Lesions of the Alar Ligaments. In Vivo and in Vitro Studies with Magnetic Resonance Imaging

Study Design: This study analyzed anatomic characteristics of the alar ligaments and the possibility of imaging them with magnetic resonance imaging. Also determined was whether artificial ruptures of the alar ligament can be recognized experimentally.

Objective: To determine the ability of magnetic resonance imaging to visualize normal, torn, resected alar ligaments.

Summary Of Background Data: There are no studies about computed tomography or magnetic resonance imaging findings of alar ligaments and after anatomic sections. Direct visualization of the complete ligament is not possible for computed tomography. No precise diagnostic method for showing a ruptured alar ligaments has been described. Magnetic resonance imaging seems to be the method of choice for distinguishing between normal and pathologic soft tissue.

Methods: Fifteen specimens from accident victims underwent anatomic dissection. In addition, ligaments from three groups were examined: 1) eight volunteers, 2) seven patients, and 3) 17 fresh cadaveric specimen before anatomic exploratory dissection. In seven of these specimens, one ligament was cut to simulate an artificial disruption and magnetic resonance imaging was repeated.

Results: Lesions of the alar ligaments were found in four of 15 prepared specimens. Using magnetic resonance imaging, the alar ligaments could be identified in all volunteers, patients, and specimen except one. No ruptures were found in the 17 specimens. Of the seven resected specimens, all cuts could be demonstrated by magnetic resonance imaging.

Conclusion: Magnetic resonance imaging is useful for showing lesions of the alar ligaments because of a high soft tissue contrast, plane independence imaging, possibility of functional scans, and secondary reconstruction from three-dimensional data sets.