Patent Description:
Robotic systems are being increasingly implemented in surgical applications. One such example involves a surgical robot used in dental surgery. Such robots are often associated with a guidance system used to guide the surgical instrument implemented by the surgical robot. The guidance system may also be configured to be involved in the surgical pre-planning process, whether by being involved in gathering and/or analyzing patient data, and planning the surgical procedure, or by relying upon pre-planning data to guide the surgical instrument to conduct the surgical procedure.

In particular, surgical procedures, some surgical robotic systems rely upon a fixed reference point associated with the patient's body for guiding the surgical robot. That is, some such surgical robotic systems define a frame of reference with respect to the patient's body so as to account or otherwise compensate for movements or motion of the patient during the procedure, whether during pre-planning or during the actual surgical procedure itself. This reference point must also be repeatable such that multiple engagements/disengagements (i.e., periods between pre-planning and the actual surgical procedure) do not change the frame of reference implemented by the surgical robot or the guidance system associated therewith.

In particular instances, the reference point (or the connection between the guidance system and the patient to define that reference point) implemented by the guidance system for the surgical robot may be accomplished through, for example, an optical modality, a mechanical modality, an acoustic modality, or other suitable and appropriate tracking/guiding modality, or combination thereof. In some modalities, particularly used in dental surgery applications, one mechanical modality for forming the reference point (i.e., a "fiducial marker") may be accomplished, for example, by attaching / securing a rigid element to the head / teeth of the patient. Such a rigid element, in some instances, may be referred to as and may comprise a splint (see, e.g., prior art in <FIG>, <FIG>). Such a splint may generally include, for instance, a retainer portion that grips one or more of the teeth (i.e., by way of an adhesive substance, such as an acrylic material applied between the retainer portion and the teeth), a mounting portion (i.e., mounting arm) that connects the retainer portion to a separate kinematic mount, and the kinematic mount, itself, which may comprise an attachment point for a tracking portion associated with the guidance system for the surgical robot (i.e., wherein, for instance, reflective markers may be mounted to the attachment point for optical tracking of the fiducial marker, or the attachment point may include a securing site for forming a mechanical connection therewith for mechanical tracking of the fiducial marker, or the attachment point may otherwise be configured to receive an appropriate element associated with any other suitable tracking arrangement for the fiducial marker).

In such instances, it may be preferable for the retainer portion to be as rigid as possible (i.e., the structure of the retainer itself, as well as the fixation thereof to the teeth of the patient) throughout the surgical procedure. However, it may also be preferable for the retainer portion to be readily removable when the surgical procedure is complete. In some instances, it may be preferable for the splint to be reproducibly removed and replaced, for example, between the pre-planning procedure (i.e., a CT scan) which may occur on one day (when the splint must be in place so the fiducial marker(s) associated therewith are captured in the scan), and the surgical procedure may occur on another day (wherein the surgical procedure requires the splint to be in place for tracking / guiding the surgical procedure). In other instances, it may be preferable that a single splint configuration be usable or adaptable across a wide population of patients, for example, as a universal fit device. Further, it may be desirable to have a minimum of separate components of the splint, or if separate components are included, that such separate components are integrated into or are firmly and securely affixed as part of the overall splint assembly.

Prior art splint devices as shown, for example, in <FIG>, <FIG>, also require a careful balance of the adhesive material (i.e., dental acrylic) to be applied in order to be effective in rigidly mounting the retainer portion to the teeth of the patient. For instance, if too little of the adhesive material is applied in the retainer portion, the splint device may be too easily separated from the teeth, since the amount of the adhesive material may not be sufficient to bond the retainer portion to the teeth to sufficiently resist the forces applied thereto during the surgical procedure. However, if too much of the adhesive material is applied to the retainer portion, the excess adhesive material may flow into the tooth undercuts (i.e., the portion of the tooth where the tooth narrows toward the gum-line and/or the spaces between teeth), the retainer portion will not be readily removable at the end of the surgical procedure, without, for instance, drilling into the solidified adhesive material to remove the retainer portion from the tooth/teeth. In such instances, the retainer portion will likely not be re-usable for the particular patient, and if further procedures are required, a new retainer portion, including a new mounting portion for the fiducial marker and/or tracking marker, may also be required.

