Fat graft processing syringe absorbent and syringe incorporating same

Abstract

A syringe for withdrawing an aspirate including fat cells from a body includes a barrel having an inner wall, a filter for separating the fat cells from the aspirate extends within the barrel, an absorbent positioned between the filter and the barrel inner wall for absorbing aspirate that traversed the filter, and a plunger for longitudinal movement within the barrel. The plunger includes a gasket attached to a proximal end and the absorbent includes fibers and a majority of the fibers are oriented in a substantially radial direction relative a direction of longitudinal movement of the plunger.

Description

FAT GRAFT PROCESSING SYRINGE ABSORBENT AND SYRINGE INCORPORATING SAMEThis application claims the benefit of U.S. Provisional Patent Application No. 63 / 642,214, filed May 3, 2024, the disclosure of which is incorporated herein by reference.FIE D OF THE INVENTION

[0001] The invention generally relates to a syringe for harvesting, processing, and reintroducing a small volume fat graft into patients and, more specifically, to an absorbent for the syringe and methods of using the same.BACKGROUND OF THE INVENTION

[0002] The process of micro fat grafting involves the suction aspiration, e.g. liposuction, of small amounts of fat from a harvest site of a patient, and subsequent re-injection of the fat into a grafting site of the same patient. The aspirate is harvested from an area of the patient in which an excess of fat cells reside, such as the patient’s thighs, abdomen, or hips. The aspirate typically includes fat cells, local anesthetic, oil from ruptured fat cells, and blood. In order to deliver a high- quality fat cell graft, viable fat cells must be gently separated from the other components of the aspirate. Excess or rough processing of the fat cells can damage the viable cells. If the fat cells are damaged, they will not take and will die when re-introduced to the body leading to poor longterm results. Hence, the goal is to re-introduce or graft as many viable fat cells as possible and minimize the re-introduction of the non-viable cells and other components of the aspirate.

[0003] The most common micro fat grafting technique involves an initial liposuction of aspirate with a syringe and a harvesting cannula. The surgeon creates a vacuum inside the syringe which draws the aspirate through the cannula and into the barrel of the syringe. Although the aspirate could be directly re-injected into the grafting site, it is preferential to separate the fat cells from the remaining aspirate since only the fat cells are capable of maintaining viability in the grafting site. Therein are currently several methods for separating fat cells from the remaining aspirate for grafting including, processing the aspirate via centrifuge, filtering or washing the aspirate, using a washing vessel, and / or simply waiting for gravity to separate the fat cells from the remaining aspirate.

[0004] With most existing methods of fat cell harvesting, the fat cells must be removed from a harvesting container, processed, and transferred into one or more syringes for re-injection. Hence, these methods involve substantial handling of the fat cells and possibly generating trauma thereto. Even more, significant mechanical forces are applied to the fat cells with centrifugation and some of the known filtration methods which can lead to cellular damage. Transferring and processing the fat cells also requires significant time and exposes the fat cells to potential contamination during the open transfer process. More recent advancements in fat cell harvesting have provided more effective and efficient means of harvesting fat cells, separating viable fat cells from oil and fluid of the remaining aspirate in a gentle and timely manner, minimizing or eliminating vessel transfer, i.e., utilizing a closed system, and re-introducing viable fat cells back into the patient thereby minimizing the number of apoptotic cells in the fat graft.

[0005] Once such advancement described in U.S. Patent No. 11,724,036 to Kirn et al., teaches such a fully enclosed system for harvesting, processing, and re-introducing fat cells during a fat grafting procedure. This syringe 10 is generally shown in Figure 1 and includes a two component barrel 12 having a first portion 14 which is used to harvest an aspirate, including fat cells from a patient, and a second portion 16 which is used to process the aspirate. In the described embodiment, the first portion 14 is referred to as a proximal portion and the second portion 16 is referred to as a distal portion. When a harvest cannula (not shown) is attached to the syringe 10 and inserted into the patient, a plunger 18 can be withdrawn to generate a vacuum which suctions the aspirate from a harvest site of the patient. Once a desired amount of aspirate has been harvested, the cannula is removed from the patient and detached from the syringe 10 and processing of the fat graft initiated.

[0006] Processing of the fat graft involves withdrawing the syringe plunger 18 so that the harvested aspirate is drawn into a processing chamber 20, thus exposing the aspirate to an absorbent 22. The absorbent 22 is positioned between a filter 24 and an inner wall of the distal portion 16 of the syringe for absorbing the aspirate passing through the filter. The aspirate includes a fluid portion and a fat cells portion. The fluid portion of the aspirate is drawn through or traverses the filter 24 leaving the fat cells portion for reintroduction.

[0007] The absorbent 22 in the patented system is generally described as any material capable of retaining fluid, including a cotton, a super absorbent-embedded cotton, a superabsorbentmaterial, or a superabsorbent polymer. Even more, the absorbent 22 is described as a multicomponent absorbent including a first cotton fiber component that wicks and / or absorbs oils from ruptured fat cells. The cotton fibers are combed or straightened fibers that can soak up oil by letting it flow into channel-like spaces that form between the fibers relying on capillary action. A second fiber component includes fibers which wick and / or absorb aqueous fluids such as saline, blood, and local anesthetic, and a third component includes a material, such as a sodium polyacrylate or other superabsorbent material, for trapping or locking in the wicked fluids. In this prior art system, the absorbent 22 is positioned within the processing or absorbent chamber 20 defined in part by the distal portion 16 of the barrel 12 as shown in Figure 2.

[0008] In another embodiment described in the Kirn patent, the absorbent components may be situated in layers arranged and varied in either a vertical, a radial, or an angular pattern with respect to a central axis of the syringe 10. As shown in Figure 3, a first layer 26 may include the first and second fiber components for wicking oils and aqueous fluids, and a second layer 28 may include the material for locking in the wicked oil and fluid.

[0009] As shown in Figure 4, the absorbent may also be configured as a cartridge 30 in another embodiment and inserted into the chamber 20 as a unit during manufacture or at the time of use. The cartridge 30 may be stamped or otherwise formed and slid into the chamber around the filter 24. In this embodiment, the filter 24 extends within the chamber 20 and adjacent the absorbent 22. The filter 24 is described as a cotton gauze, a mesh filter, a fine mesh filter, a paper, an absorptive paper, a semipermeable membrane, and / or a perforated polymer sheet.

