Stabilizer tool for fully endoscopic coronary artery bypass grafting

Abstract

The reconfigurable tool carries a suction pod adapted for robotic surgery, and its distal end with the suction pod is insertable through a small port incised in a living body to access a workspace for performing cardiac repair. The tool has an articulating hub with a base and a slider, and the suction pod pivots from the slider. The base has a keyed surface configured to interlock with the keyed surface of the pod. A pull cord for retracting the suction pod toward the tool's support tube has a relaxed state that allows the first and second keyed surfaces to separate so that the suction pod can expand to grasp tissue to be stabilized in a desired position. The pull cord has a tensioned state in which the first and second keyed surfaces interlock with each other to prevent pivoting of the suction pod.

Description

[Technical Field]

[0001] The present invention relates generally to tools for cardiac / thoracic surgery, and more particularly to a stabilization tool for restraining / stabilizing coronary artery regions to allow anastomosis in or around a beating heart, adapted to pass through small incisions / tunnels of the type typically used in robotic surgery by allowing the tool parts to be reconfigured and / or assembled in situ.

[0002] The present invention is particularly useful for a coronary artery bypass procedure known as Off-Pump Coronary Artery Bypass Grafting (OPCABG). OPCABG has typically been performed using a transsternal procedure such as an open chest cavity, but robotic surgery, which can be performed through a small incision using a robotic arm, has become more common. [Background technology]

[0003] To avoid the need for open-chest surgery, which requires long incisions and cutting the sternum, the use of minimally invasive cardiac surgery (MICS) has become a leading method for performing cardiac repair. A working space for MICS is sometimes created within the thoracic cavity using one or more small incisions, sometimes by introducing CO2 gas to expand the thoracic cavity, and using a lift winch-type retractor (e.g., the Medtronic ThoraTrak™ retractor system, which uses a wire and winch mechanism to lift the chest from the outside) or (in the case of mitral valve repair) retractor blades that are lifted by a shaft through the chest wall (e.g., similar to the AtriCure Atrial Lift System).

[0004] One particular type of MICS is known as totally endoscopic coronary artery bypass (TECAB), which may be performed through four to five small slits (i.e., ports) for the insertion of several robotically controlled instruments and other support devices into the coronary artery area (see Figure 11). The da Vinci® Surgical System from Intuitive Surgical, Inc. is an example of a robotic system used for this type of closed-chest surgery. Summary of the Invention [Problem to be solved by the invention]

[0005] The robotic system includes a robotic arm operated by the surgeon. The robotic system may also include, for example, a camera, cutting tools, grasping tools, and suturing tools. It is preferable to perform surgery while the heart continues to beat, so that cardiopulmonary bypass is not necessary. When the heart is beating, it becomes desirable to restrain or stabilize the area around the heart. To achieve a high stabilization effect, stabilizer members with suction force may be preferred to adhere closely to the surface to be stabilized. Support members for tool members contacting the stabilized area must be capable of achieving a sufficiently small profile to be inserted into the desired location and must also be sufficiently rigid to suppress the pulsatile motion of the heart. Inserting stabilization tools with appropriate dimensions and suction capabilities through the small holes used in TECAB and other procedures has been extremely challenging. In particular, cardiac stabilizer tools used to stabilize the area for anastomosis must pass through small holes (e.g., approximately 12 mm) to be placed inside the body. Examples of prior art procedures and tools are shown in US Pat. Nos. 6,936,001 and 8,870,900, which are incorporated herein by reference. [Means for solving the problem]

[0006] The present invention achieves these objectives by providing a reconfigurable elongated tool carrying a suction retention mechanism that is compatible with robotic surgery and port surgery (e.g., small stoma surgery using manually inserted long-shaft tools).

