Systems, apparatus and methods for stabilizing sacroiliac joints

Abstract

Prostheses and methods are described for stabilizing dysfunctional sacroiliac (SI) joints. The prostheses are sized and configured to be press-fit into surgically created pilot SI joint openings in dysfunctional SI joint structures. The prostheses have a pontoon shape with opposed elongated partially cylindrical sections connected by a bridge section. The bridge section can have various shapes, such as a planar-shaped structure, to accommodate the delivery and / or positioning of a primary or supplemental support member or device between the first and second elongated sections, such as a sacral-alar iliac (S2AI) screw or surgical dowel member.

Description

SYSTEMS, APPARATUS AND METHODS FOR STABILIZING SACROILIAC JOINTSFIELD OF THE INVENTION

[0001] The present invention relates to systems, apparatus and methods for stabilizing diarthrodial synovial joints. More particularly, the present invention relates to systems, apparatus and methods for stabilizing dysfunctional sacroiliac (SI) joints.BACKGROUND OF THE INVENTION

[0002] As is well known in the art, the sacroiliac (SI) joint 6 comprises a diarthrodial synovial joint, which, as illustrated in Fig. 1 A, is defined by the interface between the articular surfaces of the sacrum 2 and the ilium 4.

[0003] As illustrated in Fig. IB, the SI joint 6 generally comprises the shape of an inverted capital letter “L” (denoted “13”), where the long arm of the inverted “L” 15 (i.e., SI joint 6) is oriented along the posterior wall of the pelvis 11 (denoted “25” in Fig. 1 A) and is also oriented relatively straight through its entire course.

[0004] The sacral floor (denoted “21” in Fig. 1C), which is defined by the region between the anterior sacral promontory 19a and the apex 19b of the sacrum 2, generally slopes downward and laterally at an approximately 30% grade relative to the cephalocaudal axis 27.

[0005] As illustrated in Figs. IB and 1C, the short arm of the inverted “L” (denoted “17”) is generally oriented parallel to the transverse plane of the L5-S1 lumbosacral joint and limited superiorly by the sacral ala (denoted “23” in Fig. 1C).

[0006] The apex of the inverted “L” (denoted “29” in Fig. IB) is positioned below the S2 segment region of the sacrum 2 (denoted “S2”) proximate to the S3 segment region of the sacrum 2 (denoted “S3”).

[0007] As illustrated in Fig. ID, the SI joint 6 further comprises a SI joint dorsal recess or gap 7 that is disposed between the sacrum 2 and ilium 4 proximate the S2 segment region of the sacrum 2.

[0008] As is well known in the art, the SI joint further comprises articular cartilage, i.e., hyaline and fibrocartilage, and a strong, extensive ligamentous architecture, which stabilizes the SI joint.

[0009] Generally, the articular surfaces of the sacrum 2 and the ilium 4 that define the SI joint 6 comprise cortical bone 8, which is more compact, dense and hard relative to softertrabecular bone 10, which, as further illustrated in Fig. 1 A, is disposed in the interior regions of the sacrum and ilium 2, 4.

[0010] The SI Joint is distinguished from other synovial joints by the atypical articulation of the different articular surfaces of the sacrum and ilium; the articular surface of the sacrum comprising hyaline cartilage and the articular surface of the ilium comprising substantially stronger fibrocartilage.

[0011] As is further well known in the art, the primary plane of motion of the SI joint is anterior-posterior along a transverse axis. The terms often employed to describe the relative motion of the sacrum and ilium are nutation, which refers to anterior-inferior movement of the sacrum while the coccyx (denoted “3” in Figs. 1A-1D) moves posteriorly relative to the ilium, and counternutation, which refers to posterior-superior movement of the sacrum while the coccyx moves anteriorly relative to the ilium.

[0012] In most healthy individuals, the SI joint range of motion in flexion-extension is approximately 3.0°, approximately 1.5° in axial rotation and approximately 0.8° in lateral bending.

[0013] As is well established, the SI joint performs several seminal biomechanical functions. The primary functions of the SI joint are to attenuate loads exerted on the upper body and to distribute the loads to the lower extremities. The SI joint also functions as a shock absorber for loads exerted on spine.

[0014] As is also well established, the noted loads and, hence, forces exerted on the SI joint can adversely affect the biomechanical functions of the SI joint, which can, and often will, result in SI joint dysfunction - an often-overlooked musculoskeletal pathology associated with lower back pain.

[0015] Indeed, SI joint dysfunction is estimated to be the primary cause of lower back pain in 15-30% of subjects afflicted with such pain. However, lower back pain associated with SI joint dysfunction is suspected to be far more common than most healthcare providers realize, since such pain is often associated with other skeletal and musculoskeletal dysfunctions.

[0016] SI joint dysfunction, and pain associated therewith, can be caused by various SI joint abnormalities and / or disorders, including traumatic fracture dislocation of the pelvis, degenerative arthritis, sacroiliitis, i.e., an inflammation or degenerative condition of thesacroiliac joint; osteitis condensans ilii, and other degenerative conditions of the SI joint structures.

[0017] In some instances, SI joint dysfunction, and pain associated therewith, is caused by a misaligned or dislodged surgical joint implant, such as a surgical pin or dowel, or screw, e.g., a sacral-alar iliac (S2AI) screw.

[0018] Various non-surgical methods, such as administration of pharmacological agents, e.g., the corticosteroid prednisone, and surgical methods and devices, i.e., prostheses, have been developed and employed to treat SI joint dysfunction.

[0019] The most common approach employed to treat SI joint dysfunctions (when non- surgical treatments fail to ameliorate pain associated therewith), at present, is SI joint stabilization, i.e., reinforcing or modulating articulation by and between the sacrum and ilium, via surgical intervention.

[0020] SI joint stabilization typically comprises surgical placement of a prosthesis proximate to or in a dysfunctional SI joint and is generally characterized by the direction of access to the dysfunctional SI joint, i.e., anterior, posterior or lateral trajectory.

[0021] Although several conventional SI joint stabilization surgical methods and associated bone prostheses have effectively ameliorated pain associated with SI joint dysfunction, there remains many disadvantages associated with the conventional methods and associated prostheses.

[0022] A major disadvantage associated with many conventional SI joint stabilization surgical methods is that the surgeon is required to make a substantial incision in and through the skin and tissues of a subject to access the dysfunctional SI joint. Often referred to as “open surgery” methods, these surgical methods have the attendant disadvantages of requiring general anesthesia and often involve increased operative time, pain, hospitalization, and recovery time due to the extensive soft tissue damage. There is also an increased probability of post-surgical complication associated with open surgery methods, such as nosocomial infection.

[0023] Minimally-invasive methods for SI j oint stabilization have thus been developed to address the noted disadvantages associated with open surgery methods. Although conventional minimally-invasive SI joint stabilization methods, such as the methods disclosed in U.S. Pub.No. 2009 / 0076551 to Petersen, have garnered some success in relieving pain associated with SI joint dysfunction and have effectively addressed many of the disadvantages associated with opensurgery methods, there similarly remains many disadvantages associated with conventional minimally-invasive SI joint stabilization methods.

[0024] A major disadvantage associated with many conventional minimally-invasive SI joint stabilization methods is that such methods are difficult to perform and, hence, often require extensive, system-specific surgical training and experience. Despite the level of surgical training and experience that surgeons possess, when such conventional minimally-invasive SI joint stabilization methods are employed, there is still a substantial incidence of damage to the lumbosacral neurovascular structures proximate to the SI joint.

[0025] A further disadvantage associated with many conventional minimally-invasive SI joint stabilization methods and associated apparatus, i.e., prostheses, such as the methods and prostheses disclosed in U.S. Pub. No. 2009 / 0076551 to Petersen, is that pre-existing sacral abnormalities can lead to displacement of the implanted prostheses, which can, and often will result in damage to surrounding bone and soft tissue structures and, hence, post-procedure pain.

[0026] An additional disadvantage associated with many conventional minimally invasive SI joint stabilization methods is that they comprise anterior or lateral trajectories to the dysfunctional SI joint and, hence, muscles, e.g., gluteal aponeurotic fascia and gluteus medius, and ligaments are typically disrupted, and nerves and blood vessels are susceptible to damage during placement of a prosthesis in a dysfunctional SI joint.

[0027] Further, some conventional minimally-invasive SI joint stabilization methods are particularly prone to failure due to displacement of the prostheses in the dysfunctional SI joint and / or failure of the prostheses to effectively engage the SI joint structures, e.g., articular surfaces of the sacrum and / or ilium.

[0028] Various “improved” prostheses have thus been developed for use in minimally- invasive SI joint stabilization methods or procedures to effectively engage SI joint structures and maintain engagement thereto during SI joint function.

[0029] Although many of the “improved” prostheses, when deployed properly in a dysfunctional SI joint, can, and often will, effectively engage SI joint structures, there remains several disadvantages associated with the prostheses. Illustrative are the prostheses disclosed in U.S. Pat. No. 8,951,254 to Mayer, et al.

[0030] The prostheses disclosed in U.S. Pat. No. 8,951,254 comprise or are coated with a liquefiable synthetic polymer that is adapted to liquify upon administration of mechanicalenergy, e.g., high frequency vibration, when implanted and re-solidify thereafter to securely engage the SI joint structures, i.e., sacrum and ilium.

[0031] A major disadvantage associated with the prostheses disclosed in U.S. Pat. No.8,951,254 is that the liquefiable synthetic polymers, when re-solidified in situ, are structurally inferior to the osseous or bone tissue of the sacrum and ilium. The fusion sites between the articular surfaces of the sacrum and ilium that define the SI joint are, thus, highly susceptible to structural fatigue and failure, which can, and often will, result in misalignment of the SI joint and ultimately increased pain for the subject.

[0032] A further disadvantage associated with the prostheses disclosed in U.S. Pat. No.8,951,254 is that the synthetic liquefiable synthetic polymers are also substantially immunogenic and will induce an adverse immune response when the prostheses are implanted in a dysfunctional SI joint. As is well established, the adverse immune response can, and often will, prevent healing and osteogenic processes, e.g., remodeling of damaged osseous tissue and regeneration of new osseous tissue.

[0033] Additional disadvantages associated with the prostheses disclosed in U.S. Pat. No.8,951,254 and many other prostheses designed for minimally-invasive SI joint stabilization are that the noted prostheses are difficult to accurately place in optimum positions in a dysfunctional SI joint and, in many instances, lack sufficient structural properties, such as rigidity and / or fatigue resistance, to effectively stabilize the dysfunctional SI joint.

[0034] It would thus be desirable to provide SI joint stabilization systems, apparatus and methods, which substantially reduce or eliminate the disadvantages associated with conventional SI joint stabilization systems, apparatus and methods.

[0035] It is therefore an object of the invention to provide improved SI joint stabilization systems, apparatus and methods, which substantially reduce or eliminate the disadvantages associated with conventional SI joint stabilization systems, apparatus and methods.

[0036] It is another object of the invention to provide improved minimally-invasive SI joint stabilization systems and apparatus, which can be readily employed to place prostheses in and, thereby, stabilize dysfunctional SI joints via a posterior trajectory.

[0037] It is another object of the invention to provide improved minimally-invasive SI joint stabilization systems, apparatus and methods, which can be readily employed to stabilize dysfunctional SI joints.

[0038] It is another object of the invention to provide improved minimally-invasive SI joint stabilization systems, apparatus and methods, which can readily be employed in minimally- invasive SI joint stabilization procedures to stabilize SI joint structures with misplaced or dislodged prior implants; particularly, surgical pins, dowels or screws.

[0039] It is another object of the invention to provide improved minimally-invasive SI joint stabilization systems, apparatus and methods, which can readily be employed in minimally- invasive SI joint stabilization procedures and provide supplemental stabilization of SI joint structures with prior implants, such as a surgical pin or screw.

[0040] It is another object of the invention to provide improved minimally-invasive SI joint stabilization systems, apparatus and methods, which can readily be employed in conjunction with surgical or orthopedic pins, dowels and screws to provide enhanced stabilization of SI joint structures.

[0041] It is another object of the invention to provide improved minimally-invasive SI joint stabilization systems and apparatus, which, when implanted in a dysfunctional SI joint, effectively ameliorate pain associated with the SI joint dysfunction.

[0042] It is another object of the invention to provide improved SI joint prostheses that can readily be employed in minimally-invasive SI joint stabilization methods and provide secure engagement to SI joint structures.

[0043] It is another object of the invention to provide improved SI joint prostheses that can readily be employed in minimally-invasive SI joint stabilization methods and possess optimal structural properties to effectively stabilize dysfunctional SI joints.

[0044] It is yet another object of the invention to provide improved SI joint prostheses that can readily be employed in minimally-invasive SI joint stabilization methods and facilitate remodeling of damaged osseous tissue and regeneration of new osseous tissue and osseous tissue structures.SUMMARY OF THE INVENTION

[0045] The present invention is directed to minimally-invasive apparatus, systems and methods for stabilizing dysfunctional SI joints.

[0046] In some embodiments of the invention, there are thus provided apparatus (referred to herein as “SI joint prostheses”) for stabilizing dysfunctional SI joints.

[0047] In one embodiment of the invention, a SI joint prosthesis comprises a monolithic member configured and adapted to be advanced into a dysfunctional SI joint in a posterior trajectory, the monolithic member further adapted to transfix and, thereby stabilize the dysfunctional SI joint when the monolithic member is advanced into the dysfunctional SI joint, the monolithic member comprising a first elongated section, a second elongated section and a bridge section, the bridge section disposed between the first elongated section and the second elongated section, the first elongated section configured to be advanced into the sacrum bone structure of the dysfunctional SI joint when the monolithic member is advanced into the dysfunctional SI joint in a posterior trajectory, the first elongated section comprising a first central longitudinal axis, a first open proximal end, a first distal end and a first tapered region disposed on the first distal end to facilitate advancement of the first elongated section into the sacrum bone structure, the second elongated section configured to be advanced into the ilium bone structure of the dysfunctional SI joint when the monolithic member is advanced into the dysfunctional SI joint in the posterior trajectory, the second elongated section comprising a second central longitudinal axis, a second open proximal end, a second distal end and a second tapered region disposed on the second distal end to facilitate the advancement of the second elongated section into the ilium bone structure, the first elongated section and the second elongated section defining a monolithic member plane that extends through the first central longitudinal axis of the first elongated section and the second central longitudinal axis of the second elongated section, the bridge section adapted to be advanced into the intraarticular region of the dysfunctional SI joint when the monolithic member is advanced into the dysfunctional SI joint in the posterior trajectory, wherein the bridge section traverses the sacrum bone structure, the intraarticular region and the ilium bone structure of the dysfunctional SI joint, the bridge section being offset from said monolithic member plane in a vertical direction, the bridge section further comprising a first proximal end, a third distal end and a third tapered region disposed on the third distal end to facilitate the advancement of the bridge section into the intraarticular region of the dysfunctional SI joint.

[0048] In a preferred embodiment, the bridge section and the first and second elongated sections define a monolithic member space between the first and second elongated sections that is sized to receive and / or position a supplemental joint support member or device, such as a surgical pin or screw, therein.

[0049] In some embodiments, the bridge section extends beyond the first interface of the bridge section and the first elongated section and the second interface of the bridge section and the second elongated section in the first vertical direction to further accommodate the receipt and / or positioning of the supplemental joint support member (or device) in the monolithic member space.

[0050] In some embodiments, the bridge section comprises a planar-shaped structure.

[0051] In some embodiments, the bridge section comprises an arched-shaped structure.

[0052] In some embodiments, the bridge section comprises a V-shaped structure.

[0053] In some embodiments, the bridge section comprises a U-shaped structure.

