US20070032836A1

US20070032836A1 - Percutaneous electrode assemblies, systems, and methods for providing highly selective functional or therapeutic neuromuscular stimulation

Info

Publication number: US20070032836A1
Application number: US11/545,336
Authority: US
Inventors: Geoffrey Thrope; Robert Strother; Joseph Mrva
Original assignee: NDI Medical LLC
Current assignee: NDI Medical LLC
Priority date: 2004-02-12
Filing date: 2006-10-10
Publication date: 2007-02-08
Also published as: US20100100158A1; US7120499B2; WO2005081740A2; US20050182455A1; US7571002B2; US20070032837A1; WO2005081740A3

Abstract

Percutaneous electrode assemblies, systems, and methods make possible the providing of short-term therapy or diagnostic testing by providing electrical connections between muscles or nerves inside the body and stimulus generators or recording instruments carried outside the body. The percutaneous electrodes include a flexible body having an electrically conductive region, a tissue penetrating region, and a percutaneous lead electrically coupled to the electrically conductive region. An anchoring element is positioned on the flexible body to resist movement of the electrically conductive region within tissue. An introducer is sized and configured to receive the flexible body and shield the anchoring element from contact with tissue while the electrically conductive region is placed to a desired position within tissue, and accommodates advancement of the anchoring element beyond the interior lumen for contact with tissue to resist movement of the electrically conductive region placed in the desired position.

Description

RELATED APPLICATION

This application is a divisional application of U.S. patent application Ser. No. 10/777,771, filed 12 Feb. 2004, and entitled “Portable Percutaneous Assemblies, Systems, and Methods for Providing Highly Selective Functional Therapeutic Neuromuscular Stimulation.”

FIELD OF INVENTION

This invention relates to percutaneous electrode systems and methods for providing neuromuscular stimulation.

BACKGROUND OF THE INVENTION

Neuromuscular stimulation can perform functional and/or therapeutic outcomes. While existing systems and methods can provide remarkable benefits to individuals requiring neuromuscular stimulation, many quality of life issues still remain. For example, existing systems perform a single, dedicated stimulation function. Furthermore, these controllers are, by today's standards, relatively large and awkward to manipulate and transport.
It is time that systems and methods for providing neuromuscular stimulation address not only specific prosthetic or therapeutic objections, but also address the quality of life of the individual requiring neuromuscular stimulation.