[0007] In one aspect of the present invention, a stabilizer configured for use in minimally invasive cardiac surgery includes a support tube extending from a proximal end to a distal end, the distal end adapted to be inserted through an incision into a working space within a patient. An articulation hub is attached to the distal end of the support tube, the articulation hub having a proximal end that pivots about a first axis substantially transverse to the longitudinal axis of the support tube at the distal end of the support tube. A pair of suction arms are attached to the articulation hub at the distal end of the articulation hub, the suction arms configured to be attached to a vacuum pressure source. The suction arms are configured to adhere to (i.e., adhere to) a tissue surface of a patient upon application of vacuum pressure. The suction arms are configured to pivot within a common plane at the distal end of the articulation hub, and the suction arms have a first keyed surface at their proximal ends. A pull cord is coupled to the suction arms and extends through the support tube from the suction arms to the proximal end. The articulation hub is comprised of a base portion and a sliding portion, and the suction arms are attached to the sliding portion. The base portion has a second keyed surface configured to interdigitate with the first keyed surface. The pull cord has a relaxed state that allows the first and second keyed surfaces to separate so that the suction arms can spread to grasp tissue. The pull cord has a tensioned state in which the first and second keyed surfaces interdigitate so that pivoting of the suction arms is prevented. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing the placement of instruments in multiport cardiac surgery. [Figure 2] FIG. 2 is a perspective view of a first embodiment of a ballast tool in a closed configuration. [Figure 3] FIG. 3 is a proximal end view of the stabilizer tool of FIG. 2. [Figure 4]3 is a perspective view of the stabilizer tool of FIG. 2 showing the distal end in greater detail. [Figure 5] 3 is a perspective view of the ballast tool of FIG. 2 in an open configuration. [Figure 6] 3 is a perspective view of the distal end of the stabilizer tool of FIG. 2 in an open configuration. [Figure 7] 3 is a partial cross-sectional view of the ballast tool of FIG. 2 in an open configuration. [Figure 8] FIG. 3 is a side perspective view of the ballast tool of FIG. 2. [Figure 9] FIG. 3 is an end perspective view of the ballast tool of FIG. 2. [Figure 10] FIG. 3 is a cross-sectional exploded view of the ballast tool of FIG. 2. [Figure 11] FIG. 11 is an unexploded cross-sectional view corresponding to FIG. 10. [Figure 12] FIG. 3 is a perspective view of the articulation hub and support tube of the stabilizer tool of FIG. 2. [Figure 13] 3 is a perspective view of a portion of the receiving portion of the support tube of FIG. 2. FIG. [Figure 14] FIG. 10 is a perspective view of a second embodiment of a stabilizer tool having an additional axis of motion, the stabilizer tool in an open configuration. [Figure 15] FIG. 15 is a perspective view of the ballast tool of FIG. [Figure 16] FIG. 15 is an exploded view of the ballast tool of FIG. [Figure 17] FIG. 10 is a side view of a third embodiment of a ballast tool according to the present invention. [Figure 18] FIG. 18 is a perspective view of the proximal end of the stabilizer tool of FIG. 17. [Figure 19] FIG. 18 is a perspective view of the distal end of the stabilizer tool of FIG. [Figure 20] FIG. 18 is an exploded view of the distal end of the stabilizer tool of FIG. [Figure 21] FIG. 18 is a more detailed perspective view of the distal end of the stabilizer tool of FIG. 17. [Figure 22] 18 is a cross-sectional view of the distal end of the stabilizer tool of FIG. 17. [Figure 23] 18 shows a portion of the proximal end of the stabilizer tool of FIG. 17. [Figure 24] FIG. 18 is a partial exploded view of the proximal end of the stabilizer tool of FIG. [Figure 25] 18 is another exploded view of the proximal end of the stabilizer tool of FIG. 17. [Figure 26] 18 is a perspective view showing a portion of the mechanism at the proximal end of the stabilizer tool of FIG. 17 for adjusting the pull cord. FIG. [Figure 27] 18 is a partially exploded view showing a portion of the mechanism at the proximal end of the stabilizer tool of FIG. 17 for adjusting the drive belt. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1 shows a patient's body 10 with multiple instruments 11 inserted through different respective incision holes 12 (i.e., tunnels or ports) to access the interior working space. The present invention provides a stabilization tool that can be inserted as a single piece through each hole (e.g., through a side hole or side port on the outside of the patient's body).

