Anatomy and Physiology

The anatomy most relevant to the benign vocal fold mucosal disorders is the microarchitecture of the vocal folds, as seen on whole-organ coronal sections in a study of cancer growth patterns^3,4 and in the work of Hirano.⁵ Medially to laterally, the membranous vocal fold is made up of squamous epithelium, Reinke’s potential space (superficial layer of the lamina propria), the vocal ligament (elastin and collagen fibers), and the thyroarytenoid muscle. Perichondrium and thyroid cartilage provide the lateral boundary of the vocal fold (Fig. 62-1).

Figure 62-1. Cross section of the vocal fold.

The vocal folds move as a whole between abducted and adducted positions for breathing and phonation, respectively. The mucosa (epithelium and superficial layer of the lamina propria [Reinke’s potential space]), which covers the vocal folds, is the chief oscillator during phonation (continuous adduction during expiratory flow of pulmonary air); thus, one might speak of vocal fold mucosal vibration rather than vocal fold vibration. In a canine study that supports this idea, Saito and associates⁶ placed metal pellets at varying depths into the vocal fold (e.g., epithelially, subepithelially, intramuscularly) and used radiographic stroboscopy to trace their coronal plane trajectories during vibration. Pellet trajectories of the mucosa were far wider than those of the ligament or the muscle. Thus, primarily the vocal fold mucosa oscillates to produce sound.

’The work of Hirano⁷ provides an explanation for these observations. Hirano described the vocal fold muscle as the body of the fold, the epithelium and superficial layer of the lamina propria (Reinke’s potential space) as the cover, and the intermediate layers of collagenous and elastic tissue (vocal ligament) as the transitional zone (see Fig. 62-1). Because of the different physiologic stiffness characteristics of these layers, they are somewhat decoupled mechanically from each other during phonation. Decoupling is graphically illustrated in Figure 62-2 (mucosa being stretched). This decoupling allows the mucosa to oscillate with some freedom from the ligament and muscle. An analogy can be made to the relative freedom from the paddle experienced by the red rubber ball and elastic band in a child’s paddleball toy. During phonation, pulmonary air power supplied to adducted vocal folds is transduced into acoustic power. To accomplish this, pulmonary air is passed between appropriately adducted vocal folds. At this point, the vocal fold mucosa vibrates passively according to the length, tension, and edge configuration determined by the intrinsic muscles and elastic recoil forces of the vocal fold tissues. Figure 62-3 shows the maximum open and closed phases of one vibratory cycle, as seen during laryngeal videostroboscopy. Further details concerning the mucosa’s vibratory behavior can be found in the works of Baer⁸ and Hirano⁵ and in Chapter 57.

Figure 62-2. Gentle medial retraction shows the relative decoupling of the mucosa from the underlying, nondeformed vocal ligament.

Figure 62-3. The maximum open (A) and closed (B) phases of an apparent single vibratory cycle as seen during videostroboscopy. The moving part is primarily mucosa, with little participation of ligament or muscle.

Other important microanatomy includes glands in the supraglottic, saccular, and infraglottic areas, which produce secretions that bathe the vocal folds during vibration.

Evaluation of the Patient: General Principles

The necessary and sufficient elements for diagnosis and management of benign mucosal disorders are (1) a skillful history, (2) a perceptual assessment of vocal capabilities and limitations, particularly through elicitation of vocal tasks designed to detect mucosal disturbances, and (3) a high-quality laryngeal examination (often including laryngeal videostroboscopy). In addition, certain measures of phonatory function (aerodynamic, acoustic), although not crucial for diagnosis, may be of interest for study, documentation of the disorder’s physiologic effects, and assessment of improvement after treatment.

