Surgical Treatment of Midline Fixation of the Bilateral Vocal Cords and its Functional Results

A.N.L., 1, 117-127, 1974

SURGICAL TREATMENT OF MIDLINE FIXATION OF THE BILATERAL VOCAL CORDS AND ITS FUNCTIONAL RESULTS Ichiro

KIRIKAE,

M.D. and Takeo

KOBAYASHI,*

M.D.

Department of Otolaryngology, lichi Medical School, Tochigi-ken *Department of Otolaryngology, University of Tokyo, Tokyo

Midline fixation of the bilateral vocal cords occurs on rare occasions. This condition has been described as bilateral abductor or posticus paralysis. However, the term of midline fixation or immobilization in median position is more adequate. During the past 17 years, 32 cases having this condition were seen in our clinic. Surgery for this condition and its functional results were discussed. To relieve dyspnea, Woodman's operation and the widening of anterior glottis operation were performed. On performing laryngoplastic surgery, we have to succeed on the first attempt, using a meticulous technique. Important points are not to fracture the thyroid or arytenoid cartilage and not to damage the laryngeal mucosa. Postoperatively, the patients' voice remained rather in intelligible condition. Postoperative respiratory function tests showed that improvement of lung volumes exceeded that of ventilation tests with a time factor. There were some discrepancies between the laryngoscopic findings and the results of postoperative respiratory function tests. Midline fixation of the bilateral vocal cords occurs on rare occasions. This condition has been described as bilateral abductor or posticus paralysis. However, the term of midline fixation, or immobilization in median position, is more adequate. In our clinic, electro myographic examination of the intrinsic laryngeal muscles is routinely done in these cases and we are usually able to record electrical activity from the posterior cricoarytenoid muscle (posticus). Therefore, this condition should not be called "paralysis." During the past 17 years, 32 cases of midline fixation of the bilateral vocal cords were seen in our clinic. This study was undertaken to analyze surgery, its functional results and other problems related to this condition. Received for publication September 7, 1973 117

I. KIRIKAE and T. KOBAYASHI

118

CASES

I.

Of 32 cases, 8 were male and 24 were female with their ages ranging rom 2 to 76 (Table 1). Seven patients, who had emergency tracheotomies, were discharged without further surgical intervention, because of young age, myocardial damage or refusal to undergo surgery. Twenty five cases underwent surgical treatment other than emergency tracheotomy. Of these cases, 23 were finally discharged with successfully decanulated condition. Table 1. Cases. Age and sex distribution. Age

Male

0-9 10-19 20-29 30-39 40-49 50-59 60-69 over 70 Total

Female

3

6 4 9 4 24

8

------~--------------

Comments Etiology. No definite cause was found in 15 cases (idiopathic type). In 12 cases, the condition occurred after thyroidectomy (post-thyroidectomy type). The other cases had neck trauma, deep neck infection and esophagectomy as possible causative factors (Table 2). In 1962, one of the present authors (KOBAYASHI et aI., 1962) reported that of 8 cases of midline fixation of the bilateral vocal cords, 7 cases were idiopathic type. The other one was due to laryngeal trauma. Cases of the post-thyroidectomy type tended to show an increase in this series. According to HOOVER (1932) and KELLY (1941), the most frequent cause was thyroidectomy. Other than neurogenic fixation, mechanical fixation of the cricoarytenoid joints, or the cords themselves, can take place following trauma or severe inflammation in this region. These causes should be observed carefully, because the cords often begin to move gradually as the accompanying local inflammation subsides.

Table 2. Etiology of midline fixation of the bilateral vocal cords. Etiology Idiopathic Thyroidectomy Deep neck infection Tuberculosis of the larynx Oesophagectomy Neck trauma

15 12 2

MIDLINE FIXATION OF BILATERAL VOCAL CORDS

119

Recently, the concept of misdirected innervation of the laryngeal muscles during the course of recovery from paralysis was introduced (SIRIBODHI et aI., 1963; TOMITA, 1967). In midline fixation of the bilateral vocal cords, the electrical activity was often recorded from the posticus muscle as previously described, though this muscle apparently did not move. This condition might be explained by the above concept. Symptoms. The patients' chief complaint was dyspnea, which appeared insiduously, or suddenly, and was marked during exertion. Inspiratory stridor was often heard. It should be noted that some patients were misdiagnosed by general practioners as having asthma. II.

