Patent Publication Number: US-2021177479-A1

Title: System And Method For Positioning A Tracking Device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. application Ser. No. 15/886,439 filed on Feb. 1, 2018. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a device holder, and particularly to a holder to position a trackable member. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     In a selected procedure an instrument may be moved relative to a subject. The subject may include an external cover or shell portion and internal members or portions. The instrument may be operated to perform a procedure on the internal components while only minimally disturbing the outer shell. 
     In performing a procedure, therefore, an instrument may be tracked with a tracking system. The tracked position of the instrument may be displayed on a display device for viewing a determined position of the instrument. The user may view the display device to determine or understand the position of the instrument relative to the subject. It may be selected, to track more than one instrument during a selected procedure. 
     SUMMARY 
     According to various embodiments, a system for tracking an instrument is disclosed. The system includes a plurality of trackable members and a tracking member holder. The tracking member holder includes a chassis portion, an instrument guiding portion having an internal wall defining an instrument passage, a trackable member engagement portion configured to hold at least one trackable member of the plurality of trackable members relative to the chassis portion, and a handle engageable portion configured to hold the chassis portion relative to a handle. 
     A system for tracking an instrument is disclosed, according to various embodiments. The system includes a tracking member holder, including (i) a chassis portion, (ii) a trackable member engagement portion, and (iii) a handle engaging portion. The system may further include an instrument handle. In various embodiments, an instrument may also be configured to be held relative to the instrument handle and moved with the instrument handle. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a perspective view of a tracking device holder, according to various embodiments; 
         FIG. 2  is a perspective view of the tracking device holder connected to a handle, according to various embodiments; 
         FIG. 3  is a perspective view of the tracking device holder connected to a handle and an instrument passing through the tracking device holder, according to various embodiments; and 
         FIG. 4  is an environmental view of the tracking device holder, handle, and instrument, according to various embodiments. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. Although the following is disclosed regarding an exemplary surgical procedure on a human subject, it is understood that the subject disclosure and the following claims may be directed for non-human surgical procedures and non-surgical procedure. 
     With initial reference to  FIGS. 1, 2 and 3 , a holder  10  is illustrated. The holder  10  may alone, or in combination with trackable members, form a tracking device that is trackable, as discussed herein. The holder  10  may also be referred to as a tracking device holding assembly, a tracking device holder, a tracking member holder, trackable member holder, or guide assembly. The holder  10  may allow the use of a driver or handle  54  with multiple instruments, as discussed herein, with only one or a single registration or calibration. 
     The holder  10  may include a body or chassis portion  14 . The body  14  may include various features or sections. The sections may include a motor or handle assembly engaging region  16  that may be generally annular or selectively shaped to engage a driver or handle. An extension or open region or member  20  may extend from the handle assembly engaging region  16 . The extension region may be generally U-shaped. A guide or passage portion  24  may extend from the extension region  20 . The guide portion  24  may include a central bore of cannula  24 ′ that may allow passage of an instrument, as discussed herein. The guide portion  24  may have buttresses  25  on one or more sides extending from the extension region  20  to assist in supporting the guide  24 . 
     The holder  10  may be formed as one piece (i.e. a single and/or unitary piece) or plurality of pieces. As discussed herein, the holder  10  may be selected to be formed of a rigid material. The rigid material may have a selected rigidity such that the holder  10  does not vary in shape or dimension during use. For example, the holder  10  maintains an initial shape during use of the holder  10  to hold tracking members  30  during use of an instrument  52  ( FIG. 4 ). 
     In various embodiments, the holder  10  may be molded as a single piece of polyethylene, such as ultra-high molecular weight polyethylene, such as that used for bearing members. The material of the holder  10  may be a selected bearing material and/or a bearing material (e.g. a metal sleeve) may be provided in the bore  24 ′. The holder  10  may also be formed of more than one material and/or members that are fixed together. The holder  10  may be formed entirely or partially of metal, metal alloys, polymers, filled polymers (e.g. glass filled nylon), or other appropriate materials. 
