Previous studies have shown how triggered electromyogram (EMG) pedicle screw stimulation can be used to effectively test correct pedicle screw placement in the lumbar and thoracic vertebrae. Most papers agree that if more than 6mA of current are needed to elicit a response the screw is correctly placed in the bone. If there is a response with less than 6mA there is a strong likelihood of a breach of the pedicle wall or invasion of the spinal canal. Typically this triggered EMG stimulation is done after all the screws have been placed with a ball-tipped probe and is paired with intraoperative fluoroscopy to ensure correct placement of the screws. Another method of testing the current for each screw is with a powered screwdriver, which can stimulate and give a reading as the surgeon places each screw. Both of these methods are currently used by surgeons, however the powered screwdriver has been found to be a faster method. The investigator's aim with this study is to compare these two methods of testing triggered EMG values. The investigators plan on doing this by testing each screw with both the ball-tipped probe and the powered screwdriver, in order to see if there are any statistically significant differences between the readings.

The purpose of the study is to compare two methods of testing triggered EMG values. All study measurements will be recorded during the surgical procedure. No follow up is required with the patient involved and no personal health information will be recorded from the patients.

Inclusion Criteria:

• between the ages of 8-21 years
• diagnosis of adolescent idiopathic scoliosis (AIS)
• scheduled to receive a spinal fusion

Exclusion Criteria:

• diagnosis of any other type of scoliosis (infantile, juvenile, congenital, neuromuscular, etc)

Patients between the ages of 8-21 years of age with a diagnosis of adolescent idiopathic scoliosis (AIS) who will be receiving a spinal fusion.