Medical cutting instrument for tissue and instrument set of a surgical procedure

Abstract

The invention relates to a medical cutting instrument for tissue for use in surgical, in particular endoscopic, procedures on the spinal column. The cutting instrument has a substantially axially extending main body and a blade which is connected to the main body in a distal region and which has a distally oriented cutting edge. The blade projects distally from the main body. The cutting instrument has an axial lumen extending over the entire length of the cutting instrument. The invention additionally relates to an instrument set comprising the cutting instrument and to a method for a surgical procedure using the cutting instrument.

Description

[0001] MEDICAL TISSUE CUTTING INSTRUMENT AND SURGICAL INSTRUMENT SET

[0002] The invention relates to a medical cutting instrument for tissue for use in surgical, in particular endoscopic, procedures on the spine, comprising a substantially axially extending base body and a blade connected to the base body in a distal region and having a distally oriented cutting edge, the blade projecting distally beyond the base body. The invention also relates to a medical instrument set and a method for an endoscopic procedure on the spine.

[0003] When performing spinal surgery, it is common practice to first guide a guide wire with a relatively small diameter to the surgical site before inserting the actual surgical instrument. This ensures that the instruments used in the procedure can reliably reach the surgical site. Before further instruments can be advanced over the guide wire to the surgical site, also known as the insertion site, a tissue incision is typically made on the patient's skin surface in an area surrounding the guide wire using a scalpel guided freely by the surgeon. The other instruments used in the procedure are then advanced through this incision to the insertion site.A disadvantage of this method is that the manual, free execution of the tissue incision means its position relative to the guide wire is subject to fluctuations. This also applies to the length of the tissue incision. In particular, it cannot be ruled out that tissue may still be present between the tissue incision and the guide wire, which complicates the insertion of further instruments and can lead to tissue trauma.

[0004] The object of the invention is therefore to eliminate the aforementioned disadvantages and to develop a medical cutting instrument with which tissue cutting can be carried out in a more reliable manner.

[0005] The object of the invention is achieved with a medical cutting instrument according to claim 1, characterized in that the cutting instrument has an axial lumen extending over the entire length of the cutting instrument.

[0006] The object of the invention is further achieved by an instrument set according to claim 22, comprising a cutting instrument according to the invention and at least one of the following instruments: needle, in particular hollow needle, preferably with stylet inserted therein, guide wire, awl, drill, milling cutter, dilator, working sleeve, working instrument, endoscope.

[0007] Furthermore, the object of the invention is achieved by a method of performing a surgical procedure on the spine at a surgical site using the cutting instrument according to the invention, in particular the instrument set according to the invention, in the following steps:

[0008] Creating access to the intervention site via a hollow needle, in particular with a stylet inserted therein; inserting a guide wire to the intervention site; inserting the medical cutting instrument distally over the guide wire to a tissue of the patient to be treated; moving the medical cutting instrument distally along the guide wire in such a way that the blade of the medical cutting instrument treats the tissue, whereby the medical cutting instrument is guided further distally and, in particular, the treated tissue spreads due to the geometry of the medical cutting instrument; inserting a working sleeve over the cutting instrument to the intervention site; removing the cutting instrument proximally; inserting a working instrument and / or an endoscope to the intervention site and treating the intervention site.

[0009] A fundamental aspect of the invention, particularly in contrast to known manually and freely guided scalpels, is to further develop the cutting instrument by means of the lumen in such a way that the guide wire, which is usually already positioned during the procedure on the spine, can be used to guide the cutting instrument in such a way that the tissue incision can be performed reliably and reproducibly with the cutting instrument according to the invention. In particular, this makes it possible to perform the tissue incision as close as possible to the access point where the guide wire is located. This avoids leaving as little tissue as possible between the access point and the tissue incision, which improves the safety and reliability of the tissue incision and the endoscopic procedure overall.In particular, when, during endoscopic intervention using the known Seldinger technique, a needle is first guided to the intervention site, and the guide wire is positioned through the needle at the intervention site, the guide wire can be used to guide the cutting instrument in order to make the tissue incision as close as possible to the access point. In this respect, the cutting instrument according to the invention can be inserted directly over the already positioned guide wire. This also represents an improvement in efficiency by utilizing the instruments already present during the procedure.

[0010] For the purposes of the invention, the access point is the position at which the guide wire penetrates the patient's tissue, for example, the skin surface or tissue distal to it. The lumen of the base body is therefore specifically designed to receive the guide wire. For the purposes of the invention, lumen refers to an opening, particularly one that is circular in cross-section, extending over the entire axial length of the base body. The cutting edge of the blade refers to the area designed to perform the tissue incision.

[0011] In accordance with the invention, a proximal direction points towards the operator, while a distal direction is oriented opposite to the proximal direction and points towards the insertion site. An axial direction points from proximal to distal or vice versa. In the sense of a three-dimensional cylindrical coordinate system, a radial direction and a circumferential direction are each perpendicular to the axial direction and perpendicular to each other. Preferably, the lumen is arranged radially centered relative to the cross-section of the base body. The base body can have a circular cross-section, at least in some areas. In a further embodiment of the invention, the lumen itself can have a circular cross-section, wherein the lumen is provided, in particular, with a diameter between 0.5 mm and 3 mm, preferably 1 mm.

[0012] The blade may have a distal tip to provide a defined entry point for the tissue incision. The position of the distal tip also indicates the entry point to the surgeon, allowing for easy control of the procedure. The distal tip may be at least 5 mm, preferably at least 15 mm, away from the distal end face of the blade body.

