In a rare case of simultaneous glottic and supraglottic webbing a tantalum keel, as described by McNaught, and a silicone elastomer keel, as described by Montgomery, were placed simultaneously via laryngofissure.
Use of different materials appeared to have no bearing on the final, successful outcome.
Lauren D. Holinger, Herbert W. Wong, William G. Hemenway. Simultaneous Glottic and Supraglottic Laryngeal WebsReport of a Case. Arch Otolaryngol. 1975;101(8):496–497. doi:10.1001/archotol.1975.00780370038014