WO1999033665A1

WO1999033665A1 - Ultrasonic liposuction probe

Info

Publication number: WO1999033665A1
Application number: PCT/US1998/026099
Authority: WO
Inventors: Vaclav O. Podany; Stephen Dimatteo; Scott C. Kellog
Original assignee: Mentor Corporation
Priority date: 1997-12-31
Filing date: 1998-12-09
Publication date: 1999-07-08
Also published as: WO1999033665A8

Abstract

A probe for ultrasonic tissue treatment (such as liposuction) includes a body having a wall defining a lumen. A thickness of the wall decreases in a distal direction such that the lumen increases in cross section in the distal direction. The wall tapers to a smaller thickness in the distal direction. The wall steps down to a smaller thickness in the distal direction. The probe is cylindrical and an outer diameter of the probe remains constant while the thickness of the wall decreases.

Description

ULTRASONIC LIPOSUCTION PROBE

Background of the Invention This invention relates to a probe for generating ultrasonic vibrations to treat tissue, for example, liposuction of adipose tissue.

Ultrasonic assisted liposuction is typically conducted using an ultrasonically vibrating probe extending through a portal to a surgical site. The surgeon carefully manipulates the ultrasonically vibrating probe to treat tissue to be removed while avoiding other bodily tissue such as muscles, body organs and blood vessels. It is known to step down or taper distally the outer diameter of an ultrasonic probe to provide for amplification of the ultrasonic vibrations. Summary of the Invention

In general, according to one aspect of the invention, a probe for ultrasonic tissue treatment includes a body having a wall defining a lumen. A thickness of the wall decreases in a distal direction such that the lumen increases in cross-section in the distal direction.

Embodiments of this aspect of the invention may include one or more of the following features. The wall tapers to a smaller thickness in the distal direction. The wall steps down to a smaller thickness in the distal direction. The wall steps down in the vicinity of a node, in the vicinity of a plurality of nodes, and distally of a distal most node.

The probe is cylindrical and an outer diameter of the probe remains constant while the thickness of the wall decreases. A length of the body over which the wall thickness decreases is a minority portion of an overall length of the body. A majority portion of the overall length of the body has a constant wall thickness. In a preferred embodiment, the probe is configured to perform liposuction. An opening in fluid communication with the lumen is defined at a distal tip of the probe. A cap is mounted on the distal tip for covering the opening at the distal tip. An opening extends through the probe wall. The opening extends radially from a longitudinal extent of the lumen. A plurality of openings extends through the probe wall. The plurality of openings are equally spaced about the body. The body is cylindrical and the plurality of openings are equally spaced about a circumference of the body.

According to another aspect of the invention, a method of amplifying ultrasonic vibrations includes applying ultrasonic vibrations to a proximal end of an ultrasonic probe, and amplifying the ultrasonic vibrations by decreasing a thickness of a wall of the ultrasonic probe in a distal direction such that a lumen defined by the wall increases in cross-section in the distal direction. Among other advantages, the ultrasonic probe of the present invention provides amplification without requiring a change in the profile of the outer diameter of the probe. The smooth outer profile helps minimize the chances of soft tissue being torn by exposed edges on the outer surface of the probe.

Other features and advantages of the invention will become apparent from the following detailed description and from the claims.

Brief Description of the Drawings FIG. 1 is an illustration of an ultrasonic probe according to the invention.

FIG. 2 is a cross^sectional side view of a distal region of the probe of FIG. 1.

FIG. 3A is a partially cut-away side view of an additional embodiment of an ultrasonic probe; FIG. 3B is an exploded view of region 3B of the probe of FIG. 3A; FIG. 3C is an exploded view of region 3C of the probe of FIG. 3A; and FIG. 3D is an exploded view of region 3D of the probe of FIG. 3A. Detailed Description of the Preferred Embodiment

Referring to FIGS. 1 and 2, an ultrasonic probe 10 for removing adipose tissue from a human or other animal body includes a distal region 12, a mid region 16, and a proximal end 14. Proximal end 14 is configured to releasably engage with a handpiece 50 of an ultrasonic liposuction system 52 for generating ultrasonic vibrational energy. An ultrasonic liposuction system is described, for example, in Podany et al., titled ULTRASONIC ASSISTED LIPOSUCTION SYSTEM, filed November 7, 1997, incorporated by reference herein. Pressure waves produced by ultrasonic vibrations received by proximal end 14 are transmitted from distal region 12 to a surgical site. A step down 40 between proximal end 14 and mid region 16 acts to amplify the ultrasonic vibrations received by proximal end 14.

