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SURGICAL DEVICES FOR IMPOSING A
NEGATIVE PRESSURE TO STABILIZE THE
CARDIAC TISSUE DURING SURGERY
The present application is a continuation of application 5 Ser. No. 09/440,106, filed Nov. 15, 1999 now U.S. Pat. No. 6,852,075 and titled "Surgical Devices for Imposing a Negative Pressure To Stabilize Cardiac Tissue During Surgery," pending, which is a divisional of application Ser. No. 08/870,687, filed Jun. 6, 1997, now U.S. Pat. No. 6,032,672, 10 which is a divisional of application Ser. No. 08/603,328, filed Feb. 20, 1996, now U.S. Pat. No. 5,727,569, each of which are hereby incorporated by reference thereto, in their entireties.
Surgeries to treat disease in the heart, particularly block- 15 ages in coronary vessels, are becoming increasingly common and necessary to treat atherosclerosis and other conditions causing reduced blood flow to the heart. For many years, surgeons have performed "open-heart" surgery to repair defects in the heart and the associated cardiovascular 20 system. As these procedures have become more common and more costly, a need has developed for techniques to make cardiac surgical procedures less traumatic to the patient. The necessity of attaching a surgical patient to a cardiopulmonary bypass (CPB) apparatus is a primary con- 25 tribution to the trauma inherent in traditional procedures. To attempt to alleviate the trauma and side effects of CPB, surgeons have begun performing cardiac surgeries without stopping the heart. To successfully perform such surgery, several challenges must be met. One particular problem 30 confronting the surgeon who operates on the beating heart is the difficulty in performing extremely delicate surgical procedures while the contractions of the heart muscles cause the surface of the heart to continuously move.
To attempt to restrict the motion of heart at the particular 35 area where the surgeon is working, the surgeon may pass at least a pair of sutures through the exterior tissue layers of the heart. By pulling the sutures in opposite directions, the tissue is stretched, and the motion caused by the contractions of the heart muscles is reduced or partially compensated. This 40 technique is not completely effective in preventing the natural motion of the heart and requires extra time to place the sutures, and, additionally, may cause damage to the cardiac tissue when the sutures are placed or manipulated. Preferably, the surgeon would be able to fix the motion of the 45 cardiac tissue containing or adjacent to an area where surgery is to be performed without the need to attach or manipulate additional sutures. The ability to fix the position of the cardiac tissue in a region of the heart would permit the surgeon to perform delicate surgical procedures on the 50 beating heart while the portion of the heart on which the surgery is performed remains substantially motionless throughout the procedure.
SUMMARY OF THE INVENTION 55
This invention is devices and techniques which use a negative pressure (vacuum) applied through a surgical instrument, to fix the position of a portion of the surface of a beating heart so that a surgical procedure can be more 60 easily performed. The devices disclosed herein apply a negative pressure at several points on the outer surface of the heart such that a portion of the exterior tissue of the heart is fixed in place by the suction imposed through the surgical instrument. Because the negative pressure introduced 65 through the instrument -s the position of a region of tissue, the instrument remains at a constant distance from the
particular portion of the heart where the surgery is being performed. In this configuration, the device may also serve as a support or platform so that other surgical instruments or devices can be advantageously used at the site. In certain preferred embodiments, the devices described herein have structures to facilitate the use of additional surgical instruments such that the placement of the negative pressure instrument permits the surgeon to advantageously manipulate the other instruments used during the surgery.
The negative pressure is preferably imposed through a plurality of ports which may be disposed in a substantially planar surface of the instrument which contacts the cardiac tissue. The ports are preferably oriented such that the pressure is applied at several points over the target area to fix the position of the tissue and to reduce any trauma to the tissue caused by the negative pressure.
DESCRIPTION OF THE FIGURES
FIG. 1 is an embodiment of the invention having a substantially annular housing with a plurality of suction ports disposed about the periphery of the instrument and having openings in the bottom surface which contacts the heart.
FIG. 2 is a dome-shaped or semi-spherical embodiment having a plurality of suction ports disposed about the periphery of the bottom surface and having several instrument ports in the dome portion through which additional surgical instruments may be introduced, positioned, or manipulated.
FIG. 3 is a section of a substantially circular embodiment showing a preferred configuration for the suction ports and a pressure conducting chamber for introducing the negative pressure to each suction port.
FIG. 4 is an embodiment of the instrument, in use, which is fixed on the surface of the heart and has additional surgical instruments operably associated therewith to facilitate a graft being inserted to form an anastomosis between the internal mammary artery (IMA) and the left anterior descending (LAD) artery.
FIG. 5 is an alternative embodiment of the invention wherein the suction ports for imposing the negative pressure are affixed to a shaft which may be part of a hand-held device and are contained in a block where a plurality of individual suction ports are arranged in an array.
FIG. 6 is a plurality of suction ports contained within a block having attached thereto a pair of vacuum lines for introducing a negative pressure to each suction port.
FIGS. 7 and 7A are sectional views of the block showing an alternate configuration for the suction ports and the pressure conducting space.
FIG. 8 is an alternative embodiment for an array of suction ports having vacuum tubes which run the length of the block and are oriented to be substantially perpendicular to a passage space leading to each suction port.
FIGS. 9 and 9A are a hand held instrument having a removable block, wherein the instrument has a receiving means to reversibly receive the block.
DETAILED DESCRIPTION OF THE
This invention is surgical instruments and techniques which advantageously apply a negative pressure to the surface of the heart so that a portion thereof is maintained at a fixed position during a surgical procedure. The negative pressure is introduced to the instrument and is applied at
several points over the surface of the heart proximate to or surrounding the portion of the heart whose position is desired to be fixed during the procedure. The instruments feature several suction ports which are brought into contact with the heart, followed by the application of a negative 5 pressure through the instruments, to fix the position of the tissue based on the placement of the instrument. The Instruments may also contain a sealed, airtight, pressure conducting chamber for operably connecting to a pressure inlet for communicating the negative pressure to the suction parts. 10 Alternatively, each suction port may have a dedicated vacuum line attached thereto.
