Ophthalmic treatment cannula

Abstract

Certain aspects of the present disclosure relate generally to ophthalmic surgery, and more particularly to methods and devices for controlling intraocular pressure (IOP). An exemplary device generally includes a proximal segment including a first inner diameter (ID), a middle segment connected to the proximal segment, the middle segment including a second ID smaller than the first ID, and a distal segment connected to the middle segment, the distal segment including a third ID smaller than the second ID.

Description

[Background technology]

[0001] Posterior segment surgery is performed to treat conditions of the ocular fundus such as age-related macular degeneration (AMD), diabetic retinopathy and diabetic vitreous hemorrhage, macular hole, retinal detachment, epimacular membrane, and cytomegalovirus (CMV) retinitis.

[0002] Certain problems affecting the fundus may require a vitrectomy, i.e., the surgical removal of the vitreous, a typically clear, gel-like substance that fills the center of the eye and helps give it shape. For example, a vitrectomy may be performed to remove blood and floaters from the eye, remove scar tissue, or relieve tension on the retina. During this procedure, three separate incisions are made in the pars plana of the eye, just posterior to the iris and anterior to the retina. These incisions are used to pass instruments, such as light pipes, irrigation ports, and / or vitrectomy cutters, into the eye. A valved cannula is positioned within each incision to provide a self-sealing valve that passively controls fluid and pressure communication between the interior and exterior of the eye via the cannula while allowing instruments to access the interior of the eye via the cannula.

[0003] When vitreous humor is aspirated during posterior segment surgery, intraocular pressure (IOP) decreases, tending to soften the patient's eye. To maintain IOP and avoid deformation or collapse of the eye, an irrigation cannula may be connected to the valved cannula to irrigate the eye with a fluid, such as a liquid or gas (e.g., balanced saline solution (BSS)). Additionally, maintaining IOP can help maintain scleral rigidity to facilitate eye movement and instrument exchanges during the procedure. However, prolonged high IOP can damage ocular structures, so IOP must be carefully regulated. If the IOP becomes too high, another irrigation cannula can be used to drain fluid from the eye and reduce pressure.

[0004] Some existing fluid cannulas (e.g., irrigation cannulas, etc.) have drawbacks. For example, some existing fluid cannulas are individually sized, i.e., each fluid cannula has dimensions that are tailored to the specific gauge of the valved cannula to which it is to be connected. Valved cannulas (also called valved trocar cannulas) are available in several gauges (e.g., 23 gauge, 25 gauge, 27 gauge), and therefore, a user (e.g., an ophthalmic surgeon) must have access to a fluid cannula sized specifically to the gauge of the valved cannula desired for a surgical procedure. The use of different sized valved cannulas further inconveniences the procedure.

[0005] Additionally, certain existing fluid cannula designs result in relatively high fluid friction for the fluid passing therethrough. High fluid friction restricts overall fluid flow and requires higher pressures to maintain that fluid flow rate. Operation at higher pressures may require larger pumps and may result in greater wear and tear on the device. In certain cases, the limitations of conventional tubing sets and viscous fluid delivery systems at high pressures may result in rupture failure and subsequent disconnection. Furthermore, operation at lower pressures minimizes the risk of harm to ocular tissue. Summary of the Invention [Means for solving the problem]

[0006] The present disclosure relates generally to devices, systems, and methods for controlling intraocular pressure during ophthalmic surgery, such as surgical procedures on the posterior segment of the eye, including vitrectomy. More specifically, certain aspects of the disclosure relate to irrigation cannulas for the irrigation / drainage of intraocular fluids and methods of use thereof.

[0007] Certain embodiments provide a cannula device for surgical procedures, the cannula device including: a proximal segment including a first length and a first inner diameter (ID); an intermediate segment connected to the proximal segment, the intermediate segment having a second length and a second ID smaller than the first ID; and a distal segment connected to the intermediate segment, the distal segment having a third length greater than the second length and a third ID smaller than the second ID.

[0008] Certain embodiments provide a cannula device for surgical procedures, the cannula device including: a proximal segment including a first inner diameter (ID), a first length, a first proximal end, and a first distal end; an intermediate segment connected to the proximal segment, the intermediate segment including a second ID smaller than the first ID, a second length, a second proximal end, and a second distal end; a first transition section connecting the proximal and intermediate segments via the first distal end and the second proximal end, the first transition section including a first fillet and a second fillet; a distal segment connected to the intermediate segment, the distal segment including a third ID smaller than the second ID, a third length greater than the second length, a third proximal end, and a third distal end; and a second transition section connecting the intermediate and distal segments via the second distal end and the third proximal end, the second transition section including a third fillet and a fourth fillet.

[0009] The following description and the related drawings set forth in detail certain illustrative features of the one or more embodiments.

[0010] The accompanying drawings depict certain aspects of one or more embodiments and, therefore, should not be considered as limiting the scope of the present disclosure. The figures disclosed herein may not be to scale. [Brief explanation of the drawings]

[0011] [Figure 1A-1B]1A shows a schematic view of an exemplary perfusion cannula assembly including a perfusion cannula according to certain embodiments of the present disclosure, and FIG. 1B shows an enlarged schematic view of the distal end of the perfusion cannula assembly of FIG. 1A according to certain embodiments of the present disclosure. [Figure 2A] 1 shows a perspective view of a perfusion cannula according to a specific embodiment of the present disclosure. [Figure 2B] 2B shows a side cross-sectional view of the exemplary perfusion cannula of FIG. 2A, in accordance with certain embodiments of the present disclosure. [Figure 2C] 2B shows a perspective view of the perfusion cannula of FIG. 2A coupled to a valved cannula, in accordance with certain embodiments of the present disclosure. [Figure 2D] 2D shows a cross-sectional side view of a perfusion cannula coupled to the valved cannula of FIG. 2C in accordance with certain embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] To facilitate understanding, the same reference numerals will be used, wherever possible, to designate identical elements that are common between the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0013] In the following description, details are set forth as examples to facilitate understanding of the disclosed subject matter. However, it should be apparent to those skilled in the art that the disclosed implementations are illustrative and do not encompass all possible implementations. Therefore, it should be understood that reference to the described examples is not intended to limit the scope of the present disclosure. Any changes and further modifications to the described devices, apparatuses, and methods, and any further applications of the principles of the present disclosure, are fully contemplated as would normally occur to one skilled in the art to which the present disclosure pertains. In particular, it is fully contemplated that features, components, and / or steps described with respect to one implementation can be combined with features, components, and / or steps described with respect to other implementations of the present disclosure.

