Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

1. TITLE OF THE INVENTION:
STEERABLE MEDICAL DEVICE AND METHOD OF MAKING THEREOF

2. APPLICANT:
Meril Life Sciences Pvt. Ltd., an Indian company of the Survey No. 135/139 Bilakhia House, Muktanand Marg, Chala, Vapi-Gujarat 396191, India.

The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
[1] The present disclosure relates to a catheter. More particularly, the present disclosure relates to a steerable medical device.
BACKGROUND OF INVENTION
[2] A catheter is a thin, flexible, tube-like medical device. It is used in various medical procedures to perform tasks such as draining fluids from the body, delivering fluids into the body, measuring pressure within specific organs or blood vessels, and accessing areas inside the body. Catheters come in various sizes, materials, and designs to suit their intended purposes. They are commonly used in healthcare settings, including hospitals and clinics, and often employed in procedures such as urinary catheters, central venous catheters, cardiac catheters, intravenous catheters and so on.
[3] Delivery of a catheter is a minimally invasive procedure. It involves careful insertion and positioning of the catheter within a body cavity, blood vessel, or duct to perform a range of medical procedures. The medical practitioners steer the catheter through intricate anatomical structures and tortuous pathways to reach the desired location. Once the catheter is in the desired location, various medical procedures can be performed, including draining fluids, administering medications or treatments, measuring or imaging studies, delivering nutrition, diagnosing any potential abnormalities or conditions, delivering stents, etc.
[4] However, successfully navigating through intricate anatomical structures and tortuous pathways to reach the desired location is challenging. Conventionally, steerable catheters typically consist of a set of pull wires coupled to a pull ring. These components are usually constructed from different materials and fabricated individually before being assembled together. The challenge arises from instances where conventional devices may collapse and components detach from their joining points during the insertion. Detachment of components of the catheter shaft can cause device malfunction or failure, leading to ineffective treatment, prolonged procedure time, or need for further interventions. Additionally, the detached components can remain in the patient’s body and migrate from one place to another like heart or brain etc. If the detached components penetrate surrounding tissue or organs, it can cause tissue damage or perforation, leading to bleeding, organ damage or other complications. It can potentially cause harm or injury in the internal organs or blood vessels leading to serious complications like brain stroke. In order to remove the detached components, another procedure or interventions would be employed. This can result in increased healthcare costs, prolonged hospital stays, and patient discomfort, making it difficult to ensure reliability during critical interventions. Further, these detached components can create invasion points for bacteria or other microorganisms, leading to infection which can result in systemic sepsis or localized abscess formation.
[5] Hence, there is a need of catheter shaft that overcomes the problems associated with the conventional devices.
SUMMARY OF INVENTION
[6] Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are mere examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
[7] The present disclosure relates to a steerable device having a proximal end and a distal end. In an embodiment, the steerable device includes a shaft, a steering mechanism and an integrated pull element. The shaft has a proximal end, a distal end and a tip. The shaft includes an inner layer and an outer layer. The steering mechanism is coupled to the proximal end of the shaft. The integrated pull element is disposed between the inner layer and the outer layer of the shaft and includes a pull ring and at least one pull wire. The pull ring is disposed towards the distal end of the shaft, and the at least one pull wire extends from the pull ring. The at least one pull wire is disposed, at least partially, within the shaft. A proximal end of the at least one pull wire is operatively coupled to the steering mechanism. The pull ring and the at least one pull wire are fabricated from a single tubing, thereby eliminating the need for bonding the pull ring to the at least one pull wire and lowering the risk of breakage at the point where they are bonded.
[8] A method of fabricating an integrated pull element is disclosed. In an embodiment, the method includes providing a tubing. The method further includes machining the tubing as per a digital design of the integrated pull element. The integrated pull element includes at least one pull wire coupled to a pull ring. The method further includes finalizing the machined integrated pull element.
[9] A method of fabricating a steerable device is disclosed. In an embodiment, the method includes wrapping a film of an inner layer of a shaft on a mandrel. The method further includes disposing an integrated pull element on an exterior surface of the first layer. The integrated pull element includes at least one pull wire coupled to a pull ring. The pull ring and the at least one pull wire are made from a single tubing. The method further includes wrapping an outer layer along the length of the inner layer, wherein the outer layer of the shaft includes different sections of different durometers. The method further includes subjecting the assembly to a lamination process to yield the shaft.
BRIEF DESCRIPTION OF DRAWINGS
[10] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the apportioned drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentality disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[11] Fig. 1 depicts a device 10, according to an embodiment of the present disclosure.
[12] Fig. 2a depicts a cross-sectional front view of the shaft 12, according to an embodiment of the present disclosure.
[13] Fig. 2b depicts an exploded perspective view of the shaft 12, according to an embodiment of the present disclosure.
[14] Fig. 2c depicts a cross-sectional transverse view of the shaft 12, according to an embodiment of present disclosure.
[15] Fig. 3a depicts an integrated pull element 55 including a pull ring 50 and one pull wire 60, according to an embodiment of the present disclosure.
[16] Fig. 3b depicts the integrated pull element 55 including the pull ring 50 and two pull wires 60, according to an embodiment of the present disclosure.
[17] Fig. 3c depicts the integrated pull element 55 including the pull ring 50 and three pull wires 60, according to an embodiment of the present disclosure.
[18] Fig. 3d depicts the integrated pull element 55 including the pull ring 50 and four pull wires 60, according to an embodiment of the present disclosure.
[19] Fig. 3e depicts the integrated pull element 55 including a C-shaped pull ring 50 and one pull wire 60, according to an embodiment of the present disclosure.
[20] Fig. 4 depicts the integrated pull element 55 including a plurality of marker cavities 52 on the pull ring 50, according to an embodiment of the present disclosure.
[21] Figs. 5a – 5h depict a variety of patterns for arrangement of the plurality of marker cavities 52 on the pull ring 50, according to an embodiment of the present disclosure.
[22] Fig. 6 depicts a flowchart of a process 700 of fabricating the integrated pull element 55 having the pull ring 50 and the at least one pull wire 60, according to an embodiment of the present disclosure.
[23] Fig. 7 depicts an exemplary assembly 800 for machining a single tubing 108, according to an embodiment of the present disclosure.
[24] Fig. 8a depicts an exemplary assembly 900a for subjecting the at least one pull wire 60 to the grinding process, according to an embodiment of the present disclosure.
[25] Fig. 8b depicts an exemplary assembly 900b for subjecting the pull ring 50 to the grinding process, according to an embodiment of the present disclosure.
[26] Fig. 9 depicts an exemplary assembly 1000 for subjecting the integrated pull element 55 to sand blasting process, according to an embodiment of the present disclosure.
[27] Fig. 10a depicts an assembly 1100a for subjecting the integrated pull element 55 to the electro-polishing process, according to an embodiment of the present disclosure.
[28] Fig. 10b depicts an assembly 1100b for subjecting the integrated pull element 55 to the electro-polishing process, according to another embodiment of the present disclosure.
[29] Fig. 11 depicts a flowchart of a process 1200 for fabricating the device 10 having the integrated pull element 55, according to an embodiment of the present disclosure.
[30] Fig. 12a depicts the integrated pull element 55 having one or more radiopaque markers 52a coupled to respective marker cavities 52, according to an embodiment of the present disclosure.
