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:
DEVICE FOR RETRIEVING AN IMPLANT FROM BODY LUMEN
2. APPLICANT:
Meril Corporation (I) Private Limited, an Indian company of the address Survey No. 135/139, Muktanand Marg, Bilakhia House, Pardi, Vapi, Valsad-396191 Gujarat, India.

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

 
FIELD OF INVENTION
[001] The present disclosure relates to a medical device. More particularly, the present disclosure relates to a device for retrieving an implant from vascular lumen.
BACKGROUND OF INVENTION
[002] Stents are medical devices used to maintain the open structure of body lumens, such as, blood vessels, airways, or gastrointestinal passages, by minimizing blockages. They are commonly used in vascular and nonvascular procedures to treat conditions like coronary artery disease, ureteral obstructions, bile duct blockages, esophageal or tracheal strictures, and the like. Stents play a crucial role in preventing the closure of these lumens caused by strictures, external compressions, and/or internal obstructions. Similarly, an embolic coil is a permanent device implanted in a patient’s vessel to treat aneurysms, blockages, and abnormal blood flow in blood vessels. There are several challenges persist regarding the effective removal or repositioning of stents or coil post-implantation.
[003] A stent or coil often migrates over time due to increasing pressure around it or asymmetrically deployment. The coil or stent migration poses significant risks, such as, vascular injury, embolization, limb ischemia, or organ dysfunction. Migration can also lead to blockages, recurrent ischemic conditions, or other complications. Some devices are currently available to retrieve the stent/coil post-implantation. However, several challenges still exist regarding effective retrieval and/or repositioning the stents/coils post-implantation.
[004] Conventional devices/system that grasp the stent with forceps or pulling on suture threads looped around the stent, have many limitations. Examples of the limitations include difficulty in accessing the stent, high friction during stent retrieval, risk of damaging the stent or surrounding tissue, and thread breakage during the removal process. Stents designed with threads or wires for radial constriction are an attempt to address this issue by enabling a “purse-string” effect for repositioning or removal. However, these designs are often hindered by excessive friction between the thread and the stent’s support frame, making retrieval cumbersome. Furthermore, sharp edges in some stent designs may cause threads to tear during removal, leading to incomplete retrieval and/or additional complications.
[005] Another critical limitation of current devices is the risk of incomplete capture of the stent or coil during the retrieval procedure. This necessitates multiple procedures, prolonging surgical time and increasing patient risk.
[006] Thus, there is a need for a device for retrieving stents or coils that overcomes the drawbacks of the conventional systems.
SUMMARY OF INVENTION
[007] 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.
[008] The present disclosure relates to a device for retrieving an implant from a body lumen. The device includes a proximal coupling element, a distal coupling element, a plurality of gripping members and a control element. Each gripping member includes an elongated portion pivotably coupled to the proximal coupling element and the distal coupling element, and a forked portion configured to engage with an implant. The forked portion includes a plurality of prongs spaced apart from each other. The control element is coupled to the distal coupling element and is capable of receiving a first actuation input and a second actuation input. In response to the control element receiving the first actuation input, the distal coupling element is configured to move axially in a proximal direction, causing the plurality of gripping member to radially expand. Further, in response to the control element receiving the second actuation input, the distal coupling element is configured to move axially in a distal direction, causing the plurality of gripping member to radially collapse.
BRIEF DESCRIPTION OF DRAWINGS
[009] 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.
[0010] Fig. 1 depicts an exploded view of a device 100 for retrieving an implant, according to an embodiment of the present disclosure.
[0011] Fig. 2 depicts a side view of the assembled the device 100 in a closed configuration, according to an embodiment of the present disclosure.
[0012] Fig. 2a depicts an enlarged view of a gripping assembly 200 of the device 100 in the closed configuration, according to an embodiment of the present disclosure.
[0013] Fig. 3 depicts a side view of the device 100 in an open configuration, according to an embodiment of the present disclosure.
[0014] Fig. 3a depicts an enlarged view of the gripping assembly 200 of the device 100 in the open configuration, according to an embodiment of the present disclosure.
[0015] Fig. 4a depicts a perspective view of an outer shaft 300, according to an embodiment of the present disclosure.
[0016] Fig. 4b depicts a perspective view of an inner shaft 301, according to an embodiment of the present disclosure.
[0017] Fig. 5a depicts a perspective view of a handle 400, according to an embodiment of the present disclosure.
[0018] Fig. 5b depicts a perspective view of a control element 403, according to an embodiment of the present disclosure.
[0019] Fig. 6a depicts a perspective view of a gripping member 201, according to an embodiment of the present disclosure.
[0020] Figs. 6b1 and 6b2 depict various perspective views of a proximal coupling element 203, according to an embodiment of the present disclosure.
[0021] Figs. 6c1 and 6c2 depict various perspective view of a distal coupling element 207, according to an embodiment of the present disclosure.
[0022] Fig. 6d depicts a perspective view of a pin 205, according to an embodiment of the present disclosure.
[0023] Fig. 6e depicts a perspective view of a link 209, according to an embodiment of the present disclosure.
