• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.28 no.2
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• pp.71-78
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• 2017

Voice disorder is classified into three categories, structural, neurogenic and functional dysphonia. Neurogenic dysphonia refers to a disruption in the nerves controlling the larynx. Common examples of this include complete or partial vocal cord paralysis, spasmodic dysphonia. Also it occurs as part of an underlying neurologic condition such as Parkinson's disease, myasthenia gravis, Lou Gehrig's disease or disorder of the central nervous system that causes involuntary movement of the vocal folds during voice production. Functional dysphonia is a voice disorder in the absence of structual or neurogenic laryngeal characteristics. A near consensus exist that Muscle tension dysphonia (MTD) is functional voice disorder wherein hyperfunctional laryngeal muscle activity whereas Spasmodic dysphonia (SD) is neurogenic, action-induced focal laryngeal dystonia including several subtype. Both Adductor type spasmodic dysphonia (AdSD) and MTD may be associated with excessive supraglottic contraction and compensation, resulting in a strained voice quality with spastic voice breaks. It makes these two disorders extremely difficult to differentiate based on clinical interpretation alone. Because treatment for AdSD and MTD are quite different, correct diagnosis is important. Clinician should be aware of the specific vocal characteristics of each disease to improve therapeutic outcome.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.10 no.2
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• pp.102-118
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• 1999

In this study, the author developed a new animal model to examine morphological changes and functional recoveries after vertical hemilaryngeal transplantation in the canine. Seven vertical hemilaryngeal transplantations were carried out in the canine. After preparing the host dog removing right sided hemilarynx, hemilarynx of the donor dog was transplanted by hooking up the arteries, veins, nerves and hypopharyngeal mucosa. Especially, recurrent laryngeal nerve was anastomosed at the branch level(anterior and posterior) respectively. After 7 days, for the first evaluation of the transplantation, four out of seven dogs were considered successful. Three dogs survived more than one month, which is the critical period to evaluate the functional recovery after transplantations. After EMG examination, two dogs(#3, #5 dog) showed some functional recoveries. The five-transplanted hemilarynges were sectioned at the arytenoid cartilage region to examine the morphological changes. The results showed that the transplanted hemilarynx appeared normal as control in #5 dog. In addition, #2 dog showed fairly good condition even though died from asphyxia after 9 days out of transplantation. The other. three dogs(#3, #6, #7) showed various levels of atrophy and disappearance of the muscles and cartilages in their larynges. It can be suggested that this model could contribute an advance to preparing human laryngeal transplantation in the future.

• International journal of thyroidology
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• v.11 no.2
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• pp.130-136
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• 2018

Background and Objectives: Intraoperative neural monitoring (IONM) of recurrent laryngeal nerve (RLN) in thyroid surgery has been employed worldwide to identify and preserve the nerve as an adjunct to visual identification. The aims of this study was to evaluate the efficacy of IONM and difficulties in the learning curve. Materials and Methods: We studied 63 patients who underwent thyroidectomy with IONM during last 2 years. The standard IONM procedure was performed using NIM 3.0 or C2 Nerve Monitoring System. Patients were divided into two chronological groups based on the success rate of IONM (33 cases in the early period and 30 cases in the late period), and the outcomes were compared between the two groups. Results: Of 63 patients, 32 underwent total thyroidectomy and 31 thyroid lobectomy. Failure of IONM occurred in 9 cases: 8 cases in the early period and 1 case in the late period. Loss of signal occurred in 8 nerves of 82 nerves at risk. The positive predictive value increased from 16.7% in the early period to 50% in the late period. The mean amplitude of the late period was higher than that of the early period (p<0.001). Conclusion: IONM in thyroid surgery is effective to preserve the RLN and to predict postoperative nerve function. However, failure of IONM and high false positive rate can occur in the learning curve, and the learning curve was about 30 cases based on the results of this study.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.12 no.1
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• pp.46-54
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• 2001

