阅读说明：本技术 通过电容测量进行金属植入物接触检测的方法和装置 (Method and device for detecting contact of metal implant by capacitance measurement ) 是由 B·彼得森 于 2018-08-22 设计创作，主要内容包括：本发明提供了一种用于通过电容测量进行金属植入物接触检测的方法和装置。电容测量通过导电布线/引线(例如主针)完成。当主针移动穿过皮肤和组织时,测量的电容增加,然后在主针与金属植入物接触时跳变,从而证明金属植入物存在和金属植入物的位置。电容测量的跳变是可检测的,因为电容的面积已经从主针移到了主针加上金属植入物表面积的表面积。该装置还可具有参考针,该参考针用于在围绕金属植入物的组织中进行参考针电容测量,以增加装置使用期间的准确度。提供用于支撑主针和参考针并且支撑或容纳装置电子器件的壳体。(The present invention provides a method and apparatus for metal implant contact detection by capacitive measurement. The capacitance measurement is done through conductive wiring/leads (e.g., main pins). The measured capacitance increases as the primary needle moves through the skin and tissue, and then jumps when the primary needle comes into contact with the metal implant, thereby evidencing the presence and location of the metal implant. The jump in capacitance measurement is detectable because the area of the capacitance has moved from the primary pin to the surface area of the primary pin plus the surface area of the metal implant. The device may also have a reference needle for reference needle capacitance measurements in tissue surrounding the metal implant to increase accuracy during use of the device. A housing is provided for supporting the primary and reference needles and supporting or housing the device electronics.)

1. An apparatus for metal implant contact detection by capacitive measurement, the apparatus comprising:

a housing defining an interior of the housing,

a primary needle supported by the housing;

a battery positioned inside the housing;

device electronics powered by the battery and in communication with the primary needle such that a capacitance measurement can be made when the primary needle is moving toward or away from the metal implant and a sudden increase in capacitance measurement is detected when the primary needle contacts the metal implant contacts; and the number of the first and second groups,

an output device in communication with the electronics for outputting the capacitance measurement.

2. The apparatus of claim 1, wherein the sudden increase in the capacitance measurement occurs in less than one microsecond and produces a capacitance of up to two picofarads.

3. The apparatus of claim 1, wherein an increased capacitance measurement depends on a size of the metal implant, such that the larger the metal implant, the larger the abrupt increase in the capacitance measurement.

4. The apparatus of claim 1, further comprising a reference needle for making a reference capacitance measurement of tissue surrounding the implant to improve accuracy of forward detection of the metal implant by comparing the capacitance measurement to the reference capacitance measurement as compared to a capacitance measurement made by the primary needle.

5. The device of claim 1, wherein the housing includes first and second opposing end walls, a bottom wall and opposing cover walls, and first and second opposing transverse walls defining the housing interior.

6. The apparatus of claim 5, wherein the cap wall defines a cap opening to the housing interior, and the cap has an annular recess wall defining an annular gasket recess, and the cap wall opening is centrally located with respect to the annular recess wall, and the protective cap has a gasket engagement surface, and a gasket is fitted in the annular gasket recess such that the gasket abuts the gasket engagement surface of the protective cap, and abuts the annular recess wall such that the gasket is secured to the cap wall.

7. The device of claim 6, further comprising a stabilizer member defining a stabilizer opening and the protective cover defines a cover interior and the stabilizer member fits in the cover wall opening and the primary needle extends through the stabilizer member such that the primary needle is stabilized by the stabilizer member while the primary needle is slidable through the stabilizer member, and wherein the bottom wall defines a bottom wall opening and the bottom wall opening is aligned with the cover wall opening such that the primary needle is extendable through the bottom wall opening.

8. The device of claim 7, wherein the cover wall defines a second cover wall opening and a reference needle stabilizer component fits in the second cover wall opening and the bottom wall defines a bottom wall reference needle opening and a reference needle protective cover is mounted on the cover wall to protect the reference needle and the second cover wall opening is aligned with the bottom wall reference needle opening and the reference needle stabilizer component.

9. The device of claim 1, wherein the device electronics include a charge time measurement unit and a peripheral interface controller for making a capacitance measurement while the primary needle is inserted into skin and tissue and while the primary needle is in contact with the metal implant.

