DE102015100933A1 - Retraktorstent - Google Patents

Abstract

Disclosed is a stent retractor with a radially expandable, tubular shell, which is divided in the circumferential direction in at least two sections, namely a stiffening portion and an expansion portion with mutually different radial flexibility, which are integrally connected to each other. The thus defined stent-retractor is made by a laser or water cutting process preferably from a tube blank.

Description

The present invention relates to a stent-retractor according to the preamble of patent claim 1 and in particular to a stent which can be used as a retractor and / or as a distractor.

Background of the invention

A distractor is generally a surgical instrument or device for distraction. Distraction is the controlled spreading and possibly permanent attachment of bone in the expansion zone. Distractors are commonly used in trauma surgery, orthopedics and maxillofacial surgery for bone extensional treatment.

A retractor, on the other hand, is a surgical instrument for holding open a surgical field / incision. This instrument is inserted from outside the patient into the surgical field and the spreading elements spaced from each other. As a result, connective and / or muscle tissue is forced apart and thus expanded the surgical field. The necessary extension forces are applied either extracorporeally via optionally mounted on the operating table support arms or intracorporeal by spring and / or support elements, which apply force to each of the spreading elements.

State of the art

For example, the US 6,187,000 B1 discloses a retractor with an expandable distal end. Here, a kind of sheet of stainless metal is rolled into a tube / hopper, wherein the abutting or overlapping foil edges are riveted together. A first, axially end-side rivet here forms a pivoting hinge, whereas a second, axially spaced end rivet is guided in a formed in the film and coiled-film circumferential circumferential backdrop so as to increase the diameter of the film roll sections pivoting about the first rivet or decrease. As a result, a cylinder and a funnel shape can be formed.

From the US 8,372,131 B1 For example, another construction for a stent-retractor of the present type is known. This construction provides for the arrangement of a stent tube or tube, consisting of a processed into a homogeneous wire mesh material preferably having memory properties, wherein the wire mesh inside and / or outside with a fluid-tight membrane, for example made of PTFE is coated. The stent tube is initially mounted on a dilatation set, consisting of a trocar shaft surrounded by a dilatation balloon and having at its distal end a kind of bone anchor in the form of a single centrally located nail or bone screw.

For intracorporeal stent retractor placement, the trocar shaft is inserted into the patient's body and anchored to a patient's bone (e.g., vertebral bone) by the nail or screw. Subsequently, the dilatation balloon is inflated, whereby the stent retractor expands radially, while the surrounding patient tissue radially uniformly apart. Upon release of the bone anchor and withdrawal of the trocar shaft leaving the expanded stent-retractor open, access to the patient is made to perform surgery, preferably with minimally invasive surgical instruments, which are insertable into the channel defined by the stent-retractor.

Finally, out of the WO 2014/022094 A1 In general, a textile structure with separate support elements for forming a retraction known. Thus, a braided tissue formed into a tube is forced radially outward by a type of separate support frame so as to apply a dilation force to the surrounding patient tissue. The scaffold also has a number of rods that penetrate the braided tissue radially outward, which are temporarily anchored in the patient's tissue and thus hold the structure axially in the patient's body.

In the case of the mentioned retractor systems, however, it has been shown that they have a large number of components overall and are therefore relatively expensive to produce. They are therefore not as a disposable article or only partially usable.

In addition, their area of use is limited exclusively to the retractor function. Thus, if surgical procedures are planned which provide, for example, bone distraction, further special distraction instruments are required for this purpose, which must be introduced into the patient via the access channel created by the stent retractor and placed accordingly.

In view of the above-mentioned prior art, it is the object of the present invention to provide a generic stent (retractor) which is suitable as a disposable article.

Furthermore, it is a preferred object of the present invention to extend the field of use of the retractor according to the invention, preferably for additional / alternative use as a distractor.

The above-mentioned objects and objects are achieved according to the invention with a stent retractor / having at least the technical features mentioned in claim 1. Advantageous developments of the stent retractor are the subject of the dependent claims.

Accordingly, in accordance with a first aspect of the present invention, a stent adapted for use as a retractor is proposed. For this purpose, the stent has a radially expandable, tubular wall structure, which is seen in the circumferential direction divided into at least two sections with mutually different (radial) flexibility. In this case, the stent is formed in one piece. Due to the division of the wall structure according to the invention into sections with higher and lower flexibility, the stent firstly has the property of being able to be deformed arbitrarily in the radial direction (eg round, oval, etc.) and nevertheless to maintain sufficient rigidity, tissue in the pressed-apart state to keep. Thus, a minimally invasive approach, for example in the form of a lumbar, thoracic and / or cervical spinal access can be created. Cranial applications are also possible.

