Patent Description:
Treatment of spinal disorders, such as degenerative disc disease, disc herniations, scoliosis or other curvature abnormalities, and fractures, often requires surgical treatments. For example, spinal fusion may be used to limit motion between vertebral members. As another example, implants may be used to preserve motion between vertebral members.

Surgical treatment typically involves the use of longitudinal members, such as spinal rods. Longitudinal members may be attached to the exterior of two or more vertebral members to assist with the treatment of a spinal disorder. Longitudinal members may provide a stable, rigid column that helps bones to fuse, and may redirect stresses over a wider area away from a damaged or defective region. Also, rigid longitudinal members may help in spinal alignment.

Screw assemblies may be used to connect a longitudinal member to a vertebral member. A screw assembly may include a pedicle screw, hook, or other connector and/or a set screw, among other components. A pedicle screw can be placed in, above and/or below vertebral members that were fused, and a longitudinal member can be used to connect the pedicle screws which inhibits or controls movement. A set screw can be used to secure the connection of a longitudinal member and a pedicle screw, hook or other connector. However, the connection force and continued integrity of the connection between a longitudinal member and a pedicle screw or other connector can be challenging to monitor during and after implantation. In addition, it is difficult to monitor that an appropriate force is maintained between a set screw and a longitudinal member. Conventional load assemblies and/or screw assemblies are not capable of sensing and wirelessly transmitting the connection force between a longitudinal rod and a pedicle screw installed within a patient. Furthermore, they cannot continuously monitor and maintain a secure connection on relatively long time frames.

A load sensing assembly for a spinal implant according to the preamble of claim <NUM> is, e.g., known from <CIT>.

<CIT> discloses a load sensing assembly for a spinal implant.

The invention provides a load sensing assembly for a spinal implant according to claim <NUM>.

The embodiments which form part of the invention are illustrated in the <FIG>.

The examples shown in the other figures do not form part of the invention but represent background art that is useful for understanding the invention.

References to "embodiments" throughout the description which are not under the scope of the appended claims merely represent possible exemplary executions and are therefore not part of the present invention.

The exemplary embodiments of the surgical system and related methods of use (not claimed) disclosed are discussed in terms of medical devices for the treatment of musculoskeletal disorders and more particularly, in terms of a vertebral fixation screws, including for example pedicle screws, as well as hooks, cross connectors, offset connectors and related systems for use during various spinal procedures or other orthopedic procedures and that may be used in conjunction with other devices and instruments related to spinal treatment, such as rods, wires, plates, intervertebral implants, and other spinal or orthopedic implants, insertion instruments, specialized instruments such as, for example, delivery devices (including various types of cannula) for the delivery of these various spinal or other implants to the vertebra or other areas within a patient in various directions, and/or a method or methods for treating a spine, such as open procedures, mini-open procedures, or minimally invasive procedures. Exemplary prior art devices that may be modified to include the various embodiments of load sensing systems include, for example, <CIT> and <CIT>.

The present disclosure may be understood more readily by reference to the following detailed description of the embodiments taken in connection with the accompanying drawing figures, which form a part of this disclosure.

In some embodiments, as used in the specification and including the appended claims, the singular forms "a," "an," and "the" include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" or "approximately" one particular value and/or to "about" or "approximately" another particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It is also understood that all spatial references, such as, for example, horizontal, vertical, top, upper, lower, bottom, left and right, are for illustrative purposes only and can be varied within the scope of the disclosure. For example, the references "upper" and "lower" are relative and used only in the context to the other, and are not necessarily "superior" and "inferior". Generally, similar spatial references of different aspects or components indicate similar spatial orientation and/or positioning, i.e., that each "first end" is situated on or directed towards the same end of the device. Further, the use of various spatial terminology herein should not be interpreted to limit the various insertion techniques or orientations of the implant relative to the positions in the spine.

The following discussion includes a description of a vertebral pedicle screw system and related components and methods of employing the vertebral pedicle screw in accordance with the principles of the present disclosure. Reference is made in detail to the exemplary embodiments of the present disclosure, which are illustrated in the accompanying figures.

The components of the vertebral pedicle screw system described herein can be fabricated from biologically acceptable materials suitable for medical applications, including metals, synthetic polymers, ceramics and bone material and/or their composites. Some ceramics may be formed of Zirconia 3Y-TZP and/or a Zirconia toughed alumina (ZTA), for example. Additionally, various the components of the vertebral pedicle screw system, individually or collectively, can be fabricated from materials such as stainless steel alloys, commercially pure titanium, titanium alloys, Grade <NUM> titanium, super-elastic titanium alloys, cobalt-chrome alloys, stainless steel alloys, superelastic metallic alloys (e.g., Nitinol, super elasto-plastic metals, such as GUM METAL®), ceramics and composites thereof such as calcium phosphate (e.g., SKELITE™), thermoplastics such as polyaryletherketone (PAEK) including polyetheretherketone (PEEK), polyetherketoneketone (PEKK) and polyetherketone (PEK), carbon-PEEK composites, PEEK-BaSO<NUM> polymeric rubbers, polyethylene terephthalate (PET), fabric, silicone, polyurethane, silicone-polyurethane copolymers, polymeric rubbers, polyolefin rubbers, hydrogels, semi-rigid and rigid materials, elastomers, rubbers, thermoplastic elastomers, thermoset elastomers, elastomeric composites, rigid polymers including polyphenylene, polyamide, polyimide, polyetherimide, polyethylene, epoxy, bone material including autograft, allograft, xenograft or transgenic cortical and/or corticocancellous bone, and tissue growth or differentiation factors, partially resorbable materials, such as, for example, composites of metals and calcium-based ceramics, composites of PEEK and calcium based ceramics, composites of PEEK with resorbable polymers, totally resorbable materials, such as, for example, calcium based ceramics such as calcium phosphate, tri-calcium phosphate (TCP), hydroxyapatite (HA)-TCP, calcium sulfate, or other resorbable polymers such as polyaetide, polyglycolide, polytyrosine carbonate, polycaroplaetohe and their combinations.

