# Patent

## Title
Distal tip for bone fixation devices

## Abstract

Distal tip designs for bone fixation devices are disclosed. In some embodiments, a system for bone fixation includes a delivery catheter having a proximal end and a distal end; an expandable member having a proximal region and a distal region, wherein the expandable member is releasably attached about the distal end of the delivery catheter at the proximal region of the expandable member; a distal cap attached to the distal region of the expandable member to seal the expandable member; a light conducting fiber; and a light-sensitive liquid; wherein the delivery catheter has an inner void for passage of a light-sensitive liquid into the expandable member to expand the expandable member and an inner lumen for passage of the light conducting fiber into the expandable member to cure the light-sensitive liquid inside the expandable member.

## Background
RELATED APPLICATIONS
This application claims the benefit of and priority to U.S. Provisional Application No. 61/739,972, which was filed on Dec. 20, 2012, and which is incorporated herein by reference in its entirety.


FIELD
The embodiments disclosed herein relate to distal tip for systems for use during an bone fixation procedure and methods of their use.
BACKGROUND
Fracture repair is the process of rejoining and realigning the ends of broken bones. Currently there are several internal approaches to repair, strengthen and support a fractured bone. Conventional internal fixation devices include wires, plates, rods, pins, nails, and screws to support the fractured bone directly, as well as the addition of reinforcing materials to the fractured bone. Newer internal fixation devices include expandable members that can be expanded with curable material and hardened inside the intramedullary cavity of a bone to provide a conformal fit inside the intramedullary cavity, which leads to greater support and strength to the healing bone. However, there is still a need for further improvements of such internal fixation devices.
SUMMARY
Distal tip designs for bone fixation devices are disclosed. According to some aspects illustrated herein, there is provided a device for bone fixation that includes a delivery catheter comprising an outer tube and an inner tube disposed within the outer tube and extending beyond the outer tube; an expandable member having a proximal region and a distal region, the expandable member being releasably attached about a distal end of the delivery catheter at the proximal region of the expandable member, and a distal cap attached to the distal region of the expandable member to seal the expandable member; and an inner compartment in the distal region of the expandable member, the inner tube and enable movement of the inner tube within the inner compartment.
According to some aspects illustrated herein, there is provided a system for bone fixation that includes a delivery catheter having a proximal end and a distal end; an expandable member having a proximal region and a distal region, wherein the expandable member is releasably attached about the distal end of the delivery catheter at the proximal region of the expandable member; a distal cap attached to the distal region of the expandable member to seal the expandable member; a light conducting fiber; and a light-sensitive liquid; wherein the delivery catheter has an inner void for passage of a light-sensitive liquid into the expandable member to expand the expandable member and an inner lumen for passage of the light conducting fiber into the expandable member to cure the light-sensitive liquid inside the expandable member.
According to some aspects illustrated herein, there is provided a method for bone fixation that includes advancing to a fractured bone a device comprising a delivery catheter having a proximal end and a distal end; an expandable member having a proximal region and a distal region, wherein the expandable member is attached about the distal end of the delivery catheter at the proximal region of the expandable member; and a distal cap attached to the distal region of the expandable member to seal the expandable member; positioning the expandable member within an intramedullary cavity of the fractured bone; expanding the expandable member with a light-sensitive liquid; and curing the light-sensitive liquid within the expandable member.



BRIEF DESCRIPTION OF THE DRAWINGS
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.
FIG. 1 is a prospective view of an embodiment of a device for repairing a weakened or fractured bone of the present disclosure.
FIG. 2 is a close-up view of an embodiment of a distal end of a device for repairing a weakened or fractured bone of the present disclosure.
FIG. 3 illustrates an embodiment of a distal tip design for a device for repairing a weakened or fractured bone of the present disclosure.
FIG. 4 illustrates an embodiment of a distal tip design for a device for repairing a weakened or fractured bone of the present disclosure.
FIG. 5 illustrates an embodiment of a distal tip design for a device for repairing a weakened or fractured bone of the present disclosure.
FIG. 6 illustrates an embodiment of a distal tip design for a device for repairing a weakened or fractured bone of the present disclosure.
FIG. 7A illustrates an embodiment of a distal tip design for a device for repairing a weakened or fractured bone of the present disclosure.
FIG. 7B illustrates an embodiment of a distal tip design for a device for repairing a weakened or fractured bone of the present disclosure.
FIG. 8 shows a close up view of an embodiment of a proximal end of a device for repairing a weakened or fractured bone of the present disclosure.
FIG. 9A, FIG. 9B, FIG. 9C, FIG. 9D and FIG. 9E illustrate an embodiment method for repairing a weakened or fractured bone of the present disclosure.



