Patent Application
20140276846
All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. For example, this application incorporates by reference in their entireties U.S. Patent Publication No. 2011/0087294 and U.S. Patent Publication No. 2011/0118785.
This application relates generally to broaches. More specifically, this application relates to broaches used to cut bone.
Many types of hardware are available both for the fixation of bones that are fractured and for the fixation of bones that are to be fused (arthrodesed).
For example, the human hip girdle is made up of three large bones joined by three relatively immobile joints. One of the bones is called the sacrum and it lies at the bottom of the lumbar spine, where it connects with the L5 vertebra. The other two bones are commonly called “hip bones” and are technically referred to as the right ilium and-the left ilium. The sacrum connects with both hip bones at the sacroiliac joint (in shorthand, the SI-Joint).
The SI-Joint functions in the transmission of forces from the spine to the lower extremities, and vice-versa. The SI-Joint has been described as a pain generator for up to 22% of lower back pain.
To relieve pain generated from the SI Joint, sacroiliac joint fusion is typically indicated as surgical treatment, e.g., for degenerative sacroiliitis, inflammatory sacroiliitis, iatrogenic instability of the sacroiliac joint, osteitis condensans ilii, or traumatic fracture dislocation of the pelvis. Currently, screws and screws with plates are used for sacro-iliac fusion. At the same time the cartilage has to be removed from the “synovial joint” portion of the SI joint. This requires a large incision to approach the damaged, subluxed, dislocated, fractured, or degenerative joint.
An alternative implant that is not based on the screw design can also be used to fuse the SI-Joint. Such an implant can have a triangular cross-section, for example, as further described below. To insert the implant, a cavity can be formed into the bone, and the implant can then be inserted into the cavity using a tool such as an impactor.
To improve integration of the implant with the bone, bone graft material can be applied to the implant before insertion into the bore or during the implantation procedure. Therefore, it would be desirable to provide systems, devices and methods for incorporating bone graft materials with the implant at the implantation site.
In addition, some methods of implantation of the implant require one or more drilling steps to form the bone cavity for receiving the implant. To reduce the number of drilling steps and simplify the procedure, it would be desirable to provide a modified broach that can efficiently cut the bone cavity with less drilling.
This application relates generally to broaches. More specifically, this application relates to broaches used to shape bores in bone. The broaches can shape the bores to receive an implant and also cut additional tubes or channels for receiving bone graft material and/or biologic aids.
In general, in one embodiment, a broach for shaping a bore in bone to receive an implant includes an elongate body with a proximal end, a distal end, at least three faces between the distal end and the proximal end, a plurality of apices formed at the junctions between adjacent faces, and a longitudinal axis. A lumen extends throughout the elongate body about the longitudinal axis, and the lumen is sized and shaped for receiving a guide pin. A plurality of cutting surfaces are located on the distal end of the elongate body for shaping the bore to receive the implant, and the plurality of cutting surfaces are oriented along the plurality of apices and become progressively smaller in size towards the distal end. A plurality of additional cutting surfaces is aligned with the plurality of apices for cutting channels in the bore to receive a bone graft material.
This and other embodiments can include one or more of the following features. Each face of the elongate body can include a channel extending along at least a portion of the longitudinal length of the elongate body. The elongate body can include three faces that define a substantially triangular cross-sectional profile transverse to the longitudinal axis. The plurality of cutting surfaces can be angled towards the distal end of the elongate body. The plurality of additional cutting surfaces can be partially circular. The plurality of additional cutting surfaces can be partially rectilinear.
In general, in one embodiment, a method for inserting an implant in bone includes: (1) drilling a bore into the bone; (2) inserting a broach to shape the bore to receive the implant and to form channels for receiving a bone graft material; (3) inserting the implant into the shaped bore; and (4) filling the channels with a bone graft material.
This and other embodiments can include one or more of the following features. The shaped bore can be rectilinear with a plurality of apices, and the channels can be formed at the apices of the shaped bore. The shaped bore can be triangular. The method can include inserting a guide pin into the bone. The steps of drilling a bore, inserting a broach, and inserting the implant all can be performed over the guide pin.
