Textured polydimethylsiloxane elastomers in the human larynx: safety and efficiency of use

Complications of Polydimethylsiloxane for Injection Laryngoplasty: Retrospective Case Series of 10 Patients Requiring Explant and Literature Review

Polydimethylsiloxane (PDMS) has been reported in the literature as a safe and permanent material for injection laryngoplasty (IL)1 We present a case series of 10 patients who had undergone PDMS-IL at external campuses which resulted in unsatisfactory voice outcomes and were managed with explant. A literature review on PDMS-IL associated complications is presented. In our series, seven out of ten patients (70%) with voice outcomes data, developed an improved voice post PDMS explant. Seven out of ten patients (70%) had improved vocal fold pliability with two patients (20%) having irretrievably damaged pliability due to the PDMS disturbing the superficial lamina propria. All eight patients with specimens submitted for histopathology had foreign body inflammation reported. There were ten additional cases reported in the literature with post PDMS adverse outcomes managed with explant. In the literature, explant improved the voice in seven out of nine patients (78%) with reported voice outcomes and partially restored vocal fold pliability in five out of six patients (83%) which commented on this outcome. PDMS-IL carries a risk of irreversible loss of vocal fold pliability which should be informed to the patient as part of the preoperative informed consent.

Preclinical testing of an anal bulking agent coated with a zwitterionic polymer in a fecal incontinence rat model

Fecal incontinence is a disabling condition in which the passage of fecal material cannot be controlled. Although the condition is not life-threatening, it can seriously reduce the quality of life...

Injectable polydimethylsiloxane microfiller coated with zwitterionic polymer for enhanced biocompatibility

Silicone-based fillers have been applied in several branches of medicine, such as soft tissue augmentation, because of their stability and durability. However, the inherently hydrophobic surfaces of silicone occasionally cause excessive deposition of the fibrous matrix in vivo, leading to severe fibrosis. In this study, we evaluated the use of a zwitterionic copolymer to offer a facile surface treatment method for silicone-based fillers and performed a preclinical trial of the formulation as-prepared. The copolymer has amphiphilic moieties, which act as macromolecular surfactants that can functionalize and stabilize the silicone particles during fabrication. The effectiveness and safety of the particle filler were evaluated histologically by scoring the peri-implant tissues into previously defined categories. Our results suggest that zwitterion-coated silicone fillers can inhibit protein adsorption, and thus, help attenuate foreign body reactions in a rat model. This demonstrates their potential for wide application in different fields within the discipline of medicine.

Long-term outcomes of basic fibroblast growth factor treatments in patients with vocal fold scarring, aged vocal fold, and sulcus vocalis

OBJECTIVE

Fibrotic changes in the vocal fold mucosa have been observed in patients with vocal fold scarring, aged vocal fold, and sulcus vocalis, which often lead to severe voice disorders. Previous research suggests that the basic fibroblast growth factor (b FGF) improves variations in vocal fold properties [1,2]. Although clinical studies on b FGF treatments have been conducted [3,4,5], these studies only demonstrated the efficacy of this drug over a short period. The present study is the first to investigate the long-term efficacy of b FGF treatment.

METHODS

b FGF injections were performed in six patients from January of 2016 to December of 2017 at our institution. Patient follow-up continued for at least two years after the last injection. Three patients had vocal fold scarring, two had aged vocal fold atrophy, and one patient had sulcus vocalis. Each vocal fold was injected with 10 µg of b FGF four times. Voice and stroboscopic examinations were performed after surgery (at one month, three months, six months, one year, two years). Fundamental frequency, maximum phonation time (MPT), mean flow rate (MFR), amplitude perturbation quotient (APQ), pitch perturbation quotient (PPQ), and noise-to-harmonic ratio (NHR), and voice handicap index-10 (VHI-10) were examined and compared statistically between the pretreatment time and at each posttreatment time point.

RESULTS

The speaking F0 had an obvious decreasing tendency, with significant differences suggesting the increase in volume in the vocal folds. Aerodynamic parameters also showed small improvements. The most remarkable improvement was observed in the acoustic parameters, indicating that the treatment could improve the vocal fold to make vibrations symmetrically and regularly for a long period. Achievement of symmetry and regularity on vocal fold vibrations suggested the property changes had happened in the vocal folds. Consequently, the score of VHI-10 had improved, indicating high patient satisfaction with this treatment.

CONCLUSION

b FGF injections could be a reliable treatment option for diseases that deteriorate the property of vocal fold.