     The material selected for the holder  10  may further include additional properties. For example, the holder  10  may have a selected anti-slip or gripping property. The holder  10  may also be selectively reusable and sterilizable (e.g. with gas sterilization, radiation sterilization, etc.). Also, or alternatively, the holder  10  may be disposable and only single use. 
     The holder  10  may further include one or more positions, such as posts or projections  28 , for holding the tracking devices or trackable members  30 . For example, the tracking member  30  may include a recess or depression that engages (e.g. frictionally engages) the projection or post  28  that extends from a wing or portion  29  of the holder  10 . The wing may extend from an arm or portion of the extension portion  24 . In various embodiments, the trackable members  30  may snap to the posts  28 . The tracking member  30 , therefore, may be removably fixed to the holder  10 . The tracking member  30  may include one or more tracking members, such as a first trackable member  30   a , a second track trackable member  30   b , a third trackable member  30   c , and a fourth trackable member  30   d  (referred to herein collectively of tracking or trackable members or devices  30 , unless specifically referred to individually). It is understood that more or less than four of the trackable members  30  may be provided with the holder  10 . Further, the trackable members  30  may be formed as one piece with the chassis  14 . 
     With additional reference to  FIG. 4 , the tracking members  30  may be any appropriate tracking members that may be tracked by a tracking system  34 . The tracking devices  30  may be tracked by the tracking system  34 , which may be incorporated or included with a navigation system  36 . In tracking the holder  10  with the tracking members  30 , a position (including a three dimension location and orientation (e.g. 1 or more degree of freedom, e.g. six degrees of freedom)) of the holder  10  an item to which it is attached may be determined. 
     In various embodiments, the tracking devices  30  may include members that are viewable by one or more cameras of the optical or camera localizer  38 . In various embodiments, therefore, the tracking system  32  may be an optical or light tracking system. In an optical tracking system the tracking members  30  may reflect (e.g. passive) or emit (e.g. active or LEDs) wavelengths of light that are visible or invisible (e.g. infrared wavelengths) that are detected by the cameras  38   a ,  38   b . The tracking devices  30  may also or alternatively include one or more coils that may be trackable with an electromagnetic (EM) tracking system localizer. The EM localizer may include one or more coils or antennas  42  of a tracking coil array  46  that may generate a field in a navigation volume  48 . 
     Regardless of the specific configuration or type, the tracking devices  30  may be positioned on the holder  10  to assist in tracking an instrument or tool  52 , as illustrated in  FIG. 3 . Generally, the instrument  52  is able to rotate. For example, the driver  54  may include a motor that rotates the instrument  52  or the handle  54  is able to be used by the user  56  to rotate the instrument  52 . The holder  10 , however, generally holds the trackable members  30  at a selected single position relative to the handle  54  during use and for tracking. 
     In various embodiments, the holder  10 , including the trackable members  30 , may be referred to as a tracking device. The instrument  52  may be assembled or connected to a handle or drive assembly  54 . The handle, as a drive assembly,  54  may include a motor for rotating the instrument  52 . The motor in the handle  54  may be any appropriate motor such as pneumatic motor, an electrical motor, or the like. Generally, a user  56  may hold a selected portion of the handle  54 , such as a grasping handle  58 . If the handle  54  is powered, the user  56  may depress or engage one or more control mechanisms, such as a button  60 , to cause the motor included within the driver  54  to move a chuck assembly  64 , such as rotating the chuck assembly  64  that is generally within the extension region  20 . Rotating the chuck assembly  64  may rotate the instrument  52 . 
     In various embodiments, the instrument  52  may include an elongated shaft  66  and a working end  68 . The working end  68  may be any appropriate working end such as a tap, a screw, an awl, or any appropriate working end. Further, the working end  68  may include a distal or terminal end or portion  68   a . Regardless, the user  56  may engage the driver  54  to cause the working end  68  to engage a selected portion, such as a portion of a patient  70 . 