[0010] A first embodiment of the present invention is shown in Figures 2-13. The stabilizer tool 15 has a closed configuration in Figures 2-4, with the support tube 16, articulating hub 17, suction arm 18, and suction arm 19 aligned in a straight line to easily pass through the incision hole. The support tube 16 extends from its proximal end to its distal end. The articulating hub 17 is attached to the distal end of the support tube. The proximal end of the hub 17 pivots about an axis substantially transverse to the support tube 16 at the distal end of the support tube 16. When in the closed configuration, the outer envelope of the tool body fits within the diameter of the incision hole (e.g., 12 mm), allowing the distal end of the tool and a support rod or shaft to be inserted through the hole and into the thoracic cavity. The proximal end of the tool is configured to be attached to a patient table or other fixed structure by an articulating arm (e.g., an articulating and / or telescoping stabilizer arm that can grasp, move, and secure the shaft in an optimal position).

[0011] The suction arms 18, 19 have suction pods at their distal ends and mounting pivots at their proximal ends. Suction tubes (not shown) can be connected to the suction arms 18, 19 either before or after the distal end of the tool 15 is inserted through the aperture into the working space. A tube receiver (e.g., receiver 20 of the suction arm 18) is adapted to connect with the suction tube and communicates with an opening in the suction pod (e.g., opening 21 of the suction arm 19) to fit against the tissue to be stabilized. The suction pod is thus connected to a negative pressure (i.e., vacuum) source by the suction tube, generating a suction force at the opening that adheres the arms 18, 19 to the patient's tissue surface.

[0012] Stabilizer tool 15 has an open profile as shown in Figures 5-7, with suction arms 18 and 19 pivoting independently and hub 17 angled to traverse support tube 16. Manipulation of the moving parts can be accomplished with other grasping instruments (e.g., forceps) inserted into the workspace, or remotely from the proximal end (e.g., handle) of the support tube using an internal wire or belt, as described in another embodiment below.

[0013] To reach and hold (via suction) various target areas of the patient's anatomy within the workspace, the present invention uses a hinge mechanism to articulate the distal end components (e.g., suction arms 18, 19 and hub 17). The suction arms 18, 19 are pivotable on the hub 17 about a common axis A such that the arms 18, 19 are movable in a substantially common plane (transverse to axis A). The hub 17 is pivotable about an axis B that is substantially transverse to the longitudinal axis L of the support tube 16. As described in more detail below, the hinge mechanism is coupled with gear-like disks having teeth that can be locked into a desired position. The teeth, serrations, or other keyed surfaces (e.g., any mating surfaces that resist sliding) prevent the hinge from rotating when the components are pressed together.

[0014] 8-11, the hub 17 includes a base portion 22 and a sliding portion 23 comprised of a yoke piece 24 and a link 25. The distal end of the support tube 16 (comprised of two sides 16A and 16B) forms receiving portions 26A and 26B. The proximal end of the base portion 22 has hinge posts (i.e., pillars) 27 and 29 captured in pivot slots 28 and 30 formed in the receiving portions 26A and 26B, respectively. The slots 28 and 30 extend longitudinally of the support tube 16 to allow the hinge posts 27 and 29 to slide. A spring 33 (e.g., a leaf spring) is held in the receiving portion 26B against the post 29 to bias the base portion 22 distally. Another spring (not shown) may be similarly disposed in the receiving portion 26A to bias the post 27 distally. Receiving portions 26A, 26B further define a keyed surface 31 (e.g., a toothed concave surface) that is complementary to and mates with a keyed surface 32 (e.g., a toothed gear shape) on the proximal end of base portion 22. A spring 33 normally spaces surfaces 31 and 32 apart, but when surfaces 31 and 32 are engaged, pivoting of base portion 22 is prevented.

