MEDICAL INSTRUMENT FOR MINIMALLY INVASIVE REMOVAL OF BIOLOGICAL MATERIAL FROM A HUMAN OR ANIMAL BODY

Description

[0001] The invention relates to a medical instrument for the minimally invasive removal of biological material from a human or animal body according to claim 1.

[0002] A variety of different medical instruments for endoscopic procedures, particularly biopsy needles and biopsy probes, are known. These can be used to remove biological material, such as tumors or parts of tissue or organs, from the human or animal body. Tumor removal can be accomplished by either punching a tumor and removing only a portion for subsequent pathological examination, or by completely removing a tumor using a vacuum biopsy. However, since the tumor is cut up and suctioned out in small fractions during vacuum biopsy, it is not possible to precisely pathologically examine the tumor's resection margins using this biopsy technique. Therefore, this procedure cannot provide any insight into the tumor's original shape, orientation, and structure within the body.In contrast to the two previously mentioned procedures, it is currently only possible to remove a tumor completely and in its original form from a patient's body using an open biopsy supported by an imaging procedure.

[0003] EP 0 761 170 A1 discloses a device for removing tissue from a human body. The described device has an elongated base body with an opening at the distal end and a cavity for receiving excised tissue. Furthermore, a cutting element is provided, which can be moved transversely to the elongated base body in the immediate vicinity of the opening during the procedure, so that removed tissue pieces are conveyed into the cavity. After removal of the corresponding material, the tissue-filled receiving space can be closed with a blunt closure.

[0004] Furthermore, US Pat. No. 5,353,804 A describes a device for removing breast tumors. The device essentially comprises a cutting element that is movable longitudinally within a cannula and has a cutting edge at its distal end. Furthermore, a wire is arranged coaxially within the cutting element, which is guided into the tissue area on the side opposite the cutting element and secured there with an anchor element. The anchor element's fixation is intended to enable a safe, as precise as possible, biopsy of the tumor.

[0005] DE 38 16 477 A1 describes a device for removing biological material from a human body, comprising a shaft with a loop-shaped removal device at one end. This removal device has a non-cutting scraping edge, which allows the removal of material during a biopsy without a cutting process. The material scraped from the patient's body is guided into the interior of the removal device and can thus be removed from the body.

[0006] US 5 573 008 A is considered to be the closest prior art and discloses an instrument according to the preamble of claim 1.

[0007] It is generally a great advantage that, thanks to ever-improving diagnostic capabilities, primarily due to high-quality imaging techniques, even relatively small tumors, especially breast tumors, are now being detected in many cases. The problem with existing technical solutions in this context is that the removal of such small tumors cannot be performed satisfactorily with the existing devices. In particular, the removal of the entire tumor and thus the most precise possible preparation of the resection margins cannot be achieved with the existing devices.

[0008] Based on the devices known from the prior art and the problems described above, it is therefore desirable to specify a device for removing biological material from a human or animal body, by means of which even comparatively small tumors, for example mammary tumors, which often have an average diameter of up to 2 cm, can be removed completely, as precisely as possible and with a clear demarcation from the surrounding, healthy tissue. It should therefore be possible to remove the biological material intended for removal from a patient's body completely, i.e. in one piece if possible, while at the same time minimizing the stress on the surrounding healthy tissue and thus on the patient. In particular, the device to be specified should be able to perform tumor or tissue removal in such a way that the resection margins can be precisely processed in pathology.The specified device should enable handling familiar to the user from other state-of-the-art instruments and have a comparatively simple design, preferably using proven construction principles. Furthermore, the specified device for the removal of biological material should also enable bipolar application using commercially available generators. Support for tumor removal through imaging techniques, particularly suitable ultrasound techniques and / or magnetic resonance imaging (MRI), should also be possible.

[0009] The above-mentioned object is achieved with a medical instrument according to claim 1. Advantageous embodiments of the invention are the subject of the dependent claims and are explained in more detail in the following description with partial reference to the figures.

