The present disclosure, according to some embodiments, provides methods and implants that are useful for stabilizing or fusing a facet joint. In further embodiments, the present disclosure provides tools and kits that are useful carrying out the described methods.
In the posterior aspect of the lumbar spine, the anatomic structures that are responsible for motion are the facet joints. Facet joints are a set of synovial, plane joints between the articular processes of two adjacent vertebrae.
Currently, the standard of care for posterior stabilization of the lumbar spine is pedicle screw fixation. Pedicle screws are designed to prevent motion in the facet joints by anchoring into the bony pedicles that are located above and below the facet joint in question. The heads of the screws are then fastened to a rigid rod that connects the screws and thereby prevents motion of the facet joint. However, the placement of pedicle screws is disruptive to the surrounding muscles, carries the potential risk of nerve damage during their insertion, and can cause temporary and/or persistent post-operative pain due to their prominence. For example,
In some embodiments, the present disclosure provides a facet joint stabilization and fusion device that can avoid or overcome the problems discussed above. In one embodiment, there is an intra-facet stabilization implant that includes is a rigid device placeable into the facet joint. The rigid device is placeable to prevent motion via the exemplary mechanism of friction (e.g., between the device and the articulating surfaces of the facet joint). In one embodiment, the intra-facet stabilization devices include adequate surface area contact between the stabilization device and the nearly infinite variations in the anatomy of a facet joint. In one embodiment, the intra-facet stabilization devices are configured to accommodate fixation of facet joints in the spine that are oriented in a sagittal manner that would avoid unfavorable shear forces being placed upon the implant-facet joint interface.
In some embodiments, a facet joint stabilization and fusion device of the present disclosure incorporates a rigid implant that is sized and configured to be fully positioned within a facet joint such that no portion of the implant protrudes beyond the facet joint. In some embodiments, the rigid implant is configured to be utilized with a bone cement. The bone cement may include, for example, polymethyl methacrylate (PMMA) or other acrylic bone cements, calcium phosphate cements (CPCs), hydroxyapatite bone cements (HBCs), calcium sulfate cements (CSCs), and combinations thereof (e.g., calcium phosphate/hydroxyapatite or PMMA/calcium phosphate composite materials, etc.). In some embodiments, the bone cement may include any known bone cement that is useful for kyphoplasty or vertebroplasty. In some embodiments, the bone cement is PMMA or other material that mimics the properties of PMMA. The bone cement may be introduced in a fluid or flowable condition (e.g., injectable) and allowed to cure or harden after introduction into the facet joint. In some embodiments, the rigidity of the implant combined with the fluidity of the bone cement allows for an optimal surface of contact area with the facet joint. In some embodiments, this configuration will maximize the biomechanical strength of the facet joint stabilization. In addition, the ability to fill each aspect of the facet joint with bone cement, will maximize the amount of the construct that is under compressive load (the most tolerated form of force) as opposed to shear force.
In some embodiments, an implant for insertion into a facet joint includes a body that is sized to fit completely within the facet joint. In some embodiments, the body of the implant is constructed from a metal or metal alloy (e.g., titanium or titanium alloy). In some embodiments, the body includes a proximal end, a distal end opposite of the proximal end, the distal end having a tapered portion, and a first channel extending through the body from the proximal end to the distal end. In some embodiments, the body includes a second channel extending through the body from the proximal end to the distal end, the second channel being positioned between the first channel and a first lateral side of the body. In some embodiments, the body includes a third channel extending through the body from the proximal end to the distal end, the third channel being positioned between the first channel and a second lateral side of the body. In some embodiments, a width of the body between the first lateral side and the second lateral side is selected from a range of 5 mm to 8 mm, a length of the body between the proximal end and the distal end is selected from a range of 5 mm to 8 mm, and a height of the body at the proximal end is selected from a range of 2 mm to 4 mm.
