Abstract:
A surgical retractor capable of lifting and spreading a surgical opening while minimizing trauma to the patient in a self-contained apparatus. The surgical retractor has a curved rack and two arms. Either or both of the arms is adjustable in position along the rack, and/or configured to traverse the rack, and each arm has a retraction blade. At least one of the retraction blades is configured to securely engage skeletal structure. The retractor rack may also have both a curved portion and a linear portion, with either or both arm adjustable along the curved or linear portion of the rack, or configured to traverse the curved or linear portion of the rack. An accessory arm, articulable with respect to the retractor, may also be provided.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of Invention  
           [0002]    The invention relates to the field of medical instruments, and more particularly, to a curved rack retractor for use in less invasive thoracic surgical procedures.  
           [0003]    2. Description of Related Art  
           [0004]    Minimally invasive surgical procedures have been developed in recent years to reduce the trauma caused to the patient during surgery. Particularly in cardiac or other thoracic surgeries, the median sternotomy is quite invasive, resulting in increased incidence and/or severity of patient pain and discomfort, complications of surgery, including mortality, and extended recovery periods. One alternative is a thoracotomy procedure.  
           [0005]    Thoracotomy procedures use smaller incisions, reducing trauma to the patient. However, in thoracotomy procedures, the surgery is more difficult because of decreased access and visualization of the surgical site. Access is typically provided through an intercostal space that is increased by spreading the ribs with a retractor. Improved access can be obtained with minimal additional trauma to the patient by lifting one of the ribs, typically the superior rib, as it is retracted. Certain apparatus have been devised to perform this lifting and retracting function.  
           [0006]    One example is disclosed in U.S. Pat. No. 6,159,231 to Looney, et al. However, the Looney retractor requires an external lifting device to provide lift. A retractor capable of providing lift by its own design is preferable. Another example is disclosed in U.S. Pat. No. 6,416,468 to Deckman, et al. Deckman shows a retractor that lifts without outside apparatus by applying a countering downward force to a footplate on the patient&#39;s body. This could also be improved because the downward force of the footplate can cause additional trauma.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    Therefore, it is the object of the present invention to provide a surgical retractor capable of lifting and spreading the ribs of the patient in a self-contained apparatus. It is another object of the present invention to provide a surgical retractor capable of lifting and spreading the ribs of the patient while minimizing additional trauma.  
           [0008]    To achieve these and other objects, provided is a surgical retractor comprising a curved rack and a plurality of arms securable to the rack, typically two. At least one of the arms is adjustable in position along the rack, or configured to traverse the rack, and at least two of the arms each have a retraction blade. At least one of the retraction blades is configured to securely engage skeletal structure.  
           [0009]    The retractor rack may also have both a curved portion and a linear portion. Moreover, one or more arms may be adjustable in position along the curved or linear portion of the rack, or be configured to traverse the curved or linear portion of the rack. An accessory arm, articulable with respect to the retractor, may also be provided. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    These and other features, advantages and benefits will be made apparent through the following descriptions and accompanying figures, where like reference numerals refer to the same features across the various drawings.  
         [0011]    [0011]FIG. 1 shows a perspective view of a curved rack retractor according to a first embodiment of the present invention;  
         [0012]    [0012]FIG. 2 shows a cross sectional view of the first embodiment in a closed position;  
         [0013]    [0013]FIG. 3 shows a cross sectional view of the first embodiment in an open position;  
         [0014]    [0014]FIG. 4 shows a perspective view a curved rack retractor according to an alternate embodiment;  
         [0015]    [0015]FIG. 5 shows a profile view of a combination linear and curved rack according to another alternate embodiment of the present invention; and  
         [0016]    [0016]FIG. 6 shows a perspective view of a combination linear and curved rack retractor according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    In its preferred embodiments, the present invention is designed for use in less-invasive thoracotomy procedures. With reference to FIG. 1, a first embodiment of the present invention, a surgical retractor, generally  10 , has a curved rack  12 . FIG. 1 illustrates the rack having a smooth curvature of uniform radius, however the radius of curvature may also vary along the length of the rack. Attached to the rack  12  are a first arm  14  and a second arm  16 . The first arm  14  and second arm  16  are provided with inferior and superior retraction blades,  18  and  20 , respectively. Second arm  16  is shown to be adjustable in position along the rack  12 , with means to traverse the length of the rack  12 .  
         [0018]    With reference to FIG. 2, a cross section of the retractor  10  in a closed position is shown in use. To use the retractor  10  in a thoracic surgery, the first arm  14  and second arm  16  are brought within proximity of each other. The inferior retraction blade  18  and superior retraction blade  20  are inserted through a surgically formed intercostal space  22 , and brought to engage the inferior and superior ribs, respectively.  
         [0019]    The inferior retraction blade  18  is configured to anchor the retractor  10  to the inferior rib to prevent rotation around an axis transverse to the rack  12  as the arms are spread. This may be accomplished a number of ways, for example, the inferior retraction blade  18  may be sized to compress the musculoskeletal tissue of the thoracic wall for a secure fit. Alternately or additionally, the inferior retraction blade  18  may include a deformable insert  19 , for example made of a cellular foam material, to conform to the shape of the inferior tissue while providing a secure connection. The insert would further reduce the trauma at the attachment point, and/or improve the stability of the attachment. Alternately, an inferior blade  18  may engage the inferior rib, or other skeletal structure, without engaging other tissue. It will be seen in FIG. 2 that inferior retraction blade  18  engages both a skeletal structure, the inferior rib, and the musculoskeletal tissue.  
