Abstract:
A minimally invasive suture insertion device utilizing small gage needles is provided for threading one or more sutures through subcutaneous tissue, both locally and from remote access points, to support, attach, sever, ligate or constrict tissue, vessels, ligaments, nerves or other anatomical features, or for pulling another device into position defined by a suture pathway. A manually operated suture transfer device and method are provided for use in various surgical applications. The suture transfer device operates as an instrument for inserting sutures into and through desired pathways. Tethered cannulas are coupled to the positioned sutures and dock, transversely, with a captured component having a capacity for engaging a single suture or multiple sutures, together or in turn within subcutaneous tissue from local or remote access points.

Description:
RELATED CASE 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/852,050, filed Mar. 15, 2013, the subject matter of which is incorporated by reference as if fully set forth herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to an apparatus capable of enabling a practitioner to thread a suture in subcutaneous tissue from a remote access point, to surgical methods facilitated by such an apparatus, and to associated tools useful with the apparatus for performing such surgical methods. 
         [0003]    Various surgical methods require the placement of a suture deep inside subcutaneous tissue for the purpose of supporting, severing, ligating, or constricting tissue, vessels, ligaments, nerves or other anatomy or for pulling another device into position defined by the suture pathway. Typically, this necessitates making an incision through the skin and subcutaneous tissue in order to gain sufficient access for deploying the suture directly to the desired location, for example, in an open surgical procedure or for feeding a suture passing instrument with an endoscopic or laparoscopic instrument to a distal location from the initial point of access. 
         [0004]    An example of one such procedure, in the field of plastic surgery, is the mid-face lift. As part of this procedure, an incision is made in an inconspicuous location to conceal the incision and to make scarring less obvious. The facial tissue is then separated to achieve sufficient access and mobility of the tissue to permit one or more sutures to be deployed to reattach and/or reposition the tissue into a more aesthetically desirable result. In addition, it is often desirable to anchor ends of the sutures to a rigid structure, for purposes of support. In practice, however, the selection of an anchoring structure which is suitable for fixation, which is accessible, and which can provide an inconspicuous incision, often complicates the procedure and results in a significant distance between the supported tissue and the fixation structure. The can result in a procedure which requires extensive surgery, which can be expensive, which can create significant trauma to the tissue, and which can take a significant amount of time to heal (e.g., a matter of weeks), and may also create sub-optimal aesthetic results. 
         [0005]    Various procedures have been attempted to reduce the resulting trauma to a patient, the corresponding expense of the procedure, and the time required for recovery. For example, one attempted procedure has been to use needles to implant a device having barbed profiles capable of engaging subcutaneous tissue at a location remote from the point of access. In practice, however, such barbs have been found to be prone to release after a relatively short period of time, often on the order of a few months. Release of the barbs then allows the engaged tissue to sag. 
         [0006]    Other attempted procedures have made use of endoscopes to reduce the size of the accessing incision. However, endoscope-guided suturing devices are bulky mechanisms, and tend to require considerable separation of the tissue layers and the severing of connective fibers in order to pass the instrument from the incision at the anchor location to the intended base of the suture supporting loop, and to surgically release the naturally occurring connective fibers so that the lift will be effective. Moreover, in the case of an endoscopic-guided mid-face lift, significant care and skill are required to avoid rupturing critical branches of the facial nerve as the device traverses a path from the temporal fascia to the intended location. Furthermore, endoscopic suturing devices are limited in the amount of tissue that can be engaged distally to distribute the lifting force, which can make the sutures prone to pull through the tissue (so-called “cheese-wire effect”) over time. Additionally, the endoscopic mid-face lift begins in the temporal fascia in the hairline in order to hide the insertion incision scar and to provide a suitable structure to anchor the sutures. However, this alters the naturally occurring anchor location of the mid-face tissue to a location which is substantially superior and which can result in a lift vector which is long and constrained by other anatomy, which can affect the aesthetics of the lift. 
         [0007]    It has therefore remained desirable to provide a minimally invasive technique for redirecting a suture along a desired pathway or to transfer a suture from one internal pathway to another through the use of external manipulation and tactile feel, as well as to achieve an optimum suture deployment vector for a desired procedure, while providing a practitioner with considerable flexibility in the choice of vector and suture configurations and the ability to capture multiple sutures. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with the present invention, an apparatus and associated tools are provided for enabling a practitioner to thread a suture in subcutaneous tissue from a remote access point, to facilitate any of a variety of surgical methods. In addition to enabling advantageous placement of the suture, the device utilizes small gage needles to penetrate the skin. As a result, there is no incision, or a concern for scarring, which enables the location of an anchoring point to be selected to optimize the procedure to be performed. 
         [0009]    For convenience of description, the discussion which follows will primarily refer to use of the present invention to perform a mid-face lift. Nevertheless, it is to be understood that improvements in accordance with the present invention can be used to perform other procedures, including other mid-face lift procedures, and other lift procedures, as well as other surgical procedures which can benefit from the noninvasive percutaneous deployment and manipulation of a suture in a pathway. 
         [0010]    As an example, and for the illustrative case of a mid-face lift, this enables the suture to be placed through the skin and into the periosteum of the zygomatic arch, which then serves as the anchoring structure for the mid-face lift. In addition to providing a strong anchoring location for the lift, the zygomatic arch is a naturally occurring anatomical fixation point for the tissue that comprises the mid-face. 
         [0011]    Additionally, the present invention enables an improved aesthetic result to be achieved by allowing the development of a more aesthetic lift vector and a shorter lift length. 
         [0012]    This is to be distinguished from other procedures, such as the modified “S-Lift”, which provides access to the mid-face from an incision around the ear, and the previously described endoscopic lift, which can both disrupt and sever the connective tissue which connects the mid-face to the zygomatic arch, and which can result in a more dramatic aesthetic change with significant repositioning of tissue which may be considered undesirable and less natural. 
         [0013]    In addition to aesthetic advantages, and by providing a naturally occurring aesthetic vector which is shorter, the present invention can achieve a vector which, for the example of a mid-face lift, can advantageously be contained within a safe region known as the golden triangle, and which avoids having to insert surgical instruments past sensitive anatomy such as the temporal branch of the facial nerve which, if severed, can result in paralysis of the face. 
         [0014]    Additionally, the present invention enables the suture to be threaded inside the tissue without disrupting the surrounding tissue, in an advantageous configuration that is controlled by the surgeon, and which minimizes trauma and enables the surgeon to avoid the need to sever naturally occurring ligature connecting the mid-face to the zygomatic arch, 
         [0015]    Further, and for the illustrative example of a mid-face lift, the present invention enables the surgeon to deploy a suture in a triangular loop support structure with the apex of the triangle at the anchor location and a relatively wide base, typically on the order of 1 cm, in the soft tissue to better distribute the lifting force. 
         [0016]    The advantages obtained using the improvements of the present invention for the noninvasive percutaneous deployment of a suture pathway in the illustrative example of the mid-face lift are also applicable to various other procedures. 
         [0017]    As another illustrative example, improvements in accordance with the present invention can be used to create a subcutaneous suture loop around a tendon or a ligament without necessitating an incision. In the case of carpal tunnel surgery, a tendon is typically severed in an open procedure dissecting down to the tendon and the tendon is then severed with a scalpel. Instead, a suture loop, for example, in a U-shaped configuration) can be deployed around the tendon using the improvements of the present invention. Guidance of the structures around critical anatomy, such as nerves, can be achieved with ultrasonic guidance. Then, the suture loop can be manipulated back and forth to cut through the tissue. A separate needle can be deployed, if desired, to limit passage of the suture loop through engaged tissue in cases where a complete severing of the tissue is not to take place. As a further alternative, the procedure can be performed with saline, for example, for hydro-dissection, or with the addition of an anesthetic. Similar techniques can be used for the suturing used to repair an Achilles Tendon, or for repairing Varicose veins, or to close off an organ or vessel by tying it shut. 
         [0018]    Improved instruments and methods for deploying and manipulating sutures in subcutaneous tissue are described in International Application No. PCT/US2008/009012, filed Jul. 25, 2008, which describes an external guide for aligning a suture with subcutaneous eyelets, and an expandable aperture for engaging a strand which is hidden from view; and in U.S. patent application Ser. No. 12/384,326, filed Apr. 2, 2009 (also International Application No. PCT/US2010/000891, filed Mar. 25, 2010), which describe an external guide for aligning a suture with internal eyelets which can be tethered, as well as removable, the subject matter of each of which is incorporated by reference as if fully set forth herein. 
         [0019]    In practice, however, the geometry of these guide structures must be taken into account by a practitioner when deploying such devices. This has the potential for reducing the practitioner&#39;s flexibility, which can in turn require sub-optimal positioning of the suture loop in order to accommodate variations in a patient&#39;s anatomy, which can limit the locations in the body where such devices can be used. There is also the potential for bending forces to affect guided needle systems, which can cause deflection of the needle to increase exponentially with the length of the needle. This can in turn limit the ability of the guiding needle to couple with its target as the distances increase, unless the needle profiles are increased in size to increase stiffness and/or the needle lengths are kept short and/or the size of the targeted elements is increased. However, this can limit the minimum bore diameter of the needles. 
