Patent ID: 12251100

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.

With initial reference toFIG.1, a tissue fixation device according to the present teachings is generally illustrated at reference numeral10. Although the tissue fixation device10is generally described herein as configured to secure tissue to bone, the tissue fixation device10can also be used to, for example, secure two bones or bone portions together, as well as two tissues or tissue portions together. The tissue fixation device10generally includes a soft or flexible anchor12and a self-locking construct14.

The anchor12includes a first anchor end20and a second anchor end22, which is opposite to the first anchor end20. The anchor12can be an elongate member having a sleeve or tubular configuration. The anchor12thus defines a first opening24at the first anchor end20, and defines a second opening26at the second anchor end22. The anchor12further defines an anchor internal passage28extending between the first opening24and the second opening26. At the first anchor end20is a first end surface30, and at the second anchor end22is a second end surface32. As described herein, the first and the second end surfaces30and32are configured to abut an interior surface of cortical bone in order to facilitate retention of the tissue fixation device10within a bone hole.

In place of the anchor10, any suitable soft or hard anchor can be used, such as any of the soft or hard anchors described in U.S. application Ser. No. 13/098,927 (“'927 Application”) titled “Method and Apparatus for Soft Tissue Fixation,” filed on May 2, 2011, and assigned to Biomet Sports Medicine, LLC, which is incorporated herein by reference. In place of the anchor10can also be any of the anchors described in U.S. Pat. No. 8,562,647 ('647 Patent”) titled “Method and Apparatus for Securing Soft Tissue to Bone,” issued on Oct. 22, 2013, and assigned to Biomet Sports Medicine, LLC, which is incorporated herein by reference. The anchor12can be made of any suitable material, such as resorbable or non-resorbable materials, including braided suture, sponges, and sponge-like materials, including braided suture, sponges, and sponge-like materials in solid form, perforated materials, woven/braided from biocompatible materials or fibers, such as, for example, polymer, polyester, polyethylene, cotton, silk, or other natural or synthetic materials.

The self-locking construct14can be made of any suitable material, such as a flexible material including suture, such as a suture strand50. When the construct14is made of suture, any suitable suture can be used. For example, a braided hollow-core suture strand50can be used. Any suitable braided suture can be used, such as any of the braided sutures disclosed in U.S. patent application Ser. No. 12/915,962 titled “Method and Apparatus for Securing Soft Tissue to Bone,” which was filed on Oct. 29, 2010, published as Publication No. 2011/0098727 on Apr. 28, 2011, and is assigned to Biomet Sports Medicine, LLC. Although the construct14can be made of any suitable material in addition to suture, the construct14will generally be described herein as a construct.

The construct14generally includes a first end52and a second end54of the suture strand50. The suture strand50is arranged to provide a self-locking, first adjustable loop56and a self-locking, second adjustable loop58. The suture strand50includes a portion60between the first end52and the second end54. The portion60itself includes a first end62and a second end64. The portion60defines a passageway or internal passage portion66extending between the first end62and the second end64of the portion60.

As illustrated inFIG.1, portions of the suture strand50extend through the internal passage portion66. The suture strand50passes through the internal passage portion66a first time to define the first adjustable loop56, and a second time to define the second adjustable loop58. The internal passage portion66can be any suitable passage through the suture strand50, through which portions of the suture strand50can pass to define the first and the second adjustable loops56and58, such as the passage portions described in the ′927 Application and the ′647 Patent, which are incorporated herein by reference.

Slidably mounted to the first adjustable loop56is a first suture tail70a. Slidably mounted to the second adjustable loop58is a second suture tail70b. The first suture tail70ais similar to the second suture tail70b. In order to facilitate differentiation between the first suture tail70aand the second suture tail70b, such as by a surgeon in the operating room, the first suture tail70aand the second suture tail70bcan include any suitable distinguishing identifiers. For example, the first and second suture tails70aand70bcan be provided with different colors, different visual patterns, different indicia (such as different striping) different sizes (such as different lengths or widths), or different materials.

The first suture tail70aand the second suture tail70bcan each be made of any suitable material, such as the same material as the suture strand50, or any of the alterative materials of the suture strand50described above. Features in common between the first and second suture tails70aand70bare illustrated and described using similar reference numbers, but reference numbers of the first suture tail70ainclude the suffix “a,” and reference numbers of the second suture tail70binclude the suffix “b.” Because the first suture tail70ais similar to the second suture tail70b, the detailed description below of the first suture tail70adescribes the second suture tail70bas well.

