Device for manipulating a guide wire unit

Abstract: The invention relates to a device (10) for manipulating a stylet unit (12) for positioning an electrode cable in a body cavity. The device (10) comprises an elongate housing (18), an elongate, axial cavity (24) in the housing (18) and an operating slide (32), axially moveable in relation to the housing (18), for attachment to a proximal end section (40) of a tubular stylet sleeve of the stylet unit. An elongate coil spring means (26) is located in the cavity (24) on the proximal side of the operating slide (32). The coil spring means (26) forms an inner guide channel to prevent buckling of the free, proximal end section (14a) of the stylet unit's stylet in the cavity (24).

Description: Field of the invention The present invention relates to a device for manipulating a stylet unit for positioning an electrode cable in a body cavity, said device containing an elongate housing with a proximal and a distal end section, an elongate axial cavity in the housing and an operating slide, axially movable in relation to the housing, for connection to a proximal end section of a tubular stylet sleeve of the stylet unit. The prior art US-A-5 170 787 describes a previously known device for manipulating a stylet unit in order to achieve a desired stiffening of an electrode cable during its advancement into a body cavity, e.g. through a vein in an atrium of the heart, and to achieve a desired final positioning of the distal end of the electrode cable by giving it an L or J shape. The stylet unit used for this purpose consists of an inner stylet enclosed in a tubular stylet sleeve. The distal end of the stylet is pre-curved. It is kept retracted inside the stylet sleeve during the electrode cable's introduction into the body cavity in order to keep the distal end of the electrode largely straight The stylet is deployed out of its tubular sleeve, when the distal end of the electrode cable is to be placed in its final position, to bend the distal end of the electrode cable into the desired curved shape. In order to achieve deployment of the pre-curved distal end of the stylet out of the tubular sleeve, US-A-5 170 787 proposes a device which either pushes the stylet out in a distal direction in relation to the stationary tubular sleeve or slides the tubular sleeve in a proximal direction in relation to the stationary stylet. However, the latter version is preferable, since there is then no displacement of the electrode cable in relation to the stylet's manipulation device. The known manipulation device contains two stiff, telescoping tubes to provide non-buckling stiffening of the stylet when its proximal end of the manipulation device is slid distally into the tubular sleeve or when the tubular sleeve is slid proximally over the free proximal end of the stylet in the manipulation device. This means that the manipulation device is relatively long, since the total length of telescoping tubes must be twice the length of the stylet's stroke movement in relation to its tubular sleeve. Summary of the invention The object of the present invention is to achieve a manipulation device, of the kind cited above, with a much shorter length and fewer components than the aforementioned prior art manipulation device. For this purpose the manipulation device according to the invention has an elongate cavity devised to enclose, with a tight fit, an elongate coil spring means on the proximal side of the operating slide, said spring means forming an inner, axial guide channel to prevent a free, proximal end section of a stylet of the stylet unit in the cavity from buckling when the proximal end section of the stylet sleeve is slid over the free proximal end section of the stylet with the aid of the operating slide, while shortening the length of the spring means. Since the stiff, telescoping tubes in the known design have been replaced by stylet-supporting, compressible coil spring, the total length of the manipulation device can be greatly shortened, and the number of parts in the manipulation device can be reduced, thereby making it cheaper to manufacture. Additional distinguishing feature of the invention are defined in dependent patent claims 2-12. The invention will now be described below in greater detail, referring to the attached drawing. Description of drawings FIG. 1 is a lateral view of a stylet manipulation device according to the present invention; FIG. 2 is a sectional view of the manipulation device along the line II-II in FIG. 1; FIG. 3 is an enlarged sectional view of the circular area III in FIG. 2; and FIG. 4 is a sectional view along the line IV-IV in FIG. 2. The preferred embodiment FIGS. 1 and 2 show a manipulation device, generally designated 10, for a stylet unit, for achieving a desired stiffening of an electrode cable (not shown) during its introduction into a body cavity, e.g. through a vein in the right atrium of the heart, and a desired positioning of the distal end of the electrode cable against the heart wall for fixation of the end there. The manipulation device 10 is intended for manipulating a stylet unit 12 of the kind containing an internal stylet 14 (shown most clearly in FIG. 3) and a tubular sleeve 16 enclosing same, both the sleeve 16 and the stylet 14 intended for introduction inside the central channel of an electrode cable to stiffen the cable during its introduction. This stylet unit 12 is designed to bend the distal end of the electrode cable into e.g. a J shape when the cable reaches its final position. For this purpose, the internal stylet's 12 distal end is pre-curved in a known manner, but it is kept enclosed inside the tubular sleeve 16 during the electrode cable's introduction, thereby keeping the distal end section of the stylet unit 12 and, accordingly, the electrode cable essentially straight When the distal end of the electrode cable has been advanced e.g. into the right atrium of the heart, the tubular stylet sleeve 16 can be retracted, whereupon the pre-tensioning of the curved, exposed distal end section of the stylet 14 bends the flexible, distal end section of the electrode cable into the desired L or J shape. The manipulation device 10 according to the invention is therefore designed to control the movement of the tubular sleeve 16 in relation to the stylet 14. The device 10 comprises an elongate cylindrical housing 18 with a proximal end section 20 and a distal end section 22. A cavity in the form of a channel or hole 24, devised to admit the stylet sleeve 16, containing the stylet 14, with a tight fit, passes through the center of the housing 18, as well as through a coil spring means 26, a free, proximal end section 14a of the stylet passing through a guide channel 27 in the spring means 26 (FIG. 4) to an attachment point F (FIG. 2) on the proximal end section 20 of the housing 18. The housing 18 has an elongate, axial slot 28 which passes diametrically through the hole 24 (FIG. 4), the hole 24 in this slotted section of the housing 18 then being limited by two opposing, semicylindrical walls 30a, 30b. As shown in greater detail in FIG. 3, an operating slide 32 is arranged to move axially along the housing 18 and has a ring collar 34 which is connected to a hub section with two diametrically opposed radial pins 36 which pass through the slot 28, the proximal end 40 of the tubular sleeve 16 being affixed to said hub section. In one appropriate embodiment, the coil spring means 26 is a pressure spring whose proximal end rests against or is mounted on a proximal end section 42 affixed to the proximal end 20 of the housing 18, whereas the distal end of the coil spring means presses against the proximal end section 40 of the tubular sleeve 16 and/or against the operating slide's 32 hub section 26 which affixes this end section. Or the spring means 26 can consist of a draw spring whose ends are mounted on the end section 42 and tubular sleeve 16 or hub section 38. An end section 44, with an axial, distally projecting shaft journal 46 on which a known sleeve (not shown) can be mounted and which can be connected to a contact pin on the proximal end of the electrode cable to permit rotation of the cable during active fixation of the cable's distal end, is mounted on the distal end 22 of the housing 18. The manipulation device 10 according to the invention works in the following manner. Before the electrode cable is introduced into the body cavity, the stylet unit 12 is fully inserted into the electrode cable with the stylet 14 enclosed by the tubular sleeve 16, i.e. the operating slide 32 is kept in a forward, distal end position in the housing 18. When the distal end of the tubular sleeve 16 reaches the distal end of the electrode cable, the latter can be advanced into the body cavity, e.g. the right atrium of the heart. After it reaches the atrium, the distal end section of the electrode cable is bent into the desired L or J shape when the physician manually retracts the operating slide 32 with his fingers, i.e. in the proximal direction, such that the slide 32 moves the tubular sleeve 16 and exposes the pre-curved distal end of the stylet 14 which accordingly bends the end of the electrode cable into the desired shape, depending on how much of the curved distal end of the stylet is exposed. When the spring means 26 consists of a draw spring, the spring means 26 tends to contract, thereby facilitating the operating slide's 32 movement in the proximal direction. When the spring means 26 is a pressure spring, this spring is compressed by the operating slide. In both instances, the primary task of the spring means 26 is to enclose, with a tight fit, or "brace" the proximal end section 14a of the stylet 14, thereby keeping this free end section 14a from being buckled by the stylet 14 because of friction between the stylet 14 and the sleeve 16. As a result of the shortening of the length of the spring means 26, the total length of the manipulating device 10 can be kept relatively short. When the distal end of the electrode cable reaches its final position, it can be actively affixed to the heart wall by manual rotation of a rotation sleeve (not shown) mounted on the shaft journal to which the electrode cable's proximal contact pin is affixed.

