involving three vowels (/i/, /a/, and /u/) and six consonants (/p/, /pʰ/, /t/, /tʰ/, /k/, and /kʰ/) were collected using a digital recorder (TASCAM DR40X). Microphone-to-mouth distance was maintained at 30 cm. Acoustic measures included F0, jitter, shimmer, HNR, F1, F2, F3, and VOT.

RESULTS

One-way ANOVA tests were carried out to compare the acoustic measures among the four groups. F3 of vowel /u/, F2 bandwidth of vowel /a/, VOT of consonant /t/, and male participants' F0 of three vowels (/a/, /i/, and /u/) were found significantly different, while no significant differences were found in the other measures.

CONCLUSION

Some acoustic characteristics can indeed help detect AD patients.

Diferencias en el comportamiento glótico y supraglótico y en la estructura de los pliegues vocales entre mujeres con odinofonía y asintomáticas

El estudio de la odinofonía ha sido escasamente abordado por las disciplinas vinculadas a la terapéutica vocal. La comprensión de aspectos esenciales para su terapéutica, como el comportamiento glótico y supraglótico, aún es emergente. El objetivo de este trabajo fue comparar el comportamiento glótico y supraglótico y la estructura de los pliegues vocales entre mujeres con odinofonía yasintomáticas. Se trabajó con 50 mujeres con voces profesionales, cuya edad promedio fue de 25,78 ± 3,50 años. Se formaron dos grupos, G1 (asintomáticas) y G2 (con odinofonía). Se utilizó un videolaringoscopio con luz continua para examinar la conducta supraglótica y la estructura cordal, y un electroglotógrafo para analizar el comportamiento de los pliegues vocales. En el comportamiento supraglótico, el 64 % de las participantes de G2 exhibió mayor compresión supraglótica en comparación a G1. El acortamiento anteroposterior en conjunto a la compresión medial fue la configuración más frecuente en G2, mientras que el acortamiento anteroposterior en solitario, correspondió a la configuración supraglótica más frecuente en G1. En el 60 y 84 % de las participantes de G2 se observó prominencia del proceso vocal y ventrículo espacioso junto a un pliegue vocal adelgazado, respectivamente. En la electroglotografía se evidenció que en G1 el cociente de contacto fue de 0,50 ± 0,34 y en G2, de 0,41 ± 0,31 (p < 0,05). En conclusión, en las mujeres que sufren de odinofonía se observaron signos de atrofia cordal, mientras que en oscilación se evidenciaron compresiones supraglóticas compensatorias y anomalías vinculadas a la aproximación o aducción cordal.

LARNet-STC: Spatio-temporal orthogonal region selection network for laryngeal closure detection in endoscopy videos

The vocal folds (VFs) are a pair of muscles in the larynx that play a critical role in breathing, swallowing, and speaking. VF function can be adversely affected by various medical conditions including head or neck injuries, stroke, tumor, and neurological disorders. In this paper, we propose a deep learning system for automated detection of laryngeal adductor reflex (LAR) events in laryngeal endoscopy videos to enable objective, quantitative analysis of VF function. The proposed deep learning system incorporates our novel orthogonal region selection network and temporal context. This network learns to directly map its input to a VF open/close state without first segmenting or tracking the VF region. This one-step approach drastically reduces manual annotation needs from labor-intensive segmentation masks or VF motion tracks to frame-level class labels. The proposed spatio-temporal network with an orthogonal region selection subnetwork allows integration of local image features, global image features, and VF state information in time for robust LAR event detection. The proposed network is evaluated against several network variations that incorporate temporal context and is shown to lead to better performance. The experimental results show promising performance for automated, objective, and quantitative analysis of LAR events from laryngeal endoscopy videos with over 90% and 99% F1 scores for LAR and non-LAR frames respectively.

Pediatric Vocal Fold Paresis and Paralysis: A Narrative Review

Importance

Vocal fold paralysis (VFP) results from the disruption of neural motor outputs to laryngeal muscles. Children with VFP manifest various degrees of difficulties in phonation, breathing, and swallowing. Although the etiologic characteristics and symptoms of VFP are well established in adults, corresponding clinical profiles are notably different in children. Clinical management of VFP is particularly challenging in children because their larynges are still actively developing and the recovery of disrupted laryngeal nerves is often unpredictable. This review discusses the neurologic conditions and diagnostic and treatment considerations in pediatric VFP.

