Patent Description:
Implantable medical devices may perform various functions that require electrical circuitry to be present within a housing of the implantable medical device. For instance, an implantable medical device may provide electrical stimulation to a patient and/or may electrically sense physiological signals of the patient. The implantable medical device is implanted at a convenient location that may be at a distance from the target site where the stimulation and/or sensing should occur. An implantable medical lead may be present to carry the electrical stimulation signals and/or the sensed physiological signals between the implantable medical device and the target site.

The implantable medical device may include a header that contains one or more lead bores into which the implantable medical lead is inserted. The header typically sits atop a primary device housing. Electrical connectors present within the lead bores are electrically coupled to circuitry within the primary device housing. A feedthrough may be present at the junction of the primary device housing and the header to allow electrical conductors to exit the primary housing and enter the header without creating leaks into the primary device housing. In this manner, the electrical signals may be passed between the circuitry of the primary device housing and the electrical connectors of the header while preventing body fluids from entering the primary device housing.

While this arrangement is effective for the purposes described above, the header sitting atop the primary device housing contributes to the overall height of the device. A given device height might be less suited to certain implantation conditions and a lesser device height may therefore be more appropriate. Documents <CIT>; <CIT> and <CIT> disclose known implantable stimulators.

Embodiments address issues such as these and others by providing implantable medical devices that have a circuit board that is positioned adjacent to structures related to the header, rather than the entire header and all related structures residing atop the primary device housing containing the circuit board. For instance, in some embodiments, the circuit board may be positioned adjacent to one or more of the lead bores of the header. Furthermore, in some embodiments, the circuit board may be positioned adjacent to the feedthroughs.

Embodiments provide an implantable medical device that comprises a housing and a header affixed to the housing, the header providing a first lead bore having a longitudinal centerline. The implantable medical device further comprises an electrical connector positioned within the first lead bore and a circuit board within the housing. The circuit board includes circuitry that is electrically coupled to the electrical connector, and the circuit board has a side providing a largest surface area of the circuit board. The side defines a first plane, the first lead bore being positioned such that a second plane is parallel to the longitudinal centerline of the first lead bore, intersects the first lead bore, intersects the circuit board, and is perpendicular to the first plane.

Embodiments provide an implantable medical device that comprises a housing that comprises a feedthrough wall that has a feedthrough aperture and the housing comprises an exterior wall adjacent the feedthrough wall. The implantable medical device further comprises a header affixed to the housing, the header providing a first lead bore having a longitudinal centerline. An electrical connector is positioned within the first lead bore and a circuit board is located within the housing where the circuit board includes circuitry. The feedthrough wall is positioned between the circuit board and the exterior wall and a feedthrough is positioned within the feedthrough aperture of the feedthrough wall. A feedthrough conductor is electrically coupled to the circuitry, where the feedthrough conductor extends from the circuit board and passes through the feedthrough. The feedthrough conductor has a bend on a side of the feedthrough opposite the circuit board, and the feedthrough conductor extends from the bend toward the electrical connector and between the feedthrough wall and the exterior wall. The feedthrough conductor is electrically coupled to the electrical connector.

Embodiments provide an implantable medical device that includes a housing comprising an exterior wall. The implantable medical device further comprises a circuit board within the housing where the circuit board includes circuitry. A header is affixed to the housing and borders the exterior wall such that a portion of the header lies directly adjacent to a portion of the exterior wall. The header provides a first lead bore having a longitudinal centerline, wherein the circuit board is positioned between the exterior wall and the first lead bore. An electrical connector is positioned within the first lead bore and is electrically coupled to the circuitry.

Embodiments provide an implantable medical device that includes a housing containing a circuit board that includes circuitry, the housing including a screw hole and the circuit board including a ground plane that is electrically coupled to a conductive portion. The implantable medical device further includes a header coupled to the housing, the header comprising a lead bore. The implantable medical device further includes an electrical connector within the lead bore and electrically coupled to the circuitry. A screw affixes the circuit board to the housing and electrically couples the ground plane to the housing by contacting the conductive portion while being present in the screw hole of the housing.

