Abstract:
An implantable device including a tapered body having a sidewall, an internal cavity, a first end, and a second end, the sidewall including a frusto-conical inner surface extending from the first end to the second end, the first end including a first end opening and the second end including a second end opening, a first side opening extending through the sidewall, a second side opening extending through the sidewall, the second side opening arranged diametrically opposite the first side opening, an external thread arranged helically about a central longitudinal axis of the tapered body, the external thread having a continuously decreasing outer diameter along the tapered body, a first ancillary member operatively arranged to be inserted through the first end opening and then the first or second side opening, and a second ancillary member operatively arranged to be inserted through the first end opening and then the first or second side opening.

Description:
FIELD OF THE INVENTION 
     The present disclosure broadly relates to medical devices for the treatment of musculoskeletal disorders and, more particularly, to surgical implantable devices, which facilitate bone growth. Even more particularly, the invention relates to a percutaneous surgical implant, which is secured to the sacroiliac joint, and a method for inserting and securing the same. 
     BACKGROUND OF THE INVENTION 
     Sacroiliac (SI) joints are formed by the connection of the sacrum to the ilium bones of the pelvis. There are two SI joints in the human body; one on the left and right sides, respectively of the lower spine. Sacroiliac joints are diarthrodial, meaning they allow motion between the bones they connect. Additionally, SI joints are weight bearing, meaning a primary function of the joint is to absorb shock and provide just enough motion and flexibility to lessen stress on the pelvis and spine. In women, the SI joints are weaker, in part, probably, because the SI joints relax during the end stages of parturition, or childbirth. The joints can become painful for a number of reasons including, but not limited to, arthritis, abnormal leg alignment, pregnancy leading to increased stress on the joints, or any condition which alters the normal walking pattern and/or stresses the joints including trauma, infection, cancer, and spinal instability. In the early 1900&#39;s the exact causes of back pain were unknown but, there were a number of possible causes including dysfunction of the SI joint. In 1934, Mixter and Barr proclaimed that back pain could result from a posterior rupture of an intervertebral disc. Mixter W J, Barr J S. “ Rupture of the intervertebral disc with involvement of the spinal canal .” N Engl J Med 1934; 211:210-5. Due to Mixter and Barr&#39;s paper, physicians began to consider degenerative disk disease and disk herniation as the primary causes of back pain over SI joint dysfunction. Today, it is believed that approximately 20% of low back pain is SI joint related. There are a number of misdiagnoses of back pain due to the variety of possible causes. 
     SI joint pain can be treated non-surgically and surgically. One nonsurgical option for pain relief involves the injection of a corticosteroid into the joint, which reduces inflammation of the joint. Another nonsurgical option for pain relief is the use of oral anti-inflammatory medications such as non-steroidal anti-inflammatory drugs (NSAIDS), ibuprofen, and naproxen to reduce inflammation of the painful joint. Physical therapy, yoga, and Pilates can also help relieve pain associated with the SI joint because pain can result from excessive or insufficient motion in the joint. Some patients benefit from wearing a special brace called a sacroiliac belt, which wraps around the hips to hold the SI joint tightly together. This belt can help decrease inflammation of the SI joint. 
     If non-surgical treatments fail to treat the pain associated with the SI joint, the pain can also be treated surgically by fusing the joint(s). This surgical fusion is also known as arthrodesis. In this surgery, the cartilage covering the surfaces of the SI joints is removed and the bones are held together with plates and screws until they grow together, or fuse. Percutaneous sacroiliac joint fusion is a minimally invasive approach in which cages or screws are placed, with or without bone graft, to achieve a fusion. Smooth or threaded metallic bone fastener devices have been used to achieve a fusion and such devices include a series of metallic, porous plasma spray coated rods, which are surgically inserted across the SI joint. Other systems use cannulated screws. 
     One surgical implant of the cannulated screw type, found in U.S. Pat. No. 8,142,503 (Malone), has been developed, which comprises a conical hollow facet for facilitating bone growth or repair. The conical hollow facet further comprises threading for facilitating securement to bone, a port to accommodate an allen wrench, an internal cavity for bone morphogenic protein, and a plurality of orifices for facilitating delivery of the substance within the cavity to adjacent bony structures. The facet disclosed also includes a member, which seals the hollow cavity to prevent desired substances from escaping from within the cavity. This reference fails to disclose an open-ended surgical implant having apertures for ancillary screws. 
