The invention relates to a device for implanting at a treatment site for the drainage of fluid from the site or for the delivery of fluid to the site. In particular, the device is bioresorbable. The invention also relates to a system comprising the device and a means for applying negative or positive pressure to aid in reducing dead space and improve drainage of fluid from a treatment site or delivery of fluid to a treatment site. The invention further relates to a method of draining fluid from a treatment site or delivering fluid to a treatment site using the device of the invention, and to a method of manufacturing said device.
The drainage of fluid and the reduction of dead space from surgical or traumatic wounds is often a critical factor in the timely and effective recovery of a patient. Currently, there is no good solution for eliminating dead space at the time of surgery. Suturing provides linear closure rather than offering closure across the entire separated tissue plane. Surgical drains are only partially effective in removing fluid and do not deal with the primary issue of closing dead space immediately following surgery. Tissue adhesives have not proven to be reliably effective, and manually suturing across a total area only provides limited amount of localized closure.
Seroma or hematoma formation post-surgery or trauma can hinder recovery. Seromas and hematomas are pockets of serous fluid or blood that accumulate at wound sites. In the absence of adequate drainage, poor healing, infection or dehiscence may lead to a requirement for additional surgery and longer hospital stays. Seromas and hematomas are common after reconstructive plastic surgery procedures, trauma, mastectomy, tumour excision, caesarean, hernia repair and open surgical procedures involving a lot of tissue elevation and separation.
While reducing dead space and providing drainage of fluid from a wound site is highly desirable in many instances, it is useful in other circumstances to be able to deliver fluid directly to a wound site to aid in the wound healing process. For example, instilling antimicrobial solutions locally into infected tissue is useful for managing infections. Similarly, instillation of local anaesthetics can aid pain management.
Numerous devices are available which can be implanted at the site of treatment to enable drainage of fluid. These range from simple silicon tubes comprising drainage holes through to manifolds of structures of various shapes made from decellularised tissue. For example, U.S. Pat. No. 7,699,831 describes a wound drainage assembly having a housing configured for placement in an interior wound site. A foam sponge is located in the housing for absorbing fluid from the wound site. Tubing is coupled to the housing and is connected to a source of negative pressure outside the body. The negative pressure causes the fluid to flow from the foam sponge to an external collection site.
Some drainage devices must be removed from the body after the wound site has been drained for a period of time. Removal of such devices can cause discomfort or pain for the patient or require an undesirable further surgical procedure, while the need to remove the device limits the ability to position the device to provide effective treatment across an area. However, other drainage devices are constructed of a material capable of being absorbed by the body.
US 2015/0320911 describes tissue-based implantable drainage manifolds. The manifolds may comprise decellularised tissue formed into sheets, tubes or columns. Negative pressure may be applied to assist drainage from the wound site into the manifold and to the exterior of the body via tubing. The tissue-based manifolds do not need to be removed following completion of the drainage procedure. The manifold structures also provide a scaffold for the migration and proliferation of cells from surrounding native tissue.
However, while a number of existing drainage structures are bioresorbable their construction typically involves materials which are completely synthetic and are constructed using manufacturing techniques such as injection moulding or extrusion which create continuous tubes or structures comprising thick wall sections or structures with a high amount of synthetic mass.
The implantation of synthetic materials can contribute to elevated levels of inflammation that typically manifest within the body following implantation, most particular in sensitive and vascular areas such as the pelvic floor or abdominal wall. Many bioresorbable materials also degrade and resorb through a process of bulk hydrolysis where the polymer chains of the synthetic material absorb water to break down the chemical structure to the various monomers which release harmful acids that can trigger elevated inflammation and a foreign body response such as seen with synthetic meshes commonly used in hernia abdominal wall repair and pelvic organ prolapse repair.
It is therefore an object of the invention to provide a fluid drainage or delivery device that addresses one or more of the abovementioned shortcomings, and/or at least to provide a useful alternative to existing devices.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally to provide a context for discussing features of the invention. Unless specifically stated otherwise, reference to such external documents or sources of information is not to be construed as an admission that such documents or such sources of information, in any jurisdiction, are prior art or form part of the common general knowledge in the art.
In a first aspect, the present invention provides a bioresorbable device for implantation at a treatment site in the body of a patient for draining fluid from the treatment site or delivering fluid to the treatment site. The device comprises a bioresorbable resilient truss for holding two tissue surfaces spaced apart, thereby defining a channel into which fluid from the treatment site can drain or from which fluid can be delivered to the treatment site, and a port in fluid communication with the one or more channels and being connectable to a source of negative pressure or positive pressure.
