Spinal milling, spinal milling systems, and surgical methods for bone structures in the spinal region

Abstract

The present invention relates to a spinal milling machine for surgically altering bone structures in the spinal region, the spinal milling machine having a distal end face with milling teeth having a tooth profile with at least two teeth, and further having an axial through-hole for accommodating another spinal milling machine. The present invention further relates to a spinal milling machine system comprising a first spinal milling machine and a second spinal milling machine, wherein the second spinal milling machine is accommodating within the axial through-hole of the first spinal milling machine and has milling teeth having a tooth profile on its distal end face, and to a method for surgically altering bone structures in the spinal region at a surgical site using a spinal milling machine according to the present invention.

Description

Technical Field

[0001] The present invention relates to a spinal milling cutter, a spinal milling cutter system including the spinal milling cutter, and a method of surgically treating a bone structure in a spinal region using the spinal milling cutter at a surgical site.

Background Art

[0002] From the prior art, spinal milling cutters with a distal end face having a cutting edge are known for surgically treating bone structures in the spinal region, thereby forming access to the intervertebral disc space through the bone structure of the vertebra.

[0003] However, with known spinal milling cutters, it is only possible to surgically treat the bone structure of the spinal region usually only at a constant diameter corresponding to the outer diameter of the spinal milling cutter. When a change in the diameter of the surgical range, particularly an enlargement thereof, is desired, the initially used spinal milling cutter has to be laboriously removed from the surgical site and replaced with another spinal milling cutter having a larger surgical diameter.

[0004] This significantly prolongs the treatment time and markedly increases the risk of complications.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, an object of the present invention is to provide a spinal milling cutter that can surgically treat the bone structure of the spinal region more flexibly, simultaneously more safely and quickly.

Means for Solving the Problems

[0006] The problem of the present invention is solved by a spinal milling machine having the features of claim 1. This is a spinal milling machine for surgically operating on the bone structure of a spinal region having a distal end face with a tooth-shaped milling tooth having at least two teeth, the milling machine further having an axial opening for accommodating another spinal milling machine. The problem of the present invention is further solved by a spinal milling machine system according to claim 16. The spinal milling machine system of the present invention comprises a first spinal milling machine of the present invention and a second spinal milling machine that can be accommodated within the axial opening of the first spinal milling machine, the second spinal milling machine having a distal end face with a tooth-shaped milling tooth.

[0007] Furthermore, the problems of the present invention are solved by the method according to claim 26. This method is a method for surgically altering the bone structure of the spinal region at a surgical site using the first spinal milling machine of the present invention, in particular the spinal milling system of the present invention. The first spinal mill, together with another spinal mill housed within the axial opening of the first spinal mill, is introduced to the surgical site along a guide means, wherein the guide means is positioned within the axial opening of the first spinal mill, particularly within the axial opening of the other spinal mill. The first spinal milling machine is rotated together with another spinal milling machine to ensure that the bone structure of the surgical site is operated on along a predetermined path. • The step of removing another spinal flap from the surgical site, The first step involves rotating the spinal milling machine so that the desired surgery on the bone structure at the surgical site can be performed. • The first step is to remove the spinal flap from the surgical site, Includes.

[0008] In this invention, the distal direction refers to the surgical site side, and the proximal direction refers to the surgeon or the user of the spinal milling machine of this invention side. Following the three-dimensional cylindrical coordinate system, the axial direction refers to the direction parallel to the extension direction of the spinal milling machine, and the radial direction refers to the direction outward from the extension axis of the spinal milling machine, or the direction outward from the outside toward that axis, and the direction perpendicular to these. The circumferential direction is the direction perpendicular to both the axial and radial directions.

[0009] The present invention is based on the fundamental idea that providing an axial opening in a spinal mill creates a structurally particularly simple possibility for accommodating another spinal mill. In particular, during the procedure, the other spinal mill is guided through the axial opening of the outer spinal mill of the present invention, and due to the relatively small outer diameter of the other spinal mill, further, and especially more precise, surgery on the bone structure of the spinal region can be performed almost uninterrupted, without the need to painstakingly remove at least the outer spinal mill of the present invention from the surgical site. This simplifies and speeds up the procedure, reduces the risk of complications, and allows for greater flexibility in surgery on the bone structure.

[0010] According to the present invention, it is also possible to perform a first surgery on the bone structure of the spinal region using another spinal mill having a relatively small surgical diameter and at least partially housed within the axial opening of the spinal mill of the present invention, thereby reducing the risk of unnecessary tissue damage. The other spinal mill is safely guided by the spinal mill of the present invention surrounding it. Simultaneously with or immediately after the use of the other spinal mill, surgery on the bone structure can be performed with a relatively large surgical diameter using the first spinal mill of the present invention, without the need to remove the other spinal mill from the surgical site in a troublesome or complication-prone manner. Therefore, the present invention particularly enables a safer expansion of the surgical diameter during the procedure.

[0011] The milling teeth formed on the distal end face of the spinal milling tool allow surgery on bone structures to be performed in a safe manner, primarily controlled by the distal end face. The spinal milling tool of the present invention is specifically configured to operate on bone structures, allowing the spinal milling tool to mill axially into the bone structure at the surgical site. After surgery, the spinal milling tool of the present invention can remain in a position determined by the user of the bone structure, maintaining a certain degree of retention there.

[0012] Subsequently, another bone milling tool is pushed through the axial opening of the spinal milling tool of the present invention and then used in a predetermined manner, allowing surgery on the bone structure to continue with the other spinal milling tool at least partially housed within the spinal milling tool of the present invention, and this subsequent surgery is performed with a structurally smaller surgical diameter. In this way, the spinal milling tool of the present invention functions as a kind of protective sheath and guide for the other spinal milling tool, eliminating the risk of damage to nerves and soft tissues near the surgical site, as the other spinal milling tool, in particular, may have sharp blades or cutting edges. On the other hand, as described above, surgery on the bone structure of the spinal region is first performed with the other spinal milling tool housed within the axial opening of the first spinal milling tool, and the first spinal milling tool functions as a guide for the other spinal milling tool. After surgery on the bone structure with the other spinal milling tool, further surgery on the bone structure can be performed with the first spinal milling tool, and the first spinal milling tool can be pushed along the other spinal milling tool towards the surgical site. This allows for a safer enlargement of the surgical diameter. Furthermore, the risk of damage to nerves and soft tissues near the surgical site due to the first spinal milling tool slipping is reduced.

