Phonosurgery: indications and pitfalls

Safety and Adverse Events of Medialization Thyroplasty: A Systematic Review

INTRODUCTION

Unilateral vocal fold paralysis or paresis (UVFP) is a condition that causes significant morbidity due to dysphonia, dysphagia, and aspiration. Type I medialization thyroplasty (MT) is the current mainstay surgical treatment for UVFP. Though widely considered a safe procedure, concerns exist over possible airway complications which can lead to overnight observation. Herein, we report a systematic review of the safety and adverse events of MT to aid in determining the safety of same-day discharge.

DATA SOURCES

PubMed and Embase databases.

REVIEW METHODS

Our search identified studies investigating complications associated with MT. Articles were selected if published between January 1, 1989 and March 15, 2023. Abstracts were screened, and data were extracted from included studies. Only Type I MT procedures were included; case reports were excluded. Participant characteristics, intervention details, results, and adverse events were extracted.

RESULTS

The database query identified 751 abstracts, of which 46 studies met eligibility criteria. A total of 2426 patients underwent MT. The most common implant was Silastic (n = 898, 37.0%) followed by Gore-Tex (n = 664, 27.4%). There were 254 (10.5%) total complications reported; 110 (4.5%) were considered major. The most common complication was nonobstructive hematoma (n = 59, 2.4%) followed by hemorrhage (n = 36, 1.5%). Implant extrusion (n = 24, 0.99%) or displacement (n = 15, 0.62%) occurred mostly in Silastic and Gore-Tex implants. Same-day discharge occurred with 429 patients and was not associated with adverse events.

CONCLUSIONS

UVFP can be reliably improved by MT with a low risk of complications. Outpatient MT is a promising treatment with a favorable safety profile. Laryngoscope, 134:1994-2004, 2024.

Endoscopic Rehabilitation of Vocal Cord Paralysis with a Silicone Elastomer Suspension Implant

OBJECTIVES: Because of the side effects of Teflon, the risk of infection from the use of collagen, autologous fat resorption, and the lack of alternative substances, injection laryngoplasty tends to be replaced by laryngeal framework surgery as the method of choice for the treatment of unilateral vocal cord recurrent paralysis (LP). The aim of this study was to evaluate the results, for morbidity and voice quality, of treating this paralysis by injection of a silicone suspension elastomer implant (SSEI).

STUDY DESIGN: The study was retrospective, and 19 patients were included. Average follow-up was 25 months (range: 8.3-43).

METHODS: Each patient underwent clinical and videostroboscopic assessment, and had an electroglottographic recording. Subjective assessment was obtained by self-evaluation. Results were classified as good, fair, or poor, and were based on 2 objective and 3 subjective criteria. A search was made for biologic signs of autoimmune disorders.

RESULTS: Good, fair, and poor results were respectively 79%, 16%, and 5%. Each set of subjective data showed voice improvement ( P < 0.05). The fundamental frequency range, percentage of irregularity, and aspiration decreased significantly ( P < 0.05). There was only one case of postoperative dyspnea, which resolved after steroid injection. No biologic signs of autoimmune disorders were found.

CONCLUSIONS: The use of SSEI is safe. Injection laryngoplasty is easy to perform and avoids cervical scarring. Its results are comparable to those obtained with other techniques, including laryngeal framework surgery, even if there is no standard criterion for the evaluation of voice quality. SSEI injection can reasonably be proposed as a surgical treatment for permanent unilateral vocal cord LP.

Dysphonia secondary to traumatic avulsion of the vocal fold in infants

OBJECTIVE

Airway compromise due to paediatric intubation injuries is well documented; however, intubation injuries may also cause severe voice disorders. We report our experience and review the world literature on the voice effects of traumatic paediatric intubation.

CASE SERIES

We report five cases of children referred to Great Ormond Street Hospital for Children who suffered traumatic avulsion of the vocal fold at the time of, or secondary to, endotracheal intubation. All children had significant dysphonia and underwent specialist voice therapy.

CONCLUSIONS

The mechanisms of injury, risk factors and management of the condition are discussed. Children suffering traumatic intubation require follow up throughout childhood and beyond puberty as their vocal needs and abilities change. At the time of writing, none of the reported patients had yet undergone reconstructive or medialisation surgery. However, regular specialist voice therapy evaluation is recommended for such patients, with consideration of phonosurgical techniques including injection laryngoplasty or thyroplasty.

