Closing system with electronic control

0001The present invention relates to a closure system with a suitable method for selectively opening and closing a tubular body organ.

0002From the <patcit id="pcit0001" dnum="DE4331658"><text>DE 43 31 658</text></patcit> An implantable device for selectively opening and closing tubular body organs is known, wherein an insertable into the tubular body member elongated valve body is provided. The valve body has a shut-off device, which can optionally be closed and released. For this purpose, the valve body has an elastic hose section, in which a inflatable body is arranged, which can be inflated by a fluid and then closes the lumen of the hose section. Both the opening and the closing is done by a manual handling, ie the inflation of the inflatable body is carried out by a manual operation of a pump and the opening is made by a manual actuation of a switch. In principle, however, care must be taken in the known system that the inflatable body is not inflated so much that on the one hand increases the body organ as a result of frequent opening and closing and expands, and on the other hand, the pressure generated by the inflatable body, the blood circulation of the body organ and would thus die off the tissue of the body organ. These specifications thus require that the closure of the body organ with the known system only within a limited pressure range is possible, however, resulting pressure peaks or short-term pressure loads or increases in the body organ, a secure closure of the body organ can not ensure, as the known system is not suitable to be tracked for a short time.

0003<patcit id="pcit0002" dnum="WO0150833A"><text>WO-A-01/50833</text></patcit> discloses a urinary incontinence treatment device having an adjustable restriction device for closing urethra urine passageway. A pressure sensor is implanted to receive the pressure on the throttling device, wherein a control unit controls the throttling device to release the urethra in response to the pressure sensor receiving an abnormally high pressure.

0004An object of the present invention is therefore to further develop the known closure system or the known method for selectively opening and closing a tubular body organ in such a way that pressure increases occurring in the body organ to be occluded are counteracted for a short time and a risk of necrosis is virtually ruled out.

0005Another object of the present invention is to provide a closure system which ensures continence at all times.

0006The objects are achieved with the features of claims 1 and 5.

0007According to the invention, the closure system for selectively opening and closing a tubular body member includes providing a closure member and a control system controlling the closure member, the control system adjusting a first state of the closure system and self-regulating a deviation from the first condition to the first condition. With this measure according to the application is achieved that at occurring pressure peaks or Coughing, sneezing, laughing or stooping can continue to perform the required functions of the closure system. With this measure according to the application, for example, when the closure system is stimulated at the urethra, a sphincter replacement system can be provided which replaces the function of the external sphincter of the urethra in adult human beings. The closure system according to the application can thus be used as an implantable adaptive fine-sensory sphincter replacement system. The fact that only a short time by pressure peaks a first state of the control system is left, the risk of necrosis is reduced or Nekroseerscheinungen can be prevented. With the closure system according to the application is thus avoided that a constant high closing pressure on the body organ or the urethra acts, causing the surrounding tissue of the body organ to necrosis or inflammation. Since the closure system according to the application provides a simply designed self-regulation, implantation into the human body is also harmless. In addition, it is possible to control the void manually by this easy-to-use closure system, whereby the control of the closure system is automatically possible by tapping the neurological signals directly to the nerve system of the body organ in the case of the urethra sphincter urethral using an artificial synapse , With the closure system according to the application, it is also possible that due to the simplicity of the closure system, the energy consumption is kept low and thus a long life is given. With the closure system according to the application, the patient obtains a high degree of quality of life by ensuring his continence with this implant and is not restricted in his range of action by the freedom of maintenance of the system.

0008Further advantageous embodiments of the present invention are the subject of the dependent claims.

0009If the control system with the closing element configured as a closed circuit, so a separate supply of the transmission medium, such as hydraulic fluid is not required.

0010With the features described, the self-regulating closure system is implemented in a simple manner, so that the closure system as such is easy to implant and has only a low energy consumption. The self-regulation is achieved in particular by the mutual opening and closing of the shut-off valves. At this point, however, it should be noted that in place of the pumping device and first shut-off valve also a fast-switching pump or fast switching actuator can be used.

0011In order to set the best possible self-regulation depending on the body organ, ie the closing pressure is maintained at a certain threshold and in this regard, a corresponding working pressure can be adjusted, so different sensor elements are provided, which optimally brings about the self-regulating action at suitable positioning =.

0012Further advantageous embodiments are the subject of the remaining dependent claims.

0013Reference to the following drawing, a preferred embodiment of the subject of the application will be described.

0014In <figref idref="f0001">Fig. 1A</figref> the closure system is shown, which in this case selectively opens and closes a urethra as body organ. In the closure system according to the application, the urethra has a closure element 1, which in this embodiment can be hydraulically actuated. On this occasion, it is pointed out that any other control is also conceivable. To the closing element 1 is a control system 3, in this case hydraulically connected. The control system 3 serves to set a first state of the closure system, for example a closed state of the closure element 1. For this purpose, the control system 3 in the hydraulic embodiment, a first reservoir 5, via a pumping device 7 to build a certain pressure, so-called closing pressure on the closing element 1. The connecting line arriving at the closing element is divided into a first feed line Z1 and a second feed line Z2, wherein the first feed line has the pumping device 7 and preferably a first shut-off valve V1 and the second feedline has a second shut-off valve V2, wherein both the first feed line and Also, the second supply line is connected to the first reservoir 5. Conventionally, the closure system according to the application can also be used merely as a device for selectively opening and closing a body organ, in this case the urethra. For operating the selective opening and closing, it is advantageous if the pumping device 7, the first shut-off valve V1 and the second shut-off valve V2 are connected to a control unit 11, which takes over the conventional opening and closing of the closing element 1. The closure system according to the application further comprises a first sensor unit S1, which is preferably provided upstream of the closing element 1 of the tubular body member, a second sensor unit S2 which measures the pressure in the connecting line and a third sensor unit S3 on the pumping device 7. This makes a differential pressure measurement possible.

0015The lock system according to the application now works according to the following functional principle.

0016The pump device 7 uses from the reservoir 5 as a food supply and generates a closing pressure on the closing element 1, which is selected such that the closing pressure seals the body organ via the closing element, but does not affect the blood supply to the body organ. The closing pressure corresponds to a pressure range that depends on different parameters, such. As body organ, vessel thickness, blood flow, etc. is dependent.