     The instrument  52 , as discussed above, can be any appropriate instrument. In various embodiments, the instrument  52  may include the working end  68  to include a tap, such as a tap to form a thread in a bore in a bone. Further, the working end  68  may include a terminal or distal end  68   a . The position of the working end  68  may be selected to be precisely known and/or determined. Thus, the tap at the working end  68  may be selected to be precisely and/or knowingly positioned relative to the patient  70 . For example, for forming and tapping a bore at a precise and/or preselected position for a bone screw. Further, an instrument  52 ′ may include a screw at the working end  68 ′. It is understood, however, that any appropriate number of instruments may be provided with different or the same working end. 
     In various embodiments, the selected position of the instrument  52  may be selected to be substantially precise, such as for positioning a pedicle screw, implant, deep brain simulation probe, or the like. Accordingly, a determined position of the instrument  52  with the tracking system  32  may assist in navigation of the instrument  52  with the navigation system  34 . As discussed further herein, the position of the instrument  52  may be determined with the tracking system  32  and illustrated on a display device  72 , such as with an icon  52   i . The icon  52   i  may illustrate the position of the instrument  52  relative to the patient  70  represented by an image  74 . The image  74  may also be displayed on the display device  72  and the icon  52   i  may be superimposed thereon. The user  56  may, therefore, view the display device  72  to determine or view a representation of the instrument  52  relative to the patient  70  by viewing the icon  52   i  relative to the image  74 . 
     The instrument  52 , which may be a first instrument, may be substituted or changed to a different instrument, such as an instrument  52 ′, also referred to as a second instrument  52 ′. The instrument  52 ′ may include a working end  68 ′ that may be different than the working end  68 , and may include a screw which may be placed in the bore tapped with the tap  68 . In various embodiments, the working end  68  may include a tap which is formed and configured to tap a portion of the patient  70 , such as a vertebra, and the screw  68 ′ may be positioned in the tapped opening or bore. During a selected procedure, the instrument  52 , including the shaft  66 , may be removed from the handle  54  including the chuck  64 . A shaft  66 ′ of the instrument  52 ′ may then be positioned within the chuck  64  for driving the screw  68 ′ into the subject or patient  70 . 
     The holder  10  may remain fixed to the handle  54 , with the connections as discussed herein, while the instrument  52  and/or  52 ′ is positioned or repositioned (e.g. passed through the holder  10 ) to the handle  54 . For example, in various embodiments, the shaft  66  of the instrument  52  may be first connected to the handle  54 . At a selected time, such as after using the instrument  52  (e.g. to tap a bore), the shaft  66  may be withdrawn or removed through the extension or guide portion  24  of the holder  10  while the holder  10  remained attached to the handle  54 . Once the instrument  52  is removed, and the shaft  66 ′ of the instrument  52 ′ may be passed through the guide or shaft holder  24  into the chuck  64  in a reverse manner. While the instrument  52  is removed from the tool  54  and the instrument  52 ′ engaged therewith, the tracking device holder  10  may be maintained on the tool  54 . Accordingly, the instrument  52  need be the only portion or member removed from the tool  54  and the instrument  52 ′ positioned into the tool  54  without moving or changing the tracking device holder  10 . This can reduce the time of a procedure by, for example, eliminating calibration or recalibration of the holder  10  with the trackable members relative to the handle  54  after changing an instrument relative to the handle  54 . 
     To assist in holding or to maintain fixation of the holder  10  to the handle  54 , in various embodiments, the holder  10  may include a tool or handle engagement mechanism at the tool engagement portion  16 . For example, a friction engagement or holding member  80  is positioned within a receiving groove or portion  82  of the tracking device holder  10 . The friction member  80  may include an O-ring formed of a selected material, such as a butyl rubber or other synthetic or natural rubber material. The ring  80  may extend or project from the groove  82  and engage an external surface or a portion of the tool  54 . The engagement of the holding member  80  with the tool  54 , such as the friction engagement, may not be overcome by movement of the instrument  52 ,  52 ′ through the guide portion  24 . 
