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Polydimethylsiloxane Injection Laryngoplasty for Unilateral Vocal Fold Paralysis: Long-Term Results
ARTICLE IN PRESS Polydimethylsiloxane Injection Laryngoplasty for Unilateral Vocal Fold Paralysis: Long-Term Results *Francesco Mattioli, *Margherita Bettini, *Cecilia Botti, *Giulia Busi, *Sauro Tassi, †Andrea Malagoli, *Gabriele Molteni, *Marco Trebbi, ‡Maria Pia Luppi, and *Livio Presutti, *†‡Modena, Italy Summary: Objectives. To analyze the long-term objective, perceptive, and subjective outcomes after endoscopic polydimethylsiloxane (PDMS) injection laryngoplasty in unilateral vocal fold paralysis. Study design. A retrospective study carried out between January 2008 and January 2012. Setting. Head and Neck Department, University Hospital of Modena, Modena, Italy. Methods. This was a retrospective analysis of 26 patients with unilateral vocal fold paralysis who underwent endoscopic injection of PDMS under general anesthesia. A voice evaluation protocol was performed for all patients, which included videolaryngostroboscopy, maximum phonation time, fundamental frequency, analysis of the harmonic structure of the vowel /a/ and the word /aiuole/, Grade of Dysphonia, Instability, Roughness, Breathiness, Asthenia, and Strain scale, and Voice Handicap Index. The protocol was performed before surgery, in the immediate postoperative period, and at least 3 years after surgery. The mean follow-up period was 73 months (range 39–119 months). Results. The statistical analysis showed a significant improvement (P < 0.01) for all of the objective, perceptive, and subjective parameters by comparison between the preoperative and long-term follow-up data; moreover, no statistically significant difference was found between the postoperative and long-term follow-up data. This indicates that injection laryngoplasty with PDMS guarantees long-lasting effects over time. No complications were reported in our series. Conclusion. Injection laryngoplasty with PDMS can be considered to be a minimally invasive and safe technique for the treatment of unilateral vocal fold paralysis. Moreover, it allows very good and stable results to be obtained over time, avoiding repeated treatments and improving the quality of life of the patients. Key Words: Vocal fold paralysis–Polydimethylsiloxane–Speech therapy–Injection laryngoplasty–Endoscopic injection laryngoplasty. INTRODUCTION Vocal fold paralysis is the result of congenital, viral, neurological, traumatic, iatrogenic, or neoplastic injuries to the vagus or the recurrent laryngeal nerve.1,2 If no etiology is found, it is defined as idiopathic.3 The paralyzed vocal fold can be in adduction or in a paramedian or lateral position. In unilateral vocal fold paralysis (UVFP), a vocal fold fixed in adduction does not cause important symptoms, as the contralateral vocal fold well compensates the gap; however, a vocal fold in a paramedian or lateral position causes inadequate phonation with breathlessness of voice and hoarseness, associated with possible swallowing disease and bolus inhalation because of glottic incompetence. This condition has a negative impact on the quality of life of the patient because of both phonatory dysfunction and psychological impact. Difficulties in communication interfere with everyday social life and sometimes with work activities, for example, for singers, teachers, etc. In these cases, therapy is necessary. Voice therapy is attempted as early as possible, and in the case of poor phoniatric results, phonosurgery is performed.4 The goal of surgery is the medialization of the paralyzed vocal cord to reduce the glottic gap and to restore the quality of voice as much as possible so Accepted for publication December 28, 2016. From the *Head and Neck Department, University Hospital of Modena, Modena, Italy; †Department of Medical and Surgical Sciences for Children and Adults, University Hospital of Modena, Modena, Italy; and the ‡Speech Therapist in H ead and Neck Department, University Hospital of Modena, Modena, Italy. Address correspondence and reprint requests to Cecilia Botti, Head and Neck Department, University Hospital of Modena, Modena, Italy. E-mail: [email protected] Journal of Voice, Vol. ■■, No. ■■, pp. ■■-■■ 0892-1997 © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jvoice.2016.12.017
as to improve the quality of life of the patient with stable results over time. Two main surgical approaches are performed: type I thyroplasty5 and injection laryngoplasty.6,7 The first approach requires an external incision and is more invasive, whereas injection laryngoplasty is a rapid and less invasive endoscopic procedure. It consists of the injection of a substance in the lateral part of the paralyzed vocal cord to increase its volume and medialize the cord with a reduction in the glottic gap.7 Materials used need to be biocompatible and many have been tried up to now. The first materials used (fat, bovine collagen, hyaluronic acid, cartilage) were rapidly reabsorbed,8 whereas others were poorly biocompatible (paraffin oil, Teflon).9 A slowly reabsorbable material, calcium hydroxylapatite (Radiesse Voice), has allowed good results to be obtained, but over time, it can dislocate or it is reabsorbed although slowly. In 1989, a new biocompatible nonreabsorbable material, polydimethylsiloxane (PDMS), was introduced in surgery. It was first used in plastic surgery and urology.10,11 Since 1993, it has been used in laryngology, with the expectation of results that would be stable over time. However, only a few studies have reported the use of PDMS for the treatment of UVFP.12–18 Most of the studies only considered subjective evaluations, such as the GIRBAS (Grade of Dysphonia, Instability, Roughness, Breathiness, Asthenia, and Strain) scale19 or the Voice Handicap Index (VHI).20 Moreover, there are no long-term results in the literature. Our previous study documented the short-term functional results and compared objective and subjective voice measures after endoscopic laryngoplasty with injection of PDMS (Vox Implants, Bioplasty BV, Geleen, The Netherlands) for the treatment of UVFP and verified PDMS biocompatibility in the vocal fold. It showed an improvement in results after a 4-month follow-up in
