Patent ID: 7470236

Claim:
A method for assessing the proximity of a spinal nerve relative to a distal end of at least one probe or surgical tool being introduced towards at least one of a lumbar region and thoracic region of a patient's spine, said lumbar region and said thoracic region of said spine having a ventral column and a dorsal column, said ventral column including a plurality of vertebral bodies and a plurality of intervertebral discs disposed in between said vertebral bodies, said vertebral bodies and intervertebral discs each having an anterior aspect, a posterior aspect opposite from said anterior aspect, and a lateral aspect extending between said anterior and posterior aspects, said dorsal column including a plurality of bone elements extending from said vertebral bodies to form a spinal canal that contains and protects the spinal chord, said spinal nerve exiting from said spinal canal and disposed generally parallel to a longitudinal axis of said spine along said lateral aspect, the method comprising: (a) emitting a stimulus signal from an electrode disposed on a probe or surgical tool as said probe or tool is introduced towards a lateral aspect of at least one of a vertebral body and an intervertebral disc of at least one of a lumbar region and thoracic region of a patient's spine; (b) electromyographically monitoring muscles coupled to said spinal nerve to determine if a predetermined neuro-muscular response is elicited by the stimulus signal; (c) increasing the intensity level of said stimulus signal until said predetermined neuro-muscular response is elicited by said stimulus pulse and stopping the emission of said stimulus signal immediately after said predetermined neuro-muscular response is detected; and (d) communicating to an operator said intensity level of said stimulus signal required to elicit said predetermined neuro-muscular response, wherein said intensity level required to elicit said predetermined neuro-muscular response represents the proximity of said spinal nerve to said probe or surgical tool.