Cannula Assembly

Abstract

Certain embodiments herein disclose a cannula assembly (200). The cannula assembly (200) includes a cannula (210) having a proximal end (214) and a distal end (218). The cannula (210) includes a head (212) at the proximal end (214), the head (212) having one or more wings (236a-c). The cannula (210) also includes a hollow rod (216) extending from the head (212) to the distal end (218). The cannula assembly (200) also includes a hub (250) coupleable to the head (212) and having a housing (252) with an inner wall (259). The inner wall (259) includes an undercut (264), and one or more distal ends (239a-c) of the corresponding one or more wings (236a-c) are configured to fit within the undercut (264) and to couple the hub (250) to the head (212) upon insertion of the head (212) into the hub (250).

Description

[Background technology]

[0001] Surgical instruments may be used by surgeons during various ophthalmic surgeries for manipulation and / or removal of vitreous material, blood, scar tissue, or other objects. A surgeon may use several surgical instruments during an ophthalmic procedure and may need to repeatedly insert and remove these instruments from an incision.

[0002] A cannula assembly, also called a trocar cannula, may be inserted into an incision in the eye. Surgical instruments may then be inserted through the cannula assembly into the incision, with the cannula assembly protecting the side walls of the incision from repeated contact with the instruments. Because the eye is a pressurized sphere during ophthalmic surgery, if special precautions are not taken, such as using a valved cannula assembly, vitreous may be expelled from the cannula assembly when it is inserted into the eye.

[0003] Furthermore, during surgery, it is desirable to allow insertion of the cannula assembly into the eye while preventing leakage of pressurized fluid. Conventionally, as shown in prior art Figures 1A and 1B, the cannula assembly may be provided with a valve to prevent loss of pressurized fluid through the cannula assembly.

[0004] FIG. 1A is a schematic cross-sectional view of an eye 100 during an exemplary ophthalmic procedure, such as a vitrectomy. To insert a cannula assembly 110, the distal end of a trocar blade removably coupled to the cannula assembly 110 creates a microincision in the ocular wall 102, e.g., the pars plana 106. The cannula assembly 110 is then fully inserted through the microincision in the ocular wall 102. After the cannula assembly 110 is inserted, the trocar blade is withdrawn through the microincision in the ocular wall 102, leaving the cannula assembly 110 positioned through the ocular wall 102. The cannula assembly 110 provides an interface for instrument exchange while providing a self-sealing valve for passively controlling fluid and pressure communication from the inside and outside of the eye 100. FIG. 1A shows an example of the cannula assembly 110 inserted into the ocular wall 102 after the trocar blade has been withdrawn.

[0005] FIG. 1B is an isolated, top isometric view of the prior art cannula assembly 110 of FIG. 1A. The cannula assembly 110 includes a cannula 112 having a distal end configured to extend into the eye 100. As described herein, it should be noted that the distal end or distal portion of a component refers to the end or portion that is closer to the patient's body during use of that component. Conversely, the proximal end or proximal portion of a component refers to the end or portion that is farther away from the patient's body. In certain cases, the proximal end of the cannula 112 has a thickness that resists insertion through the fine incision created by the trocar blade, sometimes requiring an undesirably high insertion force to be applied to the cannula 112. A hub 114 is coupled to the proximal end of the cannula 112 and is positioned outside the eye 100 in contact with the outer surface of the ocular wall 102 (shown in FIG. 1A). In certain cases, assembly of the cannula assembly 110 can be difficult. During assembly of cannula assembly 110, clocking of hub 114 is required to properly align hub 114 with cannula 112.

