Ann otoi 88 :1979
LARYNGEAL PARALYSIS TEFLON® INJECTION
WILLIAM W. MONTGOMERY, MD BOSTON, MASSACHUSETTS
This report is a review of the literature combined with the author's experience concerning Teflon injection of the larynx. Included are the etiology and diagnosis of vocal cord paralysis, indications and contraindications for Teflon injection of the larynx, its histopathology, preand postoperative management, proper and improper techniques for injecting Teflon, complications, and reasons for failure.
Unilateral vocal cord paralysis in the partially abducted position (paramedian) can produce a number of distressing symptoms caused by air waste during attempted phonation and inadequate approximation of the cords during swallowing and coughing. In 1911, Brunings,' a German laryngologist, devised a technique of injecting the paralyzed vocal cord with hard paraffin using a syringe of special design. This technique was very successful but later abandoned since the paraffin implant frequently extruded and produced a now well-known complication, paraffinoma. In 1955, Arnold" revived Briinings' technique using autogenous and homogeneous cartilage particles. Subsequently, a number of materials were used: autogenous cartilage graft," heterogeneous bovine bone paste;' tantalum oxide;" Teflon;" tantalum powder," and silicone." Teflon paste (polytef PTFE, Mentor Division of Codman and Shurtleff, Inc., Randolph, MA), a polymer of tetrafluoroethylene, is the most inert of all known plastic materials and has a density of 2.4. The Teflon powder is mixed with glycerin as a vehicle using an equal volume of each substance. The Teflon powder with its small particle size, fulfills all of the criteria for the ideal substance for intracordal injections: 1) it is well tolerated by tissues, 2) it is resorbed in time, 3) it is finely dispersed in a harmless vehicle so that it may be injected through a long needle using the Bruening syringe (Storz Instrument Co., St. Louis, MO.)
During a decade before its use in the larynx, Teflon had proven to be well tolerated by human tissues in thousands of cases of stapedectomy and in its use as an arterial substitute. In 1962, Arnold" published his results from laboratory experimentation with the Teflon-glycerin mixture and also its clinical use for the rehabilitation of paralytic dysphonia. Kirchner et aPO performed experimental studies from 1963 to 1965 using Teflon on the canine larynx for H~ years duration. They demonstrated that there were no carcinogenic effects of Teflon, that Teflon was inert and well tolerated by tissues, Teflon had no necrosing effect on cartilage, and the implant became surrounded by a fibrous capsule. In 1963, Lewy" published a comparative analysis of tantalum-glycerin and Teflon-glycerin mixtures. He found that both mixtures were well-tolerated by the tissues with minimal reaction, that there was no drift of the injected material, and that the situation resulting from the injection was not altered with the passage of time. He also concluded that the Teflon-glycerin mixture was preferred because it is easier to use and can be prepared in advance. Stone and Arnold'" stated after histological studies following Teflon injection in the human, that Teflon was definitely not carcinogenic, there was a minimal foreign body reaction with the Teflon, there was no reaction in the surrounding tissues (both muscle and cartilage), and that the Teflon was surrounded by a fibrous capsule. Thus, by 1966,
From the Department of Otolaryngology, Harvard Medical School and the Massachusetts Eye and Ear Infirmary, Boston. Massachusetts.
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TABLE 1. CAUSES OF VOCAL CORD PARALYSIS13
Cause Head Brain injury Vascular accident Neck Thyroid disease and surgery Trauma Laryngeal surgery Cordectomy Neck surgery Bowed vocal cords Laryngeal Tumor Benign and malignant Carcinoma of the esophagus Chest Lung Benign tumors Malignant tumors Infection Tuberculosis Sarcoidosis Pneumonia Heart enlarged Aortic aneurysm Chest injury Chest surgery Carcinoma of the breast Heart surgery Neurological Parkinson disease Meningitis Metastatic carcinoma Poliomyelitis Other Idiopathic
Estimated % 4
44
30
4
18
polytef had proven to be safe for clinical usage. At that time however, its usage was limited to a relatively small number of laryngologists since the technique of injection was considered difficult, and the selection of cases was thought to require the judgment of an accomplished laryngologist. Teflon-glycerin has now been available for general usage since 1972. ETIOLOGY OF UNILATERAL VOCAL CORD PARALYSIS
Rontal et aJt2 state that approximately 10% of the mown causes of vocal cord paralysis have a central etiology. These include cardiovascular problems, brain abscess, syphilis, Parkinson disease, mul-
TABLE 2. CAUSES OF VOCAL CORD PARALYSIS (N 135)14
=
Cause Surgery: head or neck Malignancy: nasopharynx, neck, chest Idiopathic Traumatic Surgical excision or traumatic loss of cord substance Infections (polio, TB) CVA or brain stem injury Radiation therapy Congenital bilateral bowed mobile cords
No. patients 53 27 29 6 9 3 3 1 4
tiple sclerosis, syringobulbia, medullary tumors, and amyotrophic lateral sclerosis. Peripheral involvement of the recurrent laryngeal nerve probably accounts for the remaining 90%. Of importance is the fact that the left recurrent laryngeal nerve is involved more commonly than the right by a ratio of 10:1. Rontal et al state that lesions of the vagus nerve above the take-off of the superior laryngeal nerve will result in the cords maintaining the intermediate (abducted) position over a long-term period. They state that the recurrent laryngeal nerve section results in the cord gradually returning to the midline position. Lewy'" lists the causes of vocal cord paralysis as in Table 1. He found idiopathic vocal cord paralysis, carcinoma of the lung and thyroid surgery to be the three most common causes for unilateral vocal cord paralysis. Dedo et alB list the causes of vocal cord paralysis as in Table 2. INDICATIONS FOR TEFLON INJECTION
Rontal et aJt2 state that in order to relieve aspiration in acute paralysis following sectioning of the recurrent laryngeal nerve, the vocal cord should be injected as a planned procedure the day following sectioning. They prefer this to Lewy's technique'" using glycerin since the natural history following traumatic section of the recurrent laryngeal nerve is for the affected vocal cords to gradually migrate to the midline. The vocal cord injection, according to Rontal et al, is a benign procedure which can be performed using local anesthesia the day
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6-19
following major surgery with little risk for Teflon injection. In these patients to the patient. The results following there are the following findings: 1) asthese injections are very gratifying since piration, 2) ineffective cough, 3 ) the restoration of cough and prevention breathy hoarseness, 4) poor oxygenation of aspiration allow for a more rapid re- of the blood due to decreased alveolar covery of the patient and often prevents pressure, and 5) inability to laugh. the necessity of a tracheotomy. In patients with aspiration and poor CONTRAINDICATIONS FOR TEFLON phonatory function following subtotal INJECTION laryngectomy, Yarington et al'" state 1. In cases of bilateral vocal cord pathat Teflon injection will relieve this ralysis in the paramedian position," condition and prevent the need for a there is too great a chance for narrowing subsequent total laryngectomy. They the airway and the necessity for an also speculate that Teflon paste would emergency tracheotomy following a Tefnot be well tolerated in those patients lon injection. If a Teflon injection is to who have received radiation therapy. be entertained in such a situation, it Arnold" lists the following indications: should be done along with a trache1. In cases of unilateral vocal cord pa- otomy. ralysis where a) there is hoarseness due 2. Minor defects in the glottic chink to waste of air; b) there is an ineffective should have an attempt for vocal rehacough mechanism; and c) there is de- bilitation by vocal therapy before recreased intra-alveolar pressure; the pro- sorting to a Teflon injection," cedure is indicated. He states that the 3. Injection of Teflon should, as a laryngeal injection of Teflon is indicated mainly in the condition of complete pa- rule, not be attempted for 10 to 12 ralysis of the recurrent laryngeal nerve months following the onset of unilateral with intermediate position of the atro- vocal cord paralysis for the following reasons: a) spontaneous return of funcphic and bowing paralyzed cord. tion with an intact recurrent laryngeal 2. Congenital dysplastic dysphonia is nerve may occur up to 12 months after the result of hypoplasia of the vocalis onset; and b) the paralyzed vocal cord muscle in both sides of the larynx with may gradually migrate to the midline a resultant hypotonic, bowing, vocal position with return of good phonatory cord paralysis. He advises injection first and sphincteric functions. of one vocal cord and, if not effective, 4. Injection of Teflon to improve vocal the opposite cord should be injected as function after a successful arytenoideca separate procedure. tomy is, in my opinion, contraindicated 3. In cases of cordectomy or hemi- because of the possible embarrassment laryngectomy Teflon paste can be used of the laryngeal airway and irreversible to fill the defect and improve phonatory return to a tracheotomy. function as well as preventing aspira5. If it can be determined that psychotion. genic factors" are related to the dys4. Vocal cord defects resulting from phonia, Teflon should not be injected reexcision of benign lesions of the vocal gardless of the clinical picture. Unforcord such as nodules, polyps and papil- tunately however, this diagnosis is very lomas, are indications for the procedure. difficult to establish. 5. Arnold proposed the injection of 6. Arnold" states that cases of incomTeflon to improve vocal function after plete auditory monitoring (or congeniarytenoidectomy. In my opinion, there tal amusia) should not be injected with is too great a risk in this situation for Teflon. embarrassment of the airway and ir7. Rubin" states that myasthenia reversibly returning the patient to a prearytenoid status and a permanent laryngis and hypogenesis vocalis are tracheotomy. contraindications to Teflon injection. Lewy-" lists unilateral vocal cord paralysis as the most common indication
