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Background
The recurrent laryngeal nerves of the vagus nerves are the primary innervators of the abductors and adductors of the vocal folds. Isolated injury of the recurrent laryngeal nerve results in paralysis of the vocal cord in the para-median position on one side, 2 to 3 mm lateral to the laryngeal midline. Combined injury of the recurrent and superior laryngeal nerves paralyzes the vocal cord in the intermediate position, several millimeters lateral to the para-median position.
Vocal cord paralysis may be unilateral or bilateral, central or peripheral. Unilateral left vocal cord paralysis is most common. Less than 20 % of cases are bilateral. Thyroidectomy is by far the most common cause of bilateral vocal cord paralysis. Central causes include brain stem and supranuclear lesions and account for only 5 % of all cases. Supranuclear or cortical causes of vocal cord paralysis are exceedingly rare, owing to the bilateral crossed neural innervation to the brain stem medullary centers in the nucleus ambiguus. The most frequent central cause is vascular insufficiency or a stroke affecting the brain stem. Congenital central lesions are usually secondary to Arnold-Chiari malformation or brain stem dysgenesis and are often associated with additional cranial neuropathies.
Most cases of peripheral vocal cord paralysis are secondary to thyroidectomy or non-laryngeal neoplasms, including bronchogenic, esophageal, and thyroid carcinoma. Other less common lesions causing paralysis of the vocal cord include tumors of the deep lobe of the parotid gland, carotid body tumors, glomus jugulare and vagale tumors, and neurogenic neoplasms of the tenth nerve and jugular foramen. External penetrating wounds to the neck or prolonged endotracheal intubation may also traumatize the recurrent laryngeal nerve, producing vocal cord paralysis. Finally, toxic neuropathy and idiopathic causes account for a few cases.
In adults, unilateral recurrent laryngeal nerve paralysis generally produces hoarseness and a weak, breathy voice with varying amounts of aspiration. The normal vocal cord may cross the midline to approximate the paralyzed vocal cord in the para-median position. In children, varying degrees of inspiratory stridor may also be present. Bilateral vocal cord paralysis is commonly associated with inspiratory stridor, shortness of breath, and dyspnea on exertion.
Management of unilateral vocal cord paralysis due to lesions of the recurrent laryngeal nerve includes the injection of Teflon paste or Gelfoam under local anesthesia into the paralyzed vocal cord, mobilizing it medially. Medialization is valuable in the therapy of aspiration and results in dramatic improvement in voice quality. Other injection options for glottic insufficiency include bovine collagen, calcium hydroxylapatite, injectable fat, and Gelfoam. An assessment by the National Institute for Clinical Excellence (NICE, 2005) concluded that there are no major safety concerns regarding collagen injections for vocal cord augmentation and that they provide short-term symptom relief. However, evidence on long-term efficacy is lacking. Belafsky and Postma (2004) stated that initial experience with vocal fold augmentation using calcium hydroxylapatite is promising. However, its long-term safety and effectiveness needs to be established. Medialization of the paralyzed cord may also be accomplished externally via a thyroidotomy and placement of a Silastic wedge implant inside the thyroid cartilage in a small pocket deep to the paralyzed vocal cord.
The upper airway obstruction caused by bilateral vocal cord paralysis usually requires a tracheostomy initially. Subsequent improvement in the airway can be obtained with an arytenoidectomy.
Cymetra (micronized AlloDerm tissue) has been studied for soft tissue augmentation. In a preliminary report on voice quality as well as quality-of-life following Cymetra injection laryngoplasty in patients with unilateral vocal cord paralysis (n = 14), Pearl et al (2002) stated that Cymetra appears to be a safe new material that is suitable for injection laryngoplasty. Moreover, long-term results are pending.
In a study with 10 patients with breathy dysphonia caused by unilateral vocal fold paralysis, Karpenko and colleagues (2003) examined the effectiveness of transoral injection of Cymetra for this indication. Each patient underwent pre-operative and post-operative acoustic analysis, aerodynamic measures, taped voice sampling, and videostroboscopy. Significant improvements were identified in maximum phonation time, relative glottal area, and subjective judgment of glottal competency. However, these results were not maintained at the 3-month study interval. No significant change in quantitative or subjective voice quality was noted for the study group during the investigation. The investigators stated that resorption of Cymetra may play a significant role in contributing to these findings.
