Syringe for treating fat grafts and related methods

Abstract

A syringe for drawing aspirant from a body for microfat grafting has a barrel, a first barrel section having an inner wall diameter smaller than the inner diameter of the second section. A filter for separating fat cells from the aspirant extends into the second section of the barrel. An absorbent is located between the filter and the second section inner wall and absorbs aspirant passing through the filter. A plunger moving within the barrel along the first section inner wall and the filter has a gasket that forms a seal with the first section inner wall and the inner wall of the filter. Proximal and distal supports engage the filter and the barrel. In another embodiment, the filter has a flared end that engages the barrel. The invention also provides a method for obtaining fat cells for microfat grafting using the syringe.

Description

[Technical field]

[0001] This application has a filing date of May 20, 2022, and claims priority to U.S. Provisional Patent Application No. 63 / 344,314, the disclosure of which is incorporated herein by reference.

[0002] SUMMARY OF THE DISCLOSURE The present invention relates generally to a syringe for harvesting, processing and reintroducing small volumes of fat grafts into a patient. [Background technology]

[0003] In the case of micro fat grafting, a small amount of fat is aspirated from a patient's harvest site by suction aspiration, such as liposuction or other known techniques, and then the fat is reinjected into the same patient at a transplant site. Fat is harvested from areas of the patient where excess fat is present, such as the patient's thighs, abdomen, or buttocks. The aspirated fat generally contains fat cells, local anesthetic, oil from dehiscent fat cells, and blood. To obtain a high volume of fat cell graft, it is necessary to reasonably separate the live fat cells from the other components of the aspirated fat. Excessive or rough handling of the fat cells will cause damage to the live cells. Damage to the fat cells can result in necrosis and cell death after reinjection into the body, leading to poor long-term outcomes. Thus, the goal is to reintroduce or transplant as many live fat cells as possible and minimize the reintroduction of non-live and other components of the aspirated fat.

[0004] The most common microfat grafting procedure begins with liposuction using a syringe and collection cannula. The surgeon creates a vacuum inside the syringe, drawing the fat into the cannula and into the syringe barrel. Although the fat can be directly reinjected into the transplant site, it is preferable to separate the fat cells from the remaining fat, as only fat cells can remain viable at the transplant site. Currently, there are several methods to separate fat cells from the remaining fat for transplantation, including fat processing by centrifugation, fat filtering or washing using a washing vessel, and / or simple gravity separation of the fat cells from the remaining fat.

[0005] Many existing methods for harvesting fat cells require the removal of the fat cells from a harvesting container, processing the fat cells, and then transferring and re-injecting them into one or more syringes. Thus, these methods involve substantial processing of the fat cells, which may be traumatic. Furthermore, centrifugation and some known filtration methods apply significant mechanical forces to the fat cells, resulting in cell damage. Additionally, the transfer and processing of fat cells requires significant time, and open transfer exposes the fat cells to contamination. Thus, there is a need to effectively and efficiently harvest fat cells, separate live fat cells from residual lipoaspirate oils and fluids in a natural and timely manner, minimize or eliminate container changes, i.e., utilize a closed system, and minimize the number of apoptotic cells in the graft by re-injecting live fat cells back into the patient.

[0006] The following description shows and describes several embodiments of a syringe for aspirating fat from a human body for performing microfat grafting, and a corresponding method for immobilizing fat cells for performing microfat grafting using the syringe. It should be noted that the syringe and the corresponding method can be implemented in other different embodiments and can be modified in various obvious ways without departing from the assembly as recited in the claims. That is, the accompanying drawings and description are illustrative in nature and not intended to be limiting. Summary of the Invention

[0007] In accordance with the objects and advantages described herein, a syringe for harvesting fat from a human body and performing microfat grafting is described. The syringe can be broadly defined as having a barrel with a first portion and a second portion. The first barrel portion has an inner wall having a diameter smaller than the diameter of the inner wall of the second portion. The syringe further includes a filter extending into the second portion of the barrel for separating fat cells from the harvest, an adsorbent positioned between the filter and the inner wall of the second portion for adsorbing the harvest that permeates the filter, and a plunger moving longitudinally within the barrel along the inner wall of the first portion and the filter. The plunger also includes a gasket attached to a distal end of the plunger and forming a seal with the inner wall of the first portion at a first position and the inner wall of the filter at a second position.

