Patent Application
20110118740
The embodiments disclosed herein relate to minimally invasive orthopedic procedures, and more particularly to intramedullary implants having variable fastener placement and methods of using same for fixation of fractured bone segments.
Bone is a living tissue and plays a structural role in the body. A bone fracture is a medical condition in which a bone has cracked or broken. While many fractures are the result of high force impact or stress, bone fracture can also occur as a result of certain medical conditions that weaken the bones, such as osteoporosis, certain types of cancer or osteogenesis imperfecta. The average person sustains two to three fractured bones during the course of a lifetime. Fracture repair is the process of rejoining and realigning the ends of broken bones. Currently there are several approaches to repairing, strengthening and supporting a fractured bone.
Intramedullary implants having variable fastener placement and methods of using same are disclosed herein. According to aspects illustrated herein, there is provided an intramedullary implant that includes a non-compliant expandable portion having an outer surface and an inner cavity, wherein a hardened light-sensitive liquid is contained within the inner cavity of the expandable portion; and at least one fastener penetrating the expandable portion at a first location along the outer surface of the expandable portion and into the inner cavity of the expandable portion, wherein the at least one fastener penetrates the expandable portion at a user selected location anywhere along a length of the expandable portion, and wherein the at least one fastener penetrates the expandable portion at any angle relative to the expandable portion. In an embodiment, an intramedullary implant of the present disclosure may be used to align and stabilize fractures of a long bone.
According to aspects illustrated herein, there is provided an intramedullary implant that includes a non-compliant expandable portion having an outer surface and an inner cavity, wherein the non-compliant expandable portion is sized for placement into a medullary canal of a bone; a hardened light-sensitive liquid disposed within the inner cavity of the expandable portion; and at least one fastener penetrating the expandable portion at a first location along the outer surface of the expandable portion and into the inner cavity of the expandable portion, wherein the expandable portion, when placed into a medullary canal of a bone, is configured to accept the at least one fastener at a location anywhere along a length of the expandable portion, and at any angle relative to the expandable portion and to any penetration depth.
According to aspects illustrated herein, there is provided an intramedullary implant kit for use in a medullary canal of a long bone that includes a unit dose of a light-sensitive liquid; a non-compliant expandable portion releasably mounted on an insertion catheter, wherein the insertion catheter has an inner void for passing the light-sensitive liquid to the expandable portion, and an inner lumen; and at least one fastener.
According to aspects illustrated herein, there is provided a method for stabilizing a fractured bone that includes penetrating the fractured bone to gain access to a medullary cavity of the fractured bone; inserting an expandable portion into the medullary cavity of the fractured bone; introducing a light-sensitive liquid monomer into the expandable portion so as to expand the expandable portion, wherein the light-sensitive liquid monomer is introduced into the expandable portion through at least one lumen of an insertion catheter releasably connected to the expandable portion, hardening the light-sensitive liquid monomer within the expandable portion so as to polymerize the light-sensitive liquid monomer; separating the insertion catheter from the expandable portion; and stabilizing the fractured bone, wherein the at least one fastener extends through an outer surface of the fractured bone, through an inner surface of the fractured bone, and into the expandable portion at any location along a length of the expandable portion, at any angle and to any penetration depth relative to the expandable portion.
The presently disclosed embodiments will be further explained with reference to the attached drawings, wherein like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the presently disclosed embodiments.
While the above-identified drawings set forth presently disclosed embodiments, other embodiments are also contemplated, as noted in the discussion. This disclosure presents illustrative embodiments by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of the presently disclosed embodiments.
The embodiments disclosed herein relate to minimally invasive orthopedic procedures, and more particularly to intramedullary implants having variable fastener placement and methods of using same for fixation of fractured bone segments. In an embodiment, an intramedullary implant includes a thin-walled, non-compliant, expandable portion having an inner lumen filled with a light-sensitive liquid which has been hardened in situ and at least one fastener having a proximal end and a distal end, wherein the distal end of the fastener penetrates an outer surface of the expandable portion at a user selected insertion spot. In an embodiment, after the distal end of the fastener penetrates the outer surface of the expandable portion, the distal end of the fastener resides within the inner lumen of the expandable portion.
In an embodiment, an intramedullary implant includes a non-compliant expandable portion having an outer surface and an inner cavity, wherein the non-compliant expandable portion is sized for placement into a medullary canal of a bone, a hardened light-sensitive liquid disposed within the inner cavity of the expandable portion, and at least one fastener penetrating the expandable portion at a first location along the outer surface of the expandable portion and into the inner cavity of the expandable portion, wherein the expandable portion, when placed into a medullary canal of a bone, is configured to accept the at least one fastener at a location anywhere along a length of the expandable portion, and at any angle relative to the expandable portion.