In an embodiment, the truss comprises a flexible elongate truss member. The truss may be curved and located along a wall of the channel.
In an embodiment, the truss member is substantially helical.
The truss may define the channel. For example, the outer diameter of a substantially cylindrical helical truss may correspond to the diameter of the channel. Or the width of a truss may correspond to the width of the channel. In an embodiment, the truss forms a flexible tube defining the channel. The tube may be substantially cylindrical or oval or elliptical or otherwise shaped. In an embodiment, the truss has a substantially circular cross-section in a resting, non-implanted state, and takes on an oval or elliptical cross section upon implantation in response to compressive forces acting on the truss, to define a channel with a correspondingly oval or elliptical cross-section.
The device may comprise a plurality of flexible elongate truss members. In one embodiment, a first one of the truss members is substantially helical with a first pitch length, and a second one of the truss members is substantially helical with a second pitch length. In an embodiment, the second pitch length is different to the first pitch length. For example, the first pitch length may be between about three to about five times the second pitch length, preferably about 4.5 times the second pitch length. Alternatively the first pitch length and the second pitch length may be the same, and the two respective truss members wound in opposite directions. The first and second truss members may be joined together and/or to bracing members at discrete points.
The channel may be circular in cross section, or non-circular, for example oval or elliptical.
The device may comprise two flexible elongate side truss members, each extending longitudinally along a side of the channel and joined at discrete points to the first and/or second truss members. The truss members may be joined by heat welding, stitching, or by adhesive, as examples. In an embodiment having an oval or elliptical cross sectional profile, the flexible elongate side truss members may be provided at on the minor axis of the cross section. In one embodiment, the device comprises two pairs of elongate side truss members, running along opposite sides of the truss.
The device may further comprise a flexible bioresorbable sheet, the sheet forming at least a portion of a wall of the channel. In an embodiment, the channel is formed between a surface of the flexible sheet and the surface of tissue or bone of the treatment site. For example, the sheet may be laid over an arch-type truss member. Alternatively, the flexible sheet may be wrapped around the truss, for example to enclose the truss. A plurality of apertures may be provided in the flexible sheet along a wall of the channel to permit fluid flow into the channel. The apertures may be provided as one or more rows of regularly spaced apertures, or irregularly arranged. The apertures may only be provided in selected portions of the device to selectively drain fluid from or deliver fluid to target areas of the treatment site.
In an embodiment, the device comprises two flexible bioresorbable sheets, wherein the channel is formed between facing surfaces of the two flexible sheets. The sheets may be stitched or adhered together along side seams. A plurality of apertures may be provided in one or both flexible sheets along a wall of the channel to permit fluid flow into the channel. The apertures may be provided as one or more rows of regularly spaced apertures, or irregularly arranged. The apertures may only be provided in selected portions of the device to selectively drain fluid from or deliver fluid to target areas of the treatment site.
In an embodiment, at least one truss member may comprise a length of thread or tape woven or sewn into or through at least one flexible sheet. For example, filament/thread sewn using a zig-zag stitch through one or more layers of flexible sheet. In an embodiment, the truss member(s) comprise suture.
In an embodiment, the or each flexible sheet comprises one or more layers of extracellular matrix (ECM) or polymeric material. The ECM may be formed from decellularised propria-submucosa of a ruminant forestomach. The ECM may contain a bioactive agent selected from the group comprising doxycycline, tetracyclines, silver, FGF-2, TGF-B, TGF-B2, BMR7, BMP-12, PDGF, IGF, collagen, elastin, fibronectin, and hyaluronan.
In an embodiment, the truss forms an elongate flexible tube defining the channel, and the device comprises one or more joiners holding at least a length of the flexible tube in a sinuous shape. Alternatively or additionally, the truss may define a plurality of channels into which fluid from the treatment site can drain or from which fluid can be delivered to the treatment site. For example the truss may define a primary channel and a plurality of secondary channels branching off the primary channel.
In an embodiment, the treatment site is a space between surfaces of muscle tissue, connective tissue or skin tissue that have been separated during surgery or as a result of trauma.
In an embodiment the treatment site is an exposed area of tissue, such as muscle or subcutaneous tissue, in an open surgical or tunnelled wound.
In an embodiment, the fluid to be delivered to the treatment site contains one or more nutrients or therapeutic agents for promoting wound healing.