In some embodiments, the body further includes a first tool engagement feature positioned on the first lateral side, and a second tool engagement feature positioned on the second lateral side. In some embodiments, the first tool engagement feature and the second tool engagement feature are discrete surface features on the first and second lateral sides. In some embodiments, the first tool engagement feature and the second tool engagement feature include one or more of an indent, recess, groove, slot, notch, protrusion, lip, flange, or the like sized and dimensioned to receive a portion of a tool.
In some embodiments, the body includes a top side having a first planar portion extending from the first lateral side to the second lateral side, and a bottom side opposite the top side and having a second planar portion extending from the first lateral side to the second lateral side. In some embodiments, the first planar portion of the top side and the second planar portion of the bottom side are substantially parallel to each other. In other embodiments, the first planar portion of the top side is acutely angled with respect to the second planar portion of the bottom side. In some such embodiments, the first planar portion of the top side is acutely angled with respect to the second planar portion of the bottom side by an angle selected from 7° to 15°.
In some embodiments, the first channel is disposed about a central axis of the body. In some embodiments, the body includes at least one plane of symmetry that intersects with the central axis. In some embodiments, the body includes two perpendicular planes of symmetry that intersect at the central axis. In some embodiments, the second and third channels are substantially parallel to the first channel. In some embodiments, the first channel, the second channel, and/or the third channel are unthreaded. In some embodiments, the body of the implant includes at least one opening on the first lateral side, the at least one opening on the first lateral side connecting to the second channel. In some embodiments, the body of the implant includes at least one opening on the second lateral side, the at least one opening on the second lateral side connecting to the third channel.
In some embodiments, a method for facet joint stabilization or fusion includes inserting any of the implants described herein into a facet joint of a patient. The facet joint may be a facet joint of the lumbar spine according to some embodiments. In some embodiments, the method further includes introducing a bone cement (e.g., PMMA, CPCs, HBCs, CSCs, etc.) into the facet joint. The bone cement is introduced into the facet joint in an uncured state. In some embodiments, the bone cement is introduced through the first channel of the body of the implant. In some embodiments, a portion of the bone cement exits the first channel and is allowed to at least partially fill a space of the facet joint surrounding the implant. In some embodiments, a portion of the bone cement that exits the first channel is allowed to flow into the second channel and/or the third channel of the body of the implant.
In some embodiments, a method according to the present disclosure includes coupling the implant to an inserter tool having a clamp configured to hold the implant in an insertion position relative to the facet joint. In some embodiments, the clamp comprises a pair of movable arms, and coupling the implant to the inserter tool includes causing the implant to engage the clamp between the pair of movable arms. In some embodiments, the inserter tool includes a hollow shaft that is axially aligned with the first channel when the implant is coupled to the inserter tool.
In some embodiments, the method further includes inserting an impactor tool into the hollow shaft of the inserter tool, the impactor tool having a tip portion that extends into the first channel of the implant when the impactor tool is fully inserted into the hollow shaft of the inserter tool. In some embodiments, the impactor tool is securable to the inserter tool with a threaded coupling. In some embodiments, the method includes removing the impactor tool from the hollow shaft of the inserter tool after inserting the implant into the facet joint of the patient. In some embodiments, after removing the impactor tool from the hollow shaft of the inserter tool, a cement introducer is inserted into the hollow shaft of the inserter tool. In some such embodiments, the cement introducer includes a hollow tip portion that extends into the first channel of the implant when the cement introducer is fully inserted into the hollow shaft of the inserter tool, and a fitting at an end opposite from the hollow tip portion, the fitting configured to couple to a bone cement source.
In some embodiments, the method includes coupling a bone cement source (e.g., syringe or other bone cement dispenser) to the fitting of the cement introducer, and causing bone cement to flow from the bone cement source through the cement introducer and into first channel of the implant. In some embodiments, the method includes causing bone cement to exit from the first channel of the implant to at least partially fills a space of the facet joint surrounding the implant. In some embodiments, the method further includes causing a portion of the bone cement to flow from the space of the facet joint into the second channel and/or third channel in the body of the implant.
