Abstract:
A stabilizer for use in surgical procedures such as coronary bypass surgery includes an elongate, rigid handle, a neck at the end of the handle, a base leg connected to the end of the neck, and first and second spaced, generally flat fingers that are disposed generally parallel with each other and which lie in a plane disposed at an angle from the longitudinal axis of the handle. The fingers can be used to press against the surface of the heart to stabilize it during surgery. In another embodiment, the handle is in the form of a flexible member that can be adjusted in a variety of positions. In either embodiment, the attachment between the fingers and the heart can be enhanced by providing serrations for the underside of the fingers, or by making the fingers hollow and forming a plurality of openings in the underside of the fingers in order to apply a vacuum to the underside of the fingers.

Description:
This application is a continuation of application Ser. No. 09/049,597, filed Mar. 27, 1998, now U.S. Pat. No. 5,967,972, which claims priority from provisional application No. 60/042,472, filed Mar. 28, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to retractors that are used in various types of surgeries such as cardiovascular surgery and, more particularly, to a retractor that permits such operations to be conducted with minimal trauma to the patient. 
     2. Reference to Provisional Application 
     Reference is made to provisional application Ser. No. 60/042,472, filed Mar. 28, 1997, the disclosure of which is incorporated herein by reference and from which priority is claimed. 
     3. Description of the Prior Art 
     In the course of such operative procedures as mitral valve surgery, it is necessary to expose the heart. Such exposure traditionally has been accomplished by performing a sternotomy (cutting an incision completely through the sternum and retracting the sternum). The retraction is accomplished by a retractor that employs parallel grips that engage the edges of the separated sternum. The grips are mounted perpendicularly to a toothed crossbar. One of the grips is fixed to one end of the crossbar, while the other grip is movably mounted to the crossbar by means of a pinion that engages the teeth of the crossbar. Upon rotating the pinion, the movable grip can be moved away from the fixed grip, thereby retracting the sternum so as to expose the heart. A retractor of the type described is shown in U.S. Re. 34,150, issued Dec. 29, 1992 to A. E. Santilli and D. M. Cosgrove III (“the &#39;150 patent”), the disclosure of which is incorporated herein by reference. 
     After the sternum has been retracted, it is necessary to retract portions of the heart in order to expose diseased or defective parts thereof. Such retraction has been accomplished by attaching a cardiovascular retractor to one of the grips of the sternum retractor. The cardiovascular retractor, in preferred form, includes a horizontal rod to which retractor blades having elongate handles are attached by means of universal clamps. The rod is spaced above the grip a considerable distance in order to permit the blades to have access to the heart at a favorable angle. The blades can be moved so as to engage portions of the heart to be retracted. Thereafter, upon pulling the blades and locking them in place by tightening the universal clamps, the heart can be retracted in any manner desired and maintained in that position as long as necessary. 
     The blades in the described construction can be moved back and forth, up and down, side to side, and they can be pivoted about the longitudinal axis of the handle. Such versatility enables the device to be used for virtually any type of heart operation where retraction is required. A preferred example of the device in question is disclosed in the &#39;150 patent. 
     While the retractor disclosed in the &#39;150 patent is effective for retraction of the sternum and subsequent retraction of the heart, unfortunately the operative technique is very invasive. That is, the splitting of the sternum coupled with its retraction is an extremely traumatic procedure. The recovery time from such a procedure can be significant. Further, the patient will experience considerable pain and discomfort during the recovery process. It is possible that the trauma associated with the process can have a negative impact on the patient&#39;s recovery from the operation. 
     Desirably, a retractor would exist that would permit surgical procedures to be performed that are less invasive than are possible with presently available retractors. Preferably, any such retractor would be relatively small and lightweight compared with prior retractors. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a new and improved retractor is disclosed that is minimally invasive. The invention also includes a new and improved method of retraction. By using the present invention, the heart can be accessed through a small incision between the ribs on the left side of the chest, usually between the third and fourth ribs. The right side of the chest also can opened in this manner for various purposes such as harvesting the right-side mammary artery. If it is desired to approach the heart through the sternum, only a small opening in the sternum is required. Further, the present invention permits certain heart operations to be performed without the need to stop the heart and use a heart-lung machine. In addition to heart surgeries, the present invention also enables other types of operations to be performed more effectively that has been possible heretofore. 