[0010] In a later filed PCT application (International Publication No. WO 2023 / 225310), Kirn further describes the filter 24 (shown in Figure 5) as being generally cylindrical in shape and forming a portion of a filter assembly 32. In the described embodiment, the filter 24 is an eighty mesh screen. The filter 24 may be a plastic polymer or metal and may utilize a broader range of mesh so long as the size of the openings are sufficient to limit, if not prevent, fat cells from traversing the filter. As further shown in Figure 5, the filter 24 forms a portion of the filter assembly 32. A first or proximal support 34 receives a first end of the filter 24, engages the syringe, as shown herein in Figure 1, to preclude (1) longitudinal and lateral movement of its proximal end and (2) aspirate drawn into the channel from entering the absorptive chamber 20 except through the filter 24. As further shown, a second support 36 receives a second end of the filter 24, engagesthe syringe limiting lateral movement of the filter, defines a ledge 38 supporting a gasket or firing 40, and engages a cap 42 trapping the sealing gasket 40 in position therebetween for preventing leakage along the plunger 18.

[0011] While the patented Kirn system and process has taught effective techniques for harvesting and reintroducing fat cells into a patient within a closed system, it is further desirable to reduce the overall processing time for each graft thereby reducing both procedure and operating room time. Accordingly, a need exists for a syringe capable of expediting the separation of the fluid portion of the aspirate from the fat cells portion and, as a result, reducing the overall processing time for each graft.SUMMARY OF THE INVENTION

[0012] In accordance with the purposes and benefits described herein, a syringe for withdrawing an aspirate including fat cells from a body is provided. The syringe may be broadly described as including a barrel having an inner wall, a filter for separating the fat cells from the aspirate extends within the barrel, an absorbent positioned between the filter and the barrel inner wall for absorbing aspirate that traversed the filter, and a plunger for longitudinal movement within the barrel, the plunger having a gasket attached to a proximal end of the plunger, wherein the absorbent includes fibers and a majority of the fibers are oriented in a substantially radial direction relative a central axis of the barrel.

[0013] In another possible embodiment, the absorbent includes a plurality of fabric annular discs. In yet another, the plurality of annular discs are substantially concentrically stacked. In still another, each of the plurality of annular discs includes a central aperture defined by an inner ring and the majority of the fibers oriented in a substantially radial direction extending from the inner ring.

[0014] In still yet another possible embodiment, the filter is a mesh screen. In another possible embodiment, the mesh screen is a made of stainless-steel. In one other possible embodiment, the mesh screen includes a plurality of apertures selected to generally be between 60 - 100 mesh.

[0015] In one other possible embodiment, the mesh screen is at least partially coated. In still another, the mesh screen is at least partially coated with a hydrophilic material to encourage flowof an aqueous component of the fluid component of the aspirate. In yet another, the mesh screen is at least partially coated with a lipophilic material to encourage flow of an oil component of the fluid component of the aspirate. In still one other possible embodiment, the mesh screen is partially coated with a hydrophilic material to encourage flow of an aqueous component of the fluid component of the aspirate and partially coated with a lipophilic material to encourage flow of an oil component of the fluid component of the aspirate. In yet still another possible embodiment, the mesh screen includes a flared end.

[0016] In another possible embodiment, the syringe further includes a projection extending from the barrel first portion for engaging the flared end.

[0017] In yet another possible embodiment, the syringe further includes a guide supported by the barrel first portion for engaging the flared end.

[0018] In still another possible embodiment, the barrel includes first and second portions and an inner diameter of an inner wall of the barrel first portion is substantially the same as an inner diameter of an inner wall of the filter.

[0019] In one other possible embodiment, the barrel first portion has an inner wall with a lesser inner diameter than an inner diameter of an inner wall of the barrel second portion.

[0020] In still yet another possible embodiment, the inner wall of the barrel second portion and the filter define an absorbing chamber wherein the filter resides.

[0021] In yet another possible embodiment, the inner wall of the first portion defines a notch for receiving a proximal end of the filter. In one other possible embodiment, the syringe further includes a ring that encases an end of the mesh screen. In another, the notch receives the ring. In still another, the ring sealingly engages at least the notch.

[0022] In another possible embodiment, the absorbent is a sheet of fabric folded back and forth in an accordion style. In still another, the folded sheet forms a substantially cylindrical shape.

[0023] In yet another possible embodiment, the cylindrically shaped folded sheet includes a first group of folded edges adjacent the filter and a second group of folded edges adjacent the barrel inner wall.

[0024] In still another possible embodiment, at least one slit is formed in at least one of the folded edges of the first group of folded edges.

[0025] In one other possible embodiment, the filter is a mesh screen. In another, the mesh screen is a made of stainless-steel. In yet another, the mesh screen includes a plurality of apertures selected to generally be between 60 - 100 mesh.

[0026] In another possible embodiment, the absorbent includes an absorbent layer positioned between fabric sheets. In still another possible embodiment, the absorbent layer is a fabric or a weave of fibers. In yet another, a first of the fabric sheets is adjacent the filter and a second of the fabric sheets is adjacent the barrel inner wall.

[0027] In yet still another possible embodiment, the plunger gasket includes a chamfer formed on a distal portion of the gasket.

[0028] In accordance with another aspect of the invention, a syringe for withdrawing an aspirate including fat cells from a body is provided. The syringe may be broadly described as including a barrel having an inner wall, a mesh screen filter for separating the fat cells from the aspirate extends within the barrel, an absorbent positioned between the filter and the barrel inner wall for absorbing aspirate that traversed the filter, and a plunger for longitudinal movement within the barrel, the plunger having a gasket attached to a proximal end of the plunger, wherein the absorbent includes a plurality of stacked fabric annular discs.

[0029] In one other possible embodiment, each of the fabric annular discs of the plurality of stacked fabric annular discs includes a central aperture defined by an inner ring and a majority of the fibers in the fabric annular discs is oriented in a substantially radial direction extending from the inner ring.