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.
DETAILED DESCRIPTION
Systems and methods for bone fixation procedures are disclosed herein. In some embodiments, distal tip designs for internal bone fixation devices are disclosed.
FIG. 1 illustrates the main components of an embodiment of a device for repairing a weakened or fractured bone. The device 100 includes a delivery catheter 101 having an elongated shaft with a proximal end 112, a distal end 114, and a longitudinal axis therebetween. In an embodiment, the delivery catheter 101 has a diameter of about 3 mm. The distal end 104 of the delivery catheter 101 terminates in an expandable member 200 (also referred to herein as a conformable member or a balloon portion). The expandable member 200 may move from a deflated state to an inflated state when at least one reinforcing material is delivered to the expandable member 200. In some embodiments, the expandable member 200 may be releasably attached to the delivery catheter 101. In some embodiments, the expandable member 200 may be placed inside an intramedullary cavity of a bone for internal bone fixation.
FIG. 2 is a side view of an embodiment of a distal end 114 of the flexible delivery catheter 101. The distal end 114 includes the expandable member 200 releasably mounted on the flexible delivery catheter 101. The expandable member 200 has a wall 202 with an outer surface 205 and an inner surface 230. The inner surface 230 defines an inner cavity 235. In some embodiments, the delivery catheter 101 may include multiple inner lumens or voids. For example, as shown in FIG. 2, the delivery catheter 101 may include an outer tube 209 and a central tube 220 concentrically disposed within the delivery catheter 101. An inner void 210 may be formed between the outer tube 209 and the central tube 220. The inner void 210 may be utilized for passing a light-sensitive liquid into the inner cavity 235 of the expandable member 200. In some embodiments, the central tube 220 includes an inner lumen 211 for passing a light-conducting fiber (which is not illustrated in FIG. 2) into the expandable member 200 to cure the light sensitive liquid inside the inner cavity 235 of the expandable member, as described in detail below. It should be noted that while the delivery catheter 101 is described as having the central lumen 220 concentric with the outer tube 209, the central lumen 220 may be off-set relative to the outer tube 209.
In some embodiments, the expandable member 200 is manufactured from a thin-walled, non-compliant (non-stretch/non-expansion) conformable material. The expandable member 200 may be formed of a pliable, resilient, conformable, and strong material, including but not limited to urethane, polyethylene terephthalate (PET), nylon elastomer and other similar polymers. In some embodiments, the expandable member 200 of the present disclosure is constructed out of a PET nylon aramid or other non-consumable materials. The expandable member 200 may be impregnated with a radiopaque material to enhance the visibility of the expandable member 200. The expandable member 200 is biocompatible, thus preventing or reducing possible adverse reactions after insertion into a fractured bone. In some embodiments, the expandable member 200 is made from a material that is non-toxic, non-antigenic and non-immunogenic.
The expandable member 200 includes a proximal area 212 and a distal area 214. The proximal area 212 of the expandable member 200 is releasably connected to the delivery catheter 101. The distal area 214 may be connected to the delivery catheter 101 in a variety of ways.
In reference to FIG. 3, in some embodiments, the distal area 214 of the expandable member 200 may be connected to a distal cap 300, which may be disposed at the distal end of the central tube 220. The distal cap 300 terminates and seals off the area 214 of the expandable member 200 to prevent the flow of a light-sensitive liquid outside the balloon and the ingress of bodily fluids inside the balloon. One potential benefit of utilizing the distal cap 300 is ease of manufacture and more consistent tip quality when compared to traditional melt forming of expandable member 200 directly to the delivery catheter. An additional benefit of the use of the distal cap 300 may also include the ability to reflect back or scatter light radiating from the end of the conducting fiber to improve the light-sensitive liquid cure times or depth of cure. The reflected light from the distal cap 300 may increase the energy that is directed towards the light-sensitive liquid in the expandable member 200 and thus may increase the photo-initiation rate (and thus polymerization rate) of the light-sensitive liquid.
In some embodiments, the distal cap 300 may be formed, molded or machined from an implant grade polymer (e.g., PET), or another biocompatible material. The distal cap 300 may also be made from a filled material. For example, the PET polymer may be blended with a radiopaque material (e.g., barium sulfate, tungsten, tantalum, etc.) such that the distal cap 300 may be viewed with the assistance of fluoroscopic imaging. In some embodiments, the distal cap 300 may also be covered with a reflective material such as a gold film (or other metallic highly polished implant grade film) to enable the distal cap 300 to reflect light radiating from the end of the light pipe back into the balloon. This reflected light can help to reduce the cure time of the light sensitive liquid contained within the expandable member 200 to due to the increase in light energy directed at the light sensitive liquid. In some embodiments, the distal cap 300 may also be fabricated from a crystalline material (such as crystalline PET) to block the transmission of light through the end of the device 100 and to reflect and/or scatter the light back to the light sensitive liquid in the expandable member 200.