[0024] Fig. 7 depicts a flowchart of a method 500 for retrieving an implant using the device 100, according to an embodiment of the present disclosure.
[0025] Figs. 8A- 8H depicts various stages during the retrieval of the stent 20 using the device 100, according to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE DRAWINGS
[0026] 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.
[0027] 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.
[0028] 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.
[0029] Furthermore, the described features, 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 features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments. These features 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.
[0030] The present disclosure relates to a device for retrieving (or repositioning) an implant implanted in a body lumen of a patient. The device may be used in various medical situations, such as retrieving stents from coronary arteries, coils from intracranial vessels, or stents used in non-vascular applications like the biliary tract or esophagus, and so forth. The proposed device is designed to improve the retrieval process by reducing procedural time, enhancing precision, and minimizing potential damage to surrounding tissues. The device has a simplified and ergonomic design, making it easy to operate and ensures minimal friction. In an embodiment, the device uses an efficient switch-operated mechanism allowing the operator to retrieve the stent or coil in fewer steps, improving overall procedural efficiency. The device’s components are designed to operate smoothly within the body lumen. Gripping members used for gripping the implant have an angular design to reduce procedural complications. This ensures that the gripping members do not cause undue pressure or damage to the vessel walls. This minimizes complications and promotes safer retrieval procedures.
[0031] Now referring to figures, Fig. 1 depicts an exploded view of a device 100 for retrieving an implant from a body lumen, according to an embodiment of the present disclosure. The implant may include a stent, a coil, a filter, a foreign body, or the like. The stent may include a peripheral vascular stent, a carotid vascular stent, an airway stent, a coronary stent, a urinary tract stent, or the like. The stent may be a drug eluting stent. The stent may be braided, laser cut, or the like. The stent may include a plurality of struts arranged in a pre-defined pattern. The coil may include peripheral coils, embolization coils, or the like. The filter may include, for example, inferior vena cava (IVC) filter, or other implantable filters. The body lumen may include blood vessels, airways, or gastrointestinal passages and the like. The device 100 has a proximal end 100a and a distal end 100b. The device 100 includes various components that work together to retrieve or reposition the implant. The present disclosure has been explained in the context of retrieving the implant. It should be understood that the device 100 can also be used for repositioning the implant. In an embodiment, the device 100 includes a gripping assembly 200, an outer shaft 300, an inner shaft 301 and a handle 400.
[0032] The device 100 is configurable to be in an open configuration and a closed configuration. The handle 400 allows a user to switch the device 100 between the open or closed configurations as desired to retrieve the implant as explained later. Fig. 2 and Fig. 3 depict a side view of the device 100 in the closed configuration and the open configuration, respectively, according to an embodiment. In an embodiment, the device 100 engages the implant and pulls it, which facilitates in retrieving and/or repositioning the implanted device.
[0033] The gripping assembly 200 is positioned at the distal end 100b of the device 100. The gripping assembly 200 is used to grip (or hold) the implant during an implant retrieval procedure. The gripping assembly 200 is configurable to be in the open configuration and the closed configuration. Fig. 2a depicts an enlarged view of the gripping assembly 200 in the closed configuration and Fig. 3a depicts the enlarged view of the gripping assembly 200 in the open configuration, according to an embodiment. The gripping assembly 200 has a proximal end 200a and a distal end 200b. The gripping assembly 200 includes a plurality of gripping member 201, a proximal coupling element 203, a plurality of pins 205, a distal coupling element 207, and a plurality of link 209. The gripping assembly 200 is radially expandable and collapsible to facilitate engaging and holding the implant during the implant retrieval procedure. In the closed configuration, the gripping assembly 200 is in the radially collapsed state, wherein the gripping member 201 are disposed towards a central axis of the gripping assembly 200 (i.e., a longitudinal axis of the device 100) and are generally aligned longitudinally as shown in Fig. 2a. In the open configuration, the gripping assembly 200 is in the radially expanded state, wherein the gripping member 201 are radially expanded away from the central axis of the gripping assembly 200 as shown in Fig. 3a.
[0034] Fig. 4a depicts the outer shaft 300, according to an embodiment. The outer shaft 300 has a proximal end 300a and a distal end 300b. The outer shaft 300 is coupled to the gripping assembly 200 at the distal end 300b and to the handle 400 at the proximal end 300a. The outer shaft 300 has a hollow, elongated, tubular structure, and includes a lumen 300c. The lumen 300c is configured to receive the inner shaft 301. The dimensions of the outer shaft 300 may be chosen based upon procedural requirements. In an embodiment, the length of the outer shaft 300 may range between 600 mm and 1000 mm, the outer diameter of the outer shaft 300 may range between 3.33 mm (10 Fr) and 5.33 mm (16 Fr), and the inner diameter of the outer shaft 300 may range between 2.67 mm (8 Fr) and 4.67 mm (14 Fr). In an example implementation, the length, the outer diameter and the inner diameter of the outer shaft 300 are 800 mm, 4 mm (12 Fr) and 3.33 mm (10 Fr), respectively. The outer shaft 300 may be made of a biocompatible material including, without limitation, polyurethane, polyether ether ketone (PEEK), nylon, polyether block amide (Pebax), etc. In an example implementation, the outer shaft 300 is made of polyurethane.
