- Email: [email protected]
Treatment Efficacy of Voice Therapy for Vocal Fold Polyps and Factors Predictive of Its Efficacy
ARTICLE IN PRESS Treatment Efficacy of Voice Therapy for Vocal Fold Polyps and Factors Predictive of Its Efficacy 1
Yoon Se Lee, 1Dam Hee Lee, Go-Eun Jeong, Ji Won Kim, Jong-Lyel Roh, Seung-Ho Choi, Sang Yoon Kim, and Soon Yuhl Nam, Seoul, Republic of Korea Summary: Objectives. Vocal fold polyps can be treated with either surgical resection or conservative therapy based on voice therapy. This study was designed to analyze the success rate of voice therapy and identify factors that are predictive of the response to this treatment for vocal fold polyps. Methods. This was a retrospective cohort study of 92 consecutive patients who were diagnosed with vocal fold polyp(s) and received voice therapy. We divided the patients into responding and non-responding groups. We analyzed clinical and voice parameters related to the voice results. Results. After voice therapy, 40 patients showed improved findings and did not undergo surgical treatment. By univariate analysis, female patients (54.9%) and small polyps (56.1%) showed a good response to voice therapy. In multivariate analysis, female sex (odds ratio [OR] = 0.34; confidence interval [CI]: 0.14–0.81, P = 0.01) and small size (OR = 0.15; CI: 0.05–0.47, P < 0.01) were significantly related to a successful voice response. In small polyps, the sessile type of polyp was found to be related to a good response rate (OR = 0.24; CI: 0.11–0.95, P = 0.04). Conclusions. Voice therapy is more effective for small vocal polyps, particularly the sessile type, in female patients. Key Words: Vocal fold polyp–Voice therapy–Type–Size–Predicting factors.
INTRODUCTION A vocal fold polyp is usually a unilateral lesion occurring on the vocal folds and is a common benign laryngeal lesion. Phonotrauma disrupts the microstructure in the superficial layer of the lamina propria (Reinke’s space). This trauma induces local edema, which contributes to subsequent formation of hyalinized stroma, vocal fold polyps, or nodules.1 Repeated injuries to the true vocal fold induce permanent changes and disturbances in the mucosal vibration, and closure of the vocal fold induces voice changes, hoarseness, and increased vocal effort.2 Vocal fold polyps can be observed in various forms, such as sessile versus pedunculated types, and hemorrhagic versus non-hemorrhagic types.3 These distinct features are likely to attribute to different stages or etiologies of polyp formation. Whereas the preferred treatment for vocal fold nodules involves a conservative management approach, vocal fold polyps are treated with either surgical or non-surgical therapies.4,5 Traditionally, surgical therapy, such as resection under the guidance of a laryngomicroscope with mucosa preservation, has been preferred with expected spontaneous healing.5,6 Voice therapy or vocal hygiene education plays an adjunctive role after surgery. Surgery as a treatment modality has the associated risks of general anesthesia and voice aggravation induced by scar formation following surgery. However, current studies have proposed conservative treatments, including voice therapy and vocal hygiene, as acceptable alternative definite therapies to improve voice Accepted for publication February 18, 2016. Conflict of interest: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. From the Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. 1 These authors contributed to this article equally. Address correspondence and reprint requests to Yoon Se Lee and Soon Yuhl Nam, Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea. E-mail: [email protected]; [email protected] Journal of Voice, Vol. ■■, No. ■■, pp. ■■-■■ 0892-1997 © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jvoice.2016.02.014
outcome.7 Although conservative management has a longer duration than surgical treatment and may require guidance from a speech language pathologist, the avoidance of invasive surgical treatment may override those limitations. Definitive treatment guidelines for choosing surgery or conservative management for the treatment of vocal fold polyps have not yet been established. Vocal polyps of a small size, with hemorrhagic features, and occurring in females show a better response to voice therapy or vocal hygiene education.4,8,9 It is necessary to find predicting factors related to effective response to voice therapy when deciding treatment modality for vocal fold polyps. Here, this study was designed to analyze the success rate of voice therapy and determining factors for response to voice therapy for vocal fold polyps. METHODS Participants We performed a retrospective cohort study of consecutive patients who underwent voice therapy from January 2012 to December 2013 at Asan Medical Center, Seoul, Korea. This study was approved by our Institutional Review Board. Ninety-two patients over 18 years old and diagnosed with vocal fold polyp(s) upon videostroboscopy were enrolled for voice therapy. Patients with history of previous treatment (either surgical or nonsurgical therapy), other types of accompanying organic lesions, missing follow-up sessions, or missing medical records were excluded from this study. Voice therapy The same voice therapy protocols were applied to all subjects, including SKMVTT® with laughter, vocal hygiene, and breathing exercises. Two experienced speech language pathologists (D.H.L. and G.J.) with greater than 5 years of experience with voice disorders conducted the therapy. The therapy sessions were carried out by two experienced speech pathologists. The average number of sessions per subject was 3.3, ranging from 1 to 7
