Gripping tool with coagulation function

Abstract

The present invention is entitled "Gripping Tool with Coagulation Function". In one embodiment, a medical system includes a medical device and a processing circuit. The medical device has a gripper head, an actuator, and a proximity sensor. The gripper head includes complementary first and second grippers and first and second conductive surfaces disposed on respective distal portions of the first and second grippers, the conductive surfaces being electrically insulated from each other in the gripper head. The actuator is configured to close the grippers so as to bring the conductive surfaces into contact with tissue of a body part of a living subject. The proximity sensor is configured to output at least one proximity signal in response to a displacement between the grippers. The processing circuit is coupled to sense the displacement between the first and second grippers in response to at least one proximity signal, and to apply a current between the first and second conductive surfaces of the grippers when the sensed displacement is less than a given threshold displacement.

Description

[0001] Related application information

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 835,916, filed on April 18, 2019, whose inventors are Govari et al. Technical Field

[0003] The present invention relates to medical tools and particularly, but not exclusively, to grasping tools. Background Art

[0004] Graspers can be used in medical applications to grasp, remove and / or cut tissue, which often results in heavy bleeding. Blood coagulation in surgery can be performed by applying an electric current to the bleeding tissue.

[0005] For example, U.S. Patent No. 5,810,809 to Rydell describes an arthroscopic instrument for debridement of tissue that includes an electrocautery electrode for achieving hemostasis at the surgical site. The drive motor of the debridement instrument is located remotely from the handle of the instrument, and even if the arthroscopic procedure is performed under saline, means are provided to electrically isolate the handle from the drive motor and associated power supply.

[0006] U.S. Patent 8,702,702 issued to Edwards et al. describes a mechanical cutting device that utilizes mechanical (rotational) motion and suction to engage tissue and also applies cutting energy sufficient to vaporize the tissue. Rotation and suction are used to engage tissue (when the cutting windows of the inner and outer blades are aligned, the tissue is sucked into the cutting window), and then the cutting member acts as an electrode by applying an electrical cutting signal thereto so that when the cutting members rotate relative to each other, the cutting member electrically cuts the tissue. The electrical cutting signal is only applied when the windows are aligned until tissue cutting is completed. The cutting signal preferably stops after the cutting window becomes misaligned. When the cutting window is misaligned, a coagulation signal can be provided to the cutting member so that the device acts as an electrocautery device.

[0007] U.S. Patent Publication 2014 / 0148729, inventors Schmitz et al., describes a method for removing at least a portion of a brain tumor and may first include contacting a forward tissue cutter disposed at a distal end of a tissue removal device with the brain tumor. The tissue removal device may include a shaft having a diameter of no greater than about 10 mm, and in some embodiments, the tissue cutter does not extend laterally beyond the diameter of the shaft. The method may then involve cutting tissue from the brain tumor using the tissue cutter. The method may then involve moving the cut tissue through a channel of the shaft in a direction from the distal end of the tissue removal device toward the proximal end of the device.

[0008] European Patent Publication EP0913126 to Kese et al. describes open surgical and endoscopic versions of a combined bipolar electrosurgical cutting and grasping instrument in which the grasping surface is contained within the shape of a standard surgical scissors. This unique arrangement creates a combined scissors and grasper that has the appearance of a standard pair of scissors but allows the surgeon to cauterize tissue and blood vessels while cutting and grasping, making the instrument well suited for performing vascular anastomosis. Summary of the invention

[0009] According to an embodiment of the present disclosure, a medical system is provided, which includes a medical device and a processing circuit. The medical device includes a gripper head, an actuator, and a proximity sensor. The gripper head includes complementary first and second grippers and first and second conductive surfaces disposed on respective distal portions of the first and second grippers, the first and second conductive surfaces being electrically insulated from each other in the gripper head. The actuator is configured to close the grippers so that the first and second conductive surfaces contact the tissue of a body part of a living subject. The proximity sensor is configured to output at least one proximity signal in response to a displacement between the first and second grippers. The processing circuit is coupled to sense the displacement between the first and second grippers in response to at least one proximity signal, and when the sensed displacement is less than a given threshold displacement, a current is applied between the first and second conductive surfaces of the grippers.

