Patent Application
20090173351
Snoring is very common among mammals including humans. Snoring is a noise produced while breathing during sleep due to the vibration of the soft palate and uvula. Not all snoring is bad, except it bothers the bed partner or others near the person who is snoring. If the snoring gets worst overtime and goes untreated, it could lead to apnea.
Those with apnea stop breathing in their sleep, often hundreds of times during the night. Usually apnea occurs when the throat muscles and tongue relax during sleep and partially block the opening of the airway. When the muscles of the soft palate at the base of the tongue and the uvula relax and sag, the airway becomes blocked, making breathing labored and noisy and even stopping it altogether. Sleep apnea also can occur in obese people when an excess amount of tissue in the airway causes it to be narrowed.
In a given night, the number of involuntary breathing pauses or “apneic events” may be as high as 20 to 60 or more per hour. These breathing pauses are almost always accompanied by snoring between apnea episodes. Sleep apnea can also be characterized by choking sensations.
Sleep apnea is diagnosed and treated by primary care physicians, pulmonologists, neurologists, or other physicians with specialty training in sleep disorders. Diagnosis of sleep apnea is not simple because there can be many different reasons for disturbed sleep.
The specific therapy for sleep apnea is tailored to the individual patient based on medical history, physical examination, and the results of polysomnography. Medications are generally not effective in the treatment of sleep apnea. Oxygen is sometimes used in patients with central apnea caused by heart failure. It is not used to treat obstructive sleep apnea.
Continuous positive airway pressure (CPAP) is the most common treatment for sleep apnea. In this procedure, the patient wears a mask over the nose or mouth during sleep, and pressure from an air blower forces air through the air passages. The air pressure is adjusted so that it is just enough to prevent the throat from collapsing during sleep. The pressure is constant and continuous. CPAP prevents airway closure while in use, but apnea episodes return when CPAP is stopped or it is used improperly. Many variations of CPAP devices are available and all have the same side effects such as nasal irritation and drying, facial skin irritation, abdominal bloating, mask leaks, sore eyes, and headaches. Some versions of CPAP devices vary the pressure to coincide with the person's breathing pattern, and other CPAP devices start with low pressure, slowly increasing it to allow the person to fall asleep before the full prescribed pressure is applied.
Dental appliances that reposition the lower jaw and the tongue have been helpful to some patients with mild to moderate sleep apnea or who snore but do not have apnea. A dentist or orthodontist is often the one to fit the patient with such a device.
Some patients with sleep apnea may need surgery. Although several surgical procedures are used to increase the size of the airway, none of them is completely successful or without risks. More than one procedure may need to be tried before the patient realizes any benefits. Some of the more common procedures include removal of adenoids and tonsils (especially in children), nasal polyps or other growths, or other tissue in the airway and correction of structural deformities. Younger patients seem to benefit from these surgical procedures more than older patients.
Uvulopalatopharyngoplasty (UPPP) is a procedure used to remove excess tissue at the back of the throat (tonsils, uvula, and part of the soft palate). The success of this technique may range from 30 to 60 percent. The long-term side effects and benefits are not known, and it is difficult to predict which patients will do well with this procedure.
Laser-assisted uvulopalatoplasty (LAUP) is done to eliminate snoring but has not been shown to be effective in treating sleep apnea. This procedure involves using a laser device to eliminate tissue in the back of the throat. Like UPPP, LAUP may decrease or eliminate snoring but not eliminate sleep apnea itself. Elimination of snoring, the primary symptom of sleep apnea, without influencing the condition may carry the risk of delaying the diagnosis and possible treatment of sleep apnea in patients who elect to have LAUP. To identify possible underlying sleep apnea, sleep studies are usually required before LAUP is performed.
Somnoplasty is a procedure that uses RF to reduce the size of some airway structures such as the uvula and the back of the tongue. This technique helps in reducing snoring and is being investigated as a treatment for apnea.
Tracheostomy is used in persons with severe, life-threatening sleep apnea. In this procedure, a small hole is made in the windpipe and a tube is inserted into the opening. This tube stays closed during waking hours and the person breathes and speaks normally. It is opened for sleep so that air flows directly into the lungs, bypassing any upper airway obstruction. Although this procedure is highly effective, it is an extreme measure that is rarely used.
Patients in whom sleep apnea is due to deformities of the lower jaw may benefit from surgical reconstruction. Surgical procedures to treat obesity are sometimes recommended for sleep apnea patients who are morbidly obese. Behavioral changes are an important part of the treatment program, and in mild cases behavioral therapy may be all that is needed. Overweight persons can benefit from losing weight. Even a 10 percent weight loss can reduce the number of apneic events for most patients. Individuals with apnea should avoid the use of alcohol and sleeping pills, which make the airway more likely to collapse during sleep and prolong the apneic periods. In some patients with mild sleep apnea, breathing pauses occur only when they sleep on their backs. In such cases, using pillows and other devices that help them sleep in a side position may be helpful.
Recently, Restore Medical, Inc., Saint Paul, Minn. has developed a new treatment for snoring and apnea, called the Pillar technique. Pillar System involves a procedure where 3 or more small polyester rod devices are placed in the patient's soft palate. The Pillar System stiffens the palate, reduces vibration of the tissue, and prevents the possible airway collapse. Stiff implants in the soft palate, however, could hinder patient's normal functions like speech, ability to swallow, coughing and sneezing. Protrusion of the implant into the airway is another long-term concern.
As the current treatments for snoring and/or apnea are not effective and have side-effects, there is a need for additional treatment options.
A tongue implant control system and methods for stabilizing the tongue are disclosed. The tongue implant control system includes an implant device and a non-implanted control device in wireless communication. The control device provides an inductive power transfer for operating the implant device. The control device also sends commands for changing a state of the implant device. The implant device includes a flexible portion for attachment to the tongue and to one or more actuators. The one or more actuators may include shape memory material. The implant device detects a command from the control device and powers an actuator based on the command. Optionally, the implant device communicates its operating state to the control device and the control device displays information about the implant device at a user interface.
In one embodiment, a tongue implant device is disclosed. The implant device includes a flexible portion for attachment to the tongue. The flexible portion has three-dimensional flexibility in a first state and lesser three-dimensional flexibility in a second state. A first actuator is coupled to the flexible portion and configured to change the state of the flexible portion in response to a first control signal. A transducer is configured to wirelessly receive a power transfer signal and to provide a supply voltage to the implant device. A processor is configured to couple with the transducer and the first actuator. The processor is operative in response to the supply voltage and generates the first control signal based on the power transfer signal. The processor can generate the first control signal based on an amplitude of the power transfer signal, a frequency of the power transfer signal, or a combination of both amplitude and frequency. The first actuator can include shape memory material such as a Nitinol coil. In some embodiments, the first actuator includes a linear motor.
In another embodiment, the implant device includes a second actuator coupled to the processor. The second actuator maintains the flexible portion in the second state and can include a latch mechanism. The second actuator enables a transition from the second state to the first state in response to a second control signal from the processor. In some embodiments, the processor can be configured to generate the first control signal in response to a first frequency of the power transfer signal and to generate the second control signal in response to a second frequency of the power transfer signal. The processor can also be configured to generate the first and second control signals in response to first and second amplitude modulations of the power transfer signal, respectively.