[0013] In a further development of the invention, the blade, in particular the distal blade tip, can be arranged radially eccentrically to the lumen of the base body in order to make the tissue incision adjacent to the guide wire, which is received in the lumen of the base body during insertion. The radial distance of the blade tip to the lumen of the base body can be chosen to be as small as possible in order to make the desired tissue incision as close as possible to the lumen. The radial distance of the blade tip to the lumen of the base body can be a maximum of 2.5 mm. The blade can be aligned parallel to the lumen of the base body in order to make the tissue incision parallel to the direction of the guide wire.Preferably, the cutting edge of the blade defines a blade plane, wherein the distal blade tip is encompassed by a plane arranged perpendicular to the blade plane and at the level of the lumen of the base body, i.e., passing through the lumen of the base body. Thus, the distal blade tip lies in the projection of the lumen onto the blade plane, so that the insertion point is centered relative to the blade plane in order to make the tissue incision as close as possible to the access point, thereby facilitating the relatively easy insertion of further instruments during the procedure.

[0014] The cutting edge of the blade can extend from the distal blade tip proximally to a first outer blade corner, in particular to a first outer blade tip, so that, with continued distal movement of the cutting instrument, the tissue incision is first made by means of the distal blade corner, in particular the distal blade tip, and then successively widens along the cutting edge of the blade until the tissue incision reaches its greatest extent when the outer blade corner penetrates the patient's tissue. In particular, in a region between the distal blade tip and the outer blade corner, the cutting edge can be linear, and may be provided to have at least two linear sections. The cutting edge can have a concave curvature, particularly in this region.

[0015] The cutting edge of the blade can extend proximally from the distal tip to both sides of the blade, allowing the tissue incision to be made on either side of the distal tip. This enables a more efficient procedure, especially since conventional scalpels typically only cut in one direction. This necessitates removing the scalpel after the initial incision, rotating it 180° around its longitudinal axis, and then reapplying it to extend the existing incision in the opposite direction. By shaping the cutting edge as described above, this second cut becomes unnecessary, as the instrument cuts in both directions simultaneously. The cutting edge can therefore be arrow-shaped.

[0016] Preferably, the cutting edge extends from the distal blade tip proximally to a second outer blade tip, in particular a second outer blade corner, which is arranged, in particular, opposite the first outer blade tip, in particular the first outer blade corner. The advantages obtained in connection with the first outer blade corner can thus be achieved for both sides of the cutting edge. The axial distance of at least one, in particular both, outer blade corners to the base body can be at least 0 mm and / or a maximum of 2 mm, in particular a maximum of 4 mm.

[0017] Preferably, the at least one outer blade corner projects radially beyond the base body, particularly its largest diameter, by a radial distance of at least 0 mm, and more specifically, at least 2 mm. Since the length of the tissue cut is then greater than the diameter of the base body, it can penetrate and widen the tissue as easily as possible during continued distal movement of the cutting instrument. The blade can taper proximally from the at least one outer blade tip, particularly to the base body, and more specifically from both outer blade tips proximally. In this way, the at least one outer blade corner is formed as a blade tip. In a further development of the invention, the blade can be widened proximally from the distal blade tip to the base body, so that the blade has a triangular base shape.

[0018] At least one transition of the blade, in particular from its cutting edge, to the base body can be designed without edges in order to avoid tissue injuries, such as tissue contusions, in this area.

[0019] Preferably, the blade is designed to be at least partially mirror-symmetrical about a plane that is arranged centrally and perpendicular to the blade plane, in particular to the blade surface, and / or at the level of the lumen of the base body. The plane of symmetry can correspond to the perpendicular bisector of the blade plane. Particularly preferably, the blade is designed to be completely mirror-symmetrical. The blade can have a portion projecting distally beyond the base body with an axial length between 5 mm and 20 mm, in particular about 15 mm. The blade can have a width between 4 mm and 11 mm and / or a height between 0.2 mm and 0.7 mm, preferably about 0.4 mm.

[0020] The blade can be positively and / or force-fit connected to the base body. Preferably, the blade is bonded to the base body. The blade can be detachably and / or rotationally fixed to the base body.

[0021] The base body may have a slot, particularly axially oriented, on its distal end face, into which the blade is inserted and, in particular, bonded to the base body. This ensures both a secure hold of the blade and a predefined orientation of the blade relative to the base body. The distal end face of the base body may, particularly in the area of ​​the transition between the blade and the base body, have an atraumatic rounding to reduce the risk of trauma.

[0022] Preferably, the base of the instrument widens from the distal end face proximally, particularly conically. This allows the cutting instrument to be used directly for tissue dilation after the incision, thus accelerating the procedure overall. In this way, the medical cutting instrument can be considered a combination of a scalpel and a dilator.

[0023] The expansion of the base body from its distal end face proximally can vary in degree in the circumferential direction. In the area of ​​expansion, particularly in the distal end region, the base body may have a radial center in cross-section that is spaced away from the lumen, thus being eccentric to it. In this way, the extent of tissue dilation can be influenced by a correspondingly designed geometry of the base body, depending on the angular orientation. The base body may have a smaller cone angle in a region facing the blade than in a region facing away from the blade, so that the base body has a smaller slope in the region facing the blade than in the region facing away from the blade.This allows for greater tissue dilation on the side facing away from the blade during distal movement of the cutting instrument following the tissue incision. The instrument body may also feature a grip recess on the side facing away from the blade to improve the surgeon's handling of the cutting instrument.

