Negative pressure wound closure device

ES 2 806 552 T3

DESCRIPTION

Negative pressure wound closure device

A number of techniques have been developed for treating injuries, including injuries that result from an accident and injuries that result from surgery. Wounds are often closed with stitches or staples. However, the insertion of these mechanical closure techniques requires additional punctures or wounds to the skin, which can lead to tissue injury and, in the case of excessive inflammation, possible ischemia and tissue loss. In addition, mechanical wound closures such as staples and sutures can cause highly localized stresses at the insertion points that can impede and damage the normal wound healing processes of the skin.

In recent years, interest in the use of negative pressure devices for wound management has increased. Negative pressure wound management uses devices that remove fluid from the wound by applying negative pressure suction to the wound. Such negative pressures are believed to promote wound healing by facilitating the formation of granulation tissue at the wound site and aiding the body's normal inflammatory process while removing excess fluid, which may contain adverse cytokine bacteria. However, further improvements in negative pressure wound therapy are needed to fully reap the benefits of treatment.

A wound closure device that relies on negative pressure is known from US2011 / 0066096A1. It has an actuator that comprises an open-cell, compressible, elastic material that contracts medially when exposed to negative pressure.

The present invention relates to a negative pressure wound closure device that specifically exerts force on wound edges to facilitate wound closure. The device works to reduce the need for repetitive replacement of currently used wound filling material and can accelerate the rate of healing. The device simultaneously uses negative pressure to remove fluids from the wound and help close the wound.

In accordance with the invention, there is provided a negative pressure wound closure device comprising a wound filling material that can be placed within a wound opening, the wound filling material is configured to contract preferentially at the same time. along at least a first direction relative to a second direction upon application of negative pressure to the wound filling material, a fluid drainage device in fluid communication with the wound filling material of the wound closure device such that fluid drains from the fluid drainage device through the wound filling material after application negative pressure to the wound filling material, and a pad placed, during use, under the fluid drainage device between an abdominal cavity and a fascia, the pad provides lateral movement of the fascial tissue that covers the pad.

Previous negative pressure devices did not aid wound closure, but were used to drain fluids. By providing controlled movement of tissue during the healing process in conjunction with fluid drainage from wounds as described in connection with the present invention, a substantial improvement in the rate of healing can be achieved. Note that, depending on the size of the wound, increased negative pressure may be used.

In a preferred embodiment, a tissue gripping surface extends over an outer peripheral surface of the wound filling material and includes a plurality of tissue anchors that engage tissue at the wound margin. Upon application of negative pressure, the tissue at the wound margin is displaced to facilitate wound closure. A source of negative pressure, such as a vacuum pump, is coupled to the wound filling material to provide the negative pressure.

The wound filling material generally comprises a porous material, such as a foam. For embodiments employing tissue anchors, these can be integrally formed in the filler material. In other embodiments, the tissue anchors are provided on a separate cover or film that is secured to the filler material.

In preferred embodiments, the filler material includes a stabilizing structure that allows the material to collapse in at least one first direction and inhibits collapse in at least one second direction. The stabilizing structure can include regions of relatively rigid material surrounded by regions of relatively compressible material. In preferred embodiments, the stabilizing structure is an endoskeleton formed from rigid and / or semi-rigid materials.

In illustrative embodiments, the compressible material regions may include one or more sections of a compressible material configured, eg, sized and shaped, for association with one or more surfaces defined by the stabilizer structure. For example, a stabilizer structure can define a top surface, a bottom surface, and one or more side surfaces, each of which is associated with a corresponding section of compressible material. In illustrative embodiments, each section of the compressible material can be configured, eg, dimensioned and shaped, to match the corresponding surface. Therefore, the compressible material sections cooperate to wrap around the stabilizing structure, for example, to facilitate the features

ES 2 806 552 T3 structural as described in the present application. In some embodiments, a tissue gripping surface, as described above, may extend over an outer peripheral surface of the compressible material, for example, lateral sections of the compressible material that can engage the margins of an open wound.

In illustrative embodiments, the compressible material sections can define a plurality of surface features on the inner peripheral surfaces thereof. For example, sections of compressible material can define an egg-box pattern of ridges and valleys. Advantageously, the surface characteristics defined on the inner peripheral surface of the compressible material sections can be configured for operative association with an internal volume of stabilizing structure. In illustrative embodiments, each surface of the stabilizer structure can define a lattice pattern of stabilizer elements. Therefore, the surface characteristics defined on the inner peripheral surface of each section of compressible material can be patterned, for example, to match the lattice pattern of the corresponding surface of the stabilizer element. In illustrative embodiments, surface features defined on the inner peripheral surface of each section can provide tensile forces to the stabilizing structure, for example, during collapse thereof, to facilitate a structured collapse, for example, in one or more addresses. In some embodiments, the surface features defined on the inner peripheral surface of each section can be configured to impart a preselected force profile to the stabilizer structure, for example, during collapse of the same. In some embodiments, a preselected force profile can control the collapse of the stabilizer structure, for example by providing a non-uniform collapse, as well as resisting collapse in one or more directions and / or in one or more regions. The shaped wound filling material provides fluid transport through the device during the application of negative pressure. Accordingly, a preferred embodiment provides for continuous contact of the wound filling elements to facilitate continuous flow of fluid from the tissue margins and underlying tissue to the fluid outlet ports for drainage from the wound.

In certain embodiments, the stabilizing structure inhibits the collapse of the filling material along its height dimension, while allowing the filling material to collapse within the plane defined by the wound margins. This is useful in the case of abdominal surgery, for example, where the surgical incision is along a straight line and is opened laterally to form an oval-shaped wound. This generally oval-shaped wound can extend through muscle and fatty tissue with varying mechanical properties. Wound healing is best served by the use of an oval shaped framework adapted to preferentially collapse towards the original incision line. In preferred embodiments, the stabilizing structure promotes collapse of the filling material in a manner to effect approximation of the wound tissue. Fasciotomy wounds, or other wound dehiscences, or any open wound can be successfully treated using the modalities of the present invention.

The wound closure device can be used to treat wounds in the mediastinum, for pressure ulcers, for wounds on the extremities (arms or legs), etc. The wound closure device can also be used to treat wounds of different shapes, such as circular, square, rectangular or irregular shaped wounds. A plurality of wound closure elements can be formed to fit within a wound and can be attached to preferably close the wound in the desired direction. The different elements may comprise different materials or have different characteristics, such as the size of the pores and / or the size and distribution of the anchor to form a composite structure.

In one embodiment, an endoskeleton stabilizing structure includes a plurality of separate rigid members that form a shaded configuration. The endoskeleton allows the filler material to collapse along its width dimension and elongate to a lesser extent along its length dimension. In certain embodiments, a plurality of rigid members extend along the height of the fill material and inhibit collapse of the material in its height dimension, for example. According to certain embodiments, the endoskeleton comprises a network of interconnected rigid members that can articulate with each other during the collapse of the filling material. The endoskeleton may include lattice supports to inhibit tilt movement of the filling material. In some embodiments, the tissue anchors can be integrally formed on the endoskeleton. The endoskeleton can have bending elements with elastic properties such that the lateral force imparted by the skeleton is a function of displacement. The endoskeleton or frame prevents tilting of the wound closure device during use. The frame can include hollow tubes or cavities that alter the bending characteristics of the frame. The tubes or cavities can be used to deliver media to the wound.