8. Dedo et aP4 also list scar band pseudocord and central nervous system
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lesions where dysphonia is caused by complex dysarthria as contraindications to Teflon injection. DIAGNOSIS
Diagnosis of unilateral vocal cord paralysis in the abducted position can be easily established with indirect laryngoscopy by observing the larynx during inspiration and attempted phonation. The patient may also give a history of aspiration and difficulty with swallowing, especially liquids. By listening to the patient talk, it can easily be determined that the hoarseness is of a breathy type and that he is able to speak a limited number of words following inspiration due to the inefficiency caused by air leakage during phonation. It can also be noted that the patient has a poor cough mechanism and may not be able to laugh. It has become vogue to tape-record the patient's vocal function before and after the Teflon injection. I suspect that this is a fine method for documenting the pre- and postoperative voice for the purpose of teaching. Lewy'" states that voice tapes form a permanent record which is invaluable in evaluating results for legal protection and persuasion. He goes on to say that tapes, however, have a disadvantage as they are not objective. Expert judges vary in the interpretation of changes of voice quality. Eighty-two of Lewy's pre- and postoperative tapes were evaluated and resulted in a subjective analysis of a 60% success rate as compared to his personal estimation of about 90% success. I personally doubt that they would be of value in court and feel that it is unfair to use tape recordings as a method of persuading the patient to agree to the operation. I have found very few patients who are interested in listening to the recordings of their voice. They, and those close to them, evaluate the result of the Teflon injection simply by listening to the voice. Rontal et a)16 advocate voice spectography for analyzing the voice pre- and postoperatively. They state that there are three characteristics identifiable to spectographic analysis that are related to a paralyzed vocal cord: excessive breathiness, aperiodicity of vocal cord
movement, and a breakdown in formant structure. Lewy'" has recorded cough sonograms before and after Teflon injection to demonstrate the improvement in cough effectiveness. Some laryngologists advocate an analysis of the vocal dysfunction by a vocal therapist before and after Teflon injection. This is done so that vocal therapy may be utilized if the degree of voice improvement is not satisfactory following the Teflon injection. I feel that this is a needless expense to the patient and that a vocal therapist can carry out his instruction just as effectively without a preoperative analysis. Von Leden et al," as a research project, studied vocal function pre- and postoperatively by using high speed photography, aerodynamics and acoustic studies. This certainly is not practical in clinical practice. They did however, demonstrate that patients experienced an immediate clinical improvement following Teflon injection and that the functional studies suggest that laryngeal tissues require approximately one month for physiological adaptation to the Teflon implant. mSTOPATHOLOGY OF TEFLON INJECTION
Animal experiments'" in 1966 demonstrated that laryngeal injections of Teflon paste result in an early acute inflammatory response followed by a persistent chronic foreign body reaction. Minimal fibrosis in a fibrous capsule surrounds the implant. The original volume and position of implants are well maintained both because the glycerin is replaced volumetrically by a cellular infiltrate and because the 50-100 micro-Teflon particles are larger than the local lymphatics. Teflon is well tolerated by tissues because of its chemical inertness and insolubility, and because it is nonantigenic. Stephens et a}19 describe the pathology as a foreign body reaction with giant cells, few lymphocytes, and no polymorphonuclear leukocytes during the early stage and later, a bland reaction of a chronic type with a fibrous capsule and advancing fibrosis. In no instance did they find any evidence of carcinogenicity. Boedts et al 2 0 reported the results of
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canine experiments in 1967. These experiments demonstrated the stability of Teflon paste even after two years following the injection. The Teflon was found to be inert chemically and well tolerated. They found no mechanical migration of the Teflon implant. The Teflon caused no necrosis of laryngeal cartilage and there was no evidence of carcinogenic effects. It is of note that Teflon particles were found adjacent to and in lymphatics and small blood vessels. There was however, no evidence of spread of Teflon beyond the confines of the larynx or to distant parts of the body. Kirchner et al l o in canine experiments performed from 1963-1965, demonstrated that Teflon-glycerin mixture was effective in displacing a paralyzed vocal cord medially and that there was no carcinogenic effect. They also found Teflon to be inert, well tolerated by tissues, that it did not produce necrosis of cartilage and that the implant became surrounded by a fibrous capsule. Lewy's study of the pathology of intralaryngeal injection of Teflon paste performed in 1966 demonstrated that the mild inflammatory reaction was replaced by a fibrous capsule formed around the Teflon paste which had been injected, that there was no evidence of carcinogenicity. Stone and Arnold'! demonstrated in 1966 that Teflon produced a foreign body reaction which was surrounded by a fibrous capsule. These studies indicated that Teflon was not carcinogenic. PREOPERATIVE INFORMATION FOR THE PATIENT
Preoperatively, the patient should be told why he is experiencing a breathy hoarseness, aspiration and an ineffective cough. The patient is informed that the procedure involves a direct laryngoscopy, ie, the introduction of an illuminated metal tube into the throat. During the procedure, a needle, which is attached to a pressure syringe similar to a caulking gun, is introduced through the laryngoscope and into the tissues outside the paralyzed vocal cord. The bulk of the implant causes the paralyzed vocal cord to be moved in the direction of the opposite functioning vocal cord. This
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enables the functioning cord to strike against the paralyzed cord, thereby improving the voice and cough and preventing aspiration. It is explained to the patient that there is approximately an 80% chance for improvement and a slight chance that the condition might worsen. The main reason for failure is that it is difficult to control the exact positioning of the Teflon paste in the tissues and, in some instances, the Teflon drifts to adjacent tissues as it is being injected. The patient should also be informed that there is a possibility for failure and complication as there can be with any operation and anesthesia. TECHNIQUE OF ANESTHESIA
The anterior floor of mouth, pharynx and larynx are anesthetized with 4% cocaine solution. Two cubic centimeters of Xylocaine® solution without epinephrine are injected just below the tip of the greater horn of the hyoid bone on each side in the region of the thyrohyoid membrane. This will provide excellent anesthesia of both superior laryngeal nerves. Two cubic centimeters of 4% cocaine solution are injected into the cervical trachea. The anesthesiologist then injects 1 cc of Inovar® solution intravenously. After approximately 15 minutes additional Inovar is administered until the patient nears general anesthesia but will still respond to requests to phonate. The patient must, of course, be encouraged to take deep breaths during this period. TECHNIQUE OF TEFLON INJECTION
The patient is placed in the position for direct laryngoscopy and an anterior commissure laryngoscope is introduced. If elevation of the epiglottis is painful, produces gagging, or a laryngospasm, then additional 4% cocaine solution is sprayed directly through the laryngoscope. A laryngeal needle with a 19 or 20 gauge tip is used along with a Bruening syringe (Fig. 1). The Bruening syringe must be promptly loaded and tested immediately prior to injection in order to assure that the Teflon flow is smooth (Figs. 15). Teflon paste must not be introduced into the syringe the day prior to its us-
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WILLIAM W. MONTGOMERY
Fig. 1. Photograph of the ArnoldBruening intralaryngeal Teflon injection set.
