Since nystagmus, in which the eyeballs move rhythmically from side to side, is not observed immediately after birth, the term congenital nystagmus has been replaced by the term infantile nystagmus in recent years. Patients with infantile nystagmus exhibit impaired gaze fixation, horizontal smooth pursuit and optokinetic nystagmus (OKN), and use saccadic eye movements for these underlying impairments. In order to induce saccades, they make a sufficient angle between gaze and target by precedent exponential slow eye movements. Infantile nystagmus consists of the alternate appearance of saccades and slow eye movements, so that it is therefore considered as a necessary strategy for obtaining better vision and not an obstacle to clear vision. Because patients follow the moving target during the fast and not the slow phase of nystagmus, the lines obtained by connection of the end eye positions during the fast phase of nystagmus coincide with the trajectories of the targets. By setting the direction of the slow phase of nystagmus in a direction opposite to the direction of the OKN stimulus, a sufficient angle can be effectively obtained between the gaze and target for the induction of saccade. This is the mechanism of the reversed OKN response.

A negative feedback mechanism exists for controlling the eye movements in healthy people. In the case of infantile nystagmus, if the line of sight deviates slightly from a stationary target, it is impossible to induce a small saccadic eye movement to correct for the small deviation with saccadic eye movement. Therefore, the deviation must be increased, and control to move the eye movement away from the target is necessary, so that a positive feedback mechanism is used. The output under control by the positive feedback mechanism changes exponentially. Because the slow phase of infantile nystagmus is controlled by a positive feedback mechanism, the position and velocity data of the slow phase change exponentially.

We present a rare case of squamous papilloma of the external auditory canal and tympanic membrane that disappeared temporarily after biopsy and then recurred several months later, with perforation of the tympanic membrane. A 67-year-old female patient with a 11-year history of left-sided ear blockage visited our hospital complaining of left-sided hearing loss and otorrhea. Otoscopic examination revealed a papillomatous lesion in the bony part of the left external auditory canal, with extension to the tympanic membrane. Histopathological examination of a biopsy specimen showed moderately acanthotic papillary squamous epithelium, without atypia. The papillomatous lesion disappeared 20 days post-biopsy. However, the papillomatous lesion recurred, and perforation of the left tympanic membrane was found 122 days later. The patient underwent successful canalplasty and myringoplasty. The final histopathological finding was squamous papilloma. There has since been no sequela or relapse until date, 2 years 9 months since the surgery.

It is possible that the biopsy of the squamous papilloma triggered an immune response that led to regression of the lesion in our immunocompetent patient. Clinical follow-up is considered necessary because any immune suppression may cause recurrence of the disease.

There are few published reports about keratosis obturans (external auditory canal cholesteatoma), and the pathogenesis and diagnostic criteria remain unclear. Herein, we report a rare pediatric case of keratosis obturans who presented with severe otalgia. The patient was a 7-year-old girl with a 4-year history of intermittent otalgia for which she had been receiving treatment from a local doctor. She had been diagnosed as having parotitis and otitis externa. However, in the 6 months prior to her first visit to our department, her pain had become more severe, failed to be controlled even with painkillers, and she had begun to cry repeatedly at night. Examination revealed that her right ear canal was filled with cerumen and ear discharge, but she failed to cooperate for a more detailed examination. Thus, we were unable to treat her adequately at first. A temporal bone CT showed a soft shadow filling the external auditory canal, middle ear, and mastoid, and extensive destruction of the bony external auditory canal. Based on the findings, we made the diagnosis of keratosis obliterans (external auditory canal cholesteatoma). We treated the patient by endoscopic ear surgery performed under general anesthesia 9 days after her first visit to our department. The otalgia resolved and she stopped crying at night immediately after the surgery. Until date, 18 months since the surgery, the ear canal has remained self-cleaning. Keratosis obliterans is a disorder in which the self-cleaning function of the external auditory canal is impaired and cornified epithelium accumulates in the external auditory canal, resulting in pressure dermatitis. No diagnostic criteria have been established to clearly distinguish this condition from external auditory canal cholesteatoma. There is no consensus on the treatment of external auditory canal cholesteatoma. Surgical treatment is considered as being indicated in children when bone destruction is extensive, when there is infection caused by resistant bacteria that is refractory to treatment, when the external auditory canal is narrowed, and when there is no improvement in response to outpatient treatment. We report this patient to underscore the need for caution against a delay in the diagnosis which could lead to severe complications.

