Plain roentgenography in the evaluation of unilateral vocal cord mobility

Am J Otolaryagol 4;92- lee, 1983

Plain Roentgenography in the Evaluation of Unilateral Vocal Cord Mobility ZIADE. DEEB, M.D. Despite the availability of many methods for the structural and functional evaluation of the larynx, this study suggests that plain roentgenographic techniques are simple and effective means of providing diagnostic and prognostic data useful in the management of hemilaryngeal dysfunction. Lateral soft tissue and anteroposterior views of the neck can demonstrate unilateral vocal cord dysfunction within a few hours after onset. Complete recovery of vocal cord function is most likely to occur when hemilaryngeal dysfunction is not associated with the appearance of a distended ventricle on the lateral soft tissue roentgenogram of the neck. Conversely, when the distended ventricle assumes a delta or Y configuration, it is unlikely that the hemilarynx will resume its normal mobility. Laryngeal immobility lasting more than six months is usually irreversible. (Key words: Plain roentgenography; Vocal cord dysfunction; Laryngeal ventricle.)

Vocal cord d y s f u n c t i o n is becoming an increasingly c o m m o n clinical p h e n o m e n o n . ' At times, the otolaryngologist is required to determine the status of laryngeal furmtion of patients in w h o m indirect l a r y n g o s c o p y is either uncomfortable or technically impossible because of limited neck mobility d u e to cervical spine injuries or neck surgery. Under such conditions, the examiner may have to resort to a variety of diagnostic aids t h a t m a y be time-consuming, complex, and expensive. The problem of vocal cord paralysis has been studied extensively. A m o n g the proposed methods to evaluate laryngeal mobility are fluoroscopy a n d cineradiography, tomography, laryngography, stroboscopy, electromyography, xerographic zonography, and high-speed photography. 2-6 A l t h o u g h c o m p u t e r i z e d tomography has been mentioned, there is no report yet of its successful use to evaluate laryngeal mobility2 T h o u g h all these m e t h o d s may be accurate, most are not universally available. There is a lack of medical literature dealing with the subject of roentgenographic evaluation of vocal cord function. Published studies have

been almost exclusively limited to the roles of tomography and laryngography. The value of conventional r o e n t g e n o g r a p h i c t e c h n i q u e s is usually dismissed by most authors. 7,~ It has been m y impression that a relationship exists between long-standing vocal cord paralysis and the presence of an enlarged ventricular air s h a d o w in the lateral and anteroposterior x-ray views of the neck. These changes in the image of the ventricle and other structures of the l a r y n x were o b s e r v e d n o t o n l y in c a s e s of hemilaryngeal paralysis of many years' duration, but also on radiographs of patients that w e r e obtained only hours after they had i n c u r r e d laryngeal impairment. To determine the accuracy of these impressions and their reliability, the following clinical study was undertaken with two major aims in mind: To survey the radiologic signs of unilateral vocal cord dysfunction. 2. To determine whether specific image patterns in the lateral a n d a n t e r o p o s t e r i o r soft tissue views of the neck result consistently from vocal cord d y s f u n c t i o n a n d , therefore, may be used to d o c u m e n t its presence and predict the prognosis for its resolution. 1,

From the Department of Otolaryngology,WashingtonHospital Center/Georgetown University Affiliated Hospitals, Washington, D.C. Received June 9, 1982; accepted for publication November 15, 1982. Presented as a thesis to the American Laryngological, Rhinolagical, and OtologicaI Society, Inc. Address correspondence and reprint requests to Dr. Deeb: Department of Otolaryngology,WashingtonHospital Center, 110 Irving Street, N.W., Washington, D.C. 20010.

