GB2575657A - Forceps and method of manufacture and use - Google Patents

Abstract

A forceps for removing sutures, the forceps comprising a first arm 10 having respective proximal and distal ends 11,12, and a second arm 13 having respective proximal and distal ends 19,15. First and second arms 10&13 are joined such that the first arm’s distal end 12 moves towards the second arm’s distal end 15 in a first relative direction X to grip a suture. The first arm’s distal end 12 comprises a projection 16 extending from the first arm 10 in an extension direction, where the extension direction has a vector component that’s parallel to the first relative direction X, and which is opposite to the first relative direction X. Projection 16 may include a conical portion. Projection 16 may comprise a suture cutting edge to cut a suture. The cutting edge may raise the stress in a suture in use to thereby cut the suture. Respective proximal ends 11&19 of the first and second arms 10,13 are preferably joined at a hinge 17. The forceps may be for removing sutures used in ophthalmic, maxillofacial or plastic surgery. Also a method of manufacturing a forceps. It’s disclosed that the projection on the forceps is used to lift a suture.

Description

FORCEPS AND METHOD OF MANUFACTURE AND USE

The present disclosure relates to a forceps, preferably a forceps for removing sutures. The present disclosure also relates to a method of manufacturing a forceps and a method of using a forceps.

BACKGROUND OF THE DISCLOSURE

During surgery, sutures are used to close parts of the body which have previously been opened, for example by a scalpel to form an incision as part of the surgery. The sutures are manipulated by the surgeon to form stitches which hold the incision closed. The most common sutures in use today are nonabsorbable sutures which must be subsequently removed once the wound has healed.

Typically, sutures of a size range USP 6-0 to 11-0 are removed with an elongate implement having a small diameter, such as a needle. The needle tip is placed underneath the suture (between the patient anatomy and the underside of the suture) and moved upwardly in order to lift part of the suture from the anatomical surface. This usually results in a loop of suture being visible above the anatomy.

In one method of removal, once part of the suture has been lifted from the surface, the needle can be used to break the suture by tugging on it with the needle tip. Then, a separate instrument, such as a forceps, is used to grab the suture and pull it out.

In some types of surgery, a slip knot may be used to hold the stitches together when the stitches are formed. In this case, instead of breaking the suture, the needle is used to lift the part of the suture which has the slip knot from the anatomical surface in which the sutures are located, and the slip knot can be released by pulling on the free end. Then, as described above, the rest of the suture can be pulled with a separate instrument (e.g. a forceps) to remove the suture.

Such approaches to removing sutures can be used in all types of surgery, including ophthalmic surgery, maxillofacial surgery and plastic surgery.

Sutures used in ophthalmic surgery, maxillofacial surgery and plastic surgery may be in the size range as defined by the United States Pharmacopeia (USP) as 2-0 to 11-0. Larger numbers in this size range indicate sutures of smaller diameter. Particularly for ophthalmic and maxillofacial surgery, the sutures used are often toward the small end of this range, such as 9-0 USP or 10-0 USP. A 9-0 USP suture corresponds to a diameter of 0.03mm and a 10-0 USP suture corresponds to a diameter of 0.02mm. Using the European Pharmacopeia (EP) standard, a USP 9-0 suture corresponds to 0.3 EP size, and a USP 10-0 suture corresponds to 0.2 EP size.

When such sutures are used in ophthalmic surgery, a very small needle, such as a 25 gauge needle is used to lift the suture from the surface of the eye. The technique of breaking the suture with the needle is typically used in corneal transplant surgery (also known as penetrating keratoplasty). In another type of ophthalmic surgery which is used to lower the intraocular pressure of a patient’s eye, known as trabeculectomy surgery, the technique using a slip knot, as set out above, is typically used.

Using a sharp and narrow needle close to the surface of the eye to lift and/or cut a part of a suture requires great care and skill. If the needle were to slip, or the tip position is misjudged, the needle can damage the eye by, for example, perforating the cornea.

Further, the above techniques that involve using a needle have the disadvantage that separate implements are used for lifting the suture from the surface of the eye (e.g. a needle), and for removing the suture by pulling it out (e.g. the forceps). This can be inconvenient for the surgeon carrying out the procedure because it takes time to change between instruments, especially in surgery such as ophthalmic surgery where very fine movements are used and the surgery is typically done under a microscope. Changing the instrument may also increase the risk of user error and may cause delays because the second instrument might not be ready to use.

It would therefore be desirable to address at least one of these problems. Ideally apparatus and methods which improve safety and are easier and quicker to use are provided.

SUMMARY OF THE DISCLOSURE

The present disclosure provides a single instrument which is capable of being used to carry out the steps (raising the suture, breaking the suture and/or grabbing the suture) of the above-discussed procedure, which is also safer to use on the surface of the eye and which reduces the risk of damage to the eye. This allows the surgery to be completed more quickly and easily.

There is disclosed a forceps for removing sutures, said forceps comprising a first arm having a proximal end and a distal end and a second arm having a proximal end and a distal end. The first arm and the second arm are optionally joined such that the distal end of the first arm is configured to move towards the distal end of the second arm in a first relative direction to grip a suture. The distal end of the first arm optionally comprises a projection, and the projection may extend from the first arm in an extension direction. The extension direction optionally has a vector component which is parallel to the first relative direction, and which is opposite to the first relative direction.

Optionally, the projection includes a conical portion. This allows the suture to be easily lifted with the narrow end of the conical portion.

Optionally, the conical portion has a longitudinal axis, and the longitudinal axis of the conical portion is substantially parallel to the extension direction.

Optionally, the projection includes an intermediate portion. This increases the length of the projection, allowing the suture to be more easily lifted.

