Abstract:
A connector for an electrostimulation lead includes a connector housing defining a fastener aperture, a septum disposed over the fastener aperture, and a fastener for mating with the fastener aperture to secure a received lead to the connector housing so that at least one terminal disposed on the received lead electrically couples with at least one conductor contact disposed in the connector housing. The septum includes a septum flap and an attachment cuff. The septum flap is configured and arranged for extending over the fastener aperture and for receiving a tool for folding the septum flap open to expose the fastener aperture. The attachment cuff is configured and arranged for coupling the septum flap to the connector housing. The fastener is configured and arranged to be disposed in the fastener aperture and to be tightened against the lead to hold the lead within the connector housing.

Description:
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 septum covering a fastener assembly disposed on a connector coupling two or more implanted components of an electrical stimulation system, as well as methods of making and using the connectors, septa, 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 connector for receiving an electro-stimulation lead includes a connector housing, a plurality of connector contacts, a septum, and a fastener. The connector housing defines an opening for receiving a proximal end of the lead. The connector housing also includes a fastener aperture configured and arranged for receiving the fastener for securing the received lead in the connector housing. The plurality of connector contacts are disposed in the connector housing and are configured and arranged to couple to at least one terminal disposed on the proximal end of the lead. The septum is disposed on the connector housing. The septum includes a proximal end and a distal end and includes a septum flap and an attachment cuff. The septum flap is configured and arranged for extending over the fastener aperture and for receiving a tool for folding the septum flap open to expose the fastener aperture. The attachment cuff is configured and arranged for coupling the septum flap to the connector housing. The proximal end of the septum flap is attached to the proximal end of the attachment cuff and the distal end of the septum flap overhangs the distal end of the attachment cuff to receive the tool for folding the septum flap open. The fastener is configured and arranged to be disposed in the fastener aperture and to be tightened against the lead to hold the lead within the connector housing. 
     In another embodiment, an electrical stimulating system includes a lead, a control module, and a connector. The lead has a proximal end and a distal end and includes a plurality of electrodes disposed on the distal end of the lead, a plurality of terminals disposed on the proximal end of the lead, and a plurality of conductor wires extending along the lead to couple the electrodes electrically to the terminals. The control module is configured and arranged to electrically couple to the lead. The control module includes a housing, and an electronic subassembly disposed in the housing. The connector is configured and arranged for receiving the lead. The connector includes a connector housing, a plurality of connector contacts, a septum, and a fastener. The connector housing defines an opening for receiving a proximal end of the lead. The connector housing also includes a fastener aperture configured and arranged for receiving a fastener for securing the received lead in the connector housing. The plurality of connector contacts are disposed in the connector housing and are configured and arranged to couple to at least one terminal disposed on the proximal end of the lead. The septum is disposed on the connector housing. The septum includes a proximal end and a distal end and includes a septum flap and an attachment cuff. The septum flap is configured and arranged for extending over the fastener aperture and for receiving a tool for folding the septum flap open to expose the fastener aperture. The attachment cuff is configured and arranged for coupling the septum flap to the connector housing. The proximal end of the septum flap is attached to the proximal end of the attachment cuff and the distal end of the septum flap overhangs the distal end of the attachment cuff to receive the tool for folding the septum flap open. The fastener is configured and arranged to be disposed in the fastener aperture and to be tightened against the lead to hold the lead within the connector housing. 
     In yet another embodiment, a method for stimulating patient tissue includes implanting a lead into a patient, disposing a proximal end of the lead into a connector electrically coupled to a control module, and providing electrical signals from the control module to electrically stimulate patient tissue using at least one of a plurality of electrodes disposed on a distal end of the lead. The plurality of electrodes are electrically coupled to at least one terminal disposed on the proximal end of the lead. The connector includes at least one connective contact that electrically couples to at least one of the terminals of the lead. The connector also includes a fastener aperture and a septum. The fastener aperture is configured and arranged for receiving a fastener for securing the lead to the connector. The septum is disposed on the connector and extends over the fastener aperture. The septum includes an attachment cuff and a septum flap. The attachment cuff is configured and arranged for coupling to the connector. The septum flap is coupled to the attachment cuff and configured and arranged for receiving a tool to fold back the septum flap to facilitate access to the fastener. 