SUMMARY OF THE INVENTION

The invention provides improved percutaneous electrode assemblies, systems, and methods for providing prosthetic or therapeutic neuromuscular stimulation.
One aspect of the invention provides portable, percutaneous neuromuscular stimulation assemblies, systems and methods that provide electrical connections between muscles or nerves inside the body and stimulus generators or recording instruments temporarily mounted on the surface of the skin outside the body. The assemblies, systems, and methods are, in use, coupled by percutaneous leads to electrodes, which are implanted below the skin surface in a targeted tissue region or regions. The neuromuscular stimulation assemblies, systems, and methods apply highly selective patterns of neuromuscular stimulation only to the targeted region or regions, to achieve one or more highly selective therapeutic and/or diagnostic outcomes. The patterns can vary according to desired therapeutic and/or diagnostic objectives. The indications can include, e.g., the highly selective treatment of pain or muscle dysfunction, and/or the highly selective promotion of healing of tissue or bone, and/or the highly selective diagnosis of the effectiveness of a prospective functional electrical stimulation treatment by a future, permanently implanted device.
The neuromuscular stimulation assemblies, systems, and methods comprise a skin-worn patch or carrier. The carrier can be readily carried, e.g., by use of a pressure-sensitive adhesive, without discomfort and without affecting body image on an arm, a leg, or torso of an individual.
The carrier carries an electronics pod, which generates the desired electrical current patterns. The pod houses microprocessor-based, programmable circuitry that generates stimulus currents, time or sequence stimulation pulses, and logs and monitors usage. The electronics pod also includes an electrode connection region, to physically and electrically couple percutaneous electrode leads to the circuitry of the electronics pod.
The carrier further includes a power input bay, to receive a small, lightweight, primary cell battery, which can be released and replaced as prescribed. The battery provides power to the electronics pod.
It is contemplated that, in a typical regime prescribed using the neuromuscular stimulation assemblies, systems, and methods, an individual will be instructed to regularly remove and discard the battery (e.g., about once a day or once a week), replacing it with a fresh battery. This arrangement simplifies meeting the power demands of the electronics pod. The use of the neuromuscular stimulation assemblies, systems, and methods thereby parallels a normal, accustomed medication regime, with the battery being replaced at a prescribed frequency similar to an individual administering a medication regime in pill form.
The power input bay can also serve as a communication interface, to be plugged into a mating communications interface on an external device. Through this link, a caregiver or clinician can individually program the operation of a given electronics pod.
The assemblies, systems, and methods make possible many different outcomes, e.g., (i) acute pain relief through treatment of pain or muscle dysfunction via the application of electrical stimulation to muscles (or their enervating nerves) with compromised volitional control due to injury to the peripheral or central nervous system (e.g., limb trauma, stroke, central nervous system diseases, etc.); and/or (ii) maintenance of muscle function and prevention of disuse atrophy through temporary stimulation to maintain muscle strength, mass, peripheral blood flow, etc., following a temporary disruption of function by disease or injury; and/or (iii) enhanced tissue and bone regeneration through the provision of small DC currents (or very low frequency AC currents) in bone or tissue to aid or speed healing of bone unions, tissue re-growth, etc; and/or (iv) treatment of pain or other conditions through the application of nerve stimulation to provide a neuromodulation or inhibitory effect; and/or (v) post-surgical reconditioning to enhance muscle function and promote recovery of strength post-operatively; and/or (vi) anti-thrombosis therapy, e.g., by the stimulation of leg muscles to increase venous return of blood; and/or (vii) the treatment of osteoporosis by cyclic stimulation of muscles; and/or (viii) the short-term provision of electrical stimulation to evaluate the effectiveness of such treatment in advance of the implantation of a more permanent implant; and/or (ix) the short-term recording of biopotential signals generated in the body to aid in the diagnosis of medical conditions or in the assessment of the effectiveness of treatment methods.
Another aspect of the invention provides systems and methods for implanting a percutaneous electrode having an electrically conductive region. The systems and methods provide a percutaneous electrode with an anchoring element to resist movement of the percutaneous electrode within tissue. The systems and methods insert the percutaneous electrode through skin and tissue housed within an introducer, which shields the anchoring element from contact with tissue. The introducer may include an electrically isolated area that corresponds to the electrically conductive region of the electrode. The electrically isolated area may then be electrically coupled to a connector on the introducer to allow the electrically isolated area to be coupled to a stimulating circuit.
The systems and methods implant the percutaneous electrode while inserted within the introducer, to place the percutaneous electrode in a desired location within tissue, but without placing the anchoring element in contact with tissue. The systems and methods withdraw the introducer to place the anchoring element in contact with tissue, thereby resisting movement of the percutaneous electrode from the desired position. The systems and methods may also include, during the implanting step, a step of coupling the percutaneous electrode to a stimulating circuit to provoke a tissue stimulation response to place the percutaneous electrode in the desired location. Or, during the implanting step, the systems and methods may also include a step of coupling the introducer to a stimulating circuit to provoke a tissue stimulation response to place the percutaneous electrode in the desired location.
One aspect of the invention provides a flexible body that is sized to have a diameter not greater than about 0.5 mm, and an anchoring element that comprises a barb.