[0013] The spinal milling machine of the present invention is preferably configured so that surgery on the bone structure is performed as the spinal milling machine rotates around its extending axis. Preferably, the extending axis of the spinal milling machine is located within an axial opening. The axial opening can extend along the entire length of the spinal milling machine and may also be called a lumen or cannulation. In an advantageous embodiment of the present invention, the spinal milling machine is configured to be substantially cylindrical. The spinal milling machine of the present invention may have an outer diameter of 4 mm to 9 mm, preferably 7 mm to 8 mm, for example about 7.3 mm. The spinal milling machine of the present invention may have a working length of 150 mm to 350 mm, preferably 220 mm to 250 mm, for example about 235 mm.

[0014] Preferably, to improve surgery on bone structures, the tooth shape of the vertebral milling machine is configured at least partially as a cutting edge. In a preferred improved form of the vertebral milling machine, the outer edge of at least one tooth is located on the outer diameter of the distal end face of the vertebral milling machine, and / or the edge of at least one tooth tapers parallel to the axial direction toward the distal end face of the vertebral milling machine.

[0015] Preferably, the distal end face of the spinal milling machine has a chamfer that is particularly convex to prevent damage to nerves and soft tissue structures around the surgical site. Therefore, the chamfer can be configured to be non-traumatic. In a further improved embodiment of the present invention, the distal end face of the spinal milling machine has a concave chamfer, configured to ensure cutting capability across the entire distal end face. Thus, another spinal milling machine that can be housed within the axial opening of the spinal milling machine of the present invention can be similarly configured.

[0016] Preferably, at least one tooth of the tooth shape is oriented distally and / or radially. Particularly preferably, all teeth of the tooth shape are oriented distally and / or radially. Radially oriented teeth result in surgery on the bone structure primarily via the outer surface of the spinal mill when used, whereas with distally oriented teeth, the surgery is performed rather via the distal end surface of the spinal mill. In an improved embodiment of the present invention, the spinal mill may be defined as having two tooth shapes. The first tooth shape has radially oriented teeth, and the second tooth shape has distally oriented teeth, thereby combining the advantages of both described above. The tooth shapes may be axially offset from each other.

[0017] At least one tooth in the tooth profile does not have to be mirror-symmetric, and that tooth may have two radial ridges having different radial heights. In particular, a stepped transition is formed between the radial ridges of one tooth. If a tooth has multiple radial ridges, the tooth profile may have multiple steps and therefore be configured in a stepped manner. Stepped transitions between radial ridges, especially in a stepped form, can improve surgery based on the sharp edges of the teeth formed thereby. Not all teeth are mirror-symmetric, and in particular, each tooth may have two radial ridges having different radial heights.

[0018] Preferably, at least one tooth of the tooth profile has a first side and a second side, and the inclination of the first side is greater than the inclination of the second side. The inclination of the sides may relate particularly in the axial and / or radial directions. The first side may be positioned in front of or behind the second side with respect to a given rotational direction during use of the spine milling machine.

[0019] Preferably, two adjacent teeth in the tooth shape are separated from each other by parabolic recesses, thereby allowing for the incorporation of the surgically treated bone structure and ultimately its removal from the surgical site through the recesses in the tooth shape.

[0020] In an advantageous refinement of the invention, the spinal milling cutter has a threaded portion on the proximal side of the milling teeth, whereby surgical treatment of the bone structure via the outer peripheral surface of the spinal milling cutter is advantageously made possible. Furthermore, in this way a perforating surgical treatment of the bone structure can be carried out, so that the spinal milling cutter is also configured as a spinal drill. As a further advantage, after the surgical operation the spinal drill is in a state of being screwed into the bone structure, and unintentional removal due to tensile forces in the proximal direction can be avoided. The removed bone structure can also be carried out via the thread of the threaded portion. Preferably, the thread of the threaded portion is at least partially configured as a cut thread.

[0021] Preferably, the thread portion is formed by the tooth profile extending towards the proximal side. By the continuous transition between the tooth profile and the thread portion thus obtained, both the surgical characteristics of the spinal milling cutter and the removal of the surgically treated bone structure are improved.

[0022] Preferably, the threaded portion is made to have an axial length in the range of 10 mm to 90 mm, preferably in the range of 20 mm to 75 mm, and most preferably about 60 mm.

[0023] Preferably, the threaded portion has a thread pitch of 60° to 85°, particularly 70° to 85°, most preferably 75° to 80°, for example 75° or 80°.

[0024] In an advantageous refinement of the invention, the tooth profile has teeth with at least one triangular basic shape, the corners of which may be rounded. At least one tooth of the tooth profile may be configured to be mirror-symmetrical. In a refinement of the invention, preferably the tooth tip facing in the distal direction is made to be inclined along and / or against the direction of rotation of the spinal milling cutter. Advantageously, all the teeth of the tooth profile may face in the distal direction.

[0025] Preferably, the distal end face of the spinal mill has a distal projection, and the projection in particular has additional teeth, which improves the distal surgical characteristics of the distal end face of the spinal mill. The projection may have an axial length of 1 mm to 5 mm, preferably 3 mm. The projection may be radially centered with respect to the longitudinal axis of the spinal mill, or it may have an opening that forms part of the axial through-hole of the spinal mill. The distal projection has an elliptical, particularly circular, cross-section, and the cross-section of the distal projection is smaller than the outer diameter of the spinal mill. In particular, if the projection has additional teeth, this reduces the risk of damage to nerves and surrounding soft tissues that are not being surgically treated.

[0026] The tooth profile of the protruding portion may be configured to be mirror-symmetric, and in particular, the tooth profile of the protruding portion may be provided with teeth having a triangular base. In yet another configuration, the tooth profile may be not mirror-symmetric, and preferably such teeth have two radial ridges having different radial heights, with a stepped transition portion between them.

[0027] It is advantageous if the proximal end of the spinal milling cutter has a connecting piece configured especially for the accommodation of another spinal milling cutter. The connecting piece of the spinal milling cutter can be configured especially for a rotationally fixed and / or detachable connection with another spinal milling cutter. By means of a detachable connection, if the spinal milling cutter of the invention is securely held in the bone structure to be operated, for example, another spinal milling cutter can be easily removed from the spinal milling cutter of the invention. In particular, if teeth facing in the distal direction are provided on the distal end face of another spinal milling cutter, this eliminates the risk of damage to the nerves and soft tissue structures around the surgical site. In one form of the invention, the connecting piece is made to function as a trailing body for driving the spinal milling cutter. Preferably, the connecting piece has a triangular basic shape in cross section. For better connectivity between the spinal milling cutter of the invention and another spinal milling cutter, the connecting piece of the spinal milling cutter of the invention has an internal space, and the internal space is configured complementarily to the connecting piece of another spinal milling cutter, whereby a form-fitting connection possibility between the spinal milling cutter of the invention and another spinal milling cutter can be obtained. The inner contour of the connecting piece of the spinal milling cutter of the invention may be configured complementarily to the outer contour of the connecting piece of another spinal milling cutter.