10. The apparatus of claim 9, further comprising capacitance measurement software, wherein the apparatus electronics further comprise control circuitry that provides control of the capacitance measurement apparatus, and wherein the control circuitry comprises a current source and a charge time measurement unit, an analog-to-digital converter in communication with a multiplexer wired to a circuit capacitor, the circuit capacitor wired to a switched capacitor, such capacitance measurements made when the primary needle is moved toward the metal implant acting as a parallel capacitor, and the capacitance measurement software collects capacitance measurements and generates capacitance measurement output data indicating when the primary needle is closer to, moving away from, and contacting the implant.

11. The apparatus of claim 10, wherein the apparatus electronics takes a reference capacitance measurement when the reference needle is inserted into the skin and tissue, and wherein the capacitance measurements of the primary and reference needles are compared by the apparatus electronics to determine whether the primary needle is in contact with the metal implant, such that if the capacitance measurement of the primary needle matches the capacitance measurement of the reference needle, contact with the metal implant has occurred.

12. The device of claim 11, further comprising metal contacts, wherein one metal contact is routed to the primary pin and the device electronics for capacitance measurement and another metal contact is routed to the reference pin and the device electronics for reference pin capacitance measurement.

13. A method for metal implant contact detection by capacitive measurement, the method comprising:

a housing is provided that defines an interior of the housing,

providing a primary needle and supporting the primary needle with the housing;

providing a battery positioned inside the housing;

providing device electronics and a battery for powering the device electronics, and providing a primary needle in communication with the device electronics, and making a capacitance measurement as the primary needle moves toward or away from the metal implant, and detecting a sudden increase in capacitance measurement as the primary needle contacts the metal implant contacts; and the number of the first and second groups,

providing an output device in communication with the apparatus electronics, and outputting the capacitance measurement to the output device.

14. The method of claim 13, wherein the sudden increase in the capacitance measurement occurs in less than one microsecond and produces a capacitance of up to two picofarads.

15. The method of claim 13, wherein the increased capacitance measurement is dependent on a size of the metal implant such that the larger the metal implant, the larger the sudden increase in the capacitance measurement.

16. The method of claim 13, further comprising a reference needle for making a reference capacitance measurement of tissue surrounding the implant and comparing the reference capacitance measurement to a capacitance measurement made by the primary needle to improve the accuracy of forward detection of the metal implant by comparing the capacitance measurement to the reference capacitance measurement.

17. The method of claim 13, further comprising providing a housing, and providing the housing with a cover wall defining a cover wall opening, and providing the housing with an opposing bottom wall defining a bottom wall opening, and fitting a stabilizer component in the cover wall opening and extending the primary needle through the stabilizer component such that the primary needle is movable through body tissue and contacts the metal implant.

18. The method of claim 17, further comprising providing the device electronics with a charge time measurement unit and a peripheral interface controller for making a capacitance measurement while inserting the primary needle into skin and tissue and while the primary needle is in contact with the metal implant.

19. The method of claim 18, further comprising providing capacitance measurement software; and providing control circuitry for the device electronics to provide control of the capacitance measuring device; and providing the control circuit with a current source, a CTMU module, and an analog-to-digital converter in communication with a multiplexer and routing the multiplexer to a circuit capacitor; providing a switched capacitor and wiring the circuit capacitor to the switched capacitor, and wherein the capacitance measurement software communicates with the control circuit and collects capacitance measurements with the capacitance measurement software and generates capacitance measurement output data as the primary needle moves closer to, away from, and contacts the implant, and wherein the capacitance measurement output data is displayable on an output device.

20. The method of claim 19, further comprising providing metal contacts and connecting one metal contact to the primary pin and the device electronics to make a capacitance measurement; and connecting another metal contact to the reference needle and the device electronics to make a reference capacitance measurement and compare them to determine the presence of the metal implant.

Background

New technologies have been developed that involve temporary electrical interfacing with metal implants. One such technique involved requires the provision of an electrical current through the implant to eliminate biofilms on the metal surface that would otherwise prove difficult to break down. The challenge is that the implant will have been placed into the patient, for example in the leg or knee, and the body will have healed. In this case, the implant cannot be easily reached.