[0015] Link 25 includes a pivot pin 35 extending between side plates 36 and 37. The proximal ends of suction arms 18, 19 include pivot holes 40, 41 that receive pivot pin 35. Yoke piece 24 has upper and lower tabs 42 and a slot 43 between tabs 42. Yoke piece 24 is mounted to base portion 22 such that beams 44 of base portion 22 are slidably captured in slots 43 (see FIG. 11). Tabs 42 are captured in slots 38 of link 25, allowing yoke piece 24 and link 25 to slide together as a unit on base portion 22 between distal and proximal positions. The distal end of base portion 22 is provided with a keyed surface 45 (e.g., a toothed concave surface) that is complementary to and mates with keyed surfaces 46, 47 (e.g., toothed gear shapes) on the proximal ends of suction arms 18, 19. As suction arms 18, 19, along with yoke pieces 24 and links 25, slide proximally toward base portion 22, keyed surfaces 46, 47 engage keyed surface 45, thereby locking the pivot positions of suction arms 18, 19 in place. This gear-like mechanism uses two stacked gear-shaped sections that can rotate (i.e., pivot) simultaneously until the surfaces lock together. This mechanism can optionally be applied at additional pivot points along each arm, as needed, to provide increased flexibility in shaping contact points on tissue.

[0016] To retract the hub 17 and suction arms 18, 19 proximally, a pull cord (i.e., a tow string or string-like member) 48 extends from the proximal end of the support tube, through the support tube 16 and the base portion 22 of the hub 17, and connects to the sliding portion including the suction arms 18, 19. The pull cord 48 passes through an aperture 49 in the yoke piece 24 (FIGS. 10 and 11). An end catch 50 formed as an extension or ball at the distal end of the pull cord 48 has a diameter larger than that of the aperture 49 and is thereby captured in the slot 43. The proximal end of the base portion 22 may include a gap between two toothed gears that provide the keyed surface 32, and this gap is bridged by guide pins 51, 52. The pull cord 48 is threaded between the guide pins 51 and 52, which help to keep the pull cord 48 aligned with the central passage 53 of the support tube 16. The pull cord 48 can be made of metal wire, plastic or cloth string, fiberglass, or other materials. The suction arms 18, 19 can be coupled at their distal ends to the pull cord 48 via other components of a sliding structure, as shown, or can be connected directly to the pull cord, as described below. At the proximal end (not shown) of the pull cord 48, a grip or handle can be provided with a locking mechanism that allows a user to retract the pull cord 48 once all pivot positions are properly set and it is desired to lock the configuration with the pull cord 48 in tension. For example, the tension of the pull cord 48 can be controlled by a movable element (e.g., a threaded fastener) on a handle at the proximal end of the support tube 16.

[0017] As shown in FIG. 12, when pull cord 48 is released, either to reconfigure the stabilizer position or to remove tool 15 from the body, spring 33 urges hinge post 29 distally. FIG. 13 shows recess 54 in receiver 26B that holds spring 33 in pivot slot 30 to bias post 29 distally. A similar spring (not shown) may be provided between slider 23 and base 22 to normally bias keyed surfaces 46, 47 away from keyed surface 45. When pull cord 48 is in a relaxed state, the keyed surfaces disengage, allowing tool 15 to be reconfigured to another open configuration or returned to a closed configuration.

[0018] A vacuum tube (not shown) is connected to each suction arm. The tubes may be bundled. The support tubes may be made of stainless steel, and the vacuum tubes are held in a central passageway of the support tubes. This arrangement may be sealed to help maintain CO2 pressurization within the thoracic cavity to maintain a working space. The stabilizer tool 15 may include a disposable portion and a reusable portion. For example, the distal end of the tool that contacts the heart may use very thin silicone rubber tubing, which tends to be difficult to clean and maintain sterility. The disposable portion may consist of the link 25 and the suction arms 18, 19. Removal of the disposable portion is achieved by releasing the tab 42 from the slot 38. This release may be facilitated by a push button 55 on the yoke piece 24 (Figure 10), which can be pressed from both sides to slide the disposable unit into and out of position.

