CA2184388C - A catheter for injecting fluid or medicine - Google Patents

Abstract

An injection catheter including a catheter stem, a cathetertip, and a bundle of injection needles, wherein either the catheter tip is axially displaceable relative to the catheter shaft or the catheter tip is fixedly connected to the catheter stem and the bundle of injection needles is longitudinally displaceable relative to the catheter tip. The catheter tip may take various forms, as the injection needles within the catheter stem may take various forms and may be guided in various ways. An operating device is provided for effecting relative movements between the injection needles and the catheter tip, which operating device comprises two parts that are controllably displaceable relative to one another, thereby to cause the injection needles to be exposed or retracted. The operating device also includes inlets allowing medication to be applied through the injection needles.

Description

z i s438s A CATHETER FOR INJECThtG A FLUID OR MEDICINE
The invention relates to a catheter for injecting a fluid or medicine into hollow organs and body cavities, particularly into coronary vessels and arteries, comprising: a catheter tip adapted to be inserted into arteries; a catheter stem; a plurality of injection needles arranged in the catheter tip so as to permit relative movement therebetween, said injection needles having their needle points disposed inside the catheter tip in a retracted position and having them protruding from the cathetertip in an exposed position for applying said fluid or medicine; an operating device mounted on the extracorporal end of the catheter for effecting said relative movement; and openings formed in the catheter tip allowing the injection needles to protrude laterally as well as forwardly;
said catheter stem being affixed to one part of the operating device and the injection needles being affixed to the other part thereof such that relative movement of the two parts toward one another will cause the catheter tip and the injection needles to be displaced one relative to the other so as to move the injection needles from said retracted position to said exposed position.
U.S. patent No. 3,598,119 discloses a medical instrument for administering an anaesthetic, wherein an injection needle is guided in an inner coaxial lumen for insertion of the needle under the skin, and a bladder at the distal region can be inflated through an outer coaxial lumen for holding the needle point fixed in position beneath the skin.

?_ 184388 ~Fhe-~ermarr--utiliE~-nl~a-ra-~~-1= '~~s~-an--endoscagi~-i~esEiea da~iE.e-xo~~i~~rr-~~u~t-itza~~I~-~E-R ) .~tiiiaing three coaxial tubes, the outer ane of which ser~~os as a guide for tire two inner tubes employed to imroduce a two-componert ribrin agglutinant which, alter co:nrnin'Tiing at the dis:31 region of the tubes, is applied through an injection needle attached to one of the coaxial tubes.
WO 92 1 O I-~2 discloses a cath..emr inctudil-~g a multi-Iumen catheter stczn in witirh needles are longitudinally movable to extend them thr~ouQh openings in the catheter tip arid thereby insert th~ttt into surrounding tissue for the purpose of introducing therein, through the ~:eeales, fber-optical elements oc therr.tic measuring elements, as the case may ba. ?he hollow needles are suitable for use ut tnsertma flushing and suction appliances.
iJ. S. patent ~to. ~, 5: S,a6I disctoses a catheter for injectir~ a Iicluid into a vein or artery through an c~~ctendible injection ne~te ~.~hich 5 Iongitz:dinaLty mozable in tire front end of the ca*heter and corcrmunicates wish tnz axial Iumen ef the catheter so as, when cxterc~~d, to s~ceive therefrom medicstioa supplied thereto. ?~ two-chamber s~~t~m provided within tile catheter tip , rd includir.r tyro coaxial plungers zvltich are telescopicatfy mo~rable one within the other allows one o~'the plungers to ba employed to ex:end the injection needla, and alloi~,~s the other plunger to be utilized for applying a predetermined dose of medication ihreu~ the injection needle.
~O-A-9~08fi53 discloses a catheter of the kind memion~d herein initially. This catheter utilizes a plurality of injection needles which are longitudinally movable in a .multi-Iumen stem connected to fee catheter tip thrau .~~h a sleeve mounted and cemented thereon.
A corresponding arrangement is di3cIosed in the L'K-A-2269538.
Since a catheter to be used in tr:"atin~ coronary ~~esseIs and arteries n:nst he relati:eiy long and, general3y, may be aw~ut 1.2m tc I.or~z in length there will be a considerable ~:ount of friction generated if a plu;afity of injection neec'Ies within the