SURGERY

In order to relieve the dyspneic condition of the patients, an effective air way has to be made first. Thus, most patients had already been tracheotomized when first seen in our clinic. The next step is to re-establish a good laryngeal air way, since they wanted to be decanulated and to take bath safely. * Before surgery, we routinely manipulate the arytenoids with a long curved laryngeal probe in order to examine the passive mobility. Theoretically, this passive mobility test is very useful in determining etiology. In some of our cases this test showed no mobility. This was probably due to fibrosis around the arytenoid joints resulting from long standing immobilization. In fact, in examining the arytenoid and its surrounding tissue which were removed at the time of operation, fibrosis was often found histologically. As mentioned previously, electromyographic examination of the intrinsic laryngeal muscles is often an indispensable test in determining etiology. Prior to any corrective surgery, except for emergency tracheotomy, a complete physical examination must be done. Patients in a post-thyroidectomy state are sometimes endocrinologically abnormal. One patient (case 23) had tetany during the course of hospitalization. In two cases, evidence of myocardial damage, probably due to dyspnea of long duration, was found in the electrocardiogram. These conditions make the patients definitely poor surgical risks. In the earlier cases of our series, all operations were performed under local anesthesia in order to obtain good cooperation from the patients for evaluating laryngeal function in voluntary phonation and forced breathing during surgery. However, as the surgery takes a fairly long time and relaxation of neck muscle tonus is needed, we now operate under general anesthesia. For widening the glottis, several techniques of laryngoplasty have been reported. Our patients were operated on mainly by Woodman's laterofixation of the vocal cord with arytenoidectomy via the extralaryngeal route. In some cases, we performed R6thi's operation and widening of the anterior glottis operation (KIRIKAE et at., 1969; SHITARA, 1972) (WAGO), if initial operations were inadequate for decanulation.

* When Japanese take bath, they have a custom to submerge themselves up to the level of their neck in hot water.

120

I. KIRIKAE and T. KOBAYASHI

We do Woodman's operation as described in the following manner. The thyroid ala is exposed via the extralaryngeal route. The arytenoid cartilage is freed from the attached intrinsic laryngeal muscles, except for the vocals muscle. The greater part of the cartilage is removed, leaving the vocal process intact. Then, a chromic catgut suture is attached at the vocal process area using a hookshaped needle and the vocal cord pulled laterally. The catgut suture is fixed at the inferior cornu, or the posterior margin, of the thyroid cartilage. We use an operating microscope at this stage of surgery. The important point is that an anchoring of the catgut should be accomplished on one attempt (Fig. 1: 1 and 2). Repeated attempts cause further difficulties. Before and after surgery, the glottis

@~ostop !''- (successful) !

i

~

.. ,

Fig. 1. Widening of the glottis, preoperative and post-operative, in successful cases. (1 and 2). Technical failures (3-7): fracture of the posterior margin of the thyroid ala and the inferior cornu (3, 7), fracture of the arytenoid cartilage (4), granulation tissue formation due to damage of the laryngeal mucosa (6) and loosening of the tie (5).