[0008] A second aspect of the present invention relates to a syringe for aspirating fat from a human body for microfat grafting. The syringe may be broadly defined as having a barrel with a first portion and a second portion. The first barrel portion has an inner wall having a diameter smaller than the diameter of the inner wall of the second portion. The syringe further includes a filter extending into the second portion of the barrel for separating fat cells from the harvest, an adsorbent positioned between the filter and the inner wall of the second portion for adsorbing the harvest that permeates the filter, and a plunger moving longitudinally within the barrel along the inner wall of the first portion and the filter. Also in this embodiment, the plunger includes a gasket attached to a distal end of the plunger and forming a seal with the inner wall of the first portion in the first position. Furthermore, the inner diameter of the inner wall of the first portion and the inner diameter of the inner wall of the filter are substantially the same.

[0009] In another possible embodiment, the gasket sealingly engages the first portion of the barrel in a first position where the plunger is fully inserted into the barrel, in a second position where the plunger is retracted to the distal end of the first portion of the barrel, and any position in between.

[0010] In yet another possible embodiment, the inner wall of the second barrel section defines a notch that receives the proximal end of the filter.

[0011] In one alternative embodiment, the inner diameter of the notch is substantially the same as the diameter of the outer wall of the proximal end of the filter.

[0012] In another possible embodiment, the notch is positioned so that the distal end of the first portion of the barrel abuts the proximal end of the filter.

[0013] In yet another possible embodiment, the proximal end of the filter is flared outwardly.

[0014] In another possible embodiment, the syringe further includes a second gasket that sealingly engages the notch and the proximal end of the filter.

[0015] In one alternative embodiment, the distal end of the filter is flared outwardly.

[0016] In yet another possible embodiment, the filter has a proximal support.

[0017] In yet another possible embodiment, a proximal support receives the proximal end of the filter.

[0018] In another possible embodiment, the inner diameter of the notch is substantially the same as the diameter of the outer wall of the proximal support.

[0019] In yet another possible embodiment, the notch is positioned such that the first portion of the barrel abuts the proximal support at its distal end.

[0020] Moreover, in one or more possible embodiments, the proximal support sealingly engages at least the notch.

[0021] In yet another possible embodiment, the proximal support is at least one of rubber, polytetrafluoroethylene, fluorosilicone, and polyurethane.

[0022] In another possible embodiment, the exterior wall of the filter and the interior wall of the second portion of the barrel at least partially define a chamber in which the adsorbent resides.

[0023] In yet another possible embodiment, the syringe further includes a cap that engages the distal end of the barrel.

[0024] In one alternative embodiment, the cap further defines a chamber in which the adsorbent resides.

[0025] In yet another possible embodiment, the filter has a distal support that defines a central opening through which the plunger extends.

[0026] In another possible embodiment, a distal support receives the distal end of the filter.

[0027] In one alternative embodiment, the distal support includes a disk defining a central opening and having a radial outer edge.

[0028] In another possible embodiment, the inner diameter of the second portion of the barrel is substantially the same as the outer diameter of the radially outer edge of the distal support.

[0029] In yet another possible embodiment, the diameter of the central opening is smaller than the inner diameter of the filter forming the proximally facing projection such that the distal end of the filter abuts the face of the proximally facing ledge.

[0030] In yet another possible embodiment, the distal support further comprises an annular ring.

[0031] In yet another possible embodiment, the annular ring extends distally from the disc.

[0032] In one alternative embodiment, the inner diameter of the annular ring is greater than the diameter of the central opening that forms the distally facing projection on the disk.

[0033] In another possible embodiment, the distal face of the annular ring engages the cap to prevent longitudinal movement of the filter.

[0034] In yet another possible embodiment, the annular ring is at least one of a rubber ring, a polytetrafluoroethylene ring, a fluorosilicone ring, and a polyurethane ring.

[0035] In yet another possible embodiment, the interior of the filter defines a second channel, and the exterior of the filter and the interior wall of the second barrel section at least partially define a chamber within which the absorbent material resides.

