Ultrasonic surgical instrument having a probe angled relative to a handpiece - Patents.com

Abstract

The ultrasonic surgical instrument includes a handpiece casing and an electromechanical transducer assembly disposed within the handpiece casing, where the transducer assembly includes a forward driver, the transducer assembly having a longitudinal axis. A probe is operatively connected to the forward driver at an acute angle relative to the longitudinal axis of the transducer assembly. A sheath surrounds the probe and is connected to the handpiece casing at a proximal end. The sheath is attached to the casing by a twist-type quick release connection. A diaphragm seal disposed within the proximal end of the sheath prevents liquid irrigant in a cylindrical space between the sheath and the probe from entering a location proximal to a port that supplies irrigant to the space. The forward driver is geometrically configured to allow for an angled connection between the probe and the handpiece near a nodal plane.

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The present invention relates to ultrasonic tools or instruments for use in medical surgery. [Background technology]

[0002] Ultrasonic tools are increasingly being used in surgery. Ultrasonic ablation tools are well-known for their accuracy, reliability, and ease of use. Ultrasonic bone cutting blades can be designed to facilitate cutting of bone without damaging adjacent soft tissue. See U.S. Pat. No. 8,343,178. Ultrasonic debriders remove necrotic or other damaged tissue without damaging underlying healthy tissue. Ultrasonic instruments such as debriders can have integrated tissue treatment modalities, such as high energy current transmission for cauterization (see U.S. Pat. No. 6,648,839), low energy electrical energy transmission for pain control (U.S. Pat. App. Pub. No. 2008 / 0146921), or stimulation for tissue repair (U.S. Pat. No. 8,025,672).

[0003] Ultrasonic instruments can include probes with curved shafts to facilitate access to problem areas. In some surgical procedures, it is advantageous to angle the surgical head or end effector portion of the probe to one side of the shaft to further facilitate access to the desired surgical site. See U.S. Pat. No. 10,398,463. Alternatively, the probe can be generally straight and mounted at an angle to the handpiece. See U.S. Pat. Nos. 5,312,329 and 5,484,398.

[0004] In developing a new set of ultrasonic instruments in which the handpiece could be utilized with a variety of probes that may have different end effectors and different surgical capabilities, the applicant encountered some unexpected problems. In the case of a rigid sheath that defines an annular fluid flow path between the sheath and the probe, the user could sometimes feel a burning or tingling sensation in one hand when placing the hand over the sheath just distal to the handpiece. It was soon discovered that whether or not this sensation was felt depended on whether or not the hand was compressing the sheath.

[0005] Another issue was designing the handpiece and proximal end of the probe so that the probe could be easily removed and another tool attached for easy replacement in the operating room. For example, during spinal surgery, it may be desired to change from a bone cutting instrument to an abrasive instrument or to a debridement instrument.

[0006] Other considerations include optimizing the efficiency of ultrasonic energy transfer from the transducer array in the handpiece to the probe, which is not so simple given the angular relationship of the two instrument parts. Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the present invention to provide an improved ultrasonic tool or instrument that is effective for use in minimally invasive surgery.

[0008] It is another object of the present invention to provide such an improved ultrasonic tool or instrument which has a probe which extends at an angle relative to the handpiece.

[0009] It is a more specific object of the present invention to provide such a tool or instrument having a sheath disposed about the probe with fluid flow between the probe and the sheath, whereby the risk of pain in holding the sheath during surgery is reduced or eliminated.

[0010] It is another object of the present invention to provide such a tool or instrument in which the probe is easily attached and detached from the handpiece.

[0011] It is a further object of the present invention to provide such a tool or instrument that is configured to efficiently transfer ultrasonic mechanical vibration energy from the handpiece to the probe.

