Systems and methods for making and using paddle leads with adjustable spacing between adjacent electrodes

A paddle lead assembly for providing electrical stimulation of patient tissue includes a paddle body having a proximal end, a distal end, and a longitudinal axis. A plurality of spaced-apart electrodes are disposed on the paddle body. The plurality of spaced-apart electrodes include a first electrode and a second electrode. At least one adjustable region is configured and arranged to adjust a center-to-center distance between the first electrode and the second electrode. At least one lead body is coupled to the paddle body. A plurality of terminals are disposed on the at least one lead body. A plurality of conductive wires couple each of the electrodes to at least one of the plurality of terminals.

FIELD

The present invention is directed to the area of implantable electrical stimulation systems and methods of making and using the systems. The present invention is also directed to implantable electrical stimulation paddle leads that include adjustably-spaced electrodes, as well as methods of making and using the electrodes, paddle leads, and electrical stimulation systems.

BACKGROUND

Implantable electrical stimulation systems have proven therapeutic in a variety of diseases and disorders. For example, spinal cord stimulation systems have been used as a therapeutic modality for the treatment of chronic pain syndromes. Peripheral nerve stimulation has been used to treat chronic pain syndrome and incontinence, with a number of other applications under investigation. Functional electrical stimulation systems have been applied to restore some functionality to paralyzed extremities in spinal cord injury patients.

Stimulators have been developed to provide therapy for a variety of treatments. A stimulator can include a control module (with a pulse generator), one or more leads, and an array of stimulator electrodes on each lead. The stimulator electrodes are in contact with or near the nerves, muscles, or other tissue to be stimulated. The pulse generator in the control module generates electrical pulses that are delivered by the electrodes to body tissue.

BRIEF SUMMARY

In one embodiment, a paddle lead assembly for providing electrical stimulation of patient tissue includes a paddle body having a proximal end, a distal end, and a longitudinal axis. A plurality of spaced-apart electrodes are disposed on the paddle body. The plurality of spaced-apart electrodes include a first electrode and a second electrode. At least one adjustable region is configured and arranged to adjust a center-to-center distance between the first electrode and the second electrode. At least one lead body is coupled to the paddle body. A plurality of terminals are disposed on the at least one lead body. A plurality of conductive wires couple each of the electrodes to at least one of the plurality of terminals.

In another embodiment, a paddle lead assembly for providing electrical stimulation of patient tissue includes a paddle body having a proximal end, a distal end, and a longitudinal axis. A plurality of spaced-apart electrodes are disposed on the paddle body. At least one elongated member is disposed on the paddle body. The at least one elongated member has a first end and a second end opposite to the first end. A first electrode of the plurality of electrodes is coupled to the first end of the at least one elongated member and a second electrode of the plurality of electrodes is coupled to the second end of the at least one elongated member. The at least one elongated member is formed from at least one shape memory material and is configured and arranged to bend or straighten upon activation by exposure to at least one of heat or current. The bending or straightening of the at least one elongated member causes an adjustment in center-to-center spacing between the first electrode and the second electrode along a first axis. A plurality of lead bodies are coupled to the paddle body. At least one terminal is disposed on each of the plurality of lead bodies. A plurality of conductive wires couple each of the electrodes to at least one of the plurality of terminals.

DETAILED DESCRIPTION

The present invention is directed to the area of implantable electrical stimulation systems and methods of making and using the systems. The present invention is also directed to implantable electrical stimulation paddle leads that include adjustably-spaced electrodes, as well as methods of making and using the electrodes, paddle leads, and electrical stimulation systems.

Suitable implantable electrical stimulation systems include, but are not limited to, an electrode lead (“lead”) with one or more electrodes disposed on a distal end of the lead and one or more terminals disposed on one or more proximal ends of the lead. Leads include, for example, percutaneous leads, paddle leads, and cuff leads. Examples of electrical stimulation systems with leads are found in, for example, U.S. Pat. Nos. 6,181,969; 6,516,227; 6,609,029; 6,609,032; and 6,741,892; 7,244,150; 7,672,734; 7,761,165; 7,949,395; 7,974,706; and U.S. Patent Applications Publication Nos. 2005/0165465; 2007/0150036; 2007/0219595; and 2008/0071320, all of which are incorporated by reference.