[0028] In addition to the spinal milling cutter of the invention and a second spinal milling cutter, the spinal milling cutter system of the invention can include further instruments for spinal surgery. In the context of the invention, the second spinal milling cutter of the spinal milling cutter system can correspond to the above-mentioned another spinal milling cutter. The second spinal milling cutter may have at least one of the features mentioned above in connection with the spinal milling cutter of the invention. The second spinal milling cutter may be configured as the spinal milling cutter of the invention. The spinal milling cutter system may include at least one of the following instruments, namely a guide wire, a guide rod, a guide sleeve, a cone, a dilator, a working cannula, a protective sleeve, a trocar, a needle, a hollow needle, a Jamshidi needle.

[0029] The spinal milling system of the present invention is configured such that a second spinal milling cutter is detachably connected to a first spinal milling cutter. Preferably, the second spinal milling cutter is rotatably fixed to the first spinal milling cutter. The second spinal milling cutter may be detachably housed within the first spinal milling cutter. Preferably, the second spinal milling cutter is housed within an axial through-hole of the first spinal milling cutter and / or connected to the first spinal milling cutter. In a further embodiment of the present invention, the second spinal milling cutter is axially fixed to the first spinal milling cutter. Preferably, the second spinal milling cutter is detachable proximal to the first spinal milling cutter.

[0030] Preferably, the second spine milling cutter is rotatably fixed to the first spine milling cutter. The second spine milling cutter is axially fixed to a predetermined position relative to the first spine milling cutter, thereby preventing the second spine milling cutter from being unintentionally removed from the first spine milling cutter. The connection between the first and second spine milling cutters may be configured for axial fixing and / or rotation prevention.

[0031] Preferably, the second spinal milling cutter is configured as another spinal milling cutter of the present invention, and therefore the second spinal milling cutter also has an axial through-hole, particularly for accommodating an additional third spinal milling cutter. The axial through-hole of the second spinal milling cutter may be configured for accommodating a guide means, so that the second spinal milling cutter can reach the place of use along the guide means. The guide means may be configured as a drill and / or a guide rod and / or a guide wire. In particular, the distal end face of the second spinal milling cutter may be rounded. In an advantageous improved embodiment of the present invention, the rounding is configured to be concave, particularly in combination with the distally oriented teeth of the second spinal milling cutter, so as to ensure its cutting capability, especially over the entire distal end face.

[0032] Preferably, the second spinal milling cutter has a proximal connecting piece, the outer contour of which is configured to be particularly complementary to the inner contour of the connecting piece of the first spinal milling cutter. In an improved embodiment of the present invention, the connecting piece of the second spinal milling cutter has a distal connecting piece, the outer contour of which is configured to correspond to the inner contour of the connecting piece of the first spinal milling cutter. This provides a structurally simple connection between the first and second spinal milling cutters. In a further configuration of the present invention, the second spinal milling cutter is rotatable, and the first spinal milling cutter can be made rotatable based on a shape-coupled connection with the second spinal milling cutter, particularly in synchronization with it.

[0033] Preferably, a drive unit is provided that is configured to rotate the first vertebral milling machine and / or the second vertebral milling machine, thereby performing surgery on the desired bone structure at the work site.

[0034] In a further embodiment of the present invention, the spinal milling machines are made rotatable independently of each other. This is particularly advantageous when the first spinal milling machine is to primarily operate on the bone structure at the work site over a user-specified distance and then remain in place, morphologically coupled to the remaining bone structure. Subsequently, with the first spinal milling machine not rotated, the second spinal milling machine can be used for further operation of the bone structure, thereby avoiding damage to nerve cells and surrounding soft tissue.

[0035] Preferably, the second spinal mill has an axial through-hole, and particularly when connected to the first spinal mill, the axial through-hole is concentric with respect to the axial through-hole of the first spinal mill. The diameter of the axial through-hole of the second spinal mill is adjusted to match the outer diameter of a guide means, particularly a cone, especially a blunt-ended guide rod or guide wire, so that the second spinal mill, particularly in combination with the first spinal mill, is given safe and reliable guidance of the work area via the already placed guide means. The inner diameter of the axial through-hole of the first spinal mill can correspond to the outer diameter of the second spinal mill, so that the surgically operated bone structure is removed from the work area as far as possible via the outer circumferential surface of the spinal mill, and not particularly lodged and jammed in the gap between the first and second spinal mills. In this way, the risk of spinal mill entanglement is reduced.

[0036] The axial through-hole of the second spine milling cutter may extend along its entire axial length. Preferably, the second spine milling cutter has an outer diameter of 3 mm to 7 mm, particularly about 4 mm. The diameter of the axial through-hole of the second spine milling cutter may be 1 mm to 4 mm, preferably about 2.4 mm. The second spine milling cutter may have a working length of 160 mm to 360 mm, particularly 230 mm to 280 mm, preferably about 256 mm. The axial length of the spine milling cutter system may correspond to the axial length of the second spine milling cutter.

[0037] Preferably, at least one tooth of the tooth profile of the second vertebral milling machine has a triangular basic shape, with one side of the tooth having an inclination of about 90°. In an improved embodiment of the present invention, the teeth of the tooth profile have undercuts. In particular, at least one tooth is inclined toward or opposite to the rotational direction of the vertebral milling machine.

[0038] Preferably, the tooth profile of the second vertebral milling machine extends proximal to form the threaded portion of the second vertebral milling machine. For example, the threaded portion is formed by the tooth profile extending proximal while rotating around the extending axis of the vertebral milling machine. The threaded portion of the second vertebral milling machine can have an axial length of 10 mm to 40 mm, particularly about 20 mm. In particular, the threaded portion of the second vertebral milling machine is made to have the same gradient and / or the same direction of rotation as the threaded portion of the first vertebral milling machine. This creates a nearly seamless transition between the threaded portion of the second vertebral milling machine and the threaded portion of the first vertebral milling machine, which facilitates the removal of surgically treated bone structures, i.e., bony structures or bone material.

[0039] It is preferable that the second vertebral milling cutter protrudes from the first vertebral milling cutter, particularly its distal end face, by an axial length of 0.5 mm to 10 mm, especially 1.5 mm to 6 mm, preferably about 4 mm.

[0040] The spinal milling machine of the present invention can be configured for surgery on bone structures in the spinal joint region, particularly in the articular process region. The spinal milling machine of the present invention is preferably configured for surgery on the superior articular process.

