HK1231352B - Ultrasonic debrider probe - Google Patents

Description

Ultrasonic debridement probe

Technical Field

The present invention relates to the field of ultrasonic surgical instruments, and in particular to a high-efficiency medical probe for wound debridement.

Background Art

In the past 30 years, several ultrasonic tools have been invented that can be used to remove or cut tissue during surgery. Such devices are disclosed by Wuchinich et al. in U.S. Patent No. 4,223,676 and Idemoto et al. in U.S. Patent No. 5,188,102.

In practice, these surgical instruments include a blunt-tipped hollow probe that vibrates at a frequency between 20 kc and 100 kc with an amplitude of up to 300 microns or more. Such instruments remove tissue by generating cavitation bubbles that implode and destroy cells, tissue compression and relaxation stress (sometimes referred to as a jackhammer effect), or by other forces such as microstreaming of tissue matrix bubbles. This effect causes the tissue to liquefy and separate. It then becomes emulsified with an irrigant solution. The resulting emulsion is then drawn from the site. By applying energy around and below the target tissue, it can be separated from surrounding structures, allowing for the removal of a large portion of the tissue. The surgeon can then use ordinary tools such as medical forceps to lift the tissue.

The probe or tube is excited by a piezoelectric or magnetostrictive transducer, which converts an alternating electrical signal at a frequency that translates into longitudinal or transverse vibration. When the probe is attached to the transducer, the two become a single element with series and parallel resonances. Designers will attempt to adjust the mechanical and electrical properties of these elements to provide the appropriate operating frequency. Typically, the element will have a straight long axis and the tip truncated in a plane perpendicular to the long axis, as shown in Figure 1. This is done for simplicity and economy. This embodiment is practical and beneficial in almost all applications, whether medical or industrial. However, in applications such as debridement of burns, wounds, diabetic ulcers, or ulcers caused by radiation therapy, blunt straight probes have proven less effective in removing the hard eschar deposits that occur during wound healing. This eschar deposit must be removed to expose healthy tissue and close the wound to provide complete healing with minimal scar tissue formation. Furthermore, due to the small diameter of the cylindrical tip, a small annular region limits energy transmission into the wound. This prolongs the procedure and causes operator fatigue and patient discomfort.

U.S. Patent No. 7,931,611 discloses an ultrasonic wound debridement probe having a central bore coincident with a longitudinal axis. The proximal end of the bore communicates with a bore in the ultrasonic handpiece using methods well known in the art, such as a male/female thread combination. The probe is shaped to provide an operating resonant frequency within the designed range of the electronic oscillator and a vibration amplitude at the distal end face that is desired for tissue ablation. Such amplitudes have generally been demonstrated to be in the range of 30 to 300 microns. As disclosed in U.S. Patent No. 7,931,611, the probe head or tip may include a generally symmetrical tip or a tip with significant asymmetry. Each tip may have properties that enhance its effect on altering tissue pathology. The probe head may be further modified to increase fluid flow to the probe/tissue interface, thereby reducing the bulk of tissue temperature rise and preventing blockage of fluid pathways. The probe tip may also be modified to create an energy director that applies energy from both ends of the probe, rather than solely at the distal end face of the probe. Such energy directors, when in contact with skin or tissue, increase the amount of tissue treated per unit time, thereby reducing the operating time of the procedure. In one embodiment of U.S. Patent No. 7,931,611, an ultrasonic medical probe comprises an elongated shaft integrally formed with a tip portion, the tip portion having a terminal end face oriented at least partially transverse to the longitudinal axis of the shaft. The shaft is provided with an internal longitudinal channel or bore extending to the end face. The end face is formed by a recess that communicates with the channel or bore at one end of the probe, whereby liquid is directed through an extended surface of the end face relative to the channel or bore. The tip portion may be enlarged in a transverse direction relative to the shaft. In that case, the end face has an elongated shape, and the recess is extended to form a groove at one end face of the tip portion. This groove may extend parallel to or extend along the length dimension of the end face.