age since the result will be either underor overinjection of Teflon. Both the needle and the Bruening syringe must be carefully cleaned after their usage with ethyl alcohol. Some practice is required in order to accomplish expertise with the Bruening syringe. Teflon continues to flow from the needle tip after each click and there is no method to determine the exact amount being injected other than to keep a careful eye on the cord being injected. It is also essential that the site of the injection be clearly visible as the Teflon paste is being injected. Simultaneously, the patient should phonate gently on command so that the proper end point can be established. As soon as
Fig. 3. The needle is screwed onto the loading chamber and tightened with the wrench. Continued squeezing of the tube will force Teflon paste into the needle.
the end point of voice return is reached, the injection should be immediately ceased. The laryngeal needle is introduced through the anterior commissure laryngoscope so that its tip is at the level of the true vocal cord. The bevel of the needle tip should be facing medially
Fig. 4. The tube and loading adaptor are removed from the loading chamber when a smooth continuous ribbon of paste emerges from the tip of the needle.
( Fig. 6a). The tip of the needle is moved laterally over the superior surface of the paralyzed vocal cord until it displaces the false cord slightly in a lateral direction (Fig. 6b). With the needle in an oblique lateral direction, it
Fig. 2. The cap is removed from the tube which contains 7 cc of Teflon paste. After puncturing the seal of the tube, the loading adaptor is screwed onto the tip of the Teflon paste tube. The loading adaptor is inserted into the proximal end of the loading chamber. The end of the Teflon paste tube is rolled up and the tube squeezed with one hand as the loadingchamber is held in the other. It takes considerable pressure and a few minutes to fill the loading chamber.
Fig. 5. The loading chamber is attached to the handle of the syringe and tightened with a wrench.
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LARYNGEAL PARALYSIS , I
Thyroid cartilage Folse vocal Laryngeal ventricle
Lot thyroarytenoid m. Med. thyroarytenoid m. (vacalis rn.)
~~I--_ Conus
elasticus
Lot. cricoarytenoid m. Cricat hyroid m. CricOid cartilage
(b)
(0)
Porolyred side
Functioning side
Teflon injection advancing true card to midline
(d)
(c)
Dolled lines simulate adduction of functioning cord
Fig. 6. a) The needle is introduced through an anterior commissure laryngoscope to the upper medial margin of the midligamentous vocal cord. b) The tip of the needle is then moved laterally so as to displace the false vocal cord laterally and advanced to the lateral aspect of the laryngeal ventricle. c) The needle (size 18 or 19) is introduced into the lateral aspect of the lateral thyroarytenoid muscle. The depth of this injection depends on the size of the larynx, ie, the depth in a small female larynx may be 3 mm and a large male larynx 5 mm, The depth can be estimated by remembering that the total length of the needle tip is 14 mm. d) Approximately 0.3 to 1.0 ml of Teflon paste is needed to reach the end point which is approximation of the ligamentous cords during phonation. Each click of the Bruening syringe delivers about 0.2 ml of Teflon paste providing time is allowed for compression and dissipation of the paste. There should thus be a delay of about 15 seconds between clicks. It is possible to deliver about 1.6 ml of Teflon paste with one loading of the Bruening syringe. The actual amount of Teflon retained in the tissue, of course, depends on the amount which exudes from the mucosal puncture site after the needle is removed. A second injection is usually required into the lateral thyroarytenoideus muscle at a point along the vocal cord easily identified by the tip of the vocal process medially so that the posterior commissure can be closed during phonation.
is advanced through the floor of the ventricle and into the substance of the lateral thyroarytenoid muscle (Fig. 6c). The first injection is made midway be-
tween the anterior commissure and the vocal process of the arytenoid. This injection is continued until the patient can approximate the opposite cord against
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(e)
(0
Fig. 7. a) Some Teflon injection needles come with a cuff or guard placed 4.5 mm from the end of the needle tip. (See text for details.) b) Coronal section of the larynx through the midligamentous portion of the vocal cord. The needle injection is shallow. Teflon will be deposited submucosally and result in obliteration of the laryngeal ventricle and no medial displacement of the vocal cord. c) Injection is in the proper direction but too deep. Teflon paste will be deposited in the lateral cricothyroid muscle or through the cricothyroid space and outside the larynx. In such cases, a mass may be palpated in the neck. d) The needle is placed too medially and deeply between the mucosa and the conus elasticus. This injection will result in a subglottic bulge. e) The needle is directed too medially and deeply and the tip penetrates the subglottic mucous membrane. As Teflon paste is injected, it can be visualized entering the subglottic lumen. f) The needle is introduced into the medial thyroarytenoideus. This infiltrates the vocalis portion of the thyroarytenoideus muscle and serves only to immobilize this area rather than displace the vocal cord medially.
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LARYNGEAL PARALYSIS
the side being injected while phonating (Fig.6d). Some authors advocate the use of a needle guard to prevent advancing the needle beyond a depth of 4.5 mm. The ideal depth in any particular case however, will vary with the size of the larynx. Also, the needle guard may give a false sense of security in that injections far beyond a depth of 4.5 mm can result as the needle guard indents the mucous membrane of the laryngeal ventricle (Fig. 7a). The amount of Teflon paste necessary will, of course, vary with the size of the larynx and the degree of lateral displacement of the paralyzed vocal cord. It is best to err on the side of underiniection rather than overinjection for Teflon, once injected, is difficult to remove. The needle should remain in place as long as possible following the injection. This will minimize the amount of Teflon paste lost since some Teflon paste exudes from the puncture in the mucous membrane after the needle is removed. On occasion, one injection is sufficient to restore good phonatory function. A second injection, however, is usually necessary. This is accomplished just lateral to the anterior aspect of the vocal process of the arytenoid and serves to close the posterior commissure. Again, it is difficult to estimate the amount of Teflon used in any given case as the Bruening syringe is not calibrated, some Teflon continues to flow from the tip of the needle after it is removed, and a varying amount of Teflon paste exudes from the needle puncture site after the needle is removed. An estimate of 1.00-1.50 cc of Teflon probably means that 0.75-1.00 cc of Teflon paste was actually retained in the tissues. It was earlier thought that the Teflon injection remamed as an encapsulated mass restricted to the region of the lateral thyroarytenoideus muscle. A number of histopathology reports are now in the literature.8 , l1 , 1 5 ,1 9 , 21 These studies demonstrate that Teflon paste often extends into the lateral cricoarytenoideus muscle and also through the cricothyroid space and even extralaryngeallv. This, for the most part, has not been clinicallv significant in that there was very good
655
rehabilitation of the laryngeal disorder in each case and there were no complicating signs and symptoms, except in one case where the extralaryngeal mass was misinterpreted as a thyroid nodule. It is thus obvious that a certain amount of drift and misplacement of the Teflon paste will occur regardless of the technique and skill of the surgeon. POSTOPERATIVE COURSE
As a general rule, the patient will complain of postoperative pain localized to the side of the larynx injected. This is especially true when it has been necessary to inject lateral to the vocal process of the arytenoid in order to close the posterior commissure. By indirect laryngoscopy, it can be observed the following day that the injected vocal cord is usually swollen. The mucous membrane of the laryngeal ventricle is also edematous and may be slightly prolapsed. The postoperative vocal function will gradually improve over a two to four-week period until it reaches its level of permanent improvement. Complications 1. Swelling may occur as a reaction to the Teflon injection. I feel that it is wise to administer 6-8 mg of Decadron® intraoperatively and at the end of two 6hour periods in order to prevent postoperative edema resulting from the reaction to the injection. A number of investigators have reported respiratory distress and stridor occurring within 24 hours after the iniection. 8 , 1 3, 1 5 , 21 , U Patients were successfully treated by using intravenous cortisone, ampicillin and steam inhalations. A number of cases of severe edema have been reported, necessitating a temporary tracheotomy. In all cases the edema gradually subsided and the tracheotomy was removed. This complication however, can usually be avoided by using cortisone before and after the implantation of the Teflon. 2. Pain, which usually subsides in about a week, may persist for many weeks. 3. Expectoration of Teflon particles or blood-tinged saliva may Occur during the first one or two postoperative days and should not disturb the patient.