This means that in order to contact the implant, a lead or wire must be inserted through the skin and one or more leads/wires will need to make electrical contact with the metal implant. One challenge with this technique is that the implant cannot have anything attached to it, as anything attached to the implant may or will change the function of the implant. Another challenge with temporary contact is that the main needle must be brought into physical contact with the implant, and while this can be done by feel or X-ray guidance to ensure that the leads/wires are in contact with the metal implant, there is not enough existing solution or method to provide direct feedback that the wires/leads are actually in contact with the metal implant.

Accordingly, there is a need for a method and device that allows for the elimination of biofilm from the surface of a metal implant and overcomes the above-mentioned challenges. The device should be easy to use and provide a means of detecting metal implants, so that, for example, biofilms can be treated in a suitable manner.

Disclosure of Invention

A capacitance measurement device and method for metal implant contact detection by capacitance measurement are provided. Capacitive measurements are used to detect when a conductive lead, wire or primary needle made of metal is in contact with a metal implant. It is noted that throughout the specification, the terms wire, lead, and master pin are used interchangeably.

When the primary needle of a human body (e.g., a patient) is in contact with the implant as it moves through the body, the measured capacitance suddenly jumps or increases, and this sudden jump in measured capacitance evidences the presence or appearance of contact with the metal implant. When the main needle moves to the implant, the capacitance increases due to the capacitance of the body, and when the main needle or lead is in direct contact with the metal implant, the measured capacitance will jump a detectable amount because the area of the capacitance has become from the main needle to the main needle plus the metal surface area of the implant. By specifically looking for this sudden jump in capacitance, it is possible to detect when the main needle is in direct contact with the implant.

Additionally, in another embodiment, a reference needle is provided and used with the body as a method of measuring capacitance in the body. By comparing the capacitance measurement of the reference needle with the capacitance measurement of the primary needle that needs to be in contact with the metal implant, a more accurate detection can be achieved, since most of the body's capacitance will be blocked.

Drawings

FIG. 1 is a front cross-sectional view of a capacitance measuring device having a primary pin.

FIG. 1A is a cross-sectional view of the skin and tissue of a patient's body.

FIG. 2 is a top view of a housing assembly that is part of a capacitance measuring device.

Fig. 3 is a bottom view of the housing assembly.

Fig. 4 is a rear view of the housing assembly.

Fig. 5 is a front view of the housing assembly.

Fig. 6 is a left side view of the housing assembly.

Fig. 7 is a right side view of the housing assembly.

Fig. 8 is a perspective view of an implant.

Fig. 9 is a perspective view of the main pin and the contacts.

FIG. 10 is a schematic diagram of a circuit that is part of and provides control for a capacitance measuring device.

FIG. 11 is a front cross-sectional view of a capacitance measuring device additionally including a reference pin.

Fig. 12 is a schematic diagram showing circuitry operatively associated with the primary and reference pins.

Detailed Description

Fig. 1 shows a cross-sectional view of a capacitance measuring device 10. As shown in fig. 1-7, capacitance measuring device 10 includes a housing 12. The housing 12 includes a bottom wall 14 and an opposing cover wall 24 facing the bottom wall 14. As shown in fig. 1, 2-3, and 6-7, the housing 12 also includes opposing first and second end walls 16, 18. As shown in fig. 1, 4 and 5, the housing 12 further includes opposing first and second transverse walls 20, 22. The opposing first 16 and second 18 end walls extend from the bottom wall 14 to the lid wall 24, and the opposing first 20 and second 22 transverse walls extend from the bottom wall 14 to the lid wall 24. Thus, the opposing first and second transverse walls 20, 22 intersect the opposing first and second end walls 16, 18 and the cover wall 24, and the opposing first and second transverse walls 20, 22 intersect the opposing first and second end walls 16, 18 and the bottom wall 14.

