BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which:
FIGS. 1 and 2 are schematic illustrations of a vertebral body implant in a compressed state thereof, in accordance with an embodiment of the present invention;
FIGS. 3 and 4 are schematic illustrations of the implant of FIGS. 1 and 2, in an expanded state thereof, in accordance with an embodiment of the present invention;
FIG. 5 is a schematic illustration of an exemplary expansion tool coupled to the implant of FIGS. 1-4, in accordance with an embodiment of the present invention;
FIGS. 6A and 6B are schematic anatomical drawings showing suitable implantation approaches for treating vertebral compression fractures, in accordance with various embodiments of the present invention;
FIG. 6C is a schematic anatomical drawing showing a suitable implantation approach for treating an upper tibial compression fracture, in accordance with an embodiment of the present invention;
FIGS. 7-12 are schematic illustrations showing an implantation procedure, in accordance with an embodiment of the present invention;
FIGS. 13A, 13b, 13C and 13D are schematic illustrations of the implant of FIGS. 1-4, in accordance with respective embodiments of the present invention; and
FIGS. 14A, 14B, and 14C are schematic illustrations of implantation apparatus, in accordance with respective embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the accompanying drawings wherein like reference numerals refer to the same or similar elements, FIGS. 1 and 2 are schematic illustrations of a vertebral body implant 20 in a compressed state thereof, in accordance with an embodiment of the present invention, FIG. 2 being a cross-sectional view of the implant shown in FIG. 1. A distance r1 between an outer edge 2 and a longitudinal axis 3 of the implant is typically between about 2 mm and about 5 mm, for example about 2.5 mm. Prior to being rolled into the shape shown in FIG. 1, the dimensions of the implant are typically between about 0.1 mm and about 0.5 mm thick (e.g., about 0.2 mm), between about 10 mm and 30 mm wide (e.g., about 20 mm), and between about 50 mm and about 150 mm long (e.g., about 90 mm).
In general, the size of implant 20 is selected based on the patient's physiology. The implant 20 typically comprises a strong, flexible, biocompatible material. In one embodiment, the implant 20 comprises a chrome-based stainless steel, such as 316 stainless steel, cobalt chrome, or a titanium-based alloy (e.g., nitinol). Other materials, such as those described in the references incorporated by reference herein, are also suitable.
Referring now to FIGS. 3, 4 and 5, FIGS. 3 and 4 are schematic illustrations of the implant 20 of FIGS. 1 and 2, in an expanded state thereof, in accordance with an embodiment of the present invention, and FIG. 5 is a schematic illustration of an expansion tool 7 coupled to implant 20, in accordance with an embodiment of the present invention. The implant 20 is adapted to be placed within a vertebral body using known techniques. For example, the techniques may include (a) techniques similar to those employed in a kyphoplasty procedure in order to place a balloon within a vertebral body, (b) techniques described in one or more of the references described above, and/or (c) techniques utilizing approaches used for taking a vertebral biopsy (such as described in Campbell's Operative Orthopaedics, Ninth edition, Volume one, Part VI, Chapter 17, incorporated by reference herein).
During use, expansion tool 7 is coupled to an inner edge 1, or inner edge region, of the implant 20 (in a manner described below) and, once at the implantation site, is rotated by a physician in order to unwind and expand the implant 20. This increases the implant's outer radius from r1 (FIG. 2) to r2 (FIG. 4) by about 5 mm to about 15 mm (e.g., about 7.5 mm). FIGS. 1-4 are not necessarily drawn to scale.
As appropriate, techniques described herein may be practiced using techniques and apparatus described in one or more of the references cited above in the Background section of the application.
FIGS. 6A and 6B are schematic anatomical drawings showing suitable implantation approaches, in accordance with various embodiments of the present invention. Placement of implant 20 inside a vertebral body 22 is typically performed using one of three approaches: a lateral approach A1, a parapedicular approach A2, or a transpedicular approach A3. Using one or more drills of appropriate diameters, a hole is typically drilled in the outer portion of the vertebral body 22 in order to facilitate one of the these approaches. As appropriate, techniques cited hereinabove by Campbell for taking a biopsy, and/or in U.S. Patent Application Publication No. 2005/0038517, PCT Patent Publication Nos. WO 04/086934, WO 03/039328 and/or WO 04/034924 may be adapted for use in these embodiments.
FIG. 6C is a schematic anatomical drawing showing a suitable implantation approach for treating an upper tibial compression fracture, in accordance with an embodiment of the present invention. Placement of implant 20 inside a tibia 24 is typically performed using a lateral approach A4. It is to be understood that some embodiments of the present invention are described with respect to vertebral fractures by way of illustration and not limitation. The scope of the present invention includes application of these techniques in the treatment of other fractures, such as tibial fractures, as well, the implementation of which would be readily apparent to those skilled in the art.