Yet another aspect of the invention provides a percutaneous electrode assembly having a flexible body including one or more electrically conductive regions, a tissue penetrating region for implantation of the electrically conductive regions in a targeted tissue region, and a percutaneous lead electrically coupled to the electrically conductive regions, the lead including a conductor for each electrically conductive region. An anchoring element is positioned on the flexible body to resist movement of the electrically conductive region within tissue. A flexible introducer that has an interior lumen is sized and configured to receive the flexible body and shield the anchoring element from contact with tissue while the electrically conductive region is placed to a desired position within tissue. The flexible introducer is also sized and configured to accommodate advancement of the anchoring element beyond the interior lumen for contact with tissue to resist movement of the electrically conductive region placed in the desired position. The flexible introducer may also be sized and configured to accommodate advancement of the flexible body and anchoring element beyond the interior lumen while the flexible introducer is bent.
Other features and advantages of the inventions are set forth in the following specification and attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a neuromuscular stimulation assembly that provides electrical connections between muscles or nerves inside the body and stimulus generators temporarily mounted on the surface of the skin outside the body.
FIG. 2 is a view of the neuromuscular stimulation assembly shown in FIG. 1 worn on a temporary basis on an external skin surface of an arm.
FIG. 3 is an exploded side view of the neuromuscular stimulation assembly shown in FIG. 1, showing its coupling to percutaneous leads to electrodes, which are implanted below the skin surface in a targeted tissue region or regions.
FIGS. 4A and 4B are perspective views of an electronics pod that is associated with the neuromuscular stimulation assembly shown in FIG. 1, which is capable of being docked within an electronics bay in the neuromuscular stimulation assembly for use, with FIG. 4A showing the pod in a closed condition for docking with neuromuscular stimulation assembly, and FIG. 4B showing the pod in an opened condition for receiving electrode leads prior to docking with the neuromuscular stimulation assembly.
FIG. 5 is a perspective view of an electronics pod as shown in FIG. 4A docked within an electronics bay in a neuromuscular stimulation assembly for use, showing the power input bay opened and empty to enable visual inspection of underling skin.
FIG. 6 is a perspective view of the electronics pod shown in FIG. 4B in an opened condition on a skin surface preliminary to placement of percutaneous electrodes.
FIGS. 7 and 8 show the implantation of a first percutaneous electrode (FIG. 7) and the routing of its percutaneous electrode lead into an electrode connection region on pod (FIG. 8).
FIG. 9 shows the presence of second, third, and fourth percutaneous electrodes that have been sequentially implanted and the routing of their percutaneous electrode leads into the electrode connection regions on the pod, while the pod remains in the opened condition.
FIG. 10 shows the pod shown in FIG. 9, after having been placed in a closed condition, ready for use.
FIG. 11 shows the pod shown in FIG. 10, after having been docked within an electronics bay in the neuromuscular stimulation assembly for use.
FIGS. 12A and 12B are perspective views of an alternative embodiment of a neuromuscular stimulation assembly, which includes an integrated electronics pod, with FIG. 12A showing the neuromuscular stimulation assembly in a closed condition for use, and FIG. 12B showing the neuromuscular stimulation assembly in an opened condition for receiving electrode leads prior to use.
FIG. 13 is a perspective view of a neuromuscular stimulation assembly of the type shown in FIG. 1 coupled to an external programming instrument.
FIGS. 14 to 16 show the use of an electrode introducer to percutaneously implant an electrode in the manner shown in FIGS. 6 and 7 for connection to a neuromuscular stimulation assembly as shown in FIG. 11.
FIG. 17 is a perspective view of a neuromuscular stimulation system comprising a neuromuscular stimulation assembly of the type shown in FIG. 1 in association with a prescribed supply of replacement batteries and instructions for using the a neuromuscular stimulation assembly, including the recharging of the neuromuscular stimulation therapy by inserting a fresh battery, just as an individual on a medication regime “recharges” their medication therapy by taking a pill.
The invention may be embodied in several forms without departing from its spirit or essential characteristics. The scope of the invention is defined in the appended claims, rather than in the specific description preceding them. All embodiments that fall within the meaning and range of equivalency of the claims are therefore intended to be embraced by the claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The various aspects of the invention will be described in connection with providing functional neuromuscular stimulation for prosthetic or therapeutic purposes. That is because the features and advantages that arise due to the invention are well suited to this purpose. Still, it should be appreciated that the various aspects of the invention can be applied to achieve other objectives as well.
I. Neuromuscular Stimulation Assembly 10
A. Overview
FIG. 1 shows a neuromuscular stimulation assembly 10. As FIG. 2 shows, the neuromuscular stimulation assembly 10 is sized and configured so that, in use, it can be conveniently worn on a temporary basis on an external skin surface. By “temporary,” it is meant that the presence of the neuromuscular stimulation assembly 10 can be well tolerated without discomfort for a period of time from several hours to a month or two, after which the neuromuscular stimulation assembly 10 can be removed and discarded.
As FIG. 3 shows, the neuromuscular stimulation assembly 10 is, in use, releasably coupled by percutaneous leads 12 to electrodes 14, which are implanted below the skin surface in a targeted tissue region or regions. The tissue region or regions are targeted prior to implantation of the electrodes 14 due to their muscular and/or neural morphologies in light of desired therapeutic and/or functional and/or diagnostic objectives.
In use, the neuromuscular stimulation assembly 10 generates and distributes electrical current patterns through the percutaneous leads 12 to the electrodes 14. In this way, the neuromuscular stimulation assembly 10 applies highly selective patterns of neuromuscular stimulation only to the targeted region or regions, to achieve one or more highly selective therapeutic and/or diagnostic outcomes. As will be described in greater detail later, the inputs/stimulation parameters can vary according to desired therapeutic and/or diagnostic objectives. For example, the outcomes can comprise the highly selective treatment of pain or muscle dysfunction, and/or the highly selective promotion of healing of tissue or bone, and/or the highly selective diagnosis of the effectiveness of a prospective functional electrical stimulation treatment.
