GB2575132A

GB2575132A - Surgical apparatus

Info

Publication number: GB2575132A
Application number: GB201818170A
Authority: GB
Inventors: Burrows Mike; Feam Martyn; Johnson John
Original assignee: Burcas Ltd
Current assignee: Burcas Ltd
Priority date: 2018-09-21
Filing date: 2018-11-07
Publication date: 2020-01-01
Also published as: WO2020058731A1; EP3852654A1; GB201815383D0; GB201818170D0

Abstract

A surgical blade with an elongate body 4 having a first and a second end with first 6 and second end faces, a longitudinal axis and at least one cutting edge. A first end portion has an end face, a longitudinally extending face, and a first and a second recess 26 in one or more surfaces of the first end portion, and the first recess (24) is located on substantially the opposite side of the longitudinal axis of the elongate body to the second recess. Preferably the recesses are in the narrow edge of the blade and are engaged by two pins 58 68, one of which is fixed 58 and the other is moveable 68 e.g. screw thread. The pin may be vibration resistant. The blade may have a stadium or rectangular cross section and may be planar throughout. Also claimed is a handle for use with the blade, preferably having the fixed and mobile pins. It may also have multiple slots (44 46 Fig 8) for receiving different blades at different orientations.

Description

SURGICAL APPARATUS

This invention relates to surgical apparatus and in particular to surgical blades and surgical handles which in combination can be used as surgical cutting instruments.

It is known that surgical cutting instruments have to be sterile at time of use. It is also known that it is desirable that such instruments need to be as sharp as they are intended to be when they are used. As a result, it is known for surgical cutting instruments to be wholly or partially disposable. This disposability is beneficial because it avoids the risk of cross infection between patients and bluntness of blades but has the disadvantage of the environmental cost of disposal of items that have only been used once. To balance these advantages and disadvantages it is known to dispose of the minimum amount of the apparatus as possible whilst seeking to avoid the risk of cross infection.

According to the present invention there is provided a surgical blade, a surgical handle, and a surgical cutting instrument comprising a blade and a handle.

According to a first aspect of the present invention there is provided a surgical blade comprising an elongate body, the elongate body having a first and a second end with first and second end faces respectively. The elongate body has a longitudinal axis, and at least one cutting edge, and is characterised in that a first end portion of the elongate body adjacent the first end of the elongate body is defined by the first end face and at least one longitudinally extending face, the first end portion defines a first and a second recess in one or more surfaces of the first end portion, and the first recess is located on substantially the opposite side of the longitudinal axis of the elongate body to the second recess.

In some embodiments of the present invention the first end portion of the elongate body is defined by one longitudinally extending face. In such embodiments the cross-section of the first end portion is circular, elliptical or of another curved shape where there are no defined edges to the longitudinally extending face.

Each of the first and second recess is defined by at least part of the first end portion of the elongate body. The recess can be created by moulding, stamping, drilling, cutting, grinding or other like processes appropriate to the material from which the elongate body is formed.

The first and second recesses may be of the same shape and dimension as each other or may be of different shapes or dimensions.

The first end portion of the elongate body is the portion of the elongate body which is adapted to be engaged with the handle of the second aspect of the present invention.

In some embodiments of the present invention the first end portion of the elongate body is defined by the first end face, and at least two longitudinally extending faces.

In some embodiments of the present invention the first end portion of the elongate body is defined by the first end face, and first, second, third and fourth longitudinally extending faces, the first and third longitudinally extending faces extend between the longitudinal edges of the second and fourth longitudinally extending faces, the distance between the longitudinal edges of the first longitudinally extending face is less than the distance between the longitudinal edges of either the second or fourth longitudinally extending faces, the distance between the longitudinal edges of the third longitudinally extending face is less than the distance between the longitudinal edges of either the second or fourth longitudinally extending faces, and the first recess is located in the first longitudinally extending face and the second recess is located in the third longitudinally extending face.

In some preferred embodiments of the present invention the first end portion of the elongate body has a rectangular cross section. In some embodiments the long dimension of the rectangle is significantly greater than the short dimension of the rectangle. This has the advantage that there is no danger of the first end portion rotating around the longitudinal axis of the elongate body when inserted into any appropriately configured receiving aperture in a handle. The receiving aperture may be a slot or other configuration appropriate for the receipt of the first end portion. A rectangular cross section for the first end portion of the elongate body has the further advantage that the first end portion of the elongate body may fit into an appropriately configured receiving aperture for the first end portion in either of two orientations. As such a member of the surgical team, if changing the blade of the cutting device does not need to present the blade to the handle in only one orientation.