[0014] It should be noted that, as used herein, a distal end, distal segment, or distal portion of a component refers to the end, segment, or portion of that component that is closer to the patient's body during use, while a proximal end, proximal segment, or proximal portion of a component refers to the end, segment, or portion that is farther away from the patient's body, and an intermediate segment or intermediate portion of a component refers to the segment or portion located between the distal segment or distal portion and the proximal end or proximal portion.

[0015] As used herein, the term "about" may refer to a ±10% variation from the nominal value. It is understood that such a variation may be included in any value provided herein.

[0016] Embodiments of the present disclosure provide devices, systems, and methods for controlling intraocular pressure (IOP) and / or administering fluid to the ocular space. For example, embodiments described herein disclose irrigation cannulas and methods of use thereof for irrigating and / or draining intraocular fluids, as described in more detail below. As described herein, irrigation cannulas are coupled to or used with valved cannulas, although it should be noted that in certain aspects, unvalved cannulas may be used rather than valved cannulas. It should also be noted that, while described with respect to vitreoretinal procedures, the devices, systems, and methods described herein are also applicable to other types of cannulas or uses and are not limited solely to ophthalmic procedures. Furthermore, the techniques and designs described herein may be applicable to other types of fluid cannulas as well.

[0017] Some existing fluid cannulas, including irrigation cannulas, include internal diameters (IDs) that can restrict fluid flow to levels lower than those accommodated by a companion valved cannula. For example, the minimum ID of a particular fluid cannula is smaller than the corresponding minimum ID of the valved cannula through which the fluid flows. The minimum ID of a fluid cannula restricts fluid flow because the resistance to fluid flow (R) is directly proportional to the viscosity of the fluid (η) and the length of the passageway (L) through which the fluid flows, the portion of the fluid cannula having a given ID. Furthermore, the resistance to fluid flow is proportional to the fourth power of the radius of the fluid passageway (r 4 ), which is one-half the ID of the fluid passage. Therefore, the resistance to fluid flow is also inversely proportional to the ID of the fluid passage:

number

[0018] Thus, because some existing fluid cannulas include segments with IDs that are smaller than the minimum ID of the corresponding valved cannula, these segments of such existing fluid cannulas restrict fluid flow to levels lower than the valved cannula can actually accommodate.

[0019] As such, certain embodiments described herein provide fluid cannulas that may have one or more of the following features, each of which provides advantages.

[0020] For example, certain embodiments herein provide perfusion cannulas having a distal segment that is shorter in length than some existing fluid cannulas. A shorter distal segment length reduces resistance to fluid flow because resistance is proportional to the length of the fluid passageway.

[0021] Additionally, certain embodiments herein provide a perfusion cannula having an intermediate segment for transitioning between the proximal and distal segments. The intermediate segment can have a larger ID and a longer length than those of some existing fluid cannulas. The larger the ID of the intermediate segment, the lower the resistance to fluid flow as the fluid pathway transitions from the proximal segment to the intermediate segment. In addition, the larger the ID of the intermediate segment, the larger the diameter (inversely proportional to resistance) of the longer portion within the matching valved cannula, thereby lowering the resistance to fluid flow. The longer length of the intermediate segment allows the fluid to flow a longer length / distance before transitioning to the distal segment, which has the smallest ID of the three segments, thereby lowering the resistance to fluid flow.

[0022] Additionally, certain embodiments herein provide perfusion cannulas having transitions between segments with at least two fillets (e.g., round, curved, cutout, radial, spline, or similar curvature) and / or chamfers (e.g., beveled). The transitions provide a smooth transition between the segments. As such, the aforementioned features are configured to reduce the overall flow resistance and pressure drop through the perfusion cannula, thereby lowering the pressure required to maintain a given fluid flow rate, or, stated differently, increasing the flow rate at a given source pressure, as described in more detail below.

[0023] 1A shows a schematic diagram of an exemplary irrigation cannula assembly 100, according to certain embodiments. The irrigation cannula assembly 100 generally includes an irrigation cannula 102, irrigation tubing 190, and an adapter 192. The irrigation cannula 102 can be configured to be inserted into, for example, a valved cannula (shown in FIGS. 2C and 2D) and used to move fluid through the valved cannula and into the ocular space of a patient's eye.

[0024] In certain embodiments, perfusion tubing 190 may include two or more sections of tubing connected by one or more connectors. As shown in FIG. 1A , perfusion tubing 190 includes first (e.g., proximal) perfusion tubing 190A and second (e.g., distal) perfusion tubing 190B connected by connector 194. In certain embodiments, proximal perfusion tubing 190A and distal perfusion tubing 190B may be the same type of tubing. In certain embodiments, proximal perfusion tubing 190A and distal perfusion tubing 190B may be different types of tubing having different characteristics. For example, in certain embodiments, proximal perfusion tubing 190A may comprise a plastic or polymer material, while distal perfusion tubing 190B may comprise a metallic material. In certain embodiments, proximal perfusion tubing 190A and distal perfusion tubing 190B may have different wall thicknesses and / or different outer diameters. In certain embodiments, the proximal end perfusion tube 190A and the distal end perfusion tube 190B may have the same inner diameter while also having different wall thicknesses.