[0012] These and other objects of the present invention will be apparent from the description and drawings herein. While all of the objects of the present invention may be achieved by one or more embodiments of the present invention, there is not necessarily a single embodiment that achieves all of the objects of the present invention. [Means for solving the problem]

[0013] Thus, an ultrasonic surgical instrument according to the present invention includes a handpiece casing and an electromechanical transducer assembly disposed within the handpiece casing, where the transducer assembly includes a forward driver, the transducer assembly having a longitudinal axis. The instrument further includes a probe operatively connected to the forward driver at an acute angle relative to the longitudinal axis of the transducer assembly (and typically the handpiece casing). The probe has a distal end provided with an end effector, such as a blade or debridement surface. A sheath surrounds the probe, the sheath being connected to the handpiece casing at a proximal end, while the end effector extends distally beyond the distal tip of the sheath. The sheath is provided with an annular seal member at its proximal end that engages against a distal face of the handpiece casing. At least two first occlusion members and a similar number of second occlusion members are provided at the proximal end of the sheath and at the distal end of the handpiece casing. The first occlusion members are disposed on either the distal face of the handpiece casing or the proximal end of the sheath, while the second occlusion members are disposed on either the proximal end of the sheath or on the distal face of the handpiece casing. Each of the first occlusion members is in the form of a radially extending protrusion (extending inwardly from the outer member or extending outwardly from the inner member) while each of the second occlusion members is in the form of an annular open channel or groove defined by a cam surface and having a tapered end.

[0014] Preferably, the annular sealing member is made from a resiliently compressible material having a suitable surface coefficient of friction. The first and second occlusion members are configured to frictionally lock the sheath to the handpiece casing by compressing the annular sealing member. Locking and unlocking of the sheath to the handpiece casing is achieved by counter-twisting the sheath relative to the handpiece. Thus, the cam mechanism allows the sheath to be quickly coupled to and similarly quickly uncoupled from the handpiece.

[0015] Thus, the handpiece casing is preferably secured to the sheath by a single locking mechanism, the single locking mechanism including the annular sealing member, the first occlusion member and the second occlusion member.

[0016] The protrusion may be in the form of a special annular rib extending in a plane transverse to the axis of the sheath. The cam surface is disposed along the distal side of the annular open channel and faces proximally towards the handpiece casing.

[0017] The ultrasonic surgical instrument according to the present invention includes a handpiece casing and an electromechanical transducer assembly disposed within the handpiece casing, the transducer assembly including a forward driver, the transducer assembly having a longitudinal axis. A probe is operatively connected to the forward driver at an acute angle to the longitudinal axis, the probe having a distal end with an end effector. A sheath surrounds the probe, the sheath is connected to the handpiece casing at a proximal end, the end effector extending distally beyond the distal tip of the sheath. The sheath includes a port adjacent the proximal end connectable to a source of pressurized liquid coolant for flowing the pressurized liquid coolant into a tubular space between the probe and an inner surface of the sheath. A diaphragm seal is disposed within the proximal end of the sheath proximal to the port, the diaphragm seal having an annular outer surface in fluid-tight contact with the inner surface of the sheath. The diaphragm is provided with an inwardly extending annular flange at its distal end which circumferentially engages the outer surface of the probe in a fluid tight seal, the inwardly extending annular flange preferably engaging the outer surface of the probe at a node of ultrasonic transmission.

[0018] The entire diaphragm, except for the inwardly extending annular flange, is preferably spaced from the probe, and the diaphragm seal, as described above, eliminates any painful or uncomfortable sensations that may sometimes be felt when a user grasps the proximal end portion of the sheath.

[0019] In accordance with another feature of the invention, the diaphragm is provided at its proximal end with an outwardly extending annular flange which is clamped between the proximal end face of the sheath and the distal end face of the handpiece casing.

[0020] In accordance with another feature of the invention, the sheath has a main body at a proximal end made from a rigid material, the sheath further including a distal end portion made from a silicone polymer.

