Abstract:
A scanning cannula for scanning an electrosurgical instrument for electrical insulation defects includes an elongated sleeve having a receiving end, an opposite exit end, and a passageway extending from the receiving end to the exit end. At least one sweeping contact is disposed in the passageway with a limit switch or photocell upstream. A circuit is electrically connected to the at least one sweeping contact. A communication device is connected to the circuit to transmit signals from the circuit to a controller of a surgical instrument. An electrosurgical instrument inserted into the receiving end of the sleeve passes through the at least one sweeping contact, and any electrical defect of the electrosurgical instrument detected by the at least one sweeping contact and assessed by the software is relayed as an error signal to the circuit, which communicates the error signal to the controller. The controller cuts current to the electrosurgical instrument and signals an alarm. 
     A minimally invasive RF scanning cannula is used for access in minimally invasive surgery (MIS). The cannula is partially inserted into the abdominal wall following a puncture wound that is performed by the trocar which protrudes from the bottom end of cannula. Once placed into the patient&#39;s skin and related tissue, the cannula allows insertion of the working shafts of surgical devices into the laparoscopic cavity while sealing insufflation pressure. Many of the devices that are used in MIS are instruments that deliver monopolar RF energy to the target tissue for the purpose of cauterizing, cutting and sealing. RF monopolar energy is very powerful and many unintended injuries occur due to arcing and stray currents through insulation defects. The present invention discloses a cannula with an added capability for testing the insulated shafts of any incoming devices for insulation defects, and not allow electricity to flow to the device from the generator unless the insulation of the shaft has been tested and found to be free of defects (or when the OVERRIDE function is activated). 
     Like conventional cannulas, the scanning cannula has an elongated sleeve with a receiving end, an opposite exit end, and a passageway extending from the receiving end to the exit end. Two sweeping contacts or rings (or a single sweeping contact as in other embodiments) and one micro-switch or sensor are present in the passageway near the receiving end and transmit scanning information to the controller. The controller safely isolates the patient from any electrical risks during testing via the use of high-voltage relays. A high-voltage power supply contained within the controller mimics the typical maximum electrical strain placed on the device during surgery to make the test independent of generator settings. In the event of a defect being discovered, an alarm is sounded and a message displayed on the LCD display of the controller. In the event of a successful test or the enabling of a user override, electrosurgery may proceed as with a conventional cannula. 
     The invention further includes the use of an attachable scanning chamber to commercially available non-scanning cannulas, thus allowing virtually all users of endoscopic cannulas to add vital safety feature: RF insulation scan as last step before the incoming RF electrosurgical instrument is used on the patient.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 13/127,577, filed on May 4, 2011, based on PCT Application Ser. No. PCT/US2009/064185, filed Nov. 12, 2009, which claims priority to U.S. Provisional Application Ser. No. 61/116,395, filed on Nov. 20, 2008. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention relates to electrosurgery, and more particularly to cannulas for use in electrosurgery. 
       BACKGROUND 
       [0003]    Electrosurgery (ES) and specifically endoscopic ES (EES) are fast growing technologies that expanded a surgeon&#39;s capabilities to cut, coagulate, and cauterize tissue and vessels with unprecedented efficiency. 
         [0004]    However, ES involves the application of high voltage to the working elements of ES devices such as monopolar hand instruments. Thus, the danger of undesired electrocution and even severe burns always exists and great efforts have been devoted towards implementing durable insulation and protective means, to protect both the surgeon and the patient. 
       SUMMARY 
       [0005]    The present invention provides a scanning cannula for the detection of defects in the electrical insulation of endoscopic ES devices. The scanning cannula has scanning capabilities for detecting arcing and leakage currents through the ES device when the ES device is inserted through the cannula. The present invention thereby adds an active safety measure to electrosurgery, specifically the checking of all devices upon insertion through the scanning cannula. 
         [0006]    Further, the present invention provides the means to scan all sterile RF surgical devices upon entry into the endoscopic cannula when it is attached to the patients body, without jeopardizing the devices&#39; sterility, as the scanning cannula is sterile and preferably disposable. Until now, such scanning was not feasible as arcing detection devices are not sterile and require post sterilization to the scanning. It is well known in the MIS industry that defects to insulation can and do occur during the sterilization process in many cases. The current invention provides scanning as last step prior to entry into the body&#39;s cavity. 
         [0007]    The present invention provides a scanning cannula or an attachable scanning chamber device for the detection of defects in the electrical insulation of endoscopic ES devices. In the case of the attachable scanning chamber version, the device may be attached to commercially available inert (i.e., non-scanning) cannulas. The scanning cannula has scanning capabilities for detecting arcing and leakage currents through the ES device when the ES device is inserted through the cannula. The present invention thereby adds an active safety measure to electrosurgery, specifically the checking of all devices to be used on the patient upon insertion through the scanning cannula. 
         [0008]    In one embodiment, the present invention provides a stand-alone scanning cannula that scans mostly tubular insulated elements, typically the working shafts of RF electrosurgical monopolar and hybrid instruments (i.e., RF devices capable of mono-bipolar energy modes), for insulation imperfections and leakage current by communicating via wires or wirelessly with a wired or wirelessly controlled controller or an RF generator having added circuitry necessary to eliminate the controller. 
         [0009]    The scanning cannula works with an accompanying controller which includes control and user interface circuits and/or software. The scanning cannula further includes control mechanisms related to the scan cycle. The scanning cannula also may have illumination and insufflation pressure monitoring and even regulating capabilities, thus making it far more valuable than an inert cannula. 
         [0010]    A scanning cannula in accordance with the present invention that scans the shafts of electrosurgical instruments for electrical insulation defects includes an elongated sleeve having a receiving end, an opposite exit end directly into the cannula, and a passageway extending from the receiving end to the exit end directly into the cannula. At least one sweeping contact is disposed in the passageway. A communication device is connected to the circuit to transmit signals from the circuit to a controller of a surgical instrument. An electrosurgical instrument inserted into the receiving end of the sleeve passes through the at least one sweeping contact, and any electrical defect of the electrosurgical instrument detected by the at least one sweeping contact is relayed as an error signal to the circuit, which communicates the error signal to the controller. A record of scanning tests and the date and time of each test, whether passed or failed, may also be stored in the controller for future reference. 
         [0011]    In one embodiment, each sweeping contact may be a disk-shaped ring including a plurality of fingers extending towards a hollow center of the ring or fingers that extend down from a hollow center in one direction or the other. Other embodiments have additional options for configurations of sweeping contacts, or even just one sweeping contact. The scanning cannula may include a pair of sweeping contacts spatially disposed from each other in the passageway. The communication device may include an antenna that wirelessly transmits signals to the controller. Alternatively, the communication device may include a cable that electrically transmits signals to the controller. The circuit may include a battery that powers the scanning cannula. The circuit may include a capacitor electrically connected to each of the at least one sweeping contact. The circuit may include one or more LEDs that display status information. Preferably, however, all circuits would primarily reside in the controller and receive inputs from the scanning cannula. 
