US3416531A - Catheter - Google Patents

Description

Dec. 1 7, 1968 M, EDWARDS 3,416,531

CATHETER Filed Jan. 2, 1964 2 Sheets-Sheet 1M 52 so 52 INVENTOR.

46 MILES LOWELL EDWARDS Attorney Dec. 17, 1968 M. L. EDWARDS 3,416,531

CATHETER Filed Jan. 2. 1964l 2 Sheets-Sheet z lllll Hlll lllll lllll lllll .Hll lllll Hlll Hlll lTHl lIHl IN V EN TOR.

MILES LOWELL EDWARDS United States Patent 3,416,531 CATHETER Miles Lowell Edwards, 13191 Sandhurst Place, Santa Ana, Calif. 92705 Filed Jan. 2, 1964, Ser. No. 335,049 25 Claims. (Cl. 12s-34s ABSTRACT OF THE DISCLOSURE A catheter tube is connected with a manipulative handle. The handle carries a flexible guide tube which is insertable in the catheter tube. A bending element on the distal end of the guide tube is flexed by a pull wire which may be tensioned by a lever on the handle to bend the tip of the catheter tube. Means are provided on the handle for rotating the catheter tube and guide tube and the catheter tube contains torsional reinforcement so that it will rotate uniformly throughout its length.

This invention relates to improvements in a catheter.

It is often necessary to control the direction of a catheter as it is inserted into a tube in the body. For example, it is desirable to use a catheter in diagnosing coronary arteries by visualization with the use of a fluoroscope. A catheter, which is made opaque to X-rays, is inserted in an incision at some convenient point in an artery, for instance in the patients arm, which will lead the catheter to the aorta. Then, as the end of the catheter approaches the coronary arteries which branch from the aorta, the catheter must be guided so that it will change its direction in order to enter the desired coronary artery as its progress is observed in the fluoroscope. For this purpose, means are provided in the present catheter for bending its distal end at an angle to its direction in the aorta.

In addition to merely bending the end of the catheter tube, there exists the problem of orienting the bent end in the desired radial direction. Orienting the distal end of the catheter tube by twisting its proximal end requires a high degree of torsional rigidity in the tube. It cannot be done with facility if the catheter tube has an appreciable degree of torsional flexibility. At the same time, the tube must be quite flexible in bending in order to follow freely a curved path for some distance from the incision and then make a substantially right angle bend into a particular branch artery. A similar problem exists in guiding a catheter into various branch tubes and chambers of the body, other than blood vessels, for various purposes. The conflicting requirements of torsional rigidity and flexibility in bending are not satisfied by conventional catheter tubes where one quality can be attained only at the sacrifice of the other.

The general object of the invention is, therefore, to provide an improved catheter for the purpose described. More specifically, the object is to provide a catheter having a high degree of torsional rigidity without sacrifice of flexibility in bending. Another object is to provide a new and improved means of reinforcement for a catheter tube which has torsional rigidity with flexibility for bending. Another object is to provide an improved device for bending the end of a catheter tube. Still another object is to provide means for measuring blood pressure through a catheter tube and means for injecting and withdrawing fluids through the tube.

The present catheter is made of flexible plastic tubing having incorporated in the wall thereof a novel reinforcement having the described characteristics. The conflicting requirements of torsional rigidity with flexibility in bending are accomplished by a reinforcement of strands arranged in opposite spiral directions. In the present embodiments the reinforcement comprises a tubular braidice ing of monofilament material which is embedded in the wall of the tube but other arrangements of the spiral strands are possible. Such reinforcement causes the distal end of the tube to rotate strictly in conformity to the twisting motion imparted to the proximal end whereby when the distal end is bent it can be guided into a particular branch channel at an angle to the direction of approach. A novel bending device is also provided employing a Bowden wire control manipulable from the proximal end of the catheter tube. In this way, by observing the catheter in a fluoroscope, the distal end may be guided into a branching tube or chamber of the body in any direction around the axis of the approach tube.

The foregoing and other objects and advantages will become apparent and the invention will be better understood from thefollowing detailed description of the preferred embodiment illustrated in the accompanying drawings. Various changes may be made, however, in the details of construction and arrangement of parts and certain features may be used without others. All such modifications within the scope of the appended claims are included in the invention.

