Devices and methods for treating tissues

Abstract

The present invention belongs to the field of medical technology and relates to a device for ablating tissue. It particularly relates to a sonotrode suitable for use with an ultrasonic surgical instrument. The present invention also relates to an ultrasonic surgical instrument for ablating tissue comprising such a sonotrode, as well as a method for manufacturing the sonotrode of the present invention and a method for ablation using the sonotrode of the present invention.

Description

Technical Field

[0001] The present invention belongs to the field of medical technology and relates to a device for performing ablative operations such as filing, scraping, reaming and / or cutting on tissue. The present invention particularly relates to a sonotrode suitable for use with an ultrasonic surgical instrument. Depending on the specific configuration of the sonotrode, the tissue can be hard tissue or soft tissue. Background Art

[0002] The provision of an ultrasonic surgical instrument and the elements that transmit the ultrasonic vibrations coupled into it from one end (usually the proximal end) to the site of action (usually the distal end in contact with the tissue) generally requires the resolution of a number of problems. Such elements are hereinafter referred to as sonotrodes. In particular, the vibration behavior when in contact with the tissue, the mechanical stability, in particular when forces radial to the longitudinal axis of the sonotrode are applied, the localization to the treatment site and / or the controllability, the applicability in situations of different and / or limited spatial conditions, the ability to ablate during forward, backward and / or lateral movement, the ability to file, scrape, ream and / or cut, the removal of debris from the treatment site and cooling are some of the many problems.

[0003] Ultrasonic surgical instruments are used for long-term ablation, especially for cutting soft tissue. Recent improvements have focused on the effective use of ultrasonic surgical instruments to treat hard tissue, especially bone tissue.

[0004] Surgical devices for ultrasonic surgery to treat bone tissue by ablative operations such as filing, scraping, reaming and / or cutting generally include a head which is pressed against the bone tissue for the operation and is set to ultrasonic oscillation. The ablative operations with these instruments are generally based on localized comminution of the bone tissue.

[0005] Commercially available sonotrodes for ultrasonic surgical instruments for ablating bone tissue can be roughly divided into two categories. The first category involves sonotrodes that are primarily configured to cut bone tissue. This first category of sonotrodes typically has a blade-like portion. The second category involves sonotrodes that are configured to shape the surface of bone tissue. This second category of sonotrodes typically has a head that is curved relative to the longitudinal axis of the sonotrode and the ultrasonic surgical instrument. A subclass of the second category of sonotrodes has a distal end that includes a plurality of structures suitable for ablation, such as spikes or edges, and is evenly distributed around the entire distal end of the sonotrode.

[0006] The osteotomy blades of the ultrasonic surgical instrument product line BoneScapel® (Misonix) and Stryker's Bone Tip Knives are examples of the first type of sonotrodes. The BoneScapel® razors and Stryker's Bone Tip Spetzlers and Payners are examples of the second type of sonotrodes.

[0007] The first type of sonotrodes, which means sonotrodes for cutting bone tissue, for example during osteotomy, on the one hand need to be equipped for cutting very dense and solid cortical bone tissue and for use at different angles (because of different approaches). On the other hand, the cutting device needs to be able to cut deeply into cancellous bone tissue, for example. This is why such sonotrodes are blade-shaped, with a blade length usually between 10 mm and 25 mm, a blade width usually between 5 mm and 10 mm, and a blade thickness usually between 0.5 mm and 1 mm. If the blade is considered to consist of two flat surfaces and a circumferential side wall, we usually cut along the side wall of the blade. In an embodiment, the flat surface comprises structures for filing the bone tissue.

[0008] The advantage of the prior art instruments comprising a cutting head with a blade-like portion and an optional rasp head is their applicability in a somewhat restricted treatment area. The main disadvantage of said instruments is their sensitivity to deformation and / or lateral deflection influenced by mechanical forces or resonance of the blade-like portion. For example, this sensitivity to deformation limits the pressure that can be applied between the head and the bone tissue.

[0009] The second type of sonotrode, which means a sonotrode for shaping the surface of bone tissue, is used to provide a well-defined contact surface for the bone tissue to be treated. The contact surface extends significantly in two directions (axial and lateral), with a minimum surface area of ​​only a few square millimeters. The contact surface includes ablative structures and protrudes from the rest of the sonotrode, usually as part of a sonotrode portion that is bent relative to the rest of the sonotrode. Such sonotrodes are disadvantageous in terms of excitation of transverse oscillations, limitation of their working direction, removal of debris from the treatment site and cooling.

[0010] Some of these disadvantages of the second class of sonotrodes can be addressed by evenly distributing the ablative structure around the entire distal end of the sonotrode (the above subclass). However, this leads to further disadvantages, such as reduced localization to the site of action and controllability and applicability in situations with different and / or limited spatial conditions, for example due to the risk of damaging tissue that should not be treated.

[0011] WO2013 / 057179 discloses a sonotrode of a surgical instrument for cutting bone tissue. The sonotrode head is blade-shaped and serves as a cutting device extending in the longitudinal direction. It has a plurality of perforations extending transversely through the sonotrode head. The perforations are elliptical and form an angle of 30° to 80° with the longitudinal direction, whereby the sonotrode head is elastic and performs a pitching movement within a plane defined by the sonotrode head when subjected to ultrasonic vibrations. According to WO2013 / 057179, despite this, sufficient rigidity for applying pressure is retained. The cutting surface of the sonotrode head also includes indentations that facilitate the removal of dissolved bone material.

[0012] US2015 / 0005771A1 describes a sonotrode for cutting tissue such as cartilage and bone. The sonotrode has a planar blade body with two lateral sides and a shallow recess. These sonotrodes have a handle with an outlet communicating with the recess so that liquid can flow into the recess. The blade also has a through hole extending between the side surfaces of the blade body and allowing liquid to flow from the recess to the opposite side of the blade.

[0013] US 2012 / 0004729 A1 describes a cutting instrument with a longitudinal blade having a cutting edge constructed from an edge surrounding an opening extending through the blade. The cutting is performed by rotation rather than oscillation. Summary of the invention

[0014] The object of the present invention is to further improve sonotrodes for ultrasonic surgical instruments. In particular, the object of the present invention is to provide a sonotrode for ultrasonic surgical instruments which meets a number of requirements in a better manner than sonotrodes of the prior art.

[0015] Another object of the present invention is to provide a related ultrasonic surgical instrument.

[0016] An object of the present invention is to provide an improved sonotrode for ultrasonic surgical instruments suitable for ablating hard or soft tissue.

[0017] Another object of the present invention is to provide an improved ultrasonic welding electrode for an ultrasonic surgical instrument, which is suitable for ablating bones, especially ream bones, by means of mechanical vibration; and an ultrasonic surgical instrument, which is used for at least one of ream bones in a forward and / or backward direction, scrape bones, especially scrape bones in the backward direction, and expand bones, especially expand bones in the forward direction; and ultrasonic surgical instruments including the improved ultrasonic welding electrode and related methods for ablating bones and methods for manufacturing these ultrasonic welding electrodes.

[0018] Ultrasonic welding electrodes can be used to ablate cortical bone or uncontrolled bone growth induced, for example, during degenerative diseases such as osteophytes, sclerotic bone changes, and bone tumors.

[0019] For example, sonotrodes can also be used to debride tumor tissue and infected sites in bone.

[0020] One goal to be achieved with an improved sonotrode is to have better ablation performance on cortical bone, especially the performance of filing, scraping and / or reaming. Cortical bone is dense. Therefore, it is envisioned to reduce the heat generated during bone ablation. In addition, it would be advantageous to be able to improve the controllability of the ablation site.

[0021] Another object of the present invention is to provide an improved ultrasonic welding electrode of an ultrasonic surgical instrument, which is suitable for treating soft tissue by ablation using mechanical vibration; and an ultrasonic surgical instrument for abrading at least one of the soft tissues in a forward and / or backward direction, and an ultrasonic surgical instrument including the improved ultrasonic welding electrode and related methods for ablating soft tissue and methods of manufacturing these ultrasonic welding electrodes.

[0022] Wound management, debridement, and abrasion (scraping) of soft tissue are examples of treatments that may be performed by the improved sonotrodes, related ultrasonic surgical instruments, and related methods.

[0023] The improvement of the sonotrode enables the improved sonotrode according to the present invention to be used not only in open surgery but also in minimally invasive surgery (MIS).

[0024] The term "proximal" as used herein refers to the point of attachment closest to the housing of an ultrasonic surgical instrument or a user of the instrument. The term "distal" as used herein refers to the point of attachment farthest from the housing of an ultrasonic surgical instrument or a user of the instrument. Thus, the distal end and the proximal end are opposite ends.

[0025] As used herein, the term "sharp edge" refers to a structure, such as an edge, rim, protrusion, etc., that is configured to ablate tissue. This implies not only that the structural feature is "sharp" to a certain extent, but also implies a specific arrangement of the "sharp edge" in the sonotrode. That is, the sharp edge is arranged to contact tissue during proper use of the sonotrode and ultrasonic surgical instrument, respectively.

[0026] The term "longitudinal axis" is used herein for the central longitudinal axis.

[0027] The term "ablation" includes "filing," "shaving," "shaping," "trimming," "forming," etc. of tissue surfaces, such as the surfaces of bone, ligament, and tumor tissue, and the surfaces of tissue replacement materials and implants.

[0028] The term "sonotrode" is used for tools for treating tissue by using mechanical vibrations (mechanical oscillations), in particular for mechanically treating tissue. The sonotrode is configured to transfer mechanical vibrations coupled to the proximal end of the tool to its distal end, meaning the working head (or "cap" if the nomenclature of the sonotrode according to the invention is used), and to transfer the energy carried by the mechanical vibrations from the head to the tissue. Typically, the sonotrode can be resonantly excited, which means that there is a frequency of mechanical vibrations that resonantly excites the sonotrode.

[0029] The terms "concave" and "convex" are also used herein in a limiting sense of these terms to "concave" or "convex" surfaces and shapes (i.e., any straight line between two points on a concave surface extends outside the body defining the concave surface, and any straight line between two points on a convex surface extends inside the body defining the convex surface), but may also include straight line portions.

[0030] A first aspect of the present invention relates to a sonotrode for an ultrasonic surgical instrument. The sonotrode comprises a longitudinal axis, a shaft extending along the longitudinal axis, and a cap.

[0031] The rod may include any portion of the sonotrode disposed between the distal coupling and the cap.

[0032] The rod may be flexible.

[0033] The rod may have a constant diameter or it may have a varying diameter along the longitudinal axis, such as the tapered (flattened) region discussed above.

[0034] The cap is configured to perform an ablation operation on the tissue using mechanical oscillations (mechanical vibrations), in particular by comprising at least one sharp edge. The tissue may be hard tissue, in particular bone, or soft tissue. In an embodiment, the tissue is bone tissue.

[0035] The sharp edge is arranged on the cap in such a way that it can be placed in contact with the tissue and when mechanical vibrations are applied to the sonotrode along the longitudinal axis it "files" on its surface. In other words, the cap comprises at least one portion protruding radially (radially relative to the longitudinal axis) more than the stem, wherein the at least one portion comprises at least one sharp edge.

[0036] The cap also comprises a surface arranged between the distal end of the rod and the sharp edge of the portion. In other words, the cap comprises a surface, in particular a proximal surface extending from the beginning of the cap at the distal end of the rod to the sharp edge.