A problem that sometimes occurs with conventional wound debriders and other ultrasonic surgical tools is that the irrigation channels or apertures, which may be intermittently connected to the suction source, sometimes become clogged with tissue, thereby reducing the effectiveness of the irrigation and/or suction.

Summary of the Invention

The present invention is directed to an improved ultrasonic surgical instrument for wound debridement, particularly in the form of a probe that can be used in conjunction with an ultrasonic surgical aspirator to debride wounds. More specifically, the present invention contemplates an ultrasonic surgical instrument having improved irrigation or aspiration capabilities and/or improved tissue removal capabilities.

A probe used as an ultrasonic vibration tool according to the present invention has a central bore that is aligned with the longitudinal axis of the probe shaft. The proximal end of the bore is connected to a hole in an ultrasonic handpiece using methods well known in the art, such as a male/female thread combination. The probe is shaped to provide an operating resonant frequency within the design range of the electronic oscillator and a vibration amplitude at the distal end that is desired for suitable tissue ablation. Such amplitudes are generally indicated to be in the range of 30 to 300 microns. Again, the techniques required to calculate this shape are well known in the prior art and are beyond the scope of the present disclosure.

An ultrasonic surgical instrument according to the present invention includes (a) a shaft having a lumen or channel and a longitudinal axis and (b) a probe head disposed at a distal end of the shaft, the probe head having a distal end surface. The probe head has at least one operative surface that engages with organic tissue to apply ultrasonic vibration energy to the tissue. The end surface is oriented at least partially transverse to the axis and can be oriented perpendicular to the axis. The lumen or channel has a first opening or port at the end surface, and at least one second opening or port is provided on a side surface of one of the shaft or the probe head at a location spaced apart from the end surface.

Also according to the present invention, an ultrasonic surgical instrument includes a shaft having a longitudinal axis and a probe head disposed at a distal end of the shaft, the probe head having a distal end surface oriented at least partially transverse to the axis, the probe head having a plurality of teeth extending laterally from the end surface.

Preferably, the probe head is wider than the shaft, extends to opposite sides of the axis, and is formed by a pair of opposing side surfaces extending from one end of the shaft to the end surface. The instrument axis is disposed in a plane that bisects the end surface when the side surfaces of the probe head are spaced from the plane. The teeth extend from the plane generally orthogonal to the plane.

According to another feature of the invention, the teeth are arranged in two rows, each row being along an opposite edge of the end face, the teeth of one row extending in a direction opposite to the teeth of the other row.

Preferably, the end face is offset or tilted relative to the axis so that the teeth in any row are arranged at different distances from the axis. The teeth in any row are thus arranged in a linear array that is offset or tilted relative to any plane perpendicular to the axis.

According to another feature of the invention, the teeth have operative surfaces at free ends spaced apart from (and oriented parallel to) the plane of the bobbin, the operative surfaces being defined on a proximal side by respective sharp edges, wherein the end face of the probe head is tilted or inclined relative to the axis of the bobbin so that the teeth are arranged in respective linear arrays each tilted or inclined relative to a plane perpendicular to the axis, the sharp edges of the teeth in any row being likewise linearly arranged.

During operation of the instrument, the operating surface or teeth on another row are placed in contact with the tissue surface at the surgical site. During subsequent ultrasonic vibrations of the instrument, the sharp edges of the teeth are tilted and repeatedly drawn across the tissue surface, shaving layers of tissue from the surgical site. The tilting of the teeth relative to the direction of ultrasonic reciprocating motion (parallel to the axis of the instrument) causes the end face to oscillate, which moves the shaved tissue fragments toward the gaps between the teeth, where they are subjected to suction or air aspiration at the end face of the probe head through a channel port or opening. This opening is preferably located centrally between the rows of teeth.

The sharp proximal edge of the teeth is preferably a straight edge.It should be noted that at one end opposite the handpiece and the probe shaft, the teeth may alternatively or additionally be formed with a sharp cutting edge.

