Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical therapeutic systems
Reexamination Certificate
2000-02-29
2002-08-06
Layno, Carl (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical therapeutic systems
C607S038000
Reexamination Certificate
active
06430442
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to implantable medical devices for the human body, for electrical stimulation to the spinal cord and peripheral nervous system. More specifically, the invention relates to the mechanical and electrical connection of leads, extension cables, and implantable pulse generators in such implantable medical devices.
Briefly, APT Neurostimulation (“Advanced Pain Therapy Neurostimulation”) is available from Medtronic, Inc., and commonly used for neuropathic pain. APT Neurostimulation, used for both spinal cord stimulation and peripheral nerve stimulation, uses a small neurostimulation system that is surgically placed under the skin to send mild electrical impulses to the spinal cord or nerves. The electrical impulses are delivered through a lead that is also surgically placed, near the spinal cord or the nerve selected to be stimulated. These electrical impulses block signals of pain from reaching the brain. Medtronic APT Neurostimulation systems include the Itrel® 3 system, consisting of an implantable pulse generator (IPG), a patient programmer, an extension, a lead(s), and a connector block. This system is totally implantable—no part is outside the body. The IPG generates precise, electrical pulses to control pain. The IPG contains a special battery and electronics to create these pulses. The unit, which is about 2.25 inches (6 cm) across, less than one-half inch (1 cm) thick and about 2 inches (5.2 cm) high, is most often placed under the skin of the abdomen. The lead is a small medical wire with special insulation. It commonly has four or eight electrodes, small, exposed electrical contacts, through which electrical stimulation is delivered. It also commonly has a corresponding four or eight internal wires for separate electrical connection to each electrode, for selective use of the electrodes in providing stimulation. The lead is placed such that the electrodes are next to the spinal cord or peripheral nerve to be stimulated. The extension is a small cable about 20 inches (50 cm) long that is placed under the skin and connects the lead to the IPG.
In addition to treating pain, Medtronic devices assist patients with other concerns. The Medtronic InterStim® Therapy for Urinary Control offers an approach for managing urinary urge incontinence, nonobstructive urinary retention, and significant symptoms of urgency-frequency in patients who have failed or could not tolerate more conservative treatments. The implantable InterStim Therapy system uses mild electrical stimulation of the sacral nerves, in the lower region of the spine, that influence the behavior of the bladder, sphincter, and pelvic floor muscles. As with APT Neurostimulation, a lead is surgically implanted, an extension runs to a neurostimulator, and the neurostimulator acts as an IPG to send precise, electrical pulses to your sacral nerves to control the treated symptoms.
In variations of these devices, alternate systems include devices that are implanted, along with devices that are external such as accessories for increased battery life.
To date, the electrical and mechanical connections of the lead to the extension in neurological implants are accomplished by a connector block including a series of set screw blocks. Leads are inserted in metal set screw blocks, and metal set screws press against proximal ring contacts on the leads and press the contacts against the blocks, to clamp them in place and cause electrical connection between the lead wires and the blocks. U.S. Pat. No. 5,458,629 issued Oct. 17, 1995, to Baudino, for an Implantable Lead Ring Electrode and Method of Making, briefly describes the connector blocks and associated lead structure, at column 4, lines 5-16, and that description is incorporated by reference.
SUMMARY OF THE INVENTION
A primary object of the invention is to substantially advance the construction and method employed for connecting leads, extensions and IPGs in the connector blocks of neurological implants.
Another primary object is to minimize the need for set screws in connector blocks for placing leads in the human body for spinal cord and peripheral nerve stimulation. Most preferably, the connection of leads, extensions, and IPGs becomes “tool-less.”
Other primary objects include substantially reducing the times and physical efforts required of surgeons for connecting leads and connector blocks, and reducing the lengths of implantation surgeries, while maintaining the substantial benefits that flow from excellent electrical and mechanical connection of leads, extensions and IPGs.
In a principal aspect, the invention is incorporated in body implantable apparatus for implantation in a living human body, for delivering electrical stimulation to at least one nerve of the body, where the apparatus includes an implantable pulse generator (IPG), for generating the electrical stimulation, and an implantable wire-like electrical lead for delivering the stimulation from the IPG to the desired site of stimulation. The lead is of the type having a distal portion for placement at the site and a proximal portion, the proximal portion including multiple proximal electrical contacts on its surface. In this environment, the invention is an improved connector block for electrical and mechanical connection of the proximal portion of the lead into the apparatus, for example, by connection to an extension. The improved connector block comprises a plurality of multi-piece bodies each forming a receptor opening for a proximal electrical contact, at least one of the body pieces of each body being electrically conductive adjacent the receptor opening. A plurality of elastic members each retain together the body pieces of one of the multi-piece bodies, bias the body pieces into mechanical, fixating contact with a proximal electrical contact, and bias the electrically conductive body piece into electrical contact with the proximal electrical contact, when the proximal electrical contact is introduced into the receptor opening. The elastic member is, further, elastically yieldable under mechanical force to permit introduction of the proximal electrical contact into the receptor opening.
In another principal aspect, and more generally, the invention includes an improvement in body implantable apparatus for implantation in a living body, for delivering electrical stimulation to the nervous system of the body, the apparatus including a wire-like electrical conductor. In this aspect, the invention takes the form of an improved electrical and mechanical connector for the conductor. This connector comprises at least two components. First, a multi-piece body forms a receptor for the conductor. At least one of the body pieces is electrically conductive. Second, an elastic member retains together the body pieces of the multi-piece body. The elastic member biases the body pieces into mechanical, restraining contact with the conductor, and biases the electrically conductive body piece into electrical contact with the conductor, when the conductor is introduced into the receptor. The elastic member further elastically yields under mechanical force to permit introduction of the conductor into the receptor. The conductor may be a lead, an extension, or other perhaps similar electrical conductor.
As preferred, the multi-piece body includes multiple duplicate pieces arranged circumferentially around the receptor, most preferably two such pieces, both electrically conductive. In this construction, the elastic member circumferentially retains together the body pieces. The multi-piece body forming the receptor for the conductor consists of two arcuate, duplicate pieces arranged circumferentially around the receptor. Also as most preferred, the arcuate pieces of the multi-piece body have conical insertion guiding surfaces, sloped inwardly toward the center of the pieces, on both sides of the center. Further as most preferred, the elastic member includes a superelastic material, such as nickel titanium alloy, and the member is C-shaped and positioned in a groove around the body pi
Christenson James J.
Peters Charles E.
Layno Carl
Medtronic Inc.
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