     The tracking device holder  10  may be positioned at selected and fixed positions relative to the tool  54  through engagement of one or more indents  90  formed as depressions or passages in an end wall  92  and having an internal wall  94 . The internal wall  94  of the indent or groove  90  may engage a holding pin  98  that extends from the tool  54 . The holder  10  may then be positioned at a selected rotational position around an axis  100  extending through the tool  54 . As illustrated in  FIG. 1 , the tracking device holder  10  may include six indents or positions  90  at the tool engaging portion  16 . It is understood that more or fewer indents or positional members may be provided with the tracking device holder  10 . Regardless, the holder  10  may be oriented such that when pressed on the handle  54  the pin  98  will be received within the indent  90  to rotational fix the holder  10  relative to the handle  54 . It is understood, however, that the handle  54  may include one or more depressions that receives a pin or projection of the holder  10 . 
     The tracking members  30  may be placed generally on a plane  102  or on a selected side of the plane  102 . The plane  102  may be defined by at least a portion of the holder  10 . Thus, the holder  10  may rotate to rotate the plane around the axis  100  and be held in the selected position relative to the handle  54 . The plane  102 , therefore, may be positioned in a selected, e.g. optimal view or line of sight of the localizer  38 . 
     The engagement feature or mechanism  80  may include alternative and/or additional engagement features. For example, the tool engagement portion  16  may include an internal thread that engages an external thread defined or formed by the tool  54 . The holder  10  may then be threaded onto the tool  54 . Further, or alternatively thereto, a quick connect mechanism may be provided to engage the tracking device holder  10  with the tool  54 . For example, a holding member or ball may be retracted into the tool  54  when engaged by the tracking device holder  10  and then rebound or be biased into the holding portion or groove  82  in the tracking device holder  10  when the tracking device holder  10  is positioned at a selected position relative to the tool  54 . Accordingly, it is understood, that the tracking device holder  10  may be held relative to the tool  54  in any appropriate manner. Further, the tracking device holder  10  may be positioned at a selected rotational position relative to the tool  54  and held at the selected position. 
     As discussed further herein tracking the tool  54  and/or the instrument  52 ,  52 ′ may require that the tracking devices  30  be positioned at a fixed and known position relative to the tool  54  and/or the instrument  52 ,  52 ′. Accordingly, the tracking device holder  10  may hold the tracking devices  30  at a fixed and selected position relative to the tool  54  during a procedure. Prior to tracking the instrument  52 ,  52 ′ (e.g. during a procedure), the tracking devices  30  may be calibrated or registered relative to a portion of the instrument  52  (e.g. the working end  68  and/or the terminal end  68   a ) and/or the tool  54 . In various embodiments, calibration may occur with a fiducial or fixed/known point registration procedure as is generally understood in the art. 
     For example, calibration may occur by tracking the holder  10 , including the tracking devices  30 , positioned on the tool  54 . With or without the instrument  52 ,  52 ′ positioned within the tool  54 , the positions of the tracking devices  30  relative to the tool  54  may be determined. For example, the holder  10  may engage a selected feature, such as a divot, at a known position relative to the localizer  38 . The navigation system  34  may then determine the position of the tracking devices  30  relative to the tool  54 . The instrument  52 ,  52 ′ may then be engaged with the tool  54  and the navigation system  34  may recall from a navigation memory  110  a geometry of the instrument  52 ,  52 ′. The navigation system  34  may then, knowing the geometry of the instrument  52 ,  52 ′ and the position of the tracking devices  30  relative to the tool  54 , determine the position of the working end  68 ,  68 ′ based upon the known geometry of the respective tools  52 ,  52 ′. It is further understood that the user  56  may enter a geometry of the instruments  52 ,  52 ′ rather than having them recalled from the navigation memory  110 . 