FIG. 1illustrates schematically one embodiment of an electrical stimulation system100. The electrical stimulation system includes a control module (e.g., a stimulator or pulse generator)102, a paddle body104, and at least one lead body106coupling the control module102to the paddle body104. The paddle body104and the one or more lead bodies106form a lead. The paddle body104typically includes an array of electrodes134. The control module102typically includes an electronic subassembly110and an optional power source120disposed in a sealed housing114. The control module102typically includes a connector144,201(FIGS. 2A and 2B, see also222and250ofFIG. 2C) into which the proximal end of the one or more lead bodies106can be plugged to make an electrical connection via conductive contacts on the control module102and terminals (e.g.,210inFIGS. 2A and 2Band236ofFIG. 2C) on each of the one or more lead bodies106. In addition, one or more lead extensions212(seeFIG. 2C) can be disposed between the one or more lead bodies106and the control module102to extend the distance between the one or more lead bodies106and the control module102.

The electrical stimulation system or components of the electrical stimulation system, including one or more of the lead bodies106, the paddle body104, and the control module102, are typically implanted into the body of a patient. The electrical stimulation system can be used for a variety of applications including, but not limited to, spinal cord stimulation, brain stimulation, neural stimulation, muscle stimulation, and the like.

The electrodes134can be formed using any conductive, biocompatible material. Examples of suitable materials include metals, alloys, conductive polymers, conductive carbon, and the like, as well as combinations thereof. The number of electrodes134in the array of electrodes134may vary. For example, there can be two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, or more electrodes134. As will be recognized, other numbers of electrodes134may also be used.

The electrodes of the paddle body104or one or more lead bodies106are typically disposed in, or separated by, a non-conductive, biocompatible material including, for example, silicone, polyurethane, and the like or combinations thereof. The paddle body104and one or more lead bodies106may be formed in the desired shape by any process including, for example, molding (including injection molding), casting, and the like. Electrodes and connecting wires can be disposed onto or within a paddle body either prior to or subsequent to a molding or casting process. The non-conductive material typically extends from the distal end of the lead to the proximal end of each of the one or more lead bodies106. The non-conductive, biocompatible material of the paddle body104and the one or more lead bodies106may be the same or different. The paddle body104and the one or more lead bodies106may be a unitary structure or can be formed as two separate structures that are permanently or detachably coupled together.

Terminals (e.g.,210inFIG. 2A and 236ofFIG. 2C) are typically disposed at the proximal end of the one or more lead bodies106for connection to corresponding conductive contacts (e.g.,214inFIG. 2A and 240ofFIG. 2C) in connectors (e.g.,144inFIGS. 1-2Aand222and250ofFIG. 2C) disposed on, for example, the control module102(or to other devices, such as conductive contacts on a lead extension, an operating room cable, a splitter, or an adaptor). Conductive wires (not shown) extend from the terminals (e.g.,210inFIG. 2A and 236ofFIG. 2C) to the electrodes134. Typically, one or more electrodes134are electrically coupled to a terminal (e.g.,210inFIG. 2A and 236ofFIG. 2C). In some embodiments, each terminal (e.g.,210inFIG. 2A and 236ofFIG. 2C) is only connected to one electrode134. The conductive wires may be embedded in the non-conductive material of the lead or can be disposed in one or more lumens (not shown) extending along the lead. In some embodiments, there is an individual lumen for each conductive wire. In other embodiments, two or more conductive wires may extend through a lumen. There may also be one or more lumens (not shown) that open at, or near, the proximal end of the lead, for example, for inserting a stylet rod to facilitate placement of the lead within a body of a patient. Additionally, there may also be one or more lumens (not shown) that open at, or near, the distal end of the lead, for example, for infusion of drugs or medication into the site of implantation of the paddle body104. In at least one embodiment, the one or more lumens may be flushed continually, or on a regular basis, with saline, epidural fluid, or the like. In at least some embodiments, the one or more lumens can be permanently or removably sealable at the distal end.

In at least some embodiments, leads are coupled to connectors disposed on control modules.FIG. 2Ais a schematic perspective view of one embodiment of the one-port connector144disposed on the control module102.FIG. 2Bis a schematic perspective view of one embodiment of a two-port connector201disposed on the control module102. One or more leads208are shown configured and arranged for insertion to the control module102. The connector144includes a connector housing202. The connector housing202defines at least one port204into which a proximal end206of the one or more leads208with terminals210can be inserted, as shown by directional arrows212. The connector housing202also includes a plurality of conductive contacts214within each port204. When the one or more leads208are inserted into the port204, the conductive contacts214can be aligned with the terminals210on the lead(s)208to electrically couple the control module102to the electrodes (134ofFIG. 1) disposed at a distal end of the one or more leads208. Examples of connectors in control modules are found in, for example, U.S. Pat. No. 7,244,150 and U.S. Patent Application Publication No. 2008/0071320 A1, which are incorporated by reference.

