-------------------------------------------------------------------------------- TITLE: Voice Disorders and Phonosurgery SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: May, 1991 RESIDENT PHYSICIAN: Sharen K. Knudsen, M.D. FACULTY: Byron J. Bailey, M.D. DATABASE ADMINISTRATOR: Melinda McCracken, M.S. -------------------------------------------------------------------------------- "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 implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." Voice Disorders and Phonosurgery I. Phonation A. The larynx is the organ of phonation. Refer to the May 23, 1990 grand rounds presentation for excellent review of laryngeal anatomy and physiology. 1. Functions of the larynx include: respiratory, airway protection, swallowing, pressure valving and phonation 2. Phonation: The larynx acts as a sound generator by rapidly opening and closing the airway and interrupting the breath stream. a. Initiated by an increase in subglottic pressure caused by adducted vocal folds during exhalation. b. When subglottic pressure is sufficiently increased, the vocal folds are "blown apart" c. The elastic properties of the larynx and resting adduction forces reapproximate the vocal folds. d. This cycle is repetitive and cycles about every 10 milliseconds. 3. Physics of speech: a. Subglottic pressure drives the cords open, this aeorstatic force is maximum at the beginning of each cycle. b. Bernouli Effect: the relationship between pressure and velocity is an inverse relationship. The pressure is least where flow is greatest (i.e. the glottis). Subglottic anatomy is configured to produce a bernouli effect at the glottis. The cone shaped narrowing increases the air flow and decreases the pressure at the glottis; then, the glottis has a relative negative pressure which draws the cords together. c. The elastic properties of the vocal folds permit aerodynamic forces to cycle. The tension in the vocal ligaments restore the focal folds to their original adducted position. The elasticity can be modified by two means: Stretching the folds or by changing the stiffness with contraction of the vocal muscles. 4. Theory: a. Ferrin (1741) experiment on animal larynges demonstrated that the vibration of the vocal folds responsible for voice. Bow string analogy. b. Helmohltz (1863) phonation a product of puffs of air released by glottis. c. Van-den-Berg (1958) postulated the mass- tension forces of the larynx interacting with the aerodynamic forces of the breath stream produce voice. Myoelastic-Aerodynamic Theory d. Husson (1953) postulated rhythmic contractions of the thyroarytenoid muscles occur at the fundamental frequency. Neurochronaxic Theory. Disproved. II. Voice A. Fundamental Frequency: An acoustical property. The lowest frequency is the fundamental frequency, and all other frequencies are multiples of this fundamental frequency and are called overtones. 1. Fundamental Frequency decreases with age, and parallels the descent of the larynx in the neck. The most notable changes occur between birth and puberty. In the average male, the Fo is 120 Hz, and in females Fo is 214 Hz. 2. In the aged, the Fo again increases. B. Vocal Intensity is subjectively perceived as loudness, and increases as the subglottic air pressure increases. C. Frequency or pitch (a perceptual correlate) increases a function of three factors: a. increased subglottic pressure b. shortening pharyngeal dimensions by raising larynx in the neck c. increase in vocal fold length and tension D. Register is a psycho-acoustic property, a normal voice is recognized, and this is called modal register. A normal voice quality is present across a pitch range. When a smooth transition between pitch is not made, this indicates entry into a new register. The lowest registers called glottal fry, or pulse register. The highest is called falsetto or loft register. II. Voice Disorders due to Mass Effect A. Disorders due to mass effect produce one or more of the following pathologic changes: 1. increase bulk or mass or vocal folds or surrounding tissues 2. alter shape of vocal folds 3. restrict mobility 4. alter tension 5. alter shape of the endolarynx 6. prevent approximation B. Specific lesions 1. papilloma 2. inflammation (croup or acute laryngitis) 3. laryngitis sicca 4. malignant tumors 5. vocal nodules 6. contact ulcers or granuloma 7. myxedema of hypothyroidism 8. amyloidosis 9. vocal polyp 10. polypoid chorditis C. The perceptual voice changes resulting from a mass lesion are excessive breathiness, aphonia, and both high and low pitch perturbations. III. Disorders due to Neurologic Disease A. Generally related to insult to parts of the nervous system that are part of phonatory mechanism. These can be vascular, infectious, traumatic, neoplastic, or degenerative in origin. B. Technically these are dysarthrias. C. Types: 1. Flaccid dysarthria: example is myasthenia gravis characterized by hypernasality due to failure of palate to close, and by a breathy weak voice. This worsens as the voice is fatigued. The basis is flaccid vocal folds producing turbulence and increased volume in the glottis along with failure to develop complete closure of glottis during the cycle. 