[0030] In accordance with another aspect of the invention, a syringe for withdrawing an aspirate including fat cells from a body is provided. The syringe may be broadly described as including a barrel having an inner wall, a mesh screen filter for separating the fat cells from the aspirate extends within the barrel, an absorbent positioned between the filter and the barrel inner wall for absorbing aspirate that traversed the filter, and a plunger for longitudinal movement withinthe barrel, the plunger having a gasket attached to a proximal end of the plunger, wherein the absorbent includes a sheet of fabric folded back and forth in an accordion style.

[0031] In another possible embodiment, the cylindrically folded sheet includes a first group of folded edges substantially adjacent to the mesh screen filter.

[0032] In still another possible embodiment, at least one slit is formed in at least one of the first group of folded edges.

[0033] In accordance with another aspect of the invention, a syringe for withdrawing an aspirate including fat cells from a body is provided. The syringe may be broadly described as including a barrel having first and second portions, the first portion having an inner wall having an diameter less than an inner diameter of an inner wall of the second portion, a mesh screen having an inner diameter substantially the same as the inner diameter of the inner wall of the first portion of the barrel extends within the barrel, a plunger for longitudinal movement within the barrel, the plunger having a gasket attached to a proximal end forming a seal with an inner wall of the mesh screen and the inner wall of the barrel first portion, and an absorbent including fibers and at least partially contacting the mesh screen for drawing a fluid portion of the aspirate through the mesh screen in a substantially radial direction relative a direction of longitudinal movement of the plunger.

[0034] In accordance with another aspect of the invention, a syringe for withdrawing an aspirate including fat cells from a body is provided. The syringe may be broadly described as including a barrel having an inner wall, a mesh screen sized to prevent fat cells from traversing the mesh screen extends within the barrel, an absorbent positioned between the mesh screen and the barrel inner wall for absorbing aspirate that traversed the mesh screen, and a plunger for longitudinal movement within the barrel, wherein the absorbent includes a stack of discs to draw the aspirate that traversed the mesh screen in a substantially radial direction relative a direction of longitudinal movement of the plunger.

[0035] In another aspect of the invention, a method of securing fat cells for fat grafting using a syringe includes the steps of retracting a plunger from a first position to a second position in order to draw an aspirate from a harvest site of a body into a barrel of the syringe, further retracting the plunger from the second position in order to draw a wash solution into the barrel of the syringe,exposing the combined aspirate and wash solution to an absorbent including a plurality of stacked annular discs for absorbing a fluid portion of the aspirate, moving the plunger toward the first position such that a remaining portion of the aspirate is no longer exposed to the absorbent, and repeating the exposing and moving steps.

[0036] In another possible embodiment, the plurality of stacked annular discs are substantially concentrically stacked.

[0037] In yet another possible embodiment, each of the plurality of stacked annular discs includes a central aperture defined by an inner ring and the majority of the fibers oriented in a substantially radial direction extending from the inner ring.

[0038] In still another possible embodiment, the filter is a mesh screen.

[0039] In yet still another possible embodiment, the absorbent is a sheet of fabric folded back and forth in an accordion style.

[0040] In one other possible embodiment, the folded sheet forms a substantially cylindrical shape.

[0041] In another possible embodiment, the cylindrically shaped folded sheet includes a first group of folded edges adjacent the filter and a second group of folded edges adjacent the barrel inner wall.

[0042] In still another possible embodiment, at least one slit is formed in at least one of the folded edges of the first group of folded edges.

[0043] In yet another possible embodiment, the absorbent includes an absorbent layer positioned between fabric sheets.

[0044] In another possible embodiment, the absorbent layer is a fabric or a weave of fibers.

[0045] In still yet another possible embodiment, a first of the fabric sheets is adjacent the filter and a second of the fabric sheets is adjacent the barrel inner wall.

[0046] In another possible embodiment, the further retracting step includes retracting the plunger to a third position and the exposing step includes further retracting the plunger from the third position where the combined aspirate and wash solution are exposed to the absorbent.

[0047] In still another possible embodiment, the syringe includes a filter and the absorbent is supported between the filter and a first portion of an inner wall of the barrel.

[0048] In one other possible embodiment, the a gasket is supported at an end of the plunger and sealing engages a second portion of the inner wall of the barrel and engages an inner wall of the filter.

[0049] In another possible embodiment, the plunger gasket includes a chamfer formed on a distal portion of the gasket.

[0050] In still yet another possible embodiment, the plunger gasket dislodges any unabsorbed aspirate during the step of moving the plunger toward the first position such that a remaining portion of the aspirate is no longer exposed to the absorbent.

[0051] In the following description, there are shown and described several preferred embodiments of a syringe for withdrawing an aspirate including fat cells from a body and related methods of securing fat cells for fat grafting using the syringe. As it should be realized, the various syringes and methods are capable of other, different embodiments and their several details are capable of modification in various, obvious aspects all without departing from the syringes and methods as set forth and described in the following claims. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive.BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0052] The accompanying drawing figures incorporated herein and forming a part of the specification, illustrate several aspects of the invention and related methods and together with the description serve to explain certain principles thereof. In the drawing figures:

[0053] Figure 1 is a perspective view of a prior art syringe for withdrawing aspirate from a body for micro fat grafting with a partially transparent barrel;

[0054] Figure 2 is a section cut end view of the prior art syringe and a multi-component absorbent;

[0055] Figure 3 is a section cut end view of the prior art syringe with the multi-component absorbent formed in layers;

[0056] Figure 4 is a section cut end view of another embodiment of the prior art syringe wherein the absorbent is formed into a cartridge;

[0057] Figure 5 is a perspective view of a filter assembly used with the prior art syringe;

[0058] Figure 6 is a section cut partial plan view of an absorbent disc illustrating a direction of fibers therein;

[0059] Figure 7 is a section cut plan view of a portion of the syringe showing a plunger withdrawn into the distal end adjacent an absorbent for aspirate processing;

[0060] Figure 8 is perspective view of an absorbent disc used in one embodiment to form the absorbent shown in Figures 6 and 7;

[0061] Figure 9 is a perspective view of another embodiment of an absorbent;

[0062] Figure 10 is a top view of the other embodiment of the absorbent showing an accordion or folding style used to form the absorbent; and

[0063] Figure 11 is an yet another embodiment of an absorbent including an absorbent layer sandwiched between fabric layers and indicating orientation of fibers within the absorbent layer;

[0064] Figure 12 is a section cut plan view of a portion of the syringe showing an interface between the mesh screen and the proximal portion of the syringe and a chamfered plunger gasket for assisting with the transition between the proximal and distal portions of the syringe; and

[0065] Figure 13 is a section cut plan view of a portion of the syringe showing an interface between the mesh screen and the proximal portion of the syringe wherein an end portion of the mesh screen is flared outward and engages a projection extending from the proximal portion.