[0035] Fig. 4b depicts a perspective view of the inner shaft 301 according to an embodiment. The inner shaft 301 has a proximal end 301a and a distal end 301b. The inner shaft 301 extends longitudinally and has an elongated body. The inner shaft 301 is disposed in the lumen 300c of the outer shaft 300. The inner shaft 301 may be have a shape, such as, without limitation, cylindrical, cuboidal, oval, etc. In an example implementation, the inner shaft 301 is cylindrical. The inner shaft 301 may have a solid or hollow core for at least a partial length of the inner shaft 301. In an embodiment, the inner shaft 301 has a solid core for the entire length of the inner shaft 301. The inner shaft 301 is coupled to the control element 403. In an embodiment, the inner shaft 301 includes a groove 301c provided at or near the proximal end 301a of the inner shaft 301. The groove 301c is coupled with the control element 403 (explained later). The inner shaft 301 is configured to move axially in response to an actuation input received by the control element 403. The inner shaft 301 is coupled to the gripping assembly 200 and facilitates the radial expansion and collapse of the gripping assembly 200 as explained later. The dimensions of the inner shaft 301 may be chosen based upon procedural requirements. In an embodiment, the length of the inner shaft 301 may range between 800 mm and 1200 mm, and the diameter of the inner shaft 301 may range between 2 mm (6 Fr) and 4 mm (12 Fr). In an example implementation, the length, and the diameter of the inner shaft 301 are 900 mm, and 3 mm (9 Fr), respectively. The inner shaft 301 may be made of a biocompatible material including, without limitation, polyurethane, PEEK, nylon, pebax, etc. In an example implementation, the inner shaft 301 is made of PEEK
[0036] The handle 400 is disposed at the proximal end 100a of the device 100. Referring to Fig. 5a, depicts a perspective view of the handle 400, according to an embodiment. The handle 400 has a proximal end 400a and a distal end 400b. The handle 400 is coupled to the outer shaft 300. In an embodiment, the distal end 400b of the handle 400 is disposed within the lumen 300c of the outer shaft 300 and coupled to the outer shaft 300 using UV bonding, medical grade adhesive, etc. In an example implementation, the distal end 400b of the handle 400 is coupled to the outer shaft 300 using UV bonding. The handle 400 may have an ergonomic design to provide a better hold and grip for medical practitioners. In an embodiment, the handle 400 is generally cylindrical and has a bulging structure 400c at the proximal end 400a. The handle 400 includes a cavity 400d extending from the distal end 400b towards the proximal end 400a. The cavity 400d is configured to receive the inner shaft 301. The handle 400 is coupled to the control element 403. In an embodiment, the handle 400 includes a slot 401 configured to receive the control element 403. The slot 401 is provided on the outer surface of the handle 400 and extends longitudinally for a partial length of the handle 400. The slot 401 has a proximal end 401a and a distal end 401b. The handle 400 may be made of a material including, without limitation, acrylonitrile butadiene styrene (ABS), a photo polymer, etc. In an example implementation, the handle 400 is made of ABS.
[0037] The control element 403 is coupled to the inner shaft 301 and facilitates the axial movement of the inner shaft 301, resulting in the radial movement of the gripping member 201. The control element 403 may be a sliding button, a roller, or the like. Fig 5b depicts a perspective view of an exemplary control element 403, according to an embodiment. In the depicted embodiment, the control element 403 is a sliding button. The control element 403 is slidably disposed in the slot 401 of the handle 400 and is movable between the proximal end 401a and the distal end 401b of the slot 401. The control element 403 includes a first portion 403a and a second portion 403b. The first portion 403a is positioned at a top end of the control element 403 and the second portion 403b is positioned at a bottom end of the control element 403. The first portion 403a allows the user to hold and manipulate the control element 403. In an embodiment, the first portion 403a includes a grip 403a1 having multiple parallel ridges provided on its top surface, that facilitates a better grip to the user and allows easier manipulation of the control element 403. It should be understood that the top surface of the grip 403a1 may have other features, such as, grooves, undulations, or the like, instead of, or in addition to, the ridges. The first portion 403a protrudes out of the slot 401 of the handle 400. The first portion 403a may have a shape, such as, without limitation, cuboidal, cylindrical, etc. In an embodiment, the first portion 403a is cuboidal. The second portion 403b extends vertically downward from the first portion 403a, forming a T-shaped structure. A top section of the second portion 403b is disposed in the slot 401 of the handle 400. The width of the slot 401 corresponds to the width of the second portion 403b. A bottom section of the second portion 403b is disposed in, and coupled to, the groove 301c of the inner shaft 301. The second portion 403b is coupled to the groove 301c of the inner shaft 301 using, a technique such as, without limitation, snap-fit, adhesive bonding, UV bonding, etc. In an example implementation, the second portion 403b is coupled to the groove 301c using UV bonding. The cross-sectional shape and dimensions of the groove 301c corresponds to the cross-sectional shape and dimensions of the second portion 403b. The second portion 403b may have a shape, such as, without limitation, cuboidal, cylindrical, etc. In an embodiment, the second portion 403b is cuboidal. The cross-sectional dimensions of the first portion 403a may be larger than the cross-sectional dimensions of the second portion 403b to prevent slippage of the control element 403 from the slot 401. The control element 403 may be made of a biocompatible material including, without limitation, ABS, a photo polymer, etc. In an example implementation, the control element 403 is made of ABS.
