SENSORY PERCEPTION SURGICAL SYSTEM FOR ROBOT-ASSISTED LAPAROSCOPIC SURGERY

Abstract

The present invention proposes a sensory perception system for robot-assisted laparoscopic surgery. The invention comprises an electrosurgical forceps coupled to a surgical tool, an electrocautery radiofrequency signal generator and an impedance measurement circuit. The latter includes a measurement sensor for measuring a signal indicative of a magnitude corresponding to the value of contact impedance between the forceps and a patient's tissue; an oscillator; a first electrical circuit with resistors and a voltage limiter for protecting the measurement sensor and the oscillator; and a second electronic circuit with switches. The sensor and the oscillator are connected to the forceps by means of a power cable of the surgical tool. A processor connected to the measurement circuit receives said measured signal and converts same into a force vector, the modulus of which is a function of the contact impedance being measured and the argument is a function of the trajectory being followed.

Claims

1. A sensory perception surgical system for robot-assisted laparoscopic surgery comprising: an electrosurgical forceps coupled to a surgical tool; an electrocautery radiofrequency signal generator electrically coupled to an impedance measurement circuit and configured to supply energy to the electrosurgical forceps; the impedance measurement circuit comprising g: a measurement sensor configured to measure a signal indicative of a magnitude corresponding to the value of a contact impedance between the electrosurgical forceps and a patient's tissue; an oscillator configured to provide a power signal to the measurement sensor; a first electrical circuit comprising one or more resistors and a voltage limiter configured to protect the measurement sensor and the oscillator, the measurement sensor and the oscillator being connected to the electrosurgical forceps by a power cable of the surgical tool; and a second electronic circuit comprising a first switch circuit configured to commutate between a connection and a disconnection of a power cabling of the electrocautery radiofrequency signal generator with respect to the power cable of the surgical tool, and a second switch circuit configured to for commutate between a connection and a disconnection of the electrocautery radiofrequency signal generator and the measurement sensor; and a radiofrequency detector comprising at least one capacitive or inductive sensor disposed on the power cabling and configured to automatically commutate the first switch circuit and the second switch circuit while supplying energy, and a processor operatively connected to the impedance measurement circuit and configured to receive the signal measured by the measurement sensor, the processor further configured to convert the signal into a force vector, the force vector being estimated as a reflected vector of the received signal, a modulus of the vector being a function of the contact impedance and an argument of the vector being defined by a trajectory followed by the surgical tool in the moment of contact.

2. (canceled)

3. The system according to claim 1, wherein the electrocautery radiofrequency signal generator is configured to supply the energy as both monopolar and bipolar energy.

4. The system according to claim 1, wherein the supplied energy is monopolar, the first switch circuit and the second switch circuit each includes a relay.

5. The system according to claim 1, wherein the supplied energy is bipolar, the first switch circuit and the second switch circuit each comprise at least two relays.

6. The system according to claim 1, further comprising a control unit comprising control elements operatively connected to the impedance measurement circuit and the electrocautery radiofrequency signal generator, the control elements cooperatively configured to control each of the impedance measurement circuit and the electrocautery radiofrequency signal generator.

7. The system according to claim 6, wherein the control elements comprise pedals and/or actuators/push buttons.

8. The system according to claim 6, wherein the processor is disposed in the control unit.

9. The system according to claim 1, wherein the electrosurgical forceps are coupled to the surgical tool using a set of pulleys and cables cooperatively configured to allow the opening or closing of the electrosurgical forceps and enable their mobility, at least one of the pulleys being arranged on an articulation shaft thereof.

10. The system according to claim 9, wherein the set of pulleys are disposed on three parallel shafts, each one of the three parallel shafts arranged in a diametrical position with respect to the surgical tool and to a body of the electrosurgical forceps.

11. A non-transitory computer readable medium comprising program code instructions that when executed by a processing unit of a sensory perception surgical system are configured to implement a method for estimating a reaction force vector perceived in a control unit of the sensory perception surgical system, the sensory perception surgical system comprising: an electrosurgical forceps coupled to a surgical tool, an impedance measurement circuit and an electrocautery radiofrequency signal generator electrically coupled to an impedance measurement circuit and operable for supplying energy to the electrosurgical forceps, the impedance measurement circuit including a measurement sensor, an oscillator, a first electrical circuit comprising one or more resistors and a voltage limiter, and a second electronic circuit comprising a first switch circuit and a second switch circuit, the method comprising: receiving a signal indicative of a magnitude corresponding to the value of a contact impedance between the electrosurgical forceps and a patient's tissue, measured by the measurement sensor; and converting the received signal into a force vector estimated as a reflected vector of the received signal, a modulus of the vector being a function of the contact impedance and an argument of the vector being defined by a trajectory followed by the surgical tool follows in the moment of contact.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The foregoing and other features and advantages will be better understood based on the following detailed description of several merely illustrative and non-limiting embodiments in reference to the attached drawings in which:

[0028] FIG. 1 illustrates a surgical system for robot-assisted laparoscopic surgery for detecting the properties of a tissue, according to an embodiment of the present invention.