[0024] Proximal to its distal end, the base body can have at least a partially cylindrical shape. In particular, the base body can have, for example, a concavely curved recess in the form of an annular groove around its entire circumference, which can serve as a fastening point for a protective cap associated with the base body, especially as a snap-in mechanism. A snap-in projection of the protective cap can engage in the annular groove to allow the protective cap to be connected to the base body in a predefined axial position, particularly in a detachable manner.

[0025] Proximal to the depression, the base body can have at least one further depression, in particular in the form of an annular groove, which can serve as a grip for the surgeon when removing the protective cap from the base body. This is particularly advantageous when the cutting instrument is fluid-filled to improve grip. Proximal to the depression, the base body can have a taper extending towards its proximal end face, which is in particular rotationally symmetrical to the lumen of the base body to facilitate proximal removal of the base body after the tissue incision. The base body can have a diameter between 3 mm and 11 mm, in particular between 6.3 mm and 7.3 mm.

[0026] To protect the patient, the medical cutting instrument may have a protective cap that is detachably connectable to the base body. In particular, the protective cap is provided with a recess in which the blade of the base body is completely enclosed when the protective cap is connected to the base body. The protective cap serves to protect against injury from the blade. Preferably, the protective cap can only be connected to the base body at a predefined angular orientation relative to the blade in order to protect the blade from contamination. For this purpose, the protective cap may have an axially oriented radial projection at a distal end region, which corresponds to a recess in the base body at its distal end region. The protective cap may have an axial length of at least 30 mm.

[0027] In particular, it is provided that a recess in the protective cap, especially in a radially centered area, is aligned with the lumen of the base body when the protective cap is connected to the base body, so that the recess can accommodate the guide wire arranged through the base body. To protect the operator, the cutting instrument is equipped with the protective cap, which allows the cutting instrument to be guided safely over the guide wire. The base body, even with the protective cap attached, can be moved over a guide wire, and at the same time, the blade remains protected from contamination by the protective cap.

[0028] Preferably, the protective cap has an axially oriented slot whose width is greater than the diameter of the lumen of the base body, the slot being designed to communicate with the recess of the protective cap. This allows the protective cap to be removed from the base body without having to remove the cutting instrument itself. For example, the protective cap can be pulled distally away from the base body and removed from the guide wire by a lateral, radial outward movement such that the wire passes through the slot in the protective cap. The slot can taper proximally, particularly in steps. The resulting wider design of the slot in a distal section provides the user with a clear view of the blade. In particular, the slot extends over the entire axial length of the protective cap.

[0029] The protective cap may be designed to widen proximally from its distal end face, which may be flat, particularly in an area associated with the blade. To easily identify the blade's position on the base body, even when the base body is fitted with the protective cap, the cap's surface may have a greater proximal slope in an area associated with the blade and / or parallel to it than in an area opposite the blade. The instrument set may include a working instrument designed for processing or inserting into tissue, and / or an inspection instrument designed for inspecting a work site, particularly a working instrument located there.

[0030] For the purposes of the invention, the tissue to be treated can be the skin surface proximal to the treatment site or tissue located distal to the skin surface, such as muscle or fascial tissue. The treatment site is defined as the location where the actual procedure is performed on the patient's spine.

[0031] Preferably, the medical cutting instrument is fitted with a protective cap when it is inserted into the tissue to be treated. The protective cap is then removed, and the tissue is subsequently treated with the cutting instrument. The procedure may involve the use of an interlaminar and / or transforaminal approach to the surgical site on the spine.

[0032] Further advantages and features of the invention will become apparent from the claims and from the following description, in which an embodiment of the invention is explained in detail with reference to the drawings. The drawings show:

[0033] Fig. 1 shows a schematic side view of the cutting instrument according to the invention.

[0034] Fig. 2 is a view from below of the cutting instrument of Fig. 1, Fig. 3 is a top view of the cutting instrument of Fig. 1.

[0035] Fig. 4 shows an enlarged view of detail A in Fig. 3.

[0036] Fig. 5 shows the cutting instrument of Fig. 1 with a protective cap,

[0037] Figs. 6-10 Illustrations of the cutting instrument according to the invention during the performance of a surgical procedure,

[0038] Fig. 11 shows a schematic side view of the cutting instrument of Fig. 1 without the guide wire.

[0039] Fig. 12 shows a view from below of the cutting instrument of Fig. 11.

[0040] Fig. 13 shows a top view of the cutting instrument of Fig. 11.

[0041] Fig. 14 shows an enlarged view of detail C in Fig. 12.

[0042] Fig. 15 shows a proximal view of the cutting instrument of Fig. 12.

[0043] Fig. 16 shows a distal view of the cutting instrument of Fig. 12.

[0044] Figs. 17-19 show a cutting instrument with a further blade design, Figs. 20-22 show a cutting instrument with a further blade design,

[0045] Fig. 23 shows a protective cap of the cutting instrument in a proximal view.

[0046] Fig. 24 shows the protective cap of Fig. 23 in a top view,

[0047] Fig. 25 shows the protective cap of Fig. 23 in a distal view.