Distal region 12 of probe 10 further acts to amplify the amplitude of the ultrasonic vibrations. A probe wall 8 has a tapered wall portion 20 extending proximally from distal region 12 to a transition plane 24. Tapered wall portion 20 is formed by decreasing the thickness of wall 8 in the distal direction while maintaining the outer diameter of wall 8. A lumen 18 defined by probe wall 8 thus increases in cross-section as it extends distally from transition plane 24 toward a distal end 7 of probe 10. Lumen 18 extends from distal region 12 to proximal end 14.

Tapered wall portion 20 serves as a Gaussian-type resonator to amplify the ultrasonic vibrations in ultrasonic probe 10. Gaussian-type resonators are described generally in uchinich et al . , U.S. Patent 4,922,902, titled METHOD FOR REMOVING CELLULAR MATERIAL WITH ENDOSCOPIC ULTRASONIC ASPIRATOR, incorporated by reference herein. As described in the Wuchinich 4,992,902 patent, by varying the cross- sectional area of an ultrasonic probe according to a

Gaussian function, the velocity of the ultrasonic vibrations can be rapidly increased while maintaining a safe operating stress in the probe material .

A constant diameter inner surface 42 of wall 8 defines a constant wall thickness region 26 of wall 8 extending proximally from transition plane 24 to proximal end 14. Distal region 12 and mid region 16 have a constant outer diameter, for example about 0.2 inch, producing a smooth, continuous outer profile.

A cap 28 abuts distal region 12 of ultrasonic probe 10 to close off distal end 7 of lumen 18. Cap 28 is secured to head portion 12 by, for example, welding, brazing, gluing, or press fitting, or with a machine thread. A pair of openings 32 extend through wall 8 in distal region 12 and are circumferentially spaced apart by 180°. Openings 32 are in fluid communication with lumen 18. Openings 32 and lumen 18 provide a channel through which suction is applied to remove treated tissue from the surgical site by, for example, an aspirator connected to a proximal opening 30 of lumen 18.

Probe 10 is preferably made from titanium. Probe 10 can also be made from other materials, for example aluminum or stainless steel. For a 27 KHz ultrasonic probe, the length of tapered wall portion 20 from transition plane 24 to distal end 7 is about 1.5 inches, with the remainder of probe 10 having a length of about 12 inches. The thickness of wall 8 is about 0.05 inch at transition plane 24 and about 0.025 inch at distal end 7. Thus, the inner diameter of tapered wall portion 20 increases from about 0.100 inch at transition plane 24 to about 0.15 inch at distal end 7. The dimensions and shape of probe 10 can be varied according to the application requirements and needs.

In operation, ultrasonic vibrations generated in handpiece 50 are delivered to proximal end 14 of probe 10. The velocity of the ultrasonic vibrations is amplified at step down 40. The amplified vibrations are transmitted through mid region 16 to distal region 12 where the velocity of the ultrasonic vibrations is again amplified. Tissue in the vicinity of distal end 7 is treated by the ultrasonic vibrations and treated tissue is aspirated through openings 32 and lumen 18. Amplification of the ultrasonic vibration is provided at distal region 12 without requiring a change in the outer profile of the probe. Since the outer surface of distal region 12 is smooth, the possibility of snagging and/or cutting soft tissue is minimized during the ultrasonic liposuction procedure.

Other embodiments are within the scope of the following claims.