    
    
     
       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 for an electrical stimulation system, according to the invention; 
         FIG. 4A  is a schematic perspective view of one embodiment of a septum, according to the invention; 
         FIG. 4B  is a schematic top view of one embodiment of a septum, according to the invention; 
         FIG. 5A  is a schematic perspective view of one embodiment of a septum disposed on a portion of a connector; according to the invention; 
         FIG. 5B  is a schematic end view of one embodiment of a septum disposed on a connector; according to the invention; 
         FIG. 5C  is a schematic top view of one embodiment of a septum disposed on a connector; according to the invention; 
         FIG. 5D  is a schematic side view of one embodiment of a septum disposed on a portion of a connector; according to the invention; 
         FIG. 6A  is a schematic side view of one embodiment of a fastener disposed on a connector and covered by a septum, and a tool for removing the fastener; according to the invention; 
         FIG. 6B  is a schematic side view of one embodiment of a septum flap being pried open by a tool; according to the invention; 
         FIG. 6C  is a schematic side view of one embodiment of a septum flap pried open and a fastener being removed from a connector by a tool, according to the invention; 
         FIG. 6D  is a schematic side view of one embodiment of a septum flap that is closed after a fastener is removed from a connector by a tool, according to the invention; 
         FIG. 7A  is a schematic side view of a second embodiment of a fastener disposed on a connector and covered by a septum, and a tool for removing the fastener; according to the invention; 
         FIG. 7B  is a schematic side view of a second embodiment of a septum flap being pried open by a tool; according to the invention; 
         FIG. 7C  is a schematic side view of a second embodiment of a septum flap pried open and a fastener being removed from a connector by a tool, according to the invention; 
         FIG. 7D  is a schematic side view of a second embodiment of a septum flap that is closed after a fastener is removed from a connector by a tool, 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 septum covering a fastener assembly disposed on a connector coupling two or more implanted components of an electrical stimulation system, as well as methods of making and using the connectors, septa, 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 a proximal end 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 lead body  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  (see  FIGS. 2 , and  3 A- 3 B) into which the proximal end of the lead body  106  can be plugged to make an electrical connection via conductive contacts on the control module  102  and terminals on the lead body  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  312  (see  FIG. 3B ) can be disposed between the lead body  106  and the control module  102  to extend the distance between the lead body  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 body  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, alloys, 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 lead body  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 lead body  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. The non-conductive, biocompatible material of the paddle body  104  and the lead body  106  may be the same or different. The paddle body  104  and the lead body  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 330  of  FIG. 3B ) are typically disposed at the proximal end of the lead for connection to corresponding conductive contacts (e.g.,  314  in  FIG. 3A and 344  of  FIG. 3B ) in the control module  102  (or to conductive contacts on a lead extension). Conductor wires (not shown) extend from the terminals (e.g.,  310  in  FIG. 3A and 330  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 330  of  FIG. 3B ). In at least some embodiments, each terminal (e.g.,  310  in  FIG. 3A and 330  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 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 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 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. 
     Fastener assemblies are sometimes used to secure two or more coupled components of an electrical stimulation system. For example, a fastening assembly may be used to secure a lead (or lead extension) coupled to a connector disposed as part of a control module (as shown in  FIG. 3A ) or a lead extension (as shown in  FIG. 3B ). In  FIG. 3A , the connector  144  is disposed as part of the control module  102 . The connector  144  includes a connector housing  302  that is optionally part of the housing of the control module. The connector housing  302  defines an opening  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 conductive contacts  314  and a fastener aperture  316 . When the lead  308  is inserted into the opening  304 , the conductive 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. 
     A fastener  318  can be mated with the fastener aperture  316  to form a fastener assembly  320 . The fastener assembly  320  can be used to secure the lead  308  to the control module  102 . Fasteners and fastener apertures can be made from many different metallic or ceramic materials suitable for implantation. In  FIG. 3A , the fastener  318  is shown as a set screw. However, other types of fasteners may be used as well, such as pins, posts, and the like or combinations thereof. The fastener aperture  316  may be positioned in any location along the length of connector  144 . In  FIG. 3A  and in subsequent figures, fastener apertures are shown disposed in proximity to the opening  304  of the connector for clarity of illustration. 