Optionally, the intermediate portion has a longitudinal axis, and the longitudinal axis of the intermediate portion is substantially parallel to the extension direction.

Optionally, the intermediate portion is located between the conical portion and the distal end of the first arm.

Optionally, the intermediate portion may be cylindrical or frustoconical.

Optionally, the projection further comprises a suture cutting edge configured to cut a suture. This allows the suture to be cut with minimal effort by the same instrument before being pulled out.

Optionally, the cutting edge includes a flat portion, the flat portion being a planar surface extending parallel to the extension direction.

Optionally, the planar surface of the flat portion is parallel to the localised elongate direction of the distal end of said first arm.

Optionally, the cutting edge includes first and second flat portions, each flat portion being a planar surface extending parallel to the extension direction, and wherein the first and second flat portions meet at a vertex to form the cutting edge. The vertex may optionally be on a side of the protrusion which faces away from the distal end of the first arm, or which faces the proximal end of the first arm. This allows the suture to be cut with minimal effort, force or tugging motion.

Optionally, the first and second flat portions, while preferably angled towards each other, do not meet at a vertex. The space between the first and second flat portions may not be sharp, which can reduce the risk of accidental cutting of the suture but nevertheless acts as a stress-raiser enabling a suture to be broken at that point.

Optionally, the planar surface of the first flat portion is parallel to the localised elongate direction of the distal end of said first arm and the planar surface of the second flat portion is perpendicular to the localised elongate direction of the distal end of said first arm. This allows the cutting edge to face upwards towards the operator when it is held at an angle to the anatomical surface.

Optionally, the cutting edge is located on the or a conical portion.

Optionally, the cutting edge is located on the or a intermediate portion.

Optionally, the cutting edge is configured to raise the stress in a suture in use to thereby cut the suture.

Optionally, the ratio of the length of the or a conical portion to the diameter of the or a conical portion is in the range of from 0.1 to 20, preferably from 1.5 to 5, more preferably from 2.0 to 3.5, and most preferably from 2.5 to 2.7.

Optionally, the ratio of the length of the or a cylindrical portion to the diameter of the or a cylindrical portion is in the range of from 0.2 to 8, preferably from 0.3 to 3 and more preferably from 0.5 to 1.5.

Optionally, the length of the projection is in the range of from 0.2mm to 10mm, preferably from 0.3mm to 2mm, and more preferably from 0.8mm to 1.2mm. Such a length may be particularly suitable for ophthalmic surgery or maxillofacial surgery. This length prevents the tip from deforming, bending or breaking off during manufacturing process and use, whilst allowing the projection to effectively lift the suture without damaging the anatomical surface.

Optionally, the proximal ends of the first arm and the second arm are joined at a hinge.

Optionally, the projection has a conical or frustoconical tip. This allows the suture to be lifted precisely from the anatomical surface.

Optionally, the projection has a hemispherical tip. This allows the suture to be lifted effectively without damaging the anatomical surface.

Optionally, the forceps is for removing sutures used in ophthalmic, maxillofacial or plastic surgery.

Optionally, the forceps is for removing and/or cutting sutures in the size range as defined by the United Stated Pharmacopeia (USP) as 2-0 to 11-0, and more preferably 9-0 to 10-0. Such sutures may be particularly suitable for ophthalmic, maxillofacial or plastic surgery.

Optionally, the projection includes a flat plate, wherein at least one edge of the flat plate extends in the extension direction.

Optionally, said at least one edge of the flat plate is sharp to act as a suture cutting edge configured to cut a suture.

There is also disclosed a method of manufacturing a forceps, the method comprising providing first and second arms, each arm having a proximal end and a distal end. The first and second arms are optionally joined such that the first arm is configured to move towards the second arm in a first relative direction to grip a suture. The distal end of the first arm optionally comprises a projection, and any such projection may extend in an extension direction. The extension direction optionally has a vector component which is parallel to the first relative direction, and which is opposite to the first relative direction.

Optionally, the method further comprises attaching the projection to the distal end of the first arm.

There is also disclosed a method of removing a suture, the method comprising lifting the suture from an anatomical surface using a projection on the distal end of a forceps, and pulling the suture using the arms of a forceps.

Optionally, the method further comprises cutting the suture using a cutting edge provided on the forceps.

The method of removing a suture can use any of the forceps as disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described, by way of non-limitative example only, with reference to the accompanying drawings, in which:

Figure 1 shows a top view of a forceps according to the present disclosure; Figure 2 shows a close-up view of the distal end of a first arm of the forceps, including a projection, according to the present disclosure;

Figure 3 shows a perspective view of the forceps as shown in Figure 1;

Figure 4 shows a perspective view of the distal end of the first arm in Figure 2 with a conical projection;

Figure 5 shows a schematic representation of the forceps distal end with a conical projection as shown in Figure 4;

Figure 6 shows a perspective view of a forceps distal end with a conical projection, the conical projection including a cutting edge formed by a flat portion;

Figure 7 shows a side view of the distal end of a first arm of the forceps with a projection including a stress raising cutting edge as shown in Figure 6;

Figure 8 shows a side view of the distal end of a first arm of the forceps with a projection including two flat portions which meet at a vertex to form a cutting edge;

Figure 9 shows a schematic representation of the distal end of the forceps with a projection including a stress raising cutting edge as shown in Figure 6;

Figure 10 shows a perspective view of a forceps distal end with a projection, the projection including a cylindrical intermediate portion and a conical tip portion;

Figure 11 shows a schematic representation of the forceps distal end with a projection, the projection including a cylindrical extension portion and a conical tip portion as shown in Figure 10;

