Patent Document

FIELD 
       [0001]    A tissue transfer cannula and method for producing a tissue transfer cannula are disclosed. More particularly, a tissue transfer cannula with a substantially continuous interior pathway and method for producing such a cannula are disclosed. 
       BACKGROUND 
       [0002]    Microlipoinjection is a process in which fat is taken by a cannula from one spot in the body and reinjected in another place in the body. Microlipoinjection has also been known as liposuction with fat transfer, fat grafting or fat transplantation. In general, microlipoinjection is performed to treat divots and scar indentations from trauma to the face or body, such as may occur as a secondary effect of domestic trauma, surgery or infection. Microlipoinjection can also be used to treat the effects of the loss of the subcutaneous layer of fat due to the normal aging process, either alone or in combination with facelift and fat grafting techniques. Microlipoinjection can also be used for providing filler to reapproximate weakened vocal cords, fill sinuses, or partially close incompetent valves. 
         [0003]    In addition, every mass of fat in the human body has with it a varying number of adult stem cells. These stem cells are the precursor to healthy fat cells. In addition to readily developing into normal fatty tissue, they have a limited ability to differentiate into different tissue. When placed in fat they will divide several times into mature fat cells and more adult stem cells. These stem cells are an important part of a tissue harvest. 
         [0004]    Up to about 1990, there were few artificial filler substances available to surgeons. Accordingly, surgeons used human bone, collagen and fat as fillers. However, the use of fat was not very successful, because the instruments and techniques were not sufficiently refined. For example, 50% of the fat may not have lived through the transplantation process. As a result, surgeons would need to implant more fat than would be required if all of the fat survived the process, or the transplantation process would have to be repeated multiple times or both. 
         [0005]    More recently, a number of filler substances, such as Restylane Hyaluronic Acid, Collagen, Fibril, ePTFE (Teflon®), Hylan B Gel, Artecol, BioBlastique and have been used. These substances have proved effective at filling small areas, but the cost for larger areas has become prohibitive. For this reason, as well as interest in the “natural substance” concept, surgeons and their patients have again looked at using fat as a filler. 
         [0006]    With the renewed interest in using fat as a filler, techniques have been refined to provide a better fat graft “take” with revascularization. However, the instruments and devices conventionally available to perform the procedure remain clumsy and ill-suited for the procedure. 
         [0007]    Commonly available liposuction handles and cannulas often have severe drop-offs, blind pockets, or other discontinuities in the tissue pathway. These discontinuities result in an instrument that is difficult or impossible to clean. In addition, two piece instruments featuring separable handle and cannulas can make cleaning the instrument even more difficult where at least some portion of the tissue pathway is formed by the handle. In particular, discontinuities in the interior pathway of the cannula and/or handle creates drop-offs or blind pockets that are difficult or impossible to clean. For example, tissue can become impacted in such areas, posing a risk of contamination. Typical systems that feature separable cannulas and handles can also be expensive to manufacture, because of the fittings required to effect a secure connection between the cannula and handle. 
         [0008]    In addition to drop-offs, blind pockets and other discontinuities along the length of a tissue transfer channel, typical cannulas often include blind pockets at their tip, which are difficult or impossible to clean. The shape of the outer surface of cannulas also can be such that the practitioner using the instrument must exercise special care to avoid damage to tissue that is not to be removed from the body. 
         [0009]    Accordingly, it would be desirable to provide a cannula and/or a cannula and handle system that was easy to clean. In addition, it would be desirable to provide a system in which a cannula could be secured to a handle in a secure fashion, and that was economical to produce. It would also be desirable to provide a cannula that removed tissue to be transferred efficiently, and with reduced damage to that tissue and to neighboring tissue. 