[0041] The method of the present invention allows a first spinal mill to be morphologically connected to the bone structure to be operated on, and so on, to have sufficient retention for further surgery on the same bone structure, while a subsequent spinal mill can be removed from the surgical site. Preferably, the spinal mill is introduced into the surgical site along a drill, guide wire and / or guide sleeve.

[0042] In another embodiment of the method of the present invention, the placement of the guide means at the surgical site is performed via access to the surgical site, which is formed by access means. The access means may include, for example, a drill or needle, particularly a Jamsity needle. The formation of the access is performed on an X-ray basis and / or by navigation, i.e., using navigation means and / or robotically. The surgical site may be the articular process region of the vertebrae, particularly the superior articular process region of the vertebrae. The needle may be cannulated, i.e., having an internal space within which the guide means can be placed at the surgical site, and in particular, connectable to the bone structure at the surgical site. During surgery on the bone structure at the surgical site, the vertebral mill, particularly its distal end face and / or threaded portion, may be surrounded by a protective working sleeve.

[0043] Preferably, the guidance of the spinal mill is improved if the guiding means is connected to and, in particular, fixed to the bone structure before the spinal mill is introduced into the surgical site.

[0044] Preferably, before introducing the spinal mill to the surgical site, particularly after the guide means and the bone structure have been connected, a protective sleeve (also called a working sleeve) can be advanced through the guide means, particularly through the first spinal mill, to the surgical site, thereby protecting sensitive tissues at the surgical site, especially nerve structures.

[0045] Preferably, surgery on the bone structure using the first vertebral flap is performed primarily on its outer surface, so that the bone structure is mainly operated on laterally, i.e., along the periphery of the vertebral flap, thereby protecting sensitive structures such as nerves. In particular, this allows for better protection of sensitive nerve structures located distal to the vertebral flap.

[0046] Preferably, access to the surgical site is made via the articular processes of the vertebral bodies, particularly the articular processes facing upward. This method is configured such that access to the spinal canal, or further to the intervertebral disc space of the vertebra, particularly its gelatinous nucleus (nucleus pulposus), is formed by surgery on the bone structure, especially the bone structure in the articular region of the vertebral bodies. After the spinal milling is removed from the surgical site, in an improved form of this method, a working sleeve is introduced into the intervertebral disc space through the access formed by the spinal milling, and the gelatinous nucleus of the intervertebral disc space can then be removed therein, particularly endoscopically. In this sense, this method is used as part of the implantation of an intervertebral implant (also called an intervertebral basket or intervertebral cage).

[0047] Further advantages and features of the present invention will become apparent from the claims and subsequent description, and embodiments of the present invention will be described in detail below with reference to the drawings. [Brief explanation of the drawing]

[0048] [Figure 1] A perspective view of the spinal milling machine according to the present invention. [Figure 2] Side view of the spinal milling machine shown in Figure 1. [Figure 3] A perspective view of another spinal milling machine, particularly a spinal milling machine as part of the spinal milling system according to the present invention. [Figure 4] Enlarged view of circular section G in Figure 3. [Figure 5] Side view of the spinal milling machine shown in Figure 3. [Figure 6] Perspective view of the spinal milling system. [Figure 7] Enlarged view of circular section C in Figure 6. [Figure 8] Figure 6 shows a perspective view of the spinal milling system from another angle. [Figure 9] Enlarged view of circular section H in Figure 8. [Figure 10] Figure 6 shows a side view of the spinal milling system. [Figure 11]A perspective view of the spinal milling system in Figure 6, with another spinal milling machine fully inserted. [Figure 12] Enlarged view of circular section B in Figure 11. [Figure 13] Enlarged view of circular section A in Figure 11. [Figure 14] A side view of the distal end face shown in Figure 13. [Figure 15] A further enlarged view of the distal end face of the circular portion A in Figure 11. [Figure 16] A side view of the distal end face shown in Figure 15. [Figure 17] A further enlarged view of the distal end face of the circular portion A in Figure 11. [Figure 18] A side view of the distal end face shown in Figure 17. [Figure 19] Side view of the spinal milling system shown in Figure 11. [Figure 20] A flowchart illustrating an example of the method according to the present invention. [Figure 21] A flowchart illustrating an example of the method according to the present invention. [Figure 22] A flowchart illustrating an example of the method according to the present invention. [Figure 23] A flowchart illustrating an example of the method according to the present invention. [Figure 24] A flowchart illustrating an example of the method according to the present invention. [Figure 25] A flowchart illustrating an example of the method according to the present invention. [Figure 26] A flowchart illustrating an example of the method according to the present invention. [Figure 27] A flowchart illustrating an example of the method according to the present invention. [Figure 28] A flowchart illustrating an example of the method according to the present invention. [Figure 29] A flowchart illustrating an example of the method according to the present invention. [Figure 30] A flowchart illustrating an example of the method according to the present invention. [Figure 31] A flowchart illustrating an example of the method according to the present invention. [Figure 32] A flowchart illustrating an example of the method according to the present invention. [Figure 33] A flowchart illustrating an example of the method according to the present invention. [Figure 34] A flowchart illustrating an example of another method according to the present invention. [Figure 35] A flowchart illustrating an example of another method according to the present invention. [Figure 36] A flowchart illustrating an example of another method according to the present invention. [Figure 37] A flowchart illustrating an example of another method according to the present invention. [Figure 38] A flowchart illustrating an example of another method according to the present invention. [Figure 39] A flowchart illustrating an example of another method according to the present invention. [Figure 40] A flowchart illustrating an example of another method according to the present invention. [Figure 41] A flowchart illustrating an example of another method according to the present invention. [Figure 42] A flowchart illustrating an example of another method according to the present invention. [Figure 43] A flowchart illustrating an example of another method according to the present invention. [Figure 44] A flowchart illustrating an example of another method according to the present invention. [Figure 45] A flowchart illustrating an example of another method according to the present invention. [Modes for carrying out the invention]

[0049] Figure 1 shows a perspective view of the spinal milling machine 10 according to the present invention for surgically treating bone structures in the spinal region at the surgical site. The spinal milling machine 10 has a working length of 235 mm and an outer diameter of approximately 7.3 mm.

[0050] At the distal end face 11, the spinal milling machine 10 has a convex rounded portion 12, also known as a trauma-reducing rounded portion, which avoids the risk of unintentional damage to nerves or soft tissue structures surrounding the surgical site when operating on bone structures. A through-hole 14 extends from the distal end face 11 to the proximal end face 13 of the spinal milling machine 10, i.e., its entire axial length of approximately 278 mm, and this through-hole 14 is configured to accommodate another spinal milling machine 15, which is not shown in Figure 1. The through-hole 14 has a circular cross-section and a diameter of approximately 4.1 mm.

