Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical energy applicator
Reexamination Certificate
2000-12-04
2001-11-27
Evanisko, George R. (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical energy applicator
C606S108000
Reexamination Certificate
active
06324434
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to lead locking devices and methods for locking onto a lead, and more particularly to lead locking devices and methods for locking onto and removing a lead from a patient's body, such as a pacemaker lead.
2. Description of Related Art
Various medical procedures attach wire-like devices to internal portions of a person's body, such as an electrical lead for a pacemaker or a catheter. Pacemaker leads are electrically conducting wires which run to an electrode that is attached to an inner wall of a person's heart. Pacemaker leads are typically a coil of wire enclosed in an outer cylindrical sheath of electrically insulating material. The coil of wire usually leaves a hollow space running down the center of the pacing lead (a “lumen”).
Pacing leads are usually implanted with the intention that they will remain in the patient for several years. During such time, fibrous tissue grows over the electrode and portions of the lead. Pacing leads are often provided with additional barb-like structures or a corkscrew type of structure to encourage adhesion to the inner wall of the patient's heart.
Pacing leads sometimes fail or it is sometimes desirable to place an electrode at a different position from a previous position. It is then necessary to determine what should be done with the unused pacing leads. Both the removal of a pacing lead and leaving it in the patient entail associated risks. Leaving the pacing lead in the patient can increase the chances of infection, interfere with the additional pacing leads, or cause additional complications. On the other hand, removing pacing leads can cause severe, and possibly fatal, damage to the patient's heart.
Numerous devices have thus been developed that can be inserted into the lumen of a pacing lead and attach to the pacing lead close to the electrode in order to apply traction to the end of the lead close to the electrode. A series of patents to Goode et al (U.S. Pat. Nos. 4,943,289; 4,988,347; 5,011,482; 5,013,310; and 5,207,683) disclose various devices which attach to the pacing lead at a localized region close to the electrode. Peers-Trevarton (U.S. Pat. No. 4,574,800), Hocherl et al (U.S. Pat. No. 5,549,615) and McCorkle (U.S. Pat. Nos. 4,471,777 and 4,582,056) disclose similar devices which attach to a pacing lead close to the electrode. However, all of these devices have a disadvantage that they attach to the pacing lead in a localized area. Applying traction to the pacing lead and/or pacing lead removing devices according to the prior art can lead to the pacing lead's becoming distorted and/or breaking before the pacing lead is successfully removed from the patient. In addition, the prior art devices rely on either a form of entanglement with the coiled wire of the pacing lead, or some form of local distortion to the coil of the pacing lead in order to maintain a firm grip with the pacing lead removing apparatus while traction is applied to the apparatus. Consequently, this makes it difficult or impossible to remove a conventional device from the pacing lead in order to abort or restart the pacing lead removing procedure.
The expandable portions of the conventional devices also make it difficult or impossible to use other lead removing equipment and procedures in conjunction with those devices. For example, a substantially cylindrical and flexible catheter which has a central lumen is often slid over the pacing lead such that the pacing lead passes through the lumen of the catheter and the leading edge of the catheter is used to free fibrous growth from the pacing lead. Laser catheters are also known to slide over a pacing lead in which laser light is transmitted along the catheter in order to cut away fibrous tissue as the laser catheter is advanced along the pacing lead. Consequently, it is also desirable to have a pacing lead removing device which can attach internally to the pacing lead so as not to obstruct a catheter or laser catheter which may be used in conjunction with the pacing lead removing device.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide a lead locking device which is insertable into a lumen of a lead and which engages and forms a grip with an extended portion of the inner region of the lead.
It is another object of this invention to provide a lead locking device which is insertable into a lumen of a lead and which engages and forms a grip with an extended portion of the inner region of the lead including at least a proximal portion.
It is another object of this invention to provide a lead locking device which is insertable into a lumen of a lead and engages the lead substantially along the entire length of the lead to form a grip with the lead.
It is another object of this invention to provide a lead locking device which is compatible for use in conjunction with a catheter threaded over the outside surface of the lead.
It is another object of this invention to provide a method of removing a pacing lead by attaching a lead locking device to an extended portion of a lead within the lumen of the lead.
It is another object of this invention to provide a method of removing a lead from a patient's body by attaching a lead locking device along substantially the entire length of a lead.
The above and related objects of this invention are realized by providing a lead locking device that has a lead engaging member extending along a longitudinal direction and defining a lumen therein. A mandrel is disposed in the lumen and attached to the distal end of the lead engaging member such that the mandrel extends substantially along the entire length of the lumen and protrudes beyond a proximal end of the lead engaging member. The lead engaging member has a first configuration in which it is slid into a lumen defined by a lead, such as a pacing lead. Preferably, the lead engaging member is sufficiently long to extend along at least about 30% of, and more preferably, substantially along the entire length of the pacing lead. When the lead engaging member extends along less than substantially the entire length of the pacing lead, it is preferable for the pacing lead to engage at least a distal portion and a proximal portion of the pacing lead; however, the scope and spirit of the invention includes generally engaging at least about 30% of the lead engaging member. The lead engaging member has a second configuration in which it engages the lead substantially along the entire length of the lumen of the lead. This engagement of the lead engaging member to the lead forms a connection or lock to the lead. By engaging the lead substantially for the entire length, the tractional force can be distributed along the lead, thus reducing distortion and breakage of a lead during the lead removal process.
The general concept of the lead engaging member engaging the pacing lead along substantially the entire length of the lead may be realized in a great variety of embodiments. In some preferred embodiments, the lead engaging member is an elastic sheath which is stretched in the first configuration and substantially relaxed in the second configuration. In a first preferred embodiment, the lead engaging member is a braided sheath of wires. Preferably, the wires are flat wires which have a rectangular cross-sectional shape. In a second preferred embodiment, the lead engaging member is a sheath of elastic material, such as rubber.
Generally, the lead engaging member has a narrower maximum diameter in the first configuration than in the second configuration. The greater diameter in the second configuration results in the lead engaging member gripping the lead from within the lumen due to frictional or other contact forces with the wall of the lumen.
The lead locking device according to the preferred embodiments has a mechanism that holds the lead engaging member in a stretched configuration. However, the general concepts of the invention are not limited to having such a mechanism to hold the lead engaging
Coe Michael Sean
Diaz Cesar
Harlan Kenneth D.
Plasket Thomas E.
Evanisko George R.
Pillsbury & Winthrop LLP
Spectranetics Corporation
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