Medical guide instrument, medical instrument set, medical device, and medical method

Abstract

The invention relates to a medical guide instrument for a medical electrode (20) in order to position the latter against spinal nerves in a spinal canal. The guide instrument has a distal feed tube (38) for receiving the electrode, wherein when the guide instrument is in an insertion position a first portion of the feed tube has a curvature, while when the guide instrument is in a feed position the first portion of the feed tube is substantially linear. The invention further relates to an instrument set having the guide instrument and an electrode, and to a medical device having the guide instrument and an endoscope. The invention finally relates to a method for positioning the medical electrode against spinal nerves.

Description

[0001]Medical guidance instrument, medical instrument set, medical device, and medical method. The invention relates to a medical guidance instrument for a medical electrode for positioning the electrode on spinal nerves in a spinal canal, in particular on spinal nerve nodes. Furthermore, the invention relates to a medical instrument set, a medical device, and a medical method. Spinal cord stimulation has become an important pillar of chronic pain therapy in recent decades. From this, the stimulation of the dorsal root ganglia, i.e., spinal nerve nodes, has emerged as a new technique for treating, in particular, monoradicular pain of the upper and lower extremities, especially of peripheral origin.Stimulation of the dorsal root ganglion is a new, effective form of therapy for pain conditions affecting one or more different nerve roots. Common procedures involve implanting the electrode in the patient's spinal canal via the intralaminar approach. The electrodes are advanced (epidurally) into the patient's spinal canal as far as the desired dorsal root ganglion. However, this is often difficult in patients with epidural scarring, which blocks electrode movement and often causes undesirable deflection, especially since the electrode is designed to be flexible due to its use in contact with the dorsal root ganglion. Especially for this patient group, reliable and rapid placement of the electrode at the desired location is not possible with current devices and procedures.It is therefore the object of the invention to eliminate the disadvantages of the prior art and in particular to enable better positioning of the electrode. The object of the invention is achieved with a medical guiding instrument of the type mentioned at the outset, wherein the guiding instrument has a distal feed tube for receiving the electrode, wherein in an insert position of the guiding instrument a first section of the feed tube has a curvature and wherein in a feed position of the guiding instrument the first section of the feed tube is essentially linear. The object of the invention is further achieved with a medical instrument set with a medical guiding instrument according to the invention and with a medical electrode with at least one electrically conductive contact surface and with a lead connected to the electrode.Furthermore, the invention is achieved with a medical device having a medical guiding instrument according to the invention and with a medical endoscope, wherein the guiding instrument can be received in a working channel of the endoscope. Finally, the invention is achieved with a medical method for arranging a medical electrode on spinal nerves using a medical guiding instrument according to the invention, comprising the following steps: providing access to the spinal nerves, inserting the medical guiding instrument in the feed position for arranging the electrode on the spinal nerves, triggering the deployment position of the medical guiding instrument, and inserting the electrode through the medical guiding instrument through its feed tube until the electrode is arranged on the nerves.The invention is based on the fundamental idea that the guiding instrument according to the invention ensures reliable guidance of the medical electrode, particularly within the patient's body during the surgical procedure. In particular, the patient's epidural scar tissue, which often causes undesired deflection of the electrode with known guiding instruments, can be overcome by the defined guidance of the electrode by the guiding instrument according to the invention in the deployment position, so that the electrode reaches its intended location safely and quickly and the planned pain therapy can be continued. For the purposes of the invention, the deployment position of the guiding instrument refers to a position in which the electrode can be pushed through the guiding instrument and reach a predefined location.According to the invention, this is achieved by the feed tube being curved at its first section. In the feed position, the guide instrument can be positioned particularly easily at a predetermined location, particularly due to the linear design of the feed tube in the feed position. In the feed position, the first section of the feed tube can be coaxial, whereby coaxial in the sense of the invention refers to the (axial) extension direction of the feed instrument according to the invention. According to the invention, a distal direction points towards the patient, a proximal direction points towards the user / surgeon. In the sense of an imaginary three-dimensional cylindrical coordinate system, an axial direction is aligned with the extension direction of the feed instrument, while a radial direction is perpendicular to the axial direction, as is a circumferential direction.The delivery tube of the guide instrument can be designed, in particular, as a flexible (hollow) catheter, with at least one (hollow) cylindrical section. In the deployed position of the guide instrument, the curvature of the first section of the delivery tube can be user-defined, in particular user-variable, preferably manually adjustable. The curvature of the delivery tube in the deployed position of the guide instrument can have a predefined axis of curvature and / or a predefined radius of curvature, wherein the radius of curvature is in particular between 6 mm and 15 mm, preferably between 9 mm and 12 mm. In particular, the axis of curvature is perpendicular to the axial direction and / or is arranged in a horizontal plane.The first section is preferably arranged in a distal region of the feed tube, for example as a distal end region, in order to specifically deflect the electrode as immediately as possible after it emerges from the guide instrument. The distal end region is preferably designed to be flexible. A change between the feed position and the use position of the