Figure 12 shows a perspective view of the forceps as shown in Figure 11 lifting a suture;

Figure 13 shows a perspective view of the forceps as shown in Figure 11 pulling a suture free from a trabeculectomy slip-knot;

Figure 14 shows a perspective view of the forceps as shown in Figure 11 grasping the free end of a suture to pull it from the anatomy;

Figure 15 shows a perspective view of a forceps distal end with a projection, the projection including a cylindrical intermediate portion and a conical tip portion, and a stress raising cutting edge on the cylindrical intermediate portion;

Figure 16 shows a schematic representation of a forceps distal end with a projection, the projection including a cylindrical intermediate portion and a conical tip portion, and a stress raising cutting edge on the cylindrical intermediate portion as shown in Figure 14;

Figure 17 shows a perspective view of a forceps distal end with a projection, the projection including a frustoconical intermediate portion and a conical tip portion;

Figure 18 shows a schematic representation of a forceps distal end with a projection, the projection including a frustoconical extension portion and a conical tip portion as shown in Figure 17;

Figure 19 shows a perspective view of a distal end of a forceps according to the present disclosure with a projection, the projection including a frustoconical intermediate portion including a stress raising cutting edge and a conical tip portion:

Figure 20 shows a schematic representation of the forceps with a projection, the projection including a frustoconical intermediate portion including a stress raising cutting edge and a conical tip portion as shown in Figure 19;

Figure 21 shows a side view of the distal end of a first arm of the forceps with a projection including two flat portions with a bridge therebetween;

Figure 22 shows a perspective view of a suture being approached by the distal end of the forceps as shown in Figure 19;

Figure 23 shows a perspective view of the forceps as shown in Figure 19 lifting a suture;

Figure 24 shows a perspective view of the forceps as shown in Figure 19 breaking a suture;

Figure 25 shows a perspective view of the forceps as shown in Figure 19 where the arms of the forceps have been opened to allow a cut suture to be grasped;

Figure 26 shows a perspective view of the forceps as shown in Figure 19 where a cut suture is being pulled free;

Figure 27 shows a perspective view of the forceps as shown in Figure 19 pulling a lifted suture without breaking it;

Figure 28 shows a perspective view of a forceps with a projection, the projection being a knife-like flat plate;

Figure 29 shows a schematic view of a forceps with a projection, the projection being a knife-like flat plate as shown in Figure 28;

Figure 30 shows a side view of the configuration of Figure 29;

Figure 31 shows a perspective view of a distal end of a forceps similar to that shown in Figure 19, but with the conical portion formed as an oblique cone instead of a right cone;

Figure 32 shows a close up view of the forceps of Figure 31 lifting a suture; and

Figure 33 shows a close up view of the forceps of Figure 19 lifting a suture.

DETAILED DESCRIPTION

Figure 1 shows a plan (top) view of an example of a forceps according to the present disclosure and Figure 3 shows a perspective view of the same forceps. The forceps comprises a first arm 10 and a second arm 13. The first arm 10 has a proximal end 11 and a distal end 12, and the second arm 13 has a proximal end 14 and a distal end 15. The first arm 10 and the second arm 13 are joined such that the distal end of the first arm is configured to move towards the distal end of the second arm. For example, the proximal end 11 of the first arm 10 may be joined to the proximal end 14 of the second arm 13 at a hinge

17.

The hinge 17 may ideally be sprung so that, when no external force is applied to the arms, the two arms are separated, as shown in Figure 1. When an external force is applied to push the two arms together (e.g. a force applied by the fingers of a surgeon), the arms may move together, and when the force is released, the sprung hinge may cause the arms to return to their natural position as shown in Figure 1. Although an integral hinge is shown in Figure 1, the hinge may be of any suitable type such as a hinge that joins the first and second arms with a pivot. Furthermore, the hinge may be sprung by using a further component such as a compression or tension spring or resilient material.

The forceps is designed so that the distal ends of the first and second arms are brought together to be in contact when the arms are pushed together. In this way, items such as sutures may be gripped between the distal ends of the forceps’ arms. The distal end of each arm comprises at least the tip of the respective arm.

When a force is applied to push the two arms together, the distal end 12 of the first arm 10 moves in a first relative direction towards the distal end 15 of the second arm. This direction is shown as direction “X” in Figure 1. This movement allows a suture to be gripped between the distal end 12 of the first arm 10 and the distal end 15 of the second arm 13.

As shown in Figures 1 2, and 3, the first arm 10 comprises at its distal end 12 a projection 16. The projection 16 is relatively small compared to the overall longitudinal dimension of the forceps, and typically has a length smaller than 20 times the length of the first and second arms 10, 13, preferably 30 times smaller, more preferably 40 times smaller.

As shown in Figures 1 and 2, the projection 16 extends in an extension direction facing away from the second arm 13, and is at a right angle to the length direction along the first arm 10.

The extension direction of the projection is more generally defined as having a vector component which is parallel to the first relative direction. This means that the projection 16 extends, at least to some extent, along a line joining the distal tip of the first arm 10 to the distal tip of the second arm 13. Put another way, the projection has a vector component of extension that is parallel with the arrow X shown in Figure 1. The most preferred embodiment has the entire projection 16 substantially parallel with the first relative direction, but any component of extension being parallel is possible. Preferably the projection 16 extends at a right angle away from the distal end 12 of the first arm 10, but some variation from an exact right angle is possible, e.g. an 80 degree angle between the projection and the arm, a 50 degree angle between the projection and the arm or even a 30 degree angle between the projection and the arm.