A preferred embodiment of the invention uses a wound healing device for treating wounds in which seromas can form. The wound healing device may include openings to provide tissue contact through the openings to promote wound healing. The device may include removable drainage elements for the application of negative pressure.

In certain embodiments, the wound filling material includes a smooth bottom surface that has micropores to allow fluid to pass from the wound through the bottom surface and into the device for removal. The micropores can have a variable pore size and / or pore density to direct the vacuum force distribution from the negative pressure source. In some embodiments, the wound filling material may have varying internal pore sizes and / or pore density to direct the vacuum force distribution.

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In one embodiment, a negative pressure wound treatment component for handling and / or removing fluid is coupled to the wound filling material. A single source of negative pressure can be used for wound closure and fluid management / drainage. A sliding surface is provided at the interface between the wound closure and the fluid management components.

In yet another embodiment, the filling material includes removable portions to adjust the size of the wound closure device. The filler material can be provided with predetermined score lines to tear or cut portions of the material. In certain embodiments, the tissue anchor assemblies are embedded in the filler material and are exposed by removing excess portions of the material.

According to another embodiment, the fabric anchors are provided with a variable force profile. The force profile can vary depending on the depth of the tissue or the type of tissue involved. In some embodiments, the force profile of the tissue grasping surface varies around the perimeter of the wound closure device. The force profile varies, for example, by varying one or more of the length of the tissue anchors, the shape of the anchors, the materials of the anchors, and the density of the anchors.

A wound can be closed using a wound closure device as described above. For example, a linear incision in the skin overlying the abdomen provides access to a surgical site such as the gastrointestinal system of the human or animal body. Once completed, the wound should be treated with negative pressure therapy to facilitate recovery. Therefore, a wound closure device is inserted in accordance with preferred embodiments of the invention for wound closure treatment.

In a preferred embodiment, the wound closure device does not include tissue anchors, but instead uses a structure that has an expanding shape memory to fill the wound cavity. Therefore, the expansion frame exerts an expansion force when compressed such that the lateral peripheral elements of the device maintain contact with the wound margins around the peripheral surfaces of the wound closure device. The laterally directed outward expansion force is less than the closure force exerted on the tissue upon application of negative pressure which operates to close the wound margins and compress the wound closure device.

By using the negative pressure wound closure device of the invention, patients with large or severe wounds can be discharged or participate in rehabilitation physical therapy, change at home, and then return to have their wounds simply stitched up. By improving the treatment of wound closure and thereby reducing cost, the potential exists for these devices to be an important part of instruments used for wound care.

A preferred embodiment of the invention uses a wound healing device in combination with a wound closure device for treating wounds that require both components.

Other features and advantages of the present invention will be apparent from the following detailed description of the invention, taken in conjunction with the accompanying drawings, of which:

Figure 1A is a schematic perspective view of a negative pressure wound closure device.

Figure 1B is a cross-sectional view of the tissue-gripping surface of the wound closure device.

Figure 1C is a side view of one embodiment of the tissue gripping surface.

Figure 1D is a top view of the wound closure device showing xy stabilizers in phantom form.

Figure 1E is a cross-sectional view of the filler material showing xy stabilizers and stabilizers

z.

Figure 1F is a bottom view of the wound closure device showing a smooth bottom surface and micropores for removing fluid from the wound site.

Figure 1G is an elevation view of a peripheral stabilizer element.

Figures 2A and 2B are perspective and side views, respectively, of a supporting endoskeleton.

Figures 3A and 3B are perspective and side views, respectively, of a supporting endoskeleton with supporting structures.

Figure 3C is a side view of a supporting endoskeleton with x-shaped supporting structures.

Figures 4A-C illustrate a wound closure device that closes a wound.

Figures 4D-4E illustrate the use of a plurality of wound closure elements used for wounds of different shapes.

Figure 5 illustrates a two-stage treatment for negative pressure wound management and a negative pressure wound closure device (NPWT / NPWC).

Figure 6 illustrates an enlarged view of a preferred embodiment of the tissue anchor system.

Figure 7 illustrates an embodiment of a wound filling material having a tear or cut design to accommodate different wound sizes, with tissue anchors embedded within the filling material at predetermined cleavage points.

Figure 8A is a side view of a tissue gripping surface, illustrating different tissue anchors for different tissue types (Ti, T2) and the respective force profiles for the anchors, including the maximum force applied during closure to the vacuum (F1) and the force required to remove the anchors from the tissue (F2) without damaging the tissue.

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Figure 8B illustrates different designs for a tissue anchor.

Figure 8C illustrates an enlarged view of tissue anchoring elements on the peripheral surface of an oval wound closure device.

Figure 9A is a schematic illustration of a wound closure device positioned within a wound showing the different force profile around the wound margin in accordance with one embodiment.

Figure 9B illustrates the wound closure device of Figure 9A after a period of wound closure and healing, with the original wound configuration and wound closure device indicated phantom. Figures 10A and 10B schematically illustrate processes of use of a wound closure device in accordance with the present disclosure.

Figure 11A illustrates a cross-sectional view of a surgical site wound closure and drainage system in accordance with the invention.

Figure 11B illustrates a top view of a wound closure device and a tissue adhesion device.

Figure 11C shows a detailed perspective of a surgical drainage system in accordance with a preferred embodiment of the invention.

Figure 12 illustrates a cross-sectional view of the wound drainage and closure system used for a surgically treated pressure ulcer.

Figure 13 illustrates a sensor system for measuring wound closure force for a negative pressure wound closure system.

Figure 14 illustrates a pressure sensor system for measuring wound pressure.

Figure 15 illustrates a negative pressure wound closure system having a pressure controlled system.

Figures 16A and 16B illustrate perspective and exploded views of a preferred embodiment of the device.

Figure 17 shows a perspective view of the assembled device of Figure 16B.

Figures 18A and 18B show discretely shaped elements of wound padding within the associated framework.

Figure 19 illustrates an outer layer with tissue anchoring elements.

Figures 20A and 20B show anchoring elements adhered to tissue.

Figures 1A-1F illustrate one embodiment of a wound closure device 100. Device 100 includes wound filling material 102 that is sized and shaped to fit within a wound opening of a human or animal patient. In preferred embodiments, the filler material 102 is a porous, biocompatible material, such as an open cell polyurethane foam. The filler material 102 is also preferably collapsible, which means that its size can be reduced along at least one dimension (eg, length, width, height) by applying negative pressure to the filler material 102, while at the same Time inhibits contractions or contracts at a slower rate in another direction. More details on the devices and methods of the present disclosure can be found in U.S. application No. 13 / 365,615 filed on February 3, 2012.

