Patent Application
20230022232
The invention relates to a device for the enucleation of intracorporeal tissue regions, in particular the prostate, with a probe at whose distal end at least one freely accessible electrode body line is mounted, to which electrical energy can be applied via at least one electrical line running in the longitudinal extent of the probe.
Devices for the enucleation of intracorporeal tissue regions are mainly used for the purpose of treating benign enlargements of the prostate, known as benign prostate hyperplasia (BHP). Widely used for this are endoscopic instruments which in a minimally invasive manner are positioned transurethrally, i.e. through the urethra, intracorporeally at the location of the prostate to be treated in order to completely or incompletely remove benignly enlarged areas of the prostate. Used for performing the minimally invasive surgical procedure, also known as transurethral resection of the prostate, TURP in short, are so-called resectoscopes (see, for example, document DE 935391 B.) which for the purpose of local tissue removal comprise at least one working channel, through which can be fed a probe-like electrode catheter that has a distal electrode tip designed in the form of a loop, to which HF alternating current can be applied, resulting in heating of the electrode loop with which local thermally-induced tissue layer separation is possible. In order to ensure good optical monitoring during the tissue ablation, during the operation irrigation fluid is continuously applied and removed by suction via the resectoscope. The irrigation fluid is electrolyte-free in the case of so-called monopolar resections, whereas when using bipolar resectoscopes, isotonic saline solutions are deployed. HF mono- or bipolar resection of the prostate is seen as the gold standard in the treatment of BPH, even though it also has some disadvantages. Thus, with this treatment method, the resection of the glandular tissue benignly forming on the prostate is not usually complete and the procedure times required for tissue removal are long, particularly in the case of larger adenomas, and result in a considerable burden for the patient. Moreover, in some cases, the required irrigation of the tissue region being treated in the context of a monopolar resectoscopy with hypotonic irrigation solution leads to so-called TUR syndrome that results in ingressions into the vascular system and can cause possible complications such as pulmonary oedema, cerebral oedema, haemolysis and kidney failure.
Newer transurethral endoscopic enucleation techniques using laser-based resectoscopes, in particular using so-called holmium laser enucleation of the prostate, HoLEP in short, show better clinical results. In particular, as well as the treatment of very large adenomas, laser-based prostate enucleation allows layer-specific preparation, through which sparing layer separation between the prostate capsule and the enlarged internal gland or the adenoma is made possible. This procedure allows for particularly low-bleeding surgery in comparison with conventional methods based on the use of the aforementioned HF electrode loops. In contrast to the known conventional techniques, laser-based enucleation offers complete, fine-tissue separation and preparation of the tissue to be removed.
Due to the high costs, and the large volume of the devices, which have to be positioned accordingly in the operating room, it is only possible to provide and accommodate such systems at a small number of locations.
Document U.S. Pat. No. 10,470,837 describes a device and a method of treating rhinitis, that is chronic inflammation of the nasal mucous membrane, with which it is possible to ablate the nerve branch from the nasal nerves located in the posterior nasal cavity. A flexibly designed surgical probe enables it to be introduced and positioned in the submucosal space of a lateral nasal wall, where neuroablation of the posterior nasal nerve can be performed with the surgical probe. At its distal probe tip, the probe device comprises a lamp that shines through the submucosal tissue, making it possible for the surgeon to visualize the submucosal position of the distal end of the surgical probe from the interior of the nasal cavity. In one form of embodiment the probe tip is rounded and comprises an HF electrode assembly for the local generation of Joule heating.
Document DE 696 36 885 T2 discloses a surgical system with a cooled electrode tip. Integrated along the hollow electrode body, the distal end, which can be pointed or rounded, is a cooling system through which the amount of heat that can be applied by the electrode assembly on the distal area to the intracorporeal environment can be controlled, in order to avoid overheating effects.
Document DE 10 2015 119 694 A1 describes an electrosurgical system for the resection of body tissue that comprises at least two electrodes, to which high-voltage pulses can be applied by means of a high-voltage supply unit, for the purpose of brief gas bubble formation within a fluid in contact with the electrosurgical system.
The electrode stimulation probe set out in document DE 88 07 820 U1 is shaped and sized to match the anatomical features of the human sphincter region for the treatment of bladder or anal incontinence as well as hemorrhoids.
