Medical instrument

Abstract

An instrument with opposable jaws or shears, e.g. needle driving forceps or surgical scissors, comprises a pair of crossed arms 402, 404 pivotally connected at a box hinge, where one arm passes throug

Description

The present invention relates to a medical instrument and in particular, but not exclusively, to suturing needle holders, artery forceps, clamps, scissors, etc. which 5 include a hinge joint. As illustrated for example in Figures 1 and 2, a suturing needle holder 100 for holding a suturing needle for closing wounds typically includes a pair of arms 102,104 coupled together by a hinge 106. Each arm includes a jaw 108,110 at a io proximal end region for gripping a suturing needle and a handle, typically in the form of a loop 112,114 for respectively locating a thumb and finger in, at a distal end region for opening and closing the jaws using one hand, like using a pair of scissors. The hinge 106 is typically a box joint wherein a first one of the arms 102 is located in a slotted box cavity 111 of the second arm 104. The slotted box cavity extends is through the second arm from one edge to the other edge to define two walls 116,118 having substantially parallel and opposed inner surfaces 120,122. The first arm 102 includes a reduced region 123 defining substantially parallel and opposed outer surfaces 124,126 for sliding engagement with the inner surfaces 120,122 of the second arm 104. Coaxially aligned holes 127 are provided in the walls of the second 20 arm and the reduced region 123 of the first arm 102 for receiving a hinge pin 128 to couple the two arms together. The pin is typically pushed through the holes and welded to the walls 116,118 of the second arm 104 before being ground back so the outer surfaces of the second arm are flush and there is no or negligible visible sign of the pin. This is typically done to prevent snagging of sutures when tying off, to 25 prevent damage to gloves, etc. This type of ‘closed’ box joint provides a strong hinge but dirt and bacteria can accumulate, particularly around the hinge pin, and it is difficult to clean, sterilise and lubricate. Many medical instruments including a closed box hinge joint are therefore discarded after a single use which is a significant waste of material and energy and is environmentally unfriendly. 30 It is an aim of certain embodiments of the present invention to provide a medical instrument including a hinged box joint, such as a suturing needle holder, artery forceps, clamps, scissors, or the like, which is substantially open for efficient cleaning, sterilisation, lubrication and in turn re-use. 26 03 25 According to a first aspect of the present invention there is provided an instrument comprising: an elongate first member having a first jaw portion at a proximal end region 5 thereof; an elongate second member having a second jaw portion at a proximal end region thereof; and a box hinge comprising a hinge pin coupling the first member to the second member allowing the jaw portions to open and close with respect to each other, and io a first hinge portion of the first member defining first and second outer surfaces slidably engaged with laterally spaced apart first and second inner surfaces defining a slotted box cavity of a second hinge portion of the second member in which the first hinge portion is located, wherein the first hinge portion comprises a first through hole in which the 15 hinge pin is located and a recessed region extending substantially longitudinally with respect to a longitudinal axis of the first hinge portion and surrounding the first through hole for allowing a fluid into the box hinge and to the hinge pin, and wherein the first hinge portion comprises at least one second through hole spaced apart from the first through hole. 20 Optionally, the recessed region surrounds the at least one second through hole. Optionally, the first through hole is disposed on the longitudinal axis and the at least one second through hole is disposed above or below the longitudinal axis. 25 Optionally, the at least one second through hole is disposed at an angle of around 45 degrees above or below the longitudinal axis with respect to an axis of the first through hole. so Optionally, the at least one second through hole comprises two second through holes diametrically opposed to each other with respect to the first through hole. Optionally, the recessed region comprises a substantially flat base parallel with the outer surfaces of the first hinge portion. 26 03 25 Optionally, the recessed region comprises curved ends to define a capsule or ellipse shape. 