Redundant pneumatic circuit for reliability enhancement of vitrectomy instruments

1. An apparatus enhancing the reliability of a pneumatically driven surgical tool, comprising:

a source of regulated pneumatic pressure;

an isolation valve fluidly coupled to the source of regulated pneumatic pressure and fluidly coupled to both a primary drive valve and a backup drive valve;

a first circuit selection valve and a second circuit selection valve, each coupled with a respective first and second chamber of a surgical tool and coupled with both the primary drive valve and the backup drive valve;

a first pressure sensor fluidly coupled between the first circuit selection valve and the first chamber of the surgical tool;

a second pressure sensor fluidly coupled between the second circuit selection valve and the second chamber of the surgical tool; and

a control system containing a processor and a non-transitory computer readable medium that contains instructions which, when executed by the processor, cause the processor to:

monitor the pneumatic pressure from the first pressure sensor and the second pressure sensor;

determine when the pneumatic pressure flowing through the first pressure sensor and the second pressure sensor is normal or abnormal;

actuate the isolation valve to selectively allow pneumatic pressure to flow to the primary drive valve and suppress pneumatic pressure to the backup drive valve and to suppress pneumatic pressure to flow to the primary drive valve and allow pneumatic pressure to the backup drive valve; and

actuate the first and second circuit selection valves to selectively receive pneumatic pressure from the primary drive valve or the backup drive valve and to alternatively drive and vent the first chamber and the second chamber of the surgical tool regardless of whether the isolation valve allows the flow of pneumatic pressure through the primary drive valve or the backup drive valve.

2. The apparatus of claim 1 , wherein the first chamber and the second chamber of the surgical tool is separated by a diaphragm connected to a cutting device, wherein the cutting device performs a cutting function when the diaphragm is actuated by pneumatic pressure alternatively driving and venting the first chamber and the second chamber.

3. The apparatus of claim 1 , wherein the instructions further cause the processor to determine that the pneumatic pressure flowing through the first pressure sensor and the second pressure sensor is abnormal by determining when differential pressure between the first pressure sensor and the second pressure sensor is below a threshold value.

4. The apparatus of claim 1 , wherein the instructions further cause the processor to apply a remediation step to return the differential pressure between the first pressure sensor and the second pressure sensor to exceed a threshold value after determining that the pneumatic pressure flowing through the first pressure sensor and the second pressure sensor is abnormal, wherein the remediation step is applied prior to actuating the isolation valve to suppressing pneumatic pressure to flow to the primary drive valve and allowing pneumatic pressure to the backup drive valve.

5. The apparatus of claim 4 , wherein the remediation step comprises adjusting a valve duty cycle of the primary drive valve.

6. A method of enhancing the reliability of a pneumatically driven surgical tool, comprising:

monitoring, using one or more pressure sensors, a pneumatic pressure of a first fluidic line from first circuit selection valve and a second fluidic line from second circuit selection valve, wherein each of the first circuit selection valve and second circuit selection valve are coupled with a respective first and second chamber of a surgical tool and are respectively coupled with both a primary drive valve and a backup drive valve;

determining that the pneumatic pressure flowing through one or both of the first fluidic line and the second fluidic line is normal or abnormal;

determining when to switch to a backup drive valve mode by actuating an isolation valve to suppress pneumatic pressure flowing to the primary drive valve and allowing the pneumatic pressure to flow to the backup drive valve and actuating the first and second circuit selection valves to selectively receive pneumatic pressure from the backup drive valve and to alternatively drive and vent the first chamber and the second chamber of a surgical tool.

7. The method of claim 6 , wherein the first chamber and the second chamber of the surgical tool is separated by a diaphragm connected to an cutting device, wherein the cutting device performs a cutting function when the diaphragm is actuated by pneumatic pressure alternatively driving and venting the first chamber and the second chamber.

8. The method of claim 6 , wherein determining that the pneumatic pressure flowing through one or both of the first fluidic line and the second fluidic line is abnormal comprises determining when differential pressure between the first pressure sensor and the second pressure sensor is below a threshold value.

9. The method of claim 8 , further comprising:

after determining that the pneumatic pressure flowing through one or both of the first fluidic line and the second fluidic line is abnormal and before actuating the isolation valve and the first and second circuit selection valves, applying a remediation step to return the differential pressure between the first pressure sensor and the second pressure sensor to exceed a threshold value.

