Patent Publication Number: US-2022233863-A1

Title: Cuff electrode

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/485,954, filed Aug. 14, 2019, which is a 35 U.S.C. § 371 National Phase application, and claims priority to, PCT Application No. PCT/US18/46100, filed Aug. 9, 2018, which claims the benefit of U.S. Provisional Patent Application No. 62/544,140, filed Aug. 11, 2017, all of which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     Treating sleep disordered breathing has led to improved sleep quality for some patients. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view schematically representing an example cuff electrode. 
         FIG. 2  is a sectional view schematically representing the example cuff electrode of  FIG. 1  as taken along lines  2 - 2 . 
         FIG. 3  is a sectional view schematically representing the example cuff electrode  FIG. 1  as taken along lines  3 - 3 . 
         FIG. 4  is a diagram including an isometric view schematically representing different portions of an example cuff electrode. 
         FIG. 5A  is a diagram including an isometric view schematically representing an example device including different portions of a cuff body and an electrode pattern of the cuff electrode of  FIG. 4 . 
         FIG. 5B  is a diagram including a sectional view schematically representing relative arc lengths of circumferential portions of an example cuff body. 
         FIG. 6A  is a diagram including a sectional view schematically representing an example cuff electrode relative to nerve groups within a nerve. 
         FIG. 6B  is diagram including a sectional view as taken along lines  6 B- 6 B of  FIG. 6A  and schematically representing an electrode array of an example cuff electrode. 
         FIGS. 7A-7K  is a series of diagrams, each schematically representing different example electrical stimulation vectors and/or example methods. 
         FIG. 8A  is an isometric view schematically representing an example cuff electrode. 
         FIG. 8B  is a diagram schematically representing an example electrode pattern of the cuff electrode of  FIG. 8A . 
         FIG. 9  is a sectional view schematically representing the example cuff electrode of  FIG. 8A , as taken along lines  9 - 9 . 
         FIG. 10  is an isometric view schematically representing an example cuff electrode. 
         FIG. 11  is a diagram schematically representing an example electrode pattern of the cuff electrode of  FIG. 10 . 
         FIG. 12  is an isometric view schematically representing an example cuff electrode. 
         FIG. 13A  is a diagram schematically representing an example electrode pattern of the cuff electrode of  FIG. 12 . 
         FIG. 13B  is a diagram schematically representing an example electrode pattern of the cuff electrode of  FIG. 12 . 
         FIG. 14A  is a sectional view schematically representing an example cuff electrode including some electrodes partially housed within inwardly-oriented protrusions of a nerve-contact surface. 
         FIG. 14B  is a sectional view schematically representing an example cuff electrode including some electrodes partially housed within inwardly-oriented protrusions of a nerve-contact surface. 
         FIG. 15A  is a diagram including a plan view schematically representing a nerve-contact surface of an example cuff electrode and example electrode pattern relative to some circular-shaped inwardly-oriented protrusions of the nerve-contact surface. 
         FIG. 15B  is a diagram including a plan view schematically representing a nerve-contact surface of an example cuff electrode and example electrode pattern relative to some elongate inwardly-oriented protrusions of the nerve-contact surface. 
         FIG. 15C  is a diagram including a plan view schematically representing a nerve-contact surface of an example cuff electrode and example electrode pattern relative to some circular-shaped inwardly-oriented protrusions of the nerve-contact surface. 
         FIG. 15D  is a diagram including a plan view schematically representing a nerve-contact surface of an example cuff electrode and example electrode pattern relative to some elongate inwardly-oriented protrusions of the nerve-contact surface. 
         FIG. 16  is a diagram including an isometric view schematically representing different portions of an example cuff body. 
         FIG. 17A  is a diagram including a plan view schematically representing a nerve-contact surface of an example cuff electrode and example electrode pattern relative to some circular-shaped inwardly-oriented protrusions of the nerve-contact surface. 
         FIG. 17B  is a diagram including a plan view schematically representing a nerve-contact surface of an example cuff electrode and example electrode pattern relative to some circular-shaped inwardly-oriented protrusions of the nerve-contact surface. 
         FIG. 17C  is a diagram including a plan view schematically representing a nerve-contact surface of an example cuff electrode and example electrode pattern relative to some elongate inwardly-oriented protrusions of a nerve-contact surface. 
         FIG. 18A  is a sectional view schematically representing an example cuff electrode including some electrodes partially housed within outwardly-oriented protrusions. 
         FIG. 18B  is a sectional view schematically representing an example cuff electrode including some electrodes partially housed within outwardly-oriented protrusions. 
         FIG. 19A  is block diagram schematically representing an example fully implantable neurostimulation system including a pulse generator, lead, and cuff electrode. 
         FIG. 19B  is block diagram schematically representing an example neurostimulation system including a pulse generator and leadless cuff electrode. 
         FIG. 20  is a block diagram schematically representing an example control portion. 
         FIG. 21  is a block diagram schematically representing an example user interface. 
         FIGS. 22A-22U  are each a flow diagram, or a portion of a flow diagram, schematically representing an example method. 
         FIG. 23  is a diagram schematically representing an example nerve branch configuration at which an example cuff electrode may be mounted. 
         FIG. 24  is a diagram schematically representing an example cuff electrode including a distal extension engaged relative to an example nerve branch configuration. 
         FIG. 25  is a diagram schematically representing an example cuff electrode including a distal extension. 
         FIG. 26  is a diagram schematically representing an example cuff electrode including a distal extension. 
         FIG. 27  is a diagram schematically representing an example cuff electrode including a distal extension. 
         FIGS. 28A-28E  are each a flow diagram, or a portion of a flow diagram, schematically representing an example method. 
         FIGS. 29A-29B  are each a flow diagram, or a portion of a flow diagram, schematically representing an example method. 
     
    
    
     DETAILED DESCRIPTION 
     In the following Detailed Description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples of the present disclosure which may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., may be used with reference to the orientation of the Figure(s) being described. Because components of at least some examples of the present disclosure can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. 
     In at least some examples, a cuff electrode includes an electrode array suited to selective stimulation profiles which may enhance electrical stimulation of a nerve. In some examples, the nerve comprises an airway-patency-related nerve to treat sleep disordered breathing behavior. In some examples, the airway-patency-related nerve comprises a nerve which innervates a tongue muscle. In some examples, the nerve comprises the hypoglossal nerve. Accordingly, in at least some instances, the airway-patency-related nerve may sometimes be referred to as an upper-airway-patency-related nerve. 
     In some examples, the cuff electrode comprises a cuff body supporting at least one array of first electrodes extending axially along a length of the cuff body in a first orientation. In some examples, the cuff electrode includes at least one array of second electrodes extending in a second orientation generally perpendicular to the first orientation. The second orientation may sometimes be referred to as a circumferential orientation while the first orientation may sometimes be referred to as an axial orientation. In some examples, one of the first electrodes of the axially-extending array functions as one of the second electrodes of the circumferentially-extending array. 
     In some examples, other than the array of axially-extending first electrodes, the cuff electrode omits any other electrodes (or other electrically conductive materials) in the portions of the cuff body which extend proximally and extend distally relative to the array of circumferentially-extending second electrodes. Via this arrangement, such electrically-conductive-free portions of the cuff body may act as electrical insulative portions to minimize stimulation toward non-targeted nerve branches and surrounding non-nerve tissues. In addition, as part of the overall cuff body, these electrically-conductive-free portions act to mechanically secure the electrodes relative to the nerve. Moreover, via this arrangement, the cuff body retains high flexibility in its distal and proximal portions, thereby contributing to maneuverability of the cuff electrode during implantation. 
     In various other examples, a cuff electrode comprises additional electrodes and/or electrode arrays to provide more combinations of selectable electrodes. 
     These examples, and additional examples, are described in more detail in association with at least  FIGS. 1-29B . 
       FIG. 1  is an isometric view schematically representing a cuff electrode  100 , according to one example of the present disclosure. As shown in  FIG. 1 , the cuff electrode  100  comprises a cuff body  101  including a first arm  134  and a second arm  150 , which together form a re-closable lumen  140 . In some examples, an end  135  of the first arm  134  and an end  151  of the second arm  150  are releasably engageable relative to each other to at least partially define the re-closable lumen  140 . It will be understood that in some examples, the point of releasable engagement  109  may be located at other positions about the circumference of the re-closable lumen  140 , with the respective arms  134 ,  150  having different relative lengths (than shown in  FIG. 1 ) to implement the particular location of releasable engagement of the ends of the respective arms  134 ,  150 . It will be understood that for illustrative clarity  FIG. 1  depicts a small gap at the point of releasable engagement  109 , even though in at least some examples the ends  135 ,  151  may be touching each other. 
     In some examples, cuff body  101  comprises a third arm  160  which overlaps second arm  150  and first arm  134 , as further described later in association with at least  FIG. 2 . 
     As shown in  FIG. 1 , in some examples, cuff electrode  100  comprises a first array  102  of spaced apart electrodes  103 A,  103 B,  103 C extending axially along a length of the cuff body  101  and a second array  112  of electrodes  113 A- 1130 , which extends circumferentially about a nerve-contact surface  143  of lumen  140 . In some examples, the electrodes  103 A,  103 B,  103 C of the example first array  102  may sometimes be referred to as first electrodes. In some examples, the electrodes  113 A,  113 B,  113 C of the example second array  112  may sometimes be referred to as second electrodes. 
     In some examples, the electrodes  113 A,  113 B,  113 C extend in the same cross-sectional plane (e.g. a single cross-sectional plane), as further shown later in at least  FIGS. 2, 5B, 6A , etc. The respective electrodes  103 A- 1030 ,  113 A- 113 C are at least partially exposed on nerve-contact surface  143  of lumen  140 , such as shown in  FIG. 1  and later shown in at least  FIGS. 6A-6B  and/or  FIG. 9 . In some examples, electrode  103 B of first array  102  functions as (i.e. is the same physical element) electrode  113 B in the second array  112 . In some examples, the various electrodes have generally the same size and/or shape. In some examples, at least some of various electrodes may be differently sized and/or differently shaped than other electrodes. 
     In some examples, electrode  113 A is supported on second arm  150  while electrode  113 C is supported on first arm  134  while electrodes  103 A- 103 C are supported on a proximal portion of first arm  134  and/or a top portion of base  120 . The base  120  supports and/or at least partially defines a junction of the proximal portions of the respective first and second arms  134 ,  150 . While not shown for illustrative clarity, base  120  may house electrically conductive elements which extend from lead  82  and at least partially through a length (e.g. L 1 ) of the base  120  for connection to electrodes  103 A- 1030 ,  113 A- 113 C. In some instances, base  120  also may sometimes be referred to as a spine. 
     In some examples, an electrode of the cuff electrode  100  may sometimes be referred to as an electrode contact because each electrode includes an electrically conductive contact surface intended to engage tissue, such as an outer surface of a nerve, through which electrical stimulation is to be applied. 
     Accordingly, with reference to at least  FIG. 1 , in some examples the inner electrodes  113 A,  113 B ( 103 B),  113 C of the circumferentially-oriented array  112  comprises three independently programmable electrodes while the outer electrodes  103 A,  103 C are electrically common with each other, such that the cuff electrode  100  has four independently programmable functional electrodes. In some examples, via this arrangement the outer electrodes  103 A,  103 C may be operated as anodes such that cuff electrode  100  provides a guarded cathode arrangement with the inner axial electrodes  113 A,  113 B ( 103 B),  113 C selectively operable as cathodes. 
     In some examples, the three axially arranged electrodes (e.g. electrode  103 A, electrode  103 C, and at least one of  113 A,  1138 ,  113 C electrodes) may implement a guarded bipolar configuration in which positive electrodes on the ends of the cuff hyperpolarize the nerve to prevent stimulation of non-target tissues. In some examples, the reference to positive electrodes and negative electrodes may refer to the first phase of biphasic stimulation, e.g. the phase of stimulation intended to depolarize the target nerve. 
     In some examples, having three inner electrodes  113 A,  113 B,  113 C which are equally spaced apart in a circumferential orientation may enhance selective stimulation of particular targeted and non-targeted branches of a nerve bundle. For instance, via such selective stimulation one may exclude (e.g. non-target) one of the branches of a target nerve (e.g. hypoglossal nerve). For instance, it may be beneficial in some examples to not stimulate a branch of the hypoglossal nerve, which would cause retraction of the tongue, with such nerve branches being referred to herein as a retractor nerve branch. 
     For example, supposing just two circumferentially oriented electrodes were equally spaced apart (e.g. 180 degrees apart) and a non-target branch were located at 90 degree angle relative to each of the respective pair of electrodes, then it may sometimes be difficult to apply a signal with sufficient strength to capture the target nerve branches to achieve the desired muscle response (e.g. tongue protrusion) while still excluding the non-target nerve branches (e.g. tongue retractors). 
     For example, in some instances a retractor nerve branch may split off from the main nerve bundle early such that the retractor nerve is external to the remaining nerve bundle at the point at which the cuff body/electrode  100  is releasably engaged about the main nerve bundle. In some instances a retractor nerve branch remains within the main nerve bundle but is in close proximity to one of the inner electrodes  113 A,  1138 ,  113 C such that non-activation of the particular electrode  113 A,  1138 ,  113 C closest to the retractor nerve branch may serve to exclude the retractor nerve branch from stimulation, while activation of the remaining two electrodes (of the three electrodes  113 A,  113 B,  113 C) are sufficient to depolarize the protrusor-related branches of the main nerve bundle. 
     In some examples, in some instances in which a targeted nerve branch may be located at an intermediate position between two of the circumferentially spaced apart electrodes, an adequate depolarization of the target nerve branch may be implemented via applying a high strength signal at one electrode. In some examples, application of a low or moderate strength signal at the remaining two electrodes may contribute to depolarization of the target nerve branches, as desired. Accordingly, regardless of the particular position of the main target nerve branches within the main nerve bundle, the availability of three electrodes  113 A,  113 B,  113 C (which are equally spaced in the circumferential orientation) may ensure some combination of activation of at least some of such electrodes to achieve adequate depolarization of target nerve branches. 
