Value of electromyography in differential diagnosis of laryngeal joint injuries after intubation

Risk factors of arytenoid dislocation after endotracheal intubation: A propensity-matched analysis

Objective

Arytenoid dislocation (AD) after general anesthesia with endotracheal intubation (EI) is an iatrogenic injury that impairs patient function and requires reduction. We aimed to investigate the risk factors of AD following EI.

Methods

This retrospective case-control study involved surgical adults who received EI for general anesthesia at a single institution from June 2010 to June 2020. Cases included all the patients who had AD. We used a ratio of 1:5 to identify patients in the propensity-matched control group.

Results

Multivariate analysis of 49 cases with AD and 245 controls without AD demonstrated that the use of a nasogastric (NG) tube (odds ratio [OR], 23.9; 95% confidence interval [CI], 6.8-84.1), undergoing abdominal surgery (OR, 3.7; 95% CI, 1.2-11.9), and an operative time longer than 3 h (OR, 5.2; 95% CI, 2.1-12.9) were risk factors for AD. We did not find significant independent associations between AD and 40 years or older age, gender, body mass index, whether a laryngeal mask airway was used, endotracheal tube size, and EI performers' experience.

Conclusion

The use of an NG tube, abdominal surgery, and longer operative time were risk factors for AD. Among these, the NG tube application showed a strong association with AD. Preventive measures of informing the patients of the increased risk and providing high-level patient monitoring can reduce the incidence of AD.

Level of Evidence

III.

Incidental Diagnosis of Pediatric Arytenoid Cartilage Dislocation During Videofluoroscopic Swallowing Study: A Case Report

Arytenoid cartilage dislocation is one of the most common mechanical causes of vocal fold immobility. The most common etiologies are intubation and external trauma, but its incidence is lower than 0.1%. Its symptoms include dysphonia, vocal fatigue, loss of vocal control, breathiness, odynophagia, dysphagia, dyspnea, and cough. Although there are some reports of arytenoid cartilage dislocation in adults, there are only few reports on its occurrence in children. It is particularly difficult to detect the symptoms of arytenoid cartilage dislocation in uncooperative pediatric patients with brain lesions without verbal output or voluntary expression. We report a case of arytenoid cartilage dislocation with incidental findings in a videofluoroscopic swallowing study performed to evaluate the swallowing function.

Vocal fold paralysis in preterm infants: prevalence and analysis of risk factors

OBJECTIVE

To calculate the prevalence of vocal fold paralysis (VFP) in preterm (<37 weeks of gestation) infants at a single neonatal intensive care unit (NICU) and identify risk factors for the development of VFP.

STUDY DESIGN

This is a case control study of all surviving preterm infants admitted to the NICU at Children's Hospital of Wisconsin from 2006 to 2012, comparing those with and without VFP. Multivariate analysis was performed to identify significant risk factors for VFP.

RESULTS

Of the 2083 patients included, 73 (3.5%) had VFP, including 18% of those at <26 weeks of gestation. On multivariate analyses, VFP was associated with patent ductus arteriosus (PDA) ligation (P<0.001, odds ratio (OR) 15.9, 95% confidence interval (CI) 8.9 to 28.1), history of invasive ventilation (P=0.008, OR 4.5, 95% CI 1.5 to 13.6) and black vs non-black race (P=0.001, OR 2.5, 95% CI 1.5 to 4.3).

CONCLUSION

Given the prevalence of VFP and its associated morbidity, efforts to decrease PDA ligation and invasive ventilation in preterm infants are warranted.

Diagnostic Laryngeal Electromyography: The Wake Forest Experience 1995–1999

BACKGROUND:

Laryngeal electromyography (LEMG) is a valuable diagnostic/prognostic test for patients with suspected laryngeal neuromuscular disorders.

OBJECTIVE:

To report our experience with diagnostic LEMG at the Center for voice Disorders of Wake Forest University and to evaluate the impact of LEMG on clinical management.

METHODS:

Retrospective chart review of 415 patients who underwent diagnostic LEMG over a 5-year period (1995–1999).

RESULTS:

Of 415 studies, 83% (346 of 415) were abnormal, indicating a neuropathic process. LEMG results altered the diagnostic evaluation (eg, the type of radiographic imaging) in 11% (46 of 415) of the patients. Unexpected LEMG findings (eg, contralateral neuropathy) were found in 26% (107 of 415) of the patients, and LEMG results differentiated vocal fold paralysis from fixation in 12% (49 of 415). Finally, LEMG results altered the clinical management (eg, changed the timing and/or type of surgical procedure) in 40% (166 of 415) of the patients.