[0036] In yet another possible embodiment, the second channel and the chamber are in continuous fluid communication as the plunger is retracted to any position between (1) a second position in which the plunger is retracted to the distal end of the first portion of the barrel, and (2) a third position in which the plunger is retracted to either (a) the distal end of the second portion of the barrel or (b) the distal end of the second portion of the barrel.

[0037] In one alternative embodiment, the gasket contacts the inner filter wall around the entire circumference of the inner filter wall.

[0038] In another possible embodiment, the filter is a plastic filter or a metal filter, hi yet another possible embodiment, the filter is a mesh.

[0039] In yet another possible embodiment, the filter is secured in a cylindrical shape by one or more welds.

[0040] In yet another possible embodiment, the syringe has a second filter extending into the chamber and positioned between the outer wall of the filter and the absorbent material.

[0041] In yet another possible embodiment, the second filter is selected from the group consisting of cotton gauze, a mesh filter, a fine mesh filter, paper, or an absorbent paper.

[0042] In one alternative embodiment, the absorbent material is cotton. In another alternative embodiment, the absorbent material is superabsorbent embedded cotton. In yet another alternative embodiment, the absorbent material comprises fibers.

[0043] In another possible embodiment, at least a first portion of the fibers absorbs oil by capillary action, and in yet another possible embodiment, at least a second portion of the fibers absorbs aqueous fluids by capillary action.

[0044] In yet another possible embodiment, the absorbent material comprises a superabsorbent material, hi yet another possible embodiment, the superabsorbent material is a superabsorbent polymer.

[0045] In one alternative embodiment, the absorbent has at least a first layer of fibers and a second layer of superabsorbent material. In another alternative embodiment, the absorbent has intimately bonded fibers and superabsorbent material.

[0046] In yet another possible embodiment, at least a first portion of the fibers absorbs oil by capillary action, and in yet another possible embodiment, at least a second portion of the fibers absorbs aqueous fluids by capillary action.

[0047] In another possible embodiment, the second filter and the absorbent material form a cartridge.

[0048] In yet another possible embodiment, the cartridge is generally cylindrical and is positioned over the filter.

[0049] In yet another possible embodiment, the syringe further includes at least one stopper formed on the plunger that engages a seal carried by the barrel to produce a tactile change in plunger movement.

[0050] In yet another possible embodiment, a seal is supported at the distal end of the second portion of the barrel to prevent leakage along the plunger. In another possible embodiment, the seal is supported by a distal support.

[0051] Another aspect of the present invention relates to a method for obtaining fat cells from a body for microfat grafting using a syringe, the method comprising: retracting the plunger having a gasket attached to a proximal end of the plunger from a first position in which the gasket engages an inner wall of a first portion of the syringe barrel to aspirate bodily fluid or other absorbent or aspirate fluid from a sample site in the body into the first portion of the barrel; further retracting the plunger to a second position to expose the body fluid to the filter and absorbent material and absorb a portion of the body fluid, wherein the gasket engages an inner wall of the filter in the second position; and The method includes moving the plunger to a first position such that unabsorbed portions of the bodily fluid are not exposed to the absorbent material.

[0052] In yet another possible embodiment, the inside diameter of the inner wall of the first portion of the barrel is smaller than the inside diameter of the second portion of the barrel.

[0053] In another possible embodiment, the inner diameter of the inner wall of the first portion of the barrel is substantially the same as the inner diameter of the inner wall of the filter.

[0054] In yet another possible embodiment, the transferring step includes returning the unabsorbed portion of the bodily fluid to the implantation site in the body.

[0055] In another possible embodiment, the method further comprises the step of adding irrigation solution to the bodily fluid aspirated in the retracting step by retracting the plunger from the first position to a first intermediate position.

[0056] In yet another possible embodiment, the method further comprises the step of adding irrigation solution to the unabsorbed portion of the bodily fluid by again retracting the plunger from the first intermediate position to the second intermediate position.

[0057] In another possible embodiment, the method further comprises the step of retracting the plunger along the filter to a second position to expose an unabsorbed portion of the mixture of body fluid and irrigation solution to the filter and absorbent material.