guide instrument can be carried out due to a particularly linear displacement of the feed tube in order to change structurally easily between the feed position and the use position of the guide instrument. The guide instrument preferably has at least one actuator by means of which the use position and in particular the feed position of the guide instrument can be assumed. To facilitate operability, the actuator preferably has at least partially a knurling on a surface facing the user.The actuator can be manually operable and / or designed to be linearly movable and / or rotatable. The feed tube can be linearly movable by means of an actuator in order to be able to assume its use position and / or its feed position. In an advantageous embodiment of the invention, the actuator is designed as a carriage, in particular as a linear carriage, in order to enable a particularly simple change from the feed position of the guide instrument to its use position. For this purpose, the actuator can be guided as a slide in a recess in the feed tube assigned to it, which is designed in particular as an elongated hole. Preferably, the actuator is connected at least indirectly to the feed tube, in particular directly and / or positively, so that in particular an axial movement of the feed tube can occur through actuation of the actuator.For the particularly direct positive connection of the actuator to the feed tube, the actuator preferably has at least one projection directed towards the feed tube, which engages positively in at least one, particularly radial, recess of the feed tube. Alternatively, the actuator can have a recess into which a projection of the feed tube directed towards the recess engages. The actuator can be assigned to a guide part, which is particularly positively connected to a proximal handle part, in particular screwed thereto. The design of the guide part and the handle part enables a functional-spatial division of the guide instrument, in which, within the meaning of the invention, the handling of the guide instrument can be carried out by the handle part and the actuation of the deployment position of the guide instrument can be carried out by the guide part. The handle part can be detachably connected to the guide part.The feed tube preferably has at least one linear, in particular coaxial section, the length of the linear section being in particular between 250 mm and 350 mm. The linear section is in particular rigid, so that it is also linear, especially in the deployment position of the guide instrument. Alternatively, the linear section can be flexible. The feed tube is preferably made of one piece. In this embodiment, the feed tube can consist of several components, which are, however, connected in one piece, in particular welded to one another. In an alternative embodiment, the feed tube can be made of several parts, in particular two parts, wherein a first distal part of the feed tube can comprise the first section which can be bent within the meaning of the invention.A second, proximal part of the feed tube can in particular comprise the linear section, which extends, for example, over at least 75% of the total length of the feed tube. The first part of the guide tube can be positively connected to its second part, for example by means of a particularly rectangular recess in the first part, into which a complementarily shaped elevation of the second part engages, so that a positive connection is formed between the first part and the second part of the feed tube along the direction of extension of the feed tube. In the sense of the invention, the first part of the feed tube can also be welded integrally to its second part. The second part of the feed tube can in particular have the aforementioned recess for the positive connection to the actuator. At least one part of the feed tube can have a component made of plastic or consist of such a component.In an advantageous embodiment, the guide instrument can be in the deployment position independently without the application of external force. This is achieved, for example, by the feed tube having, at least in sections, particularly in the region of the first section, at least one component made of an elastic material, such as a shape memory alloy, in particular a nickel-titanium alloy, for example nitinol, and / or a plastic, in particular polyethylene (PE). The feed tube can be surrounded, at least in sections, particularly in a distal region, by a particularly rigid guide tube, wherein the guide tube is designed, for example, as a hollow cylinder and / or is aligned parallel to the feed tube, in particular coaxially to it.The length of the guide tube corresponds in particular to the length of the linear section of the feed tube, wherein the axial length of the guide tube is preferably between 250 mm and 350 mm. The feed tube and / or the guide tube preferably have a circular cross-section with in particular a diameter between 3 mm and 4 mm, preferably 3.5 mm. In an advantageous development of the invention, the feed tube is arranged with a tight fit within the guide tube, wherein the feed tube is in particular axially movable relative to the guide tube. The guide tube can at least partially have components made of metal, preferably stainless steel, and / or an elastic material, preferably plastic. To guide the medical electrode, the guide instrument preferably has an internal bore for receiving the electrode, wherein the internal bore extends in particular over the entire axial length of the guide instrument.The inner bore is in particular coaxially aligned. The guide instrument is in particular reusable or alternatively designed as a disposable instrument. In particular, when the guide instrument is designed as a disposable instrument, the feed tube can be made of plastic. In a further advantageous embodiment of the invention, the feed tube is connected to the actuator at least indirectly via a pull wire. For example, a proximal end region of the feed tube and / or an upper side of the feed tube are connected to the pull wire. The pull wire can be connected to an abutment. Preferably, the actuator, which is in particular designed as a slide, is connected to an abutment.The feed tube and / or the guide tube can have an elliptical cross-section, wherein the diameter of the feed tube and / or the diameter of the guide tube in a first semi-axis of the cross-section is preferably between 2.5 mm and 3.5 mm and in a second semi-axis of the cross-section between 1.5 mm and 2 mm, in particular 1.7 mm. The guide instrument can have a flattened area on its outer surface, in particular in an area facing the actuator, which flattened area extends in particular over an azimuthal angle range between 