Patent Publication Number: US-10307602-B2

Title: Threaded connector assembly and methods of making and using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 62/360,145, filed Jul. 8, 2016, which is incorporated herein by reference. 
    
    
     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 leads having a threaded connector assembly, as well as methods of making and using the connector assembly and the 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. Stimulation of the brain, such as deep brain stimulation, can be used to treat a variety of diseases or disorders. 
     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 connector assembly includes a lead having a lead body having a proximal portion and a distal portion. The lead body defines a longitudinal axis. The lead further includes terminals disposed along the proximal portion of the lead body and a proximal tip attached to the proximal portion of the lead body. The proximal tip defines an aperture that is non-parallel to the longitudinal axis of the lead body. The connector assembly further includes a connector having a connector body, a connector lumen, and connector contacts disposed within the connector body and adjacent the connector lumen. The connector body includes a fastener aperture proximal to all of the connector contacts and intersecting the connector lumen. The fastener aperture of the connector and aperture of the proximal tip of the lead are configured and arranged for alignment when the proximal portion of the lead body is fully received within the connector lumen. Either one or both of the aperture of the proximal tip of the lead or the fastener aperture of the connector includes internal threading. The connector assembly further includes a threaded fastener configured and arranged for insertion into the aperture of the proximal tip of the lead and the fastener aperture of the connector. The threaded fastener engages the internal threading to fasten, couple or otherwise secure the lead to the connector. 
     In at least some embodiments, the aperture of the proximal tip of the lead extends completely through the proximal tip. 
     In at least some embodiments, the connector assembly further includes an end stop disposed within the connector body and positioned to halt the insertion of the lead into the connector. The end stop can be made from a material that is more rigid than a material of the lead body. 
     In at least some embodiments, the aperture of the proximal tip is orthogonal to the longitudinal axis of the lead body. In at least some embodiments, an internal diameter of the fastener aperture is equal to an internal diameter of the aperture of the proximal tip of the lead. 
     In at least some embodiments, the fastener aperture is fully threaded. In at least some embodiments, the aperture of the proximal tip of the lead is fully threaded. In at least some embodiments, the threaded fastener is fully threaded along an outer surface of the threaded fastener. 
     In at least some embodiments, after insertion of the threaded fastener, a first end portion of the threaded fastener is in contact with an end stop disposed within the connector body and a second, opposing end portion of the threaded fastener extends out of an outer periphery of the end stop. 
     In at least some embodiments, after insertion of the threaded fastener, a first end portion of the threaded fastener is in contact with an end stop disposed within the connector body and a second, opposing end portion of the threaded fastener seated below an outer periphery of the end stop. 
     In at least some embodiments, an interface between the threaded fastener and the proximal tip provides a fluid resistant seal. In at least some embodiments, the threaded fastener may be a set screw. In at least some embodiments, a receiving portion of the proximal tip is countersunk. 
     In a further embodiment, an electrical stimulation system includes the connector assembly having the lead and the connector described above and a control module. The control module is coupleable to the electrical stimulation lead. The control module includes a housing and an electronic subassembly disposed in the housing. 
     In at least some embodiments, the electrical stimulation system further includes a lead extension coupleable to both the connector assembly and the control module. 
     In another embodiment, a lead includes a lead body and a proximal tip. The lead body includes a proximal portion and a distal portion. The lead body defines a longitudinal axis. The lead further includes a plurality of terminals disposed along the proximal portion of the lead body. The proximal tip is attached to the proximal portion of the lead body. The proximal tip defines an aperture that is non-parallel to the longitudinal axis of the lead body. At least a portion of an internal surface of the aperture is internally threaded for engagement with an externally threaded fastener. 
     In at least some embodiments, the internal surface of the aperture is fully threaded along a length of the aperture. 
     In yet another embodiment, a connector includes a connector body defining a connector lumen; and a plurality of connector contacts disposed within the connector body adjacent to the connector lumen. The connector body includes a fastener aperture located proximal to all of the connector contacts and intersecting the connector lumen. At least a portion of an internal surface of the fastener aperture is internally threaded for engagement with an externally threaded fastener. 
     In at least some embodiments, the connector further includes an end stop disposed within the connector body and positioned to halt the insertion of a proximal tip of a lead into the connector. 
