implant

Abstract

An implant comprising: a housing having a chamber; and a sensor unit; a first membrane covering the chamber on a first pressure side and a second membrane covering the chamber on a second pressure side; the chamber comprising a pressure transfer device in contact with the first membrane and the second membrane and the sensor unit arranged within the chamber between the first membrane and the second membrane, wherein a sensor control unit is arranged within the housing; wherein the sensor unit is configured to determine a pressure difference between a pressure of the first pressure side of the chamber and a pressure of the second pressure side of the chamber.

Description

Technical Field

[0001] Embodiments of the present invention relate to implants with differential pressure sensors and methods for manufacturing the same. Generally, the embodiments relate to the concept of in vivo differential pressure measurement. Background Technology

[0002] Pressure measurement within the human body has numerous applications. Examples include:

[0003] • Measurement of the pressure difference between the eye and body fluids

[0004] • Measurement of the pressure difference between the sphincter and the cuff reservoir pressure

[0005] • Measurement of the pressure difference between vascular reservoir pressure or cardiac pressure and body pressure

[0006] However, body pressure is not constant. If the pressure of the environment changes, then body pressure follows atmospheric pressure. The reasons are as follows:

[0007] • Pressure changes due to normal variations in atmospheric pressure at a given location

[0008] • Pressure changes due to altitude (e.g., climbing mountains)

[0009] Pressure changes inside the aircraft

[0010] These changes in atmospheric pressure are on the same order of magnitude as, or even greater than, differential pressure measurements.

[0011] The pressure sensor is shown with reference to it. Figures 1a to 1c Discuss existing technologies. Figure 1a These are implantable absolute pressure sensors, such as the HELGA pressure sensor. The pressure sensor is embedded in a liquid, which is housed within an airtight titanium housing. A thin titanium foil transfers pressure from the body to the liquid and the sensor.

[0012] However, this is only an absolute pressure sensor, so pressure changes caused by the environment can render the pressure value unusable. The background is that for some applications, such as the pressure differential between the implant and surrounding bodily fluids, is crucial. Therefore, if the bodily fluid pressure changes due to environmental conditions, the implant pressure also needs to change. An absolute pressure value is useless in this case.

[0013] Figure 1b A sensor similar to the HELG sensor is shown, in which the sensor is embedded in oil. This sensor suffers from the same drawbacks.

[0014] US 4,460,568 illustrates an implantable differential pressure sensor. Figure 1 of that patent is... Figure 1cAs shown, this pressure sensor uses two diaphragms. However, there is a fixed connection between the pressure sensor and the diaphragms. This can cause problems with high stress and drift in the pressure sensor. Figure 1d A differential pressure sensor is shown (see www.eastsensor.com / b1og / capacitance-differential-pressure-transmitter-working-principle / ). Summary of the Invention

[0015] The purpose of this invention is to provide a concept for an implant that can overcome the above-mentioned drawbacks.

[0016] This objective is addressed by the subject matter of the independent claims.

[0017] Embodiments of the present invention provide an implant comprising a housing and a sensor unit. It further includes a first membrane covering a chamber on a first pressure side and a second membrane covering the chamber on a second pressure side (e.g., for hermetically sealing the implant relative to its surrounding environment). The chamber includes a pressure transmission device that contacts the first and second membranes and the sensor unit disposed within the chamber between the first and second membranes. Furthermore, a sensor control unit is disposed within the housing. The sensor unit is configured to determine the pressure difference between the pressure on the first pressure side of the chamber and the pressure on the second pressure side of the chamber.

[0018] According to one embodiment, the sensor unit includes a membrane configured to measure the relative pressure between a pressure applied to a first side of the membrane from a first pressure side and a pressure applied to a second side of the membrane from a second pressure side. This embodiment advantageously allows for direct measurement of the relative pressure / pressure difference. According to another embodiment, the sensor control unit may include a first pressure sensor and a second pressure sensor, wherein the first pressure sensor is configured to measure the pressure on the first pressure side, and wherein the second pressure sensor is configured to measure the pressure on the second pressure side. Here, the pressure difference is determined starting from two absolute pressures, wherein the calculation of the pressure difference is performed by the sensor unit.

