WO2001008572A1

WO2001008572A1 - Cannula system for introducing endoscopic tools in a human or animal body

Info

Publication number: WO2001008572A1
Application number: PCT/EP2000/007242
Authority: WO
Inventors: Norbert Heske; Thomas Heske
Original assignee: Norbert Heske; Thomas Heske
Priority date: 1999-07-30
Filing date: 2000-07-27
Publication date: 2001-02-08
Also published as: AU6438800A

Abstract

The invention relates to a cannula system for introducing endoscopic tools in a human or animal body. Said system comprises a hollow cannula (1) which forms a transit channel inside the body after penetrating the skin layers, as well as a mandrel (8) which can be inserted into said hollow cannula (1). The inventive cannula system is characterised in that the hollow cannula (1) has an outer wall (3) with a coaxial screw-type profile surrounding the longitudinal axis of the cannula in a helical manner and in that the mandrel (8) is provided in the form of a straight cylinder allowing the hollow cannula (1) to penetrate the skin layers. The mandrel has an outer profile which matches the inner profile of the hollow cannula (1) so that the mandrel (8) can be precisely inserted in the hollow cannula (1) and is provided with a conical distal tip (10) from which a screw thread (11) widens in a helical manner, whereby the shape, volume and size of said screw thread corresponds to the helical thread (2) of the outer wall (3) of the hollow cannula (1), at the transition between said conical tip (10) and the mandrel (8) in the form of a straight cylinder.

Description

Cannula assembly for introducing endoscopic instruments into a human or animal body

Technical field

The invention relates to a cannula arrangement for introducing endoscopic instruments into a human or animal body with a hollow cannula which forms a through-channel into intracorpular areas after penetration of skin layers, and with a stylet which can be inserted into the hollow cannula.

State of the art

In the field of minimally invasive surgery, a variety of surgical procedures are performed using endoscopic and endosurgical instruments. In order to reach the area to be operated on inside the body with the endoscopic instruments, hollow cannulas are inserted through the skin layers, which serve as working channels for the introduction of endoscopic surgical instruments and the like into the inside of the body.

Previously known hollow cannulas have a cutting tip at their distal end with which they literally cut through the tissue to be penetrated. To introduce known hollow cannulas, for example through the abdominal wall into the interior of the body, this is locally cut with a scalpel knife to create an insertion opening. Through the incision opening within the abdominal wall, the distal, pointed end is now pushed axially into the inside of the body, causing the Cutting tip cuts through vessels, nerves, muscle fibers during insertion. This primarily causes bleeding, which complicates the surgical procedure. Furthermore, due to cutting injuries during the healing process, stronger scarring forms, which lead to increased sensitivity to the weather or other side effects associated with pain. Through the axial insertion of hollow cannulas, for example into the abdominal cavity, the abdominal wall is also subjected to considerable stretching loads, which can be associated with traumatic tissue irritation. The indentations caused by the insertion process of the hollow cannula in the abdominal wall can lead to strong compressions on the internal organs, for example on the intestinal loops, as a result of which internal organs can be severely affected. Bleeding within the inner abdomen can also not be ruled out when using known hollow cannulas with the described surgical techniques into the interior of the body.

In addition, the known hollow cannulas, usually designed with a smooth outer wall, cannot be fixed independently after being introduced into the interior of the body relative to the permeated skin layer. When performing subsequent endoscopic operations, endoscope instruments are used that are passed through the hollow cannula. There are constant relative movements between the hollow cannula and the permeated skin layer, which means that it is also subjected to strong mechanical loads during the operation.

Presentation of the invention

The invention is based on the object of designing a cannula arrangement for introducing endoscopic instruments into a human or animal body with a hollow channel-like cannula which, after penetrating skin layers, forms a through channel into intracorporeal areas in such a way that during the introduction process into the interior of the body and also while performing endoscopic operations on the skin layer to be pierced or mechanical stresses affecting the body cover, which are associated with traumatic tissue irritation, should be decisively reduced. In particular, the disadvantages occurring in the prior art are to be avoided.

The solution to the problem underlying the invention is specified in claim 1. Features which advantageously further develop the inventive idea are the subject of the dependent claims.

According to the invention, a cannula arrangement for introducing endoscopic instruments into a human or animal body is designed with a hollow cannula that forms a through-channel into intracorpular areas after penetration of skin layers, and with a stylet that can be inserted into the hollow cannula in such a way that the hollow cannula has an outer wall with a helical circumferential helical contour coaxial to the cannula longitudinal axis, and that for penetrating the hollow cannula through the skin layers, the stylet is designed as a straight cylindrical stylet that has an outer contour that is adapted to the inner contour of the hollow cannula in such a way that the stylet can be pushed into the hollow cannula with a precise fit and has a distal end region with a tip, which is inscribed by a cone and from the tip of which a helical thread extends from the proximal side.