         [0012]    The scanning cannula may include a photo cell or micro-switch disposed in the passageway upstream of the at least one sweeping contact. The photo cell or micro-switch may be electrically connected to the circuit, and the photo cell or micro-switch may detect the presence of an electrosurgical instrument in the passageway. The scanning cannula may include a light source in communication with an optical fiber disposed along a length of the sleeve to illuminate the sleeve and the internal surroundings. The scanning cannula may include a pressure sensor electrically connected to the circuit, and a conduit in fluid communication with the pressure sensor for dynamic monitoring of insufflation pressure. 
         [0013]    A method of scanning an electrosurgical instrument for electrical defects in accordance with the present invention includes the steps of providing an elongated device which is configured to be disposed in a patient, which has a receiving end, an opposite exit end, and a passageway extending from the receiving end to the exit end; disposing at least one sweeping contact in the passageway; having a circuit in the device; electrically connecting at least one sweeping contact in the device a circuit; connecting a communication device to the circuit to transmit signals from the circuit to a controller of a surgical instrument; inserting an electrosurgical instrument into the receiving end of the sleeve; passing the electrosurgical instrument through the at least one sweeping contact, whereby any electrical defect of the electrosurgical instrument detected by the at least one sweeping contact is relayed as an error signal to the circuit; and communicating the error signal to the controller. 
         [0014]    An electrosurgical system in accordance with the present invention for scanning an electrosurgical instrument for electrical defects includes a scanning cannula including: an elongated sleeve having a receiving end, an opposite exit end, and a passageway extending from the receiving end to the exit end; at least one sweeping contact disposed in the passageway; a circuit mounted in the sleeve, the at least one sweeping contact being electrically connected to the circuit; and a communication device (wired or wireless) connected to the circuit to transmit signals from the circuit. A controller is in communication with the scanning cannula. An electrosurgical generator is electrically connected to the controller. An electrosurgical instrument is electrically connected to the controller. The electrosurgical instrument is inserted into the receiving end of the sleeve and passes through the at least one sweeping contact. Any electrical insulation defect of the electrosurgical instrument detected by the at least one sweeping contact is relayed as an error signal to the circuit, which communicates the error signal to the controller. Records of scanning tests and the date and time of these tests, whether passed or failed, may be stored in the controller for future reference. 
         [0015]    Optionally, the communication device may include an antenna, and the circuit may wirelessly communicate with the controller via the antenna. Alternatively, the communication device may include a cable that is electrically connected to the circuit and the controller, and the circuit may communicate with the controller through the cable. Upon receiving an error signal from the scanning cannula, the controller may warn the user by displaying a warning message and/or sounding an alarm tone. The electrosurgical device is disconnected from the electrosurgical generator during testing and is only reconnected if the test is successful or an override command (pressing the override button) is provided. 
         [0016]    The present invention provides a scanning cannula and controller for automatic scanning of mostly tubular endoscopic electrosurgical devices. This scanning cannula has capabilities for detecting arcing and leakage currents from the electrosurgical device when said device&#39;s shaft is inserted through the cannula into the endoscopic surgical site. An active safety measure is added to ES, specifically the checking of all devices upon insertion through the scanning cannula while the scanning cannula is already disposed in the patient&#39;s body as the access port to the laparoscopic cavity. The system is set up to only allow surgery to proceed if the instrument has been proven free of defects, or if the surgeon elects to override the safety features of the cannula. 
         [0017]    The scanning cannula is connected to an electrosurgical generator via a controller which houses a microprocessor that provides logical control of the scanning process. The controller also contains a high voltage power supply with voltage in excess of that typically selected for ES, thereby eliminating the need for the surgeon to alter the generator settings during testing. The controller also contains high voltage relays that electrically isolate the instrument and the ground pad from the generator unless the test has been passed or the override has been activated. During the test, the instrument is disconnected from the generator to fully isolate the patient from any stray arcing or leakage current. Optionally, the ground pad may also be electrically disconnected from the generator during the scanning process, thereby further isolating the patient from the generator. Once an instrument has successfully passed the test for insulation defects, both the instrument and the ground pad are reconnected to the generator so that surgery may proceed. 
         [0018]    In an alternative embodiment, the ground pad is not disconnected during testing, and is not connected to the controller, but instead is connected directly to the generator. In this alternative embodiment then only the instrument would need to be reconnected to the generator in that embodiment so that surgery may proceed. 
         [0019]    Scanning of the instrument is performed by two or more sensors contained within the cannula:
       A micro switch or photo-cell to determine the presence of an instrument within the cannula.   A high-voltage sweeping contact to scan for insulation defects.
 
A low voltage sweeping contact may also be used in some embodiments to determine the position of the instrument in the cannula. Specifically, the low voltage contact may be used to sense whether the exposed tip region or the insulated shaft of the instrument are currently being scanned by the high voltage contact.
       
 
         [0022]    Outputs from these instruments are used by the microprocessor in the controller to determine whether the instrument has passed testing. The controller is fitted with an LCD screen (or a different display) and audio sounds to inform and alert the user of the results of the scanning test. 