     The retractor according to the invention is provided in two embodiments for use in different surgical procedures as the surgeon may determine. In one embodiment, the retractor includes a pair of small grips, or paddles, that are mounted to an elongate crossbar. The grips are disposed at the ends of arms that are connected removably to blocks that are connected to the crossbar. One of the blocks is fixed to one end of the crossbar, while the other block is movable along the crossbar so as to move toward or away from the fixed grip. The movable block is moved along the crossbar by means of a pinion that engages teeth on the crossbar. The pinion has a handle (or wrench) in order to permit the block to be moved readily. 
     The crossbar in the present invention includes a hinge disposed at a location between its ends and between the spaced grips. The hinge is movable about an axis that is perpendicular to the longitudinal axis of the toothed portion of the crossbar and parallel to, or coincident with, a plane in which the toothed portion of the crossbar lies. Accordingly, the hinge enables one end of the crossbar to be pivoted which, in turn, enables the fixed grip to be pivoted relative to the movable grip. Preferably, the hinge enables the fixed grip to be moved through an angle of +45 degrees and −45 degrees relative to the longitudinal axis of the toothed portion of the crossbar. 
     The invention includes means for pivoting the fixed grip about the axis of the hinge. The means for pivoting can take two forms. In the first form, a first, vertically extending bracket is secured removably to one of the blocks and a second, vertically extending bracket is secured removably to the other block. An elongate rod having first and second opposed ends is pivotally connected at its first end to the first bracket and adjustably connected at its second end to the second bracket. Preferably, the second bracket includes an opening through which the second end of the rod extends. The second end of the rod is threaded and carries a nut for engaging the second bracket. 
     When the crossbar is positioned in a straight line, i.e., not pivoted, the rod is parallel to the longitudinal axis of the crossbar. The rod is connected to the brackets such that it is disposed above the crossbar a desired amount. When the nut is tightened and/or when the grips are moved apart, the fixed grip will be pivoted relative to the movable grip. 
     The invention also includes so-called side arm attachments. These attachments are elongate rods that can be removably attached to either of the arms. The rods enable one or more retractor blades of conventional design having elongate handles to be used to retract portions of the heart. Each retractor blade is connected to a selected rod by means of a universal clamp that encircles the handle of the blade and which is attached to the rod. Each clamp includes a nut that enables the clamp to be tightened or loosened with one hand. The clamps permit the blades to be moved to any position that may be desired by the surgeon. 
     The invention is especially effective for certain types of heart surgeries when employing a retractor blade known as a stabilizer. The stabilizer in question has an elongate handle to which a pair of spaced, parallel, generally flat fingers are connected at one end. The fingers lie in a plane disposed at an angle of approximately 125 degrees from the longitudinal axis of the handle. The stabilizer enables the heart to be compressed so as to be rendered relatively motionless. The region of the heart between the spaced-apart fingers will be relatively starved for blood, thereby permitting surgery to be performed without the need for a heart-lung machine to stop the heart. In order to accommodate different operative conditions, the stabilizer can be provided with malleable fingers, a malleable neck, or with an adjustable ball and socket connection between the handle and the fingers. 
     A particularly effective technique for supporting the stabilizer is to provide a housing that can be connected to a selected block. The stabilizer is connected to the housing by a flexible member that can be secured in a rigid position when desired. Preferably, the flexible member includes a plurality of generally tubular members disposed in end-to-end relationship, a cam disposed within the housing, a fitting (to which the stabilizer is connected) disposed at the end of the generally tubular members, and a cable extending through the generally tubular members. Upon activating the cam, the cable will be tightened or loosened, thereby securing the stabilizer in place or permitting it to be moved. An adjustment mechanism also can be provided for pre-tensioning the generally tubular members. 
