Patent Application
20050021118
The following disclosure is related to apparatuses and systems for applying neural stimulation to a patient, for example, at a surface site on the patient's cortex.
A wide variety of mental and physical processes are controlled or influenced by neural activity in particular regions of the brain. The neural functions in some areas of the brain (e.g., the sensory or motor cortices) are organized according to physical or cognitive functions. Several other areas of the brain also appear to have distinct functions in most individuals. In the majority of people, for example, the occipital lobes relate to vision, the left interior frontal lobes relate to language, and the cerebral cortex appears to be involved with conscious awareness, memory, and intellect.
Many problems or abnormalities can be caused by damage, disease, and/or disorders of the brain. Effectively treating such abnormalities may be very difficult. For example, a stroke is a common condition that damages the brain. Strokes are generally caused by emboli (i.e., obstruction of a blood vessel), hemorrhages (i.e., rupture of a blood vessel), or thrombi (i.e., clotting) in the vascular system of a specific region of the brain. Such events generally result in a loss or impairment of neural function (e.g., neural functions related to facial muscles, limbs, speech, etc.). Stroke patients are typically treated using various forms of physical therapy that rehabilitate the loss of function of a limb or another affected body part. Stroke patients may also be treated using physical therapy plus an adjunctive therapy such as amphetamine treatment. For most patients, however, such treatments are minimally effective and little can be done to improve the function of an affected body part beyond the recovery that occurs naturally without intervention.
Problems or abnormalities in the brain are often related to electrical and/or chemical activity in the brain. Neural activity is governed by electrical impulses or “action potentials” generated in neurons and propagated along synaptically connected neurons. When a neuron is in a quiescent state, it is polarized negatively and exhibits a resting membrane potential typically between −70 and −60 mV. Through chemical connections known as synapses, any given neuron receives excitatory and inhibitory input signals or stimuli from other neurons. A neuron integrates the excitatory and inhibitory input signals it receives and generates or fires a series of action potentials when the integration exceeds a threshold potential. A neural firing threshold, for example, may be approximately −55 mV.
It follows that neural activity in the brain can be influenced by electrical energy supplied from an external source such as a waveform generator. Various neural functions can be promoted or disrupted by applying an electrical current to the cortex or other region of the brain. As a result, researchers have attempted to treat physical damage, disease, and disorders in the brain using electrical or magnetic stimulation signals to control or affect brain functions.
Transcranial electrical stimulation (TES) is one such approach that involves placing an electrode on the exterior of the scalp and delivering an electrical current to the brain through the scalp and skull. Another treatment approach, transcranial magnetic stimulation (TMS), involves producing a magnetic field adjacent to the exterior of the scalp over an area of the cortex. Yet another treatment approach involves direct electrical stimulation of neural tissue using implanted electrodes.
The neural stimulation signals used by these approaches may comprise a series of electrical or magnetic pulses that can affect neurons within a target neural population. Stimulation signals may be defined or described in accordance with stimulation signal parameters that include pulse amplitude, pulse frequency, duty cycle, stimulation signal duration, and/or other parameters. Electrical or magnetic stimulation signals applied to a population of neurons can depolarize neurons within the population toward their threshold potentials. Depending upon stimulation signal parameters, this depolarization can cause neurons to generate or fire action potentials.
Neural stimulation that elicits or induces action potentials in a functionally significant proportion of the neural population to which the stimulation is applied is referred to as supra-threshold stimulation; neural stimulation that fails to elicit action potentials in a functionally significant proportion of the neural population is defined as sub-threshold stimulation. In general, supra-threshold stimulation of a neural population triggers or activates one or more functions associated with the neural population, but sub-threshold stimulation by itself does not trigger or activate such functions. Supra-threshold neural stimulation can induce various types of measurable or monitorable responses in a patient. For example, supra-threshold stimulation applied to a patient's motor cortex can induce muscle fiber contractions in an associated part of the body to produce an intended type of therapeutic, rehabilitative, or restorative result.
One shortcoming of the prior art electrode assembly 100 is that the substrate 102 has a thickness 101 of about 2.5 mm. Although this thickness may be acceptable for certain spinal cord applications, it can present problems in intracranial applications where space between the skull and cortex is limited. For example, one such problem is that implantation of the electrode assembly 100 in the narrow confines between the skull and cortex can cause the electrode assembly 100 to apply localized pressure to the cortex of the patient.
