(19)
(11)EP 2 379 157 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
18.01.2017 Bulletin 2017/03

(21)Application number: 09839022.2

(22)Date of filing:  16.11.2009
(51)International Patent Classification (IPC): 
A61M 25/10(2013.01)
(86)International application number:
PCT/US2009/064636
(87)International publication number:
WO 2010/085292 (29.07.2010 Gazette  2010/30)

(54)

MYOCARDIAL INJECTOR WITH SPRING LOADED PROTECTIVE ARRAY

MYOKARDIALER INJEKTOR MIT FEDERBELASTETER SCHUTZANORDNUNG

INJECTEUR MYOCARDIQUE AVEC RÉSEAU PROTECTEUR SOLLICITÉ PAR RESSORT


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR

(30)Priority: 26.01.2009 US 359812

(43)Date of publication of application:
26.10.2011 Bulletin 2011/43

(73)Proprietor: Schatz, Richard A.
San Diego, CA 92130 (US)

(72)Inventor:
  • Schatz, Richard A.
    San Diego, CA 92130 (US)

(74)Representative: Curley, Donnacha John et al
Hanna Moore + Curley Garryard House
25/26 Earlsfort Terrace Dublin 2, D02 PX51
25/26 Earlsfort Terrace Dublin 2, D02 PX51 (IE)


(56)References cited: : 
US-A- 5 197 971
US-A- 5 882 340
US-A1- 2005 165 355
US-A1- 2007 282 257
US-A- 5 882 340
US-A1- 2002 111 644
US-A1- 2007 282 257
US-B1- 6 461 346
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF THE INVENTION



    [0001] The present invention pertains generally to a system for delivering medicaments to a patient. More specifically, the present invention pertains to a system for performing intra myocardial injections. The present invention is particularly, but not exclusively, useful as a device and system for selectively protecting a needle tip as it is advanced to an intra myocardial injection site.

    BACKGROUND OF THE INVENTION



    [0002] Intravascular catheters are used in a wide variety of medical procedures by inserting the catheter into the vascular system of the patient at an easily accessible location. Thereafter, the tip of the catheter is advanced through the vasculature to a desired target site. In this manner, virtually any target site in the patient's vascular system may be remotely accessed. Of particular interest here are those medical procedure that require the use of injection catheters to inject therapeutic or diagnostic agents into various target tissues within the human body. When so used, an advantage of injection
    catheters is that the target tissue may be accessed by minimally invasive surgical techniques.

    [0003] In many applications the target tissue is within a wall of an organ, such as the heart. For instance, therapeutic or diagnostic agents such as genes, proteins, drugs, plasmids, vectors, stem cells, skeletal myoblasts or any cell therapy may be injected directly into the heart. When the target tissue is within the wall of an organ, however, it is often desirable to inject the therapeutic or diagnostic agent into the tissue proximate the center of the organ wall. In these applications, if the needle of the injection catheter inadvertently passes through the wall, the therapeutic or diagnostic agents that are dispened from the distal end of the needle will not be effectively delivered to the target tissue. Further, because the injection procedure often requires the thrust of a needle in the distal direction, the required motion can cause the catheter itself to contact and perforate or otherwise injure the wall of the organ which can be fatal. Further, it must be ensured that the needle tip does not perforate or damage the aortic and mitral valve apparatus and the chordate tendineae as the injection catheter is advanced to the injection site.

    [0004] US2007/282257 A1 discloses a device for performing intra myocardial injections. The device comprises a needle, a catheter formed with a lumen, and an inflatable abutment member. The abutment member is movable between a first configuration, wherein it is substantially tube-like and is deflated, and a second configuration, wherein it inflates beyond the distal end of the catheter and extends radially. Before the needle is advanced to perform an injection, the abutment member is moved to its second configuration to prevent contact between the catheter and the myocardial tissue during the injection.

