Patent Publication Number: US-2016220259-A1

Title: Delivery of a Clamping Implant Via a Puncture

Description:
FIELD AND BACKGROUND OF THE INVENTION 
     The invention relates to a tool, a system and a method for delivering and applying a clamping implant via a puncture in skin tissue and underlying tissue. The proposed tool, system and method are particularly suitable for closing off varicose veins, in particular the Great Saphenous Vein and the Small Saphenous Vein by clamping off. However, the proposed device, system and method can also be used for other treatments involving applying a clamp in tissue in a position spaced under the skin, such as embolization or clamping of a biliary duct, a ureter, a Fallopian tube, etc. 
     Conventionally, such treatments include surgical interventions to create space for movement of the clip and the clip application tool in the tissue surrounding the hollow structure to be closed off. It is particularly challenging to achieve this with little tissue damage when approaching a tubular hollow structure in a direction about perpendicular to the longitudinal axis of that tubular structure. An alternative is not to create such free space, but to thread some cross stitches of surgical wire through the tissue. However a disadvantage of such an approach is that it frequently causes tears in the tissue, so that the tissue is still damaged. 
     More specifically, known surgical treatments of more-severe varicose veins that do not respond to self-care, include vein stripping (removing a long vein through small incisions), Ambulatory Phlebectomy (removal of smaller varicose veins using a hook through a series of 2-3 mm skin punctures), endoscopic vein surgery (a thin video camera inserted in the leg visualizes varicose veins, that are then closed off and removed through small incisions) and vein ligation (tying a piece of thread around the vein to shut it off). 
     In European patent application 2 599 450 a tool, a clip and a method for closing off a varicose vein is disclosed in which the clip is introduced to a location where the vein is to be closed by clamping via a needle punctured through the skin and through tissue between the skin and the vein to be treated. A problem associated with this method and device is that a substantial change in shape of the clip is required when the clip exits the needle, that, after exiting the needle, the clip has to be advanced through tissue surrounding the vein to be clamped and that after the deformation upon exiting the needle and having been advanced through tissue adjacent to the location where the vein is to be clamped, it has to be ensured that the clip exerts the clamping action required to close off the vein. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a simple solution that allows delivering a clamping implant through a patient&#39;s skin and through tissue under the skin in a minimally invasive manner, to a location spaced from the skin, where the clamping implant exerts a clamping action to tissue engaged by the clamping implant. 
     According to the invention, this object is achieved by providing a tool. The invention can also be embodied in a system, which comprises such a tool and a clamping implant, and in a method. 
     Because the needle has a longitudinal axis forming a helix, the needle can be punctured to the location where the clamping implant is to be delivered along a helix shaped puncture path. The plunger operating member engaging a proximal portion of the plunger projecting from the needle, for screwing the plunger further into or out of the needle by screwing rotation of the needle relative to the plunger and the coiled clamping implant, allows the clamping implant to be delivered from the needle at the delivery location by screwing back the needle, while restraining the plunger from being screwed back with the needle, so that the plunger is held essentially stationary relative to the tissue surrounding the helix shaped puncture path. The plunger effectively allows the clamping implant in a position at a distance underneath the skin surface to be restrained from being screwed back with the needle. 
     Deformation of the clamping implant can remain limited to deformation to a biased state inside the lumen of the needle and a gradual release from the biased state inside the lumen of the needle to a clamping state in which the clamping implant engages tissue clamped thereby, as the clamping implant exits the needle that is screwed out. 
     Other features of embodiments of the invention are set forth in the dependent claims. 
