Revision laryngoplasty

Subject-Specific Modeling of Implant Placement for Type I Thyroplasty Surgery

Type I thyroplasty is widely used to improve voice production in patients affected by unilateral vocal fold paralysis. Almost two-thirds of laryngologists report using Silastic® implants to medialize the vocal fold, with implant size, shape, and location determined experientially. However, post-surgical complications arising from this procedure (extrusion, migration, resizing) necessitate revision in 4.5-16% of patients. To improve initial surgical outcomes, we have developed a subject-specific modeling tool, PhonoSim, which uses model reconstruction from MRI scans to predict the optimal implantation location. Eleven vocal fold sample sides from eight larynges of New Zealand white rabbits were randomized to two groups: PhonoSim informed (n = 6), and control (no model guidance, n = 5). Larynges were scanned ex vivo in the abducted configuration using a vertical-bore 11.7 T microimaging system, and images were used for subject-specific modeling. The PhonoSim tool simulated vocal fold adduction for multiple implant location placements to evaluate vocal fold adduction at the medial surface. The best implant placement coordinates were output for the 6 samples in the PhonoSim group. Control placements were determined by the same surgeon based on anatomical landmarks. Post-surgical MRI scans were performed for all samples to evaluate medialization in implanted vocal folds. Results show that PhonoSim-guided implantation achieved higher vocal fold medialization relative to controls (28 to 55% vs. - 29 to 39% respectively, in the glottal area reduction), suggesting that this tool has the potential to improve outcomes and revision rates for type I thyroplasty.

One hundred years of external approach medialisation thyroplasty

It has been 100 years since Erwin Payr first developed an operation to improve the effects of a paralysed vocal fold, and operations based on this technique are still in use today. This technique, medialisation thyroplasty, aims to improve the symptoms caused by vocal fold palsy by realigning the lateralised vocal fold into the midline.

Whilst the effects of vocal fold palsy were recognised in antiquity, it was only with the development of indirect laryngoscopy in the late nineteenth century that the vocal fold paralysis could be identified as an aetiology for poor phonation and dysphagia. Payr, in 1915, was the first to perform a recognisable form of medialisation thyroplasty, which was further developed in the early twentieth century, but medialisation thyroplasty did not begin to be widely used until the development of the modern technique by Isshiki et al., in 1974.

Since then, medialisation thyroplasty has continued to be developed and is currently the most widely used technique for correcting the effects of vocal fold palsy. However, a wide array of therapeutic options is now available for vocal fold palsy and it is impossible to say whether or not medialisation thyroplasty will still be used in another 100 years.

Revision Gore-Tex Medialization Laryngoplasty

OBJECTIVE: To evaluate the indications, results, and safety of revision Gore-Tex medialization laryngoplasty (GML).

METHODS: A retrospective chart review of 156 patients that underwent GML procedures between the years 1998–2002. Study population consisted of those patients who required revision surgery for any reason.

RESULTS: Sixteen patients required 22 revision procedures. Indications for revision were divided into 2 groups, complications and glottal closure problems. Complications included extruded or displaced implants (n = 4). The most common glottal closure problem was undercorrection (n = 9). Others included anterior overcorrection (n = 1) and persistent posterior glottal gap (n = 2). Revision procedures included GML (n = 9), injection augmentation (n = 9), endoscopic implant removal (n = 2), and arytenoid adduction (n = 2). In patients with glottal closure problems, the GCI improved in all 10 and the voice rating scale improved in 9.

CONCLUSION: Reasons for revision of GML are variable, the most common being undercorrection. A variety of safe, effective revision techniques are available with a high success rate.

Revision Transcervical Medialization Laryngoplasty for Unilateral Vocal Fold Paralysis

Objective

To identify patterns of failure following transcervical medialization laryngoplasty for unilateral vocal fold paralysis and describe indications and revision techniques for optimal vocal outcomes.

Study Design

Case series with chart review.

Setting

Tertiary care center.

