DEVICES FOR ENUCLEATION OF INTRACORPORAL TISSUE AREAS

Description

Technical area

[0001] The invention relates to a device for enucleating intracorporeal tissue areas, in particular the prostate, comprising a probe, to the distal end of which at least one freely accessible electrode body is attached, which can be supplied with electrical energy via at least one electrical line running in the longitudinal extension of the probe. State of the art

[0002] Devices for the enucleation of intracorporeal tissue areas are primarily used for the treatment of benign prostatic hyperplasia (BPH). Widely used for this purpose are endoscopic instruments that are minimally invasively inserted transurethally (i.e., through the urethra) intracorporeally into the location of the prostate to be treated, in order to completely or partially remove benign enlarged prostate areas.So-called resectoscopes are used to perform this minimally invasive surgical procedure, also known as transurethral prostate resection (TURP), see, for example, the document DE 935391 B. These resectoscopes have at least one working channel for the purpose of local tissue ablation. A probe-like electrode catheter can be guided through this channel. This catheter has a loop-shaped distal electrode tip that can be subjected to high-frequency alternating current, which heats the electrode loop, allowing local thermally induced tissue layer separation. To ensure good visual control during tissue ablation, irrigation fluid is continuously introduced and aspirated through the resectoscope during the operation.The irrigation fluid used in so-called monopolar resections is electrolyte-free, whereas isotonic saline solutions are used in bipolar resectoscopes. RF monopolar or bipolar resection of the prostate is considered the gold standard in the treatment of BPH, but it also has some disadvantages. For example, with this treatment method, the resection of the benign glandular tissue developing in the prostate is usually incomplete, and the procedure times required for tissue sampling are long, especially in the case of larger adenomas, resulting in considerable stress for the patient.Furthermore, the rinsing of the tissue area treated by TURP with hypotonic rinsing solution, which is required during monopolar resectoscopy, can sometimes lead to a so-called TUR syndrome, which causes infiltration into the vascular system and can result in possible complications such as pulmonary edema, cerebral edema, hemolysis and renal failure.

[0003] Newer transurethral endoscopic enucleation techniques using laser-based resectoscopes, particularly holmium laser enucleation of the prostate (HoLEP), demonstrate improved clinical results. Laser-based prostate enucleation allows for the treatment of even very large adenomas and, in particular, enables layer-specific dissection, allowing for gentle detachment of the layers between the prostate capsule and the enlarged prostate gland or adenoma. This procedure allows for a particularly bloodless operation compared to conventional techniques based on the use of the RF electrode loops described above. In contrast to conventional techniques, laser-based enucleation offers complete, histological separation and processing of the tissue to be removed.

[0004] Due to the high costs and the large volume of equipment that needs to be placed in the operating room, the availability and accommodation of such systems is only possible in a few locations.

[0005] US Pat. No. 10,470,837 B2 describes a device and a method for treating rhinitis, i.e., chronic inflammation of the nasal mucosa, with which it is possible to ablate nerve branches of nasal nerves located in the posterior nasal cavity. A flexible surgical probe allows its introduction and positioning into the submucosal space of a lateral nasal wall, where neuroablation of the posterior nasal nerve can be performed with the surgical probe. The probe device has a light source at its distal probe tip that illuminates the submucosal tissue to allow the surgeon to visualize the submucosal position of the distal end of the surgical probe from inside the nasal cavity. In one embodiment, the probe tip is rounded and has an RF electrode arrangement for the local generation of Joule heating.

[0006] German patent document DE 696 36 885 T2 discloses a surgical system with a cooled electrode tip. A cooling system is integrated along the hollow electrode body, whose distal end can be pointed or rounded. This cooling system allows the amount of heat applied to the intracorporeal environment via the electrode arrangement at the distal region to be controlled in order to prevent overheating.

[0007] The document DE 10 2015 119 694 A1 describes an electrosurgical system for the resection of body tissue, which comprises at least two electrodes which are subjected to high-voltage electrical pulses by means of a high-voltage supply unit for the purpose of short-lived gas bubble formation within a liquid in contact with the electrosurgical system.

[0008] The electrode stimulation probe described in the document DE 88 07 820 U1 has a shape and size adapted to the anatomical conditions of the human sphincter area for the treatment of bladder or anal incontinence as well as hemorrhoids.

[0009] WO 02 / 098312 A2 discloses a probe assembly with a distal probe tip, similar to a puncture needle tip, for electrothermal coagulation of tissue. It provides two electrodes, one connected to an inner conductor and the other to an outer conductor. The inner and outer conductors of the probe assembly are electrically insulated from each other. The inner conductor is further selected to increase the flexural rigidity of the probe assembly.

[0010] The document DE 10 2017 100 409 A1 describes an electrosurgical device which has a handle and a shaft attached to it in a controlled manner.