[0054] In another embodiment of the invention, the SI joint prosthesis similarly comprise a monolithic member adapted to be advanced into the dysfunctional SI joint in a posterior trajectory and transfix the dysfunctional SI joint when advanced therein, the monolithic member comprising a first elongated cylindrical shaped section, a second elongated cylindrical shaped section and a bridge section disposed between the first elongated section and the second elongated section, the first elongated cylindrical shaped section similarly configured to be advanced into the sacrum bone structure of the dysfunctional SI joint when the monolithic member is advanced into the dysfunctional SI joint in the posterior trajectory, the first elongated cylindrical shaped section comprising a first open proximal end, a first distal end and a first tapered region disposed on the first distal end, the second elongated cylindrical shaped section similarly configured to be advanced into the ilium bone structure when the monolithic member is advanced into the dysfunctional SI joint in the posterior trajectory, the second elongated cylindrical shaped section comprising a second open proximal end, a second distal end and a second tapered region disposed on the second distal end, the bridge section adapted to be advanced into at least the intraarticular region of the dysfunctional SI joint when the monolithic member is advanced into the dysfunctional SI joint inthe posterior trajectory, wherein the bridge section traverses the sacrum bone structure, the intraarticular region and the ilium bone structure of the dysfunctional SI joint, the bridge section comprising a first proximal end and a third distal end disposed opposite the first proximal end, the bridge section comprising an open bridge structure comprising a top bridge member and a separate bottom bridge member, the top bridge member and the bottom bridge member defining an open region between the top bridge member and the bottom bridge member.

[0055] In a preferred embodiment, the open region of the bridge section is similarly sized to receive and / or position a supplemental joint support member or device, such as a surgical pin or screw, therein.BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Further features and advantages will become apparent from the following and more particular description of the preferred embodiments of the invention, as illustrated in the accompanying drawings, and in which like referenced characters generally refer to the same parts or elements throughout the views, and in which:

[0057] FIGURE 1 A is a schematic illustration of a human pelvic region from an anteroposterior (AP) perspective showing the SI joints thereof;

[0058] FIGURE IB is another schematic illustration of a human pelvic region from a posterior perspective showing the adjoining sacrum and ilium bone structures, and ligamentous structures thereof;

[0059] FIGURE 1C is a schematic illustration of the sacrum and coccyx from a lateral perspective showing the sacral promontory and the articular surface of sacrum;

[0060] FIGURE ID is another schematic illustration of a human pelvic region from a posterior inferior perspective showing the adjoining sacrum and ilium bone structures of an SI joint, and an SI joint dorsal recess between the sacrum and ilium bone structures;

[0061] FIGURE 2A is an illustration of a SI joint from a superior perspective showing the adjoining sacrum and ilium articular surfaces;

[0062] FIGURE 2B is another illustration of a SI joint from a posterior perspective showing the adjoining sacrum and ilium articular surfaces;

[0063] FIGURE 2C is a further illustration of the SI joint shown in FIGURE 2A showing lateral and posterior approaches to the SI joint, in accordance with the invention;

[0064] FIGURE 3 A is a perspective view of one embodiment of a SI joint prosthesis, in accordance with the invention;

[0065] FIGURE 3B is a top plan view of the SI joint prosthesis shown in FIGURE 3A, in accordance with the invention;

[0066] FIGURE 3C is another top plan view of the SI joint prosthesis shown in FIGURE 3A comprising unequal length elongated sections, in accordance with the invention;

[0067] FIGURE 3D is a rear plan view of the SI joint prosthesis shown in FIGURE 3 A, in accordance with the invention;

[0068] FIGURE 3E is a front plan view of the SI joint prosthesis shown in FIGURE 3 A, in accordance with the invention;

[0069] FIGURE 3F is a rear perspective view of the SI joint prosthesis shown in FIGURE3A, in accordance with the invention;

[0070] FIGURE 3G is a front perspective view of the SI joint prosthesis shown in FIGURE 3A, in accordance with the invention;

[0071] FIGURE 3H is a right-side plan view of the SI joint prosthesis shown in FIGURE 3A, in accordance with the invention;

[0072] FIGURE 31 is a right-side sectional plan view of the SI joint prosthesis shown in FIGURE 3A, in accordance with the invention;

[0073] FIGURE 3J is another rear perspective view of the SI joint prosthesis shown in FIGURE 3A comprising a proximal bridge opening, in accordance with the invention;

[0074] FIGURE 3K is another rear plan view of the SI joint prosthesis shown in FIGURE 3A showing the cross-sectional shape defined by the outer surface of the prosthesis, in accordance with the invention;

[0075] FIGURE 4A is an illustration of the SI joint prosthesis shown in FIGURE 3 A disposed in a post-prosthesis insertion SI joint opening, in accordance with the invention;

[0076] FIGURE 4B is an illustration of the post-prosthesis insertion SI joint opening generated or induced when the SI joint prosthesis shown in FIGURE 3 A is inserted in a pilot SI joint opening, in accordance with the invention;

[0077] FIGURE 5 A is a top perspective view of an embodiment of a SI joint prosthesis having an offset, arched or radius-shaped bridge section, in accordance with the invention;

[0078] FIGURE 5B is a front perspective view of the SI joint prosthesis shown in FIGURE 5A, in accordance with the invention;

[0079] FIGURE 5C is a rear plan view of the SI joint prosthesis shown in FIGURE 5A, in accordance with the invention;

[0080] FIGURE 6A is a top perspective view of an embodiment of a SI joint prosthesis having an offset V-shaped bridge section, in accordance with the invention;

[0081] FIGURE 6B is a front perspective view of the SI joint prosthesis shown in FIGURE 6A, in accordance with the invention;

[0082] FIGURE 6C is a rear plan view of the SI joint prosthesis shown in FIGURE 6A, in accordance with the invention;

[0083] FIGURE 7A is a top perspective view of an embodiment of a SI joint prosthesis having an offset U-shaped bridge section, in accordance with the invention;

[0084] FIGURE 7B is a front perspective view of the SI joint prosthesis shown in FIGURE 7A, in accordance with the invention;

[0085] FIGURE 7C is a rear plan view of the SI joint prosthesis shown in FIGURE 7A, in accordance with the invention;

[0086] FIGURE 8A is a top perspective view of an embodiment of a SI joint prosthesis having an offset planar-shaped bridge section, in accordance with the invention;

[0087] FIGURE 8B is a front perspective view of the SI joint prosthesis shown in FIGURE 8A, in accordance with the invention;

[0088] FIGURE 8C is an rear plan view of the SI joint prosthesis shown in FIGURE 8A, in accordance with the invention;

[0089] FIGURE 9A is a top perspective view of an embodiment of a SI joint prosthesis having ovate or arcuate-shaped open bridge section, in accordance with the invention;

[0090] FIGURE 9B is a front perspective view of the SI joint prosthesis shown in FIGURE 9A, in accordance with the invention;

[0091] FIGURE 9C is a front plan view of the SI joint prosthesis shown in FIGURE 9A, in accordance with the invention;

[0092] FIGURE 9D is a further front plan view of the SI joint prosthesis shown in FIGURE 9A, in accordance with the invention;

[0093] FIGURE 10A is a top perspective view of an embodiment of a SI joint prosthesis having open bridge section comprising opposing V-shaped top and bottom members, in accordance with the invention;

[0094] FIGURE 10B is a front perspective view of the SI joint prosthesis shown in FIGURE 10A, in accordance with the invention;

[0095] FIGURE 10C is a front plan view of the SI joint prosthesis shown in FIGURE 10A, in accordance with the invention;

[0096] FIGURE 10D is a further front plan view of the SI joint prosthesis shown in FIGURE 10A, in accordance with the invention;

[0097] FIGURE 11A is a top perspective view of an embodiment of a SI joint prosthesis having an open bridge section comprising opposing U-shaped top and bottom members, in accordance with the invention;

[0098] FIGURE 1 IB is a front perspective view of the SI joint prosthesis shown in FIGURE 11 A, in accordance with the invention;