The first suture tail70aincludes a first end72aand a second end74a. The first end72ais opposite to the second end74a. At the first end72ais a locking portion76a. Extending from the locking portion76ato the second end74ais an elongated tail portion78a. The locking portion76aincludes a portion80a, which defines a passageway or passage portion86a. The passage portion86aextends between a first opening82aand a second opening84aformed between suture braids of the first suture tail70a. The first adjustable loop56extends through the passage portion86a, thereby coupling the first suture tail70ato the suture strand50. Similarly, the second suture tail70bcan be arranged such that the suture strand50of the second adjustable loop58extends through passageway86bdefined by the second suture tail70bat the locking portion76b.

As further described herein, the construct14is configured such that upon pulling the first end52of the suture strand50, a portion of the suture strand50within the internal passage portion66will be pulled out through the first sleeve end62thereof, thus closing the first adjustable loop56, and reducing the size thereof. Similarly, pulling the second end54pulls a portion of the suture strand50out of the internal passage portion66at the second sleeve end64, in order to reduce the size of, and close, the second adjustable loop58. As the first and second ends52and54are pulled, the first and second adjustable loops56and58are tensioned, thus causing the internal passage portion66to collapse onto portions of the suture strand50extending therethrough, thereby restricting movement of the suture strand50through the sleeve internal passage66, and thus locking the first and second adjustable loops56and58to prevent them from reopening. In this manner, the first and the second adjustable loops56and58are self-locking.

Prior to the tissue fixation device10being implanted, the first and second adjustable loops56and58can be provided in a retracted or closed position, such that the first and second adjustable loops56and58are small, which can advantageously reduce any possibility of tangling of the first and second adjustable loops56and58. In order to open the first and second adjustable loops56and58, the first suture tail70acan be pulled at the second end74a, thereby pulling a portion of the suture strand50out from within the internal passage portion66at the second sleeve end64. The second adjustable loop58can be opened by pulling the second suture tail70b, such as at the second end74b, in order to pull a portion of the suture strand50out from within the internal passage portion66at the first sleeve end62. Because the first and the second adjustable loops56and58have not yet been tensioned, such as when closed against tissue120to secure the tissue120to bone110as described herein, and the anchor12has not yet collapsed as illustrated in FIG.7for example, the first and the second adjustable loops56and58can be opened in this manner.

With reference toFIG.2, the tissue fixation device10is illustrated implanted in bone110. The bone110includes a relatively soft inner cancellous bone layer112, and a relatively hard outer cortical bone layer114. An outer surface116of the bone110is at a side of the cortical bone layer114opposite to the cancellous bone layer112. Formed within the bone110is a bone hole118. The bone hole118is formed through the outer surface116, through the outer cortical bone layer114, and into the cancellous bone layer112. The bone hole118can be formed in any suitable manner, such as with a suitable drill or impactor, or any other suitable bone cutting device.

The tissue fixation device10is arranged such that the anchor12is seated in the bone hole118. The anchor12protrudes slightly into the cancellous bone layer112proximate to the cortical bone layer114at the first and second anchor ends20and22thereof. The first and the second end surfaces30and32abut the cortical bone layer114at a side thereof opposite to the outer surface116and adjacent to the cancellous bone layer112. As illustrated inFIG.2, the first and second adjustable loops56and58are made smaller or closed, so as to reduce any possibility of tangling, as described above. After one or more of the tissue fixation devices10are implanted in bone, they may be used to secure tissue120to bone110, as will now be described.

With reference toFIG.3, two of the tissue fixation devices10are illustrated implanted in the bone110in the same manner as illustrated inFIG.2. The tissue fixation devices10can be used to secure tissue120to the bone110. The two tissue fixation devices10are illustrated as first tissue fixation device10aand second tissue fixation device10b. Only the first tissue fixation device10aneed be used to secure tissue120to bone110. To enhance fixation of the tissue120to bone110, however, additional tissue fixation devices10can be used, such as the second tissue fixation device10bor yet additional tissue fixation devices10, as described herein.