    
    
     
       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 that includes a paddle lead electrically coupled to a control module, according to the invention; 
         FIG. 2  is a schematic view of one embodiment of an electrical stimulation system that includes a percutaneous lead electrically coupled to a control module, according to the invention; 
         FIG. 3A  is a schematic view of one embodiment of the control module of  FIG. 1  configured and arranged to electrically couple to an elongated device, according to the invention; 
         FIG. 3B  is a schematic view of one embodiment of a lead extension configured and arranged to electrically couple the elongated device of  FIG. 2  to the control module of  FIG. 1 , according to the invention; 
         FIG. 4A  is a schematic, perspective view of a lead with a proximal tip according to at least some embodiments of the present invention; 
         FIG. 4B  is a close-up view of the proximal tip of  FIG. 4A ; 
         FIG. 5A  is a schematic, cross-sectional, side-elevational view of a connector according to at least some embodiments of the present invention; 
         FIG. 5B  is a close-up view of the connector of  FIG. 5A ; 
         FIG. 5C  is a schematic, cross-sectional, side-elevational, close-up view of a connector assembly having the lead of  FIG. 4A  inserted into the connector of  FIG. 5A , and a threaded fastener being inserted to couple or secure the lead to the connector according to at least some embodiments of the present invention; 
         FIG. 6  is a schematic, cross-sectional, side-elevational, close-up view of a connector assembly with a threaded fastener that simultaneously seats within the proximal tip of  FIG. 4B  and within the connector of  FIG. 5A  according to at least some embodiments of the present invention; 
         FIG. 7  is a schematic, cross-sectional, side-elevational, close-up view of a connector assembly with a threaded fastener that seats solely within the proximal tip of  FIG. 4B  according to at least some embodiments of the present invention; 
         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 leads having a threaded connector assembly, as well as methods of making and using the leads and electrical stimulation systems. 
     Suitable implantable electrical stimulation systems include, but are not limited to, a least one lead with one or more electrodes disposed along a distal end of the lead and one or more terminals disposed along the 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; 6,295,944; 6,391,985; 6,516,227; 6,609,029; 6,609,032; 6,741,892; 7,244,150; 7,450,997; 7,672,734; 7,761,165; 7,783,359; 7,792,590; 7,809,446; 7,949,395; 7,974,706; 8,831,742; 8,688,235; 6,175,710; 6,224,450; 6,271,094; 6,295,944; 6,364,278; and 6,391,985; U.S. Patent Applications Publication Nos. 2007/0150036; 2009/0187222; 2009/0276021; 2010/0076535; 2010/0268298; 2011/0004267; 2011/0078900; 2011/0130817; 2011/0130818; 2011/0238129; 2011/0313500; 2012/0016378; 2012/0046710; 2012/0071949; 2012/0165911; 2012/0197375; 2012/0203316; 2012/0203320; 2012/0203321; 2012/0316615; 2013/0105071; 2011/0005069; 2010/0268298; 2011/0130817; 2011/0130818; 2011/0078900; 2011/0238129; 2011/0313500; 2012/0016378; 2012/0046710; 2012/0165911; 2012/0197375; 2012/0203316; 2012/0203320; and 2012/0203321, all of which are incorporated by reference in their entireties. 
     Examples of connector assemblies for electrical stimulation systems with leads are found in, for example, U.S. Pat. Nos. 8,849,396; 7,244,150; 8,600,507; 8,897,876; 8,682,439; U.S. Patent Applications Publication Nos. 2012/0053646; 2014/0148885; 2015/0209575; 2016/0059019; and U.S. Patent Provisional Patent Application Nos. 62/193,472; 62/216,594; 62/259,463; and 62/278,667, all of which are incorporated by reference in their entireties. 
       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  and a lead  103  coupleable to the control module  102 . The lead  103  includes a paddle body  104  and one or more lead bodies  106 . In  FIG. 1 , the lead  103  is shown having two lead bodies  106 . It will be understood that the lead  103  can include any suitable number of lead bodies including, for example, one, two, three, four, five, six, seven, eight or more lead bodies  106 . An array  133  of electrodes, such as electrode  134 , is disposed on the paddle body  104 , and an array of terminals (e.g.,  310  in  FIG. 3A-3B ) is disposed along 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, the electrodes can be disposed in an array at or near the distal end of a lead body forming a percutaneous lead. 