         [0020]    In addition, such structures also involve the coupling of elements, such as eyelets, to the guides, which can result in additional components and procedural steps for the practitioner. In accordance with the present invention, subcutaneous coupling with a distally deployed cannula, or other cooperating element, permits even the more complex suture pathway to be configured in the subcutaneous tissue into a desired a loop configuration or some other prescribed pathway without requiring an external alignment structure. Moreover, bending forces on subcutaneous tools are better accommodated by allowing for re-directed adjustment of the components to achieve the desired coupling, which can be confirmed by tactile feel, electronic sensing, as well as ultrasonic or other guidance systems toward subcutaneous needles for subcutaneous mating with target elements. This significantly increases the percutaneous flexibility of the practitioner to manipulate suture pathway into optimally desired configurations, making the use of improvements in accordance with the present invention appropriate for a wider variety of procedures and anatomical targets. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a plan view of the preferred embodiment of the engagement tool. 
           [0022]      FIG. 2  is an enlarged view of region  2  of  FIG. 1  showing the engagement mechanism. 
           [0023]      FIGS. 3 and 4  are cross-sections of the penetrating member shown in  FIG. 1 . 
           [0024]      FIG. 5  is an isometric view of region  5  in  FIG. 1  in the region of the engagement feature. 
           [0025]      FIG. 6  is a plan view of the engagement tool with actuator depressed and the capture mechanism retracted. 
           [0026]      FIG. 7  is an enlarged plan view of the distal end of the engagement mechanism in region  7  of  FIG. 6 . 
           [0027]      FIG. 8  is an expanded isometric view of region  8  in  FIG. 7  showing the engagement feature. 
           [0028]      FIG. 9  is a plan view of a tethered cannula tool. 
           [0029]      FIG. 10  is an isometric view of the engagement tool in transverse alignment with a tethered cannula. 
           [0030]      FIG. 11  is an enlarged isometric view of region  11  of  FIG. 10  showing transverse alignment of engagement tool with tethered cannula at the engagement feature. 
           [0031]      FIG. 12  is a plan view of enlarged region  11  of  FIG. 10  showing transverse alignment of engagement tool with tethered cannula at the engagement feature. 
           [0032]      FIG. 13  is an isometric view of the narrow cannula of a tethered cannula in the vertical slot of the engagement feature of the engagement tool with the actuator depressed. 
           [0033]      FIG. 14  is an enlarged isometric view of region  14  of  FIG. 13  showing the narrow cannula of the tethered cannula in the vertical slot of the engagement feature. 
           [0034]      FIG. 15  is a plan view of  FIG. 14 . 
           [0035]      FIG. 16  is an isometric view of the engagement tool with the actuator released and the narrow cannula captured in the engagement feature. 
           [0036]      FIG. 17  is an isometric view of the enlarged region  17  of  FIG. 16  showing the capture mechanism retaining the narrow cannula in the engagement feature. 
           [0037]      FIG. 18  is a plan view of  FIG. 17 . 
           [0038]      FIG. 19  is an isometric view of a strand captured in the engagement feature. 
           [0039]      FIG. 20  is a plan view two strands captured in the engagement feature. 
           [0040]      FIG. 21  is a plan view of an alternative embodiment engagement mechanism with a hook and a “V” shaped engagement feature. 
           [0041]      FIG. 22  is an isometric view of region  22  of  FIG. 21 . 
           [0042]      FIG. 23  is a plan view of the alternative embodiment shown in  FIG. 21  with the hook in a retracted position for capturing a tethered cannula or strand. 
           [0043]      FIG. 24  is an isometric view of region  24  of  FIG. 23 . 
           [0044]      FIG. 25  is a plan view of the penetrating member of an alternative embodiment of an engagement mechanism which couples with a rotating capture mechanism. 
           [0045]      FIG. 26  is an isometric view of the penetrating member of  FIG. 25 . 
           [0046]      FIGS. 27 ,  28 ,  29  and  30  are plan views of a rotating capture mechanism which couples with the penetrating member shown in  FIG. 25 , with each view progressively rotated by 90 degrees. 
           [0047]      FIG. 31  is an isometric view of the rotating capture mechanism shown in  FIGS. 27 ,  28 ,  29  and  30 . 
           [0048]      FIGS. 32 ,  33  and  34  are progressive plan views of the engagement mechanism with the rotating capture mechanism progressively rotated to show the stages of capture in the engagement features. 
           [0049]      FIG. 35  is a plan view of an alternative embodiment of the engagement mechanism including a capture mechanism with a flexible latch and a guard in a forward position restricting the latch from flexing. 
           [0050]      FIG. 36  is an isometric view of region  36  of  FIG. 35 . 
           [0051]      FIG. 37  is a plan view the engagement mechanism shown in  FIG. 35  with the guard retracted to allow the latch to flex. 
           [0052]      FIG. 38  is an isometric view of region  38  of  FIG. 37 . 
           [0053]      FIG. 39  is a plan view of the engagement mechanism shown in  FIG. 37  with the latch flexed inwardly by an external force. 
           [0054]      FIG. 40  is an isometric view of region  40  of  FIG. 39 . 
           [0055]      FIG. 41  is a plan view of another alternative embodiment of an engagement mechanism with a latch. 
           [0056]      FIG. 42  is an isometric view of region  42  of  FIG. 41 . 
           [0057]      FIG. 43  is a plan view of the engagement mechanism shown in  FIG. 41  with the latch flexed inwardly by an external force. 
           [0058]      FIG. 44  is an isometric view of region  44  of  FIG. 43 . 
           [0059]      FIG. 45  is a plan view of an alternative embodiment engagement mechanism where the capture mechanism translates across a guard/support and provides capture for multiple engagement features. 
           [0060]      FIG. 46  is an isometric view of region  46  of  FIG. 45 . 
           [0061]      FIG. 47  is a plan view of the progressive advancement of the capture mechanism for the engagement mechanism shown in  FIG. 45  showing capture in the proximal engagement feature. 
           [0062]      FIG. 48  is an isometric view of region  48  of  FIG. 47 . 
           [0063]      FIG. 49  is a plan view of the continued progressive advancement of the capture mechanism for the engagement mechanism of  FIG. 45  showing capture in the distal engagement feature. 
           [0064]      FIG. 50  is an isometric view of region  50  of  FIG. 49 . 
           [0065]      FIG. 51  is a plan view of an alternative embodiment of an engagement mechanism which incorporates a capture mechanism with a flexible latch that flexes outward when a force not shown is applied to the latch along the horizontal slot of the engagement feature. 
           [0066]      FIG. 52  is an isometric view of region  52  of  FIG. 52 . 
           [0067]      FIG. 53  is a plan view of the engagement mechanism of  FIG. 51  where the capture mechanism is flexed outwardly by a force which is applied through the horizontal slot of the engagement feature. 
           [0068]      FIG. 54  is an isometric view of region  54  of  FIG. 53 . 
           [0069]      FIG. 55  is a plan view of an alternative embodiment of an engagement mechanism which includes a capture mechanism which is capable of flexing over and capturing a tethered cannula in transverse alignment at the engagement feature. 
           [0070]      FIG. 56  is an isometric view of region  56  of  FIG. 55 . 
           [0071]      FIG. 57  is a plan view of the engagement mechanism of  FIG. 55  where the capture mechanism is shown in an advanced position where it has snapped over and captured a tethered cannula in the engagement feature. 
           [0072]      FIG. 58  is an isometric view of region  58  of  FIG. 57 . 
           [0073]      FIG. 59  is a plan view of an alternative embodiment of an engagement mechanism where the capture mechanism is designed to protrude from the distal tip of the penetrating member. 
           [0074]      FIG. 60  is a plan view of the engagement mechanism of  FIG. 59  with the capture mechanism extended beyond the distal tip of the penetrating member. 
           [0075]      FIG. 61  is an isometric view of region  61  of  FIG. 60 . 
           [0076]      FIG. 62  is a plan view of the engagement mechanism of  FIG. 59  partially retracted into the tip of the penetrating member. 
           [0077]      FIG. 63  is an isometric view of region  63  of  FIG. 62 . 
           [0078]      FIG. 64  is a plan view of an alternative embodiment of an engagement mechanism similar to the embodiment of  FIG. 59  but where the penetrating member shows a beveled tip rotated by 180 degrees. 
           [0079]      FIG. 65  is a plan view of the engagement mechanism of  FIG. 64  shown with the capture mechanism extended. 
           [0080]      FIG. 66  is an isometric view of region  66  of  FIG. 65 . 
           [0081]      FIG. 67  is a plan view of the engagement mechanism of  FIG. 65  with the capture mechanism partially retracted. 
           [0082]      FIG. 68  is an isometric view of region  68  of  FIG. 67 . 
           [0083]      FIG. 69  is a plan view of an alternative engagement mechanism where the penetrating mechanism includes a helical section. 