     Another surgical implant is disclosed in the Michelson family of patents (U.S. Pat. No. 6,558,423; U.S. Pat. No. 7,033,394; U.S. Pat. No. 7,041,135). The implant disclosed in the Michelson family of patents comprises a cylindrical perforated hollow body having a leading end and a trailing end, holes for the growth of bone and vascular access, and a constant diameter of the screw threading along the length of the cage. The trailing end of the implant further comprises holes to receive a bone screw such that the bone screw would be directed first through the trailing end and then through either one of upper or lower vertebral bone engaging surfaces of the implant and finally into the vertebral body at an angle. This reference fails to disclose a percutaneous sacroiliac joint fusion implant, which comprises an open-ended tapered screw arranged to receive at least two ancillary screws, which can be tapped to determine the trajectory of the ancillary screws while the ancillary screws are engaged with the tapered screw. 
     United States Patent Application Publication No. 2004/0147929 (Biedermann et al.) discloses yet another surgical implant which comprises a middle conical bone-threading section tapering towards an end and apertures therein which allow for the growing-in of bone material or vessels. This reference fails to disclose an open-ended surgical implant having apertures for ancillary screws. 
     United States Patent Application Publication No. 2011/0230884 (Mantzaris et al.) discloses a polyaxial screw device to be inserted into a bone structure comprising a tapered screw member, which is cylindrical and has a substantially smooth exterior surface, a threaded portion, and tapered apertures to accommodate lag screws. This reference fails to disclose an open-ended surgical implant having apertures for bone fusion promoting substances and apertures for ancillary screws. 
     Despite these attempts, surgical treatment of the SI joint has still been problematic because the joint is very deeply located in a region of the human body. Percutaneous surgical implants used on the SI joint have a high rate of screw malpositions, which may be associated with risk of neurologic damage or inefficient stability. Additionally, over time if the SI joint does not completely immobilize because of a percutaneous surgical implant, the spine can shift, the implants can loosen, and pain can result again. Thus, a need has existed for an accurate and effective surgical implant for the fusion of the SI joint. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention comprises an implantable device comprising a tapered body having a sidewall, an internal cavity, a first end, and a second end, the sidewall comprising a single continuous frusto-conical inner surface extending from the first end to the second end, the first end comprising a first end opening defined by the single continuous frusto-conical inner surface and the second end opening comprising a second end opening defined by the single continuous frusto-conical inner surface, a first side opening extending through the sidewall, a second side opening extending through the sidewall, the second side opening arranged diametrically opposite the first side opening, an external thread arranged helically about a central longitudinal axis of the tapered body, the external thread having a continuously decreasing outer diameter along the tapered body, a first ancillary member operatively arranged to be inserted through the first end opening and then the first or second side opening, and a second ancillary member operatively arranged to be inserted through the first end opening and then the first or second side opening. The invention also includes a method for surgically inserting and securing the implant into the sacroiliac joint, comprising the following steps: drilling a tapered body into the sacroiliac joint, tapping and placing a first ancillary member to either the sacrum or the iliac bone through an open end of the tapered body and through a first opening within the tapered body, and tapping and placing a second ancillary member to either the sacrum or the iliac bone through the open end of the body and through a second opening within the body. The implant provides a number of significant improvements to the techniques already available, among which include a single incision approach to percutaneous fusion of the sacroiliac joint while covering greater surface area of the joint; allowing for a deliverable approach and a visible approach to the fusion process; and, tools to decorticate the joint to allow fusion to occur. 
     The present invention broadly includes an implantable device including a tapered body having a sidewall, an internal cavity, a first end, and a second end, the sidewall including a frusto-conical inner surface extending from the first end to the second end, the first end including a first end opening defined by the frusto-conical inner surface and the second end including a second end opening defined by the frusto-conical inner surface, a first side opening extending through the sidewall, a second side opening extending through the sidewall, the second side opening arranged diametrically opposite the first side opening, an external thread arranged helically about a circumference of the tapered body, the external thread having a continuously decreasing outer diameter along the tapered body, a first ancillary member operatively arranged to extend through and project outwardly through only the first end opening and the first side opening and a second ancillary member operatively arranged to extend through and project outwardly through only the first end opening and the second side opening. 