In a second aspect, the present invention provides a system for draining fluid from a treatment site or delivering fluid to a treatment site in the body of a patient. The system comprises the device described above in relation to the first aspect, a conduit releasably coupled to either the port of the device or to a fluid impermeable dressing, a reservoir located external to the body of the patient, the reservoir in fluid communication with the conduit for receiving fluid from the conduit or delivering fluid to the conduit, and a source of pressure coupled to the conduit for delivering positive pressure or negative pressure to the device.
In an embodiment, the source of pressure is capable of delivering negative pressure to the device so that fluid is drained from the treatment site into the device and transferred through the conduit to the reservoir. The pressure may be applied continuously, or vary. For example the pressure may be applied intermittently, pulsed, or altered over the course of treatment.
In an embodiment, the source of pressure is capable of delivering positive pressure to the device so that fluid in the reservoir is transferred through the conduit into the device and to the treatment site. The pressure may be applied continuously, or vary. For example the pressure may be applied intermittently, pulsed, or altered over the course of treatment.
In an embodiment, the treatment site is an exposed area of tissue, such as muscle or subcutaneous tissue, in an open surgical or tunnelled wound.
In a third aspect, the present invention provides a method of draining fluid from a treatment site or delivering fluid to a treatment site in the body of a patient. The method comprises implanting the device described above in relation to the first aspect at the treatment site, coupling a conduit to the port of the device, the conduit being connected to a reservoir located external to the body of the patient for receiving fluid from the conduit or delivering fluid to the conduit, and delivering negative pressure to the device so that fluid is drained from the treatment site into the device and transferred through the conduit to the reservoir, or delivering positive pressure to the device so that fluid in the reservoir is transferred through the conduit into the device and to the treatment site. Optionally, a wound dressing may be applied to an incision near the treatment site, and negative pressure applied to the wound dressing, the wound dressing negative pressure supply being also coupled to the positive or negative pressure source. In an embodiment, the treatment site may be an exposed area of tissue, such as muscle or subcutaneous tissue, in an open surgical or tunnelled wound.
The term “bioresorbable” as used herein means able to be broken down and absorbed or remodelled by the body, and therefore does not need to be removed manually.
The term “treatment site” as used herein refers to a site in a human or animal body where surfaces of muscle tissue, connective tissue or skin tissue have been separated during surgery or as a result of trauma or removal.
The term “propria-submucosa” as used herein refers to the tissue structure formed by the blending of the lamina propria and submucosa in the forestomach of a ruminant.
The term “lamina propria” as used herein refers to the luminal portion of the propria-submucosa, which includes a dense layer of extracellular matrix.
The term “extracellular matrix” (ECM) as used herein refers to animal or human tissue that has been decellularised and provides a matrix for structural integrity and a framework for carrying other materials.
The term “decellularised” as used herein refers to the removal of cells and their related debris from a portion of a tissue or organ, for example, from ECM.
The term “polymeric material” as used herein refers to large molecules or macromolecules comprising many repeated subunits, and may be natural materials including, but not limited to, polypeptides and proteins (e.g. collagen), polysaccharides (e.g. alginate) and other biopolymers such as glycoproteins, or may be synthetic materials including, but not limited to polyglycolic acid, polylactic acid, P4HB (Poly-4-hydroxybutyrate), polylactic and polyglycolic acid copolymers, polycaprolactone and polydioxanone.
Various embodiments of the device and system of the present invention will now be described with reference to
The device 101 has a bioresorbable resilient truss 107 that, in use, holds two tissue surfaces 103, 104 spaced apart, thereby defining a channel 109 into which fluid from the treatment site can drain or from which fluid can be delivered to the treatment site. A port 111 in the form or an opening at one end of the truss 107 is in fluid communication with the channel 109 and allows for connection of the channel with a source of negative pressure or positive pressure 113. The two tissue surfaces 103, 104 need to be held apart because they would otherwise collapse together, particularly under application of negative or reduced pressure (vacuum) to assist with fluid drainage.
In some alternative embodiments the device 101 could be operably connected to one or more other devices, implanted at different respective sites for treating the respective sites with the same pressure source.
