Minifenestration Type I Thyroplasty Using an Expanded Polytetrafluoroethylene Implant

Journal of Voice Vol. 15, No. 1, pp. 151–157 © 2001 The Voice Foundation

Minifenestration Type I Thyroplasty Using an Expanded Polytetrafluoroethylene Implant C. Richard Stasney, Mary Es Beaver, and Margarita Rodriguez Texas Voice Center, Houston, Texas; Baylor College of Medicine, Houston, Texas

Summary: Several methods have been used to treat laryngeal incompetence, but no ideal technique has been identified. This paper describes a clinical experience with minifenestration type I thyroplasty using a new device made of expanded polytetrafluoroethylene (ePTFE). The device, a thin ribbon of ePTFE, is inserted through a 4-mm fenestration to produce vocal fold medialization. At our center, 26 of these devices have been implanted in the past 3 years. Good or satisfactory results were achieved in 96% of cases. Advantages of this technique include easy insertion of the implant, nominal cost and biocompatibility of the ePTFE device, ready availability of all instruments required for the procedure, and elimination of the need to perform arytenoid adduction. Key Words: Laryngeal paralysis—Thyroplasty—Vocal fold medialization—Expanded polytetrafluoroethylene.

Type I thyroplasty (vocal fold medialization), which was popularized by Isshiki,10 is the most widely used operation for treating laryngeal incompetence. Several variations of this procedure have been described, but most involve insertion of an implant through a window in the thyroid cartilage. A number of implant materials have been used for this purpose, including silicone,11,12 hydroxylapatite,13 titanium,14 and expanded polytetrafluoroethylene (ePTFE).15,16 Each material has its advocates, but none has been found to be superior to the others. We used carved silicone blocks for thyroplasty implants for several years,11 beginning in the early 1990s, with moderate success. However, problems with implant extrusion reported in the literature,17 as well as the difficulty involved in carving, inserting, and stabilizing the silicone, led us to search for alternative prostheses. At the suggestion of heart surgeons at our center, we began to use cut ePTFE cardiovascular patches for thyroplasty. Others are beginning to use this material. Giovanni et al.15 and McCulloch and Hoffman,16 for example, used strips of ePTFE

INTRODUCTION Incompetence or paralysis of the larynx resulting from neuropathy, presbylaryngis, iatrogenic injury, or other causes represents a considerable therapeutic challenge. Many techniques to effect closure of the larynx and thereby improve the voice have been reported. Injection laryngoplasty procedures using Teflon paste,1,2 collagen,3,4 fat injection,5,6 or other substances have been employed for several years, but success has not always been achieved. Collagen and fat may be resorbed over time, whereas Teflon, the most commonly used material, may produce local inflammatory or granulomatous reactions2,7 that are very difficult to treat.8,9 Therefore, various surgical procedures have been developed to address the problem of glottal incompetence. Accepted for publication August 20, 2000. Address correspondence and reprint requests to C. Richard Stasney, Texas ENT Consultants, 6550 Fannin, Suite 2001, Houston, TX, 77030 USA. This paper was presented at the 29th Voice Foundation Symposium, Philadelphia, Pennsylvania, July 2, 2000.

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cut from cardiovascular patch material in series of 16 and 13 patients, respectively. Voice results were good or satisfactory, and there were no complications except for one extrusion in the series of Giovanni et al.15 Recently, an ePTFE device designed especially for use in type I thyroplasty became available (Gore Thyroplasty Device, WL Gore & Associates, Flagstaff, AZ). Use of this device, which consists of a 0.6mm-thick ribbon of ePTFE supplied in several different length-and-width configurations, eliminates the need to fashion the ePTFE implant from a cardiovascular patch. Here we describe our clinical experience with this device in 26 patients. METHODS Patients The records of all patients who underwent minifenestration type I thyroplasty using an ePTFE thyroplasty device at our center between February 1997 and April 1, 2000 were reviewed, and patient demographic, operative experience, and outcome data were compiled. The mean patient age was 58.2 (34–78) and male/female ratio was 1:1.6. The left vocal fold was affected in 22 cases, and the right vocal fold was affected in 4 cases. Patient characteristics, including the cause of the voice problem and any previous therapy, are shown in Tables 1 and 2. Assessments All patients underwent videostroboscopy, computerized voice analysis, and pulmonary function testing before the surgical procedure. Patients were scheduled for repeat videostroboscopy at 1, 3, and 6 weeks, and 6 months after the procedure and for computerized voice analysis and airflow assessment at least once after the operation. Postoperative voice results were graded as I (good voice), II (fair voice, slightly breathy), or III (poor voice, very breathy). Acoustic parameters studied included percent jitter and percent shimmer. Airflow measurements studied included maximum phonation time (MPT) for the spoken vowel /a/ and /i/ and the s/z ratio (Table 3). Surgical technique Preoperatively, the defect is measured meticulously with use of videostroboscopy, and its location (anterior, middle, or posterior membranous vocal fold) and the degree of closure in the interarytenoid area Journal of Voice, Vol. 15, No. 1, 2001

