Variable diameter tube for use in a vasal inserter for performing hemodynamics researches and related operations and method for making said tube

Abstract

A variable diameter tube for use in a vessel inserter for performing hemodynamics researches and related operations comprises two coupled different-characteristic materials which are coupled to one another to provide a single stretchable tube assembly.

Claims

1. A variable diameter tube, comprising: a first material layer comprising a C-shaped cross-section, the first material layer comprising polyether ether ketone and only one longitudinal cut; and a second material layer comprising polyurethane, wherein the second material layer is coupled to the first material layer along an outside surface of the first material layer such that the second material layer is disposed around the first material layer, wherein the second material layer is not coupled to lateral surfaces of the longitudinal cut, the variable diameter tube configured to transition between a rest condition, wherein the variable diameter tube has a rest diameter, and an enlarged diameter condition, wherein the variable diameter tube has an enlarged diameter; wherein the second material layer is flexible such that a displacement between the lateral surfaces of the longitudinal cut increases as an object having a diameter that is greater than the rest diameter of the variable diameter tube is inserted into the variable diameter tube, wherein the second material layer is more resilient than the first material layer such that transition of the variable diameter tube from the rest condition to the enlarged diameter condition increases the displacement between the lateral surfaces of the longitudinal cut and stretches at least a portion of the second material layer; and wherein the second material layer defines a folded flap, the folded flap extending inward between the lateral sides of the longitudinal cut when the variable diameter tube is in the rest condition.

2. The variable diameter tube of claim 1, wherein the first material layer further comprises carbon fiber reinforcing components.

3. The variable diameter tube of claim 1, wherein the second material layer has a shape memory in that it returns to the rest diameter when unconstrained.

4. The variable diameter tube of claim 3, wherein the rest diameter is about 3.2 mm.

5. The variable diameter tube of claim 1, further comprising a lubricating material disposed on the first material layer.

6. The variable diameter tube of claim 1, wherein the first material layer is glued to the second material layer.

7. The variable diameter tube of claim 1, wherein the diameter of the variable diameter tube is variable by at least one millimeter between the rest condition and the enlarged diameter condition.

8. A variable diameter tube, comprising: a first material layer comprising a C-shaped cross-section, the first material layer comprising polyether ether ketone and only one longitudinal cut; and a second material layer comprising polyurethane, wherein the second material layer is coupled to the first material layer along an outside surface of the first material layer, wherein the second material layer is not coupled to lateral surfaces of the longitudinal cut, the variable diameter tube configured to transition between a rest condition and an enlarged diameter condition; wherein the second material is flexible such that a displacement between the lateral surfaces of the longitudinal cut increases as an object having a diameter that is greater than a rest diameter of the variable diameter tube is inserted into the variable diameter tube, wherein the second material is more resilient than the first material such that when the variable diameter tube transitions from the rest condition to the enlarged diameter condition the displacement between lateral surfaces of the longitudinal cut increases and at least a portion of the second material stretches; wherein the second material is disposed around the first material; and wherein the second material defines a U-shaped folded flap that extends radially inward between the lateral surfaces of the longitudinal cut when the variable diameter tube is in the rest condition such that the displacement between the lateral surfaces of the longitudinal cut is completely occupied by a portion of the U-shaped folded flap of the second material layer.

9. The variable diameter tube of claim 8, wherein the diameter of the variable diameter tube is variable by at least one millimeter between the rest condition and the enlarged diameter condition.

10. The variable diameter tube of claim 1, wherein the folded flap is U-shaped.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment of the invention, which is illustrated, by way of an indicative, but not limitative, example in the accompanying drawings, where:

(2) FIG. 1 is an elevation view of the variable diameter tube according to the present invention, with an inserter engaged therein;

(3) FIG. 2 is an exploded view showing the variable diameter tube to be fitted to a dilator according to the invention;

(4) FIG. 3 is a partially cross-sectioned elevation view showing a procedure for inserting a dilatator or dilating device, or other devices of less diameter;

(5) FIG. 4 is a further partially cross-sectioned elevation view, similar to FIG. 3, but showing an insertion of larger diameter dilatator devices;

