Abstract:
A protective system for facilitating revision surgery includes a protective pad with a base portion and an overlying portion spaced apart from the base. A fluid pocket is formed between the base portion; and the overlying portion. The protective system prevents formation of adhesions or scar tissue in the area occupied by the protective pad. Thus a clean plane is obtained during revision surgery on the patient through an incision in the fluid pocket.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to surgical devices and, more particularly, to devices used to facilitate revision surgery implicating vulnerable anatomical parts. 
       BACKGROUND 
       [0002]    Spinal disorders requiring surgical procedures are well known. The lumbar region of the human anatomy, for example, is a frequent site of spinal disorders which may be corrected by surgical procedures carried out anteriorly of the lumbar vertebrae including, for example, surgical procedures involving disc removal and/or replacement. 
         [0003]    In anterior spinal surgical procedures, the initial surgery is through an unscarred and substantially clear path to the surgical site. In revision surgery, however, the path to the surgical site has typically degraded as a result of the previous surgery resulting in scarring and other developments which may interfere with the revision surgery. 
         [0004]    Moreover, the present technology in spinal surgeries is typically focused on anterior insertion of intervertebral prostheses, and other anterior surgical procedures. Consequently, the potential of anterior dislocation of prostheses and vertebral structures as well as potential injury to the significant blood vessels located in proximity to the spine is increased. 
         [0005]    U.S. Pat. No. 6,475,219 issued to Alexis P. Shelekov on Nov. 5, 2002, addressed the aforementioned conditions. The &#39;219 patent, the teachings of which are herein incorporated by reference, discloses a method and device for protecting major vessels and other anatomical parts from complications as a consequence of anterior spinal surgical procedures. In particular, the &#39;219 patent discloses a method for protecting major blood vessels, such as the aorta and the vena cava, and providing some protection against anterior dislocation of vertebral bodies adjacent these vessels. The &#39;219 patent also provides for minimizing the formation of adhesions or unwanted joining of certain tissues and body structures to each other pursuant to anterior spinal surgery. 
         [0006]    The &#39;219 patent provides a significant improvement in protection of vulnerable anatomical parts in areas subject to revision surgery. Nonetheless, a need exists for a device which further simplifies revision surgeries, particularly in the area of vulnerable body parts. It would be advantageous if the device facilitated location of the targeted surgical area. Moreover, it would be beneficial if the device could be conveniently interposed between the spinal column and anatomical parts, particularly, major blood vessels such as the aorta and the vena cava, so that the anatomical parts are protected during a surgical procedure and/or are not subject to the development of adhesions or tissue which may produce complications during revision surgery. 
       SUMMARY 
       [0007]    A protective system and method is disclosed. In accordance with one method according to the invention, a patient is prepared for a first surgical procedure. A first incision is made through the skin of the patient in accordance with the first surgical procedure and a target area for the first surgical procedure is exposed through the first incision. A step of the first surgical procedure is then performed on the target area for the first surgical procedure. Thereafter, a protective pad with a fluid pocket is placed between a vulnerable anatomical part and the target area for the first surgical procedure and the first incision is closed in accordance with the first surgical procedure with the protective pad between the vulnerable anatomical part and the target area. 
         [0008]    In one embodiment, a protective system for facilitating revision surgery includes a protective pad with a base portion of biocompatible material and an overlying portion of biocompatible material spaced apart from the base, the base portion and the overlying portion forming at least a portion of a fluid pocket. The system further includes at least one bone anchor for affixing the protective pad to a bone. 
