Surgery – Instruments – Surgical mesh – connector – clip – clamp or band
Reexamination Certificate
1998-12-24
2001-06-05
Jackson, Gary (Department: 3731)
Surgery
Instruments
Surgical mesh, connector, clip, clamp or band
C606S139000
Reexamination Certificate
active
06241742
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the general art of surgery, and to the particular field of means and methods associated with anastomoses.
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 patients 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 performed currently 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 the technology played a major role in advancing the whole area of cardiac surgery. The heart-lung machine was invented in the 1950's but 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 was isolated from the circulation, it was no longer perfused. After twenty to thirty minutes of ischemia, irreparable damage occurred and no matter how good the repair, the heart function was frequently inadequate to allow the patient to survive. Cardioplegia, a solution which is generally cold and high in potassium, changed everything. This development occurred in the 1970's. This allowed very satisfactory protection of the heart so the surgeon could perform an unhurried repair and still expect the heart to work afterward.
A secondary consequence of these developments was the decline in interest in technology to facilitate heart surgery. When speed of the surgery was initially of utmost importance, all sorts of developments were proposed to speed surgery. Therefore, the art in the 1960's and 1970's contained numerous examples of such devices.
Now with an increased incentive to reduce costs, there is a renewed interest in redesigning cardiothoracic procedures. A few pioneering surgeons are now performing minimally invasive procedures whereby 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 and reduces the cost of the operation by eliminating the heart lung bypass machine.
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). Below the IMA lies the pericardium and the heart. The pericardium is opened exposing the heart. At this point, the LAD may be dissected from the fissure of the heart and suspended up with soft ligatures to isolate the artery from the beating heart. Some companies are making a special retractor to gently apply pressure to the heart muscle to damp the movement right at the LAD. A small arteriotomy is performed in the LAD and the graft IMA is sutured to the LAD.
Traditionally, to gain access to the cardiac vessels to perform this procedure the sternum is sawn in half and the chest wall is separated. Although this procedure is well perfected the patient suffers intense pain and a long recovery.
Until recently all bypass graft procedures have been performed by hand suturing the 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.
The push for less invasive surgical approaches is fueling interest in many areas that were abandoned long ago- including that of coronary fastening and valve replacement. 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. Any imprecise placement of the sutures may cause a distortion of the anastomosis which may cause stenosis at this 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. To accomplish this feat of precision on a moving target is extremely difficult. To make matters worse, the site is often bloody due to the fact that 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 is inadequate for the following reasons:
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 the artery from the movement of the beating heart can damage the vessel or cause myocardial injury (MI).
In addition to the problem of placing sutures accurately one must make an incision through the artery wall to open the artery. 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 branches.
Without cardioplegia, one must also provide blood flow to the heart muscle while the heart is beating, therefore, after the initial arteriotomy, the surgical field is very bloody and obsc
Christakis George
Spence Paul A.
Williamson IV Warren P.
Jackson Gary
Limbach & Limbach LLP
Origin Medsystems Inc.
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