[0099] FIGURE 11C is a front plan view of the SI joint prosthesis shown in FIGURE 11A, in accordance with the invention;[000100] FIGURE 1 ID is a further front plan view of the SI joint prosthesis shown in FIGURE 11 A, in accordance with the invention;[000101] FIGURE 12A is a top perspective view of an embodiment of a SI joint prosthesis having an open bridge section comprising opposing planar top and bottom members, in accordance with the invention;[000102] FIGURE 12B is a front perspective view of the SI joint prosthesis shown in FIGURE 12A, in accordance with the invention;[000103] FIGURE 12C is a front plan view of the SI joint prosthesis shown in FIGURE 12A, in accordance with the invention;[000104] FIGURE 12D is a further front plan view of the SI joint prosthesis shown in FIGURE 12A, in accordance with the invention;[000105] FIGURE 13 is an illustration of the SI joint prosthesis shown in FIGURE 5A with a surgical implant, i.e., surgical dowel, disposed between the elongated sections thereof, in accordance with the invention;[000106] FIGURE 14 is an illustration of the SI joint prosthesis shown in FIGURE 9A with a surgical implant, i.e., orthopedic screw, disposed between the elongated sections thereof, in accordance with the invention;[000107] FIGURE 15 is a CT scan of a SI joint from a posterior perspective with a surgical dowel implanted therein;[000108] FIGURE 16A is a perspective view of one embodiment of drill guide assembly, in accordance with the invention;[000109] FIGURE 16B is a perspective view the access sleeve of the drill guide assembly shown in FIGURE 16A, in accordance with the invention;[000110] FIGURE 16C is a partial section, front sectional plan view of the access sleeve shown in FIGURE 16B, in accordance with the invention;[000111] FIGURE 16D is a right-side plan view of the access sleeve shown in FIGURE 16B, in accordance with the invention;[000112] FIGURE 16E is a perspective view of one embodiment of an access sleeve handle that is configured to engage the access sleeve shown in FIGURE 16B, in accordance with the invention;[000113] FIGURE 16F is an end plan view of the access sleeve handle shown in FIGURE 16E, in accordance with the invention;[000114] FIGURE 16G is a perspective view of the drill guide of the drill guide assembly shown in FIGURE 16A, in accordance with the invention;[000115] FIGURE 16H is a front plan view of the drill guide shown in FIGURE 16G, in accordance with the invention;[000116] FIGURE 161 is a top plan view of the drill guide shown in FIGURE 16G, in accordance with the invention;[000117] FIGURE 16J is a bottom plan view of the drill guide shown in FIGURE 16G, in accordance with the invention;[000118] FIGURE 16K is a perspective view of the guide pin of the drill guide assembly shown in FIGURE 16A, in accordance with the invention;[000119] FIGURE 16E is a perspective view of the bone dislodging apparatus, i.e., drill bit, shown in FIGURE 16A, in accordance with the invention;[000120] FIGURE 17A is a further illustration of the SI joint shown in FIGURE 2B showing one embodiment of a pilot SI joint opening, in accordance with the invention;[000121] FIGURE 17B is a further illustration of the embodiment of the SI joint opening shown in FIGURE 17A, in accordance with the invention;[000122] FIGURE 18A is a perspective view of one embodiment of a prosthesis deployment assembly, in accordance with the invention;[000123] FIGURE 18B is a front plan view of the prosthesis deployment assembly shown in FIGURE 18A, in accordance with the invention;[000124] FIGURE 18C is a left side plan view of the prosthesis deployment assembly shown in FIGURE 18A, in accordance with the invention;[000125] FIGURE 18D is a top plan view of the prosthesis deployment assembly shown in FIGURE 18A, in accordance with the invention;[000126] FIGURE 18E is a bottom plan view of the prosthesis deployment assembly shown in FIGURE 18A, in accordance with the invention;[000127] FIGURE 18F is a front plan view of a prosthesis engagement rod of the prosthesis deployment assembly shown in FIGURE 18A, in accordance with the invention;[000128] FIGURE 18G is a front plan view of the prosthesis deployment assembly shown in FIGURE 18A engaged to a SI joint prosthesis of the invention, in accordance with the invention;[000129] FIGURE 19A is a perspective view of one embodiment of a prosthesis extraction assembly, in accordance with the invention;[000130] FIGURE 19B is a front plan sectional view of the prosthesis extraction rod of the prosthesis extraction assembly shown in FIGURE 19A, in accordance with the invention;[000131] FIGURE 19C is a partial section, front sectional plan view of the threaded end of the prosthesis extraction rod shown in FIGURE 19B, in accordance with the invention;[000132] FIGURE 19D is a perspective view of the extraction fork of the prosthesis extraction assembly shown in FIGURE 19A, in accordance with the invention;[000133] FIGURE 19E is a front plan view of the extraction fork shown in FIGURE 19D, in accordance with the invention;[000134] FIGURE 19F is a top plan view of the extraction fork shown in FIGURE 19D, in accordance with the invention; and[000135] FIGURE 19G is an exploded view of the slap hammer assembly of the prosthesis extraction assembly shown in FIGURE 19A, in accordance with the invention.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT[000136] Before describing the present invention in detail, it is to be understood that this invention is not limited to particularly exemplified apparatus, systems, structures or methods as such may, of course, vary. Thus, although a number of apparatus, systems, structures and methods similar or equivalent to those described herein can be used in the practice of the present invention, the preferred apparatus, systems, structures and methods are described herein.[000137] It is also to be understood that, although the present invention is described and illustrated in connection with sacroiliac (SI) joint stabilization, fixation and fusion procedures, the invention is not limited to such procedures. According to the invention, the apparatus, systems, structures and methods of the invention can also be employed to stabilize and / or fuse other articulating bone structures, including, without limitation, spinal vertebrae, tarsal bones and the like.[000138] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting. [000139] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one having ordinary skill in the art to which the invention pertains.[000140] Further, all publications, patents and patent applications cited herein, whether supra or infra, are hereby incorporated by reference in their entirety.[000141] As used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to “an incision” includes two or more incisions and the like.[000142] Further, ranges can be expressed herein as from “about” or “approximately” one particular value, and / or to “about” or “approximately” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about” or “approximately”, it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.[000143] It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” or “approximately” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “approximately 10” is also disclosed. It is also understood that when a value is disclosed that “less than or equal to” the value, “greater than or equal to the value” and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value “10” is disclosed then “less than or equal to 10” as well as “greater than or equal to 10” is also disclosed.Definitions[000144] The terms “sacroiliac joint”, “SI joint”, “sacroiliac junction” and “SI junction” are used interchangeably herein, and mean and include any region proximate to articulating regions of the sacrum and ilium bone structures and, hence, a junction between and defined by sacrum and ilium bone structures.[000145] The term “dysfunctional” as used in connection with a SI joint, means and includes a physiological abnormality, disorder or impairment of an SI joint, including, but limited to, traumatic fracture dislocation of the pelvis, degenerative arthritis, sacroiliitis, i.e., an inflammation or degenerative condition of the SI joint; osteitis condensans ilii, and other degenerative conditions of SI joint bone structures.[000146] The terms “articular surface” and “articulating surface” are used interchangeably herein in connection with bone structures; particularly, the sacrum and ilium bone structures of a SI joint, and mean and include a surface of a bone structure that forms an articulating junction (i.e., a synovial joint) with an adjacent bone structure, e.g., the articular surfaces of the sacrum and ilium bone structures.[000147] The terms “fusion” and “arthrodesis” are used interchangeably herein in connection with bone structures, and mean and include partial or complete immobilization of adjacent bone structures; particularly, the sacrum and ilium bone structures of a SI joint.[000148] The term “stabilization”, as used herein, means and includes reinforcing, e.g., supporting, or modulating motion of adjacent articular bone structures; particularly, the sacrum and ilium bone structures of a SI joint. The term “stabilization”, thus, in some instances, means and includes fusion and arthrodesis of adjacent bone structures.[000149] The term “transfix”, as used herein in connection with a SI joint, means and includes stabilization of the SI joint via advancement of a prosthesis of the invention into the SI jointand / or the position of the prosthesis after being advanced into the SI joint, wherein the prosthesis intersects (i.e., passes through) the axial and sagittal plans of the ilium and sacrum bone structures of the SI joint, whereby the SI joint is rendered motionless along its longitudinal axis. [000150] The terms “prosthesis” and “SI joint prosthesis” are used interchangeably herein, and mean and include an apparatus or system configured and adapted to stabilize or modulate motion of articulating bone structures; particularly, the sacrum and ilium bone structures of a SI joint. [000151] The term “biodegradable”, as used herein, means the ability of a material; particularly, a polymer or adhesive, to breakdown and be absorbed within the physiological environment of a SI joint and / or a structure associated therewith, including sacrum and ilium bone structures, by one or more physical, chemical, or cellular processes.[000152] Biodegradable polymers, according to the invention, thus include, without limitation, polylactide polymers (PLA), copolymers of lactic and glycolic acids, including poly(lactic-co- glycolic) acid (PLGA) and poly(s-caprolactone-co-L-lactic) acid (PCL-LA); glycine / PLA copolymers, polyethylene oxide (PEO) / PLA block copolymers, acetylated polyvinyl alcohol (PVA) / polycaprolactone copolymers, poly(glycerol sebacate) (PGS) and its derivatives, including poly(glycerol-co-sebacate acrylate) (PGSA); poly(polyol sebacate) (PPS), poly(xylitol sebacate) (PXS), poly(xylitol glutamate sebacate) (PXGS), hydroxybutyrate-hydroxy valerate copolymers, polyesters such as, but not limited to, aspartic acid and different aliphatic diols; poly(alkylene tartrates) and their copolymers with polyurethanes, polyglutamates with various ester contents and with chemically or enzymatically degradable bonds, other biodegradable nonpeptidic polyamides, amino acid polymers, polyanhydride drug carriers such as, but not limited to, poly(sebacic acid) (PSA); aliphatic-aromatic homopolymers, and poly(anhydride-co- imides), poly(phosphoesters) by matrix or pendant delivery systems, poly(phosphazenes), poly(iminocarbonate), crosslinked poly(ortho ester), hydroxylated polyester-urethanes, or the like.[000153] Biodegradable adhesives, according to the invention, thus include, without limitation, poly(glycerol-co-sebacate acrylate) (PGSA), poly(L-glutamic acid)-based compositions, poly(y- glutamic acid)-based compositions, poly(alkyl cyano acrylate)-based compositions, polyacrylic acid-based compositions, including polyacrylic acid crosslinked with pentaerythritol and / or allyl sucrose, polyacrylic acid crosslinked with divinyl glycol, and combinations thereof; fibrin-based compositions, collagen-based compositions, including collagen / poly(L-glutamic acid)compositions; albumin-based compositions, including BioGlue® (comprises purified bovine serum albumin (BSA) and glutaraldehyde); cyanoacrylate compositions, including butyl-2- cyanoacrylate adhesives (e.g., Indermil®, Histoacryl®, Histoacryl® Blue, and LiquiBand®) and octyl-2-cyanoacrylate adhesives (e.g., Dermabond®, SurgiSeal™, LiquiBand® Flex, and OctylSeal); polyethylene glycol) (PEG) based compositions, including FocalSeal®, Progel™, Duraseal™, DuraSeal™ Xact, Coseal® and ReSure Sealant; polysaccharide-based compositions, polypeptide-based compositions, and combinations thereof.[000154] The term “osteogenic composition”, as used herein, means and includes an agent or composition that induces or modulates an osteogenic physiological or biological process, or cellular activity, e.g., induces proliferation, and / or growth and / or remodeling and / or regeneration of bone or osseous tissue.[000155] The term “osteogenic composition” thus means and includes, without limitation, the following osteogenic materials and compositions comprising same: demineralized bone matrix, autograft bone material, allograft bone material, xenograft bone material, polymethylmethacrylate, calcium-based bone void filler material, including hydroxyapatite (HA) and tricalcium phosphate; and combinations or mixtures thereof.[000156] The term “osteogenic composition” also means and includes, without limitation, the following polymer materials and compositions comprising same: poly(glycerol sebacate) (PGS), poly(glycerol-co-sebacate) acrylate (PGSA) and co-polymers, such as poly(glycerol sebacate)- co-poly(ethylene glycol) (PGS-PEG); and / or composites thereof, e.g., PGS-hydroxyapatite (HA) composites and PGS-poly(s-caprolactone) (PGS-PCL) composites.[000157] The term “osteogenic composition” also means and includes, without limitation, acellular extracellular matrix (ECM) derived from mammalian tissue sources.[000158] The term “osteogenic composition” thus means and includes, without limitation, acellular ECM derived from bone or osseous tissue, small intestine submucosa (SIS), epithelium of mesodermal origin, i.e., mesothelial tissue, placental tissue, omentum tissue, and combinations thereof.[000159] The terms “biologically active agent” and “biologically active composition” are used interchangeably herein, and mean and include agent or composition that induces or modulates a physiological or biological process, or cellular activity, e.g., induces proliferation, and / or growth and / or regeneration of tissue, including osseous tissue.[000160] The terms “biologically active agent” and “biologically active composition”, as used herein, thus include agents and compositions that can be varied in kind or amount to provide a therapeutic level effective to mediate the formation or healing of osseous tissue, cartilage and connective tissue, e.g., tendons and ligaments. The term “biologically active composition”, in some instances, thus means and includes an “osteogenic composition.”[000161] The terms “biologically active agent” and “biologically active composition” thus mean and include, without limitation, the following bone morphogenic proteins (BMPs) and compositions comprising same: BMP-1, BMP2a, BMP2b, BMP3, BMP4, BMP5, BMP6, BMP7 (also referred to as osteogenic protein 1 (OP-1)) and BMP8a.[000162] The terms “biologically active agent” and “biologically active composition” also mean and include, without limitation, the following biological agents and compositions comprising same: platelet derived growth factor (PDGF), an insulin-like growth factor (IGF), including IGF-1 and IGF-2; basic fibroblast growth factor (bFGF) (also referred to as FGF2), transforming growth factor-0 (TGF-0), including, TGF-01 and TGF-02; a growth hormone (GH), parathyroid hormone (PTH, including PTH1-34), transforming growth factor-a (TGF-a), granulocyte / macrophage colony stimulating factor (GM-CSF), epidermal growth factor (EGF), growth and differentiation factor-5 (GDF-5), vascular endothelial growth factor (VEGF), angiogenin, angiopoietin-1, del-1, follistatin, granulocyte colony-stimulating factor (G-CSF), hepatocyte growth factor / scatter factor (HGF / SF), interleukin-8 (IL-8), interleukin- 10 (IL-10), leptin, midkine, placental growth factor, platelet-derived endothelial cell growth factor (PD- ECGF), platelet-derived growth factor-BB (PDGF-BB), pleiotrophin (PTN), progranulin, proliferin, a matrix metalloproteinase (MMP), angiopoietin 1 (angl), angiopoietin 2 (ang2) and delta-like ligand 4 (DLL4).[000163] The terms “biologically active agent” and “biologically active composition” also mean and include, without limitation, the following cells and compositions comprising same: bone marrow-derived progenitor cells, bone marrow stromal cells (BMSCs), osteoprogenitor cells, osteoblasts, osteocytes, osteoclasts, committed or partially committed cells from the osteogenic or chondrogenic lineage, hematopoietic stem cells, chondrocytes, chondrogenic progenitor cells (CPCs), mesenchymal stem cells (MSCs) and embryonic stem cells.[000164] The terms “biologically active agent” and “biologically active composition” also mean and include an “extracellular vesicle (EV)”, “exosome”, “microsome” or “micro-vesicle”,which are used interchangeably herein, and mean and include a biological structure formed from a hydrocarbon monolayer or bilayer configured to contain or encase a composition of matter.[000165] The terms “extracellular vesicle (EV)”, “exosome”, “microsome” and “micro-vesicle” thus include, without limitation, a biological structure formed from a lipid layer configured to contain or encase biologically active agents and / or combinations thereof.[000166] The terms “extracellular vesicle (EV)”, “exosome”, “microsome” and “micro-vesicle” also include, without limitation, EVs derived from the aforementioned cells and compositions comprising same, e.g., BMSC-derived EVs.[000167] The terms “pharmacological agent” and “active agent” are used interchangeably herein, and mean and include an agent, drug, compound, composition or mixture thereof, including its formulation, which provides some therapeutic, often beneficial, effect. This includes any physiologically or pharmacologically active substance (or composition comprising same) that produces a localized or systemic effect or effects in animals, including warm blooded mammals.[000168] The terms “pharmacological agent” and “active agent” thus mean and include, without limitation, the following osteoinductive agents and compositions comprising same: icaritin, tumor necrosis factor alpha (TNF-a) inhibitors, including etanercept and infliximab, disease-modifying anti-rheumatic drugs (DMARDs), including methotrexate and hydroxychloroquine, antibiotics, anti-viral agents, steroidal anti-inflammatories, non-steroidal anti-inflammatories, anti -thrombotic agents, including anti -coagulants and anti-platelet agents, and vasodilating agents.[000169] The terms “pharmacological agent” and “active agent” further mean and include, without limitation, the following bisphosphonate agents and compositions comprising same: risedronate (Actonel®), alendronate (Fosamax®), ibandronate (Boniva®), zoledronic acid (Reclast®), pamidronate (Aredia®) and etidronate (Didronel®).[000170] The terms “pharmacological agent” and “active agent” further mean and include, without limitation, the following antibiotics and compositions comprising same: penicillin, carboxypenicillins, such as ticarcillin; tetracyclines, such as minocycline; gentamicin, vancomycin, ciprofloxacin, amikacin, aminoglycosides, cephalosporins, clindamycin, erythromycin, fluoroquinolones, macrolides, azolides, metronidazole, trimethoprimsulfamethoxazole, polymyxin B, oxytetracycline, tobramycin, cefazolin and rifampin.[000171] The terms “anti-inflammatory” and “anti-inflammatory agent” are also used interchangeably herein, and mean and include a “pharmacological agent”, which, when a therapeutically effective amount is administered to a subject, prevents or treats bodily tissue inflammation, i.e., the protective tissue response to injury or destruction of tissues, which serves to destroy, dilute, or wall off both the injurious agent and the injured tissues.[000172] Anti-inflammatory agents thus include, without limitation, dexamethasone, betamethasone, prednisone, prednisolone, methylprednisolone sodium succinate, methylprednisolone, cortisone, ketorolac, diclofenac and ibuprofen.[000173] The terms “pharmacological agent” and “active agent” further mean and include, without limitation, the following metal -based antimicrobials and compositions comprising same: silver particles, copper particles, cobalt particles, nickel particles, zinc particles, zirconium particles, molybdenum particles, lead particles and mixtures thereof.[000174] As indicated above, the term “pharmacological composition”, as used herein, means and includes a composition comprising a “pharmacological agent” and “active agent”.[000175] The term “therapeutically effective”, as used herein, means that the amount of the “pharmacological agent” and / or “pharmacological composition” and / or “biologically active agent” and / or “biologically active composition” administered is of sufficient quantity to ameliorate one or more causes, symptoms, or sequelae of a disease or disorder. Such amelioration only requires a reduction or alteration, not necessarily elimination, of the cause, symptom, or sequelae of a disease or disorder.[000176] The terms “patient” and “subject” are used interchangeably herein, and mean and include warm blooded mammals, humans and primates; avians; domestic household or farm animals, such as cats, dogs, sheep, goats, cattle, horses and pigs; laboratory animals, such as mice, rats and guinea pigs; fish; reptiles; zoo and wild animals; and the like.