     In a second embodiment of the invention, both blocks are movably mounted on the crossbar. This permits each arm with its respective grip to be positioned at any desired location relative to the hinge. 
     The invention also includes a second form of the means for pivoting the crossbar. The second form includes first and second brackets that are connected to the first and second blocks, respectively. The brackets are connected by a toothed rod, or rack, that is affixed to one of the brackets and which extends through an opening in the other bracket. The other bracket includes a pinion that can be rotated by a wingnut. A spring-biased pawl prevents the brackets from moving away from each other while permitting the brackets to move toward each other, thereby causing the crossbar to be pivoted. 
     The method according to the invention comprises a particular technique for retracting the patient&#39;s ribs or sternum most effectively. The method in question involves compressing the distal ribs, while retracting and raising the adjacent proximal ribs. This result is accomplished by orienting the crossbar such that the movable grip is on the distal side of the patient. 
     Initially, the hinge is positioned to provide a straight crossbar and the grips are moved together in order to insert them between the ribs. The means for pivoting is actuated in order to pivot the fixed, or proximal, grip about the axis of the hinge. Then, the grips are moved apart by moving the distal grip along the crossbar. As the distal grip is moved, the grips are spaced further apart and the proximal grip is raised even further. Such retraction provides adequate access to the heart despite the small incision between the ribs. 
     The retractor according to the invention can be used for operations on either side of the chest. By orienting the crossbar appropriately, the retractor can always be positioned to compress the distal ribs and retract and raise the proximal ribs. A similar result can be obtained with incisions through the sternum, that is, appropriate positioning of the blocks and brackets will enable either side of the sternum to be retracted and raised as may be desired. 
     As will be appreciated from the foregoing description, the retractor according to the invention is minimally invasive. By using the retractor according to the invention, adequate access to the heart can be obtained merely by making a small incision between two adjacent ribs. There is no need to completely split the patient&#39;s sternum in order to have access to the heart. The foregoing results are obtained by using very small grips and using the retractor first as a rib-spreader (or sternum, spreader) and then as a proximal rib-lifter (or sternum lifter). Once the ribs or sternum have been retracted and raised properly, various attachments can be connected to the retractor for purposes of cardiovascular retraction and other purposes. 
     The retractor according to the invention also can be used for other types of surgeries, such as spinal implant surgery. The retractor can be used for both anterior and posterior spinal implant surgery. The ability to pivot and displace the fixed grip relative to the movable grip is a significant advantage compared with existing retractors. Further, because the grip-carrying arms are removably connected to the retractor, it is possible to substitute differently configured grips to conduct different types of surgical procedures, to conduct surgical procedures on different sizes of people, or to perform different types of retractions during the course of the same surgical procedure. Such substitutions can be accomplished quickly and easily, thereby enhancing the versatility of the retractor. 