[0051] To surgically cut bone structures, the distal end face 11 of the vertebral milling machine 10 has milling teeth 16, which are equipped with a tooth profile 17. In the embodiment shown in Figure 1, the distal end face 11 has a plurality of radially outward-facing teeth 18 distributed circumferentially on its radially outer side. As is particularly clear from the enlarged view in Figure 13, each tooth 18 of the tooth profile 17 has two ridges 19 and 20 of different radial heights, with a stepped transition 21 formed between these ridges 19 and 20. When viewing the distal end face 11 from the distal side, the first ridge 19 has a greater radial height than the second ridge 20 of the same tooth 18. The left side surface 22 corresponding to the first ridge 19 has a larger inclination angle than the right side surface 23 corresponding to the second ridge 20. The outer circumference of the teeth 18 corresponding to the tooth profile 17 is formed as a cutting edge. Between two adjacent teeth 18, a parabolic recess 24 is formed in the circumferential direction, which connects the right side surface 23 of one tooth 18 to the left side surface 22 of the next tooth 18 without any step.

[0052] The tooth profile 17 of the distal end face 11 extends proximal, and as a result, as shown in Figure 1, the outer peripheral surface 25 on the proximal side of the distal end face 11 of the spine milling cutter 10 has a threaded portion 26. Therefore, the outer peripheral shape 27 of the cross-section of the threaded portion 26 at a certain axial position corresponds to the tooth profile 17 of the distal end face 11, and in particular, it is rotated by a certain angle with respect to this tooth profile 17, around the extending axis of the spine milling cutter 10. The threaded portion 26 has an axial length of approximately 60 mm and a helix angle of 80°, and the proximal end 28 of the threaded portion 26 transitions to a substantially smooth outer peripheral surface 25 without any steps.

[0053] On the proximal side of the threaded portion 26, the spine milling cutter 10 has a connecting portion 32 at its proximal end 31. This connecting portion 32 is configured to accommodate another spine milling cutter 15, and is particularly configured for a detachable and shape-fitting connection with another spine milling cutter 15, which will be described later. The connecting portion 32 has a basic triangular shape with rounded corners 33, and in this embodiment functions as a connecting body, rotating the spine milling cutter 10 according to the present invention in synchronization with the other spine milling cutter 15. Figure 2 is a side view of the spine milling cutter according to the present invention shown in Figure 1, and from this figure the axial length of the entire spine milling cutter 10 and the length of the threaded portion 26 are clearly shown.

[0054] Figure 3 shows another spine milling cutter 15, which, together with the spine milling cutter 10 according to the present invention in the embodiment of Figure 1, for example, forms the spine milling cutter system 34 according to the present invention shown in Figure 6. The other spine milling cutter 15 has a working length of approximately 255 mm and an outer diameter of approximately 4 mm, with a total length of approximately 278 mm, so that the outer diameter substantially matches the inner diameter of the axial through hole 14 of the spine milling cutter 10 according to the present invention. Only a relatively small gap is formed at most to ensure the mobility of the other spine milling cutter 15 within the axial through hole 14 of the spine milling cutter 10 according to the present invention. Thus, the second spine milling cutter 15 can be accommodated within the axial through hole 14 of the first spine milling cutter 10 according to the present invention.

[0055] The distal end face 35 of the second spinal milling cutter 15 has a concave rounded portion 36, unlike the convex rounded portion 12 of the first spinal milling cutter 10 (Figure 1), as shown in the enlarged view of Figure 4. Milling teeth 38 with a tooth profile are arranged on the peripheral contour 37 of the distal end face 35, and these teeth consist of five teeth 40. Each tooth 40 is oriented distally in the axial direction and outward in the radial direction. As is clear from the enlarged view of the tooth profile 39 in Figure 4, the teeth 40 are not symmetrically configured. Each tooth 40 has two ridges 41 and 42 of different heights in the radial direction, and unlike the tooth profile 17 of the first spinal milling cutter 10 shown in Figure 1, the first left side surface 43 of the tooth 40 has an inclination of approximately 90°, while the second right side surface 44 has an inclination of approximately 40°. A substantially stepless transition zone 45 is formed between the radial ridges of the teeth, and similarly, a stepless transition zone is formed between two adjacent teeth 40.

[0056] Similar to the first spinal milling cutter 10, the tooth profile 39 of the second spinal milling cutter 15 extends proximal, resulting in a threaded portion 47 on the outer circumferential surface 46 of the second spinal milling cutter 15. The threaded portion 47 of the second spinal milling cutter 15 has an axial length of 20 mm and a twist angle of 80°, which is also shown in the side view of the second spinal milling cutter 15 shown in Figure 5. The axial length of the threaded portion 47 of the second spinal milling cutter 15 is shorter than the axial length of the threaded portion 26 of the first spinal milling cutter 10.

[0057] At the proximal end 49, the second spinal milling cutter 15 has a connecting portion 50 comprising a proximal connecting portion 51 and a distal connecting portion 52. The distal connecting portion 52 is configured such that its outer contour 53 corresponds to the inner contour 54 of the connecting portion 32 of the first spinal milling cutter 10 shown in Figures 8 and 9. Thus, the second spinal milling cutter 15 is pushed in through the axial through hole 14 of the first spinal milling cutter 10 from the proximal side and is movable until the distal connecting portion 52 of the second spinal milling cutter 15 is fully accommodated in the connecting portion 32 of the first spinal milling cutter 10. In this state, the second spinal milling cutter 15 can be connected to the first spinal milling cutter 10 in a shape-fitting manner, and in this state, the first spinal milling cutter 10 can rotate in sync with the second spinal milling cutter 15 when it is rotationally driven. As already mentioned, since the outer contour 53 of the distal connection portion 52 of the second vertebral milling machine 15 corresponds to the inner contour 54 of the connection portion 32 of the first vertebral milling machine 10, when the two vertebral milling machines 10 and 15 are connected, a seamless transition is formed between the proximal connection portion 51 of the second vertebral milling machine 15 and the connection portion 32 of the first vertebral milling machine 10. This is also shown in Figures 11 and 12.

