|Year : 2011 | Volume
| Issue : 2 | Page : 55-59
Autologous fat augmentation for phonatory gap: Prospective study of postoperative voice outcome
Sachin Gandhi, Namita Narhari, Vrushali Desai
Department of Laryngology, Deenanath Mangeshkar Hospital, Pune, Maharashtra, India
|Date of Web Publication||19-Sep-2011|
Department of Laryngology, Deenanath Mangeshkar Hospital, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Substances available for vocal cord augmentation procedure have their own advantages and limitations. Autologous fat is accepted to be one of the safest substance for augmentation. Objective: To evaluate the subjective and objective changes in vocal outcome following fat augmentation surgery for phonatory gaps. Materials and Methods: 30 patients with phonatory gap <2 mm were included in this prospective study. These consisted of sulcus vocalis (14), vocal cord atrophy (05) and vocal cord palsy (11). Per-operatively harvested umbilical fat was used for augmentation after mincing it and removing all the connective tissue. Follow-up of patients was done at 1, 3 and 6 months interval. Pre- and postoperative videostroboscopy was done. Objective analysis of voice was done using maximum phonatory time (MPT) and noise to harmonic ratio (NHR). Subjective assessment of voice was done using the voice handicap index (VHI) and subjective change in quality of voice as assessed by the patient. Results: Patients with early stage sulcus, vocal atrophy and vocal cord palsy, with small vocal gap, showed significantly good results after fat augmentation; however, results of patients with sulcus vocalis of grade II and III were not very satisfactory.
Keywords: Fat augmentation, phonatory gap, videostroboscopy, vocal outcome
|How to cite this article:|
Gandhi S, Narhari N, Desai V. Autologous fat augmentation for phonatory gap: Prospective study of postoperative voice outcome. J Laryngol Voice 2011;1:55-9
| Introduction|| |
Vocal folds are primary responsible for phonation that varies in frequency, intensity and quality. Glottic incompetence due to vocal fold palsy or atrophy causes hoarse voice that is easily fatiguable as the patient attempts to overcome glottic insufficiency by increasing transglottic flow.  Incomplete glottic closure can result in dysphonia, ineffective cough and occasionally aspiration. Glottic incompetence is most commonly seen in patients with sulcus vocalis, unilateral vocal cord paralysis and vocal cord atrophy.  Many surgical techniques have been described to improve glottic competence, after sufficient trials of voice therapy have failed. The techniques more commonly performed are injection laryngoplasty, laryngeal framework surgery and laryngeal reinnervation.  Open neck medialization or laryngeal framework surgeries are invasive procedures with their own definitive risks of implant dislodgement, laryngocutaneous fistula and airway obstruction.  Reinnervation procedure, popularized by Crumley, helps to regain the muscle bulk and restore the tension of vocal ligament.  However, this is a technically challenging procedure with delayed results. 
Vocal cord augmentation is a relatively simple and short procedure. Various substances are available for this procedure, for example, fat, teflon, collagen, etc. and each has its own advantages and limitations.
Autologous fat has viscoelastic properties close to lamina propria  and provides good medialization and bulk to the vocal cord. It is soft and usually well tolerated in the larynx with minimum inflammatory reaction  and without any risk of hypersensitivity.  Fat is now accepted to be one of the safest physiological substance for augmentation. 
In the present study, fat augmentation was done to correct the phonatory gap and the vocal outcome of such patients was evaluated. Subjective and objective parameters were used in this study for evaluation.
| Materials and Methods|| |
This prospective study was undertaken from February 2008 to August 2009 at the Deenanath Mangeshkar Hospital, a tertiary care laryngology center in Pune in Western India. Institutional ethical committee approval was obtained for the study.
The cases included were of sulcus vocalis, unilateral vocal cord palsy and vocal atrophy, with a phonatory gap of
<2 mm and who failed the voice therapy of 6 months duration. Patients who underwent previous medialization surgery or had phonatory gap more than 2 mm were excluded from the study. Thirty patients met the inclusion criteria.
A detailed history was taken in terms of onset, duration, progress, vocal abuse and vocal fatigue. Associated symptoms suggestive of dysphagia, dyspnea, reflux disease and aspiration were noted. All patients underwent thorough general and systemic evaluation to rule out any co-morbidity. The findings were documented at study enrollment.
