Surgery – Means for introducing or removing material from body for... – With means for cutting – scarifying – or vibrating tissue
Reexamination Certificate
1999-12-09
2003-10-28
Kennedy, Sharon (Department: 3762)
Surgery
Means for introducing or removing material from body for...
With means for cutting, scarifying, or vibrating tissue
C604S902000, C606S171000
Reexamination Certificate
active
06638238
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a liposuction apparatus and method. More particularly, this invention relates to a liposuction apparatus optionally having a sonic or ultrasonic source with an axial lumen passage in which the shaft can be made to reciprocate in a non-rectilinear fashion. The apparatus and method may also contain the concomitant use of rectilinear reciprocation motion in addition to ultrasonic motion or energy along the shaft of said device.
2. Description of the Prior Art
Liposuction, which literally means “fat suction”, is a technique to remove intact fat cells, fat globules, fatty fluids or fatty debris from the body by means of teasing, pulling, scraping, sonication, suction and/or pressing out the debris. Liposuction can be used to reduce the volume of fat in many regions of the body, but liposuction is particularly effective in such areas as the thighs and the abdomen where fat is less responsive to diet and exercise. Liposuction, performed as an elective operation, is one of the most common surgeries performed in the world.
There are now several main forms of liposuction used by surgeons to extract fat. Each of these modalities varies in its necessity or usefulness, depending upon the area of the body being treated, the amount of fibrous tissue which is mixed in with the fat to be treated, the number of times the fat has been previously suctioned (which usually increases the fibrous and resistant nature of the fat), and the genetic makeup of the individual patient (African-American and Mediterranean ancestry patients and males usually have more fibrous fat). Herein follow some of the condensed benefits and more expanded upon drawbacks of each modality so as to differentiate our proposed devices from the prior art.
In traditional liposuction, a single lumen cannula shaft, attached to a handle, is pushed by a surgeon through skin entrance sites into the target fat in a spoke-wheel or radial fashion. Unfortunately, chronic and acute stress on the surgeon's elbow and shoulder can fatigue the surgeon, thus reducing the reproducibility of the result between the patient's right and left sides, and sometimes making for a less than optimal result. When a liposuction cannula passes through the target tissue, it tends to suck out or traumatize a diameter of fat that is related to the diameter of the shaft of the cannula. Ideally, one would use the smallest diameter shaft possible to reduce penetration injuries. Unfortunately, liposuction would take excessive time to perform with ultra-small (less than 2 mm) cannulas. Some surgeons utilize small cannulas that vary on the size of syringe needles. This work takes numerous hours to perform and is impractical for the average surgeon with typical time and anesthetic constraints. Additionally, the performance of numerus liposuction procedures and the necessity to move the surgeon's arm back and forth so many times within a unit period of time has led to surgeons having physical conditions similar to tennis elbow and arthritis of the involved joints. Most surgeons thus use larger single lumen cannula shafts, up to 4 to 6 mm in diameter. Unfortunately, these larger diameter cannulas often leave noticeably large waves behind in the patient's target fat area and surface skin resulting in an unpleasant, non-uniform appearance to the skin.
In a review by Weber et al, Reinforced Swan-Neck, Flexible Shaft, Beveled Liposuction Cannulas (The American Journal of Cosmetic Surgery) 16(1): 41-47, 1999, dynamics of liposuction cannula tips were discussed. Although smaller tips and shaft diameters require less energy from the surgeon to penetrate fibrous fat, less fat per unit time is removed. Larger diameter cannulas remove fat faster, but require greater effort and tissue trauma. It is difficult to find a happy medium, although sometimes the choice of a cannula tip can reduce the exertion necessary to pass through fibrous fat. (See above referenced Weber et al, American Journal of Cosmetic Surgery.)
Ultrasonic liposuction cannulas were developed by Parisi et al in the late 1980's and patented under the patents “Liposuction Procedure With Ultrasonic Probe”, U.S. Pat No. 4,886,791 and “Ultrasonic Probe”, U.S. Pat. No.
4,861,332 (1988
). Parisi claims that the ultrasonic process “melts” fat. Only if the word “melt” is used extremely loosely and re-defined is this true. Fat stored in the body may be encapsulated in cells and is not truly solid to any degree. The ultrasonic cannula uses water as a coupling medium in order to break apart fat cells and fat globules, thus releasing fat from the aforementioned cells and fibrous tissues which provide support and structure to the human fat. Parisi saw early on that the tremendous heat generated by the ultrasonic liposuction cannula could be detrimental to the patient and therefore requires significant cooling measures. The material which follows will demonstrate three generations of ultrasonic liposuction cannulas based upon the Parisi patents, which still do not provide an adequate solution.
Three (3) Generations of Ultrasonic Liposuction
The newest (third generation) ultrasonic liposuction cannula is basically cooled along the length of the cannula shaft by an outer metal sleeve that almost covers the vibrating tip. Sterile cooling water passes between the hot inner vibrating shaft and the outer metal sleeve. The cooling water exits at the tip of the cannula as a “bubble” of water. Disadvantageously, the metal cooling sleeve leaves only a fraction of an inch of vibrating shaft (tip) exposed to the patient's tissue. This design change is alleged to reduce the tendency for thermal burns. A major drawback for the third generation of ultrasonic cannulas is that there is incomplete suction of the sonicated (broken and foamy) fat out of the patient's tissues. The broken down fat remaining in the patient must be crudely pressed out with rollers, suctioned out with old-fashioned cannulas or left to be “absorbed” inside the patient's body. The long term effects of leaving foamy fat and broken down fat cells behind in the body have not been determinated. For example, degraded fat may cause more fibrosis of the treated areas, or the liver or vessels may be damaged by fatty infiltration due to overload.
The third generation still suffers the possibility of causing thermal burns wherein a hot cannula tip strikes or harms the skin. Another problem with ultrasonic liposuction is that the tip can become extremely hot when impacting a dense bodily structure if the ultrasonic cannula is moving too slowly.
Some of the disadvantages of ultrasonic liposuction, no matter what generation of cannula is used, are currently unknown to many patients. Ineffectively, surgeons use rolling pins to “squish out” the remainder of the liquefied fat out of the patients. This means that the current ultrasonic cannulas are suction-inefficient, perhaps leaving up to one-half of the sonicated fat behind. Current cannulas do not have holes large enough or exposed enough to completely suction-up the fat that is sonicated and liquefied. Fatty acids are a known source of inflammation in the human body and may cause the body to lay down scar tissue and other unwanted reactions. Additionally, the tunnels and unsonicated liquefied oils and their by-products likely contribute to the formation of seromas (fluid ball collections) so commonly seen with ultrasonic liposuction procedures. Using rollers is not an optimal way to remove fat and is only partially successful. Current ultrasonic liposuction cannulas cannot bend sufficiently and still vibrate (sonicate) the desired target structures. Early generations of ultrasonic liposuction cannulas, which are still currently in use in many offices throughout the United States, incorporate large “protectors” that are screwed into the patient's skin to protect the entrance sites from burns. These “protectors” make for even larger scars at the entrance wounds. Another disadvantage of the third generation lipos
Da Silva Luiz B.
Everett Matthew J.
Kolster Alwin H.
Visuri Steven R.
Weber Paul J.
Kennedy Sharon
Staggs Michael C.
The Regents of the University of California
Thompson Alan H.
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