As such, there exists a need for a splint device for forming a fiducial marker for the guidance system of a surgical robot used, for example, in dental surgery which addresses these and other limitations of prior art devices.

<CIT> discloses a fiducial marker holder for e.g. image guided surgery, including a marker attachment device removably attached to arms for accommodating marker attachment points for receiving fiducial markers in different orientations.

<CIT> discloses a method of implementing a splint device, and an associated splint device for a guidance system of a surgical robot. A splint body includes first and second stabilizing portions extending from opposed lateral sides of a medial portion, and defines a U channel. The medial portion, or the medial portion and one of the stabilizing portions, defines a bridge portion extending along the U channel. A partition member, received by the bridge portion, extends into and longitudinally along the U channel. An adhesive material is engaged with the splint body, within the U channel. The U channel is engaged about a tooth or jaw of a patient, and urged toward the tooth or jaw, such that the partition member engages the tooth or jaw and separates the adhesive material into a first portion engaged with the first stabilizing portion and a second portion engaged with the second stabilizing portion.

<CIT> discloses a cannulated dental implant system for implanting a dental implant in bone tissue including a guide splint having at least one guide sleeve defining a guide channel. The system also includes a guide pin with a bone penetrating end portion. The guide pin is extendable through the guide channel and drivable into bone tissue. Further, the system includes a first drill bit with a first outer diameter and an axial channel sized to receive the guide pin. The first drill bit is rotatable about the guide pin to drill a hole into the bone tissue. The hole has a diameter corresponding with the first outer diameter. The system includes a second drill bit with a second outer diameter that is greater than the first outer diameter. The second drill bit further includes an axial channel sized to receive the guide pin. Moreover, the second drill bit is rotatable about the guide pin to enlarge the hole in the bone tissue to correspond with the second outer diameter. Additionally, the system includes a dental implant securable within the enlarged hole.

<CIT> discloses another splint device for forming a fiducial marker for a surgical robot guidance system.

The invention is defined by appended independent claims <NUM> and <NUM>.

The above and other needs are met by aspects of the present disclosure which, in one particular aspect, provides a splint device for guided robotic surgery. Such a device comprising an elongate first splint portion having first and second longitudinal ends, and a first interface edge extending therebetween. An elongate second splint portion has first and second longitudinal ends, and a second interface edge extending therebetween. The second splint portion co-extends with the first splint portion, with the second interface edge arranged as a complement to the first interface edge. An alignment provision includes a first alignment element engaged with the first splint portion and a second alignment element engaged with the second splint portion, the first and second alignment elements being arranged to interact with each other such that a substantially consistent gap is defined between the first and second interface edges, from the respective first ends to the respective second ends of the first and second splint portions, as the first and second splint portions are advanced toward each other. A threaded member is engaged between the first and second splint portions and is arranged to advance the first and second interface edges toward each other in response to advancement of the threaded member relative to the first and second splint portions. A tracking portion is engaged with the first splint portion or the second splint portion, and extends outwardly therefrom, wherein the tracking portion has a kinematic mount engaged therewith.

Another aspect of the present disclosure provides a method of applying a splint device for facilitating guided robotic surgery. Such a method comprises engaging an elongate first splint portion with a co-extending elongate second splint portion, wherein each splint portion has first and second longitudinal ends and an interface edge extending between the first and second ends, wherein the interface edges are arranged as a complement to each other, such that a first alignment element engaged with the first splint portion and a second alignment element engaged with the second splint portion interact with each other, wherein the first or second splint portion has a tracking portion engaged therewith and extending outwardly therefrom, and wherein the tracking portion has a kinematic mount engaged therewith. A threaded member is engaged between the first and second splint portions, with the threaded member being arranged to advance the first and second interface edges toward each other, as guided by the interacting first and second alignment elements, in response to advancement of the threaded member relative to the first and second splint portions such that a substantially consistent gap is defined between the first and second interface edges, from the respective first ends to the respective second ends of the first and second splint portions, as the first and second splint portions are advanced toward each other.

These and other features, aspects, and advantages of the present disclosure will be apparent from a reading of the following detailed description together with the accompanying drawings, which are briefly described below. The present disclosure includes any combination of two, three, four, or more features or elements set forth in this disclosure, regardless of whether such features or elements are expressly combined or otherwise recited in a specific embodiment description herein. This disclosure is intended to be read holistically such that any separable features or elements of the disclosure, in any of its aspects and embodiments, should be viewed as intended, namely to be combinable, unless the context of the disclosure clearly dictates otherwise.