Extending over at least one surface of the filler material 102, and preferably extending over an outer perimeter surface of the filler material 102 is a tissue gripping surface 104. In one embodiment, the tissue gripping surface 104 is a flexible covering, such as mesh film, that is secured to the outer perimeter surface of the padding material 102 and can expand and contract with the expansion and contraction of the padding material. 102. In one embodiment, the fabric grip surface 102 is a mesh film or a composite polyester mesh film, such as Parietex ™ mesh from Covidien (Mansfield, MA). The tissue gripping surface 104 includes a plurality of outwardly facing tissue anchoring elements 106, which in the preferred embodiment are a plurality of widely spaced tissue gripping points, hooks or elements, which may be integrally formed in the film of mesh.

Figure 1B is an edge view of device 100 showing tissue gripping elements 106 projecting from tissue gripping surface 104 at the periphery of wound filling material 102. Figure 1C is a side view of one embodiment, in which the tissue gripping surface 104 is formed of a flexible material, in particular a mesh-like material. Grippers 106 protrude from the page in Figure 1C. The flexible mesh-like material of the tissue grasping surface 104 allows the surface to expand and contract as needed with the expansion and contraction of the underlying wound filling material 102.

In other embodiments, the tissue gripping surface 104 with anchoring elements 106 may be integrally formed in the filler material 102. The tissue gripping surface and / or anchoring elements may also be formed using a resorbable material.

Tissue anchoring elements 106 are preferably provided on a complete outer perimeter surface of filling material 102. When filling material 102 is placed within a wound, anchoring elements 106 become buried within the tissue at the margins of the wound. wound and secure device 100 within the wound opening. The tissue anchoring elements 106 preferably extend over the entire surface of the wound margin to provide sufficient resistance in the gripping force. The tissue grasping surface 104 is preferably designed to allow the wound closure device 100 to be easily placed but also easily removed and replaced with a new device 100 or other wound dressing as needed (e.g., 2- 7 days later). Gripping surface 104 can be configured to have high gripping strength on at least a portion of its surface, but easily removable, for example, by pulling on an edge. The tissue gripping surface 104 is preferably designed to be removed from a wound without damaging the surrounding tissue. The

ES 2 806 552 T3 anchoring elements 106 are preferably designed to accommodate various tissue applications, such as muscle, fat, skin and collagen, and various combinations of these. Anchor elements 106 can also be designed to remain securely attached to particular tissues for a selected period of time in certain embodiments.

In embodiments where the gripping surface 104 is formed from a cover on the outer peripheral surface of the filler material 102, the gripping surface can be attached to the filler material 102 using any suitable technique, such as with an adhesive. or a mechanical clamping system. In a preferred embodiment, the tissue gripping surface 104 includes padding grip anchor elements, which may be spikes, that secure the gripping surface to the padding material. As shown in the cross-sectional view of Figure 6, for example, the gripping surface 400 comprises a thin mesh or film having two sets of spikes or similar anchoring elements, a first set 410 of gripping elements 412 of outward facing tissue that are designed to project into the tissue, and a second set 404 of elements 406 that project into the filler material to secure the gripping surface to the filler material. Returning to Figures 1A-1F, a negative pressure source 120, such as a pump, is coupled to the filler material 102 via a suitable coupling or conduit, such as tube 121. Additional tubes 107 may also be connected through a set of ports 105 spaced to spatially distribute the suction force so that the force exerted along the side wall 104 can be controlled separately from a fluid suction force. Negative pressure source 120 can be activated to apply negative pressure to fill material 102. In general, negative pressure causes a resulting pressure differential that causes fill material 102 to contract or collapse. As the filler material 102 contracts, the tissue gripping surface 104 grabs and pulls adjacent tissue, which is preferably tissue around a wound margin, resulting in tissue displacement, thus facilitating closure. of the wound. In accordance with the invention, the filler material 102 is designed to preferably collapse in at least one direction. For example, in the embodiment of Figure 1A, the filler material 102 includes a length and width dimension along the y and x axes, respectively, and a height along the z axis. In order to efficiently transmit negative pressure to the subcutaneous or other wound margins, it is preferred that the filling material 102 does not collapse centrally in the z-direction (like a pancake), so that the negative pressure action works predominantly in the x and y directions, or more particularly, in a two-dimensional plane along the margins of the wound, such as in an open abdomen or fasciotomy. It will be understood that, in some embodiments, the plane of the wound margins may be curved, as when the wound surrounds the curve of an abdomen or a leg.

Furthermore, in preferred embodiments, the filling material 102 is configured to preferably collapse in length and / or width (ie, along the x and y axes) to re-approximate the tissue at the wound margins. Note that certain types of wounds can be treated without the anchors described here.

There are several ways that the filler material 102 is configured to exhibit preferential collapse characteristics. For example, portions of the filler material 102 may be made of a stiffer material than the surrounding material, causing the filler material to preferably collapse in a particular direction. In one embodiment, the padding material 102 may include a stabilizing endoskeleton made of a suitable rigid material embedded within a collapsible padding, such as an open cell foam. Note that the amount of negative pressure applied can be adjusted depending on the size and shape of the wound. Pressures greater than 125mm, up to 250mm or more can be used to aid wound closure. The pressure can decrease over time as the wound contracts.

As shown in Figures 1D and 1E, for example, the filler material 102 includes a plurality of stabilizing elements 108 (shown in phantom) that allow the collapse of the filler material in certain directions, while inhibiting it in other directions. In this embodiment, stabilizer elements 108 include a plurality of stabilizer ribs, flexes, or rods, made of a suitably rigid or semi-rigid material, such as plastic. The rib structure is configured to preferably collapse along a specific axis to facilitate proper wound closure. The internal stabilizer elements 108 in this embodiment form a cross hatch pattern as seen in Figure 1D, although it will be understood that other configurations may be used. The space between the elements in the open state can be in a range of 1-2 cm, for example. Stabilizing elements 108 can be provided at different depths within the fill material, as shown in the cross-sectional view of Figure 1E, which helps to inhibit collapse in the z direction. In some embodiments, z-axis stabilizer elements 110 can be used to inhibit collapse in this direction. In Figure 1E, the z-axis stabilizer elements 110 are vertically extending projections from the ribs 108. In other embodiments, stabilizers separate from the z axis, such as rods or rib structures, may be employed.

In certain embodiments, device 100 may include a flexible cover that comprises a peripheral stabilizer element 111 that extends around the outer periphery of filler material 102, as shown in Figure 1E. The stabilizer element 111 may include a rib structure that reinforces the filler material 102 to prevent collapse in the z direction, as well as to inhibit tilting of the filler material in the zy and zx planes. Therefore, preferred embodiments of the filler material preferably contract in at least a first direction relative to a second direction upon application of negative pressure. So, for example, the width will shrink

ES 2 806 552 T3 at a faster speed relative to length, while height (wound depth) does not contract a substantial distance.

