An Integrated Experimental-Computational Study of Vocal Fold Vibration in Type I Thyroplasty.

Subject-specific computational modeling of vocal fold (VF) vibration was integrated with an ex vivo animal experiment of type 1 thyroplasty to study the effect of the implant on the vocal fold vibration. In the experiment, a rabbit larynx was used to simulate type 1 thyroplasty, where one side of the vocal fold was medialized with a trans-muscular suture while the other side was medialized with a silastic implant. Vocal fold vibration was then achieved by flowing air through the larynx and was filmed with a high-speed camera. The three-dimensional computational model was built upon the pre-operative scan of the laryngeal anatomy. This subject-specific model was used to simulate the vocal fold medialization and then the fluid-structure interaction (FSI) of the vocal fold. Model validation was done by comparing the vocal fold displacement with postoperative scan (for medialization), and by comparing the vibratory characteristics with the high-speed images (for vibration). These comparisons showed the computational model successfully captured the effect of the implant and thus has the potential for presurgical planning.

Modified Montgomery thyroplasty: Customisation of the cartilage window according to laryngeal anatomy.

We described a Montgomery's thyroplasty using a set of measurement devices designed to achieve accurate individualised prosthesis placement. The objective of the present study was to describe the surgical techniques employed via a step-by-step video and show our results. In total, 42 modified thyroplasties were performed during the 10-year study period. The verification of both points: adequate location and size of the prosthesis are the keys to the success of this intervention. The individualisation of the cartilage window location produces optimal functional results in patients post-intervention in terms of the MPT, GRB score, and VHI-30.

Long-term voice outcomes of medialization thyroplasty with adjustable implant for unilateral vocal fold paralysis.

OBJECTIVES: Medialization thyroplasty (MT) using various implants has been employed as a corrective procedure for unilateral vocal fold paralysis (UVFP). A newly developed APrevent® vocal implant system (VOIS) offers an innovative solution with a finely adjustable design. This study aimed to investigate the long-term functional voice outcomes and benefits of postoperative adjustments in patients receiving MT using the VOIS-implant. METHODS: This is a prospective case series study at single tertiary medical center. Fourteen adult patients diagnosed with UVFP received MT with the VOIS implant and were followed up for more than 1 year. Implant adjustment procedure by injecting 0.9% physiological saline solution was performed both during and after the surgery to optimize glottal closure and voice quality. Objective voice outcomes and acoustic parameters were assessed preoperatively and postoperatively at various timepoints. RESULTS: Thirteen patients (93%) received intraoperative balloon adjustment, ranging from 0.05to 0.12 ml. Four patients underwent adjustments postoperatively and exhibited a positive trend towards immediately improving acoustic voice quality. Our long-term results demonstrated a notable improvement after the surgery in voice quality, with significant decreases in VHI-30 and improvements in perceptual parameters of GRBAS scale, acoustic measures such as jitter and signal-to-noise ratio (p < 0.001) and cepstral peak prominence smoothed in sustained vowel and short sentences. The voice outcomes remained stable more than 1 year follow-up. CONCLUSIONS: Overall, MT with VOIS implantation provides a favorable long-term outcomes and stability in voice quality for patients with UVFP and also an effective tool for postoperative adjustment without major revision surgeries.

Voice outcome in medialisation thyroplasty with and without arytenoid adduction: a prospective comparison using intraoperative voice measurements.

PURPOSE: Arytenoid adduction as an addition to medialisation thyroplasty is highly advocated by some surgeons in selected cases but deemed less necessary by others in patients with unilateral vocal fold paralysis. This study aims to evaluate the additional benefits on voice outcome of arytenoid adduction in patients with unilateral vocal fold paralysis undergoing medialisation thyroplasty using intra-operative voice measurements. DESIGN/METHODS: A prospective study was conducted. Voice audio recordings were obtained at 4 moments; 1. direct prior to the start of surgery, 2. during surgery after medialisation thyroplasty, 3. during surgery after medialisation and arytenoid adduction, 3 months postoperative. At these same timepoints patients rated their own voice on a numeric rating scale between 0 and 10. The blinded recordings were rated by consensus in a team of experienced listeners, using the Grade of the GRBAS scale. Furthermore, the Voice Handicap Index was administered before and at 3 months after surgery. RESULTS: Ten patients who underwent medialisation and arytenoid adduction at our tertiary referral hospital between 2021 and 2022, were included. One patient was excluded after surgery. The intraoperative measurements showed a Grade score of 1.4 preoperatively, improving to 1.2 after medialisation, 1.2 after medialisation and arytenoid adduction, and further improving to 0.4 at 3 months postoperative, which was a not statistically significant improvement (p = 0.2). The intraoperative subjective numeric rating scale showed a statistically significant improvement from 3.9 preoperatively, to 6.1 after medialisation, 7.1 after medialisation and arytenoid adduction and a 7.6 at 3 months postoperative (p = 0.001). The Voice Handicap Index total score showed a statistically significant improvement from 71 points before surgery to 13 at 3 months after surgery (p = 0.008). CONCLUSIONS: Our study using intraoperative voice measurements indicate that the addition of arytenoid adduction to medialisation thyroplasty is a benefit in selected patients although more studies are needed due to the many limitations inherent to this field of investigation.

