MONITORING UNIT AND HIGH FREQUENCY SURGERY SYSTEM HAVING SUCH A MONITORING UNIT

Abstract

A monitoring unit which is configured to monitor a patient during an operation of a high-frequency surgery device, wherein the high-frequency surgery device is configured to separate and/or coagulate biological tissue by means of high-frequency electrical energy, wherein the monitoring unit has: measuring electrodes which are disposed in a periphery of the patient, and an evaluation and control unit which is configured to impress a predetermined measuring alternating voltage or a predetermined measuring alternating current on the measuring electrodes, and to monitor an impedance decreasing between the measuring electrodes and to monitor a time curve of the impedance and/or to monitor a temporal change thereof

Claims

1-21. (canceled)

22. A monitoring unit configured to monitor a patient during an operation of a high-frequency surgery device, wherein the high-frequency surgery device is configured to separate and/or coagulate biological tissue by means of high-frequency electrical energy, the monitoring unit comprising: measuring electrodes adapted to be disposed in a periphery of the patient; and an evaluation and control unit configured to impress a predetermined measuring alternating voltage or a predetermined measuring alternating current on the measuring electrodes, and to monitor an impedance decreasing between the measuring electrodes, to monitor (a) a time curve of the impedance, (b) a temporal change thereof or (c) both the time curve of the impedance and the temporal change thereof

23. The monitoring unit according to claim 22, wherein the evaluation and control unit is further configured to generate a warning signal if a relative change in impedance in the time curve of the impedance undercuts or exceeds a predetermined first limit value and/or the impedance undercuts a predetermined second limit value.

24. The monitoring unit according to claim 23, wherein the measuring electrodes are disposed on several components in the periphery of the patient, such that the evaluation and control unit is configured to determine a spatial impedance distribution in the periphery of the patient.

25. The monitoring unit according to claim 24, wherein the monitoring unit further has a display and wherein the evaluation and control unit is configured to display the warning signal in the form of a spatial position and location of a place in the periphery of the patient at which the first limit value is exceeded or undercut and/or the second limit value is undercut on the display.

26. The monitoring unit according to claim 25, wherein the measuring electrodes form a pattern of surface electrodes which are spatially distributed, adjacent and electrically insulated from each other and wherein the evaluation and control unit is configured to measure the impedance between each two adjacent surface electrodes.

27. The monitoring unit according to claim 26, wherein the measuring electrodes are realized in the form of an interdigital structure and wherein the predetermined measuring alternating voltage or the predetermined measuring alternating current has a frequency of 1 kHz to 10 kHz and/or does not correspond to a frequency by means of which the high-frequency surgery device is operated.

28. The monitoring unit according to claim 25, wherein the measuring electrodes are disposed such that they are in electroconductive contact with one or several body locations and/or clothing of the patient

29. The monitoring unit according to claim 28, wherein a number of measuring electrodes is at least larger than a number of the one or several body location(s) of the patient to be monitored.

30. The monitoring unit according to claim 22, wherein the measuring electrodes are disposed on a surface of a patient table or integrated in the surface of the patient table.

31. The monitoring unit according to claim 30, wherein the measuring electrodes are incorporated in a removable cover of a patient table.

32. The monitoring unit according to claim 31, wherein the measuring electrodes each have electroconductive threads which are woven into the cover.

33. The monitoring unit according to claim 32, wherein the measuring electrodes are metrologically differentially connected in series or in parallel or inductively or capacitively coupled to each other and, preferably in their entirety, serve as a dispersive electrode of the high-frequency surgery device which discharges the high-frequency electrical energy from the biological tissue.

34. The monitoring unit according to claim 33, wherein impressing the predetermined measuring alternating voltage or the predetermined measuring alternating current on the measuring electrodes takes place on the basis of a four-wire measurement.

35. The monitoring unit according to claim 30, wherein the measuring electrodes are electronically connected to each other as pairs of electrodes, such that impressing the predetermined measuring alternating voltage or the predetermined measuring alternating current and the measurement of the impedance is carried out in pairs, wherein each individual measuring electrode of the measuring electrodes is pairable with any other measuring electrode of the measuring electrodes, and wherein the measurement of the impedance per pair of measuring electrodes is preferably performed successively in time or simultaneously.

