FOOD INTAKE RESTRICTION DEVICE

Abstract: A food intake restriction device for forming a stoma opening in the stomach or esophagus of a patient comprises an elongated restriction member (2), forming means for forming the elongated restriction member into at least a substantially closed loop around the stomach or esophagus, said loop defining a restriction opening, and an adjustment means for adjusting the restriction member in said loop to change the size of the restriction opening. The device further comprises implantable hydraulic operation means (6, 8) provided for operating the adjustment means in a non-invasive manner, and an implantable reservoir (4) containing a predetermined amount of hydraulic fluid. The hydraulic operation means are adapted to operate the adjustment means by using the hydraulic fluid of the reservoir.

Description: Food intake restriction device The present invention relates to a food intake restriction device for forming a stoma opening in the stomach or esophagus of a patient, the device comprising an elongated restriction member, forming means for forming the elongated restriction member into at least a substantially closed loop around the stomach or esophagus, said loop defining a restriction opening, and an adjustment means for adjustment of the restriction member in said loop to change the size of the restriction opening. The term "patient" includes an animal or a human being. Food intake restriction devices in the form of gastric banding devices, in which a band encircles a portion of a patient's stomach to restrict the food intake of the patient, have been used in surgery for morbid obesity to form a small gastric pouch above the band and a reduced stoma opening in the stomach. Although such a band is applied around the stomach to obtain an optimal stoma opening during surgery, some prior gastric banding devices are provided with an adjustment means enabling a minor pos -operation adjustment of the size of the stoma opening. In all such prior art devices such as disclosed in U.S. Patent No. 4,592,339, European Patent No. 0611561 and International Patent Application WO 94/27504, the adjustment means typically comprises an inflatable cavity in the band and an injection port in fluid connection with the inflatable cavity. The injection port is subcutaneously implanted to allow the addition of fluid to or withdrawal of fluid from the cavity by an injection needle penetrating the patient's skin into the injection port. In practice, the band is made of silicone rubber which is a material approved for implantation and the fluid is a liquid such as an isotonic salt solution. It has been found, however, that the bands of this type of prior art devices used for forming a stoma opening in a patient's stomach may eventually dislocate downwardly on the stomach and there is an increased risk of stoma stenosis due to a small range of adjustment of the band. It has also been found that the volume of the gastric pouch above the band increases in size up to ten times after operation. Therefore the pouch volume during surgery needs to be very small, approximately 7 ml . To enable the patient to feed the stomach with sufficient nutrition immediately after an operation considering such a small gastric pouch, the stoma initially needs to be relatively large and later needs to be substantially reduced, as the pouch volume increases. To be able to achieve a significant range of adjustment of the band, the cavity in the band has to be relatively large and is defined by a thin flexible wall, normally made of silicone material. Furthermore, the size of the stoma opening has to be gradually reduced during the first year after surgery as the gastric pouch increases in size. As indicated above, the reduction of the stoma opening using the prior art implantable devices is achieved by adding liquid to the cavity of the band via the injection port to expand the band radially inwardly. A great disadvantage of repeatedly injecting liquid via the injection port is the increased risk of the patient getting an infection in the body area surrounding the injection port. If such an infection occurs the injection port has to be surgically removed from the patient. Moreover, such an infection might be spread along the tube interconnecting the injection port and the band to the stomach, causing even more serious complications. Thus, the stomach might be infected where it is in contact with the band, which might result in the band migrating through the wall of the stomach. Also, it is uncomfortable for the patient when the necessary, often many, post-operation adjustments of the stoma opening are carried out using an injection needle penetrating the skin of the patient into the injection port. It may happen that the patient swallows pieces of food too large to pass through the restricted stoma opening. If that occurs the patient has to visit a doctor who can remove the food pieces, if the band design so permits, by withdrawing some liquid from the band to enlarge the stoma opening to allow the food pieces to pass the stoma. Then, the doctor has to add liquid to the band in order to regain the restricted stoma opening. Again, these measures require the use of an injection needle penetrating the skin of the patient, which is uncomfortable for the patient. Another problem with the known adjustable gastric banding devices is that there is a risk of leakage from the band cavity occurring some time after the operation. An object of the invention is to provide a food intake restriction device for forming a stoma opening in the stomach or esophagus of a patient which does not require the use of an injection needle for accomplishing post-operation adjustments of the stoma opening. Another object of the invention is to provide a food intake restriction device for forming a stoma opening in the stomach or esophagus of a patient which permits post -operation adjustments that are comfortable for the patient. " ϊet another object of the invention is to provide a food intake restriction device for forming a stoma opening in the stomach or esophagus of a patient in which the risk of liquid leaking from the device is substantially reduced. These objects are