In the drawing:

FIGURE 1 is an enlarged side view of a catheter tube containing the improved reinforcement;

FIGURE 2 is a further enlarged fragmentary sectional view taken on theline 22 of FIGURE 1;

FIGURE 3 is a similar view taken on theline 33 of FIGURE 1;

FIGURE 4 is a fragmentary developed view of the reinforcement greatly enlarged;

FIGURE 5 is an enlarged cross sectional view showing the molding operation in the manufacture of the catheter tube;

FIGURE 6 is an enlarged fragmentary side view of a modification with some of the outer plastic material broken away to show the reinforcement;

FIGURE 7 is a vie-w of the bending device showing the parts in bent position in broken lines;

FIGURE 8 is an enlarged longitudinal sectional view of the distal end of the bending device in FIGURE 7;

FIGURE 9 is an enlarged view with parts in section showing the operation of the bending device in a catheter tube;

FIGURE 10 is a view of the proximal end of the bending device with parts in longitudinal section;

FIGURE 11 is a greatly enlarged longitudinal sectional view of the removable catheter bending core in FIGURE 10;

FIGURE 12 is a view taken on the line 1212 of FIGURE 11; and

FIGURE 13 is a view at approximately natural size, showing manipulation of the catheter.

In FIGURE 1 the catheter tube is designated generally by thenumeral 10. On the proximal end of the tube is a conventional metal female connector fitting 11 which, according to standard practice, has a tapered bore for frictional connection with a male fitting on some instrumentality or device which is used with the tube. The distal end portion preferably tapers beginning at apoint 12 to make it more slender and flexible and easier to introduce through restricted passageways and openings. The taper may terminate a short distance from the end. The tube has an end opening 13 and pairs of elongated side openings on opposite sides of the tube at to each other as indicated at 14 and 15. These openings communicate with thelongitudinal passageway 16 which extends throughout the length of the catheter tube. This tapered end portion is designated at 17.

The catheter tube is made of a suitable heat working plastic, such as silicone rubber or polyvinyl chloride, and

incorporated in the wall of the tube is a spirally directed reinforcement to impart torsional rigidity without impairing the flexibility of the tube in bending. This reinforcement preferably comprises strands of a suitable monofilament material such as metal wire, nylon or Teflon. These strands are laid in opposite spiral directions and in the present embodiments are braided together. To avoid possible exposure of cut ends of the strands at the slender distal end of the tube, braiding is started in a first cylindrical layer at the proximal end of the tube and continued to the distal end where it is doubled back upon itself to form a second layer which continues back to the proximal end. This results in a double layer of braiding having anunderlying layer 21 and anoverlying layer 22, as shown in FIGURE 4. In order to distinguish one layer from the other, theunderlying layer 21 has been drawn with heavy lines and theoverlying layer 22 drawn with light lines but it is to be understood that the strands in thetop layer 22 are merely continuations of thestrands 21 of the bottom layer.

In making the tube, a layer of plastic material 24 is applied around a smooth surfaced mandrel orcore rod 25 which has the diameter desired for thepassageway 16. Then a circular braiding machine is employed to braid the strands around the plastic layer and under sufficient strand tension to cause the strands to become embedded in the plastic as the braiding takes place. Outstanding lugs oncore rod 25 form theopenings 14 and 15 at the distal end and, as the layer of braiding reaches these lugs, the braiding is stopped and the strands are crowded together to avoid the lugs, as shown in FIGURE 2, so that the strands will not cross these openings in the finished tube. At the distal end of the tube the braiding operation After completion of the braiding operation, the core member with its layer of plastic and two layers of reinforcement embedded therein is placed in a mold to cure or vulcanize the plastic and form a smooth surface on the exterior of the tube, completely covering the braiding. This step of the process is illustrated in FIGURE 5 where thelower mold member 30 has asemi-cylindrical cavity 31 and theupper mold member 32 has asemicylindrical cavity 33 to receive the plastic coveredcore member 25. The connector fitting 11 is assembled with the core member and plastic cover before the latter are placed in the mold and then when the plastic has been cured, the assembly is removed from the mold and the is reversed to proceed back toward the proximal end with the strands again under suflicient tension to embed them in the plastic layer and crowded around the core lugs which formside openings 14 and 15. In this way there are no out ends of strands at the distal end of the tube. core member withdrawn.

