Surgical instrument and system

Abstract

An electrosurgical system includes an electrosurgical unit electrically coupled to a surgical retractor. The electrosurgical unit includes an RF output and an RF return. The surgical retractor includes a return pad electrically coupled to the RF return of the electrosurgical unit. The electrosurgical unit includes an RF output configured to be coupled to an electrosurgical device, such as an electrosurgical device configured in a monopolar mode. A controller is configured to determine an impedance in tissue at a surgical area electrically disposed between the RF output and the and the RF return. The surgical retractor includes a handle and a blade configured to interface with tissue. The blade includes a return electrode.

What is claimed is: 
     
         1 . An electrosurgical unit, comprising:
 an RF output configured to be coupled to an electrosurgical device;   an RF return configured to be coupled to a surgical retractor; and   a controller operably coupled to the RF output and the RF return, the controller configured to determine an impedance in tissue at a surgical area electrically disposed between the RF output and the and the RF return.   
     
     
         2 . The electrosurgical unit of  claim 1  comprising a detection circuit operably coupled to the RF return and the controller. 
     
     
         3 . The electrosurgical unit of  claim 2  wherein the detection circuit includes a return electrode monitoring circuit. 
     
     
         4 . The electrosurgical unit of  claim 1  wherein the controller includes a processor and memory device. 
     
     
         5 . The electrosurgical unit of  claim 1  comprising a RF circuit operably coupled to the controller and the RF output. 
     
     
         6 . The electrosurgical unit of  claim 1  wherein the controller is configured to output the determined impedance. 
     
     
         7 . The electrosurgical unit of  claim 6  wherein the output includes a visualization. 
     
     
         8 . The electrosurgical unit of  claim 1  wherein the determined impedance includes calculating the difference between a voltage at the RF output and a voltage at the RF return dived by a current received at the RF return. 
     
     
         9 . The electrosurgical unit of  claim 1  comprising a plurality of RF returns. 
     
     
         10 . An electrosurgical unit, comprising:
 an RF output configured to be coupled to an electrosurgical device;   a first RF return configured to be coupled to one of the electrosurgical device and a return pad dispersive electrode;   a second RF return configured to be coupled to a surgical retractor; and   a controller configured to determine an impedance in tissue at a surgical area electrically disposed between the RF output and the second RF return, and the controller configured to determine an impedance   
     
     
         11 . The electrosurgical unit of  claim 10  wherein the determined impedance includes calculating the difference between a voltage at the RF output and a voltage at the second RF return dived by a current received at the second RF return. 
     
     
         12 . The electrosurgical unit of  claim 11  wherein the controller is configured to determined a return electrode impedance from calculating the difference between a voltage at the RF output and a voltage at the first RF return dived by a current received at the first RF return.