Various components of the vertebral pedicle screw system may be formed or constructed material composites, including the above materials, to achieve various desired characteristics such as strength, rigidity, elasticity, compliance, biomechanical performance, durability and radiolucency or imaging preference. The components of the present vertebral pedicle screw system, individually or collectively, may also be fabricated from a heterogeneous material such as a combination of two or more of the above-described materials. The components of the vertebral pedicle screw system may be monolithically formed, integrally connected or include fastening elements and/or instruments, as described herein. The components of the vertebral pedicle screw system may be formed using a variety of subtractive and additive manufacturing techniques, including, but not limited to machining, milling, extruding, molding, 3D-printing, sintering, coating, vapor deposition, and laser/beam melting. Furthermore, various components of the vertebral pedicle screw system may be coated or treated with a variety of additives or coatings to improve biocompatibility, bone growth promotion or other features. To the extent the plate is entirely or partially radiolucent, it may further include radiographic markers made, for example of metallic pins, at one or both ends, on each corner of the ends, and/or along the length of the implant in various locations including near the center of the assembly.

The vertebral pedicle screw system may be employed, for example, with a minimally invasive procedure, including percutaneous techniques, mini-open and open surgical techniques to deliver and introduce instrumentation and/or one or more spinal implants at a surgical site within a body of a patient, for example, a section of a spine. In some embodiments, the vertebral pedicle screw system may be employed with surgical procedures, as described herein, and/or, for example, corpectomy, discectomy, fusion and/or fixation treatments that employ spinal implants to restore the mechanical support function of vertebrae. In some embodiments, the pedicle screw system may be employed with surgical approaches, including but not limited to: anterior lumbar interbody fusion (ALIF), direct lateral interbody fusion (DLIF), oblique lateral lumbar interbody fusion (OLLIF), oblique lateral interbody fusion (OLIF), transforaminal lumbar Interbody fusion (TLIF), posterior lumbar Interbody fusion (PLIF), various types of posterior or anterior fusion procedures, and any fusion procedure in any portion of the spinal column (sacral, lumbar, thoracic, and cervical, for example).

Referring generally to <FIG>, an example set screw assembly and anchoring assembly is illustrated. <FIG> may illustrate an example anchoring assembly and longitudinal member according to an embodiment. As illustrated in <FIG>, an anchoring assembly may include a screw <NUM> and an anchoring member <NUM>. The screw <NUM> may have an elongated shape with a first end mounted within a vertebral member <NUM> and a second end extending outward above the vertebral member <NUM>. The anchoring member <NUM> may be configured to operatively connect to the second end of the screw <NUM> and may be movably connected to the screw <NUM> to accommodate the longitudinal member <NUM> positioned at various angular positions. The anchoring member <NUM> may include a channel <NUM> sized to receive the longitudinal member <NUM>. A set screw <NUM> may attach to the anchoring member <NUM> to capture the longitudinal member <NUM> within the channel <NUM>.

<FIG> illustrates an example exploded view of a screw assembly and longitudinal member according to an embodiment. As shown by <FIG>, anchoring member <NUM> provides a connection between the screw <NUM> and longitudinal member <NUM>. Anchoring member <NUM> includes a first end <NUM> that faces towards the vertebral member <NUM>, and a second end <NUM> that faces away. A chamber may be positioned between the first and second ends <NUM>, <NUM> and may be sized to receive at least a portion of the screw <NUM>. In various embodiments, a first end <NUM> may be considered a base portion of an anchoring member <NUM>, and a second end <NUM> may be considered a head portion of an anchoring member.

The second end <NUM> of the anchoring member <NUM> may include a channel <NUM> sized to receive the longitudinal member <NUM>. Channel <NUM> terminates at a lower edge <NUM> that may include a curved shape to approximate the longitudinal member <NUM>. Threads <NUM> may be positioned towards the second end <NUM> to engage with the set screw <NUM>. In one embodiment as illustrated in <FIG>, the threads <NUM> are positioned on the interior of the anchoring member <NUM> facing towards the channel <NUM>. In another embodiment, the threads <NUM> may be on the exterior of the anchoring member <NUM>. An interior of the anchoring member <NUM> may be open between the first and second ends <NUM>, <NUM>.

In various embodiments, an anchoring member <NUM> may include a washer <NUM>. A washer <NUM> may be generally cylindrical and may have a hole <NUM> there through. As illustrated by <FIG> a washer <NUM> may be positioned near a first end <NUM> of an anchoring member <NUM>. A screw <NUM> may engage with an anchoring member <NUM> via positioning through the hole <NUM> of a washer <NUM>. A washer <NUM> may include recessed portions which may be configured to accommodate placement of a longitudinal member <NUM> therein. The use of a washer <NUM> in connection with an anchoring member <NUM> may help minimize misalignment of the longitudinal member within the anchoring member.

In an embodiment, set screw <NUM> attaches to the anchoring member <NUM> and captures the longitudinal member <NUM> within the channel <NUM>. Set screw <NUM> may include an antenna <NUM>, which will be explained in further detail below. As illustrated in <FIG>, the set screw <NUM> may be sized to fit within the interior of the channel <NUM> and include exterior threads <NUM> that engage threads <NUM> on the anchoring member <NUM>. Additionally, a cover portion <NUM> may contact longitudinal member <NUM> when the set screw <NUM> is rotatably positioned into a closed contact position above longitudinal member <NUM> and within anchoring member <NUM>. A driving feature <NUM> may be positioned on a top side to receive a tool during engagement with the anchoring member <NUM>, e.g., a screwdriver or the like having a corresponding head. In some embodiments, the set screw <NUM> may be mounted on an exterior of the anchoring member <NUM>. Set screw <NUM> may include a central opening that partially extends into set screw <NUM> from drive feature <NUM> towards the second end <NUM>. For example, the drive feature <NUM> may be a recessed portion having a covered bottom portion and circumferential side walls such that the drive feature <NUM> portion of set screw <NUM> does not fully extend through the set screw <NUM> from the top to the bottom. Threads <NUM> are positioned on an outside surface of the set screw <NUM> and engage with the threads <NUM> on the anchoring member <NUM>. The set screw <NUM> and anchoring member <NUM> may be constructed for the top side of the set screw <NUM> to be flush with or recessed within the second end <NUM> when mounted with the anchoring member <NUM>. For example, a common plane crossing over a top surface of antenna <NUM> and a top surface of second end <NUM>.

