Patent Application
20130072912
Cannulas are surgical instruments, generally formed as tubes, used for delivery or removal of fluid and the like from a body. In cosmetic surgery, a cannula can be used to harvest fat or other tissue, and/or to insert bulk fillers. A cannula with holes for fat harvesting has been proposed, as described for example in U.S. Pat. No. 5,817,050, the entire content of which is hereby incorporated by reference.
Harvesting cannulas of the prior art focus on vacuum forces. There remains a need for improved harvesting cannulas.
A rasping cannula uses a variety of cutting surfaces to augment fat and tissue extraction in cosmetic surgical procedures. In one aspect, a cannula may have a number of holes with curved cutting edges. In another aspect, the tip of a cannula may be curved. In this manner, lateral movement of the cannula excises tissue such as fat for faster, more effective removal.
The invention and the following detailed description of certain embodiments thereof may be understood by reference to the following figures:
All documents mentioned herein are hereby incorporated in their entirety by reference. References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context. Thus the term “or” should generally be understood to mean “and/or” and so forth.
Disclosed herein are cannulas for use in cosmetic surgical procedures such as liposuction or other fat harvesting. However it will be understood that the invention disclosed herein is not so limited, and the inventive concept may be adapted to other tissue harvesting and/or extraction procedures.
The proximal end 104 may include any suitable structure for manipulating the cannula 100 or coupling the cannula 100 to a trocar or other instrument. The proximal end 104 may also be coupled by a tube or the like to a vacuum source 110 in fluid communication with an interior of the body 102 for applying vacuum through the body 102 to harvest fat or other tissue through the cannula 100.
The distal end 106 may include an insertion tip 108, which may include an opening and a cutting edge to cut fat or other tissue as the body 102 is inserted into a surgical site.
The cannula 100 may also include a protective sheath 112 configured to slide along the body 102 or otherwise positionable to cover various cutting edges of the cannula 100 in order to controllably expose cutting edges of one or more slits and/or the insertion tip 108. In this manner, the rasping action of the cannula 100 may be selectively deployed at a time and in a location along the body 102 where cutting of fat or other tissue is desired by a user.
A plurality of slits 206 may be provided so that tissue such as fat can be vacuum-extracted along the length of the body 202. Each slit 206 may provide a passage from an exterior of the body 202 to the open interior 208, along with a cutting edge that extends on a perimeter thereof that is elevated outside the body 202 (e.g., away from the open interior 208 and toward the exterior) in order to present a cutting surface that can be used to cut tissue with a corresponding movement of the body 202. In general, a variety of arrangements, shapes, and sizes of slits may be provided, consistent with use in a forward cutting motion of the cannula 200 (i.e., toward the insertion tip), a backward cutting motion (i.e., toward the proximal end), and/or a rotational cutting motion (i.e. rotationally about the axis 204). The cutting edges of the slits 206 may thus be generally oriented to cut tissue in a single direction of motion of the body 202, or in multiple directions.
In one aspect, the cutting edge of each one of the plurality of slits 206 may be oriented to cut tissue in one direction of movement along the axis 204 of the body 202, such as a movement along the axis 204 from the proximal end toward the insertion tip (forward motion) or a movement from the insertion tip toward the proximal end (backward motion) or a bidirectionally upon movement in either direction along the axis (e.g. back and forth, or away from and toward the insertion tip). In another aspect, the cutting edge of each one of the plurality of slits 206 may be oriented to cut tissue upon rotation of the body 202 about the axis 204, which may similarly be (rotationally) one directional or two directional.
A variety of sizes may be used. For example, each slit 206 may be about 1.5 mm along a short (or ‘minor’) axis and about 2.5 mm along a long (or ‘major’) axis, or any similar dimensions for which the major axis is substantially greater than the minor axis. Any number of slits may be provided.
A variety of arrangements may also be used. In one aspect, the slits 206 may wrap substantially completely around a circumference of the body 202. In another aspect, the slits 206 may wrap around about two hundred forty degrees of the body 202, or some other amount that provides a non-harvesting surface so that the cannula 200 can be used as a one-side or directional harvesting device. Similarly, the slits 206 may be oriented with a major axis oriented or angled about forty five degrees off the axis 204 of the body. Some slits may have a major axis oriented or angled about ninety degrees off the major axis of some other ones of the slits, as generally illustrated in
The shapes of the slits 206 may also vary. For example, while generally oval slits are illustrated, the slits 206 may be circles, polygons, or other shapes, the emphasis being on the direction and arrangement of cutting surfaces presented to tissue as the body moves 202 within tissue rather than the shape of the passage formed into the interior 208 of the body 202. Thus it will be more generally understood that while a specific arrangement of slits is illustrated, different numbers, shapes, and orientations of slits, holes, or the like with cutting edges may also or instead be used with satisfactory results.
A cutting edge 310 for the slit 300 may be a curved cutting edge forming a sharp, protruding ridge above the surface of the body 308 (the surface of the body illustrated where it spans the slit 300 by a dashed line 312) so that the cutting edge stands up somewhat off the otherwise cylindrical exterior surface of the body 308. This configuration is conveniently machinable to a sharp edge in stainless steel or other biocompatible surgical materials; however it will be understood that any other shape of cutting edge that extends above the surface of the body 308 may also or instead be used. Similarly, the cutting edge 310 may lie in the plane of the surface, which generally provides a less aggressive cutting action that may be advantages in certain applications.
In general, tissue excised from a surgical site by the cutting edge 310 may be further urged toward the interior 306 of the body 308 by the beveled interior surfaces of the slit 300 which, in conjunction with reverse pressure from a vacuum source, can effectively withdraw harvested fat from the site and out of the cannula.
The insertion tip 406 may include an opening 410 coupled to an open interior of the body 402 through which fat or other tissue can be withdrawn. The cutting edge 404 may be on a perimeter of the opening 410, and may extend entirely around the perimeter or a portion thereof.
As with the cutting edges of the slits discussed above, different positions and angles for the cutting edge 404 may be employed according to a desired aggressiveness for the cutting action. For example, the cutting edge may actually be recessed such that the leading edge of the cutting edge is aligned with the interior surface of the body 102. Or the leading edge may be machined or otherwise formed into a location between the interior and exterior surface of the body 102. More generally, any configuration providing an edge suitable for cutting tissue may be used for the cutting edge as contemplated herein.
While particular embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes and modifications in form and details may be made therein without departing from the spirit and scope of this disclosure and are intended to form a part of the invention as defined by the following claims, which are to be interpreted in the broadest sense allowable by law.
This application claims the benefit of U.S. App. No. 61/536,174 filed on Sep. 19, 2011, the entire content of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61536174 | Sep 2011 | US |
