Variable stiffness multi-lumen tube

Abstract

A medical device includes a shaft. The shaft includes an integral tube defining a plurality of lumens. The integrated pipe is composed of at least one of PTFE and ePTFE. The density of at least one of the PTFE and the ePTFE varies along the length of the unitary tube.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. 119 to U.S. Provisional Application No. 63 / 332,321, filed on April 19, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0002] The present disclosure generally relates to medical devices, systems, and related methods having multi-lumen tubing of polytetrafluoroethylene (PTFE) and / or expanded polytetrafluoroethylene (ePTFE) wherein regions of the tubing have different stiffness, density, and / or other properties. Background Art

[0003] Medical devices (e.g., catheters, endoscopes, sheaths, tubes, etc.) used during endoscopic or other procedures require a set of properties that allow the device to function as intended. For example, during a procedure (such as an endoscopy, colonoscopy, and / or endoscopic retrograde cholangiopancreatography ("ERCP")), an operator may insert a medical device into a patient and guide the medical device through tortuous anatomical structures to position the device at a target site deep in the body. Accessing the target site may require articulation or movement of a distal portion of the device, as well as bending of a more proximal portion of the device, to effectively navigate to the target site and guide the distal end at the site. Therefore, the medical device may require portions with different properties (e.g., different flexibility / stiffness). Summary of the invention

[0004] A medical device may include a shaft (or "shaft"). The shaft may include an integral tube defining a plurality of lumens, the integral tube being composed of at least one of PTFE and ePTFE, and wherein the density of at least one of the PTFE and ePTFE varies along the length of the integral tube. The density may vary within the cross section of the integral tube. In an alternative embodiment, the density of the radially inner portion of the integral tube may be different from the density of the radially outer portion of the integral tube. The integral tube may include an articulated joint. At least two regions separated by a circumference around the articulated joint may have a density less than that of other regions around the circumference. The at least two regions may be separated by approximately 180 degrees around the circumference. In an alternative embodiment, the integral tube includes an articulated joint, and the integral tube also includes a portion proximal to the articulated joint, wherein the density of the articulated joint is less than that of the proximal portion. In some embodiments, the device may also include one of a braid or a coil surrounding the outermost surface of the integral tube. One of the braid or coil may be heated to a temperature greater than or equal to 250 degrees Celsius. At least one of the thickness, pitch and material of the wire of one of the braid and the coil can vary along the length of the one of the braid and the coil. The one-piece tube can also include at least one mandrel extending through at least one of the multiple lumens. The at least one mandrel can be at a temperature greater than or equal to 250 degrees Celsius. In an alternative embodiment, the one-piece tube can also include multiple mandrels extending through more than one lumen of the multiple lumens. The first mandrel of the multiple mandrels can be at a first temperature, and the second mandrel of the multiple mandrels can be at a second temperature different from the first temperature. The density of the proximal portion of the one-piece tube can be different from the density of the distal portion of the one-piece tube. The medical device can be an endoscope, and the shaft can be connected to a handle at the proximal end of the shaft, and the multiple lumens include a working channel and a lumen for articulating the wire.

[0005] A method of producing a tube may include stretching a heated, integral starting tube of at least one of PTFE and ePTFE to produce an intermediate tube having a density less than that of the integral starting tube, wherein the starting tube defines a plurality of lumens; and linearly retracting only a first portion of the length of the intermediate tube while heating the intermediate tube to produce a final tube, wherein the first portion has a greater density than a second portion of the final tube. The method may also include inserting a mandrel through a lumen of the plurality of lumens; heating the mandrel to greater than or equal to 250 degrees Celsius; and removing the mandrel. Tension may be applied to at least one of the starting tube, the intermediate tube, and the final tube. The linear retraction may be controlled by applying a force in the longitudinal direction of the tube.

[0006] A method of forming or producing a tube may further include: inserting at least one mandrel through at least one lumen of a multi-lumen tube comprising at least one of PTFE and ePTFE; heating the mandrel to a temperature of at least 250 degrees Celsius to cause a first region of the tube to have a higher density than a second region of the tube, the first region and the second region being in the same cross-section of the tube; and removing the at least one mandrel.

[0007] It will be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not limitations on the claimed invention. As used herein, the terms "comprises," "comprising," or any other variations thereof, are intended to encompass non-exclusive inclusions, such that a process, method, article, or device comprising a series of elements includes not only those elements, but may also include other elements that are not explicitly listed or inherent to such processes, methods, articles, or devices. The term "exemplary" means "example," not "ideal." The terms "far" or "distal" refer to the direction away from the operator / toward the treatment site, and the terms "near" or "proximal" refer to the direction toward the operator. The term "approximately" or similar terms (e.g., "substantially") include values ​​of + / - 10% of the specified value. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate examples of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0009] Figure 1 An exemplary medical device according to various aspects of the present disclosure is depicted.

