Patent Application
20090171379
The present invention relates to methods and devices for forming a restriction in a pathway, and in particular to fluid logic systems and methods for controlling fluid pressure in a restriction system.
Obesity is becoming a growing concern, particularly in the United States, as the number of obese people continues to increase, and more is learned about the negative health effects of obesity. Morbid obesity, in which a person is 100 pounds or more over ideal body weight, in particular poses significant risks for severe health problems. Accordingly, a great deal of attention is being focused on treating obese patients. One method of treating morbid obesity has been to place a restriction device, such as an elongated band, about the upper portion of the stomach. Gastric bands have typically comprised a fluid-filled elastomeric balloon with fixed endpoints that encircles the stomach just inferior to the esophageal-gastric junction to form a small gastric pouch above the band and a reduced stoma opening in the stomach. When fluid is infused into the balloon, the band expands against the stomach creating a food intake restriction or stoma in the stomach. To decrease this restriction, fluid is removed from the band. The effect of the band is to reduce the available stomach volume and thus the amount of food that can be consumed before becoming “full.”
With each of the above-described food restriction devices, safe, effective treatment requires that the device be regularly monitored and adjusted to vary the degree of restriction applied to the stomach. With banding devices, the gastric pouch above the band will substantially increase in size following the initial implantation. Accordingly, the stoma opening in the stomach must initially be made large enough to enable the patient to receive adequate nutrition while the stomach adapts to the banding device. As the gastric pouch increases in size, the band may be adjusted to vary the stoma size. In addition, it is desirable to vary the stoma size in order to accommodate changes in the patient's body or treatment regime, or in a more urgent case, to relieve an obstruction or severe esophageal dilatation. Traditionally, adjusting a hydraulic gastric band requires a scheduled clinician visit during which a huber needle and syringe are used to permeate the patient's skin and add or remove fluid from the balloon. More recently, implantable pumps have been developed which enable non-invasive adjustments of the band. An external programmer communicates with the implanted pump using telemetry to control the pump. During a scheduled visit, a physician places a hand-held portion of the programmer near the gastric implant and transmits power and command signals to the implant. The implant in turn adjusts the fluid levels in the band and transmits a response command to the programmer.
While such techniques are successful in adjusting the band pressure, there remains a need for improved techniques. Conventional hydraulic gastric banding devices exert a continuous restricting force on the stomach to reduce the size of the upper stomach and to restrict the passage of food from the upper to the lower stomach. However, side effects and complications of conventional gastric banding devices include erosion of the exterior stomach tissue resulting from the constant pressure of the band on the exterior stomach. In addition, hydraulic bands do not offer stable banding over time. Liquid within the bands diffuses slowly through the elastomer. Hydraulic bands therefore cannot guarantee the optimal configuration of the band over time. Multiple adjustments to maintain the optimal configuration of the band are required, increasing the cost and the number of medical visits. Also, adjustment of the band requires puncture of the patient's skin, resulting in discomfort for the patient and an increased risk of infection.
Accordingly, there remains a need for methods and devices for regulating a hydraulic restriction system.
Methods and systems are generally provided for automatically regulating a restriction in a pathway. In one embodiment, a self-regulating restriction system is provided and includes both a restriction device configured to receive fluid to form a restriction in a pathway and a fluid logic system coupled to the restriction device and configured to regulate an amount of fluid in the restriction device in response to a fluid pressure to thereby control the size of the pathway. The fluid logic system can include one or more fluid reservoirs and one or more valves coupled between the fluid reservoir(s) and the restriction device. In one exemplary embodiment, the fluid logic system defines one or more pre-set pressure limits that allow valves to be configured such that when a pressure of fluid in the restriction device is less than or greater than the pre-set pressure limit(s) the valve(s) can move from a closed to an opened position to allow fluid to flow between the fluid reservoir(s) and the restriction device. More specifically, pre-set pressure limits can include a minimum pre-set pressure limit that allows the valve(s) to be configured such that when the pressure of fluid in the restriction device is less than the minimum pre-set pressure limit the valve(s) can open to allow fluid flow from the fluid reservoir(s), which in a preferred embodiment is a high pressure fluid reservoir, to the restriction device. When the pressure of fluid in the restriction device is raised to be equal to and/or greater than the minimum pre-set pressure limit, the valve(s) can be configured to close to stop fluid flow from the fluid reservoir(s) to the restriction device. Likewise, pre-set pressure limits can also include a maximum pre-set pressure limit that allows the valve(s) to be configured such that when the pressure of fluid in the restriction device is greater than the maximum pre-set pressure limit the valve(s) can open to allow fluid flow from the restriction device to the fluid reservoir(s), which in a preferred embodiment is a low pressure fluid reservoir. When the pressure of fluid in the restriction device is lowered to be equal to and/or less than the maximum pre-set pressure, the valve(s) can be configured to close to stop fluid flow from the restriction device to the fluid reservoir(s). Embodiments that include any combination of a minimum and maximum pre-set pressure limit and a high and low pressure fluid reservoir can be used in a fluid logic system, and in at least one embodiment of a fluid logic system, minimum and maximum pre-set pressure limits can be used with high and low pressure fluid reservoirs. Further, one or more valves can be configured to be operational with any such system that includes any combination of the minimum and maximum pre-set pressure limits and the high and low pressure fluid reservoirs, including an embodiment that has both minimum and maximum pre-set pressure limits and high and low pressure fluid reservoirs. The pre-set pressure limit(s) of the fluid logic system can also be fixed or adjustable, for instance by adjusting a pressure of fluid in the fluid reservoir(s) or by adjusting one or more parameters of the valve(s).