For example, referring to FIGS. 3A-3C, a lumen 118 of probe 110 is defined by a wall 108 having step-down sections 120, 122 rather than a taper such that the diameter of the lumen increases as the lumen extends distally. Step down 120 is located at a length, L_1# at or near a distal most node of vibration, e.g., about 1.8 inches, from distal end 124 of probe 110. The thickness of wall 108 decreases in the distal direction at step down 120 such that the inner diameter of lumen 118 increases, e.g., from about 0.125 inch (d to about 0.15 inch (d₂) . Step down 122 is located at a length, L₂, at or near a node of vibration, e.g., about 3.5 inches, from step down 120. The thickness of wall 108 decreases in the distal direction at step down 122 such that the inner diameter of lumen 118 increases, e.g., from about 0.1 inch (d₃) to about 0.125 inch (d- . As the ultrasonic energy is transmitted through probe 110, the change in diameter at step down 120 and at step down 122 amplifies the velocity of the acoustic wave through probe 110. Alternatively, probe 110 can have a single step-down section.

Referring to FIG. 3D, it is also contemplated that probe 110 include another step down 130 located distally of step 120 for providing additional amplification of the velocity of the acoustic wave. Step down 130 is located at a length, L₃, about 1.25 inches, from distal end 124 of probe 110. The thickness of wall 108 decreases in the distal direction at step down 130 such that the inner diameter of lumen 118 increases, e.g., from about 0.15 inch (d₂) to about 0.175 inch (d₄) . Probe 10 can be constructed without a cap 28. Probe 10 can include an enlarged distal head such as described in Podany et al . , ULTRASONIC ASSISTED LIPOSUCTION SYSTEM, supra .

Probe 10 can be used in conjunction with a sheath to provide infiltration/irrigation capabilities to the ultrasonic liposuction procedure. In such a combination, the sheath is disposed about probe 10, thereby defining a channel between probe 10 and the sheath through which the infiltration/irrigation fluid flows.

Other types of resonators, for example, conical, exponential, catenoidal, and Fourier resonators, can be employed in ultrasonic probe 10.

One, two or more openings can be located in distal region 12. Multiple openings can be equally or unequally spaced about the distal region. The ultrasonic probe may be configured to treat tissue other than adipose tissue.

Claims

What is claimed is:

1. A probe for ultrasonic tissue treatment, comprising: a body having a wall defining a lumen, a thickness of the wall decreasing in a distal direction such that the lumen increases in cross-section in the distal direction.

2. The probe of claim 1 wherein the wall tapers to a smaller thickness in the distal direction.

3. The probe of claim 1 wherein the wall steps down to a smaller thickness in the distal direction.

4. The probe of claim 3 wherein the wall steps down in the vicinity of a node.

5. The probe of claim 3 wherein the wall steps down in the vicinity of a plurality of nodes.

6. The probe of claim 3 wherein the wall steps down distally of a distal most node.

7. The probe of claim 1 wherein the probe is cylindrical and an outer diameter of the probe remains constant while the thickness of the wall decreases.

8. The probe of claim 1 wherein a length of the body over which the wall thickness decreases is a minority portion of an overall length of the body.

9. The probe of claim 8 wherein a majority portion of the overall length of the body has a constant wall thickness.

10. The probe of claim 1 further defining an opening at a distal tip of the probe, the opening being in fluid communication with the lumen.

11. The probe of claim 10 further including a cap mounted on the distal tip for covering the opening at the distal tip.

12. The probe of claim 1 further defining an opening extending through the wall .

13. The probe of claim 12 further defining a plurality of openings extending through the wall.

14. The probe of claim 13 wherein the plurality of openings are equally spaced about the body.

15. The probe of claim 13 wherein the body is cylindrical and the plurality of openings are equally spaced about a circumference of the body.

16. The probe of claim 12 wherein the opening extends radially from a longitudinal extent of the lumen.

17. The probe of claim 1, wherein said probe is configured to treat adipose tissue.

18. A method of amplifying the amplitude of ultrasonic vibrations, comprising: applying ultrasonic vibrations to a proximal end of an ultrasonic probe, and amplifying the ultrasonic vibrations by decreasing a thickness of a wall of the ultrasonic probe in a distal direction such that a lumen defined by the wall increases in cross-section in the distal direction.