[0010] Figure 2 An exemplary method of making a PTFE tube according to various aspects of the present disclosure is depicted.

[0011] Figure 3A -B depicts a straight configuration ( Figure 3A ) and curved structures ( Figure 3B ) tube.

[0012] Figure 4 An exemplary segment of a multi-lumen tubing having variable stiffness is depicted in accordance with various aspects of the present disclosure.

[0013] Figure 5A -B depicts an exemplary method of manufacturing a tube having variable stiffness according to various aspects of the present disclosure ( Figure 5A ) and an exemplary depiction of the resulting tube ( Figure 5B ).

[0014] Fig. 6A-B depicts an alternative exemplary method of manufacturing a tube having variable stiffness according to various aspects of the present disclosure ( Fig. 6A ) and an exemplary depiction of the resulting tube ( Figure 6B ).

[0015] Fig. 7A -E depicts an exemplary cross-section of a multi-lumen tube having varying density according to various aspects of the present disclosure.

[0016] Figure 8 An exemplary distal portion of a multi-lumen tubing having variable stiffness is depicted in accordance with various aspects of the present disclosure. DETAILED DESCRIPTION

[0017] Reference will now be made in detail to various aspects of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same or similar reference numerals will be used to refer to the same or similar parts throughout the accompanying drawings. The term "distal" or "distal side" refers to the portion farthest from the user when the device is introduced into a subject (e.g., a patient). In contrast, the term "proximal" or "proximal side" refers to the portion closest to the user when the device is placed into a subject.

[0018] Embodiments of the present disclosure may address one or more limitations in the art. However, the scope of the present disclosure is defined by the appended claims rather than the ability to solve a particular problem. In certain embodiments, the present invention relates to a medical device comprising at least one multi-lumen feature (e.g., a tube) having at least two portions of variable stiffness or flexibility. Although the present disclosure may refer to one of a duodenoscope or an endoscope at different points, it should be understood that, unless otherwise indicated, a duodenoscope, an endoscope, a colonoscope, a ureteroscope, a bronchoscope, a laparoscope, a sheath, a catheter, a graft, a tube, a sheath, any suitable delivery device or other medical device may be used in conjunction with various aspects of the present disclosure.

[0019] The part of the medical device that can have the rigidity different from other parts or the rest of the medical device can include any structure requiring such different rigidity.For example, the tube can include an axial part (such as a distal part) with greater flexibility than the rest of the tube or shaft. This can allow, for example, a distal articulated joint to be more flexible than the more proximal part of the tube, thereby allowing easier distal steering. In another example, one or more parts of the cross section of the tube can have a flexibility different from other parts of the cross section. This can allow the tube to be more easily bent in certain planes where the cross section is the most flexible, to achieve more effective steering of the tube. In another example, at least one lumen of a multi-lumen tube can have a wall with greater flexibility than the wall of other lumens that define the tube. This can allow at least one lumen to perform its function more effectively, such as conveying a working tool, a cable, a fluid, etc. In another example, any variable rigidity part of the tube can be used in any suitable combination with any other variable rigidity part of the tube, for example, the axial distal part has a flexibility different from the more proximal part and / or there is a variable rigidity in the cross-sectional part of the tube.

[0020] Figure 1 An exemplary medical device 10 (e.g., endoscope) in one embodiment according to the present disclosure is shown. The medical device 10 includes a proximal end 11 and a distal end 13. A handle 16 having one or more knobs 18, a lock 22, and a port 20 is located at or near the proximal end 11. A shaft 12 extends from the distal end of the handle 16 to the distal end 13 of the device 10.

