Abstract:
A system and associated method for manipulating tissues and anatomical or other structures in medical applications for the purpose of treating diseases or disorders or other purposes. An implant for attachment of soft tissue to bone, an insertion tool for anchoring suture anchors to bone, and a method for anchoring a suture anchor to bone.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of copending U.S. patent application Ser. No. 12/791,805, entitled Integrated Handle Assembly for Anchor Delivery System, filed on Jun. 1, 2010, which is a continuation-in-part of U.S. patent application Ser. No. 11/492,690, now U.S. Pat. No. 7,896,891, entitled Apparatus and Method for Manipulating or Retracting Tissue and Anatomical Structure, filed on Jul. 24, 2006, which is a continuation-in-part of copending U.S. patent application Ser. No. 11/318,246, now U.S. Pat. No. 7,645,286, entitled Devices, Systems and Methods for Retracting, Lifting, Compressing, Supporting or Repositioning Tissues or Anatomical Structures, filed on Dec. 22, 2005, which is a continuation-in-part of copending U.S. patent application Ser. No. 11/134,870, now U.S. Pat. No. 7,758,594, entitled Devices, Systems and Methods for Treating Benign Prostatic Hyperplasia and Other Conditions, filed on May 20, 2005, the entire disclosures of which are expressly incorporated herein by reference. 
         [0002]    This application claims priority to and the benefit of pending U.S. Provisional Application No. 61/707,752 filed Sep. 28, 2012 entitled Suture Anchoring Devices and Methods for Use, which application is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates to a surgical implant for attachment of soft tissue to bone, an insertion tool for anchoring suture anchors to bone, and a method for anchoring a suture anchor to bone. 
         [0004]    It is often necessary to attach soft tissue to bone, for example, to attach ligament tissue to bone tissue. Loss of integrity in bone tissue, for example, a ligament of a human rotator cuff, as well as recurrent dislocation of the shoulder, may result in abnormal kinematics of the shoulder. This may cause progressive weakness of the shoulder and, in some circumstances, severe dysfunction of the shoulder and progressive degenerative joint changes. Accordingly, procedures have been developed to repair, for example, the rotator cuff, to prevent debilitating loss of function and to restore more physiologic biomechanics. However, these conventional procedures may require invasive surgical procedures, which may lead to increased complications and increased morbidity. 
         [0005]    Many of the early suture anchors were operable to be screwed into the bone. However, to properly secure such an anchor, the bone had to be first prepared by a separate tapping step (i.e., a pre-drilling step). In an effort to eliminate the initial tapping step, push-in type anchors were developed. The effectiveness of push-in type anchors may be measured by their ability to reliably set in all bone types, the size of the anchor, and the effectiveness of insertion tools for protecting suture threads while inserting the anchors into bone. 
         [0006]    With respect to push-in type suture anchors, the insertion tool, the suture implant, and the method of insertion should act to consistently and reliably set the implant in a variety of bone types. For this purpose, the implant should be designed as small as possible to limit the amount of foreign substance in the body, and should have features configured to consistently set the anchor into bone. 
         [0007]    Due to the limitations of the conventional suture anchors, delivery instruments, and methods described above, a need exists for a simple, strong, and reliable suture anchor, as well as a technique for fixating suture to bone. 
         [0008]    Furthermore, a need exists for a push-in type suture anchor and delivery instrument that protects the sutures during insertion of the anchor into bone. 
         [0009]    Effective tissue anchors require a contradictory combination of small size for ease of delivery and large size for substantial tissue purchase. 
         [0010]    Other applications for tissue anchors include manipulating or retracting tissues and anatomical or other structures within the body of human or animal subjects for the purpose of treating diseases or disorders. One example of a condition where it is desirable to lift, compress or otherwise remove a pathologically enlarged tissue is Benign Prostatic Hyperplasia (BPH). 
         [0011]    The present disclosure addresses these and other needs. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    Embodiments of the invention include a suture anchor comprising a distal portion configured to penetrate tissue, a proximal portion comprising a wing, and a body portion comprising a telescoping portion configured to extend upon placement within tissue. 
