Abdominal closure method and device variations for closing ventral hernias and reducing recurrence

Abstract

To provide a combination of a magnetic and bioabsorbable device for ventral hernia closure and / or tension distribution for maintenance of tissue apposition for healing.SOLUTION: A combination of a magnetic and bioabsorbable device for ventral hernia closure and tension distribution for maintenance of tissue apposition for healing avoids long-term placement of foreign matter and precludes materials spanning the interior layer of the abdominal closure where risk to visceral structures exists.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to devices and methods for abdominal wall surgery. More particularly, the present invention relates to devices and methods for closing ventral hernias without element separation, high tension closure, or mesh reinforcement, and to devices and methods for distributing tension in surgical suture lines to aid healing, whether associated with or independent of hernia closure. [Background technology]

[0002] Four million open abdominal surgeries are performed in the United States (emedicine.medscape.com / article / 1961789-technique). A well-known postoperative complication is incisional hernia, which occurs due to failure of structural tissue healing and occurs in approximately 9-20% of patients after abdominal closure. Non-surgical ventral hernias also occur, but these represent a minority of cases. Another type of abdominal wall defect is the umbilical hernia.

[0003] Abdominal surgeons often face two related problems associated with closure of the abdominal wall (defined herein as the muscles and fascia of the anterior abdomen, whether or not they extend to the skin or peritoneum): (1) in the case of a pre-existing defect (hernia), optimizing the normalization of the retracted ventral hernia edges to their original tissue and function, and (2) avoiding fascial stripping and the development of primary or recurrent hernias, whether after normalization of the retracted edges or during primary closure after laparotomy.

[0004] One commercially available device that may potentially restore near-normal abdominal wall anatomy to retracted abdominal wall edges is the ABRA® Abdominal Closure System (Southmedic, Ontario, Canada). By applying gradual dynamic tension, the edges of abdominal wall defects can be retracted to near-normal tissue. However, because the ABRA® device is placed intra-abdominally, it poses a risk of injury to intra-abdominal viscera. Its trans-wound location interferes with intra-abdominal wound management. This is especially true for patients undergoing laparotomy, where the proportion of abdominal defects is low compared with patients with skin closure but underlying fascial defects. Additionally, the Trans Abdominal Strap (TAS Medical Inc., San Carlos, California, USA) uses a "zip tie"-type ratchet mechanism on a plastic strap to approximate the abdominal wall edges (Figure 1). While it has portions that transect both the superior and inferior abdominal wall closure sites, the inferior portion threatens the underlying viscera. Additionally, the Trans Abdominal Strap cannot be dynamically closed.

[0005] When attempting to prevent primary or recurrent hernias after abdominal wall closure, there are limited safe and effective methods for reinforcing the wound closure until it heals and gains tensile strength. Techniques generally fall into four categories: (1) suturing the wound, (2) reinforcing the closure with mesh, (3) filling the defect with mesh, and (4) reinforcing the abdominal wall layers with mesh. Various forms of sutures exist, such as filamentous mesh sutures and various rod-shaped sutures, that add surface area to the tissue interface and enhance anchoring strength.

[0006] Alternatively, surgeons may use large sutures to hold the abdominal wall in place during the early postoperative period, preventing dissection. However, these sutures may also tear tissue under high tension. Furthermore, by design, retaining sutures typically have portions that cross both the upper and lower abdominal wall closure sites. The portions closer to the abdominal wall may injure the underlying internal organs.

[0007] Mesh, a common denominator in many complex surgical approaches for abdominal wall closure, is a double-edged sword. Surgeons use mesh on various aspects of the abdominal wall to reinforce the closure site and prevent primary or recurrent hernia formation. While mesh is essential for current techniques, these common products are associated with significant short- and long-term complications, sometimes with devastating results.

[0008] The anchoring technique for mesh deployment poses additional risks: In commonly used methods, widely applied mattress sutures often trap and injure relatively large areas of tissue and critical structures, such as the motor nerves of the abdominal muscles, potentially resulting in abdominal wall paralysis and pain. Summary of the Invention [Problem to be solved by the invention]

[0009] Novel techniques and methodologies that can avoid mesh and other long-term or permanent implantable elements to normalize the edges of retracted ventral hernias and assist in tight abdominal closure following hernia reconstruction and high-risk primary closure are desirable. [Means for solving the problem]

[0010] The ideal approach to restore an abdominal hernia to its normal anatomy without the need for element separation, high-tension closure, or mesh reinforcement is as follows: a. Gradual, dynamic movement of tissues to their normal pre-pathological positions without loss of function. b. Avoid loops, straps, or other device elements that are large in the intraperitoneal segment and pose a risk to internal organs. c. Reduce the impact on patient activity during distraction by incorporating wearable elements. d. Make it easy to withdraw when the need arises or when things get complicated. e. In ideal circumstances, percutaneous elements should be avoided.

[0011] An embodiment is presented that meets the above criteria and allows for a device that uses magnetic distraction linked to bioresorbable tissue anchors to restore near-normal anatomical tissue structures. Once tissue margin apposition is achieved, the magnetic elements can be removed, leaving the bioresorbable elements to maintain tissue closure and optimize healing.

[0012] After restoring the anatomical position of the edges of a ventral hernia, whether at primary closure or after hernia reconstruction, elements can maintain apposition of the edges of the abdominal wall fascia during healing. a. Do not use bridging material deep within the abdominal wall (unlike retention sutures) to prevent device-related bowel or organ injury. b. Avoid permanent mesh and other materials that can cause complications many years after surgery. c. Avoid the use of absorbable mesh or other scaffolding materials that may result in a mechanically incompatible scar layer. d.Easy to deploy. e. Distribute tension over as many points and as wide an area as is practical and safe. f. Gradual transfer of force from the anchoring device to the healing scar.

[0013] One aspect of this embodiment, used after apposition of the tissue edges, includes bioabsorbable elements that maintain tissue closure and optimize healing. The bioabsorbable elements utilize mechanisms that form a connection between the posterior (inner abdominal wall) and anterior (outer abdominal wall) components. These mechanisms can include fixation mechanisms, such as threaded elements, ratcheting elements, and the like, used in combination with various fixation mechanisms, such as ratchets. Additionally, various mechanisms for clamping the wound site and attaching the components together are described. These mechanisms include ratcheting straps, ball chains, perforated strips, and the like.