           [0084]      FIG. 70  is a plan view of the engagement mechanism of  FIG. 69  with the capture mechanism shown as a rod inserted through the helical section. 
           [0085]      FIGS. 71 ,  72  and  73  are progressive plan views of an alternative embodiment similar in function to the embodiment shown in  FIG. 35  of an engagement mechanism including a capture mechanism with a flexible latch and a movable guard/support. 
           [0086]      FIGS. 74 ,  75 ,  76  and  77  are progressive plan views of an alternative embodiment of an engagement mechanism showing a capture mechanism with engagement features which can protrude from the end of the penetrating member in various positions of extension and retraction for engagement and capture. 
           [0087]      FIGS. 78 ,  79 ,  80  and  81  are progressive plan views of an alternative embodiment of an engagement mechanism showing a capture mechanism with engagement features which can protrude from the end of the penetrating member in various positions of extension and retraction for engagement and capture, with the bevel on the end of the penetrating member rotated 180 degrees from  FIGS. 74 ,  75 ,  76  and  77 . 
           [0088]      FIGS. 82 ,  83 ,  84  and  85  are progressive plan views of an alternative embodiment of an engagement mechanism which show a penetrating member with a modified tip. 
           [0089]      FIG. 86  is a plan view of an alternative embodiment of an engagement mechanism similar to the embodiment shown in  FIG. 35  but without the guard/support. 
           [0090]      FIG. 87  is a plan view of the engagement mechanism of  FIG. 86  with the capture mechanism bent inwardly by a force. 
           [0091]      FIG. 88  is a plan view of an alternative embodiment of an engagement mechanism with a capture mechanism that is inflatable. 
           [0092]      FIG. 89  is a plan view of the engagement mechanism of  FIG. 88  where the capture mechanism is inflated. 
           [0093]      FIG. 90  is a plan view of an alternative embodiment of an engagement mechanism where the guard directly blocks off the engagement region in the closed state and the guard and capture mechanism are both movable. 
           [0094]      FIG. 91  is a plan view of the engagement mechanism of  FIG. 90  with the guard and capture mechanism retracted and the capture mechanism flexed inwardly by a force. 
           [0095]      FIG. 92  is a plan view of an alternative embodiment of an engagement mechanism where the capture mechanism includes a coil which is housed within the penetrating member. 
           [0096]      FIG. 93  is a plan view of the engagement mechanism of  FIG. 92  where the coiled section of the capture mechanism is compressed in a position to capture tethered cannulas or strands between the coils. 
           [0097]      FIG. 94  is a plan view of an alternative embodiment of an engagement mechanism where the capture mechanism includes a coil which is wrapped around the outside of the penetrating member. 
           [0098]      FIG. 95  is a plan view of the engagement mechanism of  FIG. 94  where the coiled section of the capture mechanism is compressed in a position to capture tethered cannulas or strands between the coils. 
           [0099]      FIG. 96  is a plan view of an alternative embodiment of an engagement mechanism in which the capture mechanism includes a coil which can protrude from the end of the penetrating member. 
           [0100]      FIG. 97  is a plan view of the engagement mechanism of  FIG. 96  showing the coils of the capture mechanism partially retracted into the penetrating member. 
           [0101]      FIG. 98  is a plan view of an alternative embodiment of the engagement mechanism with a capture mechanism which includes a brush which when rotated will engage a strand by grabbing the suture and winding it around the brush. 
           [0102]      FIGS. 99 ,  100 ,  101  and  102  are progressive plan views of an alternative embodiment of the engagement mechanism which include telescoping capture mechanisms. 
           [0103]      FIGS. 103 ,  104  and  105  are progressive plan views of an alternative embodiment of the engagement mechanism which show a capture mechanism with a front and rear hook section and the progressive stages of capture. 
           [0104]      FIGS. 106 and 107  are plan views of an alternative embodiment of an engagement mechanism with a capture mechanism which includes a magnet and interaction with a strand which includes magnetic particles. 
           [0105]      FIG. 108  is a plan view of an alternative embodiment of the engagement mechanism which includes a capture mechanism with a flexible member. 
           [0106]      FIGS. 109 and 110  are progressive plan views of an alternative embodiment of the engagement mechanism which includes a capture mechanism which can open and close around a tethered cannula or strand which exerts an inwardly directed force on the capture mechanism. 
           [0107]      FIGS. 111 and 112  are progressive plan views of an alternative embodiment of the engagement mechanism which includes a capture mechanism with jaws that can be opened and closed around a tethered cannula or strand. 
           [0108]      FIGS. 113 and 114  are progressive plan views of an alternative embodiment of the engagement mechanism which includes a flexible capture mechanism with barbs which when extended can pass over a tethered cannula and when retracted engage and capture a strand or a tethered cannula. 
           [0109]      FIGS. 115 and 116  are progressive plan views of an alternative embodiment of the engagement mechanism with a capture mechanism with a spring loaded ball. 
           [0110]      FIGS. 117 and 118  are progressive plan views of an alternative embodiment of the engagement mechanism with a capture mechanism including a sheath which slides to open or close off the engagement feature. 
           [0111]      FIGS. 119 and 120  are plan views of an alternative embodiment of the engagement tool which include a fluid pathway for dispensing fluid through the penetrating member. 
           [0112]      FIG. 121  is a plan view of an embodiment of a routing tool used to place tethered cannulas or strands in position for engagement with the engagement tool. 
           [0113]      FIG. 122  is a plan view of region  122  of  FIG. 121  showing the front section of the penetrating member of the routing tool. 
           [0114]      FIG. 123  is a plan view of the routing tool of  FIG. 121  where the blunting mechanism of the routing tool is engaged forward and latched into position. 
           [0115]      FIG. 124  is a plan view of region  124  of  FIG. 123  which shows the blunting mechanism extended passed the point of the penetrating member. 
           [0116]      FIG. 125  is an isometric view of the routing tool coupled to a tethered cannula. 
           [0117]      FIG. 126  is an expanded isometric view of region  126  of  FIG. 125  showing the coupling of the strand of the tethered cannula to the routing tool. 
           [0118]      FIGS. 127 ,  128  and  129  are progressive plan views of an alternative embodiment of the front end of the routing tool which includes a strand which enables the routing tool to couple directly with an engagement tool without coupling with an external strand. 
           [0119]      FIG. 130  is a plan view of an alternative embodiment of a routing tool which includes a fluid passageway for dispensing fluid through the penetrating member. 
           [0120]      FIG. 131  is an expanded plan view of region  131  of  FIG. 120  showing the fluid pathway through the front end of the routing tool. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0121]      FIG. 1  shows an embodiment of an apparatus produced in accordance with the present invention which is presently considered as being preferred. The engagement tool  1  includes a body  2  with a penetrating member  3  which is affixed to the body. In the preferred embodiment, the penetrating member  3  is made from a cannula which allows a capture mechanism  4  to translate within the penetrating member  3 . In other embodiments, the penetrating member  3  can be of other constructions, including solid materials, and the capture mechanism can be affixed to the penetrating member or coupled to the outside of the penetrating member. The penetrating member  3  is shown with a pointed tip at the distal end of the penetrating member  3 , which is preferred to facilitate entry into tissue such as skin. The tip of the penetrating member can also be of other configurations, including blunt or rounded shapes, if appropriate for an application where the device can readily pass through tissue without having a sharp point, such as when there is a prior incision or puncture. An introducer needle can be used to facilitate the insertion of a penetrating member having a blunt or rounded tip, if desired. 
         [0122]    In the preferred embodiment of  FIG. 1 , an actuator  5  interacts with a carriage  6 , which is preferably coupled to the proximal end of the capture mechanism  4 . In this preferred embodiment, when the actuator is depressed, the actuator  5  rotates about a pivot and the gears of the actuator interact with the linear gears of the carriage, causing the capture mechanism  4  to reciprocate within the penetrating member  3 .  FIG. 6  shows the engagement tool  1  with the actuator  5  depressed and rotated forward, placing the carriage  6  and the attached capture mechanism  4  in a retracted position and compressing a return spring  7  for returning the capture mechanism to its original state when the actuator mechanism is released. Any of a variety of actuator mechanisms can be used as alternatives. For example, the penetrating member can translate and the capture mechanism can be fixed, or the actuator can be directly coupled to the penetrating member or the capture mechanism, where no carriage is used, and where there is no spring return. It is also possible to manually couple a capture mechanism to the penetrating member without an actuator. 
         [0123]    Referring again to the preferred embodiment in  FIG. 1 , the engagement tool  1  also includes an indicator  8 . In applications where the penetrating member  3  is inserted into tissue, the penetrating member is typically hidden from view. The indicator  8 , as shown, remains above the tissue and provides a visual indication of the location of features of the penetrating member. For example, an engagement locator  9  can be used to locate suture engaging features of the penetrating member, and a tip locator  10  can be used to locate the tip of the penetrating member. The indicator  8  is preferably made from a flexible material, for example, nitinol wire, which is sufficiently stiff to provide the desired visual indication, but with the added feature that the indicator can be bent out of the way of occluded tissue which may occur as the user introduces the device into the skin or manipulates the device toward the target location. In the preferred embodiment, the locators  9  and  10  are applied adhesive materials. Other flexible and non-flexible materials can also be used, as well as well as other forms of visual locators, such as beads or sleeves. A plurality of engagement locators  9  can be used to identify multiple engagement locations, if desired. 
