Principles of tissue engineering include scaffold materials, stem cells and regulatory factors. With the availability of blood supply, an organ can be regenerated. Scaffold materials such as collagen, hydroxyapatite and polylactic acid, stem cells such as mesenchymal stem cells (MSC), adipose tissue derived stem cells (ASC) and induced pluripotent stem (iPS) cells, and regulatory factors such as basic FGF, IGF-1 and HGF have been utilized. Langer and Vacanti proposed “tissue engineering,” wherein they proposed creating tissues outside the body and then implanting them into the body; however, their implanted tissues became absorbed in the body in animal experiments. In contrast, our concept of “in situ tissue engineering” is designed to mediate the healing and tissue re-growth within the body itself.

An artificial trachea made from a non-absorbable polypropylene mesh tube covered by an absorbable porous and microcellular collagen sponge as a scaffold was implanted into the defect of the cricoid and trachea in beagles. Based on the successful outcome in animal experiments as proof of concept, with approval from the IRB, we implanted the artificial trachea for repair of an airway defect in a human. The successful outcome of this clinical research indicates the feasibility of using an artificial trachea in regenerative medicine of the larynx and cervical trachea. For practical use in Japan, it is necessary to comply with official regulations, such as the biological safety test on Good Laboratory Practice (GLP), safe production and quality control of medical equipment on Quality Management System (QMS), and an accurate, ethical and efficient clinical trial on Good Clinical Practice (GCP).

Further basic studies are in progress for accelerating epithelization and regenerating the cartilage tissue of the trachea. Cell sources such as fibroblasts, MSC, ASC and iPS cells have been utilized for regeneration of the tracheal epithelium. Grafts of a collage sponge combined with chondrocytes or iPS cells derived cartilage-like cells have been developed for regeneration of cartilage tissue. For regeneration of the bulging and multilayered structure of the vocal folds, use of de-cellularized tissue and regulatory factors has been attempted. Translational research from bench to the bedside will be required to establish regenerative medicine of the larynx and trachea.

Grafting of cartilage has been recognized as useful for tympanoplasty of retracted ear drums or ear drums with high-risk perforation.

During cartilage tympanoplasty, the cartilage for the graft is generally sliced very thin so as to have it much the ear drums in morphology and functionality.

However, thinly sliced cartilage often curls unacceptably towards the side with perichondrium, making placement difficult and less precise.

A perichondrium/cartilage island flap made from full-thickness tragal cartilage is an excellent graft, as it allows a better fit in the middle ear and never curls.

We used a tragal perichondrium/full-thickness cartilage island flap for cartilage tympanoplasty in 26 cases of high-risk perforations of the tympanic membrane. The perichondrium, backed with full-thickness cartilage, led to rapid epithelialization of the ear drum.

After removing a small V-shaped cartilage at the top of the flap to accommodate the short process and handle of the malleus, we placed the island flap in an overlay fashion.

The closure rate of the tympanic membrane in the patients who underwent tympanoplasty using a tragal perichondrium/cartilage island flap was 100%. According to the guideline for reporting hearing results for middle ear and mastoid surgery (2010) proposed by the Japan Otological Society, the hearing results of tympanoplasty using a full-thickness tragal island flap were better than those of surgery using a thinly sliced cartilage.

Because use of a full-thickness cartilage allows more precise reconstruction and better hearing results than that of thinly sliced cartilage, we recommend the use of full-thickness grafts for cartilage tympanoplasty.

The three cardinal signs of the complete form of Ramsay Hunt syndrome are facial nerve palsy, herpes zoster oticus, and 8^th nerve dysfunction.

We encountered a patient with Ramsay Hunt syndrome who exhibited herpes zoster oticus without facial nerve palsy (Haymann type IV). A 54-year old male complaining of vertigo and hearing loss on the left side associated with pain and a skin rash in the left ear and headache was referred to our hospital. Examination of the hearing and vestibular functions revealed left-sided sensorineural hearing loss and canal paresis with spontaneous horizontal and rotary nystagmus, but no evidence of facial palsy. Reactivation of varicella zoster virus (VZV) was concluded from the elevated VZV-specific serum IgM and IgG antibody levels and result of analysis of saliva by PCR assay. Cerebrospinal fluid examination revealed findings consistent with viral meningitis. Finally, the patient was diagnosed as having Ramsay Hunt syndrome of the incomplete type (Haymann type IV) with viral meningitis, and was initiated on treatment with acyclovir and prednisolone. Both the headache and herpetic vesicles responded well to the treatment. However, the left-sided total sensorineural hearing loss, positional nystagmus to the right, and canal paresis on the left persisted for eleven months.