[0014] In one variation of a tissue anchoring assembly, the assembly may generally include a first member having one or more first piercing elements extending from a first surface configured to contact a first tissue region, and a second member having one or more second piercing elements extending from a second surface configured to contact a second tissue region, the second member defining one or more openings corresponding to the locations of the one or more first piercing elements, and the first and second members configured to be secured relative to one another via the one or more first piercing elements.

[0015] In one method of approximating tissue, the method may generally include attaching a first tissue anchoring assembly to a first region of tissue, the first tissue anchoring assembly including a platform or base having one or more first piercing elements extending from a first surface. The method may further include attaching a second tissue anchoring assembly to a second region of tissue to approximate the first region of tissue, the second tissue anchoring assembly including a second platform or base having one or more second piercing elements extending from a second surface, and approximating the first region of tissue toward the second region of tissue by adjusting connecting elements secured to the first and second tissue anchoring assemblies.

[0016] Another variation of a tissue anchoring device may generally comprise a first member defining one or more anchoring members having a length extending from a surface of the first member, each of the one or more anchoring members having a distal penetrating end and having elements along at least a portion of its length, and a second member defining one or more openings into which the anchoring members are correspondingly received. The device may further include a third member defining one or more openings into which the anchoring members are correspondingly received, the third member configured to be fixed in position relative to the anchoring members and to maintain the position of the second member relative to the first member.

[0017] Yet another variation of the tissue fixation assembly may generally include a first member having one or more first piercing elements extending from a first surface configured to contact a first tissue region, and a second member configured to contact a second tissue region, the second member defining one or more openings corresponding to the locations of the one or more first piercing elements, the first and second members configured to be fixed relative to one another via the one or more first piercing elements, and may further include a magnetically attractive element attachable to at least one of the first and second members. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a cross-sectional view of a conventional device for approximating the edges of a ventral hernia. [Figure 2] FIG. 2 is a perspective view showing a pair of anchors with percutaneous members used to approximate the device after initial implantation. [Figure 3] FIG. 3 is a cross-sectional view showing a pair of abdominal wall anchors comprising a magnet or magnetic material implanted and connected under the skin (subcutaneously), an electromagnet outside the skin, and a biasing member connected to each other. [Figure 4]FIG. 4 is a perspective view showing a pair of abdominal wall anchors in which a subcutaneous magnet or magnetic substance and an external magnet are connected by a biasing member so as to pull the magnets inward. [Figure 5] FIG. 5 is an example showing the approximate vectors of the forces acting on the magnet and anchor of FIG. [Figure 6] 6 is a cross-sectional view showing an electromagnet in a housing with a biasing member, such as a spring, and a switch to provide feedback control of the position of the electromagnet. The electromagnet can be positioned to activate a first switch. [Figure 7] 7 is a cross-sectional view of an electromagnet within a housing with a biasing member and switch for feedback control of the position of the electromagnet, the electromagnet being positionable to actuate a second switch. [Figure 8] 8 is a cross-sectional view of an electromagnet within a housing with a biasing member and switch for feedback control of the position of the electromagnet, the electromagnet being positionable to activate a third switch. [Figure 9] Figure 9 shows the logic map for controlling the electromagnet based on the state of the switch. [Figure 10] FIG. 10 is a perspective view of an abdominal binder with tracks. [Figure 11] FIG. 11 is a perspective view of an anchor having, for example, four prongs and one or more tines. [Figure 12] FIG. 12 is a perspective view of an anchor having, for example, one prong, one or more barbs near the base of the prong, and one or more tines. [Figure 13] FIG. 13 is a perspective view of an anchor having first and second members having one or more prongs and one or more tines. [Figure 14] FIG. 14 is a perspective view of an anchor having first and second members, for example, having one prong and one or more tines. [Figure 15]FIG. 15 is a perspective view of an anchor having a first member and a second member that engages the first member, for example, via a ratchet element. [Figure 16] FIG. 16 is a perspective view of an anchor having a first member, a second member, and a third member that restricts movement of the second member relative to the first member. [Figure 17] FIG. 17 is a side view of an anchor having a first member, a second member, and a third member that restricts movement of the second member relative to the first member. [Figure 18] FIG. 18 is a side cross-sectional view showing the second and third members, with surfaces configured to limit the ability of the button fingers to bend toward the backplate. [Figure 19] FIG. 19 is a perspective view showing an anchor with first and second members having a third member configured as a removable pin that limits relative movement of the second plate with respect to the first plate when the pins are engaged. [Figure 20] FIG. 20 is an exploded perspective view showing an anchor having first and second members with a third member configured as a removable pin. [Figure 21] 21 is a side cross-sectional view of an anchor including first and second members and a third member configured as a removable pin that limits relative movement of the second plate with respect to the first plate when the pins are engaged, and the second plate limits movement of the third member away from the first member. [Figure 22] FIG. 22 is a perspective view of an anchor having first and second members and a third member configured as two pin segments connected by a flexible element, the third member limiting movement of the second plate relative to the first plate when the pins are engaged. [Figure 23]FIG. 23 is a side view of an anchor having first and second members and a third member configured as two pin segments connected by a flexible element, the third member limiting movement of the second plate relative to the first plate when the pins are engaged. [Figure 24] FIG. 24 is a top view of an anchor having first and second members and a third member configured as two pin segments connected by a flexible element, the third member limiting movement of the second plate relative to the first plate when the pins are engaged. [Figure 25] FIG. 25 is an exploded perspective view of an anchor having first and second members and a third member configured as two pin segments connected by a flexible element. [Figure 26] FIG. 26 is a side cross-sectional view of an anchor having first and second members and a third member configured as two pin segments connected by a flexible element, the third member limiting movement of the second plate relative to the first plate when the pins are engaged. [Figure 27] FIG. 27 is a perspective view of a three-piece anchor, with the third piece configured as a nut engageable with the threads of the prongs. [Figure 28] FIG. 28 is a perspective view of an anchor having three members, the third member being configured as a nut that can be engaged with the threads of the prong, and the second member including a ratchet element that further engages the third member in place on the prong. [Figure 29] FIG. 29 is a perspective view of an anchor having three members, the third member being a nut that threads onto the threads of the prong, and the third member also comprising a flexible spring member. [Figure 30] FIG. 30 is a side cross-sectional view of a three-member anchor, the third member being a nut that threads onto the threads of the prong, and the third member also comprising a flexible spring member. [Figure 31]FIG. 31 shows multiple anchors arranged in adjacent pairs, each connected to the other by a suture through holes in the device, to approximate two opposing tissue edges. [Figure 32] FIG. 32 is a perspective view showing a pair of devices connected by a flexible member having a plurality of pre-set locking portions, such as a ball chain. [Figure 33] FIG. 33 is a perspective view showing multiple sets of devices like those of FIG. 32 implanted within the abdominal wall. [Figure 34] FIG. 34 is a perspective view showing a pair of devices connected by a flexible member having a plurality of pre-set fastening portions, such as a ball chain, according to another example. [Figure 35] FIG. 35 is a perspective view showing a device having one or more prongs from a first member inserted into corresponding openings in a second member. [Figure 36] FIG. 36 is a perspective view of the device with the prongs shortened and reconfigured or deformed, such as by melting, to retain the second member. [Figure 37] FIG. 37 shows the device of FIG. 35 with the prongs cut off. DETAILED DESCRIPTION OF THE INVENTION

