Patent Publication Number: US-2020289271-A1

Title: Modular mandibular prosthesis

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. For example, this application claims the benefit of priority of U.S. Provisional Application No. 62/816,955, filed Mar. 12, 2019, and titled “Nedrud Modular Prosthesis,” the entirety of which is incorporated by reference herein for all purposes and forms a part of this specification. 
    
    
     BACKGROUND 
     Field 
     The technology relates to prosthetics, in particular to mandibular prosthetics. 
     Description of the Related Art 
     A mandibulectomy or segmental mandibulectomy is a medical procedure involving removal of part of the jaw bone, also known as the mandible. This may be done when, for example, benign or malignant pathology, trauma, among others is involved with or close to involving the mandible. The defective portion is then reconstructed and replaced with a prosthetic, autograft, allograft, synthetic graft mandible or portion thereof. Existing solutions to replacing the defective portion include replacement with metal plates and/or bone from another area of the body. For example the surgeon can use bone from the patient with or without its own blood supply, or simply bridge the bony gap with a titanium plate and screws. However, there are drawbacks to using bone, including morbidity of harvesting tissue from another site in the body, the time that it takes to perform the surgery, and its associated costs. Further, using a titanium plate and screws alone, without further reconstruction, compromises establishment of a desired cosmetic form, which is a major tenet of reconstruction. 
     Another approach to reconstructing a mandibulectomy includes custom made Virtual Surgically Planned (VSP) titanium mandibular reconstruction, with or without grafting. However, great time and expense is required to image the mandible and 3D print the prosthesis. The major drawback of this alternative is the time and expense required. 
     There is therefore a need for improvements to existing solutions to segmental mandibulectomies. 
     SUMMARY 
     The embodiments disclosed herein each have several aspects, no single one of which is solely responsible for the disclosure&#39;s desirable attributes. Without limiting the scope of this disclosure, its more prominent features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled “Detailed Description of the Preferred Embodiments,” one will understand how the features of the embodiments described herein provide advantages over existing approaches to mandibular prostheses. 
     The devices and methods described herein may be used in patients with segmental mandibular defects (e.g. missing segments of the lower jaw). The development includes a modular mandibular (lower jaw) prosthetic that can be easily adapted to any shape and location of the mandible. A prosthesis or portion thereof may be custom built using modular links attached together to a desired length and configuration. A plurality of connector links may be connected together in a desired size and orientation. Each link has a body with engagement structures, which may be on one or both of first and second ends of the body. The engagement structure on the first end of a first link is received by the engagement structure on the second end of a second link. The connected links can be in a locked and unlocked state. An expansion or compression member engages the connected link to cause the prosthesis to be in the locked state. An end attachment may be used on ends of outermost connected links to attach the prosthesis to a patient&#39;s mandible. 
     The prosthesis can be used as either a temporary place holder prior to definitive reconstruction, or as a permanent solution with a future possibility of definitive reconstruction with dental implants. In a select group of patients needing palliative resection, it can serve as the final reconstruction, thus relieving the patient of the morbidity of reconstruction with autogenous methods (i.e., using the patient&#39;s own tissues). The “building block” approach to mandibular prosthetics described herein may also be used for other prosthetics in other parts of the body. 
     In one aspect, a modular mandibular prosthetic for replacing at least a portion of a patient&#39;s mandible is described. The prosthetic comprises at least a first connector link and a second connector link, and an expansion or compression member. Both of the first and second connector links form at least a portion of the modular mandibular prosthetic. The modular mandibular prosthetic has an unlocked state and a locked state. Each of the first and second connector links has a body, a first end and a second end. The first end forms a first engagement structure and the second end forms a second engagement structure. The first engagement structure of the first connector link is sized and shaped to be received by the second engagement structure of the second connector link. The expansion or compression member is configured to engage with at least one of the first connector link and the second connector link when the first engagement structure of the first connector link is received by the second engagement structure of the second connector link to move the modular mandibular prosthetic from the unlocked state to the locked state. 
     Various embodiments of the various aspects are described. A level of resistance to moving the first connector link relative to the second connector link may increase when the modular mandibular prosthetic is moved from the unlocked state to the locked state. The body of each of the first connector link and the second connector link may have a general cuboidal shape. The body of each of the first connector link and the second connector link may have a unitary structure. The body of each of the first connector link and the second connector link may have a monolithic structure. The first engagement structure of the first connector link may have a convex spherical shape and the second engagement structure of the second connector link may have a concave spherical shape. The first engagement structure of the first connector link may have a ball shape and the second engagement structure of the second connector link may have a socket shape. 
     The body of the first connector link may have a receptacle disposed between the first end and the second end, the receptacle being sized and shaped to receive a dental implant. The receptacle may be disposed between the first engagement structure and the second engagement structure. The modular mandibular prosthetic may further comprise at least one end attachment, the at least one end attachment being configured to connect an end of the portion of the modular mandibular prosthetic to a portion of the patient&#39;s mandible. The at least one end attachment may have a generally planar shape. The second engagement structure of the first connector link may be sized and shaped to receive the first engagement structure of the second connector link. 
     The expansion or compression member may be a screw. The expansion or compression member may engage with the first connector link by rotating the expansion or compression member relative to the first connector link. The expansion or compression member may engage with the body of the first connector link by penetrating the body. The expansion or compression member may penetrate the first engagement member of the first connector link at a location. The location may be between the body of the first connector link and the body of the second connector link. The expansion or compression member may engage with the second connector link by rotating the expansion or compression member relative to the second connector link. 
     The first connector link may be movable with respect to the second connector link when the modular mandibular prosthetic is in the unlocked state. The movement of the first connector link may be a swivel. The swivel may be in three dimensions. The first connector link may be fixed with respect to the second connector link when the portion of the modular mandibular prosthetic is in the locked state. 
     The second engagement structure of the second connector link may be sized and shaped to receive the first engagement structure of the first connector link in at least a first position and a second position so that an overall length of the first connector link and the second connector link when the modular mandibular prosthetic is in the first position is greater than an overall length of the first connector link and the second connector link when the modular mandibular prosthetic is in the second position. Moving between the first position and the second position may be achieved by rotating the first connector link relative to the second connector link. Moving between the first position and the second position may be achieved by axially moving the first connector link relative to the second connector link. 
