WO2006103408A1

WO2006103408A1 - Improved obturator

Info

Publication number: WO2006103408A1
Application number: PCT/GB2006/001118
Authority: WO
Inventors: Stephen J. Fletcher
Original assignee: Fletcher Stephen J
Priority date: 2005-03-29
Filing date: 2006-03-28
Publication date: 2006-10-05
Also published as: GB0506175D0

Abstract

An obturator (30) for inserting a tube or tube (20) instrument into a body is disclosed which allows the tube or tubular instrument to be more easily- inserted in to the body. In an operative position, the obturator forms an outwardly and rearwardly diverging path equal to or beyond an outer periphery of a tube through which the obturator is inserted. A first embodiment of the obturator comprises a plurality of moveable projections (31a, 31b, 31c) . A second embodiment of the obturator comprises a resiliently deformable portion (43) .

Description

IMPROVED OBTURATOR

The present invention relates to an obturator for inserting a tube or tubular instrument into a body and, in particular, but not exclusively, an obturator for inserting a tracheostomy tube into a trachea.

A tracheostomy tube is used to allow a patient to breathe, even when the patient has a blockage of the trachea. For example, when a patient has a blockage of the larynx or pharynx.

To insert a tracheostomy tube into a patient, an incision is made to the patient's trachea below the obstruction. A distal end of a tracheostomy tube is then inserted into the trachea through the incision. A proximal end of the tube remains outside of the patient's trachea, allowing communication of ambient air with the patient's lungs. In addition, a ventilator can be attached to the proximal end of the tube to allow the patient's breathing to be assisted. Further, a gaseous source, such as a source of anaesthetic gas, can also be connected to the proximal end of the tube to, for example, supply the patient with a desired gaseous mixture.

In order to assist the insertion of the tracheostomy tube, it is common for an obturator to be used. An obturator is used to provide a tapering protrusion from the distal end of the tracheal tube. The tapering end of the obturator can then be used to guide the distal end of the tracheostomy tube through the incision. An example of a known obturator is shown in Figure 1. Here, the obturator 10 is shown slightly protruding from the distal end of a tube 20.

The obturator 10 comprises a distal end 11 and a longitudinal shaft 12. In use, the distal end 11 of the obturator 10 is inserted into the proximal end of the tube (not shown) and slid down the tube 20 until the distal end 11 of the obturator 10 projects or protrudes from the distal end 21 of the tube 20. The protruding distal end 11 of the obturator 10 can then be used to guide the tube 20 into an incision made in a patient's body.

As can be seen from Figure 1, the distal end 21 of the tube 20 forms a shoulder around the distal end 11 of the obturator 10. The shoulder is generally perpendicular or opposed to the longitudinal axis of the obturator and tube assembly. The shoulder can hinder and lengthen the time taken to increase the time taken to insert the obturator by resisting insertion of the obturator into the incision. During insertion, respiration of the patient is impossible or severely reduced. Therefore, reducing the time taken to insert the obturator is important. Further, when being inserted into the patient's body, the shoulder existing at the distal end 21 of the tube 20 can cause the incision in the patient's body to tear or distort as the tube 20 enters . Such tearing can be painful for the patient and may lead to damage of the skin surround this incision or the trachea itself.

It is an aim of the present invention to provide an obturator which allows the insertion of a tube or tubular instrument into a body without tearing of an incision. It is an aim of the present invention to provide an obturator which more easily allows a tube or tubular instrument to be inserted into a body.

According to the present invention there is provided an apparatus, kit of parts and method as set forth in the appended claims . Preferred features of the invention will be apparent from the dependent claims, and the description which follows .

According to a first aspect of the present invention, there is provided an assembly comprising: a tube and an obturator which, in an operative position, projects beyond an end of the tube, the obturator being retractable through the tube and in which, in the operative position, the assembly forms an outwardly and rearwardly diverging path equal to or beyond an outer periphery of the tube.

According to a second aspect of the present invention, there is provided a kit of parts as defined in the claims appended hereto.

According to a third aspect of the present invention, there is provided a method of using an assembly comprising a tube and an obturator in which the obturator extends beyond the end of the tube with the assembly having an outwardly and rearwardly diverging path equal to or beyond the outer periphery of the tube comprising inserting the projecting obturator and the distal end of the tube into a body and retracting the obturator through the tube. According to another aspect of the present invention, there is provided an obturator which, in an operative position, projects beyond an end of the tube, the obturator being retractable through the tube and in which, in the operative position, the assembly forms an outwardly and rearwardly diverging path equal to or beyond an outer periphery of the tube.

