Asymmetrical bending medical device

Abstract

To provide endoscopic medical devices and methods of use.SOLUTION: An articulation joint 50 includes proximal links 52, distal links 56, and intermediate links 54 connecting the proximal and distal links. The articulation joint has a straight configuration along a straight longitudinal axis, a first bent configuration when the articulation joint bends toward a first side of the longitudinal axis, and a second bent configuration when the articulation joint bends toward a second side of the longitudinal axis, opposite to the first side. When the articulation joint is in the straight configuration, a first gap G is defined at a first side 58a between adjacent proximal links, where the adjacent proximal links are in contact with each other at a second side 58b, a second gap I is defined at each of the first and second sides between adjacent distal links, a third gap H is defined at the first side between adjacent intermediate links, and the adjacent intermediate links are in contact with each other at the second side.SELECTED DRAWING: Figure 4B

Description

Technical Field

[0001] The present invention generally relates to endoscopic medical devices and methods of use. More particularly, the present invention relates to endoscopes and related methods for accessing a target site having spatial constraints, for example, endoscopes using a flexible steering shaft such as an articulation joint at the distal end of the endoscope and related methods.

Background Art

[0002] Endoscopic devices generally include a flexible shaft, a working distal end, and a flexible steering shaft that connects the working tip and the flexible shaft. The flexible steering shaft includes a bendable articulation joint. Disadvantages of conventional endoscopes include, for example, the inability to form a small bending radius when the articulation joint forms both a large bending angle and a small bending angle. For example, an articulation joint that forms a full reverse bend (bending the articulation joint to visualize in the proximal direction, e.g., bending the articulation joint to visualize the entry point of the endoscope into the patient's stomach) generally requires the articulation joint to bend more than about 210 degrees. When the same conventional articulation joint is bent to a position less than 210 degrees, e.g., 90 degrees, the articulation joint rotates gradually with a large radius and is not suitable for areas of the human body with spatial constraints. These disadvantages can prevent a physician from properly visualizing or accessing a body part during surgery. potal) requires the articulation joint to bend more than about 210 degrees. When the same conventional articulation joint is bent to a position less than 210 degrees, e.g., 90 degrees, the articulation joint rotates gradually with a large radius and is not suitable for areas of the human body with spatial constraints. These disadvantages can prevent a physician from properly visualizing or accessing a body part during surgery.

[0003] Therefore, it is desirable that the articulation joint forms the narrowest acceptable bending radius when the articulation joint is bent to its maximum angle, and achieves the same or similar narrowest acceptable bending radius when the articulation joint is bent to a smaller angle. The present invention can solve one or more of these problems or other problems in the art. However, the scope of the present invention is defined by the appended claims rather than by its ability to solve a particular problem. [Overview of the Initiative]

[0004] For example, an articulation joint of a medical device includes a proximal link, a distal link, and an intermediate link connecting the proximal and distal links. The articulation joint has a linear form along a straight longitudinal axis, a first bent form when the articulation joint is bent toward a first side of the longitudinal axis, and a second bent form when the articulation joint is bent toward a second side of the longitudinal axis, which is opposite to the first side. When the articulation joint is in the linear form, a first gap is formed on the first side between adjacent proximal links, and adjacent proximal links are in contact with each other on the second side; a second gap is formed on the first and second sides between adjacent distal links; and a third gap is formed on the first side between adjacent intermediate links, and adjacent intermediate links are in contact with each other on the second side.

[0005] When the articulation joint is in the first bent form, the sizes of the first, second, and third gaps on the first side are smaller than the sizes of the first, second, and third gaps on the first side when the articulation joint is in the straight form.

[0006] When the articulation joint is fully bent toward the first side, the surfaces of adjacent links come into contact with each other such that the first, second, and third gaps on the first side are zero.

[0007] When the articulation joint is in the second bent form, the size of the second gap on the second side is smaller than the size of the second gap on the second side when the articulation joint is in the straight form.