A-P positioning of medialization thyroplasty in an excised larynx model

HYPOTHESIS

Posterior positioning of medialization thyroplasty provides the best acoustic and aerodynamic outcomes.

STUDY DESIGN

Ex vivo excised canine larynx.

METHODS

Unilateral thyroplasty windows were cut in the thyroid cartilages of 10 excised canine larynges. Each larynx was mounted on an artificial lung and the vocal fold opposite the thyroid window was adducted by medializing its arytenoid cartilage. Then, medialization thyroplasty was simulated with a probe placed anterior, central, and posterior in the thyroid window. The glottal area, airway reduction, medialization force, phonation threshold pressure and flow, aerodynamic power, intensity, efficiency, jitter, shimmer, and signal-to-noise ratio (SNR) were measured at each medialization position.

RESULTS

Posterior medialization probe placement minimized the glottal area, provided the best voice as determined by perturbation measures and SNR, reduced the work of phonation, and increased efficiency. Anterior and middle probe placement minimized the work of phonation but provided only modest gains in sound quality and decreased sound intensity. Medializing the vocal fold with posterior probe placement required twice as much force as central and anterior probe placement.

CONCLUSIONS

The results suggest that posterior medialization provides the greatest improvement in acoustic parameters and efficiency in patients who can tolerate the airway reduction. Middle and anterior medialization can decrease work of phonation, but in this experiment objective improvement in sound quality was limited. Subtle changes in displacement shim contour, especially in middle and anterior locations, have a substantial impact on voice outcome, affirming the value of intraoperative voice assessment.

Perspectives on medialization laryngoplasty

Medialization laryngoplasty has become the new gold standard for the permanent management of patients with vocal fold paralysis and paresis. This article reviews the conceptual developments of the diagnosis and management of patients with vocal fold paresis and paralysis. We identify the specifics of operative decision-making as well as surgical complications associated with medializationlaryngoplasty. The role of revision surgery is detailed. We suggest a standardized evaluation using both objective and subjective data for analysis of surgical outcomes.

AUTOLOGOUS FAT INJECTION LARYNGOPLASTY FOR UNILATERAL VOCAL FOLD PARALYSIS

BACKGROUND

Fat injection laryngoplasty has been used at the Sydney Voice Clinic for selected cases of unilateral vocal fold paralysis since 1989.

METHODS

Forty-five consecutive cases deemed suitable for treatment by this technique are presented in this paper.

RESULTS

Mean follow up for this group of patients was 33 months. Over the period of follow up, 39 of the 45 patients achieved normal or near normal voice, with four patients requiring additional surgical intervention.

CONCLUSION

Fat injection laryngoplasty is a quick, simple, inexpensive and reliable procedure, with few complications and good long-term results in suitable selected cases of unilateral vocal fold paralysis.

Palatal adhesion: the treatment of unilateral palatal paralysis after high vagus nerve injury

BACKGROUND

Resection of skull base tumors commonly necessitates intraoperative sacrifice of lower cranial nerves at the level of the jugular foramen. Sequelae of unilateral vagus nerve loss include ipsilateral laryngeal paralysis, ipsilateral palatal and pharyngeal paralysis, and velopharyngeal incompetence (VPI) marked by hypernasal speech and nasopharyngeal reflux of liquids during swallowing.

METHODS

Palatal adhesion (PA), a procedure whereby the unilaterally paralyzed palate is attached to the posterior pharyngeal wall, decreases the size of the velopharyngeal port and minimizes the symptoms. This study assessed the outcome of PA in 31 patients with VPI secondary to proximal vagus nerve injury.

RESULTS

PA decreased postoperative nasality in 96% of patients. Nasopharyngeal reflux was significantly improved in 83%. Three patients (11%) had minor wound breakdown postoperatively, all of which healed completely with conservative management.

CONCLUSION

PA offers a favorable result with minimal concomitant morbidity and is recommended for patients with VPI secondary to unilateral proximal vagus nerve paralysis.

