Abstract:
Disclosed is a device for isolating a cardiac surgical site. The device includes a first finger having a clinging accessory for attaching the first finger to a heart, a second finger having a clinging accessory for attaching the second finger to the heart, a first joint disposed on the first finger so that the first finger may rotate on a surface of the heart such that the rotation stretches a surgical site, a first stopper disposed on the first finger for preventing undesired rotation of the first finger to isolate the surgical site, and a link for coupling the first finger to the second finger. Also disclosed is a method of isolating a cardiac surgical site. The method includes the steps of disposing a first finger on a heart, clinging the first finger to the heart surface, disposing a second finger on a heart, clinging the second finger to the heart surface, and then rotating the first finger for achieving selective isolation of the heart surface.

Description:
This application claims priority under 35 USC§ 119(e)(1) of provisional application number 60/143,023 filed on Jul. 09, 1999. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to medical surgical devices, and more particularly to a device and method of stabilizing a surgical site during cardiac or cardiovascular surgery. 
     BACKGROUND OF THE INVENTION 
     Heart disease and associated cardiovascular problems have become so common in the United States that over 400,000 open heart surgeries are performed each year. Traditionally, physicians would open the chest and stop the heart before performing a surgical procedure on the heart. However, medical practices have improved, and physicians now recognize that there are advantages to performing surgery on a beating heart. For example, performing surgery on a beating heart avoids the necessity to expose the heart to filters, oxygenators, tubes, and other devices. This decreases the trauma associated with stopping the heart, as well as avoids other dangers that stopping the heart poses to a patient. In addition, by avoiding the use of these devices, the physician can lower the expense of an operation. Furthermore, performing surgery on a beating heart lowers the risk of ischemic damage to heart and surrounding tissue. 
     Unfortunately, there are many difficulties and challenges which must be overcome to successfully perform surgery on a beating heart. For example, every time the heart beats, the heart moves. This makes it difficult to isolate a specific site on the heart for surgery. Furthermore, physicians typically must develop great skill and expertise to accommodate the movement of the heart with existing instruments which were designed for use with a heart that is stopped. Because of the increased demands of performing surgery on a beating heart, surgery on a beating heart often takes longer than surgery on a stopped heart. Fortunately, devices and methods are being developed which decrease the amount of time and expertise it takes to identify and isolate a target vessel and thus, reduce the time it takes to perform open heart surgery. 
     One family of instruments which have been developed to facilitate surgery on a beating heart are known as cardiac immobilization devices (devices). A number of these devices function by attaching to the heart at two or more points. The points are then moved further apart, thus stretching the surface area of the heart about which surgery is to be performed (surgical site). The devices typically grip the heart surface by suction. Unfortunately, there are a number of disadvantages associated with these methods of isolating a surgical site. 
     Some cardiac immobilization devices often appear to be little more than steak tongs or clamps which have been slightly altered to attach to a heart surface. Other devices use flex links or rods to attach to a retractor and then use a metallic foot to stabilize the heart surface. Suction devices may comprise a plurality of suction cups, or may have at least one hollow cylinder with holes in it, which is then attached to a pump which pulls a vacuum at the holes. 
     FIG. 1A (prior art) shows a cardiac immobilization device  130  attached to a heart surface  140 . To perform open heart surgery, typically a chest retractor  110  is braced within a rib cage and used to maintain an opening in the chest wall  112  which provides access to the heart surface  140 . A stabilizing member, such as a flexible arm assembly  120  is used to securely locate a cardiac immobilization device  130  upon the heart surface  140 . Accordingly, the stabilizing member  120  is coupled to the retractor  110  via a clamp  126  and holds the cardiac immobilization device  130  in a predetermined position. 
     The flexible arm assembly  120  includes a flexible arm  124  which may be bent and twisted into various shapes and geometries to access different locations on the heart surface  140 . At the end of the flexible arm  124  closest to the heart surface  140  is a socket  128  for attaching the flexible arm  124  to the cardiac immobilization device  130 . At the other end of the flexible arm  124  is a handle  122  which when turned tightens a cable (not shown) within the flexible arm  124 . The tightening of the cable makes the flexible arm  124  rigid and immobile. The tightening of the cable also tightens the socket  128 , allowing the socket  128  to grip an object, such as a ball  132  (the ball  132  is part of the cardiac immobilization device  130 ). 