[0019] Embodiments of the present invention are based on the principle that an implant using a housing having a chamber within the housing, for example formed by a hole / opening, allows a sensor unit to be arranged within the chamber, such that a first pressure from a first pressure side and a second pressure from a second pressure side can be applied to the sensor. This allows the task of achieving hermetic sealing (through a membrane) to be locally separated from the task of low-stress encapsulation of the differential pressure measurement sensor unit (arranged within the pressure transmission device). For example, the chamber can extend from the first pressure side through the housing to the second pressure side. By using this arrangement, the pressure sensor can directly determine the pressure difference between the two sides.

[0020] According to an embodiment, the housing may include a diaphragm on which sensor units and / or sensor control units can be disposed. For example, the diaphragm may be disposed within a cavity. Here, according to an embodiment, the diaphragm may divide the cavity into a first part and a second part, wherein the sensor units may be attached to the diaphragm and disposed in the middle of the cavity.

[0021] According to another embodiment, a first foil can be used as a first membrane on the first pressure side, or a second foil can be used as a second membrane on the second pressure side. Here, the housing includes a first foil and a second foil. These foils can be arranged such that a sensor unit is disposed between them. According to an embodiment, the first foil covers the chamber on the first pressure side, while the second foil covers the chamber on the second pressure side. According to an embodiment, the first foil on the first pressure side and the second foil on the second pressure side hermetically seal the chamber (i.e., the sensor unit disposed within the chamber). According to another embodiment, the sensor control unit can also be hermetically sealed within the housing, for example, by using the first foil and the second foil. According to an embodiment, pressure on the first pressure side is applied to the pressure sensor via the first foil, while pressure on the second pressure side is applied to the pressure sensor via the second foil. Specifically, pressure on the first pressure side can be applied to a first side of the pressure sensor via the first foil, and pressure on the second pressure side can be applied to a second side of the pressure sensor via the second foil. The first foil and the second foil can be advantageously connected to the housing and hermetically seal the housing, while the sensor unit does not contact the first foil and the second foil, and is therefore unaffected during the manufacturing process. However, the foil can "relay" pressure on different sides. According to embodiments, the first and second foils can be formed from titanium foil, thin titanium foil, or PEEK foil (polyetheretherketone).

[0022] The chamber (e.g., a chamber enclosed by a first foil and a second foil) may be filled with air, oil, liquid, or casting compound as a pressure transmission medium. The oil or liquid, preferably non-conductive, biocompatible, and non-corrosive, or the casting compound, is incompressible, allowing pressure to be applied to the sensor from the foil in an optimal manner. According to embodiments, the chamber and / or the first and second foils may include guides for directing the liquid, oil, or casting during filling.

[0023] According to another embodiment, the housing may include a filter, a grid, a grid including a filter, a rigid grid, or a porous element. The element may, for example, surround a chamber on a first pressure side and a second pressure side, and / or surround a sensor unit from both pressure sides, and / or surround a first foil and a second foil around the housing. Such a rigid grid advantageously prevents the foil, chamber, or sensor unit from being encased in body material.

[0024] Another embodiment provides a method for producing the above-described implant. Here, the method includes the step of arranging a sensor unit in a chamber, for example, between two foils. According to an embodiment, the method may further include the step of perfusing the chamber and / or the area between the two foils. Here, perfusing may be performed before or after attaching the foils (first foil and second foil) to the housing. Attached Figure Description

[0025] Embodiments of the invention will then be discussed with reference to the accompanying drawings, in which:

[0026] Figures 1a to 1d The illustration schematically shows existing technical solutions for implants;

[0027] Figure 2 The basic implementation of the implant according to the first embodiment is illustrated schematically;

[0028] Figure 3a and Figure 3b An enhanced implementation of the implant according to an embodiment is schematically shown, in which two different sensor units are used;