     Further objects, features, effects and details of the invention are described below with reference to embodiments shown in the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       While the appended claims set forth the features of the present invention with particularity, the invention, together with its objects and advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings of which: 
         FIGS. 1-5  are schematic representations of an example of a tool, a system and a method according to the invention in successive stages of operation; 
         FIG. 6  is a side view of a second example of a tool according to the invention; 
         FIG. 7  is a perspective exploded view of an example of a system according to the invention including a tool as shown in  FIG. 6 ; 
         FIG. 8  is a side view in cross-section along a center line of a system as shown in  FIG. 7  in an operating condition prior to delivery of a clamping implant; and 
         FIG. 9  is a side view according to  FIG. 8  of a tool as shown in  FIGS. 6-8  in an operation condition after delivery of a clamping implant. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIGS. 1-5  successive stages of operation of first examples of a tool, of a system, and of a method according to the invention are shown. In the present example, the application of the tool is for closing off a varicose vein  1  which is located in tissue  2  at a distance under skin tissue  3 . The distance between the vein and the skin is typically 1 to 3 cm. The diameter of the vein  1  is usually 10 mm or less. A closing device for closing off the vein  1  will usually have to be passed through the skin  3  and through slightly less than 1 to 3 cm of underlying tissue  2 . 
       FIGS. 1-5  also show the first examples of the tool and the system according to the invention in successive stages of operation. The tool is composed of a hollow needle  4  bounding a lumen  5  and having a longitudinal axis forming a helix, a plunger  6  (schematically represented as the fully black portion of the needle  4  proximally of to dash-and-dot line  10 ) of which a distal portion extends in longitudinal direction inside the lumen  5 , and a plunger operating member  7 . The plunger operating member  7  engages a proximal portion of the plunger  6  projecting proximally from the needle  4 , for screwing the plunger  6  further into or out of the needle  4  by screwing rotation of the needle  4  relative to the plunger  6  about an axis (center line)  8  of the helix. 
     In addition to the tool, the system further includes a clamping implant  9  in the form of a coiled wire. In  FIGS. 1-3 , the clamping implant  9  in a biased configuration inside a distal end portion of the needle  4  is schematically represented by a line distally of the dash-and-dot line  10  and coaxial with the distal end portion of the needle  4 . In  FIGS. 4 and 5 , the clamping implant  9  clamping the tissue  2  under the skin  3  in an area spaced from the skin is schematically represented by a side view of the coiled wire. Because the tissue is resilient, it is compressed by the clamping force exerted by the clamping implant. This causes the biased clamping implant  9  to be released from the biased shape in the needle to a partially released configuration in which the pitch between successive windings in axial direction (direction of the central axis  8 ) is substantially smaller than the pitch between successive windings in axial direction in the biased configuration. 
     The vein screw can be used to treat, for example, a varicose vein  1  in the Great Saphenous Vein and the Small Saphenous Vein. Prior to starting the procedure of delivering the clamping implant  9  to a location where the vein  1  is to be closed off, the location of the vein  1  is determined (e.g. using ultrasound) and for instance marked on the skin. The location may for instance be in the thigh near the inguinal area or in the popliteal fossa. The tissue  2  and the skin  3  into which the needle  4  is to be punctured are preferably locally anaesthetized. Then, the tool pre-loaded with a clamping implant  9  may be taken out of a packaging for keeping the tool sterile. Then, the system composed of the tool and the clamping implant  9  in a distal end portion of the needle  4  is positioned with a distal end of the needle at the determined location on the skin  3 , preferably in an orientation about perpendicular to the skin, as illustrated by  FIG. 1 . 
     Next, the needle  4  is punctured into and through the skin tissue  3  and into underlying tissue  2  along a helical path corresponding to the helical shape of the needle  4  as is shown in  FIG. 2 . This is continued, preferably under ultrasound guidance, until the clamping implant has reached a position having portions (preferably at least a full winding) distally and proximally of the vein  1  to be clamped as is shown in  FIG. 3 , e.g. so that it encloses the vein  1  close to the junction with the deep femoral vein. 
     Then, the needle  4  is removed by screwing back the needle  4  along the helical path  26  through the tissue  2  underlying the skin tissue  3  (see  FIGS. 4 and 5 ). As the needle  4  is screwed back, the clamping implant  9  inside a distal end of the needle  4  is restrained against moving along with the needle  4 , preferably by holding the operating member  7  engaging a proximal portion of the plunger  6  projecting from the needle  4  stationary, thereby screwing the plunger  6  further into the needle  4  as the needle  4  is screwed out. Thus, the plunger  6  urges the wire of the clamping implant  9  out of the needle  4  as the needle  4  is screwed out. 