Observations

Injury to the peripheral laryngeal nerves and certain central nervous system diseases, such as Arnold-Chiari malformation type II, can result in VFP in infants and children. The incidence of unilateral vs bilateral VFP is variable across pediatric studies. Most reported VFP cases are associated with injury of the recurrent laryngeal nerve. Laryngeal electromyography requires needle insertion that must be performed under anesthesia with special care in the pediatric setting. Neither normative values nor standardized procedures of laryngeal electromyography are currently established for the pediatric population. Laryngeal reinnervation, endoscopic arytenoid abduction lateropexy, and laryngeal pacing are plausible treatment options for pediatric VFP. Despite these new advances in the field, no corresponding efficacy data are available for clinicians to discern which type of patients would be the best candidates for these procedures.

Conclusions and Relevance

The neuroanatomy and neurophysiology of VFP remain more elusive for the pediatric population than for adults. Basic and clinical research is warranted to fully comprehend the complexity of this laryngeal movement disorder and to better inform and standardize clinical practice.

Third branchial cleft cyst as a cause of hoarseness: a case report

Third branchial cleft cyst is a rare congenital disease of the neck. It presents as a painless mass that develops rapidly in the neck following an infection. This is the first case report of recurrent laryngeal nerve palsy caused by a third branchial cleft cyst. A 30-year-old woman presented with a 3-month history of hoarseness as her only symptom; she had no pain, fever, dysphagia, dyspnoea, or palpable neck mass. Laryngoscopy revealed that her right vocal cord was paralyzed. Computed tomography and magnetic resonance imaging revealed a cystic mass in the right tracheoesophageal groove that was closely associated with the trachea. Intraoperatively, the cyst was found not to originate from the thyroid or trachea, but it was compressing the right recurrent laryngeal nerve. The hoarseness resolved the day after the cyst was removed.

The role of imaging in the evaluation of hoarseness: A review

Hoarseness is a common symptom indicating an abnormal change in the quality of voice and has a lifetime prevalence of around 30%. There are multiple causes of hoarseness, ranging from acute laryngitis, chronic laryngitis, laryngopharyngeal reflux, functional dysphonia due to vocal overuse or abuse, vocal cord paralysis (VCP), to various pathologies and masses in the larynx. A detailed history and thorough physical examination, and in many cases, laryngoscopy by a clinician are the initial steps in its management. Laryngoscopy should be considered if hoarseness persists for more than 2 weeks without a known benign cause. An Ear Nose and Throat surgeon performs direct visualization by laryngoscopy to rule out VCP or a lesion in the larynx, and it should be performed before ordering any imaging. CT with contrast is the imaging of choice to evaluate the laryngeal tumors and find the etiology of VCP. Typical findings of VCP are ipsilateral dilatation of the pyriform sinus and laryngeal ventricle, thickening and medialization of the ipsilateral aryepiglottic fold, medialization of the arytenoid cartilage and posterior aspect of the true vocal cord (TVC) atrophy of the TVC, and loss of the subglottic arch. The lesions causing the VCP may extend from the medulla, jugular foramen, carotid space, and upper mediastinum. CT neck must cover the aorticopulmonary window when evaluating the left VCP to cover the left recurrent laryngeal nerve's origin.

