Adjustable stiffener for surgical instruments

Abstract

To provide an adjustable stiffener for surgical instruments.SOLUTION: The present disclosure generally relates to microsurgical instruments having variable stiffness such as microsurgical instruments having variable stiffness, e.g., for ophthalmic surgical procedures. In one embodiment, a surgical instrument includes a probe and a stiffener assembly. The stiffener assembly further includes a stiffener formed of a hollow tubular member substantially surrounding at least a portion of a length of the probe. Actuation of the stiffener along the length of the probe adjusts the stiffness of the probe, thus allowing a user to better control the surgical instrument.SELECTED DRAWING: Figure 8A

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority of U.S. Provisional Patent Application No. 62 / 946,598, filed on December 11, 2019, with the title "ADJUSTABLE STIFFENER FOR SURGICAL INSTRUMENTS", inventors Bill Chen, James Y. Chon, and John R. Underwood, and incorporates by reference the entire content thereof into this specification as if fully and completely set forth herein.

Background Art

[0002] Ongoing efforts to minimize the invasiveness of surgical procedures, such as ophthalmic surgery, have led to the development of small surgical instruments for micro - incision techniques. Small vitrectomy, also known as minimally invasive vitreous surgery (MIVS), is a typical example of one such type of surgical procedure using small instruments. Examples of common eye conditions that can be treated by MIVS include retinal detachment, macular hole, epiretinal membrane, and vitreous hemorrhage. Compared to more invasive vitrectomy, the benefits associated with modern MIVS include, in particular, access to larger lesions, higher fluid stability, improved patient comfort, reduced conjunctival scarring, reduced postoperative inflammation, and earlier visual recovery. Thus, the adoption of MIVS and other micro - incision techniques has been expanding in recent years.

[0003] Despite the aforementioned benefits of minimally invasive techniques and their widespread support, there remain numerous challenges in the use of small surgical instruments, particularly in the field of ophthalmology. One concern frequently mentioned among surgeons is the rigidity of the instruments. As the diameter of these minimally invasive instruments, such as vitreous resection probes, decreases, their stiffness is reduced, making it difficult for the surgeon to control the instrument during some eye surgical procedures. In small ophthalmic surgical instruments, for example, the tip of the instrument may move in an unintended direction at the margins of the eye, thus making extremely difficult delicate procedures such as the peeling of membranes from the retinal surface. Summary of the Invention Problems to be Solved by the Invention

[0004] Accordingly, there is a need in the art for improvements in methods and devices for minimally invasive ophthalmic surgery. Means for Solving the Problems

[0005] In one embodiment, the surgical instrument comprises a base unit, a probe, and a stiffening member assembly. The base unit is configured to be held by a user. The probe is disposed through a first opening provided at the distal end of the base unit and has a length parallel to its longitudinal axis. The stiffening member assembly includes a stiffening member extending through the first opening provided in the base unit and an actuating mechanism configured to actuate the stiffening member along the length of the probe. The stiffening member is formed of a hollow tubular member that surrounds at least a portion of the probe and is slidably coupled thereto.

[0006] To better understand the features of the present disclosure enumerated above, a more detailed description of the present disclosure, briefly summarized above, can be obtained by referring to the embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate exemplary embodiments and should not be considered as limiting the scope, as other equally effective embodiments may be recognized.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2A

Figure 2B

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Figure 8A

Figure 8B

Modes for Carrying Out the Invention

[0008] For ease of understanding, where possible, the same reference numerals are used to denote the same elements common to multiple drawings. It is contemplated that the elements and features of one embodiment may be beneficially incorporated into other embodiments without further description.

[0009] The present disclosure generally relates to a microsurgical instrument having variable stiffness, and more particularly to a microsurgical instrument having variable stiffness for ophthalmic surgery. In one embodiment, the surgical instrument includes a probe and a stiffening member assembly. The stiffening member assembly further includes a stiffening member formed of a hollow tubular member that substantially surrounds at least a portion of the length of the probe. Actuation of the stiffening member along the length of the probe adjusts the stiffness of the probe, thereby enabling the user to better control the surgical instrument.

[0010] FIG. 1 shows a perspective view of an exemplary instrument 100 according to one embodiment described herein. As shown in FIG. 1, the instrument 100 includes a probe or needle 110 (hereinafter referred to as "probe") and a base unit 120. The probe 110 includes a proximal portion 112 and a distal portion 114 that terminates at a distal end 116 on the distal side. In some embodiments, the proximal portion 112 extends through a substantial portion of an internal chamber (shown in FIGS. 2A and 2B) of the base unit 120.