[0019] One method for closing abdominal hernia defects involves using soft tissue anchors 202, 220 (described in more detail below) with a flexible connecting member 230 extending percutaneously from each anchor, with the goal of restoring abdominal anatomy to a normal or near-normal state. The anchors 202, 220 are secured to the underlying abdominal wall, and the connecting member 230 can extend percutaneously from the implanted anchors 202, 220 through tissue to the exterior of the patient's skin. The percutaneous connecting member 230 can be a suture or other structure that can be periodically unwound or otherwise applied to apply a force to bring the anchors closer together (FIG. 2). The terminal or looped portions of the connecting members can be coupled together via a biasing member 240, with the biasing member 240 and the distal portion of each opposing connecting member 230 remaining outside the patient. This can involve pulling the percutaneous connecting members 230 together with the biasing member 240, such as a spring, elastic band, or mechanical system, to apply a biasing force. Typically, the force applied by biasing member 240 will be in the range of, for example, 1 Newton to 8 Newtons, and preferably, the force is kept below, for example, 4 Newtons. Connection members 230 can be configured to be long enough to penetrate from the anchors through the skin surface, although this length will depend greatly on the specific anatomy of each individual patient. Biasing members 240 in their extended state should be long enough to accommodate the distance between connecting members 230, which in most patients should be less than 30 cm, for example. Once the abdominal wall edge is sufficiently close, less than 3 cm, and ideally less than 1 cm, biasing member 240 and percutaneous connecting member 230 may be removed, and anchors 202, 220 may be directly connected to one another subcutaneously, such as with sutures.

[0020] Alternatively, the magnetic plate or element 270 may be integral with or directly attached to the intervening connecting segment 230 to a soft tissue anchor secured to the underlying abdominal wall. Rigid or semi-rigid attachment between the connecting segment 230 and the element 270 may be achieved by insert molding, adhesives, or other methods, such as heat staking, ultrasonic welding, press-fitting, or snapping. Alternatively, a more compliant attachment may be achieved by attaching sutures or other flexible members to the soft tissue anchor and magnetic element. Preferably, the magnetic element 270 is positioned so that it is located at the superficial layer of subcutaneous fatty tissue 302 and just beneath the skin 300 ( FIG. 3 ). This attachment method allows the magnetic piece to be positioned at the desired layer of tissue while remaining subcutaneous by adjusting the distance between the magnetic member and the soft tissue anchor. In this manner, the magnetic element 270, anchor, and connecting segment 230 can remain subcutaneously positioned within the patient's body. One or more of the magnetic elements may be constructed of a ferrous or magnetically charged material (e.g., steel plate).

[0021] In another variation, the one or more magnetic elements may be one or more permanent magnets. Alternatively, the one or more magnetic elements may be composed of one or more electromagnets. However, this requires the application of current through the skin (wirelessly or via a percutaneous wire), further complicating the system. To improve the biocompatibility of the device or to prevent corrosion of the magnets, the one or more magnetic elements may be encapsulated in another material, such as plastic. Alternatively, the attachment may consist of a suture or wire threaded through a hole or other way through the abdominal wall around all or part of the posterior portion of the soft tissue anchor, through a hole or other way around all or part of the anterior component of the soft tissue anchor, and then connected to the magnetic element.

[0022] External magnets 260 (FIG. 3) corresponding to the implanted magnetic elements 270 can be positioned outside the body and attract the magnetic elements 270 subcutaneously in the abdominal area. These external magnets 260 may include a biasing mechanism 240 that pulls the units on opposite sides of the wound, incision, or hernia toward each other, thereby drawing the subcutaneous magnetic elements 270 toward each other and ultimately drawing the abdominal wall edges on either side of the trauma defect toward each other. The external magnets 260 can exert a force ranging from 1 N to 8 N, for example. The external magnets 260 can be permanent magnets or electromagnets, and in the case of electromagnets, the force between the external magnets 260 and the internal magnet 270 can be limited, controlled, and / or cycled. Specifically, to avoid the risk of tissue necrosis, the pressure exerted on the tissue between the external magnets 260 and the internal magnet 270 can be maintained at, for example, 32 mmHg (0.619 psi, 4.27 kPa) or less. Pressures above this level can impair blood perfusion to the tissue, and if maintained for an extended period of time, can lead to tissue necrosis and failure. Alternatively, the force exerted by the external magnet 260 can be varied to cause the pressure on the tissue to exceed 32 mmHg (0.619 psi, 4.27 kPa) for some periods and then drop to levels below 32 mmHg (0.619 psi, 4.27 kPa) for other periods, allowing sufficient intermittent perfusion to maintain tissue health.

[0023] The mechanism (FIG. 4) that attracts the external magnets 260 toward each other (thereby moving the subcutaneous magnetic material 270 toward each other, thereby bringing the abdominal wall edges closer together) may be composed of a biasing member 240 that applies a known force, an electromechanical drive device capable of applying a known force, or other mechanisms capable of moving the external magnets toward each other. In the case of an elastic member (FIG. 4), the system may include an elastic band, a constant force spring, a torsion spring, a coil spring, or the like. The electromechanical system may include a motor, such as a servo motor, a stepper motor, or a linear actuator, directly or indirectly coupled to the magnet. Forces may also be generated by pneumatic, hydraulic, or combustion systems. Mechanisms such as a rack and pinion can be used to convert rotary motion into linear motion. A mechanism consisting of multiple gears is envisioned to achieve the desired movement. Alternatively, a cable or pulley system may be used to move the external magnets. Various other mechanisms are also contemplated.