30° and 90°. The flattened area creates a defined position for the guide area when it is placed on an operating table, for example. This prevents accidental dropping and thus contamination of the guide instrument. In a further advantageous embodiment of the invention, the guide instrument is designed as a disposable instrument.The first section of the feed tube can be arranged in an axially central section so that improved guidance of the electrode in the patient's spinal canal is possible. An adapter part with an internal bore for receiving the electrode is preferably provided in order to simplify the insertion of the electrode into the guide instrument. Further preferably, the feed tube at least partially extends through the adapter part in order to further improve the insertion of the electrode. The internal bore in particular has a circular cross-section and / or is coaxially aligned. The adapter part is preferably arranged in a proximal region of the guide instrument or in the distal guide part of the guide instrument. The guide part can have a handle in order to improve the operability of the guide instrument. The adapter part can in particular be arranged at the axial height of the handle part.The inner bore of the adapter part is preferably radially widened towards the proximal end face and / or the distal end face of the adapter part. In particular, the inner bore can be continuously widened towards one of the end faces, resulting, for example, in a funnel-shaped configuration of the inner bore. The inner bore of the adapter part preferably has a lateral connection piece arranged at a finite angle to the longitudinal axis of the guiding instrument, said connection piece having an inner bore for receiving the electrode, wherein the inner bore of the connection piece is connected to the inner bore of the adapter part. In this way, for example, the electrode can be inserted into the inner bore of the adapter part at a finite angle other than 0°, such that the axial view of the guiding instrument is not impaired by the electrode.At least one component of the guide instrument is, for example, X-ray visible in order to be able to determine the current position of the guide instrument during the surgical procedure. The guide instrument, in particular a body part thereof, can have at least one preferably coaxially aligned bore in order to reduce the weight of the guide instrument according to the invention and to guarantee its easier applicability, in particular during longer periods of use. The at least one electrically conductive contact surface of the electrode of the instrument set can be formed in particular in a distal region of the electrode. The electrode is preferably cylindrical and in particular has at least two, preferably eight contact surfaces, which are arranged axially one behind the other, for example. The electrode can have a maximum of 16 contact surfaces.An electrically non-conductive insulating surface can be arranged between two electrically conductive contact surfaces in order to prevent short circuits. At least one section, in particular a distal section, of the line electrically connected to the electrode can be elastic and / or at least one section of the line can be rigid. In this way, the electrode and / or the line electrically connected to the electrode can adapt in particular to the first section of the feed tube which is curved in the deployment position of the guide instrument. The electrode and / or the electrical line have a cylindrical shape with an outer diameter of, for example, between 0.5 mm and 1.5 mm. The length of the line is preferably between 400 mm and 800 mm.The electrode can be connected to an electrical pulse generator, wherein in particular the contact surfaces of the electrode can be controlled independently of one another by the pulse generator. The medical device has in particular the medical instrument set with the medical guiding instrument according to the invention and / or can be further developed such that the guiding instrument, in particular its feed tube and / or the guide tube of the guiding instrument, can be received in the working channel of the endoscope. The endoscope can have a flushing connection and / or an optical imaging device, in particular a camera. In particular, the endoscope is designed as a disposable instrument for single use and / or has at least one disposable component. In an alternative development of the invention, the endoscope is designed to be reusable.The method according to the invention can be carried out with a medical guiding instrument according to the invention and / or with a medical instrument set according to the invention and / or with a medical device according to the invention. In a further development of the method according to the invention, the access to the spinal nerves, in particular epidural access, is carried out transforaminally, i.e. through an intervertebral foramen as a (lateral) intervertebral foramen between two adjacent vertebral bodies and / or intralaminarly, i.e. through an intralaminar window on the back (anterior) between two adjacent vertebral bodies. The medical guiding instrument can be inserted by inserting a medical device according to the invention. In addition, the medical guiding instrument can be inserted under optical visual control and / or under X-ray control.The electrode can be arranged on a nerve ganglion, in particular on a dorsal nerve ganglion of the spinal nerves, to ensure effective application of current pulses. After insertion, the electrode can be connected to an electrical pulse generator and, in particular, the remaining components of the medical guiding instrument and / or the medical device can then be removed from the surgical site. Preferably, the electrode can be arranged on the spinal nerves, for example, connectable by means of loops and / or anchor elements. Further advantages and features of the invention emerge from the claims and from the following description, in which exemplary embodiments of the invention are explained in detail with reference to the drawings. In the drawings: Fig. 1 shows a first embodiment of a guiding instrument according to the invention in a side view, Fig. 2 shows the guiding instrument according to Fig.1 in a plan view, Fig. 3 the guide instrument according to Fig. 1 in an axial longitudinal section, Fig. 4 the guide instrument according to Fig. 1 in a cross section, Fig. 5 a detailed view of Fig. 4, Fig. 6 an enlarged view of a feed tube, Fig. 7 the guide instrument according to Fig. 1 in a feed position, Fig. 8 the guide instrument according to Fig. 7 in an insert position, Fig. 9 the guide instrument according to Fig. 8 with an inserted electrode, Figs. 10, 11 a