1. Field of Invention
This invention concerns novel methods and apparatus for medical applications, specifically wound closure applications. More particularly, the invention manipulates blood fluids, or its components, in new ways to close tissue or vascular wounds.
2. Background Information
Numerous medical applications exist where sealing of biological tissue is desired. U.S. Pat. No. 5,510,102 to Cochrum identifies many of these including trauma of liver, spleen, pancreas, lung, bone, etc., cardiovascular and vascular, such as microvascular anastomoses, vascular grafts, intraoperative bleeding, and aortic repair, for thoracic surgery such as lung biopsy, for transplant of heart, renal, pancreas, lung, bone or bone marrow, for neurosurgery such as nerve anastomoses, or CSF leak repair, for endoscopic surgery, such as hemostasis in hepatic trauma, or bile duct repair, for interventional radiology, such as hemostasis for percutaneous liver biopsy or vascular occlusion, for gastrointestinal surgery such as colonic anastomoses, for obstetrics and gynecology such as rectovaginal fistulas, for pediatric and fetal surgery, for plastic surgery and burn repairs such as grafting process of cultured epidermis, for dermatology such as hair transplants, for dental surgery, for ophthalmic cataract surgery, for urology, for correction of urinary fistulas and such others. With such broad application of the present invention possible, one use is selected for method and apparatus illustrative continuity purposes throughout this document. The selected application is sealing of a vascular wound resulting from percutaneous entry as is frequently done in the performance of angiography, angioplasty, and atherectomy procedures.
Percutaneous vascular access is typically done in the context of performing some minimally invasive surgical procedure. Minimally invasive techniques are used to reduce trauma to the patient. Reduced trauma typically translates to improved patient comfort, less procedural complications, and lower costs. The vessel accessed is typically the femoral or radial artery. Access involves placement of an introducer's distal tip beneath the patient's skin and through the arterial wall. To the extent possible, percutaneous access preserves the integrity of tissue covering the artery. As a result, when the introducer is to be removed the arterial access site is not exposed and the arterial wound is preferably closed without cutting down through the overlaying tissue to expose the site.
To accomplish hemostasis at the wound, numerous methods of post-introducer arterial closure have been invented. Most of these are similar to each other in many respects with some novel differentiating characteristic separating them. Many of them rely upon the clotting cascades being initiated at the wound site. Many prior art devices may be broadly classified into two groups, those that passively support onset of the clotting cascades at the wound site and those that actively cause the clotting cascades at the wound site. By example, mechanical methods of holding the wound closed by clamping or suturing to prevent hemorrhaging are passive methods because they merely prevent continual flushing of the site as the clot attempts to take hold. To a lesser degree the body also does this naturally by vascular constriction. The second grouping—active clotting at the wound site—includes those methods which place a clot inducing material at the wound site. Such clot inducing formulations are many and typically either supply thrombin directly or potentially stimulate thrombin release at the wound site.
Disadvantages of the prior art vary based on the method employed. Generally speaking, passive devices like clamping or suturing are generally complex and/or expensive. Clamping for example can be labor intensive to administer manually and is uncomfortable for the patient by any means. Suturing on the other hand is complex and expensive because the wound site is typically small, remote, and blind to the physician placing the suture. Active devices are often costly and potentially dangerous. Active devices typically require placement of a clot-inducing foreign material in the patient which necessitates either expensive pretesting for potential allergic reactions or accepting the occasional adverse reaction which could lead to anaphylactic shock and even death as reported in J. Trauma, 31:408 (1991). Transmission of infectious disease can occur when the material used was manufactured from pooled human blood as reported in Opth. Surg., 23:640 (1992). Autologous preparations like fibrin glue as described in U.S. Pat No. 5,674,394 to Whitmore are well known but significant preparation with the associated labor and material costs are required and typically an additional thrombin material must still be added at the wound site.
Despite the need for a device and method which overcomes the limitations of the prior art, none insofar as is known has been proposed or developed until the present invention.
Accordingly, it will be appreciated that there is a need for an efficient way of closing wounds. The present inventions provide advantages over the prior devices and the prior methods used to close wounds, and also offers other advantages over the prior art and solves other problems associated therewith.