NA Shirwany, MD Seidman, W Tang, (Henry Ford Health System, Detroit)
Effect of Transtympanic Injection of Steroids on Cochlear Blood Flow, Auditory Sensitivity, and Histology in the Guinea Pig.
Am J Otol 19:230-235, 1998.
Steroids are usually administered parenterally or orally. There is evidence of significantly higher levels of steroid in the perilymph, after transtympanic injection. In the latter mode of administration, systemic side effects of steroids are avoided.
The effect of transtympanic injection of dexamethasone on cochlear blood flow, auditory sensitivity, and histologic effects in the guinea-pig were examined. The findings indicate that transtympanic administration of steroids does NOT damage the inner ear. The increase in cochlear blood flow was sustained for at least one hour after application of the drug.
HH Wanamaker, L Gruenwald, KJ Damm, et al (syracuse Univ, NY; Yamaguchi Univ, Japan).
Dose-related Vestibular and Cochlear Effects of Transtympanic Gentamicin.
Am J Otol 19:170-179, 1998.
A gerbil model used to test the relative cochlear and vestibular effects of transtympanically injected gentamicin, showed overall ototoxicity rather than selective vestibulotoxicity. Increase in the number of injections resulted in increased damage.
Gentamicin treatment to achieve vestibular ablation, also induces cochlear damage and associated hearing loss.