         [0009]    The above-described features and advantages, as well as others, will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  shows a perspective view of a protective pad with a telltale made in accordance with principles of the present invention; 
           [0011]      FIG. 2  shows a cross-sectional view of the protective pad of  FIG. 1  taken along the line A-A of  FIG. 1 ; 
           [0012]      FIG. 3  shows a side perspective view of a spinal column upon which the protective pad of  FIG. 1  may be placed in accordance with principles of the present invention; 
           [0013]      FIG. 4  shows a partial perspective anterior view of a prevertebral space including anatomical parts which may be encountered during a surgical procedure in accordance with principles of the present invention; 
           [0014]      FIG. 5  shows a partial schematic view of a portion of the prevertebral space of  FIG. 4  superimposed upon a portion of the spinal column of  FIG. 3  to illustrate the location of some of the anatomical parts of  FIG. 4  relative to the spinal column; 
           [0015]      FIG. 6  shows a partial anterior perspective view of a protective pad attached to the spinal column of  FIG. 3  underneath the aorta and the vena cava of a patient; 
           [0016]      FIG. 7  shows a cross-sectional view of the protective pad of  FIG. 6  taken along the line B-B of  FIG. 6  wherein the fluid pocket of the protective pad is located between the spinal column and the aorta and the vena cava of the patient; 
           [0017]      FIG. 8  shows a partial anterior perspective view of the protective pad of  FIG. 6  with incisions made therein to form a leaf; 
           [0018]      FIG. 9  shows a partial anterior perspective view of the protective pad of  FIG. 6  with the leaf retracted so as to retract the aorta and the vena cava of the patient and to expose a portion of the base of the protective pad; 
           [0019]      FIG. 10  shows a perspective view of an alternative protective pad with a telltale made in accordance with principles of the present invention that separates vulnerable anatomical parts from a target area of a spine and further extends between the vulnerable anatomical parts to facilitate access to a target area through the space between the anatomical parts; 
           [0020]      FIG. 11  shows a cross-sectional view of the protective pad of  FIG. 10  taken along the line C-C of  FIG. 10  showing concave trailing portions extending away from the front end of the protective pad; 
           [0021]      FIG. 12  shows a top plan view of the protective pad of  FIG. 10 ; 
           [0022]      FIG. 13  shows a cross-sectional view of the protective pad of  FIG. 10  taken along the line C-C of  FIG. 10  in position between the common ileac arteries and veins of the patient; 
           [0023]      FIG. 14  shows a partial anterior perspective view of the protective pad of  FIG. 10  located on a patient with incisions made in the overlying portion of the protective pad to form a leaf; 
           [0024]      FIG. 15  shows a partial anterior perspective view of the protective pad of  FIG. 14  with one leaf retracted so as to retract one common ileac vein and one common ileac artery of the patient and to expose a portion of the base of the protective pad; and 
           [0025]      FIG. 16  shows a partial anterior perspective view of the protective pad of  FIG. 14  with two leafs retracted so as to retract both common ileac veins and both common ileac arteries of the patient and to expose two portions of the base of the protective pad. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]      FIG. 1  depicts a protective pad  100 . The protective pad  100  has a generally rectangular shape with four fastener areas  102 ,  104 ,  106  and  108  located at each of the four corners of a base  110  of the protective pad  100 . In this embodiment, the fastener areas  102 ,  104 ,  106  and  108  include bone fastener holes  112 ,  114 ,  116  and  118 . The bone fastener holes  112 ,  114 ,  116  and  118  may be used with a bone fastener such as a screw, peg or nail to attach the protective pad  100  to a bone. Alternatively, the protective pad  100  may be sutured in place. 
         [0027]    As shown in  FIG. 2 , an overlying portion  120  extends above a portion of the base  110 . The overlying portion  120  and the base  110  define a fluid pocket  122 . In the embodiment of  FIG. 2 , the overlying portion  120  and the base  110  are configured to provide an impermeable barrier about the fluid pocket  122 . Accordingly, fluid within the fluid pocket  122  is not allowed to exit the fluid pocket  122 . Additionally, fluids outside of the protective pad  100  are not allowed to enter the fluid pocket  122 . The protective pad  100  further includes a telltale  124  which in this embodiment extends from the base  110 . The telltale  124  includes a marker  126 . 
         [0028]    The overlying portion  120 , the base  110  and the telltale  124  are formed from a flexible biocompatible material or subdermal implant material, such as Silastic brand silicone rubber or similar organosiloxane polymers. The fluid pocket  122  is filled with a biocompatible fluid which may be liquid or gaseous. In one embodiment, carbon dioxide gas is used. Other biologically inert gasses may be used in alternative embodiments. The fluid pocket  122  may be configured to provide a thin layer of fluid between the overlying portion  120  and the base  110  or to provide a more substantial separation between the overlying portion  120  and the base  110  as shown in  FIG. 2 . The marker  126  in the embodiment of  FIG. 1  includes a radiodense material so as to be readily identified using radiography. 