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comparison to preoperative performances.4 The aim of this study is to document long-term functional results after injection laryngoplasty with PDMS in patients with UVFP after at least a 3-year follow-up period, in comparison to preoperative and immediate postoperative results. MATERIALS AND METHODS Patient selection This was a retrospective analysis of patients who underwent injection laryngoplasty with PDMS at the ENT Department of the University Hospital of Modena between January 2008 and January 2012. In that period, 42 patients with UVFP underwent endoscopic injection of PDMS. In all patients, the endoscopic injection was performed 1 year or more after the onset of the palsy. Before surgery, most of the patients underwent early speech therapy (within 6 months after the onset of the palsy) without sufficient improvement. All of these patients did not show satisfactory voice improvement, due either to delayed voice therapy or to incomplete voice treatment. Among them, we only included patients with at least a 3-year follow-up after the procedure. Of the 42 patients, only 26 had 3-year follow-up functional results (two patients moved abroad, for one patient the cricoarytenoid junction block was completely resolved after surgery, and 13 patients did not complete the requested follow-up period). The study population was composed of 15 women and 11 men with a mean age of 60 years (range 28–85 years). The etiology of vocal cord palsy in our 26 patients is presented in Figure 1. Injection technique Laryngoplasties by endoscopic injection were all performed by microlaryngoscopy under general anesthesia. A good laryngeal exposure is required. The procedure requires two injection points. The first injection point is into the thyroarytenoid muscle laterally and deep into the vocal fold apophysis, to medialize the vocal process and the posterior third of the vocal cord (Figure 2A); the second injection point is lateral to the middle third of the
thyroarytenoid muscle, near to the internal surface of the thyroid cartilage, to medialize the anterior and medial third of the vocal fold, with a result that is as effective as external laryngeal frame surgery (Figure 2B). To avoid an overdose of injected material, a maximum of 2 mL of Vox Implants was injected in each patient. After injection, we performed a redistribution of textured silicon by modeling the vocal fold with an aspirator or a Bouchayer forceps as necessary. Further details about the injection technique have already been described in our previous study.4 Voice evaluation We collected data about the patients before surgery (some days before surgery or on day 0 immediately before surgery), within the first weeks after surgery, and at least 3 years after surgery. Speech-language pathologists and otolaryngologists evaluated all patients with questions about their medical history and an instrumental voice evaluation protocol. Analysis of the results followed the protocol of subjective and objective evaluations of dysphonia proposed by Dejonckere et al,21 and approved by the European Laryngological Society since 2001. In Italy, a simplified revision of this protocol was introduced in the Official Relation of XXXVI National Congress of Italian Society of Phoniatrics and Speech Therapy. All patients underwent videolaryngostroboscopy (VLS) (Mediastroboscope-Atmos, Atmos Medizin Technik GmbH & Co. KG, Leutkirch, Germany) to evaluate the position of the vocal cord (median, intermediate, lateral) and the edge of the vocal fold (bowing, concave, linear). Acoustic (CSL Model 4300B-KAY, Elemetrics Corp., Lincoln Park, NJ) and aerodynamic analyses of the voice were performed to establish maximum phonation time with a sustained vocal /a/ (MPT), fundamental frequency (Fo), and the quality of voice with the analysis of harmonic structure of the vowel /a/ and the word /aiuole/ according to the classification ofYanagihara.22 All VLS and acoustic analyses were digitally recorded. Furthermore, a perceptive evaluation of the patients’ voices has been made using the GIRBAS scale19 that assesses six vocal
FIGURE 1. Etiology of vocal cord paralysis in our 26 patients.
ARTICLE IN PRESS Francesco Mattioli, et al
Laryngoplasty for Unilateral Vocal Fold Paralysis
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A
B FIGURE 2. Injection technique. A. First point of injection into the thyroarytenoid muscle laterally and deep into the vocal fold apophysis (an exeresis of a vocal cord nodule was just performed controlaterally). B. Second point of injection lateral to the middle third of the thyroarytenoid muscle.
