Adjustable stiffener for surgical instruments

A surgical instrument includes a base unit, a probe, a stiffener, and an actuation mechanism. The stiffener is formed of a hollow tubular member substantially surrounding at least a portion of a length of the probe. The actuation mechanism is configured to actuate the stiffener along the length of the probe and adjust the stiffness of the probe, thus providing a user better control of the surgical instrument. The actuation mechanism includes a stiffener biasing device configured to apply a first biasing force against the stiffener in the distal direction and, in some embodiments, a control member configured to lock the stiffener in a position along the length of the probe.

BACKGROUND

Field

Embodiments of the present disclosure generally relate to small-gauge instrumentation for surgical procedures, and more particularly, small-gauge instrumentation for ophthalmic surgical procedures.

Description of the Related Art

Continuous efforts to minimize the invasiveness of surgical procedures, such as ophthalmic surgical procedures, have led to the development of small-gauge surgical instrumentation, which are referred to as microsurgical instruments, for microincision techniques. Small gauge vitrectomy, also known as minimally invasive vitreous surgery (MIVS), is a classic example of one such type of surgical procedure utilizing small-gauge instrumentation. Examples of common ocular conditions that may be treated by minimally invasive vitreous surgery include retinal detachment, macular holes, premacular fibrosis, and vitreous hemorrhages. The benefits associated with modern MIVS as compared to more invasive vitrectomies include access to greater pathology, greater fluidic stability, increased patient comfort, less conjunctival scarring, less postoperative inflammation, and earlier visual recovery, among others. Accordingly, indications for MIVS and other microincision techniques have expanded in recent years.

Despite the aforementioned benefits of microincision techniques and their widespread acceptance, there remain numerous challenges with the utilization of small-gauge surgical instruments, particularly in the field of ophthalmology. One commonly noted concern among surgeons is instrument rigidity. The smaller diameter of these microincision instruments, such as vitrectomy probes, causes decreased stiffness thereof, making it difficult for surgeons to control the instruments during certain ocular surgical procedures. With small-gauge ophthalmic surgical instruments, for example, the instrument tips can move in unintended directions at the extreme limits of the eye, thus making delicate procedures such as the peeling of membranes from the retinal surface extremely difficult.

Accordingly, what is needed in the art are improved methods and apparatus for minimally-invasive ophthalmic surgical procedures.

SUMMARY

The present disclosure generally relates to surgical instruments, and more particularly, microsurgical instruments for ophthalmic surgical procedures.

In certain embodiments, a surgical instrument is provided that includes a base unit and a probe. The base unit is configured to be held by a user. The probe is disposed through a base unit opening in a distal end of the base unit and has a length parallel to a probe longitudinal axis thereof. The surgical instrument further includes a stiffener extending through the base unit opening in the base unit and an actuation mechanism configured to actuate the stiffener along the length of the probe in a distal direction. The stiffener is formed of a hollow tubular member that surrounds at least a portion of the probe and is slidably coupled thereto. The actuation mechanism includes a stiffener biasing device configured to apply a first biasing force against the stiffener in the distal direction. In some embodiments, the actuation mechanism further includes a control member configured to lock the stiffener in position.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of certain embodiments may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

In the following description, details are set forth by way of example to facilitate an understanding of the disclosed subject matter. It should be apparent to a person of ordinary skill in the art, however, that the disclosed implementations are exemplary and not exhaustive of all possible implementations. Thus, it should be understood that reference to the described examples is not intended to limit the scope of the disclosure. Any alterations and further modifications to the described devices, instruments, 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 features, components, and/or steps described with respect to one implementation may be combined with the features, components, and/or steps described with respect to other implementations of the present disclosure.

Note that, as described herein, a distal end, segment, or portion of a component refers to the end, segment, or portion that is closer to a patient's body during use thereof. On the other hand, a proximal end, segment, or portion of the component refers to the end, segment, or portion that is distanced further away from the patient's body. An intermediate segment or portion of a component refers to the segment or portion that is positioned between the distal segment or portion and the proximal end or portion.

As used herein, the term “about” may refer to a +/−10% variation from the nominal value. It is to be understood that such a variation can be included in any value provided herein.

The present disclosure generally relates to surgical instruments, such as microsurgical instruments having variable stiffness, and more particularly, microsurgical instruments having variable stiffness for ophthalmic surgical procedures (e.g., vitrectomy probes, illuminator probes, etc.) In certain embodiments, a microsurgical instrument includes a probe and a stiffener. The stiffener may be 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 providing a user better control of the microsurgical instrument. The stiffener may include a de-coupler and, in some embodiments, may be locked or maintained at different positions along the length of the probe through the interaction of the de-coupler and a control member. In some embodiments, the de-coupler may de-couple the stiffener from a biasing spring without a control member. In some embodiments, using a stiffener locking mechanism may allow the user to set and “lock-in” the stiffness of the microsurgical instrument to a desired level.