Transoral laser microsurgery for polydimethylsiloxane (VOX Implant®) explantation

INTRODUCTION

Polydimethylsiloxane (VOX Implant®) injection into the larynx is a surgical technique used to restore volume to paralysed or atrophic vocal folds. We present a case series that demonstrates the feasibility of explantation of this non-resorbable material in the event of complications secondary to this injection.

DESCRIPTION

We report four cases of VOX Implant® explantation. In every case, explantation was performed following complications such as dysphonia and/or dyspnoea secondary to injection of this material. VOX Implant® explantation was performed via cordotomy using transoral lasermicrosurgical techniques.

DISCUSSION

VOX Implant® explantation improved voice and breathing parameters in all patients. Explantation can be performed by transoral microsurgery in the presence of complications related to polydimethylsiloxane injection.

3D Microstructured Scaffolds to Support Photoreceptor Polarization and Maturation

Blinding disorders of the outer retina involve dysfunction and degeneration of photoreceptors. One potential approach to treat these forms of blindness is to repopulate the outer retina via a simple bolus injection of donor photoreceptors. However, this may not be ideal due to the highly polarized organization of photoreceptors that include apical light sensing photopigments and basal axon terminals. Furthermore, bolus injections create uncertainty with regard to the area, density, and retention of donor cells. Here, a novel and robust microfabrication process is developed to create 3D, micrometer-sized complex structures in ultrathin and biocompatible elastomer films (nonbiodegradable polydimethylsiloxane and biodegradable poly(glycerol-sebacate)) that can serve as polarizable photoreceptor delivery scaffolds, consisting of an array of cup-shaped photoreceptor capture wells that funnel into a microchannel. This "wine glass" scaffold design promotes efficient capture of human pluripotent stem-cell-derived photoreceptor cell bodies and guidance of basal axon extensions, ultimately achieving a uniform level of organization and polarization that is not possible with bolus injections or previously described scaffolds. In addition to future therapeutic applications, our scaffold design and materials provide a platform to generate reproducible and scalable in vitro models of photoreceptor-based diseases.

Polydimethylsiloxane Injection Laryngoplasty for Unilateral Vocal Fold Paralysis: Long-Term Results

OBJECTIVES

To analyze the long-term objective, perceptive, and subjective outcomes after endoscopic polydimethylsiloxane (PDMS) injection laryngoplasty in unilateral vocal fold paralysis.

STUDY DESIGN

A retrospective study carried out between January 2008 and January 2012.

SETTING

Head and Neck Department, University Hospital of Modena, Modena, Italy.

METHODS

This was a retrospective analysis of 26 patients with unilateral vocal fold paralysis who underwent endoscopic injection of PDMS under general anesthesia. A voice evaluation protocol was performed for all patients, which included videolaryngostroboscopy, maximum phonation time, fundamental frequency, analysis of the harmonic structure of the vowel /a/ and the word /aiuole/, Grade of Dysphonia, Instability, Roughness, Breathiness, Asthenia, and Strain scale, and Voice Handicap Index. The protocol was performed before surgery, in the immediate postoperative period, and at least 3 years after surgery. The mean follow-up period was 73 months (range 39-119 months).

RESULTS

The statistical analysis showed a significant improvement (P < 0.01) for all of the objective, perceptive, and subjective parameters by comparison between the preoperative and long-term follow-up data; moreover, no statistically significant difference was found between the postoperative and long-term follow-up data. This indicates that injection laryngoplasty with PDMS guarantees long-lasting effects over time. No complications were reported in our series.

CONCLUSION

Injection laryngoplasty with PDMS can be considered to be a minimally invasive and safe technique for the treatment of unilateral vocal fold paralysis. Moreover, it allows very good and stable results to be obtained over time, avoiding repeated treatments and improving the quality of life of the patients.

Injectable Aorta Tissue Paste for Vocal Fold Medialization: Residence Time, Biocompatibility, and Comparison to Predicates in a Guinea Pig Subdermal Model

OBJECTIVES

Aortic homografts integrate well with laryngeal tissue when used in reconstructive surgery. It was hypothesized that a paste of aortic homograft, rich in slow-to-degrade elastin, would compare favorably in residence time and biocompatibility to predicate materials used for vocal fold injection-medialization.