[0010] Furthermore, according to an embodiment of the present disclosure, the proximity sensor includes two electrical contacts that are disposed on the grasper head and configured to contact each other when a displacement between the first gripper and the second gripper is less than a given threshold displacement.

[0011] Still further, according to an embodiment of the present disclosure, the respective electrical contacts are connected to the grasper head via respective springs.

[0012] Furthermore, in accordance with embodiments of the present disclosure, the grasper head includes at least one position tracking transducer configured to provide a position signal indicative of the position of the grasper head, and the processing circuit is configured to calculate the position of the grasper head in response to the position signal.

[0013] Furthermore, according to one embodiment of the present invention, the proximity sensor includes two position tracking transducers disposed in the grasper head and configured to provide corresponding position signals included in at least one proximity signal, the position signals indicating corresponding positions of the first gripper and the second gripper, and the processing circuit is configured to calculate a displacement between the first gripper and the second gripper in response to the corresponding position signals.

[0014] Further in accordance with an embodiment of the present disclosure, the system includes an irrigation pump, wherein the medical device includes an irrigation tube coupled to the irrigation pump, the irrigation pump being configured to pump fluid into the irrigation tube to cool the tissue.

[0015] Still further, in accordance with an embodiment of the present disclosure, a grasper head includes two elongated members having a first gripper and a second gripper, and a pin connecting the two elongated members to allow angular movement between the first gripper and the second gripper.

[0016] Furthermore, according to an embodiment of the present disclosure, the proximity sensor includes two electrical contacts disposed on two opposite sides of the two elongated members and configured to contact each other when a displacement between the first gripper and the second gripper is less than a given threshold displacement.

[0017] Furthermore, according to an embodiment of the present disclosure, the respective electrical contacts are connected to the elongated members via respective springs.

[0018] According to another embodiment of the present disclosure, a medical method is also provided, including: closing a first gripper and a second gripper of a grasper head of a medical instrument so that a first conductive surface and a second conductive surface provided on respective distal portions of the first gripper and the second gripper contact tissue of a body part of a living subject, the first conductive surface and the second conductive surface being electrically insulated from each other in the grasper head; outputting at least one proximity signal in response to a displacement between the first gripper and the second gripper; sensing the displacement between the first gripper and the second gripper in response to the at least one proximity signal; and applying a current between the first and second conductive surfaces of the gripper when the sensed displacement is less than a given threshold displacement.

[0019] Furthermore, according to an embodiment of the present disclosure, the method includes contacting the two electrical contacts with each other when a displacement between the first gripper and the second gripper is less than a given threshold displacement.

[0020] Still further, according to an embodiment of the present disclosure, the respective electrical contacts are connected to the grasper head via respective springs.

[0021] Additionally, in accordance with an embodiment of the present disclosure, the method includes providing a position signal indicative of a position of the grasper head, and calculating the position of the grasper head in response to the position signal.

[0022] Furthermore, according to one embodiment of the present disclosure, the method includes two position tracking transducers disposed in a grasper head, providing corresponding position signals indicating corresponding positions of the first gripper and the second gripper included in at least one proximity signal, and calculating a displacement between the first gripper and the second gripper in response to the corresponding position signals.

[0023] Additionally, according to an embodiment of the present disclosure, the method includes pumping a fluid into an irrigation tube of the medical device to cool the tissue.

[0024] Technical solution 1. A medical method, comprising:

[0025] closing a first gripper and a second gripper of a grasper head of a medical device so as to bring a first conductive surface and a second conductive surface disposed on respective distal portions of the first gripper and the second gripper into contact with tissue of a body part of a living subject, the first conductive surface and the second conductive surface being electrically insulated from each other in the grasper head;

[0026] outputting at least one proximity signal in response to displacement between the first gripper and the second gripper;

[0027] Responsive to the at least one proximity signal, sensing the displacement between the first gripper and the second gripper; and

[0028] When the sensed displacement is less than a given threshold displacement, a current is applied between the first conductive surface and the second conductive surface of the gripper.