FIG.1Aillustrates a perspective view of a vitrectomy probe100with a dynamically adjustable stiffening sleeve132, according to certain embodiments. As depicted inFIG.1A, the instrument100comprises a probe110or needle (referred to hereinafter as a “probe”) and a base unit120. The probe110includes a proximal portion112and a distal portion114which terminates distally at a distal end116. In some embodiments, the proximal portion112extends through a substantial portion of an interior chamber (e.g., an interior chamber124inFIGS.2,4A, and4B) of the base unit120.

In one example, the probe110is an elongated cutting member of a vitrectomy probe. For example, the probe110, which may be aspirating or non-aspirating, may be inserted into a cannula for performance of vitreous surgery. The probe110may comprise a hollow tube having, e.g., a diameter less than about 20 gauge. For example, the probe110has a diameter less than about 23 gauge, such as a diameter less than about 25 gauge. In certain embodiments, the probe110has a diameter of approximately 27 gauge. In further examples, the probe110may include an illumination device (e.g., as seen inFIGS.3A-3B), a laser guide, a suction device, forceps, scissors, retractors, or other suitable devices disposed therein or coupled thereto.

Generally, the probe110is formed of a material suitable for minimally invasive surgical procedures, such as vitreoretinal surgeries that involve removal of the vitreous in the eye, or other surgical procedures. For example, the probe110is formed of surgical grade stainless steel, aluminum, or titanium.

The probe110is partially and longitudinally disposed through a distal end121of the base unit120adjacent the proximal portion112of the probe110and may be directly or indirectly attached thereto within the interior chamber124of the base unit120. In certain embodiments, the base unit120is a handpiece having an outer surface122configured to be held by a user, such as a surgeon. For example, the base unit120may be contoured to substantially fit the hand of the user. In some embodiments, the outer surface122may be textured or have one or more gripping features formed thereon, such as one or more grooves and/or ridges.

In certain embodiments, the base unit120may house at least a portion of a drive mechanism operable to reciprocate the probe110within and relative to the base unit120. In one example, the drive mechanism may be a pneumatic drive mechanism including a diaphragm. The base unit120may further provide one or more ports123at a proximal end125thereof for one or more supply lines to be routed into the interior chamber124. For example, the one or more ports123may provide a connection between the base unit120and a vacuum source for aspiration. In another example, the one or more ports123provide a connection to a pneumatic, hydraulic, or electrical power source to operate the drive mechanism, an illumination device, a laser, or other suitable device within or coupled to the base unit120.

The instrument100further includes a stiffener132slidably coupled to and substantially surrounding at least a portion of the probe110. The stiffener132is adjustable relative to the probe110, enabling a user to position the stiffener132(e.g., a distal end131of the stiffener132) at different points along a length L of the probe110exterior to the base unit120.

In some embodiments the stiffener132is generally a cylindrical and hollow tube substantially surrounding the probe110at or near the proximal portion112. Similar to the probe110, the stiffener132is formed of a material suitable for minimally invasive surgical procedures, such as vitreoretinal surgeries and other surgical procedures. In some embodiments, the stiffener132is formed of a metallic material, such as surgical grade stainless steel, aluminum, or titanium. In other embodiments, the stiffener132is formed of a composite material, such as a polymer composite material or a ceramic composite material.

As seen inFIG.2andFIGS.4A-4B, an inner cavity135of the stiffener132is sized to accommodate an outer diameter of the probe110while also permitting the stiffener132to be readily moved along the probe110. Thus, an inner diameter or width of the stiffener132is greater than the outer diameter of the probe110and enables a sliding fit. In one embodiment, a radial clearance between the stiffener132and the probe110is between about 0.00020 inches and about 0.00060 inches, such as between about 0.00025 inches and about 0.00050 inches. For example, the radial clearance between the stiffener132and the probe110is between about 0.00030 inches and about 0.00040 inches, such as about 0.00035 inches. Further, the inner dimensions of the stiffener132may be uniform from the distal end131to the proximal end133to enable uniform stabilization of the probe110throughout the inner cavity of the stiffener132.

Along with the probe110, the stiffener132is disposed through the base unit opening117of the distal end121of the base unit120and has a proximal end133disposed in the interior chamber124of the base unit120. As shown, the stiffener132includes an annular flange (e.g., flange136) disposed at its proximal end133within the interior chamber124. In other embodiments, the flange136is disposed more axially along a length of the stiffener132. The flange136is configured to prevent the stiffener132from completely sliding through the base unit opening117and out of the base unit120. Thus, the flange136acts as an anchor in one capacity. The flange136provides a coupling surface between the stiffener132and a de-coupler134, which is further coupled to a stiffener biasing device139(e.g., a spring such as a compression spring). In some embodiments, the stiffener132may include a reduced diameter nose143. The reduced diameter nose143may be able to extend further into a cannula in an eye of a patient.

The stiffener biasing device139applies a biasing force against the de-coupler134and thus the stiffener132in a distal direction (e.g., towards the distal end121) to bias the stiffener132towards a protracted position. Thus, without an application of a force in an opposite, proximal direction (e.g., towards the proximal end125inFIG.1B), the stiffener132is constantly disposed in the protracted position. During use, the probe110may be inserted into an insertion cannula with a hub (e.g., including a valve), at a desired depth. Upon a distal end131of the stiffener132reaching the hub of the insertion cannula, the user may further press the instrument100towards the hub to drive the probe110deeper therein. Application of a force against the hub greater than that of the force provided by the stiffener biasing device139will cause the stiffener132to retract into the base unit120(shown inFIG.4B), allowing a greater portion of the probe110to enter the eye.

