Ultrasonic transducer assembly and ultrasonic surgical instrument incorporating the same

Abstract

An ultrasonic transducer assembly of an ultrasonic surgical instrument includes a piezoelectric stack, an ultrasonic horn secured to and extending distally from the piezoelectric stack, and an outer housing. The ultrasonic horn includes a body and a nose portion extending distally from the body. The outer housing is disposed about the piezoelectric stack and the body of the ultrasonic horn. The outer housing defines a distal opening through which the nose portion of the ultrasonic horn extends. The outer housing is hermetically sealed to the ultrasonic horn about the distal opening to define a hermetically sealed interior that encloses the piezoelectric stack and the body of the ultrasonic horn therein.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to ultrasonic surgical instruments, and more particularly to an ultrasonic transducer assembly and an ultrasonic surgical instrument including the same. BACKGROUND

[0002] Ultrasonic surgical instruments utilize ultrasonic energy (i.e., ultrasonic vibrations) to treat tissue. More particularly, ultrasonic surgical instruments utilize mechanical vibratory energy transmitted at ultrasonic frequencies to coagulate, cauterize, fuse, seal, cut, desiccate, and / or fulgurate tissue to achieve hemostasis.

[0003] Ultrasonic surgical instruments typically employ a transducer coupled to a handle of the ultrasonic surgical instrument and configured to generate ultrasonic energy for transmission along a waveguide to an end effector of the ultrasonic surgical instrument designed to treat tissue with the ultrasonic energy. The transducer can be driven by an ultrasonic generator on-board, e.g., on or within the handle of the ultrasonic surgical instrument, or remotely disposed, e.g., as a set-top box connected to the ultrasonic surgical instrument via a surgical cable. The end effector of the ultrasonic surgical instrument can include a blade that receives ultrasonic energy from the waveguide for application to tissue and a clamp member configured to clamp tissue between the blade and the clamp member to facilitate treatment thereof. SUMMARY

[0004] As used herein, the term“distal” refers to the portion of the description that is further from the user, while the term“proximal” refers to the portion of the description that is closer to the user. Further, to the consistent extent, any or all aspects described herein can be used in conjunction with any or all other aspects described herein.

[0005] According to aspects of the present disclosure, an ultrasonic transducer assembly of an ultrasonic surgical instrument is provided. The ultrasonic transducer assembly includes a piezoelectric stack, an ultrasonic horn, and a housing. The ultrasonic horn is fixed to the piezoelectric stack and extends distally therefrom. The ultrasonic horn includes a body and a nose portion extending distally from the body. The housing is disposed about the piezoelectric stack and the body of the ultrasonic horn. The housing defines a distal opening through which the nose portion of the ultrasonic horn extends and is hermetically sealed to the ultrasonic horn about the distal opening to define a hermetically sealed interior enclosing the piezoelectric stack and the body of the ultrasonic horn therein.

[0006] In aspects of the present disclosure, the housing is welded to the ultrasonic horn along a weld joint that surrounds the distal opening. In such aspects, the ultrasonic horn can include a flange disposed between the body and the nose. The flange is disposed within the hermetically sealed interior, proximate the distal opening and overlapping the weld joint.

[0007] In another aspect of the present disclosure, the housing is hermetically sealed to the ultrasonic horn at a node along the ultrasonic horn.

[0008] In still another aspect of the present disclosure, the housing includes at least two housing components that are hermetically sealed to one another. In such aspects, the at least two housing components can be welded to one another along at least one additional weld joint. Further, one of the at least two housing components can include a flange disposed within the hermetically sealed interior and overlapping the at least one additional weld joint.

[0009] In yet another aspect of the present disclosure, a contact assembly is hermetically sealed within one or more windows defined by the housing. The contact assembly includes a plurality of contacts that extend from the hermetically sealed interior to an exterior of the housing. In such aspects, the contact assembly can further include a frame that electrically isolates the plurality of contacts from the housing.