[0025] Irrigation tubing 190 includes a fluid line that is fluidly connected to irrigation cannula 102 at a distal end 196 of irrigation cannula assembly 100. Irrigation tubing 190 also fluidly connects irrigation cannula 102 to a fluid source through an adapter 192 at its proximal end 198 opposite irrigation cannula 102.

[0026] In certain embodiments, the fluid source may include components of a fluid drive system, such as a fluid drive system of a surgical console. During a surgical procedure, fluid stored in the fluid source may flow through the irrigation cannula assembly 100 and the valved cannula into the patient's eye. In such embodiments, the fluid drive system and / or surgical console may be configured to control or drive the flow of fluid at a set pressure and / or flow rate through the irrigation tubing 190 and / or the irrigation cannula 102 based on input from the surgeon to control the IOP of the eye. In such embodiments, the pressure and / or flow rate may be adjusted by the surgeon via operation of a foot pedal or other mechanical or digital switch in communication with the fluid drive system and / or the surgical console.

[0027] 1B shows an enlarged view of the distal end 196 of the perfusion cannula assembly 100, including the perfusion cannula 102. In particular, FIG. 1B shows a side view of the perfusion cannula 102 inserted into the perfusion tubing 190.

[0028] As shown, the perfusion cannula 102 is connected to the perfusion tubing 190, which may be made of the same or a different material. In certain embodiments, the perfusion cannula 102 may be made of any of a variety of materials, including metallic materials (e.g., stainless steel, carbon steel, titanium, or any suitable metal alloy), plastic materials, rigid polymeric materials (e.g., polycarbonate, polyethylene, polypropylene, polyimide), etc. In certain embodiments, the perfusion cannula 102 includes a protective coating, e.g., nickel plating, formed thereon to resist corrosion and / or microbial growth. In certain embodiments, the perfusion tubing 190 may be made of any of a variety of materials, including thermoplastic elastomer materials, etc.

[0029] The irrigation cannula 102 and the irrigation tubing 190 may be manufactured using similar or different manufacturing processes. In certain embodiments, the irrigation cannula 102 may be manufactured using a deep drawing process or a machining process. In certain embodiments, the irrigation tubing 190 may be manufactured using an injection molding process or an injection overmolding process. In certain embodiments, either or both of the irrigation cannula 102 and the irrigation tubing 190 may be manufactured using three-dimensional (3D) printing. In certain embodiments in which the irrigation cannula 102 and the irrigation tubing 190 are manufactured separately, the irrigation cannula 102 and the irrigation tubing 190 may be mechanically connected, for example, via mating slots or tabs and / or frictional forces, or the irrigation cannula 102 and the irrigation tubing 190 may be attached using adhesive or thermal bonding.

[0030] FIG. 2A shows a perspective view of an exemplary perfusion cannula 200 in accordance with certain embodiments of the present disclosure. In particular, FIG. 2A shows the outer contour and certain exterior features of the perfusion cannula 200. FIG. 2B shows a side cross-sectional view of the perfusion cannula 200 of FIG. 2A in accordance with certain embodiments of the present disclosure. In particular, FIG. 2B shows the inner contour and certain interior features of the perfusion cannula 200, and further includes several exemplary dimensions, which are shown in inches unless otherwise noted. In one exemplary embodiment, the perfusion cannula 200 may correspond to the perfusion cannula 102 of FIGS. 1A and 1B.

[0031] As shown, perfusion cannula 200 includes a proximal segment 202, an intermediate segment 214, and a distal segment 204. Proximal segment 202 includes a first proximal end 203A and a first distal end 203B, intermediate segment 214 includes a second proximal end 215A and a second distal end 215B, and distal segment 204 includes a third proximal end 205A and a third distal end 205B. A first transition section 206 connects proximal segment 202 and intermediate segment 214 at first distal end 203B and second proximal end 215A. A second transition section 207 connects intermediate segment 214 and distal segment 204 at second distal end 215B and third proximal end 205A. A third transition portion 208 is configured at the first proximal end 203A to facilitate connection between the proximal segment 202 and a tubing of a perfusion line (eg, the perfusion tubing 190 of FIGS. 1A and 1B).

[0032] In certain embodiments, third transition portion 208 can have a length 249. In certain embodiments, length 249 of third transition portion 208 is between about 0.0247 inches (about 0.6261 mm (millimeters)) and about 0.0334 inches (about 0.8471 mm), such as between about 0.0261 inches (about 0.6629 mm) and about 0.0319 inches (about 0.8103 mm), such as about 0.029 inches (about 0.7366 mm). In certain embodiments, perfusion cannula 200 may not include third transition portion 208. In such embodiments, the overall length of perfusion cannula 200 extends from first proximal end 203A to third distal end 205B of distal segment 204. In certain embodiments, the length 249 of the third transition portion 208 may be greater than or less than 0.029 inches (0.7366 mm).

[0033] As shown, proximal segment 202 has a first ID 240 and a first length 234, intermediate segment 214 has a second ID 248 and a second length 235, and distal segment 204 has a third ID 242 and a third length 236. In certain embodiments, proximal segment 202, intermediate segment 214, and distal segment 204 can each have a substantially uniform diameter along their respective lengths 234, 235, and 236.

[0034] In certain embodiments, the proximal segment 202 has an interior dimension, e.g., a first ID 240. In certain embodiments, the first ID 240 is between about 0.0723 inches (about 1.8352 mm) and about 0.0978 inches (about 2.4829 mm), e.g., between about 0.0765 inches (about 1.9431 mm) and about 0.0935 inches (about 2.3749 mm), e.g., about 0.085 inches (about 2.159 mm). In some embodiments, the first ID 240 of the proximal segment 202 is greater than 0.085 inches (2.159 mm), e.g., if the exterior of the proximal segment 202 fits inside the tubing of a perfusion line (e.g., the perfusion tubing 190 of FIG. 1). In other embodiments, the first ID 240 of the proximal segment 202 may be less than 0.085 inches (2.159 mm).