     Regardless, the tracking device holder  10  is used to fixedly hold the tracking devices  30  relative to the tool  54  and/or the instrument  52 ,  52 ′. Thus, the user  56  need not directly engage the holder  10 . Further, the geometry of the tracking device holder  10  allows for the instrument  52  to be engaged and disengaged from the tool  54  and the instrument  52 ′ to be engaged and disengaged from the tool  54  without removing the tracking device holder  10  or moving the tracking device holder  10  relative to the tool  54 . Therefore, once the tracking device holder  10  and the tracking devices  30  positioned therewith are registered or calibrated relative to the tool  54  the instrument may be changed relative to the tool  54  without requiring recalibration of the position of the tracking devices relative to the tool and/or with the respective instruments  52 ,  52 ′. 
     The selected instrument  52 ,  52 ′ (or other appropriate instrument), therefore, may be used to perform a procedure on the subject  70 . In various embodiments, with reference to  FIG. 4 , therefore, the tracking device holder  10  is used by the user  56  to position and/or navigate the instrument  52  relative to the subject  70 . For example, the instrument may include a tap at the working end  68  to tap (e.g. form threads in a bore) in a selected portion of the subject  70  including a vertebrae  120 . The image  74  may include an image of the vertebrae  120  as a vertebrae image  124 . The icon  52   i  may be illustrated on the display device  72  relative to the image  124 . 
     The navigation system  34  may be used for various purposes or procedures by one or more users, such as the user  56 . The navigation system  56  may be used to determine or track a position of the instrument  52  in a volume, such as the navigation or tracking volume  48 . Tracking the position of the instrument  52  may assist the user  56  in determining a position of the instrument  162  even if the instrument  52  is not directly viewable by the user  56 . Various procedures may block the view of the user  56 , such as performing a repair or assembling an inanimate system, such as a robotic system, assembling portions of an airframe or an automobile, or the like. Various other procedures may include a surgical procedure, such as performing a spinal procedure, neurological procedure, positioning a deep brain simulation probe, or other surgical procedures on a living subject. In various embodiments, for example, the living subject may be a human subject  70  and the procedure may be performed on the human subject  70 . It is understood, however, that the instrument  52  may be tracked and/or navigated relative to any subject for any appropriate procedure. 
     Nevertheless, in various embodiments, the surgical navigation system  34 , as discussed further herein, may incorporate various portions such as those disclosed in U.S. Pat. Nos. RE44,305; 7,697,972; 8,644,907; and 8,842,893; and U.S. Pat. App. Pub. Nos. 2004/0199072, all incorporated herein by reference. Various components that may be used with or as a component of the surgical navigation system  34  may include an imaging system  130  that is operable to image the subject  70 , such as an O-armø imaging system, magnetic resonance imaging (MRI) system, computed tomography system, etc. A subject support  132  may be used to support or hold the subject  70  during imaging and/or during a procedure. The same or different supports may be used for different portions of a procedure. 
     Image data may be acquired during a surgical procedure or acquired prior to a surgical procedure for displaying the image  74  on the display device  72 . The instrument  52  may be tracked in the trackable volume or the navigational volume  48  that is defined by the tracking system, including the localizer  38 ,  40 . The position of the instrument  52  may be tracked in the tracking volume relative to the subject  70  and then illustrated as the icon  52   i  with the display device  72 . In various embodiments, the icon  52   i  may be superimposed on the image  74  and/or adjacent to the image  74 . As discussed herein, the navigation system  34  may incorporate the display device  72  and operate to render the image  74  from selected image data, display the image  74 , determine the position of the instrument  52 , determine the location of the icon  52   i , etc. 
     In various embodiments, the localizer  46  may be an electro-magnetic (EM) localizer that is operable to generate electro-magnetic fields with a transmitting coil array (TCA)  42  which is incorporated into the localizer  46 . The TCA  42  may include one or more coil groupings or arrays. In various embodiments, more than one group is included and each of the groupings may include three coils, also referred to as trios or triplets. The coils may be powered to generate or form an electro-magnetic field by driving current through the coils of the coil groupings. As the current is driven through the coils, the electro-magnetic fields generated will extend away from the coils  42  and form the navigation domain or volume  48 , such as encompassing all or a portion of the subject  70 , including spinal vertebrae  120 , or other appropriate portion. The coils may be powered through a TCA controller and/or power supply  136 . 