In general, in one embodiment, a broach for shaping a bore in bone to receive an implant includes an elongate body with a proximal end, a distal end, at least three faces between the distal end and the proximal end, a plurality of apices formed at the junctions between adjacent faces, and a longitudinal axis. A lumen extends throughout the elongate body about the longitudinal axis, and the lumen is sized and shaped for receiving a guide pin. A plurality of cutting surfaces is located on the distal end of the elongate body for shaping the bore to receive the implant. The plurality of cutting surfaces are oriented along the plurality of apices and become progressively smaller in size towards the distal end. A tapered distal tip portion at the distal end of the elongate body tapers to a distal opening of the lumen.
This and other embodiments can include one or more of the following features. The tapered distal tip portion can form a cutting surface around the opening of the lumen. The tapered distal tip portion can include a plurality of beveled faces that are angled towards the distal end. The tapered distal tip portion can include a smooth tapering surface that reaches the distal opening of the lumen. The elongate body can include three faces that define a substantially triangular cross-sectional profile transverse to the longitudinal axis. The plurality of cutting surfaces can be angled towards the distal end of the elongate body. Each face of the elongate body can include a channel extending along at least a portion of the longitudinal length of the elongate body.
In general, in one embodiment, a method for inserting an implant in bone includes: (1) inserting a guide pin into the bone; (2) inserting a sharp tipped broach over the guide pin to create a cavity for receiving the implant, wherein the cavity can be formed without first drilling a bore into the bone over the guide pin; and (3) inserting the implant into the cavity.
This and other embodiments can include one or more of the following features. The step of inserting a sharp tipped broach over the guide pin to create a cavity can include cutting the bone adjacent to the guide pine with one or more cutting edges at a distal end of the sharp tipped broach, and driving the sharp tipped broach further into the bone until a plurality of cutting surfaces on the sharp tipped broach can cut into and remove the bone surrounding the guide pin to form the cavity.
The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
Elongated, stem-like implant structures 20 like that shown in
In one embodiment of a lateral approach (see
Before undertaking a lateral implantation procedure, the physician identifies the SI-Joint segments that are to be fixated or fused (arthrodesed) using, e.g., the Fortin finger test, thigh thrust, FABER, Gaenslen's, compression, distraction, and diagnostic SI joint injection.
Aided by lateral, inlet, and outlet C-arm views, and with the patient lying in a prone position, the physician aligns the greater sciatic notches and then the alae (using lateral visualization) to provide a true lateral position. A 3 cm incision is made starting aligned with the posterior cortex of the sacral canal, followed by blunt tissue separation to the ilium. From the lateral view, the guide pin 38 (with sleeve (not shown)) (e.g., a Steinmann Pin) is started resting on the ilium at a position inferior to the sacrum end plate and just anterior to the sacral canal. In the outlet view, the guide pin 38 should be parallel to the sacrum end plate at a shallow angle anterior (e.g., 15.degree. to 20.degree. off the floor, as
Over the guide pin 38 (and through the soft tissue protector), the pilot bore 42 is drilled in the manner previously described, as is diagrammatically shown in
The shaped broach 44 is tapped into the pilot bore 42 over the guide pin 38 (and through the soft tissue protector) to create a broached bore 48 with the desired profile for the implant structure 20, which, in the illustrated embodiment, is triangular. This generally corresponds to the sequence shown diagrammatically in
In some embodiments, a dilator can be used to open a channel though the tissue prior to sliding the soft tissue protector assembly 210 over the guide pin. The dilator(s) can be placed over the guide pin, using for example a plurality of sequentially larger dilators or using an expandable dilator. After the channel has been formed through the tissue, the dilator(s) can be removed and the soft tissue protector assembly can be slid over the guide pin. In some embodiments, the expandable dilator can serve as a soft tissue protector after being expanded. For example, after expansion the drill sleeve and guide pin sleeve can be inserted into the expandable dilator.