B. The Carrier
In its most basic form (see FIGS. 1 and 3), the neuromuscular stimulation assembly 10 comprises a patch or carrier 16. The carrier 16 desirably is sized and configured as a compact, lightweight housing made, e.g., of an inert, formed or machined plastic or metal material.
In a desired implementation, the carrier 16 approximates the geometry of the face of a wrist watch, measuring, e.g., about 1 inch in diameter, weighing, e.g., about 5 g. At this size, the carrier 16 can be readily worn without discomfort and in a cosmetically acceptable way (as FIG. 2 shows). The carrier 16 physically overlays and protects the site where the percutaneous electrode leads 12 pass through the skin.
Within its compact configuration, the carrier 16 includes several functional components, which will now be described.
C. The Adhesive Region
At least a portion of the undersurface of the carrier 16 (see FIGS. 1 and 3) includes an adhesive region 18. The function of the adhesive region 18 is to temporarily secure the carrier 16 to an external skin surface during use. For example, an inert, conventional pressure sensitive adhesive can be used. Desirably, the adhesive region contains a bacteriostatic sealant that prevents skin irritation or superficial infection, which could lead to premature removal.
The adhesive region 18 can also include an electrically conductive material. In this arrangement, the adhesive region 18 can serve as a return electrode, so that monopolar electrodes 14 can be implanted, if desired.
D. The Electronics Pod
The carrier 16 further carries an electronics pod 20, which generates the desired electrical current patterns.
As FIG. 3 shows, the electronics pod 20 can comprise a component that can be inserted into and removed from an electronics bay 22 in the carrier 16. Having an electronics pod 20 that can be separated from the carrier 16 may be desired when the need to replace a carrier 16 during a course of treatment is necessary. For example, replacement of a carrier 16 without replacement of the electronics pod 20 may be desired if the anticipated length of use of the neuromuscular stimulation assembly 10 is going to be long enough to expect a degradation of adhesive properties of the adhesive region 18, or when the adhesive region 18 serves as a return electrode and may undergo, with use, degradation of adhesive properties and/or electrical conductivity.
Alternatively, as FIGS. 12A and 12B show, the electronics pod 20 can comprise an integral, non-removable part of the carrier 16.
Regardless of whether the electronics pod 20 is removable from the carrier 16 (FIGS. 4A and 4B) or not (FIGS. 12A and 12B), the pod 20 houses microprocessor-based circuitry 24 that generates stimulus currents, time or sequence stimulation pulses, and logs and monitors usage. The circuitry 24 desirably includes a flash memory device or an EEPROM memory chip to carry embedded, programmable code 26. The code 26 expresses the preprogrammed rules or algorithms under which the stimulation timing and command signals are generated. The circuitry 24 can be carried in a single location or at various locations on the pod 20.
E. The Electrode Connection Region
As FIGS. 4A/4B and FIGS. 12A/12B show, the electronics pod 20 also includes an electrode connection region 28. The function of the electrode connection region 28 is to physically and electrically couple the terminus of the percutaneous electrode leads 12 to the circuitry 24 of the electronics pod 20 (as FIG. 10 shows). The electrode connection region 28 distributes the electrical current patterns in channels—each electrode 14 comprising a channel—so that highly selective stimulation patterns can be applied through the electrodes 14. Four channels (numbered 1 to 4 on the pod 20) are shown in FIGS. 4A/4B and 12A/12B.
The electrode connection region 28 can be constructed in various ways. In the illustrated embodiments FIGS. 4A/4B and FIGS. 12A/12B), the electrode connection region 28 comprises troughs 30 formed in the electronics pod 20. Four troughs 30 are shown in FIGS. 4A/4B and FIGS. 12A/12B, each trough 30 being sized and configured to slidably receive the lead 12 of one electrode 12 in an interference fit (see FIG. 10). Each trough 30 is labeled with a number or other indicia to record the channel of the electronics circuitry 24 that is coupled to each trough 30.
Each trough 30 routes the terminus of an electrode lead 12 to a given channel (see FIG. 7), allowing the lead 12 to be stretched taut to become frictionally lodged within the trough 30. In FIGS. 4A/4B, the trough 30 includes at its end a mechanism 60 to displace or pierce the insulation of the lead and make electrical contact with the conductive wire of the lead 12. This mechanically secures the lead 12 while electrically coupling the associated electrode 14 with the circuitry 24 of the electronics pod 20.
In the illustrated embodiment, for ease of installation, the electronics pod 20 shown in FIGS. 4A and 4B comprises mating left and right pod sections 32 and 34 joined in a sliding fashion by rails 36. The pod sections 32 and 34 can be separated by sliding apart along the rails 36 to an opened condition, as shown in FIG. 4B. The pod sections 32 and 34 can brought together by sliding along the rails 36 to a closed condition, as shown in FIG. 4A. The electronics circuitry 24 is carried within one or both of the pod sections 32 and 34.
When in the opened position (see FIG. 6), the separated pod sections 32 and 34 expose a region 38 of underlying skin through which the electrodes 14 can be percutaneously implanted. The implantation of the electrodes 14 in this skin region 38 will be described in greater detail later. Opening of the pod sections 32 and 34 also makes the troughs 30 readily accessible for receipt and routing of the electrode leads 12 (see FIG. 8), which pass upward through the exposed skin region 38.
Closing of the pod sections 32 and 34 (see FIG. 10), captures the electrode leads 12 within the mechanisms 60 in electrical connection with the circuitry 24 of the electronics pod 20. When in the closed condition (as FIG. 10 shows), the pod sections 32 and 34 mate but still allow visual inspection of the underlying skin region 38 through which the electrode leads 12 pass. As FIG. 5 shows, visual inspection of the underlying skin region 28 through the pod 20 is still accommodated even after the carrier 16 is docked to the pod 20 (by viewing through an empty power input bay 40 of the carrier 16).