       FIG. 2  illustrates schematically another embodiment of the electrical stimulation system  100 , where the lead  103  is a percutaneous lead. In  FIG. 2 , the electrodes  134  are shown disposed along the one or more lead bodies  106 . In at least some embodiments, the lead  103  is isodiametric along a longitudinal length of the lead body  106 . 
     The lead  103  can be coupled to the control module  102  in any suitable manner. In  FIG. 1 , the lead  103  is shown coupling directly to the control module  102 . In at least some other embodiments, the lead  103  couples to the control module  102  via one or more intermediate devices ( 324  in  FIG. 3B ). For example, in at least some embodiments one or more lead extensions  324  (see e.g.,  FIG. 3B ) can be disposed between the lead  103  and the control module  102  to extend the distance between the lead  103  and the control module  102 . Other intermediate devices may be used in addition to, or in lieu of, one or more lead extensions including, for example, a splitter, an adaptor, or the like or combinations thereof. It will be understood that, in the case where the electrical stimulation system  100  includes multiple elongated devices disposed between the lead  103  and the control module  102 , the intermediate devices may be configured into any suitable arrangement. 
     In  FIG. 2 , the electrical stimulation system  100  is shown having a splitter  107  configured and arranged for facilitating coupling of the lead  103  to the control module  102 . The splitter  107  includes a splitter connector  108  configured to couple to a proximal end of the lead  103 , and one or more splitter tails  109   a  and  109   b  configured and arranged to couple to the control module  102  (or another splitter, a lead extension, an adaptor, or the like). 
     With reference to  FIGS. 1 and 2 , the control module  102  typically includes a connector housing  112  and a sealed electronics housing  114 . An electronic subassembly  110  and an optional power source  120  are disposed in the electronics housing  114 . A control module connector  144  is disposed in the connector housing  112 . The control module connector  144  is configured and arranged to make an electrical connection between the lead  103  and the electronic subassembly  110  of the control module  102 . 
     The electrical stimulation system or components of the electrical stimulation system, including the paddle body  104 , the one or more of the lead bodies  106 , 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 deep 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, alloys, conductive polymers, conductive carbon, and the like, as well as combinations thereof. In at least some embodiments, one or more of the electrodes  134  are formed from one or more of: platinum, platinum iridium, palladium, palladium rhodium, or titanium. 
     Any suitable number of electrodes  134  can be disposed on the lead including, for example, four, five, six, seven, eight, nine, ten, eleven, twelve, fourteen, sixteen, twenty-four, thirty-two, or more electrodes  134 . In the case of paddle leads, the electrodes  134  can be disposed on the paddle body  104  in any suitable arrangement. In  FIG. 1 , the electrodes  134  are arranged into two columns, where each column has eight electrodes  134 . 
     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 one or more lead bodies  106  and, if applicable, the paddle body  104  may be formed in the desired shape by any process including, for example, molding (including injection molding), casting, and the like. The non-conductive material typically extends from the distal ends of the one or more lead bodies  106  to the proximal end of each of the one or more lead bodies  106 . 
     In the case of paddle leads, the non-conductive material typically extends from the paddle body  104  to the proximal end of each of the one or more lead bodies  106 . Additionally, the non-conductive, biocompatible material of the paddle body  104  and the one or more lead bodies  106  may be the same or different. Moreover, 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  FIGS. 3A-3B ) are typically disposed along the proximal end of the one or more lead bodies  106  of the electrical stimulation system  100  (as well as any splitters, lead extensions, adaptors, or the like) for electrical connection to corresponding connector contacts (e.g.,  314  in  FIG. 3A ). The connector contacts are disposed in connectors (e.g.,  144  in  FIGS. 1-3B ; and  322   FIG. 3B ) which, in turn, are disposed on, for example, the control module  102  (or a lead extension, a splitter, an adaptor, or the like). Electrically conductive wires, cables, or the like (not shown) extend from the terminals to the electrodes  134 . Typically, one or more electrodes  134  are electrically coupled to each terminal. In at least some embodiments, each terminal is only connected to one electrode  134 . 