In some alternative embodiments the device could be in contact with another wound treatment device also connected to a source of negative or positive pressure.
d, 19 to 28b and 39a to 40c illustrate various exemplary embodiments of the resilient truss 107. The truss 107, 207, 307, etc. may define a single channel 109, 209, 309, etc. or a plurality of interconnected channels, for example in a branched structure. The truss 107, 207, 307, etc. is flexible in its longitudinal direction to allow the channel(s) to flex to substantially conform to the contours of the treatment site 102 and to reduce or prevent localised irritation or abrasion to the surrounding tissue. The truss is a three-dimensional structure with sufficient strength to hold the two tissue surfaces 103, 104 apart, at least at the time of implantation, without the truss buckling or the channel collapsing or kinking under movement or application of clinically appropriate levels of negative pressure. If the two tissue surfaces 103, 104 were to collapse together, fluid flow would be severely restricted and possibly blocked altogether.
As well as having sufficient cross-sectional strength to hold the tissue surfaces apart, the truss 107 is also resilient in its radial directions. This resilience allows some flexing of the channel walls under force to prevent or reduce damage to the tissue but ensures that the channel 109 will return to its original configuration when the force is removed. For example, if tissue movement results in increased pressure on the truss.
With reference to
The truss may have an ‘open’ form, where the truss member(s) lie only or predominantly along upper or lower and/or side portion of the channel, for example forming an arch-shaped truss 407, 507, 607, 707, 807 as shown in
Alternatively the truss may have a ‘closed’ form, in which the truss is tubular in nature, providing support to the tissue surfaces in all radial directions. For example, the embodiment of
The truss may comprise a plurality of helical truss members. For example,
In the embodiment shown, the truss 3507 further comprises two elongate side bracing members joined to both the first and second helical truss members. The elongate side members have a length substantially the same as the length of the channel or the portion of the channel along which they extend. In alternative embodiments, the truss may have more or fewer bracing members, and/or may have more than two helical members.
The first and second truss members 3515a, 3515b are bonded together and/or bonded to the bracing members 3516 at discrete points 3518 where the members overlap each other. This exemplary structure having multiple helical members bonded together advantageously allows a higher strength truss to be created using less truss material.
The truss comprises four elongate bracing truss members 3916, two at a top of the truss and two at a bottom of the truss as viewed in
This exemplary structure with non-circular cross sectional profile and bracing members on the minor axis, advantageously allows for the truss 3907 to have more flexibility in one direction while also preventing kinking or collapsing of the truss in the sections between the helical truss members 3915a, 3915b.
For both open and closed form trusses, the number and nature of any bracing members will depend on the strength characteristics of the constituent truss members, the number of truss members, their configuration, and the cross-sectional area of the channel, a truss having an open form may comprise one or more elongate truss members to brace the other truss members.
In some preferred embodiments of the invention, the channel has a cross sectional area of about 28 mm2. This may be provided by a cylindrical channel with diameter or maximum width of about 6 mm, or alternatively by an oval or elliptical channel. However, a range of cross sectional areas are possible, and different applications may require channels of different cross sections. For example, in alternative embodiments, the channel may have a cross sectional area in the range of about 3 mm2 to about 80 mm2, preferably about 12 mm2 to 50 mm2, i.e. in a cylindrical channel embodiment, a diameter or width in the range from approximately 1 mm to 10 mm, preferably about 4 mm to about 8 mm. The cross-sectional area may be constant or may vary. The larger cross-sectional area channel compared to conventional fluid drainage devices provides a more favourable, lower pressure drop over the length of the channel and is also favourable for preventing blockages.
The resilient truss also provides a more effective structure to provide a channel between two surfaces by reducing the overall mass of the synthetic material per unit length when compared to the existing prior art devices.
The truss also has a porous structure which permits free fluid exchange from the internal channel to the surrounding area for more effective passage of fluid when compared to the closed form nature of the existing prior art which is dependent on small diameter apertures/perforations to pass fluid into the channel. Synthetic bioresorbable polymers also typically release acid when they breakdown which can cause elevated levels of inflammation where existing prior art devices persist for longer given the thickness of the sections.
As a further alternative illustrated in
In some embodiments the truss 107 is implantable directly at the treatment site, such that the truss directly contacts surfaces of the treatment site. The surface of the treatment site would be formed from tissue (e.g. muscle tissue, connective tissue or skin) or bone of possibly a combination of tissue and bone. A wall or walls defining the channel is then formed by the tissue surfaces themselves, where they are held apart by the truss. The channels may be formed between the surface of one sheet of a flexible material and a surface of the treatment site.
Referring to
To secure the flexible sheet or sheets over or around the truss, the sheet or sheets may be stitched together along a seam at a side of the channel.