0017In a short-term pressure increase in the body organ, for example in the urethra in the bladder by coughing, sneezing, laughing or other effort, the closing pressure is not sufficient and the flow in the body organ would take place briefly. For this case, it is advantageous if the closing pressure also increases briefly, so as to continue to maintain the tightness of the body organ. However, the short-term increase in the closing pressure caused by the closure system according to the application does not lead to necrosis formation, ie the circulation of the body organ is influenced only briefly and is thus not harmful to the body organ. In order to maintain this mechanism, it is necessary that the control system 3 has different pressure ranges. In the embodiment shown in FIG. 1A, the pump device 7, which is designed, for example, as a fast-switching pump or as a fast actuator, generates the required closing pressure via the first shut-off valve V1. For this purpose, the second shut-off valve V2 must be closed. Upon reaching the closing pressure, the first shut-off valve V1 is closed, wherein the pump device 7 builds up to the first shut-off valve V1 increased compared to the closing pressure working pressure. If the flow through the body organ is carried out with the closing element, then only the second shut-off valve V 2 must be opened in order to reduce the closing pressure via the reservoir 5. But now occur upstream of the closing element 1 pressure peaks or short-term sustained pressure loads, so are registered with the sensor device S1 or detected and passed on to the control unit 11. The control unit 11 opens the first shut-off valve V1 almost simultaneously, so that the increased working pressure acts on the closing element 1 and thus ensures, for a short time, that the body organ is also sealed against the pressure peaks. In this case, it is conceivable that, depending on the perfusion function of the body organ, the control unit 11 closes the first shut-off valve again after a time constant and opens the second shut-off valve in order to reduce it to the required closing pressure from the increased working pressure. At the same time or in the meantime, the pump device 7 can again build up an increased working pressure, which is applied to the first working valve V1, and thus prepare for a second process.

0018In this way, according to the application, the control system 3 is thus capable of a first state of the closure system, which is conventionally to be compared with the closing of the body organ via the closing element 1 via the selective opening, a deviation from the first state self-regulating to the first state due. This measure ensures that the closure system fulfills the task placed on the closure system in any situation, including in the case of strains such as coughing or sneezing. Since the closing pressure by means of a fine-sensory control the prevailing in the body organ upstream pressure or Adjusted for bladder pressure in the bladder, necrosis is prevented, which is usually caused by a constant high closing pressure, which suppresses the blood circulation of the body organ and thus causes long-term damage.

0019At this point, it should again be emphasized that as in <figref idref="f0001">Figure 1A</figref> is shown, the pump device 7 can also be replaced by a normal pump in conjunction with a second reservoir R2 and a third shut-off valve V3. In this case, the increased compared to the closing pressure working pressure is achieved in that the pump is applied to open the third shut-off valve, the reservoir R2 to the required working pressure, then the third shut-off valve V3 is then closed. With this measure, it is achieved that the use of a fast-switching pump is not required, since the short-term loading of the closing element 1 is applied to the closing element when pressure peaks occur above the working pressure built up in the second reservoir R2 by opening the first shut-off valve.

0020Basically, it should be noted that the sensor elements are not only considered as pressure sensors, but also with capacitive or inductive sensors, the pressure can be determined, as well as volume changes can be measured via ultrasound or strain gauges, or a change in distance, which results in pressure increase, measured with light.

0021The invention relates to a system for the electronic control of an artificial fine-sensory sphincter implant. By means of this invention, the advanced system of an artificial sphincter implant extended by a fine sensor system and an actuator system is to be controlled in such a way that both complete continence can be ensured and at the same time the risk of necrosis caused by excessive and overly long pressure on the natural urethra minimized.

0022The prerequisite for this is an intelligent electronic control which recognizes various stress situations and avoids incontinence during dynamic stress such as coughing or laughing by increasing the cuff pressure and at the same time ensures adequate blood circulation of the urethral tissue by appropriate pressure reductions at rest. Since these electronic circuits are used in a medical implant, they must meet certain requirements such as long-term reliability, minimum power consumption, small physical dimensions, and individual adaptability.

0023This immediately results in the further object of the invention.

0024The invention further provides a system for electronically controlling an artificial fine sensory sphincter implant.

0025Further advantageous and / or preferred embodiments of the invention are the subject of the dependent claims.

0026In the following, this aspect of the invention will be described in more detail by way of example only and not limitation and with reference to the figures as well as advantageous and / or preferred embodiments.

0027The meanings of the reference numerals used are given in the following list. The terms signal and value are used synonymously here.<ol id="ol0001" compact="compact"><li>(1) differential pressure signal, pressure difference bubble cuff</li><li>(2) Monostable threshold signal, safety threshold</li><li>(3) Bistable threshold signal, normal pressure threshold</li><li>(4) cuff pressure</li><li>(5) Monostable reference signal, integration zero offset</li><li>(6) Monostable threshold signal, integration threshold</li><li>(7) Pre-pressure signal</li><li>(8) Monostable threshold signal, pre-pressure threshold</li><li>(9) Dynamic load</li><li>(10) Monostable threshold signal, pressure equalization threshold</li><li>(11) Bubble pressure</li><li>(12) Output value of the adder function, lower threshold</li><li>(13) Output signal or output value of the integrator function</li><li>(14) Output signal or output value of the differentiator function</li><li>(15) Increasing the cuff pressure</li><li>(16) Lowering the cuff pressure</li><li>(17) Form</li><li>(18) Increase of the form</li><li>(19) Output signal of the integrator function of the delay block</li><li>(20) Dynamic load</li><li>(21) Area of ​​backward integration</li><li>(22) Area of ​​continuous integration</li><li>(23) Method for regulating urethral closure pressure by means of an inflatable cuff, a fluid reservoir, a pump and a valve via hydraulic connections</li><li>(24) Hydraulic connection</li><li>(25) Cuff</li><li>(26) Controllable valve</li><li>(27) Bidirectional pump</li><li>(28) fluid reservoir</li><li>(29) Pre-pressure tank</li><li>(30) Method for regulating the urethral closure pressure by means of an inflatable cuff, a fluid reservoir, a pump, three valves and a pre-pressure container via hydraulic connections</li><li>(31) Urethra closure pressure</li><li>(32) Differentiator function</li><li>(33) adder function</li><li>(34) integrator function</li><li>(35) Parameter variation</li><li>(36) Comparator member</li><li>(37) Integrator function of the delay block</li></ol>