[0011] In one example, the probe 110 is an elongated cutting member of a vitrectomy probe. For example, the probe 110 may be inserted into a cannula for performing vitreous surgery, either as a suction type or a non-suction type. The probe 110 may include a hollow tube having a diameter of less than about 20 gauge. For example, the diameter of the probe 110 is less than about 23 gauge, such as less than about 25 gauge. In one embodiment, the diameter of the probe 110 is approximately 27 gauge. In a further example, the probe 110 may include a lighting device, a laser guide, a suction device, forceps, scissors, a retractor, or other suitable device disposed within or coupled thereto.

[0012] Generally, the probe 110 is formed of a material suitable for minimally invasive surgical procedures, such as vitreoretinal surgery involving removal of the vitreous of the eye, or other surgical procedures. For example, the probe 110 is formed of surgical grade stainless steel, aluminum, or titanium.

[0013] The probe 110 is disposed partially and longitudinally through the distal end 121 of the base unit 120 adjacent to the proximal portion 112 and can be attached directly or indirectly therein within an internal chamber (internal chamber 124 as described below) of the base unit 120. In one embodiment, the base unit 120 is a handpiece having an outer surface 122 configured to be held by a user such as a surgeon. For example, the base unit 120 can be contoured to substantially fit in a user's hand. In some embodiments, the outer surface 122 may be textured or have one or more gripping features formed therein, such as one or more grooves and / or ridges.

[0014] The base unit 120 can house at least a portion of a drive mechanism operable to reciprocate the probe 110 relative thereto within the base unit 120. In one example, the drive mechanism can be a pneumatic drive mechanism including a diaphragm. The base unit 120 can further be provided with one or more ports 123 at its proximal end 125 for delivering one or more supply lines into the internal chamber 124. For example, the one or more ports 123 can provide a connection between the base unit 120 and a vacuum source for suction. In another example, the one or more ports 123 provide a connection to a pneumatic source, a fluid pressure source, or a power source to operate a drive mechanism, a lighting device, a laser, or other suitable device within or coupled to the base unit 120.

[0015] The instrument 100 further includes a stiffening member assembly 130 that includes a stiffening member 132 slidably coupled to the probe 110 and substantially surrounding at least a portion thereof. The stiffening member 132 is adjustable relative to the probe 110, allowing a user to position the stiffening member 132 (e.g., the distal end of the stiffening member 132) at different points along the length L of the probe 110 (shown in FIGS. 2A and 2B) outside of the base unit 120. Thus, the user can selectively adjust the level of stiffness of the probe 110 by repositioning the stiffening member 132 relative to the distal end 116, thereby manipulating the amount of support provided to the probe 110 and stabilizing the instrument 100 during use of the instrument.

[0016] FIGS. 2A and 2B show schematic cross-sectional views of the instrument 100 with the stiffening member 132 positioned at different points along the length L of the probe 110. Accordingly, FIGS. 2A and 2B are described herein in conjunction with FIG. 1 for clarity. The stiffening member 132 is an overall cylindrical and hollow tube that substantially surrounds the probe 110 at or near the proximal portion 112. Similar to the probe 110, the stiffening member 132 is formed of a material suitable for minimally invasive surgical procedures, such as vitreoretinal surgery, and other surgical procedures. In some embodiments, the stiffening member 132 is formed of a metallic material, such as surgical grade stainless steel, aluminum, or titanium. In other embodiments, the stiffening member 132 is formed of a composite material, such as a polymer composite material or a ceramic composite material.

[0017] Together with the probe 110, the stiffening member 132 is disposed through the opening 117 of the distal end portion 121 and has a proximal end portion 133 disposed within the internal chamber 124. The stiffening member 132 is sized to have an axial length sufficient to provide the probe 110 with the desired rigidity and stability, but a portion of it remains within the internal chamber 124 when the stiffening member assembly 130 is in an (e.g., fully) extended position. For example, the axial length of the stiffening member 132 can be from about 0.25 inches to about 1.75 inches, such as from about 0.30 inches to about 1.50 inches. For example, the axial length of the stiffening member 132 can be from about 0.50 inches to about 1.25 inches.