[0029] Technical Solution 2. The method according to Technical Solution 1 also includes two electrical contacts contacting each other when the displacement between the first gripper and the second gripper is less than the given threshold displacement.

[0030] Technical Solution 3. A method according to Technical Solution 2, wherein corresponding ones of the electrical contacts are connected to the grasper head via corresponding springs.

[0031] Technical Solution 4. The method according to Technical Solution 1 further includes: providing a position signal indicating the position of the grasper head; and calculating the position of the grasper head in response to the position signal.

[0032] Technical Solution 5. The method according to Technical Solution 1 also includes: two position tracking transducers arranged in the grasper head, providing corresponding position signals indicating the corresponding positions of the first gripper and the second gripper included in the at least one proximity signal; and calculating the displacement between the first gripper and the second gripper in response to the corresponding position signals.

[0033] Technical Solution 6. The method according to Technical Solution 1 also includes pumping fluid into the irrigation tube of the medical device to cool the tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0035] Figure 1 is a schematic diagram of a medical surgical system according to an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a magnetic field radiation component used in a medical surgery system according to an embodiment of the present invention;

[0037] Figure 3 is a schematic diagram of a medical device according to an embodiment of the present invention;

[0038] Figure 4-6 yes Figure 3 Various schematic diagrams of the distal end of the medical device are shown;

[0039] Figure 7 is a schematic diagram of a grasper head according to a first alternative embodiment of the present invention;

[0040] Figure 8 is a schematic diagram of a grasper head according to a second alternative embodiment of the present invention; and

[0041] Fig. 9 To include Figure 1 Flow chart of exemplary steps in a method of operating a system. DETAILED DESCRIPTION

[0042] Overview

[0043] As mentioned above, graspers can be used in medical applications to grasp, remove and / or cut tissue, which often results in heavy bleeding. Blood coagulation during surgery can be performed by applying an electrical current to the bleeding tissue.

[0044] The geometry and mechanical structure of the medical device may complicate the use of the medical device for coagulation. For example, if the medical device includes many conductive surfaces, the applied current may be limited due to short circuits caused by the metal surfaces.

[0045] Embodiments of the present invention include a system including a medical device for grasping tissue and automatically applying an electric current to the grasped tissue in response to the tissue being grasped, thereby performing coagulation when the tissue may bleed. The electric current is automatically applied in response to grasping the tissue based on sensing displacement between complementary grippers of a grasper head of the medical device. Automatically applying the electric current prevents the physician from forgetting to perform coagulation each time the tissue is grasped, and also allows the physician to focus on other tasks at hand.

[0046] The gripper includes a conductive surface through which an electrical current is applied to the tissue. The conductive surface is electrically connected to the processing circuit, but the conductive surfaces are electrically insulated from each other in the grasper head. Such electrical insulation can be achieved by forming at least a portion of the grasper head or at least a portion of the gripper from an insulating material, such as a biocompatible plastic. In some embodiments, the grasper head and / or the gripper can be formed of a conductive material, such as a biocompatible plastic, coated with an insulating material.

[0047] In some embodiments, the grasper head includes two elongated members having grippers, and a pin connecting the two elongated members to allow angular movement between the grippers.

[0048] The medical device includes an actuator to close the gripper to bring the conductive surface into contact with tissue of a body part of a living subject.

[0049] The grasper head also includes at least one position tracking transducer that provides a position signal indicative of the position of the grasper head. The processing circuit calculates the position of the grasper head based on the position signal. Based on the calculated position, a representation of the grasper head in the body part can be displayed on the display screen. The physician can then guide the grasper head within the body part based on the displayed representation of the grasper head.

[0050] The grasper head includes a proximity sensor that outputs one or more proximity signals in response to displacement between the grippers.

[0051] In some embodiments, the proximity sensor comprises two electrical contacts disposed on the grasper head. The electrical contacts contact each other when the displacement between the grippers is less than a given threshold displacement, such as about 2 mm or in the range of 1 mm-4 mm. The electrical contacts may be connected to the grasper head via corresponding springs.