[0048] Fig. 26 shows the protective cap of Fig. 23 in a view from below,

[0049] Fig. 27 shows the cutting instrument with the protective cap according to Fig. 5 in a top view,

[0050] Fig. 28 shows the cutting instrument of Fig. 27 in a view from below,

[0051] Figs. 29-35 show the implementation of a method according to the invention with an interlaminar access and

[0052] Figs. 36-42 show the implementation of a further method according to the invention in a transforaminal approach.

[0053] Fig. 1 shows a schematic side view of a medical cutting instrument 1 according to the invention, with a distal direction to the left and a proximal direction to the right. The cutting instrument 1 has a substantially axially extending base body 2, which, with the exception of its distal end region 3, has a substantially cylindrical shape and tapers conically in the region of the distal end region 3 in a non-rotationally symmetrical radial direction to the radial center 4 of the base body 2 towards the flat distal end face 5 of the base body 2. An upper side 6 of the base body 3 in Fig. 1, which faces away from its blade 7, has a greater slope and thus a larger cone angle than a lower side 8 of the base body 2 in Fig. 1, which faces the blade 7.

[0054] The base body 2 has a lumen 9 arranged within it, which extends over the entire axial length of the base body 2 and is radially centered relative to the cross-section of the base body 2. The lumen 9 is covered by the base body 2 in perspective in Fig. 1 and is not shown there, but is penetrated by a guide wire 10, which, like the cutting instrument 1, is a component of an instrument set 11 according to the invention.

[0055] The base body 2 has an axially oriented slot 12 on its distal end face 5, into which the blade 7, which is also axially oriented, is inserted, extending distally and projecting from the base body 2 by 5 mm to 20 mm, in particular by 15 mm.

[0056] The slot 12 of the base body 2 is arranged eccentrically, i.e., radially offset, from its lumen 9, so that this also applies to the blade 7. Due to its position, orientation, and surface, the blade 7 defines a blade plane 13, which in Fig. 1 is horizontally and parallel to the lumen. The blade 7 is designed to be mirror-symmetrical with respect to a plane of symmetry (not shown in Fig. 1), which corresponds to the perpendicular bisector of the blade plane 13, is thus normal to the blade plane 13, and is located at the level of the lumen 9 of the base body 2. The side view in Fig. 1 shows that the blade 7, and therefore also the blade plane 13, is arranged at a practically minimal distance from the lumen 9 of the base body 2.

[0057] The blade 7 has a centered, distal blade tip 14, which lies in the plane of symmetry of the blade 7 and is axially 15 mm away from the base body 2. The cutting edge 15 of the blade 7 extends proximal to the distal blade tip 5 on both sides to an outer blade corner 16, 17, with both outer blade corners 16, 17 projecting radially 1 mm beyond the base body 2 and being opposite each other. Beyond the outer blade corners 16, 17, the cutting edge 15 of the blade 7 runs proximally parallel to the lumen 9, the transition of the blade 7, in particular the transition from its cutting edge 15 to the base body 2, being smooth. In this respect, the blade 7 is arrow-shaped, as also shown in Figures 2 and 3.

[0058] The base body 2 has an axially oriented recess 19 on its lower side 8 in Fig. 1 in its distal end region 3, which widens proximally. This recess serves to receive a radial projection 18 of a protective cap 21 associated with the base body 2 (not shown in Fig. 1), which is designed complementarily to this projection. The projection 18 of the protective cap 21 extends through the recess 19 to secure the protective cap 21 to the base body 2, allowing the protective cap 21 to be connected to the base body 2 at a defined angular angle.

[0059] Proximal to the distal end region 3 of the base body 2, the base body 2 has an annular groove 20 with an axial length of 3 mm for a positive-locking connection with the protective cap 21 described below. Proximal to the recess 20, the base body 2 has further axially arranged annular grooves 22, 23, the axially central annular groove 22 serving as a retaining grip, particularly when the protective cap 21 is placed on the base body 2.

[0060] The proximal annular groove 23 serves, for example, to allow the operator to operate the cutting instrument 1, wherein the cross-section of the base body 2 tapers proximal to the proximal annular groove 23 towards its proximal, flat end face 24 in order to make it easier to attach further instruments, in particular working sleeves, subsequently inserted over the base body 2.

[0061] Fig. 2 shows the cutting instrument 1 of Fig. 1 in a bottom view, in which the blade 7 covers the guide wire 10 received in the lumen 9 of the base body 2, and from which the arrow-shaped design of the blade 7 and the course of the cutting edge 15 are evident. Proximal to the blade 7, the axially oriented recess 19 of the base body 2, as already described, is visible. The blade 7 is inserted into the axial slot 12 of the base body 2 and bonded to it there, as already described. Fig. 2 also shows that the blade 7, particularly at its outer blade corners 16, 17, projects slightly radially beyond the base body 2 to facilitate its insertion into the tissue 25 after the tissue incision has been made, as described further below.

[0062] Fig. 3 shows the cutting instrument 1 of Fig. 1 in a top view, from which the arrangement of the blade 7 relative to the lumen 9, through which the guide wire 10 runs, is evident, in particular its mirror-symmetrical design. The upper side 6 of the distal end region 3 of the base body 2 in Fig. 1 is facing the viewer in Fig. 3 and has a grip recess 26 to improve the operation of the cutting instrument 1 by the operator.

[0063] Fig. 4 shows an enlarged view of detail A of Fig. 3, namely the blade 7 which in this view is partially covered by the guide wire 10, showing in particular the two outer blade corners 16, 17, the cutting edge 15 and the edgeless transitions from the blade 7 to the base body 2.