     In some such examples, as noted above and throughout examples of the present disclosure, such an electrode configuration may also serve to exclude non-target nerve branches from stimulation in some instances. Moreover, in some examples, via at least some of the electrodes  113 A,  113 B,  113 C, hyperpolarization may be implemented to inhibit stimulation of some nerve branches (e.g. retractor nerve branches) or other nerve branches exhibiting a negative response. 
     In some examples, cuff electrode  100  may be implemented having at least some of substantially the same features and attributes as one of the cuff electrodes described in Bonde et al. U.S. Pat. No. 9,227,053, “Self-Expanding Electrode Cuff”, issued on Jan. 5, 2016, and/or in Bonde et al. U.S. Pat. No. 8,340,785, “Self-Expanding Electrode Cuff”, issued on Dec. 25, 2012, both of which are herein incorporated by reference. 
     In some examples, the array of first electrodes  103 A,  103 B,  103 C and the array of second electrodes  113 A,  113 B (same as  103 B),  113 C together exclusively define all the electrodes supported on the cuff body. In some examples, the array of first electrodes  103 A,  103 B,  103 C and the array of second electrodes  113 A,  113 B (same as  103 B),  113 C together exclusively define all the electrodes supported on an implantable medical device, which includes the cuff body. In some examples, this implantable medical device includes a cuff electrode and an implantable pulse generator. In some examples, this implantable medical device includes a cuff electrode, an implantable pulse generator, and lead extending between the cuff electrode and implantable pulse generator. In some examples, this implantable medical device includes a cuff electrode, an implantable pulse generator, a lead extending between the cuff electrode and implantable pulse generator, and a separate respiration sensor/lead. 
       FIG. 2  is a sectional view schematically representing the cuff electrode of  FIG. 1  as taken along lines  2 - 2 , according to one example of the present disclosure. In some examples, the cuff electrode  100  in  FIG. 2  comprises at least some of substantially the same features and attributes as cuff electrode  100  in  FIG. 1 , except for further depicting the third arm  160  in addition to the respective first and second arms  134 ,  150 . As shown in  FIG. 2 , the distal portion  137  of the first arm  134  is bendable (per directional arrow B) and the second arm  150  is bendable (per directional arrow D) to open cuff body  101  to enclose a nerve within lumen  140 . In addition, in  FIG. 2  the third arm  160  is shown in an already-bent position (per directional arrow E) to permit access to lumen  140  and to permit selective movement of the first and second arms  134 ,  150 . It will be understood that, after manipulation to open the cuff electrode  100  for mounting a nerve, each of the respective arms  134 ,  150 ,  160  are biased to return to their “closed” position forming the re-closable lumen  140 . 
     As shown in  FIG. 2  and as further described in association with at least  FIGS. 4-5B , in some examples the cuff body  101  may be understood as having different portions with boundaries between the respective portions represented via dashed lines. It will be understood that in at least some examples the dashed lines shown in the Figures do not represent actual seams or discontinuities in the cuff body. It will be further understood that other conventions for allocating different portions of cuff body  101  may be adopted. 
     For instance, in some examples the cuff body  101  may be viewed as having different portions along a circumferential orientation (line C), which is generally perpendicular to an axial orientation (line A in  FIGS. 1, 3 ) of the cuff body  101 . In some examples, the cuff body  101  may be viewed as having an inner circumferential (IC) portion  182  and two outer circumferential portions  184 A,  184 B with the respective portions  182 ,  184 A,  184 B extending throughout the entire length of the cuff body  101 . Boundaries between the respective inner circumferential (IC) portion  182  and the outer circumferential (OC) portions  184 A,  184 B are represented via dashed lines  187 A,  187 B. The inner circumferential and outer circumferential designations will be further described in association with at least  FIGS. 5A-5B . 
     In some examples, the inner circumferential portion  182  corresponds to a location of the nerve-contact surface  143  at which the electrodes  103 A,  103 B,  103 C are located. In one aspect, the inner circumferential portion  182  provides for the electrode  113 B (i.e.  103 B) to have an intermediate position relative to the respective outer electrodes  113 A,  113 C. 
       FIG. 3  is a sectional view schematically representing a cuff electrode as taken along lines  3 - 3  of  FIG. 1 , according to one example of the present disclosure. As shown in  FIG. 3 , in some examples the cuff body  101  may be viewed as having different portions extending along an axial orientation, which is generally parallel to a longitudinal axis (line A in  FIG. 1 ) of the cuff body  101 . In some examples, the different portions may be referred to as an inner axial portion  202  and two outer axial portions  204 A,  204 B with each axial portion including one of the electrodes  103 A,  103 B,  103 C. As further shown at least partially in  FIG. 3 , the inner axial portion  202  also includes the electrodes  113 A,  113 B,  113 C of the second array  112 . 
     As further shown in  FIG. 3 , in some examples an electrically conductive element  170  extends through a length of a base  120  of the cuff body  101  and is electrically coupled relative to each of the respective electrodes  103 A,  103 B,  103 C. In some examples, the electrically conductive element  170  may take the form of coil, and includes several electrically independent conductive strands  171  such that each electrode  103 A,  103 B,  103 C is independently programmable/controllable. 
     While not shown in  FIG. 3  for illustrative simplicity, it will be understood that in some examples additional electrically independent conductive elements (e.g. wires) extend from a portion of the electrically conductive element  170  and are electrically connected to the electrodes  113 A,  113 B  113 C of the second array  112  in the inner axial portion  202  of the cuff body  101  such that each electrode  113 A,  113 B (same as  103 B),  113 C is also independently programmable/controllable. 
     In some examples, the additional electrically independent conductive elements may promote flexibility of the overall cuff structure and may withstand expected flexing of the cuff body. In some such examples, the additional electrically independent conductive elements extending through at least a portion of the cuff body may comprise at least some undulating portions and/or otherwise designed to flex. 
     However, in at least some examples, the “additional” electrically independent conductive elements extend circumferentially within the inner axial portion  202  of the cuff body  101 . Moreover, in some examples these “additional” electrically independent conductive elements do not extend circumferentially within the outer axial portions  204 A,  204 B of the cuff body  101 , as further described later in association with at least  FIGS. 4, 5A-5B . 
       FIGS. 4-5A  provide further illustrations of the respective different portions of cuff body  101 .  FIG. 4  is a diagram including an isometric view schematically representing different portions of a cuff electrode  200  including a cuff body  201 , according to one example of the present disclosure. Portions of the cuff body  201  are akin to the cuff body  101  ( FIG. 2 ). In one aspect, the diagram in  FIG. 4  expands on designations associated with the schematic representation of the inner and outer circumferential portions  184 A,  184 B in  FIG. 2  and of the inner and outer axial portions in the sectional view of  FIG. 3 . In some examples, the point of releasable engagement  109  is used as a reference point to define a boundary between at least some of the different portions of the cuff body  101 ,  201 . However, in some examples other reference points may be used. 
       FIG. 5A  is a plan view schematically representing a nerve-contact surface of the cuff electrode  200  of  FIG. 4  with the cuff body  201  fully opened and laid out flat for illustrative purposes. 
       FIG. 5A  depicts different portions of the cuff body  101  with portions  252 A,  252 B,  252 C corresponding to a first outer axial (OA) portion  204 A and with portions  254 A,  254 B,  254 C corresponding to a second outer axial (OA) portion  204 B. Moreover, portions  250 A,  250 B,  250 C in  FIG. 5A  correspond to inner axial (IA) portion  202 . Meanwhile, portions  252 B,  250 B,  254 B in  FIGS. 4-5A  correspond to inner circumferential (IC) portion  182  in  FIG. 2 . Portions  252 A,  250 A,  254 A in  FIGS. 4-5A  correspond to a first outer circumferential (OC) portion  184 A and portions  252 C,  250 C,  254 C in  FIGS. 4-5A  correspond to a second outer circumferential (OC) portion  184 B. With this in mind, in viewing  FIG. 5A  it can be seen that any given portion (e.g.  252 C) includes both an axial and circumferential designation (e.g. OA and OC). 
     In some examples, the outer axial portions (e.g.  252 A,  252 C,  254 A,  254 C) omit any electrically conductive elements, such as electrodes and/or electrically conductive elements (e.g. wires) extending to/from an electrode in a different portion of the cuff body  201 . Stated differently, any wires which extend in or through the inner axial, outer circumferential portions  250 A,  250 C of the cuff body  101 ,  201  do not pass through the outer axial, outer circumferential portions  252 A,  252 C,  254 C,  254 C of the cuff body  101 ,  201 . In other words, the outer axial, outer circumferential portions of the cuff body  101 ,  201  are free from any electrically conductive elements (e.g. wires, traces, etc.). In this way, these respective portions (e.g.  252 A,  252 C,  254 A,  254 C) act as electrically insulative portions, which in some examples, may contribute to selective stimulation of a target nerve portion by minimizing inadvertent stimulation of non-targeted surrounding tissues 
     In addition, the omission of electrodes and/or conductive elements (e.g. wires) in the proximal outer axial portions  252 A,  252 C and the distal outer axial portions  254 A,  254 C of the cuff electrode  100  may enhance flexibility of the respective distal and proximal ends of the cuff body  101 . In some examples, this enhanced flexibility may permit easier placement of the cuff electrode  100  relative to the nerve and/or may enhance gentler contact with the nerve. In some examples, the effect of these flexibility enhancements may be greater when the cuff electrode  101  is placed on more distal portions of the target nerve, such as a hypoglossal nerve. In some such examples, the proximal outer axial portions (e.g.  252 A,  252 C) and the distal outer axial portions (e.g.  254 A,  254 C) may sometimes be referred to as being more flexible than inner axial portion (e.g.  250 A,  250 B,  250 C) and/or may sometimes be referred to as being electrically-conductive-free portions. In some such examples, the proximal outer axial portions (e.g.  252 A,  252 C) and the distal outer axial portions (e.g.  254 A,  254 C) are substantially more flexible, such as 25%, 50%, 75% more flexible, than the inner axial portions (e.g.  252 A,  252 C). In some such examples, the term substantially more flexible may correspond to being 2×, 3×, 4× more flexible. 
     While the cuff body  101  is made of a polymeric material which is generally electrically non-conductive, in some examples, the proximal outer axial portion  252 C and distal outer axial portion  254 C further includes additive electrically insulative material to further protect non-targeted surrounding tissues from unintended stimulation. 
     By providing this arrangement of just a single array of circumferentially-oriented electrodes  113 A,  113 B,  113 C (in addition to the axially-oriented array of first electrodes  103 A- 1030 ) instead of a fully cylindrical array (e.g. 3×3, 4×4, etc.), fewer wires extend through/within the lead body  82  up to and through the length of the cuff body  101 , which in turn provides for a highly flexible lead suited to the highly mobile neck structure. By providing a lead body  82  with relatively high flexibility as it extends through/within the neck region (upon implantation), patient comfort and longevity of the lead body  82  may be enhanced because the lead body  82  is able to flex well with the many different positions and frequency of movement of the neck region. 
     In some examples, as shown in at least  FIG. 3 , D 5  represents the axial length of the electrically-conductive-free portions (e.g.  252 C,  254 C, etc.) of cuff body from the inner axial, circumferentially-oriented electrodes  113 A,  113 B,  113 C to an end  107  of the cuff body  101 . In some examples, this axial length (D 5 ) is substantially greater than a width (W 1 ) of the electrodes  113 A,  113 B,  113 C. In some examples, the axial length D 5  is at least 3 times the width W 1 . In some examples, the axial length D 5  is at least 4 times the width W 1 . 
     In addition, once the cuff electrode  100  is implanted at a desired location along a length of the target nerve (e.g. hypoglossal nerve), in some examples the opposite ends  107 ,  108  of the cuff body  101 ,  201  may sometimes lie in close proximity to other nerve branches extending off the target nerve. By omitting additional electrodes in the proximal outer axial portion ( 252 A,  252 C) and the distal outer axial portion ( 254 A,  254 C) of the cuff body  201 , selective stimulation may be confined primarily in an area interior to the opposite ends  107 ,  108  of the cuff body  201 , which in turn may minimize incidental stimulation of the non-target nerve branches and/or other surrounding non-nerve tissues. 
     As further shown in  FIG. 5A , the various different portions of cuff body  201  are depicted as having a generally uniform width (W 2 , W 3 , W 4 ) and generally uniform length (L 2 , L 3 , L 4 ). However, in some examples the widths and/or lengths of the various different portions may be non-uniform, such that W 3  is greater than W 2 , W 4  is greater than W 2 , etc. as some non-limiting examples. Moreover, while  FIG. 4  depicts the thickness of the wall of the cuff body  101  as having a generally uniform thickness for illustrative simplicity, it will be understood that the thickness of a given portion (e.g.  252 A) may vary along its length and/or width in some examples and that thickness of one portion (e.g.  252 A) need not necessarily match a thickness of another portion (e.g.  254 C). 
     As shown in the sectional view of  FIG. 5B , in some examples, according to the circumferential orientation the three respective outer and inner circumferential portions  184 A,  184 B,  182  have generally equal arc lengths (AL 1 , AL 2 , AL 3 ), such that each extends about 120 degrees arc of a 360 degree circumference. It will be understood that the reference numerals AL 1 , AL 2 , AL 3  in  FIG. 5B  correspond to the designators W 2 , W 3 , W 4  in  FIG. 5A . In some examples, the inner circumferential portion  182  extends less than a 120 degree arc, such as a 100 degree arc. In some examples, a first outer circumferential portion  184 A (e.g. OC portions  252 A,  250 A,  254 A) has a circumferential arc length (AL 1 ; W 2 ) that is substantially the same as a circumferential arc length (AL 3 ; W 4 ) of the second outer circumferential portion  184 B (e.g. OC portions  252 C,  250 C,  254 C). 
     However, in some examples, the first outer circumferential portion  184 A (e.g. OC portions  252 A,  250 A,  254 A) has a circumferential arc length (AL 1 ; W 2 ) that is different from the circumferential arc length (AL 3 ; W 4 ) of the second outer circumferential portion  184 B (e.g. OC portions  252 C,  250 C,  254 C). In some examples, the first outer circumferential portion  184 A (e.g. OC portions  252 A,  250 A,  254 A) has a circumferential arc length (AL 1 ; W 2 ) that is substantially less than a circumferential arc length (AL 3 ; W 4 ) of the second outer circumferential portion  184 B (e.g. OC portions  252 C,  250 C,  254 C) as shown in  FIG. 4 . 