[0019] 14-16 illustrate another embodiment in which the hub provides another degree of freedom of movement, namely, rolling (i.e., tumbling) about its central longitudinal axis. The modified base portion 58 of the articulation hub 59 is comprised of a proximal subsection 60 and a distal subsection 61 having aligned longitudinal passages 62, 63. As previously described, the pull cord 48 passes through the passages 62, 63 and is captured by the yoke piece 24. The subsections 60, 61 define an axis of rotation (i.e., roll axis) R. The proximal subsection 60 has a first plate 64 facing the distal subsection 61, which has a keyed (e.g., serrated) surface. The distal subsection 61 has a second plate 65 facing the proximal subsection 60, which has a keyed surface complementary to the keyed surface of the plate 64. Distal subsection 61 is rotatable about the roll axis R when pull cord 48 is in a relaxed state and is prevented from rotating about roll axis R when pull cord 48 is in a tensioned state. A spring 66 (e.g., a wave spring) may be disposed between plates 64 and 65 and bias the keyed surfaces apart when pull cord 48 is in a relaxed state, allowing free rotation until tension is again applied through pull cord 48, compressing spring 66 and locking rotational movement.

[0020] Another embodiment of a stabilizer tool 70 is shown in Figures 17-27. As shown in Figure 17, an elongated support tube 71 has a handle 72 at its proximal end and a grasping tool 73 at its distal end. As shown in Figure 19, the grasping tool 73 has suction arms 74, 75 connected by an articulating hub 76 to a pivot mechanism 77 mounted at the distal end of the tube 71. As shown in Figure 18, the handle 72 has suction arm pivot adjustment knobs 78, 79, a suction arm locking knob 80, and a hub pivot adjustment lever 81.

[0021] 20 , the hub 76 includes a base portion 84 and a sliding portion 85. The sliding portion 85 is formed as a pivot shaft that is received in an elongated pivot slot 86 in the base portion 84 and pivot holes 87 in the suction arms 74, 75. The slot 86 is configured to allow the sliding shaft portion 85 to slide between a distal position where the suction arms 74, 75 are pivotable about the axis of the sliding shaft portion 85 and a proximal position where a keyed surface 88 on the base portion 84 and a keyed surface 89, 90 on the suction arms 75, 74, respectively, interlock, thereby preventing the suction arms 74, 75 from pivoting. To retain the assembly, the sliding shaft portion 85 may be rigidly attached (e.g., force-fit) to one of the suction arms 74 or 75 within one of the pivot holes 87. A recess in base portion 84 adjacent slot 86 holds a spring 93 (e.g., a leaf spring) for biasing sliding shaft portion 85 toward a distal position. Suction arms 74, 75 include suction tube receiving portions 91 for attaching a suction tube.

[0022] The proximal end of base portion 84 defines a pivot axis for hub 76 and has a pivot hole 94 that receives the inner ends of a pair of pivot pins 95, 96 of pivot mechanism 77. Pivot mechanism 77 also has a pair of semi-cylindrical receiving members 97, 98 that fit together to form a cylinder and are inserted into support tube 71 at its proximal end. The distal ends of members 97, 98 include aligned pivot holes 100, 101. The outer ends of pins 95, 96 are captured in pivot holes 100, 101, such that base portion 84 is pivotable about an axis perpendicular to the longitudinal axis of tube 71. To control rotation of base portion 84, a flexible drive belt 102 exits tube 71, is wrapped around pulley track 103, and passes radially (i.e., circumferentially) around pivot hole 94. To prevent drive belt 102 from slipping on pulley track 103 , drive belt 102 is formed with ridges 105 that are captured in internal slots 104 in base portion 84 .

[0023] To control the movement of the suction arms 74, 75, respective pull cords 106, 107 (e.g., wires) exit the tube 71 and are looped between openings 110 and 111 in the pivot pins 95, 96 (which maintain the pull cords in an orientation that allows the suction arms 74, 75 to be pulled laterally about their pivot axes). Between the pivot pins 95 and 96, the pull cord 106 is secured within a bore 113 that extends through the suction arm 74. Between the pivot pins 95 and 96, the pull cord 107 is secured within a bore 112 that extends through the suction arm 75. The pull cords 106, 107 cannot slide within the bores 112, 113. Pull cords 106, 107 are looped from handle 72 and secured to suction arms 74, 75, respectively, so that they can be pulled from one side or the other (i.e., rotated like a conveyor belt) to provide translational motion that pivots the suction arms as desired. When pull cords 106, 107 are in a relaxed state (i.e., keyed surfaces not engaged), suction arms 74, 75 are free to pivot. Once the desired position of suction arms 74, 75 is achieved, pull cords 106, 107, respectively, are pulled from both sides to provide tension such that a proximal force applied to suction arms 74, 75 slides shaft portion 85 proximally within slot 86, engaging keyed surfaces 89, 90 with keyed surface 88.