     The expansion or compression member may be releasable. The portion of the modular mandibular prosthetic may maintain an assembled state when the modular mandibular prosthetic is in the unlocked state and the expansion or compression member is disengaged from both of the first connector link and the second connector link. The patient&#39;s mandible may have a lingual surface and a facial surface, and the first engagement structure and the second engagement structure of each of the first connector link and the second connector link may lie in a plane between the lingual surface and the facial surface. 
     In another aspect, a modular mandibular prosthetic for replacing at least a portion of a patient&#39;s mandible is described. The patient&#39;s mandible has a lingual surface and a facial surface. The prosthetic comprises at least a first connector link and a second connector link. Both of the first and second connector links form at least a portion of the modular mandibular prosthetic. The modular mandibular prosthetic has an unlocked state and a locked state. Each of the first and second connector links has a body, a first end and a second end. The first end forms a first engagement structure and the second end forming a second engagement structure. The first engagement structure of the first connector link is configured to be received by the second engagement structure of the second connector link. The first engagement structure and the second engagement structure lie in a plane between the lingual surface and the facial surface. The modular mandibular prosthetic further comprises an expansion or compression member configured to engage with at least one of the first connector link and the second connector link when the first engagement structure of the first connector link is received by the second engagement structure of the second connector link. 
     In another aspect, a modular mandibular prosthetic for replacing at least a portion of a patient&#39;s mandible is described. The modular mandibular prosthetic has an unlocked state and a locked state. The modular mandibular prosthetic comprises a first connector link that has a body, a first end and a second end. The first end forms a first engagement structure and the second end forms a second engagement structure. The first connector link forms at least a first portion of the modular mandibular prosthetic. The modular mandibular prosthetic further comprises a second connector link that has a body, a first end and a second end. The first end forms a first engagement structure and the second end forms a second engagement structure. The second connector link forms at least a second portion of the modular mandibular prosthetic. The first engagement structure of the first connector link is sized and shaped to be received by the second engagement structure of the second connector link when the modular mandibular prosthetic is in both the unlocked state and the locked state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure. 
         FIG. 1  is a perspective view of an embodiment of a modular mandibular prosthetic having connecting links with spherical engagement structures and shown connecting two portions of a mandible. 
         FIG. 2  is a perspective view of another embodiment of a modular mandibular prosthetic having connecting links with spherical engagement structures and shown connecting a mandible with a temporomandibular joint. 
         FIGS. 3A and 3B  are perspective views of various configurations achievable by various embodiments of a modular mandibular prosthetic. 
         FIGS. 3C and 3D  are photographs of various prototype embodiments of a modular mandibular prosthetic. 
         FIGS. 4 and 5  are perspective views of embodiments of a modular mandibular prosthetic having spherical and mushroom shaped engagement structures respectively and shown disconnected. 
         FIGS. 6A and 6B  are various views of embodiments of connecting links that may be used with the various modular mandibular prosthetics described herein. 
         FIGS. 7A-7C  are perspective views of another embodiment of a modular mandibular prosthetic having swivel engagement structures and shown in various configurations. 
         FIG. 8  is a perspective view of another embodiment of a modular mandible prosthetic having swivel engagement structures and shown disconnected. 
         FIG. 9A  is a perspective view of an embodiment of a connecting link having a receptacle configured to receive a dental implant. In certain embodiments, the connecting link already incorporates the dental implant. The dental implant is also referred to as a screw or cylinder. A dental crown can be subsequently placed on the dental implant or screw. The connecting link may be used with the various modular mandibular prosthetics described herein. 
         FIG. 9B  is perspective view of the connecting link of  FIG. 9A  having the dental implant received into the receptacle with the dental crown secured thereto. 
         FIG. 10  is a perspective view of an embodiment of a connecting link having a spherical engagement structure with various locations configured to receive an expansion or compression member and that may be used with the various modular mandibular prosthetics described herein. 
         FIG. 11  is a perspective view of an embodiment of a modular mandibular prosthetic with a connecting link having a mushroom shaped engagement structure with various locations configured to receive an expansion or compression member and that may be used with the various modular mandibular prosthetics described herein. 
         FIGS. 12A and 12B  are sequential side views of a spherical engagement structure before and after tightening of an expansion or compression member into the engagement structure. 
         FIGS. 13A and 13B  are cross-section views of two connecting links having engagement structures which allow axial fine adjustments of length, and shown in first and second axial positions. 
         FIGS. 14A and 14B  are cross-section views of two connecting links having engagement structures with first and second positioning portions for coarse adjustments and shown in first and second axial positions. 
         FIGS. 15A and 15B  are various views of an embodiment of a connecting link having various trabeculated tissue surfaces to encourage mandible tissue ingrowth, or for placement of graft material. 
         FIG. 16  is a perspective view of an embodiment of a body having a hollow structure with a system of trusses for stability and to decrease the weight, and encourage mandibular tissue ingrowth or graft material. The body may be used with the various modular mandibular prosthetics described herein. 
         FIGS. 17A and 17B  are sequential side views of an embodiment of a tool that may be used to connect the links together for the various modular mandibular prosthetics described herein. 
         FIG. 18  is a perspective view of another embodiment of a modular mandibular prosthetic having an integral mandible attachment at ends thereof and shown prior to connecting the links together. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following detailed description is directed to certain specific embodiments of the development. Reference in this specification to “one embodiment,” “an. embodiment,” or “in some embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrases “one embodiment,” “an embodiment,” or “in some embodiments” in various places in the specification are not necessarily all referring to the same embodiment of the prosthetic, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but may not be requirements for other embodiments. 
     Various embodiments will now be described with reference to the accompanying figures, wherein like numerals refer to like elements throughout. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the development. Furthermore, embodiments of the development may include several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the invention described herein. 
       FIG. 1  is a perspective view of an embodiment of a modular mandibular prosthetic  100 . In certain embodiments, the prosthetic  100  includes connecting links  110 ,  112 . In certain embodiments, the connecting links  110 ,  112  include spherical engagement structures  130 . The prosthetic  100  is shown connecting two portions of a mandible  10 . Any features described with respect to an embodiment of the prosthetic may apply to any other embodiment. Thus, any features of the prosthetic  100  may apply to other embodiments described herein, and vice versa. 
     The prosthetic  100  may be used for a mandibulectomy or segmental mandibulectomy (used interchangeably herein) A mandibulectomy is the removal of all or part of the mandible  10  or jawbone. The mandibulectomy may be used in various settings, including infectious etiologies (e.g., osteomyelitis), osteoradionecrosis, or a benign (e.g., ameloblastoma) or malignant neoplastic process (e.g., invasive squamous cell carcinoma) that involves the jaw. A mandibulectomy may be used for severe oral and maxillofacial trauma if a section of the mandible  10  is not salvageable. 
