WO2001052717A2

WO2001052717A2 - Tissue stabilization device for use with surgical retractors

Info

Publication number: WO2001052717A2
Application number: PCT/US2001/001016
Authority: WO
Inventors: David Stefanchik; Christopher A. Papa; Douglas B. Hoffman; Jeffrey S. Swayze; Christopher M. George
Original assignee: Ethicon Endo-Surgery, Inc.
Priority date: 2000-01-19
Filing date: 2001-01-11
Publication date: 2001-07-26
Also published as: WO2001052717A3; AU2001230917A1

Abstract

The present invention is a device for stabilizing moving tissues or an organ such as the heart within the body during a surgical procedure such as a coronary artery bypass graft procedure. The device comprises a stem (65) having proximal and distal ends, a compressible ball (66) slideably attached onto the stem, and at least one foot (68 or 69) connected to the distal end of the stem. Each foot extends laterally from the stem and has a distal surface for placement on moving tissue (138). The device also comprises a retractor mount (20) with a first locking means for operational engagement with the compressible ball on the stem for adjustably holding the stem in a desired orientation during the surgical procedure. The device also comprises a second locking means for releaseably attaching the stem to the surgical retractor.

Description

TISSUE STABILIZATION DEVICE FOR USE WITH SURGICAL RETRACTORS

The present invention is related to the following: U.S. provisional patent application number 60/116581 filed on January 21, 1999; U.S. non-pro visonal patent application serial number 08/946,455 filed on October 7, 1997; U.S. Patent 5,865,730 issued on February 2, 1999; U.S. Patent 5,984,864 issued on November 16, 1999; and U.S. Patent 6,013,027 issued on January 11, 2000.

FIELD OF THE INVENTION

The present invention relates to surgical devices and methods that temporary immobilize moving tissue during a surgical procedure, and specifically to such devices and methods that are used to stabilize a beating heart during cardiovascular surgery.

BACKGROUND OF THE INVENTION

In many surgical procedures the surgeon must operate on moving organs or tissues within the human body. For example, surgeons now perform coronary artery bypass graft surgery on beating hearts, without using a cardiopulmonary bypass machine. The surgeon sutures a bypass graft (typically a segment of a vein or artery harvested from the patient) between the aorta and the occluded coronary artery to reestablish blood flow to the heart muscle. In a popular variation of the bypass procedure, the surgeon dissects an internal mammary artery (IMA) from the chest wall, and redirects its blood flow to the heart by suturing it to the lower anterior descending (LAD) artery of the heart. This life-saving operation reestablishes blood flow to the main pump, the left ventricle, of the heart.

For surgical procedures using one or more harvested vessel grafts, the surgeon sutures one end of each graft to the aorta or other major blood supply vessel (proximal anastomosis), and the other end to the coronary or other arteries of the heart, just distal to the blockage (distal anastomosis). Some surgeons choose to complete all of the proximal anastomoses before commencing the distal anastomoses.

In contrast, other surgeons choose to complete all of the distal anastomoses first.

Regardless of the order, when suturing the distal end of the graft vessel to the heart vessel, it is important to atraumatically steady the heart vessel while minimizing visual and surgical obstruction by instruments in the narrow operative field. This is also true when suturing the IMA to the LAD.

Working through a chest incision held open by a surgical retractor, the surgeon sutures the end of the graft or IMA vessel to an arteriotomy (opening created in the artery with a scalpel) on the side of the heart artery. The surgeon uses a pair of needle holding instruments to pass a curved needle through the tissues. Usually separate sutures are applied first at the heel and toe locations of the anastomosis to draw together and align the vessels. Then the surgeon applies a continuous "running" stitch on each half of the anastomosis between the heel and toe stitches. The surgeon sutures the vessels with great care to bring the vessels together intima-to-intima without dislodging plaque typically adhering to the inside of the diseased vessel.

A hand-sutured, anastomosis procedure on a non-beating heart and done through a conventional stemotomy (when the chest is incised at the sternum and spread apart with a surgical retractor to access the heart) generally takes the skilled surgeon from ten to twenty minutes to complete. To facilitate this procedure in the past, surgical assistants have used forceps and metal fork-type devices to push against a portion of the heart to keep it still as the surgeon was suturing. Obviously, this was a tiring task for the surgical assistant to hold such devices in place while trying to stay out of the surgeon's way during the procedure.

In recent years, several investigators have developed new devices for stabilizing the heart during coronary artery bypass. One example of such a device is disclosed in U.S. Patent 5,927,284 issued to Borst et al on July 27, 1999.. This vacuum-based, stabilization device has members for grabbing and lifting onto a portion of the heart by suction to immobilize it. A disadvantage of this device is that the members may become separated from the heart if, for example, vacuum supply is blocked or leaked.

Another example of a heart stabilization device is disclosed in U.S. Patent

5,947,896 issued to Sherts et al on September 7, 1999. A disadvantage of this device and others listed in the references cited is the stabilization device may be used only with a specialized surgical retractor provided with the stabilization device. Many surgeons, however, prefer to use available, reuseable surgical retractors. Reasons for this preference include the desire to reduce overall procedure costs, preference for a particular type of chest opening for the procedure, and familiarity with available devices.

Surgical retractors are well known in the surgical art, several examples being illustrated in U.S. Patents 4,617,916 issued to Le Vahn, et al, on October 21, 1986; and 4,27,421 issued to Symbas, et al, on December 9, 1986. For bypass surgery, the surgeon first makes an incision through the chest wall typically in the sternum

(stemotomy) or between adjacent ribs (thoracotomy). The surgeon then inserts the surgical retractor into the narrow opening created, and the ribs and tissues are spread apart through adjustment of the retractor, thus exposing the heart. Surgical retractors typically have a metal cross bar that spans the surgical opening created. The cross bars of most surgical retractors vary somewhat in size, but generally have rectangular cross-sections ranging from about 5mm (.19 in.) to 10mm (.38 in.) thick by about

19mm (.75 in.) to 38mm (1.59 in.) wide. These cross bars are convenient and stable mounting locations for a heart stabilization device.