In an embodiment, after the distal end of the fastener penetrates the outer surface of the expandable portion, the distal end of the fastener penetrates the outer surface of the expandable portion at a different location than the insertion spot. The fasteners can be inserted at any point along the expandable portion and without regard to orientation, which may allow a surgeon to avoid not only important ligaments/muscle but also avoid critical nerve branches. In an embodiment, no guidance is required to insert the fastener into the expandable portion.
In an embodiment, an intramedullary implant includes a non-compliant expandable portion having an outer surface and an inner cavity, wherein a hardened light-sensitive liquid is contained within the inner cavity of the expandable portion; and at least one fastener penetrating the expandable portion at a first location along the outer surface of the expandable portion and into the inner cavity of the expandable portion, wherein the at least one fastener penetrates the expandable portion at a user selected location anywhere along a length of the expandable portion, and wherein the at least one fastener penetrates the expandable portion at any angle relative to the expandable portion. In an embodiment, an intramedullary implant of the present disclosure is sufficiently designed to induce compression of bone segments during bone fixation. In an embodiment, when the at least one fastener penetrates the hardened expandable portion, compression at the fracture site is induced by angling the fastener to pull the hardened expandable portion and the bone together.
In an embodiment, locking (via a fastener) an intramedullary implant proximally and distally provides rotational and axial stability to the intramedullary implant. When setting a broken bone, the fractured fragments should be aligned with each other so that the fractured edges will mate properly for healing. Intramedullary implants stabilize the fractured fragments and hold them in place for healing. If the intramedullary implant is loose or is able to wobble inside the medullary cavity of the fractured bone, however, the fractured fragments can rotate or shift axially, causing, for example, a rotational displacement about the fracture line, a gap or other discontinuity. In an embodiment, an intramedullary implant of the present disclosure provides rotational stability and resistance to axial migration. As will be described in detail below, the diameter of an intramedullary implant of the present disclosure can be customized during the implantation of the device to achieve a tight fit between the implant and the medullary cavity of the fractured bone. In embodiment, an intramedullary implant of the present disclosure is configured to conform to the internal diameter of the medullary cavity of the fractured bone as well as the curvature of the cavity. In an embodiment, the frictional force on the implant will prevent the bone from rotating on the implant. In an embodiment, the implant may be secured to the bone using fasteners at user selected locations. User selected locations for fastener holes may allow for dynamic compression and shortening while still maintaining rotational stability of the fractured fragments. Because the fasteners may be placed at a short distance from each other, the torsion or torque exerted by the bone on the implant can also be minimized. The fasteners can be placed closer to the proximal/distal sides of the fractured bone, and by doing so, the torque/rotational forces that can be imparted are reduced. The placement of the fasteners closer to the fracture site is patient specific If multiple fasteners are used, the position, depth of penetration and orientation of each fastener relative to a neighboring fastener is independent.
In an embodiment, an intramedullary implant of the present disclosure may be used to align and stabilize fractures of a long bone. In an embodiment, an intramedullary implant of the present disclosure may be used to align and stabilize a long bone including bones selected from the group consisting of metacarpal, femur, tibia, fibula, humerus, ulna, radius, metatarsals, phalanx, phalanges, ribs, spine, vertebrae, clavicle and other bones and still be within the scope and spirit of the disclosed embodiments.
Conventional fixation devices include wires, plates, rods, pins, nails, and fasteners to support the fractured bone directly, as well as the addition of bone cement mixtures, or bone void fillers to the fractured bone. One common device, the intramedullary rod or nail, is implanted into the bone marrow canal in the center of the long bones of the extremities, such as the femur or the tibia. These intramedullary rods are able to share the load with the bone, rather than support the bone entirely, thus allowing patients to use the extremity more quickly. In these conventional fixation devices, the effect is biologic healing, wherein a device has the strength of the bone, not more than the bone, therefore sharing the load across the fracture to stimulate healing.
The use of conventional intramedullary rods results in several disadvantages to both the patient and the staff. For example, intramedullary rods typically contain predrilled holes which are located throughout the rod. To secure an intramedullary rod in place, fasteners, nails or pins are inserted into these holes. Numerous methods and apparatus have been developed to place locking fasteners across both a fractured bone and an implanted intramedullary nail. Nail locking is currently made using either mechanical aiming arms or X-ray guidance. These X-ray guided procedures require the X-ray source positioned such that the X-ray beam is parallel to the axis of the nail hole, increasing X-ray exposure to the patient and the staff. Another disadvantage of the predrilled holes is that the fasteners, nails and pins must be precisely inserted into the holes in order for the rod to be secured. This requires having an aiming system in place to “find” the hole. Moreover, predrilled holes may not be situated in the best locations for securing the rod. As such, fasteners, nails and pins may need to be inserted in sub-optimal places.
In an embodiment, a flexible insertion catheter may be used for insertion of an expandable portion component of an intramedullary implant of the present disclosure. Generally, such insertion catheters may include an elongated shaft with a proximal end and a distal end, and a longitudinal axis therebetween.