     In  FIG. 3B , a connector  316  is disposed on a lead extension  318 . The connector  316  is shown disposed at a distal end  320  of the lead extension  318 . The connector  316  includes a connector housing  322 . The connector housing  322  defines an opening  324  into which the proximal end  326  of the lead  328  with terminals  330  can be inserted, as shown by directional arrow  332 . The connector housing  322  also includes a plurality of conductive contacts  334  and a fastener aperture  336 . When the lead  328  is inserted into the opening  324 , the conductive contacts  334  disposed in the connector housing  322  can be aligned with the terminals  330  on the lead  328  to electrically couple the lead extension  318  to the electrodes ( 134  of  FIG. 1 ) disposed at a distal end of the lead  328 . A fastener  338  can be mated with the fastener aperture  336  to form a fastener assembly  340 , which can be used to secure the lead  328  to the lead extension  318 . 
     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 extension  318  may include a plurality of conductive wires (not shown) that electrically couple the conductive contacts  334  to a proximal end  342  of the lead extension  318  that is opposite to the distal end  320 . In at least some embodiments, the conductive wires disposed in the lead extension  318  can be electrically coupled to a plurality of terminals (not shown) disposed on the proximal end  342  of the lead extension  318 . In at least some embodiments, the proximal end  342  of the lead extension  318  is configured and arranged for insertion into a connector disposed in another lead extension. In other embodiments, the proximal end  342  of the lead extension  318  is configured and arranged for insertion into a connector disposed in a control module. As an example, in  FIG. 3B  the proximal end  342  of the lead extension  318  is inserted into a connector  344  disposed in a control module  346 . A fastener  348  is disposed in a fastener aperture  350  to secure the proximal end  342  of the lead extension  318  to the control module  342 . 
     Direct exposure to bodily fluids or tissues may cause damage to a fastener assembly disposed on a connector. Bodily fluids or tissues may corrode of one or more components of a fastener assembly, or may cause a fastener to become stuck in a fastener aperture. Additionally, when a conductive fastener is used as an active electrical element, interactions with bodily fluids or tissues may create additional electrical current pathways that may cause improper performance or failure of the electrical stimulation system which might even result in harm to a patient. 
     Shielding implanted fastener assemblies from bodily fluids or tissues can provide some degree of protection. One way to shield a fastener assembly from bodily fluids or tissues is to cover the fastener assembly with a septum. In some embodiments, a septum is integrally molded as part of a connector housing. In other embodiments, a septum is either removably or permanently disposed over a connector housing.  FIG. 4A  is a schematic perspective view of one embodiment of a septum  402 . The septum  402  includes a septum flap  404  and an attachment cuff  406 . The attachment cuff  406  is configured and arranged to be disposed on a connector housing. It will be understood that in some embodiments the attachment cuff may be part of the housing. The septum flap  404  is configured and arranged to cover a fastener aperture on a connector (see  FIG. 3A  and  FIG. 3B ). The septum  402  can be manufactured using any elastomeric, non-conductive materials suitable for implantation, including, but not limited to, silicone, urethane, silicone-urethane copolymers, and the like or combinations thereof. The septum  402  may be formed in the desired shape by any process including, for example, molding (including injection molding), casting, and the like. 
     In at least some embodiments, one or more reinforcing components may be added to the septum flap  404  to increase the durability of the septum flap  404  and also to decrease the likelihood of the septum flap  404  being damaged (e.g., punctured by a tool) which may potentially result in an inability of the septum flap  404  to form an interference fit or to impede the flow of fluid. In at least some embodiments, the one or more reinforcing components are completely encapsulated by the material of the septum flap  404 . In other embodiments, the reinforcing component may be exposed on at least one surface. Many different types of reinforcing components can added to the septum flap  404  including, for example, woven or knitted meshes, plastic sheets, molded components, metallic components, and the like or combinations thereof. In at least some embodiments, when the reinforcing component(s) includes an electrically-conductive material, the electrically-conductive material may, at most, pass through one side of the septum flap  404 . 