The foregoing summary, as well as the following detailed description, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, there are shown in the drawings exemplary embodiments wherein like reference numerals indicate like elements throughout. It should be noted that aspects of the present disclosure can be embodied in different forms and thus should not be construed as being limited to the illustrated embodiments set forth herein. The elements illustrated in the accompanying drawings are not necessarily drawn to scale, but rather, may have been exaggerated to highlight particular features of the subject matter therein. Furthermore, the drawings may have been simplified by omitting elements that are not necessary for the understanding of the disclosed embodiments.
The present subject matter will now be described more fully hereinafter with reference to the accompanying Figures, in which representative embodiments are shown. The present subject matter can, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to describe and enable one of skill in the art.
A method for facet joint stabilization or fusion according to embodiments of the present disclosure includes positioning an implant within a facet joint and introducing a volume of bone cement (e.g., PMMA, CPCs, HBCs, CSCs, etc.) into the facet joint to at least partially surround the implant with the bone cement. In some embodiments, the implant is sized and configured to fit entirely within the facet joint. The facet joint, in some embodiments, may be a facet joint of the lumbar spine. In some embodiments, the bone cement is introduced into the facet joint through the implant itself. In some such embodiments, at least a portion of the volume of the bone cement is passed through a first channel in the implant and exits the implant to fill a space between the implant and a surface of the facet joint. In further embodiments, at least a portion of the bone cement, after exiting the first channel of the implant, is allowed to flow back into the implant through a second channel of the implant.
Methods according to embodiments of the present disclosure may be carried out during open spine surgery or through minimally invasive surgery, e.g., by utilizing a tubular retractor. In open spine surgery, the facet joint may be directly visualized and can be accessed directly by the surgeon. In embodiments using a tubular retractor, a surgeon may use intraoperative fluoroscopy or computerized navigation, for example, to place a tubular retractor over the facet joint that is to be fused or stabilized and be positioned in-line with the opening of the facet joint. Methods according to the present disclosure, may be performed bilaterally, assuming there is no facet joint cyst or compromise of the facet joint at the spinal level in question that would allow for cement extravasation into the spinal canal.
In some embodiments, once the facet joint is identified, electrocautery can be used to remove the dorsal aspect of the facet joint capsule that is overlying the facet joint to expose the opening of the facet joint. In some embodiments, tapered trial gauges of different predetermined dimensions (e.g., 1 mm, 2 mm, 3 mm, 4 mm) may be introduced into the facet joint in order to dilate the opening of the facet joint and to determine the appropriate height of the facet joint implant. In some embodiments, progressively larger trial gauges may be individually inserted into the facet joint until a trial gauge that provides a firm fit within the facet joint is found. In some embodiments, once the appropriate height of the facet joint has been determined, a rasp will be used to remove the cartilage and decorticate the facet joint surfaces. In some embodiments, the height of the rasp that will be used will be selected to be the same as the height of the trial gauge that had the appropriate fit within the facet joint.
In some embodiments, after the facet joint has been rasped, the implant can be secured to an inserter tool. The inserter tool, in some embodiments, includes a hollow shaft configured to abut against an end of the implant and a clamping mechanism configured to engage with one or more sides of the implant to hold the implant. In some embodiments, the clamping mechanism includes two or more movable arms that couple to features on the implant. The features may be, for example, small indents on opposite sides of the implant, according to some embodiments.
In some embodiments, once the inserter tool has been engaged with the implant, an impaction tool will be inserted inside of the hollow shaft of the inserter tool. In some embodiments, the impaction tool includes a tip that will engage with the implant. In some embodiments, the tip of the impaction tool is inserted into a channel in the implant when the impaction tool is seated inside of the inserter tool. In some embodiments, the impaction tool may be secured to the inserter tool via a threaded coupling at an end of the inserter tool. In some embodiments, the impaction tool is configured to stabilize the implant and will facilitate insertion of the implant into the facet joint. In some embodiments, the implant while engaged with the inserter tool and impaction tool, may be driven into the facet joint via light malleting. The malleting may be applied against an end surface of the impaction tool opposite the tip in some embodiments.
