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

Abstract

The invention relates to a medical cutting instrument for tissue for use in surgical, in particular endoscopic, procedures on the spine. The cutting instrument has a substantially axially extending base body and a blade that is connected to the base body in a distal region and has a distally oriented cutting edge. The blade projects distally beyond the base body. The cutting instrument has an axial lumen extending over its entire length. The invention also relates to an instrument set comprising the cutting instrument and a method for performing a surgical procedure using the cutting instrument.

Description

[0001] 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, wherein the blade projects distally beyond the base body. The invention further relates to a medical instrument set and a method for an endoscopic procedure on the spine.

[0002] 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 during the procedure can reliably reach the site. Before other 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 the area surrounding the guide wire using a scalpel guided freely by the surgeon. The other instruments are then advanced through this incision to their insertion points. A disadvantage of this method is that the manual, free execution of the tissue incision can lead to variations in its position relative to the guide wire.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 makes the insertion of further instruments more difficult and can lead to tissue trauma.

[0003] 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.

[0004] 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.

[0005] 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.

[0006] 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: - 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 the tissue of the patient to be treated, - Moving the medical cutting instrument distally along the guide wire such that the blade of the medical cutting instrument processes the tissue, whereby the medical cutting instrument is guided further distally and, in particular, the processed tissue spreads due to the geometry of the medical cutting instrument, - Inserting a working sleeve over the cutting instrument to the intervention site, - Removal of the cutting instrument proximally, - Inserting a surgical instrument and / or an endoscope to the site of the procedure and working on the site of the procedure.

[0007] A fundamental principle 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 placed on the spine during the procedure, 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 as a whole.

[0008] In particular, when, during an endoscopic procedure using the known Seldinger technique, a needle is first inserted 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, enabling the tissue incision to be made 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 available for the procedure.

[0009] 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 with a circular cross-section, that extends 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.

[0010] 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 surgical site. An axial direction points from proximal to distal or vice versa. In the context of a three-dimensional cylindrical coordinate system, a radial direction and a circumferential direction are each perpendicular to the axial direction and to each other.

[0011] Preferably, the lumen is arranged radially centered relative to the cross-section of the base body. The base body may have a circular cross-section, at least in some areas. In a further development of the invention, the lumen itself may 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, facilitating 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 the procedure. 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.

[0014] Preferably, the cutting edge of the blade defines a blade plane, wherein the distal blade tip is encompassed by a plane 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.

[0015] 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 may have a concave curvature, particularly in this region.

[0016] The cutting edge of the blade can extend from the distal tip proximally 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 repositioning it to extend the existing incision in the opposite direction. By designing the cutting edge as described above, this second cut is unnecessary, as the instrument cuts in both directions simultaneously. The cutting edge can therefore be arrow-shaped.

[0017] 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.

[0018] Preferably, 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 particularly by 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.

[0019] The blade can taper proximally from the at least one outer blade tip, particularly towards the base body, and especially from both outer blade tips towards the base body. In this way, the at least one outer blade corner is formed as a blade tip. In a further development of the invention, it can be provided that the blade widens proximally from the distal blade tip to the base body, so that the blade has a triangular base shape.

[0020] 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.

[0021] Preferably, the blade is designed at least partially with mirror symmetry 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 with complete mirror symmetry. 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.

[0022] 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.

[0023] 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 have an atraumatic rounding, particularly in the area of ​​the transition between the blade and the base body, to reduce the risk of trauma.

[0024] Preferably, the main body 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 speeding up the procedure overall. In this way, the medical cutting instrument can be considered a combination of a scalpel and a dilator.

[0025] 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 shallower 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 initial incision. The instrument body can also feature a grip recess on the side facing away from the blade to improve the surgeon's handling of the cutting instrument.

[0026] Proximal to its distal end, the base body can have at least a partially cylindrical shape. In particular, the base body can have a concavely curved recess, for example, in the form of an annular groove, around its entire circumference. This groove 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 on 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.

[0027] 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-lubricated 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.

[0028] To protect the patient, the medical cutting instrument can have a protective cap that is detachably connectable to the base body. In particular, the protective cap has 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 can 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 can have an axial length of at least 30 mm.

[0029] 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.

[0030] 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, by a lateral, radial outward movement, removed from the guide wire 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.