In certain embodiments, the stiffener132is sized to possess an axial length sufficient to provide a desired rigidity and stability to the probe110while having a portion thereof still remaining in the interior chamber124when the stiffener132is in the protracted position. For example, the stiffener132may have an axial length between about 0.25 inches and about 1.75 inches, such as between about 0.30 inches and about 1.50 inches. For example, the stiffener132may have an axial length between about 0.50 inches and about 1.25 inches.

In certain embodiments, the stiffener132has a uniform outer diameter from the distal end131to the proximal end133. Having a uniform outer diameter enables a substantial length of the stiffener132to be reciprocated through the base unit opening117without forming an air gap therebetween. However, other shapes and morphologies of the stiffener132are also contemplated. For example, in some embodiments, the stiffener132comprises a square, rectangular, or polygonal tube. In further embodiments, the stiffener132may have a non-uniform outer diameter. For example, the stiffener132may have an outer diameter having one or more dimensions following a step-wise or gradual delta.

In some embodiments, the actuation mechanism may include a biasing device139, a de-coupler134, and an annular flange136integral with or affixed to the stiffener132such that the biasing device is configured to apply a biasing force, through the de-coupler134, against the annular flange136of the stiffener132in the distal direction. In some embodiments, the de-coupler134and the stiffener132are separate components that are biased toward each other by, for example, biasing device139(such as a spring). The de-coupler134may contact annular flange136due to the biasing device139biasing the de-coupler134toward the annular flange136and/or due to external forces on the stiffener132pushing the annular flange136(which may be integral with or attached to the stiffener132) toward the de-coupler134. In some embodiments, the de-coupler134and annular flange136may be otherwise not attached to each other to allow relative movement between the de-coupler134and annular flange136.

FIG.1Billustrates a perspective view of a vitrectomy probe with a dynamically adjustable stiffening sleeve and a control member138. In certain embodiments, the position of the stiffener132is locked in place using the control member138as described below in relation toFIGS.4A-4C. Accordingly, a user may selectively adjust the level of stiffness of the probe110by re-positioning the stiffener132relative to the distal end116, thereby manipulating the amount of support provided to the probe110and stabilizing the instrument100during use thereof.

In some embodiments, the stiffener132includes a keying feature140configured to operatively engage a base unit opening (e.g., a base unit opening117inFIG.4A) in the distal end121of the base unit120to prevent rotation of the stiffener132as further described inFIG.4A. As shown, the keying feature140is a protrusion of the stiffener132with a rectangular-shaped cross-section but may be other shapes in other embodiments, such as a semi-circle or triangle. Note that althoughFIG.1Bshows a keying feature140, in certain embodiments (for example, as seen inFIG.1A), a keying feature140is not used.

FIG.3Aillustrates a perspective view of an illuminator probe1000with a dynamically adjustable stiffening sleeve1032, according to certain embodiments of the present disclosure.FIG.3Billustrates a schematic cross-sectional side view of the illuminator probe1000ofFIG.3A. Illuminator probe1000may comprise a cannula1010surrounding an optical fiber1800that guides light, for example, into the interior of an eye. Dynamically adjustable stiffening sleeve1032may include an annular flange1836that engages a control member biasing device (e.g., spring1849). As stiffening sleeve1032is biased toward a handle portion1850(e.g., as it encounters opposing structure such as a trocar cannula), stiffening sleeve1032may enter nose1810and an interior of the handle portion1850. In some embodiments, the stiffening sleeve1032may include a reduced diameter nose1843. The reduced diameter nose may be able to extend further into a cannula in an eye of a patient. In some embodiments, the dynamically adjustable stiffening sleeve1032may include a biasing device1849, a de-coupler1834, and an annular flange1836integral with or affixed to the stiffener1032such that the biasing device is configured to apply a biasing force, through the de-coupler1834, against the annular flange1836of the stiffener1032in the distal direction. In some embodiments, the de-coupler1834and the stiffener1032are separate components that are biased toward each other by, for example, biasing device1849(such as a spring). The de-coupler1834may contact annular flange1836due to the biasing device1849biasing the de-coupler1834toward the annular flange1836and/or due to external forces on the stiffener1032pushing the annular flange1836(which may be integral with or attached to the stiffener1032) toward the de-coupler1834. In some embodiments, the de-coupler1834and annular flange1836may be otherwise not attached to each other to allow relative movement between the de-coupler1834and annular flange1836.

In some embodiments, spring1849may bias against the de-coupler1834and annular flange1836to restore the stiffening sleeve1032to its extended position as the illuminator probe1000is withdrawn (and the stiffening sleeve is no longer biased against the opposing structure). In some embodiments, the spring may be fixed against plug1830. In some embodiments, spring1849may not be affixed to de-coupler1834or plug1830. In some embodiments, spring1849may be affixed to de-coupler1834and/or plug1830. As further seen inFIG.3B, in some embodiments a coupler1833may couple optical fibers (one optical fiber1800extending outside of the handle1850and one optical fiber extending to the tip. In some embodiments, the optical fiber may be continuous from the exterior of the handle through to the tip (without using a coupler1833).