Referring now to
In embodiments with a single sheet wrapped around the truss, a plurality of apertures, for example arranged in one or more rows of apertures, may be provided in the flexible sheet. Where only a single row is provided, the apertures may be larger than for embodiments having two or more rows, to offer a similar rate of fluid flow into or out of the channel. For example,
Because the device is bioresorbable and does not need to be removed, the size and spacing of the channel wall apertures 2825, 2925 is not limited by the need to limit trauma to tissue on removal. Existing removable drains which have apertures must balance the need for fluid transfer through the wall apertures of the device, with the need to reduce patient trauma during removal. Thus, existing drain devices limit the size of channel apertures to minimise the in-growth of tissue through the aperture, as in-growth is associated with increased trauma on removal of the device and contributes to blockages in the device, this reduction in the size of the apertures reduces the effectiveness of such devices in draining fluid. In contrast, in the present device, the truss underlying the apertures reduces tissue in-growth into the channel that may contribute to blockages while allowing the ingress or expulsion of fluid through gaps between adjacent portions of truss members.
As mentioned above, the truss 103, 203, 303, etc. may define a single channel or a plurality of interconnected channels, for example as a branched structure. It will be appreciated that some devices of the invention will comprise many channels for fluid flow, for example 3, 4, 5, 6, 7, 8, 9, 10 or more channels, whereas some devices of the invention may comprise only 1 or 2 channels.
The device may optionally include bioresorbable webbing 1322, . . . , 2222 between adjacent channels to maintain the relative positions of the channels and to improve the ease of implanting the device or assist. The webbing 1322, . . . , 2222 may be provided by one or both of the flexible sheets 1319, . . . , 2219 and 1321, . . . , 2221 as in the embodiments shown in
Generally, the inclusion of webbing undesirably increases the surface area of the device and which can create a barrier to the apposition of opposing tissue faces within a dead space therefore preventing the healing and subsequent reconnection of previously separated tissue. To minimise the physiological impact of the webbing, apertures 1627, 1727 may be provided in the webs (see
In alternative embodiments, the device may be a single channel device 3401, 3801. The single channel device 3401, 3801 may be elongate and flexible such that a surgeon can bend and configure the device 3401, 3801 as desired to fit within the treatment site 3402. For example, the device may be bent back and forward on itself, in a sinuous shape as illustrated in
The single line shape also could work well within a minimally invasive surgical procedure such as a laparoscopic where it may be deployed following surgery as a prophylactic or retrospectively to treat a seroma or as a means to cyclically instil drugs to treat infections or diseases etc.
The single channel device may comprise webs or tabs 3822, for example between successive channel bends, to hold the channel in a desired configuration and improve ease of implanting the device as shown in
The type and size of device will be selected based on the characteristics of the treatment site. For example, a branched embodiment may be suitable for a treatment site having a relatively large surface area. In some instances, it will be desirable for the configured device to have a generally wide shape so that the channel or channels for fluid flow spread across the area of the treatment site to the greatest extent possible. In other instances, the shape of the sheets may be long and narrow, for example to lie just underneath a surgical incision line.
Optionally, the device may be temporarily held in its desired configuration by a removable positioning instrument or device that can adjust the shape of the device to suit the area of the treatment site while it is being implanted and secured in place.
Optionally, one or more channels or the device may be arranged so to provide one or more alternative flow paths in the case that a channel or the device becomes blocked.
The device has a port 111 in fluid communication with the channel or channels of the device, so that fluid that drains into any one of the channels will flow towards and out of the port 111. For a device having a branched structure such as those in
The port may be configured for location internally in a patient or for location externally, for example on the exterior surface of the patient's skin or otherwise the exterior of the patient's body close to a surgical opening in the body. In the case of an internally located port, when in use, the main structure of the device will be located at the treatment site and the port will be located internally within or alternatively near an edge of the treatment site, or conversely positioned at to a remote location elsewhere in the body. The port 111 may merely consist of an opening at the end of the truss or channel, for communication with a conduit 14 from the negative or positive pressure source 13. In some embodiments of the device, 2501, 2601, 3101, the truss 2507, 2670, 3107 extends beyond the flexible sheet or sheets, and for receipt by the conduit 2514, 2614, 3114 (see
Alternatively, the apparatus 3901 may comprise a portion 3946 of truss 3907 extending beyond the flexible sheet or sheets 3919 to be received by a conduit 3914 as shown in
As illustrated in
It will be appreciated that other methods of coupling the device to the supply conduit are appreciated and envisaged, including additional retention features. For example, an interior surface of the conduit could may be threaded or have protrusions/detents for additional engagement with the truss to prevent unintended disconnection. A secondary retention method may include utilising a loop of thread or suture passed down a lumen of the conduit and threaded through the interface of the truss members and the conduit to provide a secure connection which can be simply released by pulling on loop of thread to release the connection.