It will be understood that the control module102may have any suitable number of ports including, for example, one, two, three, four, five, six, seven, eight, or more ports. It will also be understood that each of the ports can have any number of conductor contacts214disposed in the port. For example, in at least some embodiments, the control module has four ports, with eight conductive contacts214disposed in each port to define a 32-channel control module, which may be an implantable pulse generator for generating electrical pulses.

InFIG. 2C, a connector222is disposed on a lead extension224. The connector222is shown disposed at a distal end226of the lead extension224. The connector222includes a connector housing228. The connector housing228defines at least one port230into which a proximal end232of a lead234with terminals236can be inserted, as shown by directional arrow238. The connector housing228also includes a plurality of conductive contacts240. When the lead234is inserted into the port230, the conductive contacts240disposed in the connector housing228can be aligned with the terminals236on the lead234to electrically couple the lead extension224to the electrodes (134ofFIG. 1) disposed at a distal end (not shown) of the lead234.

In at least some embodiments, the proximal end of a lead extension is similarly configured and arranged as a proximal end of a lead. The lead extension224may include a plurality of conductive wires (not shown) that electrically couple the conductive contacts240to a proximal end248of the lead extension224that is opposite to the distal end226. In at least some embodiments, the conductive wires disposed in the lead extension224can be electrically coupled to a plurality of terminals (not shown) disposed on the proximal end248of the lead extension224. In at least some embodiments, the proximal end248of the lead extension224is configured and arranged for insertion into a connector disposed in another lead extension. In other embodiments, the proximal end248of the lead extension224is configured and arranged for insertion into a connector disposed in a control module. As an example, inFIG. 2Cthe proximal end248of the lead extension224is inserted into a connector250disposed in a control module252.

Stimulation patterns may be affected by the relative center-to-center spacing (in any direction) between adjacent electrodes of the paddle body. Thus, the center-to-center spacing between adjacent electrodes may affect patient stimulation. For example, a particular center-to-center electrode spacing may enhance a given therapy, while a different center-to-center electrode spacing may lessen the therapy, or may cause an undesired side-effect. At least some conventional paddle leads are formed with a fixed center-to-center spacing between adjacent electrodes. Since different therapies may benefit from different center-to-center electrode spacing, it may be useful to design a paddle lead with more than a single, fixed center-to-center spacing between adjacent electrodes.

As herein described, the paddle body includes adjustable center-to-center spacing between adjacent electrodes. In at least some embodiments, the paddle body includes electrodes disposed between pleats coupled together in an accordion-like manner, where the pleats can be expanded or contracted to adjust the center-to-center spacing between adjacent electrodes. In at least some embodiments, the paddle body includes electrodes disposed on telescoping elements, where the telescoping elements can be expanded or retracted relative to one another to adjust the center-to-center spacing between adjacent electrodes. In at least some embodiments, the paddle body includes electrodes disposed on elongated members that are slidably-coupled to one another, where the elongated members can be slid relative to one another to adjust the center-to-center spacing between adjacent electrodes. In at least some embodiments, the paddle body includes electrodes coupled to plates that can be slid relative to one another, where the plates can be slid to adjust the center-to-center spacing between adjacent electrodes. In at least some embodiments, the paddle body includes electrodes coupled to elongated members formed from shape memory material that can be activated to transition between bent configurations and straight configurations, where the elongated members can be activated to adjust the center-to-center spacing between electrodes.

FIG. 3is a schematic top close-up view of one embodiment of the paddle body104. The paddle body104has a distal end302and a proximal end304. The paddle body104includes electrodes, such as electrode134. In at least some embodiments, the electrodes134are arranged into columns of spaced-apart electrodes134, such as column350, that extend along axes parallel to a longitudinal axis306of the paddle body104. InFIG. 3, the paddle body104is shown having two columns. It will be understood that the paddle body104can have any suitable number of columns including, for example, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, or more columns. In at least some embodiments, the electrodes134are arranged into rows of spaced-apart electrodes, such as row360, that extend along axes perpendicular to the longitudinal axis306of the paddle body104. InFIG. 3, the paddle body104is shown having eight rows. It will be understood that the paddle body104can have any suitable number of rows including, for example, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, or more columns.

In at least some embodiments, the paddle body104is configured and arranged such that center-to-center spacing between adjacent rows of electrodes134(“longitudinal spacing”) is adjustable. In at least some embodiments, the paddle body104is configured and arranged such that center-to-center spacing between adjacent columns of electrodes134(“lateral spacing”) is adjustable. In at least some embodiments, the paddle body104is configured and arranged such that both longitudinal and lateral spacing of electrodes are adjustable.