[0024] 21 shows pull cords 106, 107 passing through openings 110 in pivot pin 95 (receiving member 97 has been removed and distal portions of pull cords 106, 107 have been removed for clarity). Pull cord 107 continues for attachment to bore 112 (not shown), while pull cord 106 instead continues to suction arm 74. FIG. 22 shows in more detail the path of pulley track 103 and the capture of ridge 105 in slot 104.

[0025] Handle 72 is shown in more detail in Figures 23-27. A hollow tube 120 (e.g., formed from two semi-cylindrical members) fits over support tube 71 and has a threaded opening 121 for receiving a threaded shaft 122 of locking knob 80. Suction arm adjustment knob 79 has a drive pulley 123 on shaft 124, and suction arm adjustment knob 78 has a drive pulley 125 on shaft 126. Hollow tube 120 defines a side opening 127 that receives shafts 124, 126. Opening 127 is elongated so that shafts 124, 126 can be moved longitudinally to vary the tension of pull cords internally wrapped around pulleys 123, 125. To control the longitudinal position of the pulleys 123, 125, the yoke pieces 131 (only one of which is shown) define pockets 132 for capturing the disks 130 protruding from the distal end of the shaft 122. The pockets 132 have rounded profiles within which the disks 130 can rotate. The yoke pieces 131 have wing extensions 133 with apertures 134 for receiving the shaft 126. Thus, by rotating the knob 80 in the appropriate direction, the positions of the pulleys 123, 125 together can be shifted distally or proximally to achieve a relaxed or tensioned state. While in the relaxed state, the adjustment knobs 78, 79 can be rotated to pull the desired side of the corresponding pull cord proximally (i.e., in a translational motion), thereby pivoting the attached suction arm as desired.

[0026] To control the pivoting of the articulated hub to which the suction arm is attached, the handle 72 includes an adjustment lever 81 connected to a belt pulley 140 via a shaft 141 that passes through a side opening 142 in the tubular member 120. A drive belt 102 is wrapped around the pulley 140 so that rotational movement of the lever 81 manually pivots the base of the hub about its axis. The lever 81 and belt 102 are preferably positioned so that when the lever 81 is parallel to the tubular member 71, the hub is also parallel to the tubular member 71. The belt pulley 140 and pulley track 103 have substantially the same diameter. Therefore, adjusting the orientation angle of the hub and suction arm causes the orientation of the lever 81 to share the same orientation, allowing the user to easily determine the orientation of the suction arm within their body.

[0027] In some embodiments, the interior of the support tube may have a C-shaped cross-section to fit over the suction tube. When inserted, the tube may complete (i.e., completely fill) the circular portion of the device to help prevent air leaks. The tool may have additional wires / strings for manipulating the articulating portion with a push / pull action. The tool may also be configured with an additional flexible tube and nozzle for spraying liquid (e.g., saline) to cleanse / remove blood from around the anastomosis area.

Claims

1. a support tube extending from a proximal end to a distal end, the distal end adapted to be inserted through an incision into a working space within a patient; an articulation hub attached to the distal end of the support tube, the articulation hub having a proximal end that pivots about a first axis substantially transverse to a longitudinal axis of the support tube at the distal end of the support tube; a pair of suction arms attached to the articulation hub at a distal end thereof, the suction arms configured to be attached to a vacuum pressure source, the suction arms configured to adhere to a tissue surface of the patient upon exposure to the vacuum pressure, the suction arms configured to pivot in a common plane at the distal end of the articulation hub, the suction arms having first keyed surfaces at their proximal ends; a pull cord coupled to the suction arm and extending through the support tube from the articulation hub to the proximal end of the support tube; Equipped with the articulation hub is comprised of a base portion and a slider portion, the suction arm is attached to the slider portion, and the base portion has a second keyed surface configured to interlock with the first keyed surface; the pull cord has a relaxed state in which the first and second keyed surfaces can be separated to allow the suction arms to spread apart to grasp the tissue, and the pull cord has a tensioned state in which the first and second keyed surfaces are interlocked to prevent pivoting of the suction arms. Stabilizer for minimally invasive cardiac surgery.

