The embodiments are generally related to electro-mechanical systems. The embodiments are also related to artificial muscles. More particularly, embodiments are related to electromechanical-based artificial muscles, bio-valves and related devices. Embodiments are also related to devices for assisting natural human organs and body parts assisted by electromechanical-based devices.
The natural human heart and accompanying circulatory system are critical components of the human body and systematically provide the needed nutrients and oxygen for the body. As such, the proper operation of a circulatory system, and particularly, the proper operation of the heart, is critical in the overall health and well being of a person. A physical ailment or condition which compromises the normal and healthy operation of the heart can therefore be particularly critical and may result in a condition which must be medically remedied.
Specifically, the natural heart, or rather the cardiac tissue of the heart, can fail for various reasons to a point where the heart can no longer provide sufficient circulation of blood for the body so that life can be maintained. To address the problem of a failing natural heart, conventional solutions have been offered to provide techniques for which circulation of blood might be maintained.
Some solutions involve replacing the heart. Other solutions maintain the operation of the existing heart. One such solution has been to replace the existing natural heart in a patient with an artificial heart or a ventricular assist device. In utilizing artificial hearts and/or assist devices, a particular problem stems from the fact that the materials used for the interior lining of the chambers of an artificial heart are in direct contact with the circulating blood. Such contact may enhance the undesirable clotting of the blood, may cause a build-up of calcium, or may otherwise inhibit the blood's normal function. As a result, thromboembolism and hemolysis may occur.
Additionally, the lining of an artificial heart or a ventricular assist device can crack, which inhibits performance, even when the crack is at a microscopic level. Moreover, these devices must be powered by a power source, which may be cumbersome and/or external to the body. Such drawbacks have limited use of artificial heart devices to applications having too brief of a time period to provide a real lasting benefit to the patient.
An alternative procedure also involves replacement of the heart and includes transplanting the heart from another human or animal into the patient. The transplant procedure requires removing an existing organ (i.e. the natural heart) from the patient for substitution with another organ (i.e. another natural heart) from another human, or potentially, from an animal. Before replacing an existing organ with another, the substitute organ must be “matched” to the recipient, which can be, at best, difficult, time consuming and expensive to accomplish. Furthermore, even if the transplanted organ matches the recipient, a risk exists that recipient's body will still reject the transplanted organ and attack it as a foreign object. Moreover, the number of potential donor hearts is far less than the number of patients in need of a natural heart transplant. Although use of animal hearts would lessen the problem of having fewer donors than recipients, there is an enhanced concern with respect to the rejection of the animal heart.
In an effort to continue use of the existing natural heart of a patient, other attempts have been made to wrap skeletal muscle tissue around the natural heart to use as an auxiliary contraction mechanism so that the heart may pump. As currently used, skeletal muscle cannot alone typically provide sufficient and sustained pumping power for maintaining circulation of blood through the circulatory system of the body. This is especially true for those patients with severe heart failure.
Another system developed for use with an existing heart for sustaining the circulatory function and pumping action of the heart, is an external bypass system, such as a cardiopulmonary (heart-lung) machine. Typically, bypass systems of this type are complex and large, and, as such, are limited to short term use, such as in an operating room during surgery, or when maintaining the circulation of a patient while awaiting receipt of a transplant heart. The size and complexity effectively prohibit use of bypass systems as a long-term solution, as they are rarely portable devices. Furthermore, long-term use of a heart-lung machine can damage the blood cells and blood borne products, resulting in post surgical complications such as bleeding, thromboembolism function, and increased risk of infection.
Still another solution for maintaining the existing natural heart as the pumping device involves enveloping a substantial portion of the natural heart, such as the entire left and right ventricles, with a pumping device for rhythmic compression. That is, the exterior wall surfaces of the heart are contacted and the heart walls are compressed to change the volume of the heart and thereby pump blood out of the chambers. Although somewhat effective as a short-term treatment, the pumping device has not been suitable for long-term use.