parameters on a scale with 3° of severity (G—overall Grade of dysphonia, I—degree of Instability of the voice, R—degree of Roughness of the voice, B—degree of Breathiness of the voice, A—degree of Asthenia of the voice, S—degree of Strain of the voice). Subjective self-evaluations have been performed by computing the VHI (30 questions divided into three areas: functional, emotional, and physical aspects as indicated by Jacobson et al20) to determine the effects on the patient’s social life and activities caused by the voice problem. Statistical analysis We compared all of the parameters previously defined and we verified the statistical significance between preoperative, postoperative, and follow-up data variations. Results for the position and edge of the vocal cord and the harmonic structure of the vowel /a/ and word /aiuole/ have been compared with the chi-squared test, GIRBAS with the Student’s t test, and MPT, Fo, and VHI with the Wilcoxon test. A P value <0.01 was considered to be statistically significant. RESULTS The mean follow-up period was 73 months (range 39–119 months). All of the parameters evaluated improved after the injection laryngoplasty as shown from both the postoperative and long-term
follow-up results. The statistical analysis showed a significant difference for almost all of the parameters between the preoperative groups and postoperative groups and between the preoperative groups and follow-up groups, whereas no significant difference was found between the postoperative and follow-up groups. VLS analysis showed that, after injection of PDMS, the position of the vocal cord was median for most of the patients and intermediate for the others (Figure 3). Also, the edge of the vocal fold was linear for all patients after the procedure (Figure 4). Therefore, we obtained good outcomes in terms of glottic closure with stable results over the years as shown by statistical analysis. The median MPT was 4.75 seconds before injection, 12 seconds during the postoperative examinations, and 14.5 seconds at long-term follow-up, with statistically significant differences between the three groups. At long-term follow-up, 88% of patients had a value of MPT greater than 10 seconds, which is the normal value (Figure 5). In men, the median Fo was not significantly modified after the procedure and at long-term follow-up (Fo preoperative: 147 Hz; postoperative: 145 Hz; long-term follow-up: 150 Hz); however, it remained within normal levels for men (80–150 Hz). In women, the median Fo was significantly increased after the procedure and reached normal levels for the female population
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FIGURE 3. Position of vocal fold (P value preop vs postop: <0.01; postop vs long-term FU: 1; preop vs long-term FU: <0.01). FU, followup; postop, postoperative; preop, preoperative. (180–250 Hz); no significant difference was found between the postoperative and long-term follow-up results (Fo preoperative: 164 Hz; postoperative: 210 Hz; long-term follow-up: 190 Hz) (Figure 6). With regard to the quality of voice, the harmonic structure of both the vowel /a/ and word /aiuole/ showed a statistically significant improvement after treatment and results remained stable over time. Most of the patients’ results were in Yanagihara grade I or II classes at long-term follow-up (Figures 7 and 8). The GIRBAS scale and VHI also showed an improvement after PDMS injection. At postoperative and long-term follow-up evaluation, all GIRBAS parameters were normal or mildly altered in most of the cases (average values at long-term follow-up were: G 0.5; I 0.4; R 0.6; B 0.07; A 0.2; S 0.04). Moreover, all of them apart from the degree of voice strain (S) improved significantly between the preoperative and postoperative evaluations whereas no significant difference was found by comparison between the postoperative and long-term follow-up evaluations (Figure 9).
FIGURE 4. Edge of vocal fold (P value preop vs postop: <0.01; postop vs long-term FU: 1; preop vs long-term FU: <0.01). FU, follow-up; postop, postoperative; preop, preoperative.
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FIGURE 5. Maximum phonation time (MPT). The dotted line represents the normal value of MPT (P value preop vs postop: <0.01; postop vs long-term FU: <0.01; preop vs long-term FU: <0.01). FU, followup; postop, postoperative; preop, preoperative. The median global VHI was 59 before injection, 19 during the postoperative examinations, and 16 at long-term followup. At the last evaluation, 92% of patients had a normal or mildly altered voice (global VHI < 40) (Figure 10). The same trend was present for the VHI with regard to the functional aspect (preoperative median value: 20, postoperative: 5, long-term follow-up: 4), emotional aspect (preoperative median value: 13, postoperative: 2, long-term follow-up: 2), and physical aspect (preoperative median value: 25, postoperative: 10, long-term follow-up: 8). DISCUSSION The first treatment for UVFP is always represented by early speech therapy, which is indicated in the treatment of laryngeal
FIGURE 6. Fundamental frequency (Fo) in the female group. The dotted lines represent the normal range of Fo in women (P value preop vs postop: <0.02; postop vs long-term FU: <0.06; preop vs long-term FU: <0.08). FU, follow-up; postop, postoperative; preop, preoperative.
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Laryngoplasty for Unilateral Vocal Fold Paralysis
FIGURE 7. Spectrogram of vowel /a/ (P value preop vs postop: <0.01; postop vs long-term FU: 0.57; preop vs long-term FU: <0.01). FU, follow-up; postop, postoperative; preop, preoperative. paralysis, in particular within 6 months from the occurrence of the paralysis. In our experience,23,24 speech therapy guarantees a recovery of the motility of the nerve in 68% of patients, if the nerve is preserved. It can be useful to avoid cricoarytenoid joint ankylosis and to learn compensation techniques to restore glottic closure, to improve the quality of voice, even if recovery of motility is not possible. If speech therapy fails, surgery becomes the treatment of choice. The surgical procedure must be safe and easy to perform, and it has to guarantee good and stable results over time, to avoid the patient undergoing multiple surgeries. In our experience, the best time to perform surgery is 1 year after the onset of paralysis. For the treatment of UVFP, injection laryngoplasty represents a minimally invasive technique in contrast with type I thyroplasty that requires external incision and prolonged surgical time. The injection technique is also rapid and relatively easy to learn, so much so that some authors practice a transcutaneous injection of different materials under local anesthesia.25,26 To obtain long-lasting effects over time, the choice of material is very important. In our experience, PDMS is a good material
FIGURE 8. Spectrogram of word /aiuole/ (P value preop vs postop: <0.01; postop vs long-term FU: 0.2; preop vs long-term FU: <0.01). FU, follow-up; postop, postoperative; preop, preoperative.
