Surgical cutting tool for the treatment of spondylophytes on a vertebral body

Abstract

Surgical cutting tool (1) for treating spondylophytes on a vertebral body (5) comprising a receiving section (2) rotatable about an axis of rotation for clamping in a tool holder and a tool section (3) comprising a truncated pyramid (4) with a first surface section (41) adjacent to the receiving section (2) for removing tissue and a second surface section (42) connected to the first surface section (41) via a radius section R2 and arranged at an end opposite the receiving section (2) for machining a posterior edge, wherein the first surface section (41) comprises at least one cutting edge (410) arranged spirally about the axis of rotation for removing tissue and wherein the receiving section (2) is connected to the adjacent first surface section (41) via a radius section R1,wherein the first surface section (41) comprises a diamond coating and the second surface section (42) comprises a lapped surface.

Description

[0001] The invention relates to a surgical cutting tool for the treatment of spondylophytes on a vertebral body.

[0002] The invention lies in the technical field of milling cutters for spinal surgery.

[0003] The spinal canal is a cylindrical space in the center of the vertebral column, running axially (vertically in humans, horizontally in domestic animals). Within this space lie the spinal cord and the nerve bundle of the cauda equina, protected by the spinal cord. Diseases of the segmental bony structure can lead to changes such as bony outgrowths (spondylophytes, spondylosis), ligament thickening, and osteoarthritis of the facet joints (spondylarthrosis), which can result in narrowing of the spinal canal (spinal stenosis). These disease-related changes in the shape and position of the bony structures affect the spinal nerves exiting the spinal canal at each segment. Any movement, especially in cases of lumbosacral instability, can lead to progressive narrowing of the spinal canal and painful irritation of the nerves exiting it.

[0004] Over the course of a person's life, the joints undergo progressive degeneration. This particularly affects the small vertebral joints. Considerable scientific research has already been undertaken to explain the underlying causes. That degeneration is a factor is undisputed. The fact remains that, regardless of the specific causes, the joints and their components change to such an extent that it ultimately leads to misalignments and therapy-resistant spinal pain, significantly impacting quality of life.

[0005] In spinal surgery, ball-tipped diamond burrs are used, among other methods, to treat spondylophytes, which are the cause of osteogenic cervical stenosis. These remain standard practice. Additionally, flat-shoe bone punches are used to remove any remaining bony growths on the vertebral body.

[0006] DE 10 2010 051 282 A1 discloses a microsurgical, diamond-coated processing head and a microsurgical tool, wherein the basic shape of the processing head is a disc with two side surfaces that curve convexly and symmetrically to a longitudinal axis of the shaft. The side surfaces touch over their largest diameter along a rim formed by the side surfaces.

[0007] DE 10 2016 107 549 A1 relates to a surgical milling cutter designed for removing bone and / or cartilage tissue, comprising a shaft extending along a longitudinal axis and rotatable about it, which is detachably connectable to a drive unit and has a proximal end that can be connected to a drive unit in a rotationally fixed manner and a distal end opposite this proximal end, wherein a milling surface is formed at the distal end, which surrounds the shaft completely and extends along the longitudinal axis of the shaft at the distal end, projects radially from the shaft and has a maximum milling surface radius.To avoid unintentional injuries to sensitive body structures, an atraumatic design is proposed such that a protective arrangement is provided at the distal end, wherein this has a distal bearing surface and a maximum radius of the protective arrangement to form a protective ring that encloses the maximum radius of the milling surface in a ring shape.

[0008] DE 10 2012 110 253 A1 discloses a medical milling device for separating or removing tissue from bone material. It has a rod-shaped body, at the distal end of which at least one material-removing tool is arranged in the circumferential region, and a proximal end can be connected to a drive for rotating the rod-shaped body about its longitudinal axis. The device is characterized in that the body has openings in the circumferential region where it is provided with the material-removing tool, which communicate with an internal channel in the body, and that the channel can be connected proximally to a vacuum source, so that tissue parts separated by the material-removing tool can be drawn into the channel through the openings and removed at the proximal end.

[0009] Quite often, in such procedures, the bone elements to be removed are directly adjacent to extremely important anatomical structures. These include, among others: nerves, roots, blood vessels, the meninges (membranes surrounding the brain and spinal cord), as well as the underlying brain or spinal cord tissue. Injury to these structures by the milling surface can lead to serious and not always reversible damage. A dural tear is the most common complication in spinal surgery.

[0010] During spinal canal decompression, it repeatedly became apparent that the tissue was incompletely removed. The resulting residual stenoses were visible on imaging despite the still-present clinical symptoms.