FIGS.4A and4Billustrate schematic cross-sectional views of the instrument100with the stiffener132positioned at different points along a length L of the probe110. Therefore,FIGS.4A and4Bare herein described together withFIG.1Bfor clarity. When the stiffener132is positioned at different points along the length L, the keying feature140operatively engages the base unit opening117and prevents the stiffener132from rotating. This beneficially ensures the opening of the de-coupler134(referred to as de-coupler opening) does not rotate. A dashed line is shown between a cylindrical body of the stiffener and the keying feature140inFIGS.4A and4B, and later figures including the stiffener132, to emphasize that the keying feature140protrudes from the rest of the stiffener132.

In some embodiments, the stiffener biasing device139applies a biasing force against the de-coupler134and thus the stiffener132in a distal direction (e.g., towards the distal end121) to bias the stiffener132towards a protracted position along the length L of the probe110, as shown inFIG.4A. During use, the probe110may be inserted into an insertion cannula with a hub (e.g., including a valve), at a desired depth along the length L selected by the user. Upon a distal end131of the stiffener132reaching the hub of the insertion cannula, the user may further press the instrument100towards the hub to drive the probe110deeper therein. Application of a force against the hub greater than that of the force provided by the stiffener biasing device139will cause the stiffener132to retract into the base unit120(shown in FIG.4B), allowing a greater portion of the probe110to enter the eye. Once retracted, the stiffener132can be locked in the retracted position by the control member138.

As shown inFIG.4B, the position of the stiffener132can be locked or maintained through the interaction of the control member138and the de-coupler134. For example, a surgeon may press the control member138radially-inward towards the de-coupler134, thereby causing the control member138and the de-coupler134to engage for locking the stiffener132in position. More specifically, the control member138operationally engages the de-coupler134through an opening150in the de-coupler134. The control member138may be a button, knob, switch, toggle, or any other suitable device capable of being actuated by a user. As shown, the de-coupler opening150is a through hole.

As depicted inFIGS.4A and4B, the control member138includes a head142, a protrusion (e.g., a shaft144), and a flange146, wherein the head142and the shaft144are disposed at opposite ends of the control member138and the flange146is in between. The control member138is partially disposed within a cutout128(e.g., a channel or an opening) formed in the base unit120. The cutout128includes multiple-sized passageways141configured to accommodate the features of the control member138. For example, the head142is disposed in a first passageway141A, the flange146is disposed in a second passageway141B, and the shaft144is at least partially disposed in a third passageway141C. The flange146operatively engages the second passageway141B to guide the control member138through the cutout128and ensure the control member138remains coupled to the base unit120. The cutout128runs substantially perpendicular to a longitudinal axis170of the probe110(referred to as a probe longitudinal axis) and enables bidirectional pushing of the control member138along a perpendicular axis172thereof. The perpendicular axis172may be referred to as a longitudinal axis of and with respect to the control member (e.g., a control member longitudinal axis) that is different from the probe longitudinal axis of the probe110.

As shown, a control member biasing device149(e.g., a spring) is disposed in the second passageway141B to bias the control member138in a radially outward direction along the perpendicular axis172. The control member biasing device149applies a control member biasing force against the control member138in a direction substantially parallel to the perpendicular axis172and radially-outward from the de-coupler134to bias the control member138towards a protracted position as shown inFIG.4A. Thus, without an application of a force in an opposite direction to retract the control member138, as shown inFIG.4B, the control member138is constantly disposed in the protracted position. Further, the control member biasing device149, the passageways141, and the head142of the control member138are sized and configured to ensure the shaft144never touches the stiffener biasing device139when the control member138is retracted.

During use, the stiffener132and the de-coupler134are positioned at a retracted point along the length L of the probe110as shown inFIG.4B. The head142of the control member138is depressed by, e.g., a surgeon, and the shaft144operatively engages the de-coupler opening150in the de-coupler134, and thus, the stiffener132. Accordingly, depressing the control member138into the de-coupler opening150holds the stiffener132in a retracted position, beneficially withholding the force from the stiffener biasing device139while the control member138is depressed. Releasing the control member138pushes the control member138towards the protracted position and thus operatively disengages the de-coupler134. The force from the stiffener biasing device139returns the stiffener132to the protracted position as shown inFIG.4A.

Generally, the control member138may be formed of a metallic or composite material. In some embodiments, the control member138is formed of stainless steel, aluminum, or titanium. In other embodiments, the control member138is formed of a polymer composite material or ceramic composite material. The control member138is further discussed inFIG.4C.

The configurations of stiffener132, the de-coupler134, the control member138, and the biasing devices139and149are only exemplary and thus should not be considered limiting. Additional embodiments and configurations for different actuation mechanisms are further described below.

