GB2624445A

GB2624445A - A surgical implement

Info

Publication number: GB2624445A
Application number: GB2217307.4A
Authority: GB
Inventors: Herre Jurgen; Seguna Ryan
Original assignee: Cambridge University Hospitals NHS Foundation Trust
Current assignee: Cambridge University Hospitals NHS Foundation Trust
Priority date: 2022-11-18
Filing date: 2022-11-18
Publication date: 2024-05-22
Also published as: GB202217307D0; WO2024105414A1

Abstract

The surgical implement comprises an open proximal end P a domed distal end D, a shaft 2 that extends between the ends and a lumen that extends along the shaft. The shaft has an opening 7 in its lateral wall. The diameter of the proximal end of the implement is equal to an overall diameter of the shaft so that a catheter having an inner diameter substantially equal to the overall diameter of the shaft may be passed over the proximal end of the implement and onto the shaft. The domed distal end may be an interference fit insert into the shaft. The lateral wall may comprise two opposing openings in the shaft and the distal end may have a ramp (figure 7) that connects the opening with the lumen

Description

A Surgical Implement

Technical Field

The present disclosure relates to a surgical needle for use in centeses procedures.

Background

Centeses procedures involve the surgical puncture of membranes for the drainage of fluid and/or air. Examples include: thoracenteses -a procedure in which a needle is inserted into the pleural space between the lungs and the chest wall to remove excess io fluid and/or air from the pleural space; paracenteses -a procedure in which excess fluid is removed from the peritoneal cavity in the abdomen; and pericardiocenteses -a procedure in which fluid is removed from the pericardial sac surrounding the heart. Each of these procedures are typically performed using a bevelled (i.e. sharpened) needle. This can lead to traumatic complications if the needle causes damage to blood vessels. Major bleeding can have fatal consequences and subjects to patients to other interventions such as surgery. Minor bleeding also portends significant morbidity and mortality, such as serious infections, increased hospital length-of-stay and chronic pain. Sharpened needle use also risks cutting through neurovascular structures or causing needle stick injury to clinicians.

Summary of the Invention

In a first aspect, there is provided a surgical implement for use in centeses procedures, the implement comprising: an open proximal end; a domed distal end; a shaft that extends between the distal and 25 proximal ends; and a lumen that extends along the shaft between the open proximal end and an opening in a lateral wall of the shaft; wherein an overall diameter of the proximal end of the implement is equal to an overall diameter of the shaft so that a catheter having an inner diameter substantially equal to the overall diameter of the shaft may be passed over the proximal end of the implement and onto the shaft.

Brief Description of the Drawings

Fig. 1 illustrates an implement according to a first embodiment; Fig. 2 is a detail view of a distal end of the implement of Fig. 1; Fig. 3 is a cross section taken along a longitudinal axis of Fig. 2; Fig. 4 illustrates an insert of the implement of Fig. 1; Fig. 5 illustrates an implement according to a second embodiment; Fig. 6 is a detail view of a distal end of the implement of Fig. 5; Fig. 7 is a cross section taken along a longitudinal axis of Fig. 6; Fig. 8 illustrates an insert of the implement of Fig. 5; Fig. 9 is a detail view of a distal end of a shaft of the implement of Fig. 5; and Fig. 10 shows the implement of Fig. 1 and a catheter for mounting on the implement.

Detailed Description

Fig. 1 illustrates an implement 1 for use in centeses procedures according to a first embodiment. Figs. 2 to 4 illustrate various features of the first embodiment.

The implement 1 comprises a domed distal end D, a proximal end P and a shaft 2 that extends between the distal and proximal ends D, P. Fig. 2 is a detail view of the domed distal end D of the implement. By 'domed' it is meant that the distal end D comprises a surface of revolution 3 defined by an open curve. That is to say, the domed end comprises a surface 3 defined by rotating an open curve around a longitudinal axis X-X of the implement. Said surface of revolution 3 is herein alternatively referred to as domed surface 3. By providing the distal end D of the implement 1 with a domed surface 3, the distal end D is shaped to splay tissue apart, rather than cut it, as will be explained further below. In the illustrated example, the open curve is substantially parabolic. 'Parabolic' is herein given its mathematical definition -that it is a symmetrical open plane curve formed by the intersection of a cone with a plane parallel to the cone's side. However, it will be appreciated that in other examples curves may be used that deviate from this mathematical definition. Indeed, any curve may be used, though certain geometric conditions are preferable. One such condition is that the curve is symmetrical about the longitudinal axis X-X of the implement 1. This ensures that the implement 1 adopts a straight path when pushed through tissue. An asymmetric domed end would likely cause the implement to deviate due to asymmetric loading of the domed end as it displaces tissue. A 'straight path' is one that is parallel to the implement's 1 longitudinal axis X-X and gives the operator absolute control of the implement's 1 direction. Equally preferable is that ends of the open curve comprise parallel tangents and that the diameter traced by said ends is equal to the diameter of the shaft 2. These geometric conditions ensure that the domed surface 3 forms a smooth, edge-free, transition with a surface of the shaft 2. 'Edge-free' means free of vertices. Such vertices might otherwise cause snagging on tissue during use of the implement 1. -3 -

