Open AccessThree‐Dimensional Conformation of the Injected Bolus in Vocal Fold Injections in a Cadaver Model
Author(s) -
Mau Ted,
Brewer Jacquelyn M.,
Gatzert Samuel T.,
Courey Mark S.
Publication year - 2011
Publication title -
otolaryngology–head and neck surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.232
H-Index - 121
eISSN - 1097-6817
pISSN - 0194-5998
DOI - 10.1177/0194599810395107
Subject(s) - cadaveric spasm , larynx , vocal folds , bolus (digestion) , cadaver , medicine , anatomy , glottis , fold (higher order function) , phonation , intravenous bolus , anesthesia , audiology , mechanical engineering , engineering
Objective To determine the 3‐dimensional (3D) conformation of the injected bolus in the larynx in vocal fold injections, to understand how the bolus interacts spatially with elements of the laryngeal framework, and to relate the above to clinical observations in performing vocal fold injections. Study Design Excised cadaveric larynx study. Setting Laboratory. Subjects and Methods Vocal folds of 12 human excised cadaveric larynges were injected with calcium hydroxylapatite. High‐resolution computed tomography scans were obtained of the injected larynges. Densities corresponding to the injected bolus and the laryngeal framework were extracted and processed with MATLAB routines to generate selective 3D reconstructions of the injected bolus within the laryngeal framework. Histology analysis was also performed to correlate with observations from the 3D reconstructions. Results Boluses injected into the lateral aspect of the thyroarytenoid muscle tended to be irregularly shaped, appeared to fill up the paraglottic space, and were associated with significant muscle compression. The vertical thickness of the injected boluses averaged 9.5 mm for lateral boluses and 7.6 mm for medial boluses, which were comparable to the vertical thickness of uninjected vocal folds. Conclusion Laterally injected boluses are shaped by spatial constraints imposed by elements of the laryngeal framework. Compression of vocal fold muscle may be a mechanism accounting for stiffness from overinjection. The irregular shapes of some boluses may affect the outcome of subsequent medialization attempts. Injections may enhance the vocal fold contact height as a favorable effect beyond simple medialization.