[0011] An electrosurgical instrument for treating the prostate is known from GB 2 308 979 A. Furthermore, another electrosurgical instrument is known from WO 03 / 024349 A1. Description of the invention

[0012] The invention is based on the object of developing a device for enucleating intracorporeal tissue areas, in particular the prostate, with a probe having at least one freely accessible electrode body attached to its distal end, which can be supplied with electrical energy via at least one electrical line running longitudinally along the probe. This device avoids the disadvantages previously associated with RF monopolar or bipolar resection of the prostate, and enables comparable surgical properties and results to those achievable with laser-based endoscopic enucleation of the prostate, or EEP for short. In particular, the aim is to create a cost-effective and qualitatively equivalent alternative to the complex laser-based EEP.

[0013] According to the solution, the device for enucleating intracorporeal tissue areas, in particular for treating benign prostatic hyperplasia, is characterized by the features of independent claims 1, 2 and 12.

[0014] The device according to the solution is based on the idea of ​​largely completely simulating the handling and therapeutic effect of a laser catheter designed for the purpose of transurethral prostate enucleation by means of a probe capable of electrical ablation and coagulation of tissue layers or areas, which can also be used in conjunction with a resectoscope.

[0015] The dome-shaped electrode body attached to the distal end of the probe is designed in such a way that the electrode body surface has gliding properties, i.e., it is completely smooth and without undercuts or edges. This allows distal advancement or lateral movement of the probe using the smooth, dome-shaped electrode body to achieve the most atraumatic and blunt preparation of the tissue area to be treated. The dome-shaped or dome-shaped electrode body is capable of opening or separating tissue layers or tissue layers through a purely mechanical displacement process through finely controlled distal or lateral advancement, with no or no significant lesion formation.

[0016] The probe design of this solution is based, among other things, on the realization that the gentle, laser-based tissue separation process, e.g., HoLEP, depends essentially on the beam quality and pulse of the laser beam emitted from the distal end of the laser catheter. In addition to the beam power, beam diameter, beam divergence, wavelength, and frequency, the beam intensity distribution and the beam interaction with the energy-absorbing medium along the beam cross-section play a role in the interaction between the laser beam, the potential resulting formation of gas bubbles, and the tissue areas to be penetrated or prepared for the purpose of precise, time-efficient, and gentle detachment of the adenoma from the prostate.

[0017] High-quality laser beams exhibit minimal beam divergence and a beam intensity distribution along the beam cross-section in the form of a Gaussian curve, which is why such laser beams are also referred to as Gaussian beams. This spatial beam intensity distribution and the specific pattern of spatial energy distribution at the site of energy application appear, according to current knowledge, to be the prerequisites for the advantages associated with laser-based prostate enucleation, which provides the inspiration and basis for the spatial formation of the solution-designed electrode surface of the electrode body attached to the distal end of the probe.

[0018] The dome-shaped design of the electrode body is inspired and motivated, among other things, by the spatial shape of the radiation intensity profile of a Gaussian beam and enables blunt dissection of tissue areas or layers by gently moving the probe distally or lateralward. Since the electrode body can also be supplied with electrical energy via at least one electrical lead, the tissue can be further electrically transected, ablated, and / or coagulated if necessary.

[0019] The electrode body, preferably made of metal or a metal alloy, is electrically connected either as a monopolar electrode with an electrical lead running along the probe, or as a bipolar electrode with two electrical leads running along the probe. The novel probe can be used in conventional resectoscopes and connected to standard HF devices available in the operating room. The device according to the solution enables precise, time-efficient, and gentle treatment of the prostate through the urethra and, as with laser-based resectoscopes, increases surgical safety and can significantly reduce complication rates compared to conventional electrical prostate resection techniques (TURP). Furthermore, the device according to the solution is cost-effective and has the potential to have positive health-economic effects on the entire healthcare system.

[0020] Preferably, the dome-shaped electrode surface of the electrode body is modeled, at least along the first axial section, in the form of a spatial radiation intensity distribution of a laser beam with a Gaussian intensity distribution, a paraboloid, or an ellipsoid. Likewise, other spatial shapes are also conceivable and feasible, in which the cross-sectional areas of the electrode body along the respective first axial section are each surrounded by a peripheral edge that is either exclusively curved or has curved and straight peripheral edge sections, wherein the transitions between curved and straight peripheral edge sections are smooth, i.e., continuously differentiable. The described curved design allows the surgeon to work by rotating the instrument in a preferred direction.

[0021] If, in contrast, the longitudinal sections through the electrode body oriented orthogonal to the individual cross-sectional areas are considered, a preferably designed electrode body has only longitudinal sections, each of which is delimited by a circumferential contour that is also continuously differentiable at every point, i.e., is smooth. The circumferential contours delimiting the individual longitudinal sections can preferably be described by a partial circle, a parabola, a partial ellipse, or a partial oval. The essential characteristic of all domed electrode surfaces according to the solution is their smooth, outwardly visible shape, which is suitable for severing tissue areas, in particular tissue layers, by means of a gentle mechanical displacement process determined by the shape of the electrode body, without or largely without lesions.Sharp-edged surface contours or contours with small radii, as are common with conventional electrode loops, are expressly excluded from the design of the electrode body in order to reach or mechanically penetrate between two anatomical tissue layers with the help of the electrode body as lesion-free as possible.