[0008] The distal link is movable in exactly four directions, the proximal link is movable in exactly one direction, and the intermediate link is movable in two or three directions. The articulation joint includes a third bending configuration toward a third side of the longitudinal axis midway between the first and second sides, and a fourth bending configuration when the articulation joint bends toward a fourth side of the longitudinal axis opposite to the third side, and when the articulation joint is in a straight configuration, a fourth gap is formed on each of the third and fourth sides between adjacent distal links, and a fifth gap is formed on each of the third and fourth sides between adjacent intermediate links.

[0009] When the articulation joint is in the third bent configuration, the sizes of the fourth and fifth gaps on the third side are smaller than the sizes of the fourth and fifth gaps on the third side when the articulation joint is in the straight configuration, and when the articulation joint is in the fourth bent configuration, the sizes of the fourth and fifth gaps on the fourth side are smaller than the sizes of the fourth and fifth gaps on the fourth side when the articulation joint is in the straight configuration.

[0010] The fourth and fifth gaps are offset from the first, second, and third gaps along the longitudinal axis. The articulation joint may move simultaneously in either the first or second direction and in either the third or fourth direction.

[0011] The proximal, distal, and intermediate links of the articulation joint are each attached to adjacent links by a first spring and a second spring, and the first and second springs of the attached links are located on the circumferentially opposing sides of the articulation joint.

[0012] The first and second springs can be attached to the inner surfaces of the proximal link, distal link, and intermediate link, respectively, by welding, brazing, soldering, or adhesive. When the first spring and the second spring are in a linear configuration, adjacent coils of the first spring and the second spring are in contact with each other.

[0013] The first and second springs each define a lumen for accommodating the articulation element. The bending angles corresponding to the first, second, third, fourth, and fifth gaps are equal.

[0014] The articulation joint includes a tip portion attached to the distal end of the distal link, which includes one or more of the following for the passage of imaging devices, illumination devices, end effectors, and secondary devices.

[0015] The accompanying drawings incorporated herein, and which constitute part thereof, illustrate various exemplary embodiments and, together with the description, help to illustrate the principles of the disclosed embodiments. [Brief explanation of the drawing]

[0016] [Figure 1] A perspective view showing a medical device according to one embodiment. [Figure 2] A cross-sectional view showing the articulation joint of the medical device shown in Figure 3, along line AA. [Figure 3] A perspective view showing the articulation joint in Figure 2. [Figure 4A] A side view showing the articulation joint in Figure 3. [Figure 4B] A side view showing the articulation joint in Figure 3. [Figure 4C] A side view showing the articulation joint in Figure 3. [Figure 4D] A side view showing the articulation joint in Figure 3. [Figure 4E] A side view showing the articulation joint in Figure 3. [Figure 4F] A side view showing the articulation joint in Figure 3. [Modes for carrying out the invention]

[0017] The general description above and the detailed description below are both illustrative and descriptive and do not limit the features as described in the claims. Where used herein, terms such as “equipped,” “possessing,” “having,” “including,” or other variations thereof are intended to be non-exclusive; therefore, a process, method, article, or apparatus comprising a list of elements may not include only those elements but may include other elements not expressly enumerated, or other elements specific to such a process, method, article, or apparatus. In this invention, relative terms such as, for example, “about,” “substantially,” “generally,” and “approximate” are used to indicate a possible variation of ±10% of the stated value or characteristic.

[0018] Refer to Figure 1, which shows an endoscope 10 according to one embodiment. The endoscope 10 includes a flexible shaft 20, a distal end tip 30 of the endoscope 10, and an articulation joint 50 positioned between the flexible shaft 20 and the tip 30 to connect the flexible shaft 20 and the tip 30. Other devices, such as a handle 40 for driving or controlling the endoscope 10, and any instruments or devices associated with the endoscope 10 are connected to the proximal end of the flexible shaft 20.

