WO2025003390A1

WO2025003390A1 - A laparoscopic applicator having a reservoir and a one-way valve

Info

Publication number: WO2025003390A1
Application number: PCT/EP2024/068232
Authority: WO
Inventors: Lars Tamstrup AXELSSON; Søren CHRISTENSEN
Original assignee: Ferrosan Medical Devices AS
Current assignee: Ferrosan Medical Devices AS
Priority date: 2023-06-30
Filing date: 2024-06-28
Publication date: 2025-01-02
Anticipated expiration: 2025-12-30
Also published as: TW202502276A

Abstract

A laparoscopic applicator for dispensing a substance, e.g. a substance comprising a haemostatic agent, at a selected site by means of a surgical robotic arm, the laparoscopic applicator comprising: a delivery tube; an applicator tip connected to a distal end of the delivery tube, the applicator tip configured for being controllably operated by the robotic arm by a grip section in axial extension of the delivery tube, the grip section having a perimeter transverse to the axis comprising an apex shaped section, such that the grip section is configured for being clamped and spatially manipulated by the robotic arm, a reservoir connected to a proximal end of the delivery tube, the reservoir having a fixed volume, and a one-way valve connected to a proximal end of the reservoir, wherein the one-way valve is configured to prevent flow of the substance through the one-way valve from the reservoir.

Description

A laparoscopic applicator having a reservoir and a one-way valve

Technical field

The present disclosure relates to an applicator, more specifically a laparoscopic applicator for dispensing a medical substance or fluid at a selected site by means of a surgical robotic arm.

Background

Robotic systems are increasingly used in surgery for minimally invasive surgical procedures, to avoid the more invasive traditional open surgery techniques. A robotic system includes a number of robotic arms to which medical devices are attached, and where the robotic arms and the medical devices are controlled and manipulated by the surgeon from a console, e.g. via control devices such as a joystick and foot pedal. Hence, the robotic arms replace the surgeon’s hands at the surgical site, and the surgeon is instead located remotely from the patient and views the surgical site via a display showing a three-dimensional view of the surgical site.

Similarly to traditional open surgery techniques, where an assistant provides the physically present surgeon with the required medical devices, in robotic surgery an assistant is positioned near the robotic arms to provide the arms with the required medical devices. For example, the assistant may replace the medical devices of the robotic arms, and provide medical fluids, either directly as a medical device to the robotic arm, or via an applicator tube introduced into the body via a trocar port.

Surgical haemostatics, as well as other medical fluids and pastes, are traditionally dispensed to a target site by use of a manually operated syringe comprising the paste within the syringe barrel. However, for minimally invasive surgical procedures, the target site is not directly accessible to syringe cannula or syringe tips. Hence, to dispense paste to a target site within a bodily cavity, an elongated applicator tube, which is primed with the paste, is typically introduced into the body via a trocar port. The insertion of the elongated applicator tube occurs at the trocar port.

The invasiveness of minimally invasive surgical procedures using a trocar will depend on the diameter of the trocar and the number of trocars being used. The smaller the diameter, the less invasive is the surgical procedure, and the sooner the patient will recover.

Summary of invention

The present disclosure relates to an applicator, which is particularly suitable for robotic- assisted surgery. Particularly, the present disclosure provides an applicator suitable for insertion into a trocar port and having an applicator tip, where the orientation can be controlled via the inserted applicator’s distal end or the applicator tip. Thus, the applicator may be manipulated and activated via the applicator tip, and hence it is particularly suitable for being manipulated and activated by a robotic arm interacting with the applicator distal end/tip e.g. intra-abdominally during the medical procedure at the surgical site, e.g. wherein the applicator is configured for intra-abdominal delivery of a medical substance. The medical substance may be a medical fluid, a medical paste and/or a medical powder.

A first aspect of the present disclosure relates to a laparoscopic applicator for dispensing or withdrawing a substance, such as a substance comprising a haemostatic agent, at a selected site by means of a surgical robotic arm, the laparoscopic applicator comprising:

- a delivery tube;

- an applicator tip connected to a distal end of the delivery tube, the applicator tip configured for being controllably operated by the robotic arm by a grip section in axial extension of the delivery tube, the grip section having a perimeter transverse to the axis comprising an apex shaped section, such that the grip section is configured for being clamped and spatially manipulated by the robotic arm,

- a reservoir connected to a proximal end of the delivery tube, the reservoir having a fixed volume, and

- optionally a one-way valve connected to a proximal end of the reservoir, wherein the one-way valve is configured to prevent flow of the substance through the oneway valve from the reservoir.