     The present invention broadly includes a method for inserting and securing an implantable device into a sacroiliac joint of a person, the method including the following steps: making an incision into the sacroiliac joint, inserting a tapered body into the sacroiliac joint, the tapered body including: a sidewall having a frusto-conical inner surface, an internal cavity, a first end having a first end opening, a second end having a second end opening, a first side opening extending through the sidewall, a second side opening extending through the sidewall, the second side opening arranged diametrically opposite the first side opening, an external thread arranged helically about a circumference of the tapered body, the external thread having a continuously decreasing outer diameter along the tapered body, where the frusto-conical inner surface extends from the first end to the second end and the first end opening defined by the frusto-conical inner surface and the second end opening defined by the frusto-conical inner surface, inserting a first ancillary member into and through only the first end opening and the first side opening and securing the first ancillary member to either a sacrum or an iliac bone and inserting a second ancillary member into and through only the first end opening and the second side opening and securing the second ancillary member to either the sacrum or the iliac bone. 
     The present invention broadly includes an implantable device, including a body having a sidewall, an internal cavity, a first end, and a second end, the sidewall comprising an inner surface extending between the first end and the second end, the first end including one and only one opening defined by the inner surface and the second end including one and only one opening defined by the inner surface, a first side opening extending through the sidewall, a second side opening extending through the sidewall, an external thread arranged about a circumference of the body, a first ancillary member operatively arranged to extend through and project outwardly through only the one and only one opening of the first end and the first side opening and a second ancillary member operatively arranged to extend through and project outwardly through only the one and only one opening of the first end and the second side opening. 
     A primary object of the present invention is to provide a safe, accurate, reliable, and minimally invasive method and apparatus for a percutaneous sacroiliac joint fusion. 
     A further object of the present invention is to provide a safe surgical implant for a percutaneous sacroiliac joint fusion, which allows a surgeon to accurately and effectively secure, with flexibility, a fusion-facilitating device. 
     These and other objects and advantages of the present invention will be readily appreciable from the following description of preferred embodiments of the invention and from the accompanying drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention in view of the accompanying drawing figures. 
         FIG. 1  is a rear perspective view of part of the human skeletal system showing the present invention placed in the SI joint; 
         FIG. 2  is a top plan view of the present invention taken along line  2 - 2  in  FIG. 1 , with parts of the human skeletal system removed to better illustrate the invention; 
         FIG. 3  is a detailed view of the present invention as shown in  FIG. 1 ; 
         FIG. 4  is a detailed view of the present invention as shown in  FIG. 2  as the device would appear secured within the SI joint; 
         FIG. 5  is a front view of the present invention; 
         FIG. 6  is an exploded view of the present invention shown in  FIG. 5 ; 
         FIG. 7 a    is a left side view of the present invention as viewed from the left in  FIG. 5 ; 
         FIG. 7 b    is a right side view of the present invention as viewed from the right in  FIG. 5 ; 
         FIG. 8  is a top plan view of the present invention; 
         FIG. 9  is a bottom plan view of the present invention; and, 
         FIG. 10  is a partial cross section view of the present invention taken along line Y-Y in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural root elements of the invention. Moreover, although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of these embodiments, some embodiments of methods, devices, and materials are now described. 
     Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and, as such, may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. It should be appreciated that the term “substantially” is synonymous with terms such as “nearly”, “very nearly”, “about”, “approximately”, “around”, “bordering on”, “close to”, “essentially”, “in the neighborhood of”, “in the vicinity of”, etc., and such terms may be used interchangeably as appearing in the specification and claims. The terms “right” and “left” as they refer to the joints and bones refer to the anatomical right and left as opposed to the right and left from the perspective of a viewer of the patent drawings. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described. 
     The device of the present invention can be made of titanium, alloys of titanium, carbon fiber, bone or ceramic, Polyetheretherketone (hereinafter referred to as “PEEK”), or any material suitable to be tolerated or bio-absorbable by the human body. Additionally, the device may comprise a unitary structure or may be of a multi-piece construction. 
     Furthermore, it should be appreciated that although the preferred embodiment of the present invention takes the form of a percutaneous sacroiliac joint fusion device, the present invention may also take the form of spinal fusion devices, joint stabilizers, bone fixation devices and other orthopedic appliances where bone-to-bone growth or bone-to-bone stabilization is desired. 
     Structure 
     Adverting now to the figures,  FIG. 1  shows percutaneous sacroiliac joint fusion device  10  (hereinafter SI joint fusion device  10 ) of the present invention placed within a partial musculoskeletal representation of the mid-portion of a human. Spine  12  is connected to sacrum  13  and sacrum  13  is arranged between left and right ilium bones  14  and  15 , respectively. Left ilium bone  14  is adjacent sacrum  13  to the left of sacrum  13 . Right ilium bone  15  is adjacent sacrum  13  to the right of sacrum  13 . Left and right femurs  17  and  18  protrude downwardly from the pelvis. Sacroiliac joint  16  (hereinafter SI joint  16 ) is located between right ilium bone  15  and sacrum  13 . It should be appreciated that there is another sacroiliac joint located between left ilium bone  14  and sacrum  13  but, for purposes of illustration, we refer to the right sacroiliac joint herein. SI joint fusion device  10  of the present invention could be used on either the right or the left sacroiliac joints. 