[0058] In yet another possible embodiment, the method includes moving the plunger to the first position at least one minute after retracting the plunger to the second position.

[0059] Hereinafter, several preferred embodiments of a syringe for aspirating body fluid from a body for microfat cell transplantation and a corresponding method for obtaining fat cells for microfat cell transplantation using the syringe will be illustrated and described. Note that the various syringes and methods can be implemented in different and distinct ways, and the details can be implemented in obvious configurations without departing from the syringes and methods described in the claims. In other words, the accompanying drawings and the description in this specification are for illustrative purposes only and are not intended to be limiting. [Brief description of the drawings]

[0060] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the syringe and method, and together with the following description should be read to explain the principles of the invention. [Figure 1] FIG. 1 is a perspective view of a syringe for aspirating fluid from the body for microfat grafting, with a portion of the barrel made transparent. [Diagram 2] FIG. 2 is a perspective view of the syringe with the barrel, absorbent, O-ring, and a portion of the filter assembly shown in cross section. [Diagram 3] FIG. 3 is a perspective view showing the filter assembly. [Figure 4]FIG. 4 is a cutaway end view of the syringe. [Diagram 5] FIG. 5 is a cutaway and partial end view of an alternative embodiment of a filter assembly. [Figure 6] FIG. 6 is a cutaway end view of yet another embodiment of a filter assembly. [Figure 7] FIG. 7 is a perspective view showing an alternative filter assembly.

[0061] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the syringe and associated methods are described in detail below, examples of which are illustrated in the accompanying drawings, in which like reference numerals refer to like elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] Referring to FIGURE 1, there is shown a syringe 10 for aspirating bodily fluids from a harvest site on the human body for microfat grafting. The syringe 10 has a fluid fitting 12 located at the proximal end of a barrel 14 that conforms to industry standard medical syringes. In this embodiment, the fluid fitting 12 is a male Luer-Lok connector designed to mate with a female Luer-Lok fitting. A fat harvesting cannula, hypodermic needle, liposuction cannula or other extraction device (not shown) is connected to the fluid fitting 12 when aspirating bodily fluids.

[0063] In the embodiment being described, the barrel 14 has a first portion 16 and a second portion 18. The first portion 16 has a smaller overall diameter than the second portion 18. As shown, a filter 20 extends longitudinally within the second portion 18 of the barrel 14. More specifically, and in the best mode as shown in FIG. 2, the inner diameter of the first channel that is entirely formed by the inner wall 24 of the first portion 16 of the barrel 14 is substantially the same as the inner diameter of the second channel that is formed by the filter 20.

[0064] As further shown in FIG. 2, the plunger 26 moves longitudinally through the first and second channels defined by the inner wall 24 of the first portion 16 of the barrel 14 and the filter 20, with a gasket 28 attached to the proximal end of the plunger forming a seal against the inner wall and the filter. As known to those skilled in the art, retraction of the plunger 26 in either or both of the channels creates a vacuum, which allows bodily fluid to be extracted from the body through the extractor and into the channel(s). That is, as the plunger 26 retracts from the first position, bodily fluid is drawn from the collection site in the body into the barrel 14 of the syringe 10. In this embodiment, the plunger 26 is fully inserted into the syringe 10 in the first position and retracted to the second position such that the gasket 28 abuts the distal end of the first portion of the barrel 16. In other embodiments, an external device or attachment device can be utilized to retract and / or lock the plunger into a desired position.

[0065] As shown in Figure 3, filter 20 is generally cylindrical and forms part of filter assembly 30. In this embodiment, filter 20 is an 80 mesh screen. Filter 20 may be made of a plastic polymer or metal. In this embodiment, 80 mesh is used, however, a wide range of mesh numbers can be selected for the opening size, as long as the mesh number is sufficient to restrict the passage of fat cells through the filter without inhibiting separation of the fat cells from the remaining body fluid.

[0066] When formed into a cylindrical shape, the filter 20 has sufficient rigidity to form the inner walls of the secondary channel and absorbent chamber 32. Advantageously, the filter 20 can be used to minimize the distance between the secondary channel through which bodily fluids are drawn and the absorbent material 34 located within chamber 32. Minimizing this distance can provide a significant, if not maximum, absorption of bodily fluids over previously known devices utilizing sleeve and / or shutter devices.