     The foregoing features and advantages will be apparent from the accompanying drawings and the description that follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of an assembled retractor according to the invention showing a movable block, a fixed block, and a toothed-rod pivoting device; 
     FIG. 2 is a front elevational view of the retractor of FIG. 1; 
     FIG. 3 is a side elevational view of the retractor of FIG. 1; 
     FIG. 4 is a perspective view of the retractor of FIG. 1 without a pivoting device and with different grips; 
     FIG. 5 is a perspective view of the retractor of FIG. 1 with a threaded-rod pivoting device and different grips; 
     FIG. 6 is a perspective view of the retractor of FIG. 1 without a pivoting device and with a stabilizer held in place by a selectively flexible holder; 
     FIG. 7 is a perspective view of the retractor of FIG. 1 without a pivoting device and with a stabilizer held in place by a clamp that is connected to an arm-mounted rod; 
     FIG. 8 is a perspective view of the retractor according to the invention showing two grips being supported by movable blocks and a lock for connecting portions of a crossbar; 
     FIG. 9 is a perspective view showing various grips usable with the invention; 
     FIG. 10 is a perspective view of an L-shaped rod with pins for attachment to a block-mounted arm, a pinion for activating a block, and a wrench for the pinion; 
     FIG. 11 is a side elevational view of a retractor in the form of a stabilizer and a flexible holder therefor in accordance with the invention; 
     FIG. 12 is a cross-sectional view of the holder of FIG. 11; 
     FIGS. 13 and 14 are cross-sectional views of a portion of the holder of FIG. 11 showing a cable-tightening cam in tightened and loosened positions; 
     FIG. 15 is an end view of the holder of FIG. 11 taken along a plane indicated by line  15 — 15 ; 
     FIG. 16 is a perspective view of another embodiment of a stabilizer having a suction capability; 
     FIG. 17 is a perspective view of the stabilizer of FIG. 11; 
     FIGS. 18,  19 , and  20  are perspective, side, and bottom views, respectively, of a stabilizer according to the invention having a malleable neck; 
     FIGS. 21,  22 , and  23  are perspective, side, and bottom views, respectively, of another embodiment of a stabilizer according to the invention having a rigid neck; and 
     FIGS. 24,  25 ,  26 , and  27  are perspective, side, and cross-sectional views, respectively, of another embodiment of a stabilizer according to the invention having a ball-and-socket adjustable neck. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring particularly to FIGS. 1-3, a retractor according to the invention is indicated by the reference numeral  10 . In the description that follows, reference should be made to the various other Figures, where appropriate, for a more detailed understanding of the individual components that are used with the invention. 
     The retractor  10  includes a pair of small, parallel grips  12 ,  14 , or paddles, that are mounted to an elongate crossbar  16 . The crossbar  16  includes a toothed portion  18  having a longitudinal axis  19  and a non-toothed portion  20  having a longitudinal axis  21 . The crossbar  16  includes a locking, adjustable hinge  22  that connects the portions  18 ,  20  at a location between the spaced grips  12 ,  14 . The hinge  22  pivots about an axis  23  that is perpendicular to the longitudinal axis  19  of the portion  18  and parallel to, or coincident with, a plane in which the axis  19  lies. 
     The hinge  22  enables the portion  20  to be pivoted relative to the portion  18  which, in turn, enables the grip  14  to be pivoted relative to the grip  12 . Preferably, the hinge  22  enables the grip  12  to be moved through an angle of + 45  degrees and - 45  degrees relative to the longitudinal axis  19 . The hinge  22  includes a lock  24  that can be tightened to prevent movement of the hinge  22  when a desired position of the grips  12 ,  14  has been attained. 
     The grips  12 ,  14  are disposed at the ends of arms  28 ,  30  that extend away from the crossbar  16 . The arms  28 ,  30  are connected removably to blocks  32 ,  34 , respectively, that are connected to the portions  18 ,  20 . The block  34  is fixed to the portion  20 , while the block  32  is movable along the portion  18  so as to move the grip  12  toward or away from the grip  14 . Movement of the block  32  is accomplished by a pinion  36  that engages the teeth of the portion  18 . A handle  38  is provided to rotate the pinion  36 . 
     The invention includes a pivoting device for pivoting the grip  14  about the axis  28  of the hinge  26 . The pivoting device in the preferred embodiment includes a first, vertically extending bracket  40  having a U-shaped {fraction (3/16)} inch steel rod  42 . A second, vertically extending bracket  44  also has a U-shaped {fraction (3/16)} inch steel rod  46 . The term “vertically” is used herein for purposes of convenience of description only. It is to be understood that the retractor  10  can be oriented in different positions, and the use of such terms of orientation as “vertically” is not to be construed as a limitation on the possible uses or orientations of the retractor  10 . 
