Cannula assembly, system, and method for determining a position of a cannula assembly

Abstract

The invention relates to a cannula assembly for use in regional anaesthesia, comprising: a cannula tube which extends longitudinally between a distal cannula end and a proximal cannula end and has a distal cannula tip; and a cannula hub which is arranged at the proximal cannula end. The cannula tip has increased echogenicity when it is brought into contact with a contrast agent or a saline solution. The invention also relates to a medical system and to a method for determining a position of a cannula tip in an ultrasound image.

Description

[0001] P 62356 WO 27 January 2026

[0002] - 1 - SR / rb

[0003] Cannula arrangement and system and method for determining the position of a cannula tip

[0004] The invention relates to a cannula arrangement, a medical system and a method for determining the position of a cannula tip in an ultrasound image.

[0005] Cannulas, also known as hollow needles, are used for a wide variety of medical applications, primarily for puncturing body tissue and subsequently injecting or aspirating fluids. They can also be used to insert catheters or other invasive devices, with the cannula tube serving as a delivery channel for the device.

[0006] In many medical applications, precise positioning of the cannula within body tissue is of particular importance, for example, when performing a peripheral nerve block, where the anesthesiologist must identify the nerve to be anesthetized and then position the cannula tip as close as possible to the nerve. Cannulas are therefore often positioned using ultrasound imaging techniques, whereby the position of the cannula, especially its tip, is monitored with the aid of an ultrasound image. This requires sufficient visibility of the cannula in the ultrasound image. In other words, the cannula must be sufficiently visible on ultrasound.

[0007] A system known from the prior art is called "OnVision" and is designed to display the position of the cannula tip in an image plane of an ultrasound image. This known system is fully integrated into an underlying ultrasound imaging system.

[0008] The object of the invention is to provide a cannula arrangement, a system, and a method of the type mentioned above that offer advantages over the prior art. In particular, improved visual differentiation between the cannula tube and the cannula tip in the ultrasound image is to be enabled, and especially the ultrasound visibility of the cannula tip is to be improved.

[0009] This problem is solved by providing a cannula arrangement with the features of claim 1, a medical system with the features of claim 6, and a method with the features of claim 8. Advantageous embodiments are specified in the dependent claims. The wording of the claims is incorporated herein by reference.

[0010] The cannula assembly according to the invention is suitable for use in regional anesthesia and comprises a cannula tube and a cannula tip. The cannula tube extends longitudinally between a distal cannula end and a proximal cannula end and has a distal cannula tip. The cannula tip is located at the proximal cannula end. The cannula tip exhibits increased echogenicity compared to the rest of the cannula tube and to conventional cannulas when it comes into contact with a contrast medium or, alternatively, with a saline solution. In other words, when the cannula tip comes into contact with contrast medium or saline solution, it reflects ultrasound waves more strongly than the rest of the cannula tube.

[0011] The cannula arrangement according to the invention allows the user to reliably locate or identify the cannula tip in a corresponding ultrasound image using a generally known ultrasound imaging system. To do this, the user performs the medical procedure, such as a peripheral nerve block, as usual. If the user wishes to orient themselves during the puncture, i.e., when the cannula tip is inside the body, they inject a contrast agent or saline solution in the area of ​​the cannula tip. When the cannula tip comes into contact with the contrast agent or saline solution, the ultrasound waves are reflected more strongly by the cannula tip than by the rest of the cannula tube. This results in a brief flashing or blinking of the cannula tip in the ultrasound image, which makes it easier to determine the position of the cannula tip in the body tissue.Due to the improved ultrasonic visibility of the cannula tip, the cannula arrangement according to the invention also enables improved visual differentiation between the cannula tube and the cannula tip in the ultrasound image.

[0012] In one embodiment of the invention, the cannula tip is coated with a microbubble material. This microbubble material can be lipid-based (e.g., phospholipid), protein-based (e.g., albumin), polymer-based (e.g., polyvinyl alcohol), or glass-based. When in contact with a contrast medium or saline solution, the microbubble material reflects ultrasound waves more effectively than a smooth surface of the rest of the cannula tube, thus further improving the visibility of the cannula tip in an ultrasound image. In particular, the microbubble material can be easily attached to the cannula tip. In another embodiment of the invention, the cannula assembly includes a tube. The tube is arranged at the cannula base and is fluid-conductingly connected to the cannula tube. The tube is designed to deliver the contrast medium, or alternatively the saline solution, towards the cannula tip.This allows the contrast agent to be injected directly into the body tissue via the cannula assembly. As a result, the cannula tip, particularly on the outer side of the cannula tube, comes into direct contact with the contrast agent. This enables rapid and efficient contact between the cannula tip and the contrast agent, and thus particularly efficient identification of the cannula tip in the ultrasound image.

[0013] In one embodiment of the invention, the cannula assembly includes an additional tube. This additional tube is arranged at the cannula base and is fluid-conductingly connected to the cannula tube. The additional tube is designed to deliver further fluids, such as an anesthetic, towards the cannula tip. The two tubes preferably terminate at the cannula base in a common cavity (lumen) of the cannula tube. A valve for metering (controlling) or even shutting off the flow of fluids, particularly the contrast agent and / or the other fluids, can also be provided at the cannula base.