[0021] The shaft 12 is a tube of sufficient length and flexibility to access sites within the body and pass through tortuous anatomical structures. The shaft 12 can be a single component having one or more lumens. Alternatively, the shaft 12 can be composed of multiple components, for example, multiple tubes having a single or multiple lumens connected together. Multiple lumens 14 can extend through the shaft 12 from the proximal end to the distal end 13. The multiple lumens 14 can include any desired number of lumens, as long as the constraints associated with the cross-sectional area and desired characteristics of the shaft 12 allow. For example, the lumens 14 may include lumens for inserting / delivering instruments, delivering fluids, applying suction, accommodating cables or wires, accommodating wires for steering (connecting the handle to the distal portion), etc. As Figure 1As shown, one or more lumens in a plurality of lumens 14 can be opened at the distal side of the shaft 12, for example, to deliver fluid or instruments to the distal side of the end of the device 10. In addition or alternatively, one or more lumens in a plurality of lumens 14 can terminate at a position proximal to the distal side of the shaft 12, or a cap 28 can be placed at the distal end of the shaft 12 to close the end of one or more lumens in a plurality of lumens 14, for example, to enclose a cable for imaging and lighting. Each of a plurality of lumens 14 can be substantially parallel to each other, so that the longitudinal axes of a plurality of lumens 14 are substantially parallel to each other and parallel to the longitudinal axis of the shaft 12. A plurality of lumens 14 can include various shapes (e.g., square, oval, circular, star-shaped, etc.) and sizes. The shaft 12 is connected to a handle 16 at the proximal end of the shaft 12, allowing one or more of the plurality of lumens 14 to be entered from one or more ports 20 through the handle 16. Additionally or alternatively, multiple lumens 14 may terminate within the handle 16 and communicate with structures within the handle and / or the umbilicus 26 for aspiration, irrigation, electronics, etc., as is known in the art.

[0022] Medical device 10 can also include an articulated portion 24 for navigating in tortuous anatomical structures and guiding the farthest end of device 10 toward a target site. Articulated portion 24 can be located at the far end 13 of shaft 12 or just located at the proximal side of the far end 13 of shaft 12. Articulated portion 24 can enable a user to bend or articulate the far end 13 in any desired direction (e.g., upward, downward, leftward and / or rightward) by means known in the art, particularly by manipulating a control wire (not shown) and knob 18 contained in the lumen 14 of shaft 12 and handle 16. Articulated portion 24 can be a part of an integral one-piece shaft 12. For example, shaft 12 can include a section of sufficient axial length with materials and flexible properties further described herein. In an alternative embodiment, articulated portion 24 can be a separate component connected to the far end of shaft 12. In either embodiment, cap 28 can be connected to the farthest end of articulated portion 24.

[0023] The entire shaft 12 and / or one or more portions of the shaft 12 (e.g., articulated joint 24) may include a tube made of polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE). PTFE and ePTFE are commonly used materials in the medical device industry due to their various biocompatibility and mechanical properties.

[0024] PTFE tube can be made using various techniques known in the art. Mainly, PTFE tube is paste or stamping extrusion. Figure 2is a flow chart of an exemplary paste extrusion process 300. In a first step 302 of the process 300, PTFE in powder form and a lubricant are mixed and then compressed at below room temperature to obtain a billet.

[0025] One or more types of PTFE in powder form can be used in the blank. For example, the blank can be composed of a single type of PTFE in powder form, or the blank can be composed of different types of PTFE in powder form. For example, the blank can be composed of two or more layers of different types of PTFE in powder form. Each of the layers can have the same depth or thickness, or the layers can have different depths or thicknesses.

[0026] In further examples, the cross-section of the blank can consist of a single type of PTFE in powder form or different types of PTFE in powder form. For example, a first portion of the cross-section of the blank can consist of a single type of PTFE in powder form, and a second portion of the cross-section of the blank can consist of a second type of PTFE in powder form. The first portion, the second portion, etc. of the cross-section can be the same size or different sizes.

[0027] For example, the cross section can be divided into two halves, three thirds, four quarters, etc. Each half, each third, each quarter, etc. can be the same size and / or shape or different sizes and / or shapes. For example, if the cross section of the blank is generally circular, the first quarter can be about 90 degrees, the second quarter can be about 90 degrees, and so on. Additionally or alternatively, each quarter can be a different angle. In this way, the cross section of the blank can be symmetrical or asymmetrical. Therefore, the resulting tube can have symmetrical or asymmetrical characteristics. For example, a tube with asymmetrical characteristics can help form a tube with one or more parts with greater sealing ability and / or greater flexibility.

[0028] In other examples, the blank can be composed of different layers and different portions of PTFE in powder form. For example, a first longitudinal length of the blank can be composed of different PTFE layers in powder form, and a second longitudinal length of the blank can be composed of different cross-sectional portions of PTFE in powder form. As will be described in further detail below, different types of PTFE in powder form can be used to help impart different properties or characteristics to the manufactured tube, such as along the longitudinal length or radial width of the manufactured tube.