Conventional braiding machines lay pairs of strands spirally over two and under two crossing strands. This is objectionable for the present purpose because the stiffness of the strands causes them to bow outward and inward over and under the crossing strands to a braided thickness considerably in excess of double strand thickness. In order to minimize the wall thickness of the tube for maximum flexibility in bending, the braiding machine is modified to lay single strands over and under single cross-- ing strands. This results in a braided thickness for each layer of braiding exactly equal to twice the strand thickness. Then on the return course of braiding the outer layer strands fall into mesh with the under layer strands so that the two layers of braiding have a combined thickness less than four times the strand thickness.

When monofilarnent strands are used, the strands in one spiral direction are stressed in tension while the strands in the opposite spiral direction are stressed in compression, when the tube is twisted at its proximal end. Monofilament strands of wire, nylon or Teflon have strength in compression as well as tension when confined by being embedded in the wall of the plastic tube. Some advantage over an unreinforced plastic tube is gained by using strands of short fibers spun together as in a textile thread but in such case the strands have no strength in compression and only the tension strands are effective to improve the torsional stiffness. Because of their spiral directions the reinforcing strands, even when metal Wire is used, do not impair the flexibility of the tube in bending. A suitable X-ray opaque material is incorporated in the plastic composition of the tube to provide as much opacity as possible.

FIGURE 6 shows a modification having additional reinforcement up to the point 12a which corresponds to thepoint 12 in FIGURE 1 at the beginning of taper of the distal end. In this case before the two layers of braiding 21 and 22 are applied as above described, a preliminary braiding operation is performed to apply a first layer of braidedstrands 33 from the proximal end out to the point 12a and then reversing back to apply an overlying layer 34 which continues back to the proximal end of the tube. Theextra reinforcement 33, 34 referably underlies thelayers 21, 22 for exterior smoothness, and all four layers are completely embedded in the plastic so that all of the reinforcing strands are covered by the plastic material of the tube. The arrangement in FIGURE 6 provides still greater torsional rigidity throughout the main length of the catheter tube while leaving the tapered distal end portion slender to function as a pilot in guiding the tube through body channels. The four layers of braiding mesh together so that their combined thickness is substantially less than eight times the strand thickness.

When the catheter tube is twisted, the spiral strands in one direction, those under tension, tend to contract inwardly and the spiral strands in the opposite direction, those under compression, tend to expand outwardly. The braiding interlocks the tension and compression strands so that there is no contraction or expansion in the tube. Other strand configurations may be devised to neutralize the contraction and expansion tendencies of the tension and compression strands in order to achieve torsional rigidity. Also, the reinforcing strands may be incorporated in the wall of the plastic tube by other methods of manufacture.

In some cases it may be desired to terminate the strand reinforcement short of the tip in order to provide the greatest possible flexibility in bending at the tip. For this purpose the end portion of the tube may be made of a softer plastic material, the main length of the tube being relatively stiffer for pushing the tube a considerable distance through an artery or vein. The two different plastics may be molded integrally or they may be molded separately and then welded together end to end. The taper need not extend to the tip end. For the present purpose the tip end is made straight for three-fourths of an inch and the tapered portion extends back another threefourths of an inch and the tapered portion extends back another three fourths of an inch. Such details will vary according to the purpose of the catheter and the techniques employed in its use.

An insertable bending device is shown in FIGURES 7 to 13. This device comprises aflexible guide tube 40 for assuming the thrust reaction of a flexibleBowden pull wire 41.Tube 40 is preferably formed by winding a tight coil of spring wire with the adjacent turns in contacting relation so that the tube will not compress longitudinally but is freely flexible in bending. The distal end ofguide tube 40 is seated in abore 42 in ahead block 43 as shown in FIGURE 8. TheBowden wire 41 slides freely throughguide tube 40 and a guide bore 44 in the end of the block. The end ofBowden wire 41 is reversely bent to anchor it in a bore'45 in anend block 46. Surrounding the Bowden wire is acompression spring 47 having its ends abutting the two blocks to urge them away from each other.

Theblocks 43 and 46 are interconnected by aflexible strut 50 at one side of the Bowden wire. This strut comprises a coil of spring wire similar to theguide tube 40.