[0010] The invention relates to a medical instrument for the minimally invasive removal of biological material from a human or animal body. The instrument comprises a hollow needle having a peripheral edge at a distal end defining an interior of the hollow needle, which edge has a cutting edge at least in sections, and a cutting wire arranged such that the cutting wire is movable relative to the hollow needle at least partially outside the interior.According to the invention, the medical instrument has been further developed in such a way that a guide element is provided in the interior of the hollow needle, which can be displaced in the longitudinal direction of the hollow needle and to which the cutting wire is fastened at least at one point. And that a movement means for moving the cutting wire is provided, by means of which a length of a part of the cutting wire located outside the interior can be specifically changed depending on the actuation of an actuating element. It is therefore essential to the invention that the medical instrument has a cutting wire that can be inserted into the biological material to be removed and / or the tissue surrounding this material, for example a tumor, and that the length of the part of the cutting wire located outside the hollow needle can be changed, in particular adapted as needed.With the aid of the technical solution according to the invention, it is therefore possible to change the cutting area at least partially surrounded by the cutting wire, in which a biological material intended for removal, in particular an organ or tissue part, is located, even during the procedure and to adapt it to the respective situation. It is thus possible, especially with the additional use of suitable imaging techniques such as ultrasound imaging or magnetic resonance imaging (MRI), to remove precisely the biological material intended for removal from a body in a particularly targeted manner and with minimal damage to healthy tissue. The cutting wire is arranged both in the interior of the hollow needle and attached to the movable guide element.In an advantageous manner, it is thus possible to move the guide element outwards in the longitudinal direction of the hollow needle over the distal end of the hollow needle, wherein the cutting wire is moved in the same direction.

[0011] According to the invention, the cutting wire is also movable relative to the guide element, and in the region of the part of the guide element protruding from the hollow needle, the cutting wire can form a loop or half-loop that at least partially surrounds the cutting area. By moving the cutting wire relative to the guide element, according to this embodiment of the invention, the size of the loop and thus of the cutting area can be adapted to the size of the biological material intended for removal.

[0012] In principle, it is conceivable to design the medical instrument according to the invention in such a way that it can be used either once or multiple times. A medical instrument according to the invention advantageously allows biological material, in particular tumors, with an average diameter of up to 2 cm to be removed from a human or animal body. A major advantage here is that even breast carcinomas, for example, can be removed and / or pathologically examined at a comparatively early stage. This is important because, thanks to ever-improving imaging techniques, even very small tumors can be detected and subsequently removed.

[0013] Preferably, the removal of biological material using the medical instrument according to the invention is carried out with the aid of an imaging method, for example, an ultrasound imaging method or magnetic resonance imaging, under simultaneous local anesthesia. The use of suitable imaging methods ensures safe navigation of the instrument according to the invention within the patient's body as well as precise resection of the biological material intended for removal, at least largely protecting the surrounding tissue. The medical instrument designed according to the invention can be used particularly advantageously for the removal of breast tumors.

[0014] According to the invention, the movement means for the targeted movement of the cutting wire is designed such that the cutting wire can be formed outside the interior of the hollow needle into a cutting loop or cutting snare that at least partially encloses a cutting area, wherein the size of the cutting area can be specifically changed depending on the actuation of an actuating element and the resulting activation of an adjusting element that establishes an operative connection between the actuating element and the movement means. The user, i.e., a physician performing a minimally invasive procedure with the medical instrument according to the invention, is able to specifically change the cutting area by actuating the actuating element, in particular while the hollow needle is already inside the patient's body.In this context, it is conceivable that the hollow needle, with the guide element arranged in the interior of the hollow needle and the attached cutting wire, is first inserted into the patient. Only in the area of ​​the biological material to be removed is the guide element with the cutting wire pushed out of the interior of the hollow needle beyond the distal end. The cutting wire is then moved in such a way that a cutting loop or cutting snare is formed in the area of ​​the biological material to be removed. With such an adjustable cutting snare, the resection size can be precisely adjusted and, if necessary, even changed during the procedure.

