Microsurgical procedures frequently require precision cutting and/or removing of various body tissues. For example, certain ophthalmic surgical procedures require cutting and removing portions of the vitreous humor, a transparent jelly-like material that fills the posterior segment of the eye. The vitreous humor, or vitreous, is composed of numerous microscopic fibrils that are often attached to the retina. Therefore, cutting and removing the vitreous must be done with great care to avoid traction on the retina, the separation of the retina from the choroid, a retinal tear, or, in the worst case, cutting and removal of the retina itself. In particular, delicate operations such as mobile tissue management (e.g. cutting and removal of vitreous near a detached portion of the retina or a retinal tear), vitreous base dissection, and cutting and removal of membranes are particularly difficult.
Microsurgical cutting probes used in posterior segment ophthalmic surgery may include a straight hollow outer cutting member, a straight (or slightly bent for shearing) hollow inner cutting member arranged coaxially with and movably disposed within the hollow outer cutting member, a port extending radially through the outer cutting member near the distal end of the outer cutting member, and a port extending radially through the inner cutting member near the distal end of the inner cutting member (and/or the cutting member may be open at the distal end). Vitreous humor and/or membranes are aspirated into the open port of the outer cutting member and the inner member is actuated to distally extend the inner cutting member. As the inner cutting member extends distally, cutting surfaces on both the inner and outer cutting members cooperate to cut the vitreous and/or membranes, and the cut tissue is then aspirated away through the inner cutting member. Vitreous and/or membranes are then aspirated into the open ports of both the outer and inner cutting members and the inner member is actuated to proximally retract the inner cutting member. The inner and outer cutting members cooperate to again cut vitreous and/or membranes and aspirate the cut tissue away. The actuated extension and retraction of the inner cutting member is repeated at dynamic cycle rates between several tens to several hundred times per second.
A vitrectomy probe includes a hand-graspable body and an outer tube extending from the hand-graspable body. The outer tube includes a closed distal end and a first port sized to receive tissue. The vitrectomy probe also includes an inner tube within the outer tube. In various embodiments, the outer tube and/or the inner tube are curved. In some embodiments, the curvature of the outer tube/inner tube is adjustable.
For a more complete understanding of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings in which:
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide a further explanation of the present invention as claimed.
For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is intended. Any alterations and further modifications to the described systems, devices, and methods, and any further application of the principles of the present disclosure are fully contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the systems, devices, and/or methods described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. For the sake of brevity, however, the numerous iterations of these combinations will not be described separately. For simplicity, in some instances the same reference numbers are used throughout the drawings to refer to the same or like parts.
The present disclosure is directed to surgical devices, systems, and methods for performing ophthalmic surgeries. The devices, systems, and methods are arranged and configured to provide a curved vitrectomy probe for a vitrectomy procedure. A curved vitrectomy probe may provide access for greater peripheral vitreous removal and potentially facilitate reduced reoperation rates. Potentially, the result may be better patient visual acuity outcomes. Various aspects of these features will be discussed further below.
In an embodiment, the vitrectomy probe system's pneumatic driver 122 (
In operation, pneumatic pressure is directed alternately from the source 120 to the first and second ports 140, 142 to operate the vitrectomy probe 112. The on-off pneumatic driver 122 alternates between its two positions very rapidly to alternatingly provide pneumatic pressure to the first and second ports 140, 142. Although shown with a single pneumatic driver 122, other embodiments include two pneumatic drivers, one associated with each of the two ports 140, 142. These embodiments operate similar to the manner described, with the drivers being configured to independently receive operating signals from the controller 126 (
Generally, the inner cutting tube 154 oscillates within the outer cutting tube 152 in response to the probe actuator. In an embodiment, the inner cutting tube 154 is driven by air pressure directed on opposing sides of the diaphragm 156. In one example of operation, if air pressure is increased at the first port 140, the diaphragm 156 will move distally, displacing the inner cutting tube 154 relative to the outer cutting tube 152, thereby moving a first cutting edge on a distal end of the inner cutting tube 154 in the distal direction and cutting tissue. This cuts any vitreous material which may have been aspirated into a tissue-receiving outer port of the outer cutting tube 152. The vitreous may be aspirated away at a distal end of the inner cutting tube 154. Venting the pressure at the first port 140 and increasing the pressure at the second port 142 moves the diaphragm 156 proximally which results in moving the inner cutting tube 154 in the proximal direction. In some embodiments, the inner cutting tube 154 may also include a side port for cutting. In this embodiment, as the diaphragm 156 moves proximally, a second cutting edge facing a proximal direction near the distal end of the inner cutting tube 154 may also move in the proximal direction, cutting any vitreous material which may have entered the ports of the inner cutting tube 154 and outer cutting tube 152 while at least partially aligned.
