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Objectives: The purpose of this study is to investigate the characteristics of vocal fold vibration during sustained vowel /a/ phonation and various semi-occluded vocal tract exercise (SOVTEs) using a vibration simulator and digital kymography (DKG).Methods: A total of 12 normal young speakers (6 males, 6 females) aged 20-30 years participated in the study. They phonated a sustained /a/ vowel and performed SOVTE. The vocal fold vibration characteristics were measured according to the number of vibration sources (single vs. double), and vocal tract occlusion degree using a vibration simulator and DKG. Glottal gap quotient (GQ, %), speed quotient (SQ, %) and amplitude (pixel) were estimated quantitatively from the DKG image.Results: The results showed that significantly higher GQ (p = .000) and SQ (p = .000) were observed in the humming and bilabial fricative /β/ compared to open vowels. The amplitude was significantly higher in the open vowel /a/ than in humming (p = .018) and bilabial fricative /β/ (p = .003). Also, when comparing the vocal fold vibration parameters according to vibration type (single source: straw phonation vs. double source: straw phonation with water), the double source presented a significantly higher GQ (p = .000) as well as SQ (p = .008) in comparison with a single source.Conclusion: SOVTE showed a glottal gap that is different from the opened vowel /a/. It also had a longer opening of the vocal fold and a smaller amplitude than the vowel. This suggests that SOVTE may be helpful for facilitating vocal fold vibration and good voice quality in clinical practice. The current study can be meaningful in providing theoretical and clinical evidence for SOVTE.

The purpose of study is to improve the classification accuracy by comparing the results obtained by applying decision tree ensemble learning, which is one of the methods to increase the classification accuracy for a relatively small dataset, with the results obtained by the convolutional neural network (CNN) algorithm for the diagnosis of glottal cancer.Pusan National University Hospital (PNUH) dataset were used to establish classifiers and Pusan National University Yangsan Hospital (PNUYH) dataset were used to verify the classifier's performance in the generated model. For the diagnosis of glottic cancer, deep learning-based CNN models were established and classified using laryngeal image and voice data. Classification accuracy was obtained by performing decision tree ensemble learning using probability through CNN classification algorithm. In this process, the classification and regression tree (CART) method was used. Then, we compared the classification accuracy of decision tree ensemble learning with CNN individual classifiers by fusing the laryngeal image with the voice decision tree classifier.We obtained classification accuracy of 81.03 % and 99.18 % in the established laryngeal image and voice classification models using PNUH training dataset, respectively. However, the classification accuracy of CNN classifiers decreased to 73.88 % in voice and 68.92 % in laryngeal image when using an external dataset of PNUYH. To solve this problem, decision tree ensemble learning of laryngeal image and voice was used, and the classification accuracy was improved by integrating data of laryngeal image and voice of the same person. The classification accuracy was 87.88 % and 89.06 % for the individualized laryngeal image and voice decision tree model respectively, and the fusion of the laryngeal image and voice decision tree results represented a classification accuracy of 95.31 %.The results of our study suggest that decision tree ensemble learning aimed at training multiple classifiers is useful to obtain an increased classification accuracy despite a small dataset. Although a large data amount is essential for AI analysis, when an integrated approach is taken by combining various input data high diagnostic classification accuracy can be expected.

Vocal dysfunction is one of the major factors that affect the health-related quality of life of patients after thyroidectomy. Conventionally, voice changes after thyroidectomy have been evaluated by videostroboscopy and acoustic analysis. Recently, two-dimensional scanning digital kymography (2D DKG) and high-speed videolaryngoscopy (HSV) have been developed and have shown usefulness in accurately evaluating vocal fold vibration. This study aimed to evaluate changes of vocal fold vibration and voice after thyroidectomy using 2D DKG and HSV.We evaluated the voice and vocal fold movement of 24 female patients who underwent thyroidectomy in a single tertiary hospital from December 2018 to October 2019. We obtained serial 2D DKG and HSV data one day before thyroidectomy, and 1 week and 1 month after surgery. We analyzed the peak glottal area of HSV, amplitude symmetry index, phase symmetry index, and open quotient using the 2D DKG data. The parameters were calculated at three levels of the vocal fold (line 1=anterior, line 2=middle, line 3=posterior). In the same period, we performed a voice analysis evaluating voice frequency, jitter, shimmer, and noise to harmonic ratio. We also assessed maximum phonation time and subjective voice changes with voice handicap index-10 questionnaires.Highest frequency (F-high), frequency range (F-range), and fundamental frequency (F0) decreased at 1 week and 1 month after thyroidectomy compared with preoperative values (P = 0.003, 0.004,0.001 and P = 0.002, 0.015, 0.001 at 1 week and 1 month, respectively). The open quotient of 2D DKG in lines 1 and 2 increased at 1 week after thyroidectomy (P = 0.011, 0.006) and recovered to preoperative levels at 1 month postoperatively (P = 0.189, 0.153). Other quantitative measures by 2D DKG and HSV did not show significant changes between the preoperative and postoperative periods. In a correlation analysis between vocal parameters from the acoustic analysis and the values obtained from 2D DKG and HSV, significant negative correlations were observed between peak glottal area and three factors (F-high, F-range, and F0) at 1 month after surgery (r = -0.589, -0.529, -0.708; P = 0.002, 0.008,0.001, respectively). There were positive correlations between phase symmetry indexes in lines 1 and 2 and shimmer at 1 week after thyroidectomy (r = 0.489, 0.425; P = 0.015, 0.038, respectively). Phase symmetry index in line 3 showed a significant negative correlation with maximum phonation time at both 1 week and 1 month after surgery (r = -0.497, -0.439; P = 0.013, 0.032, respectively). However, there was no correlation between total score on the voice handicap index-10 questionnaires and quantitative measurements of vocal fold vibration.2D DKG and HSV may provide important information on vocal fold vibratory patterns after thyroidectomy, and measurements made with them were correlated with maximal phonation time and acoustic parameters such as F-high, F-range, F0, shimmer.