According to another aspect of the present invention, there is provided an obturator comprising: a distal end region for, in use, protruding from a distal end of a tube; at least part of the distal end region being arranged, in use, to expand to a size greater than an interior periphery of the tube.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

Figure 1 is a schematic longitudinal cross section through a prior art obturator projecting from a distal end of a tube;

Figure 2 is a lateral cross section (A) and a longitudinal cross section (B) of a first preferred embodiment of an obturator of the present invention inserted in a tube;

Figure 3 is a lateral cross section (A) and a longitudinal cross section (B) of the first preferred embodiment of an obturator of the present invention partially protruding from the tube; and Figure 4 is a lateral cross section (A) and a longitudinal cross section (B) of the first preferred embodiment of an obturator of the present invention having a distal end expanded to a size greater than an inner periphery of the tube;

Figure 5 is a lateral cross section of a second preferred embodiment of an obturator of the present invention inserted in a tube;

Figure 6 is a lateral cross section of the second preferred embodiment having a distal end expanded to a size greater than an inner periphery of the tube.

In the context of the present invention, it will be realised that the term obturator is taken to mean a device for inserting a generally tubular object or instrument into a body.

As shown in Figures 2A and 2B, a first preferred embodiment of an obturator 30 of the present invention is shown inserted in a tube 20. The first preferred embodiment 30 comprises a plurality of projections 31a, 31b and 31c extending in a distal direction. The projections meet a tubular part of the obturator 30 at the periphery 37. Whilst the obturator 30 is shown having three projections, it would be realised by a person skilled in the art that embodiments of the present invention may be envisaged having one, two, three, or more than three projections. When the first preferred embodiment 30 of the present invention is inserted into the tube 20, the projections 31a, 31b and 31c are arranged in an inwardly collapsed state so as to fit inside the interior of the tube 20. In the collapsed state, the projections 31a, 31b, 31c of the obturator 30 abut to have a generally circular lateral cross section, as can be seen from Figure 2A.

In the collapsed state, the projections 31a, 31b, 31c have an outer size less than an interior periphery of the tube 20. In this way, the obturator 30 can be inserted into the proximal end of the tube 20 and easily slid down the tube 20, until protruding from the distal end 21 of the tube 20 in an operative position.

The obturator 30 further comprises a longitudinally moveable member 32 which allows a user to assist in exerting an outward expanding force on the projections 31a, 31b, 31c, as will be explained later.

As shown in Figures 2A and 2B, once the obturator 30 is inserted into a tube 20, an elastic resilient force of the projections 31a, 31b, 31c may bring an outer surface 36a, 3βb, 3βc of each projection 31a, 31b, 31c into contact with and biased against an interior of the tube 20. In alternative embodiments, the projections 31a, 31b, 31c may be arranged to rest inward in a collapsed configuration, or may rest neutrally having no resilience toward the collapsed or expanded configurations. Such inward or neutral resilience may aid removal of the obturator 30. In Figures 3 and 4, like parts have the same reference numerals as in Figure 2. However, these are not shown to aid the clarity of the drawings.

As shown in Figure 2B, the distal tips of the projections 31a, 31b, 31c meet at a point region and their adjacent surfaces rearwardly from the point region contact with each other, thus defining a rearwardly, outwardly tapering, and effectively continuous surface. When the projections are between the positions shown in Figures 2B and 3B, the projections 31a, 31b, 31c are still held together by abutment of the outer surfaces 36a, 3βb, 36c of the projections against the internal wall of the tube 20.

In a first method of insertion, both the tube 20 and the obturator 30 can be advanced whilst the projections are generally in the collapsed state, such that the tips of the projections 31a, 31b, 31c enter the incision and urge the skin and tissues gently and evenly apart as advancement continues. For instance, by half the extent of the tapered portion of the projections 31a, 31b, 31c.

