WO2003045468A1

WO2003045468A1 - Handpiece for liposuction driven by ultrasound

Info

Publication number: WO2003045468A1
Application number: PCT/EP2002/013502
Authority: WO
Inventors: Zuzana Frank; Vladimir N. Khmelev; Michael Zisser
Original assignee: Tometric Ag Scweiz
Priority date: 2001-11-30
Filing date: 2002-11-29
Publication date: 2003-06-05
Also published as: DE10158725A1; AU2002352184A1

Abstract

The invention relates to a handpiece for liposuction driven by ultrasound comprising a cannula (2), connected to an ultrasound generator, with a proximal section (3) facing the ultrasound generator and a distal section (4). A pocket (6) is embodied in the free end of the distal section (4) for the generation of an inner circumferential surface (9).

Description

Handpiece for ultrasound-controlled liposuction

The invention relates to a handpiece for ultrasound-controlled liposuction with a cannula coupled to an ultrasound generator, which one

Ultrasonic generator facing proximal section and a distal section.

Liposuction methods have been developed in recent decades with which subcutaneous fat can be suctioned off, which has accumulated in certain regions of the body, for example on the hip or on the thighs, and which does not respond or does not respond well to diets or physical training. In liposuction procedures used as standard today, a cannula is inserted into the adipose tissue through an incision through the skin with one hand of the surgeon continuously moved back and forth while a negative pressure is applied to the cannula. The reciprocating movement of the cannula loosens parts of the adipose tissue and sucks it off through the cannula by means of the negative pressure, so that tubular cavities are created within the adipose tissue, the shape of which the surgeon has to continuously check with the other hand, while with one hand the The cannula is moved through the adipose tissue to balance the structures.

This liposuction procedure has a number of disadvantages in that the continued movement of the cannula through the adipose tissue can injure other body tissues or damage blood vessels. In addition, this liposuction procedure is physically very demanding for the surgeon, and this effort must be maintained over a long period of time in order to achieve averaging with regard to the formation of the tubular cavities by a large number of cannula movements, so as to give the cotton-like structure of the remaining adipose tissue to avoid under the skin. As an alternative to this widely used liposuction procedure, ultrasound-controlled liposuction has been developed, in which ultrasound is generated by means of an ultrasound generator, which facilitates the movement of the cannula through the fatty tissue, since the ultrasound accelerates and shreds the fat in the direction of the longitudinal axis of the cannula dispersed in the rinsing solution, whereby the heating of the fat also supports the dispersion and its subsequent suction. This light, gentle suction in conjunction with the fat liquefaction helps to avoid a shear effect and thus reduces damage to neighboring structures such as connective tissue, lymphatic and blood vessels. In general, ultrasound-controlled liposuction therefore results in less postoperative swelling and hematoma. The problem with ultrasound-controlled liposuction is that the dissolved fat cells heat up so quickly and so strongly that the skin can burn from the inside and skin transplants may be necessary. This disadvantage is so serious that, despite its other advantages, ultrasound-controlled liposuction is currently used only to a limited extent.

The invention has for its object to design a handpiece of the type mentioned in such a way that undesired overheating of the fatty tissue can be avoided.

This object is achieved in a handpiece of the type mentioned in the introduction in that a pocket is formed in the free end of the distal section to provide an inner peripheral surface.

This design has the advantage that a larger area is available on the distal section in order to deliver the ultrasound power to the fatty tissue, with an increase in the area both on the end face of the distal section and in its circumferential direction when the cannula is used widens in its distal section from the proximal section to its free end. The area given in the circumferential direction is inclined to the proximal section due to the expansion. You get thus on the one hand a directional radiation of the ultrasonic vibrations along the acoustic axis of the vibration system and on the other hand a radiation of the ultrasonic vibrations in the opposite direction at an angle to the acoustic axis in the volume to be processed. In both directions, intense hydrodynamic flows are created, which cut through the adipose tissue and simplify the movement of the cannula and support the dispersion of the fat in the rinsing solution. With this cannula a very effective use of energy takes place, so that compared to known systems the electrical power can be reduced by an order of magnitude with a comparable local effect of the ultrasound. The hydrodynamic currents promote the rapid distribution of the heat and ensure an exchange of the liquefied fat near the surface of the distal section. These hydrodynamic flows prevent cavitation bubbles on the surface of the cannula, which is associated with a stabilization of the radiation resistance and facilitates the work of the ultrasound generator. Loads on the distal section due to cavitation and the associated destruction of the surface are reduced.