Office Examination of the Larynx

The laryngeal mirror should provide three-dimensional viewing and good color resolution but, in practice, offers poor visualization in many cases. In other cases, visualization is good, but only during phonation, because the view is obstructed by the epiglottis during respiration. In addition, no permanent image of the larynx results from this examination technique. Because the physician must therefore remember the lesion or document it with a simple sketch, precise critique of the effectiveness of the therapy chosen may not be possible. Rigid and also flexible laryngeal scopes often allow a clearer view, particularly during respiration. When used with the naked eye, however, they have similar disadvantages to those of the mirror. The fiberoptic nasolaryngoscope or a newer “chip-tip” video-endoscope is especially important in a patient who is difficult to examine because of unusual anatomy or an exceptional gag reflex. Even with these technologies, however, it is possible to overlook subtle-to-small mucosal changes unless the larynx is topically anesthetized to allow a close approach of the tip of the fiberscope to the vocal folds. With topical anesthesia, the vocal folds, subglottis, and trachea can be examined easily (Fig. 62-4).^12,13

Figure 62-4. Three of the most commonly used tools for viewing the larynx: a mirror, a 90-degree telescope, and a flexible fiberoptic nasolaryngoscope. A later addition, the distal chip endoscope, which looks nearly identical but has an internal video chip rather than optics, is supplanting the fiberoptic scope.

Strobe illumination added to any of these examining instruments allows mucosal vibratory dynamics to be evaluated in apparent slow motion (e.g., to understand mucosal scarring, to distinguish cysts from nodules). Adding a video camera and recording device (computer hard drive or tape) to the rigid or flexible scopes brings additional advantages; for example, a patient’s understanding and motivation are facilitated if he or she views the video documented examination. Also, such recordings enable other clinicians (otolaryngologists, speech pathologists, voice teachers) to participate more easily in assessment and management, serve as permanent records that document the result of voice therapy or surgery, and enhance teaching of residents.

General Management Options

Management of Acid Reflux Laryngopharyngitis

In a person with an incompetent lower esophageal sphincter or hiatal hernia, acid reflux into the pharynx and larynx during sleep can lead to chronic laryngopharyngitis. Such persons may or may not experience one or more of the following symptoms: exaggerated “morning mouth,” excessive phlegm, scratchy or dry throat irritation that is usually worse in the morning, habitual throat clearing, and huskiness or lowered pitch of the voice in the morning. The larynx may show characteristic erythema of the arytenoid mucosa, interarytenoid pachyderma, or contact ulcers; laryngeal findings may, however, be subtle (Fig. 62-5).

Figure 62-5. Chronic laryngitis in a patient with severe acid reflux, a history of smoking, and excessive voice use. A, Note the interarytenoid pachyderma (arrows) and loss of normal color differential between the true folds and supraglottic mucosa. Broad-based convexity of the true vocal fold margins suggests diffuse submucosal edema. B, Appearance 3 weeks after institution of antireflux measures. Note the resolution of the interarytenoid pachyderma.

Basic management of this condition consists of avoiding caffeine, alcohol, and spicy foods; eating the last meal of the day (preferably a light one) no fewer than 3 hours before retiring; using bed blocks to place the bed on a mild head-to-foot slant; and taking an antacid at bedtime, an H₂ blocker 2 or 3 hours before bed, or a proton pump inhibitor 30 to 60 minutes before dinner.

Voice Therapy

A course of therapy by a voice-qualified speech pathologist is frequently appropriate in patients with benign vocal fold mucosal disorders, given the common relationship of such disorders with vocal overuse, abuse, or misuse. Vocal nodules in particular are expected to resolve, regress, or at least stabilize under a regimen of improved voice hygiene and optimized voice production. In some cases, however, success is defined as having achieved a more consistent voice, without the exacerbations of hoarseness and even aphonia, even if that now-more-reliable voice remains somewhat husky. In other cases, success may require resolution of all upper voice limitations. If surgery becomes an option because the mucosal disorder has not resolved completely and the patient regards residual symptoms and vocal limitations as unacceptable, voice therapy will have optimized the patient’s surgical candidacy, by educating him or her additionally about the surgical process, and decreased the risk of postoperative recurrence.

During evaluation, the speech pathologist gathers information on behavior that may adversely affect the voice and establishes a program to eliminate injurious behavior. Voice-qualified speech pathologists also model and elicit a battery of spoken and sung vocal tasks to make plain to themselves and patient the type and degree of impairment from the lesion. They also assess the skill and appropriateness of voice production for both speaking and singing. Depending on the results of this second part of the evaluation, the speech pathologist may help the patient optimize the intensity, average pitch, registration, resonance characteristics, overall quality, general and vocal tract posture, and respiratory support for voice production. For singers, the singing teacher plays an invaluable role in this process, particularly with respect to singing voice production.