     Within the framework of the invention, the plunger  6  may also be used to advance the clamping implant  9  out of the needle and into tissue, but preferably, the implant  9  is not pushed into tissue while projecting from the needle  4 . Pushing the implant  9  out of the needle  4  such that it pierces into the tissue would cause the leading end of the clamping implant  9  to determine the puncturing path, so that it would not be ensured that a path would be obtained in which the clamping implant  9  would have the desired compressing effect. Moreover, the clamping implant  9  would most likely not reach a position bridging the vein and would cause more tissue damage. 
     Because the needle  4  has a helical shape, the needle  4  can be punctured to the location where the clamping implant  9  is to be delivered along a helix shaped puncture path. The coiled clamping implant  9  can be delivered from the needle  4  at the delivery location by screwing back the needle  4  and urging the clamping implant  9  out of the needle  4  by the plunger  6  as the needle  4  is screwed back. Deformation of the clamping implant  9  can remain limited to deformation to a biased state inside the lumen  5  of the needle  4  and a gradual release from the biased state inside the lumen  5  of the needle  4  to a clamping state in which the clamping implant  9  engages tissue  2  clamped thereby, as the clamping implant  9  exits the needle  4 . 
     In an unloaded condition, the plunger  6  may have the same pitch as the needle  4  to keep friction between the plunger  6  and the needle  4  low. The helical needle  4  is minimally invasive because the tissue damage is limited to a helical pathway  26 . For minimizing tissue damage, it is advantageous that the pitch of the needle  4  is constant over its length. The tissue  2  adjacent to the vein  1  is resilient, allowing the clamping member  9  to spring back to some extent to a less biased shape as it exits the needle  4 , thereby gradually compressing the tissue  2  and pressing the vein  1  to a virtually closed condition so that at least a substantial occlusion of the vein  1  is obtained. Compression of the tissue occurs in a gradual manner and can be controlled by controlling screwing back of the needle  4 . 
     While in the present example, a clamping implant  9  is shown which, when inserted in the needle  4  is biased such that essentially only the pitch in longitudinal direction of the central axis  8  of its helical shape is extended and reduced when the clamping implant  9  is released from its biased shape. However, it is also possible to provide that in addition or as an alternative, the diameter of the helical axis of the clamping implant  9  reduces when the clamping implant  9  is released from its biased shape. The axial and radial bias may also vary over the length of the coil, for instance to provide that the clamping implant  9  is of a spiral shape over its entire length or over a portion of its length. The clamping implant  9  may for instance be arranged to spring or otherwise move to a configuration in which the diameter of the windings decreases towards its ends, so that the tissue volumes engaged to be clamped together are also to some extent radially compressed, which enhances axial clamping action. Further, springing back after the clamping implant  9  has exited the needle  4  can also be achieved in other manners than by allowing elastic deformation to spring back. The clamping implant  9  may for instance be of a memory material that returns towards its original shape or of a material or material combination that deforms under influence of heat and/or contact with tissue liquids. 
     That relatively little deformation of the clamping implant  9  is required when it is delivered is particularly advantageous for applying implants of biodegradable material. Depending on the rate of decomposition of biodegradable material, temporary closures can be applied or permanent closures can be provided without permanently leaving a clamping implant  9  in the patient&#39;s body. 
     In biased condition inside the needle  4 , the clamping implant  9  has a length measured along the path of its wire that is shorter than the length of the needle  4  measured along the helical axis of the needle  4 . This difference in length allows the clamping implant  9  to be delivered and urged out of the needle  4  in a position in the tissue  2  in which its proximal end (the end facing the operating member  7 ) is spaced under the outer surface of the skin  3 . The clamping implant  9  may be a spring which, in unloaded condition has 2-4 windings and a pitch such that successive winding are in contact with each other, optionally with some pre-stress, as the windings of a double loop key ring. The implant  9  can be loaded in the needle  4  of a helical shape with a larger pitch under tension and will contract in the axial direction upon release. 