[0024] When using magnets (here, subcutaneous and external), the magnetic attraction (or repulsion) between two magnets varies with the distance between them. The rate at which the force changes depends on the distance and shape of the magnets, but at intermediate distances it generally varies proportionally to the inverse square of the distance (a magnet twice as far away will pull with 1 / 4 the force). For example, a magnet large enough to exert a certain force through 10 mm of tissue will exert four times as much force through only 5 mm of tissue. This force ratio is the same whether two magnets or one magnet and one component can be used to induce temporary magnetism.

[0025] The device's internal magnet 270 can be placed on the fascia of the abdominal wall 304 (leaving subcutaneous fat and skin between the magnet and the plate) or on the surface of the subcutaneous fat 302, leaving only a relatively thin layer of skin 300 between the plate and the magnet (FIG. 3). In either case, varying tissue thickness can significantly affect the amount of force (pressure) the magnet exerts on the tissue, especially if the subcutaneous fat increases the distance between the plate 270 and the magnet 260. For example, if the magnet is sized to exert a pressure of less than 4.27 kPa on 10 mm of tissue, but the actual tissue is only 5 mm thick, the pressure could rise to 8.54 kPa, potentially resulting in severe necrosis. For these reasons, the internal magnetic element 270 can be placed under the skin in one variation, but preferably not under the subcutaneous fat.

[0026] When the abdominal wall edges are brought together, the force applied to the tissue may be less than 400 g, and in some cases less than 300 g (2.94 N) per pull. Because the external magnet 260 is in a different plane than the abdominal wall, it tends to pull the inner elements at an angle, creating a force vector (FIG. 5). For example, to impart a medial pull of 2.94 N inward, the external magnets 260 may pull on each other with a similar force. In the example of the 45-degree angle of the connecting member 230 in FIG. 5, A and B are both equal to an equal force of 2.94 N applied to the outer surfaces. This creates a vector between the external magnet 260 and the internal magnet 270: C = 2.94 N * √2 = 4.15 N. To distribute this 4.15 N force across the tissue and maintain a pressure below 4.27 kPa requires an area greater than 9.75 cm², which is the area of a circle greater than 3.5 cm in diameter. Alternatively, a smaller diameter circle can be formed while still protecting the tissue with an intermittent magnetic force, as described below. While this example is limited to one particular variation, other configurations can be used to achieve similar results.

[0027] To limit the force (pressure) applied to the tissue, at least a portion of the magnetic force may be provided by an electromagnet. When one or more electromagnets are used, the force can be controlled by turning the electromagnet off, limiting the current in the electromagnet's wire, rapidly cycling the electromagnet on and off (using switching techniques such as pulse-width modulation), or reversing the polarity of the electromagnet (creating a repulsive force between it and other electromagnets or permanent magnets). In all cases, controlling the magnetic force requires measuring or limiting the force. Alternatively, if well-characterized magnets are used, the distance between the magnets can be determined by knowing the magnetic field strength at a reference point in the system. Therefore, the following control methods are possible:

[0028] If one wishes to measure the strength of a magnetic field, a sensor such as a fluxgate capable of measuring magnetic field strength can be placed between two magnets (or between a magnet and an induced magnetic material). By knowing the magnetic level of the magnets, the magnetic field strength at a point between the two magnets can be used to determine the distance between the magnets. This method relies on knowing the magnetic strength of both magnets, sufficient sensor calibration, and limiting external magnetic fields (interference). The magnetic field strength at the sensor's location can then be used to adjust the power supplied to the electromagnet, limiting the magnetic force and thereby controlling the pressure applied to the tissue between the magnets.

[0029] Another method for controlling the pressure applied to the tissue between the magnetic elements is to directly measure the force acting on one of the elements (using a sensor such as a load cell) or the distance (with a known rate of deflection) of an elastic member such as a spring. This distance can then be converted to force, and the force can be controlled by varying the power to the electromagnet. Various mechanisms for measuring distance include known displacement measurement methods, such as linear potentiometers, rotary potentiometers (with a mechanism for converting linear displacement to rotation), linear encoders (e.g., glass scales), rotary encoders (with a mechanism for converting linear displacement to rotation), optical displacement measurement (laser, diffraction, or imaging), capacitive sensors, magnetic sensors, inductive sensors, and eddy current sensors. Another method for controlling the force (i.e., pressure) applied to the skin between two magnets is to use one or more switches 252, 254, and 256 that activate when a specific force is applied to the magnet, thereby displacing the magnet 260, which acts against a biasing member 262 (e.g., a spring) with a known spring constant. The switch can turn off the electromagnet until the force falls below a safe level. Using multiple switches (e.g., two or more) can achieve a gradual effect, with one switch reducing the electromagnetic force and a second switch turning off the electromagnet. Electronic circuitry can be used for signal processing. For example, slowing the response time of the electromagnet's current can limit spurious switching of the electromagnet due to patient movement or other vibrations that cause a momentary increase in force but whose duration is insufficient to cause necrosis or other undesirable effects. Alternatively, the switches or switch logic can be reversed, so that one or more switches increase the current through the electromagnet when displacement is insufficient. Any number of different switch types can be used, including optical switches, mechanical switches, various electrical contacts, and photoresistor / diode pairs.

[0030] 6, 7, and 8 are cross-sectional views showing electromagnet 260 held within housing 250. Electromagnet 260 may be slidably held within housing 250, but away from the bottom of housing 250 and from internal magnet 270, by, for example, a spring 262 or other biasing mechanism of known rate (force). When the attractive force between electromagnet 260 and internal magnet 270 is sufficient to cause electromagnet 260 to change the state of the switch (e.g., turn "on"), electromagnet 260 can be turned off until the switch is turned "off." Additional switches, such as switches 252, 254, and 256, can be used in combination with multiple individual windings on the same electromagnet core (or separate cores) to incrementally adjust the force of electromagnet 260 by turning on one or more windings at a time. Alternatively, multiple switches 252, 254, 256 may be utilized in combination with a method for limiting the current or voltage through the windings of the electromagnet, thereby limiting the electromagnetic force depending on the position of the electromagnet within the housing.