[0010] In still yet another aspect of the present disclosure, at least one contact of the contact assembly is configured to transmit a drive signal to the hermetically sealed interior and / or at least another contact is configured to transmit a data signal from the hermetically sealed interior.

[0011] An ultrasonic surgical instrument according to aspects of the present disclosure includes a handle assembly and an elongate assembly. The handle assembly includes a housing and an ultrasonic transducer assembly according to any of the aspects detailed above or elsewhere herein. The elongate assembly extends distally from the handle assembly. The elongate assembly includes a waveguide configured to engage the nose of the ultrasonic horn and define a blade at a distal end thereof. Ultrasonic energy generated by the piezoelectric stack is transmitted along the ultrasonic horn and the waveguide to the blade for treating tissue in the vicinity of the blade.

[0012] In aspects of the present disclosure, a contact assembly is hermetically sealed within one or more windows defined by the housing. The contact assembly includes a plurality of sliding contacts extending from the hermetically sealed interior to an exterior of the housing. In such aspects, each of a plurality of ring contacts disposed within the handle assembly can be configured to be slidably coupled to a corresponding sliding contact of the plurality of sliding contacts. At least one pair of ring contacts and corresponding sliding contacts can be configured to transmit a drive signal to the hermetically sealed interior. Additionally or alternatively, at least one pair of ring contacts and corresponding sliding contacts can be configured to transmit a data signal from the hermetically sealed interior. BRIEF DESCRIPTION OF DRAWINGS

[0013] The above and other aspects and features of the present disclosure will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters identify like or similar elements throughout.

[0014] Figure 1 is a side perspective view of an ultrasonic surgical instrument provided in accordance with the present disclosure;

[0015] Figure 2 is Figure 1 is a magnified side longitudinal cross-sectional view of a proximal portion of the ultrasonic surgical instrument of

[0016] Figure 3 is Figure 1 is a magnified front perspective view of a transducer assembly of the ultrasonic surgical instrument of

[0017] Figure 4 is Figure 1 is a magnified front perspective view of a transducer assembly of the ultrasonic surgical instrument of

[0018] Figure 5 is Figure 4 is a magnified perspective view of the detail area indicated with "5" in

[0019] Figure 6 is Figure 4 is a magnified side view of the detail area indicated with "6" in DETAILED DESCRIPTION

[0020] Reference Figure 1 and 2An ultrasonic surgical instrument provided in accordance with the present disclosure is generally indicated by the reference numeral 10. The ultrasonic surgical instrument 10 includes a handle assembly 100 and an elongate assembly 200 extending distally from the handle assembly 100. The handle assembly 100 includes a housing 110 defining a body portion 112 and a fixed handle portion 114. The handle assembly 100 further includes an activation button 120 and a clamp trigger 130.

[0021] The body portion 112 of the housing 110 is configured to support an ultrasonic transducer and generator assembly ("TAG") 300 including a generator assembly 310 and an ultrasonic transducer assembly 320. The TAG 300 can be permanently engaged with or removable from the body portion 112 of the housing 110. The generator assembly 310 includes a housing 312 configured to house internal electronics of the generator assembly 310 and a cradle 314 configured to rotatably support the ultrasonic transducer assembly 320. Alternatively, the generator assembly 310 can be remotely located and coupled to the ultrasonic surgical instrument 10 by a surgical cable. The TAG 300 is described in greater detail below.

[0022] The fixed handle portion 114 of the housing 110 defines a compartment 116 configured to receive a battery assembly 400 and a door 118 configured to enclose the compartment 116. An electrical connection assembly 140 is disposed within the housing 110 of the handle assembly 100 and is used to electrically couple the activation button 120, the generator assembly 310 of the TAG 300 and the battery assembly 400 to one another when the TAG 300 is supported on or in the body portion 112 of the housing 110 and the battery assembly 400 is disposed within the compartment 116 of the fixed handle portion 114 of the housing 110, thereby enabling the ultrasonic surgical instrument 10 to be activated in response to the activation button 120 being depressed. In embodiments where the generator assembly 310 is remote from the ultrasonic surgical instrument 10, the battery assembly 400 and the configuration of the fixed handle portion 114 for receiving the battery assembly 400 need not be provided, as the generator assembly 310 can be powered by a standard wall outlet or other power source.