METHODS

An injectable aorta paste (AP) was made by pulverizing aortic homografts at -196°C (cryomilling). To assess residence time and biocompatibility, 0.3 cc was injected subdermally in guinea pigs (n = 3 per 2-, 4-, 8-, 16-, 24-week time points) followed by histological analysis. To test particle size versus residence time, APs made using 80 or 200 seconds of cryomilling were compared. Implant characteristics of AP were then compared to Restylane, Radiesse Voice (Hydroxylapatite), Radiesse Voice Gel, and Cymetra in additional animals (n = 6 per 4-, 8-, 12-week time points).

RESULTS

Injected AP formed ovoid masses with minimal inflammation. Cellular infiltration was mild and increased with survival time. There was a gradual reduction of implant volume to ~40% at 24 weeks. Increased residence time for paste with larger particles (80 cryomilling seconds) was noted. Von Kossa staining showed progressive calcification of the AP. Cymetra was difficult to reconstitute reliably but formed subdermal masses similar to AP in shape, size, and reactivity and without calcification. The other predicates showed good biocompatibility but spread more widely and erratically in the tissue.

CONCLUSION

Aortic paste is easy to create, biocompatible, degrades slowly, and forms well-defined implants in guinea pig subdermal tissue. The AP implants calcified over time, and experiments are ongoing to determine the source of calcification and how it might be controlled or exploited clinically.

Polydimethylsiloxane Particles for Permanent Injection Laryngoplasty

Objectives:

Polydimethylsiloxane (PDMS) particles are a nonresorbable material that allows for permanent vocal fold augmentation. This study investigated morbidity and voice quality in patients treated for unilateral vocal fold paralysis by injection of PDMS particles.

Methods:

Fourteen patients who had neurogenic unilateral vocal fold paralysis of different causes were included in this prospective study. Each patient underwent videostroboscopic assessment before and after operation. Friedrich's dysphonia index (DI), a score system combining subjective and objective parameters, was used to describe voice quality. A DI of 0 reflects a normal voice, and a DI of 3 stands for complete aphonia. The PDMS particles were injected into the paraglottic space by microlaryngoscopy under general anesthesia.

Results:

The median follow-up was 4.1 months. There was no complication attributable to the injection of PDMS particles. The mean DI was 2.8 before operation. After the operation, voice quality improved significantly in each patient, as reflected by a mean postinjection DI of 1.4.

Conclusions:

Particles of PDMS provide a relatively safe and minimally invasive option for permanent vocal fold augmentation. The functional results in terms of voice improvement are comparable to those obtained with other techniques, including thyroplasty. In the European Community, PDMS particles are officially approved for use in the human larynx.

Particulate Silicone for Vocal Fold Augmentation: Morphometric Evaluation in a Rabbit Model

To study the augmentation of the paralyzed vocal fold in response to the injection of particulate plastics in a rabbit model, we performed a prospective, experimental, and controlled study in 45 New Zealand rabbits with surgical vocal fold paralysis. We compared a control group (acute unilateral recurrent nerve section) with a group that underwent polytetrafluoroethylene (PTFE) injection and with another group that underwent polydimethylsiloxane (PDMS) injection. Equal volumes of implant material were injected. The animals were killed either 6 weeks or 6 months after intervention and compared by histomorphology using a digital measuring system. The injection sites showed a substantial foreign body giant cell reaction against the PDMS and PTFE, surrounded by a light, fibrous stroma. No differences in the frequency of displacement or disaggregation of implants were observed. No extrusion to the laryngeal lumen, signs of migration outside the larynx, or malignant changes were seen. No differences were found in the length of the vocal fold between the PDMS group and the PTFE group. The vocal fold was thicker in the PDMS group than in the PTFE group, but a statistically significant difference was found only for the anterior and middle thirds at 6 weeks. In the PDMS sample, the thicknesses were similar in the 6-week and 6-month subgroups. The group with injection of PDMS yielded histologic images compatible with greater and more stable medialization than did the group with injection of PTFE.

Type I Thyroplasty in Previously Irradiated Patients

Objectives

(1) Review and report our experience performing medialization thyroplasty (MT) in previously irradiated patients and (2) compare complications and voice outcomes in 2 cohorts (irradiated vs nonradiated) to evaluate safety and efficacy.

Study Design

Case series with chart review.

Setting

Academic medical center.

Subjects

All patients (44 total) who underwent MT from 2011 to 2015.

Methods

Demographic data, complications, and acoustic and subjective voice outcome parameters were collected. The complication rates and voice outcome results were compared between 2 cohorts: patients with a history of radiation to the neck versus those with no radiation history.