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4. Granuloma formation at the site of the injection is a slight possibility. This can be removed by way of laryngoscopy and its recurrence prevented by injecting cortisone into the region of the implant. POSSIBLE REASONS FOR FAILURE FOLLOWING TEFLON INJECTION
1. Improper intracordal placement of Teflon can result in failure. The ideal situation for placement of Teflon is in the lateral thyroarytenoideus muscle as is shown in Figure 6d. The injection into the lateral aspect of the thyroarytenoideus muscle produces a shift of the muscle in a medial direction with minimal infiltration of the oscillating portion of the cord. It is not uncommon however, for the Teflon to migrate towards and into the false vocal cord, into the lateral cricoarytenoideus muscle and even extralaryngeally during the Teflon injection. As long as the Teflon paste does not infiltrate the oscillating portion of the vocal cord, these latter extensions of Teflon paste do not seem to interfere with a good result.
2. If the needle is placed too superficially (Fig. 7b), the needle tends to infiltrate the submucosal space of the larvngeal ventricle and obliterate it rather than infiltrate the lateral thyroarytenoideus muscle. Usually, this type of injection can be readily observed as it occurs and can be corrected by inserting the needle to a greater depth. 3. If the needle is directed at the proper angle into the cricoarytenoid space, the Teflon will occupy the cricothyroid and lateral cricoarytenoideus muscle (Fig. 7c) and may even escape extralarvngeally to the neck. This does very little in causing a medial disnlacement of the paralyzed vocal cord. When this type of injection occurs and there is no perceptible shift of the vocal cord in a medial direction, there mayor may not appear a bulge immediatelv beneath the level of the vocal cords. The situation can be corrected by withdrawing the
needle into the lateral thyroarytenoideus muscle and injecting an additional small amount of Teflon paste. 4. If the needle is directed in a straight inferior direction rather than an oblique lateral direction, and does not penetrate to the conus elasticus muscle, there will appear a very obvious bulge in the immediate subglottic region (Fig. 7 d). When this occurs, the needle shonld be withdrawn and directed laterally into the lateral thyroarytenoideus muscle region. 5. On occasion, the needle may be directed in a straight inferior direction medially through the conus elasticus and the mucous membrane of the subglottic region into the airway lumen (Fig. 7e). This becomes readily apparent as the Teflon paste can be seen to exude into the subglottic lumen. 6. If the needle is directed too far medially into the medial thyroarytenoideus muscle (vocalis muscle), there will be little or no displacement of the vocal cord in a medial direction and the oscillating portion of the cord will become immobilized and greatly interfere with the vocal quality of phonation (Fig. 7f). 7. A fixed arytenoid (cricoarytenoid ankylosis) often cannot be diagnosed until the time of direct laryngoscopy and usage of the spatula test to determine whether or not the arytenoid is mobile and not fixed to the cricoid cartilage. If cricoarytenoid ankvlosis does exist, then a Teflon injection will not be effective, for it is impossible to close the posterior commissure and the air-escape type of hoarseness will persist. 8. A persistent hoarseness will occur even with a successful Teflon injection when weakness of the opposite side of the larynx exists. Preoperatively, it is extremelv difficult to determine whether or not there are myasthenic changes in the opposite vocal cord. Rubin" states that this occurs most frequently in the older male patient.
REFERENCES lytic dysphonia: I. Cartilage injection into a lungsmethode der Rekurrenslahmung. Verh paralysed vocal cord. Arch Otolaryngol 62: 117, 1955 Dtsch Laryngol 18:93-151, 1911 3. Waltner JG: Surgical rehabilitation of 2. Arnold GE: Vocal rehabilitation of para-
1. Briinings W: Uber eine neue Behand-
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14. Dedo HH, Urrea RD, Lawson L: Intracordal injection of Teflon® in the treatment of 135 patients with dysphonia. Ann Otol Rhinol Laryngol 82:661-667, 1973
voice following laryngofissure. Arch Otolaryngol 67 :99-101, 1958 4. Goff WF: Laryngeal adductor raralysis treated by vocal cord injection 0 bone paste: A preliminary investigation. Trans Pac Coast Otoophthalmol Soc 41 :77 -88, 1960
15. Yarington CT Jr, Harned R: Polytef (Teflon) injection for postoperative deglutition problems. Arch Otolaryngol 94:274-275, 1971
5. Arnold GE: Vocal rehabilitation of paralytic dysphonia: VI. Further studies of intracordal injection materials. Arch Otolaryngol 73:290-294, 1961 6. Arnold GE: Vocal rehabilitation of paralytic dysphonia: VIII. Phoniatric methods of vocal compensation. Arch Otolaryngol 76:7683, 1962 7. Lewy RB: Glottic reformation with voice rehabilitation in vocal cord paralysis. Laryngoscope 73:547-555, 1963 8. Rubin HJ: Pitfalls in treatment of dysphonias by intracordal injection of synthetics. Laryngoscope 75: 1381-1395, 1965 9. Arnold GE: Vocal rehabilitation of paralytic dysphonia: IX. Technique of intracordal injection. Arch Otolaryngol 76:358-368, 1962 10. Kirchner FR, Toledo PS, Svoboda DJ: Studies of the larynx after Teflon injection. Arch Otolaryngol 83: 350-354, 1966 11. Stone JW, Arnold GE: Human larynx injected with Teflon paste. Arch Otolaryngol 86:550-561, 1967 12. Rontal E, Rontal M, Morse G, et al: Vocal cord injection in the treatment of acute and chronic aspiration. Laryngoscope 86:625634, 1976 13. Lewy RB: Experience with vocal cord injection. Ann Otol Rhinol Laryngol 85:440450, 1976
16. Rontal E, Rontal M, Rolnick MI: The use of spectrograms in the evaluation of vocal cord injection. Laryngoscope 85:47-56, 1975 17. von Leden J, Yanagihara N, WernerKukuk E: Teflon in unilateral vocal cord paralysis. Arch Otolaryngol 85:666-674, 1967 18. Toomey JM, Brown BS: The histological response to intracordal injection of Teflon paste. Laryngoscope 77: 110-120, 1967 19. Stephens CB, Arnold GE, Stone JW: Larynx injected with polytef paste. Arch Otolaryngol 102:432-435, 1976 20. Boedts D, Roels H, Klugskens P: Laryngeal tissue responses to Teflon. Arch Otolaryngol 86:562-567, 1967 21. Rubin HJ: Misadventures with injectable polytef (Teflon). Arch Otolaryngol 101: 114-116, 1975 22. Lewy RB: Response of laryngeal tissue to granular Teflon's in situ. Arch Otolaryngol 92:355-356, 1970 23. Lewy RB: Tracheotomy avoidance glycerin vocal cord injection. Arch Otolaryngol 92:502-507, 1970 24. Nassar WY: Polytef (Teflon) injection of the vocal cords - experience with 34 cases. J Laryngol Otol 91 :341-347, 1977
REPRINTS - William W. Montgomery, MD, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA 02114.
,... ,...
TENTH INTERNATIONAL CONGRESS ON ACOUSTICS The Tenth International Congress on Acoustics will be held in July, 1980 at the University of New South Wales, Sydney, Australia. The Congress is being sponsored by the Australian Acoustical Society and the Commission on Acoustics (lCA). For further information write: 10 ICA Congress Secretariat, GPO Box 2609, Sydney, NSW Australia 2001.