[0014] In one embodiment of the invention, the cannula assembly includes an actuating unit. This unit is designed to manually inject the contrast medium into the body tissue through an opening at the cannula tip. This simplifies handling of the cannula assembly during the puncture. Actuating the unit releases the contrast medium into the tubing, which then flows into the lumen of the cannula tube towards the cannula tip. There, the contrast medium exits the opening into the body tissue. After actuating the unit, the fluid connection between the tubing and the lumen of the cannula tube is closed, preventing further contrast medium from exiting the cannula tip. In an advantageous embodiment, the contrast medium is released when the user activates the unit and holds it in the activated position.When the actuating unit is not in use, the fluid connection is shut off, preventing any further contrast medium from exiting the cannula tip. In an alternative configuration, a defined quantity of contrast medium is injected upon (a single) actuation of the actuating unit.

[0015] The medical system according to the invention is designed to determine the position of a cannula tip in an ultrasound image. For this purpose, the medical system according to the invention comprises a cannula arrangement according to the invention and an ultrasound imaging system. The ultrasound imaging system includes an ultrasound transducer, an evaluation unit, and a display unit. The evaluation unit is designed to generate an ultrasound image based on a received ultrasound signal. The display unit is designed to display the generated ultrasound image. The position of the cannula tip can be determined using the ultrasound image displayed on the display unit.

[0016] Further features and advantages of the medical system will become apparent from the disclosure of the cannula arrangement according to the invention.

[0017] In this embodiment of the invention, the medical system includes a nerve stimulator. The nerve stimulator is designed to generate an electrical impulse and is connected to the cannula assembly. The nerve stimulator allows the cannula assembly to be used to selectively stimulate peripheral nerve fibers.

[0018] The inventive method for determining the position of a cannula tip in an ultrasound image comprises the following steps: creating an ultrasound image using an imaging ultrasound system; injecting contrast medium using a cannula arrangement according to the invention; and determining the position of the cannula tip using the imaging ultrasound system. In this method, the contrast medium emerging or leaking from the cannula tip is clearly visible in the ultrasound image. The precise position of the cannula tip in the body tissue can thus be determined both directly via the cannula tip itself, which is strongly reflected in the ultrasound image, and indirectly via the emerging or leaked contrast medium.

[0019] The ultrasound image is created using an imaging ultrasound system whose function and structure are fundamentally known to the specialist, whereby the cannula tip is to be located in the ultrasound image during the puncture.

[0020] The method according to the invention allows at least an approximate determination of the position of the cannula tip.

[0021] Further advantages and features of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are illustrated with reference to the drawings.

[0022] Fig. 1 shows in a schematic simplified side view an embodiment of a medical system according to the invention with a cannula arrangement according to the invention for determining the position of a cannula tip in body tissue,

[0023] Fig. 2 shows the medical system according to the invention as shown in Fig. 1, wherein a contrast medium is injected by means of the cannula arrangement, and

[0024] Fig. 3 in schematic block representation shows an embodiment of a method according to the invention for determining the position of a cannula tip in an ultrasound image.

[0025] According to Figs. 1 and 2, a medical system 10 according to the invention is set up to determine the position of a cannula tip 3 using an ultrasound image.

[0026] The medical system 10 comprises a cannula arrangement 1 according to the invention and an ultrasound imaging system 20, the function and structure of which are generally known to those skilled in the art. The cannula arrangement 1 according to the invention is used in particular for the puncture of body tissue G for the purpose of subsequent injection and / or aspiration of fluid.

[0027] The ultrasound imaging system 20 comprises an ultrasound transducer 21, an evaluation unit 22, and a display unit 23. The evaluation unit 22 is configured to generate an ultrasound image based on a received ultrasound signal U from the ultrasound transducer 21. The display unit 23 displays the ultrasound image in a known manner.

[0028] The cannula arrangement 1 according to the invention comprises a cannula tube 2 and a cannula attachment 4.

[0029] The cannula tube 2 extends longitudinally between a distal cannula end 2A and a proximal cannula end 2B and has a distal cannula tip 3. In the illustrated embodiment, the distal cannula end 2A forms the cannula tip 3. The cannula tip 3 exhibits increased echogenicity when it comes into contact with a contrast medium K. This means that the cannula tip 3 reflects ultrasound waves U more strongly than the rest of the cannula tube 2. As a result, the cannula tip 3 can be reliably identified in a corresponding ultrasound image, particularly in comparison to the rest of the cannula tube 2.

[0030] The contrast medium K can alternatively be a saline solution. The cannula attachment 4 is attached to the proximal cannula end 2B in a known manner.

[0031] In the embodiment shown, the cannula tip 3 is coated with a microbubble material. Compared to the smooth surface of the section of the cannula tube 2 not coated with the microbubble material, the microbubble material exhibits increased echogenicity and thus improved visibility in the ultrasound image when it comes into contact with the contrast agent K.

