Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2002-05-03
2004-04-06
Kennedy, Sharon (Department: 3762)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
Reexamination Certificate
active
06716194
ABSTRACT:
I. BACKGROUND OF THE INVENTION
This invention relates generally to surgical instruments, and, more particularly, to a surgical device for use in aspirating tissue and fluids from a patient.
Liposuction is a surgical procedure for altering the human form, specifically by removal of localized deposits of fat tissues that are unresponsive to diet or exercise. The procedure is also known as suction lipectomy, lipolysis, and more recently as body contour surgery or body sculpting surgery. It is most often performed by plastic surgeons, although dermatologists, gynecologists, and other surgical specialties also perform the procedure.
The procedure is typically accomplished by inserting a small diameter hollow cannula through an incision in the skin, applying a suction source to the end of the cannula that remains outside of the body, and forcing the working end of the cannula forward and backward in the layer of fatty tissue. The fatty tissue is torn, crushed, or avulsed, and is then aspirated through small openings along the sides of the hollow cannula near the tip and then through a length of suction tubing to a tissue canister placed in-line with the cannula and the suction source. The procedure may involve multiple incisions and many passes of the cannula in each incision to achieve the desired cosmetic effect for the patient.
A liposuction cannula is typically a small metal tube with a blunt, closed end at the tip. The blunt, closed end at the tip is intended to minimize damage to tissues as the device is thrust forward. Small openings along the sides of the cannula near the tip create passages between the tissue and the central lumen of the cannula, which is in fluid communication with a suction source, so that tissue and fluids can be aspirated. The suction causes the adipose tissue to be pulled into the openings along the sides of the cannula, and the blunt dissection provided by the surgeon's manipulation of the cannula tears the tissue. The fragments and released fluids are then aspirated through the openings along the sides of the cannula and then through the central lumen of the cannula. The liposuction procedure is referred to as a ‘closed’ procedure because the operative site about the tip of the cannula is not directly visualized during the procedure due to the small incision size and the length of the liposuction cannula, which results in the tip area's being buried inside the tissue.
When a cannula is placed into the fatty tissue through the small incision, a seal is created between the outer surface of the cannula about and along its length and the fatty tissue, preventing the flow of any ambient pressure fluid, such as air, to the operative site about the tip of the cannula. When suction is applied, there exists a level of vacuum inside the cannula at the operative site (the blunt tip area and the side openings) that pulls the tissue into the side openings, which is then torn with the motion of the cannula. Because the seal prevents the flow of any ambient pressure fluid or air to the operative site about the tip or the cannula, the pressure about the tip of the cannula quickly drops to the level of the vacuum of the suction source. The combination of the above-mentioned seal and the fact that the pressure at the operative site about the tip of the cannula has dropped to the level of vacuum of the suction source greatly reduces, if not completely eliminates, the surgeon's ability to remove tissue fragments and fluids from the operative site because the pressure differential between the operative site at the tip of the cannula and the suction source has been eliminated. Thus, tissue fragments and fluids move not at all or very slowly through the cannula and suction tubing. The tip of the cannula must be withdrawn from the patient to such an extent that the seal is broken and the tip and side openings are exposed to ambient air pressure to clear the cannula and suction line. This clearing process removes the tissues and fluids from the cannula and suction tubing and deposits them into the suction canister. At the same time the vacuum level in the suction canister, suction tubing, and cannula is significantly reduced because of the open connection to ambient air. When the cannula is re-inserted into the patient the suction pump begins to pull the air from the canister, suction tubing, and cannula until a good working vacuum is re-established and the system is again functional for aspirating tissue and fluids.
When tissue and fluids are present in the suction tubing they tend to group together and move through the tubing in ‘segments’. The segments most often completely fill the inner diameter of the suction tubing for some length and may be separated from each other by air bubbles. Any number of typical segments may be present in the suction tubing at any one time. This fact means that the suction pump and the cannula are not directly connected through a continuous air channel that can be evacuated by the suction pump, rather an ‘effective’ vacuum is applied to the cannula through the segments and the trapped air bubbles in the suction tubing. This fundamentally limits the vacuum available at the cannula because the trapped air bubbles act as ‘gas springs’ and expand under the action of the vacuum. The resistance to the movement of the viscous material, both tissue and fluids, in the suction line further reduces the effective vacuum available at the cannula. A long segment of tissue and fluid may have sufficient resistance to movement that the effective vacuum is nil and the cannula must be withdrawn from the patient and the tip exposed to ambient air in order for the segment to pass to the canister. The optimal situation is when the suction tubing is completely clear all the way from the canister to the cannula and a good working vacuum is present. This condition is only achievable for a short period of time with present cannula designs. As soon as viscous tissue and fluids enter the suction line the optimal situation is compromised.
Many patents disclose improvements and solutions for liposuction cannulae. U.S. Pat. No. 4,596,553 to Lee discloses a suction cannula with a guide bar attached to the cannula that is used to control the depth of the cannula in the tissue relative to the skin. U.S. Pat. No. 4,735,605 to Schwartz discloses a suction cannula with an outer tube with a longitudinal slot, and an inner tube with a spiral slot that is movable relative to the outer tube. U.S. Pat. No. 5,112,302 to Cucin has a suction cannula with a reciprocating means so that the cannula can be caused to reciprocate relative to the handle. U.S. Pat. Nos. 5,348,535 and 5,643,198, also to Cucin, have a suction cannula with a hollow outer cannula and a hollow inner cannula connected to a reciprocating means. The hollow inner cannula reciprocates within the hollow outer cannula so that tissue pulled into openings in the hollow outer cannula is sheared between the two cannulae. U.S. Pat. No. 5,181,907 to Becker has a tubular member with a plurality of longitudinally extending members projecting radially outward beyond the surface of the tubular member. U.S. Pat. No. 5,665,101 also to Becker has a method of cutting tissue with a rotary powered surgical instrument with an inner and an outer tube, both with cutting windows on the sides of the tubes. U.S. Pat. No. 5,569,178 to Henley has a source of rotary power, an outer tubing, and an inner tubing with flanges.
U.S. Pat. No. 5,013,300 to Williams has a single lumen cannula, a handle, a means to swivel the handle relative to the cannula, and a plurality of openings in the handle for controlling the suction forces applied to the cannula. The plurality of openings have an aggregate flow area approximately that of the flow area of the bore through the handle. The surgeon uses his or her thumb to uncover the openings to allow a relatively unrestricted flow of ambient air to clear the suction tube. At the same time this process eliminates the vacuum in the cannula. The surgeon then covers the openings to re-establish a vacuum
Cimino William W.
Geary Peter D.
Kennedy Sharon
Merchant & Gould P.C.
Sound Surgical Technologies LLC
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