further embodiment of the feed tube in an insert position, Fig. 12 a further embodiment of the feed tube in an insert position, Fig. 13 the electrode of Fig. 9 in a complete view, Fig. 14 the guide instrument of Fig. 9 in an insert position with inserted electrode and with an endoscope, Fig. 15 an enlarged view of Fig. 14 in the area of ​​the distal Feed tube, Fig. 16 the guide instrument with endoscope according to Fig.14 in a perspective proximal view, Fig. 17 the guide instrument according to the invention in a second embodiment in a side view, Fig. 18 the guide instrument according to Fig. 17 in a top view, Fig. 19 the guide instrument according to Fig. 17 in an axial longitudinal section, Fig. 20 the guide instrument according to Fig. 17 in a perspective view from distal below, Fig. 21 the guide instrument according to Fig. 17 in a feed position, Fig. 22 the guide instrument according to Fig. 21 in an insert position with an electrode to be inserted, Fig. 23 the guide instrument according to Fig. 22 with an inserted electrode, Fig. 24 the guide instrument according to Fig. 17 in an insert position with an endoscope, Fig. 25 an enlarged view of the guide instrument according to Fig. 24 in the area of ​​a distal feed tube, Fig. 26 the guide instrument with endoscope according to Fig. 24 in a perspective, proximal view, Fig.27 shows a third embodiment of the guiding instrument with endoscope according to the invention in a side view, Fig. 28 shows the guiding instrument with endoscope according to Fig. 27 in a perspective proximal view and Fig. 29 shows an implanted electrode with pulse generator in a proximal view. Fig. 1 shows a side view of a guiding instrument 10 according to the invention in a first embodiment with a proximal body part 11, an axially central handle part 12 and a distal guide part 13. The proximal body part 11 is essentially designed as an axially aligned hollow cylinder with an inner bore 14 and an axial base 15 arranged within this, which is shown in particular in the longitudinal section of Fig. 3. On its upper surface 16, the body part 11 according to Fig.2 has a recess 17 with a partially circular cross-section, which is surrounded on both sides by a flattened portion 16a with a flat surface, so that the guide instrument 10 does not fall uncontrollably from a cutlery table after it has been placed down, but rather remains in a defined position. The body part 11 is open towards its proximal end face 18 so that an adapter part 19 for inserting an electrode 20 can be inserted into the inner bore 14 and connected to the body part 11. When connected, the adapter part 19 engages the proximal bore 14 of the body part 11 and projects proximally beyond it. The distal outer diameter of the adapter part 19 is smaller than the inner diameter of the body part 11. The adapter part 19 has an axially continuous inner bore 21, which is radially widened towards the proximal end face 22 of the adapter part 19 in order to facilitate the insertion of the electrode 20.The inner bore 21 of the adapter part 19 is also widened towards its distal end 23 to facilitate the insertion of a feed tube 38, which is described further below. In the illustrated embodiment, the electrode 20 has an outer diameter of 1.4 mm. The diameter of the inner bore 21 is slightly larger than the diameter of the electrode 20 to be inserted, so that the latter can penetrate the inner bore 21 and is freely movable axially therein, which is also described further below. The proximal body part 11 of the guiding instrument 10 is connected in the distal direction to the handle part 12, with a distal, cylindrical pin 24 of the body part 11 engaging in an inner bore 25 of the handle part 12. The handle part 12 is designed, similar to the body part 11, as an axially aligned cylinder with a according to the top view of Fig.2 upwardly facing, elongated hole-shaped recess 26, which opens into the inner bore 25 of the handle part 12. The recess 26 serves as a guide for an actuator 27 arranged partially within the recess 26, which, in the embodiment according to Figs. 1 to 6, is designed as a manually operable linear slide 28 as a slider, in order to move the guide instrument 10, in particular, from a feed position into an insert position, which is described further below. The linear slide 28 has a semicircular slide button 30 with a grooved surface 31 on its upper side 29 shown in Fig. 1 to improve operability. On its underside 32 according to Fig. 1, the linear slide 28 has two rectangular projections 33 shown in the longitudinal section of Fig. 3, which penetrate the recess 26 and the inner bore 25 of the handle part 12 such that the projections 33 project beyond the handle part 12, see Figs. 1 and 3.The cross-section of the handle part 12 tapers towards its distal end face 34, while the cross-section of the inner bore 25 in the distal region 35 of the handle part 12 remains unchanged. The distal guide part 13 has a rigid guide tube 36 made of stainless steel, which, coming from the distal direction, is inserted into the inner bore 25 of the handle part 12 and connected thereto. In the illustrated embodiment of the guide instrument 10 according to Figs. 1 to 6, the region of the guide tube 36 projecting distally beyond the handle part has an axial length l. FRbetween 250 mm to 350 mm, measured from the distal end face 34 of the handle part 12 to the distal end face 37 of the guide tube 36. The guide tube 36 is designed as a hollow cylinder with a circular cross-section, wherein the diameter of the guide tube is 363.50 mm and remains unchanged over its axial length. In particular, according to the section in Fig. 3, a feed tube 38 is arranged within the guide tube 36, the axial length of which is greater than that of the rigid guide tube 36. The feed tube 38 engages in an interior space 39 of the guide tube 36, the inner bore 25 of the handle part 12, the bore 14 of the body part 11 and the inner bore 21 of the adapter part 19, wherein in the operating position of the guide instrument 10 shown in Fig. 3, the proximal end face 40 of the feed tube 38 is arranged within the inner bore 21 of the adapter part 19 and does not completely penetrate it.The outer diameter of the feed tube essentially corresponds to the inner diameter of the inner bore 21 of the adapter part 19, so that the feed tube 38 is arranged with a tight fit within the adapter part 19, but is axially movable therein. In particular, at its distal end region 41, the feed tube 38 has components made of a shape memory alloy, so that the distal end region 41 of the feed tube 38 is designed to be flexible. In the exemplary embodiment of Figs. 1 to 6, which show the guide instrument according to the invention in the deployed