As shown inFIG.4A, a nut180couples the stiffener132to the de-coupler134. In other embodiments, the de-coupler134is a direct extension of the stiffener132. That is, the de-coupler134and the stiffener132are a single, integral component. In other embodiments (e.g., as seen inFIG.2), the de-coupler134and the stiffener132are separate components that are biased toward each other by, for example, biasing device139. In some embodiments, the de-coupler134and the stiffener132are coupled to one another by one or more coupling mechanisms and/or adhesives. In other embodiments, the de-coupler134and the stiffener132may be snap-fit together.

FIG.4Cillustrates a perspective view of the control member138. As shown, the head142of control member138is an ellipse shape and the shaft144and flange146are a circular shape, but each may be a different shape such as an ellipse, circle, triangle, or rectangle. A radially-inward end148of the control member138(e.g., an end closer to the de-coupler134) optionally includes a fillet151or chamfer to facilitate insertion of the shaft144into the de-coupler opening150of the de-coupler134.

FIG.4Dillustrates a perspective view of the de-coupler134. De-coupler134is generally a cylindrical and hollow tube with a cap154and a transition (e.g., a fillet158) between the tube and the cap154. As shown inFIG.4A, the distal end131of the stiffener132can be inserted through an opening156in the cap154and the cap154is configured to couple to the flange136of the stiffener132. Thus, the de-coupler134and the stiffener132move as one piece. The de-coupler opening150in the de-coupler134optionally includes a fillet151or chamfer to facilitate insertion of the shaft144of the control member138.

FIG.4Eillustrates a schematic cross-sectional side view of another exemplary instrument200according to certain embodiments described herein. The instrument200is substantially similar to the instrument100, except for the structure of a multi-opening de-coupler234. The de-coupler234is generally similar to the de-coupler134, except the de-coupler234includes multiple de-coupler openings250. The multiple de-coupler openings250are positioned in a straight line along the length of the de-coupler134, as shown inFIG.4F. The control member138can operationally engage any one of the de-coupler openings250as described in relation toFIG.4Bwith respect to the de-coupler opening150. Thus, the stiffener132position is adjustable relative to the probe110, enabling a user to beneficially lock the position of the stiffener132(e.g., the distal end131of the stiffener132) in place at different points along the length L of the probe110.

In some embodiments, the stiffener132position is adjustable up to a distance of about 15 mm (millimeters) along the length L of the probe110, such as a distance up to about 10 mm along the length L of the probe110. For example, the stiffener132is adjustable up to a distance of about 5 mm along the length L of the probe110.

FIG.4Fillustrates a perspective view of the de-coupler234. As shown, the de-coupler openings250form a straight line along the length of the de-coupler234such that each opening (e.g., a de-coupler opening250A) corresponds to a different stiffener position along the length L of the probe110as discussed in relation toFIG.4E. The de-coupler openings250of the de-coupler234are otherwise similar to the de-coupler opening150of the de-coupler134. As shown, the de-coupler234has four de-coupler openings250, but other embodiments may have more or less de-coupler openings250.

As previously discussed, in the embodiments ofFIGS.1A-4D, depressing the control member138of instrument100locks the de-coupler134and the stiffener132in place and releasing the control member138returns the stiffener132and de-coupler134to a protracted position. In such embodiments, the user, e.g. a surgeon, is required to hold down the control member138in order to lock the stiffener132in place, otherwise the stiffener132is released. However, it may be advantageous to allow the user to lock the stiffener132in place without requiring the user to continuously press or hold the control member138.FIGS.5A-5Hillustrate various examples of de-couplers that can be used in conjunction with various example instruments shown inFIGS.6A-8to allow the user to lock the stiffener in place without having to hold the control member.

FIGS.5A-5Hillustrate perspective views of different de-couplers334. The de-couplers334are generally similar to the de-couplers134and234inFIGS.4D and4F, respectively, except including different types or shapes of de-coupler openings350.

FIG.5Ashows a de-coupler334A including a de-coupler opening350A with a circular cutout360and a groove362A. The circular cutout360is substantially similar to the de-coupler opening150inFIG.4D. The groove362A extends outward from the circular cutout360in a direction that is perpendicular to the probe longitudinal axis170inFIG.4A. The groove362A is used to operatively engage a control member (e.g., a control member438inFIG.6A) and lock the de-coupler334A in place as described in relation toFIGS.6A-6C. This beneficially allows a user to set the position of a stiffener (e.g., a stiffener432inFIG.6B) without continuously depressing the control member.

FIG.5Bshows a de-coupler334B including multiple de-coupler openings350B positioned in a straight line along the length of the de-coupler334B. The de-coupler openings350B are each substantially similar to the de-coupler opening350A ofFIG.5A.

FIG.5Cshows a de-coupler334C including a channel-shaped de-coupler opening350C that is positioned along a straight line along the length of the de-coupler334C. The de-coupler opening350C includes a de-coupler channel364extending along the length of the de-coupler334C and several grooves362A. The grooves362A extend outward from the de-coupler channel364in a perpendicular direction (similar to that ofFIG.5A) and are positioned at several locations along the length of the de-coupler334C.

