Abstract:
An implantable stimulation lead has electrode contacts that are configured to deliver an electrical stimulation therapy for a patient. A sheath extends along a longitudinal axis. The sheath defines a lumen into which the stimulation lead can be inserted. A distal end of the sheath includes a plurality of base segments that are separated from one another. A plurality of fixation structures are located on the base segments, respectively. In a first configuration, the fixation structures are each disposed proximate to the sheath. In a second configuration, the fixation structures each extend radially outward from the sheath. In a third configuration, the base segments deflect radially inward toward the longitudinal axis.

Description:
FIELD OF THE INVENTION 
       [0001]    This is a continuation of U.S. application Ser. No. 14/537,051, filed Nov. 10, 2014, which claims benefit of U.S. application Ser. No. 61/923,927, filed Jan. 6, 2014 and U.S. application Ser. No. 61/901,499, filed Nov. 8, 2013. This disclosure is directed to a patient programmer for controlling an electrical stimulation implantable device. 
       BACKGROUND 
       [0002]    Stimulation of various nerves and tissue has been found to be a promising treatment for various conditions and/or ailments. For instance, pain, urinary urge, fecal incontinence, and epilepsy, to name a few, are indications for various nerve/tissue stimulation therapies. Various nerves and tissue are commonly targeted for stimulation therapy, including, but not limited to the sacral nerve, the pudendal nerve, the vagus nerve, the tibial nerve, and the spinal cord, to name a few. 
         [0003]    Leads used for nerve and/or tissue stimulation often include tines for anchoring the lead within the patient. Leads with integral tines or other fixation members can be difficult to extract, should the need arise, due to the retention force that the tines or other fixation members offer. Sometimes, the retention force is so high that the physician can break the lead when pulling on it. This presents problems in that the portion of the lead, if it were to remain in the patient, could present health risks. However, if the physician tries to remove the portion of the lead, that too could present health risks in trying to access the portion of the lead and pull it out or surgically extract it. As such, while tines or other fixation members mitigate lead migration during use, they also present issues during extraction of the lead. 
       SUMMARY 
       [0004]    This overview is intended to provide an overview of subject matter of the present patent document. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent document. 
         [0005]    The present inventors have recognized, among other things, that the present subject matter can be used to provide an implantable stimulation lead including a selectively collapsible fixation member in order to decrease removal force for removing the stimulation lead from within a patient. To better illustrate the apparatuses, systems, and methods described herein, a non-limiting list of examples is provided here: 
         [0006]    Example 1 can include subject matter that can include a stimulation lead for at least partial implantation within a patient. The stimulation lead includes an elongate lead body including a distal end and a proximal end. A sheath is selectively attachable to the lead body and includes a longitudinal sheath axis. A lumen extends from a proximal sheath end to a distal sheath end. A fixation member is disposed on the sheath. With the sheath attached to the lead body, the lead body is disposed at least partially within the lumen of the sheath, and the lead body and the sheath are substantially coaxial. The fixation member includes a retracted configuration in which the fixation member is disposed proximate the sheath. A deployed configuration includes the fixation member extending radially outwardly from the sheath to anchor the stimulation lead within the patient. A removal configuration includes the fixation member radially inwardly collapsible toward the longitudinal sheath axis with the lead body removed from within the sheath. 
         [0007]    In Example 2, the subject matter of Example 1 is optionally configured such that the sheath includes a plurality of fixation members. 
         [0008]    In Example 3, the subject matter of any one of Examples 1-2 is optionally configured such that the fixation member is disposed proximate the distal sheath end. 
         [0009]    In Example 4, the subject matter of any one of Examples 1-3 is optionally configured such that the sheath is compressively attachable to the lead body. 
         [0010]    In Example 5, the subject matter of Example 4 is optionally configured such that the sheath includes a suture disposed around the sheath, wherein tightening of the suture compressively engages the sheath to the lead body. 
