FIELD AND BACKGROUND OF THE INVENTION:

The invention relates to a vessel cannulation device.

When perfusion of tissue or an organ is in order, the afferent or efferent vessel, artery or vein (herein referred to as "vessel") is connected to tubing or a syringe. Connecting the vessel is usually done in two ways. Either the vessel is cut and a hollow cannula is inserted in the vessel, or the vessel is not severed but punctured from the side and a cannula is slid inside. The cannula is then fixed to the vessel by winding a piece of suture wire around the vessel at the point where the cannula is inside and the suture wire is tied into a knot. Some cannula systems comprise a solid needle in a hollow cannula and allow the solid needle to be retracted after insertion of the cannula into the vessel: the fluid connection is then achieved. For cannulation specifically where severing of the vessel is not acceptable, there are also tools that comprise a half open puncture needle on an angled handle that, once inserted through the vessel wall allow the insertion of a cannula through the half open needle after which the tool can be removed and the cannula remains. Again, the cannula is fixed to the vessel with a length of suture wire wound around the vessel and tied into a knot. These procedures require the use of at least two hands (mostly three), a separate disposable in the form of the suture wire, access to all around the vessel (for winding the suture wire) and extra tools that need to be disposed of.

SUMMARY OF THE INVENTION:

It is an object of the invention to simplify the procedure of vessel cannulation.

For that purpose, the invention provides a vessel cannulation device comprising a cannula, a needle, a fluid connection, a surrounding body and a clamp, interconnected with each other by means of a main body of the device, wherein:

- the needle has a front needle end and a rear needle end, the front needle end being arranged for puncturing a vessel;

- an axial direction of the device is defined to be parallel to the axial direction of the needle, a forward axial direction of the device is defined by the axial direction of the needle pointing from the rear needle end towards the front needle end, and a backward axial direction of the device is defined to be opposite to said forward axial direction;

- the cannula has a front cannula end pointing in said forward axial direction;

- the needle is coaxially received in the cannula in such manner that the needle is axially slidable back and forth within and relative to the cannula between vessel puncturing positions of the needle and retracted positions of the needle, in which vessel puncturing positions the front needle end projects from the front cannula end for puncturing the vessel, and in which retracted positions the needle is retracted, relative to said vessel puncturing positions, within the cannula in said backward axial direction;

- the fluid connection is arranged for providing fluid communication between the cannula and a tube, when the tube is in fluid communication with said fluid connection;

- in at least one of said puncturing positions the needle is preventing fluid communication via said fluid connection between the cannula and said tube, when the tube is in fluid communication with said fluid connection;

- in at least one of said retracted positions the needle is allowing fluid communication via said fluid connection between the cannula and said tube, when the tube is in fluid communication with said fluid connection;

- said surrounding body is partially surrounding the cannula, over a range in the axial direction of the device, in circumferential direction relative to the cannula with an inter-space between the surrounding body and the cannula;

- said surrounding body has a front edge in said forward axial direction and has an interruption in its surrounding the cannula, which interruption is extending from the front edge in said backward axial direction over at least a subrange of said range in the axial direction of the device; and

- the clamp is arranged for squeezingly clamping the vessel and thereby closing off the vessel.

Such a vessel cannulation device according to the invention requires the use of only two hands and two pairs of tweezers. No extra disposables are required.

Specific embodiments of the invention are set forth in the dependent claims.

In a preferable embodiment, said inter-space, as seen in radial direction relative to the cannula, is narrowing in said backward axial direction of the device.

In another preferable embodiment, said interruption, as seen in circumferential direction relative to the cannula, is narrowing in said backward axial direction of the device.

Furthermore, the invention may be embodied in an assembly of:

- a first vessel cannulation device according to the invention;

- a second vessel cannulation device according to the invention; and

- an interconnecting tube;

wherein the interconnecting tube is in fluid communication both with the fluid connection of the first vessel cannulation device and with the fluid connection of the second vessel cannulation device for providing fluid communication between the cannula of the first vessel cannulation device and the cannula of the second vessel cannulation device.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS:

Further details, aspects and embodiments of the invention will be described, by way of non-limiting example only, with reference to the schematic drawing, in which:

Fig. 1 shows, in perspective view, an example of an embodiment of a vessel cannulation device according to the invention;

Fig. 2 shows the device of Fig. 1 in longitudinal section;

Fig. 3 shows the device of Fig. 1 in side view;

Fig. 4 shows the device of Fig. 1 in another side view being opposite to that of Fig. 3;

Fig. 5 shows the device of Fig. 1 in front view; and

Fig. 6 shows the device of Fig. 1 in bottom view. DETAILED DESCRIPTION:

Figs. 1-6 show a vessel cannulation device Z according to the invention. The device Z comprises a cannula E, a needle F, a fluid connection L (see Fig. 2), a surrounding body P and a clamp G, interconnected with each other by means of a main body C of the device Z. It is remarked that Figs. 1-6 do not show a vessel that may be connected to the device Z.