[0023] Still referring to Figure 1 and Figure 2, the elongate assembly 200 of the ultrasonic surgical instrument 10 includes an outer drive sleeve 210, an inner support sleeve 220 disposed within the outer drive sleeve 210, a waveguide 230 extending through the inner support sleeve 220, a drive assembly 250, a rotation knob 270, and an end effector 280 including a blade 282 and a clamp jaw 284. A proximal portion of the outer drive sleeve 210 is operably coupled to the clamp trigger 130 of the handle assembly 100 by the drive assembly 250, while a distal portion of the outer drive sleeve 210 is operably coupled to the clamp jaw 284. As such, the clamp trigger 130 is selectively actuatable to thereby move the outer drive sleeve 210 about the inner support sleeve 220 to pivot the clamp jaw 284 relative to the blade 282 of the end effector 280 from a spaced apart position to an approximated position for clamping tissue between the clamp jaw 284 and the blade 282. The drive assembly 250 provides a force limiting feature thereby limiting the clamp pressure applied to the tissue to a particular clamp pressure or within a particular clamp pressure range. The rotation knob 270 is rotatable in either direction to rotate the elongate assembly 200 relative to the handle assembly 100 in either direction.

[0024] The waveguide 230 extends through the inner support sleeve 220. The waveguide 230 defines a body 232 and a blade 282 extending distally from the body 232. The blade 282 functions as a blade of the end effector 280. The waveguide 230 further includes a proximal threaded male connector 236 configured for threaded engagement within a threaded female receiver 325e of a nose 325b of an ultrasonic horn 324 of the ultrasonic transducer assembly 320 such that ultrasonic vibrations generated by the ultrasonic transducer assembly 320 are transmitted along the waveguide 230 to the blade 282 for treatment of tissue clamped between the blade 282 and the clamp jaw 284 or positioned adjacent to the blade 282.

[0025] Referring to Figures 2-4 , the ultrasonic transducer assembly 320 includes a piezoelectric stack 322, an ultrasonic horn 324, a bolt 328( Figure 4 ), a proximal nut 329( Figure 4), first and second electrode assemblies 330, a contact assembly 332, and a housing 340. The bolt 328 secures the piezoelectric stack 322 between the ultrasonic horn 324 and the proximal nut 329. The first and second electrode assemblies 330 are disposed between the piezoelectric elements 323 of the piezoelectric stack 322 and are connected to the contact assembly 332. The contact assembly 332 enables the transmission of drive and / or data signals between, for example, the piezoelectric stack 322 and the generator assembly 310 through the housing 340. The housing 340, along with the ultrasonic horn 324, defines a hermetically sealed enclosure having an interior 341 that houses the piezoelectric stack 322, portions of the ultrasonic horn 324, the bolt 328, the proximal nut 329, the first and second electrode assemblies 330, and portions of the contact assembly 332.

[0026] The ultrasonic transducer assembly 320 further includes a rotation knob 350 mounted on or formed with the housing 340 at a proximal end of the housing 340. Figure 1 The knob 350 is accessible from the exterior of the handle assembly 100 and is configured for manual rotation to rotate the ultrasonic transducer assembly 320 relative to the generator assembly 310 and the housing 110.