    [0005] In light of the above, it is an object of the present invention to provide a system that protects the aortic and mitral valve apparatus and the chordate tendineae from injury and perforation during advancement of an injection catheter to an intra myocardial injection site. Still another object of the invention is to provide a system for performing an intra myocardial injection from a catheter in which a retractable barrier prevents contact between the catheter and the myocardial tissue and allows the physician to advance the needle with confidence and without fear of perforating the myocardial tissue with the catheter. Still another object of the present invention is to provide a system for performing an intra myocardial injection by a single operator that does not require the operator to disengage his hands during the procedure. Yet another object of the present invention is to provide a system for performing intra myocardial injections which is easy to implement, simple to perform, and cost effective.

    SUMMARY OF THE INVENTION



    [0006] In accordance with the present invention as defined in claim 1, an injection system is provided to perform intra myocardial injections, including transvalvular (aortic) or epicardial injections in the left ventricle, or injections in the right ventricle, while preventing unnecessary trauma to ventricle structures or to adjacent myocardial tissue. Structurally, the injection system includes an injection catheter that has a proximal end and distal end and defines a longitudinal axis.

    [0007] Along the axis, the injection catheter is provided with a needle that extends from the distal end of the catheter to a tip. Further, the system provides a flexible array mounted at the distal end of the injection catheter.
    Specifically, the array includes a proximal ring member that is fixedly attached to the distal end of the injection catheter. Also, the array includes a distal non-fixed, sliding ring member which may be moved axially relative to the proximal ring member. Importantly, a plurality of wires interconnects the two ring members.

    [0008] In a protective configuration, the array is substantially cylindrical shaped and is aligned with the axis of the injection catheter. In this configuration, the wires are substantially linear and the distal ring member extends distally beyond or at the needle tip. In a flared configuration, the array is substantially disk-shaped and lies in a plane substantially perpendicular to the axis. Further, each wire is biased to form a loop in the perpendicular plane when the proximal ring member is juxtaposed with the sliding distal ring member to establish the flared configuration.

    [0009] In order to move the array between the protective and flared configurations, the distal ring member is connected to a locking mechanism. Structurally, the locking mechanism includes a contraction spring interconnected between the distal ring member and the proximal end of the injection catheter. Further, a lever is interconnected to the distal end of the spring. In order to control movement of the lever, it is positioned through a guide slot formed in a housing holding the spring. Importantly, the slot forms a notch for holding the lever against the contraction forces of the spring.

    [0010] In order to safely advance the injection catheter to an injection site, the lever is moved axially toward the needle tip to stretch the contraction spring. As a result, the array moves from the flared configuration to the protective configuration. When the array is in the protective configuration, it covers the needle. Further, when the array is in the protective configuration, the lever is received and held in the notch of the slot.

    [0011] After the injection catheter is advanced to the injection site, the lever is released from the notch, and the spring pulls the lever axially away from the needle tip. As a result, the array is pulled back into the flared configuration and the needle tip is exposed. With this arrangement, the needle may be advanced to perform an injection while the flared array abuts and protects the tissue adjacent the injection site.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0012] The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:

    Fig. 1 is a perspective view of an environment wherein an injection system for performing an injection in a patient is being used in accordance with the present invention;

    Fig. 2A is a side view of the injection catheter of Fig. 1, shown with its array in a protected configuration in accordance with the present invention; and

    Fig. 2B is a side view of the injection catheter of Fig. 2A, shown with its array in a flared configuration in accordance with the present invention.


    DESCRIPTION OF THE PREFERRED EMBODIMENTS



    [0013] Referring initially to Fig. 1, an intra myocardial injection system in accordance with the present invention is shown, and is generally designated 10. As shown in Fig. 1, the injection system 10 includes an injection catheter 12 that extends along an axis 14 (shown in Fig. 2A) from a proximal end 16 to a distal end 18. As is shown, the proximal end 16 of the injection catheter 12 is connected to tubing 20. For purposes of the present invention, the tubing 20 is in fluid communication with a vessel 22 for holding medicament 24 or other fluid for medical treatment. Also, a syringe 26 is provided for moving the fluid medicament 24 injection catheter 12 for an injection. As further shown, a guiding catheter 28 forming a lumen 30 is positioned in the vasculature 32 of a patient 34. Specifically, the guiding catheter 28 leads to an injection site 36, retrograde across the aortic valve into the left ventricular chamber, surrounded by adjacent myocardial tissue 38.