5 Optionally, the instrument comprises a slot or channel extending from an outer edge of the first hinge portion and into the recessed region to allow a fluid into or out of the recessed region when the jaw portions are closed. Optionally, each side of the first hinge portion comprises a recessed region. io Optionally, an edge of the opening or recessed region is chamfered. Optionally, the first and second outer surfaces of the first hinge portion are defined by a reduced region of the first elongate member having a thickness which is less 15 than a thickness of the first jaw portion. According to a second aspect of the present invention there is provided a method of cleaning, sterilising or drying an instrument, comprising: rotating an elongate first member of the instrument with respect to an 20 elongate second member of the instrument about a hinge pin of a box hinge coupling the first and second members together to thereby open first and second jaw portions of the first and second members respectively; partially exposing a recessed region of a first hinge portion of the first member when the jaw portions are open, wherein the first hinge portion comprises a 25 first through hole in which the hinge pin is located and at least one second through hole spaced apart from the first through hole, and the recessed region extends substantially longitudinally with respect to a longitudinal axis of the first hinge portion and surrounds the first through hole, and wherein the first hinge portion defines first and second outer surfaces slidably engaged with laterally spaced apart first and 30 second inner surfaces defining a slotted box cavity of a second hinge portion of the second member in which the first hinge portion is located; and introducing a fluid into the recessed region and in turn into the box hinge and to the hinge pin. 26 03 25 Description of the Drawings Certain embodiments of the present invention will now be described with reference to the accompanying drawings in which: 5 Figure 1 illustrates a conventional suturing needle holder in a partially open state during normal use; Figure 2 illustrates the hinge region of the needle holder of Figure 1; io Figure 3 illustrates a suturing needle holder in an unassembled state; Figure 4 illustrates the needle holder of Figure 3 in an assembled and closed state; 15 Figure 5 illustrates the needle holder of Figure 4 in an open state; Figure 6 illustrates a suturing needle holder in an unassembled state; Figure 7 illustrates the needle holder of Figure 6 in an assembled and open state; 20 Figure 8 illustrates a suturing needle holder in an unassembled state; Figure 9 illustrates the needle holder of Figure 8 in an assembled and open state; 25 Figure 10 illustrates the inner member of a suturing needle holder when in an unassembled state; Figure 11 illustrates a cross section through a suturing needle holder in an assembled and closed state; 30 Figure 12 illustrates the inner member of a suturing needle holder according to an embodiment of the present invention when in an unassembled state; 26 03 25 Figure 13 illustrates a suturing needle holder according to an embodiment of the present invention including the inner member of Figure 12 in an assembled and open state; and 5 Figure 14 illustrates an alternative embodiment of the needle holder of Figures 12 and 13. Detailed Description io As illustrated in Figure 3, an instrument 300, in the form of a suturing needle holder, includes an elongate first member or arm 302 having a first hinge portion 303 pivotally coupled to a second hinge portion 305 of an elongate second member or arm 304. The first hinge portion 303 comprises a reduced region 323 defining substantially parallel and opposed outer surfaces 324,326 for sliding engagement 15 with opposed and parallel inner surfaces 320,322 defined by a slotted box cavity 311 of the second arm 304. Each arm 302,204 includes a jaw portion 308,310 at a proximal end region for gripping a suturing needle, and a handle portion (not shown) at a distal end region for opening and closing the jaw portions using one hand during a surgical operation. The reduced region 323 of the first arm 302 is located proximal 20 to the jaw portion 308 but it may be located anywhere between the proximal end region and the distal end region of the arm depending the application of the instrument. The reduced region 323 has a thickness which is less, i.e. reduced, compared to a thickness of the jaw portion and the handle portion or at least the remaining elongate portion of the arm extending towards the distal end region. 