[0015] Furthermore, it is advantageously conceivable that as the medical instrument approaches the area of ​​the biological material to be removed outside the interior of the hollow needle, the loop is at least partially formed by extending the cutting wire, so that a retraction path, an opening, or a gap is created through which the biological material to be removed can later be removed from the body. In this context, it is advantageous if the guide element with the cutting wire attached to it for removing the biological material, in particular a tumor, is pierced with its distal tip centrally into the biological material to be removed, guided through it, and brought to a stop approximately 3 mm behind the biological material to be removed.The cutting wire is then preferably extended, preferably forming a cutting loop, which is adjusted to the required resection size as needed. A rotating movement of 360° or 180° in opposite directions then excises an at least approximately spherical piece of the biological material to be removed.

[0016] According to a special embodiment, it is conceivable to move the cutting wire in a suitable manner even during the cutting process, so that the shape and / or size of the cutting area and thus of the excised biological material is changed. For example, it is conceivable that a piece with at least a partially oval shape is cut out, rather than a spherical one.

[0017] A particularly advantageous minimally invasive procedure using the instrument according to the invention provides that after the cutting process has been completed, the cutting wire is retracted slightly into the interior of the hollow needle so that the cutting loop located outside the interior of the hollow needle is shortened or reduced in size, thus reducing the cutting area. The size of the cutting area is preferably halved in this case. Furthermore, while the hollow needle is being withdrawn from the patient's body, it is advantageous if the cutting wire is not retracted completely into the interior of the hollow needle, but rather remains preferably in the form of a loop in the excised biological material in order to stabilize the excised material during movement through the patient's body and thus enable comparatively easy removal.

[0018] According to a further particular embodiment of the invention, the guide element with the cutting wire attached thereto is mounted in the interior of the hollow needle in a sleeve that is arranged coaxially to the hollow needle wall, and is displaceable longitudinally within the sleeve. Furthermore, it is advantageous if the guide element has a recess that accommodates at least part of the cutting wire. It is conceivable, for example, for the guide element to be cylindrical or tubular and to have a notch on its outer side in which at least part of the cutting wire is arranged. If the cutting wire attached to the guide element at least at one point is moved relative to the guide element, at least a section of the cutting wire executes a movement within the recess in the longitudinal direction of the guide element.

[0019] In a further specific embodiment, at least one dilator element is arranged on an outer side of a hollow needle wall circumferentially surrounding the interior of the hollow needle, which dilator element is movable, at least in some areas, relative to the hollow needle wall from a rest position into an engaged position. Preferably, a surface of the dilator element in the rest position is arranged at least approximately parallel to the surface bounding the outer side of the hollow needle wall. Furthermore, it is advantageous if the dilator element in the rest position is arranged at least in some areas coaxially to the hollow needle wall and has at least two dilator arms movable in different directions into the engaged position.With the help of such a dilator element, a gap or opening can be created in the body, particularly before or while the hollow needle is moved out of its insertion position, allowing the hollow needle, with the biological material attached to it, to be relatively easily moved out of the patient's body through the surrounding healthy tissue. In a very special development, the dilator element has four dilator arms or wings that can be moved outward, at least in certain areas.

[0020] During retraction of the hollow needles with the dilator element extended into the intervention position, the tissue surrounding the hollow needle is thus slightly pushed away, creating an enlarged passage for the moved biological material. The dilator element preferably has a plurality of arms; it is particularly advantageous if these dilator arms are part of a dilator sleeve that, in the resting position, is aligned coaxially with the hollow needle wall and can be specifically activated by the surgeon if necessary. The dilator element thus ensures that a return path is dilated in the patient's body in order to achieve the most gentle movement of the excised biological material through the surrounding healthy tissue.

[0021] Furthermore, it is conceivable that the through-opening provided for the removal of the biological material is widened, for example by a wire loop, in particular the cutting wire arranged on the hollow needle according to the invention, or by a so-called knife incision.

[0022] A very specific embodiment of the invention provides that the dilator element comprises at least one shape memory material. In this context, a shape memory material is understood to be a material that returns to its original shape after deformation from a resting shape into a modified shape, for example, through the application of heat, and subsequent cooling to its original temperature.