As shown in
The implant structures 20 are sized according to the local anatomy. For the SI-Joint, representative implant structures 20 can range in size, depending upon the local anatomy, from about 35 mm to about 60 mm in length, and about a 7 mm inscribed diameter (i.e. a triangle having a height of about 10.5 mm and a base of about 12 mm). The morphology of the local structures can be generally understood by medical professionals using textbooks of human skeletal anatomy along with their knowledge of the site and its disease or injury. The physician is also able to ascertain the dimensions of the implant structure 20 based upon prior analysis of the morphology of the targeted bone using, for example, plain film x-ray, fluoroscopic x-ray, or MRI or CT scanning.
Using a lateral approach, one or more implant structures 20 can be individually inserted in a minimally invasive fashion across the SI-Joint, as has been described. Conventional tissue access tools, obturators, cannulas, and/or drills can be used for this purpose. Alternatively, the novel tissue access tools described above and in co-pending U.S. application Ser. No. 61/609,043, titled “TISSUE DILATOR AND PROTECTER” and filed Mar. 9, 2012, which is hereby incorporated by reference in its entirety, can also be used. No joint preparation, removal of cartilage, or scraping are required before formation of the insertion path or insertion of the implant structures 20, so a minimally invasive insertion path sized approximately at or about the maximum outer diameter of the implant structures 20 can be formed.
The implant structures 20 can obviate the need for autologous bone graft material, additional pedicle screws and/or rods, hollow modular anchorage screws, cannulated compression screws, threaded cages within the joint, or fracture fixation screws. Still, in the physician's discretion, bone graft material and other fixation instrumentation can be used in combination with the implant structures 20.
In a representative procedure, one to six, or perhaps up to eight, implant structures 20 can be used, depending on the size of the patient and the size of the implant structures 20. After installation, the patient would be advised to prevent or reduce loading of the SI-Joint while fusion occurs. This could be about a six to twelve week period or more, depending on the health of the patient and his or her adherence to post-op protocol.
The implant structures 20 make possible surgical techniques that are less invasive than traditional open surgery with no extensive soft tissue stripping. The lateral approach to the SI-Joint provides a straightforward surgical approach that complements the minimally invasive surgical techniques. The profile and design of the implant structures 20 minimize or reduce rotation and micromotion. Rigid implant structures 20 made from titanium provide immediate post-op SI Joint stability. A bony in-growth region 24 comprising a porous plasma spray coating with irregular surface supports stable bone fixation/fusion. The implant structures 20 and surgical approaches make possible the placement of larger fusion surface areas designed to maximize post-surgical weight bearing capacity and provide a biomechanically rigorous implant designed specifically to stabilize the heavily loaded SI-Joint.
To improve the stability and weight bearing capacity of the implant, the implant can be inserted across three or more cortical walls. For example, after insertion the implant can traverse two cortical walls of the ilium and at least one cortical wall of the sacrum. The cortical bone is much denser and stronger than cancellous bone and can better withstand the large stresses found in the SI-Joint. By crossing three or more cortical walls, the implant can spread the load across more load bearing structures, thereby reducing the amount of load borne by each structure. In addition, movement of the implant within the bone after implantation is reduced by providing structural support in three locations around the implant versus two locations.
In some embodiments, it may be desirable to add a bone graft material and/or biologic aid along with the implant in order to promote bone growth around and/or into the implant. An embodiment of a modified broach 800 is illustrated in
The modified broach 800 can have a cross-sectional profile that generally matches the shape of the implant. For example, for a triangular shaped implant, the modified broach 800 can have a generally triangular shaped cross-sectional profile. Likewise, for an implant with a rectangular, square, or any other rectilinear shape, the modified broach 800 can have a generally matching cross-sectional profile. In some embodiments, as illustrated in
In some embodiments as illustrated in
The additional cutting surfaces 810 can cut tubes or channels from the shaped bore that can be filled bone graft material and/or a biologic aid. In some embodiments, the drilled bore can be enlarged using the modified broach 800 to shape the bore into a general shape that matches the implant while also cutting out bone graft channels that extend beyond the general implant profile. In some embodiments, the bone graft channels can be located at the apexes of the shaped bore.