25 Aptly, the reduced region 323 has a length of around 22 mm along its longitudinal centre axis, is around 8.7 mm wide and has a thickness of around 1.8 mm. The opposed outer surfaces 324,326 of the reduced region 323 are substantially flat and planar. The jaw portions 308,310 may take any suitable form, such as plier-like including ridges, teeth or the like for gripping a suturing needle, hoop-like for holding 30 or squeezing a sponge, or including a blade for cutting an object. The reduced region 323 includes an elongate opening 325 located substantially centrally through the reduced region and oriented substantially longitudinally with respect to the arm. The elongate opening 325 has a length of around 22 mm and a 26 03 25 width of around 1.5 mm. The elongate opening 325 has rounded end surfaces to reduce / eliminate any stress concentrations in use. A circular through hole 327 having a diameter of around 2.5 mm, i.e. greater than the width of the elongate opening 325, is provided substantially centrally along the elongate opening 325 for 5 receiving a correspondingly sized hinge pin (not shown) to couple the first and second arms together whilst allowing them to rotate with respect to each other about a hinge axis defined by the pin. Corresponding coaxially aligned holes (not shown) are also provided in the walls of the second arm 304 for receiving respective end regions of the hinge pin which, as described above in relation to the prior art, is io typically pushed through the holes in both arms and welded to the walls of the second arm before being ground back so the outer surfaces of the second arm are flush and there is no, or at least negligible, visible sign of the pin. Alternatively, the pin may be fixed to the first hinge portion of the first arm and free to rotate in recesses or holes in the walls of the second hinge portion of the second arm. 15 The second arm 304 includes the slotted box cavity 311 extending from one edge of the arm to the other and defines the two walls 316,318 providing the substantially parallel and opposed inner surfaces 320,322. A pair of longitudinally spaced apart elongate openings 328,330 are provided in each wall and are aligned with 20 corresponding end regions of the elongate opening 325 in the reduced region 323 of the first arm 302. The hinge pin (not shown) is located between each pair of the elongate openings 328,330 and fixed by for example welding to the walls of the second arm 304 before being ground down to be flush with the outer surfaces of the arm. The first arm 302 is free to rotate about the hinge pin with respect to the 25 second arm 304. As illustrated in Figure 4, the elongate openings 328,330 in each wall of the second arm 304 are substantially aligned with the correspondingly shaped end regions of the elongate opening 325 in the first arm 302 when the jaws of the instrument are so closed. This allows a fluid, such as water, a steriliser or compressed air, into the elongate opening 325 of the first (inner) arm 302 and to the exposed opposed sides of the hinge pin in the slotted opening 325. As the arms are rotated apart about the hinge pin towards a fully open position as illustrated in Figure 5, the remaining circumferential surface of the hinge pin is exposed to cleaning fluid entering the 26 03 25 elongate slot 325 now from outside the second (outer) arm 304 and is thereby cleaned / sterilised. The outer surfaces of the reduced region 323 of the first arm 302 and the inner surfaces of the slotted box cavity 311 of the second arm 304 are also cleaned / sterilised by flushing through the slotted openings 328,330 in the walls of the 5 second arm 304 and the slotted opening 325 in the first arm 302. Rotating the arms with respect to each other also exposes different areas of the reduced region 323 to the elongate openings 328,330 in the second arm 304 and also acts to wipe the outer surfaces of the reduced region during cleaning. In the same manner, all surfaces can be dried by suitable means. Aptly, the edges of the elongate openings io 328,330 in the second arm 304 are chamfered and the edges of the elongate opening 325 in the first arm 302 could also be chamfered to encourage cleaning fluid into the slotted opening and to the hinge pin and between the sliding surfaces of the two arms. This arrangement provides relatively large bearing / sliding surfaces between the two arms and a substantially full width bearing surface on the hinge pin, 15 whilst providing efficient and effective cleaning and drying of all surfaces. As illustrated in Figure 6, an instrument 400, in the form of a suturing needle holder, includes a first arm 402 having a reduced region 423 defining substantially parallel and opposed outer surfaces 424,426 for sliding engagement with opposed and 20 parallel inner surfaces 420,422 defined by a slotted box cavity 411 of a second arm 404, i.e. in the same manner as the instrument described above. Each outer surface 424,426 of the reduced region 423 of the first (inner) arm 402 includes an elongate recessed region 425 oriented longitudinally and having parallel sides and rounded ends to define a capsule-shaped recessed region having a flat base which 25 substantially parallel with the outer surfaces 424,426. A circular through hole 427 is provided substantially centrally in the recessed region 425 for receiving a correspondingly sized hinge pin (not shown) to couple the first and second arms together whilst allowing them to rotate with respect to each other about a hinge axis defined by the pin. As illustrated in Figure 7, the ends of the recessed region 425 so are exposed when the arms 402,404 are rotated apart from the closed position towards the fully open position which allows cleaning fluid to enter the recessed region from both sides of the instrument and reach the hinge pin and sliding surfaces of the first and second arms. This arrangement provides improved cleaning, flushing and drying without reducing the strength of the components. 