In an embodiment, a separation area is located at the junction between the expandable portion and the insertion catheter. The separation area may have a stress concentrator. The stress concentrator may be a notch, groove, channel or similar structure that concentrates stress in the separation area. The stress concentrator of the separation area may be notched, scored, indented, pre-weakened or pre-stressed to direct separation of the expandable portion from the elongated shaft of the insertion catheter under specific torsional load. The separation area ensures that there are no leaks of the light-sensitive liquid from the insertion catheter and/or the expandable portion. The separation area seals the expandable portion and removes the insertion catheter by making a break at a known or predetermined site (e.g., a separation area). The separation area may be various lengths and up to about an inch long. In an embodiment, when torque (twisting) is applied to the insertion catheter the shaft of the insertion catheter separates from the expandable portion. The twisting creates a sufficient shear to break the residual hardened light-sensitive and create a clean separation of the expandable portion/insertion catheter interface. In an embodiment, the expandable portion is cut from the insertion catheter using a cutting device.
In an embodiment, the insertion catheter may include multiple inner lumen or voids. For example, as shown in
Light-sensitive liquid can be introduced into the proximal end 112 of the insertion catheter 101 and passes through the inner void 210 of the insertion catheter 101 up into the inner cavity 235 of the expandable portion 200 to move the expandable portion from a deflated state to an inflated state when the light-sensitive liquid is delivered to the expandable portion, in order to form a rigid orthopedic stabilizer. In an embodiment, the light-sensitive liquid is provided as a unit dose. As used herein, the term “unit dose” is intended to mean an effective amount of light sensitive liquid adequate for a single session. By way of example, a unit dose of a light sensitive liquid of the present disclosure for expanding an expandable portion of the present disclosure may be defined as enough light-sensitive liquid to expand the expandable portion so that the expanded expandable portion realigns a fractured bone and/or secures the bone back into an anatomical position. The amount of realigning may vary somewhat from user to user. Thus, a user using a unit dose may have excess light-sensitive liquid left over. It is desirable to provide enough light-sensitive liquid that even the above-average user will have an effective amount of realignment. In an embodiment, a unit dose of a light-sensitive liquid of the present disclosure is contained within a container. In an embodiment, a unit dose of a light-sensitive liquid of the present disclosure is contained in an ampoule. In an embodiment, the expandable portion is sufficiently shaped to fit within a space or a gap in a fractured bone. In an embodiment, the light-sensitive liquid can be delivered under low pressure via a standard syringe attached to the port 135. The light-sensitive liquid can be aspirated and reinfused as necessary, allowing for adjustments to the expandable portion. These properties allow a user to achieve maximum fracture reduction prior to activating a light source and converting the liquid monomer into a hard polymer.
A light-conducting fiber communicating light from the light source can be introduced into the proximal end 112 of the insertion catheter 101 through port 115 and passes within an inner lumen of the insertion catheter 101 up into the expandable portion. In an embodiment, the light source emits frequency that corresponds to a band in the vicinity of 390 nm to 770 nm, the visible spectrum. In an embodiment, the light source emits frequency that corresponds to a band in the vicinity of 410 nm to 500 nm. In an embodiment, the light source emits frequency that corresponds to a band in the vicinity of 430 nm to 450 nm. The light-sensitive liquid remains a liquid monomer until activated by the light-conducting fiber (cures on demand). In an embodiment, the liquid monomer is exposed to an appropriate frequency of light and intensity to cure the monomer inside the expandable portion and form a rigid structure. In an embodiment, the liquid monomer is exposed to electromagnetic spectrum that is visible (frequency that corresponds to a band in the vicinity of 390 nm to 770 nm). In an embodiment, the liquid monomer is radiolucent, which permit x-rays to pass through the liquid monomer. Radiant energy from the light source is absorbed and converted to chemical energy to quickly (e.g., cured in about five seconds to about five minutes) polymerize the monomer. This cure affixes the expandable portion in an expanded shape. A cure may refer to any chemical, physical, and/or mechanical transformation that allows a composition to progress from a form (e.g., flowable form) that allows it to be delivered through the inner void in the insertion catheter 101, into a more permanent (e.g., cured) form for final use in vivo. For example, “curable” may refer to uncured composition, having the potential to be cured in vivo (as by catalysis or the application of a suitable energy source), as well as to a composition in the process of curing (e.g., a composition formed at the time of delivery by the concurrent mixing of a plurality of composition components).