Then, as shown in Figures 3A and 3B, the plurality of projections 31a, 31b, 31c are further advanced to protrude from the distal end 21 and the resilience of each projection 31a, 31b, 31c causes the distal end region of the obturator 30 to expand to outwardly with the surfaces

36a, 36b, 36c extending a distance greater than that of an inner periphery of the tube 20. In other words, once protruding from the distal end 21 of the tube 20, the outer surfaces 36a, 36b, 36c are no longer restrained or contained by an interior of the tube 20. Once sufficiently advanced, each projection 31a, 31b, 31c is caused to move outward, thereby expanding at least part of the distal end region of the obturator 30 to a size greater than an interior size or periphery of the tube 20.

The resilient force is due to the elasticity or flexibility of a material used to form each projection 31a, 31b, 31c. Such resilience causes each projection 31a, 31b, 31c to outwardly separate from the inwardly collapsed position, expanding the distal end region of the obturator 30.

Further, the projections 31a, 31b, 31c may expand outward the distal end region of the obturator 30 such that the surfaces 36a, 36b, 36c extend to a size substantially equal to or greater than the outer periphery of the tube 20. Further, expansion may continue such that the surfaces 36a, 36, 36c extend to a size greater than the outer periphery so as to urge the incision apart to a size greater than that of the tube 20.

In addition to the outwardly expanding resilient force of each projection 31a, 31b, 31c, or alternatively thereto, the projections 31a, 31b, 31c may be moved outward by user induced movement of the longitudinally moveable member 32 relative to the tube 20. In this way, a user can exert an expanding force on the distal end region of the obturator 30 from the proximal end of the tube, outside the patients' body. Such force can be used in the first method of insertion to urge the incision further apart in a gentle manner, thus allowing further advancement of the obturator 30 and tube 20 into the patient's body. In the first preferred embodiment of the present invention, the moveable member 32 comprises an elongate shaft 32a, which is arranged to run in a longitudinal axis through the obturator 30. At a distal end of the shaft 32a, the member 32 comprises an enlarged plunger 32b, which is arranged to contact and move outward the projections 31a, 31b, 31c. In use, the user applies a force to a proximal end of the shaft 32a and moves the plunger 32 in a longitudinal direction toward or away from the distal end of the obturator 30, relative to the tip of each projection 31a, 31b, 31c.

When the user moves the plunger 32 toward the distal end, the rounded end 32b of the plunger 32 contacts and moves the projections 31a, 31b, 31c outward.

The plunger 32b has sides arranged to be substantially parallel to the inner periphery of the tube 20 and the plunger sides contact an interior surface of each projection 31a, 31b, 31c.

When the plunger 32b is moved from a retracted position, as shown in Figure 3B, to a forward position, as shown in Figure 4B, the plunger 32b contacts the inner surface of each projection 31a, 31b, 31c, thereby forcing the projections 31a, 31b, 31c outward and expanding the distal end region of the obturator 30. The plunger 32b causes each projection 31a, 31b, 31c to move outward until the inner surfaces of the projections are substantially parallel to the inner periphery of the tube 20. As shown in Figures 4A and 4B, the outer part of the projections that are coextensive with the tube are held against the inner surface of the tube 20. Thus in Figure 4, the obturator 30 and plunger 32b form a relatively rigid structure. The plunger 32b prevents inward movement of the projections 31a, 31b, 31c when in the forward position. A first stop (not shown) may be provided to prevent excessive forward movement of the plunger 32b, such a stop may be provided within the obturator body or upon the plunger 32b.

In the forward position, as shown in Figures 4A and 4B, the distal end of the plunger 32b forms a distal face of the obturator 30. In the first preferred embodiment, the distal face of the plunger end 32b has a concave profile or has a generally outwardly pointing or tapering profile. Thus, as shown in Figure 4B, when the obturator is located in the operative position having the plunger 32b moved forward, a rearwardly and outwardly diverging path is formed from a distal tip of the obturator 30 to the outer periphery of the tube 20. Advantageously, the rearwardly and outwardly diverging path reduces tearing of an incision during use and facilitates insertion.

In a second method of insertion, the already expanded obturator 30 protruding from the end of the tube 20 is inserted into the incision. The obturator 30 and tube 20 are then urged into the patient's body as a single assembly. Advantageously, the tapering profile of the assembly allows easy insertion of the obturator 30 and tube 20 into the incision. Since the expanded projections 31a, 31b, 31c accommodate the distal face of the tube 20, insertion into the patient's body is not restricted since the assembly of the tube 20 and obturator 30 forms an outwardly and rearwardly diverging path from the distal tip of the expanded obturator 30 to the outer surface of the tube 20. In embodiments of the present invention, part of the distal face of the tube and the outer surface of the tube 20 may form part of said path.