Management of vocal fold scar with autologous fat implantation: perceptual results

Vocal fold scar disrupts the mucosal wave and interferes with glottic closure. Treatment involves a multidisciplinary approach that includes voice therapy, medical management, and sometimes surgery. We reviewed the records of the first eight patients who underwent autologous fat implantation for vocal fold scar. Information on the etiology of scar, physical findings, and prior interventions were collected. Videotapes of videostroboscopic findings and perceptual voice ratings [Grade, Roughness, Breathiness, Asthenia, Strain (GRBAS)] were randomized and analyzed independently by four blinded observers. Etiology of scar included mass excision (7), vocal fold stripping (3), congenital sulcus (2), and hemorrhage (1). Prior surgical procedures performed included thyroplasty (1), autologous fat injection (9), excision of scar (2), and lysis of adhesions (2). Strobovideolaryngoscopy: Statistically significant improvement was found in glottic closure, mucosal wave, and stiffness (P = 0.05). Perceptual ratings (GRBAS): Statistically significant improvement was found in all five parameters, including overall Grade, Roughness, Breathiness, Asthenia, and Strain (P = 0.05). Patients appear to have improved vocal fold function and quality of voice after autologous fat implantation in the vocal fold. Autologous fat implantation is an important adjunctive procedure in the management of vocal fold scar, and a useful addition to the armamentarium of the experienced phonomicrosurgeon.

Arytenoid adduction and medialization laryngoplasty

Arytenoid adduction and medialization laryngoplasty have become the mainstay of static surgical rehabilitation of the larynx after vocal fold paralysis. The rationale for considering one versus a combination of the two procedures has not been well addressed. This article outlines the basic science of the procedures and the clinical technical modifications necessary to make the surgery easier.

Airway compromise in thyroplasty surgery

OBJECTIVES

Airway compromise arising from thyroplasty procedures including Isshiki type I through IV thyroplasties, arytenoid adduction, and arytenoid fixation is uncommon yet potentially life threatening. Identification of incidence of obstruction and probable causes is important for preoperative planning, consultation, and postoperative care.

STUDY DESIGN

Retrospective review of all thyroplasty operations, including arytenoid adduction and arytenoid fixation.

METHODS

Three hundred thirty-two patients underwent a total of 630 thyroplasty procedures. Detailed information was gathered on patients manifesting symptoms of airway obstruction.

RESULTS

Seven patients required an unplanned tracheostomy for airway compromise. Five of 143 patients who underwent arytenoid adduction required a tracheostomy, for an incidence of 3.5%. The median interval to developing significant stridor requiring tracheostomy was 9 hours, with five of these seven patients requiring airway surgery within the first 18 postoperative hours. No patient receiving a type I thyroplasty alone developed significant airway compromise. Tracheostomy was required in two patients with underlying neuromuscular disease-one who underwent a bilateral type I thyroplasty and one who underwent an arytenoid fixation procedure.

CONCLUSION

The percentage of airway complications after thyroplasty is low. However, arytenoid adduction and fixation operations have a significant risk of postoperative temporary tracheostomy and warrant preoperative discussion regarding tracheostomy and postoperative overnight hospital admission.

Computerized tomographic alignment of silastic implant in type 1 thyroplasty

PURPOSE

We designed a computerized tomography (CT)-based silastic implant preparation method that enabled custom fit to the individual size of the patient's larynx for medialization laryngoplasty.

MATERIALS AND METHODS

Three women with unilateral vocal cord paralysis underwent type I thyroplasty operation. The individual size of the patient's larynx was determined by preoperative measurements on CT scan and the implant was prepared accordingly. The implant was then inserted through a rectangular window at the level of vocal cords which had been outlined according to CT findings.

RESULTS

Three patients, who were age 41, 25, and 37 years, underwent medialization laryngoplasty by this technique. They were followed up for 37, 16, and 4 months, respectively. There was not any rejection reaction, and satisfactory functional results with 10, 7, and 9 seconds of phonation duration have been achieved, respectively.

CONCLUSION

In this technique, the desired medialization of the paralyzed vocal cord was accomplished by the first insertion of the implant. Thus, the duration of the operation and the vocal cord edema aroused by manipulation of the inner perichondrium and internal laryngeal structures were reduced.

Unilateral vocal fold paralysis: causes, options and outcomes

BACKGROUND

This study presents the current aetiology of and management options for vocal fold paralysis.

METHODS

One hundred and eight patients with unilateral vocal fold paralysis, managed by The Sydney Voice Clinic from 1989 to 1996, are reviewed. Aetiology of the palsy was classified as iatrogenic (45 of 108), idiopathic (36 of 108) and other defined causes (27 of 108). Nineteen patients were observed with the rest being managed with speech therapy alone (38 of 108), surgery (24 of 108) or surgery with adjuvant speech therapy (27 of 108). Surgical techniques included vocal fold augmentation (n = 43), thyroplasty (n = 20) and laryngeal re-innervation (n = 12).

RESULTS

Overall 78 of 108 patients had restoration of near normal to normal voice with an additional 14 attaining a very good voice or better (voice outcome <2).