Rees and colleagues (2008) reviewed the clinical results of the thyrohyoid approach for in-office vocal fold augmentation with calcium hydroxylapatite (CaHA/Radiesse). The charts of all patients who underwent in-office thyrohyoid vocal fold augmentation between June 1, 2005 and June 1, 2007 were reviewed. Information with respect to patient demographics, indications, complications, and clinical outcome was abstracted. A total of 51 thyrohyoid vocal fold augmentations were performed in 33 patients (26 men; mean age of 66 years). Six (13 %) procedures were aborted as a result of an inability to achieve an appropriate injection angle. Two (6 %) self-limited complications included a vasovagal episode and a small ulcer near the petiole of the epiglottis. Pre- and post-procedure data were available for 62.5 %. The mean 10-item Voice Handicap Index (VHI) improved from 27.9 (+/- 8.40) pre-procedure to 13.5 (+/- 10.52) post-procedure (p < 0.001). The authors concluded that in-office vocal fold augmentation with the use of the thyrohyoid approach demonstrates excellent clinical results. It has become these investigators' technique of choice for vocal fold medialization with the patient under local anesthesia in the office setting. Complications are rare.
Rosen et al (2009) evaluated the long-term effectiveness of CaHA vocal fold injection for patients with glottal insufficiency. Each patient served as his/her own control. Voice-related outcome measures were collected for pre-injection, 1, 3, 6, and 12 months. A total of 63 patients were available for evaluation; 53 % of the injection procedures were done in the office and 57 % of patients were diagnosed with unilateral paralysis and 43 % with glottal incompetence with mobile vocal folds. Patient satisfaction 12 months after injection showed 67 % reporting a significant improvement in voice and 81 % reporting at least a moderate improvement in voice. Utilizing the VHI-10, visual analog scale (vocal effort), Consensus Assessment Perceptual Evaluation V (judgments of voice severity), and objective voice measures of glottal closure (maximum phonation time and S:Z ratio), paired-t tests showed significant improvements after treatment. A 22 % further treatment rate was found at the 12-month time point. The authors concluded that 1-year results in this large cohort of patients with glottal incompetence treated with CaHA vocal fold injection demonstrate that excellent clinical results were achieved.
In a multi-institutional retrospective review, Sulica et al (2010) identified contemporary indications, treatment principles, technique, injection materials, complications, and success rates of vocal fold injection augmentation. Records of patients undergoing injection augmentation at 7 university medical centers from July 2007 through June 2008 were reviewed for information regarding diagnosis, unilateral or bilateral injection, route of injection, anesthesia, treatment site (office or operating room), material used, reason for technique selected, and technical success. In 12 months, 460 injections were performed, 236 (51 %) in awake, unsedated patients, and 224 (49 %) under general anesthesia. Indications included vocal fold paralysis (248; 54 %), paresis (97; 21 %), atrophy (68; 15 %) and scar (47; 10 %). Scar was more likely to be treated in the operating room (p = 0.000052). In awake patients, 112 (47 %) injections were performed by transcricothyroid approach, 55 (23 %) by peroral approach, 49 (21 %) by trans-thyrohyoid membrane approach, and 20 (8 %) by trans-thyroid cartilage approach. Neither technical success rate (99 % versus 97 %) nor complication rate (3 % versus 2 %) differed between awake and asleep techniques. The most common materials in the clinic setting were methylcellulose (35 %), bovine collagen (28 %), and CaHA (26 %); in the operating room these were CaHA (36 %) and methylcellulose (35 %). Calcium hydroxylapatite was more likely to be used under general anesthesia (p = 0.019). Five-year data show that the use of injection in the awake patient rose from 11 % to 43 % from 2003 to 2008. The authors concluded that injection augmentation remains a safe, effective, and clinically practical treatment with a high rate of success, whether performed in the awake or asleep patient. The rapid adoption of awake injection over the past 5 years speaks to its clinical utility. Complication rates are low and equivalent to those under general anesthesia.