MIDLINE FIXATION OF BILATERAL VOCAL CORDS

121

should be examined under direct laryngoscopy. Final fixing of the suture to the thyroid cartilage should not be done until the glottis is scoped. In adult patients, calcification or ossification of the thyroid cartilage is prominent at the posterior margin. The arytenoid cartilage is also calcified. These cartilages are easily fractured by surgical procedures. This fracture causes failure to yield an effective widening of the glottis. This is one of the reasons for unsuccessful cases (Fig. 1: 3, 4 and 7). In this connection, lateral roentgenograms of the soft tissues of the neck should be routinely obtained preoperatively. This gives valuable information concerning ossification of the laryngeal cartilages preoperatively. During the procedure, the laryngeal mucosa should not be damaged in any degree, because any small damage of the laryngeal mucosa delays wound healing and results in insufficient glottal opening by excess scar tissue formation (Fig. 1: 6). When surgeons widen the glottis, they are always faced with a dilemma, that is, the better phonation, the poorer respiration. In this connection, considerable discussion needs to be carried out with the patients preoperatively. If a patient requires a highly delicate function of the voice, careful consideration must be given in deciding how much to open the glottal aperture. In our experience, however, a too widely opened glottis is hardly ever been obtained. In performing this type of surgery, relief of respiratory difficulty should be aimed in the first aim. In some cases, postoperative indirect laryngoscopy showed an insufficiently opened glottis and yet patients breathed easily via the mouth. One of the reasons was a difference between the level of the vocal cords. This was ascertained by tomography of the larynx. When, unfortunately, a sufficiently wide glottis was not obtained postoperatively, Woodman's operation was done on the contralateral side (case 14). In some cases (case 1, 2, 9, 14, 19, 22, 23) Rethi's cordectomy and widening of the anterior glottis operation (WAGO) were necessary. However, even after the second procedure of Rethi's operation, one patient could not be successfully decanulated (case 2). Case 14 was the most difficult case for us to treat and necessitated four operative procedures to achieve a good result. Recently, widening of the anterior glottis operation (WAGO) has replaced Rethi's cordectomy. The four cases in our series were operated on by the WAGO technique. As opposed to Woodman's operation, this was aimed at widening the anterior commisure of the glottis. Postoperatively, an inverse glottal triangle with the base anteriorly located was obtained. In performing this type of laryngoplastic surgery, a successful result on the first attempt is highly desirable. The more procedures added, the less favorable the results obtained. Scar tissue formation of the laryngeal mucosa becomes more marked on repeated attempts resulting in further laryngeal stenosis. Age, sex, etiology and operative treatment of all our cases are detailed in Table 3.

122

I. KIRIKAE and T. KOBAYASHI

Table 3.

Cases undergoing surgery other than tracheotomy only. Surgery Etiology except tracheotomy

Age

Sex

42

M

I

W,R

2

63

F

I

W,R

3 4 5 6 7 8 9 10

52 24 35 39 58 47 22 40 53 36 50 56 58 63 65 37 55 46 76 33 58 32 26

M M F F M F M F F F F M F F F F F F M F F M F

I I I Trauma deep neck infection Th I I Th Th Th Th Th I Oesophagectomy Th Th Th I Th Th deep neck infection I

W W W W R W W,R W W W W W,W,R WAGO W W W W,W W,WAGO W W WAGO WAGO W W

11

12 13 14 15 16 17 18 19 20 21 22 23 24 25

Comment discharged with tracheotomy

--.--.~--"---

I, idiopathic; Th, thyroidectomy; W, Woodman's operation; WAGO, Widening of the anterior glottis operation; R, Rethi's operation.

III.

FUNCTIONAL RESULTS

Few reports have been written on the functional aspects of midline fixation of the bilateral vocal cords and its surgical treatment. Postoperatively, subjective and objective changes occurred. Glottic stridor disappeared and the dyspneic condition was relieved. Howe~er, voice quality worsened. 1. Phonation Patients with chronically aggravated midline fixation usually obtained the most suitable speech habit by themselves, i.e. : posture during phonation, breathing mode, pitch, intensity, etc. They did not have much difficulty in normal communication. However, if a more delicate function of the voice was required, or a slight load was imposed, their phonation was markedly aggravated. Singing was not feasible in all cases. Slight physical fatigue or minimal upper respiratory

MIDLINE FIXATION OF BILATERAL VOCAL CORDS

123

tract infection worsened voice quality a great deal. The voice was not husky but less resonant. Much time was required in inspiration because of the stenotic glottis. Sentences were interrupted very frequently due to reduced tidal volume. Voice breaks, involuntary phonation of falsetto voice and inspiratory stridor were aggravating to listeners. Loud voice could not be phonated. Spoken pitch was out of the normal range, but not to any significant extent. Maximal phonation time was reduced, partially because of wild air and partially because of small tidal volume (Fig. 2). Postoperatively, a husky voice appeared in all cases. Two patient (case 12, 25) complained of complete aphonia due to wild air. Vocal range was narrowed. Vocal registers were not easily discriminated. Usual spoken pitch changed in most cases. Maximal phonation time markedly decreased. In most cases, however, speech intelligibility remained rather good. Most patients could talk on the telephone. HI CD EF G AHcd ef

S a he'd' ef g' ahe" d" e'

MPT

(sec)

case NO

19. 3.5

W

I

2

I

16 7

I

4

19.5

6

16 5

4

9

IS

10

II

9 10

lb

II

12

5 2

~

13

•

41

15 22 23

1

12 3.5

Ii

S.4

US

4

3

a:s

7.5

5 3 12 6

24 25

5 9

!