[0066] Reference will now be made in detail to the present invention and embodiments of the syringe for harvesting, processing, and re-introducing small volume fat grafts into patients, and absorbents used therein, examples of which are illustrated in the accompanying drawing figures, wherein like numerals are used to represent like elements.DETAILED DESCRIPTION

[0067] A syringe 50 for withdrawing an aspirate including fat cells from a body for micro fat grafting uses a mesh screen filter 52 and absorbent material 54 in combination to separate and contain an unwanted fluid portion of an aspirate from a desired fat cells portion. In doing so, a high quality fat graft can be obtained in a closed system in an expedited manner. In order to achieve such an expedited process, one or more features (e.g., the type, quality, quantity, and positioning) of the absorbent material or absorbent 54 within the syringe 50 should be carefully considered. Specifically, the absorbent 54 should provide enough fluid capacity to remove most, if not all, of the unwanted or remaining fluid portion of the aspirate drawn into a processing chamber 48 and hinder the absorbed remaining fluid portion from reentering the processing chamber during the micro fat grafting process.

[0068] In one described embodiment shown in Figure 6, a plurality of absorbent discs 56 are stacked atop one another and, collectively, form the absorbent 54. An exemplary absorbent disc 56 is shown in Figure 7 and a horizontal orientation of fibers 58 within an absorbent disk is illustrated in Figure 8. As shown in Figure 8, the horizontal fibers 58 generally extend radially from a cut surface 60 which forms an inner ring of the disc 56. In this described embodiment, the remaining fluid is drawn through the mesh screen 52 and into the absorbent 54. The horizontal alignment of the fibers 58 allows the remaining fluid to traverse radially from a first end adjacent the cut surface 60 and mesh screen 52 toward a second end adjacent an inner wall 62 of the syringe 50.

[0069] In order to achieve the desired quick and efficient removal of the remaining fluid portion of the aspirate, the orientation of fibers which at least partially make up the absorbent 54 must be considered. If a majority of the fibers in an absorbent are oriented in a vertical position when viewing a syringe from top to bottom, then absorption will mainly occur in that same direction at the expense of absorption in a radial direction. In other words, radial penetration intothe absorbent will be limited. For this reason, it is desirable to have a majority of the fibers within the absorbent 54 oriented in a substantially radial direction relative a central axis of the barrel and plunger of the syringe.

[0070] The orientation of a majority of fibers within an absorbent 54 in a radial direction is achieved in the described embodiment through the utilization of cutting and stacking profiles used to create a stack of absorbent discs 56 which collectively form the absorbent 54. Figure 6 illustrates a plurality of absorbent discs 60 stacked atop one another to form an absorbent 54. The utilization of stacked discs 60 ensures at least a portion of fibers 58 in each disc is oriented in a radial direction. The number of fibers 58 oriented in a radial direction within an absorbent 54 can be further improved by weaving of the fibers during the production process.

[0071] Because most weaving and manufacturing procedures for fiber-based absorbents known in the art create a fabric-like product in which the fibers run parallel to a face or surface of the fabric, it is necessary to use proper cutting and stacking techniques to properly orient the fibers. In order to create a tightly packed absorbent stack, the absorbent fabric can be cut into into annular discs that are then stacked upon one another. In this manner, the absorbent fabric can still occupy a maximum amount of space within an absorbing chamber, while also orienting fibers in a desired direction. In the described embodiment, an absorbing chamber 64 is partially defined by the mesh screen filter 52 and an inner wall 62 of the syringe 50 as shown in Figure 6.

[0072] In another embodiment illustrated in Figure 9, an absorbent 66 includes an absorbent fabric sheet 68 that is folded back and forth in an accordion style (similar to the fabric within an oil filter). This approach, again, orients at least a majority of fibers within the sheet 68 in a radial direction. As shown in Figure 10, the remaining fluid portion drawn through the mesh screen filter 52 is drawn radially from an inner folded edge 70 of the absorbent 66 adjacent the mesh screen filter toward an outer folded edge 72 adjacent the syringe inner wall 62. In other embodiments, one or more slits 74 may be made along the inner folded edges or ends 70 of the absorbent 66 as shown in Figure 9. The one or more slits 74 may be made in one or more of the inner folded edges 70 to allow for the remaining fluid portion of aspirate to improve contact with the absorbent fibers and may extend partially along or along a majority of a length of the inner folded edges 70.

[0073] In one additional embodiment, an absorbent can be made utilizing known techniques to mechanically weave or blow fibers into a mold that is shaped to conform to an absorbing chamber such as chamber 64. This approach results in an absorbent having fibers oriented in a substantially radial direction without the need for mechanical cutting or manipulation.

[0074] It should be noted that absorbents made from a non-woven material still benefit from the above-described design processes. While such absorbents may be non-woven and have seemingly random placement of fibers therein, the sheet design of such absorbents dictates that the average orientation of the fibers remains parallel to a face of the fabric. This is due at least in part to the length of each fiber being longer than a thickness of the fabric sheet. In this way, a fiber cannot have its full length perpendicular to the face and must have some portion nonperpendicular, i.e., radially extending. The same cannot be said for the parallel direction as a fiber’s entire length can be oriented in this direction. Through this constraint, if an average fiber orientation is taken across an entire fabric sheet, the average orientation must be closer to parallel than to perpendicular and, as such, orienting the sheet as stated in the above paragraphs (e.g., cutting and stacking, or folding) will provide the desired orientation of fibers in a substantially radial direction.

