The present disclosure broadly concerns tether systems and relates to a system involving a temporary anchorable tether system and method for introducing a medical device through a surgical opening in a body and guiding the position of the device to a desired location. The present disclosure more specifically, but not exclusively, concerns a flexible tether engaged with two elastic anchor members configured to be deployed and anchor into tissue or bone. The system can be useful in orthopedic procedures, and more specifically in procedures correcting spinal injuries or deformities.
In the realm of orthopedic surgery, it is well known to use implants to fix the position of bones. In this way, the healing of a broken bone can be promoted, and malformations or other injuries can be corrected. For example, in the field of spinal surgery, it is well known to place such implants into vertebrae for a number of reasons, including (a) correcting an abnormal curvature of the spine, including a scoliotic curvature, (b) to maintain appropriate spacing and provide support to broken or otherwise injured vertebrae, and (c) perform other therapies on the spinal column.
Additionally, numerous medical procedures have come into common usage for accessing a desired location within the body in a minimally invasive manner to perform a wide variety of diagnostic and therapeutic procedures. Such medical procedures generally involve the use of a medical instrument, such as a small diameter probe as an example, to create a pathway through the skin and tissue to the desired site. In some approaches, a guidewire is then utilized to extend through the skin to the accessed site to enable over-the-wire advancement of therapeutic, diagnostic or surgical devices, including implants or instruments, to the desired location.
It is generally well known to use guidewire or similar systems to advance the implants, or other such medical devices including instruments, to the desired location in bone or tissue. A multitude of systems exist for guiding medical devices to desired locations; however, the systems can be difficult to assemble and secure, and can cause tissue irritation and/or damage to the surrounding area. Therefore, a need exists for improved systems and methods in this area.
For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated devices, and such further applications of the principles of the disclosure as illustrated therein, being contemplated as would normally occur to one skilled in the art to which the disclosure relates.
The present disclosure provides for temporary anchorable tether systems and methods. The systems can include tethers with retaining, elastic anchor members to be placed through holes created in the body by a surgical instrument. The anchor members of the systems provide a substantially blunt profile to the accessed tissue or bone and reduce the likelihood of damage caused by undesired advancement of the system into the tissue or bone. In certain embodiments, the anchor members are composed of a shape memory alloy and are thereby deformable to be received in an outer sleeve and reform to a curved configuration upon deployment from the outer sleeve to anchor into tissue or bone at a desired location. The systems can include a push rod or needle associated with the tether around which various medical devices can be placed, such as instruments and/or implants, to position the devices adjacent the desired location. Methods of assembling and utilizing the systems described herein are also provided.
Generally referring to
Outer sleeve 102 includes a proximal end 102a and a distal end 102b and defines an elongated bore 120 extending therethrough. In certain embodiments, bore 120 is sized to receive rod 108 having tether 106 disposed therein, crimp 110, and anchor hooks 104 and 105 in a deformed position, as will be explained in greater detail. As illustrated, outer sleeve 102 may optionally include a handle portion 122 adjacent proximal end 102a, with bore 120 extending therethrough. In the illustrated embodiment, handle portion 122 is generally increasing in diameter in a direction toward proximal end 102a. However, it should be appreciated that handle portion 122 (if present) can be configured differently than as illustrated. In certain embodiments, outer sleeve 102 is composed of a substantially rigid material. In certain other embodiments, outer sleeve 102 is composed of a substantially flexible material allowing for sufficient flexibility of outer sleeve 102 during positioning in a patient's body. In the illustrated embodiment, outer sleeve 102 includes an elongated tubular shape; however, it should be appreciated that outer sleeve 102 can be sized and shaped differently.
In the illustrated embodiment, there are two anchor hooks 104 and 105 used in conjunction with system 100. In other embodiments, there may be more or less than two elastic anchor members, such as anchor hooks, used with system 100. Additionally, the elastic anchor member(s) used with system 100 can include other appropriate shapes configured for anchoring into bone. In certain embodiments, the configurations of the elastic anchor member(s) reduce the likelihood of damage to surrounding tissue or bone via reducing or eliminating any advancement of the anchor member(s) into the bone or tissue upon use of system 100. Hooks 104 and 105 include proximal ends 104a and 105a and distal ends 104b and 105b, respectively. Additionally, hooks 104 and 105 include elongated portions 126 and 128 adjacent proximal ends 104a and 105a, respectively. Hooks 104 and 105 may further include anchor portions 127 and 129 adjacent distal ends 104b and 105b, respectively. Anchor portions 127 and 129 may have substantially blunt ends (e.g.