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because of its high biocompatibility: in the literature, rare cases of early and late adverse reactions have been reported.27–29 Hyaluronic acid,30 and autologous and bovine collagen31,32 have given good results, but usually require overcorrection and repeated injections33 because they are absorbable materials. Autologous fat34,35 seems to guarantee effects sustainable over 12 months even if it requires a harvesting incision. Recently, calcium hydroxyapatite36 has been introduced for the treatment of UVFP. It allows excellent clinical results to be achieved that remain stable over 12 months37 because it is a slowly reabsorbable material. However, a higher risk of granuloma formation and distant migration compared with PDMS has been reported.38 At our institution, we have used PDMS since 2003 for the treatment of different diseases. These include voice rehabilitation after cordectomy, soft palate paralysis, periprosthetic leakage in total laryngectomy, swallowing disease after partial laryngectomy, as well as vocal cord paralysis. Our previous study4 demonstrated that the injection of PDMS in patients with UVFP guarantees a significant improvement in acoustic, aerodynamic, perceptive, and subjective evaluations with stable results over time (median follow-up 21.7 months). In the literature, no studies on injection laryngoplasty with PDMS have analyzed the long-term outcomes of the procedure; all of the studies previously mentioned have, at most, a mean follow-up of 24 months. The aim of our work was to demonstrate that PDMS can guarantee good long-term functional results. For each patient in this study, follow-up data were collected for at least 3 years after the procedure and mean followup was longer than 70 months. We obtained a significant improvement in the objective (position and edge of vocal fold, MPT, Fo in women, analysis of the spectrogram for the vowel /a/ and the word /aiuole/), perceptive (GIRBAS), and subjective parameters (VHI) after treatment as demonstrated by comparisons between the preoperative and postoperative data. Moreover, our results remained stable over time. In particular, a significant improvement was seen for all of the parameters by comparison between the preoperative and long-term follow-up data, and no statistically significant difference was found between the postoperative and long-term follow-up data. In fact, PDMS is considered to be a nonabsorbable material so it can guarantee stable results and usually no further injections are required. On the other hand, this makes PDMS injection irreversible so we believe that laryngoplasty with PDMS in suspended microlaryngoscopy should be performed under general anesthesia (instead of local anesthesia) because that minimizes the potential for suboptimal placement of the material. A prior accurate VLS examination and an accurate intraoperative evaluation of the anatomical result after injection are mandatory to obtain good functional outcomes. No reabsorption problems, foreign-body reactions, or migration of the PDMS were reported in our series. Clearly, the particle size of the PDMS combined with its surface texture prevents material dislodgement and migration via the lymphatic pathways. An analysis of a larger series should be useful to confirm our results.
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FIGURE 9. GIRBAS scale. P value preop vs postop: <0.01 for all the parameters except S (0.1); postop vs long-term FU: >0.01 for all the parameters; preop vs long-term FU: <0.01 for all the parameters except S (0.07). FU, follow-up; GIRBAS, Grade of Dysphonia, Instability, Roughness, Breathiness, Asthenia, and Strain; postop, postoperative; preop, preoperative.
CONCLUSION Our experience has demonstrated that injection laryngoplasty with PDMS is a minimally invasive procedure for the treatment of UVFP and guarantees stable results over time. Therefore, it represents a good alternative to framework surgery. PDMS seems to be a safe and well-tolerated material because of its high biocompatibility (no perioperative or postoperative complications were reported in our series). Moreover, it is a nonreabsorbable material that allows the objective, perceptive, and subjective outcomes to remain unchanged over time, avoiding repeated treatments. In the end, injection laryngoplasty with PDMS improves the quality of life of patients with UVFP. REFERENCES
FIGURE 10. Global VHI (P value preop vs postop: <0.01; postop vs long-term FU: <0.73; preop vs long-term FU: <0.01). FU, followup; postop, postoperative; preop, preoperative; VHI, Voice Handicap Index.
1. Kelchner LN, Stemple JC, Gerdeman E, et al. Etiology, pathophysiology, treatment choices, and voice results for unilateral adductor vocal fold paralysis: a 3-year retrospective. J Voice. 1999;13:592–601. 2. MacGregor FB, Roberts DN, Howard DJ, et al. Vocal fold palsy: a reevaluation of investigations. J Laryngol Otol. 1994;108:193–196. Review. 3. Ward PH, Berci G. Observations on so-called idiopathic vocal cord paralysis. Ann Otol Rhinol Laryngol. 1982;91(6 pt 1):558–563. 4. Bergamini G, Alicandri-Ciufelli M, Molteni G, et al. Therapy of unilateral vocal fold paralysis with polydimethylsiloxane injection laryngoplasty: our experience. J Voice. 2010;24:119–125.