[0029] Then, the blank is pressed into a mold under high pressure and extruded at room temperature or under slight heating (step 304). According to an embodiment of the present disclosure, any desired PFTE resin known in the art can be used to make the tube according to the desired properties of the device using the tube. In addition, as required, lubricants or alternative additives known in the art can be added to the resin to achieve the desired properties of the tube and the device. Similar to the PTFE in powder form discussed previously, lubricants or alternative additives can be added in different layers or different cross-sectional parts of the blank. Then, the resulting tube is dried to remove the lubricant. At this point, the tube is generally referred to as "green PTFE / ePTFE tube" (green PTFE / ePTFEtube). Then, the tube undergoes sintering and cooling processes (steps 308, 310, 312). During the sintering step 310, the tube can undergo a controlled tensioning or stretching process to minimize the stretching after extrusion. The sintering involving heating the tube allows the agglomeration of PTFE resin particles, which provides a reduction in the voids and strength inside the tube. The final product is a fully sintered PTFE tube, typically wound on a spool or cut to desired lengths (step 314).

[0030] ePTFE is a microporous version of PTFE, resulting in different mechanical properties. For example, ePTFE can be softer and more flexible than PTFE. The manufacturing or production process is similar to that of PTFE, but with some differences. Specifically, after the extrusion and drying processes described above, the PTFE tube is subjected to additional manufacturing or production processes. These additional processes include subjecting the tube to longitudinal and lateral expansion processes at specific rates and elevated temperatures, thereby producing an amorphously locked ePTFE tube.

[0031] ePTFE is used in medical applications for a variety of reasons, including as tubing. For example, ePTFE tubing is able to bend without kinking. This is due to the fibril and node microstructure of ePTFE. Figure 3A An ePTFE tube 200 with an exemplary fibril and node microstructure is shown in a straight configuration. The microstructure of tube 200 includes generally parallel-running masses of material (nodes 205) with perpendicular fibers (referred to as fibrils 210) connecting them. Pores 212 exist within the network of nodes 205 and fibrils 210. Pores 212 also include axially oriented fibrils 214. Figure 3BThe tube 200 is shown in a bent configuration. During bending, at the inner arc 215, the nodes 205 will compress the pores 212, and the fibrils 210, 214 will be compressed. Along the outer arc 220, the fibrils 210, 214 are placed under tension, and the size of the pores 212 increases. Combined, this is called shortening, which enables the tube 200 to maintain its cross-sectional shape when bent. For example, despite bending, the lumen within the tube 200 will substantially maintain its shape, making the ePTFE tube particularly suitable for use as a rod and tube in various medical applications.

[0032] As mentioned above, various medical applications require multi-lumen tubing. Figure 4 A tube 100 having multiple lumens 130 extending from a proximal end 105 to a distal end 110 is shown. The tube can have one or more discrete axial sections 115, 120, 125 of different density and flexibility. For example, section 115 can be a high-density and low-flexibility section, while sections 120, 125 have reduced density and increased flexibility, or vice versa. Alternatively, sections 115, 125 can be sections with higher density and lower flexibility relative to section 120, or vice versa. The varying density and flexibility of sections 115, 120 and 125 can be achieved by, for example, layering and / or dividing a billet (not shown) from which the tube 100 is extruded into multiple sections, as described above. Additionally or alternatively, the tube 100 can be subjected to additional processes for producing multiple sections of PTFE and ePTFE tubes of different density and flexibility, as will be discussed below. As shown, the number of axial sections is not limited to three. For example, there can be more or fewer axial sections of different densities. In addition, the number of lumens 130 is not limited to the configuration shown. There may be more or fewer lumens, and their sizes may vary. 7A to 7E Additional multi-lumen tubes according to embodiments of the present disclosure are described in more detail in .

[0033] Embodiments of the present disclosure relate to methods for producing sections of PTFE and ePTFE tubing having varying densities and flexibility. In one example, Figure 5A and 5BAs shown, the process 400 starts with a green PTFE or ePTFE tube 405 (e.g., a starting tube), such as a multi-lumen tube 405. The entire length of the multi-lumen tube 405 is stretched and amorphously locked (step 410), thereby producing a longer intermediate tube 410' with reduced density and increased flexibility along the entire intermediate tube 410'. Alternatively, in order to stretch and amorphously lock the green tube 405, the tube 405 can be locally sintered and amorphously locked at a lower temperature, or subjected to a higher or lower stretching rate. Subsequently, multiple parts (segments) can be retracted to different sintering levels. However, in an exemplary embodiment, once the tube is in a fully sintered state or heated to a melting temperature or close to a melting temperature, the tube is not further modified in this step 410.

[0034] In the next step 415, a portion of the intermediate tube 410' is heated to a high temperature, up to and including a level of complete sintering, while the remainder of the intermediate tube 410' is not heated. For example, an axial portion on the left hand side of the intermediate tube 410' may be heated to cause a portion 415' of the final tube 425 to be denser and less flexible than the remainder of the final tube 425. This densification process causes the heated portion of the intermediate tube 410' to linearly retract, i.e., the axial length of the portion 415' is shortened by the heating.