Additives may be included in light-sensitive liquids, including, but not limited to, drugs (for example, antibiotics), proteins (for example, growth factors) or other natural or synthetic additives (for example, radiopaque or ultrasonically active materials). In an embodiment, the viscosity of the light-sensitive liquid has a viscosity of about 1000 cP or less. In an embodiment, the light-sensitive liquid has a viscosity ranging from about 650 cP to about 450 cP. The expandable portion may be inflated, trial fit and adjusted as many times as a user wants with the light-sensitive liquid, up until the light source is activated, when the polymerization process is initiated. Because the light-sensitive liquid has a liquid consistency and is viscous, the light-sensitive liquid may be delivered using low pressure delivery and high pressure delivery is not required, but may be used.
In an embodiment, a contrast material may be added to the light-sensitive liquid without significantly increasing the viscosity. Contrast materials include, but are not limited to, barium sulfate, tantalum, or other contrast materials known in the art. The light-sensitive liquid can be introduced into the proximal end of the insertion catheter and passes within the inner void of the insertion catheter up into an inner cavity of the expandable portion to change a thickness of the expandable portion without changing a width or depth of the expandable portion. In an embodiment, the light-sensitive liquid is delivered under low pressure via the syringe attached to the port. The light-sensitive liquid can be aspirated and reinfused as necessary, allowing for thickness adjustments to the expandable body prior to activating the light source and converting the liquid monomer into a hard polymer. Low viscosity allows filling of the intramedullary implant through a very small delivery system.
One or more radiopaque markers or bands may be placed at various locations along the expandable portion 200 and/or the insertion catheter 101. A radiopaque ink bead may be placed at a distal end of the expandable portion for alignment of the apparatus during fluoroscopy. The one or more radiopaque bands and radiopaque ink bead, using radiopaque materials such as barium sulfate, tantalum, or other materials known to increase radiopacity, allows a medical professional to view the apparatus using fluoroscopy techniques. The one or more radiopaque bands also provide visibility during inflation of the expandable portion to determine the precise positioning of the expandable portion during placement and inflation. The one or more radiopaque bands permit visualization of any voids that may be created by air that gets entrapped in the expandable portion. The one or more radiopaque bands permit visualization to preclude the expandable portion from misengaging or not meeting a bone due to improper inflation to maintain a uniform expandable portion/bone interface.
In an embodiment, the expandable portion 200 can have a length greater than about 300 mm and a diameter greater than about 14 mm. In such embodiments, there is the potential that during the curing of the light-sensitive liquid, a far distal area 214 of the expandable portion 200 will exhibit a shrinkage upon cure of about 2 to about 3 percent, while a proximal area 212 of the expandable portion 200 is being cured. In an embodiment, to prevent this from transpiring, the inner lumen 220 of the expandable portion 200 can be pressurized by virtue of the infusion of either air or other fluids (saline, water) through port 125 at the proximal end 112 of the insertion catheter 101. The infusion will cause internal diameter pressure against the light-sensitive liquid contained within the inner cavity 235 of the expandable portion 200 so that during the curing process, the pressure keeps the light-sensitive liquid pressurized, and up in contact with inner surface 230 of the expandable portion 200. When the light-conducting fiber is inserted within the inner lumen 220 and the light-sensitive liquid is infused—the extra space is pressed down on the inner lumen 220. In an embodiment, an expandable portion of the present disclosure has a diameter ranging from about 4 mm to about 30 mm. In an embodiment, an expandable portion of the present disclosure has a length ranging from about 20 mm to about 300 mm. An expandable portion of the present disclosure may be round, flat, cylindrical, oval, rectangular or any desired shape for a given application. In an embodiment, an expandable portion of the present disclosure has a diameter of about 4 mm and a length of about 30 mm. In an embodiment, an expandable portion of the present disclosure has a diameter of about 5 mm and a length of about 40 mm. In an embodiment, an expandable portion of the present disclosure has a diameter of about 6 mm and a length of about 30 mm. In an embodiment, an expandable portion of the present disclosure has a diameter of about 6 mm and a length of about 40 mm. In an embodiment, an expandable portion of the present disclosure has a diameter of about 6 mm and a length of about 50 mm. In an embodiment, an expandable portion of the present disclosure has a diameter of about 7 mm and a length of about 30 mm. In an embodiment, an expandable portion of the present disclosure has a diameter of about 7 mm and a length of about 40 mm. In an embodiment, an expandable portion of the present disclosure has a diameter of about 7 mm and a length of about 50 mm.