     As shown in  FIG. 1 , the prosthetic  100  is shown implanted with remaining portions of the mandible  10 . The mandible  10  forms the lower jaw and holds the lower teeth  22  in place. The mandible sits beneath the maxilla. The mandible  10  is a single bone in articulation with the skull by bilateral temporomandibular joints  24 . 
     The mandible  10  includes bilateral condylar heads (joints) and necks, bilateral rami  12  connected to bilateral mandibular bodies  14  and that are located on either side of an anterior symphyseal region that includes the chin  16 . The mandible  10  includes an outer (lateral) or facial surface  18  and an opposite inner (medial) or lingual surface  20 . The mandible  10  has a largely consistent curved shape in multiple planes. The temporomandibular joint  24  is a hinged portion that articulates the mandible  10  to the temporal bones of the skull, which are in front of each ear. 
     The prosthetic  100  is shown connecting a forward portion of the body  14  (or an outer portion of the chin  16 ) to the adjacent ramus  12 . The prosthetic  100  may be implanted into existing tissue of the patient that surrounds the prosthetic  100 . In some embodiments, the entire bone and tissue of the defective portion of the mandible  10  may be removed completely and replaced by the prosthetic  100 , and either biocompatible tissue replacement and/or natural tissue may be placed or caused to grow around the prosthetic  100 . The mandible  10  may have a section between references  13  and  15  removed or partially removed, and the prosthetic  100  may be implanted between the references  13  and  15 . The prosthetic  100  may extend from the reference  13  to the reference  15 . The prosthetic  100  may extend along this direction and have any desirable arc length. 
     The various embodiments of prosthetics described herein, such as the prosthetic  100 , provide various uniquely desirable features for mandibulectomies and other suitable procedures. For example, in certain embodiments, the prosthetic  100  provides a “buildable” prosthetic to fit any mandibular defect and that may be less expensive than existing prosthetics. In certain embodiments, the prosthetic  100  can be sized to an average mandible so that the prosthetic  100  has wide patient applicability. In certain embodiments, the prosthetic  100  better re-establishes mandibular width and height, as well as the esthetic curvature of the mandible  10 . In certain embodiments, the prosthetic  100  is better able to withstand forces of mastication without fracture, compared to a titanium plate alone. In certain embodiments, the prosthetic  100  has a finite number of “stock” pieces needed to recreate the missing portion of the mandible  10 . In certain embodiments, the prosthetic  100  has the possibility for various iterations and applications, such as the possibility for integrating implants. In certain embodiments, the prosthetic  100  may simplify the reconstructive algorithm for mandibular defects. In certain embodiments, the prosthetic  100  may be used for palliative and staged reconstruction where the morbidity of conventional methods are outweighed by their inherent benefits. Use of the prosthetic  100  may supplant the need for autogenous reconstruction. 
     The prosthetic  100  may find applicability in the reconstruction of defects in other regions of the body, since the concept is based on a simple, low-cost module that offers innumerable options in reconstructing varied bony defects while minimizing morbidity to patients. 
     The structure of the prosthetic  100  may include two or more inter-articulating base pieces or connecting inner links  110 . The prosthetic may include one or more end links  112 . As shown, the prosthetic  100  includes three inner links HO and two end links  112 . There may be one, two, three, four, five, six, seven, eight, nine, ten, or more inner links  110 . There may be zero, one, or two end links  112 . Each link  110 ,  112  includes a body  120 . One or more of the links  110 ,  112  includes an engagement structure  130 . The inner links  110  may be connected using the engagement structures  130  to a form a desired length, and the end links  112  may be connected and located on the two ends of a formed string of connected inner links  110 . The width and height of the links  110 ,  112  may be based on an anatomical average of mandibular widths and heights, which may eliminate dead-space. 
     In certain embodiments, the body  120  has a generally cubed or cuboidal shape as shown. In other embodiments, the body  120  has a cylindrical shape. Of course the shape of the body  120  is not limited and can have any other desirable shape. The corners and edges of the body  120  can be chamfered, shaped, and/or rounded to prevent clinical issues such as, for example, damage to overlying tissue (dehiscence). 
     The body  120  may be formed of a biocompatible material, or may be used in conjunction with novel tissue engineering. The body  120  may be a unitary structure. The body  120  may be a monolithic structure. For example, the body  120  may be formed from a single piece of material or additively manufactured. In certain embodiments, the body  120  has six faces. In certain embodiments, the body  120  may have a square or rectangular face or faces. 
     For the sake of description, a local reference XYZ axis system is shown in  FIG. 1  relative to the forward/left-most end link  112 . Similar reference systems may be applied to the other links  110 ,  112 . The axis system includes an X axis extending along a first length of the body  120 , a Y axis extending outwardly away from the mandible  10 , and a Z axis that is perpendicular to the X and Y axes. In certain embodiments, the body  120  has a cuboidal shape that is longer in the Z-direction than the X-direction, which is longer than the Y-direction. Any other relationship between the lengths of the sides of the body  120  may be implemented. For example, the ascending or descending order of the lengths of the sides of the body  120  may be X, Y, Z, or X, Z, Y, or Y, Z, X, or Y, X, Z, or Z, Y, X, or Z, X, Y. Two or more of any of these lengths may be the same or substantially the same length. In some embodiments, all three of the lengths of the sides of the body  120  may be equal or substantially equal. As mentioned above, the bodies  120  may have cuboidal shapes with chamfered edges, other suitable shapes, or combinations thereof as further described herein. 
     The design may use various types of engagement structures  130 , such as a spherical connector as shown, to connect the links  110 ,  112  together. The engagement structure  130  has a convex spherical shape. The engagement structure  130  may therefore bulge or otherwise extend outward away from the body  120  and have a spherical or otherwise rounded outer surface. 
     The engagement structure  130  may be attached at a first end of the body  120  and connect with a receiving portion  132  at a second end of an adjacent body  120 . The engagement structure  130  may be a first engagement structure and the receiving portion  132  may be a second engagement structure that engage with each other to connect two adjacent links  110 ,  112 . The receiving portion  132  may have a corresponding concave shape. The receiving portion  132  may therefore extend inward into the body  120  and form a spherical or otherwise rounded inward surface. Each of the inner links  110  may include the engagement structure  130  on the first end of the body  120  and the corresponding receiving portion  132  on a second opposite end of the body  120 . When implanted, the engagement structure  130  and the receiving portion  132  of each of the links  110 ,  112  may be located between the lingual surface  20  and the facial surface  18 . The engagement structure  130  and the receiving portion  132  of each of the links  110 ,  112  may lie in a plane located between the lingual surface  20  and the facial surface  18 . 