Medialization thyroplasty (MT), also known as type 1 thyroplasty, is one of the several surgical procedures that are employed for the treatment of unilateral vocal fold paralysis (UVFP). It entails the trans-cervical placement of an implant through a surgically created window in the thyroid cartilage to achieve medialization of the vocal fold so that better closure can be achieved.
Laccourreye and colleagues (2005) documented the long-term results achieved with the Montgomery implant in 96 patients with a unilateral laryngeal nerve paralysis (ULNP). Data regarding morbidity and functional results were obtained at regular visits to the clinic. All patients were followed for a minimum of 6 months or until death. A total of 42 patients had a minimum of 12 months of follow-up. Early in the study, 36 patients were prospectively recorded under similar conditions before placement of the Montgomery implant and at 1, 3, 6, and 12 months post-operatively. None of the 96 patients died in the immediate post-operative period. The peri-operative course was unremarkable in 94.8 % of cases. Peri-operative problems included failure to obtain a satisfactory phonatory result in 3 patients, difficulty to stabilize the implant posteriorly in 1 patient, and fracture of the inferior rim of the thyroid cartilage window in another patient. The primary immediate post-operative problem (within the first post-operative month) was laryngeal dyspnea, noted in 4 patients. According to the patient's subjective assessment, speech and voice was always improved in the immediate post-operative period. However, 3 patients had secondary degradation of speech and voice. Revision surgery under local anesthesia resulted in a 97.9 % ultimate speech and voice success rate. According to the patient's subjective assessment, adequate swallowing in the immediate post-operative period was achieved in 94.2 % of cases that had swallowing problems pre-operatively. A significant statistical increase in the duration parameters (phonation time, phrase grouping, speech rate) together with a statistical significant decrease in both the jitter and shimmer values was noted when comparing the pre-operative and the post-operative values at 1 month. Analysis of the evolution of the speech and voice parameters at 1, 3, 6, and 12 months post-operatively showed a significant decrease in the fundamental frequency and noise-to-harmonic ratio values but did not demonstrate any significant differences for the other speech and voice parameters. The authors concluded that type I thyroplasty with Montgomery implant insertion is a safe and reproducible method to treat ULNP. Furthermore, this system achieves very good and stable phonatory results. Finally, the use of this technique and implant system appears safe in patients from various cultures with ULNP from a variety of causes and severe comorbidity. Over the past decade at the authors' department, this procedure progressively replaced the use of the intra-cordal injection of autologous fat injection that was initially advocated in patients with ULNP.
Lam et al (2007) reported on the use of MT in patients (n = 87) with symptomatic cancer-related UVFP. There were no significant differences between the cancer-related and benign groups in terms of the speech and swallowing rehabilitation outcome and the peri-operative complication rate (p > 0.05). The median survival time of cancer-related UVFP patients from the date of medialization to death was 129 days. Age greater than 65 years was identified as the only factor for a shorter survival period after medialization (p = 0.040). The authors concluded that MT restores satisfactory speech and swallowing and has a low peri-operative complication rate in patients with cancer-related UVFP. Furthermore, post-medialization survival period was also reasonable.
In a prospective observational cohort study, Storck and associates (2007) assessed functional results of MT using a hydroxyapatite implant (VoCoM) for the treatment of UVFP. A total of 26 patients (19 men, 7 women) were enrolled in the study. To evaluate voice function, the following parameters were measured pre-operatively and post-operatively: mean fundamental frequency, mean sound pressure level, frequency and amplitude range (voice range profile), and maximum phonation time. A perceptual assessment of hoarseness was conducted using the Roughness, Breathiness, Hoarseness scale. Furthermore, the magnitude of voice related impairment of the patient's communication skills was rated on a 7-point scale. A combined parameter called the Voice Dysfunction Index (VDI) was used to rate vocal performance. All patients showed a statistically significant improvement in the VDI, in perceptual voice analysis, in maximum phonation time, and in the dynamic range of voice. One patient experienced a post-operative wound hemorrhage as a minor complication. No further complications or implant extrusions were observed. The authors concluded that MT using a hydroxyapatite implant is a secure and efficient phono-surgical procedure. Voice quality and patient satisfaction improve significantly after treatment.