Throughout this article, the term " d y s f u n c tion" is used to describe the functional status of the impaired larynx before it has been deter-

92

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Figure 1. Frontal tomograms of normal larynx.Left, right-angledsubglattic dome (arrow) during phonation. Right, effacement of laryngeal ventricle during quiet breathing. The apex of the pyriform sinus (arrowhead) is level with th~ vocal cords. mined to be irreversibly paralyzed following an observation period of at least six months. REVIEW OF C O N V E N T I O N A L TECHNIQUES AND SIGNS OF H E M I L A R Y N G E A L DYSFUNCTION

To interpret correctly the plain roentgenographic images of the larynx, it is instructive to have a k n o w l e d g e of the n o r m a l and the paralyzed bemilarynx as they appear in frontal t o m o g r a p h y (Figs. i and 2). Most reports :~'"~ agree that the cardinal roentgenographic signs of vocal cord paralysis are the following: 1. Thinning of the paralyzed vocal cord 2. Elevation of the paralyzed vocal cord 3. Elevation of the apex of the pyriform sinus on the paralyzed side 4. Blunting or flattening of the subglottic angle on the paralyzed side 5. Dilatation of the ventricle on the paralyzed side Actually, the only signs that can be detected r o u t i n e l y on conventional roentgenographic

views are blunting of the subglottic angle on the anteroposterior image of the neck, and dilatation of the ventricular air space on the lateral image, provided that both views are obtained using soft tissue exposure technique.

Anteroposterior (AP) View of the Neck with Soft Tissue Technique It is important to obtain this AP view both during quiet or suspended breathing and during the phanation of "~e" ar performance uf the Valsalva maneuver so that the mobility of the vocal cords can be demonstrated and the ventricular air space is accentuated. The dome-shaped appearance of the normal subglottic air column is a constant feature and must be sought in the AP view of the normal larynx (Fig. 3). Any change in the right-angled appearance at the dome should be considered a b n o r m a l Changes in the subglottic air shadow may be caused by inflammation, neoplasm, or neurogenic h e m i l a r y n g e a l

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ROENTGENOGRAPI-IY OF VOCAL CORD DYSFUNCTION

Figure 2. Frontal tomogram of larynx with unilateral paralysis. Left, during phonation there is an acute subglottic angle (arrow) on the normal right side, while on the left side there is an obtuse angle (arrowheadl, the pyriform apex is elevated, and the ventricle is dilated. Right, during quiet breathir~g the right side effaces normally, but the left maintains its previous appearance and position.

American JournaJ of Otoiaryngo]ogy 94

Figure 3. Anteroposterior roentgenogram during phonation (left) and during quiet breathing [right). Notice the symmetric subglottie dome (arrow).

DEEB

Figure 4 (above]. Anteroposterior roentgenogram of a patient with a right hemilaryngeal paralysis. Left, an phanation the left cord is adducted and has an acute subglottic angle while the right subglottic angle is obtuse [arrowhead), Right, on quiet breathing the right subglottic angle remains blunted (arrow). This view was adequate to confirm an initial impression of right hemilaryngeal dysfunction. Figure 5 (right). Lateral view of neck soft tissue. Notice ventrieular air in a normal larynx (arrow).

d y s f u n c t i o n (Fig. 4). If vocal cord i m m o b i l i t y is d e m o n s t r a t e d on the AP view, t o m o g r a p h y may not be needed.

Lateral View of Neck Soft Tissue To visualize the v e n t r i c u l a r air space o n this view, it must be o b t a i n e d with the patient's neck e x t e n d e d and d u r i n g the p h o n a t i o n of "-~e," or while the patient is p e r f o r m i n g the Valsalva man e u v e r (Fig. 5). T h e key to u n d e r s t a n d i n g the r o e n t g e n o graphic study of laryngeal d y s f u n c t i o n lies in the recognition of the difference between tonicity and atonicity of the structures s h a p i n g the three subdivisions or c o m p a r t m e n t s of the larynx. Thus, in the normal organ, both true vocal cords are at the same level and the two ventricles present a single horizontal air c o l u m n o n the lateral view of the neck. When the r e c u r r e n t laryngeal nerve is d a m a g e d on o n e side, the posterior cricoa r y t e n o i d m u s c l e loses it t o n i c c o n t r a c t i o n , freezing the v e n t r i c u l a r l i g a m e n t from its posterior anchor while leaving it firmly attached anteriorly to the thyroid lamina.