The second tissue fixation device10bis substantially similar to, or the same as, the first tissue fixation device10a. The second tissue fixation device10bincludes first and second suture tails70cand70d, which are similar to, or the same as, the first and second suture tails70aand70bof the first tissue fixation device10a. The first and second adjustable loops of the second tissue fixation device10bare illustrated at reference numerals56band58brespectively.

After the tissue fixation devices10aand10bare initially seated in the bone hole118as illustrated inFIG.2, their suture tails70a,70b,70c, and70dare pulled through the tissue120, as illustrated inFIG.3. The tails70a,70b,70c, and70dand the loops56a,58a,56b, and58bare then arranged as described below and illustrated inFIGS.4-7to apply pressure against the tissue120and secure the tissue120against the outer bone surface116.

FIGS.4-7illustrate arrangement of the first and second tails70aand70b, and the first and second loops56aand56b, of tissue fixation device10(illustrated inFIG.3at reference number10ato distinguish the second tissue fixation device10b) to retain the tissue120against the outer bone surface116. The method ofFIGS.4-7applies to both the first and second tissue fixation devices10aand10bofFIG.3.

After the tissue fixation device10has been seated in the bone hole118as illustrated inFIG.2, the first and second suture tails70aand70bare pulled through the tissue120, thus pulling the first and second adjustable loops56and58through the tissue120as well, as initially set forth above. The first and second suture tails70aand70b, and the first and second adjustable loops56and58associated therewith, are pulled through spaced apart areas of the tissue120, thus leaving a portion of the tissue120between the first and second adjustable loops56and58.

With reference toFIG.4, after the first and second adjustable loops56and58are pulled through the tissue120using the first and second suture tails70aand70b, the first and second adjustable loops56and58can be coupled together and cinched down against the tissue120in order to secure the tissue against the outer surface116of the bone110. For example, the second end74aof the first suture tail70acan be pulled through the second adjustable loop58in order to pull the first suture tail70athrough the second adjustable loop58, and pull the first adjustable loop56such that a portion thereof extends through the second adjustable loop58, as illustrated inFIG.5.

With reference toFIG.6, the second adjustable loop58is cinched down onto the first adjustable loop56by pulling on the second end54. As the second end54is pulled, the second adjustable loop58will reduce in size and pull the first adjustable loop56against the tissue120, and affix the tissue120to the outer surface116of the bone110. With reference toFIG.7, after the size of the second adjustable loop58is reduced, the size of the first adjustable loop56is reduced by pulling the first end52of the suture strand50. As the first adjustable loop56is reduced in size, the first suture tail70awill abut the second suture tail70band/or the second adjustable loop58. As the first end52is pulled further, the first suture tail70aand/or the first adjustable loop56will pull the second suture tail70band the second adjustable loop58further against the tissue120, in order to further secure the tissue120to the outer surface116of the bone110. As the first and second ends52and54are pulled as illustrated inFIGS.6and7respectively, the first and second adjustable loops56and58are tensioned, thus causing the internal passage portion66to collapse onto portions of the suture strand50extending therethrough, thereby restricting movement of the suture strand50through the internal passage portion66, and thus locking the first and second adjustable loops56and58to prevent them from reopening. The anchor12will then deform as illustrated inFIG.7to lock the anchor12in the bone hole118.

AlthoughFIGS.3-7illustrate coupling together first and second adjustable loops56and58from the same tissue fixation device10, various other configurations and arrangements are contemplated. For example, and with reference toFIG.8, in applications where both the first tissue fixation device10aand the second tissue fixation device10bare used, the first suture tail70aof the first tissue fixation device10acan be coupled to the second tissue fixation device10b. This can be done by inserting the first suture tail70athrough the second adjustable loop58bof the second tissue fixation device10b, which will couple the first adjustable loop56aof the first tissue fixation device10ato the second adjustable loop58bof the second tissue fixation device10bonce the second adjustable loop58bis cinched down onto the first adjustable loop56ain the same manner described above. Similarly, the second adjustable loop58bof the second tissue fixation device10bcan be coupled to the first adjustable loop56aof the first tissue fixation device10aby closing the second adjustable loop58aonto the first adjustable loop56bas described above. Use of both the first and second tissue fixation devices10aand10bto fix the tissue120to the bone110advantageously retains a greater portion of the tissue120against the bone110, thereby distributing load against the tissue120and decreasing any possibility of the suture strands50cutting through the tissue120.

