Technical field of the invention

The present invention generally relates to aesthetic medicine and surgery and in particular to a device for the filtration of fat extracted by way of surgical liposuction procedures.

Background

Liposuction has been introduced since the 70s of the last century. Initially it was a very invasive interv ention carried out under general anesthesia in major surgery rooms. The procedure took several hours and fat in excess was sucked by way of large cannulas with a diameter ranging from 1 to 4 cm connected to a high-power suction unit. The fat was then eliminated along with large amounts of blood and anesthetic. In many cases, blood transfusions were required in the days following an intervention and many complications and deaths are reported in medical literature.

Less invasive liposuction techniques have been developed only since the 90s of the last century. The size of the cannulas has been progressively reduced up to diameters of 2-5 mm. The introduction of the tumescent anesthesia technique has allowed to carry out surgical interventions under local anesthesia. According to the tumescent technique a large volume of liquid containing a local anesthetic combined with a vasoconstrictor (adrenaline) is injected in an area to be treated. This injection reduces the pain caused to the patient during suction of fat and allows to limit bleeding, thus making liposuction easier and less dangerous.

The so-called "lipofilling" procedures have been developed over the past 20 years. These procedures exploit the sucked fat as a filler to reshape and increase of the volume of breast, gluteus and calf. Face wrinkles may also be filled and corrected, lips, cheekbones and chin may be reshaped as well .

Therefore it has become necessary to preserve the integrity of the sucked fat as much as possible. Unlike the first liposuction procedures, in fact, fat is no longer eliminated, but becomes a resource in the frame of the aesthetic procedure. The effectiveness of this resource is closely related to the survival of fat cells, i.e. adipocytes and stem cells and adipocyte precursor cells. These cells are taken from a site where they are in excess (thighs, abdomen, hips) and are grafted on a site to be reshaped (breasts, lips, etc.). The procedure is very delicate and is always accompanied by the death of a variable percentage of adipocytes. The survival rate ranges between 70%, in the better cases, and below 10%, which means failure of the lipofilling procedure.

The survival of fat cells is linked to several factors, such as their individual properties, the degree of oxidation of the tissues, the type of infiltration technique, the fact that the patient is a smoker, the trauma caused by a cannula during the sucking process, etc. The local anesthetic used to numb the surgical site is among the most important damaging factors for the adipocytes, because it has a toxic effect on the cells in the 1 2-24 hours subsequent to their graft into the target site. Damage is increased by the presence of erythrocytes that have an important oxidative effect if left with fat cells. In order to reduce tissue damage cannulas of a smaller size have recently been developed. These cannulas can be more easily inserted in the fatty tissue thus reducing the force to be applied. Cannulas having special patterns and shape of the holes through which fat is sucked have also been developed. An example of such cannulas is described in the Italian patent application no. 10201 5902323792 in the applicant ^' s name.

During a liposuction procedure it is necessary to inject an anesthetic solution into the site from which fat has to be sucked. The anesthetic is usually injected by way of syringes.

Once made the anesthesia, suitable liposuction cannulas are mounted on the same syringes employed for this purpose and used to suck fat. The sucked fat is mixed with local anesthetic and blood. The difference in specific gravity is usually exploited as a means to separate adipocyte cells from the liquid mixture. To this aim the syringes are kept vertically manually or by way of suitable racks. Fat has a lower specific gravity and is collected in the upper part of a syringe, i .e. towards the plunger, while the liquid mixture is deposited in the lower part of the syringe, wherein an attachment member of the cannula is arranged, and can thus be eliminated.

In order to ensure survival of adipocyte cells in view of a subsequent lipofilling procedure, the fat remaining in the syringe must be processed with a washing solution, typically a physiological solution, for one or more cycles so as to purify it from residual blood and anesthetic. Blood and anesthetic are in fact toxic to adipocytes. More particularly, in each cycle a certain amount of washing solution is sucked into the syringe, which is then positioned vertically so as to allow separation of fat and liquid, the latter consisting of physiological solution, residual blood and anesthetic. The liquid deposited in the lower part of the syringe because of its higher specific gravity is then eliminated and fresh physiological solution is sucked into the syringe so as to carry out another washing and separation cycle.

A number of different containers are generally employed for the above operations, whose success is highly dependent on the manual ability of an operator. The containers must be properly prepared and organized before surgery. For example, a first container is filled with physiological or saline solution, a second container is filled with an anesthetic and a third container is used to collect the liquid to be eliminated at each cycle of the purification process. These containers are generally open and thus exposed to a possible contamination by bacteria present in an operating room.

Summary of the invention

The technical problem posed and solved by the present invention is to improve purification procedures of the fat extracted by liposuction, with particular reference to devices employed in the purification procedures.