[0064] Fig. 5 shows the cutting instrument 1 of Fig. 1, which is provided with the protective cap 21. The protective cap 21 was moved from distal to proximal onto the cutting instrument 1 until a radially inwardly projecting locking projection of the protective cap 21 (not shown in Fig. 5) engages in the distal annular groove 20 associated with the protective cap 21. This secures the protective cap 21 to the base body 2 in a defined axial position, allowing it to be releasably connected to the base body 2 in such a way that the protective cap 21 completely covers the blade 7. Furthermore, the radially inwardly oriented projection 18 of the protective cap 21 engages in the correspondingly designed recess 19 on the lower side 8 of the base body 2. When removing the protective cap 21, the axially central annular groove 22 of the base body can be used for retention. The protective cap 21 has a [feature] shown in Fig.Figure 5 shows a perspectively covered, lumen-shaped recess 32, which extends over the entire axial length of the protective cap 21 and is designed to receive the blade 7 of the base body 2. In the area of ​​the blade 7, a pocket-shaped recess 36 is formed. The guide wire 10, not shown in Figure 5, extends not only through the base body 2 but also through the protective cap 21 when the latter is connected to the base body 2, since the recess 32 of the protective cap 21 is aligned with the lumen 9 of the base body 2.

[0065] The protective cap 21 has a substantially flat distal end face 27, with the protective cap 21 widening proximally with a convex curvature in a lower region 28 associated with the blade 7, while it does not widen proximally in an upper region 29 facing away from the blade 7 (shown in Fig. 5). On this upper side 29, the blade 7 has an axially oriented slot 33 (not shown in Fig. 5), the width of which is slightly larger than the diameter of the guide wire 10 and thus substantially corresponds to the diameter of the lumen 9 of the base body 2. This allows the protective cap 21 to be pulled distally from the base body 2 and removed laterally, i.e., perpendicular to the axial direction, without the need to remove the cutting instrument 1 itself proximally. The cutting instrument 1 can remain in its current position and, after removal of the protective cap 21, immediately perform the intended tissue incision.For this purpose, the slot 33 is designed to communicate with the recess 32 of the protective cap 21. Figures 6 to 10 show the use of the cutting element 1 according to the invention in the context of a surgical procedure on a patient's spine (not shown). First, using the known Seldinger technique, the guide wire 10 is inserted through the patient's tissue 25 (schematically shown in Figure 6) to the site of the procedure, using a hollow needle (not shown in Figure 6). After the guide wire 10 is positioned as desired, the hollow needle is removed, with the guide wire 10 penetrating the patient's skin surface 30 at the treatment site 31, in the vicinity of which the tissue incision (a skin incision in the illustrated embodiment) is to be made. Subsequently, the cutting instrument 1 according to the invention is used as shown in Figure 1.5, thus with the protective cap 21 attached, is moved from proximal to distal over the guide wire 10, as shown in the transition from Fig. 6 to Fig. 7. The guide wire 10 passes through the lumen 9 of the base body 2 and the recess 32 of the protective cap 21, and therefore emerges in particular from the distal end face 27 of the same.

[0066] Due to the design of the slot 33 in the protective cap 21, the surgeon can verify the correct alignment of the blade 7 without having to remove the protective cap 21 from the base body 2. The cutting instrument 1 is moved further distally to the vicinity of the treatment site 31, where, as already mentioned, the guide wire 10 penetrates the patient's skin surface 30.

[0067] In this position, shown in Fig. 8, the operator pulls the protective cap 21 distally away from the base body 2, thus releasing the connection between the protective cap 21 and the base body 2, so that the blade 7 of the cutting instrument 1 is exposed. The operator uses the axially central annular groove 22 of the base body 2 as a grip. The guide wire 10 still penetrates, in particular, the protective cap 21. Transitioning to Fig. 9, the operator moves the protective cap 21 laterally, downwards as shown in the side view of Fig. 9, such that the guide wire 10 penetrates the slot 33 located at the top of the protective cap 21, allowing the protective cap 21 to finally be removed. Meanwhile, the base body 2 and the blade 7 of the cutting instrument 1 remain in their previous positions.

[0068] Starting from Fig. 9, the cutting instrument 1 is moved distally in the transition to Fig. 10. This causes the distal blade tip 14 to penetrate the patient's skin surface 30, creating a puncture that is positioned in the projection of the guide wire 10 onto the blade plane 13, but slightly radially spaced from the guide wire 10, and thus also at a short distance from the treatment site 31. Due to the cutting edge 15, which extends proximally and outwards on both sides of the distal blade tip 14, the puncture is widened distally on both sides of the distal blade tip 14 as the cutting instrument 1 continues to move, until the resulting skin incision reaches its greatest extent when the two outer blade corners 16, 17 of the blade 7 pass the patient's skin surface 30.

[0069] With continued distal movement of the cutting instrument 1, the blade 7 penetrates further into the patient's skin surface 30, so that the skin surface 30 comes into contact with the distal end face 5 of the base body 2. Due to the seamless transition from the blade 7 to the base body 2, this occurs with minimal risk of trauma. As the base body 2 is moved further distally, the skin surface 30 is widened as a result of the proximally widening, conical distal end region 3 of the base body 2, so that the base body 2, and thus the cutting instrument 1 as a whole, assumes the function not only of a scalpel but also of a dilator.With further distal movement of the base body 2, the skin surface 30, together with the underlying tissue 25, for example, also fascial tissue distal to the patient's skin surface 30, is eventually expanded to the diameter of the base body 2 when the distal end region 3 of the base body has passed the skin surface 30. This position is shown in Fig. 10. The further distal movement of the cutting instrument 1 is facilitated by the blade 7 continuing to project distally.