Although <FIG> and <FIG> illustrate an exemplary multi-axial tulip-head pedicle screw it shall be understood that other types of anchoring members may be used within the scope of this disclosure. For example, fixed head screws or screws having differently shaped heads may be used. As another example, a hook member, a cross-link connector, an offset connector, or a hybrid hook-screw member may be used as well.

<FIG> illustrates an exploded view of an example set screw <NUM>, and <FIG> illustrates set screw <NUM> after being fully assembled according to an embodiment. As illustrated, set screw <NUM> may include an antenna <NUM>, a body portion 50a, and a cover portion <NUM>. Body portion 50a may include an outside surface with threads and a lower body cavity portion 50b defined by a depth and interior radius that corresponds to a depth and exterior radius of cover portion <NUM>. For example, cover portion <NUM> may be dimensioned to fit inside at least a portion of body cavity portion 50b such that only a protrusion 55a extends from a lowermost surface of body portion 50a. Protrusion 55a may directly contact longitudinal rod <NUM> when set screw <NUM> is fully secured within anchoring member <NUM>.

<FIG> illustrates a cross section drawing of an example set screw <NUM> taken along line C<NUM>-C<NUM> of <FIG>. In the example illustration, antenna <NUM> may be disposed on a top portion of main body 50a and cover portion <NUM> may be disposed in a lower cover cavity 54a of main body 50a. In example embodiments, antenna <NUM>, may be a radio frequency identification (RFID) coil, a near field-communication (NFC) antenna or other short-range communication transmitter and/or receiver. Antenna <NUM> may include an axisymmetric coil 300a stacked on a ferrite base 300f and a carrier 300c. The axisymmetric coil 300a, ferrite 300f, and carrier 300c may be surrounded by an overmold <NUM>. An example overmold <NUM> may be an insulator material, such as a thermoplastic material like Polyether ether ketone (PEEK). In some embodiments, antenna <NUM> may be fixedly coupled to a top portion of set screw <NUM> and in other embodiments, antenna <NUM> may be removably coupled to a top portion of set screw <NUM>, e.g., by mechanical means such as corresponding threads or snap locking features.

In an example embodiment, set screw <NUM> may include a drive feature <NUM> that passes through antenna <NUM> and into a cavity of set screw <NUM> that is defined by interior sidewalls of set screw <NUM> and a bottom sidewall 54c. Antenna <NUM> may also include a flexible electronics component, such as, for example, a flex circuit or one or more electrical circuits operably connected to the electronics components <NUM> via a connecting member <NUM>. For instance, as shown in <FIG>, the connecting member <NUM> may be connected to both the antenna <NUM> and the electronics components <NUM>. The connecting member <NUM> may be positioned perpendicularly to both the antenna <NUM> and the electronics components <NUM>. In an example embodiment, connecting member <NUM> may pass from antenna <NUM> through a through hole 50t passing through main body 50a and into electronics cavity 54b for housing electronics components <NUM>. In an example embodiment, through hole 50t may be filled with an insulating material, for example the same or substantially same material as the overmold <NUM>. However, it shall be understood that through hole 50t may be filed with any suitable material that is effective at sealing through hole 50t, e.g., an epoxy or the like.

Example, electronics components <NUM> may include a series of electronic components in electrical communication with one another. For example, a mainboard or other suitable printed circuit board (PCB) 55p may be electrically connected to an application specific integrated circuit (ASIC) 55a, a charge storage capacitor 55c, and various mechanical electrical sensors or micro electromechanical systems (MEMs) <NUM>. Example MEMs <NUM> may include a strain gauge, and/or a temperature gauge. However, other MEMs sensors may be incorporated in other embodiments depending on the particular use case. In some embodiments, electronics components <NUM> may be an prepackaged self-contained unit that is attached to cover <NUM> by, e.g., adhesive, chemical, mechanical or cement bonding. Additionally, electronics components <NUM> may include a non-transitory data store (not illustrated) according to an embodiment, e.g., a memory cell such as a solid state memory cell or the like. The non-transitory memory data store may store information and/or data from various MEMs sensors <NUM>, for example. A non-transitory data store may be used to store various information. For example, one or more measurements of a strain gauge <NUM> may be stored in memory. As another example, a unique identifier associated with a load sensing assembly, a component thereof, or a set screw <NUM> may be stored in memory. Additional and/or alternate information or types of information may be stored as is consistent with this disclosure. Additionally, in some embodiments, electronics components <NUM> may be coated in a material to prevent and/or suppress corrosion, e.g., a conformal coating, an epoxy coating, aerosol coating, or the like.

In various embodiments, electronics components <NUM> may be fixedly coupled to cover portion <NUM> and have a connecting terminal or connecting portion <NUM> extending therefrom. The connecting terminal or connecting portion <NUM> may be suitably connected to a lead wire extending from antenna <NUM>. For example, as shown in <FIG>, electronics components <NUM> are in electrical communication with antenna <NUM> by way of connecting portion <NUM>. In various embodiments, connecting member <NUM>, antenna <NUM>, and/or electronics components <NUM> may be constructed integrally or may be separately constructed and attached together in any suitable manner, such as for example by adhesive, chemical, mechanical or cement bonding.

In at least one embodiment, electronics components <NUM> may be configured as a load sensing assembly. A load sensing assembly may include one or more electronics components <NUM> and/or a strain gauge <NUM>, such as for example a silicon strain gauge. A strain gauge <NUM> may be a device that measures strain on an object. For instance, a strain gauge <NUM> may measure a force between a set screw and a longitudinal member when the set screw is engaged with an anchoring member. A strain gauge <NUM> may include one or more sensors or sensor nodes that measure strain, force, resistance, deflection, load and/or the like.