In an embodiment, an outer surface of an expandable portion of the present disclosure is resilient. In an embodiment, an outer surface of an expandable portion of the present disclosure is substantially even and smooth. In an embodiment, an outer surface of an expandable portion of the present disclosure is not entirely smooth and may have some small bumps or convexity/concavity along the length. In an embodiment, an outer surface of an expandable portion of the present disclosure may have ribs, ridges, projections, bumps or other shapes. In an embodiment, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable portion improve penetration of the at least one fastener into the expandable portion. In an embodiment, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable portion improve penetration of the at least one fastener into the expandable portion anywhere along a length of the expandable portion. In an embodiment, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable portion increase friction between the outer surface of the expandable portion and the at least one fastener so as to reduce slippage of the at least one fastener as the at least one fastener is driven towards the outer surface of the expandable portion. In an embodiment, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable portion interacts with a threaded portion of the at least one fastener so as to improve penetration and fastening of the at least one fastener into the expandable portion. In an embodiment, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable portion interact with a tip of the at least one fastener to improve the wedge ability of the tip of the fastener so as to decrease the driving force needed to penetrate the expandable portion. In an embodiment, an outer surface of an expandable portion of the present disclosure has an uneven geometry. In an embodiment, an outer surface of an expandable portion of the present disclosure has a textured surface which provides one or more ridges that allow grabbing. In an embodiment, the one or more ridges on the textured surface of the expandable portion allow grabbing of the at least one fastener so as to improve the penetration of the at least one fastener into the expandable portion. In an embodiment, the one or more ridges on the textured surface of the expandable portion allow grabbing of bone so as to improve adhesion between the expandable portion and bone as regenerating bone grows onto the outer surface of the expandable portion. In an embodiment, abrasively treating an outer surface of an expandable portion of the present disclosure for example via chemical etching or air propelled abrasive media improves the connection and adhesion between the outer surface of the expandable portion and a bone. The surfacing may significantly increase the amount of surface area that comes in contact with the bone resulting in a stronger grip. In an embodiment, the textured surface promotes bone growth onto the expandable portion. In an embodiment, the textured surface promotes bone growth of regenerating bone onto the outer surface of the expandable portion by grabbing the regenerating bone as it grows. In an embodiment, an expandable portion of the present disclosure is made by extruding material into a tube shape, and then forming the tube into a balloon. When forming the tube into the balloon, the balloon can be, for example, pre-stamped or milled to include a desired design, desired shape or surface modification. Then, the tube is heated and radially expanded via compressed air for a specific amount of time. The formed balloon is cooled and includes the desired design, desired shape or surface modification.
In an embodiment, an expandable portion of the present disclosure has an outer surface that is coated with materials such as drugs, bone glue, proteins, growth factors, or other coatings. For example, after a minimally invasive surgical procedure an infection may develop in a patient, requiring the patient to undergo antibiotic treatment. An antibiotic drug may be added to an outer surface of an expandable portion of the present disclosure to prevent or combat a possible infection. Proteins, such as, for example, bone morphogenic protein or other growth factors have been shown to induce the formation of cartilage and bone. In an embodiment, a growth factor is added to an outer surface of an expandable portion of the present disclosure to help induce the formation of new bone. In an embodiment, as the formation of new bone is induced the new bone interacts with a textured outer surface of the expandable portion so that new bone is formed onto the textured outer surface of the expandable portion. Due to the lack of thermal egress of light-sensitive liquid in an expandable portion of the present disclosure, the effectiveness and stability of the coating is maintained.
In an embodiment, a stiffness of any of the expandable portion of the present disclosure can be increased due to the presence of external stiffening members or internal stiffening members. In an embodiment, a wrapping, sheathing or an attachment of Nitonol or other metallic memory-type metal piece(s) are aligned in a longitudinal fashion, with multiple rods being placed circumferentially around the expandable portion so as to have these metallic pieces change their configuration under a temperature change. In an embodiment, an inner surface of the metallic pieces (those surfaces that are in contact with the external circumferential surface of the intramedullary implant) are polished to increase internal reflection of the light from the light-conducting fiber. The metallic pieces are designed to be load-bearing shapes. In an embodiment, the metallic pieces have a low profile and can handle large loads. In an embodiment, metallic pieces may be positioned on the external circumferential surface of an expandable portion. The metallic pieces can be aligned in a longitudinal fashion, circumferentially around the expandable portion and can be interconnected with one another via connecting means such as wires. The wires will help hold the longitudinal metallic pieces in position. In an embodiment, the metallic pieces expand to increase the strength of the hardened expandable portion. In an embodiment, the metallic pieces contract to increase the strength of the hardened expandable portion. In an embodiment, metallic pieces are positioned on an internal circumferential surface of an expandable portion. In an embodiment, two metallic memory-type metal wires, such as nitonol, are positioned within an expandable portion. Heat from a light-conducting fiber makes the metal wires get smaller, tensioning the hardened expandable portion. In an embodiment, heat from a light-conducting fiber and reaction with the polymerization process, makes the metal wires get smaller, tensioning the hardened expandable portion. In an embodiment, an expandable portion is wrapped with a plurality of flat metallic plates that move into a corrugated or other shape upon a temperature change to increase the strength of the previously flat metal plate into a shape capable of handling a load. In an embodiment, the metals are rectangular, semicircular, hexagonal, or triangular in section, although not all embodiments are limited to these shapes.