[0031] FIG. 9 shows an example decision tree (logic) that can be used to detect and control the position of an electromagnet using three switches. In this embodiment, the control system begins with logic 900 and continuously or periodically monitors the states of switches 252, 254, and 256. If the control system detects that an electromagnet has activated the first switch 252 (step 910), it increases the voltage to the electromagnet, thereby increasing electromagnetic force 920. If the control system does not detect that an electromagnet has activated the first switch 252 (step 910), it then checks the state of the second switch 254 (step 912). If the control system detects that an electromagnet has activated the second switch 254 (step 912), it applies a constant voltage to the electromagnet to maintain a constant electromagnetic force 922. If the control system does not detect that an electromagnet has activated the second switch 254 (step 912), it then checks the state of the third switch 256 (step 914). If an electromagnet is detected to have actuated the third switch 256 (step 914), the system reduces the voltage to the electromagnet to maintain the reduced electromagnetic force (step 924). After adjusting the electromagnetic force in steps 920, 922, and 924, the logic loops to repeatedly interrogate the multiple switches. If an electromagnet is not detected to have actuated any of the switches 252, 254, and 256 (steps 910, 912, and 914), the logic stops and an error message is displayed to the user (step 902).

[0032] In another version, the external magnetic pieces are held to the skin by a binder 310. The binder 310 may be constructed of a flexible fabric, such as cloth, allowing the binder 310 to be wrapped around the patient's body. The binder 310 may include a biasing element for applying gentle and dynamic pressure. As shown in the perspective view of FIG. 10, in one variation, the binder 310 may be provided with slits, grooves, or tracks 312 so that the tracks 312 are aligned parallel to one another across the width of the binder 310. These tracks 312 are positioned over the patient's body so that the tracks 312 extend across the abdominal wall defect, providing channels in which the magnetic elements 270 are slidably retained, helping to maintain the orientation and positioning of the elements relative to one another. Such an arrangement may also be used to prevent unintentional decoupling of the external and internal magnetic pieces. This is especially true in the case of an ambulatory patient, where everyday movement can cause accelerations on the external magnet that can counteract the magnetic attraction to the internal magnet and cause the external magnet to become dislodged from the patient. Additionally, the track can serve the additional purpose of further limiting movement of the device pair along the abdominal wall defect relative to other device pairs positioned elsewhere.

[0033] Additionally, various magnetic shielding covers can be placed over dynamic systems to shield them from unwanted external magnetic fields. Materials can include metals (or alloys of these) such as iron, steel, nickel, cobalt, and other ferromagnetic materials. More exotic materials can be specifically formulated for magnetic shielding, such as MuMetal® (Milspec 14411C, Magnetic Shield Corp., Bensenville, Illinois).

[0034] It also includes tools to facilitate passage of the internal magnet through an open wound to the desired location, or from outside the skin to the desired location under the skin.

[0035] The electronic systems described above may incorporate Wi-Fi, Bluetooth® (Bluetooth Sig, Inc., Kirkland, WA), or other provisions for connecting to networks or external computing devices to enable tracking and control of forces, tissue movement, and / or other metrics via applications (apps), internet connectivity, remote monitoring, or integration into the Internet of Things (IoT), etc. This allows for control and / or monitoring by the patient, a healthcare worker, a medical professional, and / or automated algorithms (including "artificial intelligence").

[0036] Tissue anchors are described that can be attached to (or near) the edges of the abdominal wall soft tissue to allow for the application of distributed tension to the soft tissue once the edges of the abdominal wall defect have been brought together via the devices and methods described herein, or separately upon completion of the primary abdominal procedure. The devices and methods described herein can be used in combination with any of the devices and methods in which they are incorporated, and the described elements can be used in any combination with the devices and methods described herein.

[0037] The described soft tissue anchor embodiments may be formed from partially or entirely bioabsorbable materials, including, but not limited to, polylactic acid (PLA), polyglycolic acid (PGA), polylactic / glycolic acid (PLGA), polydioxanone (PDO, PDS), trimethylene carbonate (TMC), polycaprolactone (PCL), and various copolymers of these materials, such as PLA-co-TMC and PLGA-co-PDO.

[0038] Alternatively, the device may be partially or entirely made of non-bioabsorbable materials, such as stainless steel, titanium, polyethylene (PE), polypropylene (PP), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), or other materials that do not significantly degrade in the body.

[0039] In various embodiments, antibiotics, active pharmaceutical agents, and / or antimicrobial agents may be incorporated as a surface coating or into the material.

[0040] The prongs and tines, described below, come in a variety of shapes, including, but not limited to, cylindrical, elliptical, rectangular, conical, and parabolic shapes, and the tips of the prongs and tines can take multiple forms, including cutting, atraumatic, invasive, multi-bevel, and "pencil" tips.

[0041] The portion of the anchor that passes through the fascia and muscle of the abdominal wall can be angled or hinged relative to the base or platform so that the forces in the middle of the suture are more parallel to the anchor element, reducing the anterior moment arm that tends to apply all or most of the force at the anterior rectus sheath rather than through the entire thickness of the abdominal wall (anterior rectus sheath, rectus muscle, and posterior rectus sheath, if present).

[0042] In one embodiment (perspective view in FIG. 11 ), a base or platform anchor 100 has one or more prongs 102 intended to penetrate the anterior rectus sheath (fascia), where tensile strength is highest, and / or tines 104 intended to penetrate only the posterior rectus sheath (fascia), if present. The anchor 100 is comprised of a base that defines one or more openings, and the prongs 102 that project from the base in a normal direction or at an angle relative to the plane formed by the base. The prongs 102 may also define a first diameter or thickness, e.g., 1-6 mm, and may form any number of cross-sectional shapes, as described above herein. Additionally, the prongs 102 may extend a distance of, e.g., 7-25 mm, to help ensure that the prongs 102 penetrate the entire thickness of the abdominal wall to which the anchor 100 is secured (although a longer length may be required if the abdominal wall is abnormally thick). The excess length may be trimmed off, as described in more detail herein.

[0043] The prongs 102 can also be positioned on the base for secure fixation to the tissue. While four prongs 102 are shown extending parallel from each corner of the base, other variations include more or fewer prongs 102 positioned at different locations on the base.

[0044] The tines 104 may also be incorporated to extend from the base, each defining a second diameter or thickness (e.g., 1-6 mm), and may form any number of cross-sectional shapes as described herein above. Additionally, the tines 104 may extend a relatively shorter distance (e.g., 1-8 mm) than the prongs 102 to more securely engage the tissue, but may not extend across the entire width of the tissue. Furthermore, the tines 104 may be positioned on the base and between the prongs, as shown.