[0052] In some embodiments, the proximity sensor comprises two electrical contacts disposed on two opposite sides of the two elongated members. When the displacement between the grippers is less than a given threshold displacement, the electrical contacts contact each other. The electrical contacts may be connected to the elongated members via respective springs.

[0053] In some embodiments, the proximity sensor includes two position tracking transducers disposed on the grasper head. The position tracking transducers provide position signals indicating the position of the grippers. The processing circuit calculates the displacement between the grippers in response to the position signals.

[0054] The processing circuit is coupled to sense the displacement between the grippers in response to the proximity signal. Sensing the displacement may be based on the two electrical contacts contacting each other. Alternatively, sensing the displacement may be performed by calculating the displacement between the grippers.

[0055] When the sensed displacement is less than a given threshold displacement, the processing circuit applies a current between the conductive surfaces of the gripper. The processing circuit may apply the current between the conductive surfaces as a result of the two electrical contacts contacting each other, thereby closing the circuit, causing the current to flow. Alternatively, the processing circuit may apply the current in response to the calculated displacement being less than a given threshold displacement.

[0056] The system may further include an irrigation pump and an irrigation tube disposed in the medical device. The irrigation tube is coupled to the irrigation pump. The irrigation pump pumps fluid into the irrigation tube to cool the tissue heated by applying the current.

[0057] System Description

[0058] Turning now to the drawings, according to an embodiment of the present invention, reference is now made to Figure 1 , which is a schematic diagram of the medical surgical system 20, and reference Figure 2 , which is a schematic diagram of a magnetic field radiating component location pad 24 used in system 20. The medical surgical system 20 is typically used during invasive and / or exploratory surgery on the sinuses or other body parts (such as the brain) of a patient 22.

[0059] For this procedure, the component 24 can be positioned behind and / or around the head of the patient 22, for example, by fixing the magnetic field radiation component 24 to a chair 25 (or bed) on which the patient sits (or lies). The magnetic field radiation component 24 in the illustrated example includes five magnetic field radiators 26 fixed in a horseshoe-shaped frame, which is positioned under or around the patient 22 so that the magnetic field radiators 26 surround the head of the patient 22. Alternatively, a smaller or larger number of radiators 26 in various configurations can be used. The magnetic field radiator 26 is configured to radiate an alternating magnetic field at a corresponding frequency into an area 30 where a body part is located, which is adjacent to the magnetic field radiation component 24 and includes the head of the patient 22.

[0060] The alternating magnetic field induces signals in the position tracking sensor 32 and the position tracking transducer 36. The position tracking transducer 32 is shown as being disposed on the medical device 28 so as to track the position of the medical device 28. The position tracking transducer 36 is shown as being disposed on the patient 22 (e.g., on the forehead of the patient 22 or any other suitable body part) so as to track the position of the patient 22 (e.g., to track the position of the head of the patient 22) to compensate for the movement of the patient relative to the magnetic field radiation component 24. By way of example only, the medical device 28 may include any one or more of the following: a probe for insertion into a body part, an endoscope, and / or a surgical tool such as an ENT tool, a suction tool, a micro-debrider, a razor, and / or a grasper.

[0061] The position of the distal end of the medical device 28 and the position of the patient 22 can be tracked using a tracking subsystem that tracks the position and orientation coordinates of the position tracking transducer 32 and the position tracking transducer 36 mounted at the distal end, respectively. The position tracking transducers 32, 36 are configured to output signals indicating the positions of the transducers 32, 36, respectively. The signals are processed by the tracking subsystem running on the processing circuit 38 to track the position of the distal end of the medical device 28 and the position of the patient 22 over time. In the embodiment where the tracking subsystem is a magnetic tracking subsystem, the position tracking transducer 32 and / or the position tracking transducer 36 include at least one coil, and typically include two or three orthogonally placed coils. In other embodiments, the tracking subsystem can be an electrical-based tracking subsystem that uses multiple head surface electrodes (e.g., multiple instances of the position tracking transducer 36) to track the position of the medical device 28 based on signals emitted by at least one electrode of the medical device 28 (included in the position tracking transducer 32). The tracking subsystem may be implemented using any suitable position tracking subsystem, such as, but not limited to, an ultrasound-based tracking system, wherein the position tracking transducer 32 includes at least one ultrasound transducer. Using the tracking subsystem, the physician 54 advances the distal end of the medical instrument 28 in the body part, as will be described in more detail below.

