You are in: eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > LARYNGOLOGY Vocal Fold Paralysis, BilateralArticle Last Updated: Sep 9, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Joel A Ernster, MD, Active Staff, Penrose-St Francis Healthcare System; Active Staff, Memorial Health System; Clinical Instructor, University of Colorado Health Sciences Center Joel A Ernster is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American College of Surgeons, American Head and Neck Society, American Rhinologic Society, Colorado Medical Society, and Triological Society Coauthor(s): Arturo Avila Chavez, MD, Assistant Professor, Department of Otolaryngology and Head and Neck Surgery, Instituto Nacional De Enfermedades Respiratorias of Mexico City; Douglas Skarada, MD, Consulting Staff, Department of Otolaryngology, Salem Hospital Editors: Clark A Rosen, MD, Director, University of Pittsburgh Voice Center; Associate Professor, Department of Otolaryngology and Communication Science and Disorders, University of Pittsburgh School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Robert M Kellman, MD, Professor and Chair, Department of Otolaryngology and Communication Sciences, State University of New York, Upstate Medical University; Christopher L Slack, MD, Otolaryngology-Facial Plastic Surgery, Private Practice, Associated Coastal ENT; Medical Director, Treasure Coast Sleep Disorders; Arlen D Meyers, MD, MBA, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine Author and Editor Disclosure Synonyms and related keywords: vocal, vocal fold paralysis, vocal cords, vocal cord, bilateral vocal fold paralysis, bilateral vocal cord paralysis, bilateral vocal cord immobility, vocal cord paralysis, bilateral vocal fold immobility, BVFP, BVFI, recurrent laryngeal nerve, cricoarytenoid joint, bilateral vocal fold INTRODUCTIONSection 2 of 12
  Bilateral vocal fold (vocal cord) immobility (BVFI) is a broad term that refers to all forms of reduced or absent movement of the vocal folds. Bilateral vocal fold (cord) paralysis (BVFP) refers to the neurologic causes of bilateral vocal fold immobility (BVFI) and specifically refers to the reduced or absent function of the vagus nerve or its distal branch, the recurrent laryngeal nerve (RLN). Vocal fold immobility may also result from mechanical derangement of the laryngeal structures, such as the cricoarytenoid (CA) joint. Although a small number of conditions account for most cases of vocal cord immobility, this article presents a comprehensive differential diagnosis, followed by the clinical presentations, diagnostic workup, and treatment options. The goal of the article is to provide the clinician with a basic understanding of the rare entity of bilateral vocal fold immobility (BVFI). History of the ProcedureThe history of the procedures used to treat vocal cord immobility begins in 1855 with Garcia's work on mirror laryngoscopy. In the 1860s, Turk and Knight first described vocal cord paralysis. In 1922, Chevalier Jackson performed the first surgical procedure for bilateral vocal fold immobility (BVFP) when he endoscopically resected a vocal cord. He provided an airway at the expense of voice and airway protection. This dilemma continues to plague present surgeons. Since 1922, pioneers in laryngology have described arytenoidectomy, described vocal cord lateralization, and introduced the use of laser. EtiologyAccording to Benninger's findings in a series of 117 cases BVFI can be attributed to the following causes: surgical trauma (44%), malignancies (17%), endotracheal intubation (15%), neurologic disease (12%), and idiopathic causes (12%).1 In adults, conditions that mimic vocal fold immobility include paradoxical vocal fold motion and functional disorder. Causes of vocal fold fixation differ in adults and in children. In adults, these include mechanical causes, inflammatory processes (affecting the CA or larynx), malignancy, surgery, neurologic causes, radiation injury, metabolic causes, and toxins. Mechanical derangement of the posterior glottis may also be referred to as posterior glottic stenosis (PGS). Bogdasarian and Olson classified PGS into the following 4 grades:2
Mechanical causes
Inflammatory processes that affect the CA
Inflammatory processes that affect the larynx
Malignancy
Surgery
Neurologic causes
Radiation injury
Metabolic causes
Toxins