[0022] In a further preferred embodiment, the dome-shaped electrode body has a nipple-like, equally smooth, dome-shaped extension in the region of its distal end, which gently supports the mechanical separation process during distal advancement of the probe designed according to the invention. Further explanations of this can be found in the following illustrations.

[0023] The smooth, dome-shaped electrode body is adjoined proximally by a second axial section, along which the cross-sectional areas oriented orthogonally to the longitudinal extension of the electrode body remain constant with increasing distance from the distal end of the dome. Preferably, the cross-sectional areas along the second axial section are circular, so that the electrode body assumes a straight-cylindrical outer shape in this region.

[0024] The electrode body designed according to the invention is rigidly connected to the probe, which is preferably designed as a hollow cannula and capable of transmitting axial shear or compressive forces as well as bending forces. The rigid connection of the electrode body to the hollow cannula is preferably achieved via a biocompatible, biomolded, electrically insulating joining agent in the form of a mechanical intermediate piece, for example, made of ceramic, plastic, or glass, or a cast part, for example, based on epoxy resin, which has solidified for connection purposes.

[0025] The hollow cannula probe also possesses high flexural strength, allowing it to withstand mechanical transverse loads acting on the electrode body relative to the probe's longitudinal extension without undergoing any deformation. Such transverse loads can occur, for example, when the surgeon moves the electrode body laterally or transversely to the probe's longitudinal extension for tissue ablation or detachment. In this case, no or only minimal deformation should occur, preferably along the entire probe, but at least in the distal region of the probe that extends distally from the resectoscope for the purpose of blunt dissection. To ensure dimensional stability, it is advisable to manufacture the hollow cannula probe from a metallic material, e.g., instrumental steel, or a robust, rigid, preferably fiber-reinforced plastic with a suitably thick hollow cannula wall thickness.

[0026] Thus, at least in the distal probe region, the probe has a rigidity or flexural strength such that when a bending moment is applied to the probe, which is caused by a force acting on the electrode body transversely to the probe's longitudinal extent, while the probe is mechanically firmly clamped at a distance of at least 30 mm from the distal probe tip - which corresponds to a typical probe guide lengthwise and through a resectoscope - the distal probe tip is deflected by a maximum of 2 mm transversely to the probe's longitudinal extent and under no circumstances does plastic deformation of the probe occur. For a deflection of 2 mm, the applied force is measured and the bending moment is calculated (F x I). The probe is designed such that the above requirements for the dimensional stability of the probe are guaranteed at a bending moment of at least 0.1 Nm, preferably at least 0.2 Nm, particularly preferably at least 0.3 Nm.

[0027] Preferably, all surfaces—that is, the surface of the electrode body, the joining element, and the rigid hollow cannula proximally connected to it—are designed to be low-friction, i.e., smooth and surface-gliding. It is advisable to polish or hone at least the electrode surface of the electrode body.

[0028] The device according to the invention can be partially or completely provided with a surface treatment that increases lubricity, preferably in the form of a coating. The coating consists, for example, of PTFE, polyurethane, polysiloxane, a hydrogel, or a polymer with additives that reduce sliding resistance, or a combination thereof.

[0029] The mechanically rigid connection between the hollow cannula, joining element, and electrode body enables mechanical force transmission along the probe in the axial and lateral directions to the electrode body, enabling gentle and targeted tissue separation in the form of an atraumatic, blunt dissection. The term "blunt dissection" refers to the separation of two anatomical structures connected by a connective tissue and / or vascularized or avascularized layer. In this way, an artificial space is created that can be formed under normal biophysiological and anatomical conditions. The process of blunt dissection is performed exclusively by mechanical movement in a distal forward direction, as well as by lateral back-and-forth swinging and / or rotational movements of the electrode body around the longitudinal axis of the probe.A surgeon initiates the hollow cannula in the intracorporeal tissue target area. If necessary, the electrically conductive electrode body can exert an additional cutting, ablation, and / or coagulation effect within the tissue area through high-frequency current.

[0030] In order to push two anatomical layered structures apart in a way that is as gentle on the tissue as possible and effective for the surgeon, yet still finely dosed and directionally selective, spatial shapes have proven particularly suitable for the design of the electrode body along the first electrode section. These spatial shapes deviate from axial symmetry about the longitudinal axis of the probe and have two-dimensional cross-sectional shapes that are flattened along one of two orthogonally oriented cross-sectional axes, similar to the shape of a spatula. By flattening the otherwise round, i.e. edge-free, electrode body shape, a flat pushing apart of two anatomical layered structures is easier because the flattened electrode body surfaces, which each lie opposite one another along a cross-sectional axis, are guided parallel between the layered structures to be separated during probe advancement.