During the bypass procedure, it is usually necessary to relocate the stabilization device on the heart, to adjust its orientation to improve visualization and/or access to the heart, to remove it completely from the surgeon's operating field, or to later reintroduce the stabilizer for application to the heart. Numerous adjustments of the stabilization device is especially characteristic of multiple bypass procedures. Obviously, it is critical that each adjustment be easy and fast, in order to minimize distraction to the surgeon. In addition, the connections of the stabilization device to the surgical retractor must be robust so that there is minimal movement of the stabilization device where it contacts the heart.

U.S. Patent 5,865,730 issued to Fox et al on February 2, 1999, discloses a stabilization device that may be attached to a wide variety of commerically available surgical retractors. In Fox et al, an operator quickly attaches the stabilization device to a surgical retractor, and adjusts its position and orientation with respect to the heart by operating simple mechanisms on a retractor mount. Surgeons have indicated a preference, however, for a similar type of stabilization device having more robust connections in order to further diminish movement of the portion of the heart stabilized.

What is needed, therefore, is an improved stabilization device that may be used with conventional, reuseable surgical retractors of various types, and which may be robustly attached to such surgical retractors quickly and easily.

SUMMARY OF THE INVENTION

In accordance with the present invention there is provided a device for stabilizing moving tissue, such as a beating heart, so as to facilitate surgical procedures on such tissue. In one embodiment of the present invention, a stabilizer is provided having a retractor mount for the releaseable attachment of the stabilizer to a surgical retractor. The stabilizer further comprises an elongated stem releaseably attached to the retractor mount, and at least one stabilizing foot on the distal end of the stem for engagement with the moving tissue. The retractor mount comprises a locking ring, a flange bushing, and a means for adjustably attaching the locking ring to the flange bushing. The retractor mount further comprises a compressible ball having a bore therethrough for receiving the stem. The compressible ball is held between the locking ring and flange bushing, so that when an operator tightens the locking ring onto the llange bushing, the diameter of the bore through the compressible ball is reduced, thereby causing the compressible ball to releaseably clamp upon the stem.

The retractor mount further comprises a base, a frame, and an attachment means for releaseably attaching the retractor mount to a surgical retractor positioned between the base and the frame, whereby the base is always approximately parallel to the frame for ail thicknesses of surgical retractors held between the base and the frame.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other aspects of the present invention will best be appreciated with reference to the detailed description of the invention in conjunction with the accompanying drawings, wherein:

Figure 1 is a isometric view of a first embodiment of a stabilizer attached to a surgical retractor (partially shown) to immobilize a portion of a heart.

Figure 2 is an isometric view of the retractor mount shown in Figure 1.

Figure 3 is an exploded, isometric view of the components of the retractor mount shown in Figure 2.

Figure 4 is a side view of the retractor mount shown in Figure 2.

Figures 5 is a side, cross-sectional view of the retractor mount shown in Figure 2, positioned but not clamped onto a surgical retractor.

Figure 6 is a side, cross-sectional view of the retractor mount shown in Figure

2, clamped onto a surgical retractor. Figure 7 is an enlarged, cross-sectional view of the retractor mount shown in

Figure 5.

Figures 8 is a top view of the retractor mount shown in Figure 2, in a first adjustment position.

Figure 9 is a top view of the retractor mount shown in Figure 2, in a second adjustment position.

Figure 10 is an isometric view of the stabilizer shown in Figure 1, with the retractor mount removed.

Figure 11 is a cross-sectional view of the distal portion of the stabilizer depicted in Figure 10.

Figure 12 is an isometric, bottom view of the distal portion of the stabilizer depicted in Figure 1.

Figure 13 is a second embodiment of the present invention attached to a surgical retractor (partial view).

Figure 14 is a cross-sectional view of the second embodiment of the present invention shown in Figure 13.

Figure 15 is an isometric view of a third embodiment of the present invention.

Figure 16 is a cross-sectional view of the third embodiment of the present invention shown in Figure 15.

Figure 17 is an isometric view of the distal portion of a fourth embodiment of the present invention used with a surgical, grasping device on the heart. Figure 18 is an isometric view of the distal portion of a fifth embodiment of the present invention used with a surgical retractor, with a stem of the stabilizer inserted into the body through a secondary opening spaced apart from a primary opening of the body.

Figure 19 is a sixth embodiment of the present invention, shown without a distal foot attached.

Figure 20 is an exploded view of the sixth embodiment of the stabilizer shown in Figure 19.

Figure 21 is a cross-sectional view of the sixth embodiment of the stabilizer shown in Figure 19.

Figure 22 is an exploded view of a segmented shaft of the sixth embodiment of the stabilizer shown in Figure 19.

Figure 23 is a cross-sectional view of a portion of the segmented shaft of the sixth embodiment of the stabilizer shown in Figure 19.

Figure 24 is an isometric view of the retractor mount of a seventh embodiment of the present invention.

Figure 25 is an exploded view of the retractor mount shown in Figure 24.

Figure 26 is a side sectional view of the retractor mount shown in Figure 25, shown with the retractor mount positioned but not clamped onto a thin retractor.