In children, causes of bilateral vocal fold immobility (BVFI) include central neurologic abnormalities, idiopathic causes, and iatrogenic causes. Central neurologic abnormalities Central neurologic abnormalities account for most cases of childhood bilateral vocal fold paralysis (BVFP). Arnold-Chiari deformity with meningomyelocele and hydrocephalus is the most common abnormality. Other CNS insults (eg, infarct, craniotomy, asphyxia) account for some cases, according to the findings in a study by Rosin et al.6 Idiopathic causes Idiopathic causes are the second most common causes of childhood bilateral vocal fold paralysis (BVFP). Some researchers postulate that the etiology in some children with bilateral vocal fold paralysis (BVFI) is an imbalance between the adductors and abductors of the larynx that results in adducted vocal folds. With time, a balance is restored and symptoms abate as children mature. Although conjectural, this explanation fits with the clinical course of most children with bilateral vocal fold paralysis (BVFI) who spontaneously improve with time. Gacek hypothesized that fewer abductor fibers exist; therefore, injury to the nerve is more likely to cause abductor dysfunction.7 He also conjectured that, since abductor fibers are phylogenetically younger than adductor fibers, they may be more fragile. Iatrogenic causes Iatrogenic causes, including mediastinal procedures, cervical procedures, prolonged intubation, and birthing trauma, account for the remaining cases. PathophysiologyAlthough a comprehensive discussion of each of the causes is beyond the scope of this article, some principles should be emphasized. With the first episode of bilateral vocal fold paralysis (BVFP), patients may have dysphonia because the vocal cords are too far apart. Over time, however, the vocal cords can move to a medial position, and the patient may have a good voice and cough despite stridor and bilateral vocal fold paralysis (BVFP). As the vocal cords migrate toward the midline, the voice (and cough) improves, while the airway worsens. Clinicians should not mistake a good voice and cough as signs of a functioning larynx, especially in a patient with stridor. Aspiration and dysphagia may or may not be present in patients with vocal cord paralysis. In terms of the pathophysiology of CA fixation, inflammatory or fibrotic changes can paralyze or reduce the mobility of the joint. Various disorders can cause these changes. ClinicalHistory The importance of a complete history cannot be overstated. The history should include the following:
In children, obtaining a history of birth trauma, central nervous system abnormality, intubations, or surgeries is important. Physical examination The physical examination should include listening to the voice and airway as the patient relays his or her history.
The standard head and neck examination should include careful evaluation of the larynx. Evaluate the following:
INDICATIONSSection 3 of 12
Adults Only the patients with severe bilateral vocal fold (cord) immobility (BVFI) require surgical intervention. Patients with medical conditions (eg, rheumatoid arthritis, Wegener granulomatosis, gout) or neurologic conditions (eg, amyotrophic lateral sclerosis [ALS], Parkinsonism, stroke) rarely require surgical intervention because treatment of the underlying condition often improves airway compromise. For patients with bilateral vocal fold paralysis (BVFP) due to iatrogenic injury in which the recurrent laryngeal nerve (RLN) or vagus nerve is injured (neurapraxia) but not severed, permanent surgical treatment should be postponed for at least 9 months after injury to allow spontaneous recovery. Laryngeal electromyographic (EMG) monitoring can be helpful in obtaining an index of potential recovery. Obtaining a baseline EMG 30-40 days after injury and second EMG 1 month later can help in evaluating the recovery status of the vocal cords (Munin).8 On the basis of the surgeon's clinical judgment, tracheostomy for patients with quickly deteriorating airways should be initiated quickly. For adult patients with bilateral vocal fold (cord) paralysis (BVFP), the literature supports use of an endoscopic approach, with either posterior cordectomy or limited arytenoidectomy as the initial procedure of choice. Suture lateralization may play an adjunctive role. All of these are static permanent procedures; therefore, they should be undertaken only after spontaneous improvement has failed to occur or if EMG findings suggest permanent injury. For patients with bilateral vocal fold immobility (BVFI) caused by PGS, serial endoscopic approaches with scar lysis or microflap trapdoor reconstruction of the interarytenoid (IA) region can be attempted before the static procedures are used. Airway obstruction refractory to the above measures is particularly vexing. Treatment options include laryngofissure with arytenoidectomy, IA reconstruction, posterior