[000177] The terms “one embodiment”, “one aspect”, and “an embodiment” and “an aspect”, as used herein, mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment and not that any particular embodiment is required to have a particular feature, structure or characteristic described herein unless set forth in the claim.[000178] The phrase “in one embodiment” or similar phrases employed herein do not limit the inclusion of a particular element of the invention to a single embodiment. The element may thus be included in other, or all embodiments discussed herein.[000179] The term “substantially”, as used herein, means and includes the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result to function as indicated. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context, such that enclosing nearly all the length of a lumen would be substantially enclosed, even if the distal end of the structure enclosing the lumen had a slit or channel formed along a portion thereof.[000180] Use of the term “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, structure which is “substantially free of’ a bottom would either completely lack a bottom or so nearly completely lack a bottom that the effect would be effectively the same as if it completely lacked a bottom.[000181] The term “comprise” and variations of the term, such as “comprising” and “comprises,” means “including, but not limited to” and is not intended to exclude, for example, other components, elements or steps.[000182] The following disclosure is provided to further explain in an enabling fashion the best modes of performing one or more embodiments of the present invention. The disclosure is further offered to enhance the understanding and appreciation for the inventive principles and advantages thereof, rather than to limit in any manner the invention. The invention is defined solely by the appended claims, including any amendments made during the pendency of this application, and all equivalents of those claims as issued.[000183] As indicated above, the present invention is directed to minimally-invasive methods, systems and apparatus for stabilizing dysfunctional SI joints.[000184] In some embodiments of the invention, there are thus provided minimally-invasive systems for stabilizing dysfunctional SI joints. As indicated above, in a preferred embodiment, the minimally-invasive systems (also referred to herein as “minimally-invasive SI jointstabilization systems”) can be readily employed in minimally -invasive methods or procedures to stabilize dysfunctional SI joints via a posterior trajectory.[000185] In some embodiments of the invention, there are also provided apparatus, i.e., SI joint prostheses, that can be readily employed in minimally-invasive procedures to stabilize dysfunctional SI joints; particularly, dysfunctional SI joints with misaligned or dislodged prior implants, such as surgical pins, dowels and / or screws.[000186] As discussed in detail herein, the apparatus can also be readily employed in minimally-invasive procedures to provide supplemental stabilization of SI joint structures with prior implants, such as a surgical dowel shown in Figs. 13 and 15 (and denoted “SD”).[000187] According to the invention, the apparatus can also be readily employed in conjunction with surgical or orthopedic pins, dowels and screws to provide enhanced stabilization of SI joint structures.[000188] As also discussed in detail herein, the apparatus are specifically configured and adapted to be advanced into SI joints in a posterior trajectory, whereby the apparatus transfix the SI joint.[000189] As indicated above, SI joint stabilization, including minimally-invasive SI joint stabilization, typically comprises surgical placement of a prosthesis proximate to or in a dysfunctional SI joint in anterior, lateral and posterior trajectories.[000190] From the perspective of Fig. 1A, an anterior trajectory to the SI joint 6 (and, hence, dysfunctional SI joint) would be substantially perpendicular to the page upon which Fig. 1A is printed.[000191] Referring to Fig. IB, a lateral trajectory to the SI joint 6 is denoted by arrow “A”. [000192] Referring now to Fig. 2A, there is shown a close-up illustration of a portion of the leftmost SI joint 6 illustrated in Fig. 1A. For illustrative simplicity, a uniform layer of cortical bone 8 is shown adjacent to a deeper layer of trabecular bone 10 on both of the depicted sacrum 2 and ilium 4 portions.[000193] Referring now to Fig. 2B, there is shown a view of the same structure from a different posterior perspective. From the perspective of Fig. 2B, a posterior trajectory to the SI joint 6 would be substantially perpendicular to the page upon which Fig. 2B is printed. Indeed, referring to Fig. 2C, a variation similar to that depicted in Fig. 2A is illustrated, showing an approximate approach vector for a lateral trajectory to the SI joint 6 versus a posterior trajectory,using the orientation paradigms introduced in Figs. 1A and 2A-2C. Such paradigms are used to illustrate various embodiments of the subject invention in various figures that follow Figs. 1A and 2A-2C.[000194] As indicated above, a major disadvantage associated with many conventional SI joint stabilization methods that employ anterior or lateral surgical placement trajectories is that muscles and ligaments proximate the dysfunctional SI joint are typically disrupted and often damaged by a prosthesis. Nerves and blood vessels proximate the dysfunctional SI joint are also susceptible to damage during such SI joint stabilization methods.[000195] In contrast, a posterior trajectory (or advancement); particularly, an inferior-posterior trajectory (which is shown in Fig. 1C and denoted by arrow “B”), of SI joint prostheses of the invention to a dysfunctional SI joint is much less invasive than anterior or lateral surgical placements. Indeed, less tissue and fewer muscles proximate the dysfunctional SI joint are disrupted, and nerves and large blood vessels are avoided. The SI joint prostheses, when advanced into a dysfunctional SI joint, are also transfixed to optimal regions of cortical bone proximate the dysfunctional SI joint and, thereby, provide superior arthrodesis of the dysfunctional SI joint.[000196] In a preferred embodiment of the invention, the systems for stabilizing a dysfunctional SI joint comprise (i) a prosthesis (referred to herein as a “SI joint prosthesis”) configured and adapted to be advanced into a dysfunctional SI joint and stabilize the dysfunctional SI joint when positioned therein, (ii) a drill guide assembly configured and adapted to access the dysfunctional SI joint via a posterior trajectory and create at least one predetermined opening in the dysfunctional SI joint (referred to hereinafter as a “pilot SI joint opening”) to facilitate advancement of a SI joint prosthesis therein, (iii) a prosthesis deployment assembly configured and adapted to engage a SI joint prosthesis and advance the SI joint prosthesis into the pilot SI joint opening and, thereby, dysfunctional SI joint, and (iv) a prosthesis extraction assembly adapted to engage and remove a SI joint prosthesis from a SI joint.[000197] The SI joint prostheses, drill guide assemblies, and preferred prosthesis deployment and extraction assemblies of the invention will now be described in detail.SI Joint Prostheses[000198] As discussed in detail below, various SI joint prostheses are configured and adapted and, hence, capable of advancement into dysfunctional SI joints in a posterior trajectory,whereby the SI joint prosthesis stabilizes the dysfunctional SI joint.[000199] Referring now to Figs. 3A and 3B, there is illustrated one embodiment of a SI joint prosthesis of the invention that is particularly suitable for advancement into dysfunctional SI joints in a posterior trajectory, e.g., an inferior-posterior trajectory. As illustrated in Figs. 3A and 3B, the SI joint prosthesis 70a comprises an elongated implantable member comprising proximal and distal ends 72, 74, and first and second elongated partially cylindrical sections 76a, 76b connected to a bridge section (also referred to herein as “an osteotome”) 78a, whereby the prosthesis 70a comprises a continuous exterior surface comprising first and second partially cylindrical surface regions 77a, 77b.[000200] As illustrated in Figs. 3F and 3G, the first and second elongated partially cylindrical sections 76a, 76b comprise proximal and distal ends 79a, 79b. The bridge section 78a similarly comprises proximal and distal ends 81a, 81b.[000201] According to the invention, the SI joint prosthesis 70a can comprise any suitable length from the proximal ends 79a to the distal ends 79b of the elongated partially cylindrical sections 76a, 76b. In some embodiments, the SI joint prosthesis 70a comprises a length in the range of 20.0 - 50.0 mm, more preferably, a length in the range of 30.0 - 40.0 mm.[000202] According to the invention, the first and second elongated partially cylindrical sections 76a, 76b of the SI joint prosthesis 70a can comprise the same length or different lengths, e g., the second elongated partially cylindrical section 76b comprises a greater length than the first elongated partially cylindrical section 76a, such as illustrated in Fig. 3C.[000203] As illustrated in Figs. 3D, 3E, 17A and 17B the first partially cylindrical surface region 77a preferably comprises a partially cylindrical surface region shape that corresponds to at least a portion of the first lobe region (or sacrum opening) 103 of a pilot SI joint opening 100 and / or the second lobe region (or ilium opening) 104 of the pilot SI joint opening 100, created by a drill guide assembly of the invention, depending on the entry position of the SI loint prosthesis 70a into the pilot SI joint opening 100.[000204] The second partially cylindrical surface region 77b similarly preferably comprises a partially cylindrical surface region shape that corresponds to at least a portion of the first lobe region (or sacrum opening) 103 of the pilot SI joint opening 100 and / or the second lobe region (or ilium opening) 104 of the pilot SI joint opening 100, again depending on the entry position of the SI Joint prosthesis 70a into the pilot SI joint opening 100.[000205] Referring now to Fig. 3K, according to the invention, the continuous exterior surface of the SI Joint prosthesis 70a defines a prosthesis cross-sectional shape (denoted “Pcss”) having a longitudinal axis LA3.[000206] In some embodiments of the invention, the length of the prosthesis cross-sectional shape Pecs along longitudinal axis LA3 is greater than the length of a pilot SI joint opening of the invention, such as pilot SI joint opening 100, i.e., cross-sectional shape thereof, whereby, when the SI joint prosthesis 70a is inserted into pilot SI joint opening 100, as shown in Fig. 4A, the pilot SI opening 100 transitions to a post-prosthesis insertion SI joint opening 200 comprising a larger cross-sectional length shape that corresponds to the length of the prosthesis cross-sectional shape Pecs, as shown in Fig. 4B.[000207] As also illustrated in Fig. 4B, in a preferred embodiment, the cross-sectional area of the sacrum opening 203 of the post-prosthesis insertion SI joint opening 200 also comprises a cross-sectional area (denoted “A2-3”) that is greater than the cross-sectional area A2i-1 of the sacrum opening 103 of the SI joint opening 100 illustrated in Fig. 17A, and the ilium opening 104 of the post-prosthesis insertion SI joint opening 200 comprises a cross-sectional area (denoted “A2-4”) that is greater than the cross-sectional area A2i-2 of the ilium opening 104 of the SI joint opening 100 illustrated in Fig. 17 A.[000208] In a preferred embodiment, when SI joint prosthesis 70a is advanced into a dysfunctional SI joint, as described above, the prosthesis 70a transfixes and, thereby, stabilizes the dysfunctional SI joint.[000209] As further illustrated in Fig. 4B, the post-prosthesis insertion SI joint opening 200 also comprises a noncircular region (denoted “205”), which is achieved by virtue of the tapered bridge or osteotome 78a of the SI joint prosthesis 70a cutting into and through the articular cartilage and cortical bone 8, which define a SI joint, and the trabecular bone 10 proximate the SI joint.[000210] In a preferred embodiment of the invention, to achieve sufficient expansion of the pilot SI joint openings of the invention; particularly, pilot SI joint opening 100, when the SI joint prosthesis 70a (and prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i, described below) is inserted therein, preferably, the cross-sectional areas of the regions defined by the first and second elongated partially cylindrical sections 76a, 76b of the SI joint prosthesis 70a (and prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i) are at least 0.05% greater than the cross-sectional areas defined by the first and second lobe regions 103, 104 of the pilot SI joint opening 100, and the cross-sectional areas defined by the sacrum and ilium guide portions 103, 104 of pilot SI joint opening 100.[000211] In some embodiments of the invention, the cross-sectional areas of the regions defined by the first and second elongated partially cylindrical sections 76a, 76b of the SI joint prosthesis 70a (and prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i) are substantially equal to or slightly smaller, e.g., < 0.05%, than the cross-sectional areas defined by the first and second lobe regions 103, 104 of the pilot SI joint opening 100.[000212] Referring back to Fig. 3 A, in a preferred embodiment, the distal ends 79b of the first and second elongated partially cylindrical sections 76a, 76b comprise tapered regions 84a, 84b, which facilitate (i) insertion of the distal ends 79b of the first and second elongated partially cylindrical sections 76a, 76b into the first and second lobe regions 103, 104 of the pilot SI joint opening 100 and (ii) as discussed above, in some embodiments, transition of the pilot SI joint opening 100 from a first configuration and size to a second expanded configuration and size, as shown in Fig. 4B, when the SI joint prosthesis 70a is inserted therein.[000213] As illustrated in Fig. 3F, in a preferred embodiment, the first elongated partially cylindrical section 76a of the SI joint prosthesis 70a comprises an internal prosthesis lumen 86a that extends from the proximal end 79a of the first elongated partially cylindrical section 76a, and the second elongated partially cylindrical section 76b of the SI joint prosthesis 70a also comprises an internal prosthesis lumen 86b that extends from the proximal end 79a of the second elongated partially cylindrical section 76b.[000214] In a preferred embodiment, the internal prosthesis lumens 86a, 86b of the SI joint prosthesis 70a are sized and configured to receive the prosthesis guide pin 656 and prosthesis engagement rod 660 of the prosthesis deployment assembly 600, described below.[000215] As illustrated in Figs. 3H, 31 and 3 J, in a preferred embodiment, the internal prosthesis lumens 86a, 86b of the first and second elongated partially cylindrical sections 76a, 76b comprise a threaded region 87 proximate the proximal end 79a that is sized and configured to receive and threadably engage the threaded distal end 664 of the prosthesis engagement rod 660 of the prosthesis deployment assembly 600 and the prosthesis extraction rods or screws 702a, 702b of the prosthesis extraction assembly 700, also described below.[000216] In a preferred embodiment, the internal prosthesis lumens 86a, 86b are also configured to receive agents and compositions that further facilitate adhesion of the SI joint prosthesis 70a (and prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i) to the pilot SI openings of the invention; particularly, pilot SI joint opening 100 and, thereby, sacrum and / or ilium bone structures, and the aforementioned biologically active agents and compositions, including osteogenic agents and compositions, and pharmacological agents and compositions that facilitate osseous or bone tissue ingrowth into the SI joint prostheses of the invention and healing of the SI joint bone structures.[000217] As further illustrated in Figs. 3 A and 3B, in some embodiments of the invention, the SI joint prosthesis 70a further comprises a plurality of slots 90a and holes 92, which preferably are in communication with the internal prosthesis member lumens 86a, 86b.[000218] In a preferred embodiment, the agents and compositions referenced above are adapted to extrude through the slots 90a (including slots 90a of prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i and slots 90b of prosthesis 70h, discussed below) and holes 92 of the prosthesis 70a when the prosthesis 70a (and prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i) is inserted in a pilot SI joint opening (e.g., pilot SI joint opening 100), to, as indicated above, (i) further facilitate adhesion of the SI joint prosthesis 70a (and prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i) to the pilot SI openings of the invention and, thereby, sacrum and / or ilium, and (ii) facilitate osseous or bone tissue ingrowth into the SI joint prosthesis 70a (and prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i) and healing of the SI joint bone structures.[000219] Referring now to Figs. 3C and 3 J, in some embodiments, the bridge section 78a comprises a proximal bridge opening 88b that extends from the bridge section proximal end 81a to and, hence, in communication with the central opening 88a of the bridge section 78a. According to the invention, the proximal bridge opening 88b can comprise any suitable size and / or configuration.[000220] Referring back to Figs. 3 A and 3B, in a preferred embodiment, the distal end 81b of the bridge section or osteotome 78a preferably comprises a taper region 82a, which is configured and adapted to disrupt, i.e., cut into and through, articular cartilage and cortical bone 8 (and, in some aspects, trabecular bone 10), and, hence, facilitate advancement of SI joint prosthesis 70a into a dysfunctional SI joint.[000221] According to the invention, the taper region 82a of the bridge section 78a can comprise various configurations including, without limitation, X-bevel, wedge or bevel-shaped and Y-bevel.[000222] In some embodiments of the invention, the taper region 82a comprises two angled regions that intersect at a central point 83, such as shown in Figs. 3A and 3G.[000223] Referring now to Figs. 5 A - 5C, there is shown another embodiment of a SI joint prosthesis of the invention (denoted “70b”), which is similarly adapted to be advanced into a SI joint; particularly, a dysfunctional SI joint in a posterior trajectory.[000224] In a preferred embodiment, when the SI joint prosthesis 70b is advanced into a dysfunctional SI joint in a posterior trajectory, the prosthesis 70b similarly transfixes and, thereby, stabilizes the dysfunctional SI joint.[000225] As illustrated in Figs. 5A and 5B, the SI joint prosthesis 70b similarly comprises a monolithic structure comprising first and second elongated sections 76a, 76b, which similarly comprise the same features of the first and second elongated sections 76a, 76b of SI joint prosthesis 70a described above.[000226] As illustrated in Figs. 5B and 5C, the SI joint prosthesis 70b similarly comprises a bridge section or osteotome (in this embodiment, denoted “78b”), which, in this embodiment, comprises an off-set structure.[000227] As illustrated in Figs. 5B and 5C, the bridge section 78b is similarly disposed between the first and second elongated sections 76a, 76b, whereby the SI joint prosthesis 70b comprises a first interface of the bridge section 78b and the first elongated section 76a (denoted “Ii”) and a second interface of the bridge section 78b and the second elongated section 76b (denoted “h”).[000228] As illustrated in Fig. 5A, in a preferred embodiment, the bridge section 78b does not extend beyond the proximal and distal ends 79a, 79b of the first and second elongated sections 76a, 76b in a longitudinal direction. However, in some embodiments of the invention, the distal end 81b of the bridge section 78b extends beyond the distal ends 79b of the first and second elongated sections 76a, 76b.[000229] As further illustrated in Figs. 5B and 5C, in a preferred embodiment, the bridge section 78b comprises an arched or radius structure that is offset in a vertical direction relative to the first and second elongated sections 76a, 76b (denoted by arrow “VDi”), whereby the bridgesection 78b and the first and second elongated sections 76a, 76b define a prosthesis support member space between the first and second elongated sections 76a, 76b (denoted “SMSi”), which is preferably sized to accommodate positioning of a surgical dowl or pin therein, such as illustrated in Figs. 13 and 15, wherein the dowl is denoted “SD.”[000230] In a preferred embodiment, the prosthesis support member space SMSi comprises a size that is sufficient to receive and / or position a primary or supplemental joint support member or device, such as a surgical pin or screw (e.g., a sacral-alar iliac (S2AI) screw), in the prosthesis support member space SMSi when the prosthesis 70b is advanced into and / or positioned in a dysfunctional SI joint, such as illustrated in Fig. 13.[000231] In some embodiments, the offset of the bridge section 78b is further extended, such as illustrated in Fig. 5C, whereby the bridge section 78b extends beyond the first interface Ii of the bridge section 78b and the first elongated section 76a and a second interface h of the bridge section 78b and the second elongated section 76b to further facilitate the receipt and / or positioning of the primary or supplemental joint support member (or device) in the prosthesis support member space SMSi when the SI joint prosthesis 70b is advanced into and / or positioned in a dysfunctional SI joint.[000232] As illustrated in Fig. 5B, in a preferred embodiment, the distal end 81b of the bridge section 78b, i.e., offset radius structure, similarly comprises a taper region 82b, which is similarly configured and adapted to cut into and through at least articular cartilage and cortical bone, and, thereby facilitate advancement of SI joint prosthesis 70b into a dysfunctional SI joint. [000233] As illustrated in Fig. 5B, in a preferred embodiment, the first and second elongated sections 76a, 76b similarly comprise slots 90a, which are preferably in communication with the internal prosthesis member lumens 86a, 86b.