position, the distal end region 41 of the feed tube 38 has a curvature oriented upwards in Fig. 1, which is approximately 90° relative to the orientation of the guide tube 36, so that the distal end face 42 of the feed tube 38 is deflected upwards by approximately 9 mm to 12 mm from the lower, distal end face 37 of the guide tube 36. This corresponds to a radius of curvature of 9 mm to 12 mm.In this respect, in the exemplary embodiment shown, the curved distal end region 41 of the feed tube 38 corresponds to its first section 41 within the meaning of the invention. Fig. 6 shows a detailed view of the flexible distal end region 41 of the feed tube 38. Accordingly, the region 41 shown is provided with a plurality of recesses 42a, which enable elastic deformation of the feed tube 38, here: the curvature shown, in the use position. The inner diameter of the feed tube 38 is slightly larger than 1.40 mm, so that the electrode 20 with its outer diameter of 1.40 mm can be pushed axially through the feed tube 38 and is axially movable within the feed tube 38. In particular, according to Fig.3 to 5 it can be seen that the projections 33 of the sliding button 30, which are directed downwards there, engage in axially aligned, lateral recesses 42b of the feed tube 38, so that the sliding button 30, and thus the linear slide 28 as a whole, are positively connected to the feed tube 38 in the sense of a quickly dismantled locking connection. Fig. 4 shows a cross-section through the guide instrument 10 according to Fig. 3 at the axial height of the linear slide 28. Fig. 5 is a radially centered detailed view of Fig. 4. The projections 33 of the sliding button 30, which in particular extend through the recess of the handle part 26, are each subjected to a laterally outwardly directed force and thus serve as snap hooks with which the sliding button 30 is clamped, i.e. non-positively connected, to the handle part 12. If the sliding button 30, starting from the position according to Fig.3, is moved by a user in the proximal direction, the feed tube 38 follows this axial movement. As a result, the distal end face 42 of the feed tube 38 is retracted into the guide tube 36, so that the feed tube 38, due to its geometry and its elastic design, is arranged completely and coaxially within the guide tube 36. The proximal end face 40 of the feed tube 38 remains within the inner bore 21 of the adapter part 19. This configuration corresponds to the feed position of the guide instrument 10 according to the invention and is shown in Fig. 7. Now, starting from the feed position of the guide instrument 10 according to Fig.7 the sliding button 30 is moved in the distal direction, the elastic feed tube 38 penetrates the distal end face 34 of the rigid guide tube 36 and, after emerging from the guide tube 36, assumes its already described curvature due to the shape memory alloy of the distal end region 41, see Fig. 8. This configuration corresponds to the deployment position of the guide instrument 10. If, in the deployment position of the guide instrument 10, the electrode 20 with an electrical line 43 connected thereto is inserted from the proximal side through the adapter part 19 into the interior 39 of the feed tube 38 and moved further distally, the electrode 20 finally penetrates the distal end face 42 of the feed tube 38, which is angled relative to the axial direction due to the curvature, here at an angle of approx. 90°.This makes it possible to transport the flexibly designed electrode 20 to a desired location, which is not possible or only possible with great difficulty with the known rigid and straight-line instruments. Fig. 10 shows a two-part design of the feed tube 38, which has a first, distal part 38a and a second, proximal part 38b. The first part 38a is shown separately from the second part 38b in Fig. 10. The first part 38a has, as already described, the curved first section in the distal end region 41, which is provided with several material structures using a laser cutting process. Since no external forces act on the distal end region 41 of the feed tube 38 shown in Fig. 10, the tube automatically assumes the curved position, as also already described. The first part 38a is provided proximally with a groove shown in Fig.10 shown, in the sense of an opening. Extending proximally from the recess 38c is an axial, milled slot 38d, which has a smaller lateral extent than the recess 38c. The slot 38d extends from the rectangular recess 38c to a proximal end face 38e of the first part 38a. The first part 38a is designed as a hollow cylinder, at least in a region from the recess 38c to its proximal end face 38e. The second part 38b of the feed tube 38 has, on its distal side, a coaxially aligned, cylindrical extension 38f, which has a smaller diameter than the inner diameter of the first part 38a. The second part 38a can therefore be inserted into the first part 38a with its attachment 38f.For the positive connection of the second part 38b to the first part 38a, the extension 38f has a rectangular projection 38g in the form of an elevation, which is designed to complement the recess 38c of the first part 38a. The extension 38f is formed integrally with a body part 38h, the diameter of which corresponds to the diameter of the first part 38a. The body part 38h has a recess 38i in its proximal region, through which the rectangular projections 33 of the actuator 27 can engage in order to positively connect the actuator 27 to the feed tube 38. By pushing the second part 38b in the direction of the first part 38a, starting from the representation according to Fig. 10, the projection 38f penetrates the first part 38a until the projection 38g is at the same axial height as the recess 38c, so that the former penetrates the latter.The material weakening in the form of the slot 38d of the first part 38a facilitates the insertion of the parts 38a, 38b into one another. The positive engagement of the projection 38g in the recess 38c creates a removable connection between the two parts 38a, 38b in the sense of a snap-in connection, so that the feed tube 38 as a whole is movable, in particular axially. This state is shown in Fig. 11. Figs. 10 and 11 essentially show the implementation of the connection of the parts 38a, 38b by means of a positive connection. The positive connection is secured by the guide tube 36 (not shown in Fig. 10) in such a way that, after the feed tube 38 has been inserted into the guide tube 36, a reliable connection is ensured during use, even under mechanical stress. Fig. 12 shows an alternative design of the feed pipe 38, which is designed in one piece.This eliminates the need to connect two independent parts 38a, 38b to one another, resulting in a structurally