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LARYNGEAL PARALYSIS TEFLON® INJECTION
WILLIAM W. MONTGOMERY, MD BOSTON, MASSACHUSETTS
This report is a review of the literature combined with the author's experience concerning Teflon injection of the larynx. Included are the etiology and diagnosis of vocal cord paralysis, indications and contraindications for Teflon injection of the larynx, its histopathology, preand postoperative management, proper and improper techniques for injecting Teflon, complications, and reasons for failure.
Unilateral vocal cord paralysis in the partially abducted position (paramedian) can produce a number of distressing symptoms caused by air waste during attempted phonation and inadequate approximation of the cords during swallowing and coughing. In 1911, Brunings,' a German laryngologist, devised a technique of injecting the paralyzed vocal cord with hard paraffin using a syringe of special design. This technique was very successful but later abandoned since the paraffin implant frequently extruded and produced a now well-known complication, paraffinoma. In 1955, Arnold" revived Briinings' technique using autogenous and homogeneous cartilage particles. Subsequently, a number of materials were used: autogenous cartilage graft," heterogeneous bovine bone paste;' tantalum oxide;" Teflon;" tantalum powder," and silicone." Teflon paste (polytef PTFE, Mentor Division of Codman and Shurtleff, Inc., Randolph, MA), a polymer of tetrafluoroethylene, is the most inert of all known plastic materials and has a density of 2.4. The Teflon powder is mixed with glycerin as a vehicle using an equal volume of each substance. The Teflon powder with its small particle size, fulfills all of the criteria for the ideal substance for intracordal injections: 1) it is well tolerated by tissues, 2) it is resorbed in time, 3) it is finely dispersed in a harmless vehicle so that it may be injected through a long needle using the Bruening syringe (Storz Instrument Co., St. Louis, MO.)
During a decade before its use in the larynx, Teflon had proven to be well tolerated by human tissues in thousands of cases of stapedectomy and in its use as an arterial substitute. In 1962, Arnold" published his results from laboratory experimentation with the Teflon-glycerin mixture and also its clinical use for the rehabilitation of paralytic dysphonia. Kirchner et aPO performed experimental studies from 1963 to 1965 using Teflon on the canine larynx for H~ years duration. They demonstrated that there were no carcinogenic effects of Teflon, that Teflon was inert and well tolerated by tissues, Teflon had no necrosing effect on cartilage, and the implant became surrounded by a fibrous capsule. In 1963, Lewy" published a comparative analysis of tantalum-glycerin and Teflon-glycerin mixtures. He found that both mixtures were well-tolerated by the tissues with minimal reaction, that there was no drift of the injected material, and that the situation resulting from the injection was not altered with the passage of time. He also concluded that the Teflon-glycerin mixture was preferred because it is easier to use and can be prepared in advance. Stone and Arnold'" stated after histological studies following Teflon injection in the human, that Teflon was definitely not carcinogenic, there was a minimal foreign body reaction with the Teflon, there was no reaction in the surrounding tissues (both muscle and cartilage), and that the Teflon was surrounded by a fibrous capsule. Thus, by 1966,
From the Department of Otolaryngology, Harvard Medical School and the Massachusetts Eye and Ear Infirmary, Boston. Massachusetts.
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WILLIAM W. MONTGOMERY
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TABLE 1. CAUSES OF VOCAL CORD PARALYSIS13
Cause Head Brain injury Vascular accident Neck Thyroid disease and surgery Trauma Laryngeal surgery Cordectomy Neck surgery Bowed vocal cords Laryngeal Tumor Benign and malignant Carcinoma of the esophagus Chest Lung Benign tumors Malignant tumors Infection Tuberculosis Sarcoidosis Pneumonia Heart enlarged Aortic aneurysm Chest injury Chest surgery Carcinoma of the breast Heart surgery Neurological Parkinson disease Meningitis Metastatic carcinoma Poliomyelitis Other Idiopathic
Estimated % 4
44
30
4
18
polytef had proven to be safe for clinical usage. At that time however, its usage was limited to a relatively small number of laryngologists since the technique of injection was considered difficult, and the selection of cases was thought to require the judgment of an accomplished laryngologist. Teflon-glycerin has now been available for general usage since 1972. ETIOLOGY OF UNILATERAL VOCAL CORD PARALYSIS
Rontal et aJt2 state that approximately 10% of the mown causes of vocal cord paralysis have a central etiology. These include cardiovascular problems, brain abscess, syphilis, Parkinson disease, mul-
TABLE 2. CAUSES OF VOCAL CORD PARALYSIS (N 135)14
=
Cause Surgery: head or neck Malignancy: nasopharynx, neck, chest Idiopathic Traumatic Surgical excision or traumatic loss of cord substance Infections (polio, TB) CVA or brain stem injury Radiation therapy Congenital bilateral bowed mobile cords
No. patients 53 27 29 6 9 3 3 1 4
tiple sclerosis, syringobulbia, medullary tumors, and amyotrophic lateral sclerosis. Peripheral involvement of the recurrent laryngeal nerve probably accounts for the remaining 90%. Of importance is the fact that the left recurrent laryngeal nerve is involved more commonly than the right by a ratio of 10:1. Rontal et al state that lesions of the vagus nerve above the take-off of the superior laryngeal nerve will result in the cords maintaining the intermediate (abducted) position over a long-term period. They state that the recurrent laryngeal nerve section results in the cord gradually returning to the midline position. Lewy'" lists the causes of vocal cord paralysis as in Table 1. He found idiopathic vocal cord paralysis, carcinoma of the lung and thyroid surgery to be the three most common causes for unilateral vocal cord paralysis. Dedo et alB list the causes of vocal cord paralysis as in Table 2. INDICATIONS FOR TEFLON INJECTION
Rontal et aJt2 state that in order to relieve aspiration in acute paralysis following sectioning of the recurrent laryngeal nerve, the vocal cord should be injected as a planned procedure the day following sectioning. They prefer this to Lewy's technique'" using glycerin since the natural history following traumatic section of the recurrent laryngeal nerve is for the affected vocal cords to gradually migrate to the midline. The vocal cord injection, according to Rontal et al, is a benign procedure which can be performed using local anesthesia the day
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6-19
following major surgery with little risk for Teflon injection. In these patients to the patient. The results following there are the following findings: 1) asthese injections are very gratifying since piration, 2) ineffective cough, 3 ) the restoration of cough and prevention breathy hoarseness, 4) poor oxygenation of aspiration allow for a more rapid re- of the blood due to decreased alveolar covery of the patient and often prevents pressure, and 5) inability to laugh. the necessity of a tracheotomy. In patients with aspiration and poor CONTRAINDICATIONS FOR TEFLON phonatory function following subtotal INJECTION laryngectomy, Yarington et al'" state 1. In cases of bilateral vocal cord pathat Teflon injection will relieve this ralysis in the paramedian position," condition and prevent the need for a there is too great a chance for narrowing subsequent total laryngectomy. They the airway and the necessity for an also speculate that Teflon paste would emergency tracheotomy following a Tefnot be well tolerated in those patients lon injection. If a Teflon injection is to who have received radiation therapy. be entertained in such a situation, it Arnold" lists the following indications: should be done along with a trache1. In cases of unilateral vocal cord pa- otomy. ralysis where a) there is hoarseness due 2. Minor defects in the glottic chink to waste of air; b) there is an ineffective should have an attempt for vocal rehacough mechanism; and c) there is de- bilitation by vocal therapy before recreased intra-alveolar pressure; the pro- sorting to a Teflon injection," cedure is indicated. He states that the 3. Injection of Teflon should, as a laryngeal injection of Teflon is indicated mainly in the condition of complete pa- rule, not be attempted for 10 to 12 ralysis of the recurrent laryngeal nerve months following the onset of unilateral with intermediate position of the atro- vocal cord paralysis for the following reasons: a) spontaneous return of funcphic and bowing paralyzed cord. tion with an intact recurrent laryngeal 2. Congenital dysplastic dysphonia is nerve may occur up to 12 months after the result of hypoplasia of the vocalis onset; and b) the paralyzed vocal cord muscle in both sides of the larynx with may gradually migrate to the midline a resultant hypotonic, bowing, vocal position with return of good phonatory cord paralysis. He advises injection first and sphincteric functions. of one vocal cord and, if not effective, 4. Injection of Teflon to improve vocal the opposite cord should be injected as function after a successful arytenoideca separate procedure. tomy is, in my opinion, contraindicated 3. In cases of cordectomy or hemi- because of the possible embarrassment laryngectomy Teflon paste can be used of the laryngeal airway and irreversible to fill the defect and improve phonatory return to a tracheotomy. function as well as preventing aspira5. If it can be determined that psychotion. genic factors" are related to the dys4. Vocal cord defects resulting from phonia, Teflon should not be injected reexcision of benign lesions of the vocal gardless of the clinical picture. Unforcord such as nodules, polyps and papil- tunately however, this diagnosis is very lomas, are indications for the procedure. difficult to establish. 5. Arnold proposed the injection of 6. Arnold" states that cases of incomTeflon to improve vocal function after plete auditory monitoring (or congeniarytenoidectomy. In my opinion, there tal amusia) should not be injected with is too great a risk in this situation for Teflon. embarrassment of the airway and ir7. Rubin" states that myasthenia reversibly returning the patient to a prearytenoid status and a permanent laryngis and hypogenesis vocalis are tracheotomy. contraindications to Teflon injection. Lewy-" lists unilateral vocal cord paralysis as the most common indication
