Patent Description:
During certain surgical procedures (e.g., ophthalmic procedures) a surgeon is required to manipulate (e.g., remove, cut, peel, etc.) certain tissues within a body part by using forceps, scissors, etc. Examples of such surgical procedures are internal limiting membrane (ILM) removal and epiretinal membrane (ERM) removal for treating different macular surface diseases. During such procedures, a surgeon inserts the tip of a surgical instrument, which, for example, functions as forceps, into a patient's eye globe and uses the forceps to grasp and peel the ILM/ERM. Certain designs are currently used for providing a surgical instrument with an actuation mechanism that allows a surgeon to close and open the jaws of the forceps or scissors, which are located at the tip of a surgical instrument. However, in certain cases, the existing actuation mechanisms involve too many parts, are structurally complicated, and/or are difficult to assemble.

The cited prior art document <CIT> relates to a plurality of opposing flexible bows which are portions of a unitary injection bow member. <CIT> Al relates to an instrument dispenser having an actuation handle which can be squeezed. <CIT> is directed to a light transmitting medical instrument which comprises a light pipe having a first end operatively coupled to a light source and a second end having a functional tip having at least two arms.

The present disclosure relates generally to a surgical instrument having an actuation mechanism including resilient, arcuate levers. There is provided a surgical instrument according to independent claim <NUM>, further optional features are provided in the dependent claims.

Particular embodiments disclosed herein provide a surgical instrument comprising a device comprising having a functional end configured to be inserted into a body part. In particular embodiments, the functional end may comprise forceps or scissors. In particular embodiments, the surgical instrument further comprises a shaft coupled to a proximal end of the device, and a shaft housing configured to receive a distal end of the shaft and operable to move along a central axis of the shaft. The surgical instrument further comprises a tube coupled to the distal end of the shaft housing and configured to partially house the device such that the functional end of the device at least partially extends beyond the distal end of the tube. The surgical instrument further comprises a plurality of arcuate levers, each arcuate lever having a proximal end coupled to the shaft and a distal end coupled to the shaft housing. Pressing one or more of the plurality of arcuate levers moves the shaft housing and tube toward the functional end the device, causing the tube to transition the device from a deactivated state to an activated state, such as closing the jaws of a pair of forceps if the functional end of device comprises forceps.

Particular embodiments of the present disclosure provide a surgical instrument having an actuation mechanism including resilient, arcuate levers.

<FIG> illustrates an example of a surgical instrument with a prior art actuation mechanism. As shown, surgical instrument <NUM> comprises a handle <NUM>, a plurality of actuation levers <NUM>, a housing <NUM>, an actuation tube <NUM>, and a device, shown as forceps <NUM>, at the tip of the probe. Each actuation lever <NUM> is a single piece comprising a first leg <NUM> and a second leg <NUM> joined at flexible juncture <NUM>. In other embodiments, the first leg <NUM> and second leg <NUM> may be separate pieces coupled together with a hinge. Each actuation lever <NUM> may be made from shape memory material, such as titanium, stainless steel or suitable thermoplastic. Actuation tube <NUM> may be any suitable medical grade tubing, such as titanium, stainless steel, or suitable polymer and is sized so that forceps <NUM> reciprocate easily within. Forceps <NUM> are generally made from stainless steel or titanium, but other materials may also be used.

Surgical instrument <NUM> is designed so that in use, when the plurality of actuation levers <NUM> is in its relaxed state, forceps <NUM> protrude or extend beyond the distal end of actuation tube <NUM>, which is coupled to a housing <NUM>. Squeezing one or more of the actuation levers <NUM> causes the respective actuation lever <NUM> to flex at juncture <NUM>, pushing housing <NUM> forward relative to handle <NUM>. The forward movement of housing <NUM> is transferred to actuation tube <NUM>, causing actuation tube <NUM> to slide forward over a distal portion of the jaws of forceps <NUM>, thereby activating forceps <NUM> by compressing together the jaws. By closing jaws of forceps <NUM>, the surgeon is able to, for example, grasp and peel a tissue (e.g., ILM) within a body part.

In the example of <FIG>, actuation levers <NUM> may be structurally complicated and/or difficult to assemble. Accordingly, certain embodiments described herein relate to an actuation handle with an actuation mechanism including arcuate levers. In particular embodiments, this may reduce the structural complexity of the actuation mechanism and allow for easier assembly.