[0031] Preferably, but not necessarily, the flattened electrode body surfaces are each formed symmetrically to a cross-sectional area, for example, both electrode body surfaces have at least one flat surface area, or both electrode body surfaces have at least one convexly curved surface area. It is also conceivable for one electrode body surface to be convex and the other electrode body surface to be concavely curved, or for one of the two electrode body surfaces to have at least one curved surface area and the other electrode body surface to have at least one flat surface area.

[0032] In the case of an asymmetrical flattening of the electrode body, one of the two electrode body surfaces preferably has a curved surface shape in the longitudinal extension of the probe's longitudinal axis, along which at least one inflection point of curvature is contained. The opposite electrode body surface, in contrast, is preferably largely rectilinear. Of course, different flattened electrode body surface shapes are conceivable, enabling effective penetration between and separation of two tissue layers.

[0033] Furthermore, an asymmetric flattening of the electrode body allows the surgeon to perform tilting movements that act on the tissue surroundings by alternating bidirectional rotation of the electrode body around the longitudinal axis of the probe when advancing the probe, which can support the process of pushing apart two anatomical layer structures in certain cases.

[0034] Furthermore, an asymmetric flattening of the electrode body opens up the possibility of an asymmetrical formation of electrode contact surfaces that come into contact with the tissue. For example, the largely rectilinear, flattened electrode body surface shape explained in the above exemplary embodiment can be electrically conductive, whereas the oppositely curved electrode body surface shape is at least not completely electrically conductive and is, for example, locally covered with an electrically insulating layer, or vice versa.

[0035] The device according to the invention is particularly suitable for surgical use in conjunction with a resectoscope known per se, which, in addition to a working channel for passing the probe according to the invention, provides additional working and / or rinsing channels, thereby enabling the surgeon to perform an optically monitored transurethral prostate enucleation. For the purpose of centered and position-defined guidance of the probe along the working channel of the resectoscope, at least one guide sleeve is preferably attached along the hollow cannula. This guide sleeve serves both as a centering and sliding element and as a guide element for at least one other medical instrument parallel to the probe through the working channel. Brief description of the invention

[0036] The invention is described below, without limiting the general inventive concept, using exemplary embodiments with reference to the drawings. They show:Fig. 1a,bSide view and top view of a device designed according to the solution, Fig. 2a,bExemplary embodiment of an electrode body in longitudinal section and bottom view, Fig. 3a,bExemplary embodiment of an electrode body with distal additional dome structure, Fig. 4 - 7Alternative spatial shapes for forming the electrode body along the first axial section, Fig. 8a-eLongitudinal section a), longitudinal view b) rotated by 90° of an electrode body attached to the distal side of the probe, as well as cross sections c), d), e), Fig. 9a-eLongitudinal section a) and longitudinal view b) rotated by 90° of an alternative embodiment of an electrode body attached to the distal side of the probe, as well as cross sections c), d), e), Fig. 10a-cLongitudinal section of an electrode body attached to the distal side of the probe a), cross sections b), c), Fig. 11a,bLongitudinal section of a the electrode body attached to the probe a), cross section b) and Fig.12Longitudinal section of an electrode body attached to the distal side of the probe. Ways of implementing the invention, industrial applicability

[0037] In the Figures 1a, bA device for enucleating intracorporeal tissue areas is shown in a side and top view. The device has a probe 1 designed as a hollow cannula, to the distal end of which a freely accessible electrode body 2 is firmly attached. The electrode body 2 is connected to at least one, preferably two electrical lines 3, which are guided longitudinally proximally within the probe 1 and are designed to be connectable to an electrical energy source (not shown). Typically, a guide sleeve 4 is attached along the probe 1, which serves as a centering and sliding element within and along a working channel of a resectoscope (not shown in detail) and also enables the passage of a medical instrument, e.g., an optical conductor.The electrically conductive electrode body 2, preferably made of metal or a metallic material, has at least a first axial section 5, which has a dome-shaped electrode surface 6, which is spherical in the illustrated embodiment. The electrode body 2 has, according to . Fig. 1 a second axial section 6 which is straight-cylindrical in shape and seamlessly adjoins the first axial section 5.

[0038] The metallic electrode body 2 is firmly connected to the probe 1, which is designed as a hollow cannula, via a biocompatible, electrically insulating joining means 7. The joining means 7 is designed, for example, as a shaped body for connecting the electrode body to the hollow cannula.

[0039] The curvature of the electrode surface of the electrode body 2 in the first axial section 5 is predetermined by the design and optimally selected for the blunt preparation process. Preferred electrode surface geometries for the formation of the electrode body 2 are described below.

