Stimmlippenaugmentation

Fibrin Gel Suspended Autologous Chondrocytes as Cell-based Material for long-term Injection Laryngoplasty

OBJECTIVES/HYPOTHESIS

Injection laryngoplasty of materials for unilateral vocal-fold paralysis has shown various results regarding the long-term stability of the injected material. We evaluated a fibrin-gel based cell suspension with autologous chondrocytes in-vitro and in-vivo as long-term-stable vocal-fold augmentation material in an animal model.

STUDY DESIGN

This study compises an in vitro cell-culture part as well as an in vivo animal study with New Zealand White Rabbits.

METHODS

In in-vitro experiments, auricular chondrocytes harvested from 24 New Zealand White Rabbits cadavers were cultivated in pellet cultures to evaluate cartilage formation for 4 weeks using long-term-stable fibrin gel as carrier. Injectability and injection volume for the laryngoplasty was determined in-vitro using harvested cadaveric larynxes. In-vivo 24 Rabbits were biopsied for elastic cartilage of the ear and autologous P1 cells were injected lateral of one vocal cord into the paraglottic space suspended in a long-term-stable fibrin gel. Histologic evaluation was performed after 2, 4, 12, and 24 weeks.

RESULTS

During 12-week pellet culture, we found extracellular matrix formation and weight-stable cartilage of mature appearance. In-vivo, mature cartilage was found in two larynxes (n = 6) at 4 weeks, in four (n = 6) at 12 weeks, and in five (n = 6) at 24 weeks mostly located in the paraglottic space and sometimes with spurs into the vocalis muscle. Surrounding tissue was often infiltrated with inflammatory cells. Material tended to dislocate through the cricothyroid space into the extraglottic surrounding tissue.

CONCLUSIONS

A cell-based approach with chondrocytes for permanent vocal-fold augmentation has not previously been reported. We have achieved the formation of structurally mature cartilage in the paraglottic space, but this is accompanied by difficulties with dislocated material, deformation of the augmentation, and inflammation.

LEVEL OF EVIDENCE

N/A Laryngoscope, 131:E1624-E1632, 2021.

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.

[Treatment of glottal gap]

Glottal gaps can be either physiological or pathological. The latter are multifactorial, predominantly organic in origin and occasionally functional. Organic causes include vocal fold paralysis or scarring, as well as a deficiency or excess of tissue. In addition to loss of the mucosal wave, the degree of hoarseness is primarily determined by the circumferential area of the glottal gap. It is thus important to quantify the extent of glottal insufficiency. Although a patient's symptoms form the basis for treatment decisions, these may be subjective and inadequately reflected by the results of auditory-perceptual evaluation, voice analysis and voice performance tests. The therapeutic approach should always combine phonosurgery with conventional voice therapy methods. Voice therapy utilises all the resources made available by the sphincter model of the aerodigestive tract and knowledge on the mechanism of voice production. The aim of phonosurgery is medialization, reconstruction or reinnervation by injection laryngoplasty or larynx framework surgery. These different methods can be combined and often applied directly after vocal fold surgery (primary reconstruction). In conclusion, the techniques described here can be effectively employed to compensate for glottal gaps.

A modified false vocal fold flap for functional reconstruction after frontolateral partial laryngectomy: a comparison with conventional open resection and laser cordectomy

OBJECTIVE

To describe a modified flap technique (MFT) involving the use of a false vocal fold flap for glottic reconstruction and the removal of arytenoid cartilage and to compare it with conventional frontolateral partial laryngectomy (FLPL) and laser cordectomy (LC).

METHODS

Twenty-eight MFT, 13 FLPL and 12 LC patients completed a standardised questionnaire for assessing aspiration, respiration, quality of life, and subjective voice quality. We analysed vocal function in terms of roughness, breathiness and hoarseness, measured voice range profiles, and performed videoendoscopy.