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sessions. The average period of therapy was 2 months, ranging from 1 to 4 months. Voice evaluation For perceptual analysis, the GRBAS (Grade, Roughness, Breathiness, Asthenia, and Strain) scale was evaluated by two speech pathologists, blindly. We used a multiple dimensional voice program from a computerized speech lab (CSL model 4500, KayPENTAX Elemetrics, Lincoln Park, NJ) for acoustic evaluation and analyzed jitter, shimmer, and noise-to-harmonic ratio (NHR). For recording the voice, the microphone was placed 10 cm from the patient’s mouth and the patient was instructed to produce a sustained vowel /a/ with a comfortable pitch and loudness three times, the average value of which was subsequently used. For aerodynamic evaluations, a PAS (Phonatory Aerodynamic System Model 6600, KayPENTAX Elemetrics) was used to measure the maximum phonation time (MPT), maximum airflow rate (MFR), and subglottal pressure (Psub). MPT and MFR were measured upon a sustained vowel /a/ as long as possible at a comfortable phonation. The longest value after three trials was subsequently used. To measure subglottic pressures, the patient was instructed to repeat the syllable /pa/ seven times at a single exhalation. A facial mask was firmly fitted and an intraoral tube was placed between the lips. All of these evaluations were conducted by two speech pathologists previously mentioned. When vocal fold polyps were observed using videostroboscopy, we recorded the polyp color, the presence or absence of muscle tension dysphonia (MTD), and the degree of glottal closure using the RLS 9100 device (KayPENTAX Elemetrics). We divided the polyps into three groups according to their size: small if smaller than one fourth of the length of the vocal folds, medium if larger than one fourth and smaller than one third of the vocal folds, or large if larger than one third of the vocal folds.10 Polyps were divided into two groups, “hemorrhagic” and “non-hemorrhagic,” based on color, and also “sessile type” and a “pedunculate type” according to the presence or absence of a tumor stalk (Figure 1). We also divided the subjects into “perfect” and imperfect” groups based on the existence of MTD and the degree of glottal closure. We defined effective or successful voice therapy as a decrease of >50% of the initial polyp size without necessity of surgical resection. Statistical analysis Statistical analyses were performed using IBM SPSS software (version 21.0 for Windows; IBM Corp., Armonk, NY). We used the chi-square test and the Student’s t-test to compare subjects who showed a decrease in size of the polyp but who did not show meaningful decrease. To investigate factors that influence the effectiveness of voice therapy, we used logistic regression to compare subgroups within the “small” group. The t-test and logistic regression analysis were performed with a statistical significance level of 0.05. RESULTS The age range of the subjects (41 males and 51 females) was 22–72 years, with an average age of 51. After voice therapy, 40 patients showed polyp shrinkage more than 50% and did not
FIGURE 1. Classification of vocal fold polyp according to the stalk: (A) sessile type and (B) pedunculate type.
undergo surgical treatment, whereas 52 patients showed no significant change and 41 patients of them (78.8%) underwent laryngomicroscopic surgery. By univariate analysis, female patients (n = 28, 54.9%) presented a good response to voice therapy compared with male patients (n = 12, 29.3%, P = 0.01; Table 1). Age and smoking were not related to the response to voice therapy. We reviewed the videostroboscopic findings for polyp size, color, and type, and accompanying MTD and glottal closure. Sixty-six patients had a small polyp, whereas 14 and 12 patients showed medium and large polyps, respectively. Small polyps (n = 37, 56.1%) responded to voice therapy significantly better than medium- (n = 2, 14.3%) or large-sized polyps (n = 1, 8.3%, P < 0.01). Polyp color and type, accompanying MTD, and glottal closure were not found to be related to the voice therapy response rate. There was no difference found either in the average GRBAS scale, acoustic parameters (jitter, shimmer, and NHR), or aerodynamic parameters (MPT, MFR, and Psub) between responders and non-responders before treatment (Table 2). The responsive patients were also more likely to have higher breathiness than the cases in the non-response group (P = 0.06). In multivariate analysis, female sex was a significant factor indicative of a positive response to voice therapy (odds ratio [OR] = 0.34; confidence interval [CI]: 0.14–0.81, P = 0.01;
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Conservative Care for Vocal Fold Polyps
TABLE 1. Demographic Findings and Univariate Analysis of Enrolled Patients Variables Age Gender Smoking Size
Color Type MTD Glottal closure
≥60 years <60 years Male Female (+) (−) Small Medium Large Hemorrhagic Non-hemorrhagic Sessile Pedunculated (+) (−) Complete Incomplete
Response (+) n (%)
Response (−) n (%)
8 (20) 32 (80) 12 (30) 28 (70) 4 (10) 36 (90) 37 (92.5) 2 (5) 1 (2.5) 18 (45) 22 (55) 14 (35) 26 (65.0) 28 (70) 12 (30) 24 (60) 16 (40)
12 (23.1) 40 (76.9) 29 (55.8) 23 (44.2) 4 (7.7) 48 (82.3) 29 (55.8) 12 (23.1) 11 (21.1) 28 (53.8) 24 (46.2) 12 (23.1) 40 (76.9) 22 (42.3) 18 (34.6) 30 (57.7) 22 (42.3)
P 0.70 0.01 0.69 <0.01
0.40 0.20 0.64 0.82
Abbreviation: MTD, muscle tension dysphonia.
TABLE 2. Comparison of Average of Each Voice Parameter Between Two Groups Parameters Perceptual evaluation
Acoustic analysis
Aerodynamic analysis
G R B A S Jitter Shimmer NHR MPT MFR Psub
Response (−)
Response (+)
P
1.45 ± 0.55 1.17 ± 0.78 1 ± 0.71 0.27 ± 0.50 0.52 ± 0.64 1.87 ± 1.92 4.64 ± 4.12 0.30 ± 0.96 12.25 ± 5.31 108.75 ± 85.73 6.78 ± 2.21
1.38 ± 0.56 1.03 ± 0.65 1.17 ± 1.42 0.07 ± 0.26 0.46 ± 0.64 1.79 ± 1.46 4.10 ± 2.73 3.02 ± 20.78 12.35 ± 5.49 140.19 ± 88.03 7.42 ± 1.99
0.82 0.43 0.06 0.58 0.70 0.82 0.45 0.20 0.93 0.08 0.15
Abbreviations: MFR, maximum airflow rate; MPT, maximum phonation time; NHR, noise-to-harmonic ratio.