[0031] 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 angle of inclination proximally in an area associated with the blade and / or parallel to it than in an area facing away from the blade.

[0032] The instrument set may include a working instrument designed for processing or inserting into tissue, and / or an inspection instrument designed for inspecting a site of use, in particular a working instrument located there.

[0033] For the purposes of the invention, the tissue to be treated can be the skin surface proximal to the application site or tissue located distal to the skin surface, such as muscle or fascial tissue. The application site is defined as the location where the actual procedure is performed on the patient's spine.

[0034] 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 treatment site on the spine.

[0035] 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. These show: Fig. 1 a schematic side view of the cutting instrument according to the invention, Fig. 2 A view from below of the cutting instrument of the Fig. 1, Fig. 3 a view of the cutting instrument of the Fig. 1, Fig. 4 an enlarged view of detail A in Fig. 3, Fig. 5 the cutting instrument of the Fig. 1 with a protective cap, Fig. 6-10 Illustrations of the cutting instrument according to the invention during the performance of a surgical procedure, Fig. 11 a schematic side view of the cutting instrument of the Fig. 1 without guide wire, Fig. 12 A view from below of the cutting instrument of the Fig. 11, Fig. 13 a supervision of the cutting instrument of the Fig. 11, Fig. 14 an enlarged view of detail C in Fig. 12, Fig. 15 a view of the cutting instrument of the Fig. 12 from proximal, Fig. 16 a view of the cutting instrument of the Fig. 12 from distal, Fig. 17-19 a cutting instrument with a further modification of the blade, Fig. 20-22 a cutting instrument with a further modification of the blade, Fig. 23 a protective cap of the cutting instrument in a proximal view, Fig. 24 the protective cap of the Fig. 23 in a supervisory role, Fig. 25 the protective cap of the Fig. 23 in a distal view, Fig. 26 the protective cap of the Fig. 23 in view from below, Fig. 27 the cutting instrument with the protective cap according to Fig. 5 in a supervision, Fig. 28 the cutting instrument of the Fig. 27 in a view from below, Fig. 29-35 the implementation of a method according to the invention with an interlaminar access and Fig. 36-42 the implementation of a further method according to the invention in a transforaminal approach.

[0036] Fig. Figure 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 basic 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. A Fig. 1 The upper side 6 of the base body 3, which faces away from its blade 7, has a greater slope and thus a larger cone angle than a side 6 of the base body 3. Fig. 1 lower side 8 of the base body 2, which faces the blade 7.

[0037] 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 in Fig. 1 is covered in perspective by the base body 2 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.

[0038] The base body 2 has an axially oriented slot 12 on its distal end face 5, into which the axially oriented blade 7 is inserted. The blade 7 therefore extends distally and projects 5 mm to 20 mm, particularly 15 mm, distally from the base body 2. The slot 12 of the base body 2 is arranged eccentrically, i.e., radially offset, from its lumen 9, and this also applies to the blade 7. Due to its position, orientation, and surface area, the blade 7 defines a Fig. 1. Blade plane 13, horizontally and parallel to the lumen. The blade 7 is mirror-symmetrical to a plane 13. Fig. 1. The symmetry plane (not shown) is designed to correspond to the perpendicular bisector of the blade plane 13, thus being normal to the blade plane 13 and being located at the height of the lumen 9 of the base body 2. In the side view of the Fig. Figure 1 shows that the blade 7, and therefore also the blade plane 13, is arranged at a practically minimal distance to the lumen 9 of the base body 2.

[0039] 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, which is also reflected in the Fig. 2 and Fig. 3 is shown.

[0040] The basic body 2 has in its distal end region 3, which widens proximally, on the lower side 8 in Fig. 1 an axially oriented recess 19, which is designed to receive a radial projection 18 of a base body 2 associated with it, in Fig. 1 protective cap 21 not shown, so that the projection 18 of the protective cap 21 extends through the recess 19 to attach the protective cap 21 to the base body 2, so that the protective cap 21 can be connected to the base body 2 in a defined angular orientation.

[0041] 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 grip, particularly when the protective cap 21 is placed on the base body 2.

[0042] 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 front face 24 in order to make it easier to attach further instruments, in particular working sleeves, subsequently inserted over the base body 2.