As illustrated in <FIG>, a load sensing assembly may be configured to be coupled to a set screw <NUM>. For example, cover <NUM> including electronics components <NUM> may be coupled to set screw <NUM>. In at least one embodiment, cover <NUM> including pre-installed electronics components <NUM> are installed/inserted into the bottom portion of main body 50a in the corresponding lower cover cavity 54a. In at least one embodiment, lower cover cavity 54a may be dimensioned such that exterior side wall portions of cover <NUM> directly contact interior sidewall portions of cover cavity 54a. For example, lower cover cavity 54a may be defined by a radius of a first circle that corresponds to a radius of cover <NUM>. However, in other embodiments, cover <NUM> may be oval shaped, hexagonal, or square and in those embodiments cover cavity 54a has a corresponding geometry imparting the same, substantially the same, or similar functional arrangement. Additionally, by installing cover <NUM> including pre-installed electronics components <NUM> into a body portion of set screw <NUM> the electronics components <NUM> are housed with electronics cavity 54b. Electronics cavity may open up to lower cover cavity 54a and may be enclosed at a top portion corresponding to the bottom sidewall 54c of drive interface <NUM>. For example, bottom sidewall 54c may also function as a top surface, or ceiling, of electronics cavity 54b. It shall be understood that the relative position of bottom sidewall 54c may be lowered to accommodate different drivers interactive with drive feature <NUM> or may be raised to accommodate differently sized electronics components <NUM>. In an embodiment, the electronics cavity 54b may have a height of about twice the height of cover cavity 54a. Cover cavity 54a may be defined by a radius of a first circle in the horizontal direction and electronics cavity 54b may be defined by the radius of a second circle in the horizontal direction. In at least one embodiment, the radius of the first circle (corresponding to the cover cavity 54a) may be greater than the radius of the second circle (corresponding to the electronics cavity 54b). For example, an inset step may be provided where the cover cavity 54a and electronics cavity 54b meet one another relative to the main body 50a.

Consistent with previous disclosure, a strain gauge <NUM> may be operably connected, for example by adhesive, cement, mechanical or chemical bonding, to the electronics components <NUM>. For instance, a strain gauge <NUM> may be operably connected to the electronics components <NUM> via the bottom surface <NUM> of the electronics components <NUM>. A strain gauge <NUM> may be connected to an inside surface 55b of cover <NUM> in any suitable manner including, without limitation, via an adhesive bonding agent. Strain gauge <NUM> may be situated in this way to detect strain in a curved contact portion of 55a acting against longitudinal rod <NUM> (see <FIG> and <FIG>).

<FIG> illustrates an example set screw <NUM> at a first assembly stage with a pre-installed antenna <NUM>. <FIG> illustrates a bottom view of an example set screw <NUM> after cover portion <NUM> has been fixedly attached to example set screw <NUM> of <FIG>. In at least one embodiment, cover portion <NUM> is fixedly attached to set screw <NUM> by a continuous weld 55w (see also <FIG>). The continuous weld 55w may be any type of weld, for example a fillet weld or a butt joint weld. The continuous weld may be performed by any method, for example laser welding, gas welding, electron beam welding, etc. In some embodiments, a series of tack welds (not illustrated) may be performed at discrete intervals in substantially the same way and at substantially the same locations. At least one advantage to fixedly coupling cover portion <NUM> as previously disclosed is that electronics components <NUM> may be securely protected by virtue of being in a fully sealed cavity, for example an airtight and water tight cavity, i.e., a hermetically sealed cavity.

<FIG> illustrates a side view of an example set screw <NUM> showing the interior electronic components <NUM> in skeleton outlining. As illustrated in <FIG>, the antenna <NUM> may circumferentially surround at least a portion of the exterior of the set screw <NUM>. For example, antenna <NUM> may cover, at least partially, a top surface of set screw <NUM>. In some embodiments, antenna <NUM> may cover the entire top surface (uppermost surface) of set screw <NUM>. For example, antenna <NUM> may circumferentially surround a top surface of set screw <NUM>. In other embodiments, the antenna <NUM> may be positioned at least partially inside of the central opening of a set screw (not illustrated). For example still, the antenna may be located, at least in part, proximate to a top portion of set screw <NUM>. Consistent with the above disclosure, in certain embodiments, the strain gauge <NUM> may be connected to cover <NUM> such that it is positioned to measure a force between the set screw <NUM> and a longitudinal rod <NUM> (see <FIG> and <FIG>) when the set screw <NUM> engages with an anchoring member, for example protrusion 55a. Additionally or alternatively, other MEMs sensors, such as a temperature gauge for example, may be positioned to discern a body temperature of a patient in the same, similar, or substantially the same way. In at least one embodiment, a temperature sensor is positioned to discern a body temperature of a patient in the region of the longitudinal rod, and in others a temperature sensor is positioned to discern a body temperature of a patient in a region adjacent a threaded portion of set screw <NUM> that is directly exposed to patient tissue (i.e., not a portion contacting longitudinal rod <NUM>).

In various embodiments, one or more measurements obtained by strain gauge <NUM> may be stored by an integrated circuit of a corresponding load sensing assembly such as, for example, in non-transitory computer readable memory as disclosed above. In turn, antenna <NUM> and/or electronics components <NUM> may be interrogated by a reader. For instance, an RFID chip may be read by an RFID reader. As another example, an NFC chip may be read by or may otherwise communicate with an NFC reader or other NFC-enabled device. In other embodiments, a custom protocol may be used, for example a <NUM> inductive link. Example readers may include at least one antenna for receiving and/or transmitting data with antenna <NUM> of set screw <NUM>, a central processing unit CPU, and a non-transitory computer readable medium (such as a memory unit or memory cell storing programmable computer implemented instructions). In at least one embodiment, an electromagnetic reader (first reader) may transmit electromagnetic energy to set screw <NUM> to power electronic components <NUM> and an RFID reader or an NFC reader (second reader) may be used separately to read, acquire, and/or interpret data received from antenna <NUM>. A reader may interrogate an integrated circuit when in a certain proximity to the integrated circuit. In certain embodiments, a reader may interrogate an integrated circuit that has been implanted into a patient as part of a set screw or anchoring member assembly. In other embodiments, an integrated circuit may communicate with a reader or other electronic device without being interrogated.