As illustrated in FIG. 3, a distal cap 300 includes a body 302 having a proximal end 304 and a distal end 306. The body 302 defines an inner compartment 303 for receiving the central tube 220 therein. In some embodiments, the inner compartment 303 is tubular to accommodate the central tube 220 therein. The proximal end 304 of the body 302 is open to allow the central tube 220 to be inserted into the inner compartment 303. The distal cap 300 may stabilize the central tube 220 and may minimize snaking or bowing of the central tube 220 during the operation. In some embodiments, the central tube 300 may be free floating within the distal cap 300, that is, the distal end of the central tube 220 is capable of movement within the inner compartment 303. In some embodiments, being free floating within the inner compartment 303, the central tube 220 can move within the inner compartment 303 in a radial direction, a longitudinal direction or both a radial direction and a longitudinal direction. Because in some embodiments the central tube 220 is free-floating, unrestrained or unbound within the inner compartment 303, the central tube 220 can automatically adjust to the pressure maintained within the expandable member 200 to minimize or even eliminate the deformation of the central tube along its length. For example, as the expandable member 200 expands and contracts in diameter and length during infusion or withdrawal of the light sensitive liquid, the central tube 220 can adjust in length thereby reducing the stress on the central tube 220 and the light conducting fiber inside the central tube 220. In some embodiments, where the central tube 220 is free floating within the distal cap 300, the pleating and wrapping of the expandable member 200 may be improved, which may prevent damage to the expandable member 200 during manufacturing (improved yields), decrease the likelihood of leak occurrence either during manufacturing or in use, and potentially result in improvement on profile (able to wrap down to a smaller diameter) and insertion force (due to reduced friction).
While the central tube 220 may be free floating, in some embodiments, the central tube 220 may also be tethered to the distal cap by means of a filament or fiber to prevent the central tube 220 from becoming completely dislodged from within the distal cap 300. The filament or fiber may be elastic or rigid under tension and compression. In some embodiments, the central tube 220 may be rigidly secured to the distal cap 300. The central tube 220 may be secured inside the compartment 303 by press fitting the central tube 220 into the compartment 303; applying permanent adhesive on the surfaces between the central tube 220 and the compartment 303; melt bonding the two surfaces together or other techniques.
The distal end 306 of the body 302 may be either open or closed. In some embodiments, the distal cap 300 closes the distal tip 306 of the body 302 to close the distal tip 306. The distal cap 300 includes an inner surface 309, which faces the body 302, and an outer surface 310, which faces away from the body 302. In some embodiments, the outer surface 310 of the distal cap 300 may be rounded or smooth to provide the device 100 with an atraumatic distal point. In some embodiments, the distal cap 300 may have a semi-circular shape with a flat inner surface and a curved outer surface. In some embodiments, the body 302 may be open as long as there is a seal created, such as by for example, sealing the central tube 220 to the inner surface of the inner compartment 303 to prevent movement of fluids in and out of the expandable member 200.
In reference to FIG. 3, in some embodiments, the material forming the expandable member 200 may be attached to the outer surface of the body 302. In some embodiments, the outer surface of the body 302 includes recessed attachment sections 312a, 312b to which the material of the expandable member 200 can be attached. In some embodiments, the outer surface of the body 302 may be recessed by a depth approximately equal to the thickness of the expandable member material. In this manner, when the expandable member material is attached to the body 302, the outside of the expandable member material is substantially aligned with the outer surface 310 of the distal cap 300. The material of the expandable member 200 can be attached to the body 302 by a variety of methods, including, without limitation, adhesives such as cyano-acrylates or epoxies, crimping metallic rings over the expandable portion, melt bonding the expandable member to the body 302 with the use of heat (e.g., RF generated), ultrasonically welding the expandable member to the body 302, or another method or combination of methods.
In reference to FIG. 4, in some embodiments, the material of the expandable member 200 may be attached to the inner surface of the body 302 of the distal cap 300.
In reference to FIG. 5, in some embodiments, the body 302 may have a slotted wall, formed by a first wall or prong 314 and a second wall or prong 316 spaced apart from one another to form a slot 318 between the first wall 314 and the second wall 316. The material of the expandable member 200 can be inserted into the slot 318 and secured within the slot 318 between the first wall 314 and the second wall 316 by a variety of methods. This design may provide additional separation resistance between the two components which may translate to an increase in burst pressure and fatigue resistance at this interface.
In some embodiments, the central tube 220 may be sealed distally by a melt 221 formed by a process such as an RF heated mold (as shown in FIG. 3, FIG. 4 and FIG. 5). Alternatively, as shown in FIG. 6, the central tube 220 may be sealed with a tube plug 320 before being inserted into the distal cap 300. The tube plug 320 can be fabricated in a similar fashion to the distal cap 300 in terms of material and fillers (providing the same benefits described previously for the distal cap 300). Alternatively, the tip of the central tube 220 can be left not sealed, as long as there is a seal between the outer surface of the central tube 220 and the inner surface of the compartment 303 to prevent leaks into or out of the central tube 220.