(6) FIG. 5 is a cross-sectional view of a stretchable or variable diameter tube according to the present invention, with a “sandwich” construction, and with an inserter engaged therein;

(7) FIG. 6 is a further cross-sectional view of a variable diameter and stretchable tube having a “bilayer” configuration, with an inserter engaged therein;

(8) FIG. 7 shows two cross-sectional views, one of which on an enlarged scale, of the variable diameter or stretchable tube according to the present invention, with said sandwich construction;

(9) FIG. 8 shows two further cross-sectional views, one of which on an enlarged scale, of the variable diameter tube according to the present invention, having the mentioned bilayer construction; and

(10) FIG. 9 shows two further cross-sections of the variable diameter tube according to the present invention, including so-called “pence” or lug arrangements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) With reference to the number references of the above mentioned figures, the variable diameter and stretchable tube according to the present invention, which has been generally indicated by the reference number 1, consists of a rigid tube element having a stretchable or adjustable diameter, which is made by coupling two materials having different characteristics, said materials being so coupled as to provide a single rigid and stretchable article of manufacture or tube assembly.

(12) In particular, the required stiffness properties are achieved by using an extruded tubular element made of PEEK, i.e. a thermoplastic polyketone polymeric material.

(13) This material has been already used in the medical field, even for forming implanting devices, and can also be used in a carbon fiber stiffened construction, even if it is per se greatly strong.

(14) The required resilient properties are achieved, on the contrary, by using another polymer, that is linear polyurethane PU.

(15) The latter can be processed by holding, extruding, dipping methods and so on.

(16) In a low hardness formulation, it is very soft and has very good resilient properties.

(17) Another material having very satisfactory resilient and strength properties, of an elastomeric nature, is the silicone material.

(18) According to a first embodiment, the variable diameter tube 1 has a “sandwich” construction.

(19) Since the two above mentioned materials are not compatible with one another, in particular PEEK being an inert material which cannot be embedded in the PU material, the variable diameter or stretchable tube according to the present invention is made by a method comprising the following method steps.

(20) The first step provides to extrude the rigid tubular element, generally indicated by the reference number 2, having a target or set inner diameter (for example 3.1 mm and 3.2 mm in outer diameter).

(21) This tubular element 2 is accordingly longitudinally cut, for example along a single directrix line 3.

(22) The thus opened tubular element 2 has a rest diameter of substantially 3.1 mm, and it can be properly stretched.

(23) The second method step provides to make by extruding, or preferably dipping, a tubular element 4 of thin thickness, starting from a resilient material, having an outer diameter of 3.1 mm.

(24) The thus made rigid tubular element 2 is accordingly fitted on the tubular soft element 4.

(25) A first step provides to extrude a rigid PEEK tubular element, 2 having a target or set inner diameter (for example an inner diameter of 3.1 mm and 3.2 mm in outer diameter).

(26) Then, in a further step is the tubular element 2 is longitudinally cut, for example along a single directrix line 3.

(27) The thus formed longitudinally cut tubular element 2 has a rest diameter of substantially 3.1 mm, and it can be properly stretched.

(28) Then, in a further step a second tubular element 4 of this thickness, is made starting from a resilient linear polyurethane material, having an outer diameter of 3.1 mm.

(29) The thus made rigid tubular element 2 is then fitted on the tubular soft element 4.

(30) A third soft tubular element 5 is then machined to an inner diameter equal to the outer diameter of the rigid tubular element 2, that is 3.2 mm.

(31) The rigid tubular element 2, in particular, is then arranged with a sandwich arrangement between the two soft materials which are then sealed or welded to one another, both at the end portions of the tube and along the cut 6 of the rigid tubular element 2.

(32) Thus, is herein achieved a three-layer tube formed by coupling the soft and rigid tubular elements, and which can be stretched along the cut 6 performed along a directrix line of the rigid tubular element.

(33) In this connection it should be pointed out that it is also possible to provide several cuts, suitable arranged with respect to one another. Additionally, in some embodiments, the rigid tubular element may comprise a C-shaped cross-section.