[0018] In one embodiment, the stiffening member 132 has a uniform outer diameter from the distal end portion 131 to the proximal end portion 133. By having a uniform outer diameter, a significant length of the stiffening member 132 can reciprocate through the opening 117 without forming a gap therebetween. However, other shapes and morphologies of the stiffening member 132 are also contemplated. For example, in some embodiments, the stiffening member 132 includes a square, rectangular, or polygonal tube. In further embodiments, the stiffening member 132 may have a non-uniform outer diameter. For example, the stiffening member 132 may have an outer diameter having one or more dimensions with a stepped or graduated delta.

[0019] The internal cavity 135 of the stiffening member 132 is sized not only to accommodate the outer diameter of the probe 110, but also to enable the stiffening member 132 to move easily along the probe 110. Therefore, the inner diameter or width of the stiffening member 132 is larger than the outer diameter of the probe 110 and allows for a slip fit. In one embodiment, the radial clearance between the stiffening member 132 and the probe 110 is from about 0.00020 inches to about 0.00060 inches, for example from about 0.00025 inches to about 0.00050 inches. For example, the radial clearance between the stiffening member 132 and the probe 110 is from about 0.00030 inches to about 0.00040 inches, for example about 0.00035 inches. Further, the internal dimensions of the stiffening member 132 are uniform from the distal end 131 to the proximal end 133, and the probe 110 can be uniformly stabilized throughout the internal cavity of the stiffening member 132.

[0020] In one embodiment, the stiffening member 132 is indirectly coupled to the control element 138 by the coupling arm 134 and the rod 136. The coupling arm 134 connects the stiffening member 132 to the rod 136 and is oriented non - parallel therebetween. In some embodiments, the coupling arm 134 is a direct extension from the stiffening member 132 and / or the rod 136. That is, the coupling arm 134 and the stiffening member 132 and / or the rod 136 are a single integral component. In other embodiments, the coupling arm 134 and the stiffening member 132 and / or the rod 136 are separate components that are coupled to each other by one or more coupling mechanisms and / or adhesives. For example, as shown in FIGS. 2A and 2B, the coupling arm 134 and the rod 136 are coupled together by a pin 137. In other examples, the coupling arm 134 and the rod 136 can be snap - fit together.

[0021] The control element 138 can be a button, knob, switch, toggle, or any other suitable device that can be actuated by a user. As shown in FIGS. 2A and 2B, the control element 138 is partially disposed within a linear channel 128 formed in the base unit 120. The channel 128 extends substantially parallel to the probe 110 and enables two-way sliding of the control element 138 along its longitudinal axis X. In one embodiment, the rod 136 is directly coupled to the control element 138 and extends substantially parallel to the probe 110 within the channel 128. The rod 136 can further be disposed through a second opening 119 formed in the distal end 121 of the base unit 120 for connection to the coupling arm 134. Generally, the rod 136 can be formed of metal or a composite material. In some embodiments, the rod 136 is formed of stainless steel, aluminum, or titanium. In other embodiments, the rod 136 is formed of a polymer composite material or a ceramic composite material.

[0022] In use, the rod 136 transmits the movement of the control element 138 to the coupling arm 134 and thus to the stiffening member 132. Accordingly, sliding of the control element 138 within the channel 128 causes sliding of the stiffening member 132 along the length L of the probe 110. In some embodiments, the stiffening member 132 is adjustable along the length L of the probe 110 by up to a distance of about 15 mm, for example up to a distance of about 10 mm along the length L of the probe 110. For example, the stiffening member 132 is adjustable along the length L of the probe 110 by up to a distance of about 5 mm.

[0023] In one embodiment, channel 128 includes a track having one or more protrusions 139 disposed at preset locations along the length of channel 128, and a control element 138 can be fixed to the protrusions. For example, the control element 138 may have grooves disposed on its lower surface or inclined surface and conforming to the morphology of the one or more protrusions 139. Therefore, the control element 138 can be locked to the protrusion 139 by sliding the adjacent control element 138 to engage the groove with the protrusion 139. As a result, the one or more protrusions 139 can be used to provide a predetermined level of rigidity to the probe 110. That is, the one or more protrusions 139 can be placed at preset increments along the length of channel 128 corresponding to the predetermined level of rigidity provided to the probe 110.