In reference to FIG. 7A, in some embodiments, the body 302 of the distal cap 300 is formed by the walls of the expandable member 200. In reference to FIG. 7B, in some embodiments, the distal cap 300 may be melt formed from the distal end material of the expandable member 200, while the walls of the expandable member 200 may form the body 302 of the distal cap 300, defining the inner compartment 303. In some embodiments, the end cap may be formed from a separate heat shrink tube. The heat shrink tube may be placed inside the expandable member or external to the expandable member to permit melt forming and/or sealing of the end of the expandable member. In the embodiments shown in FIG. 7A and FIG. 7B, the central tube 220 may be either free floating or may be attached to the distal cap 300.
In reference to FIG. 8, a close-up view of an embodiment proximal end 112 of the delivery catheter 101 is illustrated. The proximal end 112 of the flexible delivery catheter 101 includes at least two ports. In the embodiment shown in FIG. 1, the proximal end 112 includes three ports 115, 125, and 135. Port 115 can accept, for example, a light-conducting fiber. In some embodiments, the light-conducting fiber is an optical fiber. In some embodiments, the optical fiber has an outer diameter from about 1 mm to about 3 mm. The optical fiber is sized to pass through an inner lumen of the delivery catheter 101. The optical fiber can be made from any material, such as glass, silicon, silica glass, quartz, sapphire, plastic, combinations of materials, or any other material, and may have any diameter. In some embodiments, the optical fiber is made from a polymethyl methacrylate (PMMA) core with a transparent polymer cladding, often a fluoropolymer such as polytetrafluoroethylene. It should be appreciated that the above-described characteristics and properties of the optical fibers are exemplary and not all embodiments of the present disclosure are intended to be limited in these respects. Port 125 can accept, for example, a syringe housing air or fluid. In some embodiments, port 125 can be used as an air vent during sterilization. Port 135 can accept, for example, a syringe housing a light-sensitive liquid. In some embodiments, the light-sensitive liquid is a liquid monomer. In some embodiments, the syringe maintains a low pressure during the infusion and aspiration of the light-sensitive liquid. In some embodiments, the syringe maintains a low pressure of about 10 atmospheres or less during the infusion and aspiration of the light-sensitive liquid. In some embodiments, the syringe maintains a pressure of between about 1 and about 3 atmospheres.
Light-sensitive liquid can be introduced into the proximal end 112 of the delivery catheter 101 and passes through the inner void 210 of the delivery catheter 101 up into the inner cavity 235 of the expandable member 200 to move the expandable member from a deflated state to an inflated state when the light-sensitive liquid is delivered to the expandable member, in order to form a rigid orthopedic stabilizer. In some embodiments, 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 member of the present disclosure may be defined as enough light-sensitive liquid to expand the expandable member so that the expanded expandable member 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 some embodiments, a unit dose of a light-sensitive liquid of the present disclosure is contained within a container. In some embodiments, a unit dose of a light-sensitive liquid of the present disclosure is contained in an ampoule. In some embodiments, the expandable member is sufficiently shaped to fit within a space or a gap in a fractured bone. In some embodiments, 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 member. 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 delivery catheter 101 through port 115 and passes within an inner lumen of the delivery catheter 101 up into the expandable member. In some embodiments, the light source emits frequency that corresponds to a band in the vicinity of 390 nm to 770 nm, the visible spectrum. In some embodiments, the light source emits frequency that corresponds to a band in the vicinity of 410 nm to 500 nm. In some embodiments, 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 some embodiments, the liquid monomer is exposed to an appropriate frequency of light and intensity to cure the monomer inside the expandable member and form a rigid structure. In some embodiments, 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 some embodiments, 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 10 minutes) polymerize the monomer. This cure affixes the expandable member 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 delivery 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 some embodiments, the viscosity of the light-sensitive liquid has a viscosity of about 1000 cP or less. In some embodiments, the light-sensitive liquid has a viscosity ranging from about 650 cP to about 450 cP. The expandable member 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 some embodiments, a contrast material may be added to the light-sensitive liquid without significantly increasing the viscosity. Contrast materials include, but are not limited to, bismouth subcarbonate, barium sulfate, bismuth subcarbonate, tantalum, or other contrast materials known in the art. The light-sensitive liquid can be introduced into the proximal end of the delivery catheter and passes within the inner void of the delivery catheter up into an inner cavity of the expandable member to change a thickness of the expandable member without changing a width or depth of the expandable member. In some embodiments, 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 member 200 and/or the delivery catheter 101. A radiopaque ink bead may be placed at a distal end of the expandable member for alignment of the apparatus during fluoroscopy. The one or more radiopaque bands and radiopaque ink bead, using radiopaque materials such as bismouth subcarbonate, 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 member to determine the precise positioning of the expandable member during placement and inflation.