[0037] Said surface of the cap is concave and / or it extends at an opening angle of equal to or less than 90 degrees relative to the rod. An opening angle of 90 degrees or less relative to the rod means that the surface has a surface normal in the direction of the longitudinal axis or that the surface extends towards the proximal side from its start at the distal end of the rod.

[0038] Finally, the cap is designed to have a center of mass on the longitudinal axis.

[0039] The ultrasonic welding electrode having the above-mentioned characteristics differs from the ultrasonic welding electrodes of the prior art, in particular the ultrasonic welding electrodes of the first and second types, at least in that the proximal surface is concave or extends at an opening angle equal to or less than 90 degrees relative to the rod and / or the cap has a center of mass located on the longitudinal axis.

[0040] These features bring various advantages, such as:

[0041] The cap with the center of mass on the longitudinal axis reduces the excitation of the transverse modes when mechanical vibrations (mechanical oscillations) are applied along the longitudinal axis. In other words, it is more efficient to use the excitation of the axial vibration mode during the operation of the sonotrode, and the excitation of the unwanted transverse side modes is suppressed. This means that the axial working mode is more stable and the ultrasonic surgical instrument including the sonotrode according to the present invention is more efficient and easier to operate.

[0042] The shape of the proximal surface and the resulting overall shape of the cap makes it easier to transport the debris proximally, as the cap provides a kind of scoop. The scoop is arranged next to the sharp edge. This is particularly advantageous if the sonotrode is operated in a backward movement, which means a proximal movement.

[0043] The more proximally curved or oriented the proximal surface is, the greater the transport benefit.

[0044] The shape of the proximal surface and the resulting overall shape of the cap, in particular if it forms an overhang as disclosed below and / or if designed to support an oscillation mode of the cap as disclosed below, favors the presence of an oscillation mode in the cap that can be excited by vibrations along the longitudinal axis and coupled into the cap through the rod. In particular, it favors the presence of an oscillation mode with the largest amplitude at the radially outermost part of the cap, that is to say at the sharp edge. This means that the sharp edge can perform oscillations that are superimposed on the oscillations of the cap along the longitudinal axis caused by a transducer coupled to the sonotrode moving back and forth along the longitudinal axis.

[0045] Superimposing the oscillation of the longitudinal axis of the brim with the oscillation of the sharp edge may improve ablation of tissue by having an oscillation axis parallel to the longitudinal axis or by having a radially oriented component.

[0046] In an embodiment, the cap includes its centroid on the longitudinal axis by mirror symmetry about each portion (hereinafter referred to as a protruding portion) protruding more than the rod in the radial direction. In other words, the cap includes an imaginary mirror plane for each protruding portion, wherein the cap is mirror symmetric about the imaginary mirror plane.

[0047] The cap may have rotational symmetry of order n about the longitudinal axis, where n is an integer but not 1.

[0048] In an embodiment in which the above advantages are more pronounced, the surface of the cap arranged between the distal end of the rod and the sharp edge of the protruding portion is a concave surface that curves in the proximal direction to such an extent that the protruding portion includes an overhang.

[0049] In other words, the surface comprises a region which is arranged more laterally than an immediately adjacent region which is radially closer to the longitudinal axis than said region.

[0050] In an embodiment, said region arranged more proximally is the radially outermost region of the protruding portion.In particular, the sharp edge (or the proximal-most sharp edge as the case may be) is the proximal-most portion of the overhang.

[0051] Even in other words, the surface of the cap arranged between the distal end of the rod and the sharp edge of the protruding portion is a concave surface which is curved in the proximal direction to such an extent that the protruding portion comprises an undercut with respect to the radial direction.

[0052] In an embodiment, the cap is designed to comprise at least one oscillation mode which can be excited by mechanical oscillations, in particular coupled into the cap via the rod along the longitudinal axis. The at least one oscillation mode of the cap is generally complementary to the oscillation mode of the sonotrode along its longitudinal axis. However, the at least one oscillation mode of the cap can be excited by said oscillation mode of the sonotrode.

[0053] In other words, the cap is designed to ensure an oscillation mode of the cap superimposed with the oscillation mode of the sonotrode.

[0054] In ultrasonic surgical instruments, the oscillation mode of the sonotrode is caused by coupling the sonotrode to a transducer.

[0055] For example, the sonotrode may be designed according to at least one of the following design rules for the cap to include at least one oscillation mode that can be excited by mechanical vibrations coupled into the cap via the rod:

[0056] • The diameter of the rod in the region adjacent to the start of the cap is at most half the relevant diameter of the cap. In other words, the diameter d of the rod S The diameter d of the cap C The ratio between them is less than or equal to 0.5, d S / d C ≤0.5.

[0057] The relevant diameter is the diameter of the rod measured along a radial axis parallel to the radial axis.

[0058] Preferably, the ratio of the diameters is valid for at least one range of radial angles (directions). For example, the radial angle range may be greater than 45, 60, 90, 120, 135, 160 and 180 degrees.

[0059] The cap may comprise a plurality of radial angle ranges satisfying said ratio.

[0060] The ratio can be satisfied in any radial direction, which means that the radial angle range is 360 degrees.

[0061] In general, if the ratio is less than 0.5, for example less than 0.4, 1 / 3, 0.3, 0.25, 0.2 or 0.1, the likelihood of the cap having a significant oscillation mode increases. This also means that in principle it is possible to design a cap having a ratio greater than 0.5 but less than 1, d S / d C Cap of significant oscillation mode with a value < 1.

[0062] •The diameter of the largest possible circle that can be completely arranged within the cross-section of the rod is at most half the diameter of the smallest possible circle that can enclose the cap in a cross-section perpendicular to the longitudinal axis, wherein the cross-section of the rod is perpendicular to the longitudinal axis and is in the area of ​​the rod immediately adjacent to the beginning of the cap, wherein the cross-section of the cap is located at the position of the maximum lateral extension of the cap.

[0063] Again, if the ratio is less than 0.5, for example less than 0.4, 1 / 3, 0.3, 0.25, 0.2 or 0.1, the likelihood of the cap having a significant oscillation mode increases. This also means that in principle a cap having a significant oscillation mode with a ratio greater than 0.5 but less than 1 can be designed.

[0064] In an embodiment, the inscribed circle of the rod has a diameter in a cross section perpendicular to the longitudinal axis and in an area of ​​the rod adjacent to the beginning of the cap, which diameter is at most half the outer circle diameter of the cap in a cross section perpendicular to the longitudinal axis and at the position of the maximum lateral extension of the cap.

[0065] The ratio of the inscribed circle diameter to the outer circle diameter may be the ratio given above.

[0066] • Maximum longitudinal extension of the brim d L At most the maximum extension d of the part protruding in the radial direction beyond the rod R Half of L / d R ≤0.5.

[0067] In other words, the ratio between the maximum extension of the brim in the longitudinal direction and the maximum extension of the brim in the radial direction is less than or equal to 0.5, such as 0.4, 1 / 3, 0.3, 0.25, 0.2 or 0.1.

[0068] • The longitudinal extension of the cap depends on the distance from the longitudinal axis, wherein the longitudinal extension comprises a minimum value between the longitudinal axis and the sharp edge.

[0069] If the longitudinal extension of the cap comprises a minimum between the longitudinal axis and the sharp edge, the cap may comprise a radial portion comprising an oscillation mode superimposed on the oscillation mode of the sonotrode. This is particularly true if the radial portion is confined to a limited radial angular (direction) range.

[0070] The embodiment of a cap comprising segments as described below is an example of a cap which may comprise a radial portion in which segments having a smallest longitudinal extension are radially arranged and which is confined to a limited radial angular range.

[0071] In an embodiment, the cap comprises at least one region comprising a sharp edge and being connected to the body of the cap via a region of reduced mechanical stability of the cap.

[0072] The reduced mechanical stability may be such that the region of reduced mechanical stability may be elastically deformed by mechanical oscillations applied to the body of the cap. The mechanical oscillations of the body of the cap are typically part of the longitudinal oscillations of the sonotrode.

[0073] The region of reduced mechanical stability may include or be a resilient element.

[0074] In addition to the vibrator defined by the entire sonotrode, optionally in addition to the vibrator defined by the entire cap (if the oscillation mode can be ensured), and optionally in addition to the vibrator defined by the body of the cap (if the oscillation mode can be ensured), the area comprising sharp edges and connected to the body of the cap via the area of ​​the cap with reduced mechanical stability can be considered as a vibrator. In other words, the area can be considered as a separate vibrator.

[0075] In an embodiment, the sonotrode is designed for maximum vibration excitation of the cap.

[0076] This can be done by a sonotrode comprising a coupling for coupling to the transducer. The coupling may be a direct coupling to the transducer. However, the coupling is typically an indirect coupling via an intermediate sonotrode, meaning a sonotrode arranged between the transducer and the sonotrode according to the invention.

[0077] The coupling is usually arranged at the distal end of the sonotrode. The coupling may be of any kind suitable for a mechanically secure connection, which is capable of transmitting mechanical vibrations, in particular ultrasonic vibrations, from the transducer or the intermediate sonotrode to the sonotrode. For example, the coupling may comprise a thread, an element of a bayonet connection or an element of a clamping mechanism.

[0078] The sonotrode can have a coupling without being designed for maximum vibration excitation of the cap.

[0079] The ultrasonic welding electrode can be designed to maximally excite the cap by optimizing for a preset mechanical oscillation frequency (which means a preset operating frequency) and by making the distance d between the coupling and the cap substantially half the wavelength λ of the preset frequency or a multiple of half the wavelength of the preset frequency (which means d=n*λ / 2, where n is an integer).

[0080] The distance d may be the distance between the surface of the coupling element, in particular the sonotrode, which is designed to be in contact with the transducer, and the center of mass of the cap or the beginning of the cap.

[0081] In an embodiment, the cap comprises a convex surface.

[0082] The convex surface can be designed so that the overall shape of the cap is similar to a mushroom cap. This is particularly true for embodiments in which the cap includes a concave surface in any of the embodiments disclosed above or extends with a surface having an opening angle equal to or less than 90 degrees relative to the rod.

[0083] In an embodiment, the convex surface may be formed as a mushroom cap.

[0084] The convex surface may be configured to have a soft and / or smooth surface on the distal surface of the cap.

[0085] If the primary purpose of the sonotrode is to avoid damaging tissue close to the treatment site, the convexity or more generally the convex shape of the cap may be a feature thereof. In this case, other features of the sonotrode disclosed above, such as the location of the center of mass of the cap and the shape and / or orientation of the surface arranged between the distal end of the shaft and the sharp edge, may not be present.

[0086] In other words, the second aspect of the present invention also relates to a sonotrode for an ultrasonic surgical instrument, the sonotrode having a proximal head and a distal piece, the distal piece being equipped as a rod and a cap for ablating tissue, in particular bone, using mechanical vibrations. In other words, the distal piece comprises a rod and a cap for ablating tissue using mechanical vibrations. The sonotrode is configured to avoid damage to tissue close to the treatment site by the cap comprising a convex shape and at least one sharp edge, wherein the convex shape is configured to provide a soft and / or smooth surface on one side of the distal piece.

[0087] In other words, the soft and / or smooth surface is configured to prevent sonotrode ablation and / or any further detrimental effects in at least one direction.

[0088] In an embodiment, the sonotrode for avoiding tissue damage may include, alone or in combination, any of the features disclosed with respect to the sonotrode according to the main aspect of the invention. In particular, the cap may include a center of mass located on the longitudinal axis and a shape and / or orientation of a surface arranged between the distal end of the rod and the sharp edge that may be as disclosed above.