         [0124]      FIG. 2  is an enlarged view of the engagement region  2  identified in  FIG. 1 , showing the distal end  11  of the penetrating member  3 . In the preferred embodiment, the penetrating member  3  includes an engagement feature  12  which is shown as an “L” shaped relief in the penetrating member. While  FIG. 2  shows only one engagement feature  12 , it is possible to have more than one engagement feature, if desired.  FIG. 5  is an isometric view of the region  5  shown in  FIG. 1 . 
         [0125]    In the preferred embodiment the capture mechanism  4 , which is shown in its forward-most position, includes an angled front tip. In this location, the engagement feature  12  is closed, preventing it from receiving an object, such as a cannula or suture. While it is also possible to leave the engagement feature partially open so that it can receive a small diameter object, such as a suture or cannula, unless the engagement feature is smoothly contoured it will act as a catch point when penetrating or retracting through tissue, particularly when used to penetrate skin. By blocking the opening with the capture mechanism, tissue is prevented from getting caught on or in the engagement feature. A further advantage of the illustrated embodiment is that while the capture mechanism  4  is in the state shown in  FIG. 2 , a transition remains along the penetrating member at the engagement feature which provides the user with a tactile indication that an object, such as a cannula or suture, which is held in a generally transverse orientation to the penetrating member in  FIG. 2 , traverses across the top of the penetrating member and comes in contact with the engagement feature  12 , as will later be shown  FIG. 15 . To be noted is that the term “transverse” is not intended to mean that the described features must meet at a right angle to each other, and that other angles can also be established for this. 
         [0126]      FIG. 7  shows the distal end of the engagement mechanism  11  with the capture mechanism  4  in a retracted position.  FIG. 8  is an enlarged isometric view of the distal end of the engagement mechanism  11  shown in Figure V. In this retracted state, the engagement feature is open to receive a desired object. 
         [0127]    The penetrating member  3  is preferably made from a cannula with a pointed tip. Referring to  FIG. 3 , the cannula is preferably flattened into an oval geometry in the region  13 , The main advantage of an oval geometry is structural strength, so that for a given depth of relief required to capture a desired object, there will still be sufficient strength in the penetrating member. While it is also possible to use a larger cannula for the penetrating member, to retain the structural integrity, it is typically desirable to minimize the size of the penetrating member to reduce unnecessary trauma to the tissue.  FIGS. 3 and 4  show preferred cross sections for the bracketed regions  13  and  15 . Bracketed region  14  is a transition region from the oval region  13  to the circular region  15 . 
         [0128]      FIG. 9  shows a preferred embodiment of a tethered cannula tool  16 . The tethered cannula tool  16  includes an alternative embodiment body  17  which holds an outer cannula  18  and narrow cannula  19  sized to interact with the engagement feature  12  of the engagement tool  1 . The cannulas  18  and  19  are further coupled with a strand  20 , which is preferably a suture but which can also be a flexible wire. The cannula  19  is preferably slidingly received within the cannula  18 , and the strand  20  is preferably slidingly received within the cannula  19 . 
         [0129]      FIG. 9  also shows an indicator  21  having cannula locators  22  and  23  which serve to identify the region where the narrow cannula  19  is exposed. The indicator  21  is preferably made with a flexible material, such as nitinol wire, for the same reasons as were previously discussed for the indicator  8  of the engagement tool  1  described in  FIG. 1 , and the locators  22  and  23  are preferably made with drops of adhesive, as previously described. Again, the indicator  21  may be made of a flexible or stiff material, and various markings or identifiers can be used to identify regions of the cannulas  18  and  19 . 
         [0130]    If the strand  20  is held in tension, the engagement tool  1  can interact with the strand without needing any of the other elements shown in  FIG. 9 . As an alternative, a single cannula (either  18  or  19 ) can be used with the strand  20  to interact with the engagement tool  1 . However, in practice, a tethered cannula which includes each of the elements  18 ,  19  and  20  is particularly advantageous when used in combination with the preferred embodiment of the engagement tool in  FIG. 1  as will be described below. 
         [0131]      FIG. 10  shows a tethered cannula associated with the tool  16 , including the outer cannula  18 , narrow cannula  19  and tether  20 , in transverse alignment with the engagement tool  1 .  FIGS. 11 and 12  are enlarged views of the region  11  of  FIG. 10 . 
         [0132]      FIGS. 10 to 12  show the outer cannula  18  positioned at the opening of the engagement feature  12  of the penetrating member  3 . The diameter of, and material forming the outer cannula are selected to give the tethered cannula sufficient strength, stiffness and geometry to facilitate engagement with the engagement tool. 
         [0133]    In use, it is advantageous to be able to manipulate the protruding member  3  of the engagement tool and the tethered cannula of the tool  16  into alignment. For the case where the tethered cannula is deployed first, the engagement tool is inserted into the tissue toward the tethered cannula. As the tip of the penetrating member of the engagement tool approaches the tethered cannula, the tissue can be manipulated by adjusting the attitude of the tethered cannula and the penetrating member until the tip of the penetrating member contacts the tethered cannula. The force of this manipulation exerts a bending force on the tethered cannula and, if the cannula is too weak, it becomes difficult to position the tissue so that the tethered cannula can contact the tip of the penetrating member and then progress along the upper surface of the protruding member, in the orientation shown, until coming into contact with the engagement region  12 . As an alternative, it is also possible for the end of the outer cannula  18  opposite the tether to be inserted into the tissue toward a previously deployed penetrating member of the engagement tool, if preferred for a given procedure. To facilitate this, the tip of the outer cannula  18  opposite the tether can be pointed. 
         [0134]    In the preferred embodiment, the geometry of the engagement region  12  provides the user with tactile feedback that the tethered cannula is positioned for engagement. The indicator  8  and engagement locator  9  of the engagement tool also provide the user with a visual indication as to where the engagement will occur, as would the indicator  21  of the tethered cannula tool  16  shown in  FIG. 9 , if used. 
         [0135]    While it is advantageous to have tactile feel and visual indicators, it is also possible to have other forms of indicators or alignment such as electrical signals that sense the contact of the different segments of the tethered cannula with other segments of the penetrating member of the engagement tool. Thin insulators, such as polymide tubing, can be used to isolate different elements of the tethered cannula and the penetrating member of the engagement tool so that when, for example, the outer cannula  18  contacts the penetrating member  3 , a signal is produced, and when the outer cannula  18  is in contact with the penetrating member  3  at the engagement feature, another signal is produced. Further signals can similarly be developed when the narrow cannula is in contact with the penetrating member or with the capture mechanism. Ultrasound or other sensing devices can also be used to detect features of the penetrating member  3 , if desired for a particular application. 
         [0136]    Referring to  FIG. 12 , the width of the upper opening of the engagement feature  12  is sufficiently large for the narrow cannula  19  to enter the engagement feature when the capture mechanism  4  is retracted. While the width of the opening could also be designed to accommodate the outer cannula  18 , it is advantageous to minimize the width of the opening to maintain as much structural integrity of the penetrating member as possible, so that it can be kept small in size. 
         [0137]    Referring next to  FIG. 13  and the enlarged view of zone  14  shown in  FIGS. 14 and 15 , the engagement tool is shown with the actuator  5  depressed and the capture mechanism  4  retracted. In a preferred sequence, the outer cannula  18  is held in contact with the penetrating member  3  at the engagement feature  12 . When the capture mechanism  4  is retracted, the tethered cannula  18  is withdrawn in the orientation shown until the narrow cannula  19  can enter the vertical slot in the engagement feature  12 . Again, while a vertical slot could be made to have a sufficient size to accommodate the outer cannula  18 , sizing the slot to only accommodate a narrow cannula  19  allows the strength and the size of the penetrating member to be improved, as previously discussed. 
         [0138]    At this point the actuator  5  is released, as shown in  FIG. 16 , and the capture mechanism advances to capture the narrow cannula  19  as shown in the enlarged views of the region  17  shown in  FIGS. 17 and 18 . The angled tip of the capture mechanism  4  then captures the narrow cannula  19  in the engagement feature  12  so it cannot be vertically removed from the engagement feature. In the preferred embodiment, the horizontal slot of the “L” shaped engagement feature is too small to receive the narrow cannula  19 . However, as the narrow cannula  19  is axially withdrawn, the strand  20  can enter the engagement feature and is driven by the capture mechanism along the small horizontal slot of the “L”, into the forward position shown  FIG. 19 . The stroke of the capture mechanism  4  is preferably limited so that a gap is left at the distal end of the horizontal slot of the “L” shaped engagement feature to allow several sutures to freely slide through this region without being impinged upon by the capture mechanism.  FIG. 20  shows a plan view showing two strands  20  at the distal end of the horizontal slot of the engagement feature, with the capture mechanism  4  in its extended position. It is also possible to have the capture mechanism extend further, to engage the strand, if desired. 