Summary Objective Although laryngeal videostroboscopy is widely utilized in the analysis of vocal fold vibrations, it is often difficult to identify patterns of vocal fold vibrations in patients with aperiodic voice signals due to failure of synchronization during laryngeal videostroboscopy examination. Therefore, the present study aimed to compare the usefulness of simultaneous two-dimensional digital kymography (2D DKG) and traditional DKG for the detection of changes in the pattern of vocal fold vibrations in patients with vocal fold scarring (VFS). Methods Seven patients with VFS and one normal subject underwent high-speed videoendoscopy (HSV). DKG and 2D DKG evaluations of vocal fold vibrations were performed simultaneously, following which both qualitative and quantitative analyses were performed. Results Simultaneous DKG and 2D DKG enabled observation of vibratory patterns as well as amplitude and phase symmetry. DKG revealed and provided temporal information regarding the pattern of vocal fold vibrations at sites of VFS. In contrast, 2D DKG provided real-time information regarding the pattern of vibrations for the whole vocal fold region and regions of increased stiffness, as well as spatial information regarding changes in this pattern. Conclusion Our findings indicate that 2D DKG enables the assessment of overall vocal fold vibrations, regardless of periodicity, and that simultaneous DKG and 2D DKG can be used to confirm abnormal patterns of vocal fold vibrations in patients with impaired flexibility and elasticity of the vocal folds.

Tissue engineering is a cutting-edge discipline in biomedicine. Cell culture techniques can be applied for regeneration of functional tissues and organs to replace diseased or damaged organs. Scaffolds are needed to facilitate the generation of three-dimensional organs or tissues using differentiated stem cells in vivo. In this report, we describe a novel method for developing vascularized scaffolds using decellularized rat kidneys. Eight-week-old Sprague-Dawley rats were used in this study, and heparin was injected into the heart to facilitate flow into the renal vessels, allowing heparin to perfuse into the renal vessels. The abdominal cavity was opened, and the left kidney was collected. The collected kidneys were perfused for 9 h using detergents, such as Triton X-100 and sodium dodecyl sulfate, to decellularize the tissue. Decellularized kidney scaffolds were then gently washed with 1% penicillin/streptomycin and heparin to remove cellular debris and chemical residues. Transplantation of stem cells with the decellularized vascular scaffolds is expected to facilitate the generation of new organs. Thus, the vascularized scaffolds may provide a foundation for tissue engineering of organ grafts in the future.

Summary Objective The purpose of this study was to evaluate the clinical feasibility and diagnostic accuracy of two-dimensional scanning digital kymography (2D DKG) in patients with vocal cord atrophy before and after treatment. Materials and Methods We analyzed the characteristics of vocal fold vibration in five patients with unilateral vocal fold paralysis and five patients with presbyphonia. In patients with vocal cord paralysis, the status before and after intracordal injection was compared. Furthermore, in patients with presbyphonia, we compared the status before and after voice therapy (Seong-Tae Kim's laryngeal calibration technique). Quantitative parameters such as amplitude and phase symmetry indices, jitter, shimmer, noise-to-harmonic ratio, and maximum phonation time and qualitative parameters such as Voice Handicap Index, glottal gap, amplitude, and phase difference were used to evaluate the pre- and post-treatment status. Results In cases of vocal cord paralysis, vibratory changes of the vocal folds before and after intracordal injection could be identified immediately using 2D DKG. In overcorrection cases, all of the measured parameters were poor except for improvement of the glottal gap. In addition, 2D DKG showed appropriately the changes in vocal cord vibration before and after voice therapy in patients with presbyphonia. Conclusion Two-dimensional DKG may be a useful diagnostic tool in evaluation of the vibratory characteristics of entire vocal cords. In addition, it may also play a role in providing a decision for treatment modalities.