     The upper surfaces of the blocks  32 ,  34  each include an upside-down L-shaped bar  47 . The bars  47  are welded or otherwise secured to the upper surfaces of the blocks  32 ,  34 . The bars  47  are aligned along axes parallel to the axis  23  of the hinge  22 , i.e., perpendicular to the longitudinal axes  19 ,  21 . The undercut portions of the bars  47  face away from each other. The undercut portions are large enough to receive the rods  42 ,  46 . 
     An elongate rod  48  is securely connected at one end to the first bracket  40 . The second bracket  44  includes an opening through which the other end of the rod  48  extends. The upper surface of the rod  48  has a plurality of teeth  50 . The bracket  44  includes a pinion that is operated by a wingnut  52 . The pinion engages the teeth  50 . A spring-biased pawl  54  also engages the teeth  50 . As will be apparent from an examination of FIG. 2, the pawl  54  permits the brackets  40 ,  44  to be moved toward each other without interference, but prevents the brackets  40 ,  44  from being moved away from each other (unless released). When the lock  24  is loosened, the wingnut  52  can be rotated to cause the brackets  40 ,  44  to come closer together, thereby causing the grip  14  to be pivoted relative to the grip  12 . 
     The blocks  32 ,  34  include slots adapted to receive the arms  28 ,  30 . The arms  28 ,  30  are retained in the slots by notches (FIG. 9) that are engaged by spring-biased pins  56  included as part of the blocks  32 ,  34 . Upon retracting the pins  56 , the arms  28 ,  30  can be removed. Accordingly, the grips  12 ,  14  can be replaced quickly and conveniently by grips suited for other purposes. Grips of different configurations for different surgical procedures are shown in FIGS. 4-9. Some of the distal grips (FIGS. 5 and 9) includes malleable upper portions with rectangular openings that can be moved to different positions as the surgeon deems necessary. 
     The retractor  10  includes an external lock  60  for the crossbar  16 . Referring to FIGS.  4  and  6 - 8 , the lock  60  includes a plurality of prongs  62  that are fitted over the crossbar  16  on either side of the hinge  22 . The prongs  62  extended from a base plate  64  having an opening therein. A threaded pin  66  extends through the opening and into an opening  58  included as part of the hinge  22  in order to securely attach the lock  60  to the crossbar  16 . 
     A rod  68  (FIGS.7 and 10) can be attached to either of the arms  28 ,  30 . The rod  68  preferably is L-shaped, although other configurations are possible. The rod  68  includes a pair of small pins  70  that project form one side thereof. The arms  28 ,  30  each include a pair of spaced openings  72  in the upper surfaces thereof (FIGS.  4 - 9 ). The pins  70  can be fitted into the openings  72  to attach the rod  68  to one of the arms  28 ,  30 . 
     The rod  68  enables one or more retractor bladed of conventional design having elongated handles to be used to retract portions of the heart. Each retractor blade is connected to the rod  68  by means of a universal clamp  74  that encircles both the handle of the blade and the rod (FIG.  7 ). Each clamp  74  includes a nut  76  that enables the clamp  74  to be tightened or loosened with one hand. The clamps  74  permit the blades to be moved to any position that may be desired by the surgeon and quickly and easily locked in place there. Force applied to the rod  68  by the retractor blade and the clamp  74  biases the pins  70  in the openings  72 , thereby preventing the rod  68  from being dislodged. 
     The invention is effective with a particular type of retractor blade  80  known as a stabilizer. Referring to FIGS.  7  and  18 - 20 , one form of the stabilizer  80  had an elongate handle  82  to which a pair of spaced, parallel, generally flat fingers  84  are connected at one end. The fingers  84  lie in a plane disposed at an angle of approximately 125 degrees from the longitudinal axis of the handle  82  (see FIG.  19 ). The fingers  84  are connected to the handle  82  by a malleable neck  86  and a base leg  88 , thus permitting the angular relationship between the fingers  84  and the handle  82  to be changed as the surgeon may see fit. If desired, the fingers  84  also can be made of a malleable material for purposes of adjustment. The underside of the fingers  84  are serrated and distal ends  89  are angled toward each other. The retractor blade  80  enables the heart to be compressed. The region of the heart between the spaced apart fingers  84  will be relatively starved for blood, thereby permitting surgery to be performed without the need for a heart-lung machine to stop the heart. 