<FIG> illustrates an outside view of an example surgical instrument <NUM> in accordance with the teachings of the present disclosure. As shown in <FIG>, surgical instrument <NUM> comprises a rear cap <NUM>, a shaft <NUM>, a shaft housing <NUM>, an actuation tube <NUM>, a stop ring <NUM>, a plurality of levers <NUM> (e.g., 210a, 210b, 210c, etc.), and a device <NUM>.

Device <NUM> may be any surgical device that is shaped to fit in tube <NUM> with a distal end that is referred to as a functional end (e.g., a movable or active end). For example, device <NUM> may be shaped as a needle with a functional end, which may comprise forceps, scissors, etc., with jaws or arms. The proximal end (not shown) of device <NUM> is coupled to shaft <NUM>, as shown in <FIG> and <FIG>.

Levers <NUM> are coupled to shaft housing <NUM> at their distal ends and to shaft <NUM> at their proximal ends. Each lever <NUM> has a generally arcuate shape such that the middle of each lever <NUM> is further away from shaft <NUM> and shaft housing <NUM> than the distal and proximal ends of the respective lever. Levers <NUM> are formed of resilient material (e.g., flexible and/or springy material) such that, when pressed inward toward shaft <NUM>, levers <NUM> flex, but revert back to their at-rest positions when they are released. In certain embodiments, levers <NUM> are formed of polycarbonate, polyetheretherketone (PEEK), or similar thermoplastic material. Unlike the prior art levers <NUM> shown in <FIG>, levers <NUM> are not configured to flex at a discontinuity (e.g., junction <NUM> in <FIG>). Instead, levers <NUM> are configured to flex similar to leaf springs. When a lever <NUM> is pressed inward towards shaft <NUM>, the compression of the lever causes the lever <NUM> to transition from a first, steeper curvature to a second, shallower curvature, in the process moving the distal end of the lever <NUM> towards the distal end of instrument <NUM>. Surgical instrument <NUM> is designed so that in use, when levers <NUM> are in their relaxed or at-rest state, the functional end of device <NUM> protrudes or extends beyond the distal end of tube <NUM>. Note that <FIG> illustrates levers <NUM> in their at-rest or deactivated position while <FIG> illustrates levers <NUM> in their pressed or activated position.

When levers <NUM> are pressed, they push shaft housing <NUM> forward relative to shaft <NUM> and device <NUM>. The forward movement of shaft housing <NUM> is transferred to tube <NUM>, causing tube <NUM> to slide forward and activate device <NUM>. Device <NUM> is activated as a result of the forward movement of tube <NUM>, which presses the jaws or arms of device <NUM> together. An activated device refers to a device whose jaws or arms are closed. As shown, a stop ring <NUM> may be coupled to or placed around shaft housing <NUM> to limit the movement of levers <NUM> towards shaft housing <NUM>. In other words, stop ring <NUM> prevents levers <NUM> from over extending (e.g., becoming completely flat) when, for example, a user applies too much pressure on them.

Levers <NUM>, shaft housing <NUM>, stop ring <NUM>, shaft <NUM>, and tube <NUM> may be collectively referred to as an actuation handle that is configured to activate and deactivate device <NUM> of surgical instrument <NUM>. In the example of <FIG>, surgical instrument <NUM> comprises seven levers <NUM>. However, a fewer or larger number of levers <NUM> may be used in other embodiments.

<FIG> illustrates an exploded view of surgical instrument <NUM> of <FIG>. As shown in <FIG>, a proximal end <NUM> of shaft <NUM> is coupled to (e.g., press-fitted or inserted into) rear cap <NUM> while a distal end <NUM> of shaft <NUM> is inserted into the shaft housing <NUM>. Shaft <NUM> also comprises a central element <NUM> that a distal end <NUM> of shaft housing <NUM> may, in certain embodiments, make contact with when levers <NUM> are relaxed (e.g., when device <NUM> is in the deactivated state). In such embodiments, when levers <NUM> are pressed, shaft housing <NUM> slides forward relative to shaft <NUM> such that distal end <NUM> of shaft <NUM> and central element <NUM> no longer touch. In other embodiments, distal end <NUM> of shaft housing <NUM> and central element <NUM> never touch even when levers <NUM> are relaxed.