In additional embodiments, the processor can be configured to communicate with an external device by pulsing the first control signal for a predetermined time that is less than a time required to change the flexible portion from the first state to the second state. The processor can communicate an IDLE message by pulsing the first control signal for a first predetermined time and an ACK message by pulsing the first control signal for a second predetermined time.
In one embodiment, a device for controlling a tongue stabilizing implant is disclosed. The device includes a user interface configured to receive a command for controlling the implant and a processor coupled to the user interface. The processor is configured to generate a control signal in response to the command. The device includes a transducer configured to generate an electromagnetic field based on the control signal. A communication circuit is coupled to the processor and the transducer. The communication circuit is configured to detect a message from the implant based on a state of the transducer and to communicate the message to the processor. In some embodiments, the processor is configured to update the user interface based on the message from the communication circuit.
In a further embodiment, the device for controlling the tongue implant includes an oscillator coupled to the transducer and the processor. The oscillator can be configured to provide a reference signal for driving the transducer such that the oscillator and the transducer self-oscillate at a resonant frequency of the transducer. The resonant frequency can be changed. For example, by changing a capacitance of the transducer, a frequency modulation of the electromagnetic field can be achieved.
In other embodiments, the device may include a programmable power supply. The programmable power supply can be coupled with the transducer and the processor and configured to provide a voltage signal to the transducer for determining an amplitude of the electromagnetic field. The voltage signal can be determined based on the control signal.
In one embodiment, a method of stabilizing the tongue is disclosed. The method includes receiving an electromagnetic signal wirelessly at an implant device attached to the tongue and producing a supply voltage from the electromagnetic signal. The method includes detecting an amplitude modulation of the electromagnetic signal and performing a first operation to limit a flexibility of the implant device in response to detecting a first amplitude of the electromagnetic signal. The method also includes performing a second operation to restore the flexibility of the implant device in response to detecting a second amplitude of the electromagnetic signal. Performing the first and second operation is based upon availability of the supply voltage.
In one embodiment, a system for stabilizing the tongue is disclosed. The system includes an implant device and a non-implanted control device. The implant device includes a flexible portion for attachment with the tongue having three-dimensional flexibility in a first state and lesser three-dimensional flexibility in a second state. A first actuator coupled to the flexible portion is configured to change the state of the flexible portion from the first state to the second state in response to a first control signal. A second actuator coupled to the flexible portion is configured to permit the flexible portion to transition from the second state to the first state in response to a second control signal. The implant device also includes a transducer configured to wirelessly receive an electromagnetic signal and to provide a supply voltage. A processor is coupled to the transducer. The processor receives the supply voltage and is configured to generate the first or second control signal based upon a command that is detected based on the electromagnetic signal. The non-implanted portion includes a transmit circuit configured to generate the electromagnetic signal and a second processor. The second processor can be configured to control operation of the transmit circuit and to determine the amplitude of the electromagnetic signal.
A first aspect of the invention is a device for the treatment of disorders associated with improper airway patency, such as snoring or sleep apnea. The device comprises of a deformable element to adjust the opening of the airway. In a preferred embodiment, the deformable element comprises of an electroactive polymer (EAP) element. The electroactive polymer element in the device assists in maintaining appropriate airway opening to treat the disorders. Typically, the EAP element provides support for the walls of an airway, when the walls collapse, and thus, completely or partially opens the airway.
The device functions by maintaining energized and non-energized configurations of the EAP element. In preferred embodiments, during sleep, the EAP element is energized with electricity to change its shape and thus modify the opening of the airway. Typically, in the non-energized configuration the EAP element is soft and in the energized configuration is stiffer. The EAP element of the device can have a pre-set non-energized configuration wherein it is substantially similar to the geometry of the patient's airway where the device is implanted.
In some embodiments, the device, in addition to the EAP element, includes an implantable transducer in electrical communication with the EAP element. A conductive lead connects the EAP element and the implantable transducer to the each other. The device of the present invention typically includes a power supply in electrical communication with the EAP element and/or the implantable transducer, such as a battery or a capacitor. The battery can be disposable or rechargeable.
Preferred embodiments of the invention include a non-implanted portion, such as a mouthpiece, to control the implanted EAP element. The mouthpiece is typically in conductive or inductive communication with an implantable transducer. In one embodiment, the mouthpiece is a dental retainer with an induction coil and a power source. The dental retainer can further comprise a pulse-width-modulation circuit. When a dental retainer is used it is preferably custom fit for the individual biological subject. If the implantable transducer is in inductive communication, it will typically include an inductive receiver, such as a coil. The implantable transducer can also include a conductive receiver, such as a dental filling, a dental implant, an implant in the oral cavity, an implant in the head or neck region. In one embodiment, the device includes a dermal patch with a coil, circuit and power source, in communication with the implantable transducer. The dermal patch can also include a pulse-width-modulation circuit.
Another aspect of the invention is a method to modulate air flow through airway passages. Such modulation is used in the treatment of diseases such as snoring and sleep apnea. One method of the invention is a method for modulating the airflow in airway passages by implanting in a patient a device comprising a deformable element and controlling the device by energizing the deformable element. The deformable element preferably comprises an electroactive polymer element. The deformable element can be controlled with a mouthpiece inserted into the mouth of the patient. The energizing is typically performed with the use of a power supply in electrical communication, either inductive communication or conductive communication, with the deformable element. A transducer can be used to energize the deformable element by placing it in electrical communication with the power supply. Depending on the condition being treated, the deformable element is placed in different locations such as soft palate, airway sidewall, uvula, pharynx wall, trachea wall, larynx wall, and/or nasal passage wall.
A preferred embodiment of the device of the present invention comprises an implantable deformable element; an implantable transducer; an implantable lead wire connecting the deformable element and the transducer; a removable transducer; and a removable power source; and wherein the deformable element comprises an electroactive polymer.
Electroactive polymer is a type of polymer that responds to electrical stimulation by physical deformation, change in tensile properties, and/or change in hardness. There are several types of electroactive polymers like dielectric electrostrictive polymer, ion exchange polymer and ion exchange polymer metal composite (IPMC). The particular type of EAP used in the making of the disclosed device can be any of the aforementioned electroactive polymers.
Suitable materials for the electroactive polymer element include, but are not limited to, an ion exchange polymer, an ion exchange polymer metal composite, an ionomer base material. In some embodiments, the electroactive polymer is perfluorinated polymer such as polytetrafluoroethylene, polyfluorosulfonic acid, perfluorosulfonate, and polyvinylidene fluoride. Other suitable polymers include polyethylene, polypropylene, polystyrene, polyaniline, polyacrylonitrile, cellophane, cellulose, regenerated cellulose, cellulose acetate, polysulfone, polyurethane, polyvinyl alcohol, polyvinyl acetate, polyvinyl pyrrolidone. Typically, the electroactive polymer element includes a biocompatible conductive material such as platinum, gold, silver, palladium, copper, and/or carbon.
Suitable shapes of the electroactive polymer element include three dimensional shape, substantially rectangular, substantially triangular, substantially round, substantially trapezoidal, a flat strip, a rod, a cylindrical tube, an arch with uniform thickness or varying thickness, a shape with slots that are perpendicular to the axis, slots that are parallel to the longitudinal axis, a coil, perforations, and/or slots.