In some embodiments of the present invention one or both of the first and second recess extends across the whole of the faces in which they are located. This is particularly convenient from a manufacturing point of view.

In other embodiments of the present invention the cross section of the first end portion of the elongate body may be substantially stadium shaped or other shape with a long first dimension and a second, perpendicular, short dimension in a plane substantially perpendicular to the longitudinal axis of the elongate body.

In some embodiments of the present invention the elongate body is comprised of a planar material throughout its length. In such embodiments, the elongate body can be cut out of a sheet material. Such elongate bodies will have considerable resistance to twisting around the longitudinal axis of the of the elongate body as well as considerable resistance to bending around an axis perpendicular to the plane of the material. Such rigidity is advantageous where it is important that cuts made by the surgical team occur where it is desired for them to be.

In some embodiments of the present invention the first end portion of the elongate body is comprised of a planar material and at least a portion of the remainder of the elongate body is a rod or a bar. In such embodiments the portion of the elongate body that is not the first end portion may be desired to have only a relatively small dimension in directions lateral to the longitudinal axis of the blade. In some embodiments of the present invention the material from which the elongate body is formed will be thicker when a portion of the elongate body is a rod or bar than when the blade is substantially planar. For example, the in embodiments where at least a portion of the elongate body is a rod or a bar the material from which the blade is formed may be 2mm thick in contrast to material of 1mm thick being used for embodiments where the blade is substantially planar.

In some embodiments of the present invention the at least one cutting edge is comprised of the second end of the elongate body. This configuration is partially useful if the cutting apparatus is to be used as a chisel or to cut into a part of the body or a prosthesis.

In some embodiments of the present invention at least one cutting edge is an edge formed on a protrusion extending from the elongate body, the protrusion is proximal to the second end, and the cutting edge on the protrusion tapers in thickness from a first thickness to a second lesser thickness in a direction away from the first end of the elongate body. In such embodiments the cutting edge faces away from the handle into which the blade may be inserted and the blade is used by pushing the blade. In such embodiments the second end of the blade may be used to guide the blade relative to a firm surface or prevent the cutting edge on the protrusion cutting closer to a surface than the distance between the second end of the blade and the cutting edge on the protrusion.

In some embodiments of the present invention at least one cutting edge is an edge formed on a protrusion extending from the elongate body, the protrusion is proximal to the second end, and the cutting edge on the protrusion tapers in thickness from a first thickness to a second lesser thickness in a direction away from the second end of the elongate body. In such embodiments the cutting edge faces toward the handle into which the blade may be inserted and the blade is used by pulling the blade. In such embodiments the second end of the blade may be used to guide the cutting edge relative to a firm surface.

In some embodiments of the present invention the elongate body is planar and the protrusion is substantially in the plane of the elongate body. In some other embodiments of the present invention the elongate body is planar and the protrusion extends out of the plane of the elongate body.

According to a second aspect of the present invention, a surgical handle suitable for use with a blade according to the first aspect of the present invention is provided in which the handle comprises a handle body, a blade receiving means, and a blade retention means, characterised in that the blade receiving means extends into the handle body, the blade receiving means is defined by one or more receiving means side faces and a receiving means base face and mouths through a surface of the handle, and the blade receiving means is dimensioned and configured so that a first end portion of a blade according to the first aspect of the present invention may be reversibly moved between an engaged position in which the first end portion of that blade is substantially within the receiving means and a detached position where the first end portion of the elongate portion of the blade is not in the receiving means, the receiving means side faces and a receiving means base face are in contact with the first end of the blade when the blade is in the engaged position, and the first and second recesses of the first end portion of the elongate body of the blade are within the blade receiving means when the blade is in the engaged position.