[0029] Figure 4a Another illustrative implementation of an implant according to another embodiment is shown;

[0030] Figure 4b An implant according to another embodiment is shown. Figure 4a Indicative implant;

[0031] Figure 5 The illustration schematically depicts an embodiment according to another embodiment. Figure 3a Enhanced variations of implants; and

[0032] Figure 6a and Figure 6b The illustration schematically shows a method according to another embodiment. Figure 4a Enhanced variants of the implant. Detailed Implementation

[0033] Hereinafter, embodiments of the invention will be discussed with reference to the accompanying drawings, wherein the same reference numerals are provided for elements or structures having the same or similar functions, such that their descriptions are applicable and interchangeable.

[0034] Figure 2 An implant 10 including a housing 12 is shown, the housing including a chamber 12c. A sensor unit 14 may be arranged within this chamber. A sensor control unit 16 may be arranged somewhere within the housing 12.

[0035] The chamber 14c can be formed, for example, by a hole extending from a first side of the housing 12 to a second side of the housing 12. The two sides are marked 12s1 and 12s2. A first pressure P1 can be applied to the sensor 14 via the side marked 12s1, while a second pressure P2 can be applied to the sensor 14. Since these two pressure levels P1 and P2 are applied from the sides 12s1 and 12s2, the sides 12s1 and 12s2 are also referred to as the first pressure side and the second pressure side.

[0036] According to an embodiment, pressure sensor 14 can be a membrane to which two pressures P1 and P2 are applied from two pressure sides 12s1 and 12s2. Here, pressure P1 applies to a first side of the membrane, while pressure P2 applies to a second side. The membrane moves according to the pressure difference between P1 and P2, and this movement can be determined piezoelectrically or resistively (preferably) or capacitively. For example, a piezoresistive (differential pressure) pressure sensor uses a strain gauge coupled to the membrane to determine the membrane's offset, thereby determining the applied pressure. A piezoelectric membrane uses a material such as quartz, enabling direct measurement of the membrane's strain, thereby measuring the pressure. Alternatively, the membrane can form a first electrode, with a second electrode formed by a grid arranged parallel to the membrane. This arrangement forms a (differential pressure) sensor. According to an alternative variation, the sensor using 14 can be formed by two independent pressure sensors, each determining one of the two pressures P1 and P2, so that the pressure difference between P1 and P2 can be calculated, for example, by using a sensor control unit 16. Between the membranes 20s1 / 20s2 and the sensor unit 14, a pressure transmission medium / device, such as a fluid or oil, is arranged to transmit pressures P1 / P2 from the first pressure side 12s1 and the second pressure side 12s2 to the sensor 14, respectively. For this purpose, the sensor unit 14 can be embedded in the pressure transmission device.

[0037] According to an embodiment, chamber 12 may be covered by corresponding foils (films). For example, a first foil 20s1 may be applied to a first side 12s1 of chamber 12, wherein a second foil 20s2 may be applied to a second side 12s2. These two foils 20s1 and 20s2 cover chamber 12 from both sides 12s1 and 12s2, for example, to airtightly seal the chamber and the elements disposed within chamber 12c. Specifically, pressure sensor 14 may be disposed between the two foils 20s1 and 20s2. Here, the two foils 20s1 and 20s2 may be configured to “forward” pressures P1 and P2 to sensor 14.

[0038] Further optional features according to the embodiments will be discussed with reference to the accompanying drawings.

[0039] Before discussing other embodiments and benefits, and particularly for different applications, the areas of application will be discussed. Preferably, a pressure measuring device can be used to measure pressure within the human body:

[0040] The human body is a system with many different pressure zones (brain, eyes, inner ear, colon) and flows according to pressure differentials. Some of these pressure differentials are enormous (such as body pressure), while others are very small. The only available technique is to measure two absolute pressures and subtract them from each other. Because body pressure fluctuates with atmospheric pressure, these measured pressures also fluctuate with atmospheric pressure. This makes it very difficult to measure the tiny pressure differentials within the body.