cricoidotomy with stent placement, or posterior cricoidotomy with grafting. The literature is less clear concerning the indications for each of these approaches than those of other procedures. Children Surgical intervention is indicated when respiratory effects are significant. Cordopexy or arytenoidopexy, along with partial or complete arytenoidectomy, can help solve the airway problem during the ensuing months or years as one waits for possible recovery of the contralateral cord. Children with bilateral vocal fold paralysis (BVFP) require tracheostomy only when o the airway fails to improve with other measures. Findings of a literature review suggest that the airway can be managed expectantly, without a tracheostomy. Endoscopic management plays a limited role in children and is useful only for mild fixed stenosis and for revisional procedures in children who have undergone open procedures. RELEVANT ANATOMYSection 4 of 12
A review of vagus nerve and RLN anatomy is necessary to understand potential injuries that can cause vocal cord paralysis. The vagus nerve originates in the nucleus ambiguus of the medulla oblongata. At that point, it is composed of cells that receive neural input from the Broca area via decussating corticobulbar tracts; thus it provides input to both the right and left nuclei. Neural input from the cerebellum and extrapyramidal centers, as well as from visceral afferents, provides proprioceptive input that modulates the motor function of the vagus nerve at this site. The motor fibers or visceral efferents that affect the larynx and pharynx occupy 2 specific sites within the nucleus ambiguus. One site becomes the superior laryngeal nerve (SLN); the other, the RLN. The vagus nerve leaves the medulla and enters the jugular foramen, along with the accessory nerve and jugular vein. Within the jugular foramen, the vagus nerve widens to form the superior ganglion, where the cell bodies of the sensory component of the nerve reside (somatic sensory). They provide sensation to the ear canal skin (Arnold nerve). As the vagus nerve exits the jugular foramen, it widens again to form the nodose ganglion, in which nerve cell bodies containing the sensory or visceral afferents from the larynx and pharynx reside. Immediately distal to the nodose ganglion, the SLN exits the vagus nerve and courses along the carotid artery to the larynx, where it enters the larynx through the thyrohyoid membrane, dividing into internal and external branches. The internal branch provides sensory function (visceral afferent), and the external branch provides motor function to the cricothyroid muscle (visceral efferent). The vagus nerve then descends in the neck immediately lateral to the carotid artery. The right RLN fibers exit from the vagus nerve as the nerve crosses anteriorly over the subclavian artery. The RLN loops posteriorly around the subclavian artery to enter the larynx through the Killian-Jamieson area or superior to the fibers of the cricopharyngeal muscle entering the larynx at the cricothyroid space. The left RLN divides much further in the mediastinum, exiting the vagus nerve as it crosses anterior to the aorta and lateral to the ligamentum arteriosum (ie, remnant of the patent ductus arteriosum between the aorta and the pulmonary vein). It then extends superiorly to enter the larynx opposite the right RLN. The RLN branches into the posterior sensory branch and the motor anterior branch to the posterior cricoarytenoid (PCA), IA, lateral cricoarytenoid (LCA), and thyroarytenoid (TA) muscles. The IA muscle is the only motor branch that receives bilateral innervation, which allows some movement of both vocal folds when one RLN is nonfunctional. CONTRAINDICATIONSSection 5 of 12
In adults, any definitive procedure to address vocal cord paralysis, whether unilateral or bilateral, must not be undertaken while a possibility for recovery exists. Recovery can occur as long as 12 months after injury. Every attempt must be made to determine if function is likely to return. This determination should include video direct laryngoscopy, during which the vocal fold can be palpated to assess mobility and bronchoscopy. In addition, laryngeal EMG can be used to evaluate normal action potentials (normal nerve), the absence of potentials (nonfunctioning nerve), defibrillating potentials (worsening nerve), or polyphasic potentials (regenerating nerve). The 12-month wait for return of function can be shortened by obtaining 2 laryngeal EMGs several months apart and by looking for evidence of improved function or stabilized function.8 As many as 70% of children with bilateral vocal fold (cord) paralysis (BVFP) require a tracheostomy. However, spontaneous recovery occurs in half of the patients, sometimes in those as old as11 years. If the condition spontaneously resolves, it typically does so 24-36 months after diagnosis. Therefore, destructive static procedures should be delayed for approximately 3 years because of this potential for recovery. Delaying surgery in children with bilateral vocal fold (cord) immobility (BVFI) caused by PGS is not beneficial; consequently, bilateral vocal fold immobility (BVFI) must be diagnosed correctly in these children to prevent restriction from surgical repair. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