In at least some embodiments, the electrodes134can be disposed on either side of regions that can be either expanded, or contracted, or both (“expandable regions”). In at least some embodiments, the expandable regions include pleats coupled together in an accordion-like manner. Any suitable number of pleats can be coupled together to form any suitable amount of potential expansion of the expandable regions.

FIG. 4Ais a schematic top view of one embodiment of the distal end302of the paddle body104. The paddle body104includes expandable regions401-403disposed between electrodes134. InFIG. 4A, the expandable regions401-403are shown as pleats coupled together in an accordion-like manner. The pleats can be formed from any flexible, non-conductive material suitable for implantation (e.g., silicone, polyurethane, or the like). In at least some embodiments, the pleats are configured and arranged to discourage attachment of fibrotic tissue thereon. In at least some embodiments, the pleats are smooth. In at least some embodiments, the pleats are formed such that the pleats do not extend outwardly beyond an outer surface404of the paddle body104.

Any suitable number of expandable regions401-403can be disposed on the paddle body104. The expandable regions401-403can be disposed at any suitable location on the paddle body104. In at least some embodiments, one or more expandable regions401-403are disposed between adjacent rows of electrodes134. In at least some embodiments, one or more expandable regions401-403are disposed between each row of the electrodes134. It will be understood that one or more expandable regions401-403can alternately be used to adjust the lateral spacing of the electrodes134in lieu of being used to adjust the longitudinal spacing of the electrodes134. For example, in at least some embodiments, the one or more expandable regions401-403are disposed between adjacent columns of the electrodes134.

InFIG. 4A, each of the expandable regions401-403is disposed between two adjacent rows of the electrodes134. The one or more expandable regions401-403include at least a contracted position and an expanded position. InFIG. 4A, the expandable regions401-403are each shown in contracted positions. When the expandable regions401-403are disposed between adjacent rows of the electrodes134and the expandable regions401-403are in contracted positions, the electrodes134of the adjacent rows have a first longitudinal center-to-center spacing410between the electrodes134of corresponding columns.

FIG. 4Bis a schematic top view of one embodiment of the distal end302of the paddle body104. InFIG. 4B, the expandable regions401and402are shown in expanded positions, while the expandable region403remains in the contracted position. Consequently, the electrodes134of the rows flanking the expandable regions401and402each have a second longitudinal center-to-center spacing410′ between the electrodes134of corresponding columns that is greater than the first longitudinal center-to-center spacing410between the electrodes134of corresponding columns, as shown for the electrodes134of the rows flanking the expandable region403. It will be understood that the expanded regions401-403can be expanded to lengths that are anywhere between the expanded positions shown by expandable regions401and402and the contracted region shown by expandable region403. For example, one or more of the expandable regions401-403can be configured into partially-expanded configurations.

In at least some embodiments, the expandable regions401-403can be locked in at least one of the contracted position or the expanded position. In at least some embodiments, conductive wires disposed within the paddle body104are arranged such that the conductive wires withstand expansion and contraction of the expandable regions401-403without unduly stretching. For example, in at least some embodiments one or more portions of the conductive wires are disposed in the paddle body104in an accordion-like, coiled, or serpentine-like manner.

Expansion or contraction of the expandable regions401-403can be performed either manually or by an automated mechanism. In at least some embodiments, expansion or contraction of the expansion regions401-403can be performed using one or more fluids (e.g., air, saline solution, water, liquid glue, epoxy, or the like). In at least some embodiments, the expansion regions401-403include a plurality of layers of material separated from one another by a gap configured and arranged to receive the one or more fluids. In at least some embodiments, at least one of the expansion regions401-403includes a port430configured and arranged for injecting (or removing) fluid into (or from) one or more of the expansion regions401-403to transition one or more of the expansion regions401-403between the contracted position and the expanded position. In at least some embodiments, each of the expansion regions401-403includes the port430to individually control transitioning between the contracted position and the expanded position. In at least some embodiments, one port430can be used to collectively control transitioning between the contracted position and the expanded position for each of the expansion regions401-403.

In at least some embodiments, the electrodes134can be disposed on elements that can be slid relative to one another such that the elements either extend or retract relative to each other (“telescoping elements”). In at least some embodiments, at least one of the plurality of telescoping elements is configured and arranged to retract relative to another of the telescoping elements such that the telescoping elements at least partially nest with one another. In at least some embodiments, the telescoping elements can be disposed in either a contracted (retracted) position or an expanded position.

FIG. 5is a schematic top view of one embodiment of the distal end302of the paddle body104. The paddle body104includes a plurality of axially interconnected telescoping elements501-504. At least one of the telescoping elements501-504is configured and arranged to at least partially nest with at least one adjacent telescoping element of the plurality of telescoping elements501-504.