Desirably, closing of the pod sections 32 and 34 also cuts off excess lead wire at the end. Otherwise, the excess lead can be cut manually. At this time (see FIG. 11), a carrier 16 can be placed over the electronics pod 20, by snap-fitting the electronics pod 20 into an electronics bay 22 of the carrier 16. An electrical connection region or contact 62 on the pod 20 electrically couples to a mating connection region or contact on the carrier 16, to couple the circuitry 24 on the pod 20 to a power source 42 carried by the carrier 16.
It should be appreciated that, in an arrangement where the electronics pod 20 is an integrated part of the carrier 16 (as shown in FIGS. 12A and 12B), the carrier 16 itself can comprise the separable sections 32 and 34. In this arrangement, one carrier section 34 can include an adhesive region 18, which will adhere the carrier 16 to the skin in an opened condition to allow routing of the electrode leads 12. Upon closing the carrier sections 32 and 34, a pull-away strip 60 on the other carrier section 32 can be removed to expose another adhesive region to entirely secure the carrier 16 to the skin.
Alternative embodiments are possible. For example, a locking motion, coupling the electrode leads 12 to the electronics pod 20, can be accomplished by a button, or a lever arm, or an allen drive that is pushed, or slid, or pulled, or twisted.
F. The Power Input/Communication Bay
Referring back to FIG. 3, the carrier 16 further includes a power input bay 40. One function of the power input bay 40 is to releasably receive an interchangeable, and (desirably) disposable battery 42, e.g., an alkaline or lithium battery. The battery 42 provides power to the electronics pod 20. If desired (see FIG. 3), the power input bay 40 can include a hinged cover 44. FIG. 12B also shows the presence of a battery-receiving power input bay 40. Alternatively, the battery 42 might form the cover without a hinge using a snap-fit mechanism to secure the battery into the power input bay 40.
It is contemplated that, in a typical regime prescribed using the neuromuscular stimulation assembly 10, an individual will be instructed to remove and discard the battery 42 about once a day, replacing it with a fresh battery 42. This arrangement simplifies meeting the power demands of the electronics pod 20. The use of the neuromuscular stimulation assembly 10 will thereby parallel a normal, accustomed medication regime, with the battery 42 being replaced in the same frequency an individual administers medication in pill form. The battery 42 may be provided in an over-molded housing to ease attachment and removal.
The power input bay 40 can also serve as a communication interface. As FIG. 13 shows, when free of a battery 42, the bay 40 can be used to plug in a cable 58 to an external programming device 46 or computer. This will also be described later. This makes possible linking of the electronics pod 20 to an external programming device 46 or computer. Through this link, information and programming input can be exchanged and data can be downloaded from the electronics pod 20.
In this way, the neuromuscular stimulation assembly 10 makes it possible for a care giver or clinician to individually program the operation of a given electronics pod 20 to the extent permitted by the embedded, programmable code 26. It should be appreciated, of course, that instead of using a cable interface, as shown, a wireless link (e.g., RF magnetically coupled, infrared, or RF) could be used to place the electronics pod 20 in communication with an external programming device 46 or computer.
As FIG. 5 also shows, with the battery 42 removed and the cover (if any) opened, the underlying skin region 38, through which the percutaneous electrode leads pass, can be readily viewed through the power input bay 40.
G. The Electrodes and their Implantation
The configuration of the electrodes 14 and the manner in which they are implanted can vary. A representative embodiment will be described, with reference to FIGS. 14 to 16.
In the illustrated embodiment, each electrode 14 and lead 12 comprises a thin, flexible component made of a metal and/or polymer material. By “thin,” it is contemplated that the electrode 14 should not be greater than about 0.5 mm (0.020 inch) in diameter.
The electrode 14 and lead 12 can comprise, e.g., one or more coiled metal wires with in an open or flexible elastomer core. The wire can be insulated, e.g., with a biocompatible polymer film, such as polyfluorocarbon, polyimide, or parylene. The electrode 14 and lead 12 are desirably coated with a textured, bacteriostatic material, which helps to stabilize the electrode in a way that still permits easy removal at a later date and increases tolerance.
The electrode 14 and lead 12 are electrically insulated everywhere except at one (monopolar), or two (bipolar), or three (tripolar) conduction locations near its distal tip. Each of the conduction locations is connected to a conductor that runs the length of the electrode and lead, proving electrical continuity from the conduction location to the electronics pod 20. The conduction location may comprise a de-insulated area of an otherwise insulated conductor that runs the length of an entirely insulated electrode. The de-insulated conduction region of the conductor can be formed differently, e.g., it can be wound with a different pitch, or wound with a larger or smaller diameter, or molded to a different dimension. The conduction location of the electrode may comprise a separate material (metal or conductive polymer) exposed to the body tissue to which the conductor of the wire is bonded.
The electrode 14 and lead 12 desirably possess mechanical properties in terms of flexibility and fatigue life that provide an operating life free of mechanical and/or electrical failure, taking into account the dynamics of the surrounding tissue (i.e., stretching, bending, pushing, pulling, crushing, etc.). The material of the electrode desirably discourages the in-growth of connective tissue along its length, so as not to inhibit its withdrawal at the end of its use. However, it may be desirable to encourage the in-growth of connective tissue at the distal tip of the electrode, to enhance its anchoring in tissue.
Furthermore, the desired electrode 14 will include, at its distal tip, an anchoring element 48 (see FIGS. 15 and 16). In the illustrated embodiment, the anchoring element 48 takes the form of a simple barb. The anchoring element 48 is sized and configured so that, when in contact with tissue, it takes purchase in tissue, to resist dislodgement or migration of the electrode out of the correct location in the surrounding tissue. Desirably, the anchoring element 48 is prevented from fully engaging body tissue until after the electrode has been deployed. The electrode is not deployed until after it has been correctly located during the implantation (installation) process, as will be described in greater detail later.