As can further be seen from Figures 4A and B, the outer surface of each projection 36a, 36b, 36c is arranged to engage with the distal end 21 of the tube 20. Advantageously, when the distal end region of the obturator 30 has expanded outward, the distal end 21 of the tube 20 is at least partially accommodated by the distal end region of the obturator 30. As shown in Figure 4A, looking through a lateral cross section of the obturator's 30 distal end region, the outer surface of the projections 36a, 36b, 36c are greater in size than an inner periphery of the tube 20. In this way, when the tube is inserted into a patient, tearing of the incision is lessened or eliminated and insertion is facilitated since the visible lateral cross section of the tube end 21 is reduced.

In the first preferred embodiment, the outer surface of each projection 31a, 31b, 31c has a shoulder 33a, 33b, 33c to accommodate the distal end of the tube 20 when the projections 31a, 31b, 31c have been moved outward. The shoulder 33 has a convex inner surface, which extends distally and outwardly, thereby aiding removal of the obturator 30 from the tube 20 as will be explained later. Further, the outer surface 34a, 34b, 34c of each projection 31a, 31b, 31c has a concave profile, wherein a tip of each projection has a minimum thickness and the shoulder 33 has a maximum thickness, thus extending distally and inwardly. In this way, when in the expanded state with the plunger 32b located forward, forming the distal face of the obturator 30, the distal end of the obturator 30 generally narrows or tapers inward toward the distal face.

The obturator 30 may further comprise a passageway running along the longitudinal axis of the obturator. Typically a guidewire, for example of l-2mm in diameter is inserted through the longitudinal passageway to run axially through the obturator 30 and the obturator 30 slid onto the guidewire. The guidewire is then inserted into the trachea at the start of the insertion procedure. The obturator 30 is then slid along the guidewire into the incision before being fully inserted in the previously explained manner.

When a tube 20 has been inserted into the patient, particularly when the tube is a tracheostomy tube, fast removal of the obturator 30 from the tube 20 is important. With the obturator 30 positioned in the tube 20, air is generally prevented from passing freely down the tube 20. Therefore, in the case of a tracheostomy tube, the obturator 30, must be quickly removed to allow the patient to breathe .

In the first preferred embodiment, the user applies a force to the shaft 32a in a proximal direction, thereby retracting the member 32 from the distal end of the obturator. Such force causes the member 32 to move in a proximal direction until the inward face of the plunger 32b abuts a second stop 35 and is located in the retracted position, as shown in Figure 3B. Continued application of a force in the proximal direction to the obturator 30 or shaft 32a causes the projections 31a, 31b, 31c to move inward since the shoulder 33 of each projection 31a, 31b, 31c contacts the distal end of the tube 20. Thus the proximal retracting force acting on the obturator causes an inward collapsing force to act on each projection 31a, 31b, 31c. Due to the outwardly tapering inner surface of each shoulder 33, the retracting proximal force collapses the projections 31a, 31b, 31c inward until an outer surface 36a, 36b, 36c of each projection 31a, 31b, 31c contacts the inner surface of the tube 20. Once each projection 31a, 31b, 31c has been moved inward, the obturator 30 can be slid in a proximal direction along the tube 20 and safely removed.

In a second preferred embodiment, an obturator 40 comprises a tubular body and a moveable member as in the first preferred embodiment.

A distal end region of the obturator comprises a rearwardly and outwardly diverging angled portion 41 surrounding an opening 42. A resiliently deformable portion 43 is arranged between the angled portion 41 and a tubular body 44 of the obturator 40. The resiliently deformable portion 43 of the obturator 40 is formed from an elastic material, for example, silicone rubber, to have, in the collapsed state or inserted position, a generally laterally cylindrical, continuous profile. The mid-section of the resiliently deformable portion 43 has a minimum diameter with outwardly tapering sections either side. However, embodiments having a cylindrical, outwardly or other profile may be envisaged which fit into the tube 20. Longitudinally, in the inserted position, the obturator's 40 distal end region generally tapers inwardly toward the distal tip and opening 42. Once the obturator 40 is advanced to project from a distal end of a tube 20, a moveable member 45 arranged within the obturator 40 can be moved forward within the obturator 40 to cause the distal end region, in particular although not exclusively, the resiliently deformable portion 43, to elastically expand outward in order to internally accommodate the moveable member 45. Such outward expansion causes the distal end region of the obturator 40 to expand to a size greater than an interior periphery of the tube 20.