         [0023]    These and other features and advantages of the invention will be more fully understood from the following detailed description of the invention taken together with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    In the drawings: 
           [0025]      FIG. 1  is an environmental view of a wireless scanning cannula in accordance with the invention having an electrosurgical instrument inserted therein; 
           [0026]      FIG. 2  is an enlarged view of a portion of the wireless scanning cannula; 
           [0027]      FIG. 3  is an environmental view of the wireless scanning cannula and its related circuit in scanning mode; 
           [0028]      FIG. 4  is a partial view of an alternative embodiment of a scanning cannula in accordance with the invention; 
           [0029]      FIG. 5  is a partial view of another alternative embodiment of a scanning cannula in accordance with the invention; 
           [0030]      FIG. 6  is an environmental view of yet another alternative embodiment of a scanning cannula in accordance with the invention as a wired embodiment; 
           [0031]      FIG. 7  shows a typical setup for MIS (Minimally Invasive Surgery) with a wired scanning cannula, controller, generator, patient (a portion in cross-section), ground pad, and wiring; 
           [0032]      FIG. 7A  shows a wired scanning cannula that can be used with the setup of  FIG. 7 ; 
           [0033]      FIG. 8  shows a view of the scanning cannula with advanced sweeping contacts and a cross section through the scanning portion; 
           [0034]      FIG. 8A  is an enlarged sectional view of the head portion of the scanning cannula with a monopolar instrument partially inserted; 
           [0035]      FIG. 9  shows a typical monopolar instrument entering the scanning cannula; 
           [0036]      FIG. 10  shows an elevational view of the scanning cannula and trocar and  FIG. 10A  is an enlarged section through the scanning cannula head and the attached trocar; 
           [0037]      FIG. 11  shows a sectional perspective view of the cannula head; 
           [0038]      FIG. 11A  illustrates a exploded elevational view of a conventional trocar that may be used with the cannula device; 
           [0039]      FIG. 11B  shows an exploded elevational view of the scanning cannula; 
           [0040]      FIGS. 12 ,  12 A,  12 B,  12 C,  12 D,  12 E and  12 F show details of the sweeping contacts, the micro switch, and a micro switch and contact board assembly; 
           [0041]      FIG. 13  shows a typical application of an attachable/detachable scanning head with dual sweeping contacts to be attached to a conventional cannula; 
           [0042]      FIG. 13A  shows the cable secured to the scanning head that attaches the scanning head to a controller; 
           [0043]      FIGS. 13B and 13C  show an elevated perspective view of the scanning head of  FIG. 13  detached from the adjacent cannula and a cross-section of the scanning head of  FIGS. 13 ,  13 A and  13 B attached to the cannula; 
           [0044]      FIG. 14  shows the flow chart for the controller to control at least one scanning cannula having two sweeping contacts; 
           [0045]      FIGS. 15 and 16  illustrate the control circuit for a controller to control at least one scanning cannula having two sweeping contacts and an LED and/or audio component for communications with the user; 
           [0046]      FIG. 17  shows a cross-section of an alternative embodiment of a scanning cannula with a single sweeping contact; 
           [0047]      FIGS. 18A ,  18 B,  18 C and  18 D show an attachable scanning head with a single sweeping contact (and the attachment clip shown separately at  FIG. 18D ) to be attached to commercially available cannulas; 
           [0048]      FIG. 19  shows the application of multiple scanning cannulas in the operation on one patient; 
           [0049]      FIG. 19A  illustrates an attachment device for implementing multiple scanning cannulas in the operation of one patient; 
           [0050]      FIGS. 20 ,  20 A and  20 B illustrate user interfaces for communication with the user as well as the hand operated override control on the scanning cannula; and 
           [0051]      FIG. 21  depicts a flow chart of the functionality of software that can be used with the scanning cannula  205  having one sweeping contact  155 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0052]    Referring now to the drawings in detail, numeral  10  generally indicates a scanning cannula in accordance with the invention. The scanning cannula  10  provides for scanning of an electrosurgical instrument and detection of defects in the electrical insulation of the instrument, which increases the safety of the instrument and related electrosurgical procedures. 
         [0053]    As illustrated in  FIGS. 1 through 3 , an endoscopic, monopolar (RF) surgical device  12  such as an electrosurgical instrument having an insulated shaft  14  is partially inserted into the scanning cannula  10 . The insulated shaft  14  of the surgical device  12  is scanned for insulation defects by the scanning cannula  10  as described herein. 
         [0054]    The scanning cannula  10  includes an elongated sleeve  16  having an instrument receiving end  18 , an opposite exit end  20 , and a passageway  22  extending from the receiving end to the exit end. A portion of the passageway  22  adjacent the receiving end  18  defines a scanning chamber  24 . Two sweeping contacts  26 ,  28  are disposed in the scanning chamber  24  and are spaced apart at a safe distance to avoid arcing between them (e.g., between 1 mm and 8 mm). Each sweeping contact  26 ,  28  may be a disk-shaped ring  30  including a plurality of fingers  32  extending towards a hollow center of the ring. A circuit such as a printed circuit board (PCB)  36  or similar circuit arrangement is mounted in or on or integral with the sleeve  16 . The sweeping contacts  26 ,  28  are each separately wired to a capacitor  34  included in the PCB  36 . The PCB  36  includes a battery  38 , the two capacitors  34  each electrically connected to a separate sweeping contact  26 ,  28 , a voltage buildup mechanism  40  between the battery  38  and capacitors  34 , a control mechanism (activation button  42  such as an on/off switch or similar), two LEDs  44 ,  46  (although more than two LEDs may be included), and a communication device  48  to transmit signals from the PCB  36 . In one embodiment, the communication device  48  may include an antenna that wirelessly transmits necessary signals from the PCB  36  to a wireless controller  50  that is electrically connected to the surgical device  12 . 
         [0055]      FIG. 1  illustrates “normal” wiring for the wireless version of the scanning cannula as to be used in surgery. The wirelessly controlled controller  50  is connected to monopolar and ground ports on an electrosurgical generator  52  via cables  54 ,  56 . The surgical device  12  is wired to the monopolar port on the controller  50  via a power plug  58  and cable  60 . A ground pad  62 , which is attached to a patient, is connected as shown to the controller  50  ground via a cable  64 , but may also alternatively be connected directly to the generator&#39;s ground. 
         [0056]      FIG. 2  illustrates a typical situation pertaining to a scanning function of the scanning cannula  10 . In a scanning mode, activation button  42  is depressed (switched to the on position), and the battery  38  charges the capacitors  34  and sweeping contacts  26 ,  28  with high voltage. At the same time, antenna  48  transmits a signal to the controller  50  to switch the circuits as shown in  FIG. 3 . 
         [0057]    When the capacitors  34  are charged, blue LED  46  indicates that the scanning cannula  10  is ready for a scanning procedure. 
         [0058]    A practitioner such as a surgeon or other health care provider inserts the shaft  14  of the surgical device  12  into the scanning chamber  24  through the receiving end  18  of sleeve  16 . The scanning then proceeds as follows. Exposed jaw assembly  66 , at a distal end of the insulated shaft  14 , is inserted through a tubular inlet (at receiving end  18 ) of the scanning chamber  24  and moved through the charged sweeping contacts  26 ,  28 . The initial passage of the exposed jaw assembly portion  66  is detected by arcing or conduction from sweeping contacts  26  and  28  onto the exposed jaw portion  66 . The arcing may be limited by a resistive circuit designed to reduce current flow upon arcing. The upper contact is typically set to 3000V or more and the lower contact is set to a low voltage such as 5V. Once the lower sweeping contact has returned to its lower setting (5V) and is no longer detecting the exposed metallic tip of the instrument, the scanning of the shaft begins. Any further arcing from sweeping contact  26  is identified as a defect in insulation. The signal leads to a warning on either or both of the scanning cannula  10  and the controller  50 , and eventually to the cutting of power from the generator  52  to the surgical device  12  upon completion of the scanning. The scan itself, if executed automatically, is limited in time to approximately 5 seconds, as an example. After the scan, if no arcing was detected during the scan period, an OK signal appears on both the scanning cannula  10  and the controller  50 . In one embodiment, the scan duration and scan initiation may be controlled manually by switching the controller  50  to scan mode and switching the controller  50  back to normal work mode once the surgical device  12  has been inserted and no alarm was displayed. 