     The shown cardiac immobilization device  130  uses suction to attach to a surface of the heart  140 . To attach the cardiac immobilization device  130  to the heart surface  140 , the cardiac immobilization device  130  utilizes a foot plate  136  with holes thereunder (not shown) on which a vacuum is placed. The vacuum is maintained by air hoses  134  which are attached to an air pump (not shown) and the foot plate  136 . Thus, the cardiac immobilization device  130  is held stationary on the heart surface  140  at the end of the flexible arm  124  of the flexible arm assembly  120  so that the heart surface  140  located within the foot plate  136  can be isolated. 
     One disadvantage of many tong type attachments is that they provide an uneven spread (the heart surface closest to the tong&#39;s hinge point is spread a smaller distance than the heart surface at the end of the tong). 
     There are also many disadvantages associated with using suction to isolate a surgical site. For example, many patients have a heart which is surrounded with fatty tissue. Since the fat surrounding the heart moves, when a physician uses a suction device to isolate a heart surface, the suction cups or suction holes attach to the fat (rather than the heart surface). The operative result of the device attaching to the fatty tissue is that the heart surface can still beat underneath the fatty tissue, which means that isolation and stabilization of the surgical site is poor. Furthermore, the fatty tissue may be drawn into the device (at a hole, for example) by the suction, and may clog the suction device thereby stopping suction at the holes which are further along and at the end of the device. In addition, after attachment to the heart is made with a suction device, the ability to spread the heart surface is limited by the force of suction on the heart surface. Should the suction break, the device must be repositioned and reattached to the heart, which consumes time and is a nuisance to the physician. Furthermore, when strong enough suction is applied to the heart surface to achieve adequate spreading and to prevent slippage, the suction can cause blood to accumulate and clot just beneath the heart surface, a hematoma (this condition is also commonly referred to as a “heart hickie”). 
     Therefore, what is needed is a device and method of isolating a surgical site for cardiac and cardiovascular surgery. The device should contact a minimal surface of the heart, accommodate the non-planar geometry of the heart, grip the heart firmly, yet gently, and should be easy to apply to and to remove from a beating heart. The present invention provides such a device and method. 
     SUMMARY OF THE INVENTION 
     The present invention provides a device and method for isolating a heart surface, particularly, the surface of a beating heart during cardiovascular surgery. The device utilizes rotation to attach to the heart surface and then spread the heart which isolates the spread portion of the heart for surgery. 
     Disclosed is a device for isolating a cardiac surgical site. The device generally comprises a first finger (which may be cylindrical) having a clinging accessory for attaching the first finger to a heart. Furthermore the device could comprise a second finger having a clinging accessory for attaching the second finger to the heart, a first joint disposed on the first finger so that the first finger may rotate on a surface of the heart such that said rotation stretches a surgical site, and a link for attaching the first finger to the second finger. In addition, a first stopper may be disposed on the first finger for preventing undesired rotation of the first finger to isolate the surgical site. 
     The accessory for attaching could comprise a plurality of tines, a plurality of suction points, or a rough textured surface such as a surface similar to sandpaper, for example. In addition, the first joint or a second joint (disposed on the second finger) could comprise a rotatable handle coupled in a sleeve. Furthermore, the first stopper or a second stopper (disposed on the second finger) could be configured such that the rotatable handle comprises at least one notch and the sleeve has at least one rib. Likewise, the first stopper or the second stopper (disposed on the second finger) could be configured such that the rotatable handle comprises at least one rib and the sleeve has at least one notch. The handle could comprise an O-ring groove for securing an O-ring about an end of the handle. 
     The link could comprise a ball and socket joint disposed between the first finger and the second finger for providing multi-axis articulation of the first finger and the second finger, as well as a first attachment bar coupled between the first handle and the ball and socket joint, and a second attachment bar coupled between the second handle and the ball and socket joint. Conversely, the link could comprise a first ball and socket joint associated with the first handle, a second ball and socket joint associated with the second handle, and an attachment bar for coupling the first ball and socket joint to the second ball and socket joint. 