The terms substance, agent or paste may be understood to be interchangeable terms throughout the present application. The target volume of the applicator may be 8 mL, which may correspond to or be a little less than the volume of a standard syringe. The applicator may be primed by a substance like a haemostatic agent by providing the substance from a syringe connected at an opening of the reservoir.

The inner diameter of the delivery tube must on one hand be as small as possible to keep the outer diameter of the applicator below a certain limit, so it is compatible with e.g. a 5 mm trocar, which is considered a small trocar and therefore not really invasive. On the other hand the inner diameter must be sufficiently high, so the force required to prime and dispense the haemostatic agent does not exceed a certain level and it becomes uncomfortable for the user to press the syringe. By positioning the syringe in a pistol grip or power grip suitable for the syringe a higher pressure can be provided, and the inner diameter of the delivery tube can be made even smaller. The syringe may be operated by hand or by a pinch grip without a pistol grip and still the inner diameter of the delivery tube can be made smaller if the substance has a lower viscosity. That the syringe may be operated by hand without a pistol grip has the advantage that the substance can be provided to the surgical site, wherein the substance is provided at a constant rate. To be able to have a flexible delivery tube that can be manipulated by an external robotic arm, the delivery tube will have to be made by a material that will require a thicker wall than if the delivery tube is made of metal. Preferably, the delivery tube comprises a deformable section or a part of the delivery tube is configured to be tension free flexible, so that when an robotic arm moves the delivery tube and let go of the delivery tube, the delivery tube will retain the shape without flexing back to the original shape. The risk that the delivery tube will move out of the sight of the camera during laparoscopy is reduced, if the robotic arm loses grip of the delivery tube. The material of the deformable section or the part of the delivery tube that is configured to be tension free flexible may be a vibrational energy dissipating material selected from the group of: silicone elastomers, butyl rubber, polyurethane, thermoplastic elastomers, polyvinyl chloride, polypropylene and combinations thereof.

Such a delivery tube can also be achieved by the delivery tube having a malleable wire or rod, configured such that the deformable section of the delivery tube may be bent into a desired shape, said shape being approximately maintained upon release of the delivery tube. A certain length of the delivery tube is required for the applicator to be manoeuvrable and be able to access different areas in the patient. However, to provide the same volume, like e.g. 8 mL, the delivery tube has to be made longer when the inner diameter decreases. To solve the problem of a too long delivery tube that is difficult to handle during preparation and when not inserted in the patient, the applicator may have a reservoir with a larger cross-section than the cross-section of the delivery tube. The reservoir is preferably positioned at or near the proximal end of the applicator.

The reservoir should preferably have a fixed volume, so that the substance from the syringe is filling up the reservoir and when the reservoir is full also the delivery tube.

Further, the reservoir establishes a surface area that can be used as grip surface when attaching and detaching the syringe to the applicator. Finally, the surface area can be used to communicate product information (e.g. brand name and product code).

During priming of the applicator, the hemostatic agent flows from the syringe into the applicator.

As the hemostatic agent enters the flexible tube, the pressure is building up and the hemostatic agent is compressed in the rear part of the tube.

When the applicator is fully primed and the user releases the pressure from the syringe piston, the compressed hemostatic agent would push the syringe piston backwards and some hemostatic agent would enter the syringe again. Further, an additional amount of hemostatic agent would flow out from the applicator and contaminate the opening, where the syringe is connected to the reservoir, when detaching the syringe from the applicator.

To avoid backflow of paste into the syringe after priming and outflow of paste when detaching the syringe, a one-way valve like e.g. a duckbill valve, a cross slit valve or a check valve, like a ball check valve, may be mounted at the proximal end of the reservoir.

The valve opens when pressure is applied on the syringe piston and the haemostatic agent starts to flow. When the pressure is released from the syringe piston, the valve will close and prevent haemostatic agent from flowing back out of the reservoir.

A second aspect of the present disclosure relates to a method for dispensing a substance using the applicator according to any of the preceding claims, wherein the method comprises the steps of

- providing a first syringe comprising the substance and a second syringe comprising water or a watery solution like e.g. saline,

- connecting the first syringe to the one-way valve,

- transferring the substance to the applicator through the one-way valve into the reservoir and the delivery tube,

- disconnecting first syringe from the one-way valve,

- connecting the second syringe to the one-way valve,

- transferring the water or the watery solution to the applicator through the one-way valve into the reservoir and the delivery tube for dispensing the substance out of the applicator.