The widening sections serve to be able to change the diameter of the stent, whereas the stiffening sections increase the stability of the stent against external radial forces at least in certain radial directions. This makes it possible to use the stent as an alternative or in addition to its retraction function as a distractor instrument, since its in particular on the stiffening sections in principle achievable resistance forces against radially acting Komprimierkräfte may be sufficient to keep bones apart.

By virtue of the preferably one-piece design of the stent, a simple and fast production method, for example by laser or water cutting of metal sheets, is possible. This allows the economic practical implementation of a single-use concept.

Preferably, the wall structure (sheath) of the stent is circumferentially divided into four sections, two of which are designed with substantially equal flexibility as stiffening sections and the two further are designed with substantially equal flexibility as flare sections, for which the two stiffening sections at least in the circumferential direction and preferably also in the axial direction have a higher rigidity than the two expansion sections. By virtue of this development, the stent can be widened uniformly (symmetrically) or even oval, preferably by a surgeon, with simple aids, such as, for example, a dilatation balloon, a speculum or a Langenbeck hook. In particular, for this purpose, the two sections can also be arranged diametrically opposite each with the same flexibility.

According to a preferred, optionally independently claimable embodiment of the present invention, the stiffening portions are formed or provided with receiving and / or attachment structures for additional components. These attachment structures may preferably be formed by punching or cutting out the stiffening sections. In particular, for this purpose, the stiffening portions each consist of a closed sheet metal plate, in which, for example, (through), preferably U-shaped slots are incorporated (cut), whereby tabs or tongues can be formed. If these are bent radially outward, open, notch-shaped undercuts are preferably formed in the axial direction, in which additional (separate) components, such as a sealing foil are hung or inserted / are, which the stent structure (the jacket) inside and / or outside under in Surrounds substantially loose plant and so creates a fluid seal and / or serves as tissue protection.

According to a preferred, optionally independently claimable embodiment of the present invention may be provided as an additional component, a lacing device preferably in the form of a pull rope or laces, which is threaded into the tabs (now preferably designed as loops), such that in a lacing preferably below Shortening the effective length of the pull rope of the stent retractor is radially compressed.

According to a preferred, optionally independently claimable embodiment of the present invention may further be provided as an additional component (in combination with or independently of the above-mentioned components) two bone anchoring elements preferably in the form of nails or distraction screws, which are diametrically opposed to each other (now preferably formed as loops) tabs are axially inserted / are such that they arrange inside or outside of the jacket of the stent. If these bone anchoring elements are used, for example, in two adjacent vertebrae, distraction forces can be applied to the vertebrae with a corresponding radial expansion of the stent. Since the stent according to the invention has the abovementioned stiffening sections, the achievable distraction forces are so great that the bones (vertebrae) remain pushed apart without further (additional) distraction instruments. In that regard, the Stent according to the invention can be used as a retractor and / or distractor system.

According to a preferred embodiment of the invention, which may be claimed independently, it is provided that the widening sections each consist of a number of axially spaced, preferably elastic or plastically deformable expansion elements, which are each preferably formed of a circumferentially extending concertina wire. As a result, the wall structure of the stent, in particular in the area of the widening sections, can be produced by punching or cutting, preferably laser or water cutting, for example from a (closed) tube profile, which can subsequently also be deburred. The production is thus simple and inexpensive and therefore suitable overall for "single-use" products.

According to a preferred embodiment of the invention, which may be claimed independently, it is further provided that the stent is divided axially into a number of (circular) segments each having circumferentially spaced internal stiffening and widening portions as described above are coupled to each other via axial connecting elements / webs with preferably higher rigidity, which further preferably form predetermined breaking points for segment-wise length reduction. This configuration ensures that the stent essentially only expands radially under an internal pressure load. In addition, the stent can be easily adapted in its length according to its intended site of use on the patient's body.