Objective: This study aimed to evaluate the feasibility of the gasless transoral endoscopic thyroidectomy vestibular approach (TOETVA) using the Thyroidoscope, developed to maintain the surgical working space without CO2 insufflation. Materials and Methods: To prevent a potentially fatal CO2-related complication, we developed a retractable device, named the Thyroidoscope, which could maintain the surgical working space without CO2 insufflation. We conducted a preclinical cadaver study to evaluate its use in gasless TOETVA. Results: The Thyroidoscope provided a secure surgical field and stable image on the screen. We could successfully identify the recurrent laryngeal nerve, parathyroid gland, and other critical structures without inadvertent injury due to insertion of the Thyroidoscope. Conclusions: The Thyroidoscope provides sufficient working space to perform transoral thyroid surgery without the need for CO2 insufflation. Gasless TOETVA with the Thyroidoscope seems to be feasible and safe.

Summary Background A digital kymogram shows real images of vocal fold vibration. However, DKG is difficult to use in clinical practice because the recorded image cannot be seen instantaneously after examination, as considerable encoding time is required to visualize a digital kymogram. In addition, frame-by frame analysis should be implemented to evaluate high-speed videoendoscopy data, but is time- and labor-intensive. Purpose The purpose of the study was to validate the clinical practicability of a real-time multislice digital kymographic system developed by the authors. We analyzed the promptness and accuracy of the examination before and after intracordal injections in patients with unilateral vocal fold paralysis. Methods To assess the clinical applicability of this system, six patients with unilateral vocal fold paralysis were selected. Real-time DKG was performed before and immediately after intracordal injection. We observed changes in the digital kymogram after the intracordal injection. Results Using this system, 10 scanning lines and up to five vertical pixel row could be obtained in real time, and the maximum acquisition time for the DKG image was 10 seconds. A digital kymogram of the patients could be instantaneously acquired, and whether the intracordal injection was appropriate or not. Conclusion This article is the first validation study after the development of the real-time multislice digital kymographic system. Our system may be a promising tool in clinical practice for immediate assessment of the vibratory patterns of the vocal cords. More research is necessary for further clinical validation.

Fillers are products that fill the space in soft tissues of the human body and actively used in the various medical fields. Unfortunately, most of the cost-effective commercially available fillers are synthetic and have limitations in terms of their biocompatibility. Here, we evaluated the possible application of decellularized xenogenic cartilage as a long-lasting material for soft tissue augmentation and compared it with two commercially available fillers Artesense (polymethylmethacrylate microspheres) and Radiesse (calcium hydroxyapatite [CaHa]). To do so, porcine auricular cartilage was harvested, followed by freezing and grinding of the tissue into flakes. Then, we used 1% Triton X-100 to decellularize the flakes. We then, respectively, injected 0.1 cc of each material (decellularized xenogenic cartilage, Radiesse, and Artesense) into the subcutaneous layer at three different sites per subject in 12 Sprague-Dawley rats, and evaluated the inflammatory cell infiltration and foreign body reactions of each. Our data indicate that the infiltration of giant cells in the injection area was significantly lower in the decellularized xenogenic cartilage injection group than that in the Radiesse and Artesense injection groups. Further, we observed some neutrophil infiltration in the xenogenic cartilage and Artesense injection groups at 1 month, but these levels were much lower at 3 months (comparable to the Radiesse injection group). Thus, decellularized xenogenic cartilage may have a distinct advantage in terms of biocompatibility compared with other commercial injectable long-lasting fillers, making it one of the most feasible, natural, and cost effective materials in the market. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2708-2715, 2018.

Objectives/hypothesis Anatomical variations of the recurrent laryngeal nerve (RLN), such as extralaryngeal branching, are a well-known risk factor for RLN injury during thyroid surgery. This study aimed to analyze the surgical anatomy and to investigate the existence of posterior branch motor fibers of extralaryngeal RLNs. Study design Prospective consecutive observational study. Methods This was a prospective cohort study of 366 patients between January 2014 and February 2016. Operative data included the type of operation, incidence of nerve bifurcation, the distances among anatomical landmarks. The motor fibers were evaluated using neurostimulation with laryngeal palpation. Results A total of 667 RLNs at risk were analyzed in this study, and of these 103 (14.5%) nerves were bifurcated or trifurcated before the laryngeal entry point (LEP). More extralaryngeal branched RLNs were observed on the right side than on the left (17.5% vs. 13.3%, P = .294). The mean distance of the LEP point of division was longer on the left side (16.2 ± 6.7 mm) than on the right (14.7 ± 5.9 mm, P = .132). All branched RLNs had a palpable laryngeal twitch when stimulating anterior branches. When stimulating posterior branches, 28.2%(29/103) of branched RLNs showed palpable laryngeal twitch. Overall incidence of posterior motor branch in total RLNs was 4.3% (29/667). Conclusions The motor fibers of the RLN are all located in the anterior branch, whereas some posterior branches have motor function. Identification of all of the branches of the RLN may be mandatory to decrease the risk of postoperative nerve injury. Level of evidence 4. Laryngoscope, 127:2678-2685, 2017.