2. Spastic (pseudobulbar) dysphonia: example are pyramidal lesions in the CNS. Phonation is hoarse or harsh, pitch is low and monotonous, loudness is reduced. Inappropriate crying or laughter may be present. Voice quality produced by hyperadduction of the vocal folds with resultant glottic constriction. 3. Mixed dysarthria: example is ALS with both upper motor neuron and lower motor neuron damage. Components of both flaccid and spastic dysarthria are noted. Phonation has a wet or gurgly quality. Flutter or voice tremor is noted. 4. Hypokinetic dysarthria: example is Parkinsonism. The voice quality is monopitch, reduced loudness, with both harsh and breathy sounds. This can be the earliest sign of parkinsonism. 5. Hyperkinetic dysarthria: example is dysphonia of essential tremor. Quavering, intermittent voice arrests during speech. Vocal folds appear normal in structure, on vowel sounds adductor-abductor oscillations synchronous with tremor are seen. D. Miscellaneous information: 1. Infants with neurologic disease cry abnormally. 2. Ever-present is the danger of misdiagnosing of neurologic dysphonia as being psychogenic in origin, possibly overlooking early clue to organic disease. 3. Aberrations in melody called dysprosody of pseudo- foreign dialect seen with CNS lesions give impression of foreign dialect. 4. Muteness, apraxia, palatomyoclonus, Gilles de la Tourette syndrome are all examples of organic dysphonias. IV. Psychogenic Voice Disorders A. Well known that voice is an indicator of emotion. B. Affective disorders noted for loud, pressured speech during mania and soft, monotonous speech during depression. C. Vocal abuse in children and adults can produce inflammation, vocal nodules and contact ulcers. It is important to think that vocal abuse disorders as secondary to an emotionally determined impetus to vocalize aggressively. D. Musculoskeletal tension can produce tissue trauma to the vocal folds resulting in a contact ulcer. The dysphonia is usually low pitched, hoarse, and grating. E. Ventricular dysphonia (dysphonia plicae ventricularis) is characterized by a harsh or hoarse low pitched voice. Voice is produced by the vibration of the false cords. F. Mutational Falsetto is failure to change from the high pitched voice of a child to the lower pitched voice of an adolescent or adult. The qualities are thin, effeminate, and immature. It is important to realize this is not due to immaturity of the larynx. V. Spastic Dysphonia: two types recognized: adductor and abductor according to Aronson (1985). A. Adductor spastic dysphonia is characterized by a strained, groaning voice full of effort. 1. The voice is produced by hyperadduction of the true and often the false cords. In addition the extrinsic muscles of the larynx contract and elevate the larynx in synchrony with the spasms. 2. It is controversial whether the origin is psychogenic or neurologic in origin. Perhaps conversion reaction and musculoskeletal tension account for some cases and a localized neurologic dystonia account for others. 3. Known neurologic disorders which produce this quality of voice are: Meige's syndrome (oralfacial dystonia), essential tremor, spastic torticollis. These are considered extrapyramidal diseases. Onset is in the fifth through sixth decades, usually associated with emotional stress. 4. Regardless of the cause, serious occupational, social, and emotional disturbances are sequelae of this disorder. B. Abductor spastic dysphonia is a term that describes the abrupt breathy releases of air owing to sudden hyperabduction of the vocal folds. 1. The spasms occur during the production of unvoiced consonants, and rarely occur during vowel phonation. 2. The onset is gradual, and often associated with emotional distress. VI. Laryngeal Surgery - Phonosurgery A. Vocal Fold Injections 1. Historical Perspective a. 1911 Brunning injected paraffin, the results were initially good, but long term patients developed granuloma (paraffinoma). b. 1955 Arnold injected cartilage particles. c. 1962 Arnold injected teflon with good result and little inflammatory reaction. Used for years as the standard for unilateral vocal cord lesions. d. 1985 Ward used a transcutaneous technique. e. 1978 Schram and May used Gelfoam injection for temporary medialization f. 1986 Ford and Bless injected collagen g. 1987 Cohen injected botulinum toxin in vocal cords for relief of abductor vocal cord paralysis. 