Typically, with such compression devices, a vacuum pressure is needed to overcome cardiac tissue/wall stiffness, so that the heart chambers can return to their original volume and refill with blood. This “active filling” of the chambers with blood limits the ability of the pumping device to respond to the need for adjustments in the blood volume pumped through the natural heart, and can adversely affect the circulation of blood to the coronary arteries. Furthermore, natural heart valves between the chambers of the heart and leaching into and out of the heart are quite sensitive to wall and annular distortion. The movement patterns that reduce a chamber's volume and distort the heart walls may not necessarily facilitate valve closure (which can lead to valve leakage).
Therefore, mechanical pumping of the heart, such as through mechanical compression of the ventricles, must address these issues and concerns in order to establish the efficacy of long term mechanical or mechanically assisted pumping. Specifically, the ventricles must rapidly and passively refill at low physiologic pressures, and the valve functions must be physiologically adequate. The mechanical device also must not impair the myocardial blood flow of the heart. Still further, the left and right ventricle pressure independence must be maintained within the heart.
Another major obstacle with long term use of such pumping devices is the deleterious effect of forceful contact of different parts of the living internal heart surface (endocardium), one against another, due to lack of precise control of wall actuation. In certain cases, this cooptation of endocardium tissue is probably necessary for a device that encompasses both ventricles to produce independent output pressures from the left and right ventricles. However, it can compromise the integrity of the living endothelium.
Mechanical ventricular wall actuation has shown promise, despite the issues noted above. As such, devices have been invented for mechanically assisting the pumping function of the heart, and specifically for externally actuating a heart wall, such as a ventricular wall, to assist in such pumping functions.
One particular type of mechanical ventricular actuation device that has been developed is a Left Ventricular Assist Device (LVAD), which is designed to support the failing heart. Such a device must augment systolic function. Diastolic function must also be augments or at the very least, not worsened, while allowing blood flow between the right and left ventricular portions of the heart. If the LVAD relies on a pump mechanism, the heart must still be able to beat 45 to 40 million times per year. The LVAD must therefore be durable and should function flawlessly or permit some degree of cardiac function in case of device failure. Such devices and/or systems must also permit a minimal risk for blood clot production and should be resistant to infection.
Other bodily functions rely on physical manipulation of muscles. For example, urinary and anorhectal sphincter valves control incontinence when operating properly. Sphincter valves are also founding the digestive tract where food passes from the esophagus into the stomach. Sphincter valves, however, tend to malfunction or lose range of operation. For example, after childbirth or as the human body ages. Surgery will sometimes correct incontinence in patients or reduce occurrences of Gastro esophageal reflux disease (GERD). Unfavorable conditions, however, often return or are sometimes not correctable using current treatments. Current artificial sphincter prototypes are composed of elastic and inflated with air. Erosion, probably from continuous high tonic pressure of inflated balloon in the urinary tract, can lead to infection and device failure. Therefore, there is a need for artificial means of restoring sphincter valve operation for digestive conditions. It is the inventors' belief that sphincter valve operation can be assisted or replaced using electromechanical systems.
Tendons are the thick fibrous cords that attach muscles to bone. They function to transmit the power generated by a muscle contraction to move a bone. Use of tendons can fail following trauma or because of arthritis. It is the inventors' belief that the movement of hands, fingers, arms and legs that lose mobility can be assisted using electromechanical systems.
It is believed by the present inventors that a solution to the aforementioned problems associated with conventional ventricular assist devices and sphincter valves involves the use of electromechanical systems, such as mini-machines and so-called micro electromechanical system (MEMS) technology. It is also believed that electromechanical systems can offer alternatives to other muscular dysfunctions encountered by patients due to age, disease or accidental causes.
“MEMS” is an abbreviation for Micro Electro Mechanical Systems. This is a rapidly emerging technology combining electrical, electronic, mechanical, optical, material, chemical, and fluids engineering disciplines. As the smallest commercially produced “machines”, MEMS devices are similar to traditional sensors and actuators although much, much smaller, e.g. complete systems are typically a few millimeters across, with individual features/devices of the order of 1-100 micrometers across. MEMS devices are manufactured either using processes based on Integrated Circuit fabrication techniques and materials, or using new emerging fabrication technologies such as micro injection molding.