Fig. 3 is a cross section of Fig. 2 projected onto a plane parallel to the longitudinal axis and illustrates a lumen 4 that extends along the shaft 2. The lumen 4 is enclosed by a lateral wall 5 of the shaft 2, which in the examples described herein is a tubular wall 5.

An outer surface of the tubular wall 5 forms part of an outermost surface 6 of the implement 1 along with the domed surface 3. An opening 7 extends through the lateral wall 5 to communicate the lumen 4 with an exterior of the implement 1. Therefore, during use, the opening 7 allows fluid and other bodily secretions to pass through the opening 7 and along the lumen 4. The lumen 4 terminates at an opening 8 in an end _to face of shaft 2 at the proximal end P. In this way, the lumen 4 extends substantially along the full length of the shaft 2 to carry said fluid and secretions outside of a body into which the implement 1 has been inserted.

In the example of Fig. 3, the opening 7 is a through hole 7 in the shaft 2 so that it /5 comprises two openings 7', 7" in the lateral wall 5 on opposite sides of the longitudinal axis X-X. Having two openings 7', 7" ensures that the implement 1 continues to extract fluid and secretions, even if one becomes blocked. A further benefit of two openings 7', 7" is an improved flow rate along the lumen 4 than if only a single opening were used. This is especially true where the fluid or secretions is particularly viscous. Each opening 7, 7' may have a diameter of between about 0.75mm and about imm, or between about 0.8mm and 0.9mm. In a specific example, the diameter of the openings 7,7' may be about 0.838mm.

Also in the present example, the domed distal end D and the shaft 2 are formed as separate components with the domed distal end D being provided by an insert 9, shown in Fig. 4 in isolation. The insert 9 comprises a first cylindrical section 10 with an outer surface 10' that intersects the domed surface 3. Put another way, the diameter of the domed surface 3 is equal to the diameter of the outer surface 10' of the first cylindrical section lo where the two surfaces 3, 10' meet. This means that a step-free transition is provided between the domed surface 3 and the outer surface 10' of the first cylindrical section 10. As with being 'edge-free', 'step-free' means the insert 9 is free of vertices that might otherwise snag on tissue during use of the implement 1. The insert 9 further comprises a second cylindrical section if that extends concentrically from the first cylindrical section 10 opposite the domed surface 3. An overall diameter of the second cylindrical section 11 is less than an overall diameter of the first cylindrical section 10, but equal to an internal diameter of the lateral wall 5. Therefore, when assembled, the -4 -second cylindrical section 11 is received within a distal end of the lateral wall 5 and retained therein by interference fit. The outer diameter of the first cylindrical section 10 and the outer diameter of the lateral wall 5 are the same so that the outermost surface 6 of the implement 1 is also edge and step free where the insert 9 meets the shaft 2.

Figs. 5 illustrates an implement 1' for use in centeses procedures according to a second embodiment in which like features retain the same reference numbers. Figs. 6 to 9 illustrate various features of the second embodiment. In the second embodiment, the domed distal end D and the shaft 2 are again formed as separate components, with the _ft) domed distal end D being provided as an insert 9'. However, in the second embodiment the interface between the insert 9' and the shaft 2 differs according to the following.

Fig. 7 illustrates a section of the distal end D. A ramp 12 is provided between the lumen 4 and the opening 7. The ramp 12 connects a surface 13 of the lumen 4 with a distal /5 edge 14 of the opening 7 to provide a smooth transition between the lumen 4 and the opening 7. This allows a guidewire to be threaded through the lumen 4 and out of the opening 7 during a Seldinger' type procedure, which will be explained further below. In one example, the ramp 12 comprises a curve of constant radius.

