Surgical trocar with cutoff circuit

• US 5,599,347 A
• Filed: 09/07/1994
• Issued: 02/04/1997
• Est. Priority Date: 02/13/1991
• Status: Expired due to Term

• Current Assignee: Applied Medical Resources Corporation (Applied Medical Corporation)
• Original Assignee: Applied Medical Resources Corporation (Applied Medical Corporation)
• Inventors: Ritchart, Mark A., Hilal, Nabil, Hart, Charles C., Shabaz, Martin V.
• Primary Examiner(s): Sykes, Angela D.
• Assistant Examiner(s): PEFFLEY, MICHAEL F
• Application Number:
  US08/303,125
• Time in Patent Office: 881 Days
• Field of Search: 606/37-42, 606/45-50, 604/21, 604/22, 604/264, 604/272
• US Class Current: 606/42
• CPC Class Codes: A61B 17/3417 Details of tips or shafts, e.g. grooves, expandable, bendable; Multiple coaxial sliding cannulas, e.g. for dilating syringe needles A61M5/32; dilators A61M29/00
• CPC Class Codes: A61B 17/3476 Powered trocars, e.g. electrosurgical cutting, lasers, powered knives
• CPC Class Codes: A61B 17/3494 with safety means for protection against accidental cutting or pricking, e.g. limiting insertion depth, pressure sensors for the peridural space A61B17/3401
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 18/1487 Trocar-like, i.e. devices producing an enlarged transcutaneous opening
• CPC Class Codes: A61B 2017/32007 with suction or vacuum means
• CPC Class Codes: A61B 2017/320071 with articulating means for working tip
• CPC Class Codes: A61B 2017/320082 for incising tissue
• CPC Class Codes: A61B 2018/0066 without feedback, i.e. open loop control
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61M 13/00 Insufflators for therapeutic or disinfectant purposes , i.e. devices for blowing a gas, powder or vapour into the body hand-held units in which gas flow is produced by muscular energy at the moment of use B05B11/062
• CPC Class Codes: A61M 2210/10 Trunk
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus

Abstract

A surgical trocar includes an operative sleeve adapted for disposition across a tissue barrier and an obturator removably disposed in the sleeve. An obturator includes a cutting element which is operable to cut the tissue. The obturator and the operative sleeve can be advanced through the cut tissue and the obturator removed leaving the sleeve operatively disposed for further surgery. A cutoff and reset mechanism is responsive to a condition present when the obturator penetrates the tissue barrier to inhibit further cutting by the cutting element. A reset mechanism is manually operable through the conscious efforts of the surgeon to reset the trocar should further cutting be desired. The cutoff and reset mechanisms can be embodied mechanically as well as electrically and adapted to both mechanical and electrosurgical trocars.

Claims

1. A trocar system for penetrating a tissue wall in order to provide access for instruments extending into a body cavity of a patient, comprising:

an obturator having a shaft with a blunt distal tip;

a cannula having a working channel adapted to removably receive the obturator and to receive the instruments after the obturator has been removed from the cannula;

a cutting element disposed at the blunt distal tip of the obturator and extending beyond the cannula when the obturator is disposed in the cannula, the cutting element having properties for being electrically energized to cut tissue;

a power generator for generating a cutting signal;

conduction means for conducting the cutting signal from the power generator to the cutting element at the blunt tip of the obturator; and

means responsive to penetration of the tissue wall for inhibiting further electrical energizing of the cutting element in order to prevent further cutting of tissue by the cutting element.

2. The trocar system recited in claim 1 wherein the inhibiting means comprises means for inhibiting generation of the cutting signal by the power generator.

3. The trocar system recited in claim 2 wherein the electrical generator comprises:

a power electrode;

a control electrode; and

a conductor operable to provide continuity between the power electrode and the control electrode in order to activate the generator to produce the cutting signal.

4. The trocar system recited in claim 3 wherein the inhibiting means further comprises a switch disposed in the conductor of the generator and operable to break continuity between the power electrode and the control electrode to inhibit generation of the cutting signal by the electrode generator.