Objective Currently, various tools have been introduced for the assessment of vocal fold vibration: laryngeal videolaryngoscopy (LV), videokymography (VKG), high speed videoendoscopy (HSV), digital videokymography (DKG), and 2D scanning videokymography (2D VKG). Among these, the authors have recently designed a dual modality examination system using LV and 2D VKG for more detailed information regarding the vibrations of the vocal folds. The clinical availability of this hybrid system offers medical imaging departments a range of potential advantages in the evaluation of vocal fold vibration. The obvious benefit of simultaneous acquisition is the improved integration of information that allows not only optimal anatomic localization, but also physical movement patterns. Other advantages include the lessened inconvenience to patients due to no longer requiring repeated examinations and shortening the examination time, and increased profitability. The purpose of study was to identify the efficacy of real-time dual examination of two different modalities for the evaluation of vocal fold vibration in human subjects and vocal fold vibration simulator. Methods One vocally healthy subject and three patients with vocal fold nodules, a vocal cyst, and vocal fold paralysis took part in this study. The vibratory patterns of the vocal folds were visualized using simultaneous real-time examination of two different modalities. Additionally, qualitative and quantitative analyses of the dual LV and 2D VKG images were performed. Results Real-time dual examination using a two modality system provided high definition images of the vibratory movements of the vocal folds. By assessing the obtained images, we confirmed that the dual modality examination method was useful in the evaluation of pathologic vibratory patterns, even in non-periodic phonation. Conclusion The present system might improve the understanding of the processes of vocal fold vibration and make a contribution to pathologic voice research, as well as clinical practice.

Background This study aimed to investigate the relationships between serum vascular endothelial growth factor (VEGF)-A or VEGF-C levels and lymph node metastasis (LNM) status in patients with papillary thyroid carcinoma (PTC). Methods The study enrolled 150 patients with pathologically proven PTC who underwent surgery: PTC without LNM, PTC with central neck metastasis, and PTC with lateral neck metastasis. Results Preoperative serum VEGF-A levels were 300.12 ± 80.80 pg/mL overall and were not correlated with the presence of LNM. Preoperative serum VEGF-C levels were 132.41 ± 48.48 pg/mL overall and were significantly correlated with the presence of LNM. Serum VEGF-C levels were further increased in patients with lateral neck metastasis and positively correlated with the number of metastatic LNs (rho = 0.252, P = 0.002). Serum VEGF-C, but not VEGF-A, was identified as a significant predictor of lateral neck metastasis. Conclusion Serum VEGF-C might be a clinically relevant biomarker of lateral neck metastasis in patients with PTC.

Objectives To clarify the anatomical distribution of the lingual artery in normal adult subjects through histopathologic evaluations. Methods Eighteen healthy cadaveric tongues were used to produce 8 paraffin-embedded tissue sections each. Length from midline raphe, depth from dorsum of tongue and the whole transverse length tongue were measured. The lateral distance, depth, and proportion of lateral distance of deep lingual artery were determined from tip to base of tongue gradually. Lateral distance is length from median raphe to the center of deep lingual artery lumen. Depth is vertical distance from dorsal surface of tongue to the center of deep lingual artery. Proportion of lateral distance is obtained by dividing lateral distance with transverse length from median raphe to lateral border of tongue. The degree of symmetry between right and left sides and the difference between selected spots were evaluated. Results Right and left sides of the lingual artery were symmetric. The lingual artery was lateralized as it run posterior. The lingual artery runs gradually deeper from the surface as it goes near the base of tongue. Both length and depth of the lingual artery gradually increased between 0%-75% of the mobile tongue, but 75%-100% zone of the lingual artery showed no significant difference. There was no anastomosis between right and left side of the lingual arteries. The lingual artery was located within 50% of the transverse length of tongue from median raphe. Conclusion The present study reveals 3-dimensional information on the anatomical distributions of the lingual artery in normal adult subjects. These findings gives us beneficial information about the handling of the lingual artery during oral and base of tongue-related surgery.