-2 -2 i 84388 indi,,zdual lumens of the mufti-lumen stern must be moved over the full length of the catheter. If a mufti-lurncn tube trade of a plastics material is bcina used, such relatively high friction generated over such great lc;~~th can s.so create a problem i:~sofar zs it may result in undesirable Iongitudinat elongation or compression making it di~',cult for the injection nesdles to be precisely positioned within tissue.
It is the principal object of the invention to obviate these drawbacks.
To so~c~e this object, in accordance with the i.-t~s~ention, the injection needles are mounted in the catheter stem and, by sliding the catheter tip relative to the catheter shaft, the catheter needles can either project from the shar2 or assume a retracted position.
This arr~ang~rnent alloa~s surface friction to he greatly reduced to aft extent which depends on the design of the catheter head er the bundle of injection r~eedle~
respectively, thereby enabling a precise positioning of the injection needles within tissr~e_ A very small friction ova the length of thr eathe~c: cazx be aehie4ed with another embodiment of the invention vs~hzerein a mulr~-lumen shaft is utilized in wtzich the injection needles are fixed in the part:cul»r lamina and in whic!t an operaLin~ vn~e extends through s guide lumen within the cathe2e: shaft for retzacting and adv;zncin~ the catheter tip, Ire one pz.rticular embodiment of the inveatioa. injection needles zre combined tp a bundle which is ins~,°aed, behind the distal r~ion of the catheter, irro a flexible tube which has a Large: inside diameter and which recei~~es the injection needles within the catheter stem. This arrangement I-,Ga the acfv~antaue that there are only two tub4lar coaxial lamina which, due to tl:e way in which they are designed and regardless of whether they are made of suitable plastic materials or metals, t~~ill unde.=go no undesirable longitudinal elongation or compression and thus, ~~ill allow the injection needles to Ix properly positi4ned with little effort. Provision is made for the bundle of insertion needles to extend, between the caxheter head and the coaxial latrine, in bundled form o~~er a length asssring, in conjunction ~,~'.th the good flo~-bility of tile bundI~ injection needles, a high degree of flexibility of the distal section of tl:e cathcte~r_