[0006] Valve septum 116 blocks an opening to channel 118 (shown in phantom in FIG. 1B ) of cannula assembly 110. A slit 120 formed through valve septum 116 allows access to channel 118 for regulating fluid and pressure communication to and from eye 100. In certain cases, valve septum 116 has a flat top surface 122 that is flush with top surface 124 of hub 114. A flat valve septum 116 may resist instrument insertion through slit 120, sometimes requiring undesirably high insertion forces to be applied to the instrument. A flat valve septum 116 may also leak if intraocular pressure exceeds environmental pressure. Furthermore, the flat top surface 122 of the valve septum 116, the top surface 122 of the valve septum 116 being at the same level as the top surface 124 of the hub 114, and the translucent appearance of the valve septum 116 sometimes make it difficult to guide an instrument into the center of the valve septum 116, complicating instrument insertion.

[0007] Thus, there is a need for improved devices, systems, and methods that provide an interface for instrument exchange during ophthalmic surgery, and there is a particular need for improved cannula assemblies and methods of use. Summary of the Invention [Means for solving the problem]

[0008] The present disclosure relates generally to cannula assemblies used during surgical procedures, such as ophthalmic procedures.

[0009] Certain embodiments herein disclose a cannula assembly. The cannula assembly includes a cannula having a proximal end and a distal end. The cannula includes a head at the proximal end, the head having one or more wings. The cannula also includes a hollow rod extending from the head to the distal end. The cannula assembly also includes a hub coupleable to the head and having a housing with an inner wall. The inner wall includes an undercut, and one or more distal ends of the one or more corresponding wings are configured to fit within the undercut and couple the hub to the head upon insertion of the head into the hub.

[0010] The drawings described herein are for illustrative purposes only and are schematic in nature and are intended to be exemplary rather than limiting the scope of the present disclosure. [Brief explanation of the drawings]

[0011] [Figure 1A-1B] Figure 1A is a prior art schematic cross-sectional view of an eye during an exemplary ophthalmic surgery. Figure 2B is an isolated top isometric view of the cannula assembly of Figure 1A. [Figure 2A] FIG. 2A is a diagram of an exemplary assembled fenestrated cannula assembly, according to certain embodiments of the present disclosure. [Figure 2B] 2B is an exploded view of the exemplary fenestrated cannula assembly of FIG. 2A, in accordance with certain embodiments of the present disclosure. [Figure 2C] FIG. 2C is a cross-sectional view of the assembled fenestrated cannula assembly of FIGS. 2A-2B, in accordance with a specific embodiment of the present disclosure. [Figure 3A] FIG. 3A is a diagram of a fenestrated hub of a fenestrated cannula assembly, in accordance with a specific embodiment of the present disclosure. [Figure 3B] 3B is a cross-sectional view of the fenestrated hub of the fenestrated cannula assembly of FIG. 3A, in accordance with a specific embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] The above summary is not intended to represent all possible embodiments or every aspect of the present disclosure. Rather, the foregoing summary is intended to illustrate some of the novel aspects and features disclosed herein. The above-mentioned features and advantages, as well as other features and advantages of the present disclosure, will be readily apparent from the following detailed description of exemplary embodiments and best modes for carrying out the present disclosure, when read in conjunction with the accompanying drawings and the appended claims.

[0013] Embodiments disclosed herein provide a cannula assembly for instrument exchange during ophthalmic surgery. In certain embodiments, the disclosed cannula assembly includes a hub, which may be fenestrated, and a cannula. In certain embodiments, the hub includes a groove or undercut (e.g., an annular undercut) that allows the cannula to be press-fit into the hub without precisely aligning the hub with the cannula. In certain embodiments, the hub includes a relief cutout configured to prevent cracking when the housing of the hub is subjected to high pressures. The relief cutout may also function to disrupt material flow during injection molding of the housing, thereby reducing the likelihood of separate flows converging, causing instability or weakness in the housing.

[0014] 2A-2B are assembled and disassembled top isometric views, respectively, of an exemplary fenestrated cannula assembly 200. FIG. 2C is a cross-sectional view of the assembled fenestrated cannula assembly 200 of FIGS. 2A-2B. Therefore, for clarity, FIGS. 2A-2C are described together herein.