In this way, a substance like a substance having a high viscosity like a paste can easily be dispensed at a site, like a surgical site, without wasting the substance.

Description of drawings

The invention will in the following be described in greater detail with reference to the accompanying drawings.

Figure 1 shows a perspective view of an embodiment of an applicator according to the present disclosure.

Figure 2 shows a syringe for providing paste, powder, liguid, or fluid to the applicator.

Figure 3 shows a perspective and exploded view of an embodiment of the reservoir.

Figure 4 shows a cross-section of an embodiment of the reservoir connected to a oneway valve in the form of a duckbill valve.

Figure 5 shows a cross-section of an embodiment of the reservoir connected to a oneway valve in the form of a ball valve.

Figure 6 shows a cross-section of an embodiment of the reservoir connected to a oneway valve in the form of a duckbill valve. Figure 7 shows a duckbill valve having an elongated structure, wherein a tweezer is acting on the duckbill valve in the elongated direction of the elongated structure. Fig. 8 shows a cross slit valve having two slits forming a cross.

Detailed description

The invention is described below with the help of the accompanying figures. It would be appreciated by the people skilled in the art that the same feature or component of the device are referred with the same reference numeral in different figures.

Applicator for dispensing a substance

For surgical procedures, and particularly minimal invasive surgery like e.g. endoscopic and/or laparoscopic procedures, a substance such as a medical substance such as a surgical haemostatic substance e.g. in the form of a powder, a fluid or a paste, is dispensed to a target site within a body cavity, via an elongated applicator 1 comprising a flexible delivery tube 2 prefilled with the medical fluid/paste/powder, or configured to be filled with the medical fluid/paste/powder during the surgery, as illustrated in Figure 1. The delivery tube may also be referred to as a cannula, and the inner lumen of the tube or cannula may also be referred to as a flow channel for the substance. A distal end or tip 2.2 of the delivery tube or of the applicator may be introduced into the body cavity e.g. via a trocar port, e.g. manually by an assistant. To facilitate the handling and insertion of the delivery tube, which may be flexible, the applicator advantageously comprises an insertion guide such as a rigid sheath 3 configured for inserting the delivery tube into the trocar (not shown). The rigid sheath may for example be in the form of a rigid tubular sheath, which may be positioned around a section of the delivery tube, such as attached to a section of the delivery tube, or forming a coating layer around a section of the outer delivery tube, as illustrated in Figure 1. The insertion guide 3 may comprise a handle 3a so that a user can hold on to and guide the insertion guide 3, and the possibly also the delivery tube 2 inside the insertion guide e.g. through a trocar. Since the insertion guide is rigid, the user can easily push the insertion guide and the delivery tube inside the insertion guide to a position close to the robotic arm. The insertion guide may then be withdrawn so the flexible delivery tube can easily be held and manipulated by an external robotic arm, and moved to the surgical site.

A proximal end 2.1 of the applicator 1 comprises a reservoir 4 for holding a larger amount of the substance per length unit than the delivery tube 2. Figure 2 shows a syringe 11 having a syringe tip 13, wherein a reservoir proximal end 4.1 of the reservoir 4 is configured to receive and connect to the syringe tip 13 in a fluid tight and/or paste tight manner, so that the substance like the paste can be delivered to the applicator 1 without any substance leaking out.

When an applicator 1 is to be used for delivering paste to a surgical site, normally a first syringe 11 comprising the paste is connected to the reservoir 4 of the applicator 1 and fills the delivery tube 2 and the reservoir 4 with the paste. Preferably, the volume of the syringe and the combined volume of the delivery tube 2 and the reservoir 4 are equal so that no paste is wasted. The volume of the syringe may be a little smaller than the combined volume of the delivery tube 2 and the reservoir 4 so that no haemostatic is pressed out of the tip 2.2 of the delivery tube before the applicator is inserted in the trocar and contaminates the trocar.