8

preop _ postopc:::::::J

12 5

Fig. 2. Vocal ranges are presented on musical scale in abscissa. Narrow vertical bars indicate usual spoken pitch. In cases 12 and 25, postoperative voice was almost aphonic and no definite measurement was made. MPT: maximal phonation time.

I. KIRIKAE and T. KOBAYASHI

124

Postoperative vocal change was mainly due to incomplete closure of the glottis. This was due to asymmetry of the vocal cords (bowing of the laterally fixed cord and level difference of the cords) and to changes in the laryngeal mucosa from surgical trauma. Compensately vibration of the false cords may develop postoperatively. Some of these changes were ascertained with stroboscopy and laryngeal tomography. There is no essential defference in postoperative voice quality between Woodman's operation and widening of the anterior glottis operation. 2. Respiration Postoperatively, patients felt comfortable in breathing, if a glottal width of 3 to 4 mm was obtained (ARNOLD, 1959). Twenty three patients subjectively and objectively improved as manifested by successful decanulation. Respiratory function tests were done in 10 cases before and after surgery in order to evaluate objective improvement. In the preoperative tests, the tracheostoma was tightly corked. Postoperative tests were done after successful decanulation and complete closure of the tracheostoma. Preoperative respiratory function tests showed markedly increased residual volume and a tendency to increased total lung capacity. Timed expiratory flow rate showed a poor score and maximal breathing capacity was markedly reduced. Vital capacity was reduced, except in two patients. These results indicated that the patient had to breathe with the lungs overextended and dynamic components of respiratory function (ventilation) were particularly affected. In other words, the preoperative condition resembled emphysema or asthma. Postoperatively, these conditions were considerably improved in our series. Vital capacity increased and residual volume decreased in all cases. Total lungs capacity remained almost unchanged. Maximal breathing capacity became better. Timed expiratory flow rate improved. One patient resumed a normal value in 3 second flow rate volume. According to the parameter of maximal mid-expiratory flow, 3 patients improved. As the above data show, measurements of lung volumes improved in all patients. However, timed ventilation test showed less

iI r--t~------~~------~~~--------------~~--------~.. ::l

rn ><

"

~I

::l

~-------------

Fig. 3. Spirogram. Quiet respiration was followed by forced inspiration and expiration. Obstructive respiratory disturbance improved postoperatively, that is, vital capacity increased and residual volume was reduced. Note inspiration (large arrow) was much more improved than expiration (small arrow).

MIDLINE FIXATION OF BILATERAL VOCAL CORDS Table 4. Case 4

6

7

8

9

12

13

15 16 20

normal preop postop normal preop postop normal preop postop normal preop postop normal preop postop normal preop postop normal preop postop normal preop postop normal preop postop normal preop postop

Respiratory function tests.

VC

RV

TLC (I)

RV/TLC (%)

(l/min)

3.80 3.44

0.96 1. 74 1.28 1.20 1.48 1.34 1.45 3.05 2.52 1.0 1. 74 1.22 0.96 1.54 1.62 0.87 2.39 1.25

4.75 5.17 4.94

<35 33.6 25.8 <35 46.1 33.8 <35 48.4 42.4 <35 40.0 28.4 <35 28.7 25.8 <35 53.2 30.5 <35

109.0 42.0 51.5 82.0 22.4 32.0 78.9 54.5 71.0 62.2 28.0 52.5 119.0 58.5 81.3 75.1 27.8 54.8 62.7 22.3 59.0 62.3 37.4 46.8 46.5 21.3 24.5 67.0 17.0 54.0

(I)

4.04

2.90 1.88 2.95 3.35 3.25 3.45 2.60 2.60 3.07 3.89 3.82 4.66 2.83 2.10 2.85 2.49 2.17 2.23 2.35 2.83 3.23 2.12 2.00 2.22 2.58 2.97 2.94

(I)

1.10

*

1.37 1.05 1.89 1.40 0.95 1.89 1.23 1.10 1.44 1. 75

125

* *

*

4.28 6.30 5.97 3.65 4.35 4.29 4.87 5.36 6.27 3.74 4.49 4.10

* * *

3.39 4.72

4.63

* *

* *

* *

*

38.1 -35 40.0 30.3 -35 48.5 35.6 -35 32.7 37.0

MBC

TVC (%) 1 sec 3 sec

82 42 35 82

*

*

82 77 72

82 55 74 82 76 77

82 72

81 82 65 86 82 76 65 82 60 64 82 65 79

100 90 93 100 81 98 100 92 97 100 90 94 100 91 98 100 99 97 100

* *

100 95 87 100

*

89 100 93 89

.~----------

MMF (I/sec)