     The receiving portion  132  receives and attaches with an adjacent engagement structure  130 . The engagement structure  130  may be secured with the receiving portion  132  using a variety of different expansion or compression members, as further described herein. This and the other engagement designs described herein allow for a three-dimensional rotational movement of the links  110 ,  112 , allowing for the reconstruction of the missing portion of the mandible  10  while recreating its natural curvature, with subsequent locking and rigidizing of the prosthetic  100  in a desired and final configuration. The engagement structure  130  and receiving portion  132  may be implemented as a configurable and securable “ball and socket” connection mechanism. In certain embodiments, a ball and socket mechanism can allow for free movement to form any curvature. In some embodiments, the engagement structure  130  may have a ball shape and the receiving portion  132  may have a socket shape, as further described herein, for example with respect to  FIGS. 7-10 . 
     In certain embodiments, the end links  112  may include the receiving portion  132  on a first end of the body  120 . The end links  112  may not have the engagement structure  130  on the opposite second end of the body  120 . In certain embodiments, the second end of the body  120  may be configured to be attached to one or more end attachments  102 , such as the elongated, planar attachment members as shown, to attach to the mandible  10 . 
     In certain embodiments, the sizing and use of the prosthetic  100  may be based on measurement of the mandibular defect. In certain embodiments, the surgeon may then assemble the needed links  110 ,  112  to ill the defect while re-establishing the mandibular form, rotating the pieces at the ball-and-socket interface. In certain embodiments, once satisfied with the reconstruction, the surgeon then locks the links  110 ,  112  in place to render the reconstruction rigid. In certain embodiments, the links  110 ,  112  may be locked by using an expansion system where a pre-placed expansion or compression member, such as a screw (see  FIGS. 14-15B ), at the center of the engagement structure  130  is tightened to cause microexpansion of the body  120  of the links  110 ,  112 , and thus locking the links  110 ,  112  along the friction interface. In some embodiments, a compression system may be used where expansion or compression members themselves are pre-placed in the bodies  120 , such as cuboidal prisms, and when tightened will compress the engagement structure  130 , such as a sphere, in place. 
       FIG. 2  is a perspective view of another embodiment of a modular mandibular prosthetic  200 . The prosthetic  200  may have the same or similar features as the prosthetic  100 , and vice versa. In certain embodiments, the prosthetic  200  includes four of the connecting inner links  110 . In certain embodiments, the prosthetic  200  at a first end thereof includes one end link  112  attached to the body  14  (or chin portion  16  or anywhere in the mandible) by the end attachments  102 . In certain embodiments, the prosthetic  200  at a second end thereof includes another embodiment of an end link  140 . The end link  140  includes a body  122 . The body  122  includes the engagement structure  130 . The engagement structure  130  is located on a first end of the body  122 . The engagement structure  130  engages with the receiving portion  132  of the adjacent inner link  110 . In certain embodiments, the adjacent inner link  110  receives an expansion or compression member as described to lock the inner link  110  in place with the end link  140 . In certain embodiments, the end link  140  may also receive an expansion or compression member. In some embodiments, the end link  140  may include the receiving portion  132 , and the adjacent inner link  110  may include the engagement structure  130 . 
     In certain embodiments, the end link  140  includes another embodiment of an attachment  131 . In certain embodiments, the attachment  131  has a bulb shape. For example, the attachment  131  can include a narrow necked region  133  extending from the body  120  to an outer and wider spherical end portion  134 . The attachment  131  may have a variety of other suitable shapes and configurations. The attachment  131  is located on an end of the body  122  of the end link  140  that is opposite the adjacent inner link  110 . In certain embodiments, the attachment  131  extends outwardly from the end link  140 . In certain embodiments, the attachment  131  is configured to become a replacement of the condylar head portion of the temporomandibular joint (TMJ)  24 . The TMJ  24  is shown in schematic form for clarity. In certain embodiments, the attachment  131  may instead attach to the mandible  10 . In certain embodiments, the attachment  131  may attach to the ramus  12 . In some embodiments, the prosthetic  200  may include the end link  112  in place of the end link  140 . 
       FIGS. 3A and 3B  are perspective views of other embodiments of a modular mandibular prosthetic  300  and  301 , respectively. The prosthetics  300 ,  301  may have the same or similar features as any other prosthetic described herein, such as the prosthetics  100  and/or  200 , and vice versa. 
     As shown in  FIG. 3A , the prosthetic  300  includes three of the inner links  110  and two end links  112 . The bodies  120  of the links  110 ,  112  are connected in series and have the engagement structures  130  secured with corresponding receiving portions  132  of the adjacent links  110  or  112 . The prosthetic  300  has been configured to have a bent shape as shown. Prior to locking the prosthetic  300 , the links  110 ,  112  may extend from a first end  302  to a second end  304 . Central axes  303  and  305  defined respectively by the end links  112  at the ends  302  and  304  may be angled with respect to each other. 
     In certain embodiments, the engagement structures  130  each further include an opening  135 . In certain embodiments, the opening  135  is configured to receive an expansion or compression member therein to lock the prosthetic  300  in a desired configuration. In certain embodiments, the opening  135  may be threaded or smooth. In certain embodiments, the opening  135  may receive a fastener such as a screw, or the screw may be pre-placed at a depth just short of maximum depth, so that with small additional turns of the screw to further seat the screw, will provide the microexpansion necessary to lock the embodiment in place. In certain embodiments, the opening  135  may expand slightly after receiving the expansion or compression member to cause the prosthetic  300  to assume a locked configuration. Further details of example expansion or compression members and corresponding openings in the engagement structures for the expansion or compression members are further described herein, for example with respect to  FIGS. 11-15B . 
     As shown in  FIG. 3B , the prosthetic  301  includes a link  306  having a body  320  and an engagement structure  330 . There may be four links  306  as shown, or greater or fewer than four. In certain embodiments, the links  306  each include a projection  322  extending upwardly from a corresponding body  320 . The projections  322  may be configured to attach with a prosthetic tooth. 