The coil is incompressible in a longitudinal direction and its ends bear against the confronting faces ofblocks 43 and 46 to maintain a predetermined spacing of the blocks at their under sides as viewed in FIGURE 8. Thecoil 50 is held in this position by a resilientcenter guide wire 51 which passes throughbores 52 in the two blocks and hasopposite end portions 53 bent over the opposite ends of the blocks. Thus, the coil performs the function of a flexible strut While thecenter wire 51 supports the strut in position between the blocks at one side of the Bowden wire. The bendingelement comprising blocks 43 and 46 and associated parts is designated in its entirety bynumeral 55.

TheBowden wire 41 is tensioned by amanual actuating device 60 to bend thestrut 50. One end of tensioningdevice 60 is equipped with a tapered male frictional connector fitting 61 which fits in the bore of female connector fitting 11 on the proximal end of the catheter tube in FIGURE 1. Thus, the bendingelement 55 andflexible guide tube 40 with itsBowden wire 41 may be inserted through thepassageway 16 of the catheter tube until the bendingelement 55 reaches the desired position near the end of the catheter tube, as shown in FIGURE 9. Thehead block 43 andend block 46 are somewhat smaller thanpassageway 16 so that the passageway is not occluded by the bending element.Guide tube 40 is considerably smaller thanpassageway 16. A 90 bend is shown in FIGURE 9. Theelement 55 is capable of producing a 180 bend in the end of the catheter tube. The reinforcingstrands 21, 22 are present in tube in FIG-URE 9 but are not shown. For the present purpose the bendingelement 55 is disposed in the cylindrical portion oftube 10 back of taperedportion 17 but for other purposes the bending element may be located as close to the tip of the tube as desired.

The body of actuatingdevice 60 comprises a fronttubular member 62 and arear tubular member 63. These members contain alongitudinal bore 64 for the Bowdenwire guide tube 40 as shown in FIGURE 10. The rear end ofmember 62 is flanged at 65 for swivel connection to the front end ofmember 63 by means of a threaded union-type coupling 66. An annular recess in the forward end ofmember 63 contains an O-ring seal 67. When coupling 66 is tightened, the swivel joint is locked and made liquid-tight.

The forward end ofmember 62 contains aside branch 68 having apassageway 69 in communication with thepassageway 64. This side branch is equipped with a female connector fitting 11. Mounted on the forward end ofmember 62 is aswivel end member 70 which carries the previously mentionedmale connector fitting 61. This swivel joint is the same as the swivel joint just described betweenmembers 62 and 63 except that in thiscase union coupling 66a may be left sufliciently loose to permit free rotation of the end member by means of itsknurled collar 71. Whenend member 70 is thus rotated, the frictional connection betweenconnector fittings 11 and 61causes catheter tube 10 to rotate and with it theguide tube 40,Bowden wire 41 and bendingelement 55.Guide tube 40 andBowden wire 41 are relativey long and very slender whereby they have negligible torsional stiffness to resist such rotation.End member 70 has alongitudinal passageway 64a communicating withpassageway 64 forguide tube 40. O-ring 67 seals the swivel joint and provides sufficient friction to hold the catheter tube in adjusted rotative position.

The rear end ofbody member 63 contains abore 74 at the end ofpassageway 64 to receive the inner end ofcatheter bending core 75. This core element has a cylindrical metalinner end 76 which fits the bore'74 and is sealed by O-ring 67. Aflange 77 is retained against the end ofmember 63 by means of threaded andflanged union coupling 66b. As shown in'FIGURE 11, thecylindrical portion 76 has abore 78 to receive and seat the proximal end ofguide tube 40 and in continuation of this bore is asmaller bore 79 for theBowden wire 41. Alarger bore 80 contains a pair ofrubber discs 81 which are slightly larger than thebore 80 whereby the discs assume a cupped shape, making a tight seal against the wall of the bore.Bowden wire 41 is pierced through these discs to form a liquid-tight seal between the wire and the discs while at the same time permitting longitudinal movement of the wire. The sealingdiscs 81 are retained by an annularlygrooved metal plug 82 which is secured by a crimped rearwardly extendingcylindrical wall portion 83 integral withcylindrical portion 76 andflange 77. The forward end ofplug 82 and the inner end ofbore 80 are conical to maintain the cupped shape ofdiscs 81 whereby the discs form the equivalent of chevron-type sealing rings.

