WO2005082446A1

WO2005082446A1 - Inflatable balloon device for application in surgery or in pipelines

Info

Publication number: WO2005082446A1
Application number: PCT/GB2005/000691
Authority: WO
Inventors: Richard Michael Bestall Halpin; David Kenneth Oram; Martin Ian Gordon
Original assignee: Halpin Innovation Limited
Priority date: 2004-02-25
Filing date: 2005-02-24
Publication date: 2005-09-09
Also published as: GB2439401A; GB2439401B; GB0617489D0; GB0404130D0

Abstract

An inflatable device (1) for inserting, in a deflated state, into a tubular duct such as, for example, a blood vessel (26) in a human or animal. The device has an inflated state in which it defines an elongate open-ended tube having an outer surface formed and arranged to fit closely to the interior surface of the tubular duct, whereby, in its inflated state, fluid or other matter carried by the duct passes through the tube. The tube has collapsible walls defining an inflatable pipe which is bent back on itself at a plurality of locations to form a multiplicity of parallel pipe segments 10-17 extending substantially parallel to an axis of the tube. The device can alternatively be designed for use in industrial pipelines (7), for example to facilitate repair of a damaged portion of the pipeline while allowing fluid to continue to flow through the pipeline.

Description

INFLATABLE BALLOON DEVICE FOR APPLICATION IN SURGERY OR IN PIPELINES The present invention relates to inflatable balloon devices for use in surgery or for use in fluid-conveying pipelines such as, for example, oil and gas pipelines, and sewage and water pipelines. In particular, though not exclusively, the invention relates to devices for controlling extra vascular haemorrhage and an inflatable device for use as an intravascular haemostatic device. Damage or injury to blood vessels may lead to extravasation (bleeding out from blood vessels) . Such internal bleeding leads, in turn, to loss of blood-pressure in the patient having the damaged or injured blood vessel. Extravasation is particularly dangerous to the patient where the damaged vessels are the retro-hepatic vena cava, the inferior vena cava and/or the hepatic veins as these blood vessels are very difficult to reach by a surgeon for repair thereof. These blood vessels are located close to the spine and behind the liver, and for a surgeon to repair a damaged vessel of this type it is first necessary for the surgeon to be able to have relatively unhindered access to the vessel. Usually, access to damaged blood vessels may be achieved by relatively straightforward dissection. However, in the case of damage to the retro-hepatic vena cava or the hepatic veins the emergency dissection required is particularly difficult as the surgeon must generally dissect anteriorly with the bulk of the liver directly in the way with the result that access is obstructed. This is very time consuming. Procedures to repair damaged blood vessels must in general be performed as quickly as possible to minimise the degree of extravasation. Control of extravasation must be achieved at the earliest opportunity i.e. within a matter of a few minutes at most, especially where a major blood vessel is damaged. It is possible for total exsanguination (i.e. not enough blood remains to sustain life) to occur within two or three minutes. Injury or damage to the liver itself, particularly where there is severe disruption to the liver architecture by penetrating injury, avulsion of the liver, or maceration of the liver itself resulting in loss of integrity of the liver's own blood vessels, and thus haemorrhage, is associated with high mortality and morbidity. Difficulty in achieving timely control of extravasation results generally in blood flowing back along the hepatic veins and out through the damaged/injured liver and into the peritoneum. The difficulty in controlling extravasation is inter alia a direct result of the difficulty of the surgeon gaining quick access to the injury site and then establishing control of the extravasation. It is also difficult to both operate and control haemorrhage at the same time. Once a surgeon has gained access to the injured or damaged vessel or organ, in order to repair the damaged portion thereof, it is necessary to at least temporarily control the extravasation from the injury or damaged portion of the vessel or organ. This at least temporary control of extravasation allows the surgeon to effect a repair to the injured/damaged vessel or organ. In techniques where such temporary control is imposed, the organs or other body part(s) supplied by blood from the damaged vessel (or for blood returning to the heart) may be starved of blood (ischaemia) . This can have serious consequences such as organ damage, or mortality. Temporary control of extravasation from the damaged/injured vessel/organ must therefore not substantially prevent blood flow to or from another organ or body part to be supplied therefrom, if these serious complications are to be avoided. WO 01/47594 Al, having one inventor in common with the current application, describes an inflatable device for insertion, in a substantially deflated state, into a blood or other biological fluid carrying vessel. By positioning the device at or near the site of the damaged portion of the vessel and then inflating the device (with saline or another suitable fluid) extra-vascular haemorrhage from the damaged portion is controlled. In its inflated state the device defines an elongate open-ended tube having a passage extending therethrough which allows the blood to flow through the device while the surgeon repairs the damaged portion of the vessel. One problem associated with this device is that it is difficult to control the removal of the inflating fluid from the device so that it deflates fully. For example, as the saline or other inflating fluid is drawn out of the device the collapsible walls of the inflatable device may collapse in on themselves so that, for example, one end of the device is deflated while the other end remains inflated. This problem is hereinafter referred to as the "differential collapse" problem. Another potential problem is that the inflatable volume defined between the collapsible inner and outer walls of the tube may tend to expand both radially outwardly and radially inwardly when the tube is being inflated, thereby decreasing the size of the blood flow passage through the device as the device is inflated more and more. Thus if the device is over inflated it may begin to restrict blood flow therethrough. It is an object of the present invention to avoid or minimise one or more of the foregoing disadvantages. According to a first aspect of the present invention there is provided an inflatable device for inserting, in a substantially deflated state, into a tubular duct, the device having an inflated state in which it defines an elongate open-ended tube having an inlet end and an outlet end, said tube having an outer surface formed and arranged to fit, in said inflated state of the device, closely to the interior surface of the tubular duct in use of the device, whereby, in use of the device in its inflated state, fluid or other matter carried by the duct may pass through the tube via the inlet and outlet ends thereof , wherein said tube comprises collapsible walls defining an inflatable pipe which is bent back on itself at a plurality of locations to form a multiplicity of parallel pipe segments extending substantially parallel to an axis of said tube, the walls of adjacent pipe segments being bonded to one another so as to form said open-ended tube. One advantage of the invention is that when the device is inflated the pipe inflates but the axial passage through the open-ended tube formed from the pipe does not get smaller and smaller as the pipe is further and further inflated. In effect, the inflated device is better able to retain its tubular shape as it is increasingly inflated. The bonded together inflatable pipe sections effectively define inner and outer walls of the inflatable tube. These inner and outer walls are constrained from moving too far away from one another as the device is inflated, due to the pipe segments being bonded together. The invention is applicable not just in the surgical field, in which the device is designed for inserting into a vessel of a human or animal (such as a blood vessel) , but may be applied in any field in which repair of a pipeline may need to be carried out, for example in oil and/or gas pipelines, or sewage, water or other underground pipelines. In these other fields the invention offers the advantage that by positioning the device adjacent the damaged portion of the pipeline, repairs to the damaged portion can be carried out while fluid can continue to flow though the pipeline. It will therefore be appreciated that the size of the device, and the materials from which it is made, will depend on the intended application of the device. The method of manufacture of the device may also vary depending on the intended application of the device. In surgical applications the fluid used to inflate the device will normally be saline. In other applications other liquids or gases may be used such as, for example, water, air or C0₂ • Preferably, the device further includes an elongate object disposed inside the inflatable pipe, in the inflatable volume thereof, for substantially preventing differential collapse of the tube when the tube is being deflated. Where the device is designed for surgical application, the elongate object may, for example, comprise a length of thread running through the hollow interior of the inflatable pipe, preferably along the entire length of the inflatable pipe. The thread prevents opposing wall portions of the pipe from collapsing fully flat against one another as the tube is being deflated. If this happened at one or more locations in the pipe the saline (or other fluid used to inflate the device) could become trapped in one or more sections of the inflatable pipe, whereby the tube would not fully deflate. Instead of a length of thread, other objects could be disposed within the inflatable pipe to achieve a similar effect. For example one or more elongate plastic bodies having a plurality of radially extending lobes, for example an elongate body of generally clover-leaf or star-shaped end cross-sectional shape, could be used. Alternatively, the collapsible walls may themselves be configured so as to substantially prevent them from lying flat against one another when the device is deflated. As well as being suitable for use in blood vessels of the human or animal body, the invention is also suitable for applications in the lumina of other body vessels or organs such as, for example, the oesophagus or intestines, where it may sometimes be desirable to block a damaged portion of the vessel to allow fluids or other matter (e.g. digested food) to continue to pass through the vessel while it is being repaired. Other possible areas of application include the nasal cavity and the vagina. As aforementioned, it will be appreciated that the device must be manufactured to a size designed for its specific purpose e.g. smaller diameter tubes will be required for small blood vessels than for large blood vessels. It will also be appreciated that in addition to being ideally suited to be positioned at or close to the damaged portion of the vessel to be repaired, the device is also suited for applications where it may be desirable for the surgeon to block blood flow from a blood vessel into a particular organ which is damaged and which the surgeon is about to repair. For example, where the liver has been damaged in a trauma event, the surgeon may wish to keep the liver "dry" while the repair operation is performed and to this end the inventive device may conveniently be positioned in the inferior vena cava (this carries blood back to the heart) at the point where it receives the hepatic veins (the hepatic veins drain blood from the liver into the inferior vena cava) . This length of the inferior vena cava is referred to as the retro-hepatic vena cava - it lies behind the liver and is partly surrounded anteriorly by the liver. Inflating the balloon in the retro-hepatic vena cava has the effect that the balloon stops abnormal or retrograde blood flow from the inferior vena cava into the liver (such abnormal backflow may occur where the liver has lost the integrity of its architecture, or been torn off the hepatic veins, or where the liver and hepatic veins have been torn off the inferior vena cava (hepatic avulsion) , or if there has been penetrating trauma such as a knife or bullet wound at that site) , while still allowing normal blood flow in one direction (the correct direction, namely blood flow back to the heart) to continue in the inferior vena cava. It will be appreciated that where an operation is to be carried out on the liver which may cause temporary damage to the liver, it may be useful for the surgeon to insert the deflated balloon into the inferior vena cava (IVC) before surgery, so that it is ready to be blown up as soon as the operation starts. Preferably, where the device is intended for surgical application, the collapsible walls are formed from a material which is non-thro bogenic and non-allergic for humans (or animals, depending on the intended use of the device) . However, thrombogenic materials may alternatively be used as long as the device is heparin-bonded prior to use, to prevent blood clots forming on the device in use thereof. Conveniently, the collapsible walls of the device may be formed from a material which bonds to itself when subjected to a sufficiently high temperature and/or pressure such as, for example, polyolefin. This may facilitate manufacture of the device. However, the collapsible walls may alternatively be made of other materials which also exhibit this property, or any other physiologically compatible material which can be bonded to itself in a convenient manner, for example using adhesive. One end of the inflatable pipe may be sealed off and the other end may be attached to, and in fluid communication with, an inflation fluid delivery pipe via which saline (or other fluid) may be delivered to the hollow interior of the pipe to inflate the pipe, and thereby form the inflated tube. Alternatively, the inflatable device may be attached to a catheter via which saline or other fluid for inflating the device may be delivered to the device. The inflatable device may be provided with one, preferably two, input/output ports for attachment to the catheter, these input/output ports being in fluid communication with the hollow interior of the inflatable pipe. The catheter is preferably provided with a respective connection port, which may conveniently be in the form of a bifurcation, for each said input/output port, the connection port(s) being configured such that a saline (or other fluid) delivery channel in the catheter is in fluid communication with the hollow interior of the inflatable pipe when the input/output port(s) is/are connected thereto. Providing two input/output ports on the device may facilitate the filling/emptying of the inflatable device with inflation fluid. Preferably the input/ouput port(s) on the inflatable device are located on an inner surface of the open-ended tube, such that the catheter extends into or through the tube. Preferably, where two input/ouput ports are provided on the device these two ports are located proximal to opposite ends of the tube. This facilitates the use of the catheter to tow the device into or out of the body. According to another aspect of the invention there is provided a kit-of-parts comprising the inflatable device according to the first aspect of the invention for inserting into a tubular duct, and insertion means for facilitating access to the inside of said tubular duct. The kit-of-parts may include deployment means for deploying the device to its inflated state. According to another aspect of the invention there is provided a method of manufacturing an inflatable device for inserting, in a substantially deflated state, into a tubular duct such as, for example, a vessel of a human or animal, the method comprising the steps of: providing an open-ended inflatable pipe made of a material which bonds to itself when subjected to a sufficiently high temperature and/or pressure; sealing off one end of this pipe; providing an elongate baking tool comprising a cylinder having a plurality of winding pins arranged in two spaced apart sets of pins, each set comprising a plurality of pins extending radially outwardly from the cylinder and disposed around the circumference of the cylinder; winding the inflatable pipe, in its deflated state, around the winding pins provided on the baking tool so as to wind the pipe up and down along the length of the cylinder so as to form a multiplicity of substantially parallel pipe segments arranged in close relationship to one another around the full circumference of the cylinder; inflating the pipe under pressure and applying sufficient heat to the pressurised pipe that adjacent inflated pipe segments are bonded together, thereby forming an open-ended tube; releasing the bonded pipe from the winding pins of the baking tool. The method may further include threading a cotton thread through the inflatable pipe prior to sealing off said one end of the pipe. The method may also include attaching a saline (or other fluid) delivery tube to the other end of the inflatable pipe prior to winding the pipe onto the baking tool. The inflatable pipe may be made of heat shrink material and the pipe is preferably heat- stretched under pressure, most conveniently in a vertical oven, prior to winding it around the baking tool. Preferred embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings in which:

Fig.l is a side view of an inflatable device according to one embodiment of the invention, showing the device in its inflated state;

Fig.2 is an end view of the device of Fig.l; Fig.3 is a perspective view of the device of Figs.l and 2;

Fig.4 is an end cross-sectional view through the device of

Fig.l, showing a length of thread disposed within the device; Fig.5 is a schematic side view of the device of Figs.l to 4 assembled to a catheter;

Fig.6 is a side cross-sectional view, taken along the length of the catheter of Fig.5, showing a saline supply channel in the catheter; Figs.7 (a) to (n) illustrate consecutive stages in the manufacturing of the device of Figs. 1 to 3;

Fig.8 (a) is a schematic side view of the inflated device of

Fig.l to 4 positioned inside a damaged blood vessel;

Fig.8(b) is a schematic cross-sectional view of the inflated device of Figs.l to 4 inside the damaged blood vessel of Fig.8 (a), taken along the line A-A' in Fig.8 (a);

Fig.9 is a schematic side view of a modified version of the device of Fig.l;

Fig.10 is an end view of another modified version of the device of Fig.l; and

Fig.11 is a side view of a pipeline in which an inflatable device according to another embodiment of the invention is deployed. Figs. 1 to 3 illustrate an inflatable device for surgical use. The inflatable device 1 is shown in its inflated state in which it defines a generally tubular form having an inlet end 2 and an outlet end 3 and a hollow passage 4 defined therebetween and extending generally axially through the tubular form. The tubular form is itself made up of 8 pipe segments 10 to 17 each extending generally parallel to the axis of the tubular form and arranged in series, adjacent to one another, around an imaginary ring, such that the last segment 17 is adjacent to the first segment 10 The pipe segments 10 to 17 are also integrally connected in series via their opposite ends so that the hollow interiors of the pipe segments 10 to 17 are in fluid communication with one another, whereby the eight pipe segments together form a single inflatable pipe which may be inflated with saline or any other physiologically compatible fluid via an inflation fluid delivery pipe 20 connected to the free end 18 of the final pipe segment 17. The other end of the inflatable pipe is the free end of the first pipe segment 10, this end being sealed off so that the pipe inflates when saline is delivered from the delivery pipe 20 into the end 18 of the final pipe segment 17. Adjacent walls of adjacent ones of the pipe segments 10 to 17 are bonded permanently to one another (as will be described in detail later) so as to permanently define the tubular form of the device 1. As will be described in further detail later, the tubular shape is basically formed by bending a single elongate inflatable pipe back on itself several times (in this embodiment seven times) so as to form several U-shaped bends 8 at opposite ends of the device. It is these U-shaped bends which define the inlet and outlet ends of the generally tubular form, as can be seen clearly from figures 1 to 3. The inflatable pipe is made from a flexible plastics material, in this embodiment polyolefin. A cotton thread 20 extends through the hollow interior of the inflatable pipe, and thus extends back and forth between the inlet and outlet ends 2, 3 of the tubular form, inside the eight pipe segments 10 to 17, as illustrated in the cross sectional view of the device seen in Fig. 4. The device is designed to be inserted in its deflated state, into, for example, a blood vessel of a human or animal. When the deflated device has been positioned at a desired location in the vessel (for example so as to lie generally parallel with a damaged portion 25 of the vessel 26, or next to another vessel 25 branching from the main vessel 26. The device is inflated with saline so as to expand it to its fully inflated state see (Figs. 8(a) and (b) ) . The diameter of the generally tubular form of the device is pre-determined so that the outer surface of the inflated device will fit closely to the inner wall (ie intima) of the vessel, around the whole circumference of the intima. This has the effect that blood (or other biological fluid) in the vessel flows through the generally axial passage 4 of the inflated tubular device 1, from the inlet end 2 and out through the outlet end 3 so that the blood flow through the vessel is substantially uninterrupted, but the blood is prevented from exsanguinating through the damaged wall of the vessel (or is prevented from passing into the branching vessel) , as illustrated in Figs. 8(a) and (b) . The