Patent Publication Number: US-8983608-B2

Title: Lead connector for an implantable electric stimulation system and methods of making and using

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation of U.S. patent application Ser. No. 13/281,257 filed on Oct. 25, 2011, now allowed, which is a continuation of U.S. patent application Ser. No. 12/104,209 filed on Apr. 16, 2008, now U.S. Pat. No. 8,046,073 issued on Oct. 25, 2011, all of which are incorporated herein by reference. 
    
    
     TECHNICAL 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 systems that include a connector that includes connector contacts configured and arranged to couple electrically with leads having different numbers of terminals arranged in different orientations, as well as methods of making and using the connectors 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. Deep brain stimulation has also been useful for treating refractory chronic pain syndromes and has been applied to treat movement disorders and epilepsy. 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. Moreover, electrical stimulation systems can be implanted subcutaneously to stimulate subcutaneous tissue including subcutaneous nerves such as the occipital nerve. 
     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 lead-connection system includes a lead with a distal end and a proximal end. The lead includes a plurality of electrodes disposed at the distal end, a plurality of terminals disposed at the proximal end, and a plurality of conductor wires disposed along the lead to electrically couple each of the plurality of electrodes to a different one of the plurality of terminals. The lead-connection system also includes a connector configured and arranged for receiving the proximal end of the lead. The connector defines a port configured and arranged for receiving the proximal end of the lead. The connector also includes a plurality of connector contacts disposed in the connector. The number of connector contacts is greater than the number of terminals disposed on the proximal end of the lead. When the connector receives the proximal end of the lead, each of the plurality of terminals disposed on the proximal end of the lead makes electrical contact with at least one of the connector contacts of the connector and no two terminals make electrical contact with a same one of the connector contacts. 
     In another embodiment, an electrical stimulating system includes a lead having a distal end and a proximal end. The lead includes a plurality of electrodes disposed at the distal end, a plurality of terminals disposed at the proximal end, and a plurality of conductor wires coupling the plurality of electrodes electrically to the plurality of terminals. The electrical stimulating system also includes a control module configured and arranged to electrically couple to the lead. The control module includes a housing and an electronic subassembly disposed in the housing. The electrical stimulating system also includes a connector configured and arranged for receiving the proximal end of the lead. The connector defines a port configured and arranged for receiving the proximal end of the lead. The connector also includes a plurality of connector contacts disposed in the connector. The number of connector contacts is greater than the number of terminals disposed on the proximal end of the lead. When the connector receives the proximal end of the lead, each of the plurality of terminal disposed on the proximal end of the lead makes electrical contact with at least one of the connector contacts of the connector and no two terminals make electrical contact with a same one of the connector contacts. 
     In yet another embodiment, a method of implanting a lead into a patient and disposing the proximal end of the lead into a connector. The lead includes a plurality of electrodes at a distal end of the lead. The electrodes are electrically coupled to a plurality of terminals disposed on a proximal end of the lead by a plurality of contact wires. The connector defines at least one port for receiving the proximal end of the lead. The at least one port includes a plurality of connective contacts that electrically couple to at least one of the plurality of terminals where the number of connector contacts is greater than the number of terminals disposed on the proximal end of the lead and no two terminals make electrical contact with a same one of the connector contacts. The method further includes providing electrical signals from the at least one control module to electrically stimulate patient tissue using at least one of the plurality of electrodes disposed on the lead. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following drawings. In the drawings, like reference numerals refer to like parts throughout the various figures unless otherwise specified. 