The invention will be explained below with reference to preferred embodiments with reference to the accompanying figures

Show it

1 the development of a wall structure of a stent according to a first preferred embodiment of the present invention,

2a C the tubular or tubular stent according to the invention 1 as a semi-finished product and equipped with a separate fluid sealing wall,

3 the tubular or tubular stent according to the invention is equipped with a separate lacing device as an alternative or in addition to the fluid sealing wall,

4a B the tubular or tubular stent according to the invention, equipped with separate bone anchoring elements arranged on the stent on the outside, alternatively or in addition to the fluid sealing wall and / or lacing device,

5 the tubular or tubular stent according to the invention, equipped with separate bone anchoring elements arranged on the inside of the stent, as an alternative or in addition to the fluid sealing wall and / or lacing device,

6 the development of a wall structure of a stent according to a second preferred embodiment of the present invention,

7 the tubular or tubular stent according to the invention according to 6 as a semi-finished product,

8th the tubular or tubular stent according to the invention according to 6 in which the stiffening sections / elements are equipped or designed with selected or selectable functionalities,

9 the tubular or tubular stent according to the invention according to 6 with sections widened diameter to achieve a sectional funnel shape, especially in a range with axially elongated stiffening sections / elements and

10a -B two functional sketches for the optical representation of a possible stent application by means of a pedicle screw system already known from the prior art.

According to the 1 and 2a is the wall structure of a stent (retractor distractor) 1 According to a first preferred embodiment of the present invention seen in the circumferential direction of two peripheral portions with low rigidity 2 (hereinafter referred to as expansion portions / elements) and two peripheral portions with comparatively high rigidity 4 (hereinafter referred to as stiffening sections / elements), which are arranged alternately in the circumferential direction to each other and in the axial direction linear.

In principle, the stent according to the invention has 1 a tubular or tubular shape, wherein the peripheral portions with mutually equal / similar stiffness diametrically opposite each other. The stent 1 is also formed in one piece, ie the individual peripheral sections are stoffeinstückig interconnected.

The comparatively thin-walled stent tube (about 0.5 to 1.5 mm) is preferably subdivided into the aforementioned peripheral sections by laser beam cutting or water jet cutting. It should be noted, however, that others Machining techniques such as punching or milling for the production of the wall structure described below can be used. Depending on the need and intended use / location, the initial diameter (inner diameter of the stent tube in construction position, ie not expanded) in a range of, for example 10-30mm.

The stent 1 has essentially a wall structure, which is taken over by a standard vascular stent (Coroflex) in outline. That means the stent 1 at least in the area of its widening sections (widening elements) 2 of a number of axially spaced, preferably parallel bands 6 is formed, the schlangen- or accordion-shaped extend in the circumferential direction and thus form in the area of their accordion form flexible expansion reserves in the radial direction.

To increase the stability, the stiffer passage sections (stiffening sections) 4 Seen in the circumferential direction in each case between the two expansion sections 2 (alternately) arranged. The stiffening sections (stiffening elements) 4 are formed by substantially closed, preferably rectangular plate sections, which are seen in their basic shape in the axial direction trough or trough-like arched and are intended to expand not or only slightly radially. The stiffening sections 4 are also used to provide attachment structures for additional separate attachment elements (fluid-tight jacket, tissue protector, bone anchor, lacing device, etc.), as will be described below. The aim here is to place as many functionalities as possible in the geometry of the wall structure.

As further from the 1 and 2a it can be seen, consists of the stent according to the invention 1 from several axially spaced / separate (circular) segments 8th also each consisting of the four peripheral portions as described above, wherein the circular / axial segments 8th through bars 10 (one-piece) are interconnected. This segmental structure has the advantage that with a radial widening of the stent diameter whose axial length remains essentially the same, since only the individual segments 8th be radially expanded. Furthermore, the connecting webs 10 be easily separated with a pair of cutting pliers or scissors or the webs 10 are designed as a predetermined breaking point, so that an intra-operative length adjustment of the stent 1 is possible.

In the area of stiffening sections 4 is the plate-shaped stent wall in segments with U-shaped circumferential passage slots 12 provided, whereby tabs or tongues 16 be formed, which can be bent radially inwardly or outwardly. This results in the axial direction unilaterally open notches / hooks, which serve as mounting elements for separate attachment or additional components.

For example, according to the 2 B . 2c two partially overlapping sealing shells 14 for example, Teflon in the hook 16 mounted, which surround the outer peripheral side of the stent substantially fluid-tight. For this has each (plate-shaped) seal shell 14 a number of recesses 18 into which the hooks 16 intervene and so the sealing shells 14 hold. Because the hooks 16 in areas of the stiffening sections 4 are formed, where the two shells 14 each lie flat against the stent wall, there arise only minor leaks that have no major impact on the fluid retention function and / or the tissue retention function of the shells 14 to have.

As in particular from the 2c it can be seen, have the tabs / tongues / hooks 16 preferably an eyelet function. In other words, the tabs / tongues / hooks 16 not flat but bow-shaped and thus each form a stent wall to the outside or inside bent or umbiegbare eyelet.

