The present invention may be understood more readily by reference to the following detailed description of the invention taken in connection with the accompanying drawing figures, which form a part of this disclosure. It is to be understood that this invention is not limited to the specific devices, methods, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the claimed invention. Also, as used in the specification including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” or “approximately” one particular value and/or to “about” or “approximately” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment.
The anchor 10 further includes a head portion 16 at a proximal end thereof and a tail or tongue portion 18 extending distally from the head portion 16. The head portion 16 has a base 20 with a receiver 22 extending at a first direction. The tongue 18 of the anchor 10 extends in a second direction, perpendicular to the first direction of the receiver 22. The receiver 22 has a channel 24 for receiving the free end of the tongue 18. The receiver 22 also contains a pawl (not shown).
Preferably, the head portion 16 also includes a gripper 26 permanently affixed to an inner face 28 thereof. The gripper 26 grasps the lead 12, cushions the lead, and secures the lead in place within the anchor 10. Preferably, the gripper 26 is constructed of a biocompatible material that creates a high coefficient of friction between itself and the lead 12 when it is placed against the lead. For example, silicone can be used for the gripper 26, although those skilled in the art will understand that other biocompatible materials could also be employed. Additionally, the gripper 26 can have a generally “L-shape” when the lead 12 is in the open configuration as shown in
Preferably, the tongue portion 18 is a flexible member including a plurality of teeth or barbs 30 on an outer face 32 thereof. The tongue portion 18 is inserted through the channel 24 of the receiver 22 such that the anchor 10 forms a loop that can be tightened against the lead 12. When closed around the lead 12, the tongue 18 forms a U-shaped member with a first leg of the “U” being the part that extends from the base 20 of the head 16 and a second leg of the “U” being part of the tongue 18 inserted in the channel 24 of the receiver 22. The gripper 26 is enclosed within the U-shaped member and compressed against the lead 10 when tightened by pulling the free end of the tongue 18 through the channel 24. The pawl engages the teeth 30 of the tongue portion 18 and allows the anchor 10 to be tightened or pulled through the receiver in the forward direction, but not loosened or pulled through the receiver in the rearward direction. The teeth 30 and pawl prevent loosening after the anchor 10 is tightened to maintain compression. Thus, the receiver 22 and tongue 18 together form a ratchet to prevent retraction of tongue from receiver.
The excess tongue section 18 of the anchor 10 comes off of the head portion 16 at an offset of 90 degrees to minimize stresses on the anchor where it connects to the ratchet while making a tight circle or loop. Preferably, the excess tongue section 18 is trimmed from the anchor.
The anchor 10 preferably also includes a suture ring 34 permanently affixed to the outer surface of the head portion 16 generally behind the gripper 26. The ring 34 serves as a loop to secure the anchor 10 to the adjacent tissues using a suture. Preferably, the ring 34 is constructed of a biocompatible metal, such as stainless steel or titanium, such that the ring can be viewed with an x-ray or other imaging technology. Alternatively or additionally, the ring 34 (or another portion of the anchor 10) may include a radio-opaque marker for identifying the location of the ring, and hence the location of the lead, in the body of the patient using conventional imaging technology. Identifying the location of the ring and lead can be useful both when implanting the lead and anchor and when performing additional revision surgeries of the stimulator system.
A tool similar to a cable tie gun (not shown) can be used to tighten the anchor 10 to a preset tightness that will avoid damage to the lead 12 while still holding it securely. The tool also serves to cut off excess length of the tongue 18. Preferably, the tool is reusable, and thus is constructed of materials that are autoclavable or otherwise capable of sterilization. For example, the tool can be constructed of stainless steel. Alternatively, the tool is disposable. The tool preferably applies a consistent, user-independent desired tension within a predetermined safe and effective range. For example, the tool can employ a precisely calibrated spring that controls how much tension is applied by the gun, although those skilled in the art will understand that various other methods or mechanisms to control the amount of tension can be used as well.
In an example method of operation, a practitioner makes an incision on a patient's back and implants a lead 12, such as a percutaneous lead or a surgical lead for spinal cord stimulation or an intrathecal lead for drug delivery, through the incision according to standard medical procedures. Once implanted, the practitioner places the anchor 10 around the lead 12 such that the gripper 26 loosely grips the lead and the tongue portion 18 is inserted into the channel 24 of the receiver 22. Preferably, the anchor 10 is positioned and secured in an area located near the incision, as shown in
While the invention has been described with reference to preferred and example embodiments, it will be understood by those skilled in the art that a variety of n the scope of the invention, as defined by
This application claims priority to U.S. Provisional Patent Application Ser. No. 60/789,970, filed Apr. 6, 2006, which is hereby incorporated herein by reference in its entirety for all purposes.
Number | Date | Country | |
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60789970 | Apr 2006 | US |