       For a better understanding of the present invention, reference will be made to the following Detailed Description, which is to be read in association with the accompanying drawings, wherein: 
         FIG. 1  is a schematic view of one embodiment of an electrical stimulation system, according to the invention; 
         FIG. 2  is a schematic view of another embodiment of an electrical stimulation system, according to the invention; 
         FIG. 3A  is a schematic view of one embodiment of a proximal portion of a lead and a control module of an electrical stimulation system, according to the invention; 
         FIG. 3B  is a schematic view of one embodiment of a proximal portion of a lead and a lead extension of an electrical stimulation system, according to the invention; 
         FIG. 4  is a schematic side view of one embodiment of a connector positioned between a portion of a proximal end of an eight-terminal lead and a portion of a proximal end of a sixteen-terminal lead, the connector having connector contacts disposed in the connector that align with terminals disposed on either the eight-terminal lead or the sixteen-terminal lead when either the eight-terminal lead or the sixteen-terminal lead is inserted into the connector, according to the invention; 
         FIG. 5  is a schematic side view of a second embodiment of a connector positioned between a portion of a proximal end of an eight-terminal lead and a portion of a proximal end of a sixteen-terminal lead, the connector having connector contacts disposed in the connector that align with terminals disposed on either the eight-terminal lead or the sixteen-terminal lead when either the eight-terminal lead or the sixteen-terminal lead is inserted into the connector, according to the invention; 
         FIG. 6  is a schematic side view of a third embodiment of a connector positioned between a portion of a proximal end of an eight-terminal lead and a portion of a proximal end of a sixteen-terminal lead, the connector having connector contacts disposed in the connector that align with terminals disposed on either the eight-terminal lead or the sixteen-terminal lead when either the eight-terminal lead or the sixteen-terminal lead is inserted into the connector, according to the invention; 
         FIG. 7A  is a schematic perspective view of one embodiment of a portion of a proximal end of a lead with a round cross-sectional shape and a portion of a connector with a port with a compatible cross-sectional shape, according to the invention; 
         FIG. 7B  is a schematic perspective view of one embodiment of a portion of a proximal end of a lead with a triangular cross-sectional shape and a portion of a connector with a port with a compatible cross-sectional shape, according to the invention; 
         FIG. 7C  is a schematic perspective view of one embodiment of a portion of a proximal end of a lead with a square cross-sectional shape and a portion of a connector with a port with a compatible cross-sectional shape, according to the invention; 
         FIG. 7D  is a schematic perspective view of one embodiment of a portion of a proximal end of a lead with a semi-circular cross-sectional shape and a portion of a connector with a port with a compatible cross-sectional shape, according to the invention; and 
         FIG. 8  is a schematic overview of one embodiment of components of a stimulation system, including an electronic subassembly disposed within a control module, according to the invention. 
     
    
    
     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 systems that include a connector that includes connector contacts configured and arranged to couple electrically with leads having different numbers of terminals arranged in different orientations, as well as methods of making and using the connectors 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; and U.S. patent application Ser. Nos. 10/353,101, 10/503,281, 11/238,240; 11/319,291; 11/327,880; 11/375,638; 11/393,991; and 11/396,309, all of which are incorporated by reference. 
       FIG. 1  illustrates schematically one embodiment of an electrical stimulation system  100 . The electrical stimulation system includes a control module (e.g., a stimulator or pulse generator)  102 , a paddle body  104 , and at least one lead body  106  coupling the control module  102  to the paddle body  104 . The paddle body  104  and the one or more lead bodies  106  form a lead. The paddle body  104  typically includes an array of electrodes  134 . The control module  102  typically includes an electronic subassembly  110  and an optional power source  120  disposed in a sealed housing  114 . The control module  102  typically includes a connector  144  ( FIGS. 2 and 3A , see also  322  and  350  of  FIG. 3B ) into which the proximal end of the one or more lead bodies  106  can be plugged to make an electrical connection via connector contacts on the control module  102  and terminals (e.g.,  310  in  FIG. 3A and 336  of  FIG. 3B ) on each of the one or more lead bodies  106 . 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 electrical stimulation system references cited herein. For example, instead of a paddle body  104 , the electrodes  134  can be disposed in an array at or near the distal end of the lead body  106  forming a percutaneous lead, as illustrated in  FIG. 2 . A percutaneous lead may be isodiametric along the length of the lead. In addition, one or more lead extensions  324  (e.g.,  FIG. 3B ) can be disposed between the one or more lead bodies  106  and the control module  102  to extend the distance between the one or more lead bodies  106  and the control module  102  of the embodiments shown in  FIGS. 1 and 2 . 
     The electrical stimulation system or components of the electrical stimulation system, including one or more of the lead bodies  106 , the paddle body  104 , and the control module  102 , 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, brain stimulation, neural stimulation, spinal cord stimulation, muscle stimulation, and the like. 