[0019] A plurality of drive elements 12, such as cables or wires (e.g., medical grade plastic or metal) suitable for medical procedures, extend distally from the proximal end of the endoscope 10. The drive elements 12 are shown, for example, between adjacent links in FIGS. 4A-4F. The drive elements 12 extend into the handle 40 and are indirectly coupled to first and second drive devices 42, 43 that control the articulation of the articulation joint 50 in multiple directions. The devices 42, 43 are rotatable knobs, for example, that rotate about the axes of the devices 42, 43 to push / pull the drive elements 12. Additionally or alternatively, the user can operate the drive elements 12 independently of the handle 40. The distal end of the drive element 12 extends through the flexible shaft 20 and terminates at the articulation joint 50 and / or the tip 30. For example, one or more drive elements 12 can be connected to the articulation joint 50 and one or more drive elements 12 can be attached to the tip 30. As described herein, driving the drive elements 12 can control the driving of elements attached to the tip 30, such as the articulation joint 50, the tip portion 30, and / or an end effector (not shown). Further, one or more electrical cables (not shown) extend from the proximal end of the endoscope 10 to the tip portion 30 to provide electrical control for imaging, illumination, and / or other electrical devices at the tip portion 30 and to convey image signals from the tip portion 30 proximally for processing or displaying on a display. The handle 40 also includes ports 44, 46 for introducing or removing instruments, fluids, or other materials from the patient's body. Port 44 can be used to introduce instruments. Port 46 can be connected to the umbilicus for introducing fluid suction and / or making wiring connections for electronic components.

[0020] As shown in FIG. 2, the articulation joint 50 includes a portion of the lumen 22 that extends through the endoscope 10. The articulation joint 50 also includes a plurality of springs 24. For ease of understanding, only a portion of the plurality of springs 24 is shown in FIG. 3. Further, for ease of understanding, in FIGS. 4A - 4F, the springs 24 are omitted (the springs 24 are disposed between a pair of laser welds 28 described below). The springs 24 connect adjacent links of the articulation joint 50 as described in more detail herein. The lumen 22 extends from the handle 40 through the flexible shaft 20 into the articulation joint 50 and through the distal end of the tip 30. The endoscope 22 can receive devices such as instruments and imaging devices associated with the endoscope 10 for performing endoscopic surgery. Further, materials such as tissue samples are removed from the patient's body through the lumen 22. The endoscope 10 including the flexible shaft 20 and the articulation joint 50 is not limited to a single lumen 22 and may include any number of lumens necessary to perform the surgery. Additionally or alternatively, one or more catheters (not shown) can be introduced through the lumen 22 to remove tissue or insert instruments.

[0021] Continuing to refer to FIG. 2, the spring 24 defines a drive hole 25 that receives the drive element 12. According to one example, one or more drive elements 12 are disposed in the drive hole 25 of each spring 24. Additional drive holes, such as eyelets (not shown), extend from the proximal end to the distal end of the flexible shaft 20 and can prevent the drive element 12 from becoming entangled or adversely affecting the operation of the endoscope 10 by providing a path through which the drive element 12 can extend.

[0022] Referring to Figure 3, the most distal link 29 is connected to the tip 30. The tip 30 may include a camera (not shown), lighting, electronic equipment (such as a printed circuit board), an end effector or instrument (not shown), or any other device used in a therapeutic or diagnostic procedure. The tip 30 may include multiple elements, such as both a camera and an end effector, to visualize a target site and collect a sample from the target site.

[0023] The articulation joint 50 will be described with reference to Figures 3 and 4A-4F. The articulation joint 50 has a plurality of substantially cylindrical links with a plurality of gaps between the links. For example, as shown in Figure 3, the articulation joint 50 includes a first proximal link portion 52, a third distal link portion 56, and a second intermediate link portion 54 provided between the first link portion 52 and the third link portion 56 to connect the first link portion 52 and the third link portion 56. The first, second, and third link portions 52, 54, and 56 are formed from a first link type 50a, a second link type 50b, and a third link type 50c, respectively (see Figure 4C). In one example, the first, second, and third link types 50a, 50b, and 50c may be the same or different in shape and / or size. For example, the first link type 50a is longer along the longitudinal axis A than the second and third link types 50b and 50c. Unless otherwise specified, the first link type 50a, the second link type 50b, and the third link type 50c are generally referred to as “links”. Links are formed, for example, by laser cutting a tube (such as a metal tube, a plastic tube, or other medical-grade material known in the art), but are not limited to being formed in this manner.