In some embodiments, the implant may be inserted into the facet joint until an end of the implant is flush with the opening of the facet joint. In some embodiments, the impaction tool can then be removed from the inserter tool and replaced with a cement introducer tool. In some embodiments, the cement introducer includes a hollow shaft for conducting bone cement from a bone cement source into the facet joint. In some embodiments, the cement introducer is inserted into the hollow shaft of the inserter tool and may also be secured to the inserter tool via a threaded coupling at an end of the inserter tool. In some embodiments, the cement introducer further includes a hollow tip that extends into a channel of the implant for conducting the bone cement into the implant.
In some embodiments, bone cement (e.g., PMMA, CPCs, HBCs, CSCs, etc.) can be introduced through the cement introducer and into the facet joint via a bone cement source coupled to the cement introducer. In some embodiments, the cement introducer includes a fitting for coupling directly or indirectly to the bone cement source. The bone cement source may include any conventional bone cement applicators or dispensers used in kyphoplasty and vertebroplasty. In some embodiments, the bone cement source includes, for example, a syringe containing the bone cement or a cannula and plunger system. In some embodiments, bone cement is channeled from the bone cement source, through the hollow shaft of the cement introducer, and into the facet joint. In some embodiments, the bone cement passes through a first channel in the implant and exits into the facet joint. In some embodiments, as the facet joint fills with bone cement, a portion of the bone cement is allowed to back flow and enter a second and/or third channel within the implant. In some embodiments, some of the bone cement may exit the second and/or third channels through openings located at an end of the implant. In some embodiments, some of the bone cement may exit the second and/or third channels through one or more openings on the lateral sides of the implant. In some embodiments, once bone cement is visualized within these channels, the introduction of bone cement may be ceased. Any bone cement that has extruded out of the facet joint or from the second and/or third channels of the implant may be removed. In some embodiments, after the introduction of the bone cement has ceased, the inserter tool and cement introducer may be removed from the implant. In some embodiments, the bone cement in the facet joint is allowed to fully cure and harden.
Referring now to the drawings in detail, there is shown in
As shown in
In some embodiments, lateral sides 108 and 110 are substantially planar and parallel such that width W is generally constant along the length of implant 100. In alternative embodiments, lateral sides 108, 110 may, at least partially, taper towards each other at distal end 104 such that width W decreases at distal end 104. In some embodiments, top side 112 and bottom side 114 may be, at least partially, parallel to each other. In some embodiments, top side 112 and bottom side 114 each may include substantially planar portions that are parallel to each other. In some embodiments, at least a portion of top side 112 and bottom side 114 may taper or curve towards each other at distal end 104. In an alternative embodiment illustrated in
In some embodiments, body 102 is constructed from a solid biocompatible material that is sufficiently rigid to withstand the compressive load within the facet joint without changing shape. In some embodiments, body 102 is made from a metal or metal alloy, for example, but not limited to, titanium, titanium alloys (e.g., Ti-6Al-4V), cobalt-chromium alloys, tantalum, or stainless steel. In other embodiments, body 102 is constructed from a ceramic material, for example, but not limited to, aluminum oxides or calcium phosphates. In other embodiments, body 102 may be made from or include a biocompatible thermoplastic material, for example, polyether ether ketone (PEEK). Composite materials that combine two or more different materials (e.g., metal/thermoplastic or metal/ceramic, etc.) may also be used to construct body 102, according to some embodiments. In some embodiments, body 102 is not composed of a bioabsorbable and/or biodegradable material.