     More generally, the present invention provides a means for isolating a cardiac surgical site. The means for isolating comprises a first support means, such as a finger or a functional equivalent, having a clinging means for attaching the first support means to a heart, and a second support means, such as a second finger or a functional equivalent, having a clinging means for attaching the second support means to the heart. The means for isolating also includes a rotating means, such as a cylinder or a functional equivalent, disposed on the first support means so that the first support means may rotate on a surface of the heart, a locking means, such as a rib and notch, or a functional equivalent, disposed on the first support means for preventing undesired rotation of the first support means. An attaching means, such as a link or a functional equivalent, connects the first support means to the second support means. 
     In another embodiment, the present invention provides a method of isolating a cardiac surgical site. The method comprises disposing a first finger on a heart, clinging the first finger to the heart surface, disposing a second finger on a heart, clinging the second finger to the heart surface, and rotating the first finger for achieving selective isolation of cardiac tissue. The method may further comprise rotating the second finger, locking the first finger to prevent rotation, or locking the second finger to prevent rotation. The method may also provide that clinging comprises penetrating the surface of the heart, applying suction to the surface of the heart, or applying an abrasive surface for frictionally gripping the surface of the heart. In addition, when applying a finger, the method may further comprise the step of compressing the finger onto the heart surface. Furthermore, the method could include the step of elevating the finger while maintaining its attachment to the heart surface. 
     The rotational action of the present invention allows the physician to overcome problems associated with fatty tissue on the heart surface, to adjust the spread of the heart surface during surgery, and to attach and detach the present invention from the heart quickly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other aspects of the invention, including specific embodiments, are understood by reference to the following detailed description taken in conjunction with the drawings in which: 
     FIG. 1A (prior art) shows a cardiac immobilization device attached to a heart surface; 
     FIG. 1 is an isometric view of one embodiment of a device according to the teachings of the present invention; 
     FIG. 2 shows a side view of the device shown in FIG. 1; 
     FIG. 3 is an exploded view of one arm of the device of FIG. 1; 
     FIG. 4 is a front view of the finger having tines attached to the holes; 
     FIG. 5 is a cut rear view of the handle taken along line  5 — 5  of FIG. 3; 
     FIG. 6 shows the sleeve in greater detail; 
     FIG. 7 is a cut side view of an arm in a locking position where the locking position is defined as the position of the device when the rib is set in a notch; 
     FIG. 8 illustrates the sleeve relative to the handle when the device is in a rotatable position; and 
     FIG. 9 is a flow diagram of one method of practicing the present invention. 
    
    
     References in the detailed description correspond to like references in the figures unless otherwise indicated. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention provides devices and methods for isolating a heart surface, and particularly the surface of a beating heart, during cardiovascular surgery. The device attaches to the heart surface and then utilizes rotation to spread the heart and isolate the spread portion of the heart (surgical site) for surgery. The rotational action of the present invention allows the physician to overcome problems associated with fatty tissue on the heart surface, to adjust the spread of and tension on the surgical site during surgery, and to attach and detach the device from the heart quickly. Other advantages and uses of the present invention will be apparent to those of ordinary skill in the art from the following description of the drawings. 
     FIG. 1 is an isometric view of one embodiment of a device according to the teachings of the present invention. The device generally comprises a pair of stainless steel fingers  10 ,  12  which are mounted in stainless steel handles  14 ,  16 . Of course, the fingers  10 ,  12  and the handles  14 , 16  may be made of any other material, such as plastics, rubber, other metals, or composite materials, for example. Furthermore, the fingers  10 ,  12  and the handles  14 ,  16  could be formed, cut or molded as a single unit. Stainless steel sleeves  20 ,  22  fit over the handles  14 ,  16  and are held in place about the handles  14 ,  16  by resilient O-rings  24 ,  26 . The combination of a finger, a handle, a sleeve, and an O-ring is called an “arm.” To couple two arms together, the sleeves,  20 ,  22  are attached together by a link  18  which is shown in FIG. 1 as a ball and socket assembly, for example. 