     In  FIGS. 6-9 , a second example of the tool and the system according to the invention is shown in more detail. In  FIGS. 8 and 9  cross-sections of the needle  104  through which the plunger  106  extends have been filled in with a thick black circle (ending at  110  in  FIG. 8 ), while in cross-sections of the needle  104  through which the clamping implant  109  extends (beginning at  110  in  FIG. 8 ), the cross sections of the clamping implant  109  are represented by small circles. In  FIG. 7 , the clamping implant  109  is shown in a condition as if inserted in the needle  104 , in which the helical axis of the clamping implant  109  has a diameter and a pitch between successive windings, in longitudinal direction of its central axis, that is equal to diameter and, respectively the pitch between successive windings, in longitudinal direction of the central axis, of the helical axis of the needle  104 . In the unloaded condition of the clamping implant  109 , its helical axis is of a shape in which at least the diameter or the pitch between successive windings, in longitudinal direction of its central axis is smaller than the diameter or, respectively the pitch between successive windings, in longitudinal direction of the central axis of the helical axis of the needle  104 . 
     In the present example, the plunger  106  has a length such that the plunger  106  is insertable into the needle  104  up to a position in which with its distal end reaches an opening forming a distal end of the lumen in the needle  104 . Thus, it can be ensured that the clamping implant can be urged out of the needle  104  and is not entrained with the needle  104  when the needle  104  is screwed out of the tissue. 
     However, in some cases a shorter plunger  106  may also be sufficient, for instance if it is ensured that frictional and/or interlocking engagement between tissue and the clamping implant  109  prevents the clamping member from being entrained with the needle  104  being screwed out of the tissue. Then, the plunger  106  may have a length such that the plunger  106  is at least insertable into the needle  104  beyond a proximal end of a clamping implant  109  fully inserted in a distal end portion of the needle  104 , so that it is ensured that the clamping member  109  can be urged actively over at least a portion of its length. For ensuring that the distance over which the clamping implant  109  can be urged out of the needle  104  by the plunger  106  is sufficient to prevent the clamping implant  109  from being entrained when the needle  104  is screwed back, it can be provided that the plunger  106  has a length such that the plunger  106  is at least insertable into the needle  104  to a position in which its distal end is at a distance from a distal end of the needle  104  that is less than 40%, 50% or 60% of the length of the clamping implant wire measured along the path of the wire. 
     The tip of the needle  104  is ground to a lancet point according to industry standards. 
     Due to the helical shape of the needle  104 , friction that builds up between the inner surface of the needle  104  and the plunger is a self-reinforcing process. Overcoming friction requires that additional axial forces are exerted onto the plunger  106 , which increases the contact pressure with which the plunger  106  rests against the wall of the lumen inside the needle  104 , which increase friction. 
     For reducing friction between the plunger  106  and the needle  104 , an initial fit of the plunger  106  inside the needle  104  with minimal stress is also advantageous. Since the force necessary to deflect the plunger  106  over a certain angle, depends on the 4 th  order of wire thickness, a minimal wire thickness of the plunger  106  is helpful for keeping initial normal forces low, in particular when the shapes of the needle  104  and of the plunger  106  do not correspond perfectly. 
     In unloaded condition, the plunger  106  has helical windings having a first diameter and the helix formed by the needle  104  has a second diameter. To keep friction due to the plunger  106  leaning against a wall surface of the lumen on the outside of the helical curve in response to axial pressure exerted onto the plunger  106 , the first diameter may be smaller than or equal to the second diameter. If a plunger having slightly smaller diameter than the needle  104  is used, the plunger  106  would fit inside the needle  104  with additional friction between the plunger  106  and the inside of the needle  104 . When it is attempted to push the plunger  106  through the needle  104 , friction will build up and therefore the radius of the helical shape of plunger  106  will expand. In turn, this will reduce normal forces between the plunger  106  and the needle  104  so that friction is reduced when the plunger  106  is pushed into the needle  104 . 