[31] Fig. 12b depicts coupling of integrated pull element 55 with an inner layer 26 of the device 10, according to an embodiment of the present disclosure.
[32] Fig. 13a depicts coupling of a middle layer 24 and the inner layer 26 of the shaft 12, according to an embodiment of the present disclosure.
[33] Fig. 13b depicts coupling of an outer layer 22 with the middle layer 24 of the shaft 12, according to an embodiment of the present disclosure.
[34] Fig. 14 depicts subjecting the shaft 12 to a heating process, according to an embodiment of the present disclosure.
[35] Fig. 15 illustrates a flowchart of a process 1800 for shaping a distal portion 12b1 of the shaft 12, according to an embodiment of the present disclosure.
[36] Figs. 16a – 16b depict a mold 132 for shaping the distal portion 12b1 of the shaft 12, according to an embodiment of the present disclosure.
[37] Figs. 17a – 17b depict the distal portion 12b1 of the shaft 12 inserted into the mold 132, according to an embodiment of the present disclosure.
[38] Figs. 18a – 18b depict the mold 132 holding the distal portion 12b1 of the shaft 12 placed inside an oven 136, according to an embodiment of the present disclosure.
[39] Fig. 19 depicts a pre-steered distal portion 12b1 of the shaft 12, according to an embodiment of the present disclosure.
[40] Fig. 20 depicts an assembled view of the device 10, according to an embodiment of the present disclosure.
[41] Fig. 21 depicts an exploded view of a handle 200, according to an embodiment of the present disclosure
[42] Fig. 22 depicts an exploded view of a steering mechanism, according to an embodiment of the present disclosure.
[43] Figs. 23a – 23b depict an exploded view of a sliding member 208, according to an embodiment of the present disclosure.
[44] Fig. 24 depicts a flowchart of a method 2000 of operating the device 10, according to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[45] Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms "include" and "comprise", as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "coupled with" and "associated therewith", as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like. Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.
[46] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
[47] Although the operations of exemplary embodiments of the disclosed method may be described in a particular, sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular, sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment, and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses.
[48] Furthermore, the described includes, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific includes or advantages of a particular embodiment. In other instances, additional includes and advantages may be recognized in certain embodiments that may not be present in all embodiments. These includes and advantages of the embodiments will become more fully apparent from the following description and apportioned claims, or may be learned by the practice of embodiments as set forth hereinafter.
[49] This current disclosure pertains to a steerable device (or referred to as a device). The device includes a shaft that is introduced in the body during a catheterization process such as cardiac catheterization, urinary catheterization, central venous catheterization, intravenous catheterization and more. The device may be a catheter, an introducer sheath, etc.
[50] In an embodiment, the device is provided with an integrated pull element including a pull ring and at least one pull wire. In an embodiment, the integrated pull element is fabricated from a single tubing of a suitable material using a machining (e.g., laser cutting). The integrated pull element eliminates the need for bonding the pull ring to the at least one pull wire, thereby reducing the risk of breakage at the point where they are bonded. As a result, it enhances the device’s resistance to kinking or collapsing during the medical procedures, and reduces the susceptibility of detachment of the at least one pull wire from the pull ring as is observed with the conventional devices. This, in turn, improves its durability, enabling it to withstand intricate medical procedures without breaking or detaching. This enhanced durability ensures their reliability during critical interventions. Further, it overcomes the challenges faced by the conventional devices, such as, device malfunction, ineffective treatment, prolonged procedure time, and tissue damage, organ damage, injury infection, etc. caused by detached components remaining in the patient’s body. Thus, the integrated pull element improves the performance of the device and the patient outcome. Additionally, the pull ring of the device may be equipped with radiopaque markers or components that are visible under medical imaging, helping healthcare providers in accurately positioning the shaft within the body. It enhances safety, precision, and ease of maneuvering within intricate anatomical structures, facilitating accurate and targeted interventions.
[51] Further, in an embodiment, the distal portion of the shaft is pre-steered at a pre-determined angle. Due to this, less effort is required for steering the shaft. Additionally, it ensures the device aligns quickly with the natural contours of the body, thereby minimizing trauma to surrounding tissues and organs during the insertion and advancement, providing comfort to the patient.
[52] The shaft is flexible that allows easy navigation through the body’s intricate pathways, such as blood vessels or urinary tracts etc. This flexibility minimizes trauma to tissues and ensures smooth advancement.
[53] Now referring to the figures, Fig. 1 illustrates a device 10 according to an embodiment. The device 10 may be a catheter, an introducer sheath, etc. In an embodiment, the device 10 is an introducer sheath. The device 10 may include a plurality of components operationally coupled to each other. The device 10 has a proximal end 10a and a distal end 10b, and includes a shaft 12 extending from the proximal end 10a. The shaft 12 has a proximal end 12a, a distal end 12b and a distal tip 12c (hereinafter tip 12c). In an exemplary embodiment, a distal portion 12b1 of the shaft 12 is curved. The tip 12c of the shaft 12 could be steered in a desired direction with the help of a steering mechanism provided at the proximal end 10a of the device 10. Any suitable steering mechanism may be used without deviating from the scope of the present disclosure. The steering mechanism may be disposed within a handle (not shown in Fig. 1) of the device 10 provided at the proximal end 10a. An exemplary implementation of the steering mechanism is explained later.
[54] In an embodiment, the tip 12c is pre-steered at a pre-defined angle on a left or a right side. The pre-defined angle may range between 160° and 240°. In an exemplary embodiment, the tip 12c is pre-steered at 210° on the right side. This enables the shaft 12 to navigate through intricate anatomical structures of the patient by maintaining its conformity with the natural contours of the body. An exemplary process to fabricate the shaft 12 having a pre-steered tip 12c is explained later. In another embodiment, the tip 12c may not be pre-steered, i.e., the tip 12c may be substantially straight.
[55] The shaft 12 has a hollow, tubular structure. The shaft 12 extends from the proximal end 12a to the distal end 12b, thereby defining a length. The length of the shaft 12 may be between 500 mm and 1600 mm. In an embodiment, the length of the shaft 12 is 720 mm. Referring to Fig. 2a, the shaft 12 may include two or more layers and a lumen 40 disposed from the proximal end 12a to the distal end 12b. In the depicted embodiment, the distal portion 12b1 of the shaft 12 is not curved. The lumen 40 serves as a hollow channel or tube that runs through the entire length of the shaft 12. The lumen 40 may serve various functions such as, without limitation, delivery of various fluids or medications, drainage of various fluids, flushing out or cleaning specific areas, passage of instruments or components (for example, guidewires, catheters, dilators, stents, balloons), etc.
[56] In an exemplary embodiment, as shown in Fig. 2a, the layers include an outer layer 22, a middle layer 24, and an inner layer 26. The coupling of these layers with each other has been explained in the later parts. Though the present disclosure is detailed using a shaft having three layers, the teachings of the present invention extend to shafts having two or more layers including at least the inner layer 26 and the outer layer 22. In an embodiment, the outer layer 22 may include properties corresponding to the middle layer 24 as described below.