         [0059]      FIG. 4  illustrates another embodiment of detection at the beginning of the scanning procedure. In this embodiment, the scanning cannula  110  includes one sweeping contact  126 . A photo or light cell  170  is disposed below (downstream of) the single sweeping contact  126  in the scanning chamber  124 . The photo cell  170  is electrically connected to the PCB  136 . The photo cell  170  may detect the presence of the dark insulating sheath  172  of the shaft  114 , indicating the PCB that the surgical device  112  is present in the scanning chamber  124 . Any further arcing from the single sweeping contact  126  is then processed by the PCB  136  as evidence of an insulation defect. 
         [0060]    In yet another embodiment illustrated in  FIG. 5 , the scanning cannula  210  may optionally include a light source  274  such as a bulb or similar that emits light which is then transmitted via optical fibers  276  or other transmission means such as a built-in light conduit or similar. Light from the light source  274  glows through the distal tubular exit end  220  of the scanning cannula  210 , to aid in illumination when needed and traceability during the penetration stage. The scanning cannula  210  may also include dynamic pressure monitoring of insufflation pressure. A pressure sensor  278  may read cannula/insufflation pressure via conduit  280 . The scanning cannula may even control an insufflator (not shown) remotely. The light source  274  and pressure sensor  278  may each be electrically connected to the PCB  236 . 
         [0061]    In an alternative embodiment shown in  FIG. 6 , the scanning cannula  310  may be arranged in wired form, i.e., using a powered, multi-channel cable from the controller  350  into the scanning cannula  310  and eliminating the battery and capacitors in the PCB. An example is illustrated in  FIG. 6 , in which powered cable  382 , branched from cable  360 , is connected with the scanning cannula  310  circuitry via power plug  384  and wires  386 . The cable  382  could, alternatively, be attached directly to the controller  350 . Wireless communication is therefore not required as the physical connection (i.e., cable) with the controller  350 , directly or through branching, may be used to convey information such as test mode beginning, test mode end, and scanning results. A decision to cut off power to the electrosurgical generator  352  may be made in the controller  350  or the generator  140 , if equipped properly. Optionally, another ground reference may be achieved by having the controller  350  include an attached ground wire  368 , thus avoiding the use of patient capacitance as the ground reference. 
         [0062]    The description herein will demonstrate the details of the invention. The invention provides a means to scan for insulation defects of incoming devices into the scanning cannula and disconnect the RF power source (i.e. the generator) from a defective device and thus eliminating potential injuries to patients and users. 
         [0063]      FIG. 7  shows a typical setup for minimally invasive surgery, involving the scanning cannula and the controller. The patient  101  is on the operating table similar to  FIG. 1  (patient shown here in partial section), is anesthetized and is connected to a ground pad  2  connected to the controller  103  via cable  4  (not shown) also as similar to  FIG. 1 . Ground pad  2  may be connected directly into the generator  140  ground as an alternative. A scanning cannula  105  is affixed to the patient&#39;s abdominal wall and is wired to the controller via cable  106 . In a case where a plurality of scanning cannulas are being used, the cable  106  may be connected first into a multiple connector  126  that connects into the controller  103  via cable  127 . 
         [0064]    An insulated monopolar surgical instrument  107  is inserted into the laparoscopic cavity  101   a  via scanning cannula  105 . The instrument  107  is hooked to the controller  103  via its power plug  108  and cable  109 . The controller  103  is hooked to the generator (ESU)  140  via cable  111 . The controller is connected to a standard wall socket via cable  142   a . The ESU is connected to a standard wall socket via cable  142   b . Also included in  FIG. 7  is a second scanning cannula  141  which is inserted into the body of the same patient (human, animal, etc.). Scanning cannula  141  can operate the same as scanning cannula  105  or can be wirelessly connected to a controller as illustrated above in  FIGS. 2 through 6 . The scanning cannula is also illustrated separately in  FIG. 7A . 
         [0065]      FIGS. 8 and 9  show a typical view of a scanning cannula  105  schematically inserted in the patient and, at  FIG. 8A , a partially inserted monopolar instrument shaft  127  just prior to insertion into the abdominal wall.  FIG. 8A  is a cross section through the upper portion of scanning cannula  105 . We will focus on the scanning features of the scanning cannula and describe the general features of the monopolar instrument  107  and the cannula portion  123  of the scanning cannula  105  for clarification only. 
         [0066]    The monopolar instrument shaft  127  is inserted into the scanning cannula  105 . The instrument clevis  146  is rigidly attached to the monopolar instrument shaft  127  and pivotally to the monopolar instrument jaws  144 . The monopolar instrument shaft  127  passes through the scanning cannula  105  at cover  117  via tapered inlet  118  where it trips limit switch  125 , and then through upper sweeping contact (USC)  119  and lower sweeping contact (LSC)  120 . The monopolar instrument shaft  127  extends through radial seal  121  and through duckbill seal  122  to enter the scanning cannula hollow shaft  123  at its interior  123   a . The monopolar instrument shaft  127  is made long enough so it protrudes through the hollow shaft  125  enough to expose its clevis  146  and jaws  144 . 
         [0067]      FIG. 9  shows a typical monopolar surgical instrument  107  inserted into a scanning cannula  105  via inlet  118 . Upon entering the scanning cannula  105 , the exposed jaws first touch (and trip) the micro-switch  125 , then touch the USC  119 , and lastly touch the LSC  120  (see  FIG. 11 ). These occurrences are communicated to and noted by circuitry in the controller and are followed by the scanning of the insulated portion  131  of the shaft  127 . The shaft  127  of the instrument  107  has an insulated portion  131  (see  FIGS. 8 and 8A ) that will be fed through the hollow shaft  123  until reaching the bottom of the abdominal cavity and scanned at the same time by the USC  119  and LSC  120  as per the steps below: 
       Preparation Stage 
       [0068]    With reference to  FIG. 9 : 
         [0069]    Patient on operating table, anesthetized with ground pad attached. 
         [0070]    Controller (CB)  103  is attached to wall socket  480  via cable  112   a . CB  103  is ON. 
         [0071]    Patient insufflated and the scanning cannula  105  together with the trocar  145  ( FIG. 10 ) is disposed into patient&#39;s abdominal wall. 
         [0072]    Trocar  145  ( FIGS. 10 and 11A ) is removed 
         [0073]    Electrosurgical generator (ESU)  140  is ON. Surgeon selects desired settings 
         [0074]    Controller (CB)  103  is placed conveniently between patient and ESU  140   
         [0075]    CB  103  side, permanent cable  111  ( 3  branches) is attached to ESU  140  monopolar outlets  140   a  and  140   b , as well as ground pad outlet  140   c.    