[0089] Although a soft and / or smooth surface is essential for a sonotrode to avoid damage, the sonotrode according to the main aspect of the invention may include a convex surface. However, the convex surface may include a structure for filing. The structure may be given by the surface roughness of the convex surface or by a plurality of sharp elements arranged on the convex surface.

[0090] The radially further protruding portion may be defined as follows: the rod extends radially relative to the longitudinal axis to a maximum distance from the longitudinal axis and the portion has a radial extension relative to the longitudinal axis that is greater than the maximum distance.

[0091] In an embodiment, the portion has a radial extension greater than the maximum distance over a range of radial angles. This means that the portion extends further than the maximum distance over the radial range. The radial direction along which the maximum distance is arranged may but need not be included in the radial range.

[0092] The radial angular range may be greater than 10 degrees, in particular greater than 20 degrees, for example greater than 45, 60, 90, 120, 135, 160 and 180 degrees. In particular, the radial angular range is such that the sonotrode is not blade-shaped or does not include a blade-shaped portion, since it comprises a cap with a portion having a radial extension greater than a maximum distance within said radial angular range.

[0093] The cap may comprise at least two, for example 2, 3 or 4, portions which protrude radially further than the stem,

[0094] This means that over a certain range of radial angles the radial extension is greater than the maximum distance, which means the maximum radial extension of the rod.

[0095] The part of the cap that extends radially farther than the rod can extend farther than the rod in any radial direction. In other words, the radial angle range in which the part extends radially farther than the rod can be 360 ​​degrees.

[0096] In any embodiment, the portion of the cap that extends radially further than the stem may include a contact site configured for contact with tissue during use of the sonotrode, and the contact site may include a sharp edge.

[0097] In any embodiment, the portion of the cap that extends radially further than the stem may include a sharp edge.

[0098] In an embodiment, the sharp edge is formed by at least one of:

[0099] • The cap comprises a distally facing convex surface and the sharp edge is formed by the transition of the convex surface to a concave surface or a surface with an opening angle equal to or less than 90 degrees relative to the stem.

[0100] • A transition from a first surface that is flat, concave or convex to a second surface that is flat, concave or convex, wherein the orientations of the first and second surfaces are different.

[0101] The flat surface or, as the case may be, one of the flat surfaces may be a surface extending at an opening angle equal to or less than 90 degrees relative to the rod, in particular a radial end thereof.

[0102] The concave surface or, as the case may be, one of the concave surfaces may be a concave surface arranged between the distal end of the rod and the sharp edge, in particular a radial end thereof.

[0103] The convex surface or, as the case may be, one of the convex surfaces may be the distally facing convex surface, in particular a radial end thereof.

[0104] • One or more protrusions arranged on a convex, concave surface between the distal end of the rod and the sharp edge, or on a surface extending at an opening angle equal to or less than 90 degrees relative to the rod, in particular one or more protrusions arranged at the radial ends of said surface.

[0105] For example, by including a distally facing convex surface and a proximally facing concave surface, the cap can be mushroom-shaped.Then, the sharp edge can be formed by the transition from the distally facing convex surface to the proximally facing concave surface.

[0106] Independently of the specific implementation of the cap, the sharp edge (or sharp edges, as the case may be) may be arranged on a portion of the cap that protrudes radially further than the rod.

[0107] In an embodiment and independently of the specific implementation of the cap, the sharp edge may be arranged at the radially outermost portion of the cap, such as the radially outermost portion of a mushroom-shaped cap. In other words, the edge is arranged on or formed by a portion of the cap that is at a greater distance from the longitudinal axis than any other portion of the cap, wherein the distance to the longitudinal axis is measured in a radial direction (radial with respect to the longitudinal axis).

[0108] Regardless of the specific implementation of the cap, the sharp edge can be rotationally symmetric about a rotation around the longitudinal axis. For example, the sharp edge can have a circular shape centered on the longitudinal axis.

[0109] In an embodiment and independently of the specific realization of the cap, the sharp edge may be formed by a plurality (that means at least two) of edge pieces.

[0110] The edge piece can be separated by a recess, in particular by a recess extending radially toward the longitudinal axis.

[0111] The edge pieces may be arranged in such a way that they are rotationally symmetric with respect to a rotation about the longitudinal axis. This means that a rotation of the cap by 360° / n (where n is an integer) about the longitudinal axis is a symmetric transformation of the cap. The number of edge pieces may be n. However, embodiments may be envisaged in which the number of edge pieces is different from n, for example by including different kinds of edge pieces and by arranging the different edge pieces in a set order.

[0112] Alternatively, the sharp edge or the edge element can be arranged in such a way that the sharp edge is not rotationally symmetrical with respect to the longitudinal axis.

[0113] However, the overall shape of the cap must be chosen in such a way that the requirement that the center of mass of the cap lies on the longitudinal axis is met, at least as far as it relates to the sonotrode according to the main aspect of the invention. This can be achieved by selecting the number, type and arrangement of the edges accordingly or by using balancing weights.

[0114] In an embodiment, the sharp edge or edge piece may be arranged only in one segment. This means that the sharp edge or edge piece is arranged only in a limited radial range (limited radial angle range). For example, the arrangement of the sharp edge or edge piece may be limited to the area where the sonotrode is configured for ablation during use of the sonotrode.

[0115] Again, the overall shape of the cap must be chosen in such a way that the requirement that the centre of mass of the cap lies on the longitudinal axis is met, at least as far as it relates to the sonotrode according to the main aspect of the invention.

[0116] The edges or edge pieces may be arranged to limit the contact points.

[0117] The edges or edge pieces may be arranged in an application specific manner. For example, the edges or edge pieces may be arranged to treat a specific bone, a specific part of a bone or to treat or create a specific incision in a bone. Additionally or alternatively, the edges or edge pieces may be arranged to localize a treatment area, which means improving the controllability of the treatment area, for example by limiting the contact site and / or by limiting sharp edges within the contact site.

[0118] For example, the edge or edge member may be arranged to treat a specific bone, a specific portion of a bone, or a specific cut of a bone or a specific cut in a bone without rotating the sonotrode and / or ultrasonic surgical instrument about its longitudinal axis.

[0119] For example, the edge or edge piece can be arranged in a radial angle range of less than 90 degrees for treatment along a substantially flat bone surface, for establishing a well-defined recess with a small width, or for cutting a small bone, etc. The radial angle range can be between 90 and 180 degrees for treatment along a bone surface that is curved from 1 to 90 degrees, wherein if the curve is close to 1 degree, the radial angle range is preferably close to 90 degrees, and if the curve is close to 90 degrees, the radial angle range is preferably close to 180 degrees. In addition, for example, an angle range between 90 and 180 degrees can be used to establish a recess of greater width (compared to a bone that can be cut with a smaller range of radial angles) or to cut a larger (particularly wider) bone (compared to the width established by a smaller range of radial angles). Thus, for example, for a bone surface that is curved more than 90 degrees, an even larger recess or for cutting an even larger (wider) bone, the edge or edge piece can be arranged in a radial angle range greater than 180 degrees. In other words, the radial angle range can be adapted, for example, to the shape of the bone to be treated, the form of the recess to be established and / or the size of the bone to be cut.

[0120] The edge or edge element may be arranged in segments, which means in at least two ranges of radial angles, wherein the two ranges are separated by a region comprising no edge or edge element.

[0121] For example, the segments may be separated by recesses, in particular recesses extending radially towards the longitudinal axis and / or by segments that are not configured for ablating tissue.

[0122] The circumferential surface of the cap can be adapted to the desired position of the sharp edge or edge piece.

[0123] The circumferential surface may be formed by portions having a radial extension greater than the maximum distance and portions having a radial extension less than the maximum distance.The circumferential surface may have the same symmetrical properties as a sharp edge or edge piece.

[0124] In an embodiment, the sonotrode comprises at least two sharp edges according to any of the embodiments of the sharp edges described above, wherein the at least two sharp edges are offset in a proximal to distal direction. In other words, the at least two sharp edges are offset in a longitudinal direction of the sonotrode.

[0125] For example, at least two sharp edges can be arranged in such a way that the sharp edges are arranged mirror-symmetrically with respect to a mirror plane having a normal parallel to the longitudinal axis.

[0126] Such an arrangement of at least two sharp edges is particularly advantageous if the cap comprises at least one oscillation mode and / or if the cap comprises at least one region which can be excited by the longitudinal oscillations of the rod and which has a maximum amplitude in the region of the at least two sharp edges, which region comprises the at least two sharp edges and is connected to the body of the cap via a region of reduced mechanical stability of the cap, such that the region comprising the sharp edges comprises its own ("autonomous") oscillation behavior. In these cases, the cap (and, as the case may be, the region comprising at least two sharp edges) can comprise an oscillation mode which can be excited by the longitudinal oscillations of the rod, wherein the at least two sharp edges oscillate predominantly in the proximal to distal direction.

[0127] At least two sharp edges may be offset in the radial direction (radially relative to the longitudinal axis).

[0128] For example, the circumferential surface of the cap may include a surface having a surface normal substantially coinciding with a radial direction (radial direction relative to the longitudinal axis). The surface may be part of an imaginary surface around the longitudinal axis, wherein each point on the imaginary surface has the same distance from the longitudinal axis. The surface may be a surface around the longitudinal axis, wherein each point on the surface has the same distance from the longitudinal axis.

[0129] Then, the transition from the surface to the surface of the cap having a surface normal (wherein at least one component points distally) can form a first sharp edge, and the transition from the surface to the surface of the cap having a surface normal (wherein at least one component points proximally) can form a second sharp edge.

[0130] Alternatively or additionally, the cap may comprise at least one step having a radial distance from the longitudinal axis greater or less than a radial distance of an adjacent surface of the cap. The adjacent surface of the cap may for example be formed by a convex surface, a flat surface, a concave surface or other step.

[0131] For example, the cap includes a first step, at least one further step, and a transition from the proximal-most step to a surface of the cap oriented proximally, wherein the first step increases the distance of the circumferential surface of the cap from the longitudinal axis relative to the convex surface, and the further step increases the said distance of the circumferential surface of the cap relative to the first step.

[0132] In any of the embodiments above, a sonotrode having a cap including a circumferential surface having a surface normal that is substantially consistent with a radial direction and is serrated is another example of a sonotrode including at least two sharp edges.

[0133] It goes without saying that the various embodiments of the sharp edges can be combined in any manner to design a sonotrode having at least two sharp edges.

[0134] An advantage of a sonotrode having at least two sharp edges is that it ablates when the sonotrode is moved in a distal direction during use of the sonotrode and when the sonotrode is moved in a proximal direction during use of the sonotrode if at least one sharp edge is configured such that it ablates when the sonotrode is moved in a distal direction during use and at least one sharp edge is configured such that it ablates when the sonotrode is moved in a proximal direction.

[0135] Therefore, the present invention relates to a sonotrode according to any of the disclosed embodiments, and further having at least two sharp edges which can be implemented according to any of the embodiments disclosed above, wherein at least one sharp edge is configured such that it ablates when the sonotrode is moved in a distal direction during use, and at least one sharp edge is configured such that it ablates when the sonotrode is moved in a proximal direction.

[0136] Furthermore, the multiple sharp edges expand the application possibilities of the sonotrode, in particular when the tissue to be treated (eg bone) is curved, as is the case with vertebrae, hip bones, shoulder bones and many other bones or bone regions.