-3 -in order to increase the distal fl~.~-ibitity of the catheter further still, the indivdaal injection needles Frreferably have thinner walls, yet the same diametric flow ~;olumes, in the distal reb on thereof so as to make them thinner and, hence, more tiexible.
The portioay of the injection needles having the thicker walls may either ea~tcrzd throughout their a~hole le.-~~th ihrougll a tubutlr outer stem or may be cemented or soldered in place inside a tubular inner Iumea providzr~ a larger diametric f:ow volume ail the way to the operating device. This will result in considerable over-feed of fluid to the infection needles and, therefore, t~~ih allow the f3uid to be appIietl ev%es~ly_ Tn accordance with a further embodiment of the invention, the catheter stem may have a stainless-steel mesh molded therein, or a stabilizing wire may be incorporated in the catheter stem or the raulti-lumen bundle, respe.."tively, en order to provide improved stability agair_st undesirable longitudinal elongation or compression.
Tn order to facilitate the proper positionir~ or directed guiding of the catheter, there may be provided a guide wire guidzd in a ~~ide lumen enveloped by the bundle of injection needles. 'Flzis guide lume-~ fray also be located eccerr',.rically betw~ee:~ the bundle of needles and the outer stem of the catheter, with thQ ~~ide ~rire exiting e~-tracorporal?y ahead of the operating device. I_f the ~-thezer has no guide lumen, a fide wire may be secured to the distal end of the catheter tip.
L-t order to minimize the friction produced in guiding the inj~tzon needles within the catheter tip, the catheter tip may consist of a bundle of stainless-steel tubes def.-sing lamina through which the injection needles and, if desired, a guide wire extend. This type of ca:heter tip is particularly suitable for usa with pre-bcnr injection nee3les or with needles made of a material urhich is superelast.iv andfor has shape-memory properties. ?.
parti~larty advafztageous manner of ~Tuiding the injection needles within the catheter tip is also ob;a~-~ed by inserting the bundle of i..~jection re~les through a central bore formed in the catheter tip and by having the injection needles laterally issue through guide slots communicating with the central bore.
Obviously, if the catheter tip has therein a plurality of guide Iumina, not all of these need necessarily be occupied by injection needles. Rather, some of them may be available to receive photoconductors for conducting luminous energy through the catheter and to tissue, as needed to activate photo,energizeable substances, if used. Or they may be utilized to insert control and/or measuring systems. In case photoconductors are to be employed, the operating device will have to be suitably modified so as to provide direct access therethrough to the lumina intended to receive the photoconductors.
However, provision also is made for the guide lumina to terminate extracorporally before the operating device so as to enable the photoconductors, or also a guide wire, to be inserted into the catheter.
The operating device for such a catheter includes a thrust plunger for the injection needles or the operating wire, which thrust plunger has a threaded portion thereof threadedly engaged with a knurled nut rotatable to effect axial movement of the plunger, the operating devices also including medication ports communicating with the individual injection needles. It is also possible, however, to control the thrust movements of the thrust plunger pneumatically, hydraulically or electrically by providing the operating device with suitable drive means. Provision may also be made for operating the thrust plunger by foot. Such non-manual kinds of thrust-plunger drives are of particular advantage if the operating device is provided with several medication ports.
Preferably, the operating device is provided with a scale permitting the movements of the thrust plunger to be closely controlled. Stops may be provided for limiting the movement of the thrust plunger.
For special applications, the injection catheter may have attached thereto, distally and/or also proximally with respect to the catheter tip, a balloon for holding the catheter in a fixed position during an injection, and also an angioplastic balloon permitting a dilatation to be performed simultaneously with the injection.
The injection needle lumina may sen%e for inserting control and measuring appliances. Such appliances may include, for example, angioscopes, ultrasonic measuring devices, spectroscopes, devices for measuring activities, concentrations and PH-values, thermometers, and the like Of course, the injection catheter can also be applied through puncture canals for the purpose of treating, for example, tumors, metastases, inflammation sites, convolutions or the Iike~Further advantages and features of the invention will become apparent from the following description of preferred embodiments read in conjunction with the claims and drawings.
Figure 1 shows a catheter tip which is movable in a catheter shaft to effect retraction and extension of injection needles mounted in bundled form within several lumina defined in the catheter stem;
Fig. 2 shows a catheter tip together with retracted injection needles mounted in bundled form within a single-lumen stem;