Finally, in this technologic era, voice clinicians increasingly document various aspects of vocal tract output, using acoustic analysis, spirometric measures to test respiratory adequacy, frequency and loudness measures, translaryngeal airflow rates, and other measures under various conditions. Speech pathologists may use this equipment for biofeedback (e.g., using a visual electronic frequency readout to modify average pitch for speech in a tone-deaf patient). For obligate false vocal fold phonation and intractable psychogenic disorders of voice production with visible vocal fold posture abnormalities, therapy room videoendoscopy can also be converted into an effective biofeedback tool (Fig. 62-6).^11,16

Figure 62-6. A patient learning to modify laryngeal posture by use of laryngeal image biofeedback. With a telescope rather than a fiberscope, pure vocal fold behavior is retrained initially (without speech gestures). Clearer optics and less mobility of the epiglottis permit a clearer and more stable view.

Surgery

Some lesions are known at diagnosis to be irreversible other than via surgery. Aside from these exceptions, vocal fold microsurgery should follow an appropriate trial of voice therapy. Patients are typically reexamined (vocal capability battery and videostroboscopy) at 16-week intervals after diagnosis. When a compliant patient does not improve after two or more successive examinations and remains unhappy with the voice’s capabilities, surgery may be considered. Good surgical results are directly related to diagnostic accuracy, surgical judgment and precision, and the patient’s compliance with proper voice care.

Although specific techniques vary for each disorder, the basic requirements for successful laryngeal microsurgery for all benign vocal fold mucosal disorders are the same. An understanding of vocal fold microarchitecture and vibratory dynamics (see earlier discussion) is a prerequisite, and preoperative and postoperative videostroboscopic evaluation is necessary so that the patient and surgeon can see the results together.

The first principle of surgery is that microlaryngoscopy (not direct laryngoscopy with the unaided eye) and extreme technical precision are required to minimally disturb mucosa. Because the disorder is benign and confined to the mucosa, including Reinke’s potential space, the cancer concept of surgical margins does not apply. Every case should be approached with the awareness that overly aggressive or imprecise surgery of the vocal fold mucosa can have disastrous results caused by scarring of regenerated or surgically manipulated mucosa to the underlying vocal ligament.

A set of laryngoscopes, microlaryngeal forceps, scissors, dissectors, and knives should be on hand. In the face of the plethora of instruments currently available, the comment by Kleinsasser² that a relatively simple set suffices the experienced surgeon remains true (Fig. 62-7)!

Figure 62-7. A, The viewing ends (left to right) of the Holinger hourglass, Jako-Cherry, Bouchayer, and Dedo laryngoscopes. B, The distal ends of these laryngoscopes (same order). The Bouchayer scope (arrow) is most useful for microsurgery. C, From left, The up-cup forceps, smaller biting forceps, Bouchayer microring forceps, curved scissors, and curved alligator forceps.

The carbon dioxide laser has become an important part of the surgeon’s armamentarium, and many have discussed its application to benign laryngeal disorders. Tissue effects of the laser depend on spot size and focus, wattage, duration of beam activation, waveform mode (pulsed vs. continuous), and, perhaps most important, surgical precision. Cold microdissection may be safer than laser techniques, provided that the surgeon is equally proficient in both. Norris and Mullarky,¹⁷ comparing continuous-mode carbon dioxide laser with the cold scalpel for incising pig skin, reported that a short-term advantage resulted after laser incision with regard to the speed of reepithelialization; no long-term difference in healing was noted. However, although the fact was not noted in their report, these investigators’ histologic sections clearly showed a wider zone of tissue destruction beneath the epithelium with laser than with scalpel. Duncavage and Toohill¹⁸ compared healing response in dogs after traditional fold stripping and after carbon dioxide mucosal vaporization. They concluded that, until late in healing, more edema and giant-cell reactions to bits of charred debris, and greater subepithelial fibrosis occurred with the laser technique than with the cup forceps alone. Manipulation of wattage, focus, and mode of laser irradiation of tissues may decrease thermal injury, charring, and other adverse effects of the laser.