The second transverse wall 22 is secured to the opposing first and second end walls 16, 18, the lid wall 24, and the bottom wall 14 by an adhesive 27 in one embodiment, or in another embodiment, is either releasably secured to the opposing first and second end walls 16, 18, the lid wall 24, and the bottom wall 14. In another embodiment, the second transverse wall 22 is secured to the opposing first and second end walls 16, 18, the cover wall 24 and the bottom wall 14 by fasteners 29, such as screws, as shown in FIG. 5. In another embodiment, the first transverse wall 20, the opposing first 16 and second 18 end walls, the lid wall 24 and the bottom wall are made or formed as a unitary body 21, as indicated by the dashed lines in fig. 1. The housing 12 may be implemented to have other shapes. The housing 12 also defines a housing interior 15, the housing interior 15 being defined by opposing bottom and cover walls 14, 24, first and second end walls 16, 18, and first and second transverse walls 20, 22. Removal of the second transverse wall 22 allows access to the housing interior 15, as shown in fig. 1.

As shown in fig. 1 and 3, the capacitance measuring device 10 also has a primary pin 28, the primary pin 28 having a head 37 and an opposing primary pin tip 38, and the bottom wall 14 defining a bottom wall opening 26, the bottom wall opening 26 being sized such that the primary pin 28 is movable through the bottom wall opening 26. The main needle 28 is made of metal. As shown in fig. 3, the cover wall 24 has a cover peripheral wall 25, the cover peripheral wall 25 defining a cover wall opening 30, and the cover wall 24 has opposing inner and outer cover wall surfaces 34, 35, and the outer cover wall surface 35 has an annular recess wall 31 defining an annular gasket recess 32. The lid opening 30 is centrally located with respect to the annular recess wall 31. That is, the annular recess wall 31 surrounds or encircles the cover wall opening 30 as shown. As shown in fig. 1, capacitance measuring device 10 includes a gasket 36 that can fit in annular gasket recess 32, and in one embodiment, gasket 36 is an O-ring gasket 36 a. In other embodiments, the annular recess wall 31 may have a different shape and the annular gasket recess 32 may have a different shape as long as the gasket can be fitted in the gasket recess, and all such embodiments are intended to be within the scope and spirit of the appended claims. Additionally and as shown in fig. 1, the cover wall opening 30 and the bottom wall opening 26 are aligned relative to one another, such as in the view shown in fig. 1, the cover wall opening 30 is vertically aligned with the bottom wall opening 26.

The capacitance measuring device 10 also includes a protective cover 40 made of plastic 41, and in one embodiment, the plastic 41 is rigid and may be transparent, tinted, or otherwise colored. In one embodiment, the protective cover 40 has a hemispherical shape 44 and defines a protective cover interior 46. The protective cover 40 also has a cover end wall 48, which may be flat, and opposing inner and outer cover surfaces 50 and 52. The protective cover 40 has a recessed cover portion 53 extending from the cover end wall 48, and the recessed cover portion 53 has a gasket engagement surface 54. The gasket 36 is fitted between the recessed cover portion 53 and the annular recessed wall 31 such that the protective cover 40 is secured to the cover wall 24 of the housing 12, i.e., the protective cover 40 and the cover wall 24 are interlocked with each other by the gasket 36. In another embodiment, the protective cover 40 may be secured to the cover wall 24 using an adhesive 27, and in such embodiments, the recessed cover portion 53 and the annular recessed wall 31 would not be present. The primary needle 28 has a primary needle tip 38 and may have a primary needle portion 37, with a portion of the primary needle 28 and the primary needle portion 37 being located in the cap interior 46.

The capacitance measuring device 10 also includes a stabilizer member 60 for stabilizing the primary pin 28, and in one embodiment, the stabilizer member 60 is made of silicone 62. The stabilizer member 60 may be made of other materials, such as elastomeric materials, plastics, and metals in other embodiments. The stabilizer member 60 has a convex stabilizer portion 64 with a convex surface 66 and has a base stabilizer portion 68 extending from the convex stabilizer portion 64. The base stabilizer portion 68 also has an abutment surface 70. The stabilizer member 60 defines a stabilizer opening 72, the stabilizer opening 72 being sized such that the primary needle 28 is movable through the stabilizer opening 72. In one embodiment, the stabilizer member 60 abuts the primary needle 28 to prevent the primary needle 28 from deviating from the route as the primary needle 28 moves into the body 198 of the patient 200, where fig. 1A shows the body 198 of the patient 200.