The applicator 1 may be used in conjunction with a haemostatic substance, agent or paste. The use steps can e.g. be as follows:

The applicator is primed with the haemostatic agent or paste, by connecting a first syringe 11 containing the haemostatic agent to the applicator, where the first syringe may have a male connection like e.g. a male Luer-Lock and the applicator may have a female connection like e.g. a female Luer-Lock, where the male connection or the male Luer-Lock and the male connection or the female Luer-Lock, respectively, are releasably connectable to each other. The user may push the piston rod manually or by a motor, a power grip arrangement, or a syringe pistol with a gearing mechanism etc. pushing on the piston rod until the haemostatic agent has filled the reservoir and the lumen of the delivery tube. The empty first syringe that had the haemostatic agent is detached from the applicator, and a second syringe filled with saline. The second syringe is connected to the applicator and the applicator is inserted into the patient via a trocar. To position the applicator correctly in relation to the surgical site so that the haemostatic agent will be delivered, where the haemostatic agent is needed, the applicator tip may be moved and positioned by a robotic arm (not shown). The insertion guide 3 may be retracted to expose the flexible delivery tube while the surgeon holds the applicator tip with the robotic arm. The applicator can then be moved freely around by the robotic arm. By injecting the saline in the second syringe into the applicator, the haemostatic agent will be pushed out of the applicator onto the surgical site. Figure 3 shows an exploded view of an embodiment of the reservoir 4, a one-way valve 15 in the form of a duckbill valve and a connector 17. A reservoir distal end 4.2 of the reservoir is configured to receive the delivery tube 2 in a fluid tight connection.

According to the disclosure, the reservoir 4 may have a larger cross section than the delivery tube 2, so that the reservoir can hold a larger amount of the substance per length unit than the delivery tube 2, which is shown in Figure 3.

The connector 17 is configured to connect the reservoir 4 and the one-way valve 15 at one end to the syringe 11 at the other end. In one embodiment, the reservoir 4, the one-way valve 15 and the connector 17 are connected in a non-detachable manner, like e.g. by gluing. Preferably, the connector 17 and the syringe 11 are detachably connected to each other in a fluid tight manner, so that the syringe easily can be replaced with another syringe.

The one-way valve 15 will only allow a flow from the proximal end 2.1 of the applicator 1 to the distal end 2.2 of the applicator.

Figure 4 shows a cross section of the reservoir 4, the duckbill valve 15 and the connector 17 of Figure 3 in an assembled view. In the example shown in Figure 4, the applicator has already been filled with a substance 19 and saline 21 has been pressed into the applicator and pushed half of the substance out of the reservoir. Due to the even surfaces of the duckbill valve and the lack of pockets inside the duckbill valve, the duckbill valve can easily be sterilised.

A small pressure from the proximal end (from the right side in Figure 4) will open the duckbill valve so that there may be a flow through the duckbill valve 15 in the direction towards the distal end (the left side in Figure 4).

Due to the viscosity of the substance, priming the applicator with substance from the syringe will create a little over pressure that will cause a leakage of substance out of the reservoir when the syringe is removed. With the one-way valve positioned at the proximal end 2.1 of the applicator there will be no substance leaking out of the primed applicator when the syringe is removed and the contamination can be avoided. In one embodiment, the delivery tube inner cross-section may be less than 30 mm², like less than 20 mm², like less than 14 mm², or like less than 11 mm². If the delivery tube inner cross-section is less than 14 mm², the delivery tube without the insertion guide can be inserted in a 5 mm trocar. If the delivery tube inner cross-section is less than 11 mm², the delivery tube with the insertion guide can be inserted in a 5 mm trocar.

In one embodiment, the delivery tube cross-section may be more than 5 mm², like more than 9 mm². If the delivery tube cross-section is more than 9 mm², the applicator can be primed by haemostatic agent by a syringe operated manually without any additional aid like a motor or a pistol grip.

In one embodiment, the reservoir cross-section may be more than 30 mm², like larger than 50 mm². If the reservoir cross-section is more than 30 mm² the length of the reservoir will have suitable length for giving a good grip for attaching and detaching the syringe to the applicator.

In one embodiment, the reservoir cross-section maybe less than 200 mm², preferably less than 100 mm², preferably less than 80 mm², preferably less than 70 mm².

To reduce waste of the substance, it is advantageous that the substance and the saline are not mixed and that substance closer to the surrounding wall of the reservoir is pushed by the saline together with substance at the centre of the reservoir and with the same speed. This preferred flow is called plug-flow, where velocity of the substance is constant across the cross-section of the delivery tube perpendicular to the axis of the delivery tube.

In one embodiment, the inner cross-section of the reservoir may preferably be less than 70 mm² to maintain the plug-flow.