Results

There were 7 previously irradiated patients and 37 nonradiated patients, with median follow-up of 314 and 538 days, respectively. One complication was noted in each group, and this complication rate was not significantly different ( P = .26). Both cohorts demonstrated significant postoperative improvement in subjective voice assessment ( P = .04, P < .0001) as well as maximum phonation time ( P = .02, .001) when compared with preoperative data.

Conclusions

Our study suggests that MT can be safely and effectively performed in irradiated patients. We found no statistically significant difference in the safety of performing MT in irradiated versus nonradiated patients, and there was significant improvement in subjective voice parameters and maximum phonation time in both groups. A larger prospective study is required to statistically determine whether the significant improvements in objective parameters seen in the nonradiated group are present in irradiated patients as well.

[Glottis injection to improve voice function : Review of more than 500 operations]

BACKGROUND

Hoarseness due to insufficient glottal closure can be treated by injection laryngoplasty (augmentation). Vocal fold injections can be performed as an in-office procedure or under general anesthesia. As injection materials have recently improved and different injection approaches are available, injection laryngoplasties are performed much more frequently.

OBJECTIVES

Advantages and disadvantages of injection materials, laryngeal approaches, and differential indications are described.

MATERIALS AND METHODS

Literature research and experience of more than 500 laryngeal injection procedures are provided.

RESULTS AND CONCLUSIONS

Sophisticated use of available injection materials can provide a satisfying improvement of voice function with minimal patient discomfort. Adequate indication is mandatory for a favorable outcome. Further improvement regarding biocompatibility and the duration of injection materials is desirable.

The anisotropic nature of the human vocal fold: an ex vivo study

The purpose of this study was to measure the relationship between the shear elastic properties of vocal fold with respect to the direction of applied stress. There is extensive published material that quantifies the shear viscoelastic properties of the vocal fold, but as much of these data were obtained using rotating parallel plate rheometers, which are unable to resolve out difference of the shear elastic behaviour with respect to direction, there is very little data that indicates anisotropic behaviour. To overcome this gap in knowledge, the team devised an apparatus that is capable of applying a shear stress in a known direction. A series of measurements were taken at the mid-membranous position, in the transverse and longitudinal directions. Point-specific measurements were performed using fourteen human cadaver excised larynges, which were hemi-sectioned to expose the vocal fold. An extremely low sinusoidal shear force of 1 g was applied tangentially to the membrane surface in both the longitudinal and transverse direction, and the resultant shear strain was measured. With the probe applied to the intact vocal fold, the average ratio of the elasticity in the transverse with respect to the longitudinal direction was 0.55. Further investigation using histological staining of collagens in the lamina propria indicates that there is a visible difference in the general alignment of collagen fibres when comparing the coronal and the sagittal sections. Our conclusion is that there is a quantifiable difference between the shear elastic response of the lamina propria in the longitudinal and transverse directions, and that this could be explained by the difference in alignment of collagen fibres within the lamina propria.

Influence of Different Growth Factors on Chondrogenic Differentiation of Adipose-Derived Stem Cells in Polyurethane-Fibrin Composites

Introduction

Chondrogenic differentiation of adipose-derived stem cells (ASCs) has proven to be feasible. To compensate for laryngeal palsy or cartilage defects after surgery or trauma using tissue engineering, a formable and stable scaffold material is mandatory.

Methods

ASCs were seeded in fibrin-polyurethane scaffolds and cultured in chondrogenic differentiation medium adding the growth factors TGF-□1, TGF-□3, and BMP-2 for up to 35 days.

Results

Histological examination showed acid glycosaminoglycans in the extracellular matrix in all groups. Immunofluorescence presented positive staining for collagen II, aggrecan, and SOX-9 in the TGF-□1–, TGF-□3–, and BMP-2-group. With Real-time PCR analyses, chondrogenic differentiation became apparent by the expression of the specific genes COL2A1 (collagen II), AGC 1 (aggrecan), and SOX-9, whereas collagen II expression was low in all groups compared to bone marrow-derived stem cells (BMSC) due to reduced chondrogenic ability.

Conclusions

These findings demonstrate the general ability of ASCs to differentiate into matrix-producing chondrocytes in fibrin-polyurethane scaffolds. However, further experiments are necessary to enhance this chondrogenic potential of ASCs seeded in fibrin-polyurethane scaffolds in order to produce a suitable regeneration method for treating cartilage defects or an implantable medialization material for vocal cord palsy.