[0011] The invention aims to provide a surgical cutting tool that overcomes the disadvantages of the prior art and allows for the precise and complete removal of tissue from a vertebral body.

[0012] The problem is solved by a surgical machining tool for treating spondylophytes on a vertebral body, comprising the features of independent claim 1. Advantageous embodiments are the subject of the dependent claims.

[0013] The invention comprises a surgical cutting tool for treating spondylophytes on a vertebral body, comprising a receiving section rotatable about an axis of rotation for clamping in a tool holder and a tool section comprising a truncated pyramid with a first surface section adjacent to the receiving section for removing tissue and a second surface section connected to the first surface section via a radius section R2 and arranged at an end opposite the receiving section for processing a posterior edge, wherein the first surface section comprises at least one cutting edge arranged spirally about the axis of rotation for removing tissue and wherein the receiving section is connected to the adjacent first surface section via a radius section R1.The first surface section comprises a diamond coating, and the second surface section comprises a lapped surface. This allows for very precise and complete tissue removal from the vertebral body without damaging surrounding tissue such as the dura mater.

[0014] One advantageous aspect is that the first surface section has a diamond coating and the second surface section has a lapped surface. This keeps surface wear under stress to a minimum.

[0015] It is particularly advantageous if the diamond coating of the first surface section is a diamond dust coating. This allows the milling tool to be manufactured cost-effectively and to a high standard.

[0016] According to a preferred design, radius segment R1 has a concave shape and radius segment R2 has a convex shape. This allows for precise tissue removal at the posterior edge of the vertebral body without damaging the dura mater.

[0017] One advantageous feature is that the cutting edge has a U-shaped recess along the axis of rotation. This ensures that ablated material is removed from the surgical area as efficiently as possible, keeping the surgical area free of abraded material.

[0018] It has proven advantageous if the cutting edge extends, at least in some areas, from the base of the truncated pyramid to its top surface. This allows the entire cutting surface to be optimally utilized for even and rapid tissue removal, thus enabling precise work by the surgeon.

[0019] According to a preferred aspect, the angle α between the base and the lateral surface of the pyramidal stump lies in a range of 30° to 60°, preferably in a range of 40° to 50°, and particularly preferably in a range of 45° to 48°. This allows for the removal of residual bony growths on the vertebral body without additional instruments, thus reducing operating time.

[0020] Advantageously, the radius segment R2 lies in a range of 0.5 to 4 mm, preferably in a range of 0.75 to 3 mm, and particularly preferably in a range of 1 to 2 mm. This enables very precise tissue removal from the vertebral body and thus the greatest possible medical and biological compatibility of the surgical procedure while avoiding undesirable side effects.

[0021] One advantageous aspect is that the truncated pyramid is a regular truncated pyramid. This allows the maximum cutting surface to be utilized for tissue removal.

[0022] Particularly advantageous is a procedure for treating spondylophytes on a vertebral body using a surgical cutting tool, comprising the following steps: a. Providing a surgical cutting tool clamped in a tool holder; b. Removal of tissue by means of the cutting edge on the first surface section by rotation of the surgical cutting tool; and

[0023] Processing of a posterior edge using the second surface section by rotating the surgical cutting tool. This allows for complete tissue removal with only one tool, which greatly simplifies the procedure for the surgeon, significantly reduces operating time, and overall improves medical and biological compatibility while avoiding undesirable side effects.

[0024] The invention will be explained in more detail below with reference to a drawing.

[0025] They show: Fig. 1 a schematic representation of a surgical cutting tool according to the invention for the treatment of spondylophytes on a vertebral body; Fig. 2 a schematic representation of a surgical cutting tool according to the invention for the treatment of spondylophytes in application on a vertebral body; and Fig. 3 a schematic representation of a surgical cutting tool according to the state of the art.

[0026] Fig. Figure 1 shows a schematic representation of a surgical cutting tool 1 according to the invention for the treatment of spondylophytes on a vertebral body 5 in the form of a conical roller milling cutter.The cutting tool 1 comprises a receiving section 2 rotatable about an axis of rotation for clamping in a tool holder and a tool section 3 comprising a truncated pyramid 4 with a first surface section 41 adjacent to the receiving section 2 for removing fabric and a second surface section 42 connected to the first surface section 41 via a radius section R2 and arranged at an end opposite the receiving section 2 for machining a trailing edge, wherein the first surface section 41 comprises at least one cutting edge 410 arranged spirally about the axis of rotation for removing fabric and wherein the receiving section 2 is connected to the adjacent first surface section 41 via a radius section R1.