[0021] The ultrasonic surgical instrument according to the present invention includes a handpiece casing and an electromechanical transducer assembly disposed within the handpiece casing, the transducer assembly including a forward driver, the instrument further including a probe operatively connected to the forward driver at an acute angle relative to a longitudinal axis, the probe having a distal end with an end effector or working head. The forward driver has an outwardly projecting annular flange and is formed with a first outer cylindrical surface at its distal end that is coaxial with the longitudinal axis of the transducer assembly. The forward driver has a second outer cylindrical surface at its distal end opposite the first outer cylindrical surface, the second outer cylindrical surface being coaxial with the longitudinal axis of the probe.

[0022] According to a further feature of the invention, the front driver has two parallel planar outer surfaces extending parallel to the longitudinal axis of the transducer assembly, each of the two parallel planar outer surfaces being articulated to a first outer cylindrical surface and a second outer cylindrical surface.

[0023] The handpiece casing preferably defines a first inner cylindrical surface at its distal end that is coaxial with the longitudinal axis of the transducer assembly, and further defines a second inner cylindrical surface that is coaxial with the longitudinal axis of the probe.

[0024] The ultrasonic surgical instrument according to the present invention includes a handpiece casing and an electromechanical transducer assembly disposed within the handpiece casing, the transducer assembly including a forward driver having an internally threaded receptacle at a distal end. A tubular member extends through the transducer assembly to a proximal end of the internally threaded receptacle. A probe having a longitudinal bore is operatively connected to the forward driver at an acute angle relative to a longitudinal axis of the transducer assembly, the probe having a distal end with an end effector. The internally threaded receptacle is adapted to receive an externally threaded connector at the proximal end of the probe and has a proximal end face disposed at an acute angle relative to the longitudinal axis of the transducer assembly. A sheath surrounds the probe, the sheath is connected to the handpiece casing at a proximal end, the end effector extending distally beyond the distal tip of the sheath. The tubular member has a lumen having a uniform cross-section including a distal end opening of the lumen. The probe bore has a proximal end opening of a cross-section smaller than the cross-section of the tubular member. The probe bore is aligned with the distal end opening of the tubular member. Together, the tubular member and the bore define a continuous lumen that does not have a distally facing shoulder at the junction of the tubular member and the bore.

[0025] A cradle for use in manually mounting an ultrasonic probe to a handpiece at an acute angle to the axis of the handpiece, according to the present invention, includes a frame and a support on the frame defining an acute angle with a bottom surface of the frame. The frame has a stop at one end thereof that is engageable with a front end of the handpiece. The stop has an opening that allows a user access to a front driver of a transducer assembly housed within the handpiece. Two wings extend in opposite directions from the frame at the bottom surface of the frame, the two wings being adapted to contact a flat surface on which the frame is placed. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a side view of an ultrasonic surgical instrument according to the present invention. [Diagram 2] FIG. 2 is a longitudinal section taken parallel to the drawing plane of FIG. 1; [Diagram 3] 3 is a longitudinal cross-sectional view taken along the same plane as the view of FIG. 2, showing the probe and transducer array disposed within the handpiece casing shown in FIGS. 1 and 2; FIG. [Figure 4] 4 is a perspective view including front, side and top views of the operating structure shown in FIG. 3, namely, the probe, the transducer array and the proximal end cap assembly of the handpiece casing. [Diagram 5] 4 is an enlarged partial longitudinal sectional view of a portion V in FIG. 3, showing the coupling of a probe and a transducer. [Figure 6] FIG. 13 is a longitudinal cross-sectional view of the front driver of the transducer array. [Figure 7] FIG. 3 is a side view of the handpiece casing in FIGS. 1 and 2. [Figure 8] FIG. 8 is a front view of the handpiece casing in FIGS. 1, 2, and 7. [Figure 9]FIG. 9 is a perspective view including a plan view, a side view, and a front view of the handpiece casing in FIGS. 1, 2, 7, and 8. [Figure 10] 3 is an enlarged partial longitudinal cross-sectional view of portion X in FIG. 2, showing the diaphragm seal and the connection between the sheath and the casing. [Figure 11] FIG. 3 is a side view of a cradle holding the ultrasonic instrument of FIGS. 1 and 2 in an orientation for manual attachment of a probe (eg, FIGS. 3, 4) to a handpiece casing. [Figure 12] 11 is a perspective view including plan, front and side views of the ultrasonic instrument of FIGS. 1 and 2 with partial exploded views, showing the handpiece supported in the cradle of FIG. 11 and the probe positioned for installation. [Figure 13] 3 is a perspective view including top, front and side views of the assembled ultrasonic instrument of FIGS. 1 and 2 after the probe has been attached to the handpiece casing. FIG. [Figure 14] 14 is a perspective view including top, front and side views of the cradle and instrument in FIG. 13, further showing a wrench for tightening the probe to the handpiece or for loosening the probe to remove it from the handpiece. [Figure 15] FIG. 2 is a cross-sectional view taken along line XIII-XIII in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] As shown in Figures 1 and 2, the ultrasonic surgical instrument includes a handpiece casing 10 and an electromechanical transducer assembly 12 disposed within the casing, where the transducer assembly includes a forward driver 14 and has a longitudinal axis 16 (Figures 3 and 5). The instrument further includes a probe 18, typically made of a metal alloy, operatively connected to the forward driver 14 at an acute angle, e.g., 20°, to the longitudinal axis 16 of the transducer assembly 12. The transducer assembly 12 is preferably symmetrically disposed within the casing 10 such that the axis 16 also serves as the longitudinal axis of symmetry of the casing. The probe 18 has a distal end (not separately designated) provided with an end effector 20, such as a bone cutting blade (not shown) or a debridement head (as shown). A sheath 22 surrounds the probe 18, except for an end effector or working head 20, and is connected at its proximal end to the handpiece casing 10. The end effector or working head 20 extends distally beyond a distal tip 24 of the sheath 22.