[000234] According to the invention, the first and second elongated sections 76a, 76b can further comprise a plurality of holes that are substantially similar to the holes 92 of the prosthesis 70a.[000235] As illustrated in Fig. 5A, in a preferred embodiment, the bridge section 78b similarly comprises central opening 88a.[000236] As illustrated in Fig. 5C, according to the invention, the bridge section 78b can further comprise the bridge section opening 88b on the proximal end 81a (shown in phantom), which would similarly extend from the bridge section proximal end 81a to the central opening88a and, hence, be in communication therewith.[000237] According to the invention, the bridge section 78b can further comprise a plurality of slots similar to the slots 90a or holes similar to holes 92, illustrated in Fig. 3 A, with and without the central opening 88a.[000238] Referring now to Figs. 6A - 6C, there is shown another embodiment of a SI joint prosthesis of the invention (denoted “70c”), which is similarly adapted to be advanced into a dysfunctional SI joint in a posterior trajectory.[000239] In a preferred embodiment, when the SI joint prosthesis 70c is advanced into a dysfunctional SI joint in a posterior trajectory, the prosthesis 70c similarly transfixes and, thereby, stabilizes the dysfunctional SI joint.[000240] As illustrated in Figs. 6A and 6B, the SI joint prosthesis 70c similarly comprises a monolithic structure comprising first and second elongated sections 76a, 76b, which similarly comprise the same features of the first and second elongated sections 76a, 76b of SI joint prosthesis 70a described above.[000241] As illustrated in Figs. 6B and 6C, the SI joint prosthesis 70c similarly comprises a bridge section or osteotome (in this embodiment, denoted “78c”), which, in this embodiment, similarly comprises an off-set structure.[000242] As further illustrated in Figs. 6B and 6C, the bridge section 78c is similarly disposed between the first and second cylindrical sections 76a, 76b, whereby the prosthesis 70c similarly comprises a first interface of the bridge section 78c and the first elongated section 76a (denoted “Ii”) and a second interface of the bridge section 78c and the second elongated section 76b (denoted “I2”).[000243] As illustrated in Fig. 6A, in a preferred embodiment, the bridge section 78c similarly does not extend beyond the proximal and distal ends 79a, 79b of the first and second elongated sections 76a, 76b. However, in some embodiments of the invention, the distal end 81b of the bridge section 78c extends beyond the distal ends 79b of the first and second elongated sections 76a, 76b.[000244] As further illustrated in Figs. 6B and 6C, in a preferred embodiment, the bridge section 78c comprises a V-shaped structure that is similarly offset in a vertical direction relative to the first and second elongated sections 76a, 76b (again denoted by arrow “VDi”), whereby the bridge section 78c and the first and second elongated sections 76a, 76b similarly define aprosthesis support member space between the first and second elongated sections 76a, 76b (denoted “SMSi”).[000245] In a preferred embodiment, the prosthesis support member space SMSi of SI joint prosthesis 70c similarly comprises a size that is sufficient to receive and / or position a primary or supplemental joint support member or device, such as a surgical pin or screw, in the prosthesis support member space SMSi when the SI joint prosthesis 70c is advanced into and / or positioned in a dysfunctional SI joint.[000246] In some embodiments, the offset of the bridge section 78c is similarly further extended, such as illustrated in Fig. 6C, whereby the bridge section 78c similarly extends beyond the first interface Ii of the bridge section 78c and the first elongated section 76a and a second interface h of the bridge section 78c and the second elongated section 76b to further facilitate the receipt and / or positioning of the primary or supplemental joint support member (or device) in the prosthesis support member space SMSi when the SI joint prosthesis 70c is advanced into and / or positioned in a dysfunctional SI joint.[000247] As illustrated in Fig. 6B, in a preferred embodiment, the distal end 81b of the bridge section 78c, i.e., V-shaped structure, similarly comprises a taper region 82c that is similarly configured to cut into and through at least articular cartilage and cortical bone, and, thereby facilitate advancement of SI joint prosthesis 70c into a dysfunctional SI joint.[000248] As illustrated in Fig. 6A, in a preferred embodiment, the bridge section 78c similarly comprises central opening 88a.[000249] As illustrated in Fig. 6C, according to the invention, the bridge section 78c can similarly comprise the bridge section opening 88b on the proximal end 81a (shown in phantom), which would similarly extend from the bridge section proximal end 81a to the central opening 88a and, hence, be in communication therewith.[000250] According to the invention, the bridge section 78c can similarly comprise a plurality of slots similar to the slots 90a or holes similar to holes 92, illustrated in Fig. 3 A, with and without the central opening 88a.[000251] Referring now to Figs. 7A - 7C, there is shown another embodiment of a SI joint prosthesis of the invention (denoted “70d”), which is similarly adapted to be advanced into a dysfunctional SI joint in a posterior trajectory.[000252] In a preferred embodiment, when the SI joint prosthesis 70d is advanced into a dysfunctional SI joint in a posterior trajectory, the prosthesis 70d similarly transfixes and, thereby, stabilizes the dysfunctional SI joint.[000253] As illustrated in Figs. 7A and 7B, the SI joint prosthesis 70d similarly comprises a monolithic structure comprising first and second elongated sections 76a, 76b, which similarly comprise the same features of the first and second elongated sections 76a, 76b of SI joint prosthesis 70a described above.[000254] As illustrated in Figs. 7B and 7C, the prosthesis 70d similarly comprises a bridge section or osteotome (in this embodiment, denoted “78d”), which, in this embodiment, similarly comprises an off-set structure.[000255] As illustrated in Figs. 7B and 7C, the bridge section 78d is similarly disposed between the first and second elongated partially cylindrical sections 76a, 76b, whereby the prosthesis 70d similarly comprises a first interface of the bridge section 78d and the first elongated section 76a (denoted “Ii”) and a second interface of the bridge section 78d and the second elongated section 76b (denoted “I2”).[000256] As illustrated in Fig. 7A, in a preferred embodiment, the bridge section 78d similarly does not extend beyond the proximal and distal ends 79a, 79b of the first and second elongated sections 76a, 76b. However, in some embodiments of the invention, the distal end 81b of the bridge section 78d extends beyond the distal ends 79b of the first and second elongated sections 76a, 76b.[000257] As further illustrated in Figs. 7B and 7C, in a preferred embodiment, the bridge section 78d comprises a U-shaped structure that is similarly offset in a vertical direction relative to the first and second elongated sections 76a, 76b (again denoted by arrow “VDi”), whereby the bridge section 78d and the first and second elongated sections 76a, 76b similarly define a prosthesis support member space between the first and second elongated sections 76a, 76b (denoted “SMSi”).[000258] In a preferred embodiment, the prosthesis support member space SMSi of SI joint prosthesis 70d similarly comprises a size that is sufficient to receive and / or position a primary or supplemental joint support member or device, such as a surgical pin or screw, in the prosthesis support member space SMSi when the prosthesis 70d is advanced into and / or positioned in a dysfunctional SI joint.[000259] In some embodiments, the offset of the bridge section 78d is similarly further extended, such as illustrated in Fig. 7C, whereby the bridge section 78d similarly extends beyond the first interface Ii of the bridge section 78d and the first elongated section 76a and a second interface I2 of the bridge section 78d and the second elongated section 76b to further facilitate the receipt and / or positioning of the primary or supplemental joint support member (or device) in the prosthesis support member space SMSi when the SI joint prosthesis 70d is advanced into and / or positioned in a dysfunctional SI joint.[000260] As illustrated in Fig. 7B, in a preferred embodiment, the distal end 81b of the bridge section 78d, i.e., U-shaped structure, similarly comprises a taper region 82d that is similarly configured to cut into and through at least articular cartilage and cortical bone, and, thereby facilitate advancement of SI joint prosthesis 70d into a dysfunctional SI joint.[000261] As illustrated in Fig. 7A, in a preferred embodiment, the bridge section 78d similarly comprises central opening 88a.[000262] As illustrated in Fig. 7C, according to the invention, the bridge section 78d can similarly further comprise the bridge section opening 88b on the proximal end 81a (shown in phantom), which would similarly extend from the bridge section proximal end 81a to the central opening 88a and, hence, in communication therewith.[000263] According to the invention, the bridge section 78d can similarly further comprise a plurality of slots similar to the slots 90a or holes similar to holes 92, illustrated in Fig. 3 A, with and without the central opening 88a.[000264] Referring now to Figs. 8A - 8C, there is shown another embodiment of a SI joint prosthesis of the invention (denoted “70e”), which is similarly adapted to be advanced into a dysfunctional SI joint in a posterior trajectory.[000265] In a preferred embodiment, when the SI joint prosthesis 70e is advanced into a dysfunctional SI joint in a posterior trajectory, the SI joint prosthesis 70e similarly transfixes and, thereby, stabilizes the dysfunctional SI joint.[000266] As illustrated in Figs. 8A and 8B, the SI joint prosthesis 70e similarly comprises a monolithic structure comprising first and second elongated sections 76a, 76b, which comprise the same features of the first and second elongated sections 76a, 76b of SI joint prosthesis 70a described above.[000267] As further illustrated in Figs. 8A and 8B, the prosthesis 70e similarly comprises a bridge section or osteotome (in this embodiment, denoted “78e”), which, in this embodiment, similarly comprises an off-set structure.[000268] As illustrated in Figs. 8B and 8C, the bridge section 78e is similarly disposed between the first and second elongated partially cylindrical sections 76a, 76b, whereby the prosthesis 70e similarly comprises a first interface of the bridge section 78e and the first elongated section 76a (denoted “Ii”) and a second interface of the bridge section 78e and the second elongated section 76b (denoted “I2”).[000269] As illustrated in Fig. 8A, in a preferred embodiment, the bridge section 78e similarly does not extend beyond the proximal and distal ends 79a, 79b of the first and second elongated sections 76a, 76b. However, in some embodiments of the invention, the distal end 81b of the bridge section 78e similarly extends beyond the distal ends 79b of the first and second elongated sections 76a, 76b.[000270] As further illustrated in Figs. 8B and 8C, in a preferred embodiment, the bridge section 78e comprises a planar-shaped structure that is similarly offset in a vertical direction relative to the first and second elongated sections 76a, 76b (again denoted by arrow “VDi”), whereby the bridge section 78e and the first and second elongated sections 76a, 76b similarly define a prosthesis support member space between the first and second elongated sections 76a, 76b (denoted “SMSi”).[000271] In a preferred embodiment, the prosthesis support member space SMSi of SI joint prosthesis 70e similarly comprises a size that is sufficient to receive and / or position a primary or supplemental joint support member or device, such as a surgical pin or screw, in the prosthesis support member space SMSi when the prosthesis 70e is advanced into and / or positioned in a dysfunctional SI joint.[000272] As further illustrated in Fig. 8C, in some embodiments, the inner surface 78c' of the bridge section 78e comprises a curvilinear shape to further facilitate the receipt and / or positioning of the primary or supplemental joint support member (or device) in the prosthesis support member space SMSi when the prosthesis 70e is advanced into and / or positioned in a dysfunctional SI joint.[000273] As illustrated in Fig. 8B, in a preferred embodiment, the distal end 81b of the bridge section 78e similarly comprises a taper region 82e that is similarly configured to cut into andthrough at least articular cartilage and cortical bone and, thereby, facilitate advancement of SI joint prosthesis 70e into a dysfunctional SI joint.[000274] As illustrated in Fig. 8A, in a preferred embodiment, the bridge section 78e similarly comprises central opening 88a.[000275] As illustrated in Fig. 8C, according to the invention, the bridge section 78e can similarly further comprise the bridge section opening 88b on the proximal end 81a (shown in phantom), which would similarly extend from the bridge section proximal end 81a to the central opening 88a and, hence, in communication therewith.[000276] According to the invention, the bridge section 78e can similarly further comprise a plurality of slots or holes similar to slots 90a and holes 92 of prosthesis 70a illustrated in Fig. 3A. [000277] Referring now to Figs. 9A - 9C, there is shown another embodiment of a prosthesis of the invention (denoted “70f ’), which is similarly adapted to be advanced into a dysfunctional SI joint in a posterior trajectory.[000278] In a preferred embodiment, when the SI joint prosthesis 70f is advanced into a dysfunctional SI joint in a posterior trajectory, the SI joint prosthesis 70f similarly transfixes and, thereby, stabilizes the dysfunctional SI joint.[000279] As illustrated in Figs. 9A and 9B, the prosthesis 70f similarly comprises a monolithic structure comprising first and second elongated sections 76a, 76b, which similarly comprise the same features of the first and second elongated sections 76a, 76b of SI joint prosthesis 70a described above.[000280] As illustrated in Figs. 9B and 9C, the SI joint prosthesis 70f similarly comprises a bridge section (in this embodiment, denoted “78f ’), which, in this embodiment, comprises an open structure comprising separate top and bottom bridge members 89a, 89b.[000281] As further illustrated in Fig. 9C, in a preferred embodiment, the open structure of the bridge section 78f comprises an ovate shape.[000282] As illustrated in Figs. 9C and 9D, in a preferred embodiment, the open region of the open bridge structure is disposed between the top and bottom bridge members 89a, 89b, whereby the SI joint prosthesis 70f comprises a first interface (denoted “Ii”) of the top bridge member 89a at a first top region (denoted “TRi”) of the first elongated section 76a and a second interface (denoted “I2”) of the top bridge member 89a at a second top region (denoted “TR2”) of the second elongated section 76b, a third interface (denoted “I3”) of the bottom bridge member 89band at a first bottom region (denoted “BRi”) of the first elongated section 76a and a fourth interface (denoted “I4”) of the bottom bridge member 89b at a second bottom region (denoted “BR2”) of the second elongated section 76b.[000283] In a preferred embodiment, the first interface Ii of the top bridge member 89a and the first elongated section 76a and the third interface I3 of the bottom bridge member 89b and the first elongated section 76a are spaced a first distance apart, and the second interface I2 of the top bridge member 89a and the second elongated section 76b and the fourth interface I4 of the bottom bridge member 89b and the second elongated section 76b are spaced a second distance apart.[000284] As indicated above and illustrated in Fig. 9C, in a preferred embodiment, the top and bottom bridge members 89a, 89b and the first and second elongated sections 76a, 76b define a prosthesis support member space (i.e., open region of the open bridge structure) between the top and bottom bridge members 89a, 89b and the first and second elongated sections 76a, 76b (denoted “SMS2”).[000285] In a preferred embodiment, the prosthesis support member space SMS2 of SI joint prosthesis 70f is similarly sized and configured to facilitate the receipt and / or positioning of a primary or supplemental joint support member or device, such as a surgical pin or screw, in the prosthesis support member space SMS2 of SI joint prosthesis 70f when prosthesis 70f is advanced into and / or positioned in a dysfunctional SI joint, such as illustrated in Fig. 14 wherein the supplemental support is denoted “SS”[000286] In a preferred embodiment, the prosthesis support member space SMS2 comprises a minimum height (denoted “H”) proximate the vertical axis of prosthesis 70f (denoted “Va”) in the range of 25.0 mm to 17.0 mm, more preferably, in the range of 20.0 mm to 17.0 mm.[000287] In some embodiments, the bridge section 78f is offset relative to the first and second elongated sections 76a, 76b, such as illustrated in Fig. 9C, whereby the top bridge member 89a of the bridge section 78f extends beyond the first interface Ii of the top bridge member 89a and the first elongated section 76a and the second interface I2 of the top bridge member 89a and the second elongated section 76b in a first vertical direction (denoted again by arrow “VDi”), and the bottom bridge member 89b of the bridge section 78f extends beyond the third interface I3 of the bottom bridge member 89b and the first elongated section 76a and the fourth interface I4 of the bottom bridge member 89b and the second elongated section 76b in a second verticaldirection (denoted by arrow “VD2”) to further facilitate the receipt and / or positioning of a primary or supplemental joint support member (or device) in the prosthesis support member space SMS2 when the prosthesis 70f is advanced into and / or positioned in a dysfunctional SI joint, such as illustrated in Fig. 14.[000288] As illustrated in Fig. 9A, in a preferred embodiment, the top and bottom bridge members 89a, 89b similarly comprise a central opening 88a.[000289] As illustrated in Fig. 9B, in a preferred embodiment, the distal ends 81b of the top and bottom bridge members 89a, 89b similarly comprise taper regions 82b that are configured to cut into and through at least articular cartilage and cortical bone and, thereby, facilitate advancement of SI joint prosthesis 70f into a dysfunctional SI joint.[000290] According to the invention, the top and / or bottom bridge members 89a, 89b can similarly further comprise a plurality of slots and / or holes similar to the slots 90a and holes 92 of prosthesis 70a illustrated in Fig. 3A.[000291] Referring now to Figs. 10A - 10C, there is shown another embodiment of a prosthesis of the invention (denoted “70g”), which is similarly adapted to be advanced into a dysfunctional SI joint in a posterior trajectory.[000292] In a preferred embodiment, when the SI joint prosthesis 70g is advanced into a dysfunctional SI joint in a posterior trajectory, the SI joint prosthesis 70g similarly transfixes and, thereby, stabilizes the dysfunctional SI joint.[000293] As illustrated in Figs. 10A and 10B, the SI joint prosthesis 70g similarly comprises a monolithic structure comprising first and second elongated sections 76a, 76b, which similarly comprise the same features of the first and second elongated sections 76a, 76b of SI joint prosthesis 70a described above.[000294] As further illustrated in Figs. 10A and 10B, the SI joint prosthesis 70g similarly also comprises a bridge section (in this embodiment, denoted “78g”).[000295] As illustrated in Figs. 10A and 10B, in a preferred embodiment, the bridge section 78g comprises an open structure comprising separate opposing V-shaped top and bottom bridge members 89c, 89d.[000296] As illustrated in Fig. 10D, the open region of the open bridge structure is similarly disposed between the first and second elongated sections 76a, 76b, whereby the prosthesis 70g comprises a first interface (denoted “Ii”) of the top bridge member 89c at a first top region(denoted “TRi”) of the first elongated section 76a and a second interface (denoted “I2”) of the top bridge member 89c at a second top region (denoted “TR2”) of the second elongated section 76b, a third interface (denoted “I3”) of the bottom bridge member 89d and at a first bottom region (denoted “BRi”) of the first elongated section 76a and a fourth interface (denoted “I4”) of the bottom bridge member 89d at a second bottom region (denoted “BR2”) of the second elongated section 76b.[000297] In a preferred embodiment, the first interface Ii of the top bridge member 89c and the first elongated section 76a and the third interface I3 of the bottom bridge member 89d and the first elongated section 76a are spaced a first distance apart, and the second interface I2 of the top bridge member 89c and the second elongated section 76b and the fourth interface I4 of the bottom bridge member 89d and the second elongated section 76b are spaced a second distance apart.[000298] As indicated above and illustrated in Fig. 10C, in a preferred embodiment, the top and bottom bridge members 89c, 89d and the first and second elongated sections 76a, 76b similarly define a prosthesis support member space (i.e., open region of the open structure) between the top and bottom bridge members 89c, 89d and the first and second elongated sections 76a, 76b (again denoted “SMS2”).