obtained by a device of the kind stated initially which is characterised in that implantable hydraulic operation means are provided for operating the adjustment means in a non- invasive manner, and that an implantable reservoir containing a predetermined amount of hydraulic fluid is provided, the hydraulic operation means being adapted to operate the adjustment means by using the hydraulic fluid of the reservoir. Thus, there is no need for an injection port for accomplishing necessary post -operation adjustments of the restriction opening to change the zize of the stoma opening. (In certain applications, however, an injection port connected to the reservoir may be provided for enabling, normally a single once-and-for-all, calibration of the predetermined amount of fluid in the reservoir.) In accordance with a first main embodiment of the invention, the adjustment means comprises an expandable cavity in the restriction member, the size of the restriction opening being reduced upon expansion of the cavity and increased upon contraction of the cavity, and the hydraulic operation means are adapted to distribute hydraulic fluid from the reservoir to expand the cavity, and to distribute hydraulic fluid from the cavity to the reservoir to contract the cavity, to thereby control the size of the restriction opening. Generally, the adjustment means may be adapted to change the size of the restriction opening such that the outer circumferential confinement surface of the restriction member is changed, or, alternatively, is unchanged. The forming means may advantageously be adapted to form the restriction member into a loop having a predetermined size. A fluid distribution tube may be connected between the reservoir and the cavity in a manner so that the tube does not interfere with the forming means, such as coupling elements on the ends of the elongated restriction member. That is, the tube may be connected to the restriction member at a position spaced from the forming means. Preferably, the reservoir defines a chamber for the predetermined amount of fluid and the hydraulic operation means are adapted to change the size of the chamber. The hydraulic operation means suitably comprise first and second wall portions of the reservoir, which are displaceable relative to each other to change the size of the chamber of the reservoir. The hydraulic operation means may be adapted to distribute fluid from the reservoir to the cavity of the restriction member in response to a predetermined first displacement- of the first wall portion of the reservoir relative to the second wall portion of the reservoir and to distribute fluid from said cavity to the reservoir in response to a predetermined second displacement of said first wall portion relative to said second wall portion. The first and second wall portions of the reservoir may be designed to be displaceable relative to each other by manual manipulation thereof, such as by manually pushing, pulling or rotating any of the wall portions in one direction, or alternatively, may be displaceable relative to each other by a device powered magnetically, hydraulically, or electrically (e.g. by an electric motor) . In this embodiment no pump, is used, only the volume of the reservoir is varied. This is of great advantage compared to the solution described below when a pump is used to pump fluid between the reservoir and the adjustment means because there is no need for a non-return valve and it is still possible to have fluid going both to and from the reservoir. In accordance with a particular embodiment of the invention, the hydraulic operation means comprise an activatable pump adapted to pump fluid between the reservoir and the cavity of the restriction member. The pump preferably comprises a first activation member for activating the pump to pump fluid from the reservoir to the cavity of the restriction member, and a second activation member for activating the pump to pump fluid from the cavity to the reservoir. The first and second activation members may be operable by manual manipulation thereof, such as by manually pushing, pulling or rotating any of the activation members in one direction.- At least one of the activation members is constructed to operate when subjected to an external pressure exceeding a predetermined magnitude. As an alternative to the manual manipulation, at least one of the first and second activating members may be operable by a device powered magnetically, hydraulically, or electrically (e . g. by an electric motor). The pump may pump fluid both to and away from the adjusment means or hydraulic means controlling the adjustment means. A mechanical solution is proposed in which it is possible to pump in both directions just by pushing an activating member in one direction. Another alternative is a pump pumping in only one direction and. an adjustable valve to change the direction of fluid to either increase or decrease the amount of fluid in the reservoir. This valve may be manipulated either manually, mechanically, magnetically, or hydraulically. Any kind of motor could be used for the different operations as well as wireless remote solutions . Wherever a magnetic means is utilized according to the invention it may comprise a permanent magnet and a magnetic material reed switch, or other suitable known or conventional magnetic devices. In accordance with a second main embodiment of the invention, the restriction member is non-inflatable, and the adjustment means is adapted to mecanically adjust the restriction member in said loop. In accordance with another particular embodiment of the invention, the hydraulic operation means comprise a servo means, suitably including hydraulic means. Alternatively, the servo means may include magnetic or electric means. Preferably, the servo means comprises a servo reservoir defining a chamber containing servo fluid and the hydraulic operation means comprise first and second wall portions of the servo reservoir, which are displaceable relative to each other to change the size of the chamber of the servo reservoir. The same principle will apply for the servo reservoir as for the earlier described reservoir ■ wherein the volume in the servo reservoir may