     In certain embodiments, the prosthetic  301  includes a link  308  having the body  320  and the engagement structure  330 . There may be two links  308  as shown, or greater or fewer than two. The links  308  may be attached to the end of the connected links  306 . Any combination, number and order of the links  306  and  308  may be implemented. 
     The engagement structures  330  may secure with adjacent engagement structures, such as receiving portions, as described. In certain embodiments, the engagement structures  330  may be formed of compliant material. The material may be curable to transition from compliant to rigid after sizing or after implantation. The engagement structures  330  may extend from both ends of the prosthetic  310  as shown, or from only one or none of the ends. 
     The bodies  320  include chamfered edges  324 ,  326 ,  327 ,  328  on a top end of the bodies  320 . The lower opposite end of the bodies  320  also include the chamfered edges. All four sides of a face of the body  320  may include the chamfered edges  324 ,  326 ,  327 ,  328  as shown. In some embodiments, one, two, three, or none of the edges of a side of the body  320  may include the chamfered edges  324 ,  326 ,  327 ,  328 . The corners and edges of the body  320  can be chamfered, shaped, and/or rounded to prevent clinical issues such as, for example, damage to overlying tissue (dehiscence). 
       FIGS. 3C and 3D  are photographs of other embodiments of a modular mandibular prosthetic  307  and  309 , respectively. The prosthetics  307 ,  309  may have the same or similar features as any other prosthetic described herein, such as the prosthetics  100 ,  200 ,  300 , and/or  301 , and vice versa. In certain embodiments, the prosthetic  307  includes the links  306  and  308  connected using engagement structures  130 . In certain embodiments, the prosthetic  309  includes the links  110  and  112  connected using engagement structures  130 . The bodies of the links  110 ,  112  include chamfered edges, as described with respect to  FIG. 3B . 
       FIGS. 4 and 5  are perspective views of other embodiments of a modular mandibular prosthetic  400  and  500 , respectively shown in disconnected configurations. The prosthetics  400  and  500  may have the same or similar features as any other prosthetic described herein, such as the prosthetics  100 ,  200 ,  300 ,  301 ,  307 , and/or  309 , and vice versa. 
     As shown in  FIG. 4 , in certain embodiments, the prosthetic  400  includes inner links  410  and end links  412  having the bodies  120 . In certain embodiments, the inner links  410  and the right-most end link  412  (as oriented) include the receiving portions  132  formed as spherical concave features. In certain embodiments, the inner links  410  and the left-most end link  412  (as oriented) include the engagement structure  130  formed as a spherical convex feature. 
     As shown in  FIG. 5 , in certain embodiments, the prosthetic  500  includes inner links  510  and end links  512  having bodies  520 . In certain embodiments, the inner links  510  and the left-most end link  512  (as oriented) include engagement structures  530  formed as mushroom shaped engagement structures. For example, the engagement structures  530  include a relatively narrowed neck region  531  extending outwardly away from an end of a corresponding body  520 . A wider end portion  533  is located on the end of the neck region  531  that is farthest from the body  520 . The end portion  533  may have a partially spherical volume forming an outer rounded surface. 
     In certain embodiments, the inner links  510  and the right-most end link  512  (as oriented) include receiving portions  532  corresponding to the engagement structures  530 . In certain embodiments, the receiving portions  532  include a narrow opening  534  extending inward into the body  520  to a wider opening region  535 . In certain embodiments, the narrow opening  534  corresponds in size and shape to the narrowed neck region  531  of the engagement structure  530 . The wider opening region  535  corresponds in size and shape to the wider end portion  533  of the engagement structure  530 . 
     The engagement structure  530  and/or the receiving portion  532  may be flexible to allow the relatively wider end portion  533  of the engagement structure  530  to squeeze through the narrow opening  534  of the receiving portion  532 . In certain embodiments, the links  510 ,  512  may be rotatable relative to each other after the receiving portions  532  have received corresponding engagement structures  530  therein and prior to locking. 
       FIGS. 6A and 6B  are side and perspective views respectively of other embodiments of modular mandibular prosthetics  600  and  601  respectively, shown prior to connecting the connectable links together. The prosthetics  600  and  601  may have the same or similar features as any other prosthetic described herein, such as the prosthetics  100 ,  200 ,  300 ,  301 ,  307 ,  309 ,  400 , and/or  500 , and vice versa. 
     As shown in  FIG. 6A , in certain embodiments, the prosthetic  600  includes the links  306 ,  308  having the bodies  320  and the engagement structures  330 . The links  306  include the projections  322 . As shown in  FIG. 6B , in certain embodiments, the prosthetic  601  includes the links  306 ,  308  having the bodies  320  and the engagement structures  330 . Further, the links  306 ,  308  include trabeculated tissue surfaces  321  to encourage mandible tissue ingrowth, or as scaffolding for grafting materials to encourage native mandibular growth. The bodies  320  and the engagement structures  330  include the surfaces  321 . The surfaces  321  may be scaffolding intended to promote tissue growth for biocompatibility and further securement of the prosthetic in the mandible. The surfaces may also be coarse or smooth to encourage a friction tight locking interface. 
       FIGS. 7A-7C  are perspective views of another embodiment of a modular mandibular prosthetic  700 .  FIGS. 7A and 7B  depict the prosthetic  700  in various connected. configurations.  FIG. 7C  depicts the prosthetic  700  in an unconnected configuration. The prosthetic  700  may have the same or similar features as any other prosthetic described herein, such as the prosthetics  100 ,  200 ,  300 ,  301 ,  307 ,  309 ,  400 .  500 ,  600 , or  601 , and vice versa. 
     In certain embodiments, the prosthetic  700  includes links  706 ,  708  including bodies  720  with chamfered or rounded edges, and with engagement structures  730  and/or receiving portions  732 . The links  706  include bodies  720  having projections  722 . In certain embodiments, the engagement structures  730  are swivel-type engagement structures. In certain embodiments, each engagement structure  730  includes a neck  731  extending outwardly form the body  720  to a spherical end portion  733 . In certain embodiments, the neck  731  has a narrower width than a maximum width of the spherical end portion  733 . The neck  731  may have a circular profile as shown, or other rounded profile. The spherical end portion  733  may include a majority of a complete sphere, for example more than 50% of a sphere. The spherical end portion  733  is received into the receiving portion  732  of an adjacent link  706  or  708  and is secured therein. 