CONCLUSIONS:

LEMG is a valuable diagnostic test that aids the clinician in the diagnosis and management of laryngeal neuromuscular disorders.

Laryngeal electromyography in dysphonic patients with incomplete glottic closure

The lack of specificity in laryngoscopical examination requires that the diagnosis of superior laryngeal and recurrent laryngeal nerve involvement be carried out with the aid of electromyography.

Objective

This study aims to assess the electrophysiological function of the superior and inferior laryngeal nerves by measuring the electrical activity of the muscles they innervate in dysphonic patients with incomplete closure of the vocal folds during phonation.

Method

Thirty-nine patients with incomplete glottic closure were enrolled in a prospective study and had their cricothyroid, thyroarytenoid, and lateral cricoarytenoid muscles examined bilaterally through electromyography. Insertion activity, electrical activity at rest (fibrillation, positive wave and fasciculation) and during muscle voluntary contraction (recruitment, amplitude, potential length and latency between electrical activity and phonation) were measured.

Results

No altered test results were observed for parameters insertion activity and electrical activity at rest. None of the patients had recruitment dysfunction. The mean electrical potential amplitude values were within normal range for the tested muscles, as were potential durations and latency times between the onset of electrical activity and phonation.

Conclusion

No signs of denervation were seen in the thyroarytenoid, cricothyroid, and lateral cricoarytenoid muscles of the studied patients.

A promising new technique for closed reduction of arytenoid dislocation

Objectives:

To study the effect of a new technique for closed reduction of dislocated arytenoids.

Methods:

The study included 21 females (72.4 per cent) and eight males (27.6 per cent) with a diagnosis of arytenoid dislocation. There were 18 cases of left arytenoid dislocation and 11 of right arytenoid dislocation.Twenty-eight cases had anteromedial dislocation and one had posterolateral dislocation. All patients were treated with closed reduction using custom-made metal rods and an operating microscope, under general anaesthesia.

Results:

Post-operatively, 21 patients’ voices returned completely to normal (including full vocal fold mobility), five had an improved voice and three failed to show any improvement. There were no post-operative complications.

Conclusion:

This new closed reduction technique is a safe procedure for patients with dislocated arytenoids. It is repeatable and the outcome is reliable and effective. Closed reduction can be a useful treatment for arytenoid dislocation.

Arytenoid dislocation: An analysis of the contemporary literature

OBJECTIVES/HYPOTHESIS

To discuss the incidence, diagnosis, laryngeal findings, and management of arytenoid dislocation as a separate entity from vocal fold paralysis.

STUDY DESIGN

Literature review.

METHODS

A contemporary review of the literature was performed by searching the terms arytenoid cartilage dislocation and subluxation in various combinations. Articles were analyzed and selected based on relevance and content.

RESULTS

Arytenoid dislocation is described as an uncommon laryngeal finding associated with intubation or blunt laryngeal trauma. The majority of recent publications are case reports or small case series. Diagnosis of arytenoid dislocation with flexible laryngoscopy, helical computed tomography, videostroboscopy, and laryngeal electromyography is recommended. In most reported cases, diagnosis has been made based on the position of the arytenoid at laryngoscopy. Reduction and repositioning of the arytenoid cartilage is reported with limited success noted with delayed diagnosis. Speech therapy may also be a beneficial treatment option.

CONCLUSIONS

Although arytenoid dislocation is reported in the literature, the body of available evidence fails to sufficiently differentiate it as a separate entity from unilateral vocal fold paralysis. Flexible laryngoscopy is inadequate as a standalone procedure to distinguish arytenoid dislocation from laryngeal nerve injury.

Laryngeal injury from prolonged intubation: a prospective analysis of contributing factors

OBJECTIVES/HYPOTHESIS

The factors leading to laryngeal injury due to intubation are not fully understood. This study sought to determine if duration of intubation, size of endotracheal tube, and/or type of endotracheal tube impact the degree of vocal fold immobility and other laryngeal injury upon extubation.

STUDY DESIGN

Prospective study.

METHODS

Sixty-one adult patients intubated for more than 48 hours were examined by recorded flexible nasolaryngoscopy shortly after extubation.

RESULTS

Forty-one percent of patients had some degree of vocal fold immobility. However, neither the duration of intubation (range, 2-28 days; mean, 9.1 days), the size of endotracheal tube (range, 6 to 8), nor the type of endotracheal tube significantly affected the degree of laryngeal injury including vocal fold immobility. Additionally, none of the collected demographic information (age, gender, height, weight) significantly affected the degree of laryngeal injury.

