TITLE:
Treatment of Vocal Fold Paralysis
SOURCE: Grand Rounds Presentation, University of Texas Medical Branch
(UTMB Health), Dept. of Otolaryngology
DATE: October 27, 2011
RESIDENT PHYSICIAN: Francisco Pernas, MD
FACULTY PHYSICIAN: Michael Underbrink, MD
SERIES EDITOR: Francis B. Quinn, Jr., MD
ARCHIVIST: Melinda Stoner Qui=
nn,
MSICS
"This material was prepared by
resident physicians in partial fulfillment of educational requirements
established for the Postgraduate Training Program of the UTMB Department of
Otolaryngology/Head and Neck Surgery and was not intended for clinical use =
in
its present form. It was prepared for the purpose of stimulating group
discussion in a conference setting. No warranties, either express or implie=
d,
are made with respect to its accuracy, completeness, or timeliness. The
material does not necessarily reflect the current or past opinions of membe=
rs
of the UTMB faculty and should not be used for purposes of diagnosis or
treatment without consulting appropriate literature sources and informed
professional opinion."
This talk will focus on the treatment of vocal fold paralysis. The objectives are to broadly define hoarseness, discuss the ana= tomy and function of the larynx as well as discuss presenting signs, symptoms, physical exam, ancillary tests that may be obtained to attempt to ascertain= a diagnosis. It will discuss general causes of paralysis and then discuss in depth the treatment of unilateral and bilateral paralysis.
Vocal fold paralysis can be caused by many reasons, the article below will present some of the most common causes and help develop a treatment algorithm to determine the diagnosis and to proceed to treat the patient.
The cartilages of the larynx consist of the thyr= oid cartilage, the epiglottis, the cricoid cartilage, and the arytenoid cartilages. The corniculate a= nd cuneiform cartilages stiffen the aryepiglottic folds. The arytenoid cartilages articulat= e with the cricoid by means of a true synovial joint. This joint allows two movements of= the arytenoid cartilages – rotation and lateral gliding.
There are three groups of intrinsic laryngeal musculat= ure – the abductors, adductors, and tensors. The only abductor of the larynx is= the posterior cricoarytenoid muscle and it is innervated by the recurrent laryn= geal nerve. The adductors are comp= osed of the lateral cricoarytenoid muscle, interarytenoid muscle, oblique aryten= oid muscles, and thyroarytenoid muscles. Innervation of the adductors is again supplied by the recurrent laryngeal nerve. The tensors = are composed of mainly the cricothyroid muscle, which is innervated by the exte= rnal branch of the superior laryngeal nerve, and to a lesser extent by the thyroarytenoid muscles.
The true vocal folds have an epithelial lining that is= composed of respiratory epithelium (pseudostratified squamous) on the superior and inferior aspects of the fold and nonkeratinizing squamous epithelium on the medial contact surface. The subepithelial tissues are composed of a three-layered lamina propria based = on the amount of elastin and collagen fibers.= The superficial layer is composed of mostly amorphous ground substan= ce and contains a scant amount of elastin with few fibroblasts – this la= yer is termed Reinke’s space. The intermediate layer has an increased elastin content. The deep layer has less elastin bu= t a greater amount of collagen fibers. The intermediate and deep layers have a higher concentration of coll= agen fibers and are termed the vocal ligament.&= nbsp; Deep to the lamina propria is the thyroarytenoid (or vocalis) muscle. Reinke’s space = and the epithelial covering are responsible for the vocal fold vibration.
Understanding the anatomy of the vagus nerve is import= ant because branches of the vagus nerve are responsible for innervation of the larynx. The vagus nerve has t= hree nuclei located within the medulla:
The nucleus ambiguus is the motor nucleus of the vagus nerve. The efferent fibers of the dorsal (parasympathetic) nucleus innervate the involuntary muscles of the bronchi, esophagus, heart, stomach, small intestine, and part of the large intestine. The efferent fibers of the nucl= eus of the tract of solitarius carry sensory fibers from the pharynx, larynx, a= nd esophagus.
Vagus means "wanderer" which is appropriate = for the path this nerve takes after emerging from the jugular foramen. It has t= wo ganglia, the smaller superior ganglion and the larger inferior, or nodose, ganglion. The vagus sends small meningeal branches to the dura of the poste= rior fossa and an auricular branch, which innervates part of the external audito= ry canal, the tympanic membrane, and skin behind the ear. In the neck, the vag= us runs behind the jugular vein and carotid artery to send pharyngeal branches= to the muscles of the pharynx and most of the muscles of the soft palate. The superior laryngeal nerve separates from the main trunk of the vagus just outside the jugular foramen. It passes anteromedially on the thyrohyoid membrane where it is joined by the superior thyroid artery and vein (see vasculature). At approximately this level, the external laryngeal nerve lea= ves the main trunk. The main internal laryngeal nerve enters the thyrohyoid membrane through a hiatus. It then divides into three set of branches (ascending, transverse and descending), which communicate with the recurrent laryngeal nerve posterior to the cricoid cartilage; this is referred to as = the ansa galeni. The internal superior laryngeal nerve penetrates the thyrohyoid membrane to supply sensation to the larynx above the glottis. The external superior laryngeal nerve runs over the inferior constrictor muscle to inner= vate the one muscle of the larynx not innervated by the recurrent laryngeal nerv= e, the cricothyroid muscle.