[0027] The first surface section 41 comprises a diamond coating, and the second surface section 42 comprises a lapped surface. Lapped surfaces have a matte-glossy appearance and are characterized by low wear under stress. According to DIN 8589, lapping is a machining process using loose abrasive particles dispersed in a liquid or paste (lapping compound), which are guided on a usually form-supporting counterpart (lapping tool) with the cutting paths of the individual particles being as undirected as possible. Individual abrasive tips are pressed into the workpiece and lapping tool, leaving crater-shaped, undirected machining marks. Lapping is a fine and ultra-fine machining process in which • High surface finishes (down to 0.1 µm) • extreme dimensional accuracy • Tight dimensional tolerances (down to IT 1) can be achieved regardless of the material hardness.

[0028] The diamond coating of the first surface section 41 is a diamond dust coating. Radius section R1 has a concave shape, and radius section R2 has a convex shape. Radius section R2 is in a range of 0.5 to 4 mm, preferably in a range of 0.75 to 3 mm, and particularly preferably in a range of 1 to 2 mm. Radius section R1 is a groove. Radius section R1 is in a range of 1 to 5 mm, preferably in a range of 2 to 4 mm, and particularly preferably in a range of 2.5 to 3.5 mm. Radius section R1 and radius section R2 each have a U-shape.

[0029] The cutting edge 410 has a U-shaped recess along the axis of rotation. The cutting edge 410 extends at least partially from the base of the truncated pyramid 4 to the top surface of the truncated pyramid 4. The angle α between the base and the lateral surface of the truncated pyramid 4 lies in a range of 30° to 60°, preferably in a range of 40° to 50°, and particularly preferably in a range of 45° to 48°. The truncated pyramid 4 is a regular truncated pyramid.

[0030] In Fig. Figure 2 shows a schematic representation of a surgical cutting tool 1 according to the invention, which is used in a method for treating spondylophytes on a vertebral body 5. The method comprises the steps: a. Providing a surgical cutting tool clamped in a tool holder 1; b. Removal of tissue by means of the cutting edge 410 on the first surface section 41 by rotation of the surgical cutting tool 1; and c. Machining of a trailing edge using the second surface section 42 by rotating the surgical cutting tool 1.

[0031] Fig. Figure 3 shows a schematic representation of a state-of-the-art surgical cutting tool 1 in the form of a ball-shaped diamond burr. These are still used as standard practice in spinal surgery for the treatment of spondylophytes, which are the cause of osteogenic cervical stenosis. Subsequently, flat-shoe bone punches are used to remove any remaining bony growths on the vertebral body.

Claims

[1] Surgical cutting tool (1) for treating spondylophytes on a vertebral body (5) comprising a receiving section (2) rotatable about an axis of rotation for clamping in a tool holder and a tool section (3) comprising a truncated pyramid (4) with a first surface section (41) adjacent to the receiving section (2) for removing tissue and a second surface section (42) connected to the first surface section (41) via a radius section R2 and arranged at an end opposite the receiving section (2) for machining a posterior edge, wherein the first surface section (41) comprises at least one cutting edge (410) arranged spirally about the axis of rotation for removing tissue and wherein the receiving section (2) is connected to the adjacent first surface section (41) via a radius section R1,wherein the first surface section (41) comprises a diamond coating and the second surface section (42) comprises a lapped surface. [2] Surgical cutting tool (1) according to claim 1, wherein the diamond coating of the first surface section (41) is a diamond dust coating. [3] Surgical cutting tool (1) according to one of the preceding claims, wherein the radius section R1 has a concave shape and the radius section R2 has a convex shape. [4] Surgical cutting tool (1) according to one of the preceding claims, wherein the cutting edge (410) has a U-shaped recess along the axis of rotation. [5] Surgical cutting tool (1) according to one of the preceding claims, wherein the cutting edge (410) extends at least partially from the base of the truncated pyramid (4) to the top surface of the truncated pyramid (4). [6] Surgical cutting tool (1) according to one of the preceding claims, wherein the angle α between the base and the lateral surface of the pyramid stub (4) is in a range of 30° to 60°, preferably in a range of 40° to 50°, particularly preferably in a range of 45° to 48°. [7] Surgical cutting tool (1) according to one of the preceding claims, wherein the radius section R2 is in a range of 0.5 to 4mm, preferably in a range of 0.75 to 3mm, particularly preferably in a range of 1 to 2mm. [8] Surgical cutting tool (1) according to one of the preceding claims, wherein the truncated pyramid (4) is a regular truncated pyramid.

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