The degree of t o n i c i t y in the v e n t r i c u l a r ligament p r o b a b l y d e p e n d s on the s e v e r i t y of n e r v e d a m a g e , i.e., n e u r o p r a x i a or n e u r o t m e s i s . On physical e x a m i n a t i o n t h e r e is a p p a r e n t i m m o bility of the vocal cord in both situations and a c o r r e s p o n d i n g r o e n t g e n o g r a p h i c a p p e a r a n c e of an elevated or d i s t e n d e d v e n t r i c l e on the impaired side d e m o n s t r a t e d o n the lateral v i e w of neck soft tissue. This d i s s o c i a t i o n b e t w e e n the two v e n t r i c u | a r images m a y result in two different patterns on this lateral view. In one the ventricular air space is m a s s i v e l y d i l a t e d w i t h a s m o o t h regular o u t l i n e (Fig. 6), w h i l e in the o t h e r t h e d i l a t a t i o n a s s u m e s a Y - s h a p e d air shadow. According to B a c h m a n , ~ this triangular c o n f i g u r a t i o n of the v e n t r i c u l a r air s p a c e is p a t h o g n o m o n i c of v o c a l c o r d p a r a l y s i s . T h e v e n t r i c u l a r air space of t h e p a r a l y z e d h e m i l a r y n x m a y also f r e q u e n t l y a p p e a r t r i a n g u l a r (delta sign) with the apex of the triangle pointing superiorly (Fig. 7). MATERIALS AND METHODS One h u n d r e d lateral v i e w s of n e c k soft tissue in n o r m a l adults were s t u d i e d to d e t e r m i n e the

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ROENTGENOGRAPHY OF VOCAL CORD DYSFUNCTION

Figure 6. Lateralview of neck soft tissue. Left, dilated ventricular air shadow [arrow) typical of hemllaryngeal impairment of a reversible nature. Right, dilatation of the ventricle with delta pattern (arrowhead) in a patient with hemilaryngeal impairment of an irreversible nature.

m o s t c o m m o n p a t t e r n t h e v e n t r i c u l a r air s p a c e a s s u m e s . With o n l y m i n o r v a r i a t i o n s , t h e foll o w i n g c o n d i t i o n s w e r e u s e d in the soft t i s s u e t e c h n i q u e to o b t a i n t h e l a t e r a l a n d a n t e r o p o s t e r i o r views. To o b t a i n a l a t e r a l v i e w of t h e n e c k i n soft t i s s u e t e c h n i q u e , t h e c e n t r a l b e a m is a i m e d at the t h y r o i d n o t c h f r o m a d i s t a n c e of 180 cm. The p o w e r is 68 to 70 kV a n d 100 m A for 0.25 s e c o n d . To o b t a i n a n a n t e r o p o s t e r i o r v i e w of t h e n e c k i n soft t i s s u e t e c h n i q u e , the c e n t r a l b e a m is a i m e d at t h y r o i d n o t c h f r o m a d i s t a n c e of "100

cm. The p o w e r is 120 kV a n d 300 m A for 0.05 second. F r o m July "1975 t h r o u g h D e c e m b e r 1980, 48 adults with hemilaryngeal dysfunction not c a u s e d b y t u m o r s of the u p p e r a e r o d i g e s t i v e tract were s t u d i e d . A l l of t h e s e p a t i e n t s u n d e r went examinations of t h e n e c k u s i n g t h e above-mentioned techniques. Laryngeal polyt o m o g r a m s w e r e o b t a i n e d in all c a s e s to c o n f i r m the p l a i n r o e n t g e n o g r a p h i c f i n d i n g s . T h e i n t e r v a l s f r o m o n s e t of s y m p t o m s t o r a d i o logic evaluations ranged from several hours

TABLE 1.