From the figures show

0028<ul id="ul0001" list-style="none"><li><figref idref="f0002">Fig. 1B</figref>FIG. 2: a schematic functional block diagram without a pre-pressurized container and with the output signal of the differentiator function as input signal of the integrator function, FIG.</li><li><figref idref="f0003">Fig. 2</figref>FIG. 2 is a schematic functional block diagram without a pre-pressurized container and with the output signal of the adder function as input signal of the integrator function, FIG.</li><li><figref idref="f0004">Fig. 3</figref>: a schematic functional block diagram with pre-pressure vessel and with the output signal of the differentiator function as input signal of the integrator function,</li><li><figref idref="f0005">Fig. 4</figref>FIG. 2 is a schematic functional block diagram with pre-pressurized containers and with the output signal of the adder function as input signal of the integrator function, FIG.</li><li><figref idref="f0006">Fig. 5a</figref> = <figref idref="f0008">Fig. 7a</figref>: in the case of sustained dynamic stress, the course of pressure in the cuff and in the bladder during short-term dynamic loading,</li><li><figref idref="f0006">Fig. 5b</figref> = <figref idref="f0008">Fig. 7b</figref>: with continuous dynamic load the signal curve of the electronic circuit with short-term dynamic load,</li><li><figref idref="f0006">Fig. 5c</figref> = <figref idref="f0008">Fig. 7c</figref>in the case of a continuous dynamic load, the signal course of the integrator system with the output signal of the differentiator function as input signal of the integrator function with short-term dynamic load,</li><li><figref idref="f0006">Fig. 5d</figref> = <figref idref="f0008">Fig. 7d</figref>in the case of a continuous dynamic load, the signal course of the integrator system with the output signal of the adder function as input signal of the integrator function with short-term dynamic load,</li><li><figref idref="f0006">Fig. 5e</figref> = <figref idref="f0008">Fig. 7e</figref>: with continuous dynamic load, the switching states for pressure increase and pressure reduction in the cuff at short-term dynamic load,</li><li><figref idref="f0007">Fig. 6a</figref> = <figref idref="f0009">Fig. 8a</figref>: in the case of sustained dynamic load, the course of pressure in the cuff, in the bladder and in the pre-pressure vessel during short-term dynamic loading,</li><li><figref idref="f0007">Fig. 6b</figref> = <figref idref="f0009">Fig. 8b</figref>: with continuous dynamic load the signal curve of the electronic circuit with short-term dynamic load,</li><li><figref idref="f0007">Fig. 6c</figref> = 8c: with continuous dynamic load the signal course of the integrator system with the output signal of the differentiator function as input signal of the integrator function with short-term dynamic load,</li><li><figref idref="f0007">Fig. 6d</figref> = <figref idref="f0009">Fig. 8d</figref>in the case of a continuous dynamic load, the signal course of the integrator system with the output signal of the adder function as input signal of the integrator function with short-term dynamic load,</li><li><figref idref="f0007">Fig. 6e</figref> = <figref idref="f0009">Fig. 8e</figref>: with continuous dynamic load the switching states of the pressure increase and pressure reduction in the cuff with short-term dynamic load,</li><li><figref idref="f0007">Fig. 6f</figref> = <figref idref="f0009">Fig. 8f</figref>in the case of continuous dynamic load, the switching states of the pressure increase in the admission pressure vessel,</li><li><figref idref="f0007">Fig. 6g</figref> = <figref idref="f0009">Fig. 8g</figref>in the case of continuous dynamic loading, the course of the integrator signal for controlling the opening of the valve between the cuff and the admission pressure vessel,</li><li><figref idref="f0010">Fig. 9a</figref>: the integrator signal with switching threshold with continuous dynamic load,</li><li><figref idref="f0010">Fig. 9b</figref>the input signals of the integrator function with regions of continuous (22) and return (21) integration with continuous dynamic loading,</li><li><figref idref="f0011">Fig. 10</figref>: the method for the regulation of the urethra occlusion pressure without pre-pressure container,</li><li><figref idref="f0012">Fig. 11</figref>: the method for the regulation of the urethra occlusion pressure with pre-pressure container,</li><li><figref idref="f0013">Fig. 12</figref> the dynamic load waveform, namely 12a absolute pressures, 12b the urethane closure pressure signal with switching thresholds, and 12c the switching threshold integrator signal (or integrator element)</li><li><figref idref="f0014">Fig. 13</figref> a functional schematic representation of the artificial sphincter implant.</li><li>The electronic control of the sphincter implant can be realized both digitally and analogously. The method for controlling the sphincter implant, which is the subject of this invention, does not change in principle with it.</li><li>The patient is given the opportunity, by means of variable parameters, to adapt the behavior of the implant individually to his personal requirements. In analogue control, D / A converters are used for parameter variation, the clock signal of which can be generated externally and transmitted via telemetry.</li></ul>

How the electronic control works

0029The electronic control, which is the subject of this invention, converts signals of the fine sensor system, in particular the differential pressure between urinary bladder and cuff or a comparable differential pressure, into control commands to the actuators of the implant.

0030The sensor signals applied to the signal inputs are amplified by means of amplifier circuits in such a way that, during operation, the signals move between the limit values ​​predetermined by the circuit.

0031In operation without dynamic load, such as when sitting or lying quietly, the cuff pressure (4) moves in an area in which the circulation of the urethral tissue is guaranteed, but could easily lead to incontinence in increasing the intraocular pressure (11). If the differential pressure signal or the differential pressure value (1) rises, the cuff pressure (4) is lowered when a bistable threshold value (3) is reached (16), the differential pressure signal or pressure drops below the differential pressure value (1) the lowered bistable threshold (3), the reduction (16) of the cuff pressure (4) is terminated. This is done in the analog variant by means of a comparator function, which is provided with a hysteresis circuit.