[0029] FIGS. 2A-2C schematically illustrate different connection configurations of an electrocautery radiofrequency signal generator for working in monopolar mode (FIG. 2A) or bipolar mode (FIGS. 2B and 2C).

[0030] FIG. 3 illustrates in more detail the architecture of the system proposed for obtaining the contact impedance and the associated force vector, according to an embodiment of the present invention.

[0031] FIG. 4 illustrates another embodiment of the architecture of the system proposed for obtaining the contact impedance and the associated force vector.

[0032] FIGS. 5A and 5B show different views of the electrosurgical forceps coupled to the surgical tool. FIG. 5A shows a perspective view of a distal end of the surgical tool showing rotations G1 and G2 of the articulations thereof and axial rotation G3 of the surgical tool assembly. FIG. 5B shows the pulleys for the transmission of movements G1 and G2 and the arrangement of the actuator cables which also allow the opening or closing of the electrosurgical forceps through rotation G1.

[0033] FIGS. 6A-6D illustrate different views showing the path of the cables which transmit energy to the electrosurgical forceps for detecting contact with the tissue, where said path must be compatible with the limited space available between the different pulleys, and also allows carrying out rotations G1, G2, and G3.

[0034] FIGS. 7A-7C graphically depict the calculated force vector and the construction of the triangles for modeling the anatomy of the environment, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention provides a sensory perception surgical system for robot-assisted laparoscopic surgery and a method allowing obtaining the sensory return of the force exerted by a surgeon on a patient's tissue/tissues during a surgical intervention performed remotely based on an estimate of the force vector exerted by detecting the contact impedance with the tissue/tissues and on the trajectory taken.

[0036] With reference to FIG. 1, said figure shows an embodiment of the proposed system 1. In this embodiment, the system 1 comprises a robot-assisted system 100; a control unit 110; a laparoscopy tower 120 housing an electrocautery radiofrequency signal generator 300 and an impedance measurement circuit 301.

[0037] The robot-assisted system 100 is provided with robotic arms 101 which allow moving surgical tools 102, as well as a laparoscopic camera 103. The control unit 110 includes actuators/push buttons 111 and pedals 113 with which the surgeon can handle/control the robot-assisted system 100, the electrocautery radiofrequency signal generator 300, as well as the impedance measurement circuit 301. The control unit 110 also has a display screen 112.

[0038] The electrocautery radiofrequency signal generator 300, which can be any standard electrocauterization signal generator, is electrically connected to the impedance measurement circuit 301 by means of a power cable 314 and is operable for supplying energy to the electrosurgical forceps 104 (see FIGS. 2A-2C, for example) coupled to the surgical tools 102. The impedance measurement circuit 301 is electrically connected to the electrosurgical forceps 104 by means of another power cable 304. The power cable 304 is formed by two conductor cables 304a, 304b (see FIG. 6D), the path of which is compatible with the kinematics of the electrosurgical forceps 102, allowing the movements thereof in three rotations/axes (orientation and elevation movements, as well as opening and/or closing movements) to enable detecting contact with the tissue/tissues.

[0039] The electrocautery radiofrequency signal generator 300 can be electrically monopolar when the return circuit is the patient him/herself or the saline medium used (FIG. 2A), or it can be electrically bipolar (FIGS. 2B and 2C) if the current flows between the terminal element 250 (see FIGS. 5A-5B) of the electrosurgical forceps 104.

[0040] FIG. 2A shows a monopolar configuration. The impedance measurement circuit 301 only houses one cable, i.e., the outgoing power cable. The incoming cable, marked with the arrow, passes outside the impedance measurement circuit 301. FIG. 2B shows a first bipolar configuration. The double incoming and outgoing cable with two polarities, marked with arrows, exits the electrocautery radiofrequency signal generator 300 and passes through the impedance measurement circuit 301, wherein the return is taken back through a conducting cannula. FIG. 2C shows a second bipolar configuration. The cable with two conductor wires exiting the electrocautery radiofrequency signal generator 300 pass through the impedance measurement circuit 301 and travel along the inside thereof, one to each part of the electrosurgical forceps 104.