     In some examples associated with at least  FIGS. 1-5B , a size and/or shape of each of the inner axial portion  202  (portions  250 A,  250 B,  250 C) of the cuff body  201  may be at least partially characterized by having no more than one electrode (e.g.  113 A,  113 B (also known as  103 B),  113 C) and a size and/or shape of each portion  252 B,  254 B (inner circumferential IC, outer axial OA) of the cuff body  201  may be characterized as having no more than one electrode (e.g.  103 A,  103 C, respectively). 
     However, as later described in association with at least  FIGS. 14A, 14B, 18A, 18B , in some examples a portion  250 A (outer circumferential OC, inner axial IA) of the cuff body  201  omits an electrode (e.g.  113 A) while a portion  250 C (outer circumferential OC, inner axial IA) of the cuff body  201  includes two electrodes (e.g.  113 A,  113 C). 
     While cuff electrode  100  is shown in  FIG. 1  as extending from a lead body  82 , it will be understood that in some examples the cuff electrode  100  may comprise a leadless cuff electrode  1100 , as later shown in  FIG. 19B . Accordingly, in some examples, the leadless cuff electrode  1100  may comprise an antenna and/or circuitry for wirelessly communicating with a control portion ( FIG. 20 ) and/or a pulse generator  1110  located external to the patient&#39;s body ( FIG. 19B ) and/or located elsewhere in the patient&#39;s body ( FIG. 19A ). In some examples, the antenna and/or circuitry is housed within the base  120  of the cuff body of cuff electrode  1100 . 
     Accordingly, with reference to at least  FIGS. 1-5B , in some examples the inner electrodes  113 A,  113 B ( 103 B),  113 C of the circumferentially-oriented array comprises three independently programmable electrodes while the outer electrodes  103 A,  103 C are electrically common with each other, such that the cuff electrode  100 ,  200  has four independently programmable functional electrodes. In some examples, via this arrangement the outer electrodes  103 A,  103 C may be operated as anodes such that cuff electrode  100  provides a guarded cathode arrangement with the inner axial electrodes  113 A,  113 B ( 103 B),  113 C selectively operable as cathodes. 
     In some examples, as later shown in  FIG. 19A-19B , the cuff electrode  100 ,  200  is associated with an implantable pulse generator (IPG)  1110  having an external conductive case, which may selectively act as an electrode in cooperation with the functional electrodes of cuff electrode  100 . 
     Via the arrangement of the axial array of electrodes  103 A,  103 C, and the circumferentially-oriented array of electrodes  113 A,  113 B (same as  103 B),  113 C of cuff electrode  100 , effective selective stimulation may be achieved without unduly complicating the associated programming to do so. Moreover, a high degree of selectivity in stimulating various nerve fiber groups may be achieved with a relatively small number of electrodes. 
     In some examples, the particular arrangement of electrodes  113 A- 1130 ,  103 A- 1030  depicted in at least  FIGS. 1-5B  may be implemented in a cuff body having a different configuration of arms than the particular arrangement of arms of cuff body  101 ,  201  shown in  FIGS. 1-5B . 
       FIG. 6A  is a sectional view schematically representing a cuff electrode  270  engaged about a nerve  261 , according to one example of the present disclosure. In at least some examples,  FIG. 6A  also may be viewed as schematically representing a method of neurostimulation and/or therapy to treat sleep disordered breathing, such as but not limited to obstructive sleep apnea. In some examples, cuff electrode  270  comprises at least some of substantially the same features and attributes of cuff electrodes  100 ,  200  as described in association with at least  FIGS. 1-5B . This sectional view generally corresponds to the sectional view of  FIG. 2  as taken through inner axial portions  250 A,  250 B,  250 C of cuff body  101 ,  201 . Among other features,  FIG. 6A  illustrates that, in at least some examples, the circumferentially-oriented array of electrodes  113 A,  113 B,  113 C are equally spaced apart about circumference of nerve-contact surface  143  of cuff body  101 ,  271 . It will be understood that a nerve-contact surface  143  of cuff electrode  270  is in releasable contact against an outer surface  263  of nerve  261  with  FIG. 6A  and that the minor spacing shown between the nerve-contact surface  143  and outer surface  263  of nerve  261  are provided for illustrative clarity. 
     As shown in  FIG. 6A , the nerve  261  comprises several nerve fiber groups  262 A- 262 D, with the exact number (e.g. 3, 4) of nerve fiber groups varying from nerve-to-nerve and dependent on a location along the nerve. In some instances, more nerve fiber groups are present in more proximal portions of a nerve and fewer nerve fiber groups are present in more distal portions of a nerve pathway. In general terms, the nerve fiber groups  262 A- 262 D may be considered as being arranged in a generally circumferential pattern. However, the depiction in  FIGS. 6A-6B  provides just one example pattern with it being further understood that the various nerve fiber groups may have different diameters from each other and/or may have positions within the nerve casing which vary from the positions shown in  FIG. 6A . 
     In attempting to electrically stimulate the nerve  261  as a whole, each of the nerve fiber groups may exhibit different responses than each other. In some examples, the different responses may be characterized as a non-response, a positive response, or a negative response. A wide variety of factors may influence the degree to which a particular nerve branch responds to electrical stimulation. In some examples, a non-response of a nerve group to electrical stimulation may be caused by a lack of physical contact between an electrode and the nerve or caused by a fluid presence between the electrode and the nerve. In some examples, a non-response also may be caused by a temporary neurapraxia, in which normal nerve conduction fails for some period of time. In some examples, a non-response may be caused by prior permanent damage to the nerve bundle or the nerve as a whole. In some examples, other factors affecting a non-response may comprise nerve diameter and/or relative degree of myelination. In some examples, some combination of these factors and/or other factors may cause a non-response of a nerve fiber group(s) to electrical stimulation. 
     In some examples, a negative response (to electrical stimulation of the nerve via a cuff electrode) may be characterized as a response in which some behavior detracts from the intended response. For instance, in some examples, a negative response may be characterized as an uncomfortable muscle response, such as an uncomfortable motion of a tongue muscle, and/or abrasion on teeth adjacent to the stimulated tongue muscle. In some examples, a negative response may be characterized as an undesirable tongue motion, such as retraction of the tongue when a tongue protrusion was the intended response. 
     In some examples, a positive response may be characterized by muscle contraction of a muscle innervated by a target nerve to which stimulation was intentionally applied via the cuff electrode. In some examples, a positive response may be characterized by at least one muscle causing protrusion of the tongue to maintain or restore airway patency upon electrical stimulation of an upper airway patency-related nerve (e.g. hypoglossal nerve) via a particular stimulation vector(s) via one or more electrode combinations of the cuff electrode. 
     When observing a response to determine whether it is a positive response, a negative response, or a non-response, in at least some examples the primary response is observed near a cathode of a cuff electrode and a non-response observed near an anode of the cuff electrode. In some examples, such as a guarded cathode configuration, the cathode corresponds to one of electrodes  113 A,  113 B (same as  103 B), and/or  113 C while the anode corresponds to electrodes  103 A,  103 C. 
     Via the circumferentially arranged electrodes  113 A,  1138  (same as  103 B),  113 C, the various nerve groups may be selectively stimulated to recruit nerve fiber groups which exhibit a positive response and avoid recruitment of nerve fiber groups which exhibit negative responses or a non-response. 
     In doing so, in some examples the targeting of stimulation to induce positive responses may be implemented via selective stimulation. However, in some examples, the targeting of stimulation may be implemented via selective hyperpolarization which may act to suppress negative responses of some nerve fiber groups. In some examples, a combination of selective stimulation and selective hyperpolarization may be implemented to result in the desired recruitment of and/or inhibiting of particular nerve fiber groups. 
     In some examples, the path of stimulation may be implemented as a short stimulation path or as a long stimulation path based on the position of the electrodes of the cuff electrode which being employed as anodes. In some examples, a short stimulation path may provide for better isolation of nerve fiber groups within a nerve. Stated differently, a short stimulation path may permit more precise targeting of particular nerve fiber groups. In some examples, a short stimulation path may be implemented via using at least some inner electrodes as the anode(s). For instance, in some examples, a short stimulation path may include one or more of the inner axial electrodes  113 A,  113 B,  113 C as a cathode and at least one of the inner axial electrodes  113 A,  113 B,  113 C as an anode. The later described  FIGS. 7G-7H  and  FIGS. 7I-7K  provide some examples of a short stimulation path. 
     In some examples, a long stimulation path may permit an increased response level in the targeted nerve fiber groups for a given energy level delivered to the nerve. In some examples, a long stimulation path may include the outer axial electrodes  103 A,  103 C as anodes and one of the inner axial electrodes  113 A,  113 B (same as  103 B),  113 C as a cathode. The later described  FIGS. 7C-7D  and  FIGS. 7E-7F  provide examples of a long stimulation path. 
     As previously noted, the absence of electrically conductive elements (e.g. electrodes, related connections/wires, etc.) in regions of at least the “upper” portions (e.g.  252 C,  254 C) of the cuff body, which are distal and proximal to the inner axial, circumferentially-oriented array of electrodes  113 A,  1136 ,  113 C may help to minimize or avoid eliciting a response by other nerves and/or other tissue (e.g. muscles) external to the boundaries of the cuff body. 
     With such arrangements in mind, as shown in  FIG. 6A , in some examples electrode  113 C may be used to primarily or exclusively stimulate nerve fiber group  262 A,  262 B (e.g. nerve branches  262 A,  262 B within main nerve  261 ) while electrode  113 B may be used to primarily or exclusively stimulate nerve fiber group  262 C. Meanwhile, via such a selective stimulation arrangement, nerve fiber group  262 D may be excluded from stimulation at least by not activating electrode  113 A and controlling the intensity and area of stimulation field E 1 , E 2  (shown in dashed lines) from electrodes  113 C,  1136 , respectively so as to not capture and stimulate nerve fiber group  262 D. Alternatively, in some examples, hyperpolarization may be applied via electrode  113 A to the nerve fiber group  262 D to inhibit activation of nerve fiber group  262 D. In examples in which the particular nerve may be the hypoglossal nerve, in some examples nerve fiber group  262 D may correspond to a nerve fiber group (e.g. branch) controlling retraction of the tongue while in some examples nerve fiber groups  262 A,  262 B, and/or  262 C may correspond to a nerve fiber group (e.g. branch) controlling protrusion of the tongue. 
       FIG. 6B  is side partial sectional view as taken along lines  6 B- 6 B of  FIG. 6A  and schematically representing a cuff electrode  270  engaging a nerve  261 , according to one example of the present disclosure. 
       FIGS. 7A-7K  are a series of diagrams schematically representing stimulation vectors in association with various electrode array configurations, according to one example of the present disclosure. In  FIGS. 7A-7K , an electrode shown in black indicates that the electrode is being utilized as part of a selected electrode configuration to produce a particular stimulation vector. Electrodes label as “A” are used as anodes, while electrodes labeled as “C” are used as a cathode. It will be understood that in some examples, during a single treatment period (e.g. one nighttime therapy), multiple different electrode configurations can be employed such that the designation of a particular electrode(s) as a cathode or anode may change over time depending on which electrode configuration is employed at a particular point in time. In some examples,  FIGS. 7A-7K  also may be viewed as schematically representing at least an example method of neurostimulation and/or of therapy to treat sleep disordered breathing, such as but not limited to obstructive sleep apnea. 
     As shown in  FIGS. 7A-7B , in this particular configuration  280  of active electrodes, solely the first array of electrodes  103 A- 1030  is employed and in which the outer two electrodes  103 A,  103 C act as anodes while the inner electrode  103 B (same as  113 B) acts as a cathode. The two electrodes  113 A,  113 C remain inactive. 
     This active electrode configuration  280  may produce an electrical stimulation pattern as shown. As shown in  FIG. 7B , in some such examples configuration  280  may produce a field (shown in dashed lines) in which targeted protrusor branches B 1 , B 2  of a nerve (e.g. a hypoglossal nerve) may be captured and stimulated while generally excluding a non-targeted branch B 3  from stimulation. In some examples, the non-targeted branch B 3  may be non-responsive or exhibit a negative response, as previously described. In some examples, a negative response may include being a retractor branch. 
     As shown in  FIGS. 7C-7D , in this particular configuration  284  of active electrodes, the outer two electrodes  103 A,  103 C act as anodes while one of the inner electrodes  113 A or  113 C acts as a cathode. Electrode  103 B remains inactive, as well as one of the electrodes  113 A or  113 C. 
     This active electrode configuration  284  may produce an example electrical stimulation pattern as shown in which a target protrusor branch B 1  may be captured and stimulated while generally excluding non-targeted branches B 2  and B 3 , which may exhibit a negative response or non-response. 
     As shown in  FIGS. 7E-7F , in this particular configuration  286  of active electrodes, the outer two electrodes  103 A,  103 C act as anodes while both of the inner electrodes  113 A and  113 C may act cathodes. Electrode  103 B (same as  113 B) remains inactive. 
     This active electrode configuration  286  may produce an electrical stimulation pattern as shown in which targeted protrusor branches B 1  and B 3  may be captured and stimulated while generally excluding branch B 2  which may exhibit a negative response or a non-response. In some examples, a negative response may include being a retractor branch. 
     However, in some examples, all three inner electrodes  113 A,  113 B,  113 C may be act as cathodes. 
     As shown in  FIGS. 7G-7H , in this particular configuration  288  of active electrodes, only the inner electrodes  113 A,  113 C are active while the outer electrodes  103 A,  103 C remain inactive. 
     As shown in  FIGS. 7I-7K , in this particular configuration  290  of active electrodes, inner electrode  113 B (same as  103 B) is active along with one of electrodes  113 A ( FIG. 7J ) or  113 C ( FIG. 7K ) while the outer electrodes  103 A,  103 C remain inactive. 
     With regard to the examples of  FIGS. 7A-7K , it will be understood that in each instance in which stimulation of a particular nerve branch/group is said to be excluded from stimulation, in some examples hyperpolarization may be applied to the particular nerve branch/group to inhibit its activation. 