[0075] In another embodiment of an absorbent 76 shown in Figure 11, the absorbent 76 includes a “sandwich” construction in which an absorbent fabric or weave of fibers forms an absorbent layer 78 positioned between fabric sheets 80. In the described embodiment, the outer fabric sheets 80 have sufficient mechanical strength to support the absorbent layer 78. This allows the absorbent layer 78 to be formed using a less sturdy or mechanically strong absorbent material while allowing the absorbent to be manufactured in an desired configuration. For example, arrowed lines, designated reference numeral 82 and overlaying the absorbent layer 78, indicate an orientation of the fibers within the absorbent layer as being substantially radially extending.

[0076] While this approach allows for absorbents to be mass produced in an economical and easy to use form, it also creates a scenario wherein fluid must first pass through the fabric sheets 80 to come into contact with the absorbent layer 78. For applications in which time or performance is a less important factor, this method of absorption is a reasonable option but it inherently decreases performance and overall efficiency. For this reason, it is preferable to utilize the same design consideration noted above when using these types of fabrics. Specifically, for example,cutting the sandwich style absorbent 76 into annular discs or folding it into an accordion style pattern increases direct access to the absorbent layer 78 for the remaining fluid component of the aspirate.

[0077] Due to the nature of most absorbents, i.e., fiber based and pliable, a mesh screen filter is used in the described embodiments to separate the fat cells portion from the remaining fluid portion of the absorbent. The mesh screen filter 52 confines the absorbent 54 and also allows for a plunger 84 to effectively and efficiently move the fat cells portion, including the viable fat cells, from the processing chamber 48 of the syringe 50 once sufficient absorption of the remaining fluid component has been achieved. In one embodiment, a stainless-steel mesh screen filter 52 is used due to its rigidity and biocompatibility while a plastic or composite mesh screen filter may be used in other embodiments. In addition, the hole sizing of the mesh screen filter 52 is selected to generally be between 60 - 100 mesh which range is selected as optimal.

[0078] For reference, mesh sizing indicates a number of openings in a mesh screen per linear inch. The lower limit on the mesh sizing is important because too small a sizing does not allow for enough of the remaining fluid portion (e.g., medical fluids and oils) to pass through the mesh screen in a desired amount of time leading to a graft of decreased quality. At smaller mesh sizes, capillary action and surface tension begin to play an increasing role in interfering with desired flow through the orifices of the mesh screen filter. On the other end of the sizing, the larger limit on the mesh size relates to the potential loss of viable fat cells during the processing stage. If the orifices are too large, viable fat cells would be allowed to traverse the mesh screen filter or become stuck in the screen and would not be utilized in the grafting process when the plunger 84 is returned to the proximal portion of the syringe 50. For example, a mesh sizing exceeding 100 mesh has been determined to yield no material improvement in fat cell graft quality, but does yield a material decrease in fat cell graft volume.

[0079] Within the embodiments described herein that utilize a mesh screen filter 52 as the filter, it is desirable to have the plunger 84 and plunger gasket 86 mate perfectly with the mesh screen filter. This arrangement which eliminates gaps between the plunger gasket 86 and mesh screen filter 52 allows the plunger gasket to wipe an inner surface of the mesh screen filter. This is typically accomplished after absorption has occurred when the plunger is advanced in a proximal direction. Additionally, the arrangement prevents viable fat cells within the fat cells portion of theaspirate remaining in the processing chamber 48 from leaking past the plunger gasket 86 and being lost for purposes of grafting.

[0080] The above-described arrangement between the plunger gasket 86 and the mesh screen filter 52 can result in certain challenges. For example, as the plunger gasket 86 moves longitudinally within the processing chamber 48, strands of wire can be exposed at a point where the mesh screen filter 52 is terminated. Such exposed strands of wire can puncture, snag, or otherwise damage the plunger gasket 86 as it moves within and through the processing chamber 48. Doing so can cause the plunger gasket 86 to dislodge from the plunger 84, cause the mesh screen filter 52 to be pulled back and collapse, or create a hole in the plunger gasket rendering it inoperable due to no longer being sealable against filter 52 and / or the proximal portion of the syringe 50.

[0081] It should be noted that all three of these possibilities can limit, if not eliminate, the usefulness of the syringe 50. To avoid such a result, an end of the mesh screen filter 52 may be encased in a ring 88 as partially shown in Figure 12. This can be achieved, for example, either by molding a plastic (or other known moldable materials) ring 88 over the mesh screen filter 52 or gluing such a ring onto the mesh screen filter. In this way, the plunger gasket 86 can move safely past the interface with minimal danger of damage. In another embodiment, the mesh screen filter 52 may be integrally molded into the syringe 50 to achieve the same result.

[0082] In another embodiment shown in Figure 13, a mesh screen filter 90 is configured with an outwardly flared proximal end 92. As shown, the flared proximal end 92 engages a guide 94 correspondingly flared for engaging and directing the flared proximal end toward a resting position. In the resting position, the flared proximal end 92 is supported by a projection 96 extending from the proximal portion 98 of the syringe. In this manner, smooth passage of the plunger gasket (not shown) is ensured without the need for a ring or molding.

[0083] In an added aspect in each of the described embodiments, the plunger gasket 86 may be formed with a chamfer 100 on a distal portion 102. Standard plunger gaskets do not include a chamfer and can be more difficult to move backwards against a non-uniform surface. The chamfer 100 may be integrally molded into the plunger gasket 86 and can take the shape of a chamfer, a filet, or a combination thereof, or a similarly angled shape.

[0084] In using the syringe embodiments described herein, a puncture incision is made by the user in a desired harvest site of a patient’s body. A harvesting device, such as a cannula, is connected to the syringe 50 by means of a Luer lock fitting, or other fitting, extending from the syringe as is known in the art. The cannula is inserted into the body; the user withdraws the plunger 84 of the syringe 50 creating a vacuum pressure in the syringe and moves the cannula in a manner familiar to those skilled in the art. The vacuum pressure draws an aspirate into a harvest chamber 104 of the syringe 50. As the procedure continues, the user further withdraws the plunger 84 to maintain a consistent, low vacuum. Graduations printed on the syringe 50 reveal an amount of aspirate collected. This process continues until a desired quantity of aspirate has been harvested or the harvesting chamber 104 is substantially full. The cannula is subsequently removed from the patient’s body and detached from the syringe 50, and processing of the fat graft initiated.