[0041] • If a technology were available that could measure the true pressure difference between two locations within the body, it would provide a wealth of information about bodily functions.

[0042] Therefore, an absolute pressure sensor is not needed; instead, a differential pressure sensor is required, which can measure the pressure difference between two locations separated by a body diaphragm.

[0043] To measure differential pressure, the pressure sensor must contact the two pressure zones to be measured. Next, the pressure sensor must be electrically connected to the implant's system control unit. These electrical contacts must be hermetically sealed. However, pressure sensors are highly sensitive to stress. Hermetically sealing (e.g., a tight hermetically sealed connection to a titanium housing) can result in high stress effects.

[0044] Therefore, it is almost impossible to hermetically bond a pressure sensor chip with pressure contact with two pressure zones to an implant without generating large stress on the pressure sensor.

[0045] However, as mentioned above, improved design of the implant (whose housing includes a chamber) can solve this problem. The background is that a pressure sensor / differential pressure sensor can be arranged within the chamber so as to be hermetically sealed, for example, by using a foil configured to provide external pressure to the internal sensor unit. This foil can be applied in a stress-free manner. (Refer to...) Figure 3a and Figure 3b The discussion includes embodiments of this foil (here, a thin titanium foil). Figure 3a and Figure 3b These two embodiments are comparable to each other, except that the sensor units used are different.

[0046] Figure 3aAn implant 10 with a housing 12 is shown, the housing comprising two portions 12a and 12b (on a first and a second side relative to a chamber 12c). A differential pressure sensor 14 is disposed within the chamber 12c. In this embodiment, the pressure sensor 14 is attached to a diaphragm 15 capable of pressure separation (e.g., non-airtight). The diaphragm 15 extends along the longitudinal direction of the implant 10 / housing 12 to divide the chamber 12c into a first portion 12c1 and a second portion 12c2. The first chamber 12c1 is disposed on side 12s1, and the second chamber 12c2 is disposed on the second side 12s2. Regarding the diaphragm, it should be noted that this allows for the division of the chamber 12c into an upper and lower portion, wherein the diaphragm 15 can be implemented using a foil that is very thin against the body.

[0047] On the one hand, it is airtightly and tightly installed into the implant shell.

[0048] On the other hand, the plate stiffness, defined by the geometry and Young's modulus of the foil, should be very low so that the inherent stress of the foil caused by the change in the pressure to be measured does not significantly affect the measurement signal.

[0049] Alternatively, the diaphragm 15 may be rigid or have reduced flexibility.

[0050] Chamber 12c1 is covered by a thin foil, here a thin titanium foil 17s1, while chamber 12c2 is covered by a similar foil, such as the same foil 17s2. By using these two foils 17s1 and 17s2, chamber 12 is hermetically sealed relative to the surrounding environment.

[0051] In this embodiment, the housing 12 includes another hermetically sealed portion for the control system 14. Here, the control system 14 is arranged within a hermetically sealed titanium housing.

[0052] According to an embodiment, chamber 12, or particularly the first portion 12c1 and the second portion 12c2 of the chamber, may be filled with oil or a casting compound. This is indicated by reference numeral 13. The purpose of the oil or casting compound is to apply the pressure applied to the foils 17s1 and 17s2 to the membrane of the pressure sensor 14. It should be noted here that the pressure sensor 14 in the sensing chamber 12c is embedded in this oil. As an alternative to oil, a non-conductive, incompressible, harmless liquid, such as biocompatible oil 13, can be used. Regarding the liquid, it should be further noted that, according to a preferred embodiment, chamber 12c can be infused with an incompressible liquid that is preferably free of air bubbles. Air bubbles can affect the measurement because gases are compressible.

[0053] Here, the implant can be placed inside the body, allowing for the measurement of two different pressures in the body. For example, on the second pressure side 12s2, body pressure P2 can be measured, while on the first pressure side 12s1, reservoir pressure or cuff pressure P1 can be measured.