     A link is any device or collection of devices used to associate a finger and a stabilization device, such as another finger. The link  18  of FIG. 1 comprises a stainless steel ball  17 , which is weldedly coupled to each sleeve  20 ,  22  by stainless steel attachment bars  19 . The ball  17  is securely fastened in a socket  128  of the flexible arm assembly  120  shown in figure Ia. Of course, other link devices may be used. For example, the link  18  could comprise an attachment bar alone. Likewise, stabilizing members may have a variety of designs, and these other designs may use other types of mechanical links to maintain a predetermined distance between the fingers. 
     FIG. 2 shows a side view of the device illustrated in FIG.  1 . Finger  10  has a plurality of tines  30  which function as a clinging accessory to attach the device to a heart surface. Accordingly, a clinging accessory provides a finger traction to a heart surface. Other clinging accessories (such as suction holes, suction cups, rough textured surfaces (such as sandpaper), barbs, or electrostatic attachment, for example) are well known in the art and may be adapted for use with the present invention. Also, the handle  14  has a knob  42  which extends higher than the sleeve  20  so that the physician may grasp and rotate the handle  14 . The sleeve  20  has a plurality of notches  50 , and the handle  14  has a rib  40  which fits securely inside of one notch  50 . Accordingly, the combination of the rib  40  and a notch  50  together form a stopper which may be set to prevent rotation of the fingers  10 ,  12  as discussed below. A better understanding of the form and function of the present invention may be gained by examining the devices&#39; individual components and their interrelations. 
     FIG. 3 is an exploded view of one arm of the device of FIG.  1 . In FIG. 3, the finger  10  is seen to possess a plurality of holes  32  which accept the tines  30 . Although three holes  32  and three tines  30  are shown in FIG. 3, it should be understood that the finger  10  may have any number of holes  32  and a corresponding number of tines  30 . The holes  32  are of sufficient depth so that the tines  30  may be attached therein with solder, glue or by other means. Although the finger  10  of FIG. 3 is shown to be cylindrical, it should be understood that a finger may have any geometry so long as it may attach to a heart surface and stretch a surgical site by rotating. Finger  10  also has an attachable portion  34  which fits securely in a cylinder  44  of the handle  14 . 
     The handle  14  has a grippable knob  42  which is capable of being securely grasped and turned. Abutting the grippable knob  42  is the rib  40 . At the other end of the handle  14  is a groove  48  which functions as an O-ring seat. The end of the handle  14  having the groove  48  is preferably shaped like a hemisphere to facilitate placing the O-ring  24  onto the groove  48 . 
     FIG. 4 is a front view of the finger  10  having tines  30  attached and holes  32 . From FIG. 4 it is seen that the tines  30  have a hook shape which minimizes heart surface penetration and which facilitates the release of the tines from the heart muscle. The tines are of a stiffness so that should a stretching rotation require the releasing of the tines from the heart surface, they may release without ripping the heart surface, and then re-penetrate the heart surface at a new location, if necessary. Also, it should be noted that the tines point generally in the direction of the grabbing rotation. Although four linear rows are shown in FIG. 4, the invention may have any number of rows which may include non-linear, or even apparently random, row formations. In one embodiment, the tines have a length of about one quarter inch. Of course, other methods of attachment are well known in the art. These include but are not limited to, rough textured surfaces such as sandpaper, barbs, electrostatics, and suction holes, for example. 
     FIG. 5 is a cut rear view of the handle  14  taken along line  5 — 5  of FIG.  3 . From this view it can be seen that the grippable knob  42  extends both above and below the cylinder  44 . The portion of the grippable knob  42  extending below the cylinder  44  forms a lip  46  which is of a width that matches the circumference of the sleeve  20  such that when the sleeve  20  fits over the cylinder  44  the outside of the lip  46  aligns with the outside of the sleeve  20 . This view also illustrates that the rib  40  is of a width and size to accommodate the notch  50 . 