     The electrically conductive wires (“conductors”) may be embedded in the non-conductive material of the lead body  106  or can be disposed in one or more lumens (not shown) extending along the lead body  106 . In some embodiments, there is an individual lumen for each conductor. In other embodiments, two or more conductors extend through a lumen. There may also be one or more lumens (not shown) that open at, or near, the proximal end of the one or more lead bodies  106 , for example, for inserting a stylet to facilitate placement of the one or more lead bodies  106  within a body of a patient. Additionally, there may be one or more lumens (not shown) that open at, or near, the distal end of the one or more lead bodies  106 , for example, for infusion of drugs or medication into the site of implantation of the one or more lead bodies  106 . In at least one embodiment, the one or more lumens are flushed continually, or on a regular basis, with saline, epidural fluid, or the like. In at least some embodiments, the one or more lumens are permanently or removably sealable at the distal end. 
       FIG. 3A  is a schematic side view of one embodiment of a proximal end of one or more elongated devices  300  configured and arranged for coupling to one embodiment of the control module connector  144 . The one or more elongated devices may include, for example, one or more of the lead bodies  106  of  FIG. 1 , one or more intermediate devices (e.g., a splitter, the lead extension  324  of  FIG. 3B , an adaptor, or the like or combinations thereof), or a combination thereof. 
     The control module connector  144  defines at least one port into which a proximal end of the elongated device  300  can be inserted, as shown by directional arrows  312   a  and  312   b . In  FIG. 3A  (and in other figures), the connector housing  112  is shown having two ports  304   a  and  304   b . The connector housing  112  can define any suitable number of ports including, for example, one, two, three, four, five, six, seven, eight, or more ports. 
     The control module connector  144  also includes a plurality of connector contacts, such as connector contact  314 , disposed within each port  304   a  and  304   b . When the elongated device  300  is inserted into the ports  304   a  and  304   b , the connector contacts  314  can be aligned with a plurality of terminals  310  disposed along the proximal end(s) of the elongated device(s)  300  to electrically couple the control module  102  to the electrodes ( 134  of  FIG. 1 ) disposed on the paddle body  104  of the lead  103 . Examples of connectors in control modules are found in, for example, U.S. Pat. Nos. 7,244,150 and 8,224,450, which are incorporated by reference. 
       FIG. 3B  is a schematic side view of another embodiment of the electrical stimulation system  100 . The electrical stimulation system  100  includes a lead extension  324  that is configured and arranged to couple one or more elongated devices  300  (e.g., one of the lead bodies  106  of  FIGS. 1 and 2 , the splitter  107  of  FIG. 2 , an adaptor, another lead extension, or the like or combinations thereof) to the control module  102 . In  FIG. 3B , the lead extension  324  is shown coupled to a single port  304  defined in the control module connector  144 . Additionally, the lead extension  324  is shown configured and arranged to couple to a single elongated device  300 . In alternate embodiments, the lead extension  324  is configured and arranged to couple to multiple ports  304  defined in the control module connector  144 , or to receive multiple elongated devices  300 , or both. 
     A lead extension connector  322  is disposed on the lead extension  324 . In  FIG. 3B , the lead extension connector  322  is shown disposed at a distal end  326  of the lead extension  324 . The lead extension connector  322  includes a connector housing  328 . The connector housing  328  defines at least one port  330  into which terminals  310  of the elongated device  300  can be inserted, as shown by directional arrow  338 . The connector housing  328  also includes a plurality of connector contacts, such as connector contacts  340 . When the elongated device  300  is inserted into the port  330 , the connector contacts  340  disposed in the connector housing  328  can be aligned with the terminals  310  of the elongated device  300  to electrically couple the lead extension  324  to the electrodes ( 134  of  FIGS. 1 and 2 ) disposed along the lead ( 103  in  FIGS. 1 and 2 ). 
     In at least some embodiments, the proximal end of the lead extension  324  is similarly configured and arranged as a proximal end of the lead  103  (or other elongated device  300 ). The lead extension  324  may include a plurality of electrically 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 along 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 (or another intermediate device). In other embodiments (and as shown in  FIG. 3B ), the proximal end  348  of the lead extension  324  is configured and arranged for insertion into the control module connector  144 . 
     Coupling a neuromodulation lead to a receptacle is generally accomplished using a conventional system that includes a set block and set screw mechanism. The conventional system may have a relatively large lateral profile (e.g., a spatial envelope as defined radially outward from a longitudinal axis of the lead) as compared to a lateral profile of the lead. In some clinical applications, for example, it may be preferred to have a smaller or reduced lateral profile for the lead and receptacle interface, as compared to the conventional system, to enhance patient comfort and provide clinical efficacy. 