The right vagus nerve passes anterior to the subclavian artery and gives off the right recurrent laryngeal nerve. This loops around= the subclavian and ascends in the tracheo-esophageal groove. It tends to run wi= th the inferior thyroid artery for part of its course before it enters the lar= ynx just behind the cricothyroid joint. It may branch prior to this with sensory fibers supplying sensation to the glottis and subglottis. The left vagus do= es not give off its recurrent laryngeal nerve until it is in the thorax, where= the left recurrent laryngeal nerve wraps around the aorta just posterior to the ligamentum arteriosum. It then ascends back toward the larynx in the TE gro= ove. The vagus then continues on into the thorax and abdomen contributing fibers= to the heart, lung, esophagus, stomach, and intestines as far as the descendin= g colon.
The larynx has a variety of functions. It acts as a sphincter to close the airway during swallowing, preventing aspiration of food and liquids. This is phylogenetically the oldes= t and perhaps most important function of the larynx. Its function is also essential for respiration. Since the larynx= is the gateway to the airway, laryngeal disease may result in obstruction of t= he airway. It functions during communication of both intellectual and emotional expression. Thus, voice deterioration is only = one symptom of laryngeal dysfunction. It also stabilizes the thorax by preventing exhalation, this helps stabilize the arms during lifting. During coughing, lifting, and straining it compresses the abdominal cavity. Aspiration on swallow= ing, ineffective cough, and breathy voice are symptoms caused by the loss of sphincteric function, and can occur in addition to hoarseness in patients w= ith true vocal fold paralysis.
Phonation is defined as the physical act of sound prod= uction by means of passive vocal fold interaction with the exhaled airstream. Basically, this sound production a= rises from a passive movement of the true vocal cords (TVC)s modified in terms of pitch, quality, and volume by complicated interaction of thoracic and abdom= inal muscles, intrinsic and extrinsic muscles of larynx, and the shaping and resonance of the upper airway and nasal passages. Contraction of the expiratory musc= les produces a rise in subglottic air pressure causing rapid escape of air betw= een the nearly apposed TVCs. Bernoulli’s effect and the elasticity of the cords causes medi= al displacement of the medial edges of cords and airflow is stopped. A rapid rise again in subglottic pressure causes the cords to part and the cycle is repeated. It is the escape of small puffs of= air that produces the vibratory phenomenon interpreted as sound.
During phonation the lower margins of the true vocal f= olds separate first with formation of a volume of subglottic air. As the upper margins of the vocal = folds separate a burst of air is released – the glottal puff. The= lower fold then returns to midline, followed by the upper margin. This delay between closure of the = lower and upper margins of the fold is termed the phase delay. The mucosal wave consis= ts of both a horizontal movement of the folds and a vertical undulation.
The body-cover theory helps explain this mucosal wave.= It states that there are two layer= s of the vocal folds with different structural properties. The cover is composed of stratified squamous epithelium and the superficial layer of the lamina propria (Reinke’s space). The b= ody of the fold is composed of the intermediate and deep layers of the lamina prop= ria (which is more fibrous than the superficial layer – the “vocal ligament”) and the thyroarytenoid (vocalis) muscle. The cover is pliable, elastic, and nonmuscular, whereas the body is more stiff and has active contractile properties that allows adjustment of stiffness and concentration of the mass. The mucosal wave occurs primarily in this loose cover of the fold.= Changes in stiffness or tension in the fold alters the mucosal wave. As the stiffness in the= fold increases – as by contraction of the cricothyroid muscle – the velocity of the wave increases and the pitch rises. Mucosal wave velocity also increas= es with greater airflow and greater subglottal pressure.
The pitch of voice is related to the fundamental frequency of vocal fold vibration (measured in hertz). The fundamental frequency of vocal= fold vibration correlates with changes in vocal fold tension and subglottic pressure. Contraction of the = cricothyroid muscles, which correlates positively with vocal fold tension, is the main p= redictor of fundamental frequency, especially at high frequency. Contraction of the thyroarytenoid = may change the tension of the vocal fold cover and body and affect the fundamen= tal frequency also. Three physical properties of the vocal folds determine freq= uency of vibration – mass, stiffness, and viscosity
Mass – the fundamental frequency of vocal fold vibrat= ion is inversely proportional to its mass.&nbs= p; Decreasing the mass – thinning of the fold by longitudinal stretching (contraction of the cricothyroid muscle with elongation of the v= ocal folds) – increases the frequency of vibration. Increasing the mass – contra= ction of the thyroarytenoid muscle with increased concentration of the fold ̵= 1; will decrease the fundamental frequency.
Stiffness – vocal fold tensi= on is an important variable in the control of fundamental frequency at the mechan= ical level. Vocal fold tension is affected by the contractile forces of the vocal fold musculature and the ti= ssue characteristics of the vocal fold body, cover, and the connecting fiber structure of the vocal folds.
Viscosity – Viscosity is inversely related to ease wi= th which the tissue layers slip over one another in response to a shear force. Increased viscosity of= the vocal folds would require greater subglottal pressure to maintain the same vibratory characteristics. Therefore, hydration of the vocal folds has effect on the voice qual= ity and ease of voice production.
Unilateral Vo= cal Cord Paralysis: When one of the vocal cords is paralyzed, the cords are not able to meet in the midline to initiate the glottic attack. This prevents development of the subglottic pressure needed to initiate speech. = Also with the cords at such a dista= nce, the mucosal wave cannot be adequately maintained. Hoarseness and breathiness are the most common complaints but vocal abnormalities may also include easy fatigability and voice or pitch change. It is important not to assume that the immobile cords are necessarily paralyzed. Arytenoid fixation= can lead to an immobile cord and direct palpation of the arytenoid cartilage an= d/or laryngeal EMG can rule out this possibility. Potential return of func= tion of an immobile cord can be determined if the underlying cause is known and = with the aid of LEMG. This contributes significantly to the choice of surg= ical procedure to correct the problem. It is also important to remember th= at the larynx has a number of functions in the human and dysphonia may not be = the primary compliant. Patients may be suffering from dysphagia, coughing= , or choking episodes, or stridor.