Table 3). A small polyp size was another significant indicator of a positive response to voice therapy (OR = 0.15; CI: 0.05– 0.47, P < 0.01). No other factors were found to be associated with the response rate to voice therapy. Most of our study patients who had a good response to voice therapy had a small polyp (92.5%), and we analyzed the predictive factors for this response in this subgroup (Table 4). The type of polyp was found to be significantly related to the response to voice therapy among our small polyp patients. Sessiletype polyps (80%, n = 12) showed a better response than the nonsessile type (49%, n = 25, P = 0.03). Female patients appeared to be likely to respond, but not significantly (P = 0.13). There was no difference in the average GRBAS scale, acoustic parameters (jitter, shimmer, and NHR), or aerodynamic parameters (MPT, MFR, and Psub) between responders and non-responders. By multivariate analysis, the sessile type of polyp was shown
TABLE 3. Multivariate Analysis of Factors Affecting Response to Voice Therapy
Parameters Gender Size Type MTD
Confidence Interval
β
Odds Ratio
Lower
Upper
P
−1.07 −1.91 −0.85 0.21
0.34 0.15 0.55 1.23
0.14 0.05 0.22 0.51
0.81 0.47 1.392 2.99
0.01 <0.01 0.21 0.84
Abbreviation: MTD, muscle tension dysphonia.
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TABLE 4. Demographic Findings and Univariate Analysis of Patients With Small Polyp Variables ≥60 years <60 years Male Female (+) (−) Hemorrhagic Non-hemorrhagic Sessile Pedunculated (+) (−) Complete Incomplete
Age Gender Smoking Color Type MTD Glottal closure
Response (+) n (%)
Response (−) n (%)
8 (20) 32 (80) 10 (30) 27 (70) 3 (10) 34 (90) 17 (45.9) 20 (54.0) 12 (35) 25 (65.0) 26 (70) 11 (30) 22 (60) 15 (40)
12 (23.1) 40 (76.9) 13 (55.8) 16 (44.2) 1 (7.7) 28 (82.3) 14 (53.8) 15 (46.2) 3 (23.1) 26 (76.9) 20 (42.3) 9 (34.6) 18 (57.7) 11 (42.3)
P 0.70 0.13 0.43 0.52 0.03 0.56 0.51
Abbreviation: MTD, muscle tension dysphonia.
to be associated with a better response rate (OR = 0.24; CI: 0.11– 0.95, P = 0.04; Table 5). DISCUSSION This study evaluated the efficacy of voice therapy for vocal fold polyp. Our protocol for vocal fold polyp prefers voice therapy for vocal fold polyp as an initial approach to avoid unnecessary surgical resection.11 In our present study, 40 of the enrolled patients (43.8 %) improved after they received voice therapy. Patients with small polyps and female patients showed the most effective response to voice therapy. Among our cases of small polyps, the sessile type rather than the pedunculated type was found to be a good indicator for effective voice therapy. There have been some reports regarding the efficiency of conservative treatments for vocal fold polyps based on voice therapy. Although it has longer treatment duration than surgical therapy, voice therapy has been reported to improve voice outcomes by 20%–49%.9,12 Even a hemorrhagic vocal fold polyp can resolve in 56% of patients who undergo conservative management.4 Patient gender, tumor size, tumor type, MTD, and glottal closure have been reported to affect the success rate of voice therapy in various studies. Among these prognostic factors, female sex and small-sized polyps are important determining factors for the efficacy of voice therapy. A small-sized polyp may be in an im-
TABLE 5. Multivariate Analysis of Factors Affecting Response to Voice Therapy in Patients With Small Polyp
Parameters
β
Gender 1.04 Type (pedunculated −1.42 vs sessile)
Confidence Interval Odds Ratio Lower Upper
P
−0.76 0.11
0.25 0.04
2.85 0.24
3.11 0.95
mature state or may be confused with a nodule. This confusion may affect treatment outcomes in patients with small polyps.13 The low rate of voice abuse in female patients compared with male patients is related to the good response to voice therapy in women. Smoking has been reported as another good indicator of the likely success of voice therapy in other reports.9 Smoking may induce repeated inflammation, hinder the normal wound healing process, and cause irreversible change.14,15 However, smoking was not found to be related to treatment outcomes in our current study, and the low proportion of smokers in our study population (n = 8) might have affected our analysis. We found no definitive voice parameters that are predictors of voice therapy outcomes, similar to other reports. We analyzed predictive factors for small polyps because a small lesion size is the most commonly alleged positive indicator of voice therapy outcomes in vocal fold polyp patients. Based on our current observations, we believe that the sessile polyp type is a good candidate for voice therapy if the practitioner can discriminate the lesion well from an intracordal cyst. Although excision of a vocal fold polyp is a preferred intervention by many surgeons, a treatment protocol for vocal fold nodules or polyps at our institute involves a trial of voice therapy, including vocal hygiene, in these cases. Considering that some lesions, especially hemorrhagic type polyps, resolve spontaneously without any intervention,4 and voice therapy can also help reduce the size of a vocal fold polyp, we established a protocol that comprises an initially conservative management approach for vocal fold polyps and nodules. Given that a vocal fold polyp arises from the compensatory hyperfunction of intralaryngeal muscles to maintain phonation and phonatory effort, and aggravates the symptoms and signs of vocal fold lesions, behavioral intervention is vital to escape this vicious cycle.16 Voice abuse and frequent throat clearing are observed more frequently in patients with vocal fold polyps, compared with the normal population.12,17 Theoretically, voice therapy including vocal hygiene is a useful method to alleviate vocal fold
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Conservative Care for Vocal Fold Polyps