In some embodiments, tissue grip anchor elements 106 may be included in peripheral stabilizer element 111 and project from the periphery of filler material 102. This may be an alternative to, or an addition to, providing anchor elements 106 on a separate mesh or film. Peripheral stabilizing element 111 is preferably configured to expand and contract as necessary with expansion and contraction of wound filling material 102. Therefore, in a preferred embodiment, the stabilizer element 111 has sufficient flexibility to contract and expand in the x and y directions (i.e., around the periphery of the filler material 102), but has adequate stiffness along the direction. z (that is, along the height of the fill) to inhibit collapse or tipping in this direction.

One embodiment of a peripheral stabilizer element 111 is shown in elevation view in Figure 1G. Stabilizer element 111 includes a plurality of stabilizer rods 113, oriented to inhibit collapse in the z direction. The rods 113 are separated by a flexible material 114 which allows the stabilizer element 111 to expand and contract around the wound margin with the expansion and contraction of the underlying filling material. In this embodiment, tissue anchoring elements 106 are formed on peripheral stabilizer element 111 and project off the page.

One embodiment of an endoskeleton for a wound filling material of the invention is shown in Figures 2A and 2B. The endoskeleton includes a first set of xy stabilizer elements 108a and a second set of xy stabilizer elements 108b that are connected by a plurality of z-axis stabilizer elements 110. During the collapse of the filler material 102, the respective xy stabilizer elements 108a, 108b are collapsible in the xy directions, but the z-axis stabilizer elements 110 inhibit collapse in the z direction. In preferred embodiments, the stabilizing elements can articulate relative to each other during collapse. The joints 109 in the structure can be hinged or have a reduced thickness to accommodate flexing of the system. The flexes between the joints can also flex to accommodate the desired compression along the first, or lateral, axis 117 (see Figure 4B). Some expansion may occur along the second, or longitudinal, axis 119 as the device is compressed. The frame material may have a shape memory characteristic, which in combination with the suction force, defines the level of force applied to the fabric.

In another embodiment, shown in Figures 3A and 3B, the endoskeleton includes frame stabilizers 112 to inhibit tilt of the filler material 102 during collapse. The frame stabilizers 112 keep the upper xy stabilizers 108a and lower 108b aligned with each other as the filler material 102 collapses. In some embodiments, the frame stabilizers 112 can be rigid in certain directions and relatively less rigid in other directions (eg, the frame stabilizer may bow) to promote collapse in certain directions. Figure 3C illustrates an alternative embodiment having frame stabilizers 112 in an x-shaped pattern.

A preferred embodiment of the present invention employs an endoskeleton structure in which one or more of the stabilizing or flexing elements 108, 112 comprise hollow tubes or cavities 115. The hollow tube elements 108, 112 can be used to alter the elastic characteristics of the structure and therefore adjust the lateral displacement and the strength characteristics of the structure. The diagonal flexes 112 extend between the planes formed by the side members 108a and 108b.

The use of hollow tube elements in the elastic structure can also be used for the delivery of drainage fluid, drugs, oxygen, or other media to the wound. Tubes 108, 112 may contain post implant wound media that is subsequently released into the wound or may be connected to an external source. The tube walls may have pores that open to accommodate fluid flow into the wound from within the tube elements or cavities therein. The location of tubular elements, unlike solid rods or flexes, can be selectively placed within the structure depending on the preferred delivery location. For example, flexes 108 along the sidewalls can be used for delivery to regions that bond under negative pressure. Alternatively, flexures in the lower plane of the skeleton can be used for delivery to the underlying tissue structure or organs.

The stabilizing endoskeleton in certain embodiments may be made, in whole or in part, of a shape memory material. Various shape memory materials can be used to return from a deformed state (temporary shape) to their original (permanent) shape. This change in shape can be induced by an external stimulus or trigger. In one embodiment, the original or permanent shape of the endoskeleton is the collapsed configuration of the wound closure device, or the shape that will cause the wound to approximate. When the wound closure device is initially inserted into the wound opening, the endoskeleton is in a deformed or temporary state and embedded within the filling material. The endoskeleton can preferably return to its original or collapsed state or, alternatively, cause the device to expand to engage tissue. The collapse force of the shape memory endoskeleton may be additional or alternative to the vacuum force induced by the negative pressure source. In certain embodiments, the application of negative pressure to the wound closure device, which can return the endoskeleton to its original state.

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Figure 1F shows the bottom of wound closure device 100 in accordance with one embodiment. Device 100 in this embodiment includes a smooth bottom surface 115. This material can be a biocompatible film to be used, as provided in conjunction with the Renasys® system available from Smith & Nephew. A preferred embodiment can also be used with a meter as is also provided in the Renasys® system. Bottom surface 115 provides a low friction interface between wound closure device 100 and underlying tissue. In the case of an abdominal wound, for example, the underlying tissue can include internal organs, such as the intestines. The smooth bottom surface 115 allows the filler material 102 to contract and expand freely without interference from the underlying tissue and without damaging the underlying tissue. In a preferred embodiment, bottom surface 115 includes micropores 116 (shown in exaggerated size in Figure 1F for purposes of illustration) that allow fluid to pass through bottom surface 115 and into device i0o to remove it from the site of attachment. the wound. The wound closure device can also be inserted over a separate layer of material so that the device contracts on top of the sliding layer.

In some embodiments, the micropores 116 may have different sizes in different regions and / or may have different pore densities in different regions to direct different levels of force from the vacuum source to different regions of the device 100. Similarly, the filler material 102 can be designed with different internal pore sizes and / or pore densities to direct the distribution of forces from the vacuum source to different areas of the device 100.

Figures 4A-4C illustrate the use of the present device 100 to close a wound 200. The wound 200 includes a wound opening 201 and a wound margin 2θ3, as shown in Figure 4A. In Figure 4B, a wound closure device 100 is positioned within the wound opening 201 such that the tissue gripping surface 104 is in contact with the wound margin 203. In certain embodiments, the wound closure device 10 can be formed by cutting or tearing the filling material 102 to the appropriate size, and then attaching the tissue gripping elements 106 around the periphery of the filling material 102. In one embodiment, the gripping elements 106 are attached by attaching a two-sided mesh of spikes to the filler material 102, where the outward-facing teeth are designed to grip the tissue and the inward-facing teeth are designed to secure the mesh. to the filler material 102. A tube 121 connects the filler material 102 to the source of negative pressure. The wound area 200, which includes the filler material 102, can be covered with a sealing cloth 205.

In the embodiment of Figure 4B, the filler material 102 includes a plurality of internal stabilizing elements 108 (shown in phantom) that provide the filler material 102 with a preferential collapse characteristic. Stabilizing elements 108 help control the collapse of the filling material 102, and the resulting displacement of the tissue around the wound margin 203, in the x and y directions. Additional stabilizing elements may be provided to control or inhibit collapse along the z direction. As previously described in connection with Figure 1D, stabilizer elements 108 in this embodiment include a shaded configuration.