Document WO 02/098312 A2 discloses a probe arrangement with a distal probe tip, in the form of a puncture needle tip, for the electrothermal coagulation of tissue, which has two electrodes, one of which is connected to an internal conductor and the other to an external conductor. Internal and external conductors of the probe arrangement are electrically insulated from each other. The inner conductor is also selected so that the bending stiffness of the probe arrangement is increased.
DE 10 2017 100 409 A1 discloses an electrosurgical device which comprises a handle on which is mounted a shaft that is rotatable in a controlled manner.
The invention is a device for the enucleation of intracorporeal tissue regions, in particular of the prostate, with a probe at whose distal end at least one freely accessible electrode body is mounted to which electrical energy can be applied via at least one electrical line running in the longitudinal extent of the probe, in such a way that the disadvantages that were previously linked to HF mono- or bipolar resection of the prostate are avoided and comparable surgical properties and results to those achievable with laser-based endoscopic enucleation of the prostate, EEP in short, should be made possible. More particularly, a cost-effective and qualitatively equivalent alternative to complex laser-based EEP is to be created.
In accordance with the invention, the device for the enucleation of intracorporeal tissue regions, particularly for treating benign prostate hyperplasia, has a dome-shaped electrode surface and has cross-sectional surfaces which are orientated orthogonally to the longitudinal extent of the probe and whose surface areas along a first axial portion which contains the distal dome end of the electrode body, increase continuously as the distance from the distal dome end increases. In addition, the cross-sectional surfaces are each limited by a peripheral edge, each point of which is always differentiable, that is smooth and has no edges or corners. Furthermore, at least in the area of the electrode body distally connected to the probe, the probe has a bending stiffness that under the effect of a bending moment of at least 0.1 Nm acting on the electrode body transversely to the longitudinal extent of the probe, guarantees dimensional stability of the probe.
The device according to the invention is based on largely completely replicating the handling and therapeutic effect of a laser catheter designed for the purpose of prostate enucleation, through a probe that is capable of electrical ablation and coagulation of tissue layers or regions and can also be used in connection with a resectoscope.
For this, the dome-shaped electrode body mounted on the distal end of the probe with the electrode body surface having sliding properties, that are completely smooth and without undercuts or edges, so that through distal advancing or lateral movement of the probe by way of the dome-shaped, smoothly configured electrode body, as atraumatic and blunt preparation of the tissue regions to be treated as possible is enabled. Through small and distal or lateral advancement, the dome-shaped electrode body is able to undo or separate tissue layers through a purely mechanical displacement process without, or without appreciable, lesion formation.
The probe configuration according to the invention is, among other things, based on the knowledge that the sparing, laser-based tissue separation process, that is HoLEP, is essentially dependent on the beam quality and impulse of the laser beam emitted from the laser catheter end. In addition to the beam power, the beam diameter, the beam divergence as well as 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, possibly the resulting formation of gas bubbles, and the tissue regions to be penetrated or prepared for the purpose of precise, time-efficient and sparing separation of the adenoma from the prostate.
High-quality laser beams exhibit a minimal beam divergence and have a beam intensity distribution along the beam cross-section in the form of a Gaussian curve, for which reason such laser beams are also known as Gaussian beams. According to current knowledge, this spatial beam intensity distribution and the specific pattern of the spatial energy distribution at the site of the energy application appear to be the preconditions for the advantages associated with laser-based prostate enucleation, which forms the inspiration and basis for the spatial design of the electrode surface, in accordance with the invention, of the electrode body mounted on the distal end of the probe.
The dome-shaped design of the electrode body is, among other things, inspired and motivated by the spatial shape of the radiation intensity profile of a Gaussian beam, and through sparing distal or lateral movement of the probe, allows the blunt preparation of tissue regions or layers. As the electrode body can also be supplied with electrical energy via at least one electrical line, the tissue can, if necessary, also be at least one of severed, ablated and coagulated with electrical support.
The electrode body, which is preferably made of a metal or metal alloy, is either a monopolar electrode connected with one electrical line running along the probe, or a bipolar electrode connected with two electrical lines running along the probe. The innovative probe can be used in conventional resectoscopes and can be connected to HF devices normally present in the operating room. The device according to the invention allows precise, time-efficient and sparing treatment of the prostate through the urethra and, as in the case of laser-based resectoscopes, increases the operative safety and is able to significantly reduce the complication rates in comparison with conventional electrical prostate resection methods (TURP). The device according to the invention is also cost-effective and has the potential for positive and health economic effects on the entire health care system.