[0054] In summary, this embodiment enables measurement of the pressure difference between the upper region 12c1 and the lower region 12c2 of chamber 12c by using a differential pressure sensor 14 disposed within the pressure measurement chamber 12. Here, the pressure sensor 14 is mounted on a diaphragm 15 that separates the upper 12c1 and lower 12c2 of chamber 12c. According to another embodiment, the diaphragm 15 is rigid. It may be contained within an electrical conductor to conduct the pressure sensor readings to the system control unit 16 and to read the sensor 14. Existing methods for mounting pressure sensors can be applied to mount the pressure sensor 14 into chamber 12c under minimal stress.

[0055] Figure 3b An implant 10' is shown, which conforms to the structure of the housing 12, chamber 12c, control unit 16, and diaphragm 15. Furthermore, the implant 10' includes two foils 17s1 and 17s2 covering the chamber 12c. Within the chamber 12c, two pressure sensors 14s1 and 14s2 are arranged. These two pressure sensors 14s1 and 14s2 are arranged on two opposite sides of the diaphragm 15, such that pressure sensor 14s1 is configured to determine the pressure P1 at side 12s1, and pressure sensor 14s2 is configured to determine the pressure P2 at side 12s2. In other words, this means that two absolute pressure sensors 14s1 and 14s2 are installed, one in contact with the upper chamber and the other with the lower chamber. The pressure difference can be determined by calculating the difference between the two pressure values. Figure 3a Compared to traditional packaging, this type of packaging is simpler and easier because it eliminates the need for holes in the rigid, separated chamber.

[0056] Both embodiments of implants 10 and 10' are capable of performing the tasks of airtight sealing and differential pressure measurement. According to another embodiment, additional sensors (e.g., N sensors), which can be either differential or absolute sensors, can be placed within chamber 12c. For example, multiple of the N sensors can be fixed to diaphragm 15.

[0057] exist Figure 4a and Figure 4b In this context, another implant 10 will be discussed. Figure 4a An implant 10” including a housing 12” is shown. Within this housing, an enlarged chamber 12c” can be formed. (See diagram for reference.)

[0058] exist Figure 3a and Figure 3bIn the context discussed, the diaphragm 15” can extend through the chamber 12c” substantially parallel to the foils 17s1” and 17s2”. On the diaphragm 15”, a...

[0059] The pressure sensor 14 is equipped with control elements 16a” and 16t” (e.g., an ASIC and a transponder). These two entities 16a” and 16t” can be arranged on the same side or different sides relative to the pressure sensor 14.

[0060] All three elements 16a”, 14, and 16t” are arranged within chamber 12c”, which can be filled with liquid or oil. Here, the electronics 16a”, 16t”, and sensor 14 are embedded in oil 13. This arrangement allows for a reduction in the size of the differential pressure measuring unit 10”. Here, the sensor can have a thickness of 1 mm or less.

[0061] about Figure 4b The following discussion will cover how to secure the differential pressure sensor / implant 10” to the human body. Here, the implant 10” should be attached to a body diaphragm 22. This diaphragm 22 separates two pressure zones, P1 and P2. The housing 12” (here, a titanium housing) can be attached to the body diaphragm 22 using a biocompatible fixation material 23. Here, it may be helpful to combine the titanium sensor element 10” with a biocompatible material, whereby the titanium housing and the body diaphragm 22 can be secured by a surgeon.

[0062] Figure 5 An implant 10 including a housing 12 is shown. The chamber 12c is filled with oil. Two different infusion methods are presented here. According to a first alternative, infusion can be performed before the second foil 17s2 is hermetically installed onto the housing 12. Its advantage is that no infusion procedure or infusion port is required. However, handling the liquid during the sealing process parameters may be difficult. According to another alternative, infusion can be performed after the foils 17s1 and 17s2 have been installed to hermetically seal the housing 12. Here, infusion is performed on the chamber portions 12c1 and 12c2 using an infusion port (not shown).

[0063] Line injection. This port can be arranged as follows:

[0064] For example, four infusion ports are required for the inlet and outlet of the upper and lower chambers.

