Patent Publication Number: US-2021178125-A1

Title: Systems and methods for anchoring medical devices

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 16/240,036, filed on Jan. 4, 2019, which is a continuation of U.S. patent application Ser. No. 15/587,821 filed May 5, 2017, which is a continuation of U.S. patent application Ser. No. 15/175,735 filed Jun. 7, 2016, which is a continuation of U.S. patent application Ser. No. 14/594,516 filed Jan. 12, 2015, which is a continuation of U.S. patent application Ser. No. 13/705,651 filed on Dec. 5, 2012 by Rosenberg et al., which is a continuation of U.S. patent application Ser. No. 12/893,783 filed on Sep. 29, 2010 by Rosenberg et al., the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This document relates to a system and method for securing the position of a catheter or another medical instrument, for example, at a skin opening. 
     BACKGROUND 
     Venous, arterial, and body fluid catheters are commonly used by physicians. For example, such catheters may be used to gain access to the vascular system for dialysis, for introducing pharmaceutical agents, for nutrition or fluids, for hemodynamic monitoring, and for blood draws. Alternatively, catheters can be used for drainage of fluid collections and to treat infection. Following introduction into the patient, the catheter is secured to the patient. In some instances, the catheter is commonly secured to the patient using an adhesive tape on the skin or by suturing a catheter hub to the patient&#39;s skin. In other circumstances, the catheter may be secured to the patient using a subcutaneous anchor mechanism (such as an anchor sleeve equipped with anchors that are deployed using an external actuator handle or a separate delivery device). 
     SUMMARY 
     Some embodiments of a medical device anchor system include an anchor device that secures a medical instrument (such as a catheter or the like) in place relative to a skin penetration point using subcutaneous anchors that are readily inserted without the use of a deployment actuator. In some implementations, the anchor device can be installed using a technique in which the subcutaneous anchors undergo relatively little or no flexing when being inserted through the skin into the subcutaneous region (e.g., the region immediately under the skin and between the skin and underlying muscle tissue which may be occupied by fatty tissue). As such, the subcutaneous anchors of the anchor device may be inserted through the skin penetration point that is already occupied by the medical instrument while in a generally non-stressed or non-flexed shape. According to certain implementations of the installation technique, the subcutaneous anchors can also be shifted to a different orientation after installation into the subcutaneous region, yet the subcutaneous anchors may continue to be maintained in generally the same shape as during insertion through the skin penetration point. Accordingly, the subcutaneous anchors of the anchor device can be installed through the skin and into the subcutaneous region using a technique that reduces or eliminates flexing of the subcutaneous anchors, thereby permitting the use of more rigid materials for subcutaneous anchors (e.g., comprising materials without superelastic characteristics). 
     In particular embodiments, the anchor device may have a foldable configuration that facilitates both installation and removal of the subcutaneous anchors in a manner that reduces trauma to surrounding tissue near the skin penetration point. For example, the anchor device can be retained in a folded condition during installation of the subcutaneous anchors through the skin penetration point while each of the subcutaneous anchor tines has a first curved shape (e.g., a generally non-stressed or non-flexed shape). Also, the anchor device can be adjusted to a non-folded condition after installation of the subcutaneous anchors into the subcutaneous region, and each of the anchors tines can have generally the same first shape after the device is adjusted to the non-folded condition. The action of adjusting the anchor device to the non-folded condition can cause the subcutaneous anchors to shift relative to one another so that the subcutaneous anchors extend outwardly away from one another, yet may each maintain the first curved shape (e.g., generally non-stressed or non-flexed shape). During removal, the anchor device can be adjusted again to the folded condition so that the subcutaneous anchors are positioned side-by-side and extend generally in the same direction while also each maintaining generally the same first curved shape. In these circumstances, the subcutaneous anchors can be contemporaneously installed and removed from the skin penetration point in a manner that reduces the likelihood of damage to the tissue surrounding the skin penetration point while also reducing or eliminating flexing of the subcutaneous anchors. 