Other Tests
Diagnostic Procedures
TREATMENTSection 7 of 12
Medical therapyMedical management of the inflammatory conditions of the cricoarytenoid (CA) joint (eg, gout) and the laryngeal mucosa (eg, syphilis, tuberculosis) that result in mechanical fixation may improve the patient's airway. Corticosteroids may be effective in several conditions (eg, Wegener granulomatosis, sarcoidosis, polychondritis). Glucose management may help neuropathy due to diabetes mellitus. Reflux management may be helpful in patients with bilateral vocal fold (cord) immobility (BVFI) due to laryngopharyngeal reflux. Surgical therapyProcedures for bilateral vocal fold immobility (BVFI) due to IA scarring with or without CA ankylosis
Procedures for bilateral vocal fold (cord) paralysis (BVFP)
Intraoperative detailsProcedures for BVFIThis discussion does not specifically address surgical management of glottic fixation other than to warn of the difficulty in differentiating between fixation and paralysis in some patients. Procedures for BVFPGeneral algorithm A general algorithm for the treatment of patients with BVFP is the following: If the patient does not require a tracheotomy for a significantly compromised airway, the first procedure can be unilateral posterior cordotomy. The patient is told that this may not provide a sufficient airway, but it has the least adverse effects on his or her voice. The results may need to be revised, or a medial arytenoidectomy may be considered as the next step. Total arytenoidectomy can be performed if necessary. Posterior cordotomy or cordectomy Kashima and Dennis proposed these procedures in 1989.9 Complications are rare. The procedures are effective and easily repeatable in cases of recurrence. Laccourreye recently reported a 92% decannulation rate with this approach in 25 patients.10 The procedure is performed as follows:
Endoscopic limited or complete arytenoidectomy Ossoff et al first described complete arytenoidectomy via an endoscopic approach in 1984.11 Subsequent findings from both dog models and patient series suggest that a complete arytenoidectomy is unnecessary to achieve a high decannulation rate. Eckel et al, however, compared arytenoidectomy with posterior cordectomy and found no difference in effectiveness, but the chance for subclinical aspiration in patients who underwent complete arytenoidectomy was increased.12 The procedure is performed as follows:
Suture lateralization (Ejnell procedure) This technique may be performed alone or with posterior cordectomy, limited arytenoidectomy, or submucosal partial cordectomy. The suture may be placed with the needle inserted from the skin into larynx. This technique is a technically demanding and requires appropriate positioning of the needles and passage of the suture through the needles. The Lichtenberger needle greatly facilitates this approach. This technique may be a reasonable for revision in cases in which additional lateralization of the TVF is desired. The procedure is performed as follows:
Laryngofissure with arytenoidectomy A surgical procedure is warranted for patients in whom vocal fold paralysis persists for several years and who are tracheostomy dependent. Bower et al showed that an external arytenoidectomy via a laryngofissure (originally described by Helmus and later by Singer et al in adults13, 14) provides a superior decannulation rate (84%) compared with that of endoscopic laser arytenoidectomy (56%).15 The procedure is performed as follows:
Postoperative detailsAdults The use of systemic corticosteroids and systemic antibiotics generally are recommended in each of the described endoscopic procedures. Topical fibrin glue may decrease scarring and hasten improved healing at the surgical site. Children After a laryngofissure is created with arytenoidectomy, perform periodic endoscopy to determine the need for decannulation or downsizing the tracheostomy tube. COMPLICATIONSSection 8 of 12