[0027] With continued reference to Figure 1 and Figure 2The generator assembly 310 includes a plurality of annular contacts 364, 366, 368 that surround the ultrasonic transducer assembly 320 and are disposed in slidable contact with corresponding sliding contacts 334, 336, 338, respectively, of the contact assembly 332 of the ultrasonic transducer assembly 320. Thus, the annular contacts 364, 366, 368 and the corresponding sliding contacts 334, 336, 338 define a sliding annular contact assembly that enables the transmission of drive and / or data signals between the generator assembly 310 and the piezoelectric stack 322 of the ultrasonic transducer assembly 320 regardless of the rotational orientation of the ultrasonic transducer assembly 320 relative to the generator assembly 310. More specifically, with respect to drive signal communication, a first one of the electrode assemblies 330 includes at least one positive electrode disposed between a piezoelectric element 323 of the piezoelectric stack 322 and an electrode connector connecting the at least one positive electrode with the sliding contact 334, which in turn is disposed in contact with the annular contact 364. A second one of the electrode assemblies 330 includes at least one negative electrode disposed between a piezoelectric element 323 of the piezoelectric stack 322 and an electrode connector connecting the at least one negative electrode with the sliding contact 336, which in turn is disposed in contact with the annular contact 366. In this manner, a drive signal voltage can be applied from the generator assembly 310 to the piezoelectric elements 323 of the piezoelectric stack 322 through the positive and negative electrodes. The piezoelectric stack 322, in turn, converts the applied voltage into mechanical energy in the form of ultrasonic vibrations that are transmitted to the ultrasonic horn 324. In other embodiments, the second one of the electrode assemblies 330 is omitted and the housing 340 is used as the negative electrode for the piezoelectric stack 322.

[0028] With respect to data signal communication, the contact assembly 332 can include a data chip (not explicitly shown) (or an electrical connector, where the data chip is disposed within the generator assembly 310) disposed in communication with the ultrasonic horn 324 (and / or other portions of the ultrasonic transducer assembly 320). The data chip, more particularly, can be a microprocessor chip or other suitable chip having sensing circuitry to detect various conditions, parameters, characteristics, etc. of the piezoelectric laminate 322, the ultrasonic horn 324, and / or other portions of the ultrasonic transducer assembly 320. The data chip can be configured to sense, for example, the frequency, amplitude, impedance, and / or temperature of the ultrasonic horn 324 (or other portions of the ultrasonic transducer assembly 320); the number of times the ultrasonic transducer assembly 320 has been activated, the duration of activation of the ultrasonic transducer assembly 320, etc. The data chip can additionally or alternatively include a memory that stores information related to the ultrasonic transducer assembly 320, such as a model number, a serial number, a date of manufacture, calibration and / or testing information, manufacturer setup information, etc. In embodiments where the data chip includes sensor circuitry, the memory can also store sensed data.

[0029] The data chip (or electrical connector) within the ultrasonic transducer assembly 320 is coupled to the sliding contact 338 of the contact assembly 332, which is in turn disposed in contact with the annular contact 368 to enable data signal communication between the ultrasonic transducer assembly 320 and the ultrasonic generator assembly 310.

[0030] The ultrasonic horn 324 includes a body 325a disposed within the housing 340 of the ultrasonic transducer assembly 320, and a nose 325b extending distally from an exterior of the body 325a of the housing 340 of the ultrasonic transducer assembly 320. A proximal collar 325c is disposed between the body 325a and the nose 325b, and an annular outwardly facing contact surface 325d is disposed proximally adjacent the nose 325b to facilitate the formation of an airtight seal between the housing 340 and the ultrasonic horn 324, as discussed in greater detail below. The annular outwardly facing contact surface 325d can be disposed at or near a node along the ultrasonic horn 324. The nose 325b of the ultrasonic horn 324 defines a distal threaded female receiver 325e configured to releasably threadably engage the waveguide 230 with the ultrasonic horn 324. The ultrasonic horn 324 can be formed of a metal, such as titanium, aluminum, stainless steel, amorphous metal, or other suitable material.