It will be appreciated that the summary herein is provided merely for purposes of summarizing some example aspects so as to provide a basic understanding of the disclosure. As such, it will be appreciated that the above described example aspects are merely examples and should not be construed to narrow the scope of the disclosure in any way. It will be appreciated that the scope of the disclosure encompasses many potential aspects, some of which will be further described below, in addition to those herein summarized. Further, other aspects and advantages of such aspects disclosed herein will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described aspects.

The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all aspects of the disclosure are shown. Indeed, the disclosure may be embodied in many different forms and should not be construed as limited to the aspects set forth herein; rather, these aspects are provided so that this disclosure will satisfy applicable legal requirements.

Particular aspects of the present disclosure as shown, for example, in <FIG>, provide a splint device <NUM> for use with a guidance system of a surgical robot, for instance, in dental surgery. One skilled in the art, however, will appreciate that the concept of the splint device disclosed herein as forming a fiducial marker and/or a tracking marker, or otherwise a frame of reference for a surgical robotic system may find applicability to other surgical processes not involving dental surgery, such as, for example, orthopedic surgery, ENT surgery, and neurosurgery. As such, the aspects of the disclosure presented herein are merely examples of the applicability of the disclosed concepts and are not intended to be limiting in any manner.

Such a splint device <NUM> implemented in conjunction with a guided surgical robot comprises an elongate first splint portion <NUM> (e.g., a lingual portion) having first and second longitudinal ends 200A, 200B, having a first interface edge <NUM> extending between the first and second ends 200A, 200B, and in some instances defining longitudinally spaced-apart relief holes <NUM> (see, e.g., <FIG> and <FIG>). An elongate second splint portion <NUM> (e.g., a buccal portion) has first and second longitudinal ends 400A, 400B, has a second interface edge <NUM> extending between the first and second edges 400A, 400B, and in some instances defines longitudinally spaced-apart relief holes <NUM> (see, e.g., <FIG> and <FIG>). The second splint portion <NUM> generally co-extends with the first splint portion <NUM>, wherein the second interface edge <NUM> is arranged as a complement to the first interface edge <NUM>, as shown, for example, in <FIG> and <FIG>.

As shown, for example, in <FIG> and <FIG>, the splint device <NUM> includes at least one alignment provision 800A or 800B, wherein each alignment provision includes a first alignment element 825A or 825B engaged with the first splint portion <NUM> and a second alignment element 850A or 850B engaged with the second splint portion <NUM>. In particular aspects, the splint device <NUM> includes at least two alignment provisions 800A, 800B, wherein one of the alignment provisions 800A includes a first alignment element 825A engaged with the first splint portion <NUM> and a second alignment element 850A engaged with the second splint portion <NUM>, and the other of the alignment provisions 800B includes a first alignment element 825B engaged with the first splint portion <NUM> and a second alignment element 850B engaged with the second splint portion <NUM>.

In some aspects, the corresponding first and second alignment elements 825A, 850A and/or 825B, 850B are configured as complements to each other. For example, as shown in <FIG>, the first alignment element 825A and/or 825B can be a frustoconical receptacle defined by the first splint portion <NUM>, wherein the frustoconical receptacle has a major diameter 825A1 and/or 825B1 and a minor diameter 825A2 and/or 825B2, with the major diameter 825A1 and/or 825B <NUM> of the frustoconical receptacle being directed toward the second splint portion <NUM>. Accordingly, the second alignment element 850A and/or 850B is a frustoconical protrusion extending from the second splint portion <NUM>, wherein the frustoconical protrusion has a major diameter 850A1 and/or 850B1 and a minor diameter 850A2 and/or 850B2, with the minor diameter 850A2 and/or 850B2 of the frustoconical protrusion being directed toward the first splint portion <NUM>. One skilled in the art will appreciate, however, that the alignment provision(s) may be configured and arranged in many different manners instead of or in addition to the configurations/arrangements disclosed herein, and that the examples disclosed herein are not limiting in this regard in any manner.