In some embodiments of the present invention the blade retention means is comprised of a fixed locking pin and a mobile locking pin, in which a portion of the fixed locking pin extends into the blade receiving means through a receiving means side face, the mobile locking pin is reversibly moveable between a retracted position in which the mobile locking pin does not extend into the blade receiving means and a protruding position in which a portion of the mobile locking pin extends into the blade receiving means through a receiving means side face, the fixed locking pin and the mobile locking pin are so located that when the first end of the elongate body of that blade according to the first aspect of the present invention is in contact with the base face of the blade receiving means at least a part of the fixed locking pin projects into one of the first or second recess of the first end portion of that blade, and movement of the mobile locking pin from the retracted position to the protruding position causes a part of the mobile locking pin to enter the other of the first or second recesses.

In these embodiments, the handle may be used in the following fashion starting for a situation where there is no blade engaged with the handle:

i. The handle is checked to see if the mobile locking pin is in the retracted position and the mobile locking pin moved to that position if it is not;

ii. The blade is introduced into the blade receiving means of the handle and moved to the engaged position so that one of the first or second recesses of the first end portion of the elongate body of the blade has a portion of the fixed locking pin introduced into that recess and the first end of the blade is in contact with the base face of the receiving means;

iii. The mobile locking pin is moved from its retracted position to its protruding position and a portion of the mobile locking pin introduced into the other of the first and second recesses;

iv. The blade is by prevented from moving from the engaged position to the detached position by the fixed and mobile locking pins projecting into the first and second recesses;

v. When it is desired to remove the blade from the handle, the mobile locking pin is moved from its protruding position to its retracted position results in a portion of the mobile locking pin being removed from one of the first and second recesses;

vi. The blade is then removed from the receiving means to the detached position.

Optionally, in step (iii) the movement of the mobile locking pin toward its protruding position pushes the blade toward the fixed locking pin and thus increases the portion of the fixed locking pin in the recess into which it extends.

In some embodiments of the present invention the mobile locking pin has a longitudinal axis and comprises a shaft with a pin end and a helically threaded portion, and the handle comprises a helically threaded bore, in which the pin end of the mobile locking pin is adapted to at least partially enter the first or second recess of the blade, the threads of the threaded portion of the mobile locking pin and the threaded bore of the handle are configured to intermesh, and rotation of the mobile locking pin around the mobile locking pin’s longitudinal axis will cause the mobile locking pin to move along the threaded bore in a direction dependent on the direction of rotation of the mobile locking pin. This embodiment is advantageous because the use of the helical thread to move the mobile fixing pin has the result that the location of the pin end can be accurately controlled and accidental movement of the mobile fixing pin away from its protruding position is unlikely.

In some embodiments of the present invention where the handle may be expected to encounter vibration as a result of the handle being hammered or from one or more other vibration sources the threads of the threaded portion of the mobile locking pin and the threaded bore of the handle are dimensioned and configured to be vibration resistant. An example of a vibration resistant thread configuration is taught in US patent no. US4540321A (Berecz).

In some embodiments of the present invention the mobile locking pin further comprises a second end, and the second end is configured to allow a user to use the second end to rotate the mobile locking pin around its longitudinal axis without the aid of a tool. The second end may be a knurled cylinder, or be otherwise configured to allow a user to readily rotate the mobile locking pin around its longitudinal axis.

In some embodiments of the present invention the handle body is a longitudinally extending body having a longitudinal axis. In some embodiments the handle body is substantially cylindrical. In some embodiments the threaded bore of the handle is substantially co-axial with the longitudinal axis of the handle.

In some embodiments of the present invention the handle further comprises at least a second blade receiving means.

In some embodiments of the present invention each blade receiving means is so located and orientated that the blade retention means may reversibly retain a blade according to the first aspect of the present invention inserted into any one of the blade receiving means.

In some embodiments of the present invention each blade receiving means has different dimensions to the or each other blade receiving means. This allows the handle to be used with blades which have first end portions of the elongate body that are differently sized from each other. For example, blades of different thickness as discussed in connection with the first aspect of the present invention above.

In some embodiments of the present invention the handle comprises two blade receiving means which are orientated at around 90° to each other. These blade receiving means may be differently dimensioned.

In some embodiments of the present invention the blade receiving means are longitudinally extending slots. The slots may be dimensioned and configured to receive the first end portion of one or more of blades according to the first aspect of the present invention.

According to a third aspect of the present invention there is provided a surgical cutting apparatus comprising at least one blade according to the first aspect of the present invention and a handle according to the second aspect of the present invention.