         [0029]    The present invention is particularly well suited for use in surgeries on the spinal column of a patient. Referring to  FIG. 3 , a spinal column  128  of a human being is illustrated. In the drawing figures, certain anatomical details may be omitted or shown somewhat schematically in the interest of clarity. The spinal column  128  includes a cervical region  130 , a dorsal region  132 , a lumbar region  134  and a pelvic region  136 . 
         [0030]    Two of the regions of the spinal column  128  that are most commonly operated on are the lumbar region  134  and the pelvic region  136 . In these regions, the area including lumbar L4  138  and lumbar L5  140  and the area including lumbar L5  140  and the sacrum  142  are the areas to which most spinal operations are directed. 
         [0031]    One surgical approach that is used when performing a surgical procedure on the above described areas is identified as the Pararectal Retroperitoneal Approach. In this approach, which may be used for procedures such as a disc removal or disc prosthesis installation, the skin of the patient is incised in a curved line over the lateral border of the rectus muscle of the patient. Through this incision, the prevertebral space of the patient is exposed. 
         [0032]      FIG. 4  depicts various anatomical parts that are located within or adjacent to a prevertebral space  144 . As depicted therein, the vena cava  146  extends generally along a line directly above the spinal column (not shown in  FIG. 4 ). The vena cava  146  receives blood from the common iliac veins  148  and  150  and their respective branches. The abdominal aorta  152  begins to the right of the vena cava  146  as viewed in  FIG. 4  and extends over the top of the vena cava  146  lower down in the prevertebral space  144 . The abdominal aorta  152  provides blood to two common iliac arteries  154  and  156  and their respective branches. 
         [0033]    The vena cava  146 , the common iliac veins  148  and  150  and their respective branches, the abdominal aorta  152 , and the common iliac arteries  154  and  156  and their respective branches are anterior to, and generally co-linear with, the spinal column  128  as shown in  FIG. 5 . Accordingly, when using the Pararectal Retroperitoneal Approach, at least some of these blood vessels must be moved to the side to expose the targeted area of the spinal column  128 . During an index surgical procedure, movement of the blood vessels is accomplished by retracting the vena cava  146  and the abdominal aorta  152  to one side to expose the lumbar L4  138  and lumbar L5  140  vertebrae or by spreading the common iliac vein  148  and the common iliac artery  154  apart from the common iliac vein  150  and the common iliac artery  156  to expose the area about the lumbar L5  140  and the sacrum  142 . Depending on the actual location of the veins and arteries of a particular patient and the area being targeted, branches of the iliac vessels may need to be moved in addition to or in place of the iliac vessels. 
         [0034]    The blood vessels and surrounding tissue exhibit sufficient flexibility and looseness for the amount of retraction required to access areas using the Pararectal Retroperitoneal Approach during an initial surgery on a target area. After the initial surgery, however, scar tissue and/or adhesions may form about the surgical path and restrict the flexibility and looseness of the anatomical parts around the path to and in the area of the target area. To facilitate a revision surgery in the same area as the index surgery, a protective pad may be used to reduce complications resulting from scar tissue and/or adhesions. Preferably, the protective pad is attached to the spinal column  128  during the initial surgical operation. More preferably, the protective pad is attached after a procedure has been conducted on a target area and before the blood vessels or other anatomical parts are released from a retracted position. 
         [0035]      FIG. 6  depicts a portion of the prevertebral space  144  after the blood vessels have been released from retraction. The protective pad  158  is attached to the lumbar L4  138  vertebra with two fasteners  160  and  162  which are inserted through the fastener areas  164  and  166 , respectively. Preferably, holes are provided in the fastener areas  164  and  166  which allow the shafts (not shown) of the bone fasteners  160  and  162 , which in this embodiment are screws, to pass through the protective pad  158 . Similarly, the protective pad  158  is attached to the lumbar L5  140  vertebra with two fasteners  168  and  170  which are inserted through the fastener areas  172  and  174 , respectively. 