Generally, the first alignment element 825A and/or 825B and second alignment element 850A and/or 850B are arranged to interact with each other (e.g., the alignment protrusion being received by the alignment receptacle) such that a substantially consistent gap <NUM> (see, e.g., <FIG>) is defined between the first and second interface edges <NUM>, <NUM>, from the respective first ends 200A, 400A to the respective second ends 200B, 400B of the first and second splint portions <NUM>, <NUM>, as the first and second splint portions <NUM>, <NUM> are advanced toward each other.

A threaded member <NUM> is engaged between the first and second splint portions <NUM>, <NUM> and is arranged to advance the first and second interface edges <NUM>, <NUM> toward each other in response to advancement of the threaded member <NUM> relative to the first and second splint portions <NUM>, <NUM>. For example, the second splint portion <NUM> defines an unthreaded bore <NUM> arranged to allow the threaded member <NUM> to pass therethrough, while the first splint portion <NUM> defines a threaded bore <NUM> arranged opposite the unthreaded bore <NUM> and configured to form a threaded engagement with the threaded member <NUM>. Accordingly, advancing the threaded member <NUM> through the unthreaded bore <NUM> and into engagement with the threaded bore <NUM>, while the alignment provisions 800A, 800B are engaged, forms a mechanism for advancing /retracting the first and second splint portions <NUM>, <NUM> with respect to each other upon advancement or retraction of the threaded member <NUM> with respect to the threaded bore <NUM>, while maintaining the substantially consistent gap <NUM> between the first and second interface edges <NUM>, <NUM>. As shown, for example, in <FIG>, in instances where the splint device <NUM> includes a first and a second alignment provision 800A, 800B, the threaded member <NUM> engaged between the first and second splint portions <NUM>, <NUM>, is disposed between the first and second alignment provisions 800A, 800B.

A tracking portion <NUM> is engaged with the first splint portion <NUM> or the second splint portion <NUM>, and extends outwardly therefrom. In <FIG>, the tracking portion <NUM> is engaged with the second (buccal) splint portion <NUM>. More particularly, in some aspects, the tracking portion <NUM> extends from the first end 200A, 400A or the second end 200B, 400B of the first or second splint portion <NUM>, <NUM>. The tracking portion <NUM> has a kinematic mount <NUM> engaged therewith. In some aspects, the kinematic mount <NUM> is integrally formed with the tracking portion <NUM>.

The kinematic mount <NUM> (see, e.g., <FIG>), in some instances, defines a central locating receptacle <NUM> surrounded by three or more angularly spaced-apart protrusions <NUM>. Such a kinematic mount <NUM> is generally configured to receive a complementarily-configured mount (not shown) including or engaged with a tracking provision. The tracking provision can include, for example, a physically connected tracking provision such as a tracking arm connected to the surgical robot. In other instances, the tracking provision can include, for example, a non-physically connected tracking provision such as an optical tracking device, a magnetic tracking device, a wireless or WiFi tracking device, an electromagnetic tracking device, an inductive tracking device, or any other form of tracking device that does not require a physical connection between the tracking provision affixed to the kinematic mount <NUM> and the surgical robot. In either instance, the integration of the kinematic mount <NUM> into the tracking portion <NUM> provides for repeatable engagement with the tracking provision, with interchangeable engagement between different types of tracking provisions. The integration of the kinematic mount <NUM> can further be accomplished, for example, through molding, machining, and or 3D printing.

In other instances, a separability provision <NUM> (see, e.g., <FIG>) extends across the first and second splint portions <NUM>, <NUM>, between the first or second alignment provision 800A, 800B and the first longitudinal ends 200A, 400A or second longitudinal ends 200B, 400B of the first and second splint portions <NUM>, <NUM>, wherein the separability provision <NUM> is arranged to be severable so as to facilitate adjustability of a length of the first and second splint portions <NUM>, <NUM>. The adjustability of the length of the splint device <NUM> via the separability provision <NUM> can facilitate, for example, the implementation of the splint device <NUM> to a variety of different size applications (e.g., adult teeth or children's teeth). The separability provision <NUM>, in some aspects, comprises a reduced section thickness extending across the first and second splint portions <NUM>, <NUM>. In other aspects, multiple severability provisions <NUM> can be provided along the first and second splint portions <NUM>, <NUM> to provide for multiple adjustability of the length of the splint device <NUM>.