5. The trocar system recited in claim 1 wherein the inhibiting means comprises means for inhibiting conduction of the cutting signal by the conduction means between the electrical generator and the cutting element at the blunt tip of the obturator.

6. A trocar system for penetrating a tissue wall of a patient, in order to provide access for instruments extending into a body cavity of the patient, comprising:

an obturator having a shaft with a blunt distal tip;

a cannula having a working channel adapted to removably receive the obturator and to receive the instruments after the obturator has been removed from the cannula;

a cutting element disposed at the blunt distal tip of the obturator and having properties for being electrically energized to cut tissue;

first means operatively connected to the cutting element for electrically energizing the cutting element; and

second means responsive to a particular condition representative of penetration of the tissue wall by the blunt distal tip of the obturator for inhibiting further cutting of tissue by the cutting element.

7. The trocar system recited in claim 6 further comprising:

lockout means responsive to operation of the second means for preventing further operation of the energizing means; and

overriding means manually operable for overriding operation of the lockout means to permit further cutting of the tissue in the absence of the particular condition.

8. The trocar recited in claim 6 wherein the second means includes means responsive to a static condition which is present at the inner surface of the tissue wall for inhibiting further cutting by the cutting element.

9. The trocar system recited in claim 8 wherein the second means includes means responsive to pneumoperitoneum pressure within the cavity for inhibiting further cutting by the cutting element.

10. The trocar system recited in claim 8 wherein the second means includes means dependent on the presence of tissue within the tissue wall and the absence of tissue beyond the inner surface of the tissue wall for inhibiting further cutting by the cutting element.

11. The trocar system recited in claim 6 wherein the second means includes means responsive to a dynamic condition which first occurs in proximity to the inner surface of the wall, for inhibiting further cutting by the cutting element.

12. The trocar system recited in claim 11 wherein the second means includes means responsive to an absence of force resisting movement of the distal tip into the cavity for inhibiting further cutting by the cutting element.

13. A trocar system for penetrating wall having an interior surface defining a body cavity of a patient, comprising:

an obturator having a shaft with a blunt distal tip;

a cutting element disposed at the distal tip and having properties for being energized to cut tissue;

means for being electrically energizing the cutting tip;

a switch including in the energizing means and having an open state permitting energizing of the cutting tip and a closed state inhibiting energizing of the cutting tip;

an electrically sensor disposed at the distal tip and responsive to conditions present when the distal tip is in proximity to the inner surface of the tissue wall to provide a penetration signal;

to automatically switch to the open state, thereby inhibiting further cutting by the cutting element.

14. The trocar system recited in claim 13 wherein the sensor is an optical sensor.

15. The trocar system recited in claim 14 wherein the optical sensor is an infrared sensor.

16. The trocar system recited in claim 13 wherein the sensor is an electrical sensor.

17. The trocar system recited in claim 16 wherein the electrical sensor is an impedance sensor.

18. The trocar system recited in claim 13 wherein the sensor is a mechanical sensor.

19. The trocar system recited in claim 18 wherein the mechanical sensor is a pressure sensor.

20. An electrosurgical trocar system for penetrating a tissue wall in order to provide access for instruments extending into a body cavity of a patient, comprising:

an electrical generator producing an electrical power signal;

an electrosurgical trocar operatively connected to the electrical generator and including an obturator having a distal tip responsive to the electrical power signal of the generator to cut the tissue of the wall as the obturator penetrates the wall;

a cannula having a working channel adapted to removably receive the obturator and to receive the instruments after the obturator has been removed from the cannula; and

a cutoff circuit included in one of the electrical generator and electrosurgical trocar, the cutoff circuit being responsive to full penetration of the wall by the distal tip of the electrosurgical trocar to inhibit the electrical power signal produced by the electrical generator and to prevent further cutting of the tissue by the distal tip.

21. The electrosurgical trocar system recited in claim 20 wherein the cutoff circuit comprises:

a sensor responsive to an environmental condition present when the distal tip is in proximity to the inner surface of the wall, to provide a cutoff signal; and

means responsive to the cutoff signal to inhibit the electrical power signal.