[0058] To drive the second spinal milling machine 15, a drive device (not shown) is connected to the proximal connection 51, which can rotate it. Since it is connected to the first spinal milling machine 10 by shape fitting, the first spinal milling machine 10 is also rotated in synchronously with the second spinal milling machine 15. To disconnect, the second spinal milling machine 15 is moved proximal to the first spinal milling machine 10 and pushed out from the first spinal milling machine 10. As shown in Figures 3 and 4, the second spinal milling machine 15 has an axial through-hole 55 with a diameter of approximately 2.4 mm, and this through-hole 55 is configured to accommodate a guide wire 69, a drill 64, or a guide rod 70 that is guided to the surgical site as a guide means 65.

[0059] Figure 6 is a perspective view of the spinal milling system 34 according to the present invention, which comprises a first spinal milling cutter 10 and a second spinal milling cutter 15, viewed obliquely from the distal side. The second spinal milling cutter 15 is inserted from the proximal side and is only partially inserted into the axial through hole 14 of the first spinal milling cutter 10. The distal end face 35 of the second (inner) spinal milling cutter 15 is not shown in Figure 6 because, at this position, it does not protrude beyond the distal end face 11 of the first (outer) spinal milling cutter 10, but is rather covered by the first spinal milling cutter 10. According to Figure 7 (an enlarged view of the circular part C in Figure 6), the proximal connecting portion 32 of the first spinal milling cutter 10 is configured to accommodate the distal connecting portion 52 of the connecting portion 50 of the second spinal milling cutter 15.

[0060] Figure 8 shows the spinal milling system 34 according to Figure 6 in another perspective view, that is, a view from the proximal side, which in particular shows the axial through hole 14 and the inner contour 54 of the connection portion 32 of the first spinal milling machine 10, which, as already mentioned, is configured to receive the distal connection portion 52 of the second spinal milling machine 15 in a shape-engagement manner. Next to this, the axial through hole 55 of the second spinal milling machine 15 can be seen, which is concentric with the axial through hole of the first spinal milling machine 10. This is also evident from the enlarged view of the circular portion H in Figure 8, which is shown in Figure 9. Figure 10 shows the spinal milling system 34 according to Figures 6 and 8 in a side view.

[0061] Figure 11 shows a perspective view from an oblique distal direction of the second spinal milling cutter 15 fully inserted into the first spinal milling cutter 10. The second spinal milling cutter 15, particularly its distal end face 35, protrudes approximately 4 mm from the distal end face 11 of the first spinal milling cutter 10, so that the milling teeth 38 and threaded portion 47 of the second spinal milling cutter 15 are clearly visible. Figure 12 shows a magnified view of the proximal ends 31 and 49 of both spinal milling cutters 10 and 15 in Figure 11. The distal connection 52 of the connection 50 of the second spinal milling cutter 15 is fully housed within the connection 32 of the first spinal milling cutter 10 and is therefore covered in Figure 12. A flush transition is formed between the proximal connection 51 of the second spinal milling cutter 15 and the connection 32 of the first spinal milling cutter 10. When the second spine milling cutter 15 is driven by a drive mechanism (not shown), the first spine milling cutter 10 rotates in sync with it, and the connection portion 32 of the first spine milling cutter 10 acts as a clutch to establish synchronization of the rotational motion of the spine milling cutters 10 and 15. The total length of the spine milling cutter system 34 is 278 mm, which is approximately equivalent to the axial length of the second spine milling cutter 15.

[0062] Figure 13 is an enlarged view of the circular part A in Figure 11, showing the distal end faces 11, 35 and their threaded portions 26, 47 of both vertebral milling cutters 10, 15. As already described, the second vertebral milling cutter 15 protrudes approximately 4 mm axially from the distal end face 11 of the first vertebral milling cutter 10. The rounding 12, 36 of the end faces 11, 35 of both vertebral milling cutters 10, 15, as well as their tooth profiles 17, 39 and threaded portions 26, 47, are clearly visible. Since the outer diameter of the outer circumferential surface 46 of the second vertebral milling cutter 15 is approximately equal to the diameter of the axial through hole 14 of the first vertebral milling cutter 10, only a relatively narrow gap is formed between the vertebral milling cutters 10, 15. Figure 14 shows a side view of Figure 13, from which it is clear that the lead angle and rotation direction of the threaded portion 47 of the second spinal milling cutter 15 are in fact similar to the lead angle and rotation direction of the threaded portion 26 of the first spinal milling cutter 10.

[0063] Figure 15 shows another embodiment of the distal end face 11 and threaded portion 26 of the first spine milling cutter 10, in which the tooth profile 17 of the distal end face 11 has teeth 18 distributed around the distal end face 11 and radially outward from the distal end face 11, but the teeth 18 are oriented distally, improving the cutting characteristics of the distal end face 11 of the first spine milling cutter 10. The teeth 18 of the tooth profile 17 have a nearly right-angled side surface 22 on the left side and a right side surface 23 with a lead angle of about 40° when viewed clockwise from a distal viewpoint, and there is a recess 24 with a stepless transition between two adjacent teeth 18. The tooth profile 17 extends proximal, and a threaded portion 26 is formed in the embodiment of Figure 15 as well, following the embodiment of Figure 13, which is done via a stepless transition region 56 that is longer in the axial direction. This is also evident from the side view of Figure 16. The spinal milling system 34 shown there has the same second spinal milling machine 15 as in Figure 13, which also protrudes approximately 4 mm in the axial direction from the distal end face 11 of the first spinal milling machine 10.

[0064] Figure 17 shows another embodiment of the distal end face 11 of the first spine milling cutter 10, which, similar to the embodiment in Figure 13, has a tooth profile 17 with radially outward-facing teeth 18, which, as already mentioned, transition to a threaded portion 16 in the proximal extension. In contrast to the embodiment in Figure 13, the distal end face 11 has a distal projection 57 with an additional tooth profile 58, which largely follows the embodiment in Figure 15 and has teeth 59 in particular that are distally oriented. Thus, the embodiment in Figure 17 combines the cutting capability of radially outward-facing teeth 18 in the embodiment in Figure 13 with the cutting capability of distally oriented teeth 18 in the embodiment in Figure 15. Similar to the embodiment in Figure 15, the second spine milling cutter 15 protrudes approximately 4 mm distally from the distal end face 11 of the first spine milling cutter 10, which is also evident from the side view in Figure 18.

[0065] Figure 19 shows a side view of the spinal milling system 34 of Figure 11, where the circular portion B shown therein is the same as that shown in Figures 14, 16, and 18 in the three embodiments already described.

[0066] Figures 20 to 33 specifically illustrate the progress of the process according to the present invention, in which the bone structure 29 in the region of the spine 30 is treated at the surgical site 48, in particular using the spinal milling machine 10 according to the present invention.

