Abstract:
An apparatus and method for minimally invasive stabilization of anterior pelvic fractures consisting of two rod shaped implants that may be surgically inserted subcutaneously or along the bone surface of each hemipelvis and a means of both linking the individual rods as well as rigidly securing the construct to the pelvis.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/856,610 filed Nov. 6, 2006. 
    
    
     BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     This invention relates to an implantable plate and/or rod system and its associated hardware used for the operation of implantation that is utilized to stabilize pelvic fractures. 
     2. Description of the Prior Art 
     Devices used to treat fracture of the pelvis currently fall under two general classifications; internal fixation and external fixation. Internal fixation is typically utilized when the patient exhibits unstable posterior pelvic fractures. See, for example, U.S. Pat. Nos. 4,454,876; 5,108,397; 6,340,362 and 6,440,131. This type of fracture tends to be more complex with it involving multiple bony structures. Internal fixation addresses these clinical issues through open reduction and correction of misaligned bone segments that are subsequently stabilized with a wide variety of plate and screw methods. 
     Anterior pelvic fractures or hemodynamically unstable patients are candidates for external fixation. See, for example, U.S. Pat. Nos. 4,292,964; 4,361,144; 5,350,378 and 6,162,222. External fixation consists of stabilizing the pelvic ring with a rigid framework residing outside the patient&#39;s body that is connected to the patient&#39;s pelvis via multiple pins that penetrate through the patient&#39;s soft and hard tissues. Several frame types are currently utilized. Two of the more widely deployed devices for external pelvic stabilization are the Hoffmann 2 Inverted “A” Frame and the Ganz Pelvic C Clamp. 
     The application of external reduction and fixation for pelvic fractures is advantageous compared to internal reduction and fixation due to its speed of deployment and lower level of technical training required for utilization. The primary disadvantages of external fixation of pelvic fractures include high risk of pin tract infections, general patient discomfort with external frame, physically blocks subsequent surgery on the abdomen and difficult to fit obese patients. The disclosed system maintains many of the advantages of external fixation while eliminating the previously associated disadvantages. 
     It is the goal of the disclosed invention to provide a surgical hardware system that will allow for submuscular or supramuscular/subcutaneous internal fixation of anterior pelvic instability through a minimally invasive surgical approach. 
     BRIEF SUMMARY OF THE INVENTION 
     It is herein disclosed a method for stabilization of anterior pelvic fractures consisting of an orthopedic hardware system that may be positioned between the skin and the muscle of the patient&#39;s lower torso or alternatively along the pelvic bone surface and a series of attachment devices that rigidly fix said hardware system to the bony structures of the patient&#39;s pelvis. In its preferred embodiment, the hardware system consists of two elongated members that when joined together form a framework that encompasses the anterior elements of the pelvis. 
     The design and curvature of the two elongated members is such so as to facilitate their insertion and advancement between the skin and the muscle of the patient&#39;s lower torso or along the bony surface of the pelvis. The elongated members may also contain contours so as to ensure clearance of critical anatomical features located within the inguinal canal such as the femoral nerve, artery and vein. The location of elongated member&#39;s insertion is either over each of the patient&#39;s anterior inferior iliac spine prominences or iliac crest. The surgeon then slides the elongated member around the anterior portion of the pelvis. The depth of the elongated member during advancement is subcutaneous and supramuscular or submuscular. Elongated member advancement is complete when the distal end of the device is positioned above the patient&#39;s pubis. Elongated members are inserted from both right and left sides. 
     The elongated members may be in the general shape of rods or plates. In one embodiment, the right and left elongated members are linked over the patient&#39;s pubic symphysis by way of interlocking ends and multiple screw or pin placement. An alternative embodiment links the two elongated members together at the pubis through application of a clamp device that accepts both device ends. Another alternative embodiment links the elongated member ends via a progressive interlocking produced by spring-loaded tabs along the male component engaging cut-out slots along the female component. A further embodiment links the two device halves through a cable driven screw advancement. A final embodiment links the two device halves through attachment of a cable linking the two medial ends of the anchored plates and external tensioning of the cable. 
     Device stabilization to the pelvis is obtained through insertion of multiple screws or pins through the lateral device ends and into the bone of the anterior inferior iliac spine or iliac crest. Additional fixation of the device to the pelvis may be obtained through insertion of multiple screws or pins through the clamp connecting means and into the underlying bone of the pubis region. Manipulation of the pelvic halves to obtain fracture reduction and plate joining may be accomplished through external loading applied via Schanz pins placed in the lateral portion of each plate half. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1 . Female Plate Component of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic Stabilization System. Shown is a drawing of the female plate components of the Less Invasive Pelvic Stabilization System. 