    [0014] Referring now to Fig. 2A, the structure of the injection catheter 12 may be understood. As shown, a flexible array 40 is mounted at the distal end 18 of the injection catheter 12. Structurally, the array 40 includes a proximal ring member 42 fixedly attached to the distal end 18 of the injection catheter 12. Further, the array 40 includes a distal ring member 44 that is moveable along the axis 14 relative to the proximal ring member 42. Also, the flexible array 40 includes a plurality of wires 46 that interconnect the ring members 42, 44. As shown, each wire 46 has an end 48 affixed to the proximal ring member 42 and an end 50 affixed to the distal ring member 44. In certain embodiments, the wires 46 may comprise stainless steel, nitinol, cobalt chromium or other desired materials.

    [0015] In Fig. 2A, the flexible array 40 is shown in a protective configuration 40' in which array 40 is substantially cylindrical shaped and is aligned with the axis 14 of the injection catheter 12. However, the array 40 is selectively moveable to a flared configuration 40" shown in Fig. 2B. In the flared configuration 40", the array 40 is substantially disk-shaped and lies in a plane 52 substantially perpendicular to the axis 14. For purposes of the present invention, each wire 46 is biased to form a loop 54 in the perpendicular plane 52 when the proximal ring member 42 is juxtaposed with the distal ring member 44 to establish the flared configuration 40".

    [0016] As shown in Figs. 2A and 2B, the injection system 10 further includes a needle 56 that has a distal tip 58. Importantly, the needle tip 58 is covered by the flexible array 40 when the array 40 is in its protective configuration 40' in Fig.2A. When the flexible array 40 is in its flared configuration 40" in Fig. 2B, the needle tip 58 is exposed to perform an injection.

    [0017] In order to move the array 40 between its configurations 40', 40", the injection system 10 includes a locking mechanism 60. As shown in Figs. 2A and 2B, the locking mechanism 60 is mounted on the proximal end 16 of the injection catheter 12 and engages the flexible array 40 at the distal end 18. Structurally, the locking mechanism 60 includes a contraction spring 62 with an end 64 attached to the proximal end 16 of the injection catheter 12. Further, the spring 62 has an end 66 connected to the distal ring member 44 of the flexible array 40 via a connection arm 68 (shown in phantom).

    [0018] Also, the mechanism 60 provides a push-button lever 70 that is interconnected to the end 66 of the spring 62. As shown, the injection system 10 provides a housing 72 at the proximal end 16 of the catheter 12 for holding the spring 62. Further, the housing 72 forms a slot 74 that limits movement of the lever 70. Importantly, the slot 74 includes a notch 76 that holds the lever 70 against axial movement as described below.

    [0019] For the injection system 10, the spring 62 is biased toward the position shown in Fig. 2B. As a result, the array 40 is biased towards its flared configuration 40". For operation, the lever 70 is moved axially from its position in Fig. 2B to its position shown in Fig. 2A. In Fig. 2A, the lever 70 rests in notch 76 against the contraction force of the spring 62. As can be seen from Figs. 2A and 2B, the array 40 is extending from its flared configuration 40" to its protective configuration 40' when the lever 70 is pushed into the notch 76. When the needle tip 58 is protected, the injection catheter 12 may be advanced through the guiding catheter 28 (shown in Fig. 1) to the injection site 36. After the injection catheter 12 is positioned at the injection site 36, the lever 70 is released from the notch 76 and the spring 62 pulls the distal ring member 44 to position the array 40 in the flared configuration 40". As a result, the array 40 abuts the myocardial wall of the patient 34. Importantly, the array 40 may have a high friction surface for gripping the wall trabeculae. Additionally or alternatively, the array 40 may include tines for gripping the wall trabeculae. After the array 40 grips the myocardial wall, the needle tip 58 may be advanced into the injection site 36 to perform the injection while the array 40 prevents the catheter 12 from perforating or otherwise damaging the adjacent tissue 38. After the injection is performed, the lever 70 is again advanced so that the array 40 is in its protective configuration 40' and the injection catheter 12 is removed from the patient 34, or easily maneuvered for multiple injection sites.