While the fluid logic system can include one or more valves and reservoirs, in one embodiment a logic valve is used to regulate the amount of fluid in the restriction device in response to a fluid pressure. More particularly, the logic valve can be configured to regulate fluid flow in response to a pressure of fluid in the restriction device. In one embodiment, the logic valve can be coupled to a biasing mechanism that is effective to apply a biasing force to the logic valve that counteracts a force applied to the logic valve by a pressure of fluid in the restriction device. In an exemplary embodiment, the biasing mechanism can be adjustable to allow the biasing force to be adjusted, which in turn allows the one or more pre-set pressure limits of the fluid logic system to be set and/or adjusted. While logic valves can be configured in a variety of ways, in one embodiment the valve includes a first port in fluid communication with the fluid reservoir(s) and a second port in fluid communication with the restriction device. The logic valve can also include one or more seals configured to regulate fluid flow between the first and second ports to thereby regulate fluid flow between the fluid reservoir(s) and the restriction device. A third port can also be included, for instance by placing it in fluid communication with the fluid reservoir(s), and further, the seal(s) can be configured to regulate flow between the second port and the third port to thereby regulate fluid flow between the fluid reservoir(s) and the restriction device. More particularly, the logic valve can be configured to regulate fluid flow between the first, second, and third ports in response to a pressure of fluid in the restriction device. In one exemplary embodiment, the first port can be in communication with a high pressure fluid reservoir and the third port can be in communication with a low pressure fluid reservoir.
Another type of valve that can be used in the fluid logic system is a regulator valve. In one embodiment, the regulator valve can include a bi-stable beam that is effective to selectively open and close the regulator valve to regulate fluid flow in response to a pressure of fluid in the restriction device. More particularly, the bi-stable beam can be configured to buckle when a force is applied to the beam, which in turn can cause the regulator valve to open to allow the flow of fluid between the fluid reservoir(s) and the restriction device. A biasing mechanism can be coupled to the bi-stable beam and effective to apply a biasing force to the beam to direct it toward a buckled configuration, while a force applied to the beam by a pressure of fluid in the restriction device can be effective to counteract the biasing force. In another embodiment of a regulator valve, the regulator valve can include a gate movable between an opened position, in which fluid can flow from the fluid reservoir(s) to the restriction device, and a closed position, in which fluid can be prevented from flowing between the fluid reservoir(s) and the restriction device. The gate can be movable based on a variety of forces that are applied to the gate, but in an exemplary embodiment a biasing mechanism applies a biasing force to the gate to bias the gate toward the opened position and a force applied by a pressure of fluid in the restriction device is effective to counteract the biasing force of the biasing mechanism to move the gate toward the closed position. Further, the biasing mechanism can be adjustable to allow the biasing force to be adjusted, which in turn allows the one or more pre-set pressure limits of the fluid logic system to be set and/or adjusted.
In another embodiment, the one or more valves of the fluid logic system can be a check valve. The check valve can be configured to have a cracking pressure, which is a pressure at which the valve is configured to open or close to allow or prevent fluid flow between the reservoir(s) and the restriction device in response to a particular parameter, for example a pressure of fluid in the restriction device. In some embodiments, the check valve can have multiple cracking pressures. In an exemplary embodiment, the fluid logic system includes two fluid reservoirs and two check valves, and further, the first check valve is coupled to a high pressure fluid reservoir and the second check valve is coupled to a low pressure fluid reservoir. The first and second check valves can have separate cracking pressures. When a pressure of fluid in the restriction device is less than the cracking pressure of the first check valve, the first check valve can be configured to open and release fluid from the high pressure fluid reservoir into the restriction device. When a pressure of fluid in the restriction device increases to an amount equal to and/or greater than the cracking pressure of the first check valve, the check valve can be configured to close to stop fluid flow from the high pressure fluid reservoir to the restriction device. Likewise, when a pressure of fluid in the restriction device is greater than the cracking pressure of the second check valve, the second check valve can be configured to open and release fluid from the restriction device to the low pressure fluid reservoir. When a pressure of fluid in the restriction device decreases to an amount equal to and/or less than the cracking pressure of the second check valve, the check valve can be configured to close to stop fluid flow from the restriction device to the low pressure fluid reservoir. In an exemplary embodiment, the check valve can be adjustable. For example, the cracking pressure of the check valve can be adjusted, for instance, by adjusting a pressure of fluid in the fluid reservoir(s) or by adjusting one or more parameters of the adjustable check valve. In one embodiment, the check valve can be a magnetic check valve.
In addition to being able to incorporate a variety of valves, the fluid logic system can also incorporate a variety of fluid reservoirs. In one exemplary embodiment, the fluid reservoir can be a high pressure fluid reservoir. One example of such a high pressure fluid reservoir is an osmotic pump. In another embodiment, the high pressure fluid reservoir can include a chamber containing chemical reactants and configured to react to generate a high pressure. Further, the chamber can include a port configured to allow the chemical reactants to be altered to change the high pressure output of the fluid reservoir. Various types of reactants can be used, but in one embodiment the resultant reaction is an exothermic reaction.