The diagnosis was confirmed with digital videolaryngostroboscopy (Kay Pentax RLS 9100B). The details of mobility of vocal fold, vocal cord edge and the phonatory gap were recorded. A voice analysis of these patients was done using MDVP software (Kay Pentax). Voice analysis included measurement of maximum phonation time (MPT) and that of noise to harmonic ratio (NHR). For MPT, the subjects were asked to maximally sustain the vowel /e/ after taking a deep breath and the MPT was recorded in seconds. This was done three times and the longest of the three readings was noted for documentation. For NHR, the MDVP software was used.
Patient's subjective assessment of his/her own voice and its effect on his/her quality of life was done using the voice handicap index (VHI) questionnaire. The questionnaire consisted of 30 questions. The patient had to self-grade the effect on quality of his/her life due to the change in voice by giving a score from 0 to 4. Final score would vary from 120 to 0, where 120 represents maximal effect due to vocal pathology.
Patients were followed for 1, 3 and 6 months after fat augmentation. Follow-up examination included videolaryngostroboscopy for structural changes. MPT and NHR were estimated for objective improvement. Subjective improvement was assessed by VHI and patient's self-assessment in quality of voice in terms of vocal fatigue, loudness of voice and quality of voice. The quality was graded as good, fair, no improvement or worse.
The surgery was performed under general anesthesia with endotracheal intubation. The endotracheal tube used was one size smaller than that used for conventional surgeries to allow better exposure. An anterior commissure micro-laryngoscope with operating microscope (Karl-Zeiss 400 mm lens) was used.
Fat was harvested from periumbilical subcutaneous tissue with a 2-cm incision in infraumbilical area. In cases with inadequate fat in periumbilical area, it was harvested from the gluteal region. Fat was harvested in several pieces and was minced by cutting with the help of a pair of scissors and mortar and pestle. It was ensured that all the connective tissue had been removed from the harvested fat. This fat was loaded retrograde into Brunings Syringe attached to an 18-gauge needle, and 0.75-1.5 ml was injected into the vocal cord. The site of fat augmentation was on the lateral aspect of the vocal cord just anterior to the vocal process to ensure even spread all along the vocal cord in a single puncture. Fat was overinjected to achieve 30% bulge across the midline. The injection site was sealed with diode laser to minimize leakage of fat [Figure 1],[Figure 2][Figure 3].
In patients who had developed ventricular phonation as a compensatory mechanism for phonatory gap, one of the false cords was excised. This was done to reduce the ventricular dysphonia.
Preoperative and postoperative comparison was done with paired "t" test. The analysis was performed using statistical software Minitab 15 and P value <0.05 was considered as statistically significant.
| Results|| |
The study group clinically consisted of patients with sulcus vocalis (n = 14), unilateral vocal cord paralysis (n = 11) and vocal cord atrophy (n = 5) [Table 1].
Twenty patients were males and 10 were females and the age group was from 30 to 50 years with a mean age of 39 years.
29/30 (96.6%) of patients had complete glottic closure at the end of 1 month. The patient who failed to show improvement in glottic closure was of grade III sulcus vocalis.
At the end of 3 months 23/30 (76.6%) patients and at the end of 6 months 21/30 (70%) patients had complete glottic closure. On inclusion of only cases of vocal cord palsy and vocal atrophy, 13 of 16 patients had good improvement (82%).
Majority of the patients showing consistent glottic closure were of unilateral vocal cord palsy and vocal cord atrophy. Patients who failed to show persistent glottic closure were of grade II and III sulcus vocalis. The detailed change in phonatory gap at 1, 3 and 6 months is as per [Table 2].
|Table 2: Postoperative change in phonatory gap at 1 month 3 month and 6 month interval|
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Maximum phonatory time
At the end of 6 months, MPT improved in almost all the cases. The increase in MPT was similar in all the three pathologies present in the study group [Table 3].
Noise to harmonic ratio
Significant improvement in the values of NHR was seen at the end of 6 months in all the three clinical groups. Average preoperative value of NHR was 0.21 in 20 male subjects. This improved to 0.130 at the end of 6 months (normative value 0.122). In 10 female patients, the average value of NHR improved to 0.115 from 0.156 (normative value 0.112) [Table 4].
Subjective evaluation on follow-up
Voice handicap index
VHI improved postoperatively in 27 of 30 patients. Average preoperative VHI was 40 of a maximum possible 120. The improvement was more (102) during immediate follow-up of 1 month, but lowered to 88 at 6 months follow-up. Patients with grade III sulcus continued to have lower VHI postoperatively.
Individual subjective improvement
23/30 (76.6%) cases showed subjective improvement and were satisfied with the quality of voice at the end of 6 months [Table 5].
