Tack-Kyun Kwon

Development of endoscopic arytenoid adduction using cricoid implant

Objectives: We sought to develop a less-invasive alternative to conventional arytenoid adduction using a cricoid implant. Methods: We performed a preliminary study with excised human and canine larynges. A nail-shaped stainless steel rod and an insertion device were designed for an in vivo animal trial. After unilateral recurrent laryngeal denervation surgery in 5 adult mongrel dogs, the implants were inserted endoscopically through a small mucosal incision over the cricoarytenoid joint. Acoustic and aerodynamic data were obtained from each animal before serial euthanasia followed by examination of the excised larynges. Results: The canine cricoid cartilage demonstrated adequate marrow space for implantation. We found that the arytenoid cartilage was successfully medialized and tightly fixed over a sufficient period of time just by inserting an implant in the cricoid cartilage. The animal study showed that the implantation procedure was relatively easy and relatively safe. Acoustic and aerodynamic studies confirmed the functional improvement of the voice. Histopathologic study revealed a favorable tissue response to the implant. Conclusions: Endoscopic arytenoid adduction using a cricoid implant is feasible and could be a noninvasive surgical option for the treatment of unilateral vocal fold paralysis.

Induction chemotherapy in head and neck squamous cell carcinoma of the paranasal sinus and nasal cavity: a role in organ preservation.

Background/Aims: The role of induction chemotherapy (IC) for eyeball preservation has not been established in head and neck squamous cell carcinoma (HNSCC) of the paranasal sinus and nasal cavity (PNSNC). Periorbital involvement frequently leads to eyeball exenteration with a margin of safety. We evaluated the treatment outcomes, including survival and eyeball preservation, of patients who received IC for HNSCC of the PNSNC. Methods: We reviewed 21 patients diagnosed with HNSCC of the PNSNC who were treated with IC. We analyzed response, eyeball preservation rate, and overall survival. Results: Tumors were located in the paranasal sinus (n = 14) or nasal cavity (n = 7). Most patients had stage T4a (n = 10) or T4b (n = 7) disease. More than half of the patients received a chemotherapy regimen of docetaxel, fluorouracil, and cisplatin (n = 11). Thirteen patients (61.9%) achieved a partial response after IC and 15 patients (71.4%) achieved T down-staging. Among 17 patients with stage T4 disease, which confers a high risk of orbital exenteration, 14 (82.4%) achieved preservation of the involved eye. The 3-year overall survival (OS) rate of patients who achieved a partial response to IC was 84.6%. The 3-year OS rate of patients with stable disease or disease progression after IC was 25.0% (p = 0.038). Conclusions: IC could be considered for down-staging patients with advanced T-stage disease. It could also be a reasonable option for eyeball preservation in locally advanced HNSCC of the PNSNC.

Prediction of Extrathyroidal Extension Using Ultrasonography and Computed Tomography

Objectives. The aim of the present study was to evaluate the value of high-resolution ultrasound (US) and computed tomography (CT) scan for preoperative prediction of the extrathyroidal extension (ETE). Methods. We analyzed the medical records of 377 patients with papillary thyroid carcinoma (PTC) with preoperative US and CT scan to calculate the sensitivity, specificity, and positive and negative predictive values of characteristics imaging features (such as contact and disruption of thyroid capsule) for the presence of ETE in postoperative pathologic examination. We also evaluated the diagnostic power for several combinations of US and CT findings. Results. ETE was present in 174 (46.2%) based on pathologic reports. The frequency of ETE was greater in the patients with greater degrees of tumor contact and disruption of capsule, as revealed by both US and CT scans (positive predictive value of 72.2% and 81.8%, resp.). Considering positive predictive values and AUC of US and CT categories, separately or combined, a combination of US and CT findings was most accurate for predicting ETE (83.0%, 0.744). Conclusions. This study suggests that ETE can be predicted most accurately by a combination of categories based on the findings of US and CT scans.

Measurement of Cross-Sectional Dimensions of the Cricoid Cartilage: A Computed Tomographic Study:

Objectives: We measured the cross-sectional dimensions of the cricoid cartilage and degrees of ossification of the marrow space for designing a cricoid implant. Methods: We reviewed 100 age- and sex-matched neck computed tomography scans that were performed at Seoul National University Hospital from 2001 to 2005. Under a standardized computed tomography window setting, the height of the cricoid cartilage marrow and the thickness of the marrow space and the ossified inner and outer cortices were measured by one observer. Results: The mean height of the cricoid cartilage marrow was 13.6 mm (range, 5.5 to 20.5 mm) in women and 17.5 mm (range, 13.0 to 24.5 mm) in men. The mean thickness of the cricoid cartilage marrow was 3.17 mm (range, 1.22 to 4.75 mm) in women and 5.13 mm (range, 3.42 to 7.60 mm) in men. We also observed that women in general have a higher density of the cricoid marrow than men; 4 women and 1 man had a markedly denser marrow space. There were individual variations in size and density of the cricoid marrow. Conclusions: Human adult cricoid cartilages have sufficient marrow space for cricoid implantation. Preoperative evaluation of the size and density of the cricoid marrow is recommended for individual application of the cricoid implant.

Analysis of Feature Extraction Methods for Distinguishing the Speech of Cleft Palate Patients

This paper presents an analysis of feature extraction methods used for distinguishing the speech of patients with cleft palates and people with normal palates. This research is a basic study on the development of a software system for automatic recognition and restoration of speech disorders, in pursuit of improving the welfare of speech disabled persons. Monosyllable voice data for experiments were collected for three groups: normal speech, cleft palate speech, and simulated clef palate speech. The data consists of 14 basic Korean consonants, 5 complex consonants, and 7 vowels. Feature extractions are performed using three well-known methods: LPC, MFCC, and PLP. The pattern recognition process is executed using the acoustic model GMM. From our experiments, we concluded that the MFCC method is generally the most effective way to identify speech distortions. These results may contribute to the automatic detection and correction of the distorted speech of cleft palate patients, along with the development of an identification tool for levels of speech distortion.

Customized tracheostomy cannula as a therapeutic adjunct in tracheal stenosis.

Tracheotomy is often successfully used to manage tracheal stenosis, as a temporizing measure prior to definitive treatment or a long-term remedy. In some patients, where a sizeable portion trachea is stenotic, the fixed arm of an ordinary tracheotomy tube may not be of sufficient length to satisfactorily maintain the distal tracheal lumen, and commercially available adjustable tubes may not be at hand in certain clinical settings. Herein, we describe a simple method of constructing a temporary tracheotomy tube with an adjustable distal arm, allowing custom fit at the patient bedside.