Embodiments of implantable medical devices include a circuit board that is positioned adjacent to header-related structures such as lead bores having electrical connectors, feedthrough conductors, and lead frame conductors. This allows a potentially more compact footprint than where the entire header resides atop the primary device housing so that the device may be suitable for additional implantation conditions.

<FIG> shows an example of an implantable medical system <NUM> that includes an implantable medical device <NUM> and one or more implantable medical leads <NUM>. The implantable medical device <NUM> may be one of various types. For instance, the implantable medical device <NUM> may be an example of a neurostimulator such as those for deep brain, spinal cord, pelvic, or peripheral nerve sensing and/or stimulation. Such a device may be used to deliver electrical stimulation therapy and, in some case, also deliver a therapeutic agent, to various tissue sites of a patient to treat a variety of symptoms or conditions such as chronic pain, tremor, Parkinson's disease, other movement disorders, epilepsy, urinary or fecal incontinence, sexual dysfunction, obesity, or gastroparesis. In other examples, such a device may be a cardiac device used to deliver electrical stimulation to the heart.

This example of the implantable medical device <NUM> includes three sections, a primary device housing <NUM>, a header body <NUM>, and a battery enclosure <NUM>. It will be appreciated that these sections may be modular where the header body <NUM> mounts to the primary device housing <NUM> and/or where the battery enclosure <NUM> mounts to the primary device housing <NUM>. In this example, the primary device housing <NUM> has an exterior wall panel <NUM> attached thereto, and the header body <NUM> borders the exterior wall created by panel <NUM> at the junction <NUM> as well as a notched area <NUM> of the exterior wall created by <NUM>. Alternatively, multiple of these sections may together be unitary in construction. In either case, together they form a complete device housing.

The header section <NUM> is affixed to or otherwise contiguous with the primary device housing <NUM>. In one example where the header <NUM> is constructed of a polymer, the primary device housing <NUM> may include mounting barbs to which the header section <NUM> is molded. The header section <NUM> includes electrical connectors, discussed in more detail below, that are positioned within one or more lead bores <NUM>, <NUM>. The electrical connectors are electrically connected by feedthrough conductors or other electrical pathways to circuitry present within the primary device housing <NUM>. When a proximal end of the lead <NUM> is inserted into a corresponding lead bore <NUM>, <NUM>, electrical contacts <NUM> present on the lead body <NUM> are electrically coupled to the electrical connectors. In this manner, signals may pass between the circuitry within the primary device housing <NUM> and distal electrodes located on a distal end of the lead <NUM>, where conductors within the lead <NUM> carry the signals between the proximal contacts <NUM> and the distal electrodes.

The battery enclosure <NUM> is also affixed to or otherwise contiguous with the primary device housing <NUM>. As discussed in more detail below, according to this example, the battery enclosure <NUM> and the primary device housing <NUM> may be constructed of metal such as but not limited to titanium and various grades of titanium alloys such as grade <NUM> and grade <NUM>, and various grades of stainless steel such as type <NUM> and may be welded together at the junction with exterior wall panel <NUM> if not unitary. The battery enclosure <NUM> includes the battery as well as any isolation materials that may be included to isolate the battery from the walls of the battery enclosure section <NUM>, especially where the walls of the battery enclosure section <NUM> are conductive and it is not intended for the battery enclosure section <NUM> to be directly electrically connected to the battery.

The primary device housing <NUM> houses the electrical circuitry including a circuit board and the like necessary to provide the electrical functions of the implantable medical device <NUM>. The circuitry may include a stimulation engine capable of producing stimulation pulses. The circuitry <NUM> may also or alternatively include a sensing circuit capable of receiving physiological signals.