Figure 27 is a side sectional view of the retractor mount shown in Figure 25, shown with the retractor mount clamped onto a thin retractor. Figure 28 is a side sectional view of the retractor mount shown in Figure 25, shown with the retractor mount clamped onto a thick retractor.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 depicts a first embodiment of a stabilizer 1 and a retractor mount 20. The retractor mount 20 is shown attached to a surgical retractor cross bar 10 (partial view). A flexible hose 2 attaches the stabilizer to a suction source (not shown). The distal portion of the stabilizer is shown in contact with the organ 138 being stabilized and consisting of a left foot 69 and a right foot 68 which in some cases may be placed to straddle a vessel 137 to be operated on. The left and right feet, 69 and 68, are somewhat like clamshells in that they are generally hollow and crescent shaped. When the organ is in complete contact with the edge along the entire perimeter of each foot, and when a suction source is communicated to each foot via air passages through the stabilizer 1, the feet, 69 and 68, maintain enhanced attachment to the organ. How much force would be required to pull the stabilizer 1 away from the organ would depend on the seal created and the negative pressure of the suction. A significant amount of stabilization of the organ would also be achieved without the suction source, however, due to how well the organ conforms to the stabilizer, which is held firmly in the retractor mount 20. Again in Figure 1, it can be seen that the stabilizer 1 is attached to the retractor mount 20 which, in turn, is removably attached to the retractor cross bar 10. Also shown is distal ball 70 which allows angular and rotational movement of the distal portion of the stabilizer with respect to the lower stem 65, and a proximal ball 66 which allows rotational, angular, and longitudinal movement of the stabilizer 1 with respect to the retractor mount. As a result, it is possible to accommodate large variations in the position of the organ relative to the surgical retractor cross bar 10 location and orientation. This is important due to the wide range of surgical patient sizes, differences in anatomy, and variations in surgical technique. Turning to Figures 2 and 3, the retractor mount 20 has six main components: the mount base 24, the mount top 22, the cam lever 23, the ball clamp arm 21, the upper gripping pad 26, and the lower gripping pad 25. These components may be made of metal such as a stainless steel in order to be reusable and sterilizable in a steam autoclave, but preferably, components 21, 22, 23, and 24 are made of a rigid, medical grade plastic. The gripping pads 25, 26 are made of a less rigid, medical grade plastic. The cam lever 23 is hinged to base 24 by first pin 50 through holes 40 and 39. Mount top 22 is hinged to the base 24 by second pin 51 through holes 42 and 52. Ball clamp arm 21 is pivotally attached to mount top 22 by an integral, spring post 53 on the mating surface of ball clamp arm 21 into hole 31 of the mount top 22. Gripping pad 25 is retained in base 24 by an undercut recess 54 in base 24. Gripping pad 26 is retained in mount top 28 by a similar means.

It is often necessary during the surgical procedure to reposition the stabilizer, and this may easily be accomplished in this invention by using the two adjustment features of the stabilizer mount 20. Referring now to Figures 4, 5, and 6, the adjustment method is described for attachment of the retractor mount 20 to the retractor cross bar 10. Figure 4 shows the front view of the retractor mount 20 while the cam lever 23 is in the open position and before the retractor mount 20 is placed onto the cross bar 10. In Figure 5, a longitudinal cross-section through the components except for the cam lever 23 depicts positioning of the retractor mount 20 on the cross bar 10. This view also reveals how finger 37 locates into detent recess 48 in order to hold the cam lever 23 in the open position. In this position, the mount top 22 is essentially parallel to the base 24, thus creating clearance between the gripping pads 25, 26 and the retractor cross bar 10. In Figure 6, the cam lever 23 is shown in the closed position, which is accomplished by the user squeezing lever pad 36 and base 24 together. When the cam lever beam 46 abuts base 24, cam surface 38 will have pivoted to a locking position against the underside of the mount top 22. This causes mount top 22 to have pivoted about second pin 51 so that gripping pads, 25 and 26, are compressed against cross bar 10. This separating force acting between the base 24 and the mount top 22 at the cross bar 10 causes the cam lever 23 to remain in the locked position so that the retractor mount cannot move about on the cross bar 10. To unlock the retractor mount 20 from the cross bar 10, an upward force may be applied by the user to the cam lever pad 36 until cam surface 38 has pivoted sufficiently to reverse the rotational moment on the cam lever 23, causing it to then pop open. During the clamping process described, the spherical clamping surface 27 of the cam lever 23 and the spherical clamping surface 28 of mount top 22 are extended beyond the edge of base 24 so that clearance is allowed for assembly of stabilizer 1 to the retractor mount 20. These spherical clamping surfaces 27, 28 are aligned in order to hold firmly onto proximal ball 66 of the stabilizer 1.

Figure 7 shows an enlarged, cross-sectional view of the portion of the retractor mount 20 as it was depicted in Figure 5. This view shows more clearly than in Figure 5 the spring post 53 as it is snapped into hole 31 and partially projecting into hole 32 of gripping pad 26.

Turning now to Figures 8 and 9, the top view of retractor mount 20 is shown for two positions of the ball clamp arm 21, which has ratchet pawl 35 shown in engagement with ratchet teeth 34 on mount top 22. The spherical clamping surfaces 27 and 28 are seen in the open or loose position to allow movement of proximal ball 66 (Figure 1) within. When the user squeezes ball clamp arm 21 together with mount top 22, the ball clamp arm 21 pivots about spring post 53, and the clearance betweefi spherical surfaces 27, 28 is reduced, thus holding proximal ball 66 firmly. The leaf spring 33 on the mount top 22 exerts an opening force against the ball clamp arm 21. When ratchet pawl 35 is pulled away from ratchet teeth 34 by the user, the ball clamp arm 21 releases the ball 66, allowing movement of the stabilizer 1 while still captured in the retractor mount 20.

Figure 10 shows the first embodiment of the stabilizer 1, which was depicted in Figure 1. Stabilizer 1 includes a tube 60 having a proximal end 61, a distal end 62 and a lumen extending therebetween (not shown). Tube 60 is connected to a suction source by tube 2 so as to draw air from the distal end 62 to the proximal end 61. Tube 60 can include a number of stems, which are detachable from each other.

Figure 10 shows tube 60 as having a first upper stem 63, a second upper stem 64 and a lower stem 65. Stem 63 has been detached from the second upper stem 64 and moved proximally on flexible hose 2. Stem 63 and 64 can be connected to each other by a threaded engagement, a frictional push fit engagement or any other means well known to those of ordinary skill in the art. Figure 10 shows an external screw thread 93 on the distal end of the first upper stem 63, which would be attached to an internal thread on the proximal end of the second upper stem 64. The user would detach the two by rotating the first upper stem 63 while holding the second upper stem 64.

