DE102009022867B4 - Minimally invasive medical instrument - Google Patents

Abstract

Minimally invasive medical instrument (1), at the operating end (2) of which a first operating element (2a) engages with an enveloping tube (3) and a second operating element (2b; 2b1, 2b2, 18) engages with a core that can be moved through the enveloping tube (3). (4) are arranged to be movable relative to one another, with a force limiter (6) for limiting the force transmitted during the intervention being present on at least one operating element, the minimally invasive medical instrument (1) being designed as an endoluminal medical instrument, and the core (4) having at least one at its end the tool comprises a sling or stone trap, with the enveloping tube (3) not being reinforced and being reinforced at the extracorporeal operating end and the core being made of nitinol, with the force limiter (6) being formed with a preloaded spring (6) which can be compressed when the core (4) is pulled back, the force that is developed on the body's inner enveloping end when the soul is being sealed, according to the spring constant and a permitted displacement path, the first operating element (2a) is connected to the enveloping tube (3) via the spring (6), while the second operating element (2b; 2b1, 2b2, 18) is connected to the core, with a free retainer (14) connected almost to the enveloping tube between the enveloping tube and the first operating element (2a) or and

Description

The present invention relates to what is claimed in the preamble and thus relates to the field of minimally invasive medicine.

In minimally invasive medicine, an intervention is carried out inside a patient's body using instruments that are advanced through a small, natural or, for example, an incision in the body, to the situs, ie the intervention site. High demands are placed on the medical instruments used for this purpose. In addition to the physiological compatibility of the materials used, it is particularly necessary to create very small and flexible instruments in order to be able to penetrate deeper into the interior of the body with the same incision, to reach certain points in the body at all, to enable the simultaneous use of several instruments, etc.

Although the minimally invasive medical instruments should be designed as filigree as possible in order to enable an intervention deep inside the body without any problems and in particular to enable a sufficient flow of detergent around the instrument, the instrument must be easy and safe to use in order to carry out a quick intervention that does not require a long anesthesia without complications even by inexperienced surgeons.

In the field of urology, for example, it has become possible to remove kidney stones and the like using endoscopes. For this purpose, an endoscopic catheter is introduced, which allows optical transmission of images from inside the body and has at least one clear opening through which one or more medical instruments can be inserted and through which the site can be rinsed.

A so-called stone trap basket is then introduced as a medical instrument that can be used endoluminally in this way. This consists of an enveloping tube and a soul that can be moved back and forth in this, at the end of which to be inserted into the body there is a collecting basket formed from wires crossing at least one point. The basket opens when the soul is pushed out of the enveloping tube inside the body. The basket can then be placed around a kidney stone or the like. When the soul is pulled back into the enveloping tube, the wires wrap around the stone and the stone can then be removed together with the enveloping tube through the clear tube of the endoscope.

A problem with conventional minimally invasive stone trapping baskets is that when the core of a stone trapping instrument with the trapped stone is pulled back, so much force is often exerted on the end of the enveloping tube inside the body that the enveloping tube begins to kink, to meander heavily, etc. This is particularly the case in Unacceptable in terms of obstructing the flow of detergent.

Wire-reinforced microcatheters are therefore already known, see for example U.S. Patent 7,507,229 B2 . In this case, a multi-layer catheter is provided for insertion into sites lying inside the body with a covering layer, a reinforcement layer and an inner lining, it being possible for a core or the like to be advanced through the inner region. The flexibility at the distal end, i.e. that end of the medical instrument that is inserted deep inside the body and where the contact between the medical tool and the area to be treated takes place, can be increased by removing the cover or the like, which is also required by physicians Deflectability guaranteed by at least 270° with a narrow radius of curvature. Such instruments are available on the market, but are expensive to manufacture and are undesirably large due to the wire insert in the enveloping tube.

A method for adjusting the stiffness of a microtube and for the production of such tubes is otherwise from U.S. Patent 6,841,214 B1 known.

From the DE 196 93 811 A1 discloses a surgical instrument with a pulling element which is connected to at least one jaw part of a jaw, is guided in an outer tube and is connected to an actuating handle at the other end of the jaw part. The outer tube should be supported against an energy accumulator and, after closing the mouth, be able to be guided in the pulling direction of the pulling element by the actuating handle. The introduction of such instruments directly or via a trocar into the human body is mentioned.