[0085] Although not required, the user may then connect the syringe 50 to an external wash solution source (not shown). Preferably, the wash solution source is connected to the syringe 50 by means of the above-described Luer lock fitting in order to preserve a sterile environment provided by the closed system. Once connected, the user may further retracts the plunger 84 drawing a wash solution into the harvesting chamber 104 of the syringe 50. In the described embodiment, a wash solution of Lactated Ringers or Normal Saline at a volume of 20% of the aspirate volume, i.e., 25 mL of aspirate + 5 mL of wash solution, is utilized. The aspirate and the wash solution are combined in the harvest chamber 104 and then drawn, via further movement of the plunger 84, into the processing chamber 48. Once there, the syringe 50 may be agitated by rolling, rotating, and / or shaking for a period of time. In the described embodiment, a period of one minute is deemed sufficient although any period of time may be utilized albeit with varying effectiveness.

[0086] The aspirate, including any of the remaining fluid portion and the fat cells portion remaining in the processing chamber 48, is then returned to the harvest chamber 104 and a second specified quantity (e.g., again about 25% of the initial aspirate) of a wash solution is added using the plunger 84. The step of returning unabsorbed aspirate to the harvest chamber 104 provides an added benefit of wiping the mesh screen filter 52 with the plunger gasket 86 and minimizing any obstruction within the mesh screen filter. In other words, physical contact between the plunger gasket 86 and the inner wall of the mesh screen filter 52 during the step of moving the plunger 84proximally within the syringe 50 dislodges or breaks away any non-liquid components of the unabsorbed aspirate from the mesh screen filter. This ensures that the mesh screen filter is substantially unobstructed and open allowing additional unabsorbed fluid to traverse the mesh screen filter 52 during the subsequent step(s). With the mesh screen filter 52 wiped by the plunger gasket 86, the remaining aspirate is subsequently drawn back into the processing chamber 48 through movement of the plunger 84 and agitated for a second period of time during which additional absorption occurs. Again, one minute is deemed sufficient although other periods may be utilized in accordance with the described invention.

[0087] Once the second period ends and with the syringe 50 held upright, the user moves the plunger 84 proximally within the syringe thereby pushing the fat cells component into the harvest chamber 104 expelling any remaining air. The same cannula used for harvesting the aspirate, a different one, a hypodermic needle, or other re-insertion device (not shown) may then be reattached to the fitting. The re-insertion device is inserted into the patient’s body at the graft site. The plunger 84 is then pushed further forward expelling the processed fat graft from the harvest chamber 104, through the cannula, and into the patient’s body. In an alternate embodiment, the processed graft may be pushed out into another container, or syringe(s), in an open or a closed transfer process. The described syringes are intended for discard after a single use.

[0088] The foregoing has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Obvious modifications and variations are possible in light of the above teachings. For example, the mesh screen filter 52 may be coated with various coatings to decrease surface tension and encourage flow of the remaining fluid portion of the aspirate across the mesh screen. In a further alternate embodiment, the mesh screen filter 52 may be partially coated with one or more of the abovereferenced materials. For illustration purposes, one half of the mesh screen filter may be coated with a hydrophilic material to encourage flow of an aqueous component of the remaining fluid portion, and the other half could be coated with a lipophilic material to encourage flow of an oil component of the remaining fluid portion. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.

Claims

WHAT IS CLAIMED:

1. A syringe for withdrawing an aspirate including fat cells from a body, comprising: a barrel having an inner wall; a filter for separating the fat cells from the aspirate extends within the barrel; an absorbent positioned between the filter and the barrel inner wall for absorbing aspirate that traversed the filter; and a plunger for longitudinal movement within the barrel, the plunger having a gasket attached to a proximal end of the plunger, wherein the absorbent includes fibers and a majority of the fibers are oriented in a substantially radial direction relative a central axis of the barrel.

2. The syringe for withdrawing an aspirate including fat cells from a body of claim 1, wherein the absorbent includes a plurality of fabric annular discs.

3. The syringe for withdrawing an aspirate including fat cells from a body of claim 2, wherein the plurality of annular discs are substantially concentrically stacked.

4. The syringe for withdrawing an aspirate including fat cells from a body of claim 1 , wherein each of the plurality of annular discs includes a central aperture defined by an inner ring and the majority of the fibers oriented in a substantially radial direction extending from the inner ring.

5. The syringe for withdrawing an aspirate including fat cells from a body of claim 1, wherein the filter is a mesh screen.

6. The syringe for withdrawing an aspirate including fat cells from a body of claim 5, wherein the mesh screen is a made of stainless-steel.

7. The syringe for withdrawing an aspirate including fat cells from a body of claim 5, wherein the mesh screen includes a plurality of apertures selected to generally be between 60 - 100 mesh.

8. The syringe for withdrawing an aspirate including fat cells from a body of claim 5, wherein the mesh screen is at least partially coated.

9. The syringe for withdrawing an aspirate including fat cells from a body of claim 8, wherein the mesh screen is at least partially coated with a hydrophilic material to encourage flow of an aqueous component of the fluid component of the aspirate.

10. The syringe for withdrawing an aspirate including fat cells from a body of claim 8, wherein the mesh screen is at least partially coated with a lipophilic material to encourage flow of an oil component of the fluid component of the aspirate.

11. The syringe for withdrawing an aspirate including fat cells from a body of claim 8, wherein the mesh screen is partially coated with a hydrophilic material to encourage flow of an aqueous component of the fluid component of the aspirate and partially coated with a lipophilic material to encourage flow of an oil component of the fluid component of the aspirate.

12. The syringe for withdrawing an aspirate including fat cells from a body of claim 5, wherein the mesh screen includes a flared end.

13. The syringe for withdrawing an aspirate including fat cells from a body of claim 12, further comprising a projection extending from the barrel first portion for engaging the flared end.

14. The syringe for withdrawing an aspirate including fat cells from a body of claim 12, further comprising a guide supported by the barrel first portion for engaging the flared end.