Preferably, the dome-shaped electrode surface of the electrode body at least along the first axial portion is replicated as a spatial radiation intensity distribution of a laser beam with a Gaussian intensity distribution, a paraboloid or ellipsoid. Also conceivable and implementable are spatial shapes diverging therefrom, in which the cross-sectional surfaces of the electrode body along each first axial portion are each surrounded by a peripheral edge, which is either exclusively curved or has curved and straight peripheral edge sections, wherein the transitions from curved to straight peripheral edge sections are smooth, that is continuously differentiable. The described curved design allows the operator to work in a preferred direction through rotating the instrument.
Conversely, looking at the longitudinal sections through the electrode body orientated orthogonally to the individual cross-sectional surfaces, a preferred embodiment of the electrode body exclusively has longitudinal sections, which are each delimited by a peripheral contour, also continuously differentiable at each location, that is are smooth in design. Preferably, the peripheral contours delimiting the individual longitudinal sections are described by a pitch circle, a parabola, a partial ellipse or a partial oval. An essential characteristic of the electrode surface designed in a dome-shape in accordance with the invention, is its smooth, outwardly appearing shape, which is suitable for separating tissue regions, in particular tissue layers, in a sparing, mechanical displacement process determined by the shape of the electrode body, in a manner that is lesion-free or largely lesion-free. Sharp-edged surface contours, or contours with small radii, as are usual in conventional electrode loops, are expressly ruled out for the shaping of the electrode body, in order to reach or mechanically advance between two anatomical tissue layers by way of the electrode body in as lesion-free a manner as possible.
In a further preferred form of embodiment, in the area of its distal end, the dome-shaped electrode body has a mamilla-like, also smooth and dome-shaped projection through which the mechanical separation process is sparingly supported when distally advancing the probe designed in accordance with the invention. Further explanations in relation to this can gleaned by way of the following illustrations.
Proximally adjoining the smooth, dome-shaped electrode body, is a second axial portion, along which the cross-sectional surfaces orientated orthogonally to the longitudinal extent of the electrode body remain the same as the distance from the distal dome end increases. Preferably the cross-sectional surfaces along the second axial portion are circular so that in this area the electrode body takes on a straight cylindrical outer shape.
The electrode in accordance with the invention is rigidly connected to the probe which is preferably configured as a hollow cannula and is capable of transmitting axial thrust or pressure forces as well as bending forces. The rigid joining of the electrode body on the hollow cannula preferably takes place by way of a biocompatible, electrically insulating joint in the form of a mechanical connecting piece, made, for example, of ceramic or glass or an epoxide resin-based cast component, which has solidified for connection purposes.
The probe, configured as a hollow cannula, also possesses high bending strength in order to withstand mechanical loads acting on the electrode body transversely to the longitudinal extent of the probe without any changes in shape. Such transverse leads can occur, for example, if the operator moves the electrode body laterally or perpendicularly to the longitudinal extent of the probe in order to remove or separate tissue. In this case, no or only minimal deformations, must occur, preferably along the entire probe, but at least in the distal region of the probe, that extends out of the resectoscope on the distal side for the purpose of blunt preparation. In order to ensure dimensional stability, it is evident to produce the probe, in the form of a hollow cannula, of a metallic material, for example instrument steel, or a robust, rigid, preferably fiber-reinforced plastic with a suitably thickly selected hollow cannula wall thickness.
Thus, at least in the distal region, the probe has a stiffness or bending stiffness that is such that under the effect of a bending moment on the probe resulting from a force acting on the electrode body transversely to the longitudinal extent of the probe while the probe is mechanically firmly clamped in at distance of at least 30 mm from the distal probe tip—which corresponds to typical probe guiding along and through a resectoscope—the distal probe tip is deflected a maximum of 2 mm transversely to the longitudinal extent of the probe, and in no case does plastic deformation of the probe occur. With a deflection of 2 mm, the applied force is measured, and the bending moment (F×1) is calculated. The probe is designed in such a way, that with a bending moment of 0.1 Nm, preferably of at least 0.2 Nm, particularly preferably of at least 0.3 Nm, the above requirements for the dimensional stability of the probe remain guaranteed.
Preferably all surfaces, that is both the surface of the electrode body and that of the joint, as well as of the proximally adjoining rigid hollow cannula are designed to be low-friction, providing a smooth surface and surface sliding. It is useful for at least the electrode surface of the electrode body to be polished or honed.