From the DE 27 35 706 A1 discloses a device for manipulating a medical instrument such as a tissue sampling forceps via a control wire slidably disposed within a flexible guide helix. This arrangement is also intended to avoid excessive forces between different elements of the device.

A surgical device with a basket is also from the US 6,264,664 B1 known. Areas of application are the removal of Never rensteinen, gallstones and the like mentioned without much incision. A sleeve made of coextruded material is to be provided, in which a hollow shaft is provided with a through-channel, through which an instrument, in particular an observation instrument, is guided. The center member having the hollow channel is said to be formed of wires twisted together.

The arrangements according to the prior art are too thick and inflexible due to their excessive wall thickness due to the reinforcement, and they also restrict the flushing flow.

From the DE 94 12 371 U1 a probe designed as a stone catcher or the like is known, with a probe hose containing a wire which is coupled at the proximal end to an actuating handle for displacement in the probe hose and which continues at the distal end in a working section (basket) which consists of several in the advanced position of the wire, there is a spring slack travel between the wire and the operating handle, which is preferably formed by a helical spring which is arranged in a rigid end section that can be displaced by the operating handle and is connected to the proximal end of the wire is. In this way, the previously known arrangement seeks to prevent the working sections from damaging, in particular splitting, the front end of the hose. It is mentioned that this can lead to the stone slipping out of the basket due to unfavorable load components. For example, use in the bile duct is mentioned.

This also applies to other areas of application of endoluminal or other minimally invasive medical instruments, such as urology, gastrology, in the field of ear, nose and throat medicine, for arthroscopy and/or bronchoscopy. In addition to stone traps, other foreign body graspers, polyp snares, vascular baskets, etc. should be mentioned. Comparable problems also occur with such devices.

It is desirable to be able to produce a minimally invasive medical instrument at low cost, which is easy to use and allows a problem-free procedure.

The object of the present invention is to provide such a minimally invasive medical instrument.

The solution to this problem is claimed in an independent form. Preferred embodiments can be found in the dependent claims.

A minimally invasive medical instrument according to claim 1 is thus proposed.

The present invention makes optimal use of the fact that it is possible to absorb the forces acting between the enveloping tube and core not directly where they interact, but rather at a point outside the body that is not affected by size problems, i.e. proximal to the surgeon. The knowledge can be used here that despite the very fragile design of minimally invasive medical instruments, there is a not inconsiderable stability against kinks at the end of the intervention because the two parts can move against one another largely without friction. The design with a force limiter to limit the forces transmitted during engagement thus makes reinforcements and the like largely superfluous because there is no longer a risk of buckling between the elements located inside the body.

It is possible with the invention and also preferred if both operating elements are each arranged detachably on the enveloping tube or the core. The detachability of the operating elements is advantageous, for example, if a stone caught in a stone trapping instrument is so large that it cannot be removed through the clear opening of the endoscope with which the minimally invasive medical instrument is being used, and if this is sometimes the case, it cannot be removed either more possible to release the caught stone again. In such a case, the operating elements have to be removed, the endoscope pulled off over the minimally invasive medical instrument remaining inside the body and reinserted next to the minimally invasive medical instrument. Then the stone can be destroyed with a second minimally invasive medical instrument or something similar. The detachability of the controls makes it easier to be able to take such a step quickly and preferably without tools.

According to the invention, the core is made of nitinol and at its end becomes at least one of the tools loop, which includes the stone trap.

The minimally invasive medical instrument of the present invention manages with a less stable enveloping tube than is known in the prior art. This makes it possible to use non-reinforced enveloping tubes and, in particular, to use enveloping tubes made of a very thin material. It is - also therefore - preferred if at least one of Shell or soul at the extracorporeal operating end, ie proximal, is reinforced. The preferred force relief makes it possible, in particular, to use hoses made from less expensive materials, for example Teflon or polyurethane. On the one hand, this reduces the costs of the minimally invasive medical instrument and, on the other hand, makes it possible to produce the minimally invasive medical instrument with a smaller diameter than with other materials.

At least one of the sleeve or core will be reinforced at the extracorporeal operating end, which can be done, for example, by a (capillary) tubular reinforcement crimped around the core and/or a shrink tube arrangement placed around the core or its tubular reinforcement. The reinforcement contributes to the fact that the operating elements can be attached better to the enveloping tube or the core, so that both the assembly and the possibly required separation from the operating elements during an operation are facilitated.