This feature allows portions of the tube 60 to be removed from the surgeons working area causing less obstruction during the procedure. The lumens through the upper stems 63, 64 are large enough to slide freely over the flexible hose 2, which is attached to the lower stem 65, and put out of the way. Second upper stem 64 can be detached from lower stem 65 in a similar manner, and moved proximally. The number of such stems may vary, depending on the desired length of the original assembly, the means of attachment to one another, and the ease of handling the individual components during a surgical procedure. Detaching these would typically be done after the adjustments on the retractor mount 20 have been made and the stabilizer feet 68, 69 are located properly on the organ. As mentioned above, this ability to detach the upper stems 63, 64 is advantageous in allowing improved access and visibility to the surgical site for the surgeon. By keeping the upper stems 63, 64 captured on the flexible hose 2, it is easy for the users (scrub nurse, etc,) to keep track of the components. The user may also easily reassemble the upper stems, 63 and 64, to the stabilizer 1 during the procedure if it is determined that the overall length of the stabilizer 1 is too short.

As described earlier, the proximal ball 66 may slide freely over stems 63, 64,

65 until the ball clamp arm 21 is locked in the closed position. This is because the proximal ball 66 is made of a material, preferably plastic, which is flexible enough to be compressed onto the stems 63, 64, 65. The hole through it, however, is just large enough to allow the ball 66, when not compressed, to move freely on the stems 63,

64, and 65. All the components of the stabilizer 1 shown in FIG. 10 may be made of metal such as stainless steel, except the flexible tube which is made of a medical grade, tubing material such as silicone or polyurethane. The preferred material for the feet 68, 69 and the bridge 75, all of which may be injected molded as one piece, is a plastic such as polycarbonate or polyethylene. This is true also for the manifold 67 and the stems 65, 64, 63. The distal end of the lower stem 65 has an integrally molded, distal ball 70 which fits tightly into a spherical cup or socket 71 feature of the manifold 67. This joint is tight enough to maintain its seal of the air passage through it and the orientation of the stabilizer 1 during the surgical procedure, yet loose enough to be adjusted easily by manipulation by the user.

Figure 11 is a cross-section of the distal portion of the stabilizer 1 shown in Figure 10. As seen from the figure, device 1 includes at least one, and preferably a pair of feet 68 and 69, attached to the distal end 62 of tube 60. Each foot extends outwardly from tube 60. Feet 68 and 69, respectively have proximal surfaces, 151 and 161, and distal surfaces, 152 and 162. Distal surfaces, 152 and 162, make contact, direct or indirect, with the organ when in use with the vacuum. As shown in the figure surfaces 152 and 162 are in contact with an organ 138 having a vessel 137 located midway between the left and right feet 68, 69. The air passages through it can be seen as well as the left and right foot filters 73, 72 on distal surfaces 152 and 162, which are snapped into grooves in the left and right feet 69, 68 respectively. Filters 72 and 73 help prevent particulate materials from entering tube 60 and causing a failure of the device.

Figure 12 is an isometric view of the distal portion of the stabilizer 1 of Figure 1, giving another view of the right and left foot filters 72, 73 assembled into the feet 68, 69. The foot filters 72, 73 can be a mesh type of structure and may be a metal such as stainless steel or a plastic such as polycarbonate. They contain a plurality of holes sized largely enough and spaced in a manner to allow suction of the air from within the space between the organ surface and each screen, yet small enough to prevent tissue from blockir g the suction passage through the left and right feet 68,69.

Figures 11 and 12 also show how the left and right feet 69, 68 have outer perimeter edges 74 and 76, that together can seal upon an essentially convex surface such as on the heart. For the enhanced attachment of the left and right feet 68, 69 to the organ surface by means of the evacuation of air and fluids from within, it is preferred that the feet perimeter edges 74, 76 remain in contact with the organ as it moves or is being manipulated. The embodiment shown in Figure 11 has the feet perimeter edges 74, 76 defining a partial, spherical surface, that is they have a spherical profile, which has a radius of about the size of an orange, but this concavity may also vary in its depth and configuration. Another advantage of this embodiment is that the surface of the tissue in the span between the left and right feet 68, 69 is tensioned slightly, thus further stabilizing the vessel 137 or other tissue of interest to the surgeon.

Skipping briefly to Figure 16, there is a third embodiment of the distal portion of the present invention. Separate components for holding tissue away from the suction orifices 133, 134 have been eliminated by the addition of a plurality of pegs extending outwardly from the proximal surface of the feet 130 and 131. The pegs 132 are preferably cylindrical and parallel to one another as shown in this embodiment, but may vary in size, spacing, and orientation. The tips extend to a length slightly proximal to the imaginary, concave surface described and provide atraumatic contact with the organ as it is pulled into the feet 130, 131 by the suction force. The surface of the organ 138 may tent into the interstitial spaces between the projections 132, thus adding the benefit of increased resistance to sliding of the stabilizer feet 130, 131 in the side-to-side directions. The projections 132 are spaced sufficiently distant from perimeter edges 74, 76 to allow the organ surface to seal properly against the left and right feet 69, 68. In addition, the pegs create a tortuous path for any particulate and therefore also act as a filter. Now going back to Figure 13, there is an isometric view of a second embodiment of the stabilizer. The primary difference of the second embodiment from the first embodiment shown in Figure 1 is the increased, positional flexibility, due to gooseneck 80 comprising a plurality of ball/socket elements 82. A retractor mount 86 clamps onto the retractor crossbar 10 as before using cam lever 88, but the mount differs in that it has a draw latch 87 for tensioning/releasing cable 81 for locking unlocking the hold for the orientation of the gooseneck 80. Figure 14 further depicts this embodiment, showing the air passages within and the interactions of the components as the retractor mount is clamped onto crossbar 10 and the gooseneck 80 is locked into orientation. The distal end of cable 85 is terminated with swaged fitting 85, which abuts against an internal retention feature 97 of the manifold 98. Tension in cable 81 is created when draw latch 87 is squeezed against base 89, pivoting about draw latch pivot 90, causing draw latch hook 92 to swing over center of pivot 90. Reversal of this process releases the tension and allows the surgeon to reposition the gooseneck 80. In this embodiment, flexible hose 2 is attached to mount top 91. The number and size of ball/socket elements may vary and may be made of metal or plastic.