Fig. 8 illustrates the insert 9' in isolation. The insert 9' comprises the same features retaining the same reference numbers as the insert 9 with the exception that the second cylindrical section 11 of the insert 9 is omitted and, instead, the ramp 12 projects from the first cylindrical section 10. The ramp 12 is a curved surface of the insert that connects an edge 14 of the first cylindrical section with a proximal most edge 15 of the insert 9'.

Fig. 9 is detail end view of the shaft 2. A slot 16 extends in from a distal end of the shaft 2, giving it a forked end. By 'forked end', it is meant that the slot leaves two lobes 17 of the lateral wall 5 of the shaft 2 either side the slot 16. Cut outs 18 are provided either side the ramp 12 to receive the lobes 17 and allow the shaft 2 and insert 9' to be assembled in a dovetail fashion, as shown in Fig. 6. When assembled in this way, an outer surface 19 of the ramp 12 combines with outer surfaces 20 of the lobes to form part of the outermost surface 6 of the implement 1'. The outer surface of the ramp 12 has curvature of equal diameter to that of the shaft 2 so that the ramp 12 is received between the lobes 17 with no effect on the curvature of the shaft 2. On the other side of axis X-X to the outer surface 19 of the ramp 12, the edge 14 of the first cylindrical -5 -section 10 is received within an edge 21 of the slot 16 so that said edges 14, 21 together define the opening 7. Therefore, the opening 7 of the present embodiment is not formed wholly within the lateral wall 5, but is defined by the ramp 12 and the slot 16. In this way the implement 1' of this embodiment may be manufactured in fewer machining steps. In examples, the ramp 12 may have a radius of curvature of between about imm and about 1.5mm, or between about 1.2MM and 1.3mm. In a specific example, the radius of curvature of the ramp 12 is about 1.27mm.

The implement of the first and second embodiments 1, f can be used in centeses procedures, including thoracenteses, paracenteses and pericardiocenteses. The _ft) implement of the second embodiment 1' can additionally be used for a Seldinger' type procedure explained below. However, it shall be appreciated that the surgical application of the implement 1, 1' is not limited to these procedures and may be used in any percutaneous procedure where the introduction of the lumen 4 into a target area is desired. Other applications may include procedures such as CT/US-guided /5 percutaneous drainage of deep-seated abscesses/haematomas and CT/US-guided drain insertion.

By way of example, the first embodiment may be used in a thoracenteses procedure according to the following. The implement 1 is prepared for the procedure by passing a catheter over the proximal end P of the implement iso that the catheter is mounted over the proximal end P. After administration of local anaesthetic to the patient, a small, 3-mm, superficial skin incision is made to facilitate insertion of the implement 1 through the skin. The incision is very superficial and does not go deep into the muscle layers. The implement 1 is then inserted through the incision and into a target area, which in a thoracenteses procedure is the pleural cavity. Rather than cutting its way into the pleural cavity, the domed distal end D of the implement splays subcutaneous tissue, thereby mitigating or even eliminating the risk to intercostal vessels and nerves. The implement 1 will be in contact with body tissues and fluids for a relatively short period of time, in the range of seconds. This is the time it takes for the implement ito traverse the various tissue layers to access the target site. In other words, to traverse the intercostal space to access the pleural cavity. Correct placement of the implement 1 within the target site is confirmed by aspiration of air/fluid from the pleural cavity through the opening 7 and along the lumen 4. In other words, the opening 7 in the lateral wall of the implement 1 allows for drainage of the air/fluid through the lumen 4 once the implement 1 is in the target space. Thereafter the catheter is advanced into the pleural cavity to connect the implement 1 to a drain. The catheter is progressed sleeve- -6 -like along the implement iand into the pleural cavity. A catheter 22 and implement 1 are shown in Fig. 10. The catheter 22 is illustrated adjacent the proximal end P of the implement ito allow the catheter 22 to be passed over the proximal end P and progressed into the target area. It is desirable that an internal diameter of the catheter 22 is substantially equal to the external diameter of the lateral wall 5 to allow catheter 22 to be passed over the lateral wall 5 and into the target area without damage to tissue. Following the procedure, the implement i is removed from the patient.

By way of another example, the second embodiment may be used according to the Seldinger technique as follows. Again, following administration of local anaesthetic, a small, 3-mm, superficial skin incision is made to facilitate insertion of the implement through the skin and into a target area. However, the objective of the Seldinger technique is to facilitate placement of either a short-term chest drain or a longer-term indwelling drain. In order to do this, a guidewire is inserted into the lumen 4 through /5 the proximal end P of the implement f. The ramp 12 directs the guidewire out of the opening 7 and into the target area. The implement I is then removed over the guidewire so that the guidewire may serve to allow the placement of a chest drain along the guidewire for feeding into the target area.