[0023] Furthermore, special shapes of the dilator element are conceivable, particularly of the arms of the dilator element that move outward during dilation. Thus, the dilator element, particularly its arms, are preferably curved inward at the distal end, i.e., toward the hollow needle and / or the guide element, and most preferably bent. This facilitates the approach of the medical instrument to the biological material to be removed. It is also conceivable to dilate the dilator element shaped in this way and / or its arms at least slightly upon movement of the cutting wire, thus achieving a slight, blunt dilation.

[0024] According to a further specific embodiment of the invention, the dilator element is designed such that the excised biological material is grasped and secured during movement through the surrounding tissue. In this context, it is advantageous if the dilator element has a plurality of arms that are bent at their distal ends and have a gripping area on the side facing the guide element. A dilator element shaped in this way can secure the excised material with a gripping jaw like a gripping forceps.

[0025] Furthermore, in an advantageous embodiment of the instrument according to the invention, a gripping element that can be moved beyond the distal end out of the interior space is provided for securing the excised biological material. With the help of such a gripping element, the excised biological material is secured in place in order to remove it from the body as completely as possible and in its original orientation. In this case, it is conceivable for a corresponding gripping element to be designed in such a way that, after the cutting process has been completed, it can be extended in a targeted manner from the interior space of the hollow needle beyond the distal end of the hollow needle by actuating an operating element. Subsequently, suitable gripping arms of the gripping element are preferably placed around the excised biological material in order to secure it, but without damaging it.

[0026] Alternatively or additionally, it is conceivable that a corresponding gripping element for fixing the excised biological material is not arranged at the distal end of the hollow needle, but at least temporarily at the distal end of the medical instrument, which in the engagement position is located on the side of the excised biological material opposite the hollow needle.

[0027] According to a specific development of the invention, the gripping element is designed to be at least partially movable relative to the guide element and is connected to the medical instrument via suitable movement means. Preferably, the gripping element is partially arranged in the interior of the hollow needle between the hollow needle wall and the guide element, wherein it is fundamentally conceivable for the gripping element to be circumferentially surrounded by a sleeve concentric with the hollow needle wall. After the excised biological material has been grasped by the gripping element, two different scenarios for the further procedure are generally conceivable. On the one hand, it is possible for the biological material to be removed from the body by the surrounding healthy tissue in this position in which it is fixed by the gripping element.Alternatively, it is conceivable that the excised biological material is transferred with the aid of the gripping element into a removal chamber provided inside the hollow needle, where it is then removed from the body together with the other elements of the medical instrument. In this case, the guide element with the attached cutting wire is also designed in such a way that there is sufficient space inside the hollow needle to provide a removal chamber for the excised biological material.

[0028] In a further embodiment, the gripping element is at least partially arranged inside the guide element. In this context, it is conceivable for the guide element to have a cylindrical recess in its interior, in which the gripping element is arranged, wherein the gripping element is particularly preferably movable along the longitudinal axis of the guide element. Regardless of the arrangement of the gripping element, either at the distal end of the interior of the hollow needle or on the guide element, it is further advantageous if the gripping element comprises at least one shape memory material. In this case, too, the shape memory material is characterized in that it returns to its rest shape after deformation from a rest shape into a modified shape, for example by the application of heat, and subsequent cooling to the initial temperature.

[0029] A further embodiment of the invention provides that an operating situation of the medical instrument can be created in which the cutting wire is supplied with electrical energy and forms an electrode pair with the guide element, the gripping element, an electrically conductive element arranged inside the hollow needle, a sleeve arranged inside the hollow needle, or the hollow needle wall, wherein a current flow is initiated between the electrodes so that an arc forms in this area. In such an operating situation, the cutting wire advantageously forms the active electrode of the electrode pair, wherein a current flow is effected between the electrodes in order to generate an arc and thus at least assist the cutting process in the biological material.This operating situation represents a so-called bipolar application, in which a current flows between the two electrodes of the medical instrument and thus only in a defined area of ​​the biological material. Unlike the monopolar technique, the current does not flow over a large area of ​​the patient's body, and a neutral electrode is not required.