       FIG. 8A  is an isometric view schematically representing a cuff electrode  300 , according to one example of the present disclosure. In some examples, cuff electrode  300  comprises at least some of substantially the same features and attributes as cuff electrode  100 ,  200  as previously described in association with at least  FIGS. 1-7K , except having additional electrodes in portions of cuff body  101 ,  201  in which they were omitted in cuff electrode  100 ,  200 . In particular, as shown in  FIG. 8B , electrodes  323 A and  323 C are present in portions  252 A,  252 C of cuff body  301  while electrodes  333 A and  333 C are present in portions  254 A,  254 C of cuff body  301 . With this in mind, cuff electrode  300  in  FIG. 8A  includes an array  330  of electrodes  323 A- 323 C,  313 A- 313 C,  333 A- 333 C in which, in some examples, electrodes  313 A,  313 C correspond to electrodes  113 A,  113 B (also  103 B),  113 C in  FIG. 2 . 
     In some examples, each one of the various electrodes  323 A- 323 C,  313 A- 313 C,  333 A- 333 C is independently programmable/controllable. Accordingly, in general terms, a large variety of different combinations of the electrodes of cuff electrode  300  may be activated to stimulate the nerve. 
     In some examples, the array  332  of outer electrodes  323 A,  323 B,  323 C are electrically common with each other in the circumferential orientation and the array  334  of outer electrodes  333 A,  333 B,  333 C are electrically common with each other in a circumferential orientation. 
     In some examples, the first array  332  of electrodes and the second array  334  of electrodes are electrically common with each other such that all of the respective electrodes  323 A- 323 C of the first array  332  and the respective electrodes  333 A- 333 C of the second array  334  are programmable together as a single electrical element. Meanwhile, each of the inner electrodes  313 A,  313 B,  313 C are programmable independently relative to each other, and independent of the respective outer electrodes  323 A- 323 C,  333 A- 333 C. Accordingly, in this example the inner electrodes  313 A,  313 B,  313 C comprises three independently programmable electrodes while the group of electrodes  323 A- 323 C,  333 A- 333 C comprise a single programmable electrode, such that the cuff electrode  300  has four independently programmable functional electrodes. In some such examples, this configuration may exhibit lower impedance, which may result in more efficient and/or effective stimulation, such as via more effective hyperpolarization of nearby tissues. 
     In some examples, the cuff electrode  300  is associated with an implantable pulse generator (IPG)  1110  ( FIG. 19A-B ) having an external conductive case, which may selectively act as an electrode comparable with the four functional electrodes of cuff electrode  300 . 
     However, in some examples, the first array  332  of outer electrodes  323 A,  323 B,  323 C are electrically common with each other in a circumferential orientation, but electrically independent of the second array  334  of outer electrodes  333 A,  333 B,  333 C, with the respective electrodes  333 A,  333 B,  333 C being electrically common with each other in a circumferential orientation. Via this arrangement, the first array  332  of outer electrodes  323 A,  323 B,  323 C may be activated via a stimulation signal separate from, and independent of the second array  334  of outer electrodes  333 A,  333 B,  333 C such that the activation of the first array  332  is axially unique relative to activation of the second array  334 . In some such examples, this configuration may exhibit lower impedance, which may result in more efficient and/or effective stimulation, such as via more effective hyperpolarization of nearby tissues. 
       FIG. 8B  is a diagram including a plan view of the comprehensive array  330  of electrodes  323 A- 323 C,  313 A- 3130 ,  333 A- 333 C while  FIG. 9  provides a sectional view (as taken along lines  9 - 9  in  FIG. 8A ) of electrodes  313 A,  313 B,  313 C. In some examples, the electrodes  313 A,  313 B,  313 C shown in  FIG. 9  are representative of electrodes  323 A,  323 B,  323 C and electrodes  333 A,  333 B,  333 C having generally uniform circumferential spacing relative to each other. However, in some examples, the circumferential spacing of the electrodes  313 A,  313 B,  313 C may be non-uniform. Moreover, in some examples, instead of having a 3×3 electrode matrix, cuff electrode  300  may comprise a 4×4 or 3×5, 4×6, etc. electrode matrix. 
     In some examples, as shown in  FIGS. 8B-9 , the cuff body  301  includes circumferential portions (e.g.  250 A,  250 B,  250 C) having substantially equal arc lengths (AL 5  or W 5 ; AL 6  or W 6 ; AL 7  or W 7 ). In some examples, at least some of the different circumferential portions have arc lengths which vary from each other. 
     In some examples, the particular arrangement of electrodes depicted in at least  FIGS. 8A-9  may be implemented in a cuff body having a different configuration than the cuff body  301  shown in  FIGS. 8A-9 . In some examples, the particular arrangement of electrodes depicted in  FIGS. 8A-9  may be implemented in the cuff body  101  shown in  FIGS. 1-3  and/or the respective cuff bodies shown in  FIGS. 14A-14B, 18A, 18B . 
     In some examples, in a manner similar to that depicted in  FIGS. 6A-6B  (in which the cuff body releasably contacts a nerve  261 ) and/or  FIGS. 7A-7K , the arrangements shown in  FIGS. 8A, 8B, 9  also may be viewed as schematically representing a method of neurostimulation and/or therapy to treat sleep disordered breathing, such as but not limited to obstructive sleep apnea. It will be understood that the nerve  261  is omitted in  FIGS. 8A, 9  for illustrative clarity in such examples. 
       FIG. 10  is an isometric view schematically representing a cuff electrode  400 , according to one example of the present disclosure. In some examples, cuff electrode  400  comprises at least some of substantially the same features and attributes as cuff electrode  300  of  FIGS. 8A-9 , except for additionally including a pair of ring electrodes  415 A,  415 B on opposite ends of the cuff body  401  and on opposite ends of the array  330  of electrodes  323 A- 323 C,  313 A- 313 C,  333 A- 3330 .  FIG. 10  retains the section lines  9 - 9  to reflect that a cuff electrode  400  depicted in  FIG. 10  may exhibit at least some of substantially the same features and attributes as the cuff electrode  300  represented in the sectional view of  FIG. 9 . Moreover, it will be understood that, in a manner similar to that depicted in  FIGS. 6A-6B  (in which the cuff body releasably contacts a nerve  261 ) and/or  FIGS. 7A-7K , the arrangements shown in  FIGS. 10-11  also may schematically represent a method of neurostimulation and/or therapy to treat sleep disordered breathing, such as but not limited to obstructive sleep apnea. It will be understood that the nerve  261  is omitted in  FIGS. 10-11  for illustrative clarity in such examples. 
     With further reference to  FIG. 10 , in some examples, each ring electrode  415 A,  4156  comprises a split ring electrode having a body  416  extending between two opposite ends  417 A,  4176 , which in turn define a gap G. In some examples, the gap G is sized and positioned to facilitate opening and closing of the cuff body  401  during implanting the cuff electrode  400  to removably encircle a nerve. Accordingly, the gap G in the ring electrodes  415 A,  4156  generally corresponds to and/or overlaps with a point of releasable engagement (e.g.  109  in  FIGS. 1-5B ) between opposing arms of the cuff body (e.g.  101  in  FIGS. 1-5B ). 
     In some examples, the gap G may have a different circumferential position than shown in  FIG. 10 . For instance, gap G may have a circumferential position such as the particular circumferential position for point of releasable engagement  109  of cuff electrode  100  shown in at least  FIGS. 1-5B . 
     In some examples, the ring electrodes  415 A,  4156  have an inner diameter generally corresponding to a diameter of the lumen  140  defined by cuff body  401  in its closed position. In some examples, the body  416  of each ring electrode  415 A,  4156  has an arc length which corresponds to 70 to 90 percent of a circle. 
     In some examples, the respective ring electrodes  415 A,  4156  are retained in position relative to cuff body  401  and electrodes  323 A- 323 C,  313 A- 313 C,  333 A- 333 C via an overmolding, which is independent of the cuff body  401 . In some examples, the overmolding comprises a polyurethane material. In some examples, the overmolding extends from a lead body which extends proximally and/or distally from the cuff body  101 . In some examples, this lead body is the same lead body which supports cuff electrode  400  and which is at least partially incorporated within base  120  of cuff body  101 . 
     In some such examples, the lead body and/or cuff electrode  400  may be molded, extruded, adhesively assembled, and/or formed. However, in some such examples, the electrode array and non-conduction portions of the cuff electrode  400  may be manufactured via a printed circuitry manufacturing process and opposing arms of the cuff electrode (and/or other features which may wrap about a nerve) being formed in a complementary manner with the printed electrode array and non-conductive portions of the cuff electrode  400 . 
     In some examples, the ring electrodes  415 A,  415 B are formed from an electrically conductive material. In some examples, the ring electrodes  415 A,  451 B may be formed from a material which is resilient and/or semi-rigid. 
     In some examples, the ring electrodes  415 A,  415 B may facilitate maintaining a particular position of cuff electrode  400  along a length of the nerve, and may contribute to long term retention of the cuff electrode  400  on the nerve. In one aspect, the resilient and/or semi-rigid material forming the ring electrodes  415 A,  415 B contribute to such position maintenance and long term retention. In some examples, the semi-rigid material forming the ring electrodes  415 A,  415 B exhibits sufficient stiffness to resist undue bending or flexing during maneuvering the cuff electrode  400  into encircling engagement about the nerve. 
     In some examples, the respective ring electrodes  415 A,  415 B are independently programmable/controllable, while in some examples, the respective ring electrodes  415 A,  415 B are electrically common with each other. 
     In some such examples associated with  FIG. 10 , a greater degree of selectivity may be implemented via the increased number of electrode surfaces. In some examples and as previously noted in association with  FIG. 10 , the respective electrodes  323 A,  313 A,  333 A comprise a first axial array  440  while respective electrodes  323 B,  313 B,  333 B comprise a second axial array  442 , and respective electrodes  323 C,  313 C,  333 C comprise a third axial array  444 . 
     In some examples, cuff electrode  400  comprises the ring electrodes  415 A,  415 B and just one of the axial arrays  440 ,  442 ,  444 . In other words, two of the axial arrays  440 ,  442 ,  444  are omitted from cuff electrode  400  while retaining the two ring electrodes  415 A,  415 B. 
     In some examples, cuff electrode  400  comprises just two of the respective axial arrays  440 ,  442 ,  444 . In other words, just one of the axial arrays  440 ,  442 ,  444  is omitted from cuff electrode  400  while retaining the two ring electrodes  415 A,  415 B. 
     In such examples, in which one or two of the axial arrays  440 ,  442 ,  444  are omitted, the remaining axial arrays  440 ,  442 ,  444  may be have a different position (according to a circumferential orientation) than shown in  FIGS. 10-11 . 
       FIG. 11  is a plan view schematically representing the comprehensive array  330  of electrodes  323 A- 323 C,  313 A- 3130 ,  333 A- 333 C and the pair of ring electrodes  415 A,  415 B, according to one example of the present disclosure. In some examples, each ring electrode  415 A,  415 B has an arc length (L 8 ) and a width (W 8 ). In some examples, each ring electrode  415 A,  415 B is spaced apart by a distance D 1  from an end of the comprehensive array  330  of electrodes  323 A- 323 C,  313 A- 3130 ,  333 A- 3330 . 
     In some examples, the particular arrangement of electrodes depicted in at least  FIGS. 10-11  may be implemented in a cuff body having a different configuration of than the cuff body  401  shown in  FIG. 10 . In some examples, the particular arrangement of electrodes depicted in  FIG. 10  may be implemented in the cuff body  101  shown in  FIGS. 1-5B  and/or the respective cuff bodies shown in at least  FIGS. 14A-14B, 18A-18B . 
       FIG. 12  is an isometric view schematically representing a cuff electrode  500 , according to one example of the present disclosure.  FIG. 13A  is a plan view schematically representing the array  530  of electrodes  520 ,  323 B- 323 C,  313 B- 313 C, and  313 B- 313 C of cuff electrode  500  when laid out flat, according to one example of the present disclosure.  FIG. 13B  is a plan view schematically representing the array  530  of electrodes  520 ,  323 B- 323 C,  313 B- 313 C, and  313 B- 313 C of cuff electrode  500  as in  FIG. 13B , except with elongate electrode  520  in a different circumferential position relative to the other rows of electrodes (in their axial orientation). 
     In some examples, cuff electrode  500  comprises at least some of substantially the same features and attributes as cuff electrode  300  as previously described in association with at least  FIG. 8A-9 , except having a single elongate electrode  520  in cuff electrode  500  ( FIG. 12 ) instead of electrodes  323 A,  313 A,  333 A in cuff electrode  300  ( FIG. 8A ). With this in mind, cuff electrode  500  in  FIG. 12  includes an array  530  of electrodes  520 ,  323 B- 323 C,  313 B- 313 C, and  333 B- 333 C. Via this arrangement, the elongate electrode  520  is common axially to all of the other electrodes  323 B- 323 C,  313 B- 313 C, and  333 B- 333 C of array  530 . In some examples, each one of the various electrodes  520 ,  323 B,  323 C,  313 B,  313 C,  333 B, and  333 C is independently programmable/controllable. Accordingly, in general terms, a large variety of different combinations of the electrodes of cuff electrode  300  may be activated to stimulate the nerve. 
     In some examples, electrodes  323 B,  323 C are electrically common with each other to function as a single activatable electrical element, electrodes  3138 ,  313 C are electrically common with each other to function as a single activatable electrical element, and electrodes  333 B,  333 C are electrically common with each other to function as a single activatable electrical element. Via this arrangement, different axial points along length of nerve may be stimulated. 
     In some such examples, this configuration may permit use of lower stimulation amplitudes via the relatively larger surface area of the elongate third electrode  520 . Upon positioning the electrode configuration in at least some locations, this effect, may in turn, increase generator efficiency and may increase nerve capture. In some examples, the elongate third electrode  520  has a length at least substantially equal to the distance of spacing between two outer electrodes (e.g.  323 C,  333 C) of one of the axial arrays of electrodes. As such, in some examples, the elongate third electrode  520  may sometimes be referred to as being generally coextensive with one or more of the axial arrays of electrodes (e.g.  323 C,  313 C,  333 C). More particularly, in some examples, the elongate third electrode  520  is generally coextensive with outer ends  339 A,  339 B of electrodes  323 C,  333 C. In some examples, the elongate third electrode  520  is generally coextensive at least through inner ends  338 A,  338 B of the outer electrodes (e.g.  323 C,  333 C) of one of the axial arrays of electrodes. 