Cochleovestibular symptoms with Haymann type IV Ramsay Hunt syndrome are presumably associated with VZV reactivation in the spiral and/or vestibular ganglion, but not in the geniculate ganglion. Previous reports have revealed the poor prognosis of 8^th nerve dysfunction and risk of central nervous complications in patients with Haymann type IV Ramsay Hunt syndrome. Therefore, attention should be paid to the presence of the central nervous symptoms in such patients.

Cerebrospinal fluid (CSF) rhinorrhea is a disorder of the skull base in which the CSF flows into the nasal sinuses. Such traffic between the skull and nasal cavities can cause intracranial infections. Cerebrospinal rhinorrhea has been broadly classified as traumatic and atraumatic CSF rhinorrhea. Traumatic CSF rhinorrhea is usually caused by head injuries or nasal sinus surgery, and atraumatic CSF rhinorrhea can be idiopathic or congenital, or result from infiltration tumors of the paranasal sinuses and skull base tumors. Traumatic CSF rhinorrhea has been reported to occur in about 2% of cases of head trauma. There are few reports of atraumatic CSF rhinorrhea. Especially, that of idiopatic causation is said to be rare. Diagnosis is based on the symptoms, imaging findings, and detection of CSF-specific protein or glucose in the nasal discharge. Conservative treatment is the approach of first choice for the management of traumatic CSF rhinorrhea, and surgical treatment is the treatment of first choice for atraumatic CSF rhinorrhea. The surgical approach could be intracranial or extracranial. With the advances in endoscopic sinus surgery techniques, transnasal endoscopic repair has become mainstream. We report an example of treatment of a case of spontaneous CSF rhinorrhea by endoscopic sinus surgery.

Epulis refers to reactive tumor-like gingival enlargement. The main causes of epulis are local irritation by calculi, bacterial plaques, caries, or restorations with irregular margins. Epulis appears in the interdental papilla and is treated mostly by dentists. It is known to be a benign condition and to progress slowly. In some cases, however, it may become quite large and mimic a malignant tumor. In such cases, otolaryngologists should take responsibility for differential diagnosis.

A 64-year-old woman was referred to use for the evaluation of a large painless gingival mass. After biopsy, the lesion was diagnosed as not being a malignant tumor, but epulis. It was removed by operation, with complete epithelialization obtained in approximately seven months.

To prevent unnecessary surgery, it is necessary to make an accurate diagnosis prior to treatment.

Mumps virus is one of the major causative pathogens of sialadenitis. Some cases of laryngopharyngeal edema developing in association with mumps virus infection have been reported in Japan. We report three cases of suspected mumps virus infection who presented with laryngopharyngeal edema.

(Case 1) A 27-year-old female patient presented to us with the chief complaint of swelling and pain of the parotid gland region and breathlessness. Endoscopic examination showed significant laryngopharyngeal edema. Intravenous administration of a steroid proved ineffective against the edema. Then, we decided to secure the airway by oral intubation. The laryngopharyngeal edema gradually resolved and the patient was extubated on day 3 of hospitalization. Although the patient gave a history of having received vaccination against mumps infection, the serum test for IgM antibody against mumps virus was positive. Therefore, she was diagnosed as a case of mumps with primary vaccine failure.

(Case 2) A 44-year-old male patient presented to us with the chief complaint of swelling of the upper neck. Endoscopic examination revealed laryngopharyngeal edema, which resolved promptly with intravenous administration of a steroid. Mumps was ruled out by a negative serum test for mumps virus antibodies and a negative virus isolation test of the saliva. We suspected the cause to be a viral infection other than mumps.

(Case 3) A 29-year-old female patient presented to us with the chief complaint of swelling and pain of the parotid region and sore throat. Endoscopic examination revealed significant laryngopharyngeal edema, which resolved gradually with intravenous steroid administration. The causative pathogen in this case also remained unknown, as in Case 2.

Among the three cases, mumps virus infection was confirmed in one case, whereas the cause in the other two cases was considered to be a virus other than mumps virus. Patients with sialadenitis presumed to be caused by viral infection who present with the complication of laryngopharyngeal edema should be treated with intravenous steroid and be examined frequently by endoscopy.