PET/CT Variants and Pitfalls in Head and Neck Cancers Including Thyroid Cancer

PET/CT imaging is a dual-modality diagnostic technology that merges metabolic and structural imaging. There are several currently available radiotracers, but ¹⁸F-FDG is the most commonly utilized due to its widespread availability. ¹⁸F-FDG PET/CT is a cornerstone of head and neck squamous cell carcinoma imaging. ⁶⁸Ga-DOTA-TOC is another widely used radiotracer. It allows for whole-body imaging of cellular somatostatin receptors, commonly expressed by neuroendocrine tumors and is the standard of reference for the characterization and staging of neuroendocrine tumors. The normal biodistribution of these PET radiotracers as well as the technical aspects of image acquisition and inadequate patient preparation affect the quality of PET/CT imaging. In addition, normal variants, artifacts and incidental findings may impede accurate image interpretation and can potentially lead to misdiagnosis. In order to correctly interpret PET/CT imaging, it is necessary to have a comprehensive knowledge of the normal anatomy of the head and neck and to be cognizant of potential imaging pitfalls. The interpreter must be familiar with benign conditions which may accumulate radiotracer potentially mimicking neoplastic processes and also be aware of malignancies which can demonstrate low radiotracer uptake. Appropriate use of structural imaging with either CT, MR or ultrasound can serve a complimentary role in several head and neck pathologies including local tumor staging, detection of bone marrow involvement or perineural spread, and classification of thyroid nodules. It is important to be aware of the role of these complementary modalities to maximize diagnostic accuracy and patient outcomes. The purpose of this article is to outline the basic principles of PET/CT imaging, with a focus on ¹⁸F-FDG PET/CT and ⁶⁸Ga-DOTA PET/CT. Basic physiology, variant imaging appearances and potential pitfalls of image interpretation are presented within the context of common use cases of PET technology in patients with head and neck cancers and other pathologies, benign and malignant.

Bilateral vocal fold paralysis after COVID-19 infection. Another neuro-invasive manifestation? Case series

The agent that causes the coronavirus disease (COVID-19), associated with the severe acute respiratory syndrome (SARS-CoV-2), produces a spectrum of symptoms that mainly affect the respiratory system, the central nervous system (CNS), the regulation of hemostasis and the immune system. Bilateral vocal fold paralysis (BVFP) is a condition of unknown incidence among infected patients, either because it is short-lived or because of the difficulty in establishing a direct cause to the virus. Viral infection has been described in the literature as a cause of BVFP and there is the suspicion that a proportion of the idiopathic cases are due to undiagnosed viral infections. Although the neurotropic mechanisms for SARS-CoV-2 remain unclear, there is strong evidence to ensure its neuroinvasive potential. The most frequent etiologies of BVFP are trauma, neoplasm, and neurological, but a viral origin should not be ruled out. Causality between COVID-19 and BVFP is plausible and will require further study in the short and long term.

Vocal Fold Motion Impairment Following Chemotherapy Administration: Case Reports and Review of the Literature

OBJECTIVE

Chemotherapy-induced vocal fold motion impairment (CIVFMI) is a rare complication of cancer therapy with potential for airway compromise. The objective of this review is to present 2 new cases of CIVFMI to add to the literature as well as characterize the demographics, symptoms, exam findings, airway complication rates and prognosis of CIVFMI.

METHODS

A search of Pubmed/MEDLINE (1970 to May 1, 2020), Embase (1970 to May 1, 2020), and Cochrane Library using medical study heading (MeSH) terms related to chemotherapy (drug therapy, chemotherapy, vincristine, vinblastine, paclitaxel) and vocal cord motion impairment (vocal cord, cords, vocal folds, immobility, hypomobility) was performed. Exploratory pooling of data without formal meta-analysis was performed.

RESULTS

A preliminary search yielded 148 abstracts, review articles and studies. A total of 23 studies met inclusion criteria. There were 35 total cases presented in the literature, with a mean age of 29.5 (0.4-78). The most common cancer diagnosis was acute lymphoblastic leukemia (n = 15, 42.9%), and the most common agent was vincristine (n = 30, 85.7%). Dysphagia, bilateral CIVFMI, and vocal fold immobility rather than hypomobility were more common in pediatric patients. There were 8 cases of surgical airway intervention, including tracheostomy and posterior cordotomy. The duration of symptoms was 7 to 420 days, and spontaneous resolution was reported in 32 cases.

CONCLUSIONS

CIVFMI has potential for airway complications requiring surgical intervention. Spontaneous resolution after cessation of the offending agent is the most likely outcome. Bilateral CIVFMI, dysphagia and vocal fold immobility are more common in the pediatric population.