[0024] Furthermore, as shown in Figures 2 and 3, the spring 24 connects adjacent links in the first, second, and third link sections 52, 54, and 56, respectively. Additionally, the spring 24 connects the furthest link of the first link section 52 to the nearest link of the second link section 54, the furthest link of the second link section 54 to the nearest link of the third link section 56, and / or the furthest link of the third link section 56 to the furthest link 29. As will be described in more detail herein, adjacent links can be bent relative to each other through the flexibility of the spring 24, as space is provided between the links. While the example shows two springs 24 connecting adjacent links, the present invention is not limited to this configuration. In one example, the spring 24 is attached to the inner surface of the articulation joint 50, for example, by laser welding, adhesive, rivet, or any other technique known in the art. For example, laser welding 28 is shown in Figure 3 at the location where spring 24 is attached to an adjacent link.

[0025] As shown in Figures 4B and 4E, the articulation joint 50 is linear in shape and includes a longitudinal axis A extending through the centers of the first, second, and third link sections 52, 54, and 56. The articulation joint 50 is configured to bend in four different directions (e.g., up, down, left, and right) that are 90 degrees apart from each other about axis A. The bending directions are designated as the first side 58a, the second side 58b, the third side 58c, and the fourth side 58d, each about 90 degrees from the adjacent side. The first side 58a is opposite the second side 58b (about 180 degrees apart), and the third side 58c is opposite the fourth side 58d (about 180 degrees apart). As shown in Figures 4A, 4C, 4D, and 4F, the links are bent relative to each other in each of the first, second, and / or third link sections 52, 54, and 56. Furthermore, as shown in Figures 4A to 4F, the springs 24 are located only on two adjacent sides of the first link section 52, for example, the third side 58c and the fourth side 58d. As will be described in more detail below, the springs 24 are located on the first, second, third, and fourth sides 58a, 58b, 58c, and 58d of the second link section 54 and the third link section 56.

[0026] As shown in Figures 4C and 4F, each link includes an end face 51 facing an adjacent link, and in some cases, the end face 51 of the adjacent link contacts the articulation joint 50 when the articulation joint 50 is in a linear configuration. For example, the end face 51 of the first link 50a contacts the end face 51 of the adjacent link 50a on one of the four sides of the articulation joint 50 (e.g., the second side 58b) when the articulation joint 50 is in a linear configuration (the contact includes point contact between adjacent end faces 51 on the second side 58b of the adjacent link 50a and / or contact between adjacent surfaces 51 of the adjacent link 50a moving from the second side 58b toward one or both of the first and third sides 58a, 58c in the circumferential direction of the articulation joint 50). For ease of understanding, only some of the end faces 51 are identified by reference numbers in Figures 4A-4F. However, it can be seen that end faces 51 are provided at both ends of all links.

[0027] On the first side 58a of the first link section 52, the end face 51 of one link 50a is spaced apart from the end face 51 of an adjacent link 50a, and as the articulation joint 50 bends toward the first side 58a, it approaches the end surface 51 of the adjacent link 50a, and when the articulation joint 50 is fully bent toward the first side 58a, as shown in Figure 4A, it contacts the end face 51 of the adjacent link 50a. As described above, the spring 24 connects adjacent links 50a on only two sides, for example, a third side 58c and a fourth side 58d. Furthermore, the spring 24 is a tightly wound coil spring with no space between adjacent coils when the spring is in a linear configuration. For this reason, links having the first link type 50a on the first link section 52 cannot bend toward the third side 58c or the fourth side 58d. Therefore, according to one embodiment, the link 50a of the first link portion 52 bends in one direction, for example toward the first side 58a.