The invention consists in a filtration device comprising a filter element on one side of which a connection member is arranged allowing to connect a syringe containing fat extracted from a patient during a liposuction procedure. The syringe also contains a liquid mixture consisting of blood and anesthetic that are sucked with the fat. On the opposite side of the filter element a first reservoir containing a physiological solution and a second, empty reservoir are connected in parallel by way of a three-way connector. The filter element is configured to hold fat cells and let the liquid mixture pass.

The filtration device is configured such that by injecting the content of the syringe towards the filter element, the liquid mixture crossing it is directed to and collected in the second, empty reservoir, whereas by operating the plunger of the syringe in the opposite direction, washing solution is sucked from the first reservoir through the filter element. The washing solution is then mixed with the fat and the residues contained in the syringe. An assembly of one-way valves, taps and/or filters ensures tightness of the device, resulting in a reduction of the contamination and subsequent infection risks.

Therefore, by cyclically repeating the injection and suction steps, the fat contained in the syringe is progressively purified from residues of blood and anesthetic.

The main advantage offered by the invention is therefore to provide a surgeon with a filtration dev ice for fat (formed by adipocytes, adipocyte precursors and stem cells) that, thanks to the provision of a filter element, allows to carry out in a reliable and repeatable way all the operations that are typically performed manually by using individual containers. Subsequent lipofilling procedures employing the fat so purified have greater chances of success than procedures employing fat purified by known methods.

Another important advantage offered by the invention is that the fat purification procedure is simpler and faster than procedures carried out according to the prior art.

According to an embodiment of the invention, the filtration device is configured so as to allow connection of a plurality of syringes in parallel, thus advantageously allowing to treat larger quantities of fat. To this aim, a duct provided with a plurality of attacks that are selectively accessible for the mounting of a plurality of respective syringes is connected to the filter element.

A further filter element may be connected to the duct, as well as a three-way connector for the connection of a further reserv oir containing physiological solution and a further, empty reservoir for collecting the liquid mixture separated from the fat, both reservoirs being arranged on the opposite side of the further filter element. This configuration provides the additional advantage of improving the filtration device, which can thus purify an even larger amount of fat.

The liquid mixture collected in the second reservoir typically has disposal problems, because it has an organic content that is mainly liquid and undergoes a rapid degradation resulting in unpleasant odors. According to an embodiment of the invention, an element made of or comprising an absorbent material can be advantageously arranged in the second reservoir so as to allow easier disposal of the liquid mixture.

Further advantages and features of the filtration device according to the present invention will become clear to those skilled in the art from the following detailed and non-limiting description of embodiments thereof, with reference to the accompanying drawings.

Brief description of the drawings

Reference will be made to the figures of the accompanying drawings, in which:

- Figure 1 schematically shows a filtration device according to an embodiment of the invention;

- Figure 2 schematically shows a filtration device according to an alternative embodiment of the invention;

- Figure 3 schematically shows a filtration device according to a further embodiment of the invention.

Detailed description of preferred embodiments of the invention

With reference to figure 1 , a filtration device according to the invention is generally indicated by reference numeral 100 and comprises a first reservoir 1 10, in the form of a receptacle, container or bag, filled with a washing solution adapted to be sucked by a syringe 200 containing a certain amount of fat mixed with blood and anesthetic. The filtration device 100 further comprises a second, empty reservoir 120 intended to cyclically receive from the syringe 200 a liquid mixture consisting of the sucked washing solution and of the blood and anesthetic separated from the fat.

The device 100 also comprises a least one filter element 1 30 connected on one side to the first reservoir 1 1 0 and to the second reserv oir 1 20 through a three-way connector 140. A one-way valve 141 is arranged on the branch of the connector 140 connected to the first reservoir 1 10. The one-way valve 141 is configured to allow passage of a fluid flow, in this case washing solution, from the first reservoir 1 10 to the connector 140. On the branch of the connector 140 connected to the second reservoir 120 a one-way valve 142 is arranged. The one-way valve 142 is configured to allow passage of a fluid flow, in this case the washing solution together with blood and anesthetic, from the connector 140 toward the second reservoir 120. Flow directions are schematically shown in figure 1 by arrows.

A connection member 1 3 1 is arranged on the side of the filter element 130 opposite to. the side to which the first and second reservoirs 1 10, 120 are connected. The connection member 1 3 1 , such as e.g. a standard ^* 'luer-lock" attack, is configured to allow connection of the syringe 200.