The preceding studies date from the early era of the carbon dioxide laser. The microspot carbon dioxide laser appears to diminish these disadvantages,^19,20 although a systematic comparison of functional results (including vocal capabilities and videostroboscopy) is not available to guide the surgeon in choosing between laser and microdissection methods. With a caseload approaching 1000 singers and double or triple that number of non-singers—for whom laser and non-laser methods have been used on an individualized basis—I believe that surgical technique and skill are preeminent over the specific tools used.

After surgery, vocal quality and capabilities should show good to excellent improvement; however, patients should be counseled preoperatively what the risk of worsening the voice is predicted to be: For nodules it may be appropriate to say, “This surgery typically restores the voice to ‘original equipment status,’ but there is a small risk that you will experience a large improvement but not to fully normal; and there is a remote, rare risk that your voice will be worse after surgery.” By contrast, one may say to the person with bilateral sulci in whom mucosa is thin, “I am expecting a modest improvement of your voice, but it will take many months to experience this improvement, and there is a quite significant chance your voice will be no better, and even possibly worse.” For the experienced surgeon who uses dissection, rather than microavulsion techniques, along with preoperative and postoperative videostroboscopy as his or her “teacher,” the question in the general case becomes not so much one of possibly making the voice worse, but rather, “Can I make this patient’s speaking and singing capabilities normal, and if not, how close can I come?” Cornut and Bouchayer’s²¹ experience operating on 101 singers and Bastian’s²² experience in the same population established a role for laryngeal microsurgery in restoring vocal capabilities and in abolishing or diminishing limitations.

Specific Benign Vocal Fold Mucosal Disorders

Vocal Nodules

The term nodules should be reserved for lesions of proven chronicity. Recent or acute mucosal swellings, which disappear quickly in response to simple voice rest and perhaps supportive medical management, are thus excluded when one is referring to nodules.

Epidemiology

Vocal nodules occur most commonly in boys and women. Such persons are almost always vocal overdoers (i.e., rating 6 or 7 on the 7-point talkativeness scale). Intrinsic talkativeness correlates more consistently than occupation, unless the occupation is extraordinarily demanding vocally (e.g., rock singer, stock trader). Comparatively, nodules develop frequently in children with cleft palates, presumably from their use of glottal stops to compensate for velopharyngeal incompetence.

Pathophysiology and Pathology

Only the anterior two thirds (membranous portion) of the vocal folds participates in vibration because the arytenoid cartilages lie within the posterior third of the glottic aperture. Vibration that is too forceful or prolonged causes localized vascular congestion with edema at the midportion of the membranous (vibratory) portion of the vocal folds, where shearing and collisional forces are greatest. Fluid accumulation in the submucosa from acute abuse or overuse results in submucosal swelling (sometimes unwisely called incipient or early nodules). Long-term voice abuse leads to some hyalinization of Reinke’s potential space and, in a subset of cases, some thickening of the overlying epithelium. This pathophysiologic sequence explains the easily reversible nature of most acute nonhemorrhagic swellings, in contrast to the slower, incomplete, or failed resolution of chronic vocal nodules. Whether acute edema or more chronic nodules, the change in mucosal mass, lessened ability to thin the free margin, and incomplete glottic closure caused by the nodules account for a constellation of vocal symptoms and limitations that is characteristic of mucosal swelling.^11,22

Diagnosis

History

A pediatric patient with vocal nodules is usually described by the parent as vocally exuberant. An adult patient, virtually always a woman who rates herself as a 6 or 7 on the talkativeness scale (discussed earlier), describes experiencing chronic hoarseness or repeated episodes of acute hoarseness. Sometimes the initial onset is associated with an upper respiratory infection or acute laryngitis, after which the hoarseness never clears completely, leading the patient to incorrectly attribute the voice problem to the infection and to neglect more relevant ongoing behavioral causes. Singers with chronic nodules are usually relatively unaware of speaking voice limitations unless the nodules are at least moderate in size. More sensitive symptoms of vocal nodules, including very small ones, are as follows:

• Loss of the ability to sing high notes softly

• Delayed phonatory onset, particularly with high, soft singing

• Increased breathiness (air escape), roughness, and harshness

• Reduced vocal endurance (“I get husky more easily than others.”)

