Disposable device for cutting arthroscopic sutures

Abstract

A suture cutter that allows for easy loading and holding of a suture, tensioned or untensioned, for cutting. The cutter features a handle with an integrated lever and a shaft attached to the handle that extends from it. The tip has a cutting channel with a cradle to hold the suture before cutting. A piston in the handle actuates a blade pusher to cut the suture in response to the lever's movement. A guide assembly in the body consists of two elements folded by a flexible hinge that provides a groove for the piston head. The pusher is flat and oriented horizontally within the shaft, while the blade is flat and oriented vertically at a right angle to the pusher. The blade has a tab that engages in a notch in the pusher to secure the blade and pusher.

Description

Disposable device for cutting arthroscopic sutures Background of the invention 1. Field of the invention The present invention relates to a disposable surgical suture cutting device and, more particularly, to a cutting device having improved suture containment. 2. Description of the related technique Surgical sutures are used in almost every surgical procedure. Although the medical industry often uses the generic term "suture" to describe any filament used in these surgical procedures, the suture material can vary depending on the task at hand. A suture material can be used that rivals stainless steel wire in terms of strength while retaining the flexibility of lower-strength materials. For example, ultra-high-molecular-weight polyethylene is currently used as a non-absorbable suture in areas such as knee, shoulder, and other connective tissue repairs, where the surrounding tissue and / or suture anchors can withstand the additional loads that such a high-strength suture material allows. As a result, suture materials can become very difficult to cut as their strength increases.A conventional approach to handling high-strength suture material involves using a suture cutter designed to cut various suture materials. However, these devices are not always suitable for capturing and retaining the suture being cut, especially if the suture is not under tension or if the suture tension changes after capture. Consequently, there is a need in the technique for a suture cutter with improved suture loading and capture capabilities. US 2011 / 313430 A1 Discloses a suture cutter with the features of the preamble of this claim 1. Another conventional suture cutter is described in US 2014 / 005689 A1. Brief summary of the invention The present invention is a suture cutter that can easily load and hold a tensioned or untensioned suture in place for cutting. The invention is defined in independent claim 1. Certain optional features of the invention are defined in dependent claims. The suture cutter has a handle with a body and a lever integrally formed with the body such that the lever is skewed to return to an initial position if the lever is moved from the initial position to a user-operated position. A shaft is attached to and extends longitudinally from the handle. A tip has a channel extending transversely through the tip, allowing access to a cradle, and a blade that is movable within the tip between a retracted position and an extended position in which the blade passes through the cradle.A piston is located within the handle and moves longitudinally within the handle in response to lever movement. A pusher is interconnected to the blade and piston so that lever movement from the initial to the actuated position causes the blade to move from the retracted to the extended position. The body includes a guide assembly with a pair of opposing members, each having a corresponding pair of opposing grooves that align to form a guide for a piston head. The pair of opposing members of the guide assembly are coupled together by a pair of live hinges. The piston includes a post extending from the piston head to engage the lever. A pivot block is located in the body in contact with the piston, so that lever movement against the piston post causes the piston head to move longitudinally within the guide assembly.The pusher is flat and oriented horizontally within the shaft. The blade is flat and oriented vertically within the shaft to form a right angle with the pusher. The blade has a tongue that is captured by a notch in the pusher to interlock the blade and pusher. The shaft includes a plurality of grooves that are captured by a corresponding plurality of retainers in the guide assembly. In one embodiment, the tip channel narrows inward from a wider first diameter to a narrower second diameter near the cradle. In another embodiment, the tip channel may be contoured to discourage suturing if the channel exists. In yet another embodiment, the tip may include a cover that can slide longitudinally between a first position that closes communication with the channel and a second position that opens communication with the channel. Brief description of the various views of the drawings The present invention will be more fully understood and appreciated by reading the following Detailed Description together with the accompanying drawings, in which: FIG.1 is a perspective view of a suture cutter according to the present invention in a fully assembled state; FIG. 2 is a view of a suture cutter according to the present invention in a partially assembled state with a piston guide deployed; FIG.3 is a view of a suture cutter handle in a partially assembled state with the piston guide deployed, the piston displaced, and the lever in a non-tilted position; FIG.4 is a view of a suture in the partial and full assembly states showing the piston guide folding into place to complete the assembly of the body, piston, and lever; FIG. 5 is a perspective view of the shaft of a suture cutter according to the present invention; FIG. 6 shows a side view of the shaft of a suture cutter according to the present invention; FIG. 7 is a side and close-up view of a cutting tip for a suture cutter according to the present invention; FIG.8 is a side view of a suture cutter blade next to a bottom view of a tip showing the interlocking structure of the blade and tip; FIG.9 shows a side view of a blade pusher for a suture cutter according to the present invention; FIG. 10 is a cross-section showing the orientation of the pusher and blade in a suture cutter according to the present invention; FIG. 11 is a pair