In some embodiments of the present invention there are provided a plurality of differently configured blades which may be interchangeably engaged with a single handle.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and I or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and I or features of any embodiment can be combined in any way and I or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

The present invention will be further described and explained by way of example and with reference to the accompanying drawings in which

Figure 1 shows a top view of a first embodiment of a blade according to the first aspect of the present invention;

Figure 2 shows a view of the blade of Figure 1 from the side;

Figure 3 shows an enlarged top view of the first end portion of the blade of Figure 1; Figure 4 shows an enlarged view of the second end portion of the blade of Figure 1;

Figure 5 shows a perspective view of a second embodiment of a blade according to the first aspect of the present invention;

Figure 6 shows a top view of a third embodiment of a blade according to the first aspect of the present invention;

Figure 7 shows a top view of a fourth embodiment of a blade according to the first aspect of the present invention;

Figure 8 shows a perspective view of a first embodiment of a handle according to the second aspect of the present invention;

Figure 9 shows a side view of the handle of Figure 8 without the inclusion of the blade retaining means;

Figure 10 shows a side view of the blade retaining means of the handle of Figure 8; and Figure 11 shows an embodiment of a surgical cutting apparatus according to the third aspect of the present invention.

In the description of the various embodiments of the present invention set out below elements common to the various embodiments are given the same reference numerals.

With reference to Figures 1 and 2, a surgical blade (2) is comprised of an elongate body (4) having a first end with a first end face (6) and a second end with a second end face (8). The blade (2) has a longitudinal axis (10) and a cutting edge (12). The blade is planar or flat and has substantially greater dimensions in two of the x, y, and z directions than the third dimension. The blade (2) is metallic, preferably formed from an appropriate grade of steel, and cut out from a sheet of that material. The blade may be treated to improve its qualities, such as hardness or surface finish. In other embodiments the blade may be of a plastic material, ceramic material or other appropriate material. The blade may be moulded or cast or otherwise formed, the method of formation being dependent upon the material to be used for the blade.

With reference to Figure 3, the blade (2) has a first end portion (14) which is, in the illustrated embodiment of the present invention, integral with the rest of the blade and of a larger dimension than the rest of the blade (2) in the plane of the blade (2) and perpendicular to the longitudinal axis (10). The first end portion (14) is defined by its two large faces (20, 22), the first end face (6) and the longitudinally extending faces (16,18) that extend between the two large faces (20, 22). The dimensions of the first end portion may be any appropriate dimensions. The thickness of the first end portion (14) may be may be any appropriate thickness.

One dimensioned embodiment of the first end portion (14) is rectangular with the larger dimension of the rectangle in the plane of the blade (2) and perpendicular to the longitudinal axis (10) being about 25.00 mm. The shorter dimension of the rectangle, which is parallel with the longitudinal axis (10) is about 13.75mm and the first end portion (14) has a thickness of about 1.00mm. It will be appreciated that this is just one example of the possible dimensions of the first end portion.

The first end portion (14) defines a first and second recess (24, 26) in the longitudinally extending faces (16, 18). The first and second recesses (24, 26) extend between the two large faces (20, 22) and have a trapezoidal shape with the longer of the parallel edges of the trapezoid forming the mouth in the edges (16, 18). The first and second recesses (24,26) are located on opposite sides of the longitudinal axis (10) and are equidistant from the first end face (6). Other shapes of recess may be employed in other embodiments of the present invention.

In the above mentioned dimensioned embodiment of the present invention, the dimensions and configuration of the recesses (24, 26) is that the recesses are isosceles trapezoids with the longer of the parallel sides being about 4.20mm long, the shorter about 3.24mm long, and the distance between the parallel sides being about 2.75mm. The edge of the mouths of the recesses (24, 26) closest to the first end face (6) of the blade (2) are around 2.90mm from the first end face (6).

With reference to Figure 4, proximal to the second end face (8) of the blade (2) is a protrusion (28) extending from the elongate body (4) in the plane of the elongate body. The edge of the protrusion (28) facing away from the second end face (8) has the form of a cutting edge (12). The cutting edge tapers from the thickness of the elongate body (4) where the cutting edge (12) is closest to the second end (8) to a sharp edge as the distance from the second end (8) increases.