Figure 5 shows another embodiment, wherein the reservoir 4 is connected to the delivery tube 2, and the one-way valve is a ball valve 23, where a spring 25 presses a ball 27 against a seat 29 for closing the ball valve. In this embodiment, the ball valve 23 comprises a connector 17’ configured to receive a syringe (not shown). In another embodiment, the ball valve 23 and the connector 17’ may be two different units. A pressure pressing on the ball 27 against the spring and away from the seat 29 will open the ball valve, so that the applicator can be primed by substance, like haemostatic agent or paste. Subsequently, saline under pressure from the syringe will open the ball valve and press the substance out of the applicator. The ball may have any other form that together with a corresponding seat will prevent substance from the reservoir to leak out of the applicator. There are other types of one-way valves like e.g. a poppet check valve, a swing check valve, or a cross-slit valve, or a butterfly check valve that could also be used as the one-way valve.

According to the present disclosure, the reservoir distal end 4.2 of the reservoir 4 may have a transition 22 from the reservoir to the delivery tube 2, wherein the transition has a conical shape as shown in Figures 4 and 5. In other embodiments, the transition may have a curved conical shape as shown in Figure 6 or have another smooth transition or smooth shape between the different cross-sections of the reservoir and of the delivery tube. The smooth transition will maintain plug-flow so that saline is not mixing with the haemostatic agent in the contact zone between the saline and the haemostatic agent during the dispense of the haemostatic agent and so that a minimal amount of haemostatic agent is left in the reservoir after use.

Figure 6 shows another embodiment, where a transition 22’ from the reservoir 4 to the delivery tube 2, wherein the transition has a curved conical shape. The curved conical shape will also provide the plug-flow like the conical shape as shown in Figures 4 and 5. The conical shape or the curved conical shape can be combined with any type of one-way valve.

Fig. 7 shows a duckbill valve 15, where pliers 31 are pressing on the duckbill valve 15 in the elongated direction of the elongated structure of the duckbill valve 15.

Figure 8 shows a cross slit valve 41 having two slits 43 forming a cross. Like the duckbill valve, the cross slit valve will only allow paste to pass the cross slit valve in one direction, which in Figure 8 is from the right side to the left side. A small pressure from the right side in Figure 8 will open the cross slit valve so that there may be a flow through the cross slit valve 41 in the direction towards the left side in Figure 8. The cross slit valve is also easy to sterilise. Like the pliers acting on the duckbill valve in Figure 7 for opening the duckbill valve, the cross slit valve can be opened by pliers acting on opposite ends of any of the two slits or by any mechanism, like a button or mechanical button, that pushes the opposite ends of any of the two slits together. The cross slit valve can replace the duckbill valve or any other one-way valve in any of the embodiments presented above and below.

In an embodiment, the pressure needed for opening the one-way valve may be so small that holding the applicator filled with saline vertically with the reservoir at the top and the distal end 2.2 of the applicator 1 at the bottom, the drag force due to the water column will suck air through the one-way valve and into the reservoir and the delivery tube so that the saline can be emptied out of the distal end 2.2 of the applicator and into e.g. a drain.

In another embodiment, the one-way valve may be designed so that the pressure needed for opening the one-way valve may be 100 cm of water, 50 cm of water, or 10 cm of water. If the applicator has been emptied of the substance and filled with saline, and the applicator has been removed from the trocar and the surgical site, then the applicator can easily be emptied of the saline by removing the syringe from the applicator and raising the reservoir 100 cm, or 50 cm or 10 cm, respectively, above the distal end 2.2 of the applicator 1, since the difference in height between the reservoir and the distal end 2.2 of the applicator 1 will provide the necessary pressure to open the one way valve and let air into and saline out of the applicator. Of course the oneway valve may be designed to open at any pressure below 100 cm water, below 50 cm water, or below 10 cm water.

In one embodiment, the applicator may comprise a button that will act on the one-way valve, so by pressing on the button the one-way valve will open. In that case, the saline in the applicator can easily be drained after use by pressing the button, and the oneway valve can be designed so that a higher pressure is needed for opening the oneway valve, and the risk that the applicator is drained of saline accidentally is reduced. The duckbill valve has an elongated structure with a shape similar to a duckbill. The button can act on the duckbill valve by pressing on the duckbill in the elongated direction as shown in Figure 7 forcing the duckbill to open. Two opposite buttons acting in opposite directions in the elongated direction on the duckbill will force the duckbill to open. The button can act on the ball by moving the ball away from the seat. The button can be kept in place in a recess in the wall surrounding the one-way valve, without penetrating the wall. In that way, there is no risk of contamination through an opening, where the button is positioned. The wall surrounding the recess should preferably be a deformable material, so that the button can be moved and act on the one-way valve. Alternatively, the wall of the reservoir surrounding the one-way valve may be made of a deformable material so that by pressing the wall of the reservoir surrounding the oneway valve, the one-way valve, like e.g. the duckbill valve or the ball-valve, will open. No button is necessary.

