US-12616483-B2 - Device and method for perforating a dense bone layer

Abstract

A device for cutting bone tissue and, more particularly, a sonotrode suitable for use with an ultrasonic surgical instrument. The sonotrode has a head and a distal end piece, the distal end piece being equipped as a rectangular blade for cutting bones using mechanical vibration. The sonotrode has at least one structural element and the structural element is selected from the group including: a support structure, a lateral depression on each side, an increased width of the blade together with a slit at the distal end of the blade, or at least one lateral rib.

Inventors

• Jörg Mayer
• Andrè Schwery
• Loïc Sottas
• Dominique Neuhaus

Assignees

• BOSONIC AG

Dates

Publication Date

20260505

Application Date

20190924

Priority Date

20190308

Claims (20)

1. 1 . A sonotrode for an ultrasonic surgical instrument having a head and a distal end piece, the distal end piece being a blade for cutting bones using mechanical vibration, wherein the blade is flat and extends in a plane defined by the blade, wherein a width of the blade increases toward a distal end of the blade, and wherein the distal end of the blade is arcuate and the blade has exactly one slit, and wherein the slit is at the distal end of the blade and separates the blade into first and second distal blade portions, and wherein a width of the slit increases toward a distal end of the slit and the arcuate distal end of the blade such that a width of each of the first and second distal blade portions decreases toward the arcuate distal end of the blade.
2. 2 . The sonotrode according to claim 1 , wherein the sonotrode comprises a support structure attached to the proximal end of the blade.
3. 3 . The sonotrode according to claim 2 , wherein the support structure has the shape of a ring.
4. 4 . The sonotrode according to claim 3 , wherein the support structure further comprises a cross beam.
5. 5 . The sonotrode according to claim 2 , wherein the support structure has the shape of an arc.
6. 6 . The sonotrode according to claim 5 , wherein the apex of the arc points towards the distal end of the blade.
7. 7 . The sonotrode according to claim 1 , wherein the sonotrode comprises a lateral depression on each side.
8. 8 . The sonotrode according to claim 7 , wherein the lateral depressions have the same depth and are symmetrically arranged within the blade.
9. 9 . The sonotrode according to claim 7 , wherein the lateral depressions have each a depth of 0.7 mm-1.2 mm.
10. 10 . The sonotrode according to claim 7 , wherein the blade of the sonotrode has channels running from the area of the depression to the edge of the blade.
11. 11 . The sonotrode according to claim 7 , wherein the lateral depression has at least two different levels.
12. 12 . The sonotrode according to claim 1 , wherein the slit has one of a V-shape, a U-shape or a Y-shape.
13. 13 . The sonotrode according to claim 1 , wherein the slit runs from a most distal point of the blade distal end towards the head of the sonotrode.
14. 14 . The sonotrode according to claim 1 , wherein the sonotrode comprises at least one rib.
15. 15 . The sonotrode according to claim 14 , wherein the sonotrode has at least one lateral rib on each side.
16. 16 . The sonotrode according to claim 14 , wherein the sonotrode has at least two lateral ribs on each side.
17. 17 . The sonotrode according to claim 14 , wherein the at least one rib runs along the central axis of the sonotrode.
18. 18 . The sonotrode according to claim 14 , wherein the at least one rib runs along the head and the distal end piece of the sonotrode.
19. 19 . The sonotrode according to claim 14 , wherein the at least one rib runs only along the distal end piece of the sonotrode.
20. 20 . The sonotrode according to claim 14 , wherein the at least one rib has a flattened distal end.

Description

BACKGROUND OF THE INVENTION Field of the Invention The invention resides in the field of medical technology and concerns a device for cutting bone tissue. It relates in particular to a sonotrode suitable to be used with an ultrasonic surgical instrument. Description of Related Art Among the cutting devices for cutting bone tissue, ultrasonic instruments are particularly efficient. These instruments include a cutting head that for the process is pressed against the bone tissue and is set into ultrasonic oscillation. The cutting process by these instruments is basically based on a local smashing of bone tissue. Transport of debris away from the cutting location as well as cooling are major issues. Cutting devices for cutting bone tissue, for example in osteotomy processes, on the one hand need to be equipped to cut through very dense and strong cortical bone tissue, and this at different angles (because of different access situations). On the other hand, cutting devices need to be capable of cutting deep into for example cancellous bone tissue. Prior art instruments include instruments with a cranked cutting device. The advantage using said instruments is a high amplitude in transverse direction. The main disadvantage of said instruments is their high pressure sensitivity: such cranked cutting devices are not sufficiently stiff in working (forward) direction. WO 2013/057179 discloses a sonotrode for a surgical instrument. The sonotrode head serves as cutting device extending in a longitudinal direction. It has a plurality of perforations extending in transverse direction through the sonotrode head. The perforations have an oblong shape and are at an angle between 30° and 80° to the longitudinal direction, whereby the sonotrode head gains an elasticity and, when subject to the ultrasonic vibrations, makes a pitching motion in the plane defined by the sonotrode head. According to WO 2013/057179, nevertheless a sufficient stiffness for applying a pressing force is preserved. The cutting surface of the sonotrode head further includes indentations that assist a removal of dissolved bone material. US 2015/0005771 A1 describes sonotrodes having a planar blade body, wherein the blade body has two lateral sides and a shallow recess. These sonotrodes have a shank with an outlet communicating with the recess, thereby enabling liquid flow into the recess. The blade further has a through hole extending between the lateral surfaces of the blade body and enabling liquid flow from the recess to an opposing side of the blade. US 2012004729 A1 describes cutting instruments with a longitudinal blade having a cutting edge build by a rim around an opening extending through the blade. The cutting takes place by rotation not by oscillation. The ultrasonic surgical instrument BoneScapel® has a rather thick sonotrode of more than 1 mm thickness with a circumferentially flattened tip or distal end of the blade. Thus, it includes a thick sonotrode with sharpened edges to cut the bone. SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved sonotrode for an ultrasonic surgical instrument suitable for cutting bones using mechanical vibration as well as an ultrasonic surgical instrument for cutting bones, including an improved sonotrode and methods for manufacturing these sonotrodes. One goal to be achieved by the improved sonotrodes is a better cutting performance for cortical bone. Cortical bone is dense and compact. Thereby the reduction of heat produced during cutting of bones is envisaged. In addition, it would be favorable to be able to lengthen the cutting surface of the sonotrode in order to allow deeper bone cuts such as osteotomy. One problem for long sonotrodes are bending movements such as oscillations out of plane, which have to be avoided. At the same time a thicker blade of the sonotrode should be avoided. Therefore, the blade does not need a sharpened distal end as cutting edge. Therefore, the present invention refers to a sonotrode for an ultrasonic surgical instrument having a head and a distal end piece, the distal end piece being equipped as a rectangular blade for cutting bones using mechanical vibration, wherein the sonotrode includes at least one structural element and wherein said element is selected from the group comprising: a support structure, a lateral depression on each side, an increased width of the blade together with a slit at the distal end of the blade, or at least one lateral rib. A first aspect of the invention relates to a sonotrode for an ultrasonic surgical instrument having a head and a distal end piece, the distal end piece being equipped as a blade for cutting bones using mechanical vibration, wherein the blade has a lateral depression on each side. The blade may be mainly rectangular. Nevertheless, the distal end of the blade may be arcuate or the blade may have rounded ends. The term “proximal” as used herein refers to the nearest to the point of attachment to