       FIG. 8  is a perspective view of another embodiment of a modular mandible prosthetic  800 . The prosthetic  800  may have the same or similar features as any other prosthetic described herein, such as the prosthetics  100 ,  200 ,  300 ,  301 ,  307 ,  309 ,  400 ,  500 ,  600 ,  601 , or  700 , and vice versa. In certain embodiments, the prosthetic  800  includes the swivel engagement structures  730 . In certain embodiments, the prosthetic  800  includes links  806  and  808 , which are shown disconnected from each other. The links  806 ,  808  include cuboidal bodies  820  but are not limited to the illustrated shape. 
     Some or all of the bodies  820  may include a receiving portion  832  and/or the engagement structures  730  extending outwardly therefrom. In certain embodiments, the links  806  include projections  822 . In certain embodiments, the bodies  820  are cuboidal, with one of the bodies  820  having chamfered edges, and the remaining bodies not having chamfered edges. More than one, or none, of the bodies may have the chamfered edges. 
       FIGS. 9A and 9B  are perspective views of an embodiment of a connecting link  910 . The link  910  may have the same or similar features as any other links described herein, such as the links  110 ,  112 ,  306 ,  308 ,  410 ,  412 ,  510 ,  512 ,  706 ,  708 ,  806  or  808 , and vice versa. The link  910  includes a body  920  having a receiving portion  932  and an engagement structure  930 . 
     In certain embodiments, the body  920  further includes a receptacle  950 . In certain embodiments, the receptacle  950  extends downward from a first surface  921 , such as an upper surface, of the body  920  into the body  920 . In certain embodiments, the receptacle  950  has a frustoconical shape that tapers to a smaller width into the body  920 . The receptacle  950  may be cylindrical, a segmented polygonal shape, other suitable shapes, or combinations thereof. The receptacle  950  may have an outer rounded wall as shown. In certain embodiments, the body  920  can have the implant already manufactured into the design. In such an embodiment, the crown is then screwed onto the implant. 
     The receptacle  950 , for example the outer wall, defines a channel  952 . The channel  952  may be frustoconical as shown, or have the other shapes described above with respect to the receptacle  950 . In certain embodiments, the channel  952  extends from an opening  951  at an entrance to the channel  952  located at the upper surface  921  of the body  920 . The channel  952  extends into the body  920 . In certain embodiments, the channel  952  terminates above the opposite second surface  922 , such as a lower surface, of the body  920 . The channel  952  may extend farther or less far than shown, for example for 25%, 50%, 75%, or for other percentages, of the depth of the body  920  in the direction from the first surface  921  to the second surface  922 . 
     As shown in  FIG. 9B , the channel  952  can be configured to receive an implant  954 . The implant  954  may be a tooth, such as a prosthetic tooth. In certain embodiments, the implant  954  may be secured with the receptacle  950  via friction fitting, bonding, fastening, screwing, using other suitable mechanical attachment methods, or combinations thereof. 
     In some embodiments, one or more receptacles  950  may be included and configured to receive an expansion or compression member therein, as described in further detail herein, for example with respect to  FIGS. 11-12B . 
       FIG. 10  is a perspective view of another embodiment of a connecting link  1010 . The link  1010  may have the same or similar features as any other links described herein, such as the links  110 ,  112 ,  306 ,  308 ,  410 ,  412 ,  510 ,  512 ,  706 ,  708 ,  806 ,  808  or  910 , and vice versa. 
     The link  1010  includes a body  1020  having an engagement structure  1030 . In certain embodiments, the engagement structure  1030  may be received into a receiving portion  1032  of the body  1020 . In certain embodiments, the engagement structure  1030  includes a plurality of targets  1035 . There are five targets  1035 . There may be one, two, three, four, six, seven, eight, nine, ten or more of the targets  1035 . The targets  1035  may be regions of the engagement structure  1030  configured to each receive an expansion or compression member therein to cause the prosthetic, in which the link  1010  is used, to take a locked state. The targets  1035  may include openings, such as holes, channels, shallow grooves, or the like, into which expansion or compression members may be received, as further described herein. There may be multiple targets  1035  within the spherical subunit to accommodate the fact that with rotation of the ball and socket interface, the exposed targets  1035  may not always be in the standard location. With multiple targets  1035 , there will be more opportunities for the expansion or compression member to be exposed for easy access. 
       FIG. 11  is a perspective view another embodiment of a modular mandibular prosthetic  1100 . In certain embodiments, the prosthetic  1100  includes two connecting links  1110 . The prosthetic  1100  may include more than two links  1110 . Each link  1110  includes a body  1120  having a first surface  1121 , such as an upper surface, and a second surface  1122 , such as a lower surface. The first and second surfaces  1121 ,  1122  may be on any of the outer surfaces or faces of the body  1120 . 
     The left link  1110  (as oriented in the figure) includes an engagement structure  1130 . In certain embodiments, the engagement structure  1130  includes a mushroom shaped configuration, which may be similar to the engagement structure  530  as described with respect to  FIG. 5 . Any of the other engagement structures described herein may be used with the links  1110 . 
     In certain embodiments, the prosthetic  1100  includes a plurality of expansion or compression members  1150 . There are four expansion or compression members  1150  as shown. There may be one, two, three, five, six, seven, eight, nine, ten or more expansion or compression members  1150 . The expansion or compression members  1150  may include an opening  1151  and define a channel  1152  therethrough, similar to the receptacles  950 . In some embodiments, the expansion or compression members  1150  may not include the opening  1151  and/or channel  1152 . The expansion or compression members  1150  may include attachment features, such as slots or grooves, at outer ends thereof and that are configured to be mechanically grabbed by a tool, such as a screw driver or drill, for fastening, e.g., rotating, the expansion or compression members  1150  into the body  1120 . In certain embodiments, the body  1120  may include openings at the surfaces  1121  and/or  1122  configured to facilitate entry and securement of the expansion or compression members  1150 . In certain embodiments, the openings in the bodies  1120  may be pilot holes, or holes with smaller widths than the expansion or compression members  1150 . 
     In certain embodiments, as the expansion or compression members  1150  are secured with the body  1120 , the expansion or compression member  1150  may expand. In some embodiments, the portions of the body  1120  surrounding the expansion or compression member  1150  may expand. The body  1120  may be formed of a material that will expand to secure the expansion or compression member  1150  therein without cracking or otherwise failing. In certain embodiments, the expansion or compression member  1150  may have a larger width and/or depth than an opening in the body  1120  into which the expansion or compression member  1150  is secured, such that the adjacent region of the body  1120  expands slightly. 