CONCLUSIONS

In this cohort, duration of intubation, type of endotracheal tube, and size of endotracheal tube do not significantly correlate to the incidence of vocal fold mobility and degree of laryngeal injury noted after prolonged intubation.

Laryngeal Complications of Endotracheal Intubation

An endotracheal tube placed in the larynx, even for a short time, causes at least superficial mucosal damage, an injury that normally heals readily. Long-term intubation, on the other hand, may cause pressure necrosis that can extend into submucosa, perichondrium, and eventually cartilage. The sites of involvement include the medial surface of the arytenoid cartilages, vocal processes, cricoarytenoid joints, posterior glottis, and subglottis. We review the pathogenesis, endoscopic recognition, classification, and progression of intubation injuries and examine the many variables that influence them. Diagrammatic flow charts trace the acute injuries through to their chronic sequelae, including subglottic stenosis, which is commoner in infants and children, and posterior glottic stenosis, which is commoner in adults. Systematic endoscopic assessment, under general anesthesia, using rigid telescopes to evaluate laryngeal damage during intubation is recommended and critically discussed. Endoscopy permits an informed judgment with regard to continuation of intubation. Depending on the severity and depth of ulceration, intubation can be continued (sometimes with a tube of smaller diameter) or tracheotomy performed, with an awareness of the attendant risks and benefits. Unnecessary tracheotomies may be avoided. Further, it may be possible to minimize untoward outcomes of prolonged intubation by using management techniques directed at known risk factors.

Isolated bilateral vocal cord paralysis with intermediate syndrome after organophosphate poisoning

INTRODUCTION

Muscular weakness affecting predominantly the proximal limb muscles and neck flexors is the cardinal feature of intermediate syndrome with cranial nerve palsies occasionally accompanied. Following acute cholinergic phase of organophosphate poisoning (OPP), only a few isolated cases of vocal cord paralysis have been reported in the past. We describe a case of bilateral vocal cord paralysis which occurred in the wake of a clinical recovery from acute cholinergic crisis in OPP.

CASE REPORT

A 32-year-old woman presented with severe cholinergic crisis after ingestion of an unknown amount of dichlorvos in a suicide attempt. The patient was improved from cholinergic crisis by administration of antidotes. On day 4, she complained of progressive dyspnea and dysphonia after removal of the endotracheal tube. Needle electromyography for neuromuscular confirmation was normal. However, laryngeal electromyography (LEMG) findings were consistent with bilateral laryngeal paralysis suggesting the vagus nerve involvement. Her vocal cord movements were restored to near normal with time and she was discharged on the 20th day after admission.

CONCLUSIONS

Physicians should account for the neurotoxic effects of organophosphate poisoning during the first line management of exposed patients. Isolated bilateral vocal cord paralysis (BVCP) should be excluded as a cause, if dysphonia or respiratory distress occurs after extubation in patients with intermediate syndrome. LEMG in such cases can be an important diagnostic adjunct.

The role of laryngeal electromyography in the diagnosis of vocal fold immobility in children

INTRODUCTION

Pathology may affect the muscles that control vocal function directly by affecting peripheral function or indirectly by affecting the central nervous system. Clinically, muscle function can be assessed by observing the movements of the structures themselves or by recording the electrical activity of the muscles (electromyography, EMG). Since EMG is an invasive technique, it has enjoyed limited use in the diagnosis and management of voice disorders, especially in children. Laryngeal EMG may be helpful in those patients with voice problems of suspected neurological or neuromuscular etiology.

OBJECTIVE

The purpose of this paper is to study the role of laryngeal EMG in the clinical evaluation of unilateral vocal fold immobility in children.

MATERIALS AND METHODS

Twenty-five children with unilateral vocal fold paralysis were studied. Twenty-five patients with vocal pathologies secondary to vocal abuse and misuse were studied as controls. The sensitivity and specificity of the EMG as a diagnostic marker for vocal fold paralysis were obtained. Additionally, nine patients with traumatic arytenoid dislocation were also studied. All patients were subjected to laryngeal EMG. EMG showed a sensitivity of 100%, and specificity of 92%. Only two patients, present with a functional voice disorder, showed abnormalities in the EMG recordings. In the nine patients with arytenoid dislocation, EMG showed normal parameters.

CONCLUSION

EMG seems a safe and reliable test for evaluating patients with vocal fold immobility. Moreover, the EMG recordings were helpful in differentiating vocal fold paralysis from arytenoid dislocation. EMG can provide useful data concerning muscle denervation, and more importantly, reinnervation. Besides its utility for the diagnosis, serial EMG can be useful for monitoring recovery and for establishing a reliable prognosis, and hence, an adequate treatment plan.