TABLE 1. Characteristics of 24 Patients Who Underwent Minifenestration Type I ePTFE Thyroplasty Etiology

N(26)

Idiopathic

6

Aortic aneurysm

2

Thyroidectomy

3

Laryngeal fracture

1

Left pneumonectomy

1

Gastric pull for esophageal cancer

1

Congenital

1

Acoustic neuroma

1

Abdominal surgery

1

Left carotid endarterectomy

2

Aortic arch repair

1

Congenital malformation

1

Lung cancer

1

Trauma

1

Facial plastic surgery

1

Coronary artery bypass grafting

1

Cervical spinal fusion

1

TABLE 2. Previous Therapy for Voice Previous Therapy

N (8)

Speech therapy

4

Thyroplasty

1

Fat injection

2

Gelfoam® injection

1

TABLE 3. Voice Results* Voice Result

N (26)

%

Grade I

18

69

Grade II

7

27

Grade III

1

4

*Grade

I = good voice; Grade II = Satisfactory voice or slightly breathy; Grade III = poor voice or very breathy.

MINIFENESTRATION TYPE I THYROPLASTY are determined. An analogue version of the videostroboscopic data is brought to the operating suite and reviewed before and during the procedure. The patient is lightly sedated, transported to the operating suite, and placed in the supine position under monitored local anesthesia. The neck is prepared and draped so that there is access to the thyroid area but the face is uncovered. Usually, three towel drapes are placed inferiorly and an adhesive towel drape is used to cover the patient’s mandible to separate the surgical area and decrease the risk of fire from cautery if the patient is receiving nasally administered oxygen supplementation. Local anesthesia is obtained by infiltration of lidocaine with epinephrine (1:100,000). In some cases, patients are also given a small dose of intravenous propofol immediately before the first injection of anesthetic agents into the neck. An incision of approximately 7 cm is made over the midthyroid cartilage, eccentrically located toward the side of the defect, and flaps are raised superiorly and inferiorly. The strap muscles are divided in the midline, and the thyroid cartilage is skeletonized. Elevation of the cricothyroid muscle on the defect side is done with special care to ensure that it is damaged as little as possible; a Freer elevator, blunt elevation technique, and minimal use of cautery are useful in this regard. After the thyroid cartilage has been exposed, calipers are used to measure the distance from the superior to the inferior aspect of the thyroid cartilage in the midline (usually this is about 22 mm). The halfway point of this distance marks the location on the anterior thyroid cartilage where the vocal ligament attaches. A posteriorly based apron flap of perichondrium is then raised over most of the lateral and inferior thyroid cartilage. After elevation of the flap, a window is outlined with methylene blue to mark the rough projection of the vocal fold on the lateral thyroid cartilage. This window is about 4  9 mm in women and 5  10 mm in men (Figures 1–3). With this window used as a guide (and teaching tool), a 4-mm burr is employed to drill a single hole through the cartilage in a posterior, middle, or anterior location, depending on the location of the defect. If the cartilage is soft and noncalcified, a round knife and flap knife may be used together to create this minifenestration. The inner cartilage edge is removed with a stapes curette, and the inner perichondrium is elevated for

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approximately 3 mm in all directions with a round knife. The inner perichondrium is then depressed with a round knife (or cleoid) for a few millimeters in all directions to ascertain which location provides the best voice quality. This procedure should be limited to about 5 minutes to avoid excessive edema of the affected vocal fold. The patient is asked to hold an “A” vowel for as long as possible before and after various locations in the inner perichondrium are depressed with a blunt instrument (e.g., Cleoid, Cottle elevator, or gimmick). When the voice quality improves noticeably and the maximum phonation time has at least doubled, the location and degree of depression of the round knife at that point are what

FIGURE 1. The rectangle marks the typical location for an Isshiki window in a small larynx (female patient); it is about 4  9 mm. The circle in the middle of the rectangle is the 4-mm diameter site for drilling a minifenestration for implantation of an ePTFE thyroplasty device in a patient with a centrally located defect in the vocal fold. Journal of Voice, Vol. 15, No. 1, 2001

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FIGURE 2. Two views of a minifenestration created in the lateral right thyroid cartilage for insertion of an ePTFE thyroplasty device.