As shown in <FIG>, each lever <NUM> includes a lever tail <NUM> at its proximal end and a lever head <NUM> at its distal end. Each lever tail <NUM> is configured to couple the respective lever <NUM> to central element <NUM>, and each lever head <NUM> is configured to couple the respective lever <NUM> to shaft housing <NUM>. In particular embodiments, this coupling may be accomplished by having each lever tail and/or lever head mate with a corresponding housing on the central element <NUM> or shaft housing <NUM>. For example, as illustrated in <FIG>, central element <NUM> comprises a plurality of tail housings <NUM>, each configured to house a lever tail <NUM> of a lever <NUM>. In particular embodiments, each lever tail <NUM> may have a cylindrical shape and the corresponding tail housing <NUM> may comprise a u-shaped groove that is configured to house the cylindrical lever tail <NUM>. In such an embodiment, a tail housing <NUM> and a lever tail <NUM> are coupled such that the lever tail <NUM> is able to rotate within and relative to the tail housing <NUM> when levers <NUM> are being pressed and released.

Similarly, as shown in <FIG>, shaft housing <NUM> comprises a plurality of head housings <NUM>, each configured to house a lever head <NUM> of a lever <NUM>. More specifically, each head housing <NUM> comprises a u-shaped groove that is configured to house a lever head <NUM> that, similar to a lever tail <NUM>, is also shaped somewhat similar to a cylinder. Further, a head housing <NUM> and a lever head <NUM> are coupled such that the lever head <NUM> is able to rotate within and relative to the head housing <NUM> when levers <NUM> are being pressed and released. Note that the cylindrical shapes of lever tail <NUM> and lever head <NUM> as well as the shapes of tail housing <NUM> and head housing <NUM> are merely exemplary. In other examples, any lever tail <NUM> and tail housing <NUM> as well as lever head <NUM> and head housing <NUM> may be of any suitable complementary shapes. Also, in certain embodiments, levers <NUM> may be coupled to shaft <NUM> and shaft housing <NUM> using other mechanisms. For example, lever tails <NUM> and shaft <NUM> may be coupled together using film hinges. In another example, film hinges may instead be used to couple lever heads <NUM> and shaft housing <NUM>.

In particular embodiments, shaft <NUM> further comprises a tube- or tunnel-shaped passage <NUM> into which the proximal end of device <NUM> is configured to be partially inserted. As described above, device <NUM> is attached or coupled to shaft <NUM> such as to prevent device <NUM> from moving, longitudinally or otherwise, relative to shaft <NUM>. As such, the proximal end of device <NUM> may be glued to the end of passage <NUM>.

In the invention, shaft <NUM> comprises one or more protrusions <NUM> used for ensuring that shaft <NUM> does not rotate within and relative to shaft housing <NUM> when levers <NUM> are pressed. In the example shown in <FIG> shaft <NUM> has four such protrusions <NUM> (three of which are visible in the figure) extending radially from the shaft at uniform intervals. Because of protrusions <NUM>, when viewed down its central axis, shaft <NUM> may have a cross-shaped cross-section. As shown in <FIG>, shaft <NUM> comprises similar protrusions at its proximal end. In the invention, protrusions <NUM> correspond to a plurality of receptacles (not illustrated) on the interior of shaft housing <NUM> into which protrusions <NUM> may be inserted. The interaction of protrusions <NUM> and these receptacles helps limit or prevent shaft <NUM> from rotating in relation to shaft housing <NUM> when levers <NUM> are pressed. Although shaft <NUM> has been described above as having four protrusions <NUM>, in other embodiments shaft <NUM> may comprise other numbers and arrangements of protrusions.

<FIG> illustrates a cross-sectional view of surgical instrument <NUM> when levers <NUM> are in a relaxed or at-rest position, in accordance with a particular embodiment. As shown, proximal end <NUM> of shaft <NUM> is inserted into rear cap <NUM> while distal end <NUM> of shaft <NUM> is inserted into shaft housing <NUM>. The proximal end of device <NUM> is coupled to a device housing <NUM> of shaft <NUM>. Device housing <NUM> is a cylindrical element into which the proximal end of device <NUM> is partially inserted. In other examples, device housing <NUM> may be of any other suitable shape. As described above, the proximal end of device <NUM> and device housing <NUM> may be coupled together using adhesive material. In other embodiments, one of a plurality of other techniques may be used for coupling the proximal end of device <NUM> and device housing <NUM>.