A method for maintaining a restriction in a pathway is also provided. In one exemplary embodiment, a restriction device can be implanted in a patient to form a restriction in a pathway such that the restriction in the pathway corresponds to an amount of fluid contained within the restriction device. A fluid logic system can be coupled to the restriction device and configured to regulate an amount of fluid in the restriction device in response to a fluid pressure to thereby control the size of the pathway. In one embodiment, the fluid logic system can include one or more fluid reservoirs and one or more valves coupled between the fluid reservoir(s) and the restriction device. The valves can be configured to regulate fluid flow between the reservoir(s) and the restriction device. One method for regulating the flow of fluid between the reservoir(s) and the restriction device is to configure the valve(s) to maintain a pressure of fluid in the restriction device within a pre-set pressure range. The pre-set pressure range can include a variety of different types of pressures, but in one exemplary embodiment the range includes a minimum pre-set pressure and a maximum pre-set pressure. When a pressure of fluid in the restriction device is less than the minimum pre-set pressure, the valve(s) can be configured to open to allow fluid flow from the fluid reservoir(s) to the restriction device. When a pressure of fluid in the restriction device is equal to and/or greater than the minimum pre-set pressure, the valve(s) can be configured to close to stop fluid flow from the fluid reservoir(s) to the restriction device. Likewise, when a pressure of fluid in the restriction device is greater than the maximum pre-set pressure, the valve(s) can be configured to open to allow fluid flow from the restriction device to the fluid reservoir(s). When a pressure of fluid in the restriction device is equal to and/or less than the maximum pre-set pressure, the valve(s) can be configured to close to stop fluid flow from the restriction device to the fluid reservoir(s). In one exemplary embodiment, the method can include adjusting the pre-set pressure range, for instance by adjusting a pressure of fluid in the fluid reservoir(s) or by adjusting one or more parameters of the valve(s).
The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.
The present invention generally provides methods and devices for regulating a restriction system. In one exemplary embodiment, as shown in
A person skilled in the art will appreciate that the gastric band can have a variety of other configurations, moreover the various methods and devices disclosed herein have equally applicability to other types of restriction devices. For example, bands are used for the treatment of fecal incontinence, as described in U.S. Pat. No. 6,461,292 which is hereby incorporated herein by reference in its entirety. Bands can also be used to treat urinary incontinence, as described in U.S. Patent Application No. 2003/0105385 which is hereby incorporated herein by reference in its entirety. Bands can also be used to treat heartburn and/or acid reflux, as disclosed in U.S. Pat. No. 6,470,892 which is hereby incorporated herein by reference in its entirety. Bands can also be used to treat impotence, as described in U.S. Patent Application No. 2003/0114729 which is hereby incorporated herein by reference in its entirety.
As further shown in
In one exemplary embodiment, the fluid logic system 30 can have a minimum pre-set pressure limit such that, when the pressure of the fluid in the restriction device drops below the minimum pre-set pressure limit (for example, due to patient weight loss), fluid is released from the fluid reservoir into the restriction device 20 to thereby increase the pressure in the restriction device 20 (thereby increasing the amount of restriction) until the pressure is equal to or greater than the minimum pre-set pressure limit. In such an embodiment, the fluid reservoir is preferably the high pressure fluid reservoir 40, as the high pressure will force fluid to flow into the restriction device 20. Alternatively, or in addition, the fluid logic system 30 can have a maximum pre-set pressure limit such that, when the pressure of the fluid in the restriction device 20 exceeds the maximum pre-set pressure limit (for example, due to a food blockage in the pathway), fluid is released from the restriction device 20 into the fluid reservoir to thereby decrease the pressure in the restriction device 20 (thereby decreasing the amount of restriction) until the pressure is equal to or less than the maximum pre-set pressure limit. In such an embodiment, the fluid reservoir is preferably the low pressure fluid reservoir 50, as the low pressure will allow fluid to flow from the restriction device 20 into the reservoir 50. Having a pre-set pressure limit(s) is particularly advantageous as it allows for small variations in the pressure in the restriction device 20, for example while the patient is eating, without continuously altering the fluid pressure in the restriction device, yet it is effective to maintain the pressure within a desired range to provide an amount of restriction necessary for the device to be effective.
The maximum pre-set pressure limit and the minimum pre-set pressure limit can be defined based on various parameters of the system, and one or both of the limits can be fixed or adjustable. In one exemplary embodiment, the minimum pre-set pressure limit (hereinafter Pmin) is defined by the difference between the fluid pressure in the high pressure fluid reservoir (hereinafter PH) and a first pressure (hereinafter P1) created by a component of the fluid logic system. In other words, Pmin=PH−P1. When the pressure of fluid in the restriction device (hereinafter Pr) is less than Pmin, the fluid logic system will allow fluid flow from the high pressure fluid reservoir to the restriction device. Conversely, when Pr is less than or equal to Pmin, the fluid logic system will prevent fluid flow from the high pressure fluid reservoir to the restriction device. In another exemplary embodiment, the maximum pre-set pressure limit (hereinafter Pmax) is defined by the sum of the fluid pressure in the low pressure fluid reservoir (hereinafter PL) and a second pressure (hereinafter P2) created by a component of the fluid logic system. In other words, Pmax=PL+P2. A person skilled in the art will appreciate that P1 and P2 can be different or they can be the same depending on the configuration of the logic system. When the pressure of fluid in the restriction device (hereinafter Pr) is greater than Pmax, the fluid logic system will allow fluid flow from the restriction device into the low pressure fluid reservoir. Conversely, when Pr is less than or equal to Pmax, the fluid logic system will prevent fluid flow from the restriction device into the low pressure fluid reservoir. A person skilled in the art will appreciate that the logic system can be used to control fluid flow from a high pressure fluid reservoir and/or fluid flow into a low pressure fluid reservoir. Moreover, the pre-set pressure limit can be fixed or adjustable on the high pressure side and/or the low pressure side.
