| abstract |
An implantable infusion device includes of a disc-shaped housing that is made from a biocompatible material. The housing contains a reservoir for holding a volume of infusion medium, such as a medication to be administered to the patient. A reservoirs for an implantable infusion devices may be configured to reduce the thickness requirements of the device, without compromising volume capacity of the device. In addition, such a reservoir configuration can allow multiple dispensing and fill or re-fill operations, with reduced risk of damage to the reservoir components. The reservoir defines a chamber that contains at least one flexible diaphragm. Each diaphragm has an outer peripheral edge within the chamber, a convolution adjacent the peripheral edge and a generally smooth central portion that is free to flex within the chamber, wherein the convolution enhances the flexibility of the diaphragm. A ring is provided in alignment with the peripheral edge of each diaphragm. The ring has a central opening that is aligned with the convolution and central portion of each diaphragm, to allow the diaphragm to flex within the ring. In this manner, the volume on one side of each diaphragm may be varied to correspond to a varying volume of infusion medium. Similarly, the volume within the reservoir chamber on the other side of the diaphragms is varied as the diaphragms flex, to correspond to the expansion and contraction of a propellant medium within the reservoir. |