Anatomical Variations of the Recurrent Laryngeal Nerve and Implications for Injury Prevention during Surgical Procedures of the Neck

Accurate knowledge of anatomical variations of the recurrent laryngeal nerve (RLN) provides information to prevent inadvertent intraoperative injury and ultimately guide best clinical and surgical practices. The present study aims to assess the potential anatomical variability of RLN pertaining to its course, branching pattern, and relationship to the inferior thyroid artery, which makes it vulnerable during surgical procedures of the neck. Fifty-five formalin-fixed cadavers were carefully dissected and examined, with the course of the RLN carefully evaluated and documented bilaterally. Our findings indicate that extra-laryngeal branches coming off the RLN on both the right and left side innervate the esophagus, trachea, and mainly intrinsic laryngeal muscles. On the right side, 89.1% of the cadavers demonstrated 2–5 extra-laryngeal branches. On the left, 74.6% of the cadavers demonstrated 2–3 extra-laryngeal branches. In relation to the inferior thyroid artery (ITA), 67.9% of right RLNs were located anteriorly, while 32.1% were located posteriorly. On the other hand, 32.1% of left RLNs were anterior to the ITA, while 67.9% were related posteriorly. On both sides, 3–5% of RLN crossed in between the branches of the ITA. Anatomical consideration of the variations in the course, branching pattern, and relationship of the RLNs is essential to minimize complications associated with surgical procedures of the neck, especially thyroidectomy and anterior cervical discectomy and fusion (ACDF) surgery. The information gained in this study emphasizes the need to preferentially utilize left-sided approaches for ACDF surgery whenever possible.

Cardiovocal Syndrome Secondary to Thoracic Aortic Aneurysm: An Old Sign Revisited

A 56-year-old male, chronic smoker, presented with persistent dry cough, hoarseness of voice and difficulty in swallowing. Indirect laryngoscopy revealed left vocal cord paralysis. Further evaluation revealed eccentric saccular aneurysms arising from the aortic arch and descending thoracic aorta, compressing the trachea, esophagus, left atrium and left recurrent laryngeal nerve. The patient was diagnosed with Ortner's syndrome which is an uncommon presentation of aortic aneurysm. He awaits an endovascular aorta aneurysm repair.

Efficacy of speech language therapy intervention in unilateral vocal fold paralysis - a systematic review and a meta-analysis of visual-perceptual outcome measures

OBJECTIVE

Unilateral vocal folds paralysis is a disorder that affects a patient's quality-of-life by disturbing their phonation, breathing, and swallowing activities. This systematic review aimed to estimate the efficacy of voice treatment on the vocal fold motility in adult patients with unilateral vocal folds paralysis.

METHODS

PubMed, CINAHL, CENTRAL, and Web of Science were searched for retrospective and prospective cohort, case-control, and cross-sectional with comparative studies with adults that were published between 1 January 2008 to 31 December 2018. After applying the inclusion and exclusion criteria a total of 10 studies containing morpho-functional evaluation results were included in the analysis. Pooled data analysis of the motility of the vocal folds before and after voice therapy allowed inferring about the efficacy of voice therapy intervention in patients with unilateral vocal folds paralysis. A random-effect model was used to estimate the effect size. Publication bias was considered.

RESULTS

The pooled data analysis of the visual-perceptual measures revealed that vocal fold motility improved in 72% (95% CI: 64.0-80.0) of all patients after the therapeutic interventions. The inconsistency index (I² = 18.35%) of the studies included in this meta-analysis revealed an extremely low heterogeneity. Funnel plot and Cochran's Q test showed no publication bias. The systematic review was limited to only English language articles.

CONCLUSION

This meta-analysis supports the evidence that voice therapy intervention can have a positive effect on the vocal fold motility, that is, they can improve the glottal gap closure, irrespective of the exercises and techniques used.