It is further preferred if the first and second operating elements can be fixed relative to one another. This can be done by clamping or a magnetic mechanism, in particular by clamping together. If the elements are not mutually fixable in any desired position, which is clearly preferred, then fixation in at least either the retracted or fully extended position will be desirable. The fixation makes it possible, for example, to safely pull out a stone once it has been caught with the instrument, without releasing it again or freeing it from the collecting basket with rinsing liquid. The clamping is favored by the force limiter of the present invention, since there is no risk of a kink occurring during the setting because the enveloping tube and core (when clamping) still move excessively against one another.

In a particularly preferred variant, the first and second operating elements can be designed to be rotatable in relation to one another, with the core preferably also being able to be rotated relative to the enveloping tube, preferably to the extent that the intervention tool is correspondingly aligned inside the body. The ability to rotate the operating elements alone, even without rotating the interventional tool inside the body, can be advantageous when there are a large number of instruments to be operated in the vicinity of the endoscope or the like, so that the operation of individual instruments is impaired by others.

In a particularly preferred variant, the operating elements are in the form of handles, in particular ring-shaped handles, into which a surgeon can insert his fingers.

The force limiter limits at least those forces that are transmitted to the end of the enveloping tube when the core is pulled back, that is to say when the core moves outwards. However, it should be pointed out that in the same way, additionally and/or alternatively, the forces transmitted forwards from the soul, ie when moving into the interior of the body, can also be limited. This is particularly advantageous when there is a risk of damaging very sensitive tissue. It should also be pointed out that it is also possible to slide the enveloping tube over the core instead of pulling the core back into the enveloping tube; in both cases, without the measures proposed by the invention, the enveloping tube may buckle; However, due to the configuration according to the invention, even with a minimally invasive instrument in which the core (relative to a point in the body, for example) is completely or partially immovable, and instead and/or in addition the enveloping tube is moved and in particular (back) over the core is moved, buckling or the like is prevented. For this reason, no further distinction is made between a movement of the core in the enveloping tube and a movement of the enveloping tube relative to the core.

According to the invention, the force limitation is selected in such a way that the forces that can be transmitted between the core and the casing are still so great that the enveloping tube is not kinked. This ensures that a trapped stone or the like can still be fixed as securely as possible while it is being removed from inside the body.

The force limiter is formed with a spring means, claiming a pretensioned spring that can be compressed by retracting the core. The design of the force limiter with a prestressed spring allows the transmitted force to be limited in a particularly simple manner, namely by selecting the spring constant and the permitted displacement path.

A minimally invasive medical instrument according to the present invention can be used for a large number of different medical applications and, moreover, in both human and veterinary medicine. Any other endoluminal or catheter-based applications, for example, are suitable in addition to the use for urology with stone retrieval baskets. Mention should be made of the urological, gastroenterological, ear and nose Ear medicine, bronchoscopic interventions, arthroscopy and the like.

• 1 eine Prinzipskizze eines minimalinvasiven Medizininstrumentes nach der vorliegenden Erfindung, wobei I und II unterschiedliche Stellungen des Bedienendes veranschaulichen, 2 eine perspektivische Ansicht eines minimalinvasiven Medizininstrumentes gemäß der vorliegenden Erfindung,
• 3 eine Schnittansicht durch das Bedienende eines minimalinvasiven Medizininstrumentes nach der vorliegenden Erfindung,
• 4 eine Schnittansicht entsprechend 3 mit verschiedenen Details in anderer Position des Seelen-Bedienendes,
• 5 ein distales Ende eines erfindungsgemäßen minimalinvasiven Medizininstrumentes mit einem im Steinfangkorb befindlichen Fremdkörper,
• 6 ein minimalinvasives Instrument nach dem Stand der Technik, wobei I und II unterschiedliche Stellungen des Bedienendes veranschaulichen.

The invention is described below only by way of example with reference to the drawing. In this is represented by

• 1 a schematic diagram of a minimally invasive medical instrument according to the present invention, with I and II illustrating different positions of the operator, 2 a perspective view of a minimally invasive medical instrument according to the present invention,
• 3 a sectional view through the operator of a minimally invasive medical instrument according to the present invention,
• 4 a sectional view accordingly 3 with various details in different position of the soul server,
• 5 a distal end of a minimally invasive medical instrument according to the invention with a foreign body in the stone trap,
• 6 a prior art minimally invasive instrument, wherein I and II illustrate different positions of the operator.