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5. Uloza V, Pribuisiene R, Saferis V. Multidimensional assessment of functional outcomes of medialization thyroplasty. Eur Arch Otorhinolaryngol. 2005;262:616–621. 6. Harries ML. Unilateral vocal fold paralysis: a review of the current methods of surgical rehabilitation. J Laryngol Otol. 1996;110:111–116. Review. 7. Arnold GE. Vocal rehabilitation of paralytic dysphonia. VI. Further studies of intracordal injection materials. Arch Otolaryngol. 1961;73:290–294. 8. Laccourreye O, Papon JF, Kania R, et al. Intracordal injection of autologous fat in patients with unilateral laryngeal nerve paralysis: long-term results from the patient’s perspective. Laryngoscope. 2003;113:541–545. 9. Chu PY, Chang SY. Transoral Teflon injection under flexible laryngovideostroboscopy for unilateral vocal fold paralysis. Ann Otol Rhinol Laryngol. 1997;106:783–786. 10. Ersek RA, Gregory SR, Salisbury AV. Bioplastique at 6 years: clinical outcome studies. Plast Reconstr Surg. 1997;100:1570–1574. 11. Guys JM, Simeoni-Alias J, Fakhro A, et al. Use of polydimethylsiloxane for endoscopic treatment of neurogenic urinary incontinence in children. J Urol. 1999;162:2133–2135. 12. Sittel C, Thumfart WF, Pototschnig C, et al. Textured polydimethylsiloxane elastomers in the human larynx: safety and efficiency of use. J Biomed Mater Res. 2000;53:646–650. 13. Alves CB, Loughran S, MacGregor FB, et al. Bioplastique medialization therapy improves the quality of life in terminally ill patients with vocal cord palsy. Clin Otolaryngol Allied Sci. 2002;27:387–391. 14. Duruisseau O, Wagner I, Fugain C, et al. Endoscopic rehabilitation of vocal cord paralysis with a silicone elastomer suspension implant. Otolaryngol Head Neck Surg. 2004;131:241–247, Review. 15. Sittel C, Echternach M, Federspil PA, et al. Polydimethylsiloxane particles for permanent injection laryngoplasty. Ann Otol Rhinol Laryngol. 2006; 115:103–109. 16. Turner F, Duflo S, Michel J, et al. Endoscopic medialization with Vox implant: our experience. Rev Laryngol Otol Rhinol (Bord). 2006;127:339– 343. 17. Bihari A, Mészáros K, Reményi A, et al. Voice quality improvement after management of unilateral vocal cord paralysis with different techniques. Eur Arch Otorhinolaryngol. 2006;263:1115–1120. 18. Hamilton DW, Sachidananda R, Carding PN, et al. Bioplastique injection laryngoplasty: voice performance outcome. J Laryngol Otol. 2007;121:472– 475. 19. Dejonckere PH, Remacle M, Fresnel-Elbaz E, et al. Differentiated perceptual evaluation of pathological voice quality: reliability and correlations with acoustic measurements. Rev Laryngol Otol Rhinol (Bord). 1996;117:219–224. 20. Jacobson BH, Johnson A, Grywalski C, et al. The Voice Handicap Index (VHI): development and validation. Am J Speech Lang Pathol. 1997;6:66–69. 21. Dejonckere PH, Bradley P, Clemente P, et al. A basic protocol for functional assessment of voice pathology, especially for investigating the efficacy of (phonosurgical) treatments and evaluating new assessment techniques. Guideline elaborated by the Committee on Phoniatrics of the European Laryngological Society (ELS). Eur Arch Otorhinolaryngol. 2001;258:77–82.
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22. Yanagihara N. Significance of harmonic changes and noise components in hoarseness. J Speech Hear Res. 1967;10:531–541. 23. Mattioli F, Bergamini G, Alicandri-Ciufelli M, et al. The role of early voice therapy in the incidence of motility recovery in unilateral vocal fold paralysis. Logoped Phoniatr Vocol. 2011;36:40–47. 24. Mattioli F, Menichetti M, Bergamini G, et al. Results of early versus intermediate or delayed voice therapy in patients with unilateral vocal fold paralysis: our experience in 171 patients. J Voice. 2015;29:455–458. 25. Pratap R, Mehta P, Blagnys B, et al. Early results for treatment of unilateral vocal fold palsy with injection medialisation under local anaesthetic. J Laryngol Otol. 2009;123:873–876. 26. Min JY, Hong SD, Kim K, et al. Long-term results of Artecoll injection laryngoplasty for patients with unilateral vocal fold motion impairment: safety and clinical efficacy. Arch Otolaryngol Head Neck Surg. 2008;134:490– 496. 27. Lombardi T, Samson J, Plantier F, et al. Orofacial granulomas after injection of cosmetic fillers. Histopathologic and clinical study of 11 cases. J Oral Pathol Med. 2004;33:115–120. 28. Ovari A, Witt G, Schuldt T, et al. Polydimethylsiloxane for injection laryngoplasty: two cases necessitating tracheotomy. Eur Arch Otorhinolaryngol. 2014;271:839–844. 29. Leuchter I, Giovanni A. Description of complications after injection laryngoplasty with polydimethylsiloxane. Rev Laryngol Otol Rhinol (Bord). 2009;130:69–72. 30. Lau DP, Lee GA, Wong SM, et al. Injection laryngoplasty with hyaluronic acid for unilateral vocal cord paralysis. Randomized controlled trial comparing two different particle sizes. J Voice. 2010;24:113–118. 31. Remacle M, Marbaix E, Hamoir M, et al. Correction of glottic insufficiency by collagen injection. Ann Otol Rhinol Laryngol. 1990;99:438–444. 32. Remacle M, Lawson G, Keghian J, et al. Use of injectable autologous collagen for correcting glottic gaps: initial results. J Voice. 1999;13:280– 288. 33. Hertegård S, Hallén L, Laurent C, et al. Cross-linked hyaluronan versus collagen for injection treatment of glottal insufficiency: 2-year follow-up. Acta Otolaryngol. 2004;124:1208–1214. 34. Khadivi E, Akbarian M, Khazaeni K, et al. Outcomes of autologous fat injection laryngoplasty in unilateral vocal cord paralysis. Iran J Otorhinolaryngol. 2016;28:215–219. 35. Fang TJ, Li HY, Gliklich RE, et al. Outcomes of fat injection laryngoplasty in unilateral vocal cord paralysis. Arch Otolaryngol Head Neck Surg. 2010;136:457–462. 36. Rosen CA, Gartner-Schmidt J, Casiano R, et al. Vocal fold augmentation with calcium hydroxylapatite: twelve-month report. Laryngoscope. 2009; 119:1033–1041. 37. Shen T, Damrose EJ, Morzaria S. A meta-analysis of voice outcome comparing calcium hydroxylapatite injection laryngoplasty to silicone thyroplasty. Otolaryngol Head Neck Surg. 2013;148:197–208. 38. DeFatta RA, Chowdhury FR, Sataloff RT. Complications of injection laryngoplasty using calcium hydroxylapatite. J Voice. 2012;26:614–618.