In at least some embodiments, at least one row of the electrodes134is disposed on each of the telescoping elements501-504. In at least some embodiments, a single row of the electrodes134is disposed on each of the telescoping elements501-504. In at least some embodiments, the telescoping elements501-504include a distal telescoping element501and a proximal telescoping element504. InFIG. 5, the paddle body104includes two middle telescoping elements502and503disposed between the distal telescoping element501and the proximal telescoping element504. It will be understood that the paddle body104may include any number of middle telescoping elements502and503. Alternatively, in at least some embodiments, the paddle body104may not include any middle telescoping elements502and503.

The telescoping elements501-504each include a distal portion510and a proximal portion512. In at least some embodiments, the telescoping elements501-504are configured and arranged such that the distal portion510of a given telescoping element501-504nests with the proximal portion512of the immediately-distal telescoping element501-504. In at least some embodiments, the distal portions510of the middle telescoping elements502and503and the proximal telescoping element504include a deformable distal end514configured and arranged to receive the proximal portion512of the immediately-distal telescoping element. For example, the distal end514of the telescoping element503is configured and arranged to receive the proximal portion512of the telescoping element502. In at least some embodiments, the proximal portions512of the telescoping elements501-503are configured and arranged to at least partially nest within the distal portions510of the immediately-proximal telescoping element502-504.

In at least some embodiments, the row of electrodes134disposed on the telescoping elements501-504are disposed on the distal portion512of the telescoping elements501-504. In at least some embodiments, the proximal portions512of the one or more telescoping elements are shaped to mate with the bendable distal ends514of the distal portions510of proximally-adjacent telescoping elements501-504such that, when the telescoping elements501-504are slid axially apart from one another along the longitudinal axis306of the paddle body104, the bendable distal ends514bend outwardly (laterally) in directions roughly perpendicular to the longitudinal axis306of the paddle body104.

In at least some embodiments, the telescoping elements501-504include one or more latching mechanisms, such as latching mechanism520, that enable the telescoping elements501-504to lock in place when expanded to the expanded position. In a least some embodiments, the telescoping elements501-504include one or more anchoring elements530(e.g., an aperture, a protuberance, a hook, or the like) disposed at the distal end302of the paddle body104, or the proximal end of the paddle body104, or both. In at least some embodiments, the one or more anchoring elements530provide one or more locations for attaching the paddle body104(either directly or indirectly via wire, or the like) to a patient during implantation. Attaching the paddle body104to the patient via the one or more anchoring elements530can prevent lead migration over time. Additionally, when the paddle body104is implanted into the patient in the expanded position, attaching the paddle body104to the patient via the one or more anchoring elements530can also maintain the paddle body104in the expanded position throughout the implanted lifetime of the paddle body104within the patient. Furthermore, when the paddle body104is implanted into the patient in the expanded position, attaching the paddle body104to the patient via the one or more anchoring elements530can also provide temporary anchoring (e.g., dissolving sutures, or the like).

InFIG. 5, the telescoping elements501-504are shown configured and arranged to adjust the longitudinal center-to-center spacing between rows of the electrodes134. It will be understood that the telescoping elements501-504can, instead, be configured and arranged to adjust the lateral center-to-center spacing between columns of the electrodes134. It will also be understood that the telescoping elements501-504can be extended or retracted such that the center-to-center spacing between electrodes134is anywhere between the extended and retracted positions.

In at least some embodiments, the electrodes134are coupled to corresponding elongated members that are slidably-coupled to one another. In at least some embodiments, sliding one, or both, of the elongated members relative to one another adjusts the center-to-center spacing of the electrodes134.FIG. 6is a schematic top view of one embodiment of the distal end302of the paddle body104. The electrodes134are coupled to support elements601-603. In at least some embodiments, the support elements601-603extend in directions that are perpendicular to the longitudinal axis306of the paddle body104.

One or more elongated members are coupled to each of the support elements601-603. For example, inFIG. 6elongated member606is coupled to the support element603and elongated member608is coupled to the support element602. At least some elongated members that are slidably-coupled to other elongated members coupled to adjacent support elements601-603. For example, inFIG. 6elongated member606is slidably-coupled to elongated member608. In at least some embodiments, slidably-coupleable elongated members, such as slidably-coupleable elongated members606and608, are coupled together via tabs, such as tabs612and614disposed on elongated members606and608, respectively. In at least some embodiments, the tabs612and614are disposed at distal ends of the slidably-coupleable elongated members606and608, respectively.