[0032] In the embodiment shown, the cannula assembly 1 includes a tube 5. The tube 5 is arranged at the cannula base 4 and is fluid-connected to the cannula tube 2. The tube 5 is designed to deliver the contrast medium K to the cannula tip 3. The contrast medium K is guided through the tube 5 into a lumen of the cannula tube 2 up to the cannula tip 3, where the contrast medium K exits through an opening into the body tissue G and comes into contact with the cannula tip 3, in particular with an outer surface of the cannula tube 2.

[0033] In the embodiment shown, the cannula assembly 1 has an additional tube 6. This additional tube 6 is also arranged at the cannula base 4 and is fluid-connected to the cannula tube 2. The additional tube 6 is designed to deliver further fluids, such as an anesthetic, towards the cannula tip 3. For this purpose, the additional fluid is guided through the additional tube 6 into the lumen of the cannula tube 2 up to the cannula tip 3, where it exits through the opening at the cannula tip 3 into the body tissue G.

[0034] In the embodiment shown, the cannula assembly 1 has an actuating unit not shown in the figures. The actuating unit is designed to inject the contrast agent K into the body tissue G through the opening at the cannula tip 3 by manual actuation. This allows the user to inject the contrast agent K as needed and thereby better locate the cannula tip 3 in the ultrasound image.

[0035] In the embodiment shown, the medical system 10 includes a nerve stimulator 15, whose function and structure are generally known to specialists, for generating an electrical impulse. The nerve stimulator 15 is connected to the cannula assembly 1.

[0036] The inventive method for determining the position of the cannula tip 3 in an ultrasound image can be carried out using the medical system 10 according to Figs. 1 and 2. The inventive method comprises steps S1 to S3 (Fig. 3).

[0037] First, in step S1, an ultrasound image is created using the imaging ultrasound system 20. To determine the position of the cannula tip 3 in the ultrasound image, the user performs the medical procedure, such as a peripheral nerve block, as usual.

[0038] In step S2, contrast medium K is injected during the puncture of body tissue using the cannula arrangement 1 according to the invention. For this purpose, the user manually operates the actuating device as described above, whereby the contrast medium K is injected through the opening at the cannula tip 3.

[0039] Step S3 involves determining the position of the cannula tip 3 using the ultrasound imaging system 20. The contrast agent K emerging from or leaking from the cannula tip 3 is clearly visible in the ultrasound image. When the cannula tip 3 comes into contact with contrast agent K, this causes the cannula tip 3 to briefly illuminate in the ultrasound image, allowing its precise position to be determined immediately. Additionally or alternatively, the user can also determine the position of the cannula tip 3 indirectly via the emerging or leaking contrast agent K.

[0040] The method according to the invention enables the user to orient himself during the puncture, i.e. when the cannula tip 3 is in the body tissue G, and thereby bring the cannula tip 3 as close as possible to the desired target position, for example the nerve.

Claims

Patent claims 1. Cannula arrangement (1) for use in regional anesthesia, comprising: a cannula tube (2) which extends longitudinally between a distal cannula end (2A) and a proximal cannula end (2B) and has a distal cannula tip (3), and a cannula attachment (4) located at the proximal end of the cannula (2B), wherein the cannula tip (3) exhibits increased echogenicity when it is in contact with a contrast medium (K) or a saline solution.

2. Cannula arrangement (1) according to claim 1, wherein the cannula tip (3) is coated with a microbubble material.

3. Cannula arrangement (1) according to claim 1 or 2, wherein the cannula arrangement (1) has a tube (5) which is arranged at the cannula base (4), is fluidly connected to the cannula tube (2) and is configured to deliver the contrast medium (K) or the saline solution to the cannula tip (3).

4. Cannula arrangement (1) according to one of claims 1 to 3, wherein the cannula arrangement (1) has a further tube (6) which is arranged at the cannula attachment (4) and is fluidly connected to the cannula tube (2).

5. Cannula arrangement (1) according to one of claims 1 to 4, wherein the cannula arrangement (1) has an actuating unit which is configured to inject the contrast medium (K) or the saline solution through an opening at the cannula tip (3) by (manual) actuation.

6. Medical system (10) for determining the position of a cannula tip (3) in an ultrasound image, comprising: a cannula arrangement (1) according to any one of claims 1 to 5, and An ultrasound imaging system (20) comprising an ultrasound transducer (21), an evaluation unit (22) configured to generate an ultrasound image based on a received ultrasound signal (U), and a display unit (23) configured to display the ultrasound image.

7. Medical system (10) according to claim 6, wherein a nerve stimulator (15) is provided for generating an electrical impulse, the nerve stimulator (15) being connected to the cannula assembly (1).

8. Method for determining the position of a cannula tip (3) in an ultrasound image, comprising the steps: - Creating an ultrasound image using an ultrasound imaging system (20); - Injecting contrast medium (K) using a cannula arrangement (1) according to any one of claims 1 to 5; and - Determining the position of the cannula tip (3) using the imaging ultrasound system (20), whereby the contrast medium (K) emerging or leaking from the cannula tip (3) is clearly visible in the ultrasound image.

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