     In some examples, the elongate third electrode  520  has an arc length (in the circumferential orientation) which is substantially the same as an arc length of the other electrodes of the cuff electrode. However, in some examples, the elongate third electrode  520  has an arc length (in the circumferential orientation) which substantially greater than the arc length of the other electrodes of the cuff electrode. In some such examples, this greater arc length may enable a reduction in overall cuff length, which in turn may enable greater maneuverability of the cuff body to enhance surgical delivery of the cuff. In some examples, an elongate third electrode  520  may located, in a circumferential orientation, closer to or overlapping with a spine (e.g. base  120  in  FIG. 1 ) of the cuff/lead so as to minimize any impact on overall cuff flexibility. 
     In some examples, the particular arrangement of electrodes depicted for cuff electrode  501  in  FIG. 12  may be implemented in a cuff body having a different configuration than the cuff body  501  shown in  FIG. 12 . In some examples, the particular arrangement of electrodes depicted in  FIG. 12  may be implemented in the cuff body  101 ,  201  shown in  FIGS. 1-6B  and/or the respective cuff bodies shown in  FIGS. 14A-14B and 18A, 18B . 
       FIG. 12  retains the section lines  9 - 9  to reflect that a cuff electrode  500  may exhibit at least some of substantially the same features and attributes as the cuff electrode  300  represented in the sectional view of  FIG. 9 . Moreover, it will be understood that, in a manner similar to that depicted in  FIGS. 6A-6B  (in which the cuff body releasably contacts a nerve  261 ) and/or  FIGS. 7A-7K , the arrangements shown in  FIGS. 12-13B  also may schematically represent a method of neurostimulation and/or therapy to treat sleep disordered breathing, such as but not limited to obstructive sleep apnea. It will be understood that the nerve  261  is omitted in  FIGS. 12-13B  for illustrative clarity in such examples. 
       FIG. 14A  is a sectional view schematically representing a cuff electrode  600 , according to one example of the present disclosure. 
     As shown in  FIG. 14A , in at least some examples, cuff electrode  600  comprises at least some of substantially the same features and attributes as the cuff electrode  100 ,  200  of  FIGS. 1-6B  and  FIGS. 7A-7K . For instance, in some examples cuff electrode  600  may have a first array  610  of electrodes  603 A,  603 B,  603 C (e.g. first electrodes) extending axially like electrodes  103 A,  103 B,  103 C ( FIGS. 1-2 ) and a second array  612  of electrodes  613 A,  613 B,  613 C (e.g. second electrodes) extending in a circumferential orientation perpendicular to the axial orientation with electrode  613 B also acting as electrode  603 B. Accordingly, in such a configuration some portions (e.g.  252 A,  254 A,  252 C,  254 C in  FIG. 5A ) of a cuff body  601  omits electrodes and define cuff body portions free from electrically conductive elements. 
     However, unlike the configuration of electrodes  113 A,  113 B,  113 C in  FIGS. 1-6B , in the cuff electrode  600  of  FIG. 14A  two electrodes  613 C,  613 A are included on a single arm (e.g. first arm  634 ) while the other arm  650  omits any electrodes. Moreover, the third electrode  613 B (same as  103 B) is located at or near base  620 . In such a configuration, the electrodes  613 C,  613 A are located away from the lead body attachment/spine, which in some examples may contribute to generally equal circumferential spacing between the three inner electrodes  613 C,  613 A,  613 B. Other differences relative to the cuff electrode  100 ,  200  in  FIGS. 1-6B  are described further below and/or are observable from  FIG. 14A . 
     As further shown in  FIG. 14A , the cuff body  601  comprises a first arm  634  and a second arm  650 . The first arm  634  has a proximal portion  635  and an opposite distal portion  637  having distal end  636 . The first arm  634  also comprises an outer surface  638  and an inner surface  639 , which at least partially defines nerve-contact surface  641  of cuff body  601 . The proximal portion  635  of first arm  634  extends from the base  620  and has a thickness T 1 . In some examples, the first arm  634  has at least one segment with a thickness which varies. In some such examples, the at least one segment of varying thickness comprises at least one segment of increased thickness relative to other portions of the first arm  634 . In some examples, the at least one segment of varying thickness may be implemented to house electrodes  613 C,  613 A. In some examples, the at least one segment of first arm  634  having the varying thickness corresponds to an outer circumferential portion of a cuff body, such as portion  651 C in  FIG. 15A , portions  652 C,  651 C,  654 C in  FIGS. 15B, 15C, 15D , portion  721 B in  FIG. 17A , and portions  722 B,  721 B,  724 B in  FIG. 17B-17C . 
     In some examples, the at least one segment of first arm  634  exhibiting varying thickness may be implemented as protrusions  615 B,  615 C which are oriented inwardly within the lumen  640 C defined by the cuff body  601  and which partially define nerve-contact surface  641  of lumen  640 C. In some instances, these inwardly-oriented protrusions  615 A,  615 C may be referred to as inward protrusions or internal protrusions. In some examples, each inwardly-oriented protrusion  615 A,  615 C comprises a generally convex shape, which stands in contrast to the generally concave shape of portions of the nerve-contact surface  641  other than inwardly-oriented protrusions  615 A,  615 C. In some examples, at its apex, each protrusion  615 A,  615 C has a thickness T 2 , which is substantially greater than the thickness T 1  of the non-protruding portions of the first arm  634 . In some examples, T 2  is at least two times T 1 . In some such examples, this increased thickness may ease molding of electrodes (e.g.  613 C,  613 A) into the arm  634  of the cuff body, and the cuff body generally. In some examples, the protrusions  615 A,  615 C are circumferentially spaced apart by a distance equal to the equal circumferential spacing of electrodes  613 A,  613 B,  613 C. 
     While  FIG. 14A-14B  depicts inwardly-oriented protrusions  615 C,  615 A, and while  FIGS. 18A-18B  depict outwardly-oriented protrusions, it will be understood that some examples may include similar protrusions in which one or more such protrusions (housing electrodes  613 C,  613 A) may include both an inwardly-oriented portion and an outwardly-oriented portion and/or may include shapes other than those shown in  FIGS. 14A-14B or 18A-18B  to provide a relatively increased thickness in an area of the arm to at least partially house electrodes. 
     Each protrusion  615 C,  615 A at least partially houses the respective electrodes  613 C,  613 A. In some examples, each protrusion  615 C,  615 A has a volume sufficient to securely retain each electrode  613 C,  613 A, associated hardware, and conductive lead wires that extend through select portions (e.g. inner axial portions ( 651 C,  651 B in  FIG. 15A ) of cuff body  601 . As shown in  FIG. 14A , each protrusion  615 C,  615 A may be formed and/or shaped to expose at least a portion of the respective electrodes  613 C,  613 A at the nerve-contact surface  641  of the cuff body  601  to engage the nerve. 
     The electrodes  613 C,  613 A may be implemented in a variety of shapes, such as but not limited to the spherical shape shown in the sectional view of  FIG. 14A . For instance, the electrodes may have a cylindrical shape with an outer curved surface exposed at the nerve-contact surface  641  of the lumen  640 . In other instances, as shown later in  FIG. 14B , electrodes  663 C,  663 A may have an arc shape which matches the general contour of the protrusions  665 C,  665 A. 
     In some examples, the inwardly-oriented protrusions  615 C,  615 A may cause the exposed electrode surface  618 C,  618 A to define a radius R 2  relative to center of lumen  640 C that is less than a radius R 1  of remainder of nerve-contact surface  641  of the lumen. In some examples, R 2  is substantially less than R 1 . In some examples, the varying thickness and radius of the first arm  634  may sometimes be referred to as a circumferential profile of the nerve-contact surface  641  extending along first arm  634 . 
     In some examples, the inwardly-oriented protrusions in which the electrodes are housed may enhance operable coupling of the electrode relative to one or more nerve groups within the nerve. For instance, in at least some examples, at least some branches/fibers within the nerve may adapt and flow around/about the respective protrusions, thereby resulting in the various nerve branches being in close proximity to the respective electrodes (within the respective protrusions) to establish good connectivity between the nerve (branches) and the electrodes. 
     The second arm  650  comprises a proximal portion  655  and a distal portion  622  with a distal end  656 . The proximal portion  655  has a thickness T 3  while the distal portion  622  has a thickness T 4 . In some examples, an arc length of the distal portion  622  of second arm  650  overlaps a substantial majority of the arc length of the first arm  634 . In some examples, the overlap corresponds to at least about 30 degrees of arc length. 
     In some examples, second arm  650  comprises a transition portion  669  defining a transition between the proximal portion  655  and distal portion  622 . In some examples, transition portion  669  includes a shelf  670  defined by an end of proximal portion  655  of second arm  650  and includes a proximal end  624  of distal portion  622  of second arm  650 . 
     While generous spacing is shown in  FIG. 14A  between distal end  636  of first arm  634  and the shelf  670  of second arm  650 , it will be understood that it is intended that shelf  670  provides an area by which distal end  636  of first arm  634  may make releasable contact with second arm  650 . This arrangement limits the extent of rotational movement of first arm  634 , which may bolster structural integrity of cuff body  101  and also defines minimum diameter of lumen  640 C so as to prevent undue pressure and/or constriction on a nerve. 
     Moreover, the greater thickness T 3  of the proximal portion  655  of second arm  650  provides additional structural strength to support releasable contact from distal end  636  of first arm  634  and/or to maintain a shape of lumen  640 C. 
     In some examples, the shelf  670  has a width W generally the same as or wider than the width W of the distal end  636  of the first arm  634 . 
     In addition to the shelf  670 , the transition portion  669  includes the distal portion  622  extending directly from the proximal portion  655 . In some examples, the distal portion  622  has a generally uniform thickness T 4  throughout its length. In some examples, the distal portion  622  of the second arm  650  has an inner surface  626  defining a generally constant radius of curvature while the outer surface  638  of the first arm  634  has a generally constant radius of curvature that generally matches the radius of curvature of the inner surface  626  of the distal portion  622  of the second arm  650 . Via this arrangement, in its overlapping relation with the at least the first arm  634 , the distal portion  622  of the second arm  650  lies generally flat against the first arm  634 . This arrangement may enhance the integrity and holding strength of cuff body  601  relative to the nerve, while simultaneously accommodating any temporary nerve swelling upon implantation and/or accommodating different size nerves. 
     Each arm  634 ,  650  is shaped and formed of a resilient material such that the opposingly-oriented arms  634 ,  650  are biased into the configuration shown in  FIG. 14A  to remain in a releasably secured position about a nerve. However, each arm  634 ,  650  has sufficient flexibility to permit being manipulation of the distal portion  622  of second arm  650  and distal portion  637  of first arm  634  to enable opening cuff body  601  to receive nerve within lumen  640 C, and upon release of the respective arms  634 ,  650 , to return the cuff body  601  to the closed configuration shown in  FIG. 14A . 
     In defining different circumferential portions and/or different axial portions of the cuff body  601  of  FIG. 14A , it will be understood that in comparison to the example of  FIGS. 1-6B , in some examples the first arm  634  and the proximal portion  655  of the second arm  650  may be considered analogous to the first arm  134  and to the second arm  150 , respectively. 
       FIG. 14B  is sectional view schematically representing a cuff electrode  660 , according to one example of the present disclosure. In some examples, the cuff electrode  660  (including cuff body  661 ) comprises at least some of substantially the same features and attributes of cuff electrode  600  of  FIG. 14A  (including cuff body  601 ), except for the inwardly-oriented protrusions  665 C,  665 A having a lower radial profile (i.e. less thickness) and the electrodes  663 C,  663 B,  663 A having an arc shape instead of a spherical or cylindrical shape. In some examples, a thickness T 5  of each inwardly-oriented protrusion  665 C,  665 A has a thickness T 5  is substantially less than a thickness T 2  of the inwardly-oriented protrusions  615 C,  615 A of the cuff electrode  600  in  FIG. 14A . In some examples, the thickness T 5  is no more than twice the thickness T 1  of the proximal portion  635  of the first arm  634 . 
     In some examples, the arc-shaped electrodes  663 C,  663 A comprise a convex-shaped electrode contact surface  668 C,  668 A within lumen  640 B for releasably contacting a nerve. In some examples, the arc-shaped electrode  663 B comprises a concave-shaped electrode contact surface  668 B for releasably contacting the nerve within lumen  640 B. 
     It will be understood that in some examples, electrodes  663 C,  663 A may have shapes other than an arc-shape. For instance, the electrodes  663 C,  663 A may be concave or even flat (e.g. not curved), or other convex-shaped, disc-shaped, etc. with adjacent portions of the protrusion supporting the electrode shape in a complementary manner to yield a suitable nerve-electrode interface. 
       FIG. 15A  is a diagram including a plan view schematically representing a nerve-contact surface  641  and an electrode pattern associated with the cuff electrodes  600 ,  660  in  FIGS. 14A-14B , according to one example of the present disclosure. In some examples, the cuff electrode  600  of  FIG. 15A  comprises at least some of substantially the same features and attributes as cuff electrode  600  ( FIG. 14A ) and cuff electrode  660  ( FIG. 14B ). For simplicity, further discussion regarding  FIG. 15A  will refer solely to cuff electrode  600  even though it will be applicable to both cuff electrodes  600  ( FIG. 14A ),  660  ( FIG. 14B ). 
     In some examples, the cuff electrode  600  in  FIG. 15A  comprises different circumferential portions and axial portions of a cuff body  601  in the substantially the same manner as the different portions of the cuff body  101 ,  201  for the cuff electrode in  FIG. 3-5B . With this in mind, the inner circumferential portions  652 B,  651 B,  654 B of cuff body  101  house electrodes  603 A,  603 B (same as  613 B),  603 C, respectively, while the outer circumferential portion  651 C (also an inner axial portion) houses electrodes  613 A,  613 C. In some examples, the outer circumferential portion  651 C generally corresponds to at least the distal portion  637  of first arm  634  ( FIG. 14A ). 