In some embodiments, the expandable member 200 can have a length greater than about 300 mm and a diameter greater than about 20 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 member 200 will exhibit a shrinkage upon cure of about 2 to about 3 percent, while a proximal area 212 of the expandable member 200 is being cured. In some embodiments, to prevent this from transpiring, the central tube 220 of the expandable member 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 delivery catheter 101. The infusion will cause internal diameter pressure against the light-sensitive liquid contained within the inner cavity 235 of the expandable member 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 member 200. When the light-conducting fiber is inserted within the central tube 220 and the light-sensitive liquid is infused, the extra space is pressed down on the central tube 220. In some embodiments, the central tube 220 is rigid and heat resistant so it does not deform, collapse or expand, due to the light energy from the light conducting fiber to facilitate easy removal of the light conducting fiber after the cure cycle. In some embodiments, an expandable member of the present disclosure has a diameter ranging from about 4 mm to about 30 mm. In some embodiments, an expandable member of the present disclosure has a length ranging from about 20 mm to about 500 mm. An expandable member of the present disclosure may be round, flat, cylindrical, oval, rectangular or any desired shape for a given application. In some embodiments, an expandable member of the present disclosure has a diameter of about 4 mm and a length of about 30 mm. In some embodiments, an expandable member of the present disclosure has a diameter of about 5 mm and a length of about 40 mm. In some embodiments, an expandable member of the present disclosure has a diameter of about 6 mm and a length of about 30 mm. In some embodiments, an expandable member of the present disclosure has a diameter of about 6 mm and a length of about 40 mm. In some embodiments, an expandable member of the present disclosure has a diameter of about 6 mm and a length of about 50 mm. In some embodiments, an expandable member of the present disclosure has a diameter of about 7 mm and a length of about 30 mm. In some embodiments, an expandable member of the present disclosure has a diameter of about 7 mm and a length of about 40 mm. In some embodiments, an expandable member of the present disclosure has a diameter of about 4 mm to about 20 mm and a length of about 30 mm to about 280 mm.
In some embodiments, an outer surface of an expandable member of the present disclosure is resilient. In some embodiments, an outer surface of an expandable member of the present disclosure is substantially even and smooth. In some embodiments, an outer surface of an expandable member of the present disclosure is not entirely smooth and may have some small bumps or convexity/concavity along the length. In some embodiments, an outer surface of an expandable member of the present disclosure may have ribs, ridges, projections, bumps or other shapes. In some embodiments, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable member improve penetration of the at least one fastener into the expandable member. In some embodiments, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable member improve penetration of the at least one fastener into the expandable member anywhere along a length of the expandable member. In some embodiments, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable member increase friction between the outer surface of the expandable member 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 member. In some embodiments, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable member 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 member. In some embodiments, the ribs, ridges, projections, bumps, or other shapes on the rough or uneven outer surface of the expandable member 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 member. In some embodiments, an outer surface of an expandable member of the present disclosure has an uneven geometry. In some embodiments, an outer surface of an expandable member of the present disclosure has a textured surface which provides one or more ridges that allow grabbing. In some embodiments, the one or more ridges on the textured surface of the expandable member allow grabbing of the at least one fastener so as to improve the penetration of the at least one fastener into the expandable member. In some embodiments, the one or more ridges on the textured surface of the expandable member allow grabbing of bone so as to improve adhesion between the expandable member and bone as regenerating bone grows onto the outer surface of the expandable member. In some embodiments, abrasively treating an outer surface of an expandable member 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 member 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 some embodiments, the textured surface promotes bone growth onto the expandable member. In some embodiments, the textured surface promotes bone growth of regenerating bone onto the outer surface of the expandable member by grabbing the regenerating bone as it grows. In some embodiments, an expandable member 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 some embodiments, an expandable member 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 member 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 some embodiments, a growth factor is added to an outer surface of an expandable member of the present disclosure to help induce the formation of new bone. In some embodiments, as the formation of new bone is induced the new bone interacts with a textured outer surface of the expandable member so that new bone is formed onto the textured outer surface of the expandable member. Due to the lack of thermal egress of light-sensitive liquid in an expandable member of the present disclosure, the effectiveness and stability of the coating is maintained.