In at least some embodiments, sliding slidably-coupled elongated members relative to one another adjusts the spacing between the adjacent support bars601-603to which the slidably-coupled elongated members are coupled. Thus, sliding slidably-coupled elongated members relative to one another adjusts the longitudinal center-to-center spacing between rows of the electrodes134disposed on the support elements601-603. For example, when the slidably coupleable elongated members606and608are slid relative to one another, the distance between the support elements602and603is adjusted. Accordingly, the longitudinal center-to-center spacing between rows of the electrodes134disposed on the support elements602and603is likewise adjusted.

InFIG. 6, the slidably coupleable elongated members are shown in a contracted position. In at least some embodiments, the slidably-coupleable elongated members are configured and arranged such that, in a contracted position the longitudinal center-to-center spacing between rows of the electrodes134is no more than a length of the shortest of the two slidably-coupleable elongated members that are coupled together. In at least some embodiments, the slidably-coupleable elongated members are configured and arranged such that, in an expanded position the longitudinal center-to-center spacing between rows of the electrodes134is no more than the combined lengths of the two slidably coupleable elongated members that are coupled together.

InFIG. 6, the slidably-coupleable elongated members are shown configured and arranged to adjust the longitudinal center-to-center spacing between rows of the electrodes134. It will be understood that the slidably coupleable elongated members can, instead, be configured and arranged to adjust the lateral center-to-center spacing between columns of the electrodes134, or both rows and columns. It will also be understood that the slidably-coupleable elongated members can be slid along each other such that the center-to-center spacing between electrodes134is anywhere between an expanded or a contracted position.

In at least some embodiments, the paddle body includes electrodes coupled to plates that are slidably-coupled to one another such that sliding one, or both, of the plates relative to one another adjusts the center-to-center spacing of the electrodes134.FIGS. 7A-7Bare schematic top views of one embodiment of overlapping slidably-coupled plates702and704suitable for use with the paddle body104. The electrode134ais coupled to the plate702and the electrode134bis coupled to the plate704. The plate702includes a knob706extending from a top surface of the slidable plate702. The plate704defines a slot708extending through the plate704. The slot708defines an axis that extends between the electrodes134a-b. The slot708is configured and arranged to receive the knob706such that, when the knob706is disposed in the slot708, the knob706can be moved back and forth within the slot708along the axis of the slot708.

In at least some embodiments, the knob708is fixedly coupled to the plate702such that movement of the knob708causes a corresponding movement of the plate702.

Consequently, in at least some embodiments, movement of the knob706along the axis of the slot708causes a change in the center-to-center distance between the electrodes134a-bdisposed on the plates702and704. InFIG. 7A, the knob706is positioned on one end of the slot708such that the electrodes134have a first center-to-center distance710. InFIG. 7A, the knob706is positioned on an opposing end of the slot708such that the electrodes134have a second center-to-center distance710′ that is greater than the first center-to-center distance710.

In at least some embodiments, the plates702and704can be disposed in the paddle body104such that the plates702and704are spaced apart laterally from one another. When the plates702and704are disposed in the paddle body104such that the plates702and704are spaced apart laterally from one another, moving the knob706along the slot708from the position shown inFIG. 7Ato the position shown inFIG. 7Bcan increase the lateral center-to-center spacing between one or more columns of the electrodes134a-b.In other words, moving the knob706along the slot708from the position shown inFIG. 7Ato the position shown inFIG. 7Bcan be used to transition electrodes134within one or more rows from a contracted position to an expanded position.

FIG. 7Cis a schematic transverse cross-sectional view of one embodiment of the plates702and704disposed in the paddle body104. InFIG. 7C, the knob706is shown disposed in the slot708such that the knob706is closer to the electrode134b(i.e., the plates702and704are in a similar position as shown inFIG. 7A), indicating a contracted position. Thus, moving the knob706along the slot708toward the electrode134acauses a transition to an expanded position.

In at least some embodiments, the electrode134ahas a thickness (shown in

FIG. 7Cas two-headed arrow714) that is larger than the corresponding thickness of the electrode134b. In at least some embodiments, the electrode134ahas a thickness that is equal to the combined thicknesses of both the electrode134band the plate704.

InFIG. 7C, the slidably-coupleable plates702and704are shown configured and arranged to adjust the lateral center-to-center spacing between columns of the electrodes134. It will be understood that the slidably-coupleable plates702and704can, instead, be configured and arranged to adjust the longitudinal center-to-center spacing between rows of the electrodes134. It will also be understood that the slidably-coupleable plates702and704can be used in conjunction with any of the other paddle body arrangements discussed above for adjusting both the longitudinal and the lateral center-to-center spacing between adjacent electrodes. It will also be understood that the slidably-coupleable plates702and704can be slid along each other such that the center-to-center spacing between electrodes134is anywhere between an expanded or a contracted position.