as to improve the quality of life of the patient with stable results over time. Two main surgical approaches are performed: type I thyroplasty5 and injection laryngoplasty.6,7 The first approach requires an external incision and is more invasive, whereas injection laryngoplasty is a rapid and less invasive endoscopic procedure. It consists of the injection of a substance in the lateral part of the paralyzed vocal cord to increase its volume and medialize the cord with a reduction in the glottic gap.7 Materials used need to be biocompatible and many have been tried up to now. The first materials used (fat, bovine collagen, hyaluronic acid, cartilage) were rapidly reabsorbed,8 whereas others were poorly biocompatible (paraffin oil, Teflon).9 A slowly reabsorbable material, calcium hydroxylapatite (Radiesse Voice), has allowed good results to be obtained, but over time, it can dislocate or it is reabsorbed although slowly. In 1989, a new biocompatible nonreabsorbable material, polydimethylsiloxane (PDMS), was introduced in surgery. It was first used in plastic surgery and urology.10,11 Since 1993, it has been used in laryngology, with the expectation of results that would be stable over time. However, only a few studies have reported the use of PDMS for the treatment of UVFP.12–18 Most of the studies only considered subjective evaluations, such as the GIRBAS (Grade of Dysphonia, Instability, Roughness, Breathiness, Asthenia, and Strain) scale19 or the Voice Handicap Index (VHI).20 Moreover, there are no long-term results in the literature. Our previous study documented the short-term functional results and compared objective and subjective voice measures after endoscopic laryngoplasty with injection of PDMS (Vox Implants, Bioplasty BV, Geleen, The Netherlands) for the treatment of UVFP and verified PDMS biocompatibility in the vocal fold. It showed an improvement in results after a 4-month follow-up in
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comparison to preoperative performances.4 The aim of this study is to document long-term functional results after injection laryngoplasty with PDMS in patients with UVFP after at least a 3-year follow-up period, in comparison to preoperative and immediate postoperative results. MATERIALS AND METHODS Patient selection This was a retrospective analysis of patients who underwent injection laryngoplasty with PDMS at the ENT Department of the University Hospital of Modena between January 2008 and January 2012. In that period, 42 patients with UVFP underwent endoscopic injection of PDMS. In all patients, the endoscopic injection was performed 1 year or more after the onset of the palsy. Before surgery, most of the patients underwent early speech therapy (within 6 months after the onset of the palsy) without sufficient improvement. All of these patients did not show satisfactory voice improvement, due either to delayed voice therapy or to incomplete voice treatment. Among them, we only included patients with at least a 3-year follow-up after the procedure. Of the 42 patients, only 26 had 3-year follow-up functional results (two patients moved abroad, for one patient the cricoarytenoid junction block was completely resolved after surgery, and 13 patients did not complete the requested follow-up period). The study population was composed of 15 women and 11 men with a mean age of 60 years (range 28–85 years). The etiology of vocal cord palsy in our 26 patients is presented in Figure 1. Injection technique Laryngoplasties by endoscopic injection were all performed by microlaryngoscopy under general anesthesia. A good laryngeal exposure is required. The procedure requires two injection points. The first injection point is into the thyroarytenoid muscle laterally and deep into the vocal fold apophysis, to medialize the vocal process and the posterior third of the vocal cord (Figure 2A); the second injection point is lateral to the middle third of the
thyroarytenoid muscle, near to the internal surface of the thyroid cartilage, to medialize the anterior and medial third of the vocal fold, with a result that is as effective as external laryngeal frame surgery (Figure 2B). To avoid an overdose of injected material, a maximum of 2 mL of Vox Implants was injected in each patient. After injection, we performed a redistribution of textured silicon by modeling the vocal fold with an aspirator or a Bouchayer forceps as necessary. Further details about the injection technique have already been described in our previous study.4 Voice evaluation We collected data about the patients before surgery (some days before surgery or on day 0 immediately before surgery), within the first weeks after surgery, and at least 3 years after surgery. Speech-language pathologists and otolaryngologists evaluated all patients with questions about their medical history and an instrumental voice evaluation protocol. Analysis of the results followed the protocol of subjective and objective evaluations of dysphonia proposed by Dejonckere et al,21 and approved by the European Laryngological Society since 2001. In Italy, a simplified revision of this protocol was introduced in the Official Relation of XXXVI National Congress of Italian Society of Phoniatrics and Speech Therapy. All patients underwent videolaryngostroboscopy (VLS) (Mediastroboscope-Atmos, Atmos Medizin Technik GmbH & Co. KG, Leutkirch, Germany) to evaluate the position of the vocal cord (median, intermediate, lateral) and the edge of the vocal fold (bowing, concave, linear). Acoustic (CSL Model 4300B-KAY, Elemetrics Corp., Lincoln Park, NJ) and aerodynamic analyses of the voice were performed to establish maximum phonation time with a sustained vocal /a/ (MPT), fundamental frequency (Fo), and the quality of voice with the analysis of harmonic structure of the vowel /a/ and the word /aiuole/ according to the classification ofYanagihara.22 All VLS and acoustic analyses were digitally recorded. Furthermore, a perceptive evaluation of the patients’ voices has been made using the GIRBAS scale19 that assesses six vocal
FIGURE 1. Etiology of vocal cord paralysis in our 26 patients.