When the primary device housing <NUM> is metal or otherwise electrically conductive, the circuitry housed within the primary device housing <NUM> is separated from the walls of the primary device housing <NUM> such as by non-conductive regions of the circuit board. Additionally, the primary device housing <NUM> may include bumpers <NUM> that may assist in holding the circuit board <NUM> in position. The circuit board <NUM> lacks any conductive material in the areas that make contact with the bumpers <NUM>.

As discussed above, an exterior wall panel <NUM> may be attached to the primary device housing <NUM>, such as by laser seam welding. The panel <NUM> of this example includes two sections, a top section <NUM> and a lower section <NUM>. Because a portion of the primary device housing <NUM> is adjacent to a portion of the header <NUM>, rather than the entire header sitting atop the entire primary device housing, the top section <NUM> has the notched area <NUM> in order to border an area <NUM> of the header <NUM> where a set screw and related grommet of the lead bore <NUM> are located. Thus, even though the primary device housing <NUM> includes space that is adjacent the first lead bore <NUM>, the set screw and grommet of area <NUM> remain accessible. The header <NUM> also includes an area <NUM> where a set screw and grommet for the lead bore <NUM> are located.

<FIG> shows the implantable medical device <NUM>' where the panel <NUM> is omitted to reveal the circuitry <NUM> including various electrical components <NUM> present on a circuit board <NUM>. The circuit board <NUM> is mounted within the primary device housing <NUM> in a space surrounded by a boundary wall <NUM> of the primary device housing <NUM>. In this example, screws <NUM>, <NUM> pass through holes in the circuit board <NUM> and engage threaded holes in the primary device housing <NUM> to secure the circuit board <NUM>. <FIG> shows the implantable medical device <NUM>' with the screws <NUM>, <NUM> omitted to reveal the holes <NUM> of the circuit board <NUM> and threaded holes <NUM>, <NUM> of the primary device housing <NUM>.

To assist in maintaining the screws <NUM>, <NUM> in a tightened position within the threaded holes <NUM>, <NUM>, the screws <NUM>, <NUM> may be constructed of the same material as the primary device housing <NUM>. The screws <NUM>, <NUM> may also be prepared in the same manner such as by annealing both. By utilizing the same material and treatments, the screws <NUM>, <NUM> and the housing <NUM> at the threaded holes <NUM>, <NUM> bind against one another. Examples of this same material include but are not limited to titanium and various grades of titanium alloys such as grade <NUM> and grade <NUM>, and various grades of stainless steel such as type <NUM>.

Additionally, the screws <NUM>, <NUM> may be used to electrically connect a ground plane of the circuit board <NUM> to the primary device housing <NUM>. In this example, the circuit board <NUM> includes conductive rings <NUM>, <NUM> that are electrically coupled to the ground plane, and these rings <NUM>, <NUM> contact the screws <NUM>, <NUM>. Thus, the ground plane is electrically connected to the primary device housing <NUM> via the contact of the screws <NUM>, <NUM> and the rings <NUM>, <NUM>.

Also shown in <FIG> and <FIG>, the circuit board <NUM> and the primary device housing <NUM> include a notch <NUM> that coincides with the notch in the panel <NUM> as is shown in <FIG>. This notch <NUM> also provides space for the set screw and grommet for lead bore <NUM> within area <NUM> to be positioned for access while the lead bore <NUM> resides adjacent to the top portion of the primary device housing <NUM> and circuit board <NUM>.

<FIG> shows the implantable medical device <NUM>' with the circuit board <NUM> omitted to reveal an upper housing wall <NUM> and a lower feedthrough wall <NUM> that are offset from each other in this example. Feedthroughs <NUM> and feedthrough conductors <NUM> are also revealed. The feedthroughs <NUM> are positioned within feedthrough holes present in the lower feedthrough wall <NUM>. These feedthrough holes <NUM> are shown in <FIG> where the feedthroughs <NUM> are omitted. The feedthroughs <NUM> provide a sealed manner of allowing the feedthrough conductors to pass from the circuit board side of the feedthrough wall <NUM> to the opposite side so that fluid ingress into the circuit board compartment through the feedthrough holes <NUM> is avoided. Additionally, the feedthroughs <NUM> may electrically isolate the feedthrough conductors from the primary device housing <NUM> for embodiments that utilize a conductive primary device housing <NUM>.