In one embodiment, the electrode 14 and lead 12 can include a metal stylet within its core. Movement of the stylet with respect to the body of the electrode and/or an associated introducer (if used) is used to deploy the electrode by exposing the anchoring element 48 to body tissue. In this arrangement, the stylet is removed once the electrode 14 is located in the desired region.
In the illustrated embodiment (see FIGS. 14 and 15), each electrode 14 is percutaneously implanted housed within electrode introducer 50. The electrode introducer 50 comprises a shaft having sharpened needle-like distal tip, which penetrates skin and tissue leading to the targeted tissue region. The electrode 14 and lead 12 are loaded within a lumen in the introducer 50, with the anchoring element 48 shielded from full tissue contact within the shaft of the introducer 50 (see FIG. 14). In this way, the introducer can be freely manipulated in tissue in search of a desired final electrode implantation site (see FIG. 14) before deploying the electrode (see FIG. 15) and withdrawing the introducer 50 (see FIG. 16).
The electrode introducer 50 is insulated along the length of the shaft, except for those areas that correspond with the exposed conduction surfaces of the electrode 14 housed inside the introducer 50. These surfaces on the outside of the introducer 50 are electrically isolated from each other and from the shaft of the introducer 50. These surfaces are electrically connected to a connector 64 at the end of the introducer body (see FIGS. 14 and 15). This allows connection to a stimulating circuit 66 (see FIG. 14) during the implantation process. Applying stimulating current through the outside surfaces of the introducer 50 provides a close approximation to the response that the electrode 14 will provide when it is deployed at the current location of the introducer 50.
The electrode introducer 50 is sized and configured to be bent by hand prior to its insertion through the skin. This will allow the physician to place an electrode 14 in a location that is not in an unobstructed straight line with the insertion site. The construction and materials of the electrode introducer 50 allow bending without interfering with the deployment of the electrode 14 and withdrawal of the electrode introducer 50, leaving the electrode 14 in the tissue.
II. Installation of the Neuromuscular Stimulation
Assembly
Prior to installation, a clinician identifies a particular muscle and/or neural region to which a prescribed therapy using a neuromuscular stimulation assembly 10 will be applied. The particular types of therapy that are possible using the neuromuscular stimulation assembly 10 will be described later. Once the particular muscle and/or tissue region is identified, an electronics pod 20 (or a carrier 16 with integrated electronics pod 20) is placed on the skin overlying the region (see FIG. 6) and secured in place with pressure sensitive adhesive on the bottom of one-half of the pod/carrier. As previously stated, the adhesive region desirably contains a bacteriostatic sealant that prevents skin irritation or superficial infection, which could lead to premature removal.
As FIG. 6 shows, the electronics pod 20 (or carrier 16 with integrated electronics pod 20) is placed on the skin in an opened condition, to expose the skin region 38 between the pod (or carrier 16) sections 32 and 34.
As FIGS. 7 to 10 show, the clinician proceeds to percutaneously implant the electrodes 14 and lead 12, one by one, through the desired skin region 38. While each electrode 14 is sequentially implanted, the electrode introducer 50 applies a stimulation signal until a desired response is achieved, at which time the electrode 14 is deployed and the introducer 50 is withdrawn.
Upon implanting each electrode (see FIG. 7), the clinician routes each electrode lead 12 to a given trough 30. The clinician notes which electrode 14 is coupled to which channel.
After implanting all the electrode 14 and routing each lead 12 (see FIG. 9), the clinician closes the electronics pod 20 (or carrier 16 with integrated electronics pod 20) (see FIG. 10). In the former situation, the clinician snap-fits the carrier 16 over the electronics pod 20, as FIG. 11 shows. The adhesive region 18 on the carrier 16 secures the carrier 16 to the skin. A battery 42 is placed into the power input bay 40. The neuromuscular stimulation assembly 10 is ready for use.
Typically, as shown in FIG. 17, a container 52 holding a prescribed number of replacement batteries 42 will be provided with the neuromuscular stimulation assembly 10, forming a neuromuscular stimulation system 54. Instructions for use 56 may accompany the neuromuscular stimulation system 54. The instructions 56 prescribe use of the neuromuscular stimulation assembly 10, including the periodic removal and replacement of a battery 42 with a fresh battery 42. Thus, the instructions 56 prescribe a neuromuscular stimulation regime that includes a periodic recharging, via battery replacement, of the neuromuscular stimulation assembly 10 in the same fashion that pill-based medication regime directs periodic “recharging” of the medication by taking of a pill. In the context of the neuromuscular stimulation system 54, a battery 42 becomes the therapeutic equivalent of a pill (i.e., it is part of a user action taken to extend treatment).
As FIG. 13 shows, external desktop or handheld (desirably also battery powered) preprogrammed instruments 46 can be used to program stimulus regimes and parameters into the neuromuscular stimulation assembly 10, or to download recorded data from the neuromuscular stimulation assembly 10 for display and further processing. The instruments 46 can communicate with the neuromuscular stimulation assembly 10, e.g., by a cable connection, by radio frequency magnetic field coupling, by infrared, or by RF wireless. As before described, the power input bay 40 can additionally comprise a communications interface, that is coupled to a communications cable 58 connected to the instrument 46. The communications cable 58 provides power to the neuromuscular stimulation assembly 10 during programming, as well as communications with the circuitry 24 of the neuromuscular stimulation assembly 10. The external programming instrument 46 can also be a general purpose personal computer or personal digital device fitted with a suitable custom program and a suitable cable or interface box for connection to the communications cable 58.
The programming instruments 46 allow a clinician to customize the programmable code 26 residing in an individual neuromuscular stimulation assembly 10 according the specific needs of the user and the treatment goals of the clinician. The neuromuscular stimulation assembly 10 can, once customized, be disconnected from the programming system, allowing portable, skin-worn operation, as already described.