2. Intracordal Injections - Technique a. Indications: unilateral vocal fold paralysis, with glottic chink less than 3mm. b. local anesthesia with observation of phonation during procedure. c. with patient in supine position, a laryngoscope is introduced and positioned to visualize the lateral true cord. d. needle is placed laterally in the ventricle, object is to introduce material lateral to the thyroarytenoid muscle and into the TVC close to the thyroid cartilage. e. Three injections are made: (1) two are made roughly dividing the cord in thirds (2) optional third injection made anterior to vocal process. 3. Benefits a. Cough, voice, valsalva are increased b. aspiration decreased c. inexpensive d. done under local with no open wounds 4. Risks a. Airway compromise 6/262 in one series b. Granuloma c. Injections at different levels in each cord results in uneven cords which produces weak voice. Injections too deep go into subglottic d. Perichondritis e. Migration 5. Modifications: a. Gelfoam - technique which is ideal for temporary paralysis, when recovery is anticipated. Duration is 6 weeks to several months. Resorption leaves little scarring. b. Collagen - Injection not as deep as with teflon. Must test for hypersensitivity reaction. Need to overcorrect as some resorption does occur. Advantage is that collagen is natural component of vocal fold. Disadvantage is that resorption does occur. c. Botulinum toxin - used to treat adductor spasmodic dysphonia. 25-30 U are injected through the cricothyroid membrane angled laterally and superiorly. Confirmation is made by EMG recording in the thyroarytenoid muscle. Effects can endure for up to four months. Best in patients with a tremor component to dysphonia. d. Transcutaneous technique described by Ward offers advantage of using upright position and visualization of the larynx during injection without direct laryngoscopy. B. Laryngeal Framework Surgery 1. Historical Perspective a. 1915 Payr used a tilted U shaped incision on the thyroid ala to make a pedicled cartilage flap which was depressed inward displacing the vocal cord medially. b. 1952 Muerman transplanted autogenous costal cartilage between thyroid cartilage and inner perichondrium. c. 1955 Opheim transplanted thyroid cartilage medial to inner perichondrium - often required tracheotomy from edema. d. 1974 Isshiki described medialization of cord with piece of thyroid cartilage placed between inner perichondrium and thyroid cartilage. e. 1986 Koufman modified the Isshiki technique by using medical grade silastic implants custom fitted for each patient. 2. Surgical Medialization of Vocal Cord a. Indications: unilateral vocal cord paralysis with a wide glottic chink, patients who have failed teflon injection. b. Technique: Under local anesthesia with mild sedation with the larynx visualized (fiberoptic laryngoscope). (1) Skin incision is made over mid thyroid ala (2) Strap muscles retracted to expose thyroid ala (3) Elevation of outer perichondrium in an interiorly based rectangular flap. (4) Transillumination by nasopharyngoscope (5) Careful placement of window in the thyroid cartilage. (6) Subperichondrial elevation (tunnel technique) shifts the endolaryngeal structures medially. While the patient phonates, the best fit is achieved using preformed sialastic or custom tailored cartilage implant. The endolarynx is visualized using the fiberoptic scope. (7) Securing the implant to either strap muscles, perichondrium or thyroid cartilage. c. Advantages: Excellent results reported by Maves regardless of large glottic defects. The technique allows for adjustment. It is reversible. The vocal fold vibratory wave not altered. Little tissue reaction to silastic or cartilage. d. Disadvantages: Requires surgery, extrusion, migration, or resorption can occur. Does not allow the vocal fold to tense, thus diplophonia can still occur. e. Modifications: mainly involve customizing the implant . 3. Framework surgery that alters vocal cord tension a. Pioneered by Tucker b. General Idea: medialization techniques do not alter vocal cord tension. Selected voice disorders felt to be due to aberrant vocal cord tension. (1) the aged voice with flaccid cords (2) the androphonic voice of some women (3) the effeminate voice of some men (4) trans-sexual (5) ?spastic dysphonia c. Alteration of the antero-posterior diameter of larynx with alteration of the vocal cord tension is accomplished by surgery on the thyroid cartilage near the anterior commissure. d. Technique for Lengthening: (1) Horizontal skin incision mid-point of the thyroid cartilage straddling the midline. (2) superior and inferior flaps developed, strap muscles are retracted laterally. (3) Vertical cuts made 5mm on either side of midline through outer perichondrium and