       FIG. 2  shows a top plan view of SI joint fusion device  10  with parts of the body removed along line  2 - 2  in  FIG. 1  to better illustrate the invention. From this view, it is apparent that SI joint  16  is difficult to access for purposes of a percutaneous SI joint fusion. Additionally, it is apparent that the dimensions of SI joint fusion device  10  depend on the length, width and curvature of each SI joint  16  operated upon. Depending upon these parameters, SI joint fusion device  10  may be secured more toward the incision or more toward the end opposite the incision. 
     SI joint fusion device  10  of the present invention is shown in  FIG. 3 , and broadly comprises body  20  and first and second ancillary members  90  and  100 , respectively, protruding outwardly from body  20 . In the preferred embodiment, body  20  is tapered and frusto-conical. However, it should be appreciated that body  20  could be another shape to accommodate SI joint  16 . For example, body  20  could be a non-tapered cone, a cylinder, a tapered cylinder, or a square-based or triangular-based pyramid. Body  20  further comprises first and second apertures  70  and  80 , (detailed below) which receive first and second ancillary members  90  and  100 , respectively. In the preferred embodiment, body  20  has a width in the range of approximately 3.5 mm-4.5 mm. However, it should be appreciated that body  20  can be manufactured to have a smaller or larger width to accommodate smaller or larger SI joints  16 . Additionally, in the preferred embodiment, body  20  is less than 3 cm in length. Similarly, body  20  can be manufactured to have a longer length. First and second ancillary members  90  and  100  pass through first and second apertures  70  and  80 , respectively, through end  40  of body  20 . Body  20  further comprises threading  50  to help secure SI joint fusion device  10  between sacrum  13  and right ilium bone  15 . In the preferred embodiment, threading  50  is helical. However, it should be appreciated, that threading  50  could take any form and need not be continuous. For example, threading  50  could be segmented or threading  50  could comprise a plurality of protrusions. Additionally, body  20  comprises plurality of openings  60  through which fusion-facilitating substances can pass. 
       FIG. 4  is a detailed view of SI joint fusion device  10  as pictured in  FIG. 2 . From this view, body  20  is shown having a taper and a frusto-conical shape. Additionally, threading  50  has a helical shape. The depth of threading  50  can be constant or it can vary. For example, the depth of threading  50  can taper along with the taper of body  20 . Alternatively, the depth of threading  50  can taper in a direction opposite to the taper of body  20 . In the preferred embodiment, the depth of threading  50  tapers along with the taper of body  20 . These tapers are effective in fusing the SI joint  16  because typically, SI joint  16  narrows. Additionally, it should be appreciated that threading  50  could be sharp, rounded, or square. First ancillary member  90  is secured within sacrum  13  and second ancillary member  100  is secured within right ilium bone  15 . 
     In the preferred embodiment, SI joint fusion device  10  is made of PEEK. Nevertheless, it should be appreciated that SI joint fusion device  10  could be made of any suitable material which is highly resistant to thermal degradation and attack by organic and aqueous environments. For example, polytetrafluoroethylene (PTFE) could be an alternative. In the art, PEEK is routinely used for medical implants. 
     Body  20  is open at both ends and includes end  40  and end  45 . As shown in  FIG. 5 , end  40  is disposed at the top end and end  45  is disposed at the bottom end. Body  20  further includes a sidewall extending between end  40  and end  45 . First and second ancillary members  90  and  100 , respectively, are arranged to extend through body  20 . In an example embodiment, the sidewall of body  20  includes an inner surface extending from end  40  to end  45 ; the inner surface of the sidewall may be frusto-conical. In an example embodiment, end  40  is parallel to end  45  and both are planar. In an example embodiment, end  40  includes an opening defined by the inner surface of the sidewall of body  20  and end  45  includes an opening defined by the inner surface of the sidewall of body  20 . In an example embodiment, end  40  and end  45  each includes only a single opening defined by the inner surface of the sidewall of body  20 . In alternate embodiments, these ends could be angled, curved, or segmented. Additionally, end  45  has a smaller diameter than end  40 . End  45  can be of any diameter so long as a Kirschner wire or a k-wire substitute can pass through end  45  and end  45  can be arranged within SI joint  16 . First and second ancillary members  90  and  100  are arranged to protrude outwardly from body  20  through first and second apertures  70  and  80 , respectively. First and second apertures  70  and  80  are arranged within the sidewall of body  20 . When first and second ancillary members  90  and  100  are placed through first and second apertures  70  and  80 , respectively, the heads of first and second ancillary members  90  and  100  are hidden within body  20 . In the preferred embodiment, SI joint fusion device  10  has two apertures  70  and  80  but, in an alternate embodiment, the device could have additional apertures. Additionally, in the preferred embodiment, first aperture  70  is arranged diametrically opposite second aperture  80 , and proximate open end  40 . However, apertures  70  and  80  could be arranged at other points around and along body  20 . 