Also shown in <FIG> and <FIG>, the header body has been omitted to reveal the header-related structures present within the header <NUM>'. These structures include various components present for each lead bore <NUM>, <NUM> such as electrical connectors <NUM>, lead bore seals <NUM>, and front seals <NUM>, <NUM>. As can be seen in <FIG> and <FIG>, the electrical connectors <NUM> and seals <NUM> of the lower lead bore <NUM> are directly adjacent to the upper housing wall <NUM>, rather than sitting atop the upper housing wall <NUM>. As can also be seen in <FIG> and <FIG>, the offset of the lower feedthrough wall <NUM> from the upper housing wall <NUM> allows the feedthrough wall <NUM> and feedthroughs <NUM> to reside beneath the lead bores <NUM>, <NUM> while the upper housing wall <NUM> resides adjacent to the lead bore <NUM>.

<FIG> and <FIG> also show that the primary device housing <NUM> includes integral shoulders <NUM>. These shoulders <NUM> contain the threaded holes <NUM>, <NUM> that the screws <NUM>, <NUM> are tightened within to secure the circuit board <NUM> in place relative to the primary device housing <NUM>.

Additionally, <FIG> and <FIG> show the battery enclosure <NUM>' where one side <NUM> of the enclosure remains while the other side and the battery itself are omitted. <FIG> and <FIG> reveal that a battery connector <NUM> may be included in some embodiments to electrically interconnect battery terminals to power terminals on the circuit board <NUM>. This allows the battery to provide electrical power to the components <NUM> mounted to the circuit board <NUM> without the battery terminals being required to directly connect to the power terminals of the circuit board <NUM>. The battery connector <NUM> may mount between the circuit board <NUM> and the battery in various ways.

<FIG> shows an opposite side of the implantable medical device <NUM>. In this example, there is an exterior wall <NUM> present on this side of the primary device housing <NUM>. In this example, there is also an exterior header wall <NUM> on this side of the header <NUM>. As can be seen in <FIG> where these exterior wall panels <NUM>, <NUM> have been omitted, the extra-feedthrough portion <NUM> of feedthrough conductors <NUM> can be seen. Upon exiting the feedthrough <NUM>, the feedthrough conductor portion <NUM> makes a bend <NUM> to then extend upward toward lead frame conductor pads <NUM> where they are attached to form an electrical coupling. This bend may be said to be on a side of the feedthrough <NUM> that is opposite the circuit board <NUM> since the feedthrough conductor <NUM> enters the feedthrough <NUM> on the feedthrough side that is closest to the circuit board <NUM> and exits the other side (i.e., the "opposite side") of feedthrough <NUM> before it makes the bend.

Lead frame conductors <NUM> extend from the lead frame conductor pads <NUM> to the electrical connectors <NUM> of the lead bores <NUM>, <NUM> where they are attached via a bond <NUM> such as a weld. The lead frame conductors <NUM> carry the electrical signals between the feedthrough conductors <NUM> (<FIG>) and the electrical connectors <NUM>. The header body <NUM> of this example includes slots <NUM> that receive each of the lead frame conductors <NUM>. As the lead frame conductors <NUM> are positioned adjacently to the lead bore <NUM>, the lead frame conductors <NUM> are therefore also positioned adjacently to the upper portion of the circuitry <NUM> (<FIG>) including the upper portion of the circuit board <NUM> with the electrical connectors <NUM> and seals <NUM> of the lead bore <NUM> being positioned between the lead frame conductors <NUM> and the upper housing wall <NUM> (<FIG>) and circuitry <NUM>.