         [0036]    In this configuration, the base  176  of the protective pad  158  is located adjacent to the spinal column  128  and an overlying portion  178  and a fluid pocket  180  are located beneath the vena cava  146  and the abdominal aorta  152  of the patient as shown in  FIG. 7 . In a preferred embodiment, the protective pad  158  is selected from a kit of protective pads having different sizes. This allows a pad to be selected with a length that extends, in this example, from about the mid-point of the lumbar L4  138  vertebra to about the mid-point of the lumbar L5  140  vertebra. Additionally, the width of the protective pad  158  is selected to ensure the fluid pocket  180  extends outwardly from the vena cava  146  and the abdominal aorta  152  on at least one side as is discussed more fully below. In this embodiment,  FIG. 7  shows that the fluid pocket  180  extends outwardly from both the vena cava  146  and the abdominal aorta  152  in a medial-lateral direction. The overall width of the protective pad  158  is preferably selected to provide complete coverage of the targeted vertebrae from psoas to psoas. 
         [0037]    The telltale  182  extends away from the protective pad  158  and includes a marker  184  which may be similar to the marker  126  of  FIG. 1 . To aid in rapidly locating the telltale  182  during a revision surgery, the end portion with the marker  184  may conveniently be tacked to the rectus of the patient or affixed to another readily identifiable location by some other means. 
         [0038]    Accordingly, during a revision surgery on or near the targeted area of the first procedure, radiography is used to identify the location of the marker  184  on the telltale  182 . Then, after preparing the incision area in accordance with a proper surgical protocol, an incision in the skin of the patient is made and the telltale  182  is located based upon the radiography. In this embodiment, the telltale  182  is shown attached to the base  176 . Alternatively, the telltale  182  may be attached to the overlying portion  178 . In the event the telltale  182  does not interfere with the remaining steps of the surgical procedure, the telltale  182  may remain attached to the patient. Alternatively, if the telltale  182  is attached to the overlying portion  178  or will interfere with ensuing steps, the telltale  182  is detached from the patient. 
         [0039]    In either event, the surgeon then follows the telltale  182  to the protective pad  158 . After lysis of adhesions on the portion of the pad  158  on the side opposite the direction of desired retraction, a longitudinal incision  186  is made through the overlying portion  178  along a line adjacent to the vena cava  146  or the abdominal aorta  152  as shown in  FIG. 8 . The width of the fluid pocket  180  preferably extends outwardly of both the vena cava  146  and the abdominal aorta  152 . This allows a surgeon to select the direction in which the blood vessels will be retracted based upon the particular condition of the patient. If the fluid pocket only extends outwardly of one of the two blood vessels, then the incision is preferably made to allow retraction of the blood vessels in a direction opposite the direction in which the fluid pocket extends outwardly of the one of the two blood vessels. 
         [0040]    The overlying portion  178  may then be manipulated to retract the adjacent blood vessel away from the longitudinal incision  186  allowing a transverse incision  188  to be made in the overlying portion  178  at one end of the protective pad  158  and another transverse incision  190  along the opposite end of the protective pad  158 . The longitudinal incision  186  and the transverse incisions  188  and  190  form a leaf  192 . 
         [0041]    Once the leaf  192  is sufficiently formed, a retractor is placed through the longitudinal incision  186  and into the fluid pocket  180 . The retractor is used to move the leaf  192  in a direction away from the longitudinal incision  186 . If needed, any of the incisions may be further extended during retraction. As shown in  FIG. 9 , the leaf  192 , acting as a protective layer, is used to retract the vena cava  146  and the abdominal aorta  152  to reveal an exposed portion  194  of the base  176 . An incision may then be made through the exposed portion  194  to reveal the targeted area. 
         [0042]    As stated above, when using the Pararectal Retroperitoneal Approach in the area about the lumbar L5  140  and the sacrum  142 , the common iliac vein  148  and the common iliac artery  154  are spread apart from the common iliac vein  150  and the common iliac artery  156 . Accordingly, it is desirable to form two different leaves from the protective pad, one leaf for each set of blood vessels. The protective pad  158  may be used in this setting with appropriate modification of the location of the longitudinal cut to a central area and using transverse cuts to from two leaves. An alternative protective pad that may be used is the protective pad  200  shown in  FIG. 10 . 
