GB2506373A

GB2506373A - Bone and plate holding forceps

Info

Publication number: GB2506373A
Application number: GB201217230A
Authority: GB
Inventors: Tejas Kiran Yarashi
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-09-26
Filing date: 2012-09-26
Publication date: 2014-04-02
Also published as: GB201217230D0

Abstract

A bone and plate holding forceps comprises a barrel 1.4 in-between two hinged gripping members 1.18,1.3. The barrel 1.4 has a hole, which accommodates a rod 1.12. As the instrument is shut around the bone 1.20 the two gripping members 1.18,1.3 engage on the two surfaces of the bone 1.20. The rod 1.12 and pressure plate 1.2 perpendicularly push a bone plate 1.19 onto the bone 1.20. This gives a 3-point fixation of the bone 1.2 and the bone plate 1.19. Two spring plates 1.6 one on each handle can have a curved distal aspect 2.17 together creating an oval passage for the rod 1.12 to pass through.

Description

YARASHI BONE & PLATE HOLDING FORCEPS

Background

During Trauma & Orthopaedic operations an important part of fracture management is to bring the two fracture ends together and fix them with a plate and screws. Returning the two ends together allows the bone to heal well with the support of a stabilizing plate.

This part of the operation can be rather tricky for most long bone fractures of the body.

The plate needs to be held firmly to the bone, temporarily, to allow screws to be inserted through the plate and the bone. If not held firmly the fracture ends can displace and screws can be placed in the wrong position.

To avoid this happening there are many different types of bone and plate holding forceps, which do the job. Most of these forceps have to be applied in a way that strips soft tissue at the back of the bone. This may potentially reduce the blood supp'y to that part of the bone, which may affect the bone healing.

Most of the bone and plate holding forceps are placed so that one of the gripping arms is on the bone and the other is on the plate. Therefore tightening the plate onto the bone. However the bone is curved (convex) and the metal plate has a relatively straight surface. These forceps therefore cannot prevent the plate from slipping on the bone when the forceps are tightened. This seems to be a common problem using the currently available forceps.

A combination of both the above reasons makes these forceps difficult to use for the surgeon.

Statement of invention

The Yarashi Bone and Plate holding forceps contains two gripping arms to hold the bone perpendicular to the plate. The plate is subsequently pushed onto the bone firmly by a rod, which is moved through the centre of the hinge of the forceps through a barrel positioned in-between the hinge of the instrument.

Distal to the rod is an engaging mechanism, which makes contact with the plate.

The engaging mechanism independently moves in relation to the rod, so when the rod is moved distally the engaging mechanism pushes the plate on to the bone.

The mechanism of the rod coming through the centre of the hinge is the most innovative part of this instrument.

Normally forceps have handles, which are connected together at the hinge.

This instrument also connects at a hinge but the hinge also incorporates a barrel, which has a central hole through which a central rod can be moved distally and proximally. [Explained in more detail in the detailed description] This Yarashi Bone and Plate holding forceps is designed to be manufactured in different sizes so that it may be used in the plate fixations for fractures of all the long bones in the body (radius, ulna, humerus, femur, tibia, fibula] as well as the metacarpals of the hand, metatarsals of the foot and the phalanges of the hand and foot.

Advantages This forceps uses a 3-point mechanism of fixation.

The 2 gripping arms hold the bone tight at the top and the bottom. This allows the central rod and engaging mechanism to perpendicularly push the plate onto the bone. With the two gripping arms on either side and with a perpendicular force of the rod pushing on the bone plate the chances of the bone plate slipping on the bone are very low.

The other advantage is that there is minimal soft tissue stripping, as this forceps does not need access to the back of the bone.

Detailed description

(The indexed numbers in the brackets can correlate the description below with Figures 1 & 2.

