Satoru Miyamaru

Effects of Long-Term Denervation on the Rat Thyroarytenoid Muscle†

Objectives/Hypothesis: To determine the effects of long‐term denervation on the rat thyroarytenoid (TA) muscle and neuromuscular junctions.

Nerve-muscle pedicle implantation facilitates re-innervation of long-term denervated thyroarytenoid muscle in rats

Conclusions: Nerve-muscle pedicle (NMP) implantation was effective in the recovery from atrophic changes in long-term denervated thyroarytenoid (TA) muscle. Re-innervation occurred via the transferred nerve. However, the effectiveness of the NMP method may decline with increasing duration of denervation. Objectives: To evaluate the effects of NMP implantation on long-term denervated rat TA muscle. Materials and methods: Wistar rats (n=105) were divided into two groups in which the left recurrent laryngeal nerve (RLN) was transected without (DNV group) or with (NMP group) subsequent NMP implantation, and subgroups of each group were formed depending on the period after RLN transection (immediate to 48 weeks). In the DNV subgroups, we histologically assessed the area of muscle and the number of neuromuscular junctions. In the NMP subgroups, we performed electromyographic, videolaryngoscopic, and histologic assessments. The muscle area and muscle action potentials were evaluated by comparing the treated and untreated sides. The ratio of the number of nerve terminals to that of acetylcholine receptors was also assessed. Results: The TA muscle area was significantly larger in most of the NMP subgroups compared with the DNV subgroups. Muscle action potentials were present in all NMP animals. All histologic and physiologic assessments revealed degradation as the denervation period in the five NMP subgroups.

Modulation of MyoD- and Ki-67-positive satellite cells in the short-term denervated rat thyroarytenoid muscle

Objectives: To evaluate the effects of short‐term denervation on the kinetics of satellite cells (SCs) and myocytes in the rat thyroarytenoid (TA) muscle using immunohistochemistry for a myogenic regulatory factor, MyoD, and a cell proliferation marker, Ki‐67.

A postmeningitic cochlear implant patient who was postoperatively diagnosed as having X-linked agammaglobulinemia

X-linked agammaglobulinemia (XLA) is caused by a mutation in the Bruton tyrosine kinase, leading to an arrest in B cell development. Consequently, patients with XLA show significant decreases in gammaglobulin. Here, we describe a child with postmeningitic deafness and XLA who underwent a cochlear implantation. His psychomotor development had been normal and his congenital immunodeficiency was noticed only postoperatively. Immunoglobulin replacement treatment was started, but he still suffered repeated infections. Eventually, his cochlear implant was removed. A preoperative check of immunological status might be advisable in postmeningitic patients undergoing cochlear implantation to reduce the risk of postoperative infectious complications.

Effects of nerve-muscle pedicle on immobile rat vocal folds in the presence of partial innervation

Objectives: We investigated whether implantation of an ansa cervicalis nerve (ACN)–muscle pedicle into the thyroarytenoid (TA) muscle is efficacious in the presence of partial recurrent laryngeal nerve (RLN) innervation. Methods: We studied a total of 36 rats. Twelve of the rats served as positive and negative control animals. In the remaining 24 rats, the left RLN was transected, a 1-mm piece of nerve was removed, and the stumps were abutted in silicone tubes (STs), inducing partial RLN regeneration. Twelve of the ST-treated rats underwent this procedure alone, and the other 12 rats had a nerve-muscle pedicle (NMP) implanted into the left TA muscle 5 weeks after ST treatment. At 15 weeks, reinnervation was assessed by histologic evaluation of the TA muscle and by electromyography with stimulation of the RLNs and ACNs. Results: The muscle area, the number of nerve terminals, the number of acetylcholine receptors, and the ratio of nerve terminals to acetylcholine receptors were significantly greater (p < 0.05) in the NMP group than in the ST group. Electromyography elicited TA muscle compound action potentials upon stimulation of the RLNs and ACNs. Conclusions: In rats, NMP implantation is efficacious for reducing atrophic changes in the TA muscle in the presence of partial RLN innervation.

