Application of an Intraoperative Neuromonitoring System Using a Surface Pressure Sensor in Parotid Surgery: A Rabbit Model Study

Objectives@#. Facial nerve monitoring (FNM) can be used to identify the facial nerve, to obtain information regarding its course, and to evaluate its status during parotidectomy. However, there has been disagreement regarding the efficacy of FNM in reducing the incidence of facial nerve palsy during parotid surgery. Therefore, instead of using electromyography (EMG) to identify the location and state of the facial nerve, we applied an intraoperative neuromonitoring (IONM) system using a surface pressure sensor to detect facial muscle twitching. The objective of this study was to investigate the feasibility of using the IONM system with a surface pressure sensor to detect facial muscle twitching during parotidectomy. @*Methods@#. We evaluated the stimulus thresholds for the detection of muscle twitching in the orbicularis oris and orbicularis oculi, as well as the amplitude and latency of EMG and the surface pressure sensor in 13 facial nerves of seven rabbits, using the same stimulus intensity. @*Results@#. The surface pressure sensor detected muscle twitching in the orbicularis oris and orbicularis oculi in response to a stimulation of 0.1 mA in all 13 facial nerves. The stimulus threshold did not differ between the surface pressure sensor and EMG. @*Conclusion@#. The application of IONM using a surface pressure sensor during parotidectomy is noninvasive, reliable, and feasible. Therefore, the IONM system with a surface pressure sensor to measure facial muscle twitching may be an alternative to EMG for verifying the status of the facial nerve.

Change of Extracellular Matrix of Human Vocal Fold Fibroblasts by Vibratory Stimulation

Background and Objectives@#During speech, the vocal folds oscillate at frequencies ranging from 100–200 Hz with amplitudes of a few millimeters. Mechanical stimulation is an essential factor which affects metabolism of human vocal folds. The effect of mechanical vibration on the cellular response in the human vocal fold fibroblasts cells (hVFFs) was evaluated.Materials and Method We created a culture systemic device capable of generating vibratory stimulations at human phonation frequencies. To establish optimal cell culture condition, cellular proliferation and viability assay was examined. Quantitative real time polymerase chain reaction was used to assess extracellular matrix (ECM) related and growth factors expression on response to changes in vibratory frequency and amplitude. Western blot was used to investigate ECM and inflammation-related transcription factor activation and its related cellular signaling transduction pathway. @*Results@#The cell viability was stable with vibratory stimulation within 24 h. A statistically significant increase of ECM genes (collagen type I alpha 1 and collagen type I alpha 2) and growth factor [transforming growth factor β1 (TGF-β1) and fibroblast growth factor 1 (FGF-1)] observe under the experimental conditions. Vibratory stimulation induced transcriptional activation of NF-κB by phosphorylation of p65 subunit through cellular Mitogen-activated protein kinases activation by extracellular signal regulated kinase and p38 mitogen-activated protein kinases (MAPKs) phosphorylation on hVFFs. @*Conclusion@#This study confirmed enhancing synthesis of collagen, TGF-β1 and FGF was testified by vibratory stimulation on hVFFs. This mechanism is thought to be due to the activation of NF-κB and MAPKs. Taken together, these results demonstrate that vibratory bioreactor may be a suitable alternative to hVFFs for studying vocal folds cellular response to vibratory vocalization.

Change of Extracellular Matrix of Human Vocal Fold Fibroblasts by Vibratory Stimulation

Background and Objectives@#During speech, the vocal folds oscillate at frequencies ranging from 100–200 Hz with amplitudes of a few millimeters. Mechanical stimulation is an essential factor which affects metabolism of human vocal folds. The effect of mechanical vibration on the cellular response in the human vocal fold fibroblasts cells (hVFFs) was evaluated.Materials and Method We created a culture systemic device capable of generating vibratory stimulations at human phonation frequencies. To establish optimal cell culture condition, cellular proliferation and viability assay was examined. Quantitative real time polymerase chain reaction was used to assess extracellular matrix (ECM) related and growth factors expression on response to changes in vibratory frequency and amplitude. Western blot was used to investigate ECM and inflammation-related transcription factor activation and its related cellular signaling transduction pathway. @*Results@#The cell viability was stable with vibratory stimulation within 24 h. A statistically significant increase of ECM genes (collagen type I alpha 1 and collagen type I alpha 2) and growth factor [transforming growth factor β1 (TGF-β1) and fibroblast growth factor 1 (FGF-1)] observe under the experimental conditions. Vibratory stimulation induced transcriptional activation of NF-κB by phosphorylation of p65 subunit through cellular Mitogen-activated protein kinases activation by extracellular signal regulated kinase and p38 mitogen-activated protein kinases (MAPKs) phosphorylation on hVFFs. @*Conclusion@#This study confirmed enhancing synthesis of collagen, TGF-β1 and FGF was testified by vibratory stimulation on hVFFs. This mechanism is thought to be due to the activation of NF-κB and MAPKs. Taken together, these results demonstrate that vibratory bioreactor may be a suitable alternative to hVFFs for studying vocal folds cellular response to vibratory vocalization.