[0062] In some embodiments, the medical device 28 is attached to and held by a robotic arm 40 that is configured to manipulate the medical device 28. The robotic arm 40 includes a plurality of robotic joints configured to control movement of the robotic arm 40 and manipulate the medical device 28. In other embodiments, the medical device 28 is held and manipulated by a physician 54.

[0063] As described in more detail below, the position tracking transducer 32 is attached to the medical device 28, and determination of the position and orientation of the position tracking transducer 32 enables tracking of the position and orientation of the distal end 34 (or other location) of the medical device 28, which can be reversibly inserted into a body part of a patient 22 (a living subject).

[0064] Similarly, determination of the position and orientation of position tracking transducer 36 enables tracking of the position and orientation of a portion (e.g., the head) of patient 22. Position tracking transducer 36 is Figure 1 2 is shown as being disposed on the forehead of the patient 22. The position tracking transducer 36 may be disposed on any other suitable body part of the patient 22 in order to track the position / movement of the patient 22.

[0065] Systems for tracking an object inserted into a patient using a magnetic field radiator, such as magnetic field radiator 26, are described in U.S. Patent Publication 2016 / 0007842 to Govari et al. Also, a 3D-printed ... The system uses a tracking system similar to that described herein to find the position and orientation of the coil in an area irradiated by a magnetic field.

[0066] The robotic arm 40 typically has its own robotic coordinate system. The robotic coordinate system is aligned with the magnetic coordinate system of the magnetic field radiator 26, or vice versa. Alignment of the robotic coordinate system with the magnetic coordinate system can be performed, for example, by moving the robotic arm 40 or a medical device 28 attached to the robotic arm 40 to one or more known positions of the magnetic field radiator 26, such as to a position on the magnetic field radiating assembly 24 or to a position tracking transducer 36 or to one or more other known positions on the patient 22. Once alignment of the robotic coordinate system with the magnetic coordinate system has been performed, the position in the magnetic coordinate system can be translated to the robotic coordinate system in order to properly manipulate the robotic arm 40.

[0067] Elements of the system 20 including the radiator 26 may be controlled by a processing circuit 38, which includes a processing unit in communication with one or more memories. Typically, the elements may be connected to the processing circuit 38 via a cable, for example, the radiator 26 may be connected to the processing circuit 38 via a cable 58. Alternatively or in addition, the elements may be coupled to the processing circuit 38 wirelessly. The processing circuit 38 may be mounted in a console 50, which includes an operating control 51, which typically includes a keypad and / or a pointing device such as a mouse or trackball. The console 50 is also connected to other elements of the medical surgical system 20, such as the proximal end 52 of the medical instrument 28. The doctor 54 interacts with the processing circuit 38 using the operating control 51 while performing the surgery, and the processing circuit 38 may present the results generated by the system 20 on a display screen 56.

[0068] In some embodiments, prior to performing a medical procedure, a CT image of patient 22 is acquired. The CT image is stored in a memory (not shown) for subsequent retrieval by processing circuitry 38. Figure 1 , the display screen 56 displays various views 59 of a previous CT scan (or other suitable scan) that can assist the physician 54 in guiding the medical instrument 28 in the body part. The display screen 56 also shows an image 61 captured by a camera (not shown) of the medical instrument 28. The CT image can be registered with the magnetic coordinate system so that a representation of the medical instrument 28 can be displayed on the display screen 56 along with the CT image.

[0069] In implementation, some or all of these functions of processing circuit 38 may be combined in a single physical component, or alternatively, implemented using multiple physical components. These physical components may include hard-wired or programmable devices, or a combination of the two. In some embodiments, at least some of the functions of the processing circuit may be implemented by a programmable processor under the control of suitable software. The software may be downloaded to the device in electronic form via a network, for example. Alternatively or in addition thereto, the software may be stored in a tangible, non-transient computer-readable storage medium, such as an optical, magnetic or electronic memory.