The fluid reservoir(s) 40, 50 used with the fluid logic system 30 can have various configurations, and the system 10 can include any number of reservoirs. For example, the fluid reservoir(s) 40, 50 can be in the form of a housing that is coupled to the fluid logic system 30 by a catheter or other connector, or they can be a housing or chamber formed within the system 30. The fluid reservoir(s) 40, 50 could also be the human body. In an exemplary embodiment, as previously indicated, one of the reservoirs is a high pressure fluid reservoir 40 and the other reservoir is a low pressure fluid reservoir 50. The high pressure fluid reservoir 40 can be, for example, a housing that is effective to contain a fluid under a high pressure. The high pressure can be generated using various techniques known in the art, including various techniques disclosed herein and discussed in more detail below. The low pressure fluid reservoir 50 can likewise be a housing that is effective to contain fluid, but in an exemplary embodiment the low pressure fluid reservoir is the patient's body. A catheter or other pathway can extend from the fluid logic system 30 to a location in the body where it is desirable to release fluid.
As indicated above, various fluid logic systems known in the art can be used to regulate a pressure of fluid in a restriction device.
In use, in an initial position, as shown, the second and third ports 136, 138 are closed such that fluid flow is prevented between the second and third ports 136, 138 and the first port 134. The restriction device 120 applies the force FRD to the valve 132, and the biasing mechanism 144 applies the counterforce FS to the valve 132 to maintain the valve 132 at a substantial equilibrium. In this position, the force FRD applied to the valve 132 by the fluid in the restriction device 120 is within the pre-set pressure range, i.e., greater than the minimum pre-set pressure limit and less than the maximum pre-set pressure limit. When the pressure in the restriction device 120 changes, the valve 132 will move in response. For example, when the pressure of fluid in the restriction device 120 decreases below the minimum pre-set pressure limit, such as due to patient weight loss, the biasing force FS of the biasing mechanism 144 will be greater than the force FRD applied to the valve 132 by the fluid in the restriction device 120, and thus the valve 132 will move to the left. As a result, the valve 132 will move to a first opened position, in which a fluid pathway 156 is formed between the first port 134 and the second port 136. This will allow fluid to flow from the high pressure fluid reservoir 140 into the restriction device 120, thus increasing a pressure of fluid in the restriction device 120. As the pressure increases, the force FRD applied to the valve 132 by the fluid in the restriction device 120 will overcome the biasing force FS to move the valve 132 back toward the right. When the force FRD applied to the valve 132 by the fluid in the restriction device 120 reaches or exceeds the minimum pre-set pressure limit, the valve 132 will return to the initial position, thus preventing any further fluid flow from the high pressure fluid reservoir 140 into the restriction device 120. Conversely, when the pressure of fluid in the restriction device 120 increases to an amount greater than the maximum pre-set pressure limit, for example when a patient is eating, the force FRD applied to the valve 132 by the fluid in the restriction device 120 will be greater than the biasing force FS applied by the biasing mechanism 144, and thus the valve 132 will move to the right. As a result, the valve 132 will move to a second opened position, in which a fluid pathway 158 is formed between the first port 134 and the third port 138. This will allow fluid to flow from the restriction device 120 into the low pressure fluid reservoir 150, thus decreasing a pressure of fluid in the restriction device 120. While not shown, a fluid pathway can also optionally be formed between the first port 134 and the second port 136 when the valve 132 is in the second opened position. However, such a pathway would preferably include a one-way valve that would allow fluid to flow into the high pressure fluid reservoir 140 and would prevent fluid flow from the high pressure fluid reservoir 140 into the restriction device 120. As fluid is released from the restriction device 120 and the pressure decreases, the biasing force FS applied to the valve 132 by the biasing mechanism 144 will overcome the force FRD applied to the valve 132 by the fluid in the restriction device 120 to move the valve 132 back toward the left. When the force FRD applied to the valve 132 by the fluid in the restriction device 120 is equal to or less than the maximum pre-set pressure limit, the valve 132 will return to the initial position, thus preventing any further fluid flow from the restriction device 120 into the low pressure fluid reservoir 150.
As further shown in
In use, the biasing mechanism 244 defines the minimum and maximum pre-set pressure limits. The minimum pre-set pressure limit is the pressure at which, when the pressure of the fluid in the restriction device drops below, the piston 248 moves to the first opened position (i.e., moves to the left) to allow fluid to flow from the high pressure fluid reservoir into the restriction device. The maximum pre-set pressure limit is the pressure at which, when the pressure of the fluid in the restriction device rises above, the piston 248 moves to the second opened position (i.e., moves to the right) to allow fluid to flow from the restriction device into the low pressure fluid reservoir.
A person skilled in the art will appreciate that other components of the logic valve 232 can be altered to define the maximum and minimum pressure limits. For example, the geometry of the piston 248 can be adjusted to change the maximum and minimum pressure limits. In the illustrated embodiment, if the third port 238 were to be positioned further to the right, the maximum and minimum pressure limits would then correspond to different lengths of the biasing mechanism 244.
While the housing 446 can include any number of chambers in the illustrated exemplary embodiment the housing 446 includes two chambers 445, 447 in fluid communication with each other. The first chamber 445 can include the first and second ports 434, 436, the seal 454 for the second port 436, and a portion of the bar 456, and the second chamber 457 can include the deflectable beam 452, another portion of the bar 456, and the biasing mechanism 444. An aperture 449, or other means for transferring fluid from one location to another, such as a pipe, can be located between the first and second chamber 445, 447 to allow the fluid to flow between the first and second chambers 445, 447. This allows fluid from the first port 434 (restriction device) to communicate with the beam, thus allowing the beam to respond to changes in fluid pressure from the first port 434 (restriction device).
