The wake-up technique as a dual protector of spinal cord function during spine fusion

Intraoperative awakening is commonly used to evaluate voluntary motor function to lessen the risks of nerve damage during posterior spine fusion and Harrington rod instrumentation for idiopathic scoliosis. This is a report of intraoperative monitoring of tension in the soft tissues of patients with idiopathic scoliosis utilizing a strain-gauged distraction outrigger. The tension in soft tissues was found to drop following intraoperative awakening by an average of 52 N in the 14 patients monitored. The "wake-up" technique may aid in protecting the spinal cord from overdistraction by the increase in soft tissue tension present at the time of Harrington rod replacement in addition to providing a spot check of motor function. This increased tension may slightly repress curve correction.