It is preferred if the inner circumferential surface of the pocket extends inclined to the longitudinal axis of the cannula with the circumference growing towards the free end of the distal section. With this design, a focal effect occurs that concentrates the ultrasonic energy forward and generates the hydrodynamic flows particularly effectively. It is furthermore provided that the pocket is arranged on the end face of the distal section with an opening cross section which is larger than the cross section of the proximal section. This embodiment is characterized first of all by its symmetrical structure of the distal section, which in particular enables a uniform flow. In addition, there is a further enlargement of the area usable for radiation on the front side, since the distal-facing inner circumferential surfaces located in the interior of the cannula receive direct contact with the surrounding external medium. This advantage is particularly pronounced when the opening cross section of the pocket corresponds to the cross section of the distal section at its free end. With this design, the maximum magnification is

Radiation area given, from a surface that corresponds to the cross section of the distal portion at its free end to a surface that is given by the entire circumferential inner surface.

It has proven to be advantageous if the inner surface of the distal section corresponds to the surface of a truncated cone. In these embodiments, the ultrasonic vibrations are focused at a distance from the free end of the distal section, so that a large part of the energy delivered can be distributed undisturbed by the cannula into the external medium. The onset of hydrodynamic flow is particularly strongly directed forward and sweeps away the adipose tissue that is heated up. This also occurs

Flow component that is exactly opposite to the acoustic axis of the system, that is directed towards the pocket to replace the outflowing medium. This shape gives the distal section the properties of a pump and sucks the liquid through the pocket into the cannula, so that it is advantageous if the pocket is connected to a suction channel formed in the cannula and is designed as a suction opening.

Different designs of the distal section are suitable for different applications. It is provided that the inner circumferential surface is formed by a plurality of truncated cones arranged one behind the other, the inner angle of which becomes larger towards the free end. In addition, there is the possibility that two of the truncated cones are separated by a section of the inner circumferential surface of constant diameter. As an alternative, it is provided that the inner circumferential surface of the distal section corresponds to the surface of a hemisphere or a paraboloid.

It is also advantageous if the outer surface of the distal section corresponds to the surface of a truncated cone or a hemisphere or a paraboloid. The shape of the outer surface is chosen so that it is as small as possible in relation to the enclosed volume in order to keep the loss of energy that is not emitted over the inner peripheral surface small, the shape of the outer surface being independent of the Choice of the shape of the inner surface is. So it is possible to give the inner surface the shape of a truncated cone and the outer surface the shape of a paraboloid in order to avoid a too sharp focus along the acoustic axis and at the same time against the acoustic axis in the direction of the proximal section, not only in one Direction to generate, but in the directions perpendicular to the paraboloid. Again, there are additional shapes for different applications, namely that the outer surface to the free end of the distal portion from the surface of a

Truncated cone merges into a cylindrical surface, or that the outer surface of the distal section merges from the surface of an expanding truncated cone into a surface tapering towards the free end. The end face of the distal section is preferably rounded.

