[Utility of spiral computed tomography in the study of dislocation of cricoarytenoid joint]

To demonstrate the cricoarytenoid relationship presented with spiral computed tomography and to show that the reconstraction of arytenoid dislocation can be presented by using multiplanar reconstruction algorithms.

Fifteen patients with arytenoid dislocation documented by fiberoptic laryngoscopy and strobovideolaryngoscopy and 10 normal person were displayed with spiral CT. A making design of our own has been used to diagnose arytenoid dislocation on axial CT image.

Dislocation of cricoarytenoid joint were consistently demonstrated on several of the overlapping thin axial reconstructions in each of the 15 patients, in whom asymmetry of the bilateral cricoarytenoid joints was noted on axial images. Especially, by means of ordinary protractor, it has been found on the glottic-fissure level that the basal angle of abnormal side in 8 patients is larger than the one of normal side, and smaller in 7 patients, the value-difference of two basal angles ranges from 5 to 45 in 15 patients, 13 of whom ranges from 10 to 30. Whereas right basal angle is equal to left one in 8 except 2 whose value-difference of two basal angles is very small, respectively 2 and 3, in 10 normal person. High-quality sagittal and coronal reconstructive images often were helpful in confirming or clarifying the complex arytenoid orientations.

The findings that two-side basal angle is not equal in triangle of glottic fissure can be used as a parameter to arytenoid dislocation. Spiral CT is a useful adjunct in diagnosing and treating dislocation of cricoarytenoid joint.