Patent ID: 8147421

Claim:
A method of finding a direction of a nerve from a surgical instrument, the method comprises: electrically stimulating a first stimulation electrode on a distal region of a surgical instrument configured to advance through tissue to create a distraction corridor with a first set of at least one stimulation current signal until a first initial bracket comprising a maximum stimulation current value and a minimum stimulation current value between which a first threshold stimulation current level must lie is determined; electrically stimulating a second stimulation electrode spaced apart from said first electrode with a second set of at least one stimulation current signal until a second initial bracket comprising a maximum stimulation current value and a minimum stimulation current value between which a second threshold stimulation current level must lie is determined; processing with a control unit communicatively linked to said first and second electrodes the determined first initial bracket and the determined second initial bracket, said processing including determining the first threshold stimulation current level by narrowing the first initial bracket to a first final bracket and determining the second threshold stimulation current level by narrowing the second initial bracket to a second final bracket; prior to completing the steps of determining the first and second threshold stimulation current levels, displaying on a display communicatively linked to said control unit, an initial indicator, based on said processing, indicating a general direction of the nerve from the surgical instrument; and upon completing the steps of determining the first and second threshold stimulation current levels, displaying on the display a subsequent indicator, based on said processing, indicating a more specific direction of the nerve from the surgical instrument.