To better prevent overheating, the cannula, preferably its distal section, is assigned a thermal sensor connected to an evaluation unit, which is formed by a Pt-100 element to save space and is part of a thermal safety system with which the temperature in the operating field can be precisely monitored ,

It is advantageous if the opening angle of the bag is less than 90 ° and greater than 0 °, the choice of the optimal opening angle depending on the desired area of use, that is to say it can be varied depending on whether the cannula is to be used in relatively thick fatty tissue or rather in thin layers of fat, such as those found on the face or on the upper arms. The opening angle correlates with the range of the resulting hydrodynamic flow, since the focus range also changes, which in turn

Has repercussions on the hydrodynamically generated suction power. It is also advantageous if the inner angle of the outer surface of the distal section is less than 90 ° and greater than 0 °. In view of the universal replaceability of the handpiece, it is advantageous if the distal section is detachably connected to the proximal section, since this gives the possibility that distal sections can be used which are adapted to the anatomical conditions of the desired area of application and which can be used with regard to the Shaping and the inner and outer surface as well as the

Differentiate the opening angle and the inside angle. In order to enable a uniform flow with as little turbulence as possible, the pocket has rounded edges, so that, as a result, it is also ensured in this area that air molecules or cavitation bubbles do not adhere to the

Surface of the distal section arise, but are transported away from this.

A particularly preferred embodiment of the invention is characterized in that the

Handpiece arranged the ultrasonic generator and connected to the cannula via an ultrasonic concentrator as a connecting element to the vibration system. This embodiment is characterized by a particularly compact design, in which the transmission losses from the ultrasound generator via the cannula into the fatty tissue are minimized, since the transmission lengths can also be kept very short.

In the context of the invention, it is also possible that the inner peripheral surface of the pocket for focusing the ultrasonic energy inside the pocket and / or outside the pocket and / or in the plane of the End face (8) is shaped, with this design influencing the effect of the handpiece, which is rather soft with a focus inside, while a focus outside the cannula causes a hard cutting effect. It is possible, for example by axially staggering the shape of the inner circumferential surface, to combine several focal points with their typical effects.

As part of the thermal safety system, there is a leading end to the cannula with one

Connected liquid reservoir blind hole, which can be flushed with a coolant to actively dissipate the heat generated and better to monitor and control the temperature in the operating field.

In the following the invention is explained in more detail using exemplary embodiments shown in the drawing; show it:

1 shows a longitudinal section through a schematically illustrated handpiece with attached cannula,

2 shows a longitudinal section through the distal section of a cannula in a further embodiment,

3 a representation corresponding to FIG. 2 of a further embodiment,

4 a representation corresponding to FIG. 2 of a further embodiment, 5 a representation corresponding to FIG. 2 of a further embodiment,

6 a representation corresponding to FIG. 2 of a further embodiment,

7 shows a representation corresponding to FIG. 2 of a further embodiment,

8 a representation corresponding to FIG. 2 of a further embodiment,

Fig. 9 is a representation corresponding to FIG. 2 of a further embodiment, and

Fig. 10 is a representation corresponding to Fig. 1

Handpiece with a trained in the cannula

A blind hole.

The handpiece 1 shown in FIG. 1 is intended for ultrasound-controlled liposuction and has an ultrasound generator arranged inside a housing of the handpiece 1, which is formed, for example, by a piezoelectric transmission motor in the usual manner and not shown in detail in the drawing

Can produce ultrasonic vibrations in the range between 6 and 60 kHz, preferably in the range between 22 and 25 kHz. The handpiece 1 further consists of a cannula 2 connected to the ultrasound generator via an ultrasound concentrator as a connecting element to the vibration system, which has a proximal section 3 facing the ultrasound generator and a distal section 4 The cannula 2 widens in its distal section 4 from the proximal section 3 to its free end 5. To provide an inner circumferential surface 9, the distal section 4 also has a pocket 6, which in FIGS. 1-9 is connected to a suction channel 7 formed in the cannula 2 and is arranged on the end face 8 of the distal section 4. The opening cross section of the pocket 6 is larger than the cross section of the substantially cylindrical proximal section 3 and corresponds to that in FIG

1 shows the cross-section of the distal section 4 at its free end 5. The end face 8 of the distal section 4 is rounded, to which a thermal sensor connected to an evaluation unit, in particular a Pt-100 element, is assigned. A recess 12 is formed in the end face 8 of the distal section 4 from FIGS. 6 and 7 in the circumferential direction.

