THE EVOLUTION OF THE ASSESSMENT AND TREATMENT OF PARALYTIC DYSPHONIA

VOICE DISORDERS AND PHONOSURGERY I

0030-6665/00 515.00+ .OO

THE EVOLUTION OF THE ASSESSMENT AND TREATMENT OF PARALYTIC DYSPHONIA Steven M. Zeitels, MD

Vocal fold paralysis has been an omnipresent disorder throughout the annals of laryngologic history since the origin of the specialty in 1858. Infectious aerodigestive tract diseases dominated 19th century literature, cancer was the primary focus of the 20th Century investigations,and vocal fold paralysis has been the laryngologist's nemesis through both centuries. The attendant complexity of laryngoscopic presentation, physiologic dysfunction, and surgical rehabilitation has led to a rich heritage of scientific investigationsthat can be traced through the past 140years. The following historical summary provides the reader with a working knowledge of past experiences that connects to current initiatives and portends future progress. PHYSIOLOGIC EXPLANATIONS OF VOCAL FOLD PARALYSIS

Garcia's presentation of mirror laryngoscopy(1855)was entitled "Observations on the Human Voice."" In that work, he provided an early explanation of the relationship between the aerodynamic valvular competency of the glottis and the resulting acoustic vocal outcome. Although there were a number of physicians who described mirror laryngoscopy in the first half of the 19th Century, Garcia, in a unique fashion, related his observations to the physiologic basis of laryngeal sound production.

From the Department of Otology and Laryngology, Harvard Medical School; and the Division of Laryngology,Massachusetts Eye and Ear Infirmary, Boston, Massachusetts OTOLARYNGOLOGICCLINICS OF NORTH AMERICA VOLUME 33 * NUMBER 4 * AUGUST 2000

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ClerF3believed that this was the primary catalyst for the development of Furthermore, an laryngology (2 years later) by CzermakZ0and inextricable linkage between laryngology and the study of human voice production ensued. Vocal fold paralysis was observed and described by 1859; T ~ r c in k~ ~ later, he demonstrated the associated laryngoscopic image in his atlas of laryngoscopic pathology.63Knight (Fig. 1)'the first Professor of Laryngology at Harvard Medical School, was the first individual in the United States to describe laryngoscopic findings associated with vocal fold paralysis.45Elsberg (Fig. 2) referred to the aerodynamic insufficiency caused by the malpositioned paralyzed vocal fold as "phonatory leakage of air."= GerhardP (1863) provided early explanations for the varied visual presentations of laryngeal paralysis based on site of lesion analyses and later introduced the term cuduveric position. Schech%provided the foun-

Figure 1. Frederick Irving Knight (1841-1 909). Third President of the American Laryngological Association.

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Figure 2. Louis Elsberg (1837-1885). First President of the American LaryngologicalAssociation.

dation for the early theories delineating innervation of the laryngeal musculature. Because the concept of synkinesis17was not understood, the early textbooks of l a r y n g o l ~ g recorded p ~ ~ ~ ~complex explanations for the varied positions of paralyzed vocal folds that were observed with mirror laryngoscopy.The spectrum of observed arytenoid positions was ascribed to denervation of varied combinations of one or more intrinsic laryngeal muscles.u About the same time (-1880), RosenbachS7and SemonS9postulated that the abductor fibers of the recurrent laryngeal nerve were more sensitive to injury, and this differential susceptibility resulted in the variable resting positions of the arytenoid that were observed. In contrast to Rosenbach and Semon, Jelenffybelieved that the clinical resting position of the arytenoid was the result of contraction of laryngeal muscles from irritative stimuli of peripheral or central 0rigin.3~ Kra~se50,~~ supported Jelenffy’s position and contested Semon’s theories after per-

