Hirohito Umeno

Functional Histology of the Macula Flava in the Human Vocal Fold – Part 2: Its Role in the Growth and Development of the Vocal Fold

Objective: This study aims to clarify the role of the maculae flavae (MFe) during growth and development of the human vocal fold mucosa (VFM). Methods: Our current results concerning the MFe in the human newborn, infant, and child VFM are summarized. Results: Newborns already had immature MFe at the same sites as adults. They were composed of dense masses of vocal fold stellate cells (VFSCs), whereas extracellular matrix components were sparse. VFSCs in the newborn MFe had already started synthesizing extracellular matrices (EM). During infancy, the EM synthesized in the MFe appeared in the VFM to initiate the formation of the three-dimensional extracellular matrix structure of the human VFM. During childhood, MFe including VFSCs continued to synthesize EM such as collagenous, reticular, and elastic fibers, and hyaluronic acid (glycosaminoglycan), which are essential for the human VFM as a vibrating tissue. The MFe in newborns, infants and children were related to the growth and development of the human VFM. Conclusion: Human MFe including VFSCs were inferred to be involved in the metabolism of EM, essential for the viscoelasticity of the human VFM, and are considered to be an important structure in the growth and development of the human VFM.

Laryngeal Behavior in Unilateral Superior Laryngeal Nerve Paralysis

Laryngeal behavior in unilateral superior laryngeal nerve (SLN) paralysis was investigated in animal models and clinical cases. The occurrence of an oblique glottis caused by rotation of the posterior glottis to the paralytic side was the main focus of this study. The animal model study employed live dogs. When the SLN on one side was sectioned, spontaneous phonation did not cause a significantly oblique glottis. When the unaffected SLN was electrically stimulated during spontaneous phonation, an oblique glottis occurred. When the SLN was unilaterally stimulated during spontaneous phonation with both SLNs sectioned, a markedly oblique glottis occurred. In the clinical study, larynges of 17 patients with SLN paralysis were examined during a test task in which a low-pitched phonation was followed by a high-pitched phonation. The purpose of this task was to activate the unaffected cricothyroid muscle during the test phonation. Five patients could not perform the test task. The glottis obviously rotated in 9 patients, whereas no significant rotation of the glottis occurred in 3. One of the latter 3 had an incomplete paralysis, and the other 2 had marked scarring around the laryngeal framework. We conclude that a unilateral SLN paralysis causes a rotation of the posterior glottis to the paralytic side when the unaffected cricothyroid muscle is markedly activated. The test consisting of low-pitched phonation followed by high-pitched phonation is a relatively simple and accurate diagnostic procedure for unilateral SLN paralysis.

Functional histology of the macula flava in the human vocal fold--Part 1: its role in the adult vocal fold.

Objective: This study aims to clarify the role of the maculae flavae (MFe) in the human adult vocal fold mucosa (VFM). Methods: Our current results concerning MFe in the human adult VFM are summarized. Results: MFe were found to be composed of dense masses of vocal fold stellate cells (VFSCs) and extracellular matrices (EM), such as fibrous proteins and glycosaminoglycans, which are essential for the EM in the human VFM. VFSCs in the MFe demonstrated marked morphologic differences from conventional fibroblasts. They were irregular and stellate in shape and possessed slender cytoplasmic processes. They had well-developed intracellular organelles. A number of vesicles were present at the periphery of the cytoplasm. They constantly synthesized EM. The VFSCs possessed lipid droplets and stored vitamin A. VFSCs formed an independent cell category of cells in the human VFM. The VFSCs in aged adult MFe decreased their activity, and had abnormal metabolism. Conclusion: Human MFe including VFSCs seem to be involved in the metabolism of EM which are essential for the viscoelasticity of the lamina propria of the VFM, and to be responsible for maintaining the characteristic layered structure of the human VFM. Age-related changes in VFSCs were found to influence the metabolism of EM in the VFM.