[57] The inner layer 26 serves as a barrier between the material or substances passing through the lumen 40 and the other layers of the shaft 12. This may help in maintaining the sterility of the shaft’s 12 interior. Along with that, the inner layer 26 provides a smooth, low-frictional surface that allows for the passage of materials or substances through the lumen 40 of the shaft 12. In an embodiment, the inner layer 26 may be lined with biocompatible materials, such as, without limitation, PTFE, polyimides, high density polyethylene (HDPE), Fluorinated ethylene propylene (FEP) etc. In an exemplary embodiment, the inner layer 26 is lined with PTFE. This allows components, such as, a dilator, a catheter, a stent, a balloon, etc., to pass through the shaft 12.
[58] The outer layer 22 of the shaft 12 provides a protective barrier for various inner components of the shaft 12. The outer layer 22 may be made of PEBAX, nylon, silicone, teflon, or any other suitable biocompatible polymer. The outer layer 22 may have a different durometer in different sections of the shaft 12 for a desired operation of the device 10. For example, a distal portion of the outer layer 22 may be made of a material having a lower durometer to provide flexibility and softness to steer the shaft 12, whereas a proximal portion of the outer layer 22 may be made of a material having a higher durometer to have enough rigidity for support and pushability while advancing the shaft 12. The material used to make the proximal section may be the same or different than the material used to make the distal section. In an embodiment, the distal section of the outer layer 22 may be made of PEBAX having durometer ranging between 20D and 40D and the proximal section of the outer layer 22 may be made of PEBAX or nylon having the durometer ranging between 50D and 75D.
[59] The middle layer 24 of the shaft 12 is provided between outer layer 22 and inner layer 26. The middle layer 24 provides structural integrity and stability to the shaft 12. In an embodiment, the middle layer 24 may include a reinforcing structure to provide support and kink resistance to the shaft 12 during the medical procedure. In an embodiment, the reinforcing structure may be made from wires or hypotubes of a suitable biocompatible material such as, without limitation, stainless steel, nitinol, polyethylene etc. arranged in a suitable pattern, for example, a mesh, a braiding, a coil, zig-zag patterns, horizontal and vertical slits, spiral pattern, etc. or combinations thereof.
[60] Further, the device 10 includes a pull ring 50 and at least one pull wire 60 (as shown in Fig. 2b). In an embodiment, the pull ring 50 and the at least one pull wire 60 form an integral structure, hereinafter referred to as an integrated pull element 55. The integrated pull element 55 reduces the risk of detachment or disconnection of the at least one pull wire 60 from the pull ring 50 during the medical procedure. This ensures that the device 10 remains functional and reliable throughout the procedure, and improves the patient outcome.
[61] The at least one pull wire 60 is disposed from the proximal end 12a towards the distal end 12b of the shaft 12 and has a distal end 60b and a proximal end 60a (as shown in Fig. 2c). The at least one pull wire 60 is at least partially disposed within the shaft 12. The at least one pull wire 60 may have a uniform or a non-uniform thickness throughout its length. In the depicted embodiment, the at least one pull wire 60 has a uniform thickness. The thickness of the at least one pull wire 60 may range between 0.08 mm and 0.3 mm. The length of the at least one pull wire 60 may range between 80 mm and 1600 mm. In an exemplary embodiment, the at least one pull wire 60 has a thickness of 0.12 mm and a length of 800 mm. The at least one pull wire 60 may have a suitable shape, such as, cylindrical, cuboidal, etc. In an embodiment, the at least one pull wire 60 is a flat wire having a rectangular cross-section, which reduces the profile of the shaft 12.
[62] The pull ring 50 is disposed towards the distal end 12b of the shaft 12. The pull ring 50 may be ring-shaped. The inner diameter of the pull ring 50 may range between 0.5 mm and 8 mm. The outer diameter of the pull ring 50 may range between 0.7 mm and 8.2 mm. In an embodiment, the inner diameter and the outer diameter of the pull ring 50 are 3.3 mm and 3.5 mm, respectively. The length of the pull ring 50 may range between 1 mm and 6 mm. In an embodiment, the length of the pull ring 50 is 4 mm.
[63] As shown in Figs 2a – 2c, the integrated pull element 55 is provided between the inner layer 26 and the middle layer 24 of the shaft. The pull ring 50 is disposed between the inner layer 26 and the outer layer 22. The at least one pull wire 60 extends from a proximal end of the pull ring 50 towards the proximal end 12a of the shaft 12 and is disposed between the inner layer 26 and the middle layer 24.
[64] In an embodiment, the proximal end 60a of the at least one pull wire 60 emerges out towards the proximal end 12a of shaft 12 at a corresponding exit port (as shown in Fig. 2c) and is operatively coupled to a steering mechanism (an embodiment of the steering mechanism is shown in Figs. 20-21). When the steering mechanism is used to pull the at least one pull wire 60 in a desired direction, it induces tension in the at least one pull wire 60, which, in turn, results in the pull ring 50 being pulled, thereby causing the tip 12c to steer in an intended direction.
[65] In an embodiment, the pull ring 50 and the at least one pull wire 60 may be made of a suitable biocompatible material, such as, without limitation, stainless steel, nitinol, elgiloy etc. In an exemplary embodiment, the pull ring 50 and the at least one pull wire 60 are made of stainless steel.
[66] Figs. 3a- 3e, 4 and 5a – 5h illustrate various embodiments of the integrated pull element 55. For example, Fig. 3a illustrates the integrated pull element 55 having the pull ring 50 and one pull wire 60. One pull wire 60 allows the user to steer the shaft in one direction. Fig. 3b illustrates the integrated pull element 55 having the pull ring 50 and two pull wires 60. Two pull wires 60 allow the user to steer the shaft in two directions. Fig. 3c illustrates the integrated pull element 55 having the pull ring 50 and three pull wires 60. Three pull wires 60 allow the user to steer the shaft in three directions. Fig. 3d illustrates the integrated pull element 55 having the pull ring 50 and four pull wires 60. Four pull wires 60 allow the user to steer the shaft in four directions. Though Figs. 3b – 3d show multiple pull wire 60 spaced evenly along the circumference of the pull ring 50, in an embodiment, the multiple pull wires 60 may be spaced unevenly. Further, Figs. 3a – 3d show the pull ring 50 having a ring shape, though other variations are possible. For example, Fig. 3e illustrates the integrated pull element 55 having the pull ring 50 of a C-shape and one pull wire 60.
[67] According to an embodiment of the present disclosure, the pull ring 50 may designed to be radiopaque. Radiopacity of the pull ring 50 provides information about the orientation and alignment of the tip 12c. Further, it helps the healthcare professionals to track the position of the shaft 12 while advancing the shaft 12 through the patient’s body while performing the medical procedures. In an embodiment, the pull ring 50 may be coated with a radiopaque polymer, for example, barium sulphate, bismuth etc. In another embodiment, the pull ring 50 may be coated with a radiopaque metal, for example, tungsten, gold, platinum, iridium, etc. In an embodiment, the pull ring 50 may be coated with a radiopaque material using techniques such as dip coating, spray coating etc. In an embodiment, the pull ring 50 may be coated with nanoparticles of a radiopaque materials.