     The navigation domain or volume  48  may also be defined by a volume or area that is viewable by cameras of the localizer  38 . In various embodiments a selected number of cameras (e.g. two cameras  38   a ,  38   b ) may view the volume  48 . The volume viewable by the localizer  38  may include the navigation volume  48 . The position of the tracking device or trackable members  30  may be determined relative to a patient tracker  140 , that is also viewable, or relative to the localizer  38  (e.g. if the localizer  38  is fixed relative to the subject  70 ). 
     The navigation domain or volume  48  generally defines a navigation space or patient space. As is generally understood in the art, the instrument  52 , such as discussed above, may include a drill, lead, etc., may be tracked in the navigation domain relative to a patient or subject  70  with the tracking assembly  10  including the trackable members  30 . For example, the instrument  52  may be freely moveable, such as by the user  56 , relative to the dynamic preference frame (DRF) or reference frame tracker  140  that is fixed relative to the subject  70 . Both the tracking devices  10 ,  140  may include trackable members  30  and/or tracking or sensing coils (e.g. conductive material formed as a coil) that sense and are used to measure a magnetic field strength, etc. Due to the tracking device  10  connected or associated with the instrument  52 , relative to the DRF  140 , the navigation system  30  may be used to determine the position of the instrument  52  relative to the DRF  140 . 
     The navigation volume or patient space may be registered to an image space of the patient and the icon  52   i  representing the instrument  52  may be illustrated at a known and tracked location with the display device, such as superimposed on the image  74 . Registration of the patient space to the image space and determining a location of a tracking device, such as with the tracking device  10  relative to the DRF  140 , may be performed as generally known in the art, including as disclosed in U.S. Pat. Nos. RE44,305; 7,697,972; 8,644,907; and 8,842,893; and U.S. Pat. App. Pub. Nos. 2004/0199072, all incorporated herein by reference. 
     The navigation system  34  may further include a navigation processor system  146 . The navigation processor system  146  may include the display device  72 , one or more of the localizers  38 ,  40 , the TCA controller  136 , and other portions and/or connections thereto. For example, a wire connection may be provided between the TCA controller  136  and a navigation processing unit  148 . Further, the navigation processor system  146  may have one or more inputs, such as a keyboard  150 , and have and/or be in communication with one or more memory systems  110 , either integrated or via a communication system. The navigation processor system  146  may, according to various embodiments, include those disclosed in U.S. Pat. Nos. RE44,305; 7,697,972; 8,644,907; and 8,842,893; and U.S. Pat. App. Pub. Nos. 2004/0199072, all incorporated herein by reference, or may also include the commercially available StealthStation or Fusionú surgical navigation systems sold by Medtronic Navigation, Inc. having a place of business in Louisville, Colo. 
     Tracking information, including regarding the viewed and/or triangulated position of the tracking devices  10 ,  140  may be delivered via a communication system, such as the TCA controller, which also may be a tracking device controller  136 , to the navigation processor system  146  including the navigation processor  148 . Navigation processor  148  may be a part of the work station or computer system  146  that includes the display device  72  to display the image  74 . Various other memory and processing systems may also be provided with and/or in communication with the processor system  148  such as an imaging processing unit  154 . The image processing unit  154  may be incorporated into the imaging system  130 , such as the O-armø imaging system, as discussed above. The imaging system  130  may, therefore, include various portions such as a source and a x-ray detector that are moveable within a gantry  160 . The imaging system  130  may also be tracked with a tracking device  166 . It is understood, however, that the imaging system  130  need not be present while tracking the tracking devices, including the instrument tracking device  10 . Also, the imaging system  130  may be any appropriate imaging system including a MRI, CT, etc. 