There are a number of different causes of unilateral v= ocal cord paralysis. Any entity affecting the vagus nerve along its course= may result in decrease in function. The most common cause is non-laryngeal cancer which includes neoplasms of the head, neck, chest, and skull base.&n= bsp; Neuritis associated with upper respiratory infection, syphilis, or other infectious sources may cause nerve dysfunction. Neurologic conditions such as CVA, multiple sclerosis and myasthenia gravis may also effect vocal cord functioning. General medical conditions such as diabetes mellitu= s Francisco Pernas, MD
may cause an isolated neuropathy giving rise to vocal paralysis. Lesions of the vagal nerve occurring higher in the brain and may present with multiple cranial nerve abnormalities.
Vocal Fold Bowing: The inability of= the folds to approximate at the midline decreases the ability to produce proper speech. Though it may be a normal change in the aging patient, it is = also seen with muscular atrophy secondary to nerve sectioning or central neurolo= gic conditions. With aging, changes in the lamina propria include a loss = of elastic fibers, atrophy of submucous glands, increased fibrosis, and muscle atrophy. These changes result in an increased glottic gap and a numbe= r of perceptual changes. Geriatric patients may present with hoarseness, l= ow pitch, imprecise articulation, or breathiness.
-History:
GENERAL:&= nbsp; As always, obtaining a pertinent history is of utmost importance. One sh= ould determine the onset, duration, and severity of the dysphonia. As previously mentioned, the larynx is also crucial in protecting the lower respiratory tract and is a conduit of the upper respiratory tract. Th= erefore the patient may present with coughing and choking episodes, aspiration, stridor, dyspnea, dysphagia, or odynophagia (2). Intubation his= tory and previous head and neck trauma are crucial pieces of information. = It is important to know if the patient has had any previous laryngeal surgery = or other head and neck surgery.
VOCAL:&nb= sp; A specific vocal history is also important. Many patients who present w= ith vocal complaints have a disease entity that does not warrant surgical treatment. Aside from onset, duration, variability, and past vocal problems, history should include pertinent medical questions such as presence of seas= onal allergies, history of reflux disease, life stress, diabetes, and medications. Many patients who present for an initial evaluation of v= oice complaints are unfamiliar with questions of vocal use and hygiene. It= is important for the physician to explain these concepts to the patient during= the questioning to facilitate accurate responses and educate the patient. Questions should include voice demands at home and at work, recreational singing, and episodes of abuse i.e. sporting events. Smoking, water intake, caffeine intake, and environmental irritants are important questions about vocal hygiene.
-Physical:
It is important to do an entire exam with emphas= is on palpation of the neck to assess for any neck mass or goiter and crani= al nerve testing. An indirect laryngeal exam, as well as a flexible laryngosco= py or videostrobe should be performed. The patient should phonate a high pitched /ee/ sound. This causes elongation of the vocal folds and cau= ses the larynx to move superiorly. These movements aid in obtaining a complete view of the larynx. In addition to assessing vocal fold posi= tion and mobility, it is crucial to rule out carcinoma of the larynx in a patient presenting with hoarseness. A direct laryngoscopy with palpation of t= he arytenoids to ensure joint fixation is absent should be done prior to any surgical procedure.
The manual compression test is an easy non-invasive of= fice procedure to help evaluate a number of voice disorders. The lateral manual compression test is particularly useful in determining whether a pat= ient with a wide glottic gap from unilateral vocal cord paralysis or vocal bowing will benefit from a medialization thyroplasty. To perform the t= est, the neck should be palpated to find the superior notch and the inferior mar= gin of the thyroid ala. The vocal cords are located along a horizontal li= ne drawn at the midpoint of these two landmarks. The patient is asked to sustain an /a/ phonation and pressure is applied to the lateral aspects of = the thyroid cartilage. The concept is to approximate the vocal folds and decrease the glottic gap. A subjective improvement in voice quality is sufficient to state that the patient would benefit from a medialization thyroplasty though acoustic, aerodynamic, and videostroboscopic studies can= be done to quantify improvement. The limitations to this test are older patients who have calcification of the thyroid cartilage, patients with obe= se necks, and patients with scarring of the vocal folds.
-Vocal Assessment:
Despite the recent outburst of technology used to meas= ure and quantitatively assess voice, there is no substitute for the trained ear. Taking a history gives ample time for the physician to make a qualitative assessment of the patient’s voice. Qualities such glottic fry, hard glottal attacks, breathiness, diplophonia, pitch breaks, phonation breaks, and tense phonation can be assessed.
Acoustic evaluation is the quantitative measurement of various voice characteristics. Having the patient sustain a single to= ne, the fundamental frequency (Fo), variations in amplitude (shimmer), and variations in pitch (jitter) can be measured. Fo may be decreased in patients with vocal abuse or poor approximation of the vocal folds. Shimmer alteration is due to decreased stability of the vocal folds. Abnormal jitter correlates with the subjective quality of hoarseness. =
Videostrobolaryngoscopy (VSL) should be performed when= ever possible. It allows for dynamic assessment of the vocal folds. = With this view, the physician is able to differentiate between functional voice problems and those caused by subtle structural abnormalities. Pulses = of light allow us to watch various parts of successive cycles to obtain a comp= lete picture of vocal cord activity. The physician is able to evaluate symmetry of movement, aperiodicity, glottic closure configuration, and horizontal excursion amongst other variables. If the cords are functioning symmetrically, they should essentially be mirror images of each other. The lateral excursion and timing of opening/closing should be identical. Aperiodicity is a measure of irregularities in vocal fold movement. If the frequency of the strobe light is equal to the fundam= ental frequency, no vocal fold movement should be seen. If movement is obse= rved followed by a static period, aperiodicity is present. The glott= is may also be assessed for gap, shape, and appropriate closure (11). The shape of the glottis may be characterized as complete, anterior chink, irregular, bowed, posterior chink, hourglass, or incomplete. Horizont= al excursion is a measurement of the amplitude of the cords. Measurement both pre and post-operatively can provide objective data for evaluating imp= rovement. An additional benefit is reviewing the results with the patient immediately after performing the examination. Giving the patient a visual image of the problem helps considerably in motivation for behavioral treatment and development of goals for improvement.
