Suitability of the partially implantable active middle-ear amplifier Vibrant Soundbridge® to hyperbaric exposure.

INTRODUCTION

Active middle ear amplifiers represent a modern possibility to treat sensorineural, conductive and combined hearing loss. They can be in use in divers and patients who need hyperbaric oxygen therapy. Therefore, active middle-ear amplifiers have to be tested to determine whether or not they are prone to implosion or function loss in hyperbaric conditions.

MATERIAL AND

METHODS

We asked three of the companies registered by the German health authorities as manufacturers of active middle ear amplifiers to test their devices in hyperbaric conditions. Med-El agreed to support the study; Envoy stated that their devices were unable to withstand a pressure of 608 kPa; Otologics had no capacity to take part in this study. Twelve Vibrant Soundbridge® (Med-El) middle-ear amplifiers were tested in a water bath in a hyperbaric chamber. Four devices were pressurised to a maximum of 284 kPa, four devices to 405 kPa and four devices to 608 kPa, each for a maximum dive time of 78 minutes.

RESULTS

The functions of the 12 devices were tested by the manufacturer pre- and post-hyperbaric exposure. Visual inspections as well as laboratory function tests were normal in all 12 devices after hyperbaric exposure.

DISCUSSION AND

CONCLUSION

Hyperbaric exposure to more than one bar pressure difference can result in structure damage, implosion or loss of function of the mechanical device. The Vibrant Soundbridge® middle-ear amplifier tolerated a single hyperbaric exposure to pressures of up to 608 kPa for 78 minutes with no loss of performance.