In at least some embodiments, the paddle body104includes one or more elongated members formed from one or more shape memory materials, such as nitinol (“shape memory members”). In at least some embodiment, the one or more shape memory members are coupled to an activator (e.g., an electrical source, a heat source, or the like) configured and arranged to activate (e.g., bend or straighten) the shape memory members. In at least some embodiments, the shape memory members are disposed the paddle body104in a curved configuration. In at least some embodiments, one or more of the electrodes134can be coupled to the shape memory members. In at least some embodiments, one of the electrodes134are coupled to either end of the shape memory members. In at least some embodiments, activating the activator (e.g., applying current, applying heat, or the like) causes the shape memory members to straighten. Accordingly, when electrodes134are disposed at either end of one of the shape memory members, as the shape memory member straightens the spacing between the two electrodes134may increase. In at least some embodiments, straightened shape memory members can be de-activated to re-bend, as desired.

FIG. 8Ais a schematic bottom view of one embodiment of the distal end302of the paddle body104. The paddle body104includes electrodes134a-134d.In at least some embodiments, the electrodes134aand134dform a first row and the electrodes134band134cform a second row. The rows each have a first lateral center-to-center spacing806between electrodes. In at least some embodiments, the electrodes134aand134bform a first column and electrodes134cand134dform a second column. The columns each have a first longitudinal center-to-center spacing808between electrodes. The paddle body104also includes shape memory members801-804coupling together the electrodes134a-d.

InFIG. 8A, the shape memory members801-804are each shown in bent configurations. The shape memory members801-804can be bent into any suitable shape (e.g., S-bends, arches, or the like). InFIG. 4A, the shape memory members801and804are shown with S-bends and the shape memory members802and803are shown arched. Any suitable type of bend can be used for any of the shape memory members801-804.

InFIG. 8A, each of the electrodes134a-dis shown coupled to two other of the electrodes134a-d, via the shape memory members801-804, including the electrodes134a-dof the same row and column. In at least some embodiments, each of the electrodes134a-dis coupled to only one other of the electrodes134a-dvia the shape memory members801-804. In at least some embodiments, each of the electrodes134a-dis coupled to each of the remaining electrodes134a-dvia the shape memory members801-804.

In at least some embodiments, the shape memory members can be used to adjust the center-to-center spacing between electrodes of a given row (i.e., lateral spacing). In at least some embodiments, the shape memory members can be used to adjust the center-to-center spacing between electrodes of a given row without a corresponding adjustment of the center-to-center spacing between electrodes of a given column (i.e., longitudinal spacing). In at least some embodiments, each of the electrodes134a-dof a given row are coupled together by one or more shape memory members801-804such that those electrodes134a-dare not coupled to electrodes134a-ddisposed in any other rows. For example, in at least some embodiments, the electrodes134aand134dare coupled together by shape memory member804, yet neither the electrode134anor the electrode134dis coupled to either of the electrodes134band134cvia one or more shape memory members801or803.

In at least some embodiments, the shape memory members can be used to adjust the center-to-center spacing between electrodes of a given column (i.e., longitudinal spacing). In at least some embodiments, the shape memory members can be used to adjust the center-to-center spacing between electrodes of a given column without a corresponding adjustment of the center-to-center spacing between electrodes of a given row (i.e., lateral spacing). In at least some embodiments, each of the electrodes134a-dof a given column are coupled together by one or more shape memory members801-804such that those electrodes134a-dare not coupled to electrodes134a-ddisposed in any other columns. For example, in at least some embodiments, the electrodes134aand134bare coupled together by shape memory member8014, yet neither the electrode134anor the electrode134bis coupled to either of the electrodes134cand134dvia one or more shape memory members802or804.

InFIG. 8A, the electrodes134a-dare shown coupled together by bent shape memory members801-804. Upon activation, one or more of the shape memory members801-804can be straightened, thereby increasing at least one of the lateral center-to-center spacing between two or more of the electrodes134a-dor the longitudinal center-to-center spacing between two or more of the electrodes134a-d. In at least some embodiments, once straightened, the one or more of the shape memory members801-804can be de-activated to re-bend the shape memory members801-804, thereby decreasing at least one of the lateral center-to-center spacing between two or more of the electrodes134a-dor the longitudinal center-to-center spacing between two or more of the electrodes134a-d.