[68] In another embodiment, one or more radiopaque markers 52a may be coupled to the pull ring 50 to provide radiopacity. The pull ring 50 may be provided with one or more marker cavities 52. The one or more marker cavities 52 may be slots, holes, grooves, etc. The one or more marker cavities 52 may have any shape such as, circular, oval, square, rectangular, triangular, pentagonal, hexagonal, heptagonal, octagonal, decagonal, star, drop, etc. In an embodiment, the one or more radiopaque markers 52a having a corresponding shape are coupled with the one or more marker cavities 52 by using techniques, such as, without limitation, welding, riveting, crimping, clamping, hooking, welding, brazing, etc. In an exemplary embodiment, the one or more radiopaque markers 52a are coupled with the one or more marker cavities 52 by using welding technique (explained later). The one or more marker cavities 52 may be arranged in a pre-defined pattern, such as, horizontal straight lines, vertical straight lines, waves, zig-zag, mesh, etc. In an embodiment, the one or more marker cavities 52 may be circular holes as shown in Fig. 4. In an embodiment, the one or more marker cavities 52 may be slots provided on an outer surface of the pull ring 50. Figs. 5a – 5g illustrate various embodiments of the one or more marker cavities 52 as slots having different shapes and patterns. In an embodiment, the one or more marker cavities 52 may be holes extending outward from a circumference of the pull ring 50 in a distal direction as shown in Fig. 5h.
[69] Fig. 6 illustrates a flowchart of a process 700 of fabricating the integrated pull element 55, according to an embodiment of the present disclosure. At step 702, the tubing 108 is provided, for which a suitable material is chosen. The tubing 108 may be made of a suitable biocompatible material such as, without limitation, stainless steel, nitinol, elgiloy, etc. In an exemplary embodiment, the tubing 108 made of stainless steel is selected. Dimensions (such as length, inner diameter, outer diameter, thickness, etc.) of the tubing 108 are chosen based upon desired dimensions of various components of the shaft 12. For example, an inner diameter of the tubing 108 is greater than or equal to an outer diameter of the inner layer 26. Further, the length of the tubing 108 may be at least equal to the desired length of the integrated pull element 55.
[70] At step 704, a digital design 101 of the integrated pull element 55 is prepared using a Computer Aided Design (CAD) software. Any known CAD software such as, AutoCAD, Adobe Illustrator, Solidworks, Onshape, Inkspace, Sketchup, etc., may be used to prepare the digital design 101. A variety of data and information may be input into the CAD software to prepare the digital design 101. Examples of the data and information input into the CAD software include, without limitation, material and dimensions of the tubing 108, dimensions of the integrated pull element 55 (for example, length, outer diameter, inner diameter, thickness of the pull ring 50, length, thickness of the at least one pull wire 60), the number of the at least one pull wire 60 and their placement along the circumference of the pull ring 50, information (shapes, sizes, pattern, positions, etc.) about the one or more marker cavities 52, etc. The CAD software generates digital models that represent the physical components. These models include precise measurements, dimensions and specifications. The CAD software can stimulate and analyze the behavior of designs under various conditions. This helps in identifying potential issues and allows for optimization before physical fabrication. The user may select an optimal design (e.g., the digital design 101) in the CAD software. In an embodiment, Computer Aided Manufacturing (CAM) software is integrated with the CAD software or vice versa. The CAM software interprets the digital design 101 to generate machine toolpath data used during the fabrication process. The machine toolpath data may guide subsequent processes such as, cutting, shaping process, etc.
[71] At step 706, the digital design 101 is loaded into software for controlling a laser cutting machine 104. The software for controlling the laser cutting machine 104 may be installed on a computer 102 communicatively coupled with the laser cutting machine 104 using a suitable interface. The control software ensures that the fabrication process is accurate and matches the design configured by the operator. One or more process configurations may be set by the operator into the control software as per requirements. The one or more process configurations include, without limitation, power of a laser beam, frequency of the laser beam, cutting speed of the laser beam, focus of the laser beam, pressure of an assist gas, lubricant pressure. The one or more process configurations may be decided based on the material and design requirements. In an embodiment, a gas, such as, without limitation, argon, oxygen, etc. may be used as the assist gas. In an embodiment, the frequency of the laser beam ranges from 8 kHz to 12 kHz. In an embodiment, the duration of the laser beam pulse ranges between 0.010 ms and 0.030 ms. In an embodiment, the output power of the laser beam ranges between 60W and 100W. In an exemplary implementation, the frequency, pulse duration and output power of the laser beam are 10 kHz, 0.018 ms and 80 W, respectively. In an embodiment, argon is used as the assist gas having a pressure ranging between 14 Bar and 16 Bar. In an exemplary implementation, argon is used at a pressure 15.5 Bar.
[72] At step 708, the tubing 108 is machined to maintain the dimensional accuracy of the layers during the fabrication process. The tubing 108 may be machined using various methods, such as, without limitation to, casting, computer numerical control machining (CNC machining), laser cutting, extrusion process, etc. In an embodiment, the tubing 108 is machined using the laser cutting machine 104. An exemplary assembly 800 for machining the tubing 108 is shown in Fig. 7. The tubing 108 is passed through a bush 111 into a laser cutting chamber 110. One end of the tubing 108 is held by a chuck 114 placed inside the laser cutting chamber 110. The other end of the tubing 108 is held by a tube holder 112 as shown in Fig. 7. A gas pipeline extends from a gas cylinder having the assist gas and is attached to the laser cutting machine 104. An appropriate pressure is set. The laser cutting machine 104 is then switched ON. The laser cutting machine 104 follows the toolpath instructions precisely and cuts the tubing 108 using a laser beam 106. The laser beam 106 is a high energy beam that vaporizes or melts the material of the tubing 108 at the designated point. The laser cutting machine 104 is controlled by the control software loaded on the computer 102 as per the digital design 101 and the set parameters. Thus, the laser cutting machine 104 at this step removes undesired material of the tubing 108 as per the digital design 101 of the integrated pull element 55. Once the machining is complete, the integrated pull element 55 having the pull ring 50 and the at least one pull wire 60 as an integrated structure is formed. In the depicted embodiment, the integrated pull element 55 has one pull wire 60 and the pull ring 50 having two marker cavities 52 in the form of circular holes.
[73] The integrated pull element 55 is finalized after the machining step at 708. In an embodiment, the finalizing step comprises one or more steps, which are explained below.
[74] At step 710, the integrated pull element 55 is subjected to a grinding process. After the machining process, burrs and deformities may form over the surface of the integrated pull element 55. The grinding process is employed to remove those burrs and deformities and achieve the desired surface finish and dimensional accuracy.