Another shortcoming of the electrode assembly 100 is associated with the intermediate coupling between the connector 112 and the receptacle 114. This coupling is relatively large and, accordingly, it may be difficult to push through a tunnel extending, for example, from a subclavicular region, along the back of the neck, and around the skull of a patient. Not only is this coupling relatively large, but it is also relatively fragile and prone to damage during use. Such damage can include breakage of the connector 112 due to over-tightening of the corresponding set-screws 115. In addition, use of an intermediate coupling can increase the risk of fatigue failure of the lead as it is bent around the relatively sharp radius of the receptacle 114.
A further shortcoming associated with the prior art electrode assembly 100 is the relatively time-intensive manufacturing process required to break out each individually insulated lead 108 from the cable 106 and then crimp each individual lead 108 to its corresponding electrode 104. In addition, these crimps may be prone to breakage from flexing of the substrate 102 during implantation, which renders the electrode assembly 100 at least partially inoperative. If inoperative, the electrode assembly 100 may have to be removed from the patient, and a second invasive procedure may be necessary to implant another fully operative electrode assembly.
In spinal cord therapy, it is often desirable to focus electrical stimulation within 1-2 mm of a target location to enhance the efficacy of the procedure. It is for this reason that the electrode assembly 100 includes a quadripolar array of electrodes 104 providing multiple stimulation combinations within a relatively short distance. The quadripolar array allows the relative electrical potentials between any two electrodes to be tuned to focus the electrical stimulation in the narrow space between the two electrodes. While this configuration may be useful in certain spinal cord applications, it may be less useful in those applications where broader coverage is desired. Such applications may include, for example, certain applications where broader stimulation of the cortical site is desired.
The present disclosure describes apparatuses and systems for applying electrical stimulation to cortical and other sites on a patient, and associated methods of manufacturing such apparatuses. Stimulation systems and methods described herein may be used to treat a variety of neurological conditions. Depending on the nature of a particular condition, neural stimulation applied or delivered in accordance with various embodiments of such systems and/or methods may facilitate or effectuate reorganization of interconnections or synapses between neurons to (a) provide at least some degree of recovery of a lost function; and/or (b) develop one or more compensatory mechanisms to at least partially overcome a functional deficit. Such reorganization of neural interconnections may be achieved, at least in part, by a change in the strength of synaptic connections through a process that corresponds to a mechanism commonly known as Long-Term Potentiation (LTP). Electrical stimulation applied to one or more target neural populations either alone or in conjunction with behavioral activities and/or adjunctive or synergistic therapies may facilitate or effectuate neural plasticity and the reorganization of synaptic interconnections between neurons.
One embodiment of a system for applying electrical stimulation to a cortical stimulation site in accordance with the invention includes an implantable electrode assembly connected to a stimulus unit. The stimulus unit can be an implantable pulse generator (IPG) having at least a first terminal that can be biased at a first electrical potential and a second terminal that can be biased at a second electrical potential. The implantable electrode assembly can include an array of electrodes carried by a flexible support member configured to be placed at the stimulation site. A first conductor or lead can connect a first plurality of the electrodes to the first terminal of the IPG, and a second conductor or lead can connect a second plurality of the electrodes to the second terminal of the IPG. In operation, the IPG can bias the first plurality of electrodes at the first potential and the second plurality of electrodes at the second potential to generate an electric field at least proximate to the stimulation site for promoting neuroplasticity. As used herein, the term “stimulation site” refers to a location where target neurons for a particular therapy are located. For example, in certain embodiments, such locations may be proximate to the cortex, either on the dura mater or beneath the dura mater.