8. Dedo et aP4 also list scar band pseudocord and central nervous system
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lesions where dysphonia is caused by complex dysarthria as contraindications to Teflon injection. DIAGNOSIS
Diagnosis of unilateral vocal cord paralysis in the abducted position can be easily established with indirect laryngoscopy by observing the larynx during inspiration and attempted phonation. The patient may also give a history of aspiration and difficulty with swallowing, especially liquids. By listening to the patient talk, it can easily be determined that the hoarseness is of a breathy type and that he is able to speak a limited number of words following inspiration due to the inefficiency caused by air leakage during phonation. It can also be noted that the patient has a poor cough mechanism and may not be able to laugh. It has become vogue to tape-record the patient's vocal function before and after the Teflon injection. I suspect that this is a fine method for documenting the pre- and postoperative voice for the purpose of teaching. Lewy'" states that voice tapes form a permanent record which is invaluable in evaluating results for legal protection and persuasion. He goes on to say that tapes, however, have a disadvantage as they are not objective. Expert judges vary in the interpretation of changes of voice quality. Eighty-two of Lewy's pre- and postoperative tapes were evaluated and resulted in a subjective analysis of a 60% success rate as compared to his personal estimation of about 90% success. I personally doubt that they would be of value in court and feel that it is unfair to use tape recordings as a method of persuading the patient to agree to the operation. I have found very few patients who are interested in listening to the recordings of their voice. They, and those close to them, evaluate the result of the Teflon injection simply by listening to the voice. Rontal et a)16 advocate voice spectography for analyzing the voice pre- and postoperatively. They state that there are three characteristics identifiable to spectographic analysis that are related to a paralyzed vocal cord: excessive breathiness, aperiodicity of vocal cord
movement, and a breakdown in formant structure. Lewy'" has recorded cough sonograms before and after Teflon injection to demonstrate the improvement in cough effectiveness. Some laryngologists advocate an analysis of the vocal dysfunction by a vocal therapist before and after Teflon injection. This is done so that vocal therapy may be utilized if the degree of voice improvement is not satisfactory following the Teflon injection. I feel that this is a needless expense to the patient and that a vocal therapist can carry out his instruction just as effectively without a preoperative analysis. Von Leden et al," as a research project, studied vocal function pre- and postoperatively by using high speed photography, aerodynamics and acoustic studies. This certainly is not practical in clinical practice. They did however, demonstrate that patients experienced an immediate clinical improvement following Teflon injection and that the functional studies suggest that laryngeal tissues require approximately one month for physiological adaptation to the Teflon implant. mSTOPATHOLOGY OF TEFLON INJECTION
Animal experiments'" in 1966 demonstrated that laryngeal injections of Teflon paste result in an early acute inflammatory response followed by a persistent chronic foreign body reaction. Minimal fibrosis in a fibrous capsule surrounds the implant. The original volume and position of implants are well maintained both because the glycerin is replaced volumetrically by a cellular infiltrate and because the 50-100 micro-Teflon particles are larger than the local lymphatics. Teflon is well tolerated by tissues because of its chemical inertness and insolubility, and because it is nonantigenic. Stephens et a}19 describe the pathology as a foreign body reaction with giant cells, few lymphocytes, and no polymorphonuclear leukocytes during the early stage and later, a bland reaction of a chronic type with a fibrous capsule and advancing fibrosis. In no instance did they find any evidence of carcinogenicity. Boedts et al 2 0 reported the results of
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canine experiments in 1967. These experiments demonstrated the stability of Teflon paste even after two years following the injection. The Teflon was found to be inert chemically and well tolerated. They found no mechanical migration of the Teflon implant. The Teflon caused no necrosis of laryngeal cartilage and there was no evidence of carcinogenic effects. It is of note that Teflon particles were found adjacent to and in lymphatics and small blood vessels. There was however, no evidence of spread of Teflon beyond the confines of the larynx or to distant parts of the body. Kirchner et al l o in canine experiments performed from 1963-1965, demonstrated that Teflon-glycerin mixture was effective in displacing a paralyzed vocal cord medially and that there was no carcinogenic effect. They also found Teflon to be inert, well tolerated by tissues, that it did not produce necrosis of cartilage and that the implant became surrounded by a fibrous capsule. Lewy's study of the pathology of intralaryngeal injection of Teflon paste performed in 1966 demonstrated that the mild inflammatory reaction was replaced by a fibrous capsule formed around the Teflon paste which had been injected, that there was no evidence of carcinogenicity. Stone and Arnold'! demonstrated in 1966 that Teflon produced a foreign body reaction which was surrounded by a fibrous capsule. These studies indicated that Teflon was not carcinogenic. PREOPERATIVE INFORMATION FOR THE PATIENT
Preoperatively, the patient should be told why he is experiencing a breathy hoarseness, aspiration and an ineffective cough. The patient is informed that the procedure involves a direct laryngoscopy, ie, the introduction of an illuminated metal tube into the throat. During the procedure, a needle, which is attached to a pressure syringe similar to a caulking gun, is introduced through the laryngoscope and into the tissues outside the paralyzed vocal cord. The bulk of the implant causes the paralyzed vocal cord to be moved in the direction of the opposite functioning vocal cord. This
651
enables the functioning cord to strike against the paralyzed cord, thereby improving the voice and cough and preventing aspiration. It is explained to the patient that there is approximately an 80% chance for improvement and a slight chance that the condition might worsen. The main reason for failure is that it is difficult to control the exact positioning of the Teflon paste in the tissues and, in some instances, the Teflon drifts to adjacent tissues as it is being injected. The patient should also be informed that there is a possibility for failure and complication as there can be with any operation and anesthesia. TECHNIQUE OF ANESTHESIA
The anterior floor of mouth, pharynx and larynx are anesthetized with 4% cocaine solution. Two cubic centimeters of Xylocaine® solution without epinephrine are injected just below the tip of the greater horn of the hyoid bone on each side in the region of the thyrohyoid membrane. This will provide excellent anesthesia of both superior laryngeal nerves. Two cubic centimeters of 4% cocaine solution are injected into the cervical trachea. The anesthesiologist then injects 1 cc of Inovar® solution intravenously. After approximately 15 minutes additional Inovar is administered until the patient nears general anesthesia but will still respond to requests to phonate. The patient must, of course, be encouraged to take deep breaths during this period. TECHNIQUE OF TEFLON INJECTION
The patient is placed in the position for direct laryngoscopy and an anterior commissure laryngoscope is introduced. If elevation of the epiglottis is painful, produces gagging, or a laryngospasm, then additional 4% cocaine solution is sprayed directly through the laryngoscope. A laryngeal needle with a 19 or 20 gauge tip is used along with a Bruening syringe (Fig. 1). The Bruening syringe must be promptly loaded and tested immediately prior to injection in order to assure that the Teflon flow is smooth (Figs. 15). Teflon paste must not be introduced into the syringe the day prior to its us-
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WILLIAM W. MONTGOMERY
Fig. 1. Photograph of the ArnoldBruening intralaryngeal Teflon injection set.