[0028] The transducer assembly 12 is of a construction well known in the art and basically includes a number of annular piezoelectric disks 26 and a thinner annular metallic electrode 28 arranged in a linear array about the longitudinal axis 16 and interposed between a distal front driver 14 and a proximal rear driver 30, as shown in Figures 2 and 3. The electrode 28 is connected to an ultrasonic electrical waveform generator (not shown) which causes the piezoelectric disks to alternately expand and contract parallel to the transducer axis 16, thereby creating ultrasonic standing waves in the probe 18 which in turn reciprocate the end effector or working head 20 at a predetermined ultrasonic frequency.

[0029] A tubular member 32, coaxial with the transducer axis 16, traverses the transducer assembly 12 and terminates at a proximal end face 34 with an internally threaded receptacle 36 on the distal end of the forward driver 14 for receiving an externally threaded connector 38 at the proximal end of the probe 18. The proximal end face 34 is disposed at an acute probe-to-transducer angle (20°) with respect to the transducer axis 16. The tubular member 32 functions as a liquid guide channel. When the end effector 20 is configured as a debridement head, the tubular member 32 guides a slurry of irrigant and organic particles from the surgical site to a debris collector or trap (not shown) and to a source of suction (not shown). At the proximal end, the tubular member 32 is connected to and passes through an end cap assembly 40 and has a fitting 42 for coupling to a hose (not shown) that runs to a debris collector. The end cap assembly 40 has an electrical connector 43 for coupling to a cable (not shown) from an ultrasonic waveform generator (not shown).

[0030] As shown in Figures 2-4 and 6, the front driver 14 has an outwardly projecting annular flange 44 (having an O-ring seal 44') at its proximal end and a first outer cylindrical surface 46 at its distal end which is coaxial with the transducer axis 16. The front driver 14 further defines a second outer cylindrical surface 48 at its distal end opposite the outer cylindrical surface 44. The second outer cylindrical surface 48 is coaxial with a longitudinal axis 49 of the probe 18. The axes 16, 49 intersect at a probe-to-transducer angle of 20°. The front driver 14 has two parallel planar outer faces or flats 50, 52 extending parallel to the transducer axis 16, each of which articulates with the cylindrical outer faces 46, 48 along a corresponding edge or intersection point 54, 56, 58, 60 (see FIGS. 8 and 9). The front driver 14 further presents three articulated faces or surfaces 62 (FIG. 4) extending between the annular flange 44 at the proximal end and the angled cylindrical surface 48 at the distal end, one of which is planar and two of which are cylindrical arcs.