Referring to Figure 15, the third embodiment referred to earlier in Figure 16 is shown in isometric view. A remote actuator 101 has been provided for locking the ball joint 109 on the distal end of the shaft 104. The surgeon can release the tightness of the ball joint 109 by squeezing together remote actuator 101 and shaft proximal end 102. Upon release, the ball joint 109 is tight again and the stabilizer maintains its orientation. Referring again to Figure 16, there is shown a cross- sectional view of the embodiment depicted in Figure 15, also showing the air passage through it. The locking force is provided by coil spring 110 pushing on shaft flange

79. The stabilizer orientation is maintained by the frictional forces between components 105, 106, and 108 which are the shaft cup, manifold cup, and bell flange

108 on the distal end of shaft 107. A proximal ball 66 slides and rotates freely on shaft 104 in a similar manner as described in the preferred embodiment in Figure 1.

The retractor mount used for this embodiment would be the same as the one described in the preferred embodiment of Figure 1. Flexible hose 2 attaches to remote actuator 101. Providing an actuator for ball and socket joint 109, which is remote or proximal to the joint 109 is advantageous for the surgeon. The surgeon's hands do not need to be placed close to organ being operated on, which could risk accidental contact and would obstruct the view.

Figure 17 is an isometric view of the distal portion of a fourth embodiment of a stabilizer, being used in combination with a second, surgical grasping instrument 124 for heart stabilization. In this embodiment, left and right flanges 123 and 120 have been added to the left and right feet 121, 122. Flanges 123 and 120 extend from proximal to the proximal surface 181 and 182 of the feet. The flanges provide a means of repositioning the distal portion of the stabilizer on the heart. Using the grasping instrument 124 allows for enhanced access and visibility to the surgical site, and aids in the precise positioning of the stabilizer feet. This is especially advantageous when operating through a narrow incision in the chest wall such as a mini-thoracotomy.

To further assist in the stabilization of the heart or other organ, other access retractors may also be used in conjunction with the present invention, such as spoon shaped probes to move other tissue from the surgical site.

A fifth embodiment of the stabilizer is depicted in Figure 18. In this embodiment, the stem assembly 150 (also referred to as a stem) is detachable from the stabilizer foot assembly 144. The stem 150 may be introduced into the body and to the wound site through a separate, smaller incision 140 (also referred to as a second opening) adjacent to the main incision 142 (also referred to as a first opening). Once inserted, the stem 150 is attached to stabilizer foot assembly 144 by means of a pair of cup-shaped graspers 148 clamping onto ball joint 146 or by various other means which allow angular variation of the stem 150 with respect to the stabilizer foot assembly 144. The graspers 148 and the ball joint 146 are also referred to as a connector. The graspers 148 may be remotely actuated to open or close by a mechanism on the proximal portion of the stem assembly by various means also, such as is commonly used for endoscopic graspers and needle holders. It can be seen in Figure 18 that the stabilizing foot assembly 144 is attached directly to a flexible, suction hose to enhance the attachment of the foot assembly 144 to the organ. The stem 150 may be hand held by the surgeon's assistant in order to stabilize the organ during the surgical procedure. It may also be held by a supporting mount or structure attached to the side of the surgical table, such mounts being well-known in the surgical art. It may also be used in combination with a trocar cannula with or without screw threads to attach to the body wall, or with other kinds of trocars well known in the art. U.S. Patent 5,215,526 issued to Deniega, et al, on June 1, 1993, describes a trocar, which may be used in this surgical method. The advantage of using a trocar cannula to receive the stabilizing stem is that it provides an access port to the inside of the body while protecting the tissue from trauma associated with manipulating the stem through the port.

The proximal portion of stem 150 may also be removably attached to the retractor 12 or other relatively stationary structures by means of various fixation devices which could easily be devised by those skilled in the art. The principal advantage of the fifth embodiment shown in Figure 18 is that the access to and visibility of the surgical site on the stabilized organ is improved because of the absence of the stem assembly 150 in the primary incision (or first opening) 142.

A scalpel or a trocar may make the smaller incision 140. Then the stem 150 may be inserted. A novel variation of the present invention is to eliminate the step for creating the second incision 140 before insertion of the stem 150 by using a stem having a sharpened distal end. The stem could then be used to pierce through the tissue wall near the primary incision, care being taken to insure that the underlying organs are protected from the sharp tip of the stem as it enters the body cavity. This is easily accomplished since the larger primary incision has already been made, and the surgeon can reach inside to feel the piercing stem protruding through the tissue wall and controllably guide its entry into the body cavity. Then the distal end of the stem could be attached to t le foot by a specially adapted coupling. For example, the distal end of the stem may have a threaded portion immediately proximal to a tapered point. This threaded portion could then be screwed into a threaded hole on the specially adapted coupling on the foot.

A further variation of the present invention is the incorporation of more than one stem for stabilizing the foot in order to increase the stability achievable for the particularly organ to which the device is applied. The combined use of multiple stems provides a sort of truss work to increase the rigidity of the stabilizing system. Each stem would be placed through the body wall percutaneously and at spaced- apart locations near the primary incision, and then the distal ends of the stems could be releaseably attached to the foot. Obviously, the increase in the number of stems attached must be matched by an increase in the number of attachment points on the foot. This can be accomplished by having multiple ball joint connections on the upper surface of the foot, as may be easily incorporated into the design shown in Figure 17 by those skilled in the art. Or it may be accomplished by having a plurality of threaded holes in the foot coupling which has been specially adapted to receive stems having threaded and sharpened ends as previously described.

A sixth embodiment of a stabilizer 200 is depicted in Figures 19-23. The stabilizer 200 has features, which will be described next, for improved stabilization of a bodily organ, while maintaining the ease of adjusting the stabilizer to the anatomy of the surgical patient.