[000299] In a preferred embodiment, the prosthesis support member space SMS2 of SI joint prosthesis 70g is similarly sized and configured to facilitate the receipt and / or positioning of a primary or supplemental joint support member or device, such as a surgical pin or screw, in the prosthesis support member space SMS2 of SI joint prosthesis 70g when prosthesis 70g is advanced into and / or positioned in a dysfunctional SI joint.[000300] In a preferred embodiment, the prosthesis support member space SMS2 of SI joint prosthesis 70g similarly comprises a minimum height (denoted “H”) proximate the vertical axis (denoted “Va”) in the range of 25.0 mm to 17.0 mm, more preferably, in the range of 20.0 mm to 17.0 mm.[000301] In some embodiments, the bridge section 78g is similarly offset relative to the first and second elongated sections 76a, 76b, such as illustrated in Fig. 10C, whereby the top bridge member 89c of the bridge section 78g extends beyond the first interface Ii of the top bridge member 89c and the first elongated section 76a and the second interface I2 of the top bridge member 89c and the second elongated section 76b in a first vertical direction (denoted again byarrow “VDi”), and the bottom bridge member 89d of the bridge section 78g extends beyond the third interface I3 of the bottom bridge member 89d and the first elongated section 76a and the fourth interface I4 of the bottom bridge section 89d and the second elongated section 76b in a second vertical direction (denoted by arrow “VD2”) to further facilitate receipt and / or positioning of a primary or supplemental joint support member (or device) in the prosthesis support member space SMS2 of SI joint prosthesis 70g when prosthesis 70g is advanced into and / or positioned in a dysfunctional SI joint.[000302] As illustrated in Figs. 10A and 10B, in a preferred embodiment, the top and bottom bridge members 89c, 89d similarly comprise central opening 88a.[000303] As illustrated in Fig. 10B, in a preferred embodiment, the distal ends 81b of the top and bottom bridge members 89c, 89d similarly comprise taper regions 82c that are configured to cut into and through at least articular cartilage and cortical bone and, thereby, facilitate advancement of SI joint prosthesis 70g into a dysfunctional SI joint.[000304] According to the invention, the top and / or bottom bridge members 89c, 89d can similarly further comprise a plurality of slots similar to the slots 90a of the first and second elongated sections 76a, 76b.[000305] Referring now to Figs. 11 A - 11C, there is shown another embodiment of a SI joint prosthesis of the invention (denoted “70h”), which similarly comprise the same features of the first and second elongated sections 76a, 76b of SI joint prosthesis 70a described above.[000306] In a preferred embodiment, when the SI joint prosthesis 70h is advanced into a dysfunctional SI joint in a posterior trajectory, the SI joint prosthesis 70h similarly transfixes the dysfunctional SI joint.[000307] As illustrated in Figs. 11A and 1 IB, the SI joint prosthesis 70h similarly comprises a monolithic structure comprising first and second elongated sections 76a, 76b, which are similarly adapted to be advanced into the sacrum and ilium bone structures of a dysfunctional SI joint when the SI joint prosthesis 70h is advanced into the dysfunctional SI joint in a posterior trajectory.[000308] As further illustrated in Figs. 11A and 1 IB, the SI joint prosthesis 70h similarly also comprises a bridge section (in this embodiment, denoted “78h”).[000309] As additionally illustrated in Figs. 1 IB and 11C, in a preferred embodiment, the bridge section 78h comprises an open structure comprising separate opposing U-shaped top andbottom bridge members 89e, 89f.[000310] As illustrated in Fig. 1 ID, the open region of the open bridge structure is similarly disposed between the first and second elongated sections 76a, 76b, whereby the prosthesis 70h comprises a first interface (denoted “Ii”) of the top bridge member 89e at a first top region (denoted “TRi”) of the first elongated section 76a and a second interface (denoted “If’) of the top bridge member 89e at a second top region (denoted “TR2”) of the second elongated section 76b, a third interface (denoted “I3”) of the bottom bridge member 89f and at a first bottom region (denoted “BRi”) of the first elongated section 76a and a fourth interface (denoted “I4”) of the bottom bridge member 89f at a second bottom region (denoted “BR2”) of the second elongated section 76b.[000311] In a preferred embodiment, the first interface Ii of the top bridge member 89e and the first elongated section 76a and the third interface I3 of the bottom bridge member 89f and the first elongated section 76a are spaced a first distance apart, and the second interface I2 of the top bridge member 89e and the second elongated section 76b and the fourth interface I4 of the bottom bridge member 89f and the second elongated section 76b are spaced a second distance apart.[000312] As indicated above and illustrated in Fig. 11C, in a preferred embodiment, the top and bottom bridge members 89e, 89f and the first and second elongated sections 76a, 76b similarly define a prosthesis support member space (i.e., open region of the open structure) between the top and bottom bridge members 89e, 89f and the first and second elongated sections 76a, 76b (again denoted “SMS2”).[000313] In a preferred embodiment, the prosthesis support member space SMS2 of SI joint prosthesis 70h is similarly sized and configured to facilitate the receipt and / or positioning of a primary or supplemental joint support member or device, such as a surgical pin or screw, in the prosthesis support member space SMS2 of SI joint prosthesis 70h when prosthesis 70h is advanced into and / or positioned in a dysfunctional SI joint.[000314] In a preferred embodiment, the prosthesis support member space SMS2 of SI joint prosthesis 70h similarly comprises a minimum height (denoted “H”) proximate the vertical axis (denoted “Va”) in the range of 25.0 mm to 17.0 mm, more preferably, in the range of 20.0 mm to 17.0 mm.[000315] In some embodiments, the bridge section 78h is similarly offset relative to the first and second elongated sections 76a, 76b, such as illustrated in Fig. 11C, whereby the top bridge member 89e of the bridge section 78h extends beyond the first interface Ii of the top bridge member 89e and the first elongated section 76a and the second interface b of the top bridge member 89e and the second elongated section 76b in a first vertical direction (denoted again by arrow “VDi”), and the bottom bridge member 89f of the bridge section 78h extends beyond the third interface I3 of the bottom bridge member 89f and the first elongated section 76a and the fourth interface I4 of the bottom bridge section 89f and the second elongated section 76b in a second vertical direction (denoted by arrow “VD2”) to further facilitate receipt and / or positioning of a primary or supplemental joint support member (or device) in the prosthesis support member space SMS2 of prosthesis 70h when SI joint prosthesis 70h is advanced into and / or positioned in a dysfunctional SI joint.[000316] As illustrated in Figs. 11 A and 1 IB, in a preferred embodiment, the top and bottom bridge members 89e, 89f similarly comprise central opening 88a.[000317] As illustrated in Fig. 1 IB, in a preferred embodiment, the distal ends 81b of the top and bottom bridge members 89e, 89f similarly comprise taper regions 82d that are configured to cut into and through at least articular cartilage and cortical bone and, thereby, facilitate advancement of SI joint prosthesis 70h into a dysfunctional SI joint.[000318] According to the invention, the top and / or bottom bridge members 89e, 89f can similarly further comprise a plurality of slots similar to the slots 90a in the first and second elongated sections 76a, 76b.[000319] Referring now to Figs. 12A - 12D, there is shown another embodiment of a SI joint prosthesis of the invention (denoted “70i”), which is similarly adapted to be advanced into a dysfunctional SI joint in a posterior trajectory.[000320] In a preferred embodiment, when the SI joint prosthesis 70i is advanced into a dysfunctional SI joint in a posterior trajectory, the SI joint prosthesis 70h similarly transfixes and, thereby, stabilizes the dysfunctional SI joint.[000321] As illustrated in Figs. 12A and 12B, the SI joint prosthesis 70i similarly comprises a monolithic structure comprising first and second elongated sections 76a, 76b, which similarly comprise the same features of the first and second elongated sections 76a, 76b of SI joint prosthesis 70a described above.[000322] As further illustrated in Figs. 12A and 12B, the SI joint prosthesis 70i similarly also comprises a bridge section (in this embodiment, denoted “78i”).[000323] As illustrated in Figs. 12B and 12C, in a preferred embodiment, the bridge section 78i comprises an open structure comprising separate opposing planar-shaped top and bottom bridge members 89g, 89h.[000324] As illustrated in Fig. 12D, the open region of the open bridge structure is similarly disposed between the first and second elongated sections 76a, 76b, whereby the SI joint prosthesis 70i comprises a first interface (denoted “Ii”) of the top bridge member 89g at a first top region (denoted “TRi”) of the first elongated section 76a and a second interface (denoted “I2”) of the top bridge member 89g at a second top region (denoted “TR2”) of the second elongated section 76b, a third interface (denoted “I3”) of the bottom bridge member 89h and at a first bottom region (denoted “BRi”) of the first elongated section 76a and a fourth interface (denoted “I4”) of the bottom bridge member 89h at a second bottom region (denoted “BR2”) of the second elongated section 76b.[000325] In a preferred embodiment, the first interface Ii of the top bridge member 89g and the first elongated section 76a and the third interface I3 of the bottom bridge member 89h and the first elongated section 76a are spaced a first distance apart, and the second interface I2 of the top bridge member 89g and the second elongated section 76b and the fourth interface I4 of the bottom bridge member 89h and the second elongated section 76b are spaced a second distance apart.[000326] As indicated above and illustrated in Fig. 12C, in a preferred embodiment, the top and bottom bridge members 89g, 89h and the first and second elongated sections 76a, 76b similarly define a prosthesis support member space (i.e., open region of the open structure) between the top and bottom bridge members 89g, 89h and the first and second elongated sections 76a, 76b (again denoted “SMS2”).[000327] In a preferred embodiment, the prosthesis support member space SMS2 of prosthesis 70i is similarly sized and configured to facilitate the receipt and / or positioning of a primary or supplemental joint support member or device, such as a surgical pin or screw, in the prosthesis support member space SMS2 of SI joint prosthesis 70i when prosthesis 70i is advanced into and / or positioned in a dysfunctional SI joint.[000328] In a preferred embodiment, the prosthesis support member space SMS2 of SI joint prosthesis 70i similarly comprises a minimum height (denoted “H”) proximate the vertical axis (denoted “Va”) in the range of 25.0 mm to 17.0 mm, more preferably, in the range of 20.0 mm to 17.0 mm.[000329] As illustrated in Figs. 12A and 12B, in a preferred embodiment, the top and bottom bridge members 89g, 89h similarly comprise central opening 88a.[000330] As further illustrated in Fig. 12B, in a preferred embodiment, the distal ends 81b of the top and bottom bridge members 89g, 89h similarly comprise taper regions 82e that are configured to cut into and through at least articular cartilage and cortical bone, and, thereby, facilitate advancement of Sljoint prosthesis 70i into a dysfunctional SI joint.[000331] According to the invention, the top and / or bottom bridge members 89e, 89f can similarly further comprise a plurality of slots similar to the slots 90a in the first and second elongated sections 76a, 76b.[000332] As indicated above, in a preferred embodiment, Sljoint prostheses 70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i discussed above, are specifically adapted to be advanced into dysfunctional SI joints in a posterior trajectory, wherein the prostheses transfix the dysfunctional SI joints, as defined herein.[000333] According to the invention, the Sljoint prostheses with offset bridge structures, i.e., Sljoint prostheses 70b, 70c, 70d and 70e, can be advanced into dysfunctional SI joints in different orientations. In a preferred embodiment, the orientations include (i) a first orientation, wherein the offset bridge structure is disposed on a first plane, whereby the offset bridge structure is disposed proximate the bottom of a prior surgical implant (e.g., surgical pin, dowel or screw), such as illustrated in Fig. 13, or a new surgical implant, and (ii) a second orientation, wherein the offset bridge structure is disposed on a second plane, whereby the offset bridge structure is disposed proximate the top of a prior surgical implant or a new surgical implant.[000334] In a preferred embodiment, when Sljoint prostheses 70b, 70c, 70d and 70e are advanced into dysfunctional SI joints, the prior surgical implant or new surgical implant is spaced a distance in the range of 4.0 mm to 7.0 mm from the offset bridge structures thereof. [000335] According to the invention, the Sljoint prostheses of the invention, i.e., Sljoint prostheses 70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i, can comprise various biocompatible materials, including metals and metal alloys, such as titanium, stainless-steel, cobalt-chromiumalloys, and nickel -titanium alloys.[000336] SI joint prostheses 70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i can also comprise various biocompatible polymers, including, without limitation, reinforced polymers, such as carbon fiber reinforced polymers and metal-framed polymers.[000337] According to the invention, SI joint prostheses 70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i can also comprise porous structures to facilitate (i) adhesion of prostheses to a postprosthesis insertion SI joint opening of the invention; particularly, post-prosthesis insertion SI joint opening 200 and, thereby, to SI joint bone structures, i.e., sacrum and ilium bone structures, and (ii) bone or osseous tissue ingrowth into the SI joint prostheses.[000338] According to the invention, SI joint prostheses 70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i can also comprise various exterior surface textures and roughness to facilitate or enhance engagement of the prostheses to a post-prosthesis insertion SI joint opening, such as postprosthesis insertion SI joint opening 200, and, thereby, to SI joint bone structures, i.e., sacrum and ilium bone structures, and / or maintain engagement thereto and positioning therein.[000339] According to the invention, the surface(s) of the SI joint prostheses of the invention can comprise a roughness grade number of N1 (Ra = -0.025 pm), N2 (Ra = -0.05 pm), N3 (Ra = -0.1 pm), N4 (Ra = -0.2 pm), N5 (Ra = -0.4 pm), N6 (Ra = -0.08 pm), N7 (Ra = -1.6 pm), N8 (Ra = -3.2 pm), N9 (Ra = -6.3 pm), N10 (Ra = -12.5 pm), Ni l (Ra = -25.0 pm) or N12 (Ra = -50.0 pm) to facilitate or enhance engagement of the SI joint prostheses to SI joint bone structures and / or maintain engagement thereto and positioning therein.[000340] According to the invention, SI joint prostheses 70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i can also comprise an outer coating.[000341] According to the invention, the outer coating can comprise a biocompatible and, preferably, biodegradable adhesive composition. Suitable adhesive compositions include, without limitation, poly(L-glutamic acid)-based compositions, poly(y-glutamic acid)-based compositions, poly(alkyl cyano acrylate)-based compositions, polyacrylic acid-based compositions, including polyacrylic acid crosslinked with pentaerythritol and / or allyl sucrose, polyacrylic acid crosslinked with divinyl glycol and combinations thereof; fibrin-based compositions, collagen-based compositions, including collagen and poly(L-glutamic acid) compositions; albumin-based compositions, including BioGlue® (comprises purified bovine serum albumin (BSA) and glutaraldehyde); cyanoacrylate compositions, including butyl-2-cyanoacrylate adhesives (e.g., Indermil®, Histoacryl®, Histoacryl® Blue, and LiquiBand®) and octyl-2-cyanoacrylate adhesives (e.g., Dermabond®, SurgiSeal™, LiquiBand® Flex, and OctylSeal); polyethylene glycol) (PEG) based compositions, including FocalSeal®, Progel™, Duraseal™, DuraSeal™ Xact, Coseal® and ReSure Sealant; polysaccharide-based compositions, polypeptide-based compositions, and radiation curable materials, such as poly(glycerol-co- sebacate) acrylate (PGSA), discussed below.[000342] According to the invention, the outer coating can also comprise a biologically active composition comprising one of the aforementioned biologically active agents or a pharmacological composition comprising one of the forementioned pharmacological agents.[000343] According to the invention, the outer coating can also comprise one of the aforementioned polymers and / or compositions comprising same.[000344] In some embodiments, the aforementioned polymer compositions comprise one or more of the aforementioned biologically active agents or pharmacological agents.[000345] In some embodiments of the invention, the polymer comprises poly(glycerol sebacate) (PGS) or a derivative thereof, including, without limitation, poly(glycerol-co-sebacate) acrylate (PGSA) and PGS co-polymers, such as poly(glycerol sebacate)-co-poly(ethylene glycol) (PGS-PEG); and / or composites thereof, e.g., PGS -hydroxyapatite (HA) composites and PGS- poly(s-caprolactone) (PGS-PCL) composites, and compositions comprising same.[000346] PGS and derivatives thereof possess a unique property of inducing remodeling of damaged osseous or bone tissue, such as at pilot SI joint openings, and, hence, healing of the associated bone structures when disposed proximate thereto.[000347] A further seminal property of PGS, which is set forth in Table I below, is that its physical state can be modulated during synthesis by controlling the “degree of esterification” via at least one crosslinking agent, e.g., methylene diphenyl diisocyanate (MDI).Table 1[000348] According to the invention, any suitable degree of esterification of PGS can be employed for PGS when employed in or for PGS based outer coatings (i.e., polymer compositions comprising PGS) and biologically active agent compositions of the invention. [000349] In some embodiments, the PGS based outer coatings comprise a degree of esterification in the range of -76% - 83%, whereby the PGS exhibits adhesive properties, which will enhance engagement of the SI joint prostheses of the invention; particularly SI joint prostheses 70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i to SI joint bone structures, i.e., sacrum and ilium bone structures.[000350] As is well established, the physical state of poly(glycerol-co-sebacate) acrylate (PGSA) can also be modulated by combining the PGSA with a suitable photoinitiator and subjecting the PGSA to radiation.[000351] Indeed, as set forth in Nijst, et al., Synthesis and Characterization of Photocurable Elastomers from PolyfGlycerol-Co-Sebacate)^ Biomacromolecules, vol. 8, no. 10, pp. 3067- 3073 (2007), PGSA can be induced to transition from a liquid or flowable state to a solid elastomer state when combined with a photoinitiator, such as 2-hydroxy-l-[4-hydroxy ethoxy) phenyl]-2-methyl-l -propanone (D 2959, Ciba Geigy), 2,2-dimethoxy-2-phenylacetophenone, titanocenes, fluorinated diaryltitanocenes, iron arene complexes, manganese decacarbonyl and methylcyclopentadienyl manganese tri carbonyl, and subjected to radiation, such as visible light; particularly, radiation in the range of approximately 380.0 nm - 750.0 nm, and ultraviolet (UV) light, particularly, radiation in the range of 10.0 nm - 400.0 nm.[000352] Thus, in some embodiments, a composition comprising PGSA (also referred to herein as a “PGSA based composition” and “fixation composition”) is employed to enhance the engagement of SI joint prostheses 70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i to postprosthesis insertion SI joint openings, such as post-prosthesis insertion Sljoint opening 200 and, thereby, Sljoint bone structures, i.e., sacrum and ilium bone structures.[000353] In some embodiments, the PGSA based composition (in a flowable state) is thus disposed in the internal prosthesis lumens 86a, 86b of Sljoint prostheses 70a, 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i, whereby the PGSA based composition is dispersed when the Sljoint prostheses are positioned in the dysfunctional Sljoint and fills any gaps between the Sljoint prostheses and Sljoint openings and, thereby, Sljoint bone structures, and is thereafter cured via radiation and solidified, whereby the solidified PGSA enhances the engagement of the prosthesesto the sacrum and ilium bone structures.[000354] PGS and its derivatives; particularly, PGS A are also excellent platforms for delivery and, hence, administration of biologically active agents and pharmacological agents to mammalian tissue, including osseous or bone tissue.[000355] Thus, in some embodiments of the invention, the PGS based outer coatings and PGS and PGSA based compositions further comprise one or more of the aforementioned biologically active or pharmacological agents.Drill Guide Assembly[000356] As indicated above, in a preferred embodiment of the invention, the systems for stabilizing dysfunctional SI joints further comprise a drill guide assembly configured and adapted to access the target dysfunctional SI joint via a posterior approach and create at least one pre-determined pilot SI joint opening in the dysfunctional SI joint.[000357] Referring now to Fig. 16A, there is shown a preferred embodiment of a drill guide assembly 500 of the invention.[000358] As illustrated in Fig. 16A, the drill guide assembly 500 comprises a bone dislodging system 40, an access sleeve 502, a drill guide 520 and a guide pin 530.