[0030] In a particularly advantageous manner, the hollow needle wall or a sleeve arranged in the interior of the hollow needle forms the counter electrode to the cutting wire representing the active electrode.

[0031] In a very special embodiment of the invention, the medical instrument is provided with a channel in which an endoscopic instrument which enables the viewing of a tissue region located in the distal direction in front of the medical instrument can be inserted. The channel is preferably designed such that an endoscope can be moved longitudinally through it during an intervention, in particular can be pulled both into and out of the patient's body. The channel is preferably arranged inside the hollow needle, very particularly inside the guide element, and has a distal opening through which an optical unit and / or camera of the endoscope can be moved at least partially into a tissue region located outside the medical instrument.Alternatively or additionally, it is conceivable that at least one endoscope, with which the surgeon can visualize the surgical area, is an integral component of the medical instrument. Preferably, an endoscope designed in this way, in particular its optical unit or camera, is attached at least partially to the hollow needle or to the guide element movable in the longitudinal direction of the hollow needle.

[0032] Furthermore, it is particularly advantageous if a medical instrument designed according to the invention is made of non-magnetic materials. This is especially necessary if the medical instrument according to the invention is used with the aid of magnetic resonance imaging (MRI) as an imaging method for removing biological material from a human or animal body.

[0033] In the following, the invention is explained in more detail, without limiting the general inventive concept, using exemplary embodiments with reference to the figures. In the figures: Fig. 1: Side view of a medical instrument designed according to the invention for removing biological material from a human or animal body; Fig. 2: Top view of the distal end of a hollow needle of a medical instrument designed according to the invention; and Fig. 3: Detail of a schematic sectional view of the hollow needle of a medical instrument designed according to the invention.

[0034] Fig. 1 shows a side view of a medical instrument 1 for removing biological material, in particular a tumor, such as breast cancer, from a human or animal body. The instrument 1 has a handle 18 by which a surgeon, in particular a doctor performing the procedure, can grasp the instrument 1, move it in a suitable manner, and initiate various operating functions by actuating at least one actuating element 11. In the area of ​​the handle 12, actuating elements are thus provided for operation, by means of which the surgeon can actuate various elements and movement means 8 of the medical instrument 1 and, in particular, move a cutting tool, which here is designed as a cutting wire 6 attached to a likewise movable guide element 7, a gripping element 17 for securing the excised biological material, and a dilator element 15.

[0035] According to the Fig. 1 In the embodiment shown, the medical instrument 1 has a hollow cylindrical or sleeve-shaped hollow needle 2, in the interior 3 of which a guide element 7 is provided which is arranged to be movable in the longitudinal direction of the hollow needle 2. In the embodiment shown in Fig. 1 In the operating state shown, the guide element 7 is in a position in which the guide element 7 projects beyond the distal end 4 of the interior 3 of the hollow needle 3. Furthermore, a cutting wire 6 is fastened to the distal end 4 of the guide element 7 and is movable due to the manual actuation of an actuating element 11 and the movement means 8 activated thereby. Furthermore, the cutting wire 6 is arranged in a recess 13 designed as a notch, which extends in the guide element 7 in its longitudinal direction and is movable relative to the guide element 7, so that a cutting loop 10, which at least partially surrounds a cutting region 9, can be formed outside the interior 3 of the hollow needle 2.For this purpose, suitable holding and / or deflection means are provided on the guide element 7, which act on the cutting wire 6 in such a way that, upon movement of the cutting wire 6 along the guide element 7 in the direction of the distal end 20 of the guide element 7, not only is the length of the cutting wire 6 located outside the interior space 3 extended, but a suitable cutting loop 10 is also formed. This process is carried out in a controlled manner by the surgeon by actuating at least one actuating element 11 in the region of the gripping element 17.

[0036] According to the Fig. 1 In the embodiment shown, a cutting loop 10 can be created outside the interior 3 of the hollow needle 2 by moving the cutting wire 6, which is used as a cutting element. The size of this cutting loop 10 and thus of the cutting area 9 at least partially enclosed by this loop 10 can be adjusted by the surgeon as needed.