[0040] In Fig. 2a Illustrated is a longitudinal section through a bipolar electrode body 2, which provides two electrical contact sleeves 8 for the purpose of electrical contact, into which the ends of the electrical lines 3 each open and are firmly connected to the electrode body 2. Furthermore, the electrode body 2 is separated by an electrically insulating intermediate layer 13 into two mutually electrically insulated electrode body halves 2', 2". Figure 2b In contrast, a monopolar electrode body 2 is shown with only one electrical contact sleeve 8.

[0041] The Figures 2a, bThe electrode bodies 2 shown each have a spherically shaped dome shape along the first axial section 5, which merges seamlessly and smoothly into a straight-cylindrical outer shape along the second axial section 6.

[0042] The cross-sectional areas of the electrode bodies 2, each spherically formed along the first axial section 5, correspond to circular areas with continuously increasing circular diameters up to a circular diameter corresponding to the diameter of the straight-cylindrical outer shape along the second axial section 6. The corresponding longitudinal sections through the electrode body 2 thus represent semicircular areas in the first axial section 5.

[0043] Fig. 3a represents a form variant for the formation of the electrode body 2, which, in contrast to the spherical dome shape according to Fig. 2 a, badditionally has a smaller dome shape 10. The nipple-like dome 10 serves to support the separation of two anatomical structures that are connected to each other by a connective tissue and / or vascularized or avascularized tissue layer.

[0044] The Fig. 3b The illustrated view shows a top view of the distal end 9 of the electrode body 2 in a proximal projection. The circular configuration of the nipple-like dome shape can be seen from this view. The transition between the nipple-like dome 10 and the remaining contour of the electrode body 2 within the first axial section 5 is seamless and smooth, i.e., the surface of the electrode body 2 is continuously differentiable at every point.

[0045] The shape of the dome-shaped electrode body 2 can be different from the spherical dome-shaped design according to the embodiments of the Figures 1 and 2differ.

[0046] In the Figures 4 to 6 further alternative spatial shapes for the design of the electrode body 2, in particular along the first axial section 5, are shown. Fig. 4 shows the spatial shape of a paraboloid, Fig. 5 the reproduction of a Gaussian radiation intensity distribution which corresponds equal to or approximately and in sections to the spatial shape of an ellipsoid.

[0047] Fig. 6 gives the spatial shape of a paraboloid, comparable to the representation in Fig. 4 again, which is, however, supplemented by a nipple-like additional dome shape 10 at the distal end of the electrode body 2.

[0048] Fig. 7aillustrates in perspective view a further embodiment for the shape of the electrode body 2 at least along the first section 5. In this case, the dome-shaped design of the electrode body is shovel-like or rounded flattened. By flattening the electrode body 2 within the first section 5 along the y-axis, see the Figure 7a In the xyz coordinate system shown, two flattened electrode surfaces 14, 15 opposite each other along the y-axis are formed, which are each guided parallel or largely parallel between two tissue layers to be separated for the purpose of pushing apart the two anatomical layer structures.

[0049] In the Figures 7b and 7c are sectional views through the electrode body 2 along the cutting plane zy, see Figure 7b , and along the section plane zx, see Figure 7cshown in solid lines. The dashed profile sections in the Figures 7b and 7c represent, in a non-limiting way, variations for the formation of the spatial form of the Figure 7a illustrated electrode body 2.

[0050] In addition, the Figures 7d and 7e possible alternative cross-sectional shapes A1 to A5, in the sequence of Figure 7a specified cutting planes.

[0051] In the case of cross-sectional shapes according to Fig. 7d The electrode body 2 has cross-sectional shapes A1 to A5 in the first axial section 5, each of which has a straight section 11 and curved sections 12. With increasing distance from the distal end 9, the cross-sectional shapes A1 to A5, etc., morphologically approach a circular cross-section. The straight sections 11 are each assigned to the flattened electrode surfaces 14, 15.

[0052] In the case of Fig. 7eThe illustrated cross-sectional shapes A1 to A5 are elliptical cross-sections whose cross-sectional sizes increase continuously from the distal end 9 proximally. The slightly curved elliptical sections are assigned to the flattened electrode surfaces 14, 15.

[0053] In this case too, the elliptical cross-sectional shapes morphologically transition into a circular cross-section A6, which corresponds to the outer hollow cannula cross-section of probe 1.

[0054] In Figure 8aA longitudinal section through another embodiment for enucleating intracorporeal tissue regions is shown, comprising a probe 1 configured as a rigid hollow cannula, to whose distal end an electrode body 2 is attached, which can be supplied with electrical energy via at least one electrical line 3 running longitudinally along the probe 1. The electrode body 2 is galvanically decoupled from the metallic probe wall by an electrical insulation layer 13 incorporated within the probe 1. Furthermore, an electrically insulating ceramic sleeve body 16 encompasses the electrode body 2, which projects beyond the hollow cannula 1 on the distal side. The ceramic sleeve body 16 fits flush with the outer contour of the hollow cannula 1.The region B of the electrode body 2 projecting distally beyond the electrically insulating ceramic sleeve body 16 is flattened, similar to the shape of a spatula, and has two electrode surfaces 14, 15, the shape of which can be seen from the longitudinal section view according to . Figure 8a and the opposite Figure 8a 90° rotated side view according to Figure 8 b Possible spatial configurations of the electrode body 2 are also described below with reference to the Figures 8c to 8e can be found.