     At least the needle  104  lumen or the plunger  106  may be covered with a surface layer such that a frictional coefficient of the needle  104  lumen relative to the plunger  106  is smaller than a frictional coefficient between the main materials of the needle  104  and the plunger  106  (on opposite sides of the cover or covers), e.g. smaller than metal to metal if the needle  104  and the plunger  106  are both made of metal. 
     The plunger  106  may also be partially or completely be made of ceramic material, which is advantageous because of its low elasticity. Inadvertent deformation of the ceramic material of the plunger  106  that would lead to deformation can be prevented by encapsulation of the plunger  106  in the needle  104  and in the operating member(s). 
     The plunger  106  does not have to be of solid material over its entire length, but may also include a fluid column, preferably a liquid column between plugs sealed against the needle  104  lumen at its proximal and distal ends. An advantage of providing that pressing force for urging the clamping member out of the needle  104  is transferred by a fluid, at least over a portion of the plunger  106  length, is that normal forces between the plunger  106  and the inner surface of the needle  104  lumen on the outside of the helical curve, are not increased additionally as a result of expansion of the diameter of the helical shape of the plunger  106 . 
     For facilitating control over the needle  104 , the tool according to the present example further comprises a needle operating member  111  engaging a proximal portion of the needle  104 . In the present example, the needle operating member  111  is composed of a gripping member  112 , a shank  113  and a guide member  114 , which are fixedly mounted to each other, but shown separately in  FIG. 7 . 
     The needle operating member  111  is mounted to a plunger operating member  107 , such that, relative to the plunger operating member  107 , the needle operating member  111  is rotatable about a central longitudinal axis  108 , around which the helix formed by the needle  104  extends, and axially displaceable. Thus, the needle operating member  111  and the plunger operating member  107  are guided relative to each other for following screwing motion of the plunger  106  into and out of the needle  104 . For accurate guiding with little friction, the plunger operating member  107  and the needle operating member  111  have cylindrical outer and inner surface portions  115 ,  116  and  117 ,  118  with a sliding fit. 
     A helical channel  119  corresponding to the helix shape of the needle  104  is formed in the outer guide surface  116  of the shank  113  of the needle operating member  111 . This channel  119  forms a guide for the portion of the plunger  106  that projects from the proximal end  120  of the needle  104 , so that it can reliably be pushed into the needle  104  and buckling of the plunger  106  is avoided. The channel  119  also contains a portion of the needle  104  and keeps the needle  104  in alignment with the plunger  106 . On the outside, the channel  119  is closed off by the inner guide surface  115  of the plunger operating member  107 . Since neither the needle  104  nor the plunger  106  need to be shifted axially in another manner than with a screwing motion imposed by the helical shape of the needle  104 , the channel  119  for guiding the plunger  106  may also be provided in the inner surface of the plunger operating member  107  or in both the plunger operating member  107  and the needle operating member  111 . 
     At a needle anchoring position  121 , the needle  104  is anchored to the shank  113  of the needle operating member  111 . At a plunger anchoring position  122 , the plunger  106  is anchored to the plunger operating member  107 . If the needle operating member  111  is rotated in a left hand sense relative to the plunger operating member  107 , the plunger  106  is screwed into the needle  104  is screwed into the needle  104  from a position as shown in  FIG. 8  to a position as shown in  FIG. 9 . Although in the present example, the plunger operating member  107  is constituted by the outer member in which the needle operating member  111  is slidingly guided, it is also conceivable to fix the needle to the outer operating member and to fix the plunger  106  to the inner operating member. When applied to the example shown in  FIGS. 6-9 , this would result in a swap of the needle  104  and plunger  106  operating functions. 