The projection is generally of a form in which the tip is narrower than the base. A narrow tip allows the projection to be pushed under a suture more easily. As the projection is pushed underneath, the suture moves relatively along the length of the projection, and a widening base serves to pull the suture up out of the anatomy.

As shown in Figures 4 and 5, the projection 16 may have a cone shape.

The forceps as described above and as shown in Figures 1-3 allows sutures to be lifted from a surface of the anatomy using the projection 16. The projection is long enough to be able to slide under and lift, or “dig out”, a small portion of the suture, which typically lies flat on the anatomy in which the sutures are embedded. Also, the projection is short enough to limit the possibility of the projection itself piercing the anatomy to any great extent. Furthermore, the direction of extension of the projection 16 is such as to limit the opportunity for the projection 16 to pierce the anatomy as the projection passes underneath the suture and moves generally parallel to the surface of the anatomy. This contrasts with the prior art technique involving a 25 gauge needle, where it is difficult or impossible to present the needle parallel to the anatomy surface, and some angle of attack is usually present such that the needle tip encounters the anatomy at an acute angle rather than being parallel, increasing the possibility that the needle will penetrate the anatomy. The forceps disclosed here reduces this danger both by having a relatively short projection and by extending at least to some extent in a direction that is non-parallel to the forceps arm, thereby allowing a lateral movement of the forceps proximal end to effect a sliding of the projection under the suture in a direction generally parallel to the anatomical surface.

Once the suture has been lifted using the projection, the suture can be removed by moving the projection away from the suture, opening the arms of the forceps, grasping the lifted suture between the distal end 12 of the first arm 10 and the distal end 15 of the second arm 13 and pulling it away in a forceps action.

The dimensions of the projection 16 can be chosen such that they are adapted to the anatomy from which the suture is being removed. For example, when the above forceps is used in ophthalmic surgery, the projection 16 may be much shorter than the needles which are conventionally used to lift the suture from the surface of the eye. This lowers the risk of damaging the eye than if the lifting were carried out using a conventionally much longer needle. It also allows the lifting of the suture from the surface of the eye, and the removal by pulling the suture out of the eye, to be carried out using the same instrument, and in substantially a single operation.

Although in Figure 1, the projection 16 is shown as extending in a direction which is at a right angle to the length of the first arm 10, it need not be at this specific angle. The projection may extend from the distal end of the first arm in an extension direction, the extension direction having a vector component which is parallel to the first relative direction and which is opposite to the first relative direction. In other words, the projection 16 extends from the distal end 12 of the first arm in a direction which is away from the second arm, and is not parallel to the first arm. That is, the projection may extend in any direction in the hemisphere which is on the outside of the first arm 10 relative to the second arm 13, excluding a direction which is parallel to the first arm 10. Preferably, the projection 16 does not extend past the distal end 12 of the first arm 10 in the direction along the first arm 10.

As shown in Figures 2 and 4, the bottom of the projection 16 (i.e. the most distal part) is preferably provided flush with the distal end 12 of the first arm 10. This allows the projection to be positioned very close to the anatomy surface from which it lifts a suture, and thus allows easy lifting of the part of the suture. As shown in Figure 33, the bottom of the projection being provided flush with the distal end 12 of the first arm 10 means that, when the projection 16 is used to lift the suture 75, the distal end of the first arm is positioned away from the anatomy surface 100, preventing contact and possible damage to the anatomy. The projection may be very slightly recessed back from the edge of the distal end of the first arm 10, by for example up to 0.2mm. However, if the projection 16 were significantly recessed back from the edge of the distal end of the first arm 10, this may cause difficulty in lifting the suture because the portion of the distal end of the first arm may contact the surface of anatomy from which the suture is being lifted before the projection does.

In some circumstances, the suture may be cut after it is lifted and before the suture is pulled out. Thus, the projection may also include a portion which is configured to cut the suture. This will be outlined below. However, it is not always necessary to cut the suture after lifting, because the sutures may be knotted such that they can be released without cutting the suture.

The projection 16 may have different configurations and different dimensions depending on the application for which it is intended. These variations will now be set out. It will be appreciated that the features of each configuration may be combined with each other.

As shown in perspective in Figure 4 and schematically in Figure 5, the projection may comprise and/or substantially consist of a simple conical portion 51. The axis of the conical portion 51 may extend in the extension direction, as described above. The surface of the conical portion may be smooth (i.e. may not have a feature configured to cut a suture).

A smooth conical portion may be particularly suited to trabeculectomy surgery, in which a slip knot is used during the tying of the suture to form stitches. The suture can be lifted from the surface of the eye using the conical projection, which causes the slip knot to be released. Then, the untied suture can be removed from the eye by gripping it with the distal ends 12, 15 of the first and second arms 10, 13. Thus, in this procedure, it is not necessary to cut the suture before it is removed. Table 1 shows suitable dimensions for a conical projection for use in ophthalmic surgery, and in particular trabeculectomy surgery.

Table 1 - Ophthalmic Non-Cutting Trabeculectomy Cone
	Minimum	Maximum	Preferred
Cone Diameter (a)	0.1mm	1.0mm	0.3mm
Cone Length (b)	0.35mm	2.0mm	0.8mm
Cone Angle a	10°	60°	22°

Figure 6 shows a perspective view of a second configuration of projection 16 and Figure 7 shows a side view of the same configuration. Similarly to the first configuration, the projection comprises a conical portion 61. However, the projection also includes a suture cutting edge 63 configured to cut a suture. In the arrangement shown in Figures 6 and 7, the cutting edge is formed by the interaction of a flat portion 62 with the conical surface. This flat portion may create an edge 63 which acts as a stress raiser, which, when it comes into contact with a suture, raises the stress in the suture such that it breaks the suture.