       SUMMARY 
       [0010]    Embodiments of the disclosed invention are directed to solving these and other problems and disadvantages of the prior art. In accordance with embodiments of the disclosed invention, a cannula with an interior pathway or channel that is without discontinuities that can be difficult or impossible to clean is provided. In addition, the inlet to the cannula is formed such that no blind pocket is created at a distal end of the cannula. In accordance with still other embodiments of the disclosed invention, at least a portion of the outer surface of the cannula is non-circular, to facilitate securing the cannula to a cannula handle. 
         [0011]    A cannula in accordance with embodiments of the disclosed invention includes an inlet comprising one or more holes. The hole or holes at the most distal end of the interior pathway coincide with and/or define the distal end of the interior pathway. Accordingly, no blind pocket or pockets are formed. In addition, the hole or holes of the inlet can be sized so that they each have an area that is less than the cross-sectional area of the interior pathway of the cannula. Smaller holes produce smaller fat parcels, which pass through the cannula faster secondary to less friction on the walls. In accordance with still other embodiments of the disclosed invention, the inlet includes a plurality of holes that extend along or span no more than two inches of the distal end of the cannula. From the inlet at the distal end of the cannula to the outlet at the proximal end of the cannula, the interior pathway is substantially continuous, without any drop-offs, blind pockets or other discontinuities. 
         [0012]    A cannula and handle system in accordance with embodiments of the disclosed invention can include a handle with a receiving channel. When the cannula and handle system is assembled for use, the distal end of the cannula extends from a first or distal end of the handle, while the proximal end of the cannula extends from the second or proximal end of the handle. Moreover, no portion of the handle defines the interior pathway along which tissue is transported. Instead, the interior pathway, from the inlet to the outlet, is defined entirely by the cannula. Accordingly, the cannula includes the only portion of the cannula and handle system through which tissue that is harvested for reinjection is passed. 
         [0013]    The distal portion of the cannula can include an outer surface that is non-circular in cross-section. This can provide a secure connection between the cannula and handle of a cannula and handle system. A corresponding portion of a receiving channel of the handle can mate with at least a portion of the non-circular surface of the cannula, preventing rotation of the cannula relative to the housing. In addition, a transition between the non-circular portion and another portion of the cannula can, together with a corresponding portion of the handle receiving channel, form a stop that prevents movement of the cannula relative to the handle in a first direction along a longitudinal axis of the cannula, as well as preventing rotation of the cannula relative to the handle. In accordance with further embodiments of the disclosed invention, the non-circular outer surface of the cannula may extend from the tip of the cannula to a section of the cannula that is received by the handle when the handle and cannula are joined to one another. By providing an oval or flattened distal end, dermal damage resulting in subcutaneous scarring can be reduced as compared to a round cannula. In accordance with still other embodiments, the cannula can be in two pieces, with a first piece that extends through and is integral with the handle, and a second piece that includes the inlet and that is interconnected to the first piece. 
         [0014]    A method in accordance with embodiments of the disclosed invention for producing a cannula includes plugging a tubular member at one end, to form the tip of the cannula. An inlet is formed at the proximal end of the cannula. The inlet hole intersects and passes through at least a portion of the plug, thereby forming a distal end of the interior pathway. Moreover, the distal end of the interior pathway is formed such that no blind pocket is formed at the distal end of the cannula. In accordance with further embodiments, the non-circular portion of the cannula can be formed by applying pressure to flatten the cannula body, such that the deformed portion has an oblong or other non-circular cross-section. 
