Short Report: Pedicle Screw Stimulation Values with and without Insulated Dilators in Percutaneous Screw Placement

Area of Science:

• Spine Surgery
• Neuromonitoring
• Minimally Invasive Procedures

Background:

• Triggered electromyography (EMG) is crucial for intraoperative neuromonitoring during spine surgery.
• Current shunting through percutaneous pedicle screws can lead to inaccurate EMG threshold values, potentially causing false negatives.
• Minimally invasive spine techniques increase the complexity of screw placement and neuromonitoring.

Purpose of the Study:

• To investigate the impact of current shunting on triggered EMG threshold values during pedicle screw stimulation.
• To compare the threshold values obtained with and without an insulated dilator during percutaneous pedicle screw stimulation.
• To assess the risk of false-negative EMG results associated with current shunting in minimally invasive spine surgery.

Main Methods:

• A case study involving the stimulation of percutaneously placed pedicle screws.
• Comparison of stimulation threshold values with and without the use of an insulated dilator.
• Utilizing triggered electromyography (EMG) for intraoperative neuromonitoring.

Main Results:

• Stimulation with an insulated dilator yielded different threshold values compared to stimulation without one.
• Findings indicate a potential for increased risk of false-negative results due to current shunting.
• The use of insulated dilators may mitigate the effects of current shunting.

Conclusions:

• Current shunting presents a significant risk for false-negative triggered EMG results when stimulating pedicle screws.
• Insulated dilators are recommended during pedicle screw placement in minimally invasive surgery to improve neuromonitoring accuracy.
• Employing insulated dilators can enhance the reliability of triggered EMG by reducing current shunting-related false negatives.