[0031] Referring to Figures 3-6As described above, the housing 340 of the ultrasonic transducer assembly 320 defines a hermetically sealed enclosure having an interior 341 that houses the piezoelectric stack 322, portions of the ultrasonic horn 324, the bolt 328, the proximal end nut 329, the first and second electrode assemblies 330, and portions of the contact assembly 332. The housing 340 can be formed of a metal, such as titanium, aluminum, stainless steel, amorphous metal, or other suitable material. The housing 340 can be formed of multiple housing components, including, for example, a proximal end cap portion 342, one or more intermediate tube portions 344, and a distal end cap portion 346. The proximal end cap portion 342 defines a closed proximal end and an open distal end, the intermediate tube portions 344 define open proximal and distal ends, and the distal end cap portion 346 defines an open proximal end and a smaller diameter opening 347 at its distal end. The distal end cap portion 346 further defines an annular inwardly facing contact surface 348 around the smaller diameter opening 347. The housing 340 further includes one or more windows 349 defined therethrough for sealing the contact assembly 332 therein, as described in detail below.

[0032] The distal end of the proximal end cap portion 342 and the proximal end of the proximal-most intermediate tube portion 344 abut one another to define a joint 343a, and are annularly welded to one another around the joint 343a to secure and hermetically seal the distal end of the proximal end cap portion 342 and the proximal end of the proximal-most intermediate tube portion 344 to one another. One of the distal end of the proximal end cap portion 342 or the proximal end of the proximal-most intermediate tube portion 344 includes an overlapping flange (not explicitly shown, see flange 345b( Figure 6 )) on the inside of the joint 343a. The flange protects the interior 341 of the housing 340 (and any components disposed therein) by overlapping the joint 343a when the joint 343a is welded to secure and hermetically seal the distal end of the proximal end cap portion 342 and the proximal end of the proximal-most intermediate tube portion 344 to one another. Other suitable methods of securing and hermetically sealing the distal end of the proximal end cap portion 342 and the proximal end of the proximal-most intermediate tube portion 344 to one another in lieu of welding also encompass, for example, press-fitting, use of O-rings, adhesives, etc.

[0033] The distal end of the distal-most intermediate tube portion 344 and the proximal end of the distal end cap portion 346 abut one another to define a joint 343b, and are annularly welded to one another around the joint 343b to secure and hermetically seal the distal end of the distal-most intermediate tube portion 344 and the proximal end of the distal end cap portion 346 to one another. One of the distal end of the distal-most intermediate tube portion 344 or the proximal end of the distal end cap portion 346 includes an overlapping flange (not explicitly shown, see flange 345b( Figure 6)) to protect the interior 341 of the housing 340 when the weld joint 343b is welded to secure and hermetically seal the distal end of the distal-most intermediate tube section 344 and the proximal end of the distal cap section 346 to one another.

[0034] Turning to Figure 6 In embodiments in which multiple intermediate tube sections 344 are provided, the abutting ends of adjacent intermediate tube sections 344 can be welded to one another in similar fashion as described above, e.g., with the flanges 345b overlapping the weld joints 345a on their inner sides. As an alternative to including proximal, intermediate, and distal sections 342, 344, 346 that are welded to one another about annular joints, respectively, the housing 340 can include left and right halves that are welded to one another along longitudinal joints, for example, or can include any suitable combination of components welded to one another by annular and / or longitudinal joints (and including annular and / or longitudinal interior flanges). In other embodiments, the housing 340 is formed as a single monolithic piece of material.

[0035] With particular reference back to Figure 5 To fully enclose and hermetically seal the interior 341 of the housing 340, and thus the piezoelectric stack 322, portions of the ultrasonic horn 324, the bolt 328, the proximal nut 329, the first and second electrode assemblies 330, and portions of the contact assembly 332 within the housing 340, the distal cap section 346 of the housing 340 is positioned so that the ultrasonic horn 324 extends through the smaller-diameter opening 347. More specifically, the housing 340 and the ultrasonic horn 324 are positioned so that the ultrasonic horn 324 extends through the smaller-diameter opening 347 with the proximal collar 325c abutting the inner surface of the housing 340 adjacent the smaller-diameter opening 347, and so that the outward-facing contact surface 325d and the inward-facing contact surface 348 abut one another to define the joint 327. The distal cap section 346 of the housing 340 and the ultrasonic horn 324 are annularly welded to one another about the joint 327 to secure and hermetically seal the distal end of the distal cap section 346 and the ultrasonic horn 324 to one another. The proximal collar 325c overlaps the joint 327 on its inner side to protect the interior 341 of the housing 340 (and any components disposed therein) when the weld joint 327 is welded to secure and hermetically seal the distal cap section 346 of the housing 340 and the ultrasonic horn 324 to one another. As described above, the annular outward-facing contact surface 325d of the ultrasonic horn 324 can be disposed at a node along the ultrasonic horn 324, and thus, in the same manner, the joint 327 (the location at which the housing 340 is connected to the ultrasonic horn 324) is disposed at a node along the ultrasonic horn 324 to render the housing 340 ultrasonically inert.