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forming one of the earliest mammalian experiments in neurolaryngology. He based his conclusions on physiologic experiments and clinical observation. Jelenffy then performed his own experiments3*to substantiatethe contraction theory. Jelenffy's and Krause's 19th Century observations regarding the paramedian and median positions of the paralyzed arytenoid are explained today by synkinesis. Soon thereafter, Jelenffy40 provided elegant analyses of the agonistantagonist function of the intrinsic laryngeal musculature and its influence on the loosely encapsulated cricoarytenoid joint. He also described the frequently encountered anteromedial displacement of the corniculate region of the arytenoid, which was typically accompanied by inferolateral displacement of the vocal process. Solis-Cohen61and Casselberry12made similar observationsto those of Jelenffyregarding arytenoid position. Furthermore, Solis-Cohen described "spasmodic contractions" and Casselberry described "twitching" of the arytenoid that is reminiscent of unfavorable synkinesis, which has been elucidated by C r ~ m l e y . ~ ~ , ' ~ A dispute developed regarding the validity of the divergent theories espoused by the different investigators: Rosenbach and Semon versus Jelenffy and Krause. The most critical aspect of this intellectual controversy, however, was that it served as the catalyst for the origin of experimental neurolaryngology. Knight believed firmly that the controversies and mysteries of the clinical and physiologic observations about vocal fold paralysis could only be resolved by means of scientific experimentation.Therefore, he inspired his younger colleague Hoope132,e4 to engage the Harvard physiology laboratory to embark on a series of investigations. A plethora of mammalian experiments was conducted to model the contractile function of the laryngeal musculature (Fig. 3). H o ~ p e r ~ - ~ l , ~ was a leader in this movement and presented his work (1883-1888) at the early meetings of the American Laryngological Association (ALA). His brilliant contributions were decades ahead of their time. Unfortunately, Hooper's career was cut short as he succumbed to tongue cancer at the age of 43. Solis-Cohen, the Nestor of American Laryngology (through its first 50 years) discussed the heuristic significance of Hooper's seminal investigationsin experimental neurolaryngology at the 7th meeting of the ALA and referred to it as "historical."33Donaldson21,22 was also a sigruficant contributor to the infant field of experimental neurolaryngology. Ironically, these investigators' research provided support of the Rosenbach-Semon theory despite the fact that Jelenffy's and Krause's theories are closer to what is believed today. Synkinesis is a type of neural-stimulated, irregularly organized contraction of musculature. In time, the W a g n e r - G r ~ s s m a n ~theory Q~~,~ (1890s) ~ became another accepted explanation of the observed variability of arytenoid and vocal fold position. This theory stated that the position of the paralyzed vocal fold was predicated on the contractile activity of the cricothyroid muscle. Grossman performed systematic neurotomies of the superior and recurrent laryngeal nerves in mammals to develop his philosophy. King and Gregg42 and Clerf14outlined the mid-20th-century perspective regarding the variable resting position of the paralyzed arytenoid. They stated that

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Figure 3. Parody displaying canines escaping from the Harvard Medical School physiology laboratory with electrical stimulation wires attached to their laryngeal nerves. The dogs are chasing Dr. Hooper (portrayed as an animated head mirror) for subjecting them to his neurolaryngologic experiments. (Courtesy of the Francis Countway Library, Harvard Medical School, Boston, MA.)

the critical variables were: (1)contractile activity of the cricothyroid muscle; (2) postatrophy fibrosis and contracture of the intrinsic laryngeal muscles; and (3) the variable anatomy of the recurrent laryngeal nerve, which could lead to extralaryngeal arborization. This last factor became a primary explanation for the variable laryngoscopic presentation of postthyroidectomy paralyses. At present, the observed variable resting position of the arytenoid and in turn, the musculomembranous vocal fold is believed to be second(2) unpredictable reinnervation and ary to: (1)residual innervati~n;'~J~,~O and (3) atrophy (described in 18725,41)and fibrosis of denervated These factors also determine the final position, contour, length, mass, and viscoelasticity of the vocal fold. TREATMENT OF UNILATERAL VOCAL FOLD PARALYSIS

From the origin of laryngology in the mid-1800s to the latter part of that century, clinical and academic efforts regarding vocal fold paralysis focused on the underlying diagnostic etiology of the paralysis with the hope that there was a treatable d i ~ o r d e r . ~ , ~ of the introducAs, ~a ~result tion of electricity, the sole laryngeal treatment for the neural deficit in the

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Figure 4. Various 19th Century laryngologic instruments including Mackenzie’s probe (third from top) to apply electrical stimulation. (Courtesy of the Massachusetts Eye and Ear Infirmary, Boston, MA.)

Figure 5. Chevalier Jackson (1865-1958). (Courtesy of the Massachusetts Eye and Ear Infirmary. Boston, MA.)