Aggravation of laryngeal rheumatoid arthritis after use of a laryngeal mask airway

We report a case of aggravation of laryngeal rheumatoid arthritis (RA) after the use of a laryngeal mask airway (LMA). The patient was a 55-year-old woman with severe RA who underwent wrist arthrodesis under general anesthesia using a size 3 LMA. A few days after the operation, she reported hoarseness. Inflammation of the arytenoid region and vocal cord immobility were observed by fiberoptic nasolaryngoscopy. Vocal function returned to normal by postoperative day 42 in response to prednisolone therapy. In this case, stridor was misdiagnosed preoperatively, and postoperative symptoms and local findings were probably caused by aggravation of laryngeal RA resulting from substantial compression of the arytenoid region by the LMA. For patients with RA referred for surgery, a careful search for cricoarytenoid arthritis is essential, particularly in those with laryngeal stridor, because it may be aggravated after general anesthesia.

Arytenoid cartilage dislocation: a 20-year experience

SUMMARY

Arytenoid cartilage dislocation is an infrequently diagnosed cause of vocal fold immobility. Seventy-four cases have been reported in the literature to date. Intubation is the most common origin, followed by external laryngeal trauma. Decreased volume and breathiness are the most common presenting symptoms. We report on 63 patients with arytenoid cartilage dislocation treated by the senior author (RTS) since 1983. Significantly more posterior than anterior dislocations were represented. Although reestablishing joint mobility is difficult, endoscopic reduction should be considered to align the heights of the vocal processes. This process may result in significant voice improvement even long after the dislocation. Strobovideolaryngoscopy, laryngeal electromyography, and laryngeal computed tomography (CT) imaging are helpful in the evaluation of patients with vocal fold immobility to help distinguish arytenoid cartilage dislocation from vocal fold paralysis. Familiarity with signs and symptoms of arytenoid cartilage dislocation and current treatment techniques improves the chances for optimal therapeutic results.

Blunt laryngeal trauma resulting in arytenoid dislocation and dysphonia

We present a case of left arytenoid dislocation due to blunt laryngeal trauma causing a subsequent large granuloma formation resulting in dysphonia and stridor. The patient underwent emergency excision of the obstructive granuloma and speech therapy was started post-operatively. A few weeks after surgery, the granuloma started to recur and laryngeal manipulation by a specialist osteopath was performed. A few weeks after the conservative management, the recurred granuloma resolved completely and patient's voice improved remarkably. Dislocation of the arytenoid cartilage due to blunt trauma is relatively rare and a consequent spontaneous granuloma formation has not been reported so far in the literature. This is also the first report about efficacy of speech therapy combined with laryngeal manipulation in the management of the arytenoid dislocation and the subsequent laryngeal granuloma.

Electromyography and the immobile vocal fold

Laryngeal EMG has become a useful tool for the otolaryngologist in the four decades since the pioneering work of Faaborg-Anderson and Buchtal. It is able to distinguish between mechanical limitation and denervation in an immobile vocal fold. In the paralyzed vocal fold, it can guide workup by pointing to the site of the lesion. In the hands of a circumspect clinician, it can provide clinically valuable information regarding prognosis. Useful application of laryngeal EMG must rest on the basic fact that it isa qualitative test. Because of factors like sampling error, interfering signal from neighboring muscles, difficulties in needle placement, and our in-complete understanding of reinnervation physiology, the boundary between sophisticated, subtle interpretation and overreading is particularly difficult to distinguish. EMG diagnosis is based on patterns of abnormalities over time and, like other tests, requires interpretation in a clinical context. As in any such undertaking, there is no substitute for good judgment and experience. The most important benefit of clinical use of laryngeal EMG may be that it has catalyzed and broadened interest in laryngeal neurophysiology in the same way that stroboscopy has focused attention on the structure and function of the vocal fold lamina propria. The continuing refinement of electrodiagnostic approaches to the larynx that has resulted, including quantitative, single-fiber. and vector laryngeal EMG, and evolving methods of nerve conduction testing will continue to yield important insights into mechanisms of neural control that are likely to drive developments in the treatment of vocal fold paralysis in the future.