Management of Implant Extrusion following Thyroplasty for Vocal Fold Paralysis: A Case Report.

The most widely used laryngeal surgery technique for patients with vocal fold paralysis is medialization thyroplasty. Materials such as Gore-Tex, silastic, and hydroxyapatite are often used, and the most worrisome possible complication is extrusion of the implant. A 36-year-old female patient with a history of pediatric cardiac surgery was diagnosed with left vocal cord paralysis after an episode of upper respiratory infection with a working diagnosis of subclinical left vocal cord paralysis following cardiac surgery. She underwent medialization thyroplasty with a Gore-Tex implant under local anesthesia. On the 21st postoperative day, she presented with sudden-onset hoarseness and dysphagia due to Gore-Tex implant extrusion. The implant was removed and augmentation of the left vocal cord with adipose tissue was performed. Only 14 cases of Gore-Tex implant extrusion have been described in the literature so far. The aim of this case report was not only to show one possible complication when using a Gore-Tex implant but also to present fat augmentation as one of the solutions for revision medialization and salvage treatment, with sustained long-term results.

A systematic review and meta-analysis on the outcomes of type I thyroplasty in the irradiated neck.

BACKGROUND: Type I thyroplasty has been well-documented as a safe and effective treatment modality for vocal fold motion impairment, as well as other select cases of persistent glottic insufficiency. However, history of prior radiation to the neck has traditionally been viewed as a relative, if not formal contra-indication to this procedure. The objective of this systematic review was to analyze all available data in the literature on type I thyroplasty in previously irradiated patients and perform a meta-analysis assessing whether complications and revision rates are significantly different between radiated and non-irradiated patients. Secondary outcomes were to compare voice outcomes between these cohorts. METHODS: Several databases were screened for relevant citations using the PICO process. The quality of studies and risk of bias were evaluated using the MINORS scoring system. Main endpoints for analysis in this study were complication rate and revision rate. Secondary endpoint was reported voice outcome. RESULTS: Three articles were included in the analysis. Zero major complications were reported, including no instances of implant extrusion or explantation. There was an 11.8 % rate of minor complications. There were similar rates of revision between radiation and control groups. There was no significant difference in voice outcomes between groups. The average MINORS score of the studies suggested a high risk of bias. CONCLUSIONS: Based on limited quality evidence, this review suggests that type I thyroplasty is safe and feasible in carefully selected irradiated patients, with comparable complication and success rates as their non-irradiated cohorts. Further large-scale studies are warranted.

Custom Laser-Cut Silastic® Implants for Type I Thyroplasty in a Preclinical Model.

This study aimed to produce customized silicone elastomer implants of varied size and shape for optimization of type I thyroplasty procedures in a rabbit model. Computer-aided design models of different implant designs were designed and used to program laser cutting of a medical-grade Silastic® sheet. Laser-cut implants were produced rapidly and cost-efficiently. Surgical implantation demonstrated vocal fold medialization and phonation in 5 test subjects. This technique may provide a low-cost alternative or adjunct method to hand-carving or commercial implants.

An Analysis of Postoperative Complications in Medialization Thyroplasty: NSQIP Data.