age since the result will be either underor overinjection of Teflon. Both the needle and the Bruening syringe must be carefully cleaned after their usage with ethyl alcohol. Some practice is required in order to accomplish expertise with the Bruening syringe. Teflon continues to flow from the needle tip after each click and there is no method to determine the exact amount being injected other than to keep a careful eye on the cord being injected. It is also essential that the site of the injection be clearly visible as the Teflon paste is being injected. Simultaneously, the patient should phonate gently on command so that the proper end point can be established. As soon as
Fig. 3. The needle is screwed onto the loading chamber and tightened with the wrench. Continued squeezing of the tube will force Teflon paste into the needle.
the end point of voice return is reached, the injection should be immediately ceased. The laryngeal needle is introduced through the anterior commissure laryngoscope so that its tip is at the level of the true vocal cord. The bevel of the needle tip should be facing medially
Fig. 4. The tube and loading adaptor are removed from the loading chamber when a smooth continuous ribbon of paste emerges from the tip of the needle.
( Fig. 6a). The tip of the needle is moved laterally over the superior surface of the paralyzed vocal cord until it displaces the false cord slightly in a lateral direction (Fig. 6b). With the needle in an oblique lateral direction, it
Fig. 2. The cap is removed from the tube which contains 7 cc of Teflon paste. After puncturing the seal of the tube, the loading adaptor is screwed onto the tip of the Teflon paste tube. The loading adaptor is inserted into the proximal end of the loading chamber. The end of the Teflon paste tube is rolled up and the tube squeezed with one hand as the loadingchamber is held in the other. It takes considerable pressure and a few minutes to fill the loading chamber.
Fig. 5. The loading chamber is attached to the handle of the syringe and tightened with a wrench.
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LARYNGEAL PARALYSIS , I
Thyroid cartilage Folse vocal Laryngeal ventricle
Lot thyroarytenoid m. Med. thyroarytenoid m. (vacalis rn.)
~~I--_ Conus
elasticus
Lot. cricoarytenoid m. Cricat hyroid m. CricOid cartilage
(b)
(0)
Porolyred side
Functioning side
Teflon injection advancing true card to midline
(d)
(c)
Dolled lines simulate adduction of functioning cord
Fig. 6. a) The needle is introduced through an anterior commissure laryngoscope to the upper medial margin of the midligamentous vocal cord. b) The tip of the needle is then moved laterally so as to displace the false vocal cord laterally and advanced to the lateral aspect of the laryngeal ventricle. c) The needle (size 18 or 19) is introduced into the lateral aspect of the lateral thyroarytenoid muscle. The depth of this injection depends on the size of the larynx, ie, the depth in a small female larynx may be 3 mm and a large male larynx 5 mm, The depth can be estimated by remembering that the total length of the needle tip is 14 mm. d) Approximately 0.3 to 1.0 ml of Teflon paste is needed to reach the end point which is approximation of the ligamentous cords during phonation. Each click of the Bruening syringe delivers about 0.2 ml of Teflon paste providing time is allowed for compression and dissipation of the paste. There should thus be a delay of about 15 seconds between clicks. It is possible to deliver about 1.6 ml of Teflon paste with one loading of the Bruening syringe. The actual amount of Teflon retained in the tissue, of course, depends on the amount which exudes from the mucosal puncture site after the needle is removed. A second injection is usually required into the lateral thyroarytenoideus muscle at a point along the vocal cord easily identified by the tip of the vocal process medially so that the posterior commissure can be closed during phonation.
is advanced through the floor of the ventricle and into the substance of the lateral thyroarytenoid muscle (Fig. 6c). The first injection is made midway be-
tween the anterior commissure and the vocal process of the arytenoid. This injection is continued until the patient can approximate the opposite cord against
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(e)
(0
Fig. 7. a) Some Teflon injection needles come with a cuff or guard placed 4.5 mm from the end of the needle tip. (See text for details.) b) Coronal section of the larynx through the midligamentous portion of the vocal cord. The needle injection is shallow. Teflon will be deposited submucosally and result in obliteration of the laryngeal ventricle and no medial displacement of the vocal cord. c) Injection is in the proper direction but too deep. Teflon paste will be deposited in the lateral cricothyroid muscle or through the cricothyroid space and outside the larynx. In such cases, a mass may be palpated in the neck. d) The needle is placed too medially and deeply between the mucosa and the conus elasticus. This injection will result in a subglottic bulge. e) The needle is directed too medially and deeply and the tip penetrates the subglottic mucous membrane. As Teflon paste is injected, it can be visualized entering the subglottic lumen. f) The needle is introduced into the medial thyroarytenoideus. This infiltrates the vocalis portion of the thyroarytenoideus muscle and serves only to immobilize this area rather than displace the vocal cord medially.
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LARYNGEAL PARALYSIS
the side being injected while phonating (Fig.6d). Some authors advocate the use of a needle guard to prevent advancing the needle beyond a depth of 4.5 mm. The ideal depth in any particular case however, will vary with the size of the larynx. Also, the needle guard may give a false sense of security in that injections far beyond a depth of 4.5 mm can result as the needle guard indents the mucous membrane of the laryngeal ventricle (Fig. 7a). The amount of Teflon paste necessary will, of course, vary with the size of the larynx and the degree of lateral displacement of the paralyzed vocal cord. It is best to err on the side of underiniection rather than overinjection for Teflon, once injected, is difficult to remove. The needle should remain in place as long as possible following the injection. This will minimize the amount of Teflon paste lost since some Teflon paste exudes from the puncture in the mucous membrane after the needle is removed. On occasion, one injection is sufficient to restore good phonatory function. A second injection, however, is usually necessary. This is accomplished just lateral to the anterior aspect of the vocal process of the arytenoid and serves to close the posterior commissure. Again, it is difficult to estimate the amount of Teflon used in any given case as the Bruening syringe is not calibrated, some Teflon continues to flow from the tip of the needle after it is removed, and a varying amount of Teflon paste exudes from the needle puncture site after the needle is removed. An estimate of 1.00-1.50 cc of Teflon probably means that 0.75-1.00 cc of Teflon paste was actually retained in the tissues. It was earlier thought that the Teflon injection remamed as an encapsulated mass restricted to the region of the lateral thyroarytenoideus muscle. A number of histopathology reports are now in the literature.8 , l1 , 1 5 ,1 9 , 21 These studies demonstrate that Teflon paste often extends into the lateral cricoarytenoideus muscle and also through the cricothyroid space and even extralaryngeallv. This, for the most part, has not been clinicallv significant in that there was very good
655
rehabilitation of the laryngeal disorder in each case and there were no complicating signs and symptoms, except in one case where the extralaryngeal mass was misinterpreted as a thyroid nodule. It is thus obvious that a certain amount of drift and misplacement of the Teflon paste will occur regardless of the technique and skill of the surgeon. POSTOPERATIVE COURSE
As a general rule, the patient will complain of postoperative pain localized to the side of the larynx injected. This is especially true when it has been necessary to inject lateral to the vocal process of the arytenoid in order to close the posterior commissure. By indirect laryngoscopy, it can be observed the following day that the injected vocal cord is usually swollen. The mucous membrane of the laryngeal ventricle is also edematous and may be slightly prolapsed. The postoperative vocal function will gradually improve over a two to four-week period until it reaches its level of permanent improvement. Complications 1. Swelling may occur as a reaction to the Teflon injection. I feel that it is wise to administer 6-8 mg of Decadron® intraoperatively and at the end of two 6hour periods in order to prevent postoperative edema resulting from the reaction to the injection. A number of investigators have reported respiratory distress and stridor occurring within 24 hours after the iniection. 8 , 1 3, 1 5 , 21 , U Patients were successfully treated by using intravenous cortisone, ampicillin and steam inhalations. A number of cases of severe edema have been reported, necessitating a temporary tracheotomy. In all cases the edema gradually subsided and the tracheotomy was removed. This complication however, can usually be avoided by using cortisone before and after the implantation of the Teflon. 2. Pain, which usually subsides in about a week, may persist for many weeks. 3. Expectoration of Teflon particles or blood-tinged saliva may Occur during the first one or two postoperative days and should not disturb the patient.