CONCLUSIONS

Early intervention for symptomatic patients was found to be rewarding and safe. Vocal fold augmentation with autologous fat was particularly successful in achieving sustained improvement of voice.

Effect of thyroplasty on laryngeal airflow

Thyroplasty has virtually replaced Teflon injection as the procedure of choice for treatment of the unilateral paralyzed vocal cord. Previous studies have shown that Teflon injection, by stiffening the vocal cord, decreases the extrathoracic airway obstruction occasionally measured by pulmonary function testing in patients with unilateral vocal cord paralysis. We became interested in the effect of thyroplasty on extrathoracic airflow. In this prospective study, patients underwent prethyroplasty and postthyroplasty pulmonary function testing. Flow volume loops combined with traditional spirometry were used. Postoperative pulmonary function tests were performed at least 2 months after surgery to allow resolution of surgical edema. Our study results support the previous finding that vocal cord paralysis alone causes some degree of extrathoracic obstruction. However, in contrast to Teflon injection, thyroplasty decreased extrathoracic airflow in all but 1 patient, and by criteria based on the ratio of the midexpiratory flow to the midinspiratory flow, caused new postoperative extrathoracic obstruction in 27% of patients. Symptomatic evidence of this obstruction may be more evident in those active patients with more ventilatory demand.

Clinical experience with Gore-Tex for vocal fold medialization

OBJECTIVES/HYPOTHESIS

Present clinical experience with vocal fold medialization under local anesthesia using a Gore-Tex implant. The procedure consists of placing the implant into a pocket formed by dissection of the inner perichondrium of the thyroid cartilage through a small window made in the thyroid ala.

STUDY DESIGN

During 2 years, we used this technique preferentially in 13 of the 16 cases of vocal fold medialization (three patients underwent Teflon injection because of a contraindication to local anesthesia). Follow-up was longer than 3 months in 11 cases (mean, 13 mo).

METHODS

Vocal result was analyzed by the means of perceptual analysis and by the measurement of jitter factor. Glottal leakage was evaluated perceptually using videolaryngoscopy, and oral airflow was measured during the production of a vowel. In cases with preoperative aspiration, videofluoroscopy was performed.

RESULTS

Implantation was successful in all but one patient in whom extrusion of the implant material occurred. In the latter case, the implant was removed and the patient recuperated his preoperative voice without any other complication. In the 10 other cases, voice improvement assessed by perceptual and objective evaluation was satisfactory.

CONCLUSIONS

Results compare favorably with those of endoscopic techniques using Teflon or collagen and laryngeal frame surgery techniques using silicone or cartilage. We 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.

Ablation of Teflon granulomas in the canine larynx with the free-electron laser

This study develops a canine model for the treatment of laryngeal Teflon granulomas and demonstrates endoscopic ablation using the free-electron laser (FEL) set at a wavelength of 8.5 microm. Laryngeal Teflon granulomas may cause dysphonia and airway obstruction, and they are difficult to remove. The infrared absorption spectrum of Teflon reveals a strong absorption peak centered at 8.5 microm. In this study, 12 dogs had the right vocal cord injected with Teflon paste. Two months later, Teflon granuloma formation was confirmed histologically. Laser incisions into the granulomas were performed at 3 different wavelengths: 7.4 microm (FEL), 8.5 microm (FEL), and 10.6 microm (carbon dioxide laser). Histopathologic analysis was performed at 1 week and 6 weeks after the laser incisions. The FEL at the 8.5-microm wavelength was found to optimally ablate the Teflon granulomas, but the granulomas persisted in the specimens treated with 7.4 microm (FEL) and 10.6 microm (carbon dioxide laser).

Biomechanics of combined arytenoid adduction and medialization laryngoplasty in an ex vivo canine model

Arytenoid adduction (AA) and medialization laryngoplasty (ML) are being performed concurrently in patients with unilateral vocal fold paralysis with a large posterior glottal gap. The biomechanical effects of this combined procedure on the larynx have not been studied. An excised canine larynx model was used to study the effects of AA, ML, and combined AA and ML (AA-ML) on vocal fold configuration (length and degree of medialization) and tension. AA-ML lengthens the affected vocal fold relative to the opposite vocal fold, although both were slightly shortened compared with the control state (nonsignificant trends). AA-ML medializes the entire length of the vocal fold more effectively than AA or ML alone. Midmembranous vocal fold tension did not increase with AA-ML. With AA-ML, the vocal process resisted significantly greater lateralizing forces than with the control state or ML. We conclude that in an excised canine model, AA-ML combines the biomechanical properties of AA and ML. The larynx appears to be divided into 2 biomechanical subunits: membranous vocal fold (anterior) and arytenoid cartilage (posterior). When surgical rehabilitation of both laryngeal subunits is required, AA-ML appears to be a better choice than AA or ML alone.