Thus, the suture can be lifted using the tip of the projection, then slid along the projection to the cutting edge, which is located on the projection nearer to the distal end 12 of the first arm 10. When the part of the suture which has been lifted reaches the cutting edge, the stress in the suture is raised, and the suture is cut. Then, as described above, the suture can be removed by gripping it between the distal ends of the first and second arms, and pulling it out. The incorporation of the cutting edge on the projection means that the suture can be lifted and cut in one smooth motion, rather than being lifted using a needle, and cut in a separate action using the point of a needle or another instrument, and then removed in another separate action using a different instrument. This stress raising portion also obviates the need to tug on any of the apparatus to break the suture, which tugging is undesirable as it serves to tension the suture which may cause it to dig in to the anatomy.

As shown in Figure 8, the cutting edge may include two flat portions 64, 65, which meet at a vertex 66 to form the cutting edge. In other words, the two flat portions may form a “V” shape (a roof shape), with the tip of the “V” shape forming the cutting edge 66.

As shown in Figure 8, the planar surface of the first flat portion 64 is parallel to the first arm at its distal end and the planar surface of the second flat portion 65 is perpendicular to the first arm at its distal end. This means that, when the forceps is held at an angle of approximately 45 degrees to the surface of the eye or skin, the vertex 66 forming the cutting edge faces upwards, allowing easy cutting of the suture.

As most clearly shown in Figure 8, the angle between the two flat portions is ideally 90 degrees. However, it will be understood that other angles between the two flat portions may be provided without affecting the ability of the vertex therebetween to cut sutures. The planar surfaces can thus be arranged at other angles, e.g. in the range of 30 to 150 degrees, more preferably 60 to 120 degrees, yet more preferably 75 to 105 degrees.

The cutting edge of any embodiment may be serrated in order to aid easy cutting of the suture.

The above configuration including a cutting edge is particularly suited to situations in which the suture must be cut before it is removed from the anatomy. The stress raiser allows the suture to be cut with very little pulling force after the suture has been lifted from the surface of the anatomy using the projection.

The arrangements shown in Figures 6, 7 and 8 may be used to remove ophthalmic sutures used in corneal transplant surgery, where the suture is lifted from the surface of the eye, cut, and then pulled out from the eye. These arrangements are shown schematically in Figure 9. Suitable dimensions for use in the removal of corneal sutures are shown in Table 2.

Table 2 - Corneal Suture Cone with Cutting Flats
	Minimum	Maximum	Preferred
Cone Diameter (a)	0.1mm	1,0mm	0.35mm
Cone Length (b)	0.35mm	2.0mm	0.8mm
Cone Angle a	10°	60°	24°
Length of Cutting Flats (c)	0.2mm	1.0mm	0.25mm

The configuration of projection shown in Figure 9 can also be used in other types of general surgery which use larger sutures such as Orthopaedic Surgery, Abdominal Surgery, Trauma Surgery, Cardiothoracic Surgery and Head and Neck Surgery. Suitable dimensions for such a projection are shown in Table 3.

Table 3 - General Suture Cone with Cutting Flats
	Minimum	Maximum	Preferred
Cone Diameter (a)	1.0mm	4.0mm	2.0mm
Cone Length (b)	2.0mm	10.0mm	5.0mm
Cone Angle a	10°	60°	22°
Length of Cutting Flats (c)	1.0mm	5.0mm	2.0mm

Figure 10 shows a perspective view and Figure 11 shows a schematic representation of a third configuration of projection 16. Similarly to the first and second configurations, the projection comprises a conical portion 71. However, as shown in Figures 10 and 11, the projection 16 also includes a cylindrical intermediate portion 72. The cylindrical intermediate portion is located between the conical portion and the distal end 12 of the first arm 10. As shown in Figures 10 and 11, the projection may thus consist of an intermediate cylindrical portion and a tip conical portion.

Similarly to the configuration shown in Figure 4, a projection 16 including a conical portion 71 and the cylindrical intermediate portion 72 without a cutting surface (as shown in Figures 10 and 11) may be used in trabeculectomy surgery, or in other procedures where cutting of the suture is not required.

The additional length of the projection provided by the cylindrical portion 72 may allow easier lifting of the suture from the eye. Typical dimensions for a projection including a cylindrical portion and a conical portion for use in ophthalmic surgery are shown in Table 4.

Table 4 - Non-Cutting Trabeculectomy Cone and Cylindrical Intermediate Portion
	Minimum	Maximum	Preferred
Cone Diameter (a)	0.2mm	0.5mm	0.35mm
Cone Length (b)	0.2mm	1.0mm	0.7mm
Cone Angle a	10°	60°	27°
Cylinder Diameter (c)	0.3mm	0.7mm	0.35mm
Cylinder Length (d)	0.2mm	1.0mm	0.35mm

Figures 12, 13 and 14 show perspective views of the third configuration of projection 16 (as shown in Figures 10 and 11) in use in surgery (e.g. trabeculectomy surgery). Figure 12 shows the conical portion 71 being slid in direction Y underneath a suture 75. In this step, the surgeon positions the tip of the projection 16 (i.e. of the conical portion 71) adjacent to the suture 75, and slides the instrument in direction Y. This causes the suture 75 to move along the conical portion 71, thus pulling out the suture slightly as the cross-sectional area of the conical portion increases along its length, until the suture 75 reaches the cylindrical intermediate portion 72.

Figure 13 shows the suture 75 looped over the cylindrical intermediate portion 72 as it is pulled in direction Z until one end of the suture is pulled free of the surface of the anatomy (e.g. the eye).