The first number corresponds with the Figure number.) Yarashi Bone & Plate Holding Forceps The main part of the forceps is made up of two major bodies hinged at its distal third. Each Body can be divided into three portions: the long handle [1.10], distal third hinge (1.4. 2.4 & 2.21] and the distal gripping arm (1.18 & 2.1]. Both Bodies are flipped mirror images of each other.

The handle portion (1.10 & 2.16] is wider at the distal end (1.14) [proximal to the hinge] and tapers down to become less wide proximally.

The gripping arm contains jaws starting slightly proximal to its centre and continuing to its distal end (1.1 & 2.23]. The jawed portion of the gripping arm is curved inwards from centre to distal [1.1) to allow gripping of the bone. The gap between the two-jawed portions decreases from the centre to distal end. From proximal to centre the gap is wider and straight without jaws to allow inserdon ofa plate (1.19] in this gap. (Figure 1] The width of the proximal gripping arm and the distal portion of the handle have been designed to be larger (2.18 & 2.22] than the hinge portion of the Body (1.4, 2.4 & 2.21]. This allows a barrel [2.25] to sit in the gap between the two-hinged portions of the Bodies when brought together.

When all three parts (two hinged portions and barrel] are brought together the inside portion of the proximal gripping arm (1.3, 2.3 & 2.22] and distal aspect of the handle (1.14, 2.5 & 2.18] of one Body articulates with the hinged portion of the second Body [1.4] and the barrel (2.25].

The width of the articulating parts of the distal handle (2.18] and the proximal gripping arm [2.22] are equal. Both these are equal to the whole width of the barrel [2.25] and the thin hinge portion of the Body (1.4) 2.4, 2.21].

The barrel (2.25] contains a small screwed bolt [1.15 & 2.24] in the centre of each of its two flat surfaces. Each of these bolts penetrates through holes in the hinged portion of the Bodies (2.20]. Nuts (1.16, 2.2 & 2.19] are used to screw onto the bolts (2.24] on either side bringing the three parts (two hinged portions [1.4, 2.4 & 2.21] and barrel (2.25]] together in a stable construct at the same time creating a mechanism which allows the barrel to move independently of the hinge portions of the Bodies.

The barrel (2.25) contains a straight threaded hole, which penetrates proximal end of its curved surface and comes out of the opposite distal end of its curved surface.

A small rod (1.12 & 2.9) is inserted through this hole. The distal third of the rod contains a screwed thread (1.17 & 2.8], which is screwed through the hole in the barrel (2.25]. At the proximal end of the rod there is a cylindrical handle (1.7 & 2.13). This handle has a serrated! matted finish, which allows it to be gripped and used to screw the rod (2.9) in and out of the barrel. The cylindrical handle also contains various numbers of punched out holes (1.11 & 2.14) where a chuck can be inserted to tighten the rod further.

The distal end of the rod houses a cylindrical plate (1.2 & 2.27), which sits on the rod perpendicular to it. The flat surface opposite to the connection of the rod is serrated. This is the surface, which contacts the bone plate and aflows it to be gripped.

The cylindrical plate (2.27) is freely revolving in comparison to the rod to which it is fixed onto. This is achieved by inserting a screw (2.26) through a hole in the serrated surface of the cylindrical plate (2.27). The hole in the centre of the cylindrical plate is wider at its distal end and narrower at the proximal end. The shaft of the screw goes through this narrow end and only screws into the rod and not to the cylindrical plate thereby allowing the cylindrical plate to rotate freely.

The head of the screw is wider than the width of the narrow hole in the cylindrical plate but it fits comfortably through the wider hole of the cylindrical plate. This prevents the cylindrical plate to come out but yet rotate freely along its central axis. The purpose of this is to allow the rod (2.9] to be screwed tight when the cylindrical plate (2.27) is sitting on the bone plate preventing the cylindrical plate to rotate on the bone plate (1.19) itself.