In order to allow the deflectable beam 452 to respond to a pressure of fluid from the first port 434 (restriction device), and based on that pressure adjust a position of the seal 454, in one exemplary embodiment the deflectable beam 452 can be bistable. The beam 452 can move between a first position, in which the beam 452 is substantially straight, as shown in
As indicated above, a biasing mechanism 444 is coupled to the deflectable beam 452 and, in conjunction with the laminate 453, is effective to bias the deflectable beam 452 into a predictable buckled configuration. This biasing force resulting from the biasing mechanism 444 is preferably applied in a direction approximately opposite to a direction of a force that is applied to the beam 452 by fluid from the first port 434 (restriction device). In particular, because the first port 434 is in fluid communication with both the restriction device and the second chamber 447 (via the first chamber 445 and the aperture 449), and the second chamber 447 is where the deflectable beam 452 is located, the fluid in the restriction device surrounds the beam 452 to apply a force to the deflectable beam 452 to bias the beam 452 to the straight configuration shown in
In use, the biasing mechanism 444 defines the minimum and maximum pre-set pressure limits. As illustrated by
The minimum pre-set pressure limit is the pressure at which, when the pressure of the fluid in the restriction device drops below, the deflectable beam 452 moves from the first straight position to the second buckled position (i.e., buckles in the approximate downward direction) to allow fluid to flow from the second port 436 (high pressure fluid reservoir) to the first port 434 and into the restriction device to increase a pressure of the fluid in the restriction device. In other words, when the pressure PF applied by the force of the fluid from the restriction device drops below the pressure PSET applied by the force of the biasing mechanism 444, the beam 452 buckles. Buckling movement of the deflectable beam 452 in the approximate downward direction causes the bar 456 and the seal 454 coupled thereto to move in the approximate downward direction, thus opening the port 436 (high pressure fluid reservoir). Fluid flow from the high pressure reservoir into the restriction device will increase a pressure of the fluid in the restriction device. Once the pressure of the fluid of the restriction device is equal to or greater than the minimum pre-set pressure limit, the forces applied to the deflectable beam 452 by the fluid acting thereon from the restriction device will cause the beam 452 to straighten back to the first position. In other words, once the pressure PF applied by the force of the fluid from the restriction device is equal to or greater than the pressure PSET applied by the force of the biasing mechanism 444, the beam 452 will straighten. As a result, the bar 456 will be pulled upward, thus moving the seal 454 to the closed position, thereby preventing the flow of fluid through the second port 436 (high pressure fluid reservoir).
The regulator valve 432 can also have a maximum pre-set pressure limit that can be controlled by way of a valve disposed between a low-pressure fluid reservoir and the restriction device. Although many different types of valves can be used, including the valves disclosed herein, in an exemplary embodiment the valve is a check valve. The check valve can be configured to open to evacuate fluid from the restriction device when the maximum pre-set pressure limit is exceeded. Once the pressure of the fluid of the restriction device is less than or equal to the maximum pre-set pressure, the check valve can be closed.
A person skilled in the art will appreciate that other embodiments of a regulator valve like the regulator valve 432 can include multiple reservoirs, including a low-pressure reservoir, more than two ports, multiple seals, multiple beams, and multiple transfer mechanisms to translate movement of one or more beams to one or more seals. Similarly, in other embodiments a deflectable beam can be adapted to move between more than two positions. For example, a deflectable beam can include a construction that allows it to be adapted to deflect in an approximate upward direction. A person skilled in the art will likewise appreciate that such a design implanting bistable beam elements can be implemented using microelectricalmechanical systems (MEMS) or thin film manufacturing techniques.
Various techniques can be used to form the high pressure fluid reservoir 540, but in one embodiment, as shown, the fluid reservoir 540 can include a spring 542 coupled to a piston 541 such that the spring-piston combination provides a force FSP to pressurize the fluid in the reservoir 540. In one embodiment the spring 542 can be a compression spring. A first port 534 can be located at a terminal end of the fluid reservoir 540 and can be in communication with a restriction device. Fluid flow between the fluid reservoir 540 and the restriction device can be controlled by the gate 548, which as illustrated is at least partially disposed in the fluid reservoir 540.
The gate 548 can have a variety of shapes and sizes that allow it to be configured to move in the fluid reservoir 540 and the chamber 546 of the regulator valve 532 to regulate the flow of fluid from the fluid reservoir 540 to the restriction device. In an exemplary embodiment, the gate 548 is configured to move between an opened position (not shown), in which fluid in the fluid reservoir 540 is free to flow through the first port 534 and into the restriction device, and a closed position (illustrated in
In order to allow movement of the gate 548 between the opened and closed positions, a biasing mechanism 544 can be coupled to the gate 548 and can be effective to bias the gate 548 to one of the opened and closed positions. While the biasing mechanism 544 can be a variety of mechanisms capable of biasing the gate 548 toward the opened or closed position, in the illustrated embodiment the biasing mechanism 544 is a tension spring that provides a force FS to biases the gate 548 toward the opened position (to the right as shown). In order to counteract this force, a second port 536 can be located in a sidewall of the chamber 546 and it can be in fluid communication with the restriction device. The second port 536 allows fluid in the restriction device to apply a force FRD to the gate 548 that is operable to counteract the force FS, and thus biases the gate 548 toward the closed position (to the left as shown).
In use, the biasing mechanism 544 defines the minimum pre-set pressure limit. The minimum pre-set pressure limit is the pressure at which, when the pressure of the fluid in the restriction device drops below, the gate 548 moves to the opened position (i.e., moves to the right) to allow fluid to flow from the high pressure fluid reservoir 540, through the first port 534, and into the restriction device. This movement occurs because the pressure exerted by the force FS of the biasing mechanism 544 exceeds the pressure of the force FRD of the fluid of the restriction device, and thus the pressure from the force FS of the biasing mechanism 544 can move the gate 548 toward the opened position to allow fluid to flow into the restriction device to increase the pressure. Once the pressure of the fluid in the restriction device is equal to or greater than then minimum pre-set pressure, the gate 548 can move to the closed position (i.e., moves to the left) to restrict further flow of fluid from the fluid reservoir 540, through the first port 534, and into the restriction device. This movement occurs because the force FS of the biasing mechanism 544 no longer exceeds the force FRD of the fluid of the restriction device, and thus the force FRD of the fluid in the restriction device pushes the gate 548 toward the closed position. In a preferred embodiment, the effect of the pressure from the fluid reservoir 540 on the gate 548 is negligible when compared to the effect of the pressure from the fluid from the restriction device and/or the biasing mechanism 544 on the gate 548.
