Electromyography System

Abstract

Systems and methods for performing a surgical procedures on the spine are described, including a spinal access system. The spinal access system may have a stimulation cannula with a stimulation electrode at a distal end. The stimulation cannula is configured to be advanced along an access path toward a patient's lumbar spine while coupled to a nerve monitoring system configured to detect nerves in the path of the stimulation cannula by stimulating the stimulation electrode at the distal end of the stimulation cannula and monitoring an electrical current level determined after a neuro-muscular onset response is detected via one or more return electrodes positioned on the patient's leg.

What is claimed is: 
     
         1 . A spinal access system for performing a spinal surgical procedure, the spinal access system comprising:
 a stimulation cannula including a stimulation electrode at a distal end of the stimulation cannula configured to be advanced along an access path toward an operative site in the region of a patient's lumbar spine; and   a nerve monitoring system configured for performing nerve detection of a spinal nerve when the stimulation cannula is positioned in the access path toward the operative site in the region of the lumbar spine by stimulating the stimulation electrode at the distal end of the stimulation cannula and monitoring an electrical current level determined after a neuro-muscular onset response is detected via one or more return electrodes positioned on the patient's leg.   
     
     
         2 . The spinal access system of  claim 1 , wherein the nerve monitoring system repeatedly performs nerve detection while current intensity level of a stimulation pulse emitted by the stimulation electrode is varied over time. 
     
     
         3 . The spinal access system of  claim 1 , wherein the nerve monitoring system repeatedly performs nerve detection while current intensity level of a stimulation pulse emitted by the stimulation electrode is varied incrementally. 
     
     
         4 . The spinal access system of  claim 1 , wherein the nerve monitoring system visually displays an intensity level of a neuro-muscular response onset value for the spinal nerve. 
     
     
         5 . The spinal access system of  claim 1 , wherein the nerve monitoring system is configured to be operated by a surgeon to provide nerve detection warnings to alert the surgeon operating the nerve detection system that the spinal nerve is in close proximity to the stimulation electrode.