Electromyography (EMG), though not routinely performed= , is an excellent evaluation of specific muscle functioning. By placing electrodes into laryngeal muscles (thyroarytenoid, cricothyroid), EMGs help elucidate whether there is any re-innervation of muscles which are thought = to be paralyzed. It can also help to differentiate paralysis from aryten= oid joint fixation. EMGs are also used to identify excessive muscle activ= ity prior to the use of BOTOX for spasmodic dysphonia.
-Diagnostic Tests:
If indirect or stroboscopic exam demonstrates a&= nbsp; unilateral vocal cord paralysis with no known etiology, a specific battery = of tests should be considered. A CT scan from skull base to the mediasti= num should be done to evaluate the entire length of the vagus and recurrent laryngeal nerves. If the patient is a child, pregnant, or suspected to have a generalized neurologic problem, an MRI is advised instead. A barium swallow may be done to evaluate swallowing mechanism and associated = dysphagia. Radioactive thyroid uptake scan or ultrasound may be done to evaluate for t= he presence of a nodule or tumor. Chest x-ray is performed to rule out t= he presence of a bronchogenic carcinoma, mediastinal adenopathy/mass, or less likely, the presence of an enlarged heart compressing the recurrent larynge= al nerve, particularly on the left side. A FTA-Abs test should be done to rule out syphilis as a cause of vocal cord paralysis.
In the pediatric population 10% of congenital anomalie= s of the larynx are attributed to vocal fold paralysis It is the second most com= mon cause of stridor in the neonate.Bilateral VFP has been reported to account = for 30–62% of paralyses in children. Most of the time vocal cord paralysi= s in children is due to iatrogenic injury. The leading causes of unilateral VFP = are iatrogenic; cardiothoracic surgery is the most common.Tracheoesophageal fis= tula repair has also been associated with VFP.&= nbsp; (with a12% incidence). Neck Surgery is also a common cause of paraly= sis with surgeries such as branchial cleft excision and thyroidectomy. Arnold&#= 8211;Chiari malformation is the classic c= entral nervous system phenomenon associated with bilateral VFP. Herniating content= s of the posterior fossa exhibit direct pressure on the vagus nerve as it exits = the skull base. Birth trauma (esp w forceps, breach, or vertex delivery) is a recognized but less common cause of bilateral. Other causes: trauma, intubation, cardiovascular anomalies, peripheral neurological disease, and infection including the varicella zoster virus.
The most important aspect of rehabilitating voic= e is defining the patient's goals.
--VOICE THERAPY :
Assessment of patients by a speech pathologist allows = for maximal medical treatment to be implemented before consideration is given to surgical treatment. Some patients develop hyperfunctional compensatory mechanisms which lead to the common complaints of voice strain, neck discomfort, and fatigue (16). Speech pathologists can help eliminate = these habits and educate the patient on proper compensation techniques. Relaxation exercises, aerobic conditioning, voice exercises and other metho= ds are all practiced by the patient to improve voice quality. Once vocal therapy has been maximized and further voice improvement is desired, surgic= al options may be considered. Utilizing voice therapy in treatment of unilateral vocal cord paralysis is crucial to ensuring the greatest improve= ment in voice.
--CORD INJECTION:
Teflon
Collagen
Collagen injections are derived from bovine collagen w= hich is modified to minimize host immune response. Collagen implants are assimilated into the surrounding tissues by an invasion of fibroblasts and deposition of new host collagen. Histologically, the collagen is simi= lar to the deep layer of the lamina propria. Therefore, the collagen is placed within this layer of the vocal fold. Though there is some resorption of the collagen, this is offset by the deposition of host collagen thereby providing long term voice improvement. Resorption of= the collagen may be precipitated by an upper respiratory infection. There have been reports of hypersensitivity reactions with rare cases of airway compromise with the use of Bovine collagen, Zyderm. Some authors still advocate the use of dermal skin tests to test for possible allergic reactio= n to the injections. In a series by Ford and Bless, 2 of 80 patients had a positive skin test which is consistent with the reported incidence of 3%.&n= bsp; Recently, an increased used of Cymetra, a form of collagen composed of micronized homologous alloderm, has decreased the incidence of allergic reactions and lengthened the period of benefit.
Autologous Fat
In 1987, Brandenburg et al. reported the first use of autologous fat injection for glottic insufficiency. Since then, fat injection for a variety of etiologies has become very popular.
Hsiung et al. (12) divided failure into two categories, early and late. With early failure, it was believed that it was due t= o 1) a large glottal gap or 2) a posterior defect not corrected with fat injection. Late failure was attributed to absorption of the fat suppo= rted by an initial improvement in voice quality.
There are still a few concerns and questions about fat injection. Knowing that there will be some reabsorption of the fat, t= he cord needs to be overinjected. This leads to the question of exactly = how much fat results in an optimal change in voice. It is also not known whether improved vocal function is due to the amount of fat injected or&nbs= p; softening of the vocal cords. Another uncertainty is the rate of fat absorption by the vocal tissue. If initially effective, the benefits = of fat injection may last anywhere from three months to several years. S= ome studies have shown that despite absorption of the fat, lipocytes and fibrous connective tissue retain the contour of the vocal cord and provide long term benefit. The exact method of harvesting and preparation of the fat and its relation to absorption is still unknown. Effort should be made to minimize that amount of trauma to the fat during extraction.