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A
B FIGURE 2. Injection technique. A. First point of injection into the thyroarytenoid muscle laterally and deep into the vocal fold apophysis (an exeresis of a vocal cord nodule was just performed controlaterally). B. Second point of injection lateral to the middle third of the thyroarytenoid muscle.
parameters on a scale with 3° of severity (G—overall Grade of dysphonia, I—degree of Instability of the voice, R—degree of Roughness of the voice, B—degree of Breathiness of the voice, A—degree of Asthenia of the voice, S—degree of Strain of the voice). Subjective self-evaluations have been performed by computing the VHI (30 questions divided into three areas: functional, emotional, and physical aspects as indicated by Jacobson et al20) to determine the effects on the patient’s social life and activities caused by the voice problem. Statistical analysis We compared all of the parameters previously defined and we verified the statistical significance between preoperative, postoperative, and follow-up data variations. Results for the position and edge of the vocal cord and the harmonic structure of the vowel /a/ and word /aiuole/ have been compared with the chi-squared test, GIRBAS with the Student’s t test, and MPT, Fo, and VHI with the Wilcoxon test. A P value <0.01 was considered to be statistically significant. RESULTS The mean follow-up period was 73 months (range 39–119 months). All of the parameters evaluated improved after the injection laryngoplasty as shown from both the postoperative and long-term
follow-up results. The statistical analysis showed a significant difference for almost all of the parameters between the preoperative groups and postoperative groups and between the preoperative groups and follow-up groups, whereas no significant difference was found between the postoperative and follow-up groups. VLS analysis showed that, after injection of PDMS, the position of the vocal cord was median for most of the patients and intermediate for the others (Figure 3). Also, the edge of the vocal fold was linear for all patients after the procedure (Figure 4). Therefore, we obtained good outcomes in terms of glottic closure with stable results over the years as shown by statistical analysis. The median MPT was 4.75 seconds before injection, 12 seconds during the postoperative examinations, and 14.5 seconds at long-term follow-up, with statistically significant differences between the three groups. At long-term follow-up, 88% of patients had a value of MPT greater than 10 seconds, which is the normal value (Figure 5). In men, the median Fo was not significantly modified after the procedure and at long-term follow-up (Fo preoperative: 147 Hz; postoperative: 145 Hz; long-term follow-up: 150 Hz); however, it remained within normal levels for men (80–150 Hz). In women, the median Fo was significantly increased after the procedure and reached normal levels for the female population
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FIGURE 3. Position of vocal fold (P value preop vs postop: <0.01; postop vs long-term FU: 1; preop vs long-term FU: <0.01). FU, followup; postop, postoperative; preop, preoperative. (180–250 Hz); no significant difference was found between the postoperative and long-term follow-up results (Fo preoperative: 164 Hz; postoperative: 210 Hz; long-term follow-up: 190 Hz) (Figure 6). With regard to the quality of voice, the harmonic structure of both the vowel /a/ and word /aiuole/ showed a statistically significant improvement after treatment and results remained stable over time. Most of the patients’ results were in Yanagihara grade I or II classes at long-term follow-up (Figures 7 and 8). The GIRBAS scale and VHI also showed an improvement after PDMS injection. At postoperative and long-term follow-up evaluation, all GIRBAS parameters were normal or mildly altered in most of the cases (average values at long-term follow-up were: G 0.5; I 0.4; R 0.6; B 0.07; A 0.2; S 0.04). Moreover, all of them apart from the degree of voice strain (S) improved significantly between the preoperative and postoperative evaluations whereas no significant difference was found by comparison between the postoperative and long-term follow-up evaluations (Figure 9).
FIGURE 4. Edge of vocal fold (P value preop vs postop: <0.01; postop vs long-term FU: 1; preop vs long-term FU: <0.01). FU, follow-up; postop, postoperative; preop, preoperative.
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FIGURE 5. Maximum phonation time (MPT). The dotted line represents the normal value of MPT (P value preop vs postop: <0.01; postop vs long-term FU: <0.01; preop vs long-term FU: <0.01). FU, followup; postop, postoperative; preop, preoperative. The median global VHI was 59 before injection, 19 during the postoperative examinations, and 16 at long-term followup. At the last evaluation, 92% of patients had a normal or mildly altered voice (global VHI < 40) (Figure 10). The same trend was present for the VHI with regard to the functional aspect (preoperative median value: 20, postoperative: 5, long-term follow-up: 4), emotional aspect (preoperative median value: 13, postoperative: 2, long-term follow-up: 2), and physical aspect (preoperative median value: 25, postoperative: 10, long-term follow-up: 8). DISCUSSION The first treatment for UVFP is always represented by early speech therapy, which is indicated in the treatment of laryngeal
FIGURE 6. Fundamental frequency (Fo) in the female group. The dotted lines represent the normal range of Fo in women (P value preop vs postop: <0.02; postop vs long-term FU: <0.06; preop vs long-term FU: <0.08). FU, follow-up; postop, postoperative; preop, preoperative.