Figure 4C illustrates wound 200 after application of negative pressure to wound closure device 100. Tissue anchoring elements 106 grasp tissue margins 203 and cause displacement of tissue margins 203 as they the filler material 102 collapses. As seen in Figure 4C, the filling material 102 collapses in the x and y directions such that the tissue is re-approximated at the wound margin 203. In the embodiment of Figures 4B and 4C, the shaded configuration of stabilizer elements 108 helps to control the direction of tissue displacement during collapse. The greatest amount of tissue shift in this embodiment is in the central region of wound 200, where aperture 201 is widest, and this shift is primarily inward along the x-direction. Away from the central region (for example, at the top and bottom of the wound as shown in Figures 4A and 4B), where the wound margins are closer together, less displacement is needed in the x direction to return to approximate the fabric.

In general, inward collapse of the filler along the y direction is undesirable. In fact, during tissue approach, wound 200 will tend to elongate in the y direction as the wound margins close in the x direction. In preferred embodiments, the internal stabilizing elements 108 promote collapse of the filling material in a manner that provides re-approximation of the wound. In the embodiment of Figure 4-C, for example, during the collapse of the fill, the striped stabilizer elements 108 straighten relative to each other, similar to an accordion gate. The largest offset is in the central region of fill 102, along the x direction. Stabilizers 102 generally inhibit internal collapse along the y direction. As stabilizers 108 straighten, they can also facilitate wound elongation in direction and to allow proper tissue approximation. Different shaped wounds 220, 240 are shown in Figures 4D-4E in which a plurality of wound closure elements are used in combination to fill the wound. In Figure 4D, elements 222, 224, 226 and 228 have different shapes that are cut or trimmed to size to substantially fill the wound which in this example is circular in shape. When negative pressure is applied, the elements work together to close the wound in the desired direction. Figure 4E illustrates a rectangular wound 240 using closure elements 242, 244, 246, 248, and 250 to fill wound 240. The tissue anchors of each closure element can also be attached to the adjacent closure element (s). With the suction applied to the central elements 224, 250, the neighboring elements are drawn towards the central elements to close the wound.

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The wound closure device 200 may remain in this configuration for a period of several days or weeks to facilitate closure and healing of the wound 200. After a period of healing, the device 100 can be removed and optionally replaced. for a smaller device. After the wound has been sufficiently closed using the present device, it can be sewn closed.

Figure 5 illustrates a two-stage negative pressure wound treatment and negative pressure wound closure device (NPWT / NPWC) 300. The device includes a negative pressure drainage / fluid handling component 301, as known in the art, connecting to an overlying negative pressure wound closure device 100. The wound closure device 100 includes a collapsible wound filling material 102 and a tissue gripping surface 104, substantially as previously described. Tube 121 connects device 300 to a single pump to apply negative pressure to wound closure and wound treatment components. Device 300 may include interchangeable parts depending on the need for a specific wound application. In one embodiment, device 300 is used for abdominal wounds in one example, and can also be used for mediastinal and fasciotomy wounds.

In a preferred embodiment, the filling material 102 can slide into the total NPWT / NPWC device 300. The filling material 102 includes a sliding surface 303 at the interface between the wound closure and the fluid management components. The sliding surface may comprise a treated surface or a separate layer of material.

Sliding surface 303 facilitates free contraction of the wound closure component, without interference from the fluid management component. The underlying fluid management component 301 can be specifically configured to manage fluid only and not generate granulation, as this can slow or inhibit slippage.

Figure 6 illustrates an enlarged view of a preferred embodiment of the tissue anchor system 400. One side of the material 402 has a first group of anchor elements 404 that are adapted to grip the filler material. The first anchor elements 404 can be shaped to grip the filler material such as with a distal hook shape 406. Since the 402 material must bond to the filler with a certain gripping force to apply a sufficient tensile force on the fabric, a specified level of force F must be applied to remove the hooks from the filler material that exceeds the tensile force that is applied to fabric. Similarly, since the fabric to be held by the material 402 has different structural characteristics than the filling material, a second group of anchoring elements 410 adapted to grip the fabric may have a different shape and gripping force than the first. anchor elements. In this embodiment, the tips 412 may have bilateral tips 414 that tend to collapse upon insertion into tissue and yet expand when pulled in an opposite direction so that some tensile force can be applied to the tissue. However, the tips or the cone-shaped anchor element have a release force such that the tips can be manually removed from the tissue without causing injury.

Figure 7 illustrates one embodiment of a wound filling material 500 that has a tear or cut design to accommodate different wound sizes. The filler material 500 includes natural cleavage lines 501, 503, 505 that allow the size of the material to be adjusted to fit the wound to be closed. The material 500 is designed to be torn or cut at the cleavage lines to remove one or more portions 502a, 502b, 502c of the material and to adjust the size of the material. The tissue anchor assemblies 506a, 506b, 506c, 506d are embedded within the filler material at predetermined cleavage points, and are exposed as the respective outer portions 502a, 502b, 502c are removed. Tissue anchors 506a, 506b, 506c, 506d can be associated with a stabilizing structure of the endoskeleton, as previously described in connection with Figures 1-4. In some embodiments, the stabilizing endoskeleton structure may include predefined attachment or attachment points to remove portions of the stabilizing structure as the size of the filling material 500 is adjusted.

Figure 8A is a side view of a tissue gripping surface, illustrating different tissue anchors 601, 602, 603, 604 for different types of tissue (Ti, T2). An example of the respective force profiles for the anchors is also illustrated, including the maximum force applied to the tissue during vacuum sealing (F1) and the force required to remove the anchors from the tissue (F2) without damaging the tissue. In one embodiment, the characteristics of the tissue anchors are varied to provide different force profiles across the interface between the wound closure device and the surrounding tissue. For example, for the upper layers of tissue, Ti, anchor 601 is designed to bond with collagen material, such as in the dermis. Anchor 601 has a different force profile (F1 and F2) in the upper tissue layer (s), Ti, as shown in Figure 8A. In the lower layers of T2 tissue, the anchors 602, 603, 604 are designed to bind to the fatty tissue of the subcutaneous layer. Generally, a smaller force profile is needed to secure the anchors to this tissue.

The characteristics of the anchors and their resulting force profiles can vary based on a number of parameters, such as the length of the anchor, the shape of the anchor, the structure of the gripping characteristics, the materials used for the anchor, the relative flexibility / stiffness of the anchors, and the spacing / density of the anchors. In Figure 8A, for example, the anchor 601 is significantly longer than the anchors 602, 603, which in turn are longer than the anchors 604. Figure 8A also illustrates the variation in the density of the anchors, as shown shown at 602, 603, and 604. Figure 8B illustrates three examples of different types of gripping features, including a 605 spike configuration, a 606 stepped hook configuration, and a 607 stepped spike configuration. Other suitable gripping features can be used, such as the anchor elements 620 shown in the view at

ES 2 806 552 T3 enlarged perspective of Figure 8C. The anchoring process can be enhanced by suturing the filler material or by supporting the endoskeleton to the tissue. The force profile can also be varied by controlling the vacuum force distribution in the filler material, such as by varying the pore size and / or pore density of the filler.

The wound closure device of the invention can be provided in kits to close different types of wounds (eg abdominal, fasciotomy, etc.). The tissue grip surface can be optimized for different tissue types such as collagen, fat tissue, and muscle, depending on the tissue structure at the wound site.