The combination of a hollow cannula, which has a screw contour that lifts off its surface on the outer wall, and a stylet, which provides a conically tapering tip with screw thread at its distal end, makes it possible to screw the cannula arrangement through skin layers without unduly stressing the skin layers and in particular without cutting the skin layers and the underlying tissue areas.

For the gentle insertion of the hollow cannula into the interior of the body, the straight cylindrical stylet with its screw thread, which in the manner of a corkscrew, essentially dilates the skin layers to the side without them injured by cuts. By rotating the cannula arrangement, the stylet works largely automatically distally into the tissue.

What is essential here is the inventive design of the screw thread on the conical tip of the stylet, which has a self-propelling effect, as is known from a wood screw known per se.

The length of the stylet is such that when the stylet is fully inserted into the hollow cannula, the conically tapering tip of the stylet protrudes completely at the distal end of the cannula. The transition between the hollow cannula and the stylet is preferably without an intermediate gap, so that, with a corresponding penetration process through a skin layer, no tissue parts can get caught between the stylet and the hollow cannula. On the one hand, as already stated above, the outer diameter of the stylet is matched to the inner diameter of the hollow cannula, on the other hand, the outer contour of the cannula in the distal region conforms continuously to the outer circumference of the stylet.

At the proximal end of the hollow cannula, a corresponding recess is provided, into which a pin-like extension engages on the outer wall of the stylet and, with a corresponding rotation in one or the other direction, abuts an abutting edge provided in the recess. As a result, the hollow cannula is also rotated when the stylet is rotated. The pin-like extension on the proximal area of the stylet and the recess on the proximal end of the cannula are designed in such a way that in a direction of rotation in which the screw thread of the stylet and the hollow cannula can be screwed distally into a body cover, the screw thread at the distal transition from the cannula to Mandrin blends seamlessly.

To generate the rotary movement, an electric motor drive is preferably provided, which is designed as a hand-held device and has a rotary shaft, on which the stylet with its proximal end is connected via a plug-and-clamp connection is releasably fixed. The electric motor drive can drive the stylet and the hollow cannula placed on it clockwise or anticlockwise via a corresponding toggle switch.

To introduce the cannula protrusion designed according to the invention, for example through the abdominal wall into the interior of the abdomen, the abdominal wall is preferably locally scratched with a scalpel. By carefully placing the tip of the stylet and simultaneously rotating the cannula arrangement around the longitudinal axis of the cannula, the screw contour on the distal tip of the stylet is able to insert the entire cannula arrangement through the abdominal wall in a self-propelling manner. A particular advantage of the helically designed screw thread during the insertion process is the fact that tissue facing the tip of the mandrel is only displaced laterally while the tip moves forward on the distal side. This causes no or significantly less cuts in the tissue, which would prolong a subsequent healing process.

Medical examinations have shown that during the displacement process described above, no cells are cut through in the sense of being cut through, but only "predetermined breaking points" that are present in cell assemblies are dissolved temporarily, which quickly re-establish their original connection after corresponding reassembly. This is also the reason for a subsequent one rapid healing process, which is without remaining long-lasting wound pain.

The advancement of the stylet and the hollow cannula sitting on the stylet does not take place, as previously, by axial pressure on the cannula arrangement, but only by the rotary movement by means of the electromotive hand-held device, whose rotational speed, which is preferably in the range between 0.1 and 10 revolutions per second, ensures self-propulsion of the cannula arrangement within the tissue. Also, due to the self-propulsion of the cannula arrangement, no adjacent organs are caused by deformation of the abdominal wall compresses or deforms, which is beneficial for performing a gentle operation.

If the tip of the stylet is relatively blunt, so that it is necessary to scratch the abdominal wall with a small scalpel for the piercing process, this has the advantage, however, that tissue areas or even internal organs located in front of the cannula arrangement are pushed away to the side be cut without running the risk of cutting them. This leads to minimal damage to the organs located inside the body, which leads to a faster healing process after the end of the operation.