[0137] The inventors have observed that the removal of debris or (chips of the treated hard or soft tissue) can alternatively be facilitated by a sonotrode that performs a nodding motion. The sonotrode then works in the manner of a shovel that removes the debris. Therefore, in an embodiment, the sonotrode has a design that increases the main x-amplitude of the vibrations (which means increasing the main vibrations along the longitudinal axis), a significant z-amplitude (which means vibrations in the radial direction). This further results in the tissue being ablated not only by a pushing motion but also by a motion substantially perpendicular to the pushing motion. This further improves the ablation performance and allows for improved ablation of tissue, in particular ablation of bone, such as cortical bone.

[0138] In an embodiment, the nodding motion is a nodding motion of a radial portion, which comprises an oscillation mode superimposed with the oscillation mode of the sonotrode described above. In other words, the nodding action is a nodding motion of at least a sub-portion of the cap.

[0139] The following statements or embodiments relate to all aspects and embodiments described herein.

[0140] In an embodiment, the diameter of the rod may decrease towards the distal direction. In other words, the rod may include at least one region that tapers towards the distal direction.

[0141] It has been observed that the tapered region can have an amplitude effect, which means an increase in the amplitude and intensity of the mechanical vibrations.

[0142] The sonotrode may also include a tapered region for transitioning the coupling member to the shaft.

[0143] In an embodiment, the sonotrode comprises a sleeve which is arranged or configured to be arranged around the rod such that the rod is spaced from the outside of the sleeve and the sharp edge is exposed at least in a lateral direction.

[0144] In particular, the sleeve may be designed to laterally surround the rod, in particular the entire rod except for a portion adjacent to the cap.

[0145] In an embodiment, the sonotrode comprises means for providing fluid to the treatment site and / or for removing fluid and / or debris from the treatment site.

[0146] The fluid may be a coolant and / or a flushing fluid.

[0147] The means for providing may be a channel arranged in the sonotrode.

[0148] The sonotrode in any embodiment according to the present invention may have the following dimensions, for example:

[0149] •The diameter of the cap can be between 2 mm and 15 mm, for example for endoscopic applications, between 2 mm and 6 mm, between 3 mm and 5 mm or between 3 mm and 4 mm, for example for "open" applications, between 4 mm and 10 mm or between 5 mm and 8 mm.

[0150] • The diameter of the rod can be between 1 mm and 10 mm, for example between 1 mm and 6 mm directly, between 1 mm and 3 mm or between 1 mm and 2 mm for endoscopic applications, and for example between 2 mm and 8 mm or between 3 mm and 6 mm for "open" applications.

[0151] • The portion protruding radially further than the shaft may protrude at least 0.5 mm further. For example, it may protrude further by 0.5 mm to 4 mm, such as 0.5 mm to 2 mm or 0.5 mm to 1 mm (endoscopic application) or 1 mm to 2 mm ("open" application).

[0152] In particular and independently of the application, the dimensions of the rod are selected such that the portion which protrudes radially further than the rod protrudes at least 0.5 mm further.

[0153] •The longitudinal extension of the cap may be between 1 mm and 5 mm.

[0154] • The longitudinal extension of the rod and of the entire sonotrode can be chosen to meet the requirements for maximum vibration excitation of the cap disclosed above.

[0155] The exact dimensions are application specific, as indicated by the exemplary numbers given for "endoscopic" and "open" applications.

[0156] The inventors have found that there are some surprising advantages of ultrasonic welding electrodes manufactured by additive manufacturing methods, in particular using sintering (such as selective laser sintering). The ultrasonic surgical instrument according to the present invention is usually equipped with a pipeline (channel) through which a flushing liquid (such as water) can be supplied to the operating area. The surface structure produced using the above-mentioned manufacturing method improves the cooling efficiency of this liquid. One explanation may be that the surface structure provides and maintains an appropriate liquid film on the surface of the ultrasonic welding electrode. It seems that a possible effect is that the pockets produced by the sintering process are not open to the sides to provide a static pressure pad. In addition, only by using additive manufacturing methods can it be possible to produce some of the advantageous features of the ultrasonic welding electrode described here, such as raised structures that optionally have only a minimum distance from each other. In addition, the use of additive manufacturing can adapt the transition between different elements of the ultrasonic welding electrode.

[0157] One embodiment of the present invention relates to a sonotrode, for example to a sonotrode according to any of the embodiments described herein, wherein the surface of the sonotrode, in particular the surface of the sonotrode arranged to come into contact with tissue during operation of the sonotrode, for example the surface forming a sharp edge and / or the surface facing distally, for example the convex surface, has a convex microstructure. The microstructure is curved or rounded outward like the outside of a sphere or a circle. Another embodiment of the present invention relates to a sonotrode, for example to a sonotrode according to any of the embodiments described herein, wherein the surface of the sonotrode, in particular the surface of the sonotrode arranged to come into contact with tissue during operation of the sonotrode, for example the surface forming a sharp edge and / or the surface facing distally, for example the convex surface, has an average roughness R between 1 micrometer and 40 micrometers, preferably between 5 micrometers and 15 micrometers or 20 micrometers. a . Therefore, surface roughness as a component of surface texture is quantified by the deviation of the normal vector direction of the real surface from its ideal form. The arithmetic mean roughness R a It is the arithmetic mean of the filtered roughness profile determined by the deviations around the centerline within the evaluation length and the most widely used one-dimensional roughness parameter.

[0158] In general, it has been shown that it is advantageous if the distance between the highest point of any convex microstructure of the sonotrode and the sonotrode surface at the location of the convex microstructure is smaller than the amplitude. Thus, the highest point of a convex microstructure is a point defining a hemisphere, where the radius coincides with an imaginary line of the sonotrode surface at the location of the microstructure. The average distance between two corresponding points on a convex structure, in particular the highest point of each convex structure, can be from 20 micrometers to 100 micrometers, preferably from 40 micrometers to 80 micrometers.

[0159] Due to the surface roughness produced by the sintering process, there is point contact between the cap, in particular the contact site, and the tissue. Therefore, a higher energy density occurs. However, the convex surface produced by the particle size distribution is more stable than a rough structure produced, for example, by sandblasting.

[0160] Thus, one embodiment of the invention relates to a method of manufacturing a sonotrode as defined herein, wherein the sonotrode or a portion thereof, in particular the cap or a portion thereof, is manufactured by using an additive manufacturing method. Direct Metal Laser Sintering (DMLS) is an additive manufacturing process suitable for producing a sonotrode according to the invention. Thereby, the sonotrode, in particular the surface of the sonotrode arranged to come into contact with tissue during operation of the sonotrode (e.g. the surface forming the sharp edge and / or the surface facing distally, e.g. the convex surface), is structured using a laser to selectively sinter (heat and fuse) powdered metal material into layers. A heat treatment step may subsequently be performed. Preferably, the surface resulting from additive manufacturing is not smooth (flattened or polished). The average particle size of the powder used may be between 40 microns and 80 microns.

[0161] An alternative method suitable for manufacturing a sonotrode is shot blasting or peening, in particular the surface of the sonotrode arranged for contact with tissue during operation of the sonotrode, such as the surface forming a sharp edge and / or the surface facing distally, such as the convex surface. Sandblasting is less suitable. The surface structure produced by the metal grain sintering process cannot be fully described by parameters such as roughness and grain size. However, this special surface structure has proven to be advantageous. Therefore, the present invention relates to a sonotrode according to the present invention, wherein the sonotrode or at least the cap or the contact part is manufactured using an additive manufacturing method, such as direct metal laser sintering. In particular, the present invention relates to a sonotrode for an ultrasonic surgical instrument, in particular a sonotrode according to any embodiment described herein, wherein the sonotrode, in particular the surface of the sonotrode arranged for contact with tissue during operation of the sonotrode, such as the surface forming a sharp edge and / or the surface facing distally, such as the convex surface, is produced using an additive manufacturing method such as direct metal laser sintering. Other embodiments relate to a sonotrode equipped or designed as described herein, which is manufactured using an additive manufacturing method such as direct metal laser sintering.

[0162] For example, the surface of the sonotrode or the surface of the cap or the surface of the contact point may have an average roughness Ra of between 5 μm and 40 μm.

[0163] In the case where the roughness is only used to minimize friction, a roughness between 1 micron and 20 microns, in particular between 1 micron and 15 microns, is sufficient. If the sonotrode according to the invention is used as a file, the roughness is preferably between 10 microns and 100 microns. The purpose of using the sonotrode as a file is to smooth tissue, such as bone, especially the edges produced by cutting. It is mainly very useful because if rough bone areas are not smoothed using a file, they can damage the surrounding tissue. However, in terms of its filing and abrasive properties, roughness can even be more invasive. For example, the roughness can be up to 500 microns, for example between 100 microns and 250 microns, between 100 microns and 150 microns or between 100 microns and 120 microns. The surface can include well-defined structures of this size instead of a corresponding surface roughness.

[0164] The present invention also relates to an ultrasonic surgical instrument for ablating tissue, comprising a handpiece comprising an ultrasonic transducer and a sonotrode according to any embodiment defined herein mechanically coupled to the transducer. The term "ultrasonic surgical instrument" as used herein refers to a surgical instrument having an ultrasonic transducer. Such an ultrasonic surgical instrument of the present invention comprises a sonotrode as described herein connected to an ultrasonic transducer. The ultrasonic transducer may comprise a piezoelectric element, by means of which a high frequency AC voltage is converted into a corresponding mechanical oscillation. By way of example, the frequency of the oscillation may be between 15 kilohertz (kHz) and 40 kHz.

[0165] Preferably, the housing of the ultrasonic transducer or ultrasonic surgical instrument of the present invention and the ultrasonic welding electrode are coupled to each other (via a coupling piece), wherein the ultrasonic welding electrode is designed to transfer the oscillation energy from its proximal end to the distal end piece of the ultrasonic welding electrode, i.e., to the cap, as fully as possible.

[0166] Preferably, the material of the sonotrode according to any embodiment of the present invention is a metallic material, such as, for example, stainless steel or titanium. The sonotrode or at least its cap or at least its contact portion may be coated with titanium nitride (TiN). Therefore, the present invention relates to a sonotrode, such as a sonotrode according to any embodiment described herein for an ultrasonic surgical instrument, having a shaft and a cap for ablating tissue using mechanical vibrations, wherein the sonotrode or at least the cap or the contact portion of the sonotrode is coated with titanium nitride and is preferably manufactured using an additive manufacturing method such as direct metal laser sintering.

[0167] It has been shown that spherical microstructures on the sonotrode or cap or surface contacting tissue may be deformed due to the forces acting during the process of cutting and ablating tissue. Therefore, it is preferred to coat the sonotrode or cap or contacting tissue to harden the surface. Titanium nitride has an ideal combination of hardness, toughness, adhesion and inertness and will not blister, flake or crumble when ablating tissue tip.

[0168] Another advantage is that the heat distribution is optimized along the length of the surface produced by the titanium nitride coating. In this way, hot spots are avoided, and the heat distribution or heat spreading along the length of the surgical cutting instrument prohibits heat concentration at the contact points, especially at the sharp edges, which would occur without a coating or with a coating only at the contact points.

[0169] Titanium nitride coatings can be applied via environmentally safe physical vapor deposition (PVD) vacuum systems. Some processes use low temperature arc vapor deposition to deposit titanium nitride coatings, but they can also be applied via high temperature sputtering or other well-known coating processes (electron beam heating or chemical vapor deposition (CVD)). Typically, pure titanium sublimates and reacts with nitrogen in a high energy vacuum environment. Titanium nitride films can also be produced on titanium workpieces by reactive growth (e.g., annealing) in a nitrogen atmosphere.