of opposing side views of a tip having suture capture channel surfaces according to the present invention; and FIG.12 is a side view of another embodiment of a cutting tip for a suture cutter according to the present invention. Detailed description of the invention In the figures, where identical numbers refer to equivalent parts throughout the document, FIG. 1 shows a suture cutter 10 having a handle 12, a cannulated shaft 14 extending from the handle 12, and a tip 16 attached to the end of the cannulated shaft 14. Referring to FIG. 2, a blade 18 is arranged at the tip 16 and driven by a pusher 20 that extends within the cannulated shaft 14 between the blade 18 and the handle 12. The pusher 20 is preferably formed from flat material and is oriented horizontally within the shaft 14. Referring to FIG. 3, the handle 12 includes a flexible lever 24 integrally formed with the handle body 26 to provide a flexible mechanism that can store energy when a user squeezes it, so that the lever 24 returns to its original position when a user releases it. FIG. Figure 3 shows the handle in a pre-assembled configuration. When fully assembled, lever 24 is positioned to engage a piston 30 which can actuate the flat material pusher 20 to actuate the blade 18 in the tip 16 to cut the suture that has been captured within the tip 16 as described herein. The piston 30 includes a head 32 and a post 34 extending from the head 32. The head 32 includes a horizontally extending groove 36 that can engage the pusher 20. The piston 30 is coupled within the body 26 by a guide assembly 40 comprising a pair of opposing members 42 and 44 that are coupled together via a pair of live hinges 46 and 48 that allow easy mounting of the cutter 10. The opposing members 42 and 44 include a pair of grooves 52 and 54 that, when the opposing members 42 and 44 are folded over live hinges 46 and 48, as seen in FIG.4, will capture the piston head 32 and limit the movement of the piston head 32 along the longitudinal axis of the shaft 14 and actuate the pusher 20 in response to the movement of the lever 24. The corresponding snap-fit ​​elements 56 and 58 allow the opposing members 42 and 44 to be secured in place around the piston head 32 when folded over the live hinges 46 and 48, as seen in FIG. 4, which shows the opposing members 42 and 44 in the unfolded and then folded position. Referring to FIG. 4, the post 34 of the piston 30 extends from the guide assembly 40 to engage the lever 24 after the opposing members 42 and 44 are folded over the live hinges 46 and 48. As can be seen in FIG.3, the pivoting block 60 extends along the handle 12 so that driving the post 34 by the lever 24 will cause the piston head 32 to move longitudinally along the grooves 52 and 54.Since the piston head 32 is coupled to the pusher 20 by the groove 36, the movement of the lever 24 will drive the pusher 20 longitudinally along the axis 14 to actuate the blade 18 within the tip 16. The opposing members 42 and 44 also form a stop 62 within the handle 12 that limits the movement of the post 34 of the piston 30 and thus of the lever 24 so that the user cannot over-actuate the cutter 10. Referring to FIGS. 5 and 6, the shaft 14 is captured within the handle 12 and secured against movement by a plurality of retainers 70 in the guide assembly 40 of the handle 12 that interact with a pair of opposing notches 72 and 74 and a third terminal notice 76 on the shaft 14 that can couple the shaft 14 to the handle 12 and prevent rotation of the shaft 14 relative to the handle 12. Referring to FIG. 7, shaft 14 supports tip 16 which is contoured to define a tapered channel 90 that extends transversely through shaft 14 and narrows to a cradle 92. Channel 90 narrows from a first wider diameter (d1) that can capture a portion of taut suture to a second narrower diameter (d2) at the cradle 92. Second, the narrow diameter (d2) of the groove 303 is dimensioned to be smaller than the diameter of the untensioned suture. The channel 90 of tip 16 is oriented so that a user can slide tip 16 under a suture and then lift it to channel the suture through the tapered channel 90 and into the cradle 92. Referring to FIG. 8, the lower portion of tip 16 includes a longitudinally extending groove 96 that captures a tab 98 of the blade 18 to control the longitudinal movement of the blade 18.A sharp edge 100 of the blade 18 is positioned to move through the cradle 92 when driven by the pusher 20 and thus cut any sutures caught in it. Referring to FIG. 9, the pusher 20 includes a notch 102 that fits into a tab 104 on the blade 18. As shown in FIG. 10, the pusher 20 is oriented horizontally within the shaft 14 to engage the piston 30, with the blade 18 oriented vertically at the tip 16. This perpendicular relationship of the pusher 20 to the blade 18 allows the pusher 20 and blade 18 to be coupled within the shaft 14 using only the mechanical constraints of the shaft 14 and without additional fasteners or adhesives. Referring to FIG. 11, the tip 16 may include opposing locking surfaces 110 and 112 that extend into the channel 90 on opposite sides of the channel 90 and have upper portions that impart a slight twist to a suture while allowing the suture to slide into the channel, where it is released from the locking surfaces 110 and 112.Once the suture has moved completely into channel 90, the lower portions that block surfaces 110 and 112 prevent the taut suture from inadvertently moving out of channel 90. Referring to FIG. 12, in yet another embodiment, the tip 16 may include a channel cover 114 that is predisposed to cover the channel 90 but can slide longitudinally to allow and then prevent communication into and out of the channel 90 in response to contact with a suture. For example, when a suture comes into contact with the cover 114, a bearing surface 116 can provide a force that can cause the cover 114 to slide longitudinally toward the handle 12 to allow the suture to enter the channel 90. Once the suture has fallen into the channel 90 and then into the cradle 92, the cover 114 can return to its original position to trap the suture in the channel 90 until it is cut by the blade 18.This embodiment eliminates the requirement to have tension on the suture to retain the suture capture in cradle 92 of tip 16, and prevents an untensioned suture from unintentionally coming out of cradle 92, since no tension on the suture is required to keep the suture trapped inside cradle 92.

