Cannula

Abstract

To provide a cannula seal assembly with a compatible flexible cannula.SOLUTION: A cannula 10 includes a rigid cannula body 16 having a proximal end 12 and a distal end 14. The cannula body is composed of material having a first thickness. A flexible thread 28 extends along at least a portion of the cannula body from the distal end toward the proximal end. The thread is composed of material having a second thickness, which is less than the first thickness. The cannula is attachable to a cannula seal assembly. The assembly includes a housing having a primary seal and a secondary seal therein. The assembly has a spacer connected between the primary and secondary seals, and a reservoir between the primary and secondary seals.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 785,331, entitled "Cannula Seal Mechanism," filed December 27, 2018, and U.S. Provisional Patent Application No. 62 / 786,085, entitled "Soft-Thread Cannula," filed December 28, 2018, both of which are incorporated herein by reference in their entireties.

[0002] FIELD OF THE INVENTION The present invention relates to surgical devices and assemblies, and more particularly to cannula seal assemblies with interchangeable flexible cannulas. [Background technology]

[0003] 2. Description of Related Art Cannulas are used to assist in arthroscopic or endoscopic procedures by providing portal access to the surgical site. Due to fluid management concerns, cannulas often include a seal at the proximal end. The seal restricts fluid flow through the cannula but can also contribute to the generation of fluid pressure. Disturbing the seal by passing an instrument or device through the cannula can result in spontaneous and uncontrolled gush of fluid leakage.

[0004] Additionally, conventional cannulas often have a rigid body with rigid threads. The rigid body maintains a tube-like structure for passing instruments and devices, and the rigid threads grip tissue at the surgical site and provide fixation for the cannula. However, the rigid threads on the cannula body can cause additional trauma and risk of injury at the surgical site when the cannula is inserted.

[0005] Therefore, there is a need for a cannula having flexibility features to reduce trauma and a seal assembly to control fluid egress from the surgical site when passing instruments to the surgical site.

[0006] Related Art Description Section Disclaimer: To the extent that specific patents / publications / products are described in this Related Art Description Section or elsewhere in this disclosure, these descriptions should not be construed as an admission that the described patents / publications / products are prior art under patent law. For example, some or all of the described patents / publications / products may not be early enough in time, may not reflect subject matter developed early enough in time, and / or may not be sufficiently effective to amount to prior art for purposes of patent law. To the extent that a specific patent / publication / product is discussed above in this Related Art Description Section and / or throughout the application, that description / disclosure is incorporated herein by reference in its entirety. Summary of the Invention

[0007] Embodiments of the present invention are directed to a cannula seal assembly with an interchangeable flexible cannula. According to one aspect, the invention is a cannula including a rigid cannula body having a proximal end and a distal end. The cannula body is constructed from a material having a first thickness. A flexible thread extends along at least a portion of the cannula body from the distal end toward the proximal end. The thread is constructed from a material having a second thickness that is less than the first thickness. It is composed.

[0008] According to another aspect, the cannula includes a rigid cannula body having a proximal end and a distal end. A flexible sleeve extends along at least a portion of the cannula body from the distal end toward the proximal end. The cannula also includes a flexible thread extending along at least a portion of the sleeve.

[0009] According to another aspect, the present invention is a cannula seal assembly. The assembly includes a housing having a primary seal and a secondary seal therein. The assembly has a spacer connected between the primary and secondary seals, and a reservoir between the primary and secondary seals.