Figure 14 shows the free end of the suture 75 being gripped between the distal ends 15 and 12 of the forceps arms 13 and 10 as it is pulled free from the eye in direction Z. In this step, the surgeon opens the arms of the forceps (by releasing his grip and allowing the arms to naturally spring open due to the inherent biasing of the arms into the open configuration), grasps the free end of the suture between the arms (by pushing them together), and pulls the instrument in direction Z, to untie the slip knot and remove the suture from the anatomy.

Figure 15 shows a perspective view and Figure 16 shows a schematic representation of a fourth configuration of projection 16. As shown in Figure 15, a projection 16 which includes a conical portion 71 and a cylindrical intermediate portion 72 (as shown in Figures 10 and 11) may also include a suture cutting edge 81 configured to cut a suture. The cutting edge may take any form, but is shown as being similar to that shown in Figure 8. i.e. a cutting edge produced by one or two flattened parts of the cylinder surface.

As described in relation to Figures 6, 7 and 8, using such a projection, the suture can be lifted from the surface of the anatomy in which the suture is embedded using the tip of the projection 16 (i.e. the conical portion 71), and then slid along the length of a projection onto the cylindrical intermediate portion 72 where the cutting edge is located 81. Then, as described as above in relation to Figures 6, 7 and 8, the cutting edge acts as a stress raiser which breaks the suture.

The configuration shown in Figures 15 and 16 may be particularly suitable for ophthalmic surgery, and in particular corneal surgery, such as corneal transplant surgery, where the sutures must be cut before they are pulled out. Table 5 shows suitable dimensions for use in corneal surgery.

Table 5 - Corneal Suture Cone and Cylindrical Intermediate Portion with Stress Raising Cutting Zone
	Minimum	Maximum	Preferred
Cone Diameter (a)	0.2mm	1.0mm	0.35mm
Cone Length (b)	0.2mm	1.0mm	0.8mm
Cone Angle a	10°	60°	24°
Cylinder Diameter (c)	0.2mm	1.0mm	0.5mm
Cylinder Length (d)	0.2mm	1.0mm	0.35mm
Length of Cutting Flats (e)	0.1mm	0.5mm	0.25mm

The configuration shown in Figures 15 and 16 may also be used in other types of surgery using larger sutures, where it is required to cut the suture before it is removed. Suitable dimensions for such a projection for use in general surgery are shown in Table 6.

Table 6 - General Suture Cone and Cylindrical Intermediate Portion with Stress Raising Cutting Zone
	Minimum	Maximum	Preferred
Cone Diameter (a)	1.0mm	4.0mm	2.0mm
Cone Length (b)	0.5mm	3.0mm	2.0mm
Cone Angle a	10°	60°	22°
Cylinder Diameter (c)	1.0mm	4.0mm	2.5mm
Cylinder Length (d)	0.5mm	7.0mm	3.0mm
Length of Cutting Flats (e)	1.0mm	5.0mm	2.5mm

Figure 17 shows a perspective view and Figure 18 shows a schematic representation of a fifth configuration of projection 16. As shown in Figure 17, the projection 16 includes a conical portion 91 and a frustoconical intermediate portion 92. The frustoconical intermediate portion is located between the conical portion and the distal end 12 of the first 10 arm 10. It will be understood that the frustoconical portion has a rhomboid shape when shown in cross-section, as shown in Figure 18. Thus, the shape of the projection 16 is similar to that of the projection shown in Figure 10, but with a frustoconical portion (which can be thought of as a flared cylinder or a truncated cone) replacing the cylindrical portion. Table 7 shows suitable dimensions of such a projection.

Table 7 - Non-Cutting Trabeculectomy Cone and Frustoconical Rhomboid Intermediate Portion
	Minimum	Maximum	Preferred
Cone Diameter (a)	0.1mm	1.0mm	0.35mm
Cone Length (b)	0.2mm	1.0mm	0.7mm
Cone Angle a	10°	60°	25°
Link angle β	160°	180°	170°
Frustoconical Diameter (c)	0.2mm	2.0mm	0.7mm
Frustoconical Length (d)	0.2mm	1.0mm	0.35mm

The fourth configuration shown in Figures 17 and 18 can also include a stress raising cutting edge as shown in perspective view in Figure 19 and in a schematic representation in Figure 20. The cutting edge located in the frustoconical portion of the projection 16 may be formed from two flat plates meeting at an apex as shown in Figure 8.

Alternatively, as shown in Figure 21, which is a side view of the preferred embodiment of the configuration with a frustoconical intermediate portion, the two flat plates 93 and 94 do not meet at an apex but are positioned with a space between them which leaves a bridge of the frustoconical intermediate portion 95. In other words, part of the curve of the frustoconical intermediate portion spans the gap between two edges of the flat plates, resulting in a smooth curve between the flat plates, rather than a sharp edge formed by a vertex. It will be understood that such an arrangement of flat plates with a bridge section between them could also be applied to the configuration shown in Figures 8 or 15, with the flat plates and bridge portion located on the conical portion or the cylindrical intermediate portion respectively.

The reduction in the area of contact between the suture and the projection in this bridge section 95 acts as a stress raiser that can still break a suture with a gentle lifting of the forceps. However, an advantage of this configuration is that the risk of an accidental or premature cutting of the suture is reduced. Thus, this configuration can be safely used for procedures where the suture must be cut and also procedures where the suture being removed must remain intact. Table 8 shows suitable dimensions for such a projection.