0032When dynamic loading occurs, the actuators must take on the function of a healthy sphincter, namely by active pressure transmission, thus avoiding the involuntary contraction of the sphincter under dynamic load incontinence. In case of sudden pressure increase, such as coughing or laughing, the cuff pressure (4) must be increased within milliseconds. As can be assumed at a differential pressure of zero incontinence, when falling below the differential pressure signal or the differential pressure value (1) below a threshold different from zero, the actuator to increase (15) of the cuff (4) causes. In order to prevent a certain inertia of the actuator beyond, is provided in the electronic control, this lower threshold value, the differential pressure signal or the differential pressure value (1) may only fall short of micturition, to equip it with an additive, active component. In order to achieve this, in the analog variant the differential pressure signal (1) is differentiated by means of a differentiator circuit and the output signal or the output value (14) of the differentiator function is raised by the lower threshold value by means of an adder circuit. When using a microprocessor, the sensor signal is numerically differentiated by subtracting from the next to last signal value the current signal value and, if positive, adding the result to an offset component. The result serves as the lower threshold (12). By these measures it is achieved that the lower threshold value (12) for sudden increase of the internal bubble pressure (11) the falling differential pressure signal or counteracts the differential pressure value (1) and thus allows early activation of the actuators. Activation of the actuator system takes place in the analog variant by means of a comparator, which compares the differential pressure signal (1) with the lower threshold value (12).

0033As soon as the actuator is activated by falling below the differential pressure signal (1) below the lower threshold value (12), in the analog variant the comparator function is deactivated in unloaded operation to avoid an excessive cuff pressure (4) and the cuff pressure (4) is increased to a value, can be ensured in the continence, but the circulation of the affected Urethragewebes may be impaired.

0034This pressure increase can, depending on the design of the actuators, take place in different ways:<ul id="ul0002" list-style="none" compact="compact"><li>When using a pre-pressure container (29), a valve (26) is opened, so that a pressure equalization between the pre-pressure container (29) and the cuff (25) can take place. Due to the fluid flow in this pressure equalization, the pre-set pressure (17) set previously must be higher than the desired maximum cuff pressure by a certain amount, depending on the design of the cuff (25) and the pre-pressure tank (29). The opening of the valve between pre-pressure container (29) and cuff (25) is timed. In this case, in the case of the analog variant, in particular an integrator element can be used which is started simultaneously with the opening of the valve and whose output signal (19) is compared with a monostable threshold value (10) by means of a comparator element. When parity is reached, the valve (26) is closed again between admission pressure vessel (29) and cuff (25) and at the same time the elevation (18) of the admission pressure (17) in the admission pressure vessel (29) is started. The activation of the integrator member, which controls the reduction (16) of the cuff pressure (25) in the analog variant, takes place either simultaneously with the opening or with the closing of the valve (26) between admission pressure vessel (29) and cuff (25). The signal that causes the valve (26) between the admission pressure container (29) and cuff (25) to close, triggers the increase (18) of the Vorwerk (17) in the pre-pressure container (29). The pressure signal of the form (17), which is additionally required when using a pre-pressure container (29) is compared in the analog variant by means of a comparator with a monostable threshold (8) and at parity, a signal is triggered, which Termination of the increase (18) of the form (17) causes. When using a microprocessor, this is programmed so that it behaves in principle as the analog circuit described.</li></ul>

0035In differently designed actuators without form-container (29) the achievement of this safety pressure is registered with a comparator or a comparator that compares the differential pressure signal or the differential pressure value (1) with a monostable threshold (2) and when the differential pressure signal is exceeded or of the differential pressure value (1) via this threshold (2) triggers a signal that causes the actuators to terminate the increase (15) of the cuff pressure (4). This signal also activates the integrator element or the integrator function, which controls the depression (16) of the cuff pressure (4).

0036The activation of the integrator element, which controls the reduction (16) of the cuff pressure (4) in the analog variant, can take place in particular via the interruption of a discharge circuit of the capacitor counter-coupled to the operational amplifier of the integrator element. Thus, integration can take place and start value is equal to the voltage across the discharged capacitor.

0037The intelligent behavior of the electronic control is particularly evident in the fact that with continuous dynamic load, the reduction (16) of the cuff pressure (4) is delayed. In the case of the analog variant, an integrator element is used for this purpose. By a suitable choice of the input signals is achieved that at short-term load, for example when getting up from a sitting position, the cuff pressure (4) is quickly reduced again to levels that correspond to safe normal operation without risk of necrosis. On the other hand, with continuous dynamic load, for example during physical activities, the cuff pressure (4) is maintained at the high level until the dynamic load subsides. This behavior is produced in the analog variant in that two suitable signals are present at the inverting and at the non-inverting input of the operational amplifier of the integrator element. On the one hand, this is a signal analogous to the output signal (14) of the differentator element, in particular either the output signal (14) of the differentiator element itself or the output signal (12) of the adder element. At the other input of the operational amplifier of the integrator member is a monostable reference signal (5). This monostable reference signal (5) is chosen such that it can be crossed by the voltage applied to the other input of the operational amplifier of the integrator element signal under dynamic load and thus volatile output signal (14) of the differentator. This wiring of the integrator member has the consequence that the output signal (13) of the integrator member away from the starting point when the input signal (14) of the differentiator analog input signal has not or rarely crossed the monostable reference signal (5), ie at low dynamics of the load , On the other hand, if the dynamics of the load are high, the input signal analogous to the output signal (14) of the differentiator element frequently crosses the monostable reference signal (5). As soon as the input signal analogous to the output signal (14) of the differentiator element has crossed the monostable reference signal (5), the output signal (13) of the integrator element moves to the starting value. At high dynamics of the load thus the output signal (13) of the integrator member is driven zigzag against the starting value. In the analog variant, the output signal (13) of the integrator element is compared by a comparator element with a constant threshold value (6) which may not be close to the starting value of the output signal (13) of the integrator element. As soon as the output signal (13) of the integrator element reaches this constant threshold value (6), the lowering (16) of the cuff pressure (4) is initiated. This reduction takes place by the activation of the comparator element, which causes the actuators to lower (16) the cuff pressure (4) until the differential pressure signal (1) falls below the lowered bistable threshold signal (3). The cuff pressure (4) is now back in a safe area where the risk of necrosis is minimal. If a microprocessor is used, this numerically performs the same calculations in principle as the analog circuit and thus produces a comparable behavior.

0038Another key feature of this electronic control is the presence of numerous possibilities to influence the behavior of the system by varying parameters from the outside. Thus, the artificial fine-sensory sphincter implant can be adapted to the individual requirements of the patient, on the one hand, the setting of parameters after completion of scarring after implantation, on the other hand with changing requirements by the patient, for example, with advancing age or the change in living habits.