During construction of the implantable medical device <NUM>, once the connections of the lead frame conductors <NUM> have been made to the feedthrough conductors <NUM> at the pads <NUM> and to the electrical connectors <NUM> via the bonds <NUM>, the panels <NUM>, <NUM> forming exterior walls of the primary device housing <NUM> and header <NUM>, respectively, may be added. One manner of doing so is to utilize a non-conductive material such as liquid silicone rubber that can fill in the space around the feedthrough conductors <NUM> and lead frame conductors <NUM> while also forming the exterior walls of panels <NUM>, <NUM>. Even when added as two separate exterior walls <NUM>, <NUM>, the two exterior panels <NUM>, <NUM> may be bonded together and therefore appear as a single exterior panel.

Rather than adding the exterior wall panels at the same stage of manufacturing, the exterior wall panels <NUM>, <NUM> may be added in stages, where the exterior wall panel <NUM> is added once the feedthrough conductor <NUM> is bonded to the lead frame conductor <NUM>. Then the exterior wall panel <NUM> may be added at a later time once the lead frame conductor is bonded to the electrical connector <NUM>. As another alternative, the exterior header wall panel <NUM> may be added to the header <NUM> prior to the header <NUM> being attached to the primary device housing <NUM>. However, where the exterior panels are being added at the same stage, a single panel may be created as panels <NUM>, <NUM> rather than two separate panels as shown in <FIG>.

<FIG> shows a bottom perspective view of the primary device housing <NUM> to illustrate the position of the various components of the implantable medical device <NUM>. In this view, it can be seen that the order of components from back to front include the panel <NUM>, the feedthrough wall <NUM>, the circuitry <NUM> including the circuit board <NUM>, and the exterior wall panel <NUM>. This arrangement of components is further discussed below in relation to <FIG>. <FIG> also shows the battery connector <NUM> which resides beneath the feedthroughs <NUM>.

<FIG> shows a top perspective view of the battery enclosure <NUM>. The battery enclosure <NUM> of this example includes a battery <NUM> positioned between two shells <NUM>, <NUM> that are seam welded together. The battery includes a battery terminal <NUM> that connects to the batter connector <NUM>. The outer casing of the battery <NUM> may also act as a battery terminal and may connect to the battery connector <NUM>. Additionally, where the battery enclosure <NUM> is conductive but is not intended to be directly electrically connected to the battery <NUM>, then the battery <NUM> may be covered with a non-conductive material, such as a polymer cup, that isolates the battery <NUM> from the shells <NUM>, <NUM>. The shells <NUM>, <NUM> are attached to the bottom of the primary device housing <NUM> such as by a laser seam weld.

<FIG> is a cross-sectional view of the implantable medical device where the view is looking through the lead bores <NUM>, <NUM> from back to front. This view illustrates the position of the various components in this example of the implantable medical device <NUM>. Here it can be seen that from left to right there is the panel <NUM> providing the exterior wall; the feedthrough conductor <NUM>; the lower feedthrough wall <NUM> positioned directly beneath the lead bores <NUM>, <NUM>; the circuitry <NUM> including the circuit board <NUM> and electrical components <NUM>; and then the exterior wall panel <NUM>. Here it can also be seen that from left to right there is the panel <NUM>; the lead bores <NUM>, <NUM>; the upper housing wall <NUM>; the circuitry <NUM> including the circuit board <NUM> and the electrical components <NUM>; and the exterior wall panel <NUM>.

It can be appreciated from <FIG> that the device height has been reduced compared to a conventional implantable medical device that places the lead bores atop the primary device housing. Specifically, the device height in this example is reduced at least as a result of the lead bore <NUM> being adjacent to an upper portion of the circuitry <NUM> including an upper portion of the circuit board <NUM>, rather than both lead bores <NUM>, <NUM> being positioned above the circuitry <NUM>.