26 03 25 As illustrated in Figure 8, an instrument 500, in the form of a suturing needle holder, includes a first arm 502 having a reduced region 523 defining substantially parallel and opposed outer surfaces 524,526 for sliding engagement with opposed and 5 parallel inner surfaces 520,522 defined by a slotted box cavity 511 of a second arm 504, i.e. in the same manner as the instruments described above. The reduced region 523 of the first (inner) arm 502 includes a first through hole 527 provided substantially centrally in the reduced region 523 and substantially centrally between a pair of longitudinally spaced apart second through holes 531,533. The first through io hole 527 is circular for receiving a correspondingly sized hinge pin (not shown) to couple the first and second arms together whilst allowing them to rotate with respect to each other about a hinge axis defined by the pin. The second through holes 531,533 are aptly also circular and aptly have a larger diameter than the first through hole 527. Aptly, each second through hole has a diameter of around 4 mm. Each 15 second through hole is fluidly connected with the first through hole 527 by a longitudinally oriented recess or channel 534,536 provided on each outer surface of the reduced region 523. Aptly, the edges of at least the second through holes 531,533 and the channels 534,536 may be chamfered to encourage cleaning fluid into the holes and channels, to the hinge pin and between the sliding surfaces of the 20 two arms. As illustrated in Figure 9, as the arms are rotated apart about the hinge pin towards a fully open position, the second through holes 531,533 become exposed to allow cleaning fluid into the holes and between the sliding surfaces of the two arms. The cleaning fluid can also flow along the channels 534,536 to the hinge pin and the entire circumference thereof can be cleaned as the arms are rotated in 25 both directions with respect to each other about the hinge axis. The same applies when drying the instrument. This arrangement provides relatively large bearing / sliding surfaces between the two arms and a substantially full width bearing surface on the hinge pin, whilst providing efficient and effective cleaning and drying of all surfaces. 30 As illustrated in Figures 10 and 11, an instrument 600, in the form of a suturing needle holder, includes a first arm 602 having a reduced region 623 defining substantially parallel and opposed outer surfaces 624,626 for sliding engagement with opposed and parallel inner surfaces 620,622 defined by a slotted box cavity 611 26 03 25 of a second arm 604, i.e. in the same manner as the instruments described above. Each outer surface 624,626 of the reduced region 623 of the first (inner) arm 602 includes an elongate recessed region 625 oriented longitudinally and defining an ellipse. The recessed region 625 also has a flat base which substantially parallel 5 with the outer surfaces 624,626. Aptly, the edge of the recessed region is chamfered to encourage cleaning fluid into the recess 625 and between the sliding surfaces of the two arms. A circular through hole 627 is provided substantially centrally in the recessed region 625 for receiving a correspondingly sized hinge pin (650 in Figure 11) to couple the first and second arms together whilst allowing them io to rotate with respect to each other about a hinge axis defined by the pin. A pair of notches 628,630 extend outwardly from the hole 627 in opposed directions substantially along a longitudinal axis of the reduced region 623. Aptly, each notch is around 1.1 mm long and around 0.7 mm wide. As illustrated in Figure 11, these notches allow cleaning fluid and air to pass from one side of the recess region to the 15 other side and also to reach the hinge pin 650 located in the hole 627. The cleaning fluid or air contacts all the hinge pin as the arms are rotated between the closed and fully open positions whilst the notches act to wipe the surface of the hinge pin. The ends of the recessed region 625 are exposed when the arms 602,604 are rotated apart from the closed position towards the fully open position which allows cleaning 20 fluid to enter the recessed region from both sides of the instrument and reach the hinge pin and sliding surfaces of the first and second arms. This arrangement is similar to the instrument shown in Figure 6 but provides improved cleaning, flushing and drying without reducing the strength of the components. 