Pyriform sinus fistula, a congenital deformity derived from the third, fourth or fifth branchial cleft, is often the cause of acute suppurative thyroiditis and neck abscess among young subjects. It is mostly found on the left side. Herein, we report a rare case of a right-sided pyriform sinus fistula. A 28-year-old woman presented with a history of four episodes of right neck abscess in the previous four years. We suspected that the episodes of neck abscess were caused by the presence of a pyriform sinus fistula. However, neither CT nor barium hypopharyngography revealed the presence of a fistula. Finally, direct laryngoscopy under general anesthesia led to the diagnosis of the right-sided pyriform sinus fistula. After injection of pyoktanin into the fistula opening, the fistula was identified by a cervical approach and completely removed. The patient’s clinical course after the surgery was uneventful, and there has been no recurrence. Direct laryngoscopy is considered as a useful tool for the diagnosis of pyriform sinus fistula, especially when the fistula cannot be identified by any other modality, including barium hypopharyngography.

Thyroglossal duct cyst is the most commonly seen of midline congenital neck masses. We encountered a case of endolaryngeal extension of a thyroglossal duct cyst. A 66-year-old man presented to us complaining of a swelling in the neck and an abnormal sensation in the throat. A cystic lesion was suspected on magnetic resonance imaging, and CT showed a normal thyroid in the anterior neck. Considering the two finidings together, we made the diagnosis of a thyroglossal duct cyst. The differential diagnosis of a cystic lesion in the larynx include laryngocele and saccular cyst. In this case, the cyst enlarged gradually from an extralaryngeal position into the larynx through the thyrohyoid membrane and into the paraepiglottic space. A thyroglossal cyst can sometimes cause dyspnea, and such patients must be followed up carefully.

Objective: Hypothyroidism is a noteworthy complication after hemithyroidectomy, and its reported frequency varies widely in the range of 22%–56%. If we can predict thyroid function after hemithyroidectomy, it would help us to explain the risk of post-operative hypothyroidism to the patient.

Method: We reviewed the data of 93 patients who underwent hemithyroidectomy between January 2013 and December 2015. Patients with pre-operative hypothyroidism or receiving TSH suppression therapy postoperatively were excluded. We investigated the prevalence of post-operative hypothyroidism, the interval between surgery and the development of hypothyroidism, the risk factors for hypothyroidism, and the need for thyroid hormone replacement therapy in the study subjects.

Results: Post-operative hypothyroidism developed in 36 patients (39%). It was detected after an interval of less than one month in 23 patients, less than 6 months in 4 patients, less than 12 months in 5 patients, and more than 12 months in 4 patients. Among the 35 patients with subclinical hypothyroidism, 21 exhibited permanent hypothyroidism, and in most, the interval between surgery and the development of hypothyroidism was short. Eighteen patients required thyroid hormone replacement therapy. Only pre-operative serum TSH was identified as being significantly associated with the development of hypothyroidism (p<0.01). On the other hand, the age, sex, histology (benign/malignant), operation side, and presence/absence of anti-Tg antibody and anti TPO antibody were not found to be significant. Pre-operative TSH>1.95 was the effective cut-off value for determining the need for thyroid hormone replacement therapy.

Conclusion: Post-operative hypothyroidism developed in about 40% of the patients, with 20% requiring thyroid hormone replacement therapy. Patients who developed hypothyroidism within a short interval after the hemithyroidectomy were more likely to need hormone replacement therapy. Pre-operative serum TSH level was a good predictor of the risk of post-operative hypothyroidism and of the need for hormone replacement therapy. These results lend support to the recommendation for close thyroid function follow-up after surgery in patients with relatively high pre-operative serum TSH levels within the normal range.

There has been discussion on the problem of increasing medical costs associated with aging of the society in Japan, which has led to the current promotion of home care. Although home care is provided mainly for conditions in the field of internal medicine, otolaryngologists also play a significant role. From our clinic, home visits were provided for 183 patients (a total of 483 visits) over the course of 3 years and 10 months, from March 2013 to December 2016. Of the visits, 75.2% were for the treatment of dysphagia, in cooperation with home-visit nursing rehabilitation stations. The second most common indication for the home visits was auditory disorders, including hearing loss, followed by management of the trachea and malignant tumors of the head and neck. Since many elderly suffer from dysphagia and hearing loss, otolaryngologists can play an important role in increasing the QOL of these patients at home. There are various problems in the delivery of home care by otolaryngologists and these concerns should be actively addressed.

Prosper Menière published his famous original paper about vertigo in 1861. Since then, his name has appeared in the literature spelled in several different ways, such as Ménière, Menière or Meniere. Previously, Menière was the most commonly used in Europe, and Ménière in the USA. However, in recent publications Ménière, Menière and Meniere have been used interchangeably. Even on the tombstones of Prosper Menière and his family, the spelling of the family name varies: Prosper Ménière, Emile Menière and Michel Meniere.