These former processes involve building the device up layer by layer, involving several material depositions and etch steps. A typical MEMS fabrication technology may have a 5 step process. Due to the limitations of this “traditional IC” manufacturing process MEMS devices are substantially planar, having very low aspect ratios (typically 5-10 micro meters thick). It is important to note that there are several evolving fabrication techniques that allow higher aspect ratios such as deep x-ray lithography, electro deposition, and micro injection molding.
MEMS devices are typically fabricated onto a substrate (chip) that may also contain the electronics required to interact with the MEMS device. Due to the small size and mass of the devices, MEMS components can be actuated electrostatically (piezoelectric and bimetallic effects can also be used). The position of MEMS components can also be sensed capacitively. Hence the MEMS electronics include electrostatic drive power supplies, capacitance charge comparators, and signal conditioning circuitry. Connection with the macroscopic world is via wire bonding and encapsulation into familiar BGA, MCM, surface mount, or leaded IC packages.
A common MEMS actuator is the “linear comb drive” shown in
The following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the embodiments and is not intended to be a full description. A full appreciation of the various aspects of the embodiments can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
It is a feature of the embodiments to provide eletromechanical system for use to assist or replace human muscles, muscle/tendon operation, and sphincter valves.
It is another feature of the embodiments to provide an electromechanically-based ventricular assist device.
It is another feature of the embodiments to provide an electromechanically-based ventricular assist device in the form of at least one of: a cardial patch and a whole-heart wrap/jacket.
It is another feature of the embodiments to provide an electromechanically-based bio valve.
It is another feature of the embodiments to provide an electromechanically-based bio valve that can be used as at least one of: an artificial anorectal sphincter, an artificial urinary sphincter, and an artificial gastroesophageal sphincter.
It is another feature of the embodiments to provide electromechanically-based muscle and tendon operation within human extremities.
It is another feature of the embodiments to provide an electromechanically-based muscle-tendon interface.
In accordance with more features of the embodiments, a system is described that includes an electromechanical-based biological system interface, at least one sensor to monitor biological functions, a microprocessor for analyzing biological functions measured by the at least one sensor, a controller for causing operation of the electromechanical-based to operate at least one of a ventricular assist device, bio valve and muscle-tendon interface, under direction of the microprocessor.
In accordance with more features of the embodiments, a system is described that includes integrated wire network provides sensory feedback, controlled contraction or relaxation of any single actuator or actuator groups, programmable contraction or expansion, and reflexic contraction or expansion from natural internal pacemakers.
In accordance with more features of the embodiments, a system is described that includes programmable contraction and expansion of artificial muscle regions and sub-regions, or artificial valves, programmable response to stimulus, and resistance to mechanical failure since multiple components operate in parallel.
It is yet a further aspect of the embodiments to provide for a ventricular assist device and system that is composed sheet of MEMS-based material that can be wrapped around a failing heart to support ventricular activities thereof.
Additionally, each electromechanical element is linkable, contractile, durable and electrically insulated to performance characteristics by design. For example, a sheet can be configured from a flexible and/or a pliable material, and may be arranged as a sheath and/or in a mesh arrangement of the MEMS elements.
The embodiments can be used for assistance of the following bodily functions/systems: Abdominal wall substitutes; Diaphragm substitutes; Artificial muscles such as skeletal muscle, Ocular muscle, Visceral muscle; Tendons as a muscle-bone interface; conduits; Sphincter Valves associated with reservoirs, the esophagus, prostrates, and the urinary bladder.
The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate at least one embodiment and, together with the detailed description of the invention, serve to explain the principles of embodiments.
The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.
A natural human heart includes a lower portion comprising two chambers, namely a left ventricle and a right ventricle, which function primarily to supply the main pumping forces that propel blood through the circulatory system, including the pulmonary system (lungs) and the rest of the body, respectively. Hearts also includes an upper portion having two chambers, a left atrium and a right atrium, which primarily serve as entryways to the ventricles, and also assist in moving blood into the ventricles. The interventricular wall or septum of cardiac tissue separating the left and right ventricles is defined externally by an interventricular groove on the exterior wall of the natural heart. The atrioventricular wall of cardiac tissue separating the lower ventricular region from the upper atrial region is defined by atrioventricular groove on the exterior wall of the natural heart. The configuration and function of the heart is known to those skilled in this art.