According to a more specific feature of the present invention, the probe head is further formed using a plurality of concave ramp surfaces, the number of concave ramp surfaces being equal to the number of teeth, and each extending from an opposing side surface of the probe head to a sharp edge on a respective proximal end of a tooth. Each tooth can be formed by a pair of planar side surfaces arranged parallel to each other and transverse to the sharp tooth edge. These side tooth surfaces extend in planes oriented at a generally acute angle relative to an axial plane that bisects the end face of the probe head.

The present invention contemplates a surgical method using an ultrasonic instrument having a tip with a plurality of spaced-apart teeth along a distal end surface of the tip. The method generally includes manipulating the instrument to press the teeth against tissue at a surgical site. While maintaining the teeth in contact with the tissue at the surgical site, vibrational energy is applied to the instrument and the instrument is dragged across the surgical site, thereby shaving tissue debris from the surgical site in a raking action.

The method typically includes delivering at least a portion of an irrigation solution to tissue at the surgical site through a channel in the instrument while applying ultrasonic vibration energy to the instrument and dragging the instrument across the surgical site. Separated tissue fragments are then aspirated from the surgical site through the channel. While the instrument is being dragged across the surgical site, the shaved tissue fragments are moved toward the gaps between the teeth, where they are subjected to suction or air aspiration through a port or opening in a distal end face of the instrument.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partial perspective view of an ultrasonic surgical instrument, probe, or tool according to the present invention.

2 is a side view of the probe head of the instrument or tool of FIG. 1 .

3 is a front or end elevation view of the instrument or tool of FIGS. 1 and 2 .

FIG. 4 is a longitudinal sectional view taken along line IV-IV in FIG. 3 .

DETAILED DESCRIPTION

Ultrasonic surgical instrument 10, particularly suitable for wound debridement, includes a shaft or handle 12 having a longitudinal axis 14 and a lumen or passageway 16 coaxial with the longitudinal axis ( FIG. 4 ). Instrument 10 further includes a probe head 18 disposed at the distal end of shaft 12, the probe head having a distal end face 20. Probe head 18 has a plurality of operative surfaces 22 capable of engaging with organic tissue for applying ultrasonic vibration energy to the tissue. End face 20 is oriented at least partially transverse to longitudinal axis 14. Lumen or passageway 16 extends through probe head 18 and has a first opening or port 24 at probe head end face 20 ( FIG. 4 ). Lumen or passageway 16 has at least one second opening or port 26, preferably located on an outer side 28 of shaft 12, spaced apart from probe head 18 and, in particular, end face 20 thereof. Openings or ports 26 and 26 serve as drains when cleaning is performed through lumen or passageway 16 and as water inlets when aspiration or suction is performed.

As shown in Figures 1 and 4, probe head 18 is wider than axis 12 and is therefore laterally enlarged relative to axis 12. Probe head 18 extends to opposite sides of axis 14 and is bisected by a longitudinal plane P1 (Figure 3) containing axis 14. Probe head 18 has a plurality of teeth 30 and 32 extending laterally from end face 20. Teeth 30 and 32 are arranged in respective rows or linear arrays 34 and 36, extending parallel to each other and parallel to plane P1. Tooth arrays 34 and 36 are spaced apart from opposite sides of plane P1. The teeth extend generally orthogonally thereto. Probe head 18 is mirror-symmetrical about plane P1 and may additionally be mirror-symmetrical about a second longitudinal plane P2 (Figure 3) containing axis 14 and oriented orthogonal or perpendicular to plane P1.

The probe head 18 is defined in part by a pair of opposing major side surfaces 38 and 40 that extend from one end of the shaft 12 to the end face 20 and, in particular, to the teeth 30 and 32. More specifically, the major side surfaces 38 and 40 flare outwardly from the end of the shaft 12 to the end face 20 and, at their distal ends, extend to the teeth 30 and 32 and to a plurality of edges 42 and 44 of the end face 20 that are disposed between adjacent teeth 30 and 32 and at their bases or roots.