cotton thread 20 has the effect of facilitating the removal of the saline (or other inflation fluid) from the inflatable device, prior to the removal of the device from the patient's body. The cotton thread 20 prevents opposing wall portions of each pipe segment 10 to 17 from collapsing flat against each other whereby the saline could be trapped within proportions of one or more of the pipe segments causing differential collapse of the tube ie portions of the inflated tube may collapse/deflate while other portions may remain inflated. The presence of the cotton thread ensures that the hollow interior of the pipe does not get blocked/sealed off at any point, thus preventing such differential collapse from happening. In alternative possible embodiments other elongate bodies may be provided inside the inflatable pipe segments 10 to 17, rather than a cotton thread 20, to perform this function such, as for example an elongate plastic body having a plurality of radially extending lobes. Alternatively the walls of the pipe segments 10 to 17 could themselves be configured so as to prevent them from collapsing flat against one another. Although the device of Figs. 1 to 4 is inflated by means of the saline inlet port 18 provided at the inlet end 2 on the tubular device, in other embodiments the saline entry port may be provided at other locations on the inflatable device 1. For example, the device 1 may be designed so that the saline entry port is positioned approximately mid-way along the length of the inflatable device 1. Moreover, in practice the most convenient way of deploying the device inside the patient may be by means of a catheter. Fig. 5 shows a modified version of the device of Figs. 1 to 4 attached to a catheter 30. The device 1' differs from the device 1 of Figs. 1 to 4 only in that instead of being connected to a saline delivery pipe 20 the device is provided with two inlet/outlet ports via which saline may enter/exit the inflatable volume of the device and these inlet/outlet ports (not shown) are provided on the inner surface of the tubular device. The catheter 30 is provided with respective saline entry/exit ports 32, 34 which are in fluid communication with these inlet/outlet ports of the device 1' (the saline entry/exit ports 32,34 of the catheter are bonded, glued or otherwise permanently attached to the inlet/outlet ports of the tubular device) . As can be seen more clearly from Fig.6, the catheter 30 is provided with a saline feeding channel 35 via which saline is fed to the entry/exit ports 32, 34 to inflate the device 1' . The catheter 30 passes through the hollow central passage 4 of the tubular device 1' as shown in Fig.5. In use of the device cathether 30 is fed over a guidewire 40 inserted into the patient. The cathether 30, via its attachment to the device 1' at the entry/exit ports 32, 34, may be used to effectively tow the device 1' to the desired location in the patient. The saline would be injected out of a syringe into the saline feeding channel 35 of the catheter 30 via a Luer lock. Luer locks are well known in the art, a Luer lock basically consisting of a valve which keeps the saline in the inflatable device when the syringe is removed from the valve but which allows the saline to flow in either direction (to inject or to extract) when the end of the syringe is pressed into the valve. Luer locks are very commonly used in medical devices especially in catheter and balloon combinations . Nevertheless there are also other possible applications for the device of Figs. 1 to 3 where it will not be attached to a catheter. For example, in one possible embodiment saline is injected straight into the balloon at a convenient point disposed on the side of the tubular form of the balloon, for example about half way along the length of the tubular form. This embodiment may be useful for providing a bridging and inter-position function to temporarily to replace a section of blood vessel, such as a section of the inferior vena cava (IVC) that has been removed during an operation. In this application the inflated device allows blood to continue to circulate in the vena cava without interruption. This would potentially be very useful in transplant surgery and in other operations where a portion of IVC has had to be removed. In such situations it may be desirable to use the inflatable device without having to attach it to a catheter since the surgeon may find that the catheter may get in his/her way during the procedure. In this case the saline will be held in the balloon by a Luer lock or a two-way tap valve. Also, the balloon may if desired in this case be inflated using a suitable gas, for example carbon dioxide (C0₂) , rather than saline. The preferred method for manufacturing the device of Figs . 