Larynx: implants and stents

In the human larynx, implants a primarily used for the correction of glottis insufficiency. In a broader sense laryngeal stents may be considered as implants as well. Laryngeal implants can be differentiated into injectable and solid. The most important representatives of both groups are discussed in detail along with the respective technique of application. Laryngeal stents are primarily used perioperatively. Different types and their use are presented.

Vocal fold injection: review of indications, techniques, and materials for augmentation

Vocal fold injection is a procedure that has over a 100 year history but was rarely done as short as 20 years ago. A renaissance has occurred with respect to vocal fold injection due to new technologies (visualization and materials) and new injection approaches. Awake, un-sedated vocal fold injection offers many distinct advantages for the treatment of glottal insufficiency (vocal fold paralysis, vocal fold paresis, vocal fold atrophy and vocal fold scar). A review of materials available and different vocal fold injection approaches is performed. A comparison of vocal fold injection to laryngeal framework surgery is also undertaken. With proper patient and material selection, vocal fold injection now plays a major role in the treatment of many patients with dysphonia.

MR evaluation of PDMS injections in head and neck tissues: a pilot study

OBJECTIVES

To describe the magnetic resonance (MR) appearance of polydimethylsiloxane (PDMS) injections in the head and neck region.

STUDY DESIGN

Retrospective review of MR images from a case series.

METHODS

MR images of 10 patients, who underwent PDMS injections at our department, were reviewed. Data from imaging were collected and analyzed.

RESULTS

After injection, PDMS can be identified in MR images, particularly in T2-weighted images in the early stages. Its MR characteristics are similar to silicone in other regions, but with time, its appearance can change.

CONCLUSIONS

The integration of PDMS with tissues may also be reflected in changes in MR appearance, as a result of an increased amount of fibrous tissue in the region injected. Radiologists and ENT specialists may benefit from knowledge of the MR characteristics and variability in appearance of PDMS in human tissues for improving image interpretation.

Quality of life in patients treated with PDMS injection for swallowing disorders

Objective: To document the efficacy of polydimethylsiloxane (PDMS) injections in patients with swallowing disorders after partial supracricoid laryngectomy; to assess the importance of quality-of-life (QOL) outcome in oncologic patients.

Subjects and Methods: The study included 11 patients with swallowing disorders after partial laryngectomy and appropriate rehabilitation. They were treated with endoscopic injection of PDMS; QOL was investigated with four questionnaires (M.D. Anderson Dysphagia Inventory, Performance Status Scale for Head and Neck Cancer, Performance Karnofsky Scale, and Voice Handicap Index-10) before and after surgical treatment and further rehabilitation.

Results: A significant improvement in QOL of all 11 patients was seen after endoscopic injection. The impact of this treatment on the social life of patients was considerable.

Conclusion: Swallowing disorders and speech problems are quite common complications of partial laryngectomy. QOL in oncologic patients is a mandatory outcome measure. PDMS injection showed an improvement in the everyday life of selected patients.

[Surgical voice rehabilitation in unilateral vocal fold paralysis]

Unilateral recurrent nerve paralysis leads to glottic insufficiency, significantly reducing vocal ability. Due to its unusually long course, the recurrent laryngeal nerve is prone to iatrogenic lesions involves many medical fields generally with little expertise in voice disorders. Whenever the etiology is uncertain, a complete diagnostic work-up is mandatory. Indirect laryngoscopy confirms the diagnosis. Laryngeal electromyography is of great value because it differentiates between paralysis and ankylosis of the cricoarytenoid joint. Moreover in many cases laryngeal electromyography yields a reliable prognosis of clinical outcome. While unfavorable results can be predicted with high accuracy, correct prognosis of complete recovery is more difficult. Speech therapy is the treatment of choice in cases of unilateral recurrent nerve palsy. Patients with persistent glottal gap may express the wish for surgical voice rehabilitation. Nowadays a broad spectrum of endoscopic and open approaches are available for this purpose. This review describes advanced techniques of voice-improving surgery available in specialized centers today.