In other instances, a tool calibration provision <NUM> (see, e.g., <FIG>) is engaged with the first splint portion <NUM>, the second splint portion <NUM>, or the tracking portion <NUM>, wherein the tool calibration provision <NUM> is disposed in a predetermined disposition relative to the kinematic mount <NUM>. The tool calibration provision <NUM> may be configured, for example, as a receptacle or other suitable surface feature for receiving the end effector (e.g., a tip of a drill bit) of a surgical instrument affixed to the surgical robot. The tool calibration provision <NUM>, in some instances, is formed integrally with the particular component of the splint device <NUM> or, in other instances, can be a separate and discrete element (e.g., a durable element such as a metal element, a ceramic element, or other suitable element). Since the tool calibration provision <NUM> is in a known disposition relative to the kinematic mount <NUM>, the tool calibration provision <NUM>, upon interaction with the end effector of the surgical robot, provides a confirmation or calibration that the end effector is accurately tracked in relation to the surgical robot for conducting a procedure. In some instances, the tool calibration provision <NUM> is radiopaque such that the disposition thereof with respect to the kinematic mount <NUM> can be determined and/or confirmed through imaging analysis.

In yet other instances, a fiducial marker element <NUM> (see, e.g., <FIG>) is received by a depression (not shown) defined by an outer surface (e.g., the outer surface of the second splint portion <NUM>) of the splint device <NUM> or the tracking portion <NUM>, wherein the fiducial marker element <NUM> is received in a predetermined disposition relative to the kinematic mount <NUM>. In particular aspects, the outer surface of the splint device <NUM> defines a plurality of depressions arranged to receive a corresponding plurality of fiducial marker elements <NUM>. For example, in some aspects, the fiducial marker element <NUM> is spherical and the depression is hemispherical or an elongate concave channel arranged to receive the spherical fiducial marker element <NUM>. Once secured with the respective depression, whether through an interference fit (e.g., a press fit), by overmolding, or with an adhesive material (e.g., epoxy) disposed with the depression, the fiducial marker element(s) <NUM> are essentially embedded within the splint device <NUM>. Moreover, in some aspects, the depressions are oriented such that the adhesive material (e.g., epoxy) is retained, such as by gravity, at the location in the depression at which the fiducial marker element <NUM> is secured/embedded. Since the fiducial marker element(s) <NUM> are radiopaque in some aspects, the fiducial marker element(s) <NUM> can be detected through imaging analysis (e.g., a CT scan). Accordingly, in particular instances, the fiducial marker element(s) <NUM> are radiopaque and can be differentiated from the splint device <NUM> (e.g., formed of a plastic/polymeric material). Since the fiducial marker element(s) <NUM> are all embedded with the splint device <NUM>, the field of view of the imaging analysis (e.g., the CT scan) can be reduced.

In some aspects, the first and second splint portions <NUM>, <NUM> interact to collectively form an elongate channel <NUM> (see, e.g., <FIG>) having an inner surface defining a concavity (e.g., a "U" channel in cross-section). In such instances, the elongate channel <NUM> is arranged and configured, for example, to receive a bite registration material or a dental impression material <NUM> therein, where such a material can comprise, for example, a vinyl polysiloxane material. One skilled in the art will appreciate, however, that such an example material is not limiting in any manner and that many other materials can be suitable for conforming to, for example, a patient's tooth structure without adhering to the tooth surface itself. Accordingly, once the impression material <NUM> is deposited within the elongate channel <NUM> defined by the splint device <NUM> as shown, for example, in <FIG>, the splint device <NUM> is then applied to an object such as, for example, the teeth or jaw of a patient undergoing a dental surgical procedure. One skilled in the art will appreciate, however, that the application of the splint device <NUM> and the subsequent procedure does not necessarily involve a human patient. For example, the splint could be applied to a dummy patient for facilitating training of a user, for demonstration purposes, or otherwise for verification of the apparatus/system itself.

As previously disclosed, once the splint device <NUM> is applied to the object, the threaded member <NUM> can be advanced in the threaded engagement with the threaded bore <NUM> defined by the first splint portion <NUM> so as to advance the first splint portion <NUM> toward the second splint portion <NUM> and secure the subject therebetween, while maintaining the substantially consistent gap <NUM> between the first and second interface edges <NUM>, <NUM> as shown, for example, in <FIG>. As shown in <FIG>, in some instances, addition impression material <NUM> may be applied in the gap <NUM> between the first and second interface edges <NUM>, <NUM> as the first and second splint portions are advanced toward each other by way of advancement of the threaded member <NUM>.