In 3 is a first use of this Ösenfunktion shown. In this case, have the expansion sections 2 an inherent elasticity, ie the stent 1 can counter to the spring force of the expansion sections 2 reduced in its active diameter and thus the expansion sections 2 be resiliently biased. Will then the stent 1 released, the widening sections widen 2 back to its original stent diameter (construction position).

As a way, the stent 1 to bias radially in this way is the arrangement of a lacing device 20 about the principle of a corset tie. This is a pull rope or wire of the lacing device 20 through the eyelets 16 threaded, for example, in a cross arrangement. As soon as the two free ends of the pull rope are tightened, the active length of the pull rope shortens between the eyelets 16 causing the stent 1 is contracted radially. When the pull rope is released, the stent expands 1 again spring elastic to its original diameter.

To provide this possibility, the tabs / tongues / eyelets 16 bent radially inward in this case. The inwardly bent tabs / tongues / eyelets 16 then stand for hooking a fluid seal according to the 2a . 2 B no more to disposal. In order to use both add-on parts simultaneously, it is possible to use only a selected number of axially spaced tabs / tongues / eyes 16 bend radially inward and the remaining number radially outward.

According to the 4a are a number of eye-shaped tabs / tongues 16 bent radially outwards, wherein at both stiffening sections 4 outside bone anchor 22 in the form of nails or bolts in the bent tabs / tongues 16 are inserted axially. In contrast, it is also possible, a number of eye-shaped tabs / tongues 16 bend radially inwards and at both stiffening sections 4 inside bone anchor 22 in the form of nails or bolts, as shown in the alternative 4b is shown. In both cases, the bone anchors / screws can 22 be introduced into two spaced-apart bones (eg, example, vertebral body) in a diameter-reduced state of the stent 1 , If this is expanded radially thereto - for example, resiliently by appropriate bias of the expansion sections 2 or by plastic deformation of the expansion sections 2 , the elastic expansion force is transmitted to the two bones and these spaced. The stent 1 is in particular due to the stiffening sections 4 rigid enough to hold the bones and possibly the surrounding tissue at the predetermined distance. That means in this case the stent takes over 1 not only the retraction function according to the above description for the creation of an operation access, in particular for minimally invasive instruments, but at the same time or alternatively the distractor function for the spacing or distance positioning of two (adjacent) bones (vertebral bodies).

It should be noted that the function of the stent 1 also sustained by the shape of the bone anchors 22 depends on or can be supported by them. For example, in the embodiment according to the 4a and 4b used long bolts, which extend over almost the entire stent length laterally on the stent 1 extend. This will cause the stent 1 also supported in terms of its retractor function by the (stabilizing) bone screws over its almost entire axis length, but the diameter of the surgical access now depends on the extent of the distraction.

In contrast, it is in the embodiment according to the 5 provided that a bone screw 22 with screw shank and short screw head (ie without bolt shank) in the end, eye-shaped tabs 16 is used in each case. In this case, the distractor force essentially becomes the axis segment closest to the bones 8th the stent 1 whereas the retractor function of the stent 1 at least partially decoupled by the other segments 8th the stent 1 is provided. In this case, the radial expansion of the bone-nearest segment may occur 8th from the radial expansion of the remaining segments 8th differ (eg be less or greater).

At this point it should be noted that the radial expansion of the stent 1 not necessarily due to the inherent elasticity, especially of the widening sections 2 must be applied. Alternatively, for example, there is the possibility of the expansion sections 2 plastically deform. In this case, the stent 1 After the laser or water cutting, first to the outer diameter of a deflated, from the prior art per se known Dilatationsballons (plastically) are compressed. Preferably, it is manufactured for this purpose in a mean diameter and then radially compressed to the dilatation balloon diameter. This procedure is particularly useful in the retraction function to optimize the ratio of minimum diameter to maximum spread. Ie. when the dilatation balloon is inflated, the stent widens 1 from its compressed position beyond its construction position to its maximum radial spread, without the widening sections 2 to overstretch.

As a material for the stent according to the invention 1 Steel, titanium or plastic can be used, wherein a plastic part is preferably produced by injection molding. Furthermore, the stent 1 be deburred after cutting the wall profiles, for example by electropolishing. Furthermore, in order to improve the photometric reflection properties, for example under microscope applications, the surface of the remaining structures can also be matted or coated.

As indicated above, various instruments and methods may be provided for plastic (non-elastic) retraction. By virtue of the preassembled balloon already mentioned above, the retractor / distractor according to the invention can be used as in a vessel stent 1 be widened hydraulically or pneumatically. As a simple method, a per se known speculum has also been found that can create, for example, an oval opening. Depending on the attachment of the speculum, the stent may 1 can be shaped arbitrarily (plastically). Depending on how the fulcrum of the speculum with respect to the stent 1 is positioned, a funnel-shaped opening, distal or proximal, is possible.