25 As illustrated in Figures 12 and 13, an instrument 700 according to an embodiment of the present invention, in the form of a suturing needle holder, includes a first arm 702 having a reduced region 723 defining substantially parallel and opposed outer surfaces 724,726 for sliding engagement with opposed and parallel inner surfaces 720,722 defined by a slotted box cavity 711 of a second arm 704, i.e. in the same 30 manner as the instruments described above. Each outer surface 724,726 of the reduced region 723 of the first (inner) arm 702 includes an elongate recessed region 725 oriented longitudinally and defining an ellipse. The recessed region 725 also has a flat base which substantially parallel with the outer surfaces 724,726. Aptly, the edge of the recessed region is chamfered to encourage cleaning fluid into the 26 03 25 recess 725 and between the sliding surfaces of the two arms. A circular through hole 727 is provided substantially centrally in the recessed region 725 for receiving a correspondingly sized hinge pin (not shown) to couple the first and second arms together whilst allowing them to rotate with respect to each other about a hinge axis 5 defined by the pin. A pair of second through holes 731,733 are provided in the recessed region 725 spaced apart from the central through hole 727 and diametrically opposed at around 45 degrees from a longitudinal axis of the reduced region 723. Aptly the second through holes 731,733 are circular and have a smaller diameter than the central through hole 727. Aptly, each second through hole has a io diameter of around 1.25 mm. Aptly the edges of the second through holes are chamfered. As illustrated in Figure 13, the ends of the recessed region 725 are exposed when the arms 702,704 are rotated apart from the closed position towards the fully open position which allows cleaning fluid to enter the recessed region from both sides of the instrument and reach the hinge pin and sliding surfaces of the first is and second arms. The second through holes allow fluid to pass from one side of the reduced region to the other for improved cleaning and drying and distribution of fluid across the sliding surfaces. Aptly the recessed region is not visible during normal use positions of the instrument and the second through holes are never visible even in the fully open position. Disposing the second through holes 731,733 at an angle 20 above and below the longitudinal axis respectively, and more specifically the forward second through hole 733 below the longitudinal axis and the rearward second through hole 731 above the longitudinal axis, distances the holes away from a load path extending through the hinge region when a load is being applied at the handle regions and the jaws are clamping an object in use. Distancing the second through 25 holes away from the load path, desirably avoids or at least minimises any stress concentrations on or near to the load path and in turn potential fracture or fatigue cracking. Furthermore, locating the second through holes at around 45 degrees above and below the longitudinal axis, as illustrated, ensures optimal cleaning, draining and drying of the hinge region, particularly around the 0 degrees and 180 30 degrees positions wherein the longitudinal axis extends through the 90 degrees and 270 degrees positions. As illustrated in Figure 14, a slot or channel 750 is provided in each outer surface 724,726 of the reduced region 723 which extends from a front edge of the reduced 26 03 25 region proximal the jaw portion and into the recessed region 725. The slots or channels 750 open the recessed region 725 to atmosphere even when the jaw portions are closed which allows a fluid, such as sterilising steam, to enter the recessed region and in turn the hinge pin when the jaws are closed. The slots or 5 channels 750 may also aid cleaning and drying of the instrument in both open and closed states. Aptly, a slot or channel 750 may be provided on both or one side of the reduced region and / or at any location around the recessed region 725. Furthermore, one or more slots or channels 750 may be provided on each side of the reduced region 723. io The above dimensions for all described instruments are for example purposes only and can vary depending on the size and technical application of the instrument. Certain embodiments of the present invention therefore provide an instrument 15 including a hinged box joint, such as a medical instrument for cutting and dissecting, e.g. scissors or the like, or for grasping and holding, e.g. suturing needle holders, artery forceps, clamps or the like, wherein the box joint is configured to be efficiently cleaned, sterilised, lubricated and / or dried, and in turn re-used to thereby minimise material and energy waste and be environmentally friendly. 26 03 25