[75] In an embodiment, the at least one pull wire 60 of the integrated pull element 55 is subjected to grinding process. An exemplary grinding assembly 900a for grinding the at least one pull wire 60 is shown in Fig. 8a. In an embodiment, the grinding assembly 900a includes a grinding machine 116 for grinding the at least one pull wire 60. The grinding machine 116 includes a grinding wheel 116a and a support wheel 116b. The grinding wheel 116a is a rotating tool responsible for removing material from the surface of the at least one pull wire 60 of the integrated pull element 55. The grinding wheel 116a grinds away excess material and irregularities to create a smoother and more precise flat surface. In an embodiment, the operative parameters may be fed into a computer controlling the grinding machine 116. In an embodiment, the speed of the grinding wheel 116a can be between 4000 rpm and 8000 rpm. The integrated pull element 55 may be moved back-and-forth at a desired rate (hereinafter referred to as a feed rate) so that entire length of the at least one pull wire 60 can be subjected to the grinding process. In an embodiment, the integrated pull element 55 may be moved manually or mechanically. In an exemplary embodiment, the integrated pull element 55 is moved mechanically, involving a carriage coupled to a lead screw (not shown) that holds the integrated pull element 55 from one end and moves it back-and-forth. In an embodiment, the feed rate is between 0.08 m/s and 0.2 m/s. In an exemplary embodiment, the speed of the grinding wheel 116a and the feed rate are 5500 rpm and 0.1 m/s, respectively. These operative parameters determine the rate of material removal and the quality of the surface finish of the at least one pull wire 60 of the integrated pull element 55. The support wheel 116b serves as a support and guide for the surface of the at least one pull wire 60 of the integrated pull element 55. The surface of the at least one pull wire 60 passes between the grinding wheel 116a and the support wheel 116b. The support wheel 116b facilitates the continuous feeding of the at least one pull wire 60 through the grinding zone, enabling precision grinding. The support wheel 116b exerts controlled pressure against the at least one pull wire 60 to prevent deflection or vibration during grinding. Additionally, the support wheel 116b rotates at a specified speed, synchronized with the grinding wheel's 116a rotation to regulate the uniform speed of grinding of the at least one pull wire 60 of the integrated pull element 55. Further, a clover gel may be applied to a mandrel of the grinding machine 116 used to hold the integrated pull element 55. The clover gel is then washed using a sterile cloth to remove any residual burrs on the surface of the at least one pull wire 60.
[76] In an embodiment, the pull ring 50 of the integrated pull element 55 is subjected to grinding process. An exemplary grinding assembly 900b for grinding the pull ring 50 is shown in Fig. 8b. In an embodiment, the grinding assembly 900b includes a grinder machine 118. The grinder machine 118 includes a grinding file 118a and a motorized chuck 118b coupled to one end of the grinding file 118a. The grinding file 118a has a grinding surface 118d on outside and is held such that the grinding surface 118d contacts an inner surface of the pull ring 50 during the grinding process. The integrated pull element 55 may be moved back-and-forth as described earlier, at a desired feed rate so that the inner surface of the pull ring 50 can be subjected to the grinding process. When the motorized chuck 118b rotates, the grinding file 118a coupled to the motorized chuck 118b also rotates. The grinding surface 118d of the grinding file 118a rotates against the inner surface of the pull ring 50, removing excess material and irregularities. The motorized chuck 118b is coupled to a column coupled to a base 118c of the grinder machine 118. In an embodiment, multiple grinding files 118a of different grades may be used based upon requirements so that desired quality of surface polish and burr removal is achieved. Further, a clover gel may be applied to a mandrel of the grinder machine 118 mandrel used to hold the integrated pull element 55. The clover gel is then washed using a sterile cloth to remove any residual burr on the surface of the pull ring 50.
[77] At step 712, the integrated pull element 55 is subjected to a honing process. The honing process may be performed using a honing machine. The honing process provides smoother surface finish with precise and consistent dimensions of the integrated pull element 55.
[78] At step 714, the integrated pull element 55 is subjected to a sandblasting process to remove any microscopic burrs remaining on the surface of the integrated pull element 55 after subjecting the integrated pull element 55 to the grinding and honing processes. An exemplary assembly 1000 for the sandblasting process is shown in Fig. 9. In an embodiment, during the sandblasting process, a media 120 of an abrasive material, such as, but not limited to, sand, glass beads, aluminum oxide, steel shot, etc. are propelled at high velocity on the surface of the integrated pull element 55 using compressed air or pressured gas. The integrated pull element 55 may be held or clamped to a mandrel (not shown).
[79] The abrasive material may be chosen based on the desired surface finish and the material of the integrated pull element 55. In an exemplary embodiment, particles of aluminum oxide are chosen as the media 120. The media 120 is loaded into a sandblasting equipment (not shown). The sandblasting equipment includes a sandblasting chamber 122a and a nozzle 122b that blasts the media 120 out of the sandblasting chamber 122a and a dust collection system (not shown). The pressure of the compressed air (or gas) and the nozzle 122b is adjusted so as to control the velocity and direction of the media 120. In an embodiment, the air pressure is adjusted within the range of 3-5 bar. In an embodiment, the flow pressure of the media 120 may be in the range of 35 - 45 psi. The frequency with which the abrasive particles are propelled onto the integrated pull element 55 is controlled so as to achieve the desired smoothness on the surfaces of the integrated pull element 55. In an embodiment, the frequency varies between 55-65 Hz. The stream of the media 120 is directed onto surface of the integrated pull element 55 using the nozzle 122b. In an exemplary embodiment, the air pressure, flow pressure of the media 120 and the frequency are 4 bar, 40 psi and 60 Hz, respectively. In order to achieve uniform results, the nozzle 122b is moved evenly and consistently across the surface of the integrated pull element 55. This results in finely smooth surface of the integrated pull element 55, that is ready for subsequent processes.
[80] At step 716, the integrated pull element 55 is subjected to an electro-polishing process. Electro-polishing is an electrochemical process that is employed to eliminate any impurities or contaminants and sharp edges remaining on the integrated pull element 55 after the sandblasting process. Exemplary electropolishing assemblies 1100a and 1100b are shown in Figs. 10a and 10b, respectively.
[81] A tank 124 containing an electrolytic bath 124a is prepared with a solution composed of an electrolyte, generally acids with high viscosity. The electrolytic bath 124a may depend upon the material used to make the integrated pull element 55. In an embodiment, when the integrated pull element 55 is made of the stainless steel, a mixture of acids, such as, but not limited to, sulfuric acid or phosphoric acid and water may be used as the electrolytic bath 124a (referring to Fig. 10a). In an embodiment, when the integrated pull element 55 is made of nitinol, a mixture of acids, such as, but not limited to, perchloric acid and acetic acid may be used as the electrolytic bath 124a (referring to Fig. 10b). The electrolytic bath 124a maintains the right concentration and ambient temperature. In an embodiment, two electrodes 126 (anode and cathode) are placed in the electrolytic bath 124a. The electrodes 126 are electrically connected to a positive and a negative terminal, respectively, of a power supply 128.
[82] In an embodiment, the integrated pull element 55 may be immersed into the electrolytic bath 124a and the power supply 128 is switched on, referring to fig. 10(a). In another embodiment, the integrated pull element 55 may be clamped using a wire (e.g., a copper wire) coupled to the power supply 128, referring to fig. 10(b). A rotor 130 may be placed beneath the tank 124 containing the electrolytic bath 124a. The rotor 130 causes constant agitation of the electrolytic bath 124a and prevents localized variations in the electrochemical reaction, thereby helping in achieving uniform electro-polishing results. The integrated pull element 55 may be kept in the electrolytic bath 124a for a pre-defined time. In an embodiment, the pre-defined time may range between 3 minutes to 4 minutes.
[83] Once the power supply 128 is switched on, electrochemical reactions lead to removal of metal ions from the surface of the integrated pull element 55. During the process, a thin layer of material is removed from the surface of the integrated pull element 55. As the electro-polishing process progresses, the surface of the integrated pull element 55 smoothens, effectively removing micro-roughness and irregularities left by the sandblasting process.
[84] One or more operating parameters of the electropolishing process may be controlled as per requirement. The one or more operating parameters may include current and voltage applied by the power supply 128, time period (i.e., the time for which the integrated pull element 55 is immersed in the electrolytic bath 124a) and the number of cycles (each cycle lasts for one time period). The pre-defined current ranges between 0.1 Amp to 6 Amp. The pre-defined voltage ranges between 0.1 V to 16V. The pre-defined time period ranges between 3 minutes to 4 minutes. The pre-defined number of cycles ranging between 2 and 5 may be performed. In an exemplary embodiment, the pre-defined current, the pre-defined voltage, the pre-defined time period and the pre-defined number of cycles are 0.9 Amp, 9 V, 1.5 min and 3, respectively.