         [0013]    Embodiments of the invention include a suture anchor comprising a distal portion configured to penetrate tissue, a proximal portion comprising a wing, and a body portion comprising a plurality of nested segments configured to separate and increase the effective volume of the suture anchor upon placement within tissue. 
         [0014]    Embodiments of the invention include a suture anchor comprising a distal portion configured to penetrate tissue, a proximal portion comprising a wing, and a body portion comprising an expandable portion configured to increase the effective volume of the suture anchor upon placement within tissue. 
         [0015]    Embodiments of the invention include a method of placing a suture anchor comprising driving the suture anchor having an asymmetric cross-section through a tissue surface and into a tissue volume, wherein an asymmetric hole is formed in the tissue surface, rotating the suture anchor about a longitudinal axis of the suture anchor, pivoting the suture anchor such that its longitudinal axis is comparatively less perpendicular to the tissue surface than when the suture anchor was driven into tissue, and backfilling the hole with a material capable of providing a physical barrier to the suture anchor. In some embodiments the material is a plug and in some embodiments the material is a flowable substance. 
         [0016]    Embodiment of the invention include a method of treating a prostate including penetrating the prostatic capsule with a suture anchor configured to increase its effective volume upon placement in tissue. 
         [0017]    Other features and advantages of the present disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         [0018]      FIGS. 1-5  depict suture anchors of the prior art and methods of insertion. 
           [0019]      FIG. 6  illustrates a method for improving the placement of suture anchors and elements related to such improvements, according to embodiments of the invention. 
           [0020]      FIGS. 7 and 8  illustrate nesting suture anchors according to embodiments of the invention. 
           [0021]      FIG. 9  illustrates a suture anchor with telescoping segments according to embodiments of the invention. 
           [0022]      FIG. 10  illustrates an alternative embodiment of a telescoping suture anchor according to embodiments of the invention. 
           [0023]      FIGS. 11 and 12  illustrate an embodiment in which the suture anchor includes an expanding element according to embodiments of the invention. 
           [0024]      FIGS. 13A and 13B  illustrate views of a narrowed and a widened prostatic urethra, respectively. 
           [0025]      FIG. 14  illustrates a method for reducing narrowing in a prostatic urethra using suture anchors according to embodiments of the invention. 
           [0026]      FIG. 15  illustrates another method for reducing narrowing in a prostatic urethra using suture anchors according to embodiments of the invention. 
           [0027]      FIG. 16  illustrates multiple suture anchors deployed within the prostatic lobe or on the outer surface of the prostatic capsule of a prostatic lobe according to embodiments of the invention. 
           [0028]      FIG. 17  illustrates further alternate embodiments in which multiple suture paths through a prostatic lobe are used to reduce the narrowing of the prostatic urethra according to embodiments of the invention. 
           [0029]      FIG. 18  illustrates yet another embodiment in which suture anchors are used to reduced the narrowing of the urethra according to embodiments of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    Before the present devices and methods are described, it is to be understood that this invention is not limited to particular embodiments described, as such may vary from the specific embodiments. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims. 
         [0031]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. 
         [0032]    Short summaries of certain terms are presented in the description of the invention. Each term is further explained and exemplified throughout the description, figures, and examples. Any interpretation of the terms in this description should take into account the full description, figures, and examples presented herein. 
         [0033]      FIG. 1  illustrates a side view of a suture anchor of the prior art and  FIG. 2  illustrates a back view of the same prior art suture anchor. Anchor  100  includes a conical distal portion  110 , body  120 , and wing  130 . Conical distal portion  110  is configured to penetrate tissue and in particular bone tissue. Body  120  includes holes  122  through which suture may be threaded. Wing  130  is connected to body  120 .  FIG. 2  illustrates the back view of suture anchor  108  and depicts the relationship among fin  130 , body  120 , and conical distal portion  110 . 
         [0034]      FIG. 3  illustrates a prior art method for inserting suture anchor  100  into tissue and in particular bone tissue.  FIG. 3  depicts sutures  180  connected through holes  122 . Suture anchor  100  is depicted as being driven through cortical layer  250  of bone tissue and into the comparatively softer cancellous layer  200  of bone tissue. The conical distal portion of the suture anchor facilitates placement of the suture anchor. 
