Surgery – Internal organ support or sling
Reexamination Certificate
1999-10-15
2001-06-05
Lacyk, John P. (Department: 3736)
Surgery
Internal organ support or sling
Reexamination Certificate
active
06241655
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a device for locally immobilizing a beating heart, in particular, for the purpose of carrying out anastomosis between a bypass conduit and a coronary vessel of the anterior wall of the left ventricle of the heart, comprising a fork-shaped platform with two fork blades which extend essentially parallel and form an intermediate space between them.
Minimally invasive operating techniques are the trend and experience keen interest, particularly today with the background of the necessity for saving on costs. In this respect, it is not, however, exclusively the costs which are of concern. The reduction in the preoperative, intraoperative and postoperative trauma, the shortened operating and anesthetic times, the quicker healing of wounds, shorter in-patient times and less wound pain as well as the cosmetic result are also important arguments for minimally invasive operating techniques. In all fields of surgery attempts are being made to replace the standard procedures by minimally invasive variations. For example, reference is merely made to the video-controlled trephine technique for gynecological procedures.
Cardiosurgery procedures with their low mortality and morbidity in relation to the size of the operation first became possible during the 1950s as a result of the development of the heart-lung machine. This allows operations to be carried out on an immobilized and bloodless heart for a period of time of several hours. For several decades operations on hearts with a heart-lung machine were the golden standard.
In a substantial development, specific coronary operations were later carried out on a beating heart with minimally invasive operating techniques, wherein the use of the heart-lung machine became superfluous. The motivation for this course of action was the increasing knowledge about the side effects and disadvantages of the cardiopulmonary bypass (CPB). The contact of the blood with plastic surfaces of the heart-lung machine leads to an activation of the so-called coagulation cascade and the complement system. To prevent any formation of blood clots in the heart-lung machine as a result of this and therefore to a blockage thereof, high doses of heparin are required. As a result of the complete elimination of blood-clotting effected as a result, complications with bleeding may occur during and after procedures using heart-lung machines. As a result, the administration of foreign blood with all its possible consequences (hepatitis, HIV, inter alia) may become necessary. The blood platelets which are essential for normal blood clotting are also, in some cases, impaired considerably in their number and also in their functioning due to a procedure with a heart-lung machine and this again entails the risk of an increase in bleeding complications.
It is not, therefore, surprising that one result of randomized prospective studies with larger numbers of patients was that the patients who had operations on a beating heart without a heart-lung machine had, postoperatively, a statistically significantly lower loss of blood than the patients who were operated on with a heart-lung machine. The fact that the entire sternum normally has to be opened up during procedures with a heart-lung machine can lead to postoperative pain in the wound area but also to disorders during the healing of wounds and instabilities of the sternum. Additional side effects of procedures with a heart-lung machine are neurological complications which are attributed to the extracorporeal circulation. For example, small microclots but also air embolisms may reach brain arteries where they trigger strokes. An additional source of thromboembolic complications may be fine arterioscleroses in the area of the aorta which may be divulsed as a result of the manipulations carried out thereon (connection to the heart-lung machine and clamping off or lateral clamping out of the aorta). Moreover, it is known for not just a few patients to have neurological failures to a slight degree or psychiatric peculiarities (up to 30 percent) following a procedure with a heart-lung machine and cardioplegic ventricular standstill.
In comparison with this, the minimally invasive supply of the most important vessel of the left-ventricular anterior wall (LAD artery) without a heart-lung machine offers numerous advantages. The operation may be performed more quickly by an experienced surgeon than a procedure with a heart-lung machine. The patients have a smaller scar and thus a cosmetically better result is achieved. The sternum retains some of its stability since it is opened up only partially. This causes less wound pain and makes a generally uncomplicated healing phase of the bone possible. In the case of the LIMA/LAD (sternum artery/coronary vessel) procedure, the most important vessel of the heart (LAD) is supplied with the best bypass conduit (LIMA). Up to 80 percent of the entire blood requirements of the heart may be covered by the LAD artery. After a single LIMA onto the LAD, even when additional stenoses exist in smaller branches, most of the patients have no troubles after a successful operation even when the other stenoses remain untreated. Nevertheless, these stenoses, insofar as they are present, should be dilated after a successful minimally invasive LIMA/LAD procedure with a then lesser risk from a prognostic point of view since the LAD has been taken care of beforehand. If the patency rate of the various bypass types onto the various heart vessels is observed, what has been said above becomes even clearer. The sternum artery supply of the LAD has a 10 year patency rate of over 93 percent. In contrast to this, the vein bypasses can already display changes in the vessel inner walls after a few years, and the patency rate of vein bypasses, depending on the vessel to which they have been sutured, is only between 40 and 80 percent for 10 years.
Additional advantages with minimally invasive surgery are the short anesthetic times, extubation generally taking place on the operating table, a stay in the intensive care unit of only a few hours and an overall stay in hospital of approximately two to four days. This is advantageous for the patient and costs can be reduced. Furthermore, as a result of the smaller wound area fewer adhesions occur between pericardium and heart which can be of importance for any later re-operations. Moreover, it is reported in studies that the occurrence of cardiac dysrhythmia during the postoperative period of time following minimally invasive heart surgery procedures is less.
To carry out the anastomosis between LIMA and LAD, the anastomosis area must be immobilized at the beating heart in order to be able to carry out the approximately 15 stitches in an area of a few millimeters with the required precision.
The LIMA/LAD procedure on the beating heart is known and is practiced. In this respect, a so-called mini-sternotomy is carried out on the ventilated patient. A skin incision of approximately eight centimeters in length is made beginning at approximately two centimeters above the metasternum as far as the level of the fourth intercostal space (ICR). Subsequently, a partial median sternotomy is carried out as far as the left third ICR. The LIMA is prepared under direct view of the eye as far as approximately the second ICR. Subsequently, the clotting time of the blood is protracted by administering 5000 to 7500 units of heparin intravenously. Subsequently, the LAD is looped around and thereby occluded distally and proximally of the area selected for the anastomosis. During the end-to-side anastomosis between LIMA and LAD carried out subsequently with a continuous 8-0 suture, it is of greatest significance for the quality of the anastomosis and thus for the success of the operation as a whole how successfully the anastomosis area is stabilized.
Various tools have been developed for this and some of these have to be held by an assistant or secured in various ways. These tools either have to be pressed onto the operating area under high pressure or hav
Cadugan Joseph A.
Lacyk John P.
Lipsitz Barry R.
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