     To avoid premature displacement of the clamping implant  109  relative to the needle  104  during insertion of the needle  104  into the tissue towards the deployment location, the plunger  106  is releasably lockable relative to the needle  104 . In the present example, this is achieved by providing the plunger operating member  107  with a locking pawl  123  at an end of a spring arm  124  that biases the locking pawl  123  into engagement with a locking recess  125 . As long as the locking pawl  123  is in engagement with the locking recess  125 , the needle operating member  111  is fixed relative to the plunger operating member  107 . After the locking pawl  123  has been disengaged from the locking recess  125  (e.g. by pressing down the biasing arm  124  with a finger or thumb), the needle operating member  111  can be rotated relative to the plunger operating member  107 , so the needle  104  can be screwed out of the tissue containing the deployment location while the plunger  106  is held essentially stationary, so that the clamping implant  109  is urged out of the needle  104 . 
     The tool is preferably packaged with the lock in locked condition. It may be provided that the tool also locks up when the plunger  106  is screwed into the needle  104  over a predetermined maximum distance, for instance the distance required for completely released pushing the clamping implant out of the needle. Furthermore, it can be provided that the second lock, once locked, can not be unlocked for preventing re-use of a tool designed for use as a disposable that is not suitable for cleaning and sterilization for re-use. In the present example, this is achieved by providing that the spring arm  124  is covered by the ring  112  of the needle operating member  111  when the plunger  106  is screwed into the over the predetermined maximum distance (see  FIG. 8 ). 
     For delivering a clamping implant for clamping a varicose vein, the needle may for instance have an inner diameter of at least 0.5 mm, at least 1.6 mm or at least 2 mm, and at most 2.8 mm, at most 3.2 mm or at most 5 mm. The diameter of the center line of the windings of the helix shaped needle may for instance be at least 10 mm, at least 12 mm or at least 14 mm and at most 25 mm, at most 30 mm or at most 40 mm. The diameter of the center line of the windings of the clip in unloaded condition may for instance be equal to the diameter of the center line of the windings of the helix shaped needle or up to 25% or 50% smaller. The length of the helical shape in longitudinal direction of its central longitudinal axis around which the helix formed by the needle  104  extends may for instance be at least 30 mm, at least 40 mm or at least 50 mm and at most 40 mm, at most 50 mm or at most 60 mm. The clamping implant  109  when inserted in the lumen of the needle  104  may for instance extend over at most 30% or 40% or 50% of the length of the needle  104 . The clamping implement  109  in unloaded condition may for instance extend over at least two or at least three full windings. The pitch between centerlines of successive windings of the needle  104  (in longitudinal direction of the central longitudinal axis of the helix), may for instance be at least 3 mm, at least 5 mm or at least 7 mm and at most 12 mm, at most 16 mm or at most 20 mm. The pitch between centerlines of successive windings of the clamping implant  109  in unloaded condition may for instance be less than 75% or less than 50% of the pitch between successive windings of the needle. The pitch between successive windings of the clamping implant  109  in unloaded condition may also be such that successive windings are in contact with each other, with or without a pre-stress biasing successive windings against each other. 
     Within the framework of the invention as set forth in the claims, many other variants of a tool and system are conceivable. For instance, instead of fitting in the needle ( 4 ,  104 ) completely, the clamping implant ( 9 ,  109 ) can fit inside the needle ( 4 ,  104 ) only partially, for instance because a distal tip forms a piercing point for piercing the helical trajectory through the skin and underlying tissue. The clamping implant ( 9 ,  109 ) can be arranged to contract on release, so that also an axial contraction of engaged tissue is achieved. The clamping implant ( 9 ,  109 ) can be applied to humans or animals. Instead of a single integral piece, the clamping implant ( 9 ,  109 ) can also consist of more than one part which may be temporarily or permanently connected to each other. 
     It is thus contemplated that other implementations of the invention may differ in detail from foregoing examples. As such, all references to the invention are intended to reference the particular example of the invention being discussed at that point in the description and are not intended to imply any limitation as to the scope of the invention more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the invention entirely unless otherwise indicated. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.