As shown in fig. 1, the stabilizer member 60 is fitted in the lid wall opening 30 such that the male stabilizer portion 62 abuts the peripheral lid wall 25 (fig. 2) formed in the lid wall 24. At the same time, the abutment surface 70 of the base stabilizer portion 68 abuts the inner lid wall surface 34 of the lid wall 24, as shown in fig. 1. The stabilizer member 60 is secured to the peripheral lid wall 25 by a friction or press fit between the peripheral lid wall 25 and the convex surface 64 of the convex stabilizer portion 62. In other embodiments, the adhesive 27 may also be used to secure the abutment surface 70 to the inner cap wall surface 34, such that the stabilizer member 60 is secured to the cap 24, or by using a combination of the above.

As shown in fig. 1, the capacitance measuring device 10 further includes a battery 92 positioned in the housing interior 15 of the housing 12, and the battery 92 may be implemented as a button battery 94 (indicated by a dotted line in fig. 1). The battery 92 is supported on the bottom wall 14. Batteries and button cells are well known to those of ordinary skill in the art and, therefore, will not be described in further detail herein.

The capacitance measuring device 10 performs a capacitance measurement, generally indicated by reference numeral 96, and the capacitance measurement 96 may be obtained by a capacitance line 97 connected or wired to the main needle 28. The capacitance measurement 96 is processed by the device electronics 118. Capacitance measurements 96 are taken over time to detect when the primary needle 28 touches or contacts a metal implant 100 (metal implant 100 shown in fig. 8). Housing 12 may be pushed to move primary needle 28 through skin 202 and tissue 204 while primary needle 28 is held in place by stabilizer member 60. This configuration allows the primary needle 28 to be used to make the capacitance measurement 96 as the primary needle 28 moves through the skin 202 of the patient 200, through the tissue 204 of the patient 200, and through the body 198 of the patient 108, and as the primary needle 28 contacts the metal implant 100. This significantly reduces the cost of the primary needle 28, as any conventional metal primary needle 28 can be used. In addition, the same main needle 28 is used to transmit electrical signals to the metal implant 100 for detecting the metal implant 100. In this embodiment, a puncture wound is made in the patient 200, but the procedure is also greatly simplified as it eliminates the need for an introducer (not shown).

For background purposes, it should be noted that humans have a measurable capacitance, for example, this commonly known phenomenon is used in conjunction with touch screen electronics. Here, when the primary needle is in contact with a person, the capacitance measurement 96 changes because the person has a measurable capacitance. The capacitance measurement 96 will shift when the primary needle 28 is in contact with the skin 202, and then the capacitance measurement 96 will continue to shift as the primary needle 28 penetrates the skin 202 and muscles and tissue 204 of the patient 200. When the primary needle 28 first makes contact with the skin 202, the capacitance immediately increases or jumps, for example, within one microsecond. As primary needle 28 moves through body 198, it either remains the same or shifts the increased capacitance depending on how deep primary needle 12 is moving.

It may sometimes be difficult to detect whether the primary needle 28 contacts the skin 202 and body tissue 204 or contacts the metal implant 100. Accordingly, the capacitance measuring device 10 further includes capacitance measuring software 110 for detecting the metal implant 100. Although capacitance measurement software 110 may acquire or detect capacitance measurement 96, it may also be able to block or ignore capacitance measurement 96 that is not indicative of a capacitance jump or increase. This is because the jump or increase in capacitance measurement 96 will be less when compared to the jump or increase in capacitance measurement 96 when the primary needle 28 contacts the metal implant 100. Thus, by blocking and ignoring the gradual ramp in the capacitance measurements 96 as the primary needle 28 is inserted deeper into the patient 200, the capacitance measurement software 110 allows for a more precise location of the metal implant 100 and thus avoids past problems — avoiding the positioning of the metal implant 100 and eliminating the need for extensive medical procedures for positioning the metal implant 100.