As a further simple (plastic) Spreizmöglichkeit two retractors, eg Langenbeckhaken known design, can be used. If these are supported against each other, there is also a distally funnel-shaped spreading of the stent according to the invention 1 possible. The simplest remedy may be the stent 1 also be spread and shaped with the fingers (plastically).

To remove the stent 1 be destroyed. By simply squeezing it can also be reduced accordingly and then removed. In particular, in the event that a (distal) funnel-shaped structure was created during the expansion process, it is conceivable that, for example, by a compression forceps, which engages in the stent structure, the stent 1 is compressed again. If necessary, the stent structure can also be folded (twisted) by means of rotational moments. Finally, the aforementioned lacing device offers 20 a way to plastically expanded the stent 1 again plastically / elastically compress. So can the pull rope / thread similar to a shoe lace on both stiffening sections 4 in the eyelets formed there 16 is threaded, shortened over its free ends, thereby causing the stent 1 to compress radially.

In particular, for a cervical application, it is advantageous if the distraction function, which otherwise takes place via an additional distrator, into the stent (retractor) 1 is integrated, as already described above. These may include existing Caspar distraction screws as the bone anchors 22 serve. Over the loop-shaped tabs 16 which have been machined into the laser structure and then bent out, become the anchoring points for the screws 22 created. In this procedure, first the screws 22 set and then the stent (retractor) 1 Threaded on the screw shafts or screw heads. In this case, an additional axial securing of the stent according to the invention should still 1 respectively. This can be achieved, for example, via a clamp (not shown) that holds the stent 1 with the screw shaft 22 braced.

For minimally invasive cervical approaches, it has been shown that fixation within the stent (retractor) 1 is more advantageous than on the outside. For this purpose, the stent (retractor) is first 1 set, if necessary spread open until the bone entry points of the fixing screws are in the middle of the cervical vertebrae, then the fixing screws are screwed. This procedure has the advantage that the already screwed screw 22 simultaneously via the screw collar, the axial securing of the stent 1 takes over. It is also conceivable that the screws 22 pre-assembled in the stent (retractor) 1 sit before placing it in the surgical opening.

Will the stent (retractor) 1 after setting with the bone anchors 22 Fixed (distraction screws), so in a more multi-segmental approach, the stent (retractor) 1 be repositioned sequentially by loosening the screws. Similarly, an initial monosegmental approach can be achieved by loosening a screw 22 and then retracting to a multi-segment access.

In a lumbar concept is a fixation of the stent 1 not mandatory. Likewise, an integrated distraction function is more difficult to realize because of the higher forces. A great advantage, however, is when a percutaneous approach with pedicle screws a caudal access is used simultaneously for decompressing and introducing an intervertebral implant.

To align the stent (retractor) 1 in muscle tissue, it may be useful to have an anchoring element 22 is used as a fixing point. This can be eg a pin, a K-wire or the pedicle screw itself. For example, the pedicle screw can be attached caudally to the stent wall. This can be done via an additional component (eg holding cap), which is inserted over the screw head and at the stent (retractor) 1 is fixed.

• – Zwei Schalen, die überlappend montiert sind und sich beim Retrahieren teleskopisch radial auseinanderbewegen (siehe 2b–c). Denkbar sind z.B. Folien aus Teflon.
• – Elastische Folien können aufgewickelt oder als Schlauch über den Stent-(Retraktor) geschoben werden. Ebenso kann der Stent eingegossen werden. Denkbare Materialien sind Elastomere wie PU oder Silikon.
• – Die Eigenschaften von thermoplastischen Elastomeren können genutzt werden, um ein plastisches Fließverhalten beim Retrahieren zu nutzen. Dies hat den Vorteil, dass die Rückstellkräfte im Gegensatz zum rein elastischen Verhalten reduziert werden.
• – Durch einen Sprühprozess kann ähnlich wie bei Gefäßprothesen ein Flies auf dem Stent erzeugt werden.