       FIG. 6  shows the present invention with first and second ancillary members  90  and  100  suspended above body  20 . First and second ancillary members  90  and  100  are typical screws such as, preferably, a Phillips oval head. However, first and second ancillary members  90  and  100  could be a Phillips flat head, a Phillips pan head, a Phillips truss head, a slotted flat, oval, pan, truss head, or any other screw suitable for the present invention. Additionally, first and second ancillary members  90  and  100  are self-tapping screws. In the preferred embodiment, first and second ancillary members  90  and  100  feature threading  95  and  105 . In the preferred embodiment, threading  95  and  105  are single starts, meaning that there is only one ridge wrapped around the cylinders. However, threading  95  and  105  can be double starts, meaning that there are two ridges wrapped around the cylinders of the screws. Similarly, threading  50  is a single start but, it could be a double start. Along these lines, in alternate embodiments, threading  50 ,  95  and  105  can be coarse or fine. Alternatively, first and second ancillary members  90  and  100  could have no threading at all and have some other secure means such as, a rod or a pin. Notably, first and second ancillary members  90  and  100  are not coupled to body  20  both when they are engaged and when they are not engaged with body  20 . This uncoupled state allows a surgeon greater leeway in determining and setting the screw trajectory. 
     First and second ancillary members  90  and  100  are arranged above body  20  at angles α and θ in relation to vertical line Z, which is the longitudinal center line of SI joint fusion device  10 . Preferably, angles α and θ are both within the range of approximately 10 degrees to 80 degrees. However, it should be appreciated that angles α and θ could be any suitable angle so long as the angle ensures an effective securement between SI joint  16  and sacrum  13  and right ilium bone  15 . 
       FIG. 7 a    shows the left side of the present invention shown in  FIG. 5  and  FIG. 7 b    shows the right side of the present invention shown in  FIG. 5 . In  FIG. 7 a   , first ancillary member  90  protrudes from first aperture  70 , which is circular. In  FIG. 7 b   , second ancillary member  100  protrudes from second aperture  80 , which is circular. The diameters of first and second apertures  70  and  80  are larger than the diameters of first and second ancillary members  90  and  100  to accommodate the passage of members  90  and  100 . However, the head portions of first and second ancillary members  90  and  100  are arranged to abut the inner circumferential surfaces of first and second apertures  70  and  80 , respectively, such that they do not pass through. Apertures  70  and  80  could be any size or shape to accommodate first and second ancillary members  90  and  100  so that a surgeon can anchor first and second ancillary members  90  and  100  through apertures  70  and  80 , respectively, to bone while still engaging first and second ancillary members  90  and  100  with body  20 . Apertures  70  and  80  can guide first and second ancillary members  90  and  100 , respectively. However, a surgeon also has a tap available to determine the screw trajectory of first and second ancillary members  90  and  100 . 
     End  40  of SI joint fusion device  10  is visible in  FIG. 8 . Additionally, first and second ancillary members  90  and  100  are visible protruding from underneath end  40  in an outward direction from body  20 . End  45  is arranged approximately at the center of end  40  at the opposite end of body  20 . In the preferred embodiment, end  40  is circular. Thus, end  45  is arranged at the origin, or center, of end  40  at the opposite end of body  20 . In an alternate embodiment, end  45  can be arranged off center of end  40 . Similarly, in an alternate embodiment, end  40  could be rectangular, triangular, or another shape to accommodate first and second ancillary members  90  and  100  and a wire extending through body  20 . End  45  is circular in the preferred embodiment but, end  45  can be another shape to accommodate the passage of a wire. Threading  50  is not visible from this view because of the taper of body  20 . Apertures  60  are visible from the inside of body  20 . 