[0170] The titanium nitride coating is preferably applied as a thin coating of less than 5 microns, more preferably less than 3 microns. The thin titanium nitride coating provides a hard outer surface for the insert with a low coefficient of friction.

[0171] Preferably, the connection between the sonotrode and the oscillation generator is releasable and the sonotrode is disposable.

[0172] The ultrasonic surgical instrument according to the invention is, for example, a handheld device, wherein its handle part houses an oscillation generator which is supplied with the necessary energy by means of a battery or by means of a corresponding cable connecting the handpiece to a control and supply unit. The preferred frequency of the oscillation is in the ultrasonic range, preferably in the range of 15 to 40 kHz or between 20 and 30 kHz, and has an energy sufficient to reach an amplitude in the micrometer range at the distal end of the rod, which is between 20 micrometers and 120 micrometers, or preferably between 60 micrometers and 100 micrometers.

[0173] Methods for improving the controllability and / or extension of the treatment area have been disclosed above with respect to sonotrodes, such as a sharp edge or multiple sharp edges or edge pieces arranged only in one or more segments. Methods for improving efficiency and avoiding the excitation of unwanted oscillations have also been disclosed above.

[0174] In an embodiment, an ultrasonic surgical instrument may include a sleeve mounted or mountable to a handpiece and designed to laterally surround the shaft and leave the sharp edge exposed in at least a lateral direction when the sleeve is mounted to the handpiece and the sonotrode is connected to the ultrasonic transducer.

[0175] In other words, in addition to or as an alternative to any embodiment of the cap configured to improve controllability and / or extension of the treatment area, the sleeve defines an interior of the sleeve and an opening between the interior and exterior of the sleeve. In this embodiment, the sleeve is mounted or mountable to the handle portion and is designed such that the shaft and the cap according to any embodiment are shielded from the exterior except for a restricted portion of the cap configured to ablate tissue when the sleeve is mounted to the handle portion and the sonotrode is connected to the ultrasonic transducer.

[0176] The sleeve, in particular its opening or its openings, may be arranged in an application-specific manner. For example, one or more openings may be arranged to treat a specific bone, a specific part of a bone, or to treat or create a specific incision in a bone or in a bone. Additionally or alternatively, one or more openings may be arranged to localize one or more treatment areas, which means improving the controllability of the treatment area, for example by limiting the contact site and / or by limiting sharp edges within the contact site.

[0177] In an embodiment, the sleeve is mounted or mountable to the handle part in such a way that it can be rotated about the longitudinal axis of the sonotrode without rotating the ultrasonic surgical instrument, in particular without rotating the handle part.

[0178] Additionally, the ultrasonic surgical instrument may include an orientation indicator configured to indicate an orientation of the opening relative to a set direction.

[0179] The sleeve in any of the disclosed embodiments not only protects the tissue from unwanted treatment. It also reduces the impact of the tissue on the sonotrode. In particular, it prevents the attenuation of mechanical vibrations due to the contact of the sonotrode (e.g., rod) with the tissue. In addition, it can reduce lateral forces acting on the sonotrode, such as caused by soft tissue.

[0180] The sleeve is particularly suitable for long sonotrodes, for example because its lateral extension is designed to maximally excite the vibration of the cap, which means that the lateral extension d is in the range d=n*λ / 2, where λ is the wavelength of the sonotrode operating frequency and n is an integer.

[0181] Furthermore, the sleeve may ensure the supply of coolant and / or irrigation fluid to the treatment site and / or the removal of debris from the treatment site, such as by suction.

[0182] This embodiment of the ultrasonic surgical instrument is particularly advantageous in combination with a sonotrode configured to treat a larger treatment area than given by the opening. For example, the sonotrode, more precisely its cap, may have at least one sharp edge that is continuous around the longitudinal axis or that is continuous around the longitudinal axis except for some recesses. In other words, the sharp edge may substantially form a circle around the longitudinal axis, wherein the center of the circle is on the longitudinal axis.

[0183] Embodiments with a rotatable sleeve are advantageous for treating complex tissue shapes, such as complex bone shapes and / or difficult-to-access treatment areas. Thus, the treatment area can be adjusted with minimal manipulation of the ultrasonic surgical instrument, the treatment area is always clearly defined, and the sleeve protects tissue that does not need to be treated.

[0184] Another aspect of the invention relates to a method of ablating tissue. Thus, the invention relates to a method of using a sonotrode, in particular using a sonotrode according to the invention in any of the disclosed embodiments, the method comprising the steps of providing a sonotrode at an ultrasonic surgical instrument according to any of the disclosed embodiments and oscillating the cap to ablate (file, file, grind, cut, etc.) tissue.

[0185] The method may also include any steps directly related to the characteristics of the sonotrode, such as at least one of the following:

[0186] •Operate ultrasonic surgical instruments in push and / or pull modes;

[0187] •Operating the ultrasonic surgical instrument in a manner suitable for ablating hard tissue, particularly bone tissue, such as by operating the ultrasonic surgical instrument so that the amplitude of the sharp edge is a maximum of 100 microns, or operating the ultrasonic surgical instrument in a manner suitable for ablating soft tissue, such as by operating the ultrasonic surgical instrument so that the amplitude of the sharp edge is 150 microns or greater.

[0188] •Rotate the sleeve of the ultrasonic surgical instrument without rotating the sonotrode.

[0189] As mentioned at the outset, the improvement of the sonotrode makes it possible to use the sonotrode improved according to the invention not only for open surgery but also for minimally invasive surgery (MIS).

[0190] In an embodiment, a sonotrode for MIS and thus an ultrasonic surgical instrument comprises:

[0191] A handle extending along the longitudinal axis and a cap configured to perform an ablation operation on tissue using mechanical oscillation, wherein the cap includes at least one portion that protrudes radially further than the shaft, wherein the at least one portion includes at least one sharp edge. The cap also includes a surface disposed between the distal end of the shaft and the sharp edge of the portion, and the surface is concave and / or extends at an opening angle equal to or less than 90 degrees relative to the shaft. The cap also includes its center of mass on the longitudinal axis.

[0192] The cap, the rod, the portion protruding radially further than the rod, the sharp edge, and the surface arranged between the distal end of the rod and the sharp edge may be according to any disclosed embodiment.

[0193] With any of the disclosed embodiments, the center of mass of the cap may be on the longitudinal axis.

[0194] • A rod of length d, d being substantially half the wavelength of a preset frequency or a multiple of half the wavelength of a preset frequency, d=n*λ / 2, where n is an integer.

[0195] The length of the rod can be considered as the distance between the coupling and the cap of a straight or straightened sonotrode. The length of the rod can deviate to some extent from n*λ / 2, for example if the sonotrode is designed for a maximum amplitude of longitudinal oscillations within the cap (e.g. at its center of mass, rather than at its proximal end). Furthermore, the implementation of the coupling can cause the rod to deviate to some extent from n*λ / 2.

[0196] In many embodiments of a sonotrode configured for MIS, the rod has a constant diameter.

[0197] • The sleeve is arranged or configured to be arranged around the rod in such a way that the rod is spaced apart from the exterior of the sleeve. The sleeve may be according to any embodiment disclosed above.

[0198] As mentioned at the outset, the sonotrode according to the invention can be configured for ablating hard tissue or soft tissue.

[0199] It has been observed that sharp edge amplitudes below 150 microns, particularly below 100 microns, for example between 40 microns and 80 microns, are most effective for ablating hard tissue, particularly bone tissue.

[0200] The relevant amplitude is in particular the amplitude along an axis parallel to the longitudinal axis.

[0201] Amplitude is usually measured as the distance between two turning points.

[0202] In an embodiment, the sonotrode is configured to have a sharp edge amplitude of a maximum of 100 micrometers during use of the sonotrode.

[0203] On the other hand, it has been observed that the amplitude of the sharp edge is greater than 100 microns, in particular greater than 150 microns or 200 microns, for example between 150 microns and 300 microns, is most effective for ablating soft tissue. One reason why the amplitude of the sharp edge in this range is effective for ablating soft tissue is that the soft tissue can no longer be deformed in a sufficient manner without being ablated.

[0204] In an embodiment, the sonotrode is configured to have a sharp edge amplitude of 150 microns or greater during use of the sonotrode.

[0205] However, sonotrodes used in ultrasonic surgical instrument materials are typically made of materials and designs where the phonons cannot achieve amplitudes greater than 100 microns, which simply means the material stretches.

[0206] Thus, in an embodiment, the sonotrode for ablating soft tissue comprises means for increasing the amplitude of the sharp edge, in particular any of the means discussed above.

[0207] In particular, such a sonotrode may comprise at least one of the following: a rod having a tapered region ("amplitude effect") as disclosed above, an overall shape of the cap that favors the presence of an oscillation mode of the cap in any of the above-described embodiments (in particular an oscillation mode having a maximum amplitude at the radially outermost portion of the cap), and a region of reduced mechanical stability of the cap, in particular such that the region comprising the sharp edge comprises a "own" ("autonomous") oscillation mode ("independent vibrator").

[0208] In contrast, sonotrodes used for ablating hard tissue, especially bone tissue, do not require a device for increasing the amplitude of the sharp edge, since the amplitude that the phonons can reach is sufficient to ablate hard tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0209] Exemplary embodiments of the apparatus and method according to the present invention are described in more detail with reference to the accompanying drawings.

[0210] Figure 1 A distal portion of an ultrasonic surgical instrument for ablating tissue is shown including a transducer within a housing and having a sonotrode at a forward end of the housing.

[0211] Figure 2 and Figure 3 A schematic diagram of a first exemplary embodiment of a sonotrode according to the invention is shown.

[0212] Figure 4 Shown according to Figure 2 and Figure 3 Detailed view of the cap of the sonotrode.

[0213] Figure 5 A schematic diagram of another exemplary embodiment of a sonotrode according to the present invention is shown.

[0214] Figure 6 Shown according to Figure 5 Detailed view of the cap of the sonotrode.

[0215] Figure 7 Shows Figure 5 and Figure 6 Schematic diagram of a variation of an exemplary embodiment of the present invention.

[0216] Figure 8 Shown according to Figure 7 Detailed view of the cap of the sonotrode.

[0217] Fig. 9 A schematic diagram shows a further exemplary embodiment of a sonotrode according to the present invention.

[0218] Fig.10 Shown according to Fig. 9 Schematic diagram of a variation of an exemplary embodiment of the present invention.

[0219] Fig.11 Shown according to Fig.10 Detailed view of the cap of the sonotrode.

[0220] Figure 12a to Figure 12b Schematic diagram showing a sonotrode partially shielded by a sleeve ( Fig.12a ) and its cross-sectional view ( Figure 12b ).

[0221] Figures 13 to 16 A schematic diagram of a further exemplary embodiment of a cap is shown.

[0222] Figure 17 to Figure 18 A schematic diagram of an exemplary embodiment of a sonotrode including cooling and / or means for facilitating removal of debris from a treatment site is shown.

[0223] Fig.19 A schematic diagram of an exemplary embodiment of a sonotrode according to the second aspect of the invention is shown.

[0224] Fig. 20 Shown according to Fig.19 Detailed view of the cap of the sonotrode. DETAILED DESCRIPTION

[0225] In all drawings, the same reference numerals denote the same elements or similar elements having the same function.

[0226] Figure 1 The distal part of an ultrasonic surgical instrument for ablating tissue is shown. The instrument comprises a transducer 3 , such as a piezoelectric stack, located inside a housing 2 , and a sonotrode 1 arranged at the front end of the housing 2 .