     Information regarding all of the tracking devices may be communicated to the navigation processor  148  for determining a position of the tracked portions relative to each other and/or for localizing the instrument  52  relative to the image  74 . The imaging system  130  may be used to acquire image data to generate or produce the image  74  of the subject  70 . It is understood, however, that other appropriate imaging systems may also be used. The TCA controller  136  may be used to operate and power the TCA  46  and or the localizer  38 , as discussed above. 
     In various embodiments, therefore, and with continuing reference to  FIGS. 1-4 , the holder  10 , also referred to as the tracking device or assembly, may be tracked with the tracking system  32 , such as with the localizer  38 , to determine a position of the instrument  52  with the navigation system  34 . As discussed above, tracking may occur due to the tracking members  30  that are held by the holder  10  relative to the handle  54 . During a procedure, however, the instrument  52  and/or  52 ′ may be removed and replaced with the other of the instrument  52 ,  52 ′ without removing the holder  10 . Thus, only the instrument  52 ,  52 ′; may be removed from the handle  54 . It is understood, however, that other additional instruments may also be positioned relative to the handle  54  after removing the exemplary disclosed instruments. 
     As discussed above, the holder  10  including the trackable members  30  may be a registered and/or calibrated relative to the handle  54  prior to tracking any instruments and/or performing a procedure on the subject  70 . In various embodiments, therefore, the holder  10  may be fitted to the handle  54 , as discussed above, and then calibrated or registered. The calibration may include predetermining (e.g. during a manufacture) a geometry of the holder  10  and/or the members  30  relative to the handle  54  and saving the predetermined geometry. The predetermined geometry may then be recalled, such as by the user  56 , once assembling the holder  10  to the handle  54 . The navigation processing unit  148  may recall from the navigation memory  110  the predetermined geometry and use the recalled predetermined geometry for calibration of the holder  10  relative to the handle  54 . The geometry of the instrument, such as the instrument  52 , can also then be calibrated and/or recalled from the navigation memory  110  to be able to track the position of the instrument  52 , including the working end  68 . 
     Alternatively, or in addition to a lookup table or recalling from memory, the tracking system  32  may be calibrated during use. For example, the holder  10  may be positioned or fit to the handle  54  in a selected manner, as discussed above. A portion of the holder  10 , once fitted to the handle  54 , may then be touched to a known or registerable portion, such as a divot formed by the DRF  140 . For example, a distal end of the holder or selected portion thereof, such as a projection  10   c  may engage a divot (e.g. shaped indent in the DRF  140 ). Once the distal end, for example the projection  10   c , engages the divot of the DRF  140  the tracking system  32  may be operated to calibrate or determine a position of the projection  10   c  in the navigation volume  70 . Therefore during a procedure the geometry or position of at least a portion of the holder  10  may be determined during a procedure. Then the instrument  52  fixed to the handle  54  may also be touched to the divot of the DRF  140  to know the distal end of the working end  68  relative to the end or projection  10   c  of the holder  10 . 
     Upon removal of the instrument  52  and insertion of the instrument  52 ′, the calibration of the holder  10  relative to the handle  54  need not be repeated, especially if and/or only if the holder  10  is not removed from the handle  54  during removal of the instrument  52  and/or insertion of the instrument  52 ′. The instrument  52  may be removed through the holder  10  and the instrument  52 ′ may be inserted into the handle  54  through the holder  10 . 
     Accordingly, the holder  10 , including the trackable members  30 , may be calibrated relative to the handle  54  at a single time and only one time, such as prior to a procedure or during a procedure. After the calibration, instruments may be removed and inserted, such as serially or sequentially, with the handle  54  without requiring recalibration of the holder  10  including the trackable members  30 . Thus, the user  56  may select different instruments and attach the different instruments at selected different times to the handle  54  without requiring recalibration of the holder and the trackable members  30  to continue tracking and navigation of the selected instrument  52 . Therefore the position (i.e. including a three dimensional location and selected degrees of freedom of orientation (three degrees of freedom)) may be made with the tracking system  32  to allow for navigation of the instrument  52  with the navigation system  34 . 
     Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.