To protect soft tissue structures, such as vessels, nerves and muscles, it may be necessary for the stent (retractor) 1 with the protective cover 14 is provided. This is especially necessary in the cervical application. Conceivable are films that also on the tabs 16 the laser cutting structure with the stent (retractor) 1 be connected as already above with reference to the 2a -C has been described. However, the following alternative options are generally available, although other variants are conceivable, which are not listed below:

• - Two shells, which are mounted overlapping and telescopically move radially apart during retraction (see 2 B c). For example, films made of Teflon are conceivable.
• - Elastic films can be wound up or pushed as a tube over the stent (retractor). Likewise, the stent can be poured. Conceivable materials are elastomers such as PU or silicone.
• - The properties of thermoplastic elastomers can be used to use a plastic flow behavior during retraction. This has the advantage that the restoring forces in the Contrary to purely elastic behavior can be reduced.
• - By a spray process, similar to vascular prostheses, a fleece can be produced on the stent.

For segmental separation of the stent (retractor) 1 are marks on the jacket / protective cover 14 conceivable, which can be separated with the scalpel. Ideally, they are in the range of metallic segments 8th Perforations on the jacket / protective cover 14 attached, which can be easily separated manually.

• – Single-use Stent-(Retraktor) 1, der beliebig formbar und anpassbar ist
• – Starre Anteile 4 der Stentstruktur werden zur Anbindung an Fixpunkte 16 verwendet.
• – Segmentale Konstruktion ermöglicht individuelles Ablängen des Stent 1.
• – Über die Verbindung zu zwei Distraktionsschrauben 22 kann die Distraktionsfunktion, z.B. bei der cervicalen Anwendung, integriert werden.
• – Eine Ummantelung 14 wird als Gewebeschutz verwendet (starr überlappend oder elastisch bzw. plastisch verformbar). Perforationen an der Ummantelung 14 können zum individuellen Ablängen verwendet werden.
• – Zum Entfernen kann der Stent 1 zerstört werden (Komprimieren, Falten, Aufrollen...).

In summary, according to the invention, a stent (retractor) 1 suggest that has the following properties:

• - single-use stent (retractor) 1 which is arbitrarily malleable and customizable
• - Rigid proportions 4 The stent structure becomes a connection to fixed points 16 used.
• - Segmental construction allows individual cutting of the stent 1 ,
• - About the connection to two distraction screws 22 the distraction function can be integrated, eg in cervical application.
• - A sheath 14 is used as tissue protection (rigidly overlapping or elastic or plastically deformable). Perforations on the casing 14 can be used for individual cutting.
• - To remove the stent 1 be destroyed (compressing, folding, rolling up ...).

• – Der single-use Stent-(Retraktor) 1, ist beliebig (plastisch oder elastisch) formbar und anpassbar und bietet somit Vorteile bei minimal-invasiven Zugängen.
• – Der Stent-(Retraktor) 1 kann für viele Zugänge an der Wirbelsäule (dorsal lumbal, dorsal cervical, ventral cervical) und am Schädel verwendet werden.
• – Starre Anteile 4 der Stentstruktur werden zur Anbindung an Fixpunkte verwendet.
• – Kostengünstige Herstellung der Stentstrukturen durch Laser- oder Wasserschneidverfahren.
• – Übertragung von Erfahrungen aus der Gefäßstentfertigung.
• – Die segmentale Konstruktion ermöglicht individuelles Ablängen.
• – Die Retraktion kann mit einfachen, bereits bekannten Instrumenten, wie z.B. Spekulum oder Langenbeckhaken erfolgen.
• – Über die Verbindung zu zwei Distraktionsschrauben 22 kann die Distraktionsfunktion, z.B. bei der cervicalen Anwendung, integriert werden.
• – Die Schrauben 22 ermöglichen ebenfalls eine axiale Fixierung des Stent-(Retraktors) 1.
• – Eine Ummantelung 14 wird als Gewebeschutz verwendet (starr überlappend oder elastisch bzw. plastisch verformbar). Perforationen an der Ummantelung können zum individuellen Ablängen verwendet werden.
• – Durch die flächige Anlage wird das Zugangstrauma reduziert.
• – Zum Entfernen kann der Stent zerstört werden (Komprimieren, Falten, Aufrollen...).

These properties have the following advantages:

• - The single-use stent (retractor) 1 , is arbitrary (plastic or elastic) malleable and adaptable and thus offers advantages in minimally invasive access.
• - The stent (retractor) 1 Can be used for many accesses to the spine (dorsal lumbar, dorsal cervical, ventral cervical) and skull.
• - Rigid proportions 4 The stent structure is used to connect to fixed points.
• - Cost-effective production of stent structures by laser or water cutting method.
• - Transfer of experience from vascular stent production.
• - The segmental construction allows individual cutting to length.
• - The retraction can be done with simple, already known instruments, such as speculum or Langenbeckhaken.
• - About the connection to two distraction screws 22 the distraction function can be integrated, eg in cervical application.
• - The screws 22 also allow axial fixation of the stent (retractor) 1 ,
• - A sheath 14 is used as tissue protection (rigidly overlapping or elastic or plastically deformable). Perforations on the sheath can be used for individual cutting.
• - Due to the extensive plant access trauma is reduced.
• - To remove the stent can be destroyed (compressing, folding, rolling up ...).