[0037] Preferably, the removal of biological material, in particular a tumor with an average diameter of up to 2 cm from the female breast, is carried out with the aid of an imaging procedure, for example an ultrasound imaging procedure, a mammogram or a magnetic resonance imaging (MRI) or future imaging procedures, such as tomosynthesis or rotational computed tomography, so that the surgeon can reach the tumor safely and precisely and excise it from the healthy tissue with high precision. Fig. 1 The medical instrument 1 shown has a dilator element 15 on the outside of the hollow needle wall 14 in the form of a sleeve with four dilator arms 16, the distal ends of which can each be folded out. As soon as the hollow needle 2 with the excised biological material is to be removed from a human or animal body, the surgeon can in turn actuate the dilator arms 16 via an adjusting or operating element, so that their distal ends each move outwards and create a wedge shape, so that the excised biological material can be moved through a comparatively large through-opening through the surrounding healthy tissue and finally removed from the body.

[0038] Furthermore, a gripping element 17 with four gripping arms is arranged at the distal end 4 of the hollow needle 2. After the biological material to be removed has been cut out, these gripping arms are placed around the cut-out material, thus ensuring that the biological material can be removed from the body as completely as possible and in the original position it occupied in the body. Furthermore, according to the Fig. 1 In the embodiment shown, an anchor element 21 is provided at the distal end 20 of the guide element 7, which is mounted in a rest position inside the guide element 7 and is then extended from the guide element 7 when the hollow needle 2 and the guide element 7 are in the engaged position in the body, as will be explained in more detail below. The anchor element 21 fixes the hollow needle 2 with the guide element 7 in the engaged position during the cutting process.

[0039] In order to remove biological material from a human or animal body, in particular a tumor, for example a breast carcinoma, the hollow needle 2 with the guide element 7 located in the resting position in the interior 3 of the hollow needle 2 and the cutting wire 6 attached to it on one side is inserted into the breast with the aid of an imaging method, for example an imaging ultrasound diagnostic method. In the immediate vicinity of the tumor to be removed, the guide element 7 with the cutting wire 6 attached to it is extended from the interior of the hollow needle 2. It is also conceivable to extend the guide element 7 and the cutting wire 6 as soon as the tumor is approached and thus to create an enlarged through-opening orto create a gap through which the hollow needle 2 with the excised biological material can later be removed from the body.

[0040] Finally, the guide element 7 with the cutting wire 6 is inserted into the center of the tumor, pushed through it, and the movement is stopped as soon as the distal end 20 of the guide element 7, i.e. the tip of the medical instrument 1, is located approximately 3 mm behind the tumor. The cutting wire 6 is now moved in such a way that a cutting loop 10 of the exact required size is formed, i.e. the required radius is set. The average diameter of the excised biological material is usually about 1 cm larger than that of the tumor to be removed. In this way, the resection size can be precisely adjusted by moving the cutting wire 6 and correspondingly forming a cutting loop 10. By rotating the cutting wire 6 either by 360° or by 180° in the opposite direction, the biological material is finally excised in the shape of a sphere.It is even possible for the surgeon, if necessary, to move the cutting wire 6 in the longitudinal direction of the guide element 7 during the cutting process, thus changing the portion of the cutting wire 6 located outside the interior 3 of the hollow needle 3 and thus the size of the cutting loop 10. In this case, the cut-out material takes on a shape other than spherical.

[0041] After the biological material to be removed, in this case a tumor in the female breast, has been excised, the cutting wire 6 is retracted into the interior 3 of the hollow needle 2 in such a way that the size of the cutting area 9 and thus of the cutting loop 10 is approximately halved. This comparatively small cutting loop 10 remains in the tumor to be removed in order to stabilize it on its longitudinal axis and ensure safe and easy removal. Before the tumor is moved through the body, a gripping element 17, in particular its four-armed gripping claw, which is also arranged in the interior 3 of the hollow needle 2, is first extended and the excised tumor is fixed using the gripping claws. The excised tumor is then carefully moved out of the body.To facilitate this procedure, particularly to provide the largest possible passage for the tumor to be removed, the dilator element 15, in the form of a four-armed dilating sleeve, is actuated before retraction, so that the individual dilator arms 16 are moved outward. This creates a wedge, which further facilitates tumor removal. To achieve the most gentle tumor removal through the surrounding healthy tissue, it is conceivable that the passage opening is either enlarged using a cutting loop 10 when approaching the tumor.Preferably, a cutting loop 10 provided and used according to the invention can be supplied with electrical energy and, together with another electrode, such as the hollow needle wall 14 or another element in the interior 3 of the hollow needle 2, forms a pair of electrodes between which an electric arc is formed to assist the cutting process. Furthermore, it is conceivable to enlarge the opening for removing the biological material using a knife incision.