be increased or decreased by a first or second displacement of the first wall portion relative to the second wall portion of the servo reservoir and thereby control the earlier described reservoir and thereby indirectly control the restriction opening. The first and second wall portions of the servo reservoir may be displaceable relative to each other by manual manipulation thereof, such as by manually pushing, pulling or rotating any of the wall portions of the servo reservoir in one direction. Alternatively, the first and second wall portions may be displaceable by magnetically, hydraulically or electrically powered devices. These powered devices may all be activated by manual manipulating means preferably located subcutaneously. This activation may be indirect, for example via a switch. Especially when manual manipulation means are used, the servo means is suitable to use. With servo means less force is needed for controlling the adjustment device. Hydraulic operation is preferably used with the servo means. One example is a closed system that controls another closed system in which hydraulic components of the adjusment means are incorporated. Minor changes in the amount of fluid in a reservoir of the first system could then lead to major changes in the amount of fluid in a reservoir in the second system. Consequently, the change in volume in the reservoir of the second system affects the hydraulic operation of the adjustment device which is incorporated in the second closed system. The great advantage of such a servo means is that the larger volume system could be placed at a suitable location, e.g. inside the abdomen where there is more space, and still it would be possible to use manual manipulation means of the smaller system subcutaneously. The servo reservoir could control the reservoir of the larger volume . The servo reservoir could be controlled directly or indirectly by a small fluid supply reservoir, which may be placed subcutaneously and may be activated by manual manipulation means controlling the servo reservoir or other suitable device. Preferably, the hydraulic operation means comprise first and second wall portions of the fluid supply reservoir, which are displaceable relative to each other to change the size of the chamber of the fluid supply reservoir. The hydraulic operation means may distribute fluid from the fluid supply reservoir to the servo reservoir in response to a predetermined first displacement of the first wall portion of the fluid supply reservoir relative to the second wall portion of the fluid supply reservoir and to distribute fluid from the servo reservoir to the fluid supply reservoir in response to a predetermined second displacement of the first wall portion relative to the second wall portion. The wall portions of the fluid supply reservoir may be displaceable relative to each other by manual manipulation means or be displaceable relative to each other by manual manipulation means for pushing, pulling, or rotating any of the wall portions of the fluid supply reservoir in one direction. Alternatively, the wall portions of the fluid supply reservoir may be displaceable relative to each other by magnetic means, hydraulic means, manually manipulated means, or electrical control means including an electric motor. The magnetic means, hydraulic means, or electrical control means may all be activated by manually manipulated means preferably located subcutaneously. This control may be indirect, for example via a switch. Even in the broadest embodiment of the invention the adjustment means may comprise a servo means. The servo means may comprise a hydraulic means, an electric control means, a magnetic means, mechanical means, or a manual manipulating means. The- hydraulic means, electric control means, mechanical means or magnetic means may be activated by manual manipulating means. Using a servo system will save the use of force when adjusting the adjustment device which may be of importance in many applications. All systems according to the invention may be controlled by a wireless remote control means. In accordance with an advantageous embodiment of the invention, there is provided a wireless remote control means for non-invasively controlling the hydraulic operation means. The remote control means may advantageously be capable of obtaining information on the size of the restriction opening and to command the hydraulic operation means to operate the adjustment means to adjust the restriction member in response to obtained information. The remote control means comprises means for wireless transfer of energy from outside the patient's body to energy consuming mplantable components of the device. An implantable motor may suitably be provided for operating the hydraulic operation means and said means for wireless transfer of energy may be adapted to directly power the motor with transferred energy. The energy transferred by said means for transfer- of energy may comprise wave signals, an electric field or a magnetic field. Preferably, the wireless remote control means comprises separate signal transmitting means and implantable signal receiving means. For example, the signal transmitting and signal receiving means may be adapted to transmit and receive signals in the form of digital pulses, which may comprise a magnetic or electric field. Alternatively, which is preferred,, the signal transmitting and signal receiving means may be adapted to transmit and receive signals, which may comprise electromagnetic waves, sound waves or carrier waves for remote control signals. The receiving means may comprise a control unit adapted to control the hydraulic operation means in response to signals from the signal transmitting means. The food intake restriction device may further comprise an implantable energizer unit for providing energy to energy consuming components of the device to be implanted in the patient, such as electronic circuits and/or a motor for operating the hydraulic operation means. The control unit may be adapted to power such an implanted motor with energy provided by the energizer unit in response to signals received from the signal transmitting means. Any known or conventional signal transmitting