    [0020] In Fig. 2B, the needle 56 has an exposed length from its tip 58 to the distal ring member 44 (as shown in Fig. 2A). In certain embodiments, this length is designed to be less than the thickness of a myocardial wall. As a result, there is no danger of the needle tip 58 passing completely through the myocardial wall. Therefore, a successful myocardial injection is facilitated due to the predetermined exposed length of the needle 56. In certain embodiments, the needle length may be variable using a screw-type mechanism, or a variety of needles having varied fixed lengths (3-6mm) may be provided.


    Claims

    1. A system (10) for performing injections which comprises:

    an injection catheter (12) having a proximal end and a distal end, and defining a longitudinal axis (14);
    a flexible array;
    a needle; characterised in that:

    the flexible array (40) has a distal end and a proximal end, and the array is mounted at the distal end of the injection catheter, with the distal end of the array being retractable in a proximal direction to reconfigure the array from a protective configuration wherein the array is substantially cylindrical shaped and is aligned with the axis of the injection catheter, to a flared configuration wherein the array is substantially disk-shaped and lies in a plane substantially perpendicular to the axis to abut against tissue during an injection; and

    the needle (56) is mounted on the distal end of the injection catheter and covered by the flexible array when the array is in its protective configuration and exposed when the array is in its flared configuration; and

    further comprising a locking mechanism (60) mounted on the proximal end of the injection catheter for engagement with the flexible array at the distal end of the injection catheter, wherein the locking mechanism is selectively manipulable to release the array from its protective configuration to the flared configuration, and to thereafter hold the array in its flared configuration for an injection and to subsequently move the flexible array from its flared configuration to its protective configuration.


     
    2. A system as recited in claim 1 wherein the flexible array comprises:

    a proximal ring member (42) fixedly attached to the distal end of the injection catheter;

    a distal ring member (44) moveable along the axis relative to the proximal ring member; and

    a plurality of wires (46), wherein each wire has a first end affixed to the distal ring member and a second end affixed to the proximal ring member, and wherein each wire is biased to form a loop in the perpendicular plane when the proximal ring member is juxtaposed with the distal ring member to establish the flared configuration for the array.


     
    3. A system as recited in claim 2 wherein the locking mechanism comprises:

    a spring (62) having a first end attached to the injection catheter at the proximal end of the injection catheter and a second end attached to the distal ring member of the flexible array, wherein the spring is relaxed when the array is in its flared configuration; and

    a push-button lever (70) for alternatively advancing the distal ring member to stretch the spring and establish the flexible array in its protective configuration, and for thereafter releasing the distal ring member for a return of the flexible array to its flared configuration under the influence of the spring.


     
    4. A system as recited in claim 3 further comprising a housing (72) for holding the spring, wherein said housing forms a slot (74) that limits axial movement of the lever.
     
    5. A system as recited in claim 4 wherein the slot includes a notch (76) for holding the lever when the flexible array is in its protective configuration.
     
    6. A system as recited in claim 1 further comprising:

    a source of a fluid medicament, wherein the fluid source is connected in fluid communication with the needle; and

    a syringe (26) for moving fluid medicament through the needle for an injection when the flexible array is in its flared configuration.


     
    7. A system as recited in claim 1 further comprising a guiding catheter (28) formed with a lumen 30, wherein the guiding catheter is positioned in the vasculature retrograde across the aortic valve for receiving the injection catheter into the lumen of the guiding catheter.
     


    Ansprüche

    1. System (10) zum Durchführen von Injektionen, das Folgendes aufweist:

    einen Injektionskatheter (12), der ein proximales Ende und ein distales Ende hat und eine Längsachse (14) definiert;

    eine flexible Anordnung;

    eine Nadel; dadurch gekennzeichnet, dass

    die flexible Anordnung (40) ein distales Ende und ein proximales Ende hat und die Anordnung am distalen Ende des Injektionskatheters montiert ist, wobei das distale Ende der Anordnung in einer proximalen Richtung einziehbar ist, um die Anordnung von einer Schutzkonfiguration, in der die Anordnung im Wesentlichen zylindrisch geformt ist und mit der Achse des Injektionskatheters fluchtet, in eine aufgespreizte Konfiguration, in der die Anordnung im Wesentlichen scheibenförmig ist und in einer Ebene liegt, die zu der Achse im Wesentlichen lotrecht ist, um während einer Injektion an Gewebe in Anlage zu sein, umzukonfigurieren; und