[0045] Alternatively, the anchor may be comprised of a base or platform with prongs and at least two elements (prong holes) that pass through the abdominal wall to allow for the passage of a suture loop. The holes may be parallel (nearly horizontal or axial) to the nerves to prevent critical neural structures from becoming caught within the suture loop. The suture anchor is inserted from the inside of the abdominal wall, with the prongs penetrating the abdominal wall partially or completely. Sutures are then threaded through one or more holes to connect the suture anchors on either side of the incision, thereby holding the abdominal wall edges together during healing. Alternatively, the components may be reversed, with the base or platform inserted from the outside and the prongs threaded through the wall. The suture is then passed from one prong through the wall to a second prong on the same side of the incision. Other bridging embodiments are also applicable here. In yet another example, the anchor may be comprised of a base or platform with prongs. The prongs may have one or more barbs along their length. The base or platform is inserted from the outside of the abdominal wall with the prongs extending into the abdominal wall without penetrating it. One or more barbs serve to hold the anchor in place in the abdominal wall. Holes or other features are provided on the base or platform for attaching sutures. Sutures are then threaded through one or more holes to connect the anchor to a complementary anchor on the opposite side of the incision, holding the abdominal wall edges together during healing.

[0046] Alternatively (as shown in the perspective view of FIG. 12), the base may be circular (or any number of other shapes, such as elliptical, oval, etc.) with a single prong 202 extending perpendicularly or at an angle from the base. The prong 202 similarly extends a distance of, for example, 1-25 mm (although a longer length may be required if the abdominal wall is unusually thick) from a base that may be, for example, 1-6 mm in diameter. Also, the prong 202 may be circular (or any other cross-sectional shape described herein), and although shown extending from the center of the base, the prong 202 may be located at other locations on the base. Additionally, the ends of the prongs 202 may be formed with a piercing tip, preferably of a non-invasive shape, to facilitate insertion of the prongs 202 into tissue during engagement (the piercing tip may be removed after tissue fixation, as described herein), and the distal portions of the prongs 202 may be configured to exhibit threads, notches, or other non-smooth outer surfaces to facilitate engagement and fixation with corresponding members, as further described herein.

[0047] Apart from the prongs 202, the anchor 200 may further include one or more tines 204, which may extend from the base a distance of, for example, 1 to 8 mm and with a diameter of, for example, 1 to 6 mm. The tines 204 may extend from the base at any or uniform positions, for example, from a circumferential position, and although three tines 204 are shown, a fewer or greater number of tines 204 may be used to further secure the anchor to tissue. Optionally, the prongs 202 or tines 204 may have notches, barbs, or undercuts 206 formed along their outer surfaces, which help secure the anchor to tissue and reduce the likelihood of dislodgement.

[0048] To protect internal organs, anchors are typically placed with the prongs threaded from the inside of the abdomen to the outside. This safety measure does not limit the use of anchors; prongs can also be threaded from the outside of the abdomen to the inside.

[0049] Anchors similar to the previous embodiments are ideally coupled to a second member 110,410 having a base or platform (as shown in the perspective views of FIGS. 13 and 14), preferably coupled to the superficial layer of the anterior rectus sheath (fascia). In such embodiments, the anchor 100,400 comprises a base (first member) with one or more prongs 102,402 positioned from the interior to the exterior of the abdominal wall, the prongs 102,402 extending through the thickness of the wall, and a base or platform (second member) 110,410 on the exterior of the wall, clipped, snapped, or otherwise attached to the prongs from the first member. The variation shown in FIG. 13 illustrates an embodiment in which the second member comprises a base defining one or more openings and one or more tines 112,412 extending from the base of the second member in a manner similar to tines 104,404. The second member may further define openings or receiving channels corresponding to the positions of the prongs 102, 402 extending from the first member. In this manner, the second member may be positioned such that the prongs 102, 402 extend from the first member through corresponding openings formed in the second member, and the first and second members may maintain a parallel orientation while sandwiching the tissue thickness between them. One or more tines 112, 412 of the second member may be oriented toward the first member, as shown, to further secure the tissue thickness between the members.

[0050] A lock or shoulder 116 may also be positioned to extend from the surface of the second member, such that the shoulder 116 extends in a direction opposite the tines 112. The shoulder 116 may be positioned along or adjacent to the edge of the second member between the openings, such that the shoulder 116 is positioned along the edge closest to the second, opposing anchor member for attachment of one or more sutures or other bridging elements, such as a ball chain. This suture or chain can attach a similar provision to a second anchor on the opposite side of the incision to hold the abdominal wall edge during healing. Optionally, in addition to one or more prongs, the first and / or second members may be positioned with short tines 104, 112 configured to pass through only a portion of the abdominal wall. The tines 104 on the first member may pierce the posterior rectus sheath, if present. The tines 112 on the second member may pierce the anterior rectus sheath. Such tines 104, 112 can be made less likely to come off by providing them with notches, barbs, undercuts, etc.

[0051] 14 shows a second member 410 that can also engage with prongs 402 from the first member, but that can form an opening sized to receive the prongs 402 through a central opening. The second member can further have one or more fixation members 414 extending therefrom that form one or more openings for engaging a second anchoring device via a connector, such as a suture, during tissue approximation. The fixation members 414 can extend planarly or at an angle to form any number of openings (e.g., one, two, three, or more openings), and one or more tines 412 can extend transverse to the openings to engage tissue.

[0052] Various tools can be used to measure the force applied to the tissue clamped between the first and second members and limit the pressure to a desired level (e.g., less than 32 mmHg (approximately 4.26632 kPa)) to prevent tissue necrosis or damage.

[0053] In one embodiment (FIG. 15), the anchor comprises a first member 500 (also called a posterior plate or base) having one or more prongs 502 extending perpendicularly from the plate as described above, the prongs 502 being positioned from the inside to the outside of the abdominal wall, with the prongs 502 extending through the thickness of the abdominal wall, and a second member 510 (also called an anterior plate or base) on the outside of the abdominal wall. The second member 510 has integrally formed elements such as flexible fingers 518 that engage notches 508, 509 or similar features on the prongs 502 from the plate. The flexible fingers 518 may be configured as cantilevered members that are biased against and contact the surface of the prongs, allowing the second member 510 to slide the prongs 502 toward the first member, but when the member is biased in the opposite direction, the fingers 518 engage the notches 508, resisting movement away from the prongs (off the plate). Alternatively, the flexible fingers 518 on the second member 510 may be replaced with additional parts, such as tabs, that allow similar downward movement of the prongs 502 and resist upward movement of the prongs 502. The fingers 518 or tabs may be located on one or more sides of the prongs 502. FIG. 15 shows flexible fingers 518 acting on two sides of the prongs. Specifically, the posterior plate 500 has one or more prongs 502, with all or a portion of each prong 502 being provided with ridges or rings. The second member 510 includes a hole configured to slide over the prong 502 .