IPMC is a polymer and metal composite that uses an ionomer as the base material. Ionomers are types of polymers that allow for ion movement through the membrane. There are several ionomers available in the market and some of the suited ionomers for this application are polyethylene, polystyrene, polytetrafluoroethylene, polyvinylidene fluoride, polyfluorosulfonic acid based membranes like NAFION® (from E. I. Du Pont de Nemours and Company, Wilmington, Del.), polyaniline, polyacrylonitrile, cellulose, cellulose acetates, regenerated cellulose, polysulfone, polyurethane, or combinations thereof. A conductive metal, for example gold, silver, platinum, palladium, copper, carbon, or combinations thereof, can be deposited on the ionomer to make the IPMC. The IPMC element can be formed into many shapes, for example, a strip, rod, cylindrical tube, rectangular piece, triangular piece, trapezoidal shape, arch shapes, coil shapes, or combinations thereof. The IPMC element can have perforations or slots cut in them to allow tissue in growth.
The electroactive polymer element has, in some embodiments, multiple layers of the electroactive polymer with or without an insulation layer separating the layers of the electroactive polymer. Suitable insulation layers include, but are not limited to, silicone, polyurethane, polyimide, nylon, polyester, polymethylmethacrylate, polyethylmethacrylate, neoprene, styrene butadiene styrene, or polyvinyl acetate.
In some embodiments, the deformable element, the entire device, or portions of the airway implant have a coating. The coating isolates the coated device from the body fluids and/or tissue either physically or electrically. The device can be coated to minimize tissue growth or promote tissue growth. Suitable coatings include poly-L-lysine, poly-D-lysine, polyethylene glycol, polypropylene, polyvinyl alcohol, polyvinylidene fluoride, polyvinyl acetate, hyaluronic acid, and/or methylmethacrylate.
Instead of or in addition to wire lead 14, the connecting element may be an inductive energy transfer system, a conductive energy transfer system, a chemical energy transfer system, an acoustic or otherwise vibratory energy transfer system, a nerve or nerve pathway, other biological tissue, or combinations thereof. The connecting element is made from one or more conductive materials, such as copper. The connecting element is completely or partially insulated and/or protected by an insulator, for example polytetrafluoroethylene (PTFE). The insulator can be biocompatible. The power supply 4 is typically in electrical communication with the deformable element 8 through the connecting element. The connecting element is attached to an anode 10 and a cathode 12 on the power supply 4. The connecting elements can be made from one or more sub-elements.
The deformable element 8 is preferably made from an electroactive polymer. Most preferably, the electroactive polymer is an ion exchange polymer metal composite (IPMC). The IPMC has a base polymer embedded, or otherwise appropriately mixed, with a metal. The IPMC base polymer is preferably perfluoronated polymer, polytetrafluoroethylene, polyfluorosulfonic acid, perfluorosulfonate, polyvinylidene fluoride, hydrophilic polyvinylidene fluoride, polyethylene, polypropylene, polystyrene, polyaniline, polyacrylonitrile, cellophane, cellulose, regenerated cellulose, cellulose acetate, polysulfone, polyurethane, polyvinyl alcohol, polyvinyl acetate and polyvinyl pyrrolidone, or combinations thereof. The IPMC metal can be platinum, gold, silver, palladium, copper, carbon, or combinations thereof.
Preferably, the airway implant device 2 discussed herein is used in combination with an inductive coupling system 900 such as depicted in
Two preferred embodiments of the airway implant device are shown in
The implants described herein are preferably implanted with a deployment tool. Typically, the implantation involves an incision, surgical cavitation, and/or affixing the implant.
One embodiment of the invention is an airway implant device with a sensor for monitoring a condition prior to and/or during the occurrence of an apneic event. Preferably, the sensor monitors for blockage of an airway. The sensor senses the possible occurrence of an apneic event. This sensing of a possible apneic event is typically by sensing a decrease in the airway gap, a change in air pressure in the airway, or a change in air flow in the airway. A progressive decrease in the airway gap triggers the occurrence of an apneic event. Most preferably the sensor senses one or more events prior to the occurrence an apneic event and activates the airway implant to prevent the apneic event. In some embodiments, the airway implant device and the sensor are in the same unit. In other embodiments, the deformable element of the airway implant device is the sensor. In these embodiments, the deformable element acts as both a sensor and actuator. In yet other embodiments, the airway implant device and the sensor are in two or more separate units.
One aspect of the invention is an airway implant device with a sensor for sensing the occurrence of apneic events and actuating the device. The invention also includes methods of use of such device.
One embodiment of an airway implant device with sensor is depicted in
In one embodiment, the operation of the device is as follows:
a) A threshold gap is calibrated into the microcontroller which is present in the removable retainer of the device. This threshold gap corresponds to the gap 3803′ formed by the position of the soft palate with respect to the laryngeal wall as depicted in the
b) The non-contact sensor constantly monitors the gap and the information is constantly analyzed by a program present in the microcontroller.
c) The airway implant actuator is in the off state (not powered state) as long as the threshold gap is not reached.
d) When the gap is equal to the threshold gap, the micro controller, powers on the airway implant actuator (on state). This leads to the stiffening of the airway implant actuator, which in-turn stiffens the soft palate.
e) This stiffening of the soft palate prevents the obstruction of the airway and modulates the occurrence of an apneic event.
f) When the gap becomes more than the threshold gap, the micro-controller turns off the airway implant actuator (off state).
Typically, an algorithm in the micro-controller controls the actuation of the actuator. An example of the algorithm is—
Complex algorithms, such as adaptive algorithms, can also be used. The objective of the adaptive algorithm can be to selectively control the stiffness of the soft palate by varying the power applied to the airway implant actuator.
Another example of an algorithm to selectively control the stiffness of the soft palate is:
An example of a controller to maintain a predetermined reference gap is shown is
In alternative embodiments, the sensor can be a wall tension sensor, an air pressure sensor, or an air flow monitoring sensor. In another embodiment, instead of fully turning the airway implant actuator on or off, the actual value of the airway gap can be used to selectively apply varying voltage to the airway implant actuator, hence selectively varying the stiffness of the soft palate. In yet another embodiment, if the airway implant actuator exhibits a lack of force retention over an extended period of time under DC voltage, a feedback control algorithm may be implemented in the microcontroller, which uses the sensory information provided by the sensors to control the stiffness of the soft palate by maintaining the force developed by the airway implant actuator.
Another embodiment of the invention is depicted in
Some of the advantages of the use of an airway sensor with an airway implant device include: optimization of the power consumed by the airway implant device and hence extension of the life of the device; assistance in predicting the occurrence of apneic event, and hence selective activation of the device in order to minimize any patient discomfort; flexibility to use a feedback control system if required to compensate for any actuator irregularities; and possible configuration of the system to interact with an online data management system which will store different parameters related to apneic events for a patient. This system can be accessed by the doctor, other health care providers, and the insurance agency which will help them provide better diagnosis and understanding of the patient's condition.
In preferred embodiments, the airway gap is individually calculated and calibrated for each patient. This information can be stored in the microcontroller. The sensors are described herein mainly in the context of airway implant devices comprising of electroactive polymer actuators. The sensors can also be used with airway implant devices comprising other active actuators, i.e., actuators that can be turned on, off, or otherwise be controlled, such as magnets. The sensors can be used to activate, in-activate, and/or modulate magnets used in airway implant devices. Preferably, the sensors are in the form of a strip, but can be any other suitable shape for implantation. They are typically deployed with a needle with the help of a syringe. The sensor can be made with any suitable material. In preferred embodiments, the sensor is a smart material, such as an IPMC. The sensor is typically in connection with a microcontroller, which is preferably located in the retainer. This connection can be either physical or wireless.