The regulator valve 532 can also have a maximum pre-set pressure limit that can be controlled by way of a valve disposed between a low-pressure fluid reservoir and the restriction device and/or the chamber 546. Although many different types of valves can be used, including the valves disclosed herein, in an exemplary embodiment the valve is a check valve. The check valve can be configured to open to evacuate fluid from the restriction device when the maximum pre-set pressure limit is exceeded. Once the pressure of the fluid of the restriction device is less than or equal to the maximum pre-set pressure, the check valve can be closed.
As further shown in
In yet another aspect, the fluid logic system can utilize a check valve.
The biasing mechanism 744 can include any number of components configured to bias the plug 734 in a desired direction, but in the illustrated embodiment the biasing mechanism 744 is a spring coupled to the plug 734 at one end of the spring and to a force-receiving plate 746 at a second end of the spring. The force-receiving plate 746 can have various configurations that allow the force created by the fluid from the fluid reservoir 740 to be transferred to the proximal end 734p of the plug 734. Additionally, the biasing mechanism 744 can be removable and/or adjustable to change the amount of force acting on the plug 734. Changing the amount of force exerted by the biasing mechanism 744 on the plug 734 allows a pre-set pressure limit, for example a minimum pre-set pressure and/or a maximum pre-set pressure, to be adjusted for the check valve 732. As the pre-set pressure limits are adjusted, the plug 734 can be set to move to the opened and closed position at different desired pre-set pressures. When the biasing mechanism is a spring, the pre-set pressure limit can be changed by changing the type of spring that is used, which can at least change the spring constant, and/or changing the length of the spring that is used. An exemplary technique for changing the length of the biasing mechanism 744 when the check valve 732 is already implanted is illustrated in
In addition to changing the pre-set pressure limit(s) or cracking pressure(s) of the check valve 732 to affect the point at which the check valve 732 opens and closes, another way to affect the point at which the check valve 732 opens and closes is to change the pressure of the fluid flowing from the reservoir 740 to the check valve 732. For example, while in the illustrated embodiments the pressure of the fluid in the fluid reservoir 740 may decrease as the check valve 732 opens and closes, in another embodiment the fluid reservoir can be a constant pressure reservoir such that the pressure of the fluid in the reservoir remains substantially constant during and after the opening and closing of the check valve 732. Alternatively, the fluid reservoir can be coupled to a constant pressure reservoir such that, even though the fluid reservoir does not maintain a constant pressure on its own, the constant pressure reservoir is capable of maintaining a constant pressure in the fluid reservoir.
A person having ordinary skill in the art will recognize that even though
The gasket magnet 848 and the set-point magnet 849 can be configured in a number of ways to control the flow of fluid between the first port 834 (fluid reservoir) and the second port 836 (restriction device). As illustrated, the magnets 848, 849 can be disposed in the chamber 846 with opposing poles facing each other, thus repelling each other, and can be adapted to slide therein. In an exemplary embodiment, the gasket magnet 848 is slidable to open and close the first port 834 (fluid reservoir) and thus can have a seal 854 coupled to a left side thereof. The gasket magnet 848 can be effective to move between a closed position, in which the seal 854 occludes the first port 834 to prevent fluid from the fluid reservoir from flowing into the chamber 846 or the restriction device, and an opened position, in which the seal 854 is spaced apart from the first port 834 to allow fluid from the fluid reservoir to flow through the first port 834, into the chamber 846, and then into the second port 836 (restriction device). In alternative embodiments, the gasket magnet 848 itself can serve as the seal. While a location of the gasket magnet 848 can change as a result of sliding between the opened and closed positions, generally the gasket magnet 848 is located between the first and second ports 834, 836. Further, the gasket magnet 848 is preferably sized and shaped to allow fluid to flow between the fluid reservoir and the restriction device. In particular, as shown, the gasket magnet 848 is sized to be smaller than the chamber 846 so that a pathway allows the fluid to travel from the first port 834 (fluid reservoir) to the second port 836 (restriction device). Although in the illustrated embodiment the pathway is disposed below the gasket magnet 848, the pathway can be disposed above or even through the gasket magnet 848.
While the gasket magnet 848 slides between closed and opened positions, the set-point magnet 849 can remain in a fixed position. The fixed position of the set-point magnet 849 can, however, be slidably adjustable to adjust the pre-set pressure limits, as discussed in more detail below. Even though the set-point magnet 849 can be slidably adjustable, the set-point magnet 849 preferably remains spaced apart from the gasket magnet 848 and located to the right of the second port 836. Unlike the gasket magnet 848, the set-point magnet can be sized and shaped to prevent fluid from flowing from one side of the magnet 849 to the other. In particular, as shown, the set-point magnet 849 is sized to generally fit between two sidewalls of the chamber 846. Alternatively, rather than sizing and/or shaping the set-point magnet 849 to prevent the flow of fluid from one side of the set-point magnet 849 to the other, a force-receiving plate configured to both translate a biasing force discussed in more detail below to the set-point magnet 849 and prevent the flow of fluid from one side of the set-point magnet 849 to the other can be coupled to the right side of the set-point magnet 849.