We successfully performed BONEBRIDGE implantation under the guidance of a head-mounted holographic display in a patient with bilateral external auditory canal atresia. The surgeon wore a HoloLens and projected a hologram onto the patient under the general anesthesia. The hologram was aligned with the patient’s auricle as a reference, when marking the skin incision line and implantation site. After exposing the temporal bone, the hologram was re-aligned to allow reference to the fine irregularities and fusion lines on the bone surface. The implantation site was drilled as planned and the operation was successfully completed without the need to expose the dura mater or sigmoid sinus. The patient was discharged from the hospital without any postoperative complications. Holography-assisted surgery is a useful method for implanting a BONEBRIDGE, particularly in cases without the usual external anatomical markers, such as cases with external auditory canal atresia.

Iatrogenic foreign bodies can cause maxillary sinusitis. Herein, we report two cases of patients in whom gutta-percha, a filling material used in root canal treatment, was identified as a foreign body in the right maxillary sinus. Gutta-percha is commonly used in dentistry, and occasionally it penetrates the root apex to stray into the maxillary sinus. CT is commonly used for the diagnosis, but caution is required, as it could be missed, depending on the site at which it is lodged. Treatment is surgical removal, which may be difficult depending on the location. In both the cases reported herein, we performed endoscopic resection, with good outcomes. Gutta-percha points can cause maxillary sinusitis, and it is important to diagnose and treat these patients without leaving any residual foreign body or residual postoperative symptoms.

Compensatory lingual tonsillar hypertrophy may occur after palatine tonsillectomy. We report a case of compensatory hypertrophy of the lingual tonsils developing after extraction of the palatine tonsils, with hemorrhage caused by lingual tonsillitis, which was difficult to distinguish from malignant lymphoma of the base of the tongue.

A 70-year-old man was brought to the emergency room complaining of sore throat, halitosis, and hemoptysis. Examination revealed swelling at the base of the tongue and hemorrhage from the same area. Cervical lymphadenopathy was observed. Based on the findings, we suspected malignant lymphoma of the base of the tongue. After tracheostomy, two biopsy specimens were obtained from the base of the tongue, and examination revealed that both contained normal tonsillar tissue. Later, detailed medical history-taking brought to light the previous history of palatine tonsillectomy. Based on the history and examination findings, we made the diagnosis of compensatory tonsillar hypertrophy with tonsillitis and hemorrhage. Since then, the swelling at the base of the tongue appears to have shrink, and the patient has had no episodes of bleeding since.

We report a case of compensatory lingular tonsillar hypertrophy with hemorrhage. When compensatory tonsillar hypertrophy is associated with tonsillitis of the tongue and hemorrhage, distinguishing it from malignant lymphoma becomes difficult. Detailed history-taking is important to differentiate among diseases with similar local and laboratory findings.

Non-recurrent inferior laryngeal nerve (NRILN) is reported to occur at incidence of approximately 1% of the population. We encountered two patients with a NRILN observed during thyroid surgery. A 48-year-old female patient and 22-year-old female patient with papillary carcinoma (cT2N0M0 and cT2N0M0, respectively) were treated by right thyroid lobectomy. A NRILN was identified on the right side in both the patients. Preoperative CT showed an abnormal course of the subclavian artery in both patients. It is important for surgeons to be vigilant for a non-recurrent inferior laryngeal nerve before thyroid surgery. Preoperative CT is useful to predict NRILN from an abnormal course of the subclavian artery.

Extracorporeal membrane oxygenation (ECMO) is a life support method for patients with severe respiratory and circulatory failure, that involves the use of an extracorporeal circulatory circuit. Two patients with head and neck cancer in whom endotracheal intubation and tracheotomy under local anesthesia were expected to be difficult and surgery was performed under ECMO support are reported here, with a review of the relevant literature.

Case 1: A 56-year-old man with a one-month history of sore throat and dyspnea was detected by a neighborhood doctor as having a cervical mass, and referred to our hospital. Laryngoscopy showed narrowing of the glottic gap by the tumor. Fine needle aspiration cytology (FNAC) of the mass in the anterior neck revealed squamous cell carcinoma. Imaging studies suggested laryngeal carcinoma or undifferentiated thyroid carcinoma, and the patient was referred for surgery.