Suitable sensors include, but are not limited to, an electroactive polymer like ionic polymer metal composite (IPMC). Suitable materials for IPMC include perfluorinated polymer such as polytetrafluoroethylene, polyfluorosulfonic acid, perfluorosulfonate, and polyvinylidene fluoride. Other suitable polymers include polyethylene, polypropylene, polystyrene, polyaniline, polyacrylonitrile, cellophane, cellulose, regenerated cellulose, cellulose acetate, polysulfone, polyurethane, polyvinyl acetate. Typically, the electroactive polymer element includes a biocompatible conductive material such as platinum, gold, silver, palladium, copper, and/or carbon. Commercially available materials suitable for use as a sensor include Nafion® (made by DuPont), Flemion® (made by Asahi Glass), Neosepta® (made by Astom Corporation), Ionac® (made by Sybron Chemicals Inc), Excellion™ (made by Electropure). Other materials suitable for use as a sensor include materials with piezoelectric properties like piezoceramics, electrostrictive polymers, conducting polymers, materials which change their resistance in response to applied strain or force (strain gauges) and elastomers.
The airway implant devices of the present invention, with or without the sensor, can be used to treat snoring. For snoring, the sensor can be adapted and configured to monitor air passageways so as to detect the possible occurrence of snoring or to detect the possible worsening of ongoing snoring. Preferably the sensors are capable of detecting relaxation of tissues in the throat, which can cause them to vibrate and obstruct the airway. Other tissues that can be monitored by the sensor include the mouth, the soft palate, the uvula, tonsils, and the tongue.
Another disease that can be treated with the devices of the present invention includes apnea. The sensor preferably monitors the throat tissue for sagging and/or relaxation to prevent the occurrence of an apneic event. Other tissues that can be monitored by the sensor include the mouth, the soft palate, the uvula, tonsils, and the tongue.
One aspect of the invention is an airway implant device with a connecting element. Preferably the connecting element is used to anchor and/or support the airway implant device, in particular, the deformable element to a rigid structure, such as a bony structure. The invention also includes methods of treating a disease using an airway implant device by implanting in a subject the airway implant device having a deformable element and a connecting element, the implanting step including fastening the deformable element to a bony structure of the subject with the connecting element, wherein the deformable element is capable of modulating the opening of the air passageway. Another method is a method of treating a disease using an airway implant device by implanting a deformable element in a tongue of a subject and linking the deformable element to a jaw bone, the deformable element is capable of supporting the tongue when it is energized. The devices are used to treat sleeping disorders, such as obstructive sleep apnea or snoring.
One embodiment is an airway implant device having a deformable element and a connecting element, wherein the deformable element is capable of modulating the opening of an air passageway and the connecting element is used to fasten the deformable element to a rigid structure. Preferably, the rigid structure is a bony structure. The deformable element can be made of a magnetic material or an electroactive polymer element. In some embodiments, both the deformable element and connecting element are made from a polymeric material. In this embodiment, the polymeric material of the deformable element is typically an electroactive polymer. The electroactive polymer element can include an ion-exchange polymer metal composite. In other embodiments, the electroactive polymer element can include a conducting polymer such as a polypyrrole, a carbon nanotube or a polyaniline.
One embodiment of the airway implant device with a connecting element is depicted in
The deformable element can have a suitable shape such as a flat surface or a tube. Preferably, the deformable element is adapted and configured to expand and contract like an accordion, in particular for an airway implant device that is used for implantation in the tongue. Examples of shapes of the deformable element 8 are depicted in
In another embodiment, the airway implant device with the connecting element further includes an anode, a cathode, a first inductor, and a controller. The anode and cathode are typically connected to the deformable element. The controller typically comprises a microprocessor which is capable of sensing the opening of the air passageway and controlling the energizing of the deformable element. The deformable element is energized with a power supply. For example, when the deformable element is an electroactive polymer element, the power supply is in electrical communication with the deformable element and is activated by electrical energy from the power supply. The deformable element can be physically connected to the power supply for example with a wire lead or can be connected with an inductive coupling mechanism.
In an additional embodiment, the airway implant device with the connecting element further includes a sensor, as described herein. The sensor element is capable of monitoring a condition of an airway to determine likelihood of an apneic event. The condition being monitored is an air passageway gap, air flow pressure, and/or wall tension. The sensor can also provide feedback to modulate the opening of the air passageway by the deformable element.
The airway implant device with a connecting element further includes in some embodiments a non-implanted portion. Preferably the non-implanted portion is in the form of a strip and is used to control the deformable element. Typically this strip includes a power supply and a second inductor, the second inductor capable of interacting with a first inductor.
The connecting element can be used for implanting and/or for retrieving the deformable element, in addition to providing support to the organ being controlled by the airway implant. After implantation, the connecting element typically extends from deformable element to a rigid structure. The connecting element can include at one end an additional anchoring feature to assist with the anchoring to the rigid structure. The connecting element is preferably a wire made of nitinol, stainless steel, titanium or a polymer. The connecting element can be made from one or polymers, such as, for example, polyester or polyethylene; one or more superelastic metals or alloys, such as, for example, nitinol; or from resorbable synthetic materials, such as, for example suture material or polylactic acid.
As set forth above, certain embodiments of the present invention are related to an implantable device for stabilizing the tongue during sleeping.
As is shown in
The Powering/Actuation portion 5005 and its housing can be anchored to the mandibula via a titanium bracket 5004 and titanium bone screws. The actuation mechanisms 5005 can include a Nitinol (actuator type) superelastic shape memory alloys, piezoelectric actuators, and/or electro active polymers, described below in further detail.
The actuator 5005 can be connected to the distal section via a flexible portion 5006 that in one embodiment can be made out of the same actuator material. Alternatively the middle flexible portion 5006 can be made from stainless steel, aramid fiber, polypropylene, nylon or any other suitable material. The flexible portion 5006 can also include a hyaluronic acid (HA) coating to prevent tissue in-growth.
The distal anchor 5008 can be made out of absorbable polymers such as polylactic acid, polyglycolic acid, and so on. Such materials would allow for better integration and anchoring of the implant at the base of the tongue muscle.
The tongue stabilizing mechanism or the middle flexible portion 5024 provides for three-dimensional flexibility for the implant. When powered the flexible portion is stiffened along the central longitudinal axis to hold the tongue in position so as not to block the airway. When not powered, the middle flexible portion 5024 provides for three-dimensional flexibility for the implant, so as to enable the patient to have adequate tongue movement during speaking and swallowing. The middle flexible portion 5024 can include a flexible spring, bellows, etched stent or a combination of the three as the mechanism for supporting the tongue. The middle flexible portion can be coated with an HA coating for preventing tissue in-growth. An important functionality of this mechanism is to permit flexible movement of the tongue in all degrees of freedom during its non active (e.g. non-powered) state. And when the actuator is active, it can tighten the tongue and stabilize it, preventing its multiple degrees of freedom. A tough but flexible material such as a Kevlar fiber 5044 can be used to connect the moving end of the actuation mechanism 5032 to the end of the stabilizing mechanism such that when the actuator moves back it pulls the fiber and stiffens the spring or bellow. It too can be coated with HA coating for preventing tissue growth.