         [0139]    An additional advantage of this configuration is that subsequently tethered cannulas can be engaged and captured without risking of losing the first strand from the first tether. This is because the first tether is always blocked from escaping the engagement feature by either the capture mechanism, a second outer cannula or a second narrow cannula. 
         [0140]      FIG. 21  shows an alternative embodiment of the engagement mechanism. In this arrangement, the penetrating member  4   a  includes an engagement feature  12   a  which is “V” shaped. The capture mechanism  4   a  is a hook-like device which, in the state shown and when retracted, can capture the tethered cannula positioned in transverse alignment with the engagement feature  12   a . The “V” shaped engagement feature of the penetrating member is less likely to catch tissue as it passes through, so there is less need to block the engagement feature during penetration or withdrawal, as is contemplated with the preferred embodiment. As with the preferred embodiment, the penetrating member  3   a  is again preferably made from a cannula where the section  13   a  is flattened into an oval cross section in order to maximize the available geometry of the engagement feature  12   a.    
         [0141]      FIG. 22  shows the region  22  of  FIG. 21 . Upper portion of the penetrating member are slotted to provide a relief for the hook of the capture mechanism  4   a . This allows the dimensions of the hook to be optimized, within the confines of the penetrating member  3   a.    
         [0142]      FIGS. 23 and 24  show the hook retracted, in a position for capturing a tethered cannula located in the engagement region prior to retraction. It is to be noted that, as an alternative, the hook of the capture mechanism  4   a  can be oriented to face in the opposite direction as is shown in  FIGS. 23 and 24 , if desired, to instead face toward the distal tip and begin on the proximal side of the engagement feature. In such as an arrangement, the capture mechanism would extend toward the distal tip to engage a tethered cannula in a similar fashion as was described for the preferred embodiment. In addition, the capture mechanism  4   a  could be designed with two hooks, one hook facing distally toward the tip and another hook facing proximally away from the tip, so the tethered cannulas could be captured by either retracting or extending the hooks. 
         [0143]    As with the preferred embodiment, it is preferred that section  13   a  of the penetrating member  3   a  is flattened into an oval in the area of the engagement zone, instead of being round. As in the preferred embodiment, flattening a cannula in this region allows the engagement region to be of a larger dimension. As a further alternative, the entire cannula can be flattened, as well. 
         [0144]      FIGS. 25 and 26  show an alternative embodiment illustrating a penetrating member  3   b  having two engagement features  12   b . Such a configuration can be used to interact with a rotating capture mechanism, for example. To be noted is that while the two engagement features  12   b  are shown with the same overall configuration, it is also possible for the engagement features  12   b  to have different configurations, if useful for a particular application. 
         [0145]      FIGS. 27 to 30  show an alternative embodiment capture mechanisms  4   b  which is rotated by 90 degrees in each progressive figure, corresponding to the rotational capture mechanism  4   b  shown in  FIG. 31 . 
         [0146]      FIG. 32  shows the capture mechanism  4   b  inserted into the penetrating member  3   b , with the capture mechanism oriented as shown in  FIG. 28 . By progressively rotating the capture mechanism, in this case by 90 degrees, the two engagement features  12   b  can be selectively closed off from receiving a tethered cannula, or open to receive a cannula, and then closed off again to capture a tethered cannula or a strand in the forward section of either of the engagement features. 
         [0147]    In  FIG. 32 , the forward-most engagement feature  12   b , closest to the distal tip of  3   b , is shown in the open configuration, ready to receive a tethered cannula within the forward notch of the engagement feature, which is available to receive a narrow cannula. 
         [0148]    In  FIG. 33 , the capture mechanism  4   b  is rotated by 90 degrees, as shown in  FIG. 29 . In this orientation, a narrow cannula or strand (not shown) are captured in the forward notch of the engagement feature if present in the notch before rotation. In this orientation, the rear-most engagement feature  12   b , which is farther from the distal tip, is open to receive a second tethered cannula. 
         [0149]    In  FIG. 34 , the capture mechanism  4   b  is rotated by another 90 degrees, as is shown in  FIG. 30 . In this orientation, the forward notches of both of the engagement features  12   b  have openings where a narrow cannula or strand can be captured by the capture mechanism  4   b.    
         [0150]      FIGS. 35 and 36  show an alternative embodiment capture mechanism  4   c  having a flexible latch. The latch is preferably made from a flexible wire, in the configuration shown. However, other constructions can also be developed, if appropriate for a particular application. The curvature of the latch in the vicinity of the engagement feature  12   c  provides a smooth transition on the outer surface of the penetrating member  3   c , to prevent tissue from being snagged by the engagement feature. The guard  25   c  is shown in a forward position, which prevents the latch from opening by making it difficult to flex.  FIGS. 37 and 38  show the capture mechanism  4   c  with the guard  25   c  retracted, which then allows the capture mechanism  4   c  to flex, for opening the engagement feature  12   c .  FIGS. 39 and 40  show the capture mechanism  4   c  bent down to open the engagement feature  12   c  for receiving a tethered cannula or a strand. If desired, the capture mechanism  4   c  can be configured with a preferential bend so that when the guard  25   c  is retracted the capture mechanism  4   c  bends inwardly as shown, or the flexible capture mechanism  4   c  can be configured to bend outwardly, to continue to block the engagement feature with the guard  25   c  until it is bent inwardly by a force applied to it from a tethered cannula or a strand. 
         [0151]      FIGS. 41 and 42  show a further alternative embodiment of a capture mechanism  4   d  and a guard  25   d . In this embodiment, the guard  25   d  is fixed and preferably cooperates with the capture mechanism  4   d  when placed in alignment with the guard  25   d . While the capture mechanism  4   d  is shown as a flexible wire, other constructions can also be implemented. Alignment of the capture mechanism  4   d  with the guard  25   d  can be achieved by reciprocating the capture mechanism  4   d , by rotating the capture mechanism  4   d  or by configuring the capture mechanism  4   d  to bend out of the way responsive to a force applied to the capture mechanism  4   d . For example,  FIGS. 43 and 44  show the capture mechanism  4   d  being bent inwardly, as would occur responsive to a force applied to it, for example, from a tethered cannula or a strand, which could then enter the engagement feature  12   d . As a further alternative, the capture mechanism  4   d  can be retracted to provide an opening for the engagement feature, instead of using a capture mechanism  4   d  which is flexible. 
         [0152]      FIGS. 45 and 46  show an alternative embodiment capture mechanism  4   e  and guard  25   e . The guard  25   e  is fixed and provides a surface for receiving the capture mechanism  4   e . The capture mechanism  4   e  is shown as a small diameter wire, but can also be made from other thin-shaped materials supportable between the upper surface of the guard  25   e  and the penetrating member  3   e . In the configuration shown, the capture mechanism  4   e  is retractable, and both engagement features  12   e  are available to receive a tethered cannula or a strand. 
         [0153]      FIGS. 47 and 48  show the capture mechanism  4   e  of  FIGS. 45 and 46  advanced so that the rear or proximal engagement feature  12   e  is closed. A tethered cannula or a strand located in the rear engagement feature  12   e  before such advancement would then be captured between the capture mechanism  4   e  and the rear engagement feature  12   e .  FIGS. 49 and 50  show the capture mechanism  4   e  advanced further, so that a tethered cannula or a strand present in the forward (or distal) engagement feature  12   e  would similarly be captured as previously described. 
         [0154]      FIGS. 51 and 52  show an alternative embodiment engagement mechanism  11   f  and capture mechanism  4   f . The capture mechanism  11   f  is formed as a flexible hook, and is preferably made from a wire, although other constructions are also possible. The penetrating member  3   f  includes a slot through which the capture mechanism  4   f  can pass, by flexing outwardly responsive to a force applied by a tethered cannula or strand entering the engagement feature  12   f .  FIGS. 53 and 54  show the capture mechanism  4   f  flexing outwardly through the slot. Once the tethered cannula or strand is moved to the forward notch of the engagement feature  12   f , the capture mechanism  4   f  returns to the position shown in  FIG. 51  to capture the tethered cannula or strand. In such embodiments, it is advantageous for the capture mechanism  4   f  to normally flex inwardly. The guard  25   f  in this embodiment is shown to provide a surface for the capture mechanism  4   f  to abut against when inwardly positioned, as shown in  FIG. 52 . 
         [0155]      FIGS. 55 and 56  show an alternative embodiment engagement mechanism  11   g  and capture mechanism  4   g . The capture mechanism  4   g  includes a flexible hook which is preferably bent so the hook will elevate through a slot formed in the penetrating member  3   g . A guard could also be used to force the capture mechanism  4   g  outwardly, through the slot in the penetrating member  3   g , if desired. FIGS.  57  and  58  show the capture mechanism  4   g  in an outwardly directed position. A tethered cannula in the engagement feature  12   g  will flex the guard over the tethered cannula and then capture the tethered cannula with the hook in the engagement feature  12   g.    