[0070] The system 20 may also include an irrigation pump 64 disposed in the console 50. Figures 3 to 6 The flush pump 64 is described in greater detail.

[0071] Reference now Figures 3 to 6 . Figure 3 is a schematic diagram of a medical device 28 according to an embodiment of the present invention. Figures 4 to 6 for Figure 3 Various illustrations of the distal end 34 of the medical device 28 are shown.

[0072] The medical device 28 includes a grasper head 68 having complementary grippers 66 (labeled 66-1 and 66-2, respectively, in the drawings) and conductive surfaces 70 (labeled 70-1 and 70-2, respectively) disposed on respective distal portions of the grippers 66, with the conductive surface 70-1 disposed on the gripper 66-1 and the conductive surface 70-2 disposed on the gripper 66-2. The grippers 66 may optionally include one or more cutting edges (not shown). The conductive surface 70 may be formed of any suitable conductive material, such as, but not limited to, platinum iridium. The cutting edges may be formed of any suitable material, such as, but not limited to, stainless steel. The dimensions of the grasper head 68 are on the order of millimeters.

[0073] The conductive surface 70 provides an area on the gripper 66 through which an electrical current is applied to the grasped tissue. The conductive surfaces 70 are electrically isolated from each other in the grasper head 68. Such electrical isolation can be achieved by forming at least a portion of the grasper head 68 or at least a portion of the gripper 66 from an insulating material, such as a biocompatible plastic. In some embodiments, the grasper head 68 and / or the gripper 66 can be formed of a conductive material, such as a biocompatible plastic, coated with an insulating material.

[0074] In some embodiments, the grasper head 68 includes two elongated members 72, wherein each elongated member 72 includes a gripper 66. The grasper head 68 also includes a pin 74 connecting the two elongated members 72 to allow angular movement between the gripper 66-1 and the gripper 66-2. The elongated members 72 can be at least partially formed of an insulating material so that the conductive surfaces 70 disposed on the grippers 66 are electrically insulated from each other.

[0075] Medical device 28 also includes an actuator 76 configured to close gripper 66 so as to bring conductive surface 70-1 and conductive surface 70-2 into contact with tissue of a body part of a living subject. Figure 3 , the actuator 76 is shown as including a pull handle 78 with an electrical wire 80 connected to the proximal end of one of the elongated members 72 of the grasper head 68, such that pulling the pull handle 78 closes the grippers 66 together. The actuator 76 may include any suitable manual element (e.g., but not limited to, a handle with a scissor action connected to the grasper head 68 with an electrical wire or rod) and / or automatic element (e.g., but not limited to, using one or more motors and gears to control the opening and closing of the grippers 66).

[0076] The grasper head 68 includes at least one position tracking transducer 32 configured to provide a position signal indicative of the position of the grasper head 68. In some embodiments, the grasper head 68 includes two position tracking transducers 32, one in each elongated member 72. The position tracking transducers 32 are connected to the processing circuit 38 via wires 88. The provision of one position tracking transducer 32 in each elongated member 72 provides position data regarding the position of each elongated member 72 and each gripper 66. The processing circuit 38 is configured to calculate the position of the grasper head 68 in response to the position signal. Each position tracking transducer 32 may include 2 or 3 orthogonally placed coils or appropriately placed electrodes. Based on the calculated position, a representation of the medical device 28 including the grasper head 68 in the body part may be presented to the display 56. The physician 54 may then guide the grasper head 68 within the body part based on the presented representation of the medical device 28 including the grasper head 68.

[0077] The grasper head 68 includes a proximity sensor 82 that is configured to output one or more proximity signals in response to displacement between the gripper 66 - 1 and the gripper 66 - 2 .