<FIG> shows geometric relationships that may be utilized by various embodiments of the implantable medical device <NUM>, including the example as shown in <FIG> to position the lead bore adjacent to the primary device housing <NUM> and related components. A first plane <NUM> is formed by a side of the circuit board <NUM>. A second plane <NUM> is not necessarily defined by any particular object within the implantable medical device <NUM> but instead is introduced to provide the relationships of components. The second plane provides constraints by being perpendicular to the first plane <NUM> while also intersecting both the first plane <NUM> as shown at <NUM> and also intersecting the lead bore <NUM>. The second plane <NUM> is also parallel to a longitudinal centerline <NUM> of the lead bore <NUM>. For some embodiments the second plane <NUM> may provide further constraints such as by bisecting the lead bore <NUM> through the longitudinal centerline and/or by being parallel to the longitudinal centerline <NUM> of the second lead bore <NUM>.

<FIG> further illustrates a third plane <NUM>. Like the second plane <NUM>, the third plane <NUM> is not necessarily defined by any particular object within the implantable medical device <NUM> but instead is introduced to provide the relationships of components. The third plane <NUM> is parallel to the first plane <NUM> while passing through the centerline of the first lead bore <NUM> and the second lead bore <NUM>. For some embodiments the third plane <NUM> may provide further constraints such as by being parallel to the lower feedthrough wall <NUM>, being defined by a surface of the lower feedthrough wall <NUM>, and/or being coplanar with a surface of the lower feedthrough wall <NUM> while bisecting the lower feedthrough wall <NUM>. In still other embodiments, the third plane <NUM> only passes through the centerline of either the first lead bore <NUM> or the second lead bore <NUM> because the centerlines of the two lead bores are offset somewhat from one another. In this case, a fourth plane (not shown) passes through the centerline of the other one of the first or second lead bore and is parallel to the first plane <NUM> and third plane <NUM>. For some embodiments the fourth plane may provide further constraints such as by being parallel to the lower feedthrough wall <NUM>, being defined by a surface of the lower feedthrough wall <NUM>, and/or being coplanar with a surface of the lower feedthrough wall <NUM> while bisecting the lower feedthrough wall <NUM>.

<FIG> also shows geometric relationships that may be utilized by various embodiments of the implantable medical device <NUM> including the example as shown in <FIG> to position the header-related structures including the lead bore adjacent to the primary device housing <NUM> and related components. <FIG> shows the first plane <NUM> and the third plane <NUM>' as discussed above in <FIG>, including the third plane <NUM>' intersecting the lead bore <NUM>. In this specific example, the third plane <NUM>' represents a plane established by the lower feedthrough wall <NUM>. A plane <NUM> defined by the outer surface of the exterior wall panel <NUM> is the right-most plane. To the left of plane <NUM> resides the first plane <NUM> of the circuit board <NUM> and then a plane <NUM> defined by the outer surface of the upper housing wall <NUM>. To the left of plane <NUM> resides the third plane <NUM>' and then a plane <NUM> established by the outer surface of the exterior wall panels <NUM>, <NUM>. Any combination or all of these planes of <FIG> may be parallel to each other.

From <FIG> and <FIG>, various observations can be made. For instance, it can be seen that the lead bore <NUM> is positioned between the circuit board <NUM> and the wall established by panels <NUM>, <NUM>. It can be seen that the circuit board <NUM> is positioned between the first lead bore <NUM> and the wall established by panel <NUM>. It can further be seen that the lower feedthrough wall <NUM> is positioned between the circuit board <NUM> and the exterior wall established by the panels <NUM>, <NUM> such that this exterior wall is adjacent lower feedthrough wall <NUM>. It can further be seen that the feedthrough conductors are present between the lower feedthrough wall <NUM> and the wall established by the panels <NUM>, <NUM>.