In certain embodiments, the force profile of the wound closure device is variable around the periphery of the wound. An illustrative embodiment is illustrated in Figure 9A, which shows the force profile (f1) exerted on the wound margins at a plurality of locations at the periphery of the wound. In this embodiment, the largest f is in the central region of the wound filler 102, where the wound opening is widest and the wound closure force is totally or almost totally in the x-direction. Moving towards the upper and lower regions of the wound, the closing force (f1) is much smaller. One reason for this is because the wound opening is much smaller in these regions, and a much smaller force is needed to re-approximate the tissue. Furthermore, the inward force exerted in these regions includes components in the x and y directions. Therefore, a smaller force profile is preferable to avoid internal tissue collapse in the y-direction. As illustrated in Figure 9B, as the wound closes and heals from an initial state (indicated by dotted lines) to a later state (indicated by solid lines), it elongates in the y direction. Therefore, the displacement of the tissue anchors 701a and 701b is exclusively in the x-direction and in the direction of the closing force (f1), while the displacement of the tissue anchors 703a, 703b is both inward in the x direction (in the direction of the closing force) and outward in the y direction (opposite the direction of the closing force). Therefore, a smaller f 1 is preferable in these regions to provide more play between the anchoring elements and the surrounding tissue. Alternatively, the wound closure device is configured so that it does not elongate, but does not change its length along the long axis 720.

Variation in the force profile around the periphery of the wound closure device can be achieved in a number of ways, such as varying the spacing / density of the tissue anchors, the types of anchors, the length of the anchors, or the configuration. of them, etc. For example, in Figures 9A and 9B, anchors 701a, 701b are longer and penetrate deeper into tissue compared to anchors 703a, 703b. The force profile can also be varied by controlling the vacuum force distribution in the filler material, such as by varying the pore size and / or pore density of the filler.

In one embodiment, a method of fabricating a wound closure device of the disclosure includes forming a stabilizing endoskeleton of rigid or semi-rigid material and forming a collapsible filler material on the endoskeleton. The stabilizing endoskeleton can be formed by a molding process, and can be molded as an integral unit or into one or more components that are then assembled to form the endoskeleton. Different components of the endoskeleton can have different thicknesses and / or degrees of stiffness to provide different levels of stiffness and flexibility in different directions. The endoskeleton can be assembled by joining components, such as by using a suitable adhesive or other joining process, such as by inserting rods into tubular segments. In certain embodiments, at least some of the components can be assembled to provide pin joints. In preferred embodiments, the filler material is formed by mixing appropriate measured amounts of constituent substances (eg, isocyanates, polyols, catalysts, surfactants, blowing agents, and the like in the case of polyurethane foam), distributing the reaction mixture into a mold, and then cure and demold the material. Optionally, the material can be cut or trimmed to the finished shape. In preferred embodiments, the endoskeleton support structure is assembled and placed in the mold, and the filler material is molded around the endoskeleton. An example of a suitable biodegradable foam product for the present wound closure device, and methods for making such foam, are described in US published application No. 2009/0093550 to Rolfes et al.

Illustrated in Figure 10A is a method of performing a surgical procedure 800 using a wound closure device in accordance with preferred embodiments of the disclosure. After preparing the patient 800 for surgery, an incision 820 is made to expose the surgical site, generally in the abdomen. After the procedure is performed, the wound is prepared 830 for closure. The proper size and shape of the wound closure device is selected 840 with the peripheral tissue fixation members positioned around the circumference or surface of the outer wall of the device. The device is inserted 850 into the wound and the tissue attachment elements are inserted 860 into the tissue. Negative pressure 870 is then applied to exert a closing force at the wound edges. Depending on the particular application, large wounds may require placement 880 of a second, smaller closure after removal of the first, larger device. Finally, device 890 is removed and the wound closed, typically by suturing.

In a preferred embodiment where tissue anchors are not used, a method 900 for wound closure is described in relation to Figure 10B. In this modality, the patient is prepared for surgery 910, an incision or other means is used to open or expose 920 the wound, and the procedure is performed 930. The appropriate wound closure device for the shape of the wound is selected 940 and 950 is inserted into the wound. In this embodiment, the wound closure device flexes or expands under its inherent expansion characteristics to contact the wound margins. The wound is sealed 960 and negative pressure 970 is applied. Sufficient negative pressure is applied so that

In ES 2 806 552 T3 the expansion force exerted by the device on the wound margin is less than the closing force applied to the wound and to the device so that the wound closes at a controlled rate. This provides a procedure in which the device maintains contact with the wound margin and therefore reduces the occurrence of device typing within the wound during closure. As in previous embodiments, the device can be replaced 980 as needed prior to wound closure 990, however, the need for replacement is reduced by avoiding the formation of spaces between the wound margins and the device.

Certain types of wounds that can be treated with negative pressure wound therapy involve incisional separation of subcutaneous tissue to form a wound opening. This procedure is often used to access underlying structures, organs, or injuries. Lateral displacement of the subcutaneous tissue can contribute to additional difficulties in treating the resulting wound.

Illustrated in Figure 11A is a wound incision 900 in which tissue region 906, 908 has been separated to access an underlying tissue region 902 for treatment. Lateral displacement of regions 906, 908 from their respective positions overlying region 902 has caused greater separation between displaced regions 906, 908 and the underlying structure. In the case of an open abdominal wound, the underlying structure may be the large and small intestine, which may be subject to infection and / or elevated fluid pressure.

In addition, there may be separation between the fascia 909, 911 and the abdominal muscle and overlying subcutaneous tissue 906, 908. Consequently, as shown in Figure 11A, the system includes pad 907 positioned between the abdominal cavity 902 and the fascia. which can be used to allow sliding movement and use negative pressure. Optionally, the system also includes a seroma pad 925, described in more detail below, positioned between the fascia and overlying tissue and wound closure element 918. Negative pressure region 918 may be in fluid communication with underlying layer 925, extending laterally to sections 914 and 916 that are located between overlying tissue 906, 908, respectively, and the underlying abdominal muscle and structure of the fascia 911, 909. One or both sides of sections 914, 916 may have tissue anchors 926, 928 as described above. Dotted line 921 indicates a region through which negative pressure is applied to all three layers.

After insertion of layer 925, compressible wound closure element 918 is inserted followed by sealing cloth 905 and closure device 940 and fluid control tube 942. Pad 907 operates to drain fluid 910 of the abdominal cavity by negative pressure through elements 925 and 918.

In the event that adjacent tissues need treatment using negative pressure or require stabilization such as by pad 925, a wound management system can be used in combination with the systems and methods described herein. Shown in Figure 11B is a top view of a system utilizing a 918 negative pressure closure system as generally described herein and a seroma pad or tissue adhesion element 925. The shape of the pad 925 may also be be circular and have no openings or fabric anchors, for example. The number of drains can be in a range of 6-10 extending in a radial direction with uniform angular spacing between the drainage elements.