       FIG. 4B  is a schematic top view of the septum  402 . The septum  402  includes a distal end  408  and a proximal end  410 . The distal end  408  of the septum flap  404  overhangs the distal end  408  of the attachment cuff  406  and can be used to facilitate opening of the septum flap  404 . The attachment cuff  406  defines an access aperture  412  extending through the attachment cuff  406  and disposed beneath the septum flap  404 . In  FIG. 4B , the access aperture  412  is shown as a circular dotted line. The size and shape of the access aperture  412  can vary. In some embodiments, the access aperture  412  is approximately the same size and shape as a head of a fastener (see  FIG. 3A  and  FIG. 3B ). In other embodiments, the access aperture  412  is approximately the same size and shape as the septum flap  404  (not including the overhanging portion of the distal end). As will be seen, many different sizes and shapes can be used for the access aperture  412 , so long as the access aperture  412  is large enough that a fastener and a tool can be passed through the access aperture  412  and not larger than the overlying septum flap  404 . In at least some embodiments, the septum  402  is formed as a single component, with the proximal end  410  of the septum flap  404  attached to a portion of the proximal end  410  of the attachment cuff  406  in proximity to the access aperture  412 . In other embodiments, the septum flap  404  and the attachment cuff  406  are formed separately and the proximal end  410  of the septum flap  404  is permanently attached to a portion of the proximal end  410  of the attachment cuff  406  in proximity to the access aperture  412  subsequent to manufacture. 
       FIG. 5A  is a schematic perspective view of the septum  402  disposed on a portion of a connector  502 . The septum  402  is positioned with the septum flap  404  covering the fastener aperture (not shown in  FIG. 5A ) The distal end  408  of the septum flap  404  overhangs the distal end  408  of the attachment cuff  406 . In at least some embodiments the attachment cuff  406  is permanently attached with the underlying connector  502 . In some embodiments, the septum  402  is integrally molded onto a connector  502 . In other embodiments, the septum  402  is a separate structure from the connector  502  and is subsequently either permanently or removably disposed on the connector  502 . In at least some embodiments, the septum  402  is thermoformed to the connector  502 . In some embodiments, the attachment cuff may wrap around the connector and in other embodiments the attachment cuff may not wrap entirely around the connector. 
     In at least some embodiments, at least a portion of the septum flap  404  creates an interference fit with a portion of the connector  502 . In at least some embodiments, at least a portion of the septum flap  404  creates an interference fit with a portion of the attachment cuff  406 . In at least some embodiments, one or more of the abovementioned interference fits facilitate the prevention of fluid or tissue exposure in the region of the connector  502  beneath the septum flap  404 . 
       FIG. 5B  is a schematic end view of the septum  402  disposed on the connector  502 . The septum flap  404  is covering the region (see  FIG. 5C ) surrounding a fastener aperture  504 .  FIG. 5C  is a schematic top view of the septum  402  disposed on a portion of the connector  502 . The septum flap  404  is covering the region  506  surrounding the fastener aperture  504 . A top surface of a fastener  508  extends from the fastener aperture  504 .  FIG. 5D  is a schematic side view of the septum  402  disposed on a portion of the connector  502 . The distal end  408  of the septum flap  404  overhangs the distal end  408  of the attachment cuff  406 . As discussed below, the overhanging portion of the septum flap  404  can be used to facilitate opening of the septum flap  404  and exposing the underlying fastener (see  FIG. 5C ). 
       FIGS. 6A-6D  show one possible set of steps for using a tool to remove a fastener mated with a fastener aperture disposed in a connector housing and covered by a septum flap. In a first step, shown in  FIG. 6A , the septum  402  is shown disposed on a portion of the connector  502 . The attachment cuff  406  is coupled to the connector  502  so that the septum flap  404  covers the fastener  508  and the fastener aperture  504 , and forms an interference fit with the region  506  surrounding the fastener aperture  504 . A tool  602  is shown in  FIG. 6A  that can be inserted, as shown by directional arrow  604 , between the attachment cuff  406  and the distal end  408  of the septum flap  404 . In  FIGS. 6A-6D , the fastener  508  is shown as a set screw and the tool is shown as a hex wrench configured and arranged to mate with a head of the set screw. 
     In at least some embodiments, an optional lead-in tab  606  is disposed at the distal end  408  of the septum flap  404 . The lead-in tab  606  is configured and arranged for facilitating access to the fastener  508  with the tool  602 . In at least some embodiments, the lead-in tab  606  is configured and arranged to guide a leading end  608  of the tool  602  into a position where the leading end  608  of the tool  602  can be pivoted to pry open the septum flap  404 . For example, in one embodiment the lead-in tab  606  may include two or more protrusions disposed on the underside of the distal end  408  of the septum flap  404  that are configured and arranged to guide the leading end  608  of the tool  602  to a selected pivoting position between the septum flap  404  and the attachment cuff  406 . 