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FIGURE 7. Spectrogram of vowel /a/ (P value preop vs postop: <0.01; postop vs long-term FU: 0.57; preop vs long-term FU: <0.01). FU, follow-up; postop, postoperative; preop, preoperative. paralysis, in particular within 6 months from the occurrence of the paralysis. In our experience,23,24 speech therapy guarantees a recovery of the motility of the nerve in 68% of patients, if the nerve is preserved. It can be useful to avoid cricoarytenoid joint ankylosis and to learn compensation techniques to restore glottic closure, to improve the quality of voice, even if recovery of motility is not possible. If speech therapy fails, surgery becomes the treatment of choice. The surgical procedure must be safe and easy to perform, and it has to guarantee good and stable results over time, to avoid the patient undergoing multiple surgeries. In our experience, the best time to perform surgery is 1 year after the onset of paralysis. For the treatment of UVFP, injection laryngoplasty represents a minimally invasive technique in contrast with type I thyroplasty that requires external incision and prolonged surgical time. The injection technique is also rapid and relatively easy to learn, so much so that some authors practice a transcutaneous injection of different materials under local anesthesia.25,26 To obtain long-lasting effects over time, the choice of material is very important. In our experience, PDMS is a good material
FIGURE 8. Spectrogram of word /aiuole/ (P value preop vs postop: <0.01; postop vs long-term FU: 0.2; preop vs long-term FU: <0.01). FU, follow-up; postop, postoperative; preop, preoperative.
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because of its high biocompatibility: in the literature, rare cases of early and late adverse reactions have been reported.27–29 Hyaluronic acid,30 and autologous and bovine collagen31,32 have given good results, but usually require overcorrection and repeated injections33 because they are absorbable materials. Autologous fat34,35 seems to guarantee effects sustainable over 12 months even if it requires a harvesting incision. Recently, calcium hydroxyapatite36 has been introduced for the treatment of UVFP. It allows excellent clinical results to be achieved that remain stable over 12 months37 because it is a slowly reabsorbable material. However, a higher risk of granuloma formation and distant migration compared with PDMS has been reported.38 At our institution, we have used PDMS since 2003 for the treatment of different diseases. These include voice rehabilitation after cordectomy, soft palate paralysis, periprosthetic leakage in total laryngectomy, swallowing disease after partial laryngectomy, as well as vocal cord paralysis. Our previous study4 demonstrated that the injection of PDMS in patients with UVFP guarantees a significant improvement in acoustic, aerodynamic, perceptive, and subjective evaluations with stable results over time (median follow-up 21.7 months). In the literature, no studies on injection laryngoplasty with PDMS have analyzed the long-term outcomes of the procedure; all of the studies previously mentioned have, at most, a mean follow-up of 24 months. The aim of our work was to demonstrate that PDMS can guarantee good long-term functional results. For each patient in this study, follow-up data were collected for at least 3 years after the procedure and mean followup was longer than 70 months. We obtained a significant improvement in the objective (position and edge of vocal fold, MPT, Fo in women, analysis of the spectrogram for the vowel /a/ and the word /aiuole/), perceptive (GIRBAS), and subjective parameters (VHI) after treatment as demonstrated by comparisons between the preoperative and postoperative data. Moreover, our results remained stable over time. In particular, a significant improvement was seen for all of the parameters by comparison between the preoperative and long-term follow-up data, and no statistically significant difference was found between the postoperative and long-term follow-up data. In fact, PDMS is considered to be a nonabsorbable material so it can guarantee stable results and usually no further injections are required. On the other hand, this makes PDMS injection irreversible so we believe that laryngoplasty with PDMS in suspended microlaryngoscopy should be performed under general anesthesia (instead of local anesthesia) because that minimizes the potential for suboptimal placement of the material. A prior accurate VLS examination and an accurate intraoperative evaluation of the anatomical result after injection are mandatory to obtain good functional outcomes. No reabsorption problems, foreign-body reactions, or migration of the PDMS were reported in our series. Clearly, the particle size of the PDMS combined with its surface texture prevents material dislodgement and migration via the lymphatic pathways. An analysis of a larger series should be useful to confirm our results.
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FIGURE 9. GIRBAS scale. P value preop vs postop: <0.01 for all the parameters except S (0.1); postop vs long-term FU: >0.01 for all the parameters; preop vs long-term FU: <0.01 for all the parameters except S (0.07). FU, follow-up; GIRBAS, Grade of Dysphonia, Instability, Roughness, Breathiness, Asthenia, and Strain; postop, postoperative; preop, preoperative.
CONCLUSION Our experience has demonstrated that injection laryngoplasty with PDMS is a minimally invasive procedure for the treatment of UVFP and guarantees stable results over time. Therefore, it represents a good alternative to framework surgery. PDMS seems to be a safe and well-tolerated material because of its high biocompatibility (no perioperative or postoperative complications were reported in our series). Moreover, it is a nonreabsorbable material that allows the objective, perceptive, and subjective outcomes to remain unchanged over time, avoiding repeated treatments. In the end, injection laryngoplasty with PDMS improves the quality of life of patients with UVFP. REFERENCES
FIGURE 10. Global VHI (P value preop vs postop: <0.01; postop vs long-term FU: <0.73; preop vs long-term FU: <0.01). FU, followup; postop, postoperative; preop, preoperative; VHI, Voice Handicap Index.
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