An integrated circuit of electronics components <NUM> may transmit one or more measurements to the reader. This transmission may occur in response to being interrogated by the reader, or the transmission may be initiated by the integrated circuit. The reader may receive the transmitted measurements, and may cause at least a portion of the measurements to be displayed to a user. For instance, a physician may use a reader to interrogate an RFID chip of a patient's implant. The reader may include a display, or may be in communication with a display device, which may display at least a portion of the measurements received from the RFID chip.

Electronic components <NUM> may include a passive integrated circuit. An example passive integrated circuit may refer to an arrangement where electronic components <NUM> do not include an internal power source. For example, electronic components <NUM> may be powered by energy transmitted from a reader. With respect to electronic components <NUM> having a passive integrated circuit, the passive integrated circuit may not transmit information until interrogated by a reader. For example, a reader may transmit electromagnetic energy directed at the passive integrated circuit to wirelessly power the passive integrated circuit. At least two advantages of using an integrated circuit that does not include a battery or require a battery is reliability, and reduction in space within the cavity 54b that houses the electronic components <NUM> forming a passive integrated circuit.

In various embodiments, one or more sensors of electronic components <NUM> may transmit information by directly modulating a reflected signal, such as an RF signal. The strain gauge <NUM> sensors may form a Wireless Passive Sensor Network (WPSN), which may utilize modulated backscattering (MB) as a communication technique. External power sources, such as, for example, an RF reader or other reader, may supply a WPSN with energy. The sensor(s) of the WPSN may transmit data by modulating the incident signal from a power source by switching its antenna impedance.

In another embodiment, an integrated circuit may be active, meaning that the chip is battery-powered and capable of broadcasting its own signal. An active integrated circuit may transmit information in response to be interrogated by a reader, but also on its own without being interrogated. For instance, an active integrated circuit may broadcast a signal that contains certain information such as, for example, one or more measurements gathered by an associated strain gauge. An active integrated circuit may continuously broadcast a signal, or it may periodically broadcast a signal. Power may come from any number of sources, including, for example, thin film batteries with or without encapsulation or piezo electronics.

One or more measurements received from a load sensing assembly may be used to make determinations of the condition of a spinal implant and/or treatment of a spinal disorder. For instance, proper placement of a longitudinal member, set screw and/or anchoring member may result in an acceptable range of force measurements collected by a strain gauge of a load sensing assembly. Measurements outside of this range may indicate a problem with the placement or positioning of a longitudinal member, set screw and/or anchoring member such as, for example, loosening of a set screw and/or anchoring member, longitudinal member failure, construct failure, yield or fracture/breakage, improper torque, breakage of the bone segment or portion, the occurrence of fusion or amount of fusion, and/or the like. In these instances, the reader may contain a range of pre-determined acceptable values corresponding to the strain gauge <NUM> and/or other MEMs sensors. If the actual measured reading of the strain gauge <NUM> and/or other MEMs sensors falls outside of the range, the reader may notify an end user, a hospital management system, and/or the patient. For example, a patient may continuously or regularly monitor the actual measured readings of set screw <NUM> on an outpatient basis with a reader. In some embodiments, a reader may be configured to relay information received from antenna <NUM> to a secondary processing component such as an external display, computer, server, hospital management system, or other type of data processing equipment. The secondary processing component may process information received by the reader from antenna <NUM> via a processor, controller, and memory configured to execute programmable computer implemented instructions. In this way, disclosed systems increase the likelihood that a patient can detect a malfunction, such as loosing of a set screw <NUM> and/or interbody system (see <FIG> and <FIG>), before catastrophic failure.

One or more tools or instruments may include a reader which may be used to gather information from one or more integrated circuits of electronic components <NUM> during or in connection with a procedure. For instance, a torque tool (not illustrated) may be used to loosen or tighten set screw <NUM>. A torque tool may include a reader, or may be in communication with a reader, such that a user of the torque tool is able to obtain, in substantially real time, one or more measurements relating to the set screw <NUM> and longitudinal rod <NUM> placement that are measured by a strain gauge <NUM> of a load sensing assembly of the set screw <NUM> via the tool. For instance, as a user is applying torque to a set screw <NUM>, the user may see one or more force measurements between the set screw <NUM> and the longitudinal member in order to determine that the positioning of the set screw <NUM> and/or longitudinal member is correct and that the proper force is being maintained. In certain embodiments, a tool or instrument may include a display device (not illustrated) on which one or more measurements may be displayed. In other embodiments, a tool or instrument may be in communication with a display device (not illustrated), and may transmit one or more measurements for display on the display device via a communications network.

In some embodiments, an electronic device, such as a reader or an electronic device in communication with a reader (not illustrated), may compare one or more measurements obtained from an integrated circuit to one or more acceptable value ranges. If one or more of the measurements are outside of an applicable value range, the electronic device may cause a notification to be made. For instance, an electronic device may generate an alert for a user, and cause the alert to be displayed to the user via a display device. Additionally or alternatively, an electronic device may send an alert to a user such as via an email message, a text message, a notification, or otherwise.

An integrated circuit of electronics components <NUM> may store a unique identifier associated with the components to which the load sensing assembly corresponds. For example, an integrated circuit of electronics components <NUM> for a set screw <NUM> may store a unique identifier associated with the set screw <NUM> and/or cover <NUM>. For example, when a reader interrogates an integrated circuit, the integrated circuit may transmit a unique identifier for a component that is stored by the integrated circuit to the reader. Having access to a unique identifier for a component may help a user ascertain whether the measurements that are being obtained are associated with the component of interest. Also, having access to a unique identifier for a component may help a user take inventory of one or more components. For instance, after spinal surgery, a physician or other health care professional may use a reader to confirm that all of the set screws and anchoring members allocated for the procedure have been used and are positioned in a patient. This may also help with the detection and verification of lost screws in a patient's body.