[0067] Figure 20 shows a schematic diagram of the vertebrae 30 arranged almost horizontally, with the bone structure 29 of the upward-facing articular process 60 of the vertebral body 61 corresponding to the surgical site 48. Figure 21 shows the surgical site 29 as an enlarged view of circular area A in Figure 20. First, the Jamsity needle 62 shown in Figures 20 and 21 is driven towards the surgical site 48 on the upward-facing articular process 60 (processus articulares superior) by a trocar 63 that passes through its interior.

[0068] In the process from Figure 20 to Figure 22, the trocar 63, which has passed through the JamCity needle 62, is withdrawn proximal to the JamCity needle 62. The JamCity needle 62 remains in the surgical site 48. Figure 23 is an enlarged view of the circular area G in Figure 22, showing the JamCity needle 62 positioned at the surgical site 48. In the spirit of the present invention, the JamCity needle 62 functions as an access means in this process, providing access to the surgical site 48 for other instruments used to operate on the bone structure 29 through its interior.

[0069] In the process from Figure 22 to Figure 24, the drill bit 64 is guided to the surgical site 48 by passing through the hollow portion of the Jamsity needle 62 from distal to proximal. Subsequently, the drill bit 64 is driven into the upward-facing articular process 60 and connects with this articular process 60. This is shown in Figure 25 as an enlarged view of the circular part B in Figure 24. In this process, the drill bit 64 functions as a guide means 65 and serves as a guide for introducing the spinal milling machine 10 according to the present invention, which will be described later.

[0070] In the process from Figure 24 to Figure 26, the Jam City needle 62, which serves as an access means, is withdrawn proximal to the surgical site 48, but the cone 64, which serves as a guide means 65, remains in the surgical site 48, where it remains connected to the articular process 60. Figure 27 shows an enlarged view of the circular part C in Figure 26.

[0071] In the process from Figure 26 to Figure 28, a working sleeve 66 with a long lip 67 positioned on the right side of Figure 28, and a first spinal milling machine 10 and another second spinal milling machine 15 according to the present invention are advanced distally over a cone 64 toward the surgical site 48. These components are part of a spinal milling system 34. The working sleeve 66 radially surrounds the first spinal milling machine 10 according to the present invention, and the first spinal milling machine 10 further radially surrounds the other second spinal milling machine 15. From the positional relationship between the connection portion 32 of the first spinal milling machine 10 and the handpiece 50 of the second spinal milling machine 15 in Figure 28, it can be seen that the spinal milling machines 10 and 15 are rotatably and fixedly connected. Both vertebral mills 10 and 15 are rotationally driven, and as a result, the bone structure 29 is operated on at the surgical site 48, first by the second vertebral mill 15 which protrudes distally to the first vertebral mill 10, and finally by the first vertebral mill 10. During this operation, the cone 64 remains connected to the articular process 60. This is also shown in Figure 29 as an enlarged view of the circular part D in Figure 28.

[0072] After the first vertebral milling tool 10 is firmly held within the bone structure 29, the drill bit 64 is removed proximal to the surgical site 48 in the process from Figure 28 to Figure 30. The working sleeve 66 remains at the surgical site along with the vertebral milling tools 10 and 15. This is shown in Figure 31 as an enlarged view of the circular area E in Figure 30.

[0073] Subsequently, as an optional step, a blunt drill, guide wire, or guide rod can be moved distally through the axial through-hole 55 of the second vertebral mill 15 to the surgical site 48. Further surgery on the bone structure 29 may then be performed by the two vertebral mills 10, 15, which are not shown in the figure.

[0074] In the process from Figure 30 to Figure 32, the second vertebral milling machine 15 is moved proximal to the first vertebral milling machine 10, first withdrawn from the surgical site 48, and finally completely detached from the first vertebral milling machine 10. As a result, only the first vertebral milling machine 10 remains at the surgical site 48, housed in the working sleeve 66. Subsequently, the bone structure 29 is operated on solely by the first vertebral milling machine 10, through the working sleeve 66 which protects it from the surroundings. This situation is also shown in Figure 33 as an enlarged view of the circular area F in Figure 32.

[0075] Figures 34 to 45 illustrate another embodiment of the method according to the present invention. Figure 34 shows the surgical site 48, similar to Figure 20. Here, a hollow needle 68 is in contact with the bone structure 29, and this hollow needle 68 can also be called an access needle as an access means. The hollow needle 68 has been pre-inserted into the surgical site 48 using a stiletto, which is not shown in Figure 34. Figure 35 is an enlarged view of the circular area H in Figure 34, showing how the hollow needle 68 is positioned on the bone structure 29.

[0076] In the process from Figure 34 to Figure 36, after the stiletto is removed, the guidewire 69 is guided from proximal to distal through the hollow needle 68 to the bone structure 29 of the surgical site 48. This is also evident from Figure 37, which is an enlarged view of the circular area I of Figure 36. In the process from Figure 36 to Figure 38, the hollow needle 68 is removed proximal to the surgical site 48, leaving only the guidewire 69. This is also shown in Figure 39, which is an enlarged view of the circular area J of Figure 38. Subsequently, in the process from Figure 38 to Figure 40, the guide rod 70 is moved distally over the guidewire 69 to the surgical site 48. Figure 41 shows an enlarged view of the circular area K of Figure 40.

[0077] In the process from Figure 40 to Figure 42, similar to Figure 28, the working sleeve 66, including the extended lip 67, along with the spinal milling machines 10 and 15 housed inside it, is pushed distally along the guide rod 70 toward the surgical site 48. Figure 41 shows an enlarged view of the circular part L in Figure 40.

[0078] In the process from Figure 42 to Figure 44, as already described in relation to the first embodiment of the process of the present invention, the two vertebral milling machines 10 and 15 are rotated to operate on the bone structure 29 at the surgical site 48. This continues until the first vertebral milling machine 10 has achieved sufficient retention within the bone structure 29. Figure 45 shows an enlarged view of the circle M in Figure 44. After the first vertebral milling machine 10 has achieved firm retention within the bone structure 29, the second vertebral milling machine 15 is removed proximal to the surgical site 48. As a result, further surgery on the bone structure 29 is performed only by the first vertebral milling machine 10, which is protected by the working sleeve 66, and finally, the first vertebral milling machine 10 is also removed from the surgical site 48. [Explanation of Symbols]

[0079] 10 First vertebral flap 11 Distal end face 12. Rounded part 15. Second vertebral flap 16 milling teeth 17 Tooth marks 18 teeth

Claims

1. A spinal milling machine (10) for surgically altering bone structures (29) in the region of the spine (30), It comprises a distal end face (11) having milling teeth (16) with a tooth profile (17) having at least two teeth (18), It further has an axial through-hole (14) for accommodating another spinal mill (15), Spinal milling machine.