[0035] In certain embodiments, the intermediate segment 214 has an inner dimension, e.g., a second ID 248. In certain embodiments, the second ID 248 is between about 0.0247 inches (about 0.6261 mm) and about 0.0334 inches (about 0.8471 mm), e.g., between about 0.0261 inches (about 0.6629 mm) and about 0.0319 inches (about 0.8103 mm), e.g., about 0.029 inches (about 0.7366 mm). In certain embodiments, the second ID 248 of the intermediate segment 214 is greater than half the first ID 240 of the proximal segment 202. In certain embodiments, for example, if the exterior of intermediate segment 214 mates with a valved cannula hub (e.g., hub 226 in FIG. 2D ) and / or cannula transition (e.g., cannula transition 230 in FIG. 2D ) or if distal segment 204 has a recess, second ID 248 of intermediate segment 214 is greater than 0.029 inches (0.7366 mm). In other embodiments, second ID 248 of intermediate segment 214 may be less than 0.029 inches (0.7366 mm).

[0036] In certain embodiments, the distal segment 204 has an inner dimension, e.g., third ID 242, that is about 0.0151 inches (about 0.3835 mm) to about 0.0155 inches (about 0.3937 mm), e.g., about 0.0153 inches (about 0.3886 mm) (e.g., about 27 gauge). In certain embodiments, third ID 242 can be about 0.0191 inches (about 0.4851 mm) to about 0.0195 inches (about 0.4953 mm), e.g., about 0.0193 inches (about 0.4902 mm) (e.g., about 25 gauge). In certain embodiments, third ID 242 can be about 0.0240 inches (about 0.6096 mm) to about 0.0244 inches (about 0.6198 mm), such as about 0.0242 inches (about 0.6147 mm) (e.g., about 23 gauge). In certain embodiments, the interior dimension of distal segment 204 is greater than 0.0244 inches (0.6198 mm), for example, when the exterior of distal segment 204 fits inside a valved cannula hub (e.g., shaft 228 in FIG. 2D ) and / or cannula transition (e.g., cannula transition 230 in FIG. 2D ) or when distal segment 204 has a recess.

[0037] In certain embodiments, the overall width 247 of the perfusion cannula 200 can be about 0.0765 inches (about 1.9431 mm) to about 0.1035 inches (about 2.6289 mm), e.g., about 0.081 inches (about 2.0574 mm) to about 0.099 inches (about 2.5146 mm), e.g., about 0.09 inches (about 2.286 mm) in diameter. In certain embodiments, the overall width 247 of the perfusion cannula 200 can be greater or less than 0.09 inches (2.286 mm).

[0038] Generally, segments 202, 204, and 214 and transition portions 206, 207, and 208 share a common central axis 212 disposed through a common center of perfusion cannula 200, which may be formed from a single, unitary body. While described with segments 202, 204, and 214 and transition portions 206, 207, and 208, it should be noted that perfusion cannula 200 may be formed from a single, unitary body, and segments 202, 204, and 214 and transition portions 206, 207, and 208 may refer to portions of the unitary body.

[0039] In certain embodiments, proximal segment 202 has a first length 234, intermediate segment 214 has a second length 235, and distal segment 204 has a third length 236, each measured along central axis 212. Second length 235 may be greater than, less than, or equal to first length 234. Third length 236 may be greater than, less than, or equal to second length 235. In further embodiments, third length 236 is substantially less than (or shorter than) second length 235. In further embodiments, third length 236 is substantially zero, and the overall length of perfusion cannula 200 extends between the distal end of third transition portion 208 and second transition portion 207 (e.g., perfusion cannula 200 does not include distal segment 204).

[0040] In certain embodiments, the first length 234 of the proximal segment 202 is between about 0.1496 inches (about 3.7998 mm) and about 0.2024 inches (about 5.1410 mm), e.g., between about 0.1584 inches (about 4.0234 mm) and about 0.1936 inches (about 4.9174 mm), e.g., about 0.176 inches (about 4.4704 mm). In certain embodiments, the first length 234 of the proximal segment 202 is greater than 0.176 inches (4.4704 mm), for example, if the outside of the proximal segment 202 fits inside the tubing of a perfusion line (e.g., the perfusion tubing 190 of FIG. 1). In other embodiments, the first length 234 of the proximal segment 202 may be less than 0.176 inches (4.4704 mm).

[0041] In certain embodiments, second length 235 of intermediate segment 214 is between about 0.034 inches (about 0.8636 mm) and about 0.046 inches (about 1.1684 mm), e.g., between about 0.036 inches (about 0.9144 mm) and about 0.044 inches (about 1.1176 mm), e.g., about 0.04 inches (about 1.016 mm). In certain embodiments, second length 235 of intermediate segment 214 is greater than 0.04 inches (1.016 mm), for example, when the outside of intermediate segment 214 fits inside a valved cannula hub (e.g., hub 226 in FIG. 2D ) and / or cannula transition (e.g., cannula transition 230 in FIG. 2D ) or when distal segment 204 has a recess. In other embodiments, second length 235 of intermediate segment 214 may be less than 0.04 inches (1.016 mm).

[0042] In certain embodiments, second ID 248 and second length 235 are larger than those of certain existing fluid cannulas. The larger ID of intermediate segment 214 reduces resistance to fluid flow as the fluid pathway transitions from proximal segment 202 to intermediate segment 214. Additionally, the larger ID of intermediate segment 214 reduces resistance to fluid flow because it provides a larger diameter (which is inversely proportional to resistance) for a portion of the interior length of a compatible valved cannula (e.g., valved cannula 220 of FIG. 2C). A longer length of intermediate segment (e.g., second length 235) allows fluid to flow a longer length / distance before transitioning to distal segment 204, which has the smallest ID of the three segments, thereby reducing resistance to fluid flow. For example, in certain embodiments, flow rate is increased by about 5% to about 30% or more compared to certain existing cannula designs. In some instances, flow rate can be increased by more than 30%, e.g., 30% to 35%, compared to certain existing cannula designs. In certain embodiments, the pressure drop is reduced proportionately, for example, by about 20% to about 35% or more. As previously mentioned, flow rate and pressure drop are affected by the segment passage ID and length, as well as the source pressure and fluid viscosity.