In certain embodiments, anchor hooks 104 and 105 are composed of an elastic or pseudoelastic material. Additionally, in certain embodiments, anchor hooks 104 and 105 are composed of a shape memory alloy, such as nickel titanium as an example. It is contemplated that anchor hooks 104 and 105 can be composed of one or more suitable self-expanding materials. Anchor hooks 104 and 105 each include a natural or unstressed curved configuration (see, e.g.,
In the embodiment shown in
Tether 106 includes a proximal end 106a and a distal end 106b. In certain embodiments, tether 106 is composed of a suture material; however, it is contemplated that other appropriate substantially flexible materials may be used as tether 106. As provided above, in certain embodiments, distal end 106b of tether 106 is connected or engaged with proximal ends 104a and 105a of anchor hooks 104 and 105. Tether 106 may include a length sufficient to span from a desired location within the patient's body to outside the patient's body. Additionally, tether 106 may be sized to allow for threading of medial devices such as implants or instruments over the tether to position the medical devices at the desired location.
Rod 108 includes a proximal end 108a and a distal end 108b and defines an elongated bore 130. In certain embodiments, bore 130 is sized and configured to slidably receive tether 106 therein. When system 100 is assembled, distal end 108b is positioned adjacent or abutting crimp 110 such that rod 108 is generally aligned with crimp 110 (as best seen in
Rod 108 may include a window 132 defined therein configured to receive an undeployed length of tether material 133 of tether 106. In certain embodiments, material 133 is looped through window 132 as necessary such that proximal end 106a of tether 106 is substantially aligned with proximal end 108a of rod 108 (as best seen in
Additionally, system 100 may include crimp 110. Crimp 110 includes a proximal end 110a and a distal end 100b and defines an elongated bore 140 therein. Crimp 110 is configured to join anchors 104 and 105 with tether 106 (see, e.g.,
As best illustrated in
System 100 may also include a tether stop 155 (
The assembly of system 100 will be discussed generally with reference to
Additionally, tether 106 may be inserted through bore 130 of rod 108. In certain embodiments, proximal end 106a of tether 106 is inserted through distal end 108b of rod 108. Rod 108 may be advanced over tether 106 to a desired position and/or until distal end 108b of rod 108 is positioned adjacent and abutting proximal end 110a of crimp 110 (as best seen in FIG. 3). In certain embodiments, undeployed length of material 133 of tether 106 can be accessed through window 132 and looped therethrough (as best seen in
Outer sleeve 102 can be engaged with system 100 by inserting proximal end 108a of rod 108 through distal end 102b of outer sleeve 102. Outer sleeve 102 may be advanced over rod 108, crimp 110 and further advanced over anchor hooks 104 and 105 such that anchor portions 127 and 129 elastically deform within bore 120 of outer sleeve 102 (as best seen in
Generally referring to
To treat the condition or injury of the patient, the surgeon obtains access to the surgical site in any appropriate manner, e.g. through incision and retraction of tissues. It is contemplated that system 100 discussed herein can be used in minimally-invasive surgical techniques where the spinal segment is accessed through a micro-incision, a sleeve, or one or more retractors that provide a protected passageway to the area. System 100 discussed herein also has application in open surgical techniques where skin and tissue are incised and retracted to expose the surgical site.
Upon assembly of system 100 as described above, or in other manners as appropriate, system 100 may be used as or similar to a guidewire medical device to provide for the proper advancement and positioning of medical instruments or implants to a desired location within a patient's body. A surgical opening 160 may be made in the patient's body to allow for the insertion and use of system 100 (as best seen in
System 100 may be deployed causing anchor hooks 104 and 105 to substantially anchor into bone at the desired location. In other embodiments, anchor hooks 104 and 105 are anchored into tissue or other parts of the patient's body. In the illustrated embodiment, anchor hooks 104 and 105 are deployed out of bore 120 of outer sleeve 102 via deployment button 112. However, it should be appreciated that other deployment mechanisms may be used with system 100. In the illustrated embodiment, distal end 112b of deployment button 112 contacts proximal end 108a of rod 108. Additionally, elongated portion 154 of deployment button 112 is inserted into bore 120 at proximal end 102a of outer sleeve 102 and advanced to a position where ledge 153 contacts proximal end 102a of outer sleeve 102 (as best seen in
Upon deployment of system 100 and anchoring of hooks 104 and 105 at the desired position, outer sleeve 102 may be retracted from rod 108 (as best seen in
Once access to the surgical site has been obtained and system 100 has been properly deployed and anchored, the surgeon may advance one or more medical devices to a position adjacent the bone, such as vertebrae of a spinal segment that require compression, distraction and/or support in order to relieve or improve their condition. Medical devices such as instruments or implants may be advanced along rod 108, tether 106 and crimp 110 by initially threading proximal end 108a of rod 108 through a cannulation or other such lumen or hole in a selected instrument or implant. In certain embodiments, the outer diameters of the rod 108, tether 106 and crimp 110 are selected and designed in relation to the lumens or holes defined the various medical devices to be used in connection with system 100, so that the medical devices can be advanced over the components as described herein. The selected medical device can then be positioned adjacent anchor portions 127 and 129 of hooks 104 and 105 at the desired location in the patient's body for the necessary medical application. In such embodiments, the configurations of anchor portions 127 and 129 and the use of system 100 may be thought of as a third guidewire configuration, in which one or more medical devices may be advanced to the desired location in the patient's body.