[0024] In another embodiment, channel 128 includes a track having a substantially planar surface, where the control element 138 can be slidably and dynamically actuated by the user, providing more flexibility and freedom to the user in determining the desired position of the stiffening member 132 relative to the probe 110. Thus, the user can set the control element 138 to a desired position by simply controlling the control element 138 with a thumb.

[0025] Figures 2A and 2B show a channel 128 in which three protrusions 139a - 139c are disposed. Generally, sliding the stiffening member 132 towards the distal end 116 of the probe 110 increases the rigidity of the probe 110. In Figure 2A, the stiffening member assembly 130 is disposed in a fully retracted position, where the control element 138 covers the upper side of the protrusion 139a and is locked in place. Accordingly, most of the stiffening member 132 is retracted within the base unit 120, reducing the stability and rigidity of the probe 110. In Figure 2B, the stiffening member assembly 130 is disposed in an extended position, where the control element 138 covers the upper side of the protrusion 139b and is locked in place. Accordingly, a larger portion of the stiffening member 132 extends over the proximal portion 112 of the probe 110, increasing the stability and rigidity of the probe 110.

[0026] The stiffening member assembly 130 is illustrated and described as having a control element 138, a coupling arm 134, and a rod 136, but these elements should not be considered limited thereto, as they include only one embodiment of the actuation mechanism for the stiffening member. Additional embodiments and forms of the actuation mechanism for the stiffening member are described further below.

[0027] FIG. 3 shows a perspective view of another exemplary instrument 300 having a stiffening member assembly 330. Instrument 300 is substantially similar to instrument 100, except for the structure and actuation mechanism of the stiffening member assembly 330. As shown in FIG. 3, the stiffening member assembly 330 includes a pinion 338 that is operably coupled to the proximal end of the stiffening member 332 (e.g., proximal end 333 described below) within an internal chamber 124 (shown in FIGS. 4A and 4B) to actuate the stiffening member 332 together with the probe 110.

[0028] FIGS. 4A and 4B show schematic cross-sectional views of an exemplary instrument 300 in which the stiffening member 332 is positioned at different points along the length L of the probe 110. Therefore, FIGS. 4A and 4B are described herein in conjunction with FIG. 3 for clarity.

[0029] As described above, stiffening member assembly 330 includes stiffening member 332 and pinion 338. Similar to stiffening member 132, stiffening member 332 is a substantially hollow tube that is slidably mounted on and surrounds probe 110. Together with probe 110, stiffening member 332 is disposed through opening 117 within base unit 120 and extends into its inner chamber 124. However, unlike stiffening member 132, stiffening member 332 includes a proximal end 333, on which a rack 336 is formed, and the rack engages pinion 338. In one embodiment, proximal end 333 is integrally coupled to its distal end 331. In another embodiment, proximal end 333 is removably coupled to distal end 331 by any suitable coupling mechanism and / or adhesive. Stiffening member 332 is sized to have an axial length sufficient to provide the desired rigidity and stability to probe 110 when stiffening member assembly 330 is in an (e.g., fully) extended position, including proximal end 333. For example, the axial length of stiffening member 332 can be from about 0.25 inches to about 1.75 inches, such as from about 0.30 inches to about 1.50 inches. For example, the axial length of stiffening member 132 can be from about 0.50 inches to about 1.25 inches.

[0030] Rack 336 includes a first plurality of linear gear teeth 334 formed on the outer surface of proximal end 333, and these linear gear teeth are operably coupled to a second plurality of teeth 335 formed on pinion 338. The linear pitch between each of the first plurality of linear gear teeth 334 depends on the diameter of pinion 338. In one example, the pitch between each of the first plurality of linear gear teeth 334 is from about 0.025 inches to about 0.25 inches, such as from about 0.05 inches to about 0.20 inches. For example, the pitch between each of the first plurality of linear gear teeth 334 is from about 0.075 inches to about 0.15 inches, such as from about 0.090 inches to about 0.10 inches. Generally, rack 336 is formed of metal or a composite material. In some embodiments, rack 336 is formed of stainless steel, aluminum, or titanium. In other embodiments, rack 336 is formed of a polymer composite or a ceramic composite.