The second end (8) is, in the embodiment of Figures 1 to 4, blunt. In other embodiments the second end (8) could also comprise a cutting edge.

The blade (2) of Figures 1 to 4 is adapted for cutting when movement of the blade is such that the handle is in front of the blade in the direction of travel of the blade.

With reference to Figure 5, the first end portion (14) of the blade (2) of Figure 5 is dimensionally the same as and has the same configuration as the first end portion of the blade (2) shown in Figures 1 to 4.

Proximal to the second end face (8) of the blade (2) of Figure 5 is a protrusion (28) extending from the elongate body (4). The protrusion extends out of the plane of the elongate body. The edge of the protrusion (28) facing toward the second end face (8) has the form of a cutting edge (12). The cutting edge tapers from the thickness of the elongate body (4) where the cutting edge (12) is closest to the first end face (6) to a sharp edge as the distance from the first end face (6) increases.

The second end face (8) is, in the current embodiment, blunt. In other embodiments the second end face (8) could also comprise a cutting edge.

The blade (2) of Figure 5 is adapted for cutting when movement of the blade is such that the blade is in front of the handle in the direction of travel of the blade.

With reference to Figure 6, a portion of the blade (2) is formed from a rod or bar (4a) which is integral with the first end portion (14) of the blade (2). The first end portion (14) of the blade (2) of Figure 6 is dimensionally the same and has the same configuration as the first end portion of the blade (2) shown in Figures 1 to 4 in the plane of the two large faces (20, 22). The thickness of the elongate body (4) may the same as that of the blades shown in Figures 1 to 5, but may be thicker. This will lend greater rigidity to the blade (2) to compensate for the blade (2) of Figure 6 being comprised of less material than the blades shown in Figures 1 to 5.

In the above mentioned dimensioned embodiment of the present invention the blade shown in Figure 6 has a thickness of around 2.00mm.

Proximal to the second end face (8) is a pair of protrusions (28a) extending from the rod or bar (4a). The protrusions extend from the rod or bar (4a) in opposite directions. The edge of each of the protrusions (28a) facing away from the first end face (8) has the form of a cutting edge (12a) and the cutting edge tapers from the thickness of the rod or bar (4a) where the cutting edge (12a) is closest to the first end face (6) to a sharp edge as the distance from the first end face (6) increases.

The second end face (8) is, in the embodiment of Figure 6, also a cutting edge (12).

The blade (2) of Figure 6 is adapted for cutting when movement of the blade is such that the blade is in front of the handle in the direction of travel of the blade.

The edges (30) of the protrusions (12a) that do not form a cutting edge are curved. The curvature of the edges (30) is convex. This has the result that after the blade (2) has been pushed / cut into a patient’s body, the curvature of the edges (30) minimises the likelihood of the patient’s body catching on the edges (30) of the protrusions (28a) when the blade (2) is withdrawn from the patient’s body.

With reference to Figure 7, a portion of the blade (2) is formed from a rod or bar (4a) which is integral with the first end portion (14) of the blade (2). The first end portion (14) of the blade (2) of Figure 7 is dimensionally the same as the first end portion of the blade (2) shown in Figures 1 to 4 in in the plane of the two large faces (20, 22). The thickness of the elongate body (4) may the same as that of the blades shown in Figures 1 to 5, but may be thicker.

This will lend greater rigidity to the blade (2) to compensate for the blade (2) of Figure 7 being comprised of less material than the blades shown in Figures 1 to 5.

In the above mentioned dimensioned embodiment of the present invention the blade shown in Figure 7 has a thickness of around 2.00mm.

The second end face (8) is a cutting edge (12). The blade (2) of Figure 7 is adapted for cutting when movement of the blade is such that the blade is in front of the handle in the direction of travel of the blade.

With reference to Figure 8, a surgical handle (40) is comprised of a cylindrical handle body (42) into which extend two blade receiving slots (44, 46). Blade receiving slots (44, 46) are differently dimensioned in that while both Blade receiving slots (44, 46) have rectangular mouths and the long dimension of the slots (44, 46) is the same for both slots, the short dimension of the rectangle is different for slots (44) and (46). The slots are parallel sided and extend from the mouths into the handle body (42).