[0070] Once the cutting instrument 1 is positioned at its desired axial position, further instruments can be positioned at the site of intervention. For example, additional dilators for tissue expansion can be advanced over the cutting instrument 1, from proximal to distal, along the guide wire 10 and over the cutting instrument 1. Alternatively or additionally, a guide rod and / or a working sleeve and / or an endoscope can be advanced distally to the site of intervention. The guide wire, the cutting instrument 1, and the dilators can then be removed proximally. The working sleeve can then be used to advance the surgical instruments to the site of intervention.

[0071] Fig. 11 shows the cutting instrument 1 of Fig. 1 without the guide wire 10 in a schematic side view, so that reference is made to the preceding statements to avoid repetition. In particular, Fig. 11 shows the blade 7 inserted into the slot 12 of the base body 2 and bonded to the base body 2. Fig. 12 corresponds to a bottom view of the cutting instrument 1 of Fig. 11 and thus essentially to Fig. 2. From Fig. 12, the mirror-symmetrical design of the blade 7, including its two outer blade corners 16, 17, is particularly evident. Fig. 13 shows the cutting instrument 1 of Fig. 11 in a top view and therefore corresponds to Fig. 3 with the exception of the guide wire 10 shown there. In Fig. 14, detail C of Fig. 12 is shown enlarged, so that Fig.14 next to the part of the blade 7 that projects distally beyond the base body 2, the lower side 8 of the base body 2 is partially visible, in particular its axially oriented recess 19. The recess 19 is aligned with the lumen 9 of the base body 2.

[0072] Fig. 15 shows the cutting instrument 1 in a proximal view, from which its proximal end face 24 and the radially centered arrangement of the lumen 9 are visible. In the illustrated embodiment, the cross-section of the lumen 9 is not circular, but has a linear region and a curved region, which together resemble the letter "D". Fig. 16 shows the cutting instrument 1 in a distal view, from which the radially centered arrangement of the lumen 9 and the distal end face 5 of the base body are also visible. As already mentioned, the blade 7 is arranged at a minimal distance from the lumen 9, thus radially eccentric, and projects slightly radially beyond the base body 2. Fig. 16 also shows that the axially oriented recess 19 on the lower side 8 of the base body has an approximately rectangular cross-section.

[0073] Figures 17 to 19 show a cutting instrument 1 with a further embodiment of the blade 7, which, particularly as shown in Figure 17, widens on both sides with a slight concave curvature from the centrally arranged distal blade tip 14 to two outer blade corners 16, 17. The outer blade corners 16, 17 are arranged approximately at the axial height of the distal end face 5 of the base body 2. Therefore, the part of the blade 7 projecting distally beyond the base body 2 has a shorter axial length than the blade according to Figure 1. The upper side 6 of the base body has the aforementioned grip recess 26. Figure 18 shows the cutting instrument 1 of Figure 17 in a schematic longitudinal section through the perpendicular bisector of Figure 17, which also corresponds to the axis of symmetry of the blade 7. As already mentioned, the blade 7 is inserted into the slot 12 of the base body 2 and glued to it there.The lumen 9 runs through the base body immediately adjacent to the blade 7. On the lower side 8 of the base body 2, the axially oriented recess 19 for connection with the protective cap 21 is arranged. Fig. 19 shows the cutting instrument 1 of Fig. 17 in a distal view, i.e., on its distal end face 5. Therefore, Fig. 19 essentially corresponds to Fig. 16 except for the lumen 9, which has a circular base in Fig. 19.

[0074] Figures 20 to 22 show a cutting instrument 1 with a further embodiment of the blade 7, which, particularly according to Figure 20, widens essentially linearly from the distal blade tip 14 proximally to two outer blade tips 34, 35 and then tapers linearly again until the transition to the base body 2. As a result, the two outer blade tips 34, 35 have a greater radial distance from the base body 2 than the two outer blade corners 16, 17 in the embodiment of the blade according to Figure 14. In this embodiment as well, the upper side 6 of the base body 2 is provided with a grip recess. Figure 21 shows the cutting instrument 1 of Figure 21 in a longitudinal section and thus corresponds to Figure 18. The same applies to the view of the cutting instrument 1 of Figure 20 from distal to Figure 21. 22, which essentially corresponds to Fig. 22.

[0075] Figures 23 to 26 show an embodiment of the protective cap 21 for use with the base body 2. In the proximal view of the protective cap 21 according to Figure 23, the arrangement of the previously mentioned slot 33 in the upper region 29, located on the left in Figure 23, is visible. The slot 33 extends over the entire axial length of the protective cap 21 and corresponds to the radially centered recess 32, which is also previously mentioned and is designed to communicate with a pocket 36 for receiving the blade 7. The pocket 36 is shaped according to the form of the blade 7 and has a rectangular shape as shown in Figure 23. Furthermore, as already mentioned, the recess 32 of the protective cap is designed to receive the guide wire 10, which passes through the lumen 9 of the base body 2.In the lower region 28, the protective cap 21 has a radially inwardly projecting projection 18, which corresponds to the recess 19 on the lower side 8 of the base body. Opposite the projection 18, the protective cap 21 has two radially inwardly projecting locking projections 37, 38, each extending circumferentially over a quarter circle, which are designed to engage in the distal annular groove 20 of the base body 2.