     As shown in  FIG. 15A , in some examples the circumferential array of electrodes  613 B,  613 A,  613 C are equally spaced apart, as represented by distances D 1  and D 2 . 
     Meanwhile, the dashed lines  615 A,  615 C in  FIG. 15A  represent the inner protrusions  615 A,  615 C ( FIG. 14A ) when the inner protrusions are implemented as generally circular elements within portion  651 C of cuff body  601 . In some such configurations, the generally circular elements may facilitate molding and/or retention of the electrodes within the cuff body. 
     However, in some examples, as shown in  FIG. 15B , the inner protrusions  615 A,  615 C are implemented as elongate elements represented by shaded regions  669 A,  669 C which may extend a length (L 1 ) of the cuff body  601 . In some such configurations, the elongate elements may facilitate molding and/or retention of the electrodes within the cuff body, as well as routing of wires within/through the cuff body. 
       FIG. 15C  is a diagram including a plan view schematically representing a nerve-contact surface of a cuff electrode  700  and electrode pattern relative to some circular-shaped, inwardly-oriented protrusions of a nerve-contact surface, according to one example of the present disclosure. The cuff electrode  700  comprises at least some of substantially the same features as cuff electrode  600  in  FIG. 15A , except having electrodes  623 A,  623 C in portion  652 C and electrodes  633 A,  633 C in portion  654 C with each of these electrodes housed in an inwardly-oriented protrusion  625 A,  625 C,  635 A,  635 C, respectively with inwardly-oriented protrusions  625 A,  625 C,  635 A,  635 C having substantially the same features as inwardly-oriented protrusions  615 A,  615 C ( FIG. 14A ) or  665 A,  665 C ( FIG. 14B ). 
     In some examples, the general electrode pattern in cuff electrode  700  comprises at least some of substantially the same features and attributes as cuff electrode  300  in  FIG. 8A-9 , as least to the extent that cuff electrode  700  comprises three axial arrays of electrodes and the manner in which they may operate together or independently. 
     In some examples, as shown in  FIG. 15D , the inwardly-oriented protrusions housing the electrodes  623 A,  623 C (in portion  652 C),  613 A,  613 C (in portion  651 C),  633 A,  633 C (in portion  654 C) are implemented as elongate elements represented by shaded regions  669 A,  669 B in a manner similar to that shown in  FIG. 15B . 
     It will be understood that, in a manner similar to that depicted in  FIGS. 6A-6B  (in which the cuff body releasably contacts a nerve  261 ) and/or  FIGS. 7A-7K , the arrangements shown in  FIGS. 14A-14B, 15A-15C  also may schematically represent a method of neurostimulation and/or therapy to treat sleep disordered breathing, such as but not limited to obstructive sleep apnea. It will be understood that the nerve  261  is omitted in  FIGS. 14A-14B, 15A-15C  for illustrative clarity in such examples. 
       FIG. 16  is a diagram including an isometric view schematically representing different portions of a cuff body  720  for a cuff electrode like that of  FIGS. 14A-14B , according to one example of the present disclosure. In some examples, the cuff body  720  comprises at least some of substantially the same features and attributes as the cuff body  101 ,  201  ( FIGS. 1-6B ), except with cuff body apportioned as two circumferential portions instead of as three (two outer, one inner) circumferential portions. Accordingly, in some examples, the cuff body  720  includes a first circumferential portion  710  and a second circumferential portion  712 . In some examples, the respective first and second circumferential portions  710 ,  712  may sometimes be referred to as first and second half portions or as an upper half portion  710  and lower half portion  712 . In some instances, the lower half portion  712  may sometimes be referred to as a lower circumferential portion while the upper half portion  710  may sometimes be referred to as an upper circumferential portion. 
     In some examples, the lower half portion  712  has an arc length or width W 11 , while the upper half portion  710  has an arc length or width W 12 , which is generally equal to W 11 . 
     Accordingly, as shown in  FIG. 17A , electrodes  603 A,  603 B,  603 C extend axially with one electrode present in each of the portions  722 A,  721 A,  724 A of cuff body  720  while electrodes  613 A,  613 B,  613 C extend in a circumferential orientation with both electrodes  613 A,  613 C residing in portion  721 B. Portions  722 B,  724 B omit any electrodes. As represented via the dashed lines  615 A,  615 C, each electrode  613 A,  613 C is housed in a circular-shaped inwardly-oriented protrusion in a manner as previously described in association with at least  FIG. 15A, 15C  to implement housing an electrode via the inwardly-oriented protrusions as in  FIG. 14A or 14B . 
     In some examples, each of the upper circumferential, outer axial cuff body portions  722 B,  724 B omit electrodes (and therefore are generally electrically conductive-free portions). 
       FIG. 17B  is a diagram including a plan view schematically representing a nerve-contact surface  641  of a cuff electrode  740  and electrode pattern relative to some circular-shaped inwardly-oriented protrusions of a nerve-contact surface, according to one example of the present disclosure. The cuff electrode  740  comprises at least some of substantially the same features as cuff electrode  700  in  FIG. 15C , except for cuff body  741  apportioned as two circumferential portions rather than thee circumferential portions (two outer, one inner) in  FIG. 15C . Accordingly, as shown in  FIG. 17B , in cuff electrode  740  the portion  722 B includes electrodes  623 A,  623 C while portion  724 B includes electrodes  633 A,  633 C. Each of these electrodes are housed in an inwardly-oriented protrusion  625 A,  625 C,  635 A,  635 C, respectively with inwardly-oriented protrusions  625 A,  625 C,  635 A,  635 C having substantially the same features as inwardly-oriented protrusions  615 A,  615 C ( FIG. 14A ) or  665 A,  665 C ( FIG. 14B ). 
     In some examples, the general electrode pattern in cuff electrode  740  in  FIG. 17B  comprises at least some of substantially the same features and attributes as cuff electrode  300  in  FIG. 8A-9 , as least to the extent that cuff electrode  740  comprises three axial arrays of electrodes and the manner in which they may operate together or independently. 
     In some examples, as shown in  FIG. 17C , a cuff electrode  750  includes inwardly-oriented protrusions (to house the electrodes) implemented as elongate elements represented by shaded regions  669 A,  669 B in a manner similar to that shown in  FIG. 15B . 
     With further reference to the example of  FIG. 17C  in which the inwardly-oriented protrusions are implemented as elongate elements (i.e. shaded regions  669 A,  669 C), additional electrodes  623 A,  623 C may be implemented in portion  722 B) and additional electrodes  633 A,  633 C may be implemented in portion  724 B. In such examples, the general electrode pattern in cuff electrode  750  in  FIG. 17C  comprises at least some of substantially the same features and attributes as cuff electrode  300  in  FIG. 8A-9 , as least to the extent that cuff electrode  700  would comprise three axial arrays of electrodes and the manner in which they may operate together or independently. 
     It will be understood that, in a manner similar to that depicted in  FIGS. 6A-6B  (in which the cuff body releasably contacts a nerve  261 ) and/or  FIGS. 7A-7K , the arrangements shown in  FIGS. 16-17C  also may schematically represent a method of neurostimulation and/or therapy to treat sleep disordered breathing, such as but not limited to obstructive sleep apnea. It will be understood that the nerve  261  is omitted in  FIGS. 16-17C  for illustrative clarity in such examples. 
       FIG. 18A  is a sectional view schematically representing cuff electrode  900 , according to one example of the present disclosure. In some examples, cuff electrode  900  comprises at least some of substantially the same features and attributes as cuff electrode  600 ,  660  in  FIG. 14A-14B , except for having outwardly-oriented protrusions  915 C,  915 A to at least partially house electrodes  913 C,  913 A instead of the inwardly-oriented protrusions  615 C,  615 A of the cuff electrode  600  in  FIG. 14A-14B . 
     In some examples, the cuff electrode  900  has a second arm  950  like second arm  650  of cuff electrode  600  in  FIG. 14A-14B , except with the second arm  950  having a proximal portion  955  with a thickness T 7  greater than a thickness T 3  ( FIG. 14A ) of proximal portion  655  of second arm  650  of cuff body  601 . In some examples, the greater thickness T 7  is provided so that the inner surface of proximal portion  955  (of second arm  950 ) defining part of nerve-contact surface  941  will match and/or complement the radius of the other portions of the nerve-contact surface  941  of cuff body  901 . This arrangement also positions the proximal portion  928  of the distal portion  922  of second arm  950  to orient the contour of the inner surface  926  of the distal portion  922  to accommodate the outwardly-oriented protrusions  915 C,  915 A in a manner such that the bias of the distal portion  922  will result in the distal portion  922  wrapping in a complementary relationship about the outer surface  938  (including the outward protrusions  915 C,  915 A) of the first arm  934 . 
     As further shown in  FIG. 18A , like in the example of  FIG. 14A  the first arm  934  comprises a proximal portion  935  extending from a base  920 A of cuff electrode  900  and comprises an opposite distal portion  937  having a distal end  936 . Moreover, the second arm  950  comprises a proximal portion  955  and an opposite distal portion  922  having distal end  956 . 
     In contrast with the examples in  FIGS. 14A-14B , in the present arrangement of outwardly-oriented protrusions  915 C,  915 A, the extra space involved in housing the electrodes  913 C,  913 A (and related conductive wires) is oriented outward away from the nerve-contact surface  941 . Via this arrangement the nerve-contact surface  941  of the cuff body  901  defined by lumen  940 C maintains a generally uniform radius of curvature such that the contact surface  918 C,  918 A of the electrodes  913 C,  913 A are generally flush with other portions of the nerve-contact surface  941  of the cuff body  901 . Via this arrangement, the nerve-contact surface  941  of the cuff electrode  900  as a whole is highly complementary of the outer surface/circumference of the nerve to which it is engaged. 
       FIG. 18B  is a sectional view schematically representing a cuff electrode  960 , according to one example of the present disclosure. In some examples, cuff electrode  960  comprises at least some of substantially the same features and attributes as cuff electrode  900  ( FIG. 18A ), except having arc-shaped electrodes  963 C,  963 A instead of spherically-shaped or cylindrically-shaped electrodes  913 C,  913 A ( FIG. 18A ). In some examples, a thickness T 8  of the outward protrusions  965 C,  965 A is less than a thickness T 6  of the outward protrusions  915 C,  915 A ( FIG. 18A ) because of a lower radial profile of the arc-shaped electrodes  963 C,  963 A. In some examples, the electrodes  963 C,  963 A have concave-shaped nerve-contact surfaces  968 C,  968 A which are generally flush with the nerve-contact surface  941  of the cuff body  961 . Via this arrangement, while the outwardly-oriented protrusions  965 C,  965 A accommodate the volume of the electrodes  963 C,  963 A and connected conductive lead wires (and associated connection structures), the nerve-contact surface  941  of the cuff body  961  retains a generally uniform radius which may facilitate close engagement relative to the nerve. 
     As further shown in  FIG. 18B , like in the example of  FIG. 18A  the first arm  934  comprises a proximal portion  935  extending from a base  920 B of cuff electrode  960  and comprises an opposite distal portion  937  having a distal end  936 . Moreover, the second arm  950  comprises a proximal portion  955  and an opposite distal portion  922  having distal end  956 . As further shown in  FIG. 18B , in some examples, the arc-shaped electrodes  963 C,  963 B,  963 A comprise a concave-shaped electrode contact surface  968 C,  968 B,  968 A of nerve-contact surface  941  within lumen  940 C for releasably contacting a nerve. 
     In some examples, the respective cuff electrode  900  and  960  of  FIGS. 18A, 18B  may comprise any one of (or combinations of) the various electrode configurations and/or cuff body configurations as previously described in association with  FIGS. 15A-15D, 16, 17A-17C , except for being implemented with outwardly-oriented protrusions ( 915 C,  915 A,  965 C,  965 A in  FIGS. 18A, 18B ) instead of with inwardly-oriented protrusions ( 615 C,  615 A,  665 C,  665 A in  FIGS. 14A, 14B ). 
     In some examples, the electrodes  613 C,  613 B,  613 A ( FIG. 14A ), electrodes  663 C,  663 B,  663 A ( FIG. 14B ), electrodes  913 C,  913 B,  913 A ( FIG. 18A ), and/or electrodes  963 C,  963 B,  963 A ( FIG. 18B ) may be implemented within a cuff body of a cuff electrode having at least some of substantially the same features and attributes as one of the cuff electrodes described in Bonde et al. U.S. Pat. No. 9,227,053, “Self-Expanding Electrode Cuff”, issued on Jan. 5, 2016, and in Bonde et al. U.S. Pat. No. 8,340,785, “Self-Expanding Electrode Cuff”, issued on Dec. 25, 2012, both of which are herein incorporated by reference. 
     In some examples, an implantable pulse generator (IPG)  1110  ( FIG. 19A, 19B ) forms part of a system including the cuff electrode  900 ,  960  and in which at least one electrode(s) may be located on a housing of the pulse generator IPG  1110 . 
     It will be understood that, in a manner similar to that depicted in  FIGS. 6A-6B  (in which the cuff body releasably contacts a nerve  261 ) and/or  FIGS. 7A-7K , the arrangements shown in  FIGS. 18A, 18B  also may be understood as schematically representing a method of neurostimulation and/or therapy to treat sleep disordered breathing, such as but not limited to obstructive sleep apnea, with nerve  261  omitted from  FIGS. 18A-18B  for illustrative clarity in such examples. 
       FIG. 19A  is a block diagram schematically representing a neurostimulation system  1100 , according to one example of the present disclosure. System  1100  comprises a pulse generator  1110 , lead body  1102 , and cuff electrode  1104  supported by the lead body  1102 . In some examples, the cuff electrode  1104  comprises any one of the cuff electrodes as described in association with at least  FIGS. 1-18B ,  FIGS. 24-27 , and/or combinations of some features of such cuff electrodes. In some examples, neurostimulation system  1100  comprises a totally implantable system. 