simple design. The connection of the feed tube 38 to the feed tube 36 pushed over it is made by means of the recess 38i, as already described above. Fig. 13 shows the electrode 20 with the electrical line 43 connected proximally to the electrode 20 and an electrical pulse generator 44 connected to the line, here a pacemaker, which provides the electrical energy to control the electrode 20. In the embodiment of Fig. 13, the electrode 20 is cylindrical and has on its outer surface 45 six electrically conductive contact surfaces 46 arranged axially one behind the other, by means of which the current pulses can be applied in a spatially targeted manner. An electrically non-conductive insulation 46a is provided between each two contact surfaces 46.Each contact surface 46 can be controlled separately by the pulse generator 44, the current pulses being predefined in terms of amplitude and frequency. The electrode 20 is elastic and is shown in a curved arrangement in Fig. 13. In the exemplary embodiment in Fig. 13, the electrode 20 is shown in a flexible configuration. Fig. 14 shows a medical device 49 with the guiding instrument 10 according to the invention, essentially in the configuration according to Figs. 1 and 2, an electrode 20 inserted therein together with electrical lead 43, and with an endoscope 50 in surgical use. Accordingly, the guide tube 36 of the guiding instrument 10 is inserted into a coaxially aligned working channel 51 of the endoscope 50.The endoscope 50 accesses the spinal canal 54 of a patient via a distal, rigid working sleeve 52 of the endoscope 50, wherein the working sleeve 52 does not project distally beyond the guide tube 36 and the feed tube 38, together with the electrode 20, which is not shown in Fig. 14 due to perspective reasons. In Fig. 14, the guide tube 36 of the guiding instrument 10, together with the feed tube 38, is inserted through an intervertebral foramen 53, i.e. an intervertebral foramen as access to the spinal canal 54 of the patient between two adjacent vertebral bodies, here two lumbar vertebral bodies 55, in order to bring the electrode 20 into contact with a dorsal root ganglion (not shown in Fig. 14) within the spinal canal 54. Unlike the design shown in Figs. 1 and 2, the body part 11 of the guide instrument does not have a recess 17, but rather only the flattened portion 16a on its upper side. The guide instrument 10 is located in Fig.14 in the deployment position, so that the distal end region 41 of the feed tube 38 is curved in the manner already described, which is shown in particular in the detailed view of Fig. 15. The electrode 20 passing through the feed tube 38 is deflected according to the curved distal end region 41. In addition, according to Fig. 15, the working sleeve 52 is distally cannulated. According to Fig. 14, the endoscope 50 has a lateral irrigation connection 57 and a lateral optical output 56, the latter allowing visual inspection of the surgical area. Fig. 16 shows the medical device 49 of Fig. 14 in a perspective, cranioproximal view, wherein access to the spinal canal 54 is via an intralaminar window 58 between the two lumbar vertebrae 55. In Fig. 16, the guiding instrument 10 is also in the operating position; the electrode 20 is inserted into the spinal canal 54 by approximatelyCurved upwards by 90° and is located in contact with the dorsal nerve ganglion, not shown in Fig. 16. Fig. 17 shows a second embodiment of the guide instrument 10 according to the invention, which is designed as a disposable instrument for single use. The guide instrument 10 has a proximal handle part 59 that is positively connected to a distal guide part 60. The proximal, outer contour of the handle part 59 is designed to be securely enclosed and held by the hand of a user, especially during operation. The actuator 27 is provided in a distal region 59a of the handle part 59 and, similar to the first embodiment of the guide instrument 10, is designed as a linear slide 28 with a sliding knob 30, wherein the sliding knob 30 is also provided with a profile here. The linear slide 28 is located as shown in Fig.17 to 20 in a proximal position corresponding to the deployment position of the guide instrument 10, in which the first distal section 41 of the feed tube 38 is angled. According to Fig. 17, the distal guide part 60 has a connection piece 61 pointing downwards to the right with an internal bore 62, which serves as a lateral feed channel, which is also evident from the axial longitudinal section of Fig. 19. The diameter of the inner bore 62 is designed such that an electrode 20 shown in Fig. 17 can be inserted into the inner bore 62 with lateral play, see also Fig. 19. The inner bore 62 of the connecting piece 61 is connected to a coaxial inner bore 63 of the guide part 60, so that the electrode 20 can finally be inserted via the inner bores 62, 63 into the interior 39 of the feed tube 38, wherein the feed tube 38 is connected to the guide part 60.The feed tube 38 has an elliptical cross-section and has a diameter of between 2.50 mm and 3.50 mm in the lateral, horizontal direction, corresponding to a first semi-axis, and a diameter of 1.70 mm in the lateral, vertical direction, corresponding to a second semi-axis. In this embodiment, the feed tube 38 has a second, rigid section 64 with an axial length l. ZRbetween 250 and 350 mm and the already described first, curved section 41 with a curvature of approximately 90°. From the longitudinal section of the guiding instrument 10 according to Fig. 19, it can be seen that the linear slide 28 is mounted for linear movement on a distal contact surface 65 of the handle part 59. The contact surface 65 has a stop 67 at its distal end region 66 for the distal movement of the linear slide 28. Proximally, the linear slide 28, according to Fig. 19, rests against an abutment 68, which in turn rests against a proximal end face 69 of the recess 26 of the handle part 59. The abutment 68 is connected to a coaxially aligned pull wire 70 which passes through the recess 26 of the handle part 59 and the inner bore 63 of the guide part 60 and is connected to an upper side 71 of the feed tube 38.If the linear carriage 28 is moved by a user from a distal position in a proximal direction, the resulting tension on the pull wire 70 causes a deflection of the upper side 71 of the feed tube 38 connected to the pull wire 70, so that its distal end region 41 assumes the curved position shown in Fig. 19. In this position, an electrode 20 inserted into the lateral inner bore 62 of the guide part 60 is deflected accordingly upon further axial movement through the distal end region 41 of the feed tube 38. Fig. 20 shows the guide instrument 10 of Fig. 19 in the deployed position in a disto-caudal