[0227] Figure 2 and Figure 3 Two different views of a first exemplary embodiment of a sonotrode 1 according to a main aspect of the invention are shown.

[0228] The sonotrode 1 has a proximal end 4 with a coupling 13 (thread 13 in the embodiment shown), a rod 21 and a cap 22. The cap 22 comprises a convex shape 24 and at least one sharp edge 23. The cap is designed and adapted to ablate (scrape, file) unwanted bone structures such as osteophyte tissue, for example. The sharp edge can be used to scrape or file away tissue, while the surface (convex, arcuate surface) of the convex shape 24 is smooth and formed in the embodiment shown to protect the tissue.

[0229] Figure 4 Shows Figure 4 and Figure 5 A detailed view of the cap 22 is shown in FIG.

[0230] The sonotrode 1 extends along a longitudinal axis 15 .

[0231] exist Figure 2 In the embodiment shown, a flattened (tapered) region 12 of the proximal end 4 forms the transition between the proximal end 4 and the shaft 21 .

[0232] The flattened (tapered) area 12 reduces the diameter of the distal end of the proximal end 4 of the sonotrode to the preferred diameter of the shaft 21. The diameter of the proximal end 4 may be determined by the coupling 13 and / or by the need to provide a coupling surface 40 of the sonotrode 1.

[0233] A further flattened (tapered) region 12 is arranged within the rod 21. A flattened (tapered) region 12 arranged in this way can act as a "horn", which means that it can increase the amplitude and intensity of the mechanical vibrations far from the flattened region 12 compared to the amplitude and intensity of the mechanical vibrations near the flattened region 12.

[0234] The cap 22 of the sonotrode comprises a portion 16 which protrudes radially relative to the longitudinal axis 15 further than the shaft 21 .

[0235] More precisely, the cap 22 comprises a portion 16 which is arranged further from the longitudinal axis 15 in a radial direction relative to the longitudinal axis 15 than a maximum extension 14 of the rod 21 in a radial direction relative to the longitudinal axis 15. The portion 16 can be defined by an extent of the longitudinal axis 15, wherein the cap 22 extends more in a radial direction than the maximum extension 14 of the rod 21, and by a radial angular extent 19, wherein the portion 16 extends more in a radial direction than the maximum extension 14 of the rod 21, said radial angular extent 19 being determined at at least one position within said extent of the longitudinal axis 15.

[0236] The portion 16 protruding radially further than the rod comprises a sharp edge 23 .

[0237] Figures 2 to 4 The cap 22 of the illustrated embodiment is rotationally symmetrical about the longitudinal axis. This ensures that the center of mass 43 of the cap 22 is on the longitudinal axis 15.

[0238] In the embodiment shown, the cap is formed as a mushroom cap having a distally facing convex surface 24 and a proximally facing concave surface 26. The portion 16 protruding radially further than the stem 21 covers a radial angular range 19 of 360 degrees.

[0239] The concave surface 26 is bent toward the proximal side at its radially outermost region, thereby forming an overhang 35 .

[0240] The sharp edge 23 of the cap 22 is formed by the transition between a distally facing convex surface 24 and a proximally facing concave surface 26 .

[0241] Due to the orientation of the sharp edge 23 formed in this way, the sonotrode 1 works most effectively when moving proximally ("pull mode"). In addition, the possibility of damaging tissue that should not be injured is reduced, because the sharp edge 23 is located distal to the tissue to be ablated and only tissue arranged between the sharp edge 23 and a portion of the sonotrode that protrudes radially more than the sharp edge 23 is ablated.

[0242] Furthermore, any force vectors generated by the sharp edge 23 during operation of the sonotrode 1 are directed towards the tissue to be ablated. The design of the sonotrode 1 also makes the sharp edge 23 possible and improves the removal of debris from the treatment site.

[0243] The convex surface 24 may be soft and / or smooth to avoid damaging tissue that does not require treatment, for example during operation of the sonotrode or during insertion of the sonotrode.

[0244] Alternatively, the convex surface 24 may include structures suitable for filing tissue. For example, the convex surface 24 may be covered with structures having a height between 100 microns and 120 microns. In other words, Figures 2 to 4 The cap of the sonotrode 1 shown in FIG. 4 can be configured to also ablate, eg grind, when moved distally (“push mode”).

[0245] according to Figures 2 to 4 The cap 22 is designed to ensure an autonomous oscillation mode that can be excited by the longitudinal mechanical vibrations coupled into the cap via the rod 21. In addition to the overall shape of the cap 22 being conducive to ensuring such an oscillation mode, the diameter d of the rod in the region immediately adjacent to the start of the cap 22 is S With the cap diameter d C The ratio between the cap and the maximum extension d in the longitudinal direction L The maximum extension d of the portion 16 protruding radially beyond the rod R The ratio between φ and φ may be optimized for the cap 22 to ensure an oscillating mode.

[0246] Figures 5 to 8 A further exemplary embodiment of a sonotrode 1 according to the invention is shown, wherein Figure 6 yes Figure 5 Detailed view of the cap 22 of the sonotrode 1, Figure 8 yes Figure 7 Detailed view of the cap 22 of the sonotrode 1 .

[0247] and Figures 2 to 4 In contrast to the embodiment shown in FIG. 1 , the sharp edge 23 is limited to Figures 5 to 8 In other words, the cap 22 has a circumferential surface that includes sharp edges 23 only in the segment 17 of the circumferential surface.

[0248] The circumferential surface or at least the segment 17 of the circumferential surface comprising the sharp edge 23 is adapted to the desired location for treatment and non-treatment.

[0249] exist Figures 5 to 8 In the embodiment shown, the circumferential surface in the segment 17 comprising the sharp edge 23 comprises an additional recess 28 in said segment 17. This may, for example, improve the removal of debris from the treatment site.

[0250] In other words, the sharp edge 23 of the cap 22 is formed by an edge piece 29 which is arranged in the section 17 of the circumferential surface to which the sharp edge 23 is confined.

[0251] Two adjacent edge pieces 29 are separated from one another by a recess 28 .

[0252] Figures 5 to 8 The edge piece 29 shown in FIG. 1 is a further part of the portion 16 which is arranged further away from the longitudinal axis than the maximum extension 14 of the rod 21 .

[0253] The edge pieces 29 can act as individual (autonomous) vibrators excited by the central region (core) of the cap 22. In other words, each edge piece 29 can exhibit a vibration mode on its own. This allows for increased axial (proximal to distal) amplitude, thereby improving the ablation performance of the sonotrode.

[0254] according to Figures 5 to 8 The cap 22 of the embodiment of the present invention further has a first sharp edge 23.1 and a second sharp edge 23.2, the second sharp edge 23.2 being arranged more laterally with respect to the first sharp edge 23.1.

[0255] exist Figures 5 to 8 In the embodiment shown, the first and second sharp edges are formed by the transition between the distally facing convex surface 24 and the proximally facing surface of the mushroom-shaped cap 22, wherein the transition is not a direct transition but a transition via a surface 18 whose surface normal substantially coincides with the radial direction (radial direction relative to the longitudinal axis). In the embodiment shown, the surface 18 having a surface normal substantially coinciding with the radial direction is substantially formed by a portion of an imaginary surface around the longitudinal axis, wherein each point on the imaginary surface is at the same distance from the longitudinal axis.

[0256] Thus, a first sharp edge 23 . 1 is formed by the transition between the distally facing convex surface 24 and said surface 18 having a substantially radial surface normal, and a second sharp edge 23 . 2 is formed by the transition between the surface 18 having a substantially radial surface normal and the proximally facing surface of the mushroom-shaped cap 22 .

[0257] exist Figure 5 and Figure 6 In the embodiment of the present invention, the proximally facing surface of the mushroom-shaped cap 22 forms a substantially flat (planar) surface 25 at least in the transition region. The flat surface 25 extends at an opening angle 42 of 90 degrees relative to the rod 21.

[0258] exist Figure 7 and Figure 8In the embodiment of the present invention, the proximally facing surface of the mushroom-shaped cap 22 forms a concavity 26 at least in the transition region. This can increase the sharpness of the second sharp edge 23.2 and can improve the removal of debris from the treatment site. During operation of the sonotrode 1 as described above, this may also be advantageous in terms of the force vector generated by the sharp edge 23.2.

[0259] In particular, if the sharp edge ( Figure 7 and Figure 8 The second sharp edge 23.2 in the embodiment of the present invention is formed by a radially extending surface (concave surface 26 or convex surface 24, such as Fig.14 If an overhang 35 is formed as shown in the figure, the advantages of a sharper edge and a more favorable force vector are more obvious.

[0260] In order to meet the requirement that the center of mass 43 of the cap 22 is on the longitudinal axis 15, the cap may comprise at least two parts which are arranged in such a way that the cap comprises a rotational symmetry of order n about the longitudinal axis 15, where n is an integer but not 1, and / or the cap 22 may comprise, for example Fig.15 and Fig.16 The balancing weight (balancing mass) 41 shown in FIG.

[0261] exist Figure 7 and Figure 8 In the embodiment of the embodiment, the concavity of the concave surface 26 is only moderate. However, the concavity may be more pronounced.

[0262] exist Fig.13 The embodiment of FIG. 20 shows a more pronounced concavity, where the concavity makes the entire radial end portion of the cap 22 an overhang 35, rather than just the sharp edge 23. In addition, the concavity of the concave surface 26 is more pronounced than the convexity of the convex surface 24. This means that the longitudinal extension of the brim (longitudinal extension d L ) depends on the distance r from the longitudinal axis 15 and includes a minimum value between the longitudinal axis and the position of the sharp edge 23.

[0263] The smallest area in the extension of the cap 22 in the longitudinal direction can be regarded as an area 37 of reduced mechanical stability.

[0264] If the cap is based on Fig.13If the cap 22 is designed, the radially outermost portion of the cap 22 can act as a separate (autonomous) oscillator excited by the central region (core) of the cap 22. In other words, the radially outermost portion of the cap 22 can exhibit a vibration mode alone, wherein the vibration mode will also have a motion component in the radial direction. This can further improve ablation due to the hammering effect. However, if the cap 22 includes an nth order rotational symmetry about the longitudinal axis 15, where n is an integer but not 1, in particular an even number, or if the cap 22 is rotationally symmetric about the longitudinal axis (i.e., any angle of rotation will turn the cap on itself), the radial vibration of the radially outermost portion does not occur simultaneously with a significant excitation of the transverse oscillation mode of the entire sonotrode 1. These symmetry considerations also mean that the center of mass 43 of the cap is on the longitudinal axis.

[0265] Due to the minimal extension in the longitudinal direction, the radially outermost part, which can be used as a separate (autonomous) vibrator, generally has an oscillation mode whose oscillatory motion includes important directions in the radial and longitudinal directions. Therefore, the oscillation mode of the radially outermost part affects the hammering effect and the increased axial (near to far) amplitude. The combination of the hammering effect and the increased axial amplitude significantly improves the ablation efficiency of the sonotrode.

[0266] Fig. 9 Another exemplary embodiment of a sonotrode 1 according to the invention is shown. This embodiment comprises a plurality (that means at least two) of sharp edges 23, wherein the sharp edges are offset relative to each other along a distal to proximal direction. The distal to proximal direction is generally parallel to the longitudinal axis 15 of the sonotrode 1.