36. The monitoring unit according to claim 35, wherein the evaluation and control unit is configured to measure a real part and/or imaginary part of the impedance decreasing over the measuring electrodes and/or to measure an amplitude and phase of the measuring alternating voltage or the measuring alternating current.

37. A monitoring unit, which is configured to monitor a patient during operation of a high-frequency surgery device, wherein the high-frequency surgery device is configured to separate and/or coagulate biological tissue by means of high-frequency energy, the monitoring unit comprising: measuring sensors; and an evaluation and control unit, wherein the measuring sensors are configured to detect a parameter which is caused during the separation and/or coagulation of the biological tissue because of the high-frequency energy.

38. The monitoring unit according to claim 37, wherein the measuring sensors are temperature sensors, preferably thermoactive elements, which are disposed in a periphery of the patient and configured to detect a temperature as the parameter, and wherein the evaluation and control unit is preferably configured to generate a warning signal if a relative change in temperature exceeds a predetermined first threshold.

39. The monitoring unit according claim 37, wherein the temperature sensors are disposed on several components in the periphery of the patient, such that the evaluation and control unit is configured to determine a spatial temperature distribution in the periphery of the patient.

40. The monitoring unit according to claim 37, wherein the measuring sensors are each magnetic and/or electric antennas which are each configured to detect electromagnetic measuring signals from the periphery of the patient as the parameter, the measuring signals being generated by the high-frequency energy during operation of the high-frequency surgery device, and wherein the evaluation and control unit is configured to calculate a spatial distribution of electric current density from the electromagnetic measuring signals by solving a mathematical inverse problem.

41. A high-frequency surgery system, comprising: a high-frequency generator configured to generate a high-frequency energy; a high-frequency surgery device having an active electrode and a dispersive electrode, wherein at least the active electrode is connected to the high-frequency generator, wherein the active electrode is configured to separate and/or coagulate biological tissue by means of the high-frequency electrical energy, and wherein the dispersive electrode is configured to discharge the high-frequency electrical energy from the biological tissue; and a monitoring unit as set forth in claim 37.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0101] Embodiments of the invention are shown in the drawings and are described in more detail hereinafter.

[0102] FIG. 1 shows a schematic view of a first embodiment of a high-frequency surgery system according to the invention;

[0103] FIG. 2 shows a schematic view of a second embodiment of a high-frequency surgery system according to the invention;

[0104] FIG. 3 shows a schematic view of an impedance curve over time;

[0105] FIG. 4. shows a schematic view of an embodiment of the measuring electrodes;

[0106] FIG. 5 shows a schematic view of a second embodiment of the measuring electrodes;

[0107] FIG. 6 shows a schematic view of a third embodiment of the measuring electrodes; and

[0108] FIG. 7 shows a schematic view of a third embodiment of a high-frequency surgery system according to the invention.

DETAILED DESCRIPTION

[0109] FIG. 1 shows a schematic view of first embodiment of a high-frequency surgery system according to the invention. The high-frequency surgery system in its entirety is marked with reference sign 100. The high-frequency surgery system has an embodiment of a monitoring unit 10 according to the invention.

[0110] Monitoring unit 10 is configured to monitor a patient 12 during an operation of a high-frequency surgery device 14. In the present invention, high-frequency surgery device 14 is an electric scalpel with a monopolar design.

[0111] High-frequency surgery device 14 has an active electrode 16 and a dispersive electrode 18. Active electrode 16 is configured to separate and/or coagulate biological tissue of patient 12 by means of a high-frequency electrical energy or by feeding in a high-frequency alternating current. Dispersive electrode 18 is configured to discharge the high-frequency electrical energy from the biological tissue. In the present invention, dispersive electrode 18 is adhesively applied to a thigh of patient 12 as a surface electrode.

[0112] Active electrode 16 and dispersive electrode 18 are electronically coupled to a high-frequency generator 20 via one or several cable(s). High-frequency generator 20 is configured to convert an electric current from the electric grid (e.g., via a 230V, 16 A; or a 380V, 32 A connection) in a power-electronic manner (for example, by means of frequency converters) to a high-frequency alternating current required for operating the high-frequency surgery device. The frequency of this cutting current is preferably above 300 kHz and below 5 MHz. In other embodiments, dispersive electrode 18 can also be applied to other body parts of patient 12 or, alternatively, be formed by a ground connection of an operating table 22.