Synthetic Injectables:
Calcium Hydroxyapatite (Radiance FN; BioForm) is an inject= able material made of small spherules of CaHydroxyapatite. No granuloma formation occurs with= this agent. Long term efficacy is = currently under study.
Polydimethylsiloxane gel (Bioplastique; Bioplasty) is widely used in Europe for vocal fold medialization, but is not approved for use in the U.S. = Sustained phonatory improvement up to 7 years has been shown in some European studies= .
--TYPE I THRYOPLASTY
-Variations/Controversies:
Removal of the cartilage window: Some authors feel that the cartilage, if left in place can migrate superiorly and medialize the false vocal cord or ventricle.&nbs= p; If the cartilage migrates inferiorly, it may cause overmedialization of the cord resulting in a persistently strained voice quality.
Inner pericho= ndrium: Some authors prefer to leave the inner perichondrium intact stating that it decr= eases the incidence of graft extrusion. Netterville states that the reason = for increased implant extrusion is injury to the ventricle. This occurs m= ore frequently if a paramedian incision is used near the anterior commissure wh= ere the ventricle is located very close to the inner perichondrium. He ar= gues that incising the inner perichondrium does not increase implant extrusion secondary to the development of a fibrous capsule around the implant.
Implant mater= ial: Though some authors feel that a carved implant allows for precise results, Montgom= ery et al. (10) reports certain benefits to a pre-made implant. The inner aspect, which medializes the cord, is made of a softer plastic closer to the consistency of the surrounding tissue. The outer half is made of a ha= rder plastic which locks into the thyroid cartilage. This prevents displacement of the cords and eases revision. Hydroxylapatite is a pre-made implant which has minimal tissue reactivity and good biocompatibil= ity with the surrounding tissue. Gore-tex (ePTFE) is another material reported to be of benefit in medializing a paralyzed vocal cord. This material has excellent biocompatibility and can be used to medialize the co= rd in an incremental fashion. This technique does not require extreme pr= ecision in creating the thyroid window or shaping the implant.
--ARYTENOID ADDUCTION:
There are two major indications for an arytenoid adduc= tion. The first reason is to close a posterior glottic gap. Given that the cricoid overlaps the thyroid posteriorly, a posterior window is not effecti= ve in medializing the posterior vocal cord. The traditional Type I thyroplasty has been shown to be ineffective in medializing the posterior cord. A simple way to assess if an arytenoid adduction is necessary i= s to see if the vocal processes of the arytenoid cartilages touch in the midline when the patient phonates. The second reason is if the vocal folds are not at the same caudal-rostral level. The vocal process of the aryten= oid cartilage moves inferior with adduction and superior with abduction. = This is due to the cylindrical shape of the cricoarytenoid joint. Some surgeons advocate an intra-operative assessment of the vocal cord medialization. If after the silastic implant has been placed, there i= s a persistent posterior gap, an arytenoid adduction is performed.
The procedure is described as it is performed by Isshiki. Using a horizontal neck incision at the level of the vocal cords, the posterior border of the thyroid cartilage is exposed by transect= ing the strap muscles and detaching the inferior constrictor from the thyroid. It is important to identify the recurrent laryngeal nerve in= this area to avoid any damage. The cricothyroid joint is then opened to al= low access to the muscular process of the arytenoid cartilage. The pirifo= rm sinus mucosa is then elevated with great care to violating the piriform rec= ess. Cricoarytenoid joint is then opened allow exposure of the muscular process. The posterior cricoarytenoid muscle is identified and ligated from the muscular process. Two 3-0 nylon sutures are placed around the muscular process and the surrounding soft tissue. The sutures are then pulled anteriorly through the thyroid ala. The patient is asked to phonate and the appropriate force is determined to provide optimum voice results.
The only significant variation is whether or not to op= en the thyroarytenoid joint. Some authors believe that opening the joint res= ults in prolapse of the arytenoid cartilage into the laryngeal lumen with overadduction of the posterior commissure.
Arytenoid adduction can be used in conjunction with medialization thyroplasty and re-innervation surgery. Currently, no o= ther procedure corrects for a discrepancy in vocal cord level and few other procedures effectively address a wide posterior chink.
--REINNERVATI= ON SURGERY WITH ANSA CERVICALIS:
A universal criticism of reinnervation is the 4 to 6 m= onth period required for the procedure to be effective. Many authors advoc= ate the concurrent use of a medialization procedure, either Gelfoam injection or thyroplasty. Tucker has described removing the posterior inferior asp= ect of the implant in order to allow room for the muscle-pedicle implant to be placed.
When comparing the two methods of reinnervation, it is currently unclear which procedure produces the best results. Prelimin= ary work by Hall et al. indicates that the muscle pedicle allows for more rapid innervation and stronger contractile force. Current research is direc= ted toward understanding the role of cell adhesion markers in the role of nerve regrowth. This research will likely have a significant impact on the methods of reinnervation surgery.
Recently a modification has been proposed to the recur= rent laryngeal nerve – ansa recurrent laryngeal anastomosis procedure. Paniello (16) has proposed a recurrent laryngeal – hypoglossal nerve anastomosis. The theoretical advantage is that these are the only two nerves involved in swallowing and phonation. Other advantages are an abundance of axons in the hypoglossal nerve, use in patie= nts in which ansa is unavailable, and low donor site morbidity. Initial w= ork with the procedure suggests that it results in a stronger reinnervation and sphincter-like action on swallowing. Though there is denervation of t= he ipsilateral tongue, no increase in aspiration has been shown
In contrast to unilateral vocal cord paralysis, voice quality is not the primary concern in patients with bilateral vocal cord paralysis. The significant problem is airway compromise. This can range from unnoticeable to, more commonly, dyspnea and stridor. The patient's voice quality is usually only mildly affected (if just the recurrent laryngeal ne= rves are involved) because the paralyzed cords tend to assume the natural positi= on for phonation.