         [0015]    Additional features and advantages of embodiments of the present invention will become more readily apparent from the following discussion, particularly when taken together with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  illustrates a cannula and handle system in elevation in accordance with an embodiment of the disclosed invention; 
           [0017]      FIG. 2  is a cross section of the cannula and handle system of the embodiment of  FIG. 1  in elevation; 
           [0018]      FIG. 3  is a cross section of the cannula and handle system of the embodiment of  FIG. 1  in plan view; 
           [0019]      FIG. 4  is a cross-section of a cannula in accordance with an embodiment of the disclosed invention in elevation; 
           [0020]      FIG. 5  is a cross-section of the cannula of  FIG. 3  in plan view; 
           [0021]      FIG. 6A  is a transverse cross-section of the cannula illustrated in  FIG. 4 , taken along section line A-A; 
           [0022]      FIG. 6B  is a transverse cross-section of the cannula illustrated in  FIG. 4 , taken along section line B-B; 
           [0023]      FIG. 7A  is a transverse cross-section of a handle as illustrated in  FIG. 2 , taken along section line C-C; 
           [0024]      FIG. 7B  is a transverse cross-section of a handle as illustrated in  FIG. 2 , taken along section line D-D; 
           [0025]      FIG. 7C  is a transverse cross-section of a handle as illustrated in  FIG. 2 , taken along section line E-E; 
           [0026]      FIG. 8  is a cross-section of a cannula in accordance with other embodiments of the present invention in elevation; 
           [0027]      FIG. 9  is a cross-section of the cannula of  FIG. 8  in plan view; 
           [0028]      FIG. 10  is a cross-section of a cannula in accordance with other embodiments of the present invention in elevation; 
           [0029]      FIG. 11  depicts the cannula of  FIG. 10  in plan view; 
           [0030]      FIG. 12  is a transverse cross-section of the cannula illustrated in  FIG. 10 , taken along section line F-F; 
           [0031]      FIG. 13  is a cross-section of a cannula in accordance with other embodiments of the present invention in elevation; 
           [0032]      FIG. 14  is a cross-section of a cannula and handle system in accordance with other embodiments of the present invention; and 
           [0033]      FIG. 15  is a flow chart illustrating aspects of a process for producing a cannula in accordance with embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    A cannula and handle system  100  in accordance with embodiments of the disclosed invention is illustrated in elevation in  FIG. 1 . The cannula and handle system  100  includes a cannula  104  and a handle  108 . The cannula  104  includes a distal or anterior portion  112  that includes a tip  114  and an inlet  116  made up of a plurality of holes  120 . The cannula  104  further includes a proximal or posterior portion  124  that includes an outlet  128 . The cannula  104  generally extends through the handle  108 , such that tissue drawn into the inlet  116  is passed to the outlet  128 , without contacting any component other than the cannula  104  between the inlet  116  and the outlet  128 . The handle  108  may further include a hose or conduit coupler  132  that acts to secure a vacuum hose or conduit to the cannula and handle system  100 . 
         [0035]    As can be appreciated by one of skill in the art, when the cannula and handle system  100  is in use, a physician or other practitioner inserts the inlet  116  of the cannula  104  into an area of a body from which tissue is to be extracted. Extraction of tissue is generally performed in association with the application of a vacuum at the holes  120  of the inlet  116 , by connecting the outlet  128  of the cannula  104  to a vacuum source. For example, a first end of a length of tubing that is connected to the vacuum source at a second end of the tubing can be connected to the conduit coupler  132  such that the outlet  128  is positioned within the tubing. As can also be appreciated by one of skill in the art, tissue collected at the inlet  116  of the cannula  104  and passed through the outlet  128  of the cannula  104  may be deposited into a collection vessel for processing (e.g., washing or treatment) and reinjection into the body at a selected location. 
         [0036]      FIG. 2  illustrates the system  100  of  FIG. 1  in cross section. As shown in  FIG. 2 , the cannula  104  includes an interior pathway or tissue transport channel  204  that extends from the tip  114  of the distal portion  112  of the cannula  104  to the outlet  128  of the cannula  104 . In addition, it can be seen that tissue drawn in through the inlet  116  and passed to the outlet  128  does not come into contact with any other component of the system  100  other than the interior pathway  204  of the cannula  104 . In addition, it can be seen that the interior pathway  204  contains no drop-offs, blind pockets, or other discontinuities that might trap collected tissue and make cleaning difficult or impossible. Instead, the interior pathway  204  is smoothly contoured. Accordingly, the risk of infection can be reduced when extracted tissue is to be reinjected.  FIG. 2  also illustrates a shoulder or ramped portion  208  of the cannula  104  corresponding to a change in the contour of the exterior of the cannula  104 . The change in the contour of the outer surface of the cannula  104  is generally mirrored by the receiving channel  212  of the handle  108 . In particular, the shoulder portion  208  of the cannula  104  corresponds to a transition from an oval cross-section between the distal edge of the shoulder  208  and the tip  114  (see  FIG. 6A ), and a round cross-section between a proximal edge of the shoulder  208  and the outlet  128  (see  FIG. 6B ). In order to attach the cannula  104  to the handle  108 , the proximal end  124  of the cannula  104  is inserted into the distal end  216  of the handle&#39;s receiving channel  212 . 