[0031] The pinion 338 is disposed in a recess 337 (e.g., an opening) formed in the outer surface 122 of the base unit 120 such that a first portion of the pinion 338 projects outward from the recess 337 and away from the base unit 120 and is opposite to a second portion of the pinion 338 that engages with the rack 336 within the internal chamber 124. Similar to the rack 336, the pinion 338 is formed of metal or a composite material, such as stainless steel, aluminum, titanium, a polymer composite, or a ceramic composite. The recess 337 can be formed at any suitable location along the outer surface 122. For example, the recess 337 may be disposed adjacent to either the distal end 121 or the proximal end 125 of the base unit. In other embodiments, the recess 337 may be disposed more centrally between the distal end 121 and the proximal end 125.

[0032] In one embodiment, the pinion 338 is rotatably supported within the recess 337 by a pin 339 that is rotatably coupled to the base unit 120. Accordingly, rotation of the pinion 338 about an axis Z that is perpendicular to the longitudinal axis X linearly actuates the stiffening member 332 along the length L of the probe 110 in the first or second direction X1 and X2, respectively. For example, as shown in FIGS. 4A and 4B, rotation of the pinion 338 in the first rotational direction Y1 actuates the stiffening member 332 in the first linear direction X1 along the probe 110, thereby extending the stiffening member 332 out of the internal chamber 124 of the base unit 120 and increasing the stiffness of the probe 110. Conversely, rotation of the pinion 338 in the second rotational direction Y2 actuates the stiffening member 332 in the second linear direction X2 along the probe 110, and thus retracts the stiffening member 332 into the base unit 120 and decreases the stiffness of the probe 110. In some embodiments, the stiffening member 332 is adjustable up to a distance of about 15 mm along the length L of the probe 110, such as up to a distance of about 10 mm along the length L of the probe 110. For example, the stiffening member 332 is adjustable up to a distance of about 5 mm along the length L of the probe 110.

[0033] The stiffening member assembly 330 is illustrated and described as having a pinion 338 and a rack 336, but these elements should not be considered limited thereto, as they include only one embodiment of an operating mechanism for the stiffening member. Additional embodiments and forms of the operating mechanism for the stiffening member are further described throughout the present application.

[0034] FIG. 5 shows a perspective view of another exemplary instrument 500 according to one embodiment described herein. Instrument 500 is substantially similar to instruments 100 and 300, except for the structure and operating mechanism of the stiffening member assembly 530. As shown in FIG. 5, the stiffening member assembly 530 includes a rotatable distal end 538 movably coupled to a stiffening member 532 for actuating the stiffening member 532 along the probe 110.

[0035] FIGS. 6A and 6B show schematic cross-sectional views of an exemplary instrument 500 in which the stiffening member 532 is positioned at different points along the length L of the probe 110. Therefore, FIGS. 6A and 6B are described herein in conjunction with FIG. 5 for clarity.

[0036] As described above, the stiffening member assembly 530 includes a stiffening member 532 and a rotatable distal end 538. The distal end 538 is rotatably coupled to the base unit 120 and is configured to rotate about the longitudinal axis X through an opening 537. The distal end 538 is generally formed of metal or a composite material. In some embodiments, the distal end 538 is formed of stainless steel, aluminum, or titanium. In other embodiments, the distal end 538 is formed of a polymer composite or a ceramic composite.

[0037] Similar to stiffeners 132 and 332, stiffener 532 is an overall hollow tube that is slidably mounted on probe 110 and substantially surrounds the probe adjacent to proximal portion 112. Together with probe 110, stiffener 532 is disposed through an opening 537 provided at distal end 538 and extends into its inner chamber 124. Stiffener 532 is sized to have an axial length sufficient to provide the desired rigidity and stability to probe 110, but when the stiffener assembly 530 is in an (e.g., fully) extended position, a portion of it still extends through opening 537. For example, the axial length of stiffener 532 can be from about 0.25 inches to about 1.75 inches, such as from about 0.30 inches to about 1.50 inches. For example, the axial length of stiffener 132 can be from about 0.50 inches to about 1.25 inches.

[0038] Stiffener 532 has one or more features 535 formed on its outer surface 534. In one embodiment, feature 535 includes a helical thread. In another embodiment, feature 535 includes one or more protrusions and / or grooves formed on outer surface 534. The feature 535 of stiffener 532 is operatively coupled with one or more features 539 formed on the inner surface of opening 537. Similar to feature 535, feature 539 can include protrusions, grooves, and / or helical threads. However, at least one of opening 537 and outer surface 534 has a helical thread formed thereon. Generally, the feature 535 of stiffener 532 is a female engagement feature, and the feature 539 of opening 537 is a male engagement feature. However, it is also conceivable that feature 535 can be a male engagement feature and feature 539 can be a female engagement feature.

