The invention relates generally to medical probes, with a preferred version of the invention relating more specifically to an implantable electrode probe with a tubular, flexible probe body, an electrode mounted at the distal end of the probe body, and an electrical supply line guided in the probe body to the electrode.
Electrode probes are routinely used, for example, as coronary pacemaker electrodes. They are variously described in patent literature, with examples being the patent publications DE 10 2005 039 040 A1, DE 198 00 697 A1, DE 20 2006 020 517 U1 and EP 88730200.8.
Probes that can be implanted in the body, especially electrode probes, should have a probe diameter as small as possible to ensure comfortable passage through the insertion site and blood vessels up to the desired implant site, and to better enable the use of small insertion tools. However, probes with small diameter increase the danger of causing unwanted perforation of body tissue at the implant site.
As known in the field, active ingredients can be administered by the probe, particularly an electrode probe, at the implant site. For example, in U.S. Pat. No. 5,571,163 A and U.S. Pat. No. 5,324,324 A1 it is proposed that the electrode tip be coated with anti-inflammatory medications in order to locally counteract the tissue irritation caused by the probe. In the case of electrode probes with a relatively small probe diameter, the small probe surface disadvantageously limits the area available for administering the active ingredient. Additionally, if the same amount of active ingredient is to be used on a smaller probe diameter, the reservoir of active ingredient extends over a larger length of the probe so that portions of the active ingredient are released at a relatively far distance from the implant site, which can reduce the therapeutic utility of the active ingredient.
Therefore, there is a desire for a solution to the competing objectives of obtaining an optimal electrode probe diameter for ease of implantability of the probe, and a suitable configuration for local discharge of active ingredient by the probe.
An objective of the invention is to provide an implantable electrode probe that has a small probe diameter in order to better ensure comfortable implantation, but also offers high safety against perforation, and also makes efficient discharge of active ingredient possible at the implant site, i.e. at locations at which the probe can irritate tissue. The invention involves an electrode probe for medical applications—e.g., a coronary pacemaker electrode, an electrode for nerve stimulation, an electrode for the measurement of brain potential, or the like—includes a tubular, flexible probe body; an electrode mounted at the distal end of the probe body (for example, a tip electrode); and an electrical supply line that is guided in the body of the probe. One or more electrical contacts can be mounted along the probe body. At least a part of the distal end section of the probe body—preferably at a part directly next to the electrode—can be transformed by a displacement mechanism between a first radially narrower condition and a second radially broader condition. In the second condition, the distal end section of the probe body is radially broadened in relation to the remainder of the probe body and the electrode.
The electrode probe can thus be implanted with a thin distal end section, allowing more comfortable passage through the insertion gateway and blood vessels owing to the smaller radial dimension of the distal end section of the probe body. On the other hand, the distal end section of the probe body can be radially broadened at the implant site, thereby deterring tissue perforation and also providing a relatively large surface for local discharge of an active ingredient at the implant site. In addition, because of the spatial proximity (or contact) of the broadened area at the distal end section to the implant site, the active ingredient can be discharged directly at the site of the tissue irritation, achieving high therapeutic efficiency. Moreover, compared to a distal end section of the probe body that is not broadened, a greater amount of active ingredient can be provided at or close to the implant site.
Throughout this document, the term “axial” will generally be used to describe directions along the length of the electrode body (inner tube), and the term “radial” will generally be used to describe directions perpendicular to the length of the electrode body.
In a preferred version of the electrode probe, the electrode mounted at the distal end of the probe body is mechanically coupled at least in an axial direction with the distal end section of the probe body, for example, by being connected with and/or engaged behind the distal end section, and the electrical supply line to the electrode is displaceable in an axial direction relative to the probe body. The distal end section of the probe body is designed in such a way that at least a part of the distal end section can be deformed into a radially broadened collar by a force that is transmitted by the electrode to the distal end section (for example, by manually effecting relative motion between the electrical supply line and the probe body). The distal end section is resiliently flexible and/or elastic to effect the deformation into the broadened state. Thus, the electrode probe can be implanted at the implant site with a non-broadened distal end section, and by then generating relative motion between the electric supply line and the probe body, the distal end section can be radially broadened.
In an advantageous version of the electrode probe, a casing surrounds at least a portion of the probe body, and is mechanically coupled to the distal end section in such a way that the distal end section can be deformed into the radially broadened collar as a result of relative motion between the electrical supply line and the casing (as by pushing the collar forwardly with respect to the supply line, and/or by pulling the supply line rearwardly with respect to the casing).