[0042] Fig. 2 shows a plan view of the distal end 4 of a hollow needle 2 of a medical instrument 1 designed according to the invention. It can be clearly seen that the individual components, such as the cutting wire 6, the hollow needle wall 14, a guide sleeve 12 for receiving the guide element 7 as well as the guide element 7 with the cutting wire 6 and the internally arranged anchor element 21 are arranged concentrically around a longitudinal center axis of the hollow needle 2. According to the Fig. 2 In the embodiment shown, the hollow needle wall 14 circumferentially encloses an interior space 3, in which a further sleeve, the so-called guide sleeve 12, extends longitudinally. Within this guide sleeve 12, the guide element 7 is arranged so as to be movable in the longitudinal direction. Furthermore, the guide element 7 has a longitudinally extending recess 13 in the form of a notch, in which the cutting wire 6 used as the cutting element is arranged. Furthermore, the guide element 7 has a cylindrical bore 19, also extending longitudinally, in which an anchor element 21 is arranged.

[0043] On the outer side of the hollow cylinder wall 14 is a dilator element 15, which has four dilator arms 16a, 16b, 16c, 16d arranged parallel to the outer surface of the hollow cylinder wall and shaped parallel thereto. These dilator arms are movable and can be removed, i.e., dilated, at least partially from the hollow needle wall 14 when the hollow needle 2 is withdrawn from the patient's body. In this way, a wedge can be created as needed which, when the hollow needle 2 is moved in the proximal direction, pushes away the surrounding, usually healthy tissue, thus enlarging the opening for the passage of the hollow needle 2 with the excised tumor.

[0044] Fig. 3The following shows a schematic sectional view of the hollow needle 2 of a medical instrument 1 designed according to the invention, along with the other components provided in this area. The guide element 7, which is arranged in a guide sleeve 12, is located in the interior 3 of the hollow needle 2. The guide element 7 has a longitudinally extending recess 13 in the form of a notch for receiving the cutting wire 6, which forms the cutting element.

[0045] Both the cutting wire 6 and the guide sleeve 12, within which the guide element 7 is arranged, are electrically connected to a power supply and, in a special operating situation, a so-called bipolar application, form an electrode pair, of which the cutting wire 6 is the active electrode. Upon application of a current of suitable intensity, a current flow is initiated between these two electrodes, and an arc is formed, which can at least assist the cutting process. Compared to the known monopolar applications of HF surgery, the bipolar application has the primary advantage that the current flow is limited locally within the patient's body and no neutral electrode is required.

[0046] Furthermore, a gripping element 17 is provided with a plurality of gripping arms extending in the longitudinal direction of the hollow needle 2, which circumferentially surround the guide sleeve 12 and are arranged between the guide sleeve 12 and the hollow needle wall 14. At the distal end of this gripping element 17 with multiple gripping arms are gripping claws that serve to secure the excised biological material.