Fig. 3 shows a catheter tip fixedly connected to a single lumen stem movably supporting therein a flexible tube which has secured thereto a bundle of injection needles movably guided in the catheter tip;
Fig. 4 shows a catheter tip composed of a bundle of tubes and fixedly connected to a single-lumen stem having a bundle of injection needles movably extending there through;
Fig. 5 shows an operating device for displacing a bundle of injection needles within a single-lumen stem;
Fig. 6 is a cross-sectional view, taken along line VI-VI in Fig. 4, of the catheter tip composed of a bundle of tubes;
Fig. 7 shows a further embodiment of a catheter tip; and Fig. 8 is a cross-sectional view of a catheter stem containing needle and guide lumina ?_ 184388 Figure I illustrates the distal end structure 10 of a catheter including a catheter tip I 1 which is axially movable in a supporting sleeve 12 which is connected to a mufti-lumen stem 14 having injection needles 15 secured thereto within the various lumina.
Guided within a central guide lumen 16 is an operating wire 17 which is anchored to the catheter tip 11 and by means of which the latter can be axially displaced. In Fig. l, the catheter tip is shown in a retracted position in which the injection needles 15 extending through longitudinal guide grooves 18 of the catheter tip are deflected outwardly to exposed positions thereof in which they can puncture tissue surrounding the catheter.
Preferably, the injection needles are pre-bent at their distal ends so as to facilitate their being deflected outwardly by cam surfaces formed in the various guide grooves. The needles are preferably made of stainless steels or special alloys lending them enough flexibility to be deflectable outwardly through the action of the catheter tip, yet making them also stiff enough to penetrate tissue. Tissue penetration can be optimized through use of suitably ground needles.
In Fig. 2 illustrating a modification of the distal end structure 20 of the catheter, the catheter tip 11 is shown displaced forwardly to an extended position in which the injection needles 15 are disposed completely inside the guide grooves 18. This is the position for inserting the catheter into an artery or vein, such insertion being facilitated by a guide or so-called fixed wire 19 attached to the front or leading end of the catheter. In the catheter shown in Fig. 2, the injection needles 15 are likewise combined in a bundle and, as such, are secured to a single-lumen stem 22 interiorly thereof. The operating wire 17 extends movably through the inner space defined by the bundle of injection needles, and is guided by the needles. It is anchored to the catheter tip 11 and is axially movable to extend the catheter tip from or to retract it into the distal end portion of the catheter.
Fig. 3 illustrates still a further embodiment of the invention wherein the bundle of injection needles 15 is axially movable inside the single-lumen stem 14, and the catheter tip 11 is fixedly connected to the single-lumen stem 14 through the retainer sleeve 12.
Disposed within the single-lumen stem 14 is a flexible tube 24 which has rear portions of the injection needles 1~ inserted into and secured, i.e. cemented or soldered, to a front portion of the tube so that axial movement of the flexible tube 24 within the single-lumen ?_ 184388 stem 14 in opposite directions will cause the injection needles to be retracted into or extended from, respectively, the catheter tip 11. In order to dive the distal end structure a high degree of flexibility, the distance between the catheter tip 11 and the flexible tube 24 can be substantially greater than depicted in Fig. 3; which means that, in deviation from what is shown, the retainer sleeve 12 does not extend to the region in which the flexible tube 24 is movable. In order to improve sliding ability, the flexible tube 24 preferably is coated with an antifriction material, such as PTFE, for example. The same applies with respect to the injection needles movable in the multi-lumen stem shown in Fig.
1 and in the single-lumen stem shown in Fig. 2.
Fig. 4 shows still another embodiment of the invention wherein the distal end structure 40 of the catheter includes a catheter tip consisting of a bundle of tubes 41 (see also Fig. 6) which extend to a single-lumen tube 22 fixedly connected to the catheter tip through the retainer sleeve 12. The pre-bent injection needles 45 extend through, and are axially movably in the single-lumen tube 22 and the individual tubes 41. The injection needles have a smaller diameter in the regions of the catheter tip and single-lumen stem 22 than throughout the remaining part of the catheter, which makes the front ends of the injection needles highly flexible whilst at the same time assuring optimal stiffness and flexibility in the region of the catheter stem. The injection needles which are slidably supported in the single-lumen stem 22 preferably are coated with a suitable antifriction material. A center lumen within the bundle of injection needles 45 is preferably left free to accommodate a guide wire 43 which extends further into a corresponding tube within the tube bundle 41 and can protrude therefrom at the front end of the catheter. In order to reduce internal friction and to allow medication to be injected at a lower pressure, the portions of the injection needles 45 having the larger outer diameter may also have an inside diameter which is larger than that of the needle points. Althoujh Fig.