[0035] The degree of linear retraction can be controlled by applying a force (e.g., tension) to the intermediate tube 410' in the longitudinal direction of the tube during this heating step 415. This can be achieved, for example, by applying a counterweight to the intermediate tube 410'. This results in a variable stiffness tube (e.g., final tube 425) in which one portion 415' has been selectively linearly retracted (higher density and less flexibility) and another portion has been stretched and amorphously locked (less density and greater flexibility). The optimal temperature used in step 415 can vary depending on the desired properties of the component of the tube. For example, the component can be heated to a temperature of approximately 350-370 degrees Celsius for a time ranging from 5 seconds to more than 1 hour. However, the component can also be heated to a temperature of approximately 250-450 degrees Celsius for a time ranging from one second to several hours. For example, the component can be heated to a temperature greater than or equal to 250 degrees Celsius. Specifically, increasing the temperature can reduce the amount of time required to heat the component. Step 415 is similar to the standard heating or sintering step 310 ( Figure 2 ) in that the part is first partially sintered or amorphously locked at a temperature below the sintering temperature. The tube is also subjected to stretching. Multiple sections (segments) of the tube are then brought to a temperature above the previous temperature. To limit the retraction of these sections, force is applied longitudinally and heat is applied only to the areas where the density is to be increased. Radial compression can also be applied with the aid of a split interference die, where the die compresses the tube to help prevent tube recoil (recoiling).

[0036] The amount of linear retraction (of the heated portion in step 415) can be controlled in a variety of additional ways. For example, before heating in step 415, a braided or knitted silk tube can be securely placed around the outside of the intermediate tube 410'. The tube made of silk braiding or knitting has inherent compression and expansion limits based on various characteristics, including the size and material of the silk, the thickness of the silk, the pitch / density of the braid, the contact pressure of the braid to the intermediate tube 410', etc. The tube can also change along the longitudinal length on any of the aforementioned characteristics. For example, the pitch / density of the braid can be different at the proximal part and at the distal part. The linear retraction of the intermediate tube 410' can be controlled / restricted by heating the intermediate tube 410' when part or all of the intermediate tube 410' is surrounded by the braid. The braid can be applied at any step after the desired shape and drying of the component after extrusion. However, it may be best to apply the braid after local sintering or amorphous locking because there are more structures in these steps.

[0037] Similarly, a metal coil may be wrapped around the intermediate tube 410' prior to heating in step 415. The coil has inherent compression and expansion limits based on various characteristics, including the size and material of the coil, the pitch of the coil, the contact pressure of the coil against the intermediate tube 410', etc. The linear retraction of the intermediate tube 410' may be controlled / limited by heating the intermediate tube 410' while part or all of the intermediate tube 410' is surrounded by the coil. Similar to the braiding or knitting pattern, the coil may be applied at any step after extruding the desired shape and drying the part. However, it may be best to apply the coil after partially sintering or amorphously locking the part because there is more structure in these steps.

[0038] In certain embodiments, by utilizing a braid, coil, or knit pattern during step 415, localized energy around the metal braid or coil will impart localized heating and amorphous locking in adjacent areas of the ePTFE tube. This can impart a three-dimensional pattern of variable density and variable flexibility in the resulting ePTFE tube that substantially matches the braid or coil pattern. The pattern can improve the bonding ability of the component surface because the surface area is much higher relative to a smooth tube. These features can also impart radial differences that can improve the hoop strength of the tube and change the bending properties of the tube.

[0039] In an alternative method 500, as Fig. 6A and 6BAs shown, the process begins with a green PTFE or ePTFE tube 505, such as a multi-lumen tube 505. In step 510, a first axial portion of the green tube 505 can be heated to a fully sintered state, thereby increasing the density of the portion and reducing the flexibility of the portion. Thus, the intermediate tube 510' produced by step 510 includes a portion 502 having a greater density and less flexibility than the remaining portion 504 of the intermediate tube 510'. The sintered portion of the intermediate tube 510' can shrink or contract due to the sintering process.