In some embodiments, a stiffness of any of the expandable member of the present disclosure can be increased due to the presence of external stiffening members or internal stiffening members. In some embodiments, a wrapping, sheathing or an attachment of Nitinol or other metallic memory-type metal piece(s) are aligned in a longitudinal fashion, with multiple rods being placed circumferentially around the expandable member so as to have these metallic pieces change their configuration under a temperature change. In some embodiments, 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 some embodiments, the metallic pieces have a low profile and can handle large loads. In some embodiments, metallic pieces may be positioned on the external circumferential surface of an expandable member. The metallic pieces can be aligned in a longitudinal fashion, circumferentially around the expandable member 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 some embodiments, the metallic pieces expand to increase the strength of the hardened expandable member. In some embodiments, the metallic pieces contract to increase the strength of the hardened expandable member. In some embodiments, metallic pieces are positioned on an internal circumferential surface of an expandable member. In some embodiments, two metallic memory-type metal wires, such as Nitinol, are positioned within an expandable member. Heat from a light-conducting fiber makes the metal wires get smaller, tensioning the hardened expandable member. In some embodiments, heat from a light-conducting fiber and reaction with the polymerization process, makes the metal wires get smaller, tensioning the hardened expandable member. In some embodiments, an expandable member 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 some embodiments, the metals are rectangular, semicircular, hexagonal, or triangular in section, although not all embodiments are limited to these shapes.
An expandable member typically does not have any valves. One benefit of having no valves is that the expandable member may be inflated or deflated as much as necessary to assist in the fracture reduction and placement. Another benefit of the expandable member 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 member. In some embodiments, a permanent seal is created between the expandable member that is both hardened and affixed prior to the delivery catheter 101 being removed. The expandable member may have valves, as all of the embodiments are not intended to be limited in this manner.
In some embodiments, an expandable member of the present disclosure includes a pathway sufficiently designed for passing a cooling medium. Once the expandable member is expanded, a cooling media may be delivered within (via an internal lumen) or around (via external tubing) the expandable member 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 some embodiments, the cooling media is water. The cooling media can be delivered to the expandable member at room temperature or at a cooled temperature. In some embodiments, 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 member is taken away so as to improve light transmission. Therefore, light will be transmitted from the light-conducting fiber to the light-sensitive liquid through the cooling medium as opposed to through air. In some embodiments, the cooling media transmitted through the inner lumen of the expandable member takes away extraneous heat. In some embodiments, no cooling media is used.
In some embodiments, a light-conducting fiber can be introduced into the inner lumen of the expandable member 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 member.
In reference to FIG. 9A, FIG. 9B, FIG. 9C, FIG. 9D and FIG. 9E, embodiment methods for implanting an intramedullary implant of the present disclosure within the intramedullary space of a weakened or fractured bone are illustrated. A minimally invasive incision (not shown) may be made through the skin of the patient's body to expose a fractured bone 902. The incision may be made at the proximal end or the distal end of the fractured bone 902 to expose the bone surface. Once the bone 902 is exposed, it may be necessary to retract some muscles and tissues that may be in view of the bone 902. As shown in FIG. 9A, an access hole 910 may be formed in the bone by drilling or other methods known in the art. In some embodiments, the access hole 910 has a diameter of about 4 mm to about 7 mm. In some embodiments, the access hole 910 has a diameter of about 9 mm.
The access hole 910 extends through a hard compact (cortical) outer layer 920 of the bone into the relatively porous inner or cancellous tissue 925. 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 cleared or loosened 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. 5,707,974 entitled “Apparatus for Preparing the Medullary Cavity,” U.S. Pat. No. 6,478,751 entitled “Bone Marrow Aspiration Needle,” and U.S. Pat. No. 6,958,252 entitled “Apparatus for Extracting Bone Marrow.”
A guidewire (not shown) may be introduced into the bone 902 via the access hole 910 and placed between bone fragments 904 and 906 of the bone 902 to cross the location of a fracture 905. The guidewire may be delivered into the lumen of the bone 902 and may cross the location of the break 905 so that the guidewire spans multiple sections of bone fragments. As shown in FIG. 9B, the expandable member 200 of the delivery catheter 101 for repairing a fractured bone, which is constructed and arranged to accommodate the guidewire, is delivered over the guidewire to the site of the fracture 905 and spans the bone fragments 904 and 906 of the bone 902. Once the expandable member 200 is in place, the guidewire may be removed. The location of the expandable member 200 may be determined using at least one radiopaque marker 990 which is detectable from the outside or the inside of the bone 902. Once the expandable member 200 is in the correct position within the fractured bone 902, a delivery system which contains a light-sensitive liquid is attached to the port 195. The light-sensitive liquid is then infused through the inner void 210 in the delivery catheter 101 and enters the inner cavity 295 of the expandable member 200. This addition of the light-sensitive liquid within the expandable member 200 causes the expandable member 200 to expand, as shown in FIG. 9C. As the expandable member 200 is expanded, the fracture 905 is reduced. Unlike traditional implants, such as rods, that span the fracture site, the expandable member 200 of the present disclosure does more than provide longitudinal strength to both sides of the fractured bone. In some embodiments, the expandable member 200 having the design can be a spacer for reducing the fracture and for holding the fractured and compressed bones apart at the point of the collapsed fracture.