Brief description of the invention

The invention is described below by way of example without limitation of the general inventive concept using exemplary embodiments with reference to the drawing. Show it:

1a, b cannula-shaped cannula with external thread and stylet with tapered tip with external thread,

2 electric rotating unit,

Fig. 3 stylet with hollow channel as well

Fig. 4 Alternative, hollow-channel-shaped cannula with an external thread and stylet with a tapered tip with an external thread

WAYS OF CARRYING OUT THE INVENTION, INDUSTRIAL APPLICABILITY

In Figure 1a, a hollow cannula 1 is shown, which has a basic shape in the form of a rectilinear hollow cylinder. A screw thread 2 is provided on the outer wall of the hollow cannula 1 and rises from the outer wall 3 of the hollow cannula 1. Tests on skin samples showed that the hollow cannula was formed Teflon enables the hollow cannula to glide smoothly through the skin layer. The distal region of the hollow cannula 1 is cut off in a straight line and ends in a circular cannula edge 4, the distal wall thickness of which is thinned to a minimum. The screw thread 2 ends at the cannula edge 4 immediately in unchanged form. The cannula edge 4 can also have a transition area 4 'in the intermediate area between two screw threads.

At the distal end of the hollow cannula 1, a recess 5 is provided which is delimited by two stop edges 6, 7. A sloping section S is provided between the stop edges 5, 6 in order to increase the distance between the stop edges 6, 7 and thus to provide an improved possibility of completely sinking the stylet into the hollow cannula - as will be described below. A recess V can also be worked into the hollow cannula in the contour of the recess in the immediate vicinity of a stop edge in order to enable a locking, in which pin-like extension snaps into the recess.

Typical dimensions for the inner diameter d of the hollow cannula are between 4 and 25 mm. The path difference h of the screw contour 2 is approximately between 3 and 8 mm. The height a of the screw contour has typical values between 0.5 and 2 mm.

As will be described in the following, a recess 9 engages in the recess 5 and is provided at the proximal end of a stylet 8, which is shown in FIG. 1b. The stylet 8 has a geometry attached to the inner contour of the hollow channel 1 and moreover provides at its distal end a tapered tip 10, on the outer contour of which a screw thread 11 is provided. The cross section of the screw thread preferably has a sawtooth-like geometry 12, which is shown in the detailed illustration according to FIG. 1b. The sawtooth-like structure has a sharp edge 13 with which the skin layer can be cut automatically. In this way it is ensured that the area of skin to be pierced is only cut or dilated to the extent that is so that the hollow cannula can be screwed into the inside of the body with its outer circumference.

Like the hollow cannula, the stylet 8 is preferably made of Teflon in order to improve the sliding properties. A type of implant made of a harder material, for example made of metal, is preferably incorporated at the tip of the stylet 8 for reasons of improved penetration.

The proximal end of the stylet 8 has a bore 16 for plugging onto a rotary shaft 14, a rotating unit 15 (according to FIG. 2), which ensures that the stylet is detachably and firmly plugged onto the rotating unit 15. The rotating unit 15 according to FIG. 2 is provided with a toggle switch 17 which, depending on the tilted position, ensures that the rotary shaft 14 rotates to the right or left. At the end of the rotary unit 15 opposite the rotary shaft 14, a battery compartment which can be closed with a cover 18 is provided, as a result of which the rotary unit 15 can be used as a completely portable tool.

The stylet 8 placed on the rotary shaft 14 is secured with the aid of a snap ring (not shown in the figure) and ensures that the stylet 8 is pulled off the shaft 14 by means of a certain amount of force. The hollow channel 1 is subsequently inserted over the stylet 8 until the pin-like extension 9 rests in the recess 5 on a stop edge 6, 7. By rotating the stylet 8, the hollow cannula 1 is also set in rotation, which bores into the interior of the body through appropriate skin layers.

If the hollow cannula is inserted through the skin layer accordingly, the inner stylet 8 can be removed from the hollow channel. In order to avoid tissue irritation, it is necessary to completely turn back the conical tip 10 projecting distally from the hollow channel 1, which may be in a tissue area over its entire length, into the interior of the hollow cannula. To do this, the surgeon switches on the opposite direction of rotation on the handheld device, whereby the inner stylet is turned back without doing so To move the hollow cannula in the same direction of rotation. The reason for this is the size of the recess 5, ie in particular the spacing of the stop edges 6, 7. When the stylet 8 is turned back, the extension 9 runs from one stop edge 7 to the other stop edge 6, without causing the cannula 1 to rotate.

After the stylet 8 has been completely retracted into the sleeve 1, it can be completely removed by pulling it longitudinally out of the cannula 1, wherein the cannula 1 can serve as a working channel for further endoscopic surgical measures.

Preferred materials for the stylet and sleeve are stainless steel or body-compatible plastics.