0039Since, in contrast to the digital one, one must limit the number of variable parameters in the analog variant, four parameters have been selected for the variation, which can decisively influence the behavior of the implant.

The monostable offset signal

0040The monostable offset signal is the additive component which supplements the output signal (14) of the differentiator element to the lower switching threshold. By varying the monostable offset signal too slow an actuator or a premature urine flow can be compensated.

The bistable threshold signal (3)

0041The bistable threshold signal (3) can be varied if the cuff pressure (4) during normal operation already reaches critical values ​​for the blood circulation of the urethral tissue or if the bistable threshold signal (3) is set so low that the lowering (16) of the cuff pressure ( 4) is caused inappropriately frequently.

The monostable reference signal (5)

0042By varying the monostable reference signal (5), the speed of integration can be adjusted.

The monostable threshold signal (2)

0043The monostable threshold signal (2) corresponds to the differential pressure signal or the differential pressure value (1), in which the cuff pressure (4) has a value at which ensures continence, but the circulation of the urethral tissue is impaired. If the monostable threshold signal (2) is too low, despite increased cuff pressure (4) at high dynamic load, the differential pressure signal or the differential pressure unit (1) fall below the lower threshold and thus trigger a further Duckerhöhung. If the monostable threshold signal (2) is set too high, the urethral tissue may be damaged as a result of the high cuff pressure (4) or

The monostable threshold signal (8)

0044By varying the monostable threshold signal (8), the admission pressure in the admission pressure vessel and thus the maximum cuff pressure (4) after pressure equalization is set.

0045If a microprocessor is used, you have a lot more possibilities to influence the behavior right from the beginning to the complete reprogramming.

The procedures for the regulation of the cuff pressure

0046The actuators controlled by the described analog circuit can use various methods and arrangements to produce the desired influence on the urethra. The different arrangements and components of the actuators require an adapted control electronics. Two hydraulic methods are described below by way of example, one with and one without pre-pressure container (29).

0047With regard to the method for regulating the cuff pressure (4) by means of a pump (27), a valve (26) and a fluid reservoir (28) via hydraulic connections (24), see <figref idref="f0011">Fig. 10</figref>.

0048In this method for regulating the cuff pressure (4), the use of a pump (27) is provided, which oppose the hydraulic flow at a standstill low resistance. When the valve (26) for lowering (16) of the cuff pressure (4) is opened, a pressure equalization takes place between the cuff (25) and the fluid reservoir (28). The valve (26) can be placed between the cuff (25) and the pump (27) as well as between the pump (27) and the fluid reservoir (28).

0049With regard to the method for regulating the cuff pressure (4) by means of a pump (27), a pre-pressure container (29), three valves (26) and a fluid reservoir (28) via hydraulic connections (24), see <figref idref="f0012">Fig. 11</figref>.

0050The use of a pre-pressure container (29) in this method allows a flash-like increase (15) of the cuff pressure (4). However, another pressure sensor is needed, which controls the regulation of the form (17). After triggering the increase (15) of the cuff pressure (4), a pressure equalization is made possible by opening the valve (26) between the admission pressure vessel (29) and the cuff (25). The security pressure in the cuff (25) thus depends only on the previously set in the form-container (29) form (17). Decisive for the pressure equalization is also the construction of the pre-pressure container (29). The smaller the dimensions, the larger the form (17) must be.

0051Since to increase (18) of the form (17) the period after increasing (15) of the cuff (4) is used, so for a certain period no further increase (15) of the cuff (4) can be triggered, must in the selection the pump (27) no high demands are placed on speed. The operation at low voltages is thereby made possible.

The micturition control

0052To initiate the micturition, a signal is generated externally. This signal causes the actuator to decrease (16) of the cuff (4) and also disables the analog electronic circuit except for the comparator, which limits the Cuffnormaldruck up.

0053After completion of the micturition, a second external signal is generated, which again initiates the increase (15) of the cuff pressure (4). The cuff pressure (4) is increased until the differential pressure signal or the differential pressure value (1) reaches the bistable threshold value (3). A comparator reactivates the rest of the analog electronic circuitry.