[85] Fig. 11 illustrates a flowchart of a process 1200 for fabricating the device 10, according to an embodiment of the present disclosure.
[86] At step 1202, suitable materials for the shaft 12 are chosen. In an embodiment, the materials may be chosen on the basis of one or more factors, such as, but not limited to, shrinkage allowance of the materials, heat shrink sleeve to be used, flexibility and stiffness of material as per requirement etc. A suitable mandrel is chosen depending upon the required inner diameter of the inner layer 26. The mandrel is a cylindrical tool intended to serve as a supportive element during the fabrication process.
[87] At step 1204, the one or more radiopaque markers 52a are coupled to the pull ring 50. The techniques used include without limitation riveting, crimping, clamping, hooking, welding, brazing, etc. In an embodiment, each of the one or more radiopaque markers 52a is fit into respective marker cavities 52 and is coupled with the pull ring 50 of the integrated pull element 55 using welding (shown in Fig. 12a). In an embodiment, when the pull ring 50 is coated with radiopaque materials, this step may not be performed.
[88] At step 1206, a film of a material chosen for the inner layer 26 is wrapped around the mandrel. The film of the material for the inner layer 26 is wrapped so as to have a desired thickness for the inner layer 26. In an exemplary embodiment, a film of PTFE is wrapped around the mandrel.
[89] At step 1208, the integrated pull element 55 is disposed on the exterior surface of the inner layer 26 (shown in Fig. 12b). The pull ring 50 of the integrated pull element 55 is coupled to the inner layer 26 towards a distal end of the inner layer 26 using welding, adhesive, etc. Further, the at least one pull wire 60 is coated with a layer 26a of a material same as that of the inner layer 26.
[90] At step 1210, the middle layer 24 having the reinforcing structure is formed over at least a portion of the inner layer 26 (as shown in Fig. 13a). The reinforcing structure is formed using, for example, wires or hypotubes of a suitable biocompatible material (e.g., stainless steel, polyethylene, nitinol, etc.) arranged in a pre-defined pattern (e.g., a mesh, a braiding, a coil, zig-zag patterns, horizontal and vertical slits, spiral pattern, etc. or combinations thereof). In an exemplary embodiment, the middle layer 24 includes braids and/or coils formed using wires made of a suitable material (e.g., stainless steel, polyethylene or nitinol). The wires may be flat or round wires. A braiding/coiling process may be applied to form the middle layer 24. The middle layer 24 is formed such that the middle layer 24 covers the inner layer 26 from the distal end 60b of the at least one pull wire 60 to the proximal end of the inner layer 26, and the at least one pull wire 60. A proximal portion of the at least one pull wire 60 may be pulled out from the middle layer 24 at a region of an exit port of the shaft 12 as per requirements.
[91] At step 1212, a film of a suitable biocompatible material (e.g., PEBAX, nylon, silicone, teflon) chosen for outer layer 22 is wrapped (as shown in Fig. 13b) along the length of the inner layer 26. In an exemplary embodiment, a film of PEBAX is wrapped. The film of the material may be wrapped along the entire length of the shaft 12 so as to achieve a desired thickness of the outer layer 22.
[92] At step 1214, the shaft 12 is subjected to a lamination process. In the lamination process, a heat shrink sleeve is formed and heat is applied using a lamination apparatus 1400 (as shown in Fig. 14). In another embodiment, the heat may be applied to the shaft 12 at a pre-defined temperature. As the temperature rises the film of the material of the outer layer 22 melts and flows through the reinforcing structure of the middle layer 24 and bonds with the inner layer 26. Thereafter, the shaft 12 is cooled down.
[93] Upon cooling, the heat shrink sleeve is cut and peeled off from the outer layer 22 at step 1214 and the mandrel is withdrawn from the inner layer 26. At step 1216, the shaft 12 is assembled with a handle having a steering mechanism. The steering mechanism enables a medical practitioner to steer the tip 12c to a desired angle during a medical procedure. This process results in the creation of the device 10.
[94] In an embodiment, the distal portion 12b1 (including the tip 12c) of the shaft 12 may be shaped such that the tip 12c is pre-steered at a pre-defined angle on a desired side during the fabrication of the device 10. The pre-defined angle may be between 160° and 240°. In an embodiment, the tip 12c may be shaped at an angle 210° on the right side. Fig. 15 illustrates a flowchart of a process 1800 for shaping the distal portion 12b1 of the shaft 12, according to an embodiment of the present disclosure. The process 1800 may be performed after step 1216 of the process 1200 described earlier.
[95] At step 1802, a mold 132 is prepared. One embodiment of the mold 132 is illustrated in Figs. 16a – 16b. The mold 132 may be made of materials such as, without limitation, stainless steel, aluminum casting, acrylonitrile butadiene styrene (ABS), etc. In an exemplary embodiment, the mold 132 is made of acrylonitrile butadiene styrene (ABS). The mold 132 may be cuboidal, cylindrical, tubular etc. In an exemplary embodiment, the mold 132 is cuboidal. According to an exemplary embodiment, the mold 132 includes an upper part 132a and a lower part 132b. Each of the mold parts 132a and 132b includes a respective cavity 133a and 133b (collectively, referred to as the cavity 133) having a pre-defined shape. The pre-defined shape corresponds to a desired shape of the distal portion 12b1of the shaft 12. An exemplary embodiment of the pre-defined shape is illustrated in Fig. 16b. The dimensions of the cavity 133 correspond to the dimensions of the distal portion 12b1 of the shaft 12.
[96] The mold 132 may be provided with a locking mechanism, such as, but not limited to, press-fit locking, screw locking, chain locking, etc. This ensures the upper and lower mold parts fit together, maintaining the desired alignment of the cavity 133. In an exemplary embodiment, a press-fit locking mechanism is used. The upper part 132a and lower part 132b of the mold 132 may be provided with press-fit lock elements (not shown), which when mate form the press-fit locks 134 (illustrated in Fig. 16b) to secure the upper part 132a and the lower part 132b together.
[97] At step 1804, the distal portion 12b1 of the shaft 12 is disposed within the cavity 133 of the mold 132 (as shown in Figs. 17a – 17b). The upper part 132a of the mold 132 is fastened to the lower part 132b of the mold 132 using the locks 134 so as to prevent any movement of a portion of the device 10 inside the mold 132. Alternate ways of fastening include screwing or chain wounding. The distal portion 12b1of the shaft 12 to be shaped may have a length between 8 mm and 140 mm. In an exemplary embodiment, the length of the distal portion 12b1 of the shaft 12 to be shaped is 50 mm.