[0055] The distal end 17 of the spatula-shaped, flattened electrode body 2 has a distally rounded contour, to which the two electrode surfaces 14, 15 adjoin seamlessly. Furthermore, the distal end 17 is arranged off-center relative to the probe's longitudinal axis 18. The electrode surface 15 terminates, largely maintaining its contour, at the outer wall of the proximally extending electrode body 2. The electrode surface 14, on the other hand, is curved in a shovel shape and adjoins seamlessly radially the front edge of the ceramic sleeve body 16, which is designed to maintain its shovel shape.

[0056] In practical use, the probe's rounded end 17 ensures gentle displacement and separation of two tissue layers. The shape of the two electrode surfaces 14 and 15, as well as the proximal, frontal contours of the ceramic sleeve body 16, allow for spatial spacing of the separated tissue areas.

[0057] In Figure 8c is a preferred cross-sectional shape through the electrode body 2 along the Fig. 8b shown in section AA. Both electrode surfaces 14, 15, which are flattened along the y-cross-sectional axis, are flat and symmetrical to the x-cross-sectional axis and are connected at their surface ends opposite the y-axis by a rounded, preferably cylindrical surface shape 20, 21.

[0058] An alternative cross-sectional shape is in Figure 8dIn this case, the electrode surfaces 14, 15 are also symmetrical to the x-cross-sectional axis, but flat, converging towards each other. The surface ends of both electrode surfaces 14, 15 are each connected via differently dimensioned cylindrical surface shapes 20, 21, of which the one shown in the cross-sectional view according to Fig. 8d left surface shape 21 has a larger radius of curvature than the opposite surface shape 20. The wider or thicker, rounded surface shape 21 supports the separation process between two tissue layers during a sideways movement of the probe in the direction of the thicker surface shape 21, avoiding cuts in the tissue.

[0059] Another alternative cross-sectional shape shows Figure 8 e. In this case, the electrode surface 15 is flat and the opposite electrode surface 14 is convex.

[0060] A difference from the above in the Figures 8a, b The modified version shown in the embodiment is shown in Figure 9 a, b , which shows both a longitudinal section and a longitudinal view rotated by 90°. In this case, the region B of the electrode body 2 projecting distally beyond the ceramic sleeve body 16 adjoins radially and axially flush with the outer wall of the ceramic sleeve body 16, wherein the electrode surface 15 adjoins axially flush with the outer wall of the ceramic sleeve body 16, whereas the electrode surface 14 is curved in a shovel-like manner and has a curvature inflection point 19. The Figures 9 a, b The electrode body 2 shown can take on spatial forms that are determined by the Figures 9 c to 9e are given alternative cross sections, similar to those shown in the Figures 8c to 8e shown cross-sectional shapes.

[0061] In all of the above-illustrated embodiments, the entire surface area of ​​the electrode body 2 is smoothly polished and / or honed, at least along the area B. Preferably, the electrode surface of the electrode body 2, the ceramic sleeve body 16, and the probe 1 are coated with a low-friction coating, preferably with a coating comprising PTFE, TPU, polysiloxane, or hydrogel.

[0062] In Figure 10 a shows a longitudinal section through another embodiment of a device according to the invention. To avoid repetition, those components that are structurally identical and / or function identically to previously explained components are provided with the reference numerals already introduced and explained.

[0063] The electrode body 2, made of an electrically conductive and dimensionally stable material, preferably metal or a metal alloy, is mechanically stable, torsion-free, rigid, and electrically insulated within the hollow cannula 1 and the adjoining ceramic sleeve body 16. Region B of the electrode body 2, protruding distally from the ceramic sleeve body 16, is spoon-shaped or scoop-shaped. At its distal end 17, the electrode body 2 has a bead-shaped and rounded thickening 22. The electrode surface 15 ends flush on the proximal side with the outer contour of the ceramic sleeve body 16. Over a distance I, the electrode surface 15 runs essentially parallel and straight to the longitudinal extension of the ceramic sleeve body 16. Following this, the electrode surface 15 is convexly curved and ends at the distal end 17 in the bead-shaped and rounded thickening 22.

[0064] The electrode surface 14 is essentially spoon-like and concave and has bead-like edge contours 23 on both of its long sides, the spatial shape of which is shown in the cross-sectional view according to Fig. 10b along the section plane BB.