Chrobok et al (2008) implemented MT with a customized silicone implant in a total of 43 operations (36 patients). In 5 of these patients, the MT was combined with cricothyroid subluxation (3 cases) or adduction of arytenoid cartilage (3 cases). One patient received MT, cricothyroid subluxation and adduction of arytenoid cartilage. Post-operatively, 36 patients reported substantial reduction of their complaints, 5 patients found their voice improved and only 2 patients (5.6 %) stated that their voice had not changed. The subjective evaluation was consistent with the findings of laryngoscopy and the pre-operative and post-operative phonation parameters (maximum phonation time, maximum sound pressure level, jitter and shimmer). Average maximum phonation time was 6.5 seconds before surgery and 12.5 seconds after surgery. Maximum vocal sound pressure level was, on average, about 4 dB higher after surgery. Jitter was reduced from 5.3 % to 3.7 % and shimmer from 32.3 % to 18.6 %. The differences between pre-surgical and post-surgical parameters in this study were all statistically significant, indicating voice improvement. The authors concluded that MT with a silicone implant was proven to be a successful and safe surgical method for the treatment of vocal fold paralysis.
Dursun and co-workers (2008) examined the early and long-term functional results of type I thyroplasty and injection laryngoplasty using fat or calcium hydroxylapatite. A total of 30 patients with glottic insufficiency were included and followed-up between 1 to 7 years. Patients with glottic bowing or sulcus vocalis were selected for injection augmentation of the vocal folds, while those with UVFP underwent MT. Perceptual and acoustic analysis of voice, and videolaryngostroboscopy were performed before and after surgery. After the surgery, GRBAS (grade, rough, breathy, asthenic, strained) scale (where 0 = normal, 1 = mild, 2 = moderate and 3 = severe) of all patients demonstrated significant change in grade of severity, roughness, and breathiness. Acoustic analysis showed significant change in fundamental frequency (Fo), jitter, shimmer, noise to harmonic ratio, and maximum phonation time (MPT) in thyroplasty group, while those demonstrated significant change in Fo (lowest) and jitter, and MPT in injection augmentation group. The authors concluded that MT is the gold standard for the management of glottic insufficiency, regardless of the severity of glottic gap. However, injection augmentation of the vocal folds may be considered as an alternative in the treatment of patients with small glottic gap.
Broniatowski and colleagues (2010) examined if respiratory compromise from bilateral vocal fold impairment (paralysis) can be objectively alleviated by re-innervation and pacing. A patient with paramedian vocal folds and synkinesis had a tracheotomy for stridor after bilateral laryngeal nerve injury and Miller Fisher syndrome. One posterior cricoarytenoideus (PCA) received a nerve-muscle pedicle fitted with a perineural electrode for pacemaker stimulation. The airway was evaluated endoscopically and by spirometry for up to 1 year. Bilateral vocal fold patency during quiet breathing was reversed to active vocal fold adduction during tracheal occlusion. Peak inspiratory flows were significantly higher (p < 0.001) after re-innervation. Peak inspiratory flows as well as glottic apertures increased further under stimulation (42 Hz, 1 to 4 mA, 42 to 400 microsec); although the differences were insignificant. The authors concluded that based on these preliminary data, PCA re-innervation and pacing offer promise for amelioration of respiratory compromise after paradoxical adduction in bilateral vocal fold paralysis.