or signal receiving device that is suitable for use with a human or mammal patient may be provided as the signal transmitting or signal receiving means. The signals may comprise electromagnetic waves, such as infrared light, visible light, laser light, micro waves, or sound waves, such as ultrasonic waves or infrasonic waves, or any other type of wave signals. The signals may also comprise electric or magnetic fields, or pulses. All of the above-mentioned signals may comprise digital signals. The motor may be any type of motor, such as a pneumatic, hydraulic or electric motor and the energizer unit may be adapted to power the motor with pressurized gas or liquid, or electrical energy, depending on the type of motor. Where the motor is an electric motor, it may power pneumatic or hydraulic equipment . The energizer unit may comprise a power supply and the control unit may be adapted to power the motor with energy from the power supply. Preferably, the power supply is an electric power supply, such as a battery, and the motor is an electric motor. In this case, the battery also continuously powers the circuitry of the signal receiving means between the adjustment operations, in order to keep the signal receiving means prepared for receiving signals transmitted from the signal transmitting means. Ihe energizer unit may be adapted to transfer energy from the signals, as they are transmitted to the signal receiving means, into electric energy for powering the implanted electronic components. For example, the energizer unit may be adapted to transfer the energy from the signals into direct or alternating current. In case there is an implanted electric motor for operating the hydraulic operation means the energizer unit may also power the motor with the transferred energy. Advantageously, the control unit is adapted to directly power the electric motor with electric energy, as the energizer unit transfers the signal energy into the electric energy. This embodiment is particularly simple and does not require any recurrent invasive measures for exchanging empty power supplies, such as batteries, that is required in the first embodiment described above . For adjustment means of the type that requires more, but still relatively low, power for its operation, the energizer unit may comprise a rechargeable electric power supply for storing the electric energy obtained and the control unit be adapted to power the electric motor with energy from the rechargeable electric power supply in response to signals received from the signal transmitting means. In an initial charging step the rechargeable power supply can be charged over a relatively long time ( e. g. a few seconds up to a half hour) without powering the electric motor. In a following operating step, when the power supply has been charged with sufficient energy, the control unit powers the electric motor with energy from the charged power supply to operate the hydraulic operation means, so that a desired change of the patient's stoma opening is achieved. If the capacity of the power supply is insignificant to achieve the necessary adjustment in one single operating step, the above steps may conveniently be repeated until the desired adjustment is achieved. The electric power supply suitably comprises an inexpensive simple capacitor. In this case, the electric motor may be a stepping motor. The signal transmitting means may be adapted to transmit electromagnetic signals and the energizer unit be adapted to draw radiant energy from the electromagnetic wave signals, as they are transmitted to the signal receiving means, and transfer the radiant energy into electric energy. Alternatively, the energizer unit may comprise a battery, an electrically operable switch adapted to connect the battery to the signal receiving means in an "on" mode when the switch is powered and to keep the battery disconnected from the signal receiving means in a "standby" mode when the switch is unpowered, and a rechargeable electric power supply for powering the switch. The control unit may be adapted to power the electric motor with energy from the battery in response to signals received from the signal transmitting means, when the switch is in its "on" mode. Advantageously, the energizer unit may be adapted to transfer wave energy from the signals, as they are transmitted to the signal receiving means, into a current for charging the rechargeable electric power supply, which suitably is a capacitor. Energy from the power supply is then used to change the switch from "off" (standby mode) to "on" . This embodiment is suited for adjustment means of the type that require relatively high power for their operation and has the advantage that the electronic circuitry of the signal receiving means does not have to be powered by the battery between adjustment operations. As a result, the life-time ' of the battery can be significantly prolonged. As an example, the signal transmitting means may be adapted to transmit electromagnetic wave signals and the energizer unit be adapted to draw radiant energy from .the electromagnetic wave signals, as they are transmitted to the signal receiving means, and to transfer the radiant energy into said current. The energizer unit suitably comprises a coil of the signal receiving means for inducing an alternating current as electromagnetic wave signals are transmitted through the coil and a rectifier for rectifying the alternating current. The rectified current is used for charging the rechargeable power source . Alternatively, the signal transmitting and receiving means may solely be used for control signals and further signal transmitting and receiving means be provided for transferring signal energy to implanted components. By such a double system of signal transmitting and receiving means the advantage is obtained that the two systems can be designed optimally for their respective purposes, namely to transmit control signals and to transfer energy from signals. The invention is described in more detail with reference to the accompanying drawings, in which Fig. 1A-D are block diagrams of four different principal embodiments of the food intake restriction device according to the invention. Fig. 