<FIG> illustrates an example of a surgical site (SS) monitoring system <NUM> that may utilize example set screws <NUM> disclosed herein. In some embodiments, the SS monitoring system <NUM> may be a surgical site load monitoring system (at least those set screws <NUM> utilizing a strain gauge <NUM>) and/or an infection monitoring system (at least those set screws <NUM> utilizing a temperature sensor).

In one or more embodiments, the SS monitoring system <NUM> may include an array of set screws <NUM>, in which one or more of the set screws <NUM> have a have any type of MEMs sensor as previously disclosed. For the cases in which the SS monitoring system <NUM> includes an array of set screws <NUM> having various MEMs sensors, the received data from the one or more MEMs sensors of set screws <NUM> may be compared to one another to diagnose the quality of the surgical procedure, the integrity of the implant, and/or an infection at the surgical site.

<FIG> illustrate an embodiment of a digital set screw <NUM> having a lateral antenna design. Digital set screw <NUM> may include the same, similar, or substantially the same features and functionality as the other embodiments of this disclosure and the co-related applications. For example, features from those embodiments may be incorporated into digital set screw <NUM> and vice versa unless the context clearly indicates otherwise.

<FIG> illustrates a partial cut out perspective view of a digital set screw <NUM> having a break off portion <NUM> and a remaining set screw portion <NUM>. In various embodiments, digital set screw portion <NUM> may include a hermetically sealed cavity <NUM> housing an antenna <NUM>, microelectronics <NUM>, and sensors <NUM>, for example. Consistent with this disclosure and the incorporated disclosures, sensors <NUM> may be any type of sensor, e.g., strain gauges, temperature gauges, etc. Additionally, sensors <NUM> may be arranged in any pattern, e.g., single, centered, distributed into quadrants, various patterns, etc. Breakoff portion <NUM> may include a drive feature <NUM> taking the shape of a hexalobe aperture, for example. Other drive features having different shapes are also contemplated, for example hexagonal, polygonal, torx, square head, spline, etc. In various embodiments, breakoff portion <NUM> may be configured to shear off from set screw portion <NUM> at a break off location or fracture surface <NUM> at a predetermined torque ensuring that such internal stresses are suppressed and/or do not interfere with the hermetic seal and electronics components within cavity <NUM>, for example. In various embodiments, digital set screw <NUM> and breakoff portion may be compatible with the Solera Spinal Systems sold by Medtronic of Minneapolis Minnesota. In the disclosed embodiment, once breakoff portion <NUM> is broken off, the remaining set screw portion <NUM> may have a torx head or a nut style head taking any suitable shape such that the set screw portion <NUM> may be still be driven and/or rotated absent the breakoff portion <NUM>, e.g., a Torx <NUM>. For example, as shown in <FIG>, the breakoff portion <NUM> is removed and the remaining set screw portion <NUM> includes a torx head portion <NUM>.

In some embodiments, set screw portion <NUM> may include an over-molding <NUM> and a threaded portion <NUM>. In various embodiments, over-molding <NUM> may be above and/or on top of lower portion <NUM> and be designed to accommodate an internal cavity. In at least one embodiment, the over-molding <NUM> may protrude about <NUM> - <NUM>, above the uppermost thread of lower portion <NUM>, for example. In at least one embodiment, over molding <NUM> protrudes about <NUM> above lower portion <NUM>, for example. In some embodiments, lower portion <NUM> may be formed of a metallic component, e.g. titanium and titanium alloys and include an external thread pattern on outside circumferential surface thereof, for example. As seen best in <FIG>, an upper portion of the internal cavity <NUM> may be contained within over-molding <NUM> and a lower portion of the internal cavity <NUM> may be contained within lower portion <NUM> (as shown in <FIG>). In various embodiments, a ceramic mold <NUM> may be inlayed within and/or contoured to an interior of over-molding <NUM>. In various embodiments, ceramic mold <NUM> may be referred as a ceramic cap <NUM> and as explained in further detail below, there may be a thin cavity and/or gap space between the ceramic cap <NUM> and the over-molding <NUM>. In this embodiment, the gap space may help to suppress and/or prevent potentially damaging internal flexural and shear stresses from being applied to the sensitive electronics equipment and hermetic seal. In various embodiments, ceramic cap <NUM> may be formed of Zirconia 3Y-TZP and/or a Zirconia toughed alumina (ZTA), for example.

<FIG> illustrates a perspective view of a ferrite core <NUM> for use with digital set screw <NUM>. Ferrite core <NUM> includes a bar or strut <NUM> coupled to and/or integrally formed with side portions <NUM>. In at least one embodiment, the side portions <NUM> and strut <NUM> may be separately formed and assembled together. Side portions <NUM> may have an outermost curved surface generally conforming to and corresponding to a curvature of cavity <NUM>, for example. Additionally, ferrite core <NUM> includes uppermost surfaces <NUM> that are planar and/or substantially planar. In other embodiments, uppermost surfaces <NUM> may be arcuate and/or curved to closely follow the inner profile of the cavity and/or ceramic cap. In the embodiment of <FIG>, an open area or void space is formed between side portions <NUM> and strut <NUM>. As shown in <FIG>, the void space is used as a winding area for winding of a wire into a coil, e.g., a copper wire is wound around strut <NUM> between the internal side surfaces of side portions <NUM> thereby forming an assembled antenna <NUM>. In the disclosed embodiment, the windings may be considered to be oriented in a lateral direction with respect to a longitudinal axis of the digital set screw <NUM>, for example. In various embodiments, such copper windings may have a relatively consistent and thin diameter or copper windings may be ribbon like and relatively thin. Other materials than copper may also be used, for example silver, gold, stainless steel alloys and various combinations of conductive materials.

<FIG> illustrates a first side view of the antenna <NUM> of <FIG> and <FIG> illustrates a second side view of the antenna of <FIG>. In the illustrated embodiment, the windings <NUM> are flush with the upper surfaces <NUM> of ferrite core <NUM>. The inventors have discovered that, at least in some embodiments, an antenna <NUM> formed of a ferrite core <NUM> with windings <NUM> spooled around strut <NUM> to such a relative height that windings <NUM> are substantially flush with uppermost surfaces <NUM> is a highly advantageous design. For example, this antenna design is well suited to the size constraints and limitations of the relatively small cavity <NUM> while also still having relatively strong transmission abilities, a known issue with various digital set screw embodiments. An additional factor may be in an ability for a digital set screw to couple to a power unit and/or receive a wireless charge as a transmission from an external device. Various embodiments disclosed herein have been shown by experimental testing to have a greater transmission ability for receiving and sending as compared to other antenna designs, e.g., such as longitudinal coil designs.