         [0037]    In general, the distal portion of the receiving channel  212  can feature an oval cross-section (see  FIG. 7A ) between a tapered or transition portion  220  (see  FIG. 7B ), corresponding to the shoulder  208  of the cannula  104  when the cannula  104  is fully inserted in the handle  108 , and the distal end  216  of the receiving channel  212 . The proximal end  224  of the receiving channel  212  has a round cross-section (see  FIG. 7C ) sized to fit closely to the round cross-section of the proximal end  124  of the cannula  104 . In order to pass the proximal end  124  of the cannula  104  through this oval portion of the receiving channel  212 , the oval portion of the receiving channel  212  can be sized with a tolerance that allows the round cross-section of the proximal end  124  of the cannula  104  to be accepted. More particularly, the round outer diameter of the proximal portion  124  of the cannula  104  can pass through the distal portion  216  of the receiving channel  212 . In accordance with embodiments of the disclosed invention, the proximal portion  124  of the cannula  104  might undergo some deformation while the cannula  104  is being inserted into the handle  108 , as the cannula  104  will generally fit tightly within the channel  212  of the handle  108 . In addition, the proximal portion  224  of the receiving channel  212  may be sized such that it features an inner diameter that is the same or close to the outer diameter of the proximal portion  124  of the cannula  104 . Moreover, the difference in width of the cannula  104  between the outside diameter of the round portion and the major axis  604  (see  FIG. 6A ) of the ellipse or oval cross-section of the distal portion  112  of the cannula  104  may, in combination with the tapered portion  220  of the receiving channel  212 , create a stop. For example, as illustrated in  FIG. 3 , when the receiving channel  212  is considered in plan view, the tapered portion  220  causes the width of the receiving channel  212  to decrease along the tapered portion  220  from the distal portion  216  to the proximal portion  224 . Moreover, this arrangement can provide a friction fit with a positive stop that prevents the cannula  104  from traveling in a more posterior direction relative to the handle  108 . As can be appreciated by one of skill in the art, when the system  100  is in use, the forces on the cannula  104  will tend to keep the cannula  104  seated securely in the handle  108 . Therefore, the cannula  104  can be secured to the handle  108  without requiring the inclusion of any additional mechanisms, such as a coupler, or potting material. In addition, the cannula can be removed from the handle  108  by pushing the proximal end  124  of the cannula  104  that extends from the proximal end of the handle  108  in a distal direction. In accordance with other embodiments, a coupler or locking mechanism can be integrated into the system  100  as an additional means by which the cannula  104  can be secured to the handle  108 . 
         [0038]      FIG. 4  is a cross-section of the cannula  104  of  FIG. 1-3  in elevation. As discussed above, the distal portion  112  of the cannula  104 , including at section line A-A, has an oblong or oval transverse cross-section as illustrated in  FIG. 6A . The proximal portion  124  of the cannula  104 , including at section line B-B, has a circular transverse cross-section as illustrated in  FIG. 6B . A cross-section of this same cannula in plan view is illustrated in  FIG. 5 . 