The device according to the invention can, in parts or completely, be provided with a surface finish, preferably in the form of a coating, that increases sliding ability. The coating may be, for example, of PTFE, polyurethane, polysiloxane or a hydrogel, or polymer with slide resistance-reducing additives, or a combination thereof.
Through the mechanically stiff or rigid connection between the hollow cannula, joint and electrode body, mechanical force transmission is possible along the probe in the axial and lateral direction onto the electrode body, with which sparing and targeted tissue separation in the form of atraumatic, blunt preparation becomes possible. The term “blunt preparation” is taken to mean forcing apart two anatomical structures that are connected to each other by at least one of a connective tissue and a vascularised or avascularised layer. In this way an artificial space is created which can be formed under normal biophysiological and anatomical conditions. The blunt preparation process is exclusively initiated by mechanical movement in the distally forward direction as well as at least one of lateral swinging to and fro and rotary movements of the electrode body about the longitudinal axis of the probe or hollow cannula by an operator in the intracorporeal target tissue region. If required, the electrically conductive electrode body can, through being supplied with high-frequency current, develop at least one of an additional cutting, ablation and/or coagulation effect within the tissue region.
In order for the operator to be able to carry out the process of pushing apart two anatomical layer structures in an as tissue-sparing a manner as possible, effectively but finely dosed and directionally selectively, spatial shapes for embodying the electrode body along the first electrode section are particularly suitable that deviate from axial symmetry about the longitudinal axis of the probe and have two-dimensional cross-sectional shapes that are formed flattened along one of two cross-sectional axes orientated orthogonally to each other, like the shape of a spatula. Through the flattening of the otherwise round, that is edge-free electrode body shape, flat pushing apart of two anatomical layer structures is better possible, in that the respectively flattened electrode body surfaces which are opposite each other along a cross-sectional axis, are guided in parallel between the layer structures to be separated when advancing the probe.
Preferably, but not necessarily, the flattened electrode body surfaces are each symmetrical to a cross-sectional axis, that is both electrode body surfaces have at least one flat surface area or both electrode bodies have at least one convexly curved surface area. It is also conceivable that one electrode body surface is convexly curved and the other electrode body surface is concavely curved, or that 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.
In the case of asymmetrical flattening of the electrode body, one of the two electrode body surfaces preferably has a curved surface shape in the longitudinal extent to the longitudinal axis of the probe, along which the at least one center of curvature is contained. In contrast, the opposite electrode body surface is preferably largely straight. Of course, flattened electrode body surface shapes deviating therefore are conceivable, which allow effective advancing between and pushing apart of two tissue layers.
Through asymmetrical flattening of the electrode body, through alternating bidirectional rotation of the electrode body about the longitudinal axis of the probe, tissue-displacing tipping movements acting on the tissue surroundings become possible for the operator when advancing the probe, which can in some cases support the process of pushing apart two anatomical layer structures.
In addition, asymmetrical flattening of the electrode body, allows the possibility of asymmetrically designing electrode contact surfaces that come into contact with the tissue.
For example, the largely straight, flattened electrode body shape set out in the previous example of embodiment can be designed to be electrically conductive, whereas the opposite, curved electrode body shape is at least not completely electrically conductive and, for example, is locally covered with an electrically insulating layer, or vice versa.
The device according to the invention is particularly suitable for surgical use in connection with a resectoscope which is known per se, and in addition to a working channel for feeding through the probe according to the invention, envisages further at least one of working and irrigation channels, through which the surgeon can optically monitor the performance of a transurethral prostate enucleation. Preferably, for the purpose of a centered and position-defined guiding of the probe along the working channel of the resectoscope, at least one guide sleeve is applied along the hollow cannula, which both acts as a centering and sliding element and also as a feedthrough element for at least one further medical instrument in parallel to the probe through the working channel.
As an example, the invention will be described below, without restricting the general inventive concept, by way of examples of embodiment with reference to the drawings. In these:
The metallic electrode body 2 is firmly connected to probe 1, designed as a hollow cylinder, by way of a biocompatible, electrically insulating joint 7. The joint 7 is, for example, designed as a molded body for connection between the electrode body and the hollow cannula.
The curvature of the electrode surface of the electrode body 2 in the first axial portion 5 is constructively determined and optimally selected for the process of blunt preparation. In addition, preferred electrode surface geometries for creating the electrode body 2 are described.