[0010] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0011] The present invention will be more fully understood and appreciated from a reading of the following detailed description in conjunction with the accompanying drawings, which illustrate only typical embodiments of the disclosed subject matter and are not intended to limit the scope of the disclosed subject matter, to which other equally effective embodiments may be admitted. Reference will now be made briefly to the accompanying drawings, in which: [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic partial cross-sectional view of a cannula according to one embodiment. [Figure 2] FIG. 1 is an enlarged cross-sectional side schematic view of a screw thread, according to one embodiment. [Figure 3] FIG. 10 is an enlarged cross-sectional side schematic view of a screw thread in a compressed position, according to one embodiment. [Figure 4] FIG. 10 is an enlarged side cross-sectional schematic view of a screw thread in an extended position, according to one embodiment. [Figure 5] FIG. 10 is an enlarged cross-sectional side schematic view of a screw thread according to an alternative embodiment. [Figure 6] FIG. 10 is an enlarged cross-sectional side schematic view of a screw thread according to another alternative embodiment. [Figure 7] FIG. 10 is a partially exploded schematic view of a cannula according to an alternative embodiment. [Figure 8] FIG. 8 is a perspective schematic view of the cannula of FIG. 7. [Figure 9] FIG. 8 is a partial internal view of the distal end of the cannula of FIG. 7. [Figure 10] FIG. 1 is a partial interior side schematic view of a cannula seal assembly, according to one embodiment. [Figure 11] FIG. 2 is a schematic diagram of a partial interior perspective view of a primary seal and a secondary seal, according to one embodiment. [Figure 12] FIG. 1 is a top schematic view of a cannula seal assembly, according to one embodiment. [Figure 13] FIG. 1 is a perspective schematic view of a cannula seal assembly, according to one embodiment. [Figure 14] FIG. 10 is another perspective schematic view of a cannula seal assembly, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Aspects of the present invention and its specific features, advantages, and details are more fully described below with reference to non-limiting examples illustrated in the accompanying drawings. Descriptions of well-known structures are omitted so as not to unnecessarily obscure the details of the invention. It should be understood, however, that the detailed description and specific non-limiting examples, while indicating aspects of the invention, are given by way of illustration only, and not by way of limitation. Various substitutions, modifications, additions, and / or arrangements within the spirit and / or scope of the underlying inventive concept will be apparent to those skilled in the art from this disclosure.

[0014] Referring now to the drawings, wherein like reference numerals refer to like parts throughout, FIG. 1 shows a partial cross-sectional schematic view of a cannula 10, according to one embodiment. Cannula 10 has a proximal end 12 and a distal end 14. Distal end 14 is configured for insertion into a portal at a surgical site. A cannula body 16 extends from proximal end 12 along a central longitudinal axis yy. 2 to a distal end 14. Cannula 10 further includes a port 18 extending from its proximal end 12. Port 18 provides an outlet for fluid flow from cannula 10. Port 18 includes a control valve (not shown) for allowing or preventing fluid flow through port 18. (The control valve extends through a control valve opening 20, as will be understood by those skilled in the art.)

[0015] Cannula body 16 is elongated and tubular, having an open proximal end 22 and an open distal end 24 with an interior volume 26 extending therebetween. Interior volume 26 is sized and configured to accommodate surgical instruments and devices. In the illustrated embodiment, distal end 24 of cannula body 16 is threaded, as shown, with threads 28 extending proximally from distal end 24 along at least a portion of outer surface 30 of cannula body 16. Threads 28 function as a locking mechanism for securing cannula 10 at the surgical site.

[0016] 2, an enlarged schematic side cross-sectional view of thread 28 is shown, according to one embodiment. As shown, thread 28 extends at an angle relative to the central longitudinal axis yy. In particular, threads 28 extend proximally (i.e., toward the proximal end 12 of cannula 10). The profile of threads 28 is angled proximally, away from the direction of insertion. In alternative embodiments, the profile of threads 28 may be angled distally, toward the direction of insertion.

[0017] 3, an enlarged schematic cross-sectional side view of threads 28 in a compressed position is shown, according to one embodiment. As shown, threads 28 are constructed of a flexible material such that threads 28 yield under a predetermined compressive force. In other words, tips 32 of threads 28 extend proximally (toward central longitudinal axis yy) toward outer surface 30 of cannula body 16 in the compressed position. This proximal bending reduces the overall profile of cannula 10 when compressed (i.e., forced proximally by tissue) during insertion. Thus, the reduced profile of threads 28 during insertion minimizes interference.