Therefore, a preferred embodiment of the present invention provides a surgical drainage pad or device 925 for the prevention and treatment of seromas, as well as for general use in promoting surgical wound drainage and wound closure. The drainage device may include a plurality of drainage tubes 935 disposed on a substrate called an adhesion matrix, which is designed to promote tissue adhesion within the wound or seroma space. The adhesion matrix has a conformable configuration and is made of a compatible material that has flat surfaces that can be bent to conform to the shape of the wound space.

In a preferred embodiment, the adhesion matrix contains a plurality of openings 927, or spaces in the matrix material, that allow tissue contact through the matrix to promote adhesion and wound closure. Therefore, a tissue surface on a first side of the matrix may directly contact a tissue surface on a second, or opposite, side of the matrix to promote rapid wound healing and stabilization. The number, size, and distribution of openings 927 extending through the die can be selected based on the geometry of the wound. For abdominal wounds, for example, the drainage tubes can be placed in a fan-shaped matrix with a plurality of three or more tubes extending from a manifold. The matrix and / or tube can be cut or shaped by the user to fit the shape of the wound. The matrix can also be used as a drug vehicle to aid in the administration of a drug to a patient. The matrix may optionally include a layer of adhesive on at least a portion of any of its surfaces. Drainage tubes can be removed from the device once drainage flow is sufficiently reduced, and the adhesion matrix can remain within the body, where it degrades and absorbs over time, remaining in place to optimize tissue healing . The matrix may comprise a porous biodegradable polymeric material. As the plurality of tubes extend from a single exit site into the wound with spaced distal ends, a user can easily remove all tubes simultaneously from the wound.

As shown in more detail in Figure 11C, the surgical drainage device 925 may include a tissue anchoring system, whereby the device is mechanically attached to surrounding tissues through a series of

ES 2 806 552 T3 surface tips or hooks 926, 928. These surface structures can be located on any exposed surface of the bonding matrix. When the device is implanted, surrounding tissues can be pressed against the tips or hooks to embed them within the tissue and anchor the device. The use of shallow tips or hooks can be used in combination with a surgical adhesive, providing a much stronger bond between tissue layers than the adhesive alone, and providing temporary adhesion while the adhesive hardens. The structure of the hooks can take various forms depending on the fabric to which they are intended to be attached. Longer hooks can be used for loose tissue like fat or connective tissue, while shorter hooks can be used for denser tissue like muscle. Stiffer stem anchors can be used to penetrate denser tissues.

Another aspect is a system for surgical wound drainage. The system includes the drainage device coupled to a wound closure device 918 as generally described herein along with a vacuum source, such as a pump, and a tube connecting the vacuum source to the drainage tubes of the device. sewer system. The system can optionally also include a fluid trap to collect drained fluid and a control unit to monitor and control vacuum application and fluid collection. Other components of the system may include a vacuum or pressure gauge, a flow meter, and a computer to monitor vacuum and flow and regulate vacuum or flow. Pressure measurement can be used to monitor the level of applied pressure using a feedback control loop. Wound closure device 918 may include the endoskeleton structure as described herein that has external ribs extending from the external surface and bending arms or beams that have an intrinsic restoring force that varies as a function of position. of each bending element. Different bending elements can have a different restoring force depending on their position within the framework as shown in Figures 2A-3C, for example. The endoskeleton accommodates expansion to fill the wound cavity and will collapse in a well-defined manner in response to wound collapse under negative pressure. As described herein, foam or other padding material can be used within the flex system. The endoskeleton can have a multilayer structure with the different layers collapsing along individual planes of the three-dimensional structure within the wound without tilting the structure.

A method of treating or preventing a seroma, or promoting drainage or closure of a surgical wound is described. The method includes placing the drainage device described above in a seroma, or a surgical wound, such as a wound at risk of forming a seroma, and allowing the device to drain fluid from the wound for a period of time. The device may include surgical adhesive and / or tips or hooks on its surface to create adhesion between layers of tissue within the wound and to anchor the device in place. Drainage can be by gravity flow or it can be vacuum assisted by connecting a vacuum source to the device's drain tubes, using a manifold to fuse the flow paths of the drain tubes to a common drain tube for collection. . Negative pressure applied to the drainage tubes can be used to hold the tissue layers above and below the device together until a surgical adhesive has set, or until the wound healing process binds to the tissues. . The application of negative pressure further facilitates contact between tissue on opposite sides of the matrix through openings in the matrix to promote tissue adhesion. This improves the rate of healing and at the same time provides drainage. Optionally, the drainage tubes of the device have openings 933 that extend along their length and can be withdrawn from the body after the drainage flow is reduced, thus reducing the resorption load on the body. Removal of drain tubes can be facilitated by including drain tube channels, or drain tube release tabs, within the adhesion matrix. Release of the drain tubes is accomplished by sliding the tubes out of the channels or by properly maneuvering the drain tube assembly to break the release tabs. The adhesion matrix is ​​allowed to remain in the seroma or surgical wound where it is resorbed over time.

The flow rate of the drain tubes can be regulated by flow control elements. Flow rate can also be measured or fluid pressure can be measured with ultrasound devices or other methods. The system can also be used in conjunction with wound dressings that can also be attached to a negative pressure source to remove fluid from the wound.

Also described is a negative pressure wound closure device 1000 for the treatment of surgically repaired ulcers as shown in Figure 12. This type of wound is often characterized by a narrower wound opening 1001 which may have a generally shaped circular or oval. The surgeon can use this opening to access tissue to be removed to form a laterally extending cavity 1005. A first wound closure element 1007 extends laterally to regions 1012, 1015 which may include tissue anchors 1014, 1016 that serve to attach regions 1012, 1015 to tissue flaps 1004, 1006 above regions 1012, 1015, respectively, as well as underlying tissue 1026. Anchors 928 can also extend in a lateral direction. The second wound closure element 1020, as described above, is in fluid communication with the adhesion elements 1007, and allows the application of negative pressure to the channels 935 of the regions 1012, 1015 that can be employed in the Figure 12. The closure element may include openings 927 that allow tissue contact through regions 1012 and 1015 as these elements are compressed under negative pressure.

A sensor system 180, 182 is illustrated in Figure 13 for measuring the wound closure force that can be exerted on the side walls of the tissue being joined. Sensor elements 180, 182 can be mounted on the

ES 2 806 552 T3 internal flexible frame 108 or the endoskeleton of the system and measure the amount of force exerted laterally on the tissue. For example, as the level of negative pressure applied to wound closure element 100 increases, sensors measure the increased force exerted on tissue by anchors 106. Additional sensing elements can be mounted on the side walls of the device 100, to measure the force distribution across the side walls. The bending elements 108 may have a selected resistance to allow controlled collapse of the device 100.

A pressure sensor system in place to measure pressure on underlying tissue is shown in Figure 14. Sensor elements 320, 322 can measure pressure at sliding interface 303 or at the bottom of panel 301, which can measure the amount of negative pressure at the tissue interface such as in the abdominal cavity. This can be used to monitor the downward pressure in the abdominal cavity that may arise during compression of the frame 104.