       FIG. 19B  is a block diagram schematically representing a neurostimulation system  1150 , according to one example of the present disclosure. System  1150  comprises a pulse generator  1110  and a leadless cuff electrode  1154 . In some examples, the cuff electrode  1154  comprises any one of the cuff electrodes as described in association with at least  FIGS. 1-18B ,  FIGS. 24-27 , and/or combinations of some features of such cuff electrodes. In some examples, neurostimulation system  1150  comprises a totally implantable system. However, in some examples, the pulse generator  1110  or a portion of the pulse generator  1110  is located external to the patient. The cuff electrode  1154  is in wireless communication with the pulse generator  1110  and/or related components to manage therapy, including applying electrical stimulation. Accordingly, in some examples the cuff electrode  1154  includes and/or is associated with an antenna and related circuitry to implement such wireless communication. 
       FIG. 20  is a block diagram schematically representing a control portion  1700 , according to one example of the present disclosure. In some examples, control portion  1700  includes a controller  1702  and a memory  1704 . In some examples, control portion  1700  provides one example implementation of a control portion forming a part of and/or implementing the implantable medical devices and methods as represented throughout the present disclosure in association with  FIGS. 1-29B . 
     In general terms, controller  1702  of control portion  1700  comprises at least one processor  1703  and associated memories. The controller  1702  is electrically couplable to, and in communication with, memory  1704  to generate control signals to direct operation of at least some components of the devices, elements, components, functions, methods, etc. described throughout the present disclosure. In some examples, these generated control signals include, but are not limited to, employing manager  1705  stored in memory  1704  to manage therapy for sleep disordered breathing, including but not limited to applying nerve stimulation, in the manner described in at least some examples of the present disclosure. In some examples, such generated control signals may at least partially control selective stimulation via the different electrodes on a cuff electrode. It will be further understood that control portion  1700  (or another control portion) may also be employed to operate general functions of the various devices and/or components thereof described throughout the various examples of the present disclosure. 
     In response to or based upon commands received via a user interface (e.g. user interface  1710  in  FIG. 21 ) and/or via machine readable instructions, controller  1702  generates control signals to implement therapy (including but not limited to nerve stimulation) and/or circuitry control in accordance with at least some of the previously described examples of the present disclosure. In some examples, controller  1702  is embodied in a general purpose computing device while in some examples, controller  1702  is incorporated into or associated with at least some of the associated components of the devices as described throughout the present disclosure. 
     For purposes of this application, in reference to the controller  1702 , the term “processor” shall mean a presently developed or future developed processor (or processing resources) that executes sequences of machine readable instructions contained in a memory. In some examples, execution of the sequences of machine readable instructions, such as those provided via memory  1704  of control portion  1700  cause the processor to perform actions, such as operating controller  1702  to implement sleep disordered breathing (SDB) therapy (including but not limited to nerve stimulation), as generally described in (or consistent with) at least some examples of the present disclosure. The machine readable instructions may be loaded in a random access memory (RAM) for execution by the processor from their stored location in a read only memory (ROM), a mass storage device, or some other persistent storage (e.g., non-transitory tangible medium or non-volatile tangible medium, as represented by memory  1704 . In some examples, memory  1704  comprises a computer readable tangible medium providing non-volatile storage of the machine readable instructions executable by a process of controller  1702 . In some examples, hard wired circuitry may be used in place of or in combination with machine readable instructions to implement the functions described. For example, controller  1702  may be embodied as part of at least one application-specific integrated circuit (ASIC). In at least some examples, the controller  1702  is not limited to any specific combination of hardware circuitry and machine readable instructions, nor limited to any particular source for the machine readable instructions executed by the controller  1702 . 
       FIG. 21  is a block diagram schematically representing user interface  1710 , according to one example of the present disclosure. In some examples, user interface  1710  forms part or and/or is accessible via a device external to the patient and by which the implantable medical device (or portions thereof) may be at least partially controlled and/or monitored. 
     In some examples, user interface  1710  comprises a user interface or other display that provides for the simultaneous display, activation, and/or operation of features and attributes of an implantable medical device. In some examples, at least some portions or aspects of the user interface  1710  are provided via a graphical user interface (GUI). In some examples, as shown in  FIG. 21 , user interface  1710  includes display  1712  and input  1714 . 
       FIG. 22A  is flow diagram schematically representing an example method  2000  of selective stimulation. As shown in  FIG. 22A , in some examples method  2000  comprises arranging at least three inner electrodes circumferentially spaced apart about a cuff body (at  2010 ) and selectively stimulating at least one nerve branch within a nerve via a subset of the three inner electrodes in combination with two outer electrodes axially spaced apart from the inner electrodes (at  2012 ). In some examples, one or more of the inner electrodes may serve as an anode while the outer electrodes may serve as a cathode(s) to provide a guarded cathode arrangement. 
     In some examples, method  2000  may be implemented via at least some of substantially the same features and attributes as any one of (or a combination of) the devices, cuff electrodes, cuff bodies, electrode configurations, etc. as described in association with at least  FIGS. 1-21 and/or 24-29B . 
     In addition, various additional aspects of method  2000  are presented below. 
     As shown in  FIG. 22B  at  2020 , in some examples method  2000  may further comprise arranging a second array of at least two outer electrodes axially along a first orientation perpendicular to the second orientation and on respectively opposite ends of the first array, with each respective outer electrode spaced axially apart from the first array. 
     As shown at  2025  in  FIG. 22C , in some examples method  2000  may further comprise selectively stimulating at least the first nerve branch with two electrodes of the first array while generally excluding a second nerve branch from stimulation. 
     As shown at  2030  in  FIG. 22D , in some examples method  2000  may further comprise at least one of not activating a third electrode of the first array and activating the third electrode of the first array to selectively at least partially hyperpolarize the second nerve branch. 
     As shown at  2035  in  FIG. 22E , in some examples method  2000  may further comprise selectively stimulating at least the first nerve branch via selectively stimulating the first nerve branch via a first electrode of the first array and separately selectively stimulating a third nerve branch via an adjacent second electrode of the first array. 
     As shown at  2040  in  FIG. 22F , in some examples method  2000  may further comprise arranging the second array to comprise at least three electrodes, including the at least two outer electrodes, arranged axially along the first orientation and further comprising arranging an inner electrode axially between the at least two outer electrodes. In some such examples, the method  2000  further comprises arranging the inner electrode of the second array to also define one of the electrodes of the first array. 
       FIG. 22G  is flow diagram schematically representing an example method  2100  of selective stimulation. As shown in  FIG. 22G , in some examples method  2100  comprises arranging at least one array of first electrodes to extend axially on a cuff body in a first orientation along a length of a nerve (at  2110 ) and arranging a second array of second electrodes to extend circumferentially on the cuff body in a second orientation generally perpendicular to the first orientation (at  2120 ). 
     In some examples method  2100  may further comprise arranging the first electrodes to include an inner electrode and two outer electrodes on opposite ends of the inner electrode. In some such examples, one of the first electrodes selectively functions as one of the second electrodes. In some such examples, the three electrodes may be equally spaced apart. 
     As shown at  2140  in  FIG. 22H , in some examples method  2100  may further comprise selectively stimulating at least a first nerve branch via selectively activating at least one second electrode in combination with selective activation with at least some of the first electrodes. In some such examples, the method  2100  at  2140  may comprise performing the selective activation via at least two second electrodes. 
     In some such examples, the method  2100  at  2110 ,  2120  may comprise selectively stimulating at least a first nerve branch via selectively activating at least some of the second electrodes without activating the first electrodes. 
     As shown at  2150  in  FIG. 22I , in some examples method  2100  may further comprise arranging the cuff body to include an inner axial portion and two outer axial portions on opposite ends of the inner axial portion. In some such examples method  2100  may further comprise arranging the cuff body such that each respective axial portion includes an inner circumferential portion and two outer circumferential portions on opposite ends of the inner circumferential portion, as shown at  2155  in  FIG. 22J . 
     Moreover, in some such examples, as shown at  2160  in  FIG. 22K , method  2100  may further comprise arranging the outer circumferential portions to be shaped, and biased for releasable engagement of the outer circumferential portions relative to each other to define a reclosable lumen to encircle a nerve. In some such examples, method  2100  may comprise arranging the cuff body to form at least a 270 degree circumferential structure, which extends a full length of the cuff body. In some such examples, the cuff body may form an at least 360 degree circumferential structure. 
     With further reference to at least box  2150  in  FIG. 22I , as shown at  2170  in  FIG. 22L , method  2100  may further comprise arranging a respective one of the first electrodes to be in each of the respective inner and outer axial portions. As shown at  2175  in  FIG. 22M , in some such examples method  2100  may further comprise arranging the outer circumferential portions of each respective outer axial portion of the cuff body to be electrode-free. Moreover, in some such examples (such as at at least  2175 ), method  2100  may further comprise arranging the second electrodes to be located in at least one of the respective outer circumferential portions of the inner axial portion of the cuff body, as shown at  2180  in  FIG. 22N . 
     In some such examples (such as at at least  2180 ), method  2100  may further comprise arranging the second electrodes comprises arranging two second electrodes on one outer circumferential portion of the inner axial portion, as shown at  2185  in  FIG. 22O . In some such examples (such as at at least  2185 ), method  2100  may further comprise arranging the other respective outer circumferential portion to be electrode-free, as shown at  2190  in  FIG. 22P . In some such examples (such as at at least  2190 ), method  2100  may further comprise arranging a stimulation signal vector to include one second electrode in an outer circumferential portion of the inner axial portion and the outer first electrode in each respective outer axial portion of the cuff body, as shown at  2195  in  FIG. 22Q . 
     In some examples in which the second electrodes are to be located in at least one of the respective outer circumferential portions of the inner axial portion of the cuff body, some examples of method  2100  may further comprise arranging at least three second electrodes on one outer circumferential portion of the inner axial portion, as shown at  2200  in  FIG. 22R . In some such examples, method  2100  may further comprise arranging the one outer circumferential portion to include at least one increased thickness portion to house the second electrode(s) and expose a portion of the second electrode within the lumen defined by the cuff body, as shown at  2210  in  FIG. 22S . 
     In some such examples (such as at at least  2210 ), method  2100  may further comprise arranging the two second electrodes and an inner axial electrode to be equally spaced apart circumferentially, in the second orientation, about the contact surface of cuff body, as shown at  2220  in  FIG. 22T . In some such examples (such as at  2220 ), method  2100  may further comprise arranging the at least one increased thickness portion to be oriented inwardly toward the nerve (e.g.  FIGS. 14A, 14B , other). In some such examples (such as at  2220 ), method  2100  may further comprise arranging the at least one increased thickness portion to be oriented outwardly away from the nerve (e.g.  FIGS. 18A, 18B , other). 
     With further reference to at least box  2150  in  FIG. 22I , method  2100  may further comprise arranging one second electrode to be located on one outer circumferential portion in the inner axial portion of the cuff body and the other second electrode on the other respective outer circumferential portion in the inner axial portion of the cuff body, as shown at  2230  in  FIG. 22U . 
     In some examples, the example method(s) (e.g.  2100 , etc.) described in association with  FIGS. 22G-22U  may be implemented via at least some of substantially the same features and attributes as any one of (or a combination of) the devices, cuff electrodes, cuff bodies, electrode configurations, arrangements, methods, etc. as described in association with at least  FIGS. 1-22F and/or 24-29B . 
       FIGS. 23-28  relate to several example cuff electrodes and/or associated methods including a distal extension for applying selective stimulation to at least some example nerve branch configurations. With this in mind,  FIG. 23  is a diagram  3000  schematically representing an example nerve branch configuration  3010  at which an example cuff electrode may be mounted, such as at least some of the example cuff electrodes described in association with at least  FIGS. 24-27 . As shown in  FIG. 23 , nerve branch configuration  3010  comprises a main nerve  3011  from which various branches may diverge as the main nerve  3011  progresses distally. In some examples, nerve branch configuration  3010  may comprise a main branch  3020  (e.g. a protrusor branch) and one or more side branches, such as branch  3024  and/or branch  3032 . In the particular example configuration  3010  shown in  FIG. 23 , branch  3024  corresponds to a retractor-related branch, which innervates a muscle to cause retraction of the tongue and branch  3022  causes neither protrusion nor retraction of the tongue, but may cause some deviation ( 3032 ) of the tongue from a resting position. As further shown in  FIG. 23 , branch  3024  and main branch  3020  may form a junction  3042  while branch  3020  and branch  3022  may form a junction  3044 . 
     In examples in which one may desire to stimulate solely the main branch  3020 , one desired placement of a cuff electrode (as represented by arrow  3040 ) may be distal of the dashed line  3050  such that the cuff electrode may solely engage the main branch  3020 . However, in many instances, such a placement is not feasible because of the close proximity of the diverging branches  3032 ,  3024 , surrounding non-nerve structures, etc. Accordingly, in some instances, at least one of the example cuff electrodes described below may enable securing the cuff electrode at site A ( 3052 ) while still positioning a distal extension of the cuff electrode in a position adjacent the main branch  3020  to stimulate solely (or primarily) the main branch  3020  to cause protrusion of the tongue without otherwise stimulating other deviation-causing nerve branches  3022 ,  3024 . 
     It will be understood that the example nerve configuration shown in  FIG. 23  is just one example and that other nerve configurations may be present, with the example devices and methods in  FIGS. 24-27  being applicable for at least some alternate nerve configurations. 
       FIG. 24  is a diagram  4000  schematically representing an example cuff electrode  4100  including a distal extension  4150  engaged relative to an example nerve branch configuration  4010 . In some examples, example nerve branch configuration  4010  may comprise at least some of substantially the same features and attributes as example nerve branch configuration  3010  in  FIG. 23 . 
     In some examples, at least the cuff body  4101  (and cuff electrode generally) comprises at least some of substantially the same features and attributes of the cuff electrodes as previously described in association with  FIGS. 1-18B . 
     As shown in  FIG. 24 , example implantable lead assembly  4060  includes an example cuff electrode  4100  releasably engaged about a main nerve  4010  in which the cuff electrode  4100  encircles the sides  4011 A,  4011 B of nerve  4010  and a spine  4120  of the cuff body  4101  extends generally parallel to the nerve  4010 . The cuff body  4101  includes a main body extending between a proximal end  4112 B and a distal end  4112 A, with a distal extension  4150  extending distally from distal end  4112 A. The distal extension  4150  may be formed of the same or similar material as cuff body  4101  in some examples, and comprises opposite sides  4152 A,  4152 B with distal end  4154 . In some such examples, cuff electrode  4100  may extend from lead  4070  or other lead. 