Referring now to Figure 19, the stabilizer 200 comprises a retractor mount

201 and a stem 203. A foot on the distal ball 284 of the stem 203 is not shown, but may be pivotally attached to the distal ball 284 as in the prior embodiments for contacting the surface of the bodily organ. An operator may attach the retractor mount 201 onto a surgical retractor such as described for the previous embodiments. A cam lever 252 is actuated in the downward direction to lock the retractor mount 201 onto a retractor (not shown) and is actuated in the upward direction to release the retractor mount 201 from a retractor. The stem 203 comprises a hollow, proximal stem segment 294, a distal stem segment 280, and a flexible tube 299. The proximal and distal stem segments, 294 and 280, are releaseably attached together in order to provide the operator with the option to use the stem 203 in either a long version or a short version, depending on the reach needed to stabilize the bodily organ. The stem 203 is releasably attached to a compressible ball 208 of the retractor mount 201 by the actuation of a locking lever 206 of a locking ring 202. When the locking lever 206 is moved in the clockwise direction as viewed from the top, the retractor mount 201 becomes rigidly attached to the stem 203. When the locking lever 206 is released, that is, it is moved in the counter-clockwise direction, the stem 203 may slide longitudinally with respect to the ball 208. When released, the stem 203 also may pivot in a wide, conical range of motion about the center of the ball 208.

Figure 20 is an exploded view of the stabilizer 200. The proximal stem segment 294 is shown detached from the distal stem segment 280. The distal ball 284 is fixedly attached to a distal fitting 282 of the distal segment 280 during assembly by using an adhesive or press fitting the pieces together. The distal ball 284, the distal stem segment 280, and the proximal stem segment 294 are preferably made from a stainless steel, but may also be made from a rigid, medical grade plastic.

Still referring to Figure 20, the retractor mount 201 comprises a base 260, and a frame 220, each retaining a compliant, gripping pad 240 for clamping onto a retractor in a similar manner as described for Figure 6. The cam lever 252 is pivotally attached to the base 260 by a cam lever pin 270 through a lever hole 254 of the cam lever 252 and through first and second base holes, 262 and 263, of the base 260. The frame 220 is pivotally attached to the base 260 by a frame pin 272 through a frame pivot hole 228 of the frame 220 and third and fourth base holes, 264 and 265, of the base 260. The cam action of the cam lever 252 for clamping the retractor mount 201 onto a retractor is the same as described for the retractor mount 20 shown in Figures 4-6. The base 260, the frame 220, and the cam lever 252 are preferably made from a rigid, medical grade plastic. The cam lever and frame pins, 270 and 272, are made preferably from stainless steel. The two gripping pads 240, also called first and second gripping pads, are made from an elastic material such as polyurethane or neoprene rubber. The portion of retractor mount 201 for clamping onto the surgical retractor is also referred to as a second locking means and comprises cam lever 252, frame 220, and base 260.

Still referring to Figure 20, a retaining plate 230 is fixedly attached to frame 220 by three lugs 224 through three frame holes 226 of the frame 220. The lugs 224 press into three lugholes 231. The retaining plate 230 is preferably made of stainless steel, as are the lugs 224, and has a circular opening 232 for retaining a flanged bushing 214. Flanged bushing 214 has a bushing bore 218 through it having a diameter slightly smaller than the diameter of the ball 208. Likewise, locking ring 202 has an internal thread 204 through it having a minor diameter significantly smaller than the diameter of the ball 208, but larger than the largest diameter of the stem 203. The ball 208 is retained between the locking ring 202 and the flanged bushing 214. The locking ring 202 is provided with internal thread 204 to screw onto an external thread 216 of the flanged bushing 214. When the locking ring 202 is rotated in a tightening direction onto the flanged bushing 214, the ball 208 is compressed therebetween. Because the ball 208 has a plurality of splits 210, compression of the ball 208 reduces the diameter of a ball bore 212 through the ball 208, thus tightening the ball 208 onto the stem 203. When the locking ring 202 is rotated in a loosening direction, the ball 208 loosens on stem 203. A lock lever stop 222 is provided on the frame 220 to prevent the locking ring 202 from being removed from the flanged bushing 214 once assembled.

For the stabilizer 200, the forces applied to the ball 208 when compressed between the locking ring 202 and the flanged bushing 214 are approximately in a direction tangential to the surface of the ball 208 and are evenly distributed about the equator of the ball. This force application is different than for the retractor mount 20 described for Figures 1-9. Retractor mount 20 instead applies forces normal to the ball 66 (see Figure 1) and on opposing sides rather than evenly about the equator.

The retractor mount 201 of the stabilizer 200 of the sixth embodiment of Figures 19-

21 provides a more stable attachment to the stem 203 than does the retractor mount

20 of Figures 1-9. This is because of the "wedging" action provided by the locking ring 202 and the flanged bushing 214 onto the ball 208 and the very high forces that may be generated by the incorporation of screw threads 288 and 289. The portion of retractor mount 201 for attachment to stem 203 is also referred to as a first locking means and comprises locking ring 202 and bushing 218.

Figure 21 is a cross-sectional view of the stabilizer 200 for when the retractor mount 201 is actuated to mount onto a retractor (not shown). This view shows how the cam lever 252 causes the base 260 to pivot with respect to the frame 220. Also shown is an external thread 288 of the distal stem segment 280 for the releaseable attachment to the proximal stem segment 294. This view also shows a flexible tube 299 passing through a proximal stem bore 296 (see Figure 22) of the hollow proximal segment 294 and attaching over a wide tip 292 on the proximal end of the distal stem segment 280. As described for the flexible tube 2 of the embodiment of Figure 10, the flexible tube 299 of Figure 21 serves to retain the hollow proximal stem segment 294 when it is detached from the distal stem segment 280. Similar to the embodiment of Figure 10, in some situations a shortened version of the stem 203 is all that is needed once the stabilizer 200 is adjusted into place on the surgical patient. The embodiment of Figure 21 allows the user to detach the proximal stem segment 294, thus providing improved access and visibility to the surgical site. By retaining the proximal stem segment 294 on the flexible tube 299, it is easy for the user to find and reattach the proximal stem segment 294 onto the distal stem segment 280, should the longer version of the stem 203 be needed later during the surgical procedure. The proximal end of the flexible tube 299 may also be attached to a vacuum source as described for the embodiment of Figure 10, so that a vacuum may be supplied to the foot (not shown) attached to the distal ball 284 of the stabilizer 200 in Figure 21. The stabilizer 200 may be used both with and without a vacuum, and yet still be effective for stabilizing tissue such as a beating heart. Figure 22 is an ex{ loded view of the stem 203. The distal stem segment 280 has a shank 286 with a reduced diameter for location into a shank opening 297 of the proximal stem segment 294. Distal stem segment also has a plurality of external threads 288 for screwing into a plurality of internal threads 289 of the proximal stem segment. The number of external threads 288 may vary, but is preferably between one to six. Proximal to the external threads 288 is a cylindrical projection 290, which is coaxial with the shank 286 and the longitudinal axis of the stem 203. Cylindrical projection 290 has a wide tip 292, which has a shape particularly suited for retaining flexible tube 299 pulled over it. Other shapes for this widened tip 292 are possible while retaining the intended function. When assembled, the flexible tube 299 is passed through the bore 296 of the proximal stem segment 294 and then attached to the projection 290 of the distal stem segment 280.