         [0035]      FIG. 4  illustrates a further step in the prior art method of inserting suture anchor  100  into bone tissue in which the proximal end of the suture anchor has penetrated beyond the cortical layer  250  of bone tissue and is completely within the cancellous layer  200  of bone tissue.  FIG. 5  illustrates a further step in the method of placing prior art suture anchors in which the anchor pivots with respects to the axis of its entry into bone tissue after having been rotated such that the wing is positioned in such a way as to prevent the suture anchor from backing out through the hole left in the cortical layer of bone tissue. 
         [0036]    When the suture anchor is advanced through the cortical layer of bone, the wing of the anchor leaves a radial slot through the surface of the cortical layer of bone. The final position of the suture anchor within the bone tissue relies on friction and the three-step installation (that is, the axial penetration of the anchor into tissue, rotation of the anchor about its longitudinal axis to misalign the wing with the radial slot in the cortical layer of bone, and the pivoting or toggling of the anchor to increase its “footprint” within the cancellous layer of bone such that it is wider than the entry hole in the cortical layer) to maintain the anchor body parallel relative to the cortical layer. 
         [0037]    According to certain embodiments of the present invention, the positioning and permanence of the suture anchor is improved such that the suture anchor will stay in the final position and not back out of the bone tissue. 
         [0038]      FIG. 6  illustrates a perspective view of cortical bone layer  250  after a suture anchor has been driven through cortical bone layer  250 .  FIG. 6  depicts the surface of cortical bone layer  250  as including keyhole  280 . Keyhole  280  roughly corresponds to the cross section of the suture anchor, including the wing of the suture anchor (similar to the back view of the suture anchor depicted in  FIG. 2 ). In prior art suture anchors, the suture anchor is rotated and pivoted to prevent it from backing out of keyhole  280 . 
         [0039]    According to certain embodiments of the present invention, after deploying the suture anchor into its position within the cancellous bone, and optionally after rotating and pivoting the suture anchor, keyhole  280  is backfilled with a biocompatible substance. The biocompatible substance is capable of swelling, hardening, or otherwise providing an additional mechanical barrier that helps prevent the suture anchor from backing out of keyhole  280 . Certain bone cements, such as, but not limited to, polymethyl methacrylate, can be used to backfill keyhole  280 . 
         [0040]    In some embodiments, the space in the cancellous bone around the suture implant may also be filled with the biocompatible substance that provide this additional mechanical barrier. In some embodiments, it may be advantageous to apply the biocompatible substance prior to rotating the suture anchor and/or prior to pivoting the suture anchor. In such embodiments, applying the biocompatible substance prior to rotating and/or pivoting the suture anchor can help spread, mix, or commingle the biocompatible substance with the suture anchor, in the space around the suture anchor, and with the cancellous bone tissue near the suture anchor. 
         [0041]    In some embodiments, it may be advantageous to apply the biocompatible substance after the suture anchor has been rotated and pivoted into a desired position. In such embodiments, applying the biocompatible substance after the suture anchor is in its desired position may allow for substantially complete backfilling of keyhole  280  and/or the space around the suture anchor. 
         [0042]    According to certain embodiments, the biocompatible substance is capable of flowing or has a sufficiently low viscosity such that it can be applied to occupy the space in keyhole  280  and/or the space around the suture anchor. Liquids and gels, including two-part liquids and gels that thicken and or cure when mixed, may have suitable flow characteristics. 
         [0043]    The biocompatible substance filling the space around the suture anchor and in the keyhole provides additional strength to the suture anchor and assurance that it will not back out. Embodiments of the invention improve on current suture anchor technologies that rely on friction and/or a narrow installation pathway. If installation of the suture anchor is difficult and the space needed to rotate the suture anchor becomes larger than desired, the prior art suture anchor alone may not have a sufficient footprint for the suture anchor to remain in place. Further, the quality of the tissue into which the suture anchor is implanted may be low and may not be sufficiently strong to hold the anchor in place. The biocompatible substance can provide additional strength in both of these situations. 
         [0044]    The biocompatible substance may be delivered with the same tool that helps insert and install the suture anchor or it may be delivered with a separate tool. 