[0028] Furthermore, as shown in Figures 4B and 4E, when the articulation joint 50 is in a linear configuration, the end face 51 of the second link 50b contacts the end face 51 of the adjacent link 50b only on one side, i.e., only on the second side 58b. When the articulation joint 50 is in a linear configuration, the end face 51 of the third link type 50c does not contact the end face 51 of the adjacent link 50c. When the second link 50b is bent toward the first side 58a, the end face 51 of the second link 50b contacts the end face 51 of the adjacent second link 50b. When the third link 50c is bent toward the first or second side 58a, 58b, the end face 51 of the third link 50c contacts the end face 51 of the adjacent third link 50c. Contact between the end faces 51 of adjacent links prevents the adjacent links of the articulation joint 50 from bending further, resulting in maximum bending of the articulation joint 50 in that particular direction.

[0029] Furthermore, as shown in Figures 4A to 4F, the springs 24 are attached to all four sides 58a, 58b, 58c, and 58d of the second link section 54 and the third link section 56. However, the springs 24 are attached to adjacent links in an offset position. For example, three adjacent links 100 (see Figure 3) include two pairs of adjacent links. The first pair of adjacent links 100A and 100B are attached together by springs 24 on the first and second sides 58a and 58b, so that the first pair of adjacent links 100A and 100B cannot bend toward each other toward the first and second sides 58a and 58b. The second pair of adjacent links 100B and 100C are attached together via springs 24 on the third and fourth sides 58c and 58d. Therefore, the second pair of adjacent links 100B, 100C cannot bend toward each other toward the third and fourth sides 58c, 58d due to the arrangement of the springs 24.

[0030] Each adjacent link in the first, second, and third link sections 52, 54, and 56 can bend relative to each other in at least one direction. The angle at which adjacent links can bend, and the spacing between these adjacent links, may be equal to the minimum bending radius that the imaging wire and other components can bend while maintaining their function. For example, the maximum bending angle B of adjacent links spaced 0.3 to 0.7 inches apart is about 20 to 40 degrees, preferably about 25 to 35 degrees between adjacent links spaced 0.4 to 0.6 inches apart, and more preferably about 30 degrees between links spaced 0.5 inches apart.

[0031] In Figures 4A to 4C, the longitudinal axis A extends along the Y-axis, and the articulation joint 50 bends in the YZ plane. As shown in Figure 4B, a first gap G is provided along the first side 58a of the articulation joint, between adjacent links in the first link section 52, and between the furthest link of the first link section 52 and the nearest link of the second link section 54. A second gap H is provided between adjacent links in the second link section 54 on the first side 58a. A third gap I is provided on both the first side 58a and the second side 58b, between the links of the third link section 56, and between the furthest link of the third link section 56 and the furthest link 29.

[0032] The first, second, and third gaps G, H, I allow the articulation joint 50 to bend by an amount equal to the bending angle B multiplied by the total number of gaps. For example, if the bending angle B is 30 degrees and there are a total of seven gaps on the first side 58a, the articulation joint 50 bends 210 degrees from the longitudinal axis A, allowing the tip 30 to face the entry point of the endoscope 10 into the patient's body. The sizes of the gaps G, H, and I can be varied to achieve the desired bending angle. The bending angle is merely an example, and the bending angle of each different gap may vary depending on the type of gap; for example, different gaps G may have different bending angles.

[0033] For example, a third gap I on the second side 58b allows the adjacent link to bend at the same angle B as the first gap G. However, the angle corresponding to the third gap I on the second side 58b is not limited to angle B, but may be any angle that optimizes the bending angle of the articulation joint 50. As shown in Figure 4C, the third gap I allows the third link section 56 and the furthest link 29 to bend toward the second side 58b from the longitudinal axis A, but the first link section 52 and the second link section 54 do not bend toward the second side 58b; that is, the first link section 52 and the second link section 54 remain coaxial with the longitudinal axis A. This configuration allows the articulation joint 50 to bend 90 degrees toward the second side 58b. This bending is performed by bending through only a few gaps, specifically by bending using only the third gap I, thereby reducing the bending radius of the articulation joint 50, and allowing the articulation joint 50 to bend in a smaller space. Although the second link portion 54 is shown to be bendable in three directions, in some examples the second link portion 54 may only be bendable in two directions.