Generally, the ventricles are in fluid communication with their respective atria through an atrioventricular valve in the interior volume defined by heart. More specifically, the left ventricle is in fluid communication with the left atrium through the mitral valve, while the right ventricle is in fluid communication with the right atrium through the tricuspid valve. Generally, the ventricles are in fluid communication with the circulatory system (i.e., the pulmonary and peripheral circulatory system) through semilunar valves. More specifically, the left ventricle is in fluid communication with the aorta of the peripheral circulatory system, through the aortic valve, while the right ventricle is in fluid communication with the pulmonary artery of the pulmonary, circulatory system through the pulmonic or pulmonary valve.
The heart basically acts like a pump. The left and right ventricles are separate, but share a common wall, or septum. The left ventricle has thicker walls and pumps blood into the systemic circulation of the body. The pumping action of the left ventricle is more forceful than that of the right ventricle, and the associated pressure achieved within the left ventricle is also greater than in the right ventricle. The right ventricle pumps blood into the pulmonary circulation, including the lungs. During operation, the left ventricle fills with blood in the portion of the cardiac cycle referred to as diastole. The left ventricle then ejects any blood in the part of the cardiac cycle referred to as systole. The volume of the left ventricle is largest during diastole, and smallest during systole. The heart chambers, particularly the ventricles, change in volume during pumping. The natural heart, or rather the cardiac tissue of the heart, can fail for various reasons to a point where the heart can no longer provide sufficient circulation of blood from its operation so that bodily function and life can be sustained.
Referring to
Indicated in
As indicated at point 3, sheet 40 thus provides a contractile function. Relaxation can occur in the system by reversing the electrical polarity in diastole, or by allowing the heart muscles to expand into relaxed states between cycles while power is no longer applied. It should be appreciated that each electromechanical element among said plurality of elements composing sheet 10 is electrical insulated. Electrical contact can be facilitated between a controller 20 and the mesh 10 by band 50, which can operate as a conduit for electrical wires and feedback wiring 18. The wiring connects positive contacts associated with the electromechanical elements composed of the mesh 10. A common ground can be provided using the mesh material, or separate contacts to each electromechanical device can be provided; however, it can be appreciated that less wiring is needed where a common ground is provided using the mesh 10.
Also shown in
The electromechanical devices can be integrated within the bands 13 or firmly along the conduit 50 wherefrom the electromechanical devices can pull on the bands 13 in order to assist the heart with pumping. It can be noted that MEMS-based device described with respect to
The teeth should never be allowed to touch, because a short will cause the comb drive actuator to malfunction. Other come drive actuator do not have a fixed based, but have two moving members supported by an insulated spring-like material. The insulated spring-like material causes the comb drive actuators members to move away from each other when power is no longer applied to each member. A signal can be used to causes comb drive actuators to move into and away from each other in accordance with the signal.
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When a sensor located above the sphincter valve 105 is activated because it senses food traveling into the esophagus, then the valve is cause to relax or open. The sensor can be a pressure transducer, electrical contact sensor, or electro-impulse detector. A pressure transducer can sense the weight of food or water within the esophagus above the valve. It can now be appreciated that a similar sensor-valve configuration can be employed in other parts of the human body. For example, the sphincter valve 105 can be implanted in a patient's rectum or after the bladder. The valve can help patient control incontinence. Such an application would be helpful for cancer patients that have lost functionality due to rectum or prostrate cancer, or adults that can no longer control urinary function because of age or numerous childbirths.
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A controller 60 is generally in communication with said plurality of electromechanical elements 30/40, while a microprocessor 90 is generally in communication with controller 60. Microprocessor 90 and controller 60 can be implemented in the context of a pacemaker 90, which is generally in communication with electrical devices. Microprocessor 90 can be implemented as a central processing unit (CPU) on a single integrated circuit (IC) computer chip. Microprocessor 90 generally functions as the central processing unit of apparatus 70, and can interpret and execute instructions, and generally possesses the ability to fetch, decode, and execute instructions and to transfer information to and from other resources over a data-transfer path or bus.