Certain specific details are set forth in the following description and in
In the figures, identical reference numbers identify identical or at least generally similar elements. To facilitate the discussion of any particular element, the most significant digit or digits of any reference number refer to the figure in which that element is first introduced. For example, element 210 is first introduced and discussed with reference to
Although the electrode assembly 200 of the illustrated embodiment includes a 2×3 electrode array (i.e., 2 rows of 3 electrodes each), in other embodiments, electrode assemblies in accordance with the present invention can include more or fewer electrodes in other types of symmetrical and asymmetrical arrays. For example, in one other embodiment, such an electrode assembly can include a 1×2 electrode array. In another embodiment, such an electrode assembly can include a 2×5 electrode array. In a further embodiment, such an electrode assembly can include a single electrode for isopolar stimulation. Furthermore, although the electrodes 220 appear to be evenly spaced along respective sides of the electrode assembly 200, in other embodiments, the electrodes 220 can have other spacing. For example, in one other embodiment, the space between the first electrode 220a and the second electrode 220b can be different than the space between the second electrode 220b and the third electrode 220c. Similarly, in this embodiment, the space between the fourth electrode 220d and the fifth electrode 220e can be different than the space between the fifth electrode 220e and the sixth electrode 220f. Several other electrode configurations are shown and described in U.S. application Ser. No. 10/112,301, filed Mar. 28, 2002, which is herein incorporated in its entirety by reference. Accordingly, aspects of the electrode assemblies disclosed herein in accordance with the present invention are not limited to the embodiments illustrated, but instead they can be applied to other electrode assemblies having other configurations.
In another aspect of this embodiment, the electrode assembly 200 can be shaped and sized to facilitate intracranial use without installation difficulties or patient discomfort. For example, in one embodiment, the support member 210 can have a relatively thin thickness T of about 1.25 mm. This thickness is less likely to apply localized pressure to the cortex of the patient than thicker devices, such as the prior art electrode assembly 100 of
In yet another aspect of this embodiment, the electrode assembly 200 can include one or more coupling apertures 214 extending through the periphery of the support member 210. As explained in greater detail below, in one embodiment, the coupling apertures 214 can facilitate temporary attachment of the electrode assembly 200 to dura mater at, or at least proximate to, a stimulation site. The electrode assembly 200 can also include a protective sleeve 232 disposed over a portion of the cable 230. In one embodiment, the sleeve 232 can be manufactured from a silicone material having a relatively high durometer. In other embodiments, other suitable materials can be used to protect the cable 230 from abrasion and provide strain relief for the support member 210. As further explained below, in one embodiment, the sleeve 232 can protect the cable 230 from abrasion resulting from contact with the edge of an access hole formed in the patient's skull.
In addition to the grooves 321, in one embodiment, each of the electrodes 220 can also include a plurality of adhesive apertures 327 extending axially through the shoulder portions of the electrodes 220. As explained below with reference to
The electrodes 220 may be comprised of various electrically conductive materials. For example, in one embodiment, the electrodes 220 can include platinum and iridium in about a 9-to-1 ratio, respectively. In other embodiments, the electrodes 220 can include platinum and iridium in other ratios. In a further embodiment, the electrodes 220 can include only platinum. In yet other embodiments, the electrodes 220 can include other conductive materials suitable for patient implantation in medical applications such as stainless steel, nickel, titanium and/or gold. In still further embodiments, the electrodes 220 can include material coatings to increase the effective surface area of the electrodes 220 and/or decrease the electrical impedance at the tissue interface. Such coatings can include iridium, titanium oxide films, and/or metal blacks.
The electrodes 220 can be manufactured using a number of different methods in various embodiments. For example, in one embodiment, the electrodes 220 can be machined from stock. In another embodiment, the electrodes 220 can be cast. In a further embodiment, the electrodes 220 can be forged. In yet another embodiment, the electrodes 220 can be stamped from a thin sheet of material to provide the necessary cross-sectional shape. In still further embodiments, it is expected that still other methods can be used to manufacture the electrodes 220.
Although the electrodes 220 of the illustrated embodiment are at least generally round, in other embodiments, the electrodes 220 can have other geometrical shapes. For example, in one other embodiment, the electrodes 220 can be at least generally square or have other rectangular shapes. In further embodiments, the electrodes 220 can have other multi-sided shapes, such as triangles, octagons or hexagons. In yet other embodiments, the electrodes can have oval or elliptical shapes. In still further embodiments, it is expected that electrodes can have still other shapes, such as irregular shapes, depending on the particular application.