     The electrodes  134  can be formed using any conductive, biocompatible material. Examples of suitable materials include metals (e.g., platinum or titanium), alloys (e.g., platinum/iridium), conductive polymers, conductive carbon, and the like, as well as combinations thereof. The number of electrodes  134  in the array of electrodes  134  may vary. For example, there can be two, four, six, eight, ten, twelve, fourteen, sixteen, or more electrodes  134 . As will be recognized, other numbers of electrodes  134  may also be used. 
     The electrodes of the paddle body  104  or one or more lead bodies  106  are typically disposed in, or separated by, a non-conductive, biocompatible material such as, for example, silicone, polyurethane, polyetheretherketone (“PEEK”), epoxy, and the like or combinations thereof. The paddle body  104  and one or more lead bodies  106  may 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 bodies  106 . The non-conductive, biocompatible material of the paddle body  104  and the one or more lead bodies  106  may be the same or different. The paddle body  104  and the one or more lead bodies  106  may be a unitary structure or can be formed as two separate structures that are permanently or detachably coupled together. 
     Terminals (e.g.,  310  in  FIG. 3A and 336  of  FIG. 3B ) are typically disposed at the proximal end of the one or more lead bodies  106  for connection to corresponding connector contacts (e.g.,  314  in  FIG. 3A and 340  of  FIG. 3B ) in connectors (e.g.,  144  in  FIGS. 1-3A  and  322  and  350  of  FIG. 3B ) disposed on, for example, the control module  102  (or to other devices, such as connector contacts on a lead extension, an operating room cable, or an adaptor). Conductor wires (not shown) extend from the terminals (e.g.,  310  in  FIG. 3A and 336  of  FIG. 3B ) to the electrodes  134 . Typically, one or more electrodes  134  are electrically coupled to a terminal (e.g.,  310  in  FIG. 3A and 336  of  FIG. 3B ). In some embodiments, each terminal (e.g.,  310  in  FIG. 3A and 336  of  FIG. 3B ) is only connected to one electrode  134 . The conductor 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 conductor wire. In other embodiments, two or more conductor 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 body  104 . 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 with connectors disposed as part of a control module. In at least some embodiments, leads are coupled with connectors disposed on lead extensions. In other embodiments, leads are coupled with connectors disposed on other devices, such as an operating room cable or an adaptor. In at least some embodiments, fastening assemblies can be used to secure a coupling of a lead with a connector. In  FIG. 3A , the connector  144  is shown disposed on the control module  102 . The connector  144  includes a connector housing  302 . The connector housing  302  defines at least one port  304  into which a proximal end  306  of a lead  308  with terminals  310  can be inserted, as shown by directional arrow  312 . The connector housing  302  also includes a plurality of connector contacts  314  for each port  304 . When the lead  308  is inserted into the port  304 , the connector contacts  314  can be aligned with the terminals  310  on the lead  308  to electrically couple the control module  102  to the electrodes ( 134  of  FIG. 1 ) disposed at a distal end of the lead  308 . Examples of connectors in control modules are found in, for example, U.S. Pat. No. 7,244,150 and U.S. patent application Ser. No. 11/532,844, which are incorporated by reference. 
     In  FIG. 3B , a connector  322  is disposed on a lead extension  324 . The connector  322  is shown disposed at a distal end  326  of the lead extension  324 . The connector  322  includes a connector housing  328 . The connector housing  328  defines at least one port  330  into which a proximal end  332  of a lead  334  with terminals  336  can be inserted, as shown by directional arrow  338 . The connector housing  328  also includes a plurality of connector contacts  340 . When the lead  334  is inserted into the port  330 , the connector contacts  340  disposed in the connector housing  328  can be aligned with the terminals  336  on the lead  334  to electrically couple the lead extension  324  to the electrodes ( 134  of  FIG. 1 ) disposed at a distal end (not shown) of the lead  334 . 