         [0011]    In Example 6, the subject matter of any one of Examples 1-5 is optionally configured such that the sheath includes a suture groove for retaining a suture within the suture groove, wherein tightening of the suture compressively engages the sheath to the lead body. 
         [0012]    In Example 7, the subject matter of Example 6 is optionally configured such that the suture groove is disposed around the sheath proximate a proximal end of the sheath. 
         [0013]    In Example 8, the subject matter of any one of Examples 6-7 is optionally configured such that the sheath includes a radiopaque marker proximate the suture groove. 
         [0014]    In Example 9, the subject matter of any one of Examples 1-8 is optionally configured such that the fixation member includes a tine. 
         [0015]    In Example 10, the subject matter of any one of Examples 1-9 is optionally configured such that the fixation member is retained within the retracted configuration with the fixation member disposed within an introducer. 
         [0016]    In Example 11, the subject matter of any one of Examples 1-10 is optionally configured such that the fixation member is retained in the deployed configuration with the lead body disposed within the lumen and extending from the distal end of the sheath. 
         [0017]    In Example 12, the subject matter of any one of Examples 1-11 is optionally configured such that the fixation member is biased to the deployed configuration. 
         [0018]    In Example 13, the subject matter of any one of Examples 1-12 is optionally configured such that the sheath includes a base on which the fixation structure is disposed, the base being deflectable with respect to the remainder of the sheath. With the lead body disposed within the sheath, the base is inhibited from deflecting. With the lead body removed from within the sheath, the base is able to deflect radially inwardly toward the longitudinal sheath axis to allow the fixation member to be radially inwardly collapsible in the removal configuration. 
         [0019]    Example 14 can include, or can optionally be combined with any one of Examples 1-13 to include subject matter that can include an apparatus for at least partial implantation within a patient. The apparatus includes a sheath selectively attachable to the lead body. The sheath includes a longitudinal sheath axis. A lumen extends from a proximal sheath end to a distal sheath end. At least one fixation member disposed on the sheath. An elongate lead body includes a distal end and a proximal end. The lead body is sized and shaped to fit within the lumen of the sheath. With the lead body disposed within the sheath, the lead body and the sheath are substantially coaxial. The at least one fixation member includes a retracted configuration in which the at least one fixation member is disposed proximate the sheath. A deployed configuration includes the at least one fixation member extending radially outwardly from the sheath to anchor the apparatus within the patient. A removal configuration includes the at least one fixation member radially inwardly collapsible toward the longitudinal sheath axis with the lead body removed from within the sheath. 
         [0020]    In Example 15, the subject matter of Example 14 is optionally configured such that the at least one fixation member is disposed proximate a distal end of the sheath. 
         [0021]    In Example 16, the subject matter of any one of Examples 14-15 is optionally configured such that the sheath is compressively attachable to the lead body, 
         [0022]    In Example 17, the subject matter of Example 16 optionally includes a suture disposed around the sheath within a suture groove proximate a proximal end of the sheath, wherein tightening of the suture compressively engages the sheath to the lead body. 
         [0023]    In Example 18, the subject matter of any one of Examples 14-17 optionally includes an introducer removably disposed around the sheath and the at least one fixation member of the sheath. The at least one fixation member is retained within the retracted configuration with the at least one fixation member disposed within the introducer. Removal of the sheath from within the introducer allows the at least one fixation member to move to the deployed configuration. 
         [0024]    In Example 19, the subject matter of any one of Examples 14-18 is optionally configured such that the at least one fixation member is biased to the deployed configuration. 
         [0025]    In Example 20, the subject matter of any one of Examples 14-19 is optionally configured such that the sheath includes a base on which the at least one fixation structure is disposed. The base is deflectable with respect to the remainder of the sheath. With the lead body disposed within the sheath, the base is inhibited from deflecting. With the lead body removed from within the sheath, the base is able to deflect radially inwardly toward the longitudinal sheath axis to allow the at least one fixation member to be radially inwardly collapsible in the removal configuration. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  shows a system for introducing a stimulation lead apparatus with collapsible fixation members in accordance with at least one example of the invention. 