Therapy of unilateral vocal fold paralysis with polydimethylsiloxane injection laryngoplasty: our experience

The objective of this study was to document functional results and to compare objective and subjective voice measures after endoscopic laryngoplasty with injection of polydimethylsiloxane (PDMS) for the treatment of unilateral vocal fold paralysis, and to verify PDMS biocompatibility in vocal fold. The design used was a longitudinal prospective study. Fifteen patients with unilateral vocal fold paralysis underwent endoscopic injection of PDMS in general anesthesia. Accurate voice evaluation protocol (acoustic and aerodynamics analyses, GIRBAS [Grade, Instability, Roughness, Breathiness, Asthenia, and Strain] scale, videostrobolaryngoscopy, and Voice Handicap Index test) before, after surgery, and at follow-up time was performed. The median follow-up was 21.7 months (range, 6-35). Data obtained were statistically significant. All acoustic, aerodynamics, perceptive, and subjective evaluations showed a significant improvement. No complications due to PDMS were reported. Functional results were found comparable to framework surgery. Endoscopic injection laryngoplasty with PDMS is a safe and long-term option for treatment of unilateral vocal fold paralysis.

Phonosurgery after endoscopic cordectomies. II. Delayed medialization techniques for major glottic incompetence after total and extended resections

Major glottic incompetence is often encountered after total (Type IV) and extended (Type V) cordectomies and is responsible for poor vocal outcome. Even though the vast majority of patients do not complain of significant limitations in daily life, a selected number of them eventually require some sort of phonosurgical treatment in order to improve voice quality. Different techniques have been described in the literature to ameliorate long-term vocal outcome. The aim of the present report was to retrospectively describe our experience in this challenging clinical scenario. Between April 1999 and March 2005, 24 patients previously treated by Type IV-V endoscopic cordectomies for T1 and T2 glottic cancer presented unsatisfactory vocal outcome in spite of intensive speech therapy and therefore underwent some form of phonosurgical treatment at our Department after at least 12 months without evidence of local-regional recurrence. Patients were treated by medialization thyroplasty with a Montgomery System Implant (two cases), Gore-Tex strips (16 cases), medialization thyroplasty with Gore-Tex associated with anterior commissure laryngoplasty (three cases), and augmentation with Vox Implant injection (three cases). Nineteen patients had comprehensive evaluation by videolaryngoscopic examination and subjective, perceptual, and objective voice analysis both in the pre-phonosurgical treatment period and after at least 12 months. Comparison of pre- and postoperative videolaryngoscopic findings revealed improved glottic closure in 74% of patients. Comparison between the pre- and postoperative subjective, perceptual, and objective voice analysis by the Wilcoxon matched-pair test showed a statistically significant improvement from a Voice Handicap Index mean value of 46 (preoperative) to 21 (postoperative); an improvement for each parameter of the GRBAS scale with statistically significant differences for G, B, A, and S, while R showed only an improving trend; and statistically significant improvement in the mean values of Jitter, Shimmer, Noise to Harmonic Ratio, and Maximum Phonation Time. In conclusion, the different delayed phonosurgical procedures herein used demonstrate the possibility to improve vocal outcomes after total and extended cordectomies in selected and highly motivated patients that have not achieved satisfactory performance after prolonged and intensive speech therapy.

Voice quality improvement after management of unilateral vocal cord paralysis with different techniques

The aim of this study was to objectively evaluate the voices of patients suffering from unilateral vocal cord paralysis, before and after endoscopic augmentation and thyroplasty. In the past, we used injectable Teflon to treat this condition; later techniques included collagen injection and Isshiki thyroplasty. In the last 7 years, preferred treatment methods have included Bioplastique injection and lipoaugmentation of the vocal cords as well as medialization thyroplasty using a titanium implant according to Friedrich. Pre- and postoperative data was evaluated and compared to 25 patients. Appropriate glottic closure of the vocal cords was achieved in every case, in most cases after the first intervention. We used voice range profile measurements to evaluate the results. An objective evaluation was performed using the Friedrich dysphonia index. Significant improvements were found: the dysphonia index decreased in every case, from an average of 2.47, preoperatively, to an average of 1.18 postoperatively. In agreement with earlier studies, voice pitch range was the only parameter that not significantly improved. There was no statistical difference between the lipoaugmentation and thyroplasty according to Friedrich. We concluded that both endoscopic methods and thyroplasty can be used to achieve an optimal result. Cases must be evaluated individually so that the best technique, or combination of methods can be determined.