III. Representative Use of the Neuromuscular Stimulation Assembly/System
A. Overview
The neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54, as described, make possible the providing of short-term therapy or diagnostic testing by providing electrical connections between muscles or nerves inside the body and stimulus generators or recording instruments mounted on the surface of the skin outside the body. The programmable code 26 of the neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 can be programmed to perform a host of neuromuscular stimulation functions, representative examples of which will be described for the purpose of illustration.
B. Continuous Active Motion (CAM)
CAM using the neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 provides the stimulus necessary to improve cardiovascular endurance, muscular strength, and neurologic coordination. Through the CAM, this active-assisted exercise is a technique used to assist the active, voluntary movement of the target limb, thereby decreasing the amount of strength needed to move the joints. This technique has been proven effective in increasing the strength of individuals beginning at very low levels. Therapeutic benefits include reduced inflammation of the affected joint, improved range of motion, pain relief, and enhanced functional mobility. CAM is differentiated from continuous passive motion (CPM), which is the movement of a joint or extremity through a range of motion without voluntary movement of the limb.
C. Post Trauma Anti-Scarring Treatment
Post Surgical scarring, (e.g. posterior approaches to the spine), is the bane of most Orthopedic or Neurosurgical procedures. Scarring or adhesion, that is a fibrous band of scar tissue that binds together normally separate anatomical structures during the healing process, can be one of the single greatest reasons for patient's surgical “failure”. A terrific and well executed operation by a gifted surgeon can be wasted in a short time due to the body's tendency to scar during post surgical healing. By applying the neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 to the muscles or nerves in the specific surgical wound area, relatively small motions may prevent scarring, while the tissue is healing.
D. Temporary, Non-Surgical Diagnostic Assessment
Prior to the administering of a specific permanent implanted neuromodulation or neurostimulation system, (e.g. urinary incontinence, vagal nerve stimulation for epilepsy treatment, spinal cord stimulators for pain reduction), the neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 can be applied to provide the physician and their patient with some assurance that through the temporary stimulation of the end organ, the treatment is viable. This would allow the physician to screen patients that may not be candidates for the permanent treatment, or otherwise, may not find the effect of the treatment to worth the effort of the surgical implantation of a permanent system.
E. Neuroplasticity Therapy
Individuals with neurological deficits, such as stroke survivors or those with multiple sclerosis may lose control of certain bodily functions. The brain, may, through a process called “neuroplasticity,” recover functionally, by reorganizing the cortical maps or spinal cord-root interfaces and increasing auxiliary blood supply, which contributes to neurological recovery. By applying the neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 to affected areas of the body and providing excitation and input to the brain, a neuroplastic effect may occur, enabling the brain to re-learn and regain control of the lost function.
F. Anti-Spasm Therapy
The use of temporary neurotoxins (e.g. botox) has become widespread in treating severe muscles spasms from cerebral palsy, head injury, multiple sclerosis, and spinal cord injury to help improve walking, positioning and daily activities. Botox can also be used to treat eye conditions that cause the eye to cross or eyelid to blink continuously. It is also purported to eliminate wrinkles by limiting the ageing process. The neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 may be used as an alternative means of reducing the spasticity without having to temporarily paralyze the nerves and muscles. The neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 also may be useful in treating TMJ (temporomandibular joint) disorders, which are manifested by pain in the area of the jaw and associated muscles spasms and limitations in the ability to make the normal movements of speech, facial expression, eating, chewing, and swallowing.
G. Chronic or Temporary Pain Therapy
Localized pain in any area of the body can be treated with the neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 by applying it directly to the effected area. The neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 works by interfering with or blocking pain signals from reaching the brain.
H. Post-Surgical Reconditioning
Recovery of strength and muscle function following surgery can be promoted using the neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54. The assembly 10 and/or system 54 can be prescribed post-operatively and installed in association with the appropriate muscles regions to provide a temporary regime of muscle stimulation, alone or in conjunction with a program of active movements, to aid an individual in recovering muscle tone, function, and conditioning following surgery.
I. Thromboembolism Prophyllaxis
The neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 can provide anti-thrombosis therapy by stimulating the leg muscles which increases venous return and prevent blood clots associated with pooling of blood in the lower extremities. Routine post-operative therapy is currently the use of pneumatic compression cuffs that the patients wear on their calves while in bed. The cuffs cycle and mechanically compress the calf muscles, thereby stimulating venous flow. Patients hate this, but every surgical bed in the hospital now has this unit attached to it. This same effect could be duplicated by installing a neuromuscular stimulation assembly 10. Prophyllaxis is most effective if begun during surgery, as many, if not most clots, form during surgery. Thus, it is desirable to install a neuromuscular stimulation assembly 10 and begin use of the neuromuscular stimulation system 54 at the beginning of an operation.
J. Treatment of Osteoporosis
Cyclic muscle contraction loads bone sufficiently to prevent (and possibly) reverse osteoporosis. The effectiveness of such treatment is known to be frequency dependent. The neuromuscular stimulation assembly 10 and/or neuromuscular stimulation system 54 can be programmed to stimulate muscles at the appropriate frequency to prevent/reverse osteoporosis.
Various features of the invention are set forth in the following claims.