Laryngeal chondrosarcoma diagnosed by core-needle biopsy

We report a case of chondrosarcoma of the larynx, diagnosed by a percutaneous core-needle biopsy (CNB). Cartilaginous tumors of the larynx are usually diagnosed by biopsy with direct laryngomicroscopy under general anesthesia. However, patients find it difficult to undergo a biopsy under general anesthesia, for physical, economic, and social reasons. Instead, we can readily detect and sample tumors of the larynx using ultrasound under local anesthesia with reduced stress. Concerning needle-puncture biopsies, including fine-needle aspiration cytology (FNAC) and CNB, some studies have reported needle track dissemination, a possible complication in patients with malignant tumors. Thus, in the head and neck region, we generally use FNAC for biopsies, not CNB. However, it can be difficult to diagnose bone tumors by cytology alone. Regarding primary bone tumors, only one study has reported needle track dissemination by CNB, in osteosarcoma of the femur. Additionally, this complication has not been reported before with chondrosarcoma anywhere in the body. To our knowledge, this is the first report concerning chondrosarcoma of the larynx diagnosed by percutaneous CNB. We recommend CNB as a useful and safe diagnostic technique for primary bone tumors in the head and neck region.

Does Subepithelial Hemorrhage Cause Persistence of Laryngeal Granuloma

Objectives: To determine the incidence of black spots after resolution of laryngeal granuloma (LG), to compare the disease duration from the beginning of treatment to resolution between patients with and without black spots, and to assess the histologic findings of LG in resected or biopsied specimens.

Changes in respiratory function after thyroplastic surgery.

Conclusions. A certain degree of subclinical extrathoracic airway compromise may ensue after thyroplastic surgery, although none of the patients reported the presence of dyspneic symptoms in their normal daily lives. Objectives: To determine the effects of thyroplastic surgery on respiratory function and compare them with the improvement of vocal function. Patients and methods: The study included 53 patients; 7 had type I thyroplasty (type I), 9 had arytenoid adduction (AA), 10 had AA with type I, and 27 had AA with neuromuscular pedicle flap implantation (NMP). Phonatory and respiratory functions were measured preoperatively and postoperatively. The presence of dyspnea during daily activities was determined postoperatively. Results: The difference between the pre- and postoperative values was statistically significant in five comparisons. Forced expiratory volume in 1 s/forced expiratory volume (FEV1%) in the AA with type I group, FEV1/peak expiratory flow rate (PEFR) in the AA group, and PEFR in the three groups (type I, AA, and AA with NMP). Forty-six patients associated with AA were combined for statistical analysis. The differences were statistically significant for FEV1%, PEFR, and FEV1/PEFR. Changes in maximum phonation time (MPT) were found to have a significant correlation with changes in FEV1/PEFR. All the patients denied episodes of dyspnea during their normal daily activities.

Potential treatment for vocal fold scar with pirfenidone: Pirfenidone for Vocal Fold Scar

Pirfenidone (PFD) is a strong antifibrotic agent that has been clinically approved in Japan for idiopathic pulmonary fibrosis. We examined the antifibrotic effects of PFD on fibroblasts isolated from scarred vocal folds (VFs) of ferrets in vitro.

Nerve-muscle pedicle implantation in the denervated thyroarytenoid muscle of aged rats

Abstract Conclusion: Nerve-muscle pedicle (NMP) implantation was effective in the recovery of atrophic changes in the denervated thyroarytenoid (TA) muscle in aged rats. Objectives: To evaluate the effects of NMP implantation on the denervated TA muscle in aged rats. Methods: Wistar rats aged 20 months and 8 weeks were respectively divided into two groups in which the left recurrent laryngeal nerve (RLN) was transected without (aged/young DNV group) or with (aged/young NMP group) NMP implantation. The aged DNV and NMP groups were further divided into two subgroups, based on the period after RLN transection (10 or 20 weeks). In the DNV groups, we assessed the area of muscle and the number of neuromuscular junctions (NMJs) histologically. In the NMP groups, we performed electromyography and histological assessments. For electromyography, we stimulated the transferred nerve and evaluated the muscle action potentials (MAPs) of the TA muscle. Results: The muscle areas in the aged NMP groups were significantly larger than those in the aged DNV groups. More NMJs were found in aged NMP groups compared with aged DNV groups. MAPs were seen in all NMP animals. No significant differences were observed between the aged and young NMP groups in histological and physiological assessments.