A longitudinal section through a stylet 8 is shown in FIG. The stylet 8 is penetrated lengthways by a hollow channel 19. At the distal end region, the hollow channel 19 opens into an opening 20 which is directed distally. On the proximal side, in the exemplary embodiment shown, the hollow channel 19 opens laterally into an opening 21 which is not covered by the hollow cannula which is pushed over the stylet 8. This can also be seen from the fact that the opening 21 is arranged proximal to the pin-like extension 9. In principle, it is also possible to position the opening on the proximal end of the stylet 8.

A rotary coupling 23 in the manner of a rubber sleeve is provided in a gas-tight and rotatable manner around the outer wall of the stylet 8 at the level of the opening 21 in order to ensure a possibility of a gas supply through the hollow channel 19. A supply line is provided on the rubber sleeve 23, which is connected to a gas supply 22, not shown in detail.

On the one hand, the hollow channel 19 is used for insufflation of the inside of the body, and on the other hand, the gas supply is used in particular for monitoring or checking whether the cannula arrangement, for example, during the penetration process into the tissue Has penetrated the abdominal wall and is located in an intracorporeal cavity. For this purpose, a pressure sensor 25, for example in the form of a manometer, is provided in the gas supply line 24, on which the current pressure prevailing in the hollow channel 19 can be read. As long as the stylet 8 is working its way through tissue, the gas in the cavity cannot escape through the distal opening 20. As soon as the stylet 8 penetrates an intracorpolar cavity, the gas escapes, as a result of which the gas pressure drops suddenly. The surgeon can observe this pressure drop on the manometer 25 and knows that, for example, he has completely penetrated the abdominal wall.

4 a and b show an alternative embodiment to the cannula with stylet shown in FIGS. 1 a, b.

In contrast to the embodiment according to FIG. 1 a, the proximal end of the hollow cannula 1 has an internal thread 26, into the thread contour of which the pin extension 9 of the stylet 8 protrudes as soon as the stylet 8 is pushed sufficiently far into the hollow cannula 1 on the proximal side. The thread contour serves the same purpose as the sloping section S and the stop edges 6, 7 in the embodiment according to FIG. 1.

According to FIG. 4b, the stylet 8 has a cutting thread 27 tapering to a distal tip, which, in contrast to the screw thread 11 according to FIG. Fig. 1 b provides a rectilinear, with an incline thread contour 28 which ends in a tip 29 which is not itself arranged centrally to the longitudinal axis of the stylet, but is oriented towards the longitudinal axis of the stylet. This tip formation, which faces the longitudinal axis of the stylet, ensures that the penetration process of the tip of the stylet 8, for example through a skin layer, is easier, i.e. takes place in a self-cutting manner and without exerting a large contact pressure on the skin layer to be penetrated.

The tip 29 can be made from the same material as the stylet 8 itself, for example from Teflon. However, better cutting effects can be achieved if the tip is made of cutting steel or a similar hard material as diamond.

LIST OF REFERENCE NUMBERS

hollow cannula

screw thread

outer wall

cannula edge

Recess, 7 stop edges

mandrin

Pin-like extension 0 Conical tip 1 Screw thread 2 Sawtooth structure 3 Sharp edge 4 Rotation shaft 5 Rotary unit 6 Bore

Toggle switch 8 battery cover 9 hollow channel 0.21 opening

Gas supply 3 rotary coupling

Supply line 5 pressure sensor 6 internal thread

cutting thread

thread contour

top

Claims

claims

1. cannula arrangement for introducing endoscopic instruments into a human or animal body with a hollow cannula (1) which forms a through-channel into intracorpular areas after penetration of skin layers, and with a stylet (8) which can be inserted into the hollow cannula (1), characterized in that the hollow cannula (1) has an outer wall (3) with a helical circumferential helical contour coaxially to the cannula longitudinal axis, and in that the penetration of the hollow cannula (1) through the skin layers of the stylet (8) is designed as a straight-cylindrical stylet that has an external contour has, which is adapted to the inner contour of the hollow cannula (1) such that the stylet (8) can be pushed into the hollow cannula (1) with a precise fit, and has a distal end region with a tip (10), which is inscribed by a cone and A screw thread (11) extends helically from the tip of the proximal side.

2. Cannula arrangement according to claim 1, characterized in that the screw thread (11) has a sawtooth-like cross-section with an oblique to the cannula longitudinal axis and a substantially perpendicular to the cannula longitudinal axis surface section (12, 13).