To 1 a minimally invasive medical instrument 1, indicated only schematically and generally designated 1, comprises an operating end 2 with a first operating element 2a engaged with a protective tube 3 and a second operating element 2b engaged with a core 4 which can be moved through the protective tube 3 and is made of nitinol. the first and the second operating element 2a, 2b being arranged such that they can be moved back and forth in relation to one another, as indicated by arrow 5. A force limiter 6 is provided on the first operating element 2a in engagement with the enveloping tube 3 and limits the force transmitted from the core 4 to the enveloping tube 3 at the distal end 7 during a minimally invasive medical intervention.

In the exemplary embodiment shown, the first operating element 2a has, by way of example, a penetration ring 2a1 for the ring finger and for the index finger of one hand (compare 2a2), while operating element 2b has, for example, a ring opening for the thumb of a surgeon to pass through, so that by moving these fingers against one another the core 4 can be moved back and forth in the enveloping tube 3; the design with other controls instead of ring openings should be explicitly mentioned; a force limitation is thus also possible, for example, with actuator-operated minimally invasive devices, although it is particularly preferred with manual instruments.

In the present exemplary embodiment, the operating element 2b is directly connected to the core and is thus in engagement with it. The first operating element 2a is firmly connected to the enveloping tube via the spring 6, which is pretensioned and serves as a force limiter, and a connecting piece 8. In the exemplary embodiment shown only schematically here, the operating elements of the enveloping tube or core cannot be detached; how this can be realized on a practical, actually built device will be explained with reference to the 2 until 5 are described below.

A stone trap 9, which can trap stones and the like, for example kidney stones when used in urology, is arranged on the distal actuating end 7 to be inserted into the body of a patient when using the minimally invasive medical instrument.

The enveloping tube 3 is dimensioned in such a way that it can be used endoluminally.

If a kidney stone or the like is caught with the collecting basket 9 using the minimally invasive instrument and the operating element 2b is moved away from the operating element 2a in accordance with the force arrow 10, the core 4 with the trapped stone 12 first moves towards the distal, i.e. inner body, enveloping tube end 3 . As soon as the collecting basket 9 with the stone rests against the end of the enveloping tube 3, force is exerted on the enveloping tube in the axial direction of the enveloping tube, see arrow 11. This in turn leads to a compression of the force limiter 6 through appropriate force transmission, so that when the core 4 is pulled back, the force acting on the enveloping tube 3 is limited. The spring constant of the spring 6 is selected in such a way that the enveloping tube 3 cannot kink.

6 In comparison, shows the situation in a minimally invasive medical instrument according to the prior art without a force limiter 6. If the core is pulled back too far, it is pulled against the end of the enveloping tube with such great force that the end of the enveloping tube buckles or is severely deformed in some other way.

while the in 1 If the exemplary embodiment shown makes it much easier to understand the invention, it will be clear that a practical embodiment of the minimally invasive medical instrument will have a different, advantageous embodiment.

An actual minimally invasive medical instrument 1 is therefore, using largely the same reference numbers, in 2 shown, it should be noted that in a typi rule application of the enveloping tube 3 will have a much greater length and moreover the thickness of the enveloping tube and the core is exaggerated in the figures for reasons of better representation.

In the perspective view of 2 the force limiter 6 is hidden in the tip of the operating element 2. It is therefore referred to below 4 , whereby 4 shows essentially the same section as 3 , however 4b and 4c different ejection position of the core 4 from the enveloping tube 3 is shown. In 3 for reasons of clarity, the insertion of reference symbols has been dispensed with.

In 4 are represented by reference numerals 3 and 4 again the enveloping tube and the core. The spring 6 of the force limiter is accommodated in a spring sleeve 13 which has an opening for a spring holder 14 . The spring holder 14, against which the spring 6 is supported, can slide back and forth in the clear opening.

At the proximal end (on the surgeon's side), the spring sleeve 13 is releasably inserted into a handle cap 15, see reference number 13a, which illustrates the end piece of the spring sleeve 13 latching into a groove in the handle cap 15. A spacer 16 is accommodated in the handle cap 15, which in turn has a clear opening for the core 4 to pass through. The spring sleeve 13, the grip cap 15 and the spacer 16, like the spring holder 14, have clear openings which are coaxial to one another when the parts are arranged correctly.