An expandable portion typically does not have any valves. One benefit of having no valves is that the expandable portion may be inflated or deflated as much as necessary to assist in the fracture reduction and placement. Another benefit of the expandable portion having no valves is the efficacy and safety of the implant. Since there is no communication passage of light-sensitive liquid to the body there cannot be any leakage of liquid because all the liquid is contained within the expandable portion. In an embodiment, a permanent seal is created between the expandable portion that is both hardened and affixed prior to the insertion catheter 101 being removed. The expandable portion may have valves, as all of the embodiments are not intended to be limited in this manner.
In an embodiment, an expandable portion of the present disclosure includes a pathway sufficiently designed for passing a cooling medium. Once the expandable portion is expanded, a cooling media may be delivered within (via an internal lumen) or around (via external tubing) the expandable portion in order to prevent the possibility of overheating. Medium used for cooling includes, but is not limited to, gases, liquids and combinations thereof. Examples of gases include, but are not limited to, inert gases and air. Examples of liquids include, but are not limited to, water, saline, saline-ice mixtures, liquid cryogen. In an embodiment, the cooling media is water. The cooling media can be delivered to the expandable portion at room temperature or at a cooled temperature. In an embodiment, the cooling media improves the numerical aperture between that of the light-conducting fiber and the inner lumen for the light-conducting fiber because any air existing between the light-conducting fiber and the material of the expandable portion is taken away so as to improve light transmission. Therefore, the light transmission will be light-conducting fiber-cooling media-expandable portion-light-sensitive liquid as opposed to light-conducting fiber-air-expandable portion-light-sensitive liquid. In an embodiment, the cooling media transmitted through the inner lumen of the expandable portion takes away extraneous heat. In an embodiment, no cooling media is used.
In an embodiment, the inner lumen of the expandable portion penetrates through a distal end of the expandable portion for cooling through the length of the expandable portion. In an embodiment, the inner lumen has a return flow path for cooling. In an embodiment, the inner lumen is pressurized to move the cooling media in the inner lumen. In an embodiment, the expandable portion has external helical tubing for providing cooling media to the expandable portion.
In an embodiment, a light-conducting fiber can be introduced into the inner lumen of the expandable portion and activated to cure the light-sensitive liquid, while a cooling medium may flow through the inner lumen and out the distal end of the expandable portion.
In the embodiment shown in
In the embodiment shown in
Fasteners can be inserted anywhere along the length of an expandable portion of the present disclosure as there are no predrilled holes that determine where the fasteners must be inserted. The fasteners can also be inserted through an expandable portion from any direction and from any angle, independently of each other. This variable placement of fasteners from multiple directions and from multiple angles may help secure an expandable portion in place, reduce rotational ability of the implant, and increase the torsional and axial strength of the implant. In an embodiment, adding 3 mm fasteners to an 8×80 mm intramedullary implant may increase the torsional strength from approximately 8.5 inches per pound to approximately 21.2 inches per pound. It is importance to note that the torsional strength may be a function of bone strength, bone size, bone geometry, fastener size, fastener quality and other characteristics. The fasteners can also be inserted through an expandable portion to any desired depths, independently of each other. For example, although in the embodiments shown in
In an embodiment, a fastener may be inserted at approximately a ninety degree angle to an expandable portion. In an embodiment, a fastener may be inserted at an angle of less than approximately ninety degrees to an expandable portion. In an embodiment, a fastener may be inserted at an angle of more than approximately ninety degrees to an expandable portion. Fasteners can also be inserted from multiple directions and from multiple angles. In an embodiment, fasteners may be inserted from approximately opposite sides allowing them to be approximately parallel to one another. In an embodiment, fasteners may be inserted from approximately ninety degree angles to one another allowing them to be approximately perpendicular to one another. In an embodiment, fasteners may be inserted from less or more than approximately ninety degree angles to one another. The fasteners can also be inserted to any desired depth. In an embodiment, the fasteners can be inserted in such a manner that the distal ends extend beyond an outer surface of the expandable portion. In an embodiment, the distal end of the fasteners extending beyond an outer surface of the expandable portion can be received by a bone plate. In an embodiment, the fasteners can be inserted in such a manner that the distal ends remain within a lumen of an expandable portion. In an embodiment, the fasteners can be inserted in such a manner that a portion of the proximal end of the fastener penetrates the bone plate and the distal end remains within a lumen of the expandable portion. The proximity of the fasteners from one another can also vary depending on the specific application. Increasing the proximity of the fasteners to one another may help secure the expandable portion in place and reduce rotational ability of the intramedullary implant.
