Utility of basic fibroblast growth factor in the repair of blast-induced total or near-total tympanic membrane perforations: A pilot study.

OBJECTIVE: A pilot study was performed to investigate the utility of basic fibroblast growth factor (bFGF) in the repair of blast-induced total or near-total tympanic membrane perforations (TMPs). STUDY DESIGN: Prospective clinical study. SETTING: Tertiary university hospital. SUBJECTS AND METHODS: Patients who fulfilled the inclusion criteria were treated with 0.10-0.15 mL of bFGF solution applied directly to total or near-total TMPs once daily until the perforations closed or for a maximum of 6 months. The treatment response was monitored via serial otoendoscopy, and audiometric outcomes were evaluated. RESULTS: Complete TMP closure was achieved in 16 of 17 patients with a blast-induced total or near-total TMP. The mean closure time was 28.4 ± 10.9 days. The improvement in hearing from pre- to post-treatment was statistically significant. There were no complications or adverse outcomes. CONCLUSIONS: The direct application of bFGF to blast-induced total or near-total TMPs is a promising, minimally invasive alternative to conventional tympanoplasty, with a comparable success rate. As reported in the literature, the closure rate was higher than achieved with spontaneous healing. There was no effect of the inverted edge on healing outcome. The use of bFGF in this setting has immediate therapeutic applications for military personnel with blast-induced TMPs who are stationed in isolated, remote environments.

Performance considerations of prosthetic actuators for round-window stimulation.

Round-window (RW) stimulation has improved speech perception in patients with mixed hearing loss. In cadaveric temporal bones, we recently showed that RW stimulation with an active prosthesis produced differential pressure across the cochlear partition (a measure related to cochlear transduction) similar to normal forward sound stimulation above 1 kHz, when contact area between the prosthesis and RW is secured. However, there is large variability in the hearing improvement in patients implanted with existing modified prosthesis. This is likely because the middle-ear prosthesis used for RW stimulation was designed for a very different application. In this paper, we utilize recently developed experimental techniques that allow for the calculation of performance specifications for a RW actuator. In cadaveric human temporal bones (N=3), we simultaneously measure scala vestibuli and scala tympani intracochlear pressures, as well as stapes velocity and ear-canal pressure, during normal forward sound stimulation as well as reverse RW stimulation. We then calculate specifications such as the impedance the actuator will need to oppose at the RW, the force with which it must push against the RW, and the velocity and distance by which it must move the RW to obtain cochlear stimulation equivalent to that of specific levels of ear-canal pressure under normal sound stimulation. This information is essential for adapting existing prostheses and for designing new actuators specifically for RW stimulation.