[0038] The control element 403 is capable of receiving a first actuation input and a second actuation input. In response to the control element 403 receiving the first actuation input, the inner shaft 301 is configured to move axially in the proximal (or backward) direction, causing the gripping member 201 to radially expand. In response to the control element 403 receiving the second actuation input, the inner shaft 301 is configured to move axially in the distal (or forward) direction, causing the gripping member 201 to radially collapse. According to an embodiment, the first actuation input and the second actuation input correspond to sliding (or moving) the control element 403 towards the proximal end 401a and the distal end 401b of the slot 401, respectively. In another embodiment, the control element 403 may be a roller (not shown). In this case, the first and section actuation inputs may correspond to rotating the control element 403 in a first and a second direction, respectively. The control element 403 may be coupled to the inner shaft 301 such that rotating the control element 403 in the first direction causes the inner shaft 301 to axially move in the proximal direction and rotating the control element 403 in the second direction causes the inner shaft 301 to axially move in the distal direction. The first direction may be clockwise and the second direction may be anticlockwise, or vice versa.
[0039] The components of the gripping assembly 200 are now explained. The gripping member 201 are configured to grip the implant. The gripping member 201 are arranged circumferentially (uniformly or non-uniformly) about the central axis of the gripping assembly 200. In an embodiment, the gripping member 201 are uniformly arranged. Consequently, the implant is gripped uniformly and a more even pressure is applied on the implant during the retrieval process, resulting in a controlled and precise retrieval, and preventing damage to the implant. The number of the gripping member 201 may be chosen based upon requirements. In an embodiment, the number of the gripping member 201 may be between 4 and 10, and preferably, between 6 and 8. In an example implementation, the gripping assembly 200 includes six gripping member 201. Fig. 6a depicts a perspective view of one gripping member 201 of the plurality of gripping member 201, according to an embodiment. The gripping member 201 has a proximal end 201a and a distal end 201b. The gripping member 201 has an elongated portion 202a at the proximal end 201a and a forked portion 202b at the distal end 201b. The elongated portion 202a may have a pre-defined shape including, without limitation, bar, rod, tube, cylinder etc. The elongated portion 202a includes a first hole 202a1 and a second hole 202a2. The first hole 202a1 is located at the proximal end 201a of the gripping member 201 and is used to couple the gripping member 201 with the proximal coupling element 203. The second hole 202a2 is located distal to the first hole 202a1 at a pre-defined distance and is used to couple the gripping member 201 with the distal coupling element 207.
[0040] The forked portion 202b is angularly tilted and makes a pre-defined angle A with the elongated portion 202a. In an embodiment the pre-defined angle A ranges from 60° to 140°. In a preferred embodiment, the pre-defined angle A is 120° such that when the gripping member 201 is in the radially expanded state, the forked portion 202b may be generally parallel to the longitudinal axis of the device 100 (as shown in Fig. 3a) and a face 202b4 may align with an inner surface of the body lumen in which the device 100 is used. This reduces trauma to the inner lining of the body lumen and/or surrounding tissues during the retrieval process. Further, the pre-defined angle A ensures that when the gripping member 201 is in the radially collapsed state, the forked portion 202b points towards the central axis of the gripping assembly 200. A tapered profile thus formed by the forked portions 202b of the gripping member 201 in the radially collapsed state (as seen in Fig. 2a) reduces trauma to vessels and/or surrounding tissues during the navigation of the device 100 and maintains secure engagement with the implant during the retrieval or repositioning. The forked portion 202b includes a plurality of prongs, spaced apart from each other. In an embodiment, the number of prongs in the forked portion 202b may be between 2 and 6, and preferably, between 2 and 4. In an example implementation, the forked portion 202b includes a first prong 202b1 and a second prong 202b2 spaced apart from the first prong 202b1, defining an opening 202b3 therebetween. The forked portion 202b is configured to grip the implant such that a portion of the implant is disposed in the opening 202b3. The prongs 202b1, 202b2 may have pre-defined shape, such as, without limitation, cylindrical, cuboidal, frustum, conical, etc. In an embodiment, the prongs 202b1, 202b2 have a finger-like shape with a taper towards a distal end of the prongs 202b1, 202b2. Such a tapered design minimizes trauma to the surrounding tissues and minimizes damage to the implant. The gripping member 201 may be made of a biocompatible material including, without limitation, stainless steel, nitinol, titanium, cobalt chromium, etc. In an example implementation, the gripping member 201 is made of stainless steel. The dimensions of the elongated portion 202a and the forked portion 202b may be chosen based on procedural requirements. In an embodiment, the length of the elongated portion 202a may range between 30 mm and 60 mm, and the length of the forked portion 202b may range between 5 mm and 20 mm. In an example implementation, the length of the elongated portion 202a and the forked portion 202b are 40 mm, and 10 mm, respectively. The length of the opening 202b3 may depend upon the design of the implant.