[0076] Fig. 24 shows the protective cap 21 of Fig. 23 in a top view of its upper region 29, which shows the slot 33, the recess 32 and the projection 18. Fig. 25 shows the protective cap 21 in a distal view, from which the slot 33 and the recess 32 are also visible. Fig. 26 shows the protective cap 21 in a bottom view and therefore in particular the widening lower region 28.

[0077] Fig. 27 shows the base body 2 connected to the protective cap 21 according to Fig. 5 in a top view of its upper region 29. In addition to the features already mentioned, it can be seen that the protective cap 21 covers the distal annular groove 20 of the base body 2, with the previously mentioned locking projections 37, 38 engaging in this groove. Fig. 28 shows the cutting instrument 1 of Fig. 27 in a bottom view of its lower region 28.

[0078] Figures 29 to 35 show the use of the cutting instrument 1 according to the invention as part of an instrument set 11 during a surgical procedure on a spine 39 using an interlaminar approach via the interlaminar window between two adjacent vertebral bodies 40, 41 from the posterior and lateral sides. The interlaminar approach is particularly suitable as an access route in the lower region of the lumbar vertebrae 40, 41, since the interlaminar window is comparatively large there.

[0079] First, a hollow needle 42 is inserted to the site of intervention, as shown in Fig. 29, to create access. The hollow needle 42 has a beveled distal end 43 and a proximal handle 44. A stylet, shown in perspective as in Fig. 29, is inserted into the hollow needle 42, its distal end face being flush with the beveled distal end 43 of the hollow needle 42. The hollow needle 42, together with the stylet inserted into the hollow needle 42, is advanced through an incision in the patient's skin near the vertebra to be treated, under X-ray guidance, to the site of intervention. The stylet is then withdrawn proximally. In the transition to Fig. 30 The guide wire 10 is inserted proximally through the hollow needle 42 to the insertion site, the diameter of the guide wire 10 being adapted to the lumen of the cylindrical cavity of the hollow needle 42. Subsequently, as shown in Fig.31 The hollow needle 42 is removed, leaving only the guide wire 10. In the transition to Fig. 32, the cutting instrument 1 with its associated protective cap 21, as part of the instrument set 11, is moved from proximal to distal over the guide wire 10 until the guide wire 10 completely penetrates the lumen 9 of the cutting instrument 1, as shown in Fig. 33. The cutting instrument 1 is then moved further distally along the guide wire 10 to the tissue 25 to be treated, as also shown in the previously described Figs. 6 and 7. As described in connection with Fig. 8, the protective cap 21 is pulled distally away from the base body 2, as shown in Fig. 34, so that the blade 7 of the cutting instrument 1 is exposed. The protective cap 21 is now removed according to Fig. 35, similar to Fig. 9, by a lateral movement in which the guide wire 10 passes through the slot 33 of the protective cap 21.The cutting instrument 1 is advanced further distally, so that the tissue 35 (not shown in Fig. 35) is processed and spreads open due to the continued distal insertion of the cutting instrument 1. A working sleeve (not shown) is then inserted over the cutting instrument 1 to the actual treatment site, after which the cutting instrument 1 is withdrawn proximally. A working instrument and / or an endoscope can then be inserted over the working sleeve to the treatment site and processed there. Once the treatment at the treatment site is complete, the instruments are withdrawn proximally from the treatment site.

[0080] Figures 36 to 42 show the use of the cutting instrument 1 in a surgical procedure on the spine similar to that described in connection with Figures 29 to 35, but here using a transforaminal approach to the intervention site on the spine 39 between two adjacent vertebral bodies 40, 41 from a lateral direction. The steps of the procedure essentially correspond to the steps of the interlaminar approach already described according to Figures 29 to 35: Insertion of the hollow needle 42 with the stylet inserted – via the transforaminal approach – to the intervention site (Figure 36), removal of the stylet from the hollow needle 42, insertion of the guide wire 10 through the hollow needle 42 to the intervention site (Figure 37), removal of the hollow needle 42 proximally (Figure 38), insertion of the cutting instrument 1 with the protective cap 21 attached from proximally over the guide wire distally (Figures 39 and 40), removal of the protective cap 21 distally (Figure 39).41) , Removal of the protective cap 21, lateral and distal movement of the cutting instrument while working and simultaneous spreading of the tissue 25 (not shown) (Fig. 42). The subsequent insertion of the working sleeve, the working instrument and / or the endoscope to work the procedure site and the subsequent removal of the instruments from the procedure site are not shown.

Claims

Patent claims 1. Medical cutting instrument (1) for tissue (25) for use in surgical, in particular endoscopic, procedures on the spine, comprising a substantially axially extending base body (2) and a blade (7) which is connected to the base body (2) in a distal end region (3) and which has a distally oriented cutting edge (15), wherein the blade (7) projects distally beyond the base body (2), characterized in that the cutting instrument (1) has an axial lumen (9) extending over the entire length of the cutting instrument (1).

2. Medical cutting instrument (1) according to claim 1, characterized in that the lumen (9) is arranged radially centered relative to the cross-section of the base body (2).

3. Medical cutting instrument (1) according to one of claims 1 or 2, characterized in that the blade (7) has a distal blade tip (14).