cartilage. The inner perichondrium is left intact. (4) The inner perichondrium is elevated 1 cm on the thyroid ala. (5) Pockets are created above and below the anterior commissure in the external perichondrium. (6) Tantalum sheeting is made into a retainer and custom formed for each larynx. These are placed medial to the thyroid cartilage above and below the anterior commissure. They effect a lengthening by wedging the mid-segment of the thyroid cartilage anteriorly, and act like shims. (7) The ends are placed in the pocket made between cartilage and external perichondrium. e. Technique for Shortening: (1) Described by Tucker 1989. (2) Indications: adductor spasmodic dysphonia due to excessive tension on the vocal cords. (3) Technique similar to that of the advancement procedure except that the central portion of the thyroid cartilage (containing Broyles' ligament) is retrused and held in place by permanent nylon sutures. (4) Report that 9/16 had good result with no spasm for 7 months to 2 years. 6/16 had return of spasms within three weeks post- op. VII. Laryngeal Reinnervation Techniques A. Nerve Transfer Techniques 1. Crumley (1986,1988) reports good results with ansa hypoglossi transfer in patients with unilateral vocal cord paralysis and mobile arytenoids. 2. Recurrent Laryngeal Nerve is anastomosed to the ansa hypoglossi as is enters the sternothyroid muscle using 10.0 monofilament suture and magnification. 3. Can be modified in the case of high vagal injuries to contralateral ansa anastomosed to the superior laryngeal nerve on the paralyzed side. This has given refinement in pitch control and raised the Fo. B. Nerve-Muscle Pedicle Techniques 1. Popularized by Tucker, can be used for either unilateral or bilateral vocal cord paralysis. 2. Unilateral paralysis is treated by implanting a nerve muscle pedicle created from the omohyoid and the ansa hypoglossi innervating it. 3. The nerve-muscle pedicle is about 2-3 mm cubed and is placed in a window in the inferior third of the thyroid cartilage. 4. The muscle implanted is the lateral thyroarytenoideus, a major adductor. 5. Results may take up to four months, at least 10% failure rate reported by Tucker. 6. Bilateral paralysis is treated by implanting an nerve-muscle pedicle from the omohyoid into the posterior cricoarytenoid. The pedicle is harvested and the larynx rotated laterally. The inferior constrictors are separated and the pyriform sinus is retracted superiorly. The cricoarytenoid is encountered, fibers split and the pedicle implanted. 7. Newer techniques Maniglia (1989) use the superior laryngeal motor branch to the cricothyroid muscle in a pedicle graft to the posterior cricoarytenoid. This is felt to be superior because of the phasic contractions during respiration of the laryngeal muscles. VIII. New Horizons in Voice Research A. Establishment of a Voice Disorders Laboratory 1. Two new pieces of equipment make possible objective evalualtion of voice. The significan t advance is the abiltiy to assess the characteristics of phonatory function at the level both of vocal fold vibrations and the resulting acoustic signal. a. Photoglotography - measures the light trasmission between the vocal cords (glottic chink) during phonation. b. Electroglotography provides measurements of the changes in electrical impedance across the larynx during vocal fold opening and closing. The dynamic impedance between the two skin electrodes that changes as the vocal folds spread apart and the approximate each other is recorded by EGG. 2. PGG and EGG are complimentary, one describes opening, the other closing activity. From these cyclic events, wave forms are generated and these can be subjected to analysis. 3. Both normal and disease states have been studied. B. How a Voice Lab may be used: 1. Case 1. 67 year old man with heavy voice and progressive fatigue and hoarseness. Voice became breathy as the day progressed. Indirect laryngoscopy by several experienced otolaryngologists was normal. Videolaryngoscopy was normal. PGG and EGG signals showed ill-defined baseline when closed and asymmetry of opening phase and from this a diagnosis of Parkinson's disease made. 2. 64 year old singer referred for spastic dysphonia. Patient noted gradual onset of difficulty with pitch and intensity. Examination by telescope showed hyperadduction of the vocal folds. EGG demonstrated rhythmic contractions of the hypopharynx at 2 Hz. Myoclonus of the vagal nerve structures diagnosed, no supranuclear pathology identifed. C. Useful measurements may include the open quotient which represents the time that the vocal folds are open during the glottic cycle. The speed quotient is the time the are opening divided by the time they are closing. -----------------------------------END------------------------------------------