• A sensation of increased effort for singing

• A need for longer warm-ups

• Day-to-day variability of vocal capabilities that is greater than expected for the singer’s level of vocal training

Vocal Capability Battery

In patients with moderate to large vocal nodules, the speaking voice is usually lower than expected, husky, breathy, or harsh. Patients with subtle to moderate swellings often have speaking voices that sound normal; the speaking voice is an insensitive indicator of mucosal disorders in comparison with the singing voice. In patients with subtle or small swellings (usually only singers present with small mucosal disturbances), vocal limitations (e.g., delayed phonatory onset with preceding momentary air escape, diplophonia, inability to sing softly at high frequencies) may become evident only when high-frequency, low-intensity vocal tasks for detecting swelling are elicited.^11a At high frequency, short-segment vibration may occur; in other words, the nodules stop vibrating and the short segments of mucosa anterior or posterior to them, or both, vibrate.

Many patients with nodules may have undergone indirect laryngoscopy and have been told that their vocal folds were normal or have been given a nonspecific diagnosis such as “laryngeal irritation.” Use of vocal tasks that detect swellings and videostroboscopy, when indicated (see Figs. 62-3 and 62-4), protect the laryngologist from missing the most subtle vocal fold swellings. The ability to diagnose tiny nodules is crucial, because failure to make such a diagnosis can have serious consequences for the professional voice user.

Laryngeal Examination

Nodules can vary in size, contour, symmetry, and color, depending on how long they have been present, the amount of recent voice use, and interindividual differences in mucosal response to voice abuse. Also, some variability exists in the correlation between size of nodules and their effect on vocal capabilities. Nodules do not occur unilaterally, although one may be larger than the other. It is important to distinguish between nodules and cysts, because management of these conditions differs. The correlation between nodule appearance and reversibility with voice therapy is imperfect. The larynx should be examined at high frequency (500-1000 Hz) to visualize subtle to small swellings, which can be poorly appreciated at lower frequencies.

Management

Medical

Good laryngeal lubrication should be ensured through general hydration. Allergy and reflux, when present, should be treated.

Behavioral

Vocal nodules arise from the vocal overdoer profile, so speech (voice) therapy plays a primary role initially. Typically, the nodules and their more obvious symptoms regress, particularly if the patient is not a singer. However, the most skilled behavioral (voice) therapy sometimes fails to achieve complete visual resolution of nodules that have been present for many months to years. Sensitive singing tasks that detect impairment (not the size of persistent swellings) are generally more helpful in the decision whether to consider their surgical removal.^11,22

Surgical

Surgical removal becomes an option when nodules of whatever size persist and the voice remains unacceptably impaired (from the patient’s perspective) after an adequate trial of therapy (generally a minimum of 3 months). Some writers prefer precise removal using microdissection techniques (Fig. 62-8). Vocal fold stripping has no place in the surgery of nodules. The proper duration of voice rest is controversial; some writers prefer a relatively short period. Typically, the patient is asked not to speak for 4 days, although sighing sounds begin 1 day after surgery. Beginning on the fourth day, the patient gradually progresses over 4 weeks to full voice use under a speech pathologist’s supervision. Early return to nonstressful voice use, as described in Table 62-1, seems to promote dynamic healing. The results of precision surgery are typically remarkably good, even in singers. Cornut and Bouchayer²¹ stated, in their study of approximately 160 singers treated with surgery, “As long as certain management principles are followed in a majority of cases, laryngeal microsurgery enables the singing voice to regain the whole of its functioning.”