As shown in FIG2 , end face 20 is disposed in a plane P3 that is offset or tilted at an angle a1 relative to a transverse plane P4 that is perpendicular to axis 14. The different teeth 30 of row or array 34 and the teeth 32 of row or array 36 are disposed at different distances d1, d2, ..., dn from axis 12. The rows or arrays of teeth 34 and 36 are offset or tilted relative to any plane perpendicular to axis 14, such as plane P4.

It should be noted that angle a1 can be zero, in which case the teeth 30 are all disposed the same distance from the end of the shaft 12. In general, angle a1 can take any value between 0 degrees and approximately 30 degrees.

Operating surfaces 22 and 22' are positioned at the free ends of teeth 30 and 32 and are spaced laterally from axis plane P1. Operating surfaces 22 and 22' are illustratively oriented parallel to plane P1. Operating surfaces 22 and 22' are defined proximally by respective sharp edges 46 and 48. Opposing major side surfaces 38 and 40 of probe head 18 are connected and defined at their distal ends by edges 46 and 48. Because end surface 20 (e.g., plane P3) is tilted or inclined relative to axis 14, edges 46 and 48 of teeth 30 and 32 are also aligned.

During operation of the instrument, when teeth 30 or 32, more specifically, when operative surface 22 or 22', are placed in contact with a tissue surface at a surgical site, an irrigation fluid, such as saline solution, is delivered through channel 16 to the tissue at the surgical site and to openings or ports 24 and 26, as indicated by arrows 162, 164, and 166. During subsequent ultrasonic vibration of instrument 10, sharp edges 46 or 48 of teeth 30 or 32 are tilted and repeatedly drawn across the tissue surface, shaving layers of tissue from the surgical site. The tilting of these teeth relative to the direction of ultrasonic reciprocating motion (parallel to the axis of the instrument) creates end face abutment, forcing shaved tissue fragments toward gaps (not separately designated) defined between the teeth by inter-tooth edges 42 or 44, where they are subjected to suction forces or aspiration through port or opening 24 in probe end face 20. Due to the symmetry of probe head 18, and particularly end face 20, opening 24 is positioned at the geometric center of axis 14, between rows 34 and 36 of teeth 20 and 32.

The cutting edges 46 and 48 of the teeth 30 and 32 are preferably, but not necessarily, straight edges. The teeth 30 and 32 may alternatively or additionally be formed with sharp cutting edges at their distal sides 50 and 52, opposite the handpiece (not shown) and the probe shaft 12.

Probe head 18 includes a plurality of concavely angled surfaces 54 and 56, each of which partially defines a respective tooth 30 or 32 and each of which extends from one of the opposing sides 38 and 40 of probe head 18 to a sharp edge 46 or 48 on the proximal side of the respective tooth 30 or 32. Each tooth 30 and 32 may be formed with a respective pair of planar side surfaces 58 and 60, all disposed parallel to each other and transverse to sharp tooth edges 46 and 48. Side tooth surfaces 58 and 60 extend in plane P5, which is oriented to subtend a generally acute angle a2 relative to axial plane P2 (which bisects end face 20).

The probe head 18 further includes a plurality of extension surfaces 62 that alternate or interleave with the concave tooth-defining surfaces 54 and 56 and abut or terminate at the respective inter-tooth edges 42 and 44 of the end face 20 .

Providing an auxiliary irrigation and aspiration port 26, disposed in the shaft 12 or possibly on the outer surfaces 38 and/or 40, enhances the ability of the instrument 10 to provide continued aspiration of a surgical site if the primary aspiration port 24 becomes clogged or occluded by severed tissue.

It should be noted that an opening or port 64 of the passageway 16 may be located on the outer surface of the probe head 18 instead of or in addition to the port 26 of the shaft 12 .