     At the other end,  FIG. 9  shows tapered end  45 , threading  50 , plurality of apertures  60 , and ancillary members  90  and  100  of SI joint fusion device  10 . The heads of first and second ancillary members  90  and  100  are resting within body  20  on the inside of first and second apertures  70  and  80 , respectively, and thus, are not visible. Second ancillary member  100  is shown protruding outward from body  20  and upward in relation to horizontal line X. Horizontal line X is not part of the present invention. Instead, horizontal line X is used to illustrate that first and second ancillary members  90  and  100  can be tilted or angled within first and second apertures  70  and  80 , respectively, to achieve an effective fusion. 
     A partial cross-section of the present invention is shown in  FIG. 10 . First and second ancillary members  90  and  100  are not cut and visible as fully-intact as shown in  FIG. 5 . First and second ancillary members  90  and  100  are arranged at angles α and θ within first and second apertures  70  and  80 , respectively, of body  20 . When first and second ancillary members  90  and  100  are fully placed within first and second apertures  70  and  80 , respectively, of body  20 , the head portions of first and second ancillary members  90  and  100  abut the inner surface of the sidewall of body  20  and first and second apertures  70  and  80 . First ancillary member  90  is operatively arranged to be inserted through end  40  and first aperture  70 . Second ancillary member  100  is operatively arranged to be inserted through end  40  and second aperture  80 . In an example embodiment, end  40  includes an opening defined by the frusto-conical inner surface of the sidewall of body  20 . In the preferred embodiment, openings  60  are distributed equally along the length of body  20 . However, it should be appreciated that plurality of openings  60  can be distributed along body  20  in any way. In the preferred embodiment, there are at least eight openings  60 . From this partial cross section view, there are approximately half the number of plurality of openings  60 , which are visible. It should be appreciated there could be any number of openings  60  in alternate embodiments. 
     Function 
     SI joint fusion device  10  is typically used in a minimally invasive percutaneous fusion of SI joint  16 . After placing the patient in position and under anesthesia for surgery, a surgeon designates an ideal incision point and direction under image intensifier control. Then, an incision is made to access SI joint  16  and a guide wire is placed percutaneously and advanced across SI joint  16 . Preferably, the incision is made along the dimple of Venus. The cartilaginous end plates of SI joint  16  are removed and a hole is drilled across SI joint  16 . Then, SI joint fusion device  10  is advanced over the guide wire until it is located in SI joint  16 . The ends of body  20  allow a surgeon to extend a wire, preferably a K-wire, through end  40 , hollow cavity  30  of body  20 , and end  45 . Optionally, SI joint fusion device  10  is guided within a guide tube to protect the surrounding soft tissue. Thereafter, a surgeon removes the guide wire and drills holes under fluoroscopic guidance for placement of ancillary screw members  90  and  100  into right ilium bone  15  and sacrum  13 . Once the holes are drilled, a surgeon taps and places ancillary screw members  90  and  100 , respectively, into right ilium bone  15  and sacrum  13 , respectively. In the preferred embodiment, ancillary screw members  90  and  100  are placed at angles α and θ which are as close to 80 degrees as possible in relation to vertical line Z. The greater the angle between ancillary screw members  90  and  100  and body  20 , the more secure SI joint fusion device  10  is in effectively immobilizing SI joint  16 . After ancillary screw members  90  and  100  are placed, respectively, hollow cavity  30  of body  20  is optionally, filled with bone graft. Preferably, a surgeon fills SI joint fusion device  10  with demineralized bone matrix, bone morphogenetic protein type 2, or autograft. Once SI joint fusion device  10  is positioned satisfactorily, the surgeon tightens ancillary screw members  90  and  100 , respectively. SI joint fusion device  10  promotes the arthrodesis or fusion process. 
     Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention. 
     REFERENCE NUMERALS 
     
         
           10  percutaneous sacroiliac joint fusion device 
           12  spine 
           13  sacrum 
           14  left ilium bone 
           15  right ilium bone 
           16  sacroiliac joint 
           17  left femur 
           18  right femur 
           20  body 
           30  internal cavity 
           40  end 
           45  end 
           50  threading 
           60  plurality of openings 
           70  first aperture 
           80  second aperture 
           90  first ancillary member 
           95  first ancillary member threading 
           100  second ancillary member 
           105  second ancillary member threading 
         θ first angle 
         α second angle 
         Z central longitudinal axis 
         X horizontal line