Ametal bottom 85 has a recessed forward and enclosingplug 82 and anannular rim 86 adapted to seat againstflange 77 Extending through the button is alongitudinal passageway 87 for the Bowden wire and the reduced outer end of the button is provided with adiametral slit 88 which intersects the outer end ofpassageway 87. The button also has anannular groove 89 for actuation by thepalm lever 90 in FIGURE 10. In assembling the bending device, the bendingelement 55 is disposed in straight condition as shown in FIGURE 8 and the proximal end of theBowden wire 41 is bent radially throughslit 88, 360 around the small rear end ofbutton 85 and then again diametrally throughslit 88, and then the walls of the slot are pinched together to clamp and securely anchor the Bowden wire.Guide tube 40 is of a length that will place bendingelement 55 as close to the end of the catheter tube as desired.

Palm lever 90 has a forkedend 91 engagingannular groove 89 to tension the BowdenWire. Palm lever 90 is an L-shaped or bell crank lever which is pivotally mounted at its angle point on apin 92 at the rear end of a supportingarm 93. Aleaf spring 94 in the angle between the two arms urges the palm lever outward to holdbutton 85 normally seated againstflange 77. The forward end ofarm 93 is pivotally mounted at 95 ontubular member 63. This arm is equipped with a coil spring 96 urging the arm toward themember 63 and has afoot 97 to bear againstmember 63. A headedscrew 98 extends through an open ing 99 adjacent the forked end ofpalm level 90 and is threaded throughstop foot 97 to provide an adjustable stop for limiting the squeezing movement ofpalm lever 90 in pulling the Bowden wire rearward.

By lifting supportingarm 93 the forkedend 91 of the palm lever is disengaged frombutton 85 and by unscrewing coupling 6617, thecore element 75,guide tube 40 and bendingelement 55 may be withdrawn from the rear end of the handle body.

From the foregoing description it will be apparent that the manipulation of the catheter banding device involves two different movements which must be coordinated in order to guide the tip of the catheter into a branch artery or other lateral passageway or opening. These two movements comprise the bending action as shown in FIGURE 9 and the rotation of the bent end of the catheter tube to the proper direction. FIGURE 13 illustrates how the bending device provides for coordination of these two movements by a simple manipulation of one hand. Palm or squeezing pressure onlever 90 controls the degree of bending while the thumb and index finger rotatecollar 71 to control the direction of bending.

The frictional engagement of bendingelement 55 with the inside of the catheter tube causes the bending element to rotate with the tube whencollar 71 is rotated. Preferably, the rotative adjustment is performed first while there is but little palm pressure onlever 90. Then, when bendingelement 55 has been oriented in the proper direction to enter the desired ibranch artery, its bending angle may be increased by additional palm pressure onlever 90 as the catheter is pushed forward through the aorta. Also,

small changes in orientation of the bending element may be accomplished during any degree of bending by twisting the wrist to rotate thewhole actuating device 60 as a unit. Stopscrew 93 may be adjusted before insertion of the catheter into the artery, to allow the maximum desired bending angle so that excessive palm pressure during manipulation will not bend the catheter too much.

When the tip of the catheter has been inserted into the desired coronary artery or other branch passage, the entire bending device may be removed, if desired. However, the present bending device is specially constructed so that the usual functions of a catheter tube may be carried out without removing the bending device. This is the purpose ofbranch tube 68.

The exploded portion of FIGURE 13 shows a tree of three-way valves for connection withbranch tube 68. Thesevalves 110, 111 and 112 each have one male connector fitting 61 and two female connector fittings 11 whereby they may be connected together in series to provide branch circuits for various purposes. Each valve has an operatinglever 113 which is rotatable to different positions. It is understood that themale connector 61 ofvalve 110 is inserted in female connector 11 ofbranch tube 68. Thus, the upright connector 11 onvalve 110 may lead to a pressure measuring instrument, the upright connector 11 on valve 111 may lead to an elevated source of glucose solution, the upright connector onvalve 112 may be connected withsyringe 115 and the end connector '71 onvalve 112 may lead to an elevated source of X-ray opaque fluid.

At any time while the catheter is [being used for monitoring pressure readings, the operator can selectively draw either glucose of X-ray opaque material into the syringe. Then by rearranging the valve positions, the material in the syringe may be ejected into the catheter under pressure. Following ejection of material through the catheter, the operator can return to pressure monitoring by re-positioning the first valve. These operations may all be performed while the bendingelement 55 is in the catheter tube or the bending element may be removed, as desired. It is therefore clear that the tube per se may be attached to a variety of instrumentalities.