Objectives/Hypothesis Office-based biopsy (OBB) is widely used to diagnose suspicious laryngeal lesions. However, its routine use is still controversial and the algorithm for clinical strategy is not concrete. We tried to evaluate the accuracy of OBB as a diagnostic tool for laryngeal malignancy. Methods Medical data of 581 patients undergoing OBB were reviewed. Diagnostic values of OBB were analyzed for malignancy and malignancy/premalignancy. False negative rates (FNRs) were analyzed according to subsites, lesion sizes, and morphology. Results The collection rate of adequate specimens was 99.1%, and there were no complications during OBB. The false omission rates for malignancy of benign lesion; mild, moderate, and severe dysplasia; and carcinoma in situ (CIS) were 5.1%, 11.9%, 14.3%, 50.0%, and 100.0%, respectively. Sensitivity, specificity, positive predictive value, and negative predictive value for malignancy in OBB were 78.2%, 100.0%, 100.0%, and 87.3%, respectively. Those for malignancy/premalignancy in OBB were 88.2%, 86.7%, 85.7%, and 89.1%, respectively. The high FNRs were reported in glottis lesions (27.0%) and small lesions below 1 cm (27.5%). Morphologically fungating lesions showed low FNR (9.1%) compared to nonfungating ones. Conclusion Office-based biopsy could be used as an initial diagnostic tool for laryngeal malignancy for early detection and avoidance of general anesthesia. However, operative re-biopsy should be considered when severe dysplasia or CIS were reported in OBB, or when the lesions are clinically suspicious for malignancy. Level of Evidence 4. Laryngoscope, 2016

Objectives/Hypothesis Recurrent laryngeal nerve (RLN) injury during thyroidectomy or parathyroidectomy is a challenging issue and causes significant morbidity. We adopted the supramaximal stimulation protocol for neurostimulation with laryngeal palpation (NSLP) and tried to evaluate the predictive values of supramaximal NSLP for immediate postoperative vocal fold (VF) mobility. Study Design Prospective cohort study. Methods Prospectively, 293 patients who underwent thyroid and parathyroid surgery and 542 RLNs at risk were enrolled in this study. During NSLP, the current was escalated to 3 mA until definite laryngeal twitch was observed. Immediate postoperative VF mobility was evaluated using flexible laryngoscopy. Results Diagnostic accuracy of NSLP is calculated according to cutoff values of minimal current intensity (1 mA, 1.5 mA, and 2 mA). At 2mA, sensitivity was 81.82%, specificity 100%, positive predictive value 100%, and negative predictive value 99.62%. Conclusions Supramaximal NSLP might be a simple and reliable method to predict immediate postoperative VF mobility in open thyroid and parathyroid surgeries when intraoperative neuromonitoring is unavailable. Level of Evidence 4. Laryngoscope, 2016

Background/Aims: The purpose of this study was to compare the diagnostic validity of two-dimensional (2D) and three-dimensional (3D) ultrasonography (US) when predicting the extrathyroidal extension of papillary thyroid cancer. Methods: All 2D data were interpreted in real time and 3D data were stored, rendered using tomographic ultrasound imaging (TUI), and then reviewed retrospectively. Results: Extrathyroidal extension was present in 17 papillary thyroid cancers(24.3%) on pathology reports. The presence of contact was significantly associated with extrathyroidal extension on both 2D and 3D US (p = 0.007 and p = 0.003), and the sensitivity and specificity were not significantly different between 2D and 3D US (p = 1.000 and p = 0.754). The coexistence of protrusion and contact was not significantly associated with extrathyroidal extension on either 2D or 3D sonogram. Conclusions: Three-dimensional images rendered with TUI algorithms alone do not seem to be markedly superior to real-time 2D US in predicting the extrathyroidal extension of papillary thyroid cancer.

Conclusion Loco-regional recurrence-free survival was significantly decreased in the papillary thyroid cancer patients with > 6 metastatic lymph nodes and a lymph node ratio > 0.22. Also, the risk of lung metastasis was significantly increased in cases with bilateral neck node metastases. Objective This study focused on the metastatic lymph node status of the lateral neck compartment to understand its prognostic significance for loco-regional recurrence and distant metastasis. Methods Between January 2004 and December 2009, 1040 patients were diagnosed with papillary thyroid cancer and underwent treatment. Results In a multivariate analysis, sex, the number of metastatic lymph nodes, and the lymph node ratio was significantly associated with loco-regional recurrence. The sensitivity/specificity of > 6 metastatic lymph nodes for predicting recurrence was 64.0%/69.7%. The 5-year loco-regional recurrence-free survival of patients with 0-6 metastatic lymph nodes and > 6 metastatic lymph nodes were 93.4% and 79.2%, respectively. The 5-year loco-regional recurrence-free survival of patients with a lymph node ratio ≤ 0.22 and a lymph node ratio > 0.22 were 97.1% and 78.8%, respectively. In the multivariate analysis, only bilateral neck node metastases were significantly associated with lung metastasis.