[0015] Fenestrated cannula assembly 200 generally includes a cannula 210 and a fenestrated valved hub (fenestrated hub) 250 coupled or coupleable to cannula 210. Cannula 210 includes a cannula head (head) 212 at a proximal end 214 of cannula 210 and a hollow rod 216 extending from head 212 to a distal end 218 of cannula 210. Together, head 212 and hollow rod 216 form a working channel 220 through which various instruments may be inserted into the eye during surgery. Head 212 has a tapered inner diameter that tapers downward to match the smaller inner diameter of hollow rod 216, for example, to help guide instruments into hollow rod 216.

[0016] The wall 226 of the hollow rod 216 has an inner surface 224 that surrounds the channel 220. The thickness of the wall 226 is measured radially from the inner surface 224 to the outer surface 228 of the wall 226. The hollow rod 216 has a thin-wall section 230 at the distal end 218. The thin-wall section 230 may be thinner than the distal end of a conventional cannula. Thus, the thin-wall section 230 reduces the insertion force required to insert the cannula 210 through the wall 102 of the eye, thereby reducing the potential for damage to the wall 102 of the eye.

[0017] In the example of FIG. 2B, a plurality of wings 236 extend radially outward from head 212. While head 212 includes four wings 236 in FIG. 2B, fewer or more than four wings are also within the scope of this disclosure. An isometric view of wings 236a-236c is shown in FIG. 2B, while a cross-sectional view of wings 236a and 236b is shown in FIG. 2C. As shown, each wing 236 has a tip or distal end 239 (e.g., distal ends 239a-239c) configured to be received within and secured by an internal undercut 264 in an inner wall 259 of housing 252 of windowless hub 250. For example, as described further below, when assembling the fenestrated cannula assembly 200, the head 212 is placed inside the fenestrated hub 250 and the wings 236 are press-fit into the undercuts 264 to couple the fenestrated hub 250 to the head 212.

[0018] Fenestrated hub 250 generally includes a housing 252 and a valve 270. When fenestrated cannula assembly 200 is assembled, housing 252 radially and at least partially surrounds head 212 of cannula 210. Housing 252 has a fenestrated, solid sidewall 258 having a generally cylindrical shape. In particular, sidewall 258 includes a cylindrical portion making up the majority of the sidewall, and a flat or planar portion 263. Flat portion 263 may provide a starting point or reference point during manufacturing and shaping of housing 252 and assembly of fenestrated cannula assembly 200. In particular, flat portion 263 may enable a manufacturing system to automatically identify the orientation of fenestrated cannula assembly 200 during manufacturing. Flat portion 263 also provides a reference point for the manufacturing system when aligning fenestrated hub 250 with cannula 210. Additionally, flat portion 263 provides a reference point for the cylindrical shape of windowless hub 250 in an otherwise convenient manner, preventing windowless hub 250 from rotating in a nested or telescoping arrangement during manufacturing.

[0019] Housing 252 has an opening 260 at the bottom for receiving head 212 of cannula 210 and a smaller opening at top 254 for receiving valve 270. Note that a fenestrated cannula assembly refers to a cannula assembly having a solid housing 252 without any openings or windows in sidewall 258. In other words, in the embodiment shown in FIGS. 2A-3B , housing 252 has only two openings: bottom opening 260 and a top opening for receiving valve 270. Housing 252 does not have any openings on sidewall 258. However, in certain other embodiments, sidewall 258 may have one or more openings. In certain embodiments, housing 252 is formed by injection molding. In certain embodiments, housing 252 comprises a rigid polymer or plastic material, such as polycarbonate or polypropylene. In certain embodiments, housing 252 may include one or more relief cutouts 265. The one or more relief cutouts 265 may be positioned at various angles and may be of various sizes.