[0065] • Compared to foil, it may be easier to airtightly close these filling ports after filling.

[0066] Both chambers can have "guide structures" to enhance bubble-free filling. These structures can be tortuous to avoid air bubbles remaining at the chamber edges. The guide structures should not interfere with pressure measurement functionality.

[0067] As an alternative to oil, a very soft, cast, but incompressible (compared to air) compound can also be used instead of liquid oil. This casting compound can be filled into the chamber during the installation of the pressure sensor diaphragm, and before the second titanium foil is hermetically installed.

[0068] like Figure 5 As shown, bubbles 13a may form within chamber 12c during infusion. The effect of these bubbles 13a in sensor chamber 12c will be discussed below.

[0069] If there is an atmospheric pressure p in the sensor chamber (top chamber or bottom chamber) o The lower volume is V gas If air (or gas) bubbles are present, the measurement accuracy will be affected.

[0070] Calculation: Jet capacity of thin titanium foil: Cm

[0071]

[0072] For small deviations, the jet capacity can be analytically calculated from the plate theory based on the geometry, Young's modulus, and Poisson's ratio of the thin titanium foil.

[0073] The jet capacity of the bubble (assuming atmospheric pressure is po) can be estimated using the isothermal equation of state:

[0074]

[0075] The pressure change of dp alters the volume of the bubble:

[0076] dV gas =C gas dp

[0077] Based on this volume change, the thin titanium foil can also be moved:

[0078] dV m =dV gas

[0079] For the offset of thin titanium foil sheets, an inherent pressure dpi is required:

[0080]

[0081] The inherent pressure dpi will be the contribution of the bubble to the bubble measurement error.

[0082] According to an embodiment, chamber 12c can be filled with air instead of liquid. This has the advantage of eliminating the need for a filling process, thus simplifying the manufacturing process. However,

[0083] The titanium diaphragm will move during the measurement due to the compressibility of air. The inherent stress of the offset titanium foil will affect the measurement.

[0084] • If the absolute pressure changes (e.g., in a patient on an airplane), the jet capacity of the trapped bubble will change, and the correction factor for the pressure measurement will also change.

[0085] Regarding the control electronics 16, it should be noted that, according to the embodiment, a temperature sensor may be integrated into the implant 10 to compensate for temperature changes within the body, such as those caused by heat.

[0086] Regarding the materials, it should be noted that:

[0087] In principle, any material suitable for long-term implantation can be used. For example, PEEK can be used as a material for implants; however, thin PEEK foils are difficult to fabricate into an airtight seal. In practice, titanium would be the preferred solution for both the shell and the foil.

[0088] Regarding the foil, it should be noted that this function should be ensured by using titanium foil with a thickness between 20 and 50 μm and a lateral dimension (pressure measurement area) of 5 to 15 mm.

[0089] about Figure 6a and Figure 6b Additional features will be discussed.

[0090] Figure 6a It shows Figure 4b The implantation process involves attaching the implant 10 to the body diaphragm 22 using a biocompatible fixation material 23.

[0091] One possible scenario for measuring intracellular pressure or pressure differential is that the pressure sensor is encased in body material 26 after a certain period of time. This could raise two issues:

[0092] • The 26 layers of body material deposited on the pressure-sensitive side 12s1 and 12s2 generate mechanical stress on the diaphragm, thereby affecting the measurement results of the pressure sensor;

[0093] • This layer may be a pressure barrier, where a pressure drop may occur.

[0094] Figure 6b The solution to this problem is shown, which demonstrates the relationship with... Figure 6aThe same arrangement is shown, wherein the implant 10” is reinforced by a filter bag 28f. This filter bag 28f can be combined with a support 28 and serves to separate the pressure-sensitive titanium diaphragm 10” from the body 26. The filter bag 28f can be supported by a rigid grid 28 to avoid mechanical shock, force, or pressure on the measuring diaphragm. Thus, only very small molecules (water, oxygen, carbon dioxide, glucose, etc.) or molecules without cells or other potentially adaptable layers can pass through the filter 28f. Note that alternatives to the grid 28 including the filter 28f or filter bag 28f are conventional grids, rigid grids, or generally porous elements. The pores of the porous element, filter 28f, or grid can preferably be smaller than cells or other body materials that can aggregate and / or deposit onto the pressure-sensitive titanium diaphragm (e.g., less than 200 nm or less than 50 nm).