[0034] In Figures 4D-4F, the vertical axis A extends to the Y-axis, and the articulation joint is bent 50 degrees in the XY plane. As shown in Figure 4E, the second link section 54 and the third link section 56 include a number of fourth gaps J on the third side 58c and on the fourth side 58d of the articulation joint 50 opposite the third side. The fourth gaps J are also located between the farthest link of the second link section 54 and the nearest link of the third link section 56, and between the farthest link of the third link section 56 and the farthest link 29. The fourth gaps J are not present in the first link section 52. For example, the fourth gaps J allow adjacent links to bend at the same angle B as the angles corresponding to the first, second, and third gaps G, H, I. However, the angle corresponding to the fourth gaps J is not limited to angle B and may be any angle that optimizes the bending angle of the articulation joint 50. As further shown by comparing Figure 4B with Figure 4E, the fourth gap J is offset from or alternates with the first, second, and third gaps G, H, I along the longitudinal axis A. For example, as described above, adjacent links bend relative to each other in the first and / or second directions 58a, 58b, but not in the third and fourth directions 58c, 58d, based on the arrangement of the spring 24. Similarly, adjacent links can bend relative to each other in the third and / or fourth directions 58c, 58d, but not in the first and second directions 58a, 58b. Thus, in some examples, bending a portion of the articulation joint 50 can bend two adjacent links together (for example, the first pair of adjacent links 100A, 100B may bend relative to each other toward one or the other).

[0035] The articulation joint 50 can bend in the XY plane with respect to the longitudinal axis A. For example, if the bending angle B is 30 degrees and there are four gaps J on each of the third side 58c and the fourth side 58d, the articulation joint 50 can bend 120 degrees relative to the first link section 52 in both left and right directions, i.e., toward the third side 58c and the fourth side 58d (i.e., the second and third link sections 54 and 56 are offset 120 degrees from the longitudinal axis A). This configuration also reduces the bending radius of the articulation joint 50 by limiting the number of gaps required to achieve the desired bending angle of the articulation joint 50, enabling greater maneuverability in a smaller space. When the articulation joint 50 bends toward one or more sides, the surfaces forming the gaps on those sides approach each other until the surfaces contact each other and the respective gaps are completely closed. The size of the gap on the side opposite to the bending side increases. Similarly, when the articulation joint 50 returns from a bent position to a straightened form, the closed gap opens again, and the size of the gap on the side opposite the bent side decreases. The angles of the gap J on the third side 58c and the angles of the gap J on the fourth side 58d do not need to be equal to each other, and / or the total deviation of the articulation joint 50 from the longitudinal axis A does not need to be the same. For example, if the gaps are located on the third side 58c and / or the fourth side 58d, and the number of gaps and / or the bending angles of the gaps on the third side 58c are different from the number of gaps and / or the bending angles of the gaps on the fourth side 58d, then different bend shapes may result when the articulation joint 50 is fully bent.

[0036] Those skilled in the art will understand that various modifications and variations can be made to the disclosed apparatus without departing from the scope of the present invention. For example, the configuration of gaps and links, and the bending angles can be changed to suit any medical device. The bending angles, the size of each gap, and / or the number of gaps and links are not limited to the examples described herein. Other embodiments of the present invention will be understood by those skilled in the art who practice the invention disclosed herein in consideration of this specification. This specification and the examples are intended to be considered merely illustrative, and the true scope and spirit of the present invention are shown by the following claims.

