Fumimasa Toyomura

Analysis of High-Pitched Phonation Using Three-Dimensional Computed Tomography

OBJECTIVES/HYPOTHESIS Our aim was to use three-dimensional computed tomography (3DCT) to examine arytenoid cartilage movement during a high-pitched tone task. STUDY DESIGN This was a prospective study. METHODS This study included 14 patients with male-to-female gender identity disorder who had undergone 3DCT imaging for surgical simulation between January 2007 and May 2008. First, to prove that the phonation condition was indeed one of the high-pitched phonation, we confirmed the rotational movement of the thyroid cartilage, horizontal gliding movement of the inferior horn, and vocal fold elongation on a high-pitched tone task. Next, we detected the arytenoid cartilage positions of the joint during a comparison of comfortable and high-pitched phonations. We measured the movement direction and movement distance of the arytenoid cartilage. RESULTS In all cases, the cricothyroid space became narrower (rotation movement), and we observed anterior gliding movement of the inferior horn. In all cases, elongation of the vocal folds by the high-pitched phonation was confirmed and the arytenoid cartilages were displaced both anteriorly and caudally from the position during comfortable phonation by the high-pitched tone task. CONCLUSIONS The arytenoid cartilages did not move posteriorly to elongate the vocal folds during high-pitched phonation. The arytenoid cartilages were pulled anteriorly and moved caudally because of tension associated with vocal fold elongation because of the task of high-pitched phonation. These results suggest that there are no movements at the cricoarytenoid joint that directly control the length of the vocal folds in accordance with pitch.

Analysis of pitch range after arytenoid adduction by fenestration approach combined with type I thyroplasty for unilateral vocal fold paralysis.

OBJECTIVE The purpose of this study was to determine the postoperative pitch range acquired in cases of unilateral vocal fold paralysis, as well as factors affecting outcomes. SUBJECTS AND METHODS We analyzed 39 cases of unilateral vocal fold paralysis for which surgery was performed between January 2006 and January 2009 and for which pitch ranges and the items listed below were measured preoperatively and 1 year postoperatively. Arytenoid adduction (AA) and type I thyroplasty were performed simultaneously in all cases regardless of preoperative severity. AA was performed by the fenestration approach as previously reported. In this procedure, the cricoarytenoid and cricothyroid joints are not released. Correlations between pitch range acquired postoperatively and the following items were examined: (1) pre- and postoperative maximum phonation time (MPT), (2) pre- and postoperative mean airflow rate (MFR), and (3) preoperative pitch range. Furthermore, patients were surveyed regarding their ability to sing after surgery, and the pitch range cutoff value dividing ability and inability to sing was calculated. RESULTS Pitch range increased significantly from 3±4.47 halftones (mean ± standard deviation) preoperatively to 17.5±5.80 halftones postoperatively. Preoperative MPT, MFR, and pitch range did not correlate with postoperative pitch range. Postoperatively, only MPT correlated with the width of postoperative pitch range. Twenty-three of 39 subjects (59%) responded that they were able to sing, and the pitch range cutoff value dividing the two groups was 22 halftones. CONCLUSION AA and type I thyroplasty significantly expanded postoperative pitch range. There was no correlation between preoperative severity and width of pitch range acquired postoperatively.

Features of Vocal Fold Adductor Paralysis and the Management of Posterior Muscle in Thyroplasty.

OBJECTIVE To present the pathologic characteristics of unilateral recurrent nerve adductor branch paralysis (AdBP), and to investigate the management of posterior cricoarytenoid (PCA) muscle on the basis of our experience of surgical treatment for AdBP. STUDY DESIGN This is a retrospective review of clinical records METHODS Four cases of AdBP, in which surgical treatment was performed, are presented. AdBP shows disorders of vocal fold adduction because of paralysis of the thyroarytenoid and lateral cricoarytenoid muscles. The PCA muscle, dominated by the recurrent nerve PCA muscle branch, does not show paralysis. Thus, this type of partial recurrent nerve paresis retains the abductive function and is difficult to distinguish from arytenoid cartilage dislocation because of their similar endoscopic findings. The features include acute onset, and all cases were idiopathic etiology. Thyroarytenoid muscle paralysis was determined by electromyography and stroboscopic findings. The adduction and abduction of paralytic arytenoids were evaluated from 3 dimensional computed tomography (3DCT). RESULTS In all cases, surgical treatments were arytenoid adduction combined with thyroplasty. When we adducted the arytenoid cartilage during inspiration, strong resistance was observed. In the two cases where we could cut the PCA muscle sufficiently, the maximum phonation time was improved to ≥30 seconds after surgery, from 2 to 3 seconds preoperatively, providing good postoperative voices. In contrast, in the two cases of insufficient resection, the surgical outcomes were poorer. CONCLUSIONS Because the preoperative voice in AdBP patients is typically very coarse, surgical treatment is needed, as well as ordinary recurrent nerve paralysis. In our experience, adequate PCA muscle resection might be helpful in surgical treatment of AdBP.