     Another form of the stabilizer  80  is shown in FIGS. 21-23, and is identified by the reference numeral  90 . The stabilizer  90  shown if FIGS. 21-23 is similar to the stabilizer shown  80  in FIGS.  7  and  18 - 20 , except that the neck is not malleable. The neck  86  includes two portions  92  that provide extra support for the fingers  84 . Also, the distal ends  89  are inclined upwardly from the plane in which the fingers  84  lie. 
     Yet another form of the stabilizer  80  is shown in FIGS. 24-27, and is identified by the reference numeral  94 . In this version of the stabilizer  80 , the neck  86  includes a ball  96  that is fitted into a socket  98  included as part of a threaded sleeve  100 . The sleeve  100  is threaded onto the end of the handle  82  in order to compress the ball  96  within the socket  98 . By tightening or loosening the sleeve  100 , the ball  96  will be compressed or released. In turn, the position of the fingers  84  relative to the handle  82  can be adjusted as the surgeon may deem necessary. 
     The various stabilizer versions described heretofore include a handle  82  that can be connected to the rod  68  shown in FIGS. 7 and 10 by means of a universal clamp  74 . Yet another version of the stabilizer  80  is shown in FIGS.  6  and  11 - 17 , and is identified by the reference numeral  102 . The stabilizer  102  is connected to the retractor  10  by a different technique. In this version of the stabilizer  80 , a selectively flexible connection between the neck  86  and a selected block  32 ,  34  is established. The connection includes a housing  104  from which a threaded fitting  106  extends. A nut  108  and a locknut  110  are threaded onto the fitting  106 . A plurality of generally tubular members  112  are disposed in end-to-end relationship. The neck  86  of the stabilizer  102  is connected to a fitting  114  at the end of the tubular members  112  by means of a threaded pin  116 . A cable  118  is connected to the fitting  114  and is threaded through the tubular members  112 , through the fitting  106 , and into the housing  104 . The end of the cable includes a formation  120  having an opening  122  therein. A cam (eccentric)  124  is disposed within the opening  122  (FIGS.  13  and  14 ). A handle  126  is connected to the cam  124  and is disposed outside the housing  104 . 
     Referring to FIG. 15, the housing  104  includes a longitudinally extending “T-slot”  128  that opens through the lower face of the housing  104 . The T-slot  128  can be fitted over one of the bars  47  and secured there by tightening a set screw  130  that opens into the upper portion of the T-slot  128 . As will be apparent from an examination of FIGS. 11-15, the tension on the cable  118 , and hence the compression force applied to the tubular members  112 , can be pre-set by adjusting the nut  108  and the locknut  110  that are threaded onto the fitting  106  projecting from the housing  104 . Thereafter, the tension on the cable  118  can be increased even more by rotating the handle  126  to move the cam  124  and the formation  120 . 
     Referring particularly to FIG. 16, the fingers  84  can be made hollow with openings  132  on the underside. A hollow tube (or handle)  134  is connected to the fingers. A vacuum can be applied to the fingers  84  through the tube (or handle)  134  in order to withdraw blood or other fluids through the openings  132  in the fingers  84 . 
     Referring to FIG. 10, an extra pinion  136  is shown. The pinion  136  includes a drive opening in the form of a hexagonal socket  138 . The invention also includes a wrench  140  having a hexagonal end  142  for establishing a driving connection with the pinion  136 . If desired, the handles and pinions  36 ,  38  shown in FIG. 8 can be removed from the blocks  32 ,  34  upon advancing the blocks  32 ,  34  beyond the ends of the crossbar  16  (to disengage the teeth). At that point, the pinions  36 , with handles  38  attached, can be removed from the blocks  32 ,  34 . Then, pinion  136  as shown in FIG. 10 can be inserted into the blocks  32 ,  34 . The wrench  140  then can be used to move the blocks  32 ,  34  back and forth on the crossbar  16 . The use of this unobtrusive pinion  136  is preferred in situations where space is at a premium or the handles  38  otherwise might be considered to be obstructive. 