Because tracheal intubation and tracheostomy were expected to be difficult due to the large size of the tumor and narrowing of the glottic gap, we decided to perform the surgery under veno-venous ECMO (V-V ECMO) support. No complications arising from the ECMO support were observed in the perioperative period. Histopathological examination of the excised specimen confirmed the diagnosis of laryngeal cancer. At present, the patient remains under observation without any recurrence.

Case 2: A 50-year-old man presented with a 2-month history of bloody sputum. A poorly mobile mass was palpated on the right side of the thyroid gland. MRI showed tumor infiltration extending from the membranous part of the trachea to the lumen over half the circumference of the trachea. FNAC from the right lobe of the thyroid gland showed class V, papillary carcinoma. The patient was diagnosed as having papillary carcinoma of the thyroid (cT4aN0M0), and surgery was planned. Because of extensive tumor invasion of the trachea, tracheostomy was performed under V-V ECMO support. There were no complications arising from the ECMO support in the perioperative period, and the patient is currently undergoing additional postoperative treatment.

We performed surgery under ECMO support for head and neck cancer patients in whom tracheal intubation and tracheotomy under local anesthesia were expected to be challenging due to severe airway narrowing caused by the tumors.

Schwannomas are benign tumors that develop from Schwann cells and can arise in any part of the body. Cervical schwannomas are relatively rare, being particularly rare in children. We report the case of a child with sympathetic schwannoma arising in the parapharyngeal space. The patient was a 13-year-old girl, in whom computed tomographic examination revealed a tumor measuring 70 × 26 mm in size extending from the dorsal right carotid bifurcation to the parapharyngeal space, with heterogeneous internal enhancement. On magnetic resonance imaging, T1-weighted images showed iso- to hypointensity of the lesion, while T2-weighted images showed iso- to hyperintensity of the lesion, with heterogeneous enhancement within the lesion. At operation, the lower edge and dorsal aspect of the tumor was found to be contiguous with the sympathetic chain. After confirming nerve fibers coursing over the tumor, the epineurium was incised at a distant site from the nerve fibers, and intracapsular excision of the tumor was performed. Postoperatively, the patient developed mild Horner’s syndrome (ptosis and constricted pupil on the right side) and incomplete palsy of the mandibular branch of the facial nerve, both of which improved spontaneously within 2 months. There are no clear indications of surgery for cervical schwannoma. Moreover, various treatment options have been reported, including observation without surgery, biopsy without surgery, and surgey using various techniques. In the case of children, considering the patient’s life expectancy and potential of the tumor to grow, there is a high possibility that the tumor will continue to grow, and early surgery may reduce the risk of postoperative complications and avoid the need for highly invasive approaches. In children, it is necessary to consider performing surgery, as the surgical risk and risk of postoperative complications are low.

Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (EBV-LPDs) are characterized by the proliferation of EBV-infected lymphocytes in the body. Although EBV infection is usually asymptomatic and persists lifelong as a latent infection, it is sometimes associated with the development of some types of lymphomas, which are aggressive and respond poorly to chemotherapy. It is thought that aging or immunosuppression (for example, administration of immunosuppressive drugs) may activate dormant EBV-infected B cells, to result in lymphoproliferative disorders.

We report a case of EBV-associated diffuse large B-cell lymphoma (DLBCL) of the pharynx in a 74-year-old woman who initially presented with a sore throat. Physical examination revealed enlargement of the right palatine tonsil and right cervical lymph nodes. As the condition failed to resolve with conservative treatment, biopsies of the right palatine tonsil and a right cervical lymph node were performed. Histopathology revealed just inflammatory changes. While the patient’s condition improved spontaneously over time, she presented again 3 months later with an ulcer in the lingual tonsil. Histopathological examination of a biopsy specimen obtained from the ulcerative lesion again showed only inflammatory changes. Upper gastrointestinal endoscopy was performed considering the possibility of Behçet’s disease, and an ulcerative lesion was detected in the duodenum. Biopsy of this lesion led to the definitive diagnosis of EBV-LPD and EBV-associated DLBCL. Although chemotherapy eventually led to remission, it took over 6 months to arrive at a definitive diagnosis. This case serves to underscore the importance of keeping in mind the possibility of EBV-LPD in patients with a refractory pharyngeal ulcer.

