Young Hak Park

Usefulness of laryngeal phonation CT in the diagnosis of vocal cord paralysis.

OBJECTIVE The purpose of this study was to determine the effectiveness of laryngeal phonation CT for the diagnosis of vocal cord paralysis by examining the physiologic and functional changes in the larynx during vowel phonation in patients with vocal cord paralysis. SUBJECTS AND METHODS For the control study, three healthy volunteers underwent laryngeal phonation CT while vocalizing the vowels /hee/, /ih/, and /ah/, and reconstructed coronal images of the larynx were obtained. After the control study, 28 patients with unilateral vocal cord paralysis underwent laryngeal phonation CT during /hee/ phonation, which was chosen as a most appropriate vowel for this purpose. Changes in the paralyzed and normal vocal cords were evaluated quantitatively and qualitatively on coronal reconstruction images. RESULTS On the coronal reconstructed images from the healthy volunteers, the normal cords had a shoulder formation appearance, and the cords lay within 1 mm lateral to the midline during phonation. For patients with vocal cord paralysis during /hee/ phonation, the average angle formed by the long axis of the vocal cord and the midline was 71.67 degrees on the affected side and 92.21 degrees on the normal side (p = 0.001). The vocal cord edges lay 1.5 mm lateral to the midline on the affected side and 0.44 mm lateral to the midline on the normal side (p = 0.003). In the qualitative study, the two observers found the coronal reconstructions of the laryngeal phonation CT scans yielded a higher detection rate than did conventional axial CT. CONCLUSION Laryngeal phonation CT proved more useful for evaluating vocal cord paralysis than did conventional CT and can be used as a primary diagnostic tool when vocal cord paralysis is suspected.

Transoral endoscopic thyroidectomy via the tri-vestibular routes: results of a preclinical cadaver feasibility study

The concept of natural orifice transluminal endoscopic surgery (NOTES) is an emerging experimental alternative to conventional surgery that eliminates skin incisions using an endoscope passed through a natural orifice (e.g., mouth, urethra, or anus). This study was designed to evaluate the feasibility and safety of thyroid resection via an entirely transoral tri-vestibular route using endoscopy, and to introduce NOTES to the head and neck area of medicine. We performed ten complete endoscopic thyroid lobectomies with central lymph node dissection via a tri-vestibular approach in fresh-frozen cadavers. A 5-mm endoscope with a deflectable tip was used to visualize the surgical field. Three cannulas were inserted through the midline and bilateral incision sites in the vestibule to position the instruments and endoscope. We refined and described the surgical technique in each step using video clips. We identified and preserved neighboring critical structures during surgery. We also confirmed that there were no obvious remnant thyroid tissues and no injury to the neighboring structures after exploration. The transoral tri-vestibular approach seems to provide a good view and surgical field for endoscopic thyroidectomy. However, the transoral approach for thyroidectomy remains experimental, and the detailed surgical technique should be refined via further clinical studies.

Analysis of Dysphagia Patterns Using a Modified Barium Swallowing Test Following Treatment of Head and Neck Cancer.

Purpose The purposes of this study were to evaluate specific dysphagia patterns and to identify the factors affecting dysphagia, especially aspiration, following treatment of head and neck cancer. Materials and Methods A retrospective analysis of 57 patients was performed. Dysphagia was evaluated using a modified barium swallow (MBS) test. The MBS results were rated on the 8-point penetration-aspiration scale (PAS) and swallowing performance status (SPS) score. Results Reduced base of the tongue (BOT) retraction (64.9%), reduced laryngeal elevation (57.9%), and cricopharyngeus (CP) dysfunction (47.4%) were found. Reduced BOT retraction was correlated with clinical stage (p=0.011) and treatment modality (p=0.001). Aspiration in 42.1% and penetration in 33.3% of patients were observed. Twenty-four patients had PAS values over 6, implying aspiration. Forty-one patients had a SPS score of more than 3, 25 patients had a score greater than 5, and 13 patients had a SPS score of more than 7. Aspiration was found more often in patients with penetration (p=0.002) and in older patients (p=0.026). In older patients, abnormal swallowing caused aspiration even in those with a SPS score of more than 3, irrespective of stage or treatment, contrary to younger patients. Tube feeders (n=20) exhibited older age (65.0%), dysphagia/aspiration related structures (DARS) primaries (75.0%), higher stage disease (66.7%), and a history of radiotherapy (68.8%). Conclusion Reduced BOT retraction was the most common dysphagia pattern and was correlated with clinical stage and treatment regimens including radiotherapy. Aspiration was more frequent in patients who had penetration and in older patients. In contrast to younger patients, older patients showed greater risk of aspiration even with a single abnormal swallowing irrespective of stage or treatment.

Multivariate Analysis of Risk Factors in the Development of a Lower-Pitched Voice After Thyroidectomy

Objectives: Thyroid surgeons frequently encounter outpatients with mobile vocal cords complaining of lower-pitched voices following thyroidectomy. This study investigated the clinical and pathological parameters affecting voice pitch following thyroid surgery. Methods: We analyzed the data of 393 patients with mobile vocal cords and who also underwent thyroid surgery. Speaking fundamental frequency (SFF) and fundamental frequency (F0) were compared before and after surgery. Results: Approximately 26.7% of patients had significantly lowered SFFs (ΔSFF ≥ 12 Hz), and 30.2% exhibited significantly lower sustained vowel F0s (ΔF0 ≥ 12 Hz) following thyroid surgery. On multivariate analysis, only gender: female remained a significant predictor of a clinically significant change in SFF following thyroid surgery (P < .001). Gender: female and extent of surgery: total remained significant predictors of a clinically significant change in F0 after surgery (P = .006 and P = .007, respectively). Conclusions: Appreciable proportions of patients experience lower-pitched voice and related vocal symptoms early after thyroid surgery. Such problems develop more frequently in females who underwent total thyroidectomy.

Imaging features of schwannomas in the oral cavity: report of two cases

Schwannomas arising from the oral cavity are rare, and reports of their imaging features are scarce in the literature. We report two cases of schwannomas involving the oral cavity and describe their computed tomography, magnetic resonance imaging, and ultrasonography findings.