The filter element 1 30 is configured to hold fat cells and/or stem cells and adipose tissue precursors and let the liquid mixture pass. To this aim the filter element 1 30 includes meshes with apertures having a size ranging between 10 and 200 microns, preferably between 1 5 and 100 microns. The filter element 130 can be made up of a number of filters having a different mesh size in order to optimize the filtration process.

For the same purpose a plurality of filter elements 1 30 may also be arranged in series.

In the figures, the junctions zones between the various components of the device are schematically indicated by hatching with parallel lines, and may advantageously comprise shut-off and flow control valves, for example taps. For instance, two taps

1 30a, 1 30b are arranged at the opposite ends of the filter 1 30 and respectively attached to the connection member 1 3 1 and to the connector 140.

In order to cany out a purification procedure of fat sucked into the syringe 200 in view of a lipofilling procedure, the syringe is mounted on the connection member 1 3 1 and its entire content is injected into the filter element 1 30 by acting on the plunger. Fat cells are held by the filter element 130, which instead lets the liquid mixture consisting of washing solution, blood and anesthetic pass. More particularly, blood consists of a liquid component, the plasma, and of a corpuscular component having small size elements. The average diameter of red and white blood cells is in fact comprised between 5 and 12 microns. The liquid component and the blood enter the three-way connector 140 and are collected in the second reservoir 1 20 after crossing the one-way valve 142. As explained above, it will be understood that in this phase the one-way valve 141 prevents entry of the liquid mixture and of the blood into the first reservoir

1 10.

By operating the plunger of the syringe 200 in the opposite direction, namely by pulling it from the syringe body, the one-way valve 142 of the connector 140 is closed, whereas the one-way valve 141 is opened thus allowing suction of washing solution from the first reservoir 1 10 through the filter element 130. Fat is thus mixed inside the syringe 200 with the washing solution coming from the first reservoir 1 1 0.

The syringe 200 so filled with fat and washing solution is again discharged as explained above thus carrying out a new purification cycle of the fat, which is held by the filter element 1 30 purified from the liquid mixture, this time consisting of washing solution and residues of blood and anesthetic.

Further purification cycles are then carried until the fat sucked into the syringe is completely free from residues of blood and anesthetic, and is therefore in the ideal condition to be used in a subsequent lipofilling procedure.

In order to ensure the best outcome of a purification procedure, the device 100 according to the invention may advantageously comprise a microfilter 1 50 arranged between the first reservoir 1 10 and the one-way valve 141 connecting it to the connector 140. The microfilter 1 50, e.g. provided with meshes with a passage size in the order of fractions of a micron (0.2 micron for example), allows to retain any impurities and bacteria present in the washing solution sucked into the syringe 200, which would otherwise be mixed with the fat.

Still in the aim to ensure the best outcome of a purification procedure, the device 100 may also advantageously comprise a safety valve calibrated to be opened beyond a predetermined pressure threshold.

The safety valve, schematically indicated with the reference number 1 60, is connected in a branch configuration to the connection member 1 3 1 of the filter element 1 30.

The use of a safety valve allows to limit the maximum injection pressure of the fat towards the filter element 1 30, and therefore to limit the mechanical compression of fat cells against its meshes, thus ensuring higher chances of survival during a purification procedure. The possible portion of fat and liquid mixture discharged through the safety valve 160 may be collected into a container (not shown) connected thereto, or, more advantageously, into a further syringe (not shown). In this way, the fat collected into the additional syringe may be reintroduced into the device and will not be lost.

The safety valve 160 may be advantageously associated with a pressure sensor (not shown) provided with a visual and/or sound indicator, which allows a user to reduce the pressure exerted on the plunger of the syringe 200 in case the predetermined pressure threshold is exceeded. After washing, residues of fat possibly present in the filter can be collected in a container (not shown) connected thereto or, more advantageously, in a further syringe (not shown). In this way, the fat present in the filter and in the device will not be lost.

Still in order to ensure the best outcome of the purification procedure and to minimize loss of fat in the device 1 00, this may also advantageously comprise two taps arranged immediately above and immediately below the filter 1 30, as well as a third tap equipped with a luer-lock or similar attack.

According to a further aspect of the invention, the second reserv oir 1 20 may comprise an element 1 21 made of or comprising an absorbent material. In this way, washing liquid and blood can be eliminated in a simpler and faster way. According to an embodiment of the invention, the element made of an absorbent material is contained in a film of a water-soluble material, in turn enclosed in a disposable envelope, as described in the patent publication EP 2452660 A l .

A sensor 1 32 adapted to measure the relative percentages of fat and washing solution may be advantageously connected to the connection member 1 3 1 . The sensor may e.g. include an electrical impedance, an infrared measuring device of the type NIR (Near-Infrared Interactance), an electromagnetic field generator of the type TOBEC (Total Body Electrical Conductivity), or an x-ray system of the type DEXA (Dual Energy X-Ray Absorptiometry).