[0041] Fig. 6b1 depicts a perspective view and Fig. 6b2 depicts a bottom view of the proximal coupling element 203, according to an embodiment. The proximal coupling element 203 is coupled to the outer shaft 300 at the distal end 300b of the outer shaft 300. The proximal coupling element 203 serves as a fixed junction providing a stationary pivot movement to the gripping member 201 during the operation of the device 100 as explained later. The proximal coupling element 203 has a proximal end 203a and a distal end 203b. The proximal coupling element 203 has a cylindrical tubular structure and includes an opening 203c. The opening 203c may be provided centrally and extend from the proximal end 203a to the distal end 203b for the entire length of the proximal coupling element 203. The opening 203c receives a distal portion of the outer shaft 300. The opening 203c may be fixedly or removably coupled to the distal portion of the outer shaft 300 using a technique, such as, without limitation, UV bonding, medical grade adhesive, etc. In an embodiment, the opening 203c is coupled to the distal portion of the outer shaft 300 using UV bonding. The diameter of the opening 203c corresponds to the outer diameter of the outer shaft 300.
[0042] The elongated portions 202a of the gripping member 201 are pivotably coupled to the proximal coupling element 203. In an embodiment, the proximal coupling element 203 includes a plurality of projections 203d provided circumferentially on an outer surface of the proximal coupling element 203 at the proximal end 203a of the proximal coupling element 203. The projections 203d extend from the outer surface of the proximal coupling element 203 in a radially outward direction. Each projection 203d includes a hole 203e extending for the width of the projection 203d. Each projection 203d is coupled to the elongated portion 202a of a respective gripping member 201 with the help of one pin 205 as explained later. The number of projections 203d correspond to the number of gripping members 201.
[0043] The diameter of the proximal coupling element 203 may be chosen based upon the anatomy of a patient and a size of the target body lumen. In an embodiment, the diameter of the proximal coupling element 203 may range between 4 mm and 6 mm. In an example implementation, the diameter of the proximal coupling element 203 is 5 mm. The proximal coupling element 203 may be made of a biocompatible material including, without limitation, stainless steel, titanium, nitinol, cobalt chromium, etc. In an example implementation, the proximal coupling element 203 is made of stainless steel.
[0044] Fig. 6c1 depicts a perspective view and Fig. 6c2 depicts a bottom view of the distal coupling element 207, according to an embodiment. The distal coupling element 207 is disposed at the distal end 100b of the device 100. The distal coupling element 207 is coupled to the inner shaft 301 at the distal end 301b of the inner shaft 301. The distal coupling element 207 serves as a moving junction, facilitating radial movement of the gripping member 201 during the operation of the device 100 as explained later. The distal coupling element 207 is configured to move axially in response to the axial movement of the inner shaft 301. The distal coupling element 207 moves in the same direction as that of the inner shaft 301.
[0045] The distal coupling element 207 has a proximal end 207a and a distal end 207b. The distal coupling element 207 includes a cavity 207c. The cavity 207c is provided centrally and extends from the proximal end 207a towards the distal end 207b for at least a partial length of the distal coupling element 207. In an embodiment, the cavity 207c extends for a partial length of the distal coupling element 207. The cavity 207c receives a distal portion of the inner shaft 301. The cavity 207c may be fixedly or removably coupled with the distal portion of the inner shaft 301 using a technique, such as, without limitation, UV bonding, medical grade adhesive, etc. In an embodiment, the cavity 207c is coupled with the distal portion of the inner shaft 301 using UV bonding. The diameter of the cavity 207c corresponds to the outer diameter of the inner shaft 301. The distal coupling element 207 has a generally cylindrical shape. In an embodiment, the distal coupling element 207 includes a tapered section 207d at the distal end 207b such that the diameter of the tapered section 207d decreases from a proximal end of the tapered section 207d to a distal end of the tapered section 207d. The tapered section 207d reduces trauma to surrounding tissues during the navigation of the device 100 through a patient’s vasculature. The tapered section 207d may have a shape, such as, without limitation, conical, frustum, dome, etc. In an example implementation, the tapered section 207d is dome-shaped.
[0046] The elongated portions 202a of the gripping member 201 are pivotably coupled to the distal coupling element 207 with the help of the link 209. In an embodiment, the distal coupling element 207 includes a plurality of projections 207e provided circumferentially on an outer surface of the distal coupling element 207 at the proximal end 207a of the distal coupling element 207. The projections 207e extend from the outer surface of the distal coupling element 207 in a radially outward direction. Each projection 207e includes a hole 207f extending for the width of the projections 207e. The elongated portion 202a of each gripping member 201 is pivotably coupled with a respective projection 207e of the distal coupling element 207 using a link 209. Each projection 207e is coupled to one of the links 209 with the help of one pin 205 as explained later.