The purpose of this study was to explore the concurrent validity of the Acoustic Voice Quality Index (AVQI) in a Korean population. We investigated the feasibility of its cutoff values and diagnostic accuracy in discriminating between normal and dysphonic voices.A total of 1,524 native Korean subjects with normal voices (n = 113) and with voice disorders (n = 1,411) were asked to speak and sustain the vowel "a" and to read the Korean text "Walk" aloud. A 2-second mid-speech portion of the sustained vowel sound and two sentences (with 26 syllables) were edited and concatenated, and the AVQI was calculated. Additionally, two auditory-perceptual assessments, namely the Grade, Roughness, Breathiness, Asthenia, Strain scale, and the Consensus Auditory-Perceptual Evaluation of Voice were used by five speech language pathologists to rate the severity of dysphonia.Both auditory-perceptual assessments showed high confidence levels among the five speech language pathologists. The AVQI correlated with grade (G) and overall severity (OS). There were statistically significant differences in AVQI, G, and OS between normal and pathological speech groups. In the receiver operating characteristic curve analysis, AVQI, G, and OS cutoff values were3.33,0.00, and22.00, respectively. The receiver operating characteristic curve analysis indicated that AVQI had excellent diagnostic accuracy for discriminating between normal and dysphonic voices (area under the curve: 0.970-0.977).We demonstrated the concurrent validity of AVQI as a promising tool for assessing overall voice quality and quantifying dysphonia in a Korean-speaking population.

Purpose: The aims of this study were to: (1) determine the visual analogue scale (VAS) and cepstrum peak prominence (CPP) cut-off points on the ratings of numerical scale (NS) related to the severi...

Optical Coherence Tomography (OCT) is a promising non-invasive in vivo imaging technology visualizing the 3-dimensional microanatomy of retina, skin and vocal fold. In the field of laryngology, OCT probes installed in an existing laryngoscope have been widely studied. However, there are still a number of critical issues to be resolved to develop a successful phonomicrosurgical OCT system including high-resolution, long working distance (≥400 mm) and rapid 3D image reconstruction, etc. Here we introduce a long working distance OCT with 35µm lateral and 13µm axial resolutions. To the best of our knowledge, this is the first OCT with up to 450mm of working distance as well as µm-level resolutions to identify subepithelial tissue structure of vocal fold. The main purpose of this study is to investigate the feasibility and efficacy of the system in ex-vivo microstructure imaging of vocal fold, especially the Reinke’s space. We tested the imaging capability of the system with the freshly excised canine eyeball and larynx samples before proceeding the study with fresh human laryngectomized specimens. The acquired OCT images were then compared with the corresponding H&E stained histological sections. This correlation study allowed the identification of the epithelial layer, lamina propria, subepithelial glandular structures and vessels of the canine and human specimens from both the OCT and the microscope images ensuring solid correspondence between two different types of visual tissue assessment. This OCT system is developed to directly confirm the lesions during phonomicrosurgeries enabling the clinicians to reduce the number of intraoperative biopsies.

Summary Objective The purpose of this study was to analyze the acoustic characteristics associated with alternation deformation of the vocal tract due to large epiglottic cyst, and to confirm the relation between the anatomical change and resonant function of the vocal tract. Methods Eight men with epiglottic cyst were enrolled in this study. The jitter, shimmer, noise-to-harmonic ratio, and first two formants were analyzed in vowels /a:/, /e:/, /i:/, /o:/, and /u:/. These values were analyzed before and after laryngeal microsurgery. Results The F1 value of /a:/ was significantly raised after surgery. Significant differences of formant frequencies in other vowels, jitter, shimmer, and noise-to-harmonic ratio were not presented. Conclusion The results of this study could be used to analyze changes in the resonance of vocal tracts due to the epiglottic cysts.

BACKGROUND/AIM We aimed to explore the prognostic value of metabolic heterogeneity of 18F-FDG uptake in chemoradiotherapy-treated pharyngeal cancer patients. PATIENTS AND METHODS This study included 52 consecutive patients with pharyngeal cancer who underwent 18F-FDG PET/CT before definitive chemoradiotherapy. The heterogeneity factor (HF) was defined as the derivative (dV/dT) of a volume-threshold function for primary tumors and metastatic lymph nodes. The relationships between clinical parameters and HFs of primary tumors (pHF) and metastatic lymph nodes (nHF) were analyzed. RESULTS The pHF (range=∓1.367 - -0.027; median=-0.152) was significantly correlated with the maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis. Induction chemotherapy response was not correlated with HF, whereas response to radiotherapy was significantly better in patients with high pHF (low heterogeneity). Consistently, the 2-year locoregional recurrence-free survival was significantly better in patients with high pHF (82.9% for pHF>-0.152 vs. 30.5% for pHF

Objectives/Hypothesis Vocal fold injection is a minimally invasive technique for various vocal fold pathologies. The shortcomings of the cricothyroid (CT) membrane approach are mainly related to invisibility of the injection needle. If localization of the needle tip can be improved during vocal fold injection with the CT approach, the current problems of the technique can be overcome. We have conceptualized real-time light-guided vocal fold injection that enables simultaneous injection under precise localization. In this study, we developed a device for real-time light-guided vocal fold injection and applied it in excised canine larynx. Study Design Animal model. Methods A single optic fiber was inserted in an unmodified 25-gauge needle. A designated connector for the device was attached to the needle, the optic fiber, and the syringe. A laser diode module was used as the light source. An ex vivo canine larynx model was used to validate the device. Results The location of the needle tip was accurately indicated, and the depth from the mucosa could be estimated according to the brightness and size of the red light. The needle was inserted and could be localized in the canine vocal fold by the light of the device. Precise injection at the intended location was easily performed with no manipulation of the device or the needle. Conclusions Real-time light-guided vocal fold injection might be a feasible and promising technique for treatment of vocal fold pathology. It is expected that this technique can improve the precision of vocal fold injection and expand its indication in laryngology. Level of Evidence NA Laryngoscope, 2015