Table 8 - General Ophthalmic Cone and Frustoconical Rhomboid
	Minimum	Maximum	Preferred
Cone Diameter (a)	0.1mm	1.0mm	0.35mm
Cone Length (b)	0.2mm	1.0mm	0.7mm
Cone Angle a	10°	60°	25°
Length of Cutting Flats (e)	0.1mm	0.5mm	0.25mm
Frustoconical Length (d)	0.2mm	1.0mm	0.35mm

Figures 22, 23, 24, 25 and 26 show perspective views of the preferred embodiment of the fourth configuration of projection 16 (as shown in Figures 19, 20 and 21) in use removing a suture such as a corneal suture.

Figure 22 shows the projection 16 approaching the suture 96.

Figure 23 shows the conical portion 91 being slid in direction Y underneath the suture 96. In this step, the surgeon positions the tip of the projection 16 (i.e. of the conical portion 91) adjacent to the suture 96, and slides the instrument in direction Y. This causes the suture 96 to move along the conical portion 91, thus pulling out the suture slightly as the cross-sectional area of the conical portion increases along its length, until the suture 96 reaches the frustoconical intermediate portion 92.

Figure 24 shows the moment when the suture 96 passes over the stress raising section 95 and is broken. When the suture 96 reaches the stress raising section 95 on the frustoconical intermediate portion 92, no further movement of the instrument, or only a very slight movement of the instrument, is required to be carried out by the surgeon. This is because the stress raising section 95 raises the stress in the suture enough to break it without significant further pulling on the instrument.

Figure 25 shows the arms 10 and 13 of the forceps being opened as the forceps are moved to grasp the part of the suture 96 which has the knot 97. This is to ensure that the knot is not pulled into the eye when the suture is removed. In this step, the surgeon moves the projection away from the suture and opens the arms of the instrument so that the distal ends of the arms can grip the suture 96.

Figure 26 shows the suture grasped between the distal ends 12 and 15 ready to be pulled free from the anatomy. In this step, the surgeon grasps the suture between the two arms of the forceps, and can thus pull the suture from the anatomy.

Figure 27 shows the same fourth configuration as shown in Figures 19, 20 and 21 being used to remove another suture 98 that does not need to be broken, e.g. a trabeculectomy suture. By not sliding the suture as far as the stress raising section 95, the suture can safely be pulled free from the anatomy (e.g. the eye) in direction Z. In other words, the surgeon can, instead of sliding the instrument relative to the suture until it reaches the stress raising section 95, stop moving the instrument when the suture 98 is part of the way along the conical portion 91. This allows the same instrument to be used whether the suture is to be broken or not, and allows the surgeon to retain control over whether the suture is broken.

As shown in perspective view in Figure 28 or in schematic representation in Figure 29 and side view in Figure 30, the projection may additionally or alternatively comprise a flat plate. In other words, the projection 16 may be knife-shaped, or blade-shaped. At least one edge 107 of the projection 106 extends in the extension direction. As shown in Figures 28, 29 and 30, one edge of the flat plate may act as a suture cutting edge 108 which is configured to cut a suture. In this arrangement, the tip of the blade can be used to lift the suture, and then the cutting edge of the projection can be used to cut the suture. The shape of the top edge (e.g. as shown in Figure 29) can be curved, with the flat plate being wider at the point where it joins the distal end of the first arm than at the tip. This enables the projection to be pushed underneath the suture in a manner which lifts and eventually cuts the suture. Suitable dimensions for such a projection are shown in Table 9.

Table 9 - Multi-Purpose Knife Blade
	Minimum	Maximum	Preferred
Blade height at tip (a)	1.0mm	3.0mm	1.5mm
Blade height at forceps (b)	3.0mm	8.0mm	5.0mm
Blade Length (c)	5.0mm	20.0mm	12.0mm
Blade Width (d)	1.0mm	2.5mm	1.5mm

It will be noted that the shape of the conical portion shown in the preceding figures (e.g. Figure 5) is a right circular cone. That is, the base of the cone is circular, and the apex of the cone is directly above the centre of its base, and a cross-section through the apex of the cone along its axis is an isosceles triangle. However, as shown in Figures 30 and 31, the conical portion may also be formed in the shape of an oblique (or eccentric) circular cone. That is, the apex of the cone may not be directly above the centre of the base, and a crosssection through the apex of the cone along its axis is a scalene or right-angled triangle. It will be understood that such an oblique cone could be used in any of the projections described above.

The forceps may be manufactured in several ways. The forceps may first be produced without the projection, according to known methods. Then, the projection may be attached by providing (e.g. by drilling) a hole in the distal end of the first arm, inserting the projection, and then securing the projection in place by welding, soldering or any other suitable method. Alternatively, the projection may be attached by any of the above methods to the distal end of the first arm without first providing a hole in the distal end of the first arm.

Alternatively, the whole instrument may be cast as one piece. Portions of the forceps, including the projection, may be machined or otherwise, formed by milling, grinding, etching, and so forth.

These and other features and advantages of the present disclosure will be readily apparent from the detailed description, the scope of the invention being set out in the appended claims.

Any of the forceps as described herein can be used in a method of removing a suture from an anatomical surface. The suture, or a portion thereof, is lifted using the projection on the forceps. The lifting may be carried out with the tip of the projection, where the projection is narrowest. The suture may then slide along the projection towards the arm. Then, the suture is grasped between the distal ends of the two arms of the forceps, and is pulled out.

The lifting and pulling may be carried out in a single smooth motion without the forceps losing contact with the suture. In other words, the suture is lifted using the projection, and the forceps is moved so that the ends of the arms can grip the forceps and pull out the suture.