Histologic Analysis of Vocal Folds in Aging Rats

Background and Objectives@#Presbyphonia is characterized by hoarse, breathy, weak vocal intensity. Extracellular matrix (ECM) in lamina propria (LP) of the vocal folds play an important role in voice production, and change of ECM according to the aging leads to the presbyphonia. The aim of this study was to investigate the histologic analysis of aging vocal fold of rat.Materials and Method Six and twenty two months old Sprague-Dawley rats (n=8, each group) were used and classified into young (six months old rats) and old (twenty two months old rats) group. Histologic analysis and immunohistochemical staining for ECM of LP were performed. @*Results@#Overall cellular density was significantly decreased in old rat group. Elastin fibers of LP were significantly decreased in old rat group. Type I collagen was significantly increased in old rat group. Type III collagen did not show significant difference. Hyaluronic acids did not show significant difference in Alcian blue staining and immunohistochemical staining. @*Conclusion@#Decreased general cellular density and elastin fiber and increased type I collagen were observed in the LP of vocal folds of aging rats. These ECM changes might to contribute the aging voice.

Optimal Neck Dissection Extent for Metastatic Lymph Nodes in Papillary Thyroid Cancer

Papillary thyroid cancer (PTC) has a good prognosis, but the frequency of regional lymph node metastasis is reported to be up to 90%. In most patients with PTC, nodal metastasis occurs in a stepwise fashion, with metastasis beginning in the central cervical compartment, continuing to the ipsilateral cervical compartment. There are many controversies about the necessity of prophylactic central neck dissection (CND) and extent of therapeutic CND for lymph node metastasis. Ipsilateral CND with intraoperative frozen biopsy in PTC is a very sensitive and useful tool for the evaluation of nodal status in the central compartment. The right upper para-esophageal lymph nodes should be removed during dissection in patients with right paratracheal lymph node metastasis. Prophylactic lateral neck dissection (LND) is not recommended, and optimal extent of therapeutic LND is still controversial. Further studies on factors and clinical implications related to suprasternal lymph node metastasis are needed.

Application of Novel Intraoperative Neuromonitoring System Using an Endotracheal Tube With Pressure Sensor during Thyroid Surgery: A Porcine Model Study

Objectives@#. The loss of signal during intraoperative neuromonitoring (IONM) using electromyography (EMG) in thyroidectomy is one of the biggest problems. We have developed a novel IONM system with an endotracheal tube (ETT) with an attached pressure sensor instead of EMG to detect laryngeal twitching. The aim of the present study was to investigate the feasibility and reliability of this novel IONM system using an ETT with pressure sensor during thyroidectomy in a porcine model. @*Methods@#. We developed an ETT-attached pressure sensor that uses the piezoelectric effect to measure laryngeal muscle twitching. Stimulus thresholds, amplitude, and latency of laryngeal twitching evaluated using the pressure sensor were compared to those measured using transcartilage needle EMG. The measured amplitude changes by EMG and the pressure sensor during recurrent laryngeal nerve (RLN) traction injury were compared. @*Results@#. No significant differences in stimulus threshold intensity between EMG and the pressure sensor were observed. The EMG amplitude detected at 0.3 mA, increased with increasing stimulus intensity. When the stimulus was more than 1.0 mA, the amplitude showed a plateau. In a RLN traction injury experiment, the EMG amplitude did not recover even 20 minutes after stopping RLN traction. However, the pressure sensor showed a mostly recovery. @*Conclusion@#. The change in amplitude due to stimulation of the pressure sensor showed a pattern similar to EMG. Pressure sensors can be feasibly and reliably used for RLN traction injury prediction, RLN identification, and preservation through the detection of laryngeal muscle twitching. Our novel IONM system that uses an ETT with an attached pressure sensor to measure the change of surface pressure can be an alternative to EMG in the future.

Histologic Analysis of Vocal Folds in Aging Rats

Background and Objectives@#Presbyphonia is characterized by hoarse, breathy, weak vocal intensity. Extracellular matrix (ECM) in lamina propria (LP) of the vocal folds play an important role in voice production, and change of ECM according to the aging leads to the presbyphonia. The aim of this study was to investigate the histologic analysis of aging vocal fold of rat.Materials and Method Six and twenty two months old Sprague-Dawley rats (n=8, each group) were used and classified into young (six months old rats) and old (twenty two months old rats) group. Histologic analysis and immunohistochemical staining for ECM of LP were performed. @*Results@#Overall cellular density was significantly decreased in old rat group. Elastin fibers of LP were significantly decreased in old rat group. Type I collagen was significantly increased in old rat group. Type III collagen did not show significant difference. Hyaluronic acids did not show significant difference in Alcian blue staining and immunohistochemical staining. @*Conclusion@#Decreased general cellular density and elastin fiber and increased type I collagen were observed in the LP of vocal folds of aging rats. These ECM changes might to contribute the aging voice.

