Reversibility of medialization laryngoplasty. An experimental study

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.

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.

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.

Framework Surgery for Treatment of Unilateral Vocal Fold Paralysis

Laryngeal framework surgery is the current gold standard treatment for unilateral vocal fold paralysis. It provides a permanent solution to glottic insufficiency caused by injury to the recurrent laryngeal nerve. Various modifications to the original Isshiki type I laryngoplasty procedure have been described to improve voice and swallowing outcomes. The success of this procedure is highly dependent on the experience of the surgeon as it epitomizes the intersection of art and science in the field. The following article reviews the evidence, controversies, and complications related to laryngoplasty for unilateral vocal fold paralysis. It also provides a detailed analysis of how and when arytenoid-positioning procedures should be considered, and summarizes the literature on postoperative outcomes.

Polydimethylsiloxane versus polytetrafluoroethylene for vocal fold medialization: histologic evaluation in a rabbit model

The objective is to study the tissue reaction of the paralyzed vocal cord in response to the injection of particulate plastics in a rabbit model. Forty-five New Zealand rabbits with surgical vocal-fold paralysis were used in the study. Histologic reactions of the larynx and the regional lymph nodes were analyzed by a single blinded pathologist at 6 weeks and 6 months after a vocal-cord injection of Teflon or of silicone elastomer. Macroscopic studies of the liver, lungs, spleen, kidney, and brain were performed. The histological study showed a greater proportion of chronic granulomatous inflammation in animals injected with silicone than in those injected with Teflon. The immunohistochemical study showed a higher degree of phagocytosis of Teflon particles than of the silicone particles. The silicone group presented a more severe fibrous reaction than the Teflon group, but the difference was not significant. No migration particles were found. It is concluded that silicone, having a greater viscosity than Teflon because of the size of its particles, induces more fibrosis and a larger proportion of foreign giant cells in the host. Due to this histological reaction, silicone particles present greater anchorage and stability.

Improved outcomes with early vocal fold medialization for vocal fold paralysis after thoracic surgery

OBJECTIVE

To determine the clinical impact of early versus late surgical therapy for new onset unilateral vocal cord paralysis (UVCP) after thoracic surgery.

STUDY DESIGN

Patients diagnosed with new onset UVCP after esophagectomy, pneumonectomy or pulmonary lobectomy were reviewed to determine the incidence of pneumonia, need for postoperative bronchoscopy and length of stay (LOS). Comparisons were made between patients undergoing early (< or = 4 days after thoracic procedure) versus late rehabilitation (> or = 5 days after thoracic procedure) of their UVCP with vocal cord medialization.

RESULTS

Some 86 patients (27 esophagectomies, 43 pneumonectomies and 16 lobectomies) with new onset UVCP were examined. A total of 32 patients (37.2%) underwent early vocal cord medialization and 54 (62.8%) underwent late repair. The pneumonia rate for patients undergoing early vocal cord medialization (6.3%) was significantly lower than the rate for vocal cord medialization (37.0%, P=0.001, chi(2)). Early medialization patients required fewer postoperative bronchoscopies (mean number of bronchoscopies, 0.26) than late medialization patients (mean bronchoscopies, 0.94, P=0.013). The median LOS was significantly decreased for early versus late medialization patients in both pneumonectomy (reduction in LOS of 8 days) and lobectomy groups (reduction in LOS of 7 days).

CONCLUSIONS

Early vocal cord medialization decreases the pneumonia rate, the requirement for postoperative bronchoscopies and the LOS for patients suffering from new onset UVCP after thoracic surgery.

SIGNIFICANCE

Consideration should be given to early medialization for new onset UVCP when medically sound.

Laryngeal reinnervation with the hypoglossal nerve. I. Physiology, histochemistry, electromyography, and retrograde labeling in a canine model

This study was performed to determine whether the hypoglossal nerve (cranial nerve XI [XII]) would serve as a useful donor for laryngeal reinnervation by anastomosis to the recurrent laryngeal nerve (RLN). Twenty hemilarynges in 10 dogs were studied prospectively after XII-RLN anastomosis (group A; n = 5), split XII-RLN anastomosis (group B; n = 3), XII-RLN anastomosis with a 2-cm interposition graft (group C; n = 2), no treatment (group D; n = 5), RLN section (group E; n = 2), or ansa cervicalis-RLN anastomosis (group F; n = 3). Spontaneous activity was observed monthly by infraglottic examination through permanent tracheostomies and was recorded by electromyography. Laryngeal adductory pressure and induced phonation were obtained by stimulating the RLN while passing a pressure transducer balloon or humidified air through the glottis. At sacrifice, the laryngeal muscles were stained for adenosine triphosphatase to determine the ratio of type I to type II fibers. Retrograde labeling of the brain stem was performed with horseradish peroxidase. Infraglottic examination at 6 months showed a full range of adductory motion in groups A and B during the swallow reflex, comparable with that in group D. Groups C and F showed good bulk and tone, but little spontaneous motion. Group E remained paralyzed. Stimulation of the transferred nerves caused more activity in groups A and B than in the other groups; groups C and F partially adducted at high levels. The laryngeal adductory pressure responses of groups A and B were similar to those of group D. The XII-reinnervated larynges were capable of producing normal induced phonation. Retrograde labeling of the RLN showed that the reinnervating axons originated only in the hypoglossal nucleus. Electromyography of the reinnervated adductor muscles confirmed spontaneous activity in the dogs (awake). Histochemical analysis confirmed slow-to-fast transformation of both the posterior and lateral cricoarytenoid muscles, indicating that significant reinnervation occurred. We conclude that the hypoglossal nerve functions well as a donor for adductory reinnervation of the larynx.

Soft tissue response in the rabbit larynx following implantation of LactoSorb (PLA/PGA copolymer) prosthesis for medialization laryngoplasty

This project is designed to provide initial data regarding the use of polylactic acid/polyglycolic acid (PLA/PGA) copolymer ("LactoSorb" [Walter Lorenz Corp]), an alloplastic, resorbable material, as a prosthesis in an animal model of vocal fold medialization. Fifteen New Zealand white rabbits were utilized for left medialization laryngoplasty with LactoSorb implants after undergoing left recurrent laryngeal nerve section. At 1, 3, 6, and 9 months, the rabbits were sacrificed and their larynges were evaluated both grossly and histologically for tissue response to, and resorption characteristics of the implant, tissue cellularity, maintenance of vocal fold medialization, and airway patency. Additionally, 4 rabbits were used as controls, implanted with silicone rubber medialization implants, and sacrificed at 9 months for comparison. One rabbit underwent no surgery and was likewise used as a control. Grossly, no airway obstruction was noted, and no extrusions of the implants occurred. The LactoSorb implant maintained medialization in each group of sacrificed rabbits. Histologic findings revealed a very discrete, fibrous capsule around the implant in the 1- and 3-month rabbits, and the LactoSorb was still grossly visible. At 6 months, the thin fibrous capsule partially remained; at 9 months, the capsule was no longer evident, and the implant was no longer grossly visible. Endoscopic findings at the time of sacrifice in those rabbits implanted with silicone rubber included grossly patent airways with maintenance of medialization. In the rabbits implanted with silicone rubber, the histologic findings are similar to those described elsewhere. LactoSorb, because of its intermittent resorption rate, could offer an ideal alternative to currently utilized temporary, or resorbable, materials, and as such will hopefully prove an invaluable tool in the laryngologist's treatment planning and surgical repair of the patient with a paralyzed vocal fold.

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.