2A-D are cross-sectional views of a pump mechanism according to Fig. 1C, which is designed to pump fluid in opposite directions by mechanically pushing a wall portion in only one direction. Fig. 3 is a cross-sectional view of a reservoir having a variable volume controlled by a remote control motor, in accordance with a particular embodiment of the principal embodiment shown in Fig. IB or 2B, . Fig. 4 is a cross-sectional view of a reservoir having a variable volume adjustable by manual manipulation, in accordance with a particular embodiment of the principal embodiment ' shown in Fig. IB or ID. Fig. 5A is a perspective view of a hydraulic, pneumatic or mechanical servo system in accordance with a particular embodiment of the principal embodiment shown in Fig. ID. Fig. 5B is a cross-sectional view taken along line VB-VB of Fig 5A . Fig. 6 is a block diagram illustrating remote control components of the device of the invention; Fig. 7 is a schematic view of exemplary circuitry used for the block diagram in Fig. 4; and Fig. 8 is a schematic view af a band with a cavity defining a restriction opening for use in accordance with the invention. Fig. 1A-D is a block diagram of four different embodiments of food intake restriction devices according to the invention. Fig. 1A shows a restriction member in the form of a typically conventional inflatable band 2 (SAGB) for providing a stoma opening in the stomach or esophagus, a separate reservoir 4, a one way pump 6 and an alternate valve 8. Fig. IB shows the band 2 and a fluid supply reservoir 10. Fig. 1C shows the band 2, a two way pump 12 and the reservoir 4. Fig. ID shows a servo system with a first closed system controlling a second system. The servo system comprises the fluid supply reservoir 10 and a servo reservoir 14. The servo reservoir 14 controls a larger adjustable reservoir 16 which in connection with the band 2 varies the volume of a cavity in the band, which in turn varies a restriction opening 3 in the band 2. Such a band 2 and opening 3 are illustrated schematically in Fig. 8. The conventional band 2 comprises an adustment means having an expandable ' /contractabe cavity 5 which is expanded or contracted by supplying hydraulic fluid (e.g. from reservoir 4, 6, 10, or 16) , and the band 2 may be sutured in place, illustrated schematically at 7 in Fig.8. Figs. 2A-D are cross-sectional views of a pump mechanism adapted to pump fluid in both directions only by mechanically pushing a separate sealing wall portion 18 in one direction. Fig. 2A shows a piston 20 pushed forwards against a spring 22 towards the wall portion 18 and located in a pump housing 24 conducting fluid from a right upper fluid passage 26 of the housing 24 to a left fluid passage 28 of the housing 24. A main valve 30 is open and a nonreturn valve 32 is closed. Fig. 2B illustrates the first pump movement in which the piston 20 has moved forwards and reaches the wall portion 18. Fig. 2C illustrates how the piston 20 moves backwards by the action of the spring 22. The main valve 30 is now closed and the nonreturn valve 32 is open for fluid from the right upper passage 26. Fig. ID illustrates how the piston 20 is moved ■ further downwards from its position according to Fig. 2B while pushing the wall portion 18 downwardly against a second spring 34 that is stronger than spring 22, whereby fluid escapes from a right lower fluid passage 36. When moving the piston 20 backwardly from the position according to Fig. 2D, fluid enters the left fluid passage 28 and a valve 38 in the lower right fluid passage 36 closes. Fig. 3 is a cross-sectional view of a reservoir 40 defining a chamber 42, the size of which is variable and is controlled by a remote controlled electric motor 44, in accordance with Fig. IB or ID. The reservoir 40 and the motor 44 are placed in a housing 46. The chamber 42 is varied by moving a large wall 48. The wall 48 is secured to a nut 50, which is threaded on a rotatable spindle 52. The spindle 52 is rotated by the motor 44 via an angular gearing, which comprises two conical gear wheels 54 and 56 in mesh with each other. The motor 44 is powered by a battery 58 placed in the housing 46. An signal receiving means 60 for controlling the motor 44 is also placed in the housing 46. Alternatively, the battery 58 and the signal receiving means 60 may be mounted in a separate place. The motor 44 may also be powered by energy transferred from transmitted signals. Fig. 4 is a cross-sectional view of a reservoir 62 defining a chamber 64, the size of which is variable and is controlled by manual manipulation. A gable wall portion 66 of an open ended inner cylindrical housing 68 is adapted to be pushed downwards to fit in a desired locking groove 70 of a plurality of locking grooves 70 on the mantle wall of he cylindrical housing 68, to reduce the size of the chamber 64. The inner cylindrical housing 68 is suspended by springs 72 and is telescopically applied on an outer cylindrical housing 74. When pushing the inner cylindrical housing 68 it moves downwards relative to the outer cylindrical housing 74 causing the gable wall portion 66 to release from the locking groove 70 and move upwards relative to the inner cylindrical housing 68. When the inner housing 68 is moved upwardly by the action of the springs 72 the size of the chamber 64 is increased. ' Figs. 5A and 5B show a servo means comprising a main ring- shaped fluid reservoir 76 defining a chamber 78, the size of which is variable. Centrally positioned in the main ring-shaped reservoir 76 there is a servo fluid reservoir 80 defining a chamber 82, the size of which is variable. The chamber 82 of the servo reservoir 80 is substantially smaller than the chamber 78 of the main reservoir 76. The two reservoirs 76 and 80 are situated between two opposite separate walls 84 and '86, and are secured thereto. When changing the amount of fluid in the servo reservoir 80, the two opposite walls 84,86 are moved towards or away from each other, whereby the size of the chamber 78 of the main reservoir 76 is changed. Fig. 6 shows the basic parts of a remote control system of the device of the invention including the electric motor 44 of the embodiment shown in Fig. 3. In this case, the