Note that each electromechanical element among said plurality of electromechanical elements can contract toward one another in systole and away from one another by a reversal of poles in diastole. Additionally, each electromechanical element among said plurality of electromechanical elements will preferably sequentially contract the heart horizontally and thereafter, vertically. As indicated previously, each electromechanical element is electrical insulated. Sheet 10 can be configured from a flexible or pliable material. Tube 35 can be configured from a flexible or pliable material.
Unique features of the electromechanical-biological system (EBS) described herein includes: integrated wire network, sensory feedback, controlled contraction or relaxation of any single actuator or actuator groups, programmable contraction or expansion, reflexic contraction or expansion from natural internal pacemakers, programmable contraction and expansion of any regions and sub-regions, programmable response to stimulus, resistance to mechanical failure since multiple components operate in parallel or over a grid configuration.
As a cardiac patch, the present invention offers a simpler design than a whole-heart wrap design and can be used to target a specific location of failure along an organ. The cardiac patch can be surgically affixed to cardiac regions and surfaces along a heart. For example, a patch can be placed over area of myocardial scar, aneurysm, or defect. The patch is sutured in place over the afflicted area. The electromechanical system within the patch can be programmed to contract and expand with heart cycles that are being sensed using sensors located near or within the patch and monitored by a microprocessor. Using this configuration, sub regional contraction and expansion is optimized with external programming and radiologic real-time visualization. Other advantages of the patch system are that it provides self-contractile material to reinforce weakened or absent myocardium. The externally applied patch need not contact blood. Coagulation problems are avoided. Surgical excision of defective tissue is avoided.
Because artificial Anorectal Sphincters are desperately needed by fecal incontinence patients (stomates patients with a surgically removed rectum or anus and a diverting colostomy). An electromechanical system can be surgically implanted to surround native anorectum or surgically translocated conduit (colon pulled into place formerly occupied by the anorectum). Baseline conformation is relaxation of upstream canal and relative contraction of downstream canal. Manual switch activation or direct signal transduction from the sacral and inferior hemorrhoidal nerves allows defecation by stimulating upstream canal contraction and downstream canal relaxation. Reflex continence is maintained when the switch is not activated or by voluntary impulses. In these conditions, propagating impulses sensed from upstream bowel produce a reflex increased capacitance of the upstream sleeve and temporary hypercontraction of the downstream sleeve. A relatively thin artificial sphincter assist produces a programmable limit of pressure on tissue.
Now, an artificial Urinary Sphincter can be provided in accordance with feature of the present invention to prevent urinary Incontinence caused by female stress or side affects of male surgery for prostrate issues. An Artificial Gastroesophageal Sphincter provided utilizing features of the present invention can prevent gastroesophageal reflux. A cylindrical tube including electroemchanical functioning can be surgically implanted to fit around the gastroesophageal junction in a patient. Relatively contracted in baseline conformation to prevent gastroesophageal reflux. The Artificial Gastroesophageal Sphincter of the present invention is induced to relax by sensed distension of upstream esophagus. Anti-reflux prosthetic devices of the past (e.g., Angelchick prosthesis) can now be abandoned because of prior problems with prosthesis migration or erosion.
The embodiments and examples set forth herein are presented to best explain the present invention and its practical application and to thereby enable those skilled in the art to make and utilize the invention. Those skilled in the art, however, will recognize that the foregoing description and examples have been presented for the purpose of illustration and example only. Other variations and modifications of the present invention will be apparent to those of skill in the art, and it is the intent of the appended claims that such variations and modifications be covered.
The description as set forth is not intended to be exhaustive or to limit the scope of the invention. Many modifications and variations are possible in light of the above teaching without departing from the scope of the following claims. It is contemplated that the use of the present invention can involve components having different characteristics. It is intended that the scope of the present invention be defined by the claims appended hereto, giving full cognizance to equivalents in all respects.
The embodiments of the invention in which an exclusive property or right is claimed are defined as follows. Having thus described the invention what is claimed is:
This application is a continuation-in-part of U.S. patent application Ser. No. 10/923,357, entitled “Micro electromechanical machine-based ventricular assist apparatus,” which was filed with the United States Patent and Trademark Office on Aug. 20, 2004, and which is incorporated herein by reference herein in its entirety.
Number | Date | Country | |
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Parent | 10923357 | Aug 2004 | US |
Child | 11007457 | Dec 2004 | US |