[000359] Referring now to Figs. 16B-16D, there is shown a preferred embodiment of the access sleeve 502.[000360] As illustrated in Figs. 16B-16D, the access sleeve 502 comprises proximal and distal ends 504a, 504b, and an internal opening 506 that extends from the proximal end 504a to the distal end 504b of the access sleeve 502, and a plurality of lumens 507, which, as illustrated in Fig. 16A, are sized and configured to receive and position Kirschner wires (K-wires) 509 or similar pin structures therein.[000361] As illustrated in Fig. 16A, in a preferred embodiment, the access sleeve internal opening 506 is sized and configured to receive and position the drill guide 520 therein.[000362] As further illustrated in Figs. 16B and 16D, the proximal end 504a of the access sleeve 502 comprises a planar region 503, which, as illustrated in Fig. 16A, is configured to seat the proximal end 522a of the drill guide 520 (discussed below) thereon.[000363] In a preferred embodiment, as additionally shown in Figs. 16B and 16D, the proximal end 504a of the access sleeve 502, i.e., planar region 503, further comprises two (2) threaded holes 505a, 505b, which are preferably disposed on opposing edge regions of the planar region503. According to the invention, the threaded holes 505a, 505b are sized and configured to receive the threaded end 514 of the access sleeve handle 510, discussed below.[000364] Referring now to Figs. 16E and 16F, there is shown a preferred embodiment of the access sleeve handle 510.[000365] As illustrated in Figs. 16E and 16F, the access sleeve handle 510 preferably comprises an elongated cylindrical shaped member comprising proximal and distal ends 512a, 512b.[000366] As further illustrated in Fig. 16E, in a preferred embodiment, the distal end 512b of the access sleeve handle 510 comprises a threaded extension 514 that is sized and configured to cooperate with the threaded holes 505a, 505b of the access sleeve 502, whereby the access sleeve handle 510 can be threadably engaged to the access sleeve 502.[000367] Referring now to Figs. 16G-16J, there is shown a preferred embodiment of the drill guide 520.[000368] As illustrated in Figs. 16G-16J, the drill guide 520 comprises proximal and distal ends 522a, 522b, a pair of drill guide lumens 524a, 524b and a drill guide medial lumen 526; the drill guide lumens 524a, 524b and drill guide medial lumen 526 extending from the proximal end 522a to the distal end 522b of the drill guide 520.[000369] As illustrated in Fig. 16A, in a preferred embodiment, the drill guide lumens 524a, 524b are sized and configured to receive (i) the bone dislodging system 40, in this instance, the drill bit 41 shown in Fig. 16L, and (ii) the guide pin 530 shown in Fig. 16K and discussed below. [000370] In a preferred embodiment, the drill guide medial lumen 526 is sized and configured to receive an elongated guide probe, which is preferably initially positioned in the dysfunctional SI joint to guide the drill guide 520 to a desired position proximate the dysfunctional SI joint.[000371] According to the invention, the drill guide internal lumens 524a, 524b and drill guide medial lumen 526 can also be sized and configured to receive various other suitable instruments, such as surgical scopes, center punches, location pins, drill probes and drill stop assemblies, to facilitate the creation of a pilot SI joint opening.[000372] Referring back to Figs. 16G and 16H, in a preferred embodiment, the proximal end 522a of the drill guide 520 comprises a planar configuration comprising an extended region 523, which, as illustrated in Fig. 16A, is sized and configured to abut the proximal end 504a of the access sleeve 502 to position the drill guide 520 therein.[000373] Referring now to Fig. 16K, there is shown one embodiment of a guide pin 530 of the invention.[000374] As illustrated in Fig. 16K, the guide pin 530 preferably comprises an elongated guide member 532 comprising proximal and distal ends 534a, 534b. The guide pin 530 further comprises a handle 536 that is operatively connected to the proximal end 534a of the guide member 532.[000375] Referring now to Fig. 17A, there is shown pilot SI joint opening 100 referenced above, which is one embodiment of a pilot SI joint opening that can be created by the drill guide assembly 500, described above.[000376] As illustrated in Fig. 17A and indicated above, the pilot SI joint opening 100 comprises two three-dimensional pilot or guide portions or regions 103, 104; the first guide portion 103 being disposed in the sacrum 2 and the second guide portion 104 being disposed in the ilium 4.[000377] As further illustrated in Fig. 17A and indicated above, the sacrum and ilium guide portions (or openings) 103, 104 of the pilot SI joint opening 100, i.e., cross-sectional shape thereof, define cross-sectional areas of the sacrum and ilium guide portions 103, 104 (denoted “A2i-1” and “A2i-2”, respectively).[000378] According to the invention, the sacrum and ilium guide portions 103, 104 can comprise various configurations, e.g., cross-sectional shapes, and sizes to accommodate insertion of a SI joint prosthesis of the invention therein and transition of the sacrum and ilium guide portions 103, 104 from pilot or first configurations and sizes to expanded second configurations and sizes when a SI joint prosthesis is inserted therein.[000379] According to the invention, the sacrum and ilium guide portions 103, 104 can also be disposed at various locations in the sacrum 2 and ilium 4, such as shown in Figs. 17A and 17B, to accommodate desired placement of a SI joint prosthesis in the dysfunctional SI joint.Prosthesis Deployment Assembly[000380] As indicated above, in a preferred embodiment of the invention, the systems for stabilizing dysfunctional SI joints further comprise a prosthesis deployment assembly configured and adapted to engage the SI joint prosthesis and advance the SI joint prosthesis into a pilot SI joint opening created by the drill guide assembly and, thereby, the dysfunctional SI joint.[000381] Referring now to Figs. 18A - 18G, there is shown a preferred embodiment of a prosthesis deployment assembly of the invention (denoted “600”).[000382] As illustrated in Figs. 18A - 18C, the prosthesis deployment assembly 600 comprises an elongated guide member 651 comprising proximal and distal ends 652, 654.[000383] As further illustrated in Figs. 18B and 18E, the elongated guide member 651 further comprises a prosthesis guide pin 656 that extends from the guide member distal end 654. As discussed in detail below and shown in Fig. 18G, the prosthesis guide pin 656 is preferably sized and configured to seat in an internal prosthesis lumen 86a or 86b of SI joint prosthesis 70a (and SI joint prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i).[000384] As illustrated in Figs. 18A, 18D and 18E, the elongated guide member 651 further comprises an internal lumen 658 that extends from the proximal end 652 of the elongated guide member 651 to the distal end 654 of the elongated guide member 651.[000385] As illustrated in Fig. 18G, in a preferred embodiment of the invention, the internal lumen 658 is sized and configured to receive the prosthesis engagement rod 660 (i.e., prosthesis engagement means) of the prosthesis deployment assembly 600, discussed below.[000386] Referring now to Fig. 18F, there is shown a preferred embodiment of a prosthesis engagement rod 660 of the invention. As illustrated in Fig. 18F, the prosthesis engagement rod 660 comprises a proximal end 662 and a threaded distal end 664, which, as discussed in detail below, is sized and configured to threadably engage an internal prosthesis engagement member lumen of a prosthesis of the invention, e.g., internal prosthesis lumens 86a and / or 86b of prosthesis 70a (and SI joint prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i).[000387] As further illustrated in Fig. 18F, in a preferred embodiment, the proximal end 662 of the prosthesis engagement rod 660 comprises a knurled configuration to facilitate threading the prosthesis engagement rod 660 into an internal prosthesis lumen of a SI joint prosthesis of the invention.[000388] Referring back to Figs. 18A and 18B, to further facilitate threading the prosthesis engagement rod 660 into an internal prosthesis lumen of a SI joint prosthesis of the invention, in a preferred embodiment, the elongated guide member 651 further comprises an access port 657 that provides access to the knurled proximal end 662 of the prosthesis engagement rod 660 when positioned in the internal lumen 658 of the elongated guide member 651, as shown in Fig. 18G.Prosthesis Extraction Assembly[000389] As indicated above, in a preferred embodiment of the invention, the systems for stabilizing dysfunctional SI joints further comprise a prosthesis extraction assembly configured and adapted to engage a SI joint prosthesis and remove the SI joint prosthesis from the dysfunctional SI joint.[000390] Referring now to Figs. 19A-19G, there is shown a preferred embodiment of a prosthesis extraction assembly 700 of the invention with SI joint prosthesis 70a connected thereto.[000391] As illustrated in Fig. 19A, the prosthesis extraction assembly 700 generally comprises prosthesis extraction rods or screws 702a, 702b, an extraction fork 710 and a slap hammer assembly 720.[000392] As illustrated in Figs. 19A-19C, the prosthesis extraction rods 702a, 702b comprise elongated rod members 705 comprising capped proximal ends 704a and threaded distal ends 704b, which, in the illustrated embodiment, are sized and configured to threadably engage threaded internal prosthesis lumens 86a, 86b of the SI joint prosthesis 70a (and SI joint prostheses 70b, 70c, 70d, 70e, 70f, 70g, 70h and 70i of the invention).[000393] As illustrated in Figs. 19D-19F, the extraction fork 710 comprises proximal and distal ends 714a, 714b, a primary recess 712 and secondary recesses 715 proximate the distal end 714b. The extraction fork 710 further comprises a threaded lumen 716 proximate the proximal end 714a, which, as discussed below, is sized and configured to threadably engage the threaded distal end 724b of the elongated rod member 721 of the slap hammer assembly 720 discussed below.[000394] As illustrated in Fig. 19A, in a preferred embodiment, the secondary recesses 715 of the extraction fork 710 are configured to receive and releasably engage or ensnare the capped proximal ends 704a of the prosthesis extraction rods 702a, 702b.[000395] As further illustrated in Fig. 19A, the extraction fork 710 is further configured to releasably engage the threaded distal end 724b of the slap hammer assembly 720 via the threaded lumen 716.[000396] As illustrated in Figs. 19A and 19G, the slap hammer assembly 720 comprises a handle 722, the elongated rod member 721, a weighted sleeve member 726 and a bump stop 728. [000397] As illustrated in Fig. 19G, the elongated rod member 721 comprises a proximal end 724a, comprising internal threads 725, and a threaded distal end 724b.[000398] As further illustrated in Fig. 19G, the handle 722 comprises threaded distal end 723, which, as illustrated in Fig. 19A, is sized and configured to threadably engage the proximal end 724a of the elongated rod member 721.[000399] As illustrated in Fig. 19A, the threaded distal end 723 of the handle 722 is further sized and configured to receive and seat the bump stop 728 thereon, wherein the bump stop 728 is securely positioned between the handle 722 and elongated rod member 721 when the handle 722 is engaged to the elongated rod member 721.[000400] In a preferred embodiment, the weighted sleeve member 726 is configured to slidably translate along the elongated rod member 721 and abut the proximal end 714a of the extraction fork 710 and bump stop 728 when the slap hammer assembly 720 is releasably engaged to the extraction fork 710.[000401] According to the invention, removal of prosthesis 70a (and prostheses 70b, 70c, 70d, 70e, 70g, 70h and 70i of the invention) from the expanded post-prosthesis insertion SI joint opening is achieved as follows:• the prosthesis extraction rods 702a, 702b are initially connected to the SI joint prosthesis; and• after the prosthesis extraction rods 702a, 702b are connected to the prosthesis, the surgeon grips the handle 722 of the prosthesis extraction assembly 700 and forcibly abuts the handle 722 against the bump stop 728, wherein a removal or extraction force is exerted on prosthesis via the prosthesis extraction rods 702a, 702b and the prosthesis is released from the expanded post-prosthesis insertion SI joint opening.Image Capture Apparatus[000402] In some embodiments of the invention, the system for stabilizing dysfunctional SI joints further comprises an image capture apparatus configured and adapted to capture images reflecting positions and / or orientations of the elongated guide probe and / or drill guide assembly and / or SI joint prostheses of the invention when disposed in the body, and, particularly, during advancement of a SI joint prosthesis toward and into the dysfunctional SI joint.[000403] According to the invention, suitable image capture apparatus comprise a fluoroscope, a CT system, an ultrasound system, a radiography system, and a magnetic resonance imaging system.EXAMPLES[000404] The following examples are provided to enable those skilled in the art to more clearly understand and practice the present invention. The examples should not be considered as limiting the scope of the invention, but merely as representative thereof.Example 1[000405] An adult male patient, age 55, presented with significant pain proximate his right SI joint. The patient had previously presented with a traumatic injury to the SI joint and a surgical dowel member was implanted in the dysfunctional SI joint to stabilize the SI joint.[000406] A CT scan was performed to determine the basis for the patient’s pain and check for any SI joint abnormalities. The CT scan, which is shown in Fig. 15, indicated that the surgical dowel member (denoted “SD”) had become dislodged and the SI joint was unstable and, hence, causing the pain that the patient was experiencing.[000407] A stabilization procedure was thus performed to stabilize the patient’s dysfunctional SI joint. The specifics of the procedure were as follows:SI Joint Prosthesis[000408] The SI joint prothesis selected for the procedure was similar to prosthesis 70b illustrated in Figs. 5A and 5B, and described in detail above.[000409] The prosthesis included a bone graft material, which was placed in the elongated sections of the prosthesis.Incision[000410] An incision was placed along the lateral lip of the posterior third of the iliac crest to the posterior superior spine to provide a prosthesis entry point into the dysfunctional SI joint.Creation of Pilot SI Joint Opening[000411] A pilot opening was created in the SI joint with the drill guide assembly described above. The bone dislodging apparatus of the assembly comprised a drill assembly and associated drill bit.[000412] The pilot opening that was created in the dysfunctional SI joint was similar to pilot SI joint opening 100 described above.Prosthesis Placement in SI Joint[000413] The SI joint prosthesis was advanced into the dysfunctional SI joint in a posterior trajectory toward the mid-point of the SI end plate and the sacral promontory.[000414] The SI joint prothesis was positioned in the dysfunctional SI joint with the surgical dowel member (“SD”) disposed between and substantially parallel to the elongated members of the prosthesis, and approximately 5.0 mm (“d”) from the central region of the bridge section, as illustrated in Fig. 13.Post-Procedure Assessment[000415] Three (3) months after the joint stabilization procedure, the patient was evaluated by a specialist. CT scan images of the patient’s SI joint were taken. A series of post procedure tests were also performed to determine the stability of the SI joint and mobility of the musculoskeletal structures of the pelvic and lumbar regions proximate the SI joint.[000416] The CT scans reflected (i) secure and proper placement of the SI joint prosthesis in the SI joint, (ii) substantial solid bridging of osseous tissue, and, hence, bone across the SI joint and, (iii) substantial ossification around the prosthesis.[000417] The post procedure tests were also very favorable. The patient tested positive to the flexion abduction and external rotation (FABER) test. The patient also responded very favorably to Gaenslen’s, thigh thrust, compression and distraction tests.[000418] The tests thus confirmed that the SI joint was stabilized and that the musculoskeletal structures of the pelvic and lumbar regions proximate thereto were restored to a near normal level.Example 2[000419] An adolescent female patient, age 13, presented with scoliosis of the spine characterized by a curvature in the spine greater than 40.0°. The patient, who was a candidate for a posterior multilevel spinal fusion surgery procedure, underwent a posterior multilevel spinal fusion procedure, which included two (2) sacral -alar iliac (S2AI) screws that were placed in the left and right SI joints to stabilize the joint in conjunction with two (2) surgical rods and a series of pedicle screws.[000420] Twelve (12) weeks after the procedure the patient complained of lower back pain proximate to a SI joint.[000421] A CT scan was performed to determine the basis for the patient’s pain and check for any SI joint abnormalities. The CT scan indicated that the sacral -alar iliac (S2AI) screw in the right SI joint was dislodged, and the SI joint was dysfunctional and unstable and, hence, likely causing the pain that the patient was experiencing.[000422] A stabilization procedure was thus similarly performed to stabilize the patient’s dysfunctional SI joint.Prosthesis[000423] The SI joint prothesis selected for the procedure was similar to prosthesis 70f illustrated in Figs. 9A and 9B, and described in detail above.Incision[000424] An incision was similarly placed along the lateral lip of the posterior third of the iliac crest to the posterior superior spine to provide a prosthesis entry point into the right SI joint through the posterior ligaments at approximately the S3 level.Creation of Pilot SI Joint Opening[000425] A pilot opening was created in the dysfunctional SI joint with the drill guide assembly described above. The pilot SI joint opening was similar to pilot SI joint opening 100 described above.Prosthesis Placement in SI Joint[000426] The SI joint prosthesis was advanced through the incision and into the dysfunctional SI joint in a posterior trajectory toward the mid-point of the SI end plate and the sacral promontory.[000427] The SI joint prothesis was positioned in the SI joint with the S2AI screw (denoted “SS”) disposed between and substantially parallel to the elongated members of the prosthesis, and between the top and bottom bridge sections, as illustrated in Fig. 14.Post-Procedure Assessment[000428] Four (4) months after the joint stabilization procedure, the patient was evaluated by a specialist. CT scan images of the patient’s SI joint were similarly taken. A series of post procedure tests were also performed to determine the stability of the SI joint and mobility of the musculoskeletal structures of the pelvic and lumbar regions proximate the SI joint.[000429] The CT scans similarly reflected (i) secure and proper placement of the SI joint prosthesis in the SI joint, (ii) substantial solid bridging of osseous tissue, and, hence, bone across the SI joint and, (iii) substantial ossification around the prosthesis.[000430] The post procedure tests were similarly very favorable. The patient also tested positive to the flexion abduction and external rotation (FABER) test, and responded very favorably to Gaenslen’s, thigh thrust, compression and distraction tests.[000431] The tests thus confirmed that the SI joint was stabilized and that the musculoskeletal structures of the pelvic and lumbar regions proximate thereto were restored to a near normal level.[000432] As will readily be appreciated by one having ordinary skill in the art, the present invention provides numerous advantages compared to prior art methods and apparatus for stabilizing dysfunctional SI joints. Among the advantages are the following:• the provision of improved SI joint stabilization systems and apparatus, which can be readily employed in minimally-invasive SI joint stabilization procedures to stabilize dysfunctional SI joints via a posterior approach;• the provision of improved SI joint prostheses, which, when implanted in a dysfunctional SI joint, effectively ameliorate pain associated with the SI joint dysfunction;• the provision of improved SI joint prostheses, which can readily be employed in minimally- invasive SI joint stabilization procedures and provide secure engagement to SI joint structures;• the provision of improved SI joint prostheses, which can readily be employed in minimally- invasive SI joint stabilization procedures and provide supplemental stabilization of SI joint structures with prior implants, such as a sacral-alar iliac (S2AI) screw or surgical dowel member;• the provision of improved SI joint prostheses, which can readily be employed in conjunction with surgical or orthopedic pins, dowels and screws to provide enhanced stabilization of SI joint structures;• the provision of improved SI joint prostheses, which can readily be employed in minimally- invasive SI joint stabilization procedures and possess optimal structural properties to effectively stabilize dysfunctional SI joints; and• the provision of improved SI joint prostheses, which can readily be employed in minimally- invasive SI joint stabilization methods and facilitate remodeling of damaged osseous tissue and regeneration of new osseous tissue and osseous tissue structures.[000433] Without departing from the spirit and scope of this invention, one of ordinary skill can make various changes and modifications to the invention to adapt it to various usages and conditions. As such, these changes and modifications are properly, equitably, and intended to be, within the full range of equivalence of the following claims.