As shown in Figure 6, the distal end region of the moveable member 45 is arranged to have an outwardly tapering profile when in an operative or expanded state. In the second preferred embodiment, the distal end region of the moveable member 45 has an outwardly and readwardly diverging conical profile. The angled portion 41 diverges with the same angle as the conical tip of the moveable member. In this way, when the obturator 40 is arranged in the operative position with the distal end protruding from the tube 20 and the resiliently deformable portion 43 in an expanded state, the moveable member 45 and angled portion 41 cooperate to form a substantially continuous, outwardly and rearwardly diverging, effectively continuous surface. The outer surface diverges beyond an inner periphery of the tube 20 to, or beyond, an outer periphery tube 20.

The moveable member 45 of the obturator 40 operates in a the same manner as the first preferred embodiment and has the same structure, unless otherwise described. The second embodiment of the obturator 40 comprises an interior channel, within which the moveable member 45 slides. The interior of the channel may comprise an inwardly diverging profile, arranged forward of the moveable member 45 when said member 45 is arranged in a rearward, or retracted, position. In this way, when the moveable member 45 is actuated toward the distal tip of the obturator 40, the inwardly diverging profile of the channel causes outward deformation or expansion of the obturator's 40 external surface, so as to expand the distal end region of the obturator 40, as shown in Figure 6.

Once inserted into a patient, the moveable member 45 can be moved rearwardly to cause the resiliently deformable portion 43 to contract back to its original size and shape, or approximately thereto, to facilitate removal of the obturator 40 from the tube 20.

Embodiments of the obturator 30, 40 are resiliently bendable so as to allow for being inserted down a curved tube such as a tracheostomy tube. The obturator 30, 40 may be made from nylon or other suitable material.

The obturator 30, 40 may be re-used numerous times as required by the user. It will be realised that the usefulness of the present invention is not limited to the insertion of tracheostomy tubes. Instead, any type of generally tubular article or tubular instrument may be inserted using the present invention. Further, the present invention may be supplied as an assembly having an obturator 30, 40 located in the operative position within a tube 20 ready for use. As explained above, the present invention provides an obturator which allows this insertion of a tube into a body which reduces the tearing or distortion of an incision through which the tube is being inserted.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features .

The invention is not restricted to the details of the foregoing embodiment (s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. An assembly comprising:

a tube (20) and an obturator (30) which, in an operative position, projects beyond an end of the tube (20) , the obturator (30) being retractable through the tube (20) and in which, in the operative position, the assembly forms an outwardly and rearwardly diverging path equal to or beyond an outer periphery of the tube (20) .

2. The assembly as claimed in claim 1 in which the path diverges along its complete length from the end of the assembly to the end of the tube (20) .

3. The assembly, according to claim 1 or 2, wherein the outwardly and rearwardly diverging path is a generally curved path.

4. The assembly, according to claim 1, 2 or 3, wherein at least part of the tube (20) forms at least part of the path.

5. The assembly, according to claim 4, wherein at least part of the distal end face (21) of the tube (20) forms at least part of the path.

6. The assembly, according to any of claims 1 to 5, wherein at least part of a distal end region of the obturator (30) forms at least part of the path.

7. The assembly, according to any of claims 1 to 6, wherein: at least part of the distal end region of the obturator (30) being arranged, in the operative position, to expand to a size greater than an interior periphery of the tube (20) .

8. The assembly according to any preceding claim, wherein:

at least part of the dis±al end region of the obturator (30) being arranged, in the operative position, to expand to a size substantially equal to an outer periphery of the tube (20) .

9. The assembly according to any preceding claim, wherein :

at least part of the distal end region of the obturator (30) being arranged, in the operative position, to expand to a size greater than the outer periphery of the tube (20) .

10. The assembly according to any preceding claim, the distal end region of the obturator (30) comprising:

at least one projection (31a, 31b, 31c) , wherein an end region (34a, 34b, 34c) of each projection (32) is moveable outward to expand the distal end region of the obturator (30) .