Body 102 may be constructed via a process selected from additive manufacturing (e.g., 3D printing), machining (e.g., CNC machining), molding, casting, sintering, or other suitable manufacturing processes. In some embodiments, any external edges and/or corners of body 102 may be slightly rounded. In some embodiments, having rounded edges and/or corners may reduce the risk of gouging or fracturing bony portions of the facet joint during insertion of implant 100. In some embodiments, one or more surfaces of body 102 may be further processed by a surface treatment. The surface treatment may be applied to some or all of the external surfaces of body 102. In some embodiments, the surface treatment may be applied to body 102 in order to, for example, increase the contact area of implant 100 with the bone cement and/or bone tissue of the facet joint. In some embodiments, the surface treatment may be applied to body 102 to adjust or improve chemical and/or physical characteristics of implant 100, for example, corrosion resistance, wear resistance, hardness, etc. The surface treatment can include, for example, polishing, acid-etching, grit blasting, laser-etching, texturing, anodizing, oxidizing, plasma spraying, and/or chemical coating. In some embodiments, a surface treatment is applied to one or more portions of body 102 that is configured to promote or encourage bony ongrowth and/or ingrowth into implant 100. In some embodiments, implant 100 may have a porous surface. In some embodiments, the surface treatment includes applying a micro- or nano-scale texture onto a surface of body 102. For example, in some embodiments, micro- or nano-sized grooves or depressions may be formed on a surface of body 102 (e.g., by laser etching). In some embodiments, texturing on body 102 may include features that have dimensions (e.g., height, width, length, spacing, diameter, etc.) that are less than 100 μm. In some embodiments, the texturing may include features that have dimensions that are less than 50 μm. In some embodiments, the texturing may include features that have dimensions that are less than 10 μm. In some embodiments, the texturing may include features that have dimensions that are less than 5 μm. In some embodiments, the texturing may include features that have dimensions that are less than 1 μm.
Referring again to
In some embodiments, first channel 118 includes a circular cross-sectional shape and may have a generally smooth interior surface (e.g., unthreaded). In some embodiments, first channel 118, proximal opening 116, and distal opening 114 have a constant diameter selected to be any value from 1.75 mm to 3.5 mm. In some embodiments, the diameter is selected to be 0.25 mm to 0.5 mm less than height H of body 102.
In some embodiments, body 102 includes at least a second channel 120 that extends through the length of body 102 from a proximal opening 124 at proximal end 106 to a distal opening 122 at distal end 104. Second channel 120 may be generally parallel to first channel 118 according to some embodiments, and may be positioned at a location between first channel 118 and one of lateral sides 108 or 110. In some embodiments, second channel 120 does not intersect or communicate with first channel 118. In the illustrated embodiment, second channel 120 is positioned between first channel 118 and lateral side 108. In some embodiments, second channel 120 has the same cross-sectional shape as first channel 118. In other embodiments, second channel 120 has a cross-sectional shape that is different from first channel 118. In some embodiments, second channel 120 includes a non-circular cross-sectional shape. For example, in some embodiments, second channel 120 may have a rectangular cross-sectional shape as illustrated. In some such embodiments, each of proximal opening 124 and distal opening 122 may also be rectangular and have dimensions, for example, of 2 mm width×1.5-3.5 mm height. Other shapes are also possible for second channel 120, proximal opening 124, and distal opening 122.
In some embodiments, body 102 includes a third channel 126 that extends through the length of body 102 from a proximal opening 130 at proximal end 106 to a distal opening 128 at distal end 104. Third channel 126 may be generally parallel to first channel 118 and/or second channel 120 according to some embodiments and may be arranged symmetrically with respect to second channel 120 about axis A1. In other embodiments, third channel 126 is not necessarily parallel to first channel 118 and/or second channel 120. In some embodiments, second channel 120 and/or third channel 126 may each have a generally smooth interior surface (e.g., unthreaded). In the illustrated embodiment, third channel 126 is positioned between first channel 118 and lateral side 110. In some embodiments, third channel 120 does not intersect or communicate with first channel 118 and/or second channel 120. In some embodiments, third channel 126 has the same cross-sectional shape as first channel 118 and/or second channel 120. In other embodiments, third channel 126 has a cross-sectional shape that is different from first channel 118 and/or second channel 120. In some embodiments, third channel 126 includes a non-circular cross-sectional shape. For example, in some embodiments, third channel 126 may also have a rectangular cross-sectional shape as illustrated. In some such embodiments, each of proximal opening 130 and distal opening 128 may also be rectangular and have dimensions, for example, of 2 mm width×1.5-3.5 mm height. Other shapes are also possible for third channel 126, proximal opening 130, and distal opening 128.