     As further shown in  FIG. 24 , in some examples cuff electrode  4100  comprises an electrode array  4200  including multiple electrodes  4222 ,  4224 ,  4226 . It will be understood that array  4200  may include a greater number or fewer number of electrodes than shown in  FIG. 24 , which may be distributed in patterns other than shown in  FIG. 24 . In the example shown in  FIG. 24 , one electrode  4222  may be located at or near a distal end  4112 A of the main cuff body  4101  while the other two electrodes  4224 ,  4226  may be located on distal extension  4150 , such as near distal end  4154 . In the example array  4200  shown, the electrodes  4224  and  4226  are spaced apart laterally from each other such that one electrode  4224  is locatable adjacent first nerve branch  4020  and the other electrode  4226  is locatable adjacent second nerve branch  4022 . In some examples, the first nerve branch  4020  corresponds to a nerve to be targeted for stimulation while the second nerve branch  4022  corresponds to a nerve branch to be excluded from stimulation, or at least not targeted for stimulation. In some examples, by utilizing a stimulation vector (V) between electrodes  4222  and  4224 , the first nerve branch  4020  can be captured and stimulated while excluding stimulation of second nerve branch  4022 . In some examples, the first nerve branch  4020  may correspond to a tongue protrusor nerve branch and the second nerve branch  4022  may correspond to a tongue retractor nerve branch or other nerve branch. 
     Among other features, via this electrode configuration distributed on the distal body extension  4150  and the main cuff body  4101 , a specific nerve branch may be targeted for selective stimulation while still securing the cuff electrode  4100  in general on a main nerve  4010  proximal to the junction  4023  between the respective first and second nerve branches  4020 ,  4022 . This avoids the complication of attempting to secure cuff body  4101  solely about first nerve branch  4020  and simplifies number and position of electrodes  4224 ,  4222  used to implement such stimulation. 
     In some examples, the main cuff body  4101  may omit any other electrodes besides electrode  4222 . In some such examples, the main cuff body  4101  primarily acts to secure the cuff  4100  relative to the nerve while the distal extension  4150  carrying electrodes  4224 ,  4226  primarily acts as the active electrode portion of the cuff electrode  4100 . 
     However, in some examples, in addition to the electrode  4222  (and the electrodes  4224 ,  4226  on distal extension  4150 ), the main cuff body  4101  may comprise at least some of substantially the same features and attributes of any one (or a combination of) of the example electrode configurations previously described in association with at least  FIGS. 1-18B . In some such examples, at least some electrodes of the electrode array  4200  (of distal extension  4150 ) may be activated in a complementary manner with other electrodes of the main cuff body  4101 . 
     As further illustrated in association with  FIGS. 25-27 , at least some more specific or alternate examples of a distal extension of an example cuff electrode  4100  may be positionable to be adjacent a nerve branch (e.g.  4020 ,  4022 ) without encircling the nerve branch (e.g.  FIG. 25 ) and/or may be positionable to at least partially wrap about (e.g. encircle) the nerve branch (e.g.  FIGS. 26, 27 ). 
     As apparent from the foregoing description associated with  FIG. 24 , it will be understood that  FIG. 24  also may be viewed as schematically representing at least an example method of neurostimulation and/or therapy for treating sleep disordered breathing, such as but not limited to obstructive sleep apnea. In some examples, this arrangement and/or method may be employed other for treating bodily conditions and/or for other nerve structures. 
       FIG. 25  is a diagram  4500  schematically representing an example cuff electrode  4560  including a distal extension  4650 , which in some examples may comprise at least some of substantially the same features and attributes as example cuff electrode  4100  including distal extension  4150  and/or the associated method of neurostimulation and/or therapy. As shown in  FIG. 25 , the cuff electrode  4560  comprises a main cuff portion  4600 . In some examples, the main cuff portion  4600  comprises at least some of substantially the same features and attributes as the cuff body  101  (e.g., at least  FIGS. 1-4 ), where similar reference numerals may refer to similar elements. For instance, main cuff portion  4600  may comprise opposing arms  4634 ,  4650  (like  134 ,  150 ) which are shaped and biased to define a lumen  4640  (like lumen  140 ) and which have ends in releasably contact at point  4609 . The main cuff portion  4600  extends between a proximal end  4607  and distal end  4608 . The main cuff body  4601  comprises and/or is supported by a base (e.g.  120  in  FIG. 1 ), which in turn is supported by an elongate, resilient lead (not shown in  FIG. 26 ). 
     As further shown in  FIG. 25 , distal extension  4650  extends from distal end  4608  of main cuff body  4601 . In some examples, distal extension  4650  comprises an elongate generally rectangular element having a proximal end  4651 A and opposite distal end  4651 B, and opposite sides  4652 A,  4652 B. 
     The distal extension  4650  carries an array  4680  of electrodes  4682 ,  4684 ,  4686 , which are distributed about a surface of the distal extension  4650 . Via such configurations, one electrode  4684  may be at a distal end  4615 B, while another electrode (e.g.  4682  or  4686 ) may be spaced proximally therefrom. In some examples, at least a pair of electrodes  4682 ,  4686  may be spaced apart laterally, such as being on or near opposite sides  4652 A,  4652 B of the distal extension  4650 . Via at least some such example configurations, a given electrode may be locatable adjacent a target nerve branch or a non-target nerve branch (e.g. a branch to be excluded from stimulation or at which stimulation is inhibited). In some examples, just one electrode is carried on the distal extension  4650 . 
     It will be understood that size, shape, and/or pattern of electrodes  4682 ,  4684 ,  4686  in  FIG. 25  is merely one example, and that the electrodes  4682 ,  4684 ,  4686  may have different sizes, shape, and/or patterns than shown in  FIG. 26 . In addition, in some examples, the array  4680  may comprise a greater number or a fewer number of electrodes than shown in  FIG. 25 . Moreover, in some examples, the electrodes (e.g.  4682 ,  4684 ,  4686 ) on distal extension  4650  may comprise all of the electrodes for the entire cuff electrode  4560 . 
     However, in some examples, the main cuff portion  4600  may comprise at least one electrode at its distal end  4608 , similar to electrode  4222  in electrode array  4200  as shown in  FIG. 24 . Moreover, in some examples, the main cuff portion  4600  may comprise several electrodes, some of which may correspond to one of the example electrode configurations previously described in association with at least  FIGS. 1-18B . 
       FIG. 26  is a diagram schematically representing an example cuff electrode  4800  including a distal extension  4850 . In some examples, the cuff electrode  4800  may comprise at least some of substantially the same features and attributes as example cuff electrode  4100  including distal extension  4150  ( FIG. 24 ) and/or main cuff portion  4600  ( FIG. 25 ) and/or the associated method of neurostimulation and/or therapy. In some examples, example cuff electrode  4800  may comprise at least some of substantially the same features and attributes as example cuff electrode  4560  ( FIG. 25 ), except having a distal extension  4850  having a different shape, size, etc. than distal extension  4650  in  FIG. 25 . As shown in  FIG. 26 , distal extension  4850  may comprise a helical coil body  4852  made of a resilient material biased to be at least partially self-wrappable about a first nerve branch (e.g.  4020  or  4022 ), without encircling the main nerve from which the first nerve branch extends. 
     The distal extension  4850  comprises a distal end  4851 B and an opposite proximal end  4851 A, which extends from the distal end  4608  of the main cuff portion  4600 . An array  4880  of electrodes  4882 ,  4884 ,  4886  is distributed along various portions of the helical coil body  4852 . As noted above, the electrodes  4882 ,  4884 ,  4886  may have a size, shape, position, and/or pattern different from shown in  FIG. 26 , and a greater number or fewer number of electrodes may comprise the array  4880 . 
     In some examples, at least one of the electrodes  4882 ,  4884 ,  4886  is positioned on the coil body  4852  to be locatable adjacent a first nerve branch (e.g.  4020 ) targeted for stimulation. In some examples, at least one of the other/remaining electrodes  4882 ,  4884 ,  4886  is positioned on the helical coil body  4852  to be locatable adjacent a second nerve branch (e.g.  4022 ) to inhibit stimulation of the second nerve branch (e.g. via hyperpolarization). In some examples, the two different branches may be selective stimulated via some combination of the electrodes  4882 ,  4884 ,  4886  with or without inclusion of at least one electrode from main cuff portion  4600 . With this in mind, in some examples the main cuff portion  4600  may omit electrodes while in some examples the main cuff portion  4600  may include at least some electrodes for stimulation, such as but not limited to any one of (or a combination of) the electrode configurations previously described in association with at least  FIGS. 1-18B . 
       FIG. 27  is a diagram  5000  schematically representing an example cuff electrode  5010  including a distal extension  5050 . In some examples, the cuff electrode  5010  may comprise at least some of substantially the same features and attributes as example cuff electrode  4100  including distal extension  4150  ( FIG. 24 ) and/or the associated method of neurostimulation and/or therapy, and/or as example main cuff portion  4600  ( FIG. 25 ). In some examples, cuff electrode  5010  may comprise at least some of substantially the same features and attributes as example cuff electrode  4560  ( FIG. 25 ), except having a distal extension  5050  having a different shape, size, etc. than distal extension  4650  in  FIG. 25 . As shown in  FIG. 27 , distal extension  5050  may comprise a cylindrically-shaped body  5052  made of a resilient material biased to be at least partially self-wrappable about a nerve branch, such as first or second nerve branch  4020  or  4022 , without encircling the main nerve from which the first nerve branch extends. In one aspect, body  5052  defines a lumen (as represented via dashed lines  5053 ) through one of the nerve branches (e.g.  4020 ,  4022 ) may extend. 
     The distal extension  5050  comprises a distal end  5051 B and an opposite proximal end  5051 A, which extends from the distal end  4608  of the main cuff portion  4600 . The body  5052  may comprise a cuff body like main cuff body  4601  or another type of cuff body having arms or other elements biased to selectively wrap about a nerve branch. In some examples, an interior surface of the body  5052  (e.g. lumen  5053 ) may carry an array of electrodes distributed along various portions of the coil body  5052  such that at least one of such electrodes may be locatable adjacent a first nerve branch (e.g.  4020 ) targeted for stimulation. The array of electrodes may be arranged in a pattern as shown in  FIG. 24, 25 , or  26  or may be arranged in a different pattern. 
     In some examples, at least one other/remaining electrodes may be positioned on an exterior of body  5052  to be locatable adjacent a second nerve branch (e.g.  4022 ) to stimulate or to inhibit stimulation of the second nerve branch. In some examples, the two different branches (e.g.  4020 ,  4022 ) may be selectively stimulated via some combination of the electrodes of distal extension  5050  with or without inclusion of at least one electrode from main cuff portion  4600 . With this in mind, in some examples the main cuff portion  4600  may omit electrodes while in some examples the main cuff portion  4600  may include at least some electrodes for stimulation, such as but not limited to any one of (or a combination of) the electrode configurations previously described in association with at least  FIGS. 1-18B . 
       FIG. 28A  is flow diagram schematically representing an example method  5500  of selective stimulation. As shown in  FIG. 28A , in some examples method  5500  comprises arranging at least two electrodes spaced apart on a distal extension, which extends from a main cuff body (at  5510 ), encircling a main nerve with the main cuff body while positioning the distal extension to be located adjacent a first nerve branch (of the main nerve) apart from other diverging nerve branches (at  5512 ), and selectively stimulating the first nerve branch via at least one of the two electrodes of the distal extension in combination with another electrode (at  5514 ). 
     As shown at  5530  in  FIG. 28B , method  5500  may further comprise performing the selective stimulation in combination with another electrode supported by the distal extension and/or the main cuff body. In some examples, the distal extension may carry just one electrode. 
     In some examples, method  5500  may be implemented via at least some of substantially the same features and attributes as any one of (or a combination of) the devices, cuff electrodes, cuff bodies, electrode configurations, etc. as described in association with at least  FIGS. 24-27  and/or  FIGS. 1-22 . 
     As shown at  5535  in  FIG. 28C , in some examples method  5500  may further comprise utilizing at least some electrodes of a main cuff body to stimulate a main nerve in a complementary manner with stimulating a particular nerve branch via at least one of the electrodes of the distal extension. 
     However, in some examples the electrodes of the main cuff body do not contribute to stimulating the main nerve and/or the main cuff body omits any electrodes (i.e. the main cuff body is electrode-free). Accordingly, in some such examples the main cuff body may primarily act to secure the overall cuff electrode relative to the main nerve, also thereby at least partially securing or supporting the distal extension relative to nerve branches distal to the main cuff body (and the main nerve). 
     In some examples, the main cuff body may comprise at least one electrode at its distal end (e.g.  4608  such as in  FIG. 24 ) to enable stimulation in cooperation with at least one electrode on a distal extension from the main cuff body. 
     As shown at  5540  in  FIG. 28D , in some examples method  5500  may further comprise arranging the distal extension to be at least partially self-wrappable about the first nerve branch without encircling the main nerve. In some such examples, the method may comprise arranging the distal extension as at least one of a helical coil body (e.g.  FIG. 26 ) and a cylindrically-shaped body (e.g.  FIG. 27 ). 
     As shown at  5550  in  FIG. 28E , in some examples method  5500  may further comprise arranging the distal extension to extend along a portion of the first nerve branch without at least partially wrapping about the first nerve branch. In some such examples, method  5500  may further comprise arranging the distal extension as an elongate rectangular element (e.g.  FIG. 24 or 25 ). 
     As shown at  5610  in  FIG. 29A , in some examples method  5500  may be implemented as a method  5600  comprising arranging a single first electrode on a distal extension, which extends from a main cuff body. At  5615 , method  5600  comprises encircling a main nerve with the main cuff body while positioning the distal extension to be located adjacent a first nerve branch of a main nerve. As shown at  5620 , method  5600  comprises selectively stimulating the first nerve branch solely via the single first electrode of the distal extension in association with at least a second electrode. As shown at  5640  in  FIG. 29B , in some examples method  5600  may further comprise arranging the second electrode to be on the main cuff body. In one aspect, in some such examples the first nerve branch extends separately and distally from proximal portions of the main nerve in which the first nerve branch is enclosed within the main nerve. 
     Although specific examples have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein.