WO2021224248A1

WO2021224248A1 - Catheter

Info

Publication number: WO2021224248A1
Application number: PCT/EP2021/061715
Authority: WO
Inventors: Nawar AL-ZEBARI
Original assignee: Urologic Limited
Priority date: 2020-05-04
Filing date: 2021-05-04
Publication date: 2021-11-11
Also published as: GB2594711A; GB202006521D0

Abstract

The invention relates to a catheter (100) comprising a tip member (10) at its distal end (120), an elongated tube (20), and a retention mechanism (30), said retention mechanism (30) comprising a plurality of wings (31) provided with shape memory alloy wires (40) configured to cause the wings (31) to transition from a deactivated shape (41) for passing through a bodily channel during insertion and/or removal of the catheter (100) from a bodily cavity, to an activated shape (42) for retention of the catheter (100) inside the bodily cavity. Each wing (31) has a distal extremity (33) connected to the tip member (10) at least during insertion of the catheter (100) and a proximal extremity (32) connected to the elongated tube (20) at least when the wings (31) are in activated shape (42).

Description

CATHETER

[001] The present invention relates to a catheter for inserting through a bodily channel into a bodily cavity for instance to facilitate drainage, for sampling, and/or for administration of substances into the bodily cavity.

Background of the invention

[002] Catheters are designed to be inserted through a bodily channel into a bodily cavity of a patient such that part of the catheter stays inside said cavity for the duration of certain procedures or longer, maintaining fluid communication between said cavity and the exterior of the body of the patient, for example to ensure drainage of said cavity. In chronic medical and surgical conditions, the catheter may have to remain in place for weeks, months, or in some cases for life. In order to avoid the accidental removal of the catheter from the bodily cavity, catheters have been provided with various retention mechanisms.

[003] The Foley catheter is a common type of indwelling urethral catheter provided with an inflatable balloon towards the distal end (the bladder end) of the catheter tube. The balloon is in deflated state when the catheter is introduced through the urethra into the bladder, and is then inflated with water through a separate lumen in the catheter tube. Once inflated, the balloon acts as a retention mechanism at the entrance of the bladder, preventing the catheter from being withdrawn accidentally. Eyelets for drainage of urine are made into the catheter tube above the balloon, at the distal end of the catheter. This design has the disadvantage that it prevents full drainage of the bladder; the placing of the drainage eyelets above the balloon creates below a pool of stagnant urine. This stagnant urine favors the proliferation of harmful bacteria that lead to infections and encrustations which can, in turn, lead to catheter blockage. Also, the Foley catheter requires the balloon to be inflated after insertion, resulting in an additional step during insertion requiring more time and leading to potential complications such as balloon rupture and urethral damage during inflation or removal.

[004] The “Malecot Catheter” is a well-known intermittent catheter. It comprises a retention mechanism at the distal end of the catheter tube made of a plurality of soft, flexible wings which can be collapsed from a radially expanding, open position into a compressed position. When the catheter is inserted through the urethra, said wings, known as “Malecot wings”, collapse elastically into the compressed position, allowing the catheter to pass through, and they revert elastically to the open position once the retention mechanism has passed into the bladder. When the wings are in open position, a drainage orifice at the end of the tube is uncovered. However, the Malecot catheter is mainly used as an intermittent catheter and not as an indwelling catheter, because its retention mechanism made of soft, flexible wings is not stable enough to remain in the bladder without accidental removal, and the catheter falls out easily.

[005] UK patent application GB2532212 discloses an indwelling urethral catheter having at its distal end a retention mechanism made of shape memory material, preferably a temperature sensitive polymer. The disclosed retention mechanism is in the form of a split tube having two or more memory shape members that maintain an elongated shape during insertion and split out, curling outwards, after insertion. Such memory shape members however pose a high risk of inducing trauma in a patient, for example during insertion, since they need to be made of a strong, rigid material such as a blend of polyurethane/ poly(lactic acid)/PEG in order to maintain their elongate shape. Moreover, they will also tend to split out while in the urethra, especially in case of prostate enlargement areas constricting the urethra, which can lead to insertion blockages and to injuries. There is also a risk that said members will cause injuries to the bladder when they curl outwards after insertion. Moreover, temperature sensitive polymers have a broad activation temperature, so in order to soften the polymer higher temperatures need to be reached (in excess to 42 °C) which could damage the tissues such as mucosa and bladder lining. Also with polymers the stiffness of the retention mechanism after insertion into the bladder cannot be effectively and easily controlled to ensure a safe retention of the catheter.

[006] Accordingly, it is desirable to provide a catheter which remains stable in the bodily cavity during use, but at the same time is easy to insert and remove, with reduced risk of trauma. With a catheter according to the present invention, it is possible to enhance draining efficiency and to lower the risks of infection. In particular, a urinary catheter according to the invention enhances draining efficiency of the bladder while at the same time prevents trauma and accidental removal, and lowers the risk of infection. Summary of the invention

[007] In accordance to a first aspect, there is provided a catheter having a distal end for insertion through a bodily channel into bodily cavity and a proximal end for manipulating the catheter during insertion and/or removal from said bodily cavity, the catheter comprising: a) a tip member at the distal end of the catheter; b) a retention mechanism (30) comprising a plurality of wings each having a distal extremity placed in contact with the tip member and a proximal extremity, wherein said wings are provided with shape memory alloy wires configured to cause the wings to transition from a deactivated shape for passing through the bodily channel, guided by the tip member, during insertion of the catheter, to an activated shape for retention of the wings inside the cavity in order to prevent the removal of the catheter; and c) an elongated tube configured to allow circulation of a fluid to and/or from the bodily cavity, wherein, in the activated shape, the elongated tube is abutting the proximal extremity of said wings.

[008] According to the present invention, the removal of the catheter from the bodily cavity may be performed in any way, as long as the wings can be caused to transition to a shape suitable for facilitating the passing through the bodily channel. For example, the wings may be caused to transition from an activated to a deactivated shape by the shape memory alloy wires transitioning from an activated to a deactivated shape, respectively. Thus, the removal of the catheter from the bodily cavity takes place in the deactivated shape. In another example, the shape memory alloy wires may be removed from the retention mechanism before removal of the catheter.

Definitions

[009] The catheter of the invention may be any kind of catheter, such as intravenous (IV) catheters, umbilical artery catheters, infusion catheters, nasogastric catheters, peritoneal dialysis catheter, haemodialysis catheters, feeding catheters, breathing catheters, cardiac catheters, stomal catheters, suprapubic catheters, nephrostomy catheters, intermittent catheters, pus removal catheters, urethral dilating catheter, cardiovascular dilating catheters. In preferred embodiments, the catheter is an indwelling catheter. More preferably it is an indwelling urinary catheter.

[010] Said bodily cavity may be any cavity in the body where a catheter may be introduced, such as for example the bladder or the stomach. Said bodily channel may be any channel reaching into a bodily cavity, such as for example a natural channel such as the urethra or the digestive tube or a channel executed by a surgeon through the body tissues of a human or animal.

[011] The catheter of the present invention is designed to be inserted at least partly in a bodily cavity of a human or animal. By insertion of the catheter it is meant the introduction of said catheter through a bodily channel in the direction of a bodily cavity. A catheter is functionally inserted into a bodily cavity when at least the retention mechanism of the catheter has been enclosed in the bodily cavity, such that the retention mechanism can fulfill its function of preventing the catheter from leaving the bodily cavity while at the same time a fluid communication is ensured between the bodily cavity and the exterior of the body of a patient. The wording “catheter inserted in the bodily cavity” refers to a catheter wherein at least the retention mechanism is inserted into the bodily cavity.

[012] Throughout the present disclosure, by “distal” end of the catheter it is meant the end thereof that first contacts the bodily channel when the catheter is inserted. Similarly, by “proximal” end of the catheter, it is understood the end situated at the other extremity of the catheter than the “distal” end. The proximal end of the catheter usually remains outside the bodily cavity and the bodily channel, while the rest of the catheter will be accommodated therein.

Also throughout the present disclosure, by “distal” end, area, part or extremity of an element of the catheter it is meant the end, area, part or extremity of that element which is closer to the distal end of the catheter. Similarly, by “proximal” end, area, part or extremity of an element it is meant the end, area, part or extremity of that element which is closer to the proximal end of the catheter.

[013] In the present disclosure, by “inner” side of the catheter or of an element of the catheter such as the tip member or the elongated tube, it is meant the side facing towards the interior of the catheter or element thereof, namely towards the space where fluid can flow through the catheter, such as towards the lumen of the elongated tube. By “outer” side of the catheter or of an element of the catheter such as the tip member or the elongated tube, it is meant the opposite side than the inner side, facing towards the exterior of the catheter or element thereof.

Tip member

[014] The tip member, according to the invention, represents the element that ends the catheter and is situated at the distal end thereof. The tip member may be made of the same or different material with the elongated tube or the retention mechanism.

[015] In one embodiment, the tip member is made of a material that is stiffer than the material of the elongated tube, for an easier guidance during insertion. Also for an easy insertion, the tip member may have a diameter smaller than the diameter of the elongated tube.

[016] In preferred embodiments, the tip member comprises a spherical or elongated (whistle-tip) member at its distal end that allows for a smooth and less traumatic insertion of the catheter and for better guidance during insertion.

[017] The tip member is configured to facilitate a smooth and easy insertion of the catheter. A catheter according to the present invention has a retention mechanism designed to keep the catheter in place, after insertion thereof into the bodily cavity. To perform this function, the retention mechanism comprises two or more wings that transition between a deactivated and an activated shape. Said wings have distal extremities that are separate and free of each other. At least during insertion of the catheter into the bodily cavity, said distal extremities are placed in contact with the tip member. In the absence of the tip member, during insertion of the catheter, the proximal extremities of the wings would tend to move away from each other, and the edges of the wings would tend to wound the walls of the channel, which is normally narrow and not straight. By ensuring that the tip member is at the distal end of the catheter and in contact with the wings during insertion, such a risk is eliminated.

[018] After insertion, the tip member may remain in place or alternatively may be removed. [019] In some embodiments, the tip member remains in place such that the wings are connected to the tip member also when the wings are in activated shape. In these embodiments, the distal extremities of the wings may be integrally formed with the tip member or attached to it, for example by melding or gluing. In these embodiments, the tip member is not removable and will remain connected to the distal extremities of the wings also when in activated shape. For better guidance and a smooth passage through the bodily channel, the tip member of these embodiments may have a spherical or elongated shape. In one preferred embodiment, the tip member comprises a narrow, flexible neck and a spherical distal extremity. The flexible neck has a diameter that is equal or smaller than the diameter of the elongated tube and also smaller than the diameter of said spherical distal extremity. The flexible neck is connected to the retention mechanism, optionally such that the SMA wires continue from the wings into the flexible neck. The SMA wires in the neck remain soft and flexible during insertion, and become stiffer in the bodily cavity, after they transition into activated shape. The spherical extremity enables an easier passage and the flexible neck allows the bending/flexing to facilitate the guidance through the bodily channel into the bodily cavity.

[020] In other embodiments, the tip member may be removed, i.e. the distal extremities of the wings are releasably connected to the tip member. The wings according to these embodiments are connected to the tip member during insertion, while in deactivated shape, and are no longer connected to the tip member when in activated shape.

In preferred embodiments, the tip member releasably connected to the wings comprises a recess and the distal extremities of the wings are housed inside the recess cavity during insertion of the catheter.

[021] In these embodiments, the tip member is configured to be removed after insertion of the wings into the bodily cavity. Preferably, the wings of these embodiments are configured such that, when the distal extremities of the wings are housed inside the tip member, the wings are not able to transition from the deactivated shape into the activated shape. For example, in one preferred embodiment, the SMA wires are trained to cause the wings to open in the activated shape radially, like the petals of a flower, starting from the distal extremities, such that, as long as the tip member houses the distal extremities of the wings, they are not able to change shape. Only after the tip member is removed, the wings will be able to transition to the activated shape. Consequently, the tip member of this embodiment not only facilitates a smooth insertion, but also prevents the wings from transiting from the deactivated shape into the activated shape, ensuring that the wings do not prematurely open, so even when the insertion takes a longer time, potential trauma is avoided.

[022] Advantageously, the removable tip member of these embodiments may have at least the area holding the wings made from an elastic material, thus being able to hold the distal extremities of the wings tightly and securely during insertion and then to assume a narrower shape after releasing the wings, so it can easily pass through the elongated tube. Also advantageously, the tip member and the retention mechanism in this embodiment are narrower and stiffer than the elongated tube, facilitating an easy insertion.

[023] The removal of the tip member may be performed, for example, by the help of a handle, such as a wire. In a preferred example, said handle is attached to the tip member, extends through the retention mechanism and the elongated tube and reaches the proximal end of the catheter, where it can be used by a user to manipulate the tip member. For removing the tip member, said handle can be pushed in a direction from the proximal to the distal end of the catheter, until the wings are released, and after the wings transition into activated shape it is pulled in the opposite direction through the elongated tube and removed.

[024] It represents therefore another aspect of the present invention a method for insertion of the catheter of this embodiment, comprising the steps: a) inserting through a bodily channel into a bodily cavity a catheter of the invention wherein the distal extremities of the wings are releasably connected to the tip member; b) releasing the wings from the tip member, c) allowing the wings to transition into activated shape, and d) removing the tip member.

[025] In preferred embodiments, the tip member may be provided with a hole for fitting a guiding device such as a camera, enabling the user to see in advance, for example during insertion of the catheter, possible obstacles by avoiding them before any trauma is induced to the patient and monitor general health of bladder. [026] Also in some embodiments the tip member may be provided with at least one drainage lumen configured to allow the passage of fluids from the exterior of the catheter (such as from the bodily cavity) to the lumen of the catheter and vice-versa. Said drainage lumen allows for the drainage of fluids from the bodily cavity even without the activation of the retention mechanism, and/or for administering of fluids into the body before or without activating the retention mechanism. In a preferred embodiment, said lumen extends longitudinally from the distal to the proximal end of the tip member. The tip member may be further provided at its distal end with splits or slots converging into said drainage lumen, for facilitating a more efficient draining.

Elongated tube

[027] The elongated tube of the catheter of the invention comprises a tubular member with dimensions suitable for insertion through a bodily channel, the tubular member defining a longitudinal channel having a wall and a lumen adapted for passage of fluids therethrough along a longitudinal axis from the distal end to the proximal end of the elongated tube.

[028] In some embodiments, the elongated tube is integrally formed with the retention mechanism. In a preferred embodiment, a plurality of longitudinal splits, preferably four splits, are performed in a tube, in the vicinity of the distal end, to obtain Malecot-like wings of the retention mechanism. In another preferred embodiment, the distal end of a tube may be split to obtain petal-like wings of the retention mechanism. Therefore, the catheter can be obtained by an easy and inexpensive production process.

[029] In other embodiments, the elongated tube is slidable between a first position in the deactivated shape at least partially covering the retention mechanism and a second position in the activated shape, exposing the retention mechanism. In the activated shape, the elongated tube abuts the proximal extremities of the wings. The elongated tube at least partially covers the retention mechanism in this embodiment, such that it prevents the wings to transition from the deactivated shape into the activated shape. This represents a safety feature against the premature activation of the SMA wires and transition of the wings, for example in case the insertion takes longer than usual. [030] After insertion into the bodily cavity, the slidable elongated tube is pulled towards the proximal end of the catheter to reach a second position, thus uncovering the retention mechanism and allowing the wings to transition into the activated shape. The shape of the wings in activated shape is such that the elongated tube is maintained in place abutting the proximal extremities of the wings and that the opening at the end of the elongated tube is exposed, positioned at the entrance of the bodily cavity. This facilitates an efficient fluid communication between the bodily cavity and the exterior of the body, in particular an efficient drainage of the bodily cavity.

[031] During removal of the catheter, after the wings have been allowed to transition to the deactivated shape, the elongated tube may be pushed back in the first position covering the retention mechanism, to ensure that the wings have been totally collapsed before removing the catheter through the bodily channel, so that no trauma occurs.

[032] In a preferred embodiment, the catheter of the invention comprises: a) a tip member, b) a retention mechanism comprising a plurality of wings, each wing having

- a distal extremity formed with the tip member,

- a proximal extremity abutting the elongated tube when the wing is in activated shape; c) extensions of the wings, extending from the proximal extremities of each wing to the proximal end of the catheter, and d) an elongated tube that is slideable between a first position in the deactivated shape at least partially covering the retention mechanism and a second position in the activated shape, uncovering the retention mechanism, wherein the elongated tube abuts the proximal extremities of the wings.

[033] During insertion and/or removal of the catheter, at least part of the wings is housed inside the elongated tube, while part of the extensions protrudes outside the elongated tube, at the proximal end of the catheter. Preferably, the extensions of the wings have a length such that, at least when the wings are in deactivated shape, the extensions protrude outside the body, such that they can be manipulated by a user. More specifically, the parts of the extensions which remain outside can be manipulated by a user to help guiding the catheter during insertion and/or removal of the catheter by pulling and/or pushing said extensions in different directions for example to avoid problem areas in the bodily channel. In this embodiment, said extensions of the wings may be made by the same or different material as the wings, Said extensions may be provided with wires, for example extending from the SMA wires in the wings, for rendering the extensions more rigid.

[034] In a preferred embodiment, during insertion and/or removal of the catheter, the slidable elongated tube abuts the tip member, housing the entire retention mechanism. In this embodiment, the catheter is inserted by pushing the elongated tube against the tip member. This secures the wings in a deactivated shape during insertion and/or removal, such that they do not transition to the activated shape before the desired time due to, for example, an increase in temperature when the catheter is inserted into the body.

[035] In another embodiment, the catheter of the invention is provided, at or near its proximal end, with at least one valve for preventing undesired drainage and/or the backflow of the fluid. Said at least one valve is preferably placed at or near the proximal end of the elongated tube such that it remains outside the body during the use of the catheter, so that it can be easily manipulated. Preferably, said at least one valve is provided at or near the proximal end of the elongated tube such that a syringe or similar device can be pushed through the valve to allow the catheter to be drained if blocked or for irrigating the bodily cavity with a fluid, such as with a liquid at room temperature for deactivating the SMA wires.

Preferably, said at least one valve is a one-way valve (also known as check valve), which may be chosen from any check valves suitable for being placed within the elongated tube of a catheter, such as ball cracking valves, diaphragm cracking valves, butterfly cracking valves.

Said at least one valve can prevent the fluid drained through the catheter into an attached bag for collecting the fluid to flow back towards the bodily cavity. Moreover, since said valve prevents the draining of fluid outside the catheter, such a catheter can be used even without a bag for collecting the fluid, which reduces the amount of materials needed for the manufacturing and use of the catheter, and could be useful for active, independent patients. The patient or a caregiver can allow the fluid to drain only when needed or desired, by pinching the valve with the fingers to release the fluid. Alternatively, and as a safety feature, when the pressure of accumulated fluid surpasses a set threshold of the valve (also known as cracking pressure of the valve), the valve opens, and the fluid is drained. For example, for a urinary catheter, said at least one valve prevents urine from the bag to flow back towards the bladder, and it also allows the bladder to fill up before being emptied. Therefore, said valve allows the bladder to function physiologically, filling up before being emptied either voluntarily (by pinching the valve) or naturally (due to the pressure of the urine surpassing the cracking pressure of the valve). Consequently, there will be no need to retrain the bladder back to its normal functioning after the removal of the catheter. Moreover, such a urinary catheter can be used even without a urine bag, which is very useful for active, independent patients.

In preferred embodiments, the elongated tube of a catheter is provided at or near its proximal end with one one-way valve.

[036] In other embodiments, the elongated tube of a catheter is provided near its proximal end with two valves: one downstream, low pressure valve, and one upstream, high pressure valve. Said downstream, low pressure one-way valve is provided closer to the proximal end of the elongated tube. Preferably, at least the downstream valve, and more preferably both valves remain visible outside the body of the patient. In this embodiment, the upstream, high pressure valve has a cracking pressure that is higher than the cracking pressure of the downstream valve. When the fluid in the elongated tube reaches the high pressure threshold (cracking pressure) of the upstream valve, it is able to pass the upstream valve and it starts to flow into an in-between section of the elongated tube, which is the section of the tube lying between said upstream and downstream valves. The presence of fluid in said in-between space signals the patient or the caregiver that the fluid has reached the high pressure threshold of the upstream valve, enabling them to take the appropriate or desired measures (such as applying a bag to the proximal end of the tube, or pinching the valve(s) to drain the fluid). Thus, the present arrangement of two one way valves allows the catheter to be more safely used without a bag because it gives the user a time interval to become aware of the necessity of draining the fluid and to take the appropriate measures; namely the interval from the moment the first drop of fluid is present in said in-between section, and until the pressure of the fluid in said section reaches the cracking point of the low pressure valve. As mentioned before, this two-valve arrangement is especially advantageous in the case of the urinary catheters, because it also ensures that the bladder may fill up to the physiological pressure before being emptied. Said at least one valve, including the embodiment wherein the elongated tube is provided with one upstream and one downstream valve, may be provided and used with similar effects for any type of catheter, not only for the catheter of the present invention.

[037] In another embodiment, the proximal end the elongated tube is configured to be functionally connected to a peristaltic pump, for drainage or for administering liquids or for irrigation and cleaning of the bodily cavity. Advantageously, such a system comprising a urinary catheter together with a peristaltic pump may be used for removing debris and residues from the bladder. For the present embodiment, the elongated tube is preferably made of a strong material, suitable for being used as the tubing of a peristaltic pump without collapsing. Alternatively, a further tube that is sufficiently resilient may be introduced into the elongated tube at least for the length needed so that it can be used as tubing for a peristaltic pump.

Retention mechanism

[038] The retention mechanism of the catheter according to the invention has the role of keeping the catheter in place, after insertion thereof into the bodily cavity. To perform this function, the retention mechanism comprises two or more wings provided with Shape Memory Alloy wires, hereinafter also named SMA wires. Details about the SMA wires are provided later therein. When the SMA wires are activated, they change their shape from a deactivated shape to an activated shape, forcing at the same time the wings to take the shape thereof. Thus, in an activated shape, the wings reinforced by the SMA wires provide the necessary strength to the catheter to remain in a comfortable and secure position during use. Additionally, the catheter may comprise wings that are not provided with SMA wires. In preferred embodiments, the retention mechanism comprises two, three, four or six wings, preferably four wings.

[039] The wings have a distal extremity connected to the tip member at least during insertion of the catheter and a proximal extremity connected to the elongated tube at least when the wings are in activated shape. Said wings can transition from a deactivated shape for passing through the bodily channel during insertion and/or removal of the catheter from the bodily cavity, to an activated shape for retention of the catheter inside the bodily cavity. For example, in the deactivated shape, the wings are substantially elongated and compressed to allow the insertion through the bodily channel, and in the activated shape, the wings expand radially to prevent the removal of the retention mechanism from the bodily cavity. In preferred embodiments, the wings are arranged such that, in activated shape, the angles between any two consecutive wings are substantially equal. Such an arrangement ensures that the retention mechanism maintains a balanced, secure position at the entrance of the bodily cavity, keeping the drainage opening(s) in a stable position.

[040] In preferred embodiments, the retention mechanism in deactivated shape has a narrower diameter and is stiffer than the elongated tube, thus aiding guidance during insertion of the catheter. Such a narrower and stiffer retention mechanism is preferably used in a catheter having a tip member that is also stiffer and narrower than the elongated tube. The resulting stiff and narrow distal end of the catheter is especially beneficial in cases of difficult bodily channels, such as a urethra obstructed by an enlarged prostate, allowing for a better guided insertion and reducing the damage to the lining of the bodily channel during insertion of the catheter. For example, in a narrower and stiffer retention mechanism the wings are elongated and compressed towards each other in the deactivated shape. Said compression of the wings and also the increased rigidity may be achieved with the aid of the SMA wires. For example, the wires may be trained to slightly bend toward each other in deactivated shape, thus ensuring that the retention mechanism is narrower than the elongated tube and also sufficiently rigid for an easier insertion.

[041] In one embodiment, the catheter has a distal end for insertion through a bodily channel into a bodily cavity and a proximal end for manipulating the catheter during insertion and/or removal from the bodily cavity, the catheter comprising: a) a tip member at the distal end of the catheter; b) an elongated tube between the distal end and the proximal end, and c) a retention mechanism between the elongated tube and the tip member, the retention mechanism comprising a plurality of wings each having a proximal extremity connected to the elongated tube and a distal extremity connected to the tip member, wherein said wings are provided with shape memory alloy wires configured to cause the wings to transition from a deactivated shape for passing through the urethra during insertion and/or removal of the urinary catheter from the bladder, to an activated shape for retention of the urinary catheter inside the bladder.

[042] In a preferred embodiment of the present invention, the wings of the retention mechanism are Malecot-type wings, capable to extend from a substantially elongated shape into a so-called “Malecot shape” comprising a number of roughly semicircular, symmetrical wings. In activated shape, said Malecot-type wings of this embodiment abut the tip member at their distal extremity and the elongated tube at their distal extremity. Preferably, the retention mechanism has four substantially equal and symmetric Malecot-type wings. The use of symmetrically placed Malecot like wings has the advantage that they keep the retention mechanism firmly placed in the bodily cavity in the same position throughout long-time use, without the risk of accidental removal, partial removal, or obstruction of the drainage. Such risks are high in the case of less equilibrated shapes such as the spiral shape of the retention mechanism in some catheters. Moreover, due to the use of SMA wires, the wings of the catheter according to the present invention safely maintain the retention mechanism in the bodily cavity when in activated shape even when the curve of the wings to the longitudinal axis of the elongated tube reaches a maximum angle of less than 45°. In case of accidental removal, such wings will fold inwards, thus reducing the trauma as compared with other catheters (like for example the so-called Lotus catheter, wherein the wings reach almost 90° when fully deployed) that have retention mechanisms that fold outwards when accidentally removed.

[043] In preferred embodiments, the plurality of wings are connected to the elongated tube such that, when the wings are in the activated shape, an opening at the end of the elongated tube is exposed, allowing the drainage of a fluid from the bodily cavity. Said opening represents a drainage eyelet which is favorably placed at the outermost possible position in the bodily cavity, for efficient drainage. Preferably, said opening has the largest possible diameter, up to the diameter of the elongated tube, thus lessening the risk of catheter blockage due to encrustations. Such a position of the opening is, for example, especially advantageous for urinary catheters, allowing for a better drainage of urine. In a urinary catheter according to the present invention wherein the wings are Malecot-type wings, such as four wings opening symmetrically in the activated shape in a so-called “Malecot shape”, said opening is stably kept at the lowest possible position in the bladder. Keeping this lowest possible position means that the collection of stagnant urine at the base of the bladder is prevented, lowering the risk of infection.

[044] Alternatively, the elongated tube may be provided with a further portion extending from the connection of the elongated tube with the proximal extremities of the wings toward the tip member, said further portion being provided with multiple drainage holes. Preferably, said multiple drainage holes are placed at different heights around said further portion of the elongated tube. This further portion of the tube with multiple drainage holes will prevent mucus clogging up the tube. In this embodiment, the plurality of wings is connected to the elongated tube such that, when the wings are in activated shape, said further portion of the elongated tube is exposed, facilitating the drainage.

Materials

[045] The tip member, elongated tube and wings of the urinary catheter may be separately or integrally formed with one another, and are made of the same or different materials. Such materials suitable for manufacturing catheters are known to the person skilled in the art. Preferred materials are polyurethane, silicone, latex, PVC or styrene block co-polymers with ethylene butylene or ethylene propylene rubber (SIBS). More preferred materials are medical grade silicones and PTFE coated latex. Also, in preferred embodiments, the materials of the catheter are integrated with substances that inherently reduce bio-fouling and/or encrustation on the surface, such as chitosan, graphene and/or copper products.

[046] It represents an advantage of the urinary catheter of the invention that it may be made of collapsible, flexible and soft materials that allow for an easy and less traumatic insertion and/ or removal, while at the same time accidental removal of the catheter is prevented due to the retention mechanism according to the invention.

[047] In preferred embodiments, the elongated tube of the catheter is configured to transition from an open state while the bodily channel is physiologically in an open state to a closed, collapsed state while the bodily channel is physiologically in a closed state. By the wording “physiologically in an open/closed state” it is meant that the bodily channel assumes an open state when in use, to allow the passing of fluids, and a closed, relaxed state when not in use, when no fluid passes therethrough. This feature is for example useful for bodily channels that physiologically assume a closed, collapsed, flat, relaxed state when not in use, such as for example the urethra when not passing urine, and an open, extended state when in use, such as for example the urethra when passing urine. A catheter of the present embodiment allows the bodily channel to relax into the closed state when not in use and does not force it to remain for long periods of time in an extended, open state. Preferably, the elongated tube is made of materials, such as soft silicone, that are sufficiently collapsible, flexible and soft to allow for said transition.

[048] For example in the case of the urethra, while not in use, which is most of the time, the urethra remains in a collapsed, flat, closed state, and when urinating, its muscles contract to make it transition into an open state, only to relax again to the closed state after urinating. A catheter tube that forces the urethra to permanently remain in open state might put a strain on the urethral walls and on its blood vessels, which could in turn compromise the immunity against bacterial infections by limiting the blood flow. Moreover, such a catheter forcing the urethra for a long time into an open state can permanently increase the size of the urethra, leading to leakage after the removal of the catheter, and/or forcing the patients to subsequently use only supra-pubic catheters because their urethra is damaged. Therefore, it represents an advantageous feature of the present invention that the elongated tube of the catheter is made of materials sufficiently soft and elastic to allow the elongated tube to transition together with the urethra into a collapsed state when the urethra is not in use, and to transition back into an open state when the urethra is in use. Apart from avoiding putting strain on the urethra, the fact that the elongated tube remains in closed (collapsed) state while not urinating also has the advantage that the backflow of fluid is limited, which prevents bacteria from reaching the bladder.

[049] In a more preferred embodiment, the wall of the elongated tube is made of a soft, elastic, collapsible material such as soft silicone and it has a series of all-around troughs and crests of similar sizes projecting towards its lumen. Optionally, the elongated tube may be covered on the outside with a thin layer of another material (a skin), having a role of protection and/or resistance. The material of the skin may be the same or different than the material of the wall and may have the same or different hardness. In preferred embodiments, said wall is made of a material that is softer than said skin, such as a softer silicone. After the catheter is introduced into the bodily cavity, the elongated tube collapses into a closed state, wherein said troughs and crests interlock, ensuring that no backflow of fluid occurs. When in use, the muscles of the urethra make it transition to its physiologically open state, which in turn allows the soft, flexible tube to extend elastically to its open, circular state.

[050] In preferred embodiments, at least the inside surface of the elongated tube, namely its wall surface facing the lumen, is provided with a plurality of biodegradable layers such as polyelectrolyte coating layers, poly(a-hydroxy ester) or polylactide polymer layers, the layers being degradable or releasable layer-by-layer to wash away the bacteria during the drainage urine from the bodily cavity. Advantageously, such biodegradable layers may be also provided on the surfaces of the retention mechanism and tip member. The biodegradable layers degrade layer- by-layer and flush away with the fluids, together with any bacteria or encrustations that attach thereon, thus providing a cleaning mechanism that reduces bio-fouling and prevents the risk of infection. Said biodegradable layers may be obtained by coating the desired surface, for instance with biocompatible polyelectrolyte coatings such as chitosan or carrageenan. Alternatively, said biodegradable layers may be obtained by using an inherently degradable material for the catheter (tip member, elongated tube and/or retention mechanism), such as poly(a-hydroxy ester) polymers (PLA, PLLA, PLGA).

[051] Preferably, the outside surface of the catheter is at least partially coated with chitosan. This chitosan coating has anti-microbial and lubricating proprieties, thus preventing infections and facilitating an easy insertion.

SMA wires

[052] Shape memory alloy wires, also known as SMA wires, are thin flexible elongated threads made of special alloys, which can be made to transition between two shapes: a deactivated shape and an activated shape (or remembered shape), for instance under stress or due to changes in temperature. Such alloys are also known as memory alloys, memory metals, smart alloys, smart metals or muscle wires. Shape memory alloys are usually created using alloys of copper- aluminum-nickel, or nickel-titanium (NiTi), but different metals, such as Zn, Au or Fe may be used. [053] Each of the SMA wires of the catheter of the present invention may be made of the same or a different shape memory alloy. Thus, they may transit from their deactivated shape to the activated shape simultaneously and symmetrically or, alternatively, at different time intervals, allowing for specific needs and anatomic restrains of the bodily cavity or of the patient. Also, the SMA wires of the invention may be trained to have similar or different activated and/or deactivated shapes.

[054] In preferred embodiments of the invention, each of the SMA wires may be made of a superelastic SMA alloy, preferable nickel-titanium alloy (also known as Nitinol). Nitinol is preferred because it is biocompatible and has superior thermo-mechanical and elastic properties.

[055] In preferred embodiments, the material of the SMA wires is chosen so that the shape memory alloy wires have in activated shape a rigidity that is higher than their rigidity in deactivated shape. Consequently, the wires are soft, malleable and flexible in the deactivated shape, and become firmer and more rigid in the activated shape, capable of stably maintaining said activated shape. This means that a soft, flexible, collapsible material such as a soft silicone or latex can be used for the wings; during insertion and/or removal of the catheter, such wings provided with the soft, malleable and flexible SMA wires will remain soft, flexible and collapsible, making them advantageous to use for an easy, non-traumatic insertion. At the same time, the SMA wires become rigid and firm in activated shape, rendering the wings firm and stable in activated shape and thus removing risk of accidental falling out of the catheter.

[056] In one embodiment, the shape memory alloy wires extend towards the proximal end of the catheter to facilitate handling thereof during insertion and/or removal of the catheter. Such SMA wires extend outside the human or animal body and may be used to guide the catheter in different directions to avoid problem areas during insertion and/or removal of the catheter.

[057] In one embodiment, the deactivated shape is achieved when the shape memory alloy wires are below an activation temperature (AT), and the activated shape is achieved when the shape memory alloy wires reach the activation temperature AT. In a preferred embodiment, AT is conveniently set to about 27 to 42°C, plus or minus 5°C, such that the wires will transition into the activated shape when inserted into the living body, and maintain said activated shape in the bodily cavity, while remaining at body temperature. Within this range it is possible to use different temperatures for the activation/deactivation of the SMA wires in order to control the speed and duration of the activation/deactivation. This causes the wings of the catheter provided with the SMA wires to achieve the activated shape and to remain in this activated shape while at body temperature, thus preventing the accidental removal of the catheter from the bodily cavity.

[058] In this embodiment, the SMA wires cause the wings to transition from the activated shape to the deactivated shape upon cooling at a temperature below the activation temperature AT to allow the removal of the catheter from the bodily cavity via the channel. The SMA wires can transition to the deactivated shape by cooling at a temperature below the activation temperature AT, such as room temperature, thus causing the wings to achieve the deactivated shape and allowing the removal of the catheter from the bodily cavity via the bodily channel. Also, as described in more detail below, a manipulator can be used to aid in deactivating the wings.

[059] In preferred embodiments, the cooling of the SMA wires is achieved by irrigating the bodily cavity through the catheter with a fluid under the AT. For example, the bodily cavity is irrigated using a syringe with water or saline solution at about 25°C or less, preferably about 4° to 20°C. Alternatively, a chitosan gel or solution at room temperature (4° to 20°C) may be injected into the bodily cavity for cooling the SMA wires, providing further antibacterial properties and lubrication during removal of catheter. For example, flushing the bladder with cold water / saline solution / chitosan solution represents an important added benefit to the patient, having the further advantage that it leads to cleaning the bladder and removing of any potential clots or debris.

[060] Alternatively, such as when the irrigation of the bodily cavity is not indicated, the cooling of the SMA wires may be achieved by other means, such as, for example, placing ice on the body of the patient in the vicinity of the retention mechanism or using miniature thermoelectric micro coolers to locally reduce the temperature of the SMA wires using an electric supply.

[061] In another embodiment, the wings of the invention are provided with SMA wires that are trained to revert from the activated shape into the deactivated shape under mechanical stress, when a force is applied exceeding a predetermined threshold. This represents an additional safety feature in case of accidental pull or pull by distressed patients, preventing excessive damage to the bodily channel or a sphincter at the opening of the bodily channel into the bodily cavity.

[062] According to the invention, by wire it is meant any thin flexible elongated thread. Preferably, the SMA wires of the invention have a cylindrical shape (having a circular cross-section defined by its diameter). Each SMA wire may have the same or different diameters than the other SMA wires. The diameters of the wires are chosen in accordance with the size of the catheter in order to ensure optimal stability of the retention mechanism adapted to the thickness of the catheter / catheter wings. For example, for pediatric catheters the diameters of the catheters are smaller than in adults and therefore the retention pulling force is lower, which requires a smaller diameter of SMA wire in the retention mechanism.

[063] For urinary catheters it is for instance likely to use SMA wires with 0.6mm diameter for a catheter French size 14 and SMA wires with 0.4mm diameter for a catheter French size 10. In preferred embodiments, the SMA wires have diameters of between 0.1 to 0.9 mm, preferably about 0.3 to 0.6 mm.

[064] The wings of the invention are provided with SMA wires in any way that enables the SMA wires to cause said wings to transition from the deactivated shape into the activated shape and back.

[065] In one embodiment, the wings are provided with channels for hosting the SMA wires. In a preferred embodiment, said channels are integrated into the wings. Such wings with channels integrated into their wall can be smoothly inserted through the bodily channel. They are also easy to produce through a one-line extrusion process, making for an easy and inexpensive production process.

[066] In some embodiments, the SMA wires extend from the wings, optionally together with their housing channels, to the proximal end of the catheter, such that the proximal extremities of the SMA wires protrude outside the body of the patient, to facilitate the handling of the wires during insertion and/or removal of the catheter. This way, the wires can be alternatively pulled and/or pushed during the insertion and/or removal of the catheter in order to be able to pass areas with resistance. This is especially beneficial for difficult passages such as in cases of prostate enlargements constricting the urethra.

In a preferred embodiment, the SMA wires are configured to be removed from the wings of the catheter, for example by pulling on the proximal extremities of the SMA wires protruding at the proximal end of the catheter. For example, the SMA wires may be configured to move along their housing channels when pulled or pushed. Also, the SMA wires may be removed from the wings of the catheter when it is desired to remove the catheter. Without the SMA wires to make them more rigid, the wings elastically revert to and/or easily collapse into an elongated shape when pulled out, ensuring Without the SMA wires to make them more rigid, the wings easily collapse into an elongated shape when pulled out, ensuring a safe and atraumatic removal of the catheter from the bodily cavity. Thus, the catheter may be removed even without deactivation of the retention mechanism. This means that the SMA wires and the wings do not need to be transitioned to the deactivated shape, for instance by cooling, before the SMA wires are removed from the wings of the catheter and that the catheter can be safely removed from the bodily cavity without transitioning the SMA wires into the deactivated shape. This is especially useful in situations when cooling of the wings is not possible, convenient or recommended. Alternatively, the removal of the SMA wires may be performed as a safety measure after the SMA wires have been caused to transition to the deactivated shape, for example by cooling.

[067] In other preferred embodiments, the elongated tube of the catheter of the invention is provided with at least one further SMA wire configured to cause the elongated tube to transition from a retracted shape for insertion and/or removal of the catheter, to an extended shape for maintaining the elongated tube in position in the bodily channel and/or for maximizing the flow of fluid through the catheter. In retracted shape, the outer dimension of the tube in cross-section is reduced when compared with the outer dimension in cross-section in extended shape. In order to cause the elongated tube to make the transition from retracted to extended shape, said at least one further SMA wire transitions from a retracted shape to an extended shape. Said at least one further SMA wire may be further configured to cause the elongated tube to transition from the extended shape to the retracted shape, for example for an easy removal of the catheter.

[068] In preferred embodiments, each of said at least one further SMA wire defines a contour substantially perpendicular to the longitudinal axis of the elongated tube. In some embodiments, said contour of the further SMA wire(s) is a closed contour, preferably substantially in the shape of a circle when in extended shape. In retracted shape, said contour of said further SMA wire(s) assumes a shape with a smaller diameter than its diameter in extended shape, such as a scalloped shape, a horse-shoe shape or a shape with wavy edge. By the diameter of the contour in retracted shape is meant the maximum distance between two points of the contour.

[069] In preferred embodiments, the elongated tube is provided at substantially regular intervals with a plurality of such further SMA wires defining a contour substantially perpendicular to the longitudinal axis of the catheter. Preferably, at least one of said further SMA wires is provided at the distal end of the elongated tube, to help maintain the elongated tube in place abutting the proximal extremities of the wings when in activated shape and/or to expose and maximize the opening at the end of the elongated tube facilitating the flow of fluid through the catheter. More preferably for some of these embodiments, the SMA wires are of the kind configured to be removed from the wings of the catheter, for example by pulling on the proximal extremities of the SMA wires protruding at the proximal end of the catheter. Also in preferred embodiments, said closed contour assumes, in retracted shape, a wavy regular shape comprising crenels and recesses, such that each of the SMA wires extending through a channel in the elongated tube passes through the area bordered by one of the crenels. This arrangement allows sufficient space even in retracted shape to provide the walls of the elongated tube with channels for hosting the SMA wires such that the SMA wires can be easily moved along said channels.

In alternative embodiments, the at least one further SMA wire may define other contours, such as a helical shape extending along the elongated tube. Even more preferably, the SMA wires may take the shape of a mesh able to fold and unfold in a so-called “origami” design, wherein the SMA wires form foldable patterns.

[070] The elongated tube is preferably made of soft, collapsible and flexible materials, such that it can be caused to easily transition form an extended shape into a retracted shape and back. Preferably, in extended shape, the elongated tube has a substantially cylindrical shape, with a substantially circular cross-section. In retracted shape, the elongated tube is caused by said further SMA wire(s) to assume a shape with a cross-section having a smaller diameter than the diameter in extended shape. Consequently, the elongated tube is thinner in retracted shape than it is in extended shape, which makes it easier and less traumatic to be guided through the bodily channel. In extended shape, the elongated tube has a larger cross-section diameter than in retracted shape, which ensures that the lumen of the catheter is kept as large as possible, facilitating a better flow of fluids through the elongated tube. Also, assuming said extended shape helps secure the elongated tube in position in the bodily channel during the use of the catheter.

Further features

[071] Further optional features may be provided for the urinary catheter of the invention.

[072] In one embodiment, the urinary catheter further comprises a guiding and/or monitoring device, such as an infrared camera, a camera with fiberoptic light, or a guide wire or a rail wire. Preferably, said guiding or monitoring device is releasably attached to the tip member for guidance of the catheter during insertion and/or removal from the bodily cavity. More preferably said device is an infrared camera or a camera with fiberoptic light, enabling the user to see in advance, for example during insertion of the catheter, possible obstacles and avoid them before any trauma is induced to the patient. In a preferred embodiment, said device can be releasably fitted into a hole performed in the tip member.

[073] In another embodiment, the catheter is further provided with a removable sheath provided onto the whole or part of the catheter, made from a material suitable for preventing bacterial adhesion to the catheter during insertion. When inserting a catheter, it is desirable that the catheter remains sterile and that no bacteria attach thereto during the interval from the opening of its sterile packaging and until the catheter is completely inserted. However, during this interval the catheter is completely uncovered and at risk of coming into contact with bacteria from the surrounding atmosphere and people. Preferably, said removable sheath covers the catheter like a sleeve or a condom that gets removed gradually as the catheter is inserted, so that at all times the portion of the catheter still outside the body is covered with said sheath, thus preventing the risk of contamination. In practice, the person inserting the catheter can push it in by holding the catheter through the sheath, even without wearing gloves, and the sheath gradually folds and gathers at the opening of the bodily channel as the catheter is inserted. After the catheter is fully inserted, the folded sheath can be removed and disposed of. Such a sheath can be provided for and used with similar effects together with any catheter, not only the catheter of the invention.

Method with sheath

[074] Thus, it represents another aspect of the present invention providing a method for inserting a catheter covered with a sheath, comprising the steps: placing the sheath-covered catheter with the distal end at the external opening of a bodily channel; pushing the catheter gradually out of the sheath and into the bodily channel while holding it through the sheath and allowing the sheath to fold and gather at the external opening of the catheter; removing the folded sheath.

[075] In yet another embodiment of the invention, the catheter is provided with means for detecting the presence of microorganisms. After a period of use inside the body of a patient, the lumen of a catheter tends to cover with microorganisms forming a biofilm, which represents a sign of pre infection. It is very important for the health of the patient to be able to timely detect the presence of said biofilm, in order to be able to prevent infections.

[076] Preferably, the inner wall (or lumen wall) of the elongated tube of the catheter is provided with a coating comprising compounds that can signal the presence of microorganisms, such as compounds that change colour and/or become fluorescent in the presence of microorganisms. Preferably, said coating comprises at least one non-toxic dye that changes colour or becomes fluorescent in the presence of living cells, such as a dye chosen from resazurin, fluorescein, triarylmethan dyes (such as Brilliant blue or Christal violet), and/or thiazine dyes (such as methylthioninium chloride, also known as Methiline blue). When in the presence of living cells, said dyes change colour and/or fluorescence, for example because of the change in pH, or because they are transformed by the cells’ metabolism into compounds having a different colour and/or that are fluorescent. [077] In some embodiments, the elongated tube of the catheter is provided with said coating before being inserted into the body of the patient. Alternatively, the elongated tube of the catheter can be provided with said coating after being inserted into the body of the patient, for example by flushing the lumen of the catheter, using a syringe of a like device, with a solution comprising said at least one compound.

Said coating comprising at least one compound that can signal the presence of microorganisms may be provided and used for detecting microorganisms in any type of catheter, not only for the catheter of the present invention.

Method of detecting biofilm

[078] It represents another aspect of the invention the disclosure of a method for detecting the presence of biofilm on a catheter, comprising the steps: a) providing the catheter with compounds that can signal the presence of microorganisms, b) detecting said signal of the presence of microorganisms.

[079] In step a), said signal of the presence of microorganisms may be represented by the change of colour and/or fluorescence of said compounds. Examples of compounds that can signal the presence of microorganisms are those described above.

[080] Step a) may be performed on the catheter before it is inserted into the body of a patient, for example by coating the inner wall of the elongated tube with compounds that can signal the presence of microorganisms during the process of production of said catheter, by usual methods of coating.

[081] Alternatively, step a) may be performed after the insertion and during the use of the catheter, when it is desired to assess whether a biofilm has been formed or not on the inner wall of the elongated tube.