Analysis of voice function following autologous fat injection for vocal fold paralysis

OBJECTIVE: This study demonstrates that intravocal fold injection of autologous fat obtained by liposuction technique is simple, and the functional results durable for patients with unilateral vocal fold paralysis due to injury to the recurrent laryngeal nerve. STUDY DESIGN: 41 patients with unilateral paralysis of the vocal fold due to injury to the recurrent laryngeal nerve received intravocal fold injection of autologous fat. Autologous fat, harvested from the lower abdomen by liposuction technique, was filtered out and injected through a needle into the vocal fold by using endolaryngeal microsurgery. Clinical follow-up after the injection was carried out from 1 month to 2 years. RESULTS: Voice function dramatically improved compared with the parameters examined before the operation. Vocal function continued to improve as time passed during the second year after injection. CONCLUSIONS: Intravocal fold injection of autologous fat obtained by liposuction technique is simple, and the functional results durable for patients with unilateral vocal fold paralysis due to injury to the recurrent laryngeal nerve. SIGNIFICANCE: The effectiveness continued for more than 2 years in most patients.

Vocal Fold Stem Cells and Their Niche in the Human Vocal Fold

Objectives: Vocal fold stellate cells (VFSCs) in the maculae flavae have many morphological differences from conventional fibroblasts in the human vocal fold mucosa. It is uncertain whether the VFSCs are derived from the same embryonic source as conventional fibroblasts. The purpose of this study was to investigate the stemness of the VFSCs and whether the pericellular matrices in the maculae flavae are a hyaluronan-rich matrix, which is required for a stem cell niche. Methods: Paraffin-embedded specimens were stained with Alcian blue (pH 2.5) for a hyaluronidase digestion study. Immunoreactivity to antibodies directed to CD44, CD133, Oct-4, Ki67, and telomerase was investigated in 5 human adult vocal fold mucosae. Results: The VFSCs were resting cells (G0-phase) and expressed a mesenchymal stem cell marker. The VFSCs did not express hematopoietic or embryonic stem cell markers. Telomerase resided in the VFSCs. The hyaluronan concentration in the maculae flavae was high and the VFSCs expressed hyaluronan receptors, indicating that maculae flavae are characterized by a certain criterion of hyaluronan-rich matrix. Conclusions: There is growing evidence that the VFSCs in the human maculae flavae are somatic (mesenchymal) stem cells of the vocal fold, and that the maculae flavae may be a candidate for a stem cell niche that is a microenvironment nurturing a pool of VFSCs.

Unilateral associated laryngeal paralysis due to varicella-zoster virus: virus antibody testing and videofluoroscopic findings

The relationship between varicella-zoster virus and idiopathic associated laryngeal paralysis was examined in five patients, using complement fixation or enzyme immunoassay testing. In all cases, significant changes in serum levels of varicella-zoster virus antibody were observed. Videofluoroscopy was useful in assessing the severity of the dysphagia and in making an accurate diagnosis; both laryngeal elevation and weakness of pharyngeal wall contraction were also observed. In two cases in which antiviral therapy was delayed, the outcome was poor, with increased levels of varicella-zoster virus immunoglobulin M found on enzyme immunoassay. The outcome of the condition may thus depend both on the speed of antiviral therapy commencement following onset of symptoms, and on the levels of varicella-zoster virus immunoglobulin M antibody (measured by enzyme immunoassay). Our study suggests that varicella-zoster virus should be considered in the differential diagnosis of patients with idiopathic associated laryngeal paralysis, and rapid antiviral therapy should be initiated when necessary.

Clinical study of parapharyngeal space tumours

This study reviewed 24 cases of parapharyngeal space tumour treated at Kurume University Hospital between 1990 and 2007. Histological diagnoses were generally obtained from the excised tumour (22/24). Seventy-seven per cent of the parapharyngeal space tumours were benign and 23 per cent were malignant. Thirty-eight per cent (eight of 22) of these tumours were pleomorphic adenomas and 23 per cent (five of 22) were schwannomas. A transparotidectomy and transcervical approach were used in 88 per cent (15/17) of benign tumours. A mandibular swing approach was used for one malignant tumour. Post-operative complications were identified in 16 of 22 patients. The most common complication, facial nerve paralysis, was identified in eight patients, and seven of these patients demonstrated first bite syndrome. In consideration of the high incidence of post-operative complications, the surgical approach should therefore be carefully selected when treating patients with parapharyngeal space tumours.