     In at least some embodiments of the present invention, an alternative connector assembly utilizes a lead and a connector, which may be part of a lead extension, for example. The lead includes a proximal tip having a threaded proximal tip aperture that is non-parallel to a longitudinal axis of the lead or lead lumen, and preferably perpendicular or orthogonal to a longitudinal axis of the lead or lead lumen. The connector includes a fastener aperture that can be aligned with the proximal tip aperture. A threaded fastener, which may take the form of a set screw or threaded pin, is insertable into the proximal tip aperture and into the fastener aperture to affix or otherwise secure the lead to the connector while achieving a low or reduced lateral profile of the overall connector assembly. 
       FIGS. 4A and 4B  show a schematic, perspective view of a lead  400  having a proximal array  402 , a proximal tip  404  with a proximal tip aperture  406  and a lead lumen  408 . A plurality of terminals (e.g.,  310  in  FIGS. 3A-3B ) are disposed along the proximal array  402 . In at least some embodiments, the lead lumen  408  extends completely through both the proximal array  402  and the proximal tip  404  and further defines a lead lumen axis  410 . The lead lumen  408  may function as an ingress and egress opening for a guide such as a stylet. By way of example, the lead lumen  408  may facilitate passage of the stylet through both the proximal array  402  and the proximal tip  404 . 
     The terminals of the proximal array  402  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 terminals themselves can 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. In at least some embodiments, one or more of the terminals are formed from one or more of: platinum, platinum iridium, palladium, palladium rhodium, or titanium. 
     The proximal tip  404  may be made from a variety of materials such as, but not limited to, the same material as the proximal array  402  (e.g., the lead body or a material that is more rigid than the proximal array  402 ). By way of example, a more rigid material may take the form of a metallic, composite or plastic material. The proximal tip  404  may also be referred to as a connector set block or “in-lead” block. 
     In at least some embodiments, the proximal tip aperture  406  functions as an opening to receive the threaded fastener, which will be described in more detail with respect to  FIGS. 6 and 7 . The proximal tip aperture  406  defines an aperture axis  412  that is non-parallel to the lead lumen axis  410 . In at least some other embodiments, the aperture axis  412  is perpendicular or orthogonal to the lead lumen axis  410 . Additionally or alternatively, the proximal tip aperture  406  includes internal threads that extend at least partially or fully along an inner surface defining the proximal tip aperture  406 . The internal threads may be configured to provide some degree of sealing to reduce or prevent bodily fluids from entering into the lead lumen  410 . By way of example, the internal threads may be coated with a fluid resistant material, the internal threads may be compressible when the threaded fastener is torqued into the proximal tip aperture  406 , or some combination thereof. 
       FIGS. 5A through 5C  show a connector  500  having a connector body  502 , a plurality of terminal contacts  504 , a connector lumen  505  ( FIG. 5A ), an optional end stop  506 , and a fastener aperture  508 . In at least some embodiments, the plurality of terminal contacts  504  are disposed within the connector body  502  adjacent to the connector lumen  505  and in an arrangement that coincides with the terminals of the lead. The connector body  502  can be made from a non-conductive, biocompatible material similar to or the same as the portions of the proximal array  402  that separate the various terminals. Likewise, the terminal contacts  504  can be made from a conductive, biocompatible material similar to or the same as the terminals of the proximal array  402 . 
     For purposes of the description herein, the connector  500  includes the end stop  506  embedded within the connector body  502 . However, and at least in some embodiments, the connector  500  may not include the end stop and the various openings and other features associated with the end stop  506  could be applied directly and solely to the connector body  502 . 
     In the illustrated embodiment, the end stop  506  is located at a proximal end of the connector  500 . In at least some embodiments, the end stop  506  may be made from a variety of materials such as, but not limited to, the same material as the connector body  502  or a material that is more rigid than the connector body  502 . By way of example, a more rigid material may take the form of a metallic, composite or plastic material. 