2. The spinal milling cutter according to claim 1, characterized in that the tooth profile (17) is at least partially configured as a cutting edge.

3. The spinal milling machine according to claim 1 or 2, characterized in that the distal end face (14) of the spinal milling machine (10) has a rounded portion (12) that is particularly convex.

4. The spinal milling machine according to any one of claims 1 to 3, characterized in that at least one tooth (18) of the tooth profile (17) is oriented distally and / or radially.

5. The spinal milling machine according to claim 4, characterized in that at least one tooth (18) of the tooth profile (17) is not configured to be mirror-symmetric, and the tooth (18) comprises two radial ridges (19, 20) having particularly different radial heights, and in particular a stepped transition portion (21) is formed between the radial ridges (19, 20) of the tooth (18).

6. The spinal milling machine according to any one of claims 1 to 5, characterized in that at least one tooth (18) of the tooth profile (17) has a first side surface (22) and a second side surface (23), and the slope of the first side surface (22) is greater than the slope of the second side surface (23).

7. The spinal milling machine according to any one of claims 1 to 6, characterized in that two adjacent teeth (18) of the tooth profile (17) are separated from each other by a parabolic recess (24).

8. The spine milling cutter according to any one of claims 1 to 7, characterized in that the spine milling cutter (10) has a threaded portion (26) on the proximal side of the milling cutter tooth profile (17).

9. The spinal milling cutter according to claim 8, characterized in that the threaded portion (26) is formed by the tooth profile (17) extending proximal.

10. The spinal milling machine according to claim 8 or 9, characterized in that the threaded portion (26) has an axial length of 10 mm to 90 mm, preferably 20 mm to 75 mm, and most preferably about 60 mm.

11. The spine milling machine according to any one of claims 8 to 10, characterized in that the threaded portion (26) has a thread taper of 60° to 85°, particularly 70° to 85°, most preferably 75° to 80°, for example 75° or 80°.

12. The spinal milling machine according to any one of claims 1 to 11, characterized in that the tooth profile (17) has at least one triangular basic shape tooth (18).

13. The spinal milling machine according to any one of claims 1 to 12, characterized in that the distal end face (11) of the spinal milling machine (10) has a distal projection (57), and the projection (57) is particularly provided with another tooth profile (58).

14. The spinal milling machine according to claim 13, characterized in that the tooth profile (58) of the projection (57) is configured to be mirror-image symmetric, and in particular, the tooth profile (58) of the projection (57) each has a triangular base-shaped tooth (59).

15. The spinal milling machine according to any one of claims 1 to 14, characterized in that the proximal end (31) of the spinal milling machine (10) has a connecting portion (32) configured to accommodate another spinal milling machine (15).

16. A first spinal milling machine (10) and a second spinal milling machine (15) according to any one of claims 1 to 15, A spinal milling system (34) wherein the second spinal milling cutter (15) can be housed in an axial through hole (14) of the first spinal milling cutter (10), and the distal end face (35) is equipped with milling teeth (38) having a tooth profile (39).

17. The spinal milling system according to claim 16, characterized in that the second spinal milling machine (15) is connected to the first spinal milling machine (10) in a way that prevents rotation and / or allows for detachment.

18. The spinal milling system according to claim 16 or 17, characterized in that the second spinal milling machine (15) is configured according to any one of claims 1 to 15.

19. The spinal milling system according to any one of claims 16 to 18, characterized in that the second spinal milling machine (15) has a proximal connecting portion (50), and the outer shape (53) of the connecting portion (50) is configured to be at least partially complementary to the inner shape (54) of the connecting portion (32) of the first spinal milling machine (10).

20. The spinal milling system according to any one of claims 16 to 19, characterized in that it is provided with a drive unit configured to rotationally drive the first spinal milling machine (10) and / or the second spinal milling machine (15).

21. The spinal milling system according to any one of claims 16 to 20, characterized in that the spinal milling machines (10, 15) are rotatable independently of each other.

22. The spine milling system according to any one of claims 16 to 21, characterized in that the second spine milling cutter (15) has an axial through hole (55), and the through hole (55) is concentric with the axial through hole (14) of the first spine milling cutter (10), particularly when coupled with the first spine milling cutter (10).

23. The spinal milling system according to any one of claims 16 to 22, characterized in that at least one tooth (40) of the tooth profile (39) of the second spinal milling machine (15) has a triangular basic shape.

24. The spinal milling system according to any one of claims 16 to 23, characterized in that the tooth profile (39) of the second spinal milling cutter (15) extends proximal to form a threaded portion (47) of the second spinal milling cutter.

25. The spinal milling system according to any one of claims 16 to 24, characterized in that the second spinal milling cutter (15) is housed in the axial through hole (14) of the first spinal milling cutter (10) and / or connected to the first spinal milling cutter (10).

26. A method for surgically treating a bone structure (29) in the region of the spine (30) at a surgical site (48) using a first spinal milling machine (10) according to any one of claims 1 to 15, and more particularly a spinal milling system (34) according to any one of claims 16 to 25, - A step of inserting the first spinal milling machine (10) into the surgical site (48) along a guide means (65), together with another spinal milling machine (15) housed in its axial through-hole (14), wherein the guide means (65) is positioned within the axial through-hole (14) of the first spinal milling machine (10), and particularly within the axial through-hole (55) of the other spinal milling machine (15), - A step of rotating the first spinal milling machine (10) together with another spinal milling machine (15) so that the bone structure (29) of the surgical site (48) is operated on along a predetermined path, - The step of removing the other spinal mitre (15) from the surgical site (48), - A step of rotating the first spinal milling machine (10) so that surgery on the desired bone structure (29) can be performed at the surgical site (48), - The step of removing the first spinal stenosis (10) from the surgical site (48), A surgical method for reducing the size of the body.

27. The method according to 26, characterized in that the guide means (65) is connected to the bone structure (29) before the spinal milling machine (10, 15) is inserted into the surgical site (48).

28. The method according to 26 or 27, characterized in that, before inserting the spinal mills (10, 15) into the surgical site (48), particularly after the guide means (35) has been connected to the bone structure (29), the protective sleeve (66) is pushed into the surgical site (48) along the guide means (35), particularly the first spinal mills (10).

29. The method according to any one of claims 26 to 28, characterized in that the surgery on the bone structure (29) is substantially performed by the outer surface (25) of the first vertebral mill (10).

30. The method according to any one of claims 26 to 29, characterized in that access to the surgical site (48) is made via the articular process (60) of the vertebral body (61), particularly the articular process (60) directed upward of the vertebral body (61).

Images