INTRODUCTION
Surgical treatment of unilateral vocal fold paralysis has been widely used to improve vocal quality. Despite lack of movement, if the vocal fold is in a medial position, it provides a more appropriate glottic closure facilitating vocal production. Surgical procedures described to restore paralyzed vocal fold mobility did not produce satisfactory results. Therefore, the most commonly used surgical treatment is directed to repositioning of vocal fold to the midline. Three surgical techniques are currently used: 1) vocal fold injection; 2) arytenoid adduction; 3) medialization laryngoplasty or type I thyroplasty.
Substance injection in the vocal fold, in order to reduce glottic space, may be performed through transoral or percutaneous routes. These techniques date from the beginning of the 20th century, when Bruennings injected paraffin. In recent years, polytef (Teflon) was the most widely used material to fulfill the same purpose1,6,4; after that, the authors described the use of Gelfoam and autologous fat4,8,3,2. There are disadvantages in all of them: formation of granuloma and rigidity of vibration mucosa (Teflon) and absorption of infected material (Gelfoam and fat).
Adduction of arytenoid is performed in order to place the vocal fold at phonation position. The position is obtained when we rotate the arytenoid to a phonation position and suture it. This procedure may be performed alone or combined with medialization laryngoplasty. Adduction of arytenoids may be difficult for some surgeons, especially inexperienced ones.
Medialization laryngoplasty, initially called type I thyroplasty by Isshiki et al.5, is conducted by opening a window on the thyroid cartilage through which an implant is introduced to promote medialization of the paralyzed vocal fold. Currently, the most frequently used material is silicone. The results of this technique are directly correlated with the correct opening of the window on the thyroid cartilage, because it differs from patient to patient because of different cartilage sizes. In addition, although silicone is considered an inert material, there are reports of oral extrusion of implants, which may lead to undesirable and severe complications.
The objective of the present study was to report the initial experience of the authors with the technique of medialization laryngoplasty, using expanded polytetrafluoroethylene (ePTFE - Gore-Tex®) as the medializing material. We concentrated especially on the advantages of using the material during surgical procedure.
MATERIAL AND METHOD
The initial sample consisted of four patients seen at the Service of Otorhinolaryngology at Complexo Santa Casa de Porto Alegre and in private practice. Patients had had unilateral vocal fold paralysis for at least 9 months. There were three female patients and one male patient. As to etiology of paralysis, two cases were secondary to thyroidectomy, one was secondary to esophageal surgery and the other was caused by vagus tumor (schwannoma). Ages ranged from 41 to 63 years.
Surgical technique
The procedure was performed under local anesthesia and intravenous sedation, in an operating room prepared for general anesthesia. Intravenous prednisone (500mg) and cefuroxime (750mg) were administered before the surgery. The antibiotic (PO) was maintained for 5 days after surgery. Local anesthesia was performed with lidocaine at 2% with epinephrine 1:200,000,using enough volume to anesthetize the skin and the deep structures (l0ml). The patient was prepared to a sterile procedure and the face was left free so that fiberscopic exams could be conducted transoperatively.
A horizontal cervical incision of ± 6-8cm was made on the skin at the level of the thyroid cartilage. In order to produce a better esthetical result, we made the incisions following one of the natural neck sulci. Plan dissection was conducted up to exposure of thyroid cartilage. We required a complete view of the cartilage lamina in which we designed the window, except for the upper portion of the superior cornu of the cartilage. The cartilage external perichondrium was detached and preserved.
We used a small diamond or dentist bur to make the window, trying to preserve the internal perichondrium. In young patients, with non-ossified cartilages, we could proceed with a knife. The lower border to the window should be placed 3mm from the lower border of thyroid cartilage, excluding the tuberculum and 0.5cm from midline to women and 0.7mm for men. The size of the window did not influence post-operative results; nevertheless, it should be large enough to receive the ePTFE implant.
The internal perichondrium was detached from the cartilage using a Rosen detacher and a meatus detacher (both instruments from otological surgery). Next, we introduced the tape of ePTEF, evaluating perceptively and continuously the patient's voice. The position was confirmed by laryngeal visualization through fiberscopic exam. At that moment, the implant may be placed anywhere by simply manipulating its tape. After experimenting all possible positions, we left the implant at the position that produced the best vocal quality.
We normally tended to leave the vocal fold more medialized than necessary, because transoperative results modified by the resolution of local edema caused by the manipulation. The implant was fixed on the thyroid cartilage through sutures with mononylon 4.0.