There was significant correlation between subjective and objective improvement at the end of 6 months.
In seven patients, false cord excision was done as they had its hypertrophy due to ventricular phonation. All these seven patients had good voice postoperatively and did not require any voice therapy.
| Discussion|| |
It is well known that change in voice due to glottic insufficiency significantly affects patient's day-to-day communication, giving him/her social impairment. It is essential to have subjective analysis along with objective acoustic analysis in reporting outcomes of surgical procedure to correct glottic insufficiency.  Various treatment regimes have been described to treat this condition, with almost similar surgical results. 
Many etiological factors are known to produce phonatory incompetence, though vocal cord palsy, sulcus vocalis and vocal cord atrophy are the most common ones. Our study group consisted of patients with these most common etiological factors for phonatory gap.
The causes of hoarse voice leading to glottic insufficiency in the 30 patients studied at this tertiary care set-up comprised 14 cases of sulcus vocalis, 11 of unilateral vocal cord palsy and 5 of vocal cord atrophy. Hsiung et al., in their study on 33 patients, had similar configurations with 11 vocal cord atrophy patients, 13 vocal cord scarring patients and 9 unilateral vocal cord palsy patients. 
The technique using autologous fat for intracordal augmentation was first reported by Mikaelian  in 1991 and has been used clinically in various centers. Mikaelin et al., in their small series of three patients, had one patient with excellent postoperative voice and the other two had improved glottic closure and increase in MPT. Good results with the use of autologous fat augmentation have been achieved by many other investigators since then. ,
In our series of 30 patients, 23 had good glottic closure at the end of 6 months as evaluated by videostroboscopy. The failed cases were mostly of grade III sulcus vocalis. This failure in sulcus vocalis cases could be a result of loss of lamina propria, impairing the mucosal waves. For such condition, tissue regeneration has been attempted at our center using atelocollagen; however, it is at a pilot stage for the results to be compared. 
Improvement in MPT was seen in all cases of vocal cord atrophy, most cases of vocal cord palsy and few cases of sulcus vocalis. This was probably related to the fact that patients with vocal cord atrophy as well as vocal cord palsy had a pliable vocal fold layer due to intact lamina propria.
Brandenburg et al. treated 12 patients, 11 patients for vocal fold paralysis and 1 for scarred vocal fold. VHI and Grade, Roughness, Breathiness, Asthenia, Strain (GRBAS) scale before and after surgery showed 80% improvement.  Morgan et al., in their study on 19 patients concluded perceptual and subjective analysis at an average follow-up of 3 months and this is comparable to medialization procedure.  Oluwole et al., in their study on 14 patients, with short-term follow-up found good vocal improvement. 
Hsiung et al., in their study with an average follow-up of 9 months on use of autologous fat for vocal insufficiency in 33 patients concluded that fat is a good material implant when the vocal fold defects are less.  Shaw et al., in their series of 22 patients, had 11 patients of paralysis and the rest with volume deficiency. In their study, there was objective and subjective improvement observed in all 22 patients after a follow-up of 12 months.  The findings and results of our study correlate well with the above studies.
Winson et al. compared the injection technique and thyroplasty in their study on 34 patients, and over a 6-month follow-up, they concluded that both have efficacy in achieving voice improvement.  We obtained good results with fat augmentation in our study, but comparison with any other technique has not been done.
Fat is an autologus graft which gets absorbed, making the duration of glottic closure unpredictable. Various studies have reported the absorption rates between 6 months and 2.5 years.  In spite of this, our results and those reported in other such studies are encouraging. The longstanding good vocal outcome would not necessarily mean nonabsorption of fat, but it could also be due to good compensation over time or recovery of vocal cord parlaysis. To correlate good vocal outcome and fat augmentation, we need to do serial imaging studies to check the presence of fat.
Patients with longstanding phonatory gap devlop ventricular phonation as a compensatory mechanism. These patients need additional voice therapy after surgery. We excised the hypertophied ventricular band on one side during surgery and obtained good results without the need of voice therapy.
| Conclusion|| |
Our study on 30 patients shows that fat is a safe, well tolerated, economical and effective tool for vocal cord medialization.
Patients with early stage sulcus, vocal atrophy and vocal cord palsy, who had small vocal gap, showed better results after fat augmentation; however, results of patients with sulcus vocalis of grade II and III were not satisfactory.
Based on the encouraging results of present study in terms of objective and subjective outcome, it can be stated that autologous fat is an excellent tool for medialization or augmentation of vocal cord.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]