[082] In one embodiment, a solution comprising at least one compound that can signal the presence of microorganisms is flushed inside the lumen of the elongated tube by means of an appropriate device, such as a syringe. Consequently, said at least one compound coats the inner wall of the elongated tube and, when biofilm is present, binds to the microorganisms and can signal their presence. Advantageously for this embodiment, said solution may reach also into the bodily cavity, and said at least one compound may also coat the walls of the bodily cavity, making it possible to detect any biofilm and encrustations thereon by using a camera.

[083] In another embodiment, a strip of litmus paper may be inserted into the elongated tube of the catheter to detect the pH of the medium, in which case said signal will be represented by the change of colour of the litmus. A detected pH of over 7 signals that biofilm is producing.

[084] Step b) of the present method of detecting may be performed, for the compounds that change colour, by observing with the naked eye the colour of the catheter in the visible part thereof or the colour of said litmus paper strip.

[085] Alternatively, for detecting the presence of biofilm in the non-visible areas of the catheter and in the bodily cavity, step b) is performed by introducing a camera through the elongated tube to visualize the biofilm. When the compound(s) used in step a) comprise dyes that become fluorescent in the presence of living cells, such as fluorescein or resazurin, said camera is a blue light camera.

[086] The present method can be used for detecting the presence of biofilm for any type of catheter, not only for the catheter of the present invention.

Kit

[087] In accordance with a further aspect of the present invention, there is provided a kit comprising a catheter as disclosed above together with a manipulator configured to assist the insertion and/or removal of the catheter by means of the elongated tube.

[088] In one embodiment, said manipulator is configured for keeping the wings in their deactivated shape or for changing the shape of the wings from the activated shape into the deactivated shape.

[089] In a preferred embodiment, the manipulator comprises a rod, tube or wire that can be inserted through the elongated tube up to the tip member. Conveniently, the manipulator may further comprise a handle. The rod, tube or wire can maintain the wings in the deactivated shape or it can, by twisting or by pushing against the tip member, cause the wings to change shape from the activated into the deactivated shape. Thus, the manipulator can assist with the change of shape of the wings and with the insertion and/or removal of the catheter. For example, the catheter may be inserted together with the manipulator to ensure that the wings do not transition into the activated shape until the retention mechanism is completely enclosed in the bodily cavity. During removal, after the bodily cavity is irrigated with a cold fluid and the SMA wires have weakened and softened, the manipulator can be introduced into the catheter in order to speed up the process of transitioning into deactivated shape and/or to make sure that the wings are and remain in deactivated shape and there is no risk of trauma during the removal of the catheter.

Methods for inserting

[090] In accordance with a further aspect of the present invention, there is provided a method for inserting the catheter of the invention, comprising the steps: a) inserting the catheter having the wings in deactivated shape through a bodily channel into a bodily cavity; b) allowing the SMA wires to cause the wings to transition into the activated shape at body temperature.

[091] Accordingly, the method of insertion of the catheter of the invention is very simple, time saving and easy to perform, not needing any further steps such as filling a balloon or manipulating an actuation mechanism.

[092] Optionally, before step a), a preparatory step is performed of injecting a chitosan gel or solution through the bodily channel into the bodily cavity, for example with a syringe. The chitosan gel/solution provides an antibacterial medium and lubrication for inserting the catheter, and it may also be used as a natural antibacterial coating for the bodily cavity, such as the bladder. The chitosan can also have healing and therapeutic effects for the bodily cavity such as the bladder.

[093] Optionally, for a catheter covered with a sheath as disclosed above, step a) is performed in accordance with the method for inserting a catheter covered with a sheath according to the invention, namely in substeps ai to a₃: ai) placing the sheath-covered catheter having the wings in deactivated shape with the distal end at the external opening of the bodily channel; a₂) pushing the catheter gradually out of the sheath and into the bodily channel while holding it through the sheath and allowing the sheath to fold and gather at the external opening of the bodily channel; a₃) removing the folded sheath.

[094] In a preferred embodiment, fora catheter of the invention provided with a slidable elongated tube, a further step is performed between step a) and step b) of sliding said elongated tube from a first position to a second position exposing the retention mechanism.

[095] In other preferred embodiments, for a catheter of the invention provided with means for guiding the catheter such as extensions of the wings and/or or extensions of the SMA wires, step a) is performed with the aid of said extensions, by pulling and/or pushing the extensions to facilitate insertion, preferably with the assistance of a guiding device such as a camera.

[096] In yet other preferred embodiment, fora catheter of the invention provided with a removable tip member, a further step is performed between step a) and step b) of removing the tip member.

Method for removing

[097] In accordance with a further aspect of the present invention, there is provided a method for removing the catheter of the invention, comprising the steps: a) cooling the SMA wires; b) allowing the SMA wires to cause the wings of the catheter to transition to the deactivated shape; c) removing the catheter from the bodily cavity through the bodily channel.

[098] In a preferred embodiment, step a) of the method for removing the catheter is performed by injecting a fluid such as water, saline solution or a chitosan solution at room temperature through the catheter into the bodily cavity, for example with a syringe.

As mentioned before, such a method of removal is especially beneficial for the patient, because the irrigation leads to cleaning the bodily cavity such as the bladder and removing of any potential clots or debris. [099] In one embodiment, after step a) and before step c) a further step b’) may be provided: b’) inserting the manipulator of the invention through the catheter and manipulating the wings into the deactivated shape.

[100] The manipulator is useful for speeding up the removal of the catheter and/or for ensuring that the wings are in deactivated shape and there is no risk of trauma during the process.

[101] In another embodiment, for a catheter of the invention provided with a slideable elongated tube, after step a) and before step c) a further step b”) may be provided: b”) sliding the elongated tube from the second position to a first position at least partially covering the retention mechanism.

The sliding of the elongated tube to cover the retention mechanism ensures that the wings are in elongated shape during removal.

[102] In yet another embodiment, for a catheter of the invention provided with removable SMA wires, steps a) and b) are replaced by the step of removing the SMA wires from the retention mechanism of the catheter. The removal of the SMA wires from the retention mechanisms leaves the wings free and flexible, such that they can be safely transitioned into an elongated shape suitable for a safe removal through the bodily channel.

Short description of figures

[103] There are further given, without limiting the generality, some embodiments in connection also with the figures, which represent:

[104] Figure 1a shows a longitudinal section of the distal end of the catheter according to one embodiment of the invention wherein each wing of the retention mechanism has a distal extremity connected to the tip member and a proximal extremity connected to the elongated tube, and an opening is exposed at the end of the elongated tube.

Figure 1b shows a longitudinal section of the distal end of the catheter according to another embodiment of the invention wherein each wing of the retention mechanism has a distal extremity connected to the tip member and a proximal extremity connected to the elongated tube, and the elongated tube is provided with a further portion extending towards the tip member.

Figure 2a shows an overview of the catheter according to one embodiment of the invention wherein each wing of the retention mechanism has a distal extremity connected to the tip member and a proximal extremity connected to the elongated tube.

Figure 2b shows an overview of a manipulator suitable to be used together with the catheter of figure 2a.

Figure 2c shows an overview of the catheter in Figure 2a together with the manipulator of Figure 2b partially inserted therein.

Figure 3a shows a detailed view of the distal end of the catheter in figure 2a.

Figure 3b shows a detailed view of the distal end of the catheter in one embodiment wherein the tip member comprises a neck and a spherical distal extremity.

Figure 3c shows a cross-section through the catheter of figure 3a.

Figure 3d shows cross-sections through the tip member of the catheter in three embodiments: 3d(1) the tip member is a complete bulk solid with the only potential lumens present being the lumens for SMA wires, 3d(2) the tip member has a longitudinal drainage lumen or 3d(3) the tip member has a longitudinal drainage lumen and splits converging to said lumen to allow for the drainage of fluids from the bodily cavity upon insertion of the catheter even without the activation of the SMA wires.

Figure 4a shows an overview of the catheter according to one embodiment of the invention as viewed immediately after insertion, wherein each wing of the retention mechanism has a distal extremity connected to the tip member and a proximal extremity connected to the elongated tube, and the wings are in deactivated shape.

Figure 4b shows an overview of the catheter of Figure 4a with the wings in activated shape. Figure 4c shows an overview of the catheter of Figures 4a and 4b as viewed immediately before removal from the bodily cavity, with the wings in deactivated shape.

Figure 5a shows an overview of an embodiment wherein the catheter of the invention is provided with a slidable elongated tube, the elongated tube being in a first position covering the retention mechanism.

Figure 5b shows the catheter of Figure 5a with the elongated tube being in the second position uncovering the retention mechanism, and the wings of the retention mechanism being in deactivated shape. Figure 5c shows the catheter of Figures 5a and 5b wherein the elongated tube is in the second position uncovering the retention mechanism, and the wings of the retaining mechanism are in activated shape.

Figure 6a shows an overview of an embodiment wherein the tip member of the catheter is removable, and the proximal extremities of the wings are housed during insertion of the catheter inside a recess in the tip member.

Figure 6b shows the catheter of Figure 6a with the wings partially released from the tip member. Figure 6c shows the catheter of Figure 6 with the wings totally released from the tip member and in deactivated shape.

Figure 6d shows the catheter of Figure 6a with the wings totally released from the tip member and in activated shape.

Figure 6e shows the catheter of Figure 6a with the wings in activated shape and the tip member partially removed.

Figure 6f shows the catheter of Figure 6a with the wings in activated shape and the tip member totally removed.

Figure 6g shows the catheter of Figure 6a with the wings in deactivated shape and partially removed from the bodily cavity.

Figure 7a shows an overview of an embodiment wherein the SMA wires are configured to be partially removed, the elongated tube is provided at regular intervals with further SMA wires and the tip member of the catheter is removable. The wings of the catheter are in deactivated shape with the distal extremities hosted in the tip member and provided with SMA wires extending from the wings to the proximal end of the catheter. The further SMA wires and the elongated tube are in retracted shape.

Figure 7aa shows a view from above of one of the further SMA wires in retracted shape. Figure 7b shows the catheter of Figure 7a wherein the further SMA wires and the elongated tube are in extended shape.

Figure 7bb shows a view from above of one of the further SMA wires in extended shape. Figure 7c shows the catheter of Figure 7b with the wings totally released from the tip member and in activated shape.

Figure 7d shows the catheter of Figure 7c with the wings in activated shape and the tip member totally removed. Figure 7e shows the catheter of Figure 7d with the wings in activated shape and the SMA wires removed from the wings and from the distal end of the elongated tube.

Figure 7f shows the catheter of Figure 7e partially removed from the bodily cavity, having the wings partially closed.

Figure 7g shows the catheter of Figure 7f totally removed from the bodily cavity, having the wings totally closed.

Figure 8 shows an overview of the proximal end of the catheter in an embodiment wherein the elongated tube is provided, at its proximal end, with two one-way valves.

Figure 9 shows a cross-section of the elongated tube of the catheter in an embodiment wherein the elongated tube assumes an open state and a closed state, and the wall of the elongated tube has a series of troughs and crests of similar sizes, which interlock in closed state.

[105] Detailed description of the embodiments

[106] Figures 1a and 1b show longitudinal sections of the distal end (120) of the catheter (100) according to two different embodiments of the invention, each comprising an elongated whistle- type tip member (10), a retention mechanism (30) and an elongated tube (20) (partially shown). In these embodiments, the elongated tube (20) is integrally formed with the retention mechanism (30). The retention mechanisms (30) of the embodiments in Figures 1a and 1b each comprise four substantially equal and symmetric Malecot-type wings (31), three of which are depicted in the figures. Each wing (31) has a proximal extremity (32) connected to the elongated tube (20) and a distal extremity (33) connected to the tip member (10). In these embodiments, each wing (31) is provided with an integrated channel hosting a shape memory alloy wire (40) represented as a dotted line, extending from the proximal extremity (32) to the distal extremity (33) of the wings (31). The wires (40) and the wings (31) are shown in their activated shape (42). In these embodiments, in activated shape (42) the wings (31) bend out radially from their longitudinal inactivated shape (41), each taking a curved shape that is approximately semi circular, thus forming the so-called Malecot shape.