Claims

CLAIMSWhat is claimed is:

1. An apparatus for stabilizing a dysfunctional sacroiliac (SI) j oint, the dysfunctional SI joint comprising a sacrum bone structure, an ilium bone structure and an intraarticular region disposed between the sacrum bone structure and the ilium bone structure, the apparatus comprising: a monolithic member configured and adapted to be advanced into said dysfunctional SI joint in a posterior trajectory, wherein said monolithic member transfixes said dysfunctional SI joint, said monolithic member comprising a first elongated section, a second elongated section and a bridge section, said bridge section disposed between said first elongated section and said second elongated section, wherein said monolithic member comprises a first interface of said bridge section and said first elongated section and a second interface of said bridge section and said second elongated section, said bridge section not extending beyond said first elongated section and said second elongated section in a longitudinal direction, said first elongated section configured to be advanced into said sacrum bone structure when said monolithic member is said advanced into said dysfunctional SI joint in said posterior trajectory, said first elongated section comprising a first central longitudinal axis, a first open proximal end, a first distal end and a first tapered region disposed on said first distal end, said second elongated section configured to be advanced into said ilium bone structure of said dysfunctional SI joint when said apparatus is said advanced into said dysfunctional SI joint in said posterior trajectory, said second elongated section comprising a second central longitudinal axis, a second open proximal end, a second distal end and a second tapered region disposed on said second distal end, said first elongated section and said second elongated section defining a monolithic member plane that intersects and is coincident with said first central longitudinal axis of said first elongated section and said second central longitudinal axis of said second elongated section,said bridge section adapted to be advanced into said intraarticular region of said dysfunctional SI joint when said monolithic member is said advanced into said dysfunctional SI joint in said posterior trajectory, wherein said bridge section traverses said sacrum bone structure, said intraarticular region and said ilium bone structure of said dysfunctional SI joint, said bridge section comprising an offset structure, said offset structure being offset from said monolithic member plane in a first vertical direction, said bridge section extending from said first open proximal end to said first distal end of said first elongated section and from said second open proximal end to said second distal end of said second elongated section, said bridge section further comprising a first proximal end, a third distal end and a third tapered region disposed on said third distal end.

2. The apparatus of Claim 1, wherein said offset structure of said bridge section comprises a planar shape.

3. The apparatus of Claim 1, wherein said offset structure of said bridge section comprises a shape selected from the group consisting of a V-shape, a U-shape and an arcuate shape.

4. The apparatus of Claim 3, wherein said bridge section extends beyond said first interface of said bridge section, said first elongated section, said second interface of said bridge section and said second elongated section in said first vertical direction.

5. The apparatus of Claim 1, wherein said bridge section comprises an elongate opening disposed between said first proximal end of said bridge section and said third distal end of said bridge section and extending through said bridge section.

6. The apparatus of Claim 1, wherein said first elongated section of said monolithic member further comprises a first plurality of slots.

7. The apparatus of Claim 6, wherein said first elongated section of said monolithic member further comprises a first internal lumen in communication with said first open proximal end and said first plurality of slots of said first elongated section, said first internal lumen adapted to receive a first osteogenic composition therein.

8. The apparatus of Claim 1, wherein said second elongated section of said monolithic member further comprises a second plurality of slots.

9. The apparatus of Claim 8, wherein said second elongated section of said monolithic member further comprises a second internal lumen in communication with said second open proximal end and said second plurality of slots of said second elongated section, said second internal lumen adapted to receive a second osteogenic composition therein.

10. The apparatus of Claim 1, wherein said first elongated section and said second elongated section comprise unequal lengths.

11. An apparatus for stabilizing a dysfunctional sacroiliac (SI) j oint, the dysfunctional SI joint comprising a sacrum bone structure, an ilium bone structure and an intraarticular region disposed between the sacrum bone structure and the ilium bone structure, the apparatus comprising: a monolithic member configured and adapted to be advanced into said dysfunctional SI joint in a posterior trajectory, wherein said monolithic member transfixes said dysfunctional SI joint, said monolithic member comprising a first elongated cylindrical shaped section, a second elongated cylindrical shaped section and a bridge section, said bridge section disposed between said first elongated section and said second elongated section and not extending beyond said first elongated section and said second elongated section in a longitudinal direction, said first elongated cylindrical shaped section configured to be advanced into said sacrum bone structure when said monolithic member is said advanced into said dysfunctional SI joint in said posterior trajectory, said first elongated cylindrical shaped section comprising a first open proximal end, a first distal end and a first tapered region disposed on said first distal end, said second elongated cylindrical shaped section configured to be advanced into said ilium bone structure when said monolithic member is said advanced into said dysfunctional SI joint in said posterior trajectory, said second elongated cylindrical shaped section comprising a second open proximal end, a second distal end and a second tapered region disposed on said second distal end, said bridge section adapted to be advanced into at least said intraarticular region of said SI joint when said monolithic member is said advanced into said dysfunctional SI joint in said posterior trajectory, wherein said bridge section traverses said sacrum bone structure, said intraarticular region and said ilium bone structure of said dysfunctional SI joint,said bridge section comprising a first proximal end and a third distal end disposed opposite said first proximal end, said bridge section comprising an open bridge structure comprising a top bridge member and a separate bottom bridge member, said top bridge member and said bottom bridge member defining an open region between said top bridge member and said bottom bridge member, said monolithic member comprising a first interface of said top bridge member at a first top region of said first elongated cylindrical shaped section and a second interface of said top bridge member at a second top region of said second elongated cylindrical shaped section, said first interface and said second interface being spaced a first distance apart, and a third interface of said bottom bridge member and at a first bottom region of said first elongated cylindrical shaped section and a fourth interface of said bottom bridge member at a second bottom region of said second elongated cylindrical shaped section, said third interface and said fourth interface being spaced a second distance apart, said top bridge member comprising a second proximal end, a fourth distal end, a first elongate opening disposed between said second proximal end and said fourth distal end, and a third tapered region disposed on said fourth distal end, said bottom bridge member comprising a third proximal end, a fifth distal end, a second elongate opening disposed between said third proximal end and said fifth distal end, and a fourth tapered region disposed on said fifth distal end.

12. The apparatus of Claim 11, wherein said top bridge member and said bottom bridge member comprise a corresponding shape selected from the group consisting of a partial rectangular shape, a V-shape and a U-shape.

13. The apparatus of Claim 11, wherein said top bridge member extends beyond said first interface of said top bridge member and said first elongated cylindrical shaped section and said second interface of said top bridge member and said second elongated cylindrical shaped section in a first vertical direction, and said bottom bridge member extends beyond said third interface of said bottom bridge member and said first elongated cylindrical shaped section and said fourth interface of said bottom bridge member and said second elongated cylindrical shaped section in a second vertical direction.

14. The apparatus of Claim 11, wherein said first elongated cylindrical shaped section of said monolithic member further comprises a first plurality of slots.

15. The apparatus of Claim 14, wherein said first elongated cylindrical shaped section further comprises a first internal lumen in communication with said first open proximal end and said first plurality of slots of said first elongated cylindrical shaped section.

16. The apparatus of Claim 11, wherein said second elongated cylindrical shaped section of said monolithic member further comprises a second plurality of slots.

17. The apparatus of Claim 16, wherein said second elongated cylindrical shaped section further comprises a second internal lumen in communication with said second open proximal end and said second plurality of slots of said second elongated cylindrical shaped section.

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