[0065] Due to the raised edges on both sides caused by the bead-shaped edge contours 23 compared to the concave depression on the electrode surface 14 located centrally to the probe's longitudinal axis, this shape imparts to the electrode body 2 increased dimensional and flexural rigidity, particularly when forces are applied transversely to the probe's longitudinal extension. The surface contour of the electrode surface 14 resembles the outer contour of a figure-eight, whereas the opposite electrode surface 15 is smooth.

[0066] In the distal area of ​​the bulging and rounded thickening 22 along the Figure 10aThe electrode body 2 has the section line CC shown in Figure 10 c shown oval or elliptical cross-sectional shape.

[0067] The radial extension or spatial extent of the electrode body 5 does not exceed the radial dimension of the hollow cannula 1, which is predetermined by the outer diameter b, so that it is ensured that the entire probe can be guided unhindered through a working channel, e.g. of a resectoscope, which is dimensioned to fit the hollow cannula.

[0068] In Figure 11a is a longitudinal section through a probe which, instead of the ceramic sleeve body 16 and the electrode body 2, as described above, Figure 10explained, has a body 24 projecting into the hollow cannula 1 and firmly connected to the hollow cannula 1, which, with the exception of the bead-shaped and rounded thickening 22 made of an electrically conductive material, is made of an electrical insulator, preferably a ceramic, or a fiber-reinforced polymer, for example GRP, and otherwise has the shape of the one shown in the preceding Figures 10 a, b illustrated and explained electrode body 2. An electrical conductor arrangement 3 runs through the body 24 and is connected to the electrically conductive thickening 22.

[0069] The cross-sectional view according to Figure 11 b corresponds to the cross section through the body 24 along the section plane AA according to Figure 11a and is the cross section of the electrode body 2 along the section plane BB according to Figure 10b In addition, a feedthrough channel 25 for the electrical conductor arrangement 3 is provided in the cross section.

[0070] The Figure 11a The probe illustrated allows for the application of electrical energy, limited to the area of ​​the bulged and rounded thickening 22, as needed, thus achieving a coagulation effect on the surrounding tissue. All other surface areas of the body 24 are electrically inactive.

[0071] As an alternative to the design of the electrically insulating body 24, Figure 12a longitudinal section through an embodiment in which the body 24' is made of a metallic, electrically conductive material. The body 24' is firmly joined to the hollow cannula 1 or connected thereto in one piece. An electrical insulator 25 is attached to the distal side of the metallic body 24', to which is attached, electrically insulated from the metallic body 24', the bead-shaped and rounded thickening 22 made of a metallic material is attached, which can be supplied with electrical energy as required via the electrical conductor arrangement 3. The metallic body 24', the spatial shape of which essentially corresponds to that of the previously explained body 24 according to Figures 11 a, b or electrode body 2 according to Figure 10ahas a high degree of robustness and flexural rigidity, particularly in the case of a one-piece or monolithic design with the hollow cannula 1. The metallic body 24' has a cross-section along the section line AA which corresponds to the cross-section according to Figure 11b equals. List of reference symbols

[0072] 1 Probe, hollow cannula 2 Electrode body 3 Electrical conductor 4 Guide sleeve 5 First axial section 6 Second axial section 7 Joining element 8 Contact sleeve 9 Distal end 10 Nipple-like dome shape 11 Straight section 12 Curved section 13 Electrically insulating intermediate layer 14, 15 Electrode body surface 16 Ceramic sleeve body 17 Distal end 18 Probe longitudinal axis 19 Curvature inflection point 20, 21 Surface shape 22 Thickening 23 Bead-like edge contour 24 Electrically insulating body 25 Feedthrough channel

Claims

1. Device for enucleation of intracorporeal tissue areas, in particular the prostate, with a probe (1) which is designed as a rigid hollow cannula and at whose distal end (9) at least one freely-accessible electrode body (2) is attached, which can be supplied with electrical energy via at least one electrical line extending in the longitudinal direction of the probe (3), wherein the electrode body has a dome-shaped electrode surface and cross-sectional areas (A1-A6) oriented orthogonally to the longitudinal axis (z) of the probe, the surface areas of which increase steadily along a first axial section (5) which contains the distal dome end of the electrode body, with increasing distance from the distal dome end, and wherein the cross-sectional areas are each bounded by a peripheral edge which is continuously differentiable at every point, wherein the probe has a bending strength, at least in the region of the electrode body connected to the probe on the distal side, which ensures the dimensional stability of the probe under the action of a bending moment of at least 0.1 Nm acting on the electrode body transversely to the longitudinal extension of the probe, and wherein the freely-accessible electrode body is spatula-shaped and is flattened along a cross-sectional axis of a cross-section associated with the electrode body in such a way that the electrode body has two flattened electrode body surfaces (14, 15).