[107] In the embodiment shown in Figure 1 a, an opening (22) at the end of the elongated tube (20) is exposed when the wings (31) are in activated shape (42). When the wings (31) split out from the elongated inactivated shape (41) into the curved activated shape (42), they expose among them, near their proximal extremities (32), an opening (22) representing the distal end of the elongated tube (20). Said opening (22) acts as a drainage eyelet which is favorably placed at the position closest to the proximal extremities (32) of the wings (31), meaning that it is placed at the outermost position of the bodily cavity. For example, for a urinary catheter, said opening (22) is maintained at the lowest possible position when in the bladder. This ensures that urine does not get retained in the bladder below the level of the drainage eyelet in a stagnant pool inductive of infections. The Malecot-type wings (31) opening symmetrically in the activated shape (42) further ensure that the opening (22) is stably maintained at said lowest possible position in the bladder throughout the entire time the urinary catheter (100) dwells inside the bladder.

[108] The opening (22) preferably has the largest possible dimension, thus lessening the risk of catheter blockage due to encrustations. Preferably, the opening (22) has the same diameter and the same lumen as the elongated tube (20). Alternatively, as shown in Figure 3b, the dimension of the opening (22) may be reduced if, at the position of the opening (22), channels for hosting the wires (40) are provided in the wall (29) of the elongated tube (20). In this case, the wall (29) of the elongated tube (20) may need to be thicker than when not provided with wires (40). Preferably in order for the opening (22) to still have the largest possible dimension, the wall (29) is thicker only around the wires (40) and only for the least amount necessary.

[109] In the embodiment shown in Figure 1b, the elongated tube (20) is provided with a further portion (24), which extends from the connection of the elongated tube (20) with the proximal extremities (32) of the wings (31) toward the tip member (10). Said further portion (24) is provided with multiple drainage holes (26). Preferably, said multiple drainage holes (26) are placed at different heights around said further portion 24, in order to facilitate drainage and prevent mucus or other debris clogging up the tube. In this embodiment, said further portion has an elongated shape and is placed among the Malecot-type wings (31), such that it gets exposed when the wings (31) transition into the activated shape (42).

[110] Figure 2a shows an overview of the catheter according to one embodiment of the invention wherein each wing of the retention mechanism has a distal extremity connected to the tip member and a proximal extremity connected to the elongated tube. In this embodiment, the urinary catheter (100) has a proximal end (110) and a distal end (120) and comprises a whistle- type tip member (10), an elongated tube (20), and a retention mechanism (30) having four Malecot-type wings (31). The elongated tube (20) is in this embodiment integrally formed with the retention mechanism (30). The wings (31) are shown in activated shape (42), each wing (31) being provided with an SMA wire (40). In this embodiment, the elongated tube (20) is shown to have, at the proximal end, a receiving member (21) adapted to receive a manipulator (200) as shown in Figure 2b. An enhanced view of the distal end (120) comprising the tip member (10) and the retention mechanism (30) is shown in Figure 3a.

[111] Figure 2b shows an overview of a manipulator (200) according to one embodiment of the invention, adapted for manipulating the urinary catheter (100) shown in Figure 2a. In this embodiment, the manipulator (200) is configured for keeping the wings (31) in the deactivated shape (41) or for changing the shape of the wings (31) from the activated shape (42) into the deactivated shape (41). The manipulator (200) comprises in this embodiment a handle (50), and a rod (52) for inserting through the elongated tube (20). The manipulator (200) is adapted to be pushed through the elongated tube (20), passing through the retention mechanism (30) amidst the wings (31), up to the tip member (10). By pushing the rod (52) against the tip member (10), the wings (31) can be maintained in the deactivated shape (41), for instance during insertion of the catheter (100), or they can be caused to change from the activated shape (42) into the deactivated shape (41) for instance during removal of the catheter (100). While pushing against the tip member (10), the manipulator (200) may be further twisted by turning the handle (50). Twisting the manipulator (200) has the further effect of collapsing the wings (31) more tightly in the deactivated shape (41), rendering the retention mechanism more narrow and rigid and thus further facilitating the insertion or removal of the catheter (100). The use of the manipulator (200) represents a safety feature for both insertion and removal of the urinary catheter (100). During insertion, the manipulator (200) ensures that the wings (31) do not prematurely transition into the activated shape (42) no matter how long the insertion process takes. During removal of the catheter (100), the use of the manipulator (200) ensures that the wings (31) are firmly transitioned and maintained in the deactivated shape (41) before starting to pull the catheter (100) out of the bodily cavity, thus avoiding the risk of inducing trauma if the transition was not complete. [112] Figure 2c shows an overview of the urinary catheter (100) according to the embodiment of Figure 2a, together with the manipulator (200) of Figure 2b, which is partially inserted into the catheter (100).

[113] Figure 3a shows a detailed view of the distal end (120) of the catheter of Figure 2a, showing the tip member (10), the retention mechanism (30) and part of the elongated tube (20). The retention mechanism (30) of this embodiment comprises four substantially equal and symmetric Malecot-type wings (31) shown in activated shape (42), each wing (31) having a proximal extremity (32) connected to the elongated tube (20) and a distal extremity (33) connected to the tip member (10). Each wing (31) is provided with a channel for hosting a shape memory alloy wire (40) represented as a dotted line. In this embodiment, a SMA wire (40) extends approximately from the proximal extremity (32) to the distal extremity (33) of each wing (31). An axis T-T is depicted that transversally intersects the catheter (100) at the proximal extremities of the wings (31).

[114] Figure 3b shows a detailed view of the distal end (120) of the catheter (100) in one embodiment wherein the tip member (10) comprises a neck (15) and a distal extremity (17) which is spherical. In this embodiment, the tip member (10) comprises a narrow, flexible neck (15) connected to the retention mechanism (30) such that the SMA wires (40) continue from the wings (31) into the flexible neck (15). The spherical extremity (17) enables an easier passage and the flexible neck (15) is able to bend/flex to facilitate the guidance through the bodily channel into the bodily cavity.

[115] Figure 3c shows a cross-section through the catheter (100) of Figure 3a or 3b, said cross- section being made along the T-T axis depicted in Figures 3a or 3b. In the cross-section depicted in Figure 3c are shown the lumen (28) and the wall (29) of the urinary catheter (100).

In the wall (29) are shown sections of the four channels with the SMA wires (40) of each of the four wings (31). In this embodiment, the wall (29) is thicker in the areas around the wires (40), in order to accommodate the channels and the wires (40). The wall (29) is thicker around the wires (40) so that it can accommodate SMA wires (40) having the necessary diameter and/or position to perform their function of causing the wings (31) to change shape. However, in order to maintain the largest possible dimensions of the lumen (28), the wall (29) is only the least amount thicker necessary and only around the wires (40) not also around its entire circumference.

[116] Figures 3d (1 ), (2) and (3) show cross-sections through the tip member (10) of the catheter (100) in three embodiments wherein four SMA wires (40) extend into the tip member (10).

[117] Figure 3d(1) shows a cross-section through a tip member (10) having a fully closed distal end and no drainage lumen (11). This tip member (10) may be complete bulk solid with the only potential lumens present being the channels for the SMA wires (40). The tip member (10) of Figure 3d(1) allows for resilience during insertion.

[118] Figure 3d(2) shows a cross-section through a tip member (10) having a drainage lumen (11) running longitudinally through the centre of the tip member (10). Said drainage lumen (11) facilitates a fluid communication between the external medium and the lumen of the catheter (100), which enables the passage of fluids from the exterior of the catheter (such as from the bodily cavity) into the lumen of the catheter and vice-versa. Thus, the drainage of fluids from the bodily cavity through the catheter (100) can take place even without the activation of the retention mechanism (30). Moreover, fluids can be administered into the body through the catheter (100) before or without activating the retention mechanism (30).

[119] Figure 3d(3) shows a cross-section through a tip member (10) having a drainage lumen (11) running longitudinally through the centre of the tip member (10), and four splits (19) converging into said drainage lumen (11) to facilitate a more efficient drainage of fluids.

[120] Figure 4a shows an overview of the catheter (100) according to one embodiment of the invention as viewed immediately after insertion through the bodily channel into the bodily cavity. In particular, the catheter of figure 4a can be a urinary catheter, inserted through the urethra into the bladder. Part of the elongated tube (20) is shown in the bodily channel, and the distal end (120) comprising the retention mechanism (30) and the tip member (10) is shown in the bodily cavity. The four Malecot-type wings (31) of the retention mechanism (30) are shown in deactivated shape (41). In this embodiment, the tip member (10) and the retention mechanism (30) with the wings (31) in deactivated shape (41) are narrower and stiffer than the elongated tube (20). This makes it easier and less traumatic to guide the catheter (100) through the bodily channel during insertion, especially in difficult cases (for example, for a urinary catheter, when prostate enlargement areas are constricting the urethra).

[121] Figure 4b shows an overview of the catheter (100) of Figure 4a with the four Malecot-type wings (31) opened in the bodily cavity in activated shape (42). A direction A is defined from above, and a view from direction A shows the tip member (10) connected with the four wings (31). In this embodiment, when the wings (31) are in activated shape (42), the retention mechanism (30) has the Malecot shape. As mentioned before, this equilibrate shape is especially advantageous for a urinary catheter, because it ensures that the retention mechanism (30) remains in the same position at the lower extremity of the bladder for the entire time the urinary catheter (100) is indwelling.

[122] Figure 4c shows an overview of the catheter (100) of Figures 4a and 4b as viewed immediately before removal from the bodily cavity, with the wings (31) in deactivated shape.

[123] Figures 4a, 4b and 4c schematically depict a preferred method for activating and deactivating the retention mechanism (30) of the invention.

The urinary catheter (100) is shown in Figure 4a recently inserted into the bodily cavity. It has the wings (31) in deactivated shape (41) so that it could pass through the bodily channel into the bladder of a patient. The catheter (100) is then allowed to become acclimatized to the body temperature in the bodily cavity, which makes the SMA wires (40) bend outwards and take their activated shape. In turn, the bending of the SMA wires (40) causes the wings (31) to transition into the activated shape (42) as shown in Figure 4b, and to remain stable in this shape for as long as the body temperature is maintained in the bodily cavity.

[124] When it is desired to remove the catheter (100), a cold fluid such as water, saline solution or a chitosan solution is injected, for example with a syringe, through the catheter (100) into the bodily cavity. Preferably, said cold fluid is at room temperature when injected, for example at about 20°C. Flushing the bladder with said cold fluid causes the SMA wires (40) to unbend and revert to their deactivated, elongated shape. This causes the wings (31) to transition to their deactivated shape (41) as shown in Figure 4c, so the retention mechanism (30) reverts to being narrower than the elongated tube (20). Thus, the urinary catheter (100) can be safely and easily removed from the bladder through the urethra. [125] Figures 5a, 5b and 5c show a catheter (100) according to one embodiment of the invention, wherein the catheter (100) is provided with a slidable elongated tube (20). The catheter (100) in this embodiment comprises a whistle-type tip member (10), four wings (31), each wing being provided with an extension (34), and an elongated tube (20) that is slidable between a first position (Figure 5a) and a second position (Figures 5b and 5c). The wings (31) each have a distal extremity (33) abutting the tip member (10) and a proximal extremity (32). The extensions (34), extend from the proximal extremities (32) of each wing to the proximal end (110) of the catheter. The extensions (34) protrude from the elongated tube (20) at the proximal end (110), where they can be manipulated to guide the catheter (100) during insertion and/or removal. In the present embodiment, the wings (31) are provided with SMA wires (40) that extend in the extensions (34).