[0040] In a subsequent step 515, a portion of the intermediate tube 510' (e.g., the entire portion 504 that was not heated in step 510) can be stretched and amorphously locked, thereby reducing the density and increasing flexibility in the portion 504. Different temperatures, times, and / or tensions can be applied to the tube to achieve different degrees of sintering. Step 515 produces a final tube 525 in which one portion 502 ( Figure 6B portion on the left-hand side) than the other portion 504' ( Figure 6B The first portion 502 and the second portion 504' may be adjacent to each other (as shown in the figure), or they may be spaced apart. Each portion 502, 504' may be sintered to a different temperature in its corresponding process step 510, 515, thereby producing a tube of variable density and flexibility. Similarly, each portion 502, 504' may be stretched under different degrees of tension, which will change the length, density and flexibility of the corresponding portion.

[0041] In an alternative manufacturing method (not shown), the entire tube can be stretched at a first temperature at a first stretch rate. Subsequently, multiple portions of the tube can be further stretched at a second temperature different from the first temperature and / or subjected to a second stretch rate different from the first stretch rate. This results in a tube with variable density and properties, similar to the resulting tube described above.

[0042] Certain challenges may arise in manufacturing or producing multi-lumen tubing with varying density and flexibility, particularly ePTFE multi-lumen tubing with desired varying density and flexibility. Large air gaps in the lumen of the tube may result in variations in heat conduction to the wall throughout the cross-section of the tube. For example, when heat is applied from outside the tube to the outer surface of the tube, the innermost wall defining the lumen may not heat to the same temperature as the outer wall due to the large air gaps of the channels within the tube. This can cause different densities and flexibilities across the cross-section of the tube, with the outermost wall having the highest density and the least flexibility, while the innermost wall has a relatively low density and a relatively high flexibility. While this may have some desirable qualities, such as a more flexible lumen for a particular function, this may result in the tube not shortening evenly when the tube is bent, such as in conjunction with a tube. Figure 3A and 3BIn order for the multi-lumen structure to maintain this symmetrical and uniform curvature, a uniform (or substantially uniform) density throughout the cross-section is desired.

[0043] Heat conduction to the interior of the multi-lumen tube can be achieved by inserting a mandrel into the lumen during the heating / sintering / amorphous locking step to impart the desired thermal conduction and achieve a cross-sectional pattern, whether uniform or non-uniform, with the desired density and flexibility.

[0044] The length of the mandrel can also create a density / flexibility difference in the longitudinal axial direction. The mandrels can be solid rods made of metal with a diameter that matches the diameter of the inner cavity into which they are inserted. When heat from the outside of the tube is used to heat the tube, the metal rod mandrel will conduct that heat to a more central area of ​​the cross-section of the tube, resulting in a more uniform cross-sectional density and flexibility. Additionally or alternatively, the mandrels can be independently heated using a heat source directly coupled to the mandrels (e.g., at the exposed end of the mandrel) to add additional temperature to the internal components of the tube. Each mandrel can be heated independently, or all mandrels can be heated together.

[0045] Heating the mandrel independently at different temperatures can also realize the desired pattern of different densities and flexibility on the cross section of multi-lumen tube. The cross-sectional density and flexibility of the tube can be controlled by inductively heating the mandrel inserted into the inner cavity of the tube. For example, the mandrel can be strategically and selectively placed in one or more inner cavities, and inductively heated to a suitable temperature to produce the region of different densities. This allows control of the density and flexibility of the tube wall adjacent to the inner cavity and around the inner cavity. In addition, the mandrel using the different metals including different metallurgical properties (including different conductances) can be used to heat the surrounding wall to a desired temperature. In some embodiments, one or more mandrels can be heated to a temperature greater than or equal to about 250 degrees Celsius.

[0046] Additionally or alternatively, applying heat to the exterior portion of a single lumen or multi-lumen tube (e.g., a flexible tube) can be accomplished by partially or completely surrounding the exterior surface of the flexible tube with a hollow tube. Depending on the desired density / flexibility differential or the properties of the flexible tube, the hollow tube surrounding the flexible tube can act as a heat sink or heat source.

[0047] For example, the hollow tube can have a cavity or lumen whose inner diameter matches or approximates the outer diameter of the flexible tube. In this way, the flexible tube can be inserted into the lumen or cavity of the lumen or cavity so that the desired length of the tube is surrounded by the hollow tube. Therefore, the hollow tube surrounding the flexible tube can impart density / flexibility differences in the longitudinal, axial and / or radial directions of the flexible tube. For example, the hollow tube can be heated to a temperature greater than or equal to 250 degrees Celsius. In an alternative embodiment, the hollow tube can be a radiator, for example, to absorb heat from the tube when the flexible tube or the mandrel inserted into the lumen of the flexible tube is heated.

[0048] In some embodiments, the hollow tube can be made of one or more metals. The materials comprising the hollow tube can be used to impart density / flexibility differences or different properties on the flexible tube. For example, a first length of hollow tube can include a first metal having a first electrical conductance, and a second length of hollow tube can include a second metal having a second electrical conductance.