Once orientation of the bone fragments 904 and 906 are confirmed to be in a desired position, the light-sensitive liquid may be hardened within the expandable member 200, as shown in FIG. 9D, such as by illumination with a visible emitting light source. In some embodiments, during the curing step, a syringe housing a cooling media may be attached to the proximal end of the delivery catheter and continuously delivered to the expandable member 200. The cooling media can be collected by connecting tubing to the distal end of the inner lumen and collecting the cooling media via the second distal access hole. After the light-sensitive liquid has been hardened, the light source may be removed from the device. Alternatively, the light source may remain in the expandable member 200 to provide increased rigidity.
FIG. 9E shows an embodiment of a bone fixation device in a cavity of a bone after being separated from an introducer. For example, the expandable member 200 once hardened, may be released from the delivery catheter 101 to form a photodynamic bone fixation device inside the intramedullary cavity of the bone 902.
In some embodiments, a device for internal bone fixation includes an delivery catheter having a proximal end and a distal end, an expandable member having a proximal region and a distal region, wherein the expandable member is relesably attached about the distal end of the delivery catheter at its proximal region, and a distal cap attached to the distal region of the expandable member to seal the expandable member.
In some embodiments, a device for internal bone fixation includes an delivery catheter having a proximal end and a distal end, a distal cap positioned distally of the delivery catheter, an inner lumen extending through the delivery catheter past the distal end of the delivery catheter for insertion into the distal cap, and an expandable member releasably attached about the distal end of the delivery catheter at its proximal region and is sealed by the distal cap at its distal region.
In some embodiments, a system for internal bone fixation includes an delivery catheter having a proximal end and a distal end; an expandable member having a proximal region and a distal region, wherein the expandable member is relesably attached about the distal end of the delivery catheter at its proximal region, and a distal cap attached to the distal region of the expandable member to seal the expandable member; a light conducting fiber; and a light cure adhesive, wherein the delivery catheter has an inner void for passage of a light-sensitive liquid into the expandable member to expand the expandable member and an inner lumen for passage of a light conducting fiber into the expandable member to cure the light-sensitive liquid inside the expandable member.
In some embodiments, a method for internal bone fixation that includes advancing to a fractured bone a device that includes an delivery catheter having a proximal end and a distal end; an expandable member having a proximal region and a distal region, wherein the expandable member is relesably attached about the distal end of the delivery catheter at its proximal region, and a distal cap attached to the distal region of the expandable member to seal the expandable member; positioning the expandable member of the device within an intramedullary cavity of the fractured bone; expanding the expandable member with a light-sensitive liquid; and curing the light-sensitive liquid within the expandable member.
In some embodiments, a device for bone fixation includes a delivery catheter comprising an outer tube and an inner tube disposed within the outer tube and extending beyond the outer tube; an expandable member having a proximal region and a distal region, the expandable member being relesably attached about a distal end of the delivery catheter at the proximal region of the expandable member, and a distal cap attached to the distal region of the expandable member to seal the expandable member; and an inner compartment in the distal region of the expandable member, the inner compartment being configured to receive the inner tube and enable movement of the inner tube within the inner compartment.
In some embodiments, a system for bone fixation includes a delivery catheter having a proximal end and a distal end; an expandable member having a proximal region and a distal region, wherein the expandable member is releasably attached about the distal end of the delivery catheter at the proximal region of the expandable member; a distal cap attached to the distal region of the expandable member to seal the expandable member; a light conducting fiber; and a light-sensitive liquid; wherein the delivery catheter has an inner void for passage of a light-sensitive liquid into the expandable member to expand the expandable member and an inner lumen for passage of the light conducting fiber into the expandable member to cure the light-sensitive liquid inside the expandable member.
In some embodiments, a method for bone fixation includes advancing to a fractured bone a device comprising a delivery catheter having a proximal end and a distal end; an expandable member having a proximal region and a distal region, wherein the expandable member is attached about the distal end of the delivery catheter at the proximal region of the expandable member; and a distal cap attached to the distal region of the expandable member to seal the expandable member; positioning the expandable member within an intramedullary cavity of the fractured bone; expanding the expandable member with a light-sensitive liquid; and curing the light-sensitive liquid within the expandable member.
All patents, patent applications, and published references cited herein are hereby incorporated by reference in their entirety. It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. 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 applications. All such modifications and variations are intended to be included herein within the scope of this disclosure, and as fall within the scope of the appended claims