<FIG> illustrates a cross section view of set screw <NUM>. This embodiment may include the same, similar, and/or substantially the same features as the embodiment of <FIG>. This embodiment may differ from the embodiment of <FIG> in that an overmold portion <NUM> separates a first cavity <NUM> and a second cavity <NUM>. The first cavity <NUM> may house the antenna, <NUM> while the second cavity <NUM> may house the sensor(s) <NUM>, for example. Additionally, in various embodiments, microelectronics <NUM> (not illustrated in <FIG>) may be disposed in either of (or both) the first cavity <NUM> and second cavity <NUM>. In the cross-section view, it is shown that the windings <NUM> are disposed above and below strut <NUM> and between side portions <NUM>. It is also shown that ferrite core <NUM>, in cross section, has a substantially U shape. Sensors <NUM> may be disposed on the uppermost internal surface <NUM> of cover <NUM>, for example on an opposite surface from the exposed lower most surface <NUM> of cover <NUM>. In at least some embodiments, cover <NUM> may be formed of a metallic material, e.g., titanium and titanium alloys and may be formed of the same material as the other components of the threaded body. In at least one embodiment, the threaded body of digital set screw <NUM> and cover <NUM> may be formed of Ti-6AL-4V, for example. In various embodiments, lower most surface <NUM> may comprise a dimple as shown in <FIG>. In various embodiments, a dimple of lower most surface <NUM> may directly contact a spinal implant, e.g., a spinal support rod and facilitate retaining the spinal implant in a particular position.

<FIG> shows a remaining portion <NUM> of a digital set screw <NUM> after a breakoff portion <NUM> has been removed. In the example embodiment, a head portion <NUM> of the remaining portion may be driven and/or rotated by driver, e.g., a torx T50 driver, a hexalobe driver, etc. In the example embodiment, a slit extends through the uppermost surface of head portion <NUM> and on opposing side surfaces which may be filled with overmold <NUM>. At least one advantage of the slit and overmold <NUM> may be a relative increase in the efficacy of the power and communications of the antenna <NUM> on account of the removal of metal in this area. An additional advantage of the configuration shown in <FIG>, may be that sharp edges associated with a breakoff location are reduced and/or eliminated. Additionally, the overmold <NUM> may be disposed between and/or offset from drive edges 408A to prevent drive stresses from cracking and/or adversely affecting overmold <NUM>, for example. Furthermore, consistent with the disclosure herein, it shall be understood that <FIG> may also represent a digital set screw <NUM> having a lower profile which did not originally include a breakoff portion <NUM>, for example.

<FIG> illustrates a cross section drawing of another digital set screw <NUM> with an overmold portion <NUM> removed for ease of understanding. This embodiment may include the same, similar, and/or substantially the same features and functionality as the embodiment of <FIG> and the embodiment of <FIG>. Accordingly, duplicative description will be omitted. This embodiment may differ in that the antenna <NUM> and ceramic mold <NUM> are supported on a bellows <NUM>, for example. In this embodiment, bellows <NUM> may be flexible and serve a purpose of mechanically isolating various at-risk components from internal forces that may be transmit through the digital set screw <NUM> upon driving it, for example ceramic mold <NUM>. In this embodiment, bellows <NUM> facilitates the creation and maintenance of a hermetic seal and preservation of the integrity of antenna <NUM> and other electronic components <NUM> within the hermetic seal, for example.

In various embodiments, bellows <NUM> may be formed of a relatively thin metallic material on the order of about <NUM> to about <NUM>, and in other embodiments bellows <NUM> may be about <NUM> thick. In the example embodiment, bellows <NUM> may have a shape resembling an accordion and be compressible and extendable in a longitudinal direction of digital set screw <NUM> while also allowing for flexural deflection in a lateral direction. However, in other embodiments it shall be understood that bellows <NUM> may have a shape resembling a leaf spring, a coil spring, and other similar structures. As illustrated, bellows <NUM> includes an upper support surface <NUM> and an optional sidewall surface immediately adjacent upper support surface <NUM> forming a channel with which ceramic mold <NUM> may rest. The ceramic mold may be securely coupled to bellows <NUM> by a braze joint <NUM> or by any type of suitable weld or adhesive, for example aspot weld, laser weld, sonic weld, and/or an epoxy. Additionally, bellows <NUM> may be securely coupled to an interior sidewall 409A of digital set screw <NUM> at weld location <NUM>. In this way, bellows <NUM> is securely coupled to the interior cavity <NUM> of digital set screw <NUM> at a lower region only. However, in other embodiments bellows <NUM> may additionally or alternatively be secured to the interior sidewall 409A defining interior cavity <NUM> at an intermediate region and/or an upper region, for example. In another alternate embodiment, the bellows <NUM> may additionally or alternatively be secured to the cover <NUM>. Furthermore, bellows <NUM> may have a size and shape such that a gap space <NUM> is formed between bellows <NUM> and interior sidewall 409A of digital set screw <NUM>. Gap space <NUM> may be any size such that it allows sufficient room for bellows <NUM> to deflect under the expected loads digital set screw <NUM> may sustain in ordinary use. In some embodiments, the side walls 409A may also deflect and the gap may additionally serve the functional benefit of preventing the bellows <NUM> and/or ceramic from coming into contact with the side walls 409A (at least at regions where the bellows <NUM> and/or ceramic is not coupled to the wisewalls 409A). Consistent with the disclosure herein, and as an example configuration, bellows <NUM> is fully and/or substantially disposed beneath the windings <NUM> and therefore will not create any significant interference with the performance of antenna <NUM>.