         [0156]      FIG. 59  shows an alternative embodiment capture mechanism  4   h  and penetrating member  3   h , with the capture mechanism  4   h  retracted within the penetrating member  3   h . Advancing the capture mechanism  4   h , as shown in  FIGS. 60 and 61 , creates an engagement feature  12   h  between the penetrating member  3   h  and the capture mechanism  4   h , in a position ready to receive a tethered cannula or a strand.  FIGS. 62 and 63  show the capture mechanism  4   h  partially retracted into the penetrating member  3   h , in a position where a tethered cannula or strand is preferably captured, for example, by deflecting the capture mechanism  4   h  away from the engagement feature  12   h.    
         [0157]      FIG. 64  shows an alternative embodiment capture mechanism  4   h ′ retracted in a penetrating member  3   h ′ having a beveled point rotated 180 degrees from the orientation shown in  FIG. 60 . In this embodiment, the capture mechanism  4   h ′ is again shown as a flexible wire, although other flexible constructions can also be implemented, if desired.  FIGS. 65 and 66  show the capture mechanism  4   h ′ in an extended position, forming an engagement feature  12   h ′ between the penetrating member  3   h ′ and the capture mechanism  4   h ′. In this configuration, the engagement feature  12   h ′ is open and ready to receive a tethered cannula or a strand.  FIGS. 67 and 68  show the capture mechanism  4   h ′ retracted into the penetrating member  3   h ′, in a position where a tethered cannula or strand is preferably captured, for example, by deflecting the capture mechanism  4   h ′ away from the engagement feature  12   h′.    
         [0158]      FIG. 69  shows an alternative embodiment engagement mechanism  11   i  which includes a penetrating member  3   i  having a helical coil section. Multiple engagement features  12   i  are developed between the helical coils. For purposes of simplicity, only the engagement features are identified on the top side of the penetrating member  3   i , even though additional engagement features are available between the helical coils from the bottom side of the penetrating member  3   i . The capture mechanism  4   i  is shown with a bullet nose in the front, and is retracted relative to the engagement features  12   i , which are then open and available for transverse engagement with a tethered cannula or strand. Other configurations for the tip of the capture mechanism  4   i  are also possible, although the angled tip of the preferred embodiment is presently considered preferred to facilitate the capture of a larger diameter tethered cannula. 
         [0159]      FIG. 70  shows the capture mechanism  4   i  inserted through the engagement features  12   i  of the helical coils of the penetrating member  3   i . As previously indicated, a tethered cannula or a strand can be positioned between and within one of the engagement features  12   i  defined by the helical coils. An advancing capture mechanism  4   i  can come in contact with and capture a tethered cannula or strand. By using a suitably narrow cannula, the tip of the capture mechanism  4   i  can capture the cannula between the coils. The dimensions of the capture mechanism  4   i  can be selected to be sufficiently small to allow the capture mechanism to continue to advance, or to stop on the narrow cannula until the narrow cannula is withdrawn and a strand is captured between the bottom surface of the capture mechanism  4   i  and the helical coils. It is preferred that the dimensions of the capture mechanism  4   i  are sufficiently small relative to the inner dimensions of the helical coils to allow a strand to pass freely while captured. Alternatively, the helical coils could be made flexible, to expand by flexing as the capture mechanism captures the strand, although this is not presently considered to be the preferred configuration for this. 
         [0160]      FIGS. 71 ,  72  and  73  show an alternative embodiment engagement mechanism  11   j  which is similar in function to the engagement mechanism  11   c  shown in  FIGS. 35 and 36 . The penetrating member  3   j  includes an engagement feature  12   j . The capture mechanism  4   j  is shown constructed of a flexible wire but, as previously indicated, can be of some other construction. The guard  25   j  in the position shown in  FIG. 71  prevents the capture mechanism  4   j  from flexing inwardly to prevent a tethered cannula or strand from entering the capture zone of the engagement feature.  FIG. 72  shows the guard  25   j  retracted and the capture mechanism  4   j  in a position in which a downward force applied from a tethered cannula or a strand will cause the capture mechanism  4   j  to flex inwardly to open the engagement feature for receiving a narrow tethered cannula or a strand, as is shown in  FIG. 73  (tethered cannula or strand not shown). To be noted is that the front end of the guard  25   j  can be angled, as shown, to lift a narrow cannula or a tether into the forward slot of the engagement feature. 
         [0161]      FIGS. 74 ,  75 ,  76  and  77  show an alternative embodiment engagement mechanism  11   k  which illustrates a capture mechanism  4   k  having multiple engagement features  12   k . The illustrated penetrating member  3   k  is made from a cannula with a flattened distal tip, to again provide the advantage of allowing larger dimensions for the engagement features.  FIG. 74  shows the capture mechanism retracted.  FIG. 75  shows the capture mechanism extended to receive a tethered cannula or a strand.  FIG. 76  shows the proximal engagement feature  12   k  retracted to a position where a first tethered cannula or strand would be captured, leaving the distal engagement feature  12   k  available to receive another tethered cannula or strand, if desired.  FIG. 77  shows the capture mechanism  4   k  retracted to a position where a tethered cannula or strand can be captured in either or both of the engagement features  12   k.    
         [0162]      FIGS. 78 ,  79 ,  80  and  81  show an alternative embodiment engagement mechanism  11   k ′ which is similar to the engagement mechanism  11   k  in  FIGS. 74 to 76 . The penetrating member  3   k ′ is shown with a pointed tip oriented with the bevel rotated 180° relative to the tip shown in  FIGS. 74 to 76 . In this orientation, as shown in  FIG. 81 , the proximal engagement feature  12   k ′ is behind the penetrating member  3   k ′ when the capture mechanism  4   k ′ is retracted to this position. With this arrangement, a tethered cannula could not be fully retracted to this position if located in the slot of the proximal engagement feature  12   k ′. However, a strand would be able to bend between the capture mechanism  4   k ′ and the penetrating member  3   k ′ if a sufficient gap is provided between the capture mechanism  4   k ′ and the penetrating member  3   k ′ for a given strand thickness and bend radius. 
         [0163]      FIGS. 82 ,  83 ,  84  and  84  show an alternative embodiment engagement mechanism  11   k ″ which is similar to the engagement mechanisms  11   k  and  11   k ′. In this embodiment, the penetrating member  3   k ″ is shown with a contoured tip. The advantage of this arrangement is best illustrated in  FIG. 85 , which shows the capture mechanism  4   k ″ retracted to a position where tethered cannulas or strands positioned in transverse alignment within the engagement features  12   k ″ prior to retraction, could be captured in the engagement features. In this position, the engagement features  12   k ″ are not fully blocked by the penetrating member  3   k ″, which enables the tethered cannulas to be captured, and for the strands to be captured without necessitating bending of the strand between the walls of the capture mechanism and the penetrating member. This has the advantage of capturing a strand without exposing the strand to cutting forces that could occur if the strand is forced against a sharp bevel, either by retraction of the capture mechanism or by the insertion or withdrawal of the penetrating member with a strand present in a captured engagement feature. In  FIG. 85 , the engagement feature  12   k ″ in the distal position is in a location where a captured strand would not encounter a cutting force from a sharp edge of the penetrating member  3   k ″ during subsequent insertion or extraction of the penetrating member  3   k ″ along its axis. 
         [0164]      FIGS. 86 and 87  show an alternative embodiment engagement mechanism  11   l  which is similar to the engagement mechanism  11   c  shown in  FIGS. 35 and 36 , except that there is no guard and the capture mechanism  4   l  is a latch capable of flexing to provide access to the engagement feature  12   l  when an inwardly directed force from a tethered cannula or strand is applied against it, as is shown in  FIG. 87  (tethered cannula or strand not shown. In this embodiment, when a narrow tethered cannula or strand slides into the forward horizontal notch of the engagement feature, the latch releases and returns to the position shown in  FIG. 86 , and the tethered cannula or strand is captured in the engagement feature by the latch. 
         [0165]      FIGS. 88 and 89  show an alternative embodiment engagement mechanism  11   m  including a penetrating member  3   m  with an engagement feature  12   m  having a capture mechanism  4   m  which is inflatable.  FIG. 88  shows the capture mechanism  4   m  deflated, with the engagement feature  12   m  open to receive a tethered cannula or strand.  FIG. 89  shows the capture mechanism  4   m  inflated, for example, with a fluid or a gas, through an inflation tube  26   m , which then closes of the engagement feature. As shown in  FIG. 89 , a tethered cannula or strand in the forward notch of the engagement feature  12   m  would be captured by the inflated capture mechanism. 
         [0166]      FIGS. 90 and 91  show an alternative embodiment engagement mechanism  11   n  including a penetrating member  3   n  with an engagement feature  12   n . The capture mechanism  4   n  and the guard  25   n  are attached to a control rod  27   n .  FIG. 90  shows the control rod  27   n  in a forward position, in which the guard  25   n  will close off the engagement feature  12   n  from receiving a tethered cannula or strand.  FIG. 91  shows the control rod retracted, with the capture mechanism  4   n  flexing inwardly, responsive to an inwardly directed force exerted by a tethered cannula or strand on the capture mechanism  4   n  (tethered cannula or strand not shown). As the tethered cannula or strand then moves into the forward notch of the engagement feature  12   n , the capture mechanism  4   n  will flex outwardly and capture the tethered cannula or strand within the engagement feature  12   n.    