         [0076]    Cable  4  of ground pad  2  is connected to CB  103  at outlet  103   a  or alternatively directly to ESU  140  ground pad outlet  140   c.    
         [0077]    Monopolar instrument  107  is connected by its power plug  108  to CB  103  via cable  9  to outlet  103   b.    
         [0078]    Proprietary cable (PC)  6  is permanently connected to SC  105 . Its extension is attached to the SB  103  at outlet  103   c  or through multi-connector  226  ( FIG. 9  or  FIG. 19 ). 
         [0079]    If trocar  145  was not removed or an instrument is inside the SC  105  prior to connecting the SC  105  to the powered CB  103 , audio and written messages will appear “Please remove instrument from SC.” 
       During Testing 
       [0080]    Whenever the limit switch, micro-switch or photocell indicates that the cannula is empty, the system goes into the following initial state awaiting an instrument so that a test may begin. LSC  120  is initially at 5V. USC  119  is initially at 5V or at 4000V as explained below. Initially and throughout the testing, the instrument is kept at ground potential and the contacts are connected to their respective voltages via individual resistors. The relays electrically disconnect the generator  140  from the instrument power plug  108  and electrically connect the testing circuit ground  470  to the instrument ground plug  108 . 
         [0081]    In another variant, only LSC  120  is kept at low voltage while USC  119  is at 4000V, or it is instantaneously turned on at the moment USC  119  is ceasing to have contact with the conductive distal tip portion (jaws  144 ) of the instrument  107 . LSC  119  is generally left “ON” at its typical voltage (approximately 5V or low voltage) as it does not affect anything. One alternative could be to turn it “OFF” (or zero volts) when it is not needed. 
         [0082]    Surgeon inserts the shaft  127  of an insulated monopolar instrument  107  into SC  105 . 
         [0083]    SC  105  is ON together with CB  103  before testing. 
         [0084]    Tip (jaws  144 ) of instrument  107  hits micro switch  125  ( FIG. 11 ) that signals CB  103  of an incoming device. 
         [0085]    CB  103  announces the presence of an instrument in the cannula  105 . 
         [0086]    Instrument tip (jaws  144 ) hits USC  119  ( FIG. 8A ), causing arcing and/or current flow to occur between it (e.g., 4000V) and the instrument  107  (ground). This is sensed and registered by CB  103 , and indicates that the exposed tip region (jaws  144 ) of the instrument  107  is now in the scanning section of the cannula  105  (in other embodiments USC  119  may be neutral initially or charged at a low voltage, such as 5V). 
         [0087]    Instrument tip (jaws  144 ) hits second sweeping contact LSC  120 , causing its voltage to drop to that of the instrument  107 . This is sensed and registered by CB  103 , and indicates that the exposed tip region (jaws  144 ) of the instrument  107  is still in the scanning section of the cannula  105 . The sequential detection of the tip (jaws  144 ) first by USC  119  and then LSC  120  provides confirmation that both USC and LSC are working correctly and are not defective or damaged. 
         [0088]    As the exposed tip (jaws  144 ) of the instrument  107  moves beyond LSC  120 , the insulated shaft  131  of the instrument touches LSC  120  and therefore the voltage of the LSC  120  is no longer pulled to the ground voltage of the instrument  107 . The return of LSC  120  to +5V indicates to the CB  103  that the insulated shaft  131  is touching the contacts and it is time to begin the test. At this point, USC  119  is at a high voltage of approximately 3000V to 4000V and the test for insulation defects begins. LSC  120  is disconnected via a high voltage relay  301 . CB  103  announces the beginning of the scanning test. A software based timer within the software of  FIG. 14  or a modification thereof is commenced for the allowed test duration (e.g., 5 sec) to allow a reasonable time for the scan to complete. 
         [0089]    The surgeon continues to push the instrument  107  deeper into the patient  1  through the cannula  105 , allowing the shaft  130  to pass along the sweeping contacts  119  and  120 . Any arcing sensed by USC  119  from this moment until the expiration of the Allowed Test Duration triggers an alarm and a message to the surgeon that the instrument is defective. If no arcing is sensed by USC  119  before the timer expires, the instrument is considered defect free. If found to be defective, the instrument  107  must be removed from the cannula  105  before another attempt at passing a test can be made. The generator  140  remains disconnected from the instrument  107  and ground pad  2  until a test is successfully passed, which then may generate a record of the result, and an “OK” sound along with the date and time of the test, and stored in the controller (or another storage device) for future reference. 
         [0090]    Any incoming inserted shaft will trigger the same cycle as above. 
         [0091]    The use of two sweeping contacts  119  and  120  and a micro-switch  125  allows:
       A. Detection of the presence of an instrument in the scanning cannula.   B. Confirmation of the operation of the sweeping contacts by their sequential detection of the exposed tip of the instrument.   C. Detection of the insulated portion  131  of the instrument shaft  127  once the LSC  119  returns to 5V.   D. Detection of insulation defects in the insulated portion of the instrument via sweeping with high voltage by the USC  120 .       
 
         [0096]      FIGS. 10 ,  10 A, and  11 A provide elevational and exploded isometrics of the scanning cannula  105  and the trocar  145 , plus an inside view of the scanning elements as situated within the scanning cannula head portion  105   a . The trocar  145  comprises a cap portion  145 B and a shaft  145 A having a tip portion  132 . The trocar  145  is used, while situated in the scanning cannula  105  to penetrate the abdominal wall of the patient until the scanning cannula is affixed deep enough as per the surgeon&#39;s discretion. At that point the trocar  145  is removed, leaving the through channel in the scanning cannula  105  free so that minimally invasive surgical devices can be inserted while protecting the insufflation pressure in the abdominal cavity. 
         [0097]      FIGS. 11 through 11  B and  12  through  12 F show sweeping contacts  119  and  120 , preferably made out of elastic conductor material and  FIGS. 11 ,  11 B,  12 ,  12 E and  12 F have a typical view of micro-switch  125 . 
         [0098]      FIG. 14  depicts a flow chart of the functionality of software that can be used with the scanning cannula.  FIGS. 15 and 16  illustrate a circuit diagram for a circuit that could be used with the software. 
         [0099]    The circuit diagram of  FIG. 16  illustrates the low voltage section, which also interacts with the high voltage section shown in  FIG. 15 , where a portion of the low voltage section is also shown. The low voltage section of  FIG. 16  generally contains digital circuits and software which handle the control and user interfaces. The high voltage section of the  FIG. 15  generally has parts which interact with the testing and the generator  140 , and where the sweeping contacts (upper and lower  119 ,  120  or single contact  155 ) connect to the controller  103 , and where the relays  301 ,  302 ,  303 ,  304  and  305  are housed. The two sections are separated to protect the more delicate circuits on the low voltage side from the high voltages present in the scanning and operation of the scanning cannula. The only link between the high voltage and low voltage sections are the optoisolators  450 ,  451  and  452 . 