[0095] The filtering area 28f is large enough that, during the intended implantation time, the pressure sensor 16 will not be completely enclosed in a manner that results in a significant pressure drop between the body and the area above the titanium membrane.

[0096] Next, no material was able to exert stress on the titanium membrane 10” through this filtration area.

[0097] Note that the differential pressure sensor and / or implant 10, 10', 10" may include a fixation device for connection to a human diaphragm that separates two different pressure sides / regions within the body. Another application is in conjunction with a cuff reservoir.

[0098] Here, the aforementioned differential pressure measurement can be used for artificial implanted sphincter prostheses in the urethra (alternatively, it can also be used to replace the functions of other body sphincter muscles, such as the anal sphincter, upper esophageal sphincter, pyloric sphincter, ileocecal sphincter, etc.).

[0099] Implant settings:

[0100] • A hydraulically actuated implant that can close the urethra to put the patient into a state of restraint, and open the urethra to allow the patient to urinate.

[0101] The hydraulically actuated fluid is brine, which is moved by a mechanically or electrically driven pump.

[0102] • To close or open the urethra, a so-called cuff (i.e., an inflatable long balloon) is wrapped around the urethra in a circular shape, replacing the closing function of the previous human sphincter.

[0103] • A second inflatable reservoir (i.e., the so-called balloon reservoir) is located inside the patient's abdomen to store the fluid pumped out when the balloon is opened to urinate.

[0104] • To systematically control and prevent excessive pressure on urethral tissues, it is important to measure the urethral closure pressure compared to the surrounding body pressure.

[0105] In this way, the following pressures can be determined:

[0106] • Abdominal body pressure can be measured by sensing the pressure within the fluid lines of the airbag reservoir.

[0107] • Urethral closure pressure can be measured within the cuff fluid circuit.

[0108] Therefore, the differential pressure sensor between these two fluid lines within the implant can provide these sensor values.

[0109] The optional specifications for this application are:

[0110] • Airtightness between fluid lines and sensor electronics;

[0111] • Complete pressure differential measurement between urethral cuff pressure and abdominal pressure.

[0112] In this application, the implantable differential pressure sensor is embedded in an environment containing a saline solution rather than bodily fluids. There is no bodily fluid on either pressure side. Therefore, no additional measures are needed to protect the diaphragm. Figure 6b ).

[0113] In addition, this pressure sensor can also be used to measure the pressure difference between a saline solution reservoir and bodily fluids.

[0114] Although some aspects have been described in the context of the apparatus, it is clear that these aspects also represent a description of the corresponding method, where a block or device corresponds to a method step or feature of a method step. Similarly, aspects described in the context of method steps also represent a description of a corresponding block or item or feature of the corresponding apparatus. Some or all of the method steps may be performed by (or using) hardware devices, such as microprocessors, programmable computers, or electronic circuits. In some embodiments, some of one or more of the most important method steps may be performed by such devices.

[0115] Some embodiments of the invention include a data carrier having electronically readable control signals, which is capable of cooperating with a programmable computer system to perform one of the methods described herein.

[0116] Another embodiment includes a processing device, such as a computer or programmable logic device, configured or adapted to perform one of the methods described herein.

[0117] Another embodiment includes a computer having a computer program installed thereon for performing one of the methods described herein.

[0118] In some embodiments, a programmable logic device (e.g., a field-programmable gate array) may be used to perform some or all of the methods described herein. In some embodiments, the field-programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. Generally, these methods are preferably performed by any hardware device.