INTRODUCTION: Medialization thyroplasty is a procedure indicated for treatment of impaired vocal fold movement. The purpose of this study was to identify variables associated with length of hospital stay (LOS), reoperation, and readmission in patients who underwent a medialization thyroplasty procedure for unilateral vocal cord paralysis. METHODS: Adults who underwent unilateral medialization thyroplasty were identified using the 2017 to 2019 NSQIP databases via Current Procedural Terminology code 31591. Data collected included patient demographics, comorbidities, preoperative labs, American Society of Anesthesiologists classification, inpatient status, operative length, and complications. Univariate and multivariate logistic regression were used to analyze effects on total LOS, reoperation, and readmission. RESULTS: 320 patients were identified, with a mean age of 61 years (95% Cl 59.4-62.7) and a female-to-male ratio of 1.1:1. Forty-two (13.1%) patients reported dyspnea as a preoperative symptom. Seven patients (2.2%) reported postoperative complications, 2 with multiple complications: 2 surgical site infections, 2 pneumonias, 2 unplanned intubations, 2 myocardial infarctions, 1 septic shock, 1 cardiac arrest, 1 ventilator use (>48 h), and 1 acute renal failure. Fifty-one (15.9%) were inpatient procedures, with a mean LOS of 1.43 days (95% CI 0.92-1.94). Preoperative functional status and bilirubin were significantly associated with longer LOS (p < 0.001). There were 6 (1.9%) readmissions and 2 (0.6%) reoperations. In univariate analysis, dyspnea varied with reoperation which is important to note in this patient population with glottic insufficiency. CONCLUSION: Medialization thyroplasty is a procedure with a low risk of mortality. However, preexisting patient comorbidities are associated with an increased risk of postoperative complications and an increased length of stay.

Type I Thyroplasty Is Safe in Patients Undergoing Antithrombotic Therapy.

INTRODUCTION: Type I thyroplasty is one of the most useful surgeries for unilateral vocal fold paralysis. The study objective was to determine whether type I thyroplasty is safe and perioperative antithrombotic management is acceptable in patients undergoing antithrombotic therapy. METHODS: This is a single-hospital retrospective cohort study. The records of 204 patients who underwent type I thyroplasty at a Japanese university hospital, between 2008 and July 2018 were reviewed. We compared the prothrombin time international normalized ratio, prothrombin time, operative time, intraoperative blood loss, and intra- and postoperative complications between patients who did and did not receive antithrombotic therapy. RESULTS: Of 204 patients, 51 (25%) received antithrombotic therapy (antithrombotic group). The remaining 153 patients were assigned to the control group. There were no significant differences in operative time, intraoperative blood loss, or intraoperative complications between the two groups. Sixteen (31%) patients in the antithrombotic group had a hemorrhage or hematoma in the vocal fold mucosa postoperatively, no patient had airway obstruction necessitating tracheostomy, and all patients recovered with follow-up observation only. There were no cases of intraoperative or postoperative complications, such as ischemic heart disease, ischemic stroke, or deep vein thrombosis. CONCLUSION: Type I thyroplasty with careful pre- and postoperative management is safe in patients undergoing antithrombotic therapy.

Transnasal Humidified Rapid Insufflation Ventilatory Exchange (THRIVE) in type 1 thyroplasty.

INTRODUCTION: Transnasal Humidified Rapid Insufflation Ventilatory Exchange (THRIVE) has been shown to benefit oxygenation, ventilation, and upper airway patency in laryngeal surgery. Its use in thyroplasty procedures has not been described. We hypothesized that the addition of THRIVE during type 1 thyroplasty procedures increases patient's safety and decreases the risk of an obstructive airway, while also decreasing the FiO2 with potential pooling of oxygen under the drapes. METHODS: This was a retrospective study of 80 patients carried out at Mayo Clinic Florida. Use of THRIVE for thyroplasty surgeries was introduced by the authors in 2016. All cases between 2016 and 2021 were analyzed. Patients who underwent thyroplasty surgery without the use of THRIVE were included as a control group. RESULTS: A total of 80 patients underwent elective thyroplasty procedures, and 46 of them used the THRIVE technique. Median age was 61 years and 34 % were men. Patients with and without THRIVE were similar at baseline, but THRIVE patients had higher min SPO2 and lower HR end compared to patients without THRIVE. Normal BMI patients had significantly higher min SPO2 compared to either underweight or overweight BMI patients, but there was no strong linear relationship between BMI and intraoperative parameters. CONCLUSION: Our study is the first to demonstrate the use of THRIVE in type 1 thyroplasty in the literature. THRIVE facilitates oxygenation and ventilation of both the spontaneously breathing and the apneic patient. We have demonstrated that thyroplasty can be performed using high flow Optiflow® as the sole mechanism for oxygenation and ventilation.

Long-term voice outcomes of laryngeal framework surgery for unilateral vocal fold paralysis.