In
The electrode bodies 2 shown in
The cross-sectional surfaces of the electrode bodies 2 which respectively are spherically formed along the first axial portion 5, correspond to circular areas each with continuously increasing circle diameters up to a circle diameter that corresponds to the diameter of the straight cylindrical outer shape along the second axial portion 6. The associated longitudinal sections through the electrode body 2 thus represent semicircular areas in the first axial portion 5.
The shape of the dome-shaped electrode body 2 can diverge from the spherical dome-shaped design in accordance with the forms of embodiment in
In the case of the cross-sectional shapes in accordance with
In the case of the cross-sectional shapes A1 to A5 illustrated in
In this case too, the elliptical cross-sectional shaped morphologically transition into a circular cross-section A6, which corresponds to the outer hollow cannula cross-section of the probe 1.
The distal end 17 of the spatula-shaped, flattened electrode body 2 has a distally rounded contour, to which two electrode surfaces 14, 15 seamlessly adjoin. The distal end 17 is also arranged eccentrically with regard to the longitudinal axis of the probe 18. The electrode surface 15 ends in a largely contour-maintaining manner on the outer wall of the proximally extending electrode body 2. The electrode surface 14, on the other hand, is curved in a shovel-like manner and radially seamlessly adjoins the face edge of the ceramic sleeve body 16, which is designed to maintain the contours of the shovel shape.
In practical application of the probe, the rounded end 17 ensures sparing displacement and separation of two tissue layers. The shape of the two electrode surfaces 14 and 15 as well as the proximally adjoining face-side contours of the ceramic sleeve body 16 allow for spatial distancing of the separated tissue regions.
In
An alternative cross-sectional shape is illustrated in
A variant of embodiment modified with regard to the embodiment shown above in
In all the examples of embodiment illustrated above, the entire surface area of the electrode body 2 is at least one of smoothly polished and honed, at least along area B. Preferably the electrode surface area of electrode body 2, the ceramic sleeve body 16 and the probe 1 are covered with a low-friction coating, preferably with a coating containing PTFE, TPU, polysiloxane or hydrogel.
The electrode body 2, comprising an electrically conductive and dimensionally stable material, preferably a metal or a metal alloy, is enclosed in a mechanically stable, torsion-free and rigid as well as electrically insulated manner within the hollow cannula 1 as well as the adjoining ceramic sleeve body 16. Area B of the electrode body 2, which distally projects from the ceramic sleeve body 16, is spoon-like or shovel-like in design. At its distal end 17, the electrode body 2 has a bulbous and rounded thickening 22. Proximally, the electrode surface 15 flushly adjoins the outer contour of the ceramic sleeve body 16. Via a section 1 the electrode surface 15 extends essentially in parallel, rectilinearly to the longitudinal extent of the ceramic sleeve body 16. Subsequent to this, the electrode surface 15 is convexly curved and at the distal end 17 merges into the bulbous and rounded thickening 22.
The electrode surface 14 is essential concavely formed in a spoon-like manner and on both of its longitudinal sides has bulbous edge contours 23, whose spatial shape can be seen in the cross-sectional view according to 10b along section plane B-B.
Through the bilateral superelevations on the electrode surface 14 resulting from the bulbous edge contours 23 vis-a-vis the concave recess arranged centrally to the longitudinal axis of the probe, this shape provides the electrode body 2 with increased dimensional or bending strength, particularly in the case of forces acting transversely to the longitudinal extent of the probe. The surface contour of the electrode surface 14 resembles the outer contour of a figure eight, whereas the opposite electrode surface 15 is flat.
In the distal area of the bulbous and rounded thickening 22, along the section line C-C visible in
The radial extent or spatial expansion of the electrode body 5, does not project beyond the radial dimension of the hollow cannula 1, which is defined by the outer diameter b, so that it is ensured that the entire probe can be fed unhindered through a working channel of a resectoscope which is dimensionally matched to the hollow cannula.
The cross-sectional view according to
The probe illustrated in
Alternatively to the embodiment of the insulating body 24,
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 220 537.2 | Dec 2019 | DE | national |
Reference is made to PCT/EP2020/087639 filed Dec. 22, 2020, designating the United States, and German Application No. 10 2019 220 537.2 filed Dec. 23, 2019, which are incorporated herein by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/087639 | 12/22/2020 | WO |