The shape of the instrument may be varied depending on the particular application or the clinical diagnosis for an individual patient. In some embodiments, the shape of the 15 instrument is defined by a housing forming a complete or partial, substantially annular, ring having the suction ports disposed about the periphery of the bottom surface of the housing. The suction ports are contained within the base of the instrument and the opening of the suction ports are 20 contained in the bottom surface of the instrument which may be substantially planar or may be shaped to conform to the surface of the heart.
In another embodiment, the operative portion of the instrument may be defined by one or more arrays of suction 25 ports which are substantially linear. The suction ports may be contained in a block which has at least one vacuum line attached thereto. This design is particularly suitable for an instrument having a shaft affixed thereto for positioning the block containing the suction ports. The shaft may be fixed to 30 a rigid support during the procedure or may be part of a hand-held instrument having a handle structure adapted to be grasped by the human hand. In a preferred embodiment, the hand-held instrument contains a pair of shafts having a block and suction port assembly at each end thereof. The 35 shafts are connected at an intermediate portion by a pivot which allows the suction port assemblies to move relative to one another, to be oriented and manipulated by hand, and to be locked into place in a desired configuration.
An embodiment having more than one movable member in which suction ports are contained offers the advantage that a negative pressure may be first imposed through the suction ports of each movable member to fix the tissue, followed by manipulation of the individual members which 45 causes the tissue to be stretched or oriented such that one portion of the cardiac tissue is fixed in position by one movable member and can be oriented relative to another portion fixed by a second movable member.
The negative or vacuum pressure imposed may be varied 50 depending on the design of the instrument, the orientation of the ports, and the amount of pressure needed to hold a particular region of the heart in place. When manipulating the instruments of this invention, it is not, desired to exert a downward force on the instrument once the instrument 55 engages the cardiac tissue because the tissue could be damaged by being drawn into the suction ports, thus risking interruption of blood flow and ischemic or reperfusion injury to the cardiac tissue. However, once a negative pressure is imposed, the instrument may be drawn away from the heart 60 such that the portion of the surface tissue fixed by the suction ports is slightly elevated relative to the remainder of the heart.
Referring to FIGS. 1 and 3, an embodiment of the invention is an instrument comprised of an annular housing 65 1 which could have an alternate shape depending on the design and clinical application of the instrument. For
example, the body of the instrument has a housing which may be a portion of a circle, an oval, semi-oval, U-shape, or linear member.
The portion of the housing 1 which contains the suction ports 2 has a bottom surface 6 which rests against the surface of the heart and therefore should be substantially planar or curved to the extent necessary to simultaneously bring the suction ports 2 into conforming contact with the heart. Referring to FIGS. 1 and 3, one embodiment of the invention has suction ports 2 equally spaced about the circumference of the housing 1. For purposes of stability, it is preferred that each suction port 2 be substantially equidistant from each adjacent port and spread over the entire portion of the instrument at the points of contact to the heart so that the instrument is more stably affixed to the surface of the heart when a negative pressure is imposed. As described in detail below, the housing 1 may also have one or more instrument ports 9 to facilitate introducing a surgical instrument to the site of the surgery to function on or in proximity to the fixed portion of the cardiac tissue.
The interior of the housing 1 may be further comprised of a means for introducing a negative pressure to the suction ports 2. For example, each suction port 2 may have a dedicated vacuum line 3 for introducing a negative pressure to each suction port 2. However, it is preferred that a single vacuum line 3 introduce the negative pressure via an inlet 5 which leads to an airtight, sealed, and pressure conducting chamber 4 contained within the annular housing 1 which in turn communicates the negative pressure to each suction port 2. Thus, by connecting a negative pressure source to the inlet 5, the negative pressure is introduced to the instrument through inlet 5, thereby creating a negative pressure in the pressure conducting chamber 4 which is communicated to each suction port 2. The housing may also have at least one instrument port 9 comprised of an opening that preferably traverses the width of the housing and is shaped to receive an instrument. In use, the surgeon may advantageously rely on the housing 1 as a platform for other instruments which may advantageously be used at the portion of the heart fixed in place by the negative pressure. The instrument port 9 may be a simple opening in the housing I or may be designed to operably receive a specific instrument as described in more detail below.
In use (See FIG. 4), the instrument is gently positioned on the surface of the heart by manipulating the position of the housing 1 such that each suction port 2 rests against the cardiac tissue. Once the instrument is positioned on the surface of the heart, the negative pressure is applied through vacuum line 3 and inlet 5 while the housing may be gently manipulated to insure that the negative pressure is causing the cardiac tissue to become fixed to each suction port 2. Once the suction ports become functionally attached to the surface of the heart, the portion of the surface of the heart becomes fixed relative to the instrument. Once the negative pressure is applied, the instrument may be attached to a stable support such as a rib retractor or other structure which does not move relative to the beating heart.
Referring to FIG. 2, a dome-shaped or semi-spherical embodiment of the invention has a plurality of suction ports 2 spaced about the periphery of the bottom surface 6 of the dome portion 8 such that the entire instrument is fixed to the cardiac tissue at the point of each of the several suction ports 2. As with the above embodiment, it is preferred that each suction port 2 be pneumatically connected via an air-tight pressure conducting chamber 4. The base of the instrument is comprised of a substantially flat bottom surface 6 wherein the opening of each of the suction ports 2 is flush at the