Fang et al (2010) analyzed outcomes following fat injection laryngoplasty in patients with unilateral vocal cord paralysis. A total of 33 consecutive patients with unilateral vocal cord paralysis undergoing autologous fat injection laryngoplasty with pre-operative and serial post-operative follow-up were included in this analysis. Main outcome measures were voice laboratory measurements, Voice Outcome Survey, and 36-item Short Form Health Survey. Except for the physical functioning dimension of global health, voice-related subjective outcomes and acoustic variables of the patients significantly improved after surgery (p < 0.05). Compared with population norms, the mean (SD) scores of patients were inferior on the 36-item Short Form Health Survey dimensions of physical functioning (80.7 [22.3] versus 90.2 [17.4]) and role functioning-physical problems (65.0 [36.2] versus 80.2 [36.2]). Overall, 88.9 % (24 of 27) of the patients were satisfied with their surgery. The authors concluded that fat injection laryngoplasty seems to be effective in enhancing acoustic and quality of life outcomes in patients with unilateral vocal cord paralysis. The effect is sustainable over 12 months.
Zhang et al (2011) evaluated the effect of combination of autologous fascia and fat injection into vocal fold for the treatment of patients with unilateral vocal fold paralysis and observed the long-term effectiveness of this procedure. A total of 26 unilateral vocal fold paralysis patients underwent vocal fold injection under general anesthesia, meanwhile, the mucosa of the injected point was sutured through laryngoscope under direct vision. There were 6 patients underwent autologous fat injection into vocal fold (group A), and 20 patients underwent autologous anterior rectus sheath fascia and fat injection (group B). Therapeutic efficacy were evaluated by videostroboscopy, voice-related parameters analysis and voice evaluation before and after treatment. Clinical analysis of this procedure was retrospectively performed in this serial of patients. All patients were followed-up for 24 months. On the third day after operation, there was an acute inflammatory reaction induced by the graft. This reaction disappeared 3 months later. In all 20 cases, videolaryngostroboscopy showed significant improvement of the glottic closure, the improvement in acoustical parameters was statistically significant (p < 0.01). Perceptual evaluation of GRBAS scale showed significant improvement of phonatory function on G, B, A scale. The results remained stable 6 to 24 months after operation and were not changed by the length of follow-up. And in the 6 cases, videolaryngostroboscopy showed significant improvement of the glottic closure at 3 months compared with pre-operative observation, a little spindle-shaped disclosure. The improvement in acoustical parameters was significant statistically at 3, 6 and 24 months (p < 0.05 or < 0.01), the voice quality decreased significantly at 6 and 24 months compared with 3 months (p < 0.05 or < 0.01). The significant differences were not observed between 6 and 24 months (p > 0.05). No complications were observed in all patients peri-operatively or during the follow-up period. Voice-related parameters jitter, normalized noise energy and maximum phonation time showed significant differences between Group A and Group B on 24 months (p < 0.05 or < 0.01). The authors concluded that the combination of autologous fascia and fat vocal fold injection is an effective procedure for the treatment of unilateral vocal fold paralysis, and the stable results can be achieved during the follow-up period for 24 months.
Mazzola et al (2011) stated that minimally-invasive autologous fat injection of the head and neck region can be considered a valid alternative to major invasive surgical procedures both for aesthetic and functional purposes. The favorable outcomes of autologous fat injection in otolaryngological practice are due to the filling of soft tissue and, mainly, to the potential regenerative effect of adipose-derived mesenchymal stem cells. Herewith, some important biological preliminary remarks were described underlying the potential of autologous fat injection in regenerative medicine, and personal experience in using it for both consolidated clinical applications, such as fat grafting to the face and vocal fold augmentation in the treatment of glottic incompetence, and more recent applications including the treatment of post-parotidectomy Frey syndrome and velopharyngeal insufficiency. The authors noted that vocal fold augmentation by means of autologous fat injections for glottic incompetence has been standardized and used in their clinic for several years.
Radiesse, originally approved as a wrinkle filler, received additional clearance from the Food and Drug Administration for the treatment of vocal cord insufficiency (2007). Radiesse is injected lateral to the vocal folds and the vocalis muscle. The bulking effect of the implant medializes the vocal folds, facilitating speech and preventing inadvertent aspiration of liquids, as well as correcting shortness of breath caused by laryngeal incompetence. The Radiesse injection procedure can be performed percutaneously or trans-orally with endoscopic guidance, with local or topical anesthetic as required. Since the procedure can be performed in-office with the patient awake and able to talk, patients' speech can be evaluated immediately and the amount of material needed for optimal correction can be more accurately determined.