In another aspect of this embodiment, the grooves 321 in the electrodes 220 are configured to receive conductors or lead lines 340 (illustrated as a first lead line 340a and a second lead line 340b). In the illustrated embodiment, for example, the first grooves 321a in the first plurality of electrodes 221 receive a distal portion of the first lead line 340a, and the first grooves 321a in the second plurality of electrodes 222 similarly receive a distal portion of the second lead line 340b. Recessing the lead lines 340 in the grooves 321 can favorably reduce the overall thickness of the electrode assembly 200 as compared to, for example, extending the lead lines 340 over the tops of the electrodes 220 for attachment by crimping or some other method. As described in greater detail below, the lead lines 340 can be connected to a stimulus unit to produce a desired electric field between the first plurality of electrodes 221 and the second plurality of electrodes 222.
The lead lines 340 may be comprised of various electrically conductive materials. In one embodiment, for example, the lead lines 340 can include MP35N quadrifiler coil wire having a 0.254 mm outside diameter. Such coil wire may be provided by Lake Region Manufacturing, VNS-001-01K. In other embodiments, the lead lines 340 can include other types of electrically conductive wire. For example, in one other embodiment, the lead lines 340 can include single-strand MP35N wire. In yet another embodiment, the lead lines 340 can include multi-strand MP35N wire, such as 21-strand MP35N wire. Multi-strand wire may have certain advantages over other types of wire in selected embodiments. For example, multi-strand wire may cost less than coil wire, may have a higher tensile strength, and may have a lower impedance. In addition to the forgoing materials, the lead lines 340 can also include drawn filled tubing (DFT) materials, such as those provided by Fort Wayne Metals of 9609 Indianapolis Road, Fort Wayne, Ind. 46809. Such DFT wire materials can include various outer tube/core combinations. For example, the outer tube materials can include MP35N, 316LVM, Nitinol, Conichrome, and titanium alloys, among others; and the core materials can include gold, silver, platinum and tungsten, among others.
In a further aspect of this embodiment, the support member 210 includes a top or first portion 311a and a complimentary bottom or second portion 311b. The second portion 311b can include a plurality of electrode ports 315a-f configured to receive the electrodes 220a-f, respectively. In the illustrated embodiment, each electrode port 315 includes a contact aperture 316 and an annular recess 318 formed concentrically around the contact aperture 316. Each of the contact apertures 316 is configured to receive the base portion 324 of a corresponding electrode 220. Similarly, each of the annular recesses 318 is configured to receive at least part of the shoulder portion 323 of the corresponding electrode 220. In this manner, at least a portion of the contact surface 325 of each electrode 220 is exposed through the contact aperture 316 when the electrode 220 is fully installed in the electrode port 315. This positioning allows each electrode 220 to contact a tissue surface when the support member 210 is placed at a stimulation site.
In yet another aspect of this embodiment, the second portion 311b of the support member 210 can include a plurality of preformed grooves 313 (shown as a first groove 313a, second groove 313b, a third groove 313c, and a fourth groove 313d). The grooves 313 can extend from one or more of the electrode ports 315 to at least proximate a collar 317. The grooves 313 are configured to receive exposed portions of the lead lines 340 extending between the electrodes 220 and the cable 230. For example, in the illustrated embodiment, the first groove 313a receives an exposed portion of the first lead line 340a, and the second groove 313b receives an exposed portion of the second lead line 340b. The curved paths formed by the grooves 313 between the electrodes 220 and the cable 230 are shaped and sized to reduce strain between the lead lines 340 and the electrodes 220 when the support member 210 is flexed, stretched, or otherwise manipulated during use. This feature can reduce the likelihood of breaking a connection between one of the lead lines 340 and one of the electrodes 220 during implantation of the electrode assembly 200. In one embodiment, the grooves 313 can have a generally U-shaped cross-section. In another embodiment, the grooves 313 can be undercut to facilitate retention of the lead lines 340 in the second portion 311b.
In a further aspect of this embodiment, the first and second portions 311 of the support member 210 include a number of features to reduce stress and strain from use. For example, in one embodiment, the second portion 311b can include generous radiuses 365 extending between the collar 317 and the body of the second portion 311b. The radiuses 365 can reduce strain on the support member 200 from flexing of the cable 230 during use. In another embodiment, the first portion 311a can include an angled surface 367 that bonds to a corresponding surface of the collar 317. The angled joint between the two respective surfaces may provide certain strain relief advantages over a joint that is orientated perpendicular to the cable 230. In addition to the forgoing features, the first portion 311a can also include generous fillet radii between a raised portion 369 that receives the cable 230 and the body of the first portion 311a. In other embodiments, the first and second portions 311a, b can have other strain relief features in addition to those described here, or alternatively, one or more of the features described here may be omitted.