The electrode may be designed as a screw-in electrode for screwing into body tissue, for example, heart tissue, whereby rotation of the electrical supply line can displace the electrode between a passive setting within the probe body and an active setting at least partially outside of the probe body. Screw-in anchoring of an electrode is known, for example, from DE 20 2006 020 517 U1. At least a portion of the distal end section of the probe body is deformable into a radially broadened collar upon screwing the electrode into body tissue as the result of forces exerted on the deformable distal end section. Thus, the collar is formed in the distal end section of the probe body during screwing in of the electrode. The electrode probe can be positioned at the implant site with a non-broadened distal end section, and the distal end section can be radially broadened by screwing the electrode into the body tissue.
A screw-in electrode as described above can be displaced between the passive setting and the active setting by cooperating with a thrust bearing (“pitch provider”) mounted in the area of the distal end section at the probe body, during rotation of the supply line. Such a pitch provider is described in the aforementioned DE 20 2006 020 517 U1. The distal end section is designed in such a way that it can be deformed into a radially broadened collar by interaction between the screw-in electrode and the thrust bearing upon rotation of the supply line. The collar can thereby be easily and automatically formed in the distal end section of the probe body by rotating the supply line, with the collar being formed by the pressure exerted by the body tissue on the distal end section, and by the force transmitted by the thrust bearing to the distal end section. The electrode probe can therefore be positioned at the implant site with a non-broadened distal end section which is then radially broadened during anchoring by screwing the electrode into the body tissue, and by the transmission of force to the thrust bearing.
In an advantageous version of the electrode probe, at least a portion of the distal end section of the probe body bears through-holes which define lamellae (e.g., strips or fingers) extending in the axial direction, and which deploy into a radially broadened state. This can achieve simple formation of the collar with a relatively large radial broadened area.
In another advantageous version of the electrode probe, the distal end section of the probe body has several broadening components on its outer surface that can be displaced between a passive setting in which they abut the outer surface at the distal end section, and an active setting in which they extend from the distal end section in the radial direction. The broadening components may be coupled with a mechanical pre-loading tool, for example, a spring tool, that pre-loads the components into their active setting. A sleeve-shaped insertion tool can be used to force the broadening elements into their passive position, and after implantation, the insertion tool can be removed from the implanted electrode probe to move the broadening elements into their active setting.
The outer surface of the distal end section of the probe body can be provided with at least one active ingredient to be discharged into the body tissue, as by providing the active ingredient as a coating of the outer surface of the distal end section. This can achieve targeted local discharge of active ingredient near or in contact with the body tissue at the implantation site, whereby the therapeutic effectiveness of the discharged active ingredient is improved.
The distal end section of the probe body may include a discharge device connected with at least one active ingredient reservoir for discharging at least one active ingredient into the body tissue. This can also achieve targeted local discharge of active ingredient near or in contact with the body tissue at the implant site.
Alternatively or additionally, the electrode may be provided with a discharge device connected with at least one active ingredient reservoir for discharging at least one active ingredient into the body tissue at the implantation site. This can also provide targeted local discharge of active ingredient near or rather in contact with the body tissue at the implant site to enhance the therapeutic effectiveness of the discharged active ingredient. The active ingredient reservoir(s) can be compressed by a displaceable piston or other tool in order to effect transport of the active ingredient from the active ingredient reservoir to the discharge device. The compression means for compressing the active ingredient reservoir may be displaceable by coupling a swellable material to the compression means. A wall of the compartment for housing the swellable material may have one or more permeable openings for admitting liquid for swelling the swellable material. The available area of the liquid-admitting openings may be varied as the compression means displaces, such that the rate of swelling (and thus the motion of the compression means) may be varied with the position of the compression means.
Where a reservoir of active ingredient is provided, it is useful if the reservoir is housed in the probe body.
If a discharge device for discharging at least one active ingredient is used, it can be useful if the reservoir of active ingredient is in fluid connection with an electrically operated pump for supplying the active ingredient to the active ingredient discharge device.
Exemplary versions of the invention are now explained in detail with reference to the accompanying drawings, wherein the same or functionally similar elements are labeled with the same legend. Shown are:
A first exemplary version of the electrode probe is schematically illustrated in
At a facing surface 5 or otherwise on the distal end section 3 of the probe body 2, an at least substantially half-spherical tip electrode 6 is engaged radially about the distal end of the probe body 2, so that a force can be transmitted in the axial direction between the tip electrode 6 and the distal end 3 of the probe body 2. The probe body 2 forms a lumen housing an interior conductor 7, and a first isolation sleeve 8 made of an insulating material surrounds the conductor 7, wherein the conductor 7 and sleeve 8 can jointly be considered to be the “inner part” of the probe body 2. The interior conductor 7, which may be provided as a wire helix or in other forms, makes contact with the tip electrode 6 as an electrical supply line.