4 depicts the lamer-diameter sections of the injection needles likewise as spaced from the catheter tip a relatively short distance, it will be understood that these thicker sections of the needles should preferably be spaced from the support sleeve 12 a greater distance in the interest of increased flexibility at the catheter tip.

Referring, now to Fig. 5 of the drawings, there is shown therein an operating device for effecting extension of the injection needles. This operatin~, device, generally designated with numeral 50, comprises essentially two parts 54 and 55 referred to herein as the stationary part 54 and as the movable part 55, respectively. The movable part 55 includes a thrust plunger 56 which is slidable in a cylinder 57 of the stationary part 54 and has connected thereto the extracorporal ends of the injection needles, the movable part 55 includes medication inlets 59 and bores 58 providing fluid flow communication between the medication inlets 59 and the corresponding injection needles. The movable part 55 further includes a bore 60 which extends into the wide volume within the catheter stem.
The thrust plunger 56 has a thread threadedly engaged with a knurled nut 62 which is captively supported on the stationary part 54 and rotatable to displace the thrust plunger 56 inwardly of the cylinder 57 and thereby effect a corresponding movement of the injection needles connected thereto. The cylinder 57 may be provided with a scale 65 and the thrust plunder 56 with an indicating line 66 for indicating the extent of plunger displacement and thereby allowing it to be accurately controlled. The cylinder 57 has connected thereto the catheter stem 22 which may have a stainless-steel wire mesh 52 incorporated therein in order to stabilize it ajainst undesirable longitudinal elongation and compression while the injection needles are being displaced. It should be noted that the operating device as illustrated in the drawing is specially adapted for use with a catheter employing a distal end structure such as hereinbefore described with reference to Fig. 4.
If to be used together with a catheter employing a distal end structure such as shown in Fig. 3, the operating device 50 will have the flexible tube 24 instead of the bundle of injection needles connected to its thrust plunger 56, and there will be provided only one medication inlet 59 which will be in fluid flow communication with the space within the flexible tube 24.
A catheter utilizing a distal end structure such as shown in Fig. 1 or 2 will have the extracorporal ends of the injection needles connected to the stationary part 54 of the operating device 50 which, for this purpose, will have corresponding medication inlets formed therein. The movable part 55 of the operating device will, in this case, act upon the operating wire 17 to effect longitudinal movement of the catheter tip 11 of the distal end structure.
:although not shown in the drawings, the guide lumen for the guide wire may have its outlet located, not at the operating device, but ahead of it in the extracorporal region of the catheter stem, for which purpose the guide lumen is arranged eccentrically between the bundle of injection needles and the outer stem.
Furthermore, the stem of the catheter may have connected thereto a stabilizing wire which may be either molded into the outer jacket of the stem or, if the stem is a mufti-lumen stem, may be mounted, preferably glued, in place within a lumen.
In Fig. 8 which is a cross-sectional view of a catheter having a single-lumen stem, the two lumina for the guide wire and the stabilizing wire are shown, by way of example, as molded into peripheral wall portions of the stem, whereas the bundle of injection needles is arranged to be freely movable within the stem.
The catheter tip can be made from various materials, plastics as well as metal, ceramics or glass, and desirable maybe of a radio-opaque design.
Furthermore, the lumina which are movable within the catheter preferably are sealed within the catheter against liquid reverse flow, for example by means of suitable lubricants.
In order to stabilize the catheter stem, the latter may be torsioned; and in order to ensure that the injection needles will emerge from the catheter tip smoothly, the bundle of injection needles may be arranged within the catheter stem along an elongated helix. This will result in improved movability, especially if employed in combination with friction-reducing lubricants.
The functional operation of the injection catheter can be optimized by attaching to the catheter, in a previously proposed manner, balloons adapted to fix the catheter in position during an injection. Angioplastic balloons arranged distally as well as proximally with respect to the catheter tip will also improve the applicability of the catheter and, in particular, may help to enable a balloon dilatation to be performed simultaneously with an injection of medication into the affected tissue.

Claims (13)

We claim:

1. A catheter for injecting a fluid or medication into hollow organs and body cavities, particularly into coronary vessels and arteries, comprising: a catheter tip (11) adapted to be inserted into arteries; a catheter stem (12,14;12,22); a plurality of injection needles (15) arranged in the catheter tip for movement therein, said injection needles having needle points which, in a retracted position, lie inside the catheter tip and, in an extended position, lie exposed in readiness for applying said fluid or medicine; an operating device (50) connected to the extracorporal end of the catheter;
openings (18) formed in the catheter tip and allowing the needles points to protrude therefrom laterally as well as forwardly; said catheter stem (12,14;12,22) being connected to one part (57) of the operating device and the injection needles (11) being connected to the other part (56) thereof; the arrangement being such that movement of one of said two parts in a predetermined direction relative to the other effects a corresponding relative movement between the catheter tip and the plurality of injection needles (15), thereby causing the needle points to be moved from the retracted position to the extended position thereof, said injection needles being joined together as a bundle displaceable relative to the catheter tip characterized in that the injection needles joined together as a bundle are connected to the catheter stem (12,14;12,22) and that the injection needles by movement of the catheter tip (11) relative to the catheter stem are positioned in said extended position or said retracted position.

2. A catheter according to claim 1, wherein the catheter stem (14) is a multi-lumen stem having injection needles (15) secured within the various lumina, and wherein an operating wire (17) is guided within a guide lumen (16) of said catheter stem for retracting and extending of the catheter tip (11).