Summary o f 48 Cases

Patients with Dilated Ventricle witheut Delta Sign

Americon Journol of Otoloryngology 96

Cause of Vocal Cord Dysfunction

Number of Patients

Intubation Thyroidectomy Parathyroidectomy Cervical spine fusion and larainectomy Cervical spine fracture Carotld endarterectomy Penetrating neck wounds Drug injection at neck Bulbar polio

18 11 3 4 1 5 3 2 1

Number

Number Recevered

Averago Rocovery "Pime (Months)

4 2 12

2

DEEB

I

\' Figure 7. P a t t e r n s of v e n t r i c u l a r air s e e n on lateral view of neck soft tissue, o, Normal; b, dilatatinn; a n d c, d i l a t a t i o n w i t h delta configuration.

(trauma patients) to 20 years (thyroidectomy patients). All conventional films were obtained on the day of the initial physical examination. The m i n i m u m follow-up period for any patient in this series was a year, and functional recovery was continued by both plain roentgenograms and polytomograms.

ity was confirmed by plain soft tissue AP views and frontal tomograms of the neck. All of the patients in this subgroup recovered full mobility of the i m p a i r e d cord w i t h i n t h r e e m o n t h s (Fig. 8). All 11 patients who had undergone thyroide c t o m y had e v i d e n c e of a d i l a t e d ventricle with a positive delta sign. After a m i n i m u m of one year of follow-up, none of the patients in this group showed evidence of functional recovery on repeat indirect laryngoscopy or on plain radiographs and polytomographs. Each of two parathyroidectomy patients whose lateral views were taken within a week after surgery showed a dilated ventricular air space, but without a delta sign, a n d both r e c o v e r e d f u l l y w i t h i n four months. One parathyroidectomy patient with a delta sign had not recovered normal laryngeal mobility a year after surgery and is considered irreversibly paralyzed. Three of four patients with h e m i l a r y n g e a l

RESULTS

In the normally mobile larynx the most common appearance of the ventricular air shadow as seen on the lateral view of neck soft tissue is that of a translucent horizontal ovoid seen at the approximate middle of the thyroid cartilage (Fig. 5). Among the 48 persons who had hemilaryngeal dysfunction, 18 patients who had undergone endotracheal intubation constituted the largest subgroup; none showed a triangular pattern of ventricular dilatation on the lateral neck views (Table 1). In each case, unilateral cord immobil-

of Hemilaryngeal Dysfunction Patients w i t h Dilated Ventricle with Delta Sign

Number

Number Recovered

11 "1 3

O 0 0

"1 3

0

1

0

0

Patients w i t h o u t Dilated Ventricle

Number

Number Recovered

Average Recovery Time (Months)

18

18

3

2

2

2

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ROENTGENOGRAPHYOF VOCALCORDDYSFUNCTION

Left, lateral view of neck soft tissue demonstratesabsence of any ventricul~r dilatationin the presence of immobile vocal cord secondaryto intubation. Right, same patient, showing classic tomographic signs of left hemilaryngeaidysfunction. Notice the obtusesubglottic angle {arrow) on the left and the normally effacingventricle on the right side (quiet breathing).

Figure 8.

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dysfunction and a dilated ventricle following laminectomy and/or fusion of the cervical spine through an anterior approach (Cloward's) had positive delta signs on lateral views of neck soft tissue within two m o n t h s after surgery. The patient who did not develop the triangular pattern of ventricular dilatation recovered full vocal cord mobility, while the other three patients had no recovery more t h a n two years after the procedure. A m o n g five patients w h o u n d e r w e n t carotid endarterectomy, two patients with ventricular dilatation but w i t h o u t a delta sign recovered normal laryngeal function within two months, and one patient with a positive delta sign has not recovered from unilateral vocal cord paralysis more t h a n three years after neck surgery (Fig. 9). In this group two patients who had hemilaryngeal dysfunction c o n f i r m e d by AP views and frontal tomography of the neck, but who showed no ventricular distention on lateral neck views, recovered full laryngeal f u n c t i o n w i t h i n two months. In the three cases of penetrating neck wounds, the soft tissue views were obtained within the first 24 hours of hospital admission. A gunshot caused the injury in one patient and stab wounds in the other two. These direct injuries to the inferior (recurrent) laryngeal nerve resulted in an irreversibly paralyzed vocal cord associated with