Various forces can act on each of the gasket magnet 848 and the set-point magnet 849 to assist with the control of fluid flow from the first port 834 (fluid reservoir) to the second port 836. In the illustrated embodiment, because the magnets 848, 849 have opposing poles facing each other, a force FSM to the left acts on the gasket magnet 848 and a force FGM to the right acts on the set-point magnet 849. The gasket magnet 848 can also have at least two additional forces acting on it: a force FFR from the fluid of the fluid reservoir and a force FRD from the fluid from the restriction device. The force FRD from the fluid of the restriction device can also act on the set-point magnet 849.
In use, the set-point magnet 849 defines the minimum pre-set pressure limit. The minimum pre-set pressure limit is the pressure at which, when the pressure of the fluid in the restriction device drops below, the gasket magnet 848 moves to the opened position (i.e., moves to the right) to allow fluid to flow from the first port 834 (fluid reservoir), through the second port 836, and into the restriction device. This movement occurs because the pressure exerted by the force FFR of the fluid reservoir exceeds the pressure of the combined forces FRD of the fluid of the restriction device and FSM of the set-point magnet 849, and thus the pressure from the force FFR of the fluid reservoir can move the gasket magnet 848 toward the opened position to allow the pressure of the fluid of the restriction device to increase. Once the pressure of the fluid of the restriction device is equal to or greater than the minimum pre-set pressure, the gasket magnet 848 can move to the closed position (i.e., moves to the left) to restrict further flow of fluid from the first port 834 (fluid reservoir), through the second port 836, and into the restriction device. This movement occurs because the pressure resulting from the force FFR of the fluid reservoir no longer exceeds the pressure of the combine forces FRD of the fluid of the restriction device and FSM of the set-point magnet 849, and thus the pressure from the combined forces FRD of the fluid of the restriction device and FSM of the set-point magnet 849 push the gasket magnet 848 toward the closed position.
The check valve 832 can also have a maximum pre-set pressure limit that can be controlled by way of a second valve disposed between a low-pressure fluid reservoir and the restriction device and/or the chamber 846. Although many different types of valves can be used, including the valves disclosed herein, in an exemplary embodiment the second valve is a second check valve. The second check valve can be configured to open to evacuate fluid from the restriction device when the maximum pre-set pressure limit is exceeded. Once the pressure of the fluid of the restriction device is less than or equal to the maximum pre-set pressure, the second check valve can be closed.
In another embodiment, the force FSM of the set-point magnet 849 can be adjustable. Adjusting the force FSM of the set-point magnet 849 can likewise adjust the pre-set pressure limit because of the effect of the force FSM of the set-point magnet 849 on the gasket magnet 848. Generally, the closer the set-point magnet 849 is to the gasket magnet 848, the greater the force FSM is that acts on the gasket magnet 848. One way to change the amount of force acting on the gasket magnet 848 is to change various properties of either or both of the gasket and set-point magnets 848, 849 themselves by, for example, using a different material or adjusting the size. In the illustrated embodiment, the force FSM of the set-point magnet 849 can be adjusted by a biasing mechanism. As shown, the biasing mechanism is a fluid disposed to the right of the set-point magnet 849. The chamber 846 can include a third port 838 formed in a second end of the chamber 846 and configured to receive a fluid. The fluid can generally be incompressible. Adjustment of an amount or type of fluid in the chamber 846 to the right of the set-point magnet 849 can subsequently adjust a position of the set-point magnet 849. For example, in the illustrated embodiment, adding fluid via the third port 838 increases a force FF applied to the set-point magnet 849 acting to the left as illustrated, which in turn causes the set-point magnet 849 to move closer to the gasket magnet 848. Moving the set-point magnet 849 close to the gasket magnet 848 subsequently increases the force FSM acting on the gasket magnet 848. Further, biasing mechanisms such as expandable bladders, springs, and screws, as discussed with respect to other embodiments, can also be incorporated into the design of the check valve 832 to adjust the pre-set pressure of the system. Likewise, similar to the other described check valve system, the pressure of the fluid in the fluid reservoir can also be adjusted, or made constant, to adjust the pre-set pressure of the check valve 832.
In another embodiment of a check valve 832′, shown in
The forces created by the parameters related to the set-point magnet 849′ can be adjusted in many of the same ways as discussed with respect to the set-point magnet 849 of
A person having ordinary skill in the art will recognize that even though
As previously indicated, the various fluid logic systems disclosed herein can include a high pressure fluid reservoir and various techniques can be used to generate a high pressure within a fluid reservoir. In fact, as discussed with respect to the magnetic check valves, many of the embodiments and techniques discussed with respect to adjusting and regulating the flow of check valves can also be applied to adjusting and controlling the flow of fluid into and/or out of one or more fluid reservoirs. By way of further non-limiting example,
In the illustrated embodiment of
The housing 942 can have a variety of shapes and sizes, but in the illustrated embodiment the housing 942 is substantially cylindrical. As shown, a first port 952 is formed in a first end of the housing 942 and a second port 954 is formed in a second end thereof. While the ports can be coupled to various components of the system, in an exemplary embodiment the first port 952 is configured to receive one or more chemicals for use in chemical reactions and the second port 954 is in fluid communication with a valve or other component of a restriction system. In some embodiments, depending on the chemical reaction(s) used, the first port can be excluded, for instance if access to the chemical reaction chamber 944 is not needed for the operation of the high pressure fluid reservoir 940. Fluid flow from the fluid chamber 946 to the valve is controlled, at least in part, by chemical reaction(s) performed in the chemical reaction chamber 944. At least a portion of the resulting product of the chemical reaction(s) can adjust a force applied by the expandable bladder 948 to the fluid chamber 946, which in turn adjusts an amount of fluid flowing from the fluid chamber 946 to the valve or other component of a restriction system. In a preferred embodiment, the chemical reaction(s) are reversible, and thus the same fluid chamber 946 can be used to both increase and decrease the rate and/or amount of fluid flowing from the fluid chamber 946 to the valve or other component of a restriction system.