         [0167]      FIGS. 92 and 93  show an alternative embodiment engagement mechanism  11   o  including a penetrating member  3   o , which is shown as a cannula with engagement features  12   o , and a capture mechanism  4   o  including a coil spring which resides in the penetrating member  3   o . In  FIG. 92 , the coil spring is attached to a fixation location  280 . In this configuration, multiple engagement features  12   o  are shown between the coils in the section of the penetrating member having a relief in the penetrating member  3   o . For the case where the spring is a tension spring, if the spring is under tension the gap between the exposed coils will widen, and the engagement features  12   o  will be available to receive a tethered cannula or strand. In  FIG. 93 , the capture mechanism  4   o  is shown with the coil spring no longer in tension. In this configuration, the pitch between the spring coils is selected to capture a tethered cannula or strand between the coils. If needed, an additional compressive force can be applied to the spring to further compress the coils and capture a tethered cannula or strand. The spring used with the capture mechanism  4   o  can also be a compression spring, rather than a tension spring, and in such case would initially be open to receive a tethered cannula or strand, as shown in  FIG. 92 , followed by the application of a force to the spring to compress it for capturing a tethered cannula or strand, as shown in  FIG. 93 . 
         [0168]      FIGS. 94 and 95  show an alternative embodiment engagement mechanism  11   o ′. As with engagement mechanism  11   o , a capture mechanism  4   o ′ includes coils with a fixation location  29   o ′, and the device functions in a similar manner to the engagement mechanism  11   o ′, with the main difference being that the coils in capture mechanism  4   o ′ are wrapped around the outside of the penetrating member  3   o ′ instead of being located inside the penetrating member  3   o  described in  FIGS. 92 and 93 . For the engagement mechanism  11   o ′, the penetrating member  3   o ′ can be solid, if desired. 
         [0169]      FIGS. 96 and 97  show an alternative embodiment engagement mechanism  11   o ″ including a penetrating member  3   o ″ and a capture mechanism  4   o ″ which includes a coil.  FIG. 96  shows plural engagement features  12   o ″ which are produced between the coils protruding from the distal tip of the penetrating member  3   o ″. In this state, the engagement features  12   o ″ are available to receive a tethered cannula or a strand.  FIG. 97  shows the capture mechanism  4   o ″ partially retracted. A strand residing in an engagement feature  12   o ″ will be caught between the coils and the interior of the penetrating member  3   o ″ as the capture mechanism is retracted inside the penetrating member. 
         [0170]      FIG. 98  is a plan view of an engagement mechanism  11   p  having a penetrating member  3   p  with an engagement feature  12   p  and a capture mechanism  4   p  which includes a small brush in the region of the engagement feature. The brush is designed to rotate inside the penetrating member. With a strand positioned in transverse alignment in the engagement feature, against the brush, the brush is rotated to capture the strand by winding it around the brush. The strand can be initially positioned at the engagement feature with a tethered cannula, and if so, the tethered cannula must be withdrawn to expose the strand directly to the brush of the capture mechanism  4   p.    
         [0171]      FIGS. 99 ,  100 ,  101  and  102  are plan views of an engagement mechanism  11   q  having a penetrating member  3   q  and a capture mechanisms  4   q  including a series of telescoping pieces that can be positioned axially to create engagement features  12   q  between one or more capture mechanisms  4   q  or between a capture mechanism and the penetrating member. A tethered cannula or strand can be positioned in one of the engagement features  12   q  and then captured by the movable telescoping capture mechanism  4   q .  FIGS. 99 to 102  show an example of the progressive positioning of several telescoping capture mechanisms  4   q . In this illustration, as one telescoping capture mechanism advances to capture a tethered cannula or strand in the engagement region  12   q  distal to the capture mechanism, another engagement region emerges proximally behind it. 
         [0172]      FIGS. 103 ,  104  and  105  are plan views of an engagement mechanism  11   r  including a penetrating member  3   r  with engagement features  12   r  and a capture mechanism  4   r . The capture mechanism  4   r  includes two hook-shaped regions, one facing forward and one facing rearward.  FIG. 103  shows the capture mechanism in a forward position with an engagement feature  12   r  defined between the rear hook area and the rear of the relief in the penetrating member  3   r . In this position, the apparatus is ready to receive a tethered cannula or strand in the rear-most open engagement feature  12   r . In  FIG. 104 , the capture mechanism is retracted, which captures a tethered cannula or strand in the rear engagement feature  12   r  shown in  FIG. 101  and opens up another engagement feature  12   r  in the front of the forward facing hook of the capture mechanism.  FIG. 105  shows the capture mechanism  4   r  partially advanced to a central position so that both of the engagement features  12   r  from  FIGS. 103 and 104  are closed. 
         [0173]      FIGS. 106 and 107  are plan views of an engagement mechanism  11   s  including a penetrating member  3   s , a capture mechanism  4   s  which includes a magnet, and a strand  20   s  which includes magnetically attractive particles, such as beads. If the attraction between the magnet and the magnetically attractive particles are strong enough, it is possible that no other engagement features are required.  FIG. 107  shows the strand magnetically coupled with the magnetic capture mechanism  4   s.    
         [0174]    In order to reduce the amount of magnetic attraction required, it may be advantageous to use a penetrating member  3   s  with an engagement feature coupled with a magnet. For example, a magnet could be used in place of the coil shown in  FIGS. 96 and 97  for the capture mechanism, and the magnetic capture mechanism  4   s  could extend from the distal tip of the penetrating member, contact a magnetically attractive strand in transverse alignment and then, with a magnetic coupling, pull the strand through the penetrating member when the penetrating member is hollow, or retain the strand with the magnetic coupling at the tip of the penetrating member. A magnetic capture mechanism could also capture a strand using magnetically attractive particles within an engagement feature defined by a slot or relief in a penetrating member at a location which is not at the tip. 
         [0175]      FIG. 108  is a plan view of an engagement mechanism  11   t  including a penetrating member  3   t  with an engagement feature  12   t  and a capture mechanism  4   t  having a compressible foam-like or rubber-like material. A force applied by a tethered cannula or strand at the engagement feature  12   t  will compress the capture mechanism and allow the tethered cannula or strand to slip into the horizontal forward notch of the engagement feature. 
         [0176]      FIGS. 109 and 110  show an engagement mechanism  11   u  including a penetrating member  3   u  with an engagement feature  12   u  and a capture mechanism  4   u  formed of a flexible material, such as a wire, that is bent and fixed in position so that when a tethered cannula or strand is forced inwardly into the engagement feature, the capture mechanism deforms and then snaps around the tethered cannula or strand. 
         [0177]      FIGS. 111 and 112  show an engagement mechanism  11   v  including a penetrating member  3   v  with an engagement feature  12   v  and a capture mechanism  4   v  having jaws that can be opened or closed to receive a tethered cannula or strand. 
         [0178]      FIGS. 113 and 114  show an engagement mechanism  11   w  including a penetrating member  3   w  with an engagement feature  12   w  and a capture mechanism  4   w  having a flexible member with barbs.  FIG. 113  shows the capture mechanism  4   w  retracted and the engagement feature  12   w  open to receive a tethered cannula or strand.  FIG. 114  shows the capture mechanism  4   w  extended to capture a tethered cannula or strand. 
         [0179]      FIGS. 115 and 116  show an engagement mechanism  11   x  including a penetrating member  3   x  with an engagement feature  12   x  and a capture mechanism  4   x  including a spring loaded ball.  FIG. 115  shows the spring extended and the engagement feature  12   x  closed off by the ball.  FIG. 116  shows the ball retracted and the engagement feature  12   x  open to receive a tethered cannula or strand. The spring loaded ball can either be retracted axially by the user, or passively retracted with the application of an inward force produced by a tethered cannula or strand, at the engagement feature and against the front half of the ball. 
         [0180]      FIGS. 117 and 118  show an engagement mechanism  11   y  including a penetrating member  3   y  with an engagement feature  12   y  and a capture mechanism  4   y  which includes a sheath. In  FIG. 117 , the sheath  4   y  is extended over the engagement feature, closing it off and preventing it from receiving a tethered cannula or strand.  FIG. 118  shows the sheath  4   y  retracted and the engagement feature  12   y  open to receive a tethered cannula or strand. The sheath  4   y  can also be partially extended to capture a tethered cannula or strand in the narrow horizontal notch of the engagement feature  12   y.    
         [0181]      FIGS. 119 and 120  show an engagement tool  1   z  including a fluid pathway  30   z  for dispensing fluid through the tool, which can be useful to administer anesthetic fluids for numbing tissue, and saline solutions for opening pathways through tissue by hydro-dissection. This can be especially useful if the tip of the penetrating member is blunt. 