A Case of Mucoepidermoid Carcinoma Mixed with Osteosarcoma of the Parotid Gland Extending to the Parapharyngeal Space / 대한이비인후과학회지

Carcinosarcomas, also known as true malignant mixed tumors, are rare tumors of the salivary gland and are composed of both malignant epithelial and malignant mesenchymal elements. They may occur in pre-existing pleomorphic adenomas or arise de novo. Here we report the first case of carcinosarcoma of the parotid gland composed of mucoepidermoid carcinoma and osteosarcoma. The tumor had originated from the parotid gland and extended into the parapharyngeal space. To the best of our knowledge, there have been no reports on mucoepidermoid carcinoma mixed with osteosarcoma ex pleomorphic adenoma in the parotid gland.

Development of a Novel Intraoperative Neuromonitoring System Using an Accelerometer Sensor in Thyroid Surgery: A Porcine Model Study

OBJECTIVES: The sensitivity and positive predictive value of widely used intraoperative neuromonitoring (IONM) using electromyography (EMG) of the vocalis muscle in thyroid surgery are controversial. Thus, we developed a novel IONM system with an accelerometer sensor that uses the piezoelectric effect instead of EMG to detect laryngeal twitching. The objective of this study was to evaluate the feasibility and safety of this novel IONM system during thyroid surgery in a porcine model. METHODS: We developed an accelerometer sensor that uses the piezoelectric effect to measure laryngeal twitching in three dimensions. This novel accelerometer sensor was placed in the anterior neck skin (transcutaneous) or postcricoid area. Stimulus thresholds, amplitude, and latency of laryngeal twitching measured using the accelerometer sensor were compared to those measured through EMG of the vocalis muscle. RESULTS: The amplitudes of the accelerometer sensor at the anterior neck and postcricoid area were significantly lower than those of EMG because of differences in the measurement method used to evaluate laryngeal movement. However, no significant differences in stimulus thresholds between the EMG endotracheal tube and transcutaneous or postcricoid accelerometer sensors were observed. CONCLUSION: Accelerometer sensors located at the anterior neck or postcricoid area were able to identify laryngeal twitching. The stimulus intensity measured with these sensors was equivalent to that from conventional vocalis EMG. Our novel IONM system with an accelerometer sensor that checks changes in surface acceleration can be an alternative to EMG of the vocalis muscle for IONM in the future.

A Case of Mucoepidermoid Carcinoma Mixed with Osteosarcoma of the Parotid Gland Extending to the Parapharyngeal Space / 대한이비인후과학회지

Carcinosarcomas, also known as true malignant mixed tumors, are rare tumors of the salivary gland and are composed of both malignant epithelial and malignant mesenchymal elements. They may occur in pre-existing pleomorphic adenomas or arise de novo. Here we report the first case of carcinosarcoma of the parotid gland composed of mucoepidermoid carcinoma and osteosarcoma. The tumor had originated from the parotid gland and extended into the parapharyngeal space. To the best of our knowledge, there have been no reports on mucoepidermoid carcinoma mixed with osteosarcoma ex pleomorphic adenoma in the parotid gland.

Development of Simplified Version of Korean-Type Tinnitus Handicap Inventory / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The Tinnitus Handicap Inventory (THI) is a useful measure to evaluate the tinnitus and to quantify the functional and psychosocial consequences of tinnitus. However, it can be difficult for patients to understand the items of questionnaire and may take 10 to 15 minutes for them to complete the questionnaire, which can be problematic. The objective of this study is to develop a simplified version of the Korean type Tinnitus Handicap Inventory (THIS). SUBJECTS AND METHOD: A retrospective clinical study was conducted to analyze the THI-S cutoff score used for referral purpose and the level of predictability between the THI and the THIS. 100 patients participated. The subject samples were drawn from outpatients who reported tinnitus as their primary complaints at the time of the initial audiology and otolaryngology evaluations. The 10-item THI-S, selected by using Cronbach's alpha coefficient, showed a high correlation with the scores of the THI. Based on their clinical experiences, the four otologists developed their own screening versions of THI, which were designated as THI-A, B, C and D. The Pearson product-moment correlation was used to assess the comparability of the scores between the THI and the THI-S, A, B, C and D. RESULTS: The results showed that there is a higher correlation between the THIS and the THI-S. A high comparability was shown in the comparison between the THI and the THI-S. CONCLUSION: Further studies will be needed if the THI-S can be applied for clinical use.

A Case of Glomus Tumor Presented with a Polypoid Mass in the External Auditory Canal / 대한이비인후과학회지

Glomus tumors, also called paragangliomas, originate from nonchromaffin cells. They are slow-growing benign lesions and represent the most common primary neoplasm of the middle ear. It is worth mentioning that the most common symptoms are pulsating tinnitus and hearing loss. Imaging studies (CT and MRI) are necessary for diagnosis. Although most of cases are limited to the middle ear, this article reports a glomus tumor presented with a polypoid mass in the external auditory canal.