Irrespective of whether the first or second embodiment 1, is used in any percutaneous surgical procedure, a key benefit is that the domed distal end D eliminates the risk of damage to vessels and nerves that may lay between the initial incision and the target area.

Another advantageous aspect of either embodiment 1, is that an overall diameter of the proximal end P of the implement 1, I is equal to an overall diameter of the shaft 2 so that a catheter having an inner diameter substantially equal to the overall diameter of the shaft 2 may be passed over the proximal end P of the implement 1, I and onto the shaft 2 for insertion into the target area.

In the above described embodiments 1, 1', the implement 1, may be between 5omm and i5omm long, or between 80mm and i3omm long or between loomm and nomm. In a specific example, the implement is about nomm long. The diameter of the shaft 2 may be between about imm and about 1.5mm, or between about 1.2MM and 1.3mm. In a specific example, the diameter of the shaft is about 1.27mm. -7 -

in the above described embodiments 1, 1', the opening/openings 7,7' are located relatively close to the distal end D. For example, the centre of each opening may be between 2MM and 4mm from the distal end D, measured parallel to the implement's 1 longitudinal axis X-X. In a specific example, the centre of each opening 7, 7' may be about 3mm from the distal end D. Any distance measured from the distal end D is herein the distance from the very distal most point of the implement 1, 1'. -8 -

Claims

Claims 1. A surgical implement for use in centeses procedures, the implement comprising: an open proximal end; a domed distal end; a shaft that extends between the distal and proximal ends; and a lumen that extends along the shaft between the open proximal end and an opening in a lateral wall of the shaft; wherein an overall diameter of the proximal end of the implement is equal to an overall diameter of the shaft so that a catheter having an inner diameter substantially equal to the overall diameter of the shaft may be passed over the proximal end of the implement and onto the shaft.
2. A surgical implement according to claim 1, wherein the domed distal end comprises a surface of revolution defined by an open curve.
3. A surgical implement according to claim 2, wherein said open curve is a parabola, a hyperbola or is semi-circular.
4- A surgical implement according to any preceding claim, wherein the lateral wall of the shaft is cylindrical.
5. A surgical implement according to any of claims 2 YO 4, wherein the domed distal end is provided as an insert for insertion into a distal end of the lateral wall.
6. A surgical implement according to claim 5, wherein the insert comprises a first cylindrical section providing a first cylindrical surface of the insert that intersects the surface of revolution; and wherein the diameter of the surface of revolution is equal to the diameter of the first cylindrical surface where the two surfaces intersect.
7. A surgical implement according to claim 6, wherein ends of the open curve that defines the surface of revolution comprise parallel tangents.
8. A surgical implement according to claim 6 or claim 7, wherein the domed distal end further comprises a second cylindrical section having an overall diameter that is less than an overall diameter of the first cylindrical section, the second cylindrical -9 -section extending concentrically from the first cylindrical section opposite the surface of revolution.
9- A surgical implement according to claim 8, wherein the lateral wall of the shaft is tubular and comprises an internal diameter; and wherein the overall diameter of the second cylindrical section is substantially equal to the internal diameter of the lateral wall, the second cylindrical being received within a distal end of the lateral wall and retained therein by interference fit.
10. A surgical implement according to claim 9, wherein lateral wall of the shaft abuts the first cylindrical section of the domed distal end, the overall diameter of the lateral wall and the overall diameter of the first cylindrical section being substantially the same so as to form a smooth transition between the domed distal end and the lateral wall.
A surgical implement according to any preceding claim, wherein an outer surface of the lateral wall and an outer surface of the domed distal end together form an outermost surface of the implement.
12. A surgical implement according to any preceding claim, wherein the opening in the lateral wall of the shaft comprises two, opposing openings in the lateral wall either side a longitudinal axis of the shaft.
13. A surgical implement according to claim 6, wherein the domed distal end of the shaft comprises a ramp that connects a distal edge of the opening in the lateral wall with an internal surface of the lumen.
14. A surgical implement according to claim 13, wherein the ramp comprises a curve of constant radius.
15. A surgical implement according to claim 13 or claim 14, wherein a distal end of the shaft comprises a slot; and wherein the opening in the lateral wall is formed between an edge of the slot and an edge of the insert.