remote control system is based on the transmission of electromagnetic wave signals, often of high frequencies in the order of 100 kHz - 1 gHz, through the skin 130 of the patient. In Fig.6, all parts placed to the left of the skin 130 are located outside the patient's body and all parts placed to the right of the skin 130 are implanted. Any suitable remote control system may be used. An external signal transmitting antenna 132 is to be positioned close to a signal receiving antenna 134 implanted close to the skin 130. As an alternative, the receiving antenna 134 may be placed for example inside the abdomen of the patient. The receiving antenna 134 comprises a coil, approximately 1-100 mm, preferably 25 mm in diameter, wound with a very thin wire and tuned with a capacitor to a specific high frequency. A small coil is chosen if it is to be implanted under the skin of the patient and a large coil is chosen if it is to be implanted in the abdomen of the patient. The transmitting antenna 132 comprises a coil having about the same size as the coil of the receiving antenna 134 but wound with a thick wire that can handle the larger currents that is necessary. The coil of the transmitting antenna 132 is tuned to the same specific high frequency as the coil of the receiving antenna 134. An external control unit 136 comprises a microprocessor, a high frequency electromagnetic wave signal generator and a power amplifier. The microprocessor of the control unit 136 is adapted to switch the generator on/off and to modulate signals generated by the generator to send digital information via the power amplifier and the antennas 132,134 to an implanted control unit 138. To avoid that accidental random high frequency fields trigger control commands, digital signal codes are used. A conventional keypad placed on the external control unit 136 is connected to the microprocessor thereof. The keypad is used to order the microprocessor to send digital signals to either increase or decrease the size of the restriction opening defined by the loop of the restriction member 2. The microprocessor starts a command by applying a high frequency signal on the antenna 132. After a short time, when the signal has energized the implanted parts of the control system, commands are sent to increase or decrease the size of said restriction opening of the restriction member 2 in predefined steps. The commands are sent as digital packets in the form illustrated below. Start pattern, Command, Count , Checksum, 8 bits 8 bits 8 bits 8 bits The commands are sent continuously during a rather long time period (e.g. about 30 seconds or more) . When a new increase or decrease step is desired the Count byte is increased by one to allow the implanted control unit 138 to decode and understand that another step is demanded by the external control unit 136. If any part of the digital packet is erroneous, its content is simply ignored. Through a line 140, an implanted energizer unit 126 draws energy from the high frequency electromagnetic wave signals received by the receiving antenna 134. The energizer unit 126 stores the energy in a power supply, such as a large capacitor, powers the control unit 138 and powers the electric motor ' 44 via a line 142. The control unit 138 comprises a demodulator and a microprocessor. The demodulator demodulates digital signals sent from the external control unit 136. The microprocessor of the control unit 138 receives the digital packet, decodes it and, provided that the power supply of the energizer unit 126 has sufficient energy stored, sends a signal via a signal line 144 to the motor 44 to either increase or decrease the size of the restriction opening of the restriction member 2 depending on the received command code. Alternatively, the energy stored in the power supply of the energi-zer unit may only be used for powering a switch, and the energy for powering the motor 44 may be obtained from another implanted power source of relatively high capacity, for example a battery. In this case the switch is adapted to connect said battery to the control unit 138 in an "on" mode when said switch is powered by said power supply and to keep said battery disconnected from the control unit in a "standby" mode when said switch is unpowered. With reference to Fig. 7, the remote control system schematically described above will now be described in accordance with a more detailed embodiment . The external control unit 136 comprises a microprocessor 146, a signal generator .148 and a power amplifier 150 connected thereto. The microprocessor 146 is adapted to switch the signal generator 148 on/off and to modulate signals generated by the signal generator 148 with digital commands that are sent to implanted components of the food intake restriction device. The power amplifier 150 amplifies the signals and sends them to the external signal transmitting antenna 132. The antenna 132 is connected in parallel with a capacitor 152 to form a resonant circuit tuned to the frequency generated by the signal generator 148. The implanted signal receiving antenna coil 134 forms together with a capacitor 154 a resonant circuit that is tuned to the same frequency as the transmitting antenna 132. The signal receiving antenna coil 134 induces a current from the received high frequency electromagnetic waves and a rectifying diode 160 rectifies the induced current, which charges a storage capacitor 158. A coil 156 connected between the antenna coil 134 and the diode 160 prevents the capacitor 158 and ' the diode 160 from loading the circuit of the signal receiving antenna 134 at higher frequencies. Thus, the coil 156 makes it possible to charge the capacitor 158 and to transmit digital information using amplitude modulation. A capacitor 162 and a resistor 164 connected in parallel and a diode 166 forms a detector used to detect amplitude modulated digital information. A filter circuit is formed by a resistor 168 connected in series with a resistor 170 connected in series with a capacitor 172 connected in series with the resistor 168 via ground, and a capacitor 174, one terminal of which is connected between the resistors 168,170 and the other terminal of which is connected between the