Patent Application
20100094423
Vertebral implants are often used in the surgical treatment of spinal disorders such as disc herniations, scoliosis, degenerative disc disease, and other curvature and degenerative abnormalities and fractures. Various types of treatments can be used. In some cases, spinal fusion is indicated to inhibit relative motion between vertebral members. In other cases, dynamic implants are used to preserve motion between vertebral members. For such treatments, flexible implants may be attached between two or more vertebrae in any one or combination of anterior, lateral, postero-lateral or posterior side applications to the vertebrae. In other procedures, flexible implants are positioned in the spinal disc space. In still other procedures, flexible implants are secured between at least two anatomical locations in a patient.
Flexible implants can be tensioned prior to final attachment between the anatomical locations for implantation and to provide the desired stabilization characteristic or other effect. Assessment of the amount of tension in the implant can be difficult to determine in view of the nature of the implant material, its implanted location, and other factors that may prohibit or inhibit assessment of the implant.
Systems and methods for assessment of a tensioned state of a flexible implant are provided. The implant includes at least one observable marker having a first configuration when the implant is relaxed or not tensioned in a desired manner and a second configuration when the implant is tensioned.
According to one aspect, an implant for implantation in a patient includes a flexible body with a relaxed state and a tensioned state where the tensioned state is for implantation between two implantation locations in the patient. The body includes a marker that has a first configuration in the relaxed state when observed from a first direction and a second configuration that differs from the first configuration when the body is in the tensioned state and observed from the first direction.
In another aspect, an implant for implantation in a patient includes a flexible body with a first configuration between opposite ends of the body when in a relaxed state and a second configuration between the opposite ends when in a tensioned state. The tensioned state is for securement between two implantation locations in the patient. The body includes an elongated marker that forms a non-linear band when observed from a first direction and the body is in the first configuration and a straight band when observed from the first direction and the body is in the second configuration.
In another aspect, an implant for implantation in a patient includes a body formed from flexible material for implantation between locations in the patient. The body includes first and second elongated markers with a first configuration when observed from a first direction and with the body in a relaxed state. The first and second markers include a second configuration when observed from the first direction and the body is in a tensioned state. The second configuration provides an indication of the tensioned state to secure the body between the locations.
According to another aspect, a method for securing an implant in a patient comprises: providing the implant with a flexible body including at least one marker that is observable from a first direction relative to the body; securing the body to a first anatomical location in the patient; tensioning the body toward a second anatomical location; observing a configuration of the at least one marker from the first direction when the body is tensioned; comparing the observed configuration to a desired configuration; and securing the body to the second anatomical location when the observed configuration corresponds to the desired configuration.
These and other aspects are further discussed below.
For the purposes of promoting an understanding of the principles of the invention, 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 invention is thereby intended. Any such alterations and further modifications in the illustrated devices and described methods, and any such further applications of the principles of the invention as illustrated herein are contemplated as would normally occur to one skilled in the art to which the invention relates.
Flexible implants are provided from implantation between at least two locations in a patient in a body to provide repair, stabilization, replacement or other function within the body. The flexible implants include a relaxed state prior to implantation and a tensioned state that is desired for securement to the implantation locations in the patient. The body includes at least one marker having a first configuration when observed from a first direction when the body is in a relaxed state. The marker includes a second configuration when observed from the first direction when the body is in the tensioned state to provide an indication to the surgeon that the body is ready for securement to the implantation locations. As used herein, the relaxed state of the implant can include a state where no tension is applied to the implant, or a state where at least some tension is applied to the implant but the applied tension does not achieve a desired tension state.
Various configurations for the implant and at least one marker are contemplated. For example, in
In
In
Implants 10, 110 each are shown with a body 12, 112 that is elongated and, as shown in
It is also contemplated that bodies 12, 112 of implants 10, 110 can be made from elastic material and/or stretches when tensioned. In each of
In still other embodiments, body 12, 112 is not elastic but is flexible so that it assumes a relaxed state and can be tensioned so that it is taut between its ends, and in the tensioned state its length is greater between its ends than when relaxed. In one specific embodiment, the flexible body can stretch so that it lengthens but is inelastic or partially inelastic so that is does not return to its relaxed state when the tension is released. In another specific embodiment, the flexible body is not readily stretched when tensioned but has a substantially fixed length between its ends when tension is applied thereto.
Markers 20, 120, 121 can be made from the same material as the respective body 12, 112 but provided with any suitable means to allow the marker to be observed and distinguished from body 12, 112 by any one or combination of naked eye visualization, x-ray imaging, fluoroscopy, CT scan, MRI imaging, endoscopic, microscopic, or other suitable viewing system or means. In one embodiment, markers, 20, 120, 121 include a color that contrasts with the color of the adjacent portions of body 12, 112 so the markers can be readily distinguished when observed. In another embodiment, body 12, 112 is comprised of radiolucent material and markers 20, 120, 121 are comprised of radiographic material or material with radiographic coatings, particles or segments that can be readily distinguished when observed. In still another embodiment, body 12, 112 is radiographic and markers 20, 120, 121 are radiolucent to provide a negative image of the marker configuration. In one specific embodiment, body 12, 112 is made from woven fibers, and markers 20, 120, 121 are contrasting fibers that are interwoven with the fibers of the body. In another specific embodiment, markers 20, 120, 121 are made from a layer or coating of contrasting color or radiographic material or particles applied to one or more surfaces of body 12, 112.