[0018] Referring now to FIG. 4, an enlarged schematic side cross-sectional view of threads 28 in an expanded position is shown, according to one embodiment. Although threads 28 are flexible, threads 28 must be capable of fixation at the surgical site. As shown in FIG. 4, threads 28 expand under a tensile load (i.e., a distal force) to maximize the overall profile of cannula 10 during use. Thus, during use, the increased profile of threads 28 increases the fixation strength of cannula 10 in tissue at the surgical site. From the compressed position of FIG. 3, tips 32 of threads 28 bend slightly distally back to the expanded position.

[0019] 5 and 6, enlarged cross-sectional side schematic views of a thread 28 are shown according to an alternative embodiment. In the embodiment shown in FIGS. 5 and 6, the geometry of the thread 28 allows for resistance to proximal and distal compression. In FIG. 5, the thread 28 has different radii at the base 34 of the thread 28. Specifically, the thread 28 has a first radius R1 on the distal side 36 of the base 34 and a second radius R2 on the proximal side 38 of the base 34. In the illustrated embodiment, the second radius R2 is smaller than the first radius R1. Because the second radius R2 on the proximal side 38 is smaller, the thread 28 is more susceptible to compression in the proximal direction D1. Similarly, a base 34 having a larger first radius R1 on the distal side 36 is more resistant to compression in the distal direction D2.

[0020] In Figure 6, thread 28 has a reinforced base 34 that resists compression in the distal direction D2. In the illustrated embodiment, thread 28 has a support structure 40, such as a secondary thread, adjacent the distal side 36 of base 34 (or thread 28). In Figure 6, support structure 40 has a triangular shape. . In particular, the support structures 40 are angled so that they become larger (or wider) closer to the threads 28. The angle of the support structures 40 allows the tips 32 of the threads 28 to be compressed in the proximal direction D1 (i.e., not interfere with a force applied in the distal direction D1) and also supports the bases 34 of the threads 28 when a force is applied to the threads 28 in the proximal direction D1. Furthermore, the support structures 40 are small enough that they do not extend past the threads 28 when the threads 28 are in the compressed position.

[0021] The combination of rigidity and flexibility characteristics of cannula 10 can be achieved using a single material or a combination of materials. Cannula 10 of FIG. 1 is constructed from a single material. The combination of rigidity and flexibility characteristics of cannula 10 can be achieved by optimizing the material properties of the substrate and the geometry of cannula 10. In the embodiment of cannula 10 shown in FIG. 1, cannula body 16 has a tube thickness t. Thickness t is large enough that a flexible material can be used to still create a rigid cannula body 16. Similarly, the same material can be used for flexible threads 28 by varying the material thickness. As shown in FIG. 1, threads 28 have a thickness t' that is small enough that threads 28 are flexible. In the illustrated embodiment, thickness t' of threads 28 is less than thickness t of cannula body 16.

[0022] 7 and 8, perspective schematic views of a cannula 10 are shown, according to an alternative embodiment. The cannula 10 shown in FIGS. 7 and 8 is constructed from a combination of materials. In other words, some features of the cannula 10 are constructed from flexible materials, while other features of the cannula 10 are constructed from rigid materials. As shown in FIG. 7, the cannula body 16 is made from or otherwise constructed from a rigid material that provides structural strength for the cannula 10.

[0023] Threads 28, on the other hand, are made or otherwise constructed from a flexible material that provides the necessary flexibility to reduce interference during insertion. In the embodiment shown in Figures 7 and 8, threads 28 are made on a sleeve 42 constructed from a flexible material. Sleeve 42 is cannulated so that sleeve 42 can be slipped over cannula body 16 (i.e., cannula body 16 extends through sleeve 42, as shown in Figure 8). This allows for a combination of materials to achieve the same functionality as cannula 10 of Figure 1.