With reference toFIG.9, a third tissue fixation device10ccan be used to affix the tissue120to the bone110. The third tissue fixation device10ccan be similar to, or the same as, the first and second tissue fixation devices10aand10b. The third tissue fixation device10ccan be implanted in the bone110spaced apart from the tissue120, and beyond a distal end122thereof.

The third tissue fixation device10ccan be coupled with the first and second tissue fixations device10aand10bin any suitable manner. For example, the first suture tail70aof the first tissue fixation device10acan be inserted through a first adjustable loop56cof the third tissue fixation device10cin order to couple the first adjustable loops56aand56ctogether after the first adjustable loop56cis cinched down onto the first adjustable loop56aof the first tissue fixation device10a. The second adjustable loop58cof the third tissue fixation device10ccan be coupled to the second adjustable loop58bof the second tissue fixation device10b, such as by inserting the second suture tail70dthrough the second adjustable loop58cand closing the second adjustable loop58conto the second adjustable loop58b. The first and second tissue fixation devices10aand10bcan be connected by coupling the second adjustable loop58aof the first tissue fixation device10awith the first adjustable loop56bof the second tissue fixation device10bas described above. Thus, the suture tails70a-70fare coupled to loops56a-56cand58a-58cof neighboring tissue fixation devices10a-10cin order to chain the tissue fixation devices10a-10ctogether. Including the third tissue fixation device10cin the arrangement ofFIG.9advantageously secures the distal end122of the tissue120to the outer surface116of the bone110.

With reference toFIGS.10and11, an additional soft or flexible anchor90may be added to the tissue fixation device10in order to provide additional fixation of the tissue120. The anchor90may be similar to the anchor12, or any other suitable soft or flexible anchor that is deformable in order to be retained in the bone hole124. The anchor90can be added to the tissue fixation device10in any suitable manner, such as with a threader130illustrated inFIG.10. The threader130includes a loop portion132at a distal end of elongated rods134. The anchor90is initially seated on the elongated rods134such that the elongated rods134extend through the anchor90.

The anchor90can be attached to the first suture tail70aby first passing the tail portion78athereof into the loop portion132, and folding the tail portion78aover the loop portion132. The anchor90is then slid over the tail portion78athat is folded over the loop portion132, and onto the first suture tail70a. The first suture tail70aand the first adjustable loop56coupled thereto are then pulled through the anchor90so that the anchor90is seated on the first adjustable loop56. The anchor90can be implanted in the bone110in bone hole124beyond the distal end122of the tissue120, as illustrated inFIG.11. As the first end52of the suture strand50is pulled, the first adjustable loop56will shorten, thus drawing the first suture tail70aagainst the anchor90, and deforming the anchor90so that the anchor90will be retained in the bone110. The first adjustable loop56will also span and contact the distal end122of the tissue120in order to retain the distal end122to the bore110. The first end72aof the first suture tail70awill catch on an end of the anchor90and the first adjustable loop56will pull the second adjustable loop58, as well as the tissue120, towards the anchor90, thereby tensioning the tissue120in the anterior to posterior direction, for example.

With reference toFIG.12, another tissue fixation device according to the present teachings is illustrated at numeral210. The tissue fixation device210generally includes a soft or flexible anchor212and a self-locking construct214. The soft or flexible anchor212can be any suitable anchor, such as the anchor12described above, or any suitable alternate configurations thereof, such as the alternate configurations described above. The anchor212generally includes a first end220and a second end222, which is opposite to the first end220. The anchor212defines a first opening224at the first end220, and a second opening226at the second end222. An anchor internal passage228extends through the anchor212between the first opening224and the second opening226.

The self-locking construct214can be any suitable self-locking construct, such as a construct including a suture250. Alternately, the construct214can be any of the alternate constructs described above with respect to the construct14. The suture250generally includes a first end252and a second end254, which is opposite to the first end252. The construct214defines a first loop256and a second loop258, which are formed as described below.

A first body portion260of the suture250is generally between the first loop256and the second loop258, and defines a passageway262extending between a first end264and a second end266, through which the suture250extends to define the first loop256. The first loop256extends from the first body portion260. The suture250further includes a second body portion270proximate to the second end254. The second body portion270defines a passageway272extending between a first opening274and a second opening276through which the suture250extends to define the second loop258. The second loop258extends from the second body portion270. The anchor212is seated on the first loop256, such that portions of the suture250defining the first loop256extend through the anchor internal passage228.