Bilateral medialization laryngoplasty

OBJECTIVES

To present indications, techniques, and results of bilateral medialization laryngoplasty (BML).

STUDY DESIGN

Retrospective review of 39 consecutive patients who had BML for correction of glottal insufficiency attributable to presbylaryngis (n = 16), bilateral vocal fold paresis (n = 13), unilateral paralysis with contralateral bowing (n = 4), and other miscellaneous neurologic diseases (n = 6).

METHODS

Complete preoperative and postoperative clinical and acoustical data were analyzed for 74% (29/39) of the subjects. All 39 subjects completed a patient survey to assess their long-term outcomes.

RESULTS

Overall, 90% (35/39) of the patients who had BML experienced significant improvement in voice and swallowing function. Subsequently, 36% (14/39) of the patients underwent adjunctive lipoinjection for closure of small residual glottal gaps (vocal "fine-tuning"). Of the BML patients (with or without lipoinjection) who had complete preoperative and postoperative voice data, 83% (24/29) had complete glottal closure after surgery, resulting in normal or near-normal voices. Eighty-five percent (33/39) of the patients responded that they "would have surgery again." Of the six patients who said that they would not have surgery again, three had good results and one had progressive neurologic disease. The mean duration of follow-up was 17 months.

CONCLUSIONS

BML is an effective rehabilitative surgical treatment for symptomatic vocal fold bowing. In addition, lipoinjection is useful as an adjunct to BML to enhance the voice outcome in selected cases.

The biomechanics of the medialization laryngoplasty (thyroplasty type 1) in an ex vivo canine model

The biomechanics of medialization laryngoplasty are not well understood. An excised canine larynx model was used to test the effects of various sized silicon implants. The vocal fold length, position, and tension were measured. Medialization laryngoplasty did not affect vocal fold length. At the mid-membranous vocal fold, larger shims resulted in greater medialization and tension. Medialization laryngoplasty neither medialized nor stiffened the vocal process to resist lateralizing forces. We conclude that medialization laryngoplasty provides bulk and support for defects of the membranous region of the vocal fold, but does not appear to close a posterior glottal gap. The selection of a surgical procedure to treat glottal incompetence should take into account the unique biomechanical properties of the anterior (membranous vocal folds) and posterior (cartilaginous portion) glottis.

Ablation of teflon granuloma with the free-electron laser emitting in the eight- to nine-micron range

In this study, we developed a rat model for Teflon granuloma and used this model to evaluate the removal of the granuloma at laser wavelengths at which Teflon has a maximal absorption. Twenty-four Teflon granulomas were created in 12 rats, and the gross and histologic effects from laser incision at four different wavelengths (8.25, 8.5, 8.75, and 10.6 microm) were evaluated acutely and at 7 and 14 days postoperatively. Polytetrafluoroethylene, or Teflon, is a relatively inert substance that has been used over the past 4 decades for endoscopic injection into the thyroarytenoid muscle of the larynx for the purposes of laryngeal rehabilitation in cases of unilateral vocal fold paralysis or incomplete glottic closure. In certain cases in which formation of granulomatous reaction to the Teflon occurs, patients may have significant dysphonia or airway compromise. Once Teflon has infiltrated the surrounding tissue planes, it is exceedingly difficult to remove endoscopically. Endoscopic removal of this granuloma is usually attempted with the carbon dioxide (CO2) laser and has had limited success. Examination of the infrared absorption spectrum of polytetrafluoroethylene reveals strong absorption in the mid-infrared region in the 8- to 9-microm range, with minimal absorption at 10.6 microm. Therefore, this absorption spectrum predicts a more efficient vaporization of Teflon at wavelengths near 8.5 microm. Using the free-electron laser to generate 8.25-, 8.5-, and 8.75-microm laser light, we found Teflon granuloma ablation was far superior to CO2 laser ablation at 10.6 microm. The 8.25-, 8.5-, and 8.75-microm wavelengths selectively ablated Teflon granuloma with minimal to no collateral thermal injury to tissue. The differences in thermal effects observed while actually using the lasers were confirmed histologically.