[0043] In certain embodiments, the third length 236 of the distal segment 204 is between about 0.0425 inches (about 1.0795 mm) and about 0.0575 inches (about 1.4605 mm), e.g., between about 0.045 inches (about 1.143 mm) and about 0.055 inches (about 1.397 mm), e.g., about 0.05 inches (about 1.27 mm). In certain embodiments, the third length 236 of the distal segment 204 is greater than 0.05 inches (1.27 mm), for example, if the outside of the distal segment 204 fits inside a valved cannula hub (e.g., shaft 228 in FIG. 2D ) and / or a cannula transition (e.g., cannula transition 230 in FIG. 2D ) or if the distal segment 204 has a recess. In certain embodiments, the third length 236 of the distal segment 204 is shorter than the second length 235 of the intermediate segment 214. In other embodiments, the third length 236 of the distal segment 204 may be less than 0.05 inches (1.27 mm).

[0044] Additionally, in certain embodiments, the distal segment 204 is shorter than some existing fluid cannula designs because the longer distal segments of such perfusion cannulas are a limiting factor for fluid flow. Flow rate is generally affected by the input pressure and viscosity of the fluid flowing through the perfusion cannula 200. Flow rate is also affected by the segment ID, because narrower cross-sections increase pressure loss and lead to reduced flow. Shortening the distal segment 204 reduces the distance the fluid must flow through the smallest ID (e.g., third ID 242), providing a longer, wider cross-section of the shaft 228 for the fluid to flow through, thereby preventing excessive pressure loss. In certain embodiments, shortening the length of the distal segment 204 minimizes the length of the path the fluid must travel through the segment of the perfusion cannula 200 with the smallest ID (e.g., distal segment 204), thereby reducing resistance to that fluid flow. For example, a shorter distal segment 204 may increase flow rate by approximately 5-30% or more compared to certain existing fluid cannula designs. In some instances, flow rate may increase by more than 30%, such as 30%-35% or more.

[0045] In certain embodiments, the relatively larger ID (e.g., second ID 248) and longer length (e.g., second length 235) of the intermediate segment 214, combined with the shortened length (e.g., third length 236) of the distal segment 204, results in the perfusion cannula 200 disclosed herein requiring a lower overall source pressure to maintain a given flow rate. In certain embodiments, the source pressure is reduced in proportion to the reduced flow resistance. In certain embodiments, the perfusion cannula embodiments disclosed herein provide an increased flow rate at a given source pressure. In certain embodiments, the increase in flow rate is generally about 5-30% or more. In certain embodiments, at a source pressure of, for example, 80 pounds per square inch (psi), the increase in flow rate is about 15-30% or more compared to certain existing 25-gauge perfusion cannula designs. In certain embodiments, at a source pressure of, for example, 30 psi, the increase in flow rate is about 5-20% or more compared to certain existing 25-gauge perfusion cannula designs.

[0046] In certain embodiments, the inner shaft length 244 of the perfusion cannula 200 (e.g., distal segment 204, transition section 207, intermediate segment 214, and second fillet 206B) is between about 0.1003 inches (about 2.5476 mm) and about 0.1357 inches (about 3.4468 mm), such as between about 0.1062 inches (about 2.6975 mm) and about 0.1298 inches (about 3.2969 mm), such as about 0.118 inches (about 2.9972 mm). In other embodiments, the inner shaft length 244 of the perfusion cannula 200 can be greater or less than 0.118 inches (2.9972 mm).

[0047] In certain embodiments, the overall length 246 of the perfusion cannula 200 is between about 0.2831 inches (about 7.1895 mm) and about 0.3830 inches (about 9.7269 mm), such as between about 0.2997 inches (about 7.6124 mm) and about 0.3663 inches (about 9.3040 mm), such as about 0.333 inches (about 8.4582 mm). In other embodiments, the overall length 246 of the perfusion cannula 200 may be greater or less than 0.333 inches (8.4582 mm).

[0048] It should be noted that although certain features are described herein in terms of specific dimensions or ranges of dimensions, other dimensions and / or IDs are also contemplated.

[0049] In certain embodiments, first transition portion 206 includes first fillet 206A and second fillet 206B, and second transition portion 207 includes third fillet 207A and fourth fillet 207B. In certain embodiments, first fillet 206A is concave and second fillet 206B is convex. In certain embodiments, third fillet 207A is concave and fourth fillet 207B is convex.

[0050] Proximal segment 202 and intermediate segment 214 are connected by a transition having fillets 206A and 206B, which causes the ID of the flow path to gradually decrease when transitioning between the cylindrical shape of proximal segment 202 and the cylindrical shape of intermediate segment 214. The gradual decrease in ID reduces flow resistance therethrough compared to an abrupt decrease in ID in a configuration where a proximal segment with a relatively wide ID transitions to an intermediate segment with a relatively narrow ID.

[0051] In certain embodiments, first transition portion 206 of perfusion cannula 200 may include a first chamfer or bevel positioned between fillets 206A and 206B. In certain embodiments, a transition angle θ (e.g., a transition angle) is formed between the first chamfer and an axis of one of segments 202 and 214, which may not be collinear with central axis 212. In certain embodiments, transition angle θ is formed between the first chamfer and central axis 212. In certain embodiments, transition angle θ is approximately 60 degrees, but in further embodiments, transition angle θ may be approximately 15 degrees, up to and including approximately 90 degrees. In further embodiments, transition angle θ is greater than 90 degrees.

[0052] The configuration of first transition portion 206 may improve fluid flow through perfusion cannula 200. For example, first transition portion 206 may include a first chamfer, which creates a funnel-shaped feature within perfusion cannula 200 with a gradually decreasing ID between proximal segment 202 and intermediate segment 214. The first chamfer may help prevent excessive pressure loss compared to some existing perfusion cannula transitions by reducing the cross section for fluid in a linearly decreasing manner. In certain embodiments, first transition portion 206 may include a first chamfer or bevel rather than a fillet (e.g., fillets 206A and 206B).