The tissue fixation device210further includes a first tail280aand a second tail280b. The first tail280ais coupled to the first loop256, and the second tail280bis coupled to the second loop258. The first and second tails280aand280bcan be made of any suitable material, such as braided hollow-core suture. The first and second tails280aand280bcan also be made of the same material that the first and second suture tails70aand70bofFIG.1are made of.

The first tail280ais substantially similar to, or the same as, the second tail280b. Therefore, the description of the first tail280aalso applies to the second tail280b. Features in common between the first tail280aand the second tail280bare illustrated and described using like reference numbers, with the features of the first tail280aincluding the suffix “a” and the features of the second tail280bincluding the suffix “b.” To facilitate distinguishing between the first and second tails280aand280b, such as by a surgeon in an operating room, the first and second tails280aand280bcan include any suitable distinguishing features. For example, the first tail280acan have a different color, pattern, design, length or width as compared to the second tail280b.

The first tail280aincludes a first end282aand a second end284a, which is opposite to the first end282a. Proximate to the first end282ais a locking member/portion286a. Extending from the locking member/portion286ato the second end284ais a first tail portion288a. The first tail280adefines a passageway290aat the locking member portion286a. The passageway290aextends between a first opening292aand a second opening294aof the first tail280a. The first loop256extends through the passageway290a. The first tail280aand the second tail280bcan be used to adjust the sizes of the first and the second loops256and258respectively, as described herein with respect toFIGS.22A-22C.

The first loop256can be made smaller by pulling the first end252through the passageway262, thereby pulling a portion of the suture250proximate to the first end252through the passageway262. The second loop258can be made smaller by pulling the second end284bof the second tail280baway from the passageway272so as to slide the second body portion270towards the second tail280b. Although the second loop258is illustrated as an adjustable loop, the second loop258can be a rigid loop fixedly secure at the second body portion270, for example, so as to restrict the second loop258from opening or closing.

The tissue fixation device210can be implanted in bone110in any suitable manner, such as described above with respect to the tissue fixation device10inFIG.2. The tissue fixation device210can be used to secure tissue120to the bone110in any suitable manner, such as described above with respect to the tissue fixation device10. For example, the anchor212can be seated into the bone hole118and then the first and second tails280aand280bcan be passed through the tissue120. The first tail280acan be passed through the second loop258, so as to arrange the first loop256such that a portion thereof extends through the second loop258. The first loop256can be made smaller so as to press against and onto the tissue120by pulling the first end252, which reduces the length of the first loop256.

As the first end252is pulled, the locking member/portion286aengages the second loop258, so as to prevent the first tail280afrom passing back through the second loop258. Furthermore, tension between the portion of the suture250extending through the passageway262and an interior of the passageway262causes the passageway262to collapse on the suture250and prevent the first loop256from reopening. If the second loop258is provided as a flexible loop, the second loop258may be made smaller by pulling the second tail280b. Tension between the portion of the suture250extending through the passageway272and an interior of the passageway272cause the passageway272to collapse onto the suture250and prevent the second loop258from reopening.

AlthoughFIG.12illustrates the tissue fixation device210with the anchor212on the first loop256, the anchor212of the tissue fixation device210can be initially seated on the first tail280a, as illustrated inFIG.13, such that the first tail portion288aextends through the anchor internal passage228. With reference toFIGS.14-18, use of the tissue fixation device210ofFIG.13with the anchor212initially seated on the first tail280ato secure tissue120to the bone110will now be described. In applications where the anchor212is initially seated on the first loop256, as illustrated inFIG.12, the method ofFIGS.14-18may also be used to secure tissue120to bone110.

The anchor212is initially implanted in the bone hole118, and the first tail280ais passed through the tissue120. A cannula310is arranged such that it extends through a patient's outer skin layer to facilitate introduction of the tissue fixation device210to an implant site, and to facilitate manipulation of the tissue fixation device210outside of the patient's body. By arranging the anchor212on the first tail280aas opposed to on the first loop256as illustrated inFIG.12, the construct214can remain outside of the joint space during much of the procedure to facilitate management of the fixation device210, and particularly management of the construct214.