Background The purpose of this study was to present our focus on the lymph node status in the central compartment and evaluate the relevant factors and disease recurrence. Methods Between January 2004 and December 2009, 1040 patients were diagnosed with papillary thyroid carcinoma (PTC) and underwent surgery. Results The number of metastatic lymph nodes was a significant predictor for recurrence conferring a hazard ratio of 1.36 (confidence interval = 1.103–1.680; p = .004). The receiver operating characteristic (ROC) curve was calculated to determine the cutoff number of lymph nodes that predicted recurrence with the highest sensitivity and specificity (area under the ROC curve, 0.794; SE, 0.077; p = .001). The sensitivity/specificity of >3 metastatic lymph nodes for predicting recurrence was 63.6%/77.0%, respectively. Conclusion The number of metastatic lymph nodes in the central compartment was a statistical significant predictive factor associated with disease recurrence. Further study is required to confirm the relationship between the number of lymph nodes and disease recurrence. © 2015 Wiley Periodicals, Inc. Head Neck, 2015

Objectives/Hypothesis Endoscope-assisted transoral removal of a thyroglossal duct cyst (TGDC) has been introduced to clinical practice. However, the technical feasibility, efficacy, and safety of this procedure have not been studied. Herein, we conducted a prospective clinical trial to evaluate endoscope-assisted transoral removal of a TGDC. Study Design Prospective cohort study. Methods Thirty patients were included. We performed endoscope-assisted transoral removal of TGDCs and evaluated the clinical results and complications over more than 2 years. Results Endoscope-assisted transoral resection was successful in all cases. However, transient morbidity was noted in one patient. The mean operation time was 67.33 ± 17.26 minutes. Surgery was not required for recurrence or revision during a follow-up. Conclusions Endoscope-assisted transoral resection of a TGDC is a potentially safe and effective procedure leading to excellent functional and cosmetic outcomes. Additionally, considering the embryological development of TGDCs, the transoral approach can open a new access route to these cysts. Level of Evidence 2b. Laryngoscope, 2015

Background The purpose of this study was to determine if hyperinsulinemia and/or insulin resistance are/is associated with the prevalence of papillary thyroid cancer (PTC) in Korean women. Methods This study included 735 female patients with PTC and 537 female non-PTC control subjects. Multiple logistic regression analysis was performed to evaluate the associations between hyperinsulinemia/insulin resistance and the occurrence of PTC. Results The prevalence of PTC was significantly correlated with increased insulin, glucose levels, and a high homeostasis model of assessment-insulin resistance (HOMA-IR). The multivariate adjusted odds ratios for the prevalence of PTC in the highest quartile groups for insulin, glucose, and HOMA-IR were 2.88, 9.32, and 4.07 (all p < .001), respectively, compared with the lowest quartile groups. Pathological analyses revealed that increased serum glucose, insulin levels, and a higher HOMA-IR were associated with the multifocality of PTC. Conclusion Hyperinsulinemia and/or insulin resistance may be associated with the development of PTC, but not disease severity in Korean women. © 2015 Wiley Periodicals, Inc. Head Neck 38: 66–71, 2016

Changes in the configuration of sinonasal cavity after surgery have been assumed to cause changes in the voice quality. The purpose of this study was to know when the hypernasality will be recovered after sinonsal surgery in patients with nasal septal deviation or chronic rhinosinusitis by checking long-term and serially obtained nasalance scores using nasometer. Sixty-five patients underwent sinonasal surgery were included. We classified the subjects into three groups according to the different surgical interventions employed: septoplasty group, endoscopic sinus surgery (ESS) group, and ESS with septoplasty group. The nasalance scores were obtained using a nasometer preoperatively, 1, 2, 3, 4, 5, and 6 months after surgery. The mean nasalance scores for vowels, nasal consonant, plosive consonant-vowel combinations, nasal consonant-vowel combinations, a hypernasality sentence, and hyponasality sentence increased significantly after sinonasal surgery. Hypernasality was most prominent in all groups for all acoustic parameters 1 month after surgery. Thereafter nasality decreased and returned to its preoperative level in all groups at 5 months in the [m], [ma], [mi], and hypernasality sentence, but at 6 months in the [a], [i], [u], [p(h)a], [p(h)i], and hyponasality sentence. Sinonasal surgery can change the acoustic characteristics of the vocal tract and produce a significant increase in nasality. After nasality showed the highest scores at 1-month post-surgery, it returned to its preoperative level at 5 or 6 months after surgery depending on the subtype of speech stimuli.