[0053] The middle segment 214 and the distal segment 204 are connected by a transition having fillets 207A and 207B, which results in a gradual decrease in the ID of the flow path when transitioning between the cylindrical shape of the middle segment 214 and the cylindrical shape of the distal segment 204. The gradual decrease in ID reduces the flow resistance therethrough compared to the abrupt decrease in ID in a configuration where a middle segment with a wide ID transitions to a distal segment with a narrow ID.

[0054] In certain embodiments, the third distal end 205B of the distal segment 204 may include a sixth fillet and / or a second chamfer or bevel, which may be convex. The sixth fillet and / or second chamfer may advantageously facilitate insertion of the perfusion cannula 200 into the valved cannula 220 (e.g., in FIG. 2C ) by gradually increasing the outer diameter of the third distal end 205B.

[0055] 2B , fillets 206A, 206B, 207A, and 207B are formed on the inner walls of transition sections 206, 207, and 208, respectively. In certain embodiments, these fillets are formed on the inner and / or outer walls of transition sections 206, 207, and 208, respectively. In certain embodiments, the inner and / or outer walls of segments 202, 204, and 214 are parallel or tapered with respect to central axis 212. In some embodiments, the wall thickness of segments 202, 204, and 214 and transition sections 206, 207, and 208 is constant. In certain embodiments, the wall thickness may be variable or vary by feature (e.g., first transition section 206, distal segment 204).

[0056] Fillets described herein, including fillets 206A and 206B, can have one or more position angles (e.g., position angle 253) referenced to the position of the fillet's midpoint relative to central axis 212. The position angle can be formed between central axis 212 and a line tangent to the fillet's midpoint. In certain embodiments, the position angle can be between 1 and 85 degrees. In certain embodiments, the position angle can be between 10 and 60 degrees. In certain embodiments, the position angle can be between 20 and 40 degrees. For example, position angle 253 can be approximately 75 degrees. In certain embodiments, the fillet can be on an inner surface of a transition portion (e.g., first transition portion 206). In further embodiments, the fillet can be on an outer surface of the transition portion.

[0057] In certain embodiments, a continuous flow path is formed between first proximal end 203A and third distal end 205B of perfusion cannula 200. Accordingly, the curvature of transitions 206, 207, and 208 may allow fluid to flow smoothly through perfusion cannula 200 by reducing fluid friction losses, thereby advantageously improving fluid performance. In certain embodiments, the interior walls of segments 202, 214, and 204 and transitions 206, 207, and 208 are seamlessly connected to form a smooth interior surface such that there are no disjointed transitions, interruptions, or inconsistencies between segments 202, 214, and 204 and transitions 206, 207, and 208.

[0058] 2A, perfusion cannula 200 has a unitary body formed from three cylindrical sections of substantially uniform diameter: a wide proximal cylindrical section (e.g., proximal segment 202), a medium intermediate cylindrical section (e.g., intermediate segment 214), and a narrow distal cylindrical section (e.g., distal segment 204). The medium intermediate cylindrical section and the wide proximal cylindrical section are connected by a transition section consisting of two fillets, which gradually reduces the ID of the flow path when transitioning from the wide proximal cylindrical section to the medium intermediate cylindrical section, avoiding the increase in flow resistance that would otherwise result from a sudden decrease in ID between any two segments.

[0059] FIG. 2C illustrates a perspective view of the irrigation cannula 200 of FIG. 2A coupled to a valved cannula 220, in accordance with certain embodiments of the present disclosure. In particular, FIG. 2C illustrates the outer contours and certain exterior features of the irrigation cannula 200 and the valved cannula 220. FIG. 2D illustrates a side cross-sectional view of the irrigation cannula 200 coupled to the valved cannula 220 of FIG. 2C, in accordance with certain embodiments of the present disclosure. In particular, FIG. 2D illustrates the inner contours and certain interior features of the irrigation cannula 200 coupled to the valved cannula 220. In certain embodiments, the irrigation cannula 200 is configured to be inserted into the valved cannula 220 and to irrigate fluid through the valved cannula 220 and into the ocular space of a patient's eye. In certain embodiments, the valved cannula 220 is a valved trocar cannula.

[0060] Valved cannula 220 generally includes an overcap 222, a hub 226, and a hollow tube or shaft 228. Hub 226 and shaft 228 are connected by a cannula transition 230. The inner diameter (ID) of hub 226 (e.g., ID 227 in FIG. 2D ) is larger than the ID of shaft 228 (e.g., ID 229 in FIG. 2D ). Valved cannula 220 further includes a recess 232, which may be part of hub 226 and / or cannula transition 230.

[0061] In certain embodiments, at least a portion of the perfusion cannula 200 frictionally engages with internal features of the valved cannula 220 when the perfusion cannula 200 is inserted therein. For example, at least a portion of the intermediate segment 214 frictionally engages with internal features of the valved cannula 220 and / or at least a portion of the distal segment 204 frictionally engages with the interior of the shaft 228, resulting in a "tube-in-tube" configuration between the distal segment 204 and the shaft 228. The tube-in-tube configuration provides consistent fluid flow and operating pressure during use of the perfusion cannula 200. In certain embodiments, the distal segment 204 of the perfusion cannula 200 is sized to closely fit within a particular gauge size of the valved cannula 220. For example, the distal segment 204 has an outer diameter configured to closely fit within the shaft 228 of a 23-gauge valved cannula, a 25-gauge valved cannula, a 27-gauge valved cannula, or the like.

[0062] The different segments (e.g., 214 and 204) may pass through different portions (e.g., hub 226 or shaft 228) of perfusion cannula 200 when it is coupled to valved cannula 220. For example, when perfusion cannula 200 and valved cannula 220 are connected, middle segment 214 of perfusion cannula 200 may be disposed within hub 226 of valved cannula 220, while distal segment 204 is disposed within shaft 228.