Alternatively, when a cutting edge is provided, after the suture is lifted using the projection on the forceps, the forceps is moved so that the suture slides along the projection to contact the cutting edge, which cuts the suture. Then, the suture can be pulled out. The cutting edge may be provided so that, when the forceps is held at a 45 degree angle to the anatomical surface (as is typical in such procedures), the cutting edge faces towards the operator. This allows the cutting of the suture to be effective and easily controlled. The present disclosure is set forth in various levels of detail in this application and no limitation as to the scope of the claimed subject matter is intended by either the inclusion or noninclusion of elements, components, or the like in the summary. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood that the claimed subject matter is not necessarily limited to the particular embodiments or arrangements illustrated herein.

The accompanying drawings are provided for purposes of illustration only, and the dimensions, positions, order, and relative sizes reflected in the drawings attached hereto may vary. The detailed description will be better understood in conjunction with the accompanying drawings, with reference made in detail to embodiments of the present subject matter, examples of which are illustrated in the drawings. Each example is provided by way of explanation of the present subject matter, not limitation of the present subject matter. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope of the present subject matter. Thus, it is intended that the present subject matter covers such modifications and variations as come within the scope of the appended claims and their equivalents.

In the foregoing description, it will be appreciated that the phrases “at least one”, “one or more”, and “and/or”, as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, counterclockwise, and/or the like) are used for identification purposes to aid the reader’s understanding of the present disclosure, and/or serve to distinguish regions of the associated elements from one another, and do not limit the associated element, particularly as to the position, orientation, or use of this disclosure.

Claims (25)

1. A forceps for removing sutures, said forceps comprising:

a first arm having a proximal end and a distal end; and a second arm having a proximal end and a distal end;

wherein the first arm and the second arm are joined such that the distal end of the first arm is configured to move towards the distal end of the second arm in a first relative direction to grip a suture;

wherein the distal end of the first arm comprises a projection, the projection extending from the first arm in an extension direction; and wherein the extension direction has a vector component which is parallel to the first relative direction, and which is opposite to the first relative direction.

2. The forceps of claim 1, wherein the projection includes a conical portion.

3. The forceps of claim 2, wherein the conical portion has a longitudinal axis, and the longitudinal axis of the conical portion is substantially parallel to the extension direction.

4. The forceps of claim 1, 2 or 3, wherein the projection includes an intermediate portion, optionally wherein the intermediate portion is a cylindrical portion or a frustoconical portion

5. The forceps of claim 4, wherein the intermediate portion has a longitudinal axis, and the longitudinal axis of the intermediate portion is substantially parallel to the extension direction.

6. The forceps of claim 4 or claim 5 when dependent on claim 2, wherein the intermediate portion is located between the conical portion and the distal end of the first arm.

7. The forceps of any one of the preceding claims, wherein the projection further comprises a suture cutting edge configured to cut a suture.

8. The forceps of claim 7, wherein the cutting edge includes a flat portion, the flat portion being a planar surface extending parallel to the extension direction.

9. The forceps of claim 8, wherein the planar surface of the flat portion is parallel to the localised elongate direction of the distal end of said first arm.

10. The forceps of claim 8 or 9, wherein the cutting edge includes first and second flat portions, each flat portion being a planar surface extending parallel to the extension direction, and wherein the first and second flat portions meet at a vertex to form the cutting edge.

11. The forceps of claim 10, wherein the planar surface of the first flat portion is parallel to the localised elongate direction of the distal end of said first arm and the planar surface of the second flat portion is perpendicular to the localised elongate direction of the distal end of said first arm.

12. The forceps of any one of claims 7 to 11, wherein the cutting edge is located on the or a conical portion.

13. The forceps of any one of claims 7 to 12, wherein the cutting edge is located on the or a cylindrical portion.

14. The forceps of any one of claims 7 to 13, wherein the cutting edge is configured to raise the stress in a suture in use to thereby cut the suture.

15. The forceps of any one of claims 2 to 14, wherein the ratio of the length of the or a conical portion to the diameter of the or a conical portion is 0.1 - 20, preferably 1.5-5, more preferably 2.0 - 3.5, and most preferably 2.5 - 2.7.

16. The forceps of any one of claims 4 to 15, wherein the ratio of the length of the or a cylindrical portion to the diameter of the or a cylindrical portion is 0.2 - 8, preferably 0.3 - 3 and more preferably 0.5 - 1.5.

17. The forceps of any one of the preceding claims, wherein the length of the projection is 0.2mm - 10mm, preferably 0.3mm - 2mm, and more preferably 0.8mm - 1.2mm.

18. The forceps of any one of the preceding claims, wherein the proximal ends of the first arm and the second arm are joined at a hinge.

19. The forceps of any one of the preceding claims, wherein the projection has a conical or frustoconical tip.

20. The forceps of any one of claims 1 to 18, wherein the projection has a hemispherical tip.

21. The forceps of any one of the preceding claims, wherein the forceps is for removing sutures used in ophthalmic, maxillofacial or plastic surgery.

22. The forceps of any one of the preceding claims, wherein the projection includes a flat plate, wherein at least one edge of the flat plate extends in the extension direction.

23. The forceps of claim 22, wherein said at least one edge of the flat plate is sharp to act as a suture cutting edge configured to cut a suture.

24. A method of manufacturing a forceps, said method comprising:

providing first and second arms, each arm having a proximal end and a distal end;

said first and second arms being joined such that the first arm is configured to move towards the second arm in a first relative direction to grip a suture; and said distal end of the first arm comprising a projection, wherein the projection extends in an extension direction; and wherein the extension direction has a vector component which is parallel to the first relative direction, and which is opposite to the first relative direction.

25. The method of claim 24, further comprising attaching the projection to the distal end of the first arm.