The anchoring mechanism 5026 can include two concentric polyester discs 5050A-5050B with one 5050A connected with the tongue stabilizing mechanism with suture holes around its circumference. The second disc 5050B can also have suture holes 5056 around its circumference which are concentric with the holes in the first disc. Both discs can be connected by one or more polyester rods with holes 5052 for tissue in-growth. The disc further away from the middle flexible portion can be surgically inserted at the base of the tongue at a depth such that the second disc is in contact with the base of the tongue. The surgically implanted disc 5050B can also have one or more polyester rods with polyester beads 5054 to facilitate good tissue in-growth and hence good anchoring.
The tongue implant device in accordance with the embodiments of the present invention can have may alternative configurations, including one or more of the following described embodiments. In a first embodiment the flexible middle portion 5022 can be actuated by a combination of a piezoelectric actuator and a linear motor coupled with a cable to stiffen a spring or bellow structure. In a second embodiment, the flexible middle portion 5022 can be actuated by a combination of a Nitinol or other shape memory material obviating the need for a linear motor and cable arrangement. In a third embodiment, the flexible middle portion 5022 can be actuated by combination of an electro active polymer such as polypyrrole, obviating the need for a linear motor and cable arrangement. Preferably, the Nitinol or the polypyrrole material are of a non-toxic medical grade type. Alternatively, the non-medical grade implant materials are encased or coated in medical grade materials. Such coatings can include a hyaluronic acid, or a poly-Lysine acid coating. The power source for the actuation of the implant device can be a non-implanted power source that is inductively coupled with the power-actuation portion of the tongue implant.
The distal end of the deformable portion 5110 is connected with an anchor member 5112. The anchor 5112 need not be located at the distal end of the deformable portion 5110; it can be located at any length along the deformable portion. The anchor 5112 can be made from an absorbable material. The anchor 5112 is shown to have two sets of anchoring members 5113 and 5114. The distal anchoring member 5113 is configured to prevent an unintended insertion of the implant beyond the desired location, which could cause an exposure of the implant into the oral cavity. The anchor 5112 is also configured to be deployable using a suitable deployment sheath, such a deployment sheath having peal-away portions. Distal tip 5115 is configured have a rounded and narrow shape to render the implant more easily deployable. The anchor 5112 shown in
When the actuation member 5106 is activated, it will pull on fiber 5110 and reduce the flexibility of the deformable member 5108. The tongue stabilizing mechanism or the middle flexible portion 5108 provides for three-dimensional flexibility for the implant. When powered the flexible portion is rendered less flexible along the central longitudinal axis to hold the tongue in position so as not to block the airway. When not powered, the middle flexible portion 5108 provides for three-dimensional flexibility for the implant, so as to enable the patient to have adequate tongue movement during speaking and swallowing. The middle flexible portion can be coated with an HA coating for preventing tissue in-growth. An important functionality of this mechanism is to permit flexible movement of the tongue in all degrees of freedom during its non active (e.g. non-powered) state. And when the actuator is active, it can stabilize the tongue, preventing its multiple degrees of freedom. The implant 5100 can be placed such that its proximal portion is anchored to the mandibula 5002 and its distal portion is anchored to the base of the tongue 5007. The components located inside the housing can all be coated to render them more easily slidable inside the housing during the activation and deactivation of the implant.
Certain aspects of the tongue implant device are directed to a securing or latching mechanism to securely hold the fiber 5110. The latching mechanism will enable the tongue implant to function without needing to be continually powered or activated. In one embodiment, the latching mechanism is configured to be normally closed, in other words the latch is closed when the implant is not powered. The closed latch hold the fiber 5110. As described above, when the implant is powered by either the Nitinol actuator or the linear motor actuator or by way of any of the other actuators described above, a pulling force is imparted on the fiber that runs along the inside of the deformable section so as to reduce the deformable member's flexibility along its axial length. For the implant to remain in this mode, the pulling force needs to be maintained. One way of doing this requires the activation force to be constantly applied by way of constantly powering the implant. Another and more efficient way requires that the pulling force be maintained without having to continually power the implant. The function of the latch mechanism is to enable this functionality. In this normally closed configuration, when the implant is not powered and its deformable portion is in its less flexible mode, the normally closed latch will keep the implant in this less flexible mode. When the implant is powered to transition to its less flexible mode, first the latch is opened to allow the fiber to undergo a pulling action. Then once the flexible portion has completed its transition to its less flexible mode, the implant is unpowered. The unpowering will reset the latch to its closed position and thus maintain the implant in its less flexible mode. The latch mechanism can be made to be coupled with the housing portion. Further details of the operation of the latch mechanism are described below.
The sequence of operation for placing the implant of
The sequence of operation for placing the implant of
The operation of the shape memory actuator material in the tongue implant, starting from a nonpowered state is as follows. With the implant in the nonpowered state, the flexible portion of the implant is in it most flexible state. In this flexible state, the shape memory actuator and the implant are in thermal equilibrium with the body of the patient and thus are at approximately 37° C. Even in a patient experiencing high fever conditions (e.g. about 42° C.), the shape memory actuator material is still in its martensitic (uncontracted state). Once the device is powered, the resistive heating of the shape memory actuator material will cause its temperature to begin to rise, initially approaching As and continuing to Af. The transition in phase from the martensitic to the austenitic phase induced by the resistive heating of the shape memory actuator material will cause a pulling action on the flexible fiber and hence reduce the flexibility of the flexible portion of the implant. The transition time from the martensitic to the austenitic phase can take as long as a few minutes, but is most typically less than 2 minutes. The transition time can also be made extremely small by having an increase in the rate of current flow and its resulting resistive heating. Of course, a desired transition time will take patient comfort into account. The activated implant can then be held in place by the operation of the latch mechanism as described above. The latch mechanism also uses a shape memory actuator material that has the characteristic shown in
The performance characteristic for the shape memory actuator material used in the tongue implant in accordance with
Control device 5720 supplies power to implant device 5710 and controls its operation. Advantageously, control device 5720 and tongue implant 5710 are not physically connected. Instead, control device 5720 transmits power and commands subcutaneously to the implant. In some embodiments, control device 5720 generates an electromagnetic field and sources an inductive power transfer. Commands can be sent to the implant device 5710 by modulating a frequency or amplitude of the electromagnetic field. In one embodiment, commands from control device 5720 include, at least, SET and RELEASE. The SET command can cause the actuator portion of the implant to stabilize the tongue by restricting its movement. For example, as shown in
Control device 5720 can include user interface elements such as command buttons 5724 and status indicator 5722. In one embodiment, command buttons 5724 correspond to commands which can be sent to implant device 5710 and status indicator 5722 reflects a current state of the system. For example, a patient may push a first command button 5724 to issue the SET command to implant device 5710. Powered by control device 5720, implant device 5710 processes the SET command and restricts movement of the patient's tongue. This prevents the closure of the airway passage. Status indicator 5722, for example, may include one or more light emitting diodes to signal that control device 5720 is active and that the SET command has been acknowledged by the implant device. In some embodiments, status indicator 5722 provides audible cues.