The first and second portions 311 of the support member 210 may be comprised of various flexible and/or elastomeric materials. In one embodiment, for example, both the first portion 311a and the second portion 311b can be manufactured from NUSIL MED-4870 silicone elastomer. In other embodiments, the first and second portions 311 can be manufactured from other flexible materials known to those in the art as being suitable for intracranial implantation for medical applications.
In a further aspect of this embodiment, portions of the lead lines 340 extending away from the support member 210 can be individually housed within inner tubes 342 to insulate the lead lines 340 from each other. The inner tubes 342 can in turn be housed together within an outer tube 344 to form the cable 230 extending between the support member 210 and the connector 233 (
In another aspect of this embodiment, each of the electrodes 220 is installed into a corresponding one of the electrode ports 315. A suitable adhesive, such as NUSIL MED-1511 silicone adhesive, can be applied to portions of the electrodes 220 and/or portions of the second portion 311b (such as the annular recesses 318) during installation to seal and secure the electrodes 220 to the second portion 311b. In this respect, the annular recesses 318 can provide favorable “pocket” to contain the adhesive and position the corresponding electrodes 220. In one embodiment, the adhesive apertures 327 can allow the adhesive to flow through each electrode 220 and extend between the first and second portions 311a, b of the support member 210. This feature can facilitate bonding between the first and second portions 311a, b. Further, this feature can help to secure the electrodes 220 with respect to the support member 210 and prevent an electrode 220 from becoming dislodged by flexing of the support member 210 during implantation of the electrode assembly 200.
In a further aspect of this embodiment, the first lead line 340a is installed into the first groove 313a of the support member second portion 311b, and the second lead line 340b is similarly installed into the second groove 313b. In addition, the cable 230 is inserted through the collar 317 to position a cable end 332 at least approximately between the third electrode 220c and the sixth electrode 220f. By positioning the cable end 332 at this location, bending or flexing of the cable 230 is not likely to cause the support member 210 to fold in a sharp bend along a line 319 proximate to the cable end 332. Instead, the support member 210 is likely to assume a more gentle bend over the region forward of the electrodes 220c, f. Avoiding sharp bending of the support member 210 in this manner may help to limit strains between, for example, the lead lines 340 and the electrodes 220. Such strains can lead to breakage of lead line/electrode connections and possibly result in malfunction of the electrode assembly. Further, sharp bending of the support member 210 may also tend to dislodge an electrode 220 from the support member 210. After the electrodes 220 and the lead lines 340 are installed on the second portion 311b as illustrated in
One feature of embodiments of the invention illustrated in
Additional features of embodiments of the invention can be seen with reference to
The lead lines 340, 440 of this embodiment can be attached to the electrodes 220 in a number of different ways. For example, referring to the first plurality of electrodes 221, in one embodiment, the third lead line 440a can be attached to the second electrode 220b with welds 441a, b positioned on opposite sides of the first lead line 340a. The first lead line 340a can be attached to the second electrode 220b with a similar weld 441c. The third lead line 440a can be attached to the first and, third electrodes 220a, c with welds 341 as shown above in
Referring next to
In yet another aspect of this embodiment, the flex portions 564 can be configured to allow for relative motion between the electrodes 520 while maintaining the connection between the electrodes 520. In the illustrated embodiment, for example, the flex portions 564 include one or more convolutions. In other embodiments, the flex portions 564 can have other configurations to accommodate relative motion between the electrodes 520.
The preformed wires 560 may be comprised of various conductive materials. For example, in one embodiment, the preformed wires 560 can include MP35N wire having a diameter of about 0.127 mm. In another embodiment, the preformed wires 560 can include quadrifiler coil having a diameter of 0.254 mm. In a further embodiment, the preformed wires 560 can include other conductive metals such as various steels, nickel, platinum, titanium, and/or gold.