Hereinafter, a second preferred embodiment of the invention with reference to the 1 to 9 in which like reference numerals are used for (construction / function) same elements as in the first example of the invention. Otherwise, only those elements / sections of the stent according to the invention which are different / additionally present in the first example will be described below.

The development of the stent wall according to the 6 shows in this preferred embodiment of the present invention, the two diametrically opposite flared portions / elements 2 as well as in the circumferential direction respectively between them and thus also diametrically opposite stiffening sections 4 , as they are also present in the first embodiment and have already been described above. In contrast to the first embodiment, however, in this case, the stiffening sections 4 from axially spaced segments 8th assembled whose axial length are not the same as in the first preferred embodiment but different from each other.

More concretely, each stiffening section is 2 of a number (plurality) of axially short segments 8a , which in each case via Axialstege (separable / bendable) with each other (fabric) are integrally coupled and at least one other long segment 8b constructed, which also has axial webs same structure / same function with at least one axially last of the short segments 8a is coupled.

As in the first embodiment, close to each short segments (comparable to the segments of the first embodiment) seen in the circumferential direction, an elastically or plastically extensible expansion band 6 on, which connect the diametrically opposite short segments of the same axial plane with each other (fabric integral). The diametrically opposite long segments 8b the same axial plane are over a plurality of axially spaced elastically or plastically stretchable expansion bands 6 preferably of the same construction and the same size as the bands described above 6 coupled together (fabric integral). The axial section along the long segments 8b the stiffening sections forms a widening section for achieving a funnel shape, as described below with reference to FIG 9 and 10 is described.

As further from the 6 and 7 is removable, a number (preferably two) of mounting / mounting tabs are formed at one axial end of the stent. Which preferably take the form of eyelets and are formed in the stent wall, for example by laser cutting. In that regard, the mounting / attachment tabs initially extend flush with the stent wall but may be bent radially inwardly or outwardly of the stent wall converted to a tube / shaft.

In the 6 and 7 are the segments 8a . 8b the stiffening sections 4 represented as closed panels, which over the expansion bands 6 the widening sections 2 are connected together in the circumferential direction to a tube / shaft. Meanwhile, the stiffening portions may be formed with additional functionalities as described in the first embodiment. This is in particular on the 8th directed. Accordingly, the segments 8a and or 8b but preferably the long segments 8b axially end each with radially bendable tabs (according to the first embodiment of the invention) may be formed, which are formed for example by laser cutting of the plate-like segments. Furthermore, the segments 8a and or 8b Through holes / have holes through which wires, cords and / or threads can be pulled. These retractable mounting means may serve to alter the actual diameter of the stent tube or additional elements such as the sealing cups known from the first embodiment 14 to fix (by wiring, jamming or sewing).

• – Lasche(n) zum (klemmenden) Fixieren einer Fluiddichtung/Gewebeschutzes (Überzugs) beispielsweise in Form von Folien, Gefäßprothesen, Schrumpfschläuchen, etc.,
• – Bohrungen zum Vernähen der Fluiddichtung/Gewebeschutzes (Überzugs),
• – Bohrungen zur Drahtaufnahme zum Fixieren der Fluiddichtung/Gewebeschutzes (Überzugs),
• – Bohrungen zur Draht- oder Schnuraufnahme für Kompressionszugmechanismen und/oder
• – Laschen zum Fixieren an Knochenschrauben insbesondere Pedikelschrauben(-systeme) wie z.B. die in 8 dargestellte Laschen für sogenannte „Bodymanipulatoren“.

In particular, on the segments 8a and or 8a the following functionalities can be arranged individually or in a selectable combination:

• - tab (s) for (clamping) fixing a fluid seal / tissue protection (coating), for example in the form of films, vascular prostheses, heat-shrink tubing, etc.,
• - holes for sewing the fluid seal / tissue protection (coating),
• - Holes for wire attachment for fixing the fluid seal / tissue protection (coating),
• - Drill holes for wire or cord holder for Kompressionszugmechanismen and / or
• - Lugs for fixing to bone screws in particular pedicle screws (systems) such as those in 8th shown tabs for so-called "Bodymanipulatoren".

The operation of the stent according to the second preferred embodiment of the present invention substantially corresponds to that of the first embodiment and will be described below with reference to FIGS 9 and 10 explained again.