OBJECTIVE: To evaluate the short- and long-term voice outcomes after unilateral medialization thyroplasty (MT) and unilateral medialization thyroplasty with arytenoid adduction (MT + AA) in patients with unilateral vocal fold paralysis. METHODS: Voice outcomes were assessed preoperatively, and postoperatively at 3 and 12 months according to a standardized protocol. Voice assessment was performed using Voice Handicap Index (VHI), GRBAS Grade, Maximum Phonation Time (MPT), s/z-ratio and subjective numeric rating scales on voice quality, effort, performance and influence on life. RESULTS: Sixty-one patients were included (34 MT and 27 MT + AA). Significant pre- to postoperative improvements were seen in all voice outcome parameters. No significant differences in post-operative values were identified between the groups. CONCLUSION: Based on our findings, we conclude that patients with unilateral vocal fold paralysis who undergo MT and MT + AA achieve comparable and significant long time voice improvement, although voices do not completely normalize. We also conclude that this does not mean that AA is a superfluous procedure, but can indicate the accurate identification of patients in need of the additional AA procedure based on clinical parameters.

[Laryngeal framework surgery]. / "Laryngeal framework surgery".

Laryngeal framework surgery is an umbrella term for all phonosurgical procedures by which the cartilaginous structure of the larynx and thereby the position and tension of the vocal folds are changed. The aim is to improve the voice. By far the best known and most frequently performed operation is thyroplasty type 1 according to Isshiki, also known as medialization thyroplasty, which is indicated for treatment of glottic insufficiency. Although the first medialization thyroplasty was successfully performed by Payr in Germany in 1915, more than 100 years later, it is still not widely used in Germany.

Precision treatment of post pneumonectomy unilateral laryngeal paralysis due to cancer.

Aim: The aim of this study is to assess the efficacy of external laryngeal medialization acquired through a Gore-Tex implant in a 45 patients affected by unilateral vocal fold paralysis in abduction after pneumonectomy. Method: The cohort of patients was made up of 30 male (73.1%) and 11 female patients (26.9%) with an average age of 66.7 years in a range between 46 and 78 years. Results: The results were analyzed with the objective and subjective analysis of voicing and swallowing. In 95.2% of cases, voice and swallow improvement with statistically significant evidences. Conclusion: We can conclude that Gore-Tex implantation is a simple, reproducible and minimally invasive procedure for management of selected cases of vocal fold unilateral paralysis in the abductory position.

Management of presbyphonia: A systematic review of the efficacy of surgical intervention.

OBJECTIVE: The aging larynx undergoes structural changes that have functional consequences for voice production known as presbyphonia. Treatment of presbyphonia includes voice therapy and surgery. This review seeks to examine voice outcomes after surgery for presbyphonia. DATA SOURCES: Three electronic databases (PreMed, ScienceDirect, Embase) were reviewed for articles published between 1 January 1900 and 1 June 2019. REVIEW METHODS: Original English-language studies examining surgical treatment of presbyphonia in elderly patients (≥65 years) were included according to PRISMA. Two researchers independently analyzed articles. Outcome measures were extracted from and qualitatively compared across studies. RESULTS: Of the 118 articles identified, five satisfied eligibility criteria. In all studies, diagnosis of presbyphonia was based on videostroboscopy. 85 patients (61M, 21F) were evaluated. 37.6% underwent implantation thyroplasty (IT), 48.2% underwent injection augmentation (IA), 7.1% underwent both, and 7.1% underwent basic-fibroblastic growth factor (b-FGF) injection. Average patient age was 71.3 years. Average follow-up time was 5.4 months. Three months post-intervention, IT patients self-reported greater improvement in quality of life (QoL) metrics compared to IA patients. Aerodynamic measures, like mean phonation time, were significantly improved in IT and IA, but not b-FGF-injected patients. All patients experienced improvements in the auditory perception of voice three months post-intervention. CONCLUSION: Surgical modalities currently utilized for presbyphonia include IT and IA, with bFGF-injection being trialed abroad. IT patients reported enhanced QoL relative to IA and bFGF-injected patients. Overall there is a paucity of high-power, prospective studies that explore the efficacy of these modalities. Moreover, wide variability exists in reported outcomes among published studies.

Bilateral medialization thyroplasty in patients with vocal fold atrophy with or without sulcus.

