Surgery – Diagnostic testing – Flexible catheter guide
Reexamination Certificate
2000-09-12
2004-10-19
Truong, Kevin T. (Department: 3762)
Surgery
Diagnostic testing
Flexible catheter guide
Reexamination Certificate
active
06805675
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to implantable leads and catheters and more particularly to mechanisms for deflecting implantable leads and catheters to assist in guiding them through the vascular system.
Over the years, quite a number of mechanisms have been disclosed and employed to deflect catheters and implantable leads. These have taken the form of deflectable guidewires and deflectable stylets, typically operable from the proximal end of the lead or catheter, which controllably impart a curve to the distal portion of the catheter. One group of devices comprise deflectable stylets or guidewires which employ a straight, tubular outer member with a curved inner member, the inner and outer members movable relative to one another. Examples of this type of deflection mechanism are disclosed in U.S. Pat. No. 4,136,703 issued to Wittkampf and U.S. Pat. No. 5,728,148 issued to Bostrom et al. Alternatively, deflection devices employing a curved outer member and a relatively straight inner member are also known to the art, as disclosed in U.S. Pat. No. 4,676,249 issued to Arenas and U.S. Pat. No. 5,040,543 issued to Badera et al. In devices of both types, the relative position of the inner member with respect to the outer member determines the degree to which the curved member (inner or outer) is allowed to display its preset curvature.
A more commonly employed approach to providing controllable deflection employs a generally straight outer member and a tension or push wire located within the outer member that, upon advancement or retraction, causes the outer member to bend. Examples of such deflection mechanisms can be found in U.S. Pat. No. 4,815,478 issued to Buchbinder et al., and U.S. Pat. No. 4,940,062 issued to Hampton et al. Particularly in the context of deflectable stylets intended for use in conjunction with implantable medical leads such as pacing and cardioversion leads, steerable stylets employing this third type of deflection mechanism are disclosed in U.S. Pat. No. 5,662,119 issued to Brennan et al., U.S. Pat. No. 5,170,787 issued to Lindegren, and U.S. Pat. No. 5,327,906 issued to Fideler et al, all of which are incorporated herein by reference in their entireties.
Additional deflectable stylet designs are disclosed in the above-cited Bauman and Greene et al applications. In these designs, the handle for the stylet is provided with a rotatable knob which, like in the above-cited Fideler patent, is employed to curve and straighten the stylet. This knob is provided with a distally facing recess at its distal end. The connector assembly of the lead is located in this distally facing recess.
In conjunction with the use of deflectable stylets to implant leads having screw-in fixation mechanisms which require rotation of the connector pin to screw the fixation mechanism into body tissue, it is also known to employ a spinner ball or clamp to rotate the connector pin, as described in the Pacesetter Locator Steerable Stylet User Manual for the Pacesetter Model 4036 Steerable Stylet. The spinner ball, as described, however, does not allow compensation for variations in lead length or allow for ready adjustment of the position of the stylet within the lead body. For example, the spinner ball mechanism must be disconnected from the handle to allow for retraction of the stylet tip within the lead to reduce the stiffness at the lead tip.
SUMMARY OF THE INVENTION
The present invention is directed toward providing a deflectable stylet system particularly optimized for use in conjunction with a lead of the type having a fixation helix, in which the fixation helix is screwed into body tissue by rotation of the connector pin of the lead. In particular, the invention is intended to provide a deflectable stylet system that allows for differences in length from lead to lead and also provides an easy mechanism for adjusting the position of the stylet within the lead body.
The present invention accomplishes the above results by means of an attachment to the stylet handle which includes an affixation device that may be connected to the connector pin of the lead. In one embodiment, the affixation device may be a threaded device such as a screw. In another embodiment, the affixation device is a pushbutton clevis having an unlocked position for receiving the lead, and a locked position for rigidly coupling the lead to the attachment.
When the attachment is coupled to the lead, the attachment may be rotated to screw the fixation helix into body tissue, configured such that the knob and the lead to which it is attached may readily be moved longitudinally relative to the remainder of the deflectable stylet handle. In a preferred embodiment, the attachment includes a knob with a recess at its distal end for engaging the connector pin of a lead and an elongated tubular extension at its proximal end, slidably inserted into a corresponding distally facing recess in a deflectable stylet handle. In a more preferred embodiment, the distally facing recess in the stylet handle is formed within the spinner or knob of a deflectable stylet handle generally as disclosed in the above cited Greene et al application. The proximally directed extension on the attachment's knob allows for it to be moved longitudinally relative to the stylet handle, in turn allowing for longitudinal movement of the lead relative to the deflectable stylet.
In one preferred embodiment, the deflectable stylet assembly is also provided with a tubular pin, mounted around the proximal portion of the flexible stylet and mounted in fixed longitudinal relationship with the stylet handle. This tubular pin may engage the interior of the proximally directed tubular extension of the attachment, providing for an additional mechanism to allow longitudinal movement of the attachment knob relative to the deflectable stylet handle, while retaining appropriate alignment of the attachment knob and stylet handle to allow for rotation of the attachment knob. In some embodiments, a bushing may be provided within the attachment to facilitate the free rotation of the attachment around the tubular pin. The attachment may be slip-fit to the tubular pin in a manner that provides for controlled longitudinal repositioning of the attachment with respect to the stylet assembly. The attachment may also be adapted to rigidly couple to the tubular pin at predetermined positions on the pin.
REFERENCES:
patent: 4136703 (1979-01-01), Wittkampf
patent: 4488561 (1984-12-01), Doring
patent: 4572605 (1986-02-01), Hess
patent: 4676249 (1987-06-01), Arenas et al.
patent: 4815478 (1989-03-01), Buchbinder et al.
patent: 4922607 (1990-05-01), Doan et al.
patent: 4940062 (1990-07-01), Hampton et al.
patent: 5040543 (1991-08-01), Badera et al.
patent: 5170787 (1992-12-01), Lindegren
patent: 5327906 (1994-07-01), Fideler
patent: 5473812 (1995-12-01), Morris et al.
patent: 5662119 (1997-09-01), Brennen et al.
patent: 5728148 (1998-03-01), Bostrom et al.
patent: 6263224 (2001-07-01), West
patent: 6616628 (2003-09-01), Hayzelden
Clemens William J.
Gardeski Kenneth C.
Odegard Jeremy John
Poor Corinne A. G.
Medtronic Inc.
Soldner Michael C.
Truong Kevin T.
Wolde-Michael Girma
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