     Some embodiments of a method of using a medical anchor system may include the step of advancing an anchor device toward a skin penetration point while the anchor device is in a folded condition so that a plurality of subcutaneous tines of the anchor device are generally adjacent to each other and oriented to extend in substantially the same direction. The method may also include inserting the subcutaneous tines through the skin penetration point and into a subcutaneous region adjacent to an underside of a skin layer while the anchor device is in the folded condition. Each of the subcutaneous tines may have a curved shape which terminates at a tip of a free end during insertion through the skin penetration point. The method may further include adjusting the anchor device to a non-folded condition after the subcutaneous tines are inserted into the subcutaneous layer so that subcutaneous tines are in an anchored position in which the free ends of the subcutaneous tines extend generally away from one another. Also, the method may include securing a medical instrument to the anchor device after the subcutaneous tines are adjusted to the anchored position in the subcutaneous region. 
     These and other embodiments may provide one or more of the following advantages. First, some embodiments of an anchor system can retain a medical instrument in a desired position relative to a skin penetration point without necessarily requiring sutures or skin adhesives. Second, in some embodiments, the anchor device can be installed in accordance with a technique that reduces or eliminates the need to shift the subcutaneous anchors tines to or from a flexed or stressed configuration. As such, the anchor tines need not undergo substantial flexing during installation or removal. Third, in some embodiments the subcutaneous anchor tines need not have superelastic characteristics due to the installation and removal technique, so the subcutaneous anchor tines can comprise a generally less costly material (such as stainless steel or biocompatible polymers) rather than more costly materials required for superelastic flexing. Fourth, the subcutaneous anchors can be positioned distally of the retention portion that that readily mates with a medical instrument (such as a catheter), thereby enabling the subcutaneous anchors tines to be secured in the subcutaneous region under the skin while the catheter or other medical device is retained externally from the skin. Fifth, in some embodiments, the anchor device may be adjusted between a folded configuration and a non-folded configuration so that the subcutaneous anchors are arranged side-by-side and extend in generally the same direction during both installation through and removal from the skin penetration point. In these circumstances, the subcutaneous anchors may be readily installed and removed from the skin penetration without the need for a separate external actuator or delivery device. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of an anchor device with a portion of the device located in a subcutaneous region, in accordance with some embodiments. 
         FIGS. 2-3  are top and front views, respectively, of the anchor device of  FIG. 1  with the medical device retention portion in an open and deployed configuration. 
         FIGS. 4-7  are perspective views of a method of using an anchor system, including the anchor device of  FIG. 1 , for use in securing the position of a medical instrument. 
         FIG. 8  is a perspective view of an anchor device for use in the method of  FIGS. 4-7 , including a mechanism for retaining the anchor device in a folded condition in accordance with some embodiments. 
         FIG. 9  is a perspective view of an anchor device for use in the method of  FIGS. 4-7 , including another mechanism for retaining the anchor device in a folded condition in accordance with other embodiments. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     Referring to  FIG. 1 , some embodiments of a medical device anchor system  10  include an anchor device  100  that releasably retains a medical instrument  20  (e.g., depicted as a catheter in this embodiment) in an operative position relative to a portion of skin  30  (e.g., relative to a skin penetration point  32 ). The anchor device  100  may include a base  110  and a cap assembly  130 . The base  110  may include a retainer body  111  and one or more anchors  140   a - b  that extend distally from the retainer body  111  for deployment in a subcutaneous layer  34 . As described in more detail below in connection with  FIGS. 4-7 , the anchor device can be installed into a skin penetration point  32  in accordance with a technique that reduces or eliminates the need to shift subcutaneous anchors tines  145   a - b  of the anchors  140   a - b  to or from a flexed or stressed configuration. As such, the anchor tines need not undergo substantial flexing during installation or removal. In these circumstances, the subcutaneous anchors may be both installed and removed from the skin penetration advantageously without the need for an external actuator handle or delivery device to deploy the subcutaneous tines. 
     As shown in  FIG. 1 , after installation of the subcutaneous anchor tines  145   a - b  into the subcutaneous layer  34 , the base  110  can receive the medical instrument  20 , and the cap assembly  130  can be removably coupled to the base  110  to secure the medical instrument  20  in a generally fixed position relative to the base  110 . The base  110  and the cap assembly  130  can include gripping members  120  and  135 , respectively (refer also to  FIGS. 2-3 ). When the cap assembly  130  is coupled to the base  110 , the gripping members  120  and  135  can releasably engage with an outer surface of the medical instrument  20 . The medical instrument  20  can extend from the gripping members  120  and  135  and through a skin penetration point  32  in a patient&#39;s skin  30 , while the retainer body  111  and the gripping members  120  and  135  remain outside of the skin  30 . IN some embodiments, the skin penetration point  32  may be defined by a small incision, a puncture, or the like. 