[0067] Additionally, the filter 20 reduces the overall amount of implant material required by eliminating gaps between the channels and the absorbent 34 where fluid can accumulate. Such gaps may be created by adding structures designed to control absorption and / or support the absorbent. Finally, the apertures or fenestrations in the filter 20 are evenly distributed along the entire filter, allowing full utilization of the absorbent or absorbent material 34. In other words, absorption occurs along the entire absorbent material 34 and does not create gaps due to non-porous structure(s) such as the sleeve and / or shutter device. When fluid contacts the absorbent material 34, a portion of the fluid, including blood, aqueous fluids such as anesthetics and saline, and oil, wicks through the filter and out of the fluid and is absorbed into the absorbent material.

[0068] In this embodiment, the filter 20 and the second portion 18 of the barrel 14 collectively define an absorbent chamber 32. A cap 36 and seal 38 (shown in FIG. 2) are supported on the distal end of the barrel 14 to prevent leakage along the plunger 26 and further define the chamber 32. The chamber 32 in which the absorbent material 34 is located is in fluid communication with the second channel at least along the length of the filter 20. As shown in FIG. 1, the formed chamber 32 extends along substantially the entire length of the second portion 18 of the barrel 14.

[0069] The absorbent material 34 can simply be any fluid capable of holding a fluid. For example, the absorbent material 34 can include a cotton, a super absorbent-embedded cotton, a superabsorbent material, or a superabsorbent polymer. In this embodiment, the absorbent material 34 is a homogenous, multi-component absorbent material, as shown in FIG. 4.

[0070] The multi-component absorbent material 34 contains fibers that wick and / or absorb oil from open fat cells by capillary action. Examples of such fibers include combed or carded cotton fibers, which wick oil by flowing into channel-like spaces formed between the fibers by capillary action. Furthermore, cotton fibers have both the ability to absorb oil by simply attaching to the fibers and wicking into the fibers. The second fiber component contains fibers that wick and / or absorb aqueous fluids, such as saline, blood, and local anesthetics, by capillary action, and the third component contains a material that traps or fixes the fluid wicked by capillary action. Examples of such materials include sodium polyacrylate and other superabsorbent materials known to those skilled in the art. All three components, or any two or more of the combined components, may be configured to maximize effectiveness.

[0071] In other embodiments, the absorbent components can be arranged in layers in a variety of perpendicular, radial, or angular patterns relative to the central axis of the syringe 10. As shown in Figure 5, a first layer can have first and second fibrous components that wick oil and aqueous fluids, and a second layer 42 can have a material that traps the absorbed oil and fluids.

[0072] As shown in FIG. 6, the absorbent material may be used in the form of a cartridge 44 in another embodiment, which may be inserted into the chamber 32 as a unit during manufacture or during use. The cartridge 44 may be formed, such as by stamping, and may be slid over the filter 20 and inserted into the chamber. In this embodiment, a filter 46 is utilized to prevent live fat cells from migrating from the channel into the chamber 32. The filter 46 extends into the chamber 32 and is located between the filter 20 and the absorbent material 34. The filter 46 may be, but is not limited to, cotton gauze, a mesh filter, a fine mesh filter, paper, absorbent paper, a semi-permeable membrane, and / or a porous polymer sheet. It is noted that a filter similar to the filter 46 may be utilized in non-cartridge embodiments to prevent fat cells from migrating through the filter 20 into the absorbent material chamber 32. Additionally, a color indicator may be utilized in any of these embodiments to indicate to the user that a sufficient amount of fluid has been absorbed. Such an indicator may be visually visible through at least a transparent or translucent portion of the syringe barrel 14.

[0073] Continuing with reference to FIG. 3, filter 20 forms part of filter assembly 30. A first (support portion 48) or proximal support portion 48 receives a first end of filter 20. As best seen in FIG. 2, proximal support portion 48 is generally annular in shape. A notch 50 defined by barrel 14 is shaped to receive proximal support portion 48. Once engaged, filter 20 cannot move within barrel 14, nor can its proximal end move laterally. Furthermore, bodily fluid captured in the first channel cannot enter absorbent chamber 32 from anywhere other than filter 20. To ensure this sealing effect, proximal support portion 48 can be constructed of a suitable material (e.g., hard rubber) and a gasket or O-ring (not shown) can be added as is known in the art.