PURPOSE: To evaluate voice outcome after bilateral medialization thyroplasty in patients with non-paralytic glottic insufficiency due to vocal fold atrophy with or without sulcus. METHODS: Retrospective cohort study on 29 patients undergoing bilateral medialization thyroplasty for vocal fold atrophy (14 procedures) or atrophy with sulcus (15 procedures) between October 2012 and November 2017. Voice data were collected and analyzed for the preoperative and the 3- and 12-month postoperative time point according to a standardized protocol, including Voice Handicap Index (VHI)-30 and perceptual, acoustic and aerodynamic parameters. Failure rate was based on number of revisions within 12 months and non-relevant improvement (< 10 points) in VHI-30 at 12 months. RESULTS: There was a clinically relevant (≥ 15 points) and statistically significant improvement (p < 0.0001) in the VHI-30 (preoperative: 55.8 points; postoperative at 12 months: 30.9 points). Fundamental frequency for male subjects decreased significantly from 175 to 159 Hz (p = 0.0001). The pre- and post-operative grade of dysphonia was significantly lower in patients with atrophy compared to atrophy and sulcus (mean difference 0.70, p = 0.017). CONCLUSION: Bilateral medialization thyroplasty is a valid treatment option for patients with atrophy with or without sulcus. Outcomes are comparable to other methods reported in literature. However, there is a great need for larger, prospective studies with long-term follow-up to gain more insight into the comparative voice outcomes for the different forms of surgery for patients with glottic incompetence due to atrophy with or without sulcus.

Modified approach of the anterior commissure for transoral cordectomy in case of difficult exposure: a surgical innovation.

PURPOSE: To propose, in patients presenting a difficult laryngeal exposure, a surgical innovation allowing to perform a transoral laser cordectomy for cancers reaching the anterior commissure or the anterior third of vocal folds (according to the European Laryngological Society classification of laryngeal endoscopic cordectomies). METHODS: Our surgical technique consisted of adding to conventional cordectomies a modified relaxation thyroplasty proposed by Isshiki (type III), also called relaxation thyroplasty by a medial approach in the European Laryngological Society classification system. The anterior commissure retrusion is usually employed in the management of high-pitched voice disorders, but can also allow a better exposure of the anterior commissure. RESULTS: We described here this surgical innovation through the example of our first two patients. For both patients, the definitive histologic analysis showed negative microscopic margins and there was no post-operative complication. There was no need for a tracheostomy. They were allowed to take a normal diet after 2 days and were discharged after 4 days. The voice was breathy and hoarse as expected in case of extended cordectomy. CONCLUSIONS: This surgical innovation corresponding to the addition of an anterior commissure retrusion by a bilateral thyrotomy could be useful in the ELS classification of endoscopic cordectomies. It should allow surgeons to carry out a transoral CO2 laser cordectomy in patients with a T1 and sometimes T2 glottic carcinoma, even with a difficult laryngeal exposure.

Pre- and intraoperative acoustic and functional assessment of the novel APrevent® VOIS implant during routine medialization thyroplasty.

PURPOSE: Persistent unilateral vocal fold paralysis (UFVP) with glottal insufficiency often requires type I medialization thyroplasty (MT). Previous implants cannot be adjusted postoperatively if necessary. The newly developed APrevent® VOIS implant (VOIS) can provide postoperative re-adjustment to avoid revision MT. The objective of this pilot study is to evaluate the VOIS intraoperatively concerning voice improvement, surgical feasibility and device handling. METHODS: During routine MT, VOIS was applied short time in eight patients before the regular implantation of the Titanium Vocal Fold Medialization Implant (TVFMI™). In all patients, perceptual voice sound analysis using R(oughness)-B(reathiness)-H(oarseness)-scale, measurement of M(aximum)-P(honation)-T(ime) and glottal closure in videolaryngoscopy were performed before and after implanting VOIS/TVFMI™. Acoustic analyses of voice recordings were performed using freeware praat. Surgical feasibility, operative handling and device fitting of VOIS and TVFMI™ were assessed by the surgeon using V(isual)-A(nalog)-S(cale). Data were statistically analyzed with paired t test. RESULT: All patients showed significant improvement of voice sound parameters after VOIS/TVFMI™ implantation. The mean RBH-scale improved from preoperative R = 2.1, B = 2.3, H = 2.5 to R = 0.6, B = 0.3, H = 0.8 after VOIS and R = 0.5, B = 0.3, H = 0.8 after TVFMI™ implantation. The mean MPT increased from preoperative 7.9 to 14.6 s after VOIS and 13.8 s after TVFMI™ implantation. VOIS/TVFMI™ achieved complete glottal closure in 7/8 patients. The satisfaction with intraoperative device fitting and device handling of VOIS was as good as that of TVFMI™. CONCLUSION: The novel APrevent® VOIS implant showed similar intraoperative voice improvement compared to routinely used TVFMI™ without adverse device events and with safe device fitting.