           [0027]      FIG. 2  shows an enlarged view of a distal end of the system of  FIG. 1 . 
           [0028]      FIG. 3  shows the distal end of the system of  FIG. 1  with an obturator removed from within a sheath of the stimulation lead apparatus, the sheath including fixation members in a retracted configuration. 
           [0029]      FIG. 4  shows the sheath of  FIG. 3  with the introducer moved proximally with respect to the sheath, the sheath including fixation members in a deployed configuration. 
           [0030]      FIG. 5  shows the sheath of  FIG. 3 , the sheath including fixation members in a deployed configuration. 
           [0031]      FIG. 6  shows a stimulation lead apparatus with collapsible fixation members in accordance with at least one example of the invention. 
           [0032]      FIG. 7  shows an enlarged view of a distal end of the stimulation lead apparatus of  FIG. 6 . 
           [0033]      FIG. 8  shows a distal end of a sheath of the stimulation lead apparatus of  FIG. 6 , the sheath including fixation members during removal of the sheath. 
           [0034]      FIG. 9  shows a sheath of a stimulation lead apparatus in accordance with at least one example of the invention, the sheath including fixation members in a deployed configuration. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    The present patent document relates to apparatuses, systems, and methods for anchoring an implantable device within a patient. In some examples, the apparatuses, systems, and methods described herein relate to a stimulation lead. In some examples, the apparatuses, systems, and methods described herein relate to a stimulation lead including a collapsible fixation member. 
         [0036]    The present inventors have recognized, among other things, that it is desirable to provide an implantable stimulation lead including a selectively collapsible fixation member in order to decrease removal force for removing the stimulation lead from within a patient. By decreasing the removal force, the present inventors have recognized, among other things, that, in some examples, fewer leads will break during removal procedures, potentially leading to decreased complications and cost associated with removal procedures. While primarily described with respect to stimulation leads, it should be understood, however, that the subject matter described herein can be used with other apparatuses, such as, but not limited to implantable medical devices. 
         [0037]    Referring to  FIGS. 1-9 , in some examples, the apparatuses, devices, systems, and methods described herein can include a stimulation lead including one or more fixation members that can collapse during extraction. In this way, removal force can be decreased from that of conventional leads having deployed tines or other fixation structures. 
         [0038]    Referring to  FIGS. 6 and 7 , in some embodiments, a stimulation lead  100  for at least partial implantation within a patient. In some examples, the stimulation lead  100  is configured to stimulate a nerve or other tissue of the patient. In further examples, the stimulation lead  100  is configured to stimulate one or more nerves including, but not limited to a sacral nerve and/or a pudendal nerve of the patient. 
         [0039]    In some examples, the stimulation lead  100  includes an elongate lead body  120  including a distal end  122  and a proximal end  124 . In some examples, the lead body  120  includes a longitudinal lead axis  121 . The lead body  120 , in some examples, includes one or more electrodes  130  for stimulating tissue. In some examples, the one or more electrodes  130  are disposed proximate the distal end of the lead body  120 . In some examples, the lead body  120  includes four electrodes  130 . However, it should be understood that, in other examples, the lead body includes more or fewer than four electrodes depending upon the anatomy of the patient and/or the particular nerve or other tissue that is intended to be stimulated using the stimulation lead. The one or more contacts  136 , in some examples, are equal in number to the total number of electrodes  130  on the stimulation lead  100 . In some examples, the stimulation lead  100  includes conductors running between the one or more contacts  136  and the corresponding one or more electrodes  130  to electrically couple the one or more electrodes  130  to the one or more contacts  136 . In some examples, the lead body  120  includes one or more contacts  136  configured to electrically couple to a pulse generator or other medical device or a lead extension. In some examples, the one or more contacts  136  are configured to electrically couple the one or more electrodes  130  to the pulse generator to transmit electrical stimulation pulses generated by the pulse generator to the appropriate one or more electrodes  130  and, in turn, to the appropriate one or more target nerves and/or target tissues. 