[0074] 2 and 3, a second support 52, also generally annular in shape, receives the second end of the filter 20. A support surface 54 extends radially and engages the second portion 18 of the barrel 14 to limit lateral movement of the filter therein. A circular ring 56 extends longitudinally from the support surface 54 and defines a ledge 58 that supports the gasket or O-ring 38 within the circular ring 56. In this embodiment, the second support 52 engages the cap 36 to trap the sealing gasket 38 in a position therebetween so that no leakage occurs along the plunger 26.

[0075] First support 48 and second support 52 also hold the mesh of filter 20 in a cylindrical configuration. Additionally, a small flange (not shown) located distally on first support 48 and proximally on second support 52 engages and protects the raw ends of filter 20, as well as acting as a stop for the assembly and ensuring a smooth transition while plunger gasket 28 moves from the inner wall 24 of barrel first section 16 into the interior of the filter.

[0076] In another embodiment, shown in Figure 7, filter 72 is formed into a cylindrical shape using laser welding 74 or similar known techniques. In this configuration, first support 48 and second support 52 do not need to maintain a cylindrical shape. Additionally, proximal and distal ends 76 and 78 of filter 72 are flared outwardly to smooth the transition for plunger gasket 28. These flared ends 76 and 78 fit into the same recess in barrel 14 required to accommodate filter 20.

[0077] Specifically, the proximal end 76 is received within the notch 50 defined by the barrel 14. Once engaged, the filter 72 cannot move longitudinally within the barrel 14, and the proximal end 76 cannot move laterally. Furthermore, bodily fluid drawn into the first channel cannot flow into the absorbent chamber 32 except through the filter 72. To ensure this sealing effect, a gasket or O-ring (not shown) can be provided, as is known in the art. Similarly, the distal end 78 engages the second portion 18 of the barrel 14 to limit lateral movement of the filter 72 within the barrel. The cap 36 in this embodiment can be provided with a gasket or O-ring to prevent leakage along the plunger 26, as is known in the art.

[0078] As previously described, in all embodiments, as the plunger 26 is retracted from the first position, bodily fluid is drawn into the barrel 14 of the syringe 10 from a collection site in the body. Upon retraction beyond the second position, the bodily fluid is exposed to the absorbent material 34, which absorbs a first portion of the bodily fluid while leaving a second portion of the bodily fluid, primarily comprising viable fat cells, in the channels of the syringe 10.

[0079] In this embodiment, a detent 52 formed on the plunger 26 engages the seal 38, causing a noticeable change in plunger travel to alert the user that the plunger has been retracted a certain distance. In this case, the detent 52 is formed to provide a warning when the plunger 26 has been retracted a sufficient distance to expose approximately two-thirds of the absorbent chamber to the bodily fluid. Since the majority of the bodily fluid absorption occurs at this point, the user need only agitate the bodily fluid and / or subsequently draw a saline rinse into the syringe, as described in more detail below. Such a two-part absorption process results in a higher overall quality fat graft. Of course, in other embodiments utilizing an absorption process having three or more absorption steps, one or more stoppers may be utilized.

[0080] The method of immobilizing fat cells for microfat grafting involves returning plunger 26 to at least the second position so that the second portion of the bodily fluid is not exposed to absorbent material 34. In this position, the second portion of the bodily fluid containing the live fat cells is located within first portion 16 of barrel 14 and can be returned to the implantation location in the body.

[0081] As previously discussed, different embodiments of the syringe 10 have different absorbent materials and filters 20 that aid in separating the liquid portion of the bodily fluid from the live fat cells. In such embodiments, the exposing step further wicks up a first portion of the bodily fluid by capillary action and / or filters the bodily fluid. Additionally, with the plunger 26 retracted from the first position to expose the bodily fluid to the absorbent material 34, agitation may be provided within the syringe 10 to promote absorption. Agitation within the syringe 10 may be achieved by mechanical or physical means such as rolling and / or shaking the syringe and / or rotating the syringe along its longitudinal axis. More specifically, an external device may be utilized to roll and / or shake the syringe 10 and the bodily fluid therein, or it may be mounted on a rotating external device that utilizes centrifugal force to force the fluid portion of the bodily fluid into the absorbent material 34.