[0036] With reference to Figure 2 and Figure 4As noted above, the contact assembly 332 includes sliding contacts 334, 336, 338 that extend from the interior 341 of the housing 340 to its exterior. More specifically, the contacts 334, 336, 338 project radially outward beyond the outer surface of the housing 340 to enable slidable contact with corresponding annular contacts 364, 366, 368 of the generator assembly 310, respectively, without the housing 340 contacting the annular contacts 364, 366, 368. Moreover, since the housing 340 is formed of an electrically conductive material, such as metal, the contact assembly 332 further includes an electrically insulating bezel 333 that hermetically retains the contacts 334, 336, 338 in electrical isolation from each other and the housing 340. The bezel 333 can be formed of a polymer or other suitable electrically insulating material and can be overmolded around the contacts 334, 336, 338 to secure and form a hermetic seal around the bezel, the bezel can be hermetically sealed and secured around the contacts 334, 336, 338 using an epoxy or other seal, or in any other suitable manner. Moreover, the bezel 333 can be overmolded within the window 349 of the housing 340 to secure the contact assembly 332 in the bezel and form a hermetic seal between the contacts 334, 336, 338 (by the same overmolding or additional overmolding that secures and seals the contacts 334, 336, 338), the bezel can be secured and hermetically sealed within the window 349 using an epoxy or other seal, or in any other suitable manner.

[0037] The hermetic sealing of the housing 340 to the ultrasonic horn 324 (and the hermetically sealed contact assembly 332 within the window 349 of the housing 340) detailed above ensures that the transducer assembly 320 can withstand multiple rounds of sterilization, such as autoclaving.

[0038] While several embodiments of the present disclosure have been detailed above and illustrated in the drawings, it will be apparent to those skilled in the art that the disclosure is not limited to these embodiments, but rather the scope of the disclosure is to be as broad as permitted by the art, and construed in the same manner. Accordingly, the above description and accompanying drawings are not to be interpreted in a limiting sense, but merely as exemplifications of specific embodiments. Other modifications will be readily apparent to those skilled in the art with the scope and spirit of the claims appended hereto.

Claims

1. An ultrasonic transducer assembly for an ultrasonic surgical instrument, comprising: piezoelectric stack; An ultrasonic amplitude transformer is fixed to and extends distally from the piezoelectric stack, the ultrasonic amplitude transformer comprising a body and a nose-shaped portion extending distally from the body; as well as A housing is disposed around the body of the piezoelectric stack and the ultrasonic amplitude transformer, the housing defining a distal opening through which the nose portion of the ultrasonic amplitude transformer extends, the housing being hermetically sealed to the ultrasonic amplitude transformer by directly connecting the housing to the ultrasonic amplitude transformer around the distal opening to define a hermetically sealed interior that encloses the piezoelectric stack and the body of the ultrasonic amplitude transformer therein.

2. The ultrasonic transducer assembly of claim 1, wherein the housing is welded to the ultrasonic amplitude transformer along a welded joint surrounding the distal opening.

3. The ultrasonic transducer assembly of claim 2, wherein the ultrasonic amplitude rod includes a flange disposed between the body and the nose portion, the flange being disposed within the hermetically sealed interior, adjacent to the distal opening and overlapping the welded joint.

4. The ultrasonic transducer assembly of claim 1, wherein the housing is hermetically sealed to the ultrasonic transducer at a node along the ultrasonic transducer.