[0054] In each of the described embodiments, the first member may be alternatively referred to as a posterior plate or base due to its relative position within the body, and the second member may be alternatively referred to as an anterior plate or base due to its relative position within the body and relative to the posterior plate or base.

[0055] 16 and 17, the anchor includes a first member 200 having one or more prongs 202 positioned from the interior of the abdominal wall, the one or more prongs extending through the thickness of the abdominal wall, and a second member 210 that can engage with the prongs 202 such that the second member 210 is positioned on the exterior of the abdominal wall. Whether or not the second member 210 is secured to the prongs 202, the second member 210 may be further restricted from movement relative to the first member 200 by a third member 220. The third member 220 functions as a retainer and can take various forms, such as a clip, snap, screw, or attached to the prongs 202 from the first member. The third member 220, shown in this example as a ratchet button, is configured to match the size or diameter of the first member 200, but may further include one or more cantilevered fingers 222 configured to extend radially within an opening into which the prong 202 is inserted so as to slide over ridges on the outer surface of the prong 202. As the fingers 222 slide over the ridges, the fingers may bend away from the second member 210. The third member 220 may be advanced under the prong 202 until it contacts the second member 210 (which may compress tissue between the first and second members). Alternatively, the third member 220 and the second member 210 may be pre-assembled before being advanced under the prong 202.

[0056] In some embodiments (as shown in the side cross-sectional view of FIG. 18 ), the shape of the contact surfaces of the second member 210 and the third member 220 is configured to prevent or limit the ability of the fingers 222 of the third member 220 to bend toward the second member 210. When pressure is applied to the second member 210, the second member 210 tends to move away from the first member 200, and when the third member 220 is pressed, the fingers 222 tend to bend toward the first member 200 and expand to a larger effective diameter than the ridges of the prongs 202. However, because the second member 210 limits the bending of the fingers 222 in that direction, the force that the ratchet can withstand is much greater than that of an unsupported ratchet. The third member 220 and second member 210 can be pre-assembled or manufactured so that a user can apply them together to the first member 200, although the mating surface between the flexible fingers 222 and the second member 210 still limits the ability of the flexible fingers 222 to bend toward the first member 200.

[0057] In yet another example (as shown in the perspective view of FIG. 19 and in FIGS. 20 and 21), a first member 600 has one or more prongs 602 and one or more holes, openings, or channels 603 formed through the prongs 602 perpendicular to the primary axes of the prongs 602. A second member 610 has holes configured to slide over the prongs 602. A third member is comprised of one or more pins 680, which are removable and sized for insertion into the channels 603 formed through the prongs 602. The pins 680 may be simple cylinders or may have additional features such as springs connecting two or more pins 680 (for insertion into holes in multiple prongs at once), heads for ease of handling, or a "T" shape to facilitate handling while preventing the pins 680 from passing completely through the prongs 602. This design can be further refined by providing the second member 610 with features such as circumferentially extending ribs 617. By over-compressing the "sandwich" of second member 610, tissue, and first member 600, pin 680 can be inserted into channel 603 of prong 602, and once the sandwich is released, ridges 617 on second member 610 can prevent pin 680 from sliding out of the opening and act as a stop for release of pin 680. Alternatively, it can consist of a ring that enters channel 603 on one or both sides.

[0058] In yet another example (as shown in the perspective view of FIG. 22 and in FIGS. 23-26), a first member 700 includes a plurality of prongs 702 with one or more holes, openings, or channels 703 formed therethrough perpendicular to the primary axes of the prongs 702. Note that while two prongs 702 are shown in this embodiment, alternative examples may incorporate more than two prongs 702. In either case, the prongs 702 may be positioned to extend parallel to one another to facilitate engagement with the second member 710. Furthermore, while the prongs 702 are shown extending perpendicular to the first member 700, the prongs 702 may each extend parallel to the first member 700 at an angle, if desired. The second member 710 includes a plurality of holes configured to correspondingly slide over the prongs 702. The third member 780 may be comprised of one or more pins, the proximal ends of which are connected to one another via connecting members that may form a curved or arcuate configuration. In this manner, a curved connecting member may be coupled to a corresponding pin at each terminal end. The pins are removable and sized for insertion into channels 703 formed through the prongs 702. In this manner, the pins are inserted into corresponding openings along each prong 702, with the curved connecting members providing a spring-like bias that urges each pin to remain in its corresponding opening and prevents accidental disengagement of the pins from the prongs 702. To release the pins to adjust the second member 710, the pins are urged toward one another against the biasing force provided by the curved connecting members; to re-engage the pins with the holes, the pins are simply released so that the connecting members move them apart, allowing the pins to fit into the corresponding holes. The pins 780 may be simple cylinders, or may have additional features such as springs connecting two or more pins 780 (to insert into multiple prong holes at once), heads for ease of handling, or a "T" shape to facilitate handling while preventing the pins 780 from passing completely through the prongs 702.

[0059] 27 and 28, a threaded second member 810 can be threaded onto threaded prongs 805 from the first member 800. However, if the second member 810 is threaded onto the prongs 805, it is not feasible to provide small second tines on the second member 810 and / or first member 800 because the tines cannot rotate within the tissue. Therefore, the screw attachment mechanism can be a three-piece design in which a threaded third member 890 limits the relative movement of the second member 810 with respect to the first member 800.

[0060] Alternatively, the third member 890 may comprise a nut that threads onto the prong 802 from the first member 800. Preferably, the mechanism utilizes a threaded element 805 in combination with a ratchet to secure the third member to the prong, providing both the clamping force and the locking mechanism for the device when assembled. The first member 800 and second member 810 of the device are inserted into the abdominal wall similar to previous constructs. The threaded ratchet 890 mates with the posterior prong 802, compressing the threaded ratchet against the second member 810. The second member 810 also includes mating ratchet teeth 819 that interact with opposing features 892 on the threaded ratchet. Once a certain amount of pressure is applied to the abdominal wall tissue between the first and second device plates, the ratchet does not disengage, thereby preventing the button from disengaging from the prong.