As shown, device <NUM> extends through passage <NUM> of shaft <NUM> as well as tube <NUM>. When levers are relaxed, as is the case in the example of <FIG>, the distal or functional end of device <NUM> extends beyond the distal end of tube <NUM>. As a result, in the example of <FIG>, device <NUM> is in a deactivated state. In the invention, the arcuate length of levers <NUM> directly correspond to how far shaft housing <NUM> slides forward when levers <NUM> are pressed. The larger the arcuate length of levers <NUM> (e.g., the steeper the curve of levers <NUM>), the further shaft housing <NUM> slides forward when levers <NUM> are pressed inward.

<FIG> illustrates a cross-sectional view of surgical instrument <NUM> when device <NUM> is in the activated state, in accordance with a particular embodiment. As shown, levers <NUM> flex when they are pressed inward toward shaft <NUM>, transitioning from a first, steeper curvature to a second, shallower curvature and, as a result, move or push shaft housing <NUM> forward relative to shaft <NUM> and device <NUM>. The forward movement of shaft housing <NUM> is transferred to tube <NUM>, causing tube <NUM> to slide forward and activate device <NUM>. As shown, relative to <FIG>, shaft housing <NUM> has moved forward such that distal end <NUM> of shaft housing <NUM> is separated from central element <NUM> of shaft <NUM> by a larger distance. Further, the functional end of device <NUM> is activated because the jaws or arms are closed by the distal end of tube <NUM>. When levers <NUM> are released, they transition back to their original curvature, pulling shaft housing <NUM> backward, causing tube <NUM> to deactivate the functional end of device <NUM> by opening the jaws or arms. As described above, because levers <NUM> are resilient, pressing them results a certain amount of spring force that causes levers <NUM> to revert back to their at-rest state when they are released.

Claim 1:
A surgical instrument (<NUM>, <NUM>), comprising:
a device (<NUM>) having a functional end configured to be inserted into a body part;
a shaft (<NUM>) coupled to a proximal end of the device;
a shaft housing (<NUM>) having a proximal end configured to receive a distal end (<NUM>) of the shaft (<NUM>) and operable to move along a central axis of the shaft;
a tube (<NUM>) coupled to the distal end of the shaft housing (<NUM>) and configured to partially house the device (<NUM>) such that the functional end of the device at least partially extends beyond the distal end of the tube (<NUM>);
a plurality of arcuate levers (<NUM>, 210a, 210b, 210c), each arcuate lever having a proximal end coupled to the shaft and a distal end coupled to the shaft housing such that pressing one or more of the plurality of arcuate levers moves the shaft housing and the tube toward the functional end of the device, causing the tube to transition the device from a deactivated state to an activated state;
the proximal end of each of the plurality of arcuate levers comprises a lever tail (<NUM>) configured to rotate within a tail housing (<NUM>) of the shaft (<NUM>); and
the distal end of each of the plurality of arcuate levers comprises a lever head (<NUM>) configured to rotate within a head housing (<NUM>) of the shaft housing (<NUM>);
wherein pressing the one or more of the plurality of arcuate levers causes the lever tail and the lever head of each of the plurality of arcuate levers to rotate within the respective tail housing and head housing, and
characterised in that
the shaft (<NUM>) comprises a plurality of protrusions (<NUM>) extending outward from the central axis of the shaft; and
the shaft housing (<NUM>) comprises a plurality of receptacles on an interior thereof, each receptacle configured to receive one of the plurality of protrusions when the shaft is received by the shaft housing, such that, when the one or more of the plurality of arcuate levers (<NUM>, 210a, 210b, 210c) are pressed, interaction of the respective plurality of protrusions and plurality of receptacles allows the shaft housing to move along the central axis of the shaft toward the functional end of the device in correspondence to a length of the one or more of the plurality of arcuate levers while limiting rotation of the shaft relative to the shaft housing.