FIGURE 3. Location of hole in posterior thyroid cartilage allowing insertion of Gore-Tex® implant (even placing over cricoid) for vocal process medialization. Journal of Voice, Vol. 15, No. 1, 2001

must be duplicated permanently by implantation of the ePTFE thyroplasty device. For the implantation procedure, one small hole is drilled above the minifenestration and one is drilled below it with a very fine drill bit. Then, 4-0 monofilament nylon suture is inserted into the holes for subsequent attachment of the ePTFE device. The implant may be immersed in an antibiotic solution before insertion, but this is probably unnecessary because the device is supplied sterile, the procedure is sterile, and the patient is usually given antibiotics perioperatively. The ePTFE thyroplasty device is then inserted into the minifenestration by folding it in with a micro alligator and an annulus elevator (“gimmick”). Each fold of material is 1.2-mm thick (since the material itself is 0.6-mm thick), so folding provides an approximate measurement of the depression to be achieved (especially when the deficit has been measured preoperatively on a videostrobolaryngogram). It is important to insert enough material to achieve a sufficient prolongation in MPT; this measurement provides an additional way to assess improvement of the patient’s voice in the operating room. After enough ePTFE material has been inserted, it is anchored to the thyroid cartilage with the nylon sutures superiorly and inferiorly, the outer perichondri-

MINIFENESTRATION TYPE I THYROPLASTY um is sutured in place, the strap muscles are approximated, and the skin incision is closed. A small drain is inserted and a light compression dressing applied. The patient remains in the hospital for 24 hours with a drain to suction, airway monitoring, voice rest, and head elevated 30°. The patient is allowed to talk when the drain is removed the following morning, and discharged home with pain medication and a firstgeneration cephalosporin for 5 days. RESULTS Twenty-six thyroplasty operations using the ePTFE device were performed at our center between February 1997 and April 1, 2000. There were no cases of abnormal bleeding, airway compromise, or infection. All patients were discharged from the hospital within 24 hours. All cases were assessed preoperatively and postoperatively with videostroboscopy. Preoperative and postoperative computerized voice analysis results were available for 15 patients; preoperative and postoperative airflow assessment was available for 18 patients. Six additional patients were contacted by phone and their voice quality assessed by a speech and language pathologist (SM). Eighteen patients (69%) had a grade I voice postoperatively, 7 (27%) had a grade II voice result, and 1 (4%) had a grade III result (Table 3). Acoustic measurements were analyzed using Sigma Plot Scientific Solutions (SPSS) statistical software (SPSS Science Corp., Chicago, IL). Maximum phonation time improved in 96% of cases, with all improvements in mean postoperative MPT/a/, MPT/i/, jitter, and shimmer being statistically significant on paired Student’s t-test (Table 4). The patient with the poor result was a 78-year-old woman with a severe associated neuropathy. PostopTABLE 4. Acoustic Characteristics of Voices Preoperatively and Postoperatively MPT /a/

MPT /i/

%Jit

%Shim

Mean Preop

8.29

8.10

4.77

9.40

Mean Postop

12.74

13.09

P value*

0.006

0.019

2.31

5.05

0.008

0.055

Abbreviations: MPT = maximum phonation time; %Jit = percent jitter; %Shim = percent shimmer. *Statistical significance set as P < 0.05 using paired t-test.

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erative videostroboscopy demonstrated good vocal fold closure, but the patient had considerable tremor and some dysarthria. In another patient, who underwent surgery before we routinely sutured the ePTFE implant in place, the voice was excellent for the first 6 weeks after surgery and then gradually declined in quality. Two months after the procedure, videostroboscopy showed recurrence of incompetent larynx. An exploratory operation on the neck was done, and the ePTFE implant was found to have extruded from the minifenestration. The implant was easily removed with a second procedure, and a second implant was inserted and sutured in place. The patient has had no other problems and has maintained a satisfactory voice for 2 years. DISCUSSION In our series of 24 patients in whom a new ePTFE thyroplasty device was used in a minifenestration surgical procedure to treat laryngeal incompetence, we found the operation to be safe and effective. No operative complications occurred, and postoperative voice quality was good or satisfactory in all but one patient. Only one extrusion occurred. This apparently resulted from our failure to suture the ePTFE implant in place. Subsequently, all implants, including the one inserted to replace the implant that extruded, were sutured. Our extrusion rate of 4% and our satisfactory voice improvement rate of 96% compare favorably with the rates of 5.4% and 90%, respectively, reported in a 1998 survey of more than 14,000 medialization laryngoplasties.18 Moreover, our results using ePTFE, like those of Giovanni et al.15 and McCulloch and Hoffman,16 may be better than outcomes achieved with silicone-block implants. For example, in one large series (60 patients),17 siliconeblock phonosurgery was followed by six obstructive hematomas and four extrusions, including two in which the implant was coughed out spontaneously. Cotter et al.19 (50 patients) had a hematoma rate of 24% and an extrusion rate of 9.8%. On the other hand, no extrusions were reported in a series of 116 silicone medialization procedures described by Netterville et al.20 Our clinical experience suggests several advantages of minifenestration ePTFE type I thyroplasty. First, the implant procedure requires only instruments already available in most otolaryngology opJournal of Voice, Vol. 15, No. 1, 2001