Figure 23 shows the assembled stem 203 in cross-section to reveal how the tube 299 serves to help hold together the proximal and distal stem segments, 294 and 280. The portion of the tube 299 over the wide tip 292 is compressed within the bore 296 of the proximal stem segment 294. The stem segments, 294 and 280, as a consequence, are less likely to come apart due to the friction created by this compression, even if the operator did not fully tighten the external thread 288 into the internal thread 289.

Figures 24-28 illustrate a further embodiment of the retractor mount shown in Figure 19. Figure 24 is an isometric view of a retractor mount 300, shown without compressible ball 208 and stem 203 (see Figure 19). Even though the compressible ball 208 is considered part of the retractor mount 300, it is not shown in Figures 24- 28 for clarity and since it is identical to the earlier embodiment shown in Figures 19- 21. A locking lever 306, a locking ring 302 and a flanged bushing 314 are also physically and functionally identical to the corresponding parts of the embodiment shown in Figures 19-21. The retractor mount 300 of Figure 24 further comprises a cam lever 352, a link 390, a base 360, a frame 320, a first pin 380, a second pin, 382, a third pin 372, and a fourth pin 370. Turning now to Figure 25, the retractor mount 300 is shown in an exploded view. Base 360 attaches to frame 320 by link 390, so that base 360 may swing towards and away from frame 320. One end of link 390 fits moveably into a base recess 361 and is connected to base 360 by first pin 380 inserted rotatably into a first base hole 363 and a second base hole 365, and inserted tightly into a first link hole 394. The opposite end of link 390 fits moveably into a frame recess 323 and is connected to frame 320 by a second pin 382 inserted rotatably into a fifth frame hole 321 and a sixth frame hole 322, and inserted tightly into a second link hole 392. A first post 362 of base 360 moves freely in an arcuate slot 328 of first frame wing 330, and a second post 364 moves freely in an arcuate slot 329 of second frame wing 331.

Still referring to Figure 25, a pawl 340 is pivotally mounted between a first frame wing 330 and a second frame wing 331 by third pin 372 inserted rotatably into a first frame hole 324 and a third frame hole 326, and inserted tightly into a pawl hole

342. A plurality of pawl teeth 367 operationally engages with a plurality of base teeth 366 of base 360.

Still referring to Figure 25, cam lever 352 is pivotally attached to frame 320 by fourth pin 370 inserted rotatably into a second frame hole 325 and a fourth frame hole 327, and inserted loosely into a lever axle bore 354 of a lever axle 353 of cam lever 352. A cam surface 355 positioned centrally on lever axle 353 operationally engages with a pawl surface 341.

Figure 26 is a side view of retractor mount 300 with a portion shown in cross-section, and for when the retractor mount 300 is clamped onto a thin retractor 400. Thin retractor 400 may be similar to surgical retractor 10 of Figure 1, and as earlier described, is commonly used by surgeons for spreading apart an incision made in the surgical patient. In this view, the cam lever 352 is shown in an up position so that force from cam 355 is released from pawl surface 341, thus allowing pawl teeth 367 to disengage from base teeth 366. As shown in this view, base 360 is free to move towards and away from frame 320 so that retractor mount 300 may be positioned onto thin retractor 400. Base 360 is always approximately parallel to frame 320, no matter how closely it is positioned with respect to frame 320.

Projections 332 are provided for improving the stability of the retractor mount once clamped onto thin retractor 400.

Figure 27 is the same side view of the retractor mount 300 as is shown in Figure 26. In Figure 27, however, the cam lever 352 is shown in the locked position in order to attach rigidly the retractor mount 300 to the thin retractor 400. The cam surface 355 of the cam lever 352 is shown applying a downward force onto the pawl surface 341, thus operationally engaging the pawl teeth 367 with the base teeth 366. This engagement prevents the pawl 340 from slipping on the base 360 once the cam lever 352 is in the locked position. When the user initially pushes down the cam lever 352, the pawl 340 swings about third pin 372 and drives the base 360 to the left and towards the frame 320. When the base 360 contacts the bottom of the thin retractor 400, the base 360 no longer moves to the left. The base 360 instead rocks slightly about first pin 380, due to the width of arcuate slots, 328 and 329, being greater than the diameter of first and second posts, 362 and 364. Therefore, the final downward movement of the cam lever 352 causes the base 360 to tighten against the bottom of thin retractor 400, thus increasing the holding force of the retractor mount 300 onto the thin retractor 400. Cam surface 355 is shaped such that when the cam lever 352 is fully actuated to the locking position, the cam lever 352 becomes locked in an "over center" position onto the pawl surface 341. The user applying an upward force to the cam lever 352 is required to unlock the cam lever 352, so that the retractor mount may be removed from the thin retractor 400.