Following use, anchor hooks 104 and 105 may be pulled or withdrawn through the medical device (e.g. cannulated bone screw) used in connection with system 100. Accordingly, anchor portions 127 and 129 elastically deform into the cannulation or lumen of the medical device. In certain embodiments, anchor portions 127 and 129 may reform to their natural curved configurations upon exiting the cannulation of the medical device. In certain other embodiments, anchor portions 127 and 129 may remain anchored into bone or tissue at the desired location. It is contemplated that system 100 may be designed and configured for repeated use with various medical devices. Additionally, in other cases, it is contemplated that system 100 is designed and configured for a single use.
As an example, the medical devices used with system 100 may be bone implant members, such as bone screws. The bone screws may be advanced to the desired accessed location via system 100. In such cases, pilot holes in vertebrae may be made and threaded bone-engaging portions of the screws may be inserted into or otherwise connected to a vertebral body. Bone engaging portions of the screws can be threaded into the vertebrae to a desired depth and/or desired orientation relative to a longitudinal axis of the spinal segment. In certain embodiments, the surgeon or other medical professional can use a driving tool or other similar instrument to advance the screws.
Thus, in general system 100 can deliver and deploy a guidewire for a bone screw or other implants or tools, the guidewire having a flexible and/or shape memory (e.g. Nitinol) anchor to provide a counter traction, preventing the guide wire from being pulled out while being manipulated. In one example, after a hollow drill has bored a hole into bone, the device is placed through the drill bit and into the drilled hole. When the drill bit is removed, sheath tube or sleeve 102 is retracted while push rod 108 is held in place, deploying anchor hooks 104 and 105. Next sleeve 102 is removed completely. Rod 108 is then retracted as well, exposing tether 106 and providing a flexible portion of guide wire (in tether 106) that may be set aside. Crimp 156 in rod 108 along with tether stop 155, in embodiments in which they are provided, prevent rod 108 and tether 106 from being separated from each other, providing a more rigid portion of guide wire to pass through any necessary instruments, tools or implants.
In certain embodiments, one or more of outer sleeve 102, rod 108, crimp 110, and button 112 are composed of biocompatible, metallic materials. However, it should be appreciated that any or all of outer sleeve 102, rod 108, crimp 110, and button 112 can be formed with one or more of a variety of materials. These materials may be rigid, malleable, semi-flexible, or flexible. The material(s) selected for a particular component of system 100 can depend on a number of factors including but not limited to the intended use of the system, as well as its size, shape, and configuration. In general, suitable material(s) will be selected to allow for a certain desired performance and other characteristics, for example, to exhibit a flexibility falling within a desired range and/or to have shape memory, as with anchor hooks 104 and 105.
Suitable biocompatible metallic materials that can be used in one or more components of system 100 include but are not limited to gold, rhenium, platinum, palladium, rhodium, ruthenium, various stainless steels, tungsten, titanium, nickel, cobalt, tantalum, iron, and copper, as well as alloys of these and other suitable metals, e.g., cobalt alloys, a cobalt-chromium-nickel alloy, a nickel-cobalt-chromium-molybdenum alloy, and a nickel-titanium alloy. In certain aspects, an alloy is selected that exhibits desired biocompatibility and includes suitable strength and ductility to perform in accordance with the methods described herein. In certain embodiments, synthetic polymeric materials, including bioresorbable and/or non-bioresorbable plastics may be used to form one or more components of system 100. Further, one or more suitable ceramic materials may be used to form one or more components of system 100. Moreover, it is contemplated that one or more components of system 100 may include a suitable biocompatible coating thereon.
While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. It should be understood that only certain embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.