[0041] Now with reference to FIG. 3, said figure shows another embodiment of the proposed system 1, comprising in this case the electrosurgical forceps 104 coupled to the surgical tool 102 of the robot-assisted system 100; the impedance measurement circuit 301 for measuring the contact impedance with the environment 303 of the tissue/tissues; the electrocautery radiofrequency signal generator 300; and a computer system or device 311 formed by at least one processor for estimating the applied forces based on the measurement of the impedance.

[0042] The difficulty entailed by use of the electrocautery radiofrequency signal generator 300 to enable also measuring contact impedance lies in the fact that radiofrequency pulses having a very high voltage of between about 1000 and 3000 volts are used to enable carrying out electrocoagulation and electrocauterization. For this reason, the use or inclusion of the impedance measurement circuit 301 in the proposed system 1 makes the measurement of the impedance at a low voltage and current compatible with the high electrocoagulation and electrocauterization energy at a high voltage.

[0043] To achieve the mentioned compatibility, the impedance measurement circuit 301 includes a measurement sensor 310, particularly a low-voltage measurement sensor, for measuring the magnitude corresponding to the value of the contact impedance; an electronic module comprising two switch circuits 305, 306 for the connection/disconnection of the power cabling 314 with respect to the power cable 304, and for the connection/disconnection of the electrocautery radiofrequency signal generator 300 and the measurement sensor 310, respectively.

[0044] Likewise, the impedance measurement circuit 301 also includes an oscillator 209 to enable measuring the impedance without applying any current, however weak it may be, with a continuous component, on the patient. The oscillator 209 provides a signal having a low voltage, for example 6 V, and a medium frequency, for example 20 KHz, which is applied in a monopolar or bipolar manner to the surgical tool 102 through the second switch circuit 306, the contacts of which are usually kept closed. Said low voltage is normally not applied to the electrocautery radiofrequency signal generator 300 since the contact of the first switch circuit 305 is usually open.

[0045] In the embodiment of FIG. 3, each of the switch circuits 305, 306 comprises two relays A1, A2, B1, B2. This configuration is particularly useful when the energy supplied by the electrocautery radiofrequency signal generator 300 is bipolar. In other embodiments not illustrated in this case, and particularly when the energy supplied by the electrocautery radiofrequency signal generator 300 is monopolar, each of the switch circuits 305, 306 only includes one relay A1, B1.

[0046] In operation, when the surgeon applies the energy for carrying out electrocoagulation or electrocauterization, the contact of relay A1, or relays A1, A2 of the first switch circuit 305 must be closed, while at the same time the contact of relay B1, or relays B1, B2 of the second switch circuit 306 must be open. To that end, the system 1 also particularly includes a radiofrequency detector 313 having a capacitive or inductive sensor 312 on the power cable 314, which allows automatically commutating the first and second switch circuits 305, 306 while energy is being applied. Alternatively, this function may be performed by introducing the actuation signal of the pedals 113 connected to the electrocautery radiofrequency signal generator 300.

[0047] In the example of FIG. 3 and for the purpose of preventing damage in the electrocautery radiofrequency signal generator 300 and/or in the impedance measurement circuit 301, for example as a result of surges in the commutation of the relays, the system 1 is particularly protected with resistors 307 and a voltage limiter 308.

[0048] The signal/magnitude corresponding to the value of the impedance obtained by the measurement sensor 310 is treated by the processor 311 for conversion into a force vector, in which the force magnitude is given by the value of the impedance being measured and the argument of the vector is defined by the direction in space of the trajectory that the surgical tool 102 follows in the moment of contact and is controlled by the control unit 110 which is connected to the processor 311 through a communication channel 321.

[0049] FIG. 4 shows another embodiment of the proposed system 1. In this case, the system 1 is formed by the electrosurgical forceps 104 coupled to the surgical tool 102; the impedance measurement circuit 301 for measuring the contact impedance with the environment 303 of the tissue/tissues; and the computer system or device 311 comprising at least one processor. The impedance measurement circuit 301 includes the measurement sensor 310, the oscillator 309, and an electronic circuit formed by the resistors 307 and the voltage limiter 308. Compatibility with high external voltages like in the case of using the electrocautery radiofrequency signal generator 300 is therefore permitted.

[0050] Each surgical tool 102 (see FIGS. 5A and 5B) is made up of a cannula 201 supporting a first articulated element or body 202 which can carry out rotation G1 with respect to the end of the cannula 201 about shaft 204 actuated by a drum 207. The body 202 supports the terminal element 250 of the electrosurgical forceps 104 the orientation of which can be varied by carrying out rotation G2 with respect to the body 202 about shaft 206 actuated by means of drums 208 and 209.