The goal of all the described procedures is to restore a glottic airway despite compromised abductor and adductor function. Altered vocal quality and loss of airway protection resulting in poor cough and aspiration are possible consequences of each of these static procedures. All voice parameters are negatively affected as the airway is improved. Once the voice is affected, returning it to its previous condition often is impossible. These complications develop with varying probabilities based on the degree of airway opening achieved with a specific technique, amount of residual abductor and adductor function, and laryngeal sensation. Specific complications of posterior cordotomy and endoscopic partial or complete arytenoidectomy include granuloma formation, chondritis of arytenoids, carbon dioxide laser–related fire, IA scar formation, possible aspiration, and a breathy voice. OUTCOME AND PROGNOSISSection 9 of 12
Spontaneous recovery can be expected in 55% of patients; almost half of patients who recover do so within the first year. Recovery may occur as late as 11 years after initial diagnosis. All 6 patients treated by Dennis and Kashima with a posterior cordotomy achieved a functional airway without a tracheostomy.9 In 10 of 11 patients in Ossoff et al, a functional airway without tracheostomy was created after complete arytenoidectomy with an endoscopic carbon dioxide laser.11 Remacle et al had the same result in 40 of 41 patients with endoscopic partial arytenoidectomy.16 Eckel et al compared the results of patients treated with posterior cordotomy with those of a group of patients treated with complete arytenoidectomy.12 Both techniques were equally effective for achieving a functional airway, but patients treated with complete arytenoidectomy had more subclinical aspiration. The plethora of etiologies in bilateral vocal fold (cord) paralysis (BVFP) and the multiple interventions do not allow easy comparison of techniques. Most series involving surgical techniques are small, and the findings generally support the authors' biases. Nonetheless, creative surgeons have a number of options that eventually should allow creation of a decannulated and safe airway in most patients. FUTURE AND CONTROVERSIESSection 10 of 12
Several techniques and approaches for the restoration of glottic competence in patients with bilateral vocal fold (cord) immobility (BVFI) are experimental but are promising. They include PCA muscle reinnervation, electrical stimulation of the laryngeal muscles, and use of the Cummings mechanical device. PCA muscle reinnervation Most efforts at laryngeal reinnervation have been focused on patients with unilateral vocal fold paralysis (UVFP). Chhetri et al has recently reported results with a combined procedure in which arytenoid adduction was performed with ansa cervicalis anastomosis to the RLN in a group of patients with UVFP.17 The reinnervation group had no benefit. A group in the Electrical stimulation of the laryngeal muscles Electrical muscle stimulation has been studied for more than 20 years. Current technology permits the creation of implanted laryngeal stimulators. Laryngeal stimulators send a stimulus that can be administered as a continuous current, an intermittent current, or a triggered (preferably by respiratory effort) pacing current. MedTronic has manufactured a number of prototype devices for this purpose, and they are still being researched. In patients with BVFP, laryngeal pacing involves the use of an external apparatus that senses inspiration and reanimates the paralyzed larynx of the patient. Stimuli are delivered through a needle electrode to locate and pace the abductor muscle and through an electrode implanted in the PCA muscle or RLN branch that extends to the PCA muscle. Challenges include imprecise and excessive electrical stimulation, scar formation, bulky power sources, muscle fatigue with continuous stimulation, and difficulty in synchronizing the pacing with the respiratory effort in a convenient way. Researchers express optimism, but technical problems with the electrodes at the muscle site prevent widespread adoption of this technology. Use of the Cummings mechanical device Cummings has reported the use of an implantable device placed into the larynx through a thyroplasty window. This device engages the soft tissues of the larynx (including the TA muscle) with a screw. The screw then is rotated to pull the tissue laterally. Cummings et al conducted the investigation in sheep, with favorable results. Human studies are pending. MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Vocal Fold Paralysis, Bilateral excerpt Article Last Updated: Sep 9, 2008 | ||||||||||||||||||||||||||