1 to 4 will now be described in detail with reference to Figs. 7(a) to (n) . Firstly a flexible pipe 42 made of extruded polyolefin is cut to the desired length which in this embodiment is approximately 200mm. Polyolefin is a heat shrinkable material which will bond to itself under sufficient temperature and/or pressure. (Other materials having this property could alternatively be used) . A longer length of cotton thread 44 is then cut from a spool of such thread. The resulting thread 44 is then threaded through the flexible pipe 42 using a wire hoop 45 to pull the thread through the pipe. One end 43 of the pipe 42 is then heated and folded over on itself to trap one end of the cotton thread therein. A short length of heat shrink tubing 46 is then pushed onto the folded end of the tube 42 and shrunk with a hot air gun. The pipe 42 now forms an inflatable pipe. This inflatable pipe is then processed in a vertical oven 50 so as to stretch the pipe, in this case from a length of 200 millimetres up to a length of approximately 940 millimetres. The cotton thread 44 inside the inflatable pipe stops the pipe being overstretched. The pipe 42 is positioned inside the vertical oven for stretching by suspending it in the oven by means of the free end 47 of the cotton thread 44, and attaching to the sealed end of the inflatable pipe 42 a weight W of 25 grams. Heat is applied via heaters 52 mounted on the walls of the vertical oven. In the device of Figs. 1 to 4, where saline is pumped into the device via the saline entry port 18 provided at the inlet end of the device, it is necessary to attach the saline feed tube 20 to the device 1. This is done using the process illustrated in Figs. 7(g) and (h) which illustrate a PVC saline feed tube 20 being connected to the free end 18 of the final pipe segment 17 via a Teflon bridging tube 55. A sleeve 60 of heat shrink material is threaded over the join and shrunk onto it (by applying heat) so as to trap the free end 47 of the cotton between the Teflon tube 55 and the heat sleeve 60, and so as to seal the join between the PVC tube 20 and the inflatable pipe 42. Fig. 7(1) is a schematic cross-sectional view of the assembled device 1 thus assembled (the cross-sectioned taken along the axis of the inflatable pipe 42). Figs. 7(i) to 7 (n) illustrate how the tubular shape of the device 1 is formed from the inflatable pipe 42. The (deflated) pipe 42 is wound onto a Teflon coated aluminium tube 70 at opposite ends of which a series of Teflon coated pins 80 are screwed into the aluminium tube 70. Four pins 80 are provided at each end of the aluminium tube, equidistantly spaced around the circumference of the tube. The inflatable tube is wound onto the pins so as to pass up and down along the length of the aluminium tube, as illustrated schematically in Fig. 7(j), so as to form seven U-bends 8 in the inflatable pipe 42, and eight pipe segments 10 to 17 extending therebetween. The aluminium tube 70 with the inflatable pipe wound thereon as described is then placed inside a Teflon lined glass outer tube 85. The inflatable tube 42 is then pressurised by pumping air into it via the PVC tube 20 and a thermocouple is attached to the aluminium tube 70 for heat measurement. The whole assembly is then placed in an oven which is cycled to 130°C approximately whilst air pressure of approximately 200 to 300 millibars is pumped into the inflatable tube. The device inflates to fill the space between adjacent pipe segments and as the walls of the adjacent pipe segments come into contact with one another they will bond together (providing the pipe segments 10 to 17 are close enough together on the aluminium tube) . The assembly is then removed from the oven but the air pressure is maintained to the inflatable pipe while the assembly cools. The air pressure is then released and the aluminium tube 70 is removed from the glass outer tube 85. The Teflon coated pins 80 are then unscrewed to ^• release the formed device 1 from the tube 70. It will be appreciated that various modifications to the above described embodiments and procedures are possible within the scope of the invention. For example, the device 1 may be designed to have different sizes depending on the intended applications of the device. For example, in some embodiments the inflatable tube 42 may be wound up and down a greater number of times in order to form more than eight pipe segments 10 - 17. For example, Fig. 9 is an end view of a larger diameter device