In one example, an implantable medical device comprises a housing comprising an exterior wall; a circuit board within the housing, the circuit board including circuitry; a header affixed to the housing and bordering the exterior wall such that a portion of the header lies directly adjacent to a portion of the exterior wall, the header providing a first lead bore having a longitudinal centerline, wherein the circuit board is positioned between the exterior wall and the first lead bore; and an electrical connector that is positioned within the first lead bore and that is electrically coupled to the circuitry.

In this example, the circuit board may have a side providing a largest surface area of the circuit board, the side defining a first plane, the first lead bore being positioned such that a second plane is parallel to the longitudinal centerline of the first lead bore, intersects the first lead bore, intersects the circuit board, and is perpendicular to the first plane. The header may provide a second lead bore having a longitudinal centerline, and wherein the second plane is parallel to the longitudinal centerline of the second lead bore. A third plane may be parallel to the first plane and passes through the centerline of the first lead bore and through the centerline of the second lead bore. The header may comprise a first wall that is parallel to the first plane and the housing comprises a second wall that is parallel to the first plane, wherein the first lead bore is positioned between the circuit board and the first wall and the circuit board is positioned between the first lead bore and the second wall. The housing may comprise a feedthrough wall that has a feedthrough aperture and the housing comprises an exterior wall adjacent the feedthrough wall such that the feedthrough wall is positioned between the circuit board and the exterior wall.

In this example, the implantable medical device may further comprise a feedthrough positioned within the feedthrough aperture of the feedthrough wall; and a feedthrough conductor electrically coupled to the circuitry. The feedthrough conductor may extend from the side of the circuit board and passing through the feedthrough, the feedthrough conductor having a bend on a side of the feedthrough opposite the circuit board, the feedthrough conductor extending from the bend toward the electrical connector and between the feedthrough wall and the exterior wall, the feedthrough conductor being electrically coupled to the electrical connector. The housing may comprise threaded holes, the implantable medical device further comprising screws passing through the circuit board and engaging the threaded holes. The screws and the housing may provide the threaded holes are a same material. The circuit board may include a ground plane that is electrically coupled to a conductive portion of the circuit board. The housing may include a screw hole, and the implantable medical device may further comprise a screw that affixes the circuit board to the housing and electrically couples the ground plane to the housing by contacting the conductive portion while being present in the screw hole of the housing.

Claim 1:
An implantable neurostimulator, comprising:
a housing (<NUM>);
a header (<NUM>) affixed to the housing (<NUM>), the header (<NUM>) providing a first lead bore (<NUM>) having a longitudinal centerline (<NUM>);
an electrical connector (<NUM>) positioned within the first lead bore (<NUM>);
a circuit board (<NUM>) within the housing, the circuit board (<NUM>) including circuitry that is electrically coupled to the electrical connector (<NUM>), the circuit board (<NUM>) having a side providing a largest surface area of the circuit board (<NUM>), the side defining a first plane (<NUM>), the first lead bore (<NUM>) being positioned such that a second plane (<NUM>) is parallel to the longitudinal centerline (<NUM>) of the first lead bore (<NUM>), intersects the first lead bore (<NUM>), intersects the circuit board (<NUM>), and is perpendicular to the first plane (<NUM>),
wherein the housing comprises a feedthrough wall (<NUM>) that has a feedthrough aperture and the housing comprises an exterior wall adjacent the feedthrough wall such that the feedthrough wall (<NUM>) is positioned between the circuit board and the exterior wall, the implantable neurostimulator further comprising:
a feedthrough (<NUM>) positioned within the feedthrough aperture of the feedthrough wall (<NUM>); and
a feedthrough conductor (<NUM>) electrically coupled to the circuitry, the feedthrough conductor (<NUM>) extending from the side of the circuit board and passing through the feedthrough, the feedthrough conductor having a bend on a side of the feedthrough opposite the circuit board, the feedthrough conductor extending from the bend toward the electrical connector and between the feedthrough wall (<NUM>) and the exterior wall, the feedthrough conductors being electrically coupled to the electrical connector (<NUM>).