         [0040]    Referring now to  FIGS. 5-7 , in some examples, the stimulation lead  100  includes a sheath  140  selectively attachable to the lead body  120 . In some examples, the sheath  140  includes a longitudinal sheath axis  141 . The sheath  140  includes, in some examples, a lumen  146  extending from a proximal sheath end  144  to a distal sheath end  142 . In some examples, the lumen  146  is sized and shaped to accept at least a portion of the lead body  120  within the lumen  146 . In some examples, the sheath  140  includes at least one fixation member  150  disposed on the sheath  140 . In some examples, the at least one fixation member  150  is configured to at least partially anchor the stimulation lead  100  within the patient. In some examples, the sheath  140  includes a plurality of fixation members  150 . In the example shown in  FIGS. 5-7 , the sheath  140  includes four fixation members  150 . In other examples, it is contemplated that the sheath include more or less than four fixation members, provided that the number of fixation members is sufficient to at least partially anchor the stimulation lead within the patient. In some examples, the at least one fixation member  150  is disposed proximate the distal sheath end  142 . In some examples, the at least one fixation member  150  includes a tine  154 . In other examples, the at least one fixation member  150  includes other fixation members, such as fins, barbs, coils, or the like. It is noted that, in various examples, different numbers, sizes, and/or types of fixation structures can be used with the stimulation lead  100 , for instance to adjust or tune fixation of the stimulation lead  100  within the patient. In some examples, the at least one fixation member  150  provides main anchoring (major fixation) of the stimulation lead  100 . 
         [0041]    In some examples, the sheath  140  is selectively attachable to the lead body  120 . That is, in some examples, the sheath  140  can be substantially fixed with respect to the lead body  120 . In this way, in some examples, the sheath  140  can be attached to the lead body  120  when the lead body  120  is in a desired location with respect to the patient to allow the at least one fixation member  150  to at least partially anchor the lead body  120  and, in turn, the stimulation lead  100 , in place with respect to the patient. In some examples, the sheath  140  is compressively attachable to the lead body  120 . In some examples, the sheath  140  includes a suture  149  disposed around the sheath  140 , wherein tightening of the suture  149  compressively engages the sheath  140  to the lead body  120 . In some examples, the sheath  140  includes a suture groove  148  for retaining the suture  149  within the suture groove  148 . In some examples, the suture groove  148  inhibits the suture  149  from migrating along the sheath  140  and/or the lead body  120 , for instance, during implantation, which could potentially lead to migration and/or dislodgement of the lead body  120 . In some examples, the suture groove  148  is disposed around the sheath  140  proximate a proximal end  144  of the sheath  140 . In other examples, the suture groove  148  is disposed around the sheath  140  at a location other than proximate the proximal end  144  of the sheath  140 . in some examples, the sheath  140  includes a radiopaque marker  147  proximate the suture groove  148 . In various examples, the suture groove  148  or other suture location (or the suture  149  itself) can be marked with a band or other marker including various materials, including, but not limited to barium sulfate, platinum iridium, tungsten, etc. In some examples, the radiopaque marker  147  facilitates a physician or other caregiver in finding the suture  149  (for instance, using fluoroscopy) while the stimulation lead  100  is implanted within the patient, for instance, in order to remove the suture  149  for removal of the lead body  120  and/or the sheath  140  from within the patient, as is described herein. In some examples, the suture  149  and/or suture groove  148  includes material to make the suture  149  and/or suture groove  148  imageable in other imagining modalities in addition to or instead of fluoroscopy, including, but not limited to, one or more of magnetic resonance imaging, computed tomography scanning, ultrasound imaging, or the like. In some examples, the suture groove  148  is integrally formed with the sheath  140 . In other examples, the suture groove is disposed in a separate component, such as, but not limited to, a suture sleeve. In still other examples, the sheath  140  can be selectively attached to the lead body  120  using another attachment device, such as, but not limited to, a compression or crimp sleeve, a threaded engagement between the sheath and the lead body, a staple or other fastener, or a combination thereof. 