When therapy is no longer needed, the patient pushes a second command button 5724 to send the RELEASE command. The RELEASE command is received and processed by implant device 5710 to restore full movement of the tongue. Status indicator 5722, for example, can signal that the RELEASE command has been acknowledged by the implant device and that the actuator electronics are operational. As described herein, a latch mechanism (e.g., latch 5200) can be used to retain the implant device in the less flexible state eliminating the need for a continuous power transfer from control device 5720. Control device 5720 thus provides both a wireless power transfer and commands to implant 5710 and gives the patient full control over the implant's operation.
In response to the reference signal, high-speed driver 5808 rapidly switches a voltage from programmable power supply 5812 causing a current to flow through transmit coil 5810. In one embodiment, high-speed driver 5808 includes an H-bridge driver configured to switch the voltage from programmable power supply 5812 at an operating frequency of approximately 1.8 MHz. As current flows back and forth through transmit coil 5810, an expanding and collapsing electromagnetic (EM) field is created in the surrounding area. The amplitude of the EM field can be controlled by the output of programmable power supply 5812 and its frequency can be determined by the resonant frequency of the transmit circuit. The electromagnetic field produced by transmit coil 5810 can support an inductive power transfer to the electronics of the implant device.
In an exemplary embodiment, transmit coil 5810 includes a half-pot ferrite core wound with Litz wire. The half-pot core is configured to constrain the electromagnetic field to a localized area. This simultaneously increases its magnitude and reduces potential interference with the electronics of control device 5800. In one embodiment, transmit coil 5810 is connected in series with a capacitance to create a load which resonates at approximately 1.8 MHz. The amount of the capacitance can be changed to effect a change in the resonant frequency of the transmit circuit. In some embodiments, additional capacitance can be switched in (or out) of the transmit circuit to changes a frequency of the electromagnetic field. The frequency modulation, in turn, can be detected as a command by the implant.
Processor 5802 coordinates the operation of the transmit circuit along with communications circuit 5814, programmable power supply 5812, and user interface 5804. In some embodiments, processor 5802 is a general purpose microprocessor configured to execute program instructions and can be coupled to one or more memory elements. For example, processor 5802 can retrieve program instructions and configuration data from a read-only (ROM) and can store data and program instructions in a random-access (RAM) memory. The memory elements can provide volatile or non-volatile storage. In some embodiments, processor 5802 is a microcontroller which has embedded peripherals. For example, an exemplary microcontroller for use in control device 5720 can include embedded memory, analog-to-digital converter, and oscillator elements. In still other embodiments, processor 5812 can be an application-specific integrated circuit (ASIC).
In operation, processor 5802 receives input from user-interface 5804 and causes control device 5800 to supply power and commands to the implant. In some embodiments, control device 5800 sends commands by modulating an amplitude of the electromagnetic field produced by transmit coil 5810. These commands can be received by the implant as serial binary data.
As shown, processor 5802 is coupled to programmable power supply 5812 and controls a voltage at its output. Processor 5802 can vary the output voltage of programmable power supply 5812 based on the command to be sent. The output voltage, in turn, is delivered to high speed driver 5808 and determines an amplitude of the electromagnetic field. By modulating the amplitude, serial binary commands can be sent to the implant. For example, one amplitude-modulated sequence may be used to send the SET and another may be used to send the RELEASE command. It should be noted that processor 5802 can maintain the EM field at a level sufficient to provide an inductive power transfer for operating the implant electronics while, at the same time, communicating a command.
Processor 5802 can also respond to inputs from user-interface 5804 by modulating a frequency of the transmit circuit. For example, in one embodiment, processor 5802 is a microcontroller and oscillator 5806 is an embedded peripheral of the microcontroller. To send a command, processor 5802 can vary the resonant frequency of transmit coil 5810 by adding or removing a capacitance. For example, processor 5802 can be configured to control a relay which switches series capacitance in or out of the transmit circuit thereby changing its resonant frequency. In an exemplary embodiment, a frequency of 1.8 MHz corresponds to the SET command whereas a frequency of 1.3 MHz corresponds to the RELEASE command. By modulating the frequency of the EM field, control device 5800 can send a range of commands to the implant while also supplying power for operating the implant electronics.
Processor 5802 can also receive messages sent by the implant device. As shown, processor 5802 receives an output signal from communications circuit 5814. Communications circuit 5814 is coupled to transmit coil 5810 and receives a signal representative of coil voltage at its input. When the implant device receives an inductive power transfer from control device 5800 and uses the power supplied to it by the control device, a voltage across the transmit coil changes. Communications circuit 5814 monitors these changes to detect responses from the implant.
In one embodiment, response messages are detected as pulses and communication circuit 5814 measures a duration of the pulses based on changes in the coil voltage. Communication circuit 5814 delivers the response messages to processor 5802 which can update user interface 5804 or take other action. For example, in response to receiving an error message, processor 5802 can illuminate an LED at user interface 5804 and/or de-energize the transmit circuit. Communication with the implant device is discussed below.
Control device 5800 can also include a number of safety features. As shown, processor 5802 monitors output voltage/current levels of programmable power supply 5812. When the voltage or current exceed safe levels, processor 5802 can disable programmable power supply 5812 or adjust its output. Similarly, processor 5802 can monitor the temperature and voltage of transmit coil 5810. In the event that these values reach unsafe levels, processor 5802 can disable oscillator 5806 and/or high speed driver 5808. In one embodiment, processor 5802 can determine an amount of power transferred to the implant device over a predetermined interval and adjust or disable programmable power supply 5812, oscillator 5806, and high-speed driver 5808 when the power transfer exceeds a predetermined amount. Processor 5802 can also be configured to time-limit power transfers for controlling thermal build-up at the implant device. For example, processor 5802 may disable programmable power supply 5812 when a power transfer lasts longer than 30 seconds.
In one embodiment, implant electronics 5900 operate to receive an inductive power transfer and commands from the control device. When the control device is positioned near the implant, the electromagnetic field from transmit coil 5810 can induce a voltage in the receive coil 5902. For example, the control device may be held under a patient's chin so that power and commands are conveyed by the electromagnetic field to the implant device. Receiver coil 5902 can include an air-core inductor or like elements for receiving an inductive power transfer.
As shown, receiver coil 5902 is coupled to actuator switches 5908, 5910 and to voltage regulator 5904. Voltage regulator 5904 converts the unregulated coil voltage into a relatively stable operating voltage. Processor 5906 receives the relatively stable voltage from voltage regulator 5904 and monitors the amplitude and/or frequency of the receiver coil voltage for commands from the control unit. Processor 5906 can be a microprocessor, microcontroller, or ASIC. In some embodiments, processor 5906 is similar to processor 5802.
When commands are detected, processor 5906 outputs control signals to main actuator switch 5908 and latch actuator switch 5910 for controlling the implant device. In some embodiments, the control signals are pulse-width modulated to restrict power delivery to levels appropriate for actuators 5912, 5914. Main actuator switch 5908 responds to its control signal by delivering power from receiver coil 5902 to main actuator 5912. Similarly, latch actuator switch 5910 responds to its control signal by delivering power from receiver coil 5902 to latch actuator 5914. Power from the control device thus activates processor 5906 which, in turn, controls the operation of actuators 5912, 5914.