[98] At step 1806, the mold 132 holding the distal portion 12b1 of shaft 12 is heated at a pre-defined temperature for a pre-defined time period. In an embodiment, the predefined temperature ranges from 150°-180°C. In an embodiment, the pre-defined time period ranges from 50-70 minutes. In an exemplary embodiment, the mold 132 holding the distal portion 12b1of the shaft 12 is subjected to a temperature of 160°C and for 60 minutes. In an embodiment, the mold 132 may be placed on an oven tray 135 (shown in Fig. 18a). The oven tray 135 is then inserted into an oven 136 (as shown in Fig. 18b). The oven 136 is heated at the pre-defined temperature. Subjecting the distal portion 12b1 of the shaft 12 to the pre-defined temperature for the pre-defined time period helps the distal portion 12b1 of the shaft 12 to acquire the desired shape defined by the cavity 133 of the mold 132. After the pre-defined time period passes, the mold 132 is taken out from the oven 136 and quenched. After the quenching process, the shaft 12 is recovered from the mold 132.
[99] At step 1808, a hydrophilic coating 28 is applied on the shaft 12 (as shown in Fig. 19). The hydrophilic coating 28 may be applied partially or completely on the shaft 12, as per requirement. In an embodiment, the hydrophilic coating 28 is applied partially on the shaft 12. The hydrophilic coating 28 may be of a material, such as, without limitation, polyvinylpyrrolidone (PVP), polyurethanes, polyacrylic acid (PAA), polyethylene oxide (PEO), polysaccharide materials, etc. In an embodiment, the hydrophilic coating 28 is of polyvinylpyrrolidone (PVP). The hydrophilic coating 28 is applied to smoothen an outer surface of the shaft 12.
[100] As explained earlier, the tip 12c of the shaft 12 can be steered in the desired direction with the help of any suitable steering mechanism that may be provided at the proximal end 10a of the device 10. One embodiment of the steering mechanism for the shaft 12 having the distal portion 12b1 (and hence, the tip 12c) pre-steered to a first steering direction is illustrated with the help of Figs. 20 – 23. The first steering direction corresponds to the tip 12c being pre-steered at the pre-defined angle on a first side. In the depicted embodiment, the first side is the right side. It should be appreciated that any other suitable steering mechanism for the shaft 12 with or without the pre-steered tip 12c can be used without deviating from the scope of the present disclosure.
[101] An assembled view of the device 10 is shown in Fig. 20, according to an embodiment. The device 10 includes a handle 200 provided at the proximal end 10a. The handle 200 is coupled to the proximal end 12a of the shaft 12. The device 10 includes a hemostasis hub 220 having a hemostasis valve (not shown). A three-way stopcock 220a is coupled to the hemostasis hub 220 using a tubing 220b. The hemostasis hub 220 is provided proximal to the handle 200 and is coupled to the proximal end 12a of the shaft 12.
[102] The handle 200 includes an upper case 202a (shown in Fig. 20) and a lower case 202b (shown in Fig. 21). The upper case 202a and the lower case 202b may be provided with any suitable locking mechanism known in the art. In an exemplary embodiment, the upper case 202a and the lower case 202b are provided with press-fit elements (not shown), which when pressed secure the upper case 202a and the lower case 202b together.
[103] A plurality of steering indicators 203 are provided on the upper case 202a of the handle 200, configured to provide a visual cue for the user to steer the tip 12c of the shaft 12 during the interventional procedures. Each of the plurality of steering indicators 203 indicates a corresponding direction of the tip 12c of the shaft 12. In an exemplary embodiment, the plurality of steering indicators 203 includes a right indicator 203a, a neutral indicator 203b and a left indicator 203c, as shown in Fig. 20. In an embodiment, the neutral indicator 203b indicates a neutral direction of the tip 12c, the right indicator 203a indicates the first steering direction of the tip 12c and the left indicator 203c indicates a second steering direction of the tip 12c by the pre-defined angle on a second side different than the first side. In the depicted embodiment, the second side is the left side.
[104] The steering mechanism is disposed within the handle 200. The proximal end 60a of the at least one pull wire 60 (in the depicted embodiment, a single pull wire 60) is coupled to the steering mechanism. The steering mechanism is configured to steer the tip 12c to at least the neutral direction and the second steering direction. In an embodiment, the steering mechanism includes a slider button 204 and a sliding member 208 operatively coupled to the slider button 204. The slider button 204 is configured to move within a slot 202c provided in the upper case 202a of the handle 200, as shown in Fig. 20 to at least a neutral position and a second position. In an embodiment, the slider button 204 is movable to a first position, the neutral position and the second position. The first position, the neutral position and the second position of the slider button 204 correspond to the first steering direction, the neutral direction and the second steering direction, respectively, of the tip 12c. The sliding member 208 slides in a channel 216 provided in the lower case 202b of the handle 200 as shown in Fig. 21.
[105] The proximal end 60a of the at least one pull wire 60 is operatively coupled to the steering mechanism using any suitable technique such as riveting technique, knotting, crimping, male female locking technique, clamping, hooking, welding, brazing, etc. In the depicted embodiment, the proximal end 60a of the at least one pull wire 60 is crimped to the sliding member 208 as explained below. The sliding member 208 includes a proximal plate 210a, a distal plate 210b and a pull wire gripper 212 provided on a base, as shown in Figs. 23a – 23b. The pull wire gripper 212 includes a column 212a provided between a proximal portion 212b and a distal portion 212c. The proximal portion 212b and the distal portion 212c have curved ends towards a proximal and a distal end of the sliding member 208, respectively. The column 212a is provided with at least one slot. In an exemplary embodiment, the at least one slot of the column 212a includes a first slot B and a second slot C (as shown in Fig. 23b). The at least one pull wire 60 is received by a slot A provided on the distal plate 210b (as shown in Fig. 23a and 23b), which then passes through the first slot B, wraps around curved ends of the proximal portion 212b, passes through the second slot C provided on the column 212a and then wraps around curved ends of the distal portion 212c, as shown in Figs. 23a and 23b. Each of the distal plate 210b and proximal plate 210a has a surface 210c (as shown in Fig. 23a), configured to remain in contact with the channel 216 provided on the lower case 202b of the handle 200 (as shown in Fig. 21).
[106] The sliding member 208 may be coupled to the slider button 204 by any means that is known in the art. In an exemplary embodiment, the slider button 204 includes a support 206 having a first leg 206b and a second leg 206a, as shown in Fig. 22. The first leg 206b and the second leg 206a include a first protrusion 206b1 and a second protrusion 206a1, respectively. The first protrusion 206b1 and the second protrusion 206a1 are received by a first aperture 210b1 on the distal plate 210b and a second aperture 210a1 on the proximal plate 210a, respectively.
[107] To steer the tip 12c of the shaft 12 in a desired direction, the slider button 204 is moved within the slot 202c and is aligned with a desired steering indicator 203 of the plurality of steering indicators 203, for example, the neutral indicator 203b and the left indicator 203c, corresponding to the neutral position and the second position, respectively, of the slider button 204. In response to the movement of the slider button 204, the sliding member 208 slides in the channel 216 provided on the lower case 202b. This induces tension in the at least one pull wire 60 and as a result, the tip 12c is steered to the desired direction. For example, in response to the slider button 204 being moved to one of the neutral position or the second position, the sliding member 208 is configured to pull the at least one pull wire 60, thereby steering the tip 12c to the neural direction or the second steering direction, respectively.
[108] Fig. 24 depicts a flowchart 2000 of a method of operating the device 10, according to an embodiment of the present disclosure.
[109] At step 2002, the user slides the slider button 204 to align with the neutral indicator 203b provided on the handle 200. This induces a tension in the at least one pull wire 60, and as a result, the tip 12c of the shaft 12 is steered to the neutral direction from the pre-steered state (i.e., the first steering direction). A dilator (not shown) is inserted inside the shaft 12 at the tip 12c.