[0031] 6, the handpiece casing 10 is formed at its distal end with a first inner cylindrical surface 64 coaxial with the transducer axis 16 and a second inner cylindrical surface 66 coaxial with the probe axis 49. These surfaces 64, 66 are closely juxtaposed with the corresponding front driver outer surfaces 46, 48 and are in parallel relationship to each other.

[0032] With respect to the connection between the sheath 22 and the handpiece casing 10, the sheath is provided at its proximal end with an annular sealing member 96 (FIG. 10) that engages against the distal face 70 (FIGS. 8 and 9) of the handpiece casing 10. As described below, the sealing member 96 may be implemented as an annular outwardly extending flange of the diaphragm seal 92 when liquid irrigant is supplied to the space 88 between the sheath 22 and the probe 18.

[0033] The sheath 22 is provided with a pair of occlusion or locking members at its proximal end in the form of two radially inwardly projecting arcuate flanges or ribs 72, 74 (FIG. 10) that extend in a plane transverse to the sheath axis (typically, but not necessarily, the probe axis 49), while the handpiece casing 10 is formed with a pair of cooperating occlusion or locking members at its distal end in the form of two annular open channels or grooves 76, 78 (see FIG. 6), each having one end tapered and defined by a respective cam surface 80.

[0034] The cam surfaces 80 are disposed along the distal side of their respective annular open channels 76 and face proximally toward the handpiece casing 10 .

[0035] At least two sets of cooperating occlusion members 72, 74 and 76, 78 are disposed on the sheath 22 and the handpiece casing 10, although three or more sets of occlusion members may be provided. The annular seal member 96 is made of a resilient compressible material, such as silicone rubber, exhibiting a suitable surface coefficient of friction. The occlusion members 72, 74, 76 are mutually configured to frictionally lock the sheath 22 to the handpiece casing 10 by compressing the annular seal member 96. Locking and unlocking of the sheath 22 to the handpiece casing 10 is accomplished by twisting the sheath in opposite angular orientations (clockwise, counterclockwise) relative to the handpiece. Thus, the cam mechanism, including the flanges 72, 74 and respective corresponding cam surfaces 80, not only allows for frictional locking enhanced by compression, but also allows for rapid coupling and similarly rapid uncoupling of the sheath 22 to the handpiece 10. Thus, the handpiece casing 10 may be secured to the sheath 22 by a single locking mechanism consisting of the annular sealing member 96 and the first and second occlusion members 72, 74 and 78, 80. If no liquid irrigant is provided between the sheath 22 and the probe 18, the sealing members may have a cloverleaf-like leaflet configuration or may have a simple circular shape.

[0036] As shown in Figures 1 and 2, the sheath 22 has two portions: a proximally located main body 82 made from a rigid polymeric material, and a tapered distal end portion 84 made from a flexible or resilient material such as a silicone polymer. The sheath 22 is provided with a port or fitting 86 near the proximal end that is connectable to a source of pressurized liquid coolant (not shown) for flowing the pressurized liquid coolant into a tubular space 88 between the probe 18 and an inner surface 90 of the sheath. As shown in Figures 2 and 10, a diaphragm seal 92 is disposed within the proximal end of the sheath 22 proximal to the port or fitting 86. The diaphragm seal 92 has an annular outer surface 93 disposed along the inner surface 90 of the sheath 22, and at the distal end is provided with an inwardly extending annular flange 94 that circumferentially engages an outer surface of the probe 18 (not separately designated) in a fluid-tight seal.