[0119] The above embodiments are merely illustrative of the principles of the invention. It should be understood that modifications and variations of the arrangements and details described herein will be apparent to those skilled in the art. Therefore, the intent is to be limited only by the scope of the pending patent claims, and not by the specific details presented in the description and explanation of the embodiments herein.

Claims

1. An implant, comprising: a housing having a chamber; a sensor unit; a first membrane covering the chamber on a first pressure side and a second membrane covering the chamber on a second pressure side; wherein the chamber comprises a pressure transfer means formed by an incompressible liquid or a casting compound, the pressure transfer means being in contact with the first membrane and the second membrane and the sensor unit arranged within the chamber between the first membrane and the second membrane; wherein a sensor control unit is arranged within the housing; wherein the sensor unit is configured to determine a pressure difference between a pressure of the first pressure side of the chamber and a pressure of the second pressure side of the chamber; wherein the chamber extends from the first pressure side through the housing to the second pressure side, and wherein the housing comprises a septum dividing the chamber into a first part and a second part; wherein the septum holds the sensor unit; wherein the first membrane comprises a first foil, and wherein the second membrane comprises a second foil, and wherein the chamber is covered by the first foil on the first pressure side and by the second foil on the second pressure side so as to hermetically seal the chamber; and wherein the implant comprises a fixation means connected to a body membrane separating two different pressure sides, wherein the sensor unit determines a pressure difference between the two different pressure sides.

2. The implant according to claim 1, wherein the sensor unit comprises a membrane configured to measure a relative pressure between a pressure applied from the first pressure side to a first side of the membrane of the sensor unit and a pressure applied from the second pressure side to a second side of the membrane.

3. The implant according to claim 1, wherein the sensor unit comprises a sensor device having a first pressure sensor and a second pressure sensor, wherein the first pressure sensor is configured to measure a pressure of the first pressure side, and wherein the second pressure sensor is configured to measure a pressure of the second pressure side.

4. The implant according to claim 1, wherein the housing comprises the septum, the sensor unit and / or the sensor control unit is attached on the septum; and / or wherein the septum extends through the chamber.

5. The implant according to claim 1, wherein the first foil on the first pressure side and the second foil on the second pressure side hermetically seal the chamber; and / or wherein the housing hermetically seals the sensor control unit.

6. The implant according to claim 1, wherein a pressure of the first pressure side is applied to the sensor unit via the first foil and the pressure transfer means, and wherein a pressure of the second pressure side is applied to the sensor unit via the second foil and the pressure transfer means; or wherein the pressure of the first pressure side is applied to a first side of the sensor unit via the first foil and the pressure transmission device, and wherein the pressure of the second pressure side is applied to a second side of the sensor unit via the second foil and the pressure transmission device.

7. Implant according to claim 1, wherein the first foil and / or the second foil comprises a titanium foil or a polyether ether ketone foil.

8. Implant according to claim 1, wherein the chamber or the first and second part of the chamber is filled with the incompressible liquid or casting compound forming the pressure transmission device; and / or wherein the chamber or the first and second part of the chamber is filled with the incompressible liquid or casting compound forming the pressure transmission device, and wherein the sensor control unit is embedded within the incompressible liquid or casting compound.

9. Implant according to claim 1, wherein the chamber or the first and second part of the chamber comprises a guide for guiding the incompressible liquid or casting compound.

10. Implant according to claim 1, wherein the housing comprises a filter, a grid or a porous element surrounding the chamber, the sensor unit or surrounding the foil or the first and second foil of the housing.

11. A cuff reservoir comprising an implant according to claim 1, wherein the implant is implemented as part of a cuff reservoir, wherein the sensor unit determines a pressure difference between two different pressures within the cuff reservoir or the cuff reservoir relative to the surrounding environment.

12. A method for producing the implant of claim 1, wherein the method comprises the steps of: arranging the sensor unit within the chamber and / or between the two foils.

13. The method of claim 12, wherein the method comprises the steps of: priming the area between the chamber and / or the two foils; and / or wherein the priming step is performed before or after attaching the two foils and / or the first and second foil to the housing.

Images