The inner circumferential surface 9 of the pocket 6 extends inclined to the longitudinal axis of the cannula 2 with the circumference growing towards the free end of the distal section 4. In the exemplary embodiments shown, the inner surface 9 of the distal section 4 is shaped in accordance with the surface of a truncated cone, but can also have the surface of a hemisphere (FIG. 8) or a paraboloid (FIG. 9). 4, several, namely two truncated cones are arranged one behind the other, the inside angle of which increases toward the free end. 5 shows an example in which two of the

Truncated cones are separated by a section of the inner circumferential surface of constant diameter. The opening angle of the pocket 6 is less than 90 ° and greater than 0 °.

The outer surface 10 of the distal section 4 in the exemplary embodiments shown in FIGS. 1 and 2 is again shaped in accordance with the surface of a truncated cone, with an internal angle which lies in the interval between 0 ° and 90 °. 2, the outer surface merges with the free end of the distal section from the surface of a truncated cone into a cylindrical surface. 7 therefore shows that the outer surface of the distal section merges from the surface of an expanding truncated cone into a surface which tapers towards the free end.

The distal section 4 is detachably connected to the proximal section 3, so it can be replaced.

From the drawing it can also be seen that the cannula 2 is encased by a protective sheath 11, which consists of elastic material and is connected to a liquid reservoir via a liquid line. The material for the protective cover 11 is selected so that it has a large positive coefficient of thermal expansion at the operating temperature, that is to say approximately at the body temperature of a person. Conduit channels for the liquid are formed in the inner surface of the protective sheath 11 and / or in the outer surface of the cannula 2, the cross section of the conduit channels being matched to the required delivery rate. In order to achieve an extension of the conduit channels at the given length of the cannula, these are in one Helix around the longitudinal axis of the cannula 2 out.

The protective sheath 11 is detachably connected to the cannula 2 and consists of a material with properties similar to latex, with Teflon or, with regard to latex allergies to possible patients, latex-free material, known under the name Lastrokran, being known as further suitable materials. The cannula 2 itself can also be formed from flexible glass fibers, as are known from endoscopes.

Fig. 10 shows an embodiment in which a blind hole connected to the liquid reservoir is formed in the cannula as part of the thermal security system.

The use of the handpiece 1 according to the invention is briefly described below, in which the ultrasound generator arranged in the handpiece 1 is generally connected to an external energy source, while the suction channel 7 leading to the pocket 6 leads to a storage vessel in the cannula 2. The protective cover 11 is connected to the liquid reservoir, and a saline solution can be used as the liquid, for example, which is supplied to the protective cover 11 by a pump.

After the surgeon has made an incision through the patient's skin, the cannula 2 of the handpiece 1 can be inserted into the subcutaneous fat tissue into which the saline solution can be flushed in by the pump. Subsequently or simultaneously, it is possible to dispense and melt the adipose tissue by introducing ultrasound, due to the shape of the distal section 4 Hydrodynamic flows are generated, which flow on the one hand from the end face 8 and the inner surface 9 of the distal section 4, on the other hand from the outer surface 10 directed towards the proximal section 3 from the cannula 2 and a large-scale dissipation of the

Promote warmth. This is also associated with the avoidance of cavitation bubbles on the outer surface 10 of the cannula 2, which could destroy the material. Due to the hydrodynamic currents, in addition to the dissipation of the energy introduced into the fatty tissue by the ultrasound generator by means of the cannula 2, cooling of the cannula 2 is also connected, which is additionally promoted by the fact that the liquid flows through the space formed between the protective cover 11 and the cannula 2 is promoted. If particularly strong heating occurs locally, the protective cover 11 can also expand locally due to its suitably selected material properties, so that a larger amount of liquid accumulates there and ensures better cooling. The liquid can be sucked through the pocket 6 at least partially together with the fatty tissue.

Claims

Claims:

1. Handpiece for ultrasound-controlled liposuction with one coupled to an ultrasound generator

Cannula (2) which has a proximal section (3) facing the ultrasound generator and a distal section (4), characterized in that in the free end of the distal section to provide a

Inner circumferential surface (9) a pocket (6) is formed.