         FIG. 2 . Male Plate Component of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic Stabilization System. Shown is a drawing of the male plate components of the Less Invasive Pelvic Stabilization System. 
         FIGS. 3A-3B . Male and Female Component of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic Stabilization System. Shown is a drawing of the male and female components of the Less Invasive Pelvic Stabilization System joined together in a configuration as would be utilized clinically. 
         FIG. 4 . Close-up of the interlocking components of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic Stabilization System. Shown is a drawing of the male and female plate components prior to joining. 
         FIG. 5 . Close-up of the interlocking components of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic. Stabilization System in a fully interlocked configuration. 
         FIG. 6 . Close-up of the interlocking components of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic Stabilization System in a slightly less than fully interlocked configuration. 
         FIG. 7 . Close-up of the interlocking components of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic Stabilization System in an interlocked configuration that is one-half of fully interlocked. 
         FIG. 8 . Close-up of the interlocking components of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic Stabilization System in a minimally interlocked configuration. 
         FIGS. 9A-9F . Shown is the female component of the Spring Ratcheting Less Invasive Pelvic Stabilization System. 
         FIGS. 10A-10F . Shown is the male component of the Spring Ratcheting Less Invasive Pelvic Stabilization System. 
         FIGS. 11A-11C . Shown is the release clamp used to disengage the male and female plate components of the Spring Ratcheting Less Invasive Pelvic Stabilization System. 
         FIGS. 12A-12D . Shown is the Cable Driven Invasive Pelvic Stabilization System. 
         FIGS. 13A-13F . Shown is the female component of the Thread and Screw Driven Less Invasive Pelvic Stabilization system. 
         FIGS. 14A-14B . Shown is the male component of the Thread and Screw Driven Less Invasive Pelvic Stabilization system. 
         FIG. 15 . Shown is a clinically usable positioning of a Clamp Adjusted Less Invasive Pelvic Stabilization system on a human pelvis. 
         FIG. 16A . Shown is a clinically usable positioning of a Clamp/Plate Less Invasive Pelvic Stabilization system on a human pelvis. 
         FIG. 16B . Shown is an expanded view of the medial segment for an alternative configuration of the Clamp/Plate Less Invasive Pelvic Stabilization system. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates the female plate components of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic Stabilization System. The device is a smoothly arching, circular rod  100  made from typical metallic materials common to orthopedic devices such as stainless steel and titanium alloys. The medial end  108  of the device  100  expands to a radius  103  greater than that of the remaining rod section  100  to allow interconnection with the male component of the plate system. At the medial end  108  of the female plate, a circular opening  101  leading to a hollow section within the rod  100  allows the male plate to interconnect with the female plate. Multiple screw holes  102  run through the hollow, interlocking region of the female plate. The screw holes  102  may be of a standard configuration, a locking configuration or a variable angled, locking configuration. The overall length of the rod  100  will be variable  104  so as to better match the anatomical dimensions of a given patient. The distal end  109  of the rod  100  has multiple screw holes  105  to allow for mechanical connection to the bony structures of the pelvic rim. Multiple screw holes  105  are positioned at the distal rod end  109  may be of a standard configuration, a locking configuration or a variable angled, locking configuration. A circular recess  106  is positioned at the distal rod end  109  to allow for engagement of a Schanz pin connector for application of mechanical leverage during manipulation of the pelvic fracture. 
       FIG. 2  illustrates the male plate components of the Less Invasive, Multi-Holed, Variable Positioned Locked Pelvic Stabilization System. The medial end  208  of the rod  200  contains multiple holes  201  to allow screws to pass through the rod  200 , thus anchoring it to the female plate and to the underlying bony structures. As with the female rod  100 , the rod length is variable  202  to match a wide range of patient sizes. Identical to the female rod, screw holes  203  and Schanz pin connectors  204  are located at the distal rod end  209 . 
       FIGS. 3A-3B  illustrate the fully joined positions of the male  200  and female  100  rods, which comprise connecting means for rigidly connecting the medial ends of the male and female plate components. When the two components are linked they form a stable arch  300  that spans the ventral aspect of the patient&#39;s pelvis. Linkage of this stable construct to the fractured pelvis controls both halves of the pelvis and therefore stabilizes the fracture. 