         [0042]    In some examples, with the sheath  140  attached to the lead body  120 , the lead body  120  is disposed at least partially within the lumen  146  of the sheath  140 . In some examples, the lead body  120  and the sheath  140  are substantially coaxial with the sheath  140  attached to the lead body  120 . That is, in some examples, the longitudinal lead axis  121  and the longitudinal sheath axis  141  are substantially collinear with the sheath  140  attached to the lead body  120 . 
         [0043]    Referring now to  FIGS. 3-8 , the at least one fixation member  150  includes various configurations. In some examples, the at least one fixation member  150  includes a retracted configuration  150 A ( FIG. 3 ) in which the at least one fixation member  150  is disposed proximate the sheath  140  to inhibit the at least one fixation member  150  from engaging with tissue of the patient and anchoring the sheath  140 . In this way, in some examples, while the at least one fixation member  150  is in the retracted configuration  150 A, the sheath  140  can be moved and manipulated within the patient under the desired location of the sheath  140  is determined and achieved. 
         [0044]    In some examples, the at least one fixation member  150  includes a deployed configuration  150 B ( FIGS. 4-7 ) in which the at least one fixation member  150  extends radially outwardly from the sheath  140  to engage with the tissue of the patient in order to anchor the stimulation lead  100  within the patient. In some examples, the at least one fixation member  150  extends outwardly from the sheath  140  farther in the deployed configuration  150 B than in the retracted configuration  150 A. In examples in which the at least one fixation member  150  includes the tine  154 , the tine  154  includes a fixed end  154 A attached to the sheath  140  and a free end  154 B, the free end  154 B being spaced radially outwardly from the sheath  140  a greater distance in the deployed configuration  150 B than in the retracted configuration  150 A. In some examples, the at least one fixation member  150  is biased to the deployed configuration  150 B. 
         [0045]    In some examples, the at least one fixation member  150  includes a removal configuration  150 C ( FIG. 8 ) in which the at least one fixation member  150  is radially inwardly collapsible toward the longitudinal sheath axis  141  with the lead body  120  removed from within the sheath  140 . In some examples, the sheath  140  includes at least one base  152  on which the at least one fixation structure  150  is disposed. In some examples, the base  152  is deflectable with respect to the remainder of the sheath  140 . In some examples, the base  152  is cantilevered from the sheath  140  and deflectable along a portion proximate a fixed end  152 A of the base  152  that is connected to the sheath  140  to allow a free end  152 B of the base  152  to rotate inwardly with respect to the sheath  140  toward the longitudinal sheath axis  141 . In some examples, the at least one fixation member  150  is retained in the deployed configuration  150 B with the lead body  120  disposed within the lumen  146  and extending from the distal end  142  of the sheath  140 . With the lead body  120  disposed within the sheath  140 , in some examples, the base  152  abuts the lead body  120  and is inhibited from deflecting and allowing the at least one fixation member from moving to the removal configuration  150 C. However, in some examples, with the lead body  120  removed from within the sheath  140 , the base  152  is able to deflect radially inwardly toward the longitudinal sheath axis  141  to allow the at least one fixation member  150  to be radially&#39; inwardly collapsible in the removal configuration  150 C. That is, with the lead body  120  removed from within the sheath  140 , the at least one fixation member  150  is able to collapse into the now-open area within the sheath  140 , thereby allowing the at least one fixation member  150  to fold distally with respect to the sheath  140  with proximal movement of the sheath  140  (for instance, as would occur with a proximally directed force applied to the sheath  140  during removal of the sheath  140  from a patient). In this way, in some examples, removal of the sheath  140  from within the patient is facilitated by decreasing the amount of force for removing the sheath  140  compared to, for instance, another lead having non-collapsible tines. 