polyps. Thus, voice therapy designed to induce behavioral changes may eliminate predisposing factors for vocal fold polyps, such as excessive phonatory efforts and voice abuse. In addition, sufficient hydration and lubrication helps to maintain moisture in the larynx and to decrease abnormal secretion, which enables the mucosa to vibrate comfortably upon initiating phonation and protect the vocal fold from injury.16 Respiratory and phonatory exercises prevent exaggerated vocal fold contact and induce relaxed phonation.18 Based on these ideas and the results from our current study, we contend that voice therapy is a useful method for the primary treatment of a vocal fold polyp. However, an adjuvant role of voice therapy after surgical resection to prevent recurrence of a vocal fold polyp is not well established. Office-based steroid injection and surgical resection are alternative and available methods for the treatment of vocal fold polyps.19,20 However, the technical difficulties in avoiding either muscular atrophy induced by deep injection or mucosal injury induced by inadequate resection are the main limitations of these approaches. Compared with those procedures, voice therapy is a far more readily accessible treatment modality. Accompanying MTD has been reported to ameliorate the efficacy of voice therapy,8 but we did not obtain similar results in our current analyses. We speculated that other functional dysphonia predisposing the onset of vocal fold polyps would have a negative effect on voice therapy. However, the voice therapy technique used in our current patient series probably alleviated the MTD, and a simultaneous vocal fold polyp with MTD was not likely to affect the treatment results. Other factors influencing treatment results such as an accompanying comorbidity, for example laryngopharyngeal reflux, and treatment duration were not considered in our present study. In addition, we defined a successful treatment as a size reduction of more than 50%, which is somewhat arbitrary. We thought that the size improvement would be evident and symptom was also ameliorated according to this size reduction. These were the main limitations of this retrospective study. As most of our enrolled patients had a small-sized polyp (71.7%), voice therapy was applied to these patients as an initial treatment approach. Most of our patients with a large vocal fold polyp were probably treated with surgical resection. The therapeutic basis for voice therapy for a large polyp was not clearly elucidated by our present analyses. Moreover, because we had no data on patient compliance with the voice therapy program, a further study of large polyps may show different results. Regardless of the polyp size, treatment results of surgical resection for vocal fold polyp would be better than voice therapy. But voice therapy for vocal fold polyps is an alternate option for patients who are intolerable to general anesthesia or favor non-surgical treatment. CONCLUSIONS Voice therapy is a feasible treatment approach for a vocal fold polyp. Female patients and small vocal fold polyps are posi-
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tive indicators for voice therapy. In small-sized polyps, in particular, the sessile type responds to voice therapy more frequently compared with the pedunculated type. These factors should be considered when choosing a treatment modality for a vocal fold polyp, and the findings of our current study may help such patients to avoid unnecessary surgical resection and instead undergo voice therapy in the future. Acknowledgment This study was supported by a grant (2014-620) from the Asan Institute for Life Sciences, Asan Medical Center, Seoul, Korea. REFERENCES 1. Altman KW. Vocal fold masses. Otolaryngol Clin North Am. 2007;40:1091– 1108. 2. Kotby MN, Nassar AM, Seif EI, et al. Ultrastructural features of vocal fold nodules and polyps. Acta Otolaryngol. 1988;105:477–482. 3. Aronson AE, Bless D. Clinical Voice Disorders. New York: Thieme; 2011. 4. Klein AM, Lehmann M, Hapner ER, et al. Spontaneous resolution of hemorrhagic polyps of the true vocal fold. J Voice. 2009;23:132–135. 5. Zeitels SM, Hillman RE, Desloge R, et al. Phonomicrosurgery in singers and performing artists: treatment outcomes, management theories, and future directions. Ann Otol Rhinol Laryngol Suppl. 2002;190:21–40. 6. Courey MS, Garrett CG, Ossoff RH. Medial microflap for excision of benign vocal fold lesions. Laryngoscope. 1997;107:340–344. 7. Sulica L, Behrman A. Management of benign vocal fold lesions: a survey of current opinion and practice. Ann Otol Rhinol Laryngol. 2003;112:827– 833. 8. Cho KJ, Nam IC, Hwang YS, et al. Analysis of factors influencing voice quality and therapeutic approaches in vocal polyp patients. Eur Arch Otorhinolaryngol. 2011;268:1321–1327. 9. Yun YS, Kim MB, Son YI. The effect of vocal hygiene education for patients with vocal polyp. Otolaryngol Head Neck Surg. 2007;137:569–575. 10. Garrett CG, Francis DO. Is surgery necessary for all vocal fold polyps? Laryngoscope. 2014;124:363–364. 11. Johns MM. Update on the etiology, diagnosis, and treatment of vocal fold nodules, polyps, and cysts. Curr Opin Otolaryngol Head Neck Surg. 2003;11:456–461. 12. Cohen SM, Garrett CG. Utility of voice therapy in the management of vocal fold polyps and cysts. Otolaryngol Head Neck Surg. 2007;136:742–746. 13. Srirompotong S, Saeseow P, Vatanasapt P. Small vocal cord polyps: completely resolved with conservative treatment. Southeast Asian J Trop Med Public Health. 2004;35:169–171. 14. Auerbach O, Hammond EC, Garfinkel L. Histologic changes in the larynx in relation to smoking habits. Cancer. 1970;25:92–104. 15. Kambicˇ V, Radšel Z, Žargi M, et al. Vocal cord polyps: incidence, histology and pathogenesis. J Laryngol Otol. 1981;95:609–618. 16. Verdolini K, DeVore K, McCoy S, et al. National Center for Voice and Speech’s Guide to Vocology. Iowa City: University of Iowa; 1998. 17. Holmberg EB, Hillman RE, Hammarberg B, et al. Efficacy of a behaviorally based voice therapy protocol for vocal nodules. J Voice. 2001;15:395–412. 18. Kim ST, Jeong GE, Kim SY, et al. The effect of voice therapy in vocal polyp patients. J Korean Soc Speech Sci. 2009;1:43–49. 19. Wang CT, Huang TW, Liao LJ, et al. Office-based potassium titanyl phosphate laser-assisted endoscopic vocal polypectomy. JAMA Otolaryngol Head Neck Surg. 2013;139:610–616. 20. Wang CT, Liao LJ, Cheng PW, et al. Intralesional steroid injection for benign vocal fold disorders: a systematic review and meta-analysis. Laryngoscope. 2013;123:197–203.