    die Nadel (56) am distalen Ende des Injektionskatheters montiert ist und von der flexiblen Anordnung bedeckt wird, wenn die Anordnung in ihrer Schutzkonfiguration ist, und freiliegt, wenn die Anordnung in ihrer aufgespreizten Konfiguration ist; und

    das ferner einen Arretierungsmechanismus (60) aufweist, der für Eingriff mit der flexiblen Anordnung am distalen Ende des Injektionskatheters am proximalen Ende des Injektionskatheters montiert ist, wobei der Arretierungsmechanismus selektiv betätigt werden kann, um die Anordnung aus ihrer Schutzkonfiguration in ihre aufgespreizte Konfiguration auszulösen und um die Anordnung danach für eine Injektion in ihrer aufgespreizten Konfiguration zu halten und die flexible Anordnung anschließend von ihrer aufgespreizten Konfiguration in ihre Schutzkonfiguration zu bewegen.


     
    2. System nach Anspruch 1, wobei die flexible Anordnung Folgendes aufweist:

    ein proximales Ringelement (42), das fest am distalen Ende des Injektionskatheters angebracht ist;

    ein distales Ringelement (44), das relativ zum proximalen Ringelement an der Achse entlang bewegbar ist; und

    mehrere Drähte (46), wobei jeder Draht ein erstes Ende, das an dem distalen Ringelement befestigt ist, und ein zweites Ende, das an dem proximalen Ringelement befestigt ist, hat und wobei jeder Draht vorgespannt ist zum Bilden einer Schleife in der lotrechten Ebene, wenn das proximale Ringelement neben dem distalen Ringelement liegend angeordnet ist, um die aufgespeizte Konfiguration für die Anordnung herzustellen.


     
    3. System nach Anspruch 2, wobei der Arretierungsmechanismus Folgendes aufweist:

    eine Feder (62), die ein erstes Ende, das am proximalen Ende des Injektionskatheters an dem Injektionskatheter angebracht ist, und ein zweites Ende, das am distalen Ringelement der flexiblen Anordnung angebracht ist, hat, wobei die Feder entspannt ist, wenn die Anordnung in ihrer aufgespreizten Konfiguration ist; und

    einen Drucktastenhebel (70) zum abwechselnden Vorbewegen des distalen Ringelements, um die Feder zu spannen und die flexible Anordnung in ihrer Schutzkonfiguration herzustellen, und danach Auslösen des distalen Ringelements für eine Rückkehr der flexiblen Anordnung in ihre aufgespreizte Konfiguration unter dem Einfluss der Feder.


     
    4. System nach Anspruch 3, das ferner ein Gehäuse (72) zur Aufnahme der Feder aufweist, wobei das genannte Gehäuse eine Aussparung (74) bildet, die die axiale Bewegung des Hebels beschränkt.
     
    5. System nach Anspruch 4, wobei die Aussparung eine Kerbe (76) zum Halten des Hebels, wenn die flexible Anordnung in ihrer Schutzkonfiguration ist, aufweist.
     
    6. System nach Anspruch 1, das ferner Folgendes aufweist:

    eine Quelle eines Fluidmedikaments, wobei die Fluidquelle in Fluidverbindung mit der Nadel verbunden ist; und

    eine Spritze (26) zum Bewegen des Fluidmedikaments durch die Nadel für eine Injektion, wenn die flexible Anordnung in ihrer aufgespreizten Konfiguration ist.


     
    7. System nach Anspruch 1, das ferner einen Führungskatheter (28) aufweist, der mit einem Lumen (30) ausgebildet ist, wobei der Führungskatheter zur Aufnahme des Injektionskatheters in das Lumen des Führungskatheters in der Vaskulatur retrograd über die Aortenklappe positioniert ist.
     