Carroll et al (2011) reported the long-term effectiveness of CaHA/Radiesse as a vocal fold injectable by assessing data from a cohort of patients who underwent injection for glottal insufficiency. Patients who underwent CaHA injection for glottal insufficiency of any etiology were considered for inclusion in the study. The change in VHI-10 scores between pre-injection scores and best post-injection scores as well as between the pre-injection and the most recent VHI-10 scores were used as primary outcome measures to determine the persistence of benefit or the time to loss of benefit. Complications among the cohort were identified. A total of 90 patients who underwent 108 vocal fold injections with CaHA were evaluated for inclusion. Twenty patients with 22 injections met the criteria for inclusion. Fourteen of 22 (64 %) subjects showed loss of benefit of the CaHA material. The average length of benefit was 18.6 months, with a range of 8 to 36 months. Three complications were identified among the original cohort of 108 injections. The authors concluded that CaHA remains a safe and effective long-term vocal fold injectable with an average length of benefit of 18.6 months. Three complications were seen among 108 CaHA injections. They stated tht CaHA is a long-term injectable with an excellent track record that does not appear to warrant concern for permanent or late complications.
Yung and colleagues (2011) examined if temporary vocal fold injection affects the need for permanent medialization laryngoplasty in patients with UVFP. A total of 175 patients with dysphonia resulting from UVFP were identified. Patients with documented recovery of vocal fold mobility, less than 9 months of follow-up after diagnosis of UVFP, previous treatment at other institutions, neoplastic disease involving the larynx, or history of radiation to the larynx were excluded. A total of 54 patients met all inclusion/exclusion criteria. Rates of permanent medialization laryngoplasty in patients undergoing vocal fold injection were compared with those of patients who chose observation or voice therapy. A total of 35 % of patients underwent temporary injection medialization, and the remaining 65 % chose conservative management. Five of 19 of the temporary injection medialization patients subsequently underwent permanent intervention compared to 23 of 35 of the conservative management group (p = 0.0131). The authors concluded that UVFP patients who underwent vocal fold injection with an agent intended to provide temporary medialization were statistically significantly less likely to undergo permanent medialization laryngoplasty compared to those patients who were treated with conservative management only.
Song et al (2010) noted that a variety of materials as well as approaches have been used to treat glottic insufficiency, but the ideal procedure has yet to be determined. The goal of this study was evaluate the safety and effectiveness of cross-linked hyaluronic acid (HA; Restylane) for office-based injection laryngoplasty for the treatment of vocal fold (VF) immobility. These researchers performed a retrospective chart review of 27 patients with VF immobility; 25 received Restylane VF injections in the office setting via percutaneous, trans-thyrohyoid injection with distal chip endoscopic guidance. Two patients received injections using suspension microlaryngoscopy under general anesthesia. Voice outcomes were followed using the Voice-Related Quality of Life Survey and the Voice Outcome Survey. Four patients were lost to follow-up immediately after injection; 20 of 23 patients (87 %) reported subjective improvement in voice. Analysis of subjective surveys from 9 patients revealed a trend toward improvement of V-RQOL from 34 to 23 (p = 0.083); but did not reach significance. After compilation of all VOS questions, 69 % of all follow-up responses noted improvement of symptoms, 24 % were unchanged and 7 % were worse. The authors concluded that office-based injection laryngoplasty with Restylane appears to be a safe procedure that improves vocal function in patients with glottal insufficiency due to impaired VF mobility. Moreover, they stated that further studies are needed to quantify the benefits and to compare the effects with other injectable materials.