In one embodiment, the reservoir may have a volume of between 0.5 ml and 3 ml, preferably between 0.7 ml and 2 ml, such as 1 ml. If the total volume of the applicator is 8 mL, the delivery tube will only need to comprise 5 - 7.5 mL, 6 - 7.3 mL, or 7 mL, so that the delivery tube will not be too short, nor too long.

In one embodiment, a first connection of the reservoir to the proximal end of the delivery tube may be opposite a second connection of the reservoir to the one-way valve. If the reservoir have an elongated shape, the first connection and the second connection may be positioned at the opposite short sides of the elongated reservoir. The elongated reservoir may have a part of a toroidal shape like e.g. a quarter of torus, where the two end cross-sections are oriented perpendicular to each other, but would due to the torus shape of the reservoir still be opposite each other. However, two surfaces of a cube that are oriented perpendicular to each other are no considered opposite each other.

By the first connection and the second connection opposite each other, the plug flow can be maintained, and less substance is wasted.

In one embodiment, the first connection and the second connection may be positioned on a symmetry axis through the reservoir so that, if the reservoir has an elongated shape, the first connection and the second connection are positioned in the centre of their respective short sides, and the distance to e.g. a surrounding cylindrical wall is equal in all directions. Such positions of the first connection and the second connection will be ideal for maintaining the plug flow.

Claims

1. A laparoscopic applicator for dispensing a substance, e.g. a substance comprising a haemostatic agent, at a selected site by means of a surgical robotic arm, the laparoscopic applicator comprising:

- a delivery tube;

- a one-way valve connected to a proximal end of the reservoir, wherein the one-way valve is configured to prevent flow of the substance through the one-way valve from the reservoir.

2. The applicator according to any of the preceding claims, wherein the one-way valve is a duckbill valve or a cross slit valve.

3. The applicator according to any of the preceding claims, wherein the reservoir has a volume of between 0.5 ml and 3 ml, preferably between 0.7 ml and 2 ml, such as 1 ml.

4. The applicator according to any of the preceding claims, wherein the reservoir has a reservoir cross-section that is larger than a delivery tube cross-section of the delivery tube.

5. The applicator according to claim 4, wherein the delivery tube cross-section is less than 30 mm², less than 20 mm², less than 14 mm², less than 11 mm², and/or wherein the delivery tube cross-section is more than 5 mm², preferably more than 9 mm², and/or wherein the reservoir cross-section is more than 30 mm², preferably larger than 50 mm², and/or wherein the reservoir cross-section is less than 200 mm², preferably less than 100 mm², preferably less than 80 mm², preferably less than 70 mm².

6. The applicator according to any of the preceding claims, wherein the delivery tube comprises a deformable section or a part of the delivery tube is configured to be tension free flexible.

7. The applicator according to claim 6, wherein the applicator further comprises a malleable wire or rod, configured such that the deformable section of the delivery tube may be bent into a desired shape, said shape being approximately maintained upon release of the delivery tube.

8. The applicator according to claim 6 or 7, wherein the grip section comprises the deformable section.

9. The applicator according to any of the preceding claims, wherein the delivery tube comprises or consists of a vibrational energy dissipating material selected from the group of: silicone elastomers, butyl rubber, polyurethane, thermoplastic elastomers, polyvinyl chloride, polypropylene and combinations thereof.

10. The applicator according to any of the preceding claims, further comprising an insertion guide for supporting the delivery tube, wherein the insertion guide optionally is configured to be slidable along the axial direction of the delivery tube.

11. The applicator according to any of the preceding claims, wherein the applicator has a conical shape or a curved conical shape connecting the reservoir and the delivery tube.

12. The applicator according to any of the preceding claims, wherein a first connection of the reservoir to the proximal end of the delivery tube is opposite a second connection of the reservoir to the one-way valve.

13. The applicator according to claim 12, wherein the first connection and the second connection are positioned on a symmetry axis through the reservoir.

14. A method for dispensing a substance using the applicator according to any of the preceding claims, wherein the method comprises the steps of - providing a first syringe comprising the substance and a second syringe comprising water or a watery solution like e.g. saline,

- connecting the first syringe to the one-way valve,

- disconnecting first syringe from the one-way valve,

- connecting the second syringe to the one-way valve,