[0063] 2D , the hub 226 of the valved cannula 220 radially surrounds and is coupled to the intermediate segment 214 of the perfusion cannula 200 when the perfusion cannula 200 is inserted into the valved cannula 220. In certain embodiments, when inserted into the valved cannula 220, the intermediate segment 214 is disposed solely within (i.e., radially inward of) the hub 226, or solely within the hub 226 and the cannula transition section 230, and the intermediate segment 214 does not extend into the shaft 228. Because the intermediate segment 214 does not extend into the shaft 228, the dimensions of the intermediate segment 214 are not limited by the dimensions of the shaft 228, and in certain embodiments, the smallest ID of the distal segment 204 (e.g., third ID 242 in FIG. 2D ) is greater than the ID 229 of the shaft 228 of the valved cannula 220. As previously mentioned, valved cannula 220 can be a 23 gauge valved cannula, a 25 gauge valved cannula, a 27 gauge valved cannula, etc. The relatively large ID of intermediate segment 214 (e.g., second ID 248 in FIG. 2B ) compared to ID 229 of shaft 228 is configured to reduce the overall flow resistance and pressure drop through perfusion cannula 200, as valved cannula 220 restricts fluid flow to a level lower than that which perfusion cannula 200 can practically accommodate.

[0064] Intermediate segment 214 further allows irrigation cannula 200 to universally fit with different gauge valved cannulas because intermediate segment 214 does not need to accommodate different IDs (e.g., ID 229) on its shaft (e.g., shaft 228). For example, irrigation cannula 200 may be universally coupled to a 23 gauge valved cannula, a 25 gauge valved cannula, a 27 gauge valved cannula, etc. Thus, the versatility of irrigation cannula 200 advantageously reduces the number of different parts required for a surgical procedure.

[0065] In certain embodiments, proximal segment 202 is coupled to intermediate segment 214 through fillets 206A and 206B such that when irrigation cannula 200 is fully inserted into valved cannula 220, the surface between fillets 206A and 206B is substantially flush with the top surface of overcap 222. Compared to irrigation cannulas that have tamper-evident transitions between the proximal and intermediate or distal segments, fillets 206A and 206B may provide a visual cue for the operator to confirm that irrigation cannula 200 is fully inserted into valved cannula 220.

[0066] In certain embodiments, the perfusion cannula 200 may also include retention features for frictionally engaging with internal features of certain embodiments of the valved cannula 220. For example, the intermediate segment 214 or the distal segment 204 may have a recess configured to mate with, closely fit, and / or conform to the recess 232.

[0067] In certain embodiments, recess 232 is sized to provide sufficient resistance between irrigation cannula 200 and valved cannula 220 to keep irrigation cannula 200 in place during a procedure. In certain embodiments, the resistance between recess 232 and irrigation cannula 200 is less than that required to withdraw valved cannula 220 from the eye when irrigation cannula 200 is being removed from valved cannula 220. For example, when irrigation cannula 200 is withdrawn from valved cannula 220 while the valved cannula 220 is within the eye, the valved cannula 220 does not withdraw from the eye. In certain embodiments, the resistance between irrigation cannula 200 and valved cannula 220 is such that irrigation cannula 200 cannot be removed from valved cannula 220 without first removing valved cannula 220 from the eye. In certain embodiments, resistance is created between other regions or sections of the perfusion cannula 200 and the valved cannula 220. For example, in some embodiments, the exterior of the distal segment 204 frictionally engages the interior surface of the hub 226 and / or the cannula transition 230.

[0068] In summary, embodiments of the present disclosure include fluid cannulas for improving fluid administration and fluid flow during ophthalmic surgical procedures. For example, the embodiments described herein provide efficient administration of ocular irrigation fluids and tamponade, thereby facilitating improved intraocular pressure maintenance. Thus, such cannulas are particularly beneficial during irrigation of the eye by reducing fluid resistance and therefore allowing for lower operating pressures to achieve a given flow rate.

[0069] Illustrative Embodiments Embodiment 1: A surgical cannula device comprising: a proximal segment having a first length and a first inner diameter (ID); an intermediate segment connected to the proximal segment having a second length and a second ID smaller than the first ID; and a distal segment connected to the intermediate segment having a third length shorter than the second length and a third ID smaller than the second ID.

[0070] Embodiment 2: The cannula device of embodiment 1 above, wherein the second ID of the intermediate segment is greater than half of the first ID of the proximal segment.

[0071] Embodiment 3: The cannula device of embodiment 1 above, wherein at least a portion of the distal segment is configured to be disposed within the shaft of a valved cannula including a hub, a shaft, and a cannula transition between the hub and the shaft.

[0072] Embodiment 4: The cannula device of embodiment 3 above, wherein at least a portion of the distal segment is configured to frictionally engage an inner surface of the shaft of the valved cannula.

[0073] Embodiment 5: The cannula device of embodiment 1 described above, wherein at least a portion of the intermediate segment is configured to be positioned within a hub or cannula transition of a valved cannula including a hub, a shaft, and a cannula transition between the hub and the shaft.

[0074] Embodiment 6: The cannula device of embodiment 5 above, wherein at least a portion of the intermediate segment is configured to frictionally engage an inner surface of the hub or cannula transition of the valved cannula.

[0075] Embodiment 7: The cannula device of embodiment 1 described above, further comprising a first transition portion connecting the distal end of the proximal segment and the proximal end of the intermediate segment, the first transition portion comprising a first fillet and a second fillet.

[0076] Embodiment 8: The cannula device of the above-mentioned embodiment 7, further comprising a second transition portion connecting the distal end of the intermediate segment and the proximal end of the distal segment, the second transition portion comprising a third fillet and a fourth fillet.