Like in the 9 can be seen, the stent according to the invention at its widening sections 2 possibly axially differently radially expanded / constricted. In particular, the axial section in the region of the long segments 8b the stiffening sections / elements 4 is particularly suitable for forming a funnel by removing the long segments 8b are bent radially outward at their axial free ends, wherein the long segments 8b with the axially closest short segments 8a connecting webs 10 be bent, causing the stent in the area of short segments 8a substantially retains its radial dimension.

In the 10a and 10b An embodiment of the stent according to the invention according to the first or second embodiment is shown.

As shown in 10a the stent-retractor in combination with, for example, a percutaneous pedicle screw system via a caudal lying insertion sleeve (which is well known in the prior art according to the disclosure of the present applicant itself and therefore need not be described in detail here) threaded / pushed, after removal of the insertion sleeve for the pedicle screw the stent retractor according to the invention is introduced via a dilation system or a guide rod.

Then the stent retractor according to the 10b Distally funnel-shaped radially widened / spread, whereby access is made, for example, to the disc space, for example, to clear the disc and possibly use an intervertebral implant for fusion.

Disclosed is a stent retractor with a radially expandable, tubular shell, which is divided in the circumferential direction in at least two sections, namely a stiffening portion and an expansion portion with mutually different radial flexibility, which are integrally connected to each other. The thus defined stent-retractor is made by a laser or water cutting process preferably from a tube blank.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 6,187,000 B1 [0004]
• US 8372131 B1 [0005]
• WO 2014/022094 A1 [0007]

Claims (11)

A stent retractor with a radially flexible expandable, tubular jacket, characterized in that the jacket in the circumferential direction in at least two sections ( 2 . 4 ) is divided with mutually different radial flexibility, which are integrally connected to each other fabric. Stent-retrakor according to claim 1, characterized in that the jacket in the circumferential direction in four sections ( 2 . 4 ), two of which have substantially the same flexibility as stiffening sections ( 4 ) and the two others are designed with substantially the same flexibility as expansion sections ( 2 ) are designed, for which the two stiffening sections ( 4 ) at least in the circumferential direction and preferably also in the axial direction have a higher rigidity than the two expansion sections ( 2 ). Stent-retrakor according to claim 2, characterized in that the two sections ( 2 ; 4 ) are arranged diametrically opposite each with the same flexibility. Stent-retrakor according to claim 2 or 3, characterized in that the stiffening sections ( 4 ) with receiving and / or fastening structures ( 16 ) are designed or provided for additional components. Stent-retrakor according to claim 5, characterized in that the receiving and / or attachment structures ( 16 ) are formed as preferably bow-shaped or loop-shaped tabs or tongues, which are further preferably in the axial direction of the stent retractor (US Pat. 1 ) and, in cooperation with the stent sheath, each define an undercut open in an axial direction. Stent-Retrakor according to claim 4 or 5, characterized in that as an additional component, a preferably two-part sealing film ( 14 ), which on tabs ( 16 ) as the attachment structures is hung or plugged in and surrounds the stent jacket on the outside under substantially loose plant. Stent-retrakor according to one of claims 4 to 6, characterized in that as an additional component a lacing device ( 20 ) is preferably provided in the form of a pull rope, which in the eye-shaped tabs ( 16 ) is threaded, such that in a lacing preferably while shortening the effective length of the pull rope of the stent retractor ( 1 ) is compressed radially. Stent retrakor according to one of claims 4 to 7, characterized in that as an additional component two bone anchoring elements ( 22 ) are preferably provided in the form of nails or distraction screws, which are diametrically opposed to each other in the eye-shaped tabs ( 16 ) are inserted axially such that they are internally or externally connected to the stent-jacket of the stent retractor (US Pat. 1 ) are in plant. Stent-retrakor according to one of claims 2 to 8, characterized in that the expansion sections ( 2 ) each of a number of axially spaced, preferably elastic expansion elements ( 6 ), which are each preferably formed from a circumferentially extending concertina wire. Stent-retrakor according to one of the preceding claims, characterized in that it can be divided in axial direction into a number of segments ( 8th . 8th ), each with internal stiffening and widening sections ( 2 . 4 ), the segments ( 8th . 8th ) via axial connecting elements 10 ) are coupled to each other preferably with higher stiffness, which further preferably form predetermined breaking points for segment-wise length reduction. Stent-retrakor according to one of the preceding claims, characterized in that the expansion sections ( 2 ) and the stiffening sections ( 4 ) with the structures arranged therein ( 16 ) are produced by laser or water cutting a tube blank.

Images