Claims

1. An instrument comprising:an elongate first member having a first jaw portion at a proximal end5 region thereof;an elongate second member having a second jaw portion at a proximal end region thereof; anda box hinge comprising a hinge pin coupling the first member to the second member allowing the jaw portions to open and close with respect to io each other, and a first hinge portion of the first member defining first and second outer surfaces slidably engaged with laterally spaced apart first and second inner surfaces defining a slotted box cavity of a second hinge portion of the second member in which the first hinge portion is located,wherein the first hinge portion comprises a first through hole in which the 15 hinge pin is located and a recessed region extending substantially longitudinally with respect to a longitudinal axis of the first hinge portion and surrounding the first through hole for allowing a fluid into the box hinge and to the hinge pin, and wherein the first hinge portion comprises at least one second through hole spaced apart from the first through hole.

202. The instrument according to claim 1, wherein the recessed region surrounds the at least one second through hole.

3. The instrument according to any preceding claim, wherein the first through hole 25 is disposed on the longitudinal axis and the at least one second through hole is disposed above or below the longitudinal axis.

4. The instrument according to claim 3, wherein the at least one second through hole is disposed at an angle of around 45 degrees above or below the30 longitudinal axis with respect to an axis of the first through hole.

5. The instrument according to any preceding claim, wherein the at least one second through hole comprises two second through holes diametrically opposed to each other with respect to the first through hole.26 03 256. The instrument according to any preceding claim, wherein the recessed region comprises a substantially flat base parallel with the outer surfaces of the first hinge portion.

57. The instrument according to any preceding claim, wherein the recessed region comprises curved ends to define a capsule or ellipse shape.

8. The instrument according to any preceding claim, comprising a slot or channel io extending from an outer edge of the first hinge portion and into the recessed region to allow a fluid into or out of the recessed region when the jaw portions are closed.

9. The instrument according to any preceding claim, wherein each side of the first is hinge portion comprises a recessed region.

10. The instrument according to any preceding claim, wherein an edge of the opening or recessed region is chamfered.20 11. The instrument according to any preceding claim, wherein the first and secondouter surfaces of the first hinge portion are defined by a reduced region of the first elongate member having a thickness which is less than a thickness of the first jaw portion.25 12. A method of cleaning, sterilising or drying an instrument, comprising:rotating an elongate first member of the instrument with respect to an elongate second member of the instrument about a hinge pin of a box hinge coupling the first and second members together to thereby open first and second jaw portions of the first and second members respectively;30 partially exposing a recessed region of a first hinge portion of the firstmember when the jaw portions are open, wherein the first hinge portion comprises a first through hole in which the hinge pin is located and at least one second through hole spaced apart from the first through hole, and the recessed region extends substantially longitudinally with respect to a longitudinal axis of35 the first hinge portion and surrounds the first through hole, and wherein the firsthinge portion defines first and second outer surfaces slidably engaged with laterally spaced apart first and second inner surfaces defining a slotted box cavity of a second hinge portion of the second member in which the first hinge portion is located; and5 introducing a fluid into the recessed region and in turn into the box hingeand to the hinge pin.26 03 25

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