The de-coupler opening350C is such that a control member can be depressed and a shaft of the control member (e.g., a shaft444and a control member438inFIG.6A) can be inserted anywhere along the de-coupler channel364. The de-coupler opening250C beneficially allows a user to be less precise when operationally engaging the de-coupler334C with the control member. The grooves362A are used to operatively engage the control member at different positions along the de-coupler channel364and lock the de-coupler334C in place as described in relation toFIG.5A.

FIG.5Dshows a de-coupler334D including a de-coupler opening350D. The de-coupler opening350D is generally similar to the de-coupler opening350C ofFIG.5C, except the de-coupler channel364includes a channel entryway365at a proximal end (e.g., towards the proximal end125inFIG.1B). The channel entryway365is a breach in the de-coupler334D.

Note that although the de-coupler openings350C and350D can be used in conjunction with a control member that is configured to be depressed with the use of a biasing device (e.g., control member138,438, etc.), de-coupler openings350C and350D also allow for embodiments in which a control member (e.g., control member638ofFIG.8) is positioned in a depressed state at all times, such that the tip of the shaft or a notch of the shaft (e.g., notch645described below) is aligned (e.g., depth-wise) with and/or surrounded by the inner walls of the de-coupler opening350D or350C at all times. For example, in the case of de-coupler opening350C, the tip of the shaft (or the notch) can be disposed in the de-coupler opening350C at all times, including when the stiffener is in a protracted position as well as when the stiffener is in a retracted position. In the example of de-coupler opening350D, even if the control member is not positioned over the de-coupler334D when the stiffener is in a protracted position (e.g., because the de-coupler334D may not be long enough), the shaft can slide through the channel entry way365as the de-coupler334D is retracted.

FIG.5E-5Hshow de-couplers334E-H, respectively. The de-coupler openings350E-H ofFIGS.5E-5Hare generally similar to the de-coupler openings350A-D ofFIGS.5A-5D, respectively, except for the grooves. The grooves362B of de-couplers334E-H differ from the grooves362A inFIGS.5A-5Din that the each of the grooves362B includes a leg366and is generally a dogleg or L-shaped pattern. When de-couplers334E-H are positioned in an instrument (e.g., an instrument400inFIGS.6B and6C), the leg366of the dogleg is parallel to the probe longitudinal axis170and extends towards a proximal end of the base unit120(e.g., towards the proximal end125inFIG.1B). The leg366is used to operatively engage a control member (e.g., a control member438inFIG.6A) when the control member is in one of the grooves362B and lock the de-couplers334E-H in place. The leg366ensures the de-couplers334E-H do not rotate when locked in place as described in relation toFIGS.6B and6C.

The de-couplers334A-H described in relation toFIGS.5A-5Hcan be used in several different instruments.FIGS.6A-6Cshow how a stiffener432can be rotated to engage a control member438using the grooves362A and362B shown inFIGS.5A-5H.FIGS.7A-8show how the control member438can slide to engage the grooves362A and362B.

FIGS.6A-6Cillustrate different features and views of another exemplary instrument400, which is generally similar to exemplary instrument100inFIGS.1-4B. The instrument400includes a control member438, a stiffener432, and the de-coupler334A fromFIG.5A. The control member438is generally similar to the control member138, except for having a notch, and is described in relation toFIG.6A. The stiffener432is substantially similar to the stiffener132, except the stiffener432does not include the keying feature140. Thus, the stiffener432and the de-coupler334A are free to collectively rotate about the probe longitudinal axis (e.g., the probe longitudinal axis170shown inFIG.4A) of the probe110.

FIG.6Aillustrates a perspective view of the control member438. As shown, the control member438includes a head142, a flange146, and a shaft444. The shaft444is substantially similar to the shaft144inFIG.4C, except the shaft444includes a notch445near the radially-inward end148of the control member438. The notch445operatively engages the groove362A in the de-coupler334A, as described in relation toFIGS.6B and6C.

FIGS.6B and6Cillustrate schematic cross-sectional views of the exemplary instrument400from a viewpoint at a distal end of the instrument400. The stiffener biasing device139is omitted to better illustrate the locking mechanism of the control member438and the de-coupler334A. As previously discussed, the stiffener432and the de-coupler334A are free to rotate together about the probe longitudinal axis170. As shown inFIG.6B, the control member438is depressed and the shaft444of the control member438is inserted into the circular cutout360of the de-coupler opening350A such that the notch445aligns with the groove362A in the de-coupler334A. As shown inFIG.6C, the stiffener432and thus the de-coupler334A rotate clockwise476and the notch445operatively engages the groove362A. The stiffener432can be rotated relative to the probe110or the base unit120of the instrument100manually by a surgeon. For example, the notch445fits inside the groove362A and overhangs the de-coupler334A, guiding the notch445into the groove362A as the stiffener432and de-coupler334A are rotated. The control member438is then released and the control member biasing device149pushes the control member438in a radially-outward direction from the de-coupler334A such that the notch445pushes against the de-coupler334A and the control member438locks the de-coupler334A and, thereby, the stiffener432in place. To release the de-coupler334A, the surgeon can rotate the stiffener432counter-clockwise, thereby moving the notch445out of the groove362A. The control member438is released and the stiffener biasing device139pushes the stiffener to the protracted position as shown inFIG.4A.

