MEDICAL SYSTEM COMPRISING AN IMPLANTED INTERNAL UNIT, AN EXTERNAL UNIT, AND A METHOD OF INITIATING OPERATION OF EXTERNAL UNIT

Abstract

A method of initiating operation of an external unit for a medical system further comprising an internal unit implanted into a body of a patient; a transformer core arranged under the skin of the patient; and internal cabling connecting the internal unit and the transformer core, the internal cabling comprising an internal winding around the transformer core, wherein the external unit comprises external cabling including an external winding around the transformer core to allow supply of power from the external unit to the internal unit via the transformer core, the method comprising the steps of: evaluating, by the external unit, a signal indicative of a magnetic flux in the transformer core; when the signal indicates that the magnetic flux in the transformer core is below a predefined threshold flux, providing power to the internal unit by the external unit via the transformer core.

Claims

1. A method of initiating operation of an external unit for a medical system further comprising an internal unit implanted into a body of a patient; a transformer core arranged under the skin of the patient; and internal cabling connecting the internal unit and the transformer core, the internal cabling comprising an internal winding around the transformer core, wherein the external unit comprises external cabling including an external winding around the transformer core to allow supply of power from the external unit to the internal unit via the transformer core, the method comprising the steps of: evaluating, by the external unit, a signal indicative of a magnetic flux in the transformer core; when the signal indicates that the magnetic flux in the transformer core is below a predefined threshold flux, providing power to the internal unit by the external unit via the transformer core.

2. The method according to claim 1, wherein the step of evaluating is carried out automatically following activation of the external unit.

3. The method according to claim 1, wherein the external unit further comprises sensing circuitry coupled to the external cabling, and the method further comprises the steps of: activating the sensing circuitry; and providing, by the sensing circuitry, the signal indicative of the magnetic flux in the transformer core.

4. The method according to claim 1, further comprising the step of: providing a predefined indication when power is being provided by the external unit to the internal unit.

5. The method according to claim 1, wherein the signal indicative of the magnetic flux in the transformer core is selectively indicative of the magnetic flux within a predefined frequency range.

6. The method according to claim 5, wherein the predefined frequency range has a lower boundary frequency which higher than 5 kHz.

7. The method according to claim 1, comprising the steps of: activating sensing circuitry comprised in the external unit and configured to sense a property indicative of magnetic flux in the transformer core, and to provide a sensed signal indicative of a sensed value of the property; acquiring, from the sensing circuitry by processing circuitry comprised in the external unit, the signal indicative of the sensed value; comparing, by the processing circuitry, the sensed value with a stored value indicative of a threshold magnetic flux; and controlling, by the processing circuitry, power supply circuitry comprised in the external unit to provide power to the internal unit via the transformer core, when the comparison indicates that the magnetic flux in the transformer core is lower than the threshold magnetic flux.

8. An external unit for a medical system further comprising an internal unit implanted into a body of a patient; a transformer core arranged under the skin of the patient; and internal cabling connecting the internal unit and the transformer core, the internal cabling comprising an internal winding around the transformer core, wherein the external unit comprises: external cabling configured to allow formation of an external winding around the transformer core; sensing circuitry coupled to the external cabling and configured to sense a magnetic flux in the transformer core when the external cabling forms the external winding around the transformer core; and power supply circuitry coupled to the external cabling and configured to supply power to the internal unit via the transformer core when the sensing circuitry is sensing the magnetic flux in the transformer core, and the magnetic flux is below a predefined threshold flux.

9. The external unit according to claim 8, further comprising processing circuitry configured to: activate the sensing circuitry; acquire, from the sensing circuitry, a signal indicative of a sensed value indicating the magnetic flux in the transformer core; compare the sensed value with a stored value indicative of the threshold magnetic flux; and control the power supply circuitry to supply power to the internal unit via the transformer core when the comparison indicates that the magnetic flux in the transformer core is lower than the threshold magnetic flux.

10. The external unit according to claim 9, wherein: the external unit further comprises an indicator for providing an indication to an operator; and the processing circuitry is further configured to control the indicator to provide a predefined indication when power is being provided by the external unit to the internal unit.