[0082] After separating the live fat cells from the first or fluid portion of the bodily fluid and placing the cells in the barrel 14 of the syringe 10 as described above, the live fat cells or fat graft are ready for reintroduction into the body. The same syringe 10 may be used to reinject the live fat cells, or, if the user prefers, the fat graft may be transferred and expelled in one or more portions into one or more smaller syringes. The transfer to the smaller syringes may be accomplished in a closed system utilizing the Luer-Lock connection fittings of the syringes. For example, tubing may be connected to the fitting at one end and connected to the first, smaller syringe at a second end, or the connection may be accomplished in another manner.

[0083] In using the above syringe embodiments, a user makes a puncture incision at the desired collection site in the human body. A collection device, such as a cannula, is connected to the syringe via a Luer-Lock or other connection fitting located on the proximal portion of the syringe barrel. The cannula is then inserted into the body. The user retracts the plunger of the syringe and moves it in a manner well known to those skilled in the art. A vacuum is created in the syringe barrel, which results in the drawing of bodily fluid into the barrel. This vacuum can be created using the plunger and / or a secondary vacuum source. The user continues to retract the plunger to maintain a constant low vacuum as the procedure continues. Graduations printed on the syringe barrel, or indentations or a raised ring can be used to indicate the amount of bodily fluid that has been collected. In one embodiment, the user does not need to hold the plunger in the desired position, as a release plunger retention mechanism can lock the plunger in place regardless of the retracted position. This process continues until the desired amount of fluid is obtained, or until at least the proximal portion of the barrel is full.

[0084] The cannula is then removed from the body and the proximal tip of the syringe is oriented upward. The plunger is then retracted by the operator sufficiently until it contacts the stopper formed by the top cap in this embodiment, thus exposing all of the bodily fluids through the filter to the absorbent material. After the plunger is retracted, the syringe can be held in a vertical position or gently agitated by rolling, rotating, and / or shaking. After a period of fluid absorption with the syringe oriented upward, the user returns the plunger, expelling any remaining live fat cells to the proximal portion of the barrel and expelling any remaining air. The same cannula used for collection, or a different cannula, hypodermic needle, or reinjection device is then reattached to the attachment. The reinjection device is inserted into the body at the implantation site. The plunger is then advanced to expel the treated fat graft through the cannula and into the implantation site. In another embodiment, the treated graft may be expelled in an open or closed transfer process into another container or syringe(s). The above syringes are of the type that are discarded after one use.

[0085] In another method of the present invention, the body fluid may be drawn into the first channel of the first portion 16 of the syringe barrel 14 by the suction action created by the withdrawal of the plunger 26. A volume of irrigation solution (such as saline or lactated Ringer's solution) approximately 25% of the body fluid volume is similarly drawn into the first channel and added to and mixed with the body fluid. The body fluid / irrigation mixture is then drawn into the second channel defined by the filter 20 until it reaches a distinctive landmark, which in the illustrated embodiment is a stopper 52 engaging the seal 38. The mixture is allowed to dwell in this position for a predetermined period of time, preferably about one minute, during which a portion of the mixture passes through the filter and is absorbed by the absorbent material 34. During this time, the syringe 10 may be mechanically agitated or rotated to cause additional mixing and maximize exposure to the absorbent material 34.

[0086] The remaining, non-absorbed portion of the fluid / wash mixture remaining in the second channel is then returned to the first channel, and plunger 26 is used to add a second specific amount of wash solution (e.g., again about 25% of the initial fluid). The mixture of treated fluid and additional wash solution is drawn into the second channel, except now syringe 26 is retracted past the mark, so that the entire filter 20 and absorbent 34 can be exposed to the next mixture. Similarly, the mixture is allowed to dwell in this area for a predetermined period of time, preferably about one minute, so that the next mixture portion passes through the filter and is absorbed by absorbent 34. Similarly, syringe 10 can be mechanically agitated or rotated during this second period of time, so that additional mixing occurs and exposure of absorbent 34 is maximized. Using this multi-step method results in a high percentage of the undesirable free oil(s) and aqueous components of the fluid mixture being absorbed. Following the second residence time, the remaining or non-absorbed portion of the mixture, consisting primarily of highly concentrated adipocytes, then passes from the second channel back into the first channel, ready for reinsertion into the implantation site, as previously described.