Yoon Se Lee, 1Dam Hee Lee, Go-Eun Jeong, Ji Won Kim, Jong-Lyel Roh, Seung-Ho Choi, Sang Yoon Kim, and Soon Yuhl Nam, Seoul, Republic of Korea Summary: Objectives. Vocal fold polyps can be treated with either surgical resection or conservative therapy based on voice therapy. This study was designed to analyze the success rate of voice therapy and identify factors that are predictive of the response to this treatment for vocal fold polyps. Methods. This was a retrospective cohort study of 92 consecutive patients who were diagnosed with vocal fold polyp(s) and received voice therapy. We divided the patients into responding and non-responding groups. We analyzed clinical and voice parameters related to the voice results. Results. After voice therapy, 40 patients showed improved findings and did not undergo surgical treatment. By univariate analysis, female patients (54.9%) and small polyps (56.1%) showed a good response to voice therapy. In multivariate analysis, female sex (odds ratio [OR] = 0.34; confidence interval [CI]: 0.14–0.81, P = 0.01) and small size (OR = 0.15; CI: 0.05–0.47, P < 0.01) were significantly related to a successful voice response. In small polyps, the sessile type of polyp was found to be related to a good response rate (OR = 0.24; CI: 0.11–0.95, P = 0.04). Conclusions. Voice therapy is more effective for small vocal polyps, particularly the sessile type, in female patients. Key Words: Vocal fold polyp–Voice therapy–Type–Size–Predicting factors.
INTRODUCTION A vocal fold polyp is usually a unilateral lesion occurring on the vocal folds and is a common benign laryngeal lesion. Phonotrauma disrupts the microstructure in the superficial layer of the lamina propria (Reinke’s space). This trauma induces local edema, which contributes to subsequent formation of hyalinized stroma, vocal fold polyps, or nodules.1 Repeated injuries to the true vocal fold induce permanent changes and disturbances in the mucosal vibration, and closure of the vocal fold induces voice changes, hoarseness, and increased vocal effort.2 Vocal fold polyps can be observed in various forms, such as sessile versus pedunculated types, and hemorrhagic versus non-hemorrhagic types.3 These distinct features are likely to attribute to different stages or etiologies of polyp formation. Whereas the preferred treatment for vocal fold nodules involves a conservative management approach, vocal fold polyps are treated with either surgical or non-surgical therapies.4,5 Traditionally, surgical therapy, such as resection under the guidance of a laryngomicroscope with mucosa preservation, has been preferred with expected spontaneous healing.5,6 Voice therapy or vocal hygiene education plays an adjunctive role after surgery. Surgery as a treatment modality has the associated risks of general anesthesia and voice aggravation induced by scar formation following surgery. However, current studies have proposed conservative treatments, including voice therapy and vocal hygiene, as acceptable alternative definite therapies to improve voice Accepted for publication February 18, 2016. Conflict of interest: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. From the Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. 1 These authors contributed to this article equally. Address correspondence and reprint requests to Yoon Se Lee and Soon Yuhl Nam, Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea. E-mail: [email protected]; [email protected] Journal of Voice, Vol. ■■, No. ■■, pp. ■■-■■ 0892-1997 © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jvoice.2016.02.014
outcome.7 Although conservative management has a longer duration than surgical treatment and may require guidance from a speech language pathologist, the avoidance of invasive surgical treatment may override those limitations. Definitive treatment guidelines for choosing surgery or conservative management for the treatment of vocal fold polyps have not yet been established. Vocal polyps of a small size, with hemorrhagic features, and occurring in females show a better response to voice therapy or vocal hygiene education.4,8,9 It is necessary to find predicting factors related to effective response to voice therapy when deciding treatment modality for vocal fold polyps. Here, this study was designed to analyze the success rate of voice therapy and determining factors for response to voice therapy for vocal fold polyps. METHODS Participants We performed a retrospective cohort study of consecutive patients who underwent voice therapy from January 2012 to December 2013 at Asan Medical Center, Seoul, Korea. This study was approved by our Institutional Review Board. Ninety-two patients over 18 years old and diagnosed with vocal fold polyp(s) upon videostroboscopy were enrolled for voice therapy. Patients with history of previous treatment (either surgical or nonsurgical therapy), other types of accompanying organic lesions, missing follow-up sessions, or missing medical records were excluded from this study. Voice therapy The same voice therapy protocols were applied to all subjects, including SKMVTT® with laughter, vocal hygiene, and breathing exercises. Two experienced speech language pathologists (D.H.L. and G.J.) with greater than 5 years of experience with voice disorders conducted the therapy. The therapy sessions were carried out by two experienced speech pathologists. The average number of sessions per subject was 3.3, ranging from 1 to 7