[0078] In some embodiments, the proximity sensor 82 includes two electrical contacts 84 disposed on two opposite sides of the two elongated members 72 on the grasper head 68. The electrical contacts 84 are connected to the processing circuit 38 via wires 88. The electrical contacts 84 are configured to contact each other when the displacement between the gripper 66-1 and the gripper 66-2 is less than a given threshold displacement. When mutual contact is made, the circuit is completed, resulting in a signal (i.e., a proximity signal) being sensed by the processing circuit 38. The displacement can be measured as a distance or an angular displacement. The corresponding electrical contacts 84 are connected to the elongated members 72 of the grasper head 68 via corresponding springs 86. The springs 86 allow the gripper 66 to close even beyond a given threshold displacement and provide a restoring force to open the gripper 66 when the actuator 76 releases the closure of the gripper 66.

[0079] In some embodiments, the proximity sensor 82 includes two position tracking transducers 32 disposed in the grasper head 68. The position tracking transducers 32 of the proximity sensor 82 are configured to provide proximity signals corresponding to respective position signals indicative of respective positions of the grippers 66-1 and 66-2.

[0080] The processing circuit 38 is coupled to sense the displacement between the gripper 66 - 1 and the gripper 66 - 2 in response to the proximity signal.

[0081] In embodiments where the proximity sensor 82 includes electrical contacts 84 , the sensing of displacement by the processing circuit 38 is based on two electrical contacts 84 contacting one another, thereby completing an electrical circuit resulting in a proximity signal flowing in the processing circuit 38 .

[0082] In embodiments where the proximity sensor 82 includes the position tracking transducer 32, the processing circuit 38 senses the displacement by calculating the displacement between the grippers in response to a proximity signal (e.g., a position signal) provided by the position tracking transducer 32. The processing circuit 38 is configured to calculate the displacement between the gripper 66-1 and the gripper 66-2 in response to the corresponding position signal. The displacement may be measured as a distance or an angular displacement.

[0083] The processing circuit 38 is configured to apply a current between the conductive surface 70-1 and the conductive surface 70-2 of the gripper 66 when the sensed displacement is less than a given threshold displacement. As a result of the two electrical contacts 84 contacting each other, the processing circuit 38 can apply a current between the conductive surfaces 70, thereby closing the circuit and causing the current to flow. Alternatively, the processing circuit 38 can apply the current in response to the calculated displacement being less than a given threshold displacement. The current can be any suitable current, such as, but not limited to, a direct current (DC) or a current close to DC (e.g., a low frequency alternating current, such as up to 20 KHz). The power output used during coagulation can be any suitable value, such as, but not limited to, on the order of hundreds of watts.

[0084] The medical device 28 includes an irrigation tube 90 disposed therein and connected to an irrigation pump 64. The irrigation pump 64 is configured to pump fluid into the irrigation tube 90 to cool the tissue. The irrigation pump 64 may be activated in response to the current flowing between the conductive surfaces 70.

[0085] Reference now Figure 7 , which is a schematic diagram of a grasper head 68B according to a first alternative embodiment of the present invention. The grasper head 68B is substantially similar to the grasper head 68B except that the position tracking transducer 32 is disposed at a distal portion of the grasper head 68B adjacent to the conductive surface 70 of the gripper 66. Figures 3 to 6 The grasper head 68 is the same.

[0086] Reference now Figure 8 , which is a schematic diagram of a gripper head 68C according to a second alternative embodiment of the present invention. The gripper head 68C is substantially the same as the gripper head 68C except that the gripper head 68C does not include an electrical contact 84 or a spring 86. Figure 3-6 The same as the grasper head 68. Figure 8 In the embodiment of the present invention, the displacement of the gripper 66 is calculated based on the position signal provided by the position tracking transducer 32.

[0087] Reference now Fig. 9 , which includes Figure 1 Flowchart 92 of exemplary steps in a method of operating the system 20. Figure 3 It should be noted that the order of the steps given below is exemplary, and the steps may be performed in any suitable order. In some embodiments, not all of the steps described below are performed. In some embodiments, one or more steps may be replaced by any suitable one or more steps.

[0088] Actuator 76 is configured to close (block 94) gripper 66 so as to bring conductive surfaces 70-1, 70-2 into contact with tissue of a body part of a living subject.

[0089] The proximity sensor 82 is configured to output (block 96 ) at least one proximity signal in response to the displacement between the grippers 66 .