diode 166 and the circuit formed by the capacitor 162 and resistor 164. The filter circuit is used to filter out undesired low and high frequencies. The detected and filtered signals are fed to an implanted microprocessor 176 that decodes the digital information and controls the motor 44 via an H-bridge 178 comprising transistors 180,182,184 and 186. The motor 44 can be driven in two opposite directions by the H-bridge 178. The microprocessor 176 also monitors the amount of stored energy in the storage capacitor 158. Before sending signals to activate the motor 44, the microprocessor 176 checks whether the energy stored in the storage capacitor 158 is enough. If the stored energy is not enough to perform the requested operation, the microprocessor 176 waits for the received signals to charge the storage capacitor 158 before activating the motor 44. There are a number of conceivable alternative embodiments of the invention that give the same result as the above- described embodiments. For example, the microprocessor of the external and implanted, respectively, control units may be replaced by discrete components. The power amplifier of the external control unit may be omitted if the signals generated by the signal generator are strong enough. Therefore, the invention is to be accorded the broadest interpretation of the appended claims to encompass all equivalent structures and assemblies . One further advantage with this invention is that there may be a night button on the remote control setting the adjustment means in a position with a larger stoma diameter during the night, thus avoiding vomiting or nausa. - -»--'vmBTTE SHEE

Claims: CLAIMS 1. A food intake restriction device for forming a stoma opening in the stomach or esophagus of a patient, the device comprising an elongated restriction member (2) , forming means for forming the elongated restriction member into at least a substantially closed loop around the stomach or esophagus, said loop defining a restriction opening (3) , and an adjustment means (5) for adjusting the restriction member in said loop to change the size of the restriction opening, characterised in that implantable hydraulic operation means (6, 8 ; 10 ; 12 ; 10, 14 ; 76- 86) are provided for operating the adjustment means (5) in a non-invasive manner, and that an implantable reservoir (4,-10; 16) containing a predetermined amount of hydraulic fluid is provided, the hydraulic operation means being adapted to operate the adjustment means by using the hydraulic fluid of the reservoir. 2. The device according to claim 1, wherein the adjustment means comprises an expandable cavity (5) in the restriction member (2) , the size of the restriction opening (3) being reduced upon expansion of the cavity and increased upon contraction of the cavity, and the hydraulic operation means (6, 8; 10; 12 ; 10, 14 ; 76-86) are adapted to distribute hydraulic fluid from the reservoir (4,-10; 16) to expand the cavity, and to distribute hydraulic fluid from the cavity to the reservoir to contract the cavity, to thereby control the size of the restriction opening. 3. The device according to claim 2, wherein the reservoir (10) defines a chamber (42,-64) for said predetermined amount of fluid and the hydraulic operation means are adapted to change the size of the chamber. 4. The device according to claim 3, wherein the hydraulic operation means comprises first and second wall portions (48;66) of the reservoir (10), which are displaceable relative to each other to change the size of the chamber (42; 64) of the reservoir. 5. The device according to claim 4, wherein the first and second wall portions ( 66 ) of the reservoir are designed to be displaceable relative to each other by manual manipulation thereof . 6. The device according to claim 4, wherein the first and second wall portions of the reservoir (10) are displaceable relative to each other by magnetic means, hydraulic means, or electric control means. 7. The device according to claim 4, wherein the hydraulic operation means are adapted to distribute fluid from the reservoir (10) to the cavity (5) of the restriction member (2) in response to a predetermined first displacement of the first wall portion (48; 66) of the reservoir relative to the second wall portion of the reservoir and to distribute fluid from the cavity to the reservoir in response to a predetermined second displacement of the first wall portion relative to the second wall portion. 8. The device according to claim 2, wherein the hydraulic operation means comprise an activatable pump (6,12) adapted to pump fluid between the reservoir (4) and the cavity (5) of the restriction member (2) . 9. The device according to claim 8, wherein the pump comprises a first activation member for activating the pump to pump fluid from the reservoir (4) to the cavity (5) of the restriction member (2) and a second activation member for activating the pump to pump fluid from the cavity to the reservoir. 10. The device according to claim 9, wherein the first and second activation members are operable by manual manipulation thereof . ' 11. The device according to claim 9, wherein at least one of the activation members is adapted to operate when subjected to an external pressure exceeding a predetermined magnitude. 12. The device according to claim 9, wherein at least one of the first and second activating members are operable by magnetic means, hydraulic means, or electric control means. 13. The device according to claim 1, wherein the restriction member is non-inflatable, and the adjustment means is adapted to mechanically adjust the restriction member in said loop. 14. The device according to claim 2, wherein the hydraulic operation means comprise a servo means (10 , 14 ;44 , 50-56 ; 76-86) . 15. The device according to claim 14, wherein the hydraulic operation means comprise first and second wall portions of the reservoir (16 ;40 ; 62 ; 78) , and the servo means (10, 14 ;44 , 50- 56; 80-86) is adapted to provide relative displacement between the first and second wall portions of the reservoir to change the size of the chamber of the reservoir. 16. The device according to claim 15, wherein the servo means comprises magnetic means, or electric means. 