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sessions. The average period of therapy was 2 months, ranging from 1 to 4 months. Voice evaluation For perceptual analysis, the GRBAS (Grade, Roughness, Breathiness, Asthenia, and Strain) scale was evaluated by two speech pathologists, blindly. We used a multiple dimensional voice program from a computerized speech lab (CSL model 4500, KayPENTAX Elemetrics, Lincoln Park, NJ) for acoustic evaluation and analyzed jitter, shimmer, and noise-to-harmonic ratio (NHR). For recording the voice, the microphone was placed 10 cm from the patient’s mouth and the patient was instructed to produce a sustained vowel /a/ with a comfortable pitch and loudness three times, the average value of which was subsequently used. For aerodynamic evaluations, a PAS (Phonatory Aerodynamic System Model 6600, KayPENTAX Elemetrics) was used to measure the maximum phonation time (MPT), maximum airflow rate (MFR), and subglottal pressure (Psub). MPT and MFR were measured upon a sustained vowel /a/ as long as possible at a comfortable phonation. The longest value after three trials was subsequently used. To measure subglottic pressures, the patient was instructed to repeat the syllable /pa/ seven times at a single exhalation. A facial mask was firmly fitted and an intraoral tube was placed between the lips. All of these evaluations were conducted by two speech pathologists previously mentioned. When vocal fold polyps were observed using videostroboscopy, we recorded the polyp color, the presence or absence of muscle tension dysphonia (MTD), and the degree of glottal closure using the RLS 9100 device (KayPENTAX Elemetrics). We divided the polyps into three groups according to their size: small if smaller than one fourth of the length of the vocal folds, medium if larger than one fourth and smaller than one third of the vocal folds, or large if larger than one third of the vocal folds.10 Polyps were divided into two groups, “hemorrhagic” and “non-hemorrhagic,” based on color, and also “sessile type” and a “pedunculate type” according to the presence or absence of a tumor stalk (Figure 1). We also divided the subjects into “perfect” and imperfect” groups based on the existence of MTD and the degree of glottal closure. We defined effective or successful voice therapy as a decrease of >50% of the initial polyp size without necessity of surgical resection. Statistical analysis Statistical analyses were performed using IBM SPSS software (version 21.0 for Windows; IBM Corp., Armonk, NY). We used the chi-square test and the Student’s t-test to compare subjects who showed a decrease in size of the polyp but who did not show meaningful decrease. To investigate factors that influence the effectiveness of voice therapy, we used logistic regression to compare subgroups within the “small” group. The t-test and logistic regression analysis were performed with a statistical significance level of 0.05. RESULTS The age range of the subjects (41 males and 51 females) was 22–72 years, with an average age of 51. After voice therapy, 40 patients showed polyp shrinkage more than 50% and did not
FIGURE 1. Classification of vocal fold polyp according to the stalk: (A) sessile type and (B) pedunculate type.
undergo surgical treatment, whereas 52 patients showed no significant change and 41 patients of them (78.8%) underwent laryngomicroscopic surgery. By univariate analysis, female patients (n = 28, 54.9%) presented a good response to voice therapy compared with male patients (n = 12, 29.3%, P = 0.01; Table 1). Age and smoking were not related to the response to voice therapy. We reviewed the videostroboscopic findings for polyp size, color, and type, and accompanying MTD and glottal closure. Sixty-six patients had a small polyp, whereas 14 and 12 patients showed medium and large polyps, respectively. Small polyps (n = 37, 56.1%) responded to voice therapy significantly better than medium- (n = 2, 14.3%) or large-sized polyps (n = 1, 8.3%, P < 0.01). Polyp color and type, accompanying MTD, and glottal closure were not found to be related to the voice therapy response rate. There was no difference found either in the average GRBAS scale, acoustic parameters (jitter, shimmer, and NHR), or aerodynamic parameters (MPT, MFR, and Psub) between responders and non-responders before treatment (Table 2). The responsive patients were also more likely to have higher breathiness than the cases in the non-response group (P = 0.06). In multivariate analysis, female sex was a significant factor indicative of a positive response to voice therapy (odds ratio [OR] = 0.34; confidence interval [CI]: 0.14–0.81, P = 0.01;
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Conservative Care for Vocal Fold Polyps
TABLE 1. Demographic Findings and Univariate Analysis of Enrolled Patients Variables Age Gender Smoking Size
Color Type MTD Glottal closure
≥60 years <60 years Male Female (+) (−) Small Medium Large Hemorrhagic Non-hemorrhagic Sessile Pedunculated (+) (−) Complete Incomplete
Response (+) n (%)
Response (−) n (%)
8 (20) 32 (80) 12 (30) 28 (70) 4 (10) 36 (90) 37 (92.5) 2 (5) 1 (2.5) 18 (45) 22 (55) 14 (35) 26 (65.0) 28 (70) 12 (30) 24 (60) 16 (40)
12 (23.1) 40 (76.9) 29 (55.8) 23 (44.2) 4 (7.7) 48 (82.3) 29 (55.8) 12 (23.1) 11 (21.1) 28 (53.8) 24 (46.2) 12 (23.1) 40 (76.9) 22 (42.3) 18 (34.6) 30 (57.7) 22 (42.3)
P 0.70 0.01 0.69 <0.01
0.40 0.20 0.64 0.82
Abbreviation: MTD, muscle tension dysphonia.
TABLE 2. Comparison of Average of Each Voice Parameter Between Two Groups Parameters Perceptual evaluation
Acoustic analysis
Aerodynamic analysis
G R B A S Jitter Shimmer NHR MPT MFR Psub
Response (−)
Response (+)
P
1.45 ± 0.55 1.17 ± 0.78 1 ± 0.71 0.27 ± 0.50 0.52 ± 0.64 1.87 ± 1.92 4.64 ± 4.12 0.30 ± 0.96 12.25 ± 5.31 108.75 ± 85.73 6.78 ± 2.21
1.38 ± 0.56 1.03 ± 0.65 1.17 ± 1.42 0.07 ± 0.26 0.46 ± 0.64 1.79 ± 1.46 4.10 ± 2.73 3.02 ± 20.78 12.35 ± 5.49 140.19 ± 88.03 7.42 ± 1.99
0.82 0.43 0.06 0.58 0.70 0.82 0.45 0.20 0.93 0.08 0.15
Abbreviations: MFR, maximum airflow rate; MPT, maximum phonation time; NHR, noise-to-harmonic ratio.