[0061] Alternatively (as shown in the perspective view of FIG. 28), the second member 810 has fingers 818 or other elements that act as a ratchet on the threads 805 of the prongs, allowing the second member 810 to be positioned (axially) on the prongs and held in place while the third member 890 is threaded onto the prongs.

[0062] In yet another embodiment (as shown in the perspective view of FIG. 29 and the cross-sectional view of FIG. 30), the third member 820 may incorporate flexible elements 824 integrally formed with its structure. These flexible elements 824 may extend radially inward between selected locations around the circumference of the member 820 and connect to a central ring member that may be coupled to the prongs 802. The flexible elements 824 may form one or more curved members that allow the central ring member to flex relative to the outer ring members that form the circumference of the third member 820 via the flexible elements 824, thereby allowing the flexible elements 824 to function as a pressure relief spring, allowing the second member to float as needed under higher pressures after device implantation. This function may be useful if the abdominal wall expands due to muscle contraction or edema, increasing the compressive forces between the device plates.

[0063] In embodiments in which any of the anchors and sutures described above are bioabsorbable, each of these components can be bioabsorbed by the patient's body, leaving no permanent traces of foreign material that could later cause complications such as infection. As shown in the perspective assembly view of FIG. 31, one or more holes 214 may be provided in the device to allow for the passage of sutures 310. The sutures 310 from one anchor can be connected to the opposing anchor in a running pattern, with each anchor interconnected. In other examples, a pair of anchors may be attached to each other via sutures in an intermittent pattern. The suture and anchor combination can hold the edges of the abdominal wall together until healing occurs. Holes may be provided in the front, back, button (if present), or multiple members of the anchor.

[0064] In yet another example, the anchor may incorporate a lock or shoulder 516, 116 as shown and described herein for attaching a ball (or bead) chain 320, 330 or similar structure (as shown in the perspective views of FIGS. 32, 33, and 34). The ball chain 320, 330 may also take the form of a strap with notches that engage with fingers or cams on the anchor, resisting movement of the strap or ball chain 320, 330 relative to the anchor. The anchor may be configured in various ways to hold the suture or ball chain 320, 330 (in place of a suture) in tension between two devices on either side of the closure. In another example, the bridging suture or ball chain 320, 330 may be replaced with one or more bridging threads, one or more staples (adjustable or fixed), or other structure that crosses from the anchor to a complementary anchor on the opposite side of the incision to align the abdominal wall tissue.

[0065] In many of the described embodiments, one or more prongs extending from the first member can be cut, broken, or melted above the second member (or third member) after assembly to limit the excess length of the prongs protruding above the second and / or third members into or through the subcutaneous tissue of the superficial layer of the abdominal wall. Also, ball (or bead) chains or straps (if used in place of sutures) can be cut, broken, or melted to a length that exceeds their attachment point to the base or platform.

[0066] In another example, the anchor, as described herein and shown in the perspective view of Figure 35, includes a first member having one or more prongs positioned from the interior to the exterior of the abdominal wall, with one or more prongs 102 extending through the thickness of the wall, and a second member exterior to the wall that is assembled to the first member by sliding over the prongs 102 from the first member. After the first member is assembled to the second member, energy is applied to the one or more prongs 102 of the first member to deform the prongs (see 107) and prevent the second member from sliding off the one or more prongs 102 of the first member (as shown in the perspective view of Figure 36).

[0067] Optionally, the prongs 102, 202, 402, 508, 602, 703, 802 of the first member may be cut or broken at a desired distance relative to the second member (as shown in the perspective view of FIG. 37 ) before or instead of applying energy to remove excess material. Energy can be applied to the prongs by direct thermal means (heat staking), ultrasonic (US) energy, infrared (IR) radiation, mechanical vibration or rotation (friction), or other methods available during surgery. This energy is used to raise the temperature of the prong material above its glass transition temperature (Tg) or melting temperature (Tm). Once the appropriate temperature is reached, pressure is applied to deform the prongs, creating a deformed portion, such as a “head,” that mechanically prevents the second member from sliding off the prongs of the first member. Alternatively, similar energy can be applied to the materials of both the first and second members to fuse the two members together.

[0068] The uses of the devices and methods described below are not limited to wound closure, but may include any number of additional therapeutic applications. Furthermore, such devices and methods may be applied to other treatment sites within the body. Modifications of the above-described devices and methods for carrying out the invention, combinations between different possible variations, and variations of aspects of the invention that are obvious to those skilled in the art are intended to be within the scope of the claims.

Claims

1. a first member having a first prong extending from a first surface configured to contact a first tissue region, the first prong having one or more ribs along a length of the first prong; a second member having one or more second piercing elements extending from a second surface configured to contact a second tissue region; a third member defining an opening, the third member having one or more cantilevered fingers configured to extend radially inward within the opening; Equipped with 10. A tissue anchoring assembly, wherein the one or more cantilevered fingers are configured to slide over the one or more ribs along the length of the first prong when the third member advances over the first prong in a first direction into contact with the second member, and movement of the third member on the first prong in a second direction opposite the first direction is restrained by the second member.

2. The assembly of claim 1 , wherein the first member further comprises one or more additional piercing elements each having a length less than the length of the first prong.

3. The assembly of claim 1 , wherein the first prong is deformable to secure in the opening in the second member.

4. The assembly of claim 1 , wherein the opening in the second member is deformable to secure to the first prong of the first member.

5. The assembly of claim 1 , wherein the opening in the third member is deformable to secure to the first prong of the first member.

6. The assembly of claim 1 , further comprising a connecting element configured to be secured to the tissue anchoring assembly.

7. The assembly of claim 6 , further comprising a second tissue anchoring assembly connectable to the tissue anchoring assembly via the connecting element.

8. 8. The assembly of claim 7, wherein the connecting element is configured to cooperatively approximate the tissue anchoring assembly attached to a first tissue region of tissue and the second tissue anchoring assembly attached to a second tissue region of tissue.

9. The assembly of claim 1 , wherein the one or more cantilevered fingers of the third member are constrained from bending about the first prong by the second member.

10. 10. The assembly of claim 9, wherein the force exerted by the second member on the third member inhibits movement of the third member about the first prong.

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