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Updated: Jul 19, 2026
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A Spine Robotic-Assisted Navigation System for Pedicle Screw Placement
Published on: May 11, 2020
Automated intraoperative EMG testing during percutaneous pedicle screw placement
Burak M Ozgur1, Scott Berta, Vishal Khiatani
1Division of Neurosurgery, University of California, San Diego Medical Center, 200 West Arbor Drive, San Diego, CA 92103-8893, USA. bozgur@ucsd.edu
Summary
Electromyography (EMG) testing enhances safety in percutaneous spinal surgery by identifying problematic screw trajectories early. This technique allows for adjustments, improving pedicle screw placement and reducing nerve injury risk.
Area of Science:
- Spinal Surgery
- Neurosurgery
- Orthopedic Surgery
Background:
- Electromyography (EMG) screw testing is validated for open spinal instrumentation.
- Limited evidence exists for its use in percutaneous screw placement.
- Percutaneous techniques increase nerve injury risk due to lack of direct visualization.
Purpose of the Study:
- To assess the effectiveness of EMG testing during percutaneous pedicle screw placement.
- To demonstrate EMG's utility in minimizing nerve injury in minimally invasive spine surgery.
Main Methods:
- EMG testing was performed during percutaneous pedicle screw insertion in 20 patients (22 levels, 88 pedicles).
- Insulated k-wires and taps were stimulated using an automated EMG system.
- Low EMG threshold values (<10mA) triggered trajectory adjustments.
Main Results:
- Four k-wires (5%) required repositioning due to low EMG thresholds.
- One k-wire repositioning improved after tapping.
- Tap thresholds exceeded k-wire thresholds in 89% of pedicles, suggesting improved placement.
Conclusions:
- EMG testing effectively identifies suboptimal screw trajectories during percutaneous spinal surgery.
- Adjustments based on EMG feedback can confirm improved placement.
- EMG may enhance the safety of percutaneous techniques by mitigating risks associated with limited visualization.