The flexible sheet or sheets may be cut away adjacent to the port as shown in
The device may comprise one or more features to secure the device relative to soft tissue.
An externally positioned port may have a similar form to those described above in relation to an internally positioned port. Advantageously, when the function of fluid drainage of fluid delivery is complete, the conduit can be decoupled from the externally positioned port, and the port can be inserted into the body through the surgical opening and the opening surgically closed. As the entire device is formed from bioresorbable materials, the port will then be absorbed or remodelled by the body along with the device over time. Alternatively, the port of the device may be cut off or otherwise removed from the device and the surgical opening then surgically closed.
The device described above is intended for use in a system for draining fluid from a treatment site or delivering fluid to a treatment site in the body of a patient. Exemplary systems are shown in
In some embodiments, the port 3411 may be coupled to an impermeable dressing 3433 located on the exterior surface of the skin 3406 which provides an airtight hermetic seal around the incision of the skin and an alternative means to which a conduit is releasably coupled to the dressing. One exemplary system is schematically illustrated in
With reference to
The source of pressure 3413 may be capable of delivering negative pressure to the device 3401 so that fluid is drained from the treatment site 3402 into the device 3401 and transferred through the conduit 3414 to the reservoir 3429, or may be capable of delivering positive pressure to the device so that fluid in the reservoir is transferred through the conduit into the device and to the treatment site. The fluid flow path is indicated in for the embodiments shown in the drawings by flow arrows F.
The source of pressure will typically be a pump for pumping fluid from the reservoir into the device 3401 for delivery to the treatment site or a vacuum pump 3413 for applying negative pressure to drain fluid from the treatment site 3402. The pump may be manually operated, for example using a squeeze bulb, or may be electronically controlled for more precise delivery of fluid to the site.
In a system where fluid is being delivered to the treatment site, the fluid to be delivered may contain one or more nutrients, Towable fluids' such as Thixotropic gels or highly viscous fluids that can still be transported via a conduit, cell-suspensions therapeutic agents for promoting wound healing. The device described herein may advantageously be customised to adjust the duration for which the device is functional in-situ for any given application. For example, by adjusting wall thicknesses, or the thickness or density of truss members.
In alternative embodiments, such as those devices having the truss and sheet arrangements of
The device of the invention is formed from bioresorbable materials. Typically, two types of bioresorbable material will be used, one for the flexible sheets and any webs and one for the truss.
In some embodiments of the invention, the flexible sheet(s) are formed from ECM. The ECM sheets are typically collagen-based biodegradable sheets comprising highly conserved collagens, glycoproteins, proteoglycans and glycosaminoglycans in their natural configuration and natural concentration. ECM can be obtained from various sources, for example, dermis pericardial or intestinal tissue harvested from animals raised for meat production, including pigs, cattle and sheep or other warm blooded vertebrates.
The ECM tissue suitable for use in the invention comprises naturally associated ECM proteins, glycoproteins and other factors that are found naturally within the ECM depending upon the source of the ECM. One source of ECM tissue is the forestomach tissue of a warm-blooded vertebrate. The ECM suitable for use in the invention may be in the form of sheets of mesh or sponge.
Forestomach tissue is a preferred source of ECM tissue for use in this invention. Suitable forestomach ECM typically comprises the propria-submucosa of the forestomach of a ruminant. In particular embodiments of the invention, the propria-submucosa is from the rumen, the reticulum or the omasum of the forestomach. These tissue scaffolds typically have a contoured luminal surface. In one embodiment, the ECM tissue contains decellularised tissue, including portions of the epithelium, basement membrane or tunica muscularis, and combinations thereof. The tissue may also comprise one or more fibrillar proteins, including but not limited to collagen I, collagen III or elastin, and combinations thereof. These sheets are known to vary in thickness and in definition depending upon the source of vertebrate species.
The method of preparing ECM tissues for use in accordance with this invention is described in U.S. Pat. No. 8,415,159.