[0020] In the example of FIGS. 2A-3B , the windowless hub 250 includes two equally spaced or symmetrically positioned relief cutouts 265 in the bottom 294 of the windowless sidewall 258. However, generally, fewer or more relief cutouts 265 may be provided. The relief cutouts 265 are configured to prevent cracking when the housing 252 is subjected to high pressures. The relief cutouts 265 may also function to disrupt the flow of material during injection molding, thereby reducing the likelihood of separate flows converging, causing instability or weakness in the housing 252. For example, by including the relief cutouts 265 in areas that exhibit weakness or are prone to cracking (also called stress points), the relief cutouts 265 alter the flow of material during injection molding, ensuring that the fronts of the material flows meet at points on the housing 252 that are not inherently weak or prone to cracking. In some embodiments, the stress points may be, for example, at the bottom of a curved side of the windowless hub 250.

[0021] As discussed, in the example of Figures 2A-3B, the windowless hub 250 includes two relief cutouts 265, one of which is shown in Figures 2A-2B and 3A. In Figures 2C and 3C, cross-sectional views of both relief cutouts 265a-265b are shown. In some other embodiments, the windowless hub 250 includes four relief cutouts, which may be equally spaced or symmetrically spaced. Those skilled in the art will appreciate that the illustrated arrangements are only some of the various arrangements of cutouts suitable for improving strength, reducing problematic material flow, or providing relief from structural stresses, and that the cutouts may be differently sized, shaped, numbered, or configured without departing from the scope of the present disclosure.

[0022] 2C and 3C, an annular (e.g., 360-degree) internal groove or undercut 264 is provided in the inner wall 259 of the housing 252. When the undercut 264 is provided, the thickness of the sidewall 258 is reduced compared to other portions of the sidewall 258. Note that having a solid, windowless sidewall 259 (e.g., without any openings) allows for the annular undercut 264 to be provided. However, in certain embodiments, the annular undercut 264 may be provided even if some openings are present in the sidewall 259, provided that there are openings in the sidewall 259 above or below the location where the undercut 264 is provided.

[0023] In certain embodiments, the shape of undercut 264 matches the shape of distal end 239 of wing 236, such that press-fitting cannula 210 into fenestrated hub 250 results in distal end 239 fitting snugly within undercut 264. For example, undercut 264 includes at least two side surfaces 266 and 267 and a circular center portion between side surfaces 266 and 267. Side surface 266 is disposed at an angle relative to the longitudinal axis of cannula 210 that may be the same as or substantially similar to the angle at which wings 236 extend from head 212. Side surface 267 is also formed at an angle relative to the longitudinal axis of cannula 210 that allows distal end 239 to abut against side surface 267 and securely couple head 212 to fenestrated hub 250. Once cannula 210 is press-fit into fenestrated hub 250, any force exerted to separate the two parts will cause side surfaces 267 to exert an opposing force on distal ends 239 of wings 236, thereby preventing cannula 210 from separating from fenestrated hub 250. Annular undercut 264 allows head 212 of cannula 210 to be press-fit into fenestrated hub 250 without having to clock fenestrated hub 250 to precisely align hub 250 with cannula 210. In certain embodiments, undercut 264 may not be annular. In other words, certain portions of inner wall 259 may provide an undercut, while other portions may be solid (i.e., not have any reduced thickness).

[0024] Valve 270 is disposed in housing 252. Valve 270 has a cylindrical body with a top flange 272. The shape of valve 270 matches the profile of top 254 of housing 252 (including the shape of opening 260). Valve 270 has a septum 276 that is concave relative to top surface 256 of top 254. Septum 276 is configured to provide an opening 280 for an instrument. The concave septum 276 reduces the insertion force required to insert an instrument through opening 280, thereby making instrument insertion easier. The concave septum 276 also serves to physically guide the instrument into opening 280, which is centered in septum 276, making instrument insertion easier.