Background and Objectives : Nitric oxide(NO) is a short-lived molecule with messenger and cytotoxic functions in nervous, cardiovascular, and immune systems. Among the three distinct NOS isoforms, the neuronal isoform is expressed in small, discrete neuronal populations of CNS and PNS. Axonal injury in adult animals results in a dramatic NOS up-regulation in many types of central and peripheral neurons which normally lack the enzyme or express it only at very low levels. In previous study, we confirmed the efficacy of PEMS on the early functional recovery in rats with surgically transected and reanastomosed recurrent laryngeal nerve. Therefore, after we obtained functionally recovered rats using PEMS in this study, we studied to evaluate the expression of nNOS through the analysis of the difference between functional recovery group and non-recovery group in the recurrent laryngeal nerve. Materials and Method : Using 84 healthy male Sprague-Dawley rats, transections and primary anastomosis were performed on their left recurrent laryngeal nerves. Rats were then randomly assigned to 2 groups. The rats in group A(n=42) received PEMS by placing them in custom cages equipped with Helm-holz coils(3 hr/day, 5 days/wk, for 12 wk). The rats in group B(n=42) were handled the same way as the group A, except that they did not receive PEMS. Laryngovideoendoscopy was performed before and after surgery and followed up weekly. Laryngeal EMG was obtained in both PCA and TA muscles. Immunohistochemisty staining using monoclonal anti-neuronal nitric oxide synthase(nNOS) antibody was performed to detect nNOS in recurrent laryngeal nerve and nodose ganglion. Results : 20 rats(63%) in group A and 5 rats(17%) in the group B showed recovery of vocal fo1d motion. The number of NOS-positive cells was increased in functionally-recovered rats. NOS-staining intensity was reduced 12 weeks after nerve injury. The difference between PEMS group and non-stimulated group was not found. Conclusion : This study shows that nNOS may exert a beneficial effect on nerve regeneration and functional repair.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.12 no.2
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• pp.126-132
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• 2001

Background and Objectives : Signal traduction through phospholipase C(PLC) participate in the regulation of cell growth and differentiation. Growth factors bind to their receptors and thereby induce tyrosine phophorylation of the phospholipase C-${\gamma}$1(PLC-${\gamma}$1). PLC-${\gamma}$1 is a substrate for several receptor tyrosine kinases and its catalytic activity is increased by tyrosine phosphorylation. Tyrosine kinase phosphorylation of PLC-${\gamma}$1 stimulates PLC activation and cell proliferation. However the signal transduction pathway and the significance of PLC in injured recurrent laryngeal nerve regeneration is unknown. Therefore after we obtained fuctionally recovered rats using PEMF in this study, we attempt to provide some evidence that PLC plays a role in nerve regeneration itself and regeneration related to PEMF through the analysis of the difference between fucntional recovery group and non-recovery group in the recurrent laryngeal nerve. Materials and Method : Using 32 healthy male Sprague-Dawley rats, transections and primary anastomosis were performed on their left recurrent laryngeal nerves. Rats were then randomly assigned to 2 groups. The experimental group(n=16) received PEMS by placing them in custom cages equipped with Helm-holz coils(3hr/day, 5days/wk, for 12wk). The control group(n=16) were handled the same way as the experimental group, except that they did not receive PEMS. Laryngo-videoendoscopy was performed before and after surgery and followed up weekly. Laryngeal EMG was obtained in both PCA and TA muscles. Immunohistochemisty staining and Western blotting analysis using monoclonal antibody was performed to detect PLC-${\gamma}$1 in recurrent laryngeal nerve and nodose ganglion. Results : 10 rats(71%) in experimental group and 4 rats(38%) in the control group showed recovery of vocal fold motion. Functionally-recoverd rats show PLC-${\gamma}$1 positive cells in neuron and ganglion cells after 12 weeks from nerve injury. Conclusion : This study shows that PLC1-${\gamma}$ involved in singnal trasduction pathway in functinal recovery of injured recurrent laryngeal nerve and PEMF enhance the functional recovery by effect on this molecule.

• Korean Journal of Head & Neck Oncology
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• v.23 no.1
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• pp.58-62
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• 2007

Schwannoma is a benign well-encapsulated tumors arising from the sheath of Schwann cell of the peripheral motors, sensory, and cranial nerves, but not from the optic and olfactory nerves. Since it is relatively common in the head and neck region, it should be included in the differential diagnosis of head and neck tumor. However, reports of laryngeal involvement have rarely appeared in the literature. We have experienced a 50-year old woman and 39-year old woman with history of progressive voice change. We recognized a benign mass at the false cord area with the telelaryngoscope and CT. The tumors were successfully removed by transoral CO2 laser resection without tracheotomy.