0054In summary, this aspect of the invention thus comprises the following embodiments:<ul id="ul0003" list-style="none"><li>According to Embodiment 1, the system for electronically controlling an artificial fine-sensory sphincter implant <b>characterized in that</b> the behavior of at least one sensor signal in an analog or digital electronic circuit is converted by means of arithmetic and comparator functions and compared with reference values ​​such that an actuator system is controlled such that the cuff pressure or the differential pressure between the cuff and the bladder is either in one of two threshold values limited low range moves or above a certain security pressure.</li><li>According to the embodiment form, which represents the invention together with Embodiment 1, the sensor signal or the sensor value (1) of the electronic circuit according to Embodiment 1 <b>characterized in that</b> it behaves analogously to the difference between internal bladder pressure (11) and cuff pressure (4).</li><li>According to Embodiment 3, the differentiator function of the electronic circuit according to Embodiment 1 <b>characterized in that</b> the output signal or the output value (14) of the differentiator function corresponds to the differentiation of the course of the sensor signal (1) according to embodiment 2.</li><li>According to Embodiment 4, the adder function is a monostable offset signal of the electronic circuit according to Embodiment 1 <b>characterized in that</b> the output signal or the output value (12) of the adder function corresponds to the output signal or output value (14) of the differentiator function according to embodiment 3, which is increased by a monostable offset signal or a monostable offset value.</li><li>According to Embodiment 5, the comparator function is a bistable threshold signal (3) of the electronic circuit according to Embodiment 1 <b>characterized in that</b> in the case of parity or the crossing of the sensor signal or sensor value (1) according to embodiment 2 with the bistable threshold signal or the bistable threshold value (3), this threshold signal or threshold value (3) is lowered by the amount caused by the hysteresis is raised and a signal is triggered, which causes the actuators to decrease (16) of the cuff (4) until such time as by repeated parity or Repeated crossing of the sensor signal (1) according to embodiment 2 with the bistable threshold signal or the bistable threshold (3) a signal is triggered, which causes the actuator to terminate the lowering (16) of the cuff (4) and the bistable threshold signal or the bistable threshold (3) by the amount due to the hysteresis increases or decreases.</li><li>According to Embodiment 6, the comparator function of the electronic circuit according to Embodiment 1 is FIG <b>characterized in that</b> the sensor signal or the sensor value (1) according to embodiment 2 is compared with the output signal or the output value (12) of the adder function according to embodiment 4 such that in the case of the parity or the crossing of the sensor signal or the sensor value (1) according to embodiment 2 with the output signal or the output value (12) of the adder function according to embodiment 4, a signal is triggered, which causes the actuators to increase (15) of the cuff pressure (4) and overrides the comparator function according to embodiment 5.</li><li>According to Embodiment 7, the integrator function is a monostable reference signal or a monostable reference value (5) and a constant starting value of the electronic circuit according to Embodiment 1 <b>characterized in that</b> optionally<ul id="ul0004" list-style="none"><li>a) the monostable reference signal or the monostable reference value (5) is unequal to the monostable offset signal or embodiment 4 and is chosen such that the output signal or the output value (12) of the adder function according to embodiment 4 in activity the monostable reference signal or crosses the monostable reference value (5), and that the integrator function the difference between the output signal and the output value (12) of the adder function according to embodiment 4 and the monostable reference signal or the monostable reference value (5) is continuously or numerically integrated in such a way that the output signal or output value (14) of the differentiator function according to embodiment 3 is low ., the output value (13) of the integrator function removed from the starting value and at high activity of the output signal or of the output value (14) of the differentiator function according to embodiment 3 is moved to the starting value, see FIGS. 1 d, 2 d, 3d, 4d and <figref idref="f0006">Fig. 5</figref>, or</li><li>b) the monostable reference signal or the monostable reference value (5) is not equal to the output signal (14) of the differentiator function according to embodiment 3 at low activity and is selected such that the output signal or the output value (14) of the differentiator function according to embodiment 3 in activity crosses the monostable reference signal or the monostable reference value (5), and that the integrator function, the difference between the output signal or the output value (14) of the differentiator function according to embodiment 3 and the monostable reference signal or the monostable reference value (5) continuously or numerically integrated in such a way that the output signal or output signal (14) of the differentiator function according to embodiment 3 is low ., the output value (13) of the integrator function continuously removed from the starting value and at high activity of the output signal or of the output value (14) of the differentiator function according to embodiment 3 is moved to the starting value, see FIGS. 1c, 2c, 3c, 4c and 4c <figref idref="f0006">Fig. 5</figref>.</li></ul></li><li>According to embodiment 8, the delay function of the electronic circuit according to embodiment 1 when using a method for regulating the cuff pressure (4) with pre-pressure container (29), <b>characterized in that</b> when triggering the pressure equalization between the pre-pressure container (29) and the cuff (25) by the comparator function according to embodiment 6, the delay function is activated and upon reaching the set delay time triggers a signal that the actuators to complete the pressure equalization between the form-pressure vessel (29) and the cuff (25) and activates the integrator function according to embodiment 7 such that when activated the output signal or the output value (13) of the integrator function according to embodiment 7 corresponds to the constant starting value according to embodiment 7.</li><li>According to Embodiment 9, the comparator function is a monostable threshold signal (2) of the electronic circuit according to Embodiment 1 <b>characterized in that</b> in the case of parity or the crossing of the sensor signal or sensor value (1) according to embodiment 2 with the monostable threshold signal or the monostable threshold (2), a signal is triggered, the actuator to terminate the increase (15) of the cuff ( 4) and activates the integrator function according to embodiment 7 such that when activated the output signal or the output value (13) of the integrator function according to embodiment 7 corresponds to the constant starting value according to embodiment 7.</li><li>According to embodiment 10, the comparator function is a monostable threshold signal or a monostable threshold value (6) of the electronic circuit according to embodiment 1 <b>characterized in that</b> in the case of the parity or the crossing of the output signal or of the output value (13) of the integrator function according to embodiment 7 with the monostable threshold signal or threshold value (6), a signal is triggered which activates the actuators for lowering (16) the cuff pressure (4 ) and / or activates the comparator function according to embodiment 5).</li><li>According to embodiment 11, the monostable offset signal or the monostable offset value according to embodiment 4 <b>characterized in that</b> it can be varied by parameter variation from the outside.</li><li>According to embodiment 12, the bistable threshold signal or the bistable threshold value (3) according to embodiment 5 <b>characterized in that</b> it can be varied by parameter variation from the outside.</li><li>According to embodiment 13, the monostable reference signal or the monostable reference value (5) according to embodiment 7 <b>characterized in that</b> it can be varied by parameter variation from the outside.</li><li>According to embodiment 14, the monostable threshold signal or the monostable threshold value (2) according to embodiment 9 <b>characterized in that</b> it can be varied by parameter variation from the outside.</li><li>According to Embodiment 15, the system for controlling the micturition of the electronic circuit according to Embodiment 1 <b>characterized in that</b> to activate the micturition, an external signal causes the actuators to lower the urethral closure pressure and deactivated the electronic circuit according to embodiment 1 except for the comparator function according to embodiment 5 and to deactivate the micturition an external signal the actuator to increase (15) of the cuff pressure (4th ) causes until in the case of parity or the crossing of the sensor signal (1) according to embodiment 2 with the bistable threshold signal or Threshold (3) according to embodiment 5, a signal is triggered, which activates the electronic circuit according to embodiment 1.</li></ul>

0055In this invention, a novel fine-sensory implant is presented, which combines the most important aspects of technological problems of in-vivo medical technology in itself: a reliable fine sensors, intelligent, flexible control electronics with low power consumption, a miniaturized and powerful actuators and a mature energy and data transfer. Using the example of this implant, an artificial, adaptive, fine-sensory sphincter, the current technical state of implant technology should be discussed against the background of the developmental history and the methodical criteria for selection control and alternative design including intensive tests for the determination of individual components while considering comparable implants.

0056The numbers in square brackets refer to references in the bibliography at the end of this description. The reference numbers refer to the<figref idref="f0013">FIGS. 12a to 12c</figref>.

0057An up-to-date system of an artificial bladder neck sphincter, exemplified by the AMS 800, uses a hand pump in the scrotum or large labia to inflate the urinary flow cuff around the urethra [6]. The problem with this system is the setting of Urethraverschlussdruckes. Too little pressure will result in unwanted leakage of urine under dynamic stress, which may be caused by laughter, coughing, sneezing or heavy lifting. Too much pressure on the urethra over a long period of time can easily lead to black tissue, a necrosis. In order to avoid this danger, so far in practice a slight stress incontinence with all its negative social consequences has been accepted.