     FIG. 6 shows the sleeve  20  in greater detail. As shown, sleeve  20  has a plurality of notches  50 . Although four notches are shown in FIG. 6, the sleeve  20  may have any number of notches  50  so that the rotation of the fingers may be held at varying degrees of rotation. In addition, one side of the sleeve  20  has a hole  54 , or other surface preparation, for accepting the attachment bar  19  (of course, the sleeve  20  may have other apertures attached to it depending on the link  18  used; likewise, the sleeve  20  may be connected to a link via welding, which avoids the need for apertures or modifications). The O-ring  24  pushes against the handle  14  so as to apply tension to the sleeve  20  to securely force a rib  40  over notch  50 , as described below. Accordingly, the sleeve  20  has a cylinder  56  which at the end opposite the notches  50  has a tapered lip  52  which is shaped to accept the O-ring  24  to minimize wear on the O-ring  24 . 
     FIG. 7 is a cut side view of an arm in a locking position where the locking position is defined as the position of the device when the rib  40  is set in a notch  50 . Also, when in the locking position, the sleeve  20  fits securely against the handle  14 . In the locking position, the O-ring  24  in groove  48  exerts a force upon the sleeve  20  to keep it in place abutting the handle  14 . Furthermore, note that the rib  40  also abuts the sleeve  20 , indicating that a notch  50  (not shown) is in position about the rib  40 , forming a stopper. 
     FIG. 8 illustrates the sleeve  20  relative to the handle  14  when the device is in a rotatable position. Here, it can be seen that the sleeve  20  is pushed against the O-ring  24 , causing distortion of the O-ring  24 . The separation of the sleeve  20  from the grippable knob  42  removes the notch  50  from the rib  40  and allows for the handle  14  to be rotated. Accordingly, as the handle  14  rotates so does the finger  10 . Then, depending on the direction of the rotation, the heart surface will either be stretched or compressed. 
     One method of implementing the present invention uses the above disclosed device. Accordingly, FIG. 9 is a flow diagram of one embodiment of a method according to the present invention. First, the chest cavity is cut and opened and held securely in place, typically by a chest retractor, in an expose heart and place retractor step  90 . As advances in open heart surgery are made, less intrusive means of exposing the heart for surgery will be developed and this method should in no way be read to limit its use to open chest cavities, or in the use of retractors. 
     Following the securing of the chest retractor, a flex arm with a finger  10  attached thereto is attached to the retractor in a fix flex arm step  91 . Next, the finger  10  is placed about the area of the heart on which surgery is to be performed in a finger placement step  92 . Then, the finger  10  is attached to the heart in a finger attachment step  94  and in a make flex arm rigid step  95 , the flex arm is made stiff, typically by tightening a knob attached to the flex arm. 
     The fingers  10 ,  12  may be placed together on the heart in a single finger placement step  92  and then attached to the heart in a single finger attachment step  94 , or each finger  10 ,  12  may be placed on the heart surface, and then attached to the heart surface independently of each other. In any event, the result is that the finger  10  lies on one side of the surgical site, and a second finger  12  lies generally on the opposite side of the surgical site. Optionally, to achieve better traction in a following rotation step, and thus better isolation of the heart surface, the fingers  10 , 12  may be gently pressed onto the heart (the fingers do not penetrate the heart surface). 
     Next, in a finger rotation step  96 , at least one finger is rotated in a direction which increases the surface tension of the heart surface across the surgical site until a desired tension is achieved across the surgical site area. Once the desired tension is achieved on the heart surface, the tension is maintained by locking the device in that current state of rotation in a position locking step  98 . Yet even better heart surface isolation may be achieved at this point by lifting the fingers  10 ,  12  (and thus the isolated heart surface) slightly. Surgery may then be performed at the isolated surgical site on the heart as well as on any veins or arteries going to or from the surgical site. If necessary, during surgery, the handles may be rotated in either a gripping or releasing direction to increase or decrease the tension at the surgical site. Then, after the surgery is completed, the above detailed steps may be reversed and the device removed. 
     Though the invention has been described with respect to a specific preferred embodiment, many variations and modifications will become apparent to those skilled in the art upon reading the present application. It is therefore the intention that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.