[126] Figure 5a shows the catheter (100) of this embodiment wherein the elongated tube (20) is in the first position, suitable for the insertion and/or removal of the catheter (100). In first position, the elongated tube (20) of this embodiment houses the four wings (31) and the distal part of the extensions (34), and leaves uncovered the proximal part of the extensions (34). The fact that the elongated tube (20) covers the wings (31) ensures that they are maintained in deactivated shape (41) throughout insertion and/or removal of the catheter (100), with no risk of the wings (31) transitioning to the activated shape (42). In this embodiment, the elongated tube (20) abuts in first position the tip member (10) such that the diameter of the tip member (10) at the area of contact with the elongated tube (20) is at least equal to the diameter of the elongated tube (20) in that area. This allows the elongated tube (20) to push tube against the tip member (10) during insertion.

[127] Figure 5b shows the catheter (100) of the present embodiment wherein the elongated tube (20) is in the second position, and the wings (31) are in deactivated shape (41). Such an arrangement occurs, for example, after the catheter (100) has been inserted within the bodily cavity and the elongated tube (20) has just been slided from the first position to the second position, thus uncovering the wings (31).

[128] Figure 5c shows the catheter (100) of the present embodiment wherein the elongated tube (20) is in the second position and the wings (31) are in activated shape (42). In activated shape (42) the wings (31) abut the tip member (10) at their distal extremities (33) and abut the distal end of the elongated tube (20) at their proximal extremities (32). In this embodiment, the change in shape of the SMA wires (40) causes each wing (31) to bend outwards into a substantially semicircular activated shape (42) such that the wings (31) are maintained in a position wherein their proximal extremities (32) are abutting the distal end of the elongated tube (20). This position ensures that the opening (22) at the end of the elongated tube (20) is exposed and maintained in position to efficiently function for example as a drainage eyelet.

[129] Figures 6a, 6b, 6c, 6d, 6f and 6g show successive views of the distal end of the catheter (100) according to one embodiment of the invention during its insertion and removal from the bodily cavity. In this embodiment, the tip member (10) of the catheter (100) is removable, and the distal extremities (33) of the wings (31) are housed during insertion of the catheter (100) inside a recess (12) in the tip member (10). In the present embodiment, the catheter (100) has four wings (31) provided with SMA wires (40) (SMA wires (40) are depicted only in Figure 6d). The SMA wires (40) cause the wings (31) to open in the activated shape radially, like the petals of a flower, such that, as long as the distal extremities (33) of the wings (31) are at least partially housed inside the recess (12), the wings (31) are not able to transition from the deactivated shape (41) into the activated shape (42). Only after the tip member (10) is removed, the wings (31) will be able to transition to the activated shape (42). Consequently, the tip member (10) of this embodiment prevents the wings (31) from transitioning from the deactivated shape (41) into the activated shape (42) during insertion, ensuring that the wings (31) do not prematurely open, even when the insertion takes a longer time.

[130] Also in this embodiment the tip member (10) and the wings (31) in deactivated shape are narrower and stiffer than the elongated tube (20), facilitating an easy insertion.

[131] The removable tip member (10) has at least the area holding the wings made from an elastic material, thus being able to hold the distal extremities (33) of the wings (31) tightly and securely during insertion and then to assume a narrower shape after releasing the wings (31), so that it can easily pass through the elongated tube (20) when removed. [132] The tip member (10) of this embodiment is provided with a handle (14) such as a wire. The handle (14) is attached to the tip member (10), extends amidst the wings (31), through the elongated tube (20) and outside the catheter (100) such that it can be used by a user to manipulate the tip member (10).

[133] The tip member (10) of the present embodiment is also provided with a hole (16) for fitting a guiding device such as a camera (not represented), enabling the user to see in advance, for example during insertion of the catheter (100), possible obstacles and avoid them before any trauma is induced to the patient.

[134] Figure 6a shows an overview of the present embodiment wherein the catheter (100) has just been inserted into the bodily cavity. The proximal extremities (33) of the wings (31) are housed within the recess (12) of the tip member (10), so the wings (31) are kept in deactivated shape (41).

[135] Figure 6b shows the catheter of Figure 6a wherein the handle (14) is pushed in a direction towards the distal end (120) of the catheter, as shown by the arrow, and the tip member (10) is partially removed. The proximal extremities (33) of the wings (31) are only partially housed inside the recess (12) of the tip member (10). Since the distal extremities (33) are not completely free from the recess (12), the wings (31) remain in the deactivated shape (41).

[136] Figure 6c shows the catheter of Figure 6b wherein the handle (14) continues to be pushed in a direction towards the distal end (120) of the catheter, as shown by the arrow, and the distal extremities (33) are totally removed from the tip member (10). Since the distal extremities (33) are completely free from the recess (12), the wings (31) begin transitioning into activated shape (42). Also, the tip member (10) no longer houses the wings (31), so it tightens elastically, assuming a shape that is narrower that the shape of the tip member (10) when the distal extremities (33) are housed therein, to facilitate the removal of the tip member (10) through the elongated tube (20).

[137] Figure 6d shows the catheter of Figure 6c wherein the tip member (10) remains in place while the wings (31) have transitioned into activated shape (42). [138] Figure 6e shows the catheter of Figure 6d wherein the wings (31) are in activated shape and the handle (14) is pushed in a direction opposite the distal end (120) of the catheter, as shown by the arrow, and the tip member (10) is partially removed.

[139] Figure 6f shows the catheter of Figure 6e wherein the wings (31) are in activated shape and the tip member (10) has been totally removed. An opening (22) is exposed at the distal end of the elongated tube (20) to facilitate the fluid communication to and/or from the bodily cavity through the catheter (100). The catheter (100) safely and securely remains in this position as long as necessary, fulfilling its function.

[140] Figure 6g shows the catheter of Figure 6f partially removed from the bodily cavity. The wings (31) were caused by the SMA wires to transition into deactivated shape (41), so the catheter (100) can be removed by pulling in a direction opposite the distal end (120) as shown by the arrow.

[141] Figures 7a, 7b, 7c, 7d, 7f and 7g show successive views of the distal end of the catheter (100) according to one embodiment of the invention during its insertion and removal from the bodily cavity. In this embodiment, the tip member (10) of the catheter (100) is removable, and the distal extremities (33) of the wings (31) are housed during insertion of the catheter (100) inside a recess (12) in the tip member (10). In this embodiment, the wings (31) are integrally formed with the elongated tube (20). The catheter (100) has four wings (31) provided with SMA wires (40) extending along the elongated tube (20). After they are released from the tip member (10), the wings (31) can be opened by the SMA wires (40) from an elongated deactivated shape (41) into the activated shape (42) like the petals of a flower. In this embodiment, the SMA wires (40) are hosted in hosting channels (not represented) provided in the walls of the wings (31) and continuing in the walls of the elongated tube (20). Said hosting channels are configured to allow the SMA wires (40) to move along the channels when pulled or pushed, such that they can be removed at least from the wings (31). Furthermore, the elongated tube (20) is provided in the present embodiment at substantially regular intervals with a plurality of further SMA wires (44) configured to cause the elongated tube (20) to transition from a retracted shape (23) for insertion of the catheter, to an extended shape (25) for maintaining the elongated tube in position in the bodily channel and/or for maximizing the flow of fluid through the catheter. In this embodiment, each of said further SMA wires (44) is in the shape of a closed contour substantially perpendicular to the longitudinal axis of the elongated tube (20). Each of said further SMA wires (44) is configured to transition from a retracted shape (45) to an extended shape (46) such that the retracted shape (45) has a smaller diameter than the diameter of the extended shape (46). One of said further SMA wires (44) is provided at the distal end of the elongated tube (20), to maximize the opening at the end of the elongated tube (20) for a better fluid communication therethrough.

[142] This embodiment has the further advantage that the SMA wires (40) do not need to be deactivated for the removal of the catheter (100), so even in cases when deactivation is not desired, possible or recommended the catheter may still be safely removed without incurring any trauma to the patient.

[143] Figure 7a shows an overview of the present embodiment wherein the catheter (100) has just been inserted into the bodily cavity. Each of the four wings (31) is provided a SMA wire (40) which extends in the elongated tube (20). The proximal extremities (33) of the wings (31) are housed within the recess (12) of the tip member (10), so the wings (31) are kept in deactivated shape (41). The elongated tube (20) is in retracted shape (23), and also the plurality of further SMA wires (44) are in retracted shape (45).

[144] Figure 7aa shows a view from above of one of said further SMA wires (44) in retracted shape (45), defining a closed contour with a wavy shape. This causes the elongated tube (20) to assume a retracted shape (23) having in cross-section an approximately similar wavy shape.

In this embodiment, said wavy shape (23) is a regular shape comprising four crenels (47) and four recesses (48), such that each of the SMA wires (40) extends through the elongated tube (20) in the area bordered by one of the crenels (47). This arrangement allows sufficient space to provide the walls of the elongated tube (20) with channels for hosting the SMA wires (40) such that the SMA wires (40) can be easily moved along said channels, while at the same time the further SMA wires (44) cause the elongated tube (20) to assume a retracted shape (23) with a smaller diameter than the extended shape (25).

[145] Figure 7b shows the catheter (100) of Figure 7a wherein the elongated tube (20) is in extended shape (25), and also the plurality of further SMA wires (44) are in extended shape (46). The cross-section diameter of the elongated tube (20) in extended shape (25) is bigger than in retracted shape (23). In this embodiment, he further SMA wires (44) have in extended shape (46) a circular shape, such that the elongated tube (20) assumes in extended shape (25) a cylindrical shape, with a substantially circular cross-section, snugly fitting the bodily channel and helping to maximize the flow of fluids therethrough.

[146] Figure 7bb shows a view from above of one of the further SMA wires (44) in extended shape (46).

[147] Figure 7c shows the catheter (100) of Figure 7b wherein the wings (31) are totally released from the tip member (10) and in activated shape (42). The tip member (10) has not yet been removed, so it is represented, together with its handle (14).

[148] Figure 7d shows the catheter of Figure 7c with the tip member (10) totally removed. The wings (31) are in activated shape (42) and the elongated tube (20) is in extended shape (25). The catheter (100) as shown in Figure 7d remains securely in this position in the bodily cavity for as long as needed, until its removal.

[149] Figure 7e shows the catheter of Figure 7d with the SMA wires (40) removed from the wings (31) and from the distal end of the elongated tube (20). In this embodiment, the SMA wires (40) are removed from the wings (31) and from part of the elongated tube (20) by pulling on their proximal extremities (not shown), while the wings (31) are in activated shape (42). This means that the SMA wires (40) of this embodiment do not need to be transitioned to the deactivated shape (41) for the removal of the catheter (100). When no longer provided with SMA wires (40), the wings (31) are no longer forced to remain in open activated shape (42) and they also lose the rigidity conferred by said SMA wires (40) when in activated shape (42). Consequently, the wings (31) become flexible and may elastically revert to and/or easily collapse into an elongated shape when pulled out, ensuring a safe and atraumatic removal of the catheter.

[150] Figure 7f shows the catheter (100) of Figure 7e partially removed from the bodily cavity, having the wings (31) partially closed. In this embodiment, as mentioned before, the wings (31) are configured to be able to open and close radially, like the petals of a flower, each wing (31) following a movement similar to a hand of a clock. In this arrangement, once the SMA wires (40) are removed therefrom, the wings (31) elastically revert to and/or easily collapse into an elongated shape when pulled out, ensuring a safe and atraumatic removal of the catheter (100).

[151] Figure 7g shows the catheter of Figure 7f totally removed from the bodily cavity and with the wings (31) hosted inside the bodily channel during the removal of the catheter (100). The wings (31) are totally closed in a deactivated shape (42). Since the wings are configured to be partially hosted within a tip member (10) that is narrower than the elongated tube (20), they assume a deactivated shape (41) that is also narrower than the elongated tube (20), which helps to easily remove the catheter (100).