     In at least some embodiments, the proximal end of a lead extension is similarly configured and arranged to a proximal end of a lead. The lead extension  324  may include a plurality of conductive wires (not shown) that electrically couple the connector contacts  340  to a proximal end  348  of the lead extension  324  that is opposite to the distal end  326 . In at least some embodiments, the conductive wires disposed in the lead extension  324  can be electrically coupled to a plurality of terminals (not shown) disposed on the proximal end  348  of the lead extension  324 . In at least some embodiments, the proximal end  348  of the lead extension  324  is configured and arranged for insertion into a connector disposed in another lead extension. In other embodiments, the proximal end  348  of the lead extension  324  is configured and arranged for insertion into a connector disposed in a control module. For example, in  FIG. 3B  the proximal end  348  of the lead extension  324  is inserted into a connector  350  disposed in a control module  352 . Note that, when a lead includes two or more proximal ends, each proximal end can be inserted into one of a plurality of ports defined in a connector, with each port including a plurality of connector contacts. 
     Advancements in technology may create changes in electrical stimulation systems over time. Patients undergoing multiple implantations/explantations over an extended period of time may receive one or more new devices that are not readily compatible with currently-implanted devices. For example, a patient with a malfunctioning currently-implanted control module may need to undergo a subsequent surgical procedure to replace the malfunctioning control module. However, the malfunctioning control module may be designed to couple to an eight-terminal lead and the replacement control module may be designed to couple to a sixteen-terminal lead. Thus, the currently-implanted lead may not be readily compatible with the replacement control module. In some cases, an adapter may be used to couple two otherwise incompatible devices. However, conceiving, testing, and implanting an adapter may add time to a surgical procedure and add another potential source of device error or human error. 
     In at least some embodiments, a lead-connection system includes a connector that is compatible with leads having different numbers of terminals, leads having different terminal orientations, or leads having different proximal-end cross-sectional shapes. Leads may include many different numbers of terminals. For example, a lead may have one, two, three, four, eight, sixteen, thirty-two, sixty-four, or more terminals. It will be understood that leads can also have other numbers of terminals. In  FIG. 4 , and in subsequent figures, eight-terminal leads and sixteen-terminal leads are used as examples showing the compatibility of the connector for electrically coupling leads with different numbers of terminals. However, in at least some embodiments, the connector can also electrically couple leads with more or less than eight or sixteen terminals. Note that it may be advantageous to have a proximal end of a lead with terminal sizes, terminal spacing, and a cross-sectional shape that differs from the electrode sizes, electrode spacing, and the cross-sectional shape of the distal end of the lead in order distinguish leads with different distal ends for different specific applications. 
     In some embodiments, when a sixteen-terminal lead is inserted into a connector, each connector contact disposed on the connector aligns (and electrically couples) with each terminal disposed on the lead. However, when an eight-terminal lead is inserted into that same connector, every other connector contact disposed in the connector aligns (and electrically couples) with a terminal disposed on the lead. In at least some embodiments, when a proximal end of a lead with terminals is inserted into a connector with connector contacts and one or more of the terminals align with one or more of the connector contacts, the aligned connector contact(s) and terminal(s) also couple electrically to one another. 
       FIGS. 4-6  each show a different embodiment of a connector positioned between two different leads for illustrative purposes. Each connector embodiment is configured and arranged to receive a single lead that can be selected from either of the leads shown with each connector embodiment.  FIG. 4  is a schematic side view of one embodiment of a connector  402  positioned between a portion of a proximal end of an eight-terminal lead  404  and a portion of a proximal end of a sixteen-terminal lead  406 . The connector  402  includes a port  408  and connector contacts  410  disposed in a connector housing  412 . The connector contacts  410  can be grouped into sets  414 - 421  of adjacent connector contacts  410 . In  FIG. 4 , and in subsequent figures, sets are shown as including two connector contacts for clarity of illustration. Sets can include many different numbers of connector contacts. For example, sets can include two, three, four, five, six, seven, eight, nine, ten, or more connector contacts in a set. It will be understood that sets may also include other numbers of connector contacts. In  FIG. 4 , each set  414 - 421  of connector contacts  410  includes a first connector contact, such as first connector contact  424 , and a second connector contact, such as second connector contact  422 . In at least some embodiments, the designation of the first connector contacts and the second connector contacts in each set  414 - 421  of connector contacts  410  is based solely on the relative positioning of the first connector contacts and the second connector contacts within each set  414 - 421  of connector contacts  410 . 