3. Cannula arrangement according to claim 1 or 2, characterized in that the screw thread (11) at the transition between the conical distal end region and the straight cylindrical region of the stylet successively merges into the straight cylindrical outer contour.

4. cannula arrangement according to one of claims 1 to 3, characterized in that the hollow cannula (1) has a distal and a proximal end, that the distal end is designed as a circular cannula edge (4) and runs in a plane perpendicular to the longitudinal cannula axis, that the screw contour ends directly at the cannula edge (4).

5. cannula arrangement according to one of claims 1 to 4, characterized in that the hollow cannula (1) is designed as a straight hollow cylinder with a constant inner diameter.

6. Cannula arrangement according to claim 4 or 5, characterized in that in the region of the cannula edge (4) the hollow cannula (1) has a decreasing in the direction of the distal end outer diameter with a constant inner diameter, so that the cannula wall thickness with the exception of the screw contour on the Cannula edge reduced to a minimum.

7. cannula arrangement according to one of claims 1 to 6, characterized in that the hollow cannula (1) and / or the stylet (8) is made of plastic or metal material, preferably Teflon.

8. cannula arrangement according to one of claims 1 to 6, characterized in that at least the screw thread (11) in the entire region of the tapered, distal tip (10) of the stylet (8) has a thread contour through which the stylet solely by rotating within undergoes an axial forward movement of biological tissue.

9. cannula arrangement according to one of claims 1 to 8, characterized in that at the proximal end of the stylet (8) an outer contour of the stylet (8) projecting pin-like extension (9) is provided, which in a corresponding recess (5) on the proximal The end of the hollow cannula (1) engages so that when the stylet (8) rotates, the rotary movement can be transmitted to the hollow cannula (1).

10. Cannula arrangement according to one of claims 1 to 9, characterized in that the stylet (8) has a length in which the conical tip (10) of the stylet (8) completely up to the transition to the straight cylindrical region from the hollow cannula (1) projects if the pin-like extension (9) is in engagement with the recess (5) at the proximal end of the hollow cannula (1).

11. Cannula arrangement according to claim 9 or 10, characterized in that the recess (5) at the proximal end of the hollow cannula (1) is large enough so that a freewheeling of the pin-like extension (9) is possible within the recess (5), that the stylet (8) from a completely, with its conical tip (10) from the hollow cannula (1) extended into a largely retracted with its tip into the interior of the hollow cannula (1) position without twisting the hollow cannula (1) ,

12. Cannula arrangement according to one of claims 9 to 11, characterized in that the recess (5) by two spaced apart stop edges (6, 7) is limited, with which the pin-like extension (9) comes into operative connection.

13. Cannula arrangement according to one of claims 1 to 12, characterized in that the stylet (8) has at its proximal end a plug connection flange, via which the stylet (8) with a motor-driven rotating unit (15) is releasably securely connected.

14. Cannula arrangement according to claim 13, characterized in that the rotating unit (15) has a left and right rotation.

15. Cannula arrangement according to one of claims 1 to 14, characterized in that the distal tip of the stylet (8) is sharp-edged or rounded.

16. Cannula arrangement according to one of claims 1 to 15, characterized in that the screw thread (11) at the distal end region of the stylet (8) and the helical circumferential screw contour (2) on the hollow cannula (1) at the transition between stylet (8) and Align the hollow cannula (1) in the state of joint penetration through a skin layer by rotating around the longitudinal cannula matter.

17. Cannula arrangement according to one of claims 1 to 16, characterized in that the stylet (8) has a hollow channel (19) with at least two openings (20, 21), of which one opening (20) in the distal side, conical region ( 10) of the stylet (8) and another opening (21) on the proximal region of the stylet (8) are provided.

18. Cannula arrangement according to claim 17, characterized in that the opening on the proximal side (21) is connected to a gas supply (22) by means of a rotary coupling (23).

19. Cannula arrangement according to claim 18, characterized in that the rotary coupling (23) is a rotatable and gas-tight on the outer wall of the stylet (8) lying sleeve, which is connected via a feed line (24) to the gas supply (22).

20. Cannula arrangement according to claim 18 or 19, characterized in that the gas supply (22) is connected to a pressure sensor (25) which measures the gas pressure in the hollow channel (19) extending through the stylet (8).

21. Cannula arrangement according to one of claims 1 to 20, characterized in that a valve arrangement is provided within the hollow cannula (1) which prevents gas from escaping from the inside of the body to the outside after removal of the stylet (8) from the hollow cannula (1) ,

22. Cannula arrangement according to one of claims 1 to 21, characterized in that at least the distal tip of the stylet is made of a hard material, preferably metal.