[0087] In summary, there are numerous advantages to a syringe for withdrawing fluid from the body for microfat grafting and a corresponding method for using the syringe to capture fat cells for microfat grafting. All of the above descriptions have been presented for purposes of illustration and description. There is no intent to limit the embodiments to the precise form disclosed. Obvious variations and modifications are possible in light of the above teachings. Plunger locking mechanisms may be used in any of the above described embodiments, including, for example, a releasable retention system that locks the plunger in a partially retracted position upon retraction, a friction locking mechanism, a flexible rubber flange that locks with a wedge against the plunger cylinder, an offset collar that locks with a wedge against the plunger cylinder, and a ratchet system that indexes at a specific point against the plunger cylinder. Each of these locking mechanisms is generally known in the art and serves to maintain a vacuum at least in the proximal portion of the syringe barrel. All of these variations and modifications are within the scope of the following claims, when interpreted in accordance with what is fair, legal, and equitable. [Explanation of symbols]

[0088] 10 Syringe 12 Fluid coupling 14 barrels, syringe barrels 16 Part 1 18 Part 2 20, 46, 72 filters 24 Inner wall 26 Plunger 28 Gasket, plunger gasket 30 Filter Assembly 32 Absorption chamber, chamber 34 Absorbent material 36 Cap 38 Seals, sealing gaskets 38 Gasket or O-ring 44 Cartridge 48 First support or proximal support 50 notches 52 Second support part 52 Detent 54 Support surface 56 Circular Ring 58 Ledge (protrusion) 74 Laser welding 76 Proximal end 78 Distal end 76 and 78 Flared Ends

Claims

1. A syringe used to collect aspirated material containing fat cells from the body for fat grafting, A barrel having a first part and a second part, wherein the inner wall diameter of the first part is smaller than the inner wall diameter of the second part. The adipose cells are separated from the aspirated material, and a filter extending within the second portion of the barrel, An absorbent material located between the filter and the inner wall of the second portion, which absorbs residual aspirated material that passes through the filter, and A plunger that moves longitudinally within the barrel along the inner wall of the first portion and the filter, the plunger having a gasket attached to the proximal end of the plunger that forms a seal together with the inner wall of the first portion at a first position and the inner wall of the filter at a second position, A syringe characterized by having the following features.

2. The syringe according to claim 1, wherein the inner wall of the second portion of the barrel forms a notch for receiving the proximal end of the filter.

3. The syringe according to claim 2, wherein an outward-facing flare is formed at the proximal end of the filter.

4. The syringe according to claim 2, further comprising a proximal support portion configured to receive the proximal end of the filter.

5. The syringe according to claim 4, wherein the proximal support portion seals and engages with at least the notch.

6. The syringe according to any one of claims 1 to 5, further comprising a distal support portion configured to receive the distal end of the filter and to form a central opening into which the plunger extends.

7. The syringe according to claim 6, wherein the distal support portion has a disk that forms the central opening and has radial outer edges.

8. The syringe according to claim 7, wherein the distal support portion further has an annular ring extending distally from the disk.

9. The syringe according to claim 8, wherein the inner diameter of the annular ring is larger than the diameter of the central opening that forms a ledge facing distal to the disk.

10. The syringe according to any one of claims 1 to 5, wherein the outer wall of the filter and the inner wall of the second portion of the barrel at least partially form a chamber in which an absorbent material is present.

11. The syringe according to claim 10, further comprising a cap that engages with the distal end of the barrel and forms the chamber in which the absorbent material is present.

12. The syringe according to any one of claims 1 to 5, wherein the filter is a mesh filter.

13. The syringe according to claim 1, further comprising a second filter that extends within the chamber and is located between the outer wall of the filter and the absorbent material.

14. The syringe according to claim 13, wherein the second filter and the absorbent material form a cartridge.

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