     The eight-terminal lead  404  includes a plurality of terminals  426 , such as terminal  428 , and the sixteen-terminal lead  406  includes a plurality of terminals  430 , such as terminals  432  and  434 . Each of the connector contacts  410  in the connector  402  is configured and arranged to align (and electrically couple) with one of the plurality of terminals  430  disposed on the sixteen-terminal lead  406  when the sixteen-terminal lead  406  is inserted into the port  408 . For example, in  FIG. 4 , the first connector contact  424  and the second connector contact  422  are as shown aligned with the terminals  434  and  432 , respectively, of the sixteen-terminal lead  406 , as shown by two-headed dashed arrows  438  and  436 , respectively. Thus, in at least some embodiments, when the sixteen-terminal lead  406  is inserted into the port  408 , each connector contact  410  aligns (and electrically couples) to one of the terminals  430 . 
     However, only one connector contact of each set  414 - 421  of connector contacts  410  is configured and arranged to align (and electrically couple) with each of the plurality of terminals  426  disposed on the eight-terminal lead  404  when the eight-terminal lead  404  is inserted into the port  408 . For example, in  FIG. 4 , the first connector contact  424  aligns with the terminal  428  of the eight-terminal lead  404 , as shown by the two-headed arrow  438 . However, the second connector contact  422  does not align with any terminals of the eight-terminal lead  404 , as shown by the two-headed arrow  436 . Thus, in at least some embodiments, when the eight-terminal lead  404  is inserted into the port  408 , each of the first connector contacts aligns (and electrically couples) to one of the terminals  426  and none of the second connector contacts aligns (and electrically couples) with any of the terminals  426 . 
     In at least some embodiments, the connector  402  may include a switch, such as switch  440 , for controlling the functioning of one or more of the connector contacts. In some embodiments, the switch  440  may be used to de-activate unused connector contacts. For example, the switch  440  may have a first position and a second position. The first position may correspond to the activation of each of the connector contacts  410  and the second position may correspond to the de-activation of the second connector contacts. Thus, the switch  440  may be placed in the first position when the sixteen-terminal lead  406  is inserted into the port  408 , and placed in the second position when the eight-terminal lead  404  is inserted into the port  408 . De-activation of unused connector contacts may provide an advantage by avoiding energy waste, current leakage, and pocket stimulation within the connector  402 . In some embodiments, the switch  440  is disposed on the connector  402 . In other embodiments, the switch  440  is disposed on the control module ( 102  in  FIGS. 1-3A  and  352  in  FIG. 3B ) or is implemented through software in the control module as described below. 
     In alternate embodiments, the switch  440  may have additional positions that may de-activate different connector contacts. For example, another position may de-activate the first connector contacts, another position may de-activate the eight most distal connector contacts, another position may de-activate the eight most proximal connector contacts, another position may de-activate one or more sets of connector contacts, and another position may de-activate the first three connector contacts of every set of connector contacts. It will be understood that many other conductive-contact-de-activation combinations are possible. In an alternate embodiment, a separate on/off switch may control each individual connector contact to customize the orientation of connector contact activation. Many different types of switches may be used. For example, switches may include mechanical switches, electrical switches, and the like or combinations thereof. 
     Additionally or alternatively, a switch or switches can also be implemented in software. For example, the connector  402  (or a lead to be input to the connector  402 ) may include a feature that activates the switch instead of having a healthcare professional manually activated during implantation of an electrical stimulation system. In some embodiments, the switch is activated by one or more electronic sensors disposed in the connector  402  (or a lead to be input to the connector  402 ) or by testing properties of the lead or connector contacts (e.g., the resistance of a connector contact, which will generally be higher if a terminal is not aligned with the connector contact). In other embodiments, a software switch is activated by a healthcare professional or another by inputting a signal into a user interface of an electronic device in electrical communication with the control module or another component of the electrical stimulation system. 
     As shown in  FIG. 4 , the sizes of the connector contacts  410  disposed in the connector  402  are narrower and more closely-spaced than the terminals  426  disposed on the eight-terminal lead  404 . However, the connector contacts  410  disposed in the connector  402  are approximately equal in size and spacing to the terminals  430  disposed on the sixteen-terminal lead  406 . In some embodiments, the sizing and spacing of either or both the connector contacts  410  of the connector  402  and the terminals  430  of the sixteen-terminal lead  406  can be modified to align with one another, and collectively modified so that the first connector contact of each set  414 - 421  of connector contacts  410  aligns with one of the terminals  426  of the eight-terminal lead  404 . 