11. The assembly according to claim 10, wherein: the end region (34a, 34b, 34c) of each projection (32) is moveable outward by a resilient elastic force of the projection (32) .

12. The assembly according to claim 10 or 11, wherein:

the end region (34a, 34b, 34c) of each projection (32) being moveable outward by an expanding force exerted by a user .

13. The assembly according to claim 10, 11 or 12, the obturator (30) comprising:

a means for moving each projection (32) outward, so as to expand the distal end region of the obturator (30) .

14. The assembly according to claim 13, wherein:

the means for moving each projection (32) outward includes an inner member (32) of the obturator (30), the inner member (32) being movable by a user.

15. The assembly according to claim 13 or 14, wherein:

the means for moving each projection (32) outward includes a resilient force of the at least one projection (31a, 31b, 31c) .

16. The assembly according to claim 14 or 15, wherein:

the inner member (32) is moveable in a direction towards the tip of the at least one projection (31a, 31b, 31c) to form a distal end region of the obturator (30) .

17. The assembly according to claim 16, wherein:

the inner member (32) is moveable between a forward position, wherein the moveable member forms the distal face of the obturator (30) , and a retracted position, wherein the end region (34a, 34b, 34c) of each projection (32) is moveable inward to a collapsed state.

18. The assembly according to claim 17, wherein:

the inner member (32), in the forward position, assists in preventing inward movement of the projections.

19. The assembly according to claim 17 or 18, wherein:

the inner member (32), in the forward position, assists in holding those parts of the projections that are coextensive with the tube (20) against the inner surface of the tube.

20. The assembly according to claim 17, 18 or 19, wherein:

the inner member (32) , in the forward position, and the at least one projection (31a, 31b, 31c) form a relatively rigid structure.

21. The assembly according to any of claims 14 to 20, wherein: the inner member (32) is longitudinally moveable by the user relative to the tube (20) .

22. The assembly according to any of claims 17 to 21, the inner member (32) comprising:

a shaft (32a) arranged longitudinally through the obturator (30) ;

an end portion (32b) arranged at a distal end of the shaft (32a) .

23. The assembly according to claim 22, wherein the end portion (32b) of the inner member (32) includes substantially parallel outer sides.

24. The assembly according to claim 23, wherein the outer sides of the inner member (32) cooperate with an inner surface of the at least one projection (31a, 31b, 31c) .

25. The assembly according to claim 23 or 24, wherein the outer sides of the inner member (32) cooperate with an inner surface of the at least one projection (31a, 31b, 31c) to move said projection (32) outward.

26. The assembly according to claim 23, 24 or 25 wherein the parallel outer sides of the inner member (32) comprises a cylindrical surface.

27. The assembly according to any of claims 22 to 26, wherein the end portion (32b) of the inner member (32) has a rearwardly and outwardly tapering end.

28. The assembly according to any of claims 22 to 27, wherein:

a proximal end of the shaft (32a) cooperates with a means for moving the inner member (32) between the forward and retracted positions.

29. The assembly according to any of claims 14 to 28, wherein the inner member (32) is a plunger.

30. The assembly according to any of claims 17 to 29, wherein:

in the retracted position the inner member (32) abuts a stop.

31. The assembly according to any of claims 10 to 30, wherein :

the end region (34a, 34b, 34c) of each projection (32) has a generally curved or convex outer surface .

32. The assembly according to any of claims 10 to 31, wherein:

the end region (34a, 34b, 34c) of each projection (32) has an inwardly tapering outer profile.

33. The assembly according to any of claims 10 to 32, wherein: each projection (32) has a generally curved lateral cross section.

34. The assembly according to any of claims 10 to 33, wherein:

each projection (32) has an engagement portion (33a, 33b, 33c) for, in use, engaging with the distal end face (21) of the tube (20) .

35. The assembly according to claim 34, wherein:

the engagement portion (33a, 33b, 33c) is a generally outwardly curved protrusion with the curve extending distally and inwardly.

36. The assembly according to claim 35, wherein:

the distal end face (21) of the tube (20) and the protrusion are arranged to cooperate with each other, such that relative movement of the obturator (30) in the proximal direction with respect to the tube (20) is arranged to cause inward movement of the projection (32) with respect to the tube (20) .

37. The assembly according to claim 34, 35 or 36, wherein:

the engagement portion (33a, 33b, 33c) is a shoulder having a generally convex longitudinal cross section.