[0047] The pins 205 are used to couple the elongated portions 202a of the gripping member 201 with the proximal coupling element 203. The pins 205 are also used to couple the link 209 with the elongated portions 202a and the distal coupling element 207. Fig. 6d depicts a perspective view of one pin 205 of the plurality of pins 205, according to an embodiment. The pin 205 includes a rod 205a and a disc 205b provided at each end of the rod 205a. The diameter of the discs 205b is larger than the diameter of the rod 205a to prevent the pin 205 from slipping out. The rod 205a extends between the two discs 205b of the pin 205. The pin 205 may be made of a biocompatible material including, without limitation, stainless steel, titanium, nitinol, cobalt chromium, etc. In an example implementation, the pin 205 is made of stainless steel.
[0048] Fig. 6e depicts a perspective view of one link 209 of the plurality of link 209, according to an embodiment. The link 209 has a first end 209a and a second end 209b. Each link 209 is pivotably coupled to the distal coupling element 207 at the second end 209b and to the elongated portion 202a of a respective gripping member 201 at the first end 209a. The link 209 may have an elongated structure in the form of a bar, a plate, a rod or the like, having a pre-defined shape, e.g., rectangular, oval, triangular, etc. In an embodiment, the link 209 is in the form of a plate having a rectangular shape with rounded ends. The link 209 includes a first hole 209c provided at the first end 209a and a second hole 209d provided at the second end 209b. The link 209 may be made of a biocompatible material including, without limitation, stainless steel, titanium, nitinol, cobalt chromium, etc. In an example implementation, the link 209 is made of stainless steel.
[0049] An embodiment of coupling between various components of the gripping assembly 200 is now explained. The first hole 202a1 of each gripping member 201 is aligned with the hole 203e at a first end 203d1 of a respective projection 203d of the proximal coupling element 203 and coupled using one pin 205 such that a portion of the rod 205a of the pin 205 is disposed within each of the first hole 202a1 of the gripping member 201 and the hole 203e of the proximal coupling element 203. The discs 205b are disposed outside of the said holes to prevent the pin 205 from slipping out, providing a secure coupling. The diameters of the rod 205a, the first hole 202a1 of the gripping member 201 and the hole 203e of the proximal coupling element 203 correspond to each other. The pivot coupling between the gripping member 201 with the proximal coupling element 203 via the pin 205 allows the gripping member 201 to pivot (or rotate) around an axis defined by a longitudinal axis of the pin 205, causing the gripping assembly 200 to radially expand and collapse.
[0050] The second hole 202a2 of each gripping member 201 is aligned with the first hole 209c of the link 209 and coupled using one pin 205 such that a portion of the rod 205a of the pin 205 is disposed with each of the second hole 202a2 of the gripping member 201 and the first hole 209c of the link 209. The discs 205b are disposed outside of the said holes to prevent the pin 205 from slipping out, providing a secure coupling. The diameters of the rod 205a, the second hole 202a2 of the gripping member 201 and the first hole 209c of the link 209 correspond to each other. Similarly, the second hole 209d of the link 209 is aligned with the hole 207f at a first end 207e1 of a respective projection 207e of the distal coupling element 207 and coupled using one pin 205 such that a portion of the rod 205a of the pin 205 is disposed with each of the second hole 209d of the link 209 and the hole 207f of the distal coupling element 207. The discs 205b are disposed outside of the said holes to prevent the pin 205 from slipping out, providing a secure coupling. The diameters of the rod 205a, the second hole 209d of the link 209 and the hole 207f of the distal coupling element 207 correspond to each other.
[0051] An exemplary working of the gripping assembly 200 is now explained. To set the gripping assembly 200 in the radially expanded state (i.e., set the device 100 in the open configuration), the control element 403 is moved within the slot 401 towards the proximal end 401a of the slot 401. This movement causes the inner shaft 301 and the distal coupling element 207 to move axially in the proximal direction. Since the gripping member 201 are pivotably coupled to the proximal coupling element 203, which remains at a fixed position, the proximal movement of the distal coupling element 207 causes the gripping member 201 to pivot radially outward to be in the radially expanded state. When the control element 403 is positioned at the proximal end 401a of the slot 401, the gripping member 201 radially expand to the fullest and the faces 202b4 of the forked portions 202b of the gripping member 201 are substantially parallel to the longitudinal axis of the device 100. Further, a proximal face 207g of the distal coupling element 207 contacts a distal face 203f of the proximal coupling element 203. Similarly, to set the gripping assembly 200 in the radially collapsed state (i.e., set the device 100 in the closed configuration), the control element 403 is moved within the slot 401 towards the distal end 401b of the slot 401. This movement causes the inner shaft 301 and the distal coupling element 207 to move axially in the distal direction. Since the proximal coupling element 203 remains at a fixed position, the distal movement of the distal coupling element 207 causes the gripping members 201 to pivot radially inward to be in the radially collapsed state. When the control element 403 is positioned at the distal end 401b of the slot 401, the gripping members 201 radially collapse to the fullest and the faces 202b4 of the forked portions 202b of the gripping members 201 form a tapered profile as explained earlier. The radially outward and inward movement of the gripping members 201 is facilitated by the pivoted coupling of the link 209 with the gripping members 201 and the distal coupling element 207.