In a prospective study, Wang et al (2012) examined the feasibility of using an injectable needle electrode to guide VF injection (VFI) of HA during laryngeal electromyography (LEMG) for unilateral VF paralysis (UVFP). From March to June 2010, a total of 20 UVFP patients received LEMG examination. Before completion of LEMG, 1.0 cc of HA (Restylane Perlane(®); Q-Med, Uppsala, Sweden) was injected via a 26-gauge monopolar injectable needle electrode into paralyzed thyroarytenoid muscle. After injection, 20 patients completed 3-month follow-up and 16 patients completed 6-month follow-up. The data before, 1 week, 3 months, and 6 months after injection, including the normalized glottal gap area (NGGA) from videostroboscopy, maximal phonation time (MPT), mean airflow rate (MAFR), phonation quotient (PQ), perceptual evaluation of voice (grade, roughness, breathiness, asthenia, strain [GRBAS] scale), Voice Handicap Index (VHI), and self-grading of choking (grade 1 to 7), were analyzed by the Wilcoxon signed rank test. All of the patients completed the procedure without complications. After injection, mean NGGA was significantly reduced from 8.28 units to 0.52 units (1 week), 1.79 units (3 months), and 1.36 units (6 months). The mean MPT was prolonged from 5.66 seconds to 11.73, 11.25, and 11.93 seconds, respectively. Voice Handicap Index HI was reduced from 76.05 to 38.10, 37.40 and 35.00, respectively. Other analyzed data (PQ, MAFR, GRBAS scale, and choking severity) also showed statistically significant improvement. The authors concluded that LEMG-guided HA VFI provides UVFP patients with neuromuscular function evaluation and treatment in one step. This clinical technique is feasible, and the short-term results are satisfactory. These preliminary findings need to be validated by well-designed studies with more patients and longer follow-up.
In a Cochrane review, Lakhani et al (2012) evaluated the effectiveness of alternative injection materials in the treatment of UVFP. These investigators searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was March 23, 2012. Randomized controlled trials (RCTs) of injectable materials in patients with UVFP were selected for analysis. The outcomes of interest were patient and clinician-reported improvement, and adverse events. Two authors independently selected studies from the search results and extracted data. They used the Cochrane 'Risk of bias' tool to assess study quality. These researchers identified no RCTs that met the inclusion criteria for this review. They excluded 18 studies on methodological grounds: 16 non-randomized studies; 1 RCT due to inadequate randomization and inclusion of non-UVFP patients; and 1 RCT that compared 2 different particle sizes of the same injectable material. The authors concluded that there is currently insufficient high-quality evidence for, or against, specific injectable materials for patients with UVFP. They stated that future RCTs should aim to provide a direct comparison of the alternative materials currently available for injection medialization.
A Food and Drug Administration’s MAUDE Adverse Event Report on “Q-MED AB. Restylane injectable gelinjectable dermal filler” (FDA, 2007; last updated 1/31/2013) noted that vocal cord paralysis is not an approved indication for Restylane use.
The consensus report on “Vocal fold scars” by the Phonosurgery Committee of the European Laryngological Society (Friedrich et al, 2013) stated that scarring of the vocal folds leads to a deterioration of the highly complex micro-structure with consecutively impaired vibratory pattern and glottic insufficiency. The resulting dysphonia is predominantly characterized by a reduced vocal capacity. Despite the considerable progress in understanding of the underlying pathophysiology, the treatment of scarred vocal folds is still an unresolved chapter in laryngology and phonosurgery. Essential for a successful treatment is an individual, multi-dimensional concept that comprises the whole armamentarium of surgical and non-surgical (e.g., voice therapy) modalities. An ideal approach would be to soften the scar, because the reduced pliability and consequently the increased vibratory rigidity impede the easiness of vibration. The chosen phonosurgical method is determined by the main clinical feature: Medialization techniques for the treatment of glottic gap, or epithelium freeing techniques for improvement of vibration characteristics often combined with injection augmentation or implantation. In severe cases, buccal mucosa grafting can be an option. New developments, include treatment with anxiolytic lasers (e.g., pulse dye laser [PDL]; potassium titanyl phosphate [KTP] laser), laser technology with ultrafine excision/ablation properties avoiding coagulation (Picosecond infrared laser, PIRL), or techniques of tissue engineering. However, the authors concluded that despite the promising results by in-vitro experiments, animal studies and first clinical trials, the step into clinical routine application has yet to be taken.
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