view. Fig. 21 shows the guide instrument 10 of Fig. 17 in the feed position, in which the linear slide 28 is in a distal position, wherein the distal end region 41 of the feed tube 38 is coaxially aligned.During a proximal movement of the linear slide 28, the abutment 68 resting thereon is also moved in the proximal direction, causing the pull wire 70 to follow this movement. As already described, the pull wire 70 is connected to the upper side 71 of the feed tube 38, so that the distal end region 41 of the feed tube 38 is erected by the movement of the linear slide 28, see Fig. 22, which shows the guide instrument 10 in the deployed position. The electrode 20 inserted into the connection piece 61 will eventually emerge from the distal end face 42 of the feed tube 38 with continued axial movement, as shown in Fig. 23. Fig. 24 shows, similar to Fig. 14, the device 49 according to the invention with the guide instrument 10 in the second embodiment with the endoscope 50, the embodiment of which has already been discussed in connection with Fig. 14.The guide instrument 10 is inserted in a known manner into the working channel 51 of the endoscope 50, which is also evident from the detailed view of Fig. 25. There, the feed tube 38 emerges from the cannulated working sleeve 52, with the distal end region 41 being curved according to the insertion position of the guide instrument 10. According to Fig. 24, the device 49 shown, similar to Fig. 14, is inserted through the intervertebral foramen 53 in order to position the electrode 20 in the spinal canal 54. In Fig. 26, the device 49 according to the invention of Fig. 25 is arranged in the spinal canal 54 via the intralaminar access through the intralaminar window 58, similar to Fig. 16. Fig. 27 shows a third embodiment of the medical guiding instrument 10 according to the invention, which is inserted into the spinal canal 54 via the intervertebral foramen 53. Similar to the two embodiments mentioned above, the guiding instrument 10 of Fig.27, the distal feed tube 38, wherein its curved first section 41 is not arranged as the distal end region, but in an axially central section 41a. The axially central section 41a is covered in perspective in Fig. 27 and is not shown. Due to the position of the first section 41, a distal part of the feed tube 38 also engages in the spinal canal 54. The body part 11 is designed as a disposable endoscope, wherein the electrode 20, including the line 43, and also the feed tube 38 are inserted via the coaxial working channel 51 of the endoscope. The optical output 56 is connected via a camera cable 72 to a connector 73 to a camera head cable (not shown). The working sleeve 52 of the endoscope passes, similarly to the illustration in Fig. 24, via the intervertebral foramen 53 into the spinal canal 54. By actuating the actuator 27, this reaches the position shown in Fig.27, so that the first section 41 of the feed tube 38 - arranged axially centrally here - is bent and the electrode 20 can thereby be arranged within the spinal canal 54 as shown. Fig. 28 shows the guiding instrument 10 of Fig. 27, wherein access to the spinal canal 54 is via the intralaminar window 58 already described. Fig. 28 also shows the axially central section 41a of the feed tube 28. After the electrode 20 has reached the desired location in the spinal canal, in particular is in contact with the dorsal nerve ganglion, and the effectiveness of the placement of the electrode 20 has been checked, the medical guiding instrument 10 and the remaining components of the device 49 can be removed. The lead 43 connected to the electrode 20 is then connected proximally to an electrical pulse generator 44 shown in Fig. 29, as already shown in Fig.13. The pulse generator 44 is designed for the periodic and continuous output of current pulses to the electrode 20 and can be implanted in the patient's body. For this purpose, the electrode 20 is arranged, for example, on a fascia (not shown) using known anchoring devices, with strain relief loops ensuring the stable hold of the electrode 20. The method according to the invention will be described below with reference to the first embodiment of the guiding instrument 10 according to the invention, as shown in FIGS. 1 to 9 and 13 to 16: First, access is created to the patient's spinal canal 54. This occurs, for example, via the intervertebral foramen 53 (Fig. 14) and / or via the intralaminar window 58 (Fig. 16). Alternatively or additionally, access can also be achieved transforaminally by puncturing a caudal part of the foramen with a spinal needle (not shown).A guide wire (not shown) is then placed, over which dilators of successively larger diameters are successively pushed in order to spread the tissue around the guide wire as atraumatically as possible. Finally, a working sleeve is inserted over the last dilator under constant X-ray control. The working sleeve 52 of the endoscope 50 has an internal bore through which the endoscope 50 is inserted. The endoscope 50, in addition to the irrigation connection 57 and the optical output 56, has the working channel 51 for receiving the guide instrument 10 according to the invention. The guide instrument 10 is pushed through the working channel 51 of the endoscope 50 in the feed position until its distal end region 41 engages the spinal canal 54. The first section 41 of the feed tube 38 of the guide instrument 10 is designed to be linear in order to enable rapid insertion into the patient's body.After the guide instrument 10 has reached the desired location, the user actuates the actuator 27, thus in the specific embodiment pushing the linear slide 28 from proximal to distal, whereupon the feed tube 38 is also pushed in the distal direction, so that the first section 41 of the feed tube 38 projects beyond the rigid guide tube 36 and, due to its material properties, assumes the curved position already described; the guide instrument is now in the operating position. In the next step, the electrode 20 together with the lead 43 is inserted from the proximal side into the guide instrument 10, more precisely into its adapter part 19, until the electrode 20 emerges at the distal end face 42 of the curved feed tube 38 and can thereby assume the desired position, where it is brought into contact with the dorsal nerve ganglion in the spinal canal 54, for example.After the electrode 20 has assumed the desired position and its correct function has been verified, the guide instrument 10 is withdrawn along with the endoscope 50, so that ultimately only the electrode 20 remains in the patient. The electrode 20 is connected proximally to an electrical pulse generator 44, which is ultimately implanted in the patient as previously described.