Subjects and Methods

Thirty-nine consecutive patients between January 2005 and April 2014 undergoing transcervical revision of failed primary medialization laryngoplasty were identified. Demographics, etiology, stroboscopic assessment, and surgical techniques were recorded. Patient self-assessment using the Voice-Related Quality-of-Life (VRQOL) questionnaire and objective acoustic and aerodynamic assessments performed pre- and postoperatively were analyzed using t tests for paired comparisons.

Results

Thirty-nine patients underwent 48 transcervical revision surgeries. Median follow-up was 14.6 months from time of final revision surgery. Indications included anterior glottic incompetence (38/48, 79%), posterior glottic incompetence (20/48, 42%), glottic overclosure (8/48, 17%), and/or decreased phonatory pliability (12/48, 25%). A combination of findings was present in 21 (44%) surgeries. Revision techniques included either anterior augmentation, arytenopexy, and cricothyroid subluxation (alone or in combination) in 46 of 48 (96%) patients or partial implant removal alone in 2 patients. Seven patients (18%) required multiple revisions. A complete set of voice parameters was available for 22 patients, and statistically significant improvements included VRQOL scores, fundamental frequency in females, jitter, noise-to-harmonic ratio, and mean airflow rate.

Conclusion

Patterns of failure in patients with suboptimal phonatory function after transcervical medialization laryngoplasty included persistent glottic incompetence, glottic overclosure, and decreased vocal fold pliability. Revision transcervical medialization surgery, guided by individualized consideration of vocal fold position and surface pliability, can improve phonatory outcomes.

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.

Failed medialization laryngoplasty: management by revision surgery

OBJECTIVE

The purpose of this study was to evaluate the cause of immediate and late medialization laryngoplasty failures and to describe their management.

METHODS

A retrospective analysis was performed in 20 patients who underwent revision surgery after failed medialization laryngoplasty. Analysis was based on preoperative spiral CT scan, preoperative and postoperative videostrobolaryngoscopy, and phonatory function measures.

RESULTS

Three major types of failures were identified. The most common problem was arytenoid rotation with a persistent posterior glottic gap (11 of 20). Malposition or wrong size of the implants resulted in a lateralized vocal fold or false vocal fold medialization (6 of 20). Three patients had implants that were extruding. Late atrophy and bowing resulted in a glottal gap (2 of 20). One patient had fibrosis around the implant requiring removal. Spiral CT scan of the larynx located the implant precisely and showed the degree of arytenoid rotation. Patients with arytenoid rotation and posterior gap had revision medialization combined with arytenoid adduction. Revision medialization was performed in 11 patients, arytenoid adduction in 12 patients, lipoinjection in 2 patients, and 4 implants were removed. The voice was improved in 15 patients. Improved voice was correlated with improved phonation time and reduced phonatory airflow rates.

CONCLUSION

Immediate and late failures of medialization laryngoplasty are due to several possible causes. Revision surgery is feasible and highly successful. To select between the surgical alternatives work up should include preoperative analysis of vocal function, videostrobolaryngoscopic analysis, and spiral CT of the larynx.

Fascia Augmentation of the Vocal Fold: Graft Yield in the Canine and Preliminary Clinical Experience

INTRODUCTION

Glottal insufficiency resulting from vocal fold bowing, hypomobility, or scar is frequently treated by injection augmentation. Injection augmentation with fat, collagen, gel foam, polytef, and recently, fascia lata has been previously reported. Variable graft yield and poor host-tissue tolerance have motivated the continued search for an ideal graft substance.

STUDY DESIGN

A prospective trial of autologous fascia augmentation of the vocal cord in the human and in an animal model.

METHODS

Autologous fascia injection augmentation (AFIA) was evaluated in 8 canines and 40 patients at our institution between 1998 and 2000. The animal study compared graft yield from AFIA with autologous fat yield. The outcome measure was graft yield calculated from histological examination of larynges 12 weeks after injection augmentation. Clinical trial outcome measures included symptom surveys, acoustical voice analyses, and subjective voice assessments. Mean follow-up was 9 months.