In some embodiments, a standard broach can be used to shape the bore while additional tubes or channels can be made separately with a drill and specialized drill bit or drill fixture. In some embodiments, a standard broach can be used to initially shape the bore while a second broach can be used to cut out the additional tubes or channels.
As described above, the implant can be inserted into the shaped bore while bone graft material and/or a biologic aid can be inserted into the additional cut tubes or channels. In some embodiments, the bone graft material and/or biologic aids can be formed into solid rods, with shapes matching the cut tubes or channels, which can be impacted into each cut tube or channel. In other embodiments, the bone graft material and/or biologic aids can be injected with a specialized syringe or other injection device into each of the cut tubes or channels. In some embodiments, the bone graft material and/or biologic aids can also be smeared or coated onto the implant either before or as the implant in inserted into the shaped bore.
The bone graft materials can be a liquid, gel, slurry, paste, powder, solid structure, matrix of granular material or other form, and can include a biologic aid that can promote and/or enhance bony ingrowth, tissue repair, and/or reduce inflammation, infection and pain. For example, the bone graft materials and/or biologic aid can include growth factors, such as bone morphogenetic proteins (BMPs), hydroxyapatite in, for example, a liquid or slurry carrier, demineralized bone, morselized autograft or allograft bone, bone fragments, medications to reduce inflammation, infection or pain such as analgesics, antibiotics and steroids. In addition, a blood pellet formed by centrifugation of the patient's blood, for example, can be included in the bone graft materials. In some embodiments, the blood pellet can be added in pellet form to the bone graft materials, while in other embodiments, the blood pellet can be disassociated and mixed or incorporated with other bone graft materials and/or biologic aids. In some embodiments, the growth factors can be human recombinant growth factors, such as hr-BMP-2 and/or hr-BMP-7, or any other human recombinant form of BMP, for example. The carrier for the biologic aid can be a liquid or gel such as saline or a collagen gel, for example. The biologic aid can also be encapsulated or incorporated in a controlled released formulation so that the biologic aid is released to the patient at the implant site over a longer duration. For example, the controlled release formulation can be configured to release the biologic aid over the course of days or weeks or months, and can be configured to release the biologic aid over the estimated time it would take for the implant site to heal. The amount of biologic aid delivered to the implant structure can be controlled using a variety of techniques, such as controlling or varying the amount of coating material applied to the implant and/or controlling or varying the amount of biologic aid incorporated into the coating material. In some embodiments, in may be important to control the amount of biologic aid delivered because excessive use of certain biologic aids can result in negative effects such as radicular pain, for example.
In some embodiments, the filling of the cutting tubes or channels with bone graft material at the apices around the implant helps reduce haloing artifacts around the implant. As shown in
However, in contrast to the embodiment of the broach illustrated in
However, as discussed briefly above, in contrast to the embodiment of the broach illustrated in
The pyramid shaped tip 1204 can comprise three faces 1206 that taper towards the distal end of the broach 1200. At the distal end of the broach 1200 can be an opening to the lumen 1202. Surround the opening can be a plurality of cutting surfaces 1208, 1209 located at both the apices between the faces 1206 and along the distal end of each face 1206 between the apices. The cutting surfaces 1208, 1209 are configured to cut and chisel out the bone around the guide pin to form the bore for the implant. Furthermore, the cutting surfaces 1208 located at the apices can be arranged to form teeth with a pointed tip that can penetrate into and cut and chisel the bone surrounding the guide pin.
Variations and modifications of the devices and methods disclosed herein will be readily apparent to persons skilled in the art. As such, it should be understood that the foregoing detailed description and the accompanying illustrations, are made for purposes of clarity and understanding, and are not intended to limit the scope of the invention, which is defined by the claims appended hereto. Any feature described in any one embodiment described herein can be combined with any other feature of any of the other embodiment whether preferred or not.
It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference for all purposes.
This application claims priority to U.S. Patent Provisional Application No. 61/793,357, filed Mar. 15, 2013, and titled “SYSTEMS AND METHODS FOR IMPLANTING BONE GRAFT AND IMPLANT,” which is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61793357 | Mar 2013 | US |