Setup and initial testing of an endoscope manipulator system for assistance in transoral endoscopic surgery

Purpose For the treatment of malignant diseases of the oral cavity and the larynx, a total or partial resection is the standard therapy, while in special cases chemo- and/or external radiation therapy is considered. Transoral access reduces trauma and hospitalization time. Transoral surgery is usually executed using external microscopic imaging. Therefore, the microscope is placed in the visual line of the opening of the mouth and throat. However, specific anatomical structures like the posterior commissure (dorsal end of the vocal cords) are not visible in these procedures. An endoscopic approach can improve this problem. We introduce a new prototype system for endoscopic assisted transoral surgery. Methods Based on clinical observation and discussions with professional users and surgeons, the clinical need was identified and specified. A general concept or an endoscopic manipulator to assist microlaryngeal surgery was designed. For that a steerable rigid endoscope was combined with an actuator that allows translational and rotational movement. A quick release fastener was designed allowing for fast change of the endoscope and independence from its shape and type. The actuator was fixed on a commercially available, semi-active medical holding arm for easy positioning. The holder can be fixed to the standard rails of the surgical table. The piezoelectric drives integrated in the actuator are activated with a foot pedal. This allows easy and fast fine positioning, while the hands are free to perform the surgery with standard instruments for microlaryngeal surgery. Results A prototype of the system for endoscopic assisted transoral surgery was developed. The entire technical setup was tested in terms of usability and performance in a simulated surgical scenario. A basic phantom, representing the throat and vocal cords was created and placed on a surgical table. The system was installed on the table and the clinical workflow of a simulated endoscopic assisted surgery on the vocal cords was performed. The performance of the setup and the procedure success was evaluated by clinical users. Conclusion Fixture of the system on the surgical table is fast and easy due to its low weight and compact design. The medical holder allows a fast initial positioning of the system in front of the phantom patient. An easy insertion and removal of the endoscope was realized using the quick release fastener. The developed endoscope fixation is universally adaptable and not limited to a single type of endoscope. The piezoelectric drives, combined with the foot pedal, allow a precise placement and readjustment of the endoscope during surgery. The use of a multi view endoscope enables a variable view on the surgical situs. The size and shape of the whole setup offer excellent access to the targeted structures. The development was classified beneficial by the clinical users.

Peripheral component of laryngeal and pharyngeal motor evoked potentials

In this study, the responses of thyroarytenoid (TA) and cricopharyngeus (CP) muscles were simultaneously recorded to peripheral magnetic stimulation of the vagus nerve. Recordings were performed in 13 subjects by means of concentric needle EMG electrodes inserted in the TA and CP. Magnetic shocks were delivered to the vagus nerve with a round coil placed occipitally, while EMG was silent in the TA. In all subjects, clear-cut responses were obtained simultaneously in both muscles. In TA compared to CP, the maximum amplitude of the responses were higher, whereas the onset latency was shorter. Our results revealed that simultaneous recordings of TA and CP motor responses to occipital magnetic stimulation enabled a reliable evaluation of their peripheral innervation by the vagus nerve.

Causes and imaging manifestations of paralysis of the recurrent laryngeal nerve

The vocal cords play a key role in the functions of the larynx. Their motor innervation depends on the recurrent laryngeal nerve (a branch of the tenth cranial nerve), which follows a long trajectory comprising intracranial, cervical, and mediastinal segments. Vocal cord paralysis usually manifests as dysphonia, the main symptom calling for CT study, the first-line imaging test to investigate the cause of the lesion. Patients are asymptomatic in a third of cases, so the incidental detection of signs of vocal cord paralysis in a CT study done for other reasons should prompt a search for a potentially severe occult lesion. This article aims to familiarize readers with the anatomy of the motor innervation of the glottis, the radiological presentation and most common causes of vocal cord paralysis, and conditions that can simulate vocal cord paralysis.

A Rare Case of C2 Sensory Blockade with Preserved Phrenic Nerve Function in an Obstetric Patient

High neuraxial blockade is a serious complication in obstetric patients and requires prompt recognition and management in order to optimize patient outcomes. In cases of high neuroblockade, patients may present with significant hypotension, dyspnea, agitation, difficulty speaking or inability to speak, or even loss of consciousness. We report the unusual presentation of an obstetric patient that remained hemodynamically stable and had the preserved ability to initiate breaths despite sensory blockade up to C2. The presence of differential motor and sensory block documented in this case helped enable the patient to be managed with noninvasive ventilatory support until the high blockade regressed and we are not aware of any other similar reports in literature.