• Journal of Chest Surgery
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• v.56 no.5
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• pp.336-345
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• 2023

Background: The objective of this study was to demonstrate the safety, efficacy, and feasibility of intraoperative monitoring of the recurrent laryngeal nerves during thoracoscopic and robotic 3-field esophagectomy. Methods: This retrospective analysis details our initial experience using intraoperative nerve monitoring (IONM) during minimally invasive 3-field esophagectomy. Data were obtained from a prospectively maintained database and electronic medical records. The study included all patients who underwent minimally invasive (video-assisted thoracic surgery/robotic) transthoracic esophagectomy with neck anastomosis. The patients were divided into those who underwent IONM during the study period and a historical cohort who underwent 3-field esophagectomy without IONM at the same institution. Appropriate statistical tests were used to compare the 2 groups. Results: Twenty-four patients underwent nerve monitoring during minimally invasive 3-field esophagectomy. Of these, 15 patients underwent thoraco-laparoscopic operation, while 9 received a robot-assisted procedure. In the immediate postoperative period, 8 of 24 patients (33.3%) experienced vocal cord paralysis. Relative to a historical cohort from the same institution, who were treated with surgery without nerve monitoring in the preceding 5 years, a 26% reduction was observed in the nerve paralysis rate (p=0.08). On follow-up, 6 of the 8 patients with vocal cord paralysis reported a return to normal vocal function. Additionally, patients who underwent IONM exhibited a higher nodal yield and a decreased frequency of tracheostomy and bronchoscopy. Conclusion: The use of IONM during minimally invasive 3-field esophagectomy is safe and feasible. This technique has the potential to decrease the incidence of recurrent nerve palsy and increase nodal yield.

• Korean Journal of Head & Neck Oncology
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• v.22 no.2
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• pp.137-141
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• 2006

Purpose : It has been generally accepted that lobectomy is a standard surgical procedure in treatment of benign thyroid nodules. However lobectomy may cause postoperative hypothyroidism. Most of surgeons believe that nodulectomy has its limitation in treatment of thyroid nodules due to recurrence of nodules and presence of cancer. The current study attempts to determine whether nodulectomy is justified in aspects of preservation of thyroid function, risk of recurrence and complications. Methods: Data was collected retrospectively on 74 patients undergoing thyroidectomy(single nodulectomy, n=43;bilateral nodulectomies, n=9;lobectomy with nodulectomy, n=22) for benign thyroid nodules from 1999 to 2004. All patients were evaluated for complication, postoperative thyroid function, and recurrence of benign nodule and cancer were followed by regular ultrasonographic examination for 2-6 years. Results : The pathologic results of 74 patients were nodular hyperplasia(55 patients), Hashimoto's thyroiditis(8 patients), follicular adenoma(7 patients) and papillary carcinoma(4 patients). Average operation time was 30 minutes from skin incision to specimen out. In postoperative follow-up of 70 patients, six cases(8.5%) became mild hypothyroid, and ultrasonographically detected micronodule was also six cases(8.5%). There were no other complications. Conclusion : Thyroid nodulectomy appears to have advantages of relatively few complication and simple procedure with no access to laryngeal nerves. Therefore, it may be one of treatment options in selected cases of benign thyroid nodules.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.27-34
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• 2000

A 20-day-old female Diprosopia in Holstein calf was observsd macroscopically and radiographically. Anterior head duplication(Diprosopia) was observed and all structures caudal to it were normal. She had two muzzles, three eyes, two ears and two tongues. The tongues were joined at their base just posterior and had one hyoid bone. Schistognathia and cleft lips were also observed in the lower jaws. She had an oral cavity, single epiglottis and a laryngeal cavity communicated with one trachea. The cerebral hemispheres were duplicated and fused together in the caudal region. The olfactory and optic nerves were duplicated. The incisive, nasal, pterygoid, parietal, ethmoid bones and vomer were duplicated, respectively. The skull of Diprosopia was shared by an occipital bone. The mandibules, palatines and sphenoid bones were duplicated incompletely. Three orbits and two fontanelles were observed. The medial lacrimal bones and maxillae were duplicated incompletely and fused with each other, respectively. Cleft palates were observed. Medial mandibular mass which was fused together and was duplicated incompletely at the part of its cranial, was shown synchondrosis with the left mandible, but not with the right.