Claims

Claims 1. A medical guidance instrument (10) for a medical electrode (20) for positioning the electrode (20) on spinal nerves in a spinal canal (54), in particular on spinal nerve ganglia, wherein the guidance instrument (10) has a distal feed tube (38) for receiving the electrode (20), wherein in an operating position of the guidance instrument (10) a first section (41) of the feed tube (38) has a curvature and wherein in an insertion position of the guidance instrument (38) the first section (41) of the feed tube (38) is substantially linear.

2. A medical guidance instrument according to claim 1, characterized in that in the operating position of the guidance instrument (10) the curvature of the first section (41) of the feed tube (38) is user-defined, in particular user-defined and variable, preferably manually adjustable. 3.Medical management tool according to one of claims 1 or 2, characterized in that the.

1. The first section (41) is arranged in a distal region of the feed tube (38), in particular as a distal end region, preferably being flexibly designed.

4. Medical guidance instrument according to one of the preceding claims, characterized in that a change between the feed position and the deployment position of the guidance instrument (10) is possible due to a particularly linear displacement of the feed tube (38).

5. Medical guidance instrument according to one of the preceding claims, characterized in that the guidance instrument (10) has an actuator (27) by means of which the deployment position of the guidance instrument (10) can be assumed.

6. Medical guidance instrument according to claim 5, characterized in that the actuator (27) is at least indirectly connected to the feed tube (38), in particular directly and positively. 7.A medical guidance instrument according to one of the preceding claims, characterized in that the guidance instrument (10) is in the operating position independently without external force being applied.

8. A medical guidance instrument according to one of the preceding claims, characterized in that the feed tube (38) is at least partially surrounded by a guide tube (36), in particular a rigid one.

9. Medical guidance instrument according to any one of the preceding claims, characterized in that the guidance instrument (10) has an internal bore (14, 21, 25) for receiving the electrode (20), wherein the internal bore (14, 21, 25) extends in particular over the entire axial length of the guidance instrument (10).

10. Medical guidance instrument according to any one of claims 5 to 9, characterized in that the feed tube (38) is connected to the actuator (27) at least indirectly via a pull wire (70).

11. Medical guidance instrument according to any one of the preceding claims, characterized in that the guidance instrument (10) is designed as a single-use instrument.

12. Medical guidance instrument according to one of the preceding claims, characterized in that the first section (41) of the feed tube (38) is arranged in an axially central section (41a) of the feed tube (38). 13.Medical guidance instrument according to one of the preceding claims, characterized in that the guidance instrument (10) has a flattened surface (16a) on its outer surface (16).

14. Medical guidance instrument according to one of the preceding claims, characterized in that an adapter part (19) with an internal bore (21) for. The adapter part (20) is provided for receiving the electrode (20), wherein, in particular, the inner bore (21) of the adapter part (20) is radially widened towards the proximal end face (22) and / or the distal end face (23) of the adapter part (19).

15. Medical instrument set comprising a medical guide instrument (10) according to any one of claims 1 to 14 and a medical electrode (20) having at least one electrically conductive contact surface (65) and a conductor (43) connected to the electrode (20).

16. Medical instrument set according to claim 15, characterized in that the conductor (43) has at least one elastic section (48) and / or at least one rigid section (47). 17.Medical device (49) comprising a medical guide instrument (10) according to any one of claims 1 to 14, in particular a medical instrument set according to claims 15 or 16, and a medical endoscope (50), wherein the guide instrument (10) is receptacleable in a working channel (51) of the endoscope (50).

18. Medical method for positioning a medical electrode (20) on spinal nerves using a medical guide instrument (10) according to any one of claims 1 to 14, comprising the following steps: providing access to the spinal nerves, inserting the medical guide instrument (10) in the delivery position for positioning the electrode. (20) on the spinal nerves, triggering the deployment position of the medical guide instrument (10) and inserting the electrode (20) through the medical guide instrument (10) through its feed tube (38) until the electrode (10) is positioned on the nerves.

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