a persistent dilated ventricle of a triangular configuration as seen on repeat neck soft t i s s u e views. The patient with bulbar polio included in this study was first examined more than 30 years after diagnosis. The unilateral vocal cord paralysis in this patient was demonstrated on a lateral view of neck soft tissue by a dilated ventricle with a distinct triangular configuration (Fig. 6). The changing pattern of the ventricular air space in reversible l a r y n g e a l d y s f u n c t i o n is demonstrated by the roentgenograms of two patients who sought treatment within two hours after attempted heroin injection into the i n t e r n a l jugular vein. Both patients complained of immediate dysphonia and dysphagia, and indirect laryngoscopy showed unilateral vocal cord immobility, probably due to direct injury or infiltration of the inferior laryngeal or vagus nerves. The lateral neck views obtained within six h o u r s after the injury revealed dilatation of the ventricular air space (Fig. 10). Unilateral laryngeal dysfunction was confirmed by frontal tomography; however, the markedly distended ventricle did not assume the delta configuration, and both patients r e c o v e r e d full vocal cord m o b i l i t y within three months. One patient with a cervical spine fracture h a d a roentgenographic pattern similar to that demonstrated by the two addicts. The patient h a d

DEEB hoarseness, d y s p h a g i a , a n d unilateral dysfunction of cranial n e r v e s IX, X, a n d XII, three days after an altercation in w h i c h he sustained a disp l a c e d fracture of the posterior m a s s of the atlas (Jefferson's fracture). The lateral v i e w of neck soft tissue s h o w e d the e x p e c t e d distended ventrieular air s p a c e b u t w i t h o u t t h e delta pattern. T h e p a t i e n t r e c o v e r e d full l a r y n g e a l m o b i l i t y w i t h i n 12 m o n t h s after the accident, a l t h o u g h he r e g a i n e d f u n c t i o n in n e r v e s IX a n d XII t w o m o n t h s after the diagnosis. All patients w h o d e m o n s t r a t e d dilated vent r i c u l a r air s h a d o w s b u t n o d e l t a p a t t e r n t h r o u g h o u t the d u r a t i o n of unilateral i m m o b i l i t y s h o w e d c o m p l e t e r e v e r s a l to t h e normal ovoid configuration on lateral n e c k v i e w s taken after clinical recovery.

DISCUSSION U n g e r et al., 7 in 1960, a n d C a l d e r o n et al., s in 1964, m e n t i o n e d the use of lateral views of neck soft tissue briefly a n d q u e s t i o n e d its reliability in

Figure 10. Lateral view of neck soft tissue illustrates markedly dilated ventricular air column without a delta pattern in a patient who recovered completely from a cord paralysis within two months following injection of heroin into his neck.

Lateral view of neck soft tissue less than a week after carotid endarterectomy. This view shows a delta sign (arrow). This x-ray finding was consistent with irreversible hemilaryngeal paralysis.

Figure 9.

