Multilumen Body for a Medical Device

Abstract

A multilumen body for a medical device, comprising a first tubular element and a second tubular element, which is arranged in the first tubular element and which is in contact with the first tubular element at least in sections and movable relative to the first tubular element, an inner surface of the first tubular element having a first profile and/or an outer surface of the second tubular element having a second profile so that the contact surface between the first tubular element and the second tubular element is smaller than without the first profile and/or without the second profile. The multilumen body is characterized in that the first profile and/or the second profile include a plurality of alternating elevations and depressions, wherein a maximum distance between two neighboring elevations is 100 μm.

Claims

1. A multilumen body for a medical device, comprising a first tubular element and a second tubular element, which is arranged in the first tubular element and which is in contact with the first tubular element at least in sections and movable relative to the first tubular element, an inner surface of the first tubular element having a first profile and/or an outer surface of the second tubular element having a second profile so that the contact surface between the first tubular element and the second tubular element is smaller than without the first profile and/or without the second profile, wherein the first profile and/or the second profile include a plurality of alternating elevations and depressions, a maximum distance between two neighboring elevations being 100 μm.

2. The multilumen body according to claim 1, wherein the first profile and/or the second profile have a corrugated shape in the cross-section of the multilumen body.

3. The multilumen body according to claim 1, wherein the elevations and depressions of the first profile and/or the elevations and depressions of the second profile extend from a proximal end of the multilumen body to a distal end of the multilumen body.

4. A multilumen body according to claim 1, wherein the elevations and depressions of the first profile and/or the elevations and depressions of the second profile extend in a linear or helical manner along a longitudinal extension direction of the multilumen body.

5. A multilumen body according to claim 1, wherein the second tubular element comprises at least one inner lumen, which is provided and configured to accommodate an electrical conductor.

6. A multilumen body according to claim 1, wherein the first tubular element and/or the second tubular element comprise at least one polymer, which is selected from the group consisting of polyurethanes, polyester urethanes, polyether urethanes, polycarbonate urethanes, polycarbonate polyurea urethanes, polydimethylsiloxane urethanes, polyisobutylene urethanes, polyisobutylene-based copolymers, polyether block amides, polyimides, fluorinated hydrocarbons, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene, tetrafluoroethylene, perfluoro, perfluoroalkoxy polymers, polysulfone, polyethylene, polypropylene, polyamides, and silicone.

7. A multilumen body according to claim 1, wherein the first tubular element comprises a thermoplastic material, and the second tubular element comprises silicone.

8. A multilumen body according to claim 1, wherein the multilumen body includes both the first profile and the second profile, the first profile and the second profile not engaging one another, but allowing a rotation of the second tubular element in the first tubular element.

9. A multilumen body according to claim 1, wherein the multilumen body includes both the first profile and the second profile, the first profile and the second profile having different orientations so that a punctiform contact pattern results between the first profile and the second profile.

10. A multilumen body according to claim 1, wherein an adhesive is situated in a space between the first tubular element and the second tubular element in a proximal end region of multilumen body and/or in a distal end region of the multilumen body, the adhesive preventing an ingress of a fluid from outside the multilumen body into the space between the first tubular element and the second tubular element.

11. A multilumen body according to claim 1, wherein the multilumen body is a shaft of a catheter.

12. A multilumen body according to claim 1, wherein the multilumen body is an implantable electrode.

13. A medical device, wherein a multilumen body according to claim 1.

14. The medical device according to claim 13, wherein the medical device is an implantable device for stimulating the human or animal heart, such as an implantable cardiac pacemaker or an implantable cardioverter/defibrillator, and the multilumen body is an implantable electrode of this implantable device.

15. A method for producing a multilumen body according to claim 1, comprising a first tubular element and a second tubular element, which is arranged in the first tubular element and which is in contact with the first tubular element at least in sections and movable relative to the first tubular element, an inner surface of the first tubular element having a first profile and/or an outer surface of the second tubular element having a second profile so that the contact surface between the first tubular element and the second tubular element is smaller than without the first profile and/or without the second profile, the method comprising: producing the first tubular element and/or the second tubular element by way of extrusion using an extrusion tool, the extrusion tool being designed so as to introduce the first profile into the first tubular element and/or the second profile into the second tubular element during the extrusion process, the first profile and/or the second profile including a plurality of alternating elevations and depressions, a maximum distance between two neighboring elevations being 100 μm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Further details of aspects of the present invention will be described hereafter in more detail based on exemplary embodiments and figures. In the drawings:

[0055] FIG. 1 shows an exemplary embodiment of a multilumen body; and

[0056] FIG. 2 shows a cross-section through the multilumen body of FIG. 1.

DETAILED DESCRIPTION

[0057] FIG. 1 shows a section of an insulating tube 1 for a cardiac pacemaker electrode, which comprises an outer cover tube 2 and a silicone tube 3 arranged in the outer cover tube 2. The outer cover tube 2 serves as a first tubular element, whereas the inner silicone tube 3 serves as a second tubular element. The cover tube 2 comprises a lumen in the interior thereof, in which the silicone tube 3 is accommodated. The silicone tube 3, in turn, comprises a central inner lumen 4 and three peripheral inner lumina 5. The insulating tube 1 is consequently a multilumen body.