[0077] Embodiment 9: A surgical cannula device comprising: a proximal segment having a first inner diameter (ID), a first length, a first proximal end, and a first distal end; an intermediate segment having a second ID smaller than the first ID, a second length, a second proximal end, and a second distal end; a first transition section connecting the proximal segment and the intermediate segment via the first distal end and the second proximal end, the first transition section comprising a first fillet and a second fillet; a distal segment connected to the intermediate segment, the distal segment having a third ID smaller than the second ID, a third length longer than the second length, a third proximal end, and a third distal end; and a second transition section connecting the intermediate segment and the distal segment via the second distal end and the third proximal end, the second transition section comprising a third fillet and a fourth fillet.

[0078] Embodiment 10: The cannula device of embodiment 9 above, wherein the second ID of the intermediate segment is greater than half of the first ID of the proximal segment.

[0079] Embodiment 11: The cannula device of embodiment 9 described above, wherein at least a portion of the distal segment is configured to be positioned within the shaft of a valved cannula including a hub, a shaft, and a cannula transition between the hub and the shaft, and at least a portion of the intermediate segment is configured to be positioned within the hub or cannula transition of the valved cannula.

[0080] The previous description is provided to enable any person skilled in the art to practice the various embodiments described herein. The examples described herein are not intended to limit the scope, applicability, or embodiments set forth in the claims. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments. For example, changes may be made to the function and arrangement of elements discussed without departing from the scope of the disclosure. In various examples, various procedures or components may be omitted, substituted, or added as appropriate. For example, described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of aspects described herein. Additionally, the scope of the disclosure is intended to encompass similar apparatuses or methods practiced using structure, functionality, or structure and functionality in addition to or other than various aspects of the disclosure described herein. It should be understood that any aspect of the disclosure disclosed herein may be realized by one or more elements recited in a claim.

[0081] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects.

[0082] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including a single element. As an example, "at least one of a, b, or c" is intended to encompass not only a, b, c, ab, ac, bc, and abc, but also any combination of multiples of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other permutation of a, b, and c).

[0083] The following claims are not intended to be limited to the embodiments set forth herein but are to be accorded the full scope consistent with the claim language. In the claims, when an element is referred to in the singular, it means "one or more," not "only one," unless specifically stated otherwise. The term "some" refers to one or more unless specifically stated otherwise. No element of a claim is to be construed under the provisions of 35 U.S.C. § 112(f) unless the element is expressly recited using the phrase "means for," or, in the case of a method claim, unless the element is recited using the phrase "step for." All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known, or later become known, to those skilled in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be made available to the public, regardless of whether such disclosure is expressly recited in the claims.

Claims

1. a proximal segment comprising a first length and a first inner diameter (ID); an intermediate segment coupled to the proximal segment, the intermediate segment including a second length and a second ID less than the first ID; a distal segment coupled to the intermediate segment, the distal segment including a third length greater than the second length and a third ID less than the second ID; A cannula device for surgical procedures, comprising:

2. The cannula apparatus of claim 1 , wherein the second ID of the intermediate segment is greater than half the first ID of the proximal segment.

3. The cannula apparatus of claim 1 , wherein at least a portion of the distal segment is configured to be disposed within the shaft of a valved cannula including a hub, a shaft, and a cannula transition between the hub and the shaft.

4. The cannula apparatus of claim 3 , wherein the at least a portion of the distal segment is configured to frictionally engage an inner surface of the shaft of the valved cannula.

5. 2. The cannula device of claim 1, wherein at least a portion of the intermediate segment is configured to be disposed within a hub or a cannula transition of a valved cannula including a hub, a shaft, and a cannula transition between the hub and the shaft.

6. The cannula apparatus of claim 5 , wherein the at least a portion of the intermediate segment is configured to frictionally engage an inner surface of the hub or cannula transition portion of the valved cannula.

7. The cannula apparatus of claim 1 , further comprising a first transition portion connecting a distal end of the proximal segment and a proximal end of the intermediate segment, the first transition portion comprising a first fillet and a second fillet.

8. The cannula apparatus of claim 7 , further comprising a second transition portion connecting the distal end of the intermediate segment and the proximal end of the distal segment, the second transition portion including a third fillet and a fourth fillet.

9. The cannula apparatus of claim 8 , wherein the third length of the distal segment is less than the combined length of the intermediate segment and the second transition section.

10. a proximal segment including a first inner diameter (ID), a first length, a first proximal end, and a first distal end; an intermediate segment coupled to the proximal segment, the intermediate segment including a second ID smaller than the first ID, a second length, a second proximal end, and a second distal end; a first transition portion connecting the proximal segment and the intermediate segment via the first distal end and the second proximal end, the first transition portion including a first fillet and a second fillet; a distal segment coupled to the intermediate segment, the distal segment including a third ID less than the second ID, a third length greater than the second length, a third proximal end, and a third distal end; a second transition portion connecting the intermediate segment and the distal segment via the second distal end and the third proximal end, the second transition portion including a third fillet and a fourth fillet; A cannula device for surgical procedures, comprising:

11. The cannula apparatus of claim 10, wherein the second ID of the intermediate segment is greater than half the first ID of the proximal segment.

12. The cannula apparatus of claim 10 , wherein the third length of the distal segment is less than the combined length of the intermediate segment and the second transition section.

13. The cannula apparatus of claim 10 , wherein at least a portion of the distal segment is configured to be disposed within the shaft of a valved cannula including a hub, a shaft, and a cannula transition between the hub and the shaft.

14. The cannula apparatus of claim 13, wherein the at least a portion of the distal segment is configured to frictionally engage an inner surface of the shaft of the valved cannula.

15. 11. The cannula device of claim 10, wherein at least a portion of the intermediate segment is configured to be disposed within a hub or cannula transition of a valved cannula including a hub, a shaft, and a cannula transition between the hub and the shaft, and wherein the at least a portion of the intermediate segment is configured to frictionally engage an inner surface of the hub or cannula transition of the valved cannula.

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