In
Other procedures contemplate attachment of implant 10, 110 to more than two vertebrae or two vertebrae with one or more vertebrae therebetween. In the illustrated embodiment, fasteners 30, 32 are bone screws that extend through body 12, 112. It is contemplated that fasteners 30, 32 can include any suitable fastening mechanism, including uni-axial screws, multi-axial screws, hooks, clamps, rivets, interference anchors, suture anchors, plates, staples, wires, bands, tacks, adhesives, and interbody devices between vertebrae, for example. The fasteners can extend through implant 10, 110 or implant 10, 110 can be received in an eyelet, receiver, saddle, or other structure of the fastener and secured therein with a set screw, nut, cap, plug, tack, rivet, weld, locking mechanism, or other suitable securing structure.
Implants 10, 110 have application as a surgical orthopedic device that provides advantageous properties to treat bone defects. The device can be used to treat a variety of bone defects including diseased, damaged, and/or fractured bone. The defective bone structures can be the result of damaged, traumatized, and/or diseased bone tissue. Implants 10, 110 can also be employed in the treatment of scoliosis and/or kyphosis. Furthermore, by use of the term “orthopedic device”, it is intended to include within its meaning a device or implant that can be used to treat or repair defective, diseased, and/or damaged tissue of the muscular/skeletal system(s) and can include attaching bone portions together, reinforcing a single unitary bone portion and/or attaching ligaments to one or more bone portions. Furthermore, the devices and methods described herein can be used to treat any type of bone or related tissue including, without limitation, articulating bone and bone joints, long bones, short bones, flat bones, cortical bone tissue, cancellous bone tissue and associated ligaments.
Implants 10, 110 can be fabricated and/or composed of suitable material tailored to treat and repair a variety of muscular/skeletal defects and disorders. Physical characteristics and properties of implants 10, 110 and associated components such as tensile strength, elasticity or stiffness and creep can be varied as desired. In one embodiment, implants 10, 110 are provided to have a tensile strength sufficient to restrain or maintain the attached bone pieces or portions in a desired orientation and/or spacing with each other despite the biomechanical stresses exerted by the muscular/skeletal system during normal activity. The elasticity or stiffness of implant 10, 110 can also be varied for a particular application or treatment. In addition or in the alternative, implants 10, 110 can deform or creep under strain.
Implants 10, 110 can be provided in a variety of sizes, cross-sections, lengths, widths, and shapes. Implants 10, 110 can be substantially cylindrical or a flat, ribbon-like configuration, whether formed of a single fiber or filament or a plurality of fibers or filaments. When provided as a plurality of fibers, the fiber can be arranged and/or fashioned as desired including without limitation, braiding, wounding, parallel, twisting, and weaving (either 2 dimensional or 3 dimensional weaves). Bodies 12, 112 can be provided in multiple layers stacked one upon the other, or in one or more interwoven layers.
Various suitable materials for implants 10, 110 are contemplated, including, without limitation, degradable or resorbable polymeric materials, metal materials, tissue materials, non-resorbable polymeric material, ceramic material, shape memory material, and composites thereof. Implants 10, 110 can also be coated or impregnated with anti-adhesive material that will prevent tissue and vasculature from attaching thereto.
In one specific embodiment, bodies 12, 112 are made from a soft fiber material. Soft fiber material can include polymeric material, such as SPECTRA fiber, nylon, carbon fiber and polyethylene, among others. In another embodiment, implants 10, 110 are made from commercially available ultra high molecular weight polyethylene (UHMWPE). Examples of suitable polymers include DACRON and GORE-TEX. In another embodiment, bodies 12, 112 are made from metal wire mesh. It is contemplated that the wire can be made from stainless steel, cobalt-chrome alloy, titanium, titanium alloy, or nickel-titanium, among others.
In selected embodiments, implants 10, 110 can be provided with markers 20, 120, 121 to exhibit suitable imaging characteristics including a specified radiopacity to enable the marker to be observed under common medical diagnostics imaging techniques. The radiopacity can help ascertain that the implant has been correctly placed and tensioned, and remains in place with the desired tension. In one form, the radiopacity can be provided by incorporating a radio-opaque element into body 12, 112. In one example, markers 20, 120, 121 include radio-opaque fibers or filaments are associated with body 12, 112. The fibers or filaments can be composed of a radio-opaque material such as a metal filament or a polymeric filament that has been impregnated or coated with a radio-opaque material such as a metallic material.
The radio-opaque markers can be provided in a variety of materials. Examples of radio-opaque materials that can be used in the present invention include, without limitation: nitinol, titanium, titanium-vanadium-aluminum alloy, cobalt-chromium alloy, cobalt-chromium-molybdenum alloy, cobalt-nickel-chromium-molybdenum alloy, stainless steel, tantalum, niobium, hafnium, tungsten, gold, silver, platinum, or iridium metals, alloys, and mixtures thereof. The radio-opaque element can be provided as one or more fibers, filaments or strands made from the above material or one or more fibers, filaments, or strands coated or impregnated with one or more of the materials listed above. In another embodiment, the fibers, filaments or strands are coated with barium sulfate. The radiopacity of markers 20, 120, 121 can be indefinite or can be selected to provide radiopacity for a shorter duration.
While the invention 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, and that all changes and modifications that come within the spirit of the invention are desired to be protected.