The device 100 according to the invention may advantageously be placed on a scale 1 70, schematically shown in dashed lines, e.g. arranged under the first and the second reservoirs 1 10, 1 20 for measuring the weight of the amount of fat and liquid mixture sucked from a patient and intended to be purified.

According to a further aspect of the invention, the second reservoir 1 20 may include an outlet 122 configured for the discharge of the liquid mixture. The outlet 1 22 is preferably disposed proximate to the bottom of the second reservoir 120 so as to facilitate its emptying. A filter element 123 configured for the filtration of specific cellular elements which pass through the filter element 1 30 together with the liquid mixture may be advantageously associated with the outlet 122, The filter element 1 23 may for example have passages with a size in the order of 12- 1 80 microns.

Now referring to figure 2, an alternative embodiment of the device 100 according to the present invention is disclosed, the device being configured so as to allow connection in parallel of a plurality of syringes.

Similarly to the first embodiment of the invention, also in this case the device 100 comprises a first reservoir 1 10, i.e. a receptacle, a container or a bag (hereinafter named reservoir) filled with a washing solution and a second, empty reservoir 120, i.e. a receptacle, a container or a bag (hereinafter named reservoir), intended to cyclically receive from the syringe 200 a liquid mixture consisting of the sucked washing solution, blood and anesthetic separated from the fat.

The device 1 00 also comprises a filter element 1 30 connected on one side thereof to the first reservoir 1 10 and to second reservoir 120 through a three-way connector 140. A one-way valve 141 configured to allow passage of washing solution from the first reservoir 1 10 to the connector 140 is arranged on the branch of the connector 140 connected to the first reserv oir 1 10. On the branch of the connector 1 40 connected to the second reservoir 120 a one-way valve 142 configured to allow passage of the washing solution, blood and anesthetic, from the connector 140 toward the second reservoir 1 20 is arranged. The flow directions are schematically shown in figure 2 by means of arrows.

A connection member 1 3 1 configured for the connection of the syringe 200 is arranged on the opposite side of the filter element 1 30. The connection member 1 3 1 may be e.g. a standard "luer-lock" attack.

In order to allow mounting in parallel of a plurality of syringes 200, the device 100 also includes a duct 1 80 connected in a branch configuration to the connection member 1 3 1 of the filter element 130. The duct 1 80 is arranged in fluid communication with the connection member 1 3 1 and comprises a plurality of mounts 1 81 , for example of the "luer-lock" type, that are selectively accessible so as to connect respective syringes in parallel, e.g. a second syringe 201 and a third syringe 202. Each syringe can inject its content into the filter element 1 30, suck physiological solution from the first reservoir 1 10 and discharge the liquid mixture separated from the fat into the second reservoir 1 20. In other words, the overall configuration of the device 100 is such that all the syringes can perform in parallel the purification procedure of the fat they contain by using the first and the second reservoirs 1 10, 1 20 as described above. Taps 1 82, for example three-way taps of the type "Stopcoks", may advantageously be arranged in the duct 1 80 in correspondence with each syringe mount. The taps 1 82 allow to selectively adjust the flow of fat and liquid mixture within the device 100.

According to a further embodiment of the invention, shown in figure 3, the device 100 is configured for the connection of a plurality of syringes as described above, and may advantageously comprise a further filter element 1 30' provided with a respective connection member 1 3 Γ connected to the duct 1 80 and configured for the connection of a further syringe 203 , as well as a possible further first reservoir 1 10' filled with a physiological solution and a possible further second, empty reservoir 1 20' intended to receive the liquid mixture separated from the fat. The second reservoir 120' may possibly be provided with an element 1 2 1 ^" made of or comprising an absorbing material.

Similarly to the embodiments described above, the attack 1 3 1 ' may be associated with a safety valve 160' , as well as with a sensor 1 32' adapted to measure the relative percentages of fat and washing solution.

Moreover, the further first and second reservoirs 1 10', 1 20' are connected to the further filter element 1 30' through a three-way connector 140' and one-way valves 141 ^" , 142' that are respectively configured to allow passage of physiological solution from the first reservoir 1 10' to the connector 140 ^* and from the connector 140' to the second reservoir 120' .

This configuration of the filtration device 100 allows to increase the amount of fat contained in the swinges arranged in parallel that can be subjected to the purification procedure.

The invention has herein been disclosed with reference to preferred embodiments thereof. It is to be understood that there may be other embodiments based on the same inventive concept, as defined by the scope of protection of the claims set out below.