In some embodiments, second channel 120 and/or third channel 126 are configured to serve as egress channels for the bone cement. In some embodiments, providing such egress channels may help prevent over-pressurization of the facet joint with bone cement. In some embodiments, as will be described further herein, after implant 100 is inserted into a facet joint, bone cement is introduced through proximal opening 116 of body 102, passes through first channel 118, and at least a portion of the bone cement exits first channel 118 at distal opening 114. An amount of the bone cement that exists distal opening 114 may fill spaces between implant 100 and the surfaces of the facet joint. In some embodiments, excess bone cement may be channeled from the facet joint through second channel 120 and/or third channel 126. In some embodiments, bone cement reenters implant 100 through distal openings 122 and/or 128, flows through second channel 120 and/or third channel 126, and exits through proximal openings 124 and/or 130.
In some embodiments, body 102 includes one or more lateral openings in lateral side 108 and/or lateral side 110. In some embodiments, the one or more lateral openings are in fluid communication with either second channel 120 or third channel 126. In some such embodiments, bone cement flowing through second channel 120 and/or third channel 126 may exit through the one or more lateral openings rather than proximal openings 124 and/or 130. In some embodiments, the one or more lateral openings may help distribute bone cement around the lateral sides of implant 100 within the facet joint.
In some embodiments, the cross-sectional areas of first, second, and/or third channels 118, 120, 126 may be selected based on the fluid properties of the bone cement (e.g., viscosity) such that, for example, the bone cement can flow readily through the channels and openings. For example, channels with larger cross-sectional area may be selected for use with bone cements having higher viscosity. In some embodiments, the cross-sectional areas of first, second, and/or third channels 118, 120, 126 may be sized such that the bone cement may flow through the channels without causing a reorientation of implant 100 during introduction of the bone cement material and/or without the bone cement becoming clogged in the channels or the openings connected thereto.
In some embodiments, implant 100 includes one or more features that are positioned and configured to engage with a tool to allow a user to manipulate implant 100. In some embodiments, the one or more features may be discrete surface features. The one or more features may include, for example, a recess, groove, notch, indentation, protrusion, lip, flange, or the like. In some embodiments, the one or more features are positioned at predetermined positions on one or more external surfaces of body 102. For example, the one or more features for engaging a tool may be located on top side 112, bottom side 114, distal end 104, proximal end 106, and/or lateral sides 108, 110. As shown in the illustrated embodiments of
In some embodiments, inserter tool 200 includes a grasping or clamping mechanism for engaging with implant 100. In the illustrated embodiments, inserter tool 200 includes a pair of arms 212a, 212b for holding onto implant 100. In some embodiments, arms 212a, 212b may be attached to and extend from shaft 202. In some embodiments, arms 212a, 212b are arranged on opposite sides of shaft 202 (e.g., diametrically opposed). In some embodiments, arms 212a, 212b are configured to move or pivot relative to shaft 202 and/or each other. In some embodiments, arms 212a, 212b can transition between a disengaged configuration shown in
In some embodiments, inserter tool 200 is configured to receive one or more additional tools. The one or more additional tools may be inserted through open proximal end 206 of shaft 202 in some embodiments. With reference now to
In some embodiments, shaft 302 includes an externally threaded section 310. Threaded section 310, in some embodiments is located at or proximate proximal end 306 of shaft 302. Threaded section 310 in some embodiments includes an external thread that is sized and positioned to couple with the internal thread of internally threaded section 210 of shaft 202 when impaction tool 300 is received within inserter tool 200, as particularly shown in
In some embodiments, impaction tool 300 further includes a head 308 that is fixed to shaft 302 at proximal end 306. Head 308 includes an end surface 308a is configured to receive a force to drive implant 100 into the facet joint during implantation. For example, a mallet, hammer, or other impact tool may be used to apply a driving force against end surface 308a when impaction tool 300 is engaged with inserter tool 200 to drive implant 100 into the facet joint. End surface 308a may be a flat surface, in some embodiments. In some embodiments, head 308 is positioned to abut against handle or flange 208 of inserter tool 200 when impaction tool 300 is fully coupled with inserter tool 200.