There are three basic ways that bilateral vocal cord paralysis is managed:
Tracheotomy has the advantages of providing immediate = relief of airway restriction. It can= be performed under local anesthesia, and has relatively little reduction in vo= ice quality. Disadvantages include the creation of a stoma that has both cosmet= ic and long-term care problems, and the need to occlude the tube or wear a speaking valve to phonate. This may be the best option for many patients because it controls the airway while preserving voice quality. In many pati= ents, the tracheotomy can be occluded the majority of the time. In times of exert= ion, while sleeping, or when the patient has a cold or other respiratory conditi= on, the tracheotomy can simply be unplugged.
This involves several techniques that surgically widen= the glottic opening. While this improves the airway, the patient's voice quality suffers. The three most commonly utilized techniques are arytenoidectomy, arytenoidopexy, and cordectomy/cordotomy.
Classic arytenoidectomy involves removal of some or al= l of the arytenoid cartilage. This procedure can be performed in a variety of wa= ys, from endoscopically by microsurgical or laser technique to an external, lat= eral neck approach (Woodman). The Woodman procedure involves a lateral neck incision, exposure of the arytenoid cartilage posteriorly with removal of t= he majority of the cartilage, sparing the vocal process. A suture is then plac= ed into the remnant of vocal process and fixed to the lateral thyroid ala. This technique seems to cause less voice deficit than other approaches.
Arytenoidopexy:
Arytenoidopexy displaces the vocal fold and arytenoid without surgical removal of any tissue. It can be done endoscopically with a suture passed around the vocal process of the arytenoid and secured lateral= ly. This procedure, however, has a relatively high failure rate and is technica= lly difficult.
Dennis and Kashima (1989) introduced the posterior par= tial cordectomy procedure using the carbon dioxide laser. This involves excising= a C-shaped wedge from the posterior edge of one vocal cord. If this posterior opening is not adequate after 6-8 weeks, the procedure can be repeated or a small cordectomy can be performed on the other vocal cord. Laser cordotomy removes a smaller posterior portion of the true vocal cord and better preserves voice.
Tucker proposed a nerve-muscle transfer to the posteri= or cricoarytenoid muscle for the treatment of bilateral vocal cord paralysis. = The technique is similar to the one used for unilateral vocal cord paralysis. Prerequisites are that the cricothyroid joint not be fixed and that the necessary nerve for the graft not have been affected by the process that ca= used the paralysis. Tucker reports a high success rate.
Positio=
n of
Vocal Fold
Initially the position of the vocal fold was thought t= o be related to site of injury. RLN versus vagal (RLN + SLN) Paramedian =3D RLN = injury.Lateral =3D RLN + SLN injury Cricothyroid muscle (SLN) was believed to influence the vocal fold position in laryngeal paralysis. In a study by Koufman 27 Pts wi= th unilateral VF Paralysis underwent FOL and LEMG. VF positions were paramedia= n in 8 patients, intermediate in 7, and lateral in 11. LEMG, 13 patients had isolated recurrent laryngeal nerve lesions and 13 patients had combined (superior and recurrent laryngeal nerve) lesions. No correlation between the vocal fold position and the status of the cricothyroid muscle.
Early Versus Late VC Injection
There has been a longstanding debate on the timing of performing a medialization thyroplasty. In this article by Friedman et. al. there was association between early vocal cord injection & reduced need for open-neck larynge= al medialization. Early medialization was more favorable VC position for phona= tion maintained by synkinetic reinnervation. The authors advocate early interven= tion by demonstrating that there was a reduction in the number of procedures that patients who were injected early in their course.
Bilater=
al
Medialization Thyroplasty
There are several differences between a unilateral laryngoplasty and a bilateral procedure:
· Overcorrection anteriorly must be avoided, s= ince this will cause a harsh, strained voice.
· The posterior flange of the implant must not contact the arytenoid cartilage. (This requires implants that are shorter in the anterior-posterior dimension when compared with “standard” implants)
In this article by Koufman et.al. bilateral laryngo= plasty appears to be a safe and effective treatment for patients with glottal incompetence attributable to a wide array of causes, especially if aspirati= on is present. Patients with degenerative neuromuscular diseases, however, do = not appear to benefit as much from this procedure as do individuals with paresi= s or presbylaryngis.
Mediali=
zation
versus Reinnervation
In this study by Piccirillo patients with unilateral VF paralysis were randomized into two groups:Patients randomized to the ML gro= up, surgeons performed whichever medialization procedure they would have perfor= med if the patient were off-study. The reinnervation procedures were all perfor= med using ansa cervicalis-to-RLN anastomosis. In one case, it was found that the planned anastomosis could not be performed for technical reasons, and a medialization was performed instead. At 12 months, both study groups showed significant improvement in several scores. No significant differences were fou= nd between the two groups. However, patient age significantly affected the LR,= but not the ML, group results. Patients older than 52 did better with medializa= tion versus re-innervation.
Laryngeal Reinnervation
Techniques
In this meta-analysis 14 studies (329 patients were an= alyzed). The results revealed an average of 50.2% men, mean age of 51yr (range, 12-79 yrs). The most common technique was ansa cervicalis-to-RLN, most commonly performed after thyroidectomy (43.5%). Other techniques:
Primary RLN anastomosis, ansa-to-RLN combined with cricothyroid muscle-nerve-muscle pedicle, ansa-to-thyroarytenoid neural implantation, ansa-to-thyroarytenoid neuromuscular pedicle, Hypoglossal-to-= RLN. Their conclusion was mean time to first signs of reinnervation was 4.5 mont= hs. Visual analysis of glottic gap showed the greatest mean improvement with ansa-to-R= LN. Reinnervation is effective in the management of UVFP, although the specific method may be dictated by anatomical limitations.