         [0043]    The protective pad  200  has a generally rectangular base  202  with four fastener holes  204 ,  206   208  and  210  located at each of the four corners. An overlying portion  212  is attached to the base  202  so as to define a fluid pocket  214  (see  FIG. 11 ). The overlying portion  212  may be attached to the base  202  by use of an adherent or other acceptable method such as ultrasonic welding. The fluid pocket  214  is generally plough shaped with a narrow end portion  216 . Two trailing portions  218  and  220  extend away from the end portion  224  and diverge from each other. The trailing portions  218  and  220  join a wide end portion  222  so as to form a generally triangular shape when viewed from above the fluid pocket  214  (see  FIG. 12 ). The protective pad  200  further includes a telltale  224  which in this embodiment extends from the narrow end portion  216 . The telltale  224  includes a marker  226 . 
         [0044]    The protective pad  200  is implanted on a bone such as the spinal column  128  following essentially the same steps set forth above with respect to the protective pad  158 . The procedure for performing a revision surgery in the vicinity of the implanted protective pad  200  is the same as the method set forth above with respect to protective pad  158  until the telltale  224  is followed to the protective pad  200 . 
         [0045]    The protective pad  200  is configured such that when it is implanted in the area of the lumbar L5  140  and the sacrum  142 , the common iliac vein  148  and the common iliac artery  154  are spaced apart from the common iliac vein  150  and the common iliac artery  156  by the plough shaped fluid pocket  214  as shown in  FIG. 13 . The protective pad  200  is further configured such that the overlying portion  212  extends away from the spinal column  128  to about the same height as the aorta is located above the spinal column  128 . Accordingly, when the telltale  224  is tracked to the protective pad  200 , at least some of the overlying portion  212  will be exposed between the iliac vein  148  and the common iliac artery  154  on one side and the common iliac vein  150  and the common iliac artery  156  on the other side as shown in  FIG. 14 . 
         [0046]    The area about the protective pad  200  is then prepared for retraction of the blood vessels. In a preferred approach, a longitudinal incision  228  is made through the overlying portion  212  along a line between the narrow end portion  216  and the wide end portion  222 . Typically, the longitudinal incision  228  will be made approximately along the centerline of the overlying portion  212 . Depending on the conditions for a particular patient, the location of the incision may be adjusted to one side or the other. Transverse incisions  230  and  232  are made along the wide end portion  222 . Of course, the order of the incisions may be modified. The longitudinal incision  228  and the transverse incisions  230  and  232  form leafs  234  and  236 . 
         [0047]    Once a leaf is sufficiently formed, a retractor (not shown) is placed through the longitudinal incision  228  and into the fluid pocket  214 . The retractor is used to move one of the leafs  234  or  236  in a direction away from the longitudinal incision  228 . As shown in  FIG. 15 , the leaf  234  is positioned against the common iliac vein  148  and the common iliac artery  154  and their branches. The leaf  234  thus provides protection to the common iliac vein  148 , the common iliac artery  154  and their respective branches. The leaf  234  may further be used to retract the common iliac vein  148  and the common iliac artery  154  and their branches to reveal exposed portion  238  of the base  202 . 
         [0048]    If desired, a second retractor (not shown) may be used to move the other of the leafs  234  or  236  in a direction opposite of the direction of the first retraction. Thus, as shown in  FIG. 16 , the leaf  236  is positioned against the common iliac vein  150  and the common iliac artery  156  and their branches. The leaf  236  thus provides protection to the common iliac vein  150 , the common iliac artery  156  and their respective branches. The leaf  234  may further be used to retract the common iliac vein  150  and the common iliac artery  156  and their branches to reveal portion  240  of the base  202 . An incision may then be made through the base  202  using one or both of the exposed areas  238  and  240  to reveal the targeted area. 
         [0049]    While the present invention has been illustrated by the description of exemplary processes and system components, and while the various processes and components have been described in considerable detail, applicant does not intend to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will also readily appear to those ordinarily skilled in the art. The invention in its broadest aspects is therefore not limited to the specific details, implementations, or illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.