         [0182]      FIG. 121  shows a preferred embodiment of a routing tool  30  which can be used to position a tethered cannula or strand in transverse alignment with an engagement tool. The preferred embodiment includes a body  31  coupled with a penetrating member  32 . The penetrating member  32  is shown with a pointed tip, which can optionally be provided. A blunting mechanism  33  is also preferably provided, and is coupled to a carriage  36  which causes the blunting mechanism  33  to translate along the axis of the penetrating member  32  to blunt the distal tip of the penetrating member  32 , as is described, for example, in the above-referenced U.S. patent application Ser. No. 12/384,326, and International Application No. PCT/US2010/000891. 
         [0183]    An actuator mechanism  34  is provided which, as shown in  FIG. 121 , is in a raised position. When the actuator mechanism  34  is depressed, it rotates around a pivot point and teeth on the actuator mechanism engage a gear  35 , which engages the linear teeth of the carriage  36  and causes the carriage and the coupled blunting mechanism  33  to advance toward the distal tip of the penetrating member  32 . When the carriage advances past a certain point, a flexible arm shown toward the rear of the carriage engages the small teeth of a rotating ratchet  38 , rotating the large teeth of the ratchet  38  and allowing the latch  39  to flex or spring downward into a position which prevents the carriage  39  from returning, and compressing a spring mechanism  37  for keeping the carriage engaged against the front of the latch mechanism  39 . This ensures that the blunting mechanism is latched into a blunt position, and that a force applied on the tip of the blunting mechanism  33  which extends past the tip of the penetrating member will be resisted by the latch  39  and will not result in the blunting mechanism retracting and exposing the sharp tip. In this state, the compressed spring  37  causes the actuator arm to partially rotate back from its fully depressed position when the actuator arm  34  is released. However the actuator arm  34  is not allowed to fully return to its top-most position because of the latch. Partial return of the carriage allows the flexible arm to travel slightly behind the ratchet mechanism  38  while the blunting mechanism is maintained slightly forward of the tip of the penetrating member  33  and slightly back from a fully forward position. Subsequent depression of the actuator  34  toward a fully forward position causes the rear arm on the carriage to again engage the small teeth of the ratchet  38  to rotate, causing the large teeth of the ratchet  38  to engage the latch  39  and raise it to a position where the carriage  35  is free to return to a rearward position from the force of the compressed spring  37 , causing the actuator  34  to raise fully and the blunting mechanism  33  to retract, and exposing the pointed tip of the penetrating member  32 . Also shown is an indicator  40  which is intended to remain above the tissue and provide an indication of the location of the distal tip of the penetrating member when hidden from view by tissue. 
         [0184]      FIG. 122  shows the region  122  shown in  FIG. 121  of the front end of the penetrating member  32 . In this embodiment, the front end  42  includes the distal tip  32  of the penetrating member, which is shown as a sharp tip having a bevel which is bent slightly inwardly toward the axis of the penetrating member, which is constructed from a cannula. In this embodiment, the blunting mechanism is a cannula  33  which translates inside of the penetrating member. The blunting mechanism is shown in a retracted position, with the sharp tip of the penetrating mechanism exposed. A strand  41  is coupled to the blunting mechanism and forms a loop for subsequent coupling with the strand of a tethered cannula or to a strand not attached to a cannula. The strand  41  preferably passes through two small slots in the blunting mechanism  33 , and ends of the strands are retained by the blunting mechanism, preferably by the knots  43  shown, which prevent the strand  41  from being pulled through the slots. The penetrating member  33  preferably includes one or more slots which are aligned with the slots of the blunting mechanism. The slot or slots in the penetrating member  33  are sufficiently long to allow the strand  41  to translate when the blunting mechanism translates from its forward-most position to its rear-most position responsive to operations of the mechanisms associated with the routing tool  30 , as previously described. 
         [0185]      FIG. 123  shows the routing tool  30  with the actuator  34  depressed and in the latched forward position, where the blunting member  33  extends forward of the distal tip of the penetrating member  32 . The spring  37  is shown compressed and the latch  39  is shown engaging the carriage  36 , which prevents the carriage from fully returning. The ratchet mechanism  38  is shown rotated in a position where the larger teeth of the ratchet allow the latch  39  to lower into the latching position, and the rear arm of the carriage which engages the small teeth of the ratchet  38  is shown just rear of the small teeth of the ratchet.  FIG. 124  shows the region  124  of  FIG. 124 . In this configuration, the outer diameter of the blunting mechanism  33  extends forward of the tip of the penetrating member  32  and contacts the bent tip of the beveled point of the penetrating member so that the tip does not act as a catch point. 
         [0186]      FIG. 125  shows the routing tool  30  coupled with a tethered cannula  24 , through the looped strand  41  of the routing tool and the strand  20  of the tethered cannula  24 . By inserting the routing tool through tissue, a pathway is created. A separate strand can be coupled to the routing tool and positioned along this same pathway. In this way, coupling occurs by passing a strand through the loop  41  of the routing tool. Other techniques can also be used to couple a strand to the routing tool, if desired, such as inserting the strand through the lumen of the routing tool, or tying a strand to the routing tool directly or through a strand affixed to the routing tool, or mechanically engaging the strand to the routing tool.  FIG. 126  shows the region  126  of  FIG. 125 , showing the strand  20  passing through the loop of the strand  41 . 
         [0187]    The routing tool can conveniently be coupled with a strand and, when used in conjunction with the engagement tool previously described, can be used to subcutaneously manipulate strands into various configurations, including desirable loops for supporting tissue or for severing an internal structure, such as a ligament. The routing tool shown is advantageously used by inserting it through tissue and then coupling it with a tethered cannula. This can be repeated several times, if desired, to position multiple tethered cannulas through tissue for subsequent engagement by the engagement tool, as previously described. 
         [0188]    It is also possible to have the routing tool provide the initial engagement with the engagement tool by positioning the routing tool and the engagement tool in transverse alignment at the engagement feature of the engagement tool. In this configuration, subsequently coupling a strand to the routing tool can facilitate the direct coupling of the strand to the engagement tool without necessitating a separate tethered cannula. Previously, it had been indicated that a strand under tension could be advantageously used to fully engage and capture the strand in many of the described engagement mechanisms. A strand coupled with the routing tool can be held in tension to facilitate this engagement. In this arrangement, once the routing tool is coupled to the strand, the combination of the strand and the routing tool can be considered as another embodiment of a tethered cannula. 
         [0189]      FIGS. 127 ,  128  and  129  show an alternative embodiment routing tool which can also be considered a tethered cannula, and which can facilitate a more direct engagement with an engagement tool. Instead of including a strand  41  to engage a subsequent strand, the routing tool includes a strand  20   a , which is shown in the front end  42   a  of the penetrating member  32   a . For embodiments where the penetrating member  32   a  includes a sharp point, the blunting mechanism  33   a  is preferably included and the strand  20   a  can pass through it if it is constructed from a cannula. With the blunting mechanism  33  extended, as shown in  FIG. 128 , the diameter of the blunting mechanism can act as a narrow cannula and can extend farther than is shown in  FIG. 128 . This enables the routing tool to engage the engagement tool in similar fashion to a tethered cannula, where the initial engagement can occur with an outer cannula, in this case the penetrating member  32   a . Progressive engagement and capture can then occur with a narrow cannula, in this case, the extended blunting cannula  33   a , followed by final engagement with the strand  20   a.    
         [0190]    In the embodiments shown, the strand  20   a  includes a tip  44   a . This tip  44   a  can be a long continuation of the strand which extends along the outside of the penetrating member, or it can be an obstructive member, such as a knot, having a sufficient size to be retained by the engagement feature of the engagement tool after it is captured. As a further alternative, magnetic particles can be provided to facilitate engagement and capture by an engagement tool with a magnet in the engagement feature. While the illustrated mechanism is shown with several elements, the front end  42   a  of the penetrating member of the routing tool can also be implemented with a tethered cannula having a blunt cannula, with a strand  20   a  coupled with the tip  44   a.    
         [0191]    The primary advantage of the arrangement shown in  FIGS. 127 ,  128  and  129  is that the routing tool does not have to exit from the tissue to couple with a separate tethered cannula. Instead, it can couple directly with the engagement tool inside the tissue, which can be an advantage when further penetration of the routing tool by the penetrating member is obstructed or undesirable. 
         [0192]      FIGS. 130 and 131  show an alternative embodiment routing tool  30   b . In this configuration, the routing tool  30   b  includes a fluid pathway  45   b  for dispensing fluid through the tool. This can be useful for the administration of anesthetic fluids for numbing tissue and saline solutions for opening pathways through tissue, for example, through hydro-dissection, which is especially useful with penetrating members having blunt tips. 
         [0193]    It will be understood that while the present invention has been described based on specific embodiments incorporating specified parts, the present invention further encompasses all enabled equivalents of the parts described, and that various changes in the details, materials and arrangement of parts which have been herein described and illustrated in order to explain the nature of this invention may be made by those skilled in the art within the principle and scope of the invention as expressed in the following claims.