4. Medical cutting instrument (1) according to one of claims 1 to 3, characterized in that the blade (7), in particular the distal blade tip (14), is arranged radially eccentrically to the lumen (7) of the base body (2).

5. Medical cutting instrument (1) according to one of claims 1 to 4, characterized in that the cutting edge (15) of the blade (7) has a blade plane (13) defined, wherein the distal blade tip (14) is encompassed by a plane arranged normal to the blade plane (13) and at the level of the lumen (9) of the base body (2).

6. Medical cutting instrument (1) according to one of claims 3 to 5, characterized in that the cutting edge (15) of the blade (7) extends from the distal blade tip (14) proximally to a first outer blade corner (16), in particular a first outer blade tip (34).

7. Medical cutting instrument (1) according to one of claims 3 to 6, characterized in that the cutting edge (15) of the blade (7) extends from the distal blade tip (14) proximally to both sides of the blade (7).

8. Medical cutting instrument (1) according to one of claims 6 or 7, characterized in that the cutting edge (15) extends from the distal blade tip (14) extends proximally to a second outer blade corner (17), in particular a second outer blade tip (35), which is arranged in particular opposite the first outer blade corner (16), in particular the first outer blade tip (34).

9. Medical cutting instrument (1) according to one of claims 6 to 8, characterized in that the at least one outer blade corner (16, 17) , in particular at least one outer blade tip (34, 35) projects radially beyond the base body (2) , in particular its largest diameter .

10. Medical cutting instrument (1) according to one of claims 6 to 9, characterized in that the blade (7) tapers from the at least one outer blade tip (34, 35) proximally, in particular to the base body (2).

11. Medical cutting instrument (1) according to one of claims 1 to 10, characterized in that at least one transition of the blade (7), in particular of its cutting edge (15), to the base body (2) is designed without edges.

12. Medical cutting instrument (1) according to one of claims 1 to 11, characterized in that the blade (7) is designed at least sectionally in a mirror-symmetrical manner with respect to a plane which is arranged centrally and normal to the blade plane (13) and / or at the level of the lumen (9) of the base body (2).

13. Medical cutting instrument (1) according to one of claims 1 to 12, characterized in that the blade (7) is connected to the base body (2) by form and / or force and / or material interlocking.

14. Medical cutting instrument (1) according to one of claims 1 to 13, characterized in that the base body (2) has, in particular on its distal end face (5), a slot (12) in which the blade (7) is inserted, in particular bonded to the base body (2).

15. Medical cutting instrument (1) according to one of claims 1 to 14, characterized in that the base body (2) widens from the distal end face (5) proximally, in particular conically.

16. Medical cutting instrument (1) according to claim 15, characterized in that the base body (2) has a smaller cone angle in a region (8) facing the blade (7) than in a region (6) facing away from the blade (7).

17. Medical cutting instrument (1) according to one of claims 1 to 16, characterized by a protective cap (21) which is detachably connectable to the base body (2), wherein it is particularly provided that the protective cap (21) has an interior space in which the blade (7) of the base body (2) is completely received when the protective cap (21) is connected to the base body (2).

18. Medical cutting instrument (1) according to claim 17, characterized by a locking recess (20) of the base body (2) associated with the protective cap (21), into which a projection of the protective cap (21) can be engaged.

19. Medical cutting instrument (1) according to one of claims 17 or 18, characterized in that a recess (32) of the protective cap (21) is aligned with the lumen (9) of the base body (2) when the protective cap (21) is connected to the base body (2).

20. Medical cutting instrument (1) according to one of claims 17 to 19, characterized in that the protective cap (21) has an axially oriented slot whose width is greater than the diameter of the lumen (9) of the base body (2), wherein the slot is designed to communicate with the recess (32) of the protective cap.

21. Medical cutting instrument (1) according to one of claims 18 to 20, characterized in that the protective cap (21) is designed to widen proximally from its distal end face (27), in particular in an area associated with the blade (7). (28) .

22. Instrument set (11) comprising a medical cutting instrument (1) according to one of claims 1 to 21 and comprising at least one of the following instruments: needle, in particular hollow needle (42), preferably with stylet inserted therein, guide wire (10), awl, drill, milling cutter, dilator, working sleeve, working instrument, endoscope.

23. Method of performing a surgical procedure on the spine (39) at a surgical site with a medical cutting instrument (1) according to any one of claims 1 to 21, in particular with an instrument set (11) according to claim 22, comprising the following steps: Creating access to the intervention site via a hollow needle (42), in particular with a stylet inserted therein, inserting a guide wire (10) to the intervention site, Inserting the medical cutting instrument (1) distally over the guide wire (10) to a tissue (25) of the patient to be treated, moving the medical cutting instrument (1) distally along the guide wire (10) such that the blade (7) of the medical cutting instrument (1) treats the tissue (25), whereby the medical cutting instrument (1) is guided further distally and, in particular, the treated tissue (25) spreads due to the geometry of the medical cutting instrument (1), inserting a working sleeve over the cutting instrument (1) to the treatment site, removing the cutting instrument (1) proximally, inserting a working instrument and / or an endoscope to the treatment site and treating the treatment site.

24. Method according to claim 23, characterized in that the medical cutting instrument (1) is provided with the protective cap (21) when it is inserted into the tissue (25) to be processed, the protective cap (21) is removed and then the processing of the tissue (25) is carried out with the cutting instrument (1).

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