       FIG. 4  illustrates a close-up view of the medial ends  108 ,  208  of both the female  100  and male  200  rod components as they would approach each other prior to interlocking. Both the male  200  and female  100  rods have a series of matching screw holes  105 ,  203  along their distal ends. 
       FIG. 5  illustrates an expanded view of the female  100  and male  200  rod components fully interlocked. Two bone screws  501  are shown traveling through aligned screw holes  201 ,  102  in both the male  200  and female  100  rod components. The bone screws  501  path through the linked hardware and into the underlying pelvic bone. 
       FIG. 6  illustrates an expanded view of the female  100  and male  200  rod components slightly retracted from a fully interlocked position. Bone screws  501  are inserted through the pair of interconnected rods  100 ,  200  in the same positions as the fully interconnected rod configuration. Alternative screw positions are available as warranted by the position of dense bone for reception for the protruding bone screw  501 . 
       FIG. 7  illustrates an expanded view of the female  100  and male  200  rod components in a position that is approximately one-half interlocked. Two full length screws  501  are utilized to attach the pelvic LISS hardware to the underlying pelvic bone while a third non-penetrating, inter-rod screw  601  is placed centrally to aid in the mechanical interlocking of the male  200  and female  100  rods. 
       FIG. 8  illustrates an expanded view of the female  100  and male  200  rod components in a configuration of minimal interlocking. The female  100  and male  200  rod components are mechanically joined via two bone screws  501  and one inter-rod screw  601 . 
       FIGS. 9A-9F  illustrate the female component  900  of the Spring Ratcheting Less Invasive Pelvic Stabilization System. Unique features of the female component  900  of the Spring Ratcheting Less Invasive Pelvic Stabilization System include a series of slots  901  through the sidewall of the rod  900  that are positioned at the male entry end  902  of the component. The function of these slots  901  is to allow mechanical retention of tabbed leaf springs  1001  embedded along the received male component  1000  (see  FIGS. 10A-10B ). Also present at the receiving end  902  of the rod  900  are two dorsal and pectoral flanges  903  containing locking screw holes  904 . Locking screws are inserted through these holes  904  to help mechanically secure the pelvic LISS to the patient&#39;s pubic symphysis bone. As with the alternative embodiments of the pelvic LISS, the distal, non-receiving end  905  of the female component  900  consists of multiple locking screw holes  906  and a Schanz pin engagement port  907 . 
       FIGS. 10A-10F  illustrate the male component  1000  of the Spring Ratcheting Less Invasive Pelvic Stabilization System. Unique features of the male component  1000  of the Spring Ratcheting Less Invasive Pelvic Stabilization System include a series of tabbed leaf springs  1001  embedded along the surface of the lateral portion of the component. Upon insertion into the female component  900 , the tabbed leaf springs  1001  are compressed. With further insertion, the tabbed leaf springs  1001  engage with the slots  901  along the female component  900 . Successive insertion is possible to facilitate further fracture reduction while disengagement will be mechanically impeded due to the interlocking of the leaf spring/slot combination. The slots  901  and tabbed leaf springs  1001  comprise connecting means for rigidly connecting the male and female components together. As with the alternative embodiments of the pelvic LISS, the distal end of the male component consists of multiple locking screw holes  1004  and a Schanz pin engagement port  1005 . 
       FIGS. 11A-11C  illustrate the novel tools for disengaging the male and female components of the Ratcheting Less Invasive Pelvic Stabilization System. Disengagement would be clinically needed during hardware removal after bone healing has generated sufficient mechanical stability. The custom clamp device  1001  would be surgically inserted to encase the medial/linked ends of the male  1000  and female  900  plates. The insets provided along the clamp surface  1102  are designed to be of a depth sufficient to release the leaf springs  1001  of the male plate  1000  from the slots  901  of the female plate  900 . Once the leaf springs  1001  are freed, the male and female plates  1000 ,  900  are free to disengage and for hardware removal to proceed. 
       FIGS. 12A-12D  illustrates the Cable Driven Less Invasive Pelvic Stabilization System. The Pelvic Cable LISS could be utilized clinically as follows.