Reference is now made to FIGS. 7-12, which are schematic illustrations showing an implantation procedure, in accordance with an embodiment of the present invention. FIG. 7 shows a vertebral body 22 that has sustained a compression fracture. FIG. 8 shows the fractured vertebral body with implant 20 placed therein, still in the compressed state. FIG. 9 shows expansion tool 7 beginning to expand the implant inside the vertebral body (in this case, using approach A1 described above with reference to FIG. 6A). FIG. 10 shows implant 20 fully expanded inside vertebral body 22, after tool 7 has been withdrawn. FIG. 11 shows another perspective view of fully-expanded implant 20 inside the vertebral body, and a hole 5 in a portion of the vertebral body, through which the implant 20 was inserted. FIG. 12 shows vertebral body 22 after surgery, with its height generally restored by implant 20. (Implant 20 is not visible in FIG. 12.) Optionally, hole 5 is filled following the implantation and expansion of implant 20.
Referring now to FIGS. 13A, 13B, 13C and 13D, which are schematic illustrations of implant 20 in accordance with respective embodiments of the present invention, FIG. 13A shows implant 20 comprising a coupling member 30 on inner edge 1 thereof, or inner edge region, for coupling the implant 20 to expansion tool 7 (for example, enabling the tool 7 shown in FIG. 14B to removably grip coupling member 30 and enable rotation of the implant 20 upon rotation of expansion tool 7). Coupling member 30 may be a flat piece of material attached or otherwise adhered to the inner edge region of the implant 20.
Alternatively, a coupling member is provided which is shaped such that the expansion tool 7 couples thereto by means of any other available form of a coupling mechanism including but not limited to male-female type fittings known in the art (see FIG. 13C wherein a coupling portion 34 of coupling member 32 has a female fitting and a complementary male fitting or polygonal tip 8 is mounted onto a threaded expansion tool 7 or bolt) and threads (see FIG. 13D).
FIG. 13B shows a coupling member 32 of implant 20, which typically extends across the width of implant 20, but alternatively may extend across only a portion of the width of the implant 20, and comprises an elongate member, rod or shaft and a female coupling portion 34 by means of which expansion tool 7 sets the final, expanded state or size of implant 20. In the embodiment shown in FIG. 13B, an outer edge 2 of implant 20 is jagged, e.g., shaped to define teeth, and/or is shaped or otherwise treated (e.g., heat treated) to improve adhesion to vertebral body 22. Instead of teeth, other forms and constructions of the outer edge region of the implant 20 may be used to provide enhanced adhesion of the implant 20 to the bone.
As appropriate, coupling member 30, 32 or 34 extends partially across the width of implant 20, or completely across the width of implant 20.
For some applications, the outer 5 mm to 10 mm of implant 20 (i.e., the 5 mm to 10 mm closest to outer edge 2) is configured to enhance adhesion to vertebral body 22. With this enhanced adhesion, the physician is able to place implant 20 in the compressed state in the vertebral body and to firmly secure the implant 20 thereto. Once the outer edge 2 of the implant is firmly in place, rotation of expansion tool 7 is directly translated into a desired level of expansion of the implant 20. When teeth or other protruding members are used to provide the adhesion, they are typically less than 10 mm long, and/or otherwise configured, such that they do not penetrate the upper cortex bone of the vertebral body and/or damage the disc or other tissue outside of the vertebral body.
FIGS. 14A, 14B and 14C are schematic illustrations of distal tips of expansion tool 7, in accordance with respective embodiments of the present invention. The expansion tool 7 shown in FIG. 14A comprises a threaded tip 40, which engages a threaded portion of a coupling member such as coupling member 34 shown in FIG. 13D, or coupling member 34 shown in FIGS. 13B and 13C when engaged with polygonal tip 8 (shown in FIG. 13C). Coupling member 32 may be shaped to define a threaded portion within the longitudinal body thereof and/or within coupling portion 34.
FIG. 14B shows a grasping tip 42, which either grasps inner edge 1 of implant 20 directly, or grasps a portion of a coupling member 30 of the implant 20 (shown in FIG. 13A).
FIG. 14C shows a polygonal male tip 44 formed or otherwise arranged in connection with the expansion tool 7, which couples with a suitably shaped portion 34 of a coupling member 32 on implant 20 (e.g., as shown in FIGS. 13B and 13C). For some applications, the bore shown in tip 44 allows passage therethrough of threaded tip 40 (see FIG. 13C). A person of ordinary skill in the art having read the disclosure of the present patent application will realize that other coupling techniques are also suitable.
For some applications, a method is provided for treating a bone with a compression fracture. The method includes inserting a device in a compressed state into a first site of the bone. The device may comprise, as appropriate, a coil as described above, or other suitable components, such as a balloon, a spring, or forceps that can apply force directed outwardly. The device is expanded under physician control while the device is in the bone, to reduce a first location of the fracture. The device is thereafter compressed while at the first site, and moved within the bone to a second site, either without removing the device from the bone at all or removing the device from the bone and inserting it into the bone through a different access hole leading to the second site. The device is expanded under physician control while at the second site, to reduce a second location of the fracture. The device is typically moved to a plurality of locations within the bone in order to reduce the fracture at each of these locations, according to the nature of the fracture. In an embodiment, the device is maintained within the bone following the procedure, i.e., it remains implanted within the bone.
It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.
Patent Application
20080009868