22. The electrosurgical trocar system recited in claim 21 wherein the means responsive to the cutoff signal includes:

the series combination of the first switch and a second switch operable to introduce the electrical power signal to the distal tip;

the first switch being automatically responsive to the cutoff signal to inhibit introduction of the power signal to the distal tip; and

the second switch being manually operable to inhibit introduction of the electrical power signal to the distal tip.

23. The electrosurgical trocar system recited in claim 22 wherein the sensor is an electrical interference receiver and the environmental condition is the absence of electrical interference at the distal tip.

24. An electrosurgical trocar system for penetrating a body wall having an inner surface defining a body cavity, the system comprising:

an electrical generator having a power electrode and properties for producing an electrical power signal;

a control circuit included in the generator;

switch means included in the control circuit of the generator and having a closed state enabling presentation of the power signal on the power electrode and an open state inhibiting presentation of the power signal on the power electrode;

an electrosurgical trocar operatively connected to the generator and having a distal tip carrying a cutting element, the cutting element being responsive to the power signal from the generator to penetrate the body wall;

an electric sensor operatively connected to said switch means and having characteristics for sensing an environmental condition which exists when the distal tip of the trocar is in proximity to the inner surface of the wall, the sensor being responsive to the environmental condition for providing a cutoff signal; and

the switch means being responsive to the cutoff signal from the sensor for automatically assuming the open state to inhibit further cutting by the cutting element.

25. The electrosurgical trocar system recited in claim 24 wherein the switch means includes:

a first switch having an open state and a closed state, the first switch being responsive to the cutoff signal from the sensor to assume the open state;

a second switch in series with the first switch and being manually operable between an open state and a closed state; and

the switch means having the closed state only when both the first switch and the second switch are in their respective closed states.

26. The electrosurgical trocar system recited in claim 25 wherein the first switch maintains the open state even in the absence of the cutoff signal until the second switch is manually operated to the open state.

27. The electrosurgical trocar system recited in claim 25 wherein the first switch consecutively assumes a first state, a closed state, and a reset state, the first switch automatically moves from the open state to the closed state in response to absence of the cutoff signal and automatically moves from the closed state to the reset state in response to the presence of the cutoff signal, and the switch means further comprises:

reset means manually operable to move the first switch from the reset state to the open state.

28. The electrosurgical trocar system recited in claim 27 wherein the reset means is included in the second switch and is manually operated when the second switch is moved from its closed state to its open state.

29. A trocar system for penetrating a tissue wall of a patient, comprising:

a trocar including a housing and a cannula;

an obturator having a handle, and a shaft extending from the handle, the shaft having a blunt distal tip and being adapted for insertion through the housing and the cannula of the trocar;

an electrical actuated cutting element disposed at the distal tip of the obturator;

means included in the obturator for moving the cutting element through the tissue wall;

a sensor included in the obturator and responsive to a particular condition representative of penetration of the tissue wall by the cutting element to provide an electrical cutoff signal; and

a logic circuit responsive to the cutoff signal of the sensor for inhibiting further cutting of the tissue by the cutting element of the obturator.

30. The trocar system recited in claim 29 wherein the logic circuit includes:

a switch having first and second electrodes, an actuator and a lockout element;

the lockout element having a first position in aligned relationship with the actuator and lockout relationship with the first electrode, a second position permitting contact between the first electrode and the second electrode to facilitate cutting by the cutting element, and a third position in lockout relationship with the first electrode and misaligned relationship with the actuator; and

the actuator being operable to reset the switch by moving the lockout element from the third position to the first position.

31. The trocar system recited in claim 30 wherein the actuator includes means disposed between at least a portion of the handle and the switch responsive to movement of the handle of the obturator toward the housing of the trocar to move the switch from the third position to the first position.

32. A trocar system for penetrating a tissue barrier of a patient, comprising:

a cannula having a proximal end and a distal end;

an obturator adapted for removable disposition within the cannula and having a shaft with a blunt cutting tip adapted to cut the tissue barrier;

logic means for electrically controlling the cutting of the blunt cutting tip;

cutoff means included in the logic means and responsive to a condition representative of penetration of the tissue barrier by the cutting tip to inhibit further cutting by the blunt cutting tip; and

reset means included in the logic means and manually operable for overriding the cutoff means to permit further cutting by the blunt cutting tip of the obturator.