After the first tail280ais passed through the tissue120as illustrated inFIG.14, the second tail280bis passed through the cannula310, through the tissue120, and back through the cannula310, as illustrated inFIG.15. With reference toFIG.16, the first tail280ais then passed through the second loop258. Passing the first tail280athrough the second loop258draws the construct214through the cannula310and into engagement with the tissue120, as illustrated inFIG.17. More specifically, the first tail280ais pulled until it completely passes through the tissue120and pulls the first loop256through the anchor212and up from the anchor212through the tissue120. Pulling the first tail280aalso positions the second tail280bat the tissue120such that the locking member/portion286babuts the tissue. To close the first loop256and secure the tissue120against the bone110, the first end252of the suture250is pulled, as illustrated inFIG.17. Excess portions of the first and second tails280aand280bcan be removed after the first loop256has been completely zipped down, as illustrated inFIG.18for example. Thus, with the tissue fixation device210, only a single suture strand need be pulled to close and tighten the construct214against the tissue120.

A single tissue fixation device210can be used to secure the tissue120to the bone110, or multiple tissue fixation devices210can be used. For example, multiple tissue fixation devices210can be individually implanted and not connected to each other, similar to the arrangement illustrated inFIG.3with respect to the tissue fixation device10. Alternatively, multiple ones of the tissue fixation device210can be linked together, similar to the arrangement ofFIGS.3and8with respect to the tissue fixation device10. Thus, the first loop256of the tissue fixation device210can be coupled to the second loop258of a neighboring tissue fixation device210by inserting the first tail280athrough the second loop258of the neighboring tissue fixation device. Furthermore, the first or second tails280aor280bcan be coupled to an anchor, which then may be implanted in bone, similar to that which is illustrated inFIG.11with respect to the tissue fixation device10.

With additional reference toFIG.19, the tissue fixation device210can include a second tail in the form of a braided strip350. The braided strip350can be made of any suitable material, such as suture, or of any of the alternatives described above with respect to the suture strands50and250. The braided strip350generally includes a flat braided portion352and a round braided portion354, as viewed in cross-section, extending from the flat braided portion352.

The flat braided portion352defines a first opening356and a second opening358. As illustrated inFIG.19, the second loop258passes through the first and second openings356and358in order to secure the braided strip to the second loop258. However, the second loop258is optional and thus need not be included. When the tissue fixation device210does not include the second loop258, the braided strip350can be coupled to the suture250without a loop, such as with a knot or any other suitable coupling configuration. The braided strip350may also be unitary with the rest of the suture250.

Instead of passing the first tail280athrough the second loop258, the first tail can be passed through the flat braided portion352of the braided strip350. As a result, when the first loop256is made smaller, as was described above in connection withFIG.17, the braided strip350will extend across the tissue120in order to dissipate load applied to the tissue120by the tissue fixation device210. The round braided portion354expands the distance that the braided strip350will extend across the tissue120, thereby further dissipating load.

FIG.19illustrates the braided strip350(without the round braided portion354) as included with the tissue fixation device210prior to being introduced to an implant site. However, the braided strip350may be added to the fixation device210after the first loop256has been passed through the tissue, as illustrated atFIG.20. For example, the braided strip350may be arranged at the second end284aof the first tail280aand at the second end284bof the second tail280b. The first and second ends282aand284bmay be passed through the braided strip350, and the braided strip350may be slid down and across each of the first and second tails280aand280busing a pusher device380until the braided strip350passes over the first ends282aand282bof the first and second tails280aand280brespectively. After the first end252of the suture250is pulled to close the first loop256, excess portions of the first and second tails280aand280bmay be removed, as illustrated inFIG.21.

With reference toFIGS.22A-22C, when the tissue fixation device210is provided with the second loop258as an adjustable loop, the second loop258can be moved from an intermediate position illustrated inFIG.22Ato a closed position illustrated inFIG.22Bby pulling a portion of the suture250extending beyond the second body portion270in the direction of the first end252(direction A), and pulling the second end284bof the second tail280bin generally the opposite direction (direction B). To reopen the second loop258, the second end254of the suture250is pulled in direction C and the second end284bof the second tail280bis pulled in direction D, as illustrated inFIG.22C. Being able to selectively open and close the second loop258is advantageous for a number of reasons. For example, if the second loop258is accidentally closed prematurely, the second loop258can easily be reopened, such as to permit passage of the first tail280atherethrough.

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.