Vocal evaluation of thyroplasty type I in the treatment of nonparalytic glottic incompetence

This study investigated the prethyroplasty and postthyroplasty voices of patients with glottic incompetence of mobile vocal folds related to vocal fold bowing and scarring. Seventeen patients underwent vocal function evaluation preoperatively and 1 month postoperatively with videostrobolaryngoscopic examination, acoustic and aerodynamic analysis, and perceptual judgment of voice characteristics. The postoperative voice outcome in this group of patients was compared to that of a group of patients with unilateral vocal fold paralysis. Patients with vocal fold bowing showed significant improvement in glottic gap size and hoarseness after the surgery. There was minimal improvement on other test measures. Patients with vocal fold scarring exhibited worse preoperative and postoperative vocal functions, with little voice improvement after surgery. The outcome of thyroplasty type I in cases of vocal fold bowing or scarring is not as good as that in unilateral vocal fold paralysis.

Longitudinal evaluation of vocal function after thyroplasty type I in the treatment of unilateral vocal paralysis

This study investigated longitudinal changes of vocal efficiency and stability after primary thyroplasty type 1. Fifty-three patients with unilateral vocal-fold paralysis underwent vocal-function evaluation preoperatively and at periodic intervals of 1, 3, and 6 months postoperatively. Vocal-function assessment included videostrobolaryngoscopic examination, acoustical and aerodynamic analysis, and perceptual judgment of voice characteristics. Parameters that included glottic-gap size, maximum phonation time, glottic-flow rate, jitter, harmonic/noise ratio, breathiness, hoarseness, loudness, and phrasing showed significant improvement after thyroplasty and remained stable as early as 1 month postoperatively, with only slight fluctuations over a 6-month period. Postoperative voice outcome was not affected by age, sex, duration of vocal symptoms, cause of paralysis, or preoperative pulmonary function.

A comparison of type I thyroplasty and arytenoid adduction

Glottal incompetence is a common laryngeal disorder causing impaired swallowing and phonation. The resultant voice has been characterized as weak and breathy with a restricted pitch range. Currently, medialization thyroplasty and arytenoid adduction are two of the surgical treatments for patients with glottal incompetence. However, few studies have evaluated the changes in objective measures of speech with type I thyroplasty and arytenoid adduction. In this study, 59 patients with glottal incompetence underwent either type I thyroplasty or arytenoid adduction. Acoustic (jitter, shimmer, and harmonics-to-noise ratio) and aerodynamic (airflow, subglottic pressure, and glottal resistance) measures were obtained both pre- and postoperatively. No significant differences were found among acoustic or aerodynamic measures for operation type. However, a significant pre/postsurgery effect was observed for translaryngeal airflow. In addition, no significant differences were found among the measures for patients with traditional compared with nontraditional operative indications. Patients who developed glottal insufficiency due to previous laryngeal surgery (e.g., vocal fold stripping) demonstrated no statistically significant improvement in acoustic or aerodynamic measures following thyroplasty or arytenoid adduction.

Vocal fold medialization using autologous cartilage in a canine model: a preliminary study

Unilateral vocal fold paralysis can alter phonation. Medialization of the vocal fold using cartilage augmentation dates to the early 1950s. Improved phonation after cartilage chordal augmentation has been reported, but no study has as yet documented cartilage viability or size in this setting over time. The authors of this study evaluated thyroid alar cartilage as a medializing material in three mongrel dogs. Grafts were inserted lateral to the inner thyroid perichondrium at the vocal fold level via a window in the thyroid cartilage. Changes in weight, size, and volume were assessed 6 months after implantation. The average graft weight declined by 15%, and the average square area declined by 3%. Importantly, the average volume maintained was 87%. The grafts remained rigidly fixed to the thyroid cartilage in their placement positions. Histologic examination documented minimal resorption. The data suggest that thyroid alar cartilage is a viable filler in type I thyroplasty procedures.

Anaesthesia for thyroplasty

The purpose of this report is to describe the anaesthetic considerations for layngoplastic procedures. Thyroplasty is a procedure which restores the voice in unilateral vocal cord paralysis. The procedure employs an external approach via a window cut at the appropriate level in the thyroid ala. A wedge of silastic is inserted against the inner perichondrium, thereby displacing the vocal cord medially and permitting voice production. Correct placement of the implant is assessed by asking the patient to phonate; patient cooperation is therefore necessary at certain times during the procedure. We describe our management of a patient undergoing thyroplasty. The use of a benzodiazepine agonist-antagonist combination provided both optimal operating conditions and patient comfort.