[0052] Fig. 7 illustrates a flowchart of a method 500 for retrieving an implant from a body lumen using the device 100, according to one embodiment. This process ensures effective engagement and safe retraction of the implant from the patient's anatomy. The method 500 may be performed under an imaging guidance technique, for example, fluoroscopy. By way of example, the method 500 has been explained for retrieving a stent 20. It should be understood that the method 500 may be similarly applied for retrieving a coil, a filter, a foreign body, etc.
[0053] At step 501, the device 100 navigated through a patient’s body to a desired position near a site where the stent 20 has been implanted. In an embodiment, the device 100 is navigated to the desired position using a guiding catheter 10. For example, the guiding catheter 10 may be inserted into the patient’s body at a desired access location (e.g., femoral access, groin access, Subclavian access, etc.). The guiding catheter 10 may be any catheter capable of being navigated to a body lumen within the patient’s body and may be chosen based upon the requirements of the procedure and the patient’s anatomy. The guiding catheter 10 includes an outer sheath 11 having a lumen 12. The device 100 may be inserted into the lumen 12 of the guiding catheter 10 such that the gripping assembly 200 is located proximal to a distal end of the guiding catheter 10, and the handle 400 and a portion of the outer shaft 300 of the device 100 protrude proximally from a proximal end of the guiding catheter 10, as shown in Fig. 8A. The distal end 100b of the device 100 is maneuvered to align with the stent 20. During the insertion and navigation of the device 100, the gripping assembly 200 is set to the radially collapsed state using the control element 403.
[0054] At step 503, the distal end 100b of the device 100 is advanced from (i.e., pushed out of) the guiding catheter 10 towards the stent 20, for example, by pushing the handle 400 of the device 100 in a distal direction, such that the distal end 100b of the device 100 is positioned at a pre-defined distance (say, 20 - 40 mm) proximal to a proximal end of the stent 20 as shown in Fig. 8B. The gripping assembly 200 is kept in the radially collapsed state.
[0055] At step 505, the gripping assembly 200 is set to the radially expanded state (i.e., the device 100 in the open configuration) using the control element 403, for example, by sliding the control element 403 towards the proximal end 401a of the slot 401 of the handle 400. Fig. 8C depicts a partial radial expansion of the gripping assembly 200. Once the gripping assembly 200 radially expands to the fullest, the position of the device 100 may be adjusted using the handle 400 such that a distal end of the prongs 202b1, 202b2 is adjacent to the proximal end of the stent 20.
[0056] At step 507, the stent 20 is engaged with the prongs 202b1, 202b2 of the gripping assembly 200 as shown in Fig. 8D. At this stage, a portion of the stent 20 is disposed in the opening 202b3 of the prongs 202b1, 202b2, ensuring initial anchoring of the stent 20 with the gripping assembly 200.
[0057] At step 509, the gripping assembly 200 is set to the radially collapsed state using the control element 403, for example, by sliding the control element 403 towards the distal end 401b of the handle 400. The sliding movement of the control element 403 causes the forked portions 202b of the gripping member 201 to retract inwardly, which firmly secures the stent 20 with the gripping assembly 200 as shown in Fig. 8E and Fig. 8F.
[0058] At step 511, the gripping assembly 200 is retracted within the guiding catheter 10, for example, by pulling the handle 400 in the proximal direction. Fig. 8G depicts a stage where a portion of the stent 20 is inside the guiding catheter 10. Due to the constraining force applied by the outer sheath 11, the portion of the stent 20 inside the outer sheath 11 is radially collapsed/crimped. The surgeon may continue to pull the handle 400 until the stent 20 is fully disposed within the outer sheath 11 of the guiding catheter 10 (as shown in Fig. 8H) and the entire length of the stent 20 is radially collapsed. The radially collapsing structure of the gripping assembly 200 ensures that the stent 20 is retrieved without damaging the stent 20 and without damaging the surrounding tissue or structures.
[0059] At step 513, the device 100 is withdrawn from the patient’s body. The guiding catheter 10 is also withdrawn. Thus, the method 500 ensures that stent 20 is completely retrieved in a controlled and precise manner without any damage to the structure of the stent 20.
[0060] A similar method may be followed for repositioning the stent 20. In this case, steps 501 – 511 may be performed until the stent 20 is completely disposed within the outer sheath 11 of the guiding catheter 10. The position of the guiding catheter 10 is then adjusted to a desired location where the stent 20 is to be re-positioned. The outer sheath 11 may then be retracted to expose the stent 20 while keeping the stent 20 engaged with the gripping assembly 200. The gripping assembly 200 is then set to the radially expanded state in a similar manner as explained earlier. Once the surgeon verifies that the stent 20 is positioned correctly as desired, the device 100 may be moved in a proximal direction, releasing the stent 20 from the gripping assembly 200. The gripping assembly 200 is then set to the radially collapsed and is retracted inside the guiding catheter 10. The device 100 (and the guiding catheter 10) may then be withdrawn from the patient’s body.