[0039] Accordingly, rotation of the distal end 538 about the longitudinal axis X linearly actuates the stiffening member 532 along the length L of the probe 110 in the first or second directions X1 and X2, respectively. For example, rotation of the distal end 538 in a first rotational direction about the longitudinal axis X can actuate the stiffening member 532 in a first linear direction X1 along the probe 110, thereby extending the stiffening member 532 from within the internal chamber 124 of the base unit 120 and increasing the rigidity of the probe 110. Conversely, rotation of the distal end 538 in a second rotational direction about the longitudinal axis X can actuate the stiffening member 532 in a second linear direction X2 along the probe 110, thereby retracting the stiffening member 532 into the base unit 120 and decreasing the rigidity of the probe 110. In some embodiments, the stiffening member 532 is adjustable up to a distance of about 15 mm along the length L of the probe 110, such as up to a distance of about 10 mm along the length L of the probe 110. For example, the stiffening member 532 is adjustable up to a distance of about 5 mm along the length L of the probe 110. It should be noted that in the embodiments described herein, at least a portion of the probe 110 (e.g., the distal portion 114) is inserted into the patient's eye through an insertion cannula. However, the remaining portion of the probe (e.g., the proximal portion 112) remains outside the eye and the insertion cannula. When (e.g., fully) extended, the stiffening members described herein cover the portion of the probe that remains outside the eye and the insertion cannula (or the hub of the insertion cannula).

[0040] The stiffening member assembly 530 is illustrated and described as having a rotatable distal end 538, but this element should not be considered limited thereto as it includes only one embodiment of an actuation mechanism for the stiffening member. Additional embodiments and forms of actuation mechanisms for the stiffening member are further described throughout the present application.

[0041] FIG. 7 shows a perspective view of another exemplary instrument 700 according to one embodiment described herein. Instrument 700 is substantially similar to instruments 100, 300, and 500, except for the structure and operating mechanism of the supplementary stiffening member assembly 730 (shown in FIGS. 8A and 8B). The supplementary stiffening member assembly 730 is a self-adjusting supplementary stiffening member assembly and includes a supplementary stiffening member 732 coupled to a biasing device 738. FIGS. 8A and 8B show schematic cross-sectional views of instrument 700 with the supplementary stiffening member 732 positioned at different points along the length L of the probe 110 and are therefore described together with FIG. 7 for clarity herein.

[0042] Similar to the supplementary stiffening members 132, 332, and 532 described above, the supplementary stiffening member 732 is an overall hollow tube that is slidably mounted on and substantially surrounds the probe 110 at the proximal portion 112. The supplementary stiffening member 732 is disposed through an opening 117 provided in the base unit 120 and extends into its internal chamber 124. In one embodiment, the supplementary stiffening member 732 includes an annular flange (e.g., flange 736) disposed at the proximal end (e.g., proximal end 733) within the internal chamber 124. In other embodiments, the flange 736 is disposed more axially along the length of the supplementary stiffening member 732. The flange 736 is configured to prevent the supplementary stiffening member 732 from sliding completely out of the base unit 120 through the opening 117. Therefore, the flange 736 serves the function of an anchor, which is one of its capabilities. In some embodiments, the flange 736 further provides a coupling surface between the supplementary stiffening member 732 and the biasing device 738.

[0043] The biasing device 738 applies a distal biasing force to the auxiliary rigid member 732 to push the auxiliary rigid member 732 toward the extended position P along the length L of the probe 110. Therefore, the auxiliary rigid member 732 will be continuously disposed at the extended position P unless an opposite proximal force is applied. During use, the probe 110 can be inserted into an insertion cannula having a hub (e.g., including a valve) at a desired depth selected by the user along the length L. When the distal end 731 of the auxiliary rigid member 732 reaches the hub of the insertion cannula, the user can further push the instrument 700 toward the hub to carry the probe 110 deeper inside. By applying a force to the hub that is greater than the force provided by the biasing device 738, the auxiliary rigid member 732 is retracted into the base unit 120 (shown in FIG. 8B) to allow a larger portion of the probe 110 to enter the eye. Thus, a maximum amount of support is continuously applied to the probe 110 by the auxiliary rigid member 732, but the probe 110 is the only component of the cannula and the instrument entering the eye. Therefore, no manual adjustment is required to adjust the position of the auxiliary rigid member 732, and optimal rigidity or stiffness is provided to the probe 110 at all times.