An exterior conductor 9, which can also be designed (for example) in the form of a wire helix, is surrounded by an isolation sleeve 10 (only partially shown) and extends as an electrical supply line to make contact with a ring electrode 11 located proximal to the distal end section 3. As illustrated in
The interior part of the probe body 2 (the conductor 7 and/or sleeve 8, as defined above) is displaceable relative to the exterior part of the probe body 2 (the exterior conductor 9 and/or the second isolation sleeve 10) in an area between the distal end section 3 and the proximal end section 4. At the distal end section 3 of the probe body 2, the tip electrode 6 is connected with the probe body 2. At the area of the proximal section 4, the interior part of the probe body 2 may be connected to the exterior part of the probe body 2.
In the area of the distal end section 3, a number of anchor elements 12 are distributed circumferentially about the exterior surface of the probe body 2. These anchor elements 12 may take the form of tips (“tines”), and may be oriented at an angle of, for example, approximately 30° to the proximal end section 4 of the probe body 2. The anchoring elements 12 may serve in a known manner for so-called passive anchoring of the electrode probe 1 in the ventricular trabecular meshwork.
As is shown in
The exterior surface of the distal end section 3 of the probe body 2 is preferably coated with at least one pharmaceutically active substance (active ingredient), which can be discharged to the surrounding coronary tissue. The active ingredient might only be applied to that part of collar 14 that is aligned toward the coronary tissue. For purposes of dispensing the active ingredient, the distal end section 3 is preferably formed of (for example) a biocompatible polymer such as (again for example) silicone rubber and polyurethane, or of a material that can be resorbed and which releases the active ingredient on a delayed basis during decomposition. In principle, the distal end section 3 can be coated with any active ingredient, with preferred ingredients being anti-inflammatory steroids (glucocorticoids), especially alclomethason, amcinonide, beclomethasone, betamethasone, budenoside, ciclesonide, clobetasol, clobetasone, clocortolone, cloprednol, cortisol, cortisone, deflazacort, desonide, desoximethasone, dexamethasone, diflorasone, diflucortolone, fludroxycortide, flumetasone, flunisolide, fluocinolon, fluocinonide, fluocortin, fluocortolone, fluorometholone, fluprednides, fluticasone, halcinonide, halometasone, hydrocortisone, medrysone, methylprednisolone, mometasone, prednicarbate, prednisolone, prednisone, prednylides, rimexolone, tixocortol, triamcinolone, as well as derivatives thereof. Derivatization can be performed especially as aceponate, acetate, acetate-propionate, acetonide, benzoate, buteprate, butyrate, butyrate-propionate, diacetate, dihydrogenphosphate, dipropionate, ethyl carbonate propionate, hydrogensuccinate, hexacetonide, isonicotinate, palmitate, phosphate, pivalate, propionate, sodiumphosphate and valerate. The active ingredient can be dissolved or suspended in a matrix. A possible dose is, for example, in the range of 0.01 to 1,000 mg.
The electrode probe 1 schematically shown in
It is also possible to apply a cladding to the probe body 2 that is connected with the distal end section 3 of the probe body 2, whereby displacement of the distal end section 3 in a proximal direction forms the circular collar 14 relative to the interior part. Fixation of the collar 14 into its expanded form could be accomplished by affixing the interior and exterior parts of the probe body 2 together, as by use of a crimping/fixation sleeve (not shown) to which electrode probe 1 is mounted near the pacemaker pocket.
It would also be possible to create a spring tool consisting of, for example, nitinol in the distal end section 3 of the collar 14, whereby the electrode probe 1 is implanted with an insertion tool which is removed after the implantation so that the collar 14 can expand subject to the effect of the spring tool.