11. The external unit according to claim 8, wherein the external cabling comprises: a connector including a first connector part and a second connector part; a first conductive current path between the power supply circuitry and the first connector part, conductively connecting the first connector part and the power supply circuitry; a second conductive current path between the power supply circuitry and the second connector part, conductively connecting the second connector part and the power supply circuitry; and a third conductive current path between the first connector part and the second connector part, conductively connecting the first connector part and the second connector part, wherein the first connector part and the second connector part are joinable to conductively connect the first conductive current path to the second conductive current path via the third conductive current path so that a second winding can be formed around the transformer core by joining the first connector part and the second connector part.

12. A medical system comprising: an internal unit for implantation into a body of a patient; a transformer core to be arranged under the skin of the patient; internal cabling connecting the internal unit and the transformer core, the internal cabling comprising an internal winding around the transformer core; and the external unit according to claim 8.

13. The medical system according to claim 12, wherein the internal unit is a cochlear implant, an auditory transmodiolar implant, an auditory brainstem implant, a bone conduction hearing aid, a middle ear implant, an artificial pacemaker, a blood pumping impeller, a ventricular assist device (VAD), a total artificial heart, an eye implant or retina implant, a nerve stimulator, a deep brain stimulator, a drug delivery system, a brain computer interface system, a cardioverter defibrillator, a gastric stimulator, a brain computer interface system or a rechargeable battery.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing an example embodiment of the invention, wherein:

[0041] FIG. 1 illustrates the external unit of a medical system with sensing circuitry configured to sense a magnetic flux in the transformer core, according to an embodiment of the invention;

[0042] FIG. 2 illustrates the flowchart to activate the sensing circuitry according to an embodiment of the invention;

[0043] FIG. 3 illustrates a medical system according to an embodiment of the invention;

[0044] FIG. 4A illustrates a first external unit of a medical system forming an external winding connected to the body of a patient and a second external unit not connected to the body according to an embodiment of the invention;

[0045] FIG. 4B illustrates a first external unit of a medical system and a second external unit connected to the body of a patient according to an embodiment of the invention;

[0046] FIG. 4C illustrates a first external unit of a medical system forming an external winding just disconnected from the body of a patient and a second external unit connected to the body of a patient according to an embodiment of the invention; and

[0047] FIG. 5 illustrates an external unit of a medical system providing a predefined indication when power is being provided by the external unit to the internal unit according to an embodiment of the invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0048] In the present detailed description, various embodiments of the method, external unit and medical system according to the present invention are mainly described with reference to a heart pump. It should be noted that this by no means limits the scope of the present invention as defined by the claims, which also encompass, for instance, implantable hearing aids, implantable pacemakers, defibrillators, eye implants, retina implants, heart pumps, ventricular assist devices, total artificial hearts, drug delivery systems, gastric implant, nerve stimulators, brain stimulators, functional electrical stimulation devices, such as cochlear prostheses, organ assist or replacement devices, and other partially or completely-implanted medical devices.

[0049] FIG. 1 illustrates the medical system 100 according to an embodiment of the invention. The medical system comprises an internal unit 106 implanted into a body of a patient; a transformer core 112 arranged under the skin 107 of the patient; and internal cabling 108 connecting the internal unit and the transformer core 112, the internal cabling comprising an internal winding around the transformer core, wherein the external unit comprises external cabling 104 including an external winding around the transformer core to allow supply of power from the external unit 109 to the internal unit 106 via the transformer core 112. Further the external cabling comprises: a connector 119 including a first connector part 114 and a second connector part 115, a first conductive current path 117 between the power supply circuitry 103 and the first connector part 114, conductively connecting the first connector part 114 and the power supply circuitry 103, a second conductive current path 116 between the power supply circuitry 103 and the second connector part 115, conductively connecting the second connector part 115 and the power supply circuitry 103 and a third conductive current path 118 between the first connector part 114 and the second connector part 115, conductively connecting the first connector part 114 and the second connector part 115, wherein the first connector part 114 and the second connector part 115 are joinable to conductively connect the first conductive current path 117 to the second conductive current path 116 via the third conductive current path 118 so that a second winding can be formed around the transformer core 112 by joining the first connector part 114 and the second connector part 115. Further the external cabling is formed through a pierced healed skin tunnel 110 of a patient 111. By using time multiplexing control, the power circuitry 103 is disconnected from the external cabling 104 using connection means 105. Further one measures and evaluates, using the sensing circuitry 101 connected to the external cabling 104, the induced voltage in the external cabling winding caused by the time varying magnetic flux 102 in the transformer core 112, using the principle of Faraday's law i.e. the time varying magnetic flux in the transformer core will generate an induced voltage in the sensing circuitry 101. By evaluating the measured induced voltage, which is a signal indicative of the time varying magnetic flux in the transformer core, one can decide to, when signal indicates that the time varying magnetic flux in the transformer core is below a predefined threshold flux, provide power to the internal unit 106 by the external unit 109 via the transformer core 112. The power is provided by closing the connection means 105 and providing a time varying current in the external cabling 104. In FIG. 1 the external winding contains two turns.