In further embodiments, impaction tool 300 includes a tip portion 312 opposite head 308. In some embodiments, tip portion 312 extends from distal end 304 of shaft 302 and has a diameter that is smaller than the diameter of shaft 302. In some embodiments, tip portion 312 is sized to be inserted into first channel 118 of implant 100 (e.g., via proximal opening 116) when impaction tool 300 is inserted into inserter tool 200 and may have a cylindrical shape. In some embodiments, tip portion 312 assists in stabilizing implant 100 during implantation by restricting movement of implant 100 relative to inserter tool 200 and impaction tool 300. For example, in some embodiments, tip portion 312 inserted into first channel 118 may assist in keeping implant 100 axially aligned with impaction tool 300 and inserter tool 200 during implantation.
In some embodiments, after implant 100 has been positioned within the facet joint, impaction tool 300 may be withdrawn from inserter tool 200. In some embodiments, impaction tool 300 may be withdrawn by rotating impaction tool 300 relative to inserter tool 200 in a direction to unscrew impaction tool 300 from inserter tool 200 and disengage the external thread of threaded portion 310 from the internal thread of threaded portion 210. In some embodiments, after impaction tool 300 has been removed from inserter tool 200, a separate tool may be received by inserter tool 200 to facilitate the introduction of bone cement into the facet joint.
Referring now to
In some embodiments, shaft 402 includes an externally threaded section 410. Threaded section 410, in some embodiments is located at or proximate proximal end 406 of shaft 402. Threaded section 410 in some embodiments includes an external thread that is sized and positioned to couple with the internal thread of internally threaded section 210 of shaft 202 when cement introducer 400 is received within inserter tool 200. In some such embodiments, cement introducer 400 may be slid into shaft 202 via open proximal end 206 until externally threaded section 410 engages with internally threaded section 210, at which point cement introducer 400 must be rotated in a first rotational direction relative to shaft 202 to advance cement introducer 400 in the axial direction. In some embodiments, when cement introducer 400 is fully coupled with inserter tool 200 (e.g., as shown in
In further embodiments, cement introducer 400 includes a hollow tip portion 412 that extends from distal end 404 of shaft 402 and has a diameter that is smaller than the diameter of shaft 402. In some embodiments, tip portion 412 is sized to be inserted into first channel 118 of implant 100 (e.g., via proximal opening 116) when cement introducer 400 is inserted into inserter tool 200. In some embodiments, hollow tip portion 412 is configured to conduct bone cement from shaft 402 into implant 100.
In some embodiments, cement introducer 400 includes a port 414 that extends from shaft 402 at proximal end 406. Port 414, in some embodiments, is configured to couple with a bone cement source (e.g., syringe 500) to receive bone cement therefrom. In some embodiments, port 414 includes a fitting that is configured to form a fluid-tight connection to the bone cement source. For example, in some embodiments port 414 may include a Luer lock fitting, threaded fitting, quick connect fitting, or other fitting. In some embodiments, cement introducer 400 further includes a flange 408 that is positioned to abut against handle or flange 208 of inserter tool 200 when cement introducer 400 is fully coupled with inserter tool 200. In some embodiments, flange 408 is axially positioned between proximal end 406 and port 414.
As illustrated in
In some embodiments, after implant 100 is positioned within the facet joint, bone cement material is dispensed from the bone cement source and travels through port 414, shaft 402, and hollow tip portion 412 of cement introducer 400 into implant 100.