[0051] Likewise, cables C1a, C1b, C2, C3, C4, and C5 and a set of pulleys 210, 211, 212, 213, 220, 221, 222, 223, 230, 231 allow transmitting the movement from drive means to which each surgical tool 102 is connected, and are adapted to enable carrying out rotation G1 about shaft 204, which entails a mechanical complexity that hinders the introduction of the electrical cables 304a and 304b. This mechanical complexity is of great relevance since the electrical conductors for measuring the impedance must share the smaller space available with the two cables C1a and C1b which transmit rotational movement G1 to the drum 207, and the four cables C2, C3, C4, and C5 which transmit the orientation and opening or closing of the electrosurgical forceps 104 by means of drums 208 and 209 (FIG. 5B).

[0052] To allow rotation G1 the mentioned set of pulleys 210, 211, 212, 213, 220, 221, 222, 223, 230, 231 is used, in which at least one, preferably all, of said pulleys is/are arranged on the articulation shaft thereof (FIG. 6A). Particularly, as observed in FIG. 6B, a set of pulleys is arranged for the four cables C2, C3, C4, and C5 which move the electrosurgical forceps 104, mounted on three parallel shafts 203, 204, and 205 in a diametrical position with respect to the cannula 201 and to the body 202 (FIG. 5B). The central shaft 204 joins the cannula 201 and the body 202, which allows carrying out rotation G1, and supports the 4 pulleys 220, 221, 222, and 223 joining the two pairs of antagonist cables transmitting the movement of the forceps, whereas the two shafts 203 and 205 support accompanying pulleys.

[0053] This arrangement of pulleys on three consecutive shafts for each cable that must go through articulation G1 offers a clear advantage over other embodiments, given that besides allowing the generation of a guided cable passage between consecutive pulleys, like in the case of pulleys 210 and 220 which create passage 214 (see FIG. 5C), constituting a secure guiding of the movement of each cable, two free spaces are created on pulleys 230 and 231 allowing the passage of the necessary electrical cable 304a and 304b to enable measuring the impedance.

[0054] The fact that all the pulleys are arranged on the central plane of the cannula 201 and of the body 202 allows the pulleys to have the largest possible diameter without exceeding the maximum gauge of the cannula 201. Likewise, with the 4+4+2 pulleys required for the transmission of movements having the largest possible diameter, the present invention allows reducing the radius of curvature of the different cables on the pulleys, improving the durability and reliability of the surgical tool 102. The electrical cable 304a and 304b going through the free spaces on the pulleys 230 is integral with cables C2 and C3, assuring that that it does not support any mechanical force when deflexion of the electrosurgical forceps 104 on axis G2 occurs (FIG. 6D).

[0055] The embodiments of the present invention also provide a sensory perception method for estimating or calculating the reaction force vector that must be perceived by the surgeon or the operator in the control unit 110, through the push buttons/actuators 111 and/or pedals 113, based on the value/magnitude of the obtained impedance.

[0056] FIGS. 7A-7C graphically illustrate an example of the foregoing. Given that there is no force sensor on the surgical tool 102 which allows the direct measurement of the contact force 410 (FIG. 7A), it is estimated indirectly by the processor 311 as a force vector. The force vector 411 is estimated as a reflected vector of the contact force 410, the modulus of which is equal to the modulus of the contact force 410, whereas the argument thereof is defined by being on the same plane 416, and which is defined by the two passage points 414 and 415 before the perceived contact point, the normal 412 of the contact surface 413, and an angle of reflection 418 that is equal to the angle incidence 417.

[0057] The contact surface 413 which allows carrying out positioning calculations in space of the reflected vector is not known. Therefore, the proposed method obtains an approximation of the configuration of the surface of the anatomical elements of the environment by performing modeling 400 in a three-dimensional space. To that end, the method comprises generating a triangulation 402 (i.e., generating a series of triangles 403) from the contact points 404 that are perceived throughout the operation, by means of joining same. Each new perceived contact point 404 (FIG. 9C) causes a triangle 403 to be broken down into new triangles 405 and 406. In this manner, the environment modeling resolution which allows obtaining the argument of the force vector 411, which is applied as a reaction force on the controls of the control unit 110 and generates the sensory return to the surgeon/operator, progressively increases.

[0058] The proposed invention can be implemented in hardware, software, firmware, or any combination thereof. If it is implemented in software, the functions can be stored in or coded as one or more instructions or code in a computer-readable medium.

[0059] The scope of the present invention is defined in the attached claims.