It has been almost a half of century since the technique of laryngomicrosurgery was developed. This paper describes and discusses the essence of the technique as derived from the fundamental studies concerning vocal fold function. These studies indicate that the vocal fold membrane must be flexible for excellent wave motion in order to produce excellent sound. Unnecessary and frequent operative manipulation will affect wound healing, resulting in scar formation. The key words of importance to keep top of mind while performing laryngomicrosurgery are as follows : simple manipulation of the operation, maintenance of the flexibility of the vocal fold membrane, excellent wave motion, and excellent sound production.

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Acute epiglottitis, as well as airway management of this malady in adults, can rapidly deteriorate into an airway obstruction. This potential emergency demands prompt evaluation of the epiglottis with an emphasis on vigilant and proficient attention to airway management. During the examination, the patient should be in a sitting position while under intense observation in preparation for tracheal intubation at any time. For patients affected by respiratory distress, ventilation with 100% O₂ and urgent intubation are needed. Choose 1 or 2 sizes smaller than the usual tube size for intubation. Oral intubation along with administration of a sedative and muscle relaxant is comparatively safe and easy. However, in cases where : 1) difficulty in airway establishment is anticipated, 2) SpO₂ does not elevate in spite of enough O₂ supply, or 3) the patient is already in shock, a sedative or muscle relaxant would precipitate respiratory arrest. In such cases, consider whether oral intubation without a sedative or muscle relaxant or nasal intubation with an endoscope can be performed. Nasal intubation with an endoscope in a sitting position might be effective. For the patient in agony or with difficulty in opening their mouth, intubate after administrating a little amount of sedative while monitoring blood pressure and SpO₂. If it is difficult to establish their airway rapidly, administrate vecuronium and choose oral tracheal intubation while being prepared for implementing an emergent tracheotomy, or a cricothyroidotomy; either needle or surgical. If unable to intubate successfully, ventilate with the bag-valve-mask technique with 100% O₂ as far as possible, then provide an emergent tracheotomy, needle or surgical cricothyroidotomy immediately.

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This article presents the post-mortem findings of acute epiglottitis in adults. Acute epiglottitis is a serious disease because of its potential for sudden fatal obstruction in a previously healthy individual. We reported on a case of adult epiglottitis who could not be resuscitated. The patient had complained dyspnea. An upper airway obstruction occurred within an hour after an intravenous steroid injection. The patient underwent emergent tracheotomy. The patient died after 17days after the tracheotomy. The autopsy revealed that inflamed cells had infiltrated around an epiglottic cyst. This evidence indicated that an epiglottic cyst is one of the risk factors which can cause or make worse acute epiglottitis.

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This study reports on the clinical application of gene therapy and oral administration of T-588 for laryngeal paralysis. The therapeutic effects of gene therapy in rat laryngeal paralysis studies have been demonstrated. Now, the development of a safe gene delivery system is the essential issue for realizing clinical application. Currently, we are investigating two gene delivery systems, Sendai virus vector and electroporation, for possible clinical use. Sendai virus (SeV), a negative strand RNA virus has no known pathogenicity to humans, and its strict cytoplasmic life cycle in mammalian cells may guarantee substantial safety for human gene therapy. We scrutinized the applicability and efficacy of Sev vectors expressing either LacZ or IGF-I in gene transfer into skeletal muscle tissue. Seven days after the intramuscular injection of LacZ/SeV, a large number of X-gal labeled myofibers were observed in the leg muscle of a rat. The introduction of IGF-I/SeV showed a significant increase in regenerating and split myofibers indicative of hypertrophy, and also an increase in the total number of myofibers. We also investigated the applicability of electroporation for gene transfer into rabbit laryngeal muscle tissue, using plasmid DNA expressing GEP. The laryngeal muscle were injected with the plasmid DNA and electric pulses were delivered. Five days after gene transfer, a large number of muscle fibers expressing GEP were observed. These results indicate that either SeV or electroporation may be used as a gene delivery system for human gene therapy for laryngeal paralysis. In addition to gene therapy, we are investigating whether orally administered T-588, a neuroprotective agent, can be applied as a novel drug therapy for laryngeal paralysis. T-588 showed neuroprotective effects in a rat vagal nerve avulsion model as well as improvement in neurofunction in a rat recurrent nerve-injured model. These results support the applicability of T-588 for the treatment of laryngeal paralysis.

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Airway reconstruction after resection of malignancies or stenotic inflammatory lesions after traumatic injury is one of the most difficult procedures. To provide functional regeneration of the airway, we used in situ Tissue Engineering technique. As the tissue scaffold, Marlex mesh reinforced with polypropylene rings covered by a collagen sponge was developed. This scaffold material was implanted in animal models. After the safety and the utility were confirmed in the animal studies, the current regenerative technique was applied in human clinical cases with good results. However the growth speed of the tracheal epithelium over the artificial material was slow. To solve this problem, we tried to develop a hybrid material with which to cover the epithelium of the trachea. In this paper we report the basic research results of tissue engineering for the airway tract to date and of its clinical application. Furthermore, we report our current development of the hybrid artificial material.