[152] Figure 8 shows an embodiment of a catheter wherein the elongated tube (30) is provided, at its proximal end (110), with two one-way valves: one upstream, high pressure one-way valve (60) and one downstream, low pressure one-way valve (62). An in-between section (61) of the elongated tube (30) lays between said upstream one-way valve (60) and said downstream one way valve (62). Said downstream, low pressure one-way valve (62) is provided closer to the proximal end (110) of the elongated tube (30). In this embodiment, the upstream, high pressure valve (60) has a cracking pressure that is higher than the cracking pressure of the downstream, low pressure valve (62). This is represented in the figure with a big arrow showing that the fluid can reach a high pressure upstream the high pressure, one-way valve (60). When the fluid reaches the cracking pressure of the upstream valve (60), it starts to pass the upstream valve

(60) and to flow into the in-between section (61). The presence of fluid in said in-between space

(61) signals the user that the fluid has reached the high-pressure threshold of the upstream valve (60). This signal enables the user to take the appropriate or desired measures (such as applying a bag to the proximal end of the tube, or pinching the valve to drain the fluid) before the fluid in the in-between section (61) reaches the lower pressure threshold of the downstream one-way valve (62). Thus, the present arrangement of two one-way valves allows the catheter to be used without a bag because it gives the user a time interval to become aware of the necessity of draining the fluid and to take the appropriate measures. [153] Figure 9 shows a cross-section of the elongated tube (30) in an embodiment of the catheter (100) wherein the wall of the elongated tube (30) has a series of troughs and crests of similar sizes, which can interlock. One cross-section shows the elongated tube (30) in open state (71) and the other shows the elongated tube (30) in closed state (72). In open state (71) the elongated tube (30) has a circular cross-section with a lumen (28), a wall (29) and a skin (27). In closed state (72) the elongated tube (30) assumes a collapsed, elongated cross-section, wherein said troughs and crests interlock such that almost no lumen (28) remains, ensuring that no backflow of fluid occurs. Figure 9 represents an example of a urinary catheter, wherein said skin (27) and wall (28) are made of silicone, and the wall (28) is made of a softer silicone than the skin (28). For the present embodiment, the diameter of the elongated tube (30) in open state (71) is smaller than the maximum length of the same tube (30) in collapsed, closed state (72). For example, when the diameter in open state (71) is of 5 mm, the maximum length in closed state (72) is of about 7.5 mm. Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.

Claims

1. A catheter (100) having a distal end (120) for insertion through a bodily channel into bodily cavity and a proximal end (110) for manipulating the catheter (100) during insertion and/or removal from said bodily cavity, the catheter (100) comprising: a) a tip member (10) at the distal end (120) of the catheter (100); b) a retention mechanism (30) comprising a plurality of wings (31) each having a distal extremity (33) placed in contact with the tip member (10) and a proximal extremity (32), wherein said wings (31) are provided with shape memory alloy wires (40) configured to cause the wings (31) to transition from a deactivated shape (41) for passing through the channel, guided by the tip member (10) during insertion of the catheter (100), to an activated shape (42) for retention of the wings (31) inside the bodily cavity in order to prevent the removal of the catheter (100); and c) an elongated tube (20) configured to allow circulation of a fluid to and/or from the bodily cavity, wherein, in the activated shape (42), the elongated tube (20) is abutting the proximal extremity (32) of said wings (31).

2. Catheter (100) according to claim 1 , wherein the distal extremities (33) of the wings (31) are releasably connected to the tip member (10).

3. Catheter (100) according to claim 2, wherein the tip member (10) comprises a recess (12) and the distal extremities (33) of the wings (31) are releasably housed inside the recess (12).

4. Catheter (100) according to any one of claims 1 or 3, wherein the tip member (10) is configured to be removed after insertion of the wings (31) into the bodily cavity.

5. Catheter (100) according to claim 1, wherein in the activated shape (42), the distal extremities (33) of the wings (31) are connected to the tip member (10).

6. Catheter (100) according to claim 5, wherein the tip member (10) is provided with at least one drainage lumen (11) configured to allow the passage of fluids from the exterior of the catheter (100) to a lumen (28) of the elongated tube (20) and vice-versa.

7. Catheter (100) according to any preceding claim, wherein removal of the catheter (100) from the bodily cavity takes place in the deactivated shape (41).

8. Catheter (100) according to any preceding claim, wherein the shape memory alloy wires (40) are configured to be withdrawn from the wings (31) and the removal of the catheter (100) from the bodily cavity takes place after withdrawal of the shape memory alloy wires (40) from the wings (31).

9. Catheter (100) according to any preceding claim, wherein the shape memory alloy wires (40) extend towards the proximal end (110) of the catheter (100) to facilitate handling thereof during insertion and/or removal of the catheter (100).

10. Catheter (100) according to any preceding claim, wherein the catheter (100) is provided with at least one further shape memory alloy wire configured to cause the elongated tube (20) to transition from a retracted shape (45) for insertion and/or removal of the catheter (100) to an extended shape (46) for maintaining the elongated tube (20) in position in the bodily cavity and/or for maximizing the flow of fluid through the catheter (100).

11 . Catheter (100) according to any one of the preceding claims, wherein the retention mechanism (30) is integrally formed with the elongated tube (20).

12. Catheter (100) according to any one of the preceding claims, wherein the retention mechanism (30) in deactivated shape (41) has a narrower diameter and is stiffer than the elongated tube (20), thus aiding guidance during insertion of the catheter (100).

13. Catheter (100) according to any one of claims 1 to 10, wherein the elongated tube (20) is slidable between a first position in the deactivated shape (41) at least partially covering the retention mechanism (30), and a second position in the activated shape (42) exposing the retention mechanism (30), the elongated tube (20) abutting the proximal extremities (32) of the wings (31).

14. Catheter (100) according to any preceding claim, wherein the plurality of wings (31) are connected to the elongated tube (20) such that, when in activated shape (42), an opening (22) at the end of the elongated tube (20) is exposed, allowing the drainage of a fluid from the bodily cavity.

15. Catheter (100) according to any one of claims 1 to 12, wherein the elongated tube (20) is provided with a further portion (24) extending from the connection of the elongated tube (20) with the proximal extremities (32) of the wings (31) towards the tip member (10), said further portion (24) being provided with multiple drainage holes (26).

16. Catheter (100) according to any preceding claim, wherein the deactivated shape (41) is achieved when the shape memory alloy wires (40) are below an activation temperature AT, and the activated shape (42) is achieved when the shape memory alloy wires (40) reach the activation temperature AT.

17. Catheter (100) according to claim 16, wherein the activation temperature AT is of about 27°C to about 42°C.

18. Catheter (100) according to any one of the preceding claims, wherein the retention mechanism (30) comprises two, three, four or six wings, preferably four substantially equal and symmetric Malecot-type wings (31).

19. Catheter (100) according to any one of the preceding claims, wherein the wings (31) are provided with channels for hosting the shape memory alloy wires (40).

20. Catheter (100) according to claim 19, wherein the channels for hosting the shape memory alloy wires (40) are integrated into the wings (31).

21 . Catheter (100) according to any one of the preceding claims, wherein the tip member (10) comprises a spherical or an elongated member.

22. Catheter (100) according to any one of the preceding claims, wherein the tip member (10) has a diameter smaller than the diameter of the elongated tube (20).

23. Catheter (100) according to any one of the preceding claims, wherein the shape memory alloy wires (40) are made of the same or different materials, preferably from superelastic materials, such as Nitinol.

24. Catheter (100) according to any one of the preceding claims, wherein the shape memory alloy wires (40) have in the activated shape (42) a rigidity that is higher than their rigidity in the deactivated shape (41).

25. Catheter (100) according to any one of the preceding claims, wherein the shape memory alloy wires (40) have diameters of between about 0.1 to about 0.9 mm, preferably about 0.3 to about 0.6 mm.

26. Catheter (100) according to any one of the preceding claims, wherein the elongated tube (20) and/or the wings (31) are made of materials for reducing bio-fouling and/or encrustation on their surface, such as graphene, chitosan and/or copper products.

27. Catheter (100) according to any one of the preceding claims, wherein the elongated tube (20) of the catheter (100) has the lumen (28) and a wall (29) and is made of materials that are sufficiently soft, flexible and elastic to allow the elongated tube (20) to transition from an open state (71) while the bodily cavity is physiologically in an open state to a closed state (72) while the bodily cavity is physiologically in a closed state.

28. Catheter according to claim 27 wherein the wall (29) of the elongated tube (20) has a series of troughs and crests of similar sizes projecting towards its lumen, which interlock when the elongated tube (20) is in closed state (72).

29. Catheter (100) according to any one of the preceding claims, wherein the proximal end (110) of the catheter (100) is configured to be functionally connected to a peristaltic pump, for drainage or for administering liquids or for irrigation and cleaning of the bodily cavity.

30. Catheter (100) according to claim 29, wherein the proximal end (110) of the catheter (100) is made of a material sufficiently resilient to function as tubing for said peristaltic pump, or wherein a further tube that is sufficiently resilient to function as tubing for said peristaltic pump is introduced into at least part of the elongated tube (20).

31 . Catheter (100) according to any one of the preceding claims, wherein the elongated tube (20) of the catheter (100) is provided with a coating comprising compounds that change colour and/or fluorescence in the presence of microorganisms.

32. Catheter (100) according to any one of the preceding claims, wherein the wings (31) maintain the activated shape (42) at body temperature.

33. Catheter (100) according to any one of the preceding claims, wherein the shape memory alloy wires (40) cause the wings (31) to transition from the activated shape (42) to the deactivated shape (41) upon cooling at a temperature below the activation temperature AT to allow the removal of the catheter (100) from the bodily cavity via the bodily channel.

34. Catheter (100) according to claim 33, wherein said cooling is performed by using water, a saline solution and/or a chitosan solution of about 25°C or less.

35. Catheter (100) according to any one of the preceding claims, wherein a guiding and/or monitoring device is releasably attached to the tip member (10) for guidance of the catheter (100) during insertion and/or removal from the bodily cavity.

36. Catheter (100) according to claim 35, wherein said guiding and/or monitoring device is an infrared camera, a camera with fibreoptic light, preferably fitted into a hole performed in the tip member (10).

37. Catheter (100) according to any one of the preceding claims, further comprising a removable sheath provided onto the whole or part of the tip member (10) and/or the retention mechanism (30), said sheath being made of a material suitable for preventing bacterial adhesion to the catheter (100) during insertion into the bodily cavity.

38. Catheter (100) according to any one of the preceding claims, wherein the elongated tube (20) is further provided, at or near its proximal end, with at least one valve, preferably one-way valve, for the preventing of undesired drainage and/or of the backflow of the fluid.

39. Catheter (100) according to any one of the preceding claims, wherein at least the inner side of the elongated tube (20) is provided, to prevent biofilm or crystallization, with a plurality of biodegradable layers, such as polyelectrolyte coating layers, poly(a-hydroxy ester) or polylactide polymer layers, the layers being degradable or releasable layer-by-layer to wash away the bacteria during the drainage of fluid from the bodily cavity.

40. Catheter (100) according to any one of the preceding claims, wherein the catheter (100) is at least partially coated with chitosan to provide an antimicrobial and lubricating effect.

41 . Kit comprising a catheter (100) according to any one of the preceding claims and a manipulator (200), the manipulator (200) being configured to assist the insertion and/or removal of the catheter (100) by means of the elongated tube (20).

42. Kit according to claim 41 , wherein the manipulator (200) is further configured for keeping the wings (31) in the deactivated shape (41) or for changing the shape of the wings (31) from the activated shape (42) into the deactivated shape (41).