In the above mentioned dimensioned embodiment of the present invention the cylindrical handle body (42) has a diameter of about 17.5mm, the mouth of the slot (44) has dimensions of around 27.85mm x 1,20mm, and the mouth of the slot (46) has dimensions of around 27.85mm x 2.20mm.

The blade receiving slots (44, 46) are of equal depth to each other and have opposing parallel sides. The depth of the slots (44, 46) is suitable to receive the first end portion (14) of a blade of Figures 1 to 7.

In the above mentioned dimensioned embodiment of the present invention the depth of the blade receiving slots (44, 46) is 13.75mm.

The blade receiving slots (44, 46) are orientated at around 90° to each other. And are positioned so that they intersect with each other in the region of the longitudinal axis of the cylindrical handle body (42).

With reference to Figures 9 and 10, the handle (40) has a bore comprising first and second end bores (50, 52) and a middle bore (48) extending between the first and second end faces (54, 56) of the handle body (42). The first and second end bores (50, 52) and middle bore (48) are co-axial with each other and the handle body (42).

The first and second end bores (50, 52) are of a larger diameter than the middle bore (48) and have a helical thread on the inner face of the bores. The middle bore (48) has a smooth inner face. The blade receiving slots (44, 46) intersect with each other in the middle bore (48).

A fixed locking pin (58) is comprised of a fixed pin shaft (60), a fixed threaded portion (62), and an end cap (64) in that order from one end to the other. Each of the fixed pin shaft (60), fixed threaded portion (62), and end cap (64) are wholly or substantially cylindrical and are co-axial with each other. The fixed pin shaft (60) is dimensioned so that it is a sliding fit within the middle bore (48) and the end of the fixed pin shaft (60) remote from the threaded portion (62) is frusto-conical. The frusto-conical end of the fixed pin shaft (60) is dimensioned and configured to be a close fit in the recesses (24, 26) of the blade (2) of any of Figures 1 to 7.

The fixed threaded portion (62) has a helical thread on its outer surface and the helical thread is dimensioned so that the helical thread can be a sliding fit with the helical thread of the first end bore (50) of the handle body (42). The end cap (64) is adapted to tightly abut the first end face (54) of the handle body (42) and to have the same outer diameter as the handle body (42).

The fixed locking pin (58) is fitted to the handle body (42) by inserting the fixed pin shaft (60) into the middle bore (48) through the first end bore (50) until the helical threads of the fixed threaded portion (62) and the first end bore (50) abut. The fixed locking pin (58) is turned around its longitudinal axis so that the helical threads of the fixed threaded portion (62) and the first end bore (50) intermesh and causes the fixed locking pin (58) to move along the middle bore (48) towards the second end (56) of the handle body (42). The fixed locking pin (58) is of an appropriate length that when the end cap (64) tightly abuts the first end face (54) of the handle body (42), the frusto-conical end of the fixed pin shaft (60) projects into the zone of intersection of the blade receiving slots (44, 46). The fixed locking pin (58) may be locked into position by use of a grub screw or other locking means (not shown).

A mobile locking pin (66) is comprised of a mobile pin shaft (68), a mobile threaded portion (70), and an end knob (72) in that order from one end to the other. Each of the mobile pin shaft (68), mobile threaded portion (70), and end knob (72) are wholly or substantially cylindrical and are co-axial with each other. The mobile pin shaft (68) is dimensioned so that it is a sliding fit within the middle bore (48) and the end of the mobile pin shaft (68) remote from the mobile threaded portion (70) is frusto-conical. The mobile pin shaft (68) is dimensioned so that it is a sliding fit within the middle bore (48) and the end of the mobile pin shaft (68) remote from the threaded portion (70) is frusto-conical. The frusto-conical end of the mobile pin shaft (68) is dimensioned and configured to be a close fit in the recesses (24, 26) of the blade (2) of any of Figures 1 to 7.

The mobile threaded portion (70) has a helical thread on its outer surface and the helical thread is dimensioned so that it is a sliding fit with the helical thread of the second end bore (52) of the handle body (42). The end knob (72) is knurled and adapted to abut the second end face (56) of the handle body (42) and to have the same outer diameter as the handle body (42). The end knob (72) is knurled so that a user can gain a good grip on the knob (72) and rotate it when required. It is important that a good grip can be obtained because, in use, the knurled knob (72) may be covered with slippery substances.