having six U-bends 90 formed in the illustrated end of the device. In general, depending on the diameter of the blood vessel or other body vessel in which the device 1 is intended to be deployed, the device 1 will be manufactured with an appropriate outer and inner diameter. In practice, it may be desirable to deploy the deflated device into the body inside a protective housing or sheath which covers the device but from which the deflated device is extracted or retracted prior to positioning the device in its desired operative position in which it will be inflated. With this in mind, the inlet and outlet ends 2, 3 of the device 1 may conveniently be designed such that they are effectively disposed at an angle to the axis of the tubular form of the device, in particular slanted in opposite directions at the opposing ends of the tube as shown in Fig. 10. The advantage of such a structure is that it would be much easier to extract or retract the balloon from/into such an outer housing or sheath than if the balloon were to have inlet and outlet ends disposed perpendicular to the axis of the device. It will slide in and out more easily. The sheath itself, housing the deflated balloon, would be deployed into a target blood vessel of the body via a Seldinger sheath arrangement (well-known in the art) which acts as a conduit from outside the body to inside the blood vessel. Such an insertion process is described in WO 01/47594. In addition to slanting the ends of the balloon as shown in Fig. 10, in another possible embodiment the whole tubular structure is crimped along its length (like pleats in a skirt) so that it is easier to get the tube into a sheath in the first place. This technique is quite commonly used in the manufacturing processes of other known balloon devices, in order to get a large volume into a small space. By rotating the balloon in the direction of the folds as the balloon is withdrawn back into its sheath, it will be easier to rehouse the balloon in the sheath as the pleats reform and thus the balloon will be easier to extract . In another possible modified embodiment the cross- section of each of the pipe segments 10 to 17 may have a voussoir shape, as illustrated in Fig.12, whereby the outer surface of the inflated device 1 fits even more closely to the inner wall (i.e. intima) of the blood vessel 26 in use as compared with the device of Figs.1-4; Where extrusion techniques are used to manufacture the inflatable pipe this may be achieved by extruding the inflatable pipe (which forms the pipe segments) in a voussoir-shaped cross-section rather than the generally circular cross-section of the pipe used in the device of Figs. 1 to 4. The proposed material from which the above described inflatable device is made, namely polyolefin, has been chosen due to its ability to bond to itself under sufficient temperature and pressure. It is expected that this material is physiologically compatible. However, should it be the case that this material is found to encourage the formation of blood clots it is proposed that the device 1 shall be heparin-bonded (i.e. coated) so as to avoid any thrombogenic action of the device 1 in use thereof. Alternatively, materials already known to be physiologically compatible may be used to form the inflatable device if they are capable of bonding to themselves under achievable temperatures and/or pressures, or if alternative means for bonding the adjacent pipe segments 10 - 17 are used, for example, using an appropriate adhesive to bond the adjacent pipe segments. Finally, the above-described device 1 could be designed for use in pipeline industries, instead of for surgical use. In this case the device would be manufactured to a larger size designed to fit closely to the interior diameter of the pipeline in which it is intended to be used, and may also need to be manufactured from stronger materials more suited to the intended pipeline application. However, the principle of operation of the device would remain the same. In use, the deflated device 1 would be inserted into, for example a damaged oil or gas pipeline, and positioned adjacent the damaged portion of the pipeline (in a similar manner to that shown in Fig.8(a)). The device would then be inflated so as to prevent fluid in the pipeline from leaking out of the damaged portion, but allowing the fluid to continue to flow through the pipeline by flowing through the open-ended tubular form of the inflated device. Equally, the device 1 could be deployed to bridge a gap 68 in a pipeline 70, to allow a damaged portion of the pipeline to be removed for repair, as illustrated in Fig.11.