     In some embodiments, when a sixteen-terminal lead is inserted into a connector, each connector contact disposed on the connector aligns (and electrically couples) with a terminal disposed on the sixteen-terminal lead. However, when an eight-terminal lead is inserted into the connector, each connector contact within a set of connector contacts align (and electrically couple) with a terminal disposed on the eight-terminal lead. In at least some embodiments, when either an eight-terminal lead or a sixteen-terminal lead is inserted into a connector, one or more connector contacts align (and electrically couple) with each terminal. However, no more than one terminal aligns (and electrically couples) with each connector contact. 
       FIG. 5  is a schematic side view of a second embodiment of the connector  402  positioned between a portion of a proximal end of the eight-terminal lead  404  and a portion of a proximal end of the sixteen-terminal lead  406 . When the sixteen-terminal lead  406  is inserted into the connector  402 , each of the connector contacts  410  disposed on the connector  402  aligns (and electrically couples) with one of the terminals  430  disposed on the sixteen-terminal lead  406 . For example, in  FIG. 5 , the first connector contact  424  and the second connector contact  422  of the set  414  of connector contacts  410  are shown aligned with the terminals  434  and  432 , respectively, of the sixteen-terminal lead  406 , as shown by two-headed dashed arrows  504  and  502 , respectively. 
     When the eight-terminal lead  404  is inserted into the connector  402 , each connector contact of each set  414 - 421  of connector contacts  410  align (and electrically couple) with each terminal of the plurality of terminals  426  disposed on the eight-terminal lead  404 . For example, in  FIG. 5 , the first connector contact  424  and the second connector contact  422  are both shown aligned with the terminal  428  of the eight-terminal lead  404 , as shown by the two-headed dashed arrows  606  and  608 . Thus, in at least some embodiments, each terminal of a lead may align (and electrically couple) with a plurality of connector contacts. The number of connector contacts that may align (and electrically couple) with terminals disposed on an inserted lead may vary, depending on the number of connector contacts in a set of connector contacts. 
     In some embodiments, a switch may be used to de-activate one or more of a plurality of connector contacts aligning (and electrically coupling) with a given terminal. In at least some embodiments, the switch  440  de-activates all but one of the connector contacts aligning (and electrically coupling) each terminal. For example, the switch  440  can be used to de-activate either the first connector contact  424  or the second connector contact  422  of the set  414  of connector contacts  410 , both of which align with the terminal  428 . In alternate embodiments, an algorithm may be employed by a coupled processor disposed, for example, in an electrically coupled control module to determine how much current to pass through each of a plurality of connector contacts electrically coupled to an individual terminal disposed on an inserted lead. 
     In at least some embodiments, the distance between connector contacts within a set of connector contacts may not be equal to the distance between adjacent sets of connector contacts.  FIG. 6  is a schematic side view of a third embodiment of a connector  402  positioned between a portion of a proximal end of an eight-terminal lead  404  and a portion of a proximal end of a sixteen-terminal lead  406 . The connector  402  includes a plurality of sets  414 - 421  of connector contacts  410 . Each set  414 - 421  of connector contacts  410  includes a first connector contact, such as the first connector contact  424 , and a second connector contact, such as the second connector contact  422 . First connector contacts and second connector contacts are separated from one another by an intra-set distance, such as intra-set distance  602  separating the first connector contact  424  from the second connector contact  422 . Additionally, the connector contacts within a set  414 - 421  of connector contacts  410  are separated from one another by an inter-set distance, such as inter-set distance  604  separating the set  415  of connector contacts  410  from the set  416  of connector contacts  410 . In at least some embodiments, inter-set distances are greater in length than intra-set distances. For example, as shown in  FIG. 6 , the inter-set distance  604  is greater in length than the intra-set distance  602 . In other embodiments, inter-set distances and intra-set distances are approximately equal in length (as shown in  FIGS. 4 and 5 ). In yet other embodiments, intra-set distances are greater in length than inter-set distances. 