The mobile locking pin (66) is fitted to the handle body (42) by inserting the mobile pin shaft (68) into the middle bore (48) through the second end bore (52) until the helical threads of the mobile threaded portion (70) and the second end bore (52) abut. The mobile locking pin (58) is turned around its longitudinal axis so that the helical threads of the mobile threaded portion (70) and the second end bore (52) intermesh and the mobile locking pin (58) is caused to move along the middle bore (48) towards the first end (54) of the handle body (42). The mobile locking pin (66) is of an appropriate length that when the end knob (72) abuts the second end face (56) of the handle body (42) the frusto-conical end of the mobile pin shaft (68) projects into the zone of intersection of the blade receiving slots (44, 46) and is substantially the same distance from the proximal end of the fixed pin shaft (60) as the distance between the short parallel faces of the recesses (24, 26) in the first end portion (14) of the blade (2).

The longitudinal extent of the blade receiving slots (44, 46) is an extra length longer than the dimension of the large flat faces (20, 22) of the first end portion (14) of the blade (2) in a direction perpendicular to the longitudinal axis of the blade (2). The extra length is sufficient, when the mobile pin shaft (68) is not projecting into the zone of intersection of the blade receiving slots (44, 46), to allow the insertion of the first end portion (14) of the blade (2) into one of the blade receiving slots (44, 46) and the first end portion (14) of the blade (2) to be positioned so that one of the recesses (24, 26) has the frusto-conical end of the fixed pin shaft (60) at least partially within that recess.

In use, once the first end portion (14) of the blade (2) has been located in one of the blade receiving slots (44, 46) as described above, the user will use the end knob (72) to rotate the mobile locking pin to cause the mobile pin shaft (68) to enter the zone of intersection of the blade receiving slots (44, 46) and then the other of the recesses (24, 26) until the frustoconical end of the mobile pin shaft (68) is within the recess (24, 26) and has pushed the first end portion (14) of the blade (2) toward the frusto-conical end of the fixed pin shaft (60) until it is fully within that recess (22, 26). The end knob (72) will abut the second end face (56) when the first end portion (14) of the blade (2) is tightly held in position between the frustoconical ends of the fixed and mobile pin shafts (60, 68).

The threaded portions of the first and second end bores (50, 52) and the fixed and mobile threaded portions (62, 70) may be configured to be vibration resistant.

Claims

1. A surgical blade comprising an elongate body, the elongate body having a first and a second end with first and second end faces respectively, a longitudinal axis, and at least one cutting edge, characterised in that a first end portion of the elongate body adjacent the first end of the elongate body is defined by the first end face and at least one longitudinally extending face, and the first end portion defines a first and a second recess in one or more surfaces of the first end portion, and the first recess is located on substantially the opposite side of the longitudinal axis of the elongate body to the second recess.

2. A blade according to claim 1 in which the first end portion of the elongate body is defined by the first end face, and at least two longitudinally extending faces.

3. A blade according to claim 1 in which the first end portion of the elongate body is defined by the first end face, and first, second, third and fourth longitudinally extending faces, the first and third longitudinally extending faces extend between the longitudinal edges of the second and fourth longitudinally extending faces, the distance between the longitudinal edges of the first longitudinally extending face is less than the distance between the longitudinal edges of either the second or fourth longitudinally extending faces, the distance between the longitudinal edges of the third longitudinally extending face is less than the distance between the longitudinal edges of either the second or fourth longitudinally extending faces, and the first recess is located in the first longitudinally extending face and the second recess is located in the third longitudinally extending face

4. A blade according to claim 3 in which one or both of the first and second recess extends from the second to the fourth longitudinally extending face

5. A blade according to any of claims 1 to 4 in which the cross section of the first end portion of the elongate body is substantially rectangular or substantially stadium shaped in a plane substantially perpendicular to the longitudinal axis of the elongate body.

6. A blade according to any of claims 1 to 5 in which the elongate body is comprised of a planar material throughout its length.

7. A blade according to any of claims 1 to 5 in which the first end portion of the elongate body is comprised of a planar material and at least a portion the remainder of the elongate body is a rod or a bar.

8. A blade according to any of claims 1 to 7 in which at least one cutting edge is comprised of the second end of the elongate body.

