Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2000-04-19
2004-04-06
Mendez, Manuel (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S071000, C604S072000, C604S141000, C604S275000
Reexamination Certificate
active
06716190
ABSTRACT:
FIELD OF THE INVENTION
This invention includes various medical devices and systems for use in surgical and interventional procedures. More particularly, the invention relates to devices and systems for the delivery and injection of therapeutic and diagnostic agents, solutions or injectates into bodily tissue, bodily substances or synthetic materials attached to bodily tissue, such as an artificial graft. Additionally, the invention relates to methods of delivering and injecting a solution at a target site within the body for the treatment or diagnosis of that target site.
BACKGROUND OF THE INVENTION
Despite the continual advances in medical technology, particularly in the treatment of heart disease, vascular disease, cancer, pain, allergies, orthopedic repair and many other diseases and conditions, there are a significant number of patients for whom conventional surgical and interventional therapies are not feasible or are insufficient to treat the disease or condition. For many patients, medical treatment with drugs and the like is the only feasible treatment available.
There have been many recent advances in drug therapies, particularly with regard to cell or site-specific therapeutics (as opposed to systemic therapeutics) such as pharmacologic agents (e.g., anesthetics and analgesics) and biologic agents (e.g., genetically engineered material). Unlike the systemic administration of therapeutics, typically taken orally or given intravenously, much of the effectiveness of cell- or site-specific therapeutics is based on the ability to accurately and precisely deliver the therapeutics to the targeted site within the body.
Needle injection devices are the most commonly used means for the site-specific administration of agents or solutions. Although there have been advances in needle-based drug delivery/injection systems, these systems have significant shortcomings and disadvantages. These shortcomings and disadvantages are exemplified, for example, in gene therapy applications—the implantation of genetic material or engineered cells in specific targets in the human anatomy to create a therapeutic or preventative effect.
Depending on the disease being treated, gene therapy can be angiogenic or anti-angiogenic. The intended result of angiogenic therapy is the promotion of angiogensis—a complex biological process that results in the growth of new blood vessels. Angiogenic therapy has been used experimentally for treating, for example, cardiac ischemia, coronary artery disease (e.g., atherosclerosis), and ischemia in peripheral vascular beds. Conversely, anti-angiogenic therapy involves the reduction in the proliferation of blood vessels, for example, to cut-off the supply of blood to a tumor or to proliferating pannus-type tissue, and to inhibit the abnormal growth of retinal vessels that leads to blindness.
An important factor in achieving the desired result of gene therapy is direct exposure of the genetic material to a specific target site for a sustained period of time. This is particularly challenging for gene therapies that require delivering genetic material to the nuclei of cells. Depending on the location of the targeted tissue and the type of condition being treated, exposure of the genetic material to the target site may involve direct approaches, such as an open or less invasive surgical approach, or endovascular approaches by means of a catheter. With any approach, there are significant challenges in the delivery of genetic material to the appropriate cells of the patient in a way that is specifically targeted, efficient and safe.
For optimum “up regulation” of the gene therapy agent, the agent must undergo some atomization in order to be effectively perfused within the target site. If the gene therapy drug is not sufficiently atomized (i.e., broken up into very small micro-particles), dispersion and then absorption of the drug may be greatly reduced, resulting in minimal to no positive affect on the patient. Needle-based syringes are not capable of such atomization and, instead, deliver the injectate in the form of a bolus, which is less likely to be effectively dispersed and absorbed within tissue.
Moreover, in certain applications of gene therapy, it is important to minimize the systemic exposure of the gene therapy agent in order to avoid unwanted side-affects. The use of a needle or other penetrating means to inject the targeted tissue area unavoidably involves making a hole into the target site. This results in much of the injectate leaking back out of the hole, and being released systemically throughout the body or being wasted. This also results in increased treatment costs and requires more injections, time and agent to achieve the desired affect.
Gene therapy has been used, for example, to create angiogenesis in hypoxic (i.e., oxygen-deprived) heart tissue. In a cardiac surgical procedure, the angiogenic solution is typically delivered by making a number of syringe injections, typically in a grid-like pattern, directly though the epicardium (i.e., the outer surface of the heart) at the ischemic portion of the myocardium. An equivalent endocardial approach (i.e., through the inside surface of the heart) involves delivering a catheter employing a distal needle within a ventricular chamber and injecting the angiogenic solution through the endocardium to the myocardium. The intent of both approaches is to cause the cells in the target tissue to express the desired growth factor protein continuously for a desired time period. Other means of delivering cardiac angiogenesis agents include injecting the agent within the pericardial sac (i.e., intrapericardial), within the coronary arteries (i.e., intracoronary) or directly into the myocardium (i.e., the middle layer of the heart wall).
Although some recent clinical studies have suggested that there is some marginal resulting angiogenic response with syringe
eedle-based injection, there are definite disadvantages of employing a syringe
eedle-based injector or other tissue-penetrating device. For example, myocardial ischemia typically involves an affected surface area in the range of approximately 3 mm
2
to 10 mm
2
. A single needle injection in ischemic tissue can only provide a solution dispersion in a much smaller area defined by the size of the needle and the limited ability of the agent to diffuse through the tissue. Thus, multiple needle-based injections may be required in order to sufficiently disperse the solution over the entire affected area. As the number of injections increases, the procedure time is increased and a greater volume of the gene therapy agent is required to effectively treat the ischemic area. More time and greater drug volume increase the cost of the procedure.
Furthermore, it is known that needle injections or penetration into the tissue can traumatize or destroy tissue cells and, as a result, increase a patient's risk of post-operative arrhythmia. This is particularly due to the difficulty in precisely controlling the penetration of the needle during injection. The more injections or penetrations, the greater the cell destruction and risk of arrhythmia. Still another disadvantage of multiple needle-based injections of growth factor is the need to carefully track the location of each injection site so as to prevent the accidental delivery of growth factor to non-diseased tissue.
There are some gene therapies that do not involve needle-based drug delivery. Instead, indwelling catheters and drug-infused stents have been used for releasing the therapeutic agent in a steady, controlled-release fashion. These approaches present a greater risk of releasing the agent systemically. Additionally, it is more difficult to assess the actual dosing of the target area that takes place. Thus, these approaches have the disadvantages of being less effective, not as safe, and more costly than injections.
Another condition in which site-specific or local drug delivery is commonly employed is in the treatment of peripheral vascular disease (such as deep vein thrombosis and embolisms). One such treatmen
Glines Robert C.
Weller Gary B.
Han Mark K.
Mendez Manuel
Pennie & Edmonds LLP
Sci-Med Life Systems, Inc.
LandOfFree
Device and methods for the delivery and injection of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device and methods for the delivery and injection of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device and methods for the delivery and injection of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3233228