[0049] Thus, in some embodiments, when the flexible tube is heated or sintered, the hollow tube can absorb heat from the flexible tube, and different portions of the hollow tube can contribute to imparting different properties to the flexible tube in a radial direction (e.g., within a cross-section of the flexible tube) and / or in a longitudinal direction (e.g., along an axial length of the flexible tube). For example, a first portion of the flexible tube within a first portion of the hollow tube can have different properties than a second portion of the flexible tube within a second portion of the hollow tube. For example, an outer portion of the flexible tube or a portion of the flexible tube closer to the hollow tube can sinter less than an inner portion of the flexible tube and, therefore, have a lower density. In some embodiments, a first portion of the flexible tube within a first portion of the hollow tube can have different properties than a second portion of the flexible tube within a second portion of the hollow tube.

[0050] In an alternative embodiment, the hollow tube can be heated to a temperature greater than or equal to 250 degrees Celsius. In this way, the hollow tube can be used to impart different properties to the flexible tube in the radial and / or longitudinal directions. For example, the portion of the flexible tube closest to the hollow tube or heat source can be more sintered and therefore have a higher density.

[0051] In other alternative embodiments, as described above, the density of the flexible tube in radial and axial directions can be further controlled by inserting at least a portion of the flexible tube into a hollow tube and inserting one or more mandrels into the inner cavity of the flexible tube. The cross-sectional density and / or flexibility of the flexible tube can be further controlled, for example, by inductively heating the mandrel inserted through the inner cavity of the flexible tube. For example, one or more mandrels can be selectively placed in one or more inner cavities of the flexible tube and inductively heated to a suitable temperature to produce a region of density variation. In this way, one or more mandrels can be used as a heat source, and thus the desired properties can be imparted to the resulting flexible tube.

[0052] The one or more mandrels can be used in combination with or in addition to the hollow tube. For example, the hollow tube surrounding the flexible tube can be used as a heat sink to absorb heat from the flexible tube and / or the mandrel. In this way, the flexible tube can be heated and / or the one or more mandrels can be heated. Alternatively, the hollow tube can be used as a heat source. In this way, the one or more mandrels can be used as a heat sink and thus can impart desired properties to the resulting flexible tube.

[0053] Fig. 7A 600A according to an embodiment prior to processing steps according to the present disclosure. Tube 600A includes various working channels or lumens 630a, 630b, 630c, and 630d, as well as four channels or lumens 630e for control wires to control up, down, left, and right steering. Figure 7B In the example shown, placing mandrels only in lumens 630b and 630c and heating these mandrels will produce higher density in areas (such as area 610a) that can receive the most heat and thus reach the highest temperature. Therefore, area 610a can have a higher density and lower flexibility than other parts of the cross-section of the resulting tube 600B. Area 610a can extend along the axial length of tube 600B.

[0054] Similarly, placing the mandrel in the lumens 630a, 630d and 630b, 630c will result in a larger area 610b of material having a higher density and greater stiffness. Thus, the area 610b can have a higher density and lower flexibility than other portions of the resulting cross-section of the tube 600C. The area 610b can extend along the axial length of the tube 600C.

[0055] As more mandrels are placed in more lumens, the area of ​​material with higher density and greater stiffness increases. For example, placing a mandrel in lumen 630e in addition to lumen 630a, 630b, 630c, 630d will also result in a higher density in a larger region 610c. Region 610c can extend along the axial length of tube 600D. Finally, placing a mandrel in each of lumens 630a-e and sufficiently heating the mandrel can result in a higher density and less flexible region 610d. Region 610d may include most, if not all, of the entire cross-section of tube 600E.

[0056] The higher density regions (610a-d) are not limited to those described. For example, the higher density regions can be controlled by placing mandrels in any combination of lumens 630a-e as desired, and can be non-concentric. For example, if the user wants the bottom portion of the tube to be denser than the top portion, the user can insert and heat the mandrels in the bottom lumens 630e and 630c. This will create a density gradient in the cross-sectional portion of the tube, with a higher density region near the bottom (at least adjacent to lumens 630e and 630c).

[0057] In addition, the relatively higher density region can be controlled by the relative thermal conductivity and magnetic induction of the mandrel (e.g., based on the mandrel material) and / or the temperature of the heated mandrel. For example, heating the mandrel to a first temperature will produce a first region of higher density, while heating the mandrel to a second, higher temperature will produce a second, larger region of higher density. The axial length of the higher density region can be controlled by the length of the mandrel.