## Claims

1. A device for bone fixation comprising:
a delivery catheter comprising an outer tube and an inner tube, the inner tube disposed within the outer tube and the inner tube extending beyond the outer tube;
an expandable member having a proximal region and an open distal region, the expandable member being releasably attached about a distal end of the delivery catheter at the proximal region of the expandable member; and
a distal cap comprising an outer surface, an inner surface and a body extending from the inner surface, wherein an outer diameter of the body is smaller than a diameter of the inner surface to provide a recessed attachment section, the open distal region of the expandable member being attached to an outside of the body at the recessed attachment section, and wherein the distal cap terminates and seals off the open distal region of the expandable member to prevent the flow of a light-sensitive liquid from inside to outside of the expandable member and the ingress of bodily fluids inside the expandable member; and
an inner compartment defined by an inside of the body of the distal cap in the open distal region of the expandable member, wherein the inner compartment is sized so when the inner tube is inserted into the inner compartment, the inner tube is freely moveable within the inner compartment in a radial direction.

2. The device of claim 1 wherein the body of the distal cap is a tubular body defining the inner compartment for receiving and accommodating the inner tube, so as to stabilize and minimize bowing of the inner tube during operation.

3. The device of claim 2 wherein the delivery catheter includes:
an inner void between the inner tube and the outer tube and in fluid communication with an inner cavity within the expandable member to deliver the light-sensitive liquid into the inner cavity of the expandable member, and
an inner lumen extending along the inner tube for passing a light-conducting fiber into the expandable member to cure the light sensitive liquid inside the inner cavity of the expandable member.

4. The device of claim 3 further comprising a seal formed between the inner lumen and the inner compartment.

5. The device of claim 1 wherein the inner tube is freely moveable within the inner compartment in the radial direction and a longitudinal direction.

6. The device of claim 1 wherein the inner tube includes a plug insertable into the inner compartment of the distal cap.

7. The device of claim 1 wherein the distal cap includes a slotted wall into which the expandable member is inserted.

8. The device of claim 1 wherein an inner surface of the distal cap faces the body of the distal cap and is in communication with the light sensitive liquid inside a cavity of the expandable member, such that the distal cap seals off the open distal region of the expandable member.

9. The device of claim 1 wherein the distal cap is inserted into the open distal region of the expandable member.

10. A system for bone fixation comprising:
a delivery catheter having a proximal end and a distal end and an inner tube extending beyond an outer tube;
an expandable member having a proximal region and an open distal region, wherein the expandable member is releasably attached about the distal end of the delivery catheter at the proximal region of the expandable member;
a light-sensitive liquid;
a distal cap comprising an outer surface, an inner surface and a body extending from the inner surface, wherein an outer diameter of the body is smaller than a diameter of the inner surface to provide a recessed attachment section, the open distal region of the expandable member being attached to an outside of the body at the recessed attachment section, and wherein the distal cap terminates and seals off the open distal region of the expandable member to prevent the flow of a light-sensitive liquid from inside to outside of the expandable member and the ingress of bodily fluids inside the expandable member;
an inner compartment defined by an inside of the body of the distal cap in the open distal region of the expandable member, wherein the inner compartment is sized so when the inner tube is inserted into the inner compartment, the inner tube is freely moveable within the inner compartment in a radial direction; and
a light conducting fiber;
wherein the delivery catheter has an inner void for passage of the light-sensitive liquid into the expandable member to expand the expandable member and an inner lumen for passage of the light conducting fiber into the expandable member to cure the light-sensitive liquid inside the expandable member.

11. The system of claim 10 wherein the inner tube is free floating within the inner compartment of the distal cap.

12. The system of claim 10 wherein the inner tube includes a plug insertable into the inner compartment of the distal cap.

13. The system of claim 10 wherein the distal cap includes a slotted wall into which the expandable member is inserted.

14. A device for bone repair comprising:
a delivery catheter comprising an outer tube and a central tube, the central tube disposed within the outer tube and the central tube extending beyond the outer tube;
an expandable member having a proximal region and an open distal region, the proximal region of the expandable member being releasably engaged to a distal end of the delivery catheter; and
a distal cap
comprising an outer surface, an inner surface and a body extending from the inner surface, wherein an outer diameter of the body is smaller than a diameter of the inner surface to provide a recessed attachment section, the open distal region of the expandable member engaging an outside of the body at the recessed attachment section, and wherein the distal cap that terminates and seals off the open distal region of the expandable member to prevent the flow of a light-sensitive liquid from inside to outside of the expandable member and the ingress of bodily fluids inside the expandable member, wherein at least a portion of the distal cap includes a reflective material; and
an inner compartment defined by an inside of the body of the distal cap in the open distal region of the expandable member, wherein the inner compartment is sized so when the inner tube is inserted into the inner compartment, the inner tube is freely moveable within the inner compartment in a radial direction.

15. The device of claim 14 wherein the central tube is tethered to the distal cap by one of a filament or a fiber.

16. The device of claim 14 wherein the distal cap is in communication with the light sensitive liquid inside the expandable member.