15. The syringe for withdrawing an aspirate including fat cells from a body of claim 1, wherein the barrel includes first and second portions and an inner diameter of an inner wall of the barrel first portion is substantially the same as an inner diameter of an inner wall of the filter.

16. The syringe for withdrawing an aspirate including fat cells from a body of claim 15, wherein the barrel first portion has an inner wall with a lesser inner diameter than an inner diameter of an inner wall of the barrel second portion.

17. The syringe for withdrawing an aspirate including fat cells from a body of claim 15, wherein the inner wall of the barrel second portion and the filter define an absorbing chamber wherein the filter resides.

18. The syringe for withdrawing an aspirate including fat cells from a body of claim 15, wherein the inner wall of the first portion defines a notch for receiving a proximal end of the filter.

19. The syringe for withdrawing an aspirate including fat cells from a body of claim 18, further comprising a ring that encases an end of the mesh screen.

20. The syringe for withdrawing an aspirate including fat cells from a body of claim 19, wherein the notch receives the ring.

21. The syringe for withdrawing an aspirate including fat cells from a body of claim 20, wherein the ring sealingly engages at least the notch.

22. The syringe for withdrawing an aspirate including fat cells from a body of claim 1, wherein the absorbent is a sheet of fabric folded back and forth in an accordion style.

23. The syringe for withdrawing an aspirate including fat cells from a body of claim 22, wherein the folded sheet forms a substantially cylindrical shape.

24. The syringe for withdrawing an aspirate including fat cells from a body of claim 23, wherein the cylindrically shaped folded sheet includes a first group of folded edges adjacent the filter and a second group of folded edges adjacent the barrel inner wall.

25. The syringe for withdrawing an aspirate including fat cells from a body of claim 24, wherein at least one slit is formed in at least one of the folded edges of the first group of folded edges.

26. The syringe for withdrawing an aspirate including fat cells from a body of claim 22, wherein the filter is a mesh screen.

27. The syringe for withdrawing an aspirate including fat cells from a body of claim 26, wherein the mesh screen is a made of stainless-steel.

28. The syringe for withdrawing an aspirate including fat cells from a body of claim 26, wherein the mesh screen includes a plurality of apertures selected to generally be between 60 - 100 mesh.

29. The syringe for withdrawing an aspirate including fat cells from a body of claim 26, wherein the mesh screen is at least partially coated.

30. The syringe for withdrawing an aspirate including fat cells from a body of claim 29, wherein the mesh screen is at least partially coated with a hydrophilic material to encourage flow of an aqueous component of the fluid component of the aspirate.

31. The syringe for withdrawing an aspirate including fat cells from a body of claim 29, wherein the mesh screen is at least partially coated with a lipophilic material to encourage flow of an oil component of the fluid component of the aspirate.

32. The syringe for withdrawing an aspirate including fat cells from a body of claim 29, wherein the mesh screen is partially coated with a hydrophilic material to encourage flow of an aqueous component of the fluid component of the aspirate and partially coated with a lipophilic material to encourage flow of an oil component of the fluid component of the aspirate.

33. The syringe for withdrawing an aspirate including fat cells from a body of claim 26, wherein the mesh screen includes a flared end.

34. The syringe for withdrawing an aspirate including fat cells from a body of claim 33, further comprising a projection extending from the barrel first portion for engaging the flared end.

35. The syringe for withdrawing an aspirate including fat cells from a body of claim 33, further comprising a guide supported by the barrel first portion for engaging the flared end.

36. The syringe for withdrawing an aspirate including fat cells from a body of claim 22, wherein the barrel includes first and second portions and an inner diameter of an inner wall of the barrel first portion is substantially the same as an inner diameter of an inner wall of the filter.

37. The syringe for withdrawing an aspirate including fat cells from a body of claim 36, wherein the barrel first portion has an inner wall with a lesser inner diameter than an inner diameter of an inner wall of the barrel second portion.

38. The syringe for withdrawing an aspirate including fat cells from a body of claim 36, wherein the inner wall of the barrel second portion and the filter define an absorbing chamber wherein the filter resides.

39. The syringe for withdrawing an aspirate including fat cells from a body of claim 36, wherein the inner wall of the first portion defines a notch for receiving a proximal end of the filter.

40. The syringe for withdrawing an aspirate including fat cells from a body of claim 39, further comprising a ring that encases an end of the mesh screen.

41. The syringe for withdrawing an aspirate including fat cells from a body of claim 40, wherein the notch receives the ring.

42. The syringe for withdrawing an aspirate including fat cells from a body of claim 41, wherein the ring sealingly engages at least the notch.

43. The syringe for withdrawing an aspirate including fat cells from a body of claim 1 , wherein the absorbent includes an absorbent layer positioned between fabric sheets.

44. The syringe for withdrawing an aspirate including fat cells from a body of claim 43, wherein the absorbent layer is a fabric or a weave of fibers.

45. The syringe for withdrawing an aspirate including fat cells from a body of claim 43, wherein a first of the fabric sheets is adjacent the filter and a second of the fabric sheets is adjacent the barrel inner wall.

46. The syringe for withdrawing an aspirate including fat cells from a body of claim 1, wherein the plunger gasket includes a chamfer formed on a distal portion of the gasket.

47. A syringe for withdrawing an aspirate including fat cells from a body, comprising: a barrel having an inner wall; a mesh screen filter for separating the fat cells from the aspirate extends within the barrel; an absorbent positioned between the filter and the barrel inner wall for absorbing aspirate that traversed the filter; anda plunger for longitudinal movement within the barrel, the plunger having a gasket attached to a proximal end of the plunger, wherein the absorbent includes a plurality of stacked fabric annular discs.

48. The syringe for withdrawing an aspirate including fat cells from a body of claim 47, wherein each of the fabric annular discs of the plurality of stacked fabric annular discs includes a central aperture defined by an inner ring and a majority of the fibers in the fabric annular discs is oriented in a substantially radial direction extending from the inner ring.

49. A syringe for withdrawing an aspirate including fat cells from a body, comprising: a barrel having an inner wall; a mesh screen filter for separating the fat cells from the aspirate extends within the barrel; an absorbent positioned between the filter and the barrel inner wall for absorbing aspirate that traversed the filter; and a plunger for longitudinal movement within the barrel, the plunger having a gasket attached to a proximal end of the plunger, wherein the absorbent includes a sheet of fabric folded back and forth in an accordion style.