As shown in fig. 1, capacitance measuring device 10 includes a charge time measurement unit 114 (also referred to herein as CTMU module 114) built into a peripheral interface controller 116 (also referred to herein as PIC microcontroller 116) forming device electronics 118 (see fig. 4). The capacitance measurement software 110 is operatively associated with the PIC microcontroller 116. A battery 92 powers these components. The battery 92, CTMU module 114, and PIC microcontroller 116 are all located in the housing 12. As shown in fig. 1, the peripheral interface controller 116 is wired to a suitable output device 123, such as a screen display. Those of ordinary skill in the art know the details regarding how to accomplish such capacitance measurements. The CTMU module 114 and PIC microcontroller 116, and their use and operation, are known to those of ordinary skill in the art and therefore will not be described in further detail herein.

As shown in fig. 10, the capacitance measuring device 10 has a control circuit 150. Control circuit 150 includes a current source 152 and CTMU module 114 and an analog-to-digital converter 154 (sometimes referred to herein as a/D converter 154). The AD converter 154 communicates with a multiplexer 156 (sometimes referred to herein as a MUX 156), which multiplexer 156 is wired to a circuit capacitor 158 (sometimes referred to herein as a CCIR 158). The circuit capacitor 158 is routed to a switched capacitor 160 (sometimes indicated by CSW 160). Spaced from the CSW 160 is a parallel capacitor 161 (sometimes indicated by CF 161). In use, the control circuit 150 may detect when the primary needle 28 moves closer to, away from the metal implant 100, and detect when the primary needle 28 contacts the primary implant 100.

There are a number of ways to connect the device electronics 118 to the main pin 28, for example, as shown in fig. 1, it is an option to route the main pin 12 directly to the device electronics 118 through the capacitive lines 97.

In another embodiment, the capacitance measuring device 10 is and may be monitored wirelessly. In such embodiments, device electronics 118 runs the capacitance measurement software 110 previously mentioned. The device electronics 118 can output the capacitance measurement output data 120 to any suitable electronic device 127, such as a laptop computer, screen display, database, and other devices, including wirelessly outputting the capacitance measurement output data 120.

In another embodiment, the device electronics 118 and battery are located outside of the housing 12.

In another embodiment, the capacitance measuring device 10 can also include a metal contact 124 as shown in dashed lines in FIG. 1 and in solid lines in FIG. 9. The primary pin 28 makes electrical contact with the device electronics 118 by using metal contact wires 138. The metal contact 124 has a cylindrical portion 126 defining a spring opening 128 and has opposing first and second spring arms 130, 132 extending from the cylindrical portion 126. The first spring arm 130 extends to a first curved spring portion 134 and the second spring arm 132 extends to a second spring curved portion 136. The first curved portion 134 and the second curved portion 136 abut each other. As the primary needle 28 moves, the primary needle 28 pushes its first and second spring bends 134, 136 apart, passing through and passing through the spring opening 128 and through the first and second spring bends 134, 136. At the same time, the main needle 28 is clamped and stabilized by the first spring bent portion 134 and the second spring bent portion 136. The use of the metal contacts 124 described above allows the main needle 12 to be controllably moved and guided into the patient 200, and the metal contact wires 138 are used to transfer the capacitance measurements 96 to the device electronics 118. In addition, the opposing first and second spring arms 130, 132 are mounted on the bottom wall interior surface 140 or otherwise secured to the bottom wall interior surface 140 by, for example, an adhesive 27.

In use, primary needle 28 is positioned in housing interior 15 and a user, such as a physician (not shown), pushes housing 12 such that primary needle tip 38 penetrates skin 202 and moves through body tissue 204. At the same time, capacitance measurements 96 are made by the CTMU module 114 and processed by capacitance measurement software 110. If the measured capacitance does not increase, the user will know that there is no metal implant 100 in that particular area and can move the primary needle 28 to another location and reinsert the primary needle 28 into the patient 200. However, if the capacitance measurement 96 is measured while the primary needle 28 is inserted and by the capacitance measurement software 110 in contact with the metal implant 100, the user now knows exactly the location of the metal implant 100 and can use this information for almost any other purpose, such as exploratory surgery, scanning, and monitoring.