[0267] exist Fig. 9 In the illustrated embodiment, a plurality of sharp edges 23 are formed by a series of steps 20 disposed at a radially outermost portion of the cap 22. In the illustrated embodiment, the cap 22 includes a distally facing convex surface 24 and the steps 20 are disposed proximally of the convex surface 24. Each step forms a sharp edge 23 by including a transition from a generally radially oriented surface and a generally distal to proximal oriented surface.

[0268] The steps 20 are further offset with respect to their distance from the longitudinal axis 15. Fig. 9 In the embodiment shown, the offset is such that the sharp edge 23 formed by a step 20 is further from the longitudinal axis 15 than its distally adjacent step 20 and the sharp edge 23 of the distally adjacent step 20. Thus, the plurality of sharp edges 23 facilitate ablation during a movement of the sonotrode 1 in the distal direction, that is to say in a pushing movement.

[0269] Alternatively, the offset may be such that the sharp edge 23 formed by a step 20 is further from the longitudinal axis 15 than its proximally adjacent step 20 and the sharp edge of the proximally adjacent step 20. Thus, the plurality of sharp edges 23 facilitates ablation during a movement of the sonotrode 1 in the proximal direction, which means in a pulling movement.

[0270] Alternatively, the steps may form a serrated surface. In this embodiment, two protruding steps are separated by a recess. Thus, each protruding step forms two sharp edges offset in the distal to proximal direction. Thus, half of the plurality of sharp edges 23 contribute to ablation in a movement of the sonotrode 1 in the distal direction (this means in a pushing movement), and the other half of the plurality of sharp edges 23 contribute to ablation in a movement of the sonotrode 1 in the proximal direction (this means in a pulling movement).

[0271] In addition to the sharp edge formed by the step, the cap 22 may also have one or more additional sharp edges. For example, the transition from the distally facing surface (particularly the convex surface 24 (if any) in any embodiment discussed) to the step 20 and / or the transition from the step 20 to the proximally facing surface (such as the concave surface 26 in any embodiment discussed or the flat surface 25 in any embodiment discussed) may form a sharper edge.

[0272] In embodiments, it is contemplated that the series of steps 20 may be replaced by other elements that may be shaped to provide a plurality of sharp edges (23). For example, the steps may be replaced by ablated structures such as pyramids, intersecting protrusions and / or surface roughness. For example, the surface roughness may be provided by the additive manufacturing methods described above or by selective laser melting (SLM).

[0273] Fig.10 and Fig.11 A further exemplary embodiment of a sonotrode 1 according to the invention is shown. Fig.11 is a detailed view of the cap 22 of the sonotrode 1 of FIG. 12 . Fig.10 and Fig.11 The embodiment shown in FIG. 1 is similar to the embodiment including steps 20 forming a serrated surface.

[0274] exist Fig.10 and Fig.11 In the embodiment of the present invention, the serrated surface 34 is formed by tapered structures forming the sharp edge 23, wherein a plurality of tapered structures are arranged in a distal to proximal direction.

[0275] For example, the cap 22 may comprise a surface, in particular a surface of the portion 16 arranged further away from the longitudinal axis 15 than the maximum extension 14 of the stem 21, said surface having a surface normal substantially coinciding with the radial direction, but having protrusions and recesses forming a serrated surface 34. In the embodiment shown, the surface having a surface normal substantially coinciding with the radial direction is a surface around the longitudinal axis, wherein each point on the surface would be at the same distance from the longitudinal axis if the surface were not serrated.

[0276] Likewise, the cap may have one or more additional sharp edges in addition to the sharp edge formed by the serrated surface 34. For example, the transition from a distally facing surface (e.g., the convex surface 24 (if any) in any of the embodiments discussed) to the serrated surface 34 and / or the transition from the serrated surface 34 to a proximally facing surface (e.g., the concave surface 26 in any of the embodiments discussed or the flat surface 25 in any of the embodiments discussed) may form a sharper edge.

[0277] about Figures 2 to 4 and Figures 9 to 11 Any embodiment of the disclosed cap 22 may be formed to define therapeutic and non-therapeutic areas, such as with respect to Figures 5 to 8 As publicly.

[0278] In addition to or in lieu of the cap 22 configured to define treatment and non-treatment areas, a cap 22 may be provided such as Fig.12a and Figure 12b The sleeve 30 is shown by way of example in FIG. Fig.12a The schematic diagram of the appearance of the ultrasonic welding electrode 1 including the sleeve 30 is shown. Figure 12b Shown including according to Fig.12a sectional view of the ultrasonic welding electrode 1 with a sleeve 30 .

[0279] Fig.12a and Figure 12b The ultrasonic welding electrode 1 shown in FIG. 1 and combined with the sleeve 30 is based on Figures 2 to 4 However, any ultrasonic welding electrode according to the main or second aspect of the present invention may include Fig.12a and Figure 12b This is the case in particular if the sonotrode comprises a convex surface 24 facing distally.

[0280] The sleeve 30 is configured to accommodate at least a portion of the sonotrode 1 and to be mounted to the sonotrode 1 and / or an ultrasonic surgical instrument.

[0281] In the illustrated embodiment, when the sleeve 30 is mounted to the sonotrode 1 , the portion of the sonotrode 1 that is housed in the sleeve 30 comprises the rod 21 .

[0282] The sleeve 30 may be mounted with the sonotrode 1 at its proximal end 4 , for example at the distal end portion of the coupling 13 .

[0283] The sleeve 30 includes a lateral opening 31 designed so that the sharp edge 23 is not covered by the sleeve 30 in the action section. In other words, the lateral opening 31 is designed to expose a portion of the sharp edge 23 when the sleeve 30 and the sonotrode 1 are mounted on an ultrasonic surgical instrument for use.

[0284] like Fig.12a and Figure 12b The sleeve 30 shown by way of example in FIG. 1 is particularly advantageous in combination with a sonotrode 1 comprising means for supplying a coolant and / or irrigation fluid to the treatment site and / or removing debris, for example as Fig.17 and Fig.18 shown.

[0285] Fig.17 An exemplary embodiment of a sonotrode 1 is shown, comprising means for providing coolant and / or irrigation fluid to a treatment site and / or removing debris by comprising a central channel 46 , which opens to the distal side of the sonotrode 1 .

[0286] In other words, the sonotrode 1 comprises a central channel 46 , through which a liquid, in particular a coolant and / or an irrigation fluid, can be supplied to the distal region of the sonotrode 1 .

[0287] Additionally or alternatively, central channel 46 may be used to wick fluid and debris away from the area surrounding the treatment site.

[0288] Including Fig.17 The combination of the sonotrode 1 with the central channel 46 shown by way of example in FIG. 4 and the sleeve 30 is particularly advantageous in medical situations where spatial conditions lead to hemorrhage at the treatment site, that is, when the treatment site is located in a narrow area, as is the case in minimally invasive surgery (MIS) applications.

[0289] Fig.18 An exemplary embodiment of a sonotrode 1 is shown, which comprises means for supplying a coolant and / or an irrigation fluid to the treatment site and / or a device for removing debris by means of a lateral channel 47 which opens to an area arranged proximally of the sharp edge 23 and thus to the area of ​​the treatment site.

[0290] according to Fig.18 The sonotrode 1 of the exemplary embodiment comprises two lateral channels 47 .

[0291] In other words, the sonotrode 1 comprises two lateral channels 47 which, in the embodiment shown, are connected to a central supply channel 48 and through which liquid, in particular a coolant and / or an irrigation fluid, can be supplied to the proximal region of the sharp edge 23 .

[0292] Additionally or alternatively, the side channel 47 may be used to wick liquid and debris away from the area surrounding the treatment site, particularly from the area between the sharp edge 23 and the opening 49 of the side channel 47 .

[0293] exist Fig.18 In the embodiment shown, the lateral channel 47 opens in the flattened (tapered) region 12 of the proximal end 4 of the sonotrode 1. However, the lateral channel 47 may open anywhere in the shaft 21 or the cap 22, in particular if the sonotrode 1 is used in combination with a sleeve 30.

[0294] In particular, in the embodiment of the sonotrode 1 comprising a lateral channel 47 and a sleeve 30 , the orientation of the opening 49 of the lateral channel 47 is of secondary importance.

[0295] For example, the lateral channel 47 may open out in a further flattened (tapered) region 12 arranged in the rod 21 .

[0296] Including Fig.18 The combination of the sonotrode 1 with the lateral channel 47 shown by way of example in FIG. 4 and the sleeve 30 is particularly advantageous in "open" medical situations, where the spatial conditions in the area of ​​the treatment site do not or are insufficient to cause hemorrhage at the treatment site. In this case, the sleeve 30 directs the liquid to be provided to the treatment site, which means that Fig.18 In the illustrated embodiment, fluid / debris is aspirated distally, or for example directed away from the treatment site toward the opening of the lateral channel 47 .

[0297] Devices for providing coolant and / or irrigation fluid to the treatment site and / or removing debris, such as Fig.17 and 18 As shown, it is preferably arranged such that the oscillation behavior of the sonotrode 1 is changed due to the device. Fig.17 In the embodiment of FIG. 1 , this is accomplished by a central channel extending along the central axis 15 of the sonotrode. Fig.18 In an embodiment of the invention, this is accomplished by arranging the lateral channels in such a way that the sonotrode still has at least a rotational symmetry of order n, where n is an integer but not 1.

[0298] Relative to Fig.17 and Fig.18 The disclosed means for cooling and / or removing may be present in any embodiment of the sonotrode 1 according to the primary or second aspect of the invention.

[0299] Figures 13 to 16 A schematic diagram of a further exemplary embodiment of a cap 22 according to the invention is shown.

[0300] The above is for the radially outermost portion of the cap 22 including the region 37 of reduced mechanical stability and serving as a separate (autonomous) vibrator. Fig.13 Embodiments and basis Figure 7 and Figure 8 Examples of embodiments are discussed.

[0301] according to Fig.14 In the exemplary embodiment, the portion 16 of the cap 22 that protrudes radially more than the rod 21 includes a first overhang 35.1 and a first sharp edge 23.1 forming a distal region of the portion 16. The portion 16 also includes a second overhang 35.2 and a second sharp edge 23.1 forming a proximal region of the portion 16.

[0302] The portion 16 designed in this way, which protrudes further in the radial direction than the rod 21, has various advantages. Figure 7 and Figure 8 As discussed, the sharpness of the edge may be increased, the removal of debris from the treatment site may be improved, and the force vectors generated by the sharp edge during operation of the sonotrode 1 may be advantageous.

[0303] In addition, if Fig.14 The sonotrode including the cap 22 exemplarily shown in FIG. 1 can ablate in a push mode (ie the sonotrode is moved distally) and in a pull mode (ie the sonotrode is moved proximally).

[0304] Due to these advantages of a sonotrode having a first sharp edge 23.1 arranged in the distal direction and a second sharp edge 23.2 arranged in the proximal direction, the cap and the sonotrode according to any disclosed embodiment may have such first and second sharp edges, for example by Fig.14 The overhang 35 shown as an example in FIG.

[0305] Fig.15 and Fig.16 An exemplary embodiment of a sonotrode is shown which comprises a balancing weight (balancing mass) 41 which is arranged in such a way that the center of mass 43 of the cap 22 lies on the longitudinal axis 15 .

[0306] In accordance with Fig.15 In the embodiment of FIG. 2 , the balancing weight 41 is arranged inside the cap 22 , which means that the balancing weight 41 has no influence on the overall shape of the cap.