Claims

1. A suture cutter (10), comprising: a handle (12) having a body (26) and a lever (24) integrally formed with the body (26) such that the lever (24) is disposed to return to an initial position if the lever (24) is moved from the initial position to a user-operated position, a coupled shaft (14) extending longitudinally from the handle (12), a tip (16) having a channel (90) extending transversely through the tip (16) allowing access to a cradle (92), and a blade (18) movable within the tip (16) between a retracted position and an extended position in which the blade (18) passes through the cradle (92); and a pusher (20) interconnected to the blade (18), characterized by: a piston (30) positioned within the handle (12) and longitudinally movable within the handle (12) in response to the movement of the lever (24),wherein the body (26) includes a guide assembly (40) having a pair of opposing members (42, 44) with a corresponding pair of opposing grooves (52, 54) that align to form a guide for a piston head (32) (30), wherein the pair of opposing members (42, 44) of the guide assembly (40) are coupled together by a pair of live hinges (46, 48), and wherein the piston (30) includes a post (34) extending from the piston head (32) (30) to engage the lever (24); and a pivoting block (60) located in the body (26) in contact with the piston (30), so that the movement of the lever (24) against the post (34) of the piston (30) causes the head (32) of the piston (30) to move longitudinally within the guide of the guide assembly (40),wherein the pusher (20) is interconnected to the piston (30) such that movement of the lever (24) from the initial position to the actuated position causes the blade (18) to move from the retracted position to the extended position.

2. The suture stream of claim 1, wherein the pusher (20) is flat and horizontally oriented within the shaft (14).

3. The suture cutter (10) of claim 2, wherein the blade (18) is flat and vertically oriented within the shaft (14) to be at a right angle to the pusher (20).

4. The suture cutter (10) of claim 3, wherein the blade (18) has a tab (98) that is captured by a notch (102) in the pusher (20) to interlock the blade (18) and the pusher (20).

5. The suture cutter (10) of claim 4, wherein the shaft (14) includes a plurality of grooves (52,54) that are captured by a corresponding plurality of retainers (70) of the guide assembly (40).

6. The suture cutter (10) of claim 5, wherein the channel (90) of the tip (16) narrows inwardly from a first wider diameter to a second narrower diameter near the cradle (92).

7. The suture cutter (10) of claim 5, wherein the channel (90) of the tip (16) is contoured to discourage a suture from exiting the channel (90).

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