[0024] Referring briefly to Figure 9, there is shown a partial internal view of the distal end 14 of the cannula 10 of Figures 7 and 8. When the rigid cannula body 16 extends through the flexible sleeve 42, the sleeve 42 extends distally through the distal end 24 of the cannula body 16. This additional length of the sleeve 42 is the compliant tip 44, as shown in Figure 9. The compliant tip 44 protects the surgical site from unintentional injury.

[0025] Referring now to FIG. 10, a partial interior side schematic view of a cannula seal assembly 100 is shown, according to one embodiment. Assembly 100 is sized and configured for attachment to the proximal end 12 of cannula 10 (as shown in FIGS. 1 and 7-9). Assembly 100 includes a housing 102 having two seals positioned therein. The two seals include one or more distal primary seals 104 and a proximal secondary seal 106. As also shown in FIG. 10, a reservoir 108 separates primary seal 104 from secondary seal 106.

[0026] Primary seal 104 is the main seal within assembly 100. Fluid flows from distal end 24 of cannula body 16, through cannula 10, and toward primary seal 104. When primary seal 104 is intact, it provides a barrier that limits the flow of fluid through cannula 10. If primary seal 104 is compromised (e.g., by a surgical instrument), the flow The body passes through the primary seal 104 and into the reservoir 108. As shown in FIG. 10, the reservoir 108 is the space between the primary seal 104 and the secondary seal 106. Any splash leaks that bypass the primary seal 104 are captured by the secondary seal 106. The secondary seal 106 significantly reduces the amount of "splash" experienced by the user. In particular, the secondary seal 106 acts as a splash guard because it cannot withstand fluid pressure but captures any splash leaks.

[0027] Referring now to FIG. 11 , a partial interior perspective schematic view of the primary seal 104 and the secondary seal 106 is shown, according to one embodiment. As shown, separation of the secondary seal 106 and the primary seal 104 is maintained by a spacer 110. The spacer 110 is comprised of circular disks 112A, 112B having a central opening 114 to avoid interference with the reservoir 108. In the embodiment shown in FIG. 11 , the spacer 110 comprises a first circular disk 112A and a second circular disk 112B with one or more connectors 116 extending therebetween. The connectors 116 may be any piece or portion of rigid material that holds the first circular disk 112A at a distance from the second circular disk 112B and forms at least one lateral spacer slot 118 therebetween. The purpose of the spacer slot 118 is to allow fluid to flow out of the reservoir 108.

[0028] During use, the reservoir 108 between the primary seal 104 and the secondary seal 106 fills with fluid. The presence of low pressure fluid in the reservoir 108 provides additional protection against blowout leakage. Excess fluid leaks from the reservoir 108 through one or more transverse external slots 120 in the outer wall 122 of the housing 102 (FIG. 10), preventing fluid buildup between the primary seal 104 and the secondary seal 106. The spacer slots 118 and the external slots 120 are transverse to the longitudinal central axis yy passing through the cannula 10. Specifically, the slots 118, 120 are substantially perpendicular to the longitudinal central axis yy; along an axis xx substantially parallel to the direction of extension of the port 18 (FIG. 10) (i.e. , substantially parallel).

[0029] 12-14, various schematic views of a cannula seal assembly 100 are shown, according to one embodiment. To ensure that the reservoir 108 is consistently filled with fluid to promote leak prevention, the assembly 100 includes one or more chambers 124 extending around the reservoir 108. As shown in FIG. 12, the chambers 124 are concentric and extend at least partially around the reservoir 108. In the illustrated embodiment, the chambers 124 are created between the secondary seal 106 and the housing 102. (Note that the housing 102 has been removed from FIGS. 12-14 for clarity.) The fluid level between the primary seal 104 and the secondary seal 106 rises as fluid flows in through the primary seal 104. Eventually, the fluid exceeds the volume of the reservoir 108 and flows out through the chambers 124.