Claims

1. A percutaneous electrode assembly comprising

a flexible body including an electrically conductive region, a tissue penetrating region for implantation of the electrically conductive region in a targeted tissue region, and a percutaneous lead electrically coupled to the electrically conductive region,

an anchoring element on the flexible body to resist movement of the electrically conductive region within tissue, and

an introducer having an interior lumen sized and configured to receive the flexible body and shield the anchoring element from contact with tissue while the electrically conductive region is placed to a desired position within tissue, the introducer also being sized and configured to accommodate advancement of the anchoring element beyond the interior lumen for contact with tissue to resist movement of the electrically conductive region placed in the desired position.

2. An assembly according to claim 1

wherein the flexible body is sized to have a diameter not greater than about 0.5 mm.

3. An assembly according to claim 1

wherein the anchoring element comprises a barb.

4. An assembly according to claim 1

wherein the introducer includes an electrically isolated area that correspond to the electrically conductive region of the flexible body.

5. An assembly according to claim 4

wherein the electrically isolated area is electrically coupled to a connector on the introducer to allow the electrically isolated area to be coupled to a stimulating circuit.

6. A method of implanting a percutaneous electrode comprising the steps of

providing a percutaneous electrode with an anchoring element to resist movement of the percutaneous electrode within tissue,

inserting the percutaneous electrode within an introducer that shields the anchoring element from contact with tissue,

implanting the percutaneous electrode while inserted within the introducer, to place the percutaneous electrode in a desired location within tissue, and

withdrawing the introducer to place the anchoring element in contact with tissue, thereby resisting movement of the percutaneous electrode from the desired position.

7. A method according to claim 6

further including, during the implanting step, a step of coupling the percutaneous electrode to a stimulating circuit to provoke a tissue stimulation response to place the percutaneous electrode in the desired location.

8. A method according to claim 6

9. A method according to claim 8

10. A method according to claim 9

further including, during the implanting step, a step of coupling the introducer to a stimulating circuit to provoke a tissue stimulation response to place the percutaneous electrode in the desired location.

11. A percutaneous electrode assembly comprising

a flexible body including one or more electrically conductive regions, a tissue penetrating region for implantation of the electrically conductive regions in a targeted tissue region, and a percutaneous lead electrically coupled to the electrically conductive regions, the lead including a conductor for each electrically conductive region,

a flexible introducer having an interior lumen sized and configured to receive the flexible body and shield the anchoring element from contact with tissue while the electrically conductive region is placed to a desired position within tissue, the flexible introducer also being sized and configured to accommodate advancement of the anchoring element beyond the interior lumen for contact with tissue to resist movement of the electrically conductive region placed in the desired position.

12. An assembly according to claim 11

wherein the flexible introducer is sized and configured to accommodate advancement of the flexible body and anchoring element beyond the interior lumen while the flexible introducer is bent.