In some embodiments of the invention, sheets of polymeric material may be used. The polymeric material may be in the form of sheet or mesh. Synthetic materials such as polyglycolic acid, polylactic acid and poliglecaprone-25 will provide additional strength in the short-term, but will resorb in the long term. Alternatively, the polymeric material may be a natural material, or derived from a natural material, such as a proteins (e.g. collagen), a polysaccharides (e.g. alginate), and a glycoprotein (e.g. fibronectins).
It will be understood that the truss members forming the truss will be formed from a material that has a degree of flexibility to allow the device to conform to the contours of the treatment site, and will have sufficient structural strength and integrity to hold the two surfaces apart and thereby allow channels to form. The structural integrity of this material and resulting shape will also provide a means for the fluid flow channel to be reinstated should the device be kinked or crushed in any circumstance. For example, the truss members may comprise a length of suture, thread, cord, or tape made from a bioresorbable material such as polyglycolic acid (PGA), polylactic acid (PLA), polyglycolic-polylactic copolymers, P4HB (Poly-4-hydroxybutyrate), polycaprolactone or polydioxanone.
Any desirable bioactive molecules can be incorporated into the ECM or polymeric material or the truss member material itself. Suitable molecules include for example, small molecules, peptides or proteins, or mixtures thereof. The bioactive materials may be endogenous to ECM or maybe materials that are incorporated into the ECM and/or polymeric material during or after the grafts manufacturing process. In some embodiments, two or more (e.g. 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) distinct bioactive molecules can be non-covalently incorporated into ECM or polymer. Bioactive molecules can be non-covalently incorporated into material either as suspensions, encapsulated particles, micro particles, and/or colloids, or as a mixture thereof. Bioactive molecules can be distributed between the layers of ECM/polymeric material. Bioactive materials can include, but are not limited to, proteins, growth factors, antimicrobials, and anti-inflammatories including doxycycline, tetracyclines, silver, FGF-2, TGF-B, TGF-B2, BMR7, BMP-12, PDGF, IGF, collagen, elastin, fibronectin, and hyaluronan.
The surgical placement of the device is best shown in
Alternatively the device could be placed at the bottom of an open wound and used in conjunction with a dressing.
The ability to controllably instil and dose flowable and cell-based fluids to treatment sites following surgery is desirable in many clinical procedures following the surgical excision of cancerous tissue or where ongoing infection is a concern. The ability to precisely control various parameters such as the dose concentration, contract time, dose volume and site at the treatment site also offers an advantage over existing drug eluting or dosed implant devices which often rely on the degradation properties of the material for a dosage profile.
Instillation of autologous or allogenic cell-based therapies containing either platelet rich plasma, stem cells, stromal cells, keratinocytes, lymphocytes, bone marrow aspirate, serum and dendritic cells could aid in the repair and healing of wounds.
For example, the instillation of intestinal stem cells could help in the treatment of inflammatory bowel disease, while the instillation of pancreatic islet cells following partial or complete a pancreatectomy could aid in the repair and regeneration of damage tissues.
The instillation of chemotherapeutic drugs could also aid in the localised treatment of cancerous cells that may not be operable, or could be used as an overall treatment plan following excision of cancerous tissue.
The management of a subcutaneous tissue under a closed surgical incision can be clinically challenging in procedures which involve a large amount of adipose (fat) tissue. Adipose tissue is known to possess poor mechanical strength in its ability to retain suture and the elevated distance between the skin and the underlying muscle can lead to the formation of a dead space that allows the collection of fluids post-surgery which can lead to later complications such as wound dehiscence and surgical site infections. The example given below demonstrates how this device may be utilised to eliminate the surgical dead space beneath a surgical incision.
The surgical placement of the device is best shown in cross-sectional views of
Topically applied wound treatment devices which apply negative pressure to the surface of a primary surgical incision have become widely adopted for the prevention of surgical complications such as wound dehiscence and surgical site infections. These topically applied devices primarily aid healing by providing a secondary mechanical retention to reduce the tensile force on the primary suture line and by covering and removing excess exudate from the skin to prevent maceration and infection.
While these devices have demonstrated effectiveness at supporting the healing of the skin incisions, they are unable to effectively manage the dead space of deeper subcutaneous tissues particularly those that have been subjected to a large amount of undermining, separation or excision which often require a greater amount of time to heal than compared to a skin incision. In these scenarios, a combined system of the implanted treatment device 3701 and a topically applied wound treatment device 3736 may be utilised to eliminate dead space at an internal treatment site while managing the healing of a surgical skin incision 3734.
