The optimal timing of functional endoscopic sinus surgery for odontogenic infections precipitated by retention cysts of the maxillary sinus was investigated.

Five adults who underwent functional endoscopic sinus surgery were examined.

The root apexes of all teeth that had odontogenic infection protruded into the maxillary sinus. All teeth with odontogenic infections precipitated by the retention cysts had percussion pain, indicating they had periodontitis and pulpitis around the root apex. They were vital teeth, indicating they did not have pulp necrosis. The small area of cyst wall attached to the floor of the maxillary sinus and root apex were left intact. The teeth that had odontogenic infections precipitated by retention cysts continued to be vital with no symptoms.

Functional endoscopic sinus surgery should be performed before periodontitis and pulpitis of the root apex progress to ascending pulpitis and pulp necrosis. In other words, functional endoscopic sinus surgery should be performed while the affected tooth is still vital.

Cells in the vocal fold of maculae flavae are likely to be tissue stem cells. Energy metabolism of the cells in newborn maculae flavae was investigated from the aspect of mitochondrial microstructure.

Five normal newborn vocal folds were investigated under transmission electron microscopy.

Mitochondria consisted of a double membrane bounded body containing matrices and a system of cristae. However, these membranes were ambiguous. In each mitochondrion, the lamellar cristae were sparse. Intercristal space was occupied by a mitochondrial matrix. Some mitochondria had fused to lipid droplets and rough endoplasmic reticulum, and both the mitochondrial outer and inner membranes had incarcerated and disappeared.

The features of the mitochondria of the cells in the newborn maculae flavae showed that their metabolic activity and oxidative phosphorylation were low. The metabolism of the cells in the newborn maculae flavae seems to be favourable to maintain the stemness and undifferentiation of the cells.

In order to improve a large posterior glottal gap and/or aspiration, injections of augmentation substances should not only be administered at the mid-membranous vocal fold in the thyroarytenoid muscle, but also at the cartilaginous portion of the vocal fold to make adduction arytenopexy possible.

Ten adult human larynges were investigated using the whole-organ serial section technique.

Vertical thickness of the posterior aspect of the thyroarytenoid muscle was relatively thin (3.4 ± 0.4 mm), especially in females (3.2 ± 0.3 mm). Consequently, care should be taken to ensure the correct depth of needle placement. If the needle is placed too deep, augmentation substances are injected into the lateral cricoarytenoid muscle, located beneath the thyroarytenoid muscle, or into the paraglottic space, located inferolateral to the thyroarytenoid muscle.

The injection location and the amount of injected material should be modified based on the pathological conditions of the voice disorder and aspiration.

There is growing evidence that the cells in the maculae flavae are tissue stem cells of the human vocal fold mucosa, and that the maculae flavae are a candidate for a stem cell niche. The role of microenvironment in the maculae flavae of the human vocal fold mucosa was investigated.

Anterior maculae flavae from six surgical specimens were cultured in a mesenchymal stem cell growth medium or a Dulbecco's modified Eagle's medium.

Using mesenchymal stem cell growth medium, the subcultured cells formed a colony-forming unit, and cell division reflected asymmetric self-renewal. This indicates that these cells are mesenchymal stem cells or stromal stem cells in the bone marrow. Using Dulbecco's modified Eagle's medium, the subcultured cells showed symmetric cell division without a colony-forming unit.

A proper microenvironment in the maculae flavae of the human vocal fold mucosa is necessary to be effective as a stem cell niche that maintains the stemness of the contained tissue stem cells.

There is growing evidence to suggest that cells in the maculae flavae are tissue stem cells of the human vocal fold and maculae flavae are a stem cell niche.

Three newborn vocal folds were investigated. Immunoreactivity to antibodies directed to cytokeratin, desmin, glial fibrillary acidic protein, vimentin, cluster of differentiation 34, cluster of differentiation 45, collagen type I, telomerase reverse transcriptase, SOX17 and stage-specific embryonic antigen 3 was investigated.

The cells in the newborn maculae flavae expressed haematopoietic markers (cluster of differentiation 34, cluster of differentiation 45) and collagen type I, which are the major makers of bone marrow derived circulating fibrocytes. The cells expressed epithelium, muscle, neural and mesenchymal cell associated proteins, and endodermal marker, indicating that they are undifferentiated and express proteins of all three germ layers. The cells also expressed stage-specific embryonic antigen 3 and telomerase reverse transcriptase.

The cells in the newborn maculae flavae are undifferentiated cells arising from the differentiation of bone marrow cells. The results of this study are consistent with the hypothesis that the cells in maculae flavae are tissue stem cells.

This study aimed to clarify the local immune status in the larynx in the presence of infection or carcinogenesis associated with human papilloma virus.

Cytological samples (for human papilloma virus detection) and laryngeal secretions (for immunoglobulin assessment) were obtained from 31 patients with laryngeal disease, during microscopic laryngeal surgery. On histological examination, 12 patients had squamous cell carcinoma, four had laryngeal papilloma and 15 had other benign laryngeal disease. Cytological samples were tested for human papilloma virus DNA using the Hybrid Capture 2 assay.