     As described in more detail below, the anchor device  100  can secure the catheter  20  in the operative position relative to the penetration point  32  without necessarily requiring sutures or adhesive tapes bonded to the skin. For example, the base  110  can include the one or more anchors  140   a  and  140   b  that extend distally from the retainer body  111  so as to penetrate through the same skin opening as the medical instrument  20 . The anchors  140   a  and  140   b  can include the tines  145   a  and  145   b  that, after insertion, reside in the subcutaneous region  34  so as to secure the position of the anchor device  100 —and the medical instrument  20  retained therein—relative to the penetration point  32 . 
     Referring now to  FIGS. 1-3 , in some embodiments, the medical instrument  20  can include a catheter to be inserted through the penetration point  32  of the skin  30  as part of a medical procedure. For example, in the embodiment depicted in  FIG. 1 , a central venous catheter  20  can be inserted into a percutaneous opening surgically formed in the skin (e.g., penetration point  32 ), to the underside of the skin  30 , and into a vein  40  to provide vascular access for delivering medications or minimally invasive devices into a patient. After placement of the catheter  20 , the base  110  of the anchor device  100  can approach the penetration point  32  such that the free ends of the tines  145   a - b  are contemporaneously inserted through the penetration point  32  while the tines  145   a - b  are in a generally side-by-side condition (refer, for example, to  FIGS. 4-5 ). As the anchor device  100  is inserted through the penetration point  32 , the tines  145   a - b  are maintained in a generally non-stressed configuration (e.g., a first shape or a steady-state shape) while passing through the penetration point  32  in a manner that reduces the likelihood of trauma to the surrounding skin tissue. As the tines  145   a - b  are collectively advanced through the penetration point  32 , the free ends of the tines  145   a - b  are moved beneath the dermal skin layers  36  of the skin  30 . When the tines  145   a - b  reach the subcutaneous region  34 , the tines  145   a - b  can be shifted relative to one another so that the tines  145   a - b  extend outwardly away from one another while each tine  145   a - b  retains the generally non-stressed configuration (e.g., the first shape or the steady-state shape). Thus, as described in more detail below in connection with  FIGS. 4-7 , the anchor device  100  can be installed in accordance with a technique that reduces or eliminates the need to shift the subcutaneous anchors tines  145   a - b  to or from a flexed or stressed configuration during the passage through the skin penetration point. As such, the subcutaneous anchors tines  145   a - b  need not undergo substantial flexing during installation or removal, and in some embodiments, the subcutaneous anchors tines  145   a - b  can comprise a generally less costly material (such as stainless steel or biocompatible polymers) rather than more costly materials required for superelastic flexing. 
     Referring now to  FIG. 2 , each of the anchors  140   a - b  may be designed such that the tines  145   a - b  has a first shape with a convex curvature that abuts against the underside of the dermal layers  36  in a manner that reduces the likelihood of the tine tips  146  puncturing the underside of the dermal layers  36 . Preferably, the tine tips  146  are rounded or otherwise non-sharp so as to further protect the underside of the dermal layers. When the tines  145   a - b  of the anchors  140   a - b  are deployed in the subcutaneous region  34 , the cap assembly  130  can be removably coupled to the base  110  (refer, for example to  FIG. 7 ), compressing the gripping portions  120  and  135  onto the medical instrument  20  and causing the gripping portions  120  and  135  to releasably engage with an outer surface of the medical instrument  20 . In this way, the anchor device  100  can be secured to the patient without the retainer body  111  penetrating though the skin  30  of the patient and without necessarily requiring sutures or adhesive tapes bonded to the skin  30 . 