That was a very nice talk on
laryngeal paralysis, Dr. Pernas, covering an area in which treatment is not
often straightforward, One wa=
y to
classify these patients is according to whether they need correction of the=
ir
disability early or can they wait until later, when the situation is perhaps
more clear. If in the case of=
a
surgical section of the nerve, or if they are aspirating, it may be better =
to
embark earlier on correction of the functional deficit. Then it becomes a matter of
matching the correction to the needs and expectations of the patient. Your examination findings, especia=
lly
with regard to a posterior gap, can be controlling.
What I try to do now is to off=
er
them an initial trial with voice gel in the clinic, because it works really
well and it's not that invasive and you can get a very good voice for about
three months and let them decide on what kind of permanent solution they may
wish.
Arytenoid adduction is a great
concept (arytenoidopexy?) but you have to do that operation in an awake pat=
ient
in a very select group of patients and it takes longer and they are on the
table longer. Also, it's not =
very
comfortable to have to be on the table for two or three hours for a
thyroidopexy . Once you start=
to
pull the larynx over, that can be quite uncomfortable. You're going to be removing part o=
f the
perichondrium , also very uncomfortable.&n=
bsp;
If you try to do it on an anesthetized patient, it just doesn't
work.
The re-inervation procedure is
interesting and I like to offer that.
Most patients don't want to wait three to four months for their func=
tion
to come back . It's a great
opportunity for younger patients who can compensate well in cases where you
have the stump of the recurrent nerve to anastomose. However, in patients with prior
thyroidectomy or radiation, a
muscular pedicle can work just fine. =
You don't get movement of the vocal cord, you get tone and tone is
enough. It may not be g=
ood
enough in a patient with a large posterior gap
Portions contributed directly from
Wilson, Deborah, “Vocal Cord Paralysis,” Quinn Grand Rounds
Archive, Nov 15, 1995;
http://www.utmb.edu/otoref/Grand_Rounds_Earlier.dir/Vocal_C=
ord_Paralysis_1995.txt
and
Divi, Venu, “Treatment of Unilateral Adductor Vocal Cord
Paralysis,” Nov 8, 2000
and
http://www.utmb.edu/otoref/grnds/VC-paralysis-001108/VC-paralysi=
s-001108.pdf
and
“Vocal Cord Paralysis and Vocal Cord Medialization” Archive by =
Shashidhar
S. Reddy, MD, MPH on April 28, 2004.
http://www.utmb.edu/otoref/grnds/Vocal-cord-040428/Vocal-cord-040428=
.pdf
1. Cummings, CW. Phonosurgical procedures. Otolaryngology – Head and Neck Surgery 2nd edition. = St. Louis. 1993. 2072 – 2100.
2. Colton RH, Casper JK. Surgical and medical management = of voice disorders. Understanding Voice Problems. 2nd edition.&nbs= p; Baltimore. 1996. 241 – 270.
3. Fried MP. Rehabilitation of the immobile vocal fold: paralysis and/or fixation. The Larynx: a multidisciplinary approach. 2nd edition. St. Louis. 1996. 209 – 219.
4. Lu F, Casiano RR, Lundy DS, Xue JW. Vocal evaluation of thyroplasty Type I in the treatment of nonparalytic glottic incompetence.&n= bsp; Ann Otol Rhinol Laryngol 1998; 107: 113 – 119.
5. Omori K, Slavit DH, Kacker A, Blaugrund SM. Quantitati= ve criteria for predicting thyroplasty type I outcome. Laryngoscope 1996; 106: 689 – 693.
6. Netterville JL, Stone RE, Luken ES, Civantos FJ, Ossoff RH. Silastic medialization and arytenoid adduction: the Vanderbilt experience. A review of 116 phonosurgical procedures. Ann Otol Rhinol Laryngol 1993; 102: 413 – 424.
7. Isshiki N. Vocal mechanics as the basis for phonosurgery. Laryngoscope December 1998; 108: 1761 – 1766
8. Isshiki N, Tanabe M, Sawadw M. Arytenoid adduction for unilateral vocal cord paralysis. Arch Otolaryngol 1978; 104: 555 R= 11; 558.
9. Koufman JA. Laryngoplasty for vocal cord medialization= : an alternative to Teflon. Laryngoscope July 1986; 96: 726 – = 731
10. Thompson DM, Maragos NE, Edwards BW. The study of voc= al fold vibratory patterns in patients with unilateral vocal fold paralysis be= fore and after Type I thyroplasty with or without arytenoid adduction. Laryngoscope May 1995; 105: 481 – 486.
11. Chhetri DK, Gerratt BR, Kreiman J, Berke GS. Combined aryte= noid adduction and laryngeal reinnervation in the treatment of vocal fold paralysis. Laryngoscope December 1999; 109: 1928 – 1936
12. Hsiung M, Woo P, Minasian A, Mojica JS. Fat augmentat= ion for glottic insufficiency. Laryngoscope 2000; 110: 1026 – 1033<= /p>
13. Isshiki N, Morita H, Okamura H, Hiramoto M. Thyroplasty as a new phonosurgical technique. Acta Otolaryng 1974; 78: 451 – 457.