3. A catheter according to claim 1, wherein the catheter stem (14) is a single-lumen stem (22) within which the bundle of injection needles (15) guides, in its inside, the guide wire (17) connected to the catheter tip (11).

4. A catheter for injecting a fluid or medication into hollow organs and body cavities, particularly into coronary vessels and arteries, comprising: a catheter tip (11) adapted to be inserted into arteries; a catheter stem (12,14); a plurality of injection needles (15) arranged in the catheter tip for movement therein, said injection needles having needle points which, in a retracted position, lie inside the catheter tip and, in an extended position, lie exposed in readiness for applying said fluid or medicine; an operating device (50) connected to the extracorporal end of the catheter; openings (18) formed in the catheter tip and allowing the needles points to protrude therefrom laterally as well as forwardly; said catheter stem (12,14) being connected to one part (57) of the operating device and the injection needles (11) being connected to the other part (56) thereof; the arrangement being such that movement of one of said two parts in a predetermined direction relative to the other effects a corresponding relative movement between the catheter tip and the plurality of injection needles (15), thereby causing the needle points to be moved from the retracted position to the extended position thereof;
said injection needles being jointed together as a bundle displaceable relative to the catheter tip, characterized in that the injection needles (15) joined together as a bundle are inserted, behind the distal region of the catheter, into a flexible tube (24) receiving the injection needles (15) within the inside diameter of the catheter stem (14).

5. A catheter for injecting a fluid or medication into hollow organs and body cavities, particularly into coronary vessels and arteries, comprising: a catheter tip (11) adapted to be inserted into arteries; a catheter stem (12,14); a plurality of injection needles (15) arranged in the catheter tip for movement therein, said injection needles having needle points which, in a retracted position, lie inside the catheter tip and, in an extended position, lie exposed in readiness for applying said fluid or medicine; an operating device (50) connected to the extracorporal end of the catheter; openings (18) formed in the catheter tip and allowing the needles points to protrude therefrom laterally as well as forwardly; said catheter stem (12,14) being connected to one part (57) of the operating device and the injection needles (11) being connected to the other part (56) thereof; the arrangement being such that movement of one of said two parts in a predetermined direction relative to the other effects a corresponding relative movement between the catheter tip and the plurality of injection needles (15), thereby causing the needle points to be moved from the retracted position to the extended position thereof, said injection needles being joined together as a bundle displaceable relative to the catheter tip, characterized in that the catheter stem is a single-lumen stem (22) within which the injection needles (45), joined together as a bundle, are movable relative to the catheter stem in such a way that the injection needles (45) are positioned either in the extended or retracted position.

6. A catheter according to claims 1, 2 or 5, wherein the injection needles (15;45) have a reduced wall thickness, but the same flow cross-section, in the distal region thereof.

7. A catheter according to claim 5, wherein a guide wire (43) is guided eccentrically between said bundle of injection needles (45) and the catheter stem and protrudes outwardly at an extracorporal location before the operating device (50).

8. A catheter according to claim 2, characterized in that the operating wire (17) extends through a guide lumen (60) within the catheter stem for retracting the catheter tip (11) respectively into and from the catheter stem.

9. A catheter according to claims 1, 4 ar 5 characterized in that the catheter tip (41) consists of a bundle of stainless-steel tubes defining lumina which having the injection needles (45) and a guide wire (43) extending therethrough.

10. A catheter according to claims 1, 4 or 5 characterized in that the bundle of injection needles (15) extends through a central bore (32) of the catheter tip and being laterally extendible through guide grooves (18).

11. A catheter according to claims 1, 4 or 5, characterized in that the catheter stem has a stainless-steel wire mesh (52) molded therein.

12. A catheter according to claims 1, 4 or 5, characterized in that said catheter stem has a stabilizing wire (67) incorporated therein.

13. A catheter according to claims 1, 4 or 5, characterized in that said operating device (50) includes a thrust plunger (56) for effecting displacement of said operating wire (17), said thrust plunger (56) having a threaded portion (61) which is threadedly engaged with a knurled nut (62) operable to effect axial displacement of the thrust plunger, and said operating device including medication inlets (56) which communicate with the individual injection needles (15).