0058The artificial fine-sensory sphincter implant developed according to the invention replaces the hand pump with an active hydraulic system equipped with a fine sensor system and intelligent control. With this system, the active pressure transmission can be supported or replaced. The sensors primarily monitor the difference between internal bladder pressure and cuff pressure. Under dynamic load, the actuator is used to increase the cuff pressure, so continence is guaranteed even at these elevated pressure ratios. This may affect the normal circulation of the urethral tissue in the short term. The implant can distinguish between one-off and ongoing dynamic loading.

control

0059The decisive factor for the function of the artificial fine-sensory sphincter implant is urethral closure pressure (31). If urethral closure pressure (31) becomes negative, urine leakage occurs.

0060The signal equivalent to the Urethraverschlussdruck (31) is determined from the two absolute pressure signals of the cuff (25) and the bladder (<figref idref="f0013">Fig. 12a</figref>). If there is a sudden dynamic load on the inside of the abdomen, this signal quickly approaches zero. In order to ensure a rapid reaction of the implant in this situation, the following measures are taken:

0061The decrease in Urethraverschlussdruckes (31) is bounded below by a switching threshold, which is above the incontinence range and can be varied during programming.

0062The course of the Urethraverschlussdrucksignals (31) is differentiated and added the positive portion of the lower threshold (12). The faster the urethral closure pressure (31) drops, the sooner the actorics of the implant will be activated due to this measure (t₁ (<figref idref="f0013">Fig. 12b</figref>).

0063This time-critical range is realized by means of analogous electronic components to allow a maximum reaction rate. The activation of the actuator is performed by a comparator, which compares the signal Urethraverschlussdruckes (31) with the lower threshold (12).

0064The use of a pre-pressure container allows a lightning-like reaction of the actuators at low supply voltage. After completion of pressure equalization (t₂) is the form (17) to a variable maximum value p_Max increased (within t₂ to t₃).

0065The lowering of the increased cuff pressure under the normal pressure threshold (3) equipped with a hysteresis is microprocessor-controlled after the end of the dynamic load. In order to obtain a measure of the dynamic load, the difference between an offset value (5), which can also be varied during programming, and the lower switching threshold (12) is integrated. With continuous dynamic load, the integration result (13) is thus pressed downward in a zigzag manner. Without dynamic load, the integration result (13) rises to a threshold value (6), at which the lowering of the cuff pressure is triggered (t₄) (<figref idref="f0013">Fig. 12c</figref>).

0066The normal pressure threshold prevents excessive cuff pressure during normal operation. This function, like the activation of the actuators, is also realized with analogue electronic components.

0067The analog circuit includes 4 variable parameters that are influenced by the D / A converter, namely: the rate of differentiation of the urethane closure pressure signal, the additive offset component of the lower threshold, and the mean and hysteresis of the normal pressure threshold. The permanently activated electronics are thus limited to a minimum of 6 operational amplifiers and a quad digital potentiometer of the analog circuit as well as to the signal conditioning and the RF receiver module. The total power consumption of the electronics amounts to less than 0.1 mW with the microprocessor in power-down mode.

Programming Software

0068The programming the artificial fine-sensory sphincter implant according to the invention is carried out by means of an external programming station. Via bi-directional transcutaneous data transfer, the urethral closure pressure and the absolute pressure in the pre-pressurized container are transferred to the programming station. The in-vivo pressure measurement paired with a simultaneous external urodynamic examination allows a far-reaching automation of implant programming. The patient performs defined physical movements, such as getting up from a sitting position or coughing. From the collected measurement data together with empirical values ​​from clinical tests, the software can evaluate an optimal setting of the implant. Subsequent required adjustments to the programming, for example, to changed living conditions of the patient or to changed behavior of the implanted electronics are also possible manually.

sensors

0069Proper functioning of the artificial sphincter implant requires the use of three pressure sensors, which must measure pressure at different locations and conditions:<ul id="ul0005" list-style="none" compact="compact"><li>The pre-pressurized container offers the use of a surface sensor, which can be integrated into the rigid base plate of the pre-pressurized container. This capacitive pressure sensor consists of a polysilicon membrane and a silicon substrate [1]. Between the polysilicon membrane and the silicon substrate, a vacuum is produced during production, so that an absolute pressure sensor is formed. For signal amplification, with the small diameter of 100-120 μm of a sensor element, a sensor array can be set up in parallel [2].</li></ul>

0070When using an absolute pressure sensor in the admission pressure vessel, the absolute pressure in the cuff can also be measured by means of a differential pressure sensor, which measures the difference between the cuff pressure and the admission pressure. By means of a suitable electronic circuit, the absolute pressure signal of the cuff pressure can be filtered out from the absolute pressure signal of the admission pressure vessel and the differential pressure signal between the cuff and the admission pressure vessel. This allows the use of a cost-effective and reliable piezoresistive differential pressure sensor, which is connected via hydraulic connections both to the pre-pressure tank and to the cuff.

0071To measure the internal pressure of the bladder, an absolute pressure sensor, similar to a cerebral pressure probe, is embedded in the tissue close to the bladder in order to avoid puncturing or opening the bladder [5]. The measured pressure may not be exactly the same as the internal bladder pressure, but it is equivalent.

electronics

0072The physical dimensions and the power consumption of the electronic components are not the critical parameters in the artificial sphincter implant, since both are negligible compared to the properties of the actuators. Nevertheless, a minimization is sought, although more emphasis can be placed on reliability and redundant systems.

0073The intended for the artificial fine-sensory sphincter implant control electronics is similar in terms of the requirements of a modern pacemaker. As in a pacemaker, sensor signals are evaluated by a microprocessor and converted into actions of the implant. In order to minimize the power consumption of the electronics, the microprocessor is operated in normal operation in power-down mode. The comparator, which activates the actuators under dynamic load, simultaneously activates the microprocessor.

0074The use of a programmable via transcutaneous data transmission microprocessor has the distinct advantage that can be flexibly responded to changes, for example, the life habits of the patient or in the behavior of the electronic components. The use of analog semiconductor components, for example as an arithmetic circuit for determining the cuff absolute pressure, is thereby less critical.