[0050] FIG. 2 illustrates the flowchart 200 of the processing circuitry configured to activate the sensing circuitry according to an embodiment of the invention. The sensing circuitry is activated to sense the time varying magnetic flux in the transformer core. The sensing circuitry returns a sensed value related to the amount of time varying magnetic flux in the transformer core. The sensed value is then compared with a stored value indicative of the threshold magnetic flux. If the sensed value is lower than the stored value the power supply circuitry is activated to supply power to the internal unit via the transformer core.

[0051] FIG. 3 illustrates the same medical system 100 as in FIG. 1 but in a different view, according to an embodiment of the invention. The medical system comprises the internal unit 106 implanted into a body of a patient; a transformer core 112 arranged under the skin 107 of the patient; and internal cabling 108 connecting the internal unit and the transformer core 112, the internal cabling comprising an internal winding around the transformer core. The external unit comprises external cabling 104 including an external winding around the transformer core to allow supply of power from the external unit 109 to the internal unit 106 via the transformer core 112. The external cabling 104 has an openable and closable connector 119. To mount the external unit 109 the external cabling connector is opened and is fed through a pierced healed skin tunnel 110 of a patient 111. Then the connector is closed forming the external winding. After the connector 119 is closed the external unit 109 evaluates a signal indicative of a magnetic flux in the transformer core. Because no other external units are connected the time varying magnetic flux in the transformer core 112 is zero i.e. it is below a predefined threshold flux. Because it is below the threshold flux the external units starts to provide power to the internal unit 106 by the external unit 109 via the transformer core 112.

[0052] FIG. 4A It will now be explained how a seamless exchange of the external unit is made, according to an embodiment of the invention. A first medical device has an external winding 104, connected to the patient, around the implanted transformer core 112 supplying power from the external unit 109 to the internal unit 106 via the transformer core 112. The power supplied by the external unit 109 is characterized by a time varying current inducing magnetic flux in the transformer core. A secondary external unit 401 with an opened connector 119 is positioned closed to the first external unit.

[0053] FIG. 4B The next step is that the second external unit 401 is connected to the patient by feeding the external cabling through the pierced healed skin tunnel 110 of a patient 111. Then the connector 119 is closed forming a secondary external winding around the transformer core. The external unit 109 is at this moment transferring energy from the external unit 109 to the internal unit 106 via the transformer core 112. The secondary external unit 401 is activated and starts to measure and to evaluate a signal indicative of a magnetic flux in the transformer core using the sensing circuitry 101. Since the external unit 109 is transferring energy creating a magnetic flux in the transformer core 112 the secondary unit 401 senses that signal indicating that the magnetic flux in the transformer core is above a predefined threshold flux. Thus, the secondary unit 401 does not provide any power to the internal unit 106 instead it continues to evaluate the signal indicative of a magnetic flux in the transformer core.

[0054] FIG. 4C The next step is that the external unit 109 is disconnected by opening the connector 119 and removing the external cabling from the pierced healed skin tunnel 110 of the patient 111. Since the external unit 109 then stops transferring energy there is no more a magnetic flux in the transformer core 112. The secondary unit 401 which measures the signal indicative of a magnetic flux in the transformer core drops below the predefined threshold flux starts to provide power to the internal unit 106 via the transformer core 112. Thus, a seamless switch of external units has been made without any interruption of the power supply to the internal unit.

[0055] FIG. 5 illustrates the indicator of external unit 109 of a medical system according to an embodiment of the invention. The external unit 109 comprises a LED indicator 501 for providing an indication to an operator or the patient when power is being provided by the external unit to the internal unit.

[0056] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.