The swivel joint betweenhandle body members 62 and 63 permits the valve tree to be turned to a convenient position and then the joint may be clamped rigid bycoupling 66.

Although the catheter has been described in connection with coronary artery diagnosis, it is to be understood that no limitation on its use is intended. The principles of the invention are applicable to catheters for all purposes.

As mentioned hereinabove, other strand configurations and other means may be employed to neutralize the contraction and expansion tendencies of the tension and compression strands and the reinforcing strands may be incorporated in the wall of the plastic tube by other methods of manufacture. Polyvinyl chloride, for example, has the advantage of a wide range of degrees of flexibility. It is available in a hard grade which is suitable to act as a binder spiral layers of wire whereby the braiding operation may be eliminated.

In such a process of manufacture, a very thin tube of plastic is first passed over the mandrel. A layer of multiple strands is then wound in one spiral direction and reversed back toward the starting end so as to cross the turns of the under layer of strands. Finally, a heavier tube of plastic is shrunk over the windings to embed the strands and then the assemblage is molded in a die as illustrated and described herein. This leaves all the strand ends at the proximal end of the tube with the turns in one layer being disposed in an opposite spiral direction to the turns of the other layer. The two layers of reinforcing strands are effectively interlocked by the plastic so that the coils of one layer cannot contract or expand relative to the coils of the other layer when the tube is twisted. In this way torsional rigidity is achieved without a braided interlock. It is, of course, understood that the hard plastic employed is not of such hardness as to impair the desired flexibility in bending but merely of sufiicient hardness to provide an effective interlock between the inner and couter courses of the reinforcing strands.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. A manipulative catheter comprising a tube of flexible plastic material having a distal end adapted for insertion into a body passage of a patient and a proximal end adapted to remain outside said body passage, said tube being adapted to be pushed through said body passage, and torsional rigidifying means incorporated in said tube so that said distal end may be rotated to a predetermined orientation in said body passage by twisting said proximal end, said rigidifying means comprising strands of tension material disposed in the wall of said tube in opposite spiral directions so as to impart torsional rigidity without appreciably increasing the resistance of the tube to bending whereby the tube will freely follow curves in said body passage, said strands being disposed in two layers with all the strand ends being at said proximal end of the tube which remains outside the body passage, the underlying layer being doubled back upon itself at the distal end portion of the tube to form an overlying layer continuing from the underlying layer without any strand ends at said distal end of the tube.

2. A catheter as defined in claim 1, said strands in opposite directions being braided together.

3. A catheter as defined inclaim 2, said strands in opposite directions each being braided over one and under one to minimize the thickness of the braided layer.

4. A catheter as defined in claim 1, said strands comprising a monofilament material having strength in compression as well as tension.

5. A catheter as defined in claim 1, including a second double layer of strands extending to a point more remote from said distal end than said first double layer and doubled back so that all its strand ends are at said proximal end of the tube, whereby the distal end portion of the tube is reinforced by a double layer of said strands and the rest of the length of the tube is reinforced by two double layers of said strands, said distal end portion of the tube tapering in thickness.

6. A catheter as defined in claim 1, said two layers of spiral strands comprising a continuous winding extending in a direction away from said proximal end of the tube and then back on itself to said proximal end.

7. In a catheter tube as defined in claim 1, means for bending the distal end of the tube, and means at the proximal end of the tube for actuating said bending means, said bending means being insertable in and removable from said tube.

8. A catheter as defined in claim 1 including a rotatable connection between said body member and said body member connector fitting whereby said catheter tube may be rotated relative to said body member.

9. A device for bending a catheter tube comprising a flexible guide tube having an opening in its distal end portion, a Bowden pull wire slidable in said guide tube, said wire having a distal end portion emergent from said opening in said guide tube, means forming a flexible strut extending beyond said opening and having an outer end connected with the distal extremity of said wire, said strut means having an opposite end adjacent said opening arranged to react against said guide tube when said wire is tensioned causing said strut means to bend, means on the other end of said guide tube for tensioning said wire to bend said strut, and a compression spring coiled around said emergent portion of said wire between said opening and said extremity connection to straighten said strut when said wire is relaxed.