38. The assembly according to any of claims 34 to 37, wherein: the engagement portion (33a, 33b, 33c) has a profile suitable for at least partially accommodating the distal end of the tube.

39. The assembly according to any of claims 16 to 38, the obturator (30) comprising a plurality of projections (31a, 31b, 31c) .

40. The assembly according to claim 39, the obturator (30) comprising three projections (31a, 31b, 31c) .

41. The assembly according to claim 39 or 40, wherein:

the plurality of projections (31a, 31b, 31c) can be arranged, in use, in a collapsed state.

42. The assembly according to claim 41, wherein:

in the collapsed state, the plurality of projections (31a, 31b, 31c) have an outer size of less than an interior periphery of the tube (20) .

43. The assembly according to claim 41 or 42, wherein:

in the collapsed state, the plurality of projections (31a, 31b, 31c) abut to have a generally circular cross section.

44. The assembly according to claim 43, wherein the generally circular cross-section tapers rearwardly and outwardly.

45. The assembly according to claim 41, 42, 43 or 44, wherein:

in the collapsed state an outer region of each obturator (30) projection (31a, 31b, 31c) abuts the inner face of the tube (20) .

46. The assembly according to claim 45, wherein:

in the collapsed state the outer region of each projection abuts an inner face of the tube (20) to assist in holding the plurality of projections in abutment.

47. The assembly according to any of claims 14 to 46, wherein:

the at least one projection (31a, 31b, 31c) and the inner member (32) cooperate to form a tapering protrusion from the distal end of the tube (20) .

48. The assembly according to any of claims 1 to 9, the distal end region of the obturator (30) comprising a resiliently deformable portion (43) for expanding outward to form an outwardly and rearwardly diverging path equal to or beyond an outer periphery of the tube (20) .

49. The assembly according to claim 48, wherein the resiliently deformable portion (43) is caused to outwardly expand by a force exerted by a user.

50. The assembly according to claim 49, the obturator (30) comprising an inner member (45) , longitudinally moveable by a user to outwardly expand the distal end region of the obturator (30) .

51. The assembly according to claim 50, wherein, in use, the inner member (45) contacts an inner surface of the resiliently deformable portion (43) , thereby outwardly expanding the distal end region of the obturator (30) .

52. The assembly according to any of claims 48 to 51, wherein the resiliently deformable portion (43) is silicone rubber.

53. The assembly according to any of claims 48 to 51, wherein the obturator (30) comprises an outwardly tapering portion (41) at the distal end region of the obturator (30) .

54. The assembly according to any of claim 53, wherein the outwardly tapering portion (41) is arranged between the resiliently deformable portion (43) and the distal tip of the obturator (30) .

55. The assembly according to any of claims 48 to 54, wherein the distal tip of the obturator (30) comprises an aperture (42) .

56. The assembly according to any of claims 48 to 55, the obturator (30) comprising a means for outwardly expanding (45) the resiliently deformable portion (43) .

57. The assembly according to claim 56, wherein: the means for outwardly expanding (45) the resiliently deformable portion (43) includes an inner member (45) of the obturator (30), the inner member (45) being movable by a user.

58. The assembly according to claim 57, wherein:

the inner member (45) is moveable in a direction towards the tip of the obturator (30) to form a distal end region of the obturator (30) .

59. The assembly according to claim 58, wherein:

the inner member (45) is moveable between a forward position, wherein the moveable member forms the distal face of the obturator (30) , and a retracted position, wherein the resiliently deformable portion (43) is suitable to enter the tube (20) .

60. The assembly according to claim 59, wherein:

the inner member (45) , in the forward position, assists in preventing inward deformation of the resiliently deformable portion (43).

61. The assembly according to claim 59 or 60, wherein:

the inner member (45), in the forward position, assists in holding a region of the resiliently deformable portion (43) against an interior of the tube (20) .

62. The assembly according to claim 59, 60 or 61, wherein: the inner member (45) , in the forward position, and the resiliently deformable portion (43) form a relatively rigid structure.

63. The assembly according to any of claims 57 to 62, wherein:

the inner member (45) is longitudinally moveable by the user relative to the tube (20) .

64. The assembly according to any of claims 57 to 63, the inner member (45) comprising:

a shaft (32a) arranged longitudinally through the obturator (30);

an end portion (32b) arranged at a distal end of the shaft (32a) .