RESULTS

In the canine larynx, the mean graft yield for AFIA was 33% (range, 5%-84%) compared with autologous lipoinjection (47%; range, 7%-96%; P =.57). Subjective improvement in vocal quality was reported by 95% of patients (38 of 40) after AFIA. Preoperative and postoperative voice analysis data were obtained from 26 patients. Subjective voice rating demonstrated a significant improvement after AFIA (P <.0001). Acoustical parameters of jitter, shimmer, noise-to-harmonic ratio, phonatory range, and degree unvoiced improved significantly (P <.05) in all patients after fascia augmentation.

CONCLUSIONS

Based on the animal study, we concluded that graft yields are excellent but variable for AFIA. The result is similar in variability and overall yield to autologous lipoinjection. Subjective and objective analyses of voice outcomes after AFIA are universally improved. Fascia appears to be an excellent alternative to lipoinjection in properly selected cases of glottic insufficiency.

Advances and refinements in phonosurgery

Scientific discovery, technological advances, and improved outcomes assessment have resulted in advances and refinements in phonosurgery. Three areas of substantial evolution are phonomicrosurgery, laryngeal framework surgery, and the use of implantable materials in vocal folds. Discovery of the importance of the superficial layers of the lamina propria has led to increased use of more limited medial microflap approaches and less frequent use of the classic lateral cordotomy flap approach. Alternative approaches to managing vocal fold scarring defects have addressed the separation of body and cover and provided suitable lamina propria replacement. Approaches to sulcus vocalis have been refined to address type II (linear vergeture) and type III (focal invasive pit) sulcus, where there is loss of lamina propria, while still recognizing the common nonpathological type I (physiological) sulcus. Technological advancements such as photodynamic therapy, tuned dye lasers, and laryngeal microdebridement have augmented the armamentarium for mechanical removal of laryngeal papillomata. Careful infusion-assisted microexcision and adjunctive medical management have been refined and made more effective. Laryngeal framework surgery has embraced the development of Silastic, hydroxylapatite, expanded polytetrafluoroethylene, and titanium shims. Anatomical studies have helped to improve operative precision and safety, and have led to inventive variations in arytenoid repositioning that improve closure of the posterior subunit. Vocal fold augmentation by injection has been facilitated by innovative use of the rigid telescope and intraoperative videostroboscopy. Anatomical studies have focused on the infrafold region and rheological studies have attempted to match viscoelastic properties of injectable substances to those of vocal fold tissues. Alloplastic materials such as Teflon have been largely supplanted by newer bioimplantables such as fat, collagen, and fascia.

Histologic findings of silastic medialization in the canine model

OBJECTIVES

Examine the long-term histological effects of Silastic medialization using a canine model.

STUDY DESIGN

Prospective study evaluating the effects of Silastic medialization in six canine larynges.

METHODS

Two subject groups were evaluated. The first group of four dogs underwent recurrent laryngeal section followed by Silastic medialization on the paralyzed side and placement of a smaller implant on the mobile side. Two of the dogs were sacrificed at 9 months and two at 2 years. The second subject group consisted of two additional dogs who underwent Silastic medialization followed by removal of the implants at 7 months and were sacrificed 18 months later. The larynges were then processed, sectioned in the axial plane, and examined microscopically.

RESULTS

Histological findings of both the mobile and paralyzed sides showed a thin (< 0.5 mm) fibrous capsule surrounding the implant and minimal inflammatory response. Vocal fold mobility was maintained in all cases in which the recurrent laryngeal nerve was left intact. Capsule formation and inflammatory response were similar in all cases.

CONCLUSIONS

Minimal tissue reactivity over a prolonged period of time suggests that long-term results of Silastic medialization remain stable in paralyzed and mobile vocal folds for up to 2 years. Similar tissue response in the subjects in which the Silastic block was removed also suggests that Silastic medialization is a reversible procedure.