By inserting the fastener anywhere along the length of an expandable portion, at any angle and to any desired depth, an intramedullary implant of the present disclosure may increase a user's control over determining optimal fastener placement and reducing or eliminating the need for aiming systems to guide the fastener into place. Accordingly, the user is able to determine the optimal placement of fasteners based on each patient's specific situation rather than on the predrilled holes. For instance, certain situations may require having more fasteners placed in closer proximity while other situations may require fewer fasteners spaced further apart. By increasing user control of fastener placement, an intramedullary implant of the present disclosure may also reduce the likelihood of harming soft tissue, nerves, ligaments or muscles during placement. In conventional intramedullary implants, there may be a risk of injury to tissue, radial or ulna nerves, ligaments or muscles associated with inserting fasteners into predetermined spaces. Predetermined spaces require specific fastener location and orientation and may not accommodate a large variation in patient anatomies. As a result, injuries, including pain and loss of function, to surrounding tissue, nerves, ligaments and/or muscles may occur.
In an embodiment, a method for stabilizing a fractured bone includes penetrating the fractured bone to gain access to a medullary cavity of the fractured bone, inserting an expandable portion into the medullary cavity of the fractured bone, introducing a light-sensitive liquid into the expandable portion through at least one lumen of an insertion catheter connected to the expandable portion, separating the insertion catheter from the expandable portion at a predetermined site, and stabilizing the fractured bone by placing one or more fasteners through the fractured bone and into the expandable portion, wherein the fastener is placed into the expandable portion at any location along the length of the expandable portion, and at any angle and to any penetration depth relative to the expandable portion. In an embodiment, the ability to deliver the at least one fastener anywhere along the length of the expandable portion reduces the time of the procedure, compared to a similar procedure using conventional fixation devices. In an embodiment, the ability to deliver the at least one fastener anywhere along the length of the expandable portion reduces the requirement/need for additional incremental radiation exposure to the patient and the doctor.
The access hole 1010 extends through a hard compact outer layer 1020 of the bone into the relatively porous inner or cancellous tissue 1025. For bones with marrow, the medullary material should be cleared from the medullary cavity prior to insertion of the inventive device. Marrow is found mainly in the flat bones such as hip bone, breast bone, skull, ribs, vertebrae and shoulder blades, and in the cancellous material at the proximal ends of the long bones like the femur and humerus. Once the medullary cavity is reached, the medullary material including air, blood, fluids, fat, marrow, tissue and bone debris should be removed to form a void. The void is defined as a hollowed out space, wherein a first position defines the most distal edge of the void with relation to the penetration point on the bone, and a second position defines the most proximal edge of the void with relation to the penetration site on the bone. The bone may be hollowed out sufficiently to have the medullary material of the medullary cavity up to the cortical bone removed. There are many methods for removing the medullary material that are known in the art and within the spirit and scope on the presently disclosed embodiments. Methods include those described in U.S. Pat. No. 4,294,251 entitled “Method of Suction Lavage,” U.S. Pat. No. 5,554,111 entitled “Bone Cleaning and Drying system,” U.S. Pat. No. 5,707,374 entitled “Apparatus for Preparing the Medullary Cavity,” U.S. Pat. No. 6,478,751 entitled “Bone Marrow Aspiration Needle,” and U.S. Pat. No. 6,358,252 entitled “Apparatus for Extracting Bone Marrow.”
A guidewire (not shown) may be introduced into the bone 1002 via the access hole 1010 and placed between bone fragments 1004 and 1006 of the bone 1002 to cross the location of a fracture 1005. The guidewire may be delivered into the lumen of the bone 1002 and crosses the location of the break 1005 so that the guidewire spans multiple sections of bone fragments. As shown in
Once orientation of the bone fragments 1004 and 1006 are confirmed to be in a desired position, the light-sensitive liquid may be hardened within the expandable portion 200, as shown in
As shown in
In an embodiment, a bone plate is used in conjunction with an intramedullary implant of the present disclosure. The bone plate may have any number of openings and can have a variety of shapes, sizes, and thicknesses for use in a variety of applications. The bone plate may have smooth openings, as well as, threaded openings. The smooth openings are generally used to receive a non-locking fastener and the threaded openings are generally used to receive a locking fastener. In an embodiment, the openings comprise pre-drilled holes. Non locking fasteners are generally used to draw the bone transversely toward the plate or to move the bone laterally through the use of compression plates. The bone plate may be positioned under soft tissue and on the exterior of the long bone and helps bridge the fractured portion of the long bone. In an embodiment, the bone plate is sufficiently strong to support a normal load on the long bone as the bone heals. In an embodiment, the bone plate has a stiffness substantially similar to a stiffness of the long bone. In an embodiment, the bone plate is made from a material that is non-toxic, non-antigenic and non-immunogenic. In an embodiment, the bone plate can be provided with a stiffness so that as the long bone heals, the bone plate allows the long bone to carry a larger load. In an embodiment, providing a bone plate that allows the long bone to carry a larger load as the bone heals avoids a reduction of bone mass of the bone. In an embodiment, the bone plate acts as a backing plate into which fasteners may be driven. In an embodiment, the when the distal end of the fasteners penetrate the outer surface of the expandable portion and are received by the bone plate, the bone plate helps hold the intramedullary implant in place.