         [0100]    The low voltage section of  FIG. 16  has two computer chips  455  and  456 . Chip  455  is the main chip and has the software described in the flowcharts set forth below, as depicted in  FIG. 14  or  FIG. 21 . The chip  455  with its software opens and closes the relays  301 ,  302 ,  303 ,  304 , and  305  and turns the testing high voltage supply on and off. The chip  455  with its software reads the status of the limit switch  125  and sweeping contact  155  or contacts  119 ,  120 . It also controls the LEDs and audio signals  308 , and transmits information to the second chip  456  to run the LCD display  306 . The second chip  456  takes information from chip  455  and displays it on the LCD display  306 . All of the connections for LEDs and audio signals, however, are driven by the main chip  455 . The inputs for USC  119  or  155  is connected via port  457 . Port  458  is used to connect the LSC  120  input if used. The ON/OFF power for the testing high voltage supply is connected at port  459 . The relays are controlled at port  454 . 
         [0101]    All components in the high voltage section ( FIG. 15 ) are controlled by and report to the main chip  455  through the optoisolators  450 ,  451 , and  452 . The testing high voltage supply is located in the high voltage section as are the relays and circuit to drive the lower sweeping contact. Variable resistors  460 ,  461 , and  462  allow the adjustment of the detection threshold, the testing voltage, and the testing current, respectively. The power plug  108  of the instrument  107  connects the generator  140  via relay  301 . The power plug  108  also connects to the ground of the testing circuit  470  via relay  305 . The relays  302 ,  303 , and  304  allow the connection of other lines for the instrument  107  (or other instruments) and/or the connection of a ground pad  2  to the controller  103 . A connection  477  connects the power supply to the USC  119  or sweeping contact  155 . Any detected arcing is amplified at circuit  476  and is transmitted to the main chip  455  via optoisolator  450 . 
         [0102]    If a lower sweeping contact  120  is used, processing is performed via circuit  478 . The OVERRIDE function connects at circuit  480  to communicate with the lower voltage section via optoisolator  452 . 
         [0103]    Circuits  482  and  483  ensure that whenever relays  301 ,  302 ,  303 , and  304  are open, relay  305  is closed, and vice-versa. 
         [0104]    The software of  FIG. 14  has three inputs plus a master power on/off switch and an override all disposed in the controller  103 . The three inputs are from the three scanning elements, i.e., the two contacts and the limit switch. 
         [0105]    The three scanning elements (inputs to the software) have the following functions:
       1. The upper contact (high voltage) is used to scan the shaft for insulation defects.   2. The lower contact (low voltage) is used to determine whether the insulated shaft or the exposed tip of the instrument is currently being scanned by the upper contact.   3. The limit switch (also called micro-switch in our documentation) is used to determine whether or not an instrument is present in the cannula.       
 
         [0109]    The software controls the following (has the following outputs):
       1. The testing high voltage power supply  472  (ON/OFF). When this is ON, the upper contact is at 4000V (or whatever high voltage is selected).   2. The relays  301 ,  302 ,  303  and  304  (closed or open) that connect/disconnect the instrument  105  and ground pad  2  from the generator  140  and disconnect/connect the testing circuit ground from the power plug  108 . If a test has been successfully passed or if the OVERRIDE is enabled, the relays  301 ,  302 ,  303  and  304  are closed, electrical energy flows from the generator  140  to the ground pad  2  and instrument  105  as with typical electrosurgery. At this time the relay  305  between the ground of the test circuit and the instrument  105  is open (disconnected) to protect the testing circuit from the generator  140 .   3. At all other times, the relays  301 ,  302 ,  303  and  304  are open, so that the ground pad  2  and instrument  105  are disconnected from the generator  140 , leaving the patient safely electrically isolated, and the relay  305  between the ground of the test circuit and the instrument is closed, allowing testing to occur.       
 
         [0113]    This software also sends information to a secondary microprocessor  304  that handles the LCD display  306 . The audio tones  308  and LEDs are also controlled by the software. 
         [0114]    If the OVERRIDE actuator  404  ( FIG. 20 ) is pressed at any time, the relays  301 ,  302 ,  303 , and  304  close to allow electrosurgery, the relay  305  opens to protect the testing circuit, and the software is bypassed and does not affect the system whatsoever. The OVERRIDE actuator  404  ( FIG. 20 ) can also be located in a position near the power switch or other locations that might serve the same purpose. 
         [0115]    The software within the controller  103  functions after initially powering on the scanning cannula, where the relays  301 ,  302 ,  303 , and  304  are open (disconnected), the relay  305  is closed, and where the testing high voltage power supply is off. Immediately upon being powered on, the controller checks the status at step  312  of the limit switch  125  to determine whether an instrument is present in the scanning cannula. If an instrument is present in the cannula upon power up, the controller displays a message at step  314  asking the user to remove it so that it may go through the scanning sequence in correct order. If the cannula is empty, the controller at step  316  requests that an instrument be inserted so that scanning may begin (the limit switch has not been activated). 
         [0116]    Whenever the cannula is empty and powered on, the testing sequence is ready to begin. The HV supply  110  is activated at step  318  thereby bringing the upper contact  119  to 4000V. The controller  103  waits for the presence of an instrument to initiate the scanning sequence. The software returns to this state any time that the cannula is empty. From here, the system is waiting for an instrument to enter the cannula so that testing may begin. 
         [0117]    At this point, in step  320 , the relays  301 ,  302 ,  303  and  304  are still open (disconnected) and the testing high voltage supply  140  is powered on. The user is requested to insert an instrument by the LCD display  306  and the scanning cannula software waits until an instrument is present in the cannula  105  at step  322 . 
         [0118]    Once a device has entered the cannula  105 , i.e., the limit switch  125  is pressed, the controller  103  waits for the upper contact  119  and then the lower contact  120  to sequentially detect the exposed tip  144  of the instrument  113 , whether through arcing or direct conduction between the exposed tip  144  and the contact  119  or  120  in question. The sequential detection of the tip  144  by the two contacts  119  and  120  acts as a verification that the contacts are working properly. Thus, the software waits until the upper contact  119  detects the tip  144  of the instrument  113  at step  324  and then sequentially waits until the lower contact  120  detects the tip  144  of the instrument  113  at step  326 . In general, the upper contact  119  (high-voltage) is used to scan the shaft  127  for insulation defects. The lower contact  120  (low-voltage) is used to determine whether the insulated shaft  127  or the exposed tip  144  of the instrument  107  is currently being scanned by the upper contact  119 . Once the tip  144  is no longer detected by the lower (low-voltage) contact  120 , the software at step  328  knows that the insulated shaft  127  of the instrument  113  is adjacent to the upper contact  119  and that the upper contact  119  is far enough away from the exposed tip  144  region so that arcing between the upper contact  119  and the tip  144  will not occur. Any arcing at the upper contact  119  from this point onward will be interpreted as an insulation defect. So, the software waits until the lower contact  120  does not detect the tip  144 , and therefore it detects the insulated shaft  127 . 