One challenge that has been overcome is that as the distance from the main needle tip 38 to the metal implant 100 decreases, the capacitance will begin to increase rapidly. The capacitance measuring device 10 can overcome this by setting a threshold, for example, in one embodiment setting the farad from one picofarad to one nanofarad, and in other embodiments, the farad threshold can be set from 1.3 picofarads to.08 nanofarads, and in other embodiments, the farad threshold can be two picofarads, because the metal implant 100 significantly increases the total surface area of the main needle 28 when the metal implant 100 and the main needle 28 are in contact with each other, and significantly increases the total capacitance to be measured. This sudden rise in capacitance measurement 96 may occur within one microsecond, and in other embodiments, within more or less than one microsecond.

In another embodiment, as shown in fig. 1 and 11, capacitive measurement device 10 further includes a reference needle 228, a reference needle shield 240, and a reference needle stabilizer assembly 260, the reference needle stabilizer assembly 260 defining a reference required stabilizer assembly opening 272. Thus, in this embodiment, there are both a primary needle 28 and a reference needle 228. In this embodiment, the bottom wall 14 further defines the reference needle bottom wall opening 226, and the cover wall 24 has a second cover peripheral wall 255, the second cover peripheral wall 255 defining the second cover wall opening 230, and the cover wall 24 has opposing inner and outer cover wall surfaces 34, 35, and the outer cover wall surface 35 has a second annular recess wall 231, the second annular recess wall 231 defining the annular gasket recess 232. The second cover wall opening 230 is centrally located with respect to the second annular recess wall 231. That is, the second annular recess wall 231 surrounds or encircles the second lid wall opening 230 as shown. As shown in fig. 1, the capacitance measuring device 10 includes a second gasket 236 that can fit in the second annular gasket recess 232, and in one embodiment, the second gasket 236 is an O-ring gasket 36 a. Additionally and as shown in fig. 11, the cover wall second cover wall opening 230 and the second bottom wall opening 226 are aligned relative to one another, e.g., in the view shown in fig. 11, the second cover wall opening 230 is vertically aligned with the second bottom wall opening 226. The remaining components of this embodiment

Reference needle 228 includes a reference tip segment 238 and a reference needle tip 238. A reference capacitor line 297 connects the reference pin 228 to the device electronics 118. The capacitance measurement software 110 can compare the capacitance measurement 96 obtained from the main pin 28 to the reference capacitance measurement 296 obtained from the reference pin 228. The reference needle 228 is moved into the body 198 and body tissue 204 proximate to the implant 100 or surrounding the implant 100.

Comparison of the capacitance measurement 96 with the reference capacitance measurement 296 will help eliminate the capacitance measurement of the body itself.

This increases the accuracy of determining whether the primary needle 28 is in contact with the metal implant 100 or not in contact with the metal implant 100.

For example, if capacitance measurement 96 suddenly increases rapidly and is higher relative to reference capacitance measurement 296, it will indicate that main needle 28 is in contact with metal implant 100. On the other hand, if capacitance measurement 96 is low relative to reference capacitance measurement 296, it will indicate that main needle 28 is in contact with metal implant 100.

Thus, the reference pin 228 improves the accuracy of the capacitance measuring device 10, improving the accuracy of the forward detection of the metal implant. It should be understood that the remaining surfaces and components in this embodiment are substantially the same as shown and described in connection with fig. 1, although not described in detail. Additionally, in this embodiment, another of the metal contacts 124 described above may be employed, but are not shown herein for clarity, to further contact and stabilize the reference pin 228.

As shown in fig. 12, the device electronics 118 also includes a first converter 298, and the first converter 298 is labeled U1, which converts the capacitance to a digital format. The first converter 298 may be implemented as an FDC2214 converter and is well known to those of ordinary skill in the art. First, second and third capacitors are also provided, labeled C1, C2, C3, to which a voltage of 3.3V is applied. In one embodiment, the first capacitor C1 is 1uF/6.3V, the second capacitor C2 is 0.1uF/25V, and the third capacitor C3 is 10000pF/25V, and they all extend to a first ground labeled 340 and along line 307 to a first voltage common collector indicated by VCC. An adder line 304 extends from the first converter 298.

