a cannula and handle system 100 in accordance with embodiments of the disclosed invention is illustrated in elevation in fig1 . 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 . 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 . fig2 illustrates the system 100 of fig1 in cross section . as shown in fig2 , 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 . fig2 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 fig6 a ), and a round cross - section between a proximal edge of the shoulder 208 and the outlet 128 ( see fig6 b ). 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 . in general , the distal portion of the receiving channel 212 can feature an oval cross - section ( see fig7 a ) between a tapered or transition portion 220 ( see fig7 b ), 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 fig7 c ) 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 fig6 a ) 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 fig3 , 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 . fig4 is a cross - section of the cannula 104 of fig1 - 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 fig6 a . the proximal portion 124 of the cannula 104 , including at section line b - b , has a circular transverse cross - section as illustrated in fig6 b . a cross - section of this same cannula in plan view is illustrated in fig5 . the cannula 104 illustrated in fig1 - 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 fig6 ) 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 fig6 ). 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 . fig8 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 fig1 - 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 . 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 fig1 in elevation , and in fig1 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 fig1 ). 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 . the cannula illustrated in fig1 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 fig1 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 . the cannulas 104 illustrated in fig1 - 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 fig1 , 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 . fig1 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 . with reference now to fig1 , 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 . 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 . 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 . 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 . 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 .
cannula and handle systems and cannulas having substantially continuous interior pathways or channels are provided . the interior pathway may extend from the inlet to the cannula to the outlet , such that tissue collected at the inlet is carried to the outlet without contacting other components . moreover , the substantially continuous nature of the interior pathway , with an absence of drop - offs , blind pockets or other discontinuities , facilitates cleaning . in addition , inlet holes are sized to promote the transfer of tissue through the channel to the outlet , and to the avoidance of damaging collected tissue .