     As shown in  FIG. 6 , each of the terminals  430  disposed on the sixteen-terminal lead  406  are configured and arranged to align (and electrically couple) with one of the connector contacts  410  disposed in the connector  404 . When the sixteen-terminal lead  406  is inserted into the connector  402 , each of the connector contacts  410  disposed on the connector  402  align (and electrically couple) with one of the terminals  430  disposed on the sixteen-terminal lead  406 . For example, in  FIG. 6 , the first connector contact  424  and the second connector contact  422  are shown aligned with the terminals  434  and  432 , respectively, of the sixteen-terminal lead  406 , as shown by two-headed dashed arrows  608  and  606 , respectively. 
     When the eight-terminal lead  404  is inserted into the connector  402 , both the first connector contact and the second connector contact of each set  414 - 421  of connector contacts  410  align (and electrically couple) with each terminal of the plurality of terminals  426  disposed on the eight-terminal lead  404 . For example, in  FIG. 6 , the first connector contact  424  and the second connector contact  422  are both shown aligned with the terminal  428  of the eight-terminal lead  404 , as shown by the two-headed dashed arrows  606  and  608 . 
     In some embodiments, a switch may be used to de-activate one or more of a plurality of connector contacts aligning (and electrically coupling) with a given terminal. For example, the switch  440  can be used to de-activate either the first connector contact  424  or the second connector contact  422  of the set  414 , both of which align with the terminal  428 . In alternate embodiments, an algorithm may be employed by a coupled processor disposed, for example, in an electrically coupled control module to determine how much current to pass through each of a plurality of connector contacts electrically coupled to an individual terminal disposed on an inserted lead. 
     In at least some embodiments, a connector can be configured and arranged to receive proximal ends of leads with different cross-sectional shapes. In a preferred embodiment, a port of a connector has a cross-sectional shape that matches, or nearly matches, the cross-sectional shape of a proximal end of a lead to facilitate insertion of the lead into the connector.  FIG. 7A  is a schematic perspective view of one embodiment of a portion of a proximal end of a lead  702  with a round cross-sectional shape and a portion of a connector  704  having a port  706  with a similar round cross-sectional shape. The lead  702  includes a plurality of terminals  708  that can align (and electrically couple) with a plurality of connector contacts  710  disposed in the port  706  when the lead  702  is inserted into the connector  704 , as shown by directional arrow  712  (and as discussed above, with reference to  FIGS. 4-6 ). 
     In other embodiments, a proximal end of a lead has a cross-sectional shape that is not round.  FIG. 7B  is a schematic perspective view of one embodiment of a portion of a proximal end of a lead  714  with a triangular cross-sectional shape and a portion of a connector  716  having a port  718  with a similar triangular cross-sectional shape. The lead  714  includes a plurality of terminals  720  that can align (and electrically couple) with a plurality of connector contacts  722  disposed in the port  718  when the lead  714  is inserted into the connector  716 , as shown by directional arrow  724  (and as discussed above, with reference to  FIGS. 4-6 ). In at least some embodiments, a plurality of terminals are disposed around a lateral circumference of the lead  714 . 
       FIG. 7C  is a schematic perspective view of one embodiment of a portion of a proximal end of a lead  726  with a square cross-sectional shape and a portion of a connector  728  having a port  730  with a similar square cross-sectional shape. The lead  726  includes a plurality of terminals  732  that can align (and electrically couple) with a plurality of connector contacts  734  disposed in the port  730  when the lead  726  is inserted into the connector  728 , as shown by directional arrow  736  (and as discussed above, with reference to  FIGS. 4-6 ). In at least some embodiments, a plurality of terminals are disposed around a lateral circumference of the lead  726 . 
       FIG. 7D  is a schematic perspective view of one embodiment of a portion of a proximal end of a lead  738  with a semi-circular cross-sectional shape and a portion of a connector  740  having a port  742  with a similar semi-circular cross-sectional shape. The lead  738  includes a plurality of terminals  744  that can align (and electrically couple) with a plurality of connector contacts  746  disposed in the port  742  when the lead  738  is inserted into the connector  740 , as shown by directional arrow  748  (and as discussed above, with reference to  FIGS. 4-6 ). In at least some embodiments, a plurality of terminals are disposed around a lateral circumference of the lead  738 . 