Although the preformed wires 560 of the illustrated embodiment are resilient wires, in other embodiments, nonpreformed and/or nonresilient wires can be used to interconnect the electrodes 520 by attaching to the sides of the electrodes 520. For example, in one other embodiment, the electrodes 520 can be interconnected by a single strand of nonresilient wire that is welded into a small portion of each groove 522 without wrapping very far around the electrode 520. In another embodiment, the electrodes 520 can be interconnected by a coiled wire that is similarly welded into the grooves 522. In all of these embodiments, the annular grooves 522 should be appropriately sized to accommodate the particular type of wire used. In yet other embodiments, the grooves 522 can be omitted and the interconnecting wires can be welded directly to the sides of the electrodes 520. It will be appreciated that one benefit of these embodiments is that the interconnecting wires (e.g., the preformed wires 560) can interconnect the electrodes 520 without extending over the tops of the electrodes 520, thereby keeping the thickness of the support member to a minimum.
In another aspect of this embodiment, the first and second electrodes 620a, b can be spaced apart by a distance 662. In one embodiment, the distance 662 can be greater than about 31 mm, such as about 35 mm, to provide or induce a desired therapeutic effect that may be enhanced by such spacing. In other embodiments, the distance 662 can be less than about 31 mm and/or determined in accordance with certain anatomical considerations and/or the nature or extent of the patient's disorder or condition.
In a further aspect of this embodiment, the second portion 611b includes a collar 617 that is at least partially offset toward one side of the second portion 611b. One advantage of this feature is that it allows each of the first and second lead lines 640a, b to have an at least generally direct path to the corresponding electrode 620a, b, respectively. Here, an “at least generally direct path,” means that the lead line 640a, for example, does not have to cross over, or make a substantial detour around, the second electrode 620b to get to the first electrode 620a. In addition, the second portion 611b can include a generous radius 665 between the collar 617 and the body of the second portion 611b. The radius 665 can favorably reduce strain caused by flexing of the collar 617. In other embodiments, however, the collar 617 may be generally centered relative to the second portion 611b, and/or the radius 665 my be reduced or omitted.
In another aspect of this embodiment, the passages 731 may be filled with adhesive for a distance F proximate to each end of the multi-lumen tube 745. This adhesive can prevent or reduce relative motion between the lead lines 340 and the multi-lumen tube 745 as the multi-lumen tube 745 is flexed or stretched during use. Reducing this relative motion may reduce internal abrasion of the multi-lumen tube 745 and/or strain of the lead lines 340 that could result in malfunction of the electrode assembly 700.
One advantage of the cable 730 over the cable 230 described above (
In another aspect of this embodiment, the stimulus unit 850 generates and outputs stimulus signals, such as electrical and/or magnetic stimuli. In the illustrated embodiment, the stimulus unit 850 is generally an implantable pulse generator that is implanted into the patient P in a thoracic, abdominal, or subclavicular location. In other embodiments, the stimulus unit 850 can be an IPG implanted in the skull or just under the scalp of the patient P. For example, in one other embodiment, the stimulus unit 850 can be implanted above the neck-line or in the skull of the patient P as set forth in U.S. patent application Ser. No. 09/802,808.
In a further aspect of this embodiment, the stimulus unit 850 includes a controller 830 and a pulse system 840. The controller 830 can include a processor, a memory, and computer-readable instructions stored on a programmable computer-readable medium. The controller 830 can be implemented as a computer or a microcontroller. The programmable medium can include software loaded into the memory and/or hardware that performs, directs, and/or facilitates neural stimulation procedures.
In yet another aspect of this embodiment, the pulse system 840 can generate energy pulses that are outputted to a first terminal 842a and a second terminal 842b. The first terminal 842a can be biased at a first potential and the second terminal can be biased at a second potential at any given time. In one embodiment, the first potential can have a first polarity and the second potential can have a second polarity or be neutral. That is, the first potential can be either anodal or cathodal, and the second potential can be opposite the first polarity or neutral. In another embodiment, the first potential and the second potential can have the same polarity.
In a further aspect of this embodiment, the electrical stimulation system does not include an intermediate connector between the electrode assembly 200 and the stimulus unit 850. One advantage of this feature is that it provides a complete end-to-end system without the bulk of an intermediate connector and the associated risk of connector failure. In other embodiments, however, one or more connectors can be included between the electrode assembly 200 and the stimulus unit 850. In one such other embodiment, the first and second terminals 842a, b can be included in a single connector connecting the electrode assembly 200 to the pulse system 840.