Cricopharyngeal myotomy for delayed Cricopharyngeal dysfunction after head and neck surgery - case report.

BACKGROUND: Head and neck surgeries can perturb normal structures of neck muscles and nerve innervations, which are supposed to function in harmony to allow complicated process like swallowing. It is still likely that cricopharyngal dysfunction emerges years after the head and neck surgeries. CASE PRESENTATION: We report a case with history of left unilateral vocal cord immobility and development of dysphagia and aspiration 2 years after radical thyroidectomy with neck lymph nodes dissection and medialization thyroplasty. Cricopharyngeal dysfunction was impressed and was confirmed with visualization of cricopharyngeal narrowing segment in radiographic contrast swallow examination. The patient was treated successfully by cricopharyngeal myotomy, achieving long-term relief in our 4 years of follow up. CONCLUSIONS: Our case of delayed cricopharyngal dysfunction after radical thyroidectomy and medialization thyroplasty shows that it is important to follow up swallowing functions after patients with UVCI undergo medialization thyroplasty. In the event of delayed manifestation of cricopharyngeal function, it can still be treated successfully by cricoharyngeal myotomy, achieving long term relief of dysphagia.

Delayed laryngeal implant infection and laryngocutaneous fistula after medialization laryngoplasty.

BACKGROUND: Medialization laryngoplasty is a common procedure for voice rehabilitation in patients with unilateral vocal fold paralysis. Complications are uncommon and delayed infections involving implants are rare. We report a delayed infectious complication following an animal scratch resulting in a laryngocutaneous fistula. METHODS: Case report. RESULTS: A 73-year-old female underwent a successful and uneventful medialization laryngoplasty for idiopathic unilateral vocal fold paralysis using a silastic implant. More than one year after surgery, she presented with an anterior neck infection following an animal scratch with CT neck findings of a left strap muscle abscess. After incision and drainage, cultures grew methicillin-resistant Staphylococcus aureus. Despite culture-directed antibiotic therapy, the neck continued to drain persistently. Laryngoscopy with stroboscopy revealed a medialized vocal fold with no obvious granulation tissue and normal mucosal pliability. The patient underwent neck exploration revealing a laryngocutaneous fistula. Thus, both the fistulous tract and implant were removed. The wound was closed with a strap muscle advancement into the laryngoplasty window. One month after surgery and antibiotics, the patient had no signs of recurrent neck infection, with a well-healing wound and stroboscopic findings of complete glottic closure, symmetric vocal fold oscillation and acceptable phonation with mild supraglottic compression. CONCLUSIONS: Delayed complications of medialization laryngoplasty are rarely reported. This case demonstrates a delayed infection of a laryngeal implant after an animal scratch requiring implant removal, local tissue reconstruction, and culture-directed antibiotic therapy.

The surgical treatment of unilateral vocal cord paralysis (UVCP): qualitative review analysis and meta-analysis study.

PURPOSE: The objectives of this meta-analysis were to summarize the key surgical procedures for UVCP and to evaluate which of these is associated with better results in terms of vocal improvement. METHODS: A systematic review of the literature was conducted in search of articles focused on the comparison of voice outcome between different techniques for the UVCP treatment. Then, a quantitative analysis was carried out for papers published from 2013 onwards, reporting only adult patients with unilateral paralysis for each study, and each surgical technique was evaluated for its capability of achieving good functional outcomes in terms of GRBAS-I scale and maximum phonation time in seconds (MPT). RESULTS: The search identified 1853 publications. A total of 159 articles were stratified and included according to our selection criteria. 21 out of 159 articles were selected for quantitative synthesis. For trans-oral techniques: the mean GRBAS-I scale were 2.33 before injection and 0.41 after injection. The mean MPT before injection were 4.78 and 12.50 after injection. For open techniques the mean GRBAS-I scale were 2.43 before surgery and 0.68 after surgery. For open technique, the mean MPT were 3.50 before surgery and 12.40 after surgery. CONCLUSIONS: The two types of techniques lead to an improvement in terms of vocal outcomes emphasizing that from the examined literature an indication emerges to perform an early injection because this could reduce the possible need for a more invasive intervention of permanent medialization in the future.