         [0039]    The cannula  104  illustrated in  FIGS. 1-5  features a oblong distal portion  124  and an inlet  116  that includes  24  holes  120 . These holes  120  can be distributed around the tip  114  of the cannula  104 . For example, the holes  120  can have a  3600  distribution as shown. In accordance with embodiments of the disclosed invention, the holes  120  of the inlet  116  may extend for a distance of from ½ to 2 inches from the tip  114  of the cannula  104 . In accordance with still other embodiments, the holes  120 , which can vary in number, extend for a distance of 1½ inches from the tip  114 . The holes  120  each have an area that is less than the area of the channel  204  through the cannula  104 . That is, the area A of the channel  204  (see  FIG. 6 ) is greater than the area of each individual hole  120 . In accordance with embodiments of the disclosed invention, the holes  120  are round. The holes  120  may be sized so that they are at least 0.0005″ smaller in diameter than the inner diameter of the interior pathway  204  of the cannula  104 . For cannulas  104  with an oblong transverse cross-section, the holes may be sized so that they are at least 0.0005″ smaller in diameter than the dimension of the inner pathway along the minor axis  608  of the interior pathway  204  (see  FIG. 6 ). In addition, the forward or distal most extent of the channel  204  at the tip  114  of the cannula  104  is defined by the leading edge of the pair of holes  120  closest to the tip  114  of the cannula  104 . Accordingly, the creation of blind pockets, which are difficult or impossible to clean, is avoided. 
         [0040]      FIGS. 8 and 9  illustrate a cannula  104  in accordance with other embodiments of the disclosed invention. The cannula  104  includes an inlet  116  having four holes  120 . The cannula  104  may otherwise be the same or similar to the cannula  104  illustrated in  FIGS. 1-5 , in that it includes a distal portion  112  that is oblong in cross-section and a proximal portion  124  that is round in cross-section. Accordingly, different cannulas  104  may be used in association with a common handle  108  design. Moreover, it should be appreciated that a cannula  104  in accordance with embodiments of the disclosed invention can have any number of holes. For embodiments in which a high rate of tissue collection is desired, a greater number of holes  120  is generally preferable. 
         [0041]    In accordance with further embodiments of the disclosed invention, the cannula  104  has no holes on the top surface to eliminate the possibility of sucking the dermis into the open holes  120  of the cannula  104 . A cannula  104  with no holes on a top surface is illustrated in  FIG. 10  in elevation, and in  FIG. 11  in plan view. In such an embodiment, all holes  120  of the inlet  116  are placed on the sides and the underside of the cannula  104 . For example, the top 90° of the cannula  104  is entirely without holes  120 , with all holes  120  being within the 270° that include the bottom and sides of the cannula  104  (see  FIG. 12 ). By providing a cannula without holes along substantially one surface, dissection close to the skin is facilitated by eliminating the possibility of sucking the dermis into the open holes  120  of the cannula  104 . 
         [0042]    The cannula illustrated in  FIGS. 10 and 11  also illustrates the inclusion of an air hole  1004 . When the cannula  104  is in use, the air hole  1004  admits air into the interior pathway  204 . The admission of air through the air hole  1004  can speed the harvest of fat by allowing a bubble of air to enter the interior pathway  204  and accompany the fat in transit. This is believe to speed the harvest by providing a cushion of air. The air is also believed effective in protecting the fat cells from damage. As illustrated, the air hole  1004  can be located anywhere along the length of the cannula  104 , between the inlet  116  and the outlet  128 . In accordance with embodiments of the disclosed invention, the air hole  1004  is located at some distance from the inlet  116 , at a location that would not normally be placed inside a body while fat is being harvested. An air hole  1004  as illustrated in  FIGS. 10 and 11  can be included in any cannula  104  in accordance with embodiments of the disclosed invention. As an example, the air hole  1004  may have a diameter of 1/64 of an inch. In accordance with still other embodiments, more than one air hole  1004  may be provided. 