2. Handpiece according to claim 1, characterized in that the cannula (2) widens in its distal section (4) from the proximal section (3) to its free end (5).

3. Handpiece according to claim 1 or 2, characterized in that the inner peripheral surface of the pocket (6) inclined to the longitudinal axis of the cannula (2) extends with the free end of the distal portion (4) increasing circumference.

4. Handpiece according to one of claims 1 to 3, characterized in that the pocket (6) on the end face (8) of the distal section (4) is arranged with an opening cross section which is larger than the cross section of the proximal section (3) ,

Handpiece according to Claim 4, characterized in that the opening cross section of the pocket (6) corresponds to the cross section of the distal section (4) at its free end (5) corresponds.

6. Handpiece according to one of claims 1 to 5, characterized in that the inner peripheral surface (9) of the distal section (4) corresponds to the flat surface of a truncated cone.

7. Handpiece according to claim 6, characterized in that the inner circumferential surface (9) is formed by a plurality of truncated cones arranged one behind the other, the inner angles of which are larger towards the free end.

8. Handpiece according to claim 7, characterized in that two of the truncated cones are separated by a portion of the inner circumferential surface of constant diameter.

9. Handpiece according to one of claims 1 to 5, characterized in that the inner circumferential surface (9) of the distal portion (4) corresponds to the flat of a hemisphere.

10. Handpiece according to one of claims 1 to 5, characterized in that the inner peripheral surface (9) of the distal portion (4) corresponds to the flat surface of a paraboloid.

11. Handpiece according to one of claims 1 to 10, characterized in that the outer surface (10) of the distal portion (4) in the region of the pocket of the

Area of a truncated cone corresponds to a partial sphere or a paraboloid.

12. Handpiece according to one of claims 1 to 10, characterized in that the outer surface (10) of the distal portion (4) in the region of the pocket corresponds to the surface of a truncated cone.

13. Handpiece according to claim 12, characterized in that the outer surface (10) to the free end of the distal portion (4) merges from the surface of a truncated cone into a cylindrical surface.

14. Handpiece according to claim 12, characterized in that the outer surface (10) of the distal portion (4) from the surface of an expanding truncated cone in a tapering towards the free end. Surface merges.

15. Handpiece according to one of claims 1 to 14, characterized in that the end face (8) of the distal section (4) is rounded.

16. Handpiece according to one of claims 1 to 15, characterized in that a recess (12) is formed in the circumferential direction in the end face (8) of the distal section (4).

17. Handpiece according to one of claims 1 to 16, characterized in that the pocket (6) is connected to a suction channel (7) formed in the cannula (2) and is designed as a suction opening.

18. Handpiece according to one of claims 1 to 17, characterized in that the cannula (2), preferably its distal section (4), one with an evaluation unit connected thermal sensor is assigned.

19. Handpiece according to claim 18, characterized in that the thermal sensor is formed by a Pt-100 element.

20. Handpiece according to one of claims 1 to 19, characterized in that the opening angle 1 of the pocket (6) is less than 90 ° and greater than 0 °.

21. Handpiece according to one of claims 1 to 11, characterized in that the inner angle of the outer surface (10) of the distal portion (4) is less than 90 ° and greater than 0 °.

22. Handpiece according to one of claims 1 to 21, characterized in that the distal section (4) is detachably connected to the proximal section (3).

23. Handpiece according to one of claims 1 to 22, characterized in that the ultrasonic generator is arranged in a housing of the handpiece (1) and is connected to the cannula (2) via an ultrasonic concentrator as a connecting element to the oscillation system.

24. Handpiece according to one of claims 1 to 23, characterized in that the inner peripheral surface (9) of the pocket (6) for focusing the ultrasonic energy inside the pocket (6) and / or outside of the

Pocket (6) and / or in the plane of the end face (8) is formed.

5. Handpiece according to one of claims 1 to 26, characterized in that in the cannula (2) leading to its free end (5) leading to a liquid reservoir blind hole (13) is formed.