A Serial Data (SDA) line 301 and a serial clock (SC L) line 302 extend from the first converter 298 labeled U1 additionally, a configurable interrupt output pin line 305 and a capacitor shutdown line 306 extend from the first converter 298.

As shown, the inverter and second ground strap extend along ground lines 308 and 317 to the first converter 298 and along lines 308 and 317 to the second ground 342.

The first IN0A and IN0B leads 309 and the second IN0A and IN0B leads 310 for measuring signal power extend from the first converter 298 and there is a first inductance labeled L1 of 18uH/120mA and a first capacitor labeled C1 has 33pF/50V which is used as the working capacitor measurement 96C 1 and L1 constitute a L C resonator for measuring capacitance changes.

The third IN1A, 1NAB lead 311 and the fourth IN1A, 1NAB lead 312 extend from the first converter 298 and there is a second inductance of 18uH/120mA, labeled L2, and a second capacitor, labeled C2, having 33pF/50V, which is used as a reference capacitance measurement 296.

There is also an oscillator 320 which may be 340MHz and which is well known and commercially available, for example, as shown, part number 625L 3C040m00000 as shown, oscillator 320 is used as a clock and has a voltage of 3.3V and a resistor labeled R1 with 10k ohms of 0.1% as shown, oscillator 320 is grounded through a third ground 344 and has a capacitor labeled C6 which is 10000pF/25V there is a second voltage common collector labeled VCC2, oscillator 320 has a second converter labeled U2 which converts the capacitance to digital form and a second converter U2 is in communication with the first converter U1 as shown.

The above-described configuration of the device electronics 118 allows for the capacitive measurement 96 to be made only through the primary pin 28 so that the metal implant 100 can be positioned, or the metal implant 100 can be used so that the capacitive measurement 96 can be made through the primary pin 28 and the reference pin 240.

U1 measures the frequency difference of the lc-loop using the precision clock signal from U2 to provide a change in capacitance. Using the clock and data lines and following the I2C protocol, the master MCU may make capacitance measurements. Channel 0(INA0, INB0) is used to measure contact with the implant and is inserted after the reference is placed in the body. The capacitance measurement of channel 1(INA1, INB1) is the capacitance measurement of the reference pin. After the working needle is placed in the body, the capacitance of channel 0 is completed, wherein the measurement of channel 1 is subtracted. Once the channel 0 is in contact with the metal implant, its capacitance will always be higher than the reference value. Furthermore, the capacitance change will look for a sudden change in capacitance measured in the range of 2pF-10nF over less than 100 mS.

It should be understood that all of the above quantities, such as those expressed in farads and capacitances, are for exemplary purposes and may be different in other embodiments, and it is intended that the quantities do not limit the scope of the present application.

In the past, most of the solutions and methods for detecting capacitance have required electrical connections to be made directly from the first and second leads connected to the implant 100, and then passing a small amount of power through the implant 100. If power flowing from the first lead is detected on the leads, it will be demonstrated that both leads are in contact with the metal implant 100. The challenge associated with this approach is the need for two leads or one lead with two separate electrodes. This adds complexity and cost. Another problem associated with this is that the user cannot tell which primary needle is not in direct contact with the implant, and this may lead to unwanted false negatives.

Another method used involves physical feedback by sensing resistance on the main needle 12 or wiring or leads. A problem with this approach is that the user does not know whether he or she is touching or touching metal or bone. X-rays may help guide the main needle, but may be difficult to determine because anything other than physical contact with the metal implant 100 is inoperable because electrical contact is needed. In addition, X-rays are typically two-dimensional images, and the loss of depth may mean that the main needle is actually contacting the bone rather than metal, and MRI cannot be performed due to the presence of ferrous metal on the implant.

Thus, the capacitance measuring device 10 of the present invention for the metal from which the capacitance measurement 96 is made overcomes significant problems associated with the methods and schemes described above.

Those skilled in the art will recognize that while the capacitance measuring device 10 for metal implant contact detection by capacitance measurement is not necessarily so limited, and that other examples, embodiments, uses, modifications, and departures from the embodiments, examples, uses, and modifications may be made without departing from the capacitance measuring device 10, all such embodiments are intended to be within the scope and spirit of the appended claims.