News Column

Patent Issued for Strain Relief Apparatus for Use with Implantable Medical Lead

May 28, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Mehdizadeh, Bruce R. (Savage, MN); Kern, Michael J. (St. Louis Park, MN), filed on April 11, 2011, was published online on May 13, 2014.

The assignee for this patent, patent number 8721661, is Medtronic, Inc. (Minneapolis, MN).

Reporters obtained the following quote from the background information supplied by the inventors: "Implantable medical leads are used in conjunction with electrical medical devices for a variety of purposes, such as delivery of therapy or monitoring of a condition. Implantable medical leads are typically flexible along their length, but are limited in extension by the length of the lead. Due to their limited extensibility, implantable medical leads may be tensioned by movements of the body in which they are implanted. Such tensioning of the lead may cause the lead to limit movement of the patient's body or may cause the lead to migrate or to be pulled from its intended location within the body.

"To overcome such problems, extra lead length or slack can be provided to allow for freedom of movement on the part of the patient and little movement of the lead distal portion from or within its intended location. In some cases, loops or coils are introduced in the lead as the lead is being implanted to provide for strain relief. However, as different implanting physicians may form such loops or coils in different manners, the amount and effectiveness of such strain relief may be variable. Further, tissue may adhere to or grow in between extra lead length or slack or loops or coils limiting their effectiveness to provide strain relief."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "This disclosure, among other things, describes an extensible implantable medical device for providing strain relief to at least a portion of an implantable medical lead. The extensible device may be manufactured to specifications that may result in reproducible and reliable strain relief when the extensible device is disposed about at least a portion of a lead. Thus, the strain relief and resulting extensibility of the lead may be readily controlled within reproducible ranges.

"In various embodiments, the extensible implantable medical device includes a body defining a lumen extending through the body. The lumen is configured to receive at least the portion of the implantable medical lead. The body includes a non-rectilinearly shaped portion. The non-rectilinearly shaped portion has a first shape spanning a first distance in a relaxed state. The non-rectilinearly shaped portion has a second, more rectilinear, shape spanning a second distance when subjected to a stretching force. The second distance is greater than the first distance. The non-rectilinearly shaped portion returns to the relaxed first shape upon release of the stretching force and is configured to assume the first shape when the lead is inserted into the lumen and no load is placed on the lead or the shaped body portion.

"In some embodiments, at least a portion of the body has a radially expandable inner diameter defined by the lumen. The inner diameter of the portion of the body, in a relaxed state, is configured to be less than the outer diameter of the portion of the lead that the lumen is configured to receive. The inner diameter of the portion of the body is configured to be radially expandable to a diameter greater than the outer diameter of the portion of the lead that the lumen is configured to receive to allow insertion of the lead into the lumen. The inner diameter of the portion of the body is biased towards the relaxed state and is configured to grippingly engage the portion of the lead when the lead is inserted into the lumen. Accordingly, longitudinal movement of the lead relative to the extensible device may be prevented or inhibited.

"In some embodiments, the extensible device includes an anchor region for retaining the device in tissue when the device is implanted in a patient. The anchor region may include suture holes; barbs, tines; or the like for such purposes. In some cases, the body of the extensible device forms at least a portion of the anchor portion, and the lumen defined by the body extends through the anchor region.

"One or more extensible medical devices described herein may be included in kits with one or more leads that the extensible devices are configured to receive and to impart strain relief. The extensible devices may be preloaded on the leads. In some cases, the kits include a tool for facilitating placement of the extensible devices about the lead. The tool may have an elongate member having a distal opening and a lumen extending proximally in the elongate member from the distal opening. The lumen of the elongate member is configured to slidably receive at least a portion of a lead. The lumen of the extensible device is configured to receive the elongate member of the tool. Thus, the extensible device may be placed about the elongate member of the tool, the lead may be inserted in the lumen of the elongate member, and the elongate member may be withdrawn over the lead as the extensible device is maintained in relative longitudinal orientation with the lead to dispose the extensible device about the lead.

"In addition to the various advantages described above, other advantages of one or more embodiments of the methods and systems described herein will be apparent to those of skilled in the art upon reading the following detailed description."

For more information, see this patent: Mehdizadeh, Bruce R.; Kern, Michael J.. Strain Relief Apparatus for Use with Implantable Medical Lead. U.S. Patent Number 8721661, filed April 11, 2011, and published online on May 13, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=106&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=5269&f=G&l=50&co1=AND&d=PTXT&s1=20140513.PD.&OS=ISD/20140513&RS=ISD/20140513

Keywords for this news article include: Medtronic Inc.

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Source: Journal of Engineering


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