In other embodiments not shown, the de-coupler (e.g., the de-coupler334E inFIG.5E) has a groove362B with a leg366. Once the notch445operationally engages the groove362B and the de-coupler334E is rotated as far clockwise476as possible, the stiffener biasing device139pushes the de-coupler in the distal direction (e.g., towards the distal end121inFIG.1B) and the notch445operationally engages the leg366of the groove362B, beneficially preventing rotation and also locking the de-coupler334E and the stiffener432in place. To release the de-coupler334E, the stiffener432is pushed in a proximal direction (e.g., towards the proximal end125inFIG.1B) against the force of the stiffener biasing device139and rotated counter-clockwise. This moves the notch445out of the leg366and the groove362B. The control member438is released and the stiffener biasing device139pushes the stiffener to the protracted position as shown inFIG.4A.

FIG.7Aillustrates a perspective view of an exemplary instrument500according to certain embodiments described herein. The instrument500is generally similar to instruments100and400inFIGS.1B and6B-C, respectively, except as discussed herein. In particular, the instrument500uses the control member438to push radially-inward towards a de-coupler (e.g., the de-coupler334A inFIG.7B) and slide to lock the de-coupler and the stiffener132in position. The instrument500includes a base unit520that has a cutout528and an outer surface522. The cutout may be referred to as a base unit channel that is different from the de-coupler channel of the de-coupler. The control member438is partially disposed inside the cutout528. The base unit520and the outer surface522are substantially similar to the base unit120and the outer surface522inFIG.1B, except for the differences from the cutout528. The base unit520includes a distal end521and a proximal end525.

FIGS.7B and7Cillustrate schematic cross-sectional views of the instrument500. Instrument500uses the stiffener132that was described in relation toFIGS.1A-4B. As previously discussed inFIGS.4A and4B, the stiffener132is constrained from rotation about the probe longitudinal axis170by the keying feature140. Thus, the de-coupler334A is constrained from rotating. The stiffener biasing device139is omitted to better illustrate the locking mechanism of the control member438and the de-coupler334A.

The cutout528is configured to allow bidirectional pushing of the control member438along the perpendicular axis172, similar to what was previously described in relation toFIGS.4A and4B. The cutout528is further configured to allow sliding of the control member438about the probe longitudinal axis170. As shown inFIG.7B, the control member438is depressed along the perpendicular axis172and the shaft444of the control member438is inserted into the circular cutout360of the de-coupler334A such that the notch445aligns with the groove362A in the de-coupler334A. As shown inFIG.7C, the control member438and the notch445slide about the probe longitudinal axis170and the notch445operatively engages the groove362A. The control member438locks the de-coupler334A and the stiffener432in place similar to what was described in relation toFIGS.6B and6C. To release the de-coupler334A, the control member438slides in an opposite direction to move the notch445out of the groove362A. The control member438is released and the stiffener biasing device139pushes the stiffener132to the protracted position as shown inFIG.4A.

As described above, although previousFIGS.1A-4F and6A-7Cdiscussed depressing a control member to insert the shaft into an opening of a de-coupler, in certain other embodiments (shown inFIG.8) the control member's shaft may slide through or be positioned within a channel-shaped de-coupler opening of the de-couplers shown inFIG.5C,5D,5G, or5H without the control member having to be depressed. In such embodiments, to lock the stiffener in place, the user can slide control member, for example, about the probe longitudinal axis170, as further described in relation toFIG.8.

FIG.8illustrates a schematic cross-sectional view of an exemplary instrument600. The cross-sectional view is substantially similar to the cross-sectional view ofFIGS.7B and7C. The instrument600is generally similar to the instrument500inFIGS.7B and7C, except as discussed herein. In particular, the instrument600uses the control member638to slide to lock the stiffener132in position. The control member638includes a head642, a flange646, and a shaft644. The shaft644includes a notch645. The stiffener biasing device139is omitted to better illustrate the locking mechanism of the control member638and the de-coupler334D (or de-coupler334H)

The instrument600includes a base unit620having a cutout628. The cutout628may be referred to as a base unit channel that is different from the de-coupler channel of the de-coupler. The cutout628includes multiple-sized passageways641similar to the passageways141discussed inFIGS.4A and4B, except a second passageway641B conforms to the flange646of the control member638. The flange646operatively engages the second passageway641B, which guides the flange646and thus the control member638through the cutout628about the probe longitudinal axis170when the control member638is slidably actuated by the user. Thus, the second passageway641B is configured to be a guide channel to guide the control member638when actuated by the user and may be referred to as a guide channel. As shown, the second passageway641B is a curved channel that is curved about the probe longitudinal axis170.