50. The syringe for withdrawing an aspirate including fat cells from a body of claim 49, wherein the cylindrically folded sheet includes a first group of folded edges substantially adjacent to the mesh screen filter.

51. The syringe for withdrawing an aspirate including fat cells from a body of claim 50, wherein at least one slit is formed in at least one of the first group of folded edges.

52. A syringe for withdrawing an aspirate including fat cells from a body, comprising: a barrel having first and second portions, the first portion having an inner wall having an diameter less than an inner diameter of an inner wall of the second portion; a mesh screen having an inner diameter substantially the same as the inner diameter of the inner wall of the first portion of the barrel extends within the barrel; a plunger for longitudinal movement within the barrel, the plunger having a gasket attached to a proximal end forming a seal with an inner wall of the mesh screen and the inner wall of the barrel first portion; andan absorbent including fibers and at least partially contacting the mesh screen for drawing a fluid portion of the aspirate through the mesh screen in a substantially radial direction relative a direction of longitudinal movement of the plunger.

53. A syringe for withdrawing an aspirate including fat cells from a body, comprising: a barrel having an inner wall; a mesh screen sized to prevent fat cells from traversing the mesh screen extends within the barrel; an absorbent positioned between the mesh screen and the barrel inner wall for absorbing aspirate that traversed the mesh screen; and a plunger for longitudinal movement within the barrel, wherein the absorbent includes a stack of discs to draw the aspirate that traversed the mesh screen in a substantially radial direction relative a direction of longitudinal movement of the plunger.

54. The syringe for withdrawing an aspirate including fat cells from a body of any of the claims 47-53, the mesh screen is a made of stainless-steel.

55. The syringe for withdrawing an aspirate including fat cells from a body of claim 54, wherein the mesh screen includes a plurality of apertures selected to generally be between 60 - 100 mesh.

56. The syringe for withdrawing an aspirate including fat cells from a body of claim 54, wherein the mesh screen is at least partially coated.

57. The syringe for withdrawing an aspirate including fat cells from a body of claim 56, wherein the mesh screen is at least partially coated with a hydrophilic material to encourage flow of an aqueous component of the fluid component of the aspirate.

58. The syringe for withdrawing an aspirate including fat cells from a body of claim 56, wherein the mesh screen is at least partially coated with a lipophilic material to encourage flow of an oil component of the fluid component of the aspirate.

59. The syringe for withdrawing an aspirate including fat cells from a body of claim 56, wherein the mesh screen is partially coated with a hydrophilic material to encourage flow of anaqueous component of the fluid component of the aspirate and partially coated with a lipophilic material to encourage flow of an oil component of the fluid component of the aspirate.

60. The syringe for withdrawing an aspirate including fat cells from a body of claim 54, wherein the mesh screen includes a flared end.

61. The syringe for withdrawing an aspirate including fat cells from a body of claim 60, further comprising a projection extending from the barrel first portion for engaging the flared end.

62. The syringe for withdrawing an aspirate including fat cells from a body of claim 60, further comprising a guide supported by the barrel first portion for engaging the flared end.

63. The syringe for withdrawing an aspirate including fat cells from a body of any of the claims 47-53, wherein the barrel includes first and second portions and an inner diameter of an inner wall of the barrel first portion is substantially the same as an inner diameter of an inner wall of the filter.

64. The syringe for withdrawing an aspirate including fat cells from a body of claim 63, wherein the barrel first portion has an inner wall with a lesser inner diameter than an inner diameter of an inner wall of the barrel second portion.

65. The syringe for withdrawing an aspirate including fat cells from a body of claim 63, wherein the inner wall of the barrel second portion and the filter define an absorbing chamber wherein the filter resides.

66. The syringe for withdrawing an aspirate including fat cells from a body of claim 63, wherein the inner wall of the first portion defines a notch for receiving a proximal end of the filter.

67. The syringe for withdrawing an aspirate including fat cells from a body of any of the claims 47-53, further comprising a ring that encases an end of the mesh screen.

68. The syringe for withdrawing an aspirate including fat cells from a body of claim 67, wherein the notch receives the ring.

69. The syringe for withdrawing an aspirate including fat cells from a body of claim 67, wherein the ring sealingly engages at least the notch.

70. The syringe for withdrawing an aspirate including fat cells from a body of any of the claims 47-53, wherein the mesh screen is a made of stainless-steel.

71. The syringe for withdrawing an aspirate including fat cells from a body of claim 70, wherein the mesh screen includes a plurality of apertures selected to generally be between 60 - 100 mesh.

72. The syringe for withdrawing an aspirate including fat cells from a body of claim of any of the claims 47-53, wherein the plunger gasket includes a chamfer formed on a distal portion of the gasket.

73. A method of securing fat cells for fat grafting using a syringe, comprising the steps of retracting a plunger from a first position to a second position in order to draw an aspirate from a harvest site of a body into a barrel of the syringe; further retracting the plunger from the second position in order to draw a wash solution into the barrel of the syringe; exposing the combined aspirate and wash solution to an absorbent for absorbing a fluid portion of the aspirate; moving the plunger toward the first position such that a remaining portion of the aspirate is no longer exposed to the absorbent; and repeating the exposing and moving steps.

74. The method of securing fat cells for fat grafting using a syringe of claim 28, wherein the further retracting step includes retracting the plunger to a third position and the exposing step includes further retracting the plunger from the third position where the combined aspirate and wash solution are exposed to the absorbent.

75. The method of securing fat cells for fat grafting using a syringe of claim 29, wherein the syringe includes a filter and the absorbent is supported between the filter and a first portion of an inner wall of the barrel.

76. The method of securing fat cells for fat grafting using a syringe of claim 30, wherein a gasket is supported at an end of the plunger and sealing engages a second portion of the inner wall of the barrel and engages an inner wall of the filter.

77. The method of securing fat cells for fat grafting using a syringe of claim 31, wherein the plunger gasket dislodges any unabsorbed aspirate during the step of moving the plunger toward the first position such that a remaining portion of the aspirate is no longer exposed to the absorbent.

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