[0090] When the proximity sensor 82 includes two electrical contacts 84 disposed on the elongated member 72 of the grasper head 68, the electrical contacts 84 are configured to contact each other when the displacement between the grippers 66 is less than a given threshold displacement. When the electrical contacts 84 contact each other, the circuit is completed, resulting in a signal (i.e., a proximity signal) being sensed by the processing circuit 38.

[0091] When the proximity sensor 82 includes a position tracking transducer 32 disposed in the elongated member 72 of the grasper head 68 , the proximity signal corresponds to the position signal provided by the position tracking transducer 32 .

[0092] The processing circuit 38 is coupled to sense (block 98 ) the displacement between the grippers 66 in response to the proximity signal.

[0093] As previously described, when the proximity sensor 82 includes two electrical contacts 84 , when the electrical contacts 84 contact each other, the circuit is completed, resulting in a signal (ie, a proximity signal) being sensed by the processing circuit 38 .

[0094] When the proximity sensor 82 includes a position tracking transducer 32, the displacement between the grippers 66 is sensed by the processing circuit 38, which performs calculations based on the provided position signals, as will be described in more detail below. The processing circuit 38 is configured to calculate the displacement between the grippers 66 in response to the corresponding position signals.

[0095] The processing circuit 38 is configured to apply a current between the conductive surfaces 70 of the gripper 66 when the sensed displacement is less than a given threshold displacement (block 100 ).

[0096] For the sake of clarity, various features of the present invention described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, for the sake of simplicity, various features of the present invention are described in the context of a single embodiment and may also be provided separately or in any suitable sub-combination.

[0097] The above embodiments are cited by way of example, and the present invention is not limited by what is specifically shown and described above. On the contrary, the scope of the present invention includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which should occur to those skilled in the art when reading the above description, and which are not disclosed in the prior art.

Claims

1. A medical system comprising: Medical devices, including: a grasper head comprising: complementary first and second grippers; and first and second conductive surfaces disposed on respective distal portions of the first and second grippers, the first and second conductive surfaces being electrically insulated from each other in the grasper head; an actuator configured to close the gripper to bring the first and second conductive surfaces into contact with tissue of a body part of a living subject; and a proximity sensor configured to output at least one proximity signal in response to a displacement between the first gripper and the second gripper; and processing circuitry coupled to sense a displacement between the first gripper and the second gripper in response to the at least one proximity signal and to apply a current between the first conductive surface and the second conductive surface of the gripper when the sensed displacement is less than a given threshold displacement; wherein the proximity sensor comprises two electrical contacts disposed on the grasper head and electrically connected to the processing circuit and configured to contact each other when the displacement between the first gripper and the second gripper is less than the given threshold displacement; wherein respective said electrical contacts are connected to said grasper head via respective springs; and Wherein when the two electrical contacts are in contact with each other, the processing circuit is completed.

2. The system of claim 1 , wherein the grasper head comprises at least one position tracking transducer configured to provide a position signal indicative of the position of the grasper head, and the processing circuit is configured to calculate the position of the grasper head in response to the position signal.

3. The system of claim 1 , wherein the proximity sensor comprises two position tracking transducers disposed in the grasper head and configured to provide respective position signals included in the at least one proximity signal indicating respective positions of the first gripper and the second gripper, and the processing circuit is configured to calculate the displacement between the first gripper and the second gripper in response to the respective position signals.

4. The system of claim 1, further comprising an irrigation pump, wherein the medical device comprises an irrigation tube coupled to the irrigation pump, the irrigation pump being configured to pump fluid into the irrigation tube to cool the tissue.

5. The system of claim 1, wherein the grasper head comprises: two elongated members, the two elongated members comprising the first gripper and the second gripper; and a pin connecting the two elongated members to allow angular movement between the first gripper and the second gripper.

6. The system of claim 5, wherein the proximity sensor comprises two electrical contacts disposed on two opposite sides of the two elongated members and configured to contact each other when the displacement between the first gripper and the second gripper is less than the given threshold displacement.

7. The system of claim 6, wherein respective ones of the electrical contacts are connected to the elongated member via respective springs.

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