2. Device for enucleation of intracorporeal tissue areas, in particular the prostate, with a probe (1), which is designed as a rigid hollow cannula and to whose distal end (9) at least one freely-accessible electrode body (2) is attached, which can be supplied with electrical energy via at least one electrical conductor (3) extending in the longitudinal direction of the probe, wherein the electrode body has a dome-shaped electrode surface and cross-sectional surfaces oriented orthogonally to the longitudinal extension of the longitudinal extension of the probe, the surface areas of which increase continuously along a first axial section, which contains the distal dome end of the electrode body, with increasing distance from the distal dome end, and wherein the cross-sectional areas are each bounded by a peripheral edge which is continuously differentiable at every point, wherein the probe has a bending strength, at least in the region of the electrode body connected to the probe on the distal side, which ensures the dimensional stability of the probe under the action of a bending moment of at least 0.1 Nm acting on the electrode body transversely to the longitudinal extension of the probe, wherein the freely-accessible electrode body is designed in a shovel shape and is flattened along a cross-sectional axis of a cross-section assigned to the electrode body in such a way that the electrode body has two flattened electrode body surfaces, one of which has a straight surface section on the proximal side, which is connected to a convexly-curved surface section on the distal side, and the other is convexly-curved and has a bead-shaped and rounded thickening (22, 23) on the distal side.

3. Device according to claim 1 or 2, wherein at least the region of the electrode body connected to the probe on the distal side extends from its distal electrode tip to a maximum of 30 mm proximally along the probe.

4. Device according to any one of claims 1 to 3, wherein the electrode body is made of metal or a metal alloy, which is electrically connected in the form of a monopolar electrode with the electrical conductor guided along the probe or in the form of a bipolar electrode with two electrical conductors guided along the probe.

5. Device according to any one of claims 1 to 4, wherein a guide sleeve is attached along the probe for guiding a medical instrument parallel to the probe and / or as a centering and sliding element within and along a working channel of a resectoscope.

6. Device according to any one of claims 1 to 5, wherein the electrode surface of the electrode body and / or the probe is coated with a low-friction coating and wherein the coating comprises TFE, TPU, polysiloxanes or hydrogel.

7. Device according to any one of claims 1, 3 to 6, wherein the two flattened electrode body surfaces have one of the following pairs of shapes: both electrode body surfaces have at least one flat surface area, both electrode body surfaces have at least one convexly-curved surface area, one electrode body surface has at least one convexly-curved surface area and the other electrode body surface has at least one concavely curved surface area, one of the two electrode body surfaces has at least one curved surface area and the other electrode body surface has at least one flat surface area.

8. Device according to any one of claims 1, 3 to 7, wherein the freely-accessible electrode body has an oval-shaped cross-section that is symmetrical with respect to a longitudinal axis associated with the oval.

9. Device according to claim 8, wherein the oval-shaped cross-section is asymmetrical with respect to an axis orthogonal to the longitudinal axis.

10. Device according to claim 2, wherein the freely-accessible electrode body does not protrude radially beyond the rigid hollow cannula in the axial projection.

11. Device according to claim 2, wherein the freely-accessible electrode body has a cross-section which, at least in some areas, has the outer shape of a figure eight.

12. Device for enucleation of intracorporeal tissue areas, in particular the prostate, with a probe (1) which is designed as a rigid hollow cannula and at whose distal end (9) at least one freely-accessible electrode body (2, 22) is attached, which can be supplied with electrical energy via at least one electrical conductor (3) extending in the longitudinal direction of the probe, wherein the electrode body has a dome-shaped electrode surface and cross-sectional areas oriented orthogonally to the longitudinal direction of the probe (z) of the probe, the surface areas of which increase continuously along a first axial section containing the distal dome end of the electrode body with increasing distance from the distal dome end, wherein the cross-sectional areas are each bounded by a peripheral edge that is continuously differentiable at every point, wherein the probe has a bending strength, at least in the region of the electrode body connected to the probe on the distal side, which ensures the dimensional stability of the probe under the action of a bending moment of at least 0.1 Nm acting on the electrode body transversely to the longitudinal extension of the probe, and wherein a spatula- or shovel-shaped molded body is attached distally to the rigid hollow cannula, to which the freely-accessible electrode body is attached distally.

13. Device according to claim 12, wherein the molded body consists of an electrically insulating material, to which the freely-accessible electrode body is directly attached on the distal side, or wherein the molded body consists of an electrically conductive material, to which the freely-accessible electrode body is attached on the distal side via an electrical insulator.

14. Device according to claim 12 or 13, wherein the molded body is shaped like a shovel, with a flattened electrode body surface that has a straight surface section on the proximal side, which is connected to a convexly-curved surface section on the distal side, the other flattened electrode body surface is convexly-curved, and wherein the freely-accessible electrode body adjoins the molded body on the medial or immediate distal side in the form of a bead-shaped and rounded thickening.

15. Device according to any one of claims 12 to 14, wherein the molded body has a cross-section which, at least in some areas, has the outer shape of a figure eight.