10. A device for bending a catheter tube comprising a flexible guide tube, a head block on one end of said guide tube, a Bowden wire having free sliding movement through said guide tube and head block, an end block connected with one end of said Bowden wire in spaced relation in said head block, a flexible strut extending between said blocks at one side of said Bowden wire for maintaining said spaced relation of said blocks, means on the other end of said guide tube for tensioning said Bowden wire to bend said strut, and a compression spring coiled around said Bowden wire and abutting said blocks at its opposite ends to straighten said street when said Bowden wire is relaxed.

11. A device as defined inclaim 10, said head block having a bore with an end wall to seat said one end of said guide tube, and a bore in said end block arranged to anchor said one end of said Bowden wire.

12. A device as defined inclaim 10, said strut comprising a cylindrical coil of Wire abutting said blocks at its opposite ends, the turns of said wire being in contact with each other so that the coil is longitudinally incompressible, and a guide Wire within said coil anchored at its ends in said blocks.

13. A catheter comprising a molded tube of plastic material, a torsional rigidifying reinforcement molded in the wall of the tube comprising at least one pair of layers of spiral strands of monofilament material, and a device for bending the distal end of the tube comprising a flexible guide tube within said catheter tube, a head block on the distal end of said guide tube, a Bowden wire having free sliding movement through said guide tube and head block, an end block connected with the distal end of said Bowden wire in spaced relation to said head block, a flexible strut extending between said blocks at one side of said Bowden wire for maintaining said space relation of said blocks, means on the proximal end of said guide tube for tensioning said Bowden Wire to bend said strut whereby said catheter tube is bent, and a compression spring coiled around said Bowden wire and abutting said blocks at its opposite ends to straighten said strut when said Bowden wire is relaxed.

14. A catheter comprising a freely flexible and substantially limp tube having a connector fitting on its proximal end, a bending device for said tube comprising a body member having a connector fitting for connection with said tube fitting, a freely flexible and substantially limp guide tube projecting out of said body member fitting removably received in said catheter tube, a bending element on the distal end of said guide tube for bending the distal end of said catheter tube, and means on said body member operable through said guide tube for flexing said bending element.

15. A catheter as defined inclaim 14 including a passageway in said body member containing a proximal end portion of said guide tube and communicating with said first tube, a branch tube connection on said body member communicating with said passageway, and means for closing said passageway on the proximal side of said branch tube connection.

16. A catheter as defined inclaim 14 including means on said body member for rotating one of said tubes relative to said body member.

17. A catheter as defined inclaim 16, said rotatable tube including reinforcement means to impart torsional rigidity to the tube.

18. A catheter handle and bending device comprising an elongated body having a longitudinal passageway therein, a connector fitting for a catheter tube on the distal end of said body in communication with said passageway, a flexible guide tube extending out of said passageway and fitting for insertion in and removal from the catheter tube, a bending element on the distal end of said guide tube for bending the distal end of said catheter tube, a pull wire in said guide tube for flexing said bending element, means in said body for seating the proximal end of said guide tube, an operating lever mounted on said body,

means for detachably connecting said lever with said pull wire, means on said body for rotating one of said tubes relative to said body, a branch tube connection on said body communicating with said passageway, and means on the proximal side of said branch tube connection for closing said passageway.

19. A device as defined in claim 18, said means for detachably connecting said lever with said pull wire comprising a slidable member extending from the proximal end of said body, and means on said member for anchoring the proximal end of said pull Wire, said lever engaging and moving said member to tension said pull wire.

20. A device as defined in claim 18, said elongated body comprising a proximal end member and a distal end member, said operating lever being on said proximal end member and said branch tube being on said distal end member, and means connecting said members together end to end with said operating lever and branch tube turned in different directions about the axis of said longitudinal passageway in adjustable relation.

21. A device for guiding a catheter into a branch tube at an angle from the direction of approach comprising an elongated handle body having a longitudinal passageway therein, a flexible guide tube extending out of said passageway for insertion in and removal from a catheter tube, said guide tube comprising a tight coil of Wire having adjacent turns in contacting relation, a bending element on the distal end of said guide tube, a pull wire slidable in said guide tube for flexing said bending element, means in said body for seating the proximal end of said guide tube, an operating lever mounted on said body for tensioning said pull wire, and means providing detachable connection between said pull wire and operating lever, said guide tube and pull wire being removable from said handle body.