RESULTS
All patients experienced improvement of vocal quality after surgery. The four patients referred good vocal quality, similar to pre-paralysis quality, with reduced breathiness and improved loudness. No complications were detected within a mean follow-up of 4 months.
DISCUSSION
The creation of medialization laryngoplasty using ePTEF was credited to McCulloch and Hoffman, in 19987 The present study emphasizes the promising results of the technique and its easy performance.
Expanded polytetrafluoroethylene was developed by Gore et al. (1971) and it is widely used as vascular prostheses by vascular surgeons9 Biocompatibility of the material, already proved by two decades of experiments, reduces the likelihood of extrusion or other complications of the procedure resultant from reactions to foreign bodies. The material produces minimal inflammatory reaction in adjacent tissues and enables easy removal, if necessary7.
The search for the ideal material will go on. Available autologous materials, such as cartilage, fat and temporal fascia, show the theoretical advantage of not having the risk of extrusion. However, these materials present high rates of reabsorption, modifying the results of vocal quality in the long run.
Synthetic materials, such as Teflon and silicone, have been successfully used; however, complications have been well documented by the literature4,10ong the advantages of laryngoplasty with ePTFE we may list:
1) is does not require special materials;
2) it does not require precision when designing the window on the thyroid cartilage;
3) the ideal position for the placement of graft may be easily reached in the surgery;
4) it has been used for a long time and the rate of complications is very low;
5) based on our initial experience, it seems that it reduced the need for simultaneous arytenoid adduction, because we could find a good position of the implant.
CONCLUSION
The technique of medialization laryngoplasty with ePTFE is an alternative approach to other procedures that intend to bring to the midline a paralyzed vocal fold in order to improve vocal quality. Post-operative results, easy-to-perform technique and low complication rates result in a very promising technique.
REFERENCES
1. ARNOLD, G. E. - Vocal rehabilitation of paralytic dysphonia. IX. Technique of intracordal injection. Arch. Otolaryngol., 76: 358-68, 1962.
2. BAUER, C. A.; VALENTINO, J.; HOFFMAN, H. T - Longterm result of vocal cord augmentation with autogenous fat. Ann. Otol. Rhinol. Laryngol., 104: 871-4, 1995.
3. BRANDENBURG, J. H.; KIRKHAM, W; KOSCHKEE, D. Vocal fold augmentation with autogenous fat. Laryngoscope, 102: 495-500, 1992.
4. HOFFMAN, H. T.; McCULLOCH, T. M. - Anatomic considerations in the surgical treatment of unilateral laryngeal paralysis. Head. Neck, 18: 174-86, 1996.
5. ISSHIKI, N, MORITA, H, OKAMURA, H, HIRAMOT, M. Thyreoplasty as a new phonosurgical technique. Acta Otolaryngot, 78: 451-7, 1 974.
6. LEWY, R. B. - Teflon injection of the vocal cord: complications, errors and precautions. Ann. Otol. Rhinol. Laryngol., 92: 473-4,1983.
7. McCULLCH, T. M.; HOFFMAN, H. T. - Medialization laryngoplasty with expanded polytetrafluoroethylene: surgical technique and preliminary results. Ann. Otol. Rhinol. Laryngol., 107: 427-32, 1998.
8. SCHRAMM, V L.; MAY, M.; LAVORATO, A. S. - Gealfoam paste injection for vocal fold paralysis: temporary rehabilitation of glottic incompetence. Laryngoscope, 88: 1268-73, 1978.
9. SOYER, T.; LEMPINEN, M.; COOPER, E; NORTON, L.; EISEMAN, B. - A new venous prosthesis. Surgery, 72: 86472, 1972.
10. TUCKER, H. M.; WANAMAKER, J.; TROTT, M.; HICKS, D. - Complications of laryngeal framework surgery (phonosurgery). Laryngoscope, 103: 525-8, 1993.
* Professor of the Discipline of Otorhinolaryngology at FFFCMPA/CHSC.
** Resident Physician of the Service of Otorhinolaryngology at FFFCMPA/CHSC.
Study conducted at the Discipline of Otorhinolaryngology at Fundação Faculdade Federal de Ciências Medicas de Porto Alegre/Complexo Hospitalar Santa Casa de Porto Alegre (FFFCMPA/CHSC).
Address correspondence to: Prof. Dr. Geraldo Druck Sant'Anna - Rua Mostardeiro, 157/701 - 90430-001 Porto Alegre /RS.
Telephone/Fax: (55 51) 222-6365 - E-mail: gds@plug-in.com.br
Article submitted on December 11, 2000. Article accepted on January 19, 2001.
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