[0043] Fig. Figure 2 shows the cutting instrument 1 of the Fig. Figure 1 shows 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 visible. 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 It is also evident that the blade 7 protrudes slightly radially beyond the base body 2, particularly through the outer blade corners 16, 17, in order to facilitate its insertion into the tissue 25 after the tissue incision has been made, as described below.

[0044] Fig. Figure 3 shows the cutting instrument 1 of the Fig. 1 in a top view showing the arrangement of the blade 7 relative to the lumen 9 through which the guide wire 10 runs, in particular its mirror-symmetrical design. The in Fig. 1 upper side 6 of the distal end region 3 of the base body 2 is in Fig. 3 faces the viewer and has a grip recess 26 to improve the operation of the cutting instrument 1 by the operator.

[0045] Fig. Figure 4 shows an enlarged view of detail A of the Fig. 3, namely the blade 7 which in this view is partially covered by the guide wire 10, in particular showing the two outer blade corners 16, 17, the cutting edge 15 and the edgeless transitions from the blade 7 to the base body 2.

[0046] Fig. Figure 5 shows the cutting instrument 1 of the Fig. 1, which is equipped with the protective cap 21, which was moved from distal to proximal onto the cutting instrument 1 until a Fig. The radially inwardly projecting locking projection of the protective cap 21 (not shown) engages in the distal annular groove 20 associated with the protective cap 21, so that the protective cap 21 is positively locked but detachably connected to the base body 2 in a defined axial position such 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 as a retaining element. The protective cap 21 has a Fig. 5 perspectively covered, lumen-shaped recesses 32 extend over the entire axial length of the protective cap 21 and are 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 in Fig. The guide wire 10 (not shown) not only passes through the base body 2 but also through the protective cap 21 when it 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.

[0047] The protective cap 21 has a substantially flat distal end face 27, wherein the protective cap 21 widens proximally with a convex curvature in a lower region 28 associated with the blade 7, while it curves proximally away from the blade 7 in a Fig. 5 upper area 29 not widened. On this upper side 29, the blade 7 has an axially aligned, in Fig. The 5 not shown slot 33, the width of which is slightly larger than the diameter of the guide wire 10 and thus essentially corresponds to the diameter of the lumen 9 of the base body 2, 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. Instead, 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.

[0048] The Fig. 6 to Fig. Figure 10 shows the use of the cutting element 1 according to the invention during a surgical procedure on a patient's spine (not shown). First, using the known Seldinger technique, a [missing text] is used. Fig. 6 hollow needles (not shown) of the guide wire 10 through the in Fig. Six schematically shown tissues 25 of the patient are arranged up to the site of the procedure where the actual procedure is to take place. After the guide wire 10 is positioned as desired, the hollow needle is removed, the guide wire 10 penetrating the skin surface 30 of the patient at the treatment site 31, in the vicinity of which the tissue incision, which in the illustrated embodiment is a skin incision, is to be made. Subsequently, the cutting instrument 1 according to the invention is Fig. 5, thus with the protective cap 21 attached, moved from proximal to distal over the guide wire 10, which in the transition of Fig. 6 to Fig. Figure 7 shows the guide wire 10 passing 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 front face 27 of the same.

[0049] 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.

[0050] In this position, which is in Fig. As shown in Figure 8, the surgeon 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 surgeon uses the axially central annular groove 22 of the base body 2 as a handle. The guide wire 10 still penetrates, in particular, the protective cap 21. In the transition to Fig. 9. The surgeon moves the protective cap 21 laterally, according to the side view of the Fig. 9 downwards, 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 be removed. Meanwhile, the base body 2 and the blade 7 of the cutting instrument 1 remain in their previous positions.

[0051] Starting from Fig. 9 the cutting instrument 1 in the transition to Fig. The cutting instrument 1 is moved distally. As a result, the distal blade tip 14 first penetrates 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 extending 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.

[0052] 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 in . Fig. Figure 10 shows that the further distal movement of the cutting instrument 1 is facilitated by the blade 7, which continues to project distally.

[0053] Once the cutting instrument 1 is positioned at its desired axial position, further instruments can be positioned at the site of the procedure. These include, for example, additional dilators for tissue expansion, which 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 the procedure. 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 the procedure.