In alternative embodiments, the probe actuator may include a piston motor in place of a diaphragm. In this type of embodiment, the cutter 150 is arranged so that movement of the piston also moves the inner cutting tube 154 of the cutter 150. Yet other embodiments include other types of pneumatic or electric motors that drive the inner cutting tube 154, as will be recognized by those skilled in the relevant art(s).
The outer cutting tube 152 has a closed end at the distal end 166 and an outer port 408 that may receive various material, such as tissue. In an embodiment, the tissue may be ophthalmic tissue such as vitreous and/or membrane. The outer port 408 has a distal portion, nearest the distal end 166, and a proximate portion. Each of the distal and proximate portions of the outer port 408 may include a cutting edge.
In some embodiments, the inner tip 406 may be curved slightly more than the outer tube to provide bias toward the outer port 408. This different cross section at the tip 406 may provide shearing edges between the inner cutting tube 154 and the outer cutting tube 152. This may facilitate smooth, progressive shearing of vitreous/membranes and may reduce wear to the vitrectomy probe 112 over time. In some embodiments, both the inner and outer tubes may have round cross sections. In alternate embodiments, the slightly increased curve in the tip 406 may impart a unique tubular cross section to the inner cutting tube 154, such as a substantially oval cross section, in contrast to the rest of the inner cutting tube 154 that is approximately round. This may allow an oval cross section at the tip 406 to distribute the sliding wear at the tip 406 over a greater surface area that comes in contact with the inner surface of the distal end of the outer cutting tube 152. The oval cross section of the tip 406 may also decrease the size of the annular space between the tip 406 and the inner surface of the distal end of the outer cutting tube 152, which may decrease the potential for vitreous incarceration and vitreoretinal traction.
Returning to
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As seen in
In another embodiment, the device could be composed of a curved and elastic inner cannula and a similarly curved and elastic outer tubular cannula. In these embodiments, both the inner and outer cannula may be constructed from a superelastic material such as Nitinol (or different flexible/elastic materials).
In various embodiments, a mechanism and actuator could be utilized to make an articulating device vitrectomy probe. For example, a user actuated slider, lever, or wheel (e.g., actuated through movement by the user's fingers) could be used to straighten or curve the distal shaft on demand. As seen in
As another example, a slider 603 may be used to slide an internal shaft 601 up and down (as seen in
The curvature of the outer tube 152 may be adjustable during surgery or may be adjusted prior to surgery and hold the constant set curvature during surgery. In some embodiments, the curved probe may provide better access to the far peripheral vitreous, while simultaneously providing clearance around the human crystalline lens, which, if touched, may precipitate cataract formation.
At 800, the curvature of the outer tube 152 of the vitrectomy probe may be adjusted (e.g., as discussed above with respect to
At 802, the vitrectomy probe 112 causes the inner cutting tube 154 to slide in a distal direction. As the cutting edge at the tip of the inner cutting tube 154 moves distally, the cutting edge cuts tissue that has entered the outer port of the outer cutting tube 152. The inner cutting tube 154 may be curved/bent slightly more than the outer tube near its distal end to provide a flexural side load, causing the guiding surface to be engaged with an inner surface of the outer cutting tube 152. In this angled position, the tip is disposed in a position that is a suitable distance removed from, or is disposed to also engage with, the inner surface of the outer cutting tube 152 in order to cut fibrils or tissue without creating damaging traction on the retina.
At 804, a guiding surface of the inner cutting tube may guide the distal sliding motion of the inner cutting tube 154 as the tip of the inner cutting tube 154 traverses the gap of the outer port in the distal direction. The guiding surface guides the sliding motion, for example, by slidably bearing on an inner surface of the outer cutting tube 152 at a proximal side of the outer port. The guiding motion assists in preventing the tip from protruding too far beyond a diameter of the outer cutting tube 152 as a result of the bend in the inner cutting tube 154.
At 806, the vitrectomy probe 112 aspirates any cut tissue from the distal end of the inner cutting tube 154, for example via the distal port. The aspiration may be via the suction port 162 that connects the vitrectomy probe 112 to an aspiration system on the base housing 102. This may occur, for example, when the inner cutting tube 154 has been fully extended in the distal direction, in the “closed” position such that the inner port 404 and the outer port 408 are at least partially aligned.
At 808, the vitrectomy probe 112 causes the inner cutting tube 154 to slide in the proximal direction. As the cutting edge at the proximal side of the tip moves proximally, the cutting edge cuts tissue that has entered the inner port and the outer port while they are aligned, either substantially or partially.
