Surgery – Instruments – Electrical application
Reexamination Certificate
2000-03-17
2004-08-03
Peffley, Michael (Department: 3739)
Surgery
Instruments
Electrical application
C600S566000, C606S028000
Reexamination Certificate
active
06770070
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a method of obtaining a lung biopsy sample using minimally invasive methods. More particularly, the invention relates to a method of obtaining a lung biopsy sample percutaneously with a reduced risk of pneumothorax. Still more particularly, the invention relates to an apparatus and method for obtaining a lung biopsy sample and reliably sealing the entry path into the lung to reduce the risk of pneumothorax. Still more particularly the invention relates to an apparatus and method for obtaining a lung biopsy sample and sealing the entry path into the lung via the delivery of thermal energy to a target tissue site or use of a polymer sealant or mechanical closure device.
2. Description of the Related Art
The lungs are the organs for respiration in mammals. They have a set of unique material properties adapted to this function including elasticity, porosity and a large amount of surface area for gaseous exchange to efficiently oxygenate and remove waste gases from the blood. In the adult human, each lung is 25 to 30 cm (10 to 12 in) long and roughly conical. The left lung is divided into two sections or lobes: the superior and the inferior. The right lung is somewhat larger than the left lung and is divided into three lobes: the superior, middle, and inferior. These lobes are divided by the oblique and horizontal fissures. The left lung only has two lobes, an upper and lower. These lobes are divided by the oblique fissure. Both lungs are further divided by bronchopulmonary segments.
The two lungs are separated by a structure called the mediastinum, which contains the heart, trachea, esophagus, and blood vessels. Both right and left lungs are covered by an external membrane called the pleura. The outer layer of the pleura forms the lining of the chest cavity. The inner pleura covers each lung. A vacuum is maintained between these membranes that causes the lungs to expand during inhalation as the diaphragm muscle is pulled down causing the chest cavity to expand.
While the structure of the lung is extremely well suited as a respiratory organ at the same time it makes them susceptible to damage and disease from environmental factors by trapping disease causing pollutants within the structure of the lung. Due to the spread of western industrialized society, factors such as increasing concentrations of air pollution and incidents of smoking are resulting in a worldwide increase in the incidence of lung disease. Smokers and people who live in cities are exposed to substantial levels of carcinogenic air pollutants such as benzene and polycyclic aromatic hydrocarbons (PAHs). Two of the more prevalent disease resulting from these and other risk factors include emphysema and lung cancer. Lung cancer is a particularly insidious and deadly lung disease and each year it kills more Americans than any other type of cancer.
A key factor in the prevention and successful treatment of lung disease is early detection. One of the best tools available to the physician in this regard is the taking of a lung tissue sample or lung biopsy. In fact, biopsy is often necessary or otherwise highly advantageous as an adjunct to other diagnostic methods to improve diagnostic accuracy. Efforts to biopsy the lung have focused on three key requirements: 1) The need to harvest adequate tissue from an organ that is mostly air; 2) the need to obtain a biopsy specimen from within the lung tissue without permitting air to leak either from the outside or from the lung into the pleural space; and 3) the need to have access to the entire volume of the lung. The two currently practiced methods for lung biopsy: transbronchial biopsy and percutaneous biopsy have not been able to adequately address all three needs. In fact, both methods have significant clinical issues and technical drawbacks.
In particular, both methods present the risk of a potentially lifethreatening complication known as pneumothorax due to puncture of the lung by the biopsy needle. A pneumothorax is a collapse of the lung that occurs when the airtight integrity of the lining of the chest cavity (the pleural membrane) is broken due to a penetrating injury or a complication of a lung disease. This causes air to enter and collect in the pleural cavity (which is normally in a partial state of vacuum), collapsing the lung and severely, if not totally, impairing its function. The risk of this complication is considerable, potentially life-threatening and requires immediate medical intervention including surgery to vent air from the chest cavity. A recent ten year study has shown that the risk of pneumothorax for both fine needle biopsy and percutaneous biopsy is 11.7% (Greif J, et al. Percutaneous core needle biopsy vs. fine needle aspiration in diagnosing benign lung lesions Acta Cytol 1999 September-October; 43(5):756-60).
During the procedure of transbronchial biopsy a flexible fiberoptic bronchoscope is employed as a conduit through which a biopsy instrument is passed from the outside of the patient through the airways of the lung into the lung tissue. The use of fiberoptic devices for collecting tissue samples is done as part of a procedure known as fiberscopic-bronchoscopy which is a visual examination of the bronchial tubes. The bronchoscope, which is inserted down the trachea and into the bronchial tubes, has lighting and magnifying devices that enable the physician to see the bronchial surface. During this procedure the physician can obtain samples of cells for later microscopic examination. However, accessing the lung tissue biopsy site via the throat has the drawbacks of requiring that the patient be intubated (a sometimes difficult and time-consuming process) and put under general anesthesia (which increases mortality and morbidity). These and other factors result in the procedure taking considerable time, one to two hours, and burdening the patient with considerable expense due to required personal, equipment and facilities. Also due to size limitations, the distal end of many bronchoscopes, particularly rigid bronchoscopes, cannot be passed any further than the beginning of the segmental bronchi of the lower lobes of the lung. Thus, inaccessibility of significant portions of the lung is another key limitation of transbronchial procedures. Further, the procedure can result in air entering into the pleural space causing partial or complete pneumothorax.
Percutaneous needle biopsy involves introducing a biopsy needle (known as a transthoracic needle) through the chest wall usually after making a small skin incision. This procedure is often necessary, as many areas of the lung are too inaccessible to bronchoscopy, particularly areas abutting the chest wall. However, while the procedure provides increased accessibility and shorter procedure times versus transbronchial procedures, it has significant clinical risks and limited diagnostic accuracy. These risks include pneumothorax, and vessel perforation causing embolism and/or uncontrollable hemorrhage. Pneumothorax in percutaneous biopsy can result from either lung perforation or accidental suction of air into the chest during stylet changes. Pneumothorax is a likely event in percutaneous biopsy due to the sizable injury of the pleural membrane frequently resulting from this procedure.
Depending upon the patient, these risks may be so great that invasive surgical procedures such as open lung biopsy are preferred and/or are the only option. This is the case for patients who are receiving anticoagulants such as coumadin, making them particularly susceptible to uncontrollable pulmonary hemorrhage from inadvertent vessel perforation or other trauma by the biopsy needle. Further, percutaneous biopsy only has a 40-50% sensitivity in the diagnosis of malignant disease; a critical shortcoming.
There are two approaches to percutaneous needle biopsy: core biopsy and needle aspiration. In core biopsy the needle is advanced into tissue for obtaining a core or plug of tissue sample withi
Dehlinger Peter J.
Mahoney Jacqueline F.
Peffley Michael
Perkins Coie LLP
Rita Medical Systems, Inc.
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