         [0046]    Referring now to  FIGS. 1-4 , one or more components can be used to implant the sheath  140 . For instance, in some examples, a tubular introducer  10  or other delivery system or apparatus can be used to retain the sheath  140  during implantation of the sheath  140 . In some examples, the introducer  10  includes an open distal end  12 , sized to allow distal exiting of the sheath  140  and/or the lead body  120  through the distal end  12 . In some examples, the introducer  10  includes a proximal handle  14  to facilitate maneuvering of the introducer, for instance during implantation of the sheath  140 . In some examples, the at least one fixation member  150  is retained within the retracted configuration  150 A with the at least one fixation member  150  disposed within the introducer  10  to facilitate implantation of the sheath  140 , for instance, by inhibiting the at least one fixation member  150  from deploying and/or otherwise engaging with tissue during implantation of the sheath  140 . In some examples, removal of the sheath  140  from within the introducer  10  allows the at least one fixation member  150  to move to the deployed configuration  150 B ( FIG. 4 ). In some examples, movement of the at least one fixation member  150  to the deployed configuration  150 B is facilitated because the at least one fixation member  150  is biased to the deployed configuration  150 B. 
         [0047]    Referring to  FIGS. 1 and 2 , in some examples, an obturator  20  can be used with the sheath  140  for implantation of the sheath  140  within the patient. In some examples, the obturator  20  includes a distal end  22  configured to extend distally beyond the distal end  12  of the introducer  10  and/or the distal end  142  of the sheath  140 . In some examples, the distal end  22  of the obturator  20  is tapered with an atraumatic tip to facilitate insertion of the obturator  20 , the sheath  140 , and the introducer  10  within the patient and inhibit tissue damage. The obturator  20  can be used within the sheath  140 , in some examples, to assist in extending the sheath  140  from the introducer  10 , maintaining the at least one fixation member  150  in position, and/or positioning the sheath  140  within the patient. In some examples, the obturator  20  includes a proximal handle  24 , for instance, to facilitate removal of the obturator  20  from within the sheath  140 . In some examples, once the sheath  140  is positioned in the desired location within the patient, the obturator  20  can be removed from within the sheath  140 , thereby allowing for the lead body  120  to be inserted into the sheath  140 . 
         [0048]    Referring to  FIG. 9 , in some examples, a sheath  240  configured differently from the sheath  140  described herein, can be used with the lead body  120  to at least partially anchor the lead body  120  within the patient. In some examples, the sheath  240  is selectively attachable to the lead body  120 . In some examples, the sheath  240  includes a longitudinal sheath axis  241 . The sheath  240  includes, in some examples, a lumen  246  extending from a proximal sheath end to a distal sheath end  242 . In some examples, the lumen  246  is sized and shaped to accept at least a portion of the lead body  120  within the lumen  246 . In some examples, the sheath  240  includes at least one fixation member  250  disposed on the sheath  240 . In some examples, the at least one fixation member  250  is configured to at least partially anchor the stimulation lead within the patient. In some examples, the sheath  240  includes a plurality of fixation members  250 . In the example shown in  FIG. 9 , the sheath  240  includes two sets of four fixation members  250 . In other examples, it is contemplated that the sheath include more or less than eight total fixation members, provided that the number of fixation members is sufficient to at least partially anchor the stimulation lead within the patient. In some examples, the at least one fixation member  250  is disposed proximate the distal sheath end  242 . In some examples, the at least one fixation member  250  includes a tine  254 . In other examples, the at least one fixation member  250  includes other fixation members, such as fins, barbs, coils, or the like. In some examples, the at least one fixation member  250  includes a deflectable base  252  on which the tine  254  or other fixation member  250  is disposed. As such, similar to the at least one fixation member  150  described herein, the at least one fixation member  250  can include a retracted configuration, a deployed configuration  250 B, and a removal configuration. It is noted that, in various examples, different numbers, sizes, and/or types of fixation structures can be used with the stimulation lead, for instance to adjust or tune fixation of the stimulation lead within the patient. In some examples, the at least one fixation member  250  provides main anchoring (major fixation) of the stimulation lead. 