<FIG> illustrates a cross-section drawing of another digital set screw <NUM> with an overmold portion <NUM> removed for ease of understanding. This embodiment may include the same, similar, and/or substantially the same features and functionality as the embodiment of <FIG>, <FIG>, and <FIG> for example. Accordingly, duplicative description will be omitted. This embodiment may differ in that the antenna <NUM> and various other electronics components <NUM> are disposed within a cylindrical structure <NUM>, for example. Cylindrical structure <NUM> may resemble a can having a closed upper surface, closed sidewall surfaces, and an open lower surface facing cover <NUM>, for example. In various embodiments, cylindrical structure <NUM> be a relatively thin-walled structure on the order of about <NUM> to about <NUM>, and in some embodiments about <NUM> to about <NUM> depending on manufacturing tolerances. Cylindrical structure <NUM> may be formed of any metallic material or alloy, for example Ti-<NUM> / Ti-<NUM> and can serve at least one purpose of forming a hermetic enclosure surrounding antenna <NUM> and various other electronics components <NUM>, for example. In this embodiment, the ferrite core <NUM> of antenna <NUM> may be relatively larger than the embodiment shown in <FIG> and <FIG> and be formed to have a cylindrical shape approximating the available space defined by cylindrical structure <NUM>, for example. Similar to the embodiment shown in <FIG>, the cylindrical structure may be disposed within cavity <NUM> and welded to an interior sidewall 409A of digital set screw <NUM>.

<FIG> illustrates a perspective view of a digital set screw <NUM>. This embodiment illustrates a remaining portion <NUM> of a digital set screw <NUM> after a breakoff portion <NUM> has been removed. In the example embodiment, a head portion <NUM> of the remaining portion <NUM> may resemble a spline screw and may be driven and/or rotated by any suitable driver having a corresponding shape. In the example embodiment, a slit and/or opening extends through the body portion of digital set screw <NUM> in the uppermost surface of head portion <NUM> and on opposing side surfaces. The slit may separate the uppermost surface of head portion <NUM> into two parts and thereby prevent an eddy current from forming and interfering with the performance of the antenna and/or other electronics. In <FIG>, the slit is shown as being filled with overmold <NUM>, which may be an insulator formed of a thermoplastic. At least one advantage of the slit and overmold may be a relative increase in the performance of the antenna <NUM> on account of the removal of metal in this area. Another advantage of the configuration shown in <FIG>, may be that sharp edges associated with a breakoff location are reduced and/or eliminated. In some embodiments, and as shown in <FIG>, overmold portion <NUM> may also correspond spatially to the location of antenna <NUM> and thereby reduce interference associated with metallic body of digital set screw <NUM>. Additionally, in various spline drive embodiments, drive edges <NUM> may be spaced around the outside circumferential sides of digital set screw <NUM> to assist with the distribution of localized forces to portion <NUM> to prevent drive stresses from cracking and/or adversely affecting overmold <NUM>, for example. In one example, three drive edges <NUM> are disposed on each side of the slit and overmold <NUM> (total of six drive edges <NUM>). In various embodiments, the drive edges <NUM> may be symmetrically spaced around the diameter of head portion <NUM> and or unevenly spaced around the diameter of head portion <NUM>. In at least one embodiment, a first group of three drive edges are clustered on a first side of slit and overmold <NUM> and a second group of three drive edges are clustered on a second side of slit and overmold <NUM> in a non-symmetrical spacing such that drive edges are farther from the relatively weaker area of the set screw <NUM> corresponding to the slit and overmold <NUM>. In various embodiments, this offset nature may improve performance and viability of the digital set screw <NUM> because torque may be applied in an efficient and distributed manner that prevents and/or suppresses the possibility of digital set screw <NUM> buckling at high loads along the portion of set screw <NUM> corresponding to slit and overmold <NUM>. In at least one embodiment, experimental testing has shown that the embodiment of <FIG> is capable of enduring forces in excess of about <NUM> without buckling. Furthermore, consistent with the disclosure herein, it shall be understood that <FIG> may also represent a digital set screw <NUM> having a lower profile which did not originally include a breakoff portion <NUM>, for example.

Further non-claimed embodiments of the invention are as follows:.

There is provided a load sensing assembly (e.g., a load sensing system), the load sensing assembly (e.g., load sensing system) comprising: a plurality of set screws, each set screw comprising: an upper surface, an outside thread pattern disposed on a circumferential side surface, a bottom surface, and an internal cavity disposed between the bottom surface, the circumferential side surface, and the upper surface; an antenna comprising a ferrite core and a plurality of windings; and at least one sensor comprising an integrated circuit in communication with the antenna, the sensor configured to detect an external force applied to the bottom surface, wherein the sensor and integrated circuit are positioned within the internal cavity, and wherein the antenna is configured to transmit information received from the at least one sensor to an external device.

Further, there is provided the load sensing assembly of the first further embodiment, wherein each ferrite core comprises a strut disposed between opposite side portions and each of the plurality of windings are wound around the strut.

Claim 1:
A load sensing assembly for a spinal implant, the load sensing assembly comprising:
a set screw (<NUM>) comprising an upper surface, an outside thread pattern (<NUM>) disposed on a circumferential side surface, a bottom surface, and an internal cavity (<NUM>) disposed between the bottom surface, the circumferential side surface, and the upper surface;
an antenna (<NUM>); and
at least one sensor (<NUM>) comprising an integrated circuit in communication with the antenna (<NUM>), the sensor (<NUM>) configured to detect an external force applied to the bottom surface,
wherein the sensor (<NUM>) and the integrated circuit are positioned within the internal cavity (<NUM>), and
wherein the antenna (<NUM>) is configured to transmit information received from the at least one sensor (<NUM>) to an external device,
characterized in that:
the antenna (<NUM>) comprises a ferrite core (<NUM>) and a plurality of windings (<NUM>);
the ferrite core (<NUM>) comprises a strut (<NUM>) disposed between opposite side portions (<NUM>); and
the plurality of windings (<NUM>) are wound around the strut (<NUM>), and
an uppermost surface of the plurality of windings (<NUM>) is substantially flush with an uppermost elevation (<NUM>) of the ferrite core (<NUM>).