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erating rooms. As a result, no new allocation of funds for equipment is required before this operation can begin to be performed at a center. Second, the ribbonlike ePTFE implant can be inserted medially to the vocal process of the arytenoid by snaking it up over the cricoid, thereby allowing large posterior defects to be medialized without performing a second procedure, that is, the arytenoid adduction technique described by Isshiki et al.21 and others.22 This is not possible with hard implant materials, such as those made of silicone or titanium. Avoidance of the arytenoid adduction procedure will save patient and operating-room time and costs, and prevent the potentially life-threatening complications that can result from inadvertent entry into the pyriform sinus during arytenoid adduction. Third, the new ePTFE thyroplasty device we used, unlike the ePTFE materials previously employed in thyroplasty, is available precut in several length and width configurations. Any necessary modifications to the device can be made easily before it is sutured in place, but both the time previously spent cutting strips of ePTFE from cardiovascular patch material and the cost of an entire patch are saved. Moreover, the uniform thickness of the thyroplasty device (0.6 mm) provides an operative guide for estimating the defect area that must be filled to improve voice quality. Finally, ePTFE has been used for more than 30 years in numerous surgical applications, including facial plastic surgery, and has been found to be inert and to rarely extrude.23 The porous nature of the material allows some tissue attachment, but it remains relatively easy to remove, if necessary, as we found in this series. In addition, the presence of ePTFE does not preclude use of other therapies: in patients in whom minor gaps remain after the material has been implanted, fat injection can be used to enhance voice results. CONCLUSIONS Minifenestration ePTFE type I thyroplasty is a safe and effective procedure for amelioration of glottal incompetence. The technique is easy to perform, it can be done with readily available instruments, and it provides good or satisfactory voice results in most patients. The ePTFE implant used is biocompatible and relatively inexpensive, and it adapts easily to a Journal of Voice, Vol. 15, No. 1, 2001

variety of glottal gaps. Revisions and augmentation with fat are possible when voice results are not satisfactory. Acknowledgments: We would like to thank Sally McKee, M.A., CCC, for her assistance in patient assessment.

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MINIFENESTRATION TYPE I THYROPLASTY 16. McCulloch TM, Hoffman HT. Medialization laryngoplasty with expanded polytetrafluoroethylene: surgical technique and preliminary results. Ann Otol Rhinol Laryngol. 1998; 107:427-432. 17. Tucker HM, Wanamaker J, Trott M, Hicks D. Complications of laryngeal framework surgery (phonosurgery). Laryngoscope. 1993;103:525-528. 18. Rosen CA. Complications of phonosurgery: results of a national survey. Laryngoscope. 1998;108:1697-1703. 19. Cotter CS, Avidano MA, Crary MA, Cassisi NJ, Gorham MM. Laryngeal complications after type I thyroplasty. Otolaryngol Head Neck Surg. 1995;113:671-673. 20. Netterville JL, Stone RE, Luken ES, Civantos FJ, Ossoff

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RH. Silastic medialization and arytenoid adduction: the Vanderbilt experience. A review of 116 phonosurgical procedures. Ann Otol Rhinol Laryngol. 1993;102:413-424. 21. Isshiki N, Tanabe M, Sawada M. Arytenoid adduction for unilateral vocal cord paralysis. Arch Otolaryngol. 1978; 104:555-558. 22. Kraus DH, Orlikoff RF, Rizk SS, Rosenberg DB. Arytenoid adduction as an adjunct to type I thyroplasty for unilateral vocal cord paralysis. Head Neck. 1999;21:52-59. 23. Campbell A, Shumrick KA. The use of expanded polytetrafluoroethylene in facial reconstruction and facial cosmetic surgery. Curr Opin Otolaryngol Head Neck Surg. 1996;4: 429-452.

Journal of Voice, Vol. 15, No. 1, 2001