RESULTS

No patient reported respiratory problems. Aspiration occurred in 33.3% (MFT), 41.6% (FLPL) and 16.6% (LC). Voice quality was rated as good/satisfactory by 17 MFT patients (62%), satisfactory/sufficient by 69% of FLKT patients, and sufficient/poor by 75% of LC patients.

CONCLUSIONS

The modified false vocal fold flap effectively covers defects and creates a neocord that ensures good phonatory rehabilitation and has positive effects on postoperative quality of life.

Chondrocytes suspended in modified fibrin glue for vocal fold augmentation: An in vitro study in a porcine larynx model

BACKGROUND

Injection laryngoplasty is an option for treatment of dysphonia following vocal fold paralysis. Modified fibrin glue with suspended chondrocytes might be a favorable cell-based material for permanent vocal fold medialization.

METHODS

We compared fibrin glue with suspended chondrocytes to collagen and hyaluronic acid gels concerning alteration of vocal fold vibration and correct intralaryngeal placement after intralaryngeal injection into porcine larynges. Viscoelastic properties of the materials were analyzed by means of a parallel plate rheometer.

RESULTS

Fibrin glue with cells was comparable to collagen and hyaluronic acid with respect to amplitudes, symmetry, and periodicity of vocal fold vibration. Application and positioning of fibrin glue with suspended chondrocytes were technically undemanding and comparable with controls. Complex stress modulus of fibrin glue with suspended cells was comparable to that of collagen gel.

CONCLUSIONS

Fibrin glue with suspended chondrocytes seems suitable for the indication of injection laryngoplasty and holds promise for permanent vocal fold medialization.

[Unilateral extended medialization thyroplasty. Treatment for total aspiration after laser surgery and radiotherapy of laryngeal cancer]

BACKGROUND

Total aspiration is a rare complication after extended laser surgery for laryngeal cancer with adjuvant radiotherapy.

PATIENTS AND METHODS

Two patients with long-standing total aspiration after laser surgery with radiotherapy despite intensified swallowing therapy were treated with an extended medialization thyroplasty.

RESULTS

Postoperatively, both patients were able to swallow food and liquids without aspiration. One patient no longer has a gastrostomy tube and has been free from aspiration with normal oral food intake for 3 years. The second patient, with a tiny mucosal scar perforation, developed an abscess 2 months after surgery and needed revision surgery, with a subsequent return of aspiration.

DISCUSSION

The second patient's complication stresses the significance of an intact endolaryngeal scar because of the well-known prolonged healing of mucosa in the irradiated larynx. In our opinion, the potential benefits of medialization thyroplasty outweigh the risk of significant complications, especially after irradiation.

Perineurioma originating from the recurrent laryngeal nerve, and the phonochirurgical treatment of the developed vocal fold palsy

Perineurioma is a rare, benign tumour of the perineurium, which develops mostly on the nerves of the extremities. The neoplasm related to a genetic mutation on the 22nd chromosome, is a rarity on the vagal nerve branches. Authors report the case of a 15-year-old female with an immunhistochemically verified (focal EMA positive, vimentin, CD56 positive) perineurioma originating from the left recurrent laryngeal nerve. After the removal of the tumour together with the involved 2-cm-long part of the nerve, vocal fold palsy developed with aphonia (left vocal fold was in intermedian position). The treatment had to be chosen carefully as the larynx was still in growth. In our case there was no possibility of spontaneous regeneration, thus we chose lipoaugmentation of the left vocal fold, which does not affect the laryngeal framework, so causes the least harm to the larynx. Following surgery the patient's voice reached the normal range (before lipoaugmentation perception (0-100): G40 B80 R40 Acoustics: Ji 1.1%, Shi 10.8% Harmonicity: 13.9 dB maximum phonation time (MPT) 5 s after augmentation, Perception: G10 B10 R20, Acoustics: Ji 0.3 %, Shi 2.6%, Harmonicity: 21.2 dB MPT 22 s). This result was permanent, as the regularly performed objective voice evaluations confirmed during the 2-year follow-up.