Although penetrating neck injuries can be fatal, they are uncommon in Japan. We report a rare case of a penetrating neck injury.

The patient was a 19-year-old male who presented to our Emergency Department (ED) after having been stabbed in his neck with a kitchen knife. A 2 × 1 cm stab wound was found on his neck. The wound initially hemorrhaged in the ED and was controlled, but rebleeding occurred later, necessitating hemostatic surgery under general anesthesia. Intraoperative exploration revealed injury to the right vertebral vein, which was ligated to achieve hemostasis. The patient had an uneventful recovery and was discharged on POD8.

A PubMed search for articles including the terms “neck stab, surgery, case report” published between 2016 and 2020 yielded 10 relevant reports. All the reported cases showed good recovery. However, in 4 instances, the precise site of injury could not initially be detected, necessitating extra treatment, underscoring the importance of careful management of penetrating neck injuries.

‘Hard signs’, findings that indicate damage to the major blood vessels of the neck, trachea, or esophagus, when present, indicate the need for urgent surgical hemostasis. Even if there are no hard signs, CT scan and/or CT angiography should be considered.

In our case, there were no hard signs, but we assumed that the knife had reached the deep neck based on the finding of emphysema in the upper mediastinum. However, we had not expected injury to the vertebral vein, due to the preconceived notion that injury to this vein located in the deepest area would not occur without injury to other major vessels.

In cases of vascular injury, prompt measures are imperative, as failure of hemostasis could prove fatal. In our case, the exact location of the injury could be determined only after an external incision in the operating room. It is important to establish a medical system that promptly provides the necessary personnel and equipment for surgery for these cases.

Descending necrotizing mediastinitis is a serious disease secondary to inflammation of tissues of the neck, that is often complicated by septic shock. We report a case of descending necrotizing mediastinitis secondary to a cervical abscess, which was successfully treated. The patient was a 67-year-old man with no significant past medical history who was referred to our hospital with a 3-day history of fever, sore throat, and respiratory distress. His vital signs indicated that he was in a shock state at the time of presentation, and CT examination showed an abscess in the left cervical region, with evidence of inflammation extending into the mediastinum. We made the diagnosis of cervical abscess, descending necrotizing mediastinitis, and septic shock, and performed cervical incision and drainage. Postoperatively, the patient was managed in the intensive care unit, however, as he failed to show improvement, we subsequently performed thoracoscopic drainage and mediastinoscopic drainage as well. He improved gradually thereafter, and was weaned from the ventilator on the 44th day of hospitalization. As cultures grew resistant bacteria, long-term antibiotic treatment was required, and the patient was discharged home without sequelae on the 94th day of hospitalization. Descending necrotizing mediastinitis may not only be complicated by septic shock, but also by acute renal failure and acute respiratory distress syndrome, and collaboration among multiple department is recommended for treating these patients.

Intratympanic steroid therapy (ITS) has recently been used as primary or salvage treatment for idiopathic sudden sensorineural hearing loss.

We conducted a retrospective comparison of the efficacy of ITS and systemic steroid therapy (SS) as initial therapy for idiopathic sudden sensorineural hearing loss (ISSHL).

There were a total of 112 patients who received treatment for ISSHL at our hospital (including 44 who received ITS, and 68 who received SS).

Statistical comparison of the background characteristics of the patients showed that the mean age was significantly higher (76 yr. vs. 65 yr; p < 0.0001), the percentage of patients with diabetes mellitus was higher (55% vs. 18%; p < 0.0001), and the rate of prior steroid use was lower (9% vs. 31%; p = 0.0068) in the ITS group as compared with the SS group. The treatment response at the end of 3 weeks of treatment was complete recovery/significant improvement/slight improvement/no change in 11/9/8/16 patients of the ITS group and 32/11/5/20 patients of the SS group; thus, the SS group showed a significantly higher rate of complete recovery than the ITS group (ITS vs. SS, 25% vs. 47%; p = 0.0191). Analysis after propensity score matching also confirmed a higher rate of complete recovery in the SS group than in the ITS group (ITS vs. SS, 22% vs. 48%; p = 0.0461).

Thus, we recommend SS as a primary treatment for ISSHL in patients who are not elderly and/or not at a high risk for complications from SS.