中耳しん出液排出用電動式マイクロポンプの開発

Abstract

For the treatment of otitis media with effusion, aspiration of fluid through a suction tube is conventionally performed after puncture or myringotomy. However, hypertrophy scars and sclerosis of the tympanic membrane can occur when the radial fiber bundles are cut by myringotomy. It is also very difficult to aspirate the hyperviscous fluid. We thus developed a micropump for use with a small caliber needle to avoid unnecessary injuries to the tympanic membrane. It is also equipped to mechanically transport viscous fluid.The micropump is composed of a motor and needle to puncture the tympanic membrane. Two spiral helical wires inside the needle which are connected to the airspindle (first model) or electric (second model) rotation machine rotate to remove even highly viscous fluid. We used standard viscosity oil to test the relationship between the viscosity of fluid and removal speed. We found that the faster the rotation, the quicker the removal of fluid, independent of viscosity. We confirmed the clinical usefulness of the new micropump and needle system for otitis media with effusion because the puncture needle is fine enough to perform a minimally invasive puncture of the tympanic membrane.We treated 16 patients (19 ears) with otitis media with effusion using this electric micropump between October 2000 and April 2001. In 15 ears, effusion was removed successfully, in 2 ears, we almost totally removed the effusion with very little residual fluid, and in 2 ears we could not remove the effusion due to the extremely high viscosity.