When the instrument is closed i.e. when the handles are brought together as in Figure 1, the gripping arms (1.1) engage on the bone (1.20) with their jaws. This leaves a gap proximally where the rod (1.12) is screwed through the centre of the instrument. The cylindrical plate (1.2) on the distal aspect of the rod engages and perpendicularly pushes the bone plate (1.19) onto the bone as the rod (1.12) is screwed tighter. This configuration provides a 3-point stable fixation of the bone plate onto the bone.

Other features of this instrument are as follows: Both the handles have a thin spring plate (1.6 & 2.7) on their inside surfaces. The spring plates have a C' shape curve at its distal end (1.13 & 2.17]. The C' shaped curve of both spring plates meet at the same point to make an oval passage allowing the rod (1.12 & 2.9) to pass through. Both the spring plates sit and push on the rod equally to place it in the centre of the instrument.

These springs also work to open the instrument i.e. makes the distance between the gripping arms (1.18) and handles (1.10] automatically wider.

The ratchet mechanism to close the instrument is as follows: The proximal end of one handle has a small slit (2.15). The proximal end of the other handle has a metal piece (1.9 & 2.12), which houses a metal sheet (1.8).

The inside surface of the metal sheet is toothed (2.11). The metal sheet falls into the opposite handle's slit as in Figure 1. The slit engages with the toothed aspect of the metal sheet. The handle with the slit slides down the metal sheet engaging at every tooth. Once the slit is engaged to a tooth of the metal sheet the instrument cannot open unless the metal sheet is pulled out of the slit. The handle with the slit will only go one direction -towards the other handle. This acts as a ratchet mechanism allowing closure of the instrument with ease.

The handle with the metal piece housing the metal sheet also has a small spring sheet (2.10], which keeps the toothed meta' sheet constantly in the slit. This ensures the metal sheet doesn't fall out of the slit when engaged to it.

Claims

CLAIMS1. An instrument which functions by positioning and pushing a bone plate onto the desired portion of any bone in the body needing a plate fixation, comprising of two bodies coming together at its hinge portions where both the bodies' distal arms grip onto the two surfaces of the bone and handle arms to open and close the instrument, a barrel positioned in-between the hinge portions of the two bodies which allows the passage of a rod through the centre of the barrel, allowing the rod to perpendicularly push a bone plate onto the bone in the centre of the instrument while the distal arms are gripping onto the bone, two spring sheets, one on each handle of the instrument which keeps the rod central in the instrument.
2. The hinge portions of the two arms according to claim 1 are designed such that when both the hinge portions come together there is a gap between the two hinged portions of the instrument where a barrel can fit in.
3. The barrel according to claim land 2 comprises a means of attachment to both the hinge portions of the bodies whereby it can move independently to the hinged portions of the two bodies, has a passage allowing a rod to be inserted through where the rod can move distally and proximally in relation to the instrument in graded movements.
4. The combination of the hinge portion of the two arms according to claim 2 and the barrel according to claim 3 together make up a hinged joint.
5. The rod in claim 1 and 3 comprises a mechanism which allows it to be passed through the barrel so that it may move distally and proximally in relation to the instrument in graded movements in the centre of the instrument, proximal end of the rod comprising a means to help in manually moving the rod distally and proximally, distal end of the rod has means to engage with a bone plate allowing the plate to be pushed perpendicular to the plate's axis onto the bone when the rod is moved distally when the two gripping arms are fixed onto the two surfaces of the bone.
6. The distal end of the rod in claim 6 has an engaging mechanism, which is independently rotatable in relation to the rod so that when the rod is moved tighter distally the engaging mechanism can engage the bone plate and push it onto the bone perpendicular to the plate's axis.
7. Each handle arm contains a spring sheet, according to claim 1, which when met create a passageway allowing the passage of the rod through it therefore maintaining a central position of the rod in the instrument as it is moved distally and proximally and even when the instrument is opened and closed, it also aids in automatically opening the instrument by pushing the handles while pushing on the rod using its spring mechanism.