[0044] In some embodiments, the auxiliary rigid member 732 is adjustable along the length L of the probe 110 by up to about 10 mm, such as up to about 6 mm along the length L of the probe 110. For example, the auxiliary rigid member 732 is adjustable along the length L of the probe 110 by up to about 3 mm.

[0045] In one embodiment, the biasing device 738 is actuated by a spring 739, such as a compression spring. For example, the biasing device 738 can be actuated by a coil, i.e., a helical spring. In other examples, the biasing device 738 can include a spring configuration other than a coil. In one embodiment, the biasing device 738 is actuated by a compressible and foamable polymer or elastomeric material. In yet another embodiment, the biasing device is actuated by a pneumatic or hydraulic piston.

[0046] Although the stiffening member assembly 730 is illustrated and described as having a biasing device 738, this element should not be considered limited thereto, as it includes only one embodiment of an actuating mechanism for the stiffening member. Additional embodiments and forms of the actuating mechanism for the stiffening member are further described throughout the present application.

[0047] In summary, embodiments of the present disclosure include structures and mechanisms for adjusting the stiffness of microsurgical instruments, such as small instruments for minimally invasive ophthalmic surgery. The instruments described above include a plurality of embodiments in which a user, such as a surgeon, can adjust the stiffness of the instrument while using the instrument. Thus, the described embodiments expand the applicability of smaller instruments to a wider range of applications so that a surgeon can access a wider range of tissues using a single instrument.

[0048] In one example, the described embodiments enable a surgeon to dynamically adjust the stiffness and length of a vitrectomy probe to access all regions of the vitreous cavity during a single procedure. Adjustment of the probe can be performed before inserting the probe into the eye or after the probe has already been inserted therein. Therefore, the described embodiments can be used to facilitate access to the posterior segment of the eye during vitreous surgery, while maintaining the benefits of smaller gauge probes, such as improved patient comfort, reduced conjunctival scarring, reduced postoperative inflammation, and reduced healing time. Vitreous surgery is described as an example of a surgical procedure that can benefit from the embodiments described, but the advantages of an instrument with adjustable stiffness also provide benefits to other surgical procedures.

[0049] The foregoing relates to embodiments of the present disclosure, but other and further embodiments of the present disclosure may be devised without departing from its basic scope, which is determined by the following claims.

Claims

1. a base unit configured to be held by a user; a probe disposed through a first opening in a distal end of the base unit, the probe having a length parallel to a longitudinal axis thereof; 1. A stiffener assembly comprising: a stiffener disposed through the first opening in the base unit, the stiffener being formed of a hollow tubular member slidably coupled to and surrounding at least a portion of the probe; and an actuation mechanism configured to move the stiffener along the length of the probe; a stiffener assembly including: including surgical instruments.

2. The surgical instrument of claim 1 , wherein the stiffness of the probe is increased by sliding the stiffener out of the base unit toward the distal end of the probe.

3. 3. The surgical instrument of claim 2, wherein the actuation mechanism includes a control member coupled to the stiffener, the control member being partially disposed within a linear channel formed in the base unit and parallel to the probe, and moving the control member along the linear channel moves the stiffener along the length of the probe.

4. The stiffener assembly comprises: a rod coupled to the control member and parallel to the linear channel, the rod being further disposed through a second opening in the base unit; a linkage arm connecting the rod to the stiffener external to the base unit, the linkage arm being oriented non-parallel to the length of the probe, and wherein moving the control member along the linear channel actuates the rod and the linkage arm, and actuating the rod and the linkage arm moves the stiffener along the length of the probe; and The surgical instrument of claim 3 further comprising:

5. The surgical instrument of claim 4 , wherein the rod is coupled to the linkage arm by a pin at its distal end.

6. The surgical instrument of claim 5 , wherein the control member is a button, knob, switch, or toggle slidably coupled to the base unit.

7. 4. The surgical instrument of claim 3, wherein the linear channel includes a track with one or more protrusions disposed at predetermined locations along a length of the linear channel, the one or more protrusions configured to engage grooves formed in a surface of the control member and corresponding to a predetermined level of stiffness imparted to the probe.

8. The surgical instrument of claim 3 , wherein the linear channel includes one or more substantially planar surfaces along which the control member is configured to dynamically slide.

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