Chemical reaction(s) are generally initiated in one of two ways. In one method, one or more chemicals disposed in the chemical reaction chamber 944 can be selected such that the reaction is not instantaneous and thus the results of the reaction can occur at some point after the introduction of the chemicals into the chemical reaction chamber 944. In another method, one or more chemicals can be added to the chemical reaction chamber 944 through the first port 952 to cause a desired chemical reaction. In an exemplary embodiment, all of the chemicals needed to generate the desired chemical reaction are disposed in the chemical reaction chamber 944 except one, and the last chemical is added via the first port 952 to begin the desired chemical reaction. A person skilled in the art will recognize that any number of chemicals can be used in the chemical reaction chamber 944 and any number can be added to the chemical reaction chamber 944, depending at least in part on the chemical reaction involved and the desired result. The desired chemical reaction can be effective to move the expandable bladder 948, which in turn affects the flow of fluid from the fluid chamber 946 to the valve or other components of a restriction system. For example, the resulting reaction can be an exothermic reaction, which releases heat thus causing the expandable bladder 948 to expand and apply additional force to the fluid in the fluid chamber 946. This results in an increase in the amount of fluid flowing out of the fluid chamber 946, which can also increase the amount of force and pressure being applied to the valve or other component of a restriction system, depending on the other components of the system. An example of an exothermic reaction that can work in such an embodiment includes mixing water with strong acids. Similarly, an endothermic reaction, which absorbs heat, can also be used. An endothermic reaction can cause the expandable bladder 948 to contract and thus apply less force to the fluid in the fluid chamber 946 than before the endothermic reaction, which in turn results in a decrease of the amount of fluid flowing out of the fluid chamber 946, or alternatively causes fluid to flow into the chamber 946. An endothermic reaction can also decrease the amount of force and pressure being applied to the valve or other component of a restriction system coupled to the second port 954. Chemical reactions are not limited to just exothermic and endothermic reactions however. Many other types of reactions can also be used to increase or decrease an amount of force applied to fluid disposed in the fluid chamber 946. Often times these reactions can produce by-products, such as gas. The release of gas and other products can cause the pressure within the chemical reaction chamber 944 to increase, which in turn increases a force applied to the expandable bladder 948. One example of a gas releasing reaction that can be used is NaHCO3+HCL→NaCl+H20+CO2. A second example of a gas releasing reaction that can be used is a combination of XCO3 and an acid.
The embodiment shown in
Each of the ports 952′, 954′, 956′ can be coupled to various components of the system, but in the illustrated embodiment the second port 954′ is in fluid communication with a valve or other component of a restriction system such that fluid from the fluid chamber 946′ can move between the fluid chamber 946′ and the valve or other components of the restriction system. Further, the first port 952′ is configured to receive one or more chemicals for use in chemical reactions in the first chemical reaction chamber 944′ and the third port 956′ is configured to receive one or more chemicals for use in chemical reactions in the second chemical reaction chamber 945′. Optionally, a gate 951′ can be disposed between the first and second chemical reaction chambers 944′, 945′ to allow for communication between the chambers 944′, 945′ and/or the ports 952′, 956′. In some embodiments, depending on the chemical reaction(s) used, the first and third ports 952′, 956′ can be excluded, for instance if access to the chemical reaction chambers 944′, 945′ is not needed for the operation of the high pressure fluid reservoir 940′. Further, in an exemplary embodiment, each chemical reaction chamber 944′, 945′ can be configured for a different type of reaction. For example, in instances where an exothermic reaction is used to expand the expandable bladder 948′ and an endothermic reaction is used to contract the expandable bladder 948′, the first chemical reaction chamber 944′ can be configured for exothermic reactions and the second chemical reaction chamber 945′ can be configured for endothermic reactions. This embodiment is advantageous because non-reversible chemical reactions can be easily used in the chemical reaction chambers 944′, 945′. Use of the high pressure fluid reservoir 940′ is similar to use of the high pressure fluid reservoir 940 illustrated in
A person skilled in the art will recognize that although the teachings related to the embodiments in
To the extent that any of the fluid logic systems, high pressure fluid reservoirs, other devices and systems, and/or components thereof incorporate springs or other mechanical components that can be adjusted to provide different dimensions or properties (such as spring constants), a person skilled in the art will appreciate that changes to many of the properties and dimensions will affect the performance of the respective fluid logic systems, high pressure fluid reservoirs, other devices and systems, and/or components thereof. Accordingly, even if changes to these types of components are not discussed above, such changes could be incorporated into many of the fluid logic systems, high pressure fluid reservoirs, other devices and systems, and/or components thereof to affect the desired performance of each.
A person skilled in the art will appreciate that the present invention has application in conventional endoscopic and open surgical instrumentation as well application in robotic-assisted surgery.
The devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the device can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the device can be disassembled, and any number of the particular pieces or parts of the device can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the device can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application.
Preferably, the invention described herein will be processed before surgery. First, a new or used instrument is obtained and if necessary cleaned. The instrument can then be sterilized. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK bag. The container and instrument are then placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation kills bacteria on the instrument and in the container. The sterilized instrument can then be stored in the sterile container. The sealed container keeps the instrument sterile until it is opened in the medical facility.
It is preferred that device is sterilized. This can be done by any number of ways known to those skilled in the art including beta or gamma radiation, ethylene oxide, steam.
One skilled in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the invention is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.