         [0020]    Referring now to FIG. 3, the retractor  10  is shown with the first arm  14  and second arm  16  spread in an open position. The second arm  16  has been moved along the rack  12 . The surgically formed intercostal space  22  has been increased to allow surgical access to the thoracic cavity  24  below. By virtue of the curved rack  12 , and the engagement of the inferior retraction blade  18  with the inferior rib, the superior rib is lifted as it is spread from the inferior rib, thereby improving access and visualization to the surgical site. This is accomplished without the need for external apparatus to perform the lifting function, or downward pressure on another location of the patient&#39;s body.  
         [0021]    With reference to FIG. 4, a further embodiment of the retractor  10  is shown. In this embodiment, the retractor  10  includes an accessory arm  26 . Any of a number of surgical accessories for use during the thoracic procedure may conveniently be secured to the accessory arm  26 . One surgical accessory contemplated is an ILLUMINATED VACUUM ASSISTED HEART SURGERY RETRACTOR, which is the subject of co-pending U.S. patent application filed Dec. 19, 2002 by the present inventors, Ser. No. [unassigned] (Attorney Docket No. 16034), hereby incorporated by reference for all purposes. The accessory (not shown) can be secured to the end of the accessory arm  26  at a mounting slot  34 , provided for that purpose, by means of a clamp provided on the accessory in a manner known in the art. The accessory arm can include an articulating slot  28  by which it is attached to the rack  12 , and through which it may be articulated relative to the retractor  10  to locate any attached surgical accessories.  
         [0022]    In use, an accessory will be secured to the accessory arm  26  at mounting slot  30  and located in a desired position by articulation around articulating slot  28 . Thereafter, the surgeon secures the accessory arm  26  in the desired position. As illustrated, a thumbscrew  36  is provided to secure the accessory arm  26 .  
         [0023]    As shown and described in the embodiments of FIGS.  1 - 4 , the first arm  14  has-been fixed to the rack  12 . This is most effective when the rack  12  has only a curved portion of constant radius. However, either or both of the first and second arms  14 ,  16 , may be made to adjust in position with respect to the rack  12 . In its simplest form, adjusting the position of the arms  14 ,  16 , along the rack  12  includes multiple positions at which the arms may be attached to the rack. After engaging the retraction blades with the respective ribs, the surgeon may manually retract the superior rib, and attach the second arm  16  to the rack  12  at a desired position. More preferably, either or both of first and second arms  14 ,  16  include means to traverse the length of the rack  12  while attached thereto.  
         [0024]    The means to traverse the rack  12  will now be described with respect to the embodiment in which only one arm is adjustable relative to the rack  12 . It will be apparent to those skilled in the art that the traversing means described is equally suitable for use on both arms.  
         [0025]    One means to traverse includes a rack-and-pinion arrangement. Rack  12  is provided with a toothed area  30  along some or all of its length, but especially over the desired range of motion of the second arm  16 . The second arm  16  is also provided with a toothed pinion (not shown) mounted on one end of a pinion shaft (also not shown) and positioned to mesh with the toothed area  30 . At the opposite end of the pinion shaft is a key  32  to rotate the pinion shaft and pinion, and thereby adjust the position of the second arm  16 .  
         [0026]    Additionally, the means to traverse can be provided with means to prevent the unwanted movement of the arm. This can include a ratchet mechanism to prevent rotation of the pinion, or other means as known in the art. Additionally, if a ratchet mechanism is used, a release means may be provided allow free rotation of the pinion, thereby allowing the second arm  16  to move freely along the rack  12 .  
         [0027]    Other means for adjusting the position of the arms will be apparent to those skilled in the art without departing from the scope of the present invention. Those would include a friction roller in place of the pinion, with a suitable high friction engaging surface in the position of the toothed rack. The friction roller system may also include a ratchet mechanism, and/or a release. Alternately, a cable drive arrangement may be provided to allow the first and second arms  14 ,  16 , to traverse the rack  12 . One cable drive arrangement known in the art is disclosed by U.S. Pat. No. 5,944,736 to Taylor, et al., hereby incorporated by reference for all purposes. The cable drive, as illustrated at FIG. 35, includes its own means to prevent the unwanted motion of the arms.  
         [0028]    With reference to FIG. 5, shown is a profile view of a rack  120  according to another embodiment of the present invention. Rack  120  has both a curved portion  122  and a linear portion  124 . Referring now to FIG. 6, a retractor  100  according to this second embodiment is shown. Retractor  100  includes a first arm  140  and a second arm  160 . Preferably, when configured with both a curved portion  122  and a linear portion  124 , both first and second arms  140 ,  160  are adjustable with respect to their position along the rack  120 , and/or include means to traverse the rack  120 . In this way, the retractor may be used either by positioning the arms  140 ,  160 , along the linear portion, to spread the ribs without lifting, or by using some or all of the curved portion, to provide lift as previously described, or some combination of both linear and curved portions.  
         [0029]    The present invention has been described herein with reference to certain preferred embodiments. These embodiments are offered as illustrative, and not limiting, of the scope of the invention. Certain modifications or alterations may be apparent to those skilled in the art without departing from the scope of the invention, which is defined by the appended claims.