As described in detail above with reference to
In another embodiment, all of the electrodes 220 can be biased at the same potential in an isopolar arrangement. In this embodiment, the electrode assembly 200 can generate an electrical pulse between the electrodes 220 and a separate pole (not shown in
In another aspect of this embodiment, the support member 210 can be stitched or otherwise attached to the dura mater 906 at the stimulation site by looping one or more couplings 980 through the dura mater 906 and through one or more of the coupling apertures 314 in the support member 210. In one embodiment, the coupling 980 can include a simple suture. In other embodiments, other forms of attachment can be used to at least temporarily hold the support member 210 in position at the stimulation site. For example, in one other embodiment, the coupling apertures 314 can be omitted and a needle can be used to extend sutures or other couplings through the support member material. A bio-compatible adhesive can also be used in conjunction with, or as an alternative to, the sutures. In yet another embodiment, a positive form of attachment between the support member 210 and the dura mater 906 can be omitted. After implantation of the electrode assembly 200 at the stimulation site, the skull portion 903 is replaced and sutured and/or otherwise attached to the skull 901 to at least partially cover the hole 904.
In a further aspect of this embodiment, the cable 230 can include a preformed convoluted portion 934 proximate to the junction between the cable 230 and the support member 210. The convoluted portion 934 can act as a strain relief that prevents the support member 210 from exerting undue pressure on the stimulation site as a result of excessive cord movement. For example, if a practitioner momentarily pushes on the cable 230 during implantation of the electrode assembly 200, or if the cable 230 shifts for another reason after implantation, the convoluted portion 934 may act to dampen this motion and avoid transmitting it to the support member 210. Otherwise, such motion of the support member 210 may apply undesirable pressure to the stimulation site, resulting in discomfort to the patient. In yet another aspect of this embodiment, the sleeve 232 may protect the cable 230 from abrasion on the edge of the notch 905.
In another aspect of this embodiment, the support member 1210 includes a first end 1217a spaced apart from a second end 1217b defining a width W therebetween. The support member 1210 can further include a length L that is transverse to the width W and less than the width W. In a further aspect of this embodiment, the cable 1230 can be attached to the second portion 1211b of the support member 1210 at least generally between the first end 1217a and the second end 1217b. This support member configuration may provide a favorable orientation of the electrodes 1220 at certain stimulation sites to provide or induce a desired therapeutic effect.
Although the support member 1210 of the illustrated embodiment is at least generally rectangular, in other embodiments, the support member 1210 can have other shapes wherein the width W exceeds the length L and the cable 1230 is attached to the support member between the first and second ends. For example, in one such embodiment, the support member can be at least generally oval in shape.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number, respectively. Additionally, the words “herein,” “above” and “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application.
The description of embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, other embodiments are possible within the scope of the invention, as those skilled in the relevant art will recognize. For example, while certain embodiments have been described in the context of intracranial therapy, it is expected that other embodiments may be useful in other applications, such as spinal cord therapy. Further, aspects of the invention can be modified, if necessary, to employ the systems, functions and concepts of the patent applications cited above that are incorporated herein by reference. These and other changes can be made to the invention in light of the detailed description.
From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.
This application claims the benefit of copending U.S. Provisional Patent Application No. 60/482,937, filed Jun. 26, 2003, and is a continuation-in-part of U.S. patent application Ser. No. 10/260,227, filed Sep. 27, 2002, which claims the benefit of U.S. Provisional Patent Application No. 60/325,978, filed Sep. 28, 2001, and which is a continuation-in-part of U.S. patent application Ser. No. 09/802,808, filed Mar. 8, 2001, which claims the benefit of U.S. Provisional Patent Application No. 60/217,981, filed Jul. 31, 2000. U.S. patent application Ser. Nos. 10/260,227, 09/802,808, 10/260,720, and 10/112,301; and U.S. Provisional Patent Application Nos. 60/482,937, 60/325,978, and 60/217,981; are incorporated into the present disclosure in their entireties by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60482937 | Jun 2003 | US | |
| 60325978 | Sep 2001 | US | |
| 60217981 | Jul 2000 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10260227 | Sep 2002 | US |
| Child | 10877830 | Jun 2004 | US |
| Parent | 09802808 | Mar 2001 | US |
| Child | 10877830 | Jun 2004 | US |