[0054] Fig. Figure 11 shows the cutting instrument 1 of the 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, in Fig. 11 the blade 7 which is inserted into the base body 2 in its slot 12 and glued to the base body 2 is visible. Fig. Figure 12 corresponds to a view from below of the cutting instrument 1 of the Fig. 11 and thus essentially the Fig. 2. From Fig. 12 shows in particular the mirror-symmetrical design of the blade 7 including its two outer blade corners 16, 17. Fig. Figure 13 shows the cutting instrument 1 of the Fig. 11 in a supervisory role and therefore corresponds Fig. 3 with the exception of the guide wire shown there 10. In Fig. 14 is detail C of the Fig. 12 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.

[0055] Fig. Figure 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.

[0056] In the illustrated embodiment, the cross-section of the lumen 9 is not circular, but has a linear area and a curved area, which together are shaped similarly to the letter “D”.

[0057] Fig. Figure 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.

[0058] The Fig. Figures 17 to 19 show a cutting instrument 1 with a further embodiment of the blade 7, which is particularly characterized by Fig. Starting from the centrally located distal blade tip 14, the blade widens on both sides with a slight concave curvature to two outer blade corners 16, 17. The outer blade corners 16, 17 are located approximately at the axial height of the distal end face 5 of the base body 2. Therefore, the portion of the blade 7 extending distally beyond the base body 2 has a shorter axial length than the blade according to [reference missing]. Fig. 1. The upper side 6 of the base body has the previously mentioned recessed grip 26. Fig. Figure 18 shows the cutting instrument 1 of the Fig. 17 in a schematic longitudinal section through the perpendicular bisector of the Fig. 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 bonded 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 aligned recess 19 for connection with the protective cap 21 is arranged. Fig. Figure 19 shows the cutting instrument 1 of the Fig. 17 in a distal view, thus on its distal frontal face 5. Therefore corresponds Fig. 19 essentially the Fig. 16 with the exception of lumen 9, which is in Fig. 19 has a circular base.

[0059] The Fig. Figures 20 to 22 show a cutting instrument 1 with a further embodiment of the blade 7, which is particularly characterized by Fig. 20 widens proximally from the distal blade tip 14 essentially linearly 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 blade configuration according to Fig. 14. In this embodiment as well, the upper side 6 of the base body 2 is provided with a grip recess. Fig. Figure 21 shows the cutting instrument 1 of the Fig. 21 in a longitudinal section and therefore corresponds to the Fig. 18. The same applies to the view of cutting instrument 1 of the Fig. 20 from distal to Fig. 22, which are essentially the Fig. 22 corresponds to.

[0060] The Fig. 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 Fig. 23 is the arrangement of the already mentioned slot 33 in which in Fig. The upper area 29, arranged on the left, is recognizable. The slot 33 extends over the entire axial length of the protective cap 21 and corresponds to the radially centered recess 32 already mentioned, which is also designed to communicate with a pocket 36 for receiving the blade 7. In this respect, the pocket 36 is designed depending on the shape of the blade 7 and has a Fig. The protective cap 21 has a rectangular base shape. Furthermore, as already mentioned, the recess 32 of the protective cap is designed to receive the guide wire 10, which extends 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.

[0061] Fig. Figure 24 shows the protective cap 21 of the Fig. 23 in a top view of its upper area 29, showing the slot 33, the recess 32 and the projection 18. Fig. Figure 25 shows the protective cap 21 in a distal view, from which the slot 33 and the recess 32 are also visible. Fig. Figure 26 shows the protective cap 21 in a view from below and therefore in particular the widening lower area 28.

[0062] Fig. Figure 27 shows the base body 2 connected to the protective cap 21 according to Fig. 5 in a top view of its upper area 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 locking projections 37, 38 already mentioned engaging in it. Fig. Figure 28 shows the cutting instrument 1 of the Fig. 27 in a view from below of its lower area 28.

[0063] The Fig. 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.