         [0045]      FIG. 6  depicts plug  300 , which has a shape similar to that of keyhole  280  according to certain embodiments. Plug  300  includes holes through which suture  180  may be threaded. Plug  300  may be used to fill some or all of keyhole  280  after the suture anchor has been placed in the desired position. In certain embodiments, the biocompatible substance may be used to further seal plug  300  into place. In some embodiments, the biocompatible substance is applied to the area around the suture anchor prior to the plug  300  being placed within the keyhole  280 . In certain embodiments, the biocompatible substance is applied to plug  300  after it has been placed within keyhole  280 . 
         [0046]    Other embodiments of the invention further improve upon conventional suture anchors. 
         [0047]      FIG. 7  illustrates an embodiment of the invention in which the suture anchor includes at least two nested anchor segments.  FIG. 7  depicts suture anchor  400  as including two anchor segments  425  and  475 . Distal anchor segment  425  includes conical distal portion  410 , distal body  420 , and distal wing  430 . Distal anchor segment  425  also includes hole  422  through which suture  180  is threaded. Proximal anchor segment  475  includes proximal body  470  and proximal wing  490 . Proximal anchor segment  475  includes hole  472  through which suture  180  is threaded. Distal anchor segment  425  and proximal anchor segment  475  include complementary ends configured to allow the anchor segments to nest together to form a substantially rigid suture anchor. When the anchor segments are nested together, suture anchor  400  can be driven into tissue more easily than when the anchor segments are separated.  FIG. 7  depicts one nesting configuration in which the proximal anchor segment  475  has a pointed distal end and distal anchor segment  425  has an inverted pointed shape on its proximal end. It is understood that other complementary shapes for the nesting ends of the anchor segments are within the scope of the invention. 
         [0048]      FIG. 8  illustrates a nested suture anchor in which the nested segments are separated. When anchor segments  425  and  475  are separated, the footprint of the suture anchor is larger than when they are nested and such larger footprint provides improved anchoring within the tissue as compared to conventional anchors. 
         [0049]    According to embodiments of the invention, the tissue anchor includes a plurality of segments, which are stacked in an in-line configuration for delivery to a site within the body. Each segment is connected to a single connecting member. On delivery into the target site the connecting member is tensioned and the segments separate. The separate segments create a volume that is commingled with local tissue and resists pulling through the delivery hole. Alternative versions of this embodiment include a nesting design of the individual segments, separate connecting members, or separate filaments of the same connecting member. 
         [0050]      FIG. 9  illustrates a suture anchor with telescoping segments. Distal segment  525  and proximal segment  575  are depicted in  FIG. 9  in a collapsed configuration in which central segment  550  is substantially within an interior space of each of distal segment  525  and proximal segment  575 . Central segment  550  is configured to allow distal segment  525  and proximal segment  575  to extend to a greater length. The telescoping segments may be spring biased to extend when under tension from the sutures. Further, the telescoping segments may be drawn into an extended configuration when under tension from the sutures. 
         [0051]    In another embodiment, connecting members or separate filaments of the same connecting member are individually attached to each telescoping segment of the suture anchor. The attachment points for the filaments or connecting members are positioned on the telescoping segments such that tension in the filaments exerts a length-expanding force on the telescoping elements. 
         [0052]      FIG. 10  illustrates an alternative embodiment of a telescoping suture anchor. Suture anchor  600  includes proximal segment  675  and distal segment  625 . Central pivoting connector  650  includes pivot point  652  about which the two segments can pivot. The combination of a central pivoting connector and the telescoping segments provides suture anchor  600  with a larger footprint within tissue when implanted. 
         [0053]    In the telescoping environments, a locking mechanism can help maintain the extended configuration of the telescoped segments. 
         [0054]    In certain embodiments presented herein, the comparatively short length of the tissue anchor facilitates delivery through curved trajectories. Upon delivery into tissue, the suture anchors expand in effective length and/or volume. This provides a large surface area that helps prevent the anchor from returning through the delivery hole. 