         [0119]    The test of the insulated shaft  127  begins at step  330 . A software based timer internal to the microprocessor software is commenced to allow a nominal amount of time (several seconds) for the surgeon to push the entire useful length of the shaft of the instrument into the cannula. Any arcing at the upper contact will be interpreted as an insulation defect. If the timer expires without an insulation defect being detected, the instrument will be deemed defect-free at step  332  and surgery will be permitted. A record of the result of the scanning test, along with the date and time of the test may be stored in the controller (or other storage media) for future reference. 
         [0120]    If a defect is found, the user is alerted at step  334 . The instrument must be removed to attempt another test. 
         [0121]    The timer is evaluated at step  336  to determine if any time remains. If so, the software returns step  330  and repeats the process. If the allotted time has expired, and if the instrument has passed the test and is considered defect-free, the surgery is allowed by reconnecting the generator  140  to the instrument  107  and ground pad  2  at step  338 . The relays close at step  340  while the testing high voltage supply is ON. 
         [0122]    As described above, if the OVERRIDE actuator  404  is pressed at any time, the relays close to allow electrosurgery and the CB&#39;s software is bypassed and does not affect the system whatsoever. The instrument is connected to the generator (generator relay is closed). To protect the testing circuit from the generator waveform, the relay  305  from the instrument power plug  480  to the controller  105  ground is open. 
         [0123]    For this reason, the functionality of the OVERRIDE actuator  404  ( FIG. 20 ) may be included in the flowchart at any point in the flowchart. The OVERRIDE actuator  404  ( FIG. 20 ) can be located at the power switch or other locations, e.g., the top of the scanning cannula  105 , which might serve the same purpose. 
         [0124]      FIGS. 13 ,  13 A,  13 B,  13 C,  18 A,  18 B, and  18 C show an alternative design of the Attachable Scanning Portion (ASP)  205  or  233  that may be attached to commercially available conventional cannulas  123 . This added variant expands the usability of the scanning benefits to virtually all existing cannulas, providing said available cannulas are made of non-conductive materials, such as non-conductive plastics, etc. The ASP  205  or  233  will be attached to the cannula  123  by the same mechanical mechanism as the trocar  145  was attached prior to removal, or it can alternatively have its own separate attachment mechanism. Only one sweeping contact  155  is being used in the example shown in  FIGS. 18A ,  18 B, and  18 C. Double sweeping contacts are shown in  FIGS. 13 ,  13 A,  13 B, and  13 C. 
         [0125]    With reference to  FIGS. 13 ,  13 A,  13 B and  13 C, the cannula  123  has slots  234  into which tabs  238  from the ASP  233  conformably attach and detach. The tabs  238  are controlled via a strap (see  FIG. 18D ) having buttons  239 . As the buttons are manually pushed into the ASP  233  (or  205  in  FIG. 18A ), the tabs  238  are forced toward the center axis of the ASP  233  (or  205 ) to release the contact with the slots  234 , and release the ASP  233  (or  205 ) from the cannula  123 . The process is reversed when the ASP  233  (or  205 ) is attached to the cannula  123 . 
         [0126]    In the variant shown in  FIGS. 18A ,  18 B, and  18 C, once micro-switch  125  is tripped, the sweeping contact  155  is charged initially with low voltage that is enough to “sense” the incoming conducting distal tip end of a monopolar device. Once the current flow through the instrument ceases, the voltage is raised instantaneously to high voltage for the remainder of the scanning. In another alternative for the single sweeping contact version of  FIGS. 18A ,  18 B, and  18 C, the sweeping contact is at approximately 3000V-4000V initially unless a test has been passed or failed. This means that the device will not wait for the micro-switch  125 . This may allow faster and more reliable results because there would be no start-up transition time when first activating a testing high voltage supply. 
         [0127]      FIG. 21  depicts a flow chart of the functionality of software that can be used with the scanning cannula  205  having one sweeping contact  155 . The controller  103  can use the same circuit ( FIGS. 15 and 16 ) used with the new software as described here. 
         [0128]    The software has two inputs plus a master power on/off switch and an override all disposed in the controller  103 . The override switch may also be disposed on the cannula  205 . The two inputs are from the two scanning elements, i.e., the one sweeping contact  155  and the limit switch  125 . 
         [0129]    The two scanning elements (inputs to the software) have the following functions:
       1. The single sweeping contact  155  (high voltage) is used to scan the shaft  127  for insulation defects and to determine which part of the instrument  107  (exposed tip (jaws  144 ) or insulated shaft  127 ) is currently being scanned.   2. The limit switch  125  (also called micro-switch) is used to determine whether or not an instrument  107  (or a trocar  145 ) is present in the cannula  205 .       
 
         [0132]    The software controls the following (has the following outputs):
       1. The high voltage power supply (ON/OFF)  459 . When this is ON, the upper contact is at approximately 4000V (or whatever high voltage is selected, such as approximately 3000V).   2. Relays  301 ,  302 ,  303  and  304  (closed or open) that connect/disconnect the instrument  107  and ground pad  2  from the generator  140  and a relay  305  that disconnects/connects the controller ground  470  from the instrument power plug  108 . When the relays  301 ,  302 ,  303 , and  304  are closed, electrical energy flows from the generator  140  to the ground pad  2  and instrument power plug  108  as with typical electrosurgery. When the relays  301 ,  302 ,  303  and  304  are open, the ground pad  2  and instrument  107  are disconnected from the generator  140 , leaving the patient safely electrically isolated. When the controller  103  ground to instrument power plug relay  305  is open the controller  103  circuits are safely isolated from the generator  140 . When this relay  305  is closed, the instrument power plug  108  is connected to the controller  103  ground to allow a scanning test to proceed.       
 
         [0135]    This software also sends information to a secondary microprocessor  304  that handles the LCD display  306 . The LED display  306  and/or audio tones  308  are also controlled by the software. 
         [0136]    If the OVERRIDE actuator  404  is pressed at any time, the relays  301 ,  302 ,  303  and  304  close to allow electrosurgery and cancel the scanning as applicable, and the software is bypassed to not affect the system whatsoever. For this reason, the OVERRIDE actuator  404  can also be located in a position near the power switch or other locations that might serve the same purpose. 