17. The device according to claim 15, wherein the servo means comprises hydraulic means (10,14, 76-86). 18. The device according to claim 17, wherein the servo means comprises a servo reservoir defining a chamber containing servo fluid, and the hydraulic operation means comprise first and second wall portions of the servo reservoir, which are displaceable relative to each other to change the size of the chamber of the servo reservoir. 19. The device according to claim 18, wherein the first and second wall portions of the servo reservoir are designed to be displaceable relative to each other by manual manipulation thereof . 20. The device according to claim 18, wherein the first and second wall portions of the servo reservoir are displaceable relative to each other by magnetic means, hydraulic means, or electric control means. 21. The device according to claim 14, wherein the servo means comprises a servo reservoir (14) and a fluid supply reservoir (10) connected in a closed system and containing a further predetermined amount of fluid. 22. The device according to claim 21, wherein the fluid supply reservoir (10) defines a chamber for the further predetermined amount of fluid and the hydraulic operation means are adapted to change the size of the chamber and thereby control the amount of fluid in the servo reservoir (14) . 23. The device according to claim 22, wherein the fluid supply reservoir (10) comprises first and second wall portions, which are displaceable relative to each other to change the size of the chamber of the fluid supply reservoir. 24. The device according to claim 23, wherein the fluid supply reservoir (10) increases the amount of fluid in the servo reservoir (14) in response to a predetermined first displacement of the first wall portion of the fluid supply reservoir relative to the second wall portion of the fluid supply reservoir and decreases the amount of fluid in the servo reservoir in response to a predetermined second displacement of the first wall portion of the fluid supply reservoir relative to the second wall portion of the fluid supply reservoir. 25. The device according to any one of claims 1-24, further comprising a wireless remote control means (44,126,132-144) for non-invasively controlling the hydraulic operation means (6,8;10;12;10,14;76-86) . 26. The device according to claim 25, wherein the remote control means (44,126,132-144) comprises separate signal transmitting means (132,136) and implantable signal receiving means (134, 138) . 27. The device according to claim 26, wherein the signal receiving means (134,138) ' comprises a control unit (138) adapted to control the hydraulic operation means (6, 8; 10; 12; 10, 14; 76-86) in response to signals received from the signal transmitting means (132, 136). 28. The device according to claim 27, further comprising an implantable energizer unit (136) for providing energy to energy consuming components of of the device implanted in the patient. 29. The device according to claim 28, further comprising an implantable motor (44) for operating the hydraulic operation means (6, 8 ; 10; 12 ; 10, 14; 76-86) . 30. The device according to claim 29, wherein the control unit (138) is adapted to power the motor (44) with energy provided by the energizer unit (136) in response to signals received from the signal transmitting means (132,136). 31. The device according to claim 28, wherein the energizer unit (126) is adapted to transfer energy from the signals, as they are transmitted to the signal receiving means (134,138), into electric energy. 32. The device according to any of the preceding claims, wherein the forming means is adapted to form the restriction member (2) into a loop having a predetermined size. 33. The device according to claim 25, wherein the remote control means (44,126,132-144) comprises means for wireless transfer of energy from outside the patient's body to energy consuming implantable components of the device. 34. The device according to claim 33, further comprising an implantable motor (44) for operating the hydraulic operation means (6 ; 8; 10; 12; 10, 14,-76-86) , said means for wireless transfer of energy being adapted to directly power the motor with transferred energy. 35. The device according to claim 34, wherein the energy transferred by said means for transfer of energy comprises wave signals . 36. The device according to claim 34, wherein the energy transferred by said means for transfer of energy comprises an electric field or a magnetic field. 37. The device according to claim 1, wherein the adjustment means (5) is adapted to change the size of the restriction opening (3) such that the outer circumferential confinement surface of the restriction member (2) is changed. 38. The device according to claim 1, wherein the adjustment means (5) is adapted to change the size of the restriction opening (3) such that the outer circumferential confinement surface of the restriction member (2) is unchanged. 39. The device according to claim 26, wherein the signal transmitting means (132,136) and signal receiving means (134,138) are adapted to transmit and receive signals in the form of digital pulses. 40. The device according to claim 39, wherein the digital pulses comprise a magnetic field or an electric field. 41. The device according to any of claims 26 and 27, wherein the signal transmitting means (132,136) and signal receiving means (134,138) are adapted to transmit and receive wave signals . 42. The device according to claim 41, wherein the wave signals comprise electromagnetic waves, sound waves or carrier waves for remote control signals. 43. The device according to any of claims 28,31,33-36, wherein the energizer unit (136) is adapted to transfer the energy from the signals into direct or alternating current. 44. The device according to claim 25, wherein the remote control means (44,126,132-144) is capable of obtaining information on the size of the restriction opening (3) and to command the adjustment means (5) to adjust the restriction member (2) in response to obtained information.

Inventors: FORSELL PETER, FORSELL, PETER
Applicants: FORSELL PETER, FORSELL, PETER
Application year: 1999
Main classification: A61F5
IPC codes: A61F5