[0113] In the present invention, operating table 22 is a horizontal patient table which stands on a ground via a monolithic base 24. Preferably, the operating table is completely electronically insulated from an environment. In the present invention, the electric current fed from active electrode 16 into the tissue of patient 12 flows back to the grounded high-frequency generator via dispersive electrode 18 (as a mass in the electrical sense).

[0114] In the case shown in FIG. 1, however, not all the electric current injected into the patient's body by active electrode 16 flows off through the dispersive electrode because another conductivity bridge 26 is formed on a lower leg 28 of the patient, for example because of an improper handling on the part of the surgical staff when preparing the surgery or during the surgery. Conductivity bridge 26 is indicated in a simplified manner as a black spot on lower leg 28 of patient 12. An uncontrolled current flow over this conductivity bridge 26, which, in addition to dispersive electrode 18, represents an additional discharge possibility for the electric current, can cause burns in the affected areas of lower leg 28.

[0115] For a prediction or early detection of the formation of such parasitic conductivity bridges, high-frequency surgery system 100 has an embodiment of monitoring unit 10 according to the invention.

[0116] Monitoring unit 10 has measuring electrodes 30. In a simplified manner, only three of the plurality of measuring electrodes 30 are marked in the present invention. Measuring electrodes 30 are disposed in a direct periphery of patient 12 in the present invention. In this case, the peripheral arrangement of measuring electrodes 30 is limited to measuring electrodes 30 being disposed directly on a surface 32 of patient table 22. Measuring electrodes 30 are preferably each electrically insulated from one another. A drop in impedance between the measuring electrodes is caused by the current flow of the measuring alternating current through the tissue of patient 12 located between two measuring electrodes each. Measuring electrodes 30 are in direct contact with a skin of patient 12 who lies on patient table 22.

[0117] Furthermore, monitoring unit 10 has an evaluation and control unit 34. Evaluation and control unit 34 is configured to impress a predetermined measuring alternating voltage or a predetermined measuring alternating current on measuring electrodes 30. Furthermore, evaluation and control unit 34 is configured to measure, or to determine by means of current measurement or voltage measurement, an impedance Z (or an imaginary part X and/or a real part R) dropping between measuring electrodes 30. Furthermore, evaluation and control unit 34 is configured to monitor a time curve of impedance 36 (see FIG. 3) and/or a temporal change (∂Z/∂t) thereof and to generate an acoustic, optical and/or tactile warning signal if a relative change of the impedance (∂Z/∂t) in the time curve of the impedance 36 undercuts or exceeds a predetermined first limit value 38 and/or the impedance undercuts a predetermined second limit value 40 (cf. FIG. 3, in which time t in [s] is assigned to the abscissa, impedance Z in [Ohm] is assigned to the ordinate).

[0118] In the present invention, the warning signal is displayed on a display 42 or a display device which is connected to evaluation and control unit 34 via one or several cable(s). The display is disposed on an operation terminal 44 via which patient 12 is ventilated by means of a breathing hose 46 during the surgery.

[0119] FIG. 2 shows a second embodiment of high-frequency surgery system 100 with a second embodiment of monitoring unit 10. High-frequency surgery device 14 has a bipolar design of an electric scalpel in FIG. 2. With the bipolar design, active electrode 16 and dispersive electrode 18 are disposed in the manner of forceps with two branches insulated from one another, for example, wherein the active-neutral assignment can swap between the branches during operation.

[0120] Monitoring unit 10 has measuring sensors 48. Measuring sensors 48 are disposed in the periphery of patient 12. In the present invention, measuring sensors 48 are disposed over the entire surface 32 of patient table 22 so as to be at a distance to one another. Furthermore, additional measuring sensors are disposed on breathing hose 46. Measuring sensors 48 are configured to detect a parameter which is produced during the separation and/or coagulation of the biological tissue because of the high-frequency energy. Evaluation and control unit 34 is configured to generate a warning signal based on the parameter.