         [0137]    The software within the controller  103  functions after initially powering on the scanning cannula  205 , where the relays  301 ,  302 ,  303  and  304  are open (disconnected) and where the high voltage power supply via the generator  140  is off. Immediately upon being powered on, the controller  103  checks the status at step  512  of the limit switch  125  to determine whether an instrument is present in the cannula  205 . If an instrument is present in the cannula  205  upon power up, the controller displays a message at step  514  asking the user to remove it so that it may go through the scanning sequence in correct order. If the cannula  205  is empty, the controller  103  at step  516  requests that an instrument be inserted so that scanning may begin (the limit switch  125  has not been activated). 
         [0138]    Now the testing sequence is ready to begin. The HV supply  472  is activated at step  518  thereby bringing the contact  155  to approximately 4000V. The controller  103  waits for the presence of an instrument (such as  107 ) to initiate the scanning sequence. The software returns to this state any time that the cannula  205  is empty. From here, the system is waiting for an instrument to enter the cannula  205  so that testing may begin. 
         [0139]    At this point, in step  520 , the relays  301 ,  302 ,  303  and  304  are still open (disconnected), and the testing high voltage supply  472  is powered on. The relay  305  is closed so that testing may proceed. The user is requested to insert an instrument by the LCD display  306  and the scanning cannula software waits until an instrument is present in the cannula  205  at step  522 . 
         [0140]    Once a device has entered the cannula  205 , i.e., the limit switch  125  is contacted, the controller  103  waits for the single contact  155  to detect the exposed tip  144  of the instrument  113  at step  524 , whether through arcing or direct conduction between the exposed tip  144  and the contact  155  in question. Once the tip  144  is no longer detected by the contact  155  at step  526 , the software at step  528  has the program wait a predetermined amount of time (usually a couple of milliseconds, for example) to know that the insulated shaft  127  of the instrument  107  is adjacent to the contact  155  and that the contact  155  is far enough away from the exposed tip  144  region so that arcing between the contact  155  and the tip (jaws  144 ) will not occur. Any arcing at the contact  155  from this point onward will be interpreted as an insulation defect. So, the software waits the predetermined time to permit the user to push the shaft further into the cannula after the contact  155  does not detect the tip (jaws  144 ), and therefore it detects the insulated shaft  127 . 
         [0141]    The test of the insulated shaft  127  begins at step  530 . A software based timer is commenced to allow a nominal amount of time (several seconds) for the surgeon to push the entire useful length of the shaft of the instrument into the cannula  205 . Any arcing at the upper contact will be interpreted as an insulation defect. If the timer expires without an insulation defect being detected, the instrument will be deemed defect-free at step  532  and surgery will be permitted. This test applies here to either an attachable scanning device or an integrated cannula/scanning device, and the attachable scanning device can be attached with either one sweeping contact or two. 
         [0142]    If a defect is found, the user is alerted at step  534 . The instrument must be removed to attempt another test. A record of the result of the scanning test, along with the date and time of the test, may be stored in the controller (or other storage medium) for future reference. 
         [0143]    The test timer is evaluated at step  536  to determine if testing time remains. If so, the system continues to wait for an insulation defect to be detected or for the testing time to expire. If time has elapsed and no defects have been found, the instrument has passed the test and is considered defect free. Electrosurgery is allowed by reconnecting the generator  140  and ground pad  2  at step  538 . The relays  301 ,  302 ,  303  and  304  close at step  540  while the high voltage supply is off. The relay  305  is opened to protect the testing circuits. 
         [0144]    As described above, if the OVERRIDE actuator  404  is pressed at any time, the relays close to allow electrosurgery and the software is bypassed and does not affect the system whatsoever. The instrument  107  is connected to the generator  140  (generator relay  301  is closed). To protect the testing circuit from the generator waveform, the testing circuit ground relay  305  is open. 
         [0145]    For this reason, the functionality of the OVERRIDE actuator  404  may be included in the flowchart at any point in the flowchart, and the OVERRIDE actuator  404  can also be located at the power switch or other locations, e.g., the top of the attachable scanning cannula head  205  or  233 , that might serve the same purpose. 
         [0146]    The same circuit can be used for the single contact as is used for the two sweeping contacts, as described above and  FIGS. 15 and 16 , but with different software as shown in  FIG. 21 . 
         [0147]      FIG. 19  shows a typical situation where multiple scanning cannulas  105  are used in the same operation on a patient  1 . Each scanning cannula or attachable head  105  or  205  (or  233 ) is connected to a connector manifold  226  via scanning cannula cable  6  or  106 . Connecting manifold  226  is connected to the controller  103  via multi-channel cable  227 . This typical connection of multiple scanning cannulas  105  allows the usage of a single power source (the ESU/generator)  140  with various instruments as the instrument to be used has to be connected to cable  9  prior to insertion into a selected scanning cannula  105 . Following the short scan, once found to be free of defects, an activation of the ESU  140  via a foot switch (not shown) or the instrument&#39;s integrated activation buttons ( FIG. 20 ) will direct the RF energy to the connected instrument  107 . 
         [0148]      FIG. 20  depicts the interface between the user and the scanning cannula controller. The scanning cannula (SC) may be equipped with one or more LEDs as shown in  FIGS. 20 and 20A . An OVERRIDE actuator  404  is shown to activate the OVERRIDE function described above for the scanning cannula  105  or  205 . 
         [0149]    As an example, while using 3 LEDs: 
         [0150]    LED  401  is blue 
         [0151]    LED  402  is green 
         [0152]    LED  403  is red 
         [0153]    An example algorithm for the LEDs  401 ,  402 ,  403  is as follows:
       1. LED  401  (blue) is on steady once the scanning cannula is attached to the controller  103 . It flashes once the override button  404  is depressed, and goes back to steady blue only when the instrument that was inserted subject to the override command has been removed.   2. LED  402  (green) is turned on and flashing during the scan. LED  402  is on steady green after a positive scan as long as the passed instrument stays inside the scanning cannula. LED  402  is off when the instrument was removed or its scan failed.   3. LED  403  (red) is turned on flashing when a scan ends with negative results. It stays on flashing until the instrument is removed outside the scanning cannula or the OVERRIDE button is pressed.       
 
         [0157]    The same algorithm may be used for another design variant, where instead of using three LEDs, a single tri-color LED  405  is used. Audio tones may also be substituted for the lights of the LEDs or used concurrently with the LED lights. 
         [0158]    Any combination of the above described embodiments is within the scope of the invention. 
         [0159]    Although the present invention has been described in relation to endoscopic applications, the principles and the basic design of the scanning chamber  24  may apply to many industrial and general fields, where simple scanning of dielectric barrier defects is required. Further, even though a wireless embodiment is described herein, the same scanning principles may apply to a wired scanning cannula, i.e., a similar device that is wired to a controller with a multi-channel cable, branched and connected to the scanning cannula  10  at scanning chamber  24 . 
         [0160]    Although the invention has been described by reference to specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments unless the claims are specifically worded to do so, but otherwise that it have the full scope defined by the language of the following claims.