Protection apparatus for implantable medical device

#This invention relates generally to a method and apparatus for use with an electronic implantable medical device for protecting the device from physical and/or electrostatic discharge damage prior to medically implanting the device in a patient's body. Moreover, preferred embodiments of the invention afford the ability to functionally test the device without removing it from its sterilized shipping container prior to implantation.

#Many types of electronic medical devices are known which are intended for implantation in a patient's body. Although these devices vary widely in design, they typically include a housing containing electronic circuitry connected to two or more electrodes which extend exteriorly from the housing (or one or more electrodes when the housing is the other electrode). The circuitry can, for example, include a functional circuit (e.g., a pulse generator), a power supply circuit (e.g., rechargeable battery), and a transceiver for wirelessly communicating with an external controller. Implantable medical devices of this sort are useful in a variety of applications for stimulating muscle or nerve tissue and/or monitoring body parameters. See, for example, U.S. Pat. Nos. 6,164,284; 6,185,452; 6,208,894; 6,315,721; and 6,472,991; which primarily relate to such devices that are battery powered, each of which is incorporated by reference herein in their entirety. Also see, for example, U.S. Pat. Nos. 5,193,539; 5,193,540; 5,312,439; 5,324,316; and 5,405,367; which primarily relate to such devices that are RF powered, each of which is incorporated by reference herein in their entirety.

#To minimize device failure and maximize device reliability, it is important that an electronic medical device be properly handled along the entire chain from manufacturing, through shipping and storage, and on to the medical procedure for implanting the device in a patient's body. For example, improper handling can subject the device to physical damage and/or component damage due to electrostatic discharge (ESD).

#FIG. 1 schematically depicts the structure of an exemplary electronic implantable medical device of the type intended for use with the present invention.

#FIG. 2 is a block diagram generally representing the electronic circuitry typically employed in the exemplary medical device of FIG. 1.

#FIG. 3 schematically depicts the exemplary medical device of FIG. 1 used in combination with a protection apparatus in accordance with the present invention.

#Attention is initially directed to FIG. 1 which schematically depicts an electronic implantable medical device 20. The device 20 is intended to be representative of a wide range of known electronic devices designed to be medically implanted in a patient's body for a variety of applications. For example only, such devices can be controlled to selectively stimulate muscle and nerve tissue and/or monitor and report various body parameters. The exemplary device 20 is depicted as comprising an elongate housing 22 defined by a peripheral wall 24 enclosing an interior volume 26. The housing 22 can be variously shaped but, for simplicity herein, it will be assumed to be cylindrical. Typically such implantable medical devices are small in size, e.g., preferably having an axial dimension of less than 60 mm and a lateral dimension of less than 6 mm, and relatively fragile structurally. See, for example, U.S. Pat. Nos. 6,164,284; 6,185,452; 6,208,894; 6,315,721; and 6,472,991; which primarily relate to such devices that are battery powered, each of which is incorporated by reference herein in their entirety. Also see, for example, U.S. Pat. Nos. 5,193,539; 5,193,540; 5,312,439; 5,324,316; and 5,405,367, which primarily relate to such devices that are RF powered, each of which is incorporated by reference herein in their entirety. Reasonable care must be exercised in handling the devices 20 to prevent physical damage.

#The exemplary device 20 is depicted as containing electronic circuitry 30 within the interior volume 26. The circuitry 30 is connected between first and second electrodes 32, 34 which extend exteriorly from the housing 22. The circuitry 30 typically includes sensitive electronic components which can be permanently damaged by high currents which can be caused, for example, by electrostatic discharge (ESD). Accordingly, as with many other electronic devices, it is advisable to exercise appropriate care to avoid discharging high currents through the circuitry 30. The present invention is primarily directed to a method and apparatus as depicted in FIGS. 3-15, for protecting the device 20, from damage while being shipped, stored, and handled between a late manufacturing stage and up to the time it is implanted in a patient's body.

#FIG. 2 is a block diagram which generally depicts the functional components of typical electronic circuitry 30 employed in an implantable medical device 20. More particularly, the electronic circuitry 30 is shown as comprising a power supply 38 which may include a rechargeable battery or a capacitor (not shown). A charging circuit 40 is connected to the power supply 38 for deriving energy from an external power source to charge the battery. For example only, the charging circuit 40 can respond to an alternating, e.g., amplitude modulated or frequency modulated, magnetic field or RF field to supply a charging current to the power supply 38. The power supply 38 is depicted as supplying an operating voltage to a transceiver circuitry 42 and a pulse generator 44. The transceiver circuitry 42 is configured to communicate with an external controller (not shown) employing a suitable form of wireless communication via path 43, typically radio communication. Commands and data can be supplied via path 43 from the external controller to the transceiver circuitry 42 for controlling or programming the pulse generator 44. The pulse generator 44 can in turn provide data to the transceiver circuit 42 via path 45 for communication to the external controller.