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4. Granuloma formation at the site of the injection is a slight possibility. This can be removed by way of laryngoscopy and its recurrence prevented by injecting cortisone into the region of the implant. POSSIBLE REASONS FOR FAILURE FOLLOWING TEFLON INJECTION
1. Improper intracordal placement of Teflon can result in failure. The ideal situation for placement of Teflon is in the lateral thyroarytenoideus muscle as is shown in Figure 6d. The injection into the lateral aspect of the thyroarytenoideus muscle produces a shift of the muscle in a medial direction with minimal infiltration of the oscillating portion of the cord. It is not uncommon however, for the Teflon to migrate towards and into the false vocal cord, into the lateral cricoarytenoideus muscle and even extralaryngeally during the Teflon injection. As long as the Teflon paste does not infiltrate the oscillating portion of the vocal cord, these latter extensions of Teflon paste do not seem to interfere with a good result.
2. If the needle is placed too superficially (Fig. 7b), the needle tends to infiltrate the submucosal space of the larvngeal ventricle and obliterate it rather than infiltrate the lateral thyroarytenoideus muscle. Usually, this type of injection can be readily observed as it occurs and can be corrected by inserting the needle to a greater depth. 3. If the needle is directed at the proper angle into the cricoarytenoid space, the Teflon will occupy the cricothyroid and lateral cricoarytenoideus muscle (Fig. 7c) and may even escape extralarvngeally to the neck. This does very little in causing a medial disnlacement of the paralyzed vocal cord. When this type of injection occurs and there is no perceptible shift of the vocal cord in a medial direction, there mayor may not appear a bulge immediatelv beneath the level of the vocal cords. The situation can be corrected by withdrawing the
needle into the lateral thyroarytenoideus muscle and injecting an additional small amount of Teflon paste. 4. If the needle is directed in a straight inferior direction rather than an oblique lateral direction, and does not penetrate to the conus elasticus muscle, there will appear a very obvious bulge in the immediate subglottic region (Fig. 7 d). When this occurs, the needle shonld be withdrawn and directed laterally into the lateral thyroarytenoideus muscle region. 5. On occasion, the needle may be directed in a straight inferior direction medially through the conus elasticus and the mucous membrane of the subglottic region into the airway lumen (Fig. 7e). This becomes readily apparent as the Teflon paste can be seen to exude into the subglottic lumen. 6. If the needle is directed too far medially into the medial thyroarytenoideus muscle (vocalis muscle), there will be little or no displacement of the vocal cord in a medial direction and the oscillating portion of the cord will become immobilized and greatly interfere with the vocal quality of phonation (Fig. 7f). 7. A fixed arytenoid (cricoarytenoid ankylosis) often cannot be diagnosed until the time of direct laryngoscopy and usage of the spatula test to determine whether or not the arytenoid is mobile and not fixed to the cricoid cartilage. If cricoarytenoid ankvlosis does exist, then a Teflon injection will not be effective, for it is impossible to close the posterior commissure and the air-escape type of hoarseness will persist. 8. A persistent hoarseness will occur even with a successful Teflon injection when weakness of the opposite side of the larynx exists. Preoperatively, it is extremelv difficult to determine whether or not there are myasthenic changes in the opposite vocal cord. Rubin" states that this occurs most frequently in the older male patient.
REFERENCES lytic dysphonia: I. Cartilage injection into a lungsmethode der Rekurrenslahmung. Verh paralysed vocal cord. Arch Otolaryngol 62: 117, 1955 Dtsch Laryngol 18:93-151, 1911 3. Waltner JG: Surgical rehabilitation of 2. Arnold GE: Vocal rehabilitation of para-
1. Briinings W: Uber eine neue Behand-
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LARYNGEAL PARALYSIS
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14. Dedo HH, Urrea RD, Lawson L: Intracordal injection of Teflon® in the treatment of 135 patients with dysphonia. Ann Otol Rhinol Laryngol 82:661-667, 1973
voice following laryngofissure. Arch Otolaryngol 67 :99-101, 1958 4. Goff WF: Laryngeal adductor raralysis treated by vocal cord injection 0 bone paste: A preliminary investigation. Trans Pac Coast Otoophthalmol Soc 41 :77 -88, 1960
15. Yarington CT Jr, Harned R: Polytef (Teflon) injection for postoperative deglutition problems. Arch Otolaryngol 94:274-275, 1971
5. Arnold GE: Vocal rehabilitation of paralytic dysphonia: VI. Further studies of intracordal injection materials. Arch Otolaryngol 73:290-294, 1961 6. Arnold GE: Vocal rehabilitation of paralytic dysphonia: VIII. Phoniatric methods of vocal compensation. Arch Otolaryngol 76:7683, 1962 7. Lewy RB: Glottic reformation with voice rehabilitation in vocal cord paralysis. Laryngoscope 73:547-555, 1963 8. Rubin HJ: Pitfalls in treatment of dysphonias by intracordal injection of synthetics. Laryngoscope 75: 1381-1395, 1965 9. Arnold GE: Vocal rehabilitation of paralytic dysphonia: IX. Technique of intracordal injection. Arch Otolaryngol 76:358-368, 1962 10. Kirchner FR, Toledo PS, Svoboda DJ: Studies of the larynx after Teflon injection. Arch Otolaryngol 83: 350-354, 1966 11. Stone JW, Arnold GE: Human larynx injected with Teflon paste. Arch Otolaryngol 86:550-561, 1967 12. Rontal E, Rontal M, Morse G, et al: Vocal cord injection in the treatment of acute and chronic aspiration. Laryngoscope 86:625634, 1976 13. Lewy RB: Experience with vocal cord injection. Ann Otol Rhinol Laryngol 85:440450, 1976
16. Rontal E, Rontal M, Rolnick MI: The use of spectrograms in the evaluation of vocal cord injection. Laryngoscope 85:47-56, 1975 17. von Leden J, Yanagihara N, WernerKukuk E: Teflon in unilateral vocal cord paralysis. Arch Otolaryngol 85:666-674, 1967 18. Toomey JM, Brown BS: The histological response to intracordal injection of Teflon paste. Laryngoscope 77: 110-120, 1967 19. Stephens CB, Arnold GE, Stone JW: Larynx injected with polytef paste. Arch Otolaryngol 102:432-435, 1976 20. Boedts D, Roels H, Klugskens P: Laryngeal tissue responses to Teflon. Arch Otolaryngol 86:562-567, 1967 21. Rubin HJ: Misadventures with injectable polytef (Teflon). Arch Otolaryngol 101: 114-116, 1975 22. Lewy RB: Response of laryngeal tissue to granular Teflon's in situ. Arch Otolaryngol 92:355-356, 1970 23. Lewy RB: Tracheotomy avoidance glycerin vocal cord injection. Arch Otolaryngol 92:502-507, 1970 24. Nassar WY: Polytef (Teflon) injection of the vocal cords - experience with 34 cases. J Laryngol Otol 91 :341-347, 1977
REPRINTS - William W. Montgomery, MD, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA 02114.
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TENTH INTERNATIONAL CONGRESS ON ACOUSTICS The Tenth International Congress on Acoustics will be held in July, 1980 at the University of New South Wales, Sydney, Australia. The Congress is being sponsored by the Australian Acoustical Society and the Commission on Acoustics (lCA). For further information write: 10 ICA Congress Secretariat, GPO Box 2609, Sydney, NSW Australia 2001.
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