Teflon granuloma of the larynx: etiology, pathophysiology, and management

Intralaryngeal Teflon injection for correction of unilateral vocal cord paralysis is known to produce a foreign body giant cell reaction. In our practice, we have seen increasing numbers of patients who had developed dysphonia related to Teflon injection. This patient series was reviewed, as were the surgical technique to correct this condition, voice results, and acoustic analysis of a subset of the patient series. We conclude that dysphonia, secondary to Teflon injection, can be either from overinjection of Teflon or inappropriate injection, or from the proliferative granulomatous response of the larynx to the Teflon. Our technique of laser incision into the superior aspect of the Teflon implant, followed by vaporization and preservation of a margin of mucosa of the cord medially, resulted in improved voice in 8 of 11 patients treated in this manner. Acoustic and aerodynamic analyses reveal significant deficits in vocal function that may persist after procedures used to correct this condition.

Magnetic resonance imaging (MRI) assessment of vocal fold medialization surgery

Historically, clinicians have used subjective assessment and perceptual judgments, supplemented with acoustic measures, aerodynamic studies, and videostroboscopy, to determine the effects of phonosurgery. When phonosurgical results are poor, magnetic resonance imaging (MRI) can be useful in determining how the surgical modifications contributed to the anatomical and functional status of the vocal folds. The authors present examples of MRI following vocal fold medialization by injection, thyroplasty, and arytenoid adduction. Findings reveal that the superior contrast resolution of MRI can precisely identify placement and persistence of injected implants and is particularly helpful in showing effects of the size and shape of alloplastic prostheses on vocal fold displacement. Such information is useful in troubleshooting suboptimal results and in planning revision thyroplasty by defining modification in the design of prostheses and the placement of cartilaginous windows in medialization thyroplasty. MRI can also aid in confirming indications for and limitations of certain procedures.

Thyroplasty type I for unilateral vocal cord paralysis

Unilateral vocal cord paralysis may occur with trauma, neoplasms, mechanical or central nervous system dysfunction, or following extensive aortic and mediastinal vascular surgery or thyroidectomy. Thyroplasty type I is a form of laryngeal framework surgery (ie, phonosurgery) used to treat unilateral vocal cord paralysis. A silicone implant is placed inside a surgically created window in the thyroid cartilage and pushes the paralyzed cord medially, allowing the moving cord to touch the paralyzed cord and close the opening. The procedure is performed under monitored local anesthesia with sedation so the patient can phonate during the procedure. Airway compromise is the main complication associated with this procedure.

Three-dimensional motion of the arytenoid adduction procedure in cadaver larynges

To determine whether variation in suture placement could improve the results of the arytenoid adduction procedure, a model was developed using fresh human cadaver larynges. Three-dimensional (3-D) motion of the arytenoid was determined by utilizing computed tomographic imaging with radiopaque markers on the apex and muscular and vocal processes. By utilizing principles previously applied to the study of rigid body mechanics for the carpal, knee, and tarsal joints, rotation and translation of the arytenoid about the axial, coronal, and sagittal axes were calculated. Subglottic airflow resistance was measured before and after the procedure. Posterior glottic closure was reproducibly achieved, as determined by computed tomographic imaging and airway resistance. Conflicting reports on cricoarytenoid joint mechanics can be attributed to reliance on trigonometric analysis of two-dimensional images, which results in errors in out-of-plane motion. This paper presents a useful model for obtaining detailed anatomic information describing arytenoid 3-D motion.

Precise vocal cord medialization using an adjustable laryngeal implant: a preliminary study

Treatment of symptomatic unilateral vocal cord paralysis is most frequently surgical. Medialization of the vocal cord using Teflon injection has proved effective; however, studies have shown this technique to produce stiffness of the vocal fold with loss of the "mucosal wave" and concomitantly poor vocal function. As well, overcorrection may occur and is not reversible. Isshiki type 1 medialization thyroplasty has been shown to produce a substantial improvement in vocal quality, as well as preserve the mucosal wave. A number of problems encountered during the performance of Isshiki type 1 thyroplasty has led us to modify the original technique. We have developed a new implant that allows for precise, easily adjustable control of vocal cord medialization. To evaluate the degree of vocal cord medialization afforded by this implant, larynges of fresh male and female cadavers were used as an experimental model. In both larynges, vocal cord medialization was shown to occur in a predictable fashion for the anterior, middle, and posterior segments, as well as in the functionally important inter-arytenoid region. We believe the use of this implant in medialization thyroplasty will allow precise, atraumatic medialization of the paralyzed vocal cord. This greater control over positioning and ease of adjustment should contribute to enhanced vocal quality.

