Surgery – Internal organ support or sling
Reexamination Certificate
2000-07-24
2003-08-05
Hindenburg, Max F. (Department: 3736)
Surgery
Internal organ support or sling
Reexamination Certificate
active
06602183
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to invasive devices and methods for treatment of the heart, and specifically to devices and methods for controlling the heart muscle during surgery.
BACKGROUND OF THE INVENTION
Heart surgery is often accompanied by the induction of cardioplegia (elective stopping of essentially all cardiac activity by injection of chemicals, selective hypothermia, mechanical stabilization, or electrical stimuli). In humans, induced global cardioplegia is nearly always practiced in conjunction with cardiopulmonary bypass.
Recently, minimally-invasive methods of cardiac surgery have been developed, in which the heart is approached through an incision made between the ribs, without sternotomy. It is sometimes preferred that, rather than inducing cardioplegia, the surgeon mechanically restrains a portion of the heart on which a surgical procedure, such as a bypass graft, is to be performed. Various tools and methods have been developed for this purpose, such as: (a) a suction cup-based stabilization platform (e.g., the Utrecht Octopus); (b) mechanical stabilization devices, such as the Ultima OPCAB System, produced by Guidant, Inc. (Indianapolis, Ind.); (c) the Octopus 2 or the EndoOctopus device, both produced by Medtronic, Inc. (Minneapolis, Minn.); (d) a U-shaped metal foot and other stabilizers produced by Genzyme Surgical Products, Inc. (Tucker, Ga.); (e) the Octopus Suction stabilizer, produced by Medtronic GmbH, Germany; and (f) CardioVations mechanical stabilizers produced by Ethicon Endo-Surgery (Cincinnati, Ohio).
An article entitled “Coronary artery bypass grafting without cardiopulmonary bypass and without interruption of native coronary flow using a novel anastomosis site restraining device (‘Octopus’),” by Borst et al., Journal of the American College of Cardiology, 27(6) (May 1996), pp. 1356-1364, which is incorporated herein by reference, describes use of the Octopus suction-generating device during experimental surgery on in situ pig hearts.
Such mechanical restraint of the heart muscle requires that substantial force, e.g., pressure or vacuum, be applied, which can cause tissue trauma. The effects of mechanical stabilization are described in an article, “The effects of mechanical stabilization on left ventricular performance,” by Burfeind et al., European Journal of Cardio-Thoracic Surgery, 14(1998), pp. 285-289, which is incorporated herein by reference.
SUMMARY OF THE INVENTION
It is an object of some aspects of the present invention to provide improved methods and apparatus for regulating motion of the heart.
It is a further object of some aspects of the present invention to provide improved methods and apparatus for reducing motion of the heart during minimally-invasive and open-chest surgery.
It is yet a further object of some aspects of the present invention to provide improved methods and apparatus for applying mechanical force to reduce motion of the heart during minimally-invasive and open-chest surgery.
It is still a further object of some aspects of the present invention to provide improved methods and apparatus for reducing motion of the heart during minimally-invasive and open-chest surgery, while minimizing or substantially eliminating injury to the heart resulting from the motion reduction.
In preferred embodiments of the present invention, cardiac control apparatus inhibits motion of a segment of a patient's heart, while allowing the heart to continue to pump blood. The reduction in motion of the segment, as provided by these embodiments of the present invention, is typically used to enable a surgeon to perform minimally-invasive surgery or open-chest surgery, generally without inducing global cardioplegia or requiring cardiopulmonary bypass. The cardiac control apparatus comprises a stabilization element, which has a surface that is applied to the heart in order to reduce motion thereof. Additionally, a plurality of suction ports are positioned on the surface of the stabilization element. When the element is applied to the segment of the heart, the ports apply suction to the segment of the heart, so as to maintain contact between the heart and the stabilization element, and to thereby reduce motion of the segment. Preferably, the ports are configured such that if one of the suction ports loses contact with the surface of the heart, at least one of the other ports will continue to apply suction to the heart. In this manner, the loss of contact substantially does not inhibit the overall functioning of the cardiac control apparatus.
By contrast to these embodiments of the present invention, prior art mechanical stabilizers (such as the Medtronic Octopus) fix a plurality of suction ports to the stabilization element in a configuration that assures that if even one of the suction ports loses contact with the heart, then all of the suction ports will fail to operate. In order to avoid this eventuality, prior art mechanical stabilizers must apply a high level of suction through each of the ports (e.g., 400 millibars), so as to guarantee that throughout the medical procedure, all of the suction ports maintain their contact with the heart. The inventors believe that the application of such a strong suction to the epicardium risks injuring the affected tissue. This structural drawback of prior art stabilizers derives from their use of a single suction line that is directly coupled to all of the ports. Thus, if one of the ports even temporarily loses contact with the heart, then it effectively causes a short-circuit, whereby that port becomes the path of least resistance for air to flow into the suction line, and the desired negative air pressure at the other suction ports disappears.
Therefore, an advantage of these embodiments of the present invention is that significantly lower levels of suction can be applied through every port, because at least some of the suction ports will continue to function even if some others of the suction ports have lost contact with the surface of the heart. It is believed that these lower levels of suction (typically under 200 millibars) will substantially reduce or eliminate injury to the heart responsive to the application of suction thereto.
In a preferred embodiment of the present invention, each of the suction ports is coupled by a respective suction line to a vacuum source, typically external to the stabilization element. In this configuration, each suction port acts substantially independently of each of the other ports, and is therefore unaffected by whether the other ports are in contact with the heart.
Alternatively, at least one of the suction lines has a plurality of suction ports coupled thereto. This configuration allows greater simplicity of the stabilization element, by reducing the number of suction lines used to hold the surface of the heart in contact with the stabilization element. Preferably, a sufficient number of suction lines are utilized such that even if one of the ports on a multi-port suction line fails—thereby generally disabling the other ports on the same line—one or more other ports not coupled to the same line will still continue to function. Optionally, some or all of the ports coupled to the multi-port suction line are coupled thereto through respective valves, which are adapted to close when the suction port loses its seal with the surface of the heart. In this manner, even when a plurality of ports are coupled to the same line, the failure of one of the ports does not adversely affect the functioning of the other ports.
For some applications of the present invention, a plurality of ports on the surface of the stabilization element are coupled through respective small orifices to a relatively-large chamber, typically within the stabilization element. The chamber is coupled, in turn, to the vacuum source. Preferably, the volume of the chamber is sufficiently large and the cross-sectional areas of the orifices are sufficiently small, such that if one of the suction ports loses its seal with the heart, and air enters the chamber through the o
Levi Tamir
Rousso Benny
Dippert William H.
Hindenburg Max F.
Inpulse Dynamics NV
Reed Smith LLP
Szmal Brian
LandOfFree
Enhanced suction-based cardiac mechanical stabilizer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Enhanced suction-based cardiac mechanical stabilizer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Enhanced suction-based cardiac mechanical stabilizer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3114892