Processor 5906 can detect commands based on the amplitude of the receiver coil voltage. In the embodiment shown, processor 5906 receives measured values of the receiver coil voltage from voltage regulator 5904. These measured values can be detected as serial binary data which represent commands from the control device. Processor 5906 can recognize a specific command based on the amplitude measurements. For example, one amplitude modulated sequence of the receiver coil voltage may be detected as the SET command and another amplitude modulated sequence may be detected as the RELEASE command. In some embodiments, program instructions and data may also be received from the control device as serial binary data using amplitude modulation of the electromagnetic field.
In some embodiments, processor 5906 can detect a command based on a frequency of the coil voltage. As shown, processor 5906 is coupled with receiver coil 5902 and can determine a frequency of the coil voltage. Among other techniques, processor 5906 can measure frequency by counting the number of cycles of the coil voltage signal detected in a predetermined interval. Processor 5906 then determines a type of command based on the measured value. For example, a frequency of 1.8 MHz may correspond to the SET command whereas a frequency of 1.3 MHz may correspond to the RELEASE command. In various embodiments, processor 5906 may recognize commands based on a combination of frequency and amplitude values.
Based on the command, processor 5906 can power either main actuator 5912 or latch actuator 5914. In response to the SET command, processor 5906 may cause switch 5908 to deliver power to main actuator 5912. As an example, main actuator 5912 may comprise a shape memory material such as first Nitinol coil 5302 discussed in connection with
In an alternative embodiment, main actuator 5912 can be a motor such as piezo-electric motor 5025. Piezo-electric motor 5025 can maintain its position when deactivated so that a latch mechanism may not be needed. Thus, in such embodiments, processor 5802 can respond to a SET command by driving piezo-electric motor 5025 in a first direction to restrict the flexible portion 5024. When a RELEASE command is received, processor 5802 can reverse the operation of piezo-electric motor 5025 to restore full flexibility.
Processor 5906 can also be configured to send response messages to the control device. In one embodiment, response messages are sent by pulsing the control signal to the main and/or latch actuator switches 5908, 5910 for predetermined intervals. Pulses can be of short duration such that the actuators 5912, 5914 do not change states (“no-operation” pulses), but long enough for the control device to detect that the implant device is drawing additional power. As previously noted, some embodiments of the control device (e.g., control device 5800) can detect voltage changes at transmit coil 5810 corresponding to operation of the implant. By modulating the length of the no-operation pulses, processor 5906 can communicate with the control device. For example, processor 5906 can communicate a state of the implant device with the no-operation pulses.
Frequency-amplitude detector 6004 detects commands from the control device based on characteristics of the receiver coil voltage. For example, when frequency modulation is used for communicating with the implant device, frequency-amplitude detector 6004 measures a frequency of the voltage induced in receiver coil 5902 and determines a command corresponding to the measured value. By way of illustration, a frequency of 1.8 MHz might correspond to a first command whereas a frequency of 1.3 MHz might correspond to a second command. Alternatively or additionally, frequency-amplitude detector 6004 can be configured to measure an amplitude of the receiver coil voltage and to determine command based on amplitude values, frequency values, or any combination thereof.
Communication module 6006 is configured to generate no-operation pulses for sending response message to the control device. In one embodiment, a total of four response messages are provided. An exemplary set of response messages is illustrated in the table below.
The IDLE response can be used to signify to the control device that the implant is functioning and awaiting a command. As shown, IDLE can be communicated by generating no-operation pulses at regular intervals which have the specified pulse duration. ACK can be used to acknowledge receipt of a command (such as SET or RELEASE) prior to its execution and can be communicated with one or more 0.4 ms no-operation pulses. Different error conditions can also be signaled. ERR1 and ERR2, for example, can represent a minor and serious error condition, respectively. A minor error may indicate that a command from control device was not received correctly, whereas a serious error could signify malfunction of the implant device. Minor errors can be indicated with 0.65 ms no-operation pulses whereas serious errors may be signaled by no-operation pulses having a duration of 0.85 ms. Although not a response per se, an extended pulse (1+ ms) such as that generated when operating actuators 5912, 5914 can be interpreted as PWR message. In other words, an extended pulse can be interpreted by control device to mean that actuators 5912, 5914 are operating.
Memory 6008 can store configuration data and program instructions executed by processor 5906. For example, memory 6008 can store a table of response data, code for measuring the frequency and/or amplitude of the receiver coil voltage, code for detecting commands, code for determining pulse-width modulation of the control signals, and other instructions and data used in carrying out operations of the tongue implant device. Although shown as part of processor 5906, memory 6008 can be external to processor 5906 and can include both volatile and non-volatile storage elements.
At block 6106, the implant device receives the power transfer signal and becomes operational. This may occur, for example, when voltage regulator 5094 supplies an operating voltage to processor 5906. When the implant device is operational, block 6108, it sends an IDLE message to the control device signifying that it is ready to receive commands. On the other hand, if an error condition is detected, the implant may instead send an error message. In that case, the control device can display information about the error condition at its user interface. For example, status indicator 5722 may illuminate one or more LEDs or provide an audible cue to signal that an error has been detected. This may prompt the patient to reposition the control device in relation to the implant and to send the command a second time.
In response to receiving the IDLE message, at block 6110, the control device sends the user-input command to the implant device. For example, the command may be a SET command for placing the implant into its restricted or less-flexible state, a RELEASE command for restoring the implant to its fully flexible state, or some other command. At block 6112, the implant detects the command and sends an ACK message to the control device. The command may be detected based on the frequency and/or amplitude of the power transfer signal and the ACK message may be generated with no-operation pulses having a predetermined duration.
At block 6114, the implant powers the appropriate actuator to execute the command. This can include, for example, energizing a piezo-electric motor or shape memory material for setting the implant device or powering a latch mechanism for releasing the implant device. The control device may detect that the actuators are operating and may signal to the patient that the implant is changing states. For example, the control device may update a user-interface according to the state of the implant.
In some embodiments, the EAP element is an IPMC strip which is made from a base material of an ionomer sheet, film or membrane. The ionomer sheet is formed using ionomer dispersion.
IPMC is made from the base ionomer of, for example, polyethylene, polystyrene, polytetrafluoroethylene, polyvinylidene fluoride (PVDF) (e.g., KYNAR® and KYNAR Flex®, from ATOFINA, Paris, France, and SOLEF®, from Solvay Solexis S.A., Brussels, Belgium), hydrophilic-PVDF (h-PVDF), polyfluorosulfonic acid based membranes like NAFION® (from E.I. Du Point de Nemours and Company, Wilmington, Del.), polyaniline, polyacrylonitrile, cellulose, cellulose acetates, regenerated cellulose, polysulfone, polyurethane, and combinations thereof. The conductive material that is deposited on the ionomer can be gold, platinum, silver, palladium, copper, graphite, conductive carbon, or combinations thereof. Conductive material is deposited on the ionomer either by electrolysis process, vapor deposition, sputtering, electroplating, or combination of processes.
The IPMC is cut into the desired implant shape for the EAP element. The electrical contact (e.g., anode and cathode wires for EAP element) is connected to the IPMC surfaces by, for example, soldering, welding, brazing, potting using conductive adhesives, or combinations thereof. The EAP element is configured, if necessary, into specific curved shapes using mold and heat setting processes.
