Neuronal re-juvenilization in the nucleus ambiguus after vagal nerve injury.

Nestin is an intermediate filament expressed in immature cells in the CNS including neural stem/progenitor cells, reactive astrocytes and immature neurons in lesser amounts after injury. Nestin expression in the nucleus ambiguus following vagal nerve injury was studied using nestin-EGFP transgenic rats. We confirmed that EGFP immunoreactivity was evident at 6h to 8 days in ipsilateral nucleus ambiguus after nerve transection. Properties of these cells were examined immunohistochemically. These EGFP-immunoreactive cells were immunoreactive for Tuj1 and Hu, and exhibited ChAT activity. However, no immunoreactivity for GFAP or CNPase was observed. In normal development, the level of KCC2 expression is known to increase with maturation of neurons. In our study, decreased KCC2 expression was observed in nestin-EGFP-positive cells within the nucleus ambiguus on the lesioned side compared with the contralateral side. These EGFP-immunoreactive cells were immunonegative for BrdU. This is the first study to demonstrate the expression of a neural stem/progenitor cell-enriched marker, Nestin, in the nucleus ambiguus after vagal nerve injury. The present findings suggest that mature motoneurons are an origin of these Nestin-positive cells, which are induced after injury. Mature neurons in the nucleus ambiguus may thus have the potential to juvenilize after vagal/recurrent laryngeal nerve injury.

Injection laryngoplasty with calcium phosphate cement.

OBJECTIVE: To assess the feasibility of injection laryngoplasty with calcium phosphate cement (CPC), which is an injectable paste, self-hardening, and which recrystallizes to calcium hydroxylapatite after injection. STUDY DESIGN: A case series with planned data collection. METHODS: Fifty-six patients with unilateral vocal fold paralysis, who received injection laryngoplasty with CPC between August 2003 and August 2007 with a minimum follow-up period of six months, were enrolled in this study. Volumetric and migration analysis for injected CPC were performed using CT after surgery. Vocal function was also assessed by GRBAS subjective voice assessment scale and maximum phonation time (MPT), acoustic analysis including period perturbation quotient (PPQ), amplitude perturbation period (APQ), and noise-to-harmonics ratio (NHR). RESULTS: No remarkable migration or absorption of injected CPC was observed on CT up to two years after surgery. The average remaining volume of CPC was 87.8% +/- 5.3% two years after injection compared to immediately after injection. Significant improvements in GRBAS scales, MPT, PPQ, APQ, and NHR were observed postoperatively. No adverse effects were observed. CONCLUSIONS: Our clinical experience revealed that CPC was safe, nonabsorbable, and effective. Injection laryngoplasty with CPC may be a useful option in the treatment of glottic insufficiency.

[Clinical experience with silicon pharyngeal tube for pharyngocutaneous fistula and cervical esophagus stenosis].

Total laryngectomy or laryngopharyngectomy are commonly performed for the treatment of laryngeal cancer or hypopharyngeal cancer. However pharyngocutaneous fistula and cervical esophageal stenosis have been reported as postoperative complications of these procedures. We used a silicon pharyngeal tube in cases that developed pharyngocutaneous fistula and cervical esophageal stenosis. The pharyngeal tube was useful for controlling aspiration pneumonia and for starting oral feeding in a case of pharyngocutaneous fistula after a total laryngectomy. It was also helpful for starting oral feeding in a case with cervical esophageal stenosis after total laryngopharyngectomy and free jejunum interposition. This patient was able to maintain a good quality of life until re-operation. Adverse effects from the insertion of the tube included a foreign body sensation and pharyngeal pain that was tolerable with the use of NSAIDs for a short time. Silicon pharyngeal tubes are useful for the treatment of pharyngocutaneous fistula and cervical esophageal stenosis.

Suitability of calcium phosphate cement for injection laryngoplasty in rabbits.

Calcium phosphate cement (CPC) consists of powder and liquid, which become an injectable paste after mixing, self-hardening and recrystallizing to calcium hydroxylapatite (CaHA) after injection into a living body. In this study, we investigated the suitability of CPC as an injectable material for injection laryngoplasty using rabbits. All rabbits underwent left recurrent laryngeal nerve section and injection laryngoplasty with CPC. At 7 days, scanning electron microscopic findings revealed that complete recrystallization from CPC to CaHA was achieved in the larynx. At 1, 3, and 6 months, injected CPC stayed in the paraglottic space and did not migrate, and the average remaining CPC volume percentage was 91.7%. Focal foreign body reaction to injected CPC was almost the same as that of autologous fat for all time periods observed. These results indicated that CPC appears to be biocompatible, nonabsorbable, nonmigratory, and suitable for injection laryngoplasty.

Aphonia and dysphagia after gastrectomy.

A 67-year-old male was referred to our otolaryngological clinic because of aphonia and dysphagia. His voice was breathy and he could not even swallow saliva following a total gastrectomy for gastric carcinoma performed 2 weeks previously. Laryngeal fiberscopy revealed major glottal incompetence when he tried to phonate. However, both vocal folds abducted over the full range during inhalation. The patient could not swallow saliva because of a huge glottal chink, even during phonation. Based on these findings, he was diagnosed as having bilateral incomplete cricoarytenoid dislocation after intubation. The patient underwent speech therapy; within 1 min his vocal fold movement recovered dramatically and he was able to phonate and swallow. There have been few case reports of bilateral cricoarytenoid dislocation, and no effective rehabilitation has been reported. We believe that our method of vocal rehabilitation serves as a useful reference for physicians and surgeons worldwide.

High-quality video recording and monitoring system for endoscopes.

We have developed a new recording system for endoscope images with the popular mini digital video (mini DV) camera. A special adaptor screws onto the lens top, and either a flexible or rigid endoscope can be attached to the camera. Using this system, we can monitor not only the endoscopic images but also the patient's condition. Satisfactory images can be obtained even with the finest fiberscope. Nevertheless, our new system costs only USD 1,000. Therefore, the system is both cost-effective and useful for the outpatient clinic or casual setting or for house calls for the purpose of patient education.