[0058] An outer side of the silicone tube 3 is in close contact with an inner side of the cover tube 2. So as to reduce the size of the contact surface between the silicone tube 3 and the cover tube 2, the silicone tube 3 has a profile 6, which serves as a second profile, on the outer surface thereof. In the exemplary embodiment shown in FIG. 1, the inner surface of the cover tube 2, which is oriented toward the outer surface of the silicone tube 3, is not profiled, but has a smooth design.

[0059] So as to produce the insulating tube 1, the cover tube 2 and the silicone tube 3 are extruded independently of one another. Thereafter, the tubes thus produced are pushed inside one another. This kind of pushing inside one another is typically comparatively difficult since high friction results between the tubes to be pushed inside one another.

[0060] As a result of the profile 6, however, both the static friction and the sliding friction between the cover tube 2 and the silicone tube 3 are significantly reduced, so that the silicone tube 3 can be easily pushed into the cover tube 2, or the cover tube 2 can be easily pulled over the silicone tube 3.

[0061] The central inner lumen 4 of the silicone tube 3 is used to accommodate a guide wire or stylet so as to introduce the insulating tube 1 into a human body or an animal body (in particular when it was already finished to form a pacemaker electrode). The peripheral inner lumina 5 are used to accommodate a respective electrical conductor, wherein such an electrical conductor does not necessarily have to be provided in each of the inner lumina 5.

[0062] FIG. 2 shows a cross-section through the insulating tube 1 of FIG. 1, wherein like elements are denoted by like reference numerals.

[0063] The profile 6 is even more apparent in the cross-sectional illustration of FIG. 2, which in the exemplary embodiment of FIG. 2 has a corrugated design. It encompasses a plurality of alternating peaks 61, which serve as elevations, and valleys 62, which serve as depressions. A distance d between two neighboring peaks 61 of the profile 6 is 100 μm in the exemplary embodiment of FIG. 2. It must be taken into consideration in the process that FIG. 2 is not implemented to scale. Rather, the profile 6 is illustrated in enlarged form so as to be better visible.

[0064] This distance of 100 μm is not suitable for accommodating an electrical conductor within a valley 62 of the profile 6. Rather, only the peripheral inner lumina 5 are used to accommodate electrical conductors within the silicone tube 3.

Exemplary Embodiment: Reduction of Friction

[0065] First, as a comparative example, an inner silicone tube without a profiled outer surface, having an outside diameter of 2.55 mm, was used, and covered with an outer cover tube. This cover tube had an inside diameter of 2.55 mm and an outside diameter of 2.65 mm. The cover tube was made of a thermoplastic polyurethane. Both the static friction force and the sliding friction force were ascertained, which have to be overcome to pull the cover tube over the silicone tube.

[0066] Thereafter, the experiment was repeated with a silicone tube having an outer profile. The silicone tube was made of the same material as the silicone tube of the comparison experiment. Furthermore, a cover tube made of the same material and having the same dimensions as the cover tube of the comparison experiment was used.

[0067] The profiled silicone tube likewise had a maximum outside diameter of 2.55 mm, additionally having a profile that was corrugated, in the cross-sectional view, at the outer surface thereof across the entire length thereof. The distance between two neighboring peaks of this corrugated structure was 100 μm.

[0068] The static friction force to be overcome and the sliding friction force to be overcome were also ascertained in the case of the profiled silicone tube. Thereafter, the ratio of the static friction forces for the profiled silicone tube to the non-profiled silicone tube and the ratio of the sliding friction forces for the profiled silicone tube to the non-profiled silicone tube were found.

[0069] Ultimately, it was possible to ascertain that the static friction force in the case of the profiled silicone tube was 75% to 85% lower than in the case of the non-profiled silicone tube, while the sliding friction force was approximately 65% to 75% lower than in the case of the non-profiled silicone tube. Measurements conducted on the profiled silicone tube having a maximum outside diameter of 2.55 mm and a corrugated profile, in the cross-sectional view, on the outer surface thereof, with a distance between two neighboring peaks of this corrugated structure of 32 μm, yielded comparable results.

Exemplary Embodiment: Reduction of the Contact Surface

[0070] So as to ascertain how much the contact surface between the outer cover tube and the inner silicone tube can be reduced by profiling of the silicone tube, the insulating tubes used in the preceding exemplary embodiment were further examined. In the case of the non-profiled silicone tube, the silicone tube rested completely against the cover tube. The contact surface between the cover tube and the non-profiled silicone tube thus corresponded to the inner cross-sectional circumference of the cover tube or the outer cross-sectional circumference of the silicone tube. A diameter of 2.55 mm thus resulted in a contact line of approximately 8 mm.

[0071] The profiled silicone tube included 80 peaks and interposed valleys, which were located 100 μm away from one another. On average, each peak was in contact with the inner surface of the cover tube across a width of 23 μm. This adds up to a contact line of 1.84 mm, which corresponds to a reduction in the contact line of approximately 77%.

[0072] When the cover tube is pulled equally far over the non-profiled silicone tube and the profiled silicone tube, likewise a reduction in the contact surface between the cover tube and the silicone tube of 77% results.

[0073] Another profiled silicone tube, having a comparable diameter, included valleys that were located 32 μm away from one another. Likewise, a reduction in the contact line of approximately 77% was measured in the case of this tube.

[0074] It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof. Additionally, the disclosure of a range of values is a disclosure of every numerical value within that range, including the end points.