[Therapy for unilateral vocal fold palsy]

The main symptom of unilateral vocal fold palsy is hoarseness, which can cause considerable disturbance to the patient depending on its extent and the patient's individual situation. Therapy aims at the restitution of a tuneful and resilient voice, which can be achieved by surgical or conservative means, improving the glottal closure and synchronizing the vocal fold vibrations during phonation. Vocal therapy is a common conservative method that may be supported by psychotherapeutic or physical procedures. In surgical therapy, there is a distinction between techniques of endoscopic augmentation by injecting different materials into the vocal folds and transcutaneous laryngeal framework surgery, i.e., transferring the paralyzed vocal fold to the glottal midline. Particularly apt for injection are biocompatible materials amount and position whose can easily be controlled. However, the inevitable resorption of many materials causes deterioration in voice quality. Furthermore, the change of vocal fold morphology obstructs regular phonatory vibration. On the other hand, medialization thyroplasty leads to permanent voice amelioration without a substantial complication rate when performed by experienced surgeons.

Treatment of vocal fold immobility by injectable homologous collagen: short-term results

Various implant materials have been used to treat glottic insufficiency by means of intracordal injection. So far, autologous fat is the most commonly used. Homologous collagen is a new injectable acellular graft material. This collagen, made of 200-mu particles, is delivered as a freeze-dried powder in a 1-cc-unit syringe and is rehydrated with standard saline solution prior to injection. A prospective study was conducted on 23 patients with unilateral vocal fold paralysis. All injections were performed under general anesthesia using the collagen injection system and a 25-gauge needle. A mean quantity of 1.05 ml (SD: 0.41) of collagen was injected as much as possible in the deep part of the lamina propria. Voicing was resumed after 2 days. The mean follow-up was of 8 months (range: 2-18). Functional results were measured according to the ELS protocol. G(rade), R(oughness) and B(reathiness) according to Hirano were reported on a four-point grading scale showing an improvement from 2.13 to 1.13 for G (P<0.001), from 1.50 to 0.82 for R (P<0.002) and from 1.73 to 1.05 for B (P<0.001). The parameters selected for videolaryngostroboscopy, G(lottal) (Clo)sure, (R)egularity, (M)ucosal (W)ave and (Sym)metry, were measured on a visual analog scale. They showed an improvement from 23 to 19 for Clo (P=0.087), from 15 to 6 for R (P=0.001), from 15 to 11 for MW (P=0.039) and from 17 to 8 for Sym (P=0.001). For the aerodynamic parameters, the maximum phonation time (MPT) and the phonation quotient (PQ) showed an improvement from 5.8 to 8.9 s (P=0.002) and from 704.5 to 449.7 ml/s (P=0.004), respectively. The acoustic parameters were improved from 5.3 to 3.6 (P=0.045) for the jitter (%), they didn't change for the shimmer [(%): 2.4], and they were improved non-significantly from 187.9 to 218.7 Hg for the frequency range. The lowest level intensity was non-significantly increased from 49.6 to 51.3 dB. Regarding the subjective evaluation, the Voice Handicap Index (VHI) was improved from 65 to 37. To date, no homologous collagen-related morbidity has been observed. Injectable homologous collagen appears to be safe and suitable for injection laryngoplasty. Long-term results are pending.

Treatment of dysphagia and dysphonia following skull base surgery

This article provides an overview of considerations in the evaluation and treatment of lower cranial nerve deficits, specifically in cranial nerves IX, X, and XII, in the context of skull base tumors and their treatment.

Therapy of periprosthetical leakage with tissue augmentation using Bioplastique around the implanted voice prosthesis

Having a voice prosthesis provides a good possibility for speech rehabilitation after total laryngectomy has been performed, especially if common complications such as leakage around the valve can be reduced effectively. The early applications of a voice prosthesis-which was originally invented and applied by Mozolewski in 1972, was further developed by Blom and Singer and became an internationally available implantable instrument by 1980- already made clear not only the typical benefits, but also the complications, such as possible leakage around the implanted valve. Remacle proposed the injection of collagen into the surrounding tissues in order to stop leakage. Knowing that collagen is usually resorbed as time goes by, new substances that can be tolerated by human tissues must be found. This article reports the experiences of the authors in the search for such an injectable material that cannot be resorbed and does not migrate. In order to solve the above-mentioned problem, Lichtenberger introduced the injection of Bioplastique into the perivalvular tissues. This delivered the best results ever achieved in this field at our department. During the past 2 years, Bioplastique augmentation was performed for seven laryngectomized and speech-rehabilitated patients in order to reduce periprosthetical leakage. All procedures were successful in terms of either eliminating or reducing the leakage, and also the non-resorbable property of Bioplastique has been proven.