The core 4 is arranged with a knurled screw 17 on a handle slide 18, which carries two gripping rings 2b1, 2b2 here. While the force limiter 6 and the core 4 as well as the knurled screw 17 can be made of metal, the other parts described above are made of plastic, as is preferred and possible. It should be noted that the embodiments of 1 and 2 differ insofar as the control element for the soul 4 after 1 has a single grip ring for the thumb, while the core has 4 2 is actuated with the slide that has two grip rings.

Furthermore, in the area of the operating end 2, the enveloping tube is initially encased with a reinforcement 3a, which facilitates the placement of the spring holder 14 and stiffens the enveloping tube 3 at the operating end, but this is not critical for the use of the minimally invasive instrument and in particular the flexibility inside the body. Furthermore, the typically very thin nitinol wire that forms the core 4 is crimped at the operator end with a capillary tube for reinforcement.

The embodiment shown allows easy separation of the operating elements from the enveloping tube 3 and core 4 by first loosening the knurled screw 17 and then pulling the spring sleeve 13 out of the handle cap 15 .

The arrangement of the present invention can be used with at most minor changes compared to conventional arrangements and, in particular, makes it possible to ensure adequate security against kinking of the enveloping tube despite the very small enveloping tube diameter and thus very good flushing flow through a given endoluminal lumen.

Claims (10)

Minimally invasive medical device (1), at its operator end (2) a first operating element (2a) in engagement with a protective tube (3) and a second control element (2b; 2b1,2b2,18) in engagement with a core (4) that can be moved through the enveloping tube (3) are mutually movable, wherein there is a force limiter (6) on at least one operating element to limit the force transmitted during the intervention, the minimally invasive medical instrument (1) is designed as an endoluminal medical instrument, and the core (4) at its end comprises at least one of the tools sling or stone trap, wherein the enveloping tube (3) is not reinforced and is reinforced at the extracorporeal operating end and the core is made of nitinol, where the force limiter (6) is formed with a prestressed spring (6) that can be compressed when the core (4) is pulled back, which limits the force that is exerted on the body-inside enveloping sleeve end when the core is closed according to the spring constant and a permitted displacement path, the first operating element (2a) is connected to the enveloping tube (3) via the spring (6), while the second control element (2b; 2b1, 2b2, 18) is connected to the soul, wherein further connected between the enveloping tube and the first operating element (2a) is a free hold (14) almost connected to the enveloping tube or and Minimally invasive medical instrument (1) according to the preceding claim, characterized in that the operating element for the core (4) comprises a slide handle (18) which carries two gripping rings (2b1, 2b2) and on which the core is arranged with a knurled screw. Minimally invasive medical instrument (1) according to one of the preceding claims, characterized in that at least one of the engagement between the first operating element (2a) and the enveloping tube (3) and the engagement between the second operating element (231, 232) and the through the enveloping tube (3 ) movable soul (4) is solvable. Minimally invasive medical instrument (1) according to one of the preceding claims, characterized in that the enveloping tube (3) is a non-reinforced Teflon or polyurethane enveloping tube. Minimally invasive medical instrument (1) according to one of the preceding claims, characterized in that a reinforcement for at least one of the enveloping tube (3) and core (4) is connected to the extracorporeal operating end, which is arranged at least one of around the core (4), with the Soul (4) is crimped or formed as a tubular reinforcement. Minimally invasive medical instrument (1) according to one of the preceding claims, characterized in that the first and second operating elements (2a, 2b) can be fixed relative to one another by clamping and/or a magnetic mechanism in a completely retracted or any or fixed position. Minimally invasive medical instrument (1) according to one of the preceding claims, characterized in that the first and second operating elements (2a, 2b) can be rotated in opposite directions, preferably with rotation of the core (4) relative to the enveloping tube (3), preferably by a Sellinge for alignment or Heinfang sufficient angle of rotation. Minimally invasive medical instrument (1) according to one of the preceding claims, characterized in that the first and the second operating element (2a, 2b) are designed as handles. Minimally invasive medical instrument (1) according to one of the preceding claims , characterized in that the force limiter (6) is designed to limit the force that can be transmitted between the core (4) and the enveloping tube (3), and also non-buckling forces on the enveloping tube (3). Minimally invasive medical instrument (1) according to one of the preceding claims, characterized in that it is designed for an endoluminal, catheter-based or urological or gastroenterological or ear, nose and throat or arthroscopic or bronchoscopic intervention

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