     The expansion or compression members  1150  are engaged with the body  1120  and with the engagement structure  1130 . The engagement structure  1130  may include various targets or locations, such as the targets  1035  described with respect to  FIG. 10 , that may receive the expansion or compression member  1150  therein. 
     As the expansion or compression members  1150  are secured with the engagement structure  1130 , the engagement structure  1130  expands. The portion of the engagement structure  1130  surrounding the expansion or compression member  1150  may expand. The engagement structure  1130  may be formed of a material that will expand to secure the expansion or compression member  1150  therein without cracking or otherwise failing. The expansion or compression member  1150  may have a larger width and/or depth than an opening in the engagement structure  1130  into which the expansion or compression member  1150  is secured, such that the adjacent region of the engagement structure  1130  expands slightly. 
     In certain embodiments, the expansion or compression member  1150  may fixedly attach to the narrow neck region as well as the wider end portion of the mushroom shaped engagement structure  1130 . In certain embodiments, the expansion or compression member  1150  may engage with a spherical portion, a bulbous portion, a cylindrical portion, or any other portion, of the various engagement structures described herein. 
     In certain embodiments, the expansion or compression member  1150  thus fixedly attaches to both the body  112 . 0  and to the engagement structure  1130 . In this manner the orientation of the engagement structure  1150  is fixed relative to the body  1120 . Thus the prosthetic links  1110  can be oriented in a desired configuration by the surgeon and then the expansion or compression members  1150  secured with the prosthetic  1100  to cause the prosthetic  1100  to take a rigid, locked state. In the locked state, the links  1110  of the prosthetic  1100  are not freely movable relative to each other. In certain embodiments, “freely movable” means that at least more than the force due to gravity acting on the links  1110  is required to move one link  1110  relative to the adjacent link  1110 . In certain other embodiments, “freely movable” means that the prosthetic  1100  can also withstand the forces of mastication acting on the links  1110  before one link  1110  moves relative to the adjacent link  1110 . 
     A level of resistance to moving the first connector link  1110  relative to the second connector link  1110  increases when the prosthetic  1100  is moved from the unlocked state to the locked state. The level of resistance to movement may therefore be increased after engaging the expansion or compression members  1150  with the prosthetic  1100 . In certain embodiments, the expansion or compression members  1150  may be engaged with the body  1120  and the engagement structure  1130  to increase the level of resistance. 
       FIGS. 12A and 12B  are sequential side views of a spherical engagement structure  1230  shown respectively before and after tightening of the expansion or compression member  1150  into the engagement structure  1230 . The engagement structure  1230  may include any of the features of the various engagement structures described herein, such as the engagement structure  130 ,  330 ,  530 ,  730 .  930 ,  1030  or  1130 , and vice versa. 
     As shown in  FIG. 12A , prior to engaging the expansion or compression member  1150  with the engagement structure  1230 , a gap  1232  exists between an outer surface  1153  of the expansion or compression member  1150  and an opening  1231  of the engagement structure  1230 . As shown in  FIG. 12B , after engaging the expansion or compression member  1150  with the engagement structure  1230 , for example by rotating as shown, the gap  1232  is entirely or partially gone and the engagement structure  1230  expands in microincrements. The engagement structure  1230  may expand in the region surrounding the expansion or compression member  1150 . The engagement structure  1230  may expand in or more directions by 0.001″ (inches) or more, by 0.005″ or more, by 0.010″ or more, by 0.50″ or more, by 0.01 inches or more, or by greater amounts. 
       FIGS. 13A and 13B  are cross-section views of other embodiments of two connecting links  1320  having an engagement structure  1330  and corresponding receiving portion  1332 . The engagement structure  1330  includes a narrow neck  1331  and a wider end portion  1333 . The engagement structure  1330  and receiving portion  1332  may be similar respectively to the engagement structure  730  and receiving portion  732  or  832  described herein with respect to  FIGS. 7A-8 . The receiving portion  1332  includes an opening with a longer axial length than the corresponding axial length of the end portion  1333  of the engagement structure  1330 . The width of the receiving portion  1332  may be similarly over-sized. There is thus axial movement that allows for fine adjustments. 
     In  FIGS. 13A and 13B , the links  1320  are shown respectively in first and second axial positions. In the first axial position, the bodies  1320  are separated by a first distance In the second axial position, the bodies  1320  are separated by a second distance D 2 . The first distance Di is greater than the second distance D 2 . The axial movement between the receiving portion  1332  and the engagement structure  1330  allows for this fine adjustment. The distances D 1  and/or D 2  may be 0.1″ (inches), 0.15″, 0.2″, 0.25″, 0.3″, 0.35″, 0.4″, 0.45″, 0.5″, about any of these values, between any of these values, or less than or greater than any of these values. The engagement structure  1330  may be configured to receive one or more expansion or compression members in the first or second axial position, or in any position therebetween. In certain embodiments, the engagement structure  1330  may receive the expansion or compression member  1150  as described with respect to  FIGS. 11-12B . 
       FIGS. 14A and 14B  are cross-section views of other embodiments of two connecting links  1420  having an engagement structure  1430  and corresponding receiving portion  1432 . In certain embodiments, the engagement structure  1430  includes a narrow neck  1431  and a wider end portion  1433 . The engagement structure  1430  and receiving portion  1432  may be similar respectively to the engagement structure  730  and receiving portion  732  or  832  described herein with respect to  FIGS. 7A-8 . 
     In certain embodiments, the receiving portion  1432  includes an opening with a longer axial length than the corresponding axial length of the end portion  1433  of the engagement structure  1430 . The width of the receiving portion  1432  maybe similarly over-sized. In certain embodiments, the receiving portion  1432  includes an inner region  1432 A and an outer region  1432 B. The inner region  1432 A is located axially inwardly of the outer region  1432 B. In certain embodiments, each region  1432 A,  1432 B includes a rounded, e.g. spherical or ovular, opening therein configured to receive and secure the end portion  1433  of the engagement structure  1430  therein. There is thus axial movement that allows for coarse adjustments. 
     In  FIGS. 14A and 14B , the links  1420  are shown respectively in first and second axial positions. In the first axial position, the end portion  1433  is located within the outer region  1432 B and the bodies  1320  are separated by a first distance D 1 . In the second axial position, the end portion  1433  is located within the inner region  1432 A and the bodies  1420  are separated by a second distance D 2 . The first distance D 1  is greater than the second distance D 2 . The axial distance between the regions  1432 A,  1432 B and the engagement structure  1430  allows for this coarse or stepped adjustment. The distances D 1  and D 2  may be 0.1″ (inches), 0.25″, 0.5″, 0.75″, about any of these values, between any of these values, or less than or greater than any of these values. 