The surgical placement of a combined topical and implanted treatment system is best shown in the cross-sectional views of
Once negative pressure or suction is applied to the implanted treatment device 3701 the fluid F from the treatment site is drawn towards the device 3701 reducing and closing the dead space within the subcutaneous tissue 3704 to create apposition 3739 of the two opposing faces of previously separated tissue 3704, as shown in
A schematic of a combined treatment system is additionally shown in
With reference to
In both figures the implanted treatment device 3401 is a single channel device arranged in a sinuous configuration to allow the device 3401 to effectively deliver treatment over a large area. However, other device types or configurations may be utilised.
One example of manufacturing the device truss component is described generally above in relation to
At this point, the entire assembly is placed into the oven at a temperature of about 120° C. for approximately 5 minutes to allow all the intersecting vertices 3518 of the truss members 3516, 3515a, 3515b to bond together. Once adequate bonds have has formed, the assembly is removed from the oven and allowed to cool before both clamps 3544 are removed and the central forming mandrel 3530 is removed to leave the device truss 3507 as a single resilient yet flexible and pliable component as shown in
In this example the second (outer) truss member 3515b is wound with a continuous pitch that differs to the pitch of the first truss member at a ratio of 3.5:1.
The truss members in this example comprise USP size #0 bioresorbable polydioxanone monofilament suture material which is approximately 0.4 mm in diameter, but this method could be used for any diameter of suture with any material type. The oven temperature and the time of heat application will vary for different embodiments, for example, depending on the size and material properties of the truss members, and the number of truss members. For this example, the choice of monofilament suture is made to provide the suitable rigidity required to form the resilient yet pliable final truss structure, but either monofilament or braided or any combination of the two types of filament could be used depending on the structure and truss properties required.
An alternative method of manufacturing the truss in a continuous process is given below. With reference to
As the first truss member 3615 is wound, heat is locally applied to a zone of the assembly to bond intersecting vertices 3618 of the truss members 3615, 3616. Once adequate heat has been applied, the formed truss 3607 is cooled and indexed off the central mandrel 53 as shown in
The ability to administer drugs and fluids to a targeted treatment site within the body has become an important tool within the field of medicine particularly for the treatment of pain, localised infections or diseases. While routine administration of drugs is common for many patients globally the length of treatment can widely vary from a short duration to patients with life dependency.
One aspect of the device disclosed herein is the ability to couple the implanted device to a source of treatment fluids such as antibiotic drugs, flowable gels, cell-based fluids and pain relief drugs for a prescribed contact time. A schematic representation for such a treatment system is best shown in
The implanted treatment device 3401 is also shown to contain several apertures 3425 in the channel walls to allow the passage of fluid out of the device, through the device surface 3419. The positioning of the channel apertures 3425 is particularly important for the controlled administration of drugs to the desired treatment site 3402. While the implanted treatment device 3401 is shown to have channel apertures 3425 along much of the length of the device 3401, the position and frequency of these apertures can be adjusted to suit the site of treatment 3402.
In this example the source of negative pressure 3413 could be operating in either a continuous, intermittent, constantly varying or discontinuous mode where the applied negative pressure could range from 0 mmHg to 200 mmHg or cycle between any prescribe levels during operation. The instillation of drugs can be administered by opening a valve on the treatment fluid reservoir 3437, or injecting fluids into the treatment reservoir 3437, where the source of negative pressure would draw the treatment fluid towards the source of negative pressure 3413. The time of which the drug is in contact with the treatment site can be controlled by the operation of negative pressure at the pressure source 3413, which could be stopped to hold the drug statically within the channels of the device 3401.
Alternatively the administration of drugs could be controlled by injecting or connecting the treatment fluid reservoir 3437 to a source of sterile saline or other fluid to purge the line clear of any treatment drugs.
Any reference to prior art documents in this specification is not to be considered an admission that such prior art is widely known or forms part of the common general knowledge in the field.
As used in this specification, the words “comprises”, “comprising”, and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean “including, but not limited to”.
Although the invention has been described by way of example, it should be appreciated that variations and modifications may be made without departing from the scope of the invention as defined in the claims. Furthermore, where known equivalents exist to specific features, such equivalents are incorporated as if specifically referred in this specification.
Filing Document | Filing Date | Country | Kind |
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PCT/NZ2018/050134 | 10/3/2018 | WO | 00 |
Number | Date | Country | |
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62679207 | Jun 2018 | US | |
62568914 | Oct 2017 | US |