[0037] The diaphragm seal 92 has an annular shape at the proximal end of the sheath that conforms to the shape of the sheath inner surface 90. The diaphragm seal 92 is preferably spaced generally from the probe 18, except for an inwardly extending annular flange 94. The diaphragm seal 92, as described above, functions to eliminate any painful or uncomfortable sensations that may be felt by a user when grasping the proximal end portion of the sheath. The diaphragm seal 92 further includes an outwardly extending annular flange at the proximal end that functions as a seal member 96 and is clamped between a proximal end face of the sheath (not specifically referenced in the drawings) and a distal end face 70 of the handpiece casing 10 (FIGS. 6 and 8-10).

[0038] As described above, the tubular member 32 extends through the transducer assembly 12 to the proximal end face 34 of the threaded receptacle 36. The tubular member 32 has a lumen 100 having a uniform cross-section with a distal end opening 102 in the plane of the receptacle end face 34. The probe 18 has a longitudinal bore or channel 98 having a proximal end opening 104 of smaller cross-section than the distal end opening 102 or the cross-section of the tubular member 32. The probe bore 98 is aligned with the distal end opening 102 of the tubular member 32. The lumen 100 and the bore or channel 98 together define a continuous passageway without a distally facing shoulder at the junction of the tubular member 32 and the probe bore 98.

[0039] As shown in Figures 11-14, a cradle 106 for use in manually mounting a probe 18 to a handpiece casing 10 at an acute angle (e.g., 20°) relative to the transducer or handpiece axis 16 includes a rectangular container or frame 108 having an open top surface 110 and a support 112, such as an internal surface or crossbar of the frame, that holds the handpiece casing at an acute angle relative to a bottom surface 114 of the frame. The container or frame 108 is placed on a horizontal surface, such as a table top (not shown), with the bottom surface 114 in contact with the horizontal surface. The container or frame 108 is provided with stabilizing rods or bars 118 that extend outwardly from both sides of the container. The stabilizing rods 118 are positioned with their undersides (not separately listed) in the plane of the cradle bottom surface 114.

[0040] To attach the probe 18 to the handpiece casing 10, the user manually screws the probe's connector 38 into the receptacle 36. This step can be performed after the handpiece casing 10 is placed into the container, i.e., in the frame 108, but is preferably performed prior to such placement. The frame 108 has a wall 116 at one end which serves as a stop engageable with the forward or distal end of the handpiece casing 10. The wall or stop 116 has a slot 122 (see also Figures 8 and 9) for receiving the distal end portion of the front driver 14 that projects outward from the casing 10. The slot 122 allows the user access to the front driver 14. To tighten the probe 18 onto the front driver 14 and thus against the casing 10, a torque wrench 120 (FIG. 14) is rotated about the probe axis 49 while the casing 10 and cradle 108 are pressed against a horizontal table top. Application of torque is facilitated by a stabilizing rod 118. The wrench 120 is of the type having a torque detector which automatically stops further rotational driving of the wrench once a preselected amount of torque is reached.

[0041] The ultrasonic surgical instrument of the present invention provides for safe and effective removal of hard tissue such as bone in minimally invasive surgery under microscopic or loop magnification, with the working end of the instrument inserted through a tubular retractor or cannula having an inner diameter as small as 18 mm and a probe length up to 80 mm. The instrument is also available with other types of retractors.

[0042] Ultrasonic surgical instruments according to the present invention may have an outer diameter of less than 10 mm at the tissue access area, with a maximum working length of the instrument of 165 mm. The angled design (20°) provides a direct field of view on the distal end of the instrument that is compatible with microscope setups (microscope focal length is approximately 300 mm).

[0043] An ultrasonic surgical instrument according to the present invention preferably has a combined handpiece and probe length suitable for full wave (two half waves) operation at a frequency of about 23 KHz, with the tapered transition portion located 1 / 4 wavelength length from the proximal end of the handpiece. Thus, the resonator assembly may be comprised of a 1 / 4 wave handpiece and a 3 / 4 wave probe, with the probe joined near the first nodal plane.