     Referring now to  FIGS. 2-3 , some embodiments of the anchor device  100  can include structures designed to mate with portions of the medical instrument  20  to be retained by the anchor device  100 . The anchor device  100  can include the gripping members  120  and  135  used to secure the catheter  20  (or other medical instrument) relative to the skin penetration point  32 . For example, after the catheter  20  is delivered into the targeted vein  40  (or other bodily lumen) and after the tines  145   a - b  are anchored in the subcutaneous region  34 , the cap assembly  130  can be removably coupled to the base  110 , compressing the gripping members  120  and  135  to temporarily engage with the outer surface of the catheter  20 . In this way, the anchor device  100  can be transitioned from the open configuration (shown in  FIG. 2-3 ) to the closed configuration (shown in  FIG. 1 ) to thereby secure the catheter  20  with the gripping members  120  and  135 . As described in more detail below, the retainer body  111  can include locking tabs  112  that can pass through openings  132  in the cap  131  and positively engage at least a portion of perimeters  134  of the openings  132 , thereby removably coupling the cap assembly  130  to the base  110 . 
     Still referring to  FIGS. 2-3 , the anchor device  100  can include features that facilitate separation from the catheter  20 , which can permit the catheter  20  and anchor device  100  to be removed from the skin  30  independently of each other. For example, the tabs  112  may be disengaged from the cap assembly  130  to decouple the cap assembly  130  from the base  110 . Once the cap assembly  130  is removed, the gripping members  120  and  135  can release from the catheter  20 , thereby allowing the catheter  20  to be moved relative to the anchor device  100 . As such, the catheter  20  can be moved independently from the anchor device  100 , for example, to withdraw the catheter  20  from the patient while at least a portion of the anchor device  100  remains secured to the skin  30 . 
     Some embodiments of the anchor device  100  can include structures configured to mate with portions of the medical instrument  20  to be retained by the anchor device  100 . For example, when the anchor device is in the closed configuration (as depicted in  FIG. 1 ), the gripping members  120  and  135  can define a channel  122  (illustrated in  FIG. 2 ) that extends longitudinally from the proximal portion  103  of the anchor device  100  toward the anchors  140   a - b . The channel  122  can be configured to complement an outer surface of the catheter  20  or other medical instrument to be anchored by the device  100 . For example, during installation of the anchor device  100 , the anchors  140   a - b  are directed toward the penetration point  32  through which the catheter  20  passes. When the tines  145   a - b  are anchored in the subcutaneous region  34 , the cap assembly  130  can be removably coupled to the base  110 , which transitions the anchor device  100  to the closed configuration. As such, the catheter  20  can extend though the channel  122  when the subcutaneous tines  145   a - b  are arranged in the region immediately under the skin  30 . 
     In some embodiments, particular features of the anchor device  100  can removably couple the base  110  to the cap assembly  130 . In the example depicted in  FIG. 3 , the cap assembly  130  can be moved toward the base  110  (e.g., in the direction depicted by arrow  106 ) to direct the tabs  112  toward to the openings  132 . When the diagonal faces of the tabs  112  contact the perimeters  134 , the tabs  112  are stressed such that the tips  115  of the tabs  112  move closer to each other. When the face  135  moves beyond the engagement fingers  116 , the tabs  112  can outwardly toward their unstressed positions to releasably engage the perimeters  134 . When in this closed configuration, the cap assembly  130  and base  110  can apply a compressive force from the gripping members  120  and  135  to the catheter  20  in the channel  122 , thereby applying a frictional holding force to the catheter  20  or medical instrument therein. 
     In some embodiments, the holding force that secures the catheter  20  to the anchor device  100  can be released by separating the cap assembly  130  from the base  110 . The cap assembly  130  can be separated from the base  110  by disengaging the locking tabs  112  from the cap assembly  130 . For example, the base  110  can be separated from the cap assembly  130  by applying pressure to the locking tabs  112  to move the tips  115  closer to each other. When the engagement portions  116  of the tabs  112  move inside the openings  132  in the cap  131 , the retainer portions  120  and  135  force the cap assembly  130  away from the base  110  and the cap assembly  130  becomes decoupled from the base  110 , thus transitioning the anchor device  100  to the open configuration ( FIGS. 2-3 ). When the anchor device  100  is in the open configuration (e.g., with the cap  130  removed), the catheter  20  can be moved relative to the anchor device  100 . 