Injection laryngoplasty

After a nearly a century of development, augmentation of laryngeal tissue through injection remains as complex a procedure as it was in the earlier part of the century. Initially, the number of surgeons performing injection laryngoplasty was limited since the technique of injection was thought to be difficult and the selection of cases was thought to require the judgment of an accomplished laryngologist. Performing successful injection laryngoplasty does in fact require an understanding of laryngeal anatomy and physiology, and the physical characteristics of the substance to be injected. In addition, the surgeon must be aware of potential host reactions to the injected material. Finally, the surgeon must have an understanding of the etiology and configuration of the glottic insufficiency, and keep in mind the goals of the procedure.

Advances in the management of glottic insufficiency

PURPOSE OF REVIEW

Glottic insufficiency secondary to vocal fold scarring, atrophy, or paresis remains a clinically challenging problem for the laryngologist. Numerous methods have been described in the treatment of glottic insufficiency, belying the complexity of the problem. Type I thyroplasty and injection of fat, fascia, and gelatin powder have been the mainstay of treatment to date, but the ability to restore a normal mucosal waveform to a damaged vocal fold remains an elusive goal.

RECENT FINDINGS

Advances in the material and biomedical sciences have allowed the introduction of newer substances and techniques not only to medialize the vocal fold but also to help restore its viscoelastic properties as well. These substances include expanded polytetrafluoroethylene (ePTFE), collagen, cross-linked hyaluronic acid, micronized acellular human dermis calcium hydroxyapatite, and polydimethylsiloxane. ePTFE can be introduced through a window in the thyroid ala or placed intracordally, and the others can be injected either transorally or transcutaneously, allowing in-office placement under simple topical anesthesia.

SUMMARY

Although the ideal augmentation material and technique have yet to be devised, the laryngologist now has several options with which to address the problem of glottic insuffiency. Since the problem is complex and since it is possible that a customized solution may need to be devised on an individual basis, future laryngologists will need to be comfortable with the indications and applications that each material and technique will afford.

Bioplastique medialization therapy improves the quality of life in terminally ill patients with vocal cord palsy

Unilateral vocal cord palsy can result in a weak breathy voice and an inability to communicate effectively. This study was designed to assess prospectively the efficacy of polymethylsiloxane elastomer (Bioplastique) medialization injection therapy in patients with vocal cord palsy and terminal disease with particular regard to quality of life issues. Patients with unilateral vocal cord palsy secondary to malignant disease were offered Bioplastique injection. A digital voice recording was taken preoperatively and at 1 month, 3 months and 6 months postoperatively. Maximum phonation time (MPT) was recorded at the same intervals, and patients completed two questionnaires: the voice handicap index (VHI) and SF 36 general health questionnaire. Sixteen patients were entered into the study. There was a significant improvement in voice score, MPT, VHI and in three subgroups of the SF 36 at 1 month postoperatively, and the improvement was maintained in the small number who survived to 3 and 6 months. Bioplastique injection for unilateral vocal cord palsy produces a significant improvement in quality of life in addition to measured voice quality in patients with terminal disease. It should be recommended in patients even when the life expectancy is short.

Surgical voice rehabilitation after laser surgery for glottic carcinoma

Transoral laser surgery today is the mainstay of treatment for T1 and T2 glottic carcinoma. The vocal ability remains sufficient in the majority of patients. However, in some cases, a significant glottic gap may persist, leading to poor voice quality. We report a special technique of medialization thyroplasty using autologous cartilage specifically adapted for vocal rehabilitation after laser resection. Six patients with a significant glottic gap following laser surgery were treated. For vocal rehabilitation, a special medialization technique was performed. The superior rim of the thyroid cartilage of the resected side was exposed. A 1 x 2-cm piece of cartilage was harvested and reimplanted into a subperichondrial pouch created on the inner side of the thyroid cartilage. When phonation was optimal, this cartilaginous strut was sutured and/or glued in place. In all 6 cases, the vocal function improved significantly. The dysphonia index (0 = normal, 3 = aphonia), which includes objective parameters as well as expert voice ratings and the patient's perception, increased by 1.1 on average (range, 0.4 to 1.6). The results have been lasting. The established medialization techniques are of limited value in a larynx scarred by laser surgery. Injection augmentation is often futile because the tight scar tissue does not lend itself to augmentation. Implantation of nonorganic material may cause problems if revision surgery for tumor recurrence should become necessary or if the implant protrudes into the scarred endolarynx. The technique reported avoids these pitfalls and leads to voice quality improvement comparable to that of established medialization procedures.