5. The ultrasonic transducer assembly of claim 1, wherein the housing comprises at least two housing components that are hermetically sealed to each other.

6. The ultrasonic transducer assembly of claim 5, wherein the at least two housing components are welded to each other along at least one additional weld joint.

7. The ultrasonic transducer assembly of claim 6, wherein one of the at least two housing components includes a flange disposed within the hermetically sealed interior and overlapping the at least one additional welded joint.

8. The ultrasonic transducer assembly of claim 1, further comprising a contact assembly hermetically sealed within at least one window defined by the housing, the contact assembly comprising a plurality of contacts extending from the interior of the hermetically sealed interior to the exterior of the housing.

9. The ultrasonic transducer assembly of claim 8, wherein the contact assembly further comprises a frame electrically isolating the plurality of contacts from the housing.

10. The ultrasonic transducer assembly of claim 8, wherein at least one contact is configured to transmit a drive signal to the interior of the hermetically sealed enclosure, and wherein at least another contact is configured to transmit a data signal from the interior of the hermetically sealed enclosure.

11. An ultrasonic surgical instrument, comprising: Handle assembly, the handle assembly comprising: case; An ultrasonic transducer assembly supported by the housing, the ultrasonic transducer assembly comprising: piezoelectric stack; An ultrasonic amplitude transformer is fixed to and extends distally from the piezoelectric stack, the ultrasonic amplitude transformer comprising a body and a nose-shaped portion extending distally from the body; as well as A housing is provided surrounding the piezoelectric stack and the body of the ultrasonic amplitude transformer, the housing defining a distal opening, the nose portion of the ultrasonic amplitude transformer extending through the distal opening, the housing being hermetically sealed to the ultrasonic amplitude transformer by directly connecting the housing to the ultrasonic amplitude transformer around the distal opening to define a hermetically sealed interior, the hermetically sealed interior enclosing the piezoelectric stack and the body of the ultrasonic amplitude transformer therein; as well as An elongated assembly extending distally from the handle assembly includes a waveguide configured to engage the nose portion of the ultrasonic amplitude transformer, the waveguide defining a blade at its distal end. The ultrasonic energy generated by the piezoelectric stack is transmitted along the ultrasonic amplitude transformer and the waveguide to the blade for treating tissue near the blade.

12. The ultrasonic surgical instrument of claim 11, wherein the housing is welded to the ultrasonic amplitude transformer along a welded joint surrounding the distal opening.

13. The ultrasonic surgical instrument of claim 12, wherein the ultrasonic amplitude rod includes a flange disposed between the body and the nose portion, the flange being disposed within the airtight seal, adjacent to the distal opening and overlapping the welded joint.

14. The ultrasonic surgical instrument of claim 11, wherein the housing is hermetically sealed to the ultrasonic amplitude transformer at a node along the ultrasonic amplitude transformer.

15. The ultrasonic surgical instrument of claim 11, wherein the housing comprises at least two housing components that are hermetically sealed to each other along at least one additional welded joint.

16. The ultrasonic surgical instrument of claim 15, wherein one of the at least two housing components includes a flange disposed within the hermetically sealed interior and overlapping the at least one additional welded joint.

17. The ultrasonic surgical instrument of claim 11, further comprising a contact assembly hermetically sealed within at least one window defined by the housing, the contact assembly comprising a plurality of sliding contacts extending from the interior of the hermetically sealed interior to the exterior of the housing.

18. The ultrasonic surgical instrument of claim 17, further comprising a plurality of annular contacts disposed within the handle assembly, each annular contact being configured to be slidably coupled to a corresponding sliding contact among the plurality of sliding contacts.

19. The ultrasonic surgical instrument of claim 18, wherein at least one pair of annular contacts and a corresponding sliding contact are configured to transmit a drive signal to the interior of the hermetically sealed area.

20. The ultrasonic surgical instrument of claim 18, wherein at least one pair of annular contacts and a corresponding sliding contact are configured to transmit data signals from inside the hermetically sealed interior.

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