Difficulties in endoscopic removal of Teflon granulomas of the vocal fold

The difficulties in treating granulomas resulting from Teflon injection into the vocal fold are underreported in the literature. We have reviewed our experience with nine patients undergoing 27 procedures for Teflon granuloma. Two patients required tracheotomy before undergoing endoscopic granuloma removal because of airway compromise, and a third required urgent tracheotomy following endoscopy. One of the patients requiring elective tracheotomy had a granuloma that extended across the midline to the contralateral arytenoid, causing its fixation. Arytenoidectomy was required for decannulation in this patient. In all but one patient the granuloma nearly completely replaced the thyroarytenoid muscle. This extensive involvement often precludes the adequate excision of the granuloma in a single procedure; however, the microflap technique allows mucosal preservation to facilitate future procedures. In some cases the granuloma destroys large amounts of mucosa, and a microflap cannot be elevated and saved. The difficulties of excision are related to the near-total replacement of the thyroarytenoid muscle by granuloma. This paper will help the otolaryngologist--head and neck surgeon understand this destructive process and the resulting difficulties in surgical rehabilitation.

Silastic medialization and arytenoid adduction: the Vanderbilt experience. A review of 116 phonosurgical procedures

From April 1987 to April 1992, 116 phonosurgical procedures were performed to treat glottal incompetence. The initial numbers of these surgical procedures included the following: 29 primary Silastic medializations, 3 primary Silastic medializations with arytenoid adduction, 53 secondary Silastic medializations, 4 secondary Silastic medializations with arytenoid adduction, and 11 bilateral Silastic medializations. These procedures are useful in treating unilateral true vocal cord paralysis, scarring, bowing, or paresis, as well as bilateral true vocal cord bowing. Of the initial 100 patients, 16 later underwent a revision with either a larger implant's being placed or an arytenoid adduction. Primary Silastic medialization is the placement of an implant under general anesthesia in the same surgical setting in which laryngeal innervation is sacrificed. Secondary Silastic medialization is the placement of an implant under local anesthesia for a preexistent vocal cord malfunction. In either case, overall voice results for unilateral paralysis are very good. Primary Silastic medialization significantly decreases the postoperative rehabilitation period in skull base patients because of the immediate postoperative glottal competence and decreased use of perioperative tracheotomy. Bilateral implants yielded good results in 6 patients with presbylaryngis, but 6 other patients with bowing from other causes experienced only moderate improvement in speech quality. There were no implant extrusions; however, 1 implant was removed secondary to a persistent laryngocutaneous fistula in a patient who had previously undergone laryngeal irradiation. This was the only complication in this series.

Acoustic characteristics of post-thyroplasty patients

This study investigated changes in voice quality after thyroplasty type I in eight adults with unilateral vocal fold paralysis. A silicone rubber implant was inserted through a window in the thyroid ala and placed between the inner and outer perichondrium to externally medialize the abducted vocal fold. Measures of fundamental frequency (vocal pitch), pitch range, maximum phonation time, s/z ratio, pitch perturbation (vocal jitter), and amplitude perturbation (vocal shimmer) were made 1 to 2 weeks preoperatively and 1 month postoperatively. Postoperative voice quality was characterized by an improved pitch range, phonation time, s/z ratio, and pitch and amplitude perturbation. No change was noted in fundamental frequency. Changes in postoperative voice quality were unrelated to the subjects' preoperative age, sex, etiology, and duration of the paralysis.

Teflon versus thyroplasty versus nerve transfer: a comparison

Surgical rehabilitation of the paralyzed larynx is currently performed by Teflon injection, thyroplasty, and reinnervation techniques. Proponents of the two newer techniques maintain that they are preferred to Teflon injection because superior phonatory quality is achievable. This paper was written in an attempt to dissect the issues regarding this question. Teflon remains the quickest and least expensive procedure, but further experience with stroboscopic and other voice analyses reveals that the other procedures demonstrate some superiority in phonatory quality over Teflon. In this author's hands, the nerve transfer offers the best opportunity to achieve a normal phonatory voice. In addition, it is the only one of the three procedures that leaves the vocal cord entirely undisturbed--important in the event one of the other two procedures becomes necessary.