[0030] As shown in FIGS. 13 and 14 , the assembly 100 also includes one or more channels 126 that extend around the reservoir 108. In the illustrated embodiment, the seals 104, 106 are concentrically surrounded by an inner wall 128. The inner wall 128 has one or more edges 130 extending therealong, such that the edges 130 are between the inner wall 128 and the housing 102. The edges 130 form the channels 126 that extend around the reservoir 108. In the illustrated embodiment, the edges 130 and the resulting channels 126 extend only partially around the reservoir 108. Additionally, the channels 126 shown in FIGS. 13 and 14 are offset from the chamber 124 to ensure that the outflow water level always exceeds the height of the spacer 110.

[0031] Specifically, Figure 12 shows fluid path p from chamber 124. Figure 13 shows fluid path p exiting chamber 124 and entering channel 126. The fluid level must exceed a peak before flowing out of assembly 100. The offset arrangement of chamber 124 and channel 126 in Figure 14 ensures that a consistent fluid layer remains above primary seal 104 within reservoir 108. Finally, the arrangement of spacer 110 and seals 104, 106 allows for priming of reservoir 108 with fluid during the course of use.

[0032] While embodiments of the present invention have been particularly shown and described with reference to certain exemplary embodiments, it will be understood by those skilled in the art that various changes in detail can be made therein without departing from the spirit and scope of the invention as defined by the claims, which may be supported by the written description and drawings. Furthermore, when an exemplary embodiment is described with reference to a particular number of elements, it will be understood that the exemplary embodiment may be implemented utilizing any of the particular number of elements or less.

Claims

1. an elongated, relatively rigid cannula body having a proximal end and a distal end; a sleeve having a reduced stiffness relative to the cannula body, the sleeve extending along at least a portion of the cannula body from the distal end toward the proximal end; a thread extending along at least a portion of the sleeve and having a reduced stiffness relative to the cannula body; A cannula comprising: the stiffness of the threads is set lower than the stiffness of the cannula body to such an extent that the threads contract when a force is applied from the distal end toward the proximal end of the cannula body during insertion of the cannula into the surgical site, and the threads expand when a force is applied from the proximal end toward the distal end of the cannula body with the cannula inserted into the surgical site; The thread has a base portion that connects with the sleeve on the proximal end side of the thread, A cannula, wherein a distal side of the base is contoured in a cross section containing a central longitudinal axis of the cannula body with a first radius of curvature, and a proximal side of the base is contoured in the cross section with a second radius of curvature, the second radius of curvature being smaller than the first radius of curvature.

2. The cannula of claim 1 , wherein the cannula body is constructed from a material having a first thickness and the sleeve is constructed from a material having a second thickness less than the first thickness.

3. The cannula of claim 1 , further comprising a tip of the sleeve extending at least partially beyond the cannula body and having a reduced stiffness relative to the cannula body.

4. An elongated, relatively rigid cannula body having a proximal end and a distal end; a sleeve having a reduced stiffness relative to the cannula body, the sleeve extending along at least a portion of the cannula body from the distal end toward the proximal end; a thread extending along at least a portion of an outer surface of the sleeve and having a reduced stiffness relative to the cannula body; A cannula comprising: the stiffness of the threads is set lower than the stiffness of the cannula body to such an extent that the threads contract when a force is applied from the distal end toward the proximal end of the cannula body during insertion of the cannula into the surgical site, and the threads expand when a force is applied from the proximal end toward the distal end of the cannula body with the cannula inserted into the surgical site; A cannula, wherein the threads include a base portion that connects to the sleeve on the proximal side of the threads, and a support structure adjacent to the distal side of the base and extending from the outer surface of the sleeve to support the distal side of the base.

5. The cannula of claim 4 , wherein the support structure is angled such that its dimension along the radial direction of the sleeve increases as it approaches the distal side of the base.

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