The main body C may be connected to any perfusion or syringe system via tube B. The tube B may be connected or connectable to the main body C or may be an integral part of the main body C. The main body C comprises grooves D on opposite sides of the body, that allow nesting of the points of tweezers for firm grip, or any other means of holding the device.

The vessel puncturing section of the device consists of a front needle end of a solid needle F. Needle F can also be fitted with a groove on the underside of the needle to allow transportation of fluid from the puncture side out the vessel, where the outflow of fluid can then be seen as a confirmation of successful puncture. Solid needle F runs through cannula E that can be either a separate hollow tube or an integral part of the main body C. Cannula E opens halfway to access to tube B via space L. Solid needle F runs through cannula E and through rubber plug J in the space of main body C. Plug J seals the space around needle F so that no fluid can flow pass J out of the main body C, even when needle F is slid back and forth through cannula E. At its rear needle end, needle F ends in cone A. When cone A is squeezed by tweezers it will slide in the backward axial direction of the device, away from main body C and retract needle F to allow fluid passage through E into space L and tube B.

Vessel clamp G attached to the bottom of main body C allows the clamping of the vessel after puncture. Clamp G comprises space narrowing toward its closed end. Grooves H in the space of clamp G angle toward the puncture front of the body and toward the narrowing of the space. These grooves allow pulling tight of the vessel in the backward axial direction of the device. At release of tension, the vessel will slide over the grooves toward the narrower part of the clamp G and grip itself tight.

The surrounding body P is partially surrounding the cannula E, over a range in the axial direction of the device Z, in circumferential direction relative to the cannula E with an inter-space I between the surrounding body P and the cannula E, wherein a dimension, measured in radial direction relative to the cannula E, of said inter-space I is narrowing in said backward axial direction of the device Z. The surrounding body P has a front edge Q in said forward axial direction and an interruption R (best seen in Fig. 1) in surrounding the cannula, which interruption R is extending from the front edge Q in said backward axial direction over at least a subrange of said range in the axial direction of the device Z. Hence, due to the interruption R, the inter-space I is open at the bottom towards clamp G. This inter-space I will force the vessel wall into the narrowing space when pulled over area K (see Fig. 6) towards and through the clamp G and thus form a liquid tight seal.

The configuration of the device Z can be altered from the depicted longitudinal formation, to a shorter formation, with the tubing B at any angle from the cannula E for cannulation the vessels that are deeply situated inside the operation site. The length of the needle F and the cannula E can be altered to suit the elasticity of the vessel under consideration. The diameters and sizes of needle F, cannula E, main body C and tubing B can also be adjusted to fit any diameter, stiffness, lumen size or available excised free vessel length.

To allow puncturing of a vessel without severing the vessel, either for influx or efflux of fluid, the vessel is first dissected from surrounding tissue allowing free access to the site. Next the vessel is pulled tight with a pair of tweezers, distal to the puncture site. The main body C of the device Z is gripped firmly in one of three opposing grooves D, and needle F is slided through the vessel wall into the lumen of the vessel. The needle F is slid into the vessel until the vessel tissue is in the inter-space I. Then the tweezers holding the distal part of the vessel, pulls and slides the vessel into the space H of clamp G. The cannula E is moved deeper into the vessel by the relative movement of the device Z and the tweezers holding the vessel. The connection is now made. The tweezers holding the vessel can now open and squeeze the cone A (or any other means that slides back needle F) so that the needle F slides backward and opens space L via the pointy end of needle F through cannula E. Fluid can now flow from or toward the vessel and tube B.

The vessel cannulation device according to the invention can be used to cannulate veins, arteries or any duct in the body. The described model is suitable for vessels 2-3 mm thick, but any up or downscaling of the system is possible. The connecting vessel can either be left intact, connected on both sides, or severed distally from the puncture side, as long as enough vessel is distally available for grabbing by tweezers and attachment to the clamp system. Envisioned applications are, but not limited by, organ or tissue perfusion, isolated or in situ, drug administration, tissue or organ washing, (continuous) fluid sampling or (flow, temperature, pressure or constituent) measurement, in situ perfusion rerouting and dye injection. Thus the device according to the invention can be used in organ preservation and/or medication (boosting), local medicine treatment and/or health and function marker measurement. Also envisioned is use in tissue and organ anatomy research, e.g. injections of dyes, isotopes, for the purpose of studying vessel anatomy in living tissue, or waxes or resins for the preservation of the internal vessel structure for studying purposes.

When the vessel is left intact, the cannulation device can be removed, after which coagulation of the puncture site can take place and the anatomy is restored.