[0025] Top surface 282 of septum 276 is recessed a distance 284 from top surface 256 of housing 252. This recessed distance 284 is measured along the longitudinal axis of cannula 210 from top surface 256 of housing 252 at the radial center of septum 276 to top surface 282 of septum 276. Distance 284 may be about 0.005 inches or greater, e.g., from about 0.005 inches to about 0.02 inches, e.g., about 0.01 inches. In contrast to conventional hubs in which the septum is flush with the top surface, the recessed septum 276 of windowless hub 250 helps to physically guide an instrument into central opening 280 of septum 276, making instrument insertion easier.

[0026] In some embodiments, a ridge 296 may extend a distance 290 from the top of the perimeter of the opening 280 to further facilitate instrument insertion. In certain embodiments, valve 270 comprises a resilient polymer, such as silicone. The material of valve 270 is selected to help maintain intraocular pressure between about 10 mmHg (millimeters of mercury) and about 25 mmHg. In certain embodiments, valve 270 is overmolded onto housing 252. In some other embodiments, valve 270 is formed separately and then bonded together with housing 252.

[0027] When fenestrated cannula assembly 200 is assembled, an annular seal 292 that contacts top surface 238 of head 212 is provided to provide a gas- and fluid-tight seal between cannula 310 and fenestrated hub 250. In the example of Figures 2A-2C, seal 292 is integral with valve 270. In some other embodiments, seal 292 may be formed separately from valve 270 and overmolded or bonded onto housing 252.

[0028] In certain embodiments, the color of housing 252 is different from the color of valve 270 to provide a visual contrast between housing 252 and valve 270. For example, housing 252 may be uncolored, e.g., the color of natural polycarbonate, while valve 270 may be colored. In certain embodiments, housing 252 may have a more translucent appearance than valve 270. Compared to conventional hubs with translucent septa, the visual contrast provided by the color of valve 270 helps provide a visual guide to central opening 280 of septum 276, making instrument insertion easier.

[0029] Figures 3A-3B are additional exemplary views of the windowless hub 250 described in connection with Figures 2A-2C. Figures 3A-3B are a top isometric view and a cross-sectional view, respectively, of the windowless hub 250.

Claims

1. 1. A cannula assembly comprising: A cannula having a proximal end and a distal end, a head at the proximal end having one or more wings; a hollow rod extending from the head to the distal end; a cannula including: a hub connectable to the head and having a housing with an inner wall; Preparation, the inner wall includes an undercut; one or more distal ends of the corresponding one or more wings are configured to fit within the undercut to couple the hub to the head upon insertion of the head into the hub; Cannula assembly.

2. The cannula assembly according to claim 1 , wherein the housing of the hub includes one or more relief cutouts.

3. The cannula assembly of claim 2, wherein the one or more relief cutouts include two to four cutouts located on a bottom of the housing.

4. The cannula assembly of claim 3, wherein the two to four cutouts are equally spaced apart on the bottom of the housing.

5. The cannula assembly of claim 1 , wherein the hub includes a septum that is recessed relative to the top of the hub.

6. 2. The cannula assembly of claim 1, wherein the wall of the cannula has a first thickness at the distal end and a second thickness at one or more other portions of the cannula, the first thickness being different from the second thickness.

7. The hub is a housing having a first color; a valve disposed in the housing having a second color different from the first color; The cannula assembly of claim 1 , comprising:

8. The cannula assembly of claim 1 , wherein the hub includes a solid, fenestrated sidewall.

9. The cannula assembly of claim 1 , wherein the hub includes a sidewall having a planar portion and a cylindrical portion.

10. The cannula assembly of claim 1 , wherein the hub is fenestrated.

11. The cannula assembly of claim 1 , wherein the one or more distal ends of the corresponding one or more wings are configured to fit within the undercut when the head is inserted into the hub in any orientation.

12. The cannula assembly of claim 1 , wherein the shape of the undercut is configured to match the shape of the one or more distal ends of the corresponding one or more wings.

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