[0058] Depending on the desired properties to be imparted to the flexible tubing, a wide variety of materials may be used for the mandrel and / or hollow tube. For example, tungsten, bronze, brass, copper, silver-plated copper, Inconel, Nitinol, various stainless steels (302, 304, 316, 420, etc.) and cladding materials may be used. In addition, different geometries of these materials may also be used.

[0059] Figure 8 The distal portion of an exemplary multi-lumen tube 800 having variable stiffness is depicted. Figure 8How to produce an articulated joint by inserting a mandrel into a selected lumen to produce a preferred bending region is shown. For example, in this embodiment, as previously mentioned, an articulated joint with bidirectional bending can be produced by placing a mandrel in lumen 830b, 830d and 830e and heating the mandrel. The process produces a pipe 800 with at least two regions 810a, 810b, and the pipe 800 has a smaller density on either side relative to the top and bottom portions (i.e., the region adjacent to the position where the mandrel is placed). These at least two regions can have a density less than the remaining circumferential portions. For example, the circumference between the two regions can have a greater density than the at least two regions. The at least two regions can be separated by about 180 degrees around the circumference of the pipe, so as to realize bidirectional bending in opposite directions, as shown in the figure. However, these regions can be separated to varying degrees to realize any desired turning direction (i.e., left and bottom, left and top, right and bottom, or right and top). The axial length of these parts can be controlled by the length of the mandrel. The regions 810a, 810b of lower density and therefore greater flexibility are adjacent to lumens 830f which house control wires which translate within those lumens 830f to cause Figure 8 810a, 810b. These bending directions are in the plane of the regions 810a, 810b having greater flexibility, thereby facilitating the bending operation. It will be appreciated that creating two regions 810a, 810b of lower density is not limited to the scope of the present disclosure. For example, more or fewer regions of reduced or increased density may be produced. The generation of regions of increased or decreased density depends on the spacing and orientation of the cavities into which the mandrels are inserted.

[0060] Although the principles of the present disclosure are described herein with reference to the illustrative examples of specific applications, it should be understood that the present disclosure is not limited thereto. Those of ordinary skill in the art and those skilled in the art who obtain the teachings provided herein will recognize that additional modifications, applications, and replacements of equivalents all fall within the scope of the examples described herein. Therefore, the present invention should not be considered to be limited by the foregoing description.

Claims

1. A medical device comprising: A shaft, wherein the shaft comprises an integral tube defining a plurality of lumens, the integral tube being comprised of at least one of PTFE and ePTFE, and wherein the density of the at least one of PTFE and ePTFE varies along the length of the integral tube.

2. The medical device of claim 1, wherein the density varies within a cross-section of the integral tube.

3. The medical device of claim 1 or 2, wherein a density of a radially inner portion of the integral tube is different from a density of a radially outer portion of the integral tube.

4. The medical device of any one of the preceding claims, wherein the integral tube comprises an articulated joint, and wherein at least two regions separated by a circumference around the articulated joint have a density less than other regions around the circumference.

5. The medical device of claim 4, wherein the at least two regions are approximately 180 degrees apart around the circumference.

6. The medical device of any one of the preceding claims, wherein the integral tube comprises an articulated joint, and the integral tube further comprises a portion proximal to the articulated joint, wherein the articulated joint has a lower density than the proximal portion.

7. The medical device of any one of the preceding claims, further comprising one of a braid or a coil surrounding an outermost surface of the integral tube.

8. The medical device of claim 7, wherein the one of the braid or the coil is at a temperature of at least 250 degrees Celsius.

9. The medical device of claim 7 or 8, wherein at least one of a pitch, material, and thickness of the wires of the one of the braid and the coil varies along the length of the one of the braid and the coil.

10. The medical device of any of the preceding claims, wherein the integral tube further comprises at least one mandrel extending through at least one lumen of the plurality of lumens.

11. The medical device of claim 10, wherein the at least one mandrel is at a temperature greater than or equal to 250 degrees Celsius.

12. The medical device of any one of claims 1-9, wherein the integral tube further comprises a plurality of mandrels extending through more than one of the plurality of lumens.

13. The medical device of claim 12, wherein a first mandrel of the plurality of mandrels is at a first temperature and a second mandrel of the plurality of mandrels is at a second temperature different from the first temperature.

14. The medical device of any one of the preceding claims, wherein the density of the proximal portion of the integral tube is different than the density of the distal portion of the integral tube.

15. A medical device as claimed in any one of the preceding claims, wherein: The medical device is an endoscope, the shaft is connected to a handle at a proximal end of the shaft, and the plurality of lumens include a working channel and a lumen for an articulation wire.

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