Surgery – Instruments – Surgical mesh – connector – clip – clamp or band
Reexamination Certificate
2000-08-17
2003-05-20
Worrell, Danny (Department: 3765)
Surgery
Instruments
Surgical mesh, connector, clip, clamp or band
Reexamination Certificate
active
06565581
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the general art of surgery, and to the particular field of anastomosis.
BACKGROUND OF THE INVENTION
In the United States, there are currently as many as 300,000 coronary artery bypass graft (CABG) procedures performed on patients annually. Each of these procedures may include one or more graft vessels which are hand sutured. Until recently, coronary artery bypass procedures have been performed with the patient on cardiopulmonary bypass whereby the heart is stopped with cardioplegia and the surgery is performed on an exposed, stationary heart.
The vast majority of CABG procedures currently performed are accomplished by opening the chest wall to gain access to the coronary vessels. Through the use of heart lung bypass machines and a drug to protect the heart muscle, the heart is stopped and remains still during the procedure. In this setting, the surgeon has ample time and access to the vessels to manipulate hand suturing instruments such as forceps, needle holders and retractors.
However, with increasing costs of hospital stays and increased awareness by patients of other minimally invasive surgical procedures, interest in developing a minimally invasive CABG procedure is increasing. Hospitals need to reduce costs of procedures and patients would like less post-operative pain and speedier recovery times.
In the past, two significant developments in technology played a major role in advancing the whole area of cardiac surgery. The heart-lung machine was invented in the 1950's and underwent significant improvement in design to become a reliable clinical device in the 1960's. The heat-lung machine allows the surgeon to take the heart out of the blood circulation system to work on it in isolation.
The second major development was in myocardial protection. When the heart is isolated from the circulation, it is no longer perfused. After twenty to thirty minutes of ischemia, irreparable damage may occur and no matter how good the repair, the heart function may be inadequate to allow the patient to survive. The development of cardioplegia, a solution which is generally cold and high in potassium, changed everything. This development occurred in the 1970's. Cardioplegia allows very satisfactory protection of the heart so the surgeon can perform an unhurried repair and still expect the heart to work afterward.
An unforeseen consequence of these technology developments was the decline in interest in technology to facilitate and expedite heart surgery. When speed of the surgery was of utmost importance, many developments were proposed to speed surgery. Therefore, while the art in the 1960's and 1970's contained numerous examples of devices intended to expedite heart-related surgery, the incidence of such devices declined after about 1970.
With an increased incentive to reduce costs, there is a renewed interest in expediting cardiothoracic procedures. A few pioneering surgeons are now performing minimally invasive procedures in which the coronary artery bypass is performed through a small incision in the chest wall. There are some surgeons that believe that the best way to perform a minimally invasive coronary artery bypass procedure is to perform the procedure on a beating heart, i.e., without heart-lung bypass and cardioplegia. This minimizes the time it takes to perform the procedure, reduces the cost of the operation by eliminating the heart lung bypass machine and reduces recovery time.
In the case of minimally invasive procedures on a beating heart, the surgeon starts by making a mini-thoracotomy between the fourth and fifth ribs and, sometimes, removing the sternal cartilage between the fourth or fifth rib and the sternum. The space between the fourth and fifth ribs is then spread to gain access to the internal mammary artery (IMA) which is dissected from the wall of the chest. After dissection, it is used as the blood supply graft to the left anterior descending artery of the heart (LAD). The pericardium and the heart are located below the IMA. The pericardium is opened exposing the heart. At this point, the LAD may be dissected from the fissure of the heart and suspended with soft ligatures to isolate the artery from the beating heart. A small arteriotomy is performed in the LAD and the graft IMA is sutured to the LAD.
Heretofore, access to the cardiac vessels is gained for this procedure by sawing the sternum in half and separating the chest wall. Although this procedure is currently well perfected, the patient suffers intense pain and generally requires a long recovery period.
Until recently all bypass graft procedures have been performed by hand suturing tiny vessels together with extremely fine sutures under magnification. The skills and instruments required to sew extremely thin fragile vessel walls together have been perfected over the last twenty years and are well known to the surgical community that performs these procedures.
In the “open chest” surgical setting, the surgeon has adequate access and vision of the surgical site to manipulate the anatomy and instruments. However, in minimally invasive procedures, this access is often severely restricted thereby inhibiting such procedures.
Furthermore, the interest in less invasive surgical approaches is promoting concomitant interest in many areas that were abandoned long ago, including coronary fastening and valve replacement. In view of the above-discussed developments, the inventors have thus identified a need for a device and a method to perform CABG surgery on a beating heart.
Some surgeons are attempting minimally invasive CABG procedures using femoral artery bypass access rather than opening the chest for bypass via the aorta. However, since use of cardioplegia requires additional support and expense during the anastomosis procedure, the inventors believe that it is best to attempt to fasten the anastomosis while the heart is beating. However, this procedure when performed with a hand suturing technique is very imprecise due to the translation of movement from the beating heart to the suspended artery. This may cause imprecise placement of the suture needles. Imprecise placementof the sutures may cause a distortion of the anastomosis which may cause stenosis at the junction.
The sutures used for this procedure are extremely fine (0.001″ in diameter) and are placed less than 1 mm apart. As one can imagine it is difficult enough to place suture needles the size of a small eyelash into a vessel wall with placement accuracy of better than 1 mm; yet to accomplish this feat of precision on a moving target is even more difficult. To make matters worse the site is often obscured by blood because the heart has not been stopped.
Therefore, there is a need for a means and method which permits the forming of a precise anastomosis without requiring the stopping of a beating heart. Still further, there is a need for performing such an anastomosis in a minimally invasive manner.
The current method of hand suturing has the several drawbacks, including the following.
On a beating heart it may be difficult to place the sutures with the position precision required. In a beating heart procedure the surgeon can attempt to minimize the deleterious effects of the movement by using suspension or retraction techniques. However, it is impossible to isolate all movement of the vessel during an anastomosis procedure.
Methods that attempt to stabilize and isolate an artery from the movement of the beating heart may damage the vessel or cause myocardial injury (MI).
In addition to the problem of accurately placing sutures, an incision through the artery wall to open the artery must be made. This, too, is a delicate procedure even on a still heart because the incision must be of a precise length. It is also critical to not penetrate the back wall or side wall of the vessel which will lead to complications. The placement of the initial incision is of paramount importance. The surgeon must pick a suitable location free from calcium deposits, fat and side
Allen Douglas P.
Berky Craig B.
Christakis George
Huddleston Matthew J.
Leimbach Delbert Ted
Hurley Shaun R
Origin Medsystems Inc.
Thelen Reid & Priest LLP
Worrell Danny
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