         [0049]    In some examples, the sheath  240  differs from the sheath  140  described herein in that the sheath  240  includes a different configuration of fixation members  250 . For instance, in the example shown in  FIG. 9 , the sheath  240  includes two sets of four fixation members  250  disposed proximate the distal sheath end  242 . Such a configuration, in some examples, can offer different characteristics, such as, for instance, anchoring strength, than another sheath, such as, but not limited to the sheath  140  described herein. Although only the sheaths  140 ,  240  are shown and described herein, it should be understood that other configurations of sheaths and/or other configurations of fixation members are contemplated herein. For instance, in various examples, a sheath can include one or more of the following: a different numbers of fixation members, one or more fixation members disposed in a location along the sheath other than at the distal end of the sheath, one or more differently shaped fixation members, two or more fixation members disposed on a base, or the like. In this way, various sheaths can be used or chosen between in order to impart the desired one or more fixation characteristics to the stimulation lead based upon various factors including, but not limited to patient size and/or anatomy, tissue or nerve to be stimulated, or the like, 
         [0050]    Referring to  FIGS. 1-7 , in some examples, the stimulation lead  100  can be implanted within the patient. In some examples, the sheath  140  can be inserted within the introducer  10  for insertion within the patient at a desired implant site. The following description references only the sheath  140  for the sake of convenience; however, it should be understood that the physician or other caregiver can use the sheath  240  or another differently-configured sheath instead of the sheath  140 , depending upon the one or more fixation characteristics desired for the particular patient. 
         [0051]    In some examples, the obturator  20  can be inserted within the sheath  140  and the introducer  10  to facilitate insertion of the sheath  140  within the patient. In other examples, the introducer  10  can be inserted alone (or with the obturator  20 ), and, when in the desired location within the patient, the obturator  20  can be removed and the sheath  140  can be passed through the introducer  10  (or the sheath  140  can be passed over the obturator  20  if the obturator  20  is kept within the introducer  10 ). Once the sheath  140  is disposed in the desired location within the patient, the introducer  10  can be retracted (for instance, pulled proximally from) the sheath  140 , allowing the one or more fixation members  150  to move from the retracted configuration  150 A to the deployed configuration  150 B. In some examples, the lead body  120  can be placed within the lumen  146  of the sheath  140  and extended distally from the distal sheath end  142  to expose at least one of the one or more electrodes  130  of the lead body  120 . In some examples, the sheath can be retained within the introducer  10  and the one or more fixation members  150  retained in the retracted configuration  150 A and the lead body  120  can be placed within the lumen  146  of the sheath  140  and extended distally from the distal sheath end  142  to expose at least one of the one or more electrodes  130  of the lead body  120 , for instance, to perform test stimulations to aid in positioning the stimulation lead  100  before the one or more fixation members  150  are deployed and the stimulation lead  100  is anchored. 
         [0052]    Once the sheath  140  and the lead body  120  are in the desired location within the patient and the introducer  10  is removed, the sheath  140  and the lead body  120  can be engaged to one another to inhibit relative motion between the sheath  140  and the lead body  120 . In some examples, the sheath  140  and the lead body  120  can be engaged by tightening the suture  149  In some further examples, the suture  149  is disposed within the suture groove  148 . In other examples, an attachment device other than or in addition to the suture  149  can be used to engaged and inhibit relative motion between the sheath  140  and the lead body  120 . 