         [0043]    The cannulas  104  illustrated in  FIGS. 1-12  feature an oblong (in cross section) distal section  112  that can reduce damage to the dermis. In particular, by featuring relatively flat surfaces there is less cannula apex near the dermis, and damage to the dermis adjacent the incision created in order to insert the cannula  104  into the body can be reduced. In other applications, especially those involving deeper dissection away from the dermis, and/or for particular practitioners, a round cross-section cannula may be desirable. Accordingly, as illustrated in  FIG. 13 , a cannula  104  in accordance with embodiments of the disclosed invention may have a round transverse cross-section. In addition, whether the distal portion  112  features an oblong, circular, or other transverse cross-section, the inlet  116  may incorporate different numbers of holes  120  in different designs or patterns. These different patterns may include providing a hole or holes  120  along one side of the cannula  104  only. 
         [0044]      FIG. 14  illustrates a two piece model or system  100 ′ in accordance with other embodiments of the disclosed invention. The system  100 ′ includes a cannula  104  that is provided in two sections, a proximal section  240 , and a distal section  244 . The proximal section  240  may be fixed to the handle  108 , for example by a threaded portion  248 . The proximal portion  240  may also incorporate a connector  252  that engages a mating connector  256  provided as part of the distal section  244  of the cannula  104 . In common with other embodiments is a channel  204  that extends from adjacent the tip  114  to the outlet  128 , and that is without drop-offs, blind pockets, or other discontinuities. Accordingly, the entire extent of the channel  204  is accessible, and therefore cleaning is facilitated. By providing a cannula  104  in two sections, cleaning can be further facilitated, for example by allowing the overall length of the cannula  104  to be reduced in order to place the instrument in an autoclave or other cleaning apparatus that is too small to receive the full length of the assembled cannula  104 . 
         [0045]    With reference now to  FIG. 15 , aspects of a process for producing a cannula in accordance with embodiments of the present invention are illustrated. Initially, a length of tubing is provided (step  1504 ). For example, the tubing may comprise an 18 inch length of stainless steel tubing having an inside diameter of 0.100 to 0.115 inches and an outside diameter of 0.120 to 0.130 inches. A determination may then be made as to whether the distal end  112  of the cannula is to have a non-circular cross-section (step  1508 ). If the distal end of the cannula is to have a non-circular cross-section, the distal end  112  of the cannula  104  is formed into the desired cross-section (step  1512 ). For example, where the distal end  112  of the cannula  104  is to have an oblong or oval cross-section, a flat plate of a predetermined thickness is placed inside of the tubing, and the distal end  112  is placed between two parallel plates that are brought together to produce the desired profile in the distal portion  112  and at the transition or ramped portion  208 . 
         [0046]    After shaping the distal end  112  of the cannula  104  at step  1512 , or after determining at step  1508  that the distal end  112  of the cannula  104  is to have a circular cross-section, the tip  112  is formed by plugging the tubing at the distal end  112  (step  1516 ). For example, plugging the tubing at the tip  112  may comprise welding a plug of metal into the interior diameter of the tubing at the tip. The most distal hole or holes  120  of the inlet  116  are then formed by drilling through the wall of tubing and through a portion of the proximal edge of the plug (step  1520 ). The holes  120  can also be formed using electrochemical means or electrical discharge techniques. By intersecting the proximal edge of the plug when drilling an inlet hole  120 , the creation of a blind pocket between the forward end of the cannula channel  204  and the inlet hole  120  is prevented. Instead, the most distal end of the channel  204  coincides with the most distal edge of the hole  120 . Moreover, in accordance with embodiments in which a pair of holes  120  are opposite one another, the ability to clean the forward extent of the channel  204  can be further facilitated. After forming the most distal holes  120 , a determination may be made as to whether additional holes  120  are to be included in the inlet  116  (step  1524 ). If additional holes are to be included in the inlet  116 , those additional holes may be formed (step  1528 ). The process for forming a cannula  104  may then end. 