Autologous fat injection laryngohypopharyngoplasty for aspiration after vocal fold paralysis.

Injection laryngoplasty is one of the procedures for treating unilateral vocal fold paralysis. This is a preliminary report on modified injection laryngoplasty, ie, injection of liposuctioned autologous fat into the larynx and hypopharynx of patients who have aspiration and voice disorders after vocal fold paralysis. Lipoinjection was performed in 3 patients with these complaints with the endolaryngeal microsurgical technique under general anesthesia. The locations of fat injection were the vocal fold, the false vocal fold, the aryepiglottic fold of the larynx, and the medial wall of the pyriform sinus of the hypopharynx. Lipoinjection into the vocal fold, false vocal fold, and aryepiglottic fold strengthened laryngeal closure. Lipoinjection, performed into the thyroarytenoid muscle lateral to the oblong fovea of the arytenoid cartilage, made arytenoid cartilage rotation possible, and consequently strengthened laryngeal closure. Lipoinjection into the medial wall of the pyriform sinus of the hypopharynx reduced its capacity; consequently, the amount of residual food retained in it was reduced and pharyngeal clearance on the affected side was improved. The longest follow-up among the 3 patients has been 24 months. Their aspiration and glottal incompetence have been improved by this operation. We conclude that modified injection laryngoplasty (laryngohypopharyngoplasty) is one of the surgical options for preventing aspiration after vocal fold paralysis.

Origin of Vocal Fold Stellate Cells in the Human Macula Flava

Objectives: There is growing evidence that vocal fold stellate cells (VFSCs) in the human maculae flavae are tissue stem cells of the human vocal fold and that the maculae flavae are a stem cell niche. The origin of the cells in the human maculae flavae (CHMF) and the relationship with bone marrow–derived cells were investigated. Methods: Five human adult vocal fold mucosae were investigated. The CHMF were subcultured and morphological features were assessed. Immunoreactivity to antibodies directed to cytokeratin, desmin, GFAP, vimentin, CD34, CD45, and collagen type I was investigated. Results: Cultured CHMF formed a colony-forming unit, indicating they are mesenchymal stem cells or stromal stem cells in the bone marrow. The CHMF expressed hematopoietic markers (CD34, CD45) and collagen type I, which are the major makers for bone marrow–derived circulating fibrocytes. The cultured CHMF expressed epithelium-associated, muscle-associated, neural-associated, and mesenchymal cell–associated proteins, indicating the CHMF are undifferentiated and express proteins of all 3 germ layers. Conclusions: The CHMF are undifferentiated cells derived from the differentiation of bone marrow cells. The results of this study are consistent with the hypothesis that the VFSCs are tissue stem cells or progenitor cells of the human vocal fold mucosa.

Long-Term Postoperative Vocal Function after Thyroplasty Type I and Fat Injection Laryngoplasty

Objectives: We evaluated the differences in the long-term functional results of medialization thyroplasty type I (MT) and autologous fat injection laryngoplasty (FIL) in patients with unilateral vocal fold paralysis. Methods: Forty-one patients underwent MT, and 73 patients underwent FIL. The voice functions before and after both surgeries were examined by aerodynamic, pitch and intensity, and acoustic analyses. The postoperative voice examinations were performed 12 months (median) after the MT, and 4 years (median) after the FIL. The differences between the preoperative and postoperative parameters were examined with a paired t-test for each group separately. For each variable, a comparison of the effects of surgery was conducted with an analysis of covariance model, with the change between the preoperative and postoperative values as the dependent variable and the preoperative value as the covariate. Results: In both groups, all parameters significantly improved after surgery. In particular, there was a significant difference for the postoperative acoustic analyses. However, the aerodynamic analysis after FIL improved more significantly in comparison to that after MT because of the respiratory handicap. Conclusions: We found that MT and FIL provided almost the same effectiveness, and that both surgeries were reliable in improving the vocal function in patients with vocal fold paralysis.