[0044] The present invention contemplates a viable ultrasonic handpiece-probe assembly having a probe connected to the handpiece at an acute angle near the nodal plane. In contrast, the prior art (see U.S. Pat. No. 5,222,937) teaches that the beveled connection must be located at the anti-node (loop). If the handpiece is not beveled, the beveled feature must be made in the length of the probe or else a beveled adapter must be provided. As described in the prior U.S. Pat. No. 5,222,937, the connection at the loop (i.e., anti-node) is required to avoid breaking the "threaded connection". It is noted that the amplitude of motion in the inventive instrument is within the same range as the prior art (100 μm to 300 μm) and the assembly does not break.

[0045] 15, the sheath 22 is provided with at least one circular array of circumferentially spaced projections or nubs 124 extending inwardly along the inner surface 90 from the inner surface 90 toward the probe 18 to provide separation or spacing between the sheath and the probe while allowing irrigation agent to flow distally from the port or fitting 86 to the distal sheath tip 24. The array of circumferentially spaced projections 124 is located near the second nodal plane of the transducer-probe ultrasonic resonator.

[0046] Although the present invention has been described in terms of specific embodiments and specific applications, those skilled in the art may, in light of this teaching, generate additional embodiments and additional modifications without departing from the spirit and without exceeding the scope of the claimed invention. It is therefore understood that the drawings and descriptions herein are presented by way of example to facilitate understanding of the invention and should not be construed as limiting the scope of the invention.

Claims

1. 1. An ultrasonic surgical instrument comprising: A handpiece and an electromechanical transducer assembly disposed within the handpiece, the electromechanical transducer assembly including a forward driver and having a longitudinal axis; a probe operatively connected to the forward driver at an angle to the longitudinal axis, the probe having a distal end with an end effector; a sheath surrounding the probe and connected to the handpiece at a proximal end, the end effector configured to extend distally beyond a distal tip of the sheath; an annular sealing member configured to engage a portion of a distal surface of the handpiece and to be clamped between a proximal surface of the sheath and the distal surface of the handpiece.

2. The ultrasonic surgical instrument of claim 1 , wherein the probe is connected to the front driver near a nodal plane.

3. At least two first occlusion members on a distal surface of the handpiece; The ultrasonic surgical instrument of claim 1 , further comprising a corresponding number of second occlusion members on the proximal end of the sheath.

4. The at least two first occlusion members include radially extending protrusions, The ultrasonic surgical instrument of claim 3 , wherein each of the second obstruction members is in the form of an annular open channel having one tapered end defined by a cam surface.

5. An ultrasonic surgical instrument as described in claim 4, wherein the protrusion is an annular rib extending in a plane transverse to the axis of the sheath.

6. An ultrasonic surgical instrument as described in claim 4, wherein the cam surface is positioned along the distal side of the annular open channel and faces proximally toward the handpiece.

7. The annular sealing member is made from a resiliently compressible material; 4. The ultrasonic surgical instrument of claim 3, wherein the at least two first and second occlusion members are configured to frictionally lock the sheath to the handpiece by compressing the annular seal member.

8. The handpiece is fixed to the sheath by a single locking mechanism, The ultrasonic surgical instrument of claim 7 , wherein the single locking mechanism includes the annular sealing member, the at least two first occlusion members, and the second occlusion member.

9. An ultrasonic surgical instrument as described in claim 1, wherein the annular sealing member is positioned radially spaced from a portion of the handpiece and the probe.

10. The ultrasonic transducer assembly is configured to generate ultrasonic vibration energy at a predetermined frequency capable of causing reciprocating motion of the end effector; 2. The ultrasonic surgical instrument of claim 1, wherein the handpiece has a length of one-quarter wavelength of the predetermined frequency and the probe has a length of three-quarter wavelength of the predetermined frequency to facilitate the reciprocating motion of the end effector.