[0307] Fig.15The balancing weight 41 of the embodiment of is a region of density greater than the density of the rest of the cap 22. Said region has a mass center 45 arranged to balance the portion 16 which protrudes radially more than the rod 21 and moves the mass center 43 of the cap away from the longitudinal axis 15.

[0308] In other words, any structural deviations of the cap which result in the centre of mass 43 of the cap not being on the longitudinal axis 15 are balanced by the associated equalizing weight 41 so that the entire centre of mass 43 is on the longitudinal axis 15 .

[0309] Fig.16 An exemplary implementation of an alternative to the concept of a balancing weight (balancing mass) 41 is shown. According to this alternative, the balancing weight 41 is arranged outside the basic shape of the cap 22.

[0310] For example, the structural deviation of the balancing weight 41 from the cap causes the center of mass 43 of the cap to be not on the longitudinal axis 15, especially the portion 16 including the sharp edge 23 is a structural deviation having the same or similar shape as the structural deviation but arranged on the opposite side of the cap 22.

[0311] In the embodiment, the balancing weight 41 is a further portion 16 which protrudes radially further than the rod 21 with or without a sharp edge 23 .

[0312] Fig.16 Further shown are optional features of the region 37 of reduced mechanical stability including an elastic element 38. For example, the elastic element can improve the oscillatory behavior of the portion of the cap 22 that acts as a separate (autonomous) oscillator, e.g. Fig.13 This also means that any individual (autonomous) vibrator disclosed can be connected to the rest of the sonotrode via the elastic element 38.

[0313] Fig.19 An exemplary embodiment of a sonotrode 1 according to the second aspect of the invention is shown.

[0314] Fig.19 The sonotrode shown in satisfies some important requirements for ultrasonic welding of ablative tissues (e.g., bone tissue), such as mechanical stability, localization to the treatment site and controllability, the ability to ablate during forward and backward movement, and suppression of excitation of lateral oscillation modes, at least in some cases. Fig.19 The sonotrode shown in FIG. 1 includes a number of features that are or may be present in a sonotrode according to the main aspects of the invention.

[0315] Fig.19The sonotrode 1 shown in FIG. 1 has a proximal end 4 with a thread 13 and a distal end piece 5 with a shaft 21 and a cap 22. The cap 22 includes a convex shape 24 and at least one sharp edge 23. The cap 22 is designed and adapted to ablate or scrape tissue, for example, unwanted bone structures such as osteophytes. The sharp edge can be used to scrape or file tissue, while the surface (convex, arcuate surface) of the convex shape 24 is smooth and formed to protect the tissue.

[0316] The sonotrode 1 according to the second aspect also extends along a longitudinal axis 15 .

[0317] The sonotrode 1 shown includes the optional feature of a flattened (tapered) region 12 of the proximal end 4, which forms the transition between the proximal end 4 and the shaft 21, as described above. It further includes the optional feature of a further flattened (tapered) region 12 arranged in the shaft as discussed above.

[0318] exist Fig.19 In the sonotrode disclosed in , the portion 16 arranged further away from the longitudinal axis 15 than the maximum extension 14 of the rod 21 extends over a significant range of radial angles 19. This means that the sonotrode comprises a portion 16 having a radial extension relative to the longitudinal axis which is greater than the maximum distance and which extends over a significant range of radial angles 19. In particular, if the resulting cap 22 is not blade-shaped, the extension in the radial angle range 19 is significant.

[0319] exist Fig.19 In the illustrated embodiment, the radial angular extent 19 is greater than 20 degrees.

[0320] Furthermore, an embodiment according to the second aspect comprises at least one sharp edge 23 or at least a portion of a sharp edge arranged in a portion 16 which is arranged further away from the longitudinal axis 15 than the maximum extension 14 of the rod 21 (i.e. protrudes radially further than the rod 21) and extends over a significant range of radial angles 19.

[0321] according to Fig.19 The cap 22 comprises a substantially flat surface 25 comprising a protruding rib 27 having a sharp edge 23. The surface portions of the cap 22 different from the flat surface 25 form a convex shape (convex surface) 24 of the cap 22 (except for the region of the rod 21). These surface portions are smooth.

[0322] according to Fig.19 The cap 22 can be massive. This means that the interior of the cap 22, which is defined by the substantially flat surface 25 and the convex surface 24, can be filled with material, in particular "filled" with material forming the surface of the cap 22.

[0323] Fig. 20 Shown according to Fig.19 Detailed view of cap 22 with bulk cap 22.

[0324] Alternatively, according to Fig.19 The cap 22 may be formed like a spoon, which means having an inner unfilled convex surface 24. The ribs 27 may be located within the convex surface (or spoon) or may bridge the opposite edges of the convex surface 24. These ribs may have sharp edges 23, which may be raised relative to the edge of the spoon-like structure.

[0325] exist Fig.19 and Fig. 20 In the embodiment of the present invention, the portion 16 which is radially further away from the longitudinal axis 15 than the maximum extension 14 of the rod 21 comprises the (filled or unfilled) spoon-like shaped portion of the cap 22 which is furthest away from the longitudinal axis 15 .

Claims

1. A sonotrode (1) for an ultrasonic surgical instrument, the sonotrode comprising a shaft (21) extending along a longitudinal axis (15) and a cap (22) configured to perform an ablation operation on tissue using mechanical oscillation, wherein the cap comprises at least one portion (16) protruding radially further than the shaft, wherein the at least one portion comprises at least one sharp edge (23), wherein a surface arranged between the distal end of the shaft and the sharp edge of the portion is a concave surface (26), and / or the concave surface (26) extends at an opening angle (42) equal to or less than 90 degrees relative to the shaft, wherein the cap (22) comprises a distally facing convex surface (24), wherein the convex surface has a soft and / or smooth surface; The ultrasonic welding electrode comprises at least one of the following: a rod (21) having a tapered region (12); • a cap (22) comprising at least one region with a sharp edge (23) and connected to the body (50) of the cap by means of a region (37) of the cap which reduces the mechanical stability; • A cap (22) designed to include at least one oscillation mode excited by mechanical oscillations coupled into the cap via the rod (21).

2. The ultrasonic welding electrode (1) according to claim 1, wherein the surface of the cap (22) located between the distal end of the rod (21) and the sharp edge (23) is a concave surface, which is curved in the proximal direction to provide a portion (16) with an overhang (35).

3. The sonotrode (1) according to claim 1 or 2, wherein the cap (22) is designed to include at least one oscillation mode which can be excited by mechanical oscillations coupled into the cap via the rod (21).

4. The sonotrode (1) according to claim 3, wherein the cap (22) is designed to include at least one oscillation mode that can be excited by means of the sonotrode by mechanical oscillations coupled into the cap via the rod (21), the sonotrode including at least one of: • The diameter (d S ) is at most the relevant diameter of the cap (d C ) half; • the diameter of the largest possible circle that can be arranged completely within the cross section of the rod (21) is at most half the diameter of the smallest possible circle that encloses the cap in a cross section perpendicular to the longitudinal axis, the cross section of the rod being perpendicular to the longitudinal axis (15) and in the region of the rod immediately adjacent to the start of the cap (22), wherein the cross section of the cap is located at the point of maximum lateral extension of the cap; • Maximum longitudinal extension of the brim (d L ) is at most the maximum extension of the portion of the brim that projects radially further than the stem (d R ) half; • The longitudinal extension of the cap (22) depends on the distance from the longitudinal axis (15), wherein the longitudinal extension comprises a minimum value between the longitudinal axis (15) and the sharp edge (23).

5. The sonotrode (1) according to claim 1 or 2, wherein the sonotrode comprises a coupling (13) for coupling to a transducer (3), wherein the sonotrode is optimized for mechanical oscillations of a preset frequency by making the distance between the coupling and the cap half the wavelength of the preset frequency or a multiple of half the wavelength of the preset frequency.

6. The ultrasonic welding electrode (1) according to claim 1 or 2, wherein the at least one portion (16) protrudes radially further than the rod (21), and its radial extension within a radial angle range of 360 degrees is greater than the maximum radial extension of the rod (21) relative to the longitudinal axis (15).

7. The sonotrode (1) according to claim 1 or 2, wherein the sharp edge (23) is formed by at least one of the following: • Transition from convex to concave or with an opening angle of 90 degrees or less relative to the rod; • a transition from a flat, concave or convex first surface to a flat, concave or convex second surface, wherein the first and second surfaces are oriented differently; •Protrusions on convex, flat or concave surfaces.

8. The sonotrode (1) according to claim 1 or 2, wherein the sharp edge (23) is arranged at a radially outermost portion of the cap (22).

9. The sonotrode (1) according to claim 1 or 2, wherein the sharp edge (23) is arranged only in the segment (17).

10. The sonotrode (1) according to claim 1 or 2, wherein the sharp edge (23) is formed by a plurality of edge pieces (29).

11. The sonotrode (1) according to claim 1 or 2, wherein the sonotrode comprises at least two sharp edges offset in a proximal to distal direction relative to a longitudinal axis.

12. The sonotrode (1) according to claim 1 or 2, wherein the shaft (21) has a tapered region (12).

13. The sonotrode (1) according to claim 1 or 2, wherein the cap (22) comprises at least one region with a sharp edge (23) and connected to the body (50) of the cap by means of a region (37) of the cap which reduces the mechanical stability.

14. The sonotrode (1) according to claim 1 or 2, wherein the amplitude of the sharp edge (23) during use of the sonotrode is at most 100 micrometers.

15. The sonotrode (1) according to claim 1 or 2, wherein the amplitude of the sharp edge (23) during use of the sonotrode is 150 micrometers or more.

16. The sonotrode (1) according to claim 1 or 2, wherein the sonotrode is configured for minimally invasive surgery by comprising a rod (21) having a length corresponding to half the wavelength of a preset frequency of mechanical oscillation or a multiple of half the wavelength of a preset frequency of mechanical oscillation, and a sleeve (30) arranged or configured to be arranged around the rod to separate the rod from the outside of the sleeve.

17. The sonotrode (1) according to claim 1 or 2, wherein the surface of the sonotrode (1) has a convex microstructure.

18. The ultrasonic welding electrode (1) according to claim 1 or 2, wherein the surface of the ultrasonic welding electrode (1) has an average roughness R between 5 μm and 15 μm or between 5 μm and 20 μm. a .

19. The sonotrode (1) according to claim 1 or 2, wherein the sonotrode comprises a sleeve (30) arranged or configured to laterally surround the rod so as to separate the rod from the outside of the sleeve and the sharp edge (23) is exposed at least in the lateral direction.

20. The sonotrode (1) according to claim 1 or 2, wherein the sonotrode comprises a channel for supplying fluid to the treatment site and / or for removing fluid and / or debris from the treatment site.

21. An ultrasonic surgical instrument for ablating tissue, comprising: • a handpiece comprising an ultrasonic transducer (3); • The sonotrode (1) according to any one of claims 1 to 20, which is mechanically coupled to the transducer (3).

22. The ultrasonic surgical instrument according to claim 21, further comprising a sleeve (30) which is mounted or can be mounted to the handpiece and is designed to laterally surround the rod (21) and expose the sharp edge at least in a lateral direction when the sleeve is mounted to the handpiece and the ultrasonic welding electrode is connected to the ultrasonic transducer (3).

23. The ultrasonic surgical instrument according to claim 22, wherein the sleeve (30) is mounted or mountable to the handpiece such that it rotates about the longitudinal axis (15) of the sonotrode (1) without rotating the handpiece.

24. A method for producing a sonotrode (1) according to claim 1, wherein the sonotrode (1) is produced by using an additive manufacturing method.

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