Claims

1. In an articulation joint for an endoscope, the articulation joint is, The articulation joint includes a plurality of proximal links, a plurality of distal links, and a plurality of intermediate links connecting the plurality of proximal links and the plurality of distal links, and the articulation joint has a linear longitudinal axis in the linear form of the articulation joint, The plurality of proximal links are movable only toward the first side of the articulation joint so as to be spaced apart from the linear longitudinal axis. The plurality of distal links are movable toward the first, second, third, and fourth sides of the articulation joint so as to be spaced apart from the linear longitudinal axis. The plurality of intermediate links are movable only toward the first, third, and fourth sides of the articulation joint so as to be spaced apart from the linear longitudinal axis. The articulation joint further comprises a plurality of gaps at the position where the articulation joint bends in the linear configuration. The aforementioned multiple gaps are, One or more first gaps, each defined on the first side between the adjacent plurality of proximal links, One or more third gaps defined on the first and second sides, respectively, between the adjacent plurality of distal links, It comprises one or more second gaps, each defined on the first side between the adjacent plurality of intermediate links, An articulation joint for an endoscope, wherein, in the linear configuration, the plurality of adjacent proximal links contact each other on the second side opposite the first side, and the plurality of adjacent intermediate links contact each other on the second side.

2. The articulation joint according to claim 1, wherein when the articulation joint is fully bent toward at least one of the first side, the second side, the third side, and the fourth side, the surfaces of the adjacent plurality of distal links are in contact with each other along the corresponding side, and the size of the plurality of gaps along the corresponding side is zero.

3. The articulation joint according to claim 1 or 2, wherein the articulation joint is configured to move simultaneously toward either the first side or the second side, and toward either the third side or the fourth side.

4. The articulation joint according to any one of claims 1 to 3, wherein each of the plurality of proximal links, plurality of distal links, and plurality of intermediate links of the articulation joint is attached to an adjacent link by a first spring and a second spring, the first and second springs being arranged on opposing sides in the circumferential direction of the articulation joint.

5. The articulation joint according to claim 4, wherein each of the first springs and each of the second springs is attached to the inner surface of each of the plurality of proximal links, the plurality of distal links, and the plurality of intermediate links by at least one of laser welding and adhesive.

6. The articulation joint according to claim 4 or 5, wherein when the first and second springs are in a linear configuration, the adjacent coils of each of the first and second springs are in contact with each other.

7. The articulation joint according to any one of claims 4 to 6, wherein each of the first springs and each of the second springs defines a lumen for housing a drive element.

8. The articulation joint according to claim 1, wherein the bending angles corresponding to each of the plurality of gaps are equal.

9. The articulation joint according to any one of claims 1 to 8, further comprising a tip portion attached to the distal end of the plurality of distal links, wherein the tip portion includes one or more of an imaging device, an illumination device, and an end effector.

10. Each of the first springs and each of the second springs, configured to be attached to a first pair of a plurality of adjacent links including a first link and a second link, is located on the first side of the articulation joint and on the second side of the articulation joint, The articulation joint according to claim 4, wherein each of the first springs and each of the second springs, configured to be attached to a second pair of a plurality of adjacent links including the second link and the third link, are located on the third side of the articulation joint, which is midway between the first and second sides, and on the fourth side of the articulation joint, which is opposite to the third side.

11. When the articulation joint is in the first bending configuration, the articulation joint bends to a first bending angle which is the first maximum bending angle. When the articulation joint is in the second bending configuration, the articulation joint bends to a second bending angle which is the second maximum bending angle. The articulation joint according to any one of claims 1 to 10, wherein the first maximum bending angle is greater than the second maximum bending angle.

12. The articulation joint according to claim 11, wherein the first maximum bending angle is at least 210 degrees.

13. When the articulation joint is in the third bending configuration, the articulation joint bends to the third maximum bending angle. When the articulation joint is in the fourth bending configuration, the articulation joint bends to a fourth bending angle, which is the fourth maximum bending angle. The articulation joint according to claim 11 or 12, wherein the third maximum bending angle is equal to the fourth maximum bending angle.

14. The articulation joint according to claim 13, wherein the third and fourth maximum bending angles are 120 degrees.

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