Claims

CLAI S

1. An inflatable device (1) for inserting, in a substantially deflated state, into a tubular duct, the device having an inflated state in which it defines an elongate open-ended tube having an inlet end and an outlet end, said tube having an outer surface formed and arranged to fit, in said inflated state of the device, closely to the interior surface of the tubular duct in use of the device, whereby, in use of the device in its inflated state, fluid or other matter carried by the duct may pass through the tube via the inlet and outlet ends thereof , wherein said tube comprises collapsible walls defining an inflatable pipe which is bent back on itself at a plurality of locations to form a multiplicity of parallel pipe segments (10-17) extending substantially parallel to an axis of said tube, the walls of adjacent pipe segments being bonded to one another so as to form said open-ended tube.

2. The inflatable device according to claim 1, wherein the device further includes an elongate object disposed inside the inflatable pipe, in the inflatable volume thereof, for substantially preventing differential collapse of the tube when the tube is being deflated.

3. An inflatable device according to claim 2, wherein the device is suitable for surgical application and the elongate object comprises a length of thread running through the hollow interior of the inflatable pipe.

4. An inflatable device according to claim 2, wherein the device is suitable for surgical application and the collapsible walls are configured so that they are substantially prevented from lying flat against one another when the device is deflated.

5. An inflatable device according to any preceding claim, wherein the collapsible walls of the device are formed from a material which bonds to itself when subjected to a sufficiently high temperature and/or pressure.

6. An inflatable device according to any preceding claim, wherein one end of the inflatable pipe is sealed off and the other end is attached to, and in fluid communication with, an inflation fluid delivery pipe via which inflation fluid may be delivered to the hollow interior of the pipe to inflate the pipe.

7. An inflatable device according to any of claims 1 to 5, wherein the device is suitable for surgical application and the device is attached to a catheter via which an inflation fluid for inflating the device may be delivered to the device .

8. An inflatable device according to claim 7, wherein the device is provided with at least one input/output port for attachment to the catheter, each said input/output port being in fluid communication with the hollow interior of the inflatable pipe.

9. An inflatable device according to claim 8, wherein each said input/output port on the inflatable device is located on an inner surface of the open-ended tube, such that the catheter extends into or through the tube.

10. An inflatable device according to any preceding claim, wherein the inflatable pipe has a substantially circularly- shaped cross-section.

11. An inflatable device according to any of claims 1 to 9, wherein the inflatable pipe has a voussoir-shaped cross- section.

12. An inflatable device according to claim 1 or claim 2, wherein the device is suitable for use in a tubular duct in the form of an industrial pipeline.

13. A method of repairing a damaged industrial pipeline comprising the steps of: inserting the deflated device of claim 12 into the damaged pipeline; positioning the device adjacent the damaged portion of the pipeline and inflating the device such that fluid in the pipeline is prevented from leaking out of the damaged portion of the pipeline, but the fluid is allowed to continue to flow through the open-ended tubular form of the inflated device.

14. A kit-of-parts comprising the inflatable device according to any of claims 1 to 13, for inserting into a tubular duct, and insertion means for facilitating access to the inside of said tubular duct.

15. A kit-of-parts according to claim 14, further including deployment means for deploying the device to its inflated state.

16. A method of manufacturing an inflatable device for inserting, in a substantially deflated state, into a tubular duct in a human or animal, the method comprising the steps of: providing an open-ended inflatable pipe made of a material which bonds to itself when subjected to a sufficiently high temperature and/or pressure; sealing off one end of this pipe; providing an elongate baking tool comprising a cylinder having a plurality of winding pins arranged in two spaced apart sets of pins, each set comprising a plurality of pins extending radially outwardly from the cylinder and disposed around the circumference of the cylinder; winding the inflatable pipe, in its deflated state, around the winding pins provided on the baking tool so as to wind the pipe up and down along the length of the cylinder so as to form a multiplicity of substantially parallel pipe segments arranged in close relationship to one another around the full circumference of the cylinder; inflating the pipe under pressure and applying sufficient heat to the pressurised pipe that adjacent inflated pipe segments are bonded together, thereby forming an open-ended tube; releasing the bonded pipe from the winding pins of the baking tool.

17. A method according to claim 16, further including threading a cotton thread through the inflatable pipe prior to sealing off said one end of the pipe.

18. The method according to claim 16, further including attaching an inflation fluid delivery tube to the other end of the inflatable pipe prior to winding the pipe onto the baking tool.

19. The method according to any of claims 16 to 18, wherein the inflatable pipe is made of heat shrink material and the pipe is heat-stretched under pressure prior to winding it around the baking tool .

20. An inflatable device substantially as described herein and with to Figs. 1 to 3.

21. A method of manufacturing the inflatable device of Figs.l to 3 substantially as described herein and with reference to Figs. 7(a) to (n) .