2. 2. The stabiliser of claim 1, wherein the sliding portion of the articulation hub includes a pivot shaft, each of the suction arms has a proximal end with a pivot hole that receives the pivot shaft, and a spring between the base portion and the sliding portion biases the first keyed surface and the second keyed surface apart when the pull cord is in the relaxed state.

3. 2. The stabilizer of claim 1, wherein the pull cord is a first pull cord secured to a first one of the suction arms, and the stabilizer further comprises a second pull cord secured to a second one of the suction arms, each pull cord looped between a respective one of the suction arms and the proximal end of the support tube, and each pull cord configured to provide translational motion to pivot the respective suction arm while in the relaxed state.

4. first and second drive pulleys disposed at the proximal end of the support tube that receive the first and second pull cords; first and second control knobs coupled to the first and second drive pulleys, respectively, for manually imparting the translational motion; a tension control device coupled to the drive pulley movable along the longitudinal axis of the support tube, the tension control device manually moving the drive pulley to obtain the relaxed and tensioned states; The ballast of claim 3 further comprising:

5. the base portion of the articulation hub includes pulley tracks radially disposed about the first axis, and the stabilizer comprises: a drive belt disposed on the pulley track; a belt pulley disposed at the proximal end of the support tube for receiving the drive belt; an adjustment lever coupled to the belt pulley for manually pivoting the base portion about the first axis; The ballast of claim 1 further comprising:

6. 2. The stabilizer of claim 1, wherein the distal end of the support tube includes a receiver configured to pivotally couple with the base, the proximal end of the base having a third keyed surface and the receiver having a fourth keyed surface, the third and fourth keyed surfaces interlocking with each other to prevent pivoting of the articulation hub about the first axis when the pull cord is in the tensioned state.

7. the base portion of the articulated hub is comprised of proximal and distal subsections having aligned longitudinal passages for receiving the pull cord and defining an axis of rotation; the proximal subsection has a first plate having a fifth keyed surface facing the distal subsection, and the distal subsection has a second plate having a sixth keyed surface facing the proximal subsection; the distal subsection is rotatable about the axis of rotation when the pull cord is in the relaxed state, and the distal subsection is prevented from rotating about the axis of rotation when the pull cord is in the tensioned state. The ballast of claim 1 .

8. 8. The ballast of claim 7, further comprising a spring disposed between the proximal subsection and the distal subsection, the spring biasing the fifth keyed surface and the sixth keyed surface apart when the pull cord is in the relaxed state.

9. A support tube extending from a proximal end to a distal end, the distal end adapted to be inserted through an incision into a working space within a patient; an articulation hub attached to the distal end of the support tube, the articulation hub having a proximal end that pivots about a first axis substantially transverse to a longitudinal axis of the support tube at the distal end of the support tube; a pair of suction arms attached to the articulation hub at a distal end thereof, the suction arms configured to be attached to a vacuum pressure source, the suction arms configured to adhere to a tissue surface of the patient upon exposure to the vacuum pressure, the suction arms configured to pivot in a common plane at the distal end of the articulation hub, the suction arms having first keyed surfaces at their proximal ends; a pull cord coupled to the suction arm and extending through the support tube from the articulation hub to the proximal end of the support tube; Equipped with the articulation hub having a base portion and a slider, the suction arm attached to the slider, the base portion having a second keyed surface configured to interlock with the first keyed surface; the pull cord has a relaxed state in which the first and second keyed surfaces can be separated to allow the suction arms to spread apart to grasp the tissue, and the pull cord has a tensioned state in which the first and second keyed surfaces are interlocked to prevent pivoting of the suction arms; the sliding portion of the articulation hub includes a pivot shaft, each of the suction arms has a proximal end with a pivot hole that receives the pivot shaft, and a spring between the base portion and the sliding portion biases the first keyed surface and the second keyed surface apart when the pull cord is in the relaxed state; Stabilizer for minimally invasive cardiac surgery.

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