d e m o n s t r a t i n g c h a n g e s in v o c a l c o r d f u n c t i o n . In m o r e recent r e v i e w s on the v a l u e of lateral views of n e c k soft tissue in h e a d a n d n e c k disease, the use of this s i m p l e v i e w to d e m o n s t r a t e the ventricles is not m e n t i o n e d at all.J2 E x c e p t for r e c o m m e n d i n g a chest r o e n t g e n o g r a m a n d b a r i u m s w a l l o w e x a m i n a t i o n s , M a i s e l a n d Ogura ~a o m i t the use of r a d i o l o g i c m e t h o d s in t h e i r p r o p o s e d r o u t i n e e v a l u a t i o n of p a t i e n t s w i t h vocal cord paralysis. In his m a n u a l o n v o c a l c o r d paralysis, Doyle~4 does not m e n t i o n r a d i o g r a p h y as a v a l u a b l e d i a g n o s t i c tool w h i l e e m p h a s i z i n g more c o m p l i c a t e d m e t h o d s of e v a l u a t i o n , s u c h as s t r o b o s c o p y a n d e l e c t r o m y o g r a p h y . The c o n c l u s i o n s of this s t u d y s t r o n g l y disagree w i t h statements m a d e by o t h e r s 7's a b o u t the unreliability of the lateral a n d AP v i e w s in the e v a l u a t i o n of the p a r a l y z e d l a r y n x , a n d s u p port B a c h m a n ' s c o n t e n t i o n that t h e Y or d e l t a sign is characteristic o f v o c a l c o r d p a r a l y s i s . '~ This s t u d y also p r e s e n t s e v i d e n c e that the a p p e a r a n c e of a delta p a t t e r n in the v e n t r i c u l a r air space as seen on the lateral v i e w s of n e c k soft

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ROENTGENOGRAPHY OF VOCAL CORD DYSFUNCTION t i s s u e at a n y time after o n s e t of p a r a l y s i s is a r e l i a b l e s i g n of i r r e v e r s i b l e i m p a i r m e n t of the vocal cord. T h e l a t e r a l a n d A P v i e w s are s i m p l e a n d relat i v e l y i n e x p e n s i v e s t u d i e s for e v a l u a t i o n o f patients with laryngeal dysfunction. This study a t t e m p t s to c o n v e y a f u n d a m e n t a l u n d e r s t a n d •ng of t h e p l a i n r o e n t g e n o g r a p h i c a s p e c t s of laryngeal function. W h e n facilities for o b t a i n i n g c o m p l e x s t u d i e s of t h e l a r y n x are n o t a v a i l a b l e , or w h e n p a t i e n t s are u n a b l e to u n d e r g o s u c h t e s t s , t h e n p l a i n r o e n t g e n o g r a p h y of the n e c k m a y b e c o m e m o r e necessary. Valuable diagnostic and prognostic i n f o r m a t i o n m a y be o b t a i n e d in s i t u a t i o n s w h e r e o t h e r s t u d i e s c a n n o t be d o n e ,

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tamagraphy of the larynx. Radiol Clin North Am 16:195-208, 1978 Blair RL, Berry H, Briant TDR: Laryngeal electromyography. Techniques and application. Otol Clin North Am 11:325-346, 1978 Hsrrington JW, Christoforidis AJ: Radiological examination of the larynx. Laryngoscope 80:1773-1796, 1970 Woesner ME, Braun E], Sanders I: Xeroradiographic zonography of the larynx and hypopharynx. Ann Otal 83:42-48, 1974 Unger SM, Roswit B, Stein J: Vocal cord paralysis, a roentgen diagnostic study. Radiology 75:741-747, 1960 Calderon R, CebaIta~ l, McGraw J: Tomographic aspects of paralysis of the vocal cords. Radiology 03:407-419, 1954 Ma HTG: The radiologic signs of recurrent laryngeal nerve paralysis. J Canad Assoc Radiol 23:125-132, 1972 Meschan I, Martin iF, Rogers LF: Head and neck disorders, in: Theros EG (ed,): Syllabus of the American College of Radiology, set 5, section II. Chicago, 1974, pp 182-175 Bachman AL: Benign, non-neoplastic conditions of the larynx and pharynx. Radiol Clin North Am 16:273290, 1976 Principato JJ, Liebowitz M: Latersl x-ray film of neck. Arch Otolaryngol 93:505-510, 197l Maisel RH, Ogura ]H: Evaluation and treatment of vocal cord paralysis. Laryngoscope 84:302-316, ] 974 Doyle P]: Vocal Cord Paralysis, ad 2. Rochester, Minn., American Academy of Otolaryngology, 1979,