The systems of Figure 13 and Figure 14 may optionally include a feedback control system 1200 that controls a negative pressure level and / or distribution within the system. Such a feedback system 1200 is shown in connection with Figure 15. Sensors 180, 182 can be connected to processor housing 360 using cable 350 and pressure sensors 320 and / or 322 can measure fluid pressure such that sensor data is transmitted to processor housing 360 using cable 352. A data processor 366 can be programmed to adjust the pressure applied through tube 121 to prevent injury to the patient and optimize the rate of wound healing. Data can be displayed on screen 362 and a control panel 364 provides a user interface for system operation.

Figure 16A illustrates another illustrative wound closure device 2100 of the present disclosure. Device 2100 includes a wound filling material 2102 that is sized and shaped to fit within a wound opening 2201 of a human or animal patient. Device 2100 is further associated with a negative pressure source 2120, as described with respect to Figures 1A-1F, which can be coupled to filler material 2102, for example, by a suitable coupling or conduit. As noted above, negative pressure source 2120 can be activated to apply negative pressure to fill material 2102. In general, negative pressure causes a resulting pressure differential that causes device 2100 to contract or collapse.

Figure 16B depicts a break away view of the illustrative wound closure device 2100 of Figure 16A. Illustrative device 2102 advantageously includes a stabilizing structure 2101, eg, an endoskeleton structure as described above, and a collapsible filler material 2102, eg, foam or other filler material as described herein, over the stabilizing structure. 2101. As depicted, fill material 2102 includes a plurality of sections of 2102A-D, configured for association (e.g., sized and shaped to match) with each of an upper surface 2101A, a lower surface 2101B, a first surface side 2101C and a second side surface 2101D of the stabilizer structure or movable frame 2101. Therefore, sections 2102A-D of filler material 2102 cooperate to surround stabilizer structure 2101, for example, forming a cover around stabilizer structure 2101, as depicted in Figure 17. The device may have a layer cover 2105 that is used to contact at least the wound margins so that the layer extends around the outer surface of the filling 2102. In illustrative embodiments, stabilizer structure 2101 and sections 2102A-D of filler material 2102 can be configured to define a cavity to facilitate application of negative pressure to device 2100, for example, using negative pressure source 2120.

In some embodiments, each section 2102A, 2102B, 2102C, or 2102D of filler material 2102 can define a plurality of surface features 2103 on its inner peripheral surface. For example, each of the depicted sections 2102A, 2102B, 2102C, or 2102D of compressible material 2102 defines an egg-box pattern of bumps 2103A and valleys 2103B. Advantageously, surface features 2103 defined on the inner peripheral surface of sections 2102A-D of filler material 2102 can be configured for operative association with an inner volume of stabilizing structure 2101.

As described in previous sections, each surface 2101A, 2101B, 2101C, or 2101D of stabilizer structure 2101 can define a lattice pattern of structural elements that include frame elements or stabilizers in the xy plane (such as stabilizer elements 2108 of Figures 1A -1F) and z-axis stabilizing elements (such as stabilizing elements 2110 of Figures 1A-1F). Therefore, the surface characteristics 2103 defined on the inner peripheral surface of each section 2102A, 2102B, 2102C or 2102D of the filler material 2102 can be configured, for example, with a pattern, to match the lattice pattern of the corresponding surface 2101A, 2101B, 2101C or 2101D of structural element 2101. For example, as depicted in Figure 16, the surface features 2103 defined on the inner peripheral surface of the upper and lower sections 2102A and 2102B are configured such that the valleys 2103B correspond to the stabilizing elements in the xy plane. Similarly, the surface features 2103 defined on the inner peripheral surface of the first and second side sections 2102C and 2102D are configured such that the valleys 2103B correspond to the stabilizing elements on the z axis. Therefore, the protrusions 2103A or pattern elements extend into an internal volume of the structural element 2101, thus providing tensile forces to the stabilizing structure 2101,

ES 2 806 552 T3 for example, during the collapse of the same. In illustrative embodiments, filler material 2101 can be configured to provide prestress to stabilizer structure 2101.

In some embodiments, the tensile forces applied by protrusions 2103a can facilitate a structured collapse of structural member 2101, for example, in one or more directions. For example, surface characteristics 2103 defined on the inner peripheral surface of each section 2102A, 2102B, 2102C, or 2102D of filler material 2102 can be configured to impart a preselected force profile to stabilizer structure 2101, for example, during collapse. Of the same. In some embodiments, the preselected force profile can control the collapse of structural member 2101, for example, by providing non-uniform collapse of the filler material such as by resisting collapse in one or more directions and / or in one or more regions. Referring to Figures 18A-18B, different force profile configurations are depicted for individual protrusions or elements 2103A. In Figure 18A, protrusion 2103A is configured to resist compression of the associated stabilizer elements 2108 of structural element 2101 in both the x and y directions. Therefore, the protrusion is configured to provide uniform tensile forces to the stabilizer structure 2101, for example, during collapse thereof, both on the x-axis and on the y-axis. In Figure 18B, protrusion 2103A is configured to provide greater compressive strength of the associated stabilizer members 2108 of the structural member in the y direction than in the x direction. Therefore, the protrusion is configured to provide greater tensile forces to the stabilizer structure 2101, for example, during collapse thereof, on the y-axis than on the x-axis. In another embodiment, a smaller protrusion is used to provide a delayed or lower compressive strength relative to the larger protrusion. Pattern elements in adjacent regions within the frame preferably contact each other to facilitate fluid flow under negative pressure. Therefore, some regions of stabilizer structure 2101 can be configured to collapse earlier or faster than other regions while maintaining fluid flow.

Referring to Figure 19, illustrative embodiments, the side sections 2102C and 2102D of the filler material 2102 may include a tissue grip surface 2104, such as the tissue grip surface 2104 of Figures 1A-1F, which extends on an outer peripheral surface of wound filling material 2102. As an alternative, note that a separate covering layer of material, such as a film or mesh, as described above, may extend around the outer surfaces of the wound filling. This layer can also include tissue anchors in a further preferred embodiment as described herein, so that the device can adhere to the wound margins. The tissue gripping surface 2104 can be an integral part of the fill material or it can be a separate layer, for example, secured to the fill material 2102 using any suitable technique. In illustrative embodiments, grasping surface 2104 may include a plurality of tissue anchoring elements 2106 configured to engage tissue at a wound margin. Therefore, referring to Figure 20A, when the filler material 2102 is placed within a wound 2200, the anchoring elements 2106 become buried within the tissue at the margins of the wound 2203 and secure the device 2100 within the wound. wound opening 2201. As the filler material 2102 contracts, the tissue gripping surface 2104 grabs and pulls on the adjacent tissue, which is preferably the tissue around the wound margins 2203, resulting in displacement of the tissue, thus facilitating removal. wound closure.

While the invention has been described in relation to specific methods and apparatus, those skilled in the art will recognize other equivalents to the specific embodiments in the present disclosure. It is to be understood that the description is by way of example and not as a limitation on the scope of the invention and these equivalents are intended to be encompassed by the claims set forth below.