[Lesions to lips, oral and nasal cavities, pharynx, larynx, trachea and esophagus due to endotracheal intubation and its alternatives]

Dysphagia of greater than 48 h duration is an indication for indirect laryngoscopy and when odynophagia and otalgia occur simultaneously, the possibility of subluxation of the arytenoids demands an urgent ENT assessment. The potential seriousness of laryngeal lesions following intubation obliges us to use the smallest compatible endotracheal tube. The occurrence of pain cervical surgical emphysema and fever suggests a pharyngeal lesion necessitating the suspension of oral feeding and the initiation of antibiotic therapy with anaerobic activity, while awaiting possible surgical intervention. There is no argument to use a tooth-guard for each intubation, but tooth fragility must be researched. The incidence of nasal fossa trauma is reduced with the use of nasal packs impregnated with local anaesthetic containing a vasoconstrictor. This allows the introduction of a small flexible lubricated tube. Laryngeal mask-induced sore throat is more common than the more serious injuries. The classical technique of introducing a laryngeal mask of appropriate size (4 for women, 5 for men) in which the cuff is inflated to a leak pressure of 20 cm H(2)O reduces this frequency. The facial mask may cause injuries especially with prolonged use. The incidence of pulmonary aspiration, linked to the action of drugs, raised intra-abdominal pressure; an emergent situation or difficult intubation is decreased with the performance of the Sellick maneuver at intubation, rapid induction and the neutralization of gastric acidity. A meticulous technique of insertion of the, individualized anaesthesia, particular vigilance at the time of decurarisation and position changes and a calm awakening assure its optimal use, unless the Proseal laryngeal mask modifies this point of view.

Lack of evoked laryngeal electromyography response in patients with a clinical diagnosis of vocal cord paralysis

There has been recent debate about whether patients with vocal cord immobility have a neurologic paralysis or whether synkinesis, the misdirection of axons to competing laryngeal muscles, is responsible for the lack of voluntary vocal cord motion. This issue was studied in 15 patients with vocal cord paralysis who underwent laryngeal reinnervation. Evoked electromyography was performed with a surface electrode endotracheal tube. The recurrent laryngeal nerve (RLN) was identified and stimulated with constant current. Of the 15 patients, only 1 produced a compound muscle action potential upon nerve stimulation. The remaining 14 patients had no evoked response during RLN stimulation. A control group of 8 patients with normal vocal cord mobility was studied, and each had a normal evoked electromyography response after RLN stimulation. These results support the assertion that patients who require treatment for vocal cord paralysis do not have synkinesis produced by RLN reinnervation.

Postintubation interarytenoid adhesion

Interarytenoid fibrous adhesion is a poorly recognized complication of intubation and is frequently confused with bilateral vocal cord paralysis. Early diagnosis and treatment is essential for optimal management. Otolaryngologists should constantly remain alert for interarytenoid fibrous scar to establish the diagnosis as early as possible, optimizing the probability of restoring normal breathing and quality of life and avoiding an unnecessary tracheotomy. Surgical laser reduction is appropriate in all cases when other miscellaneous laryngeal injury lesions are eliminated. Direct laryngoscopy with careful examination of the posterior commissure and laryngeal electromyography are the 2 main clinical diagnostic aids contributing to establish the diagnosis.

Laryngeal electromyography: diagnostic and prognostic applications

Laryngeal electromyography is a crucial diagnostic test in laryngology. Laryngeal electromyography is important for the diagnosis of vocal fold paresis and cricoarytenoid joint pathology (e.g., arytenoid dislocation). In addition, laryngeal electromyography offers prognostic information regarding potential vocal fold paralysis recovery, which can improve the management strategies for vocal fold paralysis.

Botulinum toxin: adjunctive treatment for posterior glottic synechiae

INTRODUCTION

Synechiae formation of the posterior glottis can result in tracheostomy dependence secondary to airway obstruction. Stenosis is caused by total or partial fixation of the vocal folds in adduction resulting from scar contracture. The treatment poses a management dilemma because of recurrent scar formation, made worse by mobility of the vocal folds. Although various treatment options from conservative endoscopic repair to open procedures have been proposed, the results are not satisfactory and patients often require multiple procedures.

METHODS

We present the trial of a conservative approach that includes microscopic CO2 laser resection of the scar with concomitant botulinum toxin injection of the interarytenoid and thyroarytenoid muscles of the more mobile cord. This results in a temporary paresis of the adductor muscles and hence prevents overadduction in the posterior commissure during the postoperative healing period.

STUDY DESIGN

We present the surgical technique and results in three patients who underwent the procedure.

RESULTS

Treatment in all three patients was successful.

CONCLUSIONS

The appropriate use of botulinum toxin may help improve the treatment outcome of posterior synechiae of the larynx without sacrificing any laryngeal components.