Table 3). A small polyp size was another significant indicator of a positive response to voice therapy (OR = 0.15; CI: 0.05– 0.47, P < 0.01). No other factors were found to be associated with the response rate to voice therapy. Most of our study patients who had a good response to voice therapy had a small polyp (92.5%), and we analyzed the predictive factors for this response in this subgroup (Table 4). The type of polyp was found to be significantly related to the response to voice therapy among our small polyp patients. Sessiletype polyps (80%, n = 12) showed a better response than the nonsessile type (49%, n = 25, P = 0.03). Female patients appeared to be likely to respond, but not significantly (P = 0.13). There was no difference in the average GRBAS scale, acoustic parameters (jitter, shimmer, and NHR), or aerodynamic parameters (MPT, MFR, and Psub) between responders and non-responders. By multivariate analysis, the sessile type of polyp was shown
TABLE 3. Multivariate Analysis of Factors Affecting Response to Voice Therapy
Parameters Gender Size Type MTD
Confidence Interval
β
Odds Ratio
Lower
Upper
P
−1.07 −1.91 −0.85 0.21
0.34 0.15 0.55 1.23
0.14 0.05 0.22 0.51
0.81 0.47 1.392 2.99
0.01 <0.01 0.21 0.84
Abbreviation: MTD, muscle tension dysphonia.
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TABLE 4. Demographic Findings and Univariate Analysis of Patients With Small Polyp Variables ≥60 years <60 years Male Female (+) (−) Hemorrhagic Non-hemorrhagic Sessile Pedunculated (+) (−) Complete Incomplete
Age Gender Smoking Color Type MTD Glottal closure
Response (+) n (%)
Response (−) n (%)
8 (20) 32 (80) 10 (30) 27 (70) 3 (10) 34 (90) 17 (45.9) 20 (54.0) 12 (35) 25 (65.0) 26 (70) 11 (30) 22 (60) 15 (40)
12 (23.1) 40 (76.9) 13 (55.8) 16 (44.2) 1 (7.7) 28 (82.3) 14 (53.8) 15 (46.2) 3 (23.1) 26 (76.9) 20 (42.3) 9 (34.6) 18 (57.7) 11 (42.3)
P 0.70 0.13 0.43 0.52 0.03 0.56 0.51
Abbreviation: MTD, muscle tension dysphonia.
to be associated with a better response rate (OR = 0.24; CI: 0.11– 0.95, P = 0.04; Table 5). DISCUSSION This study evaluated the efficacy of voice therapy for vocal fold polyp. Our protocol for vocal fold polyp prefers voice therapy for vocal fold polyp as an initial approach to avoid unnecessary surgical resection.11 In our present study, 40 of the enrolled patients (43.8 %) improved after they received voice therapy. Patients with small polyps and female patients showed the most effective response to voice therapy. Among our cases of small polyps, the sessile type rather than the pedunculated type was found to be a good indicator for effective voice therapy. There have been some reports regarding the efficiency of conservative treatments for vocal fold polyps based on voice therapy. Although it has longer treatment duration than surgical therapy, voice therapy has been reported to improve voice outcomes by 20%–49%.9,12 Even a hemorrhagic vocal fold polyp can resolve in 56% of patients who undergo conservative management.4 Patient gender, tumor size, tumor type, MTD, and glottal closure have been reported to affect the success rate of voice therapy in various studies. Among these prognostic factors, female sex and small-sized polyps are important determining factors for the efficacy of voice therapy. A small-sized polyp may be in an im-
TABLE 5. Multivariate Analysis of Factors Affecting Response to Voice Therapy in Patients With Small Polyp
Parameters
β
Gender 1.04 Type (pedunculated −1.42 vs sessile)
Confidence Interval Odds Ratio Lower Upper
P
−0.76 0.11
0.25 0.04
2.85 0.24
3.11 0.95
mature state or may be confused with a nodule. This confusion may affect treatment outcomes in patients with small polyps.13 The low rate of voice abuse in female patients compared with male patients is related to the good response to voice therapy in women. Smoking has been reported as another good indicator of the likely success of voice therapy in other reports.9 Smoking may induce repeated inflammation, hinder the normal wound healing process, and cause irreversible change.14,15 However, smoking was not found to be related to treatment outcomes in our current study, and the low proportion of smokers in our study population (n = 8) might have affected our analysis. We found no definitive voice parameters that are predictors of voice therapy outcomes, similar to other reports. We analyzed predictive factors for small polyps because a small lesion size is the most commonly alleged positive indicator of voice therapy outcomes in vocal fold polyp patients. Based on our current observations, we believe that the sessile polyp type is a good candidate for voice therapy if the practitioner can discriminate the lesion well from an intracordal cyst. Although excision of a vocal fold polyp is a preferred intervention by many surgeons, a treatment protocol for vocal fold nodules or polyps at our institute involves a trial of voice therapy, including vocal hygiene, in these cases. Considering that some lesions, especially hemorrhagic type polyps, resolve spontaneously without any intervention,4 and voice therapy can also help reduce the size of a vocal fold polyp, we established a protocol that comprises an initially conservative management approach for vocal fold polyps and nodules. Given that a vocal fold polyp arises from the compensatory hyperfunction of intralaryngeal muscles to maintain phonation and phonatory effort, and aggravates the symptoms and signs of vocal fold lesions, behavioral intervention is vital to escape this vicious cycle.16 Voice abuse and frequent throat clearing are observed more frequently in patients with vocal fold polyps, compared with the normal population.12,17 Theoretically, voice therapy including vocal hygiene is a useful method to alleviate vocal fold
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Conservative Care for Vocal Fold Polyps