Claims: A device for manipulating a stylet unit (12) for positioning an electrode cable in a body cavity, said device (10) containing an elongate housing (18) with a proximal (20) and a distal (22) end section, an elongate axial cavity (24) in the housing (18) and an operating slide (32), axially moveable in relation to the housing, for connection to a proximal end section (40) of a tubular stylet sleeve (16) of the stylet unit (12), characterized in that the elongate cavity (24) is designed to enclose, with a tight fit, an elongate coil spring means (26) on the proximal side of the operating slide (32), said spring means (26) forming an inner, axial guide channel (27) to prevent a free, proximal end section (14a) of a stylet (14) of the stylet unit (12) from buckling when the operating slide (32) is retracting the proximal end section (40) of the stylet sleeve (16) over the free proximal end section (14a) of the stylet, while shortening the length of the spring means (26). A device according to claim 1, characterized in that the spring means (26) consists of a pressure spring with a proximal end and a distal end. A device according to claim 2, characterized in that the proximal end of the spring means (26) is affixed to the proximal end section (20) of the housing (18). A device according to claim 3, characterized in that the distal end of the spring means (26) is arranged to press against the proximal end section (40) of the stylet sleeve (16). A device according to claim 3, characterized in that the distal end of the spring means (26) is arranged to press against a hub section (38) of the operating slide (32). A device according to claim 2, characterized in that the spring means (26) consists of a draw spring with a proximal end attached to the proximal end section (20) of the housing (18) and with a distal end attached to the proximal end section (40) of the stylet sleeve (16) or the hub section (38) of the operating slide (32). A device according to any of claims 1-6, characterized in that the housing (18) has an axial, elongate slot (28) connecting the cavity (24) in the housing to the exterior of same. A device according to claim 7, characterized in that the cavity (24) is formed by a cylindrical hole in the proximal end section (20) of the housing (18) and by two opposed semicylindrical surfaces (30a, 30b) in the slot section of the housing (18). A device according to claim 7 or 8, characterized in that the operating slide (32) contains at least one trunnion (36), radially projecting from the proximal end section (40) of the stylet sleeve (16) which can move in the slot (28). A device according to claim 9, characterized in that the operating slide (32) comprises manipulation means (34), connected to the trunnion (36) which is movably journalled on the exterior of the housing (18). A device according to claim 10, characterized in that the manipulation means (34) is ring-shaped. A device of any of claims 1-11, characterized in that the distal end section (22) of the housing (18) has an axially projecting shaft journal (46) for a means for rotating the electrode cable. A device according to any of claims 1-12, characterized in that the proximal ends of the coil spring means (26) and stylet (14) are attached to fixed end section (42) on the proximal end section (20) of the housing (18).

Inventors: BOSTROEM MATS, NEUBAUER HEINZ, BOSTROEM, MATS, NEUBAUER, HEINZ, Boström, Mats
Applicants: ST JUDE MEDICAL, ST. JUDE MEDICAL AB
Application year: 1996
Main classification: A61M25
IPC codes: A61N1, A61M25