         [0053]    In some examples, if it is desired to extract the stimulation lead  100 , the lead body  120  can be removed from within the sheath  140 , leaving the sheath  140  empty and allowing the one or more fixation members  150  to move to the removal configuration  150 C, allowing the one or more fixation members  150  to collapse toward the longitudinal sheath axis  141  and into the now-empty lumen  146  of the sheath  140 . With the one or more fixation members  150  in the removal configuration  150 C, in some examples, the removal force to extract the sheath  140  from the patient is less than that of leads or other devices having non-collapsible tines. In some examples, the removal force for removing the sheath  140  with the one or more fixation members  150  is significantly lower than that of leads or other devices having non-collapsible tines. 
         [0054]    In some examples, if the suture  149  is holding the sheath  140  and the lead body  120  together within the patient, the suture  149  must first be removed in order to remove the lead body  120  from within the sheath  140  and ultimately remove the sheath  140  from the patient. Finding the suture location can sometimes be difficult because it is disposed within the patient. In some examples, the suture groove  148  or other location of the suture  149  (or the suture  149  itself) can be marked with the radiopaque material  147  so that it shows up in fluoroscopy (or another imaging modality) to aid the physician or other caregiver in finding the location of the suture  149 . 
         [0055]    In some examples, because the sheath  140 ,  240  and the lead body  120  are separate, different sheaths  140 ,  240  can include different fixation member configurations and the physician or other user can select the sheath configuration according to the anatomy, size, shape, etc. of the patient, the structure around where the distal lead end  122  of the lead body  120  is intended to be implanted, the type of lead body  120 , or any other factor that could result in one fixation member configuration being better or more appropriate than another configuration. In various examples, spacing of fixation members  150 , type of fixation member  150 , number of fixation members  150 , or the like can he different with different configurations. This allows the physician or other caregiver, in some examples, to select the sheath  140 ,  240  having the fixation member configuration that the physician or other caregiver wants rather than being forced to use a fixation member configuration that comes with a lead, for instance. 
         [0056]    In some examples, because the lead body  120  (and, in turn, the one or more electrodes  130  of the lead body  120 ) and the sheath  140 ,  240  are independent, spacing between the one or more fixation members  150  and the one or more electrodes  130  of the lead body  120  is variable and can be configured according to the patient and/or the physician&#39;s or other caregiver&#39;s preferences prior to the one or more fixation members  150 ,  250  being placed in the deployed configuration  150 B,  250 B and/or the sheath  140 ,  240  being affixed to the lead body  120  (for instance, with a suture). 
         [0057]    The present inventors have recognized various advantages of the subject matter described herein. For instance, in some examples, the apparatuses, systems, and methods described herein can be used to provide an implantable stimulation lead including a selectively collapsible fixation member in order to decrease removal force for removing the stimulation lead from within a patient. By decreasing the removal force, the present inventors have recognized, among other things, that, in some examples, fewer leads will break during removal procedures, potentially leading to decreased complications and cost associated with removal procedures. While various advantages of the example apparatuses, systems, and methods are listed herein, this list is not considered to be complete, as further advantages may become apparent from the description and figures presented herein. 
         [0058]    Although the subject matter of the present patent application has been described with reference to various examples, workers skilled in the art will recognize that changes can be made in form and detail without departing from the scope of the subject matter recited in the below claims. 
         [0059]    The above Detailed Description includes references to the accompanying drawings, which form a part of the Detailed Description. The drawings show, by way of illustration, specific examples in which the present apparatuses and methods can be practiced. These embodiments are also referred to herein as “examples.” 
         [0060]    The above Detailed Description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more elements thereof) can be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. Also, various features or elements can be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter can lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. 
         [0061]    In this document, the terms “a” or “an” are used to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “about” and “approximately” or similar are used to refer to an amount that is nearly, almost, or in the vicinity of being equal to a stated amount. 
         [0062]    In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, an apparatus or method that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 
         [0063]    The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.