[110] At step 2004, the shaft 12 is inserted in a patient’s body and advanced through the vasculature to a target location.
[111] At step 2006, the dilator is removed once the tip 12c reaches the target location. The user grips and moves the slider button 204 and aligns it with a first desired indicator provided on the handle 200 to cause steering of the tip 10c towards a first desired direction. For example, the user moves the slider button 204 and aligns it with the right indicator 203a (i.e., the first desired indicator) to turn the tip 12c by the pre-defined angle (e.g., 180 degrees or more) in the right direction (i.e., the first steering direction). This releases the induced tension in the at least one pull wire 60, as a result the tip 12c of shaft 12 is brought back to its pre-steered state (i.e., the first steering direction).
[112] At step 2008, the user grips and moves the slider button 204 and aligns it with a second desired indicator provided on the handle 200 to cause steering of the tip 12c towards a second desired direction. For example, the user moves the slider button 204 and aligns it with the left indicator 203c (i.e., the second desired indicator) to turn the tip 12c by the pre-defined angle in the left direction (i.e., the second steering position). This induces tension in the at least one pull wire 60, as a result the tip 12c of the shaft 12 is steered to the second steering direction.
[113] Though the steering mechanism and operating the shaft 12 have been explained herein with respect to the pre-steered tip 12c, it should be appreciated that any other steering mechanism for the shaft 12 with or without the pre-steered tip 12c can be used and the shaft 12 can be operated accordingly and the same is covered within the scope of the present disclosure.
[114] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used. , Claims:WE CLAIM
1. A steerable device (10) having a proximal end (10a) and a distal end (10b), comprising:
a. a shaft (12) having a proximal end (12a), a distal end (12b) and a tip (12c), the shaft (12) including an inner layer (26) and an outer layer (22);
b. a steering mechanism coupled to the proximal end (12a) of the shaft (12); and
c. an integrated pull element (55) disposed between the inner layer (26) and the outer layer (22), comprising:
i. a pull ring (50) disposed towards the distal end (12b) of the shaft (12) and;
ii. at least one pull wire (60) extending from the pull ring (50) and disposed at least partially within the shaft (12), a proximal end (60a) of the at least one pull wire (60) operatively coupled to the steering mechanism;
wherein the pull ring (50) and the pull wire (60) are fabricated from a single tubing (108) thereby eliminating the need for bonding the pull ring (50) to the pull wire (60) and reducing the risk of breakage at the point where they are bonded.
2. The steerable device (10) as claimed in claim 1, wherein the inner layer (26) is lined with a biocompatible material.
3. The steerable device (10) as claimed in claim 2, wherein the biocompatible material comprises polytetrafluoroethylene (PTFE), polyimides, high density polyethylene (HDPE), Fluorinated ethylene propylene (FEP).
4. The steerable device (10) as claimed in claim 1, wherein the outer layer (22) is made of a biocompatible polymer.
5. The steerable device (10) as claimed in claim 4, wherein the biocompatible polymer comprises PEBAX, nylon, silicone, teflon.
6. The steerable device (10) as claimed in claim 1, wherein the outer layer (22) includes different sections of different durometers.
7. The steerable device (10) as claimed in claim 1, wherein the shaft (12) includes a middle layer (24), sandwiched between the inner layer (26) and the outer layer (22), having a reinforcing structure disposed between the outer layer (22) and the inner layer (26).
8. The steerable device (10) as claimed in claim 7, wherein the reinforcing structure is made from wires or hypotubes arranged in a pre-defined pattern.
9. The steerable device (10) as claimed in claim 7, wherein the reinforcing structure is made of a biocompatible material.
10. The steerable device (10) as claimed in claim 9, wherein the biocompatible material comprises stainless steel, polyethylene, nitinol.
11. The steerable device (10) as claimed in claim 1, wherein the pull ring (50) is radiopaque to track the position of the shaft (12) while in use.
12. The steerable device (10) as claimed in claim 1, wherein a distal portion (12b1) of the shaft (12) is pre-steered at a first steering direction, wherein the first steering direction corresponds to a pre-defined angle on a first side.
13. The steerable device (10) as claimed in claim 12, wherein the steering mechanism, disposed within a handle (200) having an upper case (202a) and a lower case (202b), is configured to steer the tip (12c) to at least a neutral direction and a second steering direction on a second side different than the first side, the steering mechanism comprising:
a. a slider button (204) configured to move within a slot (202c) provided in the upper case (202a) to at least a neutral position and a second position corresponding to the neutral direction and the second steering direction, respectively;
b. a sliding member (208) coupled to the proximal end (60a) of the at least one pull wire (60), the sliding member (208) configured to slide in a channel (216) provided in the lower case (202b) in response to the movement of the slider button (204);
wherein, in response to the slider button (204) being moved to one of the neutral position or the second position, the sliding member (208) is configured to pull the at least one pull wire (60), thereby steering the tip (10c) to the neutral direction or the second steering direction, respectively.
14. The steerable device (10) as claimed in claim 13, wherein the upper case (202a) comprises a plurality of steering indicators (203) indicating the first steering direction, the neutral direction and the second steering direction.
15. The steerable device (10) as claimed in claim 1, wherein the single tubing (108) is made of a biocompatible material.
16. The steerable device (10) as claimed in claim 15, the biocompatible material comprises stainless steel, nitinol, elgiloy.
17. A method of fabricating an integrated pull element (55) comprising:
a. providing a tubing (108);
b. machining the tubing (108) as per a digital design (101) of the integrated pull element (55) having at least one pull wire (60) coupled to a pull ring (50); and
c. finalizing the machined integrated pull element (55).
18. The method of fabrication as claimed in claim 17, wherein the step of finalizing includes one or more of:
a. grinding the machined integrated pull element (55);
b. horning the grinded integrated pull element (55);
c. sandblasting the integrated pull element (55); and
d. electropolishing the sandblasted integrated pull element (55).
19. A method of fabricating a steerable device (10), comprising:
a. wrapping a film of an inner layer (26) of a shaft (12) on a mandrel;
b. disposing an integrated pull element (55) on an exterior surface of the inner layer (26), the integrated pull element (55) including at least one pull wire (60) coupled to a pull ring (50) wherein the pull ring (50) and the at least one pull wire (60) are made from a single tubing (108);
c. wrapping an outer layer (22) along the length of the inner layer (26), wherein the outer layer (22) of the shaft (12) includes different sections of different durometers; and
d. subjecting the assembly of step (c) to a lamination process to yield the shaft (12).
20. The method of fabrication as claimed in claim 19, wherein the method comprises placing a distal portion (12b1) of the shaft (12) in a mold (132) and heating at a pre-defined temperature for a pre-defined time period for pre-steering the distal portion at a pre-defined angle towards a desired side.
21. The method of fabrication as claimed in claim 19, wherein the method comprises forming a middle layer (24) having a reinforcing structure over at least a portion of the inner layer (26).
22. The method of fabrication as claimed in claim 19, wherein the method comprises applying a hydrophilic coating (28) on the outer layer (22) to smoothen an outer surface of the shaft (12).
23. The method of fabrication as claimed in claim 19, wherein the method comprises assembling the shaft (12) with a handle having a steering mechanism.