[0064] First, according to Fig. 29 A hollow needle 42 was inserted to the intervention site to create access. The hollow needle 42 has a beveled distal end 43 and a proximal handle 44. A [missing information] is inserted into the hollow needle 42. Fig. 29. A stylet, covered from a perspective by the hollow needle 42, is inserted, its distal end face aligning 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 treatment site. 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 intervention site, the diameter of the guide wire 10 being adapted to the lumen of the cylindrical cavity of the hollow needle 42. Subsequently, according to 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, which in Fig. Figure 33 shows that the cutting instrument 1 is moved further distally along the guide wire 10 to the tissue 25 to be processed, as also described in the figures already shown. Fig. 6 and Fig. 7 is shown. As in connection with Fig. 8 is described according to Fig. 34 The protective cap 21 is pulled distally away from the base body 2, so that the blade 7 of the cutting instrument 1 is exposed. The protective cap 21 is removed according to Fig. 35, similar to Fig. 9, now removed 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 guided further distally, so that the in Fig. 35 tissues (not shown) are processed and spread distally by the continued insertion of the cutting instrument 1. A working sleeve (not shown) is then inserted over the cutting instrument 1 to the actual treatment site, whereupon the cutting instrument 1 is removed proximally, so that a working instrument and / or an endoscope can now be inserted over the working sleeve to the treatment site and processed there. After completion of the treatment at the treatment site, the instruments are again removed proximally from the treatment site.

[0065] The Fig. Figures 36 to 42 show the use of cutting instrument 1 in a surgical procedure on the spine, similar to that in connection with the Fig. 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 basically correspond to the steps of the interlaminar approach already described according to the Fig. 29 to 35: Insertion of the hollow needle 42 with inserted stylet - via the transforaminal approach - to the intervention site ( Fig. 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 ( Fig. 37), removal of the hollow needle 42 proximally ( Fig. 38), Inserting the cutting instrument 1 with the protective cap 21 attached from proximal over the guide wire distally ( Fig. 39 and Fig. 40), Pulling off the protective cap 21 distally ( Fig. 41), removal of the protective cap 21, lateral and distal movement of the cutting instrument while working and simultaneous spreading of the tissue not shown 25 ( Fig. 42). The subsequent insertion of the working sleeve, the working instrument and / or the endoscope to treat the procedure site and the subsequent removal of the instruments from the procedure site are not shown.

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) at a distal end region (3) and which has a distally oriented cutting edge (15), wherein the blade (7) extends distally beyond the base body (2), characterized by , 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 by , 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 by , that the blade (7) has a distal blade tip (14). [4] Medical cutting instrument (1) according to any one of claims 1 to 3, characterized by , 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 any one of claims 1 to 4, characterized by , that the cutting edge (15) of the blade (7) defines a blade plane (13), 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 any one of claims 3 to 5, characterized by , 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 any one of claims 3 to 6, characterized by, 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 by , that the cutting edge (15) extends from the distal blade tip (14) 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 any one of claims 6 to 8, characterized by , 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 any one of claims 6 to 9, characterized by, 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 any one of claims 1 to 10, characterized by , that at least one transition of the blade (7), in particular from its cutting edge (15), to the base body (2) is designed to be edge-free. [12] Medical cutting instrument (1) according to any one of claims 1 to 11, characterized by , 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 height of the lumen (9) of the base body (2). [13] Medical cutting instrument (1) according to any one of claims 1 to 12, characterized by , that the blade (7) is connected to the base body (2) by form and / or force and / or material connection. [14] Medical cutting instrument (1) according to any one of claims 1 to 13, characterized by , 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 any one of claims 1 to 14, characterized by , that the base body (2) widens from the distal frontal face (5) proximally, in particular conically. [16] Medical cutting instrument (1) according to claim 15, characterized by , 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 any one of claims 1 to 16, characterized bya protective cap (21) which is detachably connectable to the base body (2), wherein in particular it is provided that the protective cap (21) has an interior 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 detent 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 by , 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 any one of claims 17 to 19, characterized by, 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 any one of claims 18 to 20, characterized by , that the protective cap (21) is designed to widen proximally from its distal front face (27), in particular in an area (28) associated with the blade (7). [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 using a medical cutting instrument (1) according to any one of claims 1 to 21, in particular using 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) processes the tissue (25), wherein the medical cutting instrument (1) is guided further distally and wherein, in particular, the processed tissue (25) spreads due to the geometry of the medical cutting instrument (1), - Inserting a working sleeve over the cutting instrument (1) to the intervention site, - Removal of the cutting instrument (1) proximally, - Inserting a surgical instrument and / or an endoscope to the site of the procedure and working on the site of the procedure. [24] Method according to claim 23, characterized by, that the medical cutting instrument (1) is fitted 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).

Images