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We reviewed twenty-four patients (22 males and 2 females, with an average age of 66 years) afflicted by supraglottic carcinoma with tumor extension to the base of the tongue. These patients underwent curative treatment between 1977 and 2003 at the Kurume University Hospital.
Total laryngectomies were perfomed in 18 cases and partial laryngectomies were perfomed in 6 cases. The disease-specific 5-year survival rate was 77%. The 3-year local control rate was 88%. Local recurrence was recognized in 3 cases. Histopathological examination of these cases revealed tumor invasion into the preepiglottic space. Six patients died of the primary disease (3 by locoregional, 1 by lymph node and 2 by distant metastasis occurrences).
The retrospective study indicates that enough resection by a total laryngectomy is necessary for cases with tumor invasion into the pre-epiglottic space while a partial laryngectomy should be applied for supraglottic carcinoma without invasion into the pre-epiglottic space.

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Post-tracheostomy management of tracheal granulation is discussed in this article. Two cases of a tracheal granulation were successfully and conservatively treated with some useful tools in a novel way. A 2-year-old girl that had a tracheostomy with a 3.5mm tube suffered from an enlarged tracheal granulation. It was flattened out using a 3.5mm endotracheal tube and a stabilizer originally designed for ureteric, biliary and gastric catheters on the abdominal wall. This stabilizer allowed us to secure an endotracheal tube at the tracheostoma to avoid inadvertent decannulation or incorrect intubation. A 20-year-old woman with muscle dystrophy developed tracheal granulation after having a tracheostomy. Although she required 24-hour ventilation support, she wanted to speak. The granulation was initially resolved by using a long tracheostomy tube that did not allow her to speak. This was replaced with a speech tracheostomy tube (Merasofit clear CF) that is usually prohibited when using the ventilator because of excessive leakage through conduits. Merasofit clear CF is a kind of speech tracheostomy tube, which has a mobile flange to prevent tracheal granulation as well as smaller expiration conduits than other conventional tubes. It was found that this speech tracheostomy tube is compatible with ventilation, preserves oral communication and allows safe alimentation by mouth while preventing recurrence of granulation.

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A case of a partially swallowed fish bone that migrated into the hypopharyngeal mucosa is reported. A 57-year-old female who had a pain after eating fish is presented. The migrated fish bone was easily detected in her hypopharyngeal mucosa, so that the fish bone was carefully removed. Eight days after removal, she had a sharp pain in her pharynx. A CT scan was performed immediately and the CT suggested that some of the fish bone remained in her hypopharyngeal mucosa. Subsequently, direct laryngoscopy with the patient under general anesthesia was performed and the remaining fish bone was extracted.
In many cases, impacted fish bones are readily detected and removed, so a radiological examination is not necessary to provide a diagnosis; however, a CT scan is useful to identify a migrated fish bone that cannot be seen directly.

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Recurrent nerve paralysis induced by flexible fiberesophagoscopy is discussed in this article. An 82-year-old male complained of breathy hoarseness that persisted 4 weeks after an emergency flexible esophagoscopic examination. A fiberscope with on outside diameter of 9 mm was utilized and aspirin was administered for atrial fibrillation. The laryngeal fiberscopic examination revealed motility disturbance of the vocal cord on the right side and incompetent glottal closure. Abnormal mobility of the vocal fold and upper structure of the arytenoids cartilage on the affected side has been observed in cases with arytenoids cartilage dislocation. In this case, however, under videofluorographic examination of the larynx during repetitive production of phoneme/he/, such abnormal mobility was not observed. A computed tomography scan revealed a hematoma around the cricoarytenoid joint, swelling of the posterior cricoarytenoid muscle, and anterior osteophyte from the 5 to 7th cervical vertebrae which protruded mainly on the right side. In addition, an electromyographic examination of the thyroarytenoid muscle showed neurogenic pattern change. We thus concluded that his voice disorder was caused by recurrent nerve paralysis induced by flexible fiberesophagoscopy. Four weeks following these examinations, the recurrent nerve paralysis and his voice were completely recovered.

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We reported on two cases of associated laryngeal paralysis due to varicella-zoster virus (VZV) infection. One case, a 64-year-old woman, complained of headache, hoarseness and dysphasia. She had no skin rash. Physical examinations revealed paralyses of the right soft palate and right laryngeal region. The serum antibody (IgM) for VZV was markedly increased. She was diagnosed as having unilateral paralysis of the IX and X cranial nerves caused by VZV. She was treated with an intravenous steroid, but paralysis of the IX and X cranial nerves persisted.
The other case, a 58-year-old man, was admitted to our hospital complaining of otalgia on the right side, a rush on the right auricle, hoarseness, dysphasia and facial palsy on the right side. Herpetic vesicles were present on the right arytenoid. The serum antibody titer for VZV was elevated. He was diagnosed as having unilateral paralysis of the VII, IX and X cranial nerves caused by VZV. He was treated with an intravenous acyclovir and steroid. After treatment he did not have any residual signs of the disease.
In cases of unilateral cranial nerve palsy, herpes zoster should be considered.

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In the head and neck region, VZV reactivation is often associated with cranial nerve paralysis, as represented by Ramsay Hunt syndrome. Vagus and glossopharyngeal nerves are also often impaired by VZV reactivation. Most reported cases present with other cranial nerve paralysis, and there are few case reports of isolated nerve paralysis of lower cranial nerves. Although early administration of anti-VZV agents are well known to be very effective, early diagnosis of pharyngolaryngeal VZV infection are not always easy. We present two cases of isolated vagus nerve and glossopharyngeal nerve paralysis caused by VZV reactivation. They were diagnosed by precise endoscopic examination and direct immunofluorescence staining by a monoclonal antibody specific for VZV on the samples from the pharyngolaryngeal mucosal lesions.

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