10. The method of claim 9 , wherein the remediation step comprises adjusting a valve duty cycle of the primary drive valve.

11. The method of claim 9 , further comprising:

after determining, using the one or more pressure sensors, that the remediation step was not successful in returning the differential pressure between the first pressure sensor and the second pressure sensor to exceed the threshold value, actuating the isolation valve and the first and second circuit selection valves to allow the pneumatic pressure to flow to the backup drive valve and to alternatively drive and vent the first chamber and the second chamber of a surgical tool.

12. The method of claim 11 , further comprising:

after actuating the isolation valve and the first and second circuit selection valves to allow the pneumatic pressure to flow to the backup drive valve and to alternatively drive and vent the first chamber and the second chamber of a surgical tool, monitoring, using the one or more pressure sensors, the pneumatic pressure of the first fluidic line from first circuit selection valve and the second fluidic line from the second circuit selection valve;

determining that the pneumatic pressure flowing through one or both of the first fluidic line and the second fluidic line is abnormal.

13. The method of claim 12 , wherein determining that the pneumatic pressure flowing through one or both of the first fluidic line and the second fluidic line is abnormal comprises determining when differential pressure between the first pressure sensor and the second pressure sensor is below a threshold value.

14. The method of claim 13 , further comprising

after determining that the pneumatic pressure flowing through one or both of the first fluidic line and the second fluidic line is abnormal, applying the remediation step to return the differential pressure between the first pressure sensor and the second pressure sensor to exceed a threshold value.

15. The method of claim 14 , further comprising:

after determining, using the one or more pressure sensors, that the remediation step was not successful in returning the differential pressure between the first pressure sensor and the second pressure sensor to exceed the threshold value, actuating the isolation valve, the primary drive valve, the backup drive valve, and the first and second circuit selection valves to terminate operation of the surgical tool.

16. A non-transitory computer readable medium that contains instructions which, when executed by a processor, cause the processor to:

monitor, using one or more pressure sensors, a pneumatic pressure of a first fluidic line from first circuit selection valve and a second fluidic line from second circuit selection valve, wherein each of the first circuit selection valve and second circuit selection valve are coupled with a respective first and second chamber of a surgical tool and are respectively coupled with both a primary drive valve and a backup drive valve;

determine when the pneumatic pressure flowing through one or both of the first fluidic line and the second fluidic line is normal or abnormal;

determine when to switch to a backup drive valve by actuating an isolation valve to suppress pneumatic pressure flowing to the primary drive valve and allowing the pneumatic pressure to flow to the backup drive valve and actuating the first and second circuit selection valves to selectively receive pneumatic pressure from the backup drive valve and to alternatively drive and vent the first chamber and the second chamber of a surgical tool.

17. The computer readable medium of claim 16 , containing further instructions which, when executed by the processor, cause the processor to:

after determining that the pneumatic pressure flowing through one or both of the first fluidic line and the second fluidic line is abnormal and before actuating the isolation valve and the first and second circuit selection valves, apply a remediation step to return the pneumatic pressure of the first fluidic line and the second fluidic line to normal values.

18. The computer readable medium of claim 17 , wherein the remediation step comprises adjusting a valve duty cycle of the primary drive valve.

19. The computer readable medium of claim 17 , containing further instructions which, when executed by the processor, cause the processor to:

after determining, using the one or more pressure sensors, that the remediation step was not successful, actuate the isolation valve and the first and second circuit selection valves to allow the pneumatic pressure to flow to the backup drive valve and to alternatively drive and vent the first chamber and the second chamber of a surgical tool.

20. The computer readable medium of claim 19 , containing further instructions which, when executed by the processor, cause the processor to:

after actuating the isolation valve and the first and second circuit selection valves to allow the pneumatic pressure to flow to the backup drive valve and to alternatively drive and vent the first chamber and the second chamber of a surgical tool:

monitor; using the one or more pressure sensors, the pneumatic pressure of the first fluidic line from first circuit selection valve and the second fluidic line from the second circuit selection valve;

determine that the pneumatic pressure flowing through one or both of the first fluidic line and the second fluidic line is abnormal;

apply an additional remediation step to return the pneumatic pressure of the first fluidic line and the second fluidic line to normal values;

determine, using the one or more pressure sensors, that the additional remediation step was not successful; and

actuate the isolation valve, the primary drive valve, the backup drive valve, and the first and second circuit selection valves to terminate operation of the surgical tool.