         [0055]      FIGS. 11 and 12  illustrate an embodiment in which the suture anchor includes an expanding element. Suture anchor  700  includes flexible legs  750  that are positioned about a cutout in the body of suture anchor  700 . During delivery, a rod or similar device would be inserted into the anchor. To set the anchor, the rod would be removed and tension would be applied to the suture, collapsing the flexible legs. In this configuration, the suture anchor expands in effective volume and helps prevent the anchor from returning through the delivery hole. 
         [0056]    Suture anchors disclosed herein are suitable for use in various parts of the anatomy. For example, such suture anchors can be used to displace or compress one or more lobes of the prostates gland to reduce or eliminate symptoms of benign prostatic hyperplasia. 
         [0057]      FIGS. 13A and 13B  depict urethra  2  and prostatic lobes  5 . In  FIG. 13A , lobes  5  are narrowing the width of urethra  2 , and such narrowing produces symptoms such as urinary hesitancy, frequent urination, painful urination, increased risk of urinary tract infections, and urinary retention.  FIG. 13B  illustrates the prostatic lobes of  FIG. 13A  after the narrowing of the urethra has been reduced. Suture anchors according to embodiments described herein can be used to displace or compress the prostatic lobes and/or reduce the narrowing of the urethra. 
         [0058]      FIG. 14  illustrates a method for reducing narrowing in urethra  2  using suture anchors  800  according to embodiments described herein. In  FIG. 14 , a single suture anchor  800  has been deployed such that the suture anchor  800  is position on the outer surface of the prostatic capsule  8 , which is a membrane that surrounds and encloses the prostate gland. Suture anchor  800  can be passed through prostatic lobe  5  and through prostatic capsule  8  to be deployed. Suture anchor  800  can be passed through a pre-existing delivery track made by a penetrating device, such as a trocar or a needle. Or, suture anchor  800  can be carried by the penetrating device to the outside of prostatic capsule  8 . For example, the anchor can be carried within a hollow needle, can ride on the outside of a trocar, or can be delivered by equivalent methods. In certain embodiments, suture anchor  800  is sufficiently sharp such that it can be the penetrating tip of a penetrating delivery device. That is, suture anchor  800  can ride towards the end of a pusher, and the pusher can be retracted when the suture anchor reaches the outside of prostatic capsule  8 . Suture anchor  800  is attached to suture  180 , and suture  180  is carried along with suture anchor  800  during deployment. Suture  180  traverses prostatic lobe and terminates at urethral tab  850 . Urethral tab  850  may be attached to suture  180  prior to or after suture anchor  800  is deployed to the outer surface of prostatic capsule  8 . 
         [0059]      FIG. 15  illustrates another method for reducing narrowing in urethra  2  using suture anchors  800  according to embodiments described herein. The right prostatic lobe  5   r  is depicted with two different anchoring methods. In one method, a single suture anchor  800  is deployed within the prostatic lobe rather than outside the prostatic capsule as depicted in  FIG. 14 . Like the embodiments depicted in  FIG. 14 , suture anchor  800  is connected to urethral tab  850  via suture  180 . Suture anchor  800  can be passed through a pre-existing delivery track made by a penetrating device, such as a trocar or a needle. Or, suture anchor  800  can be carried by the penetrating device to a position within prostatic lobe  5   r.  For example, the anchor can be carried within a hollow needle, can ride on the outside of a trocar, or can be delivered by equivalent methods. In certain embodiments, suture anchor  800  is sufficiently sharp such that it can be the penetrating tip of a penetrating delivery device. That is, suture anchor  800  can ride towards the end of a pusher, and the pusher can be retracted when the suture anchor reaches delivery position within prostatic lobe  5 . 
         [0060]      FIG. 15  illustrates embodiments in which more than one suture anchor  800  is connected to a single urethral tab  850 . In one embodiment, two suture anchors  800  are deployed within prostatic lobe  5   r.  The suture anchors  800  can be deployed using the needle or trocar methods, or their equivalents, described herein. Similarly, the suture anchors  800  can be delivered using a pre-existing penetration track or using a pusher having a suture anchor  800  as its penetration tip. Suture  180  connects both suture anchors  800  to urethral tab  850  and to each other. 