     Proximal ends of leads may also have many other cross-sectional shapes, both regular or irregular. For example, proximal ends of leads may have cross-sectional shapes that are rectangular-shaped, oval-shaped, cross-shaped, diamond-shaped, and the like. It will be understood that proximal ends of leads may have other cross-sectional shapes as well. Additionally, ports of connectors may also have other cross-sectional shapes that match, or nearly match, the cross-sectional shapes of proximal ends of leads. Accordingly, ports of connectors may also have cross-sectional shapes that are rectangular-shaped, oval-shaped, cross-shaped, diamond-shaped, and the like. It will be understood that ports of connectors may have other cross-sectional shapes as well. 
     As discussed above, it may be advantageous to have a proximal end of a lead that has a cross-sectional shape that is different from the distal end of the lead. For example, it may be advantageous to provide a lead with a distal end having a round cross-sectional shape and a proximal end having a square cross-sectional shape. A lead having a distal end that is a different shape from a proximal end may facilitate with distinguishing between the two ends of the lead when, for example, both ends of the lead are obscured from view by tissue during a surgical procedure. Additionally, it may be an advantage to provide a lead with one or more non-circular proximal ends to dispose multiple terminals around a lateral circumference of the proximal end of the lead in order to increase terminal density without increasing the length of the connector that houses the terminals. It may also be an advantage to provide a lead with one or more non-circular proximal ends so that the proximal end of the lead can only be inserted into a connector in one or more particular orientations. 
       FIG. 8  is a schematic overview of one embodiment of components of an electrical stimulation system  800  including an electronic subassembly  810  disposed 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 source  812 , antenna  818 , receiver  802 , and processor  804 ) 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 source  812  can 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 antenna  818  or 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 source  812  is a rechargeable battery, the battery may be recharged using the optional antenna  818 , if desired. Power can be provided to the battery for recharging by inductively coupling the battery through the antenna to a recharging unit  816  external to the user. Examples of such arrangements can be found in the references identified above. 
     In one embodiment, electrical current is emitted by the electrodes  134  on the paddle or lead body to stimulate nerve fibers, muscle fibers, or other body tissues near the electrical stimulation system. A processor  804  is generally included to control the timing and electrical characteristics of the electrical stimulation system. For example, the processor  804  can, if desired, control one or more of the timing, frequency, amplitude, duration, and waveform of the pulses. In addition, the processor  804  can select which electrodes can be used to provide stimulation, if desired. In some embodiments, the processor  804  may select which electrode(s) are cathodes and which electrode(s) are anodes. In some embodiments, the processor  804  may 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 unit  808  that, for example, allows modification of pulse characteristics. In the illustrated embodiment, the processor  804  is coupled to a receiver  802  which, in turn, is coupled to the optional antenna  818 . This allows the processor  804  to receive instructions from an external source to, for example, direct the pulse characteristics and the selection of electrodes, if desired. 
     In one embodiment, the antenna  818  is capable of receiving signals (e.g., RF signals) from an external telemetry unit  806  which is programmed by a programming unit  808 . The programming unit  808  can be external to, or part of, the telemetry unit  806 . The telemetry unit  806  can 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 unit  806  may not be worn or carried by the user but may only be available at a home station or at a clinician&#39;s office. The programming unit  808  can be any unit that can provide information to the telemetry unit  806  for transmission to the electrical stimulation system  800 . The programming unit  808  can be part of the telemetry unit  806  or can provide signals or information to the telemetry unit  806  via 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 unit  806 . 
     The signals sent to the processor  804  via the antenna  818  and receiver  802  can 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 system  800  to 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 antenna  818  or receiver  802  and the processor  804  operates as programmed. 
     Optionally, the electrical stimulation system  800  may include a transmitter (not shown) coupled to the processor  804  and the antenna  818  for transmitting signals back to the telemetry unit  806  or another unit capable of receiving the signals. For example, the electrical stimulation system  800  may transmit signals indicating whether the electrical stimulation system  800  is operating properly or not or indicating when the battery needs to be charged or the level of charge remaining in the battery. The processor  804  may also be capable of transmitting information about the pulse characteristics so that a user or clinician can determine or verify the characteristics. 
     The above specification, examples and data provide a description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention also resides in the claims hereinafter appended.