The distal end section 3 of the probe body 2 is provided with a number of axial strips or lamellae 16 distributed in the circumferential direction. To form the lamellae 16, slots 15 are defined along the distal section 3. If the exterior piece is then displaced in a distal direction relative to the interior piece, the lamellae 16 then protrude to form the collar 14. Based on the lamellar structure of the distal end section 3, the collar 14 can be generated via application of a relatively small force, and the lamellae 16 can be deformed into a relatively broad collar 14 in the radial direction. As indicated by the arrow in
In
If the electrode probe 1 is anchored at the implant site by screwing in electrode 19 into coronary tissue 21, the tissue exerts a proximally-oriented counter-force upon the distal facing surface 5 of the distal end section 3 of the probe body 2. Likewise, upon rotating screw-in electrode 19 out of the probe body 2, the thrust bearing 20 exerts a proximally-oriented force on the distal end section 3. Both effects contribute to deformation of the distal end section 3 into a radially broadened collar 14 during the screwing in of screw-in electrode 19, as illustrated in
The electrode probe 1 illustrated in
By coating an exterior surface 22 (
In
Alternatively, by displacing the exterior part over the interior part (as discussed above with respect to
The active ingredient reservoir 23 is defined by the housing wall 24, a piston 27, and an opposing distal facing surface 32. An active ingredient 31—for example, a steroid—can be discharged from the reservoir 23 through the pores 30 in the screw-in electrode 19. The piston 27 can be displaced within the housing wall 24 in the axial direction, and can be bounded on its side opposite the reservoir 23 with a swellable material 34 (
As illustrated in
Alternatively, the expanding compartment 28 could be loaded pneumatically or hydraulically with a pump. It would alternatively or additionally be possible to provide a non-pressurized passive diffuse discharge of active ingredient from the active ingredient reservoir 23, or discharge via an electrical potential, for example by an iontophoretic transport. Within the active ingredient reservoir 23, the active ingredient 31 can be present alone or embedded into a (possibly swellable) matrix.
In
In the variant shown in
In the variant shown in
In the variant shown in
In the variant shown in
In the variant shown in
In the variant shown in
In the variants shown in
The active ingredient used in the invention is preferably selected from the following classes of medications: antimicrobial, antimitotic, antimyotic, antineoplastic, antiphlogistic, antiproliferative, antithrombotic and vasodilatory substances.
Especially preferred active ingredients are triclosan, cephalosporin, aminoglycoside, nitrofurantoin, penicillins such as dicloxacillin, oxacillin as well as sulfonamide, metronidazol, 5-fluoruracil, cisplatin, vinblastine, vincristine, epothilone, endostatin, verapamil, statins such as mevastatin, cerivastatin, atorvastatin, simvastatin, fluvastatin, pitavastatin, pravastatin, rosuvastatin as well as lovastatin, angiostatin, angiopeptin, taxane as well as paclitaxel, immunosuppressives or immunomodulators as well as, for example, rapamycin or its derivatives such as biolimus, everolimus, deforloimus, novolimus, methotrexat, colchicine, flavopiridol, suramin, cyclosporin A, clotrimazole, flucytosin, griseofulvin, ketoconazole, miconazole, nystatin, terbinafine, steroides, sulfasalazine, heparin and its derivatives, urokinase, ppac, argatroban, aspirin, abciximab, synthetic antithrombin, bivalirudin, enoxoparin, hirudin, r-hirudin, protamine, prourokinase, streptokinase, warfarin, flavonoids such as 7,3′,4′-trimethoxyflavone, sartane as well as dipyramidol, trapidil, and nitroprusside.
The active ingredients can be used individually, or combined in equal or various concentrations.
As has been explained above in regards to the exemplary versions, the invention provides perforation protection via a radially broadened structure in the distal end section of the probe body adjacent the electrode that is mounted at the distal end of the electrode probe. Therapeutically efficient, local discharge of active ingredients at the site of tissue irritation can be achieved by the discharge of active ingredients via the radially broadened structures, and/or via the electrode mounted at the distal end of the electrode probe. Particularly when a screw-in electrode is used, traumatization of the coronary tissue can occur as a result of the insertion of the screw-in electrode, particularly at the tissue surrounding the implant. As a result of a discharge of anti-inflammatory active ingredients by the screw-in electrode, the active ingredients are placed at the target location. In addition to faster application, higher concentrations of active ingredients can be achieved in the target tissue, as the diffusion from the endocardium into the myocardium takes place on a delayed basis. Extraction of the released active ingredient by the circulation of blood in the heart is also prevented. Extraction of the released active ingredients tend to be most pronounced in the first days after the implantation, as the tip of the electrode is still exposed or not yet grown in. At the same time, however, inflammation is at its peak.
It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and versions are possible in light of the foregoing discussion. The disclosed examples and versions are presented for purposes of illustration only. Therefore, it is the intent to cover all modifications and alternate versions that are literally or equivalently encompassed by the following claims.
This application claims priority under 35 USC §119(e) to U.S. Provisional Patent Application 61/219,434 filed 23 Jun. 2009, the entirety of which is incorporated by reference herein.
Number | Date | Country | |
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61219434 | Jun 2009 | US |