     Referring now to  FIGS. 4-7 , the anchor device  100  can be installed using a technique in which the subcutaneous anchor tines  145   a - b  undergo relatively little or no flexing when being inserted through the skin penetration point  32  into the subcutaneous layer  32  between the skin  30  and the underlying muscle tissue. As such, the subcutaneous anchors tines  145   a - b  can be inserted through the skin penetration point  32  that is already occupied by the catheter  20  while each tine  145   a - b  is maintained in a generally non-stressed or non-flexed shape. Also, as described in  FIGS. 6-7 , the subcutaneous anchors tines  145   a - b  can also be shifted to a different orientation after installation into the subcutaneous region  34 , yet the tines  145   a - b  may continue to be maintained in the generally non-stressed or non-flexed shape. Accordingly, the subcutaneous anchors of the anchor device can be installed through the skin and into the subcutaneous region using a technique that reduces or eliminates flexing of the subcutaneous anchors, thereby permitting the use of more rigid materials for subcutaneous anchors (e.g., comprising materials without superelastic characteristics). 
     In this embodiment, the anchor device  100  may include features that allow the individual anchors  140   a - b  to be moved relative to each other so as to facilitate both insertion and removal of the anchor device  100  through the skin penetration point. For example, the anchor device  100  may have a foldable configuration in which a first portion of the base  110  is pivotably coupled to a second portion of the base  110 . The anchor device  100  can include a left portion  101   a  and a right portion  101   b  (refer to  FIG. 2 ), which can be flexibly pivoted with respect to each other along a fold line  113  (refer to  FIG. 2 ) extending longitudinally through the retainer body  111 . The left portion  101   a  can include a left retainer body portion  114   a  (refer to  FIG. 2 ) fixedly coupled to the anchor  140   a,  and the right portion  101   b  can include a right retainer body portion  114   b  (refer to  FIG. 2 ) fixedly coupled to the anchor  140   b.  Thus, as shown in  FIG. 4 , when the left and right retainer body portions  114   a  and  114   b  are pivoted about the fold line  113 , the two anchors  140   a - b  likewise pivot relative to one another. This process can cause the anchor device to transition from a folded condition (shown in  FIGS. 4-5 ), in which the tines  145   a - b  are generally adjacent to each other and oriented to extend in substantially the same direction, to a non-folded condition (shown in  FIGS. 6-7  and in  FIG. 1 ), in which the tines  145   a - b  extend generally away from one another. In the depicted embodiment, the tines  145   a - b  can be rotated about 75-degrees to about 105-degrees, and preferably about 90-degrees, during the transition between the folded condition and the non-folded condition. As described in more detail below, the anchor device  100  can be arranged in the folded condition during both insertion and removal of the subcutaneous tines  145   a - b  so as to reduce the likelihood of the tines  145   a - b  causing damage to the skin  30 . 
     In particular embodiments, a method of using the medical anchor system (including the anchor device  100 ) may include an advantageous insertion technique. As shown in  FIG. 4 , the method may include a step of inserting a medical instrument (such as catheter  20 ) through the skin penetration point  32  (e.g., a puncture opening or incision) of the patient&#39;s skin  30 . One example of the catheter  20  being inserted through the penetration point  32  is depicted in  FIG. 4 . In this embodiment, the catheter  20  may include a central venous catheter that extends from a location external to the skin  30 , through the skin penetration point  32 , and into a blood vessel  40  ( FIG. 1 ) underlying the skin  30  and subcutaneous layer  34 . 
     As shown in  FIG. 4 , after the catheter  20  or other medical instrument is inserted so that it occupies the skin penetration point  32 , the method may include the step of advancing the anchor device  100  toward the skin penetration point  32  while in the folded condition. As previously described, when the base  110  of the anchor device  100  is in the folded condition, the subcutaneous tines  145   a - b  are generally adjacent to each other and oriented to extend in substantially the same direction. As such, the tips  146  of the subcutaneous tines  145   a - b  can located in a side-by-side position so that the tips  146  can be contemporaneously advanced to the skin penetration point  32  that is already occupied by the catheter  20  to be anchored. As described in more detail below, the anchor device  100  may be equipped with a clip device  160  or  170  ( FIG. 8 ) or a snap connector  180   a - b  ( FIG. 9 ) that retains the base  110  in the folded condition prior to insertion of the subcutaneous tines  145   a - b.    