4.57

* *

3.71

1.13 1.11 3.20 2.32 1.97 2.73 0.98 1.86 4.57 4.16 3.38 3.71 1. 51 2.62 2.40 1.23 2.82 2.40 1.92 1.14

2.09 0.93 1.01 2.73

* *

---

Normal, preoperatively estimated normal value; VC, vital capacity; RV, residual volume; TLC, total lung capacity; MBC, maximal breathing capacity; TVC, timed vital capacity; MMF, maximal midexpiratory flow; *, not tested.

improvement. This indicated that patients would still have some difficulty with physical exertion. These data are summarized schematically in Fig. 3 and in detail in Table 4. In these tests, inspiratory flow rate was not measured. According to LILLIE (1964), this parameter showed marked improvement in his series. Considering the shape of the subglottal dome, expiration was thought to be little influenced by a slight widening of the glottic aperture, while inspiration was felt to be much improved. There were some discrepancies between the results of the respiratory function tests and laryngoscopic findings. Some cases showed marked subjective improve-

126

I. KIRIKAE and T. KOBAYASHI

Fig. 4. Relationship between laryngeal findings and respiration. Though the glottal opening is wider in case 7 (left), respiration test showed more marked improvement in case 12 (right). Numbers indicate the actually measured length and width of the glottis.

ment with objective evidence of improved respiratory function, but did not show a wide glottis on postoperative laryngoscopy. To evaluate this point, we attempted to measure the width of the glottis. As operating microscope having a specially designed ocular lens with a scale and a protractor was used. Opening of the glottis was apparently wider in case 7, while in the respiration test, improvement was more marked in case 12 (Fig. 4). The degree of glottal opening was not necessarily parallel to respiratory improvement. IV. SUMMARY

1) Midline fixation of the bilateral vocal cords is a rare condition. The etiology is stilI under discussion. In our series, idiopathic type and post-thyroidectomy type were frequent. 2) To relieve dyspnea, Woodman's operation and the widening of anterior glottis operation were performed. On performing laryngoplastic surgery, success on the first attempt, using a meticulous technique, is vital to optimal results. Important points are not to fracture the thyroid or arytenoid cartilage and not to damage the laryngeal mucosa. 3) Postoperatively, the patients' voices remained intelligible. Postoperative respiratory function tests showed that improvement in lung volumes exceeded that of ventilation tests with a time factor. There were some discrepancies between the laryngoscopic findings and the results of postoperative respiratory function tests. We express appreciation to Dr. Robert C. Meredith, US Naval Hospital, Yokosuka, for his kind help. REFERENCES ARNOLD, G. E.: Vocal rehabilitation of paralytic dysphonia. Arch. 0101.70: 444-458, 1959. HOOVER, W. B.: Bilateral abductor paralysis. Arch. 0101. 15: 339-355, 1932. KELLY, J. D.: Surgical treatment of bilateral paralysis of the abductor muscles. Arch. 0101. 33: 293-304, 1941.

MIDLINE FIXAnON OF BILATERAL VOCAL CORDS

127

KIRIKAE, I., SHITARA, T., KURAUCHI, Y., and TAKEMOTO, K.: Surgical restitution of chronic stenosis of the larynx and cervical trachea. J. Japan Broncho-Esophagol. Soc. 20: 18-27, 1969. KOBAYASHI, T. et al.: Bilateral immobilization of the vocal cords in median position with reference to clinical evaluation as guide to surgical therapy. Jap. J. 0101. Tokyo 65: 10781087, 1962. LILLIE, J. C.: Pulmonary function before and after arytenoidectomy. Arch. 0101. 80: 170--173, 1964. SHITARA, T.: Surgical treatment of chronic laryngeal stenosis caused by trauma. J. Japan Broncho-Esophagol. Soc. 23: 65-72, 1972. SIRIBODHI, C. et al.: Electromyographic studies of laryngeal paralysis and regeneration of laryngeal motor nerves in dogs. Laryngoscope 73: 148-164, 1963. TOMITA, H.: An electromyographic study of recurrent laryngeal nerve paralysis. Jap. J. Otol. Tokyo 70: 963-985, 1967. Request reprints from: Dr. T. Kobayashi, Department of Otolaryngology, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan