Adjustable stiffeners 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, entitled "ADJUSTABLE STIFFENER FOR SURGICAL INSTRUMENTS", with inventors Bill Chen, James Y. Chon and John R. Underwood, the entire content of which is incorporated herein by reference as if fully and completely set forth in the present specification. BACKGROUND ART

[0002] Continuing efforts to minimize the invasiveness of surgical procedures, such as ophthalmic surgery, have led to the development of compact surgical instruments for micro-incision techniques. Compact vitrectomy, also known as minimally invasive vitreous surgery (MIVS), is a typical example of one such type of surgical procedure using compact instruments. Examples of common ocular conditions that can be treated by minimally invasive vitreous surgery include retinal detachment, macular hole, epimacular fibrosis, and vitreous hemorrhage. Compared with more invasive vitrectomy procedures, the benefits associated with modern MIVS include, inter alia, access to larger lesions, higher fluid stability, improved patient comfort, reduced conjunctival scarring, reduced post-operative inflammation, and earlier visual recovery. Accordingly, the indications for MIVS and other micro-incision techniques have expanded in recent years.

[0003] Despite the aforementioned benefits of microincision techniques and their widespread support, several challenges remain in the use of small surgical instruments, particularly in the field of ophthalmology. One concern frequently mentioned among surgeons is instrument rigidity. The smaller the diameter of these microincision instruments, such as vitrectomy probes, the lower their stiffness, making it difficult for surgeons to control the instruments during certain eye surgical procedures. With small ophthalmic surgical instruments, for example, the tip of the instrument may move in an unintended direction at either side of the eye, thus making delicate procedures, such as detaching membranes from the retinal surface, extremely difficult. [Overview of the project] [Problems that the invention aims to solve]

[0004] Therefore, improvements in minimally invasive ophthalmic surgical techniques and the equipment used for them are needed in this field. [Means for solving the problem]

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

[0006] To provide a more detailed understanding of the features of this disclosure listed above, a more detailed description of the disclosure, which is briefly summarized above, can be obtained by referring to 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 limiting in scope, as other similarly effective embodiments may be found. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows a perspective view of an exemplary instrument according to one embodiment of the present disclosure. [Figure 2A] Figure 2A shows a schematic longitudinal cross-sectional view of the instrument shown in Figure 1. [Figure 2B] Figure 2B shows another schematic longitudinal section of the instrument shown in Figure 1. [Figure 3] Figure 3 shows a perspective view of an exemplary instrument according to one embodiment of the present disclosure. [Figure 4A] Figure 4A shows a schematic longitudinal cross-sectional view of the device shown in Figure 3. [Figure 4B] Figure 4B shows another schematic longitudinal section of the instrument shown in Figure 3. [Figure 5] Figure 5 shows a perspective view of an exemplary instrument according to one embodiment of the present disclosure. [Figure 6A] Figure 6A shows a schematic longitudinal cross-sectional view of the instrument shown in Figure 5. [Figure 6B] Figure 6B shows another schematic longitudinal section of the instrument shown in Figure 5. [Figure 7] Figure 7 shows a perspective view of an exemplary instrument according to one embodiment of the present disclosure. [Figure 8A] Figure 8A shows a schematic longitudinal cross-sectional view of the device shown in Figure 7. [Figure 8B] Figure 8B shows another schematic longitudinal section of the instrument shown in Figure 7. [Modes for carrying out the invention]

[0008] For ease of understanding, the same reference numerals are used to indicate the same elements common to multiple drawings, where possible. Elements and features of one embodiment may be usefully incorporated into other embodiments without further description.

[0009] This disclosure relates, in general, to microsurgical instruments with variable stiffness, and more particularly to microsurgical instruments with variable stiffness for ophthalmic surgery. In one embodiment, the surgical instrument includes a probe and a stiffener assembly. The stiffener assembly further includes a stiffener formed of a hollow tubular member substantially enclosing at least a portion of the length of the probe. The stiffness of the probe is adjusted by the action of the stiffener along the length of the probe, and therefore the user is able to better control the surgical instrument.

[0010] Figure 1 shows a perspective view of an exemplary instrument 100 according to one embodiment described herein. As shown in Figure 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 distally at a distal end 116. In some embodiments, the proximal portion 112 extends through a substantial portion of the internal chamber (124, shown in Figures 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 a vitrectomy, which may be suction-assisted or non-suction-assisted. The probe 110 may include a hollow tube with a diameter of less than about 20 gauge. For example, the diameter of the probe 110 is less than about 23 gauge, for example, less than about 25 gauge. In one embodiment, the diameter of the probe 110 is approximately 27 gauge. In further examples, the probe 110 may include an illumination device, a laser guide, an suction device, forceps, scissors, a traction device, or other suitable devices that are placed inside or coupled thereto.

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

[0013] The probe 110 is positioned partially and longitudinally through the distal end 121 of the base unit 120 adjacent to the proximal portion 112, and can be directly or indirectly attached thereto within the 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 may be contoured to substantially fit the user's hand. In some embodiments, the outer surface 122 may be textured or have one or more gripping features formed thereon, such as one or more grooves and / or ridges.

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

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

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

[0017] Together with the probe 110, the stiffener 132 is disposed through the opening 117 at the distal end 121 and has a proximal end 133 disposed within the inner chamber 124. The stiffener 132 is sized to have an axial length sufficient to provide the probe 110 with desired rigidity and stability, while a portion thereof still remains within the inner chamber 124 when the stiffener assembly 130 is in, for example, a fully extended position. For example, the axial length of the stiffener 132 may be about 0.25 inches to about 1.75 inches, such as about 0.30 inches to about 1.50 inches. For example, the axial length of the stiffener 132 may be about 0.50 inches to about 1.25 inches.

[0018] In one embodiment, the stiffener 132 has a uniform outer diameter from the distal end 131 to the proximal end 133. The uniform outer diameter allows a substantial length of the stiffener 132 to reciprocate through the opening 117 without forming a gap therebetween. However, other shapes and morphologies of the stiffener 132 are also contemplated. For example, in some embodiments, the stiffener 132 comprises a square, rectangular, or polygonal tube. In further embodiments, the stiffener 132 may have a non-uniform outer diameter. For example, the stiffener 132 may have an outer diameter with one or more dimensions followed by a stepped or gradual delta.

[0019] The internal cavity 135 of the stiffener 132 is not only sized to accommodate the outer diameter of the probe 110, but also configured to allow the stiffener 132 to be easily moved along the probe 110. Therefore, the inner diameter or width of the stiffener 132 is larger than the outer diameter of the probe 110 and enables a sliding fit. In one embodiment, the radial clearance between the stiffener 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 stiffener 132 and the probe 110 is from about 0.00030 inches to about 0.00040 inches, for example about 0.00035 inches. Furthermore, the inner dimension of the stiffener 132 is uniform from the distal end 131 to the proximal end 133, which can uniformly stabilize the probe 110 throughout the internal cavity of the stiffener 132.

[0020] In one embodiment, the stiffener 132 is indirectly coupled to the control element 138 by the coupling arm 134 and the rod 136. The coupling arm 134 connects the stiffener 132 to the rod 136 and is oriented non-parallel therebetween. In some embodiments, the coupling arm 134 is a direct extension from the stiffener 132 and / or the rod 136. That is, the coupling arm 134 and the stiffener 132 and / or the rod 136 are a single integral component. In other embodiments, the coupling arm 134 and the stiffener 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 another example, the coupling arm 134 and the rod 136 may be snap-fitted together.

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

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

[0023] In one embodiment, the channel 128 includes a track having one or more projections 139 positioned at predetermined locations along the length of the channel 128, to which control elements 138 can be fixed. For example, a control element 138 may have a groove positioned on its underside or inclined surface and conforming to the morphology of one or more projections 139. Thus, a control element 138 can be locked to a projection 139 by sliding an adjacent control element 138 to engage the groove with the projection 139. As a result, one or more projections 139 can be used to provide a predetermined level of stiffness to the probe 110. That is, one or more projections 139 may be placed in predetermined increments along the length of the channel 128 corresponding to the predetermined level of stiffness to be provided to the probe 110.

[0024] In another embodiment, the channel 128 includes a track that is substantially planar, where the control element 138 can be slidably and dynamically actuated by the user, giving the user greater flexibility and freedom in determining the desired position of the stiffener 132 relative to the probe 110. Thus, the user can set the control element 138 to the desired position simply by controlling the control element 138 with their thumb.

[0025] Figures 2A and 2B show a channel 128 in which three projections 139a to 139c are located. Generally, the rigidity of the probe 110 is increased by sliding the stiffener 132 toward the distal end 116 of the probe 110. In Figure 2A, the stiffener assembly 130 is positioned in a fully retracted position, where the control element 138 covers the upper side of projection 139a and locks in place. Thus, most of the stiffener 132 is retracted into the base unit 120, reducing the stability and rigidity of the probe 110. In Figure 2B, the stiffener assembly 130 is positioned in an extended position, where the control element 138 covers the upper side of projection 139b and locks in place. Thus, a larger portion of the stiffener 132 extends across the proximal portion 112 of the probe 110, increasing the stability and rigidity of the probe 110.

[0026] The stiffener 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 limiting as they represent only one embodiment of the actuation mechanism for the stiffener. Additional embodiments and forms of the actuation mechanism for the stiffener are further described below.

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

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

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

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

[0031] The pinion 338 is positioned 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 protrudes from the recess 337 toward the outside of the base unit 120 and is directly opposite to a second portion of the pinion 338 that engages with the rack 336 within the internal chamber 124. Like the rack 336, the pinion 338 is formed of a metal or composite material, such as stainless steel, aluminum, titanium, polymer composite, or ceramic composite. The recess 337 can be formed at any preferred location along the outer surface 122. For example, the recess 337 may be positioned adjacent to either the distal end 121 or the proximal end 125 of the base unit. In other embodiments, the recess 337 may be positioned 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. Thus, the rotation of the pinion 338 around an axis Z perpendicular to the longitudinal axis X linearly acts the stiffener 332 along the length L of the probe 110 in first or second directions X1 and X2, respectively. For example, as shown in Figures 4A and 4B, the rotation of the pinion 338 in the first rotational direction Y1 acts the stiffener 332 along the probe 110 in the first linear direction X1, thereby extending the stiffener 332 from within the internal chamber 124 of the base unit 120 and increasing the rigidity of the probe 110. Conversely, the rotation of the pinion 338 in the second rotational direction Y2 acts the stiffener 332 along the probe 110 in the second linear direction X2, thus retracting the stiffener 332 into the base unit 120 and reducing the rigidity of the probe 110. In some embodiments, the stiffener 332 is adjustable to a distance of about 15 mm along the length L of the probe 110, for example, to a distance of about 10 mm along the length L of the probe 110. For example, the stiffener 332 is adjustable to a distance of about 5 mm along the length L of the probe 110.

[0033] The stiffener assembly 330 is illustrated and described as having a pinion 338 and a rack 336, but these elements should not be considered limiting as they represent only one embodiment of the actuation mechanism for the stiffener. Additional embodiments and forms of the actuation mechanism for the stiffener are described further throughout this application.

[0034] Figure 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 stiffener assembly 530. As shown in Figure 5, the stiffener assembly 530 includes a rotatable distal end 538 that is movably coupled to the stiffener 532 in order to operate the stiffener 532 along the probe 110.

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

[0036] As described above, the stiffener assembly 530 includes a stiffener 532 and a rotatable distal end 538. The distal end 538 is rotatably coupled to the base unit 120 and is configured to rotate around the longitudinal axis X through an opening 537. The distal end 538 is generally formed of a metal or 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 ceramic composite material.

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

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

[0039] Therefore, rotation of the distal end 538 around the longitudinal axis X linearly acts the stiffener 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 the first rotational direction around the longitudinal axis X can actuate the stiffener 532 along the probe 110 in the first linear direction X1, thereby extending the stiffener 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 the second rotational direction around the longitudinal axis X can actuate the stiffener 532 along the probe 110 in the second linear direction X2, thereby retracting the stiffener 532 into the base unit 120 and decreasing the rigidity of the probe 110. In some embodiments, the stiffener 532 is adjustable to a distance of about 15 mm along the length L of the probe 110, for example, to a distance of about 10 mm along the length L of the probe 110. For example, the stiffener 532 is adjustable to a distance of about 5 mm along the length L of the probe 110. Note 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 fully extended (e.g., fully), the stiffener described herein covers the portion of the probe that remains outside the eye and the insertion cannula (or the hub of the insertion cannula).

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

[0041] Figure 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 stiffener assembly 730 (shown in Figures 8A and 8B). The stiffener assembly 730 is a self-adjusting stiffener assembly and includes a stiffener 732 coupled to a biasing device 738. Figures 8A and 8B show schematic cross-sectional views of instrument 700 in which the stiffener 732 is positioned at different points along the length L of the probe 110, and are therefore described herein together with Figure 7 for clarity.

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

[0043] The biasing device 738 applies a distal biasing force to the stiffener 732 to push it toward a position P extended along the length L of the probe 110. Therefore, unless a proximal force is applied, the stiffener 732 remains continuously positioned at the extended position P. During use, the probe 110 can be inserted into an insertion cannula equipped with a hub (e.g., including a valve) along its length L to a desired depth selected by the user. Once the distal end 731 of the stiffener 732 reaches the hub of the insertion cannula, the user can further push the instrument 700 toward the hub to advance the probe 110 deeper inside. By applying a force greater than that provided by the biasing device 738 to the hub, the stiffener 732 can be retracted into the base unit 120 (as shown in Figure 8B), allowing a larger portion of the probe 110 to enter the eye. Therefore, the stiffener 732 continuously provides maximum support to the probe 110, but the probe 110 is the only component of the cannula and the instrument 700 that enters the eye. Thus, no manual adjustment is required to adjust the position of the stiffener 732, and the probe 110 is always provided with optimal rigidity or stiffness.

[0044] In some embodiments, the stiffener 732 is adjustable to a distance of approximately 10 mm along the length L of the probe 110, for example, to a distance of approximately 6 mm along the length L of the probe 110. For example, the stiffener 732 is adjustable to a distance of approximately 3 mm along the length L of the probe 110.

[0045] In one embodiment, the biasing device 738 is actuated by a spring 739, for example, a compression spring. For example, the biasing device 738 may be actuated by a coil, i.e., a helical spring. In other examples, the biasing device 738 may include spring forms other than coils. In one embodiment, the biasing device 738 is actuated by a compressible and foaming polymer or elastomer material. In yet another embodiment, the biasing device is actuated by a pneumatic or fluid-pressure piston.

[0046] The stiffener assembly 730 is illustrated and described as having a biasing device 738, but this element should not be considered limiting as it includes only one embodiment of the actuation mechanism for the stiffener. Additional embodiments and forms of the actuation mechanism for the stiffener are described further throughout this 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 several embodiments in which a user, such as a surgeon, can adjust the stiffness of the instrument while using it. Thus, the described embodiments extend the applicability of smaller instruments to a wider range of applications, enabling surgeons to access a wider area of ​​tissue with a single instrument.

[0048] In one example, the described embodiment allows a surgeon to dynamically adjust the stiffness and length of a vitrectomy probe to access the entire area of ​​the vitreous cavity during a single procedure. Probe adjustment can be performed before inserting the probe into the eye or after it has already been inserted. Therefore, while the described embodiment can be used to facilitate access to the posterior segment of the eye during vitrectomy, it retains the benefits of smaller gauge probes, such as improved patient comfort, reduced conjunctival scarring, decreased postoperative inflammation, and shorter healing times. Vitrectomy is described as an example of a surgical procedure that may benefit from the described embodiment, but the advantages of an instrument with adjustable stiffness also benefit 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, the scope of which is determined by the following claims. This disclosure also includes the following aspects: [Aspect 1] A base unit configured to be held by the user, A probe positioned through a first opening provided at the distal end of the base unit, the probe having a length parallel to its longitudinal axis, A stiffening assembly: A stiffening member disposed through the first opening provided in the base unit, the stiffening member being formed of a hollow tubular member that is slidably coupled to the probe and surrounds at least a portion thereof, and An operating mechanism configured to move the stiffener along the length of the probe Including a stiffening assembly and Surgical instruments, including those mentioned above. [Aspect 2] The surgical instrument according to embodiment 1, wherein the rigidity of the probe is increased by sliding the stiffening member toward the distal end of the probe outside the base unit. [Aspect 3] The surgical instrument according to embodiment 2, wherein the operating mechanism includes a control member coupled to the stiffener, the control member is partially positioned within a linear channel formed in the base unit and is parallel to the probe, and the stiffener is moved along the length of the probe by moving the control member along the linear channel. [Aspect 4] The aforementioned stiffening assembly is: A rod coupled to the control member and parallel to the linear channel, further arranged through a second opening provided in the base unit, A coupling arm that connects the rod to the stiffener outside the base unit, wherein the coupling arm is oriented non-parallel to the length of the probe, and by moving the control member along the linear channel, the rod and the coupling arm are actuated, and by acting the rod and the coupling arm, the stiffener is moved along the length of the probe, and The surgical instrument according to embodiment 3, further including the following: [Aspect 5] The surgical instrument according to embodiment 4, wherein the rod is connected to the connecting arm by a pin at its distal end. [Aspect 6] The surgical instrument according to embodiment 5, wherein the control member is a button, knob, switch, or toggle that is slidably coupled to the base unit. [Aspect 7] The surgical instrument according to embodiment 3, wherein the linear channel includes a track in which one or more projections are positioned at predetermined locations along the length of the linear channel, the one or more projections are configured to engage with grooves formed on the surface of the control member, and the linear channel corresponds to a predetermined level of stiffness to be provided to the probe. [Aspect 8] The surgical instrument according to embodiment 3, wherein the linear channel includes one or more substantial planes on which the control member is configured to slide dynamically. [Aspect 9] The surgical instrument according to embodiment 1, wherein the operating mechanism includes a biasing device that applies a biasing force to the stiffener in the distal direction. [Aspect 10] The surgical instrument according to embodiment 9, wherein the stiffening member is retracted into the base unit by applying a force in the opposite direction in the proximal direction. [Aspect 11] The surgical instrument according to embodiment 10, wherein the biasing device includes a compression spring. [Aspect 12] The aforementioned operating mechanism is: A rack connected to the stiffener, which is located inside the base unit and has a first set of teeth formed on it, A pinion disposed in a recess formed on the outer surface of the base unit, wherein the pinion has a second set of teeth operably coupled to a first set of teeth formed on the rack, and the rotation of the pinion causes the stiffener to slide along the length of the probe. A surgical instrument according to embodiment 1, including the above. [Aspect 13] The surgical instrument according to embodiment 12, wherein the pinion includes a first portion that protrudes from the recess to the outside of the base unit and a second portion that engages with the rack within the internal chamber, the first portion and the second portion being diametrically opposed to each other. [Aspect 14] The surgical instrument according to embodiment 13, wherein the stiffener is moved linearly along the length of the probe by rotating the pinion around an axis perpendicular to the longitudinal axis. [Aspect 15] The operating mechanism includes a nose member coupled to the base unit, the nose member being rotatable about the longitudinal axis, and the nose member having one or more first features formed on its inner surface. The probe extends from the internal chamber of the base unit through an opening provided in the nose member, and the first opening includes the opening provided in the nose member, and The stiffening member extends from the internal chamber of the base unit through the opening provided in the nose member, and the stiffening member is: A first section is positioned through the opening provided in the nose member and extends to the outside of the base unit, A second section located within the interior chamber of the base unit, the second section having one or more second features formed on its outer surface, the one or more second features being operably coupled to the one or more first features of the nose member, and The surgical instrument according to embodiment 1, further comprising: [Aspect 16] The surgical instrument according to embodiment 15, wherein the stiffener moves linearly along the length of the probe by rotating the rotatable nose about its longitudinal axis. [Aspect 17] The surgical instrument according to embodiment 16, wherein one or more of the first features or one or more of the second features include a helical screw thread.

Claims

1. A base unit configured to be held by the user, A probe positioned through a first opening provided at the distal end of the base unit, the probe having a length parallel to its longitudinal axis, A stiffening assembly: A stiffening member disposed through the first opening provided in the base unit, the stiffening member being formed of a hollow tubular member that is slidably coupled to the probe and surrounds at least a portion thereof, An operating mechanism comprising a control member coupled to the stiffener, configured to move the stiffener along the length of the probe, A rod coupled to the control member, the rod being arranged parallel to the probe through a second opening provided in the base unit, and A coupling arm that connects the rod to the distal end of the stiffener outside the base unit, wherein the coupling arm is oriented non-parallel to the length of the probe, Includes, In a fully retracted position, the majority of the hollow tubular member is retracted into the base unit. The control member is partially positioned within a linear channel formed in the base unit and is parallel to the probe. By moving the control member along the linear channel, the rod and the coupling arm are activated. By operating the rod and the connecting arm, the stiffener assembly moves the stiffener along the length of the probe. Surgical instruments, including those mentioned above.

2. The surgical instrument according to claim 1, wherein the rigidity of the probe is increased by sliding the stiffening member toward the distal end of the probe outside the base unit.

3. The surgical instrument according to claim 1, wherein the rod is connected to the connecting arm by a pin at its distal end.

4. The surgical instrument according to claim 3, wherein the control member is a button, knob, switch, or toggle that is slidably coupled to the base unit.

5. The surgical instrument according to claim 1, wherein the linear channel includes a track in which one or more projections are positioned at predetermined locations along the length of the linear channel, the one or more projections are configured to engage with grooves formed on the surface of the control member, and the linear channel corresponds to a predetermined level of stiffness to be provided to the probe.

6. The surgical instrument according to claim 1, wherein the linear channel includes one or more substantial planes on which the control member is configured to slide dynamically.

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