     In certain embodiments, the engagement structure  1430  may be configured to receive one or more expansion or compression members in the first or second axial position, or in any position therebetween. The engagement structure  1430  may receive the expansion or compression member  1150  as described with respect to  FIGS. 11-12B . In some embodiments, the regions  1432 A,  143213  may include the axial movement described with respect to the receiving portion  1332  ( FIGS. 13A-B ), such that both coarse or stepped adjustments as well as fine adjustments may be made with the prosthetic. 
     The links  1320  and  1420  may have the same or similar features as any other links described herein, such as the links  110 ,  112 ,  306 ,  308 ,  410 ,  412 ,  510 ,  512 ,  706 ,  708 ,  806 ,  808  or  910 , and vice versa. 
       FIGS. 15A and 15B  are various views respectively of embodiments of a connecting link body  1520  and prosthetic  1550  having various trabeculated tissue surfaces  1521  to encourage mandible tissue ingrowth or to act as a scaffolding for grafting and tissue engineered materials.  FIG. 15A  depicts the body  1520  having the tissue surface  1521  on all six sides of the cuboidal body  1520  (only some of the sides are visible). The tissue surface  1521  may be similar to the surface  321  shown and described with respect to  FIG. 6B . 
       FIG. 15B  depicts the prosthetic  1500  including two of the bodies  1520  connected via an engagement structure  1530 . The bodies  1521  and engagement structure  1530  are covered with the tissue or graft surface  1521 . After a period of time, native tissue  1522  has grown onto and around the tissue surfaces  1521  to cover the prosthetic  1500 . 
       FIG. 16  is a perspective view of another embodiment of a body  1620 . The body  1620  may include any of the features of the other bodies describe herein, such as the body  120 ,  320 ,  520 ,  720 ,  820 ,  920 ,  1020 ,  1120 ,  1320 ,  1420  or  1520 , and vice versa. The body  1620  includes a hollow structure. A plurality of beams  1622  (only some of which are labeled for clarity) form the outer structure of the body  1620 . A hollow interior  1625  is defined by the body  1620 . In certain embodiments, the beams  1622  surround and form the interior  1625 . The beams  1622  may include features to attach to or with any of the engagement structures described herein. The beams  1622  may form or support any of the receiving portions described herein. The beams  1622  may provide a scaffolding for graft materials, provide a light-weight alternative, and enhance strength. 
       FIGS. 17A and 17B  are sequential side views of an embodiment of a tool  1701  that may be used to connect the links  1710  of a modular mandibular prosthetic  1700  together. The prosthetic  1700  includes the links  1710  having a body  1720  with an engagement structure  1730  and/or a receiving portion  1732 . The tool  1701  includes gripping portions  1780  and  1781 . Handle portions  1782  and  1783  may be held by a human hand and moved closer together to cause corresponding members  1785 ,  1786  to be rotated about a hinge  1784 . The rotation opens and closes the tool  1701  causing the gripping portions  1780 ,  1781  to move farther apart and closer together. 
     As shown in  FIG. 17B , the gripping portion  1780  may grasp or otherwise contact the body  1720  of one of the links  1710 . The gripping portion  1781  may grasp or otherwise contact the engagement structure of the other of the links  1710 . The handle portions  1782 ,  1783  may then be moved closer together to cause the members  1785 ,  1786  to rotate about the hinge  1784  and thereby bring the gripping portions  1780 ,  1781  closer together. The gripping portions  1780 ,  1781  then cause the links  1 . 710  to be brought closer together and a force is further applied to the handle portions  1782 ,  1783  to cause a compressive force to be applied by the gripping portions  1780 ,  1781  to the links  1710 . The compressive force causes the engagement structure  1730  to engage with the receiving portion  1732 . 
       FIG. 18  is a perspective view of another embodiment of a modular mandibular prosthetic  1800 . The prosthetic  1800  may have the same or similar features as any other prosthetic described herein, such as the prosthetics  100 ,  200 ,  300 ,  301 ,  307 ,  309 ,  400 ,  500 ,  600 ,  601 ,  700 ,  800 ,  1100  or  1800 , and vice versa. The prosthetic  1800  includes inner links  1810  and end links  1812 . In certain embodiments, the links  1810 ,  1812  include the body  520  with the engagement structure  530  and/or the receiving portion  532 . In certain embodiments, the end links  1812  can include other embodiments of the attachments  1802 . In the illustrated embodiment, the attachments  1802  are integral features of the bodies  520 . In certain embodiments, the attachments  1802  may be formed together with the corresponding body  520 , for example machined from the same piece of material or additively manufactured together. The attachment  1802  may be formed separately and then integral connected with the body  520 , for example by adhesive, material melting and solidification, or other suitable techniques. 
     While the above detailed description has shown, described, and pointed out novel features of the invention as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made by those skilled in the art without departing from the spirit of the invention. As will be recognized, the present invention may be embodied within a form that does not provide all of the features and benefits set forth herein, as some features may be used or practiced separately from others. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 
     The methods described herein are illustrative only. A person of skill in the art will understand that the steps, decisions, and processes embodied in the methods and any corresponding flowcharts described herein may be performed in an order other than that described herein. Thus, the particular flowcharts and descriptions are not intended to limit the associated processes to being performed in the specific order described. 
     It will also be appreciated by those of skill in the art that parts included in one embodiment are interchangeable with other embodiments; one or more parts from a depicted embodiment may be included with other depicted embodiments in any combination. For example, any of the various components described herein and/or depicted in the Figures may be combined, interchanged or excluded from other embodiments. 
     With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art may translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. 
     It will be understood by those within the art that, in general, terms used herein are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). 
     Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” 
     The term “comprising” as used herein is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. 
     All numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of significant digits and ordinary rounding approaches. For example, terms such as about, approximately, substantially, and the like may represent a percentage relative deviation, in various embodiments, of ±1%, ±5%, ±10%, or ±20%. 
     The above description discloses several methods and materials of the present invention. This invention is susceptible to modifications in the methods and materials, as well as alterations in the fabrication methods and equipment. Such modifications will become apparent to those skilled in the art from a consideration of this disclosure or practice of the invention disclosed herein. Consequently, it is not intended that this invention be limited to the specific embodiments disclosed herein, but that it cover all modifications and alternatives corning within the true scope and spirit of the invention as embodied in the attached claims.