[0061] The proposed device presents several advantages over the conventional stent removal and repositioning devices. The device offers a solution for retrieving or repositioning implants with enhanced efficiency and safety. The device ensures complete and secure capture of the implant, significantly reducing procedural time and minimizing the need for multiple surgeries. The device includes a switch-operated mechanism, facilitating precise control during the retrieval and increasing the ease of use. Additionally, adaptable design of the device allows it to accommodate various anatomical structures, reducing the risk of vascular trauma. Overall, the device enhances reliability, versatility, and ease of use, addressing critical challenges like incomplete retrieval and high procedural complexity, thus improving overall surgical outcomes as compared to conventional devices.
[0062] 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 device (100) for retrieving an implant from a body lumen, the device (100) comprising:
a. a proximal coupling element (203);
b. a distal coupling element (207);
c. a plurality of gripping members (201), each gripping member (201) comprising:
i. an elongated portion (202a) pivotably coupled to the proximal coupling element (203) and the distal coupling element (207); and
ii. a forked portion (202b) configured to engage with an implant, the forked portion (202b) comprising a plurality of prongs spaced apart from each other; and
d. a control element (403) coupled to the distal coupling element (207) and capable of receiving a first actuation input and a second actuation input;
wherein in response to the control element (403) receiving the first actuation input, the distal coupling element (207) is configured to move axially in a proximal direction, causing the plurality of gripping member (201) to radially expand;
wherein in response to the control element (403) receiving the second actuation input, the distal coupling element (207) is configured to move axially in a distal direction, causing the plurality of gripping member (201) to radially collapse.
2. The device (100) as claimed in claim 1, wherein the device (100) comprises:
a. an outer shaft (300); and
b. an inner shaft (301) disposed within the outer shaft (300) and coupled to the control element (403);
wherein the proximal coupling element (203) and the distal coupling element (207) are coupled to the outer shaft (300) and the inner shaft (301), respectively;
wherein in response to the control element (403) receiving the first and the second actuation input, the inner shaft (301) is configured to move axially in the proximal and the distal direction, respectively.
3. The device (100) as claimed in claim 2, wherein one or more of:
a. the proximal coupling element (203) comprises an opening (203c) configured to receive, and coupled with, a distal portion of the outer shaft (300).
b. the distal coupling element (207) comprises a cavity (207c) configured to receive, and couple with, a distal portion of the inner shaft (301).
4. The device (100) as claimed in claim 2, wherein the device (100) comprises a handle (400) provided at a proximal end (100a) of the device (100) and coupled to the outer shaft (300), the handle (400) comprising a cavity (400d) configured to receive the inner shaft (301).
5. The device (100) as claimed in claim 2, wherein the inner shaft (301) comprises a groove (301c) coupled with the control element (403).
6. The device (100) as claimed in claim 1, wherein the forked portion (202b) is angularly tilted and makes a pre-defined angle A with the elongated portion (202a).
7. The device (100) as claimed in claim 6, wherein the pre-defined angle A ranges from 60° to 140°.
8. The device (100) as claimed in claim 6, wherein the pre-defined angle A is equal to 120°.
9. The device (100) as claimed in claim 1, wherein the control element (403) is slidably disposed within a slot (401) provided in a handle (400) and movable between a proximal end (401a) and a distal end (401b) of the slot (401), wherein the first actuation input and the second actuation input comprise moving the control element (403) towards the proximal end (401a) and towards the distal end (401b) of the slot (401), respectively.
10. The device (100) as claimed in claim 1, wherein the forked portion (202b) comprises a first prong (202b1) and a second prong (202b2) having an opening (202b3) therebetween, wherein the opening (202b3) is configured to receive a portion of the implant.
11. The device (100) as claimed in claim 1, wherein the proximal coupling element (203) comprises a plurality of projections (203d) provided circumferentially on an outer surface of the proximal coupling element (203), wherein a first hole (202a1) of the elongated portion (202a) of each gripping member (201) is pivotably coupled with a hole (203e) of a respective projection (203d) of the proximal coupling element (203) using a pin (205).
12. The device (100) as claimed in claim 1, wherein the distal coupling element (207) comprises a plurality of projections (207e) provided circumferentially on an outer surface of the distal coupling element (207), wherein the elongated portion (202a) of each gripping member (201) is pivotably coupled with a respective projection (207e) of the distal coupling element (207) using a link (209).
13. The device (100) as claimed in claim 12, wherein each link (209) comprises a first hole (209c) and a second hole (209d) coupled to a second hole (202a2) of the elongated portion (202a) of a respective gripping member (201) and a hole (207f) of a respective projection (207e) of the distal coupling element (207), respectively, using a pin (205).
14. The device (100) as claimed in claim 1, wherein the implant comprises one of: a stent, a coil, or a filter.
15. The device (100) as claimed in claim 1, wherein the distal coupling element (207) includes a tapered section (207d) at a distal end (207b) of the distal coupling element (207) such that a diameter of the tapered section (207d) decreases from a proximal end to a distal end of the tapered section (207d).