     As shown in  FIG. 5 , the method may also include the step of inserting the subcutaneous tines  145   a - b  through the skin penetration point  32  while the base  110  of the anchor device  100  is in the folded condition. In such circumstances, the tips  146  of the subcutaneous tines  145   a - b  are generally adjacent to each other so that they can be the first portion of the subcutaneous tines  145   a - b  to initially advance through the skin penetration point  32  and into the subcutaneous layer  34 . Because the subcutaneous tines  145   a - b  are generally adjacent to each other and oriented to extend in substantially the same direction, the subcutaneous tines  145   a - b  can be simultaneously inserted while being maintained in a non-stressed configuration. For example, the subcutaneous tines  145   a - b  are not necessarily forced into a flexed or stressed configuration by another component of the anchor system  10  during insertion of the subcutaneous tines  145   a - b . In particular embodiments, the subcutaneous tines  145   a - b  are inserted through the skin penetration point  32  while the user grasps the base  110  of the anchor device  100  and applies a downward force until the convexly curved body portions of the subcutaneous tines  145   a - b  are positioned below the surface of the skin  30  (while the remainder of the anchor device  100  resides external to the skin  30 ). 
     As shown in  FIG. 6 , the method may also include adjusting the anchor device  100  to the non-folded condition after the subcutaneous tines  145   a - b  are inserted into the subcutaneous layer  34 . As previously described, the free ends of the subcutaneous tines  145   a - b  extend generally away from one another when the anchor device  100  is shifted to the non-folded condition. In such circumstances, the subcutaneous tines  145   a - b  are oriented in an anchored position in the subcutaneous layer  34  so as to anchor the retention portion  111  relative to the skin penetration point  32  that is occupied by the catheter  20 . When in the anchored position, each of the tines  145   a - b  can be maintained at generally the same shape as when they were inserted through the skin penetration point (e.g., the generally non-stressed shape in which in which no other components of the anchor system  10  are forcing the tines  145   a - b  to flex). Accordingly, the convex curvature of the tines  145   a - b  abuts against the underside of the skin  30  in a manner that reduces the likelihood of the tine tips  146  puncturing the underside of the dermal layers  36 . As previously described, the tine tips  146  are rounded or otherwise non-sharp so as to further protect the underside of the dermal layers. 
     As shown in  FIG. 7 , the method may also include securing the catheter  20  to the anchor device  100  after the subcutaneous tines  145   a - b  are anchored in the subcutaneous layer  34 . In this embodiment, the portion of the catheter  20  that is external to the skin  30  can be positioned in the channel  122  ( FIG. 2 ) of the base  110 . The cap assembly  130  can be removably coupled to the base  110  (refer, for example to  FIG. 1 ) so that the gripping portions  120  and  135  of the anchor device  100  releasably engage with the outer surface of the catheter  20 . In such embodiments, the anchor device  100  can be secured to the patient without the retainer body  111  penetrating though the skin  30  of the patient and without necessarily requiring sutures or adhesive tapes bonded to the skin  30 . As previously described in connection with  FIGS. 2-3 , the cap assembly  130  can be moved toward the base  110  (e.g., in the direction depicted by arrow  106 ) to close the anchor device  100  around the portion of the catheter that is external to the skin  30 . When in this closed configuration, the cap assembly  130  and base  110  can apply a compressive force from the gripping members  120  and  135  to the catheter  20 , thereby applying a frictional holding force to the catheter  20  or medical instrument therein. 
     The method may further include the step of anchoring the catheter  20  to the skin penetration point  32  using the anchor device  100  during delivery of treatment through the catheter  20 . For example, as shown in  FIG. 1 , the anchor device  100  can releasably anchor the catheter  20  to the skin penetration point  32  while the catheter  20  resides in a selected blood vessel  40  to deliver a particular treatment (e.g., to deliver a fluid, to extract a fluid, to deliver an instrument or implant, or the like). As shown in  FIG. 1 , the subcutaneous tines  145   a - b  serve to secure the anchor device  100  (and the catheter  20  secured thereto) to the skin penetration point  32  by abutting against an underside of the skin  30 . 