Fillers are products that fill the space in soft tissues of the human body and actively used in the various medical fields. Unfortunately, most of the cost-effective commercially available fillers are synthetic and have limitations in terms of their biocompatibility. Here, we evaluated the possible application of decellularized xenogenic cartilage as a long-lasting material for soft tissue augmentation and compared it with two commercially available fillers Artesense (polymethylmethacrylate microspheres) and Radiesse (calcium hydroxyapatite [CaHa]). To do so, porcine auricular cartilage was harvested, followed by freezing and grinding of the tissue into flakes. Then, we used 1% Triton X-100 to decellularize the flakes. We then, respectively, injected 0.1 cc of each material (decellularized xenogenic cartilage, Radiesse, and Artesense) into the subcutaneous layer at three different sites per subject in 12 Sprague-Dawley rats, and evaluated the inflammatory cell infiltration and foreign body reactions of each. Our data indicate that the infiltration of giant cells in the injection area was significantly lower in the decellularized xenogenic cartilage injection group than that in the Radiesse and Artesense injection groups. Further, we observed some neutrophil infiltration in the xenogenic cartilage and Artesense injection groups at 1 month, but these levels were much lower at 3 months (comparable to the Radiesse injection group). Thus, decellularized xenogenic cartilage may have a distinct advantage in terms of biocompatibility compared with other commercial injectable long-lasting fillers, making it one of the most feasible, natural, and cost effective materials in the market. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2708-2715, 2018.

BACKGROUND Fluorine-18 fluorodeoxyglucose positron emission tomography/CT (18 F-FDG PET/CT) has been widely accepted as an effective method for detecting recurrent papillary thyroid cancer (PTC) in patients with increased serum thyroglobulin (Tg) or Tg antibody (TgAb) levels and negative whole-body scintigraphy (WBS) results. The role of WBS as a diagnostic tool in detecting recurrence has relatively decreased recently. However, only a few studies have examined the usefulness of 18 F-FDG PET/CT for evaluating patients with recurrent PTC, regardless of the WBS results. The purpose of this analysis was to evaluate the diagnostic value and prognostic role of 18 F-FDG PET/CT for patients with recurrent PTC, irrespective of their WBS results. METHODS Sixty-six patients with locoregional recurrent PTC who underwent 18 F-FDG PET/CT and neck CT within 6 months before surgical treatment were included in this retrospective analysis. Imaging findings were compared with postoperative histopathologic results. The diagnostic values of 18 F-FDG PET/CT and neck CT were compared according to the serum Tg and TgAb levels and cervical levels. Each patient's status at the last follow-up was also reviewed, and survival probabilities were estimated using the Kaplan-Meier plot. RESULTS The sensitivity, specificity, and diagnostic accuracy of 18 F-FDG PET/CT for the entire patient group were 38.5%, 90.2%, and 58.3%, respectively. The corresponding neck CT values were 55.0%, 85.7%, and 66.7%, respectively. According to the serum Tg and TgAb levels, except for the specificity, most diagnostic values of 18 F-FDG PET/CT were worse than those of the neck CTs, with or without statistical significance. For the high maximum standardized uptake value (SUVmax) group (SUVmax >10) and the low SUVmax group, the median locoregional disease-free survival times were 33.3 months and 81.8 months, respectively (P < .001). CONCLUSION The diagnostic value of 18 F-FDG PET/CT for localizing recurrent lesions was worse than that of the neck CT, irrespective of the WBS results. However, patients with a higher SUVmax showed a significantly worse prognosis than did those with a lower SUVmax. Therefore, we suggest that, in patients with recurrent PTC, 18 F-FDG PET/CT should be considered for prognostication rather than diagnosis.

Background and Objective: Noninvasive middle and inner ear imaging using optical coherence tomography (OCT) presents some unique challenges for real-time, clinical use in animals and humans. The goal of this study was to investigate whether OCT provides information about the middle and inner ear microstructures by examining extratympanic structures. Materials and Methods: Five mice and rats were included in the experiment, and the swept-source OCT system was tested to identify the middle and inner ear microstructures and to measure the length or thickness of various structures. Results: It was possible to see middle ear structures through the tympanic membrane with the OCT instrument located extratympanically in both rats and mice. We could also obtain the inner ear images through the otic capsule in the mice, but the bulla needed to be removed to visualize the inner ear structures in the rats. The whole apical, middle and basals of the cochlea and the thickness of the otic capsule covering the cochlea could be visualized simultaneously. Conclusions: OCT is a promising technology to assess middle ear and inner ear microanatomy noninvasively in both mice and rats. OCT imaging could provide additional diagnostic information about the diseases of the middle and inner ear.