The de-coupler334D, as previously discussed inFIG.5D, includes the de-coupler channel364and the channel entryway365. The stiffener132travels along the length L of the probe110. As the stiffener132travels towards the proximal end525of the base unit620, the channel entryway365and the de-coupler channel364of the de-coupler334D operatively engage the notch645of the control member638. As shown, when the shaft644and the notch645align with one of grooves362A, the control member638can be slid about the probe longitudinal axis170and into one of the grooves362A, causing the notch645to operatively engage the groove. Therefore, the control member638locks the de-coupler334D and the stiffener132in place similar to as described in relation toFIGS.7B and7C. To release the de-coupler334D, the control member638slides in an opposite direction to move the notch645out of the groove362A and the stiffener biasing device139pushes the stiffener132to the protracted position as shown inFIG.4A.

In certain embodiments, the sliding-only locking mechanism of the instrument600is compatible with de-couplers334C and334G ofFIGS.5C and5G, respectively. For example, in relation to the de-coupler334C, the shaft444of the control member438is disposed in the de-coupler channel364at all times while the stiffener132travels along the length L of the probe110. When locking the de-coupler334C in place, the notch445of the control member438operationally engages one of the grooves362A of the de-coupler334C as previously described with respect to the de-coupler334D. The de-coupler334G may be used in a similar manner. In such embodiments, a stiffener without a keying feature (e.g., the stiffener432) may be used because the control member is always disposed inside an opening of the de-coupler.

In another embodiment, the cutout628comprises a track with substantially planar surfaces, perpendicular to the probe longitudinal axis170and the perpendicular axis172, upon which a control member may slidably and dynamically be actuated by the user. The planar surfaces of the track provide a flat surface for a control member (e.g., the control member638) to traverse. In such embodiments, the second passageway641B is a linear channel that is straight along the track.

FIG.9Aillustrates a perspective view of an exemplary instrument700according to certain embodiments described herein. Although instrument700is generally similar to the instrument100fromFIG.4A, the configuration of instrument700may be applied to any of the instruments discussed herein.

As shown, the instrument700comprises a probe710and a base unit720having a distal end721. The base unit720includes an interior chamber724and a base unit opening717. A stiffener732surrounds the probe710. The stiffener732and the probe710are disposed in the interior chamber724and through the base unit opening717of a distal end721of the base unit720. The stiffener732includes a keying feature740which operationally engages the base unit opening717to prevent the stiffener732from rotating.

A cutout728is formed in the base unit720and a control member738is partially disposed in a cutout728. The control member738includes a control member biasing device749. The control member biasing device749includes several extensions as described in relation toFIG.9B. The cutout728includes multiple-sized passageways741configured to accommodate the control member738and the control member biasing device749. For example, a passageway741B is formed to accommodate a deflection of the control member biasing device749when the control member738is depressed radially-inward towards the de-coupler734. The passageways741A and741C are similarly formed to accommodate other parts of the control member738.

A de-coupler734is coupled to the stiffener732and a biasing device739applies a biasing force against the de-coupler134. The biasing force pushes the de-coupler734and the stiffener732in a distal direction (e.g., towards the distal end721) to a protracted position as shown inFIG.9A. When the stiffener732and the de-coupler734are retracted in a direction opposite the distal direction (e.g., a proximal direction), the control member738may be depressed to engage the de-coupler734and lock the stiffener732in position as similarly described inFIGS.4A and4B.

FIG.9Billustrates a perspective view of the control member738. As shown, the control member738includes a head742and a shaft744disposed at opposite ends of the control member738. A flange746is disposed between the head742and the shaft744. The flange746includes several extensions747that comprise the control member biasing device749. The extensions747extend in a direction towards and radially outward from the shaft744. Thus, as shown, the control member biasing device749and the control member738are a single, integral component, beneficially reducing the total components in instrument700. In certain embodiments, the extensions747are made from a flexible but stiff material such as polypropylene, polycarbonate, acrylonitrile butadiene styrene, and the like. When the control member738is depressed, the extensions747contact the passageway741B and the force depressing the control member738deforms the extensions747as the shaft744travels towards the de-coupler734. When the force is removed, the extensions747return to their un-deformed shape. Thus, the extensions747function as a spring.

In summary, embodiments of the present disclosure include structures and mechanisms for adjusting the stiffness of microsurgical instruments, such as small-gauge instruments for minimally-invasive ophthalmologic operations. The instruments described above include embodiments wherein a user, such as a surgeon, may adjust the stiffness of the instruments during use thereof. Accordingly, the described embodiments enable a surgeon to access a wider range of tissues with a single instrument, thus expanding the applicability of smaller gauge instruments to a greater range of indications.

Certain embodiments described herein enable a surgeon to dynamically adjust the stiffness and length of a vitrectomy probe to access all areas of a vitreous cavity during a single procedure. The adjustment of the probe may be carried out prior to insertion of the probe into the eye or after the probe has already been inserted therein. Thus, the described embodiments may be utilized to facilitate access to the posterior segment of an eye during vitreous surgeries while retaining the benefits of smaller gauge probes, such as increased patient comfort, less conjunctival scarring, less postoperative inflammation, and faster healing time. Although vitreous surgery is discussed as an example of a surgical procedure that may benefit from the described embodiments, the advantages of an instrument with adjustable stiffness may benefit other surgical procedures as well.

Additional Considerations