0075With a power consumption of less than 1 μA per op amp, the analog components can be easily permanently activated. The only temporarily active microprocessor can be operated with relatively high clock frequencies, since the associated relatively high power consumption can be easily compensated by a significantly improved performance of the implant.

0076While a cardiac pacemaker, a capacitor charged with up to 1kV must be switched (usually by IGBTs), which discharges via the human tissue between the electrodes with several ten amperes within a few milliseconds, the artifical fine sensory sphincter implant at a supply voltage of 4.2 V maximum continuous load currents of about 100 mA per switch connected. For this purpose, MOSFETs are available that can be operated directly by the microprocessor. To ensure reliability, several MOSFETs are connected in parallel per switching unit in order to handle the switching task without any problems if individual components fail. These can be integrated in a multi-chip module (MCM).

0077Signal Conditioning, Analog Circuit, A / D Conversion, Internal Memory, and Multi-I / O Module Microprocessor can be combined in a Mixed-Signal ASIC, an Application Specific Integrated Circuit [4]. This provides an extremely low power consumption, because unlike the use of a standard microprocessor, no unused features fallow but still consume power. This advantage is offset by a high development effort, which leads to the desired result via design, simulation and production. For this reason, the prototype of the implant is realized with a commercially available microcontroller. Developing an ASIC would be a disproportionate amount of time and money for a prototype.

0078Energy source is usually a lithium-ion battery, which is charged via a subcutaneously implanted induction coil. The charging controller of the lithium-ion battery pack is a commercial IC, which is used for example in mobile phones. It monitors the current flow between the energy transfer module and the battery, which it can influence with a MOSFET. Termination, abort and errors are reported to the microprocessor.

actuators

0079The miniaturization of implantable actuators requires components that meet the high demands of today's medical technology such as biocompatibility, longevity and reliability. In implantation medicine, silicones and polyurethanes, which are characterized by their biocompatibility, are among the most commonly used materials. In both mechanical and thermal stress tests it turned out that silicones and polyurethanes have quite equivalent properties. With more than 5 million load cycles, the durability for use in humans has been simulated and operated.

0080The Aktorik of the artificial fine-sensory sphincter implant consists of electrically active components, the valves and the pump, and passive, a pre-pressure chamber, an inflatable cuff and the hydraulic connections (<figref idref="f0014">FIG. 13</figref>). These components must be specially adapted for use in the artificial fine-sensory sphincter implant. Industrial pumps and valves are mostly designed for pressures of 10bar and more. Since maximum pressures of less than 500 mbar occur in the implant, an adapted dimensioning of these components makes sense.

0081The pre-pressure container consists of a rigid base plate, via which an elastic membrane is tensioned. Due to the flat design of the pre-pressure container can be integrated into the outer shell of the implant so that the elastic membrane can bulge outward when pressure is increased.

0082The crucial function of the artificial fine-sensory sphincter implant is the lightning-like increase in cuff pressure in the event of a sudden drop in urethral closure pressure. In order to minimize the time between activation of the actuators and achieving a safe cuff pressure, an increased pre-pressure is provided, which can be transmitted via the valve 3 to the cuff. As the electronics reach reaction times in the micro- to nanosecond range, the decisive gain in response time is to be expected in optimizing the system of admission pressure vessel, valve 3 and the hydraulic connection. If, for example, a flow of 0.2 ml is required to increase the cuff pressure from 70 mbar to 100 mbar and the pressure difference between the cuff and the pre-pressure vessel is equal to Δp before pressure equalization, the following proportionality results with an opening radius of the hose r (G1 ): <maths id="math0001"><math display="block"><mi mathvariant="normal">t</mi><mo mathvariant="normal">-</mo><mfrac><mn mathvariant="normal">1</mn><mrow><msup><mi mathvariant="normal">r</mi><mn mathvariant="normal">2</mn></msup><mo mathvariant="normal">⋅</mo><mi mathvariant="normal">Ap</mi></mrow></mfrac></math><img file="EP1513466B1_D0001.tif" /></maths>

0083Reaction times from activation of the actuators to the completion of the pressure equalization can be realized under 10 ms. For this purpose, a pressure difference of Δp = 400 mbar and an inner radius of the hydraulic connections of approximately r = 1.0 mm is necessary. With a further enlargement of the inner radius, even shorter reaction times can be realized.

0084Furthermore, the inertia of the valve 3 causes a further delay, which increases with increasing opening radius r.

0085The lowering of the cuff pressure via valve 2 into the reservoir. When dimensioning the valve 2 and the hydraulic connections between the cuff and the reservoir, care must be taken that the lowering of the cuff pressure does not occur too quickly. If this is the case, due to the inertia of the valve and the oncoming lower threshold, the increase of the cuff pressure can be triggered immediately. With a corresponding choice of the cross-sectional opening of the hydraulic connections, this danger can be avoided.

Energy and data transmission

0086In terms of energy and data transmission, most of the similarities with the artificial bladder [6] [7] [8] can be established. Unlike, for example, the artificial heart, the energy transfer in the artificial fine-sensory sphincter implant only serves to charge the implanted battery and the data transfer is mainly used to program the microprocessor. Furthermore, a further signal path is used for the micturition control, which is uncomplicated to use for the patient. From these framework conditions, the following configuration of the energy and data transmission was designed for use in the artificial fine-sensory sphincter implant:<ul id="ul0006" list-style="none" compact="compact"><li>The implanted battery is charged inductively by placing a charger on a subcutaneously implanted induction coil [3]. In order to enable fast bidirectional data transmission, an IR transmitter / receiver module is placed in the middle of the induction coil. This optical data transmission requires, like the inductive energy transfer, the application of the external counterpart directly to the skin.</li></ul>

0087This function can thus be integrated into the external charger.

0088Micturition is controlled by unidirectional RF data transmission. This allows the patient comfortable and uncomplicated operation of the implant. The micturition request as well as a signal to stop the micturition will be transmitted.

Results

0089It was achieved by a suitable design of the actuators and a corresponding design of the electronics, a lightning reaction of the hydraulics with the low supply voltage of 4.2 V and the complex behavior of the electronics with the low power consumption of less than 0.1 mW in the power-down Mode of the microprocessor. The behavior of the implant is designed so variable that it can meet an enormously wide range of requirements.

bibliography

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