    Revendications

    1. Système (10) servant à effectuer des injections qui comporte :

    un cathéter d'injection (12) ayant une extrémité proximale et une extrémité distale, et définissant un axe longitudinal (14) ;

    un réseau souple ;

    une aiguille ; caractérisé en ce que :

    le réseau souple (40) a une extrémité distale et une extrémité proximale, et le réseau est monté au niveau de l'extrémité distale du cathéter d'injection, l'extrémité distale du réseau étant rétractable dans une direction proximale pour reconfigurer le réseau d'une configuration de protection dans laquelle le réseau est d'une forme sensiblement cylindrique et est aligné sur l'axe du cathéter d'injection, à une configuration d'évasement dans laquelle le réseau est d'une forme sensiblement discoïde et repose dans un plan sensiblement perpendiculaire par rapport à l'axe pour venir prendre appui contre le tissu au cours d'une inj ection ; et

    l'aiguille (56) est montée sur l'extrémité distale du cathéter d'injection et recouverte par le réseau souple quand le réseau est dans sa configuration de protection et exposée quand le réseau est dans sa configuration d'évasement ; et

    comportant par ailleurs un mécanisme de verrouillage (60) monté sur l'extrémité proximale du cathéter d'injection à des fins de mise en prise avec le réseau souple au niveau de l'extrémité distale du cathéter d'injection, dans lequel le mécanisme de verrouillage est en mesure d'être manipulé de manière sélective pour libérer le réseau de sa configuration de protection à la configuration d'évasement, et pour par la suite maintenir le réseau dans sa configuration d'évasement pour une injection et pour ultérieurement déplacer le réseau souple de sa configuration d'évasement à sa configuration de protection.


     
    2. Système selon la revendication 1, dans lequel le réseau souple comporte :

    un élément formant anneau proximal (42) attaché de manière fixe sur l'extrémité distale du cathéter d'injection ;

    un élément formant anneau distal (44) mobile le long de l'axe par rapport à l'élément formant anneau proximal ; et

    une pluralité de fils (46), dans lequel chaque fil a une première extrémité fixée sur l'élément formant anneau distal et une deuxième extrémité fixée sur l'élément formant anneau proximal, et dans lequel chaque fil est sollicité pour former une boucle dans le plan perpendiculaire quand l'élément formant anneau proximal est juxtaposé par rapport à l'élément formant anneau distal pour établir la configuration d'évasement pour le réseau.


     
    3. Système selon la revendication 2, dans lequel le mécanisme de verrouillage comporte :

    un ressort (62) ayant une première extrémité attachée au cathéter d'injection au niveau de l'extrémité proximale du cathéter d'injection et une deuxième extrémité attachée à l'élément formant anneau distal du réseau souple, dans lequel le ressort est détendu quand le réseau est dans sa configuration d'évasement ; et

    un levier à bouton-poussoir (70) servant à faire avancer de manière alternée l'élément formant anneau distal pour étirer le ressort et établir le réseau souple dans sa configuration de protection, et pour par la suite libérer l'élément formant anneau distal pour un retour du réseau souple à sa configuration d'évasement sous l'influence du ressort.


     
    4. Système selon la revendication 3, comportant par ailleurs un logement (72) servant à supporter le ressort, dans lequel ledit logement forme une fente (74) qui limite le mouvement axial du levier.
     
    5. Système selon la revendication 4, dans lequel la fente comprend une entaille (76) pour supporter le levier quand le réseau souple est dans sa configuration de protection.
     
    6. Système selon la revendication 1, comportant par ailleurs :

    une source d'un médicament fluide, dans lequel la source de fluide est connectée en communication fluidique avec l'aiguille ; et

    une seringue (26) servant à déplacer le médicament fluide au travers de l'aiguille pour une injection quand le réseau souple est dans sa configuration d'évasement.


     
    7. Système selon la revendication 1, comportant par ailleurs un cathéter de guidage (28) formé avec une lumière 30, dans lequel le cathéter de guidage est positionné dans la vasculature par voie rétrograde en travers de la valvule aortique pour recevoir le cathéter d'injection dans la lumière du cathéter de guidage.
     




    Drawing











    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description