In some embodiments, the EAP element is insulated with electrical insulation coatings. Also, the EAP element can be insulated with coatings that promote cell growth and minimize fibrosis, stop cell growth, or kill nearby cells. The insulation can be a biocompatible material. The EAP element is coated with polymers such as polypropylene, poly-L-lysine, poly-D-lysine, polyethylene glycol, polyvinyl alcohol, polyvinyl acetate, polymethyl methacrylate, or combinations thereof. The EAP element can also be coated with hyaluronic acid. The coating is applied to the device by standard coating techniques like spraying, electrostatic spraying, brushing, vapor deposition, dipping, etc.
In one example, a perfluorosulfonate ionomer, PVDF or h-PVDF sheet is prepared for manufacturing the EAP element. In an optional step, the sheet is roughened on both sides using, for example, about 320 grit sand paper and then about 600 grit sand paper; then rinsed with deionized water; then submerged in isopropyl alcohol (IPA); subjected to an ultrasonic bath for about 10 minutes; and then the sheet is rinsed with deionized water. The sheet is boiled for about 30 minutes in hydrochloric acid (HCL). The sheet is rinsed and then boiled in deionized water for about 30 minutes. The sheet is then subject to ion-exchange (i.e., absorption). The sheet is submerged into, or otherwise exposed to, a metal salt solution at room temperature for more than about three hours. Examples of the metal salt solution are tetraammineplatinum chloride solution, silver chloride solution, hydrogen tetrachloroaurate, tetraamminepalladium chloride monohydrate or other platinum, gold, silver, carbon, copper, or palladium salts in solution. The metal salt solution typically has a concentration of greater than or equal to about 200 mg/100 ml water. 5% ammonium hydroxide solution is added at a ratio of 2.5 ml/100 ml to the tetraammineplatinum chloride solution to neutralize the solution. The sheet is then rinsed with deionized water. Primary plating is then applied to the sheet. The sheet is submerged in water at about 40° C. 5% solution by weight of sodium borohydride and deionized water is added to the water submerging the sheet at 2 ml/180 ml of water. The solution is stirred for 30 minutes at 40° C. The sodium borohydride solution is then added to the water at 2 ml/180 ml of water and the solution is stirred for 30 minutes at 40° C. This sodium borohydride adding and solution stirring is performed six times total. The water temperature is then gradually raised to 60° C. 20 ml of the sodium borohydride solution is then added to the water. The solution is stirred for about 90 minutes. The sheet is then rinsed with deionized water, submerged into 0.1N HCl for an hour, and then rinsed with deionized water.
In some embodiments, the sheet receives second plating. The sheet is submerged or otherwise exposed to a tetraammineplatinum chloride solution at a concentration of about 50 mg/100 ml deionized water. 5% ammonium hydroxide solution is added at a rate of 2 ml/100 ml of tetrammineplatinum chloride solution. 5% by volume solution of hydroxylamine hydrochloride in deionized water is added to the tetraammineplantium chloride solution at a ratio of 0.1 of the volume of the tetraammineplatinum chloride solution. 20% by volume solution of hydrazine monohydrate in deionized water is added to the tetraammineplatinum chloride solution at a ratio of 0.05 of the volume of the tetraammineplantinum chloride solution. The temperature is then set to about 40° C. and the solution is stirred.
A 5% solution of hydroxylamine hydrochloride is then added at a ratio of 2.5 m/100 ml of tetraammineplatinum chloride solution. A 20% solution of hydrazine monohydrate solution is then added at a ratio of 1.25 ml/100 ml tetraammineplatinum chloride solution. The solution is stirred for 30 minutes and the temperature set to 60° C. The above steps in this paragraph can be repeated three additional times. The sheet is then rinsed with deionized water, boiled in HCl for 10 minutes, rinsed with deionized water and dried.
In some embodiments, the polymer base is dissolved in solvents, for example dimethyl acetamide, acetone, methylethyle ketone, toluene, dimethyl carbonate, diethyl carbonate, and combinations thereof. The solvent is then allowed to dry, producing a thin film. While the solution is wet, a low friction, (e.g., glass, Teflon) plate is dipped into the solution and removed. The coating on the plate dries, creating a think film. The plate is repeatedly dipped into the solution to increase the thickness of the film.
Polyvinyl alcohol, polyvinyl pyrrolidone, polyinyl acetate or combinations thereof can be added to a PVDF solution before drying, thus contributing hydrophilic properties to PVDF and can improve ion migration through the polymer film during manufacture. Dye or other color pigments can be added to the polymer solution.
During sleep, the muscles in the roof of the mouth (soft palate), tongue and throat relax. If the tissues in the throat relax enough, they vibrate and may partially obstruct the airway. The more narrowed the airway, the more forceful the airflow becomes. Tissue vibration increases, and snoring grows louder. Having a low, thick soft palate or enlarged tonsils or tissues in the back of the throat (adenoids) can narrow the airway. Likewise, if the triangular piece of tissue hanging from the soft palate (uvula) is elongated, airflow can be obstructed and vibration increased. Being overweight contributes to narrowing of throat tissues. Chronic nasal congestion or a crooked partition between the nostrils (deviated nasal septum) may be to blame.
Snoring may also be associated with sleep apnea. In this serious condition, excessive sagging of throat tissues causes your airway to collapse, preventing breathing. Sleep apnea generally breaks up loud snoring with 10 seconds or more of silence. Eventually, the lack of oxygen and an increase in carbon dioxide signal causes the person to wake up, forcing the airway open with a loud snort.
Obstructive sleep apnea occurs when the muscles in the back of the throat relax. These muscles support the soft palate, uvula, tonsils and tongue. When the muscles relax, the airway is narrowed or closed during breathing in, and breathing is momentarily cut off. This lowers the level of oxygen in the blood. The brain senses this decrease and briefly rouses the person from sleep so that the airway can be reopened. Typically, this awakening is so brief that it cannot be remembered. Central sleep apnea, which is far less common, occurs when the brain fails to transmit signals to the breathing muscles.
Thus, it can be seen that airway disorders, such as sleep apnea and snoring, are caused by improper opening of the airway passageways. The devices and methods described herein are suitable for the treatment of disorders caused by the improper opening of the air passageways. The devices can be implanted in any suitable location such as to open up the airways. The opening of the passageways need not be a complete opening and in some conditions a partial opening is sufficient to treat the disorder.
In addition to air passageway disorders, the implants disclosed herein are suitable for use in other disorders. The disorders treated with the devices include those that are caused by improper opening and/or closing of passageways in the body, such as various locations of the gastro-intestinal tract or blood vessels. The implantation of the devices are suitable for supporting walls of passageways The devices can be implanted in the walls of the gastro-intestinal tract, such as the esophagus to treat acid reflux. The gastro-intestinal tract or blood vessel devices can be used in combination with the sensors described above. Also, the implants and/or sphincters can be used for disorders of fecal and urinary sphincters. Further, the implants of the invention can be tailored for specific patient needs.
As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.
The present application is a continuation-in-part of U.S. patent application Ser. No. 11/847,271 (atty. docket no. 026705-000620US), filed Aug. 29, 2007, which is a continuation-in-part of U.S. patent application Ser. No. 11/737,107, filed Apr. 18, 2007, which claims priority to U.S. Provisional Patent Application No. 60/745,254, filed Apr. 20, 2006, all of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60745254 | Apr 2006 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11847271 | Aug 2007 | US |
| Child | 12250398 | US | |
| Parent | 11737107 | Apr 2007 | US |
| Child | 11847271 | US |