The bone plate can be made from any material sufficiently strong to support the load placed on the bone while the bone heals. Examples of suitable materials include, but are not limited to titanium, stainless steel, ceramic polymeric materials such as hydroxyapatite, bioresorbable polymers, such as polylactic acid (PLA) or polycaprolactone (PCL), or other similar materials that allow the bone to be held together so that the bone can regenerate the tissue and regain most of the bone's original strength.
In an embodiment, an intramedullary implant includes a non-compliant expandable portion having an outer surface and an inner cavity, wherein a hardened light-sensitive liquid is contained within the inner cavity of the expandable portion; and at least one fastener penetrating the expandable portion at a first location along the outer surface of the expandable portion and into the inner cavity of the expandable portion, wherein the at least one fastener penetrates the expandable portion at a user selected location anywhere along a length of the expandable portion, and wherein the at least one fastener penetrates the expandable portion at any angle relative to the expandable portion.
In an embodiment, a method for stabilizing a fractured bone includes penetrating the fractured bone to gain access to a medullary cavity of the fractured bone; inserting an expandable portion into the medullary cavity of the fractured bone; introducing a light-sensitive liquid monomer into the expandable portion so as to expand the expandable portion, wherein the light-sensitive liquid monomer is introduced into the expandable portion through at least one lumen of an insertion catheter releasably connected to the expandable portion, hardening the light-sensitive liquid monomer within the expandable portion so as to polymerize the light-sensitive liquid monomer; separating the insertion catheter from the expandable portion; and stabilizing the fractured bone, wherein the at least one fastener extends through an outer surface of the fractured bone, through an inner surface of the fractured bone, and into the expandable portion at any location along a length of the expandable portion, at any angle and to any penetration depth relative to the expandable portion.
In an embodiment, a method for realigning bone fragments includes providing an apparatus, wherein the apparatus includes a releasable expandable portion mounted on an insertion catheter, the insertion catheter having an inner void for passing a light-sensitive liquid, and an inner lumen for accepting a light-conducting fiber; positioning the expandable portion within a medullary canal of the bone fragments, wherein the expandable portion extends across/spans the bone fragments (fragment line); infusing the light-sensitive liquid into the inner void of the insertion catheter so that the light-sensitive liquid is delivered to the expandable portion and expands the expandable portion to a desired volume so as to realign the bone fragments; halting the infusing of the light-sensitive liquid; inserting a light-conducting fiber into the inner lumen of the insertion catheter so that the light-conducting fiber resides in the expandable portion; activating the light-conducting fiber to begin a polymerization process to polymerize the light-sensitive liquid within the expandable portion; removing the light-conducting fiber from the insertion catheter; releasing the expandable portion from the insertion catheter; selecting a location along a length of the expandable portion for insertion of at least one screw, wherein the selected location can be at any point along the length of the expandable portion; drilling a hole at the selected location through the bone fragment and the expandable portion; and inserting the at least one screw through the hole within the expandable portion, wherein the expandable portion having the at least one screw stabilizes the bone fracture.
In an embodiment, a method for bone fracture stabilization includes providing an apparatus for placement of an expandable portion within an intramedullary space spanning at least two fractured bone segments of a bone, wherein the apparatus includes a releasable expandable portion mounted on an insertion catheter, the insertion catheter having an inner void for passing a light-sensitive liquid; and an inner lumen for accepting a light-conducting fiber; inserting the expandable portion into the fractured bone to span the fractured bone segments; infusing the light-sensitive liquid into the inner void of the insertion catheter so that the light-sensitive liquid is delivered to the expandable portion; halting the infusing of the light-sensitive liquid; inserting the light-conducting fiber into the inner lumen of the insertion catheter so that the light-conducting fiber resides in the expandable portion; activating the light-conducting fiber to begin a polymerization process to polymerize the light-sensitive liquid within the expandable portion; removing the light-delivery fiber from the insertion catheter; releasing the expandable portion from the insertion catheter; selecting a location along the length of the expandable portion for insertion of at least one fastener, wherein the selected location can be at any point along the length of the expandable portion; drilling a hole at the selected location through the bone and the expandable portion; and inserting the at least one fastener through the hole within the expandable portion, wherein the expandable portion and the at least one fastener stabilizes the bone fracture. In an embodiment, the method is performed during a closed intramedullary nailing surgery.
All patents, patent applications, and published references cited herein are hereby incorporated by reference in their entirety. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or application. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art.
This application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/259,699, filed Nov. 10, 2009, which is hereby incorporated herein by reference in its entirety for the teachings therein.
| Number | Date | Country | |
|---|---|---|---|
| 61259699 | Nov 2009 | US |