33. The trocar system recited in claim 32 wherein the obturator includes a shield mounted on and slidable along the obturator shaft and the cutoff means includes a cutoff mechanism responsive to the condition to slide the shield along the obturator shaft to cover the cutting tip.

34. The trocar system recited in claim 32 wherein the cutting tip includes an electrosurgical element energizable to cut the tissue barrier.

35. The trocar system recited in claim 34 wherein the cutoff means includes a mechanism responsive to the condition to inhibit further energizing of the electrosurgical element.

36. The trocar system recited in claim 34 further comprising a sensor responsive to the condition representative of penetration to provide an electrical signal;

wherein

the cutoff means is responsive to the signal from the sensor to inhibit further cutting by the electrosurgical element; and

the reset means is manually operable in the absence of the signal from the sensor to override the cutoff means.

37. A method for controlling the cutting of an electrical actuated tissue barrier by a blunt cutting tip disposed at the distal end of a trocar obturator, comprising the steps of:

cutting the tissue barrier with the blunt cutting tip of the obturator;

controlling the cutting of the tissue barrier by the blunt cutting tip through operation of a logic circuit;

sensing a condition representative of substantially complete penetration of the tissue barrier by the blunt cutting tip;

automatically inhibiting further cutting of the cutting tip due to operation of the logic circuit in response to the sensing of the condition; and

resetting the logic circuit to permit further cutting of the tissue barrier.

38. The method recited in claim 37 further comprising the steps of:

providing the obturator with a shaft and a shield movable relative to the shaft to cover the cutting tip; and

during the inhibiting step moving the shield relative to the shaft to cover the cutting tip and thereby inhibit further cutting of the tissue barrier.

39. The method recited in claim 37 further comprising the steps of:

providing the cutting tip in the form of an electrosurgical element at the distal end of the obturator;

during the cutting step energizing the electrosurgical element to cut the tissue barrier; and

during the inhibiting step de-energizing the electrosurgical element in response to the condition to inhibit further cutting of the tissue barrier by the electrosurgical element.

40. The method recited in claim 37 further comprising the steps of:

providing a conductor for energizing the electrosurgical element;

providing a switch in the logic circuit, the switch having a closed state permitting energizing of the electrosurgical element through the conductor and an open state inhibiting the energizing of the electrosurgical element through the conductor;

during the inhibiting step automatically moving the switch to the open state to inhibit energizing of the electrosurgical element; and

during the resetting step manually moving the switch to the closed state to energize the electrosurgical element and permit further cutting of the tissue barrier.

41. An electrosurgical trocar system for cutting the tissue of a body wall, comprising:

an electrical generator producing an electrical power signal;

an electrosurgical trocar including a housing and a cannula extending from the housing;

an obturator including a handle and a shaft extending from the handle, the shaft of the obturator being adapted for insertion through the cannula of the trocar and having a distal tip responsive to the electrical power signal of the generator to cut the tissue of the wall as the obturator penetrates the wall;

a cutoff circuit included in one of the electrical generator and the electrosurgical trocar, the cutoff circuit being responsive to the full penetration of the body wall by the distal tip of the electrosurgical trocar to inhibit the electrical power signal produced by the electrical generator and to prevent further cutting of the tissue by the distal tip;

a sensor included in the cutoff circuit and responsive to an environmental condition present when the distal tip is in proximity to an inner surface of the wall, to provide a cutoff signal;

means included in the cutoff circuit and responsive to the cutoff signal for inhibiting the electrical power signal, the inhibiting means including a first switch and a second switch in series combination and operable to introduce the electrical power signal to the distal tip;

the first switch being automatically responsive to the cutoff signal to inhibit introduction of the power signal to the distal tip; and

the second switch being disposed in the obturator handle and manually operable by squeezing the handle of the obturator against the housing of the trocar to inhibit introduction of the electrical power signal to the distal tip.