14. Benninger MS, Alessi D, Archer S, Bastian R, Ford C, Koufma= n J, Sataloff RT, Spiegel JR, Woo P. Vocal fold scarring: current concepts= and management. Otolaryngology – Head and Neck Surgery 1996; 115: 4= 74 – 482
15. Paniello DC. Laryngeal reinnervation with the hypoglo= ssal nerve: XII. Clinical evaluation and early patient experience. Laryngoscope 2000; 110: 739 – 747.
16. Benninger MS, Crumley RL, Ford CN, Gould WJ, Hanson DG, Oss= off RH, Sataloff RT. Evaluation and treatment of the unilateral paralyzed vocal fold. Otolaryngology - Head and Neck Surgery 1994; 497 – 508.
17. Tucker HM. Long-term preservation of voice improvement following surgical medialization and reinnervation for unilateral vocal fold paralysis. Journal of Voice 1999; 13: 251 – 256.
18. Olson DE, Goding GS, Micheal DD. Acoustic and percept= ual evaluation of laryngeal reinnervation by ansa cervicalis transfer. Laryngoscope 1998; 108: 1767 – 1772.
19. McCulloch TM, Hoffman HT. Medialization laryngoplasty with expanded polytetrafluoroethylene. Ann Otol Rhinol Laryngol 1998; 107: 427 – 432.
20. Isshiki N, Kojima H, Shoji K, Hirano S. Vocal fold atrophy and its surgical treatment. Ann Otol Rhinol Laryngol 1996; 10= 5: 182 – 187.
21. Eliachar I, Myles J, Munoz-Ramirez H, Strome M. Histopathologic study of alternative substances for vocal fold medialization. Ann Otol Rhinol Laryngol 2000; 109: 221 – 227.
22. Dulguerov P, Schweizer V, Caumel I, Esteve F. Medialization laryngoplasty. Otolaryngology – Head and Neck Sur= gery 1999: 275 – 278.
23. Montgomery WW, Blaugrund SM, Varvares MA. Thyroplasty= : a new approach. Ann Otol Rhinol Larngol 1993; 102: 571 – 579.
24. Benninger MS, Gillen JB, Altman JS. Changing etiology= of vocal fold immobility. Laryngoscope September 1998; 108: 1346 – 1350
25. Kelchner LN, Stemple JC, Gerdeman B, Borgne WL, Adam S.&nbs= p; Etiology, pathophysiology, treatment choices, and voice results for a unilateral adductor vocal fold paralysis: a 3-year retrospective. Jou= rnal of Voice 1999; 13: 592-601
26. Pou AM, Carrau RL, Eibling DE, Murry T.&n= bsp; Laryngeal framework surgery for the management of aspiration in high vagal lesions. American Journal of Otolaryngology : 1998; 1 – 7
27. Kojima H, Hirano S, Shoji K, Isshiki N. Anatomic study for posterior medialization thyroplasty. Ann = Otol Rhinol Laryngol 1999; 108: 373 – 376
28. Blaugrund SM, Taira T, El-Assuooty A, Lin= P, Isshiki N, Gould WJ. Effects of lateral manual compression upon glott= ic incompetence: objective evaluations. Ann Otol Rhinol Laryngol 1990; 9= 9: 249 – 255.
29. Maragos NE. The posterior thyroplasty window: anatomical considerations. Laryngoscope August 19= 99; 109: 1228 – 1231.
Tucker, HM. Anatomy of the Larynx. In: Tucker, HM. The Larynx. New Yo= rk: Theime Medical Publishers, 1993
30. Cohen, SR, et al. Laryngeal Paralysis in Children. Ann Otol Rhinol Laryngol 1982; 91:417-423.=
31. Dennis, DP and Kash= ima, H. Carbon Dioxide Laser Posterior Cordectomy for Treatment of Bilateral Voc= al Cord Paralysis. Ann Otul Rhinol Laryngol 1989; 98:930-934.
32. McGill, TJ. Congeni= tal Abnormalities of the Larynx. In: Fried, MP. The Larynx. A Multidisciplinary Approach. Boston, Toronto: Little, Brown and Company, 1988.
33. Terris, DJ, et al. Contemporary Evaluation of Unilateral Vocal Cord Paralysis. Otularyngol Head Neck Surg 1992; 107:84-89.
34. Miller, RH and Rosenfield, DB. The Rule of Electromyography in Clinical Laryngulogy. Otolaryngol Head and Neck Surg 1983; 92:287-291.
35. Koufman, JA and Isa= acson, G. Laryngoplastic Phonosugery. Otularyngologic Clinics of North America 199= 1; 24: 1151-1177.
36. Tucker, HM. Rehabilitation of the Immobile Vocal Fuld: Paralysis or Fixation. In: Fried, MP. The Larynx. A Multidisciplinary Approach. Boston, Toronto: Little, Brown and Company, 1988.
37. Miller, RH and Rosenfield, DB. Hoarseness and Vocal Cord Paralysis. In: Bailey, BJ, et al,= eds. Head and Neck Surgery - Otolaryngology. Philadelphia: J.B. Lippencott, 1993= .
38. Willatt, DW and Ste= ll, PM. Vocal Cord Paralysis. In: Paparella, MM, et al, eds. Otolaryngology. Philadelphia: W.B. Saunders, 1991.
Bryan, MD and Quinn, FB. Vocal Cord Paralysis. Grand Rounds Presentat= ion, Sept, 1994. UTMB, Galveston http://www.utmb.edu/otoref/Grand_Rounds_Earlier.dir/Vocal_C= ord_Paralysis_1994.txt
39. Tucker, HM. Neurulo= gic Disorders and Phonosurgery for Voice Disorders. In: Tucker, HM. The Larynx.= New York: Theime Medical Publishers, 1993.
40. Remacle, Marc et al Injectable substances for vocal fold augmentation, Current Opinion in OtoHN= S: Dec 2001: 9(6) pp 393-3= 97
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