Claims (17)

1. An ultrasonic surgical instrument, comprising: A shaft having an internal cavity or channel and a longitudinal axis; and A probe head disposed at the end of the shaft, the probe head having an end face, the probe head having at least one operating surface capable of engaging with organic tissue to apply ultrasonic vibration energy to the tissue, the end face being oriented at least partially transverse to the axis, the lumen or channel having a first opening or port on the end face, the lumen or channel having at least one second opening or port at a spaced apart from the end face on a side surface of one of the shaft and the probe head, the probe head having a plurality of teeth, each tooth on the probe head being positioned along the edge of the end face and extending partially transversely from the end face. 2. The device of claim 1, wherein the teeth are configured as two linear rows or arrays, each linear row or array along opposite edges of the end face, and a tooth of one of the two linear rows or arrays extends in the opposite direction of a tooth of the other of the two linear rows or arrays. 3. The device according to claim 2, wherein the end face is biased or inclined relative to the axis, such that the teeth of either of the two linear rows or arrays are arranged at different distances from the axis. 4. The device according to claim 3, wherein the tooth has an operating surface that is laterally spaced from the axis at a free end, the operating surfaces being defined on a proximal side by their respective sharp edges. 5. The device according to claim 4, wherein the sharp edge is a straight edge. 6. The device of claim 5, wherein the probe head is wider than the shaft and extends to the opposite side of the shaft, the probe head is formed by a pair of opposite side surfaces extending from the end of the shaft to the end face, the probe head is further formed by a plurality of concave bevel surfaces, the number of the concave bevel surfaces being equal to the number of the teeth, and each concave bevel surface extending from one of the opposite side surfaces to the respective straight edge of the tooth. 7. The device of claim 4, wherein each of the teeth has a pair of planar side surfaces configured to be parallel to each other, the side surfaces extending in a plane oriented at a conventional acute angle relative to the axis. 8. The device of claim 5, wherein the probe head is wider than the shaft and extends to the opposite side of the shaft, the probe head is formed by a pair of opposite side surfaces extending from the end of the shaft to the end face, the probe head is further formed by a plurality of concave bevel surfaces, the number of the concave bevel surfaces being equal to the number of the teeth, and each concave bevel surface extending from one of the opposite side surfaces to the respective straight edge of the tooth. 9. An ultrasonic surgical instrument, comprising: a shaft having a longitudinal axis; and a probe head disposed at an end of the shaft, the probe head having an end face oriented at least partially transverse to the axis, the probe head having a plurality of teeth extending in a linear array along an edge of the end face and extending at least partially transversely from the end face, all teeth on the probe head being positioned along an edge of the end face. 10. The device of claim 9, wherein the probe head is wider than the shaft and extends to the opposite side of the shaft, the probe head is formed by a pair of opposing side surfaces extending from the end of the shaft to the end face, the shaft is disposed on a plane bisecting the end face, the side surfaces are spaced apart from the plane, and the teeth extend orthogonally from the plane. 11. The device of claim 10, wherein the teeth are configured as two linear rows or arrays, each linear row or array along opposite edges of the end face, and a tooth of one of the two linear rows or arrays extends in the opposite direction to a tooth of the other of the two linear rows or arrays. 12. The device of claim 11, wherein the end face is biased or inclined relative to the axis, such that the teeth of either of the two linear rows or arrays are arranged at different distances from the axis. 13. The device of claim 12, wherein the tooth has an operating surface that is laterally spaced from the plane at a free end, the operating surfaces being defined on a proximal side by their respective sharp edges. 14. The device according to claim 13, wherein the sharp edge is a straight edge. 15. The device of claim 14, wherein the probe head is further formed by a plurality of concave bevel surfaces, the number of which is equal to the number of the teeth, and each concave bevel surface extends from one of the opposite side surfaces to a respective straight edge of the tooth. 16. The device of claim 10, wherein each of the teeth has a pair of planar side surfaces configured to be parallel to each other, the side surfaces extending in a plane oriented at a conventional acute angle relative to the plane. 17. The device of claim 9, wherein the shaft has an inner cavity or channel, and the teeth have respective operating surfaces capable of engaging with organic tissue to apply ultrasonic vibration energy to the tissue, the inner cavity or channel having a second opening or port at a position spaced apart from the end face on a side surface of one of the shaft or the probe head.