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19th century was mirror-guided application of electric current (faradism and galvanism)?,53,60 M a ~ k e n z iintroduced e~~ this concept by devising specially designed probes to stimulate the arytenoid (Fig. 4). The rationale for this approach was to catalyze neurogenic recovery and to prevent atrophy of the laryngeal musculature in the event that the paralysis was reversible. Remarkably, the application of galvanic current by means of direct laryngoscopy was the primary local laryngeal treatment described by the Jacksons (Fig. 5) in their 1937 textbook, T h e Larynx and its Disease~.’’~~ Zealer et alR resurrected this concept in 1977, and this has developed into current initiatives of electrical pacing of paralyzed laryngeal m~sculature.~~ During the 20th Century, a variety of surgical procedures were designed to rehabilitate the paralyzed vocal fold by enhancing aerodynamic valvular competency of the glottis. This was done by optimizing one or more of the following properties of the vocal fold: position, size, contour, length, mass, and viscoelasticity. Successful phonosurgical treatment of paralytic dysphonia commenced with the injection of substances into the paraglottic space to medialize the paralyzed vocal fold. BruningsloJ1introduced injection techniques (Fig. 6 and 7) for unilateral vocal fold paralysis in 1911. Through his self-maintaining external-

Figure 6. Wilhelm Brunings. (From Brunings W: Direct Laryngoscopy, Bronchoscopy, and Esophagoscopy. London, Bailliere, Tindall, and Cox, 1912, p 114.)

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Figure 7. Brunings’ latyngoscope and paraffin injection needle. (From Brunings W: Direct Latyngoscopy, Bronchoscopy, and Esophagoscopy. London, Bailliere, Tindall, and Cox, 1912, p 116.)

counter-pressure direct-laryngoscope,9he placed intracordal paraffin by means of a novel injecting device that he designed. It was not until the 1950s to 1960s, however, when A m ~ l d ~championed , * ~ ~ ~ injection medialization, that it became the mainstay of phonosurgical treatment for paralytic dysphonia. Medialization of the vocal fold edge by means of neural reinnervation (phrenic or descending hypoglossus to recurrent laryngeal nerve) was introduced by Ballance3s4in 1924 and advanced in recent years by TuckeP,” and C r ~ m l e y ~Although ~ J ~ J ~ this approach has not become mainstream, it has significant promise for the future. The seminal investigation describing medialization of the laryngeal framework for treating paralytic dysphonia was introduced by PayP (Fig. 8 ) in 1915. In that approach, he designed an anteriorly based rectangular

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Figure 8. Erwin Payr. (From von Leden H:The history of phonosurgery. ln Ford CN, Bless DM (eds): Phonosurgery. New York, Raven Press, 1991, pp 3-24; with permission.)

cartilaginous flap (Fig. 9) that was depressed to medialize the musculomembranous vocal fold. Although this technique was explored further by Meurman,%," Opheim,68Waltner,@Miehlke,""and Swashhag in the middle part of the 20th century, framework medialization did not become mainstream until the recent past. Isshiki'sJ",%(Fig. 10) landmark investigations in the 1970s established a systematic design and organization of laryngeal framework surgery?5 These reports were catalysts for the current paradigmatic shift from injection techniques to laryngoplasticphonosurgery for the treatment of vocal fold paralysis. This consisted of medialization laryngoplasty (thyroplasty type I)%and arytenoid adduction.% A critical aspect of these contributions is that Isshiki taught surgeons to perform these procedures with local anesthesia with sedation, thereby facilitating intraoperative conversation between the patient and surgeon. This allowed for dramatically improved vocal results.

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Figure 9. Diagram from Payr’s original reporP describing medializationlaryngoplasty

Figure 10. Nobuhiko Isshiki.

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In the United States, K ~ u f r n a nled ~ ~ the , ~ ~drive towards adopting Isshiki’s procedures to become the dominant treatment modality for paralytic dysphonia. He not o d y made numerous modifications, but also created the term luyrzguplustic phurzusurgery.* Recently, Zeitels et a174introduced the adduction arytenopexy procedure, which is the first formal modification of Isshiki‘s arytenoid adduction operation. They noted that with this static reconstruction, patients had unperturbated conversational voices with typically less than 1.5 octaves of dynamic pitch variation. Therefore, a cricothyroid subluxation procedure75was designed to increase length and tension of the denervated vocal fold, which has dramatically improved maximal-range vocal tasks. This procedure is unlike all prior static procedures, which were devised primarily to reposition the paralyzed vocal edge in a more optimal position to facilitate entrained oscillation with the innervated vocal fold. SUMMARY

The study and treatment of vocal fold paralysis and paralytic dysphonia has been an enduring clinical problem in laryngology and continues today. In the 19th Century, direct treatment of the larynx was confined to electrical stimulation. Static reconstruction has been the mainstay of treatment in the 20th Century. This was primarily injection medialization until the last 2 decades when it became laryngeal framework restructuring. Ironically, dynamic reconstruction of vocal fold paralysis will probably evolve as the dominant treatment modality in the 21st Century, reminiscent of the initiatives of our 19th Century forefathers.

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