         1. LISS plates are inserted subcutaneous or submuscular. Plates are anchored via screws at the iliac crest and also possibly at the pubic symphysis. One of the two plates  1201  has a hollow tunnel with a cable  1202  running along its length. The cable  1202  has an attachment feature at its end  1203  to securely capture the end  1204  of the opposing plate  1205 . The attachment feature may be a locking feature such as coarse threading or a rotational interlock.   2. Once plates are secured to each hemi-pelvis in proper anatomic relation, the surgeon manipulates the cable from the end of one plate and secures it to the end of the other plate. Standard surgical instruments would be used to facilitate this maneuver.   3. Once the plates  1201 ,  1205  are linked through the cable  1202 , the cable  1202  is tensioned at its exit point at the lateral plate end.   4. The force provided by the cable tension should close any misalignment between the pelvic halves.   5. Once the fractured pelvis is brought back into anatomic alignment, plates can be linked or additional screws placed. Whether the tensioned cable is removed once the anatomy is believed stable or the cable is left inside the construct under some degree of tension is optional.       

       FIGS. 13A-13F  illustrate the female component  1300  of the Thread and Screw Driven Pelvic LISS. The female rod component  1300  exhibits locking screw holes  1301  well as Shanz pins connectors  1302  along its proximal end. The medial end of the female rod component exhibits a threaded inner surface  1303  for joining with the screw component of the male device and lateral flanges  1304  with a series of locking screw holes  1305 . 
       FIGS. 14A-14B  illustrate the male component  1400  of the Thread and Screw Driven Pelvic LISS. The male rod component  1400  contains a flexible cable  1401  that runs along the interior length of the rod  1400 . The medial end of the cable is attached to a rotating screw  1402  that is size and shape matched to engage with the female threaded medial portion  1303  of the associated female rod component  1300  ( FIGS. 13A-13B ). The proximal end  1403  of the cable  1401  is fitted with a mechanical means for coupling with an external, rotating drive mechanism (not shown) such as threading or a mechanical interlocking configuration. The proximal end of the male rod  1400  may be capped with a threaded end cap  1404  to limit access to bodily fluids once proper clinical fixation is obtained. Proximal attachment of the device to the patient&#39;s pelvic bone may be accomplished via insertion of bone screw through locking screw holes  1405  positioned along a lateral flange  1406 . Interoperative torque may be applied to the construct as an aid in obtaining proper alignment through a Shanz pin port  1407  located toward the proximal end of the male rod component  1400 . The flexible cable  1401  comprises connecting means for rigidly connecting the male and female components together. 
       FIG. 15  illustrates a Clamp Adjusted Pelvic Stabilization System as it would be positioned on the pelvis. On both the right and left sides of the pelvis, rods  1501  arc around the pelvis from the iliac crest  1502  to the pubic symphysis  1503 . Proximal rod ends  1504  are secured to the pelvic bone via bone screws inserted through multiple, threaded screw holes  1505 . Medial rod ends  1506  are secured to each other via a mechanical linkage that comprises a screw-driven, clamping device  1507 ,  1508  that simultaneously holds rigid left and right rods at the medial position of their overlapping. The screw-driven, clamping device  1507 ,  1508  comprises connecting means for rigidly connecting the medial rod ends  1506  together. Rigid fixation of the rod ends  1506  to the underlying pelvic bone is accomplished via individual right and left clamps  1509  and screws  1510  that confine said rods and rigidly hold them to the underlying pelvic bone via bone screw placement. 
       FIG. 16A  illustrates a Clamp/Plate Pelvic Stabilization System as it could be positioned on the pelvis. On both the right and left sides of the pelvis, rods  1601  arc around the pelvis from the iliac crest  1602  to the pubic symphysis  1603 . Proximal rod ends are secured to the pelvic bone via bone screws inserted through multiple, threaded screw holes  1620 . Across the pubic symphysis  1603 , a rigid baseplate  1605  is positioned and secured through placement of multiple bone screws  1606 . Dual channels along the outer surface of the plate  1605  accept the medial ends of the right and left rods  1601 . A clamping plate  1608  compresses the rods  1601  into the baseplate  1605  via insertion of multiple locking screws  1609 . The rigid baseplate  1605  and clamping plate  1608  together comprise connecting means for rigidly connecting the medial ends of the right and left rods  1601  together. 
       FIG. 16B  illustrates an expanded view of the medial segment of an alternative format for the Clamp/Plate Pelvic Stabilization System. A plate  1607  is surgically positioned over the pelvic pubis and rigidly anchored through insertion of multiple locking bone screws  1604 . The medial ends of the right and left hemipelvic rods  1601  are rigidly bound together via compressive forces applied through placement of a capping plate  1608  and insertion and tightening of screws  1609  that travel through the capping plate  1608  and engage with threaded screw holes  1610  within the larger plate  1607  positioned beneath. The plate  1607  and capping plate  1608  together comprise connecting means for rigidly connecting the medial ends of the right and left hemipelvic rods  1601  together.