[0047] On the outside of the hollow needle wall 14 and coaxial therewith there is a dilator element 15 which has individual dilator arms 16 which move outwards in sections when the excised biological material is removed from the body and thus create a through opening through which the excised biological material can be removed comparatively easily and in one piece. List of reference symbols

[0048] 1Medical instrument 2Hollow needle 3Hollow needle interior 4Distal end of the hollow needle 5Circumferential edge 6Cutting wire 7Guide element 8Moving means 9Cutting area 10Cutting loop 11Adjusting element 12Guide sleeve 13Recess 14Hollow needle wall 15Dilator element 16Dilator arms 17Gripping element 18Handle 19Hole in the guiding element 20Distal end of the guiding element 21Anchor element

Claims

1. A medical instrument (1) for the minimally invasive removal of biological material from a human or animal body with a hollow needle (2), which, at a distal end (4) delimiting an interior (3) of the hollow needle (2), includes a peripheral edge (5) having a cutting edge at least in sections, and with a cutting wire (6), which is arranged such that the cutting wire (6) can be moved relative to the hollow needle (2) at least partially outside the interior (3), wherein in the interior (3) of the hollow needle (2), a guide element (7), slidable in the longitudinal direction of the hollow needle (2), is provided, at which the cutting wire (6) is fastened at least at one point, and characterized in that a means of movement (8) for moving the cutting wire (6) relative to the guide element (7) is provided, through which a length of a part of the cutting wire (6) located outside the interior (3) can be changed in a targeted manner as a function of the actuation of a control element (11) acting on the means of movement (8), such that in the area of the part of the guide element (7) protruding from the hollow needle (2) a loop or half-loop can be created by the cutting wire (6), which at least partially surrounds a cutting area.

2. The medical instrument (1) according to claim 1, characterized in that the means of movement (8) is designed such that the cutting wire (6) outside the interior (3) of the hollow needle (2) can be shaped into a cutting loop (10) at least partially enclosing a cutting area (9), wherein a size of the cutting area (9) can be changed in a targeted manner as a function of the actuation of the control element (11).

3. The medical instrument (1) according to claims 1 or 2, characterized in that the guide element (7) with the cutting wire (6) fastened thereon is arranged in a guide sleeve (12) in the interior (3) of the hollow needle (2).

4. The medical instrument (1) according to claim 3, characterized in that the guide element (7) has a recess (13), at least in sections, in which at least part of the cutting wire (6) is arranged.

5. The medical instrument (1) according to any one of the preceding claims, characterized in that, on an outer side of a wall of the hollow needle (14) circumferentially enclosing the interior of the hollow needle (2), at least one dilator element (15) is arranged, which, at least in areas, can be moved relative to the wall of the hollow needle (14) from a rest position into an engagement position.

6. The medical instrument (1) according to claim 5, characterized in that a surface of the dilator element (15) in the rest position is arranged at least approximately parallel to a surface delimiting the outer side of the wall of the hollow needle (14).

7. The medical instrument (1) according to claims 5 or 6, characterized in that the dilator element (15) in its rest position is arranged sleeve-shaped and coaxially to the wall of the hollow needle (14) and has at least two dilator arms (16a, 16b) movable in different directions into the engagement position.

8. The medical instrument (1) according to any one of claims 5 to 7, characterized in that the dilator element (15) comprises at least one shape-memory material.

9. The medical instrument (1) according to any one of the preceding claims, characterized in that a gripping element (17), which can be moved out of the interior (3) beyond the distal end (4), is provided for fixation of the biological material.

10. The medical instrument (1) according to claim 9, characterized in that the gripping element (17) is arranged in a movable manner relative to the guide element (7).

11. The medical instrument (1) according to claims 9 or 10, characterized in that the gripping element (17) is arranged at least partially in the interior of the guide element (7).

12. The medical instrument (1) according to claims 9 or 10, characterized in that the gripping element is partially arranged in the interior of the hollow needle, between the wall of the hollow needle and the guide element.

13. The medical instrument (1) according to any one of claims 9 to 12, characterized in that the gripping element (17) comprises at least one shape-memory material.

14. The medical instrument (1) according to any one of the preceding claims, characterized in that an operating situation can be created, in which the cutting wire (6) is supplied with electrical energy and forms a pair of electrodes with the guide element (7), the gripping element (17), an electrically conductive element arranged in the interior of the hollow needle (2), a sleeve arranged in the interior (3) of the hollow needle (2) or the wall of the hollow needle (14).

15. The medical instrument (1) according to any one of the preceding claims, exclusively manufactured from non-magnetic materials.