In some embodiments, at least a portion of the bone cement material 600 may flow back into implant 100 after exiting first channel 118. In some embodiments, bone cement material 600 may flow back into implant 100 via distal openings 122 and 128 of second and third channels 120 and 126, respectively. In some embodiments, second channel 120 and third channel 130 are configured to serve as egress channels for the bone cement material 600. In some embodiments, providing such egress channels may help prevent over-pressurization of the facet joint with the bone cement material 600. In some embodiments, excess bone cement material 600 that reenters implant 100 through distal openings 122 and/or 128 may flow through second channel 120 and/or third channel 126, and exit implant 100 through proximal openings 124 and/or 130. In some embodiments, where implant 100 includes one or more lateral openings 132a, 132b, 134a, 134b, bone cement flowing through second channel 120 and/or third channel 126 may exit implant 100 through the one or more lateral openings rather than proximal openings 124 and/or 130. In some embodiments, the one or more lateral openings 132a, 132b, 134a, 134b may help distribute bone cement around the lateral sides of implant 100 within the facet joint. In some embodiments, once bone cement material 600 is observed exiting second channel 120 and/or third channel 126, the introduction of the bone cement material 600 from the bone cement source may be ceased, and any bone cement material that has extruded out of the facet joint or implant 100 from proximal openings 124, 130 should be removed. In some embodiments, after the introduction of the bone cement material 600 has ceased, the cement introducer 400 and inserter tool 200 may be removed from implant 100 and the bone cement material 600 is allowed to cure and harden in the facet joint around implant 100.
In some embodiments, the facet joint may require certain preparation prior to implantation of implant 100. In some embodiments, a dorsal aspect of the facet joint capsule may be removed in order to provide an opening to the facet joint. In some such embodiments, electrocautery may be used to remove the dorsal aspect of the facet joint capsule. In further embodiments, once the opening of the facet joint is exposed, one or more trial gauges of predetermined size may be introduced into the facet joint in order to dilate the opening of the facet joint and to determine the appropriate height of implant 100 to be inserted.
In some embodiments, surfaces of the facet joint may be rasped prior to inserting implant 100. In some embodiments, a rasp is used to remove cartilage and decorticate the facet joint surfaces.
In some embodiments, two or more components described herein may be assembled as a kit. In some embodiments, a kit according to the present disclosure may include at least one implant 100 and at least one of the tools as described herein (e.g., inserter tool 200, impaction tool 300, cement introducer 400, trial gauges 700a-700c, or rasps 800a-800c). In some embodiments, a kit may include at least one implant 100 and inserter tool 200. In some embodiments, a kit may include at least one implant 100, inserter tool 200, and impaction tool 300. In some embodiments, a kit may include at least one implant 100, inserter tool 200, impaction tool 300, and cement introducer 400. In some embodiments, a kit may include at least one implant 100, inserter tool 200, and cement introducer 400. In some embodiments, kits according to the present disclosure may include a plurality of implants 100. In some embodiments, the plurality of implants 100 may have the same or different shapes and/or sizes. In further embodiments, a kit may include a plurality of trial gauges 700a-700c and rasps 800a-800c having different sizes. In yet further embodiments, a kit may include a bone cement source, for example, syringe 500 or other bone cement dispenser. Two or more components of a kit may be packaged together according to some embodiments. In some embodiments, implant 100 and any of the tools described herein (e.g., inserter tool 200, impaction tool 300, cement introducer 400, trial gauges 700a-700c, or rasps 800a-800c) are sterilized prior to packaging. In some embodiments, implant 100 and any of the tools described herein (e.g., inserter tool 200, impaction tool 300, cement introducer 400, trial gauges 700a-700c, or rasps 800a-800c) are sterilized prior to use.
It should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. It should also be apparent that individual elements identified herein as belonging to a particular embodiment may be included in other embodiments of the invention. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, and composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure herein, processes, machines, manufacture, composition of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention.
This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63/109,904, filed Nov. 5, 2020, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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63109904 | Nov 2020 | US |