65. The assembly according to claim 64, wherein the end portion (32b) of the inner member (45) includes substantially parallel outer sides.

66. The assembly according to claim 65, wherein the outer sides of the inner member (45) cooperate with an inner surface of the obturator (30) .

67. The assembly according to claim 65 or 66, wherein the outer sides of the inner member (45) cooperate with an inner surface of an axial channel in the distal end region of the obturator (30) .

68. The assembly according to claim 65, 66 or 67 wherein the parallel outer sides of the inner member (45) comprises a cylindrical surface.

69. The assembly according to any of claims 64 to 68, wherein the end portion (32b) of the inner member (45) has a rearwardly and outwardly tapering end.

70. The assembly according to any of claims 64 to 69, wherein:

a proximal end of the shaft (32a) cooperates with a means for moving the inner member (45) between the forward and retracted positions.

71. The assembly according to any of claims 57 to 70, wherein the inner member (45) is a plunger.

72. The assembly according to any of claims 57 to 71, wherein:

in the retracted position the inner member (45) abuts a stop.

73. The assembly according to any preceding claim, wherein the obturator (30) is resiliently flexible.

74. The assembly according to any preceding claim, the obturator (30) being suitable for use with a tracheostomy tube (20) .

75. The assembly according to any preceding claim, wherein the tube (20) is a tracheostomy tube.

76. The assembly according to any preceding claim, wherein the obturator (30) comprises a longitudinal channel for allowing a guidewire to pass therethrough.

77. An obturator (30) according to any preceding claim.

78. A kit of parts comprising:

the obturator (30) according to any of claims 1 to 76; and

a tube (20) .

79. The kit of parts according to claim 78, wherein the tube (20) is a tracheostomy tube.

80. A method of using an assembly comprising a tube (20) and an obturator (30) in which the obturator (30) extends beyond the end of the tube (20) with the assembly having an outwardly and rearwardly diverging path equal to or beyond the outer periphery of the tube (20) comprising inserting the projecting obturator (30) and the distal end of the tube (20) into a body and retracting the obturator (30) through the tube (20) .

81. The method of using an assembly according to claim 80, comprising:

moving an inner member (32,45) of the obturator (30) so as to assist in retracting the distal end region of the obturator (30) protruding from the tube (20) .

82. The method of using an assembly according to claim 80 or 81, comprising:

causing a protruding part of the obturator (30) to engage with the end of the tube (20) to assist in causing contraction of the distal end region of the obturator (30) .

83. The method of using an assembly according to claim 80, 81 or 82, comprising:

moving an inner member of the obturator (30) so as to assist in expanding the distal end region of the obturator (30) .

84. The method of using an assembly according to any of claims 81, 82 or 83, comprising:

causing the inner member of the obturator (30) to assist in holding the protruding end in an expanded position .

85. The method of using an assembly according to any of claims 81 to 84, comprising:

causing the inner member of the obturator (30) to assist in expanding the distal end region of the obturator (30) by moving outward at least one projection (31a, 31b, 31c) .

86. The method of using an assembly according to claim 85, comprising: causing the inner member of the obturator (30) to assist in holding the at least one projection

(31a, 31b, 31c) against the inner wall of the tube (20) when the distal end region is located at least partly within the tube (20) .

87. The method of using an assembly according to any of claims 81 to 84, comprising:

causing the inner member of the obturator (30) to assist in expanding the distal end region of the obturator (30) by expanding outward a resiliently deformable portion (43) of the obturator (30) .

88. The method of using an assembly according to any of claims 81 to 87, comprising:

moving the inner member toward a distal end of the obturator (30) so as to expand the distal end region of the obturator (30) .

89. The method of using an assembly according to any of claims 81 to 88, comprising:

moving the inner member toward a proximal end of the obturator (30) so as to assist in retracting the obturator (30) .

90. The method of using an assembly according to any of claims 80 to 89, comprising:

inserting the obturator (30) into the tube (20) .

91. The method of using an assembly according to any of claims 80 to 90, comprising:

inserting the expanded distal end region of the obturator (30) into a body.

92. The method of using an assembly according to any of claims 80 to 91, comprising:

removing the obturator (30) from the tube (20) .

93. The method of using an assembly according to any of the claims 80 to 92 comprising:

inserting a guidewire through the obturator (30) .