FIG. 8Bis a schematic bottom view of one embodiment of the distal end302of the paddle body104. The shape memory members801-804are disposed in a straightened configuration. Accordingly, the rows of electrodes134a-deach have a second lateral center-to-center spacing806′ between electrodes134a-dthat is greater than the first lateral center-to-center spacing806, shown inFIG. 8A. Additionally, the columns of electrodes134a-deach have a second longitudinal center-to-center spacing808′ between electrodes134a-dthat is greater than the first longitudinal center-to-center spacing808shown inFIG. 8A. It will be understood that the shape memory members801-804can be formed into shapes that are anywhere between the bent configurations shown inFIG. 8Aand the straightened configurations shown inFIG. 8B. For example, one or more of the shape memory members801-804can be configured into partially-bent or partially-straightened configurations.

FIG. 9is a schematic overview of one embodiment of components of an electrical stimulation system900including an electronic subassembly910disposed within a control module. It will be understood that the electrical stimulation system can include more, fewer, or different components and can have a variety of different configurations including those configurations disclosed in the stimulator references cited herein.

Some of the components (for example, power source912, antenna918, receiver902, and processor904) of the electrical stimulation system can be positioned on one or more circuit boards or similar carriers within a sealed housing of an implantable pulse generator, if desired. Any power source912can be used including, for example, a battery such as a primary battery or a rechargeable battery. Examples of other power sources include super capacitors, nuclear or atomic batteries, mechanical resonators, infrared collectors, thermally-powered energy sources, flexural powered energy sources, bioenergy power sources, fuel cells, bioelectric cells, osmotic pressure pumps, and the like including the power sources described in U.S. Patent Application Publication No. 2004/0059392, incorporated herein by reference.

As another alternative, power can be supplied by an external power source through inductive coupling via the optional antenna918or a secondary antenna. The external power source can be in a device that is mounted on the skin of the user or in a unit that is provided near the user on a permanent or periodic basis.

If the power source912is a rechargeable battery, the battery may be recharged using the optional antenna918, if desired. Power can be provided to the battery for recharging by inductively coupling the battery through the antenna to a recharging unit916external to the user. Examples of such arrangements can be found in the references identified above.

In one embodiment, electrical current is emitted by the electrodes134on the paddle or lead body to stimulate nerve fibers, muscle fibers, or other body tissues near the electrical stimulation system. A processor904is generally included to control the timing and electrical characteristics of the electrical stimulation system. For example, the processor904can, if desired, control one or more of the timing, frequency, strength, duration, and waveform of the pulses. In addition, the processor904can select which electrodes can be used to provide stimulation, if desired. In some embodiments, the processor904may select which electrode(s) are cathodes and which electrode(s) are anodes. In some embodiments, the processor904may be used to identify which electrodes provide the most useful stimulation of the desired tissue.

Any processor can be used and can be as simple as an electronic device that, for example, produces pulses at a regular interval or the processor can be capable of receiving and interpreting instructions from an external programming unit908that, for example, allows modification of pulse characteristics. In the illustrated embodiment, the processor904is coupled to a receiver902which, in turn, is coupled to the optional antenna918. This allows the processor904to receive instructions from an external source to, for example, direct the pulse characteristics and the selection of electrodes, if desired.

In one embodiment, the antenna918is capable of receiving signals (e.g., RF signals) from an external telemetry unit906which is programmed by a programming unit908. The programming unit908can be external to, or part of, the telemetry unit906. The telemetry unit906can be a device that is worn on the skin of the user or can be carried by the user and can have a form similar to a pager, cellular phone, or remote control, if desired. As another alternative, the telemetry unit906may not be worn or carried by the user but may only be available at a home station or at a clinician's office. The programming unit908can be any unit that can provide information to the telemetry unit906for transmission to the electrical stimulation system900. The programming unit908can be part of the telemetry unit906or can provide signals or information to the telemetry unit906via a wireless or wired connection. One example of a suitable programming unit is a computer operated by the user or clinician to send signals to the telemetry unit906.

The signals sent to the processor904via the antenna918and receiver902can be used to modify or otherwise direct the operation of the electrical stimulation system. For example, the signals may be used to modify the pulses of the electrical stimulation system such as modifying one or more of pulse duration, pulse frequency, pulse waveform, and pulse strength. The signals may also direct the electrical stimulation system900to cease operation, to start operation, to start charging the battery, or to stop charging the battery. In other embodiments, the stimulation system does not include an antenna918or receiver902and the processor904operates as programmed.

Optionally, the electrical stimulation system900may include a transmitter (not shown) coupled to the processor904and the antenna918for transmitting signals back to the telemetry unit906or another unit capable of receiving the signals. For example, the electrical stimulation system900may transmit signals indicating whether the electrical stimulation system900is operating properly or not or indicating when the battery needs to be charged or the level of charge remaining in the battery. The processor904may also be capable of transmitting information about the pulse characteristics so that a user or clinician can determine or verify the characteristics.