     In at least some embodiments, a fastener aperture  508  extends through at least a portion of the connector body  502  and a portion of the end stop  506 . In other embodiments, the fastener aperture  508  extends completely through at least one of the connector body  502 , the end stop  506 , or both. The connector body  502  defines a connector axis  510  ( FIG. 5B ). The fastener aperture  508  defines a fastener aperture axis  512  ( FIG. 5B ). In at least some embodiments, the fastener aperture axis  512  is non-parallel or otherwise skewed relative to the connector axis  510 . In at least some other embodiments, the fastener aperture axis  508  is perpendicular or orthogonal to the connector axis  510 . Additionally or alternatively, the fastener aperture  508  includes internal threads that extend at least partially or completely (e.g., fully) along an inner surface defining the fastener aperture  508  as it extends through both the connector body  502  and the end stop  506 . The internal threads may be configured to provide some degree of sealing to reduce or prevent bodily fluids from entering into the connector body  502 . By way of example, the internal threads may be coated with a fluid resistant material, the internal threads may be compressible when the threaded fastener is torqued into the fastener aperture  508 , or some combination thereof. 
     Referring specifically to  FIG. 5C , a threaded fastener  514  can be inserted into the fastener aperture  508  of the connector  500  and into the proximal tip aperture  406  of the lead  400  once the apertures  508 ,  406  are brought into alignment. In at least some embodiments, alignment of the apertures  508 ,  406  can be accomplished by (1) inserting the lead  400  into the connector body  502  until an end portion of the proximal tip  404  contacts the end stop  506 ; and (2) rotating the lead  400  to bring the apertures  508 ,  406  into alignment. In some embodiments, the lead  400  and the connector  500  may include a feature or features that would permit the apertures  508 ,  406  to be aligned without visual confirmation, whether via direct (e.g., eyeball) or indirect (e.g., camera or scope) line-of-sight. By way of example, the lead  400  and the connector  500  can be “keyed” such that the “keying” features could engage to indicate alignment of the apertures  508 ,  406 . 
     In at least some embodiments, the fastener aperture  508  is not threaded, the proximal tip aperture  406  is threaded, and the threaded fastener  514  includes threads that coincide with the threaded proximal tip aperture  406 . In an alternate embodiment, the fastener aperture  508  is threaded, the proximal tip aperture  406  is not threaded, and the threaded fastener  514  includes threads that coincide with the threaded fastener aperture  508 . It is appreciated that if the fastener aperture  508  is threaded, but the proximal tip aperture  406  is not threaded, then the threaded fastener  514  is preferably made long enough to engage and remain engaged with the fastener aperture  508  threads even when the threaded fastener is fully seated. 
     In at least some embodiments, the internal diameter of the fastener apertures  508  is equal to an internal diameter of the proximal tip aperture  406 . If either of the apertures  508 ,  406  is threaded, for purposes of comparing the internal diameters of the apertures, the internal diameter of a threaded aperture is the diameter measured between threads (e.g., the largest diameter of the aperture or the diameter of the aperture in absence of the threading). 
       FIG. 6  shows an embodiment of a connector assembly  600  in which a threaded fastener  601 , after tightening, simultaneously seats within or otherwise fills at least part of both the proximal tip aperture  406  of the lead  400  and the fastener aperture  508  of the connector  500 . In this embodiment, the threaded fastener  601  prevents the withdrawal of the lead  400  from the connector  500 . In at least some embodiments, a head portion  602  of the threaded fastener  601  extends beyond a periphery of the proximal tip  404  by a first distance  604 . In addition, a leading portion  606  of the threaded fastener  601  contacts the end stop  506 . Additionally or alternatively, the connector body  502 , in a vicinity of the insertion point of the fastener aperture  508 , may include a beveled or countersunk feature  608 . 
       FIG. 7  shows another embodiment of a connector assembly  700  in which a different sized fastener  701 , after tightening, seats solely within the proximal tip  404  such that a head portion  702  of the set screw  701  remains clear of the fastener aperture  508  of the connector  500 . In at least some embodiments, the tightened fastener  701  bears against an inside surface of the end stop  506  to urge a surface of the proximal tip  404  against an adjacent surface of the end stop  506 . The contact pressure generated by such contact between the proximal tip  404  and the end stop  606  provides an amount of friction that is sufficient to hold or secure the lead  400  in place relative to the connector  500 . The amount of friction may be dependent on a number of factors such as, but not limited, the materials of the contacting members, the surface roughness of the contacting members, the amount of torque applied to the set screw, an optional interference fit between the set screw and the connector body, or any combination thereof. 
       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, a power source  812 , an antenna  818 , a receiver  802 , and a 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. Pat. No. 7,437,193, 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. The 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, strength, 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  selects which electrode(s) are cathodes and which electrode(s) are anodes. In some embodiments, the processor  804  is 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 the 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 the 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 the 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 provides a description of the structure, manufacture, and use 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.