     Referring now to FIG. 5, another form of pivoting device is shown. The device includes a first bracket  144  extending vertically upwardly from the block  32  to which an elongate, threaded rod  146  is pivotally connected at the upper end thereof. A second bracket  148  is connected to the block  34  and extends vertically upwardly therefrom. The second bracket  148  includes an opening through which the rod  146  extends. A nut  150  is threaded onto the rod  146 . The opening is rounded on that side engaged by the nut  150 . The nut  150  also is rounded on that end which engages the bracket  148 . 
     As will be apparent from an examination of FIG. 5, tightening or loosening of the nut  150  will cause the brackets  144 ,  148  to be moved closer to each other or further apart. In turn, the grips  12 ,  14  will be pivoted relative to each other. That portion of the rod  146  that extends between the brackets  144 ,  148  is largely unthreaded. Accordingly, the rod  146  can receive retractor blade-supporting clamps  74  at a location between the brackets  144 ,  148 . This feature provides an extra degree of versatility for the surgeon. 
     The method according to the invention comprises a particular technique for retracting the patient&#39;s ribs or sternum most effectively. The method in question involves compressing the distal ribs (usually the fourth and fifth ribs), while retracting and raising the adjacent proximal ribs (usually the second and third ribs). This result is accomplished by orienting the crossbar  16  such that the movable grip  12  is on the distal side of the patient. 
     Initially, the hinge  22  is positioned to provide a straight crossbar and the grips  12 ,  14  are moved together in order to insert them between the ribs. The means for pivoting is actuated in order to pivot the fixed, or proximal, grip  14  about the axis of the hinge  22 . Then, the grips  12 ,  14  are moved apart by moving the distal grip  12  along the crossbar  16 . As the distal grip is moved, the grips  12 ,  14  are spaced further apart and the proximal grip  14  is raised even further. Such retraction provides adequate access to the heart despite the small incision between the ribs. 
     The retractor  10  according to the invention can be used for operations on either side of the chest. By orienting the crossbar  16  appropriately, the retractor  10  can always be positioned to compress the distal ribs and retract and raise the proximal ribs. A similar result can be obtained with incisions through the sternum, that is, appropriate positioning of the blocks  32 ,  34  and brackets  40 ,  44  will enable either side of the sternum to be retracted and raised as may be desired. 
     As will be appreciated from the foregoing description, the retractor  10  according to the invention is minimally invasive. By using the retractor  10  according to the invention, there is no need to perform a full sternotomy in order to have access to the heart. The foregoing results are obtained by using very small grips  12 ,  14  and using the retractor first as a rib-spreader and then as a proximal rib-lifter. Once the ribs have been retracted and raised properly, various attachments can be connected to the retractor  10  for purposes of cardiovascular retraction and other purposes. 
     The retractor  10  according to the invention also can be used for other types of surgeries, such as spinal implant surgery. The retractor  10  can be used for both anterior and posterior spinal implant surgery. The ability to pivot the grips  12 ,  14  relative to each other is a significant advantage compared with existing retractors. Further, because the grip-carrying arms  28 ,  30  are removably connected to the retractor  10 , it is possible to substitute different grips  12 ,  14  to conduct different types of surgical procedure. Such substitutions can be accomplished quickly and easily, thereby enhancing the versatility of the retractor. 
     Although the invention has been described in its preferred form with a certain degree of particularity, it will be understood that the present disclosure of the preferred embodiment has been made only by way of example and that various changes may be resorted to without departing from the true spirit and scope of the invention as hereinafter claimed. It is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty exist in the invention disclosed.