     In a second step, shown in  FIG. 6B , the tool  602  has been inserted between the distal end  408  of the septum flap  404  and the attachment cuff  406  and the tool  602  has been pivoted to pry open the septum flap  404 . The distal end  408  of the septum flap  404  is folded away from the attachment cuff  406  to expose the fastener  508 . In a third step, shown in  FIG. 6C , the tool  602  has been further pivoted to fold back the septum flap  404  enough to allow the tool  602  to be mated with the fastener  508  and used to partially remove the fastener  508  from the fastener aperture  504 . In a fourth step, shown in  FIG. 6D , the fastener  508  has been removed from the fastener aperture  504  and the fastener  508  and the tool  602  have been removed from between the septum flap  404  and the attachment cuff  406 , as shown by directional arrow  606 . Once the fastener  508  and the tool  602  are removed from the septum flap  404 , the septum flap  404  reforms an interference fit around the region  506  surrounding the fastener aperture  504 . In at least some embodiments, the steps shown in  FIGS. 6A-6D  may also be performed in reverse order to insert the  508  fastener into the fastener aperture  504 . Additionally, in at least some embodiments, the tool  602  may also be used to access the fastener  508  in order to tighten or loosen the fastener  508  within the fastener aperture  504  without inserting or removing the fastener  508  from the fastener aperture  504 . It will be understood that the complete removal of the fastener  508  may not be necessarily be needed in order to remove a coupled lead or a lead extension from the connector  502 . In at least some cases, a lead or lead extension may be removed from the connector  502  by loosening the fastener  508  within the fastener aperture  504  without completely removing the fastener  508 . 
     In at least some embodiments, a septum flap  404  may include stretchable side pieces covering one or more of sides of the septum flap  404 .  FIGS. 7A-7D  show another possible set of steps for using the tool  602  to remove the fastener  508  mated with the fastener aperture  504  disposed in the connector housing and covered by the septum flap  404 . In  FIGS. 7A-7D , the septum flap includes a side piece  702  covering a side of a septum flap  404  that stretches when the tool  602  is inserted beneath the septum flap  404 . In at least some embodiments, the side pieces  702  covering one or more of sides of the septum flap  404  are integral with the septum flap  404 . In at least some embodiments, the side pieces  702  are also integral with the attachment cuff  406 . 
     In at least some embodiments, the side pieces  702  of the septum flap  404  are less thick than the region  506  surrounding the fastener aperture  504 . It may be an advantage to have the side pieces  702  be less thick than the region  506  surrounding the fastener aperture  504  because the side pieces  702  may need to be stretched more than the region  506  surrounding the fastener aperture  504  and the region  506  surrounding the fastener aperture  504  may be more likely to be scarred or punctured by the tool  602  during tightening/loosening of the fastener  508 . 
     As discussed above, septa may be used to prevent undesirable interactions between bodily fluids or tissues and fastener assemblies used to secure coupled components of an electrical stimulation system, while still allowing subsequent access to covered fastener assemblies. A conventional septum includes a slit directly over top of a fastener assembly through which a tool may pass for accessing the underlying fastener. Because bodily fluids exert a pressure on the slit, the slit needs to have a thickness great enough to overcome the force of the bodily fluids in order to maintain a seal. In contrast, when a septum uses a septum flap and not a slit, the same fluid pressure directed in the same direction acts to press the septum flap more tightly against the connector. 
     Accordingly, the thickness of the material needed over top of a fastener assembly can be less with the septum flap  404  than with a convention slit septum. Thus, a septum with the septum flap  404  can be a smaller size than a conventional slit septum. A smaller size may be advantageous for implanting electrical stimulation systems in confined locations inside a patient. Additionally, burrowing a fastener tool through a slit formed in silicone, or similar elastomeric material, can cause damage to the walls of the slit, which may lead to degradation or loss of a seal. In contrast, using a fastener tool to pry open a septum flap formed in silicone, or similar elastomeric material, can be less harmful to the material and less likely to cause damage to the septum. 
       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, 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  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.