22. A manipulative catheter apparatus comprising a catheter tube having a central passage, said catheter tube having in the walls thereof a plurality of spirally disposed courses of metal wire, said wires terminating at the proximal end thereof, said walls comprising flexible plastic material to prevent fluid passage therethrough, a flexible guide tube held lightly within said passage comprising a tightly wound helical coil of metal wire extending from the proximal end of said passage through a major portion of the length thereof, a cantilever spring attached to the distal end of said guide tube and eccentric thereto, said spring extending loosely through a minor length of said passage, a pull wire within said guide tube attached at its distal end to the distal end of said spring, a lever-equipped handle mechanism rotatably attached to the proximal end of the catheter tube, said guide tube abutting said handle mechanism, said pull wire being attached at its proximal end to the lever of said handle, the combination of which to provide a torsionally stable catheter whereby the bendable distal tip may be manipulated into difficult positions.

23. A manipulative catheter apparatus comprising a catheter tube having a central passage, said catheter tube having in the walls thereof a plurality of spirally disposed courses of metal wire, said wires terminating at the proximal end thereof, said walls comprising flexible plastic material to prevent fluid leakage therethrough, a flexible guide tube held lightly within the passage comprising a tightly wound helical coil of metal wire extending from the proximal end of said passage through a major portion of the length hereof, a helical compression spring of metal wire distal to said guide tube loosely held in said passage abutting and in axial alignment with said guide tube extending through a minor length of said passage, a cantilever spring attached to both ends of said compression spring, a pull wire within said guide tube and compression spring extending the full length of both, the distal end of said pull wire being attached to the distal end of said cantilever spring, a lever-equipped handle mechanism rotatably attached to the proximal end of the catheter tube, said guide tube abutting said handle mechanism, said pull wire being attached at its proximal end to the lever of said handle, the combination of which to provide a torsionally stable catheter whereby the bendable distal tip may be manipulated into difiicult positions.

24. A manipulative catheter for exploring blood vessels comprising: a tube of flexible material having a central passageway and having a distal end for insertion into a tortuous passage in the body of a patient, said distal end having radial openings from said passage through the tube wall and a proximal end adapted to remain outside said passage; means embedded in the wall of said tube resistant to torsional deflection of said tube about its longitudinal medial line; a connector secured to said proximal end and adapted to attach said proximal end to a variety of instrumentalities each adapted to operate through said central passage, said connector, when so attached being freely rotatable relative to said instrumentalities and when thus rotated acting to rotate both ends and all porions of said tube about said medial line, said reinforcing means being so designed that said tube is freely bendable transverse to said medial line.

25. A catheter handle for manipulating a catheter having a bending element in its tip, comprising an elongated body having a longitudinal bore therethrough, a catheter connector fitting swivel mounted on the forward end of said body in communication with said bore for rotating the catheter, an operating lever mounted on said body, a pull wire for flexing said bending element extending through said connector fitting and said bore and connected with said operating lever, a seal for said pull wire in said bore, a branch tube on said body com municating with said bore between said connector fitting and said seal, a thrust tube adapted for insertion in the catheter surrounding said pull wire and arranged to assume the thrust reaction of said pull wire on said bending element, and means in said bore to assume the thrust reaction of said tube.

References Cited UNITED STATES PATENTS 2,688,329 9/1954 Wallace 128-349 3,058,473 10/1962 Whitehead 128349 1,977,209 10/ 1934 Sargent 264103 2,810,424 10/ 1957 Swartswelter 264-103 1,011,090 12/1911 Subers 138130 2,788,804 4/1957 Larkin 138-125 2,961,675 11/1960 Stickney 15-104.38 3,010,357 11/1961 Hirschowitz 1286 X 3,093,160 6/1963 Boggs 138125 2,893,395 7/1959 Buck 128---349 FOREIGN PATENTS 156,901 11/1956 Sweden.

DALTON L. TRULUCK, Primary Examiner.

US. Cl. X.R. 138-123 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,416,531 December 17 1968 Miles Lowell Edwards pears in the above identified It is certified that error ap cted as patent and that said Letters Patent are hereby corre shown below:

line 54, "banding" should reColumn 7 linead bending Column 6, 58 after "binders" insert between Column 8 line 54 the claim reference numeral "1'' should readl4 Column 9,line 10, "street" should read strutline 33, "space should read spaced Signed and sealed this 17th day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, J r.

Commissioner of Patents Attesting Officer

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