As the first and second splint portion <NUM>, <NUM> are advanced toward the object (see, e.g., <FIG>), any excess impression material <NUM> within the elongate channel <NUM> is relieved by flow of the impression material out of the elongate channel through the respective relief holes <NUM>, <NUM> toward the outer surface of the first and/or second splint portions <NUM>, <NUM> (see, e.g., <FIG> and <FIG>). In this manner, the splint device <NUM> is secured to the object, such as the teeth / jaw of a patient. When the impression material <NUM> sets, the splint device <NUM> thus becomes securely fastened to the object (e.g., teeth or jaw of a patient), without the impression material significantly adhering to the surface of the teeth / jaws as compared to an adhesive material such as acrylic. The set / cured impression material <NUM> is sufficiently rigid so as to provide a secure and rigid mount of the splint device <NUM> to the teeth / jaw of the patient in conjunction with the pressure applied thereto by the first and second splint portions <NUM>, <NUM> urged toward each other by the threaded member <NUM>. In some instances, as shown for example in <FIG>, the first and second splint portions <NUM>, <NUM> can be advanced toward each other by the threaded member <NUM> until the first and second interface edges <NUM>, <NUM> contact each other to sufficiently secure the splint device <NUM> to the teeth / jaw of the patient. As shown, for example, in <FIG>, removal of the splint device <NUM> thus becomes a matter of retracting the threaded member <NUM> from the threaded bore <NUM> of the first splint portion <NUM>, which releases the pressure on the impression material <NUM> exerted by the first and second splint portions <NUM>, <NUM> and allows the splint device <NUM> to be removed from the object (since the impression material would also not adhere to the splint device <NUM>).

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these disclosed embodiments pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that embodiments of the invention are not to be limited to the specific embodiments disclosed. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the disclosure. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated within the scope of the disclosure. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

It should be understood that although the terms first, second, etc. may be used herein to describe various steps or calculations, these steps or calculations should not be limited by these terms. These terms are only used to distinguish one operation or calculation from another. For example, a first calculation may be termed a second calculation, and, similarly, a second step may be termed a first step, without departing from the scope of this disclosure. As used herein, the term "and/or" and the "/" symbol includes any and all combinations of one or more of the associated listed items.

Claim 1:
A dental splint device (<NUM>) for guided robotic surgery, said device comprising:
an elongate first splint portion (<NUM>) having first and second longitudinal ends (200A, 200B), and a first interface edge (<NUM>) extending therebetween;
an elongate second splint portion (<NUM>) having first and second longitudinal ends (400A, 400B), and a second interface edge (<NUM>) extending therebetween, the second splint portion (<NUM>) co-extending with the first splint portion (<NUM>) with the second interface edge (<NUM>) arranged as a complement to the first interface edge (<NUM>);
a threaded member (<NUM>) engaged between the first and second splint portions (<NUM>, <NUM>) and arranged to advance the first and second interface edges (<NUM>, <NUM>) toward each other in response to advancement of the threaded member (<NUM>) relative to the first and second splint portions (<NUM>, <NUM>);
a tracking portion (<NUM>) engaged with the first splint portion (<NUM>) or the second splint portion (<NUM>) and extending outwardly therefrom, the tracking portion (<NUM>) having a kinematic mount (<NUM>) engaged therewith; and
an alignment provision (800A, 800B) including a first alignment element (825A, 825B) engaged with the first splint portion (<NUM>) and a second alignment element (850A, 850B) engaged with the second splint portion (<NUM>), the first and second alignment elements (825A, 850A, 825B, 850B) being arranged to interact with each other to align the first and second splint portions (<NUM>, <NUM>) to provide a substantially consistent gap (<NUM>) defined between the first and second interface edges (<NUM>, <NUM>), from the respective first ends (200A, 400A) to the respective second ends (200B, 400B) of the first and second splint portions (<NUM>, <NUM>), as the first and second splint portions (<NUM>, <NUM>) are advanced toward each other by advancement of the threaded member (<NUM>).