(34) The end tube 1 will have, in a rest condition, the starting diameter of the rigid tube.

(35) The stretching of the tube is not a permanent one.

(36) The slippery properties of the end tube can be improved by using suitable lubricating or coating materials, as those which are conventionally used in the medical field.

(37) According to a further embodiment of the invention, the variable diameter or stretchable tube 1 according to the present has a bilayer construction, as schematically shown in FIG. 6.

(38) A removal of the inner soft tube, while leaving the rigid tubular, element 2, made of a PEEK materials, as a first layer, and an outer tubular element 7, made of a PEEK material, as an outer layer, would provide the advantage that it would not be necessary to use outer lubricating materials, since, as known, PEEK has a very low coefficient of friction.

(39) The two above layers are coupled to one another by specifically designed gluing materials or by any other desired technical methods.

(40) Accordingly, the above disclosed variable diameter tube 1 is adapted to resiliently modify its diameter, thereby it can be stretched to a larger diameter.

(41) In this connection it should be pointed out that the soft material elements, shown in the drawings by the reference numbers 4, 5, 7, could have an inner diameter larger than the above discussed minimum diameter.

(42) In such an arrangement, the stiffener element, shown in the drawings by the reference number 2, as joined to the corresponding soft elements, will provide a variable diameter or stretchable tube 1 having a “pence” or lug-flap of soft material, which can be directed either toward the inside or the outside of the tube 1.

(43) The presence of such a material excess would be useful for providing the tube 1 with an improved stretching capability, since the element 4+5 or 7 can be generally expanded to an expanding or stretching degree larger than a standard arrangement or, the expanding or stretching being the same, it will have a less tension and, accordingly, a less breaking risk.

(44) In particular, the tube 1 can comprise a portion including the above mentioned “pence” or excess material part, for example near the valve, and a standard part, for example up to the tip of the inserter.

(45) The tube diameter, in particular, is modified by the material being inserted or engaged in the inserter device: for example, as a catheter 8 having a diameter of 4 mm is herein inserted, the stretchable tube will modify its diameter from 3 mm to 4 mm.

(46) The enlarger diameter position, in particular, will correspond to a yielding limit of the soft tube.

(47) The receptive capability limit of the inserter will depend on the valve arranged at the inlet of said inserter, the resilient or elastic properties of its material and the layer geometrical arrangement.

(48) The middle positions will vary from a round configuration to an oval configuration, which is hindered by the material engaged in the inserter.

(49) The rest position will be that of less diameter, defined by the multilayer tube geometry.

(50) The tip of the tube is a tapering tip, and accordingly it will be atraumatic.

(51) In particular, as the subject variable diameter tube is engaged in a vessel, and without any catheters therein, it will be recovered to the above diameter.

(52) In some conditions, it would be desirable to provide an inserter device designed for having a diameter larger than that its rest diameter.

(53) In such a case, it is provided to use a second rigid tube adapted to hold in a pervious and rigid condition the stretchable tube.

(54) To that end it is possible to use a PEEK tube, of a thin thickness, extruded to a desired diameter, to be arranged within the stretchable tube. Said tube, in particular, will be engaged in the inserter through the dilator and then it will be left in said inserter.

(55) It has been found that the invention fully achieves the intended aim and objects.

(56) In fact, the invention provides a rigid tube that is having rigid properties with respect to the inserter body, which is adapted to adjust its diameter, starting from a minimum value to the diameter of the device to be inserted.

(57) Moreover, and this represents the main feature of the present invention, the subject tube is adapted to recover its starting diameter.

(58) Thus, the use of the variable diameter inserter will greatly improve the surgical procedure in which an inserter is used, while providing the following advantages: a great reduction of the material required for performing the procedure; a great reduction of the operational times; a great reduction of bleeding due to replacement operations; a great reduction of risks associated with a relocating of an inserter; a great reduction of the vessel traumas due to several puncturing operations; a great improving of the puncture place closure; an easy adjusting of the inserter to a lot of dimensions of the device to be inserted.

(59) In practicing the invention, the used materials, as well as the contingent size and shapes, can be any, depending on requirements.