Figure 28 is the same view of the retractor mount 300 as in Figures 26 and

27. In Figure 28, however, the retractor mount 300 is shown clamped onto a thick retractor 401. The base 360 is still approximately parallel to the frame 320, but the link 390 is more vertical than in Figure 27. Also, the first and second posts, 362 and

364, are more justified to the opposite end of the arcuate slots, 328 and 329 respectively. But the retractor mount 300 is locked onto the thick retractor 401 and can only be released by the user applying an upward force to the cam lever 352. A comparison of Figures 27 and 28 demonstrates one advantage of this embodiment of the retractor mount 300. That is, the retractor mount 300 may be clamped onto surgical retractors having a wider variation in thickness than was possible using the retractor mounts of the previous embodiments shown in Figures 1 and 19. The earlier embodiments shown in Figures 1 and 19 have a V-closure method onto the retractor; that is, the base of each does not maintain parallelism to the frame. The use of resilient gripping pads 240 such as shown in Figure 20 aids in distributing clamping force onto the retractor, but because of V-closure, the net force applied by the base 260 is not centered with the opposing reaction forces applied by the frame 220. This imbalance of applied and reaction forces results in a tendency for the retractor mount to slip on the retractor. So for the retractor mounts of Figures 1 and 19, the greater the thickness of the retractor used, the greater the tendency for the retractor mount to slip on the retractor. The embodiment shown in Figures 24-28, however, maintains a balance of the applied and reaction forces, due to the parallel closure of the base 360 to the frame 320. Using this type of retractor mount provides the surgeon with a greater number of choices of surgical retractors that may be used with the stabilizer.

All of the embodiments for a stabilizer described herein may be used effectively for stabilizing moving tissue without supplying a vacuum to the distal foot. When the operator uses any of the embodiments to stabilize moving tissue mechanically, without vacuum, it is advantageous to place an absorbent pad such as cotton gauze between the distal foot and the moving tissue. The absorbent pad helps to prevent the distal foot from sliding on the surface of the moving tissue, and also minimizes trauma to the tissue surface.

As disclosed, the present invention relates to an apparatus for stabilizing tissue. The invention is preferably used to stabilize a beating heart during a coronary artery bypass graft procedure using a surgical retractor. The numerous embodiments of the stabilizer described herein can also be used on other bodily organs, such as stomach and lung. The stabilization device and its alternate embodiments, and the method of using them have been described in detail, but it should be understood that variations and modifications could be incorporated. These modifications may include substituting elements or components that have the same function to achieve the same result for those described herein.

SUMMARY OF THE INVENTION

The present invention is a device for stabilizing moving tissue such as the heart within the body of a surgical patient, such as during a coronary artery bypass graft surgical procedure. The device comprises a stem having proximal and distal ends, a compressible ball slideably attached onto the stem, and at least one foot connected to the distal end of the stem. Each foot extends laterally from the stem and has a distal surface for placement onto moving tissue. The device further comprises a retractor mount comprising a first locking means for operational engagement with the compressible ball on the stem for adjustably holding the stem in a desired orientation during the surgical procedure, and a second locking means for releaseably attaching the stem to the surgical retractor.

In a preferred embodiment of the present invention, the first locking means comprises a locking ring and a bushing attached to the retractor mount. The locking ring has a plurality of internal threads and the bushing has a plurality of external threads and a bore therethrough. The compressible ball sits in the bore of the bushing so that when the locking ring is screwed onto the bushing, the compressible ball is retained on the stem between the locking ring and the locking bushing. Rotation of the locking ring in a tightening direction causes the compressible ball to clamp onto the stem and maintain a fixed orientation of the stem in the retractor mount. Rotation of the locking ring in the loosening direction causes the compression ball to loosen from the stem so that orientation of the stem may be adjusted or the stem may be removed. In another preferred embodiment of the present invention, the second locking means comprises a cam lever, a frame, and a base. The frame and the base are positionable around the rectangular cross bar of the surgical retractor, whereby actuation of the cam lever in a tightening direction causes the base to move towards the frame and to lock into place, thereby clamping the retractor mount onto the surgical retractor. Actuation of the cam lever in a loosening direction causes the base to move away from the frame, thereby releasing the retractor mount from the surgical retractor.

Also in a preferred embodiment of the present invention, the retractor mount further comprises a first gripping pad attached to the base and a second gripping pad attached to the frame. The gripping pads are made from a flexible material and resiliently contact the cross bar of the surgical retractor when the second clamping means is clamped onto the surgical retractor. The gripping pads allow the retractor mount to be clamped onto surgical retractors having cross bars of varying thickness. In another preferred embodiment, actuation of the second locking means causes the base to move parallel to the frame throughout the range of motion of the base, further enabling the retractor mount to be clamped on surgical retractors having cross bars of varying thickness.

In another preferred embodiment of the present invention, the stem comprises a distal stem segment and at least one proximal stem segment, and the distal and proximal stem segments are detachably connected together end-to-end by a stem attachment means. In another preferred embodiment, a lumen extends between the distal and proximal ends of the stem. The device further comprises a flexible tube for fluidly connecting the proximal of the stem end to an external vacuum supply source, and the foot has a vacuum chamber fluidly connected to the lumen of the stem. Vacuum may be communicated to the interface between the distal surface of the foot and the tissue. In another variation of this embodiment, the flexible tube fluidly attaches directly to the distal stem segment, so that vacuum supply may still be communicated to the vacuum chamber of the foot when the stem segments are not attached by the stem attachment means.

Claims

WHAT IS CLAIMED IS:

1. A device for stabilizing moving tissue within a human body, said device comprising:

a) an elongated stem having proximal and distal ends;

b) a compressible ball slideably mouned onto said stem;

c) at least one foot connected to said distal end of said stem, each foot extending laterally from said stem and having a distal surface for placement on moving tissue; and

d) a retractor mount comprising a first locking means for operational engagement with said compressible ball on said stem for adjustably holding said stem in a desired orientation during a surgical procedure, and a second locking means for releaseably attaching said stem to said retractor mount.

2. The device according to Claim 1 wherein said first locking means comprises a locking ring and a bushing attached to said retractor mount, said locking ring having a plurality of internal threads, said bushing having a plurality of external threads and a bore therethrough, said compressible ball seated in said bore of said bushing, said locking ring screwed onto said bushing, thereby retaining said compressible ball on said stem between said locking ring and said locking bushing, whereby rotation of said locking ring in a first tightening direction causes said compressible ball to clamp onto said stem and maintain a fixed orientation of said stem in said retractor mount, and rotation of said locking ring in the opposite loosening direction causes said compression ball to loosen from said stem so that the orientation of said stem may be adjusted or said stem may be removed. The device according to Claim 2 wherein said locking ring compresses a locking lever exten ling therefrom for manual actuation in either the tightening or loosening directior..