11. The probe includes an externally threaded proximal end; the forward driver includes an internally threaded receptacle at its distal end and is configured to receive the externally threaded proximal end of the probe; The ultrasonic surgical instrument of claim 1 , wherein the internally threaded receptacle has a proximal end face disposed at an angle relative to the longitudinal axis.

12. 1. An ultrasonic surgical instrument comprising: a handpiece defining a longitudinal axis; an electromechanical transducer assembly disposed within the handpiece, the electromechanical transducer assembly including a front driver; a probe operatively connected to the forward driver at an acute angle relative to the longitudinal axis, the probe having a distal end with an end effector, the electromechanical transducer assembly configured to generate ultrasonic vibrational energy that can be supplied to the probe; a sheath surrounding the probe and connected to the handpiece at a proximal end, the end effector extending distally beyond the distal tip of the sheath, the sheath having a port near the proximal end connectable to a source of pressurized liquid coolant for flowing the liquid into a tubular space between the probe and an inner surface of the sheath; a diaphragm seal disposed near the proximal end of the sheath; The diaphragm seal is an annular outer surface that contacts the inner surface of the sheath and forms a fluid-tight seal against the inner surface; an inwardly extending annular flange that contacts the probe and forms a fluid-tight seal; The ultrasonic surgical instrument, wherein the diaphragm seal is configured to reduce sensations felt by a user grasping a proximal portion of the sheath when the ultrasonic transducer assembly is generating the ultrasonic vibrational energy.

13. The ultrasonic surgical instrument of claim 12, wherein the diaphragm seal includes an annular sealing member at a proximal end thereof clamped between a proximal end face of the sheath and a distal end face of the handpiece.

14. The ultrasonic surgical instrument of claim 12, wherein the diaphragm seal is spaced apart from the probe except for the inwardly extending annular flange.

15. The sheath has a main body at a proximal end made of a rigid material; The ultrasonic surgical instrument of claim 12, wherein the sheath further includes a distal end portion made from a silicone polymer.

16. the front driver has two parallel planar outer surfaces extending parallel to the longitudinal axis of the transducer assembly; The ultrasonic surgical instrument of claim 15, wherein each of the two parallel planar outer surfaces is articulated to a first outer cylindrical surface and a second outer cylindrical surface.

17. 13. The ultrasonic surgical instrument of claim 12, wherein the handpiece defines a first inner cylindrical surface at a distal end coaxial with the longitudinal axis of the transducer assembly and further defines a second inner cylindrical surface coaxial with the longitudinal axis of the probe.

18. The ultrasonic surgical instrument of claim 12, wherein the probe is connected to the front driver near a nodal plane.

19. The ultrasonic transducer assembly is configured to generate ultrasonic vibrational energy at a predetermined frequency capable of causing reciprocating motion of the end effector; 13. The ultrasonic surgical instrument of claim 12, wherein the handpiece has a length of one-quarter wavelength of the predetermined frequency and the probe has a length of three-quarter wavelength of the predetermined frequency to facilitate the reciprocating motion of the end effector.

20. The probe includes an externally threaded proximal end; the forward driver includes an internally threaded receptacle at its distal end and is configured to receive the externally threaded proximal end of the probe; The ultrasonic surgical instrument of claim 12, wherein the internally threaded receptacle has a proximal end face disposed at an angle relative to the longitudinal axis.

21. An apparatus comprising: a handpiece defining a longitudinal axis; a sheath coupled to a distal end of the handpiece, the sheath defining an internal lumen; a probe disposed within the lumen, the probe and the sheath extending from the distal end of the handpiece at an angle relative to the longitudinal axis, the probe including an end effector configured to be disposed distal to the sheath when the probe is disposed within the lumen; an ultrasonic transducer assembly disposed within the handpiece and coupled to the probe, the ultrasonic transducer assembly configured to generate ultrasonic vibrational energy at a predetermined frequency capable of causing reciprocating motion of the end effector; the handpiece having a length of one-quarter wavelength of the predetermined frequency and the probe having a length of three-quarter wavelength of the predetermined frequency to facilitate the reciprocating motion of the end effector.

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