[0121] In the present invention, measuring sensors 48 are temperature sensors, in particular thermoelectric elements, such as thermocouples. The measured parameter is a temperature difference in Kelvin. If a parasitic current flow occurs over an additional conductivity bridge (see FIG. 1), a rise in temperature can be measured in the form of a temperature difference via temperature sensors 48. If the temperature difference measured in time exceeds a first threshold in the form of a maximum temperature T.sub.Max, the warning signal is generated.

[0122] FIGS. 4 and 5 show two exemplary embodiments of advantageous arrangements of measuring electrodes 30. FIG. 4 shows a checkered arrangement of black and white measuring electrodes 30. The impedance can be measured between two adjacent electrodes each, but in principle also between any two pairs of positive-negative electrodes in the checkerboard arrangement, in which the measuring electrodes 30 form a pattern of spatially distributed surface electrodes, each adjacent to and preferably electrically insulated from one another. FIG. 5 shows what is known as an interdigital structure.

[0123] FIG. 6 shows an embodiment of measuring electrodes 30 which are incorporated in, e.g., woven into, a fabric in the form of metallic threads, for example. Shown fabric 49 can be made of a non-conductive cloth or polyester and have a plurality of interwoven and/or interlaced threads, for example. Some of these threads serve as measuring electrodes 30 in metallic or electrically conductive versions (e.g. carbon-based). For example, a chair or table cover for patient table 22 can be made of such a fabric. Alternatively, a (support) mat can also be made of such a fabric. Depending on how the metallic threads or measuring electrodes are woven in, a checkerboard arrangement of the electrodes can also be created.

[0124] In FIG. 6, schematic impedance measurements are marked as arrows between respective measuring electrodes 30. In the present invention, impedances Z.sub.1 to Z.sub.4 are measured indirectly via a current measurement or voltage measurement by evaluation and control unit 20. Impedance Z.sub.4 is not measured directly between two adjacent measuring electrodes 30; instead, a measuring electrode has been skipped between measuring electrodes 30.

[0125] FIG. 7 shows a third embodiment of the high-frequency surgery system 100 with a third embodiment of monitoring unit 10. As measuring sensors 48, monitoring unit 10 has magnetic and/or electric antennas 50. Antennas 50 are each configured to detect electromagnetic signals 52 from the periphery of patient 12 as the parameter, electromagnetic signals 52 being generated by the high-frequency energy during the operation of high-frequency surgery device 14.

[0126] Evaluation and control unit 34 is configured to calculate a spatial distribution of electric current density from the electromagnetic measuring signals by solving a mathematical inverse problem; the detected measuring signals with magnetic antennas 50 being proportional to 1/distance.Math.∂I/∂t; the detected measuring signals with electric antennas 50 being proportional to 1/distance.Math.∂V/∂t. Antennas 50 are preferably disposed in a direct operating environment, for example on patient table 22 and/or on a ceiling over the surgical procedure and/or in corners of the operating room. In the present invention, six antennas 50 are schematically shown, of which only one has been marked for reasons of clarity.

[0127] Furthermore, a method for monitoring a patient 12 during an operation of a high-frequency surgery device 14 is particularly preferred, wherein the high-frequency surgery device 14 is configured to separate and/or coagulate biological tissue by means of high-frequency electrical energy. The method comprises the following steps: impressing a predetermined measuring alternating voltage or a predetermined measuring alternating current on measuring electrodes 30 which are disposed in a periphery of patient 12, and measuring an impedance decreasing between measuring electrodes 30, and monitoring a time curve of impedance 36 and/or a temporal change thereof.

[0128] Also preferred as an alternative solution is a method for monitoring a patient 12 during an operation of a high-frequency surgery device 14, wherein high-frequency surgery device 14 is configured to separate and/or coagulate biological tissue by means of high-frequency electrical energy. The method comprises the following steps: detecting electromagnetic measuring signals from a periphery of the patient by means of magnetic and/or electric antennas, wherein the electromagnetic measuring signals are generated by the high-frequency energy during the operation of the high-frequency surgery device; and calculating a spatial distribution of electric current density (or of the patient and their periphery) from the electromagnetic measuring signals by solving a mathematical inverse problem.

[0129] The preferred methods for monitoring a patient 12 during an operation of a high-frequency surgical device 14 can be designed in a respective method-specific variation according to the configurations and embodiments disclosed above without being mentioned here redundantly.