     The method may also include steps for removing the anchor device  100 . During removal, the anchor device  100  can be adjusted to the folded condition once again so as to facilitate a prompt removal of the subcutaneous tines  145   a - b  from the skin penetration point. Accordingly, the removal process will be substantially the opposite order of steps as shown in  FIGS. 4-7 . For example, during removal, the cap assembly  130  can be detached from the base  110  so that the catheter  20  can be freed from the base. The catheter  20  may be withdrawn from the skin penetration point before the subcutaneous tines  145   a - b  are removed, or alternatively, the catheter  20  may remain in place while the subcutaneous tines  145   a - b  are removed first. After the base  100  is free from the cap assembly  130  (in a condition similar to that of  FIG. 6 ), the base can be adjusted to the same folded condition employed during the insertion technique (refer to  FIG. 5 ). In such circumstances, the subcutaneous tines  145   a - b  are generally adjacent to each other and oriented to extend in substantially the same direction. As such, the subcutaneous tines  145   a - b  can be simultaneously removed while being maintained in a non-stressed configuration (refer to  FIG. 4 ). Such a removal process can be used to reduce the cross sectional area of the portion of the anchors  140   a - b  being withdrawn through the skin penetration point  32 , thereby reducing the likelihood of damaging the surrounding skin tissue  30  during removal of the anchors  140 - b.    
     Accordingly, the anchor device  100  may have a foldable configuration that facilitates both installation and removal of the subcutaneous anchors  140   a - b  in a manner that reduces trauma to surrounding tissue near the skin penetration point  32 . 
     Referring now to  FIGS. 8-9 , some embodiments of the anchor device  100  may include one or more structures that releasably retain the base  110  of the anchor device  100  in the folded condition. For example, the anchor device  100  may be provided in a sterile package while being retained in the folded condition. In such circumstances, a user can readily remove the device  100  and begin to insert the subcutaneous tines  145   a - b  through the skin penetration point  132  (as shown in  FIGS. 4-5 ) without having to manually adjust the base  110  to the folded condition. After insertion the subcutaneous tines  145   a - b  into the subcutaneous layer  32 , the user can then remove or separate the one or more structures that releasably retain the base  110  of the anchor device  100  in the folded condition. The anchor device  100  can be biased toward the non-folded condition (as shown in  FIG. 6 ) upon removal of the one or more structures. 
     As shown in  FIG. 8 , the some embodiments of the anchor device  100  may include one or more removable structures that releasably retain the base  110  of the anchor device  100  in the folded condition. For example, the removable structure may include a U-shaped clip device  160  that slidably engages the base  100 . The U-shaped clip device  160  can be readily removed from the base  110  by sliding the clip device  160  in a lateral direction generally perpendicular to the fold line  113  of the anchor device  100 . In a second example, the removable structure may include a different U-shaped clip device  170  that slidably engages the base  100  from a longitudinal direction. The U-shaped clip device  170  can be readily removed from the base  110  by sliding the clip device  160  in a longitudinal direction that is generally parallel to the fold line  113  of the anchor device  100 . 
     As shown in  FIG. 9 , the some embodiments of the anchor device  100  may include one or more structures that are integrally formed with another component of the anchor device  100  so as to releasably retain the base  110  of the anchor device  100  in the folded condition. For example, the structure may include a snap-fit connector having mating components  180   a - b  that secure together when the base  110  is in the folded condition. The snap-fit connector components  180   a - b  may include a mating tongue or extension that mates with a groove or detent. When the user is ready to adjust the anchor device  100  to the non-folded condition, the snap-fit connector components  180   a - b  can be manually separated by application of a low separation force from the user. The U-shaped clip device  160  can be readily removed from the base  110  by sliding the clip device  160  in a lateral direction generally perpendicular to the fold line  113  of the anchor device  100 . 
     In these embodiments illustrated in  FIGS. 8-9 , the anchor device  100  may be provided in a sterile package while being retained in the folded condition by one or more of the clip device  160  or  170  or the snap-fit connector components  180   a - b . From there, a user can readily remove the device  100  and begin to insert the subcutaneous tines  145   a - b  through the skin penetration point  132  without being required to manually adjust the base  110  to the folded condition. 
     A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the scope of the invention. Accordingly, other embodiments are within the scope of the following claims.