         [0061]    While  FIG. 15  depicts suture anchors  800  in the same plane, of course prostatic lobe  5   r  is a three-dimensional structure and suture anchors  800  need not be in the same plane. Further, each suture anchor  800  maybe connected via separate sutures  180  to a single urethral tab  850 . 
         [0062]      FIG. 15  illustrates another embodiment in which multiple suture anchors  800  are deployed to reduce urethral narrowing. In this embodiment, one suture anchor  800  is deployed to the outer surface of prostatic capsule  8  and one suture anchor  800  is deployed within prostatic lobe  51 . Suture  180  connects suture anchors  800  to urethral tab  850  and each other. 
         [0063]      FIG. 16  illustrates multiple suture anchors  800  deployed within the prostatic lobe  51  or on the outer surface of the prostatic capsule  8  of prostatic lobe  5   r.  The multiple anchors are connected by suture  180 , and in these embodiments suture  180  passes across the urethral side of the prostatic lobes  5   r  and  51 . Similar to the embodiments in  FIG. 15 , suture anchors  800  may be placed within the prostatic lobe or on the outer surface of the prostatic capsule using a penetrating member. In certain embodiments, suture  180  is connected to both anchors prior to deployment. Suture  180  may be fixed to the first suture anchor  800  that is deployed and coupled to the second suture anchor  800  such that suture  180  may be tensioned. As with other embodiments disclosed herein, suture  180  can be tensioned using the delivery device. Further, an optional suture lock  860  can be used to lock the tensioned suture in place. As with other embodiments disclosed herein, a cutting device may be used to cut the free end of the suture after it has been tensioned and secured to a urethral tab or a suture lock. Further, a knot can be used in addition to or instead of a suture lock of urethral tab. 
         [0064]    According to certain embodiments, suture lock  860  can be a ferrule, which can be crimped either on the suture on the urethral side of the prostatic lobe or at the joint of the urethra and suture. In the case where the ferrule is crimped to the suture on the urethral side of the prostatic lobe, the ferrule can act as a urethral tab. 
         [0065]      FIG. 17  depicts further alternate embodiments in which multiple suture paths through a prostatic lobe are used to reduce the narrowing of the urethra. Prostatic lobe  5   r  depicts two suture anchors  800  that each have two sutures  180  extending from them to connect with a total of four urethral tabs on the urethral side of the prostatic lobe  5   r.  Such multiple suture strands can be tensioned and cut as described herein or using equivalent methods. Of course, the method is not limited to two suture strands per suture anchor.  FIG. 17  also depicts an embodiment in a single suture  180  traverses prostatic lobe  51  multiple times before being secured on the urethral side of prostatic lobe  51 . Suture  180  can be secured using the methods and devices disclosed herein, such as knots, ferrules, tab, or their equivalents. 
         [0066]      FIG. 18  depicts yet another embodiment in which suture anchors  800  are used to reduced the narrowing of the urethra. In this embodiment, multiple suture anchors  800  are delivered to the inside surface of the prostatic capsule  8  and then connected to the pelvic bone  15 . Sutures  180  can be tensioned such that the narrowing of the urethra is reduced by displacing the prostatic lobes away from each other. Suture  180  can be connected to pelvic bone by tying the ends of the sutures off one the bone or on connectors (such as k-wires) that are in turn connected to the pelvic bone. According to these embodiments, suture anchors can be placed using minimally invasive surgical techniques of the lower abdomen, in contrast to the trans-urethral approach used in other embodiments disclosed herein. 
         [0067]    Certain embodiments disclosed herein include multiple suture anchors delivered to prostatic tissue. Such suture anchors can be delivered in series such that each anchor is connected along one or more segments of suture to the next anchor. Alternately, multiple anchors can each have a discrete segment of suture that is then joined to the next anchor in the series. Sutures as used herein includes conventional surgical suture as well as other connectors of varying rigidity, elasticity, and flexibility. 
         [0068]    Advantageously, the volume-occupying characteristics of many of the improved suture anchors described herein are useful in the embodiments designed to be secured in or on prostatic tissue. For example, in the embodiments using multiple anchors in a prostatic lobe in which a second anchors “follows” a first anchor into tissue, the volume-occupying properties of such improved anchors can allow the second anchor to hold securely in tissue. 
         [0069]    While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.