High risk human papilloma virus DNA was detected in 25 per cent of patients (three of 12) with laryngeal cancer. Low risk human papilloma virus DNA was detected only in three laryngeal papilloma patients. The mean laryngeal secretion concentrations of immunoglobulins M, G and A and secretory immunoglobulin A in human papilloma virus DNA positive patients were more than twice those in human papilloma virus DNA negative patients. A statistically significant difference was observed between the secretory immunoglobulin A concentrations in the two groups. Patients with laryngeal cancer had higher laryngeal secretion concentrations of each immunoglobulin type, compared with patients with benign laryngeal disease. The study assessed the mean laryngeal secretion concentrations of each immunoglobulin type in the 12 laryngeal cancer patients, comparing human papilloma virus DNA positive patients (n = 3) and human papilloma virus DNA negative patients (n = 9); the mean concentrations of immunoglobulins M, G and A and secretory immunoglobulin A tended to be greater in human papilloma virus DNA positive cancer patients, compared with human papilloma virus DNA negative cancer patients.

These results suggest that the local laryngeal immune response is activated by infection or carcinogenesis due to human papilloma virus. The findings strongly suggest that secretory IgA has inhibitory activity against infection or carcinogenesis associated with human papilloma virus in the larynx.

This study aimed to introduce the technique of tetra-probe, 24-hour pH monitoring for laryngopharyngeal reflux disease.

Tetra-probe, 24-hour pH monitoring was performed for 30 suspected cases of laryngopharyngeal reflux. The proximal probe was placed in the hypopharynx, just above the upper oesophageal sphincter, the second probe was placed in the middle oesophagus, the third probe was placed a few centimetres above the lower oesophageal sphincter, and the distal probe was placed in the stomach.

As the pH at the four sensor sites could be monitored simultaneously, gastric acid levels and gastroesophageal and laryngopharyngeal reflux could be examined. This pH monitoring technique enabled the pH relationship between the four sensor locations to be well documented, enabling gastric acid levels and patterns of reflux to be assessed. This procedure was also able to be used as a functional examination to evaluate anti-reflux medication efficacy.

Tetra-probe, 24-hour pH monitoring is a reliable functional examination for laryngopharyngeal reflux.

The effectiveness of autologous fat injection laryngoplasty may be reduced by resorption of injected fat tissue. The aim of the present study was to clarify the efficacy of fat injection laryngoplasty using autologous fat plus a replication-defective adenoviral vector expressing hepatocyte growth factor, regarding reduction of injected fat tissue resorption.

Four female beagle dogs were used in this study. After sedation, a direct laryngoscope was introduced to enable visualisation of the larynx. In each dog, harvested autologous fat plus an adenoviral vector expressing hepatocyte growth factor was injected into the right true vocal fold, and harvested fat plus an adenoviral vector expressing no gene was injected into the left true vocal fold. A total laryngectomy was performed one year after the intracordal fat injection. Coronal sections of the resected whole larynges were made and the following parameters assessed using light and electron microscopy: size of fat area; number of vasculoendothelial cells surrounding adipocytes; and shape of injected adipocytes in the vocal fold.

The fat area was significantly larger and the number of vasculoendothelial cells surrounding adipocytes significantly greater in the intracordal fat injection containing adenoviral vector expressing hepatocyte growth factor, compared with the control intracordal fat injection containing adenoviral vector expressing no gene. When viewed under electron microscopy, the injected adipocytes were observed to have grafted better in the intracordal fat injection with hepatocyte growth factor adenoviral vector, compared with the control intracordal fat injection with adenoviral vector expressing no gene.

Injection into the vocal fold of autologous fat containing an adenoviral vector expressing hepatocyte growth factor can reduce subsequent resorption of injected fat.

To evaluate differences between the functional results of framework surgery and autologous fat injection laryngoplasty, for patients with unilateral vocal fold paralysis.

Sixty-two patients underwent framework surgery, while 64 received autologous fat injection laryngoplasty. Voice function before and after both procedures was assessed using aerodynamic and acoustic analysis, with differences evaluated using paired t-test in both groups.

In both groups, all parameters improved significantly after surgery, compared with before surgery. Post-operative improvement in all parameters was significantly greater after fat injection laryngoplasty, compared with framework surgery.

Autologous fat injection laryngoplasty was thus found to be a more effective and reliable therapy for improving voice function in patients with vocal fold paralysis, compared with framework surgery.

Double-probe, 24-hour pH monitoring remains the ‘gold standard’ for the diagnosis of laryngopharyngeal reflux disease, even though there is no consensus on how to interpret the data collected.

Tetra-probe, 24-hour pH monitoring was performed in 56 patients with suspected laryngopharyngeal reflux, in order to investigate patterns of laryngopharyngeal and gastroesophageal reflux.

The number of reflux episodes and the total and percentage time periods spent with pH < 4.0 were correlated with the distance of the probe from the lower oesophageal sphincter. The number of reflux episodes and the total and percentage time periods with pH < 4.0 were greater when patients were upright (i.e. during the daytime). There were few laryngopharyngeal reflux events recorded for pH levels of <4.0; however, there were a significant number of laryngopharyngeal reflux events recorded for pH levels of <5.0, a level capable of causing laryngopharyngeal reflux disease. When a pH level of <5.0 was used, the number, total time and percentage time of laryngopharyngeal reflux episodes was greater during the supine period (i.e. during sleeping) in a quarter of the cases, compared with results when a pH of <4.0 was used.

It is valid to use a pH level of 5.0 as indicative of laryngopharyngeal reflux in the hypopharynx.