9. A blade according to any of claims 1 to 8 in which at least one cutting edge is an edge formed on a protrusion extending from the elongate body, the protrusion is proximal to the second end, and the cutting edge on the protrusion tapers in thickness from a first thickness to a second lesser thickness in a direction away from the first end of the elongate body.

10. A blade according to any of claims 1 to 8 in which at least one cutting edge is an edge formed on a protrusion extending from the elongate body, the protrusion is proximal to the second end, and the cutting edge on the protrusion tapers in thickness from a first thickness to a second lesser thickness in a direction away from the second end of the elongate body.

10. A blade according to claim 9 or 10 in which the elongate body is planar and the protrusion is in substantially the same plane as the elongate body.

11. A blade according to claim 9 or 10 in which the elongate body is planar and the protrusion extends out of the plane of the elongate body.

12. A surgical handle suitable for use with a blade according to any of claims 1 to 11 in which the handle comprises a handle body, a blade receiving means, and a blade retention means characterised in that the blade receiving means extends into the handle body, is defined by one or more receiving means side faces and a receiving means base face, and mouths through a surface of the handle, and the blade receiving means is dimensioned and configured so that the first end portion of the blade may be reversibly moved between an engaged position in which the first end portion of the blade is substantially within the slot and a detached position where the first end portion of the blade is not in the slot, the slot side faces and a slot base face are in loose contact with the first end of the blade when the blade is in the engaged position, and the first and second recesses of the blade are within the blade receiving means when the blade is in the engaged position.

13. A handle according to claim 12 in which the blade retention means is comprised of a fixed locking pin and a mobile locking pin, in which a portion of the fixed locking pin extends into the blade receiving means through a receiving means side face, the mobile locking pin is reversibly moveable between a retracted position in which the mobile locking pin does not extend into the blade receiving means and a protruding position in which a portion of the mobile locking pin extends into the blade receiving means through a receiving means side face, the fixed locking pin and the mobile locking pin are so located that when the first end of the elongate body of the blade according to any of claims 1 to 11 is in contact with the base face of the blade receiving means at least a part of the fixed locking pin projects into one of the first or second recess of the blade, and movement of the mobile locking pin from the retracted position to the protruding position causes a part of the mobile locking pin to enter the other of the first or second recess of the blade.

14. A handle according to claim 13 in which the mobile locking pin has a longitudinal axis and comprises a shaft with a pin end and a helically threaded portion, and the handle comprises a helically threaded bore, in which the pin end of the mobile locking pin is adapted to at least partially enter the first or second recess of the blade, the threads of the threaded portion of the mobile locking pin and the threaded bore of the handle are configured to intermesh, and rotation of the mobile locking pin around the mobile locking pin’s longitudinal axis will cause the mobile locking pin to move along the threaded bore in a direction dependent on the direction of rotation of the mobile locking pin.

15. A handle according to claim 14 in which the threads of the threaded portion of the mobile locking pin and the threaded bore of the handle are dimensioned and configured to be vibration resistant.

16. A handle according to claim 14 or 15 in which the mobile locking pin further comprises a second end, and the second end is configured to allow a user to rotate the mobile locking pin around its longitudinal axis without the aid of a tool.

17 A handle according to any of claims 12 to 16 in which the handle body is a longitudinally extending body having a longitudinal axis.

18 A handle according to any of claims 14 to 17 in which In some embodiments the threaded bore of the handle is substantially co-axial with the longitudinal axis of the handle.

19. A handle according to any of claims 12 to 18 in which the handle further comprises at least a second blade receiving means.

20. A handle according to claim 19 in which each blade receiving means is so located and orientated that the blade retention means may reversibly retain a blade according to any of claims 1 to 11 inserted into any one of the blade receiving means.

21. A handle according to claim 19 or 20 in which each blade receiving means has different dimensions to the or each other blade receiving means.

22. A handle according to any of claims 19 to 21 in which there are two blade receiving means orientated at around 90° to each other.

23. A handle according to any of claims 12 to 22 in which the blade receiving means are longitudinally extending slots.

24. A surgical cutting apparatus comprising at least one blade according to any of claims 1 to 11 and a handle according to any of claims 12 to 23.

25. A surgical cutting apparatus according to claim 24 in which there are provided a plurality of differently configured blades which may be interchangeably engaged with a single handle.