Figure 62-8. The operative sequence in a professional musical theater actress who had been experiencing vocal symptoms and limitations compatible with fusiform vocal nodules for more than 2 years. A, The operative view after many months of conservative management. Not all fusiform swellings are reversible with conservative measures alone. B and C, A polypoid nodule is grasped superficially and tented medially with Bouchayer forceps. Scissors, which curve away from the vocal fold, are used for removal. The nodule is thus removed in a very superficial plane, thereby minimizing the risk of engendering scar between the remaining and regenerated mucosa and the underlying vocal ligament. D, The vocal fold appearance after excision. The patient experienced dramatic normalization of vocal capabilities, and there was no evidence of scarring on postoperative stroboscopic examination. The dilated capillaries may predispose to recurrent nodule formation and can be spot-coagulated with a micro-spot laser.

Table 62-1 General Guidelines for Initial Voice Use after Vocal Fold Microsurgery

Time After Surgery*	Talking†	Singing (for Singers)
Days 1 to 4	None	Gentle attempts at yawn or sigh for approximately 30 sec, 6-8 times per day‡
Week 2 (begins day 5)	3	Same exercise 5 min twice per day (after first postoperative exam)
Week 3	4	Same exercise 10 min twice per day§
Week 4	5	Same exercise 15 min twice per day§ (after second postoperative exam)
Week 5	4 or 5	Same exercise 20 min twice per day§
Weeks 6-8	4 or 5	Same exercise, up to 20 min three times per day|

* After fourth examination, return to performance should be considered.

† Based on a 7-point talkativeness scale, in which 1 = very untalkative, 4 = average, and 7 = extremely talkative.

‡ Accept what comes out, even if it is only air or is very hoarse.

§ With emphasis on ease, clarity, and agility, not voice building. The entire expected range should be practiced in each session, with gentle insistence on high notes that do not want to sound. In general, practice mostly a mezzo piano dynamic and only occasionally a mezzo forte.

| Same as preceding footnote, with the addition of gradually increasing the dynamic range and insistence.

Capillary Ectasia

Epidemiology

Capillary ectasia seems to happen most often with vocal overdoers (Figs. 62-9 to 62-11). Because of the female preponderance of this disorder, some writers have speculated about an estrogen effect.

Figure 62-9. Vocal nodules with associated capillary ectasia. A, Superficial ectasia is seen (black arrows); the white arrow indicates deeper ectasia seen within left-sided nodule. B, The left vocal fold margin is rolled up onto the superior surface of the fold so that ectasia within the nodule can be seen more clearly (arrow), particularly the knuckle variant. C, Nodules have been removed (see Fig. 62-8), but spot-coagulation of dilated capillaries is present at approximately 2-mm intervals (arrows).

Figure 62-10. Operative view of a hemorrhagic polyp on the right true vocal fold of 14 months’ duration. Note the capillary ectasia.

Figure 62-11. A, A large right epidermoid inclusion cyst with a characteristic dilated capillary. Note the large left nodule. B, An epidermoid inclusion cyst in another patient is delivered through a cordotomy incision.

Pathophysiology and Pathology

Repeated vibratory microtrauma can lead to capillary angiogenesis. In a circular fashion, abnormally dilated capillaries seem to increase the mucosa’s vulnerability to further vibratory trauma. In particular, mucosal swelling, when present with capillary ectasia, appears to be larger on the side with greater ectasia. It seems that capillary ectasia predisposes to one or more of the following: increased vulnerability to mucosal swelling (reduced vocal endurance), a small incidence of vocal fold hemorrhage, and hemorrhagic polyp formation.

Diagnosis

History

Capillary ectasia is diagnosed most often in female singers who complain that they become a little hoarse after relatively short periods of singing (reduced vocal/mucosal endurance). When this complaint is associated with mucosal swelling, additional symptoms reminiscent of nodules (e.g., delayed phonatory onset, loss of high soft singing, increased effort) may also be noted. The occasional singer with capillary ectasia may have experienced one or more episodes of acute vocal fold hemorrhage, which may precipitate the patient’s first visit; capillary ectasia may be discerned only after the bruising has resolved.

Vocal Capability Battery

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1. Voice Evaluation
2. Central Neural Auditory Prosthesis
3. Nasal Fractures
4. Total Laryngectomy and Laryngopharyngectomy

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