         [0047]    As can be appreciated by one of skill in the art, other or alternative steps may be included in a process for forming a cannula  104 . Moreover, where the cannula is to include provisions for a mechanical coupler, for instance to provide additional means for securing the cannula  104  to the handle  108 , or in connection with embodiments incorporating a two-piece cannula  104 , additional features may be formed on the cannula components. In addition, additional features, such as flanges along a proximal portion of the cannula, to facilitate securing the cannula  104  within the receiving channel  212  of the handle  108 , or other such features can be formed. Moreover, additional features can be incorporated into the inlet  116 . For instance, the outer surface of the cannula  104  adjacent the holes  120  can be raised or lifted, forming a rasp, to facilitate breaking up tissue during tissue collection. Formation of the cannula  104  can also include coating the interior pathway  204  with a silicone material. By coating the interior pathway  204  with silicone, rough areas are smoothed, and there is less chemical and physical trauma to fat cells. A silicone coating can also facilitate approval of system components for medical use. In addition, the cannula  104  can be polished mechanically or electrochemically, and passivation treatment can be performed with nitric acid or other substances to rid the cannula  104  of metal dust and micro abrasions. A system  100  in accordance with embodiments of the disclosed invention may be provided as a durable and/or a disposable device. Moreover, components of the system  100  may be durable, while other components may be disposable. By providing a system  100  in which some or all of the components are disposable, a system  100  may be constructed less expensively than a comparable system  100  that is intended to be durable. 
         [0048]    Systems  100  in accordance with embodiments of the disclosed invention can also include features to increase the speed of fat or tissue harvest. Such features can include cannulas  104  that are relatively short in length (e.g., less than 17 inches), cannulas of relatively large diameter (e.g., up to 10 mm), the inclusion of a cannula air hole or air holes  1004 , holes  120  that are relatively small in diameter (e.g., less than 0.054 inches), inlet holes  120  that span up to 2 inches of the length of the cannula  104 , inlet holes  120  that are as numerous as possible, and holes  120  that are round, rather than oblong or other shapes. In addition, features can be incorporated that promote the survival of fat cells and adult stem cells can be incorporated. Such features can include inlet holes  120  that are relatively small (e.g., less than 0.054 inches), the provision of a substantially continuous interior pathway  204  that avoids or eliminates drop offs and pockets and in which the pathway  204  of the cannula  104  extends through the handle  108 , a handle  108  with a receiving channel  212  that is substantially continuous and that eliminates drop offs and pockets, inlet holes  120  with dull edges to reduce damage to cells, cannulas  104  that are relatively short (e.g., less than 5 cm), inlet holes  120  that are round to produce parcels of fat that are less likely to be damaged during transit through the system  100 , the inclusion of one or more air inlet holes  1004  to provide a cushion of air for fat parcels during passage through the system  100 , the option of a disposable system  100  or components of the system  100  to lessen the likelihood of infection, the inclusion of a silicon inner coating to smooth rough spots and decrease the chance of chemical or physical trauma to fat cell parcels, the provision of a closed system to reduce the introduction of ambient air and bacteria, viruses, dust or other contaminants with the air, and/or the elimination of blind pockets at the tip  114  of the cannula  104 . Still other of the disclosed features can be included to decrease the formation of ripples in the skin, such as flattening the dissecting end of the cannula  104  to an oval or a rectangle to reduce the cannula apex near the dermis. In still other aspects, a system  100  in accordance with embodiments of the disclosed invention can be produced economically, in that there is no cost for potting the cannula  104  in the handle  108 , the provision of embodiments that eliminate or reduce the need for Luer locks, screw or o-ring type connectors, or other connectors, and/or the provision of a handle  108  that can be used with different cannula  104  configurations. 
         [0049]    The foregoing discussion of the invention has been presented for purposes of illustration and description. Further, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, within the skill or knowledge of the relevant art, are within the scope of the present invention. The embodiments described hereinabove are further intended to explain the best mode presently known of practicing the invention and to enable others skilled in the art to utilize the invention in such or in other embodiments and with various modifications required by the particular application or use of the invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art.

Technology Category: a