At 810, the guiding surface guides the proximal sliding motion of the inner cutting tube 154 as the tip 406 traverses the gap of the outer port in the proximal direction. The guiding surface guides the sliding motion, for example, by slidably bearing on an inner surface of the outer cutting tube 152 at a proximal side of the outer port.
At 812, the vitrectomy probe 112 aspirates any cut tissue and/or fluids from the area of the inner port. The aspiration may again be via the suction port 162. In some embodiments, the inner cutter may have a simple inner port 404 without side lobes. In some embodiments, the inner cutter may not have an inner port at all (e.g., tissue may be cut primarily by edge 504 traversing outer port 408). In embodiments with side lobes, at least some of the cut tissue and/or fluids may be aspirated at 812 via one or both of the side lobes. This may facilitate the more efficient removal of vitreous/membranes without excessive flow of balanced saline solution. In some embodiments, the aspiration system may draw a constant or continuous vacuum pressure at the suction port 162 and the bore (lumen) of the inner cutting tube 154.
In embodiments with side lobes 410, the side lobes 410, together, may serve to define the guiding surface 402 as a protrusion in the distal direction from the otherwise generally uniform shape of the inner port 404 into the space of the inner port 404. The guiding surface 402 provides an additional surface which may slidably bear on an inner surface of the outer cutting tube 152 as the inner cutting tube 154 axially moves in the distal and proximal directions during operation.
As a result, in embodiments where the inner cutting tube 154 has been curved more than the outer tube to provide a flexural side load, the guiding surface 402 may remain in contact with the inner surface of the outer cutting tube 152 while the inner cutting tube 154 axially moves in the distal direction. This contact between the guiding surface 402 and the inner surface of the outer cutting tube 152 may prevent the inner cutting tube 154 from protruding too far out of the outer port 408, thereby decreasing the chance of tortuous or impeded cutter motion and reducing wear on the vitrectomy probe 112. The guiding surface 402 may be formed from the rest of the inner cutting tube 154. Alternatively, the guiding surface may be separately formed and secured in place at a proximal side of the inner port 404 using welding, brazing, cements, adhesives, friction fits, or other methods.
In embodiments with side lobes, the side lobes 410 may extend the surface area of the inner port 404, thereby allowing more fluid flow via the inner port 404 than would be available to a port with a conventional contour (e.g., without side lobes) in the inner cutting tube 154. In an embodiment, addition of the side lobes 410 to the vitrectomy probe 112 in embodiments of the present disclosure enables operation of the vitrectomy probe 112 at reduced vacuum settings while still providing equivalent vitreous flow and reduced traction transmitted to the retina relative to conventional vitrectomy probes. In an embodiment, the length of each side lobe 410 along the longitudinal axis of the inner cutting tube 154 is less than a width of the inner port 404 between the tip 406 and the proximal portion where the guiding surface 402 is located. In an alternative embodiment, the length of each side lobe 410 along the longitudinal axis of the inner cutting tube 154 is greater than a width of the inner port 404 between the tip 406 and the proximal portion where the guiding surface 402 is located.
The size of the side lobes 410 may impact how much additional fluid flow is possible above and beyond what is already available were the inner port 404 shaped in a conventional configuration, e.g. in a round or oval shape. This is because the vitreous humor, as well as tractional and vascular membranes that are commonly removed by surgical use of vitrectomy probes, are non-homogenous, non-Newtonian substances that tend to resist flow through small orifices and lumens such as those in conventional vitrectomy probes. Further, balanced saline solution—which is commonly used as an adjunct during vitreoretinal surgery—is a low viscosity Newtonian fluid that is much more able to flow through smaller passages. As a result, aspiration flow in cutter ports of conventional vitrectomy probes may result in a disproportionately high amount of balanced saline solution instead of vitreous/membranes. The larger inner port size afforded by the side lobes 410 in embodiments of the present disclosure may facilitate the more efficient removal of vitreous/membranes without excessive flow of balanced saline solution.
800 through 812 may continue throughout the duration of operation of the vitrectomy probe 112, resulting in cutting cycle of the vitrectomy probe 112 with improved fluid flow and reduced sliding wear on the vitrectomy probe 112 over time. This may result in a longer lasting vitrectomy probe, a smoother cutting cycle, and greater cut rates while decreasing risks of traction on the retina.
Persons of ordinary skill in the art will appreciate that the embodiments encompassed by the present disclosure are not limited to the particular exemplary embodiments described above. In that regard, although illustrative embodiments have been shown and described, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure. It is understood that such variations may be made to the foregoing without departing from the scope of the present disclosure.
Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the present disclosure.
Number | Date | Country | |
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62218900 | Sep 2015 | US |