polyps. Thus, voice therapy designed to induce behavioral changes may eliminate predisposing factors for vocal fold polyps, such as excessive phonatory efforts and voice abuse. In addition, sufficient hydration and lubrication helps to maintain moisture in the larynx and to decrease abnormal secretion, which enables the mucosa to vibrate comfortably upon initiating phonation and protect the vocal fold from injury.16 Respiratory and phonatory exercises prevent exaggerated vocal fold contact and induce relaxed phonation.18 Based on these ideas and the results from our current study, we contend that voice therapy is a useful method for the primary treatment of a vocal fold polyp. However, an adjuvant role of voice therapy after surgical resection to prevent recurrence of a vocal fold polyp is not well established. Office-based steroid injection and surgical resection are alternative and available methods for the treatment of vocal fold polyps.19,20 However, the technical difficulties in avoiding either muscular atrophy induced by deep injection or mucosal injury induced by inadequate resection are the main limitations of these approaches. Compared with those procedures, voice therapy is a far more readily accessible treatment modality. Accompanying MTD has been reported to ameliorate the efficacy of voice therapy,8 but we did not obtain similar results in our current analyses. We speculated that other functional dysphonia predisposing the onset of vocal fold polyps would have a negative effect on voice therapy. However, the voice therapy technique used in our current patient series probably alleviated the MTD, and a simultaneous vocal fold polyp with MTD was not likely to affect the treatment results. Other factors influencing treatment results such as an accompanying comorbidity, for example laryngopharyngeal reflux, and treatment duration were not considered in our present study. In addition, we defined a successful treatment as a size reduction of more than 50%, which is somewhat arbitrary. We thought that the size improvement would be evident and symptom was also ameliorated according to this size reduction. These were the main limitations of this retrospective study. As most of our enrolled patients had a small-sized polyp (71.7%), voice therapy was applied to these patients as an initial treatment approach. Most of our patients with a large vocal fold polyp were probably treated with surgical resection. The therapeutic basis for voice therapy for a large polyp was not clearly elucidated by our present analyses. Moreover, because we had no data on patient compliance with the voice therapy program, a further study of large polyps may show different results. Regardless of the polyp size, treatment results of surgical resection for vocal fold polyp would be better than voice therapy. But voice therapy for vocal fold polyps is an alternate option for patients who are intolerable to general anesthesia or favor non-surgical treatment. CONCLUSIONS Voice therapy is a feasible treatment approach for a vocal fold polyp. Female patients and small vocal fold polyps are posi-
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tive indicators for voice therapy. In small-sized polyps, in particular, the sessile type responds to voice therapy more frequently compared with the pedunculated type. These factors should be considered when choosing a treatment modality for a vocal fold polyp, and the findings of our current study may help such patients to avoid unnecessary surgical resection and instead undergo voice therapy in the future. Acknowledgment This study was supported by a grant (2014-620) from the Asan Institute for Life Sciences, Asan Medical Center, Seoul, Korea. REFERENCES 1. Altman KW. Vocal fold masses. Otolaryngol Clin North Am. 2007;40:1091– 1108. 2. Kotby MN, Nassar AM, Seif EI, et al. Ultrastructural features of vocal fold nodules and polyps. Acta Otolaryngol. 1988;105:477–482. 3. Aronson AE, Bless D. Clinical Voice Disorders. New York: Thieme; 2011. 4. Klein AM, Lehmann M, Hapner ER, et al. Spontaneous resolution of hemorrhagic polyps of the true vocal fold. J Voice. 2009;23:132–135. 5. Zeitels SM, Hillman RE, Desloge R, et al. Phonomicrosurgery in singers and performing artists: treatment outcomes, management theories, and future directions. Ann Otol Rhinol Laryngol Suppl. 2002;190:21–40. 6. Courey MS, Garrett CG, Ossoff RH. Medial microflap for excision of benign vocal fold lesions. Laryngoscope. 1997;107:340–344. 7. Sulica L, Behrman A. Management of benign vocal fold lesions: a survey of current opinion and practice. Ann Otol Rhinol Laryngol. 2003;112:827– 833. 8. Cho KJ, Nam IC, Hwang YS, et al. Analysis of factors influencing voice quality and therapeutic approaches in vocal polyp patients. Eur Arch Otorhinolaryngol. 2011;268:1321–1327. 9. Yun YS, Kim MB, Son YI. The effect of vocal hygiene education for patients with vocal polyp. Otolaryngol Head Neck Surg. 2007;137:569–575. 10. Garrett CG, Francis DO. Is surgery necessary for all vocal fold polyps? Laryngoscope. 2014;124:363–364. 11. Johns MM. Update on the etiology, diagnosis, and treatment of vocal fold nodules, polyps, and cysts. Curr Opin Otolaryngol Head Neck Surg. 2003;11:456–461. 12. Cohen SM, Garrett CG. Utility of voice therapy in the management of vocal fold polyps and cysts. Otolaryngol Head Neck Surg. 2007;136:742–746. 13. Srirompotong S, Saeseow P, Vatanasapt P. Small vocal cord polyps: completely resolved with conservative treatment. Southeast Asian J Trop Med Public Health. 2004;35:169–171. 14. Auerbach O, Hammond EC, Garfinkel L. Histologic changes in the larynx in relation to smoking habits. Cancer. 1970;25:92–104. 15. Kambicˇ V, Radšel Z, Žargi M, et al. Vocal cord polyps: incidence, histology and pathogenesis. J Laryngol Otol. 1981;95:609–618. 16. Verdolini K, DeVore K, McCoy S, et al. National Center for Voice and Speech’s Guide to Vocology. Iowa City: University of Iowa; 1998. 17. Holmberg EB, Hillman RE, Hammarberg B, et al. Efficacy of a behaviorally based voice therapy protocol for vocal nodules. J Voice. 2001;15:395–412. 18. Kim ST, Jeong GE, Kim SY, et al. The effect of voice therapy in vocal polyp patients. J Korean Soc Speech Sci. 2009;1:43–49